JP2017125870A - Imaging module and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging module and an imaging device which can be made thin and can image a subject in a wider angle.SOLUTION: An imaging module 10 includes: an image sensor 14 in which a plurality of pixels for converting incident light into an electric signal are two-dimensionally arranged; and a first lens sheet 11 and a second lens sheet 12 disposed on an incident side of light of the image sensor 14. The first lens sheet 11 and the second lens sheet 12 have, on one surface side of the respective sheets, light-transmitting parts 111, 121 having a convex unit lens shape and light-absorbing parts 113, 123 alternately arranged with the light-transmitting parts 111, 121 and extending in a thickness direction of the lens sheet. The first lens sheet 11, the second lens sheet 12 and the image sensor 14 are curved in a direction where light is incident.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an imaging module and an imaging apparatus.

  In recent years, cameras used for crime prevention, surveillance, etc., like ordinary cameras, require correction of lens aberration, etc. in order to shoot high-quality images, so imaging consisting of multiple lenses A lens is used. However, since this imaging lens is composed of a plurality of lenses, the imaging lens occupies most of the thickness of the camera as a whole. For this reason, in such a camera for monitoring or the like, it is a big problem to achieve both high-quality image shooting and thinning.

  In addition, a camera used for such monitoring generally has a function of photographing a subject as a two-dimensional image, but may not be able to sufficiently capture the characteristics of the photographed subject. It is desired to photograph from a wide angle range. Therefore, in order to capture a captured subject image more clearly and over a wide range, for example, a special lens such as a fisheye lens may be used, or a stereo camera system using a plurality of cameras may be used. (For example, patent document 1). However, in this case, the configuration of the camera itself is increased, and it is very difficult to reduce the size and thickness of the camera.

On the other hand, a camera called a light field camera that can change a focal length and a depth of field after photographing has been developed and spread in recent years (see, for example, Patent Document 2). This light field camera uses a microlens array placed on an image sensor to divide incident light and shoot light in multiple directions, thereby performing predetermined image processing based on the incident direction and intensity of light after shooting. To change the focal length and depth of field of the image and photograph the subject in three dimensions.
In the light field camera, in order to prevent the light (image) from each lens of each microlens array arranged on the image sensor from overlapping on the light receiving surface, the above-described imaging lens and each lens are not connected. A partition sheet having a corresponding partition is required.
As described above, since the imaging lens is composed of a plurality of lenses, it is large and it is difficult to reduce the size and thickness of the light field camera. Further, when the partition sheet is disposed, there is a problem that it is difficult to align the partition wall with the microlens array.

JP 2011-151636 A Special table 2015-520992 gazette

  An object of the present invention is to provide an imaging module and an imaging apparatus that can be thinned and can photograph a subject at a wider angle.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
According to a first aspect of the present invention, there is provided an image pickup element portion (14) in which a plurality of pixels for converting incident light into an electric signal are two-dimensionally arranged, and a lens sheet (11) arranged on the light incident side of the image pickup element portion. 12), and the lens sheet (11, 12) is arranged along the sheet surface, and has a light transmitting part (111, 121) having a convex unit lens shape (112, 122) on one surface side. ) And light absorbing portions (113, 123) alternately arranged with the light transmitting portions and extending along the thickness direction of the lens sheet, and the lens sheet and the imaging device portion are incident with light. An imaging module (10) characterized by being curved in the direction.
According to a second aspect of the present invention, in the imaging module (10) of the first aspect, the lens sheets (11, 12) and the imaging element section (14) are curved so as to protrude toward the light incident side. The imaging module characterized by the above.
According to a third aspect of the present invention, in the imaging module (10) of the first aspect or the second aspect, the light transmission part (111) is arranged in a plurality of directions along a sheet surface, and the light absorption part (113) is an imaging module characterized in that it is provided between the light transmission parts adjacent to each other so as to surround each of the light transmission parts.
According to a fourth invention, in the imaging module (10) of the first invention or the second invention, the light transmitting portion (111, 121) is formed in a columnar shape, and the sheet surface of the lens sheet (11, 12) The light absorption part (113, 123) extends in the longitudinal direction of the light transmission part, and is an imaging module characterized in that the light absorption part (113, 123) extends in the longitudinal direction of the light transmission part.
According to a fifth aspect of the present invention, in the imaging module (10) of the fourth aspect, two lens sheets (11, 12) are provided, each laminated on the light incident side of the imaging element section (14). As seen from the optical axis direction, the arrangement direction of the light transmission parts (111) of one of the lens sheets (11) and the light transmission part (121) of the other lens sheet (12) are arranged. The imaging module is characterized in that it intersects with the arrangement direction of ().
According to a sixth invention, in the imaging module (10) of the fifth invention, when viewed from the optical axis direction, the arrangement direction of the light transmission portions (111) of one of the lens sheets (11) and the other lens The imaging module is characterized in that an intersection angle α at which the arrangement direction of the light transmission portions (121) of the sheet (12) intersects satisfies 80 ° ≦ α ≦ 100 °.
7th invention is an imaging device (1) provided with any imaging module (10) from 1st invention to 6th invention.

  According to the present invention, it is possible to provide an imaging module and an imaging apparatus that can be thinned and can photograph a subject at a wider angle.

It is a figure explaining camera 1 of an embodiment. It is a figure explaining imaging module 10 of an embodiment. It is a figure explaining the lens sheet unit 13 of embodiment. It is a figure explaining the 1st lens sheet 11 of an embodiment. It is a figure explaining the 2nd lens sheet 12 of an embodiment. It is a figure explaining an example of the manufacturing method of the 1st lens sheet 11 of an embodiment. It is a figure explaining the mode of image formation on the light-receiving surface of the image sensor 14 of the imaging module 10 of embodiment. FIG. 6 is a diagram illustrating the orientation of the lens shape surface 11a of the first lens sheet 11 and the lens shape surface 12a of the second lens sheet 12. It is a figure which shows an example of the other layer structure of the 1st lens sheet 11 and the 2nd lens sheet. It is a figure explaining another form of an imaging module. It is a figure explaining the detail of the lens sheet 11 used for the imaging module of another form. It is a figure explaining another form of the unit lens shape 112 provided in the lens sheet 11 used for the imaging module of another form. It is a figure which shows the deformation | transformation form of the lens sheet unit. FIG. 4 is a diagram illustrating a relationship between an arrangement direction of light transmitting portions 111 and 121 of the lens sheet unit 13 and an arrangement direction of pixels of the image sensor 14.

Embodiments of the present invention will be described below with reference to the drawings. In addition, each figure shown below including FIG. 1 is the figure shown typically, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.
Numerical values such as dimensions and material names of the respective members described in the present specification are examples of the embodiment, and the present invention is not limited thereto, and may be appropriately selected and used.
In this specification, terms that specify shape and geometric conditions, for example, terms such as parallel and orthogonal, are strictly meanings, have similar optical functions, and can be regarded as parallel and orthogonal It also includes a state having an error of.
In the present specification, the sheet surface refers to a surface which is a planar direction of the sheet when viewed as the entire sheet in each sheet-like member.

(Embodiment)
FIG. 1 is a diagram illustrating a camera 1 according to the present embodiment.
FIG. 2 is a diagram illustrating the imaging module 10 of the present embodiment.
In each of the following drawings including FIG. 1, an XYZ orthogonal coordinate system is provided as appropriate for easy understanding. In this coordinate system, when the photographer supports the imaging apparatus in a basic posture and takes an image with the optical axis O being horizontal, the horizontal direction (left-right direction) is the X direction and the vertical direction (up-down direction) is Y. Direction, the optical axis O direction is the Z direction, the direction toward the left side (right side when viewed from the subject side) is the + X direction, the direction toward the upper vertical direction is the + Y direction, and the direction toward the subject side The + Z direction is assumed.

The camera 1 is an imaging device that can image a subject.
As shown in FIG. 1, the camera 1 includes an imaging module 10 in a housing 30 having an opening 20. In addition, the camera 1 includes a control unit, a storage unit, a shutter unit, a shutter drive unit, and the like (not shown).
The opening 20 is an opening for taking light from the subject side into the imaging module 10 of the camera 1. A cover glass 21 is disposed in the opening 20 so as to cover the opening 20 from the viewpoint of preventing entry of foreign matter such as dust and dirt into the imaging module 10.

