JP2005204062A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which can reduce the consumption of silica gel, and to shorten the waiting time for cooling for each use of imaging element. <P>SOLUTION: A CCD 21 which picks up an image and a Peltier element 23 which cools the CCD 21 are housed inside a sealed exterior cover 26b of an exterior part 26, and the silica gel 29 which dehumidifies water in a sealed space and a Peltier element 30, which forcibly cools the silica gel 29, are stored inside the exterior cover 26b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to an image pickup apparatus having a dew condensation prevention function for an image pickup element.

  It is known that a solid-state image sensor (hereinafter referred to as a CCD) used in an imaging apparatus such as a microscope deteriorates an image with an increase in ambient temperature.

  Therefore, when using such a CCD, in order to suppress the temperature rise of the CCD, for example, the whole CCD is cooled using a cooling means such as a Peltier element, and the absorbed heat is radiated to the outside air through the cover. I have to.

  However, when the CCD is cooled, moisture contained in the air in the cover may be condensed on the imaging surface of the CCD, and there is a problem that the condensed moisture is reflected in the imaging result.

  As countermeasures for this, it is conceivable that the CCD and its surroundings are completely sealed, and the product is assembled in a low-humidity environment, or the interior of the cover is filled with vacuum or nitrogen gas. However, it is very impractical to make a completely sealed structure around the CCD and its surroundings, which is very expensive. Moreover, when the sealing structure is not perfect, although it is a very small amount, moisture contained in the outside air gradually enters the inside of the cover, resulting in a problem that condensation occurs over time.

  As a countermeasure for this, conventionally known methods include, for example, as disclosed in Patent Document 1, in which silica gel is enclosed in a cover to absorb moisture inside, and as disclosed in Patent Document 2. In addition, there is a cooling control unit that cools the CCD, and the cooling control unit is cooled to a temperature lower than the CCD temperature, thereby condensing internal moisture to the cooling control unit and preventing condensation of the CCD.

  FIG. 9 is a view for explaining the feature of Patent Document 1. In FIG. In the figure, reference numeral 1 denotes a CCD for imaging, and this CCD 1 is mounted on a substrate 2. The CCD 1 is provided with a Peltier element 3. The Peltier element 3 is for cooling the CCD 1, and the cooling surface is provided on the CCD 1 via the heat conducting member 4. The heat conducting member 4 thermally connects the cooling surface of the CCD 1 and the Peltier element 3, and a material having a high heat transfer coefficient such as aluminum or copper is used. The heat conducting member 4 is provided with a thermistor 5. The thermistor 5 is for measuring the temperature of the heat conducting member 4 and notifies the temperature control unit (not shown) via the wiring (not shown) on the substrate 2.

  The Peltier element 3 is provided in close contact with the surface of the base 6 a that also serves as the heat radiating portion of the exterior portion 6. A substrate 2 to which a CCD 1 is attached is fixed to the base 6a through a stud 7. In this case, the stud 7 has the heat conducting member 4 and the Peltier element 3 sandwiched and fixed between the substrate 2 and the base 6a.

  An exterior cover 6 b is provided on the base 6 a of the exterior portion 6 so as to cover the periphery of the CCD 1. The exterior cover 6b is airtightly attached on the base 6a with screws 6c with a packing 6d interposed. The exterior cover 6b is provided with a window portion 6e into which a cover glass 8 is fitted at a position corresponding to the imaging surface of the CCD 1. The cover glass 8 is adhered to the window 6e in a sealed state using an adhesive or the like. Silica gel 9 is disposed inside the exterior cover 6b. The silica gel 9 is for dehumidifying the sealed space inside the exterior cover 6 b including the CCD 1.

  A mount 10 is provided on the exterior cover 6b. The mount 10 has a connection part for connecting the imaging device to an adapter (not shown), a mechanism for matching the center of the adapter and the center of the CCD 1, and the focal point of a lens (not shown) on the adapter side. The imaging surface of the CCD 1 is made to coincide. In this case, the mount 10 has plate-like members 10a and 10b, and the plate-like members 10a and 10b are moved in the horizontal direction in the figure by screws 10c so that the center of the adapter and the center of the CCD 1 coincide with each other. By tightening between the members 10a and 10b, the focal point of a lens (not shown) and the imaging surface of the CCD 1 are made to coincide.

