JP2013131317A - Electrostatic capacitance type touch switch and electronic device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic capacitance type touch switch that prevents adhesion of water or the like from being erroneously detected as a touch by a finger using a simple construction.SOLUTION: An electrostatic capacitance type touch switch includes: a front panel 150 formed using a plate or film-like dielectric; a switch region 161 provided for a front surface 150A of the front panel 150 to have a predetermined area; an electrode pad 321 provided to closely contact a back surface 150B of the front panel 150 at a position and in a shape corresponding to the switch region; and a detection circuit 400 that detects, based on a change of a capacitance, whether a finger touches the switch region, wherein the electrode pad 321 is divided into at least two division areas (321A, 321B) with respect to the single switch region 161 and the detection circuit determines, for each division area of the electrode pad, whether a conductive substance touches the switch region and, when determining that the conductive substance touches the switch region simultaneously for every division area of the electrode pad in a predetermined determination time period, determines that a finger touches the switch region.

Description

  The present invention relates to a switch using a capacitive contact sensor, and in particular, when a highly conductive substance such as water (hereinafter referred to as “conductive substance”) adheres to the switch, it is determined by a user's fingertip. The present invention relates to a capacitance-type contact switch having a function of preventing erroneous determination as being a contact, and an electronic device using the same.

  Conventionally, capacitive contact switches have been widely used. The capacitive contact switch includes a dielectric and an electrode pad attached to the back surface of the dielectric. When the fingertip is brought close to the surface of the dielectric, the fingertip and the electrode are sandwiched between the dielectrics. A change in capacitance generated between the pads is detected by a detection circuit, and it is determined whether a finger touches or is away from the switch.

  However, the capacitance contact switch changes the capacitance even if a conductive material such as water adheres to the switch portion, that is, the switch area on the dielectric surface. There is a possibility that the contact is erroneously determined.

  Various methods for preventing such false detection have been developed so far. For example, the following Patent Document 1 (Japanese Patent Laid-Open No. 2009-250857) makes it difficult for moisture and oil to adhere to the sensor surface by applying a water-repellent (oil-repellent) process to the sensor surface. A “capacitance sensor” is disclosed in which water (oil repellent) has been processed to disperse moisture and oil and easily flow down. This structure can prevent erroneous detection due to water droplets.

  Furthermore, the following Patent Document 2 (Japanese Patent Application Laid-Open No. 2008-141329) detects a switch electrode necessary for an on / off switch operation and a case where a conductive substance such as water is attached around the switch electrode. And an electrode film printed with a pattern on which the electrode is arranged is attached to a dielectric, and by comparing the change in capacitance with a predetermined threshold, it is an operation with a finger or water, etc. A “capacitance touch switch device” for determining whether or not a conductive material is attached is disclosed.

  Further, the following Patent Document 3 (Japanese Unexamined Patent Application Publication No. 2009-111996) discloses a switch electrode formed as a circular pattern having a diameter slightly larger than the size of the index finger, and a substantially annular shape disposed so as to surround the periphery of the switch electrode. A “contact sensor” including a dummy electrode is disclosed.

JP 2009-250857 A JP 2008-141329 A JP 2009-111996 A

The capacitance-type contact switches disclosed in Patent Documents 1 to 3 above all have a function of preventing contact with a conductive material such as water from being erroneously detected as contact with a finger. Thus, under an environment where there is a possibility of being directly exposed to water droplets, it is difficult to prevent erroneous detection due to water droplets or the like only by subjecting the sensor surface to water repellent processing as in Patent Document 1.

  Further, in the capacitance type contact switches disclosed in Patent Documents 2 and 3, a water detection electrode or a dummy electrode must be provided around the original electrode, and the switch is configured. There is also a problem that it leads to an increase in elements (parts) to be processed and an increase in manufacturing man-hours.

  Therefore, the object of the present invention is to make a simple configuration without increasing the number of elements (parts) constituting the switch, and even if a conductive substance such as water is attached, it is erroneously detected as contact with a finger. It is an object of the present invention to provide a capacitive contact switch that does not.

  The capacitive contact switch of the present invention includes a plate or film-like dielectric having a first surface and a second surface, a switch area having a predetermined area provided on the first surface of the dielectric, An electrode pad that is in close contact with the second surface of the dielectric in a position and shape corresponding to the switch region, and a detection circuit that detects whether a finger is in contact with the switch region based on a change in capacitance; The electrode pad is divided into at least two with respect to the one switch region, and the detection circuit corresponds to the at least two divided electrode pads. It is determined whether or not a conductive material has contacted each of the switch regions, and it is determined that the conductive material has simultaneously contacted the switch regions corresponding to all the electrode pads within a predetermined determination time. And judging the a finger is in contact with the switch region when.

