JP2007104573A - Cooling imaging unit and imaging apparatus mounting the imaging cooling unit therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein heat is conducted from a dissipation surface of a Peltier element that cools an imaging element to a base, but when heat dissipation property of the base is adverse, heat is accumulated from a point of time when the heat can not be suppressed by heat dissipation, the temperature of an entire package is elevated, the temperature of a camera mounted therein is also elevated, and image quality of a picked-up image is degraded. <P>SOLUTION: The present invention provides a cooling imaging unit configured to thermally connect an imaging element held by a frame part comprised of a heat insulated resin material to a base part constructed from a material of high heat dissipation property to which black anodized aluminum treatment is applied, while absorbing dimensional variation by holding a fixing member and a Peltier element therebetween and interposing an elastic member between the base part and the frame part. The present invention relates to an imaging apparatus which picks up a high-quality image from which adverse influence caused by heating of the imaging element is excluded, by mounting and cooling the cooling imaging unit, and by driving the imaging element on proper operational conditions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus equipped with a cooling unit for cooling a semiconductor imaging element.

  2. Description of the Related Art Generally, an electronic image pickup apparatus, a so-called digital camera, on which an image sensor (for example, a charge coupled device CCD: Charge Coupled Device) composed of a semiconductor image pickup element is mounted is widespread. Since this digital camera does not require film development or printing processing in a film camera, it is possible to confirm a photographed image immediately after photographing, to process an image with a personal computer or the like, and to communicate as an electric signal. It has advantages and is used in a wide range of fields. This digital camera forms an optical image on a light receiving surface of an image sensor by a photographing lens optical system, converts it into an electrical signal by photoelectric conversion, and then performs A / D conversion processing to obtain digital image data (hereinafter referred to as image data). It is obtained as The image output is displayed on a liquid crystal screen provided in the camera body, printed by a printer, or displayed on an external display device such as a personal computer.

  This image sensor can be driven optimally within the environmental range defined in the design specifications, and a high-quality image can be obtained. However, actually, the drive characteristics of the image sensor are affected by heat (air temperature, etc.) due to the external environment or heat generated during driving, which adversely affects the image quality of the captured image.

Therefore, in order to prevent deterioration of image quality due to heat, a technique for cooling the image sensor to an appropriate operating temperature is incorporated. As the cooling means, for example, a Peltier element that is small in size and free of vibration and noise and can be accurately controlled in temperature is attached to the imaging element. The technique proposed in Patent Document 1 is one of the techniques. This technology relates to a digital camera equipped with an image pickup device in which a cooling mechanism is provided in a package constituting a head unit. That is, a configuration is disclosed in which both the imaging element and the Peltier element that cools the imaging element are accommodated in a package (base) provided with a cap and a protrusion. In this configuration, the Peltier element is connected to the protrusion so as to be able to conduct heat. With such a configuration, even if the amount of heat released from the Peltier element increases rapidly, the protrusions absorb the increased amount and perform thermal radiation to prevent a rapid increase in temperature with respect to the imaging element.
JP 2003-258221 A

In Patent Document 1 described above, the heat dissipation surface of the Peltier element is in contact with the protrusion of the base made of copper, and heat from the heat dissipation surface of the Peltier element is conducted to the base.
In general, copper has a high thermal conductivity but has a low thermal emissivity. Therefore, when the Peltier element is driven, the heat generated from the Peltier heat dissipation surface is once absorbed by the base, but if the heat of the base itself is poor, the absorbed heat may gradually accumulate in the base. .

  Therefore, when the image sensor is cooled to a desired temperature, the more the temperature difference is, the more heat is conducted from the heat dissipation surface of the Peltier element to the base. To go. As the temperature rises, the temperature of the metal cap connected to the base also increases, and as a result, the temperature of the entire package increases.

  Therefore, when such a package is mounted on a digital camera, when the image sensor is cooled, the temperature of the camera body may be increased as the temperature of the package increases. There is a possibility of causing trouble in the camera operation due to the temperature rise of the camera body. In order to prevent such a temperature rise, it is necessary to provide a restriction on the cooling of the image sensor even if the image quality is assumed to deteriorate.

  Furthermore, in consideration of the fact that the temperature of the entire package has risen beyond the heat dissipation capability, if the inside of the package is in a vacuum insulation state, the heat in the base and the cap does not enter the image sensor, and the image sensor can be efficiently cooled. However, a special facility is required to manufacture the vacuum package, which requires a lot of man-hours. Further, it is necessary to provide the package with a sealing structure for maintaining a vacuum state, which increases the unit cost of the package and the manufacturing cost of the camera.

