JP2009224957A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow an imaging device to be cooled down to a lower temperature. <P>SOLUTION: In an imaging apparatus 11, the imaging device 23 and a cooling element 24 are arranged in the front space 32 surrounded by an outer enclosure 21, an optical filter 29, and a chamber wall 25. A rear space 33 surrounded by the outer enclosure 21, the chamber wall 25, and a chamber wall 30, is provided adjacently to the front space 32. A dehumidifier 34 dehumidifies the front space 32, and the resulting steam is discharged to the rear space 33. A dehumidifier 35 dehumidifies the rear space 33. A dehumidification effect of the front space 32 is enhanced by dehumidifying the rear space 33. As a result, the imaging device 23 is cooled up to a lower temperature by the cooling element 24. This invention is applicable to an imaging apparatus. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device that can cool an imaging device to a lower temperature.

  In imaging devices with built-in image sensors such as CCD (Charge Coupled Devices) and CMOS (Complementary Metal Oxide Semiconductor), it is known that the image quality deteriorates due to the increase in dark current noise accompanying the temperature rise of the image sensor. Yes. Therefore, the image pickup apparatus is provided with an electronic cooling element such as a Peltier element that cools the image pickup element in order to prevent deterioration of the image quality.

  However, when the image sensor is cooled by the electronic cooling element, there is a case where condensation occurs around the image sensor or the electronic cooling element and the subject cannot be imaged. In view of this, there has been proposed an imaging apparatus that is provided with a dehumidifying element that dehumidifies the space inside the housing in which the imaging device and the electronic cooling element are arranged, and prevents the occurrence of condensation by keeping the space inside the housing in a low humidity state. (For example, refer to Patent Document 1).

JP 2006-246315 A

  By the way, in an imaging device, in order to cool the imaging device to a lower temperature without causing condensation, the dehumidifying effect is achieved by using the space inside the housing of the imaging device as an airtight chamber to increase the dehumidifying efficiency or by providing a large dehumidifying element. It is necessary to keep the space inside the housing in a lower humidity state.

  However, in order to make the space inside the housing an airtight chamber, it is necessary to weld the housing or seal an opening for passing a cable connected to a substrate in the housing. Not only will it cost, but it will also be expensive. In addition, when the dehumidifying element provided in the image pickup apparatus is large, the layout of each member provided in the image pickup apparatus is limited or the housing has to be enlarged, which makes it difficult to reduce the size of the image pickup apparatus.

  The present invention has been made in view of such a situation, and allows an image sensor to be cooled to a lower temperature more easily.

  An imaging apparatus according to the present invention includes a first space and a second space that are adjacent to each other and are surrounded by a housing, an imaging device that is disposed in the first space and images a subject, Moisture that is disposed in the first space and that cools the image sensor and a dehumidifying part that absorbs moisture in the first space are exposed to the first space and dehumidified by the dehumidifying part. A first dehumidifying element configured to dehumidify the first space, and a dehumidifying unit configured to absorb moisture in the second space, the first dehumidifying element disposed to be exposed to the second space. The second space, which is disposed in such a manner that a discharge portion that is exposed to the second space and releases moisture dehumidified by the dehumidifying portion of the first dehumidifying element is exposed to the outside of the housing. And a second dehumidifying element for dehumidifying.

  According to the present invention, it is possible to more easily suppress the occurrence of condensation and cool the imaging device to a lower temperature.

  Embodiments to which the present invention is applied will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration example of an embodiment of an imaging apparatus to which the present invention is applied.

  A control board 22 made of a printed wiring board or the like provided in the image pickup apparatus 11 is fixed to the external housing 21 of the image pickup apparatus 11 by screws (not shown). An image sensor 23 made of CMOS or the like is disposed. Further, a through hole is provided in the center of the control board 22, and a cooling element 24 made of a Peltier element or the like is disposed in the through hole.

  Inside the outer casing 21, a protruding portion that protrudes inside the outer casing 21 and that locks the chamber wall 25 is provided. The chamber wall 25 is provided with a screw 26 and a screw 27 so as to protrude from the outer casing 21. It is fixed with screws. Further, a groove is provided in a portion of the projecting portion of the external housing 21 that comes into contact with the chamber wall 25, and an O-ring 28 is fitted into the groove. The O-ring 28 maintains the airtightness of the space surrounded by the outer casing 21 and the chamber wall 25.

