Light source unit, optical device, predetermined light using method, service providing method, and service providing system

Abstract

To provide light having optical characteristics suitable for a request for each optical application field and to optimize expression with high presence and highly accurate detection / measurement / imaging / light control or the like. Alternatively, in an optical application field or a service providing field, convenience, high added value, high reliability (high accuracy), and high expressiveness (for example, presence or reality) are provided to a user.SOLUTION: Each optical path of radiation light from the plurality of light emitting sources passes through a predetermined optical member having a minute step or a minute discontinuous place of a surface. Then, for each of the radiation lights from the different light sources, "the intensities of the lights whose optical path length difference between the different optical paths exceeds the coherence length are added to generate each predetermined light". The individual predetermined lights generated in this way are emitted toward the outside of the light source unit. An object may be irradiated with the predetermined light, and the predetermined light obtained from the object may be used. In addition, the predetermined light obtained from the object may be used to provide a service.SELECTED DRAWING: Figure 9F

Description

[Technical Field]

[0001] The present embodiment relates to the technical field of controlling the characteristics of light itself, the field of measurement using light, the field of utilizing light, or the field of providing services using light. [Background technology]

[0002] The properties of light itself are not limited to wavelength characteristics, intensity distribution characteristics, and phase distribution characteristics (including wavefront characteristics), but are also known to have various attributes such as directivity and coherence.

[0003] Known application fields using light include imaging technology, which places an image sensor at the image-forming position of an object, and application fields that utilize technologies such as spectral characteristic measurement technology, length measurement technology, and display technology for the object to be measured. Furthermore, application fields such as imaging spectrum, which combines the above imaging technology and the above spectral characteristic measurement technology, and 3D measurement, which combines the above imaging technology and the above length measurement technology, have recently developed. There are also application fields that utilize the measurement results of the amount of reflection, transmission, absorption, and scattering of light, or their changes over time.

[0004] Known application fields other than those utilizing the detection results and measurement results using light include display technology, optical processing technology, optical control technology, and optical communication technology.

[0005] Known fields for providing services using light include the technical field of providing services to users by utilizing various information obtained in the above-mentioned optical application fields. The provision of services to users is not limited to providing information to users or providing and controlling an optimal user environment, but also includes all service provision methods leading to the provision of two-way (mutual) services between users and the technology.

[0006] One service provision field involves providing services to users by utilizing activities in a virtual space formed on a network. For example, optical measurement data from the real world is used to simulate a pseudo-real world in cyberspace. Another known service provision method is to optically display the details of activities, such as attractions, that occur in cyberspace to users. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-222239 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-206449 [Patent Document 3] Patent No. 4657379 Summary of the Invention [Problem to be solved by the invention]

[0008] Each of the above light-related technical fields requires various (desirable) optical properties, and therefore it is desirable to provide optical properties suited to the requirements of each light-related technical field or optical application field.

[0009] For example, high-quality optical properties are required in fields such as display technology, imaging technology, optical control technology, and optical communication technology (technology for transmitting information via light). In recent years, there has been a trend in display and imaging technologies toward more realistic representations than ever before. As a method for achieving this sense of realism, there has been a growing trend toward the use of three-dimensional (3D) and vivid image representations. One way to generate these high-quality optical properties or optical properties that enable vivid representation is to provide light that produces little or no optical interference noise. However, achieving these three-dimensional (3D) and vivid image representations requires high-speed processing and transmission (transfer) of huge amounts of data (information). It is also necessary to provide high-quality signals that enable this large-volume data processing and transmission.

[0010] To realize high-precision detection, measurement, imaging, or optical control using light, high reliability and high detection / measurement accuracy are desired for detection, measurement, imaging, and optical control. One means for achieving high reliability and high precision of light may be to provide a method for reducing optical interference noise.

[0011] Alternatively, there may be cases where miniaturization and weight reduction of the optical device or optical measurement unit are desired. Furthermore, in relation to the above, provision of high quality services to users may be desired.

[0012] In addition to the above, it is also possible to provide a method for generating predetermined light having desirable or relatively appropriate characteristics in various application fields using light, an optical characteristic conversion unit, or a light source, a predetermined light utilization method, a service provision method, and a service provision system using the same.

[0013] Furthermore, it is also possible to provide an imaging method, a detection method, a detection method, or a display method that utilizes the above-mentioned predetermined light, or to provide an optical measurement unit or an optical device that utilizes these methods.

[0014] In Patent Document 1, the tilt angle of the light emitted from multiple light sources is changed for each light source to improve the inspection accuracy on the surface of the target object (semiconductor wafer). Using multiple light sources tends to lead to an increase in the complexity and size of the device. On the other hand, using a single light source causes a problem of increased optical interference noise because the phase difference between the light emitted at different tilt angles is always fixed.

[0015] Patent Document 2 describes a method for reducing optical interference noise by passing light passing through a transparent optical element with different thicknesses in different regions through a common optical fiber. However, to achieve high-precision detection, measurement, and imaging, further reduction of optical interference noise is desired.

[0016] In Patent Document 3, a solid-state imaging device has a pixel memory inside, which allows the exposure time to be set independently for each pixel, enabling ultra-high speed imaging. However, if optical interference noise is mixed into the light irradiated onto or reflected from the measurement object during ultra-high speed imaging, the quality of the captured image will be significantly reduced.

[0017] The above explanation has explained the need to provide light with optical properties suited to the requirements of each optical application field, and to provide highly realistic expression and highly accurate detection / measurement / imaging / optical control, etc. However, it is not limited to this, and it is also possible to provide convenience, high added value, high reliability (high accuracy), and high expressive power (for example, realistic feeling and reality) to users in optical application fields and service provision fields by methods other than providing light with good optical properties.

[0018] That is, user convenience may be improved by providing a hands-free environment for the user, or by providing functions for adding or automatically selecting the amount of information that the user receives visually. For example, a highly convenient service / service system or an optical device with high operability may be provided by utilizing the user's eye movements, eyelid and eyebrow movements such as blinking / winking, facial expressions, voice content, body movements such as gestures, and finger and hand (arm) movements for input or operation.

[0019] Furthermore, a method (function, device, or element) for collecting user biometric information in real time, with high accuracy, and in a simple manner may be provided, thereby realizing convenience for users, high added value, and high reliability. For example, collected user biometric information may be used as an identification function or authentication function (biometric authentication) to prevent fraud and prevent unintended inappropriate actions by the user, thereby providing a highly reliable service. Furthermore, a comfortable service or service system may be provided by inferring the user's mood or health state from facial expressions, voice, movement characteristics, breathing, pulse, changes in blood components, etc., and providing the user with an appropriate environment based on the inference results.

[0020] Alternatively, as an example of a method for providing users with high expressive power (for example, a sense of realism or reality), an environment (service system) capable of clear and detailed three-dimensional expression may be provided. [Means for solving the problem]

[0021] Each optical path of the emitted light from the multiple light sources passes through a predetermined optical member having minute steps or minute discontinuities on the surface. Then, for each of the emitted light from the different light sources, "the intensity of the light between the different optical paths whose optical path length difference exceeds the coherence length is added to generate individual predetermined light." The individual predetermined light thus generated is emitted toward the outside of the light source unit. This predetermined light may be irradiated onto an object, and the predetermined light obtained from the object may be used. The predetermined light obtained from the object may also be used to provide a service. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a configuration diagram showing an example of an overall system overview. [Figure 2] FIG. 2 is a diagram illustrating the relationship between optical properties required (desired) in various technical fields. [Figure 3] FIG. 3 is an explanatory diagram of how a collection of light beams with different wavelengths forms a wave train. [Figure 4] FIG. 4 is an explanatory diagram of an experimental system for measuring wave-train characteristics using the optical interference phenomenon. [Figure 5] FIG. 5 illustrates the interference characteristics between a train of single waves, one of which is delayed. [Figure 6A] FIG. 6A shows the experimental results of measuring the wave-train characteristics. [Figure 6B] FIG. 6B is a diagram illustrating the relationship between successive wave trains predicted based on the experimental results of FIG. 6A. [Figure 7A] FIG. 7A is an explanatory diagram of a basic optical system layout using an optical property conversion element. [Figure 7B] FIG. 7B illustrates a specific example of the structure of the optical property conversion element. [Figure 7C]FIG. 7C is an explanatory diagram of a method in which an optical property conversion element utilizes the phase asynchronous property between successive wave trains. [Figure 7D] FIG. 7D illustrates another embodiment regarding the specific structure of the optical property conversion element. [Figure 7E] FIG. 7E illustrates another application example relating to the specific structure of the optical property conversion element. [Figure 8] FIG. 8 is a diagram illustrating the effect of the optical characteristic conversion element in reducing noise in the spectral characteristic. [Figure 9A] FIG. 9A is an explanatory diagram of a basic optical configuration that is frequently used in this embodiment. [Figure 9B] FIG. 9B is an explanatory diagram of a specific embodiment of the basic optical configuration. [Figure 9C] FIG. 9C is an explanatory diagram of another specific embodiment of the basic optical configuration. [Figure 9D] FIG. 9D illustrates a simple method for cutting the wavefront continuity at each traveling wave cross-sectional position. [Figure 9E] FIG. 9E illustrates the difference in wavefront continuity between a general imaging lens and a Fresnel lens. [Figure 9F] FIG. 9F is a diagram illustrating an embodiment in which wavefront discontinuity is applied. [Figure 9G] FIG. 9G is a diagram illustrating another embodiment in which wavefront discontinuity is applied. [Figure 9H] FIG. 9H illustrates the relationship between the microscopic reflection direction and the macroscopic reflection direction in a multi-segment light reflecting element. [Figure 9I] FIG. 9I is an explanatory diagram of an application of FIG. 9G or FIG. 9H. [Figure 10A] FIG. 10A is an explanatory diagram of the relationship between biological system components and corresponding absorption wavelengths. [Figure 10B] FIG. 10B is an explanatory diagram of the structure of the human eyeball. [Figure 11A] FIG. 11A is an explanatory diagram of an embodiment example relating to the internal structure of a hybrid light-emitting section. [Figure 11B] FIG. 11B is a diagram illustrating the internal structure of the near-infrared light-emitting phosphor. [Figure 11C] FIG. 11C is an explanatory diagram of a method for producing a near-infrared light-emitting phosphor. [Figure 12A] FIG. 12A is an explanatory diagram of an embodiment example relating to an integrated structure of a light source unit and a measurement unit. [Figure 12B] FIG. 12B is an explanatory diagram of another embodiment relating to an integrated structure of a light source unit and a measurement unit. [Figure 13] FIG. 13 is a diagram illustrating the principle of the cause of optical noise generation in this embodiment from another perspective. [Figure 14A] FIG. 14A is a diagram illustrating an example of an optical noise reduction method. [Figure 14B] FIG. 14B is a diagram illustrating another embodiment of the optical noise reduction method. [Figure 14C] FIG. 14C is a diagram illustrating an application example of an optical noise reduction method. [Figure 14D] FIG. 14D shows the optical noise reduction effect when using the application example described in FIG. 14C. [Figure 15A] FIG. 15A is an explanatory diagram comparing the characteristics of a single-mode optical fiber and a multi-mode optical fiber. [Figure 15B] FIG. 15B is an explanatory diagram of the types and characteristics of multimode optical fibers. [Figure 15C] FIG. 15C is a diagram illustrating the mode of light passing through the core region of an optical fiber. [Figure 16A] FIG. 16A is an explanatory diagram of the generation of an intensity center of gravity shift using mode addition within an optical fiber. [Figure 16B] FIG. 16B is an explanatory diagram of an optical noise reduction method using the deviation of the intensity center of gravity. [Figure 16C] FIG. 16C is a diagram illustrating the relationship between an optical property conversion element and optical noise reduction. [Figure 17A] FIG. 17A is a diagram illustrating the relationship between the angle of incidence with respect to the normal to the incident surface of a predetermined optical member and the optical noise reduction effect. [Figure 17B] FIG. 17B is a diagram illustrating the relationship between the number of angle divisions of the optical property conversion element and the optical noise reduction effect. [Figure 18A]FIG. 18A is a diagram illustrating an example of an optical arrangement in a light source unit. [Figure 18B] FIG. 18B is an explanatory diagram of an embodiment mainly relating to the electronic circuit arrangement in the light source unit. [Figure 19A] FIG. 19A is a diagram illustrating a data format showing a time-varying light emission pattern. [Figure 19B] FIG. 19B is an explanatory diagram regarding a communication control sequence between the host and the light source unit. [Figure 19C] FIG. 19C is an explanatory diagram of an example of a control signal format for controlling the timing of starting light emission. [Figure 20A] FIG. 20A is an explanatory diagram showing the extraction and flow of information in this embodiment. [Figure 20B] FIG. 20B is a classification explanatory diagram showing the information content extracted in this embodiment. [Figure 20C] FIG. 20C shows a method for removing disturbance noise for each measurement location / content within the measurement object. [Figure 21A] FIG. 21A shows a basic data processing method in this embodiment for time-series changing spectral characteristics and image signals. [Figure 21B] FIG. 21B shows another embodiment relating to a data processing method for time-series changing spectral characteristics and image signals. [Figure 21C] FIG. 21C shows an application example relating to a data processing method for image signals and spectral characteristics using exposure by pulsed light emission. [Figure 22] FIG. 22 is a diagram illustrating the characteristics of a charge accumulation type signal receiving unit. [Figure 23A] FIG. 23A is an explanatory diagram of an example of signal processing (data processing) leading to generation of a reference signal after removal of a DC component. [Figure 23B] FIG. 23B is a diagram illustrating an example of a second information extraction method for each wavelength or each pixel. [Figure 24A] FIG. 24A is an explanatory diagram of an experimental optical system used in a signal processing experiment using a charge-storage type signal receiver. [Figure 24B] FIG. 24B is a diagram illustrating the spectral characteristics of the irradiated light and the detected light with respect to the measurement object. [Figure 25A] FIG. 25A shows the time-dependent change characteristics of the detected light amount for each of different wavelengths of light. [Figure 25B] FIG. 25B shows the time-dependent change characteristics of the detected light amount for each of different wavelengths of light. [Figure 26A] FIG. 26A shows an enlarged view of the inside of the imaging element used in this embodiment. [Figure 26B] FIG. 26B is a diagram illustrating a portion of a driving circuit in the image sensor used in this embodiment. [Figure 26C] FIG. 26C is a diagram illustrating the operation timing in the drive circuit described in FIG. 26B. [Figure 27A] FIG. 27A is an explanatory diagram of an embodiment in which the light source unit and the measurement unit are integrated. [Figure 27B] FIG. 27B is an explanatory diagram of the internal structure of the optical device when a 3D color imaging element is used in the measurement section. [Figure 28A] FIG. 28A is an explanatory diagram of the procedure for acquiring a 3D color image (video). [Figure 28B] FIG. 28B is an explanatory diagram of a method for capturing an image of a reflected light pattern using light at the wavelength of the light source over the entire measurement distance range. [Figure 28C] FIG. 28C is an explanatory diagram of a method for capturing an image of a reflected light pattern with light of a light source wavelength for each measurement distance range. [Figure 28D] FIG. 28D is a diagram illustrating the timing of light emission from the light source unit and exposure of the measurement unit during detailed distance measurement. [Figure 28E] FIG. 28E is an explanatory diagram of a distance measurement method that combines multiple pixels. [Figure 28F] FIG. 28F shows a combined illumination and exposure method that reduces the effects of speckle noise. [Figure 28G] FIG. 28G is an explanatory diagram of a signal detection state in a measurement unit that monitors the amount of speckle noise. [Figure 28H] FIG. 28H is an explanatory diagram of a signal detection state in a measurement unit that reduces the influence of speckle noise. [Figure 29A] FIG. 29A is a diagram illustrating the structure of a linear variable bandpass filter. [Figure 29B]FIG. 29B is an explanatory diagram of another embodiment in which a light source unit and an imaging element are combined. [Figure 30A] FIG. 30A is a diagram illustrating the relationship between input devices and output devices for a predetermined service providing domain in cyberspace. [Figure 30B] FIG. 30B illustrates an example of an input / output device configuration to a predetermined service providing domain in cyberspace. [Figure 30C] FIG. 30C illustrates another example of an input / output device configuration to a predetermined service providing domain in cyberspace. [Figure 31A] FIG. 31A is an explanatory diagram of a method for adjusting the size between the real space and the display contents in the cyberspace. [Figure 31B] FIG. 31B shows an example of an authentication environment when joining a predetermined service providing domain using biometrics. [Figure 31C] FIG. 31C is an explanatory diagram of a detailed example of authentication using biometric measurements. [Figure 32] FIG. 32 is an explanatory diagram of an embodiment of providing a time-controllable service in cyberspace. [Figure 33A] FIG. 33A is a diagram illustrating the four-dimensional coordinate axis directions as seen from the imaging element. [Figure 33B] FIG. 33B is an explanatory diagram of a four-dimensional mesh structure that captures changes in the surface shape of a measurement object in this embodiment. [Figure 33C] FIG. 33C is a diagram illustrating the data structure of a four-dimensional mesh in this embodiment. [Figure 34A] FIG. 34A is an explanatory diagram of a mapping concept used in a time-operable service providing domain in cyberspace. [Figure 34B] FIG. 34B shows a diagram for explaining the procedure up to the generation of a four-dimensional image (video) to be displayed to the user using mapping technology. [Figure 34C] FIG. 34C shows an example of a method for rendering and transforming coordinates of an individual four-dimensional mesh structure on a map. [Figure 34D] FIG. 34D is an explanatory diagram of a method for adjusting color intensity in accordance with the lighting conditions within the map. [Figure 34E]FIG. 34E is an explanatory diagram of a coordinate conversion method for three-dimensional display for the user. DETAILED DESCRIPTION OF THE INVENTION

[0023] The predetermined light generating method and optical property changing unit, light source, predetermined light utilization method, detection method, imaging method, display method, optical measurement unit, optical device, service provision method, and service provision system in this embodiment will be described below with reference to the drawings.

[0024] First, in order to make it easier to understand the entire explanation, a table of contents regarding the explanation of this embodiment will be shown. Chapter 1: Overview of the system used in this embodiment and the optical characteristics required for each optical application field Section 1.1 Overview of the system used in this embodiment Section 1.2 Overview of optical properties required for each optical application field Chapter 2 Basic Optical Properties Used in This Embodiment Section 2.1 Wave trains consisting of a collection of different wavelengths Section 2.2 Relationship between different wave trains and interference characteristics of light Section 2.3 Generation of special optical properties using wave-train characteristics Section 2.4 Optical noise reduction effect on spectral characteristics Chapter 3 Example of an embodiment for changing the optical characteristics between two waves emitted from the same light-emitting unit Section 3.1 Basic optical configuration used in this embodiment Section 3.2 Specific examples of basic optical configurations Section 3.3 Other Optical Configuration Examples Chapter 4 Hybrid Light Source and Its Usage Section 4.1 Relationship between biological components and absorption wavelengths Section 4.2 Example of hybrid light source internal structure Section 4.3 Materials and structure of near-infrared emitting phosphors and their production methods Section 4.4: An embodiment in which the light source unit and the measurement unit are integrated into a compact unit Chapter 5: Other Examples of Optical Noise Reduction Section 5.1 Characteristics of speckle noise patterns Section 5.2 Characteristics of various optical fibers and characteristics of light passing through the core region Section 5.3 Speckle noise pattern reduction method using mode characteristics in optical fiber Section 5.4 Optical noise reduction effect Chapter 6 Light source capable of emitting arbitrary waveforms in the time series direction Section 6.1 Optical system layout with high-speed control of light emission amount Section 6.2 Example of internal structure of light source Section 6.3 Example of light emission waveform setting format Section 6.4 Example of communication control of light emission Chapter 7 Combining Optical and Electrical Noise Reduction Section 7.1 High-precision measurement methods in optical application fields Section 7.2 Various examples of application of lock-in amplification technology Section 7.3 Structure of charge-storage signal receiver Section 7.4 Example of signal processing for charge accumulation signals Section 7.5 Example of demonstration experiment results Chapter 8: Combination of a light source unit and a measurement unit with a built-in image sensor Section 8.1 Internal structure of the image sensor and data acquisition timing in this embodiment Section 8.2 Combination of a measurement unit with a built-in image sensor and a light source unit Section 8.3 Distance measurement procedure Section 8.4: How to reduce the impact of laser speckle noise on measurements Section 8.5 Hyperspectral detection method using irradiation wavelength control Chapter 9 Service Provision Section 9.1 Examples of input / output device configurations when providing services Section 9.2 Examples of service provision Section 9.3 Example of data format for 4D data obtained by measurement Section 9.4 Mapping Process Chapter 1: Overview of the system used in this embodiment and the optical characteristics required for each optical application field Section 1.1: Overview of the service providing system used in this embodiment 1 shows a service providing system 14 used in this embodiment. Light emitted from a light source unit 2 is irradiated onto an object 20 via an optical propagation path 6. The light obtained from the object 20 is then incident on a measurement unit 8 via the optical propagation path 6 again. However, this is not limiting, and the light emitted from the light source unit 2 may be incident on the measurement unit 8 directly via the optical propagation path 6. In another embodiment, the light emitted from the light source unit 2 may reach a display unit 18 via the optical propagation path 6, and predetermined information may be displayed on the display unit 18.

[0025] The measurement device 12 in this embodiment is composed of a light source unit 2, a measurement unit 8, and an in-system control unit 50. In addition, an application field (various optical application fields) adaptation unit 60 exists outside the measurement device 12. Each of the sections 62 to 76 in the application field (various optical application fields) adaptation unit 60 can individually exchange information with the in-system control unit 50.

[0026] For example, information obtained as a result of measurement in the measurement unit 4 and each of the sections 62 to 76 in the application field (various optical application fields) adaptation unit 60 are used in conjunction with each other to provide services to users.

[0027] The service providing system 14 in this embodiment is composed of the measurement device 12, the application field (various optical application fields) adaptation unit 60, and an external system 16, and is configured to be able to provide a variety of services to users. Here, the remaining part of the service providing system 14, excluding the external system 16, functions independently as the optical device 10.

[0028] As a specific application, an example of providing a service related to remote medical care will be described. In this case, the medical / welfare-related test processing unit 70 operates and the information obtained from the measurement unit 8 can be used to assist in remote diagnosis. Specifically, the blood glucose level obtained by analyzing the data collected from the measurement unit 8 can be used to diagnose diabetes. Furthermore, the pulsation waveform obtained at the same time can be used to diagnose arrhythmias related to heart disease.

[0029] For example, let us consider a processing example in which arrhythmia is detected in a pulsation waveform while measuring a specific user's blood glucose level. The specific user's pulsation waveform is extracted in the signal processing unit 42 and transferred to the characteristic analysis / analysis processing unit 62 via the signal / information conversion unit (including decoding / demodulation processing) 44 and the system control unit 50. The characteristic analysis / analysis processing unit 62 then analyzes the pulsation waveform and performs pattern matching with a standard waveform and a lesion waveform. As a result, arrhythmia can be detected and a defect in the heart can be predicted. The arrhythmia detection result and information on the predicted defect in the heart are then transmitted to the medical / welfare-related test processing unit 70 via the system control unit 50.

[0030] Next, the medical / welfare-related examination processing unit 70 provides information (for example, by email) to the family doctor in the external system 16 via the information transmission path 4. Furthermore, if this specific user has previously concluded a contract with a predetermined insurance company (non-life insurance company), the medical / welfare-related examination processing unit 70 automatically provides information (for example, by email) to the insurance company (non-life insurance company). As a result, a service can be provided that handles troublesome procedures such as arranging hospitalization and processing medical fee reductions without imposing a burden on the user.

[0031] Furthermore, if a patient is undergoing medical treatment for an illness or a specific disease, the treatment adaptation control / processing unit 68 may operate to allow a doctor to remotely monitor the progress of the treatment. In other words, by tracking changes over time in blood glucose levels and pulse waveforms, a doctor in a remote location can understand the progression of the disease and the progress of recovery.

[0032] In addition to the above, the user's health information may be used to provide any other service. For example, when signing a contract for non-life insurance such as automobile insurance or unemployment insurance, the non-life insurance company may use the optical device 10 to check the health condition of the contracted user. A service may then be provided that sets the amount of compensation for damages based on the information obtained from the optical device 10.

[0033] Alternatively, information obtained from the optical device 10 may be used to set interest amounts and loan conditions when a user deposits money in a bank or when a bank lends money to a user (or a company run by the user).

[0034] As another example of a service provision form, information obtained from the optical device 10 may be used in educational settings. For example, a student's concentration level and drowsiness can be predicted from pulse rate, respiratory rate, eye movement, and eyelid movement. Based on the student's concentration level and drowsiness information obtained from the optical device 10, the content of the lecture can be changed as appropriate. This improves educational efficiency.

[0035] Another possible application of this service provision format is monitoring abnormalities in public facilities. When people become "stressed" or "excited," their heartbeat (pulse rate) tends to increase. Terrorists are often "stressed" or "excited" inside just before committing an attack, and their faces are often stiff from the tension. Therefore, by remotely operating a surveillance camera and measuring the pulse rates of an unspecified number of people simultaneously, it is possible to identify people with abnormally high pulse rates and contracted facial muscles.

[0036] In this embodiment, the optical device 10 may serve as an entrance to cyberspace by utilizing the information transmission path 4. (That is, the optical device 10 can be directly connected to cyberspace via the information transmission path 4.) Examples of services provided that serve as an entrance to cyberspace include personal authentication when entering cyberspace, searching for and guiding to the most suitable location for each user after entering cyberspace, acting on behalf of the user in active actions within cyberspace, and providing security protection, among other services.

[0037] In this embodiment, the optical device 10 (or the service providing system 14 therein) can automatically input and identify a blood vessel pattern or a fundus pattern at any part of the user's body, or perform face authentication or body shape authentication using a visible light camera built into the measurement unit 8. Therefore, in this embodiment, it is possible to provide a personal authentication service when entering cyberspace by using user-related information collected by the optical device 10. Furthermore, a personal authentication service may be provided using any method other than those described above (for example, voiceprint detection).

[0038] As an example of the physical form of the optical device 10 as a gateway to this cyberspace, the camera section of a personal computer or a mobile terminal (such as a smartphone or tablet) may be used.

[0039] Furthermore, a wearable terminal that can be worn by a user may be used as the physical form of the display unit 18 in the optical device 10. This wearable terminal that can be worn by a user may take any physical form, such as glasses, a hat, a helmet, or a bag.

[0040] For example, in glasses-type devices or devices worn directly by the user to realize VR (Virtual Reality) or AR (Augmented Reality), there is a location that comes into direct contact with the user's skin. At least a portion of the measuring unit 8 in the optical device may be disposed in this area that comes into direct contact with the user's skin.

[0041] By measuring the content of specific components such as noradrenaline in the blood through blood analysis, the psychological state of the user wearing the device, such as "tension" or "excitement," can be estimated. Additionally, the location of contraction of the facial muscles in the user's face can also be used to estimate the user's psychological state. Furthermore, as mentioned above, the pulse rate of a person captured on a remote camera can also be used to identify subjects who are in a "tension" or "excitement" state. Furthermore, in this embodiment, the activity of individual neurons in the user's head can be monitored. Therefore, the optical device 10 can be used to enable efficient access to cyberspace from the user.

[0042] Conventional methods for users to take active actions in cyberspace have required, for example, vocalization or finger operations such as keying. As a result, approaching cyberspace using conventional technology has taken a significant amount of time. In contrast, in this embodiment, the optical device 10 automatically and quickly predicts the user's psychological state and intentions, allowing for rapid and appropriate responses in cyberspace. Therefore, in this embodiment, the user can quickly receive the information 72 they desire and respond to cyberspace without requiring the user to perform cumbersome actions such as vocalization or finger movements.

[0043] Furthermore, various non-optical sensors 52 within the optical device 10 can be utilized to provide a high level of user convenience in dealing with cyberspace. For example, a case will be described in which a gyroscope or acceleration sensor is disposed as the various non-optical sensors 52 and detects the movement of the user's head or a part of the user's body (e.g., a hand or finger). When the user shakes their head while displaying an image (video) on the display unit 18 using a glasses-type wearable device such as VR or AR, the display screen rotates accordingly. When the user leans forward or leans back, the user moves forward or backward on the display screen. Here, when attempting to move quickly in cyberspace, for example, in a game, the response speed of the gyroscope or acceleration sensor is limited. In this case, predicting the user's psychological state and intentions and responding quickly and appropriately to cyberspace significantly improves the user's convenience in cyberspace.

[0044] An example of a service provided to a user through cooperation between the information providing unit 72, collected information storage 74, and signal processing unit 42 in the service providing system 14 is shown below. For example, consider a service providing example in which a menu screen is displayed on the VR screen or AR screen of a wearable device (e.g., glasses or a helmet) worn by the user. If the optical device 10 estimates the user's "likability" (or degree of discomfort) at the same time as detecting the user's line of sight, it is possible to instantly (in a short time) display a screen that the user prefers.