  Therefore, the present invention has an object to provide a cooling imaging unit having a structure in which the imaging element is efficiently cooled and the cooling element for cooling the imaging element has a high heat dissipation property, and an imaging apparatus equipped with the imaging cooling unit. And

  In order to achieve the above-mentioned object, the present invention achieves the above-described object by generating an image signal by photoelectric conversion from a light image incident on the imaging surface, and thermally connecting an endothermic surface to the imaging device and cooling to a predetermined temperature. The Peltier element is formed by a Peltier element having heat dissipation, a base portion having a film thermally connected to a heat dissipation surface side of the Peltier element and assisting heat radiation, and a member having heat insulation properties. A frame portion that is mounted in an airtight manner on the base portion, and that is configured to hold the heat generated by the image pickup device. There is provided a cooled imaging unit that prevents the heat radiated from the base part from being radiated from the base part to the imaging element and the Peltier element.

  Furthermore, an image pickup device that generates an image signal by photoelectric conversion from a light image incident on the image pickup surface, a Peltier device that thermally connects a heat absorption surface to the image pickup device and cools it to a predetermined temperature, and has heat dissipation. The imaging that is formed by a base portion having a film thermally connected to the heat dissipation surface of the Peltier element and assisting heat radiation, and a member having a heat insulating property so that a light image can be incident on the imaging surface. A cooling image pickup unit configured by a frame portion that houses an element and the Peltier device and is hermetically attached to the base portion, and a function that accommodates the cooling image pickup unit and adjusts the attachment position of the image pickup device inside There is provided an imaging apparatus comprising: a fixing unit having a window; and an apparatus housing including a window that allows an optical image to enter the imaging element and can be attached to an observation port.

  According to the present invention, it is possible to provide a cooling image pickup unit having a structure in which an image pickup element is efficiently cooled and a cooling element for cooling the image pickup element has a high heat dissipation property, and an image pickup apparatus including the image pickup cooling unit. it can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a configuration example of a cooling imaging unit according to the first embodiment of the present invention.
The cooling imaging unit 1 includes a flat base portion 2, a cap-shaped frame portion 3a fixed to the base portion 2 via a gasket 4, and a window 3b opened at the bottom of the frame portion 3. The light transmitting member 5 to be fitted, the imaging circuit board 6 fixed to the convex part 3 c inside the frame part 3, the imaging element 7 which is an image sensor mounted on the imaging circuit board 6, and the bottom side of the imaging element 7 The fixing member 8 is made of a metal that is thermally connected to, that is, in close contact with, and has high thermal conductivity, and the Peltier element 9 that has the heat absorbing surface 9a in close contact with the fixing member 8 and the heat radiating surface 9b in close contact with the base portion 2. Is done.

  The image sensor 7 is a semiconductor image sensor, and for example, a CCD image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor is suitable. Further, the image pickup device 7, the fixing member 8 and the Peltier device 9 are integrally stacked and fixed to the base portion 2, so that heat generated by the image pickup device 7 can be efficiently conducted to the base portion 2. Are in close contact with each other. At the time of actual attachment, adhesion may be enhanced by using an adhesion material such as thermally conductive silicon grease on both surfaces of the fixing member 8 and the Peltier element 9.

  The base portion 2 is formed of a metal having high thermal conductivity such as aluminum, and is subjected to black alumite treatment except for a partial surface region 2a facing the frame portion 3 attached to the surface. The surface treatment of the base portion 2 has been described with an example of black alumite, but is not limited to alumite, and may be a coating treatment having a high thermal emissivity, such as plating / chromate treatment.

  The frame portion 3 is formed in a cap shape with a flange portion 3a from a resin material such as acrylic. In the center of the bottom surface of the frame portion 3, a window 3 b for imaging with an imaging element is opened. A light transmissive member 5 made of a transparent material that can transmit light, such as glass or transparent resin, is fitted in the window 3b, and is fixed so as to be airtight with an adhesive or the like. In addition, a plurality of protruding protrusions 3 c are formed on the inner bottom surface of the frame 3. As long as the imaging circuit board 6 is attached with high attachment position accuracy, the convex portion 3c may have a plurality of columnar shapes, or may be connected linear or annular. The method of attaching the imaging circuit board 6 may be screwing, a configuration in which irregularities are formed on each side and fitted and fixed, or may be bonded and fixed with an adhesive or the like. The gasket 4 is an O-ring formed of an elastic material such as rubber or resin.

