Vehicle camera with surface heating part

Abstract

To provide a camera equipped with a compact heating part that reliably prevents formation of frost or condensation and requires just a small installation space in the camera.SOLUTION: According to an embodiment of the present invention, a camera for a vehicles is provided, the camera comprising a housing, at least one optical element, and a circuit board, the at least one optical element being located in or on the housing, the circuit board comprising at least one image sensor and a surface heating part for heating the at least one optical element.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a camera equipped with a surface heating unit, particularly a camera for a vehicle, for example, a commercial vehicle.

Background Art

[0002] Camera systems and image capturing systems are each used as devices for peripheral vision beside conventional mirrors or additionally or alternatively to these mirrors in vehicles, particularly commercial vehicles, for peripheral vision. A camera system usually comprises an image capturing unit such as a camera that continuously captures the surroundings of the vehicle as (video) data. The (video) data captured by the image capturing unit is processed and then transmitted to a playback unit arranged in the driver's cab if necessary, and this playback unit permanently and in real time displays the (video) data to the driver, and in that case fades in additional information about the imaged parts of the surroundings, such as signs of a collision or distance.

[0003] The camera of a camera system is usually mounted outside the vehicle. Therefore, the camera is exposed to the weather at the vehicle site. In particular, when the temperature is low, frost or condensation may occur on the optical element and the cover glass of the optical element respectively, which may affect the imaging function of the camera. Furthermore, parts repeatedly exposed to low temperatures may have a change in material and may become more prone to damage.

[0004] To avoid the occurrence of frost or condensation on the optical element of the camera, it is known to heat the camera. So far, as disclosed in German Patent Invention No. 102013020894, for example, heating elements in the form of discrete resistors are arranged at specific positions on the circuit board. However, these heating elements require a relatively large installation space in the camera. Therefore, there is a shortage of installation space for other components in the camera, or if other components are still installed, the entire camera becomes larger, resulting in a drawback in the required installation space in the vehicle.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of such points, and an object thereof is to provide a camera having a small heating unit that prevents the occurrence of frost and dew with high reliability, while requiring a small installation space in the camera.

Means for Solving the Problems

[0006] This object is solved by a camera having the features of claim 1 and a vehicle having the features of claim 18. Preferred embodiments are shown in the dependent claims.

[0007] The present invention is based on the idea of providing a vehicle, particularly a camera for a commercial vehicle, provided with a surface heating unit. The surface heating unit is at least partially mounted / applied on a circuit board that also mounts an image sensor. The surface heating unit is made of a heat conductive material and extends over a certain area of the circuit board. Here, the area refers to a geometric shape, specifically a portion that spreads flat in the longitudinal and lateral directions. In particular, the surface heating unit is defined such that the extension in each of the length direction and the width direction is many times larger than the extension in the thickness direction. In this regard, the extensions in the length direction and the width direction of the surface heating unit are determined such that, when arranged on the circuit board, they cross a plane substantially parallel to the plane that crosses the length direction and the width direction of the circuit board.

[0008] In the surface heating unit, since the heat generating surface is larger than that of a conventional heating element, heat is continuously input to the optical element of the camera through a larger surface. At the same time, since the spread in the thickness direction of the surface heating unit is very small, only a very small installation space is required in the longitudinal direction of the camera. The longitudinal direction of the camera is defined as the direction in which the plug of the camera, one or more circuit boards, and the optical element are arranged in a row.

[0009] For example, the surface heating part can be made of a thin metal sheet adhered on a circuit board. Alternatively, the surface heating part may be a thin metal layer sprayed, cast, vapor-deposited, or zinc-plated on the circuit board. However, preferably, the surface heating part is formed by conductor paths. The conductor paths may each be made of copper material, aluminum, or a copper alloy and an aluminum alloy. Alternatively, the conductor paths can be made of another heat-conductive material. To provide the surface heating part, the conductor paths are respectively arranged and laid out such that, in the case of a single section of the conductor path or a plurality of conductor paths, a plurality of single conductor paths are arranged adjacent to each other on the circuit board. Adjacent to each other here means that there are no other elements between single sections of the conductor paths, but the single sections do not contact each other. For example, the conductor paths can be arranged in a meandering shape. Here, being in a meandering shape means that the conductor paths are respectively arranged in loop parts and winding parts and change direction by approximately 180 degrees at each of two predetermined end positions. Therefore, the conductor paths have a plurality of conductor path portions that run substantially parallel to each other without interruption. The meandering arrangement, in contrast to the spiral arrangement of the conductor paths, has the advantage that since the conductor paths do not function as an antenna, they are not disturbed by the interfering radiation emitted by the electronic devices of the camera and neighboring devices, and electromagnetic compatibility is ensured.

