JP5247309B2 - Image sensor cooling device - Google Patents

Description

  The present invention relates to an imaging element cooling apparatus that can be attached to and detached from an imaging apparatus that includes an imaging element.

  In an image pickup apparatus (particularly a digital still camera) using an image pickup element such as a CCD or CMOS, noise may occur in an image due to the influence of dark current.

  Although current image pickup devices are considerably taking countermeasures against noise, this dark current noise is conspicuous even when the signal gain is increased (when gain is increased). This noise increases as the temperature of the image sensor increases. Therefore, a technique has been proposed in which the imaging element is cooled using an electronic cooling element such as a Peltier element to suppress noise.

For example, in Patent Document 1, an electronic cooling element is disposed on the back surface of an image pickup element to absorb heat generated by the image pickup element, and a heat dissipation member is provided on the back surface of the electronic cooling element. In Patent Document 2, the image pickup device is not normally cooled, and the image pickup device is cooled by filling a cooling member on the back surface of the image pickup device when necessary.
JP 2006-033031 A JP 2001-268420 A

  However, in Patent Document 1, although the cooling efficiency of the imaging device is large, the imaging device becomes thick in the thickness direction (the direction of the photographing optical axis). In view of this point, if it is attempted to reduce the thickness of the imaging device, the heat dissipation member and the electronic cooling element are reduced in size, and the cooling efficiency is lowered.

  Also in Patent Document 2, although the cooling efficiency of the imaging element is high, the imaging device becomes thick in the thickness direction. Further, a recent image pickup apparatus is generally provided with a liquid crystal monitor on the back surface. Therefore, in the structure as described above, there is a problem that a large liquid crystal monitor cannot be arranged because it interferes with the filling port of the cooling member.

(Object of invention)
An object of the present invention is to provide an image sensor cooling device that is thin and has a high cooling effect.

In order to achieve the above object, the present invention provides an image sensor cooling device that can be attached to and detached from an image pickup device including an image pickup device, wherein the image pickup device cooling device is attached to and detached from a bottom surface of the image pickup device; Based on the output of the temperature detection means for detecting the temperature of the image pickup device, the electronic cooling means for cooling the image pickup device, and the output of the temperature detection means when the image pickup device cooling device is attached to the image pickup device. the electrons and cooling control means for controlling the driving of the cooling means, possess a battery housing portion carrying the power supplied to the electronic cooling means, the heat radiating plate fin connected to an electronic cooling means, the heat radiating plate fins, the battery housing portion, and the cooling control means, said across the thermoelectric cooling means is arranged between the imaging element opposite and the this and the image pickup element cooling device disposed in a direction parallel to the bottom surface portion Than is.

  Similarly, in order to achieve the above object, the present invention provides an image sensor, a heat conducting member that conducts heat generated in the image sensor to the bottom surface, and the bottom surface when the heat generated in the image sensor is lower than a specified temperature. An image sensor cooling device that can be attached to and detached from an image pickup apparatus having a member that changes the position of the heat conduction member so that the heat conduction member does not come into contact with the heat conduction member. An attachment / detachment unit for attaching / detaching the device, a cooling unit for contacting the heat conducting member of the image pickup device when the device is attached to the image pickup device, and cooling the image pickup device via the heat conducting member; The imaging device cooling apparatus includes a cooling driving unit that drives the cooling unit with a constant power.

  Similarly, in order to achieve the above object, the present invention provides an imaging device, temperature detection means provided in the vicinity of the imaging device, and cooling capability reduction means for reducing the cooling capability of the imaging device cooling device attached to the imaging device. And a cooling capacity control means for controlling the reduction of the cooling capacity of the image sensor cooling device by controlling the driving of the cooling capacity reducing means when the temperature of the image sensor becomes lower than a specified temperature. An image sensor cooling device, an attachment / detachment unit for attaching and detaching the image sensor cooling device to a bottom surface portion of the image sensor, a cooling means for cooling the image sensor when mounted on the image sensor, and the cooling The image pickup device cooling apparatus includes cooling drive means for driving the means with constant power.

  According to the present invention, it is possible to provide an image sensor cooling device that is thin and has a high cooling effect.

  The best mode for carrying out the present invention is as shown in Examples 1 to 4 below.

  FIG. 1 is a side sectional view showing an image pickup apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 11 denotes a camera body, 12 denotes a lens barrel that can be attached to and detached from the camera body 11 via a mount 14, and 13 denotes a photographing optical system provided in the lens barrel 12.

