WO2014200008A1 - Imaging device - Google Patents

Abstract

Provided is an imaging device capable of suppressing the deterioration in the optical performance of a lens array stack due to a change in the ambient temperature and enabling highly accurate imaging. First to third lens arrays (10, 20, 30) constituting the lens array stack are formed of a resin material using a molding die, and thus the lens arrays (10, 20, 30) tend to warp due to the influence of temperature. However, the lens arrays (10, 20, 30) are bonded at the supports (10b, 20b, 30b) between the adjoining lenses (10a, 20a, 30a) via spacers (40, 50) as coupling members, and thus it is possible to reduce the warping of the lens array stack (200) and suppress local degradation in the image-forming performance of a compound-eye optical system (100), thereby enabling highly accurate imaging.

Description

Imaging device

The present invention relates to an imaging apparatus including a laminated lens array, and more particularly to an imaging apparatus for reconstructing one image from images obtained by a plurality of single-eye optical systems constituting the laminated lens array.

In order to respond to the recent demand for thinning of the imaging optical system, attempts have been made to improve manufacturing accuracy corresponding to the shortening of the overall length by optical design and the accompanying increase in error sensitivity. However, there is a demand for further thinning and high performance, and it has become insufficient to obtain an image with one lens system and a sensor array as in the past. Therefore, an image pickup apparatus that divides a sensor array region, arranges an optical system corresponding to each of the regions, and processes the obtained image to output a final image meets the demand for thinning. It is attracting attention from a viewpoint.

On the other hand, in the imaging apparatus, it is considered to use a stacked lens array in which a plurality of lens arrays are stacked in the optical axis direction and each individual lens is composed of a plurality of lenses in order to improve image quality. It is done. Further, it is conceivable to form a lens array with few interfaces by integrally forming the lens portion and the surrounding support portion with an optical material such as resin. Patent Document 1 discloses a structure in which a plurality of lens arrays integrally formed of plastic are stacked.

However, when the lens array is formed of a plastic material, if the environmental temperature change around the lens array is large, the lens array expands and contracts due to the environmental temperature change, resulting in a relatively large warp in each lens array there's a possibility that. In particular, as in Patent Document 1, when a plurality of lens arrays are cemented at the outer periphery of the lens array, distortion is concentrated on a specific lens array, which may cause a large deformation. Such a lens array deformation has a difference in image formation state between the central side and the peripheral side among a plurality of single-eye optical systems, and the optical performance of the single-eye optical system varies. May cause unique problems.

In Patent Document 2, a lens is a laminated type in which a plurality of lens arrays are joined by spacers provided with a plurality of openings at positions corresponding to the lenses. An array is described.

However, Patent Document 2 does not describe the deformation of the laminated lens array due to the environmental temperature change when the laminated lens array is used without being separated into individual lenses. In addition, in an imaging device using a lens array made of an integrated optical material, it is necessary to prevent the images of adjacent single-eye optical systems from overlapping, or to propagate through the lens array to the adjacent single-eye optical system. Although it is required to prevent light from entering, Patent Document 2 does not consider this. In order to prevent optical interference or crosstalk in such a lens array, when a light shielding member or a light absorbing member is arranged, another member is added in the optical axis direction in addition to a plurality of lens arrays and spacers. Therefore, it becomes disadvantageous for thinning of the apparatus.

JP 2000-227505 A JP 2011-65040 A

The present invention has been made in view of the above-described background art, and prevents the optical performance of the lens array laminate from deteriorating due to a change in environmental temperature while ensuring good optical performance without being too thick. An object of the present invention is to provide an imaging apparatus that can perform high-accuracy imaging.

In order to achieve the above object, an imaging apparatus according to the present invention includes a plurality of first lens portions and a resin-made first lens that has a first support portion that supports the plurality of first lens portions from the periphery. An optical axis direction of the array and the resin-made second lens array having a plurality of second lens portions and a second support portion supporting the plurality of second lens portions from the periphery via a connecting member. A lens array laminate, a sensor array on which a plurality of images are formed by the lens array laminate, and an image processing unit that creates a reconstructed image from the plurality of images obtained by the sensor array, The first and second lens arrays have a plurality of first lens portions and a plurality of second lens portions facing each other, and the first of the connecting members between the adjacent first lens portions of the first support portion. Bonded with the face of The second lens portion adjacent to the second support portion is joined to the second surface of the connecting member, and the connecting member is made of a material having a smaller linear expansion coefficient than the first and second lens arrays. And it has the function to suppress the optical interference between the some synthetic lenses comprised by the 1st and 2nd lens part. Here, when there are three or more lens arrays constituting the lens array stacked body, the adjacent lens arrays are used as the first and second lens arrays, respectively.

