Heat producing device and imaging device

Abstract

A heat producing device (4) according to the present disclosure comprises: a substrate (5); an inner electrode (6, 31) that is formed on the substrate (5) in a linear shape so as to surround a prescribed region; an outer electrode (7) that is formed on the substrate (5) in a linear shape so as to surround the inner electrode (6, 31); and a resistor (8) that is positioned so as to electrically connect the inner electrode (6, 31) and the outer electrode (7) and produces heat when current is passed therethrough.

Description

Heat generating device and imaging device

[0001] The present disclosure relates to a heat generating device and an imaging device.

[0002] Heat generating devices that heat a heating target have been put to practical use for some time. For example, a heating device can be arranged to heat the windshield when capturing an image of the outside of a vehicle using an imaging device from inside the vehicle. This can prevent fogging of the windshield and reduce degradation of image quality of the imaging unit. Here, the heating device is required to heat the heating target uniformly.

[0003] Therefore, as a technology for uniformly heating an object to be heated, for example, Patent Document 1 proposes a sheet heating element that maintains uniform thermal conduction even after printing an insulating substrate. This sheet heating element prevents thermal deformation by gradually tempering aluminum foil deposited on the insulating substrate, thereby achieving uniform thermal conductivity.

[0004] JP 2011-228308 A

[0005] However, the sheet heating element of Patent Document 1 is difficult to miniaturize because the carbon paste is formed in a serpentine pattern at regular intervals. For example, there are cases where the heating device needs to be placed in a narrow area, avoiding the functional area of ​​the heating target. For example, when placing a heating device on the lens of an imaging device, it is necessary to place the heating device in a place that avoids the central part of the lens through which light passes. In this case, it is difficult to place the sheet heating element of Patent Document 1 in a narrow outer area that avoids the central part of the lens.

[0006] The present disclosure aims to provide a heat generating device and an imaging device that can be placed in a small area.

[0007] The heat generating device according to the present disclosure comprises a substrate, an inner electrode formed linearly on the substrate so as to surround a predetermined region, an outer electrode formed linearly on the substrate so as to surround the inner electrode, and a resistor arranged to electrically connect the inner electrode and the outer electrode, which generates heat when electricity is passed through it.

[0008] The imaging device according to the present disclosure has the above-described heat generating device disposed relative to the lens.

[0009] According to the present disclosure, it is possible to arrange it in a narrow range.

[0010] FIG. 1 is a diagram showing the configuration of an imaging device including a heat generating device according to a first embodiment of the present disclosure. FIG. 2 is a diagram showing the configuration of a heat generating device in the first embodiment. FIG. 3 is a diagram showing the configuration of an inner electrode in the first embodiment. FIG. 4 is a diagram showing the configuration of a heat generating device in the second embodiment. FIG. 5 is a diagram showing the configuration of a heat generating device in the third embodiment. FIG. 6 is a diagram showing the configuration of a heat generating device in the fourth embodiment. FIG. 7 is a diagram showing the configuration of a heat generating device in a modified example of the fourth embodiment. FIG. 8 is a diagram showing the configuration of a heat generating device in the fifth embodiment.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0012] 1 shows the configuration of an imaging device 1 equipped with a heat generating device according to a first embodiment of the present disclosure. The imaging device 1 includes a device body 2, a lens 3, and a heat generating device 4. The imaging device 1 can be mounted in, for example, a vehicle. For example, the imaging device 1 may be installed inside the vehicle so as to capture an image of the outside of the vehicle through the vehicle window.

[0013] The device body 2 incorporates an optical unit including a lens 3, an imaging element, etc. For example, the device body 2 captures an image of a subject formed on the imaging element by the lens 3, and outputs an image signal of the image.

[0014] The lens 3 is disposed within a lens barrel of the device body 2, and forms an incident optical image on the imaging element. For example, a plurality of lenses may be disposed so as to be aligned in the optical axis direction.

[0015] The heating device 4 is disposed near the lens 3 to heat the lens 3. The heating device 4 is disposed, for example, on the rear surface side of the lens 3. When a plurality of lenses 3 are disposed, the heating device 4 may be disposed for at least one of the lenses 3. For example, the heating device 4 may be disposed for the frontmost lens 3 or the rearmost lens 3.

