WO2007125761A1

WO2007125761A1 - Compound eye camera module

Info

Publication number: WO2007125761A1
Application number: PCT/JP2007/058139
Authority: WO
Inventors: Satoshi Tamaki; Tatsutoshi Suenaga; Katsumi Imada
Original assignee: Panasonic Corporation
Priority date: 2006-04-24
Filing date: 2007-04-13
Publication date: 2007-11-08
Also published as: JP2009164654A

Abstract

A compound eye camera module where a light shielding block (6) having openings (6a-6d) is provided between a lens array (1) and an imaging element (4). The lens array (1) is provided with lenses (1a-1d) having optical axes different from each other, and the imaging element (4) has imaging regions (4a-4d). The light shielding block has a first standard surface (68) in contact with the lens array and positioning it in the optical axis direction, a second standard surface (65) in contact with the imaging element and positioning it in the optical axis direction, a third standard surface (67) in contact with the lens array and positioning it ina first direction perpendicular to the optical axis direction, and a fourth standard surface (66) in contact with the lens array and positioning the lens array in a second direction perpendicular to the optical axis direction and the first direction. Although simply assembled, the compound eye camera module has high accuracy of measured distances and is small-sized and thin.

Description

Specification

Compound eye camera module

Technical field

The present invention relates to a small and thin camera module. In particular, the present invention relates to a compound-eye camera module that captures an image with a plurality of photographing optical lenses.

Background art

In an imaging apparatus such as a digital video or a digital camera, a subject image is converted into two-dimensional image information by forming a subject image on an image sensor such as a CCD or CMOS through a lens. Furthermore, a camera that measures distance information to a subject has also been proposed.

[0003] An example of measuring a distance to a subject with a compound eye camera module is described in Patent Document 1, which will be described with reference to FIG. A diaphragm member 111, a lens array 112, a light shielding block 113, an optical filter array 114, and an image sensor 116 are arranged in this order from the subject side. The lens array 112 includes a plurality of lenses. The diaphragm member 111 includes a diaphragm (aperture) at a position that coincides with the optical axis of each lens of the lens array 112. The optical filter array 114 includes a plurality of optical filters having different spectral characteristics for each region corresponding to each lens of the lens array 112, and covers the light receiving surface of the image sensor 116. The light blocking block 113 includes a light blocking wall 113a at a position that coincides with the boundary between adjacent lenses of the lens array 112, that is, the boundary between adjacent optical filters of the optical filter array 114. The image sensor 116 is mounted on the semiconductor substrate 115. On the semiconductor substrate 115, a driving circuit 117 and a signal processing circuit 118 are further mounted. With the camera module configured as described above, a plurality of images having parallax are obtained, and the amount of parallax is calculated from the plurality of images, and the distance to the subject is calculated based on the amount of parallax.

[0004] In order to further improve the distance accuracy, a camera module has been proposed that improves the distance accuracy by changing the combination of lenses and changing the inter-lens distance (base line length).

Patent Document 1: Japanese Unexamined Patent Publication No. 2003-143459

Disclosure of the invention

Problems to be solved by the invention However, the camera module shown in FIG. 19 has the following problems due to assembly variations. First, an error occurs in the amount of parallax calculated by the calculation, and as a result, the accuracy of the measurement distance deteriorates. Second, the light that has passed through each lens of the lens array 112 enters the light shielding wall 113a of the light shielding block 113, and the light is absorbed by the light shielding wall 113a, so that the entire subject image is captured on the light receiving surface of the imaging element 116. Alternatively, a force that does not form an image is generated, or unnecessary light is generated due to reflection of light by the light shielding wall 113a, thereby causing ghost. Both of these cause the measurement distance accuracy to deteriorate.

[0006] In order to improve the measurement distance accuracy, the base line length may be increased, but this is not preferable because it leads to an increase in the size of the camera module.

An object of the present invention is to provide a camera module that is small in size, has a short base line length, and can improve measurement distance accuracy.

Means for solving the problem

[0008] The compound-eye camera module of the present invention includes a lens array having a plurality of lenses arranged on a single plane and having different optical axes, and a plurality of one-to-one correspondences to each of the plurality of lenses. An image pickup device having an image pickup area; and a light-shielding block disposed between the lens array and the image pickup device and having a plurality of openings corresponding to each of the plurality of lenses. The light shielding block is in contact with the lens array, a first reference plane that positions the lens array in the optical axis direction, and a second reference surface that is in contact with the imaging element and positions the imaging element in the optical axis direction. A reference surface, a third reference surface that contacts the lens array and positions the lens array in a first direction orthogonal to the optical axis, and a contact with the lens array that aligns the lens array with the optical axis and the first array. And a fourth reference plane positioned in a second direction orthogonal to one direction.

The invention's effect

[0009] According to the present invention, since the assembly variation can be reduced, it is possible to prevent the measurement distance accuracy from being deteriorated due to the assembly variation. Accordingly, it is possible to provide a camera module with improved measurement distance accuracy even with a small camera module having a short base line length.

[0010] Furthermore, simple assembly without using a complicated and expensive adjustment mechanism during assembly. Even if the measurement is performed, the measurement distance accuracy can be improved, so that an inexpensive camera module can be provided.

Brief Description of Drawings

FIG. 1 is an exploded perspective view of a compound-eye camera module according to Embodiment 1 of the present invention.

[Fig. 2] Fig. 2 is a perspective view of the upper lens barrel as viewed from the side of the imaging device in the compound eye type camera module according to Embodiment 1 of the present invention.

FIG. 3A is a perspective view of the compound-eye camera module according to Embodiment 1 of the present invention as viewed from the subject side of the lens array.

FIG. 3B is a perspective view of the compound-eye camera module according to Embodiment 1 of the present invention as viewed from the image sensor side of the lens array.

[FIG. 4A] FIG. 4A is a perspective view showing the subject side force of the light-shielding block in the compound-eye camera module according to Embodiment 1 of the present invention.