  The subject image captured by the photographing optical system 13 is reflected by the quick return mirror 15 and incident on the pentaprism 16 at the time of observing the subject, and is then provided to the photographer as a subject image via the eyepiece optical system 17. A finder optical system is formed by the pentaprism 16 and the eyepiece optical system 17.

  The quick return mirror 15 is a half mirror. The subject luminous flux that has passed through the quick return mirror 15 is reflected by the sub mirror 18, passes through the field lens 19, the AF (autofocus) mirror 110, and the eyeglass lens 111, and forms an image on the surface of the AF sensor 112. The AF sensor 112 detects defocus based on the phase difference between the two images via the spectacle lens 111.

  The field lens 19, the AF mirror 110, the eyeglass lens 111, and the AF sensor 112 constitute a known focus detection device.

  A heat conducting member 119 such as a graphite sheet is in contact with the back surface of the imaging circuit board 115 to which the back surface side of the imaging surface of the image sensor 114 (the surface facing the imaging optical system 13) is attached. The heat conducting member 119 includes at least two planes: a first surface 119 a that contacts the back surface of the image sensor 114 via the image pickup circuit board 115, and a second surface 119 b that faces the side surface of the image sensor 114. The second surface 119 b of the heat conducting member 119 is in contact with the heat sink 21 provided on the bottom surface 121 of the camera body 11. Here, the heat conducting member 119 and the heat radiating plate 21 constitute a heat conducting means. Reference numeral 116 denotes a liquid crystal display element provided on the back surface of the camera body 11, 118 is a main CPU, and 117 is a main board on which the main CPU is mounted.

  A part of the heat radiating plate 21 is exposed from the bottom surface 121 of the camera body 11 and radiates heat from the heat conducting member 119. The bottom surface 121 of the camera is not provided with an operation member or a display member, and since the surface area is large, the heat radiating plate 21 can be enlarged, and efficient heat dissipation can be performed.

  An image sensor cooling device 123 is attached to the camera bottom surface 121. The image pickup device cooling device 123 can be attached to and detached from the screw hole portion 11a of the camera body 11 with a screw 123d, and is attached to the camera body 11 when necessary, and is usually removed to make the camera body 11 portable. It is increasing.

  The imaging element cooling device 123 includes an electronic cooling element 123a such as a Peltier element, a heat radiating fin 123b, a battery 123c as a power source, the above-described screw 123d, and a temperature detection unit 123e that detects the temperature inside the imaging device. Furthermore, a cooling control unit 123f that performs drive control of the electronic cooling element 123a is provided.

  Here, in the first embodiment, the temperature detection unit 123e is exposed to the outside from the image sensor cooling device 123. When the image sensor cooling device 123 is mounted on the camera body 11, the tip of the temperature detection unit 123 e is inserted into the camera body 11 and comes into contact with the heat conduction member 119 described above.

  The exterior part 123g of the image sensor cooling device 123 is a holding part that holds the temperature detection part 123e so as to have the layout described above. Therefore, the image sensor cooling device 123 can detect the heat generation temperature of the image sensor 114 via the heat conducting member 119, and based on the result, the cooling control unit 123f drives the electronic cooling element 123a as described later. Control. Therefore, the image sensor 114 can always be kept at an appropriate temperature.

  The noise generated by the image sensor 114 decreases as the temperature decreases, but if the temperature is too low, there is a possibility of causing problems such as condensation. Therefore, it is necessary to control the cooling temperature.

  A method of providing a temperature detection unit 123e in the camera body 11 and transmitting the result to the image sensor cooling device 123 to control the driving of the electronic cooling element 123a is also conceivable. However, in that case, a signal transmission unit for transmitting the output signal of the temperature detection unit 123e to the image sensor cooling device 123 is required inside the camera body 11. As described above, the image sensor cooling device 123 is detachably connected to the camera body 11, and in order to exchange signals with each other, it is not only necessary to prepare a plurality of reliable contact terminals, but also exchange of signals. This makes the device complicated for the control.

  Therefore, in the first embodiment, a small and lightweight imaging device cooling device 123 is realized by omitting exchange of signals with the camera body 11 while performing cooling control of the imaging device 114.

