JP2010199647A - Imaging module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a screwing part for fitting a front case, a rear case, and a bracket; and to suppress misalignment of an optical axis between a lens unit and an imaging element when the bracket is fitted to an automobile or the like by screwing, by maintaining the high strength of screwing. <P>SOLUTION: An imaging module 1 includes: the front case 3 mounted with the lens unit 2 on a subject side; the rear case 4 fitted to the front case 3; and the bracket 5 fitted to the rear case 4. The front case 3 has a first screwing through hole 3a formed, the rear case 4 has a second screwing through hole 4a formed, and the bracket 5 has a third screwing through hole 5a formed. The rear case 4 is fitted to the front case 3 with a first screw 10 by screwing into the first and second screwing through holes 3a and 4a from the subject side, and the bracket 5 is fitted to the rear case 4 with a second screw 11 by screwing into the second and third screwing through holes 4a and 5a from the side opposite to the subject side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging module using an imaging device composed of a semiconductor image sensor such as a CCD image sensor.

  A conventional imaging module having a bracket for mounting to an automobile or the like has the following configuration, for example.

  A front case in which the lens unit is mounted on the subject side, and an imaging board on which the image sensor is mounted is installed on the opposite side of the subject side with the image sensor facing the lens unit, and attached to the front case The rear case that seals the imaging substrate in the space inside the front case and the bracket that is attached to the rear case.

  In the conventional imaging module having such a configuration, the front case and the rear case are attached by screwing with a first screw, and the rear case and the bracket are attached by screwing with a second screw. The first screw and the second screw are respectively screwed into separate screwing portions.

Japanese Utility Model Publication No. 6-72856

  In the conventional imaging module, the front case and the rear case are screwed and attached with a first screw, and the rear case and the bracket are screwed into a screwing portion separate from the first screw. Since it is fixed by screwing with a screw, it has a two-stage screwing structure. As a result, there is a problem that the screwing portion becomes large and the imaging module itself becomes large.

  Further, if the screw diameter is reduced in order to reduce the size of the screwing portion, the strength of screwing is insufficient. Then, when the bracket is attached to an automobile or the like by screwing, the optical axis length between the lens unit and the image sensor changes due to the stress on the case after the screwing applied to the bracket, or the optical axis is There is a problem that the image quality is liable to be deteriorated.

  Accordingly, the present invention has been devised in view of the above-described conventional problems, and its purpose is to downsize the screwing portion for attaching the front case, the rear case, and the bracket, and downsize the imaging module itself. It is to be. In addition, it retains high screwing strength and prevents the optical axis length between the lens unit and the image sensor from changing or shifting when the bracket is attached to an automobile or the like by screwing. It is to be able to obtain a high-quality image.

  In the imaging module of the present invention, the lens unit is mounted on the subject side, and an imaging board on which the imaging element is mounted is installed in a portion opposite to the subject side with the imaging element facing the lens unit. A front case, a rear case attached to the front case and sealing the imaging board in an inner space with the front case, and an external mounting bracket attached to the rear case. The front case has a first screwing through hole, the rear case has a second screwing through hole, and the bracket has a third screwing through hole, and the front case has the rear screw hole. A case is attached to the first and second screwing through holes by a first screw screwed from the object side, and the bracket is attached to the rear case. And it is characterized in that it is attached by the second and third screw fastening through the second screw the screwed from the subject side and the side opposite to the hole.

  The imaging module of the present invention is characterized in that, in the above configuration, the first screw is screwed so as to exist inside an opening on the subject side of the first screwing through hole. It is what.

  The imaging module of the present invention is characterized in that, in the above configuration, the rotational direction of the screwing of the first screw and the rotational direction of the screwing of the second screw are opposite to each other. .

  According to the image pickup module of the present invention, the lens unit is mounted on the subject side, and the image pickup board on which the image pickup device is mounted is installed in a portion opposite to the subject side with the image pickup element facing the lens unit. The front case includes a front case, a rear case attached to the front case and sealing the imaging board in an inner space with the front case, and an external mounting bracket attached to the rear case. The first screw-through hole is formed with the second screw-through hole in the rear case, and the third screw-through hole is formed in the bracket. The rear case is formed in the front case, and the first and second holes are formed in the front case. It is attached to the screwing through hole by the first screw screwed from the subject side, and the bracket is attached to the rear case, and the second and third screwing through holes from the opposite side to the subject side. Since it is attached by the second screw screwed in, the first screw and the second screw can be coaxially arranged, and the screw fixing portion for attaching the front case, the rear case and the bracket is greatly increased. Thus, the imaging module itself can be reduced in size.

