Imaging device

Abstract

To provide an imaging apparatus that improves heating efficiency of a heating unit to reduce power consumption.SOLUTION: An imaging apparatus (100) has: a window part (140); an imaging unit (200) that photoelectrically converts an optical image obtained through the window part (140); a heating unit (150); and a moving unit (160) that can move the heating unit (150) to a first position and a second position. At the first position, the heating unit (150) is not in contact with the window part (140), and at the second position, the heating unit (150) is in contact with the window part (140).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an imaging device.

Background Art

[0002] Network cameras are assumed to be installed in various environments such as outdoors and cold regions of vehicles. For this reason, in the camera window of the network camera, there is a possibility that the shooting range may be blocked due to the occurrence of dew condensation, snow adhesion, icing, etc., and a desired video cannot be recorded. To avoid this, a network camera equipped with a heater (heating unit) for heating the camera window is known. The heater keeps the camera window at a high temperature with a high amount of electric power in order to melt snow and ice even in sub-zero environments. On the other hand, to prevent dew condensation, it may not be necessary to use as much electric power to keep the camera window at a high temperature.

[0003] Patent Document 1 discloses a camera housing for housing a television camera, in which a fog-proof window is provided as a shooting window, in which window members are arranged at least doubly at a predetermined interval and the space between the multiple window members is sealed to form a heat-insulating layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the camera housing disclosed in Patent Document 1, a fixed heat-insulating layer is arranged between the heater and the camera window. For this reason, in order to heat the camera window with the heater, it is necessary to heat the camera window through the heat-insulating layer. To not only prevent dew condensation but also melt snow and ice, it is necessary to keep the camera window at a high temperature. However, since the heat-insulating layer has a low thermal conductivity, a large amount of power consumption is required to heat the camera window to a high temperature.

[0006] Therefore, an object of the present invention is to provide an imaging device that improves the heating efficiency by a heating unit and consumes less power.

Means for Solving the Problems

[0007] An imaging device according to an aspect of the present invention includes a window portion, an imaging unit that photoelectrically converts an optical image obtained through the window portion, a heating unit, and a movable unit capable of moving the heating unit between a first position and a second position. The The movable part moves the heating part to the first position where there is no first in the case of temperature , the heating unit is contacts the window portion such temperature, and when the temperature is higher than the first temperature , the the temperature is higher than the first temperature second in the case of temperature , the heating unit is is in contact with the window portion the heating part is moved to the second position .

[0008] Other objects and features of the present invention will be described in the following embodiments.

Effects of the Invention

[0009] According to the present invention, it is possible to provide an imaging device that improves the heating efficiency by a heating unit and consumes less power.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, as an example of an imaging device, a network camera will be described as an example, but the present invention is not limited thereto, and the present invention is also applicable to other imaging devices.

[0012] First, referring to FIG. 1, the external configuration of the imaging device (network camera) 100 in this embodiment will be described. FIG. 1 is an external view of the imaging device 100. The imaging device 100 is capable of shooting and recording video. The imaging device 100 has a housing composed of a top cover 110 and a bottom cover 130. The top cover 110 and the bottom cover 130 can each be manufactured by resin molding such as metal die casting or polycarbonate. The bottom cover 130 is provided with installation holes and is fixed to a vehicle or the like using screws or the like. The top cover 110 and the bottom cover 130 are fastened to each other with screws or the like.

[0013] The camera window (window portion) 140 is arranged so as to close the opening 110a which is the shooting range of the top cover 110, and plays a role of protecting the lens unit (optical system) and other components housed inside the housing from impact and dust. The camera window 140 is fixed to the top cover 110 by adhesion or the like. When shooting video, since shooting is performed through the camera window 140, the camera window 140 is treated as an optical component, and transparency and dimensional accuracy are important. The camera window 140 is made of, for example, glass or transparent polycarbonate.

[0014] Next, referring to FIG. 2, the internal configuration of the imaging device 100 will be described. FIG. 2 is a cross-sectional view of the imaging device 100. Inside the housing of the imaging device 100, in order from the outside of the housing, a camera window 140, a heater (heating unit) 150, a first holder (first holding unit) 170, a movable member (movable part) 160, and a second holder (second holding unit) 180 are arranged.

[0015] The heater 150 is configured, for example, by combining a heating member with a transparent plate, and the entire heater 150 is heated by energizing the heating member. Examples of the transparent plate include glass and polycarbonate resin. Examples of the heating member include a configuration in which an FPC heater, a rubber heater, etc. are bonded outside the imaging range of the transparent plate surface, and a configuration in which a heating wire pattern that is difficult to visually recognize is provided on the back surface of the transparent plate, and the entire transparent plate is heated by energizing the pattern. The heater 150 is electrically connected to a control board 300 described later using an FPC or a wire. The first holder 170 holds the heater 150 in a state of covering the edge of the heater 150. The second holder 180 movably holds the first holder 170. The second holder 180 is fixed to the housing with screws or fixing members. The first holder 170 and the second holder 180 are manufactured by resin molding such as polycarbonate or PBT, for example.

