Prescribed light generation method, prescribed light using method, service provision method using prescribed light, measurement / imaging method, optical characteristic conversion element, light source part, measurement part, measurement device, prescribed light use device and service provision system

Abstract

To provide a method for generating prescribed light having a characteristic desirable or relatively appropriate in various application fields and service provision fields using light or to allow an application method and a service method using the prescribed light to be provided without being limited to the prescribed light generation method.SOLUTION: First light having a first optical characteristic is formed in a first optical path, second light having a second optical characteristic is formed in a second optical path, and the first light and the second light are synthesized to form prescribed light. Here, at least a portion of the first optical path and the second optical path is different, and the first optical characteristic is different from the second optical characteristic. Further, the prescribed light may be applied to imaging and measurement / measuring as a method / device for using the prescribed light, and may be applied to service provision / system construction using information obtained there. Otherwise, the prescribed light is irradiated to a measurement object, first information is acquired from the prescribed light and detection light acquired from the measurement object, and second information may be acquired from the detection light by using the first information.SELECTED DRAWING: Figure 28D

Description

Technical Field

[0001] This embodiment relates to the technical field of controlling the characteristics of light itself, application fields using light, or service provision fields utilizing light.

Background Art

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

[0003] Also, as application fields using light, imaging techniques that arrange an imaging element at the imaging position of an object and application fields utilizing spectroscopic characteristic measurement techniques for the object to be measured are known. Furthermore, application fields such as imaging spectroscopy that combines the above imaging techniques and spectroscopic characteristic measurement techniques have recently been developed. Also, not limited to these, there are application fields that utilize the measurement results of the reflection amount, transmission amount, absorption amount, and scattering amount of light or their temporal changes.

[0004] Furthermore, as a service provision field utilizing light, a technical field that provides services to users by leveraging the information obtained in the above application fields using light is known. Also, not limited to this, service provision methods that utilize light as means for providing services to users, such as visualization display and laser processing, are known.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To provide a method for generating a predetermined light having desirable or relatively appropriate characteristics in various application fields and service providing fields using light. Alternatively, without being limited thereto, an application method or a service method using the predetermined light may be provided.

[0007] Furthermore, to provide an optical property conversion element used for generating light having desirable or relatively appropriate characteristics in various application fields using light, or a light source unit, a measurement unit, a measuring device, a predetermined light utilization device, or a service providing system may be provided.

[0008] Also, an imaging method, a spectroscopic measurement, an optical measurement / measurement method using the predetermined light may be provided, or a measuring device using these methods may be provided.

Means for Solving the Problems

[0009] Form a first light having a first optical property in a first optical path, form a second light having a second optical property in a second optical path, and combine the first light and the second light to form a predetermined light. Here, at least a part of the first optical path and the second optical path is different, and the first optical property and the second optical property are different.

[0010] Alternatively, it is composed of a first region and a second region that are different from each other. After passing through the first region, the optical properties of the first light having the first optical property and the second light having the second optical property after passing through the second region are different from each other. The predetermined light is formed by an optical property conversion element having a spatial structure in which the first light and the second light are combined to enable the generation of the predetermined light. And a light source unit, a measurement unit, a measuring device, and a predetermined light utilization device using the optical property conversion element may be configured.

[0011] Furthermore, as the method / device for using the predetermined light, it may be applied to imaging, measurement / measurement, or a service provision / system construction using the information obtained therefrom may be performed.

[0012] Alternatively, irradiate the measurement object with the predetermined light, acquire first information from the predetermined light or the detection light obtained from the measurement object, and further acquire second information from the detection light using the first information.

Brief Description of Drawings

[0013]

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Embodiments for Carrying Out the Invention

[0014] Chapter 1 System Overview Used in the Present Embodiment Figure 1 shows the system used in the present embodiment. The light emitted from the light source unit 2 is irradiated onto the object 20 via the light propagation path 6. Then, the light obtained from this object 20 is incident on the measurement unit 8 via the light propagation path 6 again. Moreover, not limited thereto, the light emitted from the light source unit 2 may be directly incident on the measurement unit 8 via the light propagation path 6. As another embodiment, the light emitted from the light source unit 2 may reach the display unit 18 via the light propagation path 6, and predetermined information may be displayed on this display unit 18.

[0015] The measuring device 12 in the present embodiment is composed of a light source unit 2, a measurement unit 8, and a system internal control unit 50. Further, outside this measuring device 12, there is an application field (various optical application fields) adaptation unit 60. And each part 62 - 76 within this application field (various optical application fields) adaptation unit 60 can individually exchange information with the system internal control unit 50.

[0016] For example, the information obtained from the measurement result in the measurement unit 4 and each part 62 - 76 within the application field (various optical application fields) adaptation unit 60 are used in cooperation to provide services to the user.

[0017] The service providing system 14 in this embodiment is composed of the above measurement device 12, the adaptation unit 60 for the above application field (various optical application fields), and the external system 16, and is structured to be able to provide all services to users. Here, the remaining part of the service providing system 14 excluding the external system 16 functions independently as the optical utilization device 10.

[0018] The optical application field 100 applied as this embodiment extends over a wide range as shown in FIG. 2. However, it is not limited thereto, and all application fields 100 related to light in some form (including displays using light) are the targets of this embodiment.

[0019] FIG. 2 shows a list of the (desirable) optical characteristic contents 102 required for each optical application field 100. In particular, in this embodiment, it can conform to the required (desirable) optical characteristic contents 102 enclosed within the square frame.

[0020] Chapter 2: Outline of the Basic Optical Actions Used in this Embodiment FIG. 3 shows the basic principle of the optical action in this embodiment. That is, a first light 202 having a first optical characteristic is formed in the first optical path 222, and a second light 204 having a second optical characteristic is formed in the second optical path 224. Then, the first light 202 and the second light 204 are combined within the light synthesis location 220 to form a predetermined light 230. Here, at least a part between the first optical path 222 and the second optical path 224 is arranged in different spatial locations. Furthermore, the first optical characteristic of the first light 202 and the second optical characteristic of the second light 204 are different from each other. And not limited thereto, a third light 206 having a third optical characteristic may be formed in the third optical path 226. In this case, at least a part of this third optical path 226 may be arranged in a spatial location different from the first optical path 222 and the second optical path 224.

[0021] 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 in different spatial locations, wave front division may be performed on the initial light 200 to individually extract each of the lights 202 to 206. That is, the regions 212 to 216 are arranged at different locations on the light cross-section of the incident initial light 200 (the plane obtained by cutting the light beam constituted by the initial light 200 with a plane perpendicular to the traveling direction of the initial light 200) or on the wave front of the initial light 200, and each of the lights 202 to 206 is individually extracted.

[0022] The above technical content will be re-explained from the perspective of the structure of the optical property conversion element 210 that realizes the optical action. That is, the optical property conversion element 210 used in the present embodiment includes a first region 212 and a second region 214 that are different from each other. And the operation / control parameters 280 indicating the characteristics of each of the regions 212 and 214 are different from each other. Therefore, the first light 202 after passing through the first region 212 and the second light 204 after passing through the second region 214 have different optical characteristics from each other. Further, at the photosynthesis location 220, the optical property conversion element 210 has a spatial structure in which it is easy to synthesize the first light 202 and the second light 204 to form a predetermined light 230.

[0023] As a specific example of the spatial structure in which it is easy to synthesize the first light 202 and the second light 204 to form a predetermined light 230, it may have a structure in which the incident initial light 200 is wave-front divided into each of the lights 202 and 204. That is, a spatial structure in which the first region 212 is arranged in a predetermined region within the light beam cross-section obtained by cutting the light beam with a plane perpendicular to the traveling direction of the incident initial light 200 may be adopted. And in other regions within the above light beam cross-section, a spatial structure in which the second region 214 is arranged is adopted. However, not limited thereto, as another method, amplitude division or intensity division may be performed on the initial light 200.

[0024] As another application example, a third region 216 may be further provided in the optical property conversion element 210 so that the third light 206 passing through the third region 216 can be extracted.

[0025] Within the optical operation location 240 of FIG. 3, the object 20 of FIG. 1, the display unit 18, the measurement unit 8, and the application field (various optical application fields) adaptation unit 60 are included.

[0026] FIG. 4 describes, in a list form, the optical characteristics 252 that are the operation / control targets of the optical characteristic conversion element 210 described in FIG. 3 and the placement location 258 of the optical characteristic conversion element 210 in the present embodiment.

[0027] Among the operation / control items 250 in FIG. 4, first, the optical characteristics 252 that are the operation / control targets of the optical characteristic conversion element 210 will be described. Explaining along the classification content 260 of the optical characteristics 252 that are the operation / control targets, the optical characteristics 252 that are the operation / control targets of the optical characteristic conversion element 210 can be classified into 'the light quantity distribution within the light beam cross-section of the initial light 200', 'the phase characteristics or wavefront characteristics within the light beam cross-section of the initial light 200', and 'the phase synchronization characteristics between the light elements (wave elements) included in the operation / control light beam'. Specific examples 270 of the optical characteristic conversion element 210 corresponding to each classification 260 and the operation / control parameters 280 for each specific example will be described below.

[0028] In the optical characteristic conversion element 210 described in the present embodiment, the incident initial light 200 is wavefront-divided or amplitude-divided / light quantity-divided, and the parameter 280 values for operation / control are changed for each divided light to operate or control the optical characteristics.

[0029] When using a slit or pinhole whose transmittance or reflectance changes discretely as a specific optical characteristic conversion element 210 for operating / controlling the light quantity distribution within the light beam cross-section of the initial light 200, the period (pitch), slit width, and pinhole size are changed to perform the operation / control of the optical characteristics.

[0030] Also, as a specific example 270, when using a transmissive or reflective gradation providing optical component, the gradation characteristics of the transmittance or reflectance are manipulated / controlled. Moreover, not limited thereto, the light intensity distribution of the light entering the waveguide may be manipulated / controlled to manipulate / controlled the mode of the light propagating in the waveguide (this specific example will be described later with reference to FIG. 5B).

[0031] When manipulating / controlling the light quantity distribution within the light beam cross-section of the initial light 200 by other methods, the transmittance or the light quantity distribution control value after reflection may be manipulated / controlled.

[0032] When using a diffuser as the specific optical property conversion element 210 for manipulating / controlling the phase characteristics or wavefront characteristics within the initial light 200, not limited to the average roughness “Ra” of its surface and the average pitch “Pa” of the surface uneven shape, the in-plane period for each predetermined Fourier component obtained when performing a Fourier transform on the surface uneven shape, the ratio of the vertical amplitude to the period, etc. may be manipulated / controlled.

[0033] Also, when using a diffraction grating or a hologram, the period, the width ratio between the top surface and the bottom surface, etc. may be manipulated / controlled. Also, in a diffraction grating or a hologram, it is often composed of two mutually parallel planes (in a blazed grating, one plane has an inclination) that respectively constitute the top surface and the bottom surface. However, not limited thereto, the number of planar steps may be changed. Increasing the number of planar steps in this way tends to improve the reduction effect of at least one of optical noise and coherence, as implied by the results of the theoretical analysis performed in Chapter 3.

[0034] When using various wave aberration generating components, the optical design of the condenser lens may be changed, or the bending direction of the condenser lens may be changed. Also, it is known that spherical aberration occurs when a parallel plate with a large thickness is placed in the light converging optical path, and coma aberration occurs when an inclined plate or a non-parallel plate is placed. Therefore, the optical characteristics can be manipulated / controlled by changing the thickness of the parallel plate, the tilt angle, or the angle between the planes in the non-parallel plate.

[0035] When a stepped plate having a step “t” in the light beam cross-section of the initial light 200 is placed in the optical path, an optical path length difference of “(n - 1)t” occurs. Here, “n” represents the refractive index of the stepped plate. And a phase difference corresponding to this optical path length difference occurs. In this case, the optical characteristics can be manipulated / controlled by changing the step on the surface of the stepped plate (the thickness step of the flat plate).

[0036] Moreover, not limited thereto, the phase characteristics (wavefront characteristics) can be manipulated / controlled even if the wavefront characteristics after transmission or reflection are changed by some method.

[0037] As will be described in detail in Chapter 3 with reference to FIG. 8, the optical path length changer can be used as the optical characteristic conversion element 210 to manipulate / control the phase synchronization characteristics. In this case, it is desirable that the optical path length generated in the optical path length changer is larger than the coherence length described by Equation 1 below. As the placement location 258 of the optical characteristic conversion element 210 described above in this embodiment, it may be placed on the light converging plane or the image pattern forming plane, the aperture plane, or the near field 170 in the vicinity thereof. Moreover, not limited thereto, as another embodiment, it may be placed in the far field 180 located far from the light converging plane or the image pattern forming plane.

[0038] In this embodiment, a Fraunhofer diffraction area that is far from the above-mentioned light collecting surface or imaging surface and aperture surface is referred to as a far region 180. On the other hand, a region closer than the Fresnel diffraction area located closer thereto is referred to as a vicinity region.

[0039] For more specific description, the diameter of the light beam cross-section of the initial light 200 or the length of one side of the square aperture is denoted as "D", and the light beam propagation direction of the initial light 200 is taken as the "z-axis". Also, a specific wavelength included in the initial light 200 is represented by "λ0".

[0040] In this case, in diffraction theory, the range of "-D 2 / λ0 ≦ z ≦ +D 2 / λ0" is said to be the Fresnel diffraction area. Therefore, in this embodiment as well, the above range is defined as the vicinity region 170. On the other hand, the range of "|z| > +D 2 / λ0" is known as the Fraunhofer diffraction area. Therefore, in this embodiment as well, the above range is defined as the far region 180.

[0041] By the way, when the initial light 200 is divergent light having a divergence angle "θ", when it is far from the light collecting surface or imaging surface and aperture surface, the light beam cross-section size increases and measurement at the measurement unit 8 becomes impossible. In this embodiment, it is premised on the measurability at the measurement unit 8. Therefore, in this embodiment, the upper limit value of the far region 180 is also defined.

[0042] When the value of the light beam cross-section size "D" on the light collecting surface or imaging surface and aperture surface is relatively small, the light beam cross-section size with respect to the distance "z" from the light collecting surface or imaging surface and aperture surface is approximated by "2zNA". By the way, in a vacuum, it is defined as "NA ≡ 2sinθ". Therefore, the detected light amount at a position "z" away is "D 2 / 4NA 2 z 2” decreases. Therefore, in this embodiment, considering the upper limit value of the distance “z” corresponding to the far region 180, “ D 2 / λ0 < |z| < 1×10 8 D 2 / 4NA 2 ” is defined within the range of the far region 180. Further, considering ensuring the measurement accuracy at the measurement unit 8, the range of the far region 180 is “ D 2 / λ0 < |z| < 1×10 4 D 2 / 4NA 2 ” is desirable.

[0043] According to the diffraction theory of optics, when the above-mentioned condensing surface or imaging surface / aperture surface position coincides with the focal plane of the condenser lens, it is known that the vicinity of the pupil plane of this condenser lens or the vicinity of the aperture surface of the condenser lens corresponds to the far field 180 with respect to the above-mentioned condensing surface or imaging surface. Therefore, in this embodiment, not limited to the above numerical range, the positions near the pupil plane of the condenser lens or near the aperture surface of the condenser lens are also included in the “far region 180”.

[0044] The outline of this embodiment was described with reference to FIG. 4. Next, specific embodiments will be described with reference to FIGS. 5A to 7C. And in order to clarify the correspondence between the contents of each of FIGS. 5A to 7C and the classification content 260 shown in FIG. 4 and the arrangement location 258 of the optical property conversion element 210, symbols 290 are set for each specific example 270 in FIG. 4 and the arrangement location 258 of the optical property conversion element 210.

[0045] FIG. 5A shows a specific embodiment example corresponding to the embodiment “N01” in the list of FIG. 4. That is, in FIG. 5A, a slit arranged on or near the condensing surface, imaging surface / aperture surface or in the vicinity thereof 170 is used as the optical property conversion element 210, and the light quantity distribution here is operated / controlled.

[0046] The light transmission region within this slit corresponds to the first region 212. And the light shielding region within the slit corresponds to the second region 214. In Fig. 5A, for the selective extraction of the first lights 202-1 to -3 among the initial lights 200 that head towards the photosynthesis location 220, the light transmission (first region) within the slit is utilized. However, not limited thereto, selective extraction of the light heading towards the photosynthesis location 220 may be performed by utilizing the partial reflection of light.

[0047] The first lights 202-1 to -3 that have passed through each first region 212 become parallel lights after passing through the collimating lens 318. And the regions before and after passing through this collimating lens 318 are utilized as the photosynthesis location 220. Each of the first lights 202-1 to -3 synthesized at this photosynthesis location 220 forms a predetermined light 230.

[0048] As an example of the optical operation location 240 in Fig. 5A, it constitutes the imaging unit of a hyperspectral camera used in the field of imaging spectroscopy with a combination of a spectroscopic element (blazed grating) 320, a condenser lens 314, and an imaging element 300. And in order to expand this imaging field of view, the imaging lens 310 or the optical property conversion element 210 (slit) is in a form that can move in the X direction 322. Regarding the measurement technology using this imaging spectroscopy, it will be described in detail later with reference to Figs. 21A and 21B.

[0049] The embodiment of the optical operation location 240 when using a specific embodiment example corresponding to the embodiment "N01" is not limited to Fig. 5A, and an embodiment of the optical operation location 240 corresponding to any application set within the application field (various light application fields) adaptation part 60 in Fig. 1 can be adopted.

[0050] Fig. 5B shows a specific embodiment example corresponding to the embodiment "F02" in the list of Fig. 4. That is, in Fig. 5B, the optical property conversion element 210 is arranged in the far - away region 180, and the intensity distribution (light quantity distribution) of the light beam cross - section obtained by cutting with a plane perpendicular to the traveling direction of the initial light 200 is operated / controlled.

[0051] In the first region 212 within the optical property conversion element 210, there is no light shielding (it has a light transmittance of approximately "100%"), so the initial light 200 passing through the first region 212 travels straight. On the other hand, in the third region 216, since the light transmittance is set to approximately "0%", the initial light 200 reaching here is shielded. Furthermore, in the second region 214, the light transmittance changes depending on the passing location.

[0052] And the intensity distribution of the converging light 218 obtained after being converged by the condenser lens 314 can be changed from the intensity distribution of (a) to the intensity distribution of (b) by inserting the optical property conversion element 210 having the above characteristics.

[0053] When the converging light position 218 of this condenser lens 314 is made to coincide with the entrance surface of the optical fiber (waveguide) 330, it becomes possible to optimize the mode control of the light propagating in the optical fiber (waveguide) 330 by the operation / control of the light quantity distribution based on the above optical property conversion element 210.

[0054] As a specific example of the optical operation location 240 in FIG. 3, in FIG. 5B, it constitutes an example of an optical propagation path 6 (FIG. 1) combining the optical fiber (waveguide) 330 and the measurement unit 8. The embodiment of the optical operation location 240 when using the specific embodiment example corresponding to the embodiment "F02" is not limited to FIG. 5B, and an embodiment of the optical operation location 240 corresponding to any application set within the application field (various optical application fields) adaptation section 60 in FIG. 1 can be adopted.

[0055] Fig. 6A(a) shows a specific embodiment example corresponding to the embodiment "N11" in the list of Fig. 4. That is, in Fig. 6A(a), a diffuser plate is arranged as the optical property conversion element 210 at the position (on the condensing surface or the imaging surface) of the converging light 218 of the initial light 200 condensed by the condensing lens 314, and the phase property (wavefront property) with respect to the converging light 218 is manipulated / controlled. Then, the first / second lights 202, 204 that have passed through this diffuser plate enter the optical fiber (waveguide) 330. Therefore, in the specific embodiment shown in Fig. 6A(a), the inside of the optical fiber (waveguide) 330 serves as the photosynthesis location 220. Furthermore, this optical fiber (waveguide) 330 also serves as the optical propagation path 6 that guides the predetermined light 230 to an arbitrary location.

[0056] As a specific example of the optical operation location 240 in Fig. 3, in Fig. 6A(a), it serves as the collection information storage 74 by combining the movable imaging lens 312 and the optical recording / playback medium 26. However, it is not limited to this, and an embodiment of the optical operation location

[0057] Here, the operation / control parameter 280 for the diffuser plate manipulates / controls the property between the first region 212 and the second region 214 with various set values described in the list of Fig. 4. For example, when changing the average roughness "Ra1" in the first region 212 and the average roughness "Ra2" in the second region 214, it is necessary to satisfy the condition of "Ra2 / Ra1 > 1" to exhibit the effect described in Chapter 3 later. According to the actual experimental results, when further satisfying the condition of "Ra2 / Ra1 ≧ 1.5", the effect is improved. And it is desirable to satisfy the condition of "Ra2 / Ra1 ≧ 3".

[0058] Figure 6A(b) shows the characteristics of the maximum incident angle "θ" of light that can propagate within the core region 332 of the optical fiber (waveguide) 330. When the maximum incident angle of light that can propagate within the core region 332 is expressed as "θ", the value of "NA = sinθ" is determined for each optical fiber (waveguide) 330. Therefore, it is necessary to set the incident angle of light entering the optical fiber (waveguide) 330 so that it is below the "NA value" defined for each optical fiber (waveguide) 330.

[0059] Therefore, when arranging the optical property conversion element 210 that operates / controls the phase property (wavefront property) near the incident surface of the optical fiber (waveguide) 330, it is necessary to consider the above-mentioned incident angle range for the optical fiber (waveguide) 330.

[0060] When using a diffuser plate as the optical property conversion element 210 that operates / controls the phase property (wavefront property), as a condition that its surface roughness average period "Pa" satisfies, it is necessary to satisfy "Pa ≧ λ / NA". Here, "λ" represents the wavelength of the light propagating within the optical fiber (waveguide) 330. Similarly, when using a diffraction grating or a hologram, it is also necessary to satisfy "Pa ≧ λ / NA" with respect to the pitch "Pa" of the diffraction grating or the hologram. Furthermore, when the condition of "Pa ≧ λ / (4NA)" is satisfied, the performance becomes more stable.

[0061] When changing the surface roughness average periods "Pa1" and "Pa2" between the first region 212 and the second region 214 in order to exhibit the effects described later in Chapter 3 in Figure 6A(a), it is necessary to satisfy the condition of "Pa2 / Pa1". Also, for the above reasons, it is necessary to set "Pa1 ≧ λ / NA" and "Pa2 ≧ λ / NA". Furthermore, when the conditions of "Pa1 ≧ λ / (4NA)" and "Pa2 ≧ λ / (4NA)" can be satisfied, the performance becomes even more stable.

[0062] In the optical property conversion element 210 (diffusion plate) shown in the embodiment example of FIG. 6A(a), it is divided into two regions, a first region 212 and a second region 214. However, it is not limited thereto, and the inside of the optical property conversion element 210 (diffusion plate) may be divided into three or more regions or four or more regions.

[0063] Also, in the optical property conversion element 210 shown in the embodiment example of FIG. 6A(a), the first region 212 and the second region 214 are formed of diffusion plates with different operation / control parameters 280. However, it is not necessarily required that the first region 212 and the second region 214 be formed of the same diffusion plate. That is, within the same optical property conversion element 210, combinations may be made between other specific examples 270 for operating / controlling the phase characteristics (wavefront characteristics). For example, the first region 212 within the same optical property conversion element 210 may be formed of a diffusion plate, and the second region 214 may be formed of a diffraction grating / hologram.

[0064] FIG. 6B shows a specific embodiment example corresponding to the embodiment “N12” in the list of FIG. 4. That is, in FIG. 6B, a diffraction grating or a hologram is arranged as the optical property conversion element 210 at the position (on the condensing surface or the imaging surface) of the converging light 218 of the initial light 200 condensed by the condensing lens 314, and the phase characteristics (wavefront characteristics) with respect to the converging light 218 are operated / controlled.

[0065] Between the first region 212 and the second region 214 in the optical property conversion element 210 of FIG. 6B, the number of planar steps, the pitch (period) of the steps, and the planar width ratio (Duty) between the upper surface and the bottom surface are changed. When a diffraction grating or a hologram is used as the optical property conversion element 210, the diffraction angle may exceed the “NA value” of the optical fiber (waveguide) 330 described above. As a countermeasure, in FIG. 6B, an optical guide (waveguide) 340 with a large “NA value” is used.

[0066] In FIG. 6B, as a specific example of the optical operation location 240 in FIG. 3, an illumination system is configured to irradiate a predetermined light 230 emitted from an optical guide (waveguide) 340 onto an object 28 to be irradiated with light. However, it is not limited thereto, and an embodiment of the optical operation location 240 corresponding to any application set in the application field (various optical application fields) adaptation section 60 in FIG. 1 can be adopted.

[0067] As shown in FIG. 6A(b) and FIG. 6B, when a diffusion plate or a diffraction grating / hologram is used as a specific example 270 of the optical property conversion element 210 that performs operation / control of phase characteristics (wavefront characteristics), diffracted light corresponding to the periodicity (for example, the average period “Pa” of the surface roughness) along the surface direction of the optical property conversion element 210 is generated. In this embodiment, the generation of the diffracted light is utilized to perform operation / control of the phase characteristics (wavefront characteristics) with respect to the initial light 200.

[0068] FIG. 6C illustrates an example of a method for generating a phase difference by utilizing the difference in the optical path within the optical guide 340 used as the photosynthesis location 220 or within the core region 332 of the optical fiber 330. The zero-order diffracted lights 232 and 234 with respect to the surface of the optical property conversion element 210 travel straight along the traveling direction of the initial light 200. On the other hand, the first-order diffracted lights 236 and 238 generated by the periodic uneven shape on the surface of the optical property conversion element 210 travel in the directions of angles “θ1” and “θ2” within the optical guide 340 or within the core region 332 of the optical fiber 330.

[0069] Incidentally, the traveling angles “θ1” and “θ2” of the first-order diffracted lights 236 and 238 change according to the period or average period “Pa1” in the first region 212 and the period / average period “Pa2” in the second region 214 in the optical property conversion element 210. Therefore, as shown in FIG. 6C, when the periods or average periods “Pa1” and “Pa2” are changed between the first region 212 and the second region 214, the optical path lengths of the first-order diffracted lights 236 and 238 when passing through the optical guide 340 or the core region 332 of the optical fiber 330 change. Therefore, in this embodiment, the value of “Pa2 / Pa1” needs to exceed “1” (1 < Pa2 / Pa1), and it is desirable to have a relationship of “1.2 ≦ Pa2 / Pa1”.

