JP2022113407A - Imaging module - Google Patents

Abstract

To provide an imaging module that can improve an electromagnetic wave shielding function of a lens unit.SOLUTION: An imaging module according to the present disclosure comprises a conductive housing provided with an image pickup device and a cylindrical lens barrel attached to the housing. The lens barrel includes therein a plurality of lenses that are arranged along an optical axis, a metal plate that is provided between lenses of the plurality of lenses while in contact with an inner wall of the lens barrel and has an opening in a surface intersecting with the optical axis, and a connection unit that electrically connects the metal plate and the housing to each other. The diameter of the opening in the metal plate has a size according to the diameter of a beam of light condensed by the lens located on a front stage of the metal plate, in an optical path on which light entering the inside of the lens barrel reaches the image pickup device.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to imaging modules.

In recent years, with the popularization of vehicle driving support systems, vehicles are increasingly equipped with perimeter monitoring systems using in-vehicle cameras and mirror replacement systems using in-vehicle cameras. Imaging modules used for these applications are often made by combining a lens unit for forming an image of a subject and a case containing an imaging device that converts the formed image into a video signal. be done. The lens unit has a plurality of lenses made of glass or plastic and an aperture that adjusts the amount of light entering the lens barrel and reaching the imaging device. The imaging element is mounted on the sensor substrate together with peripheral circuits and fixed to the case.

By the way, in general, an imaging module mounted on a vehicle is surrounded by electronic devices and the like. In such a case, if electromagnetic waves radiated from electronic devices around the imaging module enter the inside of the imaging module, the imaging element will be affected by the electromagnetic waves, and the video signal converted by the imaging element will be disturbed. We may not be able to provide the high-confidence images needed for assistance.

Therefore, metal has been used as the material of the case, or a structure in which a metal shield structure is arranged in the case has been adopted. With these configurations, it is possible to give the case a certain level of electromagnetic shielding function, but on the other hand, it is not possible to block the electromagnetic waves that enter the image sensor from the lens unit, so the electromagnetic shielding of the lens unit is insufficient. be.

Therefore, it is conceivable to give the lens unit an electromagnetic shielding function by using metal as the material of the lens barrel. However, increasing the number of metal parts increases the cost, and when the image pickup module is mounted outside the vehicle, corrosion occurs due to acid rain or the like, leading to deterioration.

Conventionally, in order to reduce the electromagnetic waves incident on the image pickup device from the opening of the lens unit without using metal as the material of the lens barrel, a conductive member connected to GND is placed inside the lens unit or between the lens unit and the image pickup device. A technique has been proposed to provide between For example, in Patent Literatures 1 and 2, among a plurality of lenses provided in a lens unit, the image sensor side of the lens closest to the subject and the image sensor side of the lens closest to the image sensor are connected to the GND. Techniques for placing a sexual member are disclosed. Further, for example, Patent Document 3 discloses a technique of arranging a conductive member connected to GND between a lens unit and an imaging device.

JP 2013-109188 A JP 2019-050516 A WO2018/221210

However, the conventional techniques described above still have the following problems. Specifically, in the conventional technology, an opening is provided in the conductive member for passing the light that enters the lens barrel and reaches the imaging device. It has not been. If the opening of the shield member becomes large, the electromagnetic shielding function of the lens unit deteriorates, and as a result, it may not be possible to provide highly reliable images necessary for driving assistance.

The present disclosure has been made in view of the above problems, and a main object thereof is to provide an imaging module capable of improving the electromagnetic shielding function of the lens unit.

An image pickup module comprising a conductive housing having an image sensor and a cylindrical lens barrel attached to the housing, wherein the lens barrel is arranged inside along an optical axis. a lens, a metal plate provided in a space between the lenses while being in contact with the inner wall of the lens barrel and having an opening on a plane where the optical axes intersect, the metal plate and the housing. and a connection portion for electrically connecting the metal plate, wherein the diameter of the opening of the metal plate is located in front of the metal plate in the optical path along which the light entering the lens barrel reaches the image pickup device. It has a size corresponding to the diameter of the beam condensed by the lens.

The imaging module according to the present disclosure can improve the electromagnetic shielding function of the lens unit.

FIG. 1 is a schematic vertical cross-sectional view of an imaging module according to the first embodiment. FIG. 2 is a perspective view of a diaphragm and legs according to the first embodiment. FIG. 3 is a schematic cross-sectional view of the lens barrel at position AA in FIG. FIG. 4 is a perspective view of a connecting portion according to the first embodiment. FIG. 5 is a schematic vertical cross-sectional view of an imaging module according to the second embodiment. FIG. 6 is a perspective view of a diaphragm and legs according to the second embodiment.