[0016] Also, inside the housing, an imaging unit 200 in a substantially spherical shape is arranged. The imaging unit 200 is composed of a lens unit (optical system) 220, a lens holder 230, an imaging board 240 provided with an imaging element, and a lens cover 210, and photoelectrically converts the optical image obtained through the camera window 140. The lens unit 220 is screwed and held by the lens holder 230, and the position can be adjusted in the optical axis direction to adjust the focus. The imaging board 240 is fixed to the lens holder 230 by adhesion or the like. The lens holder 230 is gripped and fixed by the lens cover 210.

[0017] In front of the lens cover 210, an opening for video shooting is formed. Behind the lens cover 210, a hole for passing the wire 250 or the like is formed. The lens cover 210 can be manufactured by resin molding such as metal die-casting or polycarbonate. The imaging unit 200 is held so as to be covered by the cover pressing member 260 and the bottom cover 130, and can perform tilt and rotation operations. The cover pressing member 260 is continuously open from the horizontal position to the vertical position which is the shooting range. Thereby, the range of the tilt operation is restricted. Also, the cover pressing member 260 is fixed so as to be pan rotatable, and the pan operation of the lens unit 220 is possible. The cover pressing member 260 can be manufactured by resin molding such as polycarbonate.

[0018] Also, inside the housing, a control board (control unit) 300 is accommodated. The control board 300 is responsible for the control functions of the entire imaging device 100, such as control of the heater, power supply, camera control, and connection to the network. The control board 300 and the imaging board 240 are electrically connected by the wire 250 or the like. A temperature sensor is mounted on the control board 300 or the imaging board 240, and the control board 300 controls the heater 150 based on the temperature detected by the temperature sensor. The imaging board 240 converts the light received through the camera window 140 and the lens unit 220 into an electrical signal (video data). The electrical signal converted by the imaging board 240 is transmitted to the control board 300. The control board 300 records the received video data or distributes it on the network.

[0019] Next, with reference to FIG. 3, the peripheral structure of the heater 150 will be described in detail. FIG. 3 is an exploded view of the main part of the imaging device 100 (the peripheral part of the heater 150). The top cover 110, the first holder 170, and the second holder 180 have an opening in the shooting range of the imaging unit 200. The heater 150 is fixed to the first holder 170 by double-sided tape or adhesion or the like, and has an integrated structure with the first holder 170.

[0020] The first holder 170 has an edge portion (frame portion) 177 that covers the edge of the heater 150. The height of the edge portion 177 (the horizontal length in FIG. 3, that is, the direction perpendicular to the surface of the camera window 140) is lower than the height of the heater 150 (the horizontal thickness in FIG. 3). Therefore, when the first holder 170 holds the heater 150, the heater 150 protrudes beyond the edge portion 177 (protrudes to the left side in FIG. 3).

[0021] A first guide portion 175 is formed on the first holder 170. A second guide portion 185 is formed on the second holder 180. The first guide portion 175 has a protruding shape and fits into the slit shape of the second guide portion 185. Thereby, the direction in which the first holder 170 and the heater 150 move is restricted in the direction perpendicular to the surface of the camera window 140 (the horizontal direction in FIG. 3). With such a configuration, the heater 150 and the camera window 140 become parallel, and the camera window 140 and the heater 150 can be brought into contact uniformly. As a result, the camera window 140 is heated uniformly, and dew condensation and freezing over the entire imaging range can be prevented.

[0022] In the present embodiment, the first guide portion 175 and the second guide portion 185 are arranged at the short sides of each holder frame, but are not limited thereto, and may be arranged at the long sides or the four corners of each holder frame. Also, in order to restrict the position and rotation, it is desirable that the first guide portion 175 and the second guide portion 185 are each composed of at least two locations. The pressing member (pressing portion) 190 is held by the top cover 110 and is arranged in a state of pressing the first holder 170 toward the inside of the housing. Thereby, vibration is prevented from causing the first holder 170 to vibrate within the second holder 180. The pressing member 190 is made of an elastic member such as silicon rubber or a leaf spring.