The imaging module 10 of this embodiment includes a lens sheet unit 13, an image sensor 14, and the like in order from the light incident side (subject side, + Z side) along the optical axis O (Z direction). The imaging module 10 captures an image based on the output signal from the control unit described above.
As shown in FIGS. 1 and 2, the lens sheet unit 13 and the image sensor 14 are formed in a spherical shape so that a rectangular flat plate member is curved so as to be convex toward the subject side. The geometric center (the vertex most protruding toward the subject) is orthogonal to the optical axis O.

FIG. 3 is a diagram illustrating the lens sheet unit 13 of the present embodiment. FIG. 3A is a perspective view of the lens sheet unit 13, and in FIG. 3B, the light transmission part 111 of the first lens sheet 11 and the light transmission of the second lens sheet 12 constituting the lens sheet unit 13. The arrangement direction of the sections 121 is shown.
FIG. 4 is a diagram illustrating the first lens sheet 11 of the present embodiment. 4A shows an enlarged part of a cross section parallel to the arrangement direction of the light transmission portions 111 of the first lens sheet 11 and the thickness direction of the first lens sheet 11, and FIG. A part of the cross section shown in FIG.
FIG. 5 is a diagram illustrating the second lens sheet 12 of the present embodiment. FIG. 5A shows an enlarged part of a cross section parallel to the arrangement direction of the light transmission parts 121 of the second lens sheet 12 and the thickness direction of the second lens sheet 12, and FIG. A part of the cross section shown in FIG.
Actually, the first lens sheet 11 and the second lens sheet 12 are curved as shown in FIGS. 1 and 2, etc., but in the enlarged views of FIGS. 4 and 5, the curved state is illustrated. Omitted.

The lens sheet unit 13 is located on the subject side (+ Z side) of the image sensor 14 in the optical axis O direction (Z direction). In the lens sheet unit 13, two lens sheets, that is, a first lens sheet 11 and a second lens sheet 12, are laminated in order from the subject side (+ Z side) along the optical axis O direction (Z direction).
In the lens sheet unit 13, the first lens sheet 11 and the second lens sheet 12 are integrally laminated and supported by a support member (not shown), and the left and right direction (X direction) and the vertical direction (Y direction) with respect to the image sensor 14. ), The position in the optical axis O direction (Z direction), and the like are determined.

Further, as shown in FIG. 3, the first lens sheet 11 and the second lens sheet 12 of the lens sheet unit 13 are curved so as to be convex toward the object side and are formed in a spherical shape. The target center (the vertex that protrudes closest to the subject) is orthogonal to the optical axis O. Thus, by curving the lens sheets 11 and 12, light from the subject side can be incident from a wider angle range and taken into the image sensor 14 side.
Further, the first lens sheet 11 and the second lens sheet 12 are respectively curved with the same curvature, and the curvature radius R0 is preferably in the range of 30 mm ≦ R0 ≦ 80 mm.
If the radius of curvature R0 is less than 30 mm, the curve becomes too large, making it difficult to produce a curved lens sheet, and the thickness direction (Z direction) of the lens sheet (lens sheet unit). This is not desirable because the size increases and the imaging module becomes thick.
On the other hand, when the radius of curvature R0 is larger than 80 mm, the curvature of each lens sheet is too close to a flat plate shape, which is not desirable because much light cannot be incident on the image sensor side.

The first lens sheet 11 is columnar and has a plurality of light transmission portions 111 arranged in one direction along the sheet surface, and a plurality of light transmission portions 111 arranged alternately in the arrangement direction of the light transmission portions 111. The light absorption part 113 is provided. In the first lens sheet 11 of the present embodiment, as shown in FIG. 3A, the light transmission portions 111 are arranged in the vertical direction (Y direction), and the longitudinal direction (ridge line direction) is the horizontal direction (X direction). ) In parallel.
The light transmission part 111 is a transparent part that transmits light, and has a convex unit lens shape 112 on the image sensor 14 side (−Z side). The surface on the image sensor 14 side (−Z side) of the first lens sheet 11 is a lens shape surface 11 a in which a plurality of unit lens shapes 112 are arranged. Further, the back surface 11b which is the subject side (+ Z side) surface of the first lens sheet 11 (the surface opposite to the lens-shaped surface 11a) is substantially flat.

The unit lens shape 112 of the first lens sheet 11 is convex to the image sensor 14 side (−Z side), and the arrangement direction (Y direction) of the light transmission portions 111 and the thickness direction (Z of the first lens sheet 11). The cross-sectional shape in a cross section parallel to (direction) is a partial shape of a circle (arc shape). The unit lens shape 112 has a cross-sectional shape extending along the longitudinal direction of the light transmitting portion 111.
On the back surface 11b side (subject side, + Z side) of the light transmission portion 111, land portions 114 that are continuous in a direction parallel to the sheet surface are formed, and each light transmission portion 111 is joined to the land portion 114. ing.
The land portion 114 is a transparent portion that transmits light, like the light transmitting portion 111. The land portion 114 is preferably as thin as possible. The land portion 114 has a thickness of 0 (that is, a form in which the land portion 114 does not exist), which prevents stray light and the like, and produces a high-quality image. Ideal from the point of view. Note that the land portion 114 of this embodiment is formed integrally with the light transmission portion 111.

The light transmission part 111 is formed of a resin having a light transmission property, and its refractive index N1 is about 1.38 to 1.60.
The light transmitting portion 111 of the present embodiment is formed by an ultraviolet molding method or the like using an ultraviolet curable resin such as urethane acrylate, polyester acrylate, or epoxy acrylate.
In addition, the light transmission part 111 may be formed of other ionizing radiation curable resins such as an electron beam curable resin. The light transmitting portion 111 may be formed by a hot melt extrusion molding method using a thermoplastic resin such as PET (polyethylene terephthalate) resin or the like, or may be formed by glass.
An antireflection layer (not shown) having an antireflection function is formed on the surface of the unit lens shape 112. This antireflection layer is formed by coating a material having an antireflection function (for example, magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), fluorine-based optical coating agent, etc.) with a predetermined film thickness. The

In the present embodiment, an antireflection layer (not shown) having an antireflection function may be provided on the surface of the back surface 11b of the first lens sheet 11. For example, the antireflection layer is coated with a material having the above-described antireflection function (for example, magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), fluorine-based optical coating agent, etc.) with a predetermined film thickness. Etc. are formed.
In the present embodiment, the back surface 11 b of the first lens sheet 11 is a light incident surface to the lens sheet unit 13. Therefore, by forming an antireflection layer on the back surface 11b, reflection on the back surface 11b serving as an interface between the first lens sheet 11 and air is suppressed, and the amount of incident light is increased.

The light absorbing portion 113 has a function of absorbing light, and in front of the surface (back surface) 11b opposite to the lens shape surface 11a on which the unit lens shape 112 is formed, along the thickness direction of the first lens sheet 11. It is a wall-shaped part extending to the end. In addition, the light absorbing portion 113 extends along the longitudinal direction of the light transmitting portion 111.
As shown in FIG. 4, the light absorbing portion 113 has a wedge-shaped or rectangular cross-sectional shape in a cross section parallel to the arrangement direction and the thickness direction of the first lens sheet 11. As used herein, the wedge shape refers to a shape in which one end is wide and gradually narrows toward the other, and includes a triangle shape, a trapezoidal shape, and the like.

  The light absorbing portion 113 of the present embodiment has a trapezoidal shape in which the cross-sectional shape in a cross section parallel to the arrangement direction and the thickness direction of the first lens sheet 11 is larger on the lens shape surface 11a side than on the back surface 11b side. It has become. Not only this but the light absorption part 113 is good also as cross-sectional shape in the cross section parallel to the arrangement direction and the thickness direction of the 1st lens sheet 11 as a triangular shape which makes the back surface 11b side a vertex.

The light absorption unit 113 has a function of absorbing stray light that travels in the light transmission unit 111 and travels toward the other adjacent light transmission unit 111.
The light absorbing portion 113 is made of a light absorbing material such as carbon black (hereinafter referred to as a light absorbing material), a resin containing the light absorbing material, or the like.
The light absorbing material used for the light absorbing portion 113 is preferably a particulate member having a function of absorbing light in the visible light region. Examples of such members include metal salts such as carbon black, graphite and black iron oxide, pigments and dyes, resin particles colored with pigments and dyes, and the like.

