JP2020071311A - Imaging device - Google Patents

Abstract

To provide an imaging device which is constituted so as to suppress a decrease in image quality due to processing at assembly time while having high airtightness.SOLUTION: The imaging device comprises: a front case; a rear case connected to the front case; a substrate accommodated in an internal space formed by the front and rear cases and having an imaging element mounted thereon; a lens frame for holding a lens and being supported by the front case; and a seal member arranged between the front case and the lens frame. A first opposing face of the front case that is approximately parallel to the optical axis near an end on the subject side has a clearance and faces, across it, a second opposing face that is approximately parallel to the optical axis of the lens frame, at least one of the first opposing face and the second opposing face having a recess, with the seal member arranged in the recess, and the front and rear cases being ultrasonic welded.SELECTED DRAWING: Figure 5

Description

  One embodiment of the present invention relates to an imaging device and the like.

  2. Description of the Related Art Conventionally, there is an imaging device in which a lens frame holding a lens and a substrate on which an imaging element is mounted are housed in a case. In recent years, the number of such imaging devices mounted on automobiles has increased. In such an in-vehicle image pickup device, since it is used in a state of being exposed to rain and wind, high waterproof performance is required. In order to obtain high waterproof performance, for example, there is an image pickup apparatus having a structure in which a front case and a rear case are welded to each other in a sealable manner and a waterproof seal member is arranged between the lens and the case. For example, Patent Document 1 discloses an imaging device having a configuration in which packing is arranged between a lens barrel and an outer case, and a front case and a rear case are ultrasonically welded to each other.

JP, 2011-164461, A

  In the image pickup apparatus having the configuration described in Patent Document 1, it is possible to obtain higher waterproof performance than the configuration in which the front case and the rear case are not welded. However, since the packing is arranged closer to the image sensor than the end portion on the subject side, vibration during ultrasonic welding may propagate to the lens and the lens position may shift. If the position of the lens shifts, the focus changes, and the image quality of the captured image deteriorates. Therefore, there is a demand for an imaging device having a configuration capable of suppressing deterioration of image quality while obtaining high waterproof performance.

  The present invention adopts the following means in order to solve the above problems and the like. In the following description, reference numerals and the like in the drawings are added in parentheses in order to facilitate understanding of the invention, but each constituent element of the present invention is not limited to these additions. It should be broadly interpreted to the extent technically understandable by a trader.

One means of the present invention is
Front case (1),
A rear case (7) connected to the front case,
Substrates (51, 52) housed in an internal space formed by the front case and the rear case, and mounting an image pickup element;
A lens frame (2) for holding the lens and supported by the front case;
A seal member (4) arranged between the front case and the lens frame,
In the front case, a first facing surface (11) that is substantially parallel to the optical axis near the end on the subject side has a gap with a second facing surface (21) that is substantially horizontal to the optical axis of the lens frame. Opposite
At least one of the first facing surface and the second facing surface has a recess (22),
The seal member (4) is disposed in the recess (22),
The front case and the rear case are ultrasonically welded,
It is an imaging device.

  In the image pickup apparatus having the above configuration, a large vibration energy is generated during ultrasonic welding of the front case and the rear case, and vibration is likely to propagate to the lens. The seal member is arranged. Therefore, it is possible to make it difficult for the vibration during ultrasonic welding to propagate to the lens frame. As a result, it is possible to prevent the lens held by the lens frame from being displaced, and it is possible to prevent the focus from being displaced from the image sensor. As a result, it is possible to prevent the image quality of the captured image from being deteriorated due to the focus shift.

In the above imaging device, preferably,
The lens frame supports the lens by point contact at three or more positions in a direction substantially perpendicular to the optical axis.

  According to the imaging device having the above configuration, since the lens frame holds the lens in three or more point contacts, it is possible to more effectively prevent the lens from being displaced due to vibration during ultrasonic welding. be able to. This makes it possible to more effectively prevent the focus from being displaced from the image sensor, and prevent the image quality of the captured image from being deteriorated due to the focus shift.

In the above imaging device, preferably,
The front case has an inclined surface (12) in the diameter-expanding direction on a surface of the front case, which is continuous from the first facing surface, on the side of the image sensor.

  According to the image pickup apparatus having the above configuration, the lens frame assembled with the seal member having a slightly larger outer diameter than the inner diameter of the front case can be easily incorporated into the front case. As a result, the lens frame and the front case are connected with high sealing performance via the seal member, and the sealing performance can be further enhanced, and the waterproof and dust-proof configuration can be achieved. it can.

