JP2016114890A - Lens unit, compound eye optical unit, and compound eye imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens unit that suppresses degradation of an image formation performance of a local facet optical system, resulting from dependency upon an environmental temperature, and to enable highly accurate photographing.SOLUTION: A lens unit comprises: a metal-made intermediate stop 25 that includes a resin-made first lens array 21 on an object side and a resin-made second lens array 22 on an image side, and is fixed by being sandwiched between the first and second lens arrays 21 and 22; a metal-made front stop 29 that is fixed on the object side of the first lens array 21; and a metal-made rear stop 30 that is fixed on the image side of the second lens array. Shear adhesion strength of a first adhesion part 24a between the first lens array 21 and the intermediate stop 25 is smaller than that of a second adhesion part 24b between the second lens array 22 and the intermediate stop 25, or shear adhesion strength of third adhesion part 26 between the second lens array 22 and the rear stop 30 is smaller than that of a fourth adhesion part 27 between the first lens array 21 and the front stop 29.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a lens unit having a lens array in which a plurality of single-lens lenses are formed in a direction orthogonal to the optical axis, a compound-eye optical system unit including the lens unit, and a compound-eye imaging apparatus incorporating the lens unit.

  In recent years, there has been an increasing demand for low profile and high performance for imaging optical systems of portable terminals. In response to these requirements, imaging using a so-called super-resolution technique, in which a plurality of images are taken using a compound eye imaging optical system in which a plurality of single-eye optical systems are arranged in an array and reconstructed into one image Equipment has been developed. Such an imaging device is small and thin, but can reconstruct an image obtained by a plurality of single-eye optical systems, thereby creating a high-resolution image from a plurality of low-resolution images. .

  Here, the single-eye optical system is generally composed of a plurality of lenses to ensure performance. Thus, when each single-eye optical system is composed of a plurality of lenses, in consideration of ease of manufacturing, a laminated compound-eye imaging optical system in which a plurality of lens arrays are laminated and joined is used. However, when the lens array is formed of a resin material, and the diaphragm that is interpolated or the diaphragm that is disposed on the image side or the object side is formed of metal, depending on the way of joining, a laminated compound eye imaging optical system may be used. A relatively large warp may occur in each lens array due to a change in the ambient temperature, and there is a difference in the imaging state between the central one and the peripheral one of the plurality of single-eye optical systems. there is a possibility. In addition, when the sensor body of the imaging device is fixed to the board, the sensor body and the board have different linear expansion coefficients, so the sensor body may be warped when the temperature changes, and the imaging surface may be curved. Even if the focus position of the eye lens is constant when viewed from the lens side, there is a possibility that an effective focus shift may occur between the center side and the peripheral side.

  As a method of laminating a plurality of lens arrays, for example, a method of joining a plurality of lens arrays via an intermediate plate provided with a plurality of openings at positions corresponding to the lenses is known (for example, see Patent Document 1). . This patent document 1 relates to a technique of separating a plurality of lens arrays into individual lenses and does not assume use in the state of a laminated compound eye imaging optical system. It is not premised on a situation in which imaging performance deteriorates in a local single-eye optical system in an environment where the compound-eye imaging optical system and sensor tend to warp due to temperature changes.

JP 2003-329808 A

  It is an object of the present invention to provide a lens unit that enables high-precision imaging by suppressing deterioration of the imaging performance of a local single-eye optical system depending on the environmental temperature.

  It is another object of the present invention to provide a compound eye optical system unit and a compound eye imaging device incorporating the lens unit.

  In order to achieve the above object, a lens unit according to the present invention is made of a resin including a plurality of lens arrays formed by integrating a plurality of single-lens lenses that form a single-eye image on a photoelectric conversion unit of an image sensor. The lens unit includes a first lens array on the object side and a second lens array on the image side as a plurality of lens arrays, and is fixed by being sandwiched between the first lens array and the second lens array. An intermediate light shielding member made of metal, a first light shielding member made of metal fixed to the object side of the first lens array, a second light shielding member made of metal fixed to the image side of the second lens array, The shear adhesive strength of the first adhesive portion between the first lens array and the intermediate light shielding member is smaller than the shear adhesive strength of the second adhesive portion between the second lens array and the intermediate light shielding member, or A two-lens array and a second light-shielding member Shear strength of the third adhesive portion between the smaller shear bond strength of the fourth adhesive portion between the first lens array and the first light blocking member.

  According to the above lens unit, the shear strength of the first or second adhesive portion on the image side of the first or second lens array is relatively small, and is convex toward the image side when the temperature changes with respect to normal temperature. The lens unit tends to warp. That is, the entire lens unit is warped so as to be convex toward the image side due to the first lens array being curved as the temperature rises due to the difference in shear strength of the former, and the temperature rises due to the difference in shear strength of the latter. Along with this, the second lens array is curved, so that the whole lens unit receives a warping force so as to be convex toward the image side. Thus, by utilizing the fact that the stress that warps the lens unit due to the difference in shear strength is utilized, the phenomenon of rear pinning at the peripheral portion as the temperature rises can be offset. In other words, even if the focus position of each single-lens lens shifts due to rear focusing when the temperature rises, the lens unit is warped to compensate for the focus shift by controlling the adhesion balance between the lens array and the light shielding member. By generating the stress, the focus can be adjusted appropriately. Examples of the occurrence of rear pinning at the periphery of the lens unit when the temperature rises include the case where imbalance occurs when two light shielding members are bonded to the image side of the second lens array, or the image sensor itself changes due to temperature changes. There may be warping.