An imaging module according to the present disclosure will be described below with reference to the drawings.

(First embodiment)
The configuration of the imaging module 10 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG.

FIG. 1 is a schematic vertical cross-sectional view of an imaging module 10 according to the first embodiment. As shown in FIG. 1, the imaging module 10 includes a lens unit 20 for forming an image of a subject, and a camera unit 30 for converting the formed image into a video signal.

The lens unit 20 has a lens barrel 21 , a diaphragm 22 and a lens 23 .

The lens barrel 21 is a cylindrical member with both ends opened. Inside the lens barrel 21, a diaphragm 22 and a lens 23 are arranged at predetermined positions. The lens barrel 21 can be formed using, for example, a resin material.

A flange-like adhesive flange 25 is provided on the outside of the lens barrel 21 . The lens unit 20 (lens barrel 21 ) is attached to the camera unit 30 with an adhesive or the like via an adhesive flange 25 . Note that the method of attaching the lens barrel 21 to the camera unit 30 is not limited to the adhesive.

The lens 23 is made of plastic, glass, or the like. It is arranged along the optical axis inside the lens barrel 21, and forms an image of light from a subject on an imaging device 31, which will be described later. Although FIG. 1 shows an example in which three lenses 23 (23a, 23b, and 23c) are provided, the number of lenses 23 is not limited to this, and may be two or four or more.

The diaphragm 22 is arranged between the lenses 23 while being in contact with the inner wall of the lens barrel 21 . FIG. 1 shows an example in which a diaphragm 22 is provided between the lens 23a and the lens 23b. In other words, in FIG. 1, the diaphragm 22 is arranged after the lens 23a positioned at the head of the light entering direction in the optical path (light entering direction) along which the light entering the inside of the lens barrel 21 reaches the imaging device 31. shows an example. Note that the position where the diaphragm 22 is arranged is not limited to the example in FIG. 1, and may be behind the lens 23b.

The diaphragm 22 has an opening 221 (see FIG. 2), which will be described later, and adjusts the amount of light that passes through the lens 23, thereby adjusting the amount of light received by the imaging device 31 or the subsequent lens 23. As the material of the diaphragm 22, for example, metal such as stainless steel can be used. A black film is formed on the surface of the diaphragm 22 .

Further, the diaphragm 22 is provided with a leg portion 24 . The leg portion 24 is a strip-shaped conductive member extending from the edge of the diaphragm 22 toward the camera unit 30 and is provided integrally with the diaphragm 22 . The leg portion 24 abuts on the connecting portion 32 . The leg portion 24 functions together with the connecting portion 32 as a connecting portion for electrically connecting the diaphragm 22 to the case 34 . The leg portion 24 is made of metal, similar to the diaphragm 22 . The diaphragm 22 and the leg portion 24 function as a shield member 40 together with a connection portion 32 which will be described later. The configuration and function of the shield member 40 will be described later.

The camera unit 30 includes an imaging device 31 , a connection portion 32 , screws 33 , a case 34 and a sensor substrate 35 . The camera unit 30 also includes an output mechanism (not shown) that outputs a signal output from the imaging element 31 to the outside as image data.

The imaging element 31 is, for example, a CMOS (Complementary MOS) or a CCD (Charge Coupled Device), receives light that has passed through a lens 23 in the barrel 21, and converts it into a video signal.

The sensor substrate 35 is a substrate on which the imaging device 31 is mounted. A hole (screw hole) through which a screw (screw 33) is passed is formed in the edge of the sensor substrate 35 . The sensor board 35 is fixed to the case 34 with screws 33 through the screw holes.

The connecting portion 32 is provided on the surface of the sensor substrate 35 on which the imaging element 31 is mounted. The connecting portion 32 is provided so as to cover the surface of the sensor substrate 35 on which the imaging device 31 is mounted, and has an opening 321 (see FIG. 4), which will be described later, at a position facing the imaging device 31 . An end portion of the connection portion 32 is sandwiched between the case 34 and the sensor substrate 35 and fixed to the case 34 together with the sensor substrate 35 by screws 33 . Also, the connecting portion 32 is in contact with the leg portion 24 extending from the diaphragm 22 .