  A substrate 11 having a driving circuit (not shown) for the CCD 1 and the Peltier element 3 is provided on the base 6a of the exterior portion 6 at the end opposite to the substrate 2 to which the CCD 1 is attached. The substrate 2 is electrically connected to the substrate 11 via a cable 12. Further, the substrate 11 is provided with a sealing component 13 for keeping the hole 6f of the base body 6a through which the cable 12 is inserted airtight.

  An exterior cover 14 is provided on the base 6 a so as to cover the periphery of the substrate 11. The outer cover 14 is provided with a connector 15. The connector 15 is connected to an external device (not shown) through a cable, and supplies power to each drive circuit (not shown) on the substrate 11 and transfers control signals.

  In such a configuration, the CCD 1 is cooled by the Peltier element 3 through the heat conducting member 4. The Peltier element 3 transmits heat absorbed from the CCD 1 and the heat conducting member 4 to the base body 6a of the exterior portion 6, dissipates it into the atmosphere, and transmits it to the mount 10 side via the exterior cover 6b. To dissipate heat. In this case, the thermistor 5 measures the temperature of the heat conducting member 4 and estimates the cooling temperature of the CCD 1. The estimated temperature data is transmitted from the board 2 to the board 11 through the cable 12 and is input to the personal computer of the external device through the connector 15. In the personal computer, the temperature difference from the target cooling temperature of the CCD 1 is calculated based on the temperature data, and the current flowing through the Peltier element 3 is controlled so as to reach the target temperature.

  On the other hand, the silica gel 9 absorbs moisture that enters a very small amount every day. In this case, when the amount of water changes as shown in FIG. 10 (a) due to water entering the inside of the apparatus as time passes as shown in FIG. 10, the amount of silica gel 9 is set to three levels, appropriate, small and many. In this case, changes in humidity inside the apparatus are as shown in FIGS. 5B, 5C, and 5D, respectively, and are greatly influenced by the amount of silica gel 9. As a result, when the humidity dewed on the CCD 1 is shown in FIG. 5 (e), when the amount of silica gel 9 is small, condensation occurs within a relatively short time before the product guaranteed life shown in FIG. May end up. For this reason, when assembling the imaging device, it is necessary to enclose a sufficient amount of silica gel 9 that can prevent dew condensation with respect to the total amount of moisture that enters during the product warranty lifetime.

  FIG. 11 explains the characteristics of Patent Document 2, and uses a Peltier element 16 instead of silica gel. In this case, the Peltier element 16 is disposed so that the cooling surface is in contact with the air in the sealed space covered with the exterior cover 6b and the heat dissipation surface is in contact with the base body 6a. Other parts that are the same as those in FIG. 9 are denoted by the same reference numerals.

  In such a configuration, when the CCD 1 is cooled, the Peltier element 16 is first driven and cooled. Then, moisture in the air in the sealed space starts to condense on the Peltier element 16, and as shown in FIG. 12 (a), the moisture content in the sealed space increases and the humidity inside the sealed space is as shown in FIG. descend. Then, the Peltier device 3 that cools the CCD 1 is driven with the point in time when the humidity inside the sealed space is lower than the dew condensation at the cooling temperature of the CCD 1 shown in FIG. To do.

  FIG. 13 shows a structure in which a Peltier element 16 is used in place of the silica gel described above, and a moisture discharging means 17 is further provided.

In this case, a hole 6g is provided on the side surface of the exterior cover 6b of the exterior part 6, and the discharge means 17 is provided in the hole 6g. The discharge means 17 has a sheet shape, and is arranged so that one end thereof is in contact with the cooling surface of the Peltier element 16 and the other end is in contact with the outside air through the hole 6g. In this case, the cross-sectional shapes of the hole 6g and the discharge means 17 are the same size, and it is difficult to move the air. Other parts that are the same as those in FIG. 9 are denoted by the same reference numerals. With such a configuration, moisture condensed on the Peltier element 16 is discharged to the outside through the discharge means 17.
JP-A-9-009116 JP-A-6-121207

  However, what is disclosed in FIG. 9 requires a large amount of silica gel 9 enclosed in the apparatus, resulting in an increase in the size of the apparatus. For example, when the CCD 1 is cooled to 5 ° C. in an environment of 35 ° C., it is necessary to keep the internal humidity at 15.6% or less so that the CCD 1 is not condensed. Since the moisture absorption rate (compared to the weight) of the general silica gel 9 is about 8.7%, if the silica gel 9 absorbs about 2.5% in the initial state, 15% of moisture entering the inside is assumed. A large amount of silica gel 9 more than double (weight ratio) is required.

