JP2011154058A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of suppressing deformation of a lens holding frame member in an optical axis direction even when ambient temperature is varied. <P>SOLUTION: Four rib parts 22a to 22d having each length that they are located to the vicinity of a center part from an image sensor side end on an outer surface of the lens holding frame member 21 formed in a lens cell 20 are integrally connected between with an inner wall surface of a substrate fixed part 23. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus used for a vehicle-mounted camera such as a digital still camera or a back monitor camera mounted on a vehicle.

  An imaging device composed of a housing in which a solid-state imaging device such as an imaging optical system and a CCD image sensor is incorporated is used for a digital still camera and the like, and in recent years, it is also used for a vehicle-mounted camera and the like such as a back monitor camera. It has been.

  An image pickup apparatus used for a vehicle-mounted camera such as a back monitor camera generally has a lens holding frame member holding an image pickup lens system in a casing as an exterior, a CCD image sensor arranged on the optical axis of the image pickup lens system, etc. The substrate on which the solid-state image sensor is arranged is positioned and fixed (for example, see Patent Document 1). In the imaging device of Patent Document 1, the outer peripheral end surface on the rear end side (substrate side) of the lens holding frame member is fixed to the front end surface of the substrate with an adhesive. The lens holding frame member and the substrate are formed of synthetic resin materials having different linear expansion coefficients.

  By the way, when using an imaging device like the said patent document 1 as a vehicle mounting camera, for example as a back monitor camera, since it arrange | positions in the vehicle body rear part of a vehicle (automobile), the influence of the use environment temperature of a vehicle (automobile). Receive greatly. For this reason, when the lens holding frame member fixed to the front end surface of the substrate with an adhesive is deformed due to a change in environmental temperature, the subject image incident through the imaging lens system is placed on the light receiving surface of the solid-state imaging device. Even if it is adjusted at the time of shipment from the factory so as to form an image with high accuracy, this imaging position shifts with respect to the optical axis direction, and there is a problem that the image is out of focus (out of focus).

  In particular, a vehicle-mounted camera such as a back monitor camera is formed in a small shape, and has a substrate fixed to the rear end side (solid-state imaging device side) of a lens holding frame member holding an imaging lens system with an adhesive. Since the distance between them is very short, the lens holding frame member is greatly affected by deformation due to fluctuations in the environmental temperature.

  Therefore, an object of the present invention is to provide an imaging device that can suppress deformation of the lens holding frame member even when the environmental temperature fluctuates.

  In order to achieve the above object, an imaging apparatus according to claim 1 is imaged by a casing constituting an exterior, an imaging lens system holding member holding an imaging optical system in the casing, and the imaging optical system. An imaging apparatus comprising: a substrate on which an imaging element for photoelectrically converting a subject image to be placed is disposed on a front side; and a substrate fixing member that fixes the substrate to a rear side on the back side of the imaging optical system holding member. It is characterized in that at least an outer surface of the image sensor side end portion of the system holding member and an inner wall surface of the substrate fixing member are integrally connected by a rib portion.

  The imaging device according to claim 2, wherein the rib portion is formed so as to be located from an end portion on the imaging element side of the imaging optical system holding member to a vicinity of a central portion in a longitudinal direction of the imaging optical system holding member. It is characterized by being.

  The imaging device according to claim 3, wherein the rib portion is an end portion on the opposite side to the imaging element along a longitudinal direction of the imaging optical system holding member from the imaging element side end portion of the imaging optical system holding member. It is characterized by being formed so as to be located up to the vicinity.

  The imaging apparatus according to claim 4, wherein the substrate and the substrate fixing member are an indirect adhesion structure in which the substrate and the substrate fixing member are bonded via a bonding intermediate member, and a filling adhesion structure in which an adhesive is filled between the substrates and the bonding member. It is characterized by being joined by.

  The imaging device according to claim 5 is characterized in that a plurality of the rib portions are provided at a predetermined interval with respect to a circumferential direction of the imaging optical system holding member.

