Patent ID: 12256134

DESCRIPTION OF THE EMBODIMENTS

Referring now to the accompanying drawings, a detailed description will be given of embodiments according to the disclosure.

First Embodiment

Referring now toFIGS.1to6, a description will be given of a camera module (image pickup apparatus)1according to a first embodiment of the disclosure.FIG.1is a perspective view of the camera module1.FIG.2is a sectional view of the camera module1.FIG.3is an exploded perspective view of the camera module1viewed from an object side.FIG.4is an exploded perspective view of the camera module1viewed from an image sensor side (image side).FIG.5is a perspective view of a state without a fixing member15.FIG.6is a rear view without a cover13and the fixing member15.

A holding frame (housing)2of the camera module1is made of metal with high thermal conductivity such as aluminum die-casting, and includes an inner diameter threaded portion2a, a circular opening2b, and a rectangular opening2c. The lens unit3includes a lens frame30and lenses31,32, and33and is inserted into the circular opening2bof the holding frame2. An outer diameter portion of the lens frame30includes an outer diameter threaded portion30a. In a case where the outer diameter threaded portion30aand the inner diameter threaded portion2aof the holding frame (housing)2are engaged with each other, the lens unit3is held by the holding frame2so that the position of the lens unit3in a direction along an optical axis OA (optical axis direction) is adjustable. While the lens frame30is configured to hold the lenses31,32, and33in this embodiment, the holding frame2may be configured to hold the lenses31,32, and33.

A first circuit board6is an imaging board. The first circuit board6is mounted with an image sensor5, a connector6a, and an electric element (not illustrated). In the mounting portion of the image sensor5on the first circuit board6, a rectangular opening6bis formed at a position corresponding to the back surface of the image sensor5(surface opposite to a light-receiving surface facing the object side). The opening6bis provided so as to expose the back surface of the image sensor5. The first circuit board6is fixed to a sensor sheet metal7with screws4while the position of the first circuit board6is adjusted so that the center of the light-receiving surface of the image sensor5approximately coincides with the optical axis OA of the lens unit3in a direction orthogonal to the optical axis OA. The sensor sheet metal7is attached to a receiving portion (not illustrated) provided inside the rectangular opening2cin the holding frame2and fixed with screws8.

The camera module1can image the desired scene by imaging light rays condensed by the lens unit3on the image sensor5. The positions of the lens unit3and the light-receiving surfaces of the image sensor5are different from individual to individual due to manufacturing variations in components and assembly. In a case where manufacturing variations are large relative to the depth of focus, the focus position of the lens unit3and the position of the light-receiving surface of the image sensor5may not coincide within the range of the depth of focus after the assembly with no care. In such a case, it is necessary to adjust the focus position of the lens unit3and the position of the light-receiving surface of the image sensor5during assembly so that they coincide within the range of the depth of focus. Therefore, optical position adjustment (focusing) is made while the focus performance is confirmed with a captured image or an evaluation value for the image.

More specifically, the optical position adjustment is made by providing an evaluation chart in front (on the object side) of the lens unit3, by confirming the resolution and contrast value from the captured chart image, and by moving the lens unit3in the optical axis direction to a position that satisfies the required image quality. In order to maintain the adjusted image quality, it is important to maintain the relative positions between the lens unit3and the image sensor5in the optical axis direction. However, in a case where a load is applied to the image sensor5or the first circuit board6mounted with the image sensor5, the position of the image sensor5in the optical axis direction changes over time and the image quality may deteriorate. Therefore, it is necessary to reduce the load applied to the image sensor5or the first circuit board6in the optical axis direction.

A second circuit board11is a control board. A second circuit board11is placed opposite to the first circuit board6. Connectors11aand11band an electric element11cas a heat source are mounted on the second circuit board11. The connector11aa of the second circuit board11is inserted into the connector6aof the first circuit board6, and the first circuit board6and the second circuit board11are fixed to the sensor sheet metal7with screws12while the first circuit board6and the second circuit board11are electrically connected. A cable (not illustrated) is connected to the connector11bof the second circuit board11. Power supply to the second circuit board11and electric signal transmission and reception are made through the cable. In this embodiment, the first circuit board6and the second circuit board11are electrically connected by the connectors6aand11a, but the disclosure is not limited to this embodiment. Instead of the connectors, they may be electrically connected via an FPC (Flexible Printed Circuit), an FFC (Flexible Flat Cable), or the like.

The cover13is fixed to the holding frame2with screws14so as to cover the back surface of the second circuit board11. One end9aof a heat radiating sheet9is disposed inside the opening6bformed in the first circuit board6and contacts the back surface of the image sensor5. The other end9bof the heat radiating sheet9is disposed so as to contact the outer surface of the rectangular opening2cin the holding frame2. The heat radiating sheet9is made of a material having high thermal conductivity such as a graphite sheet, and radiates the heat emitted from the image sensor5to the holding frame2. The heat radiating sheet9is placed between the first circuit board band the second circuit board11.