  In the imaging module of the present invention, in the above configuration, when the first screw is screwed so as to exist inside the opening on the subject side of the first screwing through hole, the screwing portion is Thus, the rear case and the bracket are positioned more preferentially than the front case, so that the rear case and the bracket can be more firmly attached. As a result, it is possible to reduce the influence of the stress on the case after the screwing applied to the bracket attached to the external automobile by screwing. Accordingly, it is possible to obtain a high-quality image while suppressing the change of the optical axis length between the lens unit and the image pickup device or the deviation of the optical axis.

  In addition, since the first screw does not protrude from the first screwing through hole, when the lens closest to the subject (frontmost side) of the lens unit has a surface protruding outside such as a wide-angle lens, the first screw It is possible to prevent the 1 screw from being reflected on the frontmost lens.

  Furthermore, since the first screw does not protrude from the first screwing through hole, the aesthetic appearance when the imaging module is viewed from the subject side is not impaired.

  In the imaging module of the present invention, in the above configuration, when the rotation direction of the first screw and the rotation direction of the second screw are opposite to each other, the distortion caused by the stress due to the screwing cancels each other. By acting so as to match, the front case, the rear case, and the bracket can be prevented from being deformed by distortion. Accordingly, it is possible to further suppress the change in the optical axis length between the lens unit and the image sensor or the deviation of the optical axis.

1 is a perspective view of a basic configuration showing an example of an embodiment of an imaging module of the present invention. It is a longitudinal cross-sectional view in the AA line of the imaging module of FIG. FIG. 3 is a longitudinal sectional view similar to FIG. 2, and is a longitudinal sectional view showing a positional relationship between a lens unit and a first screw.

  Hereinafter, embodiments of an imaging module of the present invention will be described in detail with reference to the drawings.

  1 and 2 show an example of an embodiment of an imaging module according to the present invention. FIG. 1 is a perspective view of a basic configuration of the imaging module, and FIG. 2 is a longitudinal sectional view taken along line AA in FIG.

  In the imaging module 1 of the present embodiment, the lens unit 2 is mounted on the subject side, and the imaging substrate 8 on which the imaging element 7 is mounted is opposite to the subject side with the imaging element 7 facing the lens unit 2. A front case 3 installed at the site, a rear case 4 attached to the front case 3 and sealing the imaging substrate 8 in an inner space of the front case 3, and an external attachment attached to the rear case 4 The first case is provided with a first screwing through hole 3a, the rear case 4 is provided with a second screwing through hole 4a, and the bracket 5 is provided with a third screwing through hole 5a. The rear case 4 is attached to the front case 3 by the first screw 10 screwed into the first and second screwing through holes 3a, 4a from the object side, and the rear case 4 is formed. To bra Tsu bets 5 is attached by a second screw 11 screwed from the opposite side to the object side in the second and third screw fastening through-holes 4a, 5a.

  With the above configuration, the first screw 10 and the second screw 11 can be coaxially arranged, and the screwing portion for attaching the front case 3, the rear case 4 and the bracket 5 can be greatly reduced in size and imaged. The module 1 itself can also be reduced in size.

  The first screw 10 and the second screw 11 are arranged coaxially, but need not be arranged completely coaxially, and the axis of the first screw 10 and the axis of the second screw 11 are slightly different. It may be shifted. For example, the axis of the first screw 10 and the axis of the second screw 11 may be deviated by about 2 mm or less, and the above-described effects can be achieved by setting this range.

  Further, it is preferable that there are a plurality of sets of the first screw 10 and the second screw 11. In this case, when attaching the front case 3, the rear case 4, and the bracket 5, the optical axis length between the lens unit 2 and the image sensor 7 can be changed and the optical axis can be prevented from shifting. it can.

  Further, when there are a plurality of sets of the first screw 10 and the second screw 11, when comparing adjacent sets, the rotation direction of one set of screws and the rotation direction of the other set of screws are opposite to each other. The direction should be good. In this case, it is possible to suppress the deformation of the front case 3, the rear case 4, and the bracket 5 due to the distortion by canceling out the distortion caused by the stress due to the screwing.