[0070] As described with reference to FIG. 6A(b), there is a relationship of "Pa1 = λ / nsinθ1" and "Pa2 = λ / nsinθ2" between the propagation angles "θ1", "θ2" of the first-order diffracted lights 236, 238 and "Pa1", "Pa2". Here, "n" represents the refractive index in the optical waveguide 340 or in the core region 332 of the optical fiber 330. Therefore, if "Pa2" is too large, "θ2≒ 0", and there is no optical path length difference between the zero-order diffracted light 234 and the first-order diffracted light 238.

[0071] On the other hand, as a condition for the first-order diffracted light 236 to stay within the core region 332 of the optical fiber 330, it is necessary to ensure "Pa1 ≧ λ / NA" (preferably "Pa1 ≧ λ / (4NA)"). (From the above condition of "1 < Pa2 / Pa1", it is necessarily required to satisfy the conditions of "Pa2 ≧ λ / NA" and "Pa2 ≧ λ / (4NA)".) For the above reasons, it is necessary to set an upper limit for the value of "Pa2 / Pa1".

[0072] Summarizing the above, in this embodiment, as a condition for the value of "Pa2 / Pa1", "1 < Pa2 / Pa1 < 10000" (preferably "1.2 ≦ Pa2 / Pa1 ≦ 1000") is set.

[0073] FIG. 6D shows a specific embodiment example corresponding to the embodiment "F13" in the list of FIG. 4. It has already been explained that spherical aberration occurs when a thick parallel plate is arranged in the light collection path using the condenser lens 314, and coma aberration occurs when an inclined plate is arranged. Therefore, in the specific example shown in FIG. 6D, the optical property conversion element 210 is arranged in the far region 180 to generate various aberrations. That is, a spherical aberration generating element 352 using a parallel plate is arranged as the first region 212 in the optical property conversion element 210. And a coma aberration generating element 354 using an inclined plate is arranged in the second region 214. In FIG. 6D, the spherical aberration generating element 352 using a parallel plate and the coma aberration generating element 354 using an inclined plate are integrally formed. However, it is not limited thereto, and the spherical aberration generating element 352 and the coma aberration generating element 354 using an inclined plate may be separated.

[0074] When aberration is generated by this method, if the amount of aberration is small, the effect of operating / controlling the phase characteristics (wavefront characteristics) cannot be obtained. On the contrary, if the amount of aberration is too large, the light cannot be focused, so the light does not enter the optical fiber (waveguide) 330. Therefore, in this embodiment, the range of the root mean square (RMS) value of the wavefront aberration to be generated is set to be 0.5λ or more and 100λ or less (desirably 0.3λ or more and 1000λ or less).

[0075] As a specific example of the optical operation location 240 in FIG. 3, in FIG. 6D, a rotatable mirror 316 is disposed in the optical path where the predetermined light 230 is focused on the screen 326 by the imaging lens 312, enabling the operation 324 of the focused spot on the screen 326. In this way, the function of the display unit 18 (FIG. 1) is achieved. However, it is not limited thereto, and an embodiment of the optical operation location 240 corresponding to an arbitrary application set in the application field (various optical application fields) adaptation unit 60 in FIG. 1 can be adopted.

[0076] FIG. 7A shows a specific embodiment example corresponding to the embodiment "F21" in the list in FIG. 4. That is, an optical path length conversion element is disposed in the far region 180 of the initial light 200 (for example, in the path of a parallel light beam), and the operation / control of the phase synchronization characteristics is performed as the optical characteristic conversion element 210. The optical characteristic conversion element 210 (optical path length conversion element) is formed of a transparent medium having a refractive index "n".

[0077] In the first region 2I2 and the second region 214 in the optical characteristic conversion element 210, there is a difference in thickness "t" with respect to the traveling direction of the initial light 200. As a result, an optical path length difference of "t(n - 1)" is generated between the first region 212 and the second region 214. The thickness "t" is adjusted so that this value is equal to or greater than the coherence length "ΔL0" described later in Equation 1. Further, if it is set as "t(n - 1) ≧ 2ΔL0" as the above numerical setting, the effect is further enhanced.

[0078] In FIG. 7A, the optical path through which the first light 202 passing through the first region 212 reaches the condenser lens 314 corresponds to the first optical path 222. Similarly, the optical path through which the second light 204 passing through the second region 214 reaches the condenser lens 314 corresponds to the second optical path 224. Then, the condenser lens 314 condenses the first light 202 and the second light 204 together toward the entrance surface of the optical fiber (waveguide) 330.

[0079] By passing through the optical fiber (waveguide) 330 together with the first light 202 and the second light 204, the two are synthesized to form a predetermined light 230. Therefore, the inside of this optical fiber (waveguide) 330 acts as a light synthesis location 220.

[0080] FIG. 7A shows an example using the optical fiber (waveguide) 330 as the light synthesis location 220. However, it is not limited thereto, and an optical guide (waveguide) 340 may be used as the light synthesis location 220. Further, as described in FIG. 5A for the light synthesis location 220, a region where the first optical path 222 and the second optical path 224 spatially overlap may be utilized.

[0081] The entrance surface and the exit surface of the optical fiber (waveguide) 330 or the optical guide (waveguide) 340 generally have an optical planar shape. In this embodiment, instead of the optical planar shape, a fine concavo-convex shape (light diffusing surface structure or diffraction grating structure) may be provided on the entrance surface or the exit surface of the optical fiber (waveguide) 330 or the optical guide (waveguide) 340. Then, the entrance surface or the exit surface of the optical fiber (waveguide) 330 or the optical guide (waveguide) 340 has the function of the diffusion plate or the diffraction grating / hologram described as the specific example 270 in FIG. 4. Thereby, without adding a new optical property conversion element 210, the entrance surface or the exit surface of the optical fiber (waveguide) 330 or the optical guide (waveguide) 340 can also function to operate / control the phase characteristics (wavefront characteristics). In this case, since both the phase synchronization characteristics and the phase characteristics (wavefront characteristics) with respect to the initial light 200 can be operated / controlled simultaneously, the optical noise reduction effect and the coherence reduction effect are further improved. Furthermore, simplification of the internal structure and cost reduction of the light source unit 2 can also be realized.

[0082] When a fine concavo-convex shape is provided on the entrance surface or the exit surface of the optical fiber (waveguide) 330 or the optical guide (waveguide) 340, an effective concavo-convex shape will be described below. First, the case of forming a fine concavo-convex shape with the structure of a diffraction grating or a hologram will be described. Let the mechanical step amount between the upper surface and the bottom surface in the structure of the diffraction grating or the hologram be represented by "t", and the refractive index in the optical guide (waveguide) 340 or in the core region 332 of the optical fiber (waveguide) 330 be represented by "n". Then, due to the above mechanical step, an optical path length difference of "t(n - 1)" occurs. And in this embodiment, the effect appears when this optical path length difference is "λ / 16" or more. Here, when the value of the wavelength "λ" is "400 nm" and "n ≒ 1.5", "t ≧ λ / 16(n - 1) ≒ 50 nm" is obtained. Therefore, when the amplitude value of the fine concavo-convex shape has a value of "50 nm" or more, the effects described in Chapter 3 will occur.

[0083] On the other hand, if the amplitude value of the fine concavo-convex shape is too large, the stability of operation / control will be impaired. Specifically, when the optical path length difference becomes "10000λ ≒ 4 mm" or more, the stability of operation / control will be impaired. Also, since the optical path length difference is given by "t(n - 1)", the maximum allowable mechanical amplitude value of the fine concavo-convex shape is desirably "8 mm" or less.

[0084] When the fine concavo-convex shape is constituted by the concavo-convex shape on the diffusion plate surface, it is expressed by the average roughness value "Ra" instead of the maximum amplitude value. Considering the above consideration results, if the range of the "Ra value" of the fine concavo-convex shape formed on the entrance surface or the exit surface of the optical fiber (waveguide) 330 or the optical guide (waveguide) 340 can be "50 nm ≦ Ra ≦ 8 mm" (desirably "13 nm ≦ Ra ≦ 2 mm"), the effects described in Chapter 3 can be exerted.

[0085] As a specific example of the optical operation location 240 in FIG. 3, FIG. 7A describes an example of an optical system that performs hologram recording on the measurement object 22 using the optical recording / playback medium 26. That is, the predetermined light 230 emitted from the optical fiber (waveguide) 330 is converted into parallel light by the collimating lens 318, and the reference light reflected by the mirror 376 and the reflected light from the measurement object 22 are combined by the half mirror 370. Then, the obtained combined light is irradiated onto the optical recording / playback medium 26 to perform hologram recording. However, not limited thereto, an embodiment of the optical operation location 240 corresponding to an arbitrary application set in the application field (various optical application fields) adaptation section 60 in FIG. 1 can be adopted.

[0086] FIG. 7B shows an example of an embodiment regarding the structure of the optical path length conversion element (optical property conversion element 210 that operates / controls the phase synchronization characteristics). FIG. 7B(a) shows a view seen from the direction along the traveling direction 348 of the initial light 200. FIG. 7B(b) shows a view seen from the direction opposite to the traveling direction orts of the initial light 200.

[0087] FIG. 7B(c) shows a view seen from the cross-sectional direction perpendicular to the traveling direction 348 of the initial light 200. As shown in FIG. 7B(c), the initial light 200 is structured to be wavefront-divided into 48 regions (12 regions × 4 regions). That is, a splitting method that divides the light beam cross-section of the initial light 200 into 12 parts in the angular direction and 4 parts in the radial direction is combined.

[0088] As the 12-division method in the angular direction, 11 semi-circular transparent plates with a thickness of "1 mm" are adhered while being sequentially rotated by "30 degrees" each. And the 4-division in the radial direction is adhered while aligning the centers of cylinders with different radii and a thickness of "12 mm". As a result, the total thickness amount for each region changes by "1 mm" each. In this embodiment, the change amount of the total thickness for each region is set to "1 mm". However, not limited thereto, the change amount of the total thickness for each region may be set to other values.

[0089] FIG. 7C shows an application example regarding the structure of the optical path length conversion element (optical property conversion element 210 that operates / controls the phase synchronization property). Similar to FIG. 7B, in FIG. 7C, the optical path length conversion element is formed of a transparent material, and the initial light 200 passes through it. And with respect to the light beam cross-section of the passing initial light 200, it has a structure divided into 12 parts in the angular direction. When viewed in the light traveling direction 348 of the initial light 200, the thickness changes from "1 mm" to "12 mm" in "1 mm increments".

[0090] In the structure of FIG. 7C, it is devised such that the number of interface surfaces arranged along the light traveling direction 348 of the passing initial light 200 becomes the minimum number of "two surfaces each". If the planar accuracy of the interface surface existing at the interface between the transparent medium region and the air region constituting the optical path length conversion element is low, the wavefront accuracy of the light after passing through there deteriorates. Therefore, when setting the number of interface surfaces to the minimum number, the deterioration of the wavefront accuracy of the light after passing through the optical path length conversion element can be reduced.

[0091] Furthermore, in the structure of FIG. 7C, the side surfaces 380 of the step between each region in the optical path length conversion element (that is, the side surfaces of the boundary line where the thickness changes in the optical path length conversion element) all have a structure that can be seen from a specific direction (a direction perpendicular to the B surface). By having this structure, the manufacturability of the optical path length conversion element is improved, and the cost reduction of the optical path length conversion element becomes possible.

[0092] FIG. 7C shows the structure of the optical path length conversion element (optical property conversion element 210 that operates / controls the phase synchronization property), but at the same time, it may also have a function of operating / controlling the phase property (wavefront property). That is, at least one of the interface surfaces arranged in the direction perpendicular to the light traveling direction 348 of the initial light 200 is provided with a fine uneven structure instead of an optically flat surface. As this fine uneven structure example 270, a diffusion plate structure or a diffraction grating / hologram structure may be provided. Thereby, this interface surface has a function of operating / controlling the phase property (wavefront property). As a result, both the phase synchronization property and the phase property (wavefront property) can be used in combination for operation / control with a single optical element, so the optical noise reduction effect and the coherence reduction effect are improved. Furthermore, the simplification and cost reduction of the entire optical system can be achieved.

[0093] It is more efficient to manipulate / control the phase synchronization characteristics by passing parallel light traveling in the same direction through the optical path length conversion element. On the other hand, the traveling direction of the light passing through the boundary surface with a fine uneven structure is likely to change according to the optical path (that is, when parallel light passes through the boundary surface with a fine uneven structure, it is likely to change into divergent light). Therefore, it is desirable to provide a fine uneven structure on the surface of the boundary surface located behind the light traveling direction 348 among the boundary surfaces existing on both sides in the optical path length conversion element.

[0094] Regarding the effective uneven structure dimension range in the case of providing a fine uneven structure on the boundary surface, the content described with reference to Fig. 7A can also be applied. That is, the effective uneven structure dimension range in this case can be defined as "50 nm or more and 8 mm or less" with respect to the maximum amplitude value of the step. On the other hand, when expressed by the average value "Ra" of the surface roughness, the effects described in Chapter 3 can be exhibited when "50 nm ≤ Ra ≤ 8 mm" (preferably "13 nm ≤ Ra ≤ 2 mm") can be achieved.

[0095] Chapter 3: Outline of the basic concept of this embodiment, description of the experimental results of verification, and theoretical analysis results When manipulating / controlling the phase synchronization characteristics among the optical characteristics 252 of the light to be manipulated / controlled, as shown in Fig. 4, an optical path length conversion element (Optical path length converter) is used as the optical characteristic conversion element 210. This generates an optical path length difference between the first optical path 222 (see Fig. 3) when the first light 202 passes through the first region 212 of the optical characteristic conversion element 210 and the second optical path 224 when the second light 204 passes through the second region 212. The light cross-section of the initial light 200 may be wave front division in the first region 212 and the second region 212 to be divided into the first light 202 and the second light 204. Also, not limited to this wave front division, for example, amplitude division or intensity division may be used to divide into the first light 202 and the second light 204.

[0096] Furthermore, without being limited thereto, an optical path length difference may be generated between a third optical path 226 when a third light 206 passes through a third region 216 of the optical property conversion element 210 and the first optical path 222 described above. And an optical path length difference may be generated between the third optical path 226 and the second optical path 224. As an application example thereof, without being limited to three regions, an optical path length difference may be generated for each of four or more regions. In the present embodiment, by technically devising the above optical path length difference to be larger than the coherence length described later by Equation 1, optical noise is significantly reduced. The basic concept of this technical device is as follows. That is, by synthesizing the first light 202 and the second light 204 at the photosynthesis location 220, an ensemble averaging effect between the optical noise generated in the first light 202 and the optical noise generated in the second light 204 is generated. Furthermore, when the third light 206 or more lights are also synthesized, the above averaging effect is further improved. FIG. 9 shows experimental results in which optical noise is reduced as the number of wavefront divisions (number of region divisions or number of optical path divisions) increases (details will be described later).

[0097] FIG. 8 is an explanatory diagram schematically showing this basic concept. Generally, laser light has a "single wavelength", and it is easy to consider that the envelope of the electric field amplitude is uniform everywhere along the propagation direction of the laser light. However, there are few laser lights with a wavelength width that is completely "0". For example, many commercially available laser light sources have a wavelength width "Δλ" of about "2 nm". When the center wavelength of this light source is "λ0", all types of light are in space during propagation

[0098]

Number

[0099] The initial light 200 that has entered in a form in which the initial wave trains 400 shown in Fig. 8(a) are continuously generated is wavefront-divided when passing through an optical property conversion element 210 that performs operation / control of the phase synchronization property. And Fig. 8(b) shows the spatial propagation state (wave train state 406) of the first light 202 that has passed through the first region 212 in the optical property conversion element 210 shown in Fig. 3. Since the first light 202 is extracted as a result of wavefront division of the initial light 200, the amplitude in Fig. 8(b) is smaller than the amplitude in Fig. 8(a).

[0100] Fig. 8(c) shows the spatial propagation state (wave train state 408) of the second light 204 that has passed through and been extracted from the second region 214. The amplitude in Fig. 8(c) is almost the same as that in Fig. 8(b), but there is an optical path length difference between the two. Therefore, in Figs. 8(b) and 8(c), a shift in the center position of the wave trains 406 and 408 occurs.

[0101] FIG. 8(d) shows a situation where both wave trains 406 and 408 are subjected to a synthesizing or combining process 410 at the photosynthesis location 220 to form a predetermined light 230. When the optical path length difference occurring between the two is greater than the coherence distance represented by Equation 1, the wave trains 406 and 408, which are in a phase-asynchronous 402 relationship with each other, are synthesized, resulting in an ensemble average effect of intensities 420. Along with this, an averaging effect occurs between the optical noises generated within the first light 202 and the optical noises generated within the second light 204.

[0102] Light with a wide wavelength range (wavelength width “Δλ”) included in a light beam propagating in space is called panchromatic light. On the other hand, light with a narrow wavelength range is called monochromatic light. Although there is a difference in the magnitude of the wavelength width “Δλ”, since any light has a specific wavelength width “Δλ”, a coherence distance “ΔL0” represented by Equation 1 can be defined. Therefore, for both panchromatic light and light of the same wavelength, the above-described averaging effect of optical noises can be obtained.

[0103] As a result of this averaging effect, among the optical characteristic contents 102 required (desired) for each light application field shown in FIG. 2, not only “improvement in detection accuracy (optical S / N ratio)” and “improvement in measurement accuracy (optical S / N ratio)” but also “improvement in durability against optical disturbances” can be achieved.

[0104] As described above, reducing optical noise becomes possible by operating / controlling the phase synchronization characteristics. However, not limited to this, in the present embodiment, as shown in FIG. 4, by using the operation / control of the light quantity distribution and phase characteristics (wavefront characteristics) in addition, the optical characteristics (FIG. 2) required (desired) for each light application field can be provided. Furthermore, in the present embodiment, this “operation / control of phase synchronization characteristics” and “operation / control of phase characteristics (wavefront characteristics)” may be combined.

[0105] According to FIG. 4, a diffuser is cited as one of the specific examples 270 of the optical property conversion element capable of realizing the operation / control of the phase characteristics (wavefront characteristics). FIG. 9 shows the experimental results regarding the effect of reducing optical noise when using the diffuser 488. In the experiment to obtain FIG. 9, a diffuser having a value of 2.08 μm as the average roughness “Ra” was placed in the optical path to artificially generate optical noise. The spectroscopic characteristics were measured with a spectroscope placed inside the measurement unit 8, and the relative standard deviation value (the value normalized by the average value of spectroscopic detection) of the amount of optical noise generated within the range of the measurement wavelength from 1.45 μm to 1.65 μm was calculated. The vertical axis in FIG. 9 represents the relative standard deviation value corresponding to the amount of optical noise.

[0106] FIG. 9(a) shows the optical noise characteristics when the diffuser is not placed. Also, FIG. 9(b) shows the optical noise characteristics when a diffuser 488 having an average roughness “Ra” of 1.51 μm is placed inside the light source unit 2 (for example, the placement position of the diffuser 488 in FIG. 16). As shown in the “Prior Art Column” at the left end of FIG. 9(a) and FIG. 9(b), just by inserting the diffuser 488 alone (FIG. 9(b)), the optical noise is reduced compared to the prior case (FIG. 9(a)).

[0107] The region in FIG. 9 where the number of optical path divisions (value of PuwS_M) is 2 or more shows the effect when the operation / control of the phase synchronization characteristics and the operation / control of the phase characteristics (wavefront characteristics) are used in combination. FIG. 9(a) within this region shows the state of reduction of optical noise when only the operation / control of the phase synchronization characteristics is performed without using the diffuser 488 (that is, when only the optical path length conversion element is placed in the optical path). Even in FIG. 9(a) within this region, it can be seen that the amount of optical noise decreases as the number of region divisions (wavefront division number or optical path division number, value of PuwS_M) where the optical path length difference occurs increases. Furthermore, in FIG. 9(b) obtained by using the diffuser 488 for performing the operation / control of the phase characteristics (wavefront characteristics) in combination, the amount of optical noise is reduced compared to FIG. 9(a).

[0108] FIG. 10 shows a mechanism for reducing the amount of optical noise by using the operation / control of phase characteristics (wavefront characteristics), taking an expansion plate as an example. When a single initial wave train 400 passes through the diffuser plate 488, it is divided into a plurality of wave trains 430-0, -1, -2 with different phases from each other (the detailed principle will be described later). Then, the optical noise generated during the passage of the wave train 430-0 in the optical path interferes with the optical noise generated during the passage of the wave trains 430-1 and 430-2 in the optical path, respectively. As a result, it is considered that the amount of optical noise is reduced.

[0109] As shown in FIG. 4, as a specific example 270 of an optical property conversion element that performs the operation / control of phase characteristics (wavefront characteristics), in addition to the diffuser plate, there are diffraction gratings / holograms, various aberration generating elements, stepped plates, and the like. Even the above-mentioned optical property conversion elements other than the diffuser plate cause the above-described wave train division and reduce the amount of optical noise.

[0110] By the function of various optical property conversion elements that perform the operation / control of phase characteristics (wavefront characteristics), the wave train division for the initial wave train 400 and the amount of phase shift between the divided multiple wave trains 430-0, -1, -2 are set. Various operation / control parameters 280 for controlling the optical properties of the obtained predetermined light 230 are collectively described in FIG. 4.

[0111] However, simply controlling the values of the operation / control parameters 280 described in FIG. 4 has limitations in the range of optical properties of the predetermined light 230 that can be controlled. Therefore, in this embodiment, as shown in FIG. 3, the inside of the optical property conversion element 210 is divided into a plurality of regions 212 to 216, and the values of different operation / control parameters 280 can be set for each of the regions 212 to 216. Based on this, the range of optical properties of the predetermined light 230 that can be controlled by a single optical property conversion element 210 is greatly expanded. As a result, when using the optical property conversion element 210 having a structure divided into a plurality of regions 212 to 216, the ease of realizing the (desirable) optical property content required for each optical application field described in FIG. 2 is greatly improved.

[0112] Using an example of FIG. 10, a specific effect example of the optical property conversion element 210 having a structure divided into a plurality of regions 212 to 216 will be described. In the first light 202 that has passed through the first region 212 in the optical property conversion element 210, it is considered that three wave trains 430-0, -1, -2 with different phases as shown in FIGS. 10(d), 10(f), and 10(h) are generated. Further, the value of the operation / control parameter 280 is changed between the first region 212 and the second region 214. Therefore, the phases of the three wave trains separated and generated in the second light 204 that has passed through the second region 214 are different from the phases of the wave trains 430-0, -1, -2 in the first light 202. As a result of synthesizing all the wave trains at the photosynthesis location 220, the predetermined light 230 contains six wave trains with different phases from each other (a total of nine wave trains when considering the third light 206 that has passed through the third region 216). When the number of wave trains with different phases from each other in the predetermined light 230 increases in this way, the effect of reducing the amount of optical noise is further improved.

[0113] As shown by the experimental results of FIG. 9, by combining the operation / control of the phase characteristics (wavefront characteristics) and the operation / control of the phase synchronization characteristics, the averaging effect between optical noises increases. Furthermore, not only that, but with this combination, it becomes possible to reduce the coherence of the predetermined light 230. The basic concept regarding that technical device will be described below.

[0114] For example, if an interference generation path exists in the optical path through which a light beam with the same wavelength and the same phase travels, an interference fringe pattern in which the intensity periodically changes appears in the cross section image and spectroscopic characteristics of the light beam. By the way, if the interference generation path is appropriately set, interference fringes can be observed not only in the distant region 180 but also on the condensing surface / image forming surface and in the vicinity 170 thereof.

[0115] In the world of optics, the value obtained by dividing the difference between the maximum intensity and the minimum intensity within this interference fringe by the average intensity is defined as the "Visibility" "SV". Specifically, it is defined by the middle side of Equation 13. And often, the degree of coherence of light is evaluated by the value of this "Visibility" "SV".

[0116] When "operation / control of phase characteristics (wavefront characteristics)" is performed in the optical path before the above interference generation path, a phenomenon of coexistence of the same-wavelength light with different phases occurs within the predetermined light 230. Then, as shown in Equation 22 described later, the position of the light intensity strength within the interference fringe shifts according to the change in this phase amount. Furthermore, by adding "operation / control of phase synchronization characteristics", the coexistence amount of light with different phases increases (that is, the total number of elements of the light with different phases coexisting within the predetermined light 230 increases).

[0117] When such a plurality of interference fringes shifted from each other overlap, a canceling effect of the light intensity strength occurs between the individual interference fringes, and as a whole, the value of the visibility decreases. And this decrease in the visibility value is evaluated as a decrease in the degree of coherence of the predetermined light 230.

[0118] In particular, when "operation / control of phase synchronization characteristics" is first performed according to the light propagation direction 348, then "operation / control of phase characteristics (wavefront characteristics)" is performed, and then the photosynthesis location 220 is arranged, the effects of the above-described optical actions are improved (specific examples of the arrangement will be described later with reference to FIGS. 16 and 17A / B). The light 202 to 206 subjected to "operation / control of phase characteristics (wavefront characteristics)" may have some divergence (the directivity in which the propagation directions of all the light coincide is slightly reduced). Therefore, performing "operation / control of phase characteristics (wavefront characteristics)" after performing "operation / control of phase synchronization characteristics" in a state where the directivity of the light is high improves the optical noise reduction effect and the coherence reduction effect.

[0119] When the coherence is reduced as described above, among the optical characteristic contents 102 required (desired) for each optical application field shown in FIG. 2, "reduction of speckle noise", "reduction of return light noise (laser mode hopping noise)", "improvement of uniformity of irradiation light amount", "improvement of emission amount stability", "improvement of uniformity of illuminance", etc. are achieved. This effect is commonly obtained for both full-color light and single-wavelength light.

[0120] Even when reducing the coherence of the predetermined light 230 by combining the operation / control of the phase characteristic (wavefront characteristic) and the operation / control of the phase synchronization characteristic, if the inside of the optical characteristic conversion element 210 that performs the operation / control of the phase characteristic (wavefront characteristic) is composed of a plurality of regions 212 to 216 set to values of different operation / control parameters 280, the coherence reduction effect is further improved. That is, the individual operation / control parameters 280 in the plurality of regions 212 to 216 can be flexibly set so as to best match the optical characteristic contents 102 required (desired) for each optical application field shown in FIG. 2.

[0121] Regarding the basic concept of the technical idea in the above-described embodiment, it will be described theoretically and specifically below. For simplicity of explanation below, it will be described as an example of single-wavelength light having a central wavelength of "λ0" and a wavelength range of "Δλ". However, it is not limited thereto, and for example, the following description content can also be applied to full-color light or white light. Here, the characteristics of individual wavelength lights obtained after splitting full-color light or white light with a spectroscope correspond to the following description content. As a specific correspondence relationship, the detection wavelength for each detection cell of the spectroscope corresponds to "λ0", and the wavelength resolution of the spectroscope corresponds to "Δλ".

