Light guidance device and camera module comprising same

Abstract

Disclosed is a camera module according to an embodiment comprising: a light guidance device for guiding light and irradiating an object with same, and guiding the light reflected from the object; and a light-receiving unit for receiving the light reflected and guided from the object, wherein the light guidance device comprises a substrate, and input and output diffraction elements distanced from each other on the substrate, the substrate being perpendicular to a first direction, and the minimum separation distance between the input and output diffraction elements in a second direction perpendicular to the first direction being proportional to the width, in the first direction, of the substrate and the diffraction angle, in the first direction, of the input diffraction element.

Description

Light guide device and camera module including the same

[0001] The embodiment relates to a light guide device and a camera module including the same.

[0002] Currently, traffic accidents caused by drivers are increasing significantly along with the increase in the number of vehicles, and there is a problem in that the incidence rate of these accidents increases significantly depending on the driver's physical condition.

[0003] In particular, accidents caused by driver inattention, such as the use of smartphones while driving, have been increasing significantly recently. Due to the rising problem of traffic accidents resulting from such driver inattention or drowsy driving, automobile manufacturers are now equipping vehicles with Driver Monitoring Systems (DMS) that monitor the driver's concentration and physical condition while driving.

[0004] While DMS was generally implemented at the level of simply predicting the driver's condition based on the driver's steering state or the driving time and raising the driver's awareness through warning sounds or messages, recently, with the development of Advanced Driver Assistance Systems (ADAS) that provide various functions to directly assist the driver, such as Adaptive Cruise Control (ACC), which drives while maintaining a distance from the vehicle in front at a speed set by the driver, and Lane Keeping Assist System (LKAS), which recognizes lanes using a camera to maintain the lane, various methods are being implemented to more actively identify the driver's state of concentration or physical condition such as drowsiness. These methods include monitoring the driver's physical movements through video captured by a camera or monitoring the movement of the driver's eyelids to determine whether the driver is drowsy or focused on driving, and generating steering wheel vibrations or warning sounds to the driver or reducing the vehicle's speed to below a certain level to avoid danger.

[0005] Meanwhile, as the autonomous driving performance of automobiles advances, drivers no longer necessarily need to hold the steering wheel, and as hands-off situations occur frequently, there is a demand for a driver monitoring system equipped with a hands-off monitoring function. Consequently, there is a need for an advanced DMS capable of determining the driver's state of concentration or drowsiness based on various driver movements resulting from hands-off.

[0006] However, as drivers and others do not prefer to be filmed or monitored, there is an increasing need for technology that prevents drivers from being aware of such surveillance.

[0007] The embodiment provides a light guide device and a camera module that facilitate the creation of images of occupants, etc., within a vehicle.

[0008] In addition, the embodiment provides a light guide device and camera module that are easy to manufacture and miniaturized.

[0009] The problem to be solved in the embodiments is not limited thereto, and may also include objectives or effects that can be identified from the means of solving the problem or the forms of implementation described below.

[0010] A camera module according to an embodiment includes a light guide device that guides light to irradiate an object and guides light reflected from the object; and a light receiving unit that receives light reflected from the object and guided. The light guide device includes a substrate, an incident diffraction element and an output diffraction element spaced apart from each other on the substrate, wherein the substrate is arranged perpendicular to a first direction, and the minimum separation distance in a second direction perpendicular to the first direction of the incident diffraction element and the output diffraction element may be proportional to the width of the substrate in the first direction and the diffraction angle in the first direction of the incident diffraction element.

[0011] The minimum separation distance in the second direction between the incident diffraction element and the output diffraction element can be determined by Equation 1.

[0012] [Mathematical Formula 1]

[0013]

[0014] (here, min d (IC- OC ) is the minimum separation distance in the second direction between the incident diffraction element and the output diffraction element, t is the width in the first direction of the substrate, and θ d is the diffraction angle in the first direction of the input diffraction element)

[0015] The diffraction angle in the first direction of the input diffraction element may be the angle formed with the first direction after the light passes through the input diffraction element.

[0016] The output diffraction element includes a first region that overlaps with the light receiving part in the first direction and a second region that does not overlap, and the minimum width in the second direction of the output diffraction element can be determined by the difference in width between the first region and the second region in the second direction.

[0017] The minimum width in the second direction of the output diffraction element can be determined by Equation 2.

[0018] [Mathematical Formula 2]

[0019]

[0020] (Here, OC xmin is the minimum width in the second direction of the output diffraction element, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x is the angle of view in the second direction of the light receiver, and x is the width in the second direction of the light receiver)

[0021] The maximum width in the second direction of the output diffraction element can be determined by Equation 3.

[0022] [Mathematical Formula 3]

[0023]

[0024] (Here, OC xmax is the maximum width in the second direction of the output diffraction element, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x is the angle of view in the second direction of the light receiver, x is the width in the second direction of the light receiver, and dx is the allowable width of the light receiver.