  Note that the first screw-through hole 3a has the front case 3 because the first screw 10 is screwed from the subject side of the front case 3 and further screwed into the second screw-through hole 4a of the rear case. Are formed as through holes. Since the first screw 10 is screwed from the subject side of the rear case 4 and the second screw 11 is screwed from the opposite side of the rear case 4 to the subject side, the second screwing through hole 4a 4 is formed as a through hole. Since the second screw 11 is screwed from the opposite side to the subject side of the bracket 5 and further screwed into the second screwing through hole 4a of the rear case 4, the third screwing through hole 5a Are formed as through holes.

  Such an imaging module 1 is used for in-vehicle use, for example, and has a function of imaging a white line on a road or imaging a blind spot of a driver who drives a vehicle, and controlling an automobile (ECU) The operation is controlled by an electronic control unit). The electrical signal output from the imaging module 1 is converted into an image signal by the ECU, and displayed on a display installed in front of the driver's seat, for example.

  The imaging element 7 is a semiconductor image sensor element such as a CCD image sensor or a CMOS image sensor.

  The lens unit 2 has a function of condensing light from the subject on the image sensor 7. For example, a first lens having a convex shape on the front side in order to collect light at a wide angle, The lens group is composed of a second lens and a third lens for bringing light that has passed through the lens closer to parallel as light rays. When the lens unit 2 is composed of the above-described three lenses, for example, the optical axis in the order of the first lens, the second lens, and the third lens from the front side (the subject side and the upper side in FIG. 2). Arranged to overlap in the direction. The lens unit 2 may have four or more lenses.

  The case attaches and supports the lens unit 2 located on the front side. The case is divided into a front case 3 and a rear case 4, and these are integrally attached. For example, the front case 3 is disposed on the front surface side, and is disposed on the rear surface side of the retainer 12 and an annular retainer 12 as a pressing member that presses the first lens of the lens unit 2 to the rear surface side (opposite the subject side). And a generally cylindrical lens barrel 6 as a lens holder. The second lens and the third lens are fixed to the lens barrel 6 of the front case 3, and the first lens is fixed so as to be pressed against the lens barrel 6 by the retainer 12.

  The retainer 12 and the lens barrel 6 are produced, for example, by the method described below.

  The lens barrel 6 is prepared by preparing a mold for injection molding having a cavity provided in accordance with the shape of the lens barrel 6, and pouring the raw material for the lens barrel 6 into the cavity and solidifying it. It can be manufactured using an injection molding method in which a predetermined shape is formed by molding. Similarly, the retainer 12 is prepared by preparing a mold for injection molding having a cavity formed in a shape that matches the shape of the retainer 12, and pouring the raw material for the retainer 12 into the cavity and solidifying it. It can be formed into a predetermined shape by molding. Such a retainer 12 and the lens barrel 6 are made of an insulating resin such as polycarbonate (PC) or polyphthalamide (PPA), for example, to reduce the weight. Usually, in order to match the thermal expansion and thermal contraction of the retainer 12 and the lens barrel 6, it is preferable to use the same material for both.

  An imaging substrate 8 is attached to the back side of the imaging module 1. An imaging element 7 housed in a package made of ceramics, resin, or the like is installed on the main surface on the front side of the imaging substrate 8.

  The image pickup device 7 is attached to the case by mounting the image pickup device 7 on the main surface on the front side of the image pickup substrate 8 and attaching the image pickup substrate 8 to the front case 3 via the connection terminals 9 and solder. .

  The imaging substrate 8 is configured by a printed wiring board formed by, for example, impregnating a glass cloth with an epoxy resin, or by adding a glass filler to an epoxy resin. On the surface or inside of the image pickup substrate 8, an electrical connection with terminals such as other components different from the image pickup element 7 to be mounted, or a wiring conductor for fixing them and a ground wiring for grounding are formed. For such wiring conductors and ground wirings, a method of forming a conductive metal such as copper or gold by a plating method, a method of bonding a metal foil previously formed in a wiring pattern shape, or a metal foil is deposited on the entire surface It is formed on the surface of the printed wiring board or inside by using a method of etching away unnecessary portions from the substrate by etching.

