JP2005031460A - Compound eye optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the ghost light produced by the stray light from proximate lenses of a compound eye optical system arranged with a plurality of the lenses in parallel. <P>SOLUTION: The microlenses constituting an imaging sensor for forming an image by a lens array guide efficiently obliquely incident rays to photosensors by decentering light shielding metallic layers in compliance with incident angles of incident rays, and degrade the sensitivities of the rays made incident with different angles. When the inclinations between the optical axes of the adjacent lenses of the compound eyes and their respective angles of view are set under prescribed conditions, the incident angles of the ghost light made incident on the respective photosensors are made into incident angles with lower senstivity to the photosensors, by which the ghost can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic imaging apparatus, and more particularly to a digital camera, and more particularly to a camera for a small portable terminal.

  Recent imaging systems have been mounted on notebook computers, portable information terminals, and mobile phones in addition to general cameras. In these applications, a smaller imaging system is desirable. In order to meet these requirements, electronic imaging devices such as CCD and CMOS are made smaller and the imaging system is downsized, or the number of lenses constituting the imaging system is reduced, and the imaging system is downsized and thinned. It is possible to do.

  However, miniaturization of the electronic image pickup device is difficult due to the problem of a decrease in light receiving sensitivity associated therewith, and there is a problem that it is difficult to correct aberrations to reduce the number of lenses.

On the other hand, a compound eye optical system that realizes a small and thin optical system by using an optical element in which a plurality of lenses are arranged in parallel is disclosed (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 10-145802

  However, the method disclosed in the publication requires a light-shielding member that is a field-of-view baffle to prevent stray light from adjacent lenses, so-called ghost light, and increases the thickness of the compound-eye optical system in the optical axis direction. There was a problem. In addition, it is necessary to dispose a spacer that also serves as a light shield between adjacent lenses. Therefore, there is a problem that the area of the lenslet and the light receiving element is increased.

In order to solve the above problems, the first invention according to the present invention is:
A compound-eye optical system comprising an optical element in which a plurality of lens blocks having condensing power are arranged, an aperture stop for restricting a light beam incident on the lens block, and an imaging element for capturing a subject image formed by the optical element And
The imaging element includes a plurality of imaging areas corresponding to a plurality of lens blocks of the optical element in a one-to-one relationship, and the plurality of imaging areas are each configured by a plurality of pixels, In a compound eye optical system composed of a light receiving element that detects light and a light shielding mask that prevents a light beam incident on the pixel from reaching an adjacent light receiving element,
The center of the opening of the light shielding mask is arranged substantially along the light beam incident on the corresponding light receiving element.

Further, the second invention according to the present invention is:
Each of the plurality of pixels includes a light receiving element that detects light, a light shielding mask that prevents a light beam incident on the pixel from reaching an adjacent light receiving element, and a microlens that collects light on the pixel. ,
The center of the microlens and the center of the opening of the light shielding mask are arranged substantially along the light beam incident on the corresponding light receiving element.

Further, the third invention according to the present invention is
The angle θ formed by the optical axis of the lens block, the optical axis of the lens block adjacent to the lens block, and the half angle of view ω of each lens block satisfy the relationship θ + ω> 20 °.

The fourth invention according to the present invention is
The optical axes of the plurality of lens blocks are substantially parallel.

The fifth invention according to the present invention is:
The optical axes of the plurality of lens blocks are arranged with an inclination to each other.

  As described above, if the present invention is organized and summarized, it can be integrated into the following configurations.

(1) An optical element in which a plurality of lens blocks having a condensing power are arranged, an aperture stop for restricting a light beam incident on the lens block, and an image pickup element that captures a subject image formed by the optical element. A compound eye optical system,
The imaging element includes a plurality of imaging areas corresponding to a plurality of lens blocks of the optical element in a one-to-one relationship, and the plurality of imaging areas are each configured by a plurality of pixels, In a compound eye optical system composed of a light receiving element that detects light and a light shielding mask that prevents a light beam incident on the pixel from reaching an adjacent light receiving element,
A compound eye optical system characterized in that an opening center of the light shielding mask is arranged substantially along a light ray incident on a corresponding light receiving element.