When resin particles colored with pigments or dyes are used as the light absorbing material, the resin particles may be acrylic resin, PC (polycarbonate) resin, PE (polyethylene) resin, PS (polystyrene) resin, MBS. Those formed of (methyl methacrylate / butadiene / styrene) resin, MS (methyl methacrylate / styrene) resin or the like are used.
As the light absorbing material, carbon black or the like and colored resin particles as described above may be used in combination.
Examples of the resin containing the light absorbing material include ultraviolet curable resins such as urethane acrylate and epoxy acrylate, and ionizing radiation curable resins such as electron beam curable resins.
The light absorption part 113 of this embodiment is formed of an acrylic resin containing carbon black.

  The refractive index N2 of the light absorbing portion 113 is about 1.45 to 1.60. Further, the refractive index N2 of the light absorbing portion 113 is preferably N2 ≧ N1 with respect to the refractive index N1 of the light transmitting portion 111. This is because light is totally reflected at the interface between the light absorption unit 113 and the light transmission unit 111 and prevents unnecessary light from reaching the image sensor 14.

The dimensions of each part of the first lens sheet 11 are as follows.
The arrangement pitch P of the light transmitting portions 111 (unit lens shape 112) is preferably about 20 to 230 μm.
The radius of curvature R of the unit lens shape 112 is preferably about 10 to 180 μm.
The lens opening width D1 of the unit lens shape 112 is a dimension (the boundary between the unit lens shape 112 and the side surface of the light transmission part 111) on the lens shape surface 11a side of the light transmission part 111 in the arrangement direction of the light transmission parts 111. The dimension between the point t1 and the point t2), and is preferably about 20 to 200 μm.

The lens height H1 of the unit lens shape 112 is determined from the boundary t1 (t2, t4) between the unit lens shape 112 and the side surface of the light transmission part 111 in the thickness direction (Z direction) of the first lens sheet 11. It is a dimension to the point t3 which becomes the most convex, and is preferably about 2 to 40 μm.
The total thickness T of the light transmission part 111 is a dimension from the light transmission part 111 and the back surface 11b to the point t3 in the thickness direction (Z direction) of the first lens sheet 11, and is approximately 30 to 480 μm.

The width D2 of the light absorbing portion 113 is such that the side surface of the light transmitting portion 111 and the boundary t1 of the unit lens shape 112 in the arrangement direction of the light transmitting portion 111, and the side surface t of the adjacent light transmitting portion 111 and the boundary t4 of the unit lens shape 112. The distance is preferably about 1 to 30 μm.
The height H2 of the light absorbing portion 113 is the dimension of the light absorbing portion 113 in the thickness direction (Z direction) of the first lens sheet 11, and is preferably about 20 to 470 μm.

  The angle θ formed by the interface between the light absorbing portion 113 and the light transmitting portion 111 and the normal direction of the sheet surface is preferably 0 ° ≦ θ ≦ 10 °. By making the angle θ within the above-mentioned range, it is possible to achieve an effect that it is easy to release from the mold when manufacturing by shaping the ultraviolet curable resin. In addition, when the lens sheets 11 and 12 are attached to the image sensor 14, in order to reduce the shadowed portions of the light absorbing portions 113 and 123 and to keep a large number of effective pixels of the image sensor 14, a wedge-shaped light absorbing portion 113, It is preferable to reduce the overall width D2 of 123, and when the height H2 of the light absorbing portions 113 and 123 is set high, it is better to reduce the difference between the widths of the upper and lower ends of the light absorbing portions as much as possible. Therefore, the above range is preferable.

The land thickness D3 is the thickness of the land portion 114, and is a dimension from the front end of the light absorbing portion 113 on the back surface 11b side to the back surface 11b of the first lens sheet 11 in the thickness direction of the first lens sheet 11. When it is set to ˜50 μm, stray light or light incident on the predetermined light transmitting portion 111 (unit lens shape 112) may be propagated toward the other adjacent light transmitting portion 111 (unit lens shape 112). It is preferable from the viewpoint of suppressing.
By forming the first lens sheet 11 within the above-mentioned size range, the focal length is about 24-300 μm (converted value in air).

The second lens sheet 12 is an optical sheet positioned on the image sensor 14 side (−Z side) of the first lens sheet 11. The second lens sheet 12 is bonded to the subject side (+ Z side) of the image sensor 14 by a bonding layer 15 described later.
The second lens sheet 12 is columnar and has a plurality of light transmission parts 121 arranged in one direction along the sheet surface, and a plurality of light transmission parts 121 arranged alternately in the arrangement direction of the light transmission parts 121. The light absorption part 123 is provided. In the second lens sheet 12 of the present embodiment, as shown in FIGS. 3A and 5, the light transmission portions 111 are arranged in the left-right direction (X direction), and the longitudinal direction (ridge line direction) is up and down. It is parallel to the direction (Y direction).
Further, as shown in FIG. 3B, in the second lens sheet 12, the arrangement direction R12 of the light transmission part 121 and the light absorption part 123 is the first lens sheet as viewed from the optical axis O direction (Z direction). 11 intersects with the arrangement direction R11 of the light transmitting portions 111 and the light absorbing portions 113 to form an intersecting angle α. In the present embodiment, the intersecting angle α = 90 °.

The light transmission part 121 is a transparent part that transmits light, and has a convex unit lens shape 122 on the subject side (+ Z side). The subject side (+ Z side) surface of the second lens sheet 12 is a lens shape surface 12a in which a plurality of unit lens shapes 122 are arranged. Further, the back surface 12b which is the surface on the image sensor 14 side (−Z side) of the second lens sheet 12 is substantially flat.
As shown in FIG. 5, the light transmitting portion 121 includes a lens shape portion 121 a, a land portion 121 b, and a main body portion 121 c that are stacked in this order from the lens shape surface 12 a side in the thickness direction. In the present embodiment, the lens shape portion 121a, the land portion 121b, and the main body portion 121c are integrally formed with each other.
The lens shape portion 121 a is a portion provided on the most lens shape surface 12 a side of the second lens sheet 12, and a unit lens shape 122 is formed.

The land portion 121b is a portion provided between the lens shape portion 121a and the main body portion 121c, and is a portion that joins the light transmitting portions 121 adjacent to each other in the arrangement direction. Specifically, the land portion 121b is provided between the valley portion t11 of the lens shape portion 121a adjacent in the arrangement direction and the surface on the lens shape surface 12a side of the light absorption portion 123 in the thickness direction (Z direction). It has been. As with the land portion 114 of the first lens sheet 11, the land portion 121b is preferably as thin as possible, and the land portion 121b has a thickness of 0 (that is, the land portion 121b exists). However, it is ideal from the viewpoint of preventing stray light and providing a high-quality image.
The main body part 121 c is a part provided on the most back surface 12 b side of the second lens sheet 12, and is adjacent to the light absorption part 123 in the arrangement direction of the light transmission parts 121.

The unit lens shape 122 of the second lens sheet 12 is convex on the subject side (+ Z side), and as shown in FIG. 5, the arrangement direction (X direction) of the light transmission parts 121 and the second lens sheet 12 A cross-sectional shape in a cross section parallel to the thickness direction (Z direction) is a partial shape of a circle (arc shape). The unit lens shape 122 has a cross-sectional shape extending along the longitudinal direction of the light transmitting portion 121.
Further, the unit lens shapes 122 (light transmission portions 121) are in contact with the adjacent unit lens shapes 122 in the arrangement direction.

The light transmission part 121 is formed of a light-transmitting resin, and the refractive index N1 is about 1.38 to 1.60, similar to the light transmission part 111 of the first lens sheet 11.
The light transmission part 121 of this embodiment is formed of the same material as the light transmission part 111 of the first lens sheet 11 described above.
An antireflection layer (not shown) having an antireflection function is formed on the surface of the unit lens shape 122. This antireflection layer is formed by coating a material having an antireflection function (for example, magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), fluorine-based optical coating agent, etc.) with a predetermined film thickness. The

The light absorbing portion 123 is a wall-shaped portion having an action of absorbing light. Unlike the light absorption part 113 with the above-mentioned 1st lens sheet 11, the light absorption part 123 of this embodiment is a unit lens shape from the back surface 12b of the lens sheet 12 along the thickness direction of the 2nd lens sheet 12. FIG. It extends to the front of the lens-shaped surface 12a on which 122 is formed. The light absorbing portion 123 is provided between the side surface 121d of the light transmitting portion 121 (main body portion 121c) and the side surface 121d of the adjacent light transmitting portion 121 (main body portion 121c). (Y direction).
As described above, the light absorption unit 113 of the first lens sheet 11 and the light absorption unit 123 of the second lens sheet 12 are respectively disposed on the image sensor 14 side of the imaging module 10 in the lens sheet. Therefore, in the lens sheet unit 13, since the land portion of each lens sheet is located on the side away from the image sensor 14, the influence of leakage light on the image sensor 14 side caused by each land portion is affected. Can be minimized.