  The imaging apparatus according to claim 6, wherein an imaging optical system holding member that holds an imaging optical system composed of a plurality of lenses, and an imaging device that photoelectrically converts a subject image formed by the imaging optical system And a substrate fixing member that fixes the substrate, and is made to correspond to the position of the lens most affected by the environmental temperature among the plurality of lenses constituting the imaging optical system. In addition, the outer surface of the lens holding frame body and the substrate fixing member are connected by a rib portion.

  According to the imaging apparatus of the present invention, since at least the outer surface of the imaging element side end portion of the imaging optical system holding member and the inner wall surface of the substrate fixing member are integrally connected by the rib portion, the imaging optical system holding The strength along the longitudinal direction in the vicinity of the end of the member on the image sensor side can be further increased. Therefore, even when the environmental temperature changes greatly, the occurrence of thermal deformation of the imaging optical system holding member can be reduced, so that the subject image incident through the imaging optical system is accurately connected to the light receiving surface of the imaging element. And a stable and good image can be obtained.

FIG. 2 is a perspective view showing an appearance of the front side of the imaging apparatus according to the first embodiment of the present invention. FIG. 2 is a perspective view showing the rear side appearance of the imaging apparatus according to the first embodiment of the present invention. The figure which shows the imaging device of the state which removed the cover and the connection cord. The longitudinal cross-sectional view which shows the imaging device of the state which removed the cover and the connection cord. The perspective view seen from the back side of an imaging device in the state where a cover and a connection cord were removed. The perspective view seen from the back side to which the board | substrate of a lens cell is joined. The figure which shows the indirect adhesion | attachment structure adhere | attached through the joining intermediate member. The figure which shows the filling adhesion | attachment structure filled with the adhesive agent and adhere | attached. The perspective view seen from the back side to which the board | substrate of the lens cell in a modification is joined. The perspective view seen from the back side to which the board | substrate of the lens cell in a comparative example is joined. (A), (b), (c) are states in which the rib portion is connected to the lens holding frame body in the imaging apparatus according to the second embodiment of the present invention in correspondence with the position of the lens that is greatly affected by the environmental temperature. FIG.

Hereinafter, the present invention will be described based on the illustrated embodiments.
<Embodiment 1>
FIG. 1 is a perspective view showing a front side appearance of an imaging apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a rear side appearance of the imaging apparatus. Note that the imaging apparatus of the present embodiment is an example applied to a back monitor camera used as a vehicle-mounted camera. The back monitor camera is installed, for example, in the vicinity of a license plate at the rear of the vehicle (automobile), and images a lower area on the rear side of the vehicle, and the captured image (moving image) is displayed on a monitor device installed in the vehicle interior. It is configured to be.

  As shown in these drawings, an imaging apparatus (back monitor camera) 1 according to the present embodiment includes an imaging lens system (imaging optical system) 10 and a lens cell 20 that holds the imaging lens system 10 on the inner peripheral surface side. A cover 30 containing a printed wiring board (hereinafter referred to as “substrate”) 40 on which an image sensor (solid-state imaging device) 41 described later is installed, and a wiring cord 50 are provided. In the imaging apparatus 1 of the present embodiment, the subject side is the front side and the substrate side (image sensor 41 side) is the back side along the optical axis direction of the imaging lens system 10.

  Screw holes 60 and 62 for screwing to the vehicle body and screw holes 64 and 66 for screwing the connection cord 50 to the cover 30 are formed on the back side of the imaging device 1 (connection cord 50 side). Yes. In the present embodiment, the outer surface of the lens cell 20 and the cover 30 constitute a housing (exterior) of the imaging device 1.

  FIG. 3 is a diagram illustrating the imaging device 1 with the cover 30 and the connection cord 50 removed, and FIG. 4 is a longitudinal sectional view thereof.

  As shown in these drawings, the lens cell 20 is integrally formed by resin molding, and the six first to sixth lenses 11 to 16 constituting the imaging lens system 10 are arranged on the inner side. A substrate 40 holding the image sensor 41 is bonded to the back side of the lens cell 20 (details of bonding between the lens cell 20 and the substrate 40 will be described later). The image sensor 41 is a solid-state imaging device using a CCD sensor or a CMOS sensor. The image sensor 41 photoelectrically converts a subject image formed by the imaging lens system 10, and a generated image signal is passed through a connection cord 50 in the vehicle interior. It is output to a monitor device (not shown) such as a navigation device.