[0122] Taking "interference generation between the direct light and the front and back surface reflected lights of a parallel transparent plate or transparent sheet" as a specific example of the above-described interference generation path, theoretical analysis is performed. Next, the form of this interference generation path is generalized, and the optical noise reduction phenomenon when performing "operation / control of phase synchronization characteristic" during optical noise generation is quantitatively explained.

[0123] After that, the "phase separation model" of the light passing through the diffuser plate is explained, and the decrease phenomenon of the visibility value when "operation / control of phase synchronization characteristics" and "operation / control of phase characteristics (wavefront characteristics)" are combined is quantitatively explained.

[0124] The refractive index of a transparent plate or transparent sheet with parallel front and back surfaces is represented by "n", and the thickness "d" of the front and back surfaces is described as "d0 + δd". The arrival time difference "τ" between the in-phase positions generated between the direct light (j = 0) of this transparent plate or transparent sheet and the light reflected once at the front and back surfaces (j = 1) j ” is

[0125]

Equation

[0126] Between the wavelength width "Δλ" of the central wavelength "λ0" and the corresponding frequency width "Δν",

[0127]

Equation

[0128]

Equation

[0129]

Equation

[0130] The amplitude characteristics of the synthesized light (predetermined light 230) obtained when the initial light 200 having the central frequency "ν0" and the frequency width "Δν" passes through a transparent plate or transparent sheet with a thickness range "Δd" are

[0131]

Equation

[0132]

Number

[0133]

Number

[0134]

Number

[0135]

Number

[0136]

Number

[0137] The cosine function shown in the third term on the right side of Equation 11 indicates a “periodic light quantity change” corresponding to the change amount of the wavelength “λ0”. Therefore, this cosine function part contributes to the generation of the interference fringe pattern in the spectral characteristics.

[0138] And corresponding to the above “periodic light quantity change amount”, the aforementioned visibility “SV” is

[0139] [Number] is defined. Here, "|μ τ 01 |", means the degree of coherence of the light described above. Then, substituting Equation 11 into Equation 12,

[0140] [Number] is obtained.

[0141] So far, the analysis of the interference fringe generation phenomenon has been carried out when a transparent plate or a transparent sheet parallel to the interference generation path is arranged. Next, the concept of this analysis result is extended to set an optical noise generation model. That is, it is assumed that some interference generation path occurs in the optical path of a single-wavelength light beam with synchronized (coincident) phases. Here, based on the optical interference generated here, the superposition of multiple types of interference fringes appearing in the cross-sectional image or spectral characteristics of the light beam is regarded as the cause of the generation of optical noise, and an analysis model is established.

[0142] In this case, instead of a transparent plate or a transparent sheet having a predetermined thickness range "Δd", a minute optical path length difference change range "(n - 1)Δd" occurring within a specific interference generation path is assumed. Therefore, as a mathematical model of the location where optical noise is generated, instead of Equation 10,

[0143] [Number] is used.

[0144] In the optical noise generation model assumed here, A) Initial light 200 with an amplitude value of "1" is incident into the interference generation path B) At the j-th optical noise generation location, the amplitude "E jOptical noise generating light of "" occurs C) As a result of the initial light 200 traveling through the interference generation path, the amplitude is "E0 = 1 - SUM(E j )" and decreases D) Interference occurs between the light with the amplitude attenuated to "E0" and each optical noise generating light with the amplitude "E j ", generating optical noise. Assume this. From the assumption in [C] above,

[0145]

Equation

[0146] The intensity of the light passing through the m-th region in the optical path length conversion element (optical property conversion element 210 that performs operation / control of phase synchronization characteristics) is represented by "<I Rm >". The characteristic formula of this "<I Rm >" is In Equation 11, replace "Dp0" with "E0D0", and further replace "R 2 Dp1" with "E j D j >", and replace "2d0" with "χ mj >". It is given by the resulting equation.

[0147] Since there is a relationship of mutual phase asynchrony 402 between the wave trains 406 and 408 that pass through each region in the optical path length conversion element individually, the characteristic formula of the predetermined light 230 after being synthesized at the light synthesis location 220 is given by the simple addition of each intensity characteristic. Assuming the number of regions (wavefront division number or optical path division number, the value of PuwS_M) divided in the optical path length conversion element is "M", the characteristic formula of the predetermined light 230 is

[0148]

Equation

[0149] Increasing the number "M" of regions in Equation 16 results in the following in the limit state

[0150]

Number

[0151]

Number

[0152] Based on the findings obtained above, next, an operation analysis of the optical property conversion element 210 that operates / controls the phase characteristics (wavefront characteristics) such as a diffusion plate is performed. Fig. 10(b) shows the surface roughness distribution characteristics of the diffusion plate. According to statistical theory, it is known that this surface roughness distribution characteristic is similar to a "Gaussian distribution". Fig. 10(b) can be approximated as a combination of three stacked rectangular distributions shown in Fig. 10(c), (e), and (g). Here, the important point is that, unlike a completely symmetric Gaussian distribution, the surface roughness distribution characteristic of an actual diffusion plate deviates from perfect left-right symmetry. Taking the center position of the uppermost rectangular distribution shown in Fig. 10(c) as a reference, the deviation amount of the center position of the middle rectangular distribution shown in Fig. 10(e) is expressed as "χ1". Similarly, the deviation amount of the center position of the lowermost rectangular distribution shown in Fig. 10(g) is shown as "χ2". And the amplitude value of the initial wave train 400 with an amplitude value of "1" in Fig. 10(a) after passing through the rectangular distribution of the "l-th stage" (l≧0) from above is approximated as "E l D l ".

[0153] That is, in the first light 202 that has passed through the first region 212 in the optical property conversion element 210 that operates / controls the phase characteristics (wavefront characteristics), there are a plurality of wave trains 430-0~-2 with an amplitude value of "E l D l " and a phase value of "χ l ". And when it has a structure divided into a plurality of regions 212~216 like the optical property conversion element 210 in Fig. 3, the generated predetermined light 230 synthesized at the light synthesis location 220 contains even more wave trains.

[0154] And the intensity characteristic of this predetermined light 230 is that "(E0D0)" in Equation 16 2 " is replaced by "SUM{(E l D l ) 2It can be expressed by a mathematical formula changed to "}”. However, in this case, the subscript "m" means the region number in the optical property conversion element 210 that performs the operation / control of the phase property (wavefront property). Also, the variable "M" means the total number of areas in the optical property conversion element 210 that performs the operation / control of the phase property (wavefront property).

[0155] In this case as well, the same "averaging effect" as in Equation 17 works, and in the limit state

[0156] [Number] the approximate formula of holds. Considering the process of change of the mathematical formula leading to this Equation 19, 'The optical property conversion element 270 that performs the operation / control of the phase property (wavefront property) including the diffusion plate has the property of increasing optical noise by itself', but when the optical property conversion element 270 is composed of a plurality of regions 212 to 216 with different operation / control parameters 280 as shown in FIG. 3, it can be seen that 'the optical noise is reduced'. Moreover, not only that, it can also be said that 'the optical noise is reduced' by combining 'the optical property conversion element 270 that performs the operation / control of the phase property (wavefront property) including the diffusion plate' and 'the optical path length conversion element (the optical property conversion element 210 that performs the operation / control of the phase synchronization property)'.

[0157] Next, the operating principle of reducing the coherence by combining 'the optical property conversion element 270 that performs the operation / control of the phase property (wavefront property) including the diffusion plate' and 'the optical path length conversion element (the optical property conversion element 210 that performs the operation / control of the phase synchronization property)' will be explained. For the sake of simplicity of explanation, here, the case where only the first region 212 is included in the optical property conversion element 210 that performs the operation / control of the phase property (wavefront property) such as the diffusion plate will be explained. However, although the detailed explanation is omitted, when the optical property conversion element 210 that performs the operation / control of the phase property (wavefront property) is composed of a plurality of regions 212 to 216 as shown in FIG. 3, the effect of reducing the coherence is further enhanced.

[0158] Here, consider the case where light passing through the m-th region in the optical path length conversion element divided into “M” regions passes through a diffuser plate (optical property conversion element 210 that operates / controls phase characteristics (wavefront characteristics)) composed only of the first region 212. In this case, as shown in FIG. 10, after passing through the rectangular distribution of the “l-th stage” (l ≧ 0) from the top, a phase difference of “χ ml ” occurs. Even for the same diffuser plate (optical property conversion element 210 that operates / controls phase characteristics (wavefront characteristics)), the phase difference “χ ml ” changes according to slight variations for each optical path passing through it. Thus, the phase characteristics change sensitively depending on the difference in the optical path.

[0159] In contrast, the amount of amplitude change depending on the difference in the optical path is considered to be very small. That is, the amplitude value of the initial wave train 400 with an amplitude value of “1 / √M” in FIG. 10(a) after passing through the rectangular distribution of the “l-th stage” can be approximated to “E l D l / √M” regardless of the passing region number in the optical path length conversion element.

[0160] And the amplitude characteristics after each light passing through the above diffuser plate passes through the “transparent plate or transparent sheet with parallel front and back surfaces” described by Equation 8 are

[0161]

Equation

[0162] Next, calculate the spectral characteristics after the individual lights represented by Equation 20 are combined into the predetermined light 230 at the photosynthesis location 220. The spectral characteristics are generally expressed as the ratio of the “detected spectral intensity characteristics” to the “spectral intensity characteristics of the reference light used as a reference”. Here, the spectral intensity characteristics of the predetermined light 230 passing through the “optical path length conversion element” ⇒ “diffuser plate” ⇒ “photosynthesis location 220” are treated as the spectral intensity characteristics of the reference light. And the spectral intensity characteristics of the reference light in this case can be approximated by Equation 19.

[0163] When a "transparent plate or transparent sheet with parallel front and back surfaces" is inserted in the optical path of this reference light, the spectral intensity characteristics obtained are treated as the "detected spectral intensity characteristics". And the spectral characteristics calculated here are

[0164]

Equation

[0165]

Equation

[0166] And the interference fringe characteristics (the original visibility "SVorg(λ0)" represented by Equation 13) obtained by the interference of the direct light of the parallel transparent plate or transparent sheet and the reflected light on the front and back surfaces overlap with the second term group on the right side of Equation 22. Especially when the value of Equation 19 is small, the value of the second term group on the right side of Equation 22 increases as a whole. As a result, the "averaging effect" works, and the value of the overall visibility "SVdiff(λ0)" decreases.

[0167] As a ratio of the visibility “SVdiff(λ0)” obtained when using the optical property conversion element 210 with respect to the original visibility “SVorg(λ0)” represented by the mathematical expression 13, the following relative coherence degree “SVR(λ0)” is defined.

[0168] [Number]

[0169] FIG. 11 shows the results of a demonstration experiment regarding the coherence reduction effect of the predetermined light 230 when using the optical property conversion element 210 used in the present embodiment. FIG. 11(a) shows the change in the relative coherence degree when only the diffusion plates 488 with different average roughness “Ra” are arranged inside the light source unit 2 (the arrangement position of the diffusion plate 488 in FIG. 16). It can be seen that as the average roughness of the diffusion plate 488 increases, the relative coherence degree decreases, and the effect of the optical property conversion element 210 that operates / controls the phase characteristics (wavefront characteristics) can be understood.

[0170] FIG. 11(b) shows the change in the relative coherence degree when an optical property conversion element 210 that operates / controls the phase synchronization characteristics is additionally arranged (at the arrangement position of the wavefront multi-division optical path length conversion element 360 in FIG. 16). It can be seen that when an optical property conversion element 210 that operates / controls the phase synchronization characteristics is used in combination with an optical property conversion element 210 that operates / controls the phase characteristics (wavefront characteristics), the coherence reduction effect of the predetermined light 230 increases.

[0171] In the above theoretical analysis and demonstration experiment of the effect, the characteristics when using the diffusion plate 488 are taken as an example. However, not limited to the above diffusion plate 488, the same effect can be obtained for other optical property conversion elements 210 that operate / control the phase characteristics (wavefront characteristics).

[0172] Chapter 4 Characteristic Evaluation Method in the Present Embodiment It was explained in Chapter 3 that the predetermined light 230 formed in the present embodiment has reduced optical noise or coherence compared to the initial light 200. As a result, the predetermined light 230 has the (desirable) optical characteristics required for each optical application field shown in FIG. 2 compared to the conventional initial light 200.

[0173] In this chapter, a characteristic evaluation method for determining whether the predetermined light 230 formed in the present embodiment has the (desirable) optical characteristics required for each optical application field shown in FIG. 2 will be described. That is, if at least any one of the present embodiments is implemented (adopted) and the evaluation result in the characteristic evaluation method described below satisfies a predetermined determination condition, it can be evaluated as "conforming to the present embodiment".

[0174] The predetermined light 230 formed in the present embodiment basically A) Spectral characteristics or B) Imaging image characteristics is used for evaluation. Also, the light in a situation where at least any one of the present embodiments is not implemented is defined as "initial light 200", and the light obtained by implementing at least any one of the present embodiments is defined as "predetermined light 230". Then, the optical characteristics of the "initial light 200" and the "predetermined light 230" are measured by the same characteristic evaluation method, and the measurement results are compared to evaluate the presence or absence of differences between the two.

[0175] As an evaluation method for reducing the amount of optical noise, the method shown in FIG. 9 is adopted. That is, an optical system composed of the light source unit 2 and the measurement unit 8 shown in FIG. 1 may be configured, and the amount of optical noise generated in the optical system may be evaluated. Here, the "initial light 200" and the "predetermined light 230" are switched depending on whether at least any one of the techniques described in the present embodiment is adopted in the light source unit 2 (including the optical characteristic conversion block 390 arranged in the optical propagation path 6). Alternatively, as was done during data measurement in FIG. 9, the optical characteristics when phase characteristic (wavefront characteristic) operation / control elements such as a diffuser plate 488 or a diffraction grating / hologram are inserted into a part of the optical system (for example, in the optical propagation path 6) to "intentionally generate optical noise" may be compared.

[0176] As the optical characteristic evaluation value, a "relative standard deviation value" may be used in the same manner as in FIG. 9. The calculation procedure of this "relative standard deviation value" will be described below. That is, 1. Average the data obtained in the above "A) Spectral characteristics" or "B) Imaging image characteristics" to calculate the "average value characteristic". 2. Calculate the difference between the above “A) Spectral characteristics” or “B) Imaging image characteristics” and the above “Average value characteristics” as the “Individual displacement amount”. 3. Define the ratio of the above “Individual displacement amount” to the above “Average value characteristics” (that is, the value obtained by dividing the “Individual displacement amount” by the “Average value characteristics”) as the “Relative displacement amount”. 4. Perform statistical analysis on the distribution of the “Relative displacement amount” (perform “Normalization” approximated to a normal distribution), and calculate the standard deviation value of (the approximated normal distribution) as the “Relative standard deviation value”.

[0177] The “Prior art” in Fig. 9(a) shows the characteristics of the “Initial light 200”. And the other data shows the optical characteristics obtained from the “Predetermined light 230” obtained by adopting the individual technologies described in this embodiment. Comparing Fig. 9(a) and Fig. 9(b) in the “Prior art”, the “Relative standard deviation value” obtained from the “Predetermined light 230” is reduced by about 20% compared to the “Relative standard deviation value” obtained from the “Initial light 200”. Therefore, compare the “Relative standard deviation value” obtained from the “Initial light 200” with the “Relative standard deviation value” obtained from the “Predetermined light 230”, and consider that “the effect is achieved in a state where it is reduced by 20% or more (when this embodiment is implemented)”.

[0178] On the other hand, in the case of the “Prior art” in Fig. 9(a) and the optical path division number being “2”, it is only reduced by about 5%. Therefore, when judged strictly, it may also be considered that “the effect is achieved in a state where it is reduced by 5% or more (when this embodiment is implemented)”.

[0179] Fig. 9 shows the comparison data of the “A) Spectral characteristics”. However, it is not limited to this, and it may also be evaluated using the “B) Imaging image characteristics” caused by the optical noise appearing in the imaging image detected by the imaging device 300. In this case, the “Relative standard deviation value” is also calculated by the same method as above, and consider that “the effect is achieved in a state where it is reduced by 20% or more (when this embodiment is implemented)”, or judge strictly and consider that “the effect is achieved in a state where it is reduced by 5% or more (when this embodiment is implemented)”.

[0180] Calculating and comparing the above-mentioned 'relative standard deviation value' results in the highest evaluation accuracy. However, performing statistical analysis (normalization of the 'relative displacement distribution') for this purpose imposes a large burden. Therefore, instead of calculating the exact 'relative standard deviation value', one can examine the 'amplitude value of the noise component' that is considered to be caused by optical noise among 'A) Spectral characteristics' or 'B) Imaging image characteristics', and compare the data obtained from the 'initial light 200' with the data obtained from the 'predetermined light 230' to evaluate the effect. In this case, the 'amplitude value' within 'A) Spectral characteristics' or 'B) Imaging image characteristics' can be compared, 'The effect is present in a state where it has decreased by 20% or more (when this embodiment is implemented)', or by strictly judging it may be regarded as 'the effect is present in a state where it has decreased by 5% or more (when this embodiment is implemented)'.

[0181] FIG. 12 shows comparison data of speckle noise generated based on coherence. FIG. 12(a) shows the intensity distribution of a cross-section of an imaging image obtained from a non-mirror surface (a general light-scattering surface) irradiated with the 'initial light 200' in a parallel light beam state. Here, as the non-mirror surface, for example, any surface that scatters light such as plain paper, a wall, or skin can be used. Similarly, FIG. 12(b) shows the intensity distribution of a cross-section of an imaging image obtained from a non-mirror surface irradiated with the 'predetermined light 230'.

[0182] In the world of laser interference, an index called speckle contrast is used to evaluate this coherence. Here, the above-mentioned speckle contrast uses substantially the same definition formula as the above-mentioned'relative standard deviation value'. That is, 'Ia(x)' in FIG. 12 means the above-mentioned 'average value characteristic'. Also, 'dI(x)' in FIG. 12 corresponds to the above-mentioned 'individual displacement amount'.

[0183] When using the "initial light 200", the speckle contrast value obtained in Fig. 12(a) was "9.85%". On the other hand, when using the "predetermined light 230", the speckle contrast value obtained in Fig. 12(b) was "6.39%". Therefore, it can be seen that when using the "predetermined light 230", the speckle contrast value decreases by approximately 40%. Considering the above optical noise reduction results and examining the above data, a determination criterion for the effect is set with a certain margin. That is, by comparing the speckle contrast values, "The effect is present when the reduction is 20% or more (when this embodiment is implemented)", or strictly judging "The effect is present when the reduction is 5% or more (when this embodiment is implemented)".

[0184] The measurement data shown in Fig. 12 is the data measured as "B) Imaging image characteristics". However, it is not limited to this, and the optical characteristics may be measured in the form of "A) Spectral characteristics". In this case, the "initial light 200" or "predetermined light 230" in a parallel light beam state is irradiated onto a non-specular surface (a general light scattering surface), and the speckle contrast value may be calculated in the same manner from the distribution of the "A) Spectral characteristics" obtained from the non-specular surface.

[0185] Also, calculating and comparing the above-mentioned speckle contrast for the evaluation of coherence results in the highest evaluation accuracy. However, doing so up to statistical analysis (normalization of the "relative displacement amount distribution") is a heavy burden. Therefore, instead of calculating the exact speckle contrast, the "amplitude value of the noise component" that is considered to be caused by speckle noise in the "A) Spectral characteristics" or "B) Imaging image characteristics" is examined, and the data obtained from the "initial light 200" and the data obtained from the "predetermined light 230" are compared to evaluate the effect. In this case, by comparing the "amplitude values" within the "A) Spectral characteristics" or "B) Imaging image characteristics", "The effect is present when the reduction is 20% or more (when this embodiment is implemented)", or strictly judging "The effect is present when the reduction is 5% or more (when this embodiment is implemented)" may also be regarded.

[0186] The method for evaluating / judging the optical characteristics of the "predetermined light 230" has been described up to this point. Next, a method for evaluating and a method for judging the optical characteristics of each optical characteristic conversion element 210 will be described. That is, an optical system incorporating the optical characteristic conversion element 210 whose measurement results obtained by the following evaluation method satisfy the following judgment conditions is considered to be using at least a part of the present embodiment.

[0187] FIG. 13 shows an example of the RMS value of the wavefront aberration obtained as a measurement result. FIG. 13 shows the RMS value of the wavefront aberration of the light that has passed through the wavefront multi-division optical path length conversion element 360 (see FIG. 16) that has been "divided into 8 in the angular direction" (without division in the radial direction). As a specific evaluation / measurement method, the wavefront characteristics of the light that has passed through or been reflected by the optical characteristic conversion element 210 are measured using a transmission-type or reflection-type interferometer, and the RMS value is calculated.

[0188] According to the content already described with reference to FIG. 6D, the value of the wavefront accuracy of the light that has passed through or been reflected by the optical characteristic conversion element 210 is "Implementing the present embodiment when it is 0.5λ or more and 100λ or less", or more precisely "Considered to be implementing the present embodiment when it is 0.3λ or more and 1000λ or less". Here, the value of the wavelength "λ" is set to "400 nm".

[0189] As already described with reference to FIGS. 6A to 6C, when using the optical characteristic conversion element 210 that operates / controls the phase characteristic (wavefront characteristic), the divergence angle of the light that has passed through here becomes important. FIG. 14 shows the measurement / evaluation method and the judgment criteria of the optical characteristic conversion element 210 regarding the divergence angle of the light. When the initial light 200 passes through the first region 212, it has a divergence angle of "θ1" in the first optical path 222. On the other hand, when the initial light 200 passes through the second region 214, it has a divergence angle of "θ2" in the second optical path 222. The divergence angle "θ" is obtained from the half-value width 198 of the intensity distribution of the light projected onto the screen 326 disposed at a position a predetermined distance away from the optical property conversion element 210. Here, a mask pack 328 that partially blocks light is disposed immediately in front of the optical property conversion element 210, and by comparing the half-value width 198 when not blocking light with the half-value width 198 when only the first region 212 is blocked and the half-value width 198 when only the second region 214 is blocked, the respective divergence angles "θ1" and "θ2" are obtained. In the present embodiment, as the relationship between the divergence angles "θ1" and "θ2", 'This embodiment is implemented when 1.2 ≤ θ1 / θ2 ≤ 1000', or more precisely 'This embodiment is considered to be implemented when 1.5 ≤ θ1 / θ2 ≤ 100'.

[0190] FIG. 15 shows an example of the measurement result of the spectral characteristics of the light transmitted through the optical property conversion element 210 that manipulates / controls the phase characteristics (wavefront characteristics). FIG. 15(a) shows the measurement result of the spectral characteristics of the optical property conversion element 210 composed only of the first region 212. As the measurement wavelength increases, the light transmission intensity increases rapidly. On the other hand, FIG. 15(b) shows the measurement result of the spectral characteristics of the optical property conversion element 210 composed of a combination of the first region 212 and the second region 214 with different roughness average values "Ra". A significant difference in spectral characteristics is shown compared to FIG. 15(a).

[0191] Here, the data in FIG. 15(a) is regarded as the data obtained from the 'initial light 200'. And the data in FIG. 15(b) is regarded as the data obtained from the 'predetermined light 230' and the characteristics of the two are compared. The difference in the effects of the two is evaluated by the relative change amount "Δ(λ)" of the light transmission intensity at an arbitrary wavelength with respect to the data in FIG. 15(a). Following the above-described evaluation method, the value obtained by dividing the 'absolute change amount of the light transmission intensity' by the 'light transmission intensity obtained from the initial light 200' at the same wavelength is defined as the'relative change amount "Δ(λ)" of the light transmission intensity'. And in this relative change amount "Δ(λ)" of the light transmission intensity, "It has an effect in a state where it has changed by 20% or more (when this embodiment is implemented)", or strictly judged as "It is regarded as having an effect in a state where it has changed by 5% or more (when this embodiment is implemented)".

[0192] Chapter 5 Specific Examples Inside the Light Source Unit and Inside the Optical Characteristic Conversion Block In Chapter 2, an overview of the basic optical action in this embodiment was explained. Specific examples in the optical characteristic conversion block 390 included in the light source unit 2 or, more broadly interpreted, a part of the light source unit 2 by combining the individual element technologies described in Chapter 2 will be described.

[0193] FIG. 16 shows a specific example inside the light source unit 2 when an incandescent light source is used as the light emitting source. For example, the surface of a heat-generating lamp 472 such as a halogen lamp or a mercury lamp becomes hot. On the other hand, the optical system for exerting the effects described in Chapter 3 dislikes the entry of dust, dirt, and contamination in the optical path. In the structural overview shown in FIG. 16(b), the light emitting unit 470 that houses the incandescent lamp 472 and the optical characteristic control unit 480 are mechanically separated. Then, an optical fiber 330 is connected to the outlet of this optical characteristic control unit 480. By using the optical fiber 330 that is highly flexible mechanically, the light output from the optical characteristic control unit 480 can be guided to an arbitrary location. Further, as shown in FIGS. 16(a) and 16(c), a heat insulating plate 476 is arranged between the light emitting unit 470 and the optical characteristic control unit 480 to block heat conduction between the two. Further, the periphery of the optical characteristic control unit 480 is covered to block the flow of air from the outside. By adopting this structure, the entry of dust, dirt, and contamination into the inside of the optical characteristic control unit 480 can be prevented. Further, by blocking the heat conduction of the heat insulating plate 476, the thermal deformation inside the optical characteristic control unit 480 generated by temperature changes can also be reduced.

[0194] By the way, the radiation light from the incandescent lamp 472 passes through the optical characteristic control unit 480. Therefore, a light transmissive medium is disposed on a part of the heat insulating plate 476. The radiation light from the incandescent lamp 472 passes through this light transmissive medium. On the other hand, the light transmissive medium disposed in the heat insulating plate 476 blocks the flow of air and heat from inside the light emitting unit 470 to inside the optical characteristic control unit 480. As the material of this light transmissive medium, a transparent resin (plastic) may be used. However, the transparent resin has a high light absorption rate in the near infrared region (for example, a wavelength of 1.6 μm or more). Therefore, when using the near infrared light obtained from the light source unit 2, it is desirable to use transparent glass or quartz glass as the material of the light transmissive medium.

[0195] As the shape of this light transmissive medium, a parallel flat plate can be used. In FIG. 16, an imaging lens 312 is used as the light transmissive medium, and the imaging lens 312 also functions as a condenser for the emitted light from the lamp 472 while blocking the flow of air and heat. By combining various functions in the imaging lens 312 in this way, the light source unit 2 itself can be simplified and its cost can be reduced.