  Such an imaging substrate 8 is prepared, for example, by preparing a copper-clad substrate with a copper foil deposited on the entire front and back surfaces of a commercially available product, cutting the copper-clad substrate to a desired size, and diluting the copper foil deposited on the surface with dilute hydrochloric acid. It is manufactured by etching a desired wiring pattern with an acidic solution such as. In addition, if necessary, a through hole is formed using a laser beam or a drill, and the through conductor is embedded by filling the through hole with a metal paste to electrically connect the wiring patterns on the front and back of the board. Is also possible.

  An IC (not shown) that processes an electrical signal from the imaging element 7 and a cable (not shown) that electrically connects the wiring conductor of the imaging board 8 and the ECU are provided on the main surface on the back side of the imaging board 8. ) May be mounted such as a connector (not shown).

  The rear case 4 can be manufactured using an injection molding method in the same manner as the front case 3. That is, an injection mold having a cavity provided in accordance with the shape of the rear case 4 is prepared, and the raw material for the rear case 4 is poured into the cavity to be solidified and molded. Form into shape.

  The front case 3 and the rear case 4 may be made of a metal such as stainless steel, aluminum, brass (copper-zinc alloy). In this case, heat generated in the imaging module can be efficiently radiated from the front case 3 and the rear case 4 to the outside through the first and second screws 10 and 11.

  The bracket 5 is a plate-like overhanging portion for attaching the imaging module 1 to an external machine or device such as an automobile, and has a through hole 5a for attaching to the external machine or device by screwing or the like. ing. The shape of the bracket 5 is not limited to a plate shape, and may be a shape having a side wall portion that protects the case, for example, a plate shape, a box shape, or the like. The bracket 5 is made of a resin such as polycarbonate (PC) or polyphthalamide (PPA), a metal such as stainless steel, copper, or aluminum.

  In the imaging module 1 of the present embodiment, it is preferable that the rear case 4 accommodates the imaging substrate 8 in which the imaging element 7 is positioned with respect to the lens unit 2 inside. In this case, the positioned imaging substrate 8 can be protected by the rear case 4, and the case made up of the front case 3 and the rear case 4 can be downsized. Further, the inner space of the case is only the inner side of the rear case 4, and the inner space of the case can be reduced.

  Further, in the imaging module 1 of the present embodiment, it is preferable that the first screw 10 is screwed so as to exist inside the subject-side opening of the first screwing through hole 3a.

  With the above configuration, the screwing portion is positioned more on the side of the rear case 4 and the bracket 5 than the front case 3, and the rear case 4 and the bracket 5 can be attached more firmly. As a result, it is possible to reduce the influence on the case 4 after the stress due to screwing applied to the bracket 5 attached to the external automobile or the like by screwing. Therefore, it is possible to obtain a high-quality image while suppressing the change of the optical axis length between the lens unit 2 and the image sensor 7 or the deviation of the optical axis.

  Further, since the first screw 10 does not protrude from the first screwing through-hole 3a, the lens on the most object side (frontmost side) of the lens unit 2 has a surface protruding outside such as a wide-angle lens. In addition, it is possible to prevent the first screw 10 from being reflected on the front lens.

  Further, since the first screw 10 does not protrude from the first screwing through hole 3a, the aesthetic appearance when the imaging module 1 is viewed from the subject side is not impaired.

  In this case, as shown in FIG. 3, the first screw 10 has a distal end (upper end of the head) on the rear side of the center Ox of the central axis x parallel to the optical axis direction of the lens unit 2 ( More preferably, it is on the opposite side of the subject.

  With the above configuration, the influence of distortion on the lens unit 2 due to screwing of the first screw 10 is further reduced, and the optical axis length between the lens unit 2 and the image sensor 7 is changed or the optical axis is shifted. It is possible to obtain a higher-quality image while suppressing the above.

  In the imaging module of the present embodiment, it is preferable that the rotation direction of the first screw 10 and the rotation direction of the second screw 11 are opposite to each other.

  With the above-described configuration, the distortion caused by the stress due to screwing acts so as to cancel each other, and deformation of the front case 3, the rear case 4, and the bracket 5 due to the distortion can be suppressed. Accordingly, it is possible to further suppress the change in the optical axis length between the lens unit 2 and the image sensor 7 or the deviation of the optical axis.

  The first screw 10 and the second screw 11 may be self-tapping screws. In this case, the front case 3 and the rear case 4 can be made of a material that can be self-tapped (threaded with a screw) such as resin, and the front case 3 and the rear case 4 can be molded at low cost. It can be made of a lightweight material.

  An embodiment of the imaging module of the present invention will be described below.

  The imaging module of this example having the configuration shown in FIGS. 1 and 2 was produced as follows. First, a rectangular cylindrical front case 3 made of polycarbonate formed by an injection molding method and a square box-shaped rear case 4 made of polycarbonate were prepared. The front case 3 has a square cross section of 23 mm in length and 23 mm in width and a height of 10 mm. The rear case 4 has a square cross section of 23 mm in length and 23 mm in width. And having a height of 7 mm. The front case 3 has a cylindrical lens barrel 6 inside.

  Next, the lens unit 2 composed of three lenses was attached to the lens barrel 6 inside the front case 3, and the lens unit 2 was fixed by an annular retainer 12. Further, the connection terminal 9 provided in the lens barrel 6 inside the front case 3 is inserted into the through hole of the image pickup substrate 8 in which the image pickup element 7 is installed on the main surface on the subject side, and around the through hole. The imaging substrate 8 was attached to the front case 4 by joining the connection terminals 9 to the electrode pads via solder.

  Next, the front case 3 and the rear case 4 are attached by the first screwing through hole 3a and the first screw 10 screwed into the second screwing through hole 4a. Were attached by a second screw 11 screwed into the second screwing through hole 4a and the third screwing through hole 5a. As a result, the imaging substrate 8 was sealed in the inner space constituted by the front case 3 and the rear case 4.

  At this time, as shown in FIG. 3, the first screw 10 has a tip on the subject side (upper end of the head) behind the center Ox of the center axis x parallel to the optical axis direction of the lens unit 2 (subject (The side opposite to the side).

  The first screw 10 and the second screw 11 had a main body diameter of 1.4 mm, a head diameter of 2 mm, and a length of 5 mm.

  On the other hand, as a comparative example, the front case and the rear case were screwed and attached with a first screw, and the rear case and the bracket were screwed into a screwing portion separate from the first screw. An imaging module attached with a second screw was prepared. In this imaging module, the front case has a square cross section of 25 mm in length and 25 mm in width and a height of 12 mm. The rear case 4 has a square cross section of 25 mm in length and 25 mm in width. The height was 19 mm.

  When the size of the imaging module 1 of the example and the imaging module of the comparative example were compared in volume ratio, the imaging module 1 of the example was about 0.46 times the imaging module of the comparative example and was significantly downsized. became.

  In the imaging module 1 of the embodiment, the first screw 10 is screwed in such that it exists inside the opening on the subject side of the first screwing through hole 3a. Since the rear case 4 and the bracket 5 are positioned more preferentially than the front case 3, the rear case 4 and the bracket 5 can be more firmly attached. As a result, it is possible to reduce the influence on the case 4 after the stress caused by screwing applied to the bracket 5 attached to the external automobile or the like by screwing, and the optical axis length between the lens unit 2 and the image sensor 7 can be reduced. It was possible to obtain a high-quality image while suppressing changes and deviation of the optical axis.

  The present invention is not limited to the above-described embodiment and examples, and various modifications may be made without departing from the scope of the present invention.

1: imaging module 2: lens unit 3: front case 3a: first screwing through hole 4: rear case 4a: second screwing through hole 5: bracket 5a: third screwing through hole 7: imaging element 8: Imaging board
10: First screw
11: Second screw

Claims (3)

  A front case in which a lens unit is mounted on a subject side, and an imaging board on which an imaging element is mounted is disposed on a portion opposite to the subject side with the imaging unit facing the lens unit; and the front case And a rear case that seals the imaging substrate in an inner space with the front case, and an external mounting bracket that is attached to the rear case. A second screwing through hole is formed in the rear case, and a third screwing through hole is formed in the bracket. The rear case is formed in the front case, and the first and second screwing through holes are formed in the bracket. The bracket is attached to the rear case by the first screw screwed into the second screwing through hole from the subject side, and the second and third screwing Imaging module, characterized in that attached by a second screw screwed from said object side to the through hole opposite.   2. The imaging module according to claim 1, wherein the first screw is screwed so as to exist inside an opening on the subject side of the first screwing through hole.   The imaging module according to claim 1, wherein a rotation direction of the first screw and a rotation direction of the second screw are opposite to each other.

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