JP5078578B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus such as a surveillance camera.

  In general, a so-called surveillance camera is installed in a commercial facility such as a store or bank, a production line of an industrial facility such as a factory, or a public facility such as a subway or an arcade for the purpose of safety management. This kind of surveillance camera is often installed in a place where people come and go, so as not to give the subject a sense of discomfort that it is being monitored, and to prevent it from being easily detected by criminals In addition, miniaturization as much as possible has been demanded.

  In order to meet such demand, a small surveillance camera using a CCD, which is a photoelectric conversion element, has appeared and has been widely used. However, in exchange for miniaturization of the device, the density of component mounting has increased, and as a result, the temperature of the air in the surveillance camera body has increased. In addition, surveillance cameras need to be photographed without leaking crimes and abnormalities that occur infrequently, so continuous operation must be performed day and night, and it will not be possible to stop the high internal air temperature. ing. Furthermore, as the image quality is improved, the amount of data and the amount of heat generated by the CPU mounted on the camera unit are constantly increasing, and the situation is getting worse.

  It is known that a CCD, which is a photoelectric conversion element mounted on a surveillance camera, has a unique characteristic that a dark current flows even if there is no light input, and this dark current amount increases as the temperature increases. . As the dark current increases, the dynamic range of the signal decreases and the S / N ratio of the imaging signal decreases, so that a photoelectric conversion error is likely to occur. Due to this conversion error, so-called white scratches appear in the video, causing a problem of video degradation. As described above, as the air temperature in the surveillance camera body becomes higher and higher, the problem of such image deterioration becomes more serious.

In view of these circumstances, various heat dissipation structures have been proposed as means for cooling the CCD. In the video camera described in Patent Document 1, a heat transfer plate facing the opening surface of the through hole is provided behind the front plate through the image pickup device, and between the heat transfer plate and the image pickup device, and between the heat transfer plate and the camera housing. A heat dissipating structure with a first heat conductive rubber and a second heat conductive rubber interposed therebetween is employed.
Moreover, in the thing of patent document 2, while installing CCD in a wiring board, arrange | positioning the heat absorption case which encloses the main body with respect to this CCD, and also connecting the said heat absorption case and an exterior panel, and integrating Is adopted.

Japanese Patent Laid-Open No. 7-154658

  In Patent Document 1, a heat transfer member is arranged in the CCD and the housing, heat diffusion and heat transfer are promoted, and a low thermal resistance to the housing is realized. However, there is a problem that the heat transfer structure integrated with the CCD increases the effective surface area of the CCD, making it easy to receive the heat of air.

  Furthermore, it demonstrates in detail using FIG. 4A is a perspective view of the inside of a camera head unit according to the prior art, and FIG. 4B is a cross-sectional view of the camera head unit. In these drawings, a lens barrel 12 is accommodated in a housing 11 of a camera head unit 10, and a lens group 13 having a zoom function or a focus function is arranged in the lens barrel 12. An imaging element 14 made of a CCD is disposed behind the optical axis of the lens group 13. Here, in the drawing, the front and rear are represented by arrows Fr and Rr.

  The image sensor 14 is mounted on a substrate 15 and a diffusion plate 16 for heat dissipation is attached. In this example, two motors 17 and 18 are disposed on the side surface of the lens barrel 12, and these motors 17 and 18 drive the lens group 13 in the lens barrel 12 and are used as a driving source for zoom and focus. .

  In such an imaging apparatus, the motors 17 and 18 are frequently used and become extremely hot. And the motors 17 and 18 which became high temperature warm the air in the housing | casing 11. FIG. Further, when a sufficient convection area cannot be secured, the air stays in the vicinity of the motors 17 and 18 and circulates almost without going to other parts. Also, the CCD constituting the image sensor 14 is often arranged at a position close to the motors 17 and 18 on the end surface of the lens barrel 12. For this reason, there is a problem that the heated and stagnant air in the vicinity of the motors 17 and 18 surrounds the CCD and causes a further increase in temperature.

  In view of such circumstances, an object of the present invention is to provide an imaging apparatus that effectively and appropriately suppresses temperature rise and ensures proper operation.

An image pickup apparatus according to the present invention includes an image pickup element that converts light collected by a lens group into an electrical signal, a substrate on which the image pickup element is mounted, and the image pickup element disposed between the image pickup element and the substrate. A diffusion plate that diffuses heat; a motor that is disposed on a side surface of a lens barrel that houses the lens group; and that drives the lens group; a bottom plate portion that is interposed between the lens barrel and the diffusion plate; a septum wall air heated by operation of the motor and a diaphragm unit provided on the periphery of the bottom plate portion you isolated from the air surrounding the imaging element, the imaging element, the substrate, the diffusion plate A housing for housing the lens barrel, the motor, and the partition wall, and being in pressure contact with an inner wall of the housing in an integrated state with the diffusion plate, so that the diffusion plate and the housing can conduct heat. A heat transfer plate to be connected and a support that rotatably supports the casing. And having a part.