FIG. 1 is an external perspective view of the image pickup apparatus as viewed from the front side. FIG. 2 is a plan view of the image pickup apparatus viewed from the front side. FIG. 3 is a sectional view of the image pickup apparatus. FIG. 4 is a cross-sectional view of the image pickup device. FIG. 5 is a sectional view of a portion where the seal member is arranged. FIG. 6 is an enlarged view of the welded portions of the front case and the rear case before ultrasonic welding. FIG. 7 is an enlarged view of the welded portions of the front case and the rear case after ultrasonic welding. FIG. 8 is a plan view of the lens and the lens frame when viewed from the front side. FIG. 9 is an enlarged plan view of a contact portion between the lens and the lens frame.

  The image pickup device of the present invention has a configuration in which a lens frame is incorporated in a case, a front case and a rear case are ultrasonically welded, and the lens frame and the front case are sealed by a seal member. One of the features is that the seal member is arranged in the recess near the end on the side.

An embodiment as a specific configuration example of the present invention will be described according to the following configurations. However, the embodiment described below is merely an example of the present invention and does not limit the technical scope of the present invention.
1. Embodiment 2. Supplementary information

  In this specification, the center position of the lens mounted in the image pickup apparatus and the center position of the light incident on the image pickup element is referred to as an "optical axis". An image pickup target located on the opposite side of the lens from the image pickup device is referred to as a “subject”. The direction in which the subject is located with respect to the image sensor is referred to as "front in the optical axis direction", "front side" or "subject side", and the direction in which the image sensor is located relative to the subject is "rear direction in the optical axis" and "rear side". Side "or" imaging element side ".

<1. Embodiment>
An embodiment of the present invention will be described with reference to FIGS. 1 and 2 are external views of the image pickup apparatus. FIG. 1 is a perspective view seen from the front side, and FIG. 2 is a plan view seen from the front side. 3 and 4 are cross-sectional views of the image pickup apparatus, but the positions of the cross sections are different. FIG. 3 is a sectional view at a position including the optical axis. FIG. 4 is a sectional view at a position displaced from the optical axis. FIG. 5 is a cross-sectional view of a connecting portion between the lens frame 2 and the front case 1 in which the seal member 4 is arranged. 6 and 7 are enlarged views of the ultrasonic welding portions of the front case 1 and the rear case 7, FIG. 6 is a diagram before ultrasonic welding, and FIG. 7 is a diagram after ultrasonic welding. FIGS. 6 and 7 are enlarged views of the position of “A” in FIGS. 3 and 4. FIG. 8 is a plan view of the lens 2a and the lens frame 2 when viewed from the front side. FIG. 9 is an enlarged view of a contact portion between the lens 2a and the lens frame 2 in FIG.

  The x-axis, y-axis, and z-axis are shown in each drawing. The axis that is parallel to the optical axis of the lens and that faces the subject when viewed from the image sensor is defined as the “z axis”. The axis perpendicular to the z-axis is defined as the "x-axis". In addition, an axis perpendicular to both the z axis and the x axis is defined as a "y axis". The x-axis, y-axis and z-axis form three-dimensional Cartesian coordinates. Hereinafter, the arrow direction of the z-axis may be referred to as the z-axis + side, the direction opposite to the arrow may be referred to as the z-axis-side, and the same applies to the other axes. That is, along the z-axis, the z-axis + side is the “rear side” or “optical axis direction rear”, and the z-axis − side is the “front side” or “optical axis direction front”.

  As shown in the figure, the image pickup apparatus of this embodiment includes a front case 1, a lens frame 2, a flange 3, a seal member 4, a first substrate 51, a second substrate 52, a flexible substrate 53, a shield plate 6, and a rear case. 7 is included.

<Front case 1>
The front case 1 is a member that forms a housing (case) of the imaging device together with the rear case 7, and is made of metal or resin. The front case 1 has an opening centered on the optical axis at the front in the optical axis direction. The lens 2a held by the lens frame 2 and the like are located in this opening. The rear side of the front case 1 in the optical axis direction is open so that it can be connected to the rear case 7, and has a substantially rectangular peripheral surface so as to cover the optical axis. Although specifically described later, the front case 1 and the rear case 7 are ultrasonically welded. By connecting the front case 1 and the rear case 7 to each other, an internal space for housing the lens frame 2, the flange 3, the first substrate 51, the second substrate 52, the flexible substrate 53, the shield plate 6, and the like is formed. ..

  A seal member 4 is arranged between the front case 1 and the lens frame 2. Specifically, as shown in FIG. 5, the seal member 4 is arranged in contact with a vertical surface 11 near the end of the front case 1 on the object side and substantially perpendicular to the optical axis.