  Further, the device disclosed in FIG. 11 has a problem that the CCD 1 cannot be immediately cooled during imaging. This is because, as described in FIG. 12, moisture in the air in the sealed space starts to condense on the Peltier element 16, and the humidity inside the sealed space increases with an increase in the amount of moisture condensed as shown in FIG. However, the temperature of the CCD 1 shown in FIG. 2C is not reduced below the humidity at which no condensation occurs at the cooling temperature of the CCD 1 as shown in FIG. It is not possible. Further, when the power of the Peltier element 16 is turned off after use, moisture condensed on the Peltier element 16 is vaporized and the humidity inside the sealed space increases again. Therefore, a cooling waiting time is required every time the CCD 1 is used. As a result, work efficiency is reduced.

  Further, what is disclosed in FIG. 13 is that the moisture discharging means 17 has a structure that allows moisture to pass through. Therefore, when the power of the Peltier element 16 is turned off after use, the moisture in the outside air flows back to the inside. The humidity inside the sealed space becomes equal to that of the outside air, and as a result, a cooling waiting time is required every time the CCD 1 is used, similar to that disclosed in FIG.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an imaging apparatus capable of reducing the amount of silica gel used and shortening the cooling waiting time when using an imaging element.

  The invention according to claim 1 is disposed inside the exterior member, an image sensor that captures an image, a cooling unit that cools the image sensor, a sealed exterior member that houses the image sensor and the cooling unit, and the like. And a silica gel for dehumidifying moisture in a sealed space of the exterior member, and a cooling means for cooling the silica gel.

  A second aspect of the invention is characterized in that, in the first aspect of the invention, a heat conducting member is interposed between the silica gel and a cooling means for cooling the silica gel.

  The invention according to claim 3 is the invention according to claim 2, wherein the heat conducting member has a vertical protruding wall on a plate-like base, and the silica gel is a vertical protruding wall of the heat conducting member. It has the recessed part in which is inserted.

  The invention according to claim 4 is the invention according to claim 2, wherein the heat conducting member has a substantially U-shaped cross section having three side surfaces, and the silica gel is inserted into a space surrounded by the three side surfaces. It is characterized by being.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the cooling means for cooling the image pickup device and the silica gel are the same cooling means.

  A sixth aspect of the invention is characterized in that, in the invention according to any one of the first to fifth aspects, the imaging element is a solid-state imaging element, and the cooling means is a Peltier element.

  A seventh aspect of the invention is characterized in that, in the sixth aspect of the invention, there is provided control means for controlling the Peltier element to a driving and non-driving state.

  The invention described in claim 8 is characterized in that, in the invention described in claim 6, there is provided control means for variably controlling the current flowing through the Peltier element.

  According to the present invention, the silica gel is forcibly cooled by the cooling means and the moisture absorption rate of the silica gel is increased, whereby the moisture in the sealed space in the exterior portion can be efficiently removed, and the amount of silica gel required. Can be greatly reduced.

  Moreover, since the humidity of the sealed space in the exterior portion can be kept low for a long period of time, the cooling waiting time when using the imaging element can be greatly shortened.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of an imaging apparatus according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 21 denotes a CCD as an image pickup device that performs image pickup. The CCD 21 is attached on a substrate 22. Further, the CCD 21 is provided with a Peltier element 23 as a cooling means. The Peltier element 23 is for cooling the CCD 21, and the CCD 21 is provided on the cooling surface via the heat conducting member 24. The heat conducting member 24 thermally connects the cooling surfaces of the CCD 21 and the Peltier element 23, and a material having a high heat transfer coefficient such as aluminum or copper is used.

  The heat conducting member 24 is provided with a thermistor 25. The thermistor 25 is for measuring the temperature of the heat conducting member 24, and notifies the measured temperature to a personal computer 37 (to be described later) via a wiring (not shown) on the substrate 22.

  The Peltier element 23 is provided in close contact with the surface of the base body 26 a that also serves as a heat dissipation portion of the exterior portion 26. A control line (not shown) for driving and controlling the Peltier element 23 is connected to a wiring (not shown) on the substrate 22.

