JP7527872B2 - Heater units and their applications - Google Patents

Description

The present invention relates to a heater unit for removing condensation, ice, frost, and water droplets that have adhered to, for example, a camera unit in a vehicle, and for preventing fogging, dew, ice, and frost from adhering, and to a camera unit equipped with this heater unit.

Nowadays, various camera units are used as devices for automatic driving and driving assistance to detect the presence or absence of other vehicles and obstacles in front of the vehicle. In addition to conventional mirrors, there are also devices that capture images using camera devices and display the images on an in-vehicle monitor as a means of visually checking the sides and rear of the vehicle. There are also devices called drive recorders that capture images of accidents, thefts, etc., and use them as materials for subsequent on-site investigations. Some of these are installed inside the vehicle cabin, and some are installed outside the vehicle cabin. Here, if the humidity in the vehicle cabin or the surrounding atmosphere is high, if the temperature difference between the camera unit and the surrounding atmosphere is large, or if the temperature of the lens is below the dew point, condensation may form on the lens surface, causing the lens to become cloudy or dew to adhere to it. In addition, if the temperature of the surrounding atmosphere is below 0°C, frost or ice may adhere to the lens. In order to prevent these, some camera units are equipped with a heater unit for heating the lens near the lens of the camera unit. The heat emitted from this heater unit melts and evaporates any fog, dew, frost, ice, etc. that has adhered to the lens, removing them. This heat can also prevent the lens from dropping below the dew point, preventing condensation. This results in clearer images taken by the camera unit. For example, see Patent Documents 1 and 2 for examples of such technology.

Technologies related to the present invention include, for example, Patent Documents 3 and 4.

JP 2004-325603 A: Kyocera WO2019/225745: Maxell JP2019-114330A: Nifco, Kurabe JP2019-145498A: Kurabe

The lens in an in-vehicle camera unit is a small component with a diameter of less than 10 mm, and the space around the lens is reduced to the limit, so the heater unit attached to it is similarly small. In such a case, it is difficult to increase the resistance value of the heater unit with a normal conductor pattern design, and unless a dedicated low-voltage power supply is prepared, the amount of power required will be large, resulting in overheating. Overheating will cause thermal distortion in the lens and the lens holding members, causing errors in the optical design.

The present invention was made to solve these problems with the conventional technology, and its purpose is to provide a heater unit that does not overheat even when it is small in size, and that contributes to power saving and space saving, and a camera unit equipped with the heater unit.

In order to achieve the above-mentioned object, the heater unit according to the present invention is a heater unit consisting of a planar substrate and a conductor formed on the substrate, and has a lead portion and a plurality of annular heating portions, wherein the conductor in the lead portion and the conductors in the plurality of annular heating portions are continuous, and the substrate in the lead portion and the substrate in the plurality of annular heating portions are continuous.
It is also possible that the boundary between one annular heating portion and another annular heating portion among the plurality of annular heating portions is bent, and the one annular heating portion and the other annular heating portion are arranged overlapping each other.
It is also conceivable that the conductor in the annular heating portion has a folded portion and forms a ring shape with a plurality of wires.
It is also possible that the conductors in the lead portion and the plurality of annular heating portions are all connected in series.
A camera unit according to the present invention has the above heater unit disposed in the vicinity of the lens.

According to the present invention, by having a plurality of continuous annular heating parts, the total length of the conductor wire is increased, and the required resistance value can be obtained. Therefore, it is possible to design a heater that does not overheat.
In addition, by folding and overlapping the boundaries between the annular heating portions, it is possible to contribute to space saving.

FIG. 2 is a plan view showing a configuration of a heater unit according to the embodiment of the present invention. FIG. 13 is a plan view showing the configuration of a heater unit according to another embodiment of the present invention. FIG. 13 is a plan view showing the configuration of a heater unit according to another embodiment of the present invention. FIG. 13 is a plan view showing the configuration of a heater unit according to another embodiment of the present invention. FIG. 13 is a plan view showing the configuration of a heater unit according to another embodiment of the present invention. FIG. 13 is a plan view showing the configuration of a heater unit according to another embodiment of the present invention. 1 is a cross-sectional view showing an overview of a camera unit according to the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, as shown in Fig. 1, there is a substrate 3 made of a polyamideimide film having a thickness of 28 µm. The substrate 3 used in the present invention is a film made of a conventionally known polymeric material such as a synthetic resin, and, in addition to a polyamideimide film, for example, a PET film (polyester film), a polyimide film, a polyphenylene sulfide film, or the like is preferably used.

On this substrate 3, a conductor 1 having a thickness of 30 μm is formed by etching a foil of stainless steel (SUS304). As the conductor 1, in addition to stainless steel, metals such as copper, copper alloys, aluminum, and nickel chrome are preferably used. Carbon or conductive resin may also be used. These are patterned by processes such as etching and punching, and obtained as a sheet of foil. The conductor pattern may also be formed by methods such as vapor deposition and coating. In FIG. 1, the conductor 1 is indicated by the blackened area.