As shown in FIG. 5, the light absorbing portion 123 has a wedge-shaped or rectangular cross-sectional shape in a cross section parallel to the arrangement direction and the thickness direction of the second lens sheet 12. As used herein, the wedge shape refers to a shape in which one end is wide and gradually narrows toward the other, and includes a triangle shape, a trapezoidal shape, and the like.
The light absorbing portion 123 of the present embodiment has a cross-sectional shape in a cross section parallel to the arrangement direction and the thickness direction of the second lens sheet 12, and the isosceles whose size on the lens shape surface 12 a side is smaller than the size on the back surface 12 b side. It has a trapezoidal shape. Not only this but the light absorption part 123 is good also as the triangle shape which makes the cross-sectional shape in the cross section parallel to the arrangement direction and the thickness direction of the 2nd lens sheet 12 the vertex on the lens-shaped surface 12a side.
The light absorption unit 123 has a function of absorbing stray light that travels in the light transmission unit 121 and travels toward the other adjacent light transmission unit 121. The light absorbing portion 123 is formed of the same material and refractive index N2 as the light absorbing portion 113 of the first lens sheet 11.

The dimensions of each part of the second lens sheet 12 are as follows.
The arrangement pitch P of the light transmission parts 121 (unit lens shape 122) is the same as the arrangement pitch P of the light transmission parts 111 of the first lens sheet 11, and is preferably about 20 to 230 μm.
The curvature radius R of the unit lens shape 122 is the same as the curvature radius R of the unit lens shape 112 of the first lens sheet 11 and is preferably about 10 to 180 μm.
The lens opening width D11 of the unit lens shape 122 is the dimension of the unit lens shape 122 in the arrangement direction of the light transmission parts 121 (the dimension between the points t11 and t12), and is preferably about 20 to 230 μm. In the present embodiment, since the unit lens shape 122 is in contact with the adjacent unit lens shape 122, the lens aperture width D11 and the array pitch P have the same dimensions.

The lens height H11 of the unit lens shape 122 is from the valley t11 between the unit lens shapes 122 adjacent to each other in the thickness direction (Z direction) of the second lens sheet 12 to the point t13 where the unit lens shape 122 is most convex. And preferably about 2 to 40 μm.
The total thickness T of the light transmission part 121 is a dimension from the back surface 12b of the light transmission part 121 to the point t13 in the thickness direction (Z direction) of the second lens sheet 12, and the light transmission part of the first lens sheet 11 It is the same as the total thickness T of 111, and is about 30 to 480 μm.

The width D12 of the light absorbing portion 123 is the width dimension of the light absorbing portion 123 on the back surface 12b of the second lens sheet 12, and is preferably about 1 to 30 μm.
The height H12 of the light absorbing portion 123 is the dimension of the light absorbing portion 123 in the thickness direction (Z direction) of the second lens sheet 12, and is preferably about 20 to 470 μm.

The angle θ formed by the interface between the light absorbing portion 123 and the light transmitting portion 121 and the normal direction of the sheet surface is the same as the angle θ of the first lens sheet 11 and is preferably 0 ° ≦ θ ≦ 10 °. .
The land thickness D13 is the thickness of the land portion 121b, and the valley portion t11 between the unit lens shapes 122 adjacent to each other from the surface on the lens shape surface 12a side of the light absorbing portion 123 in the thickness direction of the second lens sheet 12. It is a dimension to. This land thickness D13 becomes stray light because stray light or light incident on the predetermined light transmitting portion 121 (unit lens shape 122) travels to the other adjacent light transmitting portion 121 (unit lens shape 122) side. From the viewpoint of suppressing the occurrence of such a problem, the thickness is preferably about 1 to 50 μm.

FIG. 6 is a diagram illustrating an example of a method for manufacturing the first lens sheet 11 of the present embodiment.
An example of the manufacturing method of the 1st lens sheet 11 is as follows.
First, as shown in FIG. 6 (a), a sheet-like member (hereinafter referred to as a base material layer) 51 for a base material made of PET resin or the like is prepared, and as shown in FIG. A release layer 52 is formed by applying and curing a melamine resin, an acrylic resin, or the like.

Next, using a molding die having a concave shape that shapes the light transmitting portion 111 and having a convex shape so that the portion that becomes the light absorbing portion 113 is shaped like a groove, As shown in FIG. 6C, the light transmission part 111 is formed on the release layer 52 of the base material layer 51. The molding surface of the molding die is formed in a curved state in a direction perpendicular to the sheet surface of the lens sheet, and the curved light transmission portion 111 is formed by this molding die.
Next, as shown in FIG. 6 (d), a material for forming the light absorbing portion 113 (a liquid binder containing the light absorbing material) is wiped (squeezed) in the groove portion between the light transmitting portions 111. Fill and cure to form the light absorbing portion 113.
Thereafter, the base layer 51 is peeled together with the release layer 52 as shown in FIG. Then, an antireflection layer (not shown) is formed on the lens shape surface 11a (front surface) and the back surface 11b of the unit lens shape 112, and the first lens sheet 11 is formed as shown in FIG. 6 (f).

Moreover, the 2nd lens sheet 12 is manufactured as follows, for example.
A lower mold in which a hole shape corresponding to the main body part 121c of the light transmission part 121 is formed and an upper mold in which a hole shape corresponding to the lens shape part 121a in which the unit lens shape 122 is provided are prepared. Here, the upper mold is formed of a material such as polycarbonate, acrylic, or silicone resin, and the lower mold is formed of a metal material such as copper.
First, after filling the lower mold with an ultraviolet curable resin, pressing the upper mold, irradiating ultraviolet rays through the upper mold to cure the resin, and releasing the mold, the light absorbing portion 123 is formed. A light transmitting portion sheet provided with a groove portion is prepared.
Then, the material of the light absorbing portion 123 (liquid binder containing a light absorbing material) is wiped (squeezed) into the groove portion of the produced transparent portion sheet, and is cured, and the light absorbing portion 123 is cured. Form.

Finally, the second lens sheet 12 is manufactured by cutting into a predetermined size.
Here, the molds for molding the first lens sheet 11 and the second lens sheet 12 are each formed in a curved state so that the molding surface thereof corresponds to the curved shape of each lens sheet. Therefore, the manufactured first lens sheet 11 is curved so that the back surface 11b side is convex, and the manufactured second lens sheet 12 is curved so that the lens shape surface 12a side is convex. It is done.
In addition, the curved shape of each lens sheet is not limited to the case where it is formed at the time of molding as described above, and may be formed by other methods. For example, after a flat lens sheet is manufactured, a curved shape is formed by heating or the like, or a holding frame that holds each lens sheet is prepared so that the flat lens sheet is held in a curved state. May be.

The manufacturing method of the 1st lens sheet 11 and the 2nd lens sheet 12 is not restricted to said example, According to the material etc. to be used, it can select suitably.
For example, the 1st lens sheet 11 may use the general-purpose member by which the peeling layer was previously formed in the base material layer 51 and the peeling layer 52 in the base material layer. The base material layer 51 is not limited to the above materials, and may be formed using triacetyl cellulose (TAC), polyester, polycarbonate (PC), polyurethane resin, polyacrylic resin, or the like, or a release layer. The material 52 is not limited to the above material, and may be formed using a silicone material, a fluorine compound material, or the like.
Further, for example, the first lens sheet 11 corresponds to the base material layer 51 after the base material layer 51 does not have the release layer 52 and the light transmission parts 111 and 121 and the light absorption parts 113 and 123 are formed. You may form the 1st lens sheet 11 and the 2nd lens sheet 12 by shaving a part.