(2) Each of the plurality of pixels includes a light receiving element that detects light, a light shielding mask that prevents a light beam incident on the pixel from reaching an adjacent light receiving element, and a microlens that collects light on the pixel. Consisting of
The compound-eye optical system according to (1), wherein the center of the microlens and the center of the opening of the light-shielding mask are disposed substantially along a light beam incident on a corresponding light receiving element.

  (3) The angle θ formed by the optical axis of the lens block, the optical axis of the lens block adjacent to the lens block, and the half angle of view ω of each lens block satisfy the relationship θ + 2ω> 20 °. The compound eye optical system according to (1) or (2).

  (4) The compound eye optical system according to any one of (1) to (3), wherein optical axes of the plurality of lens blocks are substantially parallel.

  (5) The compound-eye optical system according to any one of (1) to (3), wherein optical axes of the plurality of lens blocks are arranged with an inclination.

As explained above, according to the first and second inventions of the present invention,
A compound-eye optical system comprising an optical element in which a plurality of lens blocks having condensing power are arranged, an aperture stop for restricting a light beam incident on the lens block, and an imaging element for capturing a subject image formed by the optical element And
The imaging element includes a plurality of imaging areas corresponding to a plurality of lens blocks of the optical element in a one-to-one relationship, and the plurality of imaging areas are each configured by a plurality of pixels, In a compound eye optical system composed of a light receiving element that detects light, a light shielding mask that prevents a light beam incident on the pixel from reaching an adjacent light receiving element, and a microlens that collects light on the pixel,
By arranging the opening center of the light shielding mask substantially along the light beam incident on the corresponding light receiving element, and by arranging the center of the micro lens substantially along the light beam incident on the corresponding light receiving element It becomes possible to efficiently guide the light incident on the photosensor to the photosensor.

According to the third invention of the present invention,
Ghost light is configured such that the optical axis of the lens block, the angle θ formed by the optical axis of the lens block adjacent to the lens block, and the half angle of view ω of each lens block satisfy the relationship θ + 2ω> 20 °. Can be prevented.

According to the fourth invention of the present invention,
By making the optical axes of the plurality of lens blocks substantially parallel, an optical system capable of capturing a stereo image can be realized.

According to the fifth aspect of the present invention,
By arranging the optical axes of the plurality of lens blocks so as to be inclined, it is possible to realize an optical system capable of photographing the entire subject image with the entire lens block.

  Next, examples of the present invention will be described.

  1 and 2 are a top view and a side sectional view of a compound eye optical system according to a first embodiment of the present invention. FIG. 3 is a developed view of the compound eye optical system of the present embodiment for the sake of explanation.

  The compound eye optical system 1 includes a diaphragm member 2, an optical element 3, an optical filter 4, and an image sensor 5.

  The image sensor 5 is an image sensor such as a CMOS sensor or a CCD sensor, and is composed of an image area 6 and a drive processing circuit 7 composed of a plurality of light receiving units.

  The aperture member 2 is provided with a plurality of openings, 2-1, 2-2, 2-3, 2-4 to 2-25. These openings are arranged such that the left end of the first stage in the figure is 2-1, then 2-2, 2-3, 2-4, 2-5 toward the right, and then the left end of the second stage is 2 -6, and the following are arranged 2-7, 2-8, 2-9, 2-10 toward the right. Thereafter, the same arrangement is made, and 2-25 is arranged at the right end of the fifth stage.

  The optical element 3 is formed by integrating a plurality of lens blocks 3-1, 3-2, 3-3, 3-4, 3-5 to 3-25. The plurality of lens blocks 3-1 to 3-25 are also arranged so that the left end of the first step is 3-1, and the right end of the fifth step is 3-25, like the opening. The optical element 3 is made of a transparent material such as plastic or glass.

  The optical filter 4 is configured by an optical low-pass filter, an infrared cut filter, or the like.

  The surface of the optical filter is configured to be opaque except for the transmission regions 4-1, 4-2, and 4-25.

  Next, the imaging action in the compound eye optical system of the present invention will be described.

  Of the light rays from the subject (not shown), the light rays that have passed through the aperture 2-1 are refracted by the lens block 3-1, then pass through the transmission region 4-1, and then pass through the optical filter 4. An image is formed on the imaging area 6.

  FIG. 4 is a diagram schematically illustrating the imaging in the imaging area 6, and the light beam that has passed through the opening 2-1 forms a subject image on the imaging area 6-1.