[0016] Next, the configuration of the heating device 4 will be described in detail.

[0017] 2, the heating device 4 includes a substrate 5, an inner electrode 6, an outer electrode 7, and a resistor 8. For example, the heating device 4 is connected to a control unit 10 via a power source 9.

[0018] The substrate 5 has a flat plate shape and is made of an insulating material. A predetermined region R is defined in the center of the substrate 5, and an opening 5a is formed in the region R. The region R is defined according to the functional range through which light passes in the lens 3 (e.g., a range corresponding to the aperture), i.e., the region R is defined so that light focused by the lens 3 passes through the opening 5a. This allows the substrate 5 to be positioned so as to avoid the travel range of light that passes through the lens 3. In this case, the substrate 5 may be directly attached to the lens 3. The substrate 5 may also be disposed on a support that supports the lens 3. In other words, the substrate 5 may be disposed on a component of the imaging device 1 that can conduct heat to the lens 3. The substrate 5 may also be formed, for example, from a sheet-like flexible substrate. The substrate 5 may also be formed, for example, from polyethylene terephthalate, polyimide, liquid crystal polymer, or the like.

[0019] Although the opening 5a is formed in the substrate 5, it is not limited to this as long as it does not impede the function of the object to be heated. For example, a light-transmitting film may be disposed on the substrate 5 in correspondence with the predetermined region R. Furthermore, the predetermined region R is set according to the functional range of the lens 3, but it is not limited to this as long as it can be set according to the function or use of the object to be heated.

[0020] The inner electrode 6 is made of a conductive material and electrically connects the power source 9 and the resistor 8. The inner electrode 6 is formed linearly on the substrate 5 so as to surround the region R. For example, the inner electrode 6 has a base end 6a, a tip end 6b, and a linear portion 6c. The base end 6a forms a terminal to which the power source 9 is connected. The tip end 6b is disposed near the region R. The linear portion 6c is disposed so as to extend from the base end 6a toward the tip end 6b. In this case, the linear portion 6c is drawn from the base end 6a toward the region R, and then formed so as to circle the region R along the region R in the vicinity thereof and connect to the tip end 6b. Here, the linear portion 6c does not completely surround the region R, but is formed so as to leave a gap S1 between the tip end 6b surrounding the region R and the base end side.

[0021] The outer electrode 7 is made of a conductive material and electrically connects the power source 9 and the resistor 8. The outer electrode 7 is formed linearly on the substrate 5 to surround the inner electrode 6. For example, the outer electrode 7 has a base end 7a, a tip end 7b, and a linear portion 7c. The base end 7a forms a terminal to which the power source 9 is connected. The tip end 7b is located near the inner electrode 6. The linear portion 7c is arranged to extend from the base end 7a toward the tip end 7b. In this case, the linear portion 7c is extended from the base end 7a toward the inner electrode 6, and then formed to wrap around the inner electrode 6 and connect to the tip end 7b. Here, the linear portion 7c does not completely surround the inner electrode 6. Rather, the tip end 7b surrounding the inner electrode 6 and the base end side are formed to sandwich the extended portion of the linear portion 6c extended from the base end 6a toward the region R of the inner electrode 6, with gaps S2 and S3 between them.

[0022] The resistor 8 is disposed so as to electrically connect the inner electrode 6 and the outer electrode 7, and has a resistance value that generates heat when current is applied. For example, the resistor 8 can be disposed so as to cover the inner electrode 6 and the outer electrode 7. That is, the resistor 8 is disposed so as to fill the space between the inner electrode 6 and the outer electrode 7. In this case, the resistor 8 is disposed so as to cover, for example, the portions of the inner electrode 6 and the outer electrode 7 that face each other, i.e., the portions excluding the intervals S1 to S3. Here, the resistor 8 may be formed, for example, of a material whose resistance value changes in response to the heat generation temperature. For example, the resistor 8 may be formed of a material having a PTC (Positive Temperature Coefficient) characteristic, i.e., a positive temperature coefficient.