[0023] Here, the electric heating method (heating method) of the heater 150 will be described. The control board 300 supplies current to the heater 150 based on information from temperature detection means such as a temperature sensor. Since the heater 150 has an electrical resistance, it generates heat overall due to the current received from the control board 300. The control board 300 has a plurality of target values for the heating temperature of the heater 150. For example, when the outside air temperature is below freezing, the time for supplying current to the heater 150 is lengthened so that the heater 150 reaches a temperature at which it can melt ice and snow. On the other hand, when it is not below freezing but there is a possibility of condensation occurring, the heating of the heater 150 is weakened by shortening the time for supplying current to the heater 150. Also, in a situation where heating is not necessary, no current is supplied. The heat of the heater 150 generated by the current supply from the control board 300 is transmitted to the camera window 140. As a result, the entire camera window 140 is warmed, and condensation, snow adhesion, and icing in the shooting range can be prevented.

[0024] To improve the heating efficiency of the heater 150, it is preferable that the first holder 170 and the second holder 180 are made of a heat-resistant resin with a low thermal conductivity. Thereby, the heat of the heater 150 can be concentrated on the camera window 140 without escaping to the housing. Also, to make the temperature distribution of the camera window 140 uniform, it is preferable to use a glass material with a high thermal conductivity for the material of the camera window 140. Also, to withstand temperature changes and external impacts, it is preferable to employ tempered glass with a thickness of about 5 mm.

[0025] The movable member 160 is disposed between the first holder 170 and the second holder 180, and is fixed to the bottom surface of the frame of the second holder 180 by adhesion or the like. The movable member 160 is made of a bimetal or the like and deforms according to temperature. A bimetal is formed by bonding two metal plates having different coefficients of thermal expansion, and is generally used in a thermometer, a thermostat, or the like. Since the movable member 160 is disposed under the heating member of the heater 150, the heat of the heater 150 is easily transmitted. When the heater 150 becomes high temperature (when the temperature of the heater 150 rises), heat is transmitted to the movable member 160, and the movable member 160 deforms so as to warp. As a result, the movable member 160 presses the first holder 170 in a direction approaching the camera window 140 (left direction in FIG. 3). The pressing force of the movable member 160 is set to be larger than the reaction force of the pressing member 190. The movable member 160 is composed of a plurality of members, and is preferably disposed evenly near each guide portion and within the frame of each holder.

[0026] Next, with reference to FIGS. 4(a) and 4(b), the movement of the heater 150 in the imaging device 100 will be described. FIGS. 4(a) and 4(b) are explanatory views of the movement of the heater 150. FIG. 4(a) shows a state in which a space 400 exists between the camera window 140 and the heater 150, that is, a state in which the heater 150 is not in contact with the camera window 140 (first position). This state is assumed to be a mode for preventing dew condensation, and the time during which current is supplied to the heater 150 is short and the temperature of the heater 150 is low (first temperature). Therefore, the deformation of the movable member 160 is small and is close to a flat plate shape. Accordingly, the amount of pressing of the movable member 160 against the first holder 170 is also small. On the other hand, by the pressing member 190, the first holder 170 and the heater 150 are pressed in the direction of the inside of the housing with a weak force. As a result, a heated space 400 is formed between the heater 150 and the camera window 140. The space 400 serves as a heat insulating layer.

[0027] Here, the principle of dew condensation is explained. When the outside air is in a low-temperature state, the camera window 140 is cooled by the outside air. When the imaging device 100 is powered on at this time, the inside of the housing becomes warmer than the outside air temperature due to the heat of the imaging substrate 240 and the control substrate 300. Then, the moisture absorbed by the substrates and components is released into the housing as water vapor. Since the camera window 140 is cooled by the outside air, the air near the inside of the camera window 140 is locally cooled. As a result, the water vapor inside the housing locally exceeds the saturated water vapor amount and dew condensation occurs by solidification.

[0028] In the state of Fig. 4(a), a heated space 400, that is, a heat insulation layer, is formed inside the camera window 140. Since the volume of this heat insulation layer is small, the amount of water vapor it contains is also very small compared to the inside of the housing. Also, since it is heated by the heater 150, dew condensation does not occur inside the heat insulation layer. And since the amount of air that needs to be heated by the heater 150 is small, the amount of electric power supplied to the heater 150 may be small. Also, since the thermal conductivity of air is low, the heat insulation layer has a function of making it difficult for the temperature of the outside air to be transmitted into the housing. Therefore, it prevents the heater 150 and the inside of the housing from being locally cooled through the camera window 140 by the outside air.

[0029] Figure 4(b) shows the state where the heater 150 is in contact with the camera window 140 (second position). This state assumes a mode of removing ice and snow in a sub-zero environment, where the heater 150 is supplied with current for a long time and the temperature of the heater 150 is high (a second temperature higher than the first temperature). Therefore, the deformation of the movable member 160 is large and it takes an arcuate shape. Accordingly, the pressing amount against the first holder 170 is large. The pressing member 190 presses the first holder 170 weakly inside the housing. However, since the pressing force of the movable member 160 is stronger (the pressing force of the pressing member 190 is weaker than that of the movable member 160), the first holder 170 and the heater 150 move toward the camera window 140 side. Then the heater 150 and the camera window 140 come into contact (abut). To remove ice and snow, it is necessary to raise the temperature of the outside of the housing of the camera window 140 to 0°C or higher. In the state of Figure 4(b), since the temperature of the heater 150 is high and the heater 150 is in contact with the camera window 140, the electrothermal efficiency is high. Therefore, even when the outside air temperature is below freezing, it is possible to sufficiently raise the temperature of the outside of the camera window 140 and prevent the adhesion of ice and snow.