[0045] For example, 1. A wearable device such as VR or AR is incorporated into the display unit 18, 2. The gyroscope and acceleration sensor in the non-optical sensors 52 detect the movement of the user's head and fingers (or hands), 3. The signal processing unit 42 uses the user's biological signal measured by the measurement unit 8 to output information about the user's biological status. 4. When the system control unit 50 integrates and uses the above information, An identity in cyberspace is formed corresponding to the user who uses the optical device 10. Any service can be provided to this identity in cyberspace. Furthermore, it is possible to provide further services to the user by operating a robot placed in real space via cyberspace.

[0046] For example, an autonomous walking robot installed in a remote location can be operated to provide tourism services to users. Also, an autonomous walking robot installed in a hospital or facility can be operated to provide nursing care services from a distance. In conventional technology, operating an identity in cyberspace or operating a robot in real space required voice input or the user's finger (or hand) movements. Using the optical device in this embodiment eliminates the need for cumbersome voice input or finger movements, enabling high-speed operation. This significantly improves the convenience of providing services in this embodiment.

[0047] Another embodiment of providing services using cyberspace may be marketing applications. For example, the optical device 10 may estimate the user's emotions and intentions one by one while displaying predetermined images or videos on a VR or AR screen via the information providing unit 72. Images, videos, and audio displayed when the user expresses a favorable impression or interest are then appropriately stored in the collected information storage unit 74. The external system 16 collects the information (images, videos, and audio) stored in the collected information storage unit 74 via the information transmission path 4 at an appropriate time. The external system 16 may then analyze the collected information to identify products with purchasing power and provide the information to sales companies of the corresponding products for a fee.

[0048] In the present embodiment, personal information management is extremely important in providing services in cyberspace. Therefore, among the services provided in the present embodiment, the personal information management service itself is a very important service. When a specific user enters cyberspace and engages in activities within cyberspace, an account ID (identification) is used to identify the individual user. When the user's health information and preference information obtained from the optical device 10 is linked to the account ID, it is linked to personal information.

[0049] As an example of providing a service in this embodiment, a personal information management agent may be resident in the collected information storage unit 74 or the characteristic analysis / analysis processing unit 62. Information such as "which facial muscles of the user are contracted," "the content ratio of each component in the blood," or "which nerve cells are active (firing (nerve impulse)")" is analyzed in the signal processing unit 42. Then, using this information, advanced judgments such as "estimation of user emotions," "estimation of user preferences," and "estimation of user intentions" are made in the characteristic analysis / analysis processing unit 62. Then, the information obtained by this characteristic analysis / analysis processing unit 62 is stored in the collected information storage unit 74 as appropriate. Then, in response to a request from the external system 16, the necessary information is transmitted to the external system 16 via the information transmission path 4.

[0050] In the example of service provision in this embodiment, the personal information management agent links transmittable external range information to each piece of information obtained by the characteristic analysis / analysis processing unit 62. Therefore, transmittable external range information is set for all information stored in the collected information storage unit 74. Then, for each information transmission request from the external system 16, the personal information management agent determines whether or not transmission to the outside is possible. By providing the personal information management service within the optical device 10 in this way, highly reliable personal information protection is possible.

[0051] Another example of a service provision application of this embodiment may be a tool for creating artificial intelligence (for training artificial intelligence). For example, the artificial intelligence here may be a "multiple-input, multiple-output parallel processing method with learning function" used in deep learning technology or quantum computer technology.

[0052] Examples of complex analysis / processing suitable for multi-input, multi-output parallel processing include image analysis and image understanding, language processing and understanding, and advanced judgment adapted to complex situations. These tasks are given simultaneously to both the human being (22) and the AI. The answer given by the human can then be considered the correct answer, and learning feedback can be applied to the AI ​​to approach that correct answer.

[0053] These tools may be executed in cyberspace. In this case, the AI ​​to be trained is installed in advance on the external system 16, and the correct answer given by a human can be communicated to the AI ​​from the optical device 10 (or the application field adaptation unit 60) via the information transmission path 4.

[0054] Examples of service provision are not limited to the above, and any service may be provided in which the optical device 10 is connected to a cyberspace constructed on an external system 16 via an information transmission path 4.

[0055] Section 1.2 Overview of optical properties required for each optical application field 2 shows a list of required (desired) optical characteristics 102 for each optical application field 100. In particular, this embodiment can comply with the required (desired) optical characteristics 102 enclosed in a square frame.

[0056] The optical application field 100 to which this embodiment is applied is diverse as shown in Fig. 2. However, this embodiment is not limited to this, and all application fields 100 related to light in some way (including displays using light) are targets of this embodiment.

[0057] Chapter 2 Basic Optical Properties Used in This Embodiment Section 2.1 Wave train of light containing different wavelengths Light is generally divided into panchromatic light and monochromatic light based on the wavelengths it contains. Laser light, in particular, is thought of as single-wavelength light. However, strictly speaking, all light contains light of different wavelengths. For example, the wavelength width of the light emitted from a gas laser or solid-state laser is relatively narrow. However, even within the same laser, the wavelength width of the light emitted from a semiconductor laser (laser diode) is relatively wide, often with a half-width of wavelength of around 2 nm.

[0058] Figure 3 shows the characteristics when light of wavelengths within the wavelength width Δλ is gathered. Here, Figure 3(c) shows the progression of light with a central wavelength λ0, while Figures 3(a) and (e) show the progression of light with wavelengths λ0-Δλ / 2 and λ0+Δλ / 2. Figures 3(b) and (d) show the progression of light with wavelengths λ0-Δλ / 4 and λ0+Δλ / 4. Finally, Figure 3(f) shows the result when all wavelengths are combined. The collection of light formed by the gathering of light of wavelengths within the wavelength width Δλ is called a wavetrain.

[0059] If the peak positions for all light beams are the same at the center of Figure 3, the combined wave train, Figure 3(f), will form the largest peak at the center. As you move left and right from the center of Figure 3, the phases of the different wavelengths of light become increasingly shifted. At the left and right edges of Figure 3, the phases of the different wavelengths of light become completely unbalanced. When a phase shift occurs between Figures 3(a) to (e) in this way, the amplitude of the entire wave train, combining them, decreases in the peripheral direction.

[0060] The wavelength width Δλ means the wavelength width of the wavelength light included in the light emitted from the light source unit 2. For example, the spectral intensity characteristics (light intensity characteristics for each wavelength) of the light emitted from the light source unit 2 often have non-uniform spectral distribution characteristics within the wavelength width. In this case, the wavelength half width (the wavelength range having half the intensity of the maximum intensity in the wavelength direction) or e -2 Width (e relative to maximum intensity in wavelength direction) -2 The wavelength range having an intensity of Δλ may be called the wavelength width Δλ.

[0061] Furthermore, if the light source unit 2 emits multi-wavelength light (panchromatic light), the wavelength resolution in the measurement unit 8 may be considered to correspond to the wavelength width Δλ. For example, in the measurement unit 8 described later in FIG. 22, one preamplifier 1150 (detection cell) simultaneously detects light of different wavelengths. The wavelength range of wavelength light detected by one preamplifier 1150 (detection cell) corresponds to the wavelength width Δλ. However, the spectral sensitivity characteristics (wavelength dependence of signal detection sensitivity characteristics) detected by this one preamplifier 1150 (detection cell) may be non-uniform. In this case, the wavelength half width (wavelength range with half the detection sensitivity of the maximum detection sensitivity in the wavelength direction) or e -2 Width (e relative to maximum detection sensitivity in the wavelength direction) -2 The wavelength range over which the wavelength is detected may be called the wavelength width Δλ.

[0062] This wave train characteristic is expressed by the following formula. Each wave in Figure 3(a) to (e) can be expressed as a plane wave with a different frequency ν ranging from ν0-Δν / 2 to ν0+Δν / 2. Therefore, if we integrate the plane wave over this frequency range, the wave train characteristic is

[0063]

number

[0064] The physical distance ΔL0 from the center to the end of the wave train shown in Figure 3(f) is called the coherence length.

[0065]

number

[0066]

number

[0067] The experimental results for the edge characteristics of the wave train shown in Figure 3(f) are explained below. Figure 4(a) shows the optical system used in the experiment. This optical system is roughly composed of a light source unit 2, a sample mounting unit 36, and a measurement unit 8, with light transmitted between each unit via optical fibers.

[0068] A tungsten halogen lamp HL was used as the light source in the light source unit 2. A concave mirror CM was placed on the opposite side of the light path to increase the efficiency of the light emitted from the halogen lamp HL. In other words, this concave mirror CM reflects the light emitted toward the rear of the halogen lamp HL (left side of the figure) and returns it to the inside of the halogen lamp HL. The light that passes through the inside of the halogen lamp HL then travels toward the front of the halogen lamp HL (right side of the figure).

[0069] A lens L1 with a focal length of 25.4 mm converts the light emitted from the halogen lamp HL into parallel light. This parallel light is then focused onto the entrance surface of the bundle fiber BF by a lens L2 with a focal length of 25.4 mm. The bundle fiber BF contains a bundle of 320 optical fibers, each with a core diameter of 230 μm and an NA of 0.22. An optical property change element 210 is positioned in the middle of the parallel light path between these two lenses L1 and L2.

[0070] The filament that emits light inside the halogen lamp HL has a size of 2mm x 4mm. Therefore, the light emitted from the outermost part inside the filament generates off-axis aberration (coma aberration) in the imaging optical system consisting of two lenses L1 and L2. To eliminate the effects of this coma aberration, an aperture A3 with a diameter of 3mm was placed immediately after the halogen lamp HL.

[0071] In the sample mounting section 36, a lens L3 with a focal length of 50 mm converts the light emitted from the bundle fiber BF into a parallel beam. The parallel beam then enters the sample TS. An aperture A10 with a diameter of 10 mm is placed just before the sample to improve the accuracy and reproducibility of the obtained spectral characteristic data.

[0072] As shown in Figure 4(a), in this experiment, spectral characteristic data is obtained using light transmitted through the sample. A lens L4 with a focal length of 250 mm focuses the light transmitted through the sample onto the entrance surface of a single-core fiber SF (core diameter 600 μm). A near-infrared spectrometer (Hamahoto C11482GA) with a wavelength resolution of 7.5 nm was used as the spectrometer SM. An example of the structure of the optical property change element 210 will be described later using Figure 7B(b).

[0073] The structure of the sample TS used in the experiment is shown in Figure 4(b). That is, a transparent glass plate with a refractive index of "n" and a mechanical thickness of "d = d0 + δd" was placed at the position of the sample TS in the sample mounting section 38. Then, a lens L4 with a focal length of "F" and a pupil radius of "a" focuses the light passing through this transparent glass plate onto the entrance surface of the single-core fiber SF. The inside of the core region on the entrance surface of this single-core fiber SF corresponds to "point P" in Figure 4(b).

[0074] Since the front and back surfaces of the above transparent glass plate are uncoated, approximately 4% of the light that passes through the front and back surfaces of the transparent glass plate is reflected by them. Therefore, the light S0 that travels straight through the transparent glass plate and the light S1 that has been reflected twice by the front and back surfaces interfere at "point P."

[0075] Figure 5 shows the interference state between the straight-traveling light S0 and the light S1 after two reflections. The position of the envelope characteristic S0 of the wave train traveling straight through the transparent glass plate is fixed at a reference position. On the other hand, the function S1 representing the envelope characteristic of the wave train after two reflections is shown as the relative position change when the center wavelength λ0 is changed from 0.9 μm to 1.7 μm.

[0076] The horizontal axis of Figure 5 represents the coherence length ΔL0 expressed by Equation 2 in reference units. Because the mechanical average thickness d0 between the front and back surfaces of the transparent glass plate is a fixed value, the mechanical distance between the center position of the wave train S0 traveling straight through the transparent glass plate and the center position of the wave train S1 after two reflections is kept constant. Now, consider the case where this mechanically constant distance is converted into the reference unit of the coherence length ΔL0. As Equation 2 shows, the coherence length ΔL0 changes in proportion to the square of the center wavelength λ0. Therefore, the relative positions between the two wave trains in Figure 5 appear to change depending on the value of the center wavelength λ0.

[0077] and the overlapping region between both wave trains (shaded area in Figure 5). <s0s1>The area of ​​this corresponds to the size of the optical interference fringes that occur between two wave trains. As shown in Figure 5, when the center wavelength λ0 is 1.7 μm or 1.5 μm, the wave trains overlap. However, when the center wavelength λ0 is 1.1 μm or less, the overlap between the two wave trains is "0," and no interference fringes occur.

[0078] Figure 6A shows the experimental results obtained using the optical system of Figure 4. As mentioned above, the wavelength resolution of the spectrometer SM was 7.5 nm. When calculations were performed assuming the thickness d0 of the transparent glass plate to be 138.40 μm, the measured data and the theoretical calculation results based on existing theory closely matched. However, this region in which the measured data and theoretical calculation results closely matched was limited to wavelengths longer than 1.4 μm. However, at wavelengths shorter than 1.4 μm, a discrepancy was observed between the measured data and the theoretical calculation results based on existing theory, as will be explained in the next section.

[0079] Section 2.2 Relationship between different wave trains and interference characteristics of light Figure 6B(f) shows the wave-train characteristics outside the edge β (around the γ region) calculated using the existing theory. In the existing theory shown in Figure 6B(f), the amplitude of the wave-train decreases and the wave-train disappears as you move away from the center α of the wave-train. In other words, in the existing theory, the wave-train propagates discontinuously through space like pulsed light. Furthermore, the existing theory cannot explain continuously emitted light such as that emitted from a halogen lamp.

[0080] The calculation results based on the existing theory shown in Figure 6B(f) are as follows: A] Wave train amplitudes are also observed in the outer region γ beyond the end β of the wave train. B] The phase is inverted in the α-β region and the outer region (around the γ region) of the train. However, neither [A] nor [B] features were observed in the measurement data in Figure 6A.

[0081] Figure 6B(g) shows a new physical model proposed to solve the problems of the above-mentioned existing theory. As shown in Figure 6B(g), when a paradigm shift (a reversal of the phase angle propagation direction) occurs at the end β of the wave train, the next wave train can be generated and the measurement data in Figure 6A can be explained well. The physical model in which the reversal of the phase angle propagation direction occurs at the end β of the wave train is explained below.

[0082] The envelope characteristics of the wave train near the edge (near the β position in Figure 6B) can be calculated from Equations 1 and 3 as follows:

[0083]

number

[0084]

number

[0085] Then, substituting formula 4 and formula 5 into formula 1, we get

[0086]

number

[0087]

number

[0088]

number

[0089] The upper right-hand side of Equation 8 represents the "leading (occurring first) wave train" near the end. The lower equation of Equation 8 represents the vicinity of the starting end of the "trailing (occurring later) wave train." What is particularly noteworthy is the "reversal of the phase angle propagation direction" that occurs between the upper right-hand side and the lower equation of Equation 8. When this "reversal of the phase angle propagation direction" occurs near the end of the "leading wave train" (near position β in Figure 6B), phase synchronization between the constituent wavelength light begins immediately thereafter. As a result, a "trailing wave train" is generated.

[0090] In electromagnetism, electromagnetic waves propagate through space due to the interaction between oscillating electric and magnetic fields that occur in mutually orthogonal directions. However, near the end of the "leading wave train," the oscillating electric and magnetic field phases become random between wavelengths of light. This random state of the oscillating electric and magnetic fields may form the soil that produces the "phase angle reversal of propagation direction."

[0091] Equation 7 above shows the theoretical condition for the occurrence of the paradigm shift. It is important to note that there is an approximate relationship, not an equality, between the right and left sides of Equation 7. In other words, the "phase angle direction reversal" does not occur at a specific phase value within the "leading wave train," but rather at a "location where the phase is unspecified" within the "leading wave train." As a result, a phase discontinuity (phase asynchrony) occurs between the "leading wave train" and the "following wave train."

[0092] That is, from the above physical model, C) Near the end of the previous wave train, a subsequent wave train is generated (continuous wave train generation). D) The timing of the generation of the following wave train is uncertain, resulting in phase discontinuity (phase asynchrony) between the preceding and following wave trains. The characteristics of the continuous generation of wave trains in [C] were previously unknown and can be derived for the first time from this physical model. On the other hand, the characteristics of [D] are already known, but the reason for their appearance has never been explained until now. This physical model can clearly explain the reason for the characteristics of [D].

[0093] Consider the case where a preceding wave train is shifted and overlapped with a following wave train. If there is phase continuity (phase continuity or phase synchronization) between the preceding and following wave trains, the phase of the combined light obtained by overlapping the preceding and following wave trains is always uniquely determined. However, due to the nature of [D], the amount of phase shift between the preceding and following wave trains is always changing. Therefore, when observed over a specified period of time (when viewed macroscopically in the time direction), no interference between the preceding and following wave trains can be observed. This state is called "incoherence between the preceding and following wave trains" when viewed macroscopically in time.

[0094] Then, in a predetermined period of time, the intensity of the combined light of the preceding wave train and the following wave train becomes equal to the sum of the average intensity of the preceding wave train and the average intensity of the following wave train. In this embodiment, this state is called "intensity addition."

[0095] Section 2.3 Generation of special optical properties using wave-train characteristics FIG. 7A shows a basic optical system arrangement using an optical property conversion element 210 in this embodiment. Specifically, the optical property conversion element 210 splits initial light 200 into multiple light beams 202 to 206. Here, a first optical path 222 within the optical property conversion element 210 forms a first light beam 202 having a first optical property, and a second optical path 224 forms a second light beam 204 having a second optical property. Then, a light combining location 220 combines the first light beam 202 and the second light beam 204 to form a predetermined light beam 230. However, at least a portion between the first optical path 222 and the second optical path 224 is located at a different spatial location. Furthermore, the first optical property of the first light beam 202 and the second optical property of the second light beam 204 are different from each other. This "difference in optical properties" may refer to the "phase discontinuity (phase asynchrony)" between the two beams, as described in the previous section. Alternatively, in relation to the explanation at the end of the previous section, "incoherence" between at least a portion of the first light 202 and at least a portion of the second light 204 may refer to the difference in the optical properties.

[0096] Furthermore, without being limited thereto, a third light 206 having a third optical characteristic may be formed in a third optical path 226. In this case, at least a part of the third optical path 226 may be disposed in a spatial location different from the first optical path 222 and the second optical path 224.

[0097] Here, as a method of arranging at least a part of the first optical path 222, the second optical path 224, and the third optical path 226 at different spatial locations, wavefront division of the initial light 200 may be performed to individually extract each of the light beams 202 to 206. This wavefront division involves arranging each of the regions 212 to 216 at different locations on a light cross section of the incident initial light 200 (a plane obtained by cutting the light beam formed by the initial light 200 with a plane perpendicular to the traveling direction of the initial light 200) or on the wavefront of the initial light 200, and individually extracting each of the light beams 202 to 206.

[0098] The above technical content will be explained again from the perspective of the structure of the optical property conversion element 210 that realizes the optical action. Specifically, the optical property conversion element 210 used in this embodiment includes a first region 212 and a second region 214 that are different from each other. The optical path lengths of the regions 212 and 214 may be different. If the difference between the optical path length of the first light 202 in the first region 212 and the optical path length of the second light 204 in the second region 214 is greater than the aforementioned coherence length ΔL0, a "phase discontinuity (asynchronism)" (different optical properties) occurs between the first light 202 and the second light 204. Furthermore, the spatial structure of the optical property conversion element 210 is such that the first and second light 202 and 204 can be easily combined at the light combining location 220 to form the predetermined light 230.

[0099] A specific example of a spatial structure that makes it easy to combine the first light 202 and the second light 204 to form the predetermined light 230 is a structure in which the incident initial light 200 is wavefront-divided into the individual lights 202 and 204. That is, a spatial structure in which the first region 212 is located in a predetermined region within the cross section of the light beam obtained by cutting the light beam along a plane perpendicular to the traveling direction of the incident initial light 200 may be used. A spatial structure in which the second region 214 is located in another region within the cross section of the light beam may be used. However, this is not limiting, and other methods such as amplitude division or intensity division of the initial light 200 may also be used.

[0100] As another application example, a third region 216 may be further provided in the optical property conversion element 210 , and the third light 206 that has passed through this third region 216 may also be combined with the other light 202 and 204 at the light combining location 220 .

[0101] Figure 7B(b) shows an example of the structure of this optical property conversion element 210. The optical arrangement in Figure 7B(a) is the same as that in Figure 4(a) already described. In this case, the optical property conversion element 210 is located at the position of the parallel light between the two lenses L1 and L2.

[0102] A pair of 2mm and 3mm thick semicircular glass pieces is formed by rotating them 90 degrees and bonding them together. Next, by rotating each pair 45 degrees and bonding them together, an optical property change element is completed that is divided into eight angular sections. The glass thickness of each of the eight divided sections differs by more than 1mm.

[0103] In area A at the bottom left of the optical property modification element 210, the thickness of the optical property modification element (glass) is 0 mm. Therefore, light passing through area A passes directly through an area of ​​the optical property modification element where there is no glass. Starting from area A and proceeding clockwise through areas B, C, and so on, the glass thickness changes sequentially to 2 mm, 4 mm, 7 mm, 10 mm, 8 mm, 6 mm, and 3 mm.

[0104] Light has the characteristic of slowing down when it passes through glass. Therefore, when light passes the same mechanical distance, the optical distance (optical path length) changes between a vacuum and glass. Therefore, the optical path length of the light after passing through the optical property changing element differs depending on which region from region A to region H it passes through. In this embodiment, the individual light beams that pass through each region are called "elements." In other words, different elements have different optical distances (optical path lengths) after passing through the optical property changing element 210.

[0105] 7B(a), all elements are combined in the bundle fiber BF after passing through the optical property change element 210. Here, when the optical path length difference between each element is larger than the coherence length ΔL0 (or larger than twice the coherence length ΔL0), multiple elements that are phase discontinuous / asynchronous (have incoherence) with each other are mixed in the bundle fiber BF.

[0106] The value of this coherence length ΔL0 is uniquely determined by the center wavelength λ0 and wavelength width Δλ, as shown in Equation 2. This center wavelength λ0 is determined by the wavelength range of the light used (or the maximum wavelength of the light used) or the wavelength range of the detection light (or the maximum wavelength of the detection light) used by the measurement unit 8. The wavelength width Δλ is determined by the wavelength width of the light used or the detection performance (for example, wavelength resolution) of the measurement unit 8.

[0107] The optical property change element 210 (glass) is made of BK7, and an anti-reflection coating is applied to the interfaces (front and back) where light enters and leaves. The refractive index of BK7 is represented by n, and the glass thickness in each region of Figure 7B(b) is represented by d. The optical path length within each region can then be calculated as "d(n-1)", and the glass thickness between each region of Figure 7B(b) differs by 1 mm or more.

[0108] Under the measurement conditions for the spectral characteristics described in the next section using FIG. 8, the difference in glass thickness between the above-mentioned regions is greater than the coherence length ΔL0 (or twice the coherence length ΔL0).

[0109] Figure 7C shows the operating principle when the characteristics of the successively generated multiple wave trains described in the previous section are applied to the optical arrangement described in Figure 7A. As already explained in the previous section, it is considered that there is an unsynchronized phase relation 402 between the initial wave trains 400 that are generated one after the other.

[0110] The initial light 200 incident in the form of a continuous generation of the initial wave train 400 shown in Fig. 7C(a) is subjected to wavefront division when passing through the optical property conversion element 210 that manipulates / controls the phase-locking characteristic. Fig. 7C(b) shows the spatial propagation state (wave train state 406) of the first light 202 that passed through the first region 212 in the optical property conversion element 210 of Fig. 7A. Since the first light 202 was extracted as a result of the wavefront division of the initial light 200, the amplitude in Fig. 7C(b) is smaller than the amplitude in Fig. 7C(a).

[0111] Figure 7C(c) shows the spatial propagation state (wave-train state 408) of the second light 204 extracted after passing through the second region 214. The amplitude in Figure 7C(c) is also approximately the same as that in Figure 7C(b), but there is a difference in optical path length between the two. As a result, there is a misalignment between the centers of the wave trains 406 and 408 in Figure 7C(b) and Figure 7C(c).

[0112] As shown in Fig. 7C(a), phase asynchronous (phase discontinuity) 402 occurs between different wave trains 400, and the size of one wave train is given by 2ΔL0 (see Fig. 3(f)). Therefore, if the optical path length difference between the first region 212 and the second region 214 in the optical property conversion element 210 in Fig. 7A is set to 2ΔL0 or more, phase asynchronous 402 occurs at the same position between Fig. 7C(b) and (c).

[0113] 7C(d) shows a situation in which both wave trains 406, 408 are synthesized or combined 410 at the light synthesis location 220 to form the predetermined light 230. When the optical path length difference between them is greater than twice the coherence length 2ΔL0 expressed by Equation 2, the wave trains 406, 408, which are out of phase with each other 402, are synthesized, resulting in an ensemble average effect of intensities 420. This results in an averaging effect (smoothing effect or reduction effect) of the optical noise between the optical noise generated in the first light 202 and the optical noise generated in the second light 204.

[0114] Not limited to the above conditions, for example, even if the optical path length difference between the first region 212 and the second region 214 is greater than the coherence length, elements that are asynchronous (phase discontinuous) 402 are mixed within the predetermined light 230. Therefore, even if the optical path length difference is greater than the coherence length, light intensity averaging 420 occurs in some areas, resulting in the effect of averaging (smoothing or reduction) of optical noise.

[0115] FIG. 7D shows an application example of an embodiment of the structure of the optical property conversion element 210. Semicircular glass pieces with a thickness of 1 mm are rotated by 30 degrees and bonded together, and then semicircular glass pieces with a thickness of 6 mm are bonded together. When viewed from the light propagation direction 348, the piece is divided into 12 equal angular intervals. In this embodiment, the division method of dividing the wavefront cross section of light in the angular direction with the optical axis of the light propagation direction 348 as the reference is called "angular division." Specifically, this refers to the division into regions (wavefront division) along the dashed lines in FIG. 7D(c). The embodiment in FIG. 7D divides the piece into 12 equal angular intervals (angle 12 division). As a result, a difference in glass thickness of 1 mm or more occurs between each of the angle-divided regions.

[0116] FIG. 7D also shows a structure in which cylindrical glass pieces of different diameters are stacked and bonded together. In this embodiment, the division method of dividing the wavefront in the radial direction of the wavefront cross section of light with the optical axis of the light traveling direction 348 as the reference is called "radial division." Specifically, this refers to the region division (wavefront division) along the solid lines in FIG. 7D(c), where the region is divided into regions for each circumference of a different radius. In the embodiment of FIG. 7D, the region is divided into four in the radial direction (4-radius division). The structure of the optical property conversion element 210 shown in FIG. 7D is divided into 12 in the angular direction and 4 in the radial direction. Therefore, the number of divided regions is 48 (12 x 4). However, the number of divisions is not limited to this, and may be set arbitrarily.

[0117] In the embodiment shown in FIG. 7D, the diameter of the boundary line of the radial division is set so that the area of ​​each radially divided region is equal. However, this is not limiting, and the diameter of each cylindrical glass may be set at any interval. The division method may also be changed according to the intensity characteristics of the light passing through (or reflected from) the optical property conversion element 210. For example, consider a case where light with a non-uniform intensity distribution uses the optical property conversion element 210. This light may have an intensity distribution in which the central intensity is high and the intensity decreases at the periphery. In this case, the diameter of the boundary line of the radial division may be set so that the intensity of each element passing through each divided region is approximately equal.

[0118] 7E shows another embodiment of the structure of the optical property conversion element 210. Here, the division method of the optical property conversion element 210 is changed in accordance with the intensity distribution characteristics of the light to be used.

[0119] In Figure 7B(b) or Figure 7D(c), the angle is divided at equal intervals. For example, if the light intensity distribution characteristics are non-uniform in the angular method based on the optical axis, variations in the amount of light will occur for each element that passes through the divided region. An example of this non-uniform light intensity distribution characteristics in the angular method is shown in Figure 7E(a). The shape of the cross section 510 of the laser light emitted from the light-emitting location 502 of the semiconductor laser element 500 is generally elliptical in many cases.

[0120] The angular division interval between the boundary lines in the optical property conversion element 210 shown in FIG. 7E(b) is narrower in the long-axis direction of the laser beam cross section 510. On the other hand, the angular division interval between the boundary lines is wider in the short-axis direction of the laser beam cross section 510. By making the angular division intervals uneven in this way, the amount of variation between the intensities of the elements that have passed through each divided region is reduced. When the intensities of the elements that have passed through each divided region are made approximately equal in this way, the effect of reducing the amount of optical noise in the combined predetermined light 230 (FIG. 7A) (averaging or smoothing the optical noise generated for each element) is improved.

[0121] Section 2.4 Optical noise reduction effect on spectral characteristics FIG. 8(a) shows experimental results regarding the optical noise reduction effect when the optical property conversion element 210 is used. The experiment used the optical system shown in FIG. 7B(a), and a diffuser plate with an average roughness Ra of 2.08 μm was placed as the sample TS. Optical noise is generated from the minute irregularities on the surface of this diffuser plate. The spectral intensity characteristics (measurement wavelength dependence) of the relative intensity ([straight-pass light intensity with diffuser plate placed] ÷ [straight-pass light intensity before diffuser plate placed]) obtained from the spectrometer SM include the above-mentioned optical noise.