[0196] Furthermore, the imaging lens 312 is disposed at a position deeper than the surrounding heat insulating plate 476. This prevents an operator from accidentally contacting the imaging lens 312 when replacing the lamp 472.

[0197] In FIG. 16, ND filters (neutral density filters) 492 and 494, band pass filters or high pass filters 496, and band pass filters or low pass filters 498 are disposed as the light transmissive medium disposed at the boundary between the light emitting unit 470 and the optical characteristic control unit 480.

[0198] The amount of light and the spectral characteristics of the radiation light from the incandescent lamp 472 change with the filament temperature in the lamp 472. Therefore, from immediately after the start of lighting of the incandescent lamp 472 until the filament temperature stabilizes, the amount of light and the spectral characteristics of the radiation light change with the passage of time. In order to stabilize the light emission amount of this radiation light, the light emission amounts are detected by the photodetectors 482-1 and 482-2, and the current value supplied to the incandescent lamp 472 is controlled.

[0199] Particularly in the case of the incandescent lamp 472, it has a spectral characteristic in which the long-wavelength intensity increases as the filament temperature rises. Therefore, for example, when measuring using both visible light and near-infrared light emitted from this light source unit 2, it is desirable to simultaneously detect the emission amounts in both the wavelength range of visible light and the wavelength range of near-infrared light for light quantity control. For this purpose, a photodetector 482-1 that detects only the near-infrared light that has passed through a band-pass filter or a high-pass filter 496 and a photodetector 482-2 that detects only the visible light that has passed through a band-pass filter or a low-pass filter 498 are arranged. Also, the detection sensitivities of the photodetector 482-1 for near-infrared light and the photodetector 482-2 for visible light are different from each other. For correcting this detection sensitivity, ND filters 492 and 494 are individually arranged.

[0200] Inside the light emitting unit 470, a concave mirror 474 is installed on the back surface of the lamp 472. Then, the light radiated in the back direction of the lamp 472 is reflected by the concave mirror 474 and passes through the filament gap inside the lamp 472 and then heads towards the imaging lens 312. In this way, the light radiated in the back direction of the lamp 472 is also effectively utilized to improve the utilization efficiency of the light radiated from the light source unit 2.

[0201] Inside the light emitting unit 470, two fans 478-1 and 478-2 are arranged to create an artificial air flow 442. Specifically, the upper fan 478-1 draws in outside air, and the rear fan 478-2 discharges the air inside the light emitting unit 470 to the outside. Particularly, by having a part of this air flow 442 directly hit the lamp 472, the heat dissipation effect of the lamp 472 is enhanced. On the other hand, this air flow 442 is arranged so as not to directly hit the imaging lens 312 or the ND filters 402 and 494. Thus, a measure is taken to prevent dust and dirt entrained in the air flow 442 from adhering to the imaging lens 312 or the ND filters 402 and 494.

[0202] Also, louver windows 440-1 and 440-2 are installed outside each of the fans 478-1 and -2 so that the radiated light does not leak outside from the intake port of the upper fan 478-1 and the discharge port of the rear fan 478-2.

[0203] Since it becomes extremely hot around the incandescent lamp 472 during light emission, a technical ingenuity is required for a stable fixing method of the lamp 472. The lamp fixing part 446 formed of a material having excellent heat insulation effect and low coefficient of thermal expansion supports the lamp base 473 to fix the position of the incandescent lamp 472. Particularly, due to the large temperature change between the lighting / extinguishing of the incandescent lamp 472, large thermal expansion and thermal contraction of the lamp base 473 are repeated. To prevent the position of the lamp 472 from shifting due to the repeated thermal expansion / thermal contraction of this lamp base 473, the lamp fixing part 446 itself is given shape elasticity, and a slidable structure is provided between the lamp fixing part 446 and the lamp base 473. This lamp fixing part 446 can be finely adjusted by the fine movement mechanism 448 of the lamp to finely adjust the position of the lamp 472 in the light emitting part 470.

[0204] The optical characteristic control part 480 is provided with an aperture control part 484 having a small aperture. And the imaging lens 312 projects (images) the imaging pattern of the filament in the lamp 472 onto the surface of the aperture control part 484. And only the central part in this imaging pattern passes through the aperture in the aperture control part 484. By providing the aperture control part 484 in the optical characteristic control part 480 in this way, an ideal optical path (optical axis) of the emitted light from the lamp 472 is defined. That is, the emitted light passing through an optical path greatly deviated from the ideal optical path (optical axis) is blocked by the aperture control part 484. By the function of this aperture control part 484, unnecessary wavefront aberration generated in the middle of the optical path is prevented. As a result, the optical characteristics described in Chapter 3 can be effectively exhibited.

[0205] For example, if the position of the lamp 472 is greatly deviated from the central position in the light emitting part 470 without installing the aperture control part 484, large coma aberration occurs when the emitted light from the lamp 472 passes through the imaging lens 312, the collimating lens 318, and the condenser lens 314. Unnecessary wavefront aberration such as coma aberration generated here causes large characteristic variations during mass production of the light source unit 2.

[0206] The size of the filament in the incandescent lamp 472 is relatively large. Therefore, even if the position of the lamp 472 is installed near the center position within the light emitting part 470, the light emitting position of the peripheral part of the filament deviates slightly from the ideal optical axis. For this reason, the radiation light from the peripheral part of the filament generates some coma aberration when passing through the imaging lens 312 and the collimating lens 318. Therefore, the aperture control unit 484 shields the radiation light from the peripheral part of the filament and uses only the radiation light with less wavefront aberration.

[0207] The radiation light passing through the aperture of the aperture control unit 484 is converted into a substantially parallel light beam after passing through the collimating lens 318. In the optical path of this parallel light beam, a wavefront multi-division optical path length conversion element 360 for performing operation / control of phase synchronization characteristics is arranged. FIG. 16(d) shows a view of this wavefront multi-division optical path length conversion element 360 as seen from the direction of light propagation. As shown in FIG. 16(d), the inside of the wavefront multi-division optical path length conversion element 360 is divided into 12 parts in the angular direction and 4 parts in the radial direction, and it is a 48-division element already described in FIG. 7B. Two of the boundary lines divided into 12 parts in the angular direction are set at angles parallel to the horizontal axis 450 and the vertical axis 460, respectively. However, the specific shape of the wavefront multi-division optical path length conversion element 360 is not limited to this, and the 12-division element described in FIG. 7C or the 2-division element arranged in FIG. 7A may also be used. The light passing through this wavefront multi-division optical path length conversion element 360 is condensed by the condenser lens 314 and enters the optical fiber 330. A diffuser plate 488 is arranged in the optical path. Therefore, since the wavefront multi-division optical path length conversion element 360 and the diffuser plate 488 are used in combination within the optical characteristic control unit 480 in FIG. 16(c), both the phase synchronization characteristics and the phase characteristics (wavefront characteristics) are simultaneously operated / controlled.

[0208] FIG. 16(e) shows the surface state of this diffusion plate 488. A first light diffusion region 489-1 with a relatively small average value “Ra1” of surface roughness and its average period “Pa1” constitutes the first region 212. Compared therewith, a second light diffusion region 489-2 with a relatively large average value “Ra2” of surface roughness and its average period “Pa2” (satisfying the relationship “Ra2 / Ra1 > 1” and “Pa2 / Pa1 > 1”) constitutes the second region 214. Each of the first light diffusion region 489-1 and the second light diffusion region 489-2 forms a sector with a “central angle of 30 degrees” and is arranged alternately as shown in FIG. 16(e).

[0209] Particularly, the boundary line between the first light diffusion region 489-1 and the second light diffusion region 489-2 is inclined with respect to the boundary line that angularly divides within the multi-divided optical path length conversion element 360. That is, two of the boundary lines that angularly divide within the multi-divided optical path length conversion element 360 are parallel to the horizontal axis 450 and the vertical axis 460. In contrast, all the boundary lines between the first light diffusion region 489-1 and the second light diffusion region 489-2 have an inclined relationship with respect to the horizontal axis 450 and the vertical axis 460. That is, within an arbitrary region in the 48-divided wavefront multi-divided optical path length conversion element 360, the boundary line between the first light diffusion region 489-1 and the second light diffusion region 489-2 is arranged to exist.

[0210] Therefore, regarding the light passing through an arbitrary region in the 48-divided wavefront multi-divided optical path length conversion element 360, a part of it necessarily passes through the first light diffusion region 489-1, and the remaining part passes through the second light diffusion region 489-2. As a result, the effects described in Chapter 3 are efficiently exerted.

[0211] Particularly, when the area of the first light diffusion region 489-1 and the area of the second light diffusion region 489-2 are approximately equal within an arbitrary region in the 48-divided wavefront multi-divided optical path length conversion element 360, the effects described in Chapter 3 are significantly (maximally) exerted. Specifically, the effect is greatest when the angle formed by the "boundary line between the first light diffusion region 489-1 and the second light diffusion region 489-2" with respect to the "boundary line for angular division within the multi-divided optical path length conversion element 360" is "half" of the "angle for angular division within the multi-divided optical path length conversion element 360". That is, in FIG. 16(e), since the "angle for angular division within the multi-divided optical path length conversion element 360" is "30 degrees", a large effect can be obtained by arranging the boundary line between the first light diffusion region 489-1 and the second light diffusion region 489-2 to be inclined at "15 degrees" with respect to the horizontal axis 450 and the vertical axis 460.

[0212] FIGS. 17A and 17B show a structural example within the optical property conversion block 390 (optical property conversion block). Here, instead of constituting the light source unit 2 alone, this optical property conversion block 390 is arranged in the optical path of the initial light 200, and the optical properties of the initial light 200 can be operated / controlled.

[0213] In the optical property conversion block 390 shown in FIG. 17A, it is arranged in the far-field region 180 of the initial light 200 (for example, in the optical path of a parallel light beam) to generate the predetermined light 230 whose optical properties are operated / controlled. In this optical property conversion block 390 as well, both the phase synchronization property and the phase property (wavefront property) are simultaneously operated / controlled.

[0214] That is, the wavefront multi-division optical path length conversion element 360 is first arranged along the traveling direction of the initial light 200, and the phase synchronization characteristics are first manipulated / regulated. Thereafter, the diffusion plate 488 or diffraction grating or hologram is arranged, and the phase characteristics (wavefront characteristics) are manipulated / regulated. Inside the wavefront multi-division optical path length conversion element 360, substantially parallel light beams pass through. And since the light passing through the diffusion plate 488 or diffraction grating or hologram has various traveling directions, light synthesis is performed in the space immediately after passing through the diffusion plate 488 or diffraction grating or hologram. That is, the space immediately after passing through the diffusion plate 488 or diffraction grating or hologram becomes the light synthesis location 220. As a result, the predetermined light 230 is obtained. By manipulating / regulating in the above order along the light traveling direction 348 in the optical characteristic conversion block 390, the greatest effect can be exerted most efficiently.

[0215] Also, since the optical elements constituting inside the optical characteristic conversion block 390 shown in FIG. 17A are only the wavefront multi-division optical path length conversion element 360 and the diffusion plate 488 (or diffraction grating or hologram), there is an advantage that thinning and cost reduction are facilitated.

[0216] With the recent development of optical communication technologies, not only single-wavelength light typified by laser light but also all types of light including white light and full-color light are propagated and utilized via the optical fiber (waveguide) 330. The optical characteristic conversion block 390 shown in FIG. 17B shows a method of manipulating / regulating the optical characteristics of the predetermined light 230 in a form conforming to that technical trend. That is, the optical characteristic conversion block 390 of FIG. 17B is arranged in the middle of the optical propagation path 6 via the optical fiber (waveguide) 330.

[0217] The entrance of the optical characteristic conversion block 390 in FIG. 17B is connected to the input-side optical fiber 392, and the exit of the optical characteristic conversion block 390 is connected to the output-side optical fiber 398. The initial light 200 emitted from the input-side optical fiber 392 is converted into a substantially parallel light beam by the collimating lens 318. And in this far-field region 180, first along the light traveling direction 348, a substantially parallel light beam passes through the wavefront multi-division optical path length conversion element 360. And when passing through the wavefront multi-division optical path length conversion element 360, the phase synchronization characteristics are manipulated / regulated.

[0218] This wavefront multi-division optical path length conversion element 360 may be disposed in the vicinity region 170 close to the exit surface of the input-side optical fiber 392. However, considering a slight decrease in the amount of light at the boundary surface (for example, the side surface of the step in FIG. 7C) within this wavefront multi-division optical path length conversion element 360, it is desirable to dispose the wavefront multi-division optical path length conversion element 360 in the far region 180. Also, the shape of the wavefront multi-division optical path length conversion element 360 in FIG. 17B is a 48-division element already described in FIG. 7B. However, the specific shape of the wavefront multi-division optical path length conversion element 360 is not limited thereto, and a 12-division element described in FIG. 7C or a 2-division element disposed within FIG. 7A may also be used. When passing through the wavefront multi-division optical path length conversion element 360 along the light traveling direction 348, it is condensed by the condenser lens 314 toward the output-side optical fiber 398. A diffusion plate 488 is disposed immediately before the entrance of this output-side optical fiber 398. On the surface (the surface closest to the entrance of the output-side optical fiber 398) facing the entrance of the output-side optical fiber 398 within this diffusion plate 488, a first light diffusion region 489-1 and a second light diffusion region 489-2 are formed.

[0219] And the first light diffusion region 489-1 with a relatively small average value “Ra1” of the surface roughness and its average period “Pa1” constitutes the first region 212. Compared thereto, the second light diffusion region 489-2 with a relatively large average value “Ra2” of the surface roughness and its average period “Pa2” (satisfying the relationship of “Ra2 / Ra1 > 1” and “Pa2 / Pa1 > 1”) constitutes the second region 214.

[0220] In particular, similar to FIG. 16, with respect to the light that has passed through at least one region within the 48-division wavefront multi-division optical path length conversion element 360, a part of it necessarily passes through the first light diffusion region 489-1, and the remaining part passes through the second light diffusion region 489-2. By disposing the first light diffusion region 489-1 and the second light diffusion region 489-2 in this way, a great effect as described in Chapter 3 can be obtained.

[0221] The first light 202 that has passed through the first light diffusion region 489-1 individually and the second light 204 that has passed through the second light diffusion region 489-2 both propagate in the output-side optical fiber 398. And in the process of light propagation in this output-side optical fiber 398, the first light 202 and the second light 204 are combined. Therefore, the inside of this output-side optical fiber 398 functions as a light synthesis location 220. In this way, along the light propagation direction 348, sequential operation / control of the phase synchronization characteristic and operation / control of the phase characteristic (wavefront characteristic), light synthesis (that is, after passing through the optical path length conversion element 360 along the light propagation direction 348, passing through the light synthesis location 220 via the optical characteristic control element that performs operation / control of the phase characteristic (wavefront characteristic)), and the effects of Chapter 3 can be most effectively exerted.

[0222] Also, instead of the diffusion plate 488 in FIG. 17B, a diffraction grating or hologram having a fine concavo-convex structure on the surface may be arranged. Moreover, not limited thereto, instead of arranging the diffusion plate 488 in FIG. 17B, the entrance end face of the output-side optical fiber may be provided with a concavo-convex structure. In this case, within the entrance end face of the output-side optical fiber, a first region 212 and a second region 214 having different average values “Ra” of the surface roughness and its average period “Pa” from each other may be formed. Thus, when the entrance end face of the output-side optical fiber 298 is provided with a concavo-convex structure instead of arranging the diffusion plate 488 in FIG. 17B, the number of components of the optical element can be reduced. As a result, simplification, miniaturization, and cost reduction of the optical system can be achieved.

[0223] Chapter 6: Unique imaging spectrum measurement example combining imaging technology and spectroscopic characteristic measurement technology Regarding the measurement examples and service provision examples using the predetermined light 230 generated in the light source unit 2 or within the optical property conversion block 390 described up to the previous chapter, the following will be described. In the present embodiment, as already described in FIG. 1, the predetermined light 230 obtained within the light source unit 2 (in a broad sense including the light passing through the optical property conversion block 390) is transmitted via the optical transmission path 6, and this predetermined light 230 is irradiated onto the object 20 or measurement is performed by the measurement unit 4. Then, the information obtained as a result and each part 62 to 76 within the application field (various optical application fields) adaptation unit 60 are used in cooperation. As a result, service provision to the user is performed.

[0224] As an example of measurement and service provision using the predetermined light 230, a measurement method and service provision method using imaging spectrum, which combines imaging technology and spectroscopic property measurement technology, will be taken as an example and described below. However, it may be applied not only to imaging spectroscopic measurement but also to any measurement and service provision using the predetermined light 230 described up to the previous chapter.

[0225] FIG. 18A shows the spectroscopic properties of the absorbance obtained experimentally from glucose dissolved in pure water. The vertical axis in FIG. 18A shows the absorbance on a linear scale. For the measurement in FIG. 18A, the aforementioned predetermined light 230 was used. Most of the volume of the glucose aqueous solution is occupied by pure water. Therefore, most of the spectroscopic properties obtained from the glucose aqueous solution are composed of "the spectroscopic properties of pure water only". Therefore, the data of "the spectroscopic properties of pure water only" was measured in advance, and "the spectroscopic properties of pure water only" was subtracted from the spectroscopic properties obtained from the glucose aqueous solution to extract the spectroscopic properties of the absorbance of glucose alone dissolved in pure water.

[0226] In the measurement data of Fig. 18A(a), it shows that glucose dissolved in pure water has a large light absorption near a wavelength of 1.6 μm. This light absorption band is presumably due to the vibration mode of the hydrogen atom bonded alone to the carbon atom within the 5-membered ring that constitutes glucose. Also, although the light absorption amount is small, there seems to be a light absorption band corresponding to glucose near a wavelength of 1.24 μm shown in Fig. 18A(d).

[0227] Note that the measurement data in the wavelength ranges of Fig. 18A(b), (c), and (e) are interpreted as measurement errors. Glucose dissolves well in water. Generally, substances that dissolve well in water (soluble) often have local polarity. And when this polar substance dissolves in pure water, it is easy for a hydrogen bond chain in pure water to occur centered around this polar part. And when this hydrogen bond chain in pure water occurs, the maximum light absorption wavelength value in the "spectroscopic characteristics of pure water only" shifts to the long wavelength side. As a result, it is predicted that the absorbance changes in Fig. 18A(b) and (c) would appear.

[0228] To confirm the reliability of the measurement data in Fig. 18A, the absorbance characteristics of glucose alone (in the state before dissolving in water) were investigated through literature research. Fig. 18B shows the absorbance characteristics of glucose alone. Here, the vertical axis of Fig. 18B is shown in "absorbance" on a logarithmic scale. Although there is a difference in scale display, in both Fig. 18A and Fig. 18B, the light absorption amount is larger towards the upper side of the vertical axis. Note that Fig. 18B is Transcribed from "Near-Infrared Spectroscopy" (2005, The Society Publishing Center) edited by Yukihiro Ozaki and Akira Koda, P. 211 Even in Fig. 18B(b), absorption bands are observed at wavelengths of 1.6 μm and 1.26 μm. Therefore, from the comparison between Fig. 18A and Fig. 18B, the reliability of the measurement data in Fig. 18A could be confirmed.

[0229] Figures 19(a), 19(b), and 19(c) each show comparative measurement data of the relative absorbance of pure water, a polyethylene sheet, and a silk scarf. All of these data were measured using the predetermined light 230 described up to the previous chapter. There are significant differences in absorbance between pure water, the polyethylene sheet, and silk obtained from actual measurements. In Figure 19, corrections have been applied to the amount of change in absorbance for easier comparison.

[0230] Most of the living body is composed of water components, and in particular, the volume ratio of water in blood vessels is very large. The living body is mainly composed of the three major components "carbohydrates", "fats", and "proteins". Here, "carbohydrates" exist in the form of the aforementioned glucose relatives either alone (monosaccharides) or linked (polysaccharides). Also, the atomic arrangements in many "fats" are structurally similar to polyethylene. Furthermore, silk is made from "proteins". Therefore, generally speaking, the absorption characteristics of the four major components that make up the living body including water are considered to show absorption characteristics close to either Figure 18A or Figure 19.

[0231] Figure 20A shows an example of a measurement environment using imaging spectroscopy. The predetermined light 230 described up to the previous chapter is emitted from the light source unit 2. Then, the predetermined light 230 emitted from the light source unit 2 is reflected by the palm 23 in the measurement object 22 and enters the measurement unit 8. And Figure 20B shows an example of an image captured in the measurement unit 8. As shown in Figure 20B, a blood vessel region 500 exists at a predetermined position inside the palm 23.

[0232] Figure 20C shows an example of an enlarged image around the blood vessel region 500. In this embodiment, the spectral characteristics of each pixel in an image arranged one-dimensionally are measured. At the same time, the connected region of pixels for which spectral characteristic measurement is possible is called the simultaneous measurement possible range 510.

[0233] From the fatty area 504 within the simultaneous measurement range 510 of FIG. 20C, the spectral characteristics (absorbance characteristics) shown in FIG. 20C(b) can be obtained. Also, from the blood vessel area 500 and the muscle-rich area 502 within the simultaneous measurement range 510, the spectral characteristics (absorbance characteristics) shown in FIGS. 20C(a) and 20C(c) can be obtained. Therefore, the arrangement information of, for example, the blood vessel area 500 can be predicted from the spectral characteristics (absorbance characteristics) obtained for each pixel within the simultaneous measurement range 510.

[0234] As shown in FIG. 20D with respect to FIG. 20C, when multiple simultaneous measurement ranges 510-1 and -2 can be used simultaneously at multiple locations and the number of pixels for which spectral characteristics can be measured increases, as a result, the number of pixels of imaging spectroscopy that can be measured at one time increases dramatically. Furthermore, if the simultaneous measurement ranges 510-1 and -2 can be simultaneously moved 520, the spectral characteristics for all pixels in two dimensions can be collected in a very short time. That is, just by moving the position of the simultaneous measurement range 510-1 by the simultaneous movement 520 to the position of the simultaneous measurement range 510-2 before the simultaneous movement 520, the spectral characteristics for all pixels can be collected in a short time. To enable this measurement, in this embodiment, the optical property conversion element 210 already described with reference to FIG. 5A is arranged within the measurement unit 4. Note that the spectral characteristic information for all pixels in two dimensions is called a data cube. In the explanation using up to FIG. 20D, the spectral characteristic information (data cube) for all pixels in two dimensions can be measured.

[0235] FIGS. 20E and 20F show a method for obtaining spectral characteristic information for each three-dimensional pixel including the depth direction (z-axis direction). As shown in FIG. 20E, by arranging two sets of the measurement optical systems described in FIG. 5A and using the convergence angle between the two-dimensional images detected between them, it becomes possible to collect a data cube that depends on the distance "Z0" in the depth direction. Here, if the interval between the two slits 350-1 and 350-2 is controlled (changed) or the interval between the two imaging lenses 310-1 and 310-2 is controlled (changed), the convergence angle changes. As a result, the position "Z0" in the measured front-back (depth or depth) direction changes.

[0236] Figure 20F shows a method of improving the resolution in the front-rear (depth or depthwise) direction by controlling (changing) the intervals between the imaging lenses 310-1 and 310-2 and the slits 350-1 and 350-2. Further, narrowing the slit width (the width of the region through which the detection light passes) within the slits 350-1 and 350-2 further improves the resolution in the front-rear (depth or depthwise) direction.

[0237] That is, FIG. 20E shows a case where a data cube can be collected from an optimal measurement position within the measurement object 24. In comparison, the detection light from FIGS. 20F(a) and 20F(b) protrudes from the slit widths within the slits 350-1 and 350-2. And since it is blocked by the slits 350-1 and 350-2, the detection light from FIGS. 20F(a) and 20F(b) does not reach the imaging elements 300-1 and -2. For this reason, the resolution in the front-rear (depth or depthwise) direction is improved.

[0238] Chapter 7 Examples within the Detection Unit In FIG. 5A, the operating principle of the optical property conversion element 210 was mainly described. This time, with reference to FIGS. 21A and 21B, a method of performing imaging spectroscopic measurement accurately and at high speed will be described.

[0239] FIG. 21A shows a cross-sectional view (XZ cross-sectional view) in the plane direction including the X-axis on the slit 350 (optical property conversion element 210). The predetermined light 230 traveling along the "XZ plane" on the slit 350 (optical property conversion element 210) moves in the "Xd" direction on the imaging element 300. Further, FIG. 21B shows a cross-sectional view (YZ cross-sectional view) in the plane direction including the Y-axis on the slit 350 (optical property conversion element 210). And each different point "σ", "ξ" on the slit 350 along the Y-axis is imaged on each different point "ν", "μ" along the Yd direction on the imaging element 300.

[0240] The imaging image for the location to be measured spectroscopically in the measurement object 22 of FIG. 20A (for example, in the vicinity of the blood vessel region 500 in the palm 23) is formed on the slit 350 (optical property conversion element 210) of FIGS. 21A and 21B. Then, only the imaging image region corresponding to the simultaneously measurable range 510 (FIGS. 20C and 20D) in the measurement object 22 passes through the light transmission regions “α” and “β” in the slit.

[0241] The predetermined light 230 that has passed through the α region of FIG. 21A is converted into a parallel light beam “α0” by the collimating lens 318 and then spectroscopically analyzed on the surface of the spectroscopic element (blazed grating) 320. For the sake of simplicity of explanation, consider the case where among the light reflected from the surface of the spectroscopic element (blazed grating) 320, the long-wavelength light travels in the “α2” direction as parallel light and the short-wavelength light travels in the “α1” direction as parallel light. Then, this parallel light is focused on the surface of the imaging element 300 after passing through the condenser lens 314. At this time, the short-wavelength light traveling in the “α1” direction is focused on the “γ point” within the spectroscopic property detection region 302 of the light passing through the α region. On the other hand, the long-wavelength light traveling in the “α2” direction is focused on the “δ point” within the spectroscopic property detection region 302 of the light passing through the α region. In this way, for each wavelength after spectroscopic analysis, it is focused at different positions in the “Xd” direction within the spectroscopic property detection region 302 of the light passing through the α region. Therefore, by measuring the detection intensity distribution along the “Xd” direction within the spectroscopic property detection region 302 of the light passing through the α region, the spectroscopic property of the predetermined light 230 that has passed through the α region can be measured.