[0030] As described above, the movable member 160 can move the heater 150 to the first position and the second position. In the first position, the heater 150 is not in contact with the camera window 140, and in the second position, the heater 150 is in contact with the camera window 140. Preferably, when the temperature is the first temperature, the movable member 160 moves the heater 150 to the first position, and when the temperature is a second temperature higher than the first temperature, the movable member 160 moves the heater 150 to the second position.

[0031] According to the present embodiment, by automatically moving the heater 150 by the movable member 160 according to the temperature, it is possible to efficiently heat the camera window 140 and save power in each of the dew condensation prevention and ice and snow removal times. Therefore, according to the present embodiment, it is possible to provide an imaging device with high heating efficiency by the heating unit and low power consumption.

[0032] Note that in this embodiment, the housing is composed of two parts, the top cover 110 and the bottom cover 130, but it may also be composed of three or more parts. Also, in this embodiment, the top cover 110 and the bottom cover 130 may be fixed using claw fitting or adhesion. Also, in this embodiment, the connection between the control board 300 and the imaging board 240 may be electrically connected using a flexible board, a flat cable, a thin wire coaxial cable, or a relay board. Also, in this embodiment, the connection between the heater 150 and the control board 300 may be made using a relay board. Also, in this embodiment, the heater 150 may use a film heater with a transparent imaging range. Also, in this embodiment, the movable member 160 may be made of a member that deforms upon energization, such as a motor, a magnet, or an artificial nerve. Also, in this embodiment, the camera window 140 may use acrylic resin, sapphire glass, or the like. Also, in this embodiment, the first guide portion 175 and the second guide portion 185 may be formed using a pin shape or outer shape fitting instead of a protrusion and a slit. Also, in this embodiment, the pressing member 190 may be omitted by fixing both ends of the movable member 160 to the first holder 170 and the second holder 180, respectively.

[0033] As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

Explanation of Reference Numerals

[0034] 100 Imaging device 140 Camera window (window portion) 150 Heater (heating portion) 160 Movable member (movable part) 200 Imaging unit

Claims

1. A window portion, an imaging unit that photoelectrically converts an optical image obtained through the window portion, a heating unit, and a movable unit capable of moving the heating unit between a first position and a second position, wherein when the temperature is a first temperature, the movable unit moves the heating unit to the first position where the heating unit is not in contact with the window portion, and when the temperature is a second temperature higher than the first temperature, the movable unit moves the heating unit to the second position where the heating unit is in contact with the window portion. An imaging device characterized by this.

2. A housing, a first holding unit that holds the heating unit, and a second holding unit that is held by the housing and movably holds the first holding unit, wherein the movable unit is disposed between the first holding unit and the second holding unit, and the heating unit is movable between the first position and the second position by the movement of the first holding unit by the movable unit. The imaging device according to claim 1, characterized by this.

3. At the first position, a space is formed between the heating unit and the window portion, and at the second position, the heating unit is pressed against the window portion by the movable unit. The imaging device according to claim 2, characterized by this.

4. The first holding unit and the second holding unit are open in the imaging range of the imaging unit. The imaging device according to claim 2 or 3, characterized by this.

5. The first holding unit has an edge portion that covers an edge of the heating unit, and in a direction perpendicular to the surface of the window portion, the height of the edge portion is lower than the height of the heating unit. The imaging device according to any one of claims 2 to 4, characterized by this.

6. The movable unit deforms according to temperature, and when the temperature of the heating unit rises, the movable unit moves the first holding unit closer to the window portion. The imaging device according to any one of claims 2 to 5, characterized by this.

7. The first holding unit has a first guide portion, the second holding unit has a second guide portion that fits with the first guide portion, and the first holding unit is movable in a direction perpendicular to the surface of the window portion with respect to the second holding unit. The imaging device according to any one of claims 2 to 6, characterized by this.

8. The imaging device according to any one of claims 2 to 7, further comprising a pressing portion disposed between the first holding unit and the housing, characterized by this.

9. The imaging device according to claim 8, wherein the pressing force of the pressing portion is weaker than the pressing force of the movable portion.

10. The imaging device according to any one of claims 2 to 9, wherein the window portion is fixed to the housing so as to close an opening of the housing.

Images