[0023] The power supply 9 supplies power to the inner electrode 6 and the outer electrode 7 so that the resistor 8 generates heat, and is connected to the base end 6a and the base end 7a.

[0024] The control unit 10 controls the heat generation of the resistor 8 by switching the power supply 9 on and off. For example, the control unit 10 may turn on the power supply 9 when the imaging device 1 is turned on. Alternatively, the control unit 10 may switch the power supply 9 on and off based on the temperature or humidity of the environment in which the lens 3 is placed. For example, the control unit 10 may set a heating start temperature in advance based on the temperature at which fogging occurs on the lens 3, and switch the power supply 9 on and off based on whether the inside or outside of the imaging device 1 has reached the heating start temperature. Alternatively, the control unit 10 may set a heating start humidity in advance based on the humidity at which fogging occurs on the lens 3, and switch the power supply 9 on and off based on whether the inside or outside of the imaging device 1 has reached the heating start humidity.

[0025] Next, the configuration of the inner electrode 6 will be described in detail.

[0026] As shown in FIG. 3 , the inner electrode 6 includes an electrode body 11 and a plated portion 12. The electrode body 11 is linearly formed on the substrate 5. The electrode body 11 may be made of a material such as copper or stainless steel. The plated portion 12 is composed of three layers: a lower layer 12a, an intermediate layer 12b, and an upper layer 12c. The lower layer 12a is made of a nickel-containing material (e.g., composed predominantly of nickel) and is formed on the electrode body 11. The upper layer 12c is made of a gold-containing material (e.g., composed predominantly of gold). The intermediate layer 12b is made of a palladium-containing material (e.g., composed predominantly of palladium) and is disposed between the lower layer 12a and the upper layer 12c. A resistor 8 (not shown) is disposed above the upper layer 12c. The outer electrode 7 has the same configuration as the inner electrode 6, and therefore will not be described here.

[0027] Next, the operation of the first embodiment will be described.

[0028] First, as shown in Fig. 1, the imaging device 1 captures an image of a subject. At this time, as shown in Fig. 2, the heating device 4 disposed relative to the lens 3 heats the lens 3. For example, the control unit 10 may turn on the power supply 9 when the imaging device 1 is turned on. Alternatively, the control unit 10 may turn on the power supply 9 based on the temperature or humidity of the environment in which the lens 3 is placed. When the power supply 9 is turned on, it supplies power to the base end 6a of the inner electrode 6 and the base end 7a of the outer electrode 7.

[0029] As a result, current is passed through the resistor 8 via the inner electrode 6 and the outer electrode 7, causing the resistor 8 to generate heat. At this time, the inner electrode 6 is formed linearly so as to surround the region R, and the outer electrode 7 is formed linearly so as to surround the inner electrode 6. The resistor 8 then electrically connects the inner electrode 6 and the outer electrode 7, generating heat so as to surround the region R. Therefore, the resistor 8 can easily heat the lens 3, which is the heating target, from the side.

[0030] In this case, the inner electrode 6 and the outer electrode 7 are formed linearly along the region R, surrounding the region R, without meandering. This allows the distance between the inner electrode 6 and the outer electrode 7, i.e., the width of the resistor 8, to be narrow. Furthermore, since the region R is set according to the functional range of the lens 3 through which light passes, the heating device 4 can be disposed in a narrow range outside the functional range of the lens 3.

[0031] The resistor 8 is disposed so as to cover the area between the inner electrode 6 and the outer electrode 7. Therefore, the resistor 8 can increase the amount of heat applied to the lens 3.

[0032] Furthermore, the resistor 8 is made of a material having a positive temperature coefficient, which prevents the heating temperature of the lens 3 from rising too much and keeps the heating temperature within a predetermined range.

[0033] In this way, when the lens 3 is heated from the side, the heat is conducted toward the center of the lens 3. This makes it possible to suppress fogging of the lens 3 without impairing the function of the lens 3. As a result, the imaging device 1 can suppress degradation in image quality and capture a clear image of the subject.