[0122] The vertical axis of Fig. 8 represents the standard deviation of the value ([variation] ÷ [average value]) obtained by normalizing the amount of spectral intensity fluctuation (the amount of intensity difference from the average spectral intensity in the wavelength direction) resulting from optical noise generated by the diffuser plate by the average value. The horizontal axis of Fig. 8 represents the number of optical path divisions (number of area divisions) within the optical property conversion element 210. Here, the condition "number of optical path divisions = 1" represents the prior art before the insertion of the optical property conversion element 210.

[0123] As the number of optical path divisions (number of area divisions) increases, the amount of optical noise (standard deviation value) clearly decreases. Each element that passes through each divided area in the optical property change element 210 generates optical noise as it passes through the diffuser. However, the optical path until it reaches the spectrometer SM varies slightly for each element. Therefore, the optical noise characteristics that appear in each element vary slightly from one another. When the intensities of all elements with different optical noise characteristics are added, light intensity averaging 420 (Figure 7C(d)) occurs between the different optical noise characteristics. As a result, the optical noise characteristics are smoothed (the amount of optical noise is reduced based on averaging).

[0124] Fig. 8(b) shows the effect of reducing the amount of optical noise when a diffuser plate with an average surface roughness Ra of 1.51 µm is inserted inside the light source unit 2 (between the optical property conversion element 210 and the condenser lens L2) in Fig. 7B(a). It was confirmed that the optical noise was further reduced by the synergistic effect of the optical property conversion element 210 and the diffuser plate, which corresponds to the phase property conversion member of the wavefront.

[0125] Chapter 3 Example of an embodiment for changing the optical characteristics between two waves emitted from the same light-emitting unit Section 3.1 Basic optical configuration used in this embodiment 9A shows the basic optical configuration used in this embodiment. Two waves, a first light 202 and a second light 204 or 208, are emitted from the same light-emitting unit 470. A predetermined optical member 90 changes the optical characteristics between these two waves. Here, the two waves, the first light 202 and the second light 204 or 208, emitted from the same light-emitting unit 470, may pass through the predetermined optical member 90 or may be reflected by the incident surface 92 of the predetermined optical member 90. In either case, after passing through the predetermined optical member 90, the optical characteristics between the first light 202 and the second light 204 or 208 change.

[0126] In particular, in this embodiment, an incident surface normal 96 that is perpendicular to the incident surface 92 of the predetermined optical member is defined. A first light 202 is incident at an angle θ (θ≠0) that is inclined with respect to this incident surface normal 96. A second light 204 is incident at an angle different from that of the first light 202. Therefore, the first light 202 and the second light 204 travel in mutually different directions before entering the predetermined optical member 90.

[0127] As the second light 208 different from the first light 202, it is possible to define light 208 that travels via a different optical path from the first light 202, rather than light 204 that travels in a different direction from the first light 202. In this case, the traveling direction of the second light 208 may be parallel to that of the first light 202 (i.e., the second light 208 may be incident on the incident surface 92 of the predetermined optical member at the same inclination angle θ as the first light 202 with respect to the incident surface normal 96). However, the second light 208 may also travel in a different direction from the first light 202 and pass through a different optical path from the first light 202.

[0128] When the first light 202 passes through this predetermined optical member 90, after passing through this predetermined optical member 90, the first light 202 passes through an exit surface 94 of the predetermined optical member. At this time, an exit surface normal 98 that is perpendicular to the exit surface 94 of the predetermined optical member is defined. The traveling direction of the first light 202 after passing through the exit surface 94 of the predetermined optical member may have a predetermined inclination angle with respect to the exit surface normal 98, or may be parallel to the exit surface normal 98.

[0129] However, when the first light 202 passes through this specified optical member 90, as shown in Figure 9A, the direction of travel of the second light 204 after passing through the exit surface 94 of the specified optical member must be inclined (non-parallel) to the direction of travel of the first light 202 after passing through. Furthermore, when the first light 202 passes through this predetermined optical member 90, the optical path of the second light 208 after passing through the exit surface 94 of the predetermined optical member needs to be different from the optical path of the first light 202 after passing through. However, the traveling direction of the second light 208 after passing through the exit surface 94 of the predetermined optical member may be parallel to the traveling direction of the first light 202 after passing through.

[0130] The important thing here is, 1. A first light 202 is incident on the incident surface 92 of the predetermined optical member 90 at an angle inclined with respect to the normal 96 to the incident surface of the predetermined optical member 90. 2. Before entering the incident surface 92 of the predetermined optical member, the second light 204 travels in a direction non-parallel to the first light 202, or the second light 208 travels along an optical path different from that of the first light 202.

[0131] In any case, the first light 202 and the second light 204 or 208 after passing through the predetermined optical member 90 are combined (or mixed) at the light combining location 220 to form the predetermined light 230 .

[0132] The basic concept explained in FIG. 9A is summarized below. In the first light 202 and the second light 204 or 208 emitted from the same light-emitting unit 470 and passing through the predetermined optical member 90, An incident surface side normal 96 perpendicular to the incident surface 92 of the predetermined optical member 90 and an exit surface side normal 98 perpendicular to the exit surface 94 of the predetermined optical member 90 are defined, the traveling direction of the first light 202 has an inclination angle with at least either the incident surface side perpendicular 96 or the exit surface side perpendicular 98, The traveling direction of the second light 204 is tilted relative to the traveling direction of the first light 202, or the optical path of the second light 208 within the specified optical member 90 is made different from the optical path of the first light 202, thereby changing the optical characteristics between the first light 202 and the second light 204 or 208.

[0133] The relationship between the predetermined optical member 90 described here and the optical property conversion element 210 described in the previous chapter will be described below. In this embodiment, the optical property conversion element 210 shown in FIG. 7A is included as an example of an embodiment of the predetermined optical member 90. That is, in the description up to the previous chapter, the main function of the optical property conversion element 210 was focused on providing an optical path length difference between the first light 202 and the second light 204 (including the third light 206). If this optical path length difference is set to be equal to or greater than (twice the coherence length ΔL0), the phase continuity between the wave trains in the two can be cut off (phase desynchronization 402). In contrast, the function of the predetermined optical member 92 described using this embodiment encompasses the optical property conversion element 210.

[0134] This predetermined optical member 92 also has different optical characteristics between the first light 202 and the second light 204 (including the third light 206). One example of the form of these "different optical characteristics" is phase asynchronization (phase discontinuity) 402. Another example of the form of "different optical characteristics" is the generation of a mode change (in the waveguide element 110), which will be described later with reference to FIG. 9B.

[0135] In the description of this embodiment, the different optical characteristics provided between the first light 202 and the second light 204 are explained as phase asynchronization (phase discontinuity) 402 and mode change. However, the present invention is not limited to this, and the predetermined optical member 92 may provide any difference in optical characteristics between the first light 202 and the second light 204.

[0136] The positioning of the predetermined optical member 90 within the already explained service providing system 14 and optical device 10 will be described with reference to Fig. 1. In this embodiment, a service providing method 80 corresponds to the overall concept.

[0137] A service providing system 14 is defined as a means for realizing this service providing method 80. The optical device 10 is also included in this service providing system 14. Here, the predetermined light utilization method 82 is positioned as part of the operation of this optical device 10.

[0138] The optical measurement unit 84 constitutes the optical device 10 as a part of the optical device 10. However, the optical measurement unit 84 is also used in a predetermined light utilization method 82. The light source unit 2 is included in this optical measurement unit 84.

[0139] The light source unit 2 is configured with a light emitting unit 470, a predetermined optical member 90, and a light combining location 220. Here, the predetermined optical member 90 and the light combining location manipulate the first light 202 and the second light 204 or 208 emitted from the light emitting unit 470 to form the predetermined light 230.

[0140] Section 3.2 Specific examples of basic optical configurations 9B shows a specific embodiment example in which the predetermined optical member 90 described in FIG. 9A is combined with the light combining location 220. Here, the core region 112 in the waveguide element 110 functions as both the light combining location 220 and the predetermined optical member 90. The specific form of this waveguide element 110 may be any of an optical fiber, an optical waveguide, and an optical guide.

[0141] In Figure 9B, the entrance surface of the waveguide element 110 corresponds to the incident surface 92 of the given optical member in Figure 9A, and similarly, the exit surface of the waveguide element 110 corresponds to the exit surface 94 of the given optical member in Figure 9A.

[0142] There are two types of entrance face shapes for the optical fiber 110: a structure cut perpendicular to the optical axis, and a structure cut at a specified angle. Here, we will provisionally consider an entrance face shape (and exit face shape) cut perpendicular to the optical axis in the optical fiber 110. In this case, an entrance face side normal 96 that is orthogonal to the entrance face 92 of the specified optical member is parallel to the optical axis direction in the optical fiber 110. In this case, an exit face side normal 98 that is orthogonal to the exit face 94 of the specified optical member is also parallel to the optical axis direction in the optical fiber 110.

[0143] Consider a case where the incident angle θ of the first light 202 with respect to the incident surface normal 96 is set to a predetermined value or more, and the first light 202 is allowed to enter the core region 112 in the waveguide element (optical fiber / optical waveguide / optical guide) 110. In this case, as shown in FIG. 9B , the first light 202 is reflected at the interface between the core region 112 and the cladding region 114. Since the length of the actual waveguide element (optical fiber / optical waveguide / optical guide) 110 is sufficiently long, reflection at this interface is repeated many times. As a result, the first light 202 forms a higher-order mode other than the fundamental mode (for example, the TE2 mode, which will be described later in FIG. 16C(b)) in the core region.

[0144] On the other hand, consider the case where second light 204 is incident from a direction substantially parallel to the incident surface normal 96 and is incident on the center of the core region 112. In this case, the second light 204 travels straight through the center of the core region 112. Compared to the first light 202, the number of times that the second light 204 is reflected at the interface between the core region 112 and the cladding region 114 is overwhelmingly smaller. As a result, the second light 204 forms a fundamental mode (for example, the TE1 mode, which will be described later with reference to FIG. 16C(a)) in the core region.

[0145] Like this 1. The first light 202 is incident on the incident surface 92 of the predetermined optical member 90 at an angle inclined with respect to the normal 96 of the incident surface of the predetermined optical member 90. 2. Before being incident on the incident surface 92 of the predetermined optical member, the second light 204 travels in a direction non-parallel to the first light 202. By devising an optical arrangement like this, a "mode difference in the core region 112" occurs, which corresponds to the different optical characteristics (optical characteristics that have changed from each other) between the first light 202 and the second light 204. A method for reducing speckle noise (optical noise) by utilizing the mode difference between these two waves (first light 202 and second light 204) will be described later in Section 5.3.

[0146] 9B, the angle ζ formed by the first light 202 emitted from the waveguide element (optical fiber / optical waveguide / light guide) and the emission surface normal 98 is also large. When confirmed through actual experiments, the emission pattern (far-field pattern) of the first light 202 from the waveguide element (optical fiber / optical waveguide / light guide) exhibits a "doughnut-shaped pattern" (a pattern in which the light intensity decreases in an area close to the optical axis center and increases in an area away from the optical axis center).

[0147] Similarly, the light intensity distribution of the second light 204 emitted from the waveguide element (optical fiber / optical waveguide / optical guide) increases as it approaches the exit surface normal 98 (the light intensity emitted in a direction parallel to the exit surface normal 98 is maximum).

[0148] Fig. 9B shows a specific embodiment example in which the traveling direction of second light 204 is tilted with respect to the traveling direction of first light 202 before incidence on incident surface 92 of predetermined optical member 90 in Fig. 9A to change the optical characteristics therebetween. As another embodiment of Fig. 9A, Fig. 9C shows a specific embodiment example in which second light passes through an optical path different from that of first light 202 to change the optical characteristics therebetween.

[0149] The embodiment of the predetermined optical member 90 shown in Figure 9C is a transparent parallel plate having a light-reflecting surface 118 on a portion thereof. An anti-reflection film is formed on the surface of this transparent parallel plate other than the light-reflecting surface 118 (incident surface 92 of the predetermined optical member). In the predetermined optical member 90 shown in Figure 9C, the front surface (front surface) corresponds to the incident surface 92 of the predetermined optical member, and the back surface (rear surface) corresponds to the exit surface 94 of the predetermined optical member.

[0150] The collimating lens 318 converts the divergent light emitted from the light-emitting unit 470 into parallel light. When a semiconductor laser element 500 is used as the light-emitting unit 470, the cross section 510 of the parallel laser light has an elliptical shape, as shown in FIG. 7E. In the embodiment shown in FIG. 9C, the minor axis direction 88 within this ellipse is parallel to the paper surface. Therefore, the major axis direction within this ellipse is perpendicular to the paper surface.

[0151] At this time, the electric field oscillation direction within the collimated laser beam coincides with the minor axis direction 88. A predetermined optical element 90, composed of a transparent parallel plate, is positioned at an angle relative to the direction of travel of the collimated laser beam. The predetermined optical element 90 is tilted along a plane (a plane including the paper surface) that contains the electric field oscillation direction within the laser beam. Therefore, the tilt directions of the incident surface 92 and the exit surface 94 of the predetermined optical element are in a P-wave (parallel wave) relationship with respect to the electric field oscillation direction within the laser beam. It is generally known that the incident surface 92 and the exit surface 94 have high optical transmittance for P-waves. Therefore, tilting the incident surface 92 or the exit surface 94 of the predetermined optical element in a direction that results in a P-wave with respect to the electric field oscillation direction within the laser beam effectively increases the transmission efficiency of light passing through the incident surface 92 or the exit surface 94.

[0152] The direction of travel of the parallel light after passing through collimating lens 318 is inclined at an angle θ (θ≠0) with respect to a normal 96 to the incident surface of the predetermined optical member. When the incident surface 92 and the exit surface 94 of the predetermined optical member are parallel to each other, the angle ζ between the direction of travel of the light leaving the exit surface and a normal 98 to the exit surface coincides with θ (ζ=θ≠0). In this embodiment, the exit surface 94 of the predetermined optical member 90 has a specific light reflectance. Then, a portion of the light transmitted through the incident surface 92 of the predetermined optical member passes through the exit surface 94 of the predetermined optical member, and the remaining light is reflected by the exit surface 94. In the embodiment of FIG. 9C , the light that has passed through the exit surface 94 of the predetermined optical member is treated as first light 202.

[0153] The light reflected by this exit surface 94 is reflected again by the light-reflecting surface 118, and a portion of this reflected light passes through the exit surface 94 of the predetermined optical member. Here, the light that passes through this exit surface 94 is treated as second light 208. As is clear from FIG. 9C , this second light 208 passes through a different optical path from the first light 202 described above. Furthermore, the optical path length of the second light 208 within the predetermined optical member 90 is different from the optical path length of the first light 202. If the difference in optical path length between the two is set to be greater than (twice the) coherence length ΔL0 shown in Equation 2, the phase continuity between the first light 202 and the second light 208 is interrupted (a phase asynchronism 402 occurs). In other words, from the perspective of phase continuity (phase synchronism), the optical characteristics between the first light 202 and the second light 208 change.

[0154] The shape of the laser beam cross section 510 of each of the first beam 202 and the second beam 208 immediately after passing through the exit surface 94 of this predetermined optical member 90 is elliptical. However, the first beam 202, the second beam 208, and the third beam 206 immediately after passing through the exit surface 94 are aligned in the minor axis direction 88. As a result, the effect of correcting the elliptical shape of the laser beam cross section 510 is achieved. In other words, tilting the predetermined optical member 90 within a plane including the minor axis direction 88 of the laser beam cross section 510 emitted from the semiconductor laser element 500 (light-emitting portion 470) has the effect of correcting the elliptical shape of the laser beam cross section 510.

[0155] At the end of Section 3.2, the optical arrangement features of this embodiment will be summarized. As shown in Figure 9A, a first light 202 is incident on a predetermined optical member 90 from a direction at an inclination angle θ (θ ≠ 0) with respect to a normal (incident surface normal 96) perpendicular to the incident surface 92. The predetermined optical member 90 changes the optical characteristics between the first light 202 and the second light 204 or 208 after passing through the predetermined optical member 90.

[0156] In the embodiment shown in Fig. 9B, the incident direction of the second light 204 is different from the incident direction of the first light 202. The difference in optical properties between the first light 202 and the second light 204 corresponds to the "difference in optical propagation mode within the core region 112."

[0157] In the embodiment example of Figure 9C, the optical path of the second light 208 is different from the optical path of the first light 202. The difference in optical properties between the first light 202 and the second light 208 corresponds to "phase asynchrony 402 (disruption of phase continuity)" between the two.

[0158] The optical characteristics that change between the first light 202 and the second light 204 or 208 after passing through the specified optical member 90 are not limited to those described above, and may be any difference in optical characteristics or any change (discontinuity) in optical characteristics.

[0159] Section 3.3 Other Optical Configuration Examples Other specific examples of specific embodiments of the given optical element 90 shown in FIG. 9A are described in Section 3.3. In various specific examples of specific embodiments described in Section 3.3, A) The incident surface normal 96 or the exit surface normal 98 of the predetermined optical member 90 is inclined with respect to the incident direction of the first light 202, B) The incident surface 92 or the exit surface 94 of the predetermined optical member 90 has a discontinuous surface (a microscopic step shape).

[0160] 9D(a) shows an example of a conventional optical system for correcting the elliptical shape of a cross section 510 of laser light emitted from a semiconductor laser element 500. To clarify the effect of (B) above, the difference between FIG. 9D(a) and (B) above will be explained below.

[0161] The collimating lens or cylindrical lens 120 in Figure 9D(a) converts the divergent light (divergent laser light) emitted from the light-emitting unit 470 (semiconductor laser element 500) into parallel light. In this parallel light state, the equiphase surface 128 of the light is flat. Furthermore, the cross section 510 of the laser light in this parallel light state often has an elliptical shape (see Figure 7E(a)). Here, the minor axis direction 88 of the elliptical shape coincides with the paper surface. The wedge-shaped prism 130 elongates the minor axis direction of the parallel light, correcting the elliptical shape and converting it into an approximately circular shape.

[0162] The direction of travel of the collimated light immediately after passing through the collimating lens or cylindrical lens 120 is inclined with respect to the normal 96 to the incident surface of the wedge prism 130. Therefore, the optical arrangement shown in Figure 9D(a) satisfies the characteristic (A) described above. However, what is important is that the equiphase surface 128 in the collimated light after passing through the wedge prism 130 forms a uniformly flat surface throughout. The optical noise reduction method described in Section 2.3 divides the equiphase surface 128 in the collimated light into multiple regions and changes the optical path length difference between each region to be equal to or greater than the coherence length ΔL0 (or twice that length). However, when the equiphase surface 128 in the collimated light after passing through the wedge prism 130 forms a uniformly flat surface throughout, as shown in Figure 9D(a), the optical noise reduction effect described in Section 2.3 is not achieved.

[0163] 9D(b), compared to FIG. 9D(a), a discontinuous surface is formed by providing minute steps on the exit surface 94 of the predetermined optical member 92. This breaks up the equiphase surface 128 of the light that has passed through the exit surface 94 of the predetermined optical member 92, thereby achieving the optical noise reduction effect described in section 2.3.

[0164] In Figure 9D(b), the exit surface 94 of the predetermined optical member 92 is a discontinuous surface. However, this is not limiting, and the entrance surface 92 of the predetermined optical member 92 may also be a discontinuous surface. Making at least a portion of the entrance surface 92 and exit surface 94 of this predetermined optical member 92 a discontinuous surface with a fine step represents the content of (B) above. This makes it possible to achieve the optical noise reduction effect described in Section 2.3.

[0165] Next, the relationship between the various specific individual embodiments described in Section 3.3, including Figure 9D(b), and the content described in Section 3.1 using Figure 9A will be described. Of the light emitted from the same light-emitting unit 470 and passing through the collimating lens or cylindrical lens 120, the light that passes through the center of the collimating lens or cylindrical lens 120 corresponds to first light 202. Also, the light that passes through the peripheral part of the collimating lens or cylindrical lens 120 corresponds to second light 204. Because the first light 202 and the second light 204 pass through different locations within the collimating lens or cylindrical lens 120, the optical paths of the first light 202 and the second light 204 are different.

[0166] The traveling direction of the first light 202 is inclined at an angle θ (θ≠0) with respect to an incident surface normal 96 that is orthogonal to the incident surface 92 of the predetermined optical member 90. By adopting the optical arrangement described in (A) above, the optical noise reduction effect described in Section 2.3 can be achieved.

[0167] A flat equiphase surface 128 is formed within the parallel light immediately after passing through the collimating lens or cylindrical lens 120. Among these, the equiphase surface 128 of the second light 204 reaches the incident surface 92 of the predetermined optical member first. The equiphase surface 128 of the first light 202 then reaches the incident surface 92 of the predetermined optical member with a delay. In this way, by tilting the traveling direction of the first light 202 by an angle θ (θ≠0) with respect to the incident surface side normal 96 of the predetermined optical member 90, the optical path length until reaching the predetermined optical member 90 changes between different optical paths.

[0168] In order to achieve the optical noise reduction effect described in section 2.3, it is necessary to set this optical path length difference to be greater than (twice the value of) the coherence length ΔL0. To satisfy this condition, when the beam size of the light incident on this predetermined optical member 90 is D,

[0169]

number

[0170]

number

[0171] The beam size D of the light incident on the predetermined optical member 90 may be set as an effective beam diameter. In other words, the maximum diameter of light that can pass through the collimator lens or cylindrical lens 120 is considered to be the effective beam diameter. However, without being limited to this, the beam size D of the light may be considered to be the width (half-value width or half-value diameter) of a region where the intensity is half the maximum intensity of the central portion in the intensity distribution of the light incident on the predetermined optical member 90. Alternatively, the beam size D of the light may be the width (half-value width or half-value diameter) of a region where the intensity is half the maximum intensity of the central portion in the intensity distribution of the light incident on the predetermined optical member 90. -2 The width of the region where the intensity is -2 width or e -2 diameter) can be considered as the beam size D of the light.

[0172] When the collimating lens or cylindrical lens 120 converts the light emitted from the light emitting unit 470 into parallel light, there is a relationship D=2FNA between the focal length F of this collimating lens or cylindrical lens 120 and the NA (numeric aperture) value. However, here, the effective light beam diameter of the collimating lens or cylindrical lens 120 is considered to be the beam size D of the light. Therefore, by utilizing this relationship, the above formulas 9 and 10 can be expressed as

[0173]

number

[0174]

number

[0175] When a semiconductor laser element 500 is used as the light-emitting unit 470, the cross section 510 of the laser beam emitted therefrom has an elliptical shape (see FIG. 7E(a)). The minor axis direction 88 of this ellipse may coincide with the electric field vibration direction of the laser beam. Therefore, when the predetermined optical member 90 is tilted in a plane including the minor axis direction 88 (the paper surface direction in FIG. 9D(b)), the tilt direction of the incident surface 92 of the predetermined optical member 90 becomes the P-wave incident direction of the laser beam. When the P-wave is incident, the predetermined optical member 90 has an optical characteristic of increasing the light transmittance at the interface (incident surface 92). Therefore, tilting the predetermined optical member 90 in a plane including the minor axis direction 88 has the effect of increasing the utilization efficiency of the light transmitted through the predetermined optical member 90. At the same time, it also has the effect of correcting the ellipse of the laser beam cross section 510 (making the ellipse closer to a circle).

[0176] 9D(a) shows a situation in which optical noise cannot be reduced if the exit surface of the wedge prism 130 is made flat, because the equiphase surface 128 of the exiting light becomes flat everywhere within the laser beam cross section 510. In order to achieve the effect of reducing optical noise, in FIG. 9D, the exit surface of the predetermined optical member 90 is made discontinuous (with fine steps formed), and the equiphase surface 128 of the exiting light is wavefront split. In other words, the laser beam cross section 510 is wavefront split for each flat surface within the steps.

[0177] 9D(b), a fine step structure is provided on the exit surface 94 of the predetermined optical member 90. However, this is not limiting, and a fine step structure may also be provided on the entrance surface 92 side of the predetermined optical member 90. A predetermined optical member 90 having fine steps on the exit surface 94 or entrance surface 92 may be called a multi-segment Fresnel prism 140.

[0178] The number of planes per step in the laser beam cross section 510 corresponds to the number of wavefront divisions. Therefore, as the value of the distance P between adjacent steps decreases, the number of wavefront divisions increases. Mechanical cutting techniques can be used to form fine steps in the exit surface 94 or entrance surface 92 of the specified optical component 90. This makes it relatively easy to form steps with a small distance P between adjacent steps, significantly increasing the number of wavefront divisions. As shown in Figure 8 or Figure 17B (details will be described later), the optical noise reduction effect improves as the number of wavefront divisions increases. In other words, providing a fine step structure on the entrance or exit surface of the specified optical component produces the effect of significantly reducing optical noise in a relatively easy manner.

[0179] The light intensity distribution within the beam size D of the light incident on the specified optical member 90 is rarely uniform. The light intensity is greatest near the center and often decreases as the light approaches the periphery. Therefore, if the distance P between adjacent steps is made uniform throughout, the light intensity of the divided light extracted near the center will be high. For this reason, the value of the distance P between adjacent steps may be changed from location to location in accordance with the light intensity distribution incident on the specified optical member 90. Specifically, the value of the distance P between adjacent steps may be made small near the center and gradually increased as the distance P approaches the periphery. By setting it in this manner, the light intensity of each divided light (element) divided and extracted for each step will be made uniform, improving the optical noise reduction effect.

[0180] When the incident surface 92 or the exit surface 94 has a fine step structure in this way, the optical noise reduction effect is improved by providing a phase asynchronism 402 (phase discontinuity) relationship between the wavefront division light (elements) extracted between adjacent steps. The conditions for satisfying this characteristic are as follows:

[0181]

number

[0182]

number

[0183] The value of Pmax described in the above formula is determined by the conditions of the mounting dimensions of the light source unit 2, the optical measurement unit 84, and the optical device 10. Therefore, the value of Pmax should be set to 10 m or 1 m, preferably 10 cm.

[0184] By tilting the predetermined optical member 90 (either the incident surface 92 or the exit surface 94) with respect to the traveling direction of the first light 202 and setting the conditions so as to satisfy any one of the formulas 9 to 14, a difference in optical path length occurs due to the difference in the optical path, and optical noise can be effectively reduced. Therefore, by utilizing the specific individual embodiment described in Section 3.3 or the basic optical arrangement described in Section 3.1, it is possible to easily reduce the size of the optical system within the light source unit 2. Furthermore, since the number of optical components used can be significantly reduced, it is also possible to reduce the price of the light source unit 2 or the optical device 10 as a whole.

[0185] When the incident surface 92 or the exit surface 94 has a fine step structure, the exit surface normal 98 or the incident surface normal 96 is defined as "a perpendicular line to each plane formed between adjacent finely divided steps." For example, in a Fresnel lens, the planes of each step are inclined relative to each other. Therefore, in this case, the angle of the exit surface normal 98 or the incident surface normal 96 differs for each step.

[0186] The exit surface normal 98 to the first light 202 means a normal that is perpendicular to the minute plane through which the first light 202 passes. This allows the angle ζ to be defined between the first light 202 that has exited the predetermined optical member 90 and the exit surface normal 98. Similarly, if a minute step structure is provided within the entrance surface 92 of the predetermined optical member, the normal to each minute plane region within the step boundary may be defined as the entrance surface normal 96.

[0187] As will be described later in Section 5.1 using Figure 13, a slight tilt in the light propagation direction of each element that is out of phase with one another (phase discontinuity) 402 can improve the speckle noise reduction effect. Therefore, the tilt amount of the minute flat areas within the step boundary (the corresponding angle of the exit surface normal 98 or the entrance surface normal 96) can be individually changed. As a result, the propagation direction of the light passing through each minute flat area changes after passing through. In Figure 9D(b), the propagation direction of the first light 202 after passing through the exit surface 94 of the specified optical member 90 is indicated by a solid arrow, and the propagation direction of the second light 204 is indicated by a dashed arrow. The propagation directions of the two light beams are different.

[0188] When creating this fine step structure by mechanical cutting, it is easy to do so by slightly tilting the cutting angle of the tool for each fine flat area. Therefore, by providing an inclination between the fine flat areas within the step boundary, it is possible to effectively reduce speckle noise in a relatively simple manner.

[0189] In the fine step structure shown in Figure 9D(b), the spaces between the steps (the areas between the boundary lines of the steps) are flat. However, this is not a limitation, and the spaces between the steps may be curved, as in a Fresnel lens. Furthermore, instead of having a fine step structure, a discontinuous curved surface (variation in curvature depending on location or change depending on the location of the spherical center point) may be provided, as in a fly's eye lens, which will be described later. Furthermore, a "fine non-uniform characteristic surface," which expands on the concept of the discontinuous curved surface, may be provided. In this case, the boundary lines where the curved surface is discontinuous or the boundary lines between uniform characteristic surfaces are specified, and the spacing between the boundary lines is redefined as the distance P between adjacent regions, and the optical arrangement may be such that the condition of Equation 13 or Equation 14 is satisfied.