  In the present invention, since it is not always necessary to maintain high airtightness, the O-ring 28 is not essential.

  The chamber wall 25 functions as a heat radiating casing, and transfers heat generated from the cooling element 24 disposed between the imaging element 23 and the chamber wall 25 to the external casing 21 via the chamber wall 25. In addition, a through hole for allowing light from the subject to enter the light receiving surface of the image sensor 23 is provided in a portion of the external housing 21 facing the light receiving surface of the image sensor 23 so as to cover the through hole. In addition, a plate-like optical filter 29 is fixed to the external housing 21.

  Furthermore, the space inside the outer casing 21 is covered with a chamber wall 30 to be an airtight chamber. In other words, the chamber wall 30 is fixed to the outer casing 21 with a screw or the like (not shown) so that the chamber wall 25 and the chamber wall 30 face the outer casing 21. In addition, a groove is provided in a portion of the outer casing 21 that contacts the chamber wall 30, and an O-ring 31 is inserted into the groove. The O-ring 31 maintains high airtightness inside the external housing 21.

  As described above, in the imaging device 11, one space inside the imaging device 11 is formed by being surrounded by the external housing 21, the optical filter 29, and the chamber wall 30, and the space is partitioned by the chamber wall 25 and adjacent to each other. It is divided into two spaces. In other words, the imaging device 11 is surrounded by the front space 32 formed by being surrounded by the outer casing 21, the optical filter 29, and the chamber wall 25, and the outer casing 21, the chamber wall 25, and the chamber wall 30. A rear space 33 is formed.

  In the front space 32, a control board 22, an image sensor 23, and a cooling element 24 are arranged. Wiring and the like are arranged in the rear space 33. Further, the volume of the rear space 33 is made smaller than the volume of the front space 32.

  Further, the chamber wall 25 is provided with a dehumidifying element 34 for dehumidifying the interior of the front space 32, and the chamber wall 30 is provided with a dehumidifying element 35 for dehumidifying the interior of the rear space 33. The dehumidifying element 34 and the dehumidifying element 35 are arranged so as to face each other and to be positioned substantially on a straight line.

  The dehumidifying element 34 and the dehumidifying element 35 are constituted by an electrolysis cell made of a solid polymer electrolyte membrane provided with, for example, an anode and a cathode. Here, the dehumidifying element 34 is fixed to the chamber wall 25 so that the anode is exposed to the front space 32 and the cathode is exposed to the rear space 33, and the dehumidifying element 35 is exposed to the rear space 33, Is fixed to the chamber wall 30 so as to be exposed to the outside of the imaging device 11. As described above, the cathode of the dehumidifying element 34 and the anode of the dehumidifying element 35 are provided to face each other and close to each other.

  The dehumidifying element of the present invention has a dehumidifying part on one side in one dehumidifying element, and an emitting part on the other side that dehumidifies in this dehumidifying part and positively releases the moisture held by the dehumidifying element. It is essential.

  Next, the operation of the imaging device 11 will be described.

  Light from the subject enters the light receiving surface of the image sensor 23 via the optical filter 29. At this time, the light from the subject is incident on the image sensor 23 after a predetermined wavelength component is removed by the optical filter 29. The image sensor 23 captures an image of a subject by receiving the light incident from the optical filter 29 and performing photoelectric conversion. The acquired image is supplied to and recorded in a memory (not shown) provided on the control board 22, for example.

  In addition, the cooling element 24 cools the imaging element 23 during imaging of the subject. In other words, the cooling element 24 transmits the heat generated in the imaging element 23 to the external housing 21 through the chamber wall 25. As a result, the image sensor 23 is cooled and the occurrence of dark current noise is suppressed, so that the image quality of the subject image can be improved.

  Further, when the subject is imaged, the dehumidifying element 34 dehumidifies the interior of the front space 32, and the dehumidifying element 35 dehumidifies the interior of the rear space 33. That is, when the dehumidifying element 34 is supplied with electric power from a power source (not shown), moisture (water) is electrolyzed in the vicinity of the anode of the dehumidifying element 34 and the humidity on the anode side, that is, the front space 32 is lowered. Further, at the cathode of the dehumidifying element 34, protons (H +) and electrons generated by electrolysis react with oxygen to generate water vapor. This water vapor is discharged into the rear space 33. Thereby, the humidity inside the front space 32 can be reduced, and dew condensation inside the front space 32 can be prevented.