[0034] Here, there is a risk that the inner electrode 6 and the outer electrode 7 may be oxidized due to moisture in the imaging device 1. For example, as shown in Fig. 3, the lower layer 12a of the plated portion 12 contains nickel, and there is a risk that oxidation may progress in this lower layer 12a. In particular, the resistor 8 made of a material having PTC characteristics tends to absorb moisture, and this moisture may significantly accelerate the oxidation of the inner electrode 6 and the outer electrode 7.

[0035] Therefore, in the present disclosure, an intermediate layer 12b containing palladium is disposed between the lower layer 12a and the upper layer 12c in the plated portion 12 of the inner electrode 6 and the outer electrode 7. This allows the intermediate layer 12b to suppress the penetration of moisture into the lower layer 12a and the like, thereby suppressing oxidation of the inner electrode 6 and the outer electrode 7.

[0036] Then, for example, when the power supply of the imaging device 1 is turned off, the control unit 10 may turn off the power supply 9. This stops the power supply to the resistor 8, and the resistor 8 stops generating heat.

[0037] According to this embodiment, the inner electrode 6 is formed linearly on the substrate 5 so as to surround a predetermined region R, and the outer electrode 7 is formed linearly on the substrate 5 so as to surround the inner electrode 6. The resistor 8 is then disposed so as to electrically connect the inner electrode 6 and the outer electrode 7. This allows the gap between the inner electrode 6 and the outer electrode 7, i.e., the width of the resistor 8, to be narrow, and the heating device 4 can be disposed in a narrow range that avoids the region R.

[0038] Second Embodiment Hereinafter, a second embodiment of the present disclosure will be described. Here, differences from the first embodiment will be mainly described, and common reference numerals will be used to designate common features with the first embodiment, and detailed descriptions thereof will be omitted.

[0039] In the above-mentioned embodiment 1, the resistor 8 is arranged so as to cover the inner electrode 6 and the outer electrode 7 except for the gaps S1 to S3, but this is not limited to this as long as it can electrically connect the inner electrode 6 and the outer electrode 7.

[0040] 4, the resistor 8 may be disposed so as to surround the entire periphery of the region R. This allows the resistor 8 to generate heat so as to surround the entire periphery of the functional range of the lens 3, thereby reliably suppressing fogging of the lens 3.

[0041] Furthermore, the outer electrode 7 may be arranged, for example, such that the distal end 7b and the proximal end side of the linear portion 7c surrounding the inner electrode 6 are sandwiched between the lead-out portion of the linear portion 6c of the inner electrode 6 that is led from the proximal end 6a toward the region R, with the same intervals S2 and S3 between them. This allows the resistor 8 to heat the lens 3 at a uniform temperature in the portions corresponding to the intervals S2 and S3, without causing a local rise in heat generation temperature. The inner electrode 6 may be arranged such that the distal end 6b and the proximal end side of the linear portion 6c surrounding the region R are separated by the same interval S1 as the intervals S2 and S3. This allows the resistor 8 to heat the lens 3 at a uniform temperature in the portions corresponding to the intervals S1 to S3.

[0042] Furthermore, the inner electrode 6 and the outer electrode 7 may be formed so that the intervals S1 to S3 are greater than or equal to the interval between the inner electrode 6 and the outer electrode 7 (the width of the resistor 8) in the direction intersecting the region R. This makes it possible to prevent the temperature of the resistor 8 from rising more in the portions corresponding to the intervals S1 to S3 than in other portions.

[0043] According to this embodiment, the resistor 8 is disposed so as to surround the entire circumference of the predetermined region R. Therefore, the resistor 8 can heat the entire functional range of the lens 3, and fogging of the lens 3 can be reliably suppressed.

[0044] Third Embodiment Hereinafter, a third embodiment of the present disclosure will be described. Here, the differences from the first and second embodiments will be mainly described, and common reference numerals will be used for common features with the first and second embodiments, and detailed description thereof will be omitted.

[0045] In the above-mentioned embodiments 1 and 2, the inner electrode 6 is arranged so that there is a gap S1 between the tip end 6b and the base end side of the linear portion 6c surrounding the region R, but it may also be arranged so as to surround the entire circumference of the region R.