[0025] The minimum separation distance in the second direction between the incident diffraction element and the center of the light receiving part can be determined by Equation 4.

[0026] [Mathematical Formula 4]

[0027]

[0028] (Here, minD is the minimum separation distance in the second direction between the center of the incident diffraction element and the light receiver, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x is the angle of view in the second direction of the light-receiving part, x is the width in the second direction of the light-receiving part, t is the width in the first direction of the substrate, and θd is the diffraction angle in the first direction of the input diffraction element)

[0029] The minimum width in the third direction perpendicular to the first direction and the second direction of the incident diffraction element may be proportional to the separation distance in the second direction of the incident diffraction element and the output diffraction element.

[0030] The minimum width in the third direction of the incident diffraction element can be determined by Equation 5.

[0031] [Mathematical Formula 5]

[0032]

[0033] (Here, minIC y is the minimum width in the third direction of the incident diffraction element, and d (IC- OC ) is the separation distance between the incident diffraction element and the output diffraction element in the second direction, and φ2 is the diffraction angle in the third direction of the input diffraction element.

[0034] The diffraction angle in the third direction of the input diffraction element may be the angle formed with the second direction on a plane perpendicular to the first direction after the light passes through the input diffraction element.

[0035] The substrate includes a first surface and a second surface spaced apart from the first surface, and the incident diffraction element may be disposed on the first surface and the output diffraction element may be disposed on the second surface.

[0036] The incident diffraction element and the output diffraction element may not overlap each other in the first direction.

[0037] The second direction above may be the shortest distance direction between the incident diffraction element and the output diffraction element.

[0038] According to an embodiment, a light guide device and a camera module can be provided that facilitate the creation of images of occupants, etc., within a vehicle.

[0039] In addition, it is possible to provide light guide devices and camera modules that are easy to manufacture and miniaturized.

[0040] The various and beneficial advantages and effects of the present invention are not limited to those described above and may be more easily understood in the process of explaining specific embodiments of the present invention.

[0041] FIG. 1 is a conceptual diagram of a vehicle including a camera module according to an embodiment of the present invention, and

[0042] FIG. 2 is a drawing illustrating the operation according to a camera module according to an embodiment of the present invention, and

[0043] FIG. 3 is a flowchart illustrating the operation of a camera module according to an embodiment, and

[0044] FIG. 4 is a block diagram of a camera module according to an embodiment, and

[0045] FIG. 5 is a drawing showing the configuration of a camera module according to an embodiment, and

[0046] FIG. 6 is a diagram illustrating the operation of a camera module according to an embodiment, and

[0047] FIGS. 7 and 8 are drawings showing the propagation path of light in a light guide device of a camera module according to an embodiment, and

[0048] FIG. 9 is a schematic diagram of a light guide device of a camera module according to an embodiment, and

[0049] FIGS. 10 to 12 are reference drawings for explaining a light guide device of a camera module according to an embodiment.

[0050] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0051] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0052] In addition, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0053] Furthermore, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0054] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0055] In addition, terms such as first, second, A, B, (a), (b), etc. may be used when describing the components of the embodiments of the present invention.

[0056] These terms are intended merely to distinguish a component from other components and are not limited by the nature, order, sequence, etc., of the said component.

[0057] And, where it is stated that a component is 'connected', 'combined', or 'joined' to another component, this may include not only cases where the component is directly connected, combined, or joined to the other component, but also cases where it is 'connected', 'combined', or 'joined' due to another component located between the component and the other component.

[0058] Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0059] FIG. 1 is a conceptual diagram of a vehicle including a camera module according to an embodiment of the present invention, FIG. 2 is a diagram explaining the operation according to a camera module according to an embodiment of the present invention, and FIG. 3 is a flowchart explaining the operation of a camera module according to an embodiment.

[0060] Referring to FIG. 1, a vehicle system (or environment) according to an embodiment may include a vehicle (1), a passenger (driver), and an electronic device (CU). In the following description, the electronic device (CU) is described as a device separately provided within the vehicle (1), but the present invention is not limited thereto. For example, the electronic device (CU) may be implemented as a part of the vehicle (1).

[0061] The vehicle (1) may include a vehicle body and various devices for moving the vehicle body (e.g., wheels, a drive unit for driving the wheels, a starter unit for starting the drive unit, an engine that generates power and transmits the generated power to the drive unit, a steering unit that controls the direction of the vehicle, an acceleration unit that controls the speed of the vehicle, etc.). In addition, the vehicle (1) may include various electrical systems. For example, the electrical systems may include an engine control unit that controls the engine, a temperature control unit that controls the temperature inside the vehicle, a light control unit that controls the lights according to external conditions, etc.

[0062] In particular, the vehicle (1) may include a communication interface capable of communicating with an electronic device (CU), and may include an additional processor that performs a preset function based on the analysis of data transmitted through the communication interface and the results of the analysis.