FIG. 4B is a perspective view of the image sensor side force of the light shielding block in the compound eye type camera module according to Embodiment 1 of the present invention.

[FIG. 4C] FIG. 4C is a perspective view showing the subject side force of the light-blocking block in the compound-eye camera module according to Embodiment 1 of the present invention.

FIG. 5 is an exploded perspective view of another compound-eye camera module according to Embodiment 1 of the present invention, in which the light shielding wall and the outer cylinder portion are configured separately.

FIG. 6A is a ray diagram when no light-shielding film is provided in the compound-eye camera module according to Embodiment 1 of the present invention.

FIG. 6B is a ray diagram when a light-shielding film is provided in the compound-eye camera module according to Embodiment 1 of the present invention.

FIG. 7 is a plan view of a light shielding film in the compound-eye camera module according to Embodiment 1 of the present invention.

FIG. 8A is a plan view of a compound-eye camera module according to Embodiment 1 of the present invention.

FIG. 8B is a cross-sectional view taken along line 8B-8B in FIG. 8A. FIG. 9 is an exploded perspective view of a compound-eye camera module according to Embodiment 2 of the present invention.

FIG. 10 is a cross-sectional view of a compound eye type camera module according to Embodiment 2 of the present invention.

FIG. 11 is an exploded perspective view of a compound eye camera module according to Embodiment 3 of the present invention.

FIG. 12 is a cross-sectional view of a compound eye type camera module according to Embodiment 3 of the present invention.

FIG. 13 is an exploded perspective view of a compound-eye camera module according to Embodiment 4 of the present invention.

FIG. 14 is an exploded perspective view of another compound-eye camera module according to Embodiment 4 of the present invention.

FIG. 15 is an exploded perspective view of still another compound-eye camera module according to Embodiment 4 of the present invention.

FIG. 16 is an exploded perspective view of still another compound-eye camera module according to Embodiment 4 of the present invention.

FIG. 17 is an exploded perspective view of still another compound eye camera module according to Embodiment 4 of the present invention.

FIG. 18 is a perspective view of another outer cylinder portion viewed from the image sensor side in a compound eye type camera module according to the present invention.

FIG. 19 is an exploded perspective view of an imaging system of a conventional camera module.

BEST MODE FOR CARRYING OUT THE INVENTION

The compound eye type camera module of the present invention described above is an optical filter module that is disposed between the lens array and the image sensor and transmits light in a specific wavelength band among light transmitted through the plurality of lenses. Furthermore, it is preferable to have. In this case, it is preferable that the light shielding block has a fifth reference surface that abuts the optical filter module and positions the optical filter module in the optical axis direction. As a result, the tilt of the optical filter module can be suppressed. Thus, it is possible to further prevent bad measurement distance accuracy due to variations.

[0013] The compound-eye camera module of the present invention described above is disposed between the lens array and the optical filter module, and has a plurality of openings corresponding to each of the plurality of lenses. It is preferable to further have a light shielding film. In this case, it is preferable that the plurality of openings of the light shielding film have the same size as or smaller than the plurality of openings of the light shielding block. Thereby, it is possible to prevent unnecessary light that has passed through a lens not corresponding to the imaging region from entering each imaging region. Therefore, it is possible to further prevent the measurement distance accuracy from being deteriorated.

[0014] (Embodiment 1)

Embodiment 1 of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a compound-eye camera module according to Embodiment 1 of the present invention. In FIG. 1, 1 is a lens array, 2 is an optical filter module, 3 is a substrate, 4 is an image sensor, 5 is an upper barrel, 6 is a light-blocking block, 7 is a lens module, and 8 is a light-shielding film. For convenience of explanation, the XYZ Cartesian coordinate system as shown is set. Here, the Z-axis passes through almost the center of the effective pixel area of the image sensor 4 and is perpendicular to this. The X axis is perpendicular to the Z axis and is parallel to the light shielding walls 6 la and 61c described later of the light shielding block 6, and the Y axis is orthogonal to the Z axis and is described later as light shielding walls 6 lb and 6 Id of the light shielding block 6. It is a parallel axis. The arrow side of the X, Y, and Z axes is the positive side of each axis. In the Z-axis direction, the positive side of the Z-axis (upper side of the paper in FIG. 1, the subject side) is the “upper side” of the camera module, and the negative side of the Z-axis (lower side of the paper in FIG. 1, image side) is the camera module. Called the "lower side".

The lens array 1 integrally has four single lenses la to ld arranged on the same plane parallel to the XY plane. Four lenses la ~: Each optical axis of Ld is parallel to the Z axis, and is arranged at four vertices of a virtual rectangle parallel to the XY plane. Lens la ~: Two of Ld should satisfy the optical specifications such as MTF required for light in the wavelength band of red, blue, or green among the three primary colors of light. The remaining two are designed to satisfy the optical specifications such as MTF required for light in the near-infrared wavelength band! In one embodiment, the lenses la and lb are optimally designed for light in the wavelength bands of green and the lenses lc and Id in the near infrared. Lens la ~: Ld is made of a material such as glass or plastic. Formed in the body. The flange back deviation between the lenses optimally designed for light in the same wavelength band (in one embodiment, between the lenses la and lb corresponding to green light and between the lenses lc and Id corresponding to near-infrared light) is It is considered to be zero as much as possible.

Each of the lenses la to ld causes light from a subject (not shown) to form an image on the image sensor 4 after passing through the optical filter module 2.

The optical filter module 2 is disposed between the lens array 1 and the image sensor 4. Similarly to the lens array 1, the optical filter module 2 includes two optical filters 2a and 2c arranged on the same plane parallel to the XY plane. The two optical filters 2a and 2c transmit only light in any wavelength band of red, green, blue, and near infrared, respectively. In one embodiment, the optical filter 2a transmits light only in the wavelength band of green and the optical filter 2c transmits in the near-infrared wavelength band. When it is necessary to cut off infrared rays, the characteristics may be added to the optical filter 2a that transmits light in the visible wavelength band. The optical filter that transmits light in the same wavelength band is integrally formed. The optical filter 2a is disposed on the optical axes of the lenses la and lb, and the optical filter 2c is disposed on the optical axes of the lenses lc and Id.

