JP3606534B2 - Solid-state imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid-state imaging device using a solid-state imaging device such as a CCD, and more particularly to an improvement in a heat dissipation mechanism of a solid-state imaging device.
[0002]
[Prior art]
Conventionally, a solid-state image pickup device such as a CCD increases in dark current in the solid-state image pickup device with an increase in temperature of the solid-state image pickup device during operation. More deteriorated. Therefore, some solid-state imaging devices are provided with a mechanism for cooling the solid-state imaging device. On the other hand, in order to obtain a clearer image, it is necessary to keep the mounting accuracy of each solid-state imaging element in the solid-state imaging device at about 1 μm or less. Therefore, it is necessary to mount the solid-state imaging element and the cooling mechanism in the solid-state imaging device in consideration of the occurrence of mechanical stress during mounting and the influence of dimensional change due to thermal expansion or contraction, which degrades mounting accuracy. is there.
[0003]
Therefore, as a conventional technique, a fixing member having a good thermal conductivity is provided on the back surface of the solid-state image sensor, and the heat is dissipated to the camera casing through the heat conductive member formed by superimposing the metal foil, thereby cooling the solid-state image sensor. There is something that is doing.
[0004]
Hereinafter, the structure of the conventional solid-state imaging device will be described in more detail with reference to FIGS.
In FIG. 3, 1 is a camera casing, 2 is a color separation prism, and the color separation prism 2 separates light incident from an imaging lens (not shown) into light of three primary colors, for example, for each predetermined color component. Each of the decomposed light components is converted into an electric signal by the solid-state imaging device 3 and then synthesized by a processing circuit in the solid-state imaging device to obtain a captured image.
[0005]
A heat conduction chip 21 made of a copper plate is closely attached and fixed to the back surface 3b of the solid state image pickup element 3 in order to absorb heat in the solid state image pickup element 3, and a heat conduction plate 22 is closely attached and fixed to the heat conduction chip 21. ing. In addition, the sensor substrate 4 is disposed behind the heat conducting plate 22 with the insulating plate 23 interposed therebetween. The sensor substrate 4 has a circuit for processing a signal from the solid-state image sensor 3, and a terminal 3a of the solid-state image sensor 3 is fixed by soldering. Further, the first metal fitting 5 fixedly attached to each color component light emission surface of the color separation prism 2 and the second metal fitting 6 fixedly attached to each solid-state imaging device 3 are soldered with solder 7. By attaching, the color separation prism 2 and the image sensor 3 are fixed.
[0006]
On the other hand, each heat conducting plate 22 is closely fixed to the copper foil heat radiating plate 24 by mounting screws 25. In addition, the copper foil heat sink 24 is tightly fixed to the camera housing 1 by mounting screws 26. The copper foil heat sink 24 is formed by laminating a plurality of copper foils, for example, copper foil 24a to copper foil 24f, which are joined and integrated with a thin adhesive and layered, for example, as shown in FIG. The shape is cut and bent by pressing. In order to further improve the flexibility of the copper foil heat sink 24, several slits are provided for each bent portion.
[0007]
With the structure as described above, the heat generated from the imaging device 3 is transmitted to the heat conductive plate 22 via the heat conductive chip 21, and the transmitted heat is a flexible copper foil heat radiating plate 24. Is transmitted to the camera casing 1.
[0008]
[Problems to be solved by the invention]
However, the above prior art has the following problems.
That is, each solid-state imaging device is fixed to the color separation prism after optical three-dimensional position adjustment with respect to the color separation prism. Therefore, as a result of individual adjustment, the positional relationship of the three solid-state imaging elements of the R, G, and B channels is not fixed, and the positional relationship may be shifted in all directions by the solid-state imaging device. There is. As a result, as described above, the relative positions of the screw hole positions of the heat conducting plate 22 that are closely fixed to the back surface of the solid-state imaging device via the heat conducting chip and the corresponding screw hole positions of the heat conducting member 24 are provided. There is a possibility that the amount of deviation becomes larger. In addition, relative displacement of the screw hole positions also occurs due to the accumulated dimensional errors of the members constituting the heat dissipation structure.