[0063] The processor may be implemented, for example, as the engine control unit or motor control unit described above. The communication interface may support at least one of various communication methods, such as CAN communication that supports data transmission and reception within the vehicle (1) or wired communication through a cable connected to an electronic device (CU). As an example, the vehicle (1) may receive an image or an analysis result of the image acquired by the electronic device (CU) and perform a designated function according to the received result.

[0064] According to an embodiment, an electronic device (CU) is connected to a camera module (100) to perform image acquisition of a driver and, after performing analysis on the acquired image, can perform various set function processing (e.g., deceleration processing, hazard light turn-on or turn-off, horn device control, vehicle vibration control, window opening / closing control, etc.) according to the analysis result. In addition, various additional function processing may be implemented in addition to these function processing.

[0065] The driver, as a person capable of controlling the steering device while seated in the driver's seat, can be the subject of image capture by an electronic device (CU). In the present invention, the electronic device (CU) acquiring an image of the driver seated in the driver's seat is described as a representative example, but the present invention is not limited thereto. For example, the monitoring system may be applied to acquire images of not only the driver but also a passenger seated in the auxiliary seat or other seats, and to control the image acquisition method according to various actions of the passenger. In this regard, at least one electronic device (CU) may be installed in the vehicle (1). For example, a camera module (100) and an electronic device (CU) may be installed to acquire an image of the driver seated in the driver's seat, which supports only driver monitoring.

[0066] Alternatively, if a monitoring function for the driver and passenger is supported, a plurality of electronic devices (CU) may be placed in the vehicle (1) to enable image acquisition of the driver's seat and passenger seats.

[0067] Referring further to FIG. 2, an electronic device (CU) can receive image information regarding the driver's face (A2) via a camera module (100). Accordingly, the electronic device (CU) can determine the driver's drowsiness in a predetermined manner and provide various feedback (e.g., alarms) corresponding thereto. For example, the electronic device (CU) can determine whether the driver is drowsy based on the user's eye track, iris size, or changes in size. In addition, the electronic device (CU) can receive image information regarding the driver's hands (A1, A3) as well as the user's face (A2) from the camera module (100). Accordingly, the electronic device (CU) can easily determine the driver's hands-off state. In other words, a driver monitoring system having a hands-off monitoring function can be implemented. As a result, the driver's state of concentration or drowsiness can be easily determined based on various movements of the driver following the driver's hands-off.

[0068] The camera module (100) can be positioned in a location within the vehicle where it can easily photograph the occupant. For example, it can be positioned in various specific locations of the vehicle (1), such as the windshield (e.g., the location where the head-up display is placed), the bottom of the windshield, the dashboard, the instrument panel, etc., so as to acquire an image of a subject seated in the driver's seat. Furthermore, the camera module (100) may be positioned in a location that is difficult for the occupant to easily perceive.

[0069] Additionally, a camera module (100) connected to an electronic device (CU) is positioned at a predetermined location within the vehicle (1) to receive image information regarding passengers other than the driver of the vehicle (1). For example, there may be at least one camera module (100) and it may be positioned in a rearview mirror (or room mirror), etc., to detect all passengers other than the driver. Thus, the camera module (100) can generate an image of all passengers.

[0070] Thus, the camera module (100) can generate image information of other passengers (A5, A6, A7) other than the driver (A4) in the vehicle. And the electronic device (CU) can receive image information including passengers other than the driver. With this configuration, a monitoring system for not only the driver but also other passengers can be easily implemented.

[0071] Referring to FIG. 3, the monitoring method according to the embodiment may include the step of driving a camera device or module (S310), the step of receiving image information (S320), and the step of providing a preset function processing (e.g., alarm, emergency light turn on / off, horn, etc.) by analyzing the image information (S330).

[0072] First, a camera device or module can be operated (S310). The camera module may operate in specific situations or at specific times. For example, the camera module may be operated when the vehicle is moving. When the vehicle is not moving, the camera module may or may not be operated. For example, the operation status of the vehicle may be determined based on whether it is moving or not through navigation, etc., and if the result of the determination is that it is moving, the operation status of the camera module may be determined (e.g., start camera operation when moving).

[0073] The camera module can generate an image of a driver or passenger (S320). As described below, an image of an object or subject can be generated through a light source, a light guide device, a light receiving unit, etc.

[0074] In addition, image information generated from the camera module is analyzed, and pre-set function processing can be provided through the analysis (S330). For example, an electronic device or a control unit can determine whether the driver is drowsy based on changes in the position of feature points on the driver's face in the image information or whether the change persists. For example, the reference position for the change in the position of feature points may correspond to the average value of the driver's eye feature point position over a certain period of time after driving begins. Furthermore, since the monitoring method according to the embodiment can accurately calculate the position and position change of eye feature points by applying depth information, the driver's drowsiness state can be accurately monitored, and thus the reliability of the product can be improved.