  In a specific aspect or aspect of the present invention, in the above lens unit, when the shear adhesive strength of the first adhesive portion is smaller than the shear adhesive strength of the second adhesive portion, the Young's modulus of the adhesive forming the first adhesive portion Is smaller than the Young's modulus of the adhesive forming the second adhesive portion. Here, the Young's modulus is a physical property value as a material of the adhesive. In this case, by selecting an appropriate adhesive, it is possible to cancel out the focus shift of the peripheral portion of the lens unit described above by using the bending tendency of the first lens array due to a temperature rise or the like.

  In another aspect of the present invention, when the shear adhesive strength of the third adhesive portion is smaller than the shear adhesive strength of the fourth adhesive portion, the Young's modulus of the adhesive forming the third adhesive portion forms the fourth adhesive portion. Smaller than the Young's modulus of the adhesive. In this case, by selecting an appropriate adhesive, it is possible to cancel out the focus shift of the peripheral portion of the lens unit described above by utilizing the bending tendency of the second lens array due to a temperature rise or the like.

  In still another aspect of the present invention, when the shear adhesive strength of the first adhesive portion is smaller than the shear adhesive strength of the second adhesive portion, the adhesive area of the first adhesive portion is smaller than the adhesive area of the second adhesive portion. . In this case, the above-described defocusing of the peripheral portion of the lens unit can be canceled using the bending tendency of the first lens array due to a temperature rise or the like.

  In still another aspect of the present invention, when the shear adhesive strength of the third adhesive portion is smaller than the shear adhesive strength of the fourth adhesive portion, the adhesive area of the third adhesive portion is smaller than the adhesive area of the fourth adhesive portion. . In this case, the above-described defocusing of the peripheral portion of the lens unit can be canceled using the bending tendency of the second lens array due to a temperature rise or the like.

  In still another aspect of the present invention, the plurality of lens arrays is composed of two lens arrays.

  In still another aspect of the present invention, a third light-shielding member made of metal fixed to the image side of the second light-shielding member is provided. In this case, the lens unit is likely to warp when the temperature changes, and rear pinning tends to occur in the peripheral portion particularly when the temperature rises.However, as described above, the temperature can be controlled by controlling the adhesion balance between the lens array and the light shielding member. The focus shift of each individual lens at the time of change can be balanced between the center and the periphery.

  In order to achieve the above object, a compound eye optical system unit according to the present invention includes the lens unit described above and a holder for storing the lens unit.

  According to the above compound-eye optical system unit, rear focusing tends to occur at the periphery of the lens unit when the temperature rises, but the focus shift is balanced between the center and the periphery by controlling the adhesion balance between the lens array and the light shielding member. Can be made. Thereby, it becomes a compound eye optical system unit by which the focus shift by the temperature change was suppressed.

  In order to achieve the above object, a compound eye imaging apparatus according to the present invention includes the compound eye optical system unit described above and an imaging element disposed on the image side of the lens unit.

  According to the above compound-eye imaging device, rear pinning tends to occur at the periphery of the lens unit when the temperature rises, but the focus deviation is balanced between the center and the periphery by controlling the adhesion balance between the lens array and the light shielding member. be able to. Thereby, it becomes a compound eye imaging device by which the focus shift by the temperature change was suppressed.

  In another aspect of the present invention, in the compound eye imaging device, the imaging element warps so as to be concave toward the lens unit when the temperature rises. In this case, it is possible to correct the focus shift of each individual lens at the time of temperature change by utilizing the above-mentioned curve tendency of the lens unit.

(A) is a top view of the compound eye imaging optical system which comprises the compound eye imaging device of 1st Embodiment of this invention, (B) is a sectional side view of the compound eye optical system unit shown to (A). . It is a disassembled perspective view explaining the structure of a compound eye optical system unit. (A) is a plan view (back view) of the first lens array, and (B) is a plan view (front view) of the second lens array. It is a top view (surface view) of an intermediate stop. It is a top view (back view) of a front diaphragm. (A) is a plan view (surface view) of the first rear stop, and (B) is a plan view (surface view) of the second rear stop. (A)-(D) is a figure explaining the curved state of a lens array etc. at the time of a temperature change. (A)-(D) is a figure explaining the curved state of a lens array etc. at the time of a temperature change. It is a figure explaining the compound eye imaging system carrying the imaging device of FIG. (A) is a top view (back view) explaining the 1st adhesion part etc. of a 2nd embodiment, and (B) is a top view (surface view) explaining the 2nd adhesion part etc. It is a sectional side view of the compound eye optical system unit of 4th Embodiment. (A) And (B) is a figure explaining the curved state of an image pick-up element etc. at the time of a temperature change.

[First Embodiment]
Hereinafter, specific embodiments of a lens unit and a compound eye imaging device according to the present invention will be described in detail with reference to the drawings.

  A compound-eye imaging apparatus 100 shown in FIG. 1A or the like is for capturing a plurality of images using a plurality of imaging lenses (that is, a plurality of single-eye optical systems 20s). Note that FIG. 1B shows a cross section taken along the line AA in the plan view shown in FIG. The compound-eye imaging apparatus 100 has a rectangular outer shape, and includes a lens unit 70, a filter 40, a sensor unit 50 (shown by a broken line in FIG. 1B), and a holder 60. Among these, the compound unit optical system unit 200 is configured by storing the lens unit 70 and the filter 40 in the holder 60. In the description of the present embodiment, the rectangular outer shape includes a square as well as a rectangle. Further, in the drawings other than FIG. 1B in FIG. 1, FIG. 2, etc., the compound eye optical system unit 200 of the compound eye imaging device 100 is shown, and the sensor unit 50 is omitted.

