JP2008010358A - Switch device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switch device having contacts connected by low-load operation, which does not erroneously operates even when receiving vibration from the outside and being used at high temperature. <P>SOLUTION: An thermoelectric conversion module 5 is formed of thermoelectric converters 7 connected in series. The thermoelectric converter 7 consists of a P-type semiconductor element 8 and an N-type semiconductor element 9. Touching a switch device 1 with a user's finger raises the temperature of a reference end portion 10 of the thermoelectric conversion element by user's body temperature, so that a voltage is generated at the output end portion 12 on the lower surface of the thermoelectric conversion element by Seebeck effect and the thermoelectric conversion module 5 outputs the voltage. Thus, a signal representing the touched position is output to a car navigation device from the switch device 1, so that the car navigation device operates according to the touched position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a switch device that is turned on by a low load operation.

In recent switch devices, there is an increasing need in the market for low-load switch devices, such as membrane switches, that can conduct between contacts by a low-load pressing operation.
A conventional membrane switch provides a predetermined gap with a spacer between a sheet-like movable electrode and a fixed electrode, and conducts between contacts with a low load by a user's pressing operation on the sheet-like movable electrode. (See Patent Document 1).
JP 2005-528740 Gazette

  However, since such a membrane switch is provided with a predetermined gap between the movable electrode and the fixed electrode formed on the sheet so that conduction between the contacts can be performed with a low load, the membrane switch is externally provided. When large vibrations are applied and the sheet-like movable electrode and fixed electrode vibrate, the movable contact may come into contact with the fixed contact. In such a case, the contacts may become conductive and malfunction may occur. was there.

In addition, when such a membrane switch is used in a high temperature situation, the sheet on which the movable electrode and the fixed electrode are formed may expand and bend due to heat. There was a risk of malfunction due to contact.
On the other hand, in a capacitive switch device that does not have the possibility of such a problem, especially when used in a car with many electronic devices, the electric field strength may change due to the influence of noise, resulting in malfunction. was there.

  The present invention has been made in view of the above circumstances, and its purpose is to use in a configuration in which contact is conducted with a low load operation, when external vibration is applied or when the temperature is high. Is to provide a switch device that does not cause malfunction.

  In order to achieve the above object, the switch device of the present invention connects the reference end portions of a pair of thermoelectric conversion elements having different potentials at the output end portion with respect to the reference end portion according to the temperature difference, using connection electrodes. When the voltage output from the thermoelectric conversion module is equal to or higher than a predetermined level, the thermoelectric conversion module is configured by connecting a plurality of thermoelectric conversion units in series. An output circuit that outputs a signal indicating that the module is touch-operated is provided, and the thermoelectric conversion module is configured such that the reference end portion of the thermoelectric conversion element can be touch-operated (Claim 1). .

The thermoelectric conversion element is preferably a semiconductor element (claim 2).
A plurality of the thermoelectric conversion modules are provided on a printed circuit board, and the output circuit is provided to output a signal indicating that a touch operation has been performed, and is configured as a membrane switch by covering the printed circuit board with a sheet member. (Claim 3).

  According to the means of claim 1, when the user touches the thermoelectric conversion module, the temperature of the reference end of the thermoelectric conversion element rises, so the temperature between the reference end of the thermoelectric conversion element and the output end Make a difference. As a result, a potential difference is generated at the output ends of the pair of thermoelectric conversion elements constituting the thermoelectric conversion unit. Although this potential difference is extremely small, the thermoelectric conversion module is configured by connecting the thermoelectric conversion units in series, so that the voltage from the thermoelectric conversion module can be increased to a detectable level. Therefore, since the output circuit can output a signal indicating that the thermoelectric conversion module has been touched, the external device can operate in accordance with the touch operation position with respect to the switch device. In this case, since the touch operation on the switch device is detected by a temperature change, the contact between the contacts is performed due to external vibration or thermal expansion of the electrode, and the switch device may malfunction. Can be prevented.

According to the means of claim 2, since the thermoelectric conversion element is a semiconductor element, a small thermoelectric conversion module can be manufactured. In addition, since a large voltage can be generated by a touch operation by using a semiconductor element having a large thermoelectric conversion effect, the touch operation by the user can be detected with high accuracy.
According to invention of Claim 3, since it can comprise as a membrane switch, it is suitable for manufacturing the switch apparatus for touch position detection.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 3 shows an embodiment in which the present invention is used as a switch device used for the operation of car navigation of an automobile. The switch device 1 is installed at a position where the driver can operate while driving the vehicle, and the operation position with respect to the switch device 1 is displayed as a cursor position on the display 3 of the car navigation 2. Yes.

  As shown in FIG. 3, the switch device 1 is configured by housing a printed circuit board 4 (see FIG. 1) in a case. A plurality of thermoelectric conversion modules 5 are mounted on the surface of the printed circuit board 4 in a matrix, and the thermoelectric conversion modules 5 are covered with a resin film 6 (corresponding to a sheet member) to constitute a membrane switch. . The user can perform a determination operation by gently tracing the surface of the switch device 1 and releasing his / her finger from the switch device 1 when the user comes to a position to be determined.