In the imaging device, even if the ambient temperature changes, the first and second lens arrays are joined by the connecting member having a small linear expansion coefficient at the support portion between the adjacent lens portions. It is possible to reduce the curvature of the body and suppress local deterioration of the imaging performance of each individual eye optical system. Accordingly, it is possible to suppress deterioration of the optical performance of the lens array laminate due to a change in the environmental temperature, and it is possible to perform highly accurate imaging. In addition, since the connecting member has a function of suppressing optical interference or crosstalk between the plurality of synthetic lenses configured by the first and second lens portions, the thickness does not become too large and is good. Optical performance can be ensured.

In another aspect of the present invention, in the imaging apparatus, the connecting member is formed of any one of glass, metal, and ceramics.

In yet another aspect of the present invention, the connecting member has light shielding properties.

In yet another aspect of the present invention, the connecting member is subjected to a surface treatment that reduces transmission or reflection.

In yet another aspect of the present invention, the connecting member is bonded to the first and second lens arrays with an adhesive having a light shielding property.

In yet another aspect of the present invention, the connecting member is a plate-like member having a light transmitting portion corresponding to a plurality of lens portions.

In yet another aspect of the present invention, the light transmission part has a contour corresponding to the effective light flux cross section.

In still another aspect of the present invention, a gap is provided between at least one of the first and second lens arrays and the connecting member so as to form a ventilation path communicating with a space where the plurality of first and second lens portions face each other. ing.

In yet another aspect of the present invention, the connecting member has a groove at a position corresponding to the gap. In this case, the ventilation path can be easily formed.

In yet another aspect of the present invention, the second lens array is disposed between the sensor array and the sensor array is fixed to the second support portion between the adjacent second lens portions of the second lens array and the sensor array. The connecting member is further provided.

1A and 1B are a plan view and a side sectional view for explaining the imaging apparatus of the first embodiment. It is a partial expanded sectional view of an imaging device. It is a figure explaining the front side of the 2nd lens array. It is a figure explaining the front side of a 3rd lens array. 5A and 5B are perspective views for explaining the effect of heating the compound-eye optical systems of Examples and Comparative Examples. FIG. 6A is a side cross-sectional view illustrating an imaging apparatus according to the second embodiment, and FIG. 6B is a partially enlarged cross-sectional view of the imaging apparatus. It is a partial expanded sectional view explaining the imaging device of the modification of 2nd Embodiment. 8A to 8C are views for explaining the shape of the spacer which is a connecting member. FIG. 9A is a plan view for explaining a part of a compound eye optical system in the imaging apparatus of the third embodiment, and FIG. 9B is a side sectional view for explaining formation of a gap.

[First Embodiment]
As shown in FIGS. 1A and 1B, the imaging apparatus 1000 according to this embodiment includes a compound eye optical system 100, a sensor array 81 having a plurality of sensor elements provided corresponding to a plurality of lens units, and an image processing unit 85. With.

The compound-eye optical system 100 includes a lens array stack 200 in which a plurality of lens arrays 10, 20, 30 and a plurality of spacers 40, 50 are alternately stacked in the Z direction, and an IR cut filter is provided on the image side in the −Z direction. 60 is attached. In the compound eye optical system 100, the first to third lens arrays 10, 20, and 30 are flat members extending in parallel to the XY plane perpendicular to the Z axis, and the first and second spacers 40 and 50 are The connecting member extends along the first to third lens arrays 10, 20, and 30 therebetween. Each spacer 40, 50 has a smaller linear expansion coefficient than any of the lens arrays 10, 20, 30, and has a relatively high rigidity. The compound eye optical system 100 is housed in a rectangular frame-shaped case 100a having a light shielding property.

As shown in FIG. 1A, FIG. 2, etc., the first lens array 10 on the object side in the compound eye optical system 100 is a molded product made of a thermoplastic resin and has a square outline in plan view. The first lens array 10 is formed by, for example, injection molding using a side gate type mold. The first lens array 10 includes a plurality of lens portions 10a each of which is an optical element, and a support portion 10b that supports the plurality of lens portions 10a from the periphery. The plurality of lens portions 10a constituting the first lens array 10 are two-dimensionally arranged on square lattice points (16 × 4 × 4 in the illustrated example) arranged in parallel to the XY plane. Each lens unit 10a has a first optical surface 11a that is convex on the first main surface 10p on the object side, and a second optical surface 11b that is concave on the second main surface 10q on the object side. Both optical surfaces 11a and 11b are aspherical surfaces, for example. The support portion 10b is a flat plate-like flat portion, and includes a plurality of peripheral portions 10c so as to surround each lens portion 10a. Each peripheral portion 10c has a flange surface 11c on the object side, that is, the first optical surface 11a side, and a flange surface 11d on the second optical surface 11b side. As shown in FIG. 1A, the outside of the plurality of surrounding portions 10c of the first lens array 10 includes a rectangular lattice-shaped joint AS1 indicated by a one-dot chain line. The joining portion AS1 is a portion for joining the first lens array 10 to the first spacer 40. In addition, joining with the 1st spacer 40 can also be performed only in boundary part AT1 (dotted hatching part) between the lens parts 10a except the outer frame among joining part AS1.