  The substrate 22 is fixed to the base body 26 a via the studs 27. In this case, the stud 27 sandwiches and fixes the heat conducting member 24 and the Peltier element 23 between the substrate 22 and the base body 26a.

  An exterior cover 26 b is provided on the base body 26 a of the exterior portion 26 so as to cover the periphery of the CCD 21. The exterior cover 26b is airtightly attached on the base 26a with screws 26c with a packing 26d such as a rubber material interposed. The exterior cover 26 b is provided with a window portion 26 e into which a cover glass 28 is fitted at a position corresponding to the imaging surface of the CCD 21. The cover glass 28 is adhered to the window portion 26e in a sealed state using an adhesive or the like.

  Silica gel 29 is disposed inside the exterior cover 26b. The silica gel 29 is for dehumidifying the sealed space inside the exterior cover 26 b including the CCD 21.

  The Peltier element 30 is provided on the silica gel 29. The Peltier element 30 is for cooling the silica gel 29, and the silica gel 29 is provided on the cooling surface. Further, the Peltier element 30 is provided with a heat radiating surface in close contact with the surface of the base body 26 a of the exterior portion 26 so as to enhance the cooling effect of the silica gel 29. The Peltier element 30 is connected to a control line (not shown) for drive control, and this control line is connected to a wiring (not shown) on the substrate 22.

  A mount 31 is provided on the exterior cover 26b. The mount 31 has a connection part for connecting the imaging apparatus to an adapter (not shown), a mechanism for matching the center of the adapter and the center of the CCD 21, and the focal point of a lens (not shown) on the adapter side. The imaging surface of the CCD 21 is made to coincide. In this case, the mount 31 has plate-like members 31a and 31b, and the plate-like members 31a and 31b are moved in the horizontal direction in the figure by screws 31c so that the center of the adapter and the center of the CCD 21 coincide with each other. A shim having an appropriate thickness is sandwiched between 31b and 31b and tightened with a screw 31d so that the focal point of a lens (not shown) coincides with the imaging surface of the CCD 21.

  The base body 26a of the exterior portion 26 is provided with a substrate 32 having a drive circuit (not shown) for the CCD 21 and the Peltier elements 23 and 30 at the end opposite to the substrate 22 to which the CCD 21 is attached. The substrate 22 is electrically connected to the substrate 32 via a cable 33. The substrate 32 is provided with a sealing component 34 for keeping the hole 26g of the base body 26a through which the cable 33 is inserted airtight.

  The base body 26 a is provided with an exterior cover 35 so as to cover the periphery of the substrate 32. The exterior cover 35 is provided with a connector 36. A personal computer 37 as control means is connected to the connector 36 via a cable 38. The personal computer 37 controls the current value passed through the Peltier element 23 based on the temperature data sent from the thermistor 25, and controls the driving state and non-driving state of the Peltier element 30 that cools the silica gel 29. This makes it possible to control the value of the current that flows.

  In such a configuration, the CCD 21 is cooled by the Peltier element 23 through the heat conducting member 24. The Peltier element 23 transfers heat absorbed from the CCD 21 and the heat conducting member 24 to the exterior cover 35 via the base body 26a of the exterior portion 26, dissipates it into the atmosphere, and also displaces it to the mount 31 via the exterior cover 26b. Transmits heat to the atmosphere.

  In this state, the thermistor 25 measures the temperature of the heat conducting member 24 and estimates the cooling temperature of the CCD 21. The estimated temperature data is transmitted from the board 22 to the board 32 via the cable 33 and is input to the personal computer 37 from the connector 36. The personal computer 37 calculates a temperature difference from the target cooling temperature of the CCD 21 based on the temperature data at this time, and controls the value of the current flowing through the Peltier element 23 so as to reach the target temperature.

  The silica gel 29 absorbs moisture that enters a very small amount every day. The silica gel 29 is forcibly cooled by the Peltier element 30. The Peltier element 30 radiates the heat absorbed from the silica gel 29 to the atmosphere via the base body 26 a of the exterior portion 26.

  When the silica gel 29 is forcibly cooled in this way, the ambient temperature of the silica gel 29 decreases and the humidity increases. FIG. 2 shows the relationship between the humidity and the moisture absorption rate of the silica gel 29. The silica gel 29 has a higher moisture absorption rate as the ambient humidity increases. It is also known that the moisture absorption rate of the silica gel 29 has almost no temperature dependence.