The second lens sheet 12 is manufactured by manufacturing a light transmitting part sheet having no groove part by an ultraviolet molding method using an ultraviolet curable resin, and then forming the groove part on the back surface 11b by laser processing, dicing process, or the like. The light absorbing portion 123 may be manufactured by wiping, filling, and curing the material constituting the light absorbing portion 123 in the groove portion.
The second lens sheet 12 is opposite to the surface provided with the groove portion of the sheet after a sheet having a groove portion provided on one surface thereof is formed with an ultraviolet curable resin by an ultraviolet molding method using a lower mold. You may make it produce the light transmissive part sheet | seat by forming the lens-shaped part 121a by the ultraviolet-ray molding method on the side surface using an upper mold | type.

  The light absorbing portions 113 and 123 are formed not only by the wiping method described above, but also by filling the material for forming the light absorbing portions 113 and 123 in the groove between the light transmitting portions 111 by vacuum filling or the like. Alternatively, it may be formed by a filling method using a capillary phenomenon.

The bonding layer 15 is a layer that integrally bonds the lens sheet unit 13 (second lens sheet 12) and the image sensor 14 together.
The bonding layer 15 is formed of a pressure-sensitive adhesive or an adhesive and has light transmittance. The refractive index N3 of the bonding layer 15 is preferably equal to the refractive index N1 of the light transmission part 121 of the second lens sheet 12.
The image sensor 14 generates heat during driving, and the surface temperature rises to about 40 ° C. Therefore, from the viewpoint of suppressing deformation such as warpage of the lens sheet unit 13 due to heat generated by the image sensor 14, the bonding layer 15 preferably has heat resistance.
As such a bonding layer 15, an adhesive such as an epoxy resin or a urethane resin, or an adhesive is suitable.
Note that the bonding layer 15 having a refractive index N3 smaller than the refractive index N1 of the light transmitting portion 121 can also be applied. Examples of such a bonding layer 15 include a silicone-based pressure-sensitive adhesive.

The light transmitted through the lens sheet unit 13 is condensed by the unit lens shapes 112 and 122 so that the light receiving surface of the image sensor 14 described later is focused. That is, the radius of curvature R and the refractive index N1 of the unit lens shapes 112 and 122 are set so that the light receiving surface of the image sensor 14 is in focus.
The first lens sheet 11 and the second lens sheet 12 are arranged in a state where the unit lens shapes 112 and 122 are in contact with each other at the apexes (point t3, point 13) or close to each other. Air is present in the gap portion between the first lens sheet 11 and the second lens sheet 12.

  The first lens sheet 11 and the second lens sheet 12 are arranged in the arrangement direction of the light transmission part 111 and the light transmission part 121 (unit lens shape 112 and unit lens shape 122) when viewed from the optical axis O direction (Z direction). Are arranged so as to form an intersection angle α = 90 °. Further, the first lens sheet 11 and the second lens sheet 12 have light absorbing portions 113 and 123 between the light transmitting portions 111 and 121. Therefore, the lens sheet unit 13 is optically equivalent to a state in which microlenses are arranged in a two-dimensional direction (X direction and Y direction) and a light shielding wall is formed between the microlenses.

The image sensor 14 is a solid-state imaging device that converts light received by the light receiving surface into an electrical signal and outputs the electrical signal. In the image sensor 14, a plurality of pixels are arranged in a two-dimensional direction, and the intensity of light incident on the pixels can be detected by each pixel.
A plurality of pixels constituting the image sensor 14 are arranged in a two-dimensional direction on the surface on the subject side which is a light receiving surface of the image sensor 14. In the present embodiment, it is assumed that a plurality of pixels of the image sensor 14 are arranged in the horizontal direction and the vertical direction (X direction and Y direction).
As such an image sensor 14, for example, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like is preferably used.
In the present embodiment, a CMOS is used as the image sensor 14.

Further, as shown in FIGS. 1 and 2, the image sensor 14 of the present embodiment is curved and formed in a spherical shape so as to be convex toward the subject side (+ Z side), and has a geometric center of each. (A vertex that protrudes most toward the subject) is orthogonal to the optical axis O. In this way, by bending the image sensor 14, the light transmitted through the lens sheets 11 and 12 can be incident and imaged from a wider angle range.
Here, the curved image sensor 14 can be manufactured using a known technique (for example, Japanese Patent No. 5720304, Japanese Patent No. 5724322, or the like).
The image sensor 14 is formed with the same radius of curvature R0 as the first lens sheet 11 and the second lens sheet 12 described above.

  The light traveling from the opening 20 into the imaging module 10 enters the lens sheet unit 13 and passes through the first lens sheet 11 and the second lens sheet 12. At this time, the light transmitted through the lens sheet unit 13 is collected in the Y direction (vertical direction) as the arrangement direction by the unit lens shape 112 of the first lens sheet 11, The unit lens shape 122 collects light in the X direction (left-right direction) that is the arrangement direction. Further, in the first lens sheet 11 and the second lens sheet 12, part of the light traveling in the direction forming a large angle with respect to the optical axis O direction in the light transmitting portions 111 and 121 is transmitted to the light absorbing portions 113 and 123. Incident and absorbed. The light transmitted through the lens sheet unit 13 is focused on the light receiving surface of the image sensor 14.

At this time, as described above, the first lens sheet 11 and the second lens sheet 12 are arranged so that the longitudinal directions of the unit lens shapes 112 and 122 are orthogonal to each other. Is close to a form in which a plurality of microlenses are arranged in the X and Y directions.
On the light receiving surface of the image sensor 14, images formed by the pseudo microlens are formed without overlapping each other.

In the present embodiment, a plurality of pixels of the image sensor 14 are arranged so as to correspond to each of the pseudo microlenses. At the time of photographing, the light divided by the corresponding pseudo microlens enters each pixel, and the intensity of the light is detected by each pixel. In addition, from the relationship between each pixel and which unit lens shape 112, 122 on the XY plane is transmitted (the position of the pseudo microlens on the XY plane), the incident direction of the light incident on the pixel is It can be detected.
Information on the intensity and direction of incident light detected by each pixel obtained by the imaging module 10 at the time of photographing is stored in the storage unit, and the focal length is obtained by performing various calculations and the like by the control unit. Or image data with the depth of field changed or the like (refocus processing performed).
Further, as described above, the lens sheets 11 and 12 and the image sensor 14 constituting the imaging module 10 are each curved toward the subject side (+ Z side), so that the imaging module 10 has a wider angle range. Light can be imaged.

FIG. 7 is a diagram for explaining a state of image formation on the light receiving surface of the image sensor 14 of the imaging module 10 of the present embodiment.
In general, in a light field camera, a plurality of pixels 141 (pixel group) located in a predetermined region correspond to one microlens of the microlens array. And it is important that the image by each microlens is projected in a corresponding area | region, as shown to Fig.7 (a), for example.
At this time, for example, as shown in FIG. 7B, when the images of the respective microlenses are projected onto the adjacent region, and the images overlap, light having different positions and angles on the subject surface enters the same pixel. A phenomenon called crosstalk occurs, and the incident direction and intensity of light cannot be decomposed. In order to solve this problem, in the conventional light field camera, the diaphragm of the imaging lens provided on the subject side of the microlens array is used, or the partition sheet having the partition corresponding to the unit lens of the microlens array is microscopically used. It was necessary to prepare separately on the image sensor side of the lens array.

  However, according to the present embodiment, the light absorbing portions 113 and 123 of each lens sheet are formed between the light transmitting portions 111 and 121 and extend in the thickness direction (Z direction) of each lens sheet. The light collected by the unit lens shapes 112 and 122 without using a lens, a partition sheet, or the like and without causing crosstalk as shown in FIG. It can enter into the pixel 141 (pixel group) of an area | region. Thereby, the pixel 141 can output the intensity | strength and incident direction information of incident light with high precision.

From the above, according to the present embodiment, an imaging lens composed of a plurality of optical lenses is unnecessary, and the thickness of the lens sheet unit 13 can be suppressed to about several tens to several hundreds of μm. 1 can be reduced in thickness and weight. Further, since an imaging lens is not necessary, the production cost of the imaging module 10 and the camera 1 can be reduced.
Further, according to the present embodiment, the lens sheets 11 and 12 constituting the imaging module 10 and the image sensor 14 are curved so as to be convex toward the subject side (+ Z side). It is possible to shoot by taking light in the angle range.

  According to the present embodiment, since the light absorbing portions 113 and 123 provided in each lens sheet are composed of a member that absorbs light, even if light enters the lens sheet unit, each light absorbing portion The light can be prevented from entering the adjacent light transmitting portions. Thereby, the light condensed by the unit lens shapes 112 and 122 can be appropriately incident on the pixel 141 (pixel group) in the corresponding region of the image sensor 14, and the information on the intensity and the incident direction of the incident light. Can be output with high accuracy.