[0242] Next, the predetermined light 230 that has passed through the β region in FIG. 21A is converted into a parallel light beam “β0” by the collimating lens 318 and then split on the surface of the spectroscopic element (blazed grating) 320. Among the light reflected from the surface of the spectroscopic element (blazed grating) 320, the long-wavelength light proceeds in the “β2” direction as parallel light, and the short-wavelength light proceeds in the “β1” direction as parallel light. Then, this parallel light is focused on the surface of the imaging element 300 after passing through the condenser lens 314. At this time, the short-wavelength light that has proceeded in the “β1” direction is focused on the “ε point” within the spectroscopic characteristic detection region 304 of the light passing through the β region. On the other hand, the long-wavelength light that has proceeded in the “β2” direction is focused on the “ζ point” within the spectroscopic characteristic detection region 304 of the light passing through the β region. In this way, for each wavelength split, it is focused at different positions in the “Xd” direction within the spectroscopic characteristic detection region 304 of the light passing through the β region. Therefore, by measuring the detection intensity distribution along the “Xd” direction within the spectroscopic characteristic detection region 304 of the light passing through the β region, the spectroscopic characteristics of the predetermined light 230 that has passed through the β region can be measured.

[0243] As a method of simultaneously moving the plurality of simultaneously measurable ranges 510-1, -2 as described in FIG. 20D, the moving mechanism 444 of the imaging lens 310 in FIG. 21A or the moving mechanism 444 of the slit 350 (optical characteristic conversion element 210) is operated to move the imaging lens 310 or the slit 350 (optical characteristic conversion element 210). When only the imaging lens 310 is moved, the position of the slit 350 (optical characteristic conversion element 210) is fixed. Therefore, the positions of the spectroscopic characteristic detection region 302 of the light passing through the α region and the spectroscopic characteristic detection region 304 of the light passing through the β region within the imaging element 300 are fixed. Since signal processing can be simplified, when used in an application field where slow collection of a data cube is allowed, it is desirable to fix the position of the slit 350 (optical characteristic conversion element 210) and move only the imaging lens 310.

[0244] The weight (mass) of the imaging lens 310 is overwhelmingly larger than the weight (mass) of the slit 350 (optical characteristic conversion element 210). Therefore, when used in an application field where it is desired to simultaneously move the simultaneous measurement possible ranges 510-1 and -2 at high speed, it is desirable to fix the position of the imaging lens 310 and move only the slit 350 (optical characteristic conversion element 210). In this case, as the slit 350 (optical characteristic conversion element 210) moves, the positions of the spectroscopic characteristic detection region 302 for the light passing through the α region and the spectroscopic characteristic detection region 304 for the light passing through the β region in the imaging element 300 are displaced. Therefore, when responding at high speed, it is necessary to correct the corresponding detected wavelength values for each pixel on the imaging element 300 while monitoring the moving position of the slit 350 (optical characteristic conversion element 210) by some method. Thus, in the "Xd direction" on the imaging element 300, information on the spectroscopic characteristics for each of the light transmission regions "α" and "β" of the slit 350 (optical characteristic conversion element 210) can be obtained.

[0245] In the "YZ cross-sectional" direction shown in FIG. 21B, the spectroscopic element 320 functions as a simple plane mirror. Therefore, the imaging image with respect to the image on the slit 350 (optical characteristic conversion element 210) appears as it is in the "Yd direction" on the imaging element 300. That is, the predetermined light 230 emitted from the "σ point" on the slit 350 (optical characteristic conversion element 210) is condensed at the "μ point" on the imaging element 300. Also, the predetermined light 230 emitted from the "ξ point" on the slit 350 (optical characteristic conversion element 210) is condensed at the "ν point" on the imaging element 300. Thus, in the imaging spectroscopy in this embodiment, the imaging image appears in the "Yd direction" on the imaging element 300, and the spectroscopic characteristics appear in the "Xd direction" on the imaging element 300.

[0246] Chapter 8 Service Provision System (Hierarchical Structure of the Platform) In the service providing system 14 of FIG. 1, the data cube extracted by the measurement unit 8 is sent to the application field (various optical application fields) adaptation unit 60 via the in-system control unit 50. And FIG. 22A shows the hierarchical structure of the platform controlled within the application field (various optical application fields) adaptation unit 60. Each block in FIG. 22A may be composed of hardware. Also, without being limited thereto, software modules may be formed for each block. When such software modules are formed, they may receive command control via an API (application interface) from the upper layer.

[0247] An integrated management control block 602 is arranged in the topmost service integration layer 600, where overall control including service provision to the user is performed. In the execution control layer 610 for various processes below it, a data cube collection control block 612, a collected data management block 614, a billing / maintenance control block 616, and various service provision blocks 618 are installed.

[0248] From this data cube collection control block 612, the depth direction measurement control unit 622, the control block 620 of the measurement unit, the data recording unit 626, the recording unit 628 of the time-varying data cube, and the data processing block 630 can be individually controlled. Also, from this control block 620 of the measurement unit, the temperature (far-infrared light) measurement control unit (thermography) 660, the visible light measurement control unit 650, and the near-infrared light measurement control unit 640 can be integrally controlled individually.

[0249] And in the near-infrared light measurement control unit 640, the dark current measurement control unit 642, the reference signal measurement control unit 646, and the measurement signal measurement control unit 648 are properly operated to collect a highly accurate data cube.

[0250] FIG. 22B shows the control system structure within the data processing block 630 described in FIG. 22A. That is, within the data processing block 630, there are set up an in-screen area identification / separation processing unit 670, a predetermined signal (spectrum) extraction unit 680, a time-varying component extraction processing unit 700, a summation processing unit 710 for each signal extracted for each common predetermined area, and a quantification prediction processing unit (absorbance correction) 720 for each component.

[0251] Then, the in-screen area identification / separation processing unit 670 operates an individual identification processing unit (using visible light image) 672, an intra-individual identification processing unit (using near-infrared light image) 676, and an intra-individual predetermined area extraction unit 678 installed at the lower part to extract the site where the spectral characteristics are to be measured.

[0252] When the site where the spectral characteristics are to be measured is extracted in this way, the predetermined signal (spectrum) extraction unit 680 operates a comparison signal (spectrum) generation unit 682 installed at the lower part and a subtraction processing unit 684 for the comparison signal from the measurement signal to measure highly accurate spectral characteristic information regarding the component to be measured. Here, within the comparison signal (spectrum) generation unit 682, an intra-individual predetermined area temperature prediction unit 692, a temperature correction processing unit 696 for the comparison signal, and a comparison signal database 698 installed at the lower level are operated to correct the measurement results.

[0253] FIG. 23 shows a series of processing procedures from the extraction of the data cube to data processing and service provision to the user by utilizing the platform described in FIG. 22A. For the sake of convenience of explanation, the processing procedures will be described by taking "the method for automatically collecting blood glucose values" as an example. However, it is not limited thereto, and the procedures described in FIG. 23 can be applied to a wide range of processing procedures.

[0254] When the data collection / analysis / service provision shown in step 1 is started, first, the collection (SZT2) of the data cube signal at the measurement unit 8 is performed. All the data cube signals collected here are temporarily stored in the collection data management block 614, and the data processing described later is executed.

[0255] As the first stage of data processing, extract the part that is particularly desired to be measured from all the collected data cubes. First, in step 3 of the individual identification process (using visible light images), the individual identification processing unit (using visible light images) 672 extracts only the person area within all the data cubes by using the information of the visible light image obtained from the visible light measurement control unit 650. Next, in the in-individual identification process (ST4) using the near-infrared light image, the in-individual identification processing unit (using the near-infrared light image) 676 performs the identification process for each area. Specifically, as shown in FIG. 20C, area identification such as the blood vessel area 500, the area 504 with a lot of fat, and the area 502 with a lot of muscle is performed by using the near-infrared spectroscopic characteristics. After that, the in-individual predetermined area extraction unit 678 performs the in-individual predetermined area extraction (ST5).

[0256] Since the living body contains many components and has a complex structure, high measurement accuracy cannot be obtained by simply analyzing the spectroscopic characteristics at a predetermined extraction location within the individual. Therefore, the following data processing operations are performed to obtain high measurement accuracy. For example, when measuring blood glucose levels, it is necessary to remove unnecessary water components from the spectroscopic characteristics obtained from the blood vessel region 500 and extract only the spectroscopic characteristics of the glucose component contained in the blood. Here, even if an attempt is made to remove the signal component from water within the blood vessel region 500, the spectroscopic characteristics of water vary greatly with temperature. As a result, error signals shown in FIGS. 18A(b) and 18A(c) are mixed in. Therefore, in this embodiment, temperature correction regarding the spectroscopic characteristics of water is performed within the temperature correction processing unit 696 for the comparison signal. Specifically, the temperature prediction unit 692 for a predetermined region within the solid controls the temperature (far-infrared light) measurement control unit 660 using thermography to measure the blood vessel temperature. Next, the temperature correction processing unit 696 for the comparison signal utilizes the measured blood vessel temperature result, reads the spectroscopic characteristic information of water for each measured temperature pre-recorded in the comparison signal database 698, and determines the spectroscopic characteristics of water corresponding to the measured blood vessel temperature. Then, within the comparison signal (spectrum) generation unit 682, spectroscopic characteristic information of water corresponding to the determined blood vessel temperature is generated. And within the subtraction processing unit 684 for the comparison signal (spectrum) from the measurement signal, the water spectral component is subtracted from the spectroscopic characteristic information obtained from the blood vessel region 500 to extract the spectroscopic characteristics of glucose. This series of processes corresponds to the step (ST6) of extracting a predetermined signal (spectrum).

[0257] Since cholesterol exists inside the blood vessels, it is necessary to separate the glucose component in the blood vessels from the cholesterol component. There is pulsation in the blood flow, and the detected signal amount of the glucose component in the blood vessels changes accordingly. Therefore, in the time-varying component extraction process (ST7), the time-varying pulsation component is extracted within the time-varying component extraction unit 700, and signal separation from cholesterol inside the blood vessels is performed.

[0258] Furthermore, to improve the measurement accuracy, in the step ST8 of adding up the extracted signals, within the adding-up processing unit 710 for the signals extracted for each common predetermined region, for example, the signals obtained from all the blood vessel regions 500 are added up.

[0259] In near-infrared spectroscopy, the light absorption efficiency varies for each absorption band to be measured. Therefore, simply calculating the absorbance of the absorption band does not allow, for example, the absolute amount of glucose to be known. For this reason, in step ST9 of the quantification prediction process for each component, absorbance correction is performed inside the quantification prediction unit 720 for each component, and the absolute value of the content for each component is predicted.

[0260] In step ST11 of service provision, service is provided to the user based on the data processing result. For example, when a diabetes risk is detected from the blood glucose measurement result, the user and the attending physician may be notified using email. Not limited to such notification, service may be provided to the user by other appropriate methods. And when the appropriate service provision is completed, data collection / analysis / service provision is terminated (ST12).

[0261] In step ST11 of the above service provision, each application field adaptation unit 60 in the service provision system 14 is individually operated. In particular, in the service provision in this embodiment, information transmission with the external system 16 via the information transmission path 4 may be used.

[0262] For example, a light source unit 2 disposed remotely from the measurement object 22 may irradiate short-term pulsed light, and the time until the pulsed light returns to the measurement unit 8 may be measured to measure the distance to the measurement object 22 (length measurement). The time width of the pulsed light at this time is preferably in the range of 0.1 nS to 100 μS.

[0263] Also, when a light-detectable aggregate (such as a p-i-n photodiode array) two-dimensionally arranged in a monolithic or hybrid form is configured in the measurement unit 8, three-dimensional image collection becomes possible. In this case, the signal processing unit 42 determines the time until the pulsed light reaches each light detection cell. Then, the characteristic analysis / analysis processing unit 62 receives the time information until the pulsed light reaches each light detection cell transmitted from the signal processing unit 42 via the system internal control unit 50, and generates three-dimensional image information for the measurement object 22.

[0264] As another example, when providing services related to telemedicine, the medical / welfare-related examination processing unit 70 operates, and the information obtained from the quantification prediction processing unit 720 for each of the above components can be used to assist in remote diagnosis. Specifically, the blood glucose level predicted by the method described above can be used for the diagnosis of diabetes. Also, from the pulsation waveform obtained simultaneously at this time, it may be used for the diagnosis of arrhythmia related to heart disease.

[0265] For example, a processing example when an arrhythmia is detected in the pulsation waveform during the measurement of the blood glucose level of a specific user will be described. The pulsation waveform of the specific user 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 in-system control unit 50. Then, this characteristic analysis / analysis processing unit 62 analyzes the pulsation waveform and performs pattern matching with the standard waveform and the diseased waveform. As a result, it is possible to detect an arrhythmia and predict a defective part in the heart. And the arrhythmia detection result and the defect prediction information in the heart part are transmitted to the medical / welfare-related examination processing unit 70 via the in-system control unit 50.

[0266] Next, the medical / welfare-related examination processing unit 70 provides information (for example, email transmission) to the attending doctor in the external system 16 via the information transmission path 4. Also, if this specific user has a prior contract with a predetermined insurance company (casualty insurance company), the medical / welfare-related examination processing unit 70 automatically provides information (for example, email transmission) to the above insurance company (casualty insurance company). As a result, it is possible to provide a service that substitutes for troublesome procedures such as hospital admission arrangements and reduction of treatment costs without imposing a burden on the user.

[0267] Also, when a patient is recuperating from illness or during the treatment of a specific illness, the treatment suitability control / processing unit 68 operates, and a doctor may remotely monitor the progress of the treatment. That is, by tracking the temporal changes in the blood glucose level and the pulsation waveform, a doctor far away can understand the progression of the illness and the course of recovery.

[0268] Not limited to the above, the health information of the user may also be used for any other service provision. For example, when concluding a contract for casualty insurance such as automobile insurance or unemployment insurance, the casualty insurance company may use the optical utilization device 10 to examine the health status of the user who is the subject of the contract. And a service may be provided to set the amount of damage compensation based on the information obtained from the optical utilization device 10.

[0269] Not limited to that, for example, when a user deposits money in a bank or when setting the interest rate and financing conditions for financing from the bank to a company (operated by the user), the information obtained from the optical utilization device 10 may be used.

[0270] As another example of service provision forms, the information obtained from the optical utilization device 10 may be used in the educational field. For example, from the pulse rate, respiratory rate, eye movement, and eyelid movement, it is possible to predict the concentration and drowsiness of the students. From the concentration and drowsiness information of the students obtained from the optical utilization device 10, the lecture content can be appropriately changed. Thereby, the educational efficiency is improved.

[0271] Also, as an application example of service provision forms, it is also possible to apply it to abnormal monitoring in public facilities. When a person is in a "nervous state" or "excited state", the pulse (pulse rate) tends to increase. And a terrorist just before an incident is in a "nervous state" or "excited state" inside, and in many cases, the face is tense due to nervousness. Therefore, if a surveillance camera is remotely operated to simultaneously measure the pulse rates of an unspecified number of people, it is possible to extract a person whose pulse rate is abnormally high and whose facial expression muscles are contracted.

[0272] In this embodiment, using the information transmission path 4, the optical utilization device 10 may serve as an entrance to the cyber space. (That is, via the information transmission path 4, the optical utilization device 10 can be directly connected to the cyber space.) As an example of service provision corresponding to the role of this entrance to the cyber space, personal authentication when entering the cyber space, search and guidance for the most suitable place for each user after entering the cyber space, substitution of the active actions of the user in the cyber space, and all services in the cyber space such as security protection may be provided.

[0273] In this embodiment, it is possible to automatically input and identify and determine a blood vessel pattern or fundus pattern at any part of the user's body using the light utilization device 10 (or the service providing system 14 therein), or perform face authentication or body shape authentication using the visible light camera built into the measurement unit 8. Therefore, in this embodiment, it is possible to provide a personal authentication service when entering the cyber space by using the user-related information collected by the light utilization device 10. Further, a personal authentication service may be provided using any method other than the above (for example, voiceprint detection).

[0274] As an example of the physical form of the light utilization device 10 as an entrance to this cyber space, FIG. 20A shows a form of installation at a fixed position. However, without being limited thereto, as another physical form of the measurement unit, the camera unit of a personal computer or a portable terminal (such as a smartphone or a tablet) may be used.

[0275] Furthermore, as the physical form of the display unit 18 in the light utilization device 10, a wearable terminal that can be worn by the user may be used. This wearable terminal that can be worn by the user may take any physical form such as glasses shape, hat shape, helmet shape, bag shape, etc.

[0276] For example, in the case of a glasses shape or a type that the user directly wears to realize VR (Virtual Reality) or AR (Augmented Reality), there is a place that directly contacts the user's skin. At least a part of the measurement unit 8 in the above light utilization device may be arranged in the area that directly contacts the user's skin.

[0277] When measuring the content of specific components such as noradrenaline in the blood through blood analysis, the psychological state of the user wearing the terminal, such as "nervous state" or "excited state", can be estimated. In addition, the psychological state of the user can also be estimated from the contraction locations of the facial muscles present on the user's face. Furthermore, as described above, it is also possible to extract the person being measured who is in a "nervous state" or "excited state" from the pulse rate of the person shown in a remote camera or the like. Moreover, not limited thereto, in this embodiment, the activities of individual nerve cells (neurons) within the user's head can be monitored. Therefore, by using the light utilization device 10, an efficient approach from the user to the cyber space becomes possible.

[0278] As a method for the user to actively act on the cyber space with the conventional technology, for example, vocalization or finger operations such as keying in were required. Therefore, a great deal of time was spent on the approach to the cyber space using the conventional technology. In contrast, in this embodiment, the psychological state and will of the user can be predicted automatically and at high speed within the light utilization device 10, and a prompt and appropriate response can be made to the cyber space. Therefore, in this embodiment, without requiring troublesome operations such as vocalization or finger movements for the user, it is possible to provide information 72 desired by the user at high speed and to respond to the cyber space.

[0279] Moreover, not limited thereto, by using various non-optical sensors 52 within the light utilization device 10, high user convenience regarding the response to the cyber space can be provided. For example, as various non-optical sensors 52, a gyroscope and an acceleration sensor are arranged, and the case of detecting the movement of the user's head or a part of the user's body (such as a hand or a finger) will be described as an example. When the user shakes their head while an image (video) is being displayed on the display unit 18 using a glasses-type wearable terminal such as VR or AR, the display screen rotates accordingly. When the user leans forward or sways backward, they move forward or descend backward on the display screen. Here, for example, when attempting to move at high speed within the cyber space in a game or the like, a limit occurs in the response speed of the above gyroscope and acceleration sensor. In this case, by predicting the psychological state and will of the user and making a prompt and appropriate response to the cyber space, the convenience of the user within the cyber space is significantly improved.

[0280] An example of service provision to a user in cooperation among the information provision unit 72, the collected information storage 74, and the signal processing unit 42 within the service provision system 14 is shown below. For example, consider an example of a service provision for displaying a menu screen on a VR screen or an AR screen of a wearable terminal (such as glasses or a helmet) worn by the user. If the "liking degree" (or the degree of discomfort) of the user is estimated by the light utilization device 10 simultaneously with the detection of the user's line of sight, a screen preferred by the user can be displayed instantaneously (in a short time).

[0281] Also, for example 1. A wearable terminal such as VR or AR is incorporated into the display unit 18, 2. A gyroscope or an acceleration sensor in the various non-optical sensors 52 detects the movement of the user's head or finger (or hand), 3. Using the biological signal of the user measured by the measurement unit 8, the signal processing unit 42 outputs information regarding the user's organism, 4. When the in-system control unit 50 integrates and uses the above information, An identity within the cyber space corresponding to the user using the light utilization device 10 is formed. And any service for this identity within the cyber space can be provided. Moreover, not limited to that, it becomes possible to operate a robot arranged on the real space via the cyber space to provide further services to the user.

[0282] For example, by operating an automatically walkable robot installed in a remote location, a tourism service for the user can be provided. Also, by operating an automatically walkable robot installed in a hospital or a facility, a care service from a distance etc. can be provided. In the prior art, voice input or the movement of the user's finger (or hand) was required for the above identity operation within the cyber space or the robot operation on the real space. When using the light utilization device in this embodiment, troublesome vocalization and finger movement become unnecessary, and high-speed operation becomes possible. Thereby, the convenience of service provision in this embodiment is greatly improved.

[0283] As another embodiment of service provision using the cyber space, it may be used for marketing applications. For example, while displaying predetermined images or videos on a VR screen or an AR screen via the information providing unit 72, the emotions and wills of the user may be estimated one by one within the light utilization device 10. Then, when the user shows a favorable impression or interest, the images, videos, and sounds to be displayed are appropriately stored in the collected information storage unit 74. The external system 16 collects the information (images, videos, sounds) stored in the collected information storage unit 74 via the information transmission path 4 at an appropriate timing. Next, the information collected within the external system 16 is analyzed to extract products with purchasing power, and the information may be provided to the sales company of the corresponding products for a fee.

[0284] In the service provision on the cyber space in this embodiment, personal information management is very important. Therefore, among the service provisions in this embodiment, the personal information management service itself becomes a very important service. When a specific user enters the cyber space and then conducts activities within the cyber space, an account ID (identification) for identifying each user is used. When the health information and preference information of the user obtained from the light utilization device 10 are associated with the above account ID, it leads to personal information.

[0285] As an example of service provision in this embodiment, a personal information management agent may be resident in the collected information storage unit 74 or in 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 (nerve impulse)" is analyzed within the signal processing unit 42. Then, advanced judgments such as "estimation of user emotions", "estimation of user preferences", and "estimation of user will" using the information are made within the characteristic analysis / analysis processing unit 62. And the information obtained by this characteristic analysis / analysis processing unit 62 is appropriately stored in the collected information storage unit 74. And 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.

[0286] In the service provision example in this embodiment, the personal information management agent links the external scope information that can be transmitted for each piece of information obtained by the characteristic analysis / analysis processing unit 62. Therefore, for all the information stored in the collected information storage unit 74, the external scope information that can be transmitted is set. And for each information transmission request from the external system 16, the personal information management agent determines whether it can be transmitted externally. By performing the personal information management service in the optical utilization device 10 in this way, highly reliable personal information protection becomes possible.

[0287] As another service provision application example in this embodiment, it may be used as a tool for creating (training) artificial intelligence. As the artificial intelligence here, for example, the "parallel processing method with a multi-input and multi-output learning function" used in deep learning technology or quantum computer technology may be used.

[0288] As a complex analysis / processing example suitable for multi-input and multi-output parallel processing, for example, image analysis, image understanding, or language processing, language understanding, advanced judgment adapted to complex situations, etc. can be cited. Both the human and the artificial intelligence of the measurement object 22 are given these tasks at the same time. And using the answer given by the human as the correct answer, learning feedback may be applied to the artificial intelligence so as to approach the correct answer.

[0289] These tools may be executed in the cyber space. In this case, the artificial intelligence to be learned is pre-installed on the external system 16, and the correct answer given by the human can be notified to the artificial intelligence from the optical utilization device 10 (or the application field adaptation unit 60) via the information transmission path 4.

[0290] The service provision example is not limited to the above. Any service provision may be performed in a form in which the optical utilization device 10 is connected to the cyber space constructed on the external system 16 via the information transmission path 4.

[0291] Chapter 9 Application Devices FIG. 24 shows an application example of the present embodiment. For example, an optical propagation path 6 from the light source unit 2 toward the measurement unit 8 may be installed in the path of the substance separated by liquid chromatography on the way to the mass spectrometry unit, and component analysis of the substance separated by liquid chromatography may be performed.

[0292] FIG. 25 shows a method of simultaneous parallel analysis using imaging spectroscopy for each component two-dimensionally separated by two-dimensional electrophoresis. A positive electrode 912 and a negative electrode 918 are arranged in a two-dimensional electrophoresis analysis container 900. In the two-dimensional electrophoresis analysis container 900, the SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) direction 930 is defined along the gel concentration gradient direction 922 of the gradient gel 920. Also, an isoelectric focusing electrophoresis direction 940 is set in a direction perpendicular to it.

[0293] A light source unit 2 is installed at the rear part of the two-dimensional electrophoresis analysis container 900. The predetermined light 230 emitted from this light source unit 2 passes through the inside of the two-dimensional electrophoresis analysis container 900 and reaches the measurement unit 8 arranged in front. The inside of this measurement unit 8 has the optical structure already described with reference to FIGS. 5A, 21A, and 21B.

[0294] For example, a voice coil or the like is built into a moving mechanism 444 connected via a slit 350 and a connecting portion 950, and a current is passed through this voice coil to move the slit 350. As already described with reference to FIGS. 20E and 20F, the distance between the imaging lens 310 and the slit 350 needs to be maintained with high accuracy. Therefore, for example, when the imaging lens 310 is fixed, a device is required such that the distance between the imaging lens 310 and the slit 350 does not change when the slit 350 moves. Therefore, a slit sliding / sensor unit 960 that slides on a part of the slit 350 is installed.

[0295] Inside this slit sliding / sensor unit 960, a rotating column 966 that rotates and slides with respect to a part of the slit 350 and a rotating column support portion 964 that fixes it are provided. And due to the action of the pressing spring 968 of the rotating column support portion, this rotating column support portion 964 is pressurized in the direction of the slit 350. By providing a mechanism that rotates and slides with respect to a part of the slit 350 in this way, not only is the distance from the imaging lens 310 kept constant even when the slit 350 moves, but also the high-speed movement of the slit 350 is facilitated.

[0296] Also, inside the slit sliding / sensor unit 960, a slit position detection light source 972 and an optical slit position detector 978 are arranged, and it is possible to accurately detect the slit position by optical means. And feedback 962 of the slit position is performed with the detection signal here, and conversion of the corresponding measurement wavelength value for each pixel in the "Xd" direction in the imaging element 300 is performed.

[0297] Chapter 10 High-Precision Measurement Method in the Field of Optical Applications FIG. 26A shows the high-precision measurement method in this embodiment example in the field of optical applications. This FIG. 26A is drawn by extracting and showing the main part inside the optical utilization device 10 described in FIG. 1. That is, optical measurement 1002 on the measurement object 24 is performed in the measurement unit 8. And for the result of the optical measurement 1002 obtained there, analysis is performed in the signal processing unit 42 to perform necessary information extraction 1004.

[0298] Here, in order to perform high-precision information extraction 1004, it is necessary to minimize disturbance noise in both the processes of optical measurement 1002 and information extraction 1004. When measuring in the optical application field 100 using the optical utilization device 10, two types of disturbance noises, optical noise and electrical noise, are likely to be mixed in. Therefore, in order to perform high-precision measurement, it is desirable to reduce two types of disturbance noises, optical disturbance noise reduction and electrical disturbance noise reduction 1012.