[0046] For example, as shown in Fig. 5, an inner electrode 31 may be disposed instead of the inner electrode 6 of the second embodiment. The inner electrode 31 has a base end 31a and a linear portion 31b. The base end 31a forms a terminal to which the power supply 9 is connected. The linear portion 31b is drawn from the base end 31a toward the region R and is formed so as to surround the entire periphery of the region R. In other words, the linear portion 31b completely surrounds the region R. This increases the area of ​​the resistor 8 that connects the inner electrode 31 and the outer electrode 7, thereby increasing the amount of heat that the lens 3 can receive.

[0047] Furthermore, the outer electrode 7 may be arranged, for example, such that the distal end 7b and the proximal end side of the linear portion 7c surrounding the inner electrode 31 are sandwiched, with the same intervals S2 and S3 between them, with respect to the lead-out portion of the linear portion 31b of the inner electrode 31 that is led out from the proximal end 31a toward the region R. This allows the resistor 8 to heat the lens 3 at a uniform temperature in the portions corresponding to the intervals S2 and S3, without causing a local rise in heat generation temperature.

[0048] According to this embodiment, the inner electrode 31 is disposed so as to surround the entire circumference of the predetermined region R. This allows the resistor 8 to increase the amount of heat applied to the lens 3, thereby effectively suppressing fogging of the lens 3.

[0049] Fourth Embodiment Hereinafter, a fourth embodiment of the present disclosure will be described. Here, the differences from the first to third embodiments will be mainly described, and common reference numerals will be used for common features with the first to third embodiments, and detailed description thereof will be omitted.

[0050] In the first to third embodiments described above, the outer electrode 7 is formed so as to surround the inner electrode in a rectangular shape, but the invention is not limited to this as long as it is formed so as to surround the inner electrode.

[0051] For example, the outer electrode 7 may be formed to surround the inner electrode while maintaining a predetermined distance therebetween. For example, as shown in FIG. 6 , the outer electrode 7 and the inner electrode 6 may be formed so that their corners are curved. In this case, the outer electrode 7 and the inner electrode 6 are formed so that the distance S4 between their straight portions is the same as the distance S5 between their curved portions. That is, the outer electrode 7 and the inner electrode 6 are formed to surround the region R while maintaining the same distance. As a result, the resistor 8 is formed to surround the region R while maintaining the same width. The resistor 8 generates a constant amount of heat in the circumferential direction of the region R, allowing the lens 3 to be heated uniformly.

[0052] In this embodiment, the outer electrode 7 is formed into a shape having straight and curved portions. However, the shape is not limited thereto as long as the outer electrode 7 is formed to surround the inner electrode 6 while maintaining a predetermined distance. For example, as shown in FIG. 7 , the outer electrode 7 and the inner electrode 6 can be formed into a circular shape. Here, a circular region R is defined on the substrate 5, and an opening 5a is formed in the region R. The linear portion 6c of the inner electrode 6 is drawn from the base end 6a toward the region R, then formed circularly along the region R to surround the region R and connected to the tip end 6b. The linear portion 7c of the outer electrode 7 is drawn from the base end 7a toward the inner electrode 6, then formed circularly along the inner electrode 6 to surround the inner electrode 6 and connected to the tip end 7b. That is, the outer electrode 7 and the inner electrode 6 are formed to surround the region R while maintaining the same distance S6. As a result, the resistor 8 is formed to surround the region R while maintaining the same width. The resistor 8 generates a constant amount of heat in the circumferential direction of the region R, thereby uniformly heating the lens 3.

[0053] According to this embodiment, the outer electrode 7 is formed to surround the inner electrode 6 while maintaining a predetermined distance therebetween. This allows the resistor 8 to generate a constant amount of heat in the circumferential direction of the region R, thereby enabling the lens 3 to be heated uniformly.

[0054] Fifth Embodiment Hereinafter, a fifth embodiment of the present disclosure will be described. Here, the differences from the first to fourth embodiments will be mainly described, and common reference numerals will be used for common features with the first to fourth embodiments, and detailed description thereof will be omitted.