  Therefore, the path from the opening 2-1 to the imaging region 6-1 functions as one imaging optical system (hereinafter referred to as an imaging block). Similarly, the path from the opening 2-2 to the imaging area 6-2 and the path from the opening 2-3 to the imaging area 6-3 also function as an imaging block, and the subsequent opening 2-25 to the imaging area. The route to 6-25 also functions as an imaging block.

  In addition, since the transmissive area 4-1 is an opaque body having an opening only at a position corresponding to the lens block 3-1, for example, a light ray incident on the opening 2-1 reaches other than the imaging area 6-1. It is possible to prevent this from occurring to some extent, and similarly, it is possible to prevent to some extent that rays incident from other than the opening 2-1 reach the imaging region 6-1. Similarly, the transmissive areas 4-2 to 4-25 prevent rays from other than the corresponding lens blocks from reaching other imaging areas.

  In the present embodiment, the optical axes of the respective imaging blocks are arranged with an inclination.

  FIG. 2 is a side cross-sectional view passing through the aperture centers of the aperture stops 2-11 to 2-15 of the compound-eye optical system 1. In the figure, the lines indicated by the alternate long and short dash lines represent the optical axes of the respective lens blocks. ing. For example, the optical axis 8-11 is a line segment that passes through the aperture center of the aperture stop 2-11, passes through the optical center of the lens block 3-11, and reaches the imaging region 6-11.

  In the following description, the x direction in FIG. 1 will be described as a horizontal direction and the y direction as a vertical direction.

  The optical axis 8-13 of the central lens block 3-13 in the plurality of lens blocks constituting the compound eye optical system of the present embodiment is configured to be substantially perpendicular to the paper surface in FIG. The photographing field angle of the lens block 3-13 is configured to be 2ω = 10 ° in the horizontal direction (half field angle of 10 °) and 2ω = 10 ° in the vertical direction.

  The optical axis 8-14 of the lens block 3-14 is disposed with an inclination of approximately 10 ° in the horizontal direction with respect to the optical axis 8-13. Further, the photographing field angle of the lens block 3-14 is configured to be 2ω = 10 ° in the horizontal direction and 2ω = 10 ° in the vertical direction. Therefore, the lens block 3-14 images a region of 5 ° to 15 ° with a horizontal field angle of 10 ° as a center.

  Next, the optical axis 8-15 of the lens block 3-15 is disposed with an inclination of approximately 20 ° in the horizontal direction with respect to the optical axis 8-13. The shooting field angle of the lens block 3-15 is configured to be 2ω = 10 ° in the horizontal direction and 2ω = 10 ° in the vertical direction. Therefore, the lens block 3-15 images a region from 15 ° to 25 ° around a horizontal angle of view of 20 °.

  Further, the optical axis 8-12 of the lens block 3-12 is disposed with an inclination of about −10 ° in the horizontal direction with respect to the optical axis 8-13. In addition, the photographing field angle of the lens block 3-12 is configured to be 2ω = 10 ° in the horizontal direction and 2ω = 10 ° in the vertical direction. Therefore, the lens block 3-12 images a region from −5 ° to −15 ° with a horizontal angle of view of −10 °.

  Further, the optical axis 8-11 of the lens block 3-11 is disposed with an inclination of about −20 ° in the horizontal direction with respect to the optical axis 8-13. The photographing field angle of the lens block 3-11 is configured to be 2ω = 10 ° in the horizontal direction and 2ω = 10 ° in the vertical direction. Therefore, the lens block 3-11 images a region from −15 ° to −25 ° with a horizontal field angle of −20 ° as a center.

  Similarly, the optical axis of each lens block is arranged with an inclination with respect to the optical axis 8-13, and the shooting field angle of each lens block is 2ω = 10 ° in the horizontal direction and in the vertical direction. It is comprised so that it may become 2omega = 10 degrees. With this configuration, each lens block captures a different area, and the entire lens block can be imaged with a horizontal field angle of 50 ° and a vertical field angle of 50 °.

  In other words, with the configuration as in the present embodiment, each lens block forms a different portion of the subject, i.e., a partially divided image of the subject, on the corresponding imaging region, and the entire lens block of the subject. A whole image is formed on the imaging area 6.

  The drive processing circuit 7 drives the imaging area 6 and reads out a partial divided image of the subject formed by each lens block in the corresponding imaging area. Next, the drive processing circuit 7 performs a process of joining the partial divided images of the subject and outputs an image as a whole subject image.