  FIG. 5 is a view as seen from the back side of the imaging apparatus 1 with the cover 30 and the connection cord 50 removed. As shown in FIG. 4, the substrate 40 is formed in a substantially rectangular shape, and is formed in a concave shape at a corner portion at two opposite corners (instead of a substantially circular arc protruding in a convex shape). Defects 40a, 40b (arcs) are formed. In addition to the image sensor 41, electronic components such as capacitors and resistors are mounted on the substrate 40, but no electronic components are mounted in a predetermined region near the defect portions 40a and 40b.

  In addition, on the back surface portion of the lens cell 20, there are similarly formed defect portions 20a and 20b corresponding to the defect portions 40a and 40b on the substrate 40 side, and the defect portions 40a and 20a and the defect portions 40b and 20b are formed. The side cutouts formed respectively are used as spaces for the screws to pass through when the lens cell 20 and the cover 30 are connected by two screws (not shown).

  FIG. 6 is a perspective view of the lens cell 20 as viewed from the back side to which the substrate 40 is bonded, and the front side of the drawing is the back side (substrate 40 side) of the imaging device 1. As shown in FIG. 6, the rear side of the cylindrical lens holding frame portion (imaging lens system holding member) 21 that holds the imaging lens system (see FIG. 4) formed in the center of the lens cell 20 (FIG. 6). The proximal end side of the four rib portions 22a, 22b, 22c, and 22d extending in the radial direction is integrally connected to the outer peripheral surface on the front side. The rib portions 22a to 22d are formed at intervals of 90 degrees. Note that the front side (the back side in FIG. 6) of the lens holding frame portion 21 is integrally connected to the front side in the lens cell 20.

  The front end sides of the rib portions 22a to 22d are formed so as to be integrally connected to the inner wall surfaces of the four substrate fixing portions 23 formed so as to protrude from the vicinity of the inner wall surface of the lens cell 20 to the back side (substrate side). ing. The longitudinal direction of the lens holding frame portion 21 (the optical axis direction of the imaging lens system 10) of the rib portions 22a to 22d is the rear end portion of the lens holding frame portion 21 (on the side close to the image sensor 41 (substrate 40)). It is formed so as to be located from the end) to the vicinity of the center (near the fourth lens 14 of the imaging lens system 10). Therefore, the rib portions 22 a to 22 d are formed with a short length located near the center portion from the rear end portion of the lens holding frame portion 21.

  The first lens 11 (see FIG. 4) on the forefront side of the imaging lens system 10 is held on the back side of the lens holding frame portion 21 shown in FIG. 6, and the rearmost side of the imaging lens system 10 is on the front side. The sixth lens 16 (see FIG. 4) is held.

  The front side edge portion of the substrate 40 is bonded to the bonding end surface 23a formed at the tip portion of the four substrate bonding portions 23 with an adhesive. That is, the front side edge of the substrate 40 is bonded to the bonding end surface 23 a of each substrate bonding portion 23 by filling a thermosetting adhesive between each bonding end surface 23 a and the substrate 40.

  Furthermore, in this embodiment, as shown in FIG. 7, the concave joint side surface 24 formed on the outer wall surface of the two opposing substrate fixing portions 23 in the lens cell 20 and the vicinity of the front side edge portion of the substrate 40 are provided. The bonding is performed through the inverted L-shaped bonding intermediate member 25 to which the adhesive A is applied. As the adhesive A, for example, an ultraviolet curable adhesive can be suitably used. As shown in FIG. 5, the substrate 40 is bonded to the back surface side of the lens cell 20 by bonding between each bonding end face 23 a and the substrate 40 with these adhesives.

  As described above, in this embodiment, one side of the bonding intermediate member 25 is bonded to the bonding side surface 24 formed on the outer wall surface of the two substrate bonding portions 23 illustrated in FIG. 6 with the adhesive (ultraviolet curable adhesive). The other side of the joining intermediate member 25 is joined to the vicinity of the edge on the front side of the substrate 40 with an adhesive (ultraviolet curable adhesive). The joining intermediate member 25 is formed of a material that transmits ultraviolet rays.