  When the image pickup device 7 is mounted on the image pickup circuit board 6 provided with the element driving circuit and the signal processing circuit, the respective terminals are electrically connected, and the image pickup circuit board 6 is attached to the convex portion 3 c of the frame portion 3. In addition, the light receiving surface is opposed to the window 3b and is disposed at a position where a light image transmitted through the light transmitting member 5 can be received. The fixing member 8 and the base portion 2 are preferably made of a metal having high thermal conductivity, and for example, aluminum, copper, or iron is used.

In such a configuration, when the Peltier device 9 cools the imaging device 7, heat from the heat radiation surface 9 b is absorbed by the base portion 2. According to the thermal property data of the metal material, when aluminum is used as the material, the normal thermal emissivity is about 0.05. However, when the surface of the base portion 2 is subjected to black alumite treatment, the thermal emissivity is Increases to 0.95.
Accordingly, since the base portion 2 is subjected to black alumite treatment except for the partial surface region 2a facing the inner side of the frame portion 3, the thermal emissivity is increased like a radiating fin and absorbed from the image pickup device 7. Heat can be radiated efficiently to the outside.

  Therefore, even if the base part 2 absorbs the heat from the heat radiating surface 9b side of the Peltier element 9, the heat is not accumulated, and the temperature rise can be suppressed low. Moreover, since the frame part 3 is formed of a resin material having a low thermal conductivity, for example, an acrylic material, it has a heat insulating effect from the outside. Further, by arranging a 0 ring between the base portion 2 and the frame portion 3, it is possible to absorb variations in manufacturing dimensions (an error in the height direction) when the imaging device 7, the fixing member and the Peltier device 9 are brought into close contact with each other. The frame portion 3 can be fixed in close contact with the base portion 2 without a gap. Thereby, it is possible to prevent the heat radiated from the base portion 2 from flowing into the imaging element 7 and the Peltier element 9.

  In FIG. 1, a configuration in which the fixing member 8 is interposed between the imaging element 7 and the Peltier element 9 is shown as an example. However, the fixing member 8 is not necessarily interposed, and the imaging element 7 and the Peltier element are not necessarily provided. 9 may be directly connected thermally, that is, in close contact.

  From the above, according to the cooling imaging unit of the present embodiment, the heat dissipation of the base portion is improved by the black alumite treatment applied to the surface of the base portion except for the partial surface region facing the inside of the frame portion. As a result, the temperature rise of the base unit and the entire unit can be suppressed when the image sensor is cooled. Furthermore, since the frame portion is formed using a heat-insulating acrylic material and the frame portion is attached using an O-ring, the gap between the base portion and the frame portion is eliminated, and the image sensor and the Peltier element are connected. The wraparound of the heat radiated to the outside by the base portion can be prevented, and the image sensor can be efficiently cooled.

Furthermore, a modified example of the first embodiment will be described.
In the modification shown in FIG. 2, in addition to the configuration of the cooling imaging unit of the first embodiment, the resin plate 11 is laid so as to be in close contact with the partial surface region 2 a of the base portion 2. By using the heat insulating property of the resin plate 11, it is possible to suppress heat from being radiated into the frame portion 3 from the partial surface region 2 a of the base portion 2 whose temperature is increased by the heat conducted from the imaging element 7. The image sensor can be efficiently cooled.

Next, a second embodiment will be described.
FIG. 3 shows a configuration example of an imaging apparatus equipped with a cooling imaging unit according to the second embodiment. In the configuration of the present embodiment, the same reference numerals are assigned to the same components as those shown in FIG. 1 described above, and detailed description thereof is omitted. The imaging device of this embodiment is configured to be attached to a camera port of an eyepiece tube in an observation device such as a microscope. Therefore, the photographing lens optical system of a general digital camera is not provided.

  In this imaging apparatus, the cooling imaging unit 1 of the first embodiment described above is mounted inside a box-shaped apparatus housing 21 provided with a window 24 for allowing an optical image to enter. This window has a configuration that can be attached to the camera port of the eyepiece tube in the observation apparatus. For example, a fitting portion such as a mounting adapter (not shown) is provided. A fixing portion 21a projecting inward is provided in the apparatus housing 21, and a plurality of fixing screw holes 21b are opened and fixed with screws 22 or the like.

  In the present embodiment, the base portion 2 in the cooling imaging unit 1 described above is extended to open a plurality of fixing holes 2c. These fixing holes 2c are opened at positions that overlap with the fixing screw holes 21b when the cooling imaging unit 1 is placed on the fixing portion 21a. In particular, when the apparatus housing 21 is attached to the camera port, the optical axis of the observation optical system in the observation apparatus (center position of the observation visual field) and the center position of the light receiving surface of the imaging element of the cooling imaging unit 1 (of the captured image). Centering adjustment must be performed so that the center position matches. For this centering adjustment, the fixing hole 2c is formed as a position adjusting hole so that the cooling imaging unit 1 can be moved two-dimensionally with respect to a plane orthogonal to the optical axis. Further, by interposing the spacer 23 between the fixed portion 21a and the base portion 2, the front-rear position adjustment and the angle adjustment of the cooling imaging unit 1 in the optical axis direction can be performed with respect to the apparatus housing 21.