[0010] The heating power of the surface heating part formed by the conductor paths is based on the cross-section and length of the conductor paths and the geometry of the surface heating part, which is called the geometry of the surface heating part and is based on the arrangement of the surface heating part. Resistance is generated by the specific thermal conductivity of the material used for the conductor paths (original notation: specific thermal conductivity) and the cross-sectional area of the conductor paths. Therefore, the resistance can be calculated for a predetermined current or voltage and a predetermined heating power, and as a result, the resistance can be converted into the geometry of an appropriate conductor path.

[0011] To effectively heat the optical element, it is preferable that the conductor paths partially extend around the image sensor. Alternatively, the conductor paths may completely surround the image sensor.

[0012] Since the heating of the camera is mainly performed to avoid the occurrence of frost and dew condensation, it is advantageous for the conductor path to be disposed on the surface of the circuit board on which the image sensor is disposed and facing the optical element accordingly. Alternatively, the conductor path may also be disposed on the surface facing the optical element, and the conductor path may be disposed on both surfaces of the circuit board.

[0013] According to a preferred embodiment, the boundary (outer peripheral boundary) of the outer periphery of the conductor path disposed on the plane substantially corresponds to the outer peripheral dimension of the optical element. Thereby, efficient heat input to the optical element can be ensured.

[0014] Preferably, the conductor path is disposed on a specific circuit board layer, and more preferably, on the circuit board layer on which the image sensor is also disposed. Alternatively, the conductor path may also be disposed on another circuit board layer, for example, an internal circuit board layer or the circuit board layer on the surface facing the surface of the circuit board having the image sensor. Due to the fact that the conductor path is disposed on only one circuit board layer, it is more preferable for the conductor path to have a substantially two-dimensional planar shape in which the conductor path has an extension in the length direction and the width direction but hardly has an extension in the thickness direction.

[0015] As yet another aspect, the conductor path can extend across a plurality of substantially parallel circuit board layers. That is, in the top view of the circuit board, the conductor path has a flat arrangement of adjacent conductor path portions or conductor paths, but in the cross-sectional view of the circuit board, the conductor path is arranged to switch between different parallel circuit board layers. In other words, when the circuit board is cut, the conductor path exists on a plurality of circuit board layers and changes and switches between the circuit board layers respectively. Therefore, the term "surface heating portion" also means that a single section is flatly configured, and thus has very limited extension in the thickness direction of the conductor path. However, as a whole, it must be understood as an arrangement having a configuration at different height levels in the thickness direction of the circuit board while maintaining a dimension that has a flat configuration in the cross-sectional view or the side view and hardly extends in the thickness direction.

[0016] To heat the image sensor and thus avoid image noise, the circuit board layer on which the image sensor is disposed can be removed and separated respectively between the image sensor and the conductor path. That is, there is no heat conductive material between the image sensor and the conductor path. Therefore, it is possible to prevent the heat of the conductor path from being transmitted to the image sensor, and thus improve the highly reliable function of the image sensor. This effect can be amplified when the space exposed from the heat conductive material is filled with a heat insulating material. Alternatively, in addition to removing the circuit board layer, a heat barrier can be provided between the image sensor and the conductor path. The heat barrier is either made of a heat insulating material and serves as a heat insulator, or made of a heat conductive material, such as the material of the conductor path, and serves as heat storage and heat buffer respectively. In order to store and buffer sufficient heat respectively, the heat barrier has a certain heat capacity. Here, the term heat capacity means the ability to receive and store heat. For example, the heat barrier can be configured as a circular and annular shape with a certain spread in the longitudinal direction of the camera and the thickness direction of the conductor path respectively so as to have a certain accumulation of the material for heat energy storage.

[0017] Preferably, the camera includes at least one second conductor path for selectively controlling in response to the heating power requirement. For example, the camera has two conductor paths configured as described above, and these conductor paths can be arranged concentrically with each other around the image sensor or adjacent to each other. During the heating operation, when higher heating power is required, such as in the case of a temperature below the freezing point, only one of the two conductor paths may be turned on in addition to the other conductor path. Alternatively or additionally with respect to the adjustment of the heating power, the cross-section of the conductor path may vary along the extension of the conductor path. For example, the conductor path may have a continuously varying cross-section or may vary only partially with respect to the cross-section.