[0190] FIG. 9E illustrates the difference in wavefront (phase surface) characteristics between light passing through a conventional spherical lens or aspherical lens and light passing through a Fresnel lens or fly's eye lens 142.

[0191] 9E(a) shows an example in which the imaging lens 144 is configured using a spherical lens or an aspherical lens. The continuity of the equiphase surface 128 is maintained from the light-emitting portion 470 to the imaging position (position α). Furthermore, since the equiphase surface 128 has the same phase everywhere, the phase asynchrony 402 phenomenon does not occur.

[0192] FIG. 9E(b) shows an example of an imaging optical system configured with a Fresnel lens or fly's eye lens 142. This fly's eye lens has a structure in which multiple spherical or aspherical lenses are arranged on a two-dimensional plane and cemented together. Therefore, discontinuity in the curved surface (curvature) occurs between adjacent spherical or aspherical lenses. Even when a Fresnel lens or fly's eye lens 142 is used, the light emitted from the light emitting unit 470 is imaged at position α.

[0193] However, Fresnel lenses and fly's eye lenses 142 have minute steps or curved discontinuities on the light entrance surface or light exit surface, which causes division of the equal phase surfaces 128 in the light emitted from the Fresnel lens or fly's eye lens 142. When the difference in optical path length between the divided equal phase surfaces 128 exceeds the coherence length ΔL0 (or twice the coherence length), phase asynchrony (phase discontinuity) 402 occurs between the divided equal phase surfaces 128.

[0194] 9F shows a Fresnel lens or Fresnel lens 142 arranged at an angle as the predetermined optical member 90. The incident side normal 96 of the predetermined optical member 90 is tilted by an angle θ with respect to the traveling direction of the first light 202 immediately before it reaches the incident surface 92 of the predetermined optical member 90. By tilting the predetermined optical member 90 in this way, the optical path length from the light emitting unit 470 to the incident surface 92 of the predetermined optical member 90 is changed for each optical path. The predetermined optical member 90 is optically arranged so that the difference in optical path length between the light (first light 202, second light 204, and third light 206) passing through different optical paths exceeds the coherence length ΔL0 (or twice the coherence length).

[0195] Instead of using a collimating lens or cylindrical lens 120 to collimate the light incident on the predetermined optical member 90 as shown in Figure 9F(a), the diverging light may be incident on the predetermined optical member 90 as it is, as shown in Figure 9F(b). This eliminates the need for the collimating lens or cylindrical lens 120, reducing the number of parts. This also has the effect of making the entire optical system smaller and less expensive.

[0196] The waveguide element (optical fiber / optical waveguide / light guide) 110 in Fig. 9F(a) corresponds to the light combining location 220 in Fig. 9A. Instead of generating the predetermined light 230 by combining different elements using light propagation in the waveguide element (optical fiber / optical waveguide / light guide) 110, a measurement object 22 may be used as in Fig. 9F(b).

[0197] Near-infrared light in the wavelength range of 0.8 μm to 2.5 μm is known to penetrate deep into living organisms. Because living organisms have a complex structure (a complex and minute refractive index distribution), the near-infrared light that penetrates is scattered within the organism. During this scattering process, the light undergoes a photosynthetic process between different elements that are in a phase-synchronized relationship with each other.

[0198] 9G shows an embodiment example in which a light-reflecting optical member is used as the predetermined optical member 90, which is arranged at an angle with respect to the traveling direction of the first light 202 immediately before incidence. As a specific embodiment example of this light-reflecting optical member, in FIG. 9G, a multi-segmented light-reflecting element or Fresnel-type reflector 148 is used. However, it is not limited to this, and it is also possible to use an optical member 90 that has light-reflecting properties and includes any structure in the light-reflecting surface that "constitutes a surface with finely non-uniform characteristics," such as a "fine step structure," a "finely divided curved surface structure," or "discontinuous curvature radii or inconsistencies in the centers of curved surfaces."

[0199] Here, when a multi-segment light-reflecting element 148 is used as the light-reflecting optical member 90, the distance P between adjacent steps can be specified. When a light-reflecting surface on which other "fine non-uniform characteristic surfaces" are formed is used, the spacing between the boundary lines where the uniform characteristic surface (including curved surfaces) changes can be specified as the distance P between adjacent regions. In either case, when the optical arrangement is set so as to satisfy the conditions of either Formula 13 or Formula 14, the effect of reducing optical noise in the reflected light from the specified optical member 90 is achieved.

[0200] Furthermore, the value of P may be changed between different locations on the predetermined optical member 90 depending on the light intensity distribution of the light incident on the predetermined optical member 90. For example, the light intensity distribution of the incident light may be such that the light intensity is greatest near the center and decreases in the periphery. In this case, the distance P between adjacent steps (distance between adjacent regions) may be narrowed near the center of the incident light and widened in the periphery of the incident light. This makes the light intensity between the light (elements) reflected in each region more uniform, improving the optical noise reduction effect.

[0201] In Figure 9G, an Fθ lens or collimating lens 324 is used as an optical element that changes the divergence of the divergent emitted light from the light-emitting unit 470. An Fθ lens has the property of focusing parallel light incident at an angle θ at a different position on the focal plane. This Fθ lens is named after its property of focusing light at a position shifted by Fθ relative to its focal length F. A collimating lens basically has the same property, but coma aberration increases as the Fθ value (image height) increases. Therefore, in optical systems where the Fθ value (image height) becomes small, a collimating lens can be used instead of an Fθ lens.

[0202] Here too, the minute flat surface within the boundary line of the step is defined as the incident surface 92 of the specified optical element. The perpendicular line perpendicular to this plane corresponds to the incident surface side perpendicular line 96. In the embodiment shown here, all of the incident surface side perpendicular lines 96 within the specified optical element 90 are parallel to one another (all of the finely divided incident surfaces 92 of the specified optical element are parallel to one another).

[0203] An inclination angle θ is formed between the traveling direction of the first light 202 immediately before it enters the predetermined optical element 90 and the incident surface normal 96. If θ = 0, the light reflected by the incident surface 92 of the predetermined optical element returns to the light-emitting point within the light-emitting unit 470. Therefore, in this embodiment, by setting θ ≠ 0, the light reflected by the incident surface 92 of the predetermined optical element is focused at a position different from the light-emitting unit 470. The entrance surface (within the core region 112) of the waveguide element (optical fiber / optical waveguide / light guide) 110 is then positioned at this focused position. The light passes through the waveguide element (optical fiber / optical waveguide / light guide) 110 and is combined between different elements. This corresponds to the light combining location 220 in Figure 9A within the waveguide element (optical fiber / optical waveguide / light guide) 110.

[0204] A fine step structure is formed on the light incident surface 92 (light reflecting surface) of the predetermined optical member 90. The plane (or curved surface) obtained by macroscopically averaging this fine step structure is defined as the macroscopic light incident surface 122 of the predetermined optical member. As an alternative method for defining the macroscopic light incident surface 122 of the predetermined optical member, it may be defined as an upper or lower envelope surface of the fine step structure. Then, a perpendicular line perpendicular to the macroscopic light incident surface 122 of the predetermined optical member is defined as a normal line 126 to the macroscopic light incident surface. Then, the angle ξ between the traveling direction of the first light 202 immediately before it is incident on the predetermined optical member 90 and the normal 126 of this macroscopic incident surface can be defined.

[0205] The optical path difference between the first light 202 and the second light 204 in the optical system of FIG. 9G occurs within the optical path from the light emitting unit 470 to the waveguide element (optical fiber / optical waveguide / light guide) 110 (corresponding to the light combining location 220 in FIG. 9A). In particular, when a reflective optical element 90 (multi-segment optical reflecting element (Fresnel reflector) 148) is used, the optical path difference occurs over twice the optical path before and after reflection, i.e., the forward and backward paths. Therefore, when a reflective optical element 90 is used, an optical path difference twice the mechanical arrangement dimension is obtained. When a predetermined optical path difference is set by tilting the reflective optical element 90 with respect to the traveling direction of the first light 202, using a reflective optical element 90 has the effect of enabling the optical system to be made more compact.

[0206] If the value of this angle ξ is set large, the optical path length from the light emitting unit 470 to the macroscopic incident surface 126 of the predetermined optical member 90 will vary greatly depending on the optical path.

[0207]

number

[0208]

number

[0209] Incidentally, the light cross-sectional size D immediately before incidence on the predetermined optical member 90 may be defined as the effective beam diameter of the light emitted from the light-emitting unit 470 that can pass through the Fθ lens or the collimator lens 324. However, without being limited to this, the light cross-sectional size D may be considered to be the width (half-value width or half-value diameter) of the area where the intensity of the light emitted from the light-emitting unit 470 decreases to half of the maximum intensity. Another way to think about it is to consider the width of the area where the intensity of the light emitted from the light-emitting unit 470 decreases to half of the maximum intensity. -2 The width of the area where the intensity of -2 width or e -2 The diameter of the beam (value) may be considered as the beam cross section size D.

[0210] The focal length of the Fθ lens or collimator lens 324 is represented by F. The relationship D=2FNA holds between the light cross-sectional size D (effective beam diameter) of the parallel light immediately before it enters the predetermined optical member 90 and the NA value of the Fθ lens or collimator lens 324. Therefore, using this relationship, the above formulas 15 and 16 can be expressed as follows:

[0211]

number

[0212]

number

[0213] Next, we will explain the conditions under which the optical coherence between the reflected light (elements) of each adjacent step (adjacent region) is reduced, and the optical noise generated in the predetermined light 230 combined in the waveguide element (optical fiber / optical waveguide / light guide) 110 is reduced. When the optical path length difference between the reflected light (elements) of each adjacent step (adjacent region) is ΔL0 / 2 or more, the optical coherence between them is reduced. Therefore, the value of the distance P between adjacent steps (distance between adjacent regions) is

[0214]

number

[0215]

number

[0216] When a semiconductor laser element 500 is used as the light-emitting unit 470, the cross section 510 of the emitted laser light often has an elliptical shape. The reflective optical member 90 may be tilted in a direction along a plane (the plane of the paper in FIG. 9G) that includes the major axis direction 78 of this elliptical shape. This arrangement not only achieves a compact optical system overall, but also increases the number of wavefront divisions (due to the number of steps) in the major axis direction. As a result, the optical noise reduction effect is improved (see FIG. 8).

[0217] In the embodiment shown in FIG. 9G, an Fθ lens or a collimating lens 324 is used to cause parallel light to enter the predetermined optical member 90. However, this is not a limitation, and an optical system that does not use an Fθ lens or a collimating lens 324 may also be used. In this case, a Fresnel concave mirror (a multi-segment concave mirror) or a concave Fresnel elliptical mirror (a multi-segment elliptical mirror) is used as the light-reflecting surface of the predetermined optical member 90. When an Fθ lens or a collimating lens 324 is not used, divergent light emitted from the light-emitting unit 470 directly enters the reflective predetermined optical member 90. Therefore, as long as the divergent light directly incident on the reflective predetermined optical member 90 can be focused to a single point (such as the entrance of the waveguide element 110) after reflection, the shape of the reflective surface of the reflective predetermined optical member 90 is not limited to the above and may be arbitrarily set.

[0218] In the embodiment shown in Figure 9G, the tilt direction of the microscopic incident surface 92 of the specified optical member is made to coincide with the tilt direction of the macroscopic incident surface 122 of the specified optical member. This has the effect of increasing the light utilization efficiency of the multi-segment light reflecting element 148 (specified optical member 90). The condition for matching the tilt directions of both can be expressed mathematically as ξ x θ ≥ 0.

[0219] Figure 9H is a diagram illustrating the effect of the above conditions. Conditions that deviate from the above conditions can be expressed mathematically as ξ × θ < 0. Under these conditions, the side surfaces of the step are exposed in the direction of propagation of the incident light, as shown in Figure 9H. Reflected light from these exposed side surfaces of the step becomes stray light component 146, reducing the utilization efficiency of light returning to the waveguide element (optical fiber / optical waveguide / optical guide) 110.

[0220] FIG. 9I shows an example of an application of FIG. 9G. Therefore, the content explained using FIG. 9G is basically valid as is. When a semiconductor laser element 500 is used as the light-emitting unit 470, speckle noise is likely to occur. However, if the irradiation direction of each element that is in a phase-asynchronous 402 relationship (that does not interfere with each other) toward the measurement object 22 is slightly shifted, speckle noise can be significantly reduced. Details will be explained in Section 5.1 using FIG. 13.

[0221] Therefore, the tilt amounts θ1 to θ3 are slightly shifted between the incident surfaces 92-1 to 92-3 of the respective predetermined optical members separated by steps. The angle between an incident surface-side perpendicular 96-1, which is perpendicular to the incident surface 92-1 of the predetermined optical member onto which the first light 202 is incident, and the traveling direction of the first light 202 immediately before incidence is defined as θ1. Similarly, the angle between an incident surface-side perpendicular 96-2, which is perpendicular to the incident surface 92-2 of the predetermined optical member onto which the second light 204 is incident, and the traveling direction of the second light 204 immediately before incidence is defined as θ2. The angle between an incident surface-side perpendicular 96-3, which is perpendicular to the incident surface 92-3 of the predetermined optical member onto which the third light 206 is incident, and the traveling direction of the third light 206 immediately before incidence is defined as θ3. The traveling directions of the first light 202, the second light 204, and the third light 206 immediately before incidence are parallel to one another. Therefore, when the incident surfaces 92-1, 92-2, and 92-3 are inclined, the relationship becomes, for example, θ1<θ2<θ3 or θ1>θ2>θ3.

[0222] A transmissive or reflective diffuser 460 is placed on the focal plane of the Fθ lens or collimator lens 324. The incident surfaces 92-1, 92-2, and 92-3 of the predetermined optical member are tilted in accordance with the above conditions. Then, the first light 202 is reflected by the incident surface 92-1 of the predetermined optical member and then focused at a position ρ1 on the diffuser 460. The second light 204 is reflected by the incident surface 92-2 of the predetermined optical member and then focused at a position ρ2 on the diffuser 460, and the third light 206 is reflected by the incident surface 92-3 of the predetermined optical member and then focused at a position ρ3 on the diffuser 460.

[0223] 9I uses a Koehler illumination system to irradiate light onto the measurement object 22. Therefore, the light beams (elements) that pass through the collimating lens or imaging lens 450 via different focusing points ρ1, ρ2, and ρ3 travel in slightly different directions and are combined together to irradiate the measurement object 22. Furthermore, the light beams (elements) mix together (further combining is promoted) due to the action of a diffuser 460 arranged on the focusing surface.

[0224] A reflecting surface 254 that reflects a portion of the light is installed just before the diffusing plate 460 arranged on the light collecting surface, and the light reflected here is collected in the light detecting element 250. The amount of light detected by this light detecting element 250 is fed back to the amount of light emitted by the light emitting unit 470.

[0225] A light-reflecting diffuser 460 may be used as the diffuser 460 arranged on the light-collecting surface, and this light-reflecting diffuser 460 may be tilted. By adjusting the amount of tilt, the light reflected by the light-reflecting diffuser 460 may be directed toward the front of the paper. In this case, a collimating lens or imaging lens 450 is placed in the middle of the light path that travels toward the front of the paper. Such an optical arrangement has the effect of enabling the light source unit 2 to be significantly thinner.

[0226] 27A, piezoelectric elements 526 and 528 may be attached to a light-reflecting diffuser plate 460 that is disposed at an angle, and the angle of inclination of the light-reflecting diffuser plate 460 may be changed over time. Alternatively, a light-reflecting plate 520 connected to piezoelectric elements 526 and 528 may be installed in the same location as the light-reflecting diffuser plate 460 instead of the light-reflecting diffuser plate 460. The data (or images) collected by the measurement unit 8 for each different angle of inclination may then be added or averaged over time to further reduce speckle noise (more details on speckle noise reduction will be described later in Section 8.2).

[0227] 9G, the Fθ lens or collimator lens 324 may be omitted from the embodiment shown in Fig. 9I. In this case, the reflected light is focused by providing a macroscopic concave curved surface on the entire incident surfaces 92-1 to 92-3 of the reflective predetermined optical member 90.

[0228] Chapter 4 Hybrid Light Source and Its Usage Section 4.1 Relationship between biological components and absorption wavelengths There is no universal light source for the existing light sources that make up the light-emitting unit 470; each has its own advantages and disadvantages. For example, a single existing LED (light-emitting diode) element has a relatively narrow emission wavelength range, making it unsuitable as a stand-alone light source for measuring spectral characteristics. On the other hand, thermal emission sources such as halogen lamps have a wide emission wavelength range, but suffer from the problem of relatively low emission intensity.

[0229] In this embodiment, a hybrid light source unit that combines multiple light-emitting elements is used. This broadens the range of uses for the light source unit 2, and creates the effect of being able to provide a variety of services to users. When providing a variety of services to users, safety is extremely important. Semiconductor laser light and LED light can produce high light intensity, but high emission intensity in the visible light range poses a risk of damaging the human eye.

[0230] Figure 10A shows the relationship between the absorption wavelengths of each biological component 988 for near-infrared light in the 0.9 μm to 1.8 μm wavelength range. The 1.35 μm to 1.80 μm wavelength range is called the first overtone region and has a relatively large amount of light absorption. Within this wavelength range, proteins, carbohydrates, and lipids have relatively large amounts of light absorption, in that order, from short wavelength to short wavelength. The 0.90 μm to 1.25 μm wavelength range is called the second overtone region and has a relatively small amount of light absorption. Within this wavelength range, the absorption wavelengths of each biological component 988 are ordered from short wavelength to short wavelength: carbohydrates, proteins, and lipids. Here, the characteristic of water, which has a very large amount of absorption, is important in the wavelength range above 1.35 μm, which corresponds to the first overtone and combination overtone regions. On the other hand, water has a small amount of absorption in the wavelength range below 1.35 μm, which corresponds to the second overtone region.

[0231] Figure 10B shows the cross-sectional structure of the human eye. Light entering from the outside world passes through the lens 158 and vitreous body 154 and reaches the retina 150. This retinal portion 150 is most susceptible to damage from light irradiation. The lens 158 and vitreous body 154 contain a large amount of water. Therefore, light in the wavelength range of 1.35 μm or more, which is highly absorbed by water, is absorbed by the lens 158 and vitreous body 154 and does not reach the retina 150.

[0232] For the above reasons, when using semiconductor laser light with high emission intensity, setting the wavelength of the semiconductor laser light to 1.35 μm or longer can significantly reduce the risk of eye damage. On the other hand, near-infrared light with a wavelength exceeding 1.8 μm (especially 2.4 μm) is too affected by moisture. Therefore, when using near-infrared light with a wavelength exceeding 1.8 μm (especially 2.4 μm), there is a risk that the light will be absorbed by water droplets or wetness on the surface of the measurement object 22, significantly reducing measurement accuracy.

[0233] Therefore, in this embodiment, when the measurement unit 8 uses reflected light from the measurement object 22, including a human, and further when a laser light emitting element (such as the semiconductor laser element 500) is disposed in the hybrid light source unit, the value of the central emission wavelength λ0 of the laser light emitting element (such as the semiconductor laser element 500) is set to 1.35 μm or more and 2.4 μm or less (preferably 1.8 μm). This has the effect of ensuring high measurement accuracy while reducing the risk of eye damage.

[0234] The optical characteristics shown in Figure 10A provide important information for measuring the inside of a living organism. An example will be described below, in which the spectral characteristics of light transmitted through a living organism with a thickness of approximately 1 cm, such as a fingertip, were investigated. Light with a wavelength of 1.35 μm or less (intra-living organism scattered light) passes through a living organism with a thickness of approximately 1 cm, and the characteristics of the transmitted light can be detected as a signal. In contrast, light with a wavelength exceeding 1.35 μm is absorbed by the water in the living organism, and almost no signal can be detected as transmitted light. This situation is nearly consistent with the wavelength dependence of light absorption by water shown in Figure 10A. Therefore, in this embodiment, which measures the characteristics inside a living organism, the wavelength of light emitted from the hybrid light source unit is set to 1.35 μm or less.

[0235] Furthermore, measurements using light in the second harmonic region, as shown in Figure 10A, enable measurements with relatively high accuracy. As can be seen from Figure 10A, the measurement wavelength suitable for the second harmonic region is 0.9 μm or longer. Therefore, in this embodiment, when measuring characteristics inside a living body, the wavelength of the light emitted from the hybrid light source is set to 0.9 μm or longer and 1.35 μm or shorter.

[0236] Next, we will explain the role of laser light in this embodiment when measuring characteristics inside a living body using a hybrid light source unit with a laser light emitting element (such as a semiconductor laser element 500) installed inside. Laser light has high emission intensity but a narrow emission wavelength range, so it is not suitable for measuring spectroscopic characteristics by itself. Therefore, in this embodiment, laser light of a specific wavelength can be used to measure objects inside a living body that change over time, such as pulsation or respiration.

[0237] Furthermore, when simultaneously measuring the spectral characteristics inside a living body using light emitted from another light source installed inside the hybrid light source, it is necessary to devise a way to ensure that the laser light wavelength does not interfere with this spectral characteristic measurement. As mentioned above, when measuring the spectral characteristics inside a living body using light emitted from this other light source, measurement in the second overtone region is suitable. As shown in FIG. 10A, the longest wavelength absorbed by lipids in the second overtone region is around 1.25 μm. Therefore, in this embodiment, the laser light wavelength that does not interfere with this spectral characteristic measurement may be set to 1.25 μm or more. The above considerations can be summarized as follows. That is, when measuring the characteristics inside a living body using the hybrid light source in this embodiment, the emission wavelength range of the laser light emitting element (such as the semiconductor laser element 500) installed inside the hybrid light source may be set to 1.25 μm or more and 1.35 μm or less.

[0238] Section 4.2 Example of hybrid light-emitting section internal structure 11A shows an example of the internal structure of the hybrid light-emitting unit 470 in this embodiment. As explained in the previous section, measuring the spectroscopic characteristics inside a living body requires a measurement wavelength range of 0.9 μm to 1.25 μm that utilizes the second overtone region. Therefore, it is desirable to emit light in a wide wavelength range of 0.9 μm to 1.3 μm, which includes a margin in addition to this measurement wavelength range. However, it is difficult to achieve light emission in such a wide wavelength range with a single existing LED light source.

[0239] In order to achieve light emission in the above-described wide wavelength range, this embodiment uses phosphors 162 and 164 that emit near-infrared light. Phosphor 162 that emits near-infrared light with a central fluorescent wavelength on the short wavelength side and phosphor 164 that emits near-infrared light with a central fluorescent wavelength on the long wavelength side are stacked. The sum of the light emission characteristics of the individual near-infrared light-emitting phosphors 162 and 164 produces fluorescent near-infrared light 178 in the wavelength range of 0.9 μm to 1.3 μm.

[0240] This laminated structure is then fixed within a transparent sealing area 166 made of transparent resin. Furthermore, the outside of this transparent sealing area 166 is surrounded by a waterproof coating layer 168 containing a material with low moisture permeability, such as polyethylene, transparent silicone, or transparent Teflon (registered trademark). The waterproof coating layer 168 acts to prevent moisture from the outside from penetrating into these phosphors 162, 164.

[0241] Two light-emitting sources 160, 170 are arranged within this hybrid light-emitting unit 470, and a common electrode 174 is shared for power sharing. Light emitted from an LED light source serving as the first light-emitting source 160 excites near-infrared light-emitting phosphors 162, 164. Therefore, the emission wavelength of this excitation LED light source must be shorter than the fluorescent wavelength emitted in the range of 0.9 μm to 1.3 μm. An LED light source with an appropriate emission wavelength in the range of 600 nm to 900 nm is selected to match the characteristics of the near-infrared light-emitting phosphors 162, 164.

[0242] A semiconductor laser light source (semiconductor laser element 500) may be used as the second light source 170. The second light source 170 may have an emission wavelength longer than the fluorescence wavelength (emission wavelength) of the near-infrared light emitting phosphors 162, 164. As a result, the emitted light 176 from the second light source 170 passes through the near-infrared light emitting phosphors 162, 164 without affecting them in any way, and can be effectively used outside the hybrid light-emitting unit 470.

[0243] Although not shown in Fig. 11A, two photodetectors may be disposed in the hybrid light-emitting unit 470 to monitor the individual amounts of light emitted from the first and second light-emitting sources 160 and 170. By using these photodetectors to provide feedback to the individual amounts of light emitted, the amounts of light emitted from the first and second light-emitting sources 160 and 170 can be stabilized.

[0244] Section 4.3 Materials and structure of near-infrared emitting phosphors and their production methods We begin by explaining the phosphor material that emits near-infrared light. In this embodiment, the phosphor material contains atoms or ions belonging to rare earth elements or transition elements. By using this phosphor material, fluorescent properties that emit near-infrared light are obtained. As a specific embodiment example, an inorganic crystal (oxide crystal) containing tetravalent chromium ions or trivalent chromium ions, which belong to the transition elements, was used as the material, and as a result, the maximum emission wavelength appeared in the wavelength range of 1030 nm to 1350 nm.

[0245] An embodiment in which atoms or ions belonging to rare earth elements are contained in the phosphor material will be described. Trivalent ytterbium ions (Yb) are used as the rare earth elements. 3+ When using trivalent neodymium (Nd), the maximum emission wavelength appeared in the wavelength band around 1 μm. 3+ When using samarium trivalent Sm, maximum emission wavelengths appeared in the wavelength bands of 0.9 μm, 1.06 μm, and 1.3 μm. 3+ When used, fluorescence emission was observed in a wide wavelength range from 0.85 μm to 1.2 μm. Also, as an atom or ion belonging to the rare earth elements, trivalent erbium (Er) 3+ and trivalent praseodymium Pr 3+ Furthermore, in this embodiment, the phosphor material is not limited to this and may be made of any atoms or ions belonging to rare earth elements or transition elements.

[0246] 11B shows the detailed structure of near-infrared light-emitting phosphors 162 and 164 in this embodiment. Phosphor materials 182 to 186 with different particle sizes (having a predetermined particle size distribution) are dispersed within binder region 180. Binder region 180 may be made of glass material such as SiO2, bismuth oxide Bi2O3, or antimony oxide Sb2O3. However, the binder region 180 may also be made of other materials such as epoxy resin, acrylic resin, or silicone resin.

[0247] Phosphor 182 contains A, either an atom or ion belonging to a rare earth element or a transition element, as described above. Phosphor 184 contains B, either an atom or ion belonging to a rare earth element or a transition element different from A. Phosphor 186 contains C, either an atom or ion belonging to a rare earth element or a transition element different from A and B. As described above, the central emission wavelengths of the different atoms or ions A, B, and C when emitting fluorescence differ. Therefore, when phosphors 182 to 186 each containing different atoms or ions A, B, and C are mixed, the near-infrared light-emitting phosphors 162 and 164 can emit fluorescence over a wide wavelength range.

[0248] The central wavelengths of the fluorescent emissions of each type of ion described above correspond to the fluorescent emissions occurring within a relatively large mass. However, when the same ion is present near a surface, the electron orbital energy levels change slightly, resulting in a shift in the central emission wavelength. Furthermore, when the fluorescent materials 182-186 are made into fine particles with a particle size of approximately 3 μm-10 μm, interactions occur between the lattice vibrations (interatomic vibrations) within the fine particles and the electron orbital levels. Therefore, a change in the particle size of the fluorescent materials 182-186 changes the central wavelength of the fluorescent emissions. In this embodiment, this situation is utilized to provide a wide particle size distribution for the fluorescent materials 182-186 contained in the near-infrared-emitting phosphors 162 and 164. In this way, mixing fluorescent materials 182-186 with significantly different particle sizes significantly broadens the fluorescent wavelength range.

[0249] For ease of manufacturing, in this embodiment, the average particle size of the phosphors 182 to 186 is set to be within a range of approximately 0.5 μm to 100 μm. The particle size distribution range of the phosphors 182 to 186 in this embodiment is defined by the ratio range of the maximum particle size to the minimum particle size of the phosphors 182 to 186 contained in the same near-infrared light-emitting phosphors 162 and 164.

[0250] The minimum particle size in the fluorescent material 182 containing atoms (or ions) A belonging to rare earth elements or transition elements is D. A min, maximum particle size D A max, and the ratio between them is N A ≧D A max / D A min≧M A Similarly, the minimum particle size of the fluorescent material 182 containing atoms (or ions) B belonging to rare earth elements or transition elements is D B min, maximum particle size D B max, and the ratio between them is N B ≧D B max / D B min≧M B The manufacturing process is controlled so that the minimum particle size of the fluorescent material 182 containing atoms (or ions) C belonging to rare earth elements or transition elements is within the range of D. C min, maximum particle size D C max, and the ratio between them is N C ≧D C max / D C min≧M C Production is managed to stay within this range.

[0251] After checking various things, M A and M B , M C It was found that the appropriate value for N is 1.5, and preferably 4. A and N B , N C It was found that the appropriate values ​​for both are 1000 or 100, preferably 10.