The image sensor 4 is an image sensor such as a CCD or a CMOS, and includes a large number of pixels arranged two-dimensionally in the vertical and horizontal directions. The effective pixel area of the image sensor 4 is substantially equally divided into four image areas 4a to 4d. The four imaging regions 4a to 4d are arranged on the optical axes of the four lenses la to Id, respectively. As a result, on the four imaging regions 4a to 4d, subject images that have power only in the wavelength components of red, green, blue, and near infrared are independently formed. In one embodiment, the light from the subject that has passed through the lens la enters the optical filter 2a, and only the light in the green wavelength band passes through it and forms a subject image consisting of only the green wavelength component on the imaging region 4a. Image. Similarly, the light from the subject that has passed through the lens lb enters the optical filter 2a, and only the light in the green wavelength band passes through it to form a subject image in which only the green wavelength component has power on the imaging region 4b. To do. Light from the subject that has passed through the lens lc is incident on the optical filter 2c, and only near-infrared wavelength band light passes through it, forming an image of the subject that has power only in the near-infrared wavelength component on the imaging region 4c. To do. The light from the subject that has passed through the lens Id enters the optical filter 2c, and only the light in the near-infrared wavelength band passes through it. A subject image consisting only of near-infrared wavelength components is formed on the imaging region 4d.

[0020] Each pixel constituting the imaging regions 4a to 4d of the imaging device 4 photoelectrically converts light from an incident subject and outputs an electrical signal (not shown) corresponding to the intensity of the light.

[0021] The electric signal output from the image sensor 4 is subjected to various signal processing and image processing. For example, by using two images captured by the imaging regions 4a and 4b where green wavelength band light is imaged, the amount of parallax between these images can be obtained and the distance to the subject can be measured. Similarly, using two images captured by the imaging regions 4c and 4d where near-infrared wavelength band light is imaged, the amount of parallax between these images may be obtained and the distance to the subject measured. . Since two visible light images and two near-infrared light images are available, the distance to the subject can be measured day and night. These processes can be performed using a digital signal processor (DSP, not shown).

As shown in FIG. 2, the upper barrel 5 is provided with a recess 51 on the lower surface thereof for holding and fixing the lens array 1. The upper lens barrel 5 includes reference surfaces 52 and 53 facing the concave portion 51 side. The reference planes 52 and 53 are parallel to the Z axis. The reference plane 52 is parallel to the Y axis, and the reference plane 53 is parallel to the X axis. The upper lens barrel 5 has four apertures (openings) 5a to 5d at positions where the optical axes of the four lenses la to Ld of the held lens array 1 pass. The upper lens barrel 5 is made of a material that does not transmit light, and blocks external light that does not require any force other than the diaphragms 5a to 5d from entering the lenses la to Ld.

3A and 3B are perspective views of the lens array. 3A is a perspective view seen from the subject side, and FIG. 3B is a perspective view seen from the image sensor side. The lens array 1 includes reference surfaces 12 and 13 around the lens array 1. The reference plane 12 is parallel to the Z axis and points in the positive direction of the X axis. The reference plane 13 is parallel to the Z axis and points in the positive direction of the Y axis. The lens array 1 includes four reference surfaces 14 facing the image sensor side.

[0024] The reference surface 52 provided on the upper lens barrel 5 and the reference surface 12 provided on the lens array 1 are pressed in the X-axis direction, and the reference surface 53 provided on the upper lens barrel 5 is The reference surface 13 provided on the lens array 1 is pressed against the Y-axis direction, and the lens array 1 is fitted and fixed in the recess 51 of the upper barrel 5. As a result, the centers of the four stops 5a to 5d provided in the upper barrel 5 and the optical axes of the lenses 1a to Id coincide with each other. Force the lens array 1 and hold it The lens module 7 is composed of the lens barrel 5. The depth of the recess 51 in the Z-axis direction is shallower than the thickness of the lens array 1 in the Z-axis direction. Accordingly, in a state where the lens array 1 is held by the upper lens barrel 5, a part of the reference surfaces 12 and 13 provided around the lens array 1 is exposed.

As shown in FIG. 4A, the light shielding block 6 includes light shielding walls 6 la to 6 Id arranged in a cross shape so as to form four openings 6a to 6d independent of each other, and the light shielding walls 6 la to 6 Provided with an outer cylindrical portion 62 for holding Id. The light shielding walls 61a to 61d extend radially with respect to the Z axis, which is the central axis of the light shielding block 6, the light shielding walls 61a and 61c are along the XZ plane, and the light shielding walls 61b and 61d are along the YZ plane. . The four openings 6a to 6d are arranged on the optical axes of the four lenses la to ld, respectively. The light shielding walls 61a to 61d divide the effective pixel area of the image sensor 4 into four image areas 4a to 4d. The sizes of the openings 6a to 6d viewed along the Z axis are substantially the same as or larger than the imaging regions 4a to 4d. Lenses la ~: The light from the subject that has passed through Ld passes through the openings 6a-6d and is imaged on the imaging regions 4a-4d, respectively. The light shielding walls 61a to 61d prevent the light force that has passed through one of the lenses la to ld from entering an imaging area that does not correspond to this lens. For example, the green wavelength band light incident obliquely on the lens la and passed through the optical filter 2a is not incident on the imaging region 4c where only the near-infrared wavelength band light should be incident. A light shielding wall 6 Id that blocks light in the green wavelength band is provided along the boundary between the imaging region 4a and the imaging region 4c. The outer cylindrical portion 62 surrounding the openings 6a to 6d prevents external light that does not pass through the lens array 1 and the optical filter module 2 from entering the imaging regions 4a to 4d. In this manner, the light blocking block 6 can prevent the generation of stray light or the like that prevents unnecessary light from entering each of the imaging regions 4a to 4d. In order to effectively exhibit this function, the light shielding block 6 also has a material force that does not transmit light, like the upper lens barrel 5. Further, the inner surfaces of the light shielding walls 61a to 61d and the outer cylindrical portion 62 exposed in the openings 6a to 6d are subjected to various surface treatments (for example, roughening treatment, plating, black, etc.) so that light reflection is minimized. It is preferable that the surface is subjected to a shading process, or a light shielding surface having a taper (that is, a surface inclined with respect to the Z axis) is formed.

