Temperature sensor device for a vehicle windshield

Abstract

The invention relates to a temperature sensor device (10, 20) for sensing the temperature of a vehicle windscreen (5), comprising a single printed circuit board (1, 21) comprising a circuit (3, 23), in particular a measurement and control circuit (3, 23), a temperature sensor (4, 24), in particular a thermistor, mounted on the printed circuit board (1, 21), and a thermally conductive pad (6, 26) attached to the temperature sensor (4, 24), the thermally conductive pad (6, 26) being arranged in direct thermal and mechanical contact with the windscreen (5).

Description

Technical Field

[0001] This invention relates to a temperature sensor device for sensing the temperature of a vehicle windshield, and more particularly, a temperature sensor device for sensing the temperature of a car windshield. Background Technology

[0002] Temperature sensors, humidity sensors, optical sensors, or combinations thereof are known to be used in windshield sensing devices installed in vehicles to automatically control the heating, ventilation, air conditioning, and operation of windshield wipers. As an example, windshield temperature sensing devices are commonly used in anti-fogging situations.

[0003] To allow for accurate and reliable monitoring of the temperature and / or humidity of the vehicle's windshield, the sensors of the sensing device must reliably maintain continuous contact with the windshield surface throughout the vehicle's entire lifespan. Therefore, the sensors and their connection to the windshield must be able to withstand mechanical shocks and vibrations throughout their lifespan. Consequently, the sensors need to be securely attached to the windshield.

[0004] As is known in the art, sensor devices include printed circuit boards (PCBs). For example, a thermistor is attached to a flexible polyimide film. One end of the polyimide film is connected to the PCB, and the other end of the thermistor, which is attached thereto, is attached to a windshield surface 20. The end with the thermistor can be pressed against the windshield surface by foam elements made of thermal foam arranged on either side of the thermistor. However, the foam used to fix the polyimide film and the thermistor to the windshield is subject to aging, degradation, and / or mechanical stress. Furthermore, the soldering of the thermistor to the polyimide film, the soldering of the sensing device to the PCB, and the soldering of the connector pins to the PCB represent a rather complex and expensive manufacturing process.

[0005] In another method, the windshield temperature is measured using a thermistor attached to a PCB in contact with the windshield and connected via two spring elements to another PCB that processes the measurement data. These spring elements also attempt to maintain permanent contact between the PCB with the thermistor and the windshield surface. Again, the entire manufacturing process is quite time-consuming and expensive, resulting in a rather complex structure that is easily detachable from the windshield.

[0006] According to alternative methods, the thermistors are placed on a flexible PCB. Again, the entire manufacturing process is quite time-consuming and expensive.

[0007] In view of the above, the object of the present invention is to provide a temperature sensor device for a vehicle windshield that can be easily manufactured at low cost while still allowing reliable and permanent sensing operation. Summary of the Invention

[0008] The present invention addresses the above-mentioned objective by providing a temperature sensor device for sensing the temperature of a vehicle windshield. The temperature sensor device includes: a single printed circuit board (PCB) including circuitry; a temperature sensor (temperature sensing device) mounted on the PCB; and a thermal pad attached to the temperature sensor and arranged to be in direct thermal and mechanical contact with the windshield (inner surface).

[0009] The circuit may include measurement and control circuitry for processing data sensed by the temperature sensor and controlling the temperature sensor. The temperature sensor may be a thermistor. The thermal pad may be composed of or comprise metallic materials, such as precious metals like gold or copper. The temperature sensor may, for example, be soldered to a printed circuit board. The printed circuit board may be a non-flexible (rigid) printed circuit board. Another sensor, such as a humidity sensor, may be additionally mounted on the printed circuit board.

[0010] The configuration thus defined can be manufactured relatively simply and cost-effectively using only a single PCB on which the temperature sensor is mounted. In particular, an easily achievable thermal contact is obtained by attaching a thermal pad to the temperature sensor and arranging it to directly contact the inner surface of the windshield, allowing for a long-term reliable temperature measurement process.