  According to the imaging apparatus configured as described above, the heat generated when the imaging element 7 is driven is conducted from the heat radiation surface 9 b of the Peltier element 9 to the base portion 2. Since the base part 2 efficiently radiates heat, the temperature rise of the base part 2 itself is reduced, and the amount of heat conducted from the base part 2 to the apparatus housing 21 is reduced. Further, since the device housing 21 has a certain surface area, the heat conducted from the base portion 2 is radiated to the outer space through the device housing 21. In addition, since the frame portion 3 is formed of a resin material, there is a heat insulating effect, and even when the temperature of the cooling imaging unit 1 rises, heat does not go around the Peltier element 9.

  From the above, the image pickup apparatus equipped with the cooling image pickup unit of the present invention can efficiently transfer the heat generated by the image pickup element to the base portion using the Peltier element. Also in the base portion, the heat radiation is improved by the black alumite treatment, and the temperature rise of the base portion can be suppressed when the image sensor is cooled, and as a result, the temperature rise of the entire unit can be suppressed. Furthermore, heat is conducted from the base unit to the device housing of the image pickup device, the temperature rise of the base unit is suppressed, the image pickup device can be driven under suitable operating conditions by being efficiently cooled, and a high-quality shot image can be obtained. Obtainable.

It is sectional drawing which shows the structural example of the cooling imaging unit which concerns on 1st Embodiment by this invention. It is sectional drawing which shows the structural example of the cooling imaging unit used as the modification of 1st Embodiment. It is sectional drawing which shows the structural example of the imaging device which mounts the cooling imaging unit which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cooling imaging unit, 2 ... Base part, 3 ... Frame part, 3a ... Gutter part, 3b ... Window, 3c ... Projection part, 4 ... Gasket, 5 ... Light transmission member, 6 ... Imaging circuit board, 7 ... Semiconductor imaging Element (imaging element), 8 ... fixing member, 9 ... Peltier element, 9a ... heat absorption surface, 9b ... heat radiation surface, 11 ... resin plate.

Claims (5)

An image sensor that generates an image signal by photoelectric conversion from a light image incident on the imaging surface;
A Peltier element that thermally connects an endothermic surface to the imaging element and cools it to a predetermined temperature;
A base portion having a heat dissipation property, thermally connected to the heat dissipation surface side of the Peltier element, and having a film for assisting thermal radiation;
A frame portion that is formed of a member having heat insulation properties, and that houses the imaging element and the Peltier element that hold an optical image so as to be incident on the imaging surface, and is hermetically attached to the base portion;
Comprising
The heat generated by the imaging device is conducted to the base portion and radiated, and the frame portion prevents the heat radiated from the base portion from wrapping around the imaging device and the Peltier element. Cooling imaging unit.   The cooling imaging unit according to claim 1, wherein a fixing member made of a metal having thermal conductivity is interposed between the heat absorption surfaces of the imaging element and the Peltier element. An elastic member interposed in an attachment portion between the base portion and the frame portion;
2. The elastic member according to claim 1, wherein the elastic member is received so as to ensure airtightness with outside air and to eliminate a dimensional error when the imaging element and the Peltier element are integrally stacked. Cooling imaging unit.   The base part is made of metal, and the coating coated on the surface of the base part is a heat formed by black alumite treatment on the entire surface excluding the surface of the base part in contact with the inner surface of the frame part to be attached. The cooling imaging unit according to claim 1, wherein the cooling imaging unit is a film that assists radiation. An image sensor that generates an image signal by photoelectric conversion from a light image incident on the imaging surface;
A Peltier element that thermally connects an endothermic surface to the imaging element and cools it to a predetermined temperature;
A base portion having a heat dissipation property and having a film thermally connected to the heat dissipation surface of the Peltier element and assisting heat radiation; and
A cooling imaging unit that is formed of a member having heat insulation properties and includes a frame portion that houses the imaging element and the Peltier element that hold an optical image so as to be incident on the imaging surface, and is airtightly attached to the base portion. When,
An apparatus housing having a cooling unit that houses the cooling imaging unit and that has a function capable of adjusting the mounting position of the imaging device inside, and a window that allows a light image to enter the imaging device and can be attached to an observation port When,
An imaging apparatus comprising:

Images