The second lens array 20 on the image side shown in FIGS. 2 and 3 is a molded product made of a thermoplastic resin produced in the same manner as the first lens array 10 and has a square outline in plan view. The second lens array 20 includes a plurality of lens portions 20a each of which is an optical element, and a support portion 20b that supports the plurality of lens portions 20a from the periphery. The plurality of lens portions 20a are two-dimensionally arranged on square lattice points (16 × 4 × 4 in the illustrated example) arranged in parallel to the XY plane. Each lens unit 20a has a first optical surface 21a that is concave on the first main surface 20p on the object side, and a second optical surface 21b that is convex on the second main surface 20q on the image side. Both optical surfaces 21a and 21b are aspherical surfaces, for example. The support portion 20b is a flat plate-like flat portion, and includes a plurality of peripheral portions 20c so as to surround each lens portion 20a. Each peripheral portion 20c has a flange surface 21c on the object side, that is, the first optical surface 21a side, and a flange surface 21d on the second optical surface 21b side. As shown in FIG. 3, the outside of the plurality of peripheral portions 20c of the second lens array 20 is a thin portion 20r, and includes a rectangular lattice-shaped joint portion AS2 indicated by a one-dot chain line. The joining portion AS2 is a portion for joining the second lens array 20 to the first and second spacers 40 and 50. It should be noted that the first and second spacers 40 and 50 can be joined only at the boundary portion AT2 (dotted hatching portion) between the lens portions 20a excluding the outer frame in the joint portion AS2.

As shown in FIG. 3, a shallow recess 20r1 is formed inside the peripheral portion 20c of the second lens array 20 so as to surround the first optical surface 21a, and an annular diaphragm 25 formed of metal or other light shielding body. Is held in the recess 20r1. The aperture 25 is concentric with the first optical surface 21a and has, for example, a circular opening 25a. By making the outer shape of the diaphragm 25 circular, it becomes a point-symmetrical shape, so that the diaphragm 25 can be easily arranged with respect to the second lens array 20.

The third lens array 30 on the image side shown in FIGS. 2, 4 and the like is a molded product made of a thermoplastic resin produced in the same manner as the first lens array 10, and has a square outline in plan view. The third lens array 30 includes a plurality of lens portions 30a, each of which is an optical element, and a support portion 30b that supports the plurality of lens portions 30a from the periphery. The plurality of lens portions 30a are two-dimensionally arranged on square lattice points (16 × 4 × 4 in the illustrated example) arranged in parallel to the XY plane. Each lens unit 30a has a concave first optical surface 31a on the first main surface 30p on the object side, and a convex and concave second optical surface 31b on the second main surface 30q on the image side. Both optical surfaces 31a and 31b are aspherical surfaces, for example. The support portion 30b is a flat plate-like flat portion, and includes a plurality of peripheral portions 30c so as to surround each lens portion 30a. Each peripheral portion 30c has a flange surface 31c on the object side, that is, the first optical surface 31a side, and a flange surface 31d on the second optical surface 31b side. As shown in FIG. 4, the outside of the plurality of peripheral portions 30c in the third lens array 30 is a thin portion 30r, and includes a rectangular lattice-shaped joining portion AS3 indicated by a one-dot chain line. The joining portion AS3 is a portion for joining the third lens array 30 to the second spacer 50. In addition, joining with the 2nd spacer 50 can also be performed only in boundary part AT3 (dotted hatching part) between the lens parts 30a except the outer frame among joining part AS3.

On the peripheral portion 30c of the third lens array 30, an annular stop 35 formed of a metal or other light shielding member is supported and surrounded by a spacer body 51 of a second spacer 50 described later. The diaphragm 35 is concentric with the first optical surface 31a and has, for example, a rectangular opening 35a.

The first spacer 40 (connecting member) is a plate-like member formed of glass, ceramics, metal, resin, or the like having a lower linear expansion coefficient than the lens arrays 10, 20, and 30. And a shape corresponding to the joint AS2 of the second lens array 20. The first spacer 40 is held so as to be fitted into the thin portion 20r formed in the second lens array 20. The first spacer 40 is bonded to the second main surface 10q on the image side of the first lens array 10 by the adhesive 8 on one end surface (first surface) or the first main surface 40a side, and the other At the end surface (second surface) or the main surface 40b side of the second lens array 20, it is bonded to, for example, the bottom portion, the side wall, or the bottom portion and the side wall of the thin portion 20r of the object of the second lens array 20. The first spacer 40 has a spacer main body 41 and an opening 42 (light transmission part). The spacer main body 41 is a lattice frame-shaped part, and the opening 42 has a rectangular shape. The opening 42 is formed as a through hole at a position corresponding to the lens portion 10a and the like. The lens portion 10a of the first lens array 10 and the lens portion 20a of the second lens array 20 are indirectly related to the axis AX direction and the direction perpendicular thereto by a rectangular frame (a part of the spacer body 41) around the opening 42. It will be supported. Materials such as glass, ceramics, metal, and resin used for the first spacer 40 have a sufficiently low coefficient of thermal expansion and relatively high rigidity, so that the effect of suppressing warpage of the first and second lens arrays 10 and 20 is high. . Note that the linear expansion coefficient of the resin constituting the first and second lens arrays 10 and 20 is about 60 to 70 ppm [1 / ° C.] in the application of the compound-eye optical system 100. On the other hand, when the first spacer 40 is glass, its expansion coefficient is about 3 to 13 ppm [1 / ° C.], and when the first spacer 40 is metal, its expansion coefficient is 10 to 25 ppm [1 / ° C. When the first spacer 40 is ceramic, the expansion coefficient can be about 2.5 to 10 ppm [1 / ° C.].