  FIG. 2 is a block diagram illustrating the relationship between the electronic cooling element 123a, the temperature detection unit 123e, and the cooling control unit 123f that controls the driving of the electronic cooling element 123a. The temperature signal inside the camera body 11 by the temperature detection unit 123e is compared with the reference temperature 123h by the comparison unit 123i, and the difference signal is input to the cooling control unit 123f. The cooling control unit 123f includes a circuit unit that drives the electronic cooling element 123a. When the difference signal is large (when the temperature of the image sensor 114 is higher than a specified value), a known feedback circuit is configured to increase the cooling capacity (drive power) of the electronic cooling element 123a according to the difference. Yes.

  When a main power switch (not shown) of the imaging element cooling device 123 is operated, electric power is supplied from the battery 123c to the electronic cooling element 123a, the temperature detection unit 123e, and the cooling control unit 123f. Then, the electronic cooling element 123a can be driven and controlled. As described with reference to FIG. 2, the cooling of the electronic cooling element 123a is performed according to the comparison result between the temperature signal detected by the temperature detection unit 123e and the reference temperature 123h. You will control your ability. When the main power switch is on, a display lamp (not shown) provided on the exterior portion 123g is lit to indicate that the main power is on.

  Thus, since the drive control of the electronic cooling element 123a is performed with a simple analog circuit, the imaging element cooling device 123 can be realized in a compact and inexpensive manner.

  According to the first embodiment, the imaging device cooling device 123 is provided in the imaging device by performing drive control of the electronic cooling element 123a such as a Peltier device based on the output of the temperature detection unit 123e that detects the temperature of the imaging device. It is assumed that cooling control of the image sensor 114 is performed. The noise of the image sensor 114 is suppressed. In addition, the imaging device cooling device 123 has a structure that can be attached to and detached from the bottom surface of the imaging device to achieve a reduction in the thickness of the imaging device.

  Specifically, the image sensor cooling device 123 has an attachment / detachment portion (screw 123d) for attaching / detaching the image sensor cooling device 123 to the bottom surface (bottom surface 121) of the image pickup device (camera body 11) including the image sensor 114. Further, when mounted on the imaging device, a temperature detection unit 123e that is held by a holding unit (exterior portion 123g) so as to come into contact with the imaging device (heat radiating plate 21) and detects the temperature of the imaging device is provided. Have. Furthermore, it has the heat sink 21 and the electronic cooling element 123a which are the cooling means which cools the image pick-up element 114. FIG. Furthermore, it has a cooling control unit 123f that is a cooling control unit that performs drive control of the electronic cooling element 123a based on the output of the temperature detection unit 123e, that is, performs drive control so that the temperature of the imaging device does not exceed a specified value.

  Therefore, an imaging device that is thin and has a high cooling effect can be realized. Further, with such a configuration, it is possible to obtain an imaging device that does not hinder the placement of a large liquid crystal monitor on the back surface.

  FIG. 3 is a side sectional view showing the configuration of the image pickup apparatus according to Embodiment 2 of the present invention. Members having the same functions as those in FIG.

  The difference from the first embodiment is that the tip of the temperature detection unit 123e is not inserted into the camera body 11 and is in contact with the camera bottom surface 121. The camera body 11 is not provided with a special mechanism, and the temperature detection unit 123 e detects heat from the image sensor 114 on the bottom surface 121 through the exterior of the camera body 11. Depending on the type of camera, the exterior (housing) is made of a metal such as magnesium and has a structure with high heat conduction.

  The cooling control unit 123f performs drive control of the electronic cooling element 123a based on the temperature signal from the temperature detection unit 123e via the camera bottom surface 121 and the exterior of the camera body 11, and performs cooling control of the imaging element 114.

  With such a configuration, since it is not necessary to provide a special mechanism on the camera body 11 side, the imaging element cooling device 123 that can be mounted on various imaging devices can be realized.

  According to the second embodiment, as in the first embodiment, the driving control of the electronic cooling element 123a is performed based on the output of the temperature detection unit 123e that detects the temperature of the imaging device, and the imaging control for cooling the imaging element 114 is performed. The element cooling device 123 is used. The noise of the image sensor 114 is suppressed. In addition, the imaging device cooling device 123 has a structure that can be attached to and detached from the bottom surface side of the imaging device, for example, to achieve a thin camera.