[0299] In particular, in this embodiment, highly accurate information extraction 1004 is performed using an optical system capable of reducing optical noise. As a method for reducing optical disturbance noise in a conventional optical utilization device 10 used in the optical application field 100, only consideration of about stray light mixing αc1 was performed. However, actually, large optical disturbance noise is generated from optical interference αc2 that occurs during the optical propagation path 6. Therefore, in the prior art, there has been a problem that it is difficult to fully exhibit the effect of electrical disturbance noise reduction processing. And when large optical disturbance noise caused by optical interference αc2 occurs, the good function performance in all optical application fields 100 shown in FIG. 2 has been inhibited.

[0300] Therefore, the optical utilization device 10 in this embodiment uses an optical system that reduces optical disturbance noise derived from optical interference αc2. And after reducing the influence of optical interference αc2 that occurs during the optical propagation path 6, reduction processing of optical disturbance noise or electrical disturbance noise reduction processing 1012 generated by other factors may be performed. Alternatively, the optical utilization device 10 in this embodiment may have an optical system that reduces optical disturbance noise derived from optical interference αc2, and may also use a combination of reduction of optical disturbance noise and reduction of electrical disturbance noise 1012 generated by other factors.

[0301] The optical system that reduces optical disturbance noise derived from optical interference αc2 in this embodiment example intensity-adds lights 202 and 204 that have passed through regions 212 and 214 with different optical path lengths from each other. Based on this, different noise patterns (noise characteristics) that are individually generated in the individual lights 202 and 204 are averaged (smoothed), and as a result, optical disturbance noise derived from optical interference αc2 is reduced. This optical system that reduces optical disturbance noise derived from optical interference αc2 may be arranged at any position within the optical utilization device 10. That is, it may be arranged in an optical system (for example, within the light source unit 2) before irradiating the measurement object 22 with light. Alternatively, it may be arranged in an optical system (for example, within the measurement unit 8) through which the detection light obtained from the measurement object 22 passes.

[0302] In this way, while reducing the influence of the optical interference αc2 generated during the optical propagation path 6, by performing the reduction process of the optical disturbance noise or the electrical disturbance noise 1012 generated by other factors, the reduction of the optical disturbance noise or the electrical disturbance noise 1012 can be effectively performed.

[0303] Furthermore, in the embodiment shown in FIG. 26A, by utilizing the information obtained from the detection light, the reduction of the optical disturbance noise or the electrical disturbance noise 1012 is performed. Specifically, first, the predetermined light is irradiated onto the measurement object, and the first information is acquired from the predetermined light or the detection light obtained from the measurement object. Next, using the first information, the reduction of the optical disturbance noise or the electrical disturbance noise 1012 is performed on the signal obtained from the detection light. Then, the second information is acquired from the signal after the reduction of the optical disturbance noise or the electrical disturbance noise 1012 is performed.

[0304] That is, the predetermined light emitted from the light source unit 2 is irradiated onto the measurement object 22. As the wavelength of this predetermined light, visible light of 400 nm or more and 700 nm or less may be used. Moreover, not limited thereto, near-infrared light of 700 nm or more and 2.5 μm or less, infrared light of 2.5 μm or more and 20 μm or less, or far-infrared light having a longer wavelength than that may be used. Here, as the light emitting unit 470 in the light source unit 2, various lamps such as a halogen lamp, a mercury lamp, and a xenon lamp, or an incandescent light emitter may be used. Moreover, not limited thereto, an LD (Laser Diode) or an LED (Light Emitting Diode) may be used as the light emitting unit 470.

[0305] Then, the detection light obtained from the measurement object 22 is detected by the measurement unit 8. Here, the transmitted light from the measurement object 22 may be used as the detection light, or the reflected light from the measurement object 22 may be used as the detection light. Moreover, not limited thereto, the scattered light from the measurement object 22 may be used as the detection light.

[0306] When using light of the same wavelength as the predetermined light as the wavelength light used as the detection light, it becomes possible to measure the light absorption characteristics (absorbance described later) for each wavelength light within the measurement object 22. On the other hand, when using light of a wavelength longer than the wavelength of the predetermined light as the detection light, it becomes possible to measure Raman scattering characteristics, fluorescence characteristics, and phosphorescence characteristics within the measurement object 22.

[0307] Next, the signal from the detection light obtained by the measurement unit 8 is signal-processed within the signal processing unit 42 to obtain first information. Then, using this first information, a disturbance noise reduction operation is performed within the signal processing unit 42. As a result, high-precision (with high reliability) second information extraction 1000 is performed.

[0308] Here, the first information used for reducing disturbance noise is related to at least one of optical disturbance noise reduction 1012 or electrical disturbance noise reduction 1012. However, it is not limited to that, and this first information may be related to both optical disturbance noise reduction and electrical disturbance noise reduction 1012.

[0309] The first or second information 1004 extracted within the signal processing unit 42 is information-transferred 1006 via the information transfer path 4. And the transferred information 1004 is stored 1010 within the collected information storage unit 74. Moreover, it is not limited to that, and it may be displayed 1008 to the user from the display unit 18 or the information providing unit 72. Furthermore, it may be transmitted to the external system 16 via the information transfer path 4.

[0310] As the transfer format 1014 used during this information transfer 1006, for example, existing color image signals or color video signal formats such as RGB (Red, Green, and Blue) may be used. Moreover, it is not limited thereto, and for example, multiplexing techniques defined by the MPEG (Moving Picture Experts Group) standard may be used. Specifically here, images and videos are time-divisionally dispersed and arranged within a video pack. And the information 1004 extracted within the signal processing unit 42 is stored within a unique information pack and inserted between the video pack sequences. This information pack may be uniquely defined for this embodiment, or the SP pack (Sub-picture Pack) defined by the DVD (Digital Versatile Disk) standard may be used. Furthermore, it may be described in a hypertext format (for example, XML (Extended Markup Language) format) similar to an HTML (Hyper Text Markup Language) document.

[0311] Here, the minimum unit of the output content obtained from the measurement unit 8 or the signal reception unit 40 is called 'data'. And the aggregate of that data or the connection relationship between data is called a'signal'. Also, the data processing, data analysis results of those data, or the results of processing that signal and signal analysis results are called 'information'. This data processing / analysis and signal processing / analysis are performed within the signal processing unit 42. That is, the measurement unit 8 or the signal reception unit 40 outputs data or signals toward the signal processing unit 42. And the signal processing unit 42 uses that data or signal to generate information and outputs this information toward the in-system control unit 50.

[0312] The content of the information generated by the signal processing unit 42 is basically information within the range that can be extracted or estimated from only the data and signals obtained by measurement in many cases. Then, the characteristic analysis / analysis processing unit 62 performs estimation and speculation of more advanced information. That is, the characteristic analysis / analysis processing unit 62 integrates the information output by the signal processing unit 42, the information stored in advance in the collection information storage unit 74, and the information collected from the external system 16 to perform estimation and speculation of more advanced information.

[0313] For example, in the spectral characteristics measured by the measurement unit 8, the light intensity values measured for each measurement wavelength correspond to the data. Also, when the measurement unit 8 measures an image such as a still image or a moving image, the intensity values and chrominance for each pixel correspond to the data. Further, for a data cube having spectral characteristic signals for each pixel, the light intensity values for each wavelength within a specific pixel correspond to the data.

[0314] Examples of the advanced information estimated and speculated by the characteristic analysis / analysis processing unit 62 include the user's preferences, the user's feelings and intentions that change over time, etc. Also, when providing a predetermined service to the user, the characteristic analysis / analysis processing unit 62 forms an identity in the cyber space. And this characteristic analysis / analysis processing unit 62 may serve as an agent to operate the identity in the cyber space or the robot in the real space.

[0315] FIG. 26B shows a list summarizing examples of the information used in the present embodiment. All of these examples of information are extracted / generated in the signal processing unit 42 using various signals (or various data) obtained from the measurement unit 8 and the signal reception unit 40. As described above, the information extracted first and used for disturbance noise reduction is the 'first information', and the information extracted after disturbance noise reduction using the first information corresponds to the'second information'. The examples of 'information' shown in FIG. 26B are a list of the first and second information combined. Therefore, all the information described in FIG. 26B may correspond to either the 'first information' or the'second information'. Also, the same information may be used as both the 'first information' and the'second information' at the same time.

[0316] When classifying the information related to this embodiment into category 1020, there are the effects of optical actions that occur unnecessarily along with measurement, information related to the shape and arrangement position of the measurement object 22, detection information of the moving object itself when the position of a specific part within the measurement object 22 moves, the composition ratio of the constituent parts within the measurement object 22, activities accompanied by time changes within the measurement object 22, and so on.

[0317] Optical actions that occur unnecessarily along with measurement occur in both the measurement of spectral characteristics and the measurement of image data (image signals). Among them, as a specific example 1024 of the optical actions occurring inside the measurement object 22, the light absorption αa1 of other components is mentioned. Also, in other specific examples 1024, there are light scattering characteristics αa2, light interference characteristics / light reflection characteristics α3, and so on.

[0318] Also, as an unnecessary optical action other than the above, the optical action on the surface of the measurement object 22 is mentioned. And as its specific example 1024, there also occurs a phenomenon where the detection light is refracted αb1 due to the surface inclination, and the imaging position within the detection optical system is shifted. Also, when the surface of the measurement object 22 has a fine uneven shape, the effects of diffraction and interference αb2 occur therefrom.

[0319] Moreover, the optical actions occurring in the middle of the light propagation path 6 are also significant as the effects of unnecessary optical actions. In particular, stray light αc1 mixed in the middle of the light propagation path 6 greatly reduces the optical measurement accuracy. Also, the state of light interference αc2 occurring in the middle of the light propagation path 6 may be collected as the first extraction information 1004. The signal processing unit 42 can perform arithmetic processing on the raw signal obtained from the measurement unit 8 or the signal reception unit 40 and remove the component of the first extraction information 1004 therefrom. Thereby, the second information with high measurement accuracy (and measurement reliability) can be extracted 1004.

[0320] The shape, position of the object to be measured 22, or the extraction information 1004 related to the detection of a moving object found therein is often obtained mainly through data analysis (signal analysis) of image data (or a data cube). That is, as specific examples 1024 of contour information and feature information of a shape corresponding to the extraction information outline 1022 included in the category 1020 related to the shape and position of the object to be measured 22, the information divided into regions β2 for each component within the image signal is applicable. This is obtained as a result of performing contour extraction of the shape included in the image data (image signal) within the signal processing unit 42.

[0321] Next, when performing a pattern matching operation on the contour shape, the blank area information β1 is extracted from the region division information β2 for each component within the image signal. For example, the blank area β1 within the data cube does not contain spectral characteristic information. Therefore, by using this blank area information β1 as the first extraction information and performing signal analysis (data analysis) of the spectral characteristics obtained from the areas other than the blank area to generate the spectral information only from the necessary locations as the second extraction information 1004, there is a merit of improving the efficiency of spectral characteristic analysis for the data cube. Moreover, not limited to this, if spectral characteristic analysis is performed only on the pixels corresponding to the important locations within the data cube, further improvement in the efficiency of spectral characteristic analysis can be achieved. Thus, if the position information β3 of the feature site within the image signal can be used as the first extraction information 1004, the efficiency in generating the second extraction information 1004 can be improved.

[0322] As the position information β3 of the feature site within the image signal, the contour information of the boundary region where this feature site exists may be used. Instead, if the center of gravity position information β4 of the feature site is output in the form of the corresponding pixel position information within the image sensor 300, it is possible to reduce the amount of information as the position information β3 of the feature site.

[0323] When a moving object such as an automobile, a ship, or an airplane is imaged in a background image, there is a method of using only the information of the moving object as the first extraction information 1004. In this case, the moving object region in the image corresponds to the extraction information 1004 as the outline 1022 of the extraction information. As specific examples 1024 of this moving object region, information γ1 on the range of the moving object region, the moving speed γ2 within the imaging element 300 of the center of gravity of the moving object, the time-series shape change information γ3 of the moving object itself, etc. can also be used as extraction information.

[0324] The extraction information 1004 mainly obtained by analyzing spectral characteristic signals includes content classified into categories 1020 such as the composition ratio of constituent parts and activities accompanied by time changes. In the spectral characteristic signals of infrared light (included in the wavelength range of 2.5 μm to 20 μm) and near-infrared light (included in the wavelength range of 0.8 μm to 2.5 μm) (including fluorescence spectroscopy and phosphorescence spectroscopy such as Raman scattering), information on light absorption caused by specific intramolecular vibrations and specific functional group (atomic group) vibrations is included. Therefore, when extracting the light absorption information of specific wavelength light or its time change included in these spectral characteristic signals, information on the composition ratio of the constituent substances in the measurement object 22 and information related to biological activities can be extracted 1004.

[0325] From the presence or absence of light absorption based on carbon compounds contained in the organic substance, it is possible to make a determination δa1 as to whether the measurement object 22 is composed of an organic substance or an inorganic substance. For example, when a methyl group or a methylene group is included, light absorption occurs in the range of 1.15 μm to 1.25 μm or in the range of 1.65 μm to 1.8 μm. On the contrary, in the case of an inorganic substance, light absorption rarely occurs within the above wavelength range.

[0326] Also, from the composition analysis result of the constituent components in the measurement object 22, it is possible to make a determination δa2 as to whether it is an animal, a plant, or an artificial object. Instead of proteins being contained in animals, saccharides are contained in plants. On the other hand, instead of the above methyl group and methylene group being contained in artificial objects, the detection of proteins and saccharides becomes rare. Thus, discrimination δa4 of saccharide / lipid / protein is possible from the wavelength range where a large amount of light absorption occurs.

[0327] Pure water exhibits significant light absorption particularly in the wavelength range of 1.4 μm to 1.5 μm and wavelengths of 1.8 μm and above. Therefore, based on the magnitude of light absorption in the above wavelength range, the moisture content δa3 can be estimated.

[0328] The protein structure, basic amino acids, and saturated and unsaturated fatty acids absorb light in the wavelength range described later using FIG. 31B. Therefore, based on the wavelength of light absorbed, the discrimination δa5 between the protein structure and basic amino acids and the degree of unsaturation δa6 of the fatty acid can be estimated.

[0329] Even when extracting information on the composition ratio of the same constituent part, the method of information extraction 1004 varies significantly depending on whether the measurement object 22 is a liquid or a solid that does not contain moisture. When a small amount of a specific substance is contained in a liquid, most of the spectroscopic characteristic signals obtained from the measurement unit 8 or the signal reception unit 40 contain spectroscopic characteristic information of the solvent. Therefore, in this case, it is necessary to extract the second spectroscopic characteristic information 1004 obtained from the characteristic substance after removing the spectroscopic characteristic information component of the solvent alone as the first extraction information 1004 from the spectroscopic characteristic signals obtained from the measurement unit 8 or the signal reception unit 40. Specific examples 1024 of the extraction information 1004 related to the content rate of substances in a liquid include the blood glucose level, the content rate δb1 of sugar components contained in urine, the content rate δb2 of specific substances in blood, and the like.

[0330] As the extraction information outline 1022 included in the information that changes with time as the category 1020 of the information extracted by the signal processing unit 42 in information extraction 1004, information related to biological activities is included. Specific examples 1024 thereof include the pulse and respiration rate ε1 of the user using the light utilization device 10, muscle contraction ε2, nervous system signal pulses generated during the firing of nerve cells (nerve impulse) and ion pump activity ε3 generated immediately thereafter, and chemical signal transmission ε4 occurring inside or between cells.

[0331] In FIG. 26B, individual symbols 290 are set for each specific example 1024 of the information to be extracted. To clarify the relationship between the detailed embodiment content to be described later and FIGS. 26B and 26A, the individual symbols 290 set here will also be cited in the subsequent description.

[0332] In order to improve the accuracy and reliability of the above information extraction 1004, optical disturbance noise reduction and electrical disturbance noise reduction 1012 are required. In particular, in this embodiment, by combining an optical noise reduction method and an electrical disturbance noise reduction method, high-precision (high-reliability) measurement is enabled. Before explaining the specific optical disturbance noise reduction and electrical disturbance noise reduction 1012, the causes 1036 of these disturbance noises will be explained.

[0333] FIG. 26C shows, in a list form, the causes 1036 of disturbance noise and the countermeasure methods 1038 for each measurement target area 1032 within the measurement object 22. The causes 1036 of electrical disturbance noise are the same regardless of the measurement target area 1032, corresponding to shot noise, thermal noise, electromagnetic induction noise, and the like.

[0334] As a countermeasure method 1038 for reducing electrical disturbance noise in this embodiment, the band limitation of the detection signal may be performed to extract only the carrier component E1. Moreover, in this embodiment, not limited thereto, lock-in amplification (Lock-in Amplifier) E2 may be performed. In this lock-in amplification E2, synchronization of the frequency and phase of the reference signal with respect to the detection signal is required. Therefore, in this embodiment, various information included in the category 1020 of activities with time variation in FIG. 26B may be used for the first extraction information 1004 to perform the above frequency and phase synchronization.

[0335] As other countermeasure methods 1038 for reducing electrical disturbance noise, an error correction function E3 of the digitized signal may be used. As a specific example, technologies such as PRML (Partial Response Most Likelihood) may be used to automatically correct to the signal sequence that seems to be the most appropriate.

[0336] The cause 1036 of optical external disturbance noise slightly differs according to the measurement target area 1032 in the object 22 to be measured. As a cause 1036 of optical external disturbance noise common to both, there is an influence of optical interference noise. And as a method for reducing this optical interference noise, in this exemplary embodiment, at least one of averaging (smoothing) L1 of interference noise components (averaging interference noise elements) and reduction L2 of the degree of coherence (reducing a degree of coherence) is performed.

[0337] Optical interference noise includes two different types of interference noise. Any of the interference noises is related to the coherence length ΔL0 corresponding to the length of the wave train. (That is, between adjacent wave trains before and after, they have an incoherent relationship with each other.) Also, when lights 202, 204, 206 having an incoherent relationship with each other are intensity-added, the interference noise components inherently generated in each of the lights 202, 204, 206 are averaged (smoothed) L1, and the amount of interference noise is reduced for any of the interference noises.

[0338] One of the above two different types of interference noise is caused by the temporal coherence of light and mainly appears in spectral characteristics. The reduction effect (a spectral degree of temporal coherence) of the interference noise caused by this temporal coherence has a relationship with the phase distribution characteristics in each of the lights 202, 204, 206, as already described with reference to FIGS. 8 to 11.

[0339] The other party is caused by the spatial coherence of light and mainly appears as spatial intensity unevenness. The occurrence situation of this spatial intensity unevenness is often called speckle noise. The reduction effect of interference noise (speckle noise amount or speckle constant Cs value) caused by this spatial coherence is related to the change in the irradiation angle of each light 202, 204, 206 when irradiating the measurement object 22. (Details will be described in Chapter 12.) However, not only that, even if the phase distribution characteristics change among the individual lights 202, 204, 206, the reduction effect of interference noise caused by spatial coherence could be confirmed.

[0340] Among the causes 1036 of other optical disturbance noises, there is the mixing of other optical actions. As a countermeasure method for this mixing of other optical actions in this embodiment, the signal processing unit 42 performs an arithmetic process (signal processing or signal analysis) L3 between the measurement signals to remove the influence of the mixed other optical actions. That is, when acquiring a measurement signal from the measurement unit 8 or the signal reception unit 40, the signal processing unit 42 extracts 1004 information based on the results of other optical actions from the measurement signal to generate first extraction information 1004. Then, the component of the first extraction information 1004 is removed from the measurement signal. As a result, second information extraction 1000 is performed after the influence of other optical actions is removed.

[0341] As the cause 1036 of the optical disturbance noise generated according to the measurement target area 1032 in the measurement object 22, there is a cause 1036 that does not occur during the overall characteristic measurement of the entire measurement object 22 and only occurs when measuring only the local characteristics within the measurement object 22. As the cause 1030 of the optical disturbance noise, there is the influence of external disturbance light mixed in from outside the local area to be measured.

[0342] As a method 1038 for reducing the influence of disturbing light that enters from outside the local area to be measured, in this exemplary embodiment, an aperture restriction may be provided at the imaging position or confocal position with respect to the local area to be measured to block unnecessary disturbing light L4. Based on this, for example, when performing three-dimensional measurement inside the measurement object 22, it is possible to prevent mismeasurement of the detection light from a depth position outside the local area to be measured as disturbing light.

[0343] Also in FIG. 26C, individual symbols 290 are set for each disturbing noise reduction countermeasure method 1038. To clarify the relationship between the detailed embodiment content to be described later and FIGS. 26C and 26A, the individual symbols 290 set here will also be cited in the subsequent description.

[0344] Chapter 11 Mechanism in which wave trains are continuously repeatedly generated along the light propagation direction FIG. 27A shows the characteristics near the end region of one wave train obtained as a result of experimental measurement. The vertical axis of FIG. 27A represents the light transmittance when panchromatic light (light having a plurality of different wavelength lights within a wide wavelength range) emitted from a halogen lamp passes through a glass plate with a thickness of 138.40 μm. Here, the horizontal axis of FIG. 27A represents the measurement wavelength λ0 of the panchromatic light, and the light transmittance characteristics for each wavelength λ0 from 1.3 μm to 1.6 μm can be understood from FIG. 27A.

[0345] When each wavelength light passes through the glass plate, optical interference occurs between the zero-order transmitted light that travels straight inside the glass plate and the first-order reflected light that is reflected twice at the entrance and exit surfaces inside the glass plate. Therefore, the amount of change in the amplitude of the light transmittance oscillation between the measurement wavelengths in FIG. 27A represents both the interference visibility and the magnitude of the wave train amplitude. Therefore, the vicinity where the measurement wavelength λ0 is near 1.32 μm corresponds to the end region of one wave train.

[0346] The theoretical calculation results shown in Fig. 27A represent the results of theoretical calculations using Equation 11. Since the wavelength resolution Δλ of the spectroscope used in this experiment is around 7.5 nm, the coherence length ΔL0 corresponding to the length along the optical propagation direction of one wave train can be calculated from Equation 1.

[0347] Fig. 27B shows a conventionally known mechanism model of wave train formation. The horizontal axis in Fig. 27B represents the spatial distance along the optical propagation direction. The vertical axis in Fig. 27B represents the electric field amplitude at a predetermined time.

[0348] When the central wavelength of one wave train is λ0, Fig. 27B(c) shows the electric field amplitude distribution of the wavelength light with the central wavelength λ0 at a predetermined time. Fig. 27B(a) shows the electric field amplitude distribution of the wavelength light with a wavelength of λ0 - Δλ / 2. Similarly, Fig. 27B(b), Fig. 27B(d), and Fig. 27B(e) show the electric field amplitude distributions of the wavelength lights with wavelengths of λ0 - Δλ / 4, λ0 + Δλ / 4, and λ0 + Δλ / 2, respectively. Similarly, Fig. 27B(f) represents the electric field amplitude distribution of the entire wave train obtained by adding the amplitudes of each wavelength light (amplitude synthesis or addition of electric field amplitude values).

[0349] Consider the case where the phases of all the wavelength lights in Fig. 27B(a) to (e) coincide at the α position. Here, since the electric field amplitudes of all the wavelength lights take the maximum value, the amplitude of the wave train obtained by adding the amplitudes is the maximum. However, since the wavelengths of each wavelength light are different, a phase shift occurs between each wavelength light as it moves from the α position to the β position. Therefore, at the β position shifted by the coherence length ΔL0 from the α position, the electric field amplitude values of each wavelength light become random. As a result, the amplitude of the wave train obtained by adding the amplitudes at the β position becomes "0". And the β position in Fig. 27B corresponds to the vicinity of the end region of one wave train when the measured wavelength λ0 in Fig. 27A is near 1.32 μm.

[0350] According to the conventionally known mechanism model of wave train formation, there is no place where the phases of each wavelength light coincide at positions farther than the β position (γ position or δ position). Therefore, the conventionally known mechanism model of wave train formation cannot explain the principle of continuously repeating generation of wave trains along the optical propagation direction.

[0351] Furthermore, in the conventionally known mechanism model of wave train formation, 1. A small-amplitude wave train appears at the γ position, and 2. The wave train phase here is inverted with respect to the wave train phase between the α position and the β position. However, as long as the measurement data shown in FIG. 27A were carefully examined in detail, the experimental results predicted in 1. and 2. above were not obtained. From this experimental result, it is predicted that "a mechanism other than the conventionally known mechanism model of wave train formation is at work, in which the wave train is continuously and repeatedly generated." For the first time in this specification, a mechanism model in which the wave train is continuously and repeatedly generated is proposed.

[0352] When one wave train includes (amplitude-added or amplitude-value synthesized) wavelength light (plane wave) from λ0 - Δλ / 2 to λ0 + Δλ / 2 as shown in FIGS. 27B(a) to (f), the relational expression of this wave train is

[0353]

Equation

[0354]

Equation

[0355]

Equation

[0356]

Equation

[0357]

Number

[0358]

Number

[0359] The right side above Equation 29 represents the 'preceding (earlier-occurring) wave train' near the terminal region. Also, the equation below Equation 29 represents the vicinity of the starting region of the 'following (later-occurring) wave train'. A particularly notable point is that a'reversal of the phase angle progression direction' occurs between the right side above Equation 29 and the equation below.

[0360] In the conventionally known wave train formation mechanism model, there is no location where the phases of lights of each wavelength match at locations farther from the β position (γ position and δ position), and the 'following wave train' does not occur. However, when a 'change in the direction of the phase angle' occurs near the terminal region of the 'preceding wave train' (near the β position in Fig. 27B), synchronization of the phases between lights of each constituent wavelength starts immediately thereafter. As a result, the 'following wave train' is generated.

[0361] In electromagnetics, electromagnetic waves propagate in space due to the interaction between an oscillating electric field and an oscillating magnetic field that occur in mutually perpendicular directions. However, near the terminal region of the 'preceding wave train', the phases of the oscillating electric field and the oscillating magnetic field are in a random situation among lights of different wavelengths. And this random state of the oscillating electric field and the oscillating magnetic field may form the soil that gives rise to a'reversal of the phase angle progression direction'.

[0362] However, the spatial range that satisfies the condition of Equation 28 has a certain degree of width. In other words, the starting position of the "following wave train" within the ending region of the "leading wave train" is not uniquely determined. Therefore, a random phase shift occurs between the "leading wave train" and the "following wave train." As a result (because the phase is not fixed), a "non-interfering" relationship is created between the "leading wave train" and the "following wave train." In other words, when a random phase shift occurs between the leading and trailing wave trains that are continuously and repeatedly generated, combining the leading and trailing wave trains and integrating them over time will produce essentially the same result as "intensity addition (combining intensity values)."