  As a result, when the silica gel 29 is forcibly cooled by the Peltier element 30, the moisture absorption rate of the silica gel 29 increases due to an increase in ambient humidity, so that moisture in the sealed space in the exterior cover 26b can be efficiently removed. The amount of silica gel 29 required can be greatly reduced. In addition, since the amount of the silica gel 29 can be reduced, the overall size of the exterior portion 26 having the exterior cover 26b can be reduced. Therefore, design restrictions can be reduced, and system performance when attached to a microscope or the like is improved. In addition, since the space volume inside the exterior cover 26b can be reduced, the amount of heat absorbed by the Peltier element 30 to the interior of the exterior cover 26b can be reduced, and the cooling efficiency can be improved.

  On the other hand, as shown in FIG. 3, with the passage of time, if the amount of water changes as shown in FIG. (B), the change in humidity when the silica gel 29 is cooled is as shown in FIG. 5 (c), and is greatly influenced by the conditions with and without the silica gel 29 being cooled. . As a result, assuming that the humidity dew condensation on the CCD 21 is (d) in the figure, if the silica gel 29 is not cooled, there is a risk that dew condensation will occur within a relatively short time that does not reach the product life shown in FIG. However, when the silica gel 29 is cooled, the internal humidity can be kept low for a long time even after the product life shown in FIG. The waiting time can be greatly reduced.

Incidentally, for example, when the CCD 21 is cooled to 5 ° C. in an environment of 35 ° C., it is necessary to keep the internal humidity at 15.6% or less so that the CCD 21 does not condense. Since the moisture absorption rate (weight comparison) of general silica gel 29 is about 8.7%, if the silica gel 29 is cooled to 5 ° C., the relative humidity around the silica gel 29 may be 90% or less. In other words, the moisture absorption rate of the general silica gel 29 at that time is about 40%. Thus, when 2.5% of the initial moisture absorption rate of the silica gel 29 is taken into consideration, the amount of the silica gel 29 is about 1/6 that when the silica gel 29 is not actually cooled.

  Furthermore, even if the power source of the Peltier device 30 is turned off after the use is completed, if the silica gel 29 that does not release moisture once absorbed is used, the internal humidity does not increase rapidly. Further, since there is no moisture discharging means as described above, and moisture does not flow back from the outside, the internal humidity does not rise rapidly. As a result, condensation does not occur unless a very small amount of water that enters through the sealed structure and intrudes during storage from the use of the imaging device to the next use exceeds the humidity at which the CCD 21 is condensed.

  Next, as shown in FIG. 4, assuming that the amount of moisture changes as shown in FIG. 4A due to moisture that gradually enters the inside of the device as time passes, the imaging device is used continuously ( Change in humidity (about once a week) is shown in (b) of the figure, and in the case of spot use with a short cycle (about every two to three months), in (c) of the figure. When used in a spot manner in a long cycle (about every second year), it is as shown in FIG. That is, FIG. 4 shows the state of humidity change inside the apparatus when the imaging apparatus is spot-used in a short cycle and a long cycle, and the short cycle and the long cycle are periods in which the humidity is rising. Is a period in which the humidity is abruptly decreasing, a period in which the humidity is rapidly decreasing, and a period in which the humidity is rapidly decreasing is a phenomenon that occurs because the moisture absorption rate increases due to forced cooling of the silica gel 29. is there.

  As is apparent from FIG. 4, when the apparatus is used continuously (FIG. 4B), the CCD 21 shown in FIG. Even when it is used in a spot-like manner in a short cycle (Fig. (C)), within the period up to the product warranty life shown in Fig. (E), (f) ), The humidity that condenses on the CCD 21 is not exceeded, and there is no problem. However, when it is used in a spot-like manner in a long cycle ((d) in the figure), humidity exceeding the condensation on the CCD 21 shown in (f) in the figure is exceeded by the period until the product warranty life shown in (e) in the figure. There is.

  Therefore, for safety reasons, when the storage period exceeding two to three months is used, an instruction is issued from the personal computer 37 until the internal humidity temporarily drops below the humidity at which condensation occurs on the CCD 21. Drive. In this case, for example, a forced cooling button for the silica gel 29 is attached to the screen (not shown) of the personal computer 37, and the Peltier element 30 for cooling the silica gel 29 is turned on by manually turning on the button. What is necessary is just to make it become a drive state. Alternatively, the start button and the ON time may be input on the personal computer 37 side, and when the start button is pressed, the Peltier element 30 is set in the driving state, and the non-driving state is automatically set after the ON time has elapsed. In addition, when used for a spot in a continuous or short cycle after long-term storage, the above-described operation may be performed only for the first time after long-term storage.