[0026] It should be noted that the light shielding walls 61a to 61d and the outer cylindrical portion 62 are configured separately to give a desired shape to the surfaces of the light shielding walls 61a to 61d and reduce the reflection of light on the light shielding wall surfaces. May be. Figure 5 shows an exploded perspective view of an example. Integrally formed light shielding wall 6 la ~ 6 Id and outer cylinder part 62 By assembling, the shading block 6 is obtained. By configuring the light shielding walls 61a to 61d separately from the outer cylindrical portion 62, it is possible to eliminate the restrictions caused by the mold structure and the like regarding the shape to be imparted to the light shielding wall surface, and the light from the light shielding walls 61a to 61d can be removed. It is possible to further reduce reflection.

Further, as shown in FIG. 4C, a light shielding wall 64 is formed on the subject side end face of the light shielding walls 61b and 61d so as to shield light between the optical filters 2a and 2c.

[0028] Further, the lens array 1 side surface of the light blocking block 6 is provided with a recess 63 for holding and fixing the optical filter module 2. The optical filter module 2 is positioned and fixed with respect to the light shielding block 6 by being inserted into the recess 63. The optical filter 2a and the optical filter 2c are arranged so as to close the openings 6a and 6b and the openings 6c and 6d, respectively. Furthermore, the optical filters 2a and 2c are brought into contact with a reference surface (fifth reference surface) 612 that is orthogonal to the Z axis provided on the light shielding block 6 that is the bottom surface of the recess 63, and positioned in the Z axis direction. The tilt of each optical filter 2a, 2c is suppressed.

FIG. 4B shows a perspective view of the light blocking block 6 as viewed from the image sensor 4 side. The Z axis, which is the central axis of the light shielding block 6, passes through a predetermined position of the effective pixel area of the image sensor 4, and the light shielding walls 61 a to 61 d of the light shielding block 6 include a large number of pixels constituting the image sensor 4. The light shielding block 6 is positioned with respect to the image sensor 4 and fixed on the substrate 3 so as to coincide with the vertical and horizontal arrangement directions. As a result, the effective pixel area of the image sensor 4 is divided into four image areas 4a to 4d corresponding to the four openings 6a to 6d. At this time, in order to make the focal positions of the lenses la to Ld coincide with the light receiving surfaces of the imaging regions 4a to 4d, respectively, and to suppress the tilt of the lens array 1 and the optical filter module 2, the three light shielding blocks 6 are provided. A reference plane (second reference plane) 65 abuts on the upper surface of the image sensor 4.

[0030] As shown in FIG. 4A, the light-blocking block 6 includes a reference plane (third reference plane) 67 that is parallel to the Z axis and faces the negative direction of the X axis, and a Y axis that is parallel to the Z axis. The negative reference plane (fourth reference plane) 66 and the four positive reference planes (first reference plane) 68 in the positive Z-axis direction.

The lens module 7 in which the lens array 1 is fixed to the upper barrel 5 presses the reference surface 12 provided on the lens array 1 against the reference surface 67 provided on the light shielding block 6, and the light shielding probe. Press the reference surface 13 provided on the lens array 1 against the reference surface 66 provided on the It is inserted into the shading block 6 and fixed. As a result, the optical axis of each lens and the corresponding imaging area are positioned in a direction orthogonal to the Z axis. As a result, the light that has passed through each of the lenses la to Ld is incident on the inner walls of the light shielding walls 61a to 61d and the outer cylinder 62, and the force that does not form a part of the subject image in the imaging areas 4a to 4d. It is possible to prevent the reflected light from entering the imaging areas 4a to 4d as unnecessary light.

[0032] It should be noted that assembly windows (through holes) 69x, 69y are provided in the outer cylindrical portion 62 of the light shielding block 6, and the lens array 1 is placed on the positive side of the X axis and the Y axis through the windows 69x, 69y. The positioning accuracy in the direction perpendicular to the Z axis may be improved by pressing directly toward the positive side.

[0033] Further, by pressing the reference surface 14 provided in the lens array 1 against the reference surface 68 provided in the light shielding block 6, and positioning the lens module 7 in the Z-axis direction with respect to the light shielding block 6, Corresponding lens la to the light receiving surfaces of the imaging regions 4a to 4d: The deviation of the focal position of Ld in the Z-axis direction can be made zero as much as possible.

[0034] Light with strong subject power should be incident on the imaging region corresponding to the lens that has passed through. If the incident angle of the light passing through the lens with respect to the optical filter module 2 is large, there is a possibility that the light enters the imaging region not corresponding to the lens through which the light passes. For example, light that has passed through the lens la should originally pass through the optical filter 2a, exit into the opening 6a of the light blocking block 6, and form an image only in the imaging region 4a. However, when the incident angle of the light that has passed through the lens la with respect to the optical filter module 2 is large, the light that has passed through the lens la passes through, for example, the optical filter 2a and exits into the opening 6b of the light shielding block 6, The light may enter the imaging region 4b, pass through the optical filter 2c, exit into the opening 6c of the light shielding block 6, and enter the imaging region 4c. As described above, when unnecessary light that has passed through the lens that does not correspond to the imaging region is incident on each imaging region, the measurement distance accuracy deteriorates. In order to prevent this, a light shielding film 8 is preferably provided. In the present embodiment, the light shielding film 8 is provided between the lens array 1 and the optical filter module 2 on the upper surfaces of the optical filters 2a and 2c. The operation of the light shielding film 8 will be described with reference to FIGS. 6A and 6B.