[0252] 11C shows a method for producing a near-infrared light-emitting phosphor according to this embodiment. At the beginning of the production of the near-infrared light-emitting phosphor (ST01), lumps of phosphor containing atoms (or ions) A, B, and C belonging to the rare earth element or transition element shown in step 02 are prepared.

[0253] For example, to create a lump of fluorescent material containing the rare earth elements ytterbium, neodymium, or samarium, powders of their oxides, Yb2O3, Nd2O3, and Sm2O3, are prepared. Powders of glass SiO2, bismuth oxide Bi2O3, and antimony oxide Sb2O3 are also prepared as inorganic materials (oxide materials) to be mixed with these. These are then mixed individually and kept at a temperature of 1250°C for about 10 minutes, at which point they melt and form a lump of fluorescent material.

[0254] In step 03, the lump is crushed into powder. It is crushed until the average particle size of each phosphor particle in the powder is approximately 3 μm to 10 μm. As mentioned above, the fluorescent emission intensity distribution characteristics in the wavelength direction of the near-infrared light-emitting phosphors 162 and 164 are greatly affected by the particle size distribution of the phosphor. Therefore, the powder obtained by crushing is sorted by particle size using a sieve with uniform mesh size. First, the crushed powder is passed through a sieve with large mesh size to remove phosphors with particle sizes that do not meet the standard. Next, the mesh size of the sieve is gradually reduced to sequentially select phosphors with particle sizes within a specified range. In this way, phosphor powders 182 to 186 with the specified particle size distribution are extracted (ST04).

[0255] In step 05, phosphor powders 182-186 having the respective particle size distributions are mixed with a liquid or powder binder 180. Next, this liquid or powder binder 180 is solidified (cured or solidified) (ST06), completing the production of the near-infrared light-emitting phosphor (ST07). If a glass material is used as the binder 180, the powdered glass material and the phosphor powders 182-186 are mixed and then heated to a high temperature to harden. If an organic material such as epoxy resin or silicone resin is used as the binder 180, it is left for a specific period of time until it hardens due to the action of the hardener. If an acrylic photocurable resin is used as the binder 180, it may be hardened by ultraviolet light irradiation.

[0256] Section 4.4: An embodiment in which the light source unit and the measurement unit are integrated into a compact unit 12A and 12B show a structure in which the hybrid light-emitting unit 470 described in Section 4.3 using Fig. 11A, the optical arrangement in the light source unit 2 described in Section 3.3 using Fig. 9F(a) and Fig. 9G, and the measurement unit 8 that performs spectroscopic measurement are integrated into a compact unit. In both of the embodiments shown in Fig. 12A and Fig. 12B, the hybrid light-emitting unit 470 described in Section 4.3 is used as the light-emitting unit 470.

[0257] 12A and 12B use a spectroscopic element 320 that uses a reflective blazed grating for spectral characteristic measurement. Light for each measurement wavelength that has been separated by this spectroscopic element 320 is focused on a line sensor 300 that is made up of a one-dimensionally arranged array of photodetector cells.

[0258] 12A differs from FIG. 9F(a) in that the light after passing through the predetermined optical member 90 is focused on the surface of the measurement object 22. That is, a turning mirror plate 314 is installed just before the focusing position of the light after passing through the predetermined optical member 90, where the light is turned back toward the back side of the paper. The light is then focused on the surface of the measurement object 22 installed on the back side of the paper (not shown).

[0259] As explained in Section 4.1, the light emitted from this hybrid light-emitting unit 470 enters the living body and is repeatedly diffusely reflected within the body. A portion of the light diffusely reflected within the body exits the surface (biological surface) of the measurement object 22. A portion of the light that exits the surface (biological surface) of the measurement object 22 passes through pinhole 310. The light that passes through pinhole 310 is reflected by half mirror plate 312 and becomes parallel light after passing through collimator lens or Fθ lens 322.

[0260] Since the light separating element 320 is slightly tilted, the light reflected by the light separating element 320 passes through the upper part of the half mirror plate 312 and reaches the line sensor 300 .

[0261] In this way, by bending the optical path midway using the return mirror plate 314 and the half mirror plate 312, it is possible to make the integrated structure of the light source unit 2 and the measurement unit 8 thinner.

[0262] Instead of using the structure of the example embodiment shown in FIG. 12A, the optical arrangement of FIG. 9F(b) may be used, in which the collimating lens or cylindrical lens 120 is removed.

[0263] A portion of Figure 12B utilizes the same optical arrangement as Figure 9G, and similarly to Figure 12A, the optical path is bent by two folding mirror plates 314 and 316, making it possible to reduce the thickness. The Fθ lens or collimator lens 324 used in Figure 12B may be eliminated, and instead the light reflecting surface of the reflective predetermined optical member 90 may be made a concave curved surface. This reduces the number of optical components, resulting in the effect of achieving a smaller and less expensive optical system.

[0264] Chapter 5: Other Examples of Optical Noise Reduction Section 5.1 Characteristics of speckle noise patterns Figure 13(a) shows the basic principle of speckle noise, a type of optical noise. Two light reflection areas 1046 are arranged at a distance P apart. Incident light 1042 is perpendicularly incident on the light reflection area 1046, and Figure 13(a) shows the reflection intensity of reflected light 1048 reflected in the θ0 direction. According to the theory of optical interference, the reflection intensity at this time is cos 2 It is proportional to (πPθ0 / λ). What is important here is that the reflection intensity changes periodically in the reflection direction θ0 of the reflected light 1048. This periodic change in reflection intensity is related to speckle noise.

[0265] Extending FIG. 13 further, consider a case where multiple light reflection regions 1046 are regularly arranged at a period P. When the position of the user's eye observing the reflected light 1048 is fixed, the reflection direction θ0 entering the user's eye changes for each reflection location within the multiple light reflection regions 1046. As a result, there are areas where the reflection amplitudes from adjacent light reflection regions 1046 reinforce each other and appear bright, and areas where the reflection amplitudes cancel each other out and appear dark. This appearance is called a speckle noise pattern.

[0266] FIG. 13(b) shows the case where the incident angle of the incident light 1042 to the two light reflecting regions 1046 is θ i According to the theory of light interference, the reflection intensity at that time is cos 2 {πP(θ0-θ i ) / λ}.

[0267] As explained in Section 2.3 with reference to FIG. 7C, since there is no optical interference between different wave trains, light synthesis between different wave trains corresponds to intensity addition (synthesis of light intensity values). For example, as shown in FIG. 13(a), a first light 202 containing a part of at least one wave train is made to be perpendicularly incident on two light reflecting regions 1046. At the same time, a second light 204 containing at least a part of another wave train that does not optically interfere with the above wave train is made to be incident at an incident angle θ as shown in FIG. 13(b). i Then, the light intensity of the combined light (intensity-added light) reflected in the θ0 direction is cos 2 (πPθ0 / λ)+cos 2 {πP(θ0-θ i ) / λ}. For example, when the light intensity of the first term in the previous equation is at its maximum, the light intensity of the second term is minimized by θ i Optimizing the value of will cancel out (average or smooth) the maximum and minimum light intensity, resulting in a significant reduction in speckle noise (optical noise).

[0268] In other words, consider a situation where the first light 202 and the second light 204 do not interfere with each other (or the amount of interference is small) due to a phase asynchronous (phase discontinuous) relationship 402. If the first light 202 and the second light 204 are simultaneously irradiated onto the measurement object 22 with different irradiation angles, speckle noise (optical noise) is reduced.

[0269] 13, for simplicity of explanation, the explanation is given with the addition of the intensities of only two mutually incoherent (or low coherent) light beams 202 and 204. However, the invention is not limited to this, and three or more (or four or more) types of mutually incoherent light beams 202, 204, and 206 may be simultaneously irradiated onto the measurement object 22 by changing the irradiation angles. Increasing the number of irradiations of mutually incoherent (or low coherent) light beams increases the number of speckle noise (optical noise) averaged, and therefore the speckle noise (optical noise) reduction effect is improved.

[0270] FIG. 14A shows an example embodiment of an optical arrangement that utilizes the above principle to reduce speck noise (optical noise). A phase characteristic conversion element 1050, such as a diffuser, is used to irradiate the light beams 202, 204, and 206 that have passed through different regions 212, 214, and 216 onto the light-irradiated object 1030 while varying their irradiation angles. The surface of the phase characteristic conversion element 1050 has a finely textured shape, which diffuses the light that passes through it. The irradiation angle at a given position on the light-irradiated object 1050 changes between θ1, θ2, and θ3 for the first light beam 202, the second light beam 204, and the third light beam 206. At the same time, the first light beam 202, the second light beam 204, and the third light beam 206 are irradiated onto the same position while overlapping each other.

[0271] Because the irradiation angles are different, the speckle noise (optical noise) patterns that appear on the light irradiation object 1050 differ between the first light 202, the second light 204, and the third light 206. Because the first light 202, the second light 204, and the third light 206 are in a non-interfering (or low-interfering) relationship, the different speckle noise patterns mix together on the light irradiation object 1030. As a result, the speckle noise patterns are averaged (smoothed), and the overall amount of speckle noise (optical noise) decreases.

[0272] Here, consider the correspondence between FIG. 14A and FIG. 9A. As described above, the first light 202, the second light 204, and the third light 206 overlap and are irradiated on the surface of the light-irradiated object 1050. Therefore, the surface of this light-irradiated object 1050 corresponds to the light synthesis location 220. Furthermore, consider that the surface of this light-irradiated object 1050 also serves as the incident surface 92 of a predetermined optical component. In this case, the perpendicular line perpendicular to the surface of this light-irradiated object 1050 corresponds to the incident surface perpendicular line 96. As shown in FIG. 14A, the angles θ1, θ2, and θ3 are formed between the directions of travel of the first light 202, the second light 204, and the third light 206 traveling toward the light-irradiated object 1050 and the incident surface perpendicular line 96, respectively. As is clear from FIG. 14A, the relationship θ1 ≠ 0 holds true for the angle θ1 formed between the direction of travel of the first light 202 and the incident surface perpendicular line 96.

[0273] Fig. 14B shows an application example of this embodiment. In Fig. 14B, incoherent (or low-coherent) light beams 202, 204, and 206 are focused at spatially different positions. When a Kohler illumination system 1026 is used as the illumination system for the light irradiation object 1030, the light beams 202, 204, and 206 focused at different positions are mixed (overlapped) with each other and irradiated at any position within the light irradiation object 1030. In addition, the irradiation angles at this time are different from each other. As a result, the speckle noise pattern is averaged (smoothed), and the overall speckle noise (optical noise) is reduced.

[0274] 14B uses a fly-eye lens 1028, which is a lens having a plurality of optical axes arranged in the same space, as a method for focusing the non-interfering (or low-interfering) light beams 202, 204, and 206 at different spatial positions. In FIG. 14B(a), this fly-eye lens 1028 is arranged immediately behind the optical property conversion element 210. In FIG. 14B(b), this fly-eye lens 1028 is arranged immediately before the optical property conversion element 210 and is formed integrally with the optical property conversion element 210.

[0275] 14B(a) and 14B(b), the third, second, and first light beams 206, 204, and 202 that have passed through the third, second, and first regions 216, 214, and 212, respectively, are focused at positions α, β, and γ, respectively. By using the Kohler illumination system 1026, the light beams 206, 204, and 202 that have passed through the respective focusing positions are mixed together and illuminate the light illumination object 1030 at different illumination angles.

[0276] 14B uses a fly-eye lens 1028 as a method for focusing light 206, 204, 202 passing through different regions 216, 214, 212 at different positions α, β, γ. However, this is not limiting, and any other method may be used to focus light at different positions α, β, γ. In another embodiment, a liquid crystal lens array may be used instead of the fly-eye lens 1028.

[0277] As an application example of this embodiment, instead of using a single-core fiber, a fiber bundle 1040 may be used. FIG. 14C(a) shows an application example using a fiber bundle 1040. The light source unit 2 is composed of a light emitting unit 470 and an optical property conversion unit 480. The first light 202 and the second light 204, which are incoherent (or have low coherence) and emitted from the light source unit 2, are irradiated onto the measurement object 22 by a Kohler illumination system 1026. The focal length of the collimating lens 318 installed in the Kohler illumination system 1026 controls the value of the difference in illumination angle between the first light 202 and the second light 204 irradiated onto the measurement object 22. In other words, if the focal length of the collimating lens 318 is short, the difference in illumination angle between the first light 202 and the second light 204 becomes large.

[0278] In the optical property conversion element 210 disposed in the optical property conversion unit 480, the thickness differs between the first region 212 and the second region 214. When the difference in optical path length between the first region 212 and the second region 214 exceeds the coherence length ΔL0 (or twice the coherence length ΔL0), the coherence between the first light 202 and the second light 204 decreases.

[0279] The condenser lens 314 condenses the first and second light beams 202, 204 onto the incident surface of the bundle fiber 1040. Here, the first light beam 202 and the second light beam 204 each enter different core regions within the bundle fiber 1040. The difference in the core regions through which the light beams pass, in combination with the collimator lens 318, changes the traveling direction between the light beams 202, 204 emitted from the bundle fiber 1040.

[0280] 14C(b) shows an optical system in which a phase characteristic conversion element 1050 is arranged just before the incident surface of the bundle fiber 1040, as compared to FIG. 14C(a). The first and second light beams 202 and 204 that have passed through this phase characteristic conversion element 1050 have their phase characteristics converted and enter the bundle fiber 1040. Specifically, the phase characteristic conversion element 1050 may be a diffusion plate with a fine structure on its surface, such as frosted glass. However, it is not limited to this, and a grating, a hologram element, a Fresnel zone plate, or the like may also be used.

[0281] 14C(c), compared to FIG. 14C(b), a phase characteristic conversion element 1050 is arranged near the focusing plane of the first light 202 and the second light 204. In FIGS. 14C(a) and 14C(b), the first light 202 and the second light 204 mainly pass through different core regions in the bundle fiber 1040 separately. In contrast, in FIG. 14C(c), the first light 202 and the second light 204 mix with each other when passing through the phase characteristic conversion element 1050. As a result, the first light 202 and the second light 204 pass through the same core region in the bundle fiber 1040.

[0282] Figure 14D shows the results of an actual experiment conducted to confirm the effectiveness. The horizontal axis of Figure 14D represents the position on the measurement object. The vertical axis of Figure 14D represents the measured light intensity. When the amount of speckle noise is large, the amount of fluctuation in the measured light intensity appears large. A diffuser plate with an Ra value of 2.8 μm, which represents the average height of surface irregularities, was used as the measurement object 22.

[0283] Fig. 14D(a) shows the measurement result of the speckle pattern when conventional light that passed through the core region of a single optical fiber or the center of the optical guide 330 / 332 / 340 was irradiated onto the measurement object 22. In Fig. 14D(a), the fluctuation of the light intensity is large, and large speckle noise appears.

[0284] Figure 14D(b) shows the measurement results of the speckle pattern when the optical system of Figure 14C(b) was used. The optical conversion element 210 was made of quartz glass and consisted of 48 divided elements, each with a thickness of 1 mm. A diffuser with an Ra value of 0.5 μm was used for the phase characteristic conversion element 1050. The bundle fiber 1040 was 1.5 m long, and 320 optical fibers, each with a core diameter of 230 μm and an NA of 0.22, were bundled within a 5 mm diameter area. The focal lengths of the condenser lens 314 and collimator lens 318 were both set to 50 mm. Compared to Figure 14D(a), Figure 14D(b) shows significantly reduced optical interference noise (speckle noise).

[0285] Section 5.2 Characteristics of various optical fibers and characteristics of light passing through the core region In this section 5.2, we will explain the characteristics of various optical fibers and the properties of light passing through the core region 112 of the optical fiber. Then, in the next section 5.3, we will explain a method for reducing speckle noise using these properties. First, we will explain the difference between single-mode fiber and multimode fiber, which are both single-core fibers.

[0286] 15A(a) shows the characteristics of a single-mode fiber. A cladding region 114 made of a material with a relatively low refractive index is arranged to surround the periphery of a core region 112 with a relatively high refractive index. Here, if the refractive index of the core region is represented by n1 and the refractive index of the cladding region is represented by n2, then there is a relationship of n1>n2.

[0287] The optical amplitude distribution of light propagating within the core region 112 of this single-mode optical fiber shows the characteristics shown on the right side of Figure 15A(a). That is, the optical amplitude is maximum near the center of the core region 112, and decreases as one approaches the periphery of the core region 112. This optical amplitude distribution (mode of the amplitude distribution) or electric field distribution 152 within the core region 112 is called the "fundamental mode."

[0288] The minimum wavelength λ of light propagating within the core region 112 when the characteristics shown on the right side of FIG. 15A(a) are always satisfied is C The value of is, when the diameter in the core region is D,

[0289]

number

[0290]

number

[0291] However, when the diameter D in the core region becomes larger than the condition of Equation 22, the amplitude distribution of light in the core region 112 (the mode of the amplitude distribution) takes an amplitude distribution different from the amplitude distribution on the right side of FIG. 15A. An optical fiber in which an amplitude distribution other than the fundamental mode (another mode) can be formed in the core region 112 is called a multimode fiber. Here, the mode (amplitude distribution) other than the above fundamental mode is called the "higher-order mode". Using the relationship of Equation 22 above, the condition for a multimode fiber is

[0292]

Number

[0293] FIG. 15A(b) shows a method of collecting light in the core region 112. The condenser lens 330 condenses light into the core region 112. Here, due to the wave nature of light, the condensed spot has a spread of width d. Between the half-value θ of the aperture angle of the condenser lens 330 and the wavelength λ of the light to be condensed, there is

[0294]

Number

[0295]

Number

[0296]

Number

[0297] Figure 15B shows the characteristics of two types of optical fiber. The right side of Figure 15B shows the refractive index profile 138 in the core region 112 and cladding region 114. Here, the vertical axis indicates the position 124 in the cross section of the optical fiber. The optical fiber shown in Figure 15B(a) is a step-index (SI) optical fiber in which the refractive index is uniform throughout the core region 112. The optical fiber shown in Figure 15B(b) is a graded-index (GI) optical fiber. In this GI optical fiber, the refractive index is high in the center of the core region 112 and low in the peripheral region. In this embodiment, either an SI type or a GI type optical fiber may be used.

[0298] In both SD and GI optical fibers, there is a limit θmax to the convergence angle of light that can pass through the core region 112. That is, light that exceeds θmax as the half-value θ of the convergence angle when light is focused by the focusing lens 330 in Figure 15A(b) cannot be totally reflected at the interface between the core region 112 and the cladding region 114. Therefore, as shown by the dashed arrow in Figure 15B, this light travels from the core region 112 through the cladding region 114 and exits the optical fiber.

[0299] The sine function value of θmax at this time, sin(θmax), is defined as the NA value of the optical fiber. The condition that this NA value satisfies is as follows:

[0300]

number

[0301]

number

[0302] Equation 28 shows the conditions under which a higher-order mode can occur in the core region 112. Therefore, the condition under which only the fundamental mode occurs in the core region 112 is given by reversing the direction of the inequality sign in Equation 28. In addition, the condition for the incident angle θ for light propagation in the core region 112 is

[0303]

number

[0304]

number

[0305] Section 5.3 Speckle noise pattern reduction method using mode characteristics in optical fiber FIG. 15C explains the relationship between the incident angle θ of light when it enters the core region 112 and the mode (electric field distribution 152) when the light propagates within the core region 112. First, the relationship between FIG. 15C and FIG. 9A will be explained. The inside of the core region 112 of the optical fiber corresponds to the predetermined optical member 90. The inside of the core region 112 also serves as the light combining location 220. The entrance surface of the optical fiber (inner core region 112) corresponds to the incident surface 92 of the predetermined optical member. Furthermore, when the incident surface of the optical fiber has a structure in which it is cut vertically, the optical axis direction of the optical fiber (inner core region 112) becomes parallel to the incident surface side normal 96. Then, between incident lights having different incident angles θ into the core region 112, a first light 202 and a second light 204 can be distinguished.

[0306] 15C(a) shows a state in which second light 204 is incident into core region 112. Second light 204 is incident into core region 112 from a direction approximately parallel to incident surface normal 96. Also consider the case in which second light 204 is incident at approximately the center of core region 112. The incident angle θ (the angle between the incident direction of second light 204 and incident surface normal 96) at this time satisfies the condition of Equation 30. Therefore, electric field distribution 152 of second light 204 in core region 112 forms the fundamental mode (TE (transverse electric) 1).

[0307] 15C(b) shows a state in which the first light 202 is incident on the core region 112. As explained in FIG. 9A, the first light 202 and the second light 204 travel in different directions immediately before the incident surface 92 of the predetermined optical member (here, optical fiber) 90. Therefore, the relationship θ≠0 holds for the incident angle θ of the first light 202 (the angle between the incident direction of the first light 202 and the incident surface normal 96). However, consider the case in which the first light 202 passes through the center of the core region 112 on the incident surface 92 of the predetermined optical member (the incident surface of the core region 112).

[0308] In FIG. 15C, when a multimode fiber is used (however, either an SI type or a GI type may be used), the diameter D of the core region 112 satisfies Equation 28 (or Equation 23). In order to ensure high light utilization efficiency at this time, the incident angle θ of the first light 202 is set so as to satisfy Equation 26 (or Equation 25). Here, this incident angle θ must satisfy the condition of Equation 29. Therefore, with regard to the range of the incident angle θ of the first light 202,

[0309]

number

[0310] 15C(b), the electric field value of the TE2 mode within this higher-order mode is 0 at the center of the cross-sectional position 132 within the core region 112. The polarity of the electric field is reversed in the direction in which the cross-sectional position 132 within the core region 112 shifts.

[0311] The difference between the fundamental mode (TE1 mode) and the TE2 mode within the core region 112 is manifested in the difference in the intensity distribution characteristics of the light emitted from the optical fiber. For example, when second light 204 propagates within the core region 112 in the fundamental mode (TE1 mode), the light cross-sectional intensity distribution (Far Field pattern) at a location away from the point of emission from the optical fiber is an intensity distribution in which the center is bright and the periphery is dark. On the other hand, when first light 202 propagates within the core region 112 in the TE2 mode, it exhibits a doughnut-shaped intensity distribution in which the center is relatively dark and areas slightly shifted from the center are bright. Therefore, by observing the intensity distribution of the light emitted from the optical fiber, the difference in the mode of the light propagating within the core region 112 can be predicted.

[0312] The value of κ in Equation 31 is determined from the experimental results of Figure 17A. It is thought that the value of κ is appropriate to be 3 / 4 (preferably 1 / 2). Furthermore, when κ is set to 1 / 4, the probability of obtaining the TE2 mode increases.

[0313] FIG. 15C(c) shows a state in which the incident angle θ of the third light 206 (the angle between the traveling direction of the third light 206 immediately before it is incident on the incident surface 92 of the predetermined optical member and the incident surface side normal 96) is set to be even larger than that of the first light 202. The condition of the incident angle θ in this case is as follows:

[0314]

number

[0315] When light focused using the focusing lens 330 enters the core region 112, the incident angle θ changes at the position where the light passes through the focusing lens. As a result, light propagates through the core region 112 in a state where different mode-forming lights are mixed.

[0316] Figure 16A shows a combination of symmetrical and asymmetrical mode-forming light beams with respect to the center position within the core region 112. Figure 16A(a) shows the electric field distribution 152 of the symmetrical fundamental mode (TE1 mode)-forming light beam. Figure 16A(b) shows the electric field distribution 152 of the asymmetrical TE2 mode-forming light beam. Figure 16A(c) shows the combined electric field distribution 152 of both.

[0317] In the TE2 mode shown in FIG. 16A(b), the position 124 showing a large electric field value can be on either the left (L) or the right (R). Therefore, when the intensity distribution of the combined light (FIG. 16A(c)) is calculated, the center of gravity position is shifted between the left (L) and right (R) diagrams. That is, on the left (L) diagram of FIG. 16A(c), the center of gravity position 116A is shifted to the left of the center position in the core region 112. On the right (R) diagram of FIG. 16A(c), the center of gravity position 116B is shifted to the right of the center position in the core region 112. This center of gravity position shift is not limited to light forming the TE2 mode. For example, when combining any light, such as TE4 or TE6, whose electric field distribution 152 exhibits asymmetric characteristics, a center of gravity position shift occurs. The explanation up to this point has mainly focused on SI-type optical fibers. However, the above explanation is not limited to SI-type optical fibers, and is similarly applicable to GI-type optical fibers.

[0318] 16B shows an embodiment in which speckle noise is reduced by utilizing this center of gravity shift. A mask pattern MP is placed in the optical path of the parallel light to extract only the upper sectorial region A within the laser beam cross section 510. A condenser lens 330 condenses the extracted light into the core region 112 of the waveguide element (optical fiber / optical waveguide / light guide) 110. At the exit of the waveguide element (optical fiber / optical waveguide / light guide) 110, a center of gravity position 116A of the intensity distribution is generated at a position shifted from the center position of the core region 112. A collimator lens 318 converts the light emitted from the waveguide element (optical fiber / optical waveguide / light guide) 110 into parallel light.

[0319] When only the lower sectorial region B in the laser beam cross section 510 is extracted, a center of gravity position 116B of the intensity distribution occurs in the exit plane of the waveguide element (optical fiber / optical waveguide / optical guide) 110. This center of gravity position 116B appears at a position opposite to the center of gravity position 116A with respect to the center position of the core region 112.

[0320] The traveling directions of the parallel light A and B after passing through the collimator lens 318 are slightly different from each other. Consider a case where a relationship (phase asynchrony 402) exists in which light A extracted from the upper sectorial region A and light B extracted from the lower sectorial region B do not interfere with each other. When the light A and B traveling in different directions are simultaneously irradiated onto the measurement object 22 using a Koehler illumination system, speckle noise is reduced as described in FIG.

[0321] 16C shows an embodiment example in which speckle noise is reduced using an optical property conversion element. The laser beam cross section 510 is divided into eight regions (angle division) in the angular direction around the optical axis. The light (elements) passing through each region have an optical path length difference of at least twice the coherence length ΔL0. As a result, eight center of gravity positions 116 of different intensity distributions are formed within the exit plane of the waveguide element (optical fiber / optical waveguide / light guide) 110.

[0322] When the laser beam cross section 510 is divided into an angle, an asymmetric electric field mode (such as TE2) is easily formed in the core region 112. This produces the effect of improving the speckle noise reduction effect.

[0323] 16C or 16B, condenser lens 330 condenses light onto incident surface 92 in core region 112. Experiments have confirmed that shifting the condensing position to increase the spot size incident on incident surface 92 in core region 112 reduces the speckle noise reduction effect. Increasing the spot size on incident surface 92 in core region 112 increases the frequency of total reflection at the interface between core region 112 and cladding region 114. A phase shift occurs due to total reflection at this interface, reducing the speckle noise reduction effect.

[0324] To ensure a large speckle noise reduction effect, the ratio of the spot size (diameter) to the inner diameter D of the core region 112 must be 1 or less. This ratio is preferably 3 / 4 or 1 / 2 or less.

[0325] Here, the spot size is defined as the effective beam diameter of the optical system. For example, this effective beam diameter may be defined as the diameter when the maximum diameter of the laser beam cross section 510 that can pass through the condenser lens 330 is projected onto the incident surface 92 in the core region 112. The light intensity on the condenser surface does not have a rectangular characteristic, but often has a light intensity distribution that is maximum at the center and decreases at the periphery. Taking this situation into consideration, the diameter of the range that takes half the maximum intensity in the intensity distribution on the incident surface 92 in the core region 112 (half width) or the e of the maximum intensity may be defined as the effective beam diameter. -2 The diameter of the range of values ​​(e -2 width) may be considered as the spot size.

[0326] Furthermore, if the center of the spot (laser light cross section 510) on the incident surface 92 in the core region 112 is significantly deviated from the center of the core region 112, the amount of phase shift caused by total reflection at the interface between the core region 112 and the cladding region 114 will increase. Therefore, the allowable amount of deviation between the center of the spot (laser light cross section 510) on the incident surface 92 in the core region 112 and the center of the core region 112 in order to obtain the speckle noise reduction effect will be explained. Where D is the inner diameter of the core region 112, this amount of deviation must be D / 2 or less. Furthermore, this amount of deviation is preferably D / 4 (or D / 8) or less.

[0327] The light in TE3 mode propagating within the core region 112 has symmetric electric field distribution characteristics with respect to the center position of the core region 112. Therefore, the light in TE3 mode does not contribute to increasing the amount of deviation in the center of gravity of the intensity distribution. Therefore, to effectively reduce speckle noise, it is desirable to satisfy the condition sinθ≦κNA for all incident angles θ of light incident on the core region 112.

[0328] Furthermore, the amount of deviation of the center of gravity in the intensity distribution of the combined light ( FIG. 16A(c) ) varies depending on the difference in the total amplitude between the second light 204 that forms the reference mode (TE1 mode) and the first light 202 that forms the TE2 mode. That is, increasing the relative total amplitude of the first light 202 that forms the TE2 mode increases the amount of deviation of the center of gravity in the intensity distribution of the combined light. Conversely, if there is no first light 202 that forms the TE2 mode, no deviation of the center of gravity in the intensity distribution of the combined light occurs. Therefore, to effectively reduce speckle noise, the maximum incident angle θ of all light entering the core region 112 must satisfy Equation 31.