[0018] To fix the optical element within or to the housing of the camera, a heat conduction element may be provided between the optical element and the housing. Preferably, the heat conduction element is made of a potting material that fixes the optical element within the housing and is made of a heat conductive material. Therefore, the heat of the conductor path can be introduced not only directly into the optical element, but also first introduced into the housing of the camera, and then the heat is introduced into the optical element through the housing of the camera, so that it can also be indirectly introduced into the optical element through the potting material. Thereby, the heating of the optical element can be performed more efficiently and quickly.

[0019] Alternatively or additionally, the optical element can be fixed on the circuit board by an adhesive. The adhesive is preferably made of a heat conductive material so that reliable heat transfer from the conductor path to the optical element is performed.

[0020] Preferably, the camera comprises at least one temperature sensor for adjusting the heating capacity and / or for adjusting the heating time. The temperature sensor serves to detect the temperature state within the camera housing and / or of the optical element, where adjustment of the heating power and / or of the heating time is required depending on the temperature state. For this purpose, the sensor is preferably embedded within the camera housing, for example, within the potting material and / or adhesive, and is preferably arranged at or in the vicinity of the position of the optical element. If the temperature sensor detects, for example, that the temperature within the camera housing has exceeded a specific predetermined value, this result is transmitted to the adjustment unit via the central electronic control unit (ECU), and the adjustment unit reduces or switches off the heating power. Conversely, if the temperature sensor detects that the temperature within the camera housing has fallen below a predetermined temperature threshold, the adjustment unit can also switch on or increase the heating power. Monitoring of the temperature within the camera housing can additionally or alternatively also be initiated by the user (for example, the driver of a vehicle). For this purpose, a user interface such as a user interface with an ON / OFF switch or a user knob is provided within the vehicle, and using this, the user can start or stop the operation of the face heating part. Alternatively or additionally, temperature control within the camera housing can also be performed by presetting the heating time.

[0021] In principle, the operation of the face heating part can occur in relation to the adjustment unit via the ECU in that the temperature sensor detects and reports a temperature value and activates or deactivates the face heating part when the specified temperature value is exceeded or fallen below. Alternatively or additionally, when the outside air temperature is low and condensation or frost formation occurs and a sufficiently good camera image cannot be obtained, the face heating part can also be operated by the user, for example, by a specific operating element provided for this purpose within the passenger compartment of the vehicle.

[0022] In addition to or further to at least one temperature sensor, a current sensor may be provided that detects the current intensity in the conductor path and adjusts the heating power and, if so, the heating time via an adjustment unit when the strength of the current in the conductor path exceeds an allowable value or falls below a required value. The current sensor may be provided within the thermal barrier or on the circuit board. Here too, the manual setting of the heating power and heating time can be performed by the user according to the current strength. For this purpose, the user is notified of the current strength, and the user may adjust the current strength accordingly. Here, in order to avoid damage to the surface heating part and the camera, the user input can be overwritten by the control unit if a harmful adjustment of the heating by the user has been made.

[0023] At least one conductive path is preferably used not only for heating the optical element but also as a power supply line for components arranged on the circuit board such as an image sensor. By using the conductor path as a power supply line at the same time, a voltage drop that must be considered when designing the conductor path occurs.

Brief Description of the Drawings

[0024] Hereinafter, the present invention will be exemplarily described with reference to the accompanying drawings.

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0026] FIG. 1 shows a longitudinal section passing through a vehicle camera 20 having a central axis a-a'. The camera 20 includes a housing 22. Inside the housing 22, an optical element 24 and a plurality of circuit boards 10 are arranged. The optical element 24 is composed of an (objective) lens and a cover glass for protecting the lens. On the circuit board 10 adjacent to the optical element 24 and on the surface facing the optical element 24, an image sensor 16 for recording an image around the vehicle is arranged at the center thereof. On the opposite surface, that is, the surface of the circuit board 10 away from the optical element 24, electrical components necessary for executing the camera function are arranged. The electrical components 14 may be arranged alternatively or additionally on the surface of the circuit board 10 facing the optical element 24. On the circuit board at the position farthest from the optical element 24, connectors 30 for voltage supply and data transmission of the camera are provided. The circuit boards are connected in a conductive manner to each other (not shown). Hereinafter, the direction along the longitudinal axis a-a' in which the circuit board, the image sensor 16, and the optical element 24 are arranged in this order is referred to as the longitudinal direction.

[0027] Around the image sensor 16, that is, on the surface of the circuit board 10 facing the optical element 24, a surface heating portion 17 configured / formed as a conductor path 18 is provided. The outer dimensions of the conductor path 18 substantially correspond to the outer dimensions of the surface of the optical element 24 facing the circuit board 10.