  Further, a thermosetting adhesive is filled between the joining end surfaces 23a of the four substrate fixing portions 23 in the lens cell 20 and the front side edge portion of the substrate 40, and the joining surfaces of the two are fixed on the thermosetting adhesive. (The bonding region B between the bonding end surface 23a of the substrate fixing portion 23 and the front side edge of the substrate 40 shown in FIG. 8). Note that a thermosetting adhesive is used instead of an ultraviolet curable adhesive for bonding between the bonding end surface 23a of the substrate fixing portion 23 and the vicinity of the edge on the front side of the substrate 40. This is to obtain sufficient connection strength because it is located at a position where ultraviolet rays are harder to reach than the joining side surface 24. The reason why the adhesive is used without screwing or the like is to prevent an increase in size and weight.

  Further, in the rib portions 22a to 22d shown in FIG. 6, the length of the lens holding frame portion 21 in the longitudinal direction is short from the rear end portion of the lens holding frame portion 21 to the vicinity of the center portion. 9, the length of the rib portions 22a to 22d along the longitudinal direction of the lens holding frame portion 21 (the optical axis direction of the imaging lens system 10) is the rear end portion of the lens holding frame portion 21 (image sensor 41). You may form so that it may be located from the edge part of the side close | similar to (the board | substrate 40) to front part vicinity (2nd lens 12 vicinity of the imaging lens system 10). In this case, the rib portions 22a to 22d are formed with a long length located from the rear end portion of the lens holding frame portion 21 to the vicinity of the front portion side.

  Next, in the above-described embodiment, when the short-length rib portions 22a to 22d located from the rear end portion of the lens holding frame portion 21 shown in FIG. 6 to the vicinity of the center portion are connected, and as shown in FIG. Evaluation of deformation in the longitudinal direction of the lens holding frame portion 21 with respect to changes in environmental temperature when long rib portions 22a to 22d located from the rear end portion to the front portion side of the lens holding frame portion 21 are connected. did.

  As a comparative example, as shown in FIG. 10, the length along the longitudinal direction of the lens holding frame portion 21 of the rib portion 22 (the optical axis direction of the imaging lens system 10) is the front portion of the lens holding frame portion 21. A lens cell 20 formed so as to be located only near the side (near the second lens 12 of the photographing lens system 10) was prepared. Other configurations are the same as those of the above embodiment.

  Each part (lens cell, substrate, image sensor, first to sixth lenses (lenses 1 to 6) of the imaging lens system, the bonding intermediate member, and the adhesion of the imaging device (back monitor camera) 1 when this evaluation is performed. The material, Young's modulus, and linear expansion coefficient of the agent are as shown in Table 1 below. Note that the adhesive (indirect) in Table 1 is the adhesive and adhesive (filling) used when the bonding side surface 24 of the substrate fixing portion 23 and the substrate 40 are bonded via the bonding intermediate member 25. 23 is an adhesive for bonding the bonding side surface 24 of 23 and the substrate 40.

  The lens holding frame when the environmental temperature is changed (in this evaluation, when the temperature is increased from normal temperature (20 ° C.) to 80 ° C. and when the temperature is decreased from normal temperature (20 ° C.) to −30 ° C.) The evaluation results of deformation in the longitudinal direction of 21 are as shown in Table 2 below. In Table 2, the amount of deformation in the longitudinal direction of the lens holding frame portion 21 is expressed as the rear end portion of the lens holding frame portion 21 (the end portion on the side close to the image sensor 41 (substrate 40)) and the surface of the image sensor 41. It was shown as the distance fluctuation amount between. Further, in Table 2, the comparative example is the structure of the rib portion shown in FIG. 10, the rear end side rib portion is the structure of the rib portion shown in FIG. 6, and the long-area rib portion is the structure of the rib portion shown in FIG. It is.

  In the evaluation of Table 2, the lens holding frame when the environmental temperature is changed (when the temperature is increased from normal temperature (20 ° C.) to 80 ° C. and when the temperature is decreased from normal temperature (20 ° C.) to −30 ° C.). The total distance variation between the rear end portion of the portion 21 and the surface of the image sensor 41 is 20.2 (= | -10.1 | +10.1) μm in the structure of the rib portion of the comparative example of FIG. In the structure of the rib part (rear end side rib part) shown in FIG. 6, 19.8 (= | −9.9 | +9.9) μm, and in the structure of the rib part (longitudinal overall rib part) shown in FIG. 17.0 (= | −8.5 | +8.5) μm.