  Next, the structure of the image sensor 5 will be specifically described.

  As described above, the imaging sensor 5 includes the imaging area 6 including a plurality of light receiving units. FIG. 5 is an enlarged cross-sectional view of a part of the imaging area 6.

  In the figure, reference numeral 9 denotes a substrate formed of silicon or the like, and a photosensor 10 that receives light and converts it into an electrical signal is formed on the substrate 9. Above the photosensor 10, wiring layers 11-1 and 11-2 for supplying power to the photosensor 10 and reading signals from the photosensor 10 are formed. The wiring layers 11-1 and 11-2 are made of an opaque metal and are formed in a direction perpendicular to the paper surface of FIG.

A light shielding metal layer 16 is formed on the wiring layer 11. The wiring layer 11 and the light shielding metal layer 16 are formed in a transparent base material 15 such as SiO ₂ .

  A smooth layer 12 made of a transparent oxynitride film or the like is formed on the base material 15, and a color filter 13 such as a resin is formed on the smooth layer 12.

  On the color filter 13, a microlens 14 for effectively guiding a light beam to the photosensor 10 is formed. Note that the microlens 14 is made of a transparent material such as a resin.

  In the figure, a region from a dotted line to a dotted line represents a unit of one light receiving unit, and the imaging area 6 is composed of a plurality of such light receiving units.

  The color filter 13 has a characteristic of selectively transmitting only light of a specific color such as red, green, and blue. Further, the color filter 13 of the light receiving unit in the center in the drawing is green, the color filter 13 of the light receiving unit in the left in the drawing is red, the color filter 13 of the right light receiving unit in the drawing is blue, and so on. The color information of the subject can be acquired by periodically changing the color transmitted through the color filter 13 in the unit. In addition to the combination of red, green, and blue, the same effect can be expected if the color filter 13 has a characteristic of transmitting colors such as yellow, magenta, cyan, and green.

  In the figure, a one-dot chain line represents a light beam incident on the light receiving unit.

  The light shielding metal layer 16 is made of an opaque metal or the like and has a structure having an opening only under the microlens 14. With such a configuration, the light beam incident on the microlens 14 is prevented from entering the adjacent photosensor 10.

  Next, a method for preventing stray light in this embodiment will be described.

  FIG. 6 is a side cross-sectional view of the compound eye optical system 1 in the present embodiment, and only the lens block 3-13 and the lens block 3-14 adjacent thereto are illustrated for explanation.

  A one-dot chain line in the drawing represents a principal ray at a central field angle of each lens block, that is, an optical axis of each lens block. The broken lines represent the principal rays with the maximum and minimum angles of view in the horizontal direction of the respective lens blocks. Although these light rays are originally bent curves due to the refraction action of a lens block or the like, they are displayed as straight lines in the figure for explanation. In this embodiment, the shooting field angle 2ω of each lens block is 10 °. The angle θ formed by the optical axes of adjacent lens blocks is 10 °.

  The structure of the light receiving unit at point A on the image sensor 5 is shown in FIG. The structure of the light receiving unit at point B is shown in FIG. Similarly, the structure of the light receiving unit at point C is shown in FIG.

  At point A in FIG. 6, the light beam from the lens block 3-13 enters the image sensor 5 substantially perpendicularly. Therefore, as shown in FIG. 7A, in the light receiving unit at the point A, the center of the microlens 14 and the center of the opening of the light shielding metal layer 16 are arranged along the optical axis indicated by the one-dot chain line. . FIG. 8A shows a graph of measurement results of the coupling efficiency of incident light to the photosensor 10 in the case of such a light receiving unit structure. In the figure, the horizontal axis represents the angle of light incident on the microlens 14 of the light receiving unit, and the vertical axis represents the intensity of light reaching the photosensor 10. The light intensity on the vertical axis is normalized with the light intensity when the angle of incidence on the microlens 14 is 0 ° being 1. As shown in the figure, in the light receiving unit at the point A, when the incident angle of the light beam from the lens block 3-13 to the imaging sensor 5 is 0 °, the intensity of the light beam reaching the photosensor 10 is maximum, and the incident angle is 20 °. It becomes almost zero in degree. The reason why the light beam reaching the photosensor 10 with a light beam having a large incident angle is weakened is that the light beam that has passed through the microlens is shielded by the light shielding metal layer 16 and the wiring layers 11-1 to 11-2. is there.