  Moreover, according to this embodiment, since the light absorption parts 113 and 123 are integrally formed in each lens sheet 11 and 12 corresponding to the light transmission parts 111 and 121 (unit lens shape 112 and 122), High-precision alignment between the partition sheet and the microlens array becomes unnecessary. Thereby, the fall of the yield by the alignment accuracy shift | offset | difference with a microlens array and a partition sheet | seat can be suppressed. Further, since alignment is not necessary, handling becomes easy, manufacture can be performed easily, and production cost can be reduced.

  Further, according to the present embodiment, it is easy to increase the unit lens shapes 112 and 122 arranged in the X direction and the Y direction by reducing the lens opening width D1 of the light transmitting portions 111 and 121, and the light. Since the absorption portions 113 and 123 are integrally formed, the pseudo microlens by the lens sheet unit 13 can be further refined, and the spatial resolution of the image can be improved.

The imaging module 10 and the camera 1 of the present embodiment can also form a captured image with pan focus, can form captured images with various focal lengths and depths of field, and can capture a subject image in three dimensions. Is possible. Therefore, it is possible to improve the accuracy of the authentication function such as a photographed person's face.
Furthermore, the conventional light field camera requires an imaging lens, a partition sheet for dividing light separate from the microlens array, and the like. However, according to the present embodiment, none of them is necessary, and therefore, a light field camera can be reduced in thickness and weight, production cost can be reduced, and the like.

(Another form of the lens sheet unit 13)
Hereinafter, another form of the lens sheet unit 13 will be described.
<Direction of Lens Shape Surfaces 11a and 12a of Each Lens Sheet>
FIG. 8 is a diagram illustrating the orientation of the lens-shaped surface 11 a of the first lens sheet 11 and the lens-shaped surface 12 a of the second lens sheet 12. In each drawing of FIG. 8, for easy understanding, only the first lens sheet 11 and the second lens sheet 12 constituting the lens sheet unit 13 are shown, and the bonding layer 15 and the like are omitted. . Moreover, in each figure of FIG. 8, although the 1st lens sheet | seat 11 and the 2nd lens sheet | seat 12 have shown the form spaced apart in the Z direction, actually, it has contact | connected or adjoined. Furthermore, in each figure of FIG. 8, illustration of the curved state of each lens sheet 11 and 12 is abbreviate | omitted.
As shown in each drawing of FIG. 8, the first lens sheet 11 and the second lens sheet 12 of the lens sheet unit 13 have lens-shaped surfaces 11a and 12a on the subject side (+ Z side) or on the image sensor 14 side. Whether it is (−Z side) can be appropriately selected.

As shown in FIG. 8A, the first lens sheet 11 and the second lens sheet 12 constituting the lens sheet unit 13 have lens shape surfaces 11a and 12a both on the subject side (+ Z side). It may be arranged.
Further, as shown in FIG. 8B, the first lens sheet 11 and the second lens sheet 12 constituting the lens sheet unit 13 have both lens-shaped surfaces 11a and 12a on the image sensor 14 side (-Z side). ) May be arranged.
Further, as shown in FIG. 8C, the first lens sheet 11 is arranged so that its lens-shaped surface 11a is on the subject side (+ Z side), and the second lens sheet 12 is its lens-shaped surface 12a. May be arranged on the image sensor side (−Z side).

In these cases, from the viewpoint of suppressing stray light and crosstalk caused by the land portion of each lens sheet, it is desirable that the light absorbing portion provided in each lens sheet is disposed on the image sensor side.
Specifically, in the case shown in FIG. 8A, the light absorbing portions 113 and 123 extend from the back surfaces 11b and 12b of the lens sheets 11 and 12 to the front of the lens-shaped surfaces 11a and 12a. It is desirable to be formed. 8B, the light absorbing portions 113 and 123 are formed so as to extend from the lens-shaped surfaces 11a and 12a side of the lens sheets 11 and 12 to the front of the back surfaces 11b and 12b. Is desirable. Further, in the case shown in FIG. 8C, the light absorbing portion 113 is formed to extend from the back surface 11b side of the first lens sheet 11 to the front of the lens-shaped surface 11a, and the light absorbing portion 123 is The two-lens sheet 12 is preferably formed so as to extend from the lens-shaped surface 12a side to the front of the back surface 12b.

  When the lens-shaped surface 12a of the second lens sheet 12 is located on the image sensor 14 side (−Z side) as shown in FIGS. 8B and 8C, the bonding layer 15 has a refractive index. N3 is preferably smaller than the refractive index N1 of the light transmission part 121 of the second lens sheet 12. As such a bonding layer 15, a silicone-based pressure-sensitive adhesive or the like is suitable.

  As shown in FIG. 8C, the surface of the first lens sheet 11 on the second lens sheet 12 side (−Z side) is the back surface 11b on which the unit lens shape 112 is not formed, and the second lens. When the surface of the sheet 12 on the first lens sheet 11 side is also the back surface 12b, a spacer (not shown) is provided between the first lens sheet 11 and the second lens sheet 12 from the viewpoint of suppressing the generation of stray light due to optical contact. May be arranged. At this time, from the viewpoint of enhancing the effect of suppressing the generation of stray light due to optical contact, the back surfaces 11b and 12b of both lens sheets may be mat surfaces on which fine irregularities are formed.

8C, a bonding layer (not shown) is provided between the first lens sheet 11 and the second lens sheet 12, so that the first lens sheet 11 and the second lens sheet 12 May be joined together. In the case of this embodiment, the refractive index of the bonding layer that bonds the first lens sheet 11 and the second lens sheet 12 is the reflection of light at the interface between the bonding layer and the back surfaces 11b, 12b of the lens sheets 11, 12. From the viewpoint of preventing the above, it is preferable that the refractive index of the light transmitting portions 111 and 121 is the same.
Even when the lens sheet unit 13 having such a configuration is used, it is possible to capture an image with good image quality.

<About the arrangement direction of the light transmitting portions 111 and 121 of each lens sheet>
In the lens sheet unit 13, the arrangement direction R11 of the light transmission portions 111 of the first lens sheet 11 is the left-right direction (X direction), and the arrangement direction R12 of the light transmission portions 121 of the second lens sheet 12 is the vertical direction (Y direction). It is good.
Further, as shown in FIG. 3B, the arrangement direction R11 of the light transmission portions 111 (unit lens shape 112) of the first lens sheet 11 and the light transmission portion 121 (unit lens shape 122) of the second lens sheet 12 are used. If the crossing angle α formed by the arrangement direction R12 is within the range of 90 ° ± 10 °, that is, within the range of 80 ° ≦ α ≦ 100 °, the optical function desired as the lens sheet unit 13 is maintained. The Therefore, the crossing angle α is not limited to 90 °, and may be within a range of 80 ° ≦ α ≦ 100 °.

  Therefore, when the imaging module 10 is assembled using the first lens sheet 11 and the second lens sheet 12 as the lens sheet unit 13, the arrangement direction R11 of the light transmission portion 111 of the first lens sheet 11 and the light transmission of the second lens sheet 12. The crossing angle α formed by the arrangement direction R12 of the portion 121 may not be strictly set to 90 °, and the assembling work of the lens sheet unit 13 and the imaging module 10 is facilitated, the working efficiency is improved, and the yield is improved. be able to.

<Regarding the layer structure of each lens sheet>
FIG. 9 is a diagram illustrating an example of another layer configuration of the first lens sheet 11 and the second lens sheet 12. FIG. 9A is a diagram illustrating another layer configuration of the first lens sheet 11 and corresponds to the above-described FIG. 4A. FIG. 9B is a diagram illustrating another layer configuration of the second lens sheet 12, and corresponds to the above-described FIG. 5A. In addition, in each figure of FIG. 9, illustration of the curved state of each lens sheet is abbreviate | omitted.

As shown to Fig.9 (a), the 1st lens sheet 11 is good also as a form by which the base material layer 51 was laminated | stacked integrally on the back surface 12b side. Similarly, as shown in FIG. 9B, the second lens sheet 12 may have a configuration in which the base material layer 51 is integrally laminated on the back surface 12 b side of the light transmission part 121.
From the viewpoint of suppressing crosstalk and the like, the first lens sheet 11 and the second lens sheet 12 are parallel to and continuous with the sheet surface such as a land portion (the light absorbing portions 113 and 123 are not formed). It is preferable that the thickness of the portion is smaller. Therefore, when the base material layer 51 is thin enough to sufficiently suppress crosstalk or the like, it may be used as a lens sheet with the base material layer 51 laminated as described above. By having such a base material layer 51, the first lens sheet 11 and the second lens sheet 12 can be handled easily.

(Another form of the imaging module 10)
FIG. 10 is a diagram illustrating another form of the imaging module 10. FIG. 10A is a front view of the imaging module as viewed from the light incident side (+ Z side), and FIGS. 10B and 10C are cross-sectional views of a portion b of FIG. It is c section sectional drawing.
FIG. 11 is a diagram for explaining the details of the lens sheet 11 used in the imaging module 10 of another form. In addition, each figure of FIG. 11 is a figure corresponding to each figure of FIG. In each drawing of FIG. 11, the curved state of the lens sheet 11 is not shown.

In the above-described embodiment, the imaging module 10 has been described as an example including two lens sheets (the first lens sheet 11 and the second lens sheet 12), but is not limited thereto. The imaging module 10 may include a single lens sheet 11 as shown in FIGS. 10B and 10C.
In this case, the lens sheet 11 used in the imaging module 10 includes, for example, a plurality of substantially hemispherical unit lens shapes 112 arranged in the left-right direction and the vertical direction along the sheet surface, as shown in FIGS. Is done. As shown in FIG. 10A, the unit lens shape 112 is formed in a circular shape when viewed from the normal direction (Z direction) of the sheet surface of the lens sheet 11. Here, the substantially hemispherical shape means not only a hemisphere but also a shape including a sphere and a partial shape of a spheroid.

In this case, like the first lens sheet 11 and the second lens sheet 12 of the above-described embodiment, the lens sheet 11 is curved and formed in a spherical shape so as to be convex toward the subject as shown in FIG. The geometric center (the vertex that protrudes most toward the subject) is orthogonal to the optical axis O. In addition, in FIG. 11, although the lens sheet 11 has shown the cross-sectional shape in a YZ cross section, the cross-sectional shape in a XZ cross section is formed in the same shape.
Even with such a configuration, the imaging module 10 and the camera can achieve the same effects as those of the above-described embodiment. In addition, since the imaging module 10 can be configured by a single lens sheet 11, the imaging module and camera can be further reduced in thickness and weight.

The imaging module 10 does not include the bonding layer 15 that bonds the lens sheet unit 13 and the image sensor 14, and the second lens sheet 12 is disposed in contact with the light receiving surface of the image sensor 14. The first lens sheet 11, the second lens sheet 12, and the image sensor 14 may be supported by a support member (not shown) and fixed at a predetermined position.
At this time, as shown in FIGS. 2, 3 and 8A, the surface on the image sensor 14 side (−Z side) of the second lens sheet 12 is the back surface on which the unit lens shape 122 is not formed. 12b, the back surface 12b is formed with a fine concavo-convex shape from the viewpoint of preventing the light receiving surface of the image sensor 14 from being damaged or preventing optical adhesion between the image sensor 14 and the second lens sheet 12. A surface is preferred.
Further, when the bonding layer 15 is not provided, a spacer is disposed between the second lens sheet 12 and the image sensor 14, for example, optical contact between the image sensor 14 and the second lens sheet 12 and light reception of the image sensor 14. The surface may be prevented from being scratched.

(Another form of the unit lens shape 112)
In the description of the imaging module of another form shown in FIG. 10 and FIG. 11 described above, the unit lens shape 112 provided on the lens sheet 11 is an example of being formed in a substantially hemispherical shape, but is not limited thereto. Not.
FIG. 12 is a diagram showing another form of the unit lens shape 112 of the lens sheet 11. FIG. 12A is a front view of the lens sheet 11 viewed from the subject side in the thickness direction. 12 (b) and 12 (c) are a cross-sectional view of a b portion and a cross-sectional view of a c portion in FIG. 12 (a), respectively.
As shown in FIG. 12A, the unit lens shape 112 (light transmitting portion 111) is formed in a rectangular shape (square shape) when viewed from the normal direction (Z direction) of the sheet surface of the lens sheet 11. You may make it do. In this case, the unit lens shape 112 is formed in a substantially quadrangular pyramid shape that swells on the subject side (+ Z side). Specifically, as shown in FIGS. 12B and 12C, the unit lens shape 112 has a form in which corners (tops and ridge lines) of a quadrangular pyramid are chamfered to form a curved surface. Become.

Even in such a form, the same effect as the unit lens shape shown in FIG. In addition, by making the shape viewed from the normal direction of the sheet surface rectangular, it is possible to increase the incident area of light on the lens sheet 11 as compared to the form shown in FIGS. Light utilization efficiency can be improved.
The unit lens shape 112 (light transmission portion 111) is formed in a substantially polygonal pyramid shape having a polygonal shape when viewed from the normal direction (Z direction) of the sheet surface of the lens sheet 11, and the substantially polygonal cone shape. May swell toward the subject side (+ Z side) of the sheet surface, and the corners (tops and ridges) may be chamfered.

(Deformation)
Without being limited to the embodiments described above, various modifications and changes are possible, and these are also within the scope of the present invention.
(1) In the above-described embodiment, the lens sheets 11 and 12 and the image sensor 14 are each curved on the subject side (+ Z side) and formed into a spherical shape. However, the present invention is not limited to this. . For example, the lens sheets 11 and 12 and the image sensor 14 may be formed in a curved shape (spheroid etc.) other than a sphere.
The lens sheets 11 and 12 and the image sensor 14 may be curved to the opposite side (−Z side) to the subject side.

(2) In the above-mentioned embodiment, although the example using the 1st lens sheet and the 2nd lens sheet from which the form of a light absorption part differs was shown, it is not limited to this, For example, it is the same as a 1st lens sheet A lens sheet of the form may be applied as the second lens sheet, or a lens sheet of the same form as the second lens sheet may be applied as the first lens sheet. This is particularly applicable when the land portion of each lens sheet is sufficiently thin and stray light and crosstalk are low.

(3) In the above-described embodiment, the imaging module 10 and the camera 1 may be provided with an infrared shielding layer that shields infrared rays in the lens sheet unit 13. Thereby, infrared rays that generate noise in the image (particularly, near infrared rays having a wavelength range of 700 to 1100 μm) can be shielded, and a good image can be taken.
In this case, in order to prevent the infrared light incident on the imaging module 10 from being shielded during night photography, the camera 1 needs to be provided with a retracting mechanism for retracting the infrared shielding layer from the optical axis O. There is.
In addition, the infrared shielding layer is disposed on the back surface 11b side of the first lens sheet 11, for example. However, the infrared shielding layer is not limited to this, and is in the lens sheet unit 13 and closer to the subject side than the image sensor 14. If there is, the position is not particularly limited.

Furthermore, when shielding by absorbing infrared rays, the infrared shielding layer is formed, for example, by coating an acrylic resin containing a material having infrared absorption characteristics. Examples of materials having infrared absorption characteristics include organic dye compounds (for example, cyanine compounds, phthalocyanine compounds, naphthoquinone compounds, diimmonium compounds, azo compounds), organic metal complex salts (for example, dithiol metal complexes, mercaptonaphthol metal complexes), inorganic materials ( Examples thereof include tin-doped indium oxide (ITO) and antimony-doped tin oxide (ATO)).
In addition, when the infrared shielding layer is shielded by reflecting infrared rays, for example, sputtering films such as zinc oxide, titanium oxide, ITO, ATO, vapor deposition films, etc. (multi-layer dielectric film of high refractive index layer and low refractive index layer) Etc.).

(4) The unit lens shapes 112 and 122 shown in FIG. 3 and FIG. 4 are such that, for example, the cross-sectional shape in the arrangement direction of the light transmitting portions 111 and 121 and the thickness direction (Z direction) of each lens sheet is the sheet surface. A part of an ellipse whose major axis is orthogonal, a polygonal shape, or the like may be used, or the top may be a curved line such as an arc, and the unit lens shape may have a straight line on the valley side.