[0075] Each of the aforementioned steps can be implemented by an electronic device (CU) or a control unit within a camera module, etc.

[0076] FIG. 4 is a block diagram of a camera module according to an embodiment, FIG. 5 is a diagram showing the configuration of a camera module according to an embodiment, and FIG. 6 is a diagram explaining the operation of a camera module according to an embodiment.

[0077] Referring to FIG. 4, a camera module (100) according to an embodiment may include a light source unit (110), a light guide device (120), a light receiving unit (130), and a control unit (140).

[0078] First, the light source unit (110) can output light by means of a control signal. Finally, the light output from the light source unit (110) can be irradiated onto an object. The light irradiated onto the object can then be reflected and provided to the light receiving unit (130).

[0079] The light source unit (110) may include at least one light source. The at least one light source may emit light of a predetermined wavelength band or light having a predetermined center wavelength. Additionally, the light source of the light source unit (110) may emit light of a predetermined pattern according to a pre-designed algorithm. This light source unit (110) may output light under the control of the control unit (140).

[0080] In the following description, output light or incident light refers to light that is output from the light source unit (110) and provided to an object, and input light or reflected light may refer to light that is output from the light source unit (110), reaches the object, is reflected from the object, and is input to the light receiving unit (130). That is, from the perspective of the object, output light can be incident light, and input light can be reflected light.

[0081] At least one light source of the light source unit (110) can output light of a predetermined wavelength band. For example, the wavelength of the light output from the light source may be infrared light with a wavelength of 770 nm to 3000 nm. In addition, the wavelength of the light output from the light source may be visible light with a wavelength of 380 nm to 770 nm. Furthermore, the light source of the light source unit (110) may emit light other than the aforementioned wavelength range. In particular, as described above, the light source may irradiate light of a specific wavelength band so as not to be harmful to occupants such as the driver and passenger inside the vehicle, or irradiate light of a specific energy or lower so as not to be harmful.

[0082] The light source may include a light-emitting diode (LED), an organic light-emitting diode (OLED), a laser diode (LD), a vertical-cavity surface-emitting laser (VCSEL), a plasma lamp, a fluorescent lamp, a xenon lamp, a halogen lamp, a neon lamp, etc. It may output a wavelength of about 800 nm to 1000 nm, for example, about 850 nm or about 940 nm.

[0083] The light guide device (120) can be positioned adjacent to the light source unit (110) and the light receiving unit (130). The light guide device (120) can guide light irradiated from the light source unit (110) and deliver it to an object. The light guide device (120) can also guide light reflected from the object back to the light receiving unit (130). In this way, the light guide device (120) can be configured to control light and move it along a desired path. In other words, the light guide device (120) can perform both delivering light to an object (O) and receiving reflected light. Accordingly, the light guide device (120) can be configured to help light from the camera module (100) reach the sensor accurately or guide it along a specific path so that optical information is accurately delivered.

[0084] Such light guide devices (120) may be made of materials such as glass, polymer, or silicon. The light guide devices (120) may include various other materials capable of light guiding.

[0085] And the light guide device (120) can transmit light in a desired direction using diffraction. Accordingly, the light guide device (120) may include an optical element for determining the path of light on a substrate that is a waveguide. The optical element may include various elements that operate based on diffraction.

[0086] In an example, the light guide device (120) may include a diffraction element which is a holographic optical element (HOE). The light guide device (120) may include an input diffraction element, an input / output diffraction element, and an output diffraction element as described below. For example, the input diffraction element, the input / output diffraction element, and the output diffraction element may be composed of holographic optical elements.

[0087] Furthermore, holographic optical elements diffract light using interference patterns generated through laser interference, thereby enabling the control of light of specific wavelengths or diffraction in desired directions. Bragg's Law applies during this diffraction process, and the diffraction angle can be determined by the wavelength of the light and the structure of the holographic optical element.

[0088] A holographic optical element can be composed of an interference pattern recorded on a transparent substrate. As previously mentioned, the transparent substrate can be a waveguide and can be made of various materials such as glass, plastic, or polymer. The interference pattern of the holographic optical element can be precisely designed inside or on the surface of the substrate to guide light in a specific direction. Furthermore, holographic optical elements can be classified into a transmissive type, in which light diffracts as it passes through, and a reflective type, in which light diffracts as it is reflected. Accordingly, the position of the holographic optical element on the substrate can change. By precisely controlling light through such a holographic optical element, high-resolution images can be provided. Additionally, the holographic optical element can support high-speed data transmission in optical communication through wavelength separation and combination. Moreover, since the holographic optical element is lighter and thinner than conventional lenses or mirrors, it can provide a miniaturized camera module. A detailed description of the input diffraction element, input / output diffraction element, and output diffraction element, which are diffraction elements in the light guide device (120), will be provided later.