  In this way, the frequency of work can be greatly reduced as compared with the conventional work required for each of the storage periods as in the prior art.

  Further, after moisture inside is absorbed by the silica gel 29 and becomes sufficiently low, wasteful heat radiation to the exterior portion 26 can be suppressed by bringing the Peltier element 30 into a non-driven state. A temperature rise can be prevented and power consumption can be reduced.

  As shown in FIG. 5, when the amount of moisture changes as shown in FIG. 5A due to moisture that gradually enters the apparatus over time, the Peltier element 30 that cools the silica gel 29 is always driven. The change in internal humidity as shown in FIGS. 2B and 2C can be obtained in the case of normal operation and in the case of driving for a certain period of time, respectively. However, the moisture absorption rate of the silica gel 29 is compared with the moisture penetration rate. Since each stage is fast, even if it is not always driven, even if it is repeatedly driven for a certain period of time after moisture has accumulated to some extent, the same effect as that of always driving can be obtained. In such an operation, the Peltier element 30 that cools the silica gel 29 is driven according to an instruction from the personal computer 37. After a certain time (t1) has elapsed, the Peltier element 30 is deactivated, and the certain time (t2) has elapsed. Then, the driving state may be set again.

  Further, in the above description, the Peltier element 30 is controlled to be driven or not driven according to an instruction from the personal computer 37. However, the personal current flowing through the Peltier element 30 may be made variable by the personal computer 37. As a control method in this case, a known control method similar to the control for the Peltier element 23 for cooling the CCD 21 is used. In this way, by flowing a large current to the Peltier element 30 at the start of the cooling of the silica gel 29, it is possible to quickly cool to the cooling target temperature. Reduction of electric power and unnecessary temperature rise of the exterior part 26 can also be prevented.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.

  FIG. 6 shows a schematic configuration of the imaging apparatus according to the second embodiment, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

  In this case, the heat conducting member 41 is disposed between the silica gel 29 and the Peltier element 30. The heat conducting member 41 has a vertical protruding wall 41 b on a plate-like base 41 a, and the back surface of the base 41 a is attached to the cooling surface of the Peltier element 30. Further, the silica gel 29 has a recess 29a, and the protruding wall 41b of the heat conducting member 41 is inserted into the recess 29a. Thereby, the silica gel 29 contacts the base 41a and the protruding wall 41b of the heat conducting member 41, and the contact area with the heat conducting member 41 is increased. The heat conducting member 41 is preferably made of a material having a high heat transfer coefficient such as aluminum or copper.

  In this way, since the silica gel 29 has a large contact area with the heat conducting member 41, the thermal resistance during this time can be greatly reduced, so that the heat conduction during cooling by the Peltier element 30 becomes good, Powerful cooling and low ambient temperature. Thereby, the relative humidity around the silica gel 29 becomes higher and the moisture absorption rate is improved, so that condensation of the CCD 21 can be prevented more stably.

(Third embodiment)
Next, a third embodiment of the present invention will be described.

  FIG. 7 shows a schematic configuration of an imaging apparatus according to the third embodiment, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

  Also in this case, another heat conducting member 42 is disposed between the silica gel 29 and the Peltier element 30. The heat conduction member 42 has three side surfaces and a substantially U-shaped cross section, and one side surface is attached to the cooling surface of the Peltier element 30. Silica gel 29 is inserted into the hollow portion surrounded by the three side surfaces of the heat conducting member 42. As a result, the silica gel 29 is in contact with the three sides of the heat conducting member 42 at the periphery, and the contact area with the heat conducting member 42 is increased. Also in this case, the heat conducting member 42 is preferably made of a material having a high heat transfer coefficient such as aluminum or copper.

  Even in this case, since the silica gel 29 has a large contact area with the heat conducting member 42, the thermal resistance during this time can be greatly reduced, so that the heat conduction at the time of cooling by the Peltier element 30 becomes good, Powerful cooling and low ambient temperature. Thereby, the relative humidity around the silica gel 29 can be made higher, and the moisture absorption rate of the silica gel 29 can be improved, so that condensation of the CCD 21 can be prevented more stably.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.