A flexible member10includes a thermally conductive gel member that uses, as a base material, silicone that is applicable in a free shape by a dispenser. The flexible member10is made of a soft material and is easily moved or deformed in a case where an external force is applied. In a case where there is a sufficient area around the flexible member10that allows the flexible member10to move or deform, the flexible member10itself will not be substantially compressed and the load generated by sandwiching the flexible member10will be small. In the optical axis direction of the lenses31,32, and33, the first circuit board6, the heat radiating sheet9, the flexible member10and the second circuit board11are arranged in that order.

The flexible member10is applied to the surface of the one end9aof the heat radiating sheet9opposite to the surface that contacts the image sensor5. By fixing the second circuit board11to the sensor sheet metal7with a predetermined application amount of the flexible member10, the flexible member10is sandwiched and pressed between the heat radiating sheet9and the second circuit board11. At this time, the flexible member10moves or deforms following the surface shapes of the heat radiating sheet9and the second circuit board11, and the flexible member10and contacts the heat radiating sheet9and the second circuit board11.

In this embodiment, the position where the flexible member10contacts the second circuit board11overlaps at least part of a projection portion in the optical axis direction of the electric element11cas the heat source mounted on the second circuit board11. In other words, at least part of the contact position between the flexible member10and the second circuit board11overlaps at least part of the projection position of the electric element11cin the optical axis direction. Thereby, the heat emitted from the electric element11ccan be more efficiently radiated to the holding frame2via the flexible member10and the heat radiating sheet9.

The one end9aof the heat radiating sheet9is pressed against the back surface of the image sensor5by the flexible member10, and the adhesion performance between the heat radiating sheet9and the image sensor5can be improved with a small load. The other end9bof the heat radiating sheet9is fixed to and pressed against the holding frame2by the fixing member15, which is an adhesive tape (tape material), and the adhesion performance between the heat radiating sheet9and the holding frame2can be improved. By improving the adhesion performance between the heat radiating sheet9and the image sensor5and the holding frame2, the heat radiation from the image sensor5and the electric element11cto the holding frame2can be improved. As a consequence, the image sensor5can be prevented from becoming hot and the performance of the image sensor5can be maintained.

As described above, this embodiment can realize an image pickup apparatus that can efficiently radiate heat from the image sensor and make small the load applied to the image sensor in a configuration where the imaging board and the control board are stacked in the optical axis direction.

Second Embodiment

Referring now toFIGS.7to9, a description will be given of a camera module (image pickup apparatus)1aaccording to a second embodiment of the disclosure.FIG.7is a sectional view of the camera module1a.FIG.8is an exploded perspective view of the camera module1aviewed from the object side.FIG.9is an exploded perspective view of the camera module1aviewed from the image sensor side (image side). Those elements in this embodiment, which are corresponding elements in the first embodiment, will be designated by the same reference numerals, and a description thereof will be omitted.

The first circuit board6is adhered to the sensor sheet metal7in a position-adjusted state where the center of the light-receiving surface of the image sensor5substantially coincides with the optical axis OA of the lens unit3in the direction orthogonal to the optical axis. The first circuit board6in this embodiment has no opening6b, unlike the first embodiment. The sensor sheet metal7is adhered to a receiving portion (not illustrated) provided inside the rectangular opening2cin the holding frame2.

The one end9aof the heat radiating sheet9is disposed so as to contact the board surface of the first circuit board6. The other end9bof the heat radiating sheet9is disposed so as to contact the outer surface of the rectangular opening2cin the holding frame2. The heat radiating sheet9radiates the heat emitted from the image sensor5to the holding frame2via the first circuit board6.

The flexible member10is applied to the surface of the one end9aof the heat radiating sheet9opposite to the surface that contacts the first circuit board6, and is sandwiched and pressed between the heat radiating sheet9and the second circuit board11. Thereby, the heat emitted from the electric element11ccan be radiated to the holding frame2via the flexible member10and the heat radiating sheet9.

The one end9aof the heat radiating sheet9is pressed against the board surface of the first circuit board6by the flexible member10, and the adhesion performance between the heat radiating sheet9and the first circuit board6can be improved with a small load. By improving the adhesion performance between the heat radiating sheet9and the first circuit board6and the holding frame2, the heat radiation from the image sensor5and the electric element11cto the holding frame2can be improved. As a consequence, the image sensor5can be prevented from becoming hot and the performance of the image sensor5can be maintained.

As described above, this embodiment can realize an image pickup apparatus that can efficiently radiate heat from the image sensor and make small the load applied to the image sensor in a configuration where the imaging board and the control board are stacked in the optical axis direction.

While the disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2021-205129, filed on Dec. 17, 2021, which is hereby incorporated by reference herein in its entirety.