[0089] The light receiving unit (130) can receive light transmitted through the light guide device (120). The light receiving unit (130) may include an image sensor. The image sensor can receive light reflected from an object. Accordingly, the image sensor can detect light and convert it into an electrical signal. For example, the image sensor can generate a digital image by converting the electrical signal. The image sensor may include a Charge-Coupled Device (CCD), a Complementary Metal-Oxide-Semiconductor (CMOS), an InGaAs (Indium Gallium Arsenide) sensor, a Mercury Cadmium Telluride (HgCdTe) sensor, a microbolometer, etc. The light receiving unit (130) may also include an image sensor that receives light of various wavelength bands other than those described above or examples.

[0090] The light receiving unit (130) may also be located adjacent to the light guide device (120), just like the light source unit (110). Alternatively, an additional lens (not shown) may be placed between the light receiving unit (130) and the light guide device (120). This may also be applied equally between the light source unit (110) and the light guide device (120).

[0091] The control unit (140) can control the operation of the light source unit (110) and the light receiving unit (130). The control unit (140) can generate depth information based on an image generated by the light receiving unit (130) or transmit and receive image information with other electronic devices, such as a vehicle. This control unit (140) can control the operation within the camera module and can also communicate with a processor, etc., within an external electronic device, such as a vehicle.

[0092] The control unit (140) may include a processor, a microcontroller (MCU), a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), etc., and may also be implemented in the form of an Application Processor (AP) of various electronic devices.

[0093] Referring to FIGS. 5 and 6, the light guide device (120) may include a substrate (WG), an input diffraction element (121), an input / output diffraction element (122), and an output diffraction element (123).

[0094] The input diffraction element (121), the input / output diffraction element (122), and the output diffraction element (123) may be placed on a substrate (WG) which is a waveguide. The input diffraction element (121), the input / output diffraction element (122), and the output diffraction element (123) correspond to either a light-transmitting type or a reflective type, and may be located on either one side (e.g., the top surface) or the other side (e.g., the bottom surface) of the substrate (WG).

[0095] And the input diffraction element (121), input / output diffraction element (122), and output diffraction element (123) are diffraction elements as described above and can be spaced apart from each other.

[0096] The input diffraction element (121) may be configured such that the incident angle of the optical axis in the light irradiated from the light source unit (110) varies according to the wavelength based on the grating vector of the input diffraction element (121). The input diffraction element (121) may be composed of a plurality of diffraction elements or may include a plurality of regions. In an embodiment, light (L1) emitted from the light source unit (110) is input to the input diffraction element (121), and the input diffraction element (121) may diffract the light irradiated from the light source unit (110) and guide it into the substrate (WG) (L2). The input diffraction element (121) diffracts the light (L1) provided from the light source unit (110) and guides it into the substrate (WG), and the light (L2) guided into the substrate (WG) may be provided to the input / output diffraction element (122).

[0097] The input / output diffraction element (122) can diffract light (L2) guided from the input diffraction element (121) to the substrate (WG) toward the object (O) (L3), and diffract light (L4) reflected from the object (O) toward the substrate (WG) to guide it into the substrate (WG) (L5). Specifically, it can diffract light (L2) guided from the input diffraction element (121) toward the substrate (WG) and guide it toward the object (O). That is, the input / output diffraction element (122) can diffract light toward the object (O) (L3). And the light (L3) emitted from the input / output diffraction element (122) can be reflected from the object (O) and provided to the input / output diffraction element (122) (L4). At this time, the light (L4) provided to the input / output diffraction element (122) can be diffracted at the input / output diffraction element (122) and the light path can be changed. Accordingly, the input / output diffraction element (122) can diffract the light reflected from the object (O) and guide it to the substrate (WG) (L5). At this time, the light (L5) diffracted at the input / output diffraction element (122) and guided to the substrate (WG) can be guided to or provided to the output diffraction element (123).

[0098] The object (O) may be various objects outside the camera module or the light guide device (120). That is, the object (O) is a various object that can be detected or recognized through the camera module, and may include people, cars, animals, buildings, etc. For example, a passenger inside a vehicle or a building or object outside the vehicle may correspond to the object.

[0099] The output diffraction element (123) can diffract light (L5) that is reflected from the object (O) and guided to the substrate (WG) by the input / output diffraction element (122), and guide or provide it to the light receiving unit (130). At this time, the light (L6) that is diffracted from the output diffraction element (123) and guided to the light receiving unit (130) is incident on the light receiving unit (130) and can be converted into image information.

[0100] The camera module according to the present embodiment may consist of an illumination system and an imaging system. The illumination system can perform the role of illuminating a target with light in an optical system. This illumination system can help the target or subject to be seen clearly by uniformly dispersing or concentrating the light. The imaging system can perform the role of forming an image of the target in an optical system. This imaging system can collect light to focus it and form an image on an image sensor, film, or the eye. These illumination and imaging systems work together in an optical system to play an important role in forming an accurate and sharp image.

[0101] The illumination system may consist of components along a path through which light emitted from a light source unit (110) passes through an input diffraction element (121), a substrate (WG), and an input / output diffraction element (122) to be provided to an object (O). The imaging system may consist of components along a path through which light reflected from the object (O) passes through an input / output diffraction element (122), a substrate (WG), and an output diffraction element (123) to be provided to a light receiving unit (130). For example, the illumination system may include a light source unit, an input diffraction element (121), a substrate (WG), and an input / output diffraction element (122). The imaging system may include an input / output diffraction element (122), a substrate (WG), an output diffraction element (123), and a light receiving unit (130). The camera module may include components (e.g., a substrate, an input / output diffraction element) that belong to both the illumination system and the imaging system.

[0102] FIGS. 7 and 8 are diagrams showing the propagation path of light in a light guide device of a camera module according to an embodiment.

[0103] Referring to FIGS. 7 and 8, the path of light can be determined through each diffraction element of the light guide device. The path of light can be determined according to the size, position, or distance between each diffraction element. FIG. 7 shows the propagation path of light for a specific angle of incidence. FIG. 8 shows the position where light is totally reflected within the substrate as a point when the light guide device is viewed in a vertical direction. The position or size of the input / output diffraction elements can be determined through the position where light is totally reflected in FIG. 8. By assuming that light is incident through the output diffraction element and tracing the path of light in reverse, the minimum size of the input / output diffraction elements or the minimum distance between the input / output diffraction elements and the output diffraction elements can be determined. In the camera module according to the embodiment, the size of the output diffraction element can be determined through the size and position of the light receiving part, and the position of total reflection of light and the path of light can be determined through the size and position of the output diffraction element. Since there must be an input / output diffraction element containing at least one point at the point where light of each angle of view propagates, the combined area of ​​the input / output diffraction elements of all angles of view can be determined as the minimum size that the input / output diffraction element must have.

[0104] FIG. 9 is a schematic diagram of a light guide device of a camera module according to an embodiment, and FIGS. 10 to 12 are reference drawings for explaining a light guide device of a camera module according to an embodiment.

[0105] The input / output diffraction elements of FIGS. 5 and 6 may be referred to as incident diffraction elements in FIGS. 9 to 12 below. That is, the incident diffraction elements of FIGS. 9 to 12, which will be described later, may correspond to the input / output diffraction elements of FIGS. 5 and 6 described above.

[0106] Referring to FIG. 9, the camera module (100) may include a light guide device (120) and a light receiving unit (130), and the light guide device (120) may include a substrate (WG), an incident diffraction element (122), and an output diffraction element (123).

[0107] Hereinafter, the first direction may correspond to the Z-axis direction in FIGS. 9 to 12. The second direction is a direction perpendicular to the first direction and may correspond to the X-axis direction in FIGS. 9 to 12. The third direction is a direction perpendicular to the first direction and the second direction and may correspond to the Y-axis direction in FIGS. 9 to 12.

[0108] The light guide device (120) can guide light to illuminate an object and guide light reflected from the object. The light guided by the light guide device (120) can be emitted outward and incident on the light receiving unit (130). The light can be incident on the interior of the light guide device (120) through the incident diffraction element (122), guided through the substrate (WG), and emitted outward through the output diffraction element (123).

[0109] The substrate (WG) may be positioned perpendicular to the first direction. The substrate (WG) may be positioned perpendicular to the first direction to guide light in the second direction. The second direction is a direction perpendicular to the first direction and may be the shortest distance direction when the incident diffraction element (122) and the output diffraction element (123) are viewed in the first direction. The substrate (WG) may include a first surface (s1) and a second surface (s2) spaced apart in the first direction. The first surface (s1) and the second surface (s2) may be positioned parallel to each other. The first surface (s1) and the second surface (s2) may be surfaces on which light is incident or emitted.

[0110] The incident diffraction element (122) and the output diffraction element (123) may be disposed on the substrate (WG). The incident diffraction element (122) and the output diffraction element (123) may be disposed perpendicular to the first direction. The incident diffraction element (122) may be disposed on the first surface (s1) of the substrate (WG). The output diffraction element (123) may be disposed on the second surface (s2) of the substrate (WG). The incident diffraction element (122) and the output diffraction element (123) may be spaced apart by a certain distance in the first direction. Additionally, the incident diffraction element (122) and the output diffraction element (123) may be spaced apart by a certain distance in the second direction. The incident diffraction element (122) and the output diffraction element (123) may have a certain width in the second direction or the third direction. The incident diffraction element (122) and the output diffraction element (123) are placed on different sides of the substrate (WG) and may not overlap each other in the first direction.

[0111] The light receiving unit (130) can receive light emitted from the light guide device (120). The light receiving unit (130) can be positioned spaced apart from the light guide device (120). The light receiving unit (130) can be positioned spaced apart from the light guide device (120) in a first direction. The light receiving unit (130) can be spaced apart from the output diffraction element (123) in a first direction. The light receiving unit (130) can be positioned to overlap with the output diffraction element (123) in a first direction. The light receiving unit (130) can receive light emitted from the output diffraction element (123) by overlapping with the output diffraction element (123) in a first direction.