The first spacer 40 is formed of, for example, a black or dark material, but is not necessarily limited thereto, and can be formed of various materials, for example, a light transmissive material. When the first spacer 40 is formed of a light transmitting material, from the viewpoint of preventing stray light, a roughening process is performed to reduce reflection, a black or dark color coating or layer formation is performed, a black or dark color is applied. The first and second lens arrays 10 and 20 are bonded with the adhesive 8. By performing a surface treatment for reducing transmission or reflection on the first spacer 40, it is possible to have a function of blocking incident light regardless of the material of the first spacer 40. Further, since the adhesive 8 has a light shielding property, the adhesive 8 can prevent the passage of incident light regardless of the material of the first spacer 40. From the above, the degree of freedom in selecting the material of the connecting material increases. In the present embodiment, since the first spacer 40 is a single body, the rigidity of the lens array laminate 200 can be increased, and the assembly is easy. These points also apply to the spacer 50 described later.

The second spacer 50 (connecting member) is a plate-like member formed of glass, ceramics, metal, resin, or the like having a lower linear expansion coefficient than the lens arrays 10, 20, 30. And a joint portion AS3 of the third lens array 30. The second spacer 50 is held so as to be fitted into the thin portion 30 r formed in the third lens array 30. The second spacer 50 is bonded to the second main surface 20q on the image side of the second lens array 20 by the adhesive 8 on one end surface (first surface) or the first main surface 50a side, and the other At the end surface (second surface) or the second main surface 50b side, the adhesive 8 is bonded to, for example, the bottom portion, the sidewall, or the bottom portion and the sidewall of the thin portion 30r of the object of the third lens array 30. The second spacer 50 has a spacer main body 51 and an opening 52 (light transmission portion). The spacer main body 51 is a lattice frame-shaped part, and the opening 52 has a rectangular shape. The opening 52 is formed as a through hole at a position corresponding to the lens portion 20a and the like. The lens portion 20a of the second lens array 20 and the lens portion 30a of the third lens array 30 are indirectly related to the axis AX direction and the direction perpendicular thereto by a rectangular frame (a part of the spacer body 51) around the opening 52. It will be supported.

In addition, as the 2nd spacer 50, the 1st spacer 40 WHEREIN: The surface treatment for reducing reflection in what was formed with the material of black or dark color, or was formed with the material which has a light transmittance. In addition, a film formed with a dark color layer can be used. When the second spacer 50 is formed of a light transmitting material, the adhesive 8 can be a black or dark material.

Each lens portion 10a of the first lens array 10 and the lens portion 20a of the second lens array 20 disposed to face the −Z side of the first lens array 10 sandwich the corresponding portion of the first spacer 40 therebetween. Aligned along the axis AX. Each lens portion 20a of the second lens array 20 and the lens portion 30a of the third lens array 30 disposed to face the −Z side of the second lens array 20 have an axis AX with a corresponding portion of the second spacer 50 interposed therebetween. Are aligned and arranged. As a result, the three lens portions 10a, 20a and 30a arranged on the axis AX constitute one synthetic lens 1a. The plurality of synthetic lenses 1a arranged two-dimensionally on the lattice points correspond to a single-eye lens of a field division method or a super-resolution method, that is, a single-eye optical system. Here, the visual field division method refers to a method of obtaining one image by connecting images of different visual fields formed by individual lenses and connecting the images of the respective visual fields by image processing. The super-resolution method refers to a method of obtaining one high-resolution image by image processing from images of the same field of view formed by individual lenses.

The IR cut filter 60 is formed of flat glass, and a dielectric multilayer film is formed on at least one of the surfaces 60p and 60q. The IR cut filter 60 prevents infrared rays that have passed through the lens arrays 10, 20, and 30 from entering the sensor array 81. The IR cut filter 60 is joined to the joint AS <b> 3 of the third lens array 30 in the same manner as the second spacer 50.

As shown in FIGS. 1A and 1B, the sensor array 81 of the imaging apparatus 1000 is connected to the compound-eye optical system 100 via the third spacer 70. The sensor array 81 has a main body portion 81a and a cover glass portion 81b. The main body portion 81 a is provided with a plurality of detection units 82 (sensor elements) corresponding to the individual composite lenses 1 a constituting the compound-eye optical system 100. The image processing unit 85 performs processing on the image signal detected by the sensor array 81. Each sensor element 82 generates image data corresponding to the image projected on the detection surface, and the image processing unit 85 creates a reconstructed image based on the image data output from the sensor element 82.