  Next, at the point B in FIG. 6, the light beam from the lens block 3-13 enters the image sensor 5 at an angle −ω. In this embodiment, ω = 5 °. Therefore, as shown in FIG. 7B, in the light receiving unit at the point B, the center of the microlens 14 and the opening center of the light shielding metal layer 16 are arranged along the principal ray indicated by the one-dot chain line. . FIG. 8B shows a graph of the measurement result of the coupling efficiency of incident light to the photosensor 10 in the case of such a light receiving unit structure. The light intensity on the vertical axis is normalized with the light intensity when the angle of incidence on the microlens 14 is −5 °. As shown in the figure, in the light receiving unit at the point B, when the incident angle of the light beam from the lens block 3-13 to the imaging sensor 5 is −5 °, the light beam reaching the photosensor 10 has the maximum intensity, and the incident angle is 15 It becomes almost 0 when the angle exceeds or is less than −25 °.

  Next, at a point C in FIG. 6, the light beam from the lens block 3-14 enters the imaging sensor 5 at an angle θ + ω. In this embodiment, ω = 5 ° and θ = 10 °. Therefore, as shown in FIG. 7C, in the light receiving unit at the point C, the center of the microlens 14 and the opening center of the light shielding metal layer 16 are arranged along the principal ray indicated by the one-dot chain line. . FIG. 8C shows a graph of the measurement result of the coupling efficiency of incident light to the photosensor 10 in the case of such a light receiving unit structure. The light intensity on the vertical axis is normalized with the light intensity when the angle of incidence on the microlens 14 being 15 ° is 1. As shown in the figure, in the light receiving unit at the point C, when the incident angle of the light beam from the lens block 3-14 to the imaging sensor 5 is 15, the light beam intensity reaching the photosensor 10 is maximum, and the incident angle is 30 °. When the angle exceeds or is less than −5 °, it becomes almost zero.

  Similarly, in the light receiving unit at an arbitrary point on the image sensor 5, the center of the microlens 14 and the center of the opening of the light shielding metal layer 16 are arranged along the incident principal ray, and thus the main light incident on the light receiving unit. The light beam intensity reaching the photosensor 10 is maximized at the light beam angle.

  As shown in FIG. 4, the imaging areas corresponding to the adjacent lens blocks are also adjacent on the imaging area 6.

  Specifically, for example, in FIG. 6, imaging regions 6-13 and 6-14 corresponding to adjacent lens blocks 3-13 and 3-14 are also adjacent. Therefore, the point B that is the image point of the maximum angle of view of the lens block 3-13 and the point C that is the image point of the maximum angle of view of the lens block 3-14 are adjacent. Therefore, there is a possibility that a light ray (a two-dot chain line in the figure) incident on the lens block 3-13 exceeding the maximum angle of view reaches the point C and generates a ghost. Conventionally, in order to prevent such ghost light, it has been necessary to take measures against ghost such as providing a partition between adjacent lens blocks 3-13 and 3-14.

  In the present embodiment, as described above, the angle θ formed by the optical axes of adjacent lens blocks is set to 10 °, and the field angle 2ω of each lens block is set to 10 °. Therefore, the angle formed between the light rays reaching the adjacent imaging region as indicated by α in FIG. 6 is θ + 2ω, and is 20 ° in this embodiment. As described above, for example, the light receiving unit at the point B in FIG. 6 is configured to have the maximum light intensity reaching the photosensor 10 at the incident angle of −5 °, and 20 for the incident angle of −5 °. With respect to light incident at an angle of more than 0 °, the reaching light intensity is substantially zero. Therefore, even when ghost light from the adjacent lens block 3-14 enters the point B, the light beam does not reach the photosensor 10 at the point B and does not cause ghost.

  In addition, although it demonstrated in the case of the lens block 3-13 and the lens block 3-14, it is the same also in another lens block, and generation | occurrence | production of the ghost by the light ray from an adjacent lens block can be prevented in a present Example.

  In this embodiment, the angle θ formed by the optical axes of adjacent lens blocks is set to 10 °, and the angle of view 2ω of each lens block is set to 10 °. However, as long as θ + 2ω exceeds 20 °. Similar effects can be expected. Further, if the condition of θ + 2ω exceeds 40 °, it is more effective because the intensity of the ghost light reaching the photosensor 10 can be further reduced.