  As is apparent from the evaluation results in Table 2, the distance variation between the rear end portion of the lens holding frame portion 21 and the surface of the image sensor 41 when the environmental temperature is changed is shown in the comparative example of FIG. The rib structure shown in FIG. 6 (from the rear end portion of the lens holding frame portion) is compared to the rib portion structure (the rib portion is formed so as to be positioned only near the front side of the lens holding frame portion). In the case of the structure of the short-length rib portion located near the center portion), an improvement rate of 2 (= 19.8 / 20.2 × 100)% could be obtained.

  In addition, when the environmental temperature is changed, the distance fluctuation amount between the rear end portion of the lens holding frame portion 21 and the surface of the image sensor 41 is represented by the structure of the rib portion of the comparative example of FIG. 9 for the structure of the rib portion shown in FIG. 9 (a long length from the rear end portion of the lens holding frame portion to the vicinity of the front portion). In the rib portion structure), a significant improvement rate of 16 (= 17.0 / 20.2 × 100)% could be obtained.

  As described above, according to the imaging apparatus 1 of the present embodiment, in the case of FIG. 6, the rib portions 22a to 22d are formed so as to be located from the rear end portion of the lens holding frame portion 21 to the vicinity of the center portion. In the case of FIG. 9, the ribs 22 a to 22 d are formed so as to be positioned from the rear end portion of the lens holding frame portion 21 to the vicinity of the front portion side, so that the lens on the rear end portion side of the lens holding frame portion 21 is formed. The strength along the longitudinal direction of the holding frame portion 21 can be further increased.

  Therefore, even when the lens holding frame portion 21 is arranged at the rear portion of the vehicle body having a high environmental temperature, like the back monitor camera (imaging device 1) of the present embodiment, the lens holding frame portion 21 is deformed along the longitudinal direction. Can be reduced. For this reason, even when the environmental temperature changes, the subject image incident through the imaging lens system 10 held by the lens holding frame 21 in the lens cell 20 is accurately formed on the light receiving surface of the image sensor 41, A stable and good image can be obtained.

  Furthermore, in the imaging device 1 according to the present embodiment, the four rib portions 22a to 22d are provided at equal intervals between the outer peripheral surface of the lens holding frame portion 21 and the inner wall surface of the substrate fixing portion 23. Even when it changes, the lens holding frame portion 21 is not deformed biased, and the imaging lens system can always be held stably.

  In the above-described embodiment, an example of a back monitor camera has been described as an imaging device. In addition to this, for example, a vehicle-mounted camera such as a side monitor camera other than the back monitor camera, a digital still camera, a digital video camera, The present invention can be similarly applied to an imaging apparatus such as a camera-equipped mobile phone and a surveillance camera.

<Embodiment 2>
As shown in FIGS. 11A, 11 </ b> B, and 11 </ b> C, the imaging apparatus according to this embodiment includes a lens holding frame 74 that holds three lenses 71, 72, and 73 as an imaging lens system, Substrate fixing members 77a and 77b for fixing a substrate 76 having an image sensor (solid-state imaging device) 75 disposed on the front surface, and a rib portion for integrally connecting the outer surface of the lens holding frame 74 and the substrate fixing members 77a and 77b. 78a and 78b.

  In the present embodiment, at least one of the three lenses 71, 72, 73 is a plastic lens formed of a transparent resin material that is easily affected by the environmental temperature. When the imaging lens system is composed of a plurality of lenses, there are lenses that are easily affected by the environmental temperature due to lens characteristics and the like, and lenses that are less affected. This is determined by the optical design.

  Then, as in the imaging device shown in FIG. 11A, the configuration in which the central lens 72 among the three lenses 71, 72, 73 is more greatly affected by the environmental temperature than the other lenses 71, 73, The rib holding portions 74a and 78b of the lens holding frame 74 side are connected to correspond to the position of the central lens 72.