The third spacer 70 is a plate-like member formed of glass, ceramics, metal, resin, or the like having a lower linear expansion coefficient than the lens arrays 10, 20, and 30, and the first and second spacers 40, 50. Similar to the (connecting member), it has a shape corresponding to the joint AS3 of the third lens array 30, that is, a lattice frame-like contour shape. The third spacer 70 is bonded to the surface 60q of the IR cut filter 60 by the adhesive 8 on one main surface 70a side, and the cover glass portion of the sensor array 81 by the adhesive 8 on the other main surface 70b side. It is joined to 81b. That is, the third spacer 70 is a connection member that connects the compound eye optical system 100 and the sensor array 81. Further, the third spacer 70 and the IR cut filter 60 constitute a joining member that connects the lens array laminate 200 and the sensor array 81. The third spacer 70 has a spacer body 71 and an opening 72. The spacer main body 71 is a lattice frame-shaped part, and the opening 72 has a rectangular shape. The opening 72 is formed as a through hole at a position corresponding to the lens portion 30a and the like.

The third spacer 70 may be the same as the first spacer 40 or the second spacer 50 described above with respect to light shielding properties, light-absorbing coating, and the like.

The case 100a is formed of a light-blocking resin material and has a circular opening 100b facing the lens portion 10a of the first lens array 10. The compound eye optical system 100 in the case 100a is fixed at a proper position of the case 100a by an adhesive supplied to the inner wall of the case 100a, the periphery of the opening 100b, and the like.

Hereinafter, the thermal deformation simulation of the compound eye optical system 100 will be described with reference to FIGS. 5A and 5B. The simulation was performed using a model that simplified the structure of the lens array stack. FIG. 5A is a perspective view exaggeratingly showing a state of thermal deformation of a simplified model of the compound eye optical system 100 of the embodiment shown in FIG. 1A and the like, and FIG. 5B shows four resin layers for comparison. It is the perspective view which exaggerated and showed the mode of the thermal deformation of the structure (comparative example) connected by the surrounding frame. Specifically, in the case of FIG. 5A, four resin layers 91 are joined in an array unit by glass spacers 92, and in the case of FIG. 5B, the four resin layers 91 are externally attached by lattice-like glass spacers 192. It has a structure joined by a frame. The resin layer 91 is made of polycarbonate, the linear expansion coefficient is 65 ppm [1 / ° C.], and the linear expansion coefficient of the glass spacer 192 is 3.3 ppm [1 / ° C.]. Here, the linear expansion coefficient can be measured in accordance with procedures defined in JIS K7197 for plastic materials, JIS R1618 for ceramic materials, JIS Z2285 for metal materials, and JIS R3102 for glass materials. it can. The resin layer 91 was a square resin substrate having a thickness of 0.5 mm and a side of 10 mm, and the glass spacer 92 was a glass substrate having a thickness of 0.5 mm in which 16 1.5 mm square openings were formed. As can be seen from the figure, in the structure of the comparative example shown in FIG. 5B, it can be understood that as the lens array on the image side becomes larger, a large warp occurs, and in particular, a large distortion occurs in the upper and lower Z directions in the third layer. Has occurred. On the other hand, in the structure simulating the compound eye optical system 100 of the embodiment shown in FIG. 5A, the deformation is smaller than that of the comparative example as a whole, and a substantially uniform slight distortion occurs in the entire rectangular parallelepiped having a side of several centimeters. I know that. In the case of the structure simulating the compound eye optical system 100 of the embodiment shown in FIG. 5A, the position change is 3 μm or less, but in the case of the structure of the comparative example shown in FIG. 5A, the calculation is about 17 μm at maximum in the Z direction. A position change has occurred. In the case of the structure of the comparative example shown in FIG. 5B, the degree of warpage differs for each lens array because the lens arrays are not joined in units of lens elements, and the in-plane of the lens array stack 200 Therefore, the distance between the lens arrays varies, and the optical performance is extremely likely to deteriorate locally due to thermal effects. On the other hand, as shown in FIG. 5A, by joining with a connecting member for each lens element unit, even if the environmental temperature changes, local deterioration of optical characteristics can be prevented and optical performance can be maintained. In addition, since a plurality of lens arrays are joined via spacers and are restrained from each other, deformation due to a change in the environmental temperature of the lens array laminate 200 itself is suppressed. Can also be suppressed.

In the present embodiment, the spacers 40 and 50 are disposed in the thin portion 20r of the second lens array 20 and the thin portion 30r of the third lens array 30, respectively, and surrounding portions adjacent to the thin portions 20r and 30r. Spacers 40 and 50 are sandwiched between 20c and 30c or support portions 20b and 30b. Therefore, the spacers 40 and 50 can be easily positioned with respect to the lens arrays 20 and 30. In addition, when the environmental temperature rises and the lens arrays 20 and 30 expand, the lens arrays 20 and 30 look like holding the spacers 40 and 50, so that the warp of the lens array laminate 200 can be more effectively prevented. Can do.

As described above, in the imaging apparatus 1000 of the present embodiment, the first to third lens arrays 10, 20, and 30 are molded from a resin material by molding using a mold, and therefore the lens array 10 is affected by temperature. , 20 and 30 are relatively likely to warp, but the spacers 40 and 50 as connecting members between the adjacent lens portions 10a, 20a and 30a of the support portions 10b, 20b and 30b of the lens array 10, 20, and 30 are used. Therefore, the warp of the lens arrays 10, 20, and 30 can be reduced, and local deterioration of the imaging performance of the compound eye optical system 100 or the composite lens 1a can be suppressed. Therefore, it is possible to suppress deterioration of the optical performance of the compound eye optical system 100 that is a lens array laminate due to a change in environmental temperature, and to enable high-accuracy imaging. Moreover, the spacers 40 and 50 which are connection members each have a light absorptivity, and enter from the 1st lens part 10a of a certain synthetic lens 1a, and totally reflect in the lens arrays 10, 20, and 30. The stray light that propagates by the above and enters another adjacent synthetic lens 1a and can be recognized as a ghost is absorbed by the spacers 40 and 50, so that crosstalk and other deteriorations in imaging performance can be suppressed. That is, the spacers 40 and 50 that are connecting members have a function of suppressing optical interference or crosstalk between adjacent synthetic lenses 1a. For this reason, it is not necessary to separately provide a member for suppressing optical interference between the synthetic lenses 1a, the thickness of the entire lens array laminate 200 is not excessively increased, and good optical performance can be ensured. Furthermore, since the warp of the lens array laminate 200 itself is prevented, the IR cut filter 60 can be prevented from being damaged due to excessive stress.

[Second Embodiment]
The imaging device according to the second embodiment of the present invention will be described below. The imaging apparatus according to the second embodiment is a partial modification of the imaging apparatus according to the first embodiment, and items that are not particularly described are the same as those in the first embodiment.

As shown in FIGS. 6A and 6B, in the case of the imaging apparatus 1000 according to the second embodiment, the diaphragm 35 associated with the third lens array 30 is omitted, and the second spacer 50 (connection member) functions as the diaphragm 35. It has to be combined. For this reason, the second spacer 50 has a light shielding property, and the opening 52 has the same shape as the opening 35a of the diaphragm 35 shown in FIG. As in the first embodiment, the main body of the second spacer 50 is formed into a desired shape by etching or the like glass, ceramics, metal or the like having a smaller linear expansion coefficient than the first to third lens arrays 10, 20, and 30. It is formed by processing. The main body of the second spacer 50 can have a function as a diaphragm as long as the material itself is light-shielding and has a low reflectance. On the other hand, when the main body material of the second spacer 50 has translucency or reflectivity, a light-absorbing coating is formed on the surface, that is, at least one of the upper and lower main surfaces 50a and 50b, so that light-shielding properties and light-absorbing properties are achieved. Can be included. Such light-absorbing coating is performed by applying a black resist on the surface of the main body material such as glass. Further, the light-shielding property of the second spacer 50 can also be ensured by making the adhesive 8 used for joining light-absorbing and applying the adhesive 8 widely to the edge of the opening 52.

In the case of this embodiment, the third spacer 70 has a diaphragm function. For this reason, the third spacer 70 has a light shielding property, and narrows the light rays incident on the sensor element 82 through the opening 72. As in the first embodiment, the main body of the third spacer 70 is formed into a desired shape by etching or the like glass, ceramics, metal or the like having a smaller linear expansion coefficient than the first to third lens arrays 10, 20, and 30. It is formed by processing. The main body of the third spacer 70 can have a function as a diaphragm as long as the material itself is light-shielding and has a low reflectance. On the other hand, when the main body material of the third spacer 70 has translucency or reflectivity, a light-absorbing coating is formed on the surface, that is, at least one of the upper and lower main surfaces 70a, 70b, thereby having light shielding properties. it can. Such light-absorbing coating is performed by applying a black resist to the surface of the main body material such as glass as in the case of the second spacer 50. Further, the light-shielding property of the third spacer 70 can also be ensured by making the adhesive 8 used for joining light-absorbing and applying the adhesive 8 widely up to the edge of the opening 72.

In the present embodiment, the first spacer 40 suppresses generation of a ghost due to light propagating in the first lens array 10, and the second spacer 50 is adjacent by cutting unnecessary light in a certain synthetic lens 1a. It is prevented from overlapping the image of the synthetic lens 1a. That is, the spacers 40 and 50, which are connecting members, have a function of suppressing optical interference or crosstalk between adjacent synthetic lenses 1a, and the second spacer 50 has a light shielding property. Since it also serves as the diaphragm 35 of the first embodiment, the configuration can be simplified as compared with the first embodiment.