[0112] The incident diffraction element (122) and the output diffraction element (123) are spaced a certain distance (d) in the second direction. (IC-OC) ) can be separated. The minimum separation distance in the second direction between the incident diffraction element (122) and the output diffraction element (123) is the width (t) in the first direction of the substrate and the diffraction angle (θ) in the first direction of the incident diffraction element. dIt can be proportional to ). The minimum separation distance in the second direction between the incident diffraction element (122) and the output diffraction element (123) may mean the minimum distance that the incident diffraction element (122) and the output diffraction element (123) must be separated in the second direction so that light can reach the light receiving part (130) through the light guide device (120). Width (t) in the first direction of the substrate or diffraction angle (θ) in the first direction of the incident diffraction element d As ) increases, the minimum separation distance in the second direction between the incident diffraction element (122) and the output diffraction element (123) can increase. The diffraction angle (θ) in the first direction of the incident diffraction element d ) may mean the angle formed with the first direction after the light passes through the incident diffraction element (122).

[0113] The minimum separation distance in the second direction between the incident diffraction element (122) and the output diffraction element (123) can be determined by Equation 1.

[0114]

[0115] Here, min d (IC- OC ) is the minimum separation distance in the second direction between the incident diffraction element and the output diffraction element, t is the width in the first direction of the substrate, and θ d The diffraction angle in the first direction of the input diffraction element may be the diffraction angle. By determining the minimum separation distance in the second direction between the incident diffraction element (122) and the output diffraction element (123), the width in the second direction can be minimized while maintaining the performance of the light guide device, thereby achieving miniaturization of the camera module.

[0116] The output diffraction element (123) includes a first region (a1) that overlaps with the light receiving part (130) in a first direction and a second region (a2) that does not overlap, and the minimum width of the output diffraction element (123) in the second direction can be determined by the difference in width between the first region (a1) and the second region (a2) in the second direction. The first region (a1) may be an area of ​​the output diffraction element (123) that overlaps with the light receiving part (130) in a first direction. Additionally, the second region (a2) may be an area of ​​the output diffraction element (123) that does not overlap with the light receiving part (130) in a first direction. The first region (a1) may be located inside the second region (a2). The first region (a1) and the second region (a2) may have a certain width in the first direction. The output diffraction element (123) has a certain width (OC) in the second direction. x It may have ). Depending on the difference in width in the second direction of the first region (a1) and the second region (a2), the minimum width of the output diffraction element (123) in the second direction may vary. That is, the minimum width of the output diffraction element (123) in the second direction may be determined according to the ratio of the area where the output diffraction element (123) and the light receiving part (130) overlap in the first direction. The minimum width of the output diffraction element (123) in the second direction may mean the minimum width at which the output diffraction element (123) must be positioned in the second direction so that light can reach the light receiving part (130) through the light guide device (120) while maintaining the performance of the camera module. Additionally, the maximum width in the second direction of the output diffraction element (123) may mean the maximum width at which the output diffraction element (123) can be positioned in the second direction so that light can reach the light receiving part (130) through the light guide device (120) while maintaining the performance of the camera module.

[0117] A camera module in which the minimum width in the second direction of the output diffraction element (123) is determined by Equation 2.

[0118]

[0119] Here, OC xmin is the minimum width in the second direction of the output diffraction element, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x θ is the angle of view in the second direction of the light receiving part, and x may be the width in the second direction of the light receiving part. By determining the minimum width in the second direction of the output diffraction element (123), the width in the second direction can be minimized while maintaining the performance of the light guide device, thereby achieving miniaturization of the camera module.

[0120] In addition, the maximum width in the second direction of the output diffraction element (123) can be determined by Equation 3.

[0121]

[0122] (Here, OC xmax is the maximum width in the second direction of the output diffraction element, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x θ is the angle of view in the second direction of the light receiving part, x is the width in the second direction of the light receiving part, and dx may be the allowable width of the light receiving part. By determining the maximum width in the second direction of the output diffraction element (123), the width in the second direction of the output diffraction element (123) can be adjusted without reducing the light guiding performance of the light guide device (120).

[0123] The incident diffraction element (122) can be spaced a certain distance (D) in the second direction from the center of the light receiving part (130).

[0124] The minimum separation distance in the second direction of the center of the incident diffraction element (122) and the light receiving part (130) can be determined by Equation 4.

[0125]

[0126] Here, D is the separation distance in the second direction between the center of the incident diffraction element and the light-receiving part, d is the separation distance in the first direction between the output diffraction element and the light-receiving part, and fov xθd may be the angle of view in the second direction of the light receiving part, x may be the width in the second direction of the light receiving part, t may be the width in the first direction of the substrate, and θd may be the diffraction angle in the first direction of the input diffraction element. By determining the minimum separation distance in the second direction between the center of the incident diffraction element (122) and the light receiving part (130), the width in the second direction can be minimized while maintaining the performance of the light guide device, thereby achieving miniaturization of the camera module.