[0329] In this embodiment, the difference in the incident angle (difference in the traveling direction) of the first light 202 and the second light is used to generate a difference in mode within the core region 112. Therefore, this embodiment is premised on the use of a multimode fiber (either SI type or GI type). Therefore, it is necessary to satisfy Equation 28 regarding the diameter D within the core region.

[0330] Section 5.4 Optical noise reduction effect Figure 17A shows the results of an experiment confirming the speckle noise reduction effect of this embodiment. 520 nm wavelength light emitted from semiconductor laser element 500 was passed through the optical system of Figure 16C. The light after passing through collimating lens 318 was reflected at a 90-degree angle by the surface of a diffuser plate with an average surface roughness Ra of 2.82 μm. The reflected light was then observed with a CCD camera. The multimode optical fiber used in the experiment was an SI type with a core diameter D = 600 μm, NA value = 0.22, and a total length of 1.5 m.

[0331] The standard deviation of the distribution characteristics obtained by dividing the fluctuation value of the measurement light intensity caused by speckle noise by the average value was defined as the speckle contrast Cs, and the Cs value when conventional light was used is shown on the left vertical axis of Fig. 17A. The ratio of the Cs value when optical property conversion element 210, which is angle-divided into eight regions, was used to the Cs value when conventional light was used is shown on the right vertical axis of Fig. 17A.

[0332] The horizontal axis of Fig. 17A represents the ratio of the NA value to the sine function value sinθ of the maximum incident angle θ for all light incident on the core region 112, calculated using the effective beam system. As the value on this horizontal axis increases, the effect of reducing spec noise increases.

[0333] Fig. 17B shows the change in Cs value when the angular division (horizontal axis) of the optical property conversion element 210 is changed. The experimental conditions are the same as those in Fig. 17A. When the angular division is 1, it shows the conventional optical system before using the optical property conversion element 210. When the number of angular divisions is increased, the amount of speckle noise decreases.

[0334] The effective NA value is defined as the sine function value of the maximum incident angle θ for all light entering the core region 112, calculated using the effective beam system. Figure 17B(a) shows the experimental results when the effective NA value was 1 / 29, and Figure 17B(b) shows the results when the effective NA value was 1 / 44. An optical fiber with an NA value of 0.22 was used in the experiment. Therefore, the converted value in Figure 17B(a) is NA / sinθ = 29 × 0.22 = 6.4, and the converted value in Figure 17B(b) is NA / sinθ = 44 × 0.22 = 9.7.

[0335] Chapter 6 Light source capable of emitting arbitrary waveforms in the time series direction Section 6.1 Optical system layout with high-speed control of light emission amount 18A shows an embodiment example of an optical system in the light source unit 2 that can support high-speed control of the light emission amount. A cross section 510 of light emitted from a semiconductor laser element 500 has an elliptical characteristic. To correct this elliptical characteristic, two cylindrical lenses 256, 258 are used whose bus bars are perpendicular to each other. That is, the cylindrical lens 256 corresponding to the major axis converts the light emitted from the semiconductor laser element 500 into parallel light in the major axis direction. Then, the cylindrical lens 256 corresponding to the minor axis converts the light emitted from the semiconductor laser element 500 into parallel light in the minor axis direction.

[0336] An optical property conversion element 210 that divides the angle into eight regions is placed where the laser beam cross section 510 becomes approximately circular. As shown in Fig. 17B, increasing the number of angular divisions in the optical property conversion element 210 increases the effect of reducing speckle noise. Therefore, this number of angular divisions may be set to any number.

[0337] The optical path changing prism 252 separates the light passing through the optical property changing element 210 into the light detecting element 250 and the wave guide element (optical fiber / optical waveguide / light guide) 110. The light input / output surface in the optical path changing prism 252 is an anti-reflection coated surface 246. Furthermore, at the total reflection surface 248, the light is totally reflected within the optical path changing prism 252.

[0338] The condenser lens 330-1 condenses a portion of the light reflected by the reflecting surface 254 onto the light receiving surface of the light detecting element 250. The condenser lens 330-2 condenses the remaining light toward the waveguide element (optical fiber / optical waveguide / optical guide) 110.

[0339] Section 6.2 Example of internal structure of light source Fig. 18B is a diagram illustrating some of the details of Fig. 1. Fig. 18B excerpts and illustrates only the photodetector element 250 and the semiconductor laser element 500 in the light source unit 2 shown in Fig. 18A.

[0340] The light emission amount control unit 30 is internally configured with a preamplifier circuit 716, a differential calculation circuit 712, and a current drive circuit 718. The light emission amount signal detected by the photodetector element 250 is amplified by the preamplifier circuit 716. The differential calculation circuit 712 calculates the difference between the light emission amount signal amplified by the preamplifier circuit 716 and a signal provided by the time-varying light emission amount generation circuit 728, and outputs this difference value to the current drive circuit 718. The current drive circuit 718 controls the light emission amount from the semiconductor laser element 500 by driving a current value according to this output signal to the semiconductor laser element 500.

[0341] The recording signal generation unit 32 is composed of a time-varying light emission amount generation circuit 728 and a memory circuit 726. This recording signal generation unit 32 can generate complex, arbitrary, time-varying light emission patterns. This enables light emission based on complex, arbitrary, time-varying light emission patterns. The memory circuit 726 stores these complex, arbitrary, time-varying light emission patterns. Information on these complex, arbitrary, time-varying light emission patterns may be recorded in advance in an external storage medium such as a USB memory or a hard disk. In this case, the time-varying light emission pattern information is transferred to the memory circuit 726 via the external storage element drive circuit 72 under the control of the control circuit 720.

[0342] For example, when performing complex time-series processing in cooperation between the light source unit 2 and the measurement unit 8, which will be described later in Chapter 8, highly accurate synchronization is required between the light source unit 2 and the measurement unit 8. A connection terminal for this synchronization is provided. A signal line 730 for synchronization with the outside (including the measurement unit 8) is connected to this synchronization connection terminal, and a reference clock synchronized with a signal transmitted through this signal line 730 for synchronization with the outside is generated in a reference clock generation circuit 732.

[0343] A communication control unit 740 is provided to perform time-series, highly accurate cooperative operation with the outside, including the measurement unit 8. This communication control unit 740 is included as part of the information transmission path 4 described in FIG. 1. The light source unit 2 described here is configured to be able to communicate information via either a wired or wireless communication medium. A wired communication execution unit 738 controls wired information communication with the outside. A wireless communication execution unit 736 controls wireless information communication with the outside. A communication control interface processing unit 742 processes information (data) regarding the content of information communicated via either a wired or wireless path.

[0344] Information communicated with the outside, including the measurement unit 8, may have a complex data structure, as will be described later in FIG. 19C. A communication information decryption unit 748 decrypts such complex data structures. The light emission pattern of the semiconductor laser element 500 may contain confidentiality information, and encrypted information may be transferred. An authentication processing control unit 746 performs processing related to the transfer of encrypted information, such as authentication processing with the communication partner and encryption key exchange.

[0345] The electronic circuit shown in FIG. 18B has been described as an example of application to the optical system described in FIG. 18A. However, the present invention is not limited to this, and may also be applied to, for example, the optical system shown in FIG. 9I. In this case, all operations can be performed simply by replacing the semiconductor laser element 500 in FIG. 18B with the light-emitting unit 470. In another embodiment, the electronic circuit shown in FIG. 18B may be applied to any light source unit 2. When the embodiments described in FIG. 18B are combined, the amount of light emitted can be controlled with high precision by allocating a portion of the light emitted from the light source unit 2 to the photodetector element 250 and monitoring the amount of light emitted.

[0346] Section 6.3 Example of light emission waveform setting format The complex and arbitrary time-varying light-emitting pattern generated within the recording signal generator 32 is basically set by a digital signal representing a "series of light-emitting amounts at predetermined time intervals." The light-emitting amounts at each elapsed time are expressed as binary data. Therefore, this time-varying light-emitting pattern may be represented in a CSV file format or a relational database format that represents a binary data series for each elapsed time.

[0347] FIG. 19A shows an example embodiment of a data format that defines a light emission waveform. Here, multiple different light emission patterns can be defined simultaneously. A time-varying light emission pattern ID (identification) 750 is set at the beginning so that each time-varying light emission pattern can be identified. Placing the time-varying light emission pattern ID (identification information) 750 at or near the beginning has the effect of making it easier to search for light emission patterns.

[0348] The method of the reference clock frequency 752 specifies the reference clock frequency generated by the reference clock generation circuit 732. The data step time interval 754 indicates the time interval when setting the light emission amount for each elapsed time. The time-varying light emission pattern duration 756 indicates the duration of the light emission pattern specified by the time-varying light emission pattern ID (identification information) 750. By using the information of the time-varying light emission pattern duration 756, the duration of the light emission pattern can be known in advance. As a result, the convenience of advance preparation for light emission control is improved.

[0349] The total number of steps 758 of the time-varying light emitting pattern represents the number of steps of the light emitting pattern that changes over time as defined by the time-varying light emitting pattern ID (identification information) 750. The value obtained by multiplying the total number of steps 758 of the time-varying light emitting pattern by the data step time interval 754 corresponds to the time-varying light emitting pattern duration 756.

[0350] The dynamic range (bit gradation number) 760 of the time-varying light intensity represents the number of bits representing the binary data that defines one light intensity. Increasing this number of bits allows for even minute changes in the light intensity to be set. The full-range output light intensity value 762 represents the light intensity value output from the light source unit 2 when the binary data is set to its maximum value.

[0351] The time-varying light-emitting pattern specified externally is basically identified using information in the time-varying light-emitting pattern ID (identification information) 750. In this embodiment, as an alternative method, the time-varying light-emitting pattern can be specified using an analog signal level input from outside. For example, a signal line for synchronization with the external device can be set to an analog level, and the time-varying light-emitting pattern can be switched using the signal level set on this signal line. The information used at this time corresponds to the maximum input signal level 764 that specifies the light-emitting pattern ID and the minimum input signal level 766 that specifies the light-emitting pattern ID. For example, the corresponding time-varying light-emitting pattern may be emitted during a period when the level of the analog signal input from outside is set to a level equal to or less than the maximum input signal level 764 that specifies the light-emitting pattern ID and equal to or greater than the minimum input signal level 766 that specifies the light-emitting pattern ID.

[0352] In this embodiment, when the light emission level is set to "0", the light source unit 2 basically emits no light. However, this is not limiting and the light may emit a small amount of light even when the light emission level is set to "0". This small amount of light can be set as the idling light emission amount value 770. When this idling light emission amount value 770 is other than "0", the value of the idling light emission amount flag 768 becomes "1". The binary data series indicating the amount of light emitted per elapsed time for each time-varying light-emitting pattern ID (identification information) 750 is arranged below the above data as binary values ​​elapse over time. The value of total data size 772 at this time is given by the product of the value set in total number of steps 758 of the time-varying light-emitting pattern and the value set in dynamic range (number of bit gradations) 760 of the time-varying light-emitting amount.

[0353] Section 6.4 Example of communication control of light emission 19B shows an example of communication control between the inside of the light source unit 2 and its outside. Here, the outside of the light source unit 2 that is the communication partner is called the host. In the embodiment of FIG. 1, this host may correspond to the in-system control unit 50.

[0354] Here, an example is shown in which the host 50 transmits a light emission pattern 788 to the light source unit 2 in advance, and then synchronizes the light emission timing between the host 50 and the light source unit 2. After this synchronization of the light emission timing, the light source unit 2 starts emitting light in the designated light emission pattern.

[0355] In either case of communication, a mutual authentication period 780 first occurs. First, the host 50 sends a host ID to the light source unit 2. When the light source unit 2 receives the host ID, it returns the light source unit ID to the host side. Next, the host 50 sends the host side encryption key to the light source unit 2, and then the light source unit 2 sends the light source unit side encryption key to the host 50 side. By setting up such a mutual authentication period 780, the effect is achieved that the light source unit 2 can communicate information with any device around the world via the Internet.

[0356] In the next control signal communication period 790, control signal information encrypted with a special key (for example, a composite key of the host-side encryption key and the light source-side encryption key) generated from the encryption key exchanged between the host 50 and the light source unit 2 is communicated.

[0357] In the light emission pattern transmission period 788, light emission pattern information is transmitted 784 after the control signal transmission period 790. Here, in the pattern transmission period 784 as well, light emission pattern information encrypted with a special key (for example, a composite key of a host-side encryption key and a light source-side encryption key) generated from the encryption key exchanged between the host 50 and the light source unit 2 is transmitted in the format of Fig. 19A.

[0358] On the other hand, during the light emission timing synchronization 798 period, the light emission period 794 begins after the control signal transmission period 790, and light emission in a designated pattern begins.

[0359] FIG. 19C shows an example of the data structure of the control signal 790 transmitted during the light emission timing synchronization period 798. The control signal 790 in FIG. 19C(a) has the data structure shown in FIG. 19C(b). The preamble 640 placed first is used for synchronization. The structure of the sender / receiver confirmation information 620 placed next (transmitted after the preamble 640) is shown in FIG. 19C(c). The host (sender) side ID (identification information) 622 is transmitted first, followed by the light source unit (receiver) side ID (identification information) 628. The information transmitted here may be an IP address instead of ID (identification information).

[0360] Type information of the control signal 790 currently transmitted is stored in the control signal identification information 642. Using this type information, it is possible to identify whether the period is a light emission pattern transmission period 788 or a light emission timing synchronization period 798.

[0361] Any of the identification information registered in the time-varying light-emitting pattern ID (identification information) in Fig. 19A can be written in the area of ​​light emission pattern identification information 750. The light source unit 2 decodes the information stored in this light emission pattern identification information 750 and recognizes the light emission pattern that will be emitted immediately after this.

[0362] The light emission start time designation information 648 designates the timing at which the light source unit 2 starts emitting light. Specifically, the start timing of the synchronization preamble 640 or the start timing of transmission (or start timing of reception) of this light emission start time designation information 648 is used as the reference timing, and the delay time from this reference timing to the start of light emission is specified. For example, when performing complex chronological processing in cooperation between the light source unit 2 and the measurement unit 8, which will be described later in Chapter 8, high-precision timing synchronization along the time axis (for example, at the 1 nS level) between the light source unit 2 and the measurement unit 8 is required. Using this light emission start time designation information 648 has the effect of enabling high-precision synchronization processing between the light source unit 2 and the measurement unit 8.

[0363] In the explanation given at the beginning of this document using Figure 1, a single optical element 10 incorporates the light source unit 2 described in Chapter 6. However, this is not a limitation; the light source unit 2 described in Chapter 6 may exist independently and be connected to a host 50 via the Internet. Using the light source unit 2 as part of any system on the Internet, rather than as a standalone type, has the effect of significantly broadening the application genre of the light source unit 2.

[0364] Chapter 7 Combining Optical and Electrical Noise Reduction Section 7.1 High-precision measurement methods in optical application fields Fig. 20A shows a high-precision measurement method according to this embodiment. Fig. 20A depicts an excerpt of the main parts of the optical device 10 described in Fig. 1. That is, optical measurement 1002 is performed on the measurement target 24 within the measurement unit 8. The signal processing unit 42 then analyzes the results of the optical measurement 1002 and extracts the necessary information 1004.

[0365] To perform highly accurate information extraction 1004, it is necessary to minimize disturbance noise in both the optical measurement 1002 and information extraction 1004 processes. Two types of disturbance noise, optical noise and electrical noise, are likely to be mixed in here. Therefore, to perform highly accurate measurements, it is desirable to reduce two types of disturbance noise: optical disturbance noise reduction and electrical disturbance noise reduction 1012.

[0366] By using the methods already explained in Chapters 2, 3, and 5, it is possible to significantly reduce optical noise. In the prior art, this optical noise reduction technology was not available, and therefore it was difficult to fully demonstrate the effects of electrical disturbance noise reduction processing. By combining 1012 the optical noise reduction methods already explained in Chapters 2, 3, and 5 with existing electrical disturbance noise reduction methods, it becomes possible to extract information 1004 with high accuracy.

[0367] As a specific method of combining the optical noise reduction method and the electrical disturbance noise reduction method 1012, the following procedure 1000 may be performed. This procedure 1000 is as follows: 1. Acquisition of first information using detected light from the measurement object 22 2. Using the first information, a process for reducing optical disturbance noise or electrical disturbance noise in the detection signal is performed 1012. 3. Acquisition of second information using the noise-reduced signal after the above processing The above processes are carried out sequentially.

[0368] The extracted information obtained here through the highly accurate information extraction 1004 is transferred 1006 via the information transfer path 4. An example of a transfer format 1014 used during this information transfer 1006 is: A) Reusing existing image or video compression methods or their extended formats B) Multiplexing and transferring packs or packets distributed by data type C) Individual transfer of each file linked (managed) within the hypertext You can also use the following.

[0369] The various pieces of information transferred 1006 in this transfer format 1014 are stored 1010 in the collected information storage area 74. Alternatively, they may be displayed 1008 on the display unit 18 or the information providing unit 72.

[0370] 20B shows a list of examples of information used in this embodiment. The categories 1020 of this information can be classified into unnecessary optical effects, the shape and position of the measurement target, detection of a moving object to be measured, composition ratios of constituent parts, activities that change over time, etc.

[0371] The summary 1022 of extracted information includes optical effects inside the object to be measured, optical effects on the surface of the object to be measured, optical effects along the light propagation path, shape contour information and characteristic information, moving object area, analysis of constituent materials in solids, content of substances in liquids, biological activity, etc.

[0372] 20C shows a list of disturbance noise causes 1036 and countermeasures 1038 for each measurement target area 1032 in the measurement object 22. The causes 1036 of electrical disturbance noise are the same regardless of the measurement target area 1032, and include shot noise, thermal noise, and electromagnetic induction noise.

[0373] In this embodiment, the electrical disturbance noise reduction method 1038 may involve band-limiting the detection signal to extract only the carrier component E1. Alternatively, in this embodiment, a lock-in amplifier E2 may be used. This lock-in amplifier E2 requires synchronization of the frequency and phase of a reference signal with the detection signal. Therefore, in this embodiment, various information included in the time-varying activity category 1020 in FIG. 20B may be used as the first extracted information 1004 to synchronize the frequency and phase.

[0374] In addition, an error correction function E3 for a digitized signal may be used as a countermeasure method for reducing electrical disturbance noise 1038. As a specific example, a technique such as PRML (Partial Response Most Likelihood) may be used to automatically correct the signal sequence to one that is considered to be the most appropriate.

[0375] The cause 1036 of optical disturbance noise differs slightly depending on the measurement target region 1032 within the measurement target 22. The effect of optical interference noise exists as a cause 1036 of optical disturbance noise that is common to both. The countermeasures for reducing this optical interference noise correspond to the technical details already explained in Chapters 2, 3, and 5.

[0376] The other optical disturbance noise generation cause 1036 is the inclusion of other optical effects. As a countermeasure against the inclusion of other optical effects, in this embodiment, the signal processing unit 42 performs arithmetic processing (signal processing or signal analysis) L3 between measurement signals to remove the influence of the inclusion of other optical effects.

[0377] The relationship between the processing procedure in this case and the processing procedure 1000 leading to the second information extraction already explained in FIG. 20A will be explained. 1. Acquisition of first information using detected light from the measurement object 22 In the processing procedure corresponding to the above, the process of extracting 1004 information based on other optical action results from the measurement signal acquired by the signal processing unit 42 from the measurement unit 8 or the signal receiving unit 40 corresponds to the first extracted information 1004. 2. Using the first information, a process for reducing optical or electrical disturbance noise in the detection signal is performed. This corresponds to a process of removing the component of the first extracted information 1004 from the measurement signal. 3. The acquisition of second information This corresponds to the second information extraction after the influence of other optical effects has been removed.

[0378] As a cause 1036 of optical disturbance noise that occurs according to a measurement target region 1032 within the measurement target 22, there is a cause 1036 that does not occur when measuring the overall characteristics of the entire measurement target 22, but occurs only when measuring local characteristics within the measurement target 22. As a cause 1030 of optical disturbance noise, there is the influence of disturbance light that mixes in from outside the local region that is the measurement target.

[0379] In this embodiment, as a method 1038 for reducing the influence of disturbance light entering from outside the local region to be measured, an aperture limit may be set at the imaging position or confocal position for the local region to be measured to block out unnecessary disturbance light L4. This makes it possible to prevent erroneous measurement of detected light from depth positions other than the local region to be measured as disturbance light, for example, when performing three-dimensional measurement of the inside of the measurement object 22.

[0380] Section 7.2 Various examples of application of lock-in amplification technology 21A shows an example of this embodiment. In the embodiment shown in FIG. 21A, first extracted information 1218 is extracted from a measurement signal obtained from the measurement unit 8 (or the signal receiving unit 40). The time-series spectral characteristic signal, time-series image signal, or data cube signal obtained from the measurement unit 8 in the optical device 10 is transferred to the signal receiving unit 40. As information extraction 1004 in the signal receiving unit 40, a predetermined time-series signal 1208 is partially extracted 1202 from this input signal.

[0381] The predetermined time-series signal 1208 partially extracted 1202 in the signal receiving unit 40 is transferred to the signal processing unit 42. Then, this signal processing unit 42 uses the predetermined time-series signal 1208 to extract a reference signal 1210. Then, further, the DC component is removed 1212 from this reference signal, and the form of only the AC component is used as first extracted information 1218.

[0382] In parallel with this, the time-series spectral characteristic signal, time-series image signal, or data cube signal transferred from the signal receiving unit 40 to the signal processing unit 42 is multiplied 1230 by the first extracted information 1218. Here, if the signal transferred to the signal processing unit 42 is a time-series spectral characteristic signal, multiplication is performed for each measurement wavelength. If the signal transferred to the signal processing unit 42 is a time-series image signal, multiplication is performed for each pixel. If a data cube signal is transferred, multiplication is performed for each measurement wavelength in each pixel.

[0383] The result of this multiplication is subjected to extraction 1236 of a time-series DC component for each wavelength or pixel by the action of an ultra-narrow band low-pass filter, and second extracted information 1018 is generated in the predetermined signal extraction unit 680. As an alternative method for processing the result of this multiplication, band limitation may be performed to extract E1 only the carrier component corresponding to the first extracted information 1218. However, extracting only the DC component by lock-in amplification E2 is more effective than extracting the carrier component E1 by band limitation, and the accuracy of the second extracted information 1018 is improved.

[0384] Fig. 21B shows another embodiment of this embodiment that is capable of reducing electrical disturbance noise. In Fig. 21A, first extracted information 1218 is extracted 1004 from a measurement signal from the measurement unit 8. In contrast, in the embodiment shown in Fig. 21B, first extracted information 1218 is extracted 1004 from a predetermined time-series signal 1208 obtained from the light emission amount control unit 30. For example, the output signal from the light emission amount output circuit 702 in Fig. 18B may be used as the predetermined time-series signal 1208 obtained from the light emission amount control unit 30.

[0385] For example, if measurement is performed in an environment where ambient light is likely to be present, the measurement accuracy will be significantly reduced due to the influence of the ambient light. In this case, the measurement accuracy will be significantly improved if the amount of predetermined light 230 emitted from light-emitting unit 2 is modulated and only the signal component corresponding to the modulated light is extracted as second extracted information 1018 in information extraction 1004, as shown in Figure 21B.

[0386] 21C shows, as an application example of Fig. 21B, a method for reducing electrical disturbance noise by irradiating pulsed light onto the measurement object 22. Here, the light emission intensity modulation signal 1228 sent from the signal processing unit 42 to the light emission intensity control unit 30 may take the form of a rectangular pulse waveform.

[0387] In the applied embodiment example of FIG. 21C , a reference pulse 1220 is generated in the time-varying component extraction processing unit 700 in the data processing block 630. A pulse counter 1222 generates a pulse once for each predetermined number of reference pulses 1220. The pulse output by this pulse counter 1222 is used as first extracted information 1218. This first extracted information 1218 is used as a light emission intensity modulation signal 1228 in a light emission intensity control unit 1228, and the amount of light irradiated onto the measurement object 22 changes in the form of a rectangular pulse in accordance with this light emission intensity modulation signal 1228. This first extracted information 1218 (the output pulse of the pulse counter 1222) is also simultaneously transferred to a multiplication circuit 1230 for each wavelength or each pixel. Thus, in the applied embodiment example shown in FIG. 21C , the same first extracted information 1218 is used simultaneously for multiple purposes.

[0388] The time-series spectroscopic characteristic signal, time-series pixel signal, or data cube signal obtained from the measurement unit 8 is detected in synchronization 1224 with a reference pulse 1220 generated in the time-varying component extraction processing unit 700, and transferred to a multiplication circuit 1230 for each wavelength or each pixel in the time-varying component extraction processing unit 700.

[0389] 21C , when the first extracted information 1218 has a pulsed rectangular waveform, the multiplication circuit 1230 for each wavelength or for each pixel can be configured with a very simple circuit. This multiplication circuit 1230 for each wavelength or for each pixel is configured only with an inverter (polarity inversion) circuit 1226 and a switch 1232. Then, in accordance with the first extracted information 1218 provided by the pulse counter 1222, the polarity of the signal sent to the time-series DC component extraction circuit (ultra-narrow-band low-pass filter) 1236 for each wavelength or for each pixel is switched (signal polarity switching synchronized with the first extracted information 1218 will be described later).

[0390] The application embodiment shown in FIG. 21C may also be used for length measurement and three-dimensional image measurement (three-dimensional video measurement). Light propagates through air at a speed of approximately 3×10 m / s, so light travels approximately 30 cm during a 1 nS pulse width period. The distance to the object 22 can be measured (length measurement) by measuring the time it takes for the light reflected from the surface of the object 22 located far away to return. For example, by using a pulse with a 1 nS pulse width and a 50% duty cycle as the reference pulse 1220 and measuring the change in reflected light intensity according to the pulse count value 1222, length measurement can be performed with a spatial distance resolution of 30 cm. Furthermore, by measuring the reflected light from the object 22 as an image signal using the image sensor 300, three-dimensional image measurement (three-dimensional video measurement) becomes possible.

[0391] Specifically, the reference pulse 1220 is fixed, and the light emission pulse amount (light emission amount modulation signal) 1223 from the light emission amount control unit 30 is controlled at an intermittent timing according to the pulse count value 1222. At the same time, the output signal 1200 for each pixel from the image sensor 300 is transmitted to the time-varying component extraction processing unit 700 in synchronization with the reference pulse 1220.

[0392] The length measurement method using laser pulses is applied to LiDAR (Light Detection and Ranging) used in autonomous driving vehicles. However, when conventional technology is used for image measurement, the measurement accuracy is significantly reduced due to the influence of speckle noise caused by the coherence of laser light. However, by combining this with the spatial interference noise reduction method explained in Chapter 12, high-precision length measurement and 3D image (video) measurement become possible.

[0393] Section 7.3 Structure of charge-storage signal receiver 22 is a diagram illustrating the characteristics of a case where a charge accumulation type signal receiving unit is used as the measurement unit 4. Most of the spectral characteristic signals, image signals, and data cube signals are not obtained continuously in time series, but are time-divided into a measurement period 1258 and a data transfer period 1254 (see FIGS. 23A(a) and 23B(a)). That is, during the measurement period 1258, measurement data is accumulated in the charge amount storage unit 1170. Then, during the data transfer period 1254, the accumulated data is transferred to the signal processing unit 42 via the data transfer unit 1180.

[0394] 22 shows an example of the principle of generating a spectroscopic characteristic signal using organic semiconductors. Each of the organic semiconductor layers 1102, 1104, and 1106 has a different absorption wavelength for the detection light 1100. In other words, the first organic semiconductor layer 1102, which is closest to the incident side of the detection light 1100, absorbs only the detection light 1100 in a predetermined wavelength range. Only the detection light 1100, which includes light of other wavelengths that has escaped absorption by the first organic semiconductor layer 1102, passes through the first organic semiconductor layer 1102. The second organic semiconductor layer 1104 absorbs the detection light 1100 in the other wavelength ranges among the light of other wavelengths that has escaped absorption by the first organic semiconductor layer 1102.

[0395] Each of the organic semiconductor layers 1102, 1104, and 1106 is sandwiched between a pair of transparent conductive films, and the transparent conductive films are further separated by transparent insulating layers 1124 and 1126. The arrangement of the transparent conductive films defines pixel regions 1152 and 1154. That is, the left side in the left diagram of FIG. 22 forms the first pixel region 1152, and the right side forms the second pixel region 1154.

[0396] When detection light 1100 within a predetermined wavelength range is absorbed in the organic semiconductor layers 1102, 1104, and 1106, charges are generated in the organic semiconductor layers 1102, 1104, and 1106, and these charges are used as detection signals. For example, when detection light 1100 is incident on the left side of the first organic semiconductor layer 1102 and is absorbed in the first organic semiconductor layer 1102, charges are generated in the first organic semiconductor layer 1102. Because the adjacent lower transparent conductive film 1112 in the first organic semiconductor layer 1102 is connected to the ground line, the charges generated in the first organic semiconductor layer 1102 enter the preamplifier 1150-6 via the transparent conductive film 1142.