  In the dehumidifying element 35, as in the case of the dehumidifying element 34, in the vicinity of the anode of the dehumidifying element 35, the humidity of the anode side, that is, the front space 33 is reduced due to water electrolysis, and water vapor is generated at the cathode of the dehumidifying element 35. The water vapor is generated and discharged to the outside of the imaging device 11. Thereby, the humidity inside the rear space 33 can be reduced, and the dehumidifying effect inside the front space 32 by the dehumidifying element 34 can be further enhanced.

  That is, by dehumidifying the rear space 33 with the dehumidifying element 35, the inside of the rear space 33 can be made lower than the humidity outside the imaging device 11, and by dehumidifying the front space 32 with the dehumidifying element 34, The humidity in the space 32 can be lower than the humidity of the rear space 33. By dehumidifying the rear space 33 in this way, the humidity in the front space 32 can be further lowered, and the front space 32 can be made to be in a state in which condensation is less likely to occur. Therefore, the imaging element 23 can be cooled to a lower temperature by the cooling element 24 more easily and reliably.

  Moreover, since the rear space 33 is dehumidified and kept in a low humidity state, it is not always necessary to ensure high airtightness between the front space 32 and the rear space 33. Therefore, the chamber wall 25 that partitions the front space 32 and the rear space 33 is screwed to the external housing 21 with screws 26 and screws 27. Thus, according to the imaging device 11, since it has a high dehumidifying function, it is not always necessary to ensure high airtightness in the front space 32, and the chamber wall 25 forming the front space 32 is sealed with a gap. It can be easily attached to the external housing 21 without requiring stopping or welding. Thereby, the manufacturing cost of the imaging device 11 can be reduced.

  Moreover, according to the imaging device 11, since the dehumidification effect of the front space 32 can be improved easily, it is not necessary to use a large dehumidifying device having a higher dehumidifying effect as the dehumidifying device provided in the imaging device 11. Therefore, the size of the imaging device 11 can be reduced without being restricted by the arrangement of electronic components in the imaging device 11.

  Furthermore, since the imaging device 11 can efficiently dehumidify the front space 32, it is not necessary to provide a thermometer or a hygrometer for controlling the cooling element 24 and the dehumidifying element 34 in the front space 32. Therefore, not only the imaging device 11 can be reduced in size, but also the power consumption in the imaging device 11 can be reduced, and the cooling efficiency of the imaging device 23 and the dehumidification efficiency of the front space 32 and the rear space 33 are further improved. be able to.

  Furthermore, it is generally known that the dehumidifying efficiency increases as the space to be dehumidified becomes smaller. In the imaging device 11, since the control board 22 and the like are disposed in the front space 32, a certain volume is required. On the other hand, since the rear space 33 is relatively few, the rear space 33 has a smaller volume than the front space 32. Thus, the dehumidification efficiency of the back space 33 can be improved by making the back space 33 a space with a small volume.

  In the imaging device 11, in the figure in the front space 32, the horizontal width, that is, the inner diameter of the portion of the external housing 21 that forms the front space 32 is the horizontal width in the rear space 33, that is, the rear. Although it is smaller than the inner diameter of the portion of the outer casing 21 that forms the space 33, it is not always necessary. That is, in the figure of the rear space 33, the lateral width may be the same as the lateral width of the front space 32, or may be narrower than the lateral width of the front space 32. Alternatively, the chamber wall 30 does not necessarily have to be locked to the external housing 21. For example, a wall portion that contacts the chamber wall 30 and forms the rear space 33 may be provided on the chamber wall 25.

  In the above description, it has been described that the dehumidifying element 35 is provided on the chamber wall 30 that constitutes the casing of the imaging device 11. However, an external casing that is detachable from the casing of the imaging device 11 is provided. The dehumidifying element 35 may be provided in the external housing.

  In such a case, the imaging device 11 is configured, for example, as shown in FIG. In FIG. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The control board 22 on which the image sensor 23 and the cooling element 24 are arranged is fixed inside the external casing 71 of the imaging device 11 of FIG. A through hole is provided at a position opposite to, and the through hole is covered with the optical filter 29.