[0009]
Therefore, when the copper foil heat sink 24 is screwed to the heat conduction plate 22 and the camera casing 1 with the mounting screws 25 and 26, the displacement amount of each screw hole is large, and the mechanical stress generated thereby is very small. In the case where the mechanical stress must be absorbed by only the flexible copper foil heat radiating plate 24 and the mechanical stress is significantly shifted in one direction, the There is a possibility that the foil heat radiating plate 24 may receive a great deal of stress that cannot be absorbed. In that case, the mounting position of the solid-state imaging device is shifted due to the stress, and the mounting accuracy is deteriorated, thereby causing a registration shift and degrading the image quality to be captured. Further, in this heat radiation path, the portion from the solid-state imaging device 3 to the heat conducting plate 22 is made of a rigid body such as a metal and is fixedly connected to each other. Mechanical stress due to the applied torque is applied to the solid-state imaging device, and registration deviation occurs. In order to prevent the occurrence of registration deviation due to the screw fastening, it is necessary to regulate the tightening torque at the time of the screw fastening described above, which causes deterioration in assemblability and heat transfer efficiency. .
[0010]
It is an object of the present invention to eliminate these drawbacks, to cool a solid-state image sensor efficiently, and to provide a solid-state image sensor cooling structure with good assemblability.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a first heat conductive member capable of absorbing heat from a solid-state imaging device and a highly flexible material formed by overlapping metal foils. The two heat conducting members are respectively disposed on the back surfaces of the solid-state imaging devices of a plurality of color channels, for example, R, G, and B channels. The first heat conducting member and the second heat conducting member attached to the first heat conducting member are attached to the back surface of the solid state image sensing device with a predetermined pressure by the leaf springs attached to the respective solid state image sensing devices. It is made to adhere to.
[0012]
According to the above-described configuration, the heat generated from the solid-state imaging device can be efficiently radiated to the camera housing side to which the second heat conducting member is screwed via the heat conducting member. The mechanical stress caused by the screw hole misalignment at the time of assembly is distributed to each of the R, G, and B channels, and each stress is absorbed by the flexibility of each second heat conducting member. The occurrence of deviation can be suppressed.
[0013]
Further, according to the above-described configuration, the surface where the first heat conducting member and the heat absorbing member are in contact and the surface where the heat absorbing member and the solid-state imaging element are in contact are only in close contact with a predetermined pressure, Even if the second heat conducting member is screwed to the first heat conducting member or the second heat conducting member is screwed to the camera housing side, the screw tightening torque is used. By rubbing these contact surfaces, it is possible to prevent the influence of mechanical stress on the solid-state image sensor due to the screw tightening torque.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS. 1 to 7 in FIG. 1 are the same as those described in the prior art described above, and the description thereof is omitted here.
[0015]
In FIG. 1, a support 8 having a screw portion for attaching a plate spring 14 to be described later is attached to the second metal fitting 6. The heat absorption part of the Peltier cooling element 9 which is a heat absorption member is brought into contact with the back surface 3b of the solid-state imaging element 3 via the heat conductive double-sided adhesive tape 10, and the heat dissipation part of the Peltier cooling element 9 is also thermally conductive. The first heat conducting member 11 made of a metal having high thermal conductivity is brought into contact with the adhesive tape 10.
[0016]
Reference numeral 12 denotes a second heat conducting member which is formed by superposing metal foils having high thermal conductivity and is provided with a bent portion having a slit to increase flexibility. The second heat conducting member 12 is pressed and fixed to the first heat conducting member 11 by means of a mounting screw 18 and a holding plate 13. The presser plate 13 is such that the tightening pressure at the time of tightening those screws is applied to a wider area so that the degree of adhesion becomes higher in the close contact between the first heat conductive member 11 and the second heat conductive member 12. It is provided to make it.
[0017]
Further, 14 is a leaf spring, 15 is an insulating chip attached to the leaf spring 14, and this insulating chip 15 is made of, for example, a flame retardant plastic in order to improve thermal insulation. The plate spring 14 is screwed and fixed to the above-mentioned support column 8 with an attachment screw 19, whereby the direction of the solid-state imaging device 3 attached to the metal fitting 6 with a predetermined pressure through the attached insulating chip 15. In addition, the first heat conducting member 11 is pressed. For this reason, the solid-state imaging element 3 and the Peltier cooling element 9 and the Peltier cooling element 9 and the first heat conducting member 11 are brought into close contact with each other.
[0018]
Each second heat conducting member 12 is pressed and fixed by a mounting screw 20 after a square washer 17 is inserted into each mounting position of the heat radiating plate 16 screwed to the camera housing 1.