  As shown in FIG. 4, the front case 1 has an extending portion 17 formed so as to extend rearward in the optical axis direction (on the z-axis + side). A screw hole into which the screw 8 can be inserted is formed in the extending portion 17. The flange 3 is fixed to the front case 1 by inserting the screw 8 into the screw hole of the extending portion 17 of the front case 1. A washer 81 made of an elastic material such as rubber is arranged between the screw 8 and the flange 3. Note that the washer 81 may be replaced with another member as long as it is a vibration damping member or a vibration suppressing member capable of suppressing the transmission of vibration.

<Lens frame 2>
The lens frame 2 is a cylindrical member that holds one or more optical members including the lens 2a and extends in the optical axis direction. The lens frame 2 is supported by the front case 1. The lens frame 2 may be supported by the front case 1 via the flange 3.

  The lens frame 2 has a vertical surface 21 that faces the vertical surface 11 of the front case 1 and is substantially perpendicular to the optical axis. A concave portion 22 is formed on the vertical surface 21 so as to be depressed annularly in the radial direction. That is, the recess 22 is formed in a groove shape extending in the circumferential direction. The seal member 4 is disposed in the recess 22. The seal member 4 is in contact with the radial surface of the recess 22 of the lens frame 2. The seal member 4 may be in contact with the surface of the recess 22 in the optical axis direction. However, if the seal member 4 is arranged so as to contact both the front and rear surfaces in the optical axis direction, the seal member 4 may be damaged when the seal member 4 expands due to heat or the like. It is arranged so as to contact only one surface.

  The optical members held by the lens frame 2 include spacers, aperture plates, optical filters, and the like, in addition to one or more lenses. The lens is made of a transparent material such as glass or plastic and refracts light from the front side in the optical axis direction while transmitting the light rearward in the optical axis direction. The spacer is a plate-shaped annular member having an appropriate thickness in the optical axis direction, and adjusts the position of each lens in the optical axis direction. The spacer has an opening at the center including the optical axis. The aperture plate determines the outermost position of the light passing through. The optical filter suppresses or shields light having a predetermined wavelength. The number and type of these optical members can be arbitrarily changed.

  When assembling the imaging device, the lens frame 2 is assembled in the front case 1 from the imaging device side (rear side) toward the subject side (front side) with the seal member 4 assembled. At this time, the seal member 4 is located at the outermost periphery, and the seal member 4 is pressed into the subject side while being in contact with the inclined surface 12 of the front case 1.

  As shown in FIG. 9, the lens frame 2 has a convex portion 2b protruding in a rib shape in the radial direction perpendicular to the optical axis. Six protrusions 2b are formed with a uniform sense in the circumferential direction. That is, the convex portions 2b are formed at 60 ° intervals. The convex portion 2b of the lens frame 2 is in point contact with the lens frame 2. That is, the lens frame 2 supports the lens 2a by radial fitting by making point contact at six points in the direction perpendicular to the optical axis. The lens frame 2 may be in contact with the lens 2a at three or more of the six convex portions 2b, and all the convex portions 2b may not be in contact with the lens 2a.

<Seal member 4>
The seal member 4 is an annular member formed of an elastic member such as rubber. The seal member 4 is arranged in the recess 22 formed in the lens frame 2, and is arranged between the front case 1 and the lens frame 2 in the assembled state. The seal member 4 is arranged in a state of being compressed in a radial direction perpendicular to the optical axis, connects the front case 1 and the lens frame 2 without a gap, and prevents moisture and dust from entering the case. To work.

<Rear case 7>
The rear case 7 is a member that forms a housing (case) of the image pickup device together with the front case 1, and is formed of metal, resin, or the like, like the front case 1. The rear case 7 is arranged behind the front case 1 in the optical axis direction. As described above, by being connected to the front case 1, an internal space for housing the lens frame 2, the flange 3, the first substrate 51, the second substrate 52, the shield plate 6 and the like is formed. The front side in the optical axis direction of the rear case 7 has substantially the same shape as the rear side in the optical axis direction of the front case 1, and is ultrasonically welded to the front case 1.

<Ultrasonic welding of front case 1 and rear case 7>
As shown in FIG. 6 before being ultrasonically welded, the front case 1 includes an end surface 16 rearward in the optical axis direction, surfaces 15 and 13 perpendicular to the optical axis, and an inclined surface 14 connecting the surface 15 and the surface 13. including. The rear case 7 includes front end faces 71 and 73 in the optical axis direction, and a face 72 that connects the end faces 71 and 73 and is perpendicular to the optical axis. The end surface 16 of the front case 1 and the end surface 73 of the rear case 7 face each other in the optical axis direction. The surface 15 of the front case 1 and the surface 72 of the rear case 7 face each other in the direction perpendicular to the optical axis. The inclined surface 14 of the front case 1 faces the corner formed by the end surface 71 and the surface 72 of the rear case 7.