FIG. 1 is a longitudinal sectional view of the thermoelectric conversion module 5, and FIG. 2 is a perspective view of the thermoelectric conversion module 5. In these FIG.1 and FIG.2, the thermoelectric conversion module 5 is comprised by connecting the thermoelectric conversion part 7 linearly in series.
The thermoelectric conversion unit 7 is configured by connecting a rectangular parallelepiped P-type semiconductor element (corresponding to a thermoelectric conversion element) 8 and an N-type semiconductor element (corresponding to a thermoelectric conversion element) 9. In other words, the P-type semiconductor element 8 and the N-type semiconductor element 9 that form a pair are configured so that the reference end portions 10 that are the upper ends in the figure are connected by the upper connection electrode 11. The upper connection electrode 11 has a thin flat rectangular shape and is formed of a copper member having good thermal conductivity. The P-type semiconductor element 8 and the N-type semiconductor element 9 are configured by connecting output end portions 12 as lower ends in the figure with lower connection electrodes 13.

  The P-type semiconductor element 8 and the N-type semiconductor element 9 generate a voltage between both ends by the Seebeck effect according to the temperature difference between the reference end portion 10 and the output end portion 12. In this case, when the temperature of the reference end portion 10 is higher than that of the output end portion 12, the voltage of the output end portion 12 is higher than that of the reference end portion 10 in the P-type semiconductor element 8, and the output end in the N-type semiconductor element 9. The voltage of the part 12 is lower than that of the reference end part 10. Accordingly, when focusing on one thermoelectric conversion unit 7, the voltage at the output end 12 of the P-type semiconductor element 8 is less than that of the N-type semiconductor element 9 under the condition that the temperature of the reference end 10 is higher than that of the output end 12. It becomes higher than the voltage of the output end 12.

In this way, the plurality of thermoelectric conversion units 7 having voltage generation characteristics according to the temperature difference are connected in series on the straight line by the lower connection electrodes 13. This is because the output voltage from one thermoelectric conversion element is as small as several μV, so that a plurality of thermoelectric conversion elements are connected in series so that the output voltage can be increased and detected. The lower connection electrode 13 of the N-type semiconductor element 9 located at the end of the thermoelectric conversion module 5 is connected to the 0V line, and the lower connection electrode 13 located at the opposite end is referenced to 0V. Will be output.
The vertical direction used in the description of the present embodiment refers to the surface on which the user performs a touch operation by touching the finger when using the switch device 1 and the surface in the opposite direction as the bottom. is there.

As shown in FIG. 1, the upper surface of the thermoelectric conversion module 5 is covered with a resin film 6.
The lower connection electrodes 13 of the thermoelectric conversion part 7 located at both ends of the thermoelectric conversion module 5 extend laterally, and the extension parts are connected to a predetermined conductive pattern of the printed circuit board 4 by wire bonding 14. And connected to the output circuit 15 through the conductive pattern.

The wire bond 14 is mechanically protected by protection means (not shown) so as not to be damaged when the user touches the resin film 6.
FIG. 4 is a block diagram schematically showing the electrical configuration of the switch device 1. In FIG. 4, the output of the thermoelectric conversion module 5 is input to the output circuit 15. The output circuit 15 detects whether the input voltage from each thermoelectric conversion module 5 is equal to or higher than a predetermined level. If the input voltage is higher than the predetermined level, a signal indicating the position of the thermoelectric conversion module 5 is sent to the car navigation 2. Output. In this case, when the input voltages from the plurality of thermoelectric conversion modules 5 simultaneously exceed a predetermined level, signals indicating their positions are output.

  The car navigation 2 displays a button corresponding to the operation that can be operated at that time on the display 3, and when the cursor displayed on the display 3 based on the signal from the switch device 1 is positioned on the button. The button is selected and displayed (for example, inverted display or blinking display). Further, when it is detected that the touch operation (low load operation) on the switch device 1 is released in such a button display state, it is determined that the selected button is finally selected and the button is selected. A corresponding predetermined operation is executed.

Next, the operation of the above configuration will be described. When the car navigation 2 is operated, a button corresponding to an operation that can be operated at that time is displayed on the display 3.
The driver of the vehicle performs a touch operation with a finger on the surface of the switch device 1 as if tracing the surface of the switch device 1. Then, since the temperature of the upper connection electrode 11 of the thermoelectric conversion module 5 located at the part where the touch operation is performed with the finger rises in a short time due to the heat of the body temperature conducted from the finger, the upper connection electrode 11 (reference end) A temperature difference is generated between the portion 10) and the lower connection electrode 13 (output electrode). Thus, when a temperature difference arises between the upper connection electrode 11 and the lower connection electrode 13, a voltage is generated from the thermoelectric conversion module 5 by the Seebeck effect.

  The output circuit 15 outputs a signal indicating the position of the thermoelectric conversion module 5 to the car navigation 2 when the voltage from the thermoelectric conversion module 5 exceeds a predetermined level. In this case, when the voltages from the plurality of thermoelectric conversion modules 5 simultaneously exceed a predetermined level according to the touch operation by the user, a signal indicating the positions of the thermoelectric conversion modules 5 is output to the car navigation 2.

  When the signal input from the switch device 1 indicates one position, the car navigation 2 moves the cursor displayed on the display 3 to that position. When a plurality of positions are indicated, the cursor is moved to the center position thereof. Therefore, when the driver moves the operation position with respect to the switch device 1, the cursor position displayed on the display 3 is moved accordingly. At this time, when the cursor is positioned on the button displayed on the display 3, the button is selected to indicate that the button is selected.

  When a desired button displayed on the display 3 is selected and displayed by a touch operation on the switch device 1, the driver releases the touch operation on the switch device 1. Thereby, since the thermoelectric conversion module 5 at that position is finally turned off at the position where the finger is released from the switch device 1, the car navigation 2 is determined to have been performed at the position of the thermoelectric conversion module 5 that was turned off last. to decide. In this case, as in the case where the thermoelectric conversion module 5 is turned on, when a plurality of switch elements are turned off at the same time, it is determined that the determination operation has been performed at the center position.

When the determination operation is performed in a state where the buttons are selected and displayed as described above, the car navigation 2 performs an operation according to the button selected and displayed at that time.
By the way, since the switch device 1 of the present embodiment is mounted on a vehicle, a large vibration is applied to the switch device 1 from the outside when the vehicle is running. In the conventional membrane switch, the contacts may be brought into contact with each other due to vibration.

Moreover, in the season when the temperature rises such as summer, the temperature inside the vehicle becomes high particularly when the vehicle is stopped, and the switch device 1 may become high temperature. In the conventional membrane switch, the sheet sandwiching the movable electrode and the fixed electrode may expand due to heat and the contacts may come into contact with each other, which may cause malfunction.
On the other hand, in a capacitive switch device that does not have the possibility of such a problem, especially when used in a car with many electronic devices, the electric field strength may change due to the influence of noise, resulting in malfunction. was there.

  However, according to the present embodiment, since the touch operation is detected based on the voltage generated by the touch operation on the thermoelectric conversion module 5, a mechanical contact such as a movable contact or a fixed contact is provided like a membrane switch. The switch device 1 can be configured using an electrical means called a thermoelectric conversion module 5 that detects body temperature conducted from the user's finger. Therefore, it is possible to realize the switch device 1 that is not affected by external vibrations or heat, and that is not affected by noise of electronic devices provided in the surroundings.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following modifications or expansions are possible.
The semiconductor element may be formed of a metal exhibiting the Seebeck effect, such as a copper member or a nickel member.

The pair of thermoelectric conversion elements constituting the thermoelectric conversion unit 7 may have different shapes and sizes.
The thermoelectric conversion module 5 is connected to the conductive pattern of the printed circuit board 4 by the wire bond 14. In short, the thermoelectric conversion module 5 only needs to be connected to the conductive pattern of the printed circuit board 4. You may make it connect with.

As the thermoelectric conversion module 5, a plurality of semiconductor elements are connected in series on a straight line, but may be meandering or spiral as long as they are connected in series.
The voltage from the thermoelectric conversion module 5 may be amplified by an amplifier circuit.

The longitudinal cross-sectional view of the thermoelectric conversion module which shows one Example of this invention Perspective view of thermoelectric conversion module Perspective view of switch device Block diagram schematically showing the electrical configuration of the switch device

Explanation of symbols

  In the drawings, 1 is a switch device, 4 is a printed circuit board, 5 is a thermoelectric conversion module, 6 is a resin film (sheet member), 8 is a P-type semiconductor element (thermoelectric conversion element), and 9 is an N-type semiconductor element (thermoelectric conversion element). ) 10 is a reference end, 12 is an output end, and 15 is an output circuit.

Claims (3)

A thermoelectric conversion unit is configured by connecting the reference end portions of a pair of thermoelectric conversion elements having different potentials at the output end portion with respect to the reference end portion in accordance with a temperature difference by connection electrodes, and a plurality of thermoelectric conversion portions are provided. A thermoelectric conversion module configured by connecting in series;
An output circuit that outputs a signal indicating that the thermoelectric conversion module is touch-operated when the voltage output from the thermoelectric conversion module exceeds a predetermined level;
The thermoelectric conversion module is configured so that the reference end of the thermoelectric conversion element can be touch-operated.   The switch device according to claim 1, wherein the thermoelectric conversion element is a semiconductor element. A plurality of the thermoelectric conversion modules are provided on the printed circuit board,
The output circuit is provided to output a signal indicating that a touch operation has been performed,
3. The switch device according to claim 1, wherein the switch device is configured as a membrane switch by covering the printed board with a sheet member.

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