[0363] The difference between the mechanistic model for the continuous and repeated generation of wave trains described above and the conventionally known mechanistic model for wave train formation will be explained from another perspective. As shown in Figure 27B(f), in the conventionally known mechanistic model for wave train formation, the phase angle change is fixed near the terminal position (β position) of the leading wave train. This not only inhibits the generation of the trailing wave train, but also causes a phase reversal at the γ position (which contradicts the experimental results). In contrast, in the mechanistic model for the continuous and repeated generation of wave trains, the phase angle direction is reversed near the terminal position (β position) of the leading wave train, and a trailing wave train with a randomly changing phase is continuously generated.

[0364] In this embodiment, optical interference noise is reduced by utilizing the principle of wave train generation, which occurs continuously and repeatedly along the light propagation direction. Specifically, within the optical system included in the optical utilization device 10 or the service providing system 14 used in this embodiment, a first region 212 and a second region 214 are configured, whose optical path lengths differ by at least twice the coherence length ΔL0. The initial light 200 emitted from the light-emitting unit 470 undergoes wavefront division or amplitude division. As a result, a portion of the initial light 200 passes through the first region 212 as first light 202. At least a portion of the remaining initial light 200 passes through the second region 214 as second light 204. The first light 202 after passing through the first region 212 and the second light 204 after passing through the second region 214 are intensified (combined in terms of optical intensity).

[0365] Since repetitive wave trains are continuously generated along the light traveling direction, different wave trains are necessarily included in the first light 202 and the second light 204 during intensity addition (optical intensity synthesis). Since the difference in optical path length between the first region 212 and the second region 214 is separated by a coherence length ΔL0 (or more precisely, twice the coherence length) or more, the first wave train included in the first light 202 and the second wave train included in the second light 204 do not interfere with each other.

[0366] There is a possibility that first interference noise is generated within the first wave train included in the first light 202, and second interference noise is generated within the second wave train included in the second light 204. However, the characteristics of the first interference noise and the second interference noise are different from each other, and they do not interfere between the first wave train and the second wave train. Therefore, the intensity addition (optical intensity synthesis) of both causes averaging (smoothing) between the first and second interference noises. As a result of this averaging process, a cancellation effect occurs between the mutual interference noises, reducing the overall interference noise.

[0367] Chapter 12 Method for Reducing Spatial Interference Noise (Interference Noise Caused by Spatial Coherence) Speckle noise is known as optical interference noise generated by light with a high degree of spatial coherence, such as laser light. As an example of this embodiment, an explanation of the averaging L1 method of this interference noise component will be given.

[0368] Figure 28A(a) shows the basic principle of the generation of spatial interference noise. Two light reflection regions 1046 separated by an interval P are arranged. Incident light 1042 is perpendicularly incident on the light reflection region 1046, and Figure 28A(a) shows the reflection intensity of the reflected light 1048 reflected in the θ0 direction. According to the optical interference theory, the reflection intensity at that time is proportional to cos 2 (πPθ0 / λ). Here, the important thing 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 spatial interference noise.

[0369] Consider further expanding FIG. 28A and the case where a plurality of light reflection regions 1046 are regularly arranged with 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 plurality of light reflection regions 1046. Therefore, there are locations where the reflected amplitudes from adjacent light reflection regions 1046 reinforce each other and appear bright, and locations where the reflected amplitudes cancel each other out and appear dark. Such an appearance is called a speckle noise pattern.

[0370] FIG. 28A(b) shows the reflection intensity of the reflected light 1048 reflected in the θ0 direction when the incident angle of the incident light 1042 on the two light reflection regions 1046 changes to θ i According to the theory of light interference, the reflection intensity at that time changes as cos 2 {πP(θ0 - θ i ) / λ}.

[0371] Since different wave trains do not interfere with each other, it was explained in the previous chapter that combining light between different wave trains corresponds to intensity addition (synthesis of light intensity values). For example, as shown in FIG. 28A(a), the first light 202 including at least a part of one wave train is perpendicularly incident on the two light reflection regions 1046. At the same time, the second light 204 including at least a part of another wave train that does not interfere with the above wave train is incident at an incident angle of θ i . 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 value of θ i is optimized so that the light intensity of the second term becomes minimum when the light intensity of the first term is maximum, the maximum and minimum of the light intensity are canceled out (averaged or smoothed). As a result, the spatial interference noise is significantly reduced.

[0372] That is, when the first light 202 and the second light 204, which are in a non-interfering (or low-interference) relationship with each other, are simultaneously irradiated onto the measurement object 22 while changing the irradiation angles with respect to each other, the optical interference noise (speckle noise) based on the spatial coherence of the light can be reduced. In FIG. 28A, for simplicity of explanation, it was described only by the intensity addition of only two lights 202 and 204 that are non-interfering (or low-coherent) with each other. However, it is not limited thereto, and three or more (or four or more) types of lights 202, 204, and 206 that are in a non-interfering relationship with each other may be simultaneously irradiated onto the measurement object 22 while changing the irradiation angles. When the number of irradiations of non-interfering (or low-coherent) lights is increased, the averaging number of the optical interference noise (speckle noise) increases, so that the reduction effect of the interference noise increases.

[0373] Generally, critical illumination and Koehler illumination are known as illumination methods of light for the measurement object 22. In order to efficiently exhibit the reduction effect of the interference noise, it is desirable that a plurality of lights 202, 204, and 206 that are non-interfering (or low-coherent) with each other overlap and irradiate an arbitrary same location within the measurement object 22. Therefore, as the illumination method of light for the measurement object 22 in the present exemplary embodiment, it is desirable to use Koehler illumination.

[0374] In the present exemplary embodiment, the initial light 200 emitted from the light emitting unit 470 is divided to generate lights 202, 204, and 206 that are in a non-interfering (or low-interfering) relationship with each other (lights including different wave trains from each other using the description content of the previous chapter). When amplitude division is used as the division method of the initial light 200 at this time, it is difficult to increase the substantial number of divisions. Therefore, in the present exemplary embodiment, when the wavefront division method is used to divide the initial light 200, there is an effect that the number of divisions into lights 202, 204, and 206 that are in a non-interfering (or low-interfering) relationship with each other can be increased.

[0375] As described above, when the traveling directions of the lights 202, 204, and 206 that are in a non-interference (or low-interference) relationship with each other are inclined with respect to each other, the optical interference noise (speckle noise) based on the spatial coherence of the lights can be efficiently reduced. Specific embodiments of the method of inclining the traveling direction for each of the lights 202, 204, and 206 that are in a non-interference (or low-interference) relationship will be sequentially described below.

[0376] FIG. 28B shows an example of a method for reducing optical interference noise using a single-core multimode optical fiber. FIG. 28B(a) shows the characteristics of the emitted light 1044 when the incident light 1042 is focused at the center on the incident surface of the core region in the optical fiber or the optical guides 330 / 332 / 340.

[0377] In the state of FIG. 28B(a), most of the lights in the incident light 1042 travel straight through the center of the core region in the optical fiber or the optical guides 330 / 332 / 340. As a result, the intensity distribution of the emitted light 1044 shows the highest intensity along the direction along the optical axis center on the emission surface, and shows an approximately axially symmetric intensity characteristic. When the central position on the emission surface in the core region in the optical fiber or the optical guides 330 / 332 / 340 is made to coincide with the front focal position of the collimating lens 318, the emitted light 1044 after passing through the collimating lens 318 becomes parallel light. And the traveling direction of this parallel light coincides with the optical axis of the collimating lens 318.

[0378] FIG. 28B(b) shows the characteristics of the emitted light 1044 when the incident light 1042 is focused on the outer side (i.e., the position close to the cladding region 334) on the incident surface of the core region in the optical fiber or the optical guides 330 / 332 / 340. In this case, most of the lights in the incident light 1042 are multiply reflected near the interface between the core region in the optical fiber or the optical guides 330 / 332 / 340 and the cladding region 334. As a result, the intensity distribution of the emission cross section of the emitted light 1044 from the core region in the optical fiber or the optical guides 330 / 332 / 340 tends to be, for example, a 'doughnut-shaped intensity distribution' with a low intensity in the center and a high intensity in the periphery.

[0379] The core diameter of a single-core multimode optical fiber is often larger than that of a single-mode optical fiber. As a specific example, while the core diameter of a single-mode optical fiber is 3 μm to 5 μm, the core diameter of a multimode optical fiber is often 30 μm or more and 2000 μm or less (for example, standard sizes are 220 μm and 600 μm). Therefore, the emitted light 1044 emitted from the inner peripheral portion of the core of the multimode optical fiber, after passing through the collimating lens 318, has its traveling direction inclined by θ with respect to the optical axis of the collimating lens 318. By changing the condensing incident position of the single-core multimode optical fiber in this way, the traveling direction after passing through the collimating lens 318 changes, and optical interference noise is reduced.

[0380] Actually, in an optical fiber, it is considered that the object should be analyzed wave-optically as the light intensity distribution mode of the cross-section of the core region, rather than being interpreted geometrically. However, in FIG. 28B, for the sake of convenience of explanation, it is described in terms of the difference in the optical paths passing through the core region in the optical fiber or in the optical waveguides 330 / 332 / 340.

[0381] As described above, lights 202, 204, and 206 having a non-interfering (or low-interfering) relationship with each other may be passed through a waveguide element (an optical fiber, an optical waveguide, or an optical element having a structure in which optical waveguides are integrated on the same substrate) that allows multimoding of internal traveling waves, and the emitted light from the waveguide element may be used to irradiate the measurement object 22 with Keller illumination. By using Keller illumination in this way, it is easy to simultaneously irradiate an arbitrary same point in the measurement object 22 with non-interfering (or low-interfering) lights 202, 204, and 206 having different irradiation angles. Based on this, optical interference noise can be easily reduced.

[0382] Incidentally, the above method is also effective in reducing optical interference noise that appears in the spectral characteristics mainly caused by the temporal coherence of light. In FIGS. 28B(a) and 28B(b), the optical paths passing through the core region in the optical fiber or in the optical waveguides 330 / 332 / 340 are different. Therefore, it is considered that the phase distribution included in the emitted light 1044 is significantly different between FIGS. 28B(a) and 28B(b).

[0383] FIG. 28C shows an application example of the optical interference noise reduction method described in FIG. 28B. An optical property conversion element 210 formed of an optically transparent material having a refractive index n constitutes a first region 212 and a second region 214. When the difference in optical path length between the two becomes larger than the aforementioned coherence length ΔL0 (or twice thereof), the degree of partial coherence between the first light 202 and the second light 204 that have passed through the respective regions 212 and 214 is significantly reduced.

[0384] If the slope angles between the incident surface and the exit surface in each of the regions 212 and 214 are made different from each other, when the incident angle of the initial light 200 is the same, the exit angles between the first light 202 and the second light 204 are different from each other. Therefore, by optimizing the exit angles between the first light 202 and the second light 204 that are non-interfering (or have low coherence) with each other, the optical interference noise reduction described in FIG. 28B can be efficiently performed.

[0385] Here, the difference value between the two exit angles is represented by θ. Immediately after this, a condenser lens 314 with a focal length F is arranged, and the incident surface of the in-fiber core region or the optical guides 330 / 332 / 340 is made to coincide with the rear focal plane position of this condenser lens 314. Then, the condensing positions of the two deviate by Fθ on the incident surface of the in-fiber core region or the optical guides 330 / 332 / 340.

[0386] Let the width in the in-fiber core region or the optical guides 330 / 332 / 340 be represented by W. When the deviation amount Fθ of the two condensing positions exceeds W, the amount of light of one of the first light 202 and the second light 204 that enters the in-fiber core region or the optical guides 330 / 332 / 340 is significantly reduced. Therefore, it is desirable to satisfy the condition of Fθ≦W.

[0387] According to the teachings of the diffraction theory of light, the lights 202 and 204 at the condensing position have a predetermined spread. Therefore, even under the condition of Fθ>W, a part of both lights enters the in-fiber core region or the optical guides 330 / 332 / 340. Therefore, as a minimum essential condition, it is necessary that Fθ>W / 2.

[0388] As shown in FIG. 28B, it is desirable that the optical paths in the fiber core region or in the optical waveguides 330 / 332 / 340 are different between the first light 202 and the second light 204 that do not interfere with each other (or have low interference). As a condition for the optical paths of both to be different, Fθ≦W / 1000 (preferably Fθ≦W / 1000) is required.

[0389] Summarizing the above description results, the range of the angle θ formed between the first light 202 that has passed through the first region 212 and the second light 204 that has passed through the second region 214 is W / (100F)≦ θ ≦ W / (2F) (preferably W / (1000F)≦ θ ≦ W / F).

[0390] As an application example of this embodiment, instead of using a single-core fiber, a bundle fiber 1040 may be used. FIG. 28D(a) shows an application example using the bundle fiber 1040. The light source unit 2 is composed of a light emitting unit 470 and an optical characteristic control unit 480. Then, the first light 202 and the second light 204 that do not interfere with each other (or have low interference) emitted from this light source unit 2 are irradiated onto the measurement object 22 by the Köhler illumination system 1026. The focal length of the collimating lens 318 installed in this Köhler illumination system 1026 controls the value of the irradiation angle difference between the first light 202 and the second light 204 irradiated onto the measurement object 22. Here, when the focal length of the collimating lens 318 is short, the irradiation angle difference between the two becomes large.

[0391] In the optical characteristic conversion element 210 arranged in the optical characteristic control unit 480, the thickness is different between the first region 212 and the second region 214. And when the optical path length between the two exceeds the coherence length ΔL0 (or twice thereof), the interference between the first light 202 and the second light 204 decreases.

[0392] The light-collecting lens 314 collects the first and second lights 202, 204 on the incident surface of the bundle fiber 1040. Here, the first light 202 and the second light 204 enter different core regions in the bundle fiber 1040, respectively. The combination of the difference in the passing core regions and the collimating lens 318 changes the traveling directions between the lights 202, 204 exiting the bundle fiber 1040.

[0393] FIG. 28D(b) shows an optical system in which the phase characteristic conversion element 1050 is arranged immediately before the incident surface of the bundle fiber 1040 as compared with FIG. 28D(a). The first and second lights 202, 204 passing through the phase characteristic conversion element 1050 each enter the bundle fiber 1040 with their phase characteristics converted. Specifically, as the phase characteristic conversion element 1050, a diffusion plate having a fine structure on its surface, such as ground glass, may be used. Moreover, not limited thereto, a grating, a hologram element, a Fresnel zone plate, or the like may be used.

[0394] At the beginning of this chapter, it was explained that the change in the irradiation angle with respect to the measurement object 22 is most effective for reducing interference noise caused by spatial coherence. However, not limited thereto, the difference in the phase distribution between the lights 202, 204 that are non-interfering (or low-interfering) with each other has also been experimentally confirmed to be effective in reducing interference noise caused by spatial coherence. That is, as an experimental result, the optical system of FIG. 28D(b) is more effective in reducing interference noise caused by spatial coherence than the optical system of FIG. 28D(a).

[0395] FIG. 28D(c) shows that the phase characteristic conversion element 1050 is arranged near the light-collecting surfaces of the first light 202 and the second light 204 as compared with FIG. 28D(b). In FIGS. 28D(a) and 28D(b), mainly, the first light 202 and the second light 204 pass through different core regions in the bundle fiber 1040 separately. In contrast, in FIG. 28D(c), the first light 202 and the second light 204 are mixed with each other when passing through the phase characteristic conversion element 1050. As a result, the first light 202 and the second light 2 continue to pass through the same core region in the bundle fiber 1040.

[0396] FIG. 28E shows another example in the present embodiment. As a method of overlappingly irradiating while changing the irradiation angles of the respective lights 202, 204, 206 that have passed through different regions 212, 214, 216 onto the light irradiation object 1030, a phase characteristic conversion element 1050 such as a diffusion plate is used. Since the surface of the phase characteristic conversion element 1050 has a fine uneven shape, the light passing through it is diffused. And the irradiation angles to an arbitrary position on the light irradiation object 1050 change to θ1, θ2, θ3 for the first light 202, the second light 204, and the third light 206. At the same time, at this position, the first light 202, the second light 204, and the third light 206 are overlappingly irradiated.

[0397] Since the respective irradiation angles are different, the pattern of the optical interference noise (speckle noise) appearing on the light irradiation object 1050 is different between the first light 202, the second light 204, and the third light 206. Since the relationship between the first light 202, the second light 204, and the third light 206 is non-interference (or low interference), different optical noise patterns are mixed on the light irradiation object 1030. As a result, the averaging (smoothing) of the optical noise pattern is performed, and the overall interference noise is reduced.

[0398] FIG. 28F shows an application example in the present embodiment. In FIG. 28F, the lights 202, 204, 206 that are non-interference (or low interference) with each other are focused at spatially different positions. When the Köhler illumination system 1026 is adopted as the illumination system for the light irradiation object 1030, the lights 202, 204, 206 focused at these different positions are mixed with each other (overlapped) and irradiated to an arbitrary position within the light irradiation object 1030. Also, the irradiation angles at this time are different from each other. As a result, the averaging (smoothing) of the optical interference noise pattern (speckle noise pattern) occurs, and the overall optical interference noise (speckle noise) is reduced.

[0399] As a method of spatially condensing lights 202, 204, and 206 that are non-interfering (or low-interfering) with each other, in FIG. 28F, a fly-eye lens 1028 having a plurality of optical axes is arranged on the same space. In FIG. 28F(a), this fly-eye lens 1028 is arranged immediately after the optical property conversion element 210. Also, in FIG. 28F(b), this fly-eye lens 1028 is arranged immediately before the optical property conversion element 210 and is integrally formed with the optical property conversion element 210.

[0400] In both FIG. 28F(a) and FIG. 28F(b), the third, second, and first lights 206, 204, and 202 that have passed through the third, second, and first regions 216, 214, and 212 respectively are condensed at the α position, β position, and γ position. Here, with the adoption of the Köhler illumination system 1026, the lights 206, 204, and 202 after passing through each condensing position are mixed and irradiate the light irradiation object 1030 with different irradiation angles.

[0401] As a method of condensing the lights 206, 204, and 202 passing through different regions 216, 214, and 212 at different positions α, β, and γ, in the example of FIG. 28F, a fly-eye lens 1028 is used. However, it is not limited thereto, and they may be condensed at different positions α, β, and γ by any other method. As another example of an embodiment, a liquid crystal lens array may be used instead of the fly-eye lens 1028.

[0402] FIG. 28G shows the experimental results of the actually conducted effect confirmation. The horizontal axis of FIG. 28G represents the moving position on the surface of the measurement object 22. Also, the vertical axis of FIG. 28G represents the light intensity that appears on the imaging element of the camera. As the measurement object 22, a diffusion plate with an Ra value (a value of average roughness) representing the average value of the surface unevenness height of 2.8 μm was used.

[0403] FIG. 28G(a) shows the optical interference noise pattern when the conventional light passing through the core region in a single-core optical fiber or the center in the optical guides 330 / 332 / 340 is irradiated onto the measurement object 22. In FIG. 28G(a), the variation in light intensity is large, and large optical interference noise (speckle noise) appears.

[0404] Figure 28G(b) shows the optical interference noise pattern when the optical system of Figure 28D(b) is adopted. Quartz glass is used as the material of the optical conversion element 210, and it is composed of 48 divided elements with different thicknesses of 1 mm each. A diffuser plate with an Ra value of 0.5 μm is used for the phase characteristic conversion element 1050. The length of the bundle fiber 1040 is 1.5 m, and 320 cores with a core diameter of 230 μm (NA (numerical aperture) 0.22) are bundled within a diameter range of 5 mm. The focal lengths of both the condenser lens 314 and the collimating lens 318 are set to 50 mm.

[0405] Compared with Figure 28G(a), the optical interference noise (speckle noise) in Figure 28G(b) is significantly reduced.

[0406] Chapter 13 Measuring Object Form - Compatible Containers and Measuring Optical Systems Corresponding to Measuring Object Regions Figure 29A(a) shows an example of the holding container structure for the measuring object 22 in this embodiment. In this embodiment example, as the form of the measuring object 22, a holding container that can measure not only solids but also liquids and gases with good reproducibility under the same conditions is provided. When the measuring object 22 is a liquid or a gas, the measurement data changes significantly according to the change in the thickness t3 of the measuring object installation region 1052 where it is set. As a countermeasure, in this embodiment example, the measuring object installation region 1052 has a structure in which the thickness t3 can be determined to be constant. Specifically, the measuring object installation region 1052 is sandwiched between an upper light - transmitting member 1064 and a lower light - transmitting member 1062 through a spacer 1056 with the thickness t3 strictly controlled. By adopting this simplified structure, not only can the holding container be provided to the user at a very low cost, but also the thickness t3 of the measuring object installation region 1052 can be accurately reproduced.

[0407] Also, as described above, since the holding container structure of Fig. 29A(a) can be fabricated very inexpensively, it becomes easy to "dispose of" every time the user makes a measurement. In the optical utilization device 10 shown in this embodiment example, very high-precision measurement is required. Therefore, when the same holding container is reused for different measurements, fragments of the measurement object 22 measured previously may remain in the holding container, and there is a risk that the measurement data detected from these fragments may deteriorate the current measurement accuracy. If the holding container can be "disposed of" for each measurement in this way, not only will the measurement accuracy be improved, but the convenience for the user will also be greatly enhanced.

[0408] The materials of the upper light-transmitting member 1064 and the lower light-transmitting member 1062 used in Fig. 29A(a) or (b) are preferably inorganic substances. When the upper light-transmitting member 1064 and the lower light-transmitting member 1062 are made of an organic substance, methyl groups and methylene groups contained in the organic substance strongly absorb light with a wavelength around 1.7 μm. Therefore, when measuring the spectral characteristics of the measurement object 22 up to the wavelength range around 1.7 μm, it is not preferable to use an organic substance. Also, in commonly used blue plate glass and optical glass, a large amount of hydroxyl groups are often mixed in during manufacturing. Therefore, as the materials of the upper light-transmitting member 1064 and the lower light-transmitting member 1062, inorganic materials with a small amount of hydroxyl group mixing (such as silicate glass, anhydrous glass, anhydrous quartz, etc.) are desirable.

[0409] The regions of both the upper light-transmitting member 1064 and the lower light-transmitting member 1062 adjacent to the measurement object installation region 1052 correspond to the light propagation path 6 through which the detection light passes. Therefore, in order to prevent the user from accidentally touching this region, it is integrated (adhered) with the outer peripheral holding member 1066 at the outer peripheral portion of the lower light-transparent member 1062. The user moves the holding container by holding the outer peripheral portion of the outer peripheral holding member 1066. In this way, the outer peripheral holding member 1066 that can be directly touched by the user is formed outside the light propagation path 6 through which the light passes, improving the convenience for the user.

[0410] As shown in Fig. 29A, the inner diameter of the outer holding member 1066 (the inner hole portion) is slightly wider than the outer diameter of the spacer 1056. Therefore, the thickness of the measurement target installation area 1052 can be accurately defined only by the thickness of the spacer 1056 without being affected by the thickness of the outer holding member 1066.

[0411] Furthermore, a gap is provided between the inner side of the side wall portion of the outer holding member 1066 and the outer side of the upper light transmission member 1064, and the structure is such that a jig such as tweezers can be inserted into this gap. Then, while supporting the outer peripheral portion of the upper light transmission member 1064 with a jig such as tweezers inserted into this gap, the upper light transmission member 1064 can move up and down with respect to the outer holding member 1066. With this structure, the convenience for the user of the holding container is improved. Here, when the value 2S of the difference between the inner diameter of the side wall portion of the outer holding member 1066 and the outer diameter of the upper light transmission member 1064 is set to 1 mm or more and 2 m or less (preferably 4 mm or more and 4 cm or less), the convenience for the user can be ensured.

[0412] For example, when the measurement object 22 is a liquid, this measurement target installation area 1052 is filled with the liquid. And when sandwiching with the upper light transmission member 1064 and the lower light transmission member 1062 via the spacer 1056 with respect to this measurement target installation area 1052, there is a risk that a part of the above liquid overflows and leaks into the light propagation path 6. To prevent this risk, a structure is provided in which the surplus material absorption member 1068 made of a material with high water absorption can be arranged. Therefore, when sandwiching with the upper light transmission member 1064 and the lower light transmission member 1062 via the spacer 1056 with respect to the measurement target installation area 1052, this surplus material absorption member 1068 absorbs the overflowed liquid. By the water absorption action of this surplus material absorption member 1068, it is possible to prevent a part of the stain in the light propagation path 6 generated by the overflowed liquid riding on the upper light transmission member 1064. As a result, stable and highly accurate measurement becomes possible.

[0413] Here, if the inner diameter of the surplus material absorbing member 1068 is made larger than the outer diameter of the spacer 1056 and the outer diameter of the surplus material absorbing member 1068 is set smaller than the inner diameter of the side wall portion of the outer holding member 1066, the surplus material absorbing member 1068 can be properly installed on the inner upper surface of the outer holding member 1066. Also, if fluff or dust comes out from the surplus material absorbing member 1068, there is a risk that this fluff or dust may be erroneously measured and the measurement accuracy may deteriorate. Therefore, as the material of the surplus material absorbing member 1068, a material from which it is difficult for fluff or dust to come out (for example, non-woven fabric, filter paper, or special paper used in a clean room) is desirable.

[0414] FIG. 29A(c) shows an example of a holding container structure used to obtain spectroscopic data in a state where the object to be measured 22 is absent. For example, when measuring the spectroscopic characteristics of the object to be measured 22, it is often the case that the ratio (difference on a log scale) between the spectroscopic characteristics with and without the object to be measured 22 is taken. Therefore, first, the spectroscopic data in a state where the object to be measured 22 is absent is acquired using the holding container shown in FIG. 29A(c). Then, the spectroscopic data from the object to be measured 22 is acquired in the holding container shown in FIG. 29A(a).

[0415] In the structure of FIG. 29A(c), a light transmissive member 1054 with a predetermined thickness is installed inside the outer holding member 1066. As described above, it is desirable that the upper light transmissive member 1064 and the lower light transmissive member 1062 be made of an inorganic material with a low hydroxyl group content. However, some hydroxyl groups are mixed in certain types of fused quartz, and light absorption to some extent occurs in the wavelength range around, for example, 1.4 μm for the light passing through the upper light transmissive member 1064 and the lower light transmissive member 1062. Therefore, in this embodiment, it is desirable that the upper light transmissive member 1064 and the lower light transmissive member 1062 use exactly the same material, and that the light transmissive member 1054 with the predetermined thickness described in FIG. 29(c) also use the same material. Furthermore, in order to match the absorption amount of light with a wavelength around 1.4 μm, which is generated due to the influence of the thickness, the thickness of the light transmissive member 1054 with the predetermined thickness is desirably the sum value t1 + t2 of the thickness t1 of the lower light transmissive member 1062 and the thickness t2 of the upper light transmissive member 1064. Here, if the dimensional error between the sum value t1 + t2 of the thickness t1 of the lower light transmissive member 1062 and the thickness t2 of the upper light transmissive member 1064 and the thickness of the light transmissive member 1054 with the predetermined thickness is 1 mm or less, or 0.2 mm or less (desirably 0.1 mm or less), high measurement accuracy can be ensured.

[0416] As will be described later, there may be cases where the measurement object 22 is composed of a plurality of different materials (different compositions), and it is desired to measure the spectroscopic characteristics of only a specific material (specific composition) among them. In this case, the spectroscopic data obtained from the materials (compositions) outside the measurement target inhibits the measurement accuracy αa1. In this embodiment, in order to ensure high measurement accuracy, the characteristics of the inhibition factor αa1 are extracted in advance as the first extraction information 1004, and the first extraction information is used to reduce the disturbance noise and perform the second information extraction 1000 regarding the spectroscopic characteristics of only the specific material (specific composition) to be measured.

[0417] FIG. 29A(b) shows an example of a holding container structure used to extract in advance the characteristics of this pre-inhibition factor αa1. Basically, it has the same structure as FIG. 29A(a), and only the measurement object installation area 1052 is changed to the known substance installation area 1058. Many living organisms contain a large amount of water. Alternatively, when obtaining the characteristic information of specific cells during culture in a culture medium, the extraction information 1004 from the culture medium itself is mixed in as external disturbance noise. Therefore, the holding container structure for extracting the spectroscopic characteristic information of pure water or the spectroscopic characteristic information of the culture medium itself corresponds to FIG. 29A(b) as the information 1004 to be extracted in advance. That is, in this case, pure water or a culture medium is filled as the known substance installation area 1058 within the location of the measurement object installation area 1052 in FIG. 29A. Here, similar to FIG. 29A(a), in FIG. 29A(b), the lower light transmissive member 1062, the known substance installation area 1058, and the upper light transmissive member 1064 correspond to a part of the light propagation path 6.

[0418] FIG. 29B shows an example of the procedure for holding the measurement object 22 in the holding container described above. As shown in FIG. 29B(a), the outer holding member 1066 and the lower light transparent member 1062 are integrally (adhered) in advance. Then, the user places the spacer 1056 on the lower light transparent member 1062.

[0419] Next, as shown in FIG. 29B(b), the user places the excess substance absorption member 1068 outside the spacer 1056 (inside the outer holding member 1066). FIG. 29B(c) shows a state where the spacer 1056 is placed on the lower light transmissive member 1062 and the excess substance absorption member 1068 is installed on the inner upper surface of the outer holding member 1066.

[0420] When the measurement object 22 is solid, the measurement object 22 is pinched with tweezers or the like and installed inside the spacer 1056. FIG. 29B(d) shows an example of the installation method when the measurement object 22 is in a liquid state. In this case, an appropriate amount of the measurement object 22 is injected inside the spacer 1056 with a pipette or a syringe needle.

[0421] When the measurement object 22 is filled inside the spacer 1056, gently place the upper light transmission member 1064 from above. At this time, the surplus substance absorption member 1068 absorbs the surplus liquid that has overflowed from the gap between the spacer 1056 and the upper light transmission member 1064. Due to the surplus liquid absorption effect of this surplus substance absorption member 1068, it prevents the deterioration of measurement accuracy caused by the surplus liquid mixing into the light propagation path 6.

[0422] When measuring using the transmitted light to the measurement object 22, it is desirable to use the holding container structure example in Fig. 29A. In contrast, Fig. 29C shows an example of the holding container structure when measuring using the reflected light from the measurement object 22. In Figs. 29C(a) and (b), instead of using the lower light transmission member 1062 used in Figs. 29A(a) and (b), a light reflection member 1070 with a light reflection film coated on the upper surface (upper single surface) is used. Otherwise, it is all the same as Figs. 29A(a) and (b).

[0423] In Fig. 29A(c), the upper and lower surfaces of the predetermined thickness light transmission member 1054 have light transmission characteristics, and the light used for measurement passes through the upper and lower surfaces of the predetermined thickness light transmission member 1054. In comparison, in Fig. 29C(c), the upper surface of the predetermined thickness light transmission member 1054 is the light reflection surface 1072. Also, the thickness of the predetermined thickness light transmission member 1054 in Fig. 29C(c) matches the thickness t2 of the upper light transmission member 1064.

[0424] When explaining the disturbance noise reduction countermeasure method 1038 using Fig. 26C in Chapter 10, it was explained that the causes of slight disturbance noise generation in the measurement target area 1032 are different. In relation to the content of that explanation, an explanation will be given of an example of a measurement optical system used for comprehensively measuring the overall characteristics of the measurement object 22 and an example of a measurement optical system suitable for measuring the characteristics of only a local area within the measurement object 22.

[0425] FIG. 30A shows an example of a measurement optical system suitable for comprehensive measurement of the overall characteristics of the object to be measured 22. When measuring the characteristics of the entire object to be measured 22, it is desirable to collect and measure the entire detection light 1100 obtained from the entire object to be measured 22. As a specific example, in FIG. 30A, the initial incident light 1200 emitted from the light source unit 2 is uniformly irradiated onto the entire object to be measured 22, and the detection light 1100 obtained from the entire object to be measured 22 is collected and sent to the measurement unit 8. As a method for collecting the detection light 1100, in the embodiment shown in FIG. 30A, the light obtained from the entire object to be measured 22 is condensed by the condenser lens 314 onto the entrance surface of the optical fiber 330.

[0426] As a method for uniformly irradiating the entire object to be measured 22 with the initial incident light 1200 emitted from the light source unit 2, in FIG. 30A, a Köhler illumination system is used. For example, the initial incident light 1200 generated in the light source unit 2 having an optical system structure as shown in FIG. 16 is guided by the optical fiber 330 into the light propagation path 6 including the object to be measured 22. The divergent light (initial incident light 1200) emitted from this optical fiber 330 is converted into parallel light by the collimating lens 318. By setting the size (beam diameter) of this parallel light beam (initial incident light 1200) to be larger than the size of the entire object to be measured 22, a relatively uniform light amount can be irradiated onto the object to be measured 22. Thus, Köhler illumination is suitable for measuring the characteristics of the entire object to be measured 22.

[0427] When using the holding container 1080 for the object to be measured shown in FIG. 29A or FIG. 29B as a method for installing the object to be measured 22 in the light propagation path 6, the convenience for the user is improved. When measuring the optical characteristics of the object to be measured 22 with high precision, if fingerprints or dirt of the user adhere to the surface of the object to be measured 22, the measurement accuracy deteriorates. Since the object to be measured 22 itself is housed inside the holding container 1080 for the object to be measured as shown in FIG. 29A or FIG. 29B, the user does not directly touch the object to be measured 22 before and after measurement. Also, the outer peripheral portion of the outer holding member 1066 that the user directly touches exists outside the light propagation path 6. Therefore, the risk of deterioration of the measurement accuracy due to the handling of the holding container 1080 for the object to be measured can be avoided.

[0428] As an application example of FIG. 30A, an element (e.g., a diffuser) for converting the phase characteristics of the initial incident light 1200 may be disposed in the path of the parallel light beam (initial incident light 1200) immediately before passing through the holding container 1080 of the object to be measured, thereby reducing the degree of temporal coherence of the initial incident light 1200 itself. Based on this, a countermeasure L2 against the optical interference noise generated by the optical interference αc2 in the middle of the optical propagation path 6 can be achieved.

[0429] Furthermore, as another application example of FIG. 30A, an aperture limiting portion 484 (e.g., an aperture, etc.) may be disposed in the path of the parallel light beam (initial incident light 1200) before passing through the holding container 1080 of the object to be measured. By applying such an aperture limitation so that the initial incident light 1200 passes only through the measurement object installation area 1052 in the holding container 1080 of the object to be measured, the stray light mixture αc1 generated during measurement can be prevented.

[0430] Next, a description will be given of an example of a measurement optical system suitable for measuring the characteristics of only a local area within the object to be measured 22. In many cases, for measuring the characteristics of only a local area within the object to be measured 22, an imaging pattern for the object to be measured 22 is formed on the surface of the image sensor 300 using the imaging lens 312.

[0431] FIG. 30B(a) shows an example of an imaging optical system. The detection light 1100 emitted from the β point within the object to be measured 22 is focused on the ε point on the surface of the image sensor 300 under the action of the imaging lens 312 disposed in the middle of the optical path. Similarly, the detection light 1100 emitted from the α point and the γ point within the object to be measured 22 is imaged on the ζ point and the δ point on the surface of the image sensor 300. Therefore, by individually measuring the optical characteristics at each point δ, ε, ζ on the surface of the image sensor 300, it becomes possible to measure the characteristics of each local area γ, β, α within the object to be measured 22. By using the imaging optical system shown in FIG. 30B(a) in this way, it becomes possible to easily measure the optical characteristics regarding the two-dimensionally arranged local areas α, β, γ within the object to be measured 22.

[0432] However, when measuring the optical properties for each local region within the three-dimensional structure of the measurement object 22, or when there is a light scatterer in the optical path of the detection light 1100 from a local region to the measurement unit 8 (e.g., the imaging device 300), in the imaging optical system of FIG. 30B(a), the measurement accuracy deteriorates significantly due to the influence of stray light mixing αc1. Here, as an example where there is a light scatterer in the optical path of the detection light 1100, the case of measuring the neural cell activity in the brain by an optical method can be cited. The brains of higher animals from reptiles onwards are covered by the skull. Since the inside of this skull has a relatively complex structure, it acts as a light scatterer.

[0433] The reason for the deterioration of the measurement accuracy due to the light mixing αc1 will be explained below. FIG. 30B(b) shows the optical path of the detection light 1100 after passing through the imaging lens 312, which exits from the η point closer to the imaging lens 312 than the α point, β point, and γ point arranged in a plane within the measurement object 22 described above. Since the detection light 1100 exiting from the η point spreads on the surface of the imaging device 300, the influence on the δ point, ε point, and ζ point on the surface of the imaging device 300 is relatively minor.

[0434] FIG. 30B(c) shows the optical path of the detection light 1100 after passing through the imaging lens 312, which exits from the ξ point farther from the imaging lens 312 than the α point, β point, and γ point arranged in a plane within the measurement object 22 described above. Since the detection light 1100 exiting from the ξ point converges immediately before the imaging device 300, it irradiates the periphery of the ε point. Therefore, the detection light 1100 exiting from the ξ point mixes into the stray light αc1, deteriorating the measurement accuracy for the measurement object β point. For similar reasons, when there is a light scatterer in the optical path of the detection light 1100, a large amount of stray light mixing αc1 also occurs for the measurement of the optical properties of the local measurement target point β within the measurement object 22.

[0435] FIG. 30C shows an example of a measurement optical system suitable for high-precision measurement in a local region including a three-dimensional field of view within the object 22 to be measured. In the measurement unit 8, an imaging (confocal) optical system is formed for the measurement target position 1086 in the local three-dimensional direction within the object 22 to be measured. Then, an aperture limiting portion 484 is provided at the imaging position or the confocal position corresponding to the measurement target position 1086. And stray light mixing αc1 from different depth positions η, ξ is removed. As a specific example of the form of this aperture limiting portion 484, a pinhole 1088 or a slit 350 may be used.

[0436] In the embodiment example of FIG. 30C, the detection light 1100 in a diverging light state that has passed through the pinhole 1088 or the slit 350 (aperture limiting portion 484) is incident on a spectroscopic element (for example, a blazed grating) 320 in a state of being once converted into parallel light by the collimating lens 318. The detection light 1100 divided for each measurement wavelength by this spectroscopic element is condensed onto the imaging device 300 by the condenser lens 314-2.

[0437] When the pinhole 1088 is used as the aperture limiting portion 484, the imaging device 300 is composed of a one-dimensional arrayed line sensor. And the intensity of the detection light 110 spectroscopically divided for each cell on the line sensor is measured. The spectroscopic signal obtained from this line sensor (imaging device 300) is measured by the signal receiving unit 40 and transferred to the signal processing unit 42.

[0438] On the other hand, when the slit 350 is used as the aperture limiting portion 484, the detection light 1100 emitted from a plurality of local measurement target positions 1086 (for example, the α point to γ point positions in FIG. 30B) arranged in a row on the same plane within the object 22 to be measured simultaneously passes through the slit 350. In the drawing of FIG. 30C in this case, a plurality of local measurement target positions 1086 arranged in a row on the same plane within the object 22 to be measured are projected in the vertical direction within the imaging device 300, and the spectroscopic characteristics for each local measurement target position 1086 (for example, the spectroscopic characteristics for each of the α point, β point, and γ point in FIG. 30B) are measured in the horizontal direction within the imaging device 300.

[0439] The detection light 1100 in a divergent light state from the measurement target position 1086 within the measurement object 22 becomes parallel light by the objective lens 1090. This parallel light detection light 1100 is reflected by the polygon mirror 1082 and the galvano mirror 1084 respectively, and then imaged by the converging lens 314-1.

[0440] In the embodiment of FIG. 30C, the measurement target position 1086 coincides with the front focal position of the objective lens 1090. Therefore, when the distance between the objective lens 1090 and the measurement object 22 is changed, the measurement target position 1086 in the Z direction changes. Also, the inclination angle of the light reflecting surface of the galvano mirror 1084 changes the measurement target position 1086 in the Y direction. And further, the rotation of the polygon mirror 1082 changes the measurement target position 1086 in the X direction. In this way, it becomes possible to measure the spectroscopic characteristics at an arbitrary local measurement target position 1086 in the three-dimensional direction within the measurement object 22.

[0441] For example, an example of measuring the change in spectroscopic characteristics for each local position in the brain in relation to the biological activity in the brain of higher animals from reptiles and later will be described. The detection light 1100 measured by the measurement unit 8 needs to pass through the skull for measurement. The inside of the skull has a relatively complex structure and acts as a light scatterer for the detection light 1100. Also, the scattering angle range of the detection light scattered within the light scatterer is very wide. Therefore, the detection light 1100 after passing through the light scatterer is a mixture of light obtained from different multiple locations and acts as the stray light mixture αc1.

[0442] As a characteristic of the light passing through the light scatterer, a part of the light passing through the light scatterer travels straight through the light scatterer. Therefore, if only the detection light 1100 traveling straight through the light scatterer can be collected and measured, it becomes possible to measure through the light scatterer. Specifically, when using a detection optical system such as FIG. 30C that provides an aperture limiting part 484 at the imaging (confocal) position to measure the optical characteristics of a local measurement target position 1088 within the measurement object 22, the stray light contamination αc1 from other positions within the measurement object 22 can be reduced.

[0443] The most significant cause of the reduction in the amount of light traveling straight through this light scatterer is the "cancellation phenomenon of the amount of straight-through light based on the phase shift between straight-through lights". Here, when the wavelength of the detection light 1100 becomes longer, the influence of the cancellation phenomenon for the same amount of phase shift becomes smaller, and the measurement accuracy through the light scatterer improves. Therefore, near-infrared light with a wavelength of 750 nm or more has less reduction in the amount of light traveling straight through the scatterer than visible light with a wavelength of 700 nm or less. On the other hand, a large amount of cerebrospinal fluid exists directly under the skull. The water component in this cerebrospinal fluid strongly absorbs infrared light with a wavelength of 2 μm or more. Therefore, when measuring the spectral characteristic changes for each local position within the brain through the skull, the measurement accuracy improves when using near-infrared light with a wavelength range of 750 nm to 2 μm (preferably 850 nm to 1.85 μm).

[0444] In the case of measuring an animal or the like as the measurement object 22 in this embodiment example, for example, the measurement system shown in FIG. 20A may be used. Alternatively, at least a part of the measurement object 22 (the part including the measurement target position 1086) may be fixed by some method. On the other hand, when the form of the measurement object 22 is a relatively small solid, or is contained in a liquid or gas, it may be held and measured in the holding container 1080 of the measurement object described with reference to FIGS. 29A to 29C.

[0445] Chapter 14 Optical Disturbance Noise Reduction Method Using Extracted Information As already described with reference to FIG. 26C, the cause 1036 of optical disturbance noise slightly differs depending on the measurement target area 1032. Taking this into account, in Chapter 13, measurement optical system examples suitable for each measurement target area 1032 were described. Also, prior to Chapter 12, the causes of optical interference noise and countermeasure examples thereof were described. In this chapter, examples of methods for reducing the influence of optical disturbance noise by methods other than the above optical interference noise reduction will be described. Specifically, as already described with reference to FIG. 26A, the disturbance noise is reduced using the first extracted information, and the second information extraction 1000 is performed. Based on this, high-precision measurement becomes possible. Note that as the measurement optical system and the holding method of the measurement object 22 used in this chapter, the embodiment examples already described in Chapter 13 may be used.

[0446] FIG. 31A shows various forms of optical disturbance noise generated by the interaction of light inside the measurement object 22. Various interactions occur when the initial incident light 1200 is inside the measurement object 22. Then, the influence of each of these interactions appears in the detection light 1100 obtained from the measurement object 22. That is, the influence of each interaction is mixed into the detection light 1100 as optical disturbance noise.

[0447] First, the case where the measurement object 22 has a complex composition will be described. For example, many biological systems are composed of carbohydrates, lipids, proteins, and nucleotides, and contain a large amount of water. Therefore, for example, even if an attempt is made to measure only the optical properties of proteins in a living body, the influence of the optical properties of water is mixed into the measurement data.

[0448] Infrared spectroscopy, near-infrared spectroscopy, Raman spectroscopy, fluorescence / phosphorescence spectroscopy, etc. perform compositional analysis using the light absorption amount (absorbance) characteristics of light with a specific wavelength inside the measurement object 22. Therefore, the influence of the light absorption αa1 of other components is mixed as optical disturbance noise.

[0449] FIG. 31A(a) shows the influence of the light absorption αa1 of other components when attempting to measure the light absorption characteristics for each wavelength of only the component ζ1096 within the object 22 to be measured. For example, consider a case where the absorbance of the specific wavelength light of the component ζ1096 to be measured is low (almost no light absorption), while the absorbance of the same specific wavelength light is high (a large amount of light absorption) for another component ξ1092. When the initial incident light 1200 with the specific wavelength light is irradiated, a large amount of the specific wavelength light is absorbed within the other component ξ1096 in the object 22 to be measured. Therefore, the intensity of the specific wavelength light contained in the detection light 1100 obtained from the object 22 to be measured significantly decreases.

[0450] The right side of FIG. 31A(b) shows the influence of an example of the light scattering characteristic αa2 of the light transmitted through the component ζ1092. The physical wavelength of light is inversely proportional to the refractive index within the medium through which the light passes. And depending on the refractive index inside the component ζ1092, the physical wavelengths of the light passing through the inside and outside of the component ζ1092 are different. Therefore, when a phase difference occurs between the light passing through the inside of the component ζ1092 and the light traveling straight outside the component ζ1092, they interfere with each other and the amount of light traveling straight decreases. This phenomenon occurs not only when the component ζ1092 exists alone in the air but also when the component ζ1092 is dispersed in an aqueous solution.

[0451] The left side of FIG. 31A(b) shows the influence of the light diffraction and light interference αb2 that occurs when the surface of the component ζ1092 has minute uneven shapes. When the phases of the light passing through the convex part μ and the concave part κ on the surface of the component ζ1092 change with respect to each other, they interfere with each other and the amount of light traveling straight decreases.

[0452] FIG. 31A(c) shows an example of the influence of the light reflection characteristic and the light interference characteristic αa3. For example, consider a case where the upper surface σ and the lower surfaces ν, ω of the component ξ1096 are flat and are in a parallel relationship with each other. Most of the light passing through the inside of the component ξ1096 passes through the lower surface ν. However, a part of the light is reflected by the lower surface ν and returns to the inside of the component ξ. Then, after being reflected by the upper surface σ of the component ξ1096, it exits the component ξ1096 via the lower surface ω. Then, light interference occurs between the light passing through the lower surface ν and the light passing through the lower surface ω via the upper surface σ, and the substantial amount of light passing through changes.

[0453] Figure 31A(d) shows the influence of another example of the light scattering αa2 by the component η1098 included in the object to be measured 22. When the light scattering αa2 occurs with the component η1098, the amount of the directly transmitted light decreases. On the other hand, most of the light bends in a direction greatly deviating from the incident direction of the initial incident light 1200 and the light travels. Thus, various optical interactions occur inside the object to be measured 22.

[0454] In Figure 31A(a), it is affected by the light absorption of the other component ξ1096. However, in the influence of Figure 31A(b) to (d) other than that, although the amount of the direct light traveling in the same direction as the initial incident light 1200 in the detection light 1100 decreases, the light absorption phenomenon does not occur. Therefore, this decrease in the amount of the direct light can be called "light quantity attenuation". Further, the spectral characteristics or the spectral characteristic signal of the detection light 1100 obtained by this phenomenon can also be called the light quantity attenuation spectral characteristics or the light quantity attenuation spectral characteristic signal.

[0455] The relationship with the optical disturbance noise reduction method described in Figure 26A when the various optical interactions shown here occur will be described. First, an example in which the inside of the object to be measured 22 is composed only of the component ξ1096 and the component ζ1092 as shown in Figure 31A(a) will be taken to explain the relationship with Figure 26A.

[0456] In this case, the spectral characteristic information obtained from the other component ξ1096 (absorbance information of the other component ξ1096 alone) is used as the first extracted information 1004. Specifically, the spectral characteristic signal of the detection light 1100 obtained from the measurement object 22 composed only of the constituent component ξ1096 is collected in advance, and the absorbance information (or absorptance information) of the other component ξ1096 alone is extracted 1004 by the signal processing unit 42. Then, using this first extracted information (absorbance information of the other component ξ1096 alone), the absorbance information (or absorptance information) of the constituent component ζ1092 corresponding to the unknown second information is extracted 1000. Specifically, the spectral characteristic signal of the detection light 1100 obtained from the measurement object 22 containing both the constituent component ξ1096 and the constituent component ζ1092 is collected in the measurement unit 8. Then, the signal processing unit 42 subtracts the known absorbance information or absorptance information (first extracted information) of the other component ξ1096 alone from the spectral characteristic signal containing both the constituent component ξ1096 and the constituent component ζ1092, and extracts 1000 the absorbance information or absorptance information (second extracted information 1004) of only the constituent component ζ1092.

[0457] Next, a method for extracting 1000 the absorbance information or absorptance information (second extracted information 1004) of only the constituent component ζ1092 will be described in detail. The spectral characteristic signal obtained by subtracting the known absorbance information or absorptance information (first extracted information) of the other component ξ1096 alone from the spectral characteristic signal containing both the constituent component ξ1096 and the constituent component ζ1092 contains the influence of the interactions in FIGS. 31A(b) to (d). Therefore, in this exemplary embodiment, it is necessary to sequentially remove the influence of the interactions in FIGS. 31A(b) to (d) from the above spectral characteristic signal and extract 1000 the absorbance information or absorptance information (second extracted information 1004) of only the constituent component ζ1092.

[0458] By the way, it is difficult to individually measure the degree of influence of the interactions in FIGS. 31A(b) to (d). Therefore, in this embodiment, signal optimization processing is performed on the spectroscopic characteristic signals, and a correction curve in which the influence of the interactions in FIGS. 31A(b) to (d) is mixed is automatically extracted. This correction curve extracts information 1004 from the spectroscopic characteristic signals including the influence of the interactions in FIGS. 31A(b) to (d). The signal processing unit 42 performs the information extraction 1004 process of this correction curve. In this signal processing (data processing) step, the information of the correction curve in which the influence of the interactions in FIGS. 31A(b) to (d) is mixed corresponds to new first extraction information 1004. Then, the above correction curve information (first extraction information) is deleted from the spectroscopic characteristic signals in a state where the influence of the interactions in FIGS. 31A(b) to (d) is mixed, and the absorbance or absorptivity characteristic information of the component ζ1092 alone with high measurement accuracy is extracted. This signal processing (data processing) step itself corresponds to a process 1000 that uses the first extraction information (correction curve information) to reduce the optical disturbance noise generated by the interactions in FIGS. 31A(b) to (d) and performs second information extraction (extracts the absorbance characteristic information of the component ζ1092 alone with high measurement accuracy).

[0459] The way in which the influence of the interactions in FIGS. 31A(b) to (d) appears in the spectroscopic characteristic signal obtained by subtracting the absorbance information or absorptivity information (first extraction information) of the known other component ξ1096 alone from the spectroscopic characteristic signal including both the component ξ1096 and the component ζ1092 mainly appears in the profile change of the baseline in the spectroscopic characteristic signal. Therefore, the optical disturbance noise reduction process using the correction curve information performed in this embodiment may be called by another name "baseline correction".

[0460] In the above description, for the sake of convenience of explanation, an embodiment in which baseline correction is performed after removing the influence of the absorbance (absorptivity) information 1004 of the other component ξ1096 has been described. However, it is not limited thereto. For example, when the measurement object 22 is composed only of the component ζ1092, baseline correction may be directly performed on the spectroscopic characteristic signal obtained from the measurement unit 8 (and the signal reception unit 40).

[0461] FIG. 31B shows the relationship between the absorbance (or absorptance) characteristic information obtained when using near-infrared light with a wavelength range of 750 nm to 2 μm (preferably 850 nm to 1.85 μm) and the measurement object. The first overtone region, combination tone region, and second overtone region for the vibration mode 982 of the functional group (atomic group) containing hydrogen atoms that make up the molecule absorb the above near-infrared light.

[0462] The first overtone region of the functional group containing hydrogen atoms that make up the molecule mainly absorbs light in the range of 1.37 μm to 1.8 μm with a wavelength of 980. Compared with the combination tone region and the second overtone region, the amount of light absorption here is relatively large. Furthermore, the wavelength range absorbed by each biological system component 988 is different, and the corresponding biological system component 988 can be predicted from the value of the wavelength (center wavelength of the absorption band) that...

Claims

1. A light source unit including a light emitting part, an optical property conversion element, and a condenser lens, wherein the light emitting part emits initial light, the optical property conversion element divides the initial light into a first light and a second light, generates an optical path length difference exceeding an interference distance between the first light and the second light, the condenser lens condenses the first light and the second light with the optical path length difference generated therebetween, a phase property conversion element is disposed at or near the location where the condensing is performed, and the phase property conversion element synthesizes the first light and the second light to generate predetermined light.

2. A method for generating predetermined light, comprising dividing initial light emitted by a light emitting part into a first light and a second light, generating an optical path length difference exceeding an interference distance between the first light and the second light, condensing the first light and the second light with the optical path length difference generated therebetween, and synthesizing the first light and the second light by a phase property conversion element disposed at or near the location where the condensing is performed to generate predetermined light.

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