The screws 33 are screwed into the screw holes of the sensor substrate 35 to fix the connecting portion 32 and the sensor substrate 35 to the case 34 . As the material of the screws 33, for example, metal such as stainless steel can be used. The connecting portion 32 and the sensor substrate 35 are electrically connected to the case 34 by being fixed by the screws 33 .

The case 34 contains the imaging device 31 , the connection portion 32 , the screws 33 and the sensor substrate 35 . The case 34 is fixed to the lens unit 20 with an adhesive while the relative positional relationship between the imaging element 31 and the lens unit 20 is adjusted. As a material for the case 34, for example, metal such as aluminum can be used. A black film is formed on the surface of the case 34 .

Next, the configuration and function of the shield member 40 will be described with reference to FIGS. 2, 3 and 4 in addition to FIG.

The shield member 40 is composed of the aperture 22 , the legs 24 and the connecting portion 32 .

FIG. 2 is a perspective view of the diaphragm 22 and the legs 24 according to the first embodiment. The diaphragm 22 has an opening 221 on a plane that intersects the optical axis of the lens 23 . The diameter of the aperture 221 of the diaphragm 22 is less than the inner diameter of the lens barrel 21 . More specifically, the diameter of the opening 221 of the diaphragm 22 is determined by the lens 23 (23a) located in front of the diaphragm 22 in the optical path along which the light entering the lens barrel 21 reaches the imaging element 31. It has a size corresponding to the luminous flux diameter. For example, the diameter of the aperture 221 of the diaphragm 22 is set to be substantially equal to or less than the beam diameter condensed by the preceding lens 23 at the arrangement position where the diaphragm 22 is provided. The diameter of the opening 221 of the diaphragm 22 is preferably adjusted according to the positional relationship with the lens 23 positioned before or after the arrangement position of the diaphragm 22 .

The diaphragm 22 adjusts the amount of light that passes through the lens 23 via the opening 221, thereby adjusting the amount of light received by the imaging element 31 or the lens 23 in the subsequent stage. That is, since the aperture 22 has an opening 221 smaller than the inner diameter of the lens barrel 21, the electromagnetic waves entering the lens barrel 21 from the opening of the lens unit 20 can be reduced. These structures can reduce electromagnetic waves entering the imaging device 31 through the opening of the lens unit 20 .

One or more legs 24 are provided at the edge of the aperture 22 . FIG. 2 shows an example in which two legs 24 extend from the aperture 22 . The leg portion 24 abuts on the connecting portion 32 by extending along the inner wall of the lens barrel 21 to the connecting portion 32 . More specifically, grooves 27 for fixing the legs 24 are provided in the inner wall of the lens barrel 21 (see FIG. 3).

FIG. 3 is a schematic cross-sectional view of the lens barrel 21 at position AA in FIG. As shown in FIG. 3, the inner wall of the lens barrel 21 is provided with a concave groove 27 . Also, the lens 23 (23b) is held by a convex portion excluding the groove 27 on the inner wall of the lens barrel 21. As shown in FIG. That is, groove 27 forms a gap between the inner wall of lens barrel 21 and lens 23 .

One or a plurality of grooves 27 are provided linearly in the direction of the imaging device 31 from the installation position of the diaphragm 22 . The example of FIG. 3 shows an example in which eight grooves 27 are provided at regular intervals. It is preferable that the number and positions of the grooves 27 correspond to the number and positions of the legs 24 extending from the diaphragm 22 . For example, in the configuration example of the diaphragm 22 and the leg portion 24 shown in FIG. 2, a pair of grooves 27 may be provided on the inner wall of the lens barrel 21 at positions facing each other. Moreover, it is preferable to design the width and depth of the groove 27 according to the width and thickness of the leg portion 24 .

The leg portion 24 extends to the connection portion 32 while being fitted in the groove 27 described above. That is, the leg portion 24 is fixed in position within the lens barrel 21 by fitting into the gap between the inner wall of the lens barrel 21 and the lens 23 . In this way, the structure in the lens barrel 21 is such that the leg portion 24 does not interfere with other components (the lens 23). Further, by extending the leg portion 24 along the lens barrel 21, it is possible to reduce the electromagnetic waves incident on the inner side of the lens barrel 21 from the side surface of the lens barrel 21. FIG.

FIG. 4 is a perspective view of the connecting portion 32 according to the first embodiment. The connecting portion 32 has a convex shape protruding toward the lens 23 and is formed so as to cover the sensor substrate 35 . Also, the connecting portion 32 has an opening 321 on a surface that intersects the optical axis of the lens 23 . The opening 321 of the connecting portion 32 is provided at a position facing the imaging element 31 of the sensor substrate 35 in the subsequent stage. As a material of the connecting portion 32, for example, a metal such as aluminum can be used. Note that the diameter of the opening 321 may be any size that does not interfere with the light received by the imaging element 31 . Therefore, it is preferable that the diameter of the aperture 321 is equal to or larger than the diameter of the aperture 221 of the diaphragm 22 or larger than the imaging element 31 .

In the configuration described above, the leg portion 24 extending from the diaphragm 22 is brought into contact with the connection portion 32 , and the connection portion 32 is connected to the case 34 by the screw 33 . As a result, the diaphragm 22, the leg portion 24, and the connection portion 32 are electrically connected to the case 34, so that they have substantially the same potential as the case 34, that is, substantially the same potential as the GND potential of the sensor substrate 35 (image pickup device 31). It's becoming

With these configurations, the shield member 40 composed of the diaphragm 22 , the leg portion 24 and the connection portion 32 can improve the electromagnetic shielding characteristics of the imaging module 10 .

Furthermore, by using the diaphragm 22 as the shield member 40, it is possible to improve the electromagnetic shielding characteristics of the imaging module 10 without adding a new member.

(Second embodiment)
An imaging module 10b according to the second embodiment will be described with reference to FIG. In the second embodiment, the connecting portion 32b is connected to the case 34 through a through hole 26b formed in the lens barrel 21b. Note that the same members as in Embodiment 1 are given the same numbers, and detailed descriptions thereof are omitted.

FIG. 5 is a schematic vertical cross-sectional view of an imaging module 10b according to the second embodiment. As shown in FIG. 5, the imaging module 10b includes a lens unit 20b for forming an image of a subject, and a camera unit 30b for converting the formed image into a video signal.

The lens unit 20b has a barrel 21b, a diaphragm 22, and a lens 23.

The lens barrel 21b is a cylindrical member with both ends opened. A diaphragm 22 and a lens 23 are arranged at predetermined positions inside the lens barrel 21b. The lens barrel 21 can be formed using, for example, a resin material. The lens barrel 21b can be formed using, for example, a resin material. The lens barrel 21b is attached to the camera unit 30b with an adhesive or the like via an adhesive flange 25, as in the first embodiment.

Further, the lens barrel 21b is provided with a through hole 26b at a position closer to the imaging element 31 than the adhesive flange 25 is.

The camera unit 30b includes a conductive member 36b in addition to the configuration of the camera unit 30 described above.

The connecting portion 32b connects the leg portion 24 and a conductive member 36b provided between the lens barrel 21b and the case 34 through a through hole 26b formed in the lens barrel 21b. The connecting portion 32b is made of a conductive material.

The conducting member 36b is sandwiched between the portion of the connecting portion 32b that protrudes outside the lens barrel 21b and the case 34, and is pressed from both sides. The conducting member 36b is flexible and has conductivity. For example, the conductive member 36b may be a sponge having a conductive film attached to its surface. Also, the conductive member 36b may be made of a material that itself has flexibility and conductivity. With such a configuration, since the conductive member 36b has flexibility, even if the dimension between the connecting portion 32b and the case 34 changes, it follows the change, and the connecting portion 32b and the case 34 are always kept in contact with each other. It is possible to maintain an electrically connected state.

Next, the configuration and function of the shield member 40b according to the second embodiment will be described with reference to FIG. 6 in addition to FIG.

A shield member 40b according to the second embodiment is composed of a diaphragm 22, a leg portion 24, a connecting portion 32b, and a conductive member 36b.

FIG. 6 is a perspective view of a diaphragm 22 and legs 24 according to the second embodiment. The leg portion 24 is a belt-like (or tongue-like) member extending from the outer edge of the circular diaphragm 22 and provided integrally with the diaphragm 22 . In addition, the length of the extension direction of the leg part 24 is short compared with 1st Embodiment.

The leg portion 24 extends from the diaphragm 22 toward the imaging element 31 and contacts the connection portion 32 . In addition, the number of the leg portions 24 may be one or plural. The inner wall of the lens barrel 21b is provided with grooves directed toward the imaging device, similarly to the lens barrel 21 of the first embodiment. The leg 24 is fitted into this groove. On the other hand, the connection portion 32b is also fitted into a groove provided in the inner wall of the lens barrel 21b, and one end side contacts the leg portion 24. As shown in FIG. As a result, the leg portion 24 and the connection portion 32b do not interfere with other components.

The other end side of the connection portion 32b protrudes outside the lens barrel 21b through a through hole 26b formed in the lens barrel 21b. A portion of the connecting portion 32b that protrudes outside the lens barrel 21b contacts the conducting member 36b.

In the configuration described above, the leg portion 24 extending from the diaphragm 22 is connected to the connecting portion 32b, and the connecting portion 32b is connected to the case 34 via the conducting member 36b. As a result, the diaphragm 22, the leg portion 24, the connecting portion 32b, and the conductive member 36b are electrically connected to the case 34, and thus have substantially the same potential as the case 34, that is, the GND potential of the sensor substrate 35 (image pickup device 31). They are at approximately the same potential.

With these configurations, the shield member 40b made up of the diaphragm 22, the leg portion 24, and the connection portion 32b can improve the electromagnetic shielding characteristics of the imaging module 10b.

Furthermore, by using the diaphragm 22 as the shield member 40b, it is possible to improve the electromagnetic shielding characteristics of the imaging module 10b without adding a new member.

It should be noted that the first and second embodiments described above describe imaging modules in which the diaphragm 22 has an electromagnetic shielding function. However, the shield member having the electromagnetic shielding function is not limited to the diaphragm 22 . The shielding member having the electromagnetic shielding function may be, for example, a light shielding plate that prevents light from entering from outside the effective beam diameter of the lens 23 . Further, in this case, the diaphragm 22 and the light shielding plate may be provided separately, and one or both of the plates may have the same configuration as the shield member 40 (40b) described above. At this time, the light blocking plate has an opening on the plane where the optical axis of the lens 23 intersects. The diameter of the opening of the light blocking plate is greater than or equal to the diameter of the opening 221 of the stop 22 and less than the inner diameter of the lens barrel 21 . These structures can reduce electromagnetic waves entering the imaging device 31 through the opening of the lens unit 20 .

It should be noted that the above-described embodiments are presented as examples and are not intended to limit the scope of the present disclosure. The above embodiment can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. The above-described embodiments are included in the scope or gist of the present disclosure, and are included in the invention described in the claims and their equivalents.

The imaging module according to the present disclosure can be used for, for example, an in-vehicle camera, a surveillance camera, a drone camera, and the like.

Reference Signs List 10, 10b imaging module 20, 20b lens unit 21, 21b lens barrel 22 diaphragm 221 opening 23 lens 24 leg 25b adhesive flange 26b through-hole 27 groove 30, 30b camera unit 31 imaging element 32, 32b connection 321 opening 33 screw 34 case 35 sensor substrate 36b conduction member 40, 40b shield member

Claims (9)

An imaging module comprising a conductive housing having an imaging element and a cylindrical lens barrel attached to the housing,
The lens barrel has a
a plurality of lenses arranged along the optical axis;
a metal plate provided between the plurality of lenses in contact with the inner wall of the lens barrel and having an opening on a surface intersecting the optical axis;
a connecting portion that electrically connects the metal plate and the housing;
with
The diameter of the opening of the metal plate is a size corresponding to the diameter of the light flux condensed by the lens positioned in front of the metal plate in the optical path along which the light entering the lens barrel reaches the imaging device. having
imaging module. The metal plate is arranged behind the lens positioned at the head of the light entering direction in the optical path along which the light entering the lens barrel reaches the imaging element.
The imaging module according to claim 1. The metal plate functions as a diaphragm,
The imaging module according to claim 1 or 2. The lens barrel further includes an aperture inside,
The diameter of the opening of the metal plate is equal to or greater than the diameter of the opening of the aperture.
The imaging module according to claim 1 or 2. The connecting portion includes one or more strip-shaped conductive members extending from the edge of the metal plate in the direction of the imaging device,
The lens barrel is attached to the housing with the end of the conductive member in contact with a connecting portion that electrically connects the imaging element and the housing.
The imaging module according to any one of claims 1 to 4. The connection portion protrudes to the outside of the lens barrel through a through hole provided in the lens barrel and abuts on the housing.
The imaging module according to any one of claims 1 to 5. The connection part and the housing are electrically connected via a flexible conductive member,
The imaging module according to claim 6. 6. The imaging module according to claim 5, wherein said strip-shaped conductive member extends from the edge of said metal plate along the inner wall of said lens barrel toward said imaging element. The inner wall of the lens barrel is provided with a groove toward the imaging element,
The strip-shaped conductive member is fitted in the groove to extend in the direction of the imaging device,
The imaging module according to claim 8.

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