  According to the present invention, the partition wall is provided so as to cover the image pickup device, and in particular, the air heated by the operation of the motor is prevented from entering the image pickup device side. Thereby, the temperature rise of the air in the vicinity of the image sensor is prevented, and the thermal influence on the CCD can be effectively suppressed.

Hereinafter, preferred embodiments of an imaging apparatus according to the present invention will be described in detail using the same reference numerals for members that are substantially the same as or correspond to those of a conventional example, based on the drawings.
(First embodiment)
1 and 2 show a first embodiment of the imaging apparatus of the present invention. First, in FIG. 1, reference numeral 10 denotes a camera head unit incorporating an optical lens or an optical lens group and an imaging system, and 1 denotes a base unit incorporating a power source, an image processing circuit, and the like. The base portion 1 is rotatably supported on a base (not shown), and can be rotated around the pan axis 2 (FIG. 1, arrow A). Further, a support column 3 of the camera head unit 10 is erected on the base unit 1, and the camera head unit 10 is supported by the support column 3 so as to be rotatable around the tilt axis 4 (FIG. 1, arrow B).

  As described above, the camera head unit 10 mounted on the base unit 1 can rotate about the pan axis 2 and the tilt axis 4 by an operation of an operator or the like, and can operate in an arbitrary direction. This imaging device is used as a surveillance camera, for example, and can capture a desired image at the installation location.

  Next, FIG. 2A is a perspective view of the inside of the camera head according to the present invention, and FIG. 2B is a cross-sectional view of the camera head. In this embodiment, the basic configuration of the imaging apparatus is substantially the same as that of the conventional example (FIG. 4). That is, in FIG. 2, a lens barrel 12 is accommodated in the housing 11 of the camera head unit 10, and a lens group 13 having a zoom function or a focus function is arranged in the lens barrel 12. An imaging device 14 made of a CCD is disposed behind the optical axis of the lens group 13. Here, in the drawing, the front and rear are represented by arrows Fr and Rr.

  The image sensor 14 is mounted on a substrate 15 and a diffusion plate 16 for heat dissipation is attached. The diffusion plate 16 is fixed integrally with the image sensor 14. Two motors 17 and 18 are disposed on the side surface of the lens barrel 12, and these motors 17 and 18 drive the lens group 13 in the lens barrel 12 and are used as a drive source for zoom and focus control. It is done.

  The image sensor 14 composed of a CCD or the like is mounted on the substrate 15 as described above, converts the light collected by the lens group 13 into an electrical signal, and outputs image data. During this conversion, heat is generated with a small amount, and the imaging element 14 is heated by its own heat. Since the image sensor 14 is vulnerable to temperature rise, a diffusion plate 16 made of a material having high thermal conductivity such as aluminum is attached to the image sensor 14. The diffusion plate 16 diffuses local heat of the image sensor 14 to prevent an excessive temperature rise.

  The lens barrel 14 has a lens group 13 composed of a plurality of optical lenses, and the lens group 13 is driven by motors 17 and 18 to control zoom and focus. The usage frequency and power consumption of the motors 17 and 18 are very high, and the temperatures of the motors 17 and 18 and the air surrounding them are high.

  In the present embodiment, a partition wall 19 is disposed so as to surround the diffusion plate 16 and the substrate 15. The partition wall 19 is for isolating the air in the housing heated by the motors 17 and 18 from the air around the substrate 15 (image sensor 14) so that the air does not enter the vicinity of the image sensor 14. The material of the partition wall 19 is desirably a material having a low thermal conductivity such as rubber, urethane, sponge, elastomer, or plastic.

  The partition wall 19 covers the diffusion plate 16 and the substrate 15. For example, as shown in FIG. 2B, the bottom plate portion 19a of the partition wall 19 is inserted between the diffuser plate 16 and the rear end face of the lens barrel 14, and the partition plate portion 19b rises from the periphery of the bottom plate portion 19a. A partition wall 19 having a bottom structure can be formed. Thereby, it can isolate from the air warmed by the motors 17 and 18. In this example, an opening for exposing the image sensor 14 is provided at a substantially central portion of the bottom plate portion 19a. This is because the image sensor 14 needs to receive light. As described above, the partition wall 19 that covers the mounting portion (mainly the substrate 15 and the diffusion plate 16) of the image sensor 14 is provided in the space inside the housing 11 behind the lens barrel.

  In addition, it is effective even if a plate-like partition is formed between the motors 17 and 18 and the imaging device 14 and the diffusion plate 16 and the substrate 15 (position corresponding to the bottom plate portion 19a) to increase the airflow resistance. Furthermore, the partition wall 19 is a simple box-shaped rectangle in the illustrated example. However, the present invention is not limited to this illustrated example, and if a curved surface that follows the curved surface of the inner surface of the housing 11 is formed, the two are in close contact with each other. Improves.