  The space inside the outer casing 71 is covered with the chamber wall 25 to be an airtight chamber. In other words, the chamber wall 25 is fixed to the outer casing 71 with screws (not shown). A groove is provided in a portion of the outer casing 71 that comes into contact with the chamber wall 25, and an O-ring 28 is fitted into the groove, so that high airtightness inside the outer casing 71 is maintained by the O-ring 28. .

  Furthermore, an external housing 72 detachably attached to the chamber wall 25 is attached to the chamber wall 25 with screws 73 and 74 so as to cover the cathode of the dehumidifying element 34. A dehumidifying element 35 is provided in a portion of the external housing 72 facing the dehumidifying element 34. That is, the dehumidifying element 35 is provided so that the dehumidifying element 34 and the dehumidifying element 35 face each other and are positioned on a substantially straight line.

  As described above, in the imaging device 11 of FIG. 2, the space formed by the outer casing 71, the optical filter 29, and the chamber wall 25 is defined as the front space 32, and the chamber wall 25 and the external casing 72 are A space formed by being surrounded is a rear space 33. The rear space 33 is a space having a smaller volume than the front space 32.

  1, the anode of the dehumidifying element 34 is exposed to the front space 32 in which the control board 22, the imaging element 23, and the cooling element 24 are arranged, and the cathode of the dehumidifying element 34 is The rear space 33 is exposed. The anode of the dehumidifying element 35 is exposed inside the external housing 72, that is, in the rear space 33, and the cathode of the dehumidifying element 35 is exposed outside the imaging device 11.

  When the subject is imaged, the dehumidifying element 34 dehumidifies the front space 32, and the dehumidifying element 35 dehumidifies the rear space 33. Thus, the dehumidifying effect in the front space 32 by the dehumidifying element 34 can be further enhanced by further dehumidifying the rear space 33 where the cathode of the dehumidifying element 34 is exposed by the dehumidifying element 35. Therefore, the humidity in the front space 32 can be further reduced, and the imaging element 23 can be cooled to a lower temperature by the cooling element 24 more easily and reliably while suppressing the occurrence of condensation.

  Further, the cathode of the dehumidifying element 34 and the anode of the dehumidifying element 35 are provided to face each other and close to each other.

  Further, in the imaging device 11, the external housing 72 can be attached to and detached from the chamber wall 25, so that the external housing 72 is attached to the chamber wall 25 according to the purpose of use of the imaging device 11. It can be incorporated into another device, or can be incorporated into another device with the external housing 72 removed from the chamber wall 25. Therefore, the imaging device 11 can be incorporated into more devices more easily, and the usage applications of the imaging device 11 can be expanded.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

It is a figure which shows the structural example of one Embodiment of the imaging device to which this invention is applied. It is a figure which shows the other structural example of an imaging device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Image pick-up device, 21 External housing | casing, 23 Image pick-up element, 24 Cooling element, 25 Room wall, 26 Screw, 27 Screw, 29 Optical filter, 30 Room wall, 32 Front space, 33 Back space, 34 Dehumidification element, 35 Dehumidification element , 71 External housing, 72 External housing

Claims (5)

A first space and a second space that are adjacent to each other and are surrounded by a housing;
An image sensor that is disposed in the first space and images a subject;
A cooling element that is disposed in the first space and that cools the imaging element;
A dehumidifying part that absorbs moisture in the first space is exposed in the first space, and a discharge part that discharges moisture dehumidified in the dehumidifying part is exposed in the second space. A first dehumidifying element for dehumidifying the first space;
A dehumidifying part that absorbs moisture in the second space is exposed to the second space, and a discharge part that releases moisture dehumidified by the dehumidifying part of the first dehumidifying element is exposed to the outside of the housing. An image pickup apparatus comprising: a second dehumidifying element arranged to be dehumidified to dehumidify the second space. The imaging device according to claim 1, wherein the second space has a smaller volume than the first space. The imaging apparatus according to claim 1, wherein the first dehumidifying element and the second dehumidifying element are arranged so as to be positioned substantially on a straight line. A partition member that forms the first space and the second space by partitioning one space surrounded by the housing;
The imaging apparatus according to claim 1, further comprising: a fixing member that fixes the partition member to the housing by screwing. The housing is
An outer housing to which the first dehumidifying element is fixed and forming the first space;
The second dehumidifying element is fixed, and includes an external housing that forms the second space and is detachable from the external housing. The imaging device according to any one of the above.

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