[0028] The optical element 24 is connected to the housing 22 and the circuit board 10 by a potting material 28. The potting material 28 is made of a heat-conductive material based on polyurethane.

[0029] Figure 2 is a perspective view of the circuit board 10 on which the optical element 24 is mounted. As shown in Figure 2, the end face of the optical element 24 facing the circuit board 10 is connected to the circuit board 10, specifically to the conductor path 18, by an adhesive 26 such as an instant adhesive or a two-component adhesive. Similar to the potting material 28, the adhesive 26 is also made of a heat conductive material. Further, as can be seen from Figure 2, the conductor path 18 is arranged to meander around the image sensor 16 (not shown in Figure 2), where the specific winding and the conductor path portion each change the traveling direction by about 180 degrees at a certain position with respect to the image sensor 16.

[0030] Figure 3 is a top view of the circuit board 10 of Figure 1. As shown in Figure 3, the image sensor 16 is arranged approximately at the center of the circuit board 10. However, the position of the image sensor 16 on the circuit board 10 may be off-center, and in principle, it is always necessary to be selected so that the optical element 24 can at least partially display and record the images around the vehicle on the image sensor 16. That is, it is possible but not essential for the optical element 24 to be accurately arranged above the image sensor 16. The conductor path 18 is arranged around the image sensor 16. To avoid the antenna effect of the conductor path 18, the conductor path 18 is arranged to meander around the image sensor 16. The terminal end 19 of the conductor path 18 is also provided on the circuit board 10 and is electrically connected to a power supply (not shown). The image sensor 16 and the conductor path 18 are each applied and provided on the circuit board layer 12. The circuit board layer 12 is made of a heat conductive metal such as copper and forms a copper layer.

[0031] A heat barrier 13 is provided between the image sensor 16 and the conductor path 18. The heat barrier 13 is configured as a closed enclosure, for example, a ring, and completely surrounds the image sensor 16. The heat barrier 13 may be made of a heat insulating material or may be made of a metal such as the same metal as the circuit board layer 12. Instead of or in addition to the heat barrier 13, the circuit board layer 12 between the image sensor 16 and the conductor path 18 may also be omitted. Therefore, if omitted, in addition to the heat barrier 13, the heat of the conductor path 18 being transmitted to the image sensor 16 through the circuit board layer 12 is avoided.

[0032] To heat the camera 20, the conductor path 18 is energized, and as a result, the conductor path 18 is heated. Since the conductor path 18 is spatially close to the optical element 24, the heat of the conductor path 18 is transmitted to the optical element 24 by heat convection through the air. Further, the thermal energy of the conductor path 18 is transmitted directly from the conductor path 18 to the optical element 24 via the thermally conductive adhesive 26, that is, without involving elements other than the adhesive 26. Further, the heat of the conductor path 18 is transmitted from the thermally conductive potting material 28 to the housing 22 and is also transmitted to the optical element by heat convection through the air from the housing 22. Therefore, it is possible to avoid the formation of frost or dew on the optical element and to remove the already formed frost layer or dew.

[0033] It is conceivable that the strength and voltage of the current flowing through the conductor change depending on the desired heating power. Additionally or alternatively, in order to change the heating power, not only one conductor path 18 but also a plurality of conductor paths 18 may be provided on the circuit board 10 and operated individually or jointly. Also, it is conceivable that the conductor path 18 does not have the same cross-section over its entire length but the cross-section changes. For example, the conductor path 18 may have a continuously changing cross-section or may change only partially with respect to the cross-section. Generally speaking, the smaller the cross-section and the longer the conductor path, the higher the resistance, and vice versa. Therefore, the cross-section and length of the conductor path 18 can be calculated based on the desired heating power, the specified current intensity or voltage, and the specific thermal conductivity of the material selected for the conductor path 18.

[0034] The thermal barrier 13 functions as a kind of protective ring to prevent the heat of the conductor path 18 from being transmitted to the image sensor 16. By being made of a heat-insulating material, the thermal barrier 13 avoids heat transfer to the image sensor 16 and insulates the image sensor 16 from the conductor path 18. Alternatively, the thermal barrier 13 is made of a heat-conductive material and stores the heat of the conductor path 18 so that heat is not transmitted to the image sensor 16 or is not transmitted until a certain time. This heat-insulating effect is further improved by omitting and separating the circuit board layer 12 between the image sensor 16 and the conductor path 18. Omitting the circuit board layer 12 between the image sensor 16 and the conductor path 18 can also be one measure for heat insulation of the image sensor 16 (i.e., without providing the thermal barrier 13).