[0011] According to an embodiment, the printed circuit board includes a tab portion (extension), and a temperature sensor is mounted on the tab portion. This facilitates easier positioning of the temperature sensor via a thermal pad contacting the windshield. The thermal pad can also be attached to the tab portion of the printed circuit board to promote reliable and permanent thermal contact between the thermal pad and the windshield. Specifically, the thermal pad can be attached to the edge of the tab portion of the printed circuit board.

[0012] The printed circuit board includes conductive and thermally conductive wires, particularly copper wires, which can be arranged to receive some heat flow from the windshield, and the temperature sensor can be arranged to have thermal contact with at least some of the wires. When the temperature sensor device is attached to the vehicle windshield, the wires can provide thermal conduction of heat radiated from the windshield toward the temperature sensor, thereby significantly improving the accuracy of temperature measurement.

[0013] Furthermore, the printed circuit board may include openings disposed between at least some portions of the circuit and the temperature sensor. Such openings also improve the accuracy of temperature measurements because the impact of heat generated by the electronic components of the circuit on the temperature sensing performed by the temperature sensor can be significantly reduced.

[0014] According to one embodiment described above, the temperature sensor device may further include an attachment device configured to attach the temperature sensor device to a windshield, wherein the attachment device includes at least one portion arranged and configured to conduct heat generated by the circuit away from the temperature sensor, so as to further improve the accuracy of temperature measurement by the temperature sensor device.

[0015] The attachment device may include or consist of a clamping member, particularly a clamping member made of or comprising a metallic material, wherein at least one portion arranged and configured to conduct heat generated by the circuit away from the temperature sensor is part of the clamping member.

[0016] In addition, a defogging control device or a wiper operation control device for a motor vehicle including a windshield is provided, the defogging control device or wiper control device including a humidity sensor device for sensing the humidity of the windshield and a temperature sensor device according to one embodiment described above.

[0017] In addition, a method for attaching a temperature sensor device to a vehicle windshield is provided, the method comprising the following steps:

[0018] Provide bracket devices for installation on rearview mirrors or windshields in vehicles;

[0019] A temperature sensor device according to one embodiment of the above is provided, wherein the printed circuit board of the temperature sensor device includes thermally conductive and electrically conductive lines; and

[0020] The temperature sensor device thus provided is fastened to the bracket device so that the thermal pad is in direct thermal and mechanical contact with the windshield on the inner surface of the windshield facing the vehicle compartment.

[0021] In addition, the temperature sensor device can be secured to the bracket in such a way that the thermally conductive and conductive lines of the printed circuit board are in thermal contact with the windshield.

[0022] Additional features and advantages of the invention will be described with reference to the accompanying drawings. Preferred embodiments of the invention are illustrated in the description with reference to the drawings. It should be understood that these embodiments do not represent the full scope of the invention. Attached Figure Description

[0023] The invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0024] Figure 1 An exemplary embodiment of the temperature sensor device according to the present invention is shown, along with a cross-sectional view of a portion of the temperature sensor device.

[0025] Figure 2 The following illustration shows aspects of the temperature sensor device according to the invention related to thermal control in the context of exemplary embodiments. Detailed Implementation

[0026] This invention provides a temperature sensor device for sensing the temperature of a vehicle windshield, wherein the temperature sensor device includes a single inflexible PCB and a temperature sensor mounted on the PCB. The inflexible PCB (i.e., a rigid PCB) cannot be significantly bent or rolled up without damage. The bending radius of the PCB used herein can be particularly less than 1 mm. The temperature sensor device includes a temperature sensor that is in thermal contact with the windshield via a thermally conductive pad.

[0027] Figure 1 An exemplary embodiment of the temperature sensor device 10 according to the present invention is shown, along with a cross-sectional view of the temperature sensor device 10 in the direction indicated by the arrow. A PCB 1 is encapsulated in a housing 2. Several circuits 3 are formed on the PCB 1. The circuits 3 include circuit elements for data processing and sensor control.