  According to the present embodiment, the partition wall 19 that covers the mounting portion (mainly the substrate 15 and the diffusion plate 16) of the image sensor 14 is provided behind the lens barrel. As a result, air heated by the operation of the motors 17 and 18 is prevented from flowing into the image sensor 14 side. As a result, the temperature rise of the air in the vicinity of the image sensor 14 is prevented, and the thermal influence on the image sensor can be effectively suppressed. Therefore, the above-described problems caused by the dark current can be solved, and the image quality and quality of the image obtained by the imaging apparatus can be improved. Further, by preventing the temperature rise, not only can the durability of the imaging device be improved, but also there are advantages that the configuration is relatively simple and the cost is advantageous.

(Second Embodiment)
Next, the imaging apparatus according to the present embodiment will be described. Here, the description of what has been described in the first embodiment will be omitted.
FIG. 3 shows an imaging apparatus according to the second embodiment. In FIG. 3, the heat transfer plate 20 is integrally attached to the diffusion plate 16 with screws or the like, and is elastically pressed against the inner wall of the housing 11 in an integrated state. Thereby, the diffusion plate 16 and the housing | casing 11 are connected so that heat transfer is possible. The heat transfer plate 20 is covered with a partition wall 19.

  In the present embodiment, the heat transfer plate 20 has a substantially trapezoidal cross-sectional shape, and is coupled to the diffusion plate 16 at both ends of the bottom side of the trapezoid. Further, the upper side of the trapezoid is in elastic contact with the inner wall of the housing 11 as shown. Furthermore, as shown in FIG. 3A, both sides of the heat transfer plate 20 are open. The cross-sectional shape of the heat transfer plate 20 is not limited to the illustrated example, and may be formed in a “U” shape or the like.

  As described above, the elastic force that presses the heat transfer plate 20 against the inner wall of the housing 11 can use the elastic force of the heat transfer plate 20 itself. The heat transfer plate 20 is formed of an aluminum (or aluminum alloy) sheet metal having a high thermal conductivity, and connects the image sensor 14 and the housing 11 in a state of low thermal resistance.

  In the camera head unit 10 configured in a hermetically sealed casing, the part having the lowest temperature is the casing 11 that is in direct contact with the outside air. In the second embodiment, by connecting the housing 11 and the image sensor 14 through the heat transfer plate 20 in a low thermal resistance state, the temperature rise of the image sensor 14 can be significantly reduced. Therefore, even in the case of the second embodiment, in combination with the above-described partition wall 19, it is possible to prevent an increase in the temperature of the air in the vicinity of the image sensor 14 and to effectively suppress the thermal effect on the image sensor 14.

In order to further reduce the thermal resistance, the heat transfer area of the heat transfer plate 20 is increased, the heat transfer distance is shortened, and a high thermal conductivity member (such as copper) may be used. In addition, the larger the area of the portion where the heat transfer plate 20 is in contact with the housing 11, the greater the effect.
Further, a heat conductive rubber (not shown) may be interposed between the housing 11 and the heat transfer plate 20, so that the heat conductive rubber elastically deforms and absorbs the impact against an external impact. The image sensor 14 can be prevented from being subjected to a large impact.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the illustrated examples of the embodiments, and can be modified within the scope of the present invention.
For example, in the imaging device of the present invention, the partition wall 19 and the heat transfer plate 20 can be provided with either one alone, and the effects of each can be obtained.

It is a perspective view which shows the whole structure of an imaging device. It is the perspective view and sectional drawing which show the structural example inside the housing | casing in 1st Embodiment of an imaging device. It is the perspective view and sectional drawing which show the structural example inside the housing | casing in 2nd Embodiment of an imaging device. It is the perspective view and sectional drawing which show the structural example inside the camera head part in the imaging device which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base part 2 Pan axis | shaft 3 Support | pillar 4 Tilt axis | shaft 10 Camera head part 11 Housing | casing 12 Lens barrel 13 Lens group 14 Image pick-up element 15 Board | substrate 16 Diffusion plates 17 and 18 Motor 19 Partition 20 Heat-transfer plate

Claims (2)

An image sensor that converts light collected by the lens group into an electrical signal;
A substrate on which the image sensor is mounted ;
A diffusion plate disposed between the image sensor and the substrate for diffusing heat of the image sensor;
A motor that is disposed on a side surface of a lens barrel that houses the lens group and drives the lens group;
A bottom plate portion interposed between the lens barrel and the diffusion plate, and a partition plate portion provided around the bottom plate portion, and air heated by the operation of the motor and the septal wall that be isolated from the air,
A housing that houses the imaging device, the substrate, the diffusion plate, the lens barrel, the motor, and the partition;
A heat transfer plate that is in pressure contact with the inner wall of the casing in a state of being integrated with the diffusion plate and connects the diffusion plate and the casing in a heat transferable manner;
An imaging apparatus comprising: a support portion that rotatably supports the housing .   The imaging apparatus according to claim 1, wherein the partition wall has an opening for exposing the imaging element.

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