  FIG. 8 shows a schematic configuration of an imaging apparatus according to the fourth embodiment, and the same parts as those in FIG. 1 are denoted by the same reference numerals.

  In this case, a heat conducting member 43 is arranged between the CCD 21 and the Peltier element 23 instead of the above-described heat conducting member 24. The heat conducting member 43 has one end portion that extends greatly, and a silica gel holding portion 43a having a substantially U-shaped cross section having three side surfaces is formed in the extending portion. The silica gel 29 is inserted and held in the silica gel holding portion 43a. Also in this case, the heat conducting member 43 is preferably made of a material having a high heat transfer coefficient such as aluminum or copper.

  In this way, by driving the Peltier element 23, both the CCD 21 and the silica gel 29 can be cooled at the same time. Therefore, the Peltier element for cooling the silica gel 29 exclusively can be omitted. The number of parts can be reduced, and the power consumption for driving the Peltier element can also be reduced.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary. For example, in the above-described embodiment, the Peltier element is described as the cooling means, but a heat pump may be used instead.

  Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

The figure which shows schematic structure of the 1st Embodiment of this invention. The figure which shows the relationship between the relative humidity and the moisture absorption rate of the silica gel for demonstrating 1st Embodiment. The figure which shows the relationship between elapsed years and humidity for demonstrating 1st Embodiment. The figure which shows the relationship between elapsed years and humidity for demonstrating 1st Embodiment. The figure which shows the relationship between elapsed years and humidity for demonstrating 1st Embodiment. The figure which shows schematic structure of the 2nd Embodiment of this invention. The figure which shows schematic structure of the 3rd Embodiment of this invention. The figure which shows schematic structure of the 4th Embodiment of this invention. 1 is a diagram illustrating a schematic configuration of an example of a conventional imaging device. The figure which shows the relationship between elapsed years and humidity for demonstrating the conventional imaging device. FIG. 10 is a diagram illustrating a schematic configuration of another example of a conventional imaging device. The figure which shows the relationship between the elapsed time from power activation, and humidity for demonstrating the conventional imaging device. FIG. 10 is a diagram illustrating a schematic configuration of another example of a conventional imaging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 ... CCD, 22 ... Board | substrate, 23 ... Peltier device 24 ... Thermal conduction member, 25 ... Thermistor 26 ... Exterior part, 26a ... Base | substrate, 26b ... Exterior cover 26d ... Packing, 26c ... Screw, 26e ... Window part 26g ... Hole 27 ... Stud, 28 ... Cover glass 29 ... Silica gel, 29a ... Recess 30 ... Peltier element, 31 ... Mount 31a, 31b ... Plate member, 31c, 31d ... Screw 32 ... Substrate, 33 ... Cable 34 ... Sealing part, 35 ... Exterior cover 36 ... Connector 37 ... PC 38 ... Cable 41 ... Heat conduction member 41a ... Base 41b ... Projection wall 42 ... Heat conduction member 43 ... Heat conduction member 43a ... Silica gel holding part

Claims (8)

An image sensor for capturing an image;
Cooling means for cooling the image sensor;
A sealed exterior member that houses the imaging device and the cooling means;
Silica gel that is disposed inside the exterior member and dehumidifies the moisture in the sealed space of the exterior member;
An imaging apparatus comprising: a cooling means for cooling the silica gel. 2. The imaging apparatus according to claim 1, wherein a heat conducting member is interposed between the silica gel and a cooling means for cooling the silica gel. The said heat conductive member has a perpendicular | vertical protruding wall on a plate-shaped base, The said silica gel has a recessed part in which the perpendicular | vertical protruding wall of the said heat conductive member is inserted. Imaging device. The imaging apparatus according to claim 2, wherein the heat conducting member has a substantially U-shaped cross section having three side surfaces, and the silica gel is inserted into a space surrounded by the three side surfaces. The imaging apparatus according to claim 1, wherein the cooling means for cooling each of the imaging element and the silica gel includes the same cooling means. 6. The imaging apparatus according to claim 1, wherein the imaging element is a solid-state imaging element, and the cooling unit is a Peltier element. The imaging apparatus according to claim 6, further comprising a control unit that controls the Peltier element to be in a driving and non-driving state. The imaging apparatus according to claim 6, further comprising a control unit that variably controls a current flowing through the Peltier element.

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