[0055] In the fifth embodiment, the resistor 8 may have a slit formed therein.

[0056] For example, as shown in Fig. 8, the resistor 8 may be disposed so as to cover the space between the inner electrode 6 and the outer electrode 7, and may have a plurality of slits 51 formed therein. The plurality of slits 51 may be formed, for example, in a direction intersecting the inner electrode 6 or the outer electrode 7. For example, the plurality of slits 51 may be formed so as to extend from the inner electrode 6 to the outer electrode 7. In this case, the plurality of slits 51 may or may not reach the bottom surface of the resistor 8 in the thickness direction of the resistor 8. In other words, it is sufficient that the plurality of slits 51 are formed partway through the resistor 8 in the thickness direction. This allows the resistor 8 to follow the deformation when the substrate 5 or the like is deformed, thereby suppressing deterioration of the resistor 8.

[0057] According to this embodiment, the resistor 8 is disposed so as to cover the space between the inner electrode 6 and the outer electrode 7, and has a plurality of slits 51. This makes it possible to suppress deterioration of the resistor 8.

[0058] In the above-described first to fifth embodiments, the heating device 4 is disposed relative to the lens 3, but the present invention is not limited to this and may be disposed relative to the object to be heated.

[0059] Furthermore, in the above-described first to fifth embodiments, the power supply 9 is connected to the control unit 10, but this is not limiting as long as it can supply power to the inner electrode 6 and the outer electrode 7. For example, in the first embodiment, the heating device 4 may be configured without the control unit 10. The resistor 8 is heated by the power supply 9. At this time, the resistor 8 is made of a material having a positive temperature coefficient, so that the heating temperature can be maintained within a predetermined range.

[0060] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be interpreted as being limited by these embodiments. In other words, the present invention can be embodied in various forms without departing from the gist or main features thereof. For example, the disclosure of the shapes and numbers of each part described in the above-described embodiments is merely illustrative and can be modified as appropriate.

[0061] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2023-110779, filed on July 5, 2023, are incorporated herein by reference in their entirety.

[0062] The heat generating device according to the present disclosure can be used in devices that generate heat when electricity is applied.

[0063] 1 Imaging device 2 Device body 3 Lens 4 Heat generating device 5 Substrate 5a Opening 6, 31 Inner electrode 6a, 31a Base end 6b Tip 6c, 31b Linear portion 7 Outer electrode 7a Base end 7b Tip 7c Linear portion 8 Resistor 9 Power source 10 Control unit 11 Electrode body 12 Plated part 12a Lower layer 12b Intermediate layer 12c Upper layer 51 Slit S1 to S6 Interval

Claims

1. A heating device comprising: a substrate; an inner electrode formed linearly on the substrate so as to surround a specified region; an outer electrode formed linearly on the substrate so as to surround the inner electrode; and a resistor arranged to electrically connect the inner electrode and the outer electrode, which generates heat when electricity is passed through it.

2. The heating device according to claim 1, wherein the resistor is disposed so as to completely surround the predetermined region.

3. The heating device as described in claim 2, wherein the outer electrode is arranged so that the tip and base ends of the linear portion surrounding the inner electrode are sandwiched with the same spacing between them and the lead-out portion of the linear portion of the inner electrode that is drawn out from the base end toward the specified region.

4. The heating device according to claim 1, wherein the inner electrode is disposed so as to surround the entire periphery of the predetermined region.

5. The heating device according to claim 1, wherein the outer electrode is formed to surround the inner electrode while maintaining a predetermined distance therebetween.

6. The heating device according to claim 1, wherein the resistor is disposed so as to cover the area between the inner electrode and the outer electrode, and has a plurality of slits.

7. The heating device according to claim 1, wherein said resistor has a positive temperature coefficient.

8. The heat generating device according to claim 1, wherein said inner electrode and said outer electrode each have a plated portion having an intermediate layer containing palladium disposed between a lower layer containing nickel and an upper layer containing gold.

9. An imaging device having a heat generating device according to claim 1 disposed relative to a lens.

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