[0397] The charge that enters preamplifier 1150-6 is stored in capacitor 1160-6 for a predetermined period (during measurement period 1258). As described above, a feature of charge accumulation signal receiver 40 is that charge is continuously stored in capacitor 1160-6 during the predetermined period (during measurement period 1258). The amount of charge stored in capacitor 1160-6 is transferred to charge storage unit 1170-2 at the end of the predetermined period, and then the charge is discharged. Thereafter, charge is stored again in capacitor 1160-6 during the next predetermined period (during measurement period 1258).

[0398] 12A or 12B21A, when the detection light is separated into each measurement wavelength using a spectroscopic element (blazed grating) 320, a line sensor or a two-dimensional array sensor is used for the image sensor 300. In this case, too, the measurement signal is output in a time-divided manner into a measurement period 1258 and a data transfer period 1254, as in FIG.

[0399] Therefore, this embodiment provides a detection signal band-limiting method E1 or lock-in amplification method E2, and a digitized signal error correction method E3, suitable for measurement signals in which the measurement period 1258 and data transfer period 1254 are time-shared (see the column of symbols 290 in FIG. 20C). When measuring using particularly weak detection light, the measurement period 1258 becomes relatively long, and the measurement accuracy using band-limiting E1 or lock-in amplification E2 is likely to decrease. In particular, when performing information extraction 1004 to extract first extracted information 1218 from a time-series spectroscopic characteristic signal, a time-series image signal, or a data cube signal obtained from the measurement unit 8 as illustrated in FIG. 21A, a relatively long measurement period 1258 tends to decrease the extraction accuracy of the first extracted information 1218.

[0400] Section 7.4 Example of signal processing for charge accumulation signals Figure 23A shows a method for extracting 1004 first extracted information 1218 with high accuracy over a relatively long measurement period 1258. Here, the lock-in amplifier circuit E2 described in Figure 21A is used.

[0401] Higher organisms have blood vessels running through their bodies. These blood vessels repeatedly expand and contract in accordance with pulsation (changes in blood flow 1252). When near-infrared light is irradiated around these blood vessels, the amount of near-infrared light absorbed changes over time in synchronization with the expansion and contraction of the blood vessels. FIG. 23A shows a processing method up to information extraction 1004, in which the change in the amount of near-infrared light absorbed in response to changes in blood flow 1252 is used as first extracted information 1218.

[0402] As shown in Fig. 23A(a), a measurement signal in which a measurement period 1258 and a data transfer period 1254 are time-shared is input to the signal processing unit 42. Fig. 23A(b) shows an example of the form of the time-shared measurement signal sent from the signal receiving unit 40. In Fig. 23A(b), the vertical axis represents blood flow 1252 obtained as a change in the amount of absorption of near-infrared light. The horizontal axis of Fig. 23 represents elapsed time 1250. As shown in FIG. 23A(b), during data transfer period 1254, no measurement signal is obtained from the charge accumulation type signal receiving unit (measurement unit 8). Therefore, as shown in FIG. 23A(b), only an intermittent, step-like measurement signal is obtained from measurement period 1258. As shown in FIG. 23A(c), the signal processing unit 42 converts this intermittent, step-like measurement signal into a continuous signal using a sample-and-hold method. At this stage, as shown in FIG. 23A(c), the measurement signal changes discontinuously in a step-like manner.

[0403] The measurement signal, which changes discontinuously in a step-like manner as shown in Fig. 23A(c), is smoothed using an optimized multiple parallel band-pass filter, and the DC component in the waveform of Fig. 23A(d) is further removed as shown in Fig. 23A(e), to generate first extracted information 1218.

[0404] FIG. 23B shows the signal processing (data processing) process up to information extraction 1004 of the second extracted information 1018 using the signal processing (data processing) method of FIG. 21A. FIG. 23B(a) shows an example of the form of a measurement signal sent from the signal receiving unit 40. A measurement period 1258 and a data transfer period 1254 are time-shared and transferred. FIG. 23B(b) shows time-series data for each measurement wavelength in the spectral characteristic signal or time-series data for each pixel in the image sensor, and time-series data 1200 for each measurement wavelength in the spectral characteristic signal for each pixel in the image sensor included in the data cube. Since the data transfer period 1254 is not measured, the data is sent as intermittent rectangular (pulse-like) time-series data.

[0405] FIG. 23B(c) shows the waveform of the first extracted information 1218 extracted by information extraction 1004 in FIG. 23A(e). FIG. 23B(d) shows the result of multiplication for each time series between FIG. 23B(b) and FIG. 23B(c). This waveform in FIG. 23B(d) matches the output waveform of the multiplication processing unit 1230 for each wavelength or pixel. Since there are periods in FIG. 23B(c) where the waveform takes on a "negative value," there are also periods in the waveform in FIG. 23B(d) where the waveform takes on a "negative value."

[0406] Figure 23B(e) shows the result of the second extracted information 1018 obtained by information extraction 1004 in Figure 21A. When the DC component of the discrete signal in Figure 23B(d) is extracted using the action of the time-series DC component extraction unit (ultra-narrow band low-pass filter) 1236 for each wavelength or each pixel in Figure 21A, a constant value independent of elapsed time 1250 as shown in Figure 23B(e) is obtained.

[0407] Section 7.5 Example of demonstration experiment results The results of measuring the spectroscopic characteristics of pulsating blood flow using the circuit configuration described in Figure 21A are described below. Figure 24A shows the optical arrangement within the light source unit 2 used for the measurement. The optical system described in Figure 4 and the optical system described in Figure 18A were combined using a dichroic mirror 350. Laser light with an emission wavelength of 1330 nm was used here.

[0408] An SI type multimode single-core fiber SF with a core diameter of 0.6 mm guided this combined light to the index finger tip 360. Another SI type multimode single-core fiber SF with a core diameter of 0.6 mm guided the light that had passed through the index finger tip 360 (scattered light within the index finger tip 360) to a spectrometer in the measurement unit 8.

[0409] 24B(a) shows the spectral characteristics of light irradiated onto the tip of the index finger 360. The amount of light emitted at the emission wavelength (1330 nm) of the laser light is overwhelmingly large. Note that the longer wavelength side of the light emitted from the halogen lamp HL is blocked by the dichroic mirror 350.

[0410] FIG. 24B(b) shows the spectral characteristics of the light transmittance of transmitted light that has passed through the tip 360 of the index finger (light that has been repeatedly scattered inside the tip 360 of the index finger and then exits from the opposite side of the tip 360 of the index finger). In terms of light transmittance, a sufficient amount of light was detected by the spectrometer even for 1330 nm wavelength light (laser light).

[0411] Figure 25A shows the change over time in relative light transmittance detected by a spectrometer. Here, the relative light transmittance is defined as the light transmittance obtained from actual measurement data divided by the time-unchanging light transmittance measured in advance in Figure 24B(b). This relative light transmittance is used on the vertical axis of Figure 25A. The horizontal axis of Figure 25A shows the passage of time in 0.1-second increments. Therefore, for every 10-second time lapse, one second elapses. Since a sufficient amount of light was detected with the 1330 nm wavelength light (laser light), the signal from this wavelength light can be used as the first extracted information 1218 (Figure 20A or Figure 21A).

[0412] Figure 25A(a) (top curve) shows the time change in relative light transmittance of 1330 nm wavelength light (laser light). When blood vessels expand in response to pulsation, the amount of light absorbed by water increases, causing a decrease in relative light transmittance. Figure 25A(a) shows a periodic change in light transmittance of around 1 second. This periodic change in light transmittance is thought to be synchronized with the pulsation.

[0413] As explained in Figure 10A, glucose (carbohydrate) has an absorption peak in the wavelength range of 0.9 μm to 1.0 μm. Similarly, proteins have an absorption peak in the wavelength range of 0.95 μm to 1.1 μm. Figure 25(b) (bold curve) shows the time change in relative light transmittance at a wavelength of 1026 nm, where the peptide backbone is expected to absorb light. Figure 25(c) (bottom curve) shows the time change in relative light transmittance at a wavelength of 928 nm, where glucose is expected to absorb light.

[0414] For ease of explanation, the raw signal waveform obtained from the measurement unit 8 is shown, rather than taking the form of the second extracted information 1018 in Fig. 21A. As is clear from a comparison of Figs. 25(b) and (c), the signal amplitude obtained from the 928 nm wavelength light is larger than the signal amplitude obtained from the 1026 nm wavelength light.

[0415] Figure 25B shows the results of adding measurement data for other wavelengths of light. In Figure 24B(b), the DC component of light transmittance is lowest at a wavelength of 971 nm. Therefore, Figure 25B(d) also shows the signal obtained from 971 nm wavelength light. The signal amplitude obtained from 971 nm wavelength light, where the DC component of the light transmittance was the smallest (Figure 25B(d)), is slightly larger than the signal amplitude obtained from 1026 nm wavelength light, where the DC component of the light transmittance was relatively large (Figure 25B(b)). From the above explanation, it can be seen that the amplitude of the change in relative light transmittance synchronized with the pulsation changes depending on the measurement wavelength.

[0416] Chapter 8: Combination of a light source unit and a measurement unit with a built-in image sensor Section 8.1 Internal structure of the image sensor and data acquisition timing in this embodiment Section 7.2 explained a length measurement method using a laser pulse. The amount of light that reaches a distant object is inversely proportional to the square of the distance from the light-emitting point. Therefore, when measuring a distant object, a sufficiently large amount of light is required. As a result, people near this light-emitting point are exposed to extremely strong laser light irradiation, increasing the risk of eye damage. To reduce the risk of eye damage, it is desirable to use near-infrared laser light for length measurement, as explained in Section 4.1.

[0417] 26A shows the structure of a (length measurement capable) 3D (dimensional) color image sensor 1280. Various optical filters 1272 to 1278 are arranged on the surface of each pixel 1262 to be imaged, and wavelength restrictions are imposed on light that can reach each pixel 1262 to be imaged.

[0418] That is, an optical filter 1272 that transmits only red light and near-infrared light is installed immediately before the pixels 1262-1-2 that detect red light and near-infrared light. An optical filter 1274 that transmits only green light and near-infrared light is installed immediately before the pixels 1264-1-2 that detect green light and near-infrared light. An optical filter 1276 that transmits only blue light and near-infrared light is installed immediately before the pixels 1266-1-2 that detect blue light and near-infrared light. Similarly, an optical filter 1278 that transmits only white light and near-infrared light is installed immediately before the pixels 1268-1-2 that detect white light and near-infrared light. Here, near-infrared laser light is used for length measurement using laser light.

[0419] 26B shows (the equivalent circuit of) the electronic circuit within this 3D color image sensor 1280. Preamplifiers 1150-1 and 1150-2 are connected to pixels 1262-1 and 1262-2, respectively, which detect red light and near-infrared light. Preamplifiers 1150-3 and 1150-4 are connected to pixels 1264-1 and 1264-2, respectively, which detect green light and near-infrared light. During the exposure period, charge is accumulated in capacitors 1160-1 to 1160-4 in accordance with the detection signals of each preamplifier 1150-1 to 1150-4.

[0420] Interlock switches 1300-1 and 1300-2 are turned ON / OFF independently and in conjunction with each other according to the exposure time and non-exposure time. The ON / OFF timing of these interlock switches 1300-1 and 1300-2 is controlled by exposure timing setting circuits 1292-1 and 1292-2. During exposure, interlock switches 1300-1 and 1300-2 are turned OFF independently, and charge is stored in capacitors 1160-1 to 1160-4 corresponding to preamplifiers 1150-1 to 1150-4. During non-exposure, interlock switches 1300-1 and 1300-2 are turned OFF independently, and detection signals from pixels 1262-1 and 1262-2 and 1264-1 and 1264-2 in the 3D color imaging element 1280 are released toward the ground line. At the same time, the charge stored in capacitors 1160-1 to 1160-4 is discharged.

[0421] Envelope detection circuits 1288-1 to 4 are individually connected to the preamplifiers 1150-1 to 4. Then, at the timing when exposure ends, the output voltages of the envelope detection circuits 1288-1 to 4 are temporarily stored in page memories 1296-1 and 2. Then, the output voltage data temporarily stored in the page memories 1296-1 and 2 is periodically transferred to the outside via a read circuit 1290.

[0422] 26B, the detection signal at each exposure timing is temporarily stored in page memories 1296-1 and 2. By arranging page memories 1296-1 and 2 that can store the detection signal at each exposure timing, it becomes possible to stably detect the detection signal for a very short exposure period.

[0423] Figure 26C shows the control timing of the exposure timing setting circuit 1292 in Figure 26B. The exposure period in Figure 26B (i.e., the period during which the preamplifier 1150 continues to transmit the detection signal from the pixel 1264 in the 3D color image sensor, which is a signal that has been charged and stored in the capacitor 1160, to the envelope detection circuit 1288) is defined as τ. Then, the connection of the interlock switch 1300 is interrupted (Figure 26C(b)) only during the time that elapses from time t1 to t1+τ (Figure 26C(a)).

[0424] 26C(c) shows the timing at which the output of the envelope detection circuit 1288 is captured into the page memory 1296. In this way, the output is captured into the page memory 1296 immediately after the end of the exposure period τ.

[0425] 26C(d) shows the output signal waveform of envelope detection circuit 1288 before and after the exposure period. Before the exposure period, the amount of charge accumulated in capacitors 1160-1 to 1160-4 is "0," so the output signal of envelope detection circuit 1288 remains at "0." Once the exposure period begins, charge begins to accumulate in capacitors 1160-1 to 1160-4, so the output signal of envelope detection circuit 1288 begins to increase. Immediately after the end of exposure period τ, the charge in capacitors 1160-1 to 1160-4 is discharged, but envelope detection circuit 1288 remains in the state it was in immediately before the end of exposure period τ.

[0426] Figure 26C (e) shows the data taken into the page memory 1296. The data in the page memory 1296 before the exposure period τ has an initial value of "0". Immediately after the end of the exposure period τ, the exposure timing setting circuit 1292 issues a data take-in instruction to the page memory 1296. At the timing of this data take-in instruction, the output data of the envelope detection circuit 1288 is taken into the page memory 1296. This taken-in data is passed to the readout circuit 1290 at the appropriate timing.

[0427] Section 8.2 Combination of a measurement unit with a built-in image sensor and a light source unit FIG. 27A shows an example embodiment of an optical system that combines a measurement unit 8 incorporating a 3D color image sensor 1280, as explained in the previous section 8.1, with a light source unit 2. As an example of the detailed structure of the light source unit 2 used here, a combination of FIGS. 18A and 18B may be used. Using the signal line 730 for synchronization with the outside in FIG. 18B enables highly accurate time coordination regarding the exposure period τ of the image sensor 1280. However, this is not limiting, and any light source unit 2 structure, including that shown in FIG. 9I, may also be used.

[0428] As explained in Section 5.4 using FIG. 17B, the amount of speckle noise is significantly reduced as the number of angle divisions in the optical property change element 210 increases. However, it is difficult to completely eliminate the amount of speckle noise. For this reason, in this embodiment, a structure that can be slightly moved in the direction of propagation of the light emitted from the light source unit 2 may be added. As explained in Section 5.1 using FIG. 13, the speckle noise pattern changes depending on the angle of irradiation onto the measurement object 22. Therefore, if the angle of irradiation onto the measurement object 22 is changed over time and the measurement results are time-averaged (or time-integrated), the amount of speckle noise can be further reduced.

[0429] 27A, a light reflecting plate 520 is placed midway along the optical path of the light emitted from the light source unit 2, and the tilt angle of the light reflecting plate 520 is slightly adjusted using piezoelectric elements 526 and 528. This causes the irradiation angle onto the measurement object 22 to change over time.

[0430] A half mirror 536 is placed within the measurement unit 8, and a portion of the reflected light from the measurement object 22 (not shown) reaches the 3D color image sensor 1280. An imaging lens movement mechanism 540 moves the imaging lens 144 along the optical axis direction. This imaging lens movement mechanism 540 allows the 3D color image sensor 1280 to be placed at an imaging position relative to the measurement object 22 located at an arbitrary position.

[0431] A two-dimensional array optical shutter 530 is installed at the same imaging position as the 3D color image sensor 1280. This two-dimensional array optical shutter 530 may be configured with any optical shutter, such as a liquid crystal shutter. Use of this two-dimensional array optical shutter 530 improves the measurement accuracy when near-infrared light is used for length measurement using the 3D color image sensor 1280.

[0432] As explained in Section 4.1 using Figure 10A, water absorbs near-infrared light. Water absorbs a large amount of light, especially light with wavelengths exceeding 1.3 μm. Therefore, in rainy or foggy environments, the accuracy of length measurements using near-infrared light decreases. In particular, when the surface of the measurement object 22 becomes wet, the amount of reflected near-infrared light from the surface decreases.

[0433] The following describes how the two-dimensional array optical shutter 530 is used. First, the amount of near-infrared light emitted from the light source unit 2 is set to "0," and a color image obtained from the measurement object 22 is measured using the 3D color image sensor 1280. The contours of the obtained color image are extracted, and the shape of the measurement object 22 observed with visible light is determined. Next, the near-infrared light emitted from the light source unit 2 is continuously emitted, and images obtained from the 3D color image sensor 1280 are collected. The water absorption distribution on the surface of the measurement object 22 can be determined by comparing the images with and without light emission from the light source unit 2. If a pattern that corrects the water absorption distribution on the surface of the measurement object 22 is provided to the two-dimensional array optical shutter 530, the influence of the water absorption distribution on the surface of the measurement object 22 can be reduced.

[0434] 27A, two-dimensional array optical shutter 530 is disposed within measurement unit 8, and light source unit 2 and measurement unit 8 are disposed in close proximity to each other. However, this is not limiting, and light source unit 2 and measurement unit 8 may be disposed at separate locations. For example, in FIGS. 31B, 30B, and 30C, which will be described later, light source unit 2 and measurement unit 8 are disposed at separate locations. In this case, light reflecting plate 520 including piezoelectric elements 526 and 528 and two-dimensional array optical shutter 530 may be built into light source unit 2.

[0435] 27B shows the control circuit configuration of the 3D color image sensor 1280. This control circuit configuration is used to not only reduce the influence of moisture absorption distribution on the surface of the measurement object 22, but also to achieve highly accurate length measurement. An emission timing control unit 1302 in the emission amount control unit 30 controls the emission amount of near-infrared light in the light source unit 2. A color image (video) storage unit 1316 when no light is emitted in the signal receiving unit 40 stores color images (video) collected by the 3D color image sensor 1280 in the measurement unit 8 when the light source unit 2 is not emitting light.

[0436] Next, the light emission timing control unit 1302 in the light emission amount control unit 30 controls the continuous light emission amount of near-infrared light in the light source unit 2. At the same time, the color image (video) storage unit 1318 including light of the light source wavelength in the signal receiving unit 40 stores the color image (video) collected by the 3D color imaging element 1280 at this time.

[0437] A difference calculation processing unit 1314 in the signal processing unit 42 extracts the difference between the color image (video) when the light source unit 2 emits light and when it does not. An image (video) storage unit 1312 for only the light source wavelength light in the signal processing unit stores the difference results. The stored contents are then transferred to a two-dimensional array optical shutter pattern setting unit 1304 in the light emission amount control unit 30. This two-dimensional array optical shutter pattern setting unit 1304 then controls the transmitted light amount distribution characteristics of the two-dimensional array optical shutter 530.

[0438] 27B also performs various timing controls, which will be described later in Figures 28A and onward. An exposure timing setting unit 1310 in the signal receiving unit 40 performs various timing controls, which will be described later. Simultaneously, a light emission timing control unit 1302 in the light emission amount control unit 30 controls the light emission timing of the light source unit 2 in accordance with commands from the system control unit 50.

[0439] 27B shows a structure in which the light source unit 2 and the measurement unit 8 coexist within the light source device 10. In this embodiment, the light source unit 2 and the measurement unit 8 may be located in physically separate locations and connected via the Internet. In this case, Internet communication may be performed between the light source unit 2 and the measurement unit 8 (via the host 50) using the method described in Section 6.4.

[0440] The measurement results obtained by combining the 3D color imaging element 1280 and the light source unit 2 are used by application software 58 that uses 3D color images (video) in the application field (various optical application fields) adaptation unit 60 (shown overlapping in FIGS. 1 and 27B). An example of how application software 58 that uses this 3D color image (video) will be described later in Chapter 9. However, it may be used for any service provision content, not just the service provision content described later in Chapter 9.

[0441] Also, in this Chapter 8, an embodiment example using a 3D color image sensor 1280 will be mainly described. However, this is not limiting, and any charge accumulation type signal receiving unit (including, for example, the contents described in Section 7.3) may be used as another embodiment example.

[0442] Section 8.3 Distance measurement procedure FIG. 28A shows a method for performing high-precision 3D color image (video) measurement. Note that the term "3D color image (video) measurement" is used here merely for convenience of explanation. Therefore, as an alternative embodiment to the embodiments described in Section 8.3 and the following Section 8.4, any combination of a charge-storage signal receiver and a light source 2 (including, for example, the contents described in Section 7.3) may be used. Furthermore, the procedure described in Section 8.3 may be used in conjunction with (performed before or after) the "correction process for the detected light characteristic distribution obtained from the measurement object 22 when irradiated with light of the emission wavelength of the light source 2" described in the previous Section 8.2.

[0443] 28A, a plurality of light emission patterns 750 (a plurality of light irradiation patterns for the measurement object 22) are used in the light source unit 2. The difference between these light emission patterns 750 may be notified to the light source unit 2 in advance using light emission pattern identification information 750 (FIG. 19C) in the control signal 790.

[0444] In this embodiment, it is possible to measure distances over a very wide range, such as a 100 m range or a 1 km range. It is difficult to measure distances over such a wide measurement range with high accuracy in one go. For example, it takes time to achieve high-accuracy measurement with a measurement error of 1 mm or less over the entire area of ​​a wide range, such as 1 km, in just one measurement. Furthermore, high measurement accuracy is required only in the vicinity of the location where the measurement object 22 is present. Conversely, high-accuracy measurement is not very meaningful in locations where the measurement object 22 is not present.

[0445] Therefore, one method is to first determine the approximate distance to the measurement object 22 over a wide range, and then perform highly accurate measurements near the measurement object 22. By dividing the measurement into multiple steps in this way and gradually changing the measurement range and measurement accuracy, the overall measurement efficiency improves. The optimal light emission pattern 750 may then be switched for each measurement range and required accuracy. By combining measurements using multiple light emission patterns 750 in this way, highly accurate measurements can be made even for measurement objects 22 located far away.

[0446] Three different light emission patterns 750 (multiple light irradiation patterns for the measurement object 22) may be used between the start (ST10) and end (ST17) of collecting a three-dimensional color image (video). In collecting a two-dimensional color image (video) in step 11, a light emission pattern described later in FIG. 28B(b) is used. Then, in step 12, the image (video) obtained from that light emission pattern is used to capture the reflected light pattern at the light source wavelength over the entire measurement distance range.

[0447] The next step, step 13, is to collect two-dimensional color images (video), using an illumination pattern described later in Fig. 28C(b). Then, in step 14, the image (video) obtained from the illumination pattern is used to capture the reflected light pattern at the light source wavelength for each measurement distance range.

[0448] The illumination pattern described later in Fig. 28D(b) is used to collect two-dimensional color images (video) in the subsequent step 15. Then, in step 16, detailed distance measurements are performed for each measurement distance range using the images (video) obtained from the illumination pattern.

[0449] Figure 28B shows a method for capturing an image of the reflected light pattern at the light source wavelength over the entire measurement distance range. The intensity of light emitted from a single light-emitting point is inversely proportional to the square of the distance from the light-emitting point. When measuring the distance to the measurement object 22 using reflected light from the measurement object 22, the distance from the light source unit 2 to the measurement unit 8 is twice the distance to the measurement object 22. Therefore, the maximum light emission intensity of the light source unit 2 is determined by the measurement range (the maximum distance from the light source unit 2 that can be measured). Furthermore, as the position of the measurement object 22 moves away, it is necessary to increase the light emission intensity of the light source unit 2.

[0450] Figure 28B(b) shows an appropriate light emission pattern for capturing the total reflection light pattern across the entire measurement distance range. Light is emitted continuously from time t1 to time t2, and the light intensity is reduced along a quadratic curve over time. This allows for the collection of uniform light reflection characteristics across the entire measurement distance range.

[0451] FIG. 28B(c) shows the exposure timing within the measurement unit 8 (3D color image sensor 1280). Immediately after the light source unit 2 stops emitting light at time t2, exposure occurs for a period of τ (rectangular wave period). During this exposure period τ, light that left the light source unit 2 only Δt1 or Δt2 earlier returns. Regarding the measurement distance Δx, there is a relationship of Δx=cΔt / 2 (c: speed of light in air). Therefore, the measurement distance range in this case is up to a distance of c(t2-t1) / 2. In FIG. 28B(c), The image acquired at the exposure timing reveals the total reflection light pattern across the entire measurement distance range. By comparing the image acquired here (the total reflection light pattern across the entire measurement distance range) with the image acquired in Figure 28C, which will be described later, it is possible to determine the approximate distance for each small area within the total reflection light pattern across the entire measurement distance range. Note that all images acquired in the explanations from Figure 28B to Figure 28E refer to images stored in image (video) storage unit 1312 for light source wavelength only within signal processing unit 42, shown in Figure 27B.

[0452] Figure 28C shows a method for capturing an image of a reflected light pattern using light of the light source wavelength for each measurement distance range. The light source unit 2 emits intermittent pulses, as shown in Figure 28C(b). This intermittent pulse emission occurs at a fixed cycle of times t1, t2, and t3. An interference prevention period 798 of a predetermined duration is provided within this fixed cycle, and light from the light source unit 2 is controlled not to emit light during this interference prevention period 798. Controlling the light emission to be non-emission during this interference prevention period 798 prevents erroneous distance measurements due to pulse emission at the wrong time, improving measurement accuracy.

[0453] The light emission intensity is also changed for each of the light emission timings t1, t2, and t3. The phenomenon of a decrease in the amount of detected signal from a distant measurement object 22 has been explained above. By changing the light emission intensity for each desired measurement distance range in this way, changes in measurement accuracy for each measurement distance range are prevented, enabling stable distance measurement across the entire measurement distance range.

[0454] Figure 28C(b) shows a rectangular pulse emission state. However, this is not limiting and light emission may be induced by a "modulation signal specific to the light source unit 2 (ID information signal of the light source unit 2)" during the pulse emission period. In a system in which multiple light-emitting units 2 are arranged in the same location, there is a risk that the light emission state from different light-emitting units 2 will be erroneously detected within the measurement unit 8 (3D color image sensor 1280). A separate photodetector 250 may be arranged within the measurement unit 8, and this separate photodetector 250 may simultaneously detect a unique modulation signal (ID information signal of the light source unit 2) that is different for each light source unit 2. By using this in combination with the detection of a modulation signal specific to the light source unit 2 using the separate photodetector 250, it is possible to detect unwanted light emission pulses from other light-emitting units 2 during the exposure period τ within the target measurement unit 8. This significantly reduces the risk of erroneous detection in a system in which multiple light-emitting units 2 are arranged in the same location.

[0455] FIG. 28C(c) shows the exposure timing within the measurement unit 8 (3D color image sensor 1280). The delay times Δt1, Δt2, and Δt3 of the exposure timing within the measurement unit 8 (3D color image sensor 1280) relative to the light emission timing of the light source unit 2 are different for each of the light emission times t1, t2, and t3. The measurement distance range is switched by changing this delay time. In FIG. 28C, Δt1<Δt2<Δt3. However, this is not limiting, and as long as there is a difference of a certain value or more between the delay times Δt1, Δt2, and Δt3, each delay time may be set arbitrarily. It may be set as Δt1>Δt2>Δt3.

[0456] Each image acquired at each timing for the same exposure period τ shows a portion of the image acquired in Fig. 28 B. Therefore, by comparing each image acquired here with the image acquired in Fig. 28 B, it is possible to grasp the approximate distance for each finely divided region within the total reflection light pattern across the entire measurement distance range.

[0457] Fig. 28D shows a detailed distance measurement method within each measurement distance range. The details of setting the interference prevention period 798 in the light emission state of the light source unit 2 (Fig. 28D(b)) and the details of changing the delay times Δt1 and Δt2 of the exposure period τ for each light emission time t1 and t2 of the light source unit 2 (Fig. 28D(c)) are consistent with Fig. 28C.

[0458] As shown in Figure 28D(b), the part where the light source unit 2 emits light intermittently is different from that in Figure 28C(b). During the intermittent light intensity modulation period in Figure 28D(b), "uniform cycle light emission" is desirable. Furthermore, during this light intensity modulation, a "duty ratio of 50%" is desirable. As long as this light emission state satisfies the conditions of "uniform cycle" and "duty ratio of 50%," light may be emitted with any waveform. For example, a sine wave, square wave, triangular wave, or other waveforms may be freely set.