FIG. 6A shows a ray diagram when the light shielding film 8 is not provided. Incident light 31 emitted from the subject passes through the lens la, passes through the optical filter 2a, and forms an image on the original imaging region 4a. Similarly, the incident light ray 33 emitted from the subject passes through the lens lb, passes through the optical filter 2a, and returns to the original imaging area. Forms an image in area 4b. However, incident light 32 from a subject that has a large incident angle and does not necessarily need to be imaged passes through lens la and filter 2a in order, and forms an image as unnecessary light in imaging area 4b that does not correspond to lens la. Will deteriorate. Like the incident light beam 32, the incident light beam 34 having a large incident angle and having a large incident angle passes through the lens lb, and is then shielded by the outer cylindrical portion 62 and does not form an image.

FIG. 6B shows a ray diagram when the light shielding film 8 is provided. In the same way as in FIG. 6A, incident rays 31 and 33 emitted from the subject normally form images in the original imaging areas 4a and 4b, respectively. On the other hand, the incident light beam 32 from the object passes through the lens la and is then shielded by the light shielding film 8 disposed on the optical filter module 2, thereby preventing the incident light 32 from being imaged as unnecessary light. It becomes possible. The incident light beam 34 from the subject passes through the lens lb after being passed through the lens lb as in FIG.

[0037] In FIG. 6A above, when the common filter 2a is provided for the adjacent lenses la and lb, the light that has passed through the lens la passes through the filter 2a, and then the image corresponding to the lens lb. The example of entering the region 4b has been described. However, even when the adjacent filters la and lc are provided with separate filters 2a and 2c, respectively, and the light shielding wall 64 (see FIG. 4C) is provided between the filters 2a and 2c, the lens It may enter the imaging area 4c corresponding to the light power lens lc that has passed through la.

[0038] Similar to the light blocking block 6, the light blocking film 8 includes light blocking portions 81a to 81d arranged in a cross shape so as to form four independent openings 8a to 8d, as shown in FIG. And an outer frame portion 82 for holding the light shielding portions 81a to 81d. The light shielding portions 81a to 81d extend radially with respect to the Z axis, which is the central axis of the light shielding block 6, the light shielding portions 81a and 81c are along the XZ plane, and the light shielding portions 81b and 8 Id are along the YZ plane. Yes. The four openings 8a to 8d are arranged on the optical axes of the four lenses la to ld, respectively. The four openings 8a to 8d have the same or slightly smaller opening area than the four openings 61a to 61d formed in the light blocking block 6. The light shielding film 8 is formed on the light shielding block 6 by fitting two concave portions (notches) 83 provided on the outer frame portion 82 to two convex portions 611 (see FIG. 4A) provided on the light shielding block 6. The positioning is fixed.

[0039] In order to measure the distance to the subject with the camera module configured as described above Performs the following operations. Two images of the same wavelength, that is, two imaging areas 4a and 4b or two images obtained from the two imaging areas 4c and 4d are compared, and arithmetic processing such as block matching is performed. The amount of parallax of the corresponding subject image existing in is obtained. Next, the distance to the subject can be measured from the parallax amount based on the principle of triangulation.

[0040] However, an error occurs in the amount of parallax obtained by calculation due to assembly variation. The main factors that cause errors are the relative tilt of the lens array 1 with respect to the imaging device 4, the tilt of the optical filters 2a and 2c, the focus shift, and the position of the lens array 1 in the direction perpendicular to the Z axis of the light blocking block 6. There is a gap.

Therefore, in this embodiment, the three reference surfaces 65 provided on the light shielding block 6 are brought into direct contact with the surface of the imaging element 4 in the Z-axis direction, and the four reference surfaces 65 provided on the lens array 1 are provided. The reference surface 14 is brought into direct contact with the four reference surfaces 68 provided on the light blocking block 6 in the Z-axis direction. As a result, the relative tilt of the lens array 1 with respect to the image sensor 4 is suppressed to the value of parallelism between the plane including the three reference surfaces 65 and the plane including the four reference surfaces 68 provided in the light shielding block 6. be able to. Further, by adopting the above-described configuration, the deviation of the focal point of the lens la˜: Ld in the Z-axis direction with respect to the light receiving surfaces of the corresponding imaging regions 4a to 4d is different from the reference surface 65 and the reference surface 68 of the light shielding block 6. It is possible to suppress the distance accuracy between the values. Further, since the lenses la to Id are integrally formed, the flange back difference between the lenses that allow light of the same wavelength band to pass through can be made extremely small. As a result, the error amount of the generated parallax can be ignored.

In the present embodiment, the optical filters 2 a and 2 c are brought into direct contact with the reference surface 612 provided in the light shielding block 6 in the Z-axis direction. Thus, as with the lens array 1, the tilt of the optical filters 2a and 2b with respect to the image sensor 4 can be suppressed. Therefore, the error amount of the parallax generated due to the tilt of the optical filters 2a and 2c is very small and can be ignored.

In order to further suppress an error amount of parallax due to the tilt of the optical filter, an optical filter corresponding to a plurality of lenses optimally designed for the same wavelength band light is integrally formed. For example, two optical filters are applied to two lenses la and lb that are optimally designed for green light. Images can be obtained even if provided separately. However, if an optical filter is provided for each lens individually, each optical filter may tilt in a different direction and angle due to assembly variations. In such a case, a large error in the amount of parallax for measuring the distance can occur. Will occur. On the other hand, if one optical filter integrated with a plurality of lenses optimally designed for the same wavelength band light is provided as in this embodiment, the optical filter tilts at the time of assembly. Even so, the two images that are compared to determine the parallax change in the same way due to this tilt, so the parallax error caused by the tilt is very small and can be ignored.