  As shown in FIG. 7 in the state of ultrasonic welding, when ultrasonic waves are applied from the outside, the periphery of the fused portion including the corner formed by the end face 71 and the face 72 of the rear case 7 is melted and spread. To fill the gap between the front case 1 and the rear case 7. As a result, the front case 1 and the rear case 7 are ultrasonically welded.

<Flange 3>
The flange 3 is arranged in the internal space of the front case 1 and the rear case 7, and is connected to the rear case 7 and the lens frame 2. The flange 3 is screwed with the lens frame 2 in the radial direction. The flange 3 is screwed to the rear case 7.

<First substrate 51>
The first substrate 51 is a rigid substrate on which the image sensor 511 is mounted. Electronic components other than the image sensor 511 may be mounted on the first substrate 51. Since the image sensor 511 is mounted on the front surface of the first substrate 51 in the optical axis direction, the first substrate 51 is arranged along a plane perpendicular to the optical axis so that the image sensor 511 is irradiated with light during imaging. Will be placed. The first substrate 51 and the second substrate 52 are electrically connected by a flexible substrate or the like. The position of the first substrate 51 is fixed by being connected to the flange 3 with a screw or the like.

<Imaging element 511>
The imaging element 511 is a photoelectric conversion element that converts the emitted light into an electric signal, and is, for example, a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor. However, the image sensor 511 is not limited to the CCD image sensor or the CMOS image sensor. The image sensor 511 receives light that has passed through a lens or the like held by the lens frame 2 and converts it into an electric signal. The electric signal acquired by the image pickup element 511 is output as image data to the outside of the image pickup apparatus after being subjected to predetermined electric processing or signal processing by the electronic components mounted on the first board 51 and the second board 52. It

<Second substrate 52>
The second substrate 52 is a rigid substrate on which electronic components are mounted. Like the first substrate 51, the second substrate 52 is arranged along a plane perpendicular to the optical axis. That is, the first substrate 51 and the second substrate 52 are arranged in parallel with each other. The second substrate 52 is arranged behind the first substrate 51 in the optical axis direction. The second substrate 52 is connected to the front case 1 with a screw or the like and fixed in position. The second substrate 52 is further connected to the shield plate 6. The first substrate 51 and the second substrate 52 are electrically connected via the flexible substrate 53.

  It should be noted that the second substrate 52 is not an indispensable component in the image pickup apparatus, and may have only the first substrate 51. Further, in addition to the second board 52, a board on which an electronic component is mounted may be further included.

<Shield plate 6>
The shield plate 6 is formed of a plate-shaped member such as metal having conductivity. The shield plate 6 is arranged in an internal space formed by the front case 1 and the rear case 7 so as to cover the first substrate 51 and the second substrate 52. The shield plate 6 is preferably electrically connected to the ground potential. The shield plate 6 is connected to the second substrate 52 and fixed in position.

<Assembly procedure>
Here, a procedure for assembling the image pickup apparatus according to the present embodiment will be described. First, the lens frame 2 holding the lens 2a is screwed into the flange 3. Next, the first substrate 51 is connected to the flange 3 with a screw or the like. Here, the focus is adjusted by adjusting the positions of the lenses including the lens 2a with respect to the image sensor 511. Next, the lens frame 2 is radially fitted to the front case 1 with the seal member 4 interposed therebetween, the flange 3 is connected to the front case 1 with a screw 8, and the second substrate 52 and the front case 1 are connected with a screw or the like. To be done. Next, the shield plate 6 is inserted from the rear side in the optical axis direction to be connected to the second substrate 52. Next, the front case 1 and the rear case 7 are temporarily connected and firmly connected by ultrasonic welding.

  Here, when the front case 1 and the rear case 7 are ultrasonically welded, the vibration energy applied to the lens frame 2 at a position in front of the front case 1 in the optical axis direction (a position where the seal member 4 is arranged) is changed. It was confirmed by simulations that the position was larger. It is considered that this is due to the following phenomenon. That is, when the front case 1 and the rear case 7 are ultrasonically welded, ultrasonic vibration is applied to the front case 1 and the rear case 7. At this time, vibrations propagating from the front case 1 to the lens frame 2 and the lens 2a are mainly propagated through a path through the seal member 4 on the front side in the optical axis direction and a path through the extending portion 17 and the flange 3. Become. Here, the portion extending from the extending portion 17 via the flange 3 is formed to be relatively thicker than the portion of the front case 1 on the front side in the optical axis direction in which the seal member 4 is arranged, and the propagation of vibration to the lens frame 2 is prevented. It is suppressed to some extent. That is, the position in front of the front case 1 in the optical axis direction is the main propagation path of the vibration to the lens frame 2. Therefore, suppressing the vibration propagation at this position is effective in suppressing the displacement of the position of the lens 2a due to the vibration during ultrasonic welding.