As shown in FIG. 7, in the case of the imaging apparatus 1000 of the modified example, the diaphragm 25 associated with the second lens array 20 is omitted, and the first spacer 40 (connection member) has the function of the diaphragm 25. ing. For this reason, the first spacer 40 has a light shielding property, and the opening 42 has the same shape as the opening 25a of the diaphragm 25 shown in FIG. The main body of the first spacer 40 is formed by processing glass, ceramics, metal, or the like having a smaller linear expansion coefficient than the first to third lens arrays 10, 20, 30 by etching or the like. The first spacer 40 can have a function as a diaphragm as long as the material itself has a light shielding property and a low reflectance. On the other hand, when the main body material of the first spacer 40 has translucency or reflectivity, a light-absorbing coating is formed on the surface, that is, at least one of the upper and lower main surfaces 40a and 40b, thereby having a light-shielding property. it can. Such light-absorbing coating is carried out by applying a black resist to the surface of the main body material such as glass as in the case of the second spacer 50. Further, the light-shielding property of the first spacer 40 can also be ensured by making the adhesive 8 used for joining light-absorbing and applying the adhesive 8 widely up to the edge of the opening 42. In this modification, the number of parts can be further reduced as compared with the first embodiment.

8A to 8C are diagrams for explaining the opening shape of the second spacer 50 and the like. In the case shown in FIG. 8A, the opening 52 of the second spacer 50 is rectangular or rectangular. In the case shown in FIG. 8B, the opening 52 of the second spacer 50 is a rounded rectangle or a rectangle. Furthermore, in the case shown in FIG. 8C, the opening 52 of the second spacer 50 is circular. Similarly to the case of the second spacer 50, the opening 72 of the third spacer 70 may be circular, rectangular with a corner, or rectangular. Similarly to the case of the second spacer 50, the opening 42 of the first spacer 40 may be circular, rectangular with a corner, or rectangular. In general, the circular opening can increase the bonding area by the spacers 40, 50, and 70, which is advantageous from the viewpoint of preventing deformation. In addition, the circular opening reduces the alignment burden related to rotation and makes it easy to improve positioning accuracy. By making a rectangular opening with a corner, the bonding area can be made wider than that of the rectangle. On the other hand, in view of an effective light beam used for imaging, the first spacer 40 close to the object side preferably has an opening having a circular shape or a shape similar thereto, and the second and third spacers close to the image side. 50 and 70 preferably have an opening having a rectangular shape or a shape similar thereto. That is, it is desirable that the openings 42, 52, 72 have a contour corresponding to the effective light flux cross section passing through the synthetic lens 1a. Surfaces that make the spacers 40, 50, and 70 light-shielding materials and reduce transmission and reflection on the spacers 40, 50, and 70 because the openings 42, 52, and 72 have an outline corresponding to the effective light flux cross section. If a light-shielding property is imparted to the spacers 40, 50, and 70 by processing, the spacers 40, 50, and 70 function as a diaphragm as they are. Therefore, it is not necessary to provide a separate diaphragm member, and good optical performance can be exhibited while keeping the structure of the lens array laminate 200 simple.

[Third Embodiment]
Hereinafter, an imaging device according to a third embodiment of the present invention will be described. The imaging apparatus according to the third embodiment is a partial modification of the imaging apparatus according to the first embodiment, and matters not specifically described are the same as those in the first embodiment.

As shown in FIG. 9A, a shallow groove 98 is formed around the opening 42 in the first spacer 40 (connection member). The presence of the groove 98 prevents the adhesive 8 from entering the groove 98 when the image-side main surface 10q of the first lens array 10 and the object-side main surface 40a of the first spacer 40 are bonded. As shown in FIG. 9B, the groove 98 remains as a gap 99 that becomes a ventilation path even after the first spacer 40 and the first lens array 10 are joined. A gap 99 formed between the first and second lens arrays 10 and 20 forms a ventilation path that communicates with a space where the first and second lens portions 10a and 20a face each other. By providing the groove 98 at a position corresponding to the gap 99, the ventilation path can be easily formed. The main surface 40a on the object side of the first spacer 40 has been described above, but the same shallow groove 98 is also formed on the main surface 40b on the image side of the first spacer 40 or the main surface 50a on the object side of the second spacer 50. Can be formed. Further, a similar shallow groove 98 can be formed on either the object-side main surface 70a or the image-side main surface 70b of the third spacer 70. When the air rises from 20 ° C. to 85 ° C., the volume of the air becomes 1.23 times. However, when the air is confined in the sealed space, the possibility of causing peeling of the adhesive due to air pressure fluctuation increases. In addition, when a sealed space is formed in the synthetic lens 1a, the possibility of excessive or insufficient adhesive or poor adhesion is increased in the manufacturing process. In the present embodiment, by providing a ventilation path, it is possible to prevent a sealed space from being formed between the optical surfaces in the synthetic lens 1a, and a resin lens accompanying expansion and contraction of the sealed space due to a change in environmental temperature. The deformation of the arrays 10, 20, and 30 can be suppressed. For this reason, regardless of the environmental temperature change, adhesion and fixing by the first and second spacers 40, 50, etc. can be ensured. That is, it is possible to prevent performance deterioration due to adhesion peeling or distortion of the lens portions 10a, 20a, and 30a having low rigidity compared to glass.

The shape of the groove 98 formed in the first spacer 40 is linear if it has a path connecting the pair of openings 42 or a path connecting the opening 42 and the outer frame side surface of the first spacer 40. It is not restricted to what extends. As long as the number of the grooves 98 is one or more around the opening 42 of the first spacer 40, the formation of the sealed space as long as the space formed by the grooves 98 connecting the plurality of openings 42 is open to the outside. Can be prevented.

The imaging device according to the embodiment has been described above, but the imaging device according to the present invention is not limited to the above. For example, in the above embodiment, the first to third lens arrays 10, 20, and 30 are obtained by molding using a mold from a thermoplastic resin material, but the first to third lens arrays 10, 20 and 30 may be formed by a mold using an energy curable resin material such as a photocurable resin material or a thermosetting resin material.

In the second embodiment, the light-absorbing coating is formed on the surfaces of the spacers 40, 50, and 70 as an example, but various surface treatments that reduce the transmission or reflection of light are possible.

In the above embodiment, the spacers 40, 50 as the connecting members have a function of adjusting the distance between the lens arrays 10, 20, 30, etc., but the spacers 40, 50 need not necessarily have the function of adjusting the distance. . For example, the lens arrays 10, 20, 30 themselves may be formed with a structure that serves as an abutting portion for adjusting the distance, or an uncured adhesive is applied to the lens array so as to face the other lens array, The distance can be adjusted by curing the adhesive while keeping the distance at a constant.

The arrangement of the lens portions 10a, 20a, and 30a constituting the lens arrays 10, 20, and 30 and the shape of the optical surfaces 11a, 11b, 21a, 21b, 31a, and 31b depend on the use or specification of the compound eye optical system 100 or the imaging apparatus 1000. It can be changed accordingly. For example, the lens portions 10a, 20a, and 30a are not limited to being arranged at 4 × 4 lattice points, but can be arranged at lattice points of 3 × 3, 5 × 5, and the like. In addition, the arrangement of the lens portions 10a, 20a, and 30a is not limited to a rectangular lattice, and can be various arrangements. Furthermore, the lens array constituting the compound-eye optical system 100 is not limited to three layers, and may be two layers (first and second lens arrays 10 and 20) or four or more layers.

In each of the above embodiments, the lens array, the spacer, and the case have a square outer shape. However, the shape is not limited to this, and may be a rectangle other than the square.

Claims (10)

A resin-made first lens array having a plurality of first lens portions and a first support portion for supporting the plurality of first lens portions from the periphery, a plurality of second lens portions, and the plurality of second lenses. A lens array laminate formed by laminating a resin-made second lens array having a second support portion for supporting the lens portion from the periphery in the optical axis direction via a connecting member;
A sensor array on which a plurality of images are formed by the lens array stack;
An image processing unit that creates a reconstructed image from a plurality of images obtained by the sensor array,
The first lens array and the second lens array face each other with the plurality of first lens portions and the plurality of second lens portions, and between the adjacent first lens portions of the first support portion, It is joined to the first surface, and is joined to the second surface of the connecting member between the adjacent second lens portions of the second support portion,
The coupling member is made of a material having a smaller linear expansion coefficient than the first and second lens arrays, and optical interference between a plurality of synthetic lenses configured by the first and second lens portions. An imaging device having a function of suppressing the above. The imaging apparatus according to claim 1, wherein the connecting member is formed of any one of glass, metal, and ceramics. The imaging device according to claim 1, wherein the connecting member has a light shielding property. The imaging device according to any one of claims 1 to 3, wherein the connecting member is subjected to a surface treatment that reduces transmission or reflection. The imaging device according to any one of claims 1 to 4, wherein the connecting member is bonded to the first and second lens arrays with an adhesive having a light shielding property. The imaging device according to any one of claims 1 to 5, wherein the connecting member is a plate-like member having a light transmission portion corresponding to the plurality of lens portions. The imaging apparatus according to claim 6, wherein the light transmission part has an outline corresponding to an effective light beam cross section. 2. A gap is provided between at least one of the first and second lens arrays and the connecting member so as to form a ventilation path communicating with a space where the plurality of first and second lens portions face each other. The imaging device according to any one of claims 1 to 7. The imaging device according to claim 8, wherein the connecting member has a groove at a position corresponding to the gap. A connection disposed between the second lens array and the sensor array, and fixed to the second support part and the sensor array between adjacent second lens parts of the second lens array by bonding. The imaging apparatus according to any one of claims 1 to 9, further comprising a member.

Images