  The lens unit 70 includes a lens array stack 20, a front diaphragm 29 (first light shielding member), and a rear diaphragm 30. The lens array stacked body 20 in the lens unit 70 forms a plurality of subject images. For example, as shown in FIG. 2, the lens array stacked body 20 includes a first lens array 21, a second lens array 22, and a plate-shaped intermediate diaphragm 25 (intermediate light shielding member). The lens arrays 21 and 22 and the intermediate diaphragm 25 are stacked in the direction of the optical axis AX (see FIG. 1B). The lens array stacked body 20 has a function of individually forming a plurality of subject images on a plurality of imaging surfaces (projected surfaces) provided in the sensor unit 50 as single-eye images. In the present embodiment, the lens array laminate 20 itself may be referred to as a compound eye optical system. In addition, the entire lens array stack 20 may be simply referred to as a lens array.

  The first lens array 21 in the lens array stacked body 20 is arranged on the most object side. The first lens array 21 is a resin molded product in which a plurality of first eye lenses 121 that are two-dimensionally arranged in a direction perpendicular to the optical axis AX are connected, and has a rectangular outer shape. The first lens array 21 is made of, for example, polycarbonate or acrylic. In the illustrated example, there are a total of 16 first eye lenses 121 arranged in a matrix of 4 rows and 4 columns. Each first single lens 121 has a first lens body 21a and a first flange 21b. Adjacent first single-lens lenses 121 are connected and integrated via the first flange portion 21b. A portion obtained by combining all the first flange portions 21b serves as a support body 21y that supports the first lens body portion 21a. The support 21y has a flat plate shape and extends parallel to the XY plane. The first lens body 21a includes a first optical surface 21c that is a convex aspheric surface on the object side, and a second optical surface 21d that is a concave aspheric surface on the image side.

  The second lens array 22 is disposed on the image side of the first lens array 21. Similar to the first lens array 21, the second lens array 22 is a resin molded product that is two-dimensionally arranged in a direction perpendicular to the optical axis AX and connects a plurality of second eye lenses 122. It has an outer shape. Similar to the first lens array 21, the second lens array 22 is formed of, for example, polycarbonate or acrylic. There are 16 second eye lenses 122 arranged in a matrix of 4 rows and 4 columns. Each second single lens 122 has a second lens body 22a and a second flange 22b. The adjacent second eye lenses 122 are connected and integrated through the second flange portion 22b. A portion obtained by combining all the second flange portions 22b is a support body 22y that supports the second lens body portion 22a. The support 22y has a flat plate shape and extends parallel to the XY plane. The second lens body 22a includes a third optical surface 22c that is a concave aspheric surface on the object side, and a fourth optical surface 22d that is a convex aspheric surface on the image side.

  One first eye lens 121 constituting the first lens array 21 and the second eye lens 122 arranged on the same optical axis AX on the second lens array 22 side independently generate an object image. It functions as one imaging lens to be formed, that is, as a single-eye optical system 20s that enables imaging alone. In other words, the pair of individual lenses 121 and 122 that are adjacent to each other in the direction of the optical axis AX and function as the single-eye optical system 20s. In the entire lens array laminate 20, there are 4 × 4 single-eye optical systems 20 s arranged on lattice points.

  The first and second lens arrays 21 and 22 are integrally molded products made of resin, and are molded by, for example, injection molding using a mold, press molding using a mold or a resin mold, or cast molding.

  The first lens array 21 and the second lens array 22 are laminated via an intermediate diaphragm 25 and an intermediate bonding portion 24. The intermediate bonding portion 24 is a first bonding portion 24a provided in the region of the first flange portion 21b on the first lens array 21 side and a second bonding portion provided in the region of the second flange portion 22b on the second lens array 22 side. The intermediate diaphragm 25 is sandwiched between the first and second adhesive portions 24a and 24b. The intermediate bonding portion 24 is formed of, for example, a photo-curing resin having a light shielding property due to absorption. For example, a black inorganic pigment or an organic pigment is added to the photocurable resin for the purpose of securing light shielding properties by absorption.

  The first adhesive portion 24a includes, on the object side of the intermediate diaphragm 25, a first lens main body portion 21a constituting each first single-lens lens 121 in the first lens array 21, and a first lens main body portion 21a adjacent thereto. , That is, in the region of the first flange portion 21b.

  Specifically, as illustrated in FIG. 3A, the first adhesive portion 24 a spreads in a lattice shape corresponding to the lattice-shaped portion extending between the plurality of first single-eye lenses 121. However, as shown in FIG. 4, the first adhesive portion 24 a does not spread over the rectangular outer peripheral region 25 r corresponding to the outer frame in the intermediate aperture 25. In other words, in the case of the first lens body 21a disposed in the non-peripheral region NP on the center side, the periphery in the lateral direction perpendicular to the optical axis AX is caused by the frame-shaped adhesive region NPa that is a part of the first adhesive portion 24a. Surrounded by On the other hand, in the case of the first lens main body portion 21a arranged on the peripheral side, that is, other than the non-peripheral region NP, the first adhesive portion 24a is surrounded in two or three directions but is partially opened. It has become.

  The second adhesive portion 24b includes, on the image side of the intermediate diaphragm 25, a second lens main body portion 22a that constitutes each second single lens 122 in the second lens array 22, and a second lens main body adjacent thereto. It is provided between the portions 22a, that is, in the region of the second flange portion 22b.

  Specifically, as illustrated in FIG. 3B, the second adhesive portion 24 b extends in a lattice shape corresponding to the lattice-shaped portion extending between the plurality of single-eye lenses 122. However, the second adhesive portion 24b does not extend to the outer peripheral region 25r of the intermediate diaphragm 25, like the first adhesive portion 24a. That is, in the case of the second lens main body portion 22a disposed in the non-peripheral region NP on the center side, the periphery in the lateral direction perpendicular to the optical axis AX by the frame-shaped adhesive region NPa that is a part of the second adhesive portion 24b. Surrounded by On the other hand, in the case of the second lens main body portion 22a arranged on the peripheral side, that is, outside the non-peripheral region NP, the second lens main body portion 22a is surrounded by the second adhesive portion 24b from two or three directions, but is partially opened. It has become. Thus, it is preferable that the 1st adhesion part 24a and the 2nd adhesion part 24b become the same shape pattern, when projected in the optical axis AX direction. In the present embodiment, the bonding area of the first bonding portion 24a is substantially the same as the bonding area of the second bonding portion 24b.

  The intermediate diaphragm 25 is a rectangular and plate-shaped diaphragm member (diaphragm plate), and is joined to the first and second lens arrays 21 and 22 via the first and second adhesion parts 24a and 24b of the intermediate adhesion part 24. ing. For example, as shown in FIGS. 2 and 4, in the intermediate aperture 25, circular openings 25a are formed at positions corresponding to the first and second lens body portions 21a and 22a of the first and second lens arrays 21 and 22. Is formed. The intermediate diaphragm 25 is a plate-like member made of metal, and the surface is painted or surface-treated in black or dark color.

  As shown in FIG. 1 (B), FIG. 2 and the like, the holder 60 is a member made of a black resin and having a top surface portion 61 and a side wall portion 62, and has a bowl-like or box-like outer shape as a whole. Have. The holder 60 is formed with a recess 60a having a plurality of steps. The holder 60 is formed with a circular opening 60b at lattice point positions corresponding to the plurality of optical surfaces of the lens array laminate 20. The holder 60 is formed of a light-shielding resin, for example, acrylic containing a colorant such as a black pigment, liquid crystal polymer (LCP), polyphthalamide (PPA), or the like.

  As shown in FIGS. 1B and 2, the front diaphragm 29 is a rectangular plate-like member provided between the holder 60 and the lens array stacked body 20. A circular opening 29a is formed in the front diaphragm 29 at a position corresponding to the first and second lens main body portions 21a and 22a of the first and second lens arrays 21 and 22.

  As shown in FIGS. 1B and 5, the first lens array 21 and the front aperture stop 29 are stacked with a fourth adhesive portion 27 interposed therebetween. As the fourth bonding portion 27, the same one as the intermediate bonding portion 24 can be used.

  As shown in FIG. 5, the fourth adhesive portion 27 extends in a frame shape so as to surround the periphery of the outermost first single-eye lens 121. The fourth adhesive portion 27 does not spread in the inner region where the first single-lens 121 is disposed. In other words, the fourth adhesive portion 27 extends to a rectangular outer peripheral region 29r corresponding to the outer frame in the front diaphragm 29.

  As shown in FIG. 1B, FIG. 2, and the like, the rear diaphragm 30 includes a first rear diaphragm 31 (second light shielding member) and a second rear diaphragm 32 (third light shielding member). The first and second rear stops 31 and 32 are rectangular plate-like members provided between the lens array laminate 20 and the filter 40. Of the rear diaphragm 30, the first rear diaphragm 31 is provided on the object side, and the second rear diaphragm 32 is provided on the image side. In other words, the second rear stop 32 is an image side stop located closest to the image side among the stops 29, 25, 31, 32.

  As shown in FIGS. 2 and 6A, in the first rear diaphragm 31 among the rear diaphragm 30, the first and second lens body portions 21a and 22a of the first and second lens arrays 21 and 22 are provided. A circular opening 31a is formed in accordance with the shape of the lens at a position corresponding to.

  2 and 6B, on the other hand, in the second rear diaphragm 32 in the rear stage among the rear diaphragm 30, the first and second lens body portions 21a of the first and second lens arrays 21 and 22 are provided. , 22a, a rectangular opening 32a is formed in accordance with the sensor unit 50 (see FIG. 1B).

  The first and second rear diaphragms 31 and 32 constituting the rear diaphragm 30 can be made of the same material as the intermediate diaphragm 25. The first and second rear stops 31 and 32 have a field stop function of each individual optical system 20 s and block stray light incident on the sensor unit 50. Here, in the present embodiment, in particular, the second rear stop 32 that is an image side stop is the second lens array 22 (or the second lens array 22 in the direction perpendicular to the optical axis AX (see FIG. 1B)). The lens array stacked body 20) including the flange portion SG is formed to extend larger than the lens array stacked body 20). The second rear diaphragm 32 is bonded to the second lens array 22 in the bowl-shaped portion SG.

  The second lens array 22 and the rear diaphragm 30 are stacked via the third adhesive portion 26. Specifically, the third adhesive portion 26 includes a third front adhesive portion 26 a provided between the second lens array 22 and the first rear diaphragm 31, and the second lens array 22 and the second rear diaphragm 32. It is comprised with the 3rd back adhesion part 26b provided in between. The same thing as the middle adhesion part 24 can be used for the 3rd adhesion part 26.

  As shown in FIGS. 6A and 6B, the third front adhesive portion 26a and the third rear adhesive portion 26b spread in a frame shape so as to surround the periphery of the outermost second eye lens 122. Yes. The third front adhesive portion 26a and the third rear adhesive portion 26b do not spread over the inner region where the second eye lens 122 is disposed. In other words, the third front adhesive portion 26a and the third rear adhesive portion 26b are spread in rectangular outer peripheral areas 31r and 32r corresponding to outer frames in the first and second rear diaphragms 31 and 32, respectively.

  In the present embodiment, the shear strength of the third adhesive portion 26 between the second lens array 22 and the rear diaphragm 30 is the shear strength of the fourth adhesive portion 27 between the first lens array 21 and the front diaphragm 29. It is almost the same as the strength.

  The filter 40 is a rectangular plate-like member, and is provided between the rear diaphragm 30 and the sensor unit 50. The filter 40 is, for example, an IR cut filter (infrared cut filter) having a function of reflecting infrared rays. The filter 40 is fixed not to the second lens array 22 but to a part or the whole of the outer frame of the holder 60.

  A sensor unit 50 shown in FIG. 1B is an imaging device, and an imaging unit (not shown) that individually detects a plurality of subject images formed by the individual eye optical systems 20s constituting the lens array stacked body 20. ). The sensor unit 50 is fixed not to the second lens array 22 but to a part or the whole of the outer frame of the holder 60. A photoelectric conversion unit (not shown) provided in the sensor region 51 constituting the imaging unit is composed of a CCD or a CMOS, photoelectrically converts incident light, and outputs an analog signal thereof. The surface of the sensor element or the photoelectric conversion unit is an imaging surface (projected surface). The sensor unit 50 is covered with, for example, a cover glass on the front side, and is fixed on the back side with a wiring board (not shown). The wiring board receives supply of a voltage and a signal for driving the imaging unit from an external circuit, and outputs a detection signal to the external circuit. In addition, the sensor part 50 of this embodiment is different from the case of 4th Embodiment mentioned later, and uses the thing which does not curve-deform at the time of a temperature change.

  Hereinafter, the adhesion balance between the first and second lens arrays 21 and 22 and the diaphragms 25, 29, 31, and 32 will be described.

  In general, as shown in FIG. 7A, the plastic lens array L1 and the metal diaphragm T1 are fixed with an adhesive. When these are bonded in a lattice shape or a frame shape along the entire circumference of the lens array L1, the lens array L1 and the diaphragm T1 are relatively strongly restrained. When the temperature is changed in this state, the lens array L1 extends from the diaphragm T1 at a high temperature as shown in FIG. 7B due to the difference in expansion and contraction between the lens array L1 and the diaphragm T1. Thus, it is curved and deformed convexly on the surface to which the diaphragm T1 is not bonded. On the other hand, when the temperature is low, as shown in FIG. 7C, the lens array L1 is contracted from the diaphragm T1 and curved and deformed convexly on the surface to which the diaphragm T1 is bonded. If the adhesive forming the bonding portion for bonding the lens array L1 and the diaphragm T1 is bonded in a dot shape instead of a lattice shape or a frame shape, only the diaphragm T1 is deformed, so that the warp of the lens array L1 is reduced. Adhesive strength is weakened, making it difficult to withstand the drop impact of the lens unit. Therefore, as described above, it is necessary to increase the bonding area like a lattice shape or a frame shape. Here, as shown in FIG. 7D, if the diaphragms T1 and T2 are bonded to both surfaces of the lens array L1, and the restraint state by bonding is equivalent, the bonding strength can be balanced even at high or low temperatures. Although the lens array does not warp, even in this case, if the adhesive strength with one of the apertures T1 and T2 is weak, the balance of the adhesive strength is lost, and the lens array L1 warps. Further, as shown in FIG. 8A, in the case of the lens array laminate LL in which the intermediate diaphragm T3 is provided between the two lens arrays L1 and L2, the adhesive strength between the lens array L1 and the intermediate diaphragm T3. If the lens array L1 is relatively weaker than the other, as shown in FIG. 8B, for example, the lens array L1 warps so as to be convex toward the image side at a high temperature, and the other lens array L2 is also affected by the effect of the warp Warps to the image side. As a result, the lens array stacked body LL is curved and deformed so as to be convex toward the image side as a whole. In this case, it becomes a state of front pinning in the peripheral part of the lens array laminated body LL. Similarly, when the adhesive strength between the lens array L2 and the outer diaphragm T1 is relatively weaker than the other, for example, the lens array L2 warps so as to be convex toward the image side at a high temperature, and the influence of the other causes The lens array L1 also warps to the image side. As a result, the lens array stacked body LL is curved and deformed so as to be convex toward the image side as a whole.

  The individual lens lenses M1 and M2 are imaged on the corresponding sensor surfaces U by the joined lens arrays L1 and L2, and a desired image is obtained. When a light beam that has passed through a single lens M1, M2 reaches the adjacent sensor surface U, there is an adverse effect such as a ghost image, and the light beam that has passed through the single lens M1, M2 is converted into a single lens M1, M2. It is necessary to separate each. Therefore, as shown in FIG. 8C, it is necessary to provide image-side stops T1 and T4 (rear stop 30 in FIG. 1B). In this case, in order to efficiently divide the light beam with the plate-like member, it is preferable to cut the light beam at two places, immediately after the single-eye lens M2 and in the vicinity of the sensor. For this reason, in this embodiment, as described above with reference to FIG. 1B, two rear diaphragms 30 are provided. In addition, since only harmful light is cut and light rays that contribute to image formation are not cut, it is necessary to determine the positions of the individual lenses M1 and M2 and the stops T1 and T4 with high accuracy. The stops T1 and T4 are directly connected to the lens array. It is necessary to bond. One lens-side stop T2 (the front stop 29 in FIG. 1B) and two image sides with respect to the lens array laminate LL composed of two lens arrays L1 and L2 and an intermediate stop T3 When the diaphragms T1 and T4 (rear diaphragm 30) are bonded, the shear strength on the image side diaphragms T1 and T4 increases when the temperature changes. For example, as shown in FIG. On the other hand, the focus surfaces of the individual lenses M1 and M2 are curved surfaces. That is, it becomes a state of rear pinning around the lens array stacked body LL. Like the lens unit 70 of the present embodiment, the bonding strength of the first and second bonding portions 24a and 24b is set to the peripheral portion of the lens unit at other portions (in the present embodiment, the lens arrays 21 and 22 and the intermediate diaphragm 25). Therefore, the lens unit 70 is flattened by canceling the warp of the lens unit 70 at the time of temperature change, and the focus shift can be canceled. Thereby, even if it combines with the sensor part 50 which does not curve at the time of a temperature change, the focus fluctuation | variation between the 1st and 2nd eye-lens 121,122 can be suppressed.

  In the lens unit 70 of the present embodiment, the shear adhesive strength of the first adhesive portion 24 a between the first lens array 21 and the intermediate aperture 25 is the second adhesive portion between the second lens array 22 and the intermediate aperture 25. It is smaller than the shear bond strength of 24b. As described above, the warp of the entire lens unit 70 is changed by the difference in shear strength between the lens arrays 21 and 22 and the intermediate diaphragm 25. Here, since it is difficult to directly measure the shear strength, the shear strength is evaluated based on the degree of warping of the lens unit 70. That is, the magnitude relationship of the shear strength can be known by estimating with an index reflecting the degree of warping of the lens unit 70. In the present embodiment, the difference in shear strength between the first adhesive portion 24a and the second adhesive portion 24b is caused by the difference in Young's modulus between the adhesives constituting the first and second adhesive portions 24a and 24b. Specifically, the Young's modulus of the adhesive that forms the first adhesive portion 24a is smaller than the Young's modulus of the adhesive that forms the second adhesive portion. Here, the Young's modulus is a physical property value as a material of the adhesive. By selecting an appropriate adhesive, it is possible to adjust the warpage of the lens unit 70 due to the curvature of the first lens array 21 when the temperature changes.

  Hereinafter, a compound eye imaging system 300 equipped with the compound eye imaging device 100 will be described with reference to FIG.

  The compound eye imaging system 300 includes the compound eye imaging device 100, a drive processing unit 81, and a display 83. Here, an electrical signal from each sensor region 51 (see FIG. 1B) provided in the sensor unit 50 of the compound-eye imaging device 100 is input to the drive processing unit 81. This electrical signal corresponds to each image formed on each sensor region 51. The drive processing unit 81 reconstructs each image into one image by processing the input signal based on a predetermined processing program, and outputs the reconstructed one image to the display 83. Note that the reconstructed image data may be output by connecting to a PC (personal computer) or the like instead of the display 83.

  Hereinafter, an example of a procedure for assembling the lens array laminate 20 to the holder 60 will be described. Here, the adhesive for forming the first and second adhesive portions 24 a and 24 b between the first and second lens arrays 21 and 22 is UV curable, and the first lens array 21 and the front diaphragm 29 are used. It is assumed that the fourth adhesive portion 27, the second lens array 22, and the third adhesive portion 26 between the rear diaphragm 30 are thermosetting adhesives. First, the lens array laminate 20 is formed by adhering the intermediate diaphragm 25 between the first lens array 21 and the second lens array 22. Specifically, a UV curable adhesive is applied in a lattice pattern to a region between the first single-lens lenses 121 on the image side surface of the first lens array 21 (see the lattice in FIG. 3A), and a UV curable adhesive is applied thereon. The intermediate diaphragm 25 is positioned and arranged. Next, a UV curable adhesive is applied in a lattice pattern to an inter-opening region (see the lattice in FIG. 3B) extending between the openings 25a of the intermediate diaphragm 25, and the second lens array 22 is applied thereon. Position and arrange. Thereafter, UV light is irradiated from the object side of the first lens array 21 and the image side of the second lens array 22 while maintaining the relative positional relationship between the first and second lens arrays 21 and 22. The bonding portions 24a and 24b are cured to bond the first and second lens arrays 21 and 22. Thereby, the lens array laminated body 20 is produced. Here, the Young's modulus of the adhesive of the first adhesive portion 24a is smaller than the Young's modulus of the adhesive of the second adhesive portion 24b. Next, the lens unit 70 is formed by adhering the front diaphragm 29 and the rear diaphragm 30 to the lens array stacked body 20. Specifically, a thermosetting adhesive is applied in the shape of a frame around the outermost first lens 121 on the object side surface of the first lens array 21, and the front diaphragm 29 is positioned and disposed thereon. (See FIG. 5). Next, a thermosetting adhesive is applied in a frame shape around the outermost second eye lens 122 on the image side surface of the second lens array 21, and the first rear diaphragm 31 and the second rear diaphragm are formed thereon. 32 are positioned and arranged (see FIGS. 6A and 6B). Thereafter, the third and fourth adhesive portions 26 and 27 are cured by heating while maintaining the relative positional relationship between the members 20, 29, 31 and 32, and the lens array stacked body 20 and the diaphragms 29 and 31. , 32 is bonded. Thereby, the lens unit 70 is produced. Next, while maintaining the object side surface of the lens unit 70 facing downward, the top surface portion 61 of the holder 60 corresponding to the outer peripheral portion of the object side surface of the lens unit 70 with respect to the holder 60 with the top and bottom reversed. After the thermosetting adhesive is applied, the two are brought into contact with each other and heated for adhesion. Next, the filter 40 is bonded to the holder 60. Thereafter, the sensor part 50 is fitted into the lower end of the side wall part 62 of the holder 60, and an adhesive is supplied to an appropriate position in an aligned state and cured by light or heat. That is, the sensor unit 50 is fixed to the holder 60 by an adhesive part obtained by curing the adhesive.

  According to the lens unit and the compound-eye imaging device 100 of the present embodiment, the shear strength of the first adhesive portion 24a on the image side of the first lens array 21 is relatively small, and the image side is on the image side when the temperature changes with respect to the normal temperature. In the convex state, the lens unit tends to warp. Due to the difference in shear strength, the first lens array 21 is bent as the temperature rises, so that the entire lens unit 70 is warped so as to be convex toward the image side. By utilizing the fact that the stress that warps 70 changes, it is possible to cancel the phenomenon of rear pinning at the peripheral portion as the temperature rises. In other words, even if the focus of the individual lenses 121 and 122 is shifted due to rear focusing at the periphery of the lens unit 70 when the temperature rises, the focus shift is compensated by controlling the adhesion balance between the lens array and the light shielding member. Thus, the focus can be adjusted appropriately by generating a stress that warps the lens array.

[Second Embodiment]
Hereinafter, the lens unit and the like of the second embodiment will be described. The lens unit or the like of the second embodiment is a partial modification of the lens unit or the like of the first embodiment, and matters not specifically described are the same as those of the lens unit or the like of the first embodiment.

  In the present embodiment, the difference in shear strength between the first adhesive portion 24a between the first lens array 21 and the intermediate aperture 25 and the second adhesive portion 24b between the second lens array 22 and the intermediate aperture 25 is expressed as follows. It is generated by the difference in the bonding area between the first and second bonding portions 24a and 24b. Specifically, as shown in FIGS. 10A and 10B, the bonding area of the first bonding portion 24a is smaller than the bonding area of the second bonding portion 24b. Accordingly, it is possible to cancel out of focus in the peripheral portion of the lens unit 70 by using the bending tendency of the first lens array 21 when the temperature changes. In addition, it is preferable that the adhesion area of the 1st adhesion part 24a is 1/2 or less of the adhesion area of the 2nd adhesion part 24b.

[Third Embodiment]
Hereinafter, the lens unit of the third embodiment will be described. The lens unit or the like of the third embodiment is a partial modification of the lens unit or the like of the first or second embodiment, and matters not specifically described are the same as those of the lens unit or the like of the first or second embodiment. It is.

  In the present embodiment, the shear strength of the third adhesive portion 26 between the second lens array 22 and the rear aperture 30 is greater than the shear strength of the fourth adhesive portion 27 between the first lens array 21 and the front aperture 29. It is getting smaller. Here, when the rear diaphragm 30 is composed of two sheets, the shear strength of the third adhesive portion 26 is influenced by the shear strength of both the third front adhesive portion 26a and the third rear adhesive portion 26b, and the rear It becomes larger than the shear strength of the third adhesive portion in the case where the diaphragm 30 is constituted by one sheet. The shear strength of the third adhesive portion 26 on the image side of the second lens array 22 decreases, and for example, when the temperature changes, the lens unit tends to warp in a convex state on the image side. That is, due to the difference in shear strength, the entire lens unit is warped so as to be convex toward the image side due to the curvature of the second lens array 22 as the temperature rises. The difference in shear strength is generated by the difference in Young's modulus of the bonded portion as in the first embodiment, for example. Specifically, the Young's modulus of the adhesive constituting the third adhesive portion 26 is smaller than the Young's modulus of the adhesive constituting the fourth adhesive portion 27. Thereby, by selecting an appropriate adhesive, it is possible to cancel out of focus in the peripheral portion of the lens unit 70 by using the bending tendency of the second lens array 22 when the temperature changes. Note that, as in the second embodiment, the difference in shear strength may be generated by the difference in the bonding area of the bonding portion. Specifically, the bonding area of the third bonding portion 26 is made smaller than the bonding area of the fourth bonding portion 27. The bonding area of the third bonding portion 26 is preferably less than or equal to ½ of the bonding area of the fourth bonding portion 27. The shear bonding strength of the third bonding portion 26 may be set by adjusting only one of the third front bonding portion 26a and the third rear bonding portion 26b.

  In the present embodiment, the shear strength of the first adhesive portion 24 a between the first lens array 21 and the intermediate aperture 25 is the shear strength of the second adhesive portion 24 b between the second lens array 22 and the intermediate aperture 25. It is almost the same as the strength.

[Fourth Embodiment]
Hereinafter, the lens unit and the like of the fourth embodiment will be described. The lens unit or the like of the fourth embodiment is a partial modification of the lens unit or the like of the first to third embodiments, and matters not specifically described are the same as those of the lens unit of the first to third embodiments. It is.

  As shown in FIG. 11, in the present embodiment, a sensor unit 50 that is an image sensor uses a sensor that is curved and deformed when the temperature changes. That is, for example, when the temperature rises, the sensor unit 50 according to the present embodiment is bent so as to be displaced in the optical axis AX direction, and is curved so as to be concave on the object side in an arbitrary cross section in a direction perpendicular to the optical axis AX. To do. Therefore, the lens unit 70 includes the first and second lens arrays 21 and 22 and the first to fourth adhesive portions 24a, 24b, 26, and so that stress is generated so as to bend in a convex state toward the image side when the temperature rises. The adhesion balance with 27 is controlled. The lens unit 70 may provide a difference in the shear strength of the first and second adhesive portions 24a and 24b as in the first and second embodiments, or the third and third as in the third embodiment. You may provide a difference in the shear strength of 4 adhesion parts 26 and 27. In the example of FIG. 11, the rear diaphragm 30 does not have the second rear diaphragm and is configured by only one first rear diaphragm 31. However, as described above, the rear diaphragm 30 includes two sheets. You may comprise with an aperture member.

  As shown in FIG. 12A, in an imaging device using a COB (Chip on board) substrate that is inexpensive, the sensor SN and the substrate ST are fixed by adhesion. In general, silicon is used for the sensor SN, and glass epoxy or the like is used for the substrate ST. Since the linear expansion coefficient of the substrate ST is larger than that of silicon, the substrate ST tends to warp in a convex state toward the substrate ST as shown in FIG. In this case, if the focus of the single lens M2 of the lens array L2 is a fixed surface, the distance between the single lens M2 and the sensor surface U is the single lens M2 on the central side and the single lens M2 on the peripheral side. For example, when focusing on the central single lens M2, the peripheral single lens M2 is out of focus. For example, the sensor SN warps in a convex state toward the substrate ST at a high temperature. That is, it becomes a state of rear pinning around the lens array stacked body LL. Therefore, by adjusting the shear strength due to the adhesion between the lens arrays L1 and L2 and the diaphragms T1 to T4 so that the focus shift at the periphery of the lens unit cancels out, the focus shift at the time of temperature change can be canceled.

  As mentioned above, although this invention was demonstrated according to embodiment and an Example, this invention is not limited to the said embodiment etc. For example, the arrangement of the single-eye optical system 20s is not limited to 4 × 4, but may be 3 × 3 or 5 × 5 or more. Further, the single-eye optical system 20s is not limited to being arranged at rectangular lattice points, and various arrangement patterns can be used.

  In the above embodiment, the rear diaphragm 30 is composed of two sheets, but the phenomenon in which the lens unit 70 warps when the temperature changes occurs similarly when the strength of the metal diaphragm is strong. For example, a state where the strength of the diaphragm is strong is, for example, a case where the number of the rear diaphragm 30 is one, but it is thick.

  In the above embodiment, the case where the lens unit 70 or the sensor unit 50 (imaging device) is curved and deformed when the temperature is changed has been described, but both the lens unit 70 and the sensor unit 50 may be curved and deformed. In this case, the difference in shear strength between the bonding portions 24a, 24b, 26, and 27 is adjusted so as to generate a stress that warps the lens unit so as to compensate for the focus shift.

  In the said embodiment, although the pattern of the 3rd and 4th adhesion parts 26 and 27 was made into frame shape, you may change into another pattern.

  In the above-described embodiment, the lens array laminate 20 may have a structure in which an intermediate diaphragm (aperture plate) is inserted and joined between three stacked lens arrays.

  In the above embodiment, each single-eye optical system 20s constituting the lens array stacked body 20 is a super-resolution type that images the same field, but each single-eye optical system 20s is a field division type that images different fields of view. You can also.

  In the above embodiment, the sensor unit 50 is directly fixed to the holder 60. However, a lower housing that holds the sensor unit 50 may be provided, and the lower housing and the holder 60 may be joined.

  In the above embodiment, the first and second adhesive portions 24a and 24b are not only the periphery of the first and second lens main body portions 21a and 22a arranged in the non-peripheral region NP on the center side, but also the intermediate diaphragm 25. It can also be formed in the outer peripheral region 25r. In this case, all the single-lens lenses are in a state surrounded by a frame-shaped adhesive region.

  AX ... optical axis, 20 ... lens array laminate, 20s ... single-eye optical system, 21,22 ... lens array, 21a, 22a ... lens body, 21b, 22b ... flange, 21c, 21d ... optical surface, 24, 24a, 24b, 26, 26a, 26b, 27 ... glue part, 40 ... filter, 50 ... sensor part, 60 ... holder, 70 ... lens unit, 100 ... compound eye imaging device, 121, 122 ... single lens, 200 ... compound eye Optical system unit, 300 ... Compound eye imaging system

Claims (10)

A resin lens unit including a plurality of lens arrays formed by integrating a plurality of single-lens lenses that form a single-eye image on a photoelectric conversion unit of an image sensor,
The plurality of lens arrays includes a first lens array on the object side and a second lens array on the image side,
An intermediate light shielding member made of metal that is sandwiched and fixed between the first lens array and the second lens array;
A first metal light-shielding member fixed to the object side of the first lens array;
A metal second light-shielding member fixed to the image side of the second lens array;
With
The shear adhesive strength of the first adhesive portion between the first lens array and the intermediate light shielding member is smaller than the shear adhesive strength of the second adhesive portion between the second lens array and the intermediate light shielding member, or The shear strength of the third adhesive portion between the second lens array and the second light shielding member is smaller than the shear adhesive strength of the fourth adhesive portion between the first lens array and the first light shielding member. Lens unit characterized by   When the shear adhesive strength of the first adhesive portion is smaller than the shear adhesive strength of the second adhesive portion, the Young's modulus of the adhesive forming the first adhesive portion is the adhesive forming the second adhesive portion. The lens unit according to claim 1, wherein the lens unit is smaller than the Young's modulus.   In the case where the shear adhesive strength of the third adhesive portion is smaller than the shear adhesive strength of the fourth adhesive portion, the Young's modulus of the adhesive forming the third adhesive portion is the adhesive forming the fourth adhesive portion. The lens unit according to claim 1, wherein the lens unit has a Young's modulus smaller than that of the agent.   When the shear adhesive strength of the first adhesive portion is smaller than the shear adhesive strength of the second adhesive portion, the adhesive area of the first adhesive portion is smaller than the adhesive area of the second adhesive portion. The lens unit according to claim 1.   When the shear adhesive strength of the third adhesive portion is smaller than the shear adhesive strength of the fourth adhesive portion, the adhesive area of the third adhesive portion is smaller than the adhesive area of the fourth adhesive portion. The lens unit according to claim 1.   The lens unit according to any one of claims 1 to 5, wherein the plurality of lens arrays includes two lens arrays.   The lens unit according to claim 1, further comprising a metal third light-shielding member fixed to the image side of the second light-shielding member. The lens unit according to any one of claims 1 to 7,
A compound eye optical system unit comprising a holder for storing the lens unit. A compound eye optical system unit according to claim 7;
An image sensor disposed on the image side of the lens unit;
A compound eye imaging apparatus comprising:   The compound-eye imaging device according to claim 9, wherein the imaging element warps so as to be concave toward the lens unit when the temperature rises.

Images