[0035] FIG. 4 is a perspective view of the circuit board 10. Here, the conductor path 18 is not only disposed on one circuit board layer 12 but also extends across a plurality of circuit board layers.

[0036] In the embodiment shown in FIG. 4, the surface heating portion 17 configured as the conductor path 18 is substantially formed from two conductor path portions 18a, 18b. The first conductor path portion 18a extends on the first circuit board layer 12a, while the second conductor path portion 18b extends on a second circuit board layer 12b substantially parallel to the first circuit board layer (not shown). Both conductor paths 18a, 18b are electrically connected to each other via a conductor path web 18c. Since the conductor path web 18c establishes conduction between the first conductor path portion 18a located on the first circuit board layer 12a and the second conductor path portion 18b located on a further circuit board layer 12b, the conductor path web 18c further extends in a spatial direction and the conductor path 18 is three-dimensionally configured at the position of the conductor path web 18c. However, in principle, the conductor path 18 formed by the conductor paths 18a, 18b mainly, and thus, passes through a wide portion configured two-dimensionally.

[0037] FIG. 4 shows that the two conductor path portions 18a and 18b overlap substantially exactly and are formed identically, respectively. Although the conductor path portions 18a and 18b are actually formed identically with respect to their planar extensions, they can be arranged offset laterally with respect to the longitudinal direction of the camera. Alternatively or additionally, it is also conceivable that the conductor path portions 18a and 18b are formed differently from each other with respect to their planar extensions. For example, the conductor path portion 18a located closer to the optical element 24 may have a larger extension with respect to its planar extension than the conductor path portion 18b located farther from the optical element 24 compared to the conductor path portion 18a. The cross-sections and materials of the conductor path portions 18a and 18b can also be different. Appropriate changes in the cross-section and / or material will be made in the conductor path web 18c, but can also occur at other positions of the conductor path portions 18a and 18b.

Explanation of Signs

[0038] 10: Circuit board 12, 12a, 12b: Circuit board layers 13: Thermal barrier 14: Electronic component 16: Image sensor 17: Surface heating part 18: Conductor path 18a, 18b: Conductor path portions 19: Power connector 20: Camera 22: Housing 24: Optical element 26: Adhesive 28: Potting material 30: Connector a - a': Central axis

Claims

1. A camera for a vehicle, comprising: a housing, at least one optical element, and a circuit board, wherein the at least one optical element is disposed within or on the housing, and the circuit board comprises at least one image sensor and a surface heating portion for heating the optical element.

2. The camera according to claim 1, wherein the surface heating portion is formed from at least one conductor path, and a conductor path portion of the conductor path is disposed on the circuit board to form a planar arrangement.

3. The camera according to claim 2, wherein the conductor path is disposed in a meandering shape.

4. The camera according to claim 2, wherein the conductor path is disposed at least partially around the image sensor.

5. The camera according to claim 2, wherein the conductor path is disposed on a surface of the circuit board facing the optical element.

6. The camera according to claim 2, wherein an outer boundary of the conductor path on the circuit board substantially coincides with an outer boundary of a surface of the optical element facing the conductor path.

7. The camera according to claim 2, wherein the conductor path is disposed on a specific conductor path layer of the circuit board.

8. The camera according to claim 7, wherein the conductor path has a substantially two-dimensional shape.

9. The camera according to claim 2, wherein the conductor path extends across a plurality of circuit board layers substantially parallel to each other.

10. The camera according to claim 9, wherein the conductor path has a three-dimensional shape.

11. The camera according to claim 5, wherein circuit board layers of the circuit board are separated in a region between the image sensor and the conductor path.

12. The camera according to claim 2, further comprising a thermal barrier, wherein the thermal barrier is provided between the image sensor and the conductor path.

13. The camera according to claim 12, wherein the thermal barrier is made of a heat conductive material and is configured to have a heat capacity.

14. The camera according to claim 2, comprising at least one second conductor path for selectively controlling in response to a heating power requirement.

15. The camera according to claim 1, further comprising a thermally conductive potting material The heat-conductive potting material is disposed between the circuit board, the housing, and the optical element, a camera. **Claim 16** In the camera according to claim 1, further comprising at least one temperature sensor, wherein the at least one temperature sensor is for detecting the temperature within the housing for adjustment of heating power and / or adjustment of heating time, a camera. **Claim 17** In the camera according to claim 2, the at least one conductor path is adapted to be used as a power supply line to the image sensor on the circuit board layer of the circuit board and / or to further components on the circuit board layer, a camera. **Claim 18** A vehicle, comprising the camera according to any one of claims 1 to 17, a vehicle.

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