Furthermore, the lens array 1 is positioned in the X-axis direction with respect to the light shielding block 6 by directly contacting the reference surface 67 provided on the lens array 1 with the reference surface 67 provided on the light shielding block 6. The lens array 1 is positioned in the Y-axis direction with respect to the light shielding block 6 by directly contacting the reference surface 13 provided on the lens array 1 with the reference surface 66 provided on the light shielding block 6. The As a result, the optical axis of the lens la to ld and the center of the openings 6a to 6d of the light blocking block 6 are matched, so that the light passing through the lens la to Ld is blocked by the light blocking wall 6 la to 6 Id and the outside. It is possible to prevent a part of the subject image from being incident on the inner wall surface of the cylindrical part 62 and forming a part of the subject image in the imaging regions 4a to 4d, or the reflected light to enter the imaging regions 4a to 4d as unnecessary light. . Therefore, the parallax error caused by these is very small and can be ignored.

[0045] When an optical filter is individually provided for each lens, the light shielding wall 64 can be provided between adjacent optical filters, and generation of stray light or the like (see FIG. 6A) can be prevented to some extent. However, when one optical filter integrated with a plurality of lenses is provided, the light shielding wall 64 cannot be provided at a position corresponding to the boundary between adjacent imaging regions. Therefore, in this case, as described above, it is particularly desirable to provide the light shielding film 8 on the optical filter.

FIG. 8A shows a plan view of the camera module of the present embodiment. FIG. 8B shows a cross-sectional view taken along the line 8B-8B in FIG. 8A. As shown in FIG. 8B, the imaging surface (upper surface) of the imaging device 4 serving as a reference surface is in contact with the reference surface 65 provided on the light shielding block 6, and the reference surface 14 provided on the lens array 1 is shielded from light. The reference surface 68 provided on the block 6 comes into contact, When the optical filter module 2 and the reference surface 612 provided on the light shielding block 6 come into contact with each other, the imaging device 4, the light shielding block 6, the lens array 1, and the optical filter module 2 are positioned in the Z-axis direction, and the imaging device It is obvious that the tilt of the lens array 1 and the optical filter module 2 with respect to 4 is suppressed.

[0047] As described above, according to the first embodiment of the present invention, even when simple assembly is performed without using a complicated and expensive adjustment mechanism at the time of assembly, it occurs when measuring the distance to the subject. Therefore, the measurement error can be made extremely small and the measurement distance accuracy can be improved.

[0048] In the above embodiment, the four imaging regions are almost equally divided regions. The optical system of the present invention is not limited to this. For example, non-uniform regions in consideration of generated parallax It may be. It is also possible to set the imaging area so that the measurement distance accuracy can be improved as much as possible by making the best use of the effective pixel area of the imaging device 4 and widening the distance between the lenses as much as possible. The above effect of the form can be obtained.

[0049] Further, since a plurality of lenses are integrally molded in the lens array 1, the linear expansion coefficient is uniform. Therefore, if the lens array 1 is made as symmetrical as possible, the shape against the temperature change is obtained. The change of becomes uniform. Therefore, by detecting the temperature using a thermistor or the like, the distance between the lenses at each temperature can be estimated, and the change in the optical axis position of each lens can be estimated. As a result, it is possible to correct the amount of parallax due to temperature changes and ensure the measurement distance accuracy.

[0050] (Embodiment 2)

FIG. 9 is an exploded perspective view of the compound-eye camera module according to Embodiment 2 of the present invention. Only the configuration of the light shielding block 6 is different from the first embodiment. In the light shielding block 6 of the present embodiment, the light shielding walls 6 la to 6 Id and the outer cylindrical portion 62 are configured separately. Light shielding portions 661a to 661d are integrally formed on the light shielding walls 61a to 61d, respectively. Further, a reference surface (first reference surface) 68 that contacts the reference surface 14 of the lens array 1 is formed integrally with the light shielding portions 661b to 661d, and a reference surface (third third surface) that contacts the reference surface 12 of the lens array 1 is formed. (Reference surface) 67 is formed integrally with the light shielding portion 661a, and a reference surface (fourth reference surface) 66 that is in contact with the reference surface 13 of the lens array 1 is formed integrally with the light shielding portion 661d. Contact Reference surface (fifth reference surface) 612 is formed integrally with the light shielding parts 661a to 661d, and a reference surface (second reference surface) 65 that contacts the imaging element 4 is formed integrally with the light shielding walls 61a to 61d. It has been done. Then, the imaging device 4 is brought into contact with the reference surface 65, and the lens array 1 and the optical filter module 2 are brought into contact with the reference surface 68 and the reference surface 612, respectively, so that the imaging device 4, the light shielding block 6, and the lens array 1 are brought into contact. The optical filter module 2 is positioned and fixed in the Z-axis direction. At the same time, the lens array 1 is brought into contact with the reference surfaces 67 and 66, and the lens array 1 is positioned and fixed in a direction perpendicular to the Z axis.

FIG. 10 shows a cross-sectional view of a compound-eye camera module excluding the outer cylindrical portion 62 of the light shielding block 6. As is clear from FIG. 10, it is the reference surface 65 that positions the image sensor 4 in the Z-axis direction, and it is the reference that positions the lens array 1 and the optical filter module 2 in the Z-axis direction. It can be seen that surface 68 and reference surface 612.

[0052] Then, the light shielding block 6 is assembled by extrapolating and fitting the outer cylindrical portion 62 to the light shielding portions 66la to 66Id. The outer cylindrical portion 62 of the light shielding block 6 is provided for the purpose of preventing the light beam that does not pass through each lens from forming an image on the imaging region, and suppresses tilt, focus shift, etc. of each component constituting the optical system. Unlike Embodiment 1, this is performed by the light shielding walls 61a to 61d and the light shielding parts 661a to 661d.

[0053] With the above configuration, as in the first embodiment, the relative tilt and defocus of the lens array 1 and the optical filters 2a and 2c with respect to the image sensor 4 and the Z axis of the lens array 1 with respect to the light shielding block 6 are as follows. Displacement in a direction orthogonal to the direction can be suppressed. Therefore, even if simple assembly is performed without using a complicated and expensive adjustment mechanism at the time of assembly, the error generated when measuring the distance to the subject can be extremely reduced, and the measurement distance accuracy can be improved. Becomes pretty.

[Embodiment 3]

FIG. 11 shows an exploded perspective view of the main components of the compound eye camera module according to Embodiment 3 of the present invention. In FIG. 11, the difference from the first embodiment is only the lens array 1, the optical filter module 2, and the light shielding walls 61a to 61d. The upper barrel 5 and the outer cylinder 62, which are components of the light shielding block 6, and the substrate 3 having the same functions as those of the first and second embodiments are not shown. A reference plane 14 for positioning and fixing the lens array 1 with respect to the image sensor 4 in the Z-axis direction is provided in a region of the lens array 1 facing the optical filter module 2. The optical filter module 2 is composed of four optical filters 2a to 2d. The optical filters 2a and 2b transmit only light in the same wavelength band, and the optical filters 2c and 2d only transmit light in the same wavelength band. Permeate. In one embodiment, the optical filters 2a and 2b transmit only light in the green wavelength band, and the optical filters 2c and 2d transmit only light in the near-infrared wavelength band.

[0056] A reference surface (first reference surface) 68 that comes into contact with the reference surface 14 of the lens array 1 is provided on the upper end surface of the wall surface 64 in which the light shielding walls 61a to 6 Id extend in the Z-axis direction toward the lens array 1 side. It has been. A reference surface (third reference surface) 67 that contacts the reference surface 12 of the lens array 1 is integrally formed with the light shielding wall 61a, and a reference surface that contacts the reference surface 13 of the lens array 1 (fourth reference surface) 66. Is formed integrally with the light shielding wall 61d, and a reference surface (second reference surface) 65 that comes into contact with the image sensor 4 is formed integrally with the light shielding walls 6la to 61d. A reference surface (fifth reference surface) 612 that contacts the optical filters 2a to 2d is provided on the light shielding walls 61a to 61d.

[0057] Fig. 12 shows a cross-sectional view to explain the mutual relationship between the components. As in the second embodiment, the reference surface 65 of the light shielding walls 61a to 61d is brought into contact with the imaging element 4. Then, using the light shielding walls 61a to 61d as a reference, the optical filters 2a to 2d are brought into contact with a reference surface 612 provided on the light shielding walls 61a to 61d, and the optical filters 2a to 2d are positioned and fixed in the Z-axis direction. Then, the reference surface 14 of the lens array 1 is brought into contact with a reference surface 68 provided on the light shielding walls 61a to 61d, and the lens array 1 is positioned and fixed in the Z-axis direction. At the same time, the reference surface 12 and the reference surface 13 of the lens array 1 are brought into contact with the reference surface 67 provided on the light shielding wall 61a and the reference surface 66 provided on the light shielding wall 61d, respectively, so that the lens array 1 is orthogonal to the Z axis. Position in the direction.

[0058] With the above configuration, as in the first and second embodiments, the lens array 1 and the optical filters 2a to 2d with respect to the image sensor 4 are relatively tilted, defocused, and the Z of the lens array 1 with respect to the light blocking block 6 is Z. The positional deviation in the direction orthogonal to the axis can be suppressed. Therefore, even if simple assembly is performed without using a complicated and expensive adjustment mechanism at the time of assembly, the error that occurs when measuring the distance to the subject can be extremely reduced and the measurement distance accuracy can be improved. Is possible. Further, since the wall surface 64 on the light shielding walls 61a to 61d is in contact with the lens array 1, the light beam 32 described in FIG. 6A collides with the wall surface 64. Therefore, in the present embodiment, the light shielding film 8 between the lens array 1 and the optical filter module 2 can be omitted. Therefore, the cost can be reduced.

[0060] (Embodiment 4)

A modification of the configuration of the optical filter that selectively transmits light of subject power will be described below with reference to the drawings.

[0061] Fig. 13 shows a case where light in the visible light region needs to be imaged in the imaging regions 4a and 4b by blocking light in the near infrared and lower frequencies (hereinafter simply referred to as "near infrared light"). FIG. 3 is an exploded perspective view of the camera module. When photographing light in the visible light region that does not include near-infrared light among light with strong subject power, it is necessary to provide an optical filter that blocks near-infrared light. For example, in the camera module described in Embodiment 1, in order to prevent near-infrared light from entering the imaging regions 4a and 4b, the near-infrared light is applied to the optical filter 2a that transmits green light. What is necessary is just to overlap and form the optical filter to interrupt. However, in order to manufacture more inexpensively, as shown in FIG. 13, only the region 9a corresponding to the optical filter 2a of the base material (for example, a transparent glass substrate) 9 provided separately from the optical filter 2a is provided. It is preferable to form an IR filter that blocks near infrared light. In this case, the optical filter function is not given to the region 9c of the base material 9 corresponding to the optical filter 2c that transmits near-infrared light. The substrate 9 is positioned in the Z-axis direction by contacting the optical filter module 2. In this example, the light shielding film 8 is provided between the lens array 1 and the substrate 9.

Unlike FIG. 13, the base material 9 may be disposed between the optical filter module 2 and the light shielding block 6. In this case, the base material 9 comes into contact with the reference surface 612. The light shielding film 8 is provided between the lens array 1 and the optical filter module 2.

The camera module shown in FIG. 14 uses the light shielding block 6 in which the light shielding walls 6 la to 6 Id that divide the imaging region and the outer cylindrical portion 62 are separate from each other as in FIG. Different from the camera module shown in Fig.13.

The camera module shown in FIG. 15 is provided between the light shielding film 8 force lens array 1 and the base material 9 on which the IR filter 9a is formed, and between the base material 9 and the optical filter module 2. This is different from the camera module shown in FIG. When the IR filter 9a is formed on the base material 9 different from the optical filter module 2, the total thickness of the base material 9 and the optical filter module 2 is increased. Therefore, in the configuration shown in FIG. There is a high possibility that light from the light enters the imaging area that does not correspond to the lens that has passed through. In order to prevent this, a two-layer light shielding film 8 is provided as shown in FIG. Thereby, it is possible to prevent unnecessary light that has passed through the lens corresponding to the imaging area from entering each imaging area. As a result, it is possible to prevent the measurement distance accuracy from deteriorating.