  Specifically, the image sensor cooling device 123 has an attachment / detachment portion (screw 123d) for attaching / detaching the image sensor cooling device 123 to the bottom surface (bottom surface 121) of the image pickup device (camera body 11) including the image sensor 114. Furthermore, a temperature detection unit 123e, which is a temperature detection unit that detects the temperature of the imaging device, is held by the holding unit (exterior portion 123g) of the imaging device so as to be inserted into the imaging device when mounted on the imaging device. Have. Furthermore, the heat sink 21 and the electronic cooling element 123a, which are cooling means for cooling the imaging element 114, and the cooling control unit 123f, which is a cooling control means for driving and controlling the electronic cooling element 123a based on the output of the temperature detection unit 123e, Have

  With the configuration as described above, it is possible to realize a thin imaging device with a high cooling effect. Further, with such a configuration, it is possible to obtain an imaging device that does not hinder the placement of a large liquid crystal monitor on the back surface.

  4 is a side sectional view of an image pickup apparatus according to Embodiment 3 of the present invention. The same components as those in FIGS. 1 and 3 are denoted by the same reference numerals, and the description thereof is omitted.

  As in the first and second embodiments, in a system in which communication is not performed between the detachable image sensor cooling device 123 and the camera body 11, cooling of the image sensor 114 is controlled on the image sensor cooler 123 side. Is. It is assumed that the electronic cooling element 123a of the imaging element cooling device 123 is always driven by the cooling control unit 123f with constant power.

  In FIG. 4, the heat conducting member 119 such as a graphite sheet provided on the back surface of the image sensor 114 is urged by the tension coil spring 22 and is in contact with the heat radiating plate 21. For this reason, when the imaging element 114 is at a specified temperature or higher, the electronic cooling element 123a is driven and controlled by the cooling control unit 123f, so that the imaging element 114 is cooled via the heat radiating plate 21 and the heat conducting member 119. become.

  Here, the temperature-sensitive spring 23 formed of a shape memory alloy or the like has a characteristic that the heat conductive member 119 contracts when the temperature of the heat conductive member 119 falls below a predetermined temperature. In FIG. 4, the contact with the heat sink 21 is released by pulling upward. For this reason, the image sensor 114 is not further cooled.

  Thus, the part which performs cooling and the part which performs the control are independent. The electronic cooling element 123a of the image pickup device cooling device 123 provided in a detachable manner is always driven by the cooling control unit 123f with constant power, and drive control based on temperature change is not performed. However, since the temperature-sensitive spring 23 controls heat conduction inside the camera body 11 as described above, the image sensor 114 is too cold and the problem of condensation is avoided.

  The image sensor cooling device 123 according to the third embodiment includes the following components in order to obtain the above effects. An attachment / detachment portion (screw 123d) for attaching / detaching the image sensor cooling device 123 to the bottom surface portion (bottom surface 121) of the imaging device (camera body 11) is provided. Further, when mounted on the image pickup apparatus, the heat radiation plate 21 and the electronic cooling element 123a which are cooling means for contacting the heat conduction member 119 of the image pickup apparatus and cooling the image pickup element 114 via the heat conduction member 119 are provided. Have. Furthermore, it has a cooling control unit 123f which is a cooling driving means for driving the electronic cooling element 123a with a constant power.

  In addition, the imaging apparatus includes a heat conducting member 119 that transmits heat generated in the imaging element 114 to the bottom surface portion (bottom surface 121). Furthermore, when the heat generated in the image sensor 114 is lower than the specified temperature, a member (temperature-sensitive spring 23) that changes the position of the heat conduction member 119 is provided so that the bottom surface portion and the heat conduction member 119 do not contact each other. Yes.

  FIG. 5 is a side sectional view of an image pickup apparatus according to Embodiment 4 of the present invention. The same components as those in FIGS. 1, 3, and 4 are denoted by the same reference numerals, and description thereof is omitted.

  In Example 3, the contact control (control of heat conduction) between the cooling means and the heat conducting member is performed by the temperature sensitive spring 23 as shown in FIG. In contrast, in the fourth embodiment, as shown in FIG. 5, a temperature sensor 25 is provided on the back surface of the image sensor 114, and the main CPU 118 is provided with electronic cooling provided in the camera body 11 based on the temperature information detected here. The element 26 is controlled to be cooled.

  The electronic cooling element 26 provided in the camera body 11 is arranged in a direction that prevents heat absorption of the imaging element cooling device 123. That is, when the cooling of the electronic cooling element 26 is controlled, the cooling capability of the imaging element 114 by the imaging element cooling device 123 is reduced.