[0459] Figure 28E is an explanatory diagram of a distance measurement method using phase detection. The internal structure of the 3D color image sensor 1280 was explained using Figure 26A. For distance measurement here, four pixel sets 1262-1, 1264-1, 1266-1, and 1268-1 are used. Furthermore, the exposure timing of each pixel is shifted in accordance with the modulated light emission state of the light source unit 2.

[0460] 28E(b) to (e) show the exposure timing for each of the four pixels 1262, 1264, 1266, and 1268. Here, the exposure periods τ for the four pixels 1262, 1264, 1266, and 1268 are all set to the same value. The exposure timings are shifted by the exposure period τ. Then, as shown in FIG. 28E(f), the modulated light emission cycle of the light source unit 2 is set to "4τ".

[0461] When the detected light in Figure 28E(g) is shifted by a phase φ from the reference modulated light emission state in Figure 28E(f), the amount of signal input from the four pixels 1262, 1264, 1266, and 1268 to the page memory 1296 (Figure 26B) corresponds to the area values ​​of A1, A2, A3, and A4. Therefore

[0462]

number

[0463] For example, by using the technology of Patent Document 3, it is now possible to capture images with an exposure period τ as short as 1 nS. The period of the reference modulated light emission in Figure 28E(f) is 4τ = 4 nS. The speed of light in air is approximately 3 × 10 8 m / s, and considering that light is to be detected going back and forth to the measurement object 22, the above period is 3×10 8 x4x10 -9 ÷ 2 = 0.6 m. Therefore, with an exposure period τ = 1 nS, it is possible to measure forward and backward position changes within a measurement distance range of 60 cm. In this case, the measurement accuracy is determined by the area accuracy of areas A1 to A4 in Figure 28E(g). For this reason, the optical noise reduction techniques explained in Chapters 2, 3, and 5 become extremely important.

[0464] Section 8.4: How to reduce the impact of laser speckle noise on measurements The method described in 1. above significantly reduces speckle noise. However, as shown in Figure 17B, it is difficult to completely eliminate speckle noise even if the number of angular divisions of the optical property change element 210 is significantly increased. In Chapter 7, we explained a high-precision measurement method that combines optical noise reduction technology and circuit technology.

[0465] 28F shows a method for further reducing the effects of speckle noise by combining circuit technologies. This assumes that optical noise reduction measures, such as those described in Chapter 7 in the light source unit 2, those described in Section 8.2 using FIG. 27A, and those described in Section 3.3 using FIG. 9I, have been implemented. However, this is not limiting, and the following embodiment may be implemented without optical noise reduction.

[0466] Figure 27F(b) shows the light emission state of the light source unit 2. The pulsed light emission described in Figure 28C(b) begins at time t2. However, as described using Figure 28C(b), light emission modulation may be performed during this pulsed light emission period. From the subsequent time t4, modulated light emission described in Figure 28D(b) is performed.

[0467] The detection unit 8 (3D color imaging element 1280) has an exposure period τ with different timing. Signals detected during the exposure periods τ with different timings are stored as separate signals in the page memory 1296 (FIG. 26B). For simplicity of explanation, FIGS. 28F(c) to 28F(e) show only the exposure period τ corresponding to only one pixel 1262. However, in reality, as shown in FIGS. 28G and 28H, the exposure start times for each of the pixels 1262 to 1268 are shifted by the exposure period τ.

[0468] FIG. 27F(c) shows the timing of the first exposure period τ in the detection unit 8 (3D color imaging element 1280 thereof). This first exposure period τ starts at time t1, before the light source unit 2 emits light. During this first exposure period τ, a color image (video) using only visible light is captured when the light source unit 2 is not emitting light. The image (video) obtained here matches the content of the image (video) stored in the color image (video) storage unit 1316 when no light is emitted, as shown in FIG. 27B.

[0469] FIG. 27F(d) shows the timing of the second exposure period τ in the detection unit 8 (3D color imaging element 1280 thereof). This second exposure period τ begins at time t3, which is delayed by Δt0 from time t2 when the light source unit 2 starts emitting pulsed light. During this second exposure period τ, an image (video) is obtained in which a color image (video) obtained from visible light is superimposed with a reflected image (video) of the emission wavelength light of the light source unit 2 irradiated by pulsed emission. This image (video) matches the content of the image (video) stored in the color image (video) storage unit 1318 containing light source wavelength light in FIG. 27B.

[0470] The second exposure period τ begins in the detection unit 8 (3D color image sensor 1280) Δt0 after the light source unit 2 starts emitting pulses. This time difference Δt0 means that a reflected image (video) of the light with the wavelength emitted by the light source unit 2 at a position away by Δx0 = cΔt0 / 2 is superimposed. The actual pulse emission period of the light source unit 2 is much longer than the second exposure period τ in the detection unit 8 (3D color image sensor 1280). Therefore, at the location where the reflected image (video) of the light with the wavelength emitted by the light source unit 2 is superimposed, a reflected image (video) of the light with the wavelength emitted by the light source unit 2 at a position away by Δx0 = cΔt0 / 2 - δ, which is δ shorter than Δx0 = cΔt0 / 2, is superimposed.

[0471] The important thing here is that "speckle noise is mixed into the reflected image (video) of the light emitted at the wavelength of the light source unit 2." The speckle noise mixing rate differs between the four pixels 1262, 1264, 1266, and 1268 that make up one set. During this second exposure period τ, an image (video) mixed with speckle noise is acquired for each of the pixels 1262 to 1268.

[0472] The areas A1 to A4 shown in FIG. 28E(g) represent an ideal state without speckle noise. However, in reality, the influence of speckle noise (the rate of change in light intensity caused by speckle noise) differs for each of the pixels 1262 to 1268. Therefore, when the influence of speckle noise is taken into account, the levels of A1 to A4 in FIG. 28E(g) vary significantly individually due to the influence of speckle noise. Here, within a very short time range, the influence of speckle noise for each of the pixels 1262 to 1268 (the rate of change in light intensity caused by speckle noise) is constant regardless of the light emission intensity of the light-emitting unit 2. In other words, the influence of speckle noise for each of the pixels 1262 to 1268 (the rate of change in light intensity caused by speckle noise) is considered to be approximately equal when the light emission pattern of the light-emitting unit 2 is in a modulated light emission state as shown in FIG. 28E(f) and when the light emission intensity of the light-emitting unit 2 is constant over time.

[0473] When viewed over a short exposure period τ within the pulse emission period having a square wave, it can be considered that a constant amount of light is emitted during that exposure period τ. Therefore, in this embodiment, the "speckle noise influence rate (light intensity fluctuation rate caused by speckle noise) for each of the pixels 1262 to 1268" acquired during the second exposure period τ in the detection unit 8 (3D color image sensor 1280) is considered to be the first extracted information (FIG. 20A), and this first extracted information is used to extract second information corresponding to "phase information obtained from the measurement object 22."

[0474] Figure 27F(e) shows the timing of the third exposure period τ in the detection unit 8 (3D color image sensor 1280). This third exposure period τ begins at time t5, which is delayed by Δt0 from time t4, when the light source unit 2 begins modulated emission. For ease of illustration, the interval between times t3 and t4 in Figure 28F is narrow. However, in reality, the interval between times t3 and t4 is sufficiently wide. During this third exposure period τ, an image (video) is obtained in which a color image (video) obtained from visible light is superimposed with a reflected image (video) of the light emitted by the light source unit 2 using modulated emission. This reflected image (video) of the light emitted by the light source unit 2 contains "phase component information obtained from the measurement object 22." Furthermore, this "phase information obtained from the measurement object 22" is buried in the "speckle noise for each pixel 1262 to 1268." Therefore, by utilizing the first extracted information acquired during the second exposure period τ, namely, the "speckle noise influence rate for each pixel 1262 to 1268 (the rate of fluctuation in light intensity caused by speckle noise)," the "phase component information obtained from the measurement object 22" (second information) buried in the speckle noise is extracted 1000 (Figure 20A).

[0475] FIG. 28G shows the detection signals obtained for each pixel during the first and second exposure periods. FIGS. 28G(b)-(e) show the detection signals obtained during the first exposure period τ by a set of four pixels 1262-1268. The red intensity b1, blue intensity b2, green intensity b3, and white intensity b4 in the color information collected during the first exposure period τ are obtained individually. The exposure periods τ for each of the four pixels 1262-1268 are shifted by τ.

[0476] 28G(f)-(i) show detection signals obtained by four pixels 1262-1268 constituting one set during the second exposure period τ. Here again, the exposure period τ is shifted by τ for each of the four pixels 1262-1268. When there is no speckle noise, the reflected light amount Δhi (1≦i≦4) for the emitted wavelength light of the light source unit 2, which is added to each color intensity bi (1≦i≦4) in the color information, shows approximately the same value. However, when there is significant speckle noise, the reflected light amounts Δh1, Δh2, Δh3, and Δh4 added for each of the four pixels 1262-1268 differ significantly.

[0477] FIG. 28H shows the detection signals for each pixel obtained during the second and third exposure periods. FIGS. 28H(f)-(i) correspond to FIGS. 28G(f)-(i). FIGS. 28H(j)-(m) show the detection signals obtained during the third exposure period τ by four pixels 1262-1268 constituting one group. The exposure periods τ for each of the four pixels 1262-1268 are also shifted by τ. The phase component information obtained from the measurement object 22 in response to the modulated light emitted from the light source unit 2 has values ​​ΔL1, ΔL2, L3, and ΔL4 embedded in speckle noise, which are added to the color intensities bi (1≦i≦4) in the color information.

[0478] When the time difference t5-t3 between the start time t3 of the second exposure period τ and the start time t5 of the third exposure period τ is sufficiently small, the "speckle noise influence rate (light intensity fluctuation rate caused by speckle noise) for each pixel 1262 to 1268" is considered to be approximately the same between ΔLi and Δhi (1≦i≦4). Then, the substantial phase component Ai from which the influence of speckle noise has been removed is It can be calculated as Ai = ΔLi / Δhi (1 ≦ i ≦ 4). In this way, by using the first extracted information (the speckle noise influence rate for each pixel 1262 to 1268 (the light intensity fluctuation rate caused by speckle noise)) obtained during the second exposure period τ, the second information (the actual phase component Ai) mixed in the signal obtained during the third exposure period τ can be extracted. This method can further remove the influence of residual noise (such as remaining speckle noise) after the optical noise reduction described in Chapters 2, 3, and 5.

[0479] Section 8.5 Hyperspectral detection method using irradiation wavelength control 29A shows the basic cross-sectional structure of a linear variable bandpass filter 190. The thickness of an optical thin film 194 formed on a transparent substrate 192 varies depending on the location. When panchromatic light (light containing light of different wavelengths) 188 is incident on this linear variable bandpass filter 190, it is multiple-reflected between the surface of the optical thin film 194 and the interface between the transparent substrate 192. As a result, the wavelengths of transmitted light 198-1 to 198-4 vary depending on the location.

[0480] 29B shows an example embodiment of a hyperspectral detection method that combines this linear variable bandpass filter 190 with a 3D color image sensor 128 having the structure of FIG. 26A. A linear variable bandpass filter moving mechanism 196 moves the linear variable bandpass filter 190 over time. As a result, the wavelength of light that passes through pinhole 310, which is placed at the focusing position of focusing lens 330, changes over time.

[0481] The light that passes through this pinhole 310 illuminates the measurement object 22 (not shown) via the imaging lens 144. A portion of the light reflected from the measurement object 22 is reflected by the half mirror 536 and directed toward the 3D color image sensor 128. An imaging lens moving mechanism 540 moves the imaging lens 144 in the optical axis direction, and aligns the position of the 3D color image sensor 128 with the imaging position of the measurement object 22.

[0482] The light source unit 2 emits panchromatic light intermittently. The 3D color image sensor 128 collects color images of the measurement object 22 during periods when the light source unit 2 is not emitting light. Furthermore, during periods when the light source unit 2 is emitting light, the 3D color image sensor 128 collects images in which the color image and a reflected light image of wavelength light that passes through the linear variable bandpass filter 190 are superimposed. The differential light intensity between the two images becomes a hyperspectral data cube signal.

[0483] 29B, near-infrared spectral characteristics for each pixel can be acquired simultaneously with the color image, eliminating the need for alignment between the color image and the hyperspectral data cube image, improving user convenience.

[0484] For example, a thermal radiation filament such as a halogen lamp or mercury lamp may be used as the light-emitting unit 470 in the light source unit 2 that emits panchromatic light. However, because the electrical response speed inside the thermal radiation filament is slow, it is difficult to achieve high-speed intermittent light emission.

[0485] As a light source unit 2 structure capable of emitting panchromatic light with high-speed response, an improved version of the structure shown in FIG. 11A will be described as an example of this embodiment. The emission wavelength of the semiconductor laser element 500 used as the second light source 170 is set to 1250 nm or less and is used as an excitation light source for the near-infrared light-emitting phosphors 162 and 164. In this case, the first light source 160 (LED light source) may be omitted from the light-emitting unit 470. The fluorescent substances 182 to 186 used in the near-infrared light-emitting phosphors 162 and 164 are materials with short fluorescence half-lives (materials that fluoresce immediately after excitation and stop emitting fluorescence immediately after the excitation light irradiation is stopped). By selecting the appropriate material, a light-emitting unit 470 with a high-speed fluorescence response can be realized.

[0486] The method for extracting light of a predetermined wavelength from panchromatic light emitted from the light source unit 2 is not limited to using the linear variable bandpass filter 190. Light of a predetermined wavelength may be extracted from panchromatic light by any method, such as a general optical filter, a tunable Fabry-Verot resonator, or mechanically tilting the spectroscopic element 320.

[0487] When the light source unit 2 having the above structure is arranged as shown in FIG. 29B and operated in conjunction with the 3D color image sensor 1280 using the method described in Sections 8.1 to 8.4, it is possible to measure the near-infrared spectral characteristics of the measurement object 22 and simultaneously measure the surface irregularities of the measurement object 22 in three dimensions. In other words, by controlling the light emission of the light source unit 2 in conjunction with the control unit 8 and controlling the wavelength of the light emitted from the light source unit 2, it is possible to simultaneously measure the spectral characteristics of the measurement object 22 and the distance to the measurement object 22. Furthermore, by performing the above measurements for each pixel arranged two-dimensionally (or one-dimensionally), it is possible to simultaneously measure multiple different positions on the measurement object 2. Furthermore, as described in Section 4.4, it is possible to miniaturize the light source unit 2 or the measurement unit 8. This results in an extremely compact structure that makes it easy to collect a variety of information at once.

[0488] Chapter 9 Service Provision Section 9.1 Examples of input / output device configurations when providing services 30A is an explanatory diagram of examples of input devices and output devices required for using a predetermined service providing domain. As an example of an embodiment of a method for providing a service to a user or a system for providing a service to a user, there is a method of constructing a predetermined service providing domain 1058 in cyberspace and allowing the user to use it.

[0489] In order for the user 1080 to use a predetermined service providing domain 1058 in the cyberspace, the end user 1080 needs an input device 1060 and an output device 1070 necessary for using the predetermined service providing domain 1058 in the cyberspace.

[0490] In personal computers, keyboards and mice are primarily used as input devices 1060. In smartphones, touch screens correspond to the input device 1060. Touch screens offer greater functional diversity than keyboards. In this embodiment, automatic image (video) input technology and automatic voice input technology may be used as input methods that offer greater functional diversity, operability, and convenience than touch screens. That is, in this embodiment, the device classification 1062 for the input device 1080 uses an image (video) collection function and a voice information collection function. A microphone is an input device form 1064 that collects this voice information. In addition, the 3D color camera 1280 described in Chapter 8 and a visible color camera that can simultaneously measure near-infrared spectral characteristics can be used as input device form 1064 with an image (video) collection function.

[0491] When a 3D color camera 1280 or a visible color camera capable of simultaneously measuring near-infrared spectral characteristics is used as the input device 1080, the user's body movements can be used (data use purpose 1068) as a method of inputting information. For example, the user's gestures or finger movements (finger actions) can be used instead of an existing mouse. In this case, the input device 1060 or the host 50 connected to the input device may be provided with a gesture interpretation function, a fingertip command interpretation function, and a virtual three-dimensional rendering function.

[0492] When a visible color camera capable of simultaneously measuring near-infrared spectral characteristics is used as the input device 1060, information input allows for analysis of the biological composition that appears in the near-infrared spectral characteristics. Therefore, it may be used for personal authentication using biometric information, such as vein authentication. Furthermore, biological activity can be automatically detected from temporal changes in the near-infrared spectral characteristics. For example, the host 50 can automatically recognize the emotions and feelings of the end user 1080 from the contraction status of the facial muscles of the end user 1080. Furthermore, as described in Section 7.5, the composition of the end user's 1080's blood may be analyzed non-invasively or contactlessly from the outside. For example, the user's physical condition can be automatically input using blood glucose level measurement results. Furthermore, the adrenaline content in the blood can be used to input the end user's 1080's excitement level in real time.

[0493] The output device classification 1062 based on the functions that can be realized by the output device 1070 includes a three-dimensional display function, a modeling function, an audio information output function, a tactile stimulation device function, and the like. A function for restricting movement of the end user 1080 may be included as part of this tactile stimulation function. For example, when the end user 1080 carries a heavy load in the real world, the degree of freedom of movement is restricted. This restriction on the degree of freedom of movement that the end user 1080 experiences when entering a predetermined service providing domain 1058 in cyberspace may be implemented as part of this tactile stimulation device function.

[0494] As an output device form 1074 that realizes the above-mentioned three-dimensional display function, a thin stationary display screen or a portable display device such as VR (virtual reality) or AR (augmented reality) may be used. Also, a 3D printer may be used as an output device with a modeling function. A speaker can be used to output audio information, and a skin epidermal pressure device has a tactile stimulation function.

[0495] 30B and 30C show an input device 1060 and an output device 1070 used in this embodiment. In FIG. 30B, a thin, stationary display screen (a wall-mounted 3D display or a 3D display for computer display) 900 is used as an example embodiment of the output device 1070 used as the display unit 18. Furthermore, one light source unit 2 and multiple measurement units 8 are arranged in a part of this thin, stationary display screen 900 or in a part of its outside (the outer frame of the wall-mounted 3D display or the 3D display for computer display) 902. This set of one light source unit 2 and multiple measurement units 8 corresponds to the input device 1060. FIG. 30B uses the example embodiment of the light source unit 2 and measurement units 8 described up to Chapter 8. In particular, by arranging multiple measurement units 8 in different positions, it is possible to collect 3D images (3D videos) from multiple angles.

[0496] Lenticular lenses (fine cylindrical lenses) are arranged horizontally on the surface of the thin, stationary display screen (wall-mounted 3D display or computer-displayed 3D display) 900. A measurement unit 8 measures the three-dimensional position of the end user's 1080 eyeballs in real time. Then, according to the eyeball position of the end user 1080 (eye tracking), an image for the right eye and an image for the left eye of the end user 1080 are created individually for each pixel on the thin, stationary display screen (wall-mounted 3D display or computer-displayed 3D display) 900. The lenticular lenses also control the direction in which the right-eye image and the left-eye image face the right and left eyes of the end user 1080. A virtual 3D image is then displayed to the end user 1080 by utilizing the difference in the convergence angle between each image, which has a different virtual position in the front-to-back direction as perceived by the right eye and the left eye.

[0497] The virtual keyboard seen in the foreground in Fig. 30B shows an example of display using the above method. Furthermore, three-dimensional measurement can be performed by the combined operation of the light source unit 2 and the measurement unit 8. Therefore, the three-dimensional positions of each of the ten fingertips of the end user 1080 can be measured in real time. For example, when the end user 1080 places both hands on the three-dimensionally displayed virtual keyboard and moves his or her ten fingers, virtual key-in operation becomes possible.

[0498] 30C shows another embodiment of the input device 1060 and the output device 1070. As an embodiment of the output device 1070 corresponding to the display unit 18, AR glasses 820, 830 capable of stereoscopic display are used. These AR glasses 820, 830 separately display an image (video) for the right eye and an image (video) for the left eye, and use the difference in convergence angle described above to provide a stereoscopic display. Note that VR glasses may be used instead of the AR glasses 820, 830.

[0499] FIG. 30C(b) shows an example in which a virtual keyboard placed at a position a predetermined distance away from the end user 1080 is displayed as a stereoscopic display screen (image). The end user 1080 looks at this virtual keyboard and types on the virtual keyboard while moving ten fingers. A brooch 810 with a built-in 3D color imaging element fixed to the breast pocket of the end user 1080 has a light source unit 2 and a measurement unit 8, and light emitted from the light source unit 2 is reflected by the fingertips of the end user 1080. The measurement unit 8 uses the light reflected from the fingertips to measure a 3D color image (image) including the three-dimensional positions of the ten fingertips in real time.

[0500] An end user 1080 carries a backpack 850 that has a built-in power supply unit, a control unit 50, and a communication function for communicating with the outside. The backpack 850 supplies power to the AR glasses 830 (display unit 18) via a connection cable 866. The backpack 850 also generates an image (video) for the right eye and an image (video) for the left eye, and transmits them to the AR glasses 830 via the connection cable 866.

[0501] At the same time, the backpack 850 supplies power to the brooch 810 with a built-in 3D color image sensor via a connection cable 866. The measurement unit 8 also transmits the 3D image (3D video) collected by the measurement unit 8 to the backpack 850 via a connection cable 876. The signal processing unit 42 in the backpack 850 analyzes the 3D image (3D video) and estimates the movements of the end user's 1080's ten fingertips. These estimation results are then used to determine the position within the virtual keyboard where the end user 1080 has typed in. In this way, if 3D measurement can be performed in real time using the 3D color image sensor 1280, various information ca...

Claims

1. In a light source unit composed of a light emitting unit and a predetermined optical member, the light-emitting unit has a first light-emitting source and a second light-emitting source, the first emitted light from the first light source travels toward the predetermined optical member in a divergent state; the second emitted light from the second light source also travels toward the predetermined optical member in a divergent state; the predetermined optical member through which the first radiation light and the second radiation light pass has minute steps or minute discontinuities in its surface; a first light included in the first emitted light travels through a first optical path related to the predetermined optical member; a second light included in the first emitted light travels along a second optical path related to the predetermined optical member; the light source unit disposes the predetermined optical member so that a first optical path difference between the first optical path and the second optical path exceeds a coherence length; generating a first predetermined light by adding the intensities of the first light and the second light having the first optical path length difference at a predetermined location; a third light included in the second emitted light travels through a third optical path related to the predetermined optical member; a fourth light beam included in the second emitted light beam travels through a fourth optical path related to the predetermined optical member; the light source unit disposes the predetermined optical member so that a second optical path length difference between the third optical path and the fourth optical path also exceeds the coherence length; generating a second predetermined light by adding the intensities of the third light and the fourth light having the second optical path length difference at the predetermined location; a light source unit that radiates the first predetermined light and the second predetermined light toward the outside of the light source unit;

2. the predetermined optical member has a function of a lens having a minute step or a minute discontinuous portion of a curved surface on a light incident surface or a light exit surface, 2. The light source unit according to claim 1, wherein the first predetermined light and the second predetermined light are condensed at a predetermined position.

3. In an optical device consisting of a light source unit and a measurement unit, the light source unit includes a light emitting unit and a predetermined optical member; the light-emitting unit has a first light-emitting source and a second light-emitting source, the first emitted light from the first light source travels toward the predetermined optical member in a divergent state; the second emitted light from the second light source also travels toward the predetermined optical member in a divergent state; the predetermined optical member through which the first radiation light and the second radiation light pass has minute steps or minute discontinuities in its surface; a first light included in the first emitted light travels through a first optical path related to the predetermined optical member; a second light included in the first emitted light travels along a second optical path related to the predetermined optical member; the light source unit disposes the predetermined optical member so that a first optical path difference between the first optical path and the second optical path exceeds a coherence length; generating a first predetermined light by adding the intensities of the first light and the second light having the first optical path length difference at a predetermined location; a third light included in the second emitted light travels through a third optical path related to the predetermined optical member; a fourth light beam included in the second emitted light beam travels through a fourth optical path related to the predetermined optical member; the light source unit disposes the predetermined optical member so that a second optical path length difference between the third optical path and the fourth optical path also exceeds the coherence length; generating a second predetermined light by adding the intensities of the third light and the fourth light having the second optical path length difference at the predetermined location; An optical device that irradiates an object (20) with the first predetermined light and the second predetermined light, and detects the first predetermined light and the second predetermined light obtained from the object (20) with the measuring unit.

4. The predetermined optical member has minute steps or minute discontinuities in the surface, the light source unit includes a first light source and a second light source; directing a first emitted light from the first light source in a divergent state toward the predetermined optical member; the second emitted light from the second light source is also directed toward the predetermined optical member in a divergent state; causing first light and second light included in the first radiation light to travel through different optical paths; the predetermined optical member acts so that a first optical path difference between the first light and the second light exceeds a coherence length; generating a first predetermined light by adding the intensities of the first light and the second light after passing through the predetermined optical member at a predetermined location; causing third light and fourth light included in the second radiation light to travel through different optical paths; the predetermined optical member acts so that a second optical path difference between the third light and the fourth light exceeds the coherence length; generating a second predetermined light by adding the intensities of the third light and the fourth light after passing through the predetermined optical member at the predetermined location; A predetermined light utilization method in which the first predetermined light and the second predetermined light are radiated toward the outside of the light source unit and utilized.

5. the predetermined optical member has a function of a lens having a minute step or a minute discontinuous portion of a curved surface on a light incident surface or a light exit surface, 5. The method for utilizing predetermined light according to claim 4, wherein the first predetermined light and the second predetermined light are irradiated onto an object (20), and the first predetermined light and the second predetermined light obtained from the object are utilized.

6. 6. The method for utilizing predetermined light according to claim 5, further comprising the steps of separating the first predetermined light and the second predetermined light obtained from the object, and detecting the first predetermined light and the second predetermined light separately.

7. The first predetermined light and the second predetermined light are condensed at a predetermined position; 7. The method for utilizing predetermined light according to claim 6, wherein the separated first predetermined light and second predetermined light are collected at a detection location different from the predetermined position.

8. The predetermined optical member has minute steps or minute discontinuities in the surface, a first emitted light source is caused to travel in a divergent state toward the predetermined optical member; a second emitted light from a second light source is also propagated in a divergent state toward the predetermined optical member; causing first light and second light included in the first radiation light to travel through different optical paths; the predetermined optical member acts so that a first optical path difference between the first light and the second light exceeds a coherence length; generating a first predetermined light by adding the intensities of the first light and the second light after passing through the predetermined optical member at a predetermined location; causing third light and fourth light included in the second radiation light to travel through different optical paths; the predetermined optical member acts so that a second optical path difference between the third light and the fourth light exceeds the coherence length; generating a second predetermined light by adding the intensities of the third light and the fourth light after passing through the predetermined optical member at the predetermined location; A service providing method for irradiating an object (20) with the first predetermined light and the second predetermined light, and providing a service to a user by utilizing the first predetermined light and the second predetermined light obtained from the object.

9. The service providing method according to claim 8, wherein a service is provided that performs processing or operations that should be performed by the user.

10. 9. The service providing method according to claim 8, wherein a service is provided that provides feedback to learning of the artificial intelligence.

11. The service providing method according to claim 8, further comprising providing a service for the user to operate a robot installed at a remote location.

12. including a measurement or input device, an external system or a service providing domain; forming a virtual image in a virtual space in the service providing domain; The virtual image in the virtual space has a three-dimensional structure and its position and shape change over time. the measuring device and the input device include a light source unit and a measurement unit, the light source unit includes a light emitting unit and a predetermined optical member; the light-emitting unit has a first light-emitting source and a second light-emitting source, the first emitted light from the first light source travels toward the predetermined optical member in a divergent state; the second emitted light from the second light source also travels toward the predetermined optical member in a divergent state; the predetermined optical member through which the first radiation light and the second radiation light pass has minute steps or minute discontinuities in its surface; a first light included in the first emitted light travels through a first optical path related to the predetermined optical member; a second light included in the first emitted light travels along a second optical path related to the predetermined optical member; the light source unit disposes the predetermined optical member so that a first optical path difference between the first optical path and the second optical path exceeds a coherence length; generating a first predetermined light by adding the intensities of the first light and the second light having the first optical path length difference at a predetermined location; a third light included in the second emitted light travels through a third optical path related to the predetermined optical member; a fourth light beam included in the second emitted light beam travels through a fourth optical path related to the predetermined optical member; the light source unit disposes the predetermined optical member so that a second optical path length difference between the third optical path and the fourth optical path also exceeds the coherence length; generating a second predetermined light by adding the intensities of the third light and the fourth light having the second optical path length difference at the predetermined location; the first predetermined light and the second predetermined light are irradiated onto the object 20, and the first predetermined light and the second predetermined light obtained from the object are detected by the measurement unit; A service providing system in which the service providing domain changes the virtual image and provides a service based on the result of the detection.

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