(5) The lens sheet unit 13 is configured such that the light transmitting portions 111 and 121 and the light absorbing portions 113 and 123 having the unit lens shapes 112 and 122 are formed on both surfaces of a single sheet-like base material layer. Also good.
FIG. 13 is a view showing a modified form of the lens sheet unit 13.
As shown in FIG. 13, the modified lens sheet unit 13 includes light transmitting portions 111 and 121 and light absorbing portions 113 having unit lens shapes 112 and 122 on both surfaces of a single sheet-like base material layer 131. 123 is formed. This is equivalent to a shape in which the first lens sheet 11 and the second lens sheet 12 are integrally formed on both surfaces of the base material layer 131.
The base material layer 131 is a resin sheet-like member and has light transmittance. As such a base material layer 131, the sheet-like member made from PET resin containing an infrared absorber etc. is mentioned.
In addition, the thickness of the base material layer 131 is as thin as possible from the viewpoint of suppressing stray light, reducing crosstalk, and improving the intensity of light incident on each pixel and the accuracy of the incident direction. preferable.

(6) The lens sheet unit 13 may have a configuration in which three or more lens sheets are arranged along the optical axis O direction (Z direction).
At this time, for example, a third lens sheet (hereinafter referred to as a third lens sheet) is a lens sheet having the same shape as the first lens sheet 11 and the second lens sheet 12, and the arrangement direction of the light transmitting portions thereof However, it is preferable that 45 ° ± 10 ° is formed with respect to the arrangement direction of the light transmitting portions 111 and 121 of the first lens sheet 11 and the second lens sheet 12.
The lens shape surface of the third lens sheet may be on the subject side (+ Z side) or on the image sensor 14 side (−Z side).

Furthermore, when the fourth lens sheet (fourth lens sheet), which is a lens sheet having the same shape as the first lens sheet 11 and the second lens sheet 12, is arranged, the arrangement direction of the light transmitting portions is 45 ° ± 10 ° with respect to the arrangement direction of the light transmission portions 111 and 121 of the first lens sheet 11 and the second lens sheet 12, and 90 ° ± with respect to the arrangement direction of the light transmission portions of the third lens sheet. It is preferable that the angle is 10 °.
The lens shape surface of the fourth lens sheet may be on the subject side (+ Z side) or on the image sensor 14 side (−Z side).

(7) FIG. 14 is a diagram showing the relationship between the arrangement direction of the light transmission parts 111 and 121 of the lens sheet unit 13 and the arrangement direction of the pixels of the image sensor 14.
In the above-described embodiment, as shown in FIG. 14A, the pixels of the image sensor 14 are arranged in two directions G1 and G2 (Y direction and X direction) orthogonal to the optical axis O direction (Z direction). The arrangement direction R11 of the light transmission part 111 of the first lens sheet 11 is parallel to one direction G1 (Y direction) of the pixel arrangement direction, and the arrangement direction R12 of the light transmission part 121 of the second lens sheet 12 is An example in which the pixel is parallel to another direction G2 (X direction) of the pixel arrangement direction is shown.
At this time, when viewed from the optical axis O direction (Z direction), an angle β between the arrangement direction R11 of the light transmission portions 111 of the first lens sheet 11 and one direction G1 of the arrangement direction of the pixels, the second lens sheet 12 An angle γ formed by the arrangement direction R12 of the light transmission portion 121 and another direction G2 in the arrangement direction of the pixels is 0 °.

However, not limited to this, as shown in FIG. 14B, for example, when viewed from the optical axis O direction (Z direction), the angle β and the angle γ are within the range of 0 ° to 10 °. Since the optical function is maintained, it may be appropriately selected and set within this range. By adopting such a configuration, it becomes easy to align the image sensor 14 and the lens sheet unit 13 (the first lens sheet 11 and the second lens sheet 12), thereby simplifying the manufacturing work, shortening the work time, and yield. The improvement etc. can be aimed at.
13B shows an example in which the pixel arrangement directions G1 and G2 are parallel to the Y direction and the X direction. However, the present invention is not limited to this, and the arrangement directions R11, R11 of the light transmission portions 111, 121 are not limited thereto. R12 may be parallel to the Y direction and the X direction and form angles β and γ with the pixel arrangement directions G1 and G2, respectively. Alternatively, the pixel arrangement directions G1 and G2 and the arrangement direction of the light transmitting portions 111 and 121 may be used. R11 and R12 may form angles β and γ, and neither of them may be parallel to the Y direction and the X direction.

(8) The interface between the light transmitting portions 111 and 121 and the light absorbing portions 113 and 123 may be a folded surface formed of a plurality of planes, or a combination of a plurality of planes and curved surfaces. It is good.

(9) In the embodiment, the arrangement pitch P of the unit lens shapes 112 and 122, the radius of curvature R, the refractive index N1 of the light transmission portions 111 and 121, and the like are the same in the first lens sheet 11 and the second lens sheet 12. However, the present invention is not limited to this, and the first lens sheet 11 and the second lens sheet 12 may be different.
In addition, although the curvature radii R0 of the lens sheets 11 and 12 and the image sensor 14 are respectively equivalent, the curvature radii R0 may be different from each other.

(10) The first lens sheet 11 and the second lens sheet 12 are, for example, a region other than an effective portion of the sheet (a region through which light is transmitted), or a region having a small optical influence (for example, corner portions at four corners). For example, a bonding layer made of an adhesive, an adhesive, or the like may be formed and formed integrally. In addition, a region or the like that protrudes outward may be provided on the periphery of the first lens sheet 11 and the second lens sheet 12, and a bonding layer may be provided in the region.

(11) The size of the light receiving surface of the image sensor 14 may be appropriately adopted according to the size of a mobile terminal or camera in which the imaging module 10 is used, the desired image quality, camera performance, or the like. The size of the light receiving surface of the image sensor 14 is, for example, a camera with a horizontal (vertical) size of 4.8 × 3.6 mm or 4.4 × 3.3 mm when used in a mobile terminal such as a smartphone. In the case of being mainly used for compact digital cameras, etc., there are 6.2 × 4.7 mm, 7.5 × 5.6 mm, and the like.
Further, for example, by using the image sensor 14 having a large light receiving surface such as 23.6 × 15.8 mm, 36 × 24 mm, 43.8 × 32.8 mm, etc., noise can be reduced, the focal length to be acquired, and the subject image. The accuracy of information such as depth of field and the amount of information may be improved to further improve image quality and camera performance.

  In addition, although this embodiment and modification can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited by the above-described embodiments and the like.

DESCRIPTION OF SYMBOLS 1 Camera 10 Imaging module 11 1st lens sheet 111 Light transmission part 112 Unit lens shape 113 Light absorption part 12 2nd lens sheet 121 Light transmission part 122 Unit lens shape 123 Light absorption part 13 Lens sheet unit 14 Image sensor 20 Opening part 30 Enclosure

Claims (7)

An image sensor unit in which a plurality of pixels that convert incident light into an electrical signal are two-dimensionally arranged;
A lens sheet disposed on the light incident side with respect to the imaging element unit,
The lens sheet is arranged along the sheet surface, and is arranged alternately with the light transmitting part having a convex unit lens shape on one surface side and the light transmitting part, along the thickness direction of the lens sheet. An extending light absorbing portion,
The lens sheet and the imaging device section are curved in the direction of incidence of light;
An imaging module characterized by the above. The imaging module according to claim 1,
The lens sheet and the imaging element portion are curved to be convex toward the light incident side;
An imaging module characterized by the above. The imaging module according to claim 1 or 2,
The light transmission parts are arranged in a plurality of directions along the sheet surface,
The light absorbing portion is provided between the light transmitting portions adjacent to each other so as to surround each light transmitting portion;
An imaging module characterized by the above. The imaging module according to claim 1 or 2,
The light transmission part is formed in a columnar shape and arranged in one direction along the sheet surface of the lens sheet,
The light absorbing portion extends in a longitudinal direction of the light transmitting portion;
An imaging module characterized by the above. The imaging module according to claim 4,
Two lens sheets are provided, and each of the lens sheets is disposed so as to be laminated on the light incident side of the imaging element unit,
When viewed from the optical axis direction, the arrangement direction of the light transmission portions of one lens sheet and the arrangement direction of the light transmission portions of the other lens sheet intersect,
An imaging module characterized by the above. The imaging module according to claim 5, wherein
When viewed from the optical axis direction, the crossing angle α at which the arrangement direction of the light transmission portions of one lens sheet intersects the arrangement direction of the light transmission portions of the other lens sheet is 80 ° ≦ α ≦ 100. Meeting
An imaging module characterized by the above.   An imaging device comprising the imaging module according to any one of claims 1 to 6.

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