  As in the case of FIG. 4, the electronic cooling element 123 a of the imaging element cooling device 123 detachably provided is always driven with constant power, and cooling control based on a temperature change is not performed. However, since the electronic cooling element 26 reduces the cooling capacity of the image sensor 114 inside the camera body 11 as described above, the image sensor 114 is overcooled and the problem of condensation is avoided.

  The electronic cooling element 26 mounted on the camera body 11 is small in size, and does not have a sufficient ability to suppress the generated heat of the imaging element 114 and cool it. The battery in the camera body 11 is also small and does not have a sufficient capacity to drive the electronic cooling element 26 and cool the imaging element 114. However, it has a capability of finely controlling the cooling of the imaging device cooling device 123 having a high capability, and the thermal control can be performed more finely than the thermal control of whether or not it makes contact as in the third embodiment.

  In order to obtain the same effect as that of the third embodiment, the image sensor cooling device 123 in the fourth embodiment includes the following components. An attachment / detachment portion (screw 123d) for attaching / detaching the image sensor cooling device 123 to the bottom surface portion (bottom surface 121) of the imaging device (camera body 11) is provided. Furthermore, it has the heat sink 21 and the electronic cooling element 123a which are the cooling means for cooling the image pick-up element 114, when it mounts | wears with an imaging device. Furthermore, it has the cooling control part 123f which is a cooling drive means which drives the electronic cooling element 123a with fixed electric power.

  In addition, the imaging apparatus includes a temperature detection unit (temperature sensor 25) provided in the vicinity of the imaging element 114, and a cooling capacity reduction unit (electronic cooling element 26) that reduces the cooling capacity of the imaging element cooling device 123. Further, when it is detected by the temperature detection means that the temperature of the image sensor 114 is lower than a specified temperature, the electronic cooling element 26 is driven and controlled to reduce the cooling capacity of the image sensor cooling device 123. The main CPU 118 is a cooling capacity control means.

  With the configuration as in the first to fourth embodiments, an imaging device that is thin and has a high cooling effect can be realized, and a captured image with less noise can be obtained in a consumer product.

  Although the description has been continued by taking the digital camera as an example, the apparatus of the present invention is thin and can efficiently cool the image sensor, so that the apparatus is not limited to a digital camera, but a digital video camera, a surveillance camera, a Web camera. It can also be used for mobile phones.

It is side surface sectional drawing which shows the structure of the imaging device which concerns on Example 1 of this invention. It is a block diagram which shows the circuit structure of the cooling control system which concerns on Example 1 of this invention. It is side surface sectional drawing which shows the structure of the imaging device which concerns on Example 2 of this invention. It is side surface sectional drawing which shows the structure of the imaging device which concerns on Example 3 of this invention. It is side surface sectional drawing which shows the structure of the imaging device which concerns on Example 4 of this invention.

Explanation of symbols

11 Camera body 12 Lens barrel 114 Imaging element 118 Main CPU
119 Thermal Conductive Member 121 Bottom 123 Imaging Device Cooling Device 123a Electronic Cooling Element 123d Screw 123e Temperature Detection Unit 123f Cooling Control Unit 123g Exterior Unit 25 Temperature Detection Unit 26 Electronic Cooling Element

Claims (4)

An image sensor cooling device that can be attached to and detached from an image sensor including an image sensor,
An attachment / detachment unit for attaching / detaching the image sensor cooling device to the bottom surface of the image pickup device;
Temperature detecting means for detecting a temperature of the imaging device when the imaging device cooling device is mounted on the imaging device;
Electronic cooling means for cooling the imaging device;
Cooling control means for controlling the driving of the electronic cooling means based on the output of the temperature detection means;
A battery housing for holding electric power to be supplied to the electronic cooling means;
Have a heat radiating plate fin connected to an electronic cooling means,
The heat-radiating plate fin, the battery housing unit, and the cooling control unit are disposed on the opposite side of the imaging element with the electronic cooling unit interposed therebetween, and are disposed in a direction parallel to the bottom surface unit. An image sensor cooling device.   2. The image sensor cooling according to claim 1, wherein the temperature detection unit is held by a holding unit so as to come into contact with the image pickup device when the image pickup device cooling device is attached to the image pickup device. apparatus.   2. The imaging according to claim 1, wherein the temperature detection unit is held by a holding unit so as to be inserted into the imaging device when the imaging device cooling device is mounted on the imaging device. Element cooling device. The said cooling control means performs drive control of the said electronic cooling means based on the output from the said temperature detection means so that the temperature of the said imaging device may not become a regulation value or more. The imaging device cooling device according to any one of the above.

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