[0019]
With the structure described above, the heat generated from the solid-state imaging element 3 is absorbed by the heat absorption side of the Peltier cooling element 9. The absorbed heat is transmitted to the first heat conducting member 11 in close contact with the heat radiating side of the Peltier cooling element 9, and then to the camera housing 1 via the second heat conducting member 12 and the heat radiating plate 16. Heat is dissipated efficiently.
[0020]
At this time, the mechanical stress in each part caused by the temperature change of each member is dispersed by the plurality of second heat conducting members 12 and absorbed by the flexibility of each second heat conducting member. Registration deviation does not occur.
[0021]
In addition, the first heat conducting member 11 to which the second heat conducting member 12 is attached is pressed and adhered to the back surface 3b of the solid-state imaging device 3 of each of the R, G, and B channels with a predetermined pressure. Thus, unlike the structure described in the prior art, the second heat conducting member 12 and the solid-state imaging device 3 are not fixed. Therefore, rubbing can be generated at the contact portion when the screw is tightened, and no mechanical stress is applied to the solid-state imaging device 3, so that it is not necessary to regulate the screw tightening torque, and the assemblability is very good. .
[0022]
In the embodiment shown in FIG. 1, the Peltier cooling element 9 is used as the heat absorbing member. However, when it is not necessary to provide the member, the first heat conducting member 11 is directly applied to the back surface of the solid-state imaging element 3. Even if they are brought into contact with each other, a good heat dissipation effect can be obtained.
[0023]
In order to further cool the solid-state imaging device 3, as shown by phantom lines in FIG. 2, the heat conducting member 11 has a structure that radiates heat not only to the heat radiating plate 16 but also to the heat radiating plate 16 ′. Further cooling effect can be obtained.
[0024]
【The invention's effect】
According to the present invention, by attaching the cooling mechanism to the solid-state imaging device, mechanical stress from the cooling mechanism is prevented from affecting the solid-state imaging device, and registration shift due to the influence occurs. You can avoid it.
[0025]
In addition, it is possible to realize a solid-state imaging device with a simple shape of the heat conductive material and good workability.
Furthermore, since the mechanical stress at the time of screw tightening can be eliminated by the fact that the contact is caused by rubbing at the predetermined pressure, there is no need for screw tightening torque regulation, and therefore the assembly is improved. The cost of the solid-state imaging device can be reduced.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a part of a solid-state imaging device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a part of a solid-state imaging device according to an embodiment of the present invention.
FIG. 3 is an exploded perspective view of a part of a conventional solid-state imaging device.
FIG. 4 is a cross-sectional view of a part of a conventional solid-state imaging device.
FIG. 5 is a diagram for explaining a state of overlapping of copper foils on a copper foil heat sink 24 formed by overlapping copper foils.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Camera housing, 2 Color separation prism, 3 Solid-state image sensor, 9 Peltier cooling element, 10 Thermal conductive double-sided adhesive tape, 11 1st heat conductive member, 12 2nd heat conductive member, 13 Presser plate, 14 plate Spring, 15 Insulating chip, 16 Heat sink, 17 Square washer, 18-20 Mounting screw.

Claims (3)

In a solid-state imaging device that performs color imaging using a solid-state imaging device fixed to each color component light emission surface of a color separation prism that separates light incident on the imaging device into predetermined color components,
A heat-absorbing member disposed in contact with the back surface of each solid-state imaging device; a first heat-conducting member disposed in contact with another surface opposite to the contact surface of each heat-absorbing member; A flexible second heat conductive member fixed to the first heat conductive member, and a leaf spring that pressurizes each first heat conductive member, and each leaf spring is at a predetermined pressure. Thus, the first heat conducting member is pressed against the respective solid-state imaging device, and the solid-state imaging device, the heat absorbing member, and the first heat conducting member are in close contact with each other. Imaging device. The solid-state imaging device according to claim 1,
The heat absorbing member disposed between each solid-state image sensor and the first heat conducting member is a Peltier cooling element, and each Peltier cooling element absorbs heat from the solid-state image sensor, and the first A solid-state imaging device which is operated to dissipate heat to the heat conducting member. The solid-state imaging device according to claim 1,
The second heat conducting member has a bent portion, and each of the bent portions is provided with a slit.

Images