  As described above, in this embodiment, since it is possible to prevent ghost light from adjacent lens blocks, a shielding object such as a screen that has been conventionally required between the lens blocks is unnecessary. It is possible to reduce the number of parts and reduce the cost, and it is possible to make the entire optical system compact.

  Next, a second embodiment of the present invention will be described.

  10 and 11 are a top view and a side sectional view of the compound eye optical system according to the second embodiment of the present invention. Further, FIG. 9 shows a developed view of the compound eye optical system of the present embodiment for explanation.

  The description of the same components as those in the first embodiment will be omitted.

  In the present embodiment, the optical axes of the lens blocks 3-1, 3-2, 3-3, 3-4 are all substantially parallel. In addition, the focal lengths of the lens blocks 3-1, 3-2, 3-3, and 3-4 are configured to be equal, and the shooting angle of view 2ω of each lens block is also configured to be equal. Therefore, in the present embodiment, the subject on which each lens block forms an image is substantially the same, and the captured images are so-called stereo images having minute parallax. In this embodiment, the photographing field angle 2ω of each lens block is 40 °.

  An imaging area 6 composed of a plurality of light receiving units is formed on the imaging sensor 5. As in the first embodiment, each light receiving unit is arranged such that the center of the microlens constituting the light receiving unit and the opening center of the light shielding metal layer are along the principal ray of the incident field angle. In FIG. 2, the light beam reaching the photosensor has a maximum intensity.

  In FIG. 11, the angle α formed by the maximum field angle rays of the adjacent lens blocks 3-1 and 3-2 is 40 ° in this embodiment. Therefore, similarly to the first embodiment, it is possible to prevent a light beam incident on an adjacent lens block from exceeding the maximum angle of view from generating ghost light in the imaging area 6.

The top view of the 1st Example of the compound-eye optical system of this invention Side sectional view of the first embodiment of the compound eye optical system of the present invention Exploded view of the first embodiment of the compound eye optical system of the present invention The figure explaining the imaging region in the compound eye optical system of this invention Side surface sectional drawing explaining the structure of the image sensor in the compound eye optical system of this invention Diagram explaining ghost light The figure explaining the structure of a light receiving element The figure explaining the structure of a light receiving element The figure explaining the structure of a light receiving element Graph of the intensity of light reaching the photosensor Graph of the intensity of light reaching the photosensor Graph of the intensity of light reaching the photosensor Development view of the second embodiment of the compound eye optical system of the present invention Top view of the second embodiment of the compound eye optical system of the present invention Side surface sectional drawing of 2nd Example of the compound-eye optical system of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compound eye optical system 2 Aperture member 3 Optical element 4 Shading filter (optical filter)
5 Imaging sensor 6 Imaging area 7 Drive processing circuit

Claims (5)

A compound-eye optical system comprising an optical element in which a plurality of lens blocks having condensing power are arranged, an aperture stop for restricting a light beam incident on the lens block, and an imaging element for capturing a subject image formed by the optical element And
The imaging element includes a plurality of imaging areas corresponding to a plurality of lens blocks of the optical element in a one-to-one relationship, and the plurality of imaging areas are each configured by a plurality of pixels, In a compound eye optical system composed of a light receiving element that detects light and a light shielding mask that prevents a light beam incident on the pixel from reaching an adjacent light receiving element,
A compound eye optical system characterized in that an opening center of the light shielding mask is arranged substantially along a light ray incident on a corresponding light receiving element. Each of the plurality of pixels includes a light receiving element that detects light, a light shielding mask that prevents a light beam incident on the pixel from reaching an adjacent light receiving element, and a microlens that collects light on the pixel. ,
2. The compound eye optical system according to claim 1, wherein the center of the microlens and the center of the opening of the light shielding mask are arranged substantially along a light ray incident on a corresponding light receiving element. The angle θ formed by the optical axis of the lens block, the optical axis of a lens block adjacent to the lens block, and the half angle of view ω of each lens block satisfy a relationship of θ + 2ω> 20 °. Item 3. The compound eye optical system according to Item 1 or 2. 4. The compound eye optical system according to claim 1, wherein optical axes of the plurality of lens blocks are substantially parallel. 4. The compound-eye optical system according to claim 1, wherein optical axes of the plurality of lens blocks are arranged with an inclination.

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