[0028] The PCB includes a tab portion 1a. A temperature sensor 4 is attached to the tab portion 1a of the PCB. Thus, the temperature sensor 4 is directly mounted to the PCB 1. For example, the temperature sensor 4 is soldered to the tab portion 1a. In fact, the temperature sensor 4 may be soldered to the tab portion 1a of the PCB 1 during the soldering of all or some other electronic components of the circuit 3 (e.g., in some reflow processes) to the PCB 1.

[0029] According to an embodiment, the temperature sensor 4 is a thermistor. The thermistor can be a negative temperature coefficient (NTC) thermistor, characterized by an exponential decrease in resistance with increasing sensing temperature. The NTC thermistor can be made based on polycrystalline oxide ceramic, particularly exhibiting a crystalline structure that is essentially a spinel structure resulting from the sintering process.

[0030] In order to sense the temperature of the vehicle's windshield 5, reliable thermal contact with the windshield 5 is required. For example... Figure 1 As shown, thermal contact is provided via a thermal pad 6 connected to the temperature sensor 4. The thermal pad 6 may be made of or comprise precious metals, such as gold or copper or some alloys thereof. It should be noted that the temperature sensor 4 does not have direct contact with the windshield, but rather the contact is made via the thermal pad 6. Therefore, degradation of the temperature sensor 4 during its service life can be reduced. The housing 2 includes an extension 2a corresponding to the thermal pad 6, which may also contact the windshield 5.

[0031] To attach the temperature sensor device 10 to the windshield 5, an attachment device 7 is provided. The attachment device 7 for the temperature sensor device 10 may include a clamping member, such as a metal clamping member, configured to clamp onto a bracket member, which may be positioned, for example, on the windshield or on a rearview mirror mounted in a vehicle.

[0032] When the clamping component 27 is fastened to the support component, reliable and permanent mechanical and thermal contact is achieved between the windshield 5 and the temperature sensor device 10 (and - via the thermal pad 6 - the temperature sensor 4 of the temperature sensor device 10). The temperature sensor device 10, for example, enables low-cost defogging control and / or wiper control within the vehicle cabin.

[0033] exist Figure 2 Another embodiment of the temperature sensor device 20 of the present invention is shown. The temperature sensor device 20 and... Figure 1 The devices shown are very similar. The temperature sensor device 20 includes a single rigid PCB 21, which is encapsulated in a housing 22. Some circuitry 23 is formed on the PCB 21. The circuitry 23 includes circuitry elements for data processing and sensor control.

[0034] A temperature sensor 24, such as an NTC thermistor, is attached to a tab portion 21a of the PCB 21. Thus, the temperature sensor 24 is directly mounted to the PCB 21. For example, the temperature sensor 24 is soldered to the tab portion 21a of the PCB 21. The temperature sensor 24 is connected to a thermal pad 26, which may be made of or include precious metals, such as gold. The thermal pad 26 provides thermal contact with the windshield, the temperature of which needs to be sensed by the temperature sensor 24.

[0035] The clamping member 27 is used for attaching the temperature sensor device 20 to the vehicle windshield. The clamping member includes a clamping tab 27a, which is fastened to the housing and can also be fastened to the PCB 21. In particular, the clamping tab 27a is in thermal contact with the circuitry 23 formed on the PCB 21.

[0036] The heat flow generated by the electronic components of PCB21 is due to Figure 2 The arrows in the diagram indicate that the heat generated by the electronic components of the circuit 23 on PCB 21 should not affect the measurement of the windshield temperature using the temperature sensor 24. Therefore, the clamping tabs 27a of the clamping member 27 are made of, for example, a metallic material that allows heat to be conducted away from the temperature sensor 24.

[0037] In addition, thermal barriers can be provided to block the heat flow toward the temperature sensor 24. Figure 2 In the illustrated embodiment, such a barrier includes an opening 29 formed in the PCB 21, which allows heat generated by the electronic components of the circuit 23 of the PCB 21 to dissipate.

[0038] All the foregoing embodiments are not intended to be limiting but are used as examples to illustrate the features and advantages of the invention. It should be understood that some or all of the foregoing features can also be combined in different ways.

[0039] Appendix Number

[0040] 1,21 PCB

[0041] 1a, 21a lamina portion

[0042] 2.22 Shell

[0043] 2a Extension

[0044] 3.23 circuit

[0045] 4.24 Temperature Sensor

[0046] 5. Windshield

[0047] 6.26 Thermal pad

[0048] 7. Attachment Devices

[0049] 10, 20 Temperature sensor device

[0050] 27. Fixture components

[0051] 27a Clamping tab

[0052] 29 Opening

Claims

1. A temperature sensor device (10, 20) for sensing the temperature of a vehicle windshield (5), comprising: A single printed circuit board (1, 21), the printed circuit board (1, 21) including circuitry (3, 23); Temperature sensors (4, 24) are mounted on printed circuit boards (1, 21); and A thermal pad (6, 26) is attached to a temperature sensor (4, 24) and is arranged to be in direct thermal and mechanical contact with the windshield (5). The printed circuit board (1, 21) includes tab portions (1a, 21a), and a temperature sensor (4, 24) is mounted to the tab portion (1a, 21a), and a thermal pad (6, 26) is attached to the tab portion (1a, 21a) of the printed circuit board (1, 21). The temperature sensor device further includes an attachment device (7) configured to attach the temperature sensor device (10, 20) to the windshield (5). The attachment device (7) includes or is composed of a clamping member (27), a portion of which is arranged and configured to conduct heat emitted by the circuit (3, 23) away from the temperature sensor (4, 24).

2. The temperature sensor device (10, 20) according to claim 1, wherein, The circuit (3, 23) is a measurement and control circuit (3, 23).

3. The temperature sensor device (10, 20) according to claim 1, wherein, The temperature sensor (4, 24) is a thermistor.

4. The temperature sensor device (10, 20) according to claim 1, wherein, The thermal pads (6, 26) are attached to the edges of the tab portions (1a, 21a).

5. The temperature sensor device (10, 20) according to claim 1, wherein, The printed circuit board (1, 21) includes conductive and thermally conductive wires arranged to receive some heat flow from the windshield (5), and wherein a temperature sensor (4, 24) is arranged to be in thermal contact with at least some of the conductive and thermally conductive wires.

6. The temperature sensor device (10, 20) according to claim 5, wherein, The conductive and heat-conducting wires are copper wires.

7. The temperature sensor device (10, 20) according to claim 1, wherein, The printed circuit board (1, 21) includes an opening (29) arranged between at least some portions of the circuit (3, 23) and the temperature sensor (4, 24).

8. The temperature sensor device (10, 20) according to any one of claims 1-7, wherein, Temperature sensors (4, 24) are soldered to printed circuit boards (1, 21).

9. The temperature sensor device (10, 20) according to any one of claims 1-7, wherein, The printed circuit board (1, 21) is a non-flexible printed circuit board (1, 21).

10. The temperature sensor device (10, 20) according to claim 1, wherein, The clamp component (27) is made of or includes a metallic material.

11. A defogging control device or wiper operation control device for a motor vehicle including a windshield (5), said defogging control device or wiper operation control device comprising: A humidity sensor device configured to sense the humidity of the windshield (5); and Temperature sensor device (10, 20) according to any one of the preceding claims.

12. A method for attaching a temperature sensor device (10, 20) to a vehicle windshield (5), comprising the steps of: Provide bracket devices at the rearview mirror or windshield (5) installed in the vehicle; Provide a temperature sensor device (10, 20) according to claim 1; and The temperature sensor device (10, 20) according to claim 1 is fastened to the bracket device such that the thermal pad (6, 26) is in thermal and mechanical direct contact with the windshield (5) on the inner surface of the windshield (5) facing the vehicle compartment.

13. The method according to claim 12, wherein, The printed circuit board (1, 21) of the temperature sensor device (10, 20) includes a plurality of conductive and thermally conductive wires, wherein the temperature sensor device (10, 20) is fastened to a support device such that at least some of the plurality of conductive and thermally conductive wires are in thermal contact with the windshield (5).

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