[0127] The incident diffraction element (122) has a constant width (IC) in the third direction. y Can have ).

[0128] The minimum width in the third direction of the incident diffraction element (122) is the separation distance (d) in the second direction between the incident diffraction element (122) and the output diffraction element (123). (IC- OC ) It can be proportional to ). As the distance between the incident diffraction element (122) and the output diffraction element (123) in the second direction increases, the minimum width in the third direction of the incident diffraction element (122) can increase.

[0129] The minimum width in the third direction of the incident diffraction element (122) can be determined by Equation 5.

[0130]

[0131] Here, minICy is the minimum width in the third direction of the incident diffraction element, and d (IC- OC )θ is the distance between the incident diffracting element and the output diffracting element in the second direction, and φ2 may be the diffraction angle in the third direction of the input diffracting element. The diffraction angle (φ2) in the third direction of the incident diffracting element (122) may be the angle formed with the second direction on a plane perpendicular to the first direction after the light passes through the incident diffracting element (122). By determining the minimum width in the third direction of the incident diffracting element (122), the width in the second direction can be minimized while maintaining the performance of the light guide device, thereby achieving miniaturization of the camera module.

[0132] Although the above description has focused on the embodiments, this is merely an example and is not intended to limit the embodiments. A person skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For instance, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the embodiments set forth in the appended claims.

Claims

1. A light guide device that guides light to illuminate an object and guides light reflected from the object; and A light receiving unit that receives light reflected and guided from the above object; The above light guide device is, It includes a substrate, an incident diffraction element and an output diffraction element spaced apart from each other on the substrate, and The above substrate is positioned perpendicular to the first direction, and A camera module in which the minimum separation distance in the second direction perpendicular to the first direction of the incident diffraction element and the output diffraction element is proportional to the width in the first direction of the substrate and the diffraction angle in the first direction of the incident diffraction element.

2. In Paragraph 1, A camera module in which the minimum separation distance in the second direction between the incident diffraction element and the output diffraction element is determined by Equation 1. [Mathematical Formula 1] (here, min d (IC- OC ) is the minimum separation distance in the second direction between the incident diffraction element and the output diffraction element, t is the width in the first direction of the substrate, and θ d is the diffraction angle in the first direction of the input diffraction element) 3. In Paragraph 2, A camera module in which the diffraction angle in the first direction of the input diffraction element is the angle formed with the first direction after the light passes through the input diffraction element.

4. In Paragraph 3, The output diffraction element includes a first region that overlaps with the light receiving part in the first direction and a second region that does not overlap, and A camera module in which the minimum width in the second direction of the output diffraction element is determined by the difference in width between the first region and the second region in the second direction.

5. In Paragraph 4, A camera module in which the minimum width in the second direction of the output diffraction element is determined by Equation 2. [Mathematical Formula 2] (Here, OC xmin is the minimum width in the second direction of the output diffraction element, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x is the angle of view in the second direction of the light receiver, and x is the width in the second direction of the light receiver) 6. In Paragraph 5, A camera module in which the maximum width in the second direction of the output diffraction element is determined by Equation 3. [Mathematical Formula 3] (Here, OC xmax is the maximum width in the second direction of the output diffraction element, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x is the angle of view in the second direction of the light receiver, x is the width in the second direction of the light receiver, and dx is the allowable width of the light receiver.

7. In Paragraph 2, A camera module in which the minimum separation distance in the second direction between the incident diffraction element and the center of the light receiving part is determined by Equation 4. [Mathematical Formula 4] (Here, minD is the minimum separation distance in the second direction between the center of the incident diffraction element and the light receiver, d is the separation distance in the first direction between the output diffraction element and the light receiver, and fov x is the angle of view in the second direction of the light-receiving part, x is the width in the second direction of the light-receiving part, t is the width in the first direction of the substrate, and θd is the diffraction angle in the first direction of the input diffraction element) 8. In Paragraph 1, A camera module in which the minimum width in the third direction perpendicular to the first direction and the second direction of the incident diffraction element is proportional to the separation distance in the second direction of the incident diffraction element.

9. In Paragraph 8, A camera module in which the minimum width in the third direction of the incident diffraction element is determined by Equation 5. [Mathematical Formula 5] (Here, minIC y is the minimum width in the third direction of the incident diffraction element, and d (IC- OC ) is the separation distance between the incident diffraction element and the output diffraction element in the second direction, and φ2 is the diffraction angle in the third direction of the input diffraction element.

10. In Paragraph 9, A camera module in which the diffraction angle in the third direction of the input diffraction element is the angle formed with the second direction on a plane perpendicular to the first direction after the light passes through the input diffraction element.

Images