The heater unit of the present invention has a lead portion 7 and multiple annular heating portions 5a, 5b, which are formed continuously with the lead portion 7. The portion of the conductor 1 that is present at the lead portion 7 has a low resistance value due to its wide width, and is therefore a portion that does not actually generate heat. The portion of the conductor 1 that is present at the annular heating portions 5a, 5b has a high resistance value due to its narrow width, and is a portion that contributes to heat generation. The conductor 1 also has a folded portion 1a, which is formed into a ring shape by multiple lines (two lines in this embodiment). By providing such a folded portion, the total length of the conductor 1 is increased, and the resistance value of the conductor 1 can be increased.

The substrate 3 is slightly wider than the conductor 1 so as to cover the conductor 1, and the portions of the substrate 3 that are present in the annular heating portions 5a and 5b are annular and lacking a central portion. In this embodiment, the conductor 1 is sandwiched between two substrates 3, and the conductor 1 is insulated by the substrates 3.

Multiple annular heating portions (two annular heating portions 5a, 5b in this embodiment) are formed. The two annular heating portions 5a, 5b can be folded at the boundary portion 5f between them, and the two annular heating portions 5a, 5b can be used by overlapping them. When the two annular heating portions 5a, 5b are overlapped, it is preferable that the folded portions 1a of the heating element 1 in each annular heating portion 5a, 5b are misaligned and do not overlap. In this embodiment, the lead portion 7, the conductor 1 in the annular heating portion 5a, and the annular heating portion 5b are all connected in series, and the resistance value is 8.14 Ω.

The substrate 3 may also be formed with an adhesive layer (not shown) for bonding to other members. Various materials can be used to form the adhesive layer, but the material is designed according to the environment in which the heater unit 31 is used and the heat generation characteristics of the heater unit 31. In particular, when the heater unit 31 is installed in the camera unit, it is preferable that the adhesive layer does not contain any substances that volatilize when heated.

The conductor 1 and substrate 3 obtained as described above have a pattern shape as shown in FIG. 1. Here, two ends of the conductor 1 in the lead portion 7 are exposed and connected to lead wires 25, which are then connected to a power source, a temperature control device, etc. Temperature control devices include not only temperature control circuits, but also, for example, thermostats, thermistors, temperature fuses, etc.

Such a heater unit 31 can be attached in the camera unit. An example of a camera unit will be described with reference to FIG. 7. FIG. 7 is a schematic cross-sectional view of a camera unit 60, in which a first lens 61, a second lens 62, and a lens group 63 are arranged in a lens barrel 65, and an optical filter 66 is arranged at the bottom of the lens barrel 65, which are arranged in a camera case 69. An imaging board 67 including an image sensor is arranged at the bottom of the camera case 69 so as to be perpendicular to the optical axis of the first lens 61, the second lens 62, and the lens group 63. An O-ring 68 is arranged at the portion where the first lens 61 and the lens barrel 65 contact each other and at the portion where the lens barrel 65 and the camera case 69 contact each other to prevent water or the like from entering the camera unit. The heater unit 31 is installed so that the annular heating portion 5a and the annular heating portion 5b are overlapped and are disposed on the periphery of the first lens 61, and is sandwiched between the first lens 61 and the second lens 62. The lead portion 7 and the lead wire 25 of the heater unit 31 pass through a hole formed in the lens barrel 65, between the lens barrel 65 and the camera case 69, and are connected to a predetermined power source.

When the humidity in the vehicle cabin or the surrounding atmosphere is high, when the temperature difference between the camera unit and the surrounding atmosphere is large, or when the temperature of the surrounding atmosphere is below 0°C, fogging, dew, frost, ice, etc. may adhere to the surface of the first lens. This fogging, dew, frost, ice, etc. may scatter light and hinder clear photography by the camera unit 60. For this reason, the heater unit 31 is installed between the first lens 61 and the second lens 62, and the first lens 61 is heated by the heat emitted from the heater unit 31, thereby removing the fogging, dew, frost, and ice. In addition, the inside of the lens barrel 65 is heated by the heat from the heater unit 31, and the inside of the lens barrel 65 can be kept at a temperature close to room temperature, especially in cold weather. This can also prevent the optical characteristics from changing due to thermal contraction caused by cooling of the first lens 61, the second lens 62, the lens group 63, and the lens barrel 65.

The present invention is not limited to the above-mentioned embodiment. For example, the conductor 1 may be wire-shaped instead of foil-shaped. As such a wire-shaped conductor 1, various conductor wires can be used, such as silver-containing copper alloy wire, tin-containing copper alloy wire, soft copper wire, copper-nickel alloy wire, tin-plated or silver-plated copper alloy wire, nickel-chromium alloy wire, iron-chromium alloy wire, stainless steel wire, aluminum alloy wire, carbon wire, etc. Furthermore, these conductor wires may be coated with an insulating film. For more information, refer to the above-mentioned Patent Document 4.