  Moreover, the electronic device of the present invention is an electronic device using the above-described capacitive contact switch, wherein the first and second surfaces of the dielectric are horizontal surfaces. Embedded in the electronic device so as to form a predetermined angle with respect to the electrode, the electrode pad being in the second surface and at least along a line perpendicular to a tangent between the second surface and a horizontal surface It is divided into two parts.

  Furthermore, in one aspect of the electronic apparatus of the present invention, the electronic apparatus is a bathroom television set.

  According to the capacitive contact switch of the present invention, the following excellent effects are exhibited. That is, a switch region is provided on the first surface of the dielectric, and an electrode pad divided into at least two portions is brought into close contact with the second surface at a position corresponding to one switch region. Then, when the conductive material contacts the switch region, it is determined whether or not the contact of the conductive material is detected in each of the electrode pads, and the contact of the conductive material is detected in all the electrode pads within a predetermined determination time. In this case, it is determined that the finger touches the switch area. This prevents false detection by a simple configuration without increasing the number of components (parts) of the switch by providing an electrode for preventing false detection in a part other than the switch area, and increasing the number of manufacturing steps. Will be able to.

According to the electronic device of the present invention, the above-described capacitance switch is incorporated in the electronic device in a state where the first surface and the second surface of the dielectric form a predetermined angle with respect to the horizontal plane. The electrode pad is at least divided into two along a line in the second plane and perpendicular to the tangent line between the second plane and the horizontal plane. With such a structure, a conductive material such as water adhering to the first surface of the dielectric moves downward due to gravity, but at this time, the water or the like moves along a perpendicular to a tangent to the horizontal plane. Therefore, since the conductive material such as water does not move in the horizontal direction, the electrode pad is divided into two or more along this perpendicular, and the contact of the conductive material is made to all the electrode pads within a predetermined determination time. If it is determined that the contact is a finger contact when detected, it is possible to distinguish between a contact by a conductive substance such as water and a contact by a finger and prevent erroneous detection.

  Furthermore, according to one aspect of the electronic apparatus of the present invention, the above-described electronic apparatus is a bathroom television apparatus. According to the present invention, in a television set used in an environment where water drops or the like are frequently bathed in a bathroom or the like, even if a conductive substance such as water adheres to the capacitive contact switch, it can be touched with fingers. It is possible to prevent erroneous detection.

It is the external appearance perspective view which looked at the television apparatus for bathrooms of the Example from diagonally forward. It is the disassembled perspective view which looked at the television apparatus for bathrooms of FIG. 1 from diagonally forward in the state which removed the front panel. It is a disassembled perspective view which shows the state which removed the part of the electrostatic capacitance type contact switch while removing the 2nd housing from the television apparatus for bathrooms of FIG. It is the enlarged view which extracted only the part of the electrostatic capacitance type contact switch in the television apparatus for bathrooms of an Example. It is a figure which shows the electrostatic capacitance type contact switch of the television apparatus for bathrooms of an Example, FIG.5 (a) is the elements on larger scale when conductive substances, such as water, adhered to the front panel, FIG.5 (b) is FIG. The partial enlarged view when a finger contacts the front panel is shown.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described in detail below with reference to the drawings together with embodiments. However, the embodiments described below are described by exemplifying a capacitive television switch for embodying the technical idea of the present invention and a bathroom television apparatus as an electronic device using the same. The invention is not intended to specify the bathroom television apparatus, and is equally applicable to other capacitive contact switches and electronic devices using the same without departing from the technical idea shown in the claims. It is possible.

  With reference to FIGS. 1-5, the television apparatus for bathrooms of a present Example is demonstrated. 1 is an external perspective view of the bathroom television set according to the embodiment as seen from diagonally forward. FIG. 2 is a perspective view of the bathroom television set of FIG. 1 as seen from diagonally forward with the front panel removed. FIG. 3 is an exploded perspective view, FIG. 3 is an exploded perspective view showing a state in which the second housing is removed and the capacitive contact switch is disassembled, and FIG. It is the enlarged view which extracted only the part of the electrostatic capacitance type contact switch in the television apparatus for bathrooms of an Example, and is a figure which shows the electrostatic capacity type contact switch of the television apparatus for bathrooms of an Example, Comprising: FIG. ) Is a partially enlarged view when a conductive material such as water adheres to the front panel, and FIG. 5B is a partially enlarged view when a finger contacts the front panel.

  The illustrated bathroom television apparatus 10 includes a front housing 100 and a rear housing 200, a liquid crystal unit 500 installed in these housings, and a control circuit (not shown) for controlling the operation of the bathroom television apparatus 10. A switch substrate 300 and a control substrate 400 for performing control of the capacitive contact switch are provided.

  The front housing 100 includes an upper plate 110, a lower plate 120, a left side plate 130, a right side plate 140, and a rectangular front panel 150, and a frame 170 is formed in an internal space formed by these five surfaces. It is inserted. The frame 170 may be formed integrally with the upper plate 110, the lower plate 120, the left side plate 130, and the right side plate 140, and only the front panel 150 may be detachably fixed to the front surface of the frame 170.