  In addition, as in the imaging device shown in FIG. 11B, the front lens 71 among the three lenses 71, 72, 73 is more affected by the environmental temperature than the other lenses 72, 73. The lens holding frame body 74 side of the rib portions 78a and 78b is connected in correspondence with the position of the lens 71 on the front surface side.

  Further, as in the imaging device shown in FIG. 11C, the rear lens 73 among the three lenses 71, 72, 73 is more affected by the environmental temperature than the other lenses 71, 72. The lens holding frame body 74 side of the rib portions 78a and 78b is connected in correspondence with the position of the lens 73 on the back side.

  As described above, the rib portions 78a and 78b are connected to the lens holding frame 74 in accordance with the position of the lens that is greatly affected by the environmental temperature, so that in the case of FIG. Even if a position variation occurs in the central lens 72 due to this, the position of the lens 72 is suppressed from the outside by connecting with the rib portions 78a and 78b corresponding to the position of the central lens 72 of the lens holding frame 74. Therefore, the position variation of the lens 72 can be reduced.

  In the case of FIG. 11B, even if the position of the lens 71 on the front side changes due to the influence of the environmental temperature, the rib portion 78a corresponds to the position of the lens 71 on the front side of the lens holding frame 74. , 78b to suppress the positional variation of the lens 72 from the outside, so that the positional variation of the lens 71 can be reduced. Further, in the case of FIG. 11C, even when the position of the rear lens 73 is changed due to the influence of the environmental temperature, the rib portion 78a corresponds to the position of the rear lens 73 of the lens holding frame 74. , 78b to suppress the positional variation of the lens 72 from the outside, so that the positional variation of the lens 73 can be reduced.

  In the above-described embodiment, the imaging lens system has three lenses. However, even when the number of lenses is two or four or more, a lens that is also greatly affected by the environmental temperature. The rib portion is connected to the lens holding frame in correspondence with the position.

  Moreover, in the said embodiment, although it was the structure which joins two rib parts to the outer surface of a lens holding frame, you may make it join three or more rib parts.

DESCRIPTION OF SYMBOLS 1 Back monitor camera 10 Imaging lens system 20 Lens cell 21 Lens holding frame part 22a, 22b, 22c, 22d Rib part 23 Board | substrate fixing | fixed part 30 Cover 40 Board | substrate 41 Image sensor

JP 2006-80667 A

Claims (6)

A housing that constitutes an exterior; an imaging lens system holding member that holds an imaging optical system in the housing; and a substrate on which an imaging element that photoelectrically converts a subject image formed by the imaging optical system is disposed on the front side; A substrate fixing member for fixing the substrate to the rear side of the imaging optical system holding member;
An imaging apparatus, wherein at least an outer surface of the imaging element side end portion of the imaging optical system holding member and an inner wall surface of the substrate fixing member are integrally connected by a rib portion.   2. The rib according to claim 1, wherein the rib portion is formed so as to be located from an end of the imaging optical system holding member to the vicinity of a center portion in a longitudinal direction of the imaging optical system holding member. The imaging device described.   The rib portion is formed so as to be positioned from the imaging element side end of the imaging optical system holding member to the vicinity of the end opposite to the imaging element along the longitudinal direction of the imaging optical system holding member. The imaging apparatus according to claim 1.   The substrate and the substrate fixing member are bonded to each other by an indirect bonding structure bonded via a bonding intermediate member and a filling bonding structure bonded and filled with an adhesive therebetween. The imaging device according to any one of claims 1 to 3.   5. The imaging apparatus according to claim 1, wherein a plurality of the rib portions are provided at a predetermined interval with respect to a circumferential direction of the imaging optical system holding member. An imaging optical system holding member that holds an imaging optical system composed of a plurality of lenses, a substrate on which an imaging element that photoelectrically converts a subject image formed by the imaging optical system is disposed on the front side, and the substrate are fixed An imaging device comprising a substrate fixing member that
A rib portion integrally connects the outer surface of the lens holding frame and the substrate fixing member so as to correspond to the position of the lens most affected by the environmental temperature among the plurality of lenses constituting the imaging optical system. An imaging device characterized by that.

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