  The image pickup apparatus according to the present embodiment is provided between the vertical surface 11 near the subject-side end of the front case 1 where large vibration energy is generated during ultrasonic welding and the vertical surface 21 of the lens frame 2 facing the vertical surface 11. The seal member 4 is disposed in the recess 22 provided in the. Therefore, the vibration when the front case 1 and the rear case 7 are ultrasonically welded is suppressed by the seal member 4, and it is difficult for the vibration to propagate to the lens frame 2. As a result, it is possible to prevent the lenses 2a and the like held by the lens frame 2 from being displaced, and it is possible to prevent the focus from being displaced from the image sensor 511. As a result, it is possible to configure an image pickup apparatus that prevents the deterioration of the image quality of the imaged image due to the focus shift.

  Although the recess 22 is formed on the vertical surface 21 of the lens frame 2 in the embodiment, the recess in which the seal member 4 is disposed may be formed on the vertical surface 11 of the front case 1. Alternatively, in addition to the recesses 22, recesses may be formed in the vertical surface 11 of the front case 1, and the seal member 4 may be arranged in these recesses. Even with these configurations, the same effects as above can be obtained.

  Further, the image pickup apparatus according to the present embodiment has a configuration in which the lens frame 2 supports the lens 2a by making point contact with the lens 2a at six locations (or three or more locations) in the radial direction perpendicular to the optical axis. It is configured to more effectively prevent the lens from being displaced due to vibration at the time. This makes it possible to more effectively prevent the focus from being displaced from the image sensor, and prevent the image quality of the captured image from being deteriorated due to the focus shift.

  Further, in the image pickup apparatus according to the present embodiment, the front case 1 has a configuration in which the vertical surface 11 has an inclined surface 12 at a position continuous with the image pickup element side. Therefore, the lens frame 2 assembled with the seal member 4 having an outer diameter slightly larger than the inner diameter of the front case 1 can be easily incorporated into the front case 1 from the image pickup device side. As a result, the lens frame 2 and the front case 1 are connected with high sealing performance via the seal member 4, and the sealing performance can be further enhanced, resulting in a configuration having higher waterproofness and dustproofness. can do.

<2. Supplementary items>
The features of the embodiment of the present invention and the configuration of the present invention have been described above. The above description is merely an example of the present invention, and the scope of the present invention is not limited to the above description, but is broadly construed to a range that can be grasped by those skilled in the art based on the description of each embodiment. Is.

  For example, in the embodiment, the configuration in which the vertical surface 11 of the front case 1 and the vertical surface 21 of the lens frame 2 are both surfaces perpendicular to the optical axis has been described, but the vertical surface 11 and the vertical surface 21 are described. May not be perfectly perpendicular to the optical axis and may have an inclination.

  INDUSTRIAL APPLICABILITY The present invention is suitably used as an in-vehicle image pickup device and the like.

DESCRIPTION OF SYMBOLS 1 ... Front case 11 ... Vertical surface 12 ... Inclined surface 17 ... Extension part 2 ... Lens frame 2a ... Lens 2b ... Convex part 21 ... Vertical surface 22 ... Recess 3 ... Flange 4 ... Seal member 51 ... 1st board | substrate 511 ... Imaging element 52 ... Second substrate 53 ... Flexible substrate 6 ... Shield plate 7 ... Rear case 8 ... Screw 81 ... Washer

Claims (3)

Front case,
A rear case connected to the front case,
A substrate that is housed in an internal space formed by the front case and the rear case and has an image sensor mounted thereon;
A lens frame that holds the lens and is supported by the front case;
A seal member arranged between the front case and the lens frame,
In the front case, a first facing surface that is substantially parallel to the optical axis near the end on the subject side faces a second facing surface that is substantially parallel to the optical axis of the lens frame with a gap,
At least one of the first facing surface and the second facing surface has a recess,
The seal member is disposed in the recess,
The front case and the rear case are ultrasonically welded,
Imaging device. The lens frame supports the lens by point contact at three or more positions in a direction substantially perpendicular to the optical axis,
The image pickup apparatus according to claim 1. The front case has an inclined surface in the diameter-expanding direction on the surface on the image pickup element side that is continuous from the first facing surface,
The image pickup apparatus according to claim 1.

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