In this embodiment, the conductor 1 is sandwiched between two base materials 3 and insulated, but the conductor 1 may not be insulated by the base materials 3 and one side of the conductor 1 may be exposed. For example, if the heater unit 31 is installed in a completely sealed location, waterproofing is not necessary and there is no need to completely insulate the conductor 1. However, in this case, when folding at the boundary portion 5f, it is necessary to fold the conductor 1 with the exposed side facing outward, rather than folding with the exposed side facing inward. In addition, in the case where the conductor 1 is sandwiched between two base materials 3, it is preferable that the base material 3 is made of a transparent material, because if an abnormality such as a break occurs in the conductor 1, it can be visually confirmed.

In this embodiment, there are two annular heating parts 5a and 5b, but there may be three or more annular heating parts, and the annular heating parts may be connected in various ways other than the linear shape of this embodiment. For example, as shown in FIG. 2, three annular heating parts 5a, 5b, and 5c may be connected in a straight line; as shown in FIG. 3, the connection direction of the annular heating part 5a and the annular heating part 5b is bent at 90 degrees from the connection direction of the lead part 7 and the annular heating part 5a; as shown in FIGS. 4 and 5, two annular heating parts 5b and 5c are connected to the annular heating part 5a. In FIGS. 2 to 5, the conductor 1 is indicated by a blackened area.

In addition, as shown in FIG. 6, the conductor 1 may not have a folded portion 1a in the annular heating portion, and may instead form a ring shape with a single line. In FIG. 6, the conductor 1 is shown as a black portion. The folded portion 1a may be folded not only once, but two or more times. In the above embodiment, the annular heating portion is generally annular, but may also be other shapes, such as a polygon such as a triangle or a square, an ellipse, or a sector.

In this embodiment, the conductor 1 has a straight line shape at the boundary 5f between the two annular heating portions 5a, 5b, but the boundary 5f does not have to have such a shape, and may have a shape in which the annular conductors 1 come into contact with each other, as shown in FIG. 3. Also, as shown in FIG. 5, it is also conceivable to widen the width of the conductor 1 at the boundary 5f, making it a portion that does not contribute to heat generation.

In order to increase the efficiency of heat conduction to the heated part, it is also possible to install an insulating sheet made of foamed resin or the like on the side opposite to the side in contact with the heated part. In this case, it is also possible to use an insulating sheet that combines multiple materials with different properties such as insulating properties, heat resistance, shock absorption, and appearance. It is also possible to install a heat equalizing member to make the heat generated from the conductor 1 uniform. For example, foils of copper, copper alloy, aluminum, stainless steel, etc. can be used as the heat equalizing member.

In the above embodiment, the heater unit 31 is disposed between the first lens 61 and the second lens 62 in the camera unit 60, but it may be disposed in other locations. For example, it may be disposed in various locations, such as around the first lens 61, the inner surface of the lens barrel 65, or the inner surface of the camera case 69.

The heater unit 31 of the present invention can be applied not only to camera units but also to various sensor units. For example, it can be used in radar units, laser lidar units, ultrasonic sensor units, etc. More specifically, it is also conceivable to attach the heater unit to a radome, which is the cover for the radar unit.

As described above in detail, according to the present invention, it is possible to obtain a heater unit that has sufficient safety functions and also contributes to power saving and space saving. Such a heater unit can be suitably used as a heat source for, for example, home heating appliances, heating devices for automobile interiors, industrial heating devices, various snow removal and ice melting devices, anti-fogging devices, heating and cooking appliances, etc. Furthermore, it can be used not only as a heater for conductive heat transfer that is used in contact with the object to be heated, but also as a heater for radiant heat transfer that is installed at a distance from the object to be heated.

1 Electrical conductor 1a Folded portion 3 Base material 5a, 5b, 5c Ring-shaped heat generating portion 7 Lead portion 31 Heater unit

Claims (5)

A heater unit including a planar substrate and a conductor formed on the substrate,
A lead portion and a plurality of annular heating portions,
the annular heating portion is made of the base material having a shape lacking a central portion and the conductor,
a heater unit in which the conductor in the lead portion and the conductors in the plurality of annular heat generating portions are continuous, and a base material in the lead portion and a base material in the plurality of annular heat generating portions are continuous. The heater unit according to claim 1, wherein the plurality of annular heating portions are folded at the boundary between one annular heating portion and another annular heating portion, and the one annular heating portion and the other annular heating portion are arranged overlapping each other. The heater unit according to claim 1 or 2, wherein the conductor in the annular heating section has a folded portion and forms a ring shape with multiple wires. A heater unit according to any one of claims 1 to 3, in which the conductors in the lead portion and the multiple annular heating portions are all connected in series. A camera unit in which the heater unit according to any one of claims 1 to 4 is disposed near the lens.

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