The camera module shown in FIG. 16 is different from the camera module shown in FIG. 13 in that the base material 9 on which the IR filter 9a is formed is provided closer to the subject than the upper lens barrel 5. The parts that make up the optical system, such as the lens module 7 and the light-blocking block 6, may be broken when touched directly by the user, so the camera module is covered with a camera chassis (not shown). However, in order to capture light from the subject, the portion of the lens module 7 including the apertures 5a to 5d needs to expose the camera chassis force. In this case, it is preferable that the lens module 7 is covered with a highly transparent protective cover in order to prevent the user from directly touching the exposed portion. In FIG. 16, the base material 9 on which the IR filter 9a is formed is used as a protective cover for preventing the user from directly touching the camera module. As a result, the number of parts can be reduced and the thickness of the camera module can be reduced as compared with the case where a protective cover is provided separately from the base material 9.

[0066] In any of the camera modules described above, the optical filter module 2 is used so that each of the imaging regions 4a to 4d images light of a specific wavelength band. The camera module shown in FIG. 17 is different from the above-described camera modules in that the optical filter module 2 is used! In FIG. 17, each of the imaging regions 4 a to 4 d images light in all wavelength bands in which the imaging element 4 has sensitivity. By not using the optical filter module 2, an inexpensive camera module can be provided. Further, by not using the optical filter module 2, the gap between the lens array 1 and the light shielding walls 61a to 61d can be reduced. This can reduce the possibility of unnecessary light described with reference to FIG. 6A. Accordingly, the light shielding film 8 is also omitted in the camera module of FIG. Thereby, an inexpensive camera module can be provided. [0067] In the above description, the optical filters (optical filters 2a, 2b, 2c, 2d and IR filter 9a) that selectively transmit light in a specific wavelength band are formed on a base material (for example, a transparent glass substrate). However, the present invention is not limited to this. For example, in the case where an optical filter may be formed directly on the image sensor 4, the same effect as described above can be obtained. When an optical filter is formed on the image sensor 4, an optical filter having the same characteristics may be formed on all pixels in one imaging area, but each color light of red, green, and blue is selectively transmitted. Optical filters may be arranged in a bay array on the pixels in the imaging area. A color image can be obtained by arranging the optical filters in such a Bayer arrangement. For example, the effective pixel area of the imaging element 4 is divided into four imaging areas as described above, and optical filters are arranged in a Bayer array in two of the imaging areas, and near red in the remaining two imaging areas. You may arrange | position the optical filter which permeate | transmits external light on all the pixels.

[0068] In the camera module described above, the effective pixel area of the imaging element 4 is divided into four imaging areas, but the number of imaging areas, the arrangement of a plurality of imaging areas, and the like can be changed as appropriate.

[0069] The optical filter module 2 described above is composed of a plurality of components separately created for each wavelength band of light to be transmitted (for example, green light and near-infrared light). It is not limited to. For example, it may be composed of a single component in which optical filters having different characteristics (for example, a green optical filter and a near infrared optical filter) are formed in different regions of a common base material.

[0070] The light shielding film 8 is a force provided separately from the optical filter 2 and the substrate 9. The present invention is not limited to this. For example, in the case where the light shielding film 8 may be directly formed on the optical filter 2 and the substrate 9 using printing or the like, the same effect as described above can be obtained.

[0071] In the camera module described above, two reference surfaces that are in contact with each other to suppress tilt and the like are flat surfaces, and the force that the two planar reference surfaces are in surface contact with each other. The present invention is not limited thereto. Not. For example, the planar reference surface and the spherical reference surface may be brought into point contact, or the planar reference surface and the bowl-shaped reference surface may be brought into line contact. For example, the reference surface (second reference surface) that contacts the image sensor 4 may be composed of three spherical surfaces 65R on which fillets are formed as shown in FIG. This part is also used to position the part in one direction. The number of reference surfaces provided on the product is not limited to the above-described embodiment, and can be changed as appropriate.

[0072] The embodiments described above are intended to clarify the technical contents of the present invention, and the present invention is to be interpreted as being limited to such specific examples. However, various modifications may be made within the spirit and scope of the invention described in the claims, and the present invention should be interpreted broadly.

Industrial applicability

[0073] The field of application of the compound eye camera module of the present invention is not particularly limited, but it is preferably used for, for example, a small-sized and thin mobile phone having a camera function, a digital still camera, a surveillance camera, an in-vehicle camera, and the like. can do.

Claims

The scope of the claims

[1] A lens array having a plurality of lenses having different optical axes arranged on a single plane, and an imaging element having a plurality of imaging areas corresponding to each of the plurality of lenses,

A light-shielding block that is disposed between the lens array and the image sensor and has a plurality of openings corresponding to the lenses on a one-to-one basis,

The shading block is in contact with the lens array and has a first reference surface for positioning the lens array in the optical axis direction, and a second reference surface that is in contact with the imaging element and positions the imaging element in the optical axis direction. A surface, a third reference surface that contacts the lens array and positions the lens array in a first direction orthogonal to the optical axis, and abuts the lens array to align the lens array with the optical axis and the first direction. A compound-eye camera module having a fourth reference surface positioned in a second direction orthogonal to the first direction.

[2] The optical filter module is further disposed between the lens array and the imaging device, and transmits light in a specific wavelength band among light transmitted through the plurality of lenses. The compound-eye camera module according to claim 1, further comprising a fifth reference surface that abuts on the optical filter module and positions the optical filter module in the optical axis direction.

[3] It further includes a light shielding film disposed between the lens array and the optical filter module and having a plurality of openings corresponding to each of the plurality of lenses in a one-to-one relationship. 2. The compound-eye camera module according to claim 1, wherein the sizes of the plurality of openings are the same as or smaller than the plurality of openings of the light shielding block.