  The frame 170 is a rectangular parallelepiped member having a predetermined width, height, and depth. A liquid crystal unit opening 171 is formed in an upper portion of the frame 170, and the liquid crystal unit 500 is incorporated therein. In addition, speaker openings 172A and 172B are formed on the left and right sides of the frame 170, and a speaker (not shown) is attached. Further, a substrate mounting portion 173 is formed between the speaker openings 172A and 172B, and the switch substrate 300 is mounted thereon. A flexible printed circuit board through hole (hereinafter referred to as an FPC through hole) 174 is provided at the right end of the substrate mounting portion 173. Further, a support portion (not shown) is provided on the back side of the substrate placement portion 173 of the frame 170, and the control substrate 400 is attached. Further, the substrate mounting portion 173 is provided with LED through-holes 175 described later at positions corresponding to switch regions 161 to 165 and LED openings 331 to 336 of the switch substrate 300 described later. Further, a sensor through hole 176 is formed on the left side of the substrate mounting portion 173 of the frame 170.

  In the present specification, the bathroom TV apparatus 10 is used with the surface 150A of the front panel 150 placed at a predetermined angle with respect to a horizontal plane. Preferably, the front panel 150 is used in a vertical posture with respect to the horizontal plane. Therefore, in this specification, the “width direction” refers to a direction (normal direction of the left and right side plates) from the left side plate 130 toward the right side plate 140 when applied to the first housing 100. The “height direction” refers to a direction (vertical direction with respect to the horizontal plane) from the lower plate 120 toward the upper plate 110, and the “depth direction” refers to the normal direction of the front panel 150.

  The second housing 200 includes an upper plate 210, a lower plate 220, a left side plate (not shown), a right side plate 240, and a back plate 250, and receives a liquid crystal unit 500, a control circuit (not shown), and the like inside. Configure the space. At the time of assembly, the first housing 100 and the second housing 200 are combined with each other. The first housing 100 has a second plate on the inner side of the upper plate 110, the lower plate 120, the left plate 130, and the right plate 140, respectively. An upper plate 210, a lower plate 220, a left side plate, and a right side plate 240 of the housing 200 are inserted with a packing such as a seal ring interposed therebetween, and the inside is sealed.

  The front panel 150 is fixed to the front surface of the frame 170. The front panel 150 is a plate-like member formed of a dielectric material such as glass or acrylic resin. A display region 151 is provided on the front panel 150 at a position corresponding to the position of the liquid crystal unit opening 171 of the frame 170. The display area 151 is formed by pasting an opaque film such as a black film over the entire back surface 150B of the front panel 150 and making the display area 151 a transparent area where the black film is not pasted. . Therefore, the image of the liquid crystal unit 500 located behind the display area 151 can be seen through the transparent display area 151.

  A plurality of small openings are provided on both the left and right sides of the lower portion of the front panel 150 to constitute speaker regions 152A and 152B. The speaker region 152 is formed at a position corresponding to the positions of the speaker openings 172A and 172B provided in the frame 170, and the sound of a speaker (not shown) attached to the speaker openings 172A and 172B. Is pronounced externally.

An operation unit 160 is provided between the left and right speaker regions 152A and 152B. The operation unit 160 includes volume adjustment switch areas 161 and 162, channel selection switch areas 163 and 164, a source selection switch area 165, and a power switch area 166. Each of these areas is a circular or rectangular area, and a black background is obtained by cutting a black film attached to the back surface 150B of the front panel 150 into a predetermined character or symbol shape at the center of the area. A symbol mark portion with transparent characters and symbol portions is provided.

  Each of these areas is formed about the size of a fingertip. Further, a symbol mark portion made up of predetermined characters and symbols formed in each region is formed slightly smaller than each switch region. Thereby, when each symbol mark part is contacted with a finger, not only the symbol mark part but most part of the switch area is brought into contact with the fingertip.

  In the present embodiment, “V” -shaped symbol marks are formed in the volume adjustment switch area 161 and the channel selection switch area 163, and “V” is turned upside down in the volume adjustment switch area 162 and the channel selection switch area 164. A symbol mark is formed in which two squares are overlapped in the source selection switch area 165, and a bar mark is superimposed on a circle in the power switch area 166 to symbolize power on / off. Is formed.

  The switch substrate 300 is placed on the substrate placement portion 173 of the frame 170. Electrode pads 321 to 326 are formed on the surface of the switch substrate 300. Each electrode pad 321 to 326 is formed at a position corresponding to each switch region 161 to 166 formed on the surface 150A of the front panel 150, and its shape and size also correspond to the shape of each switch region. , Circular or rectangular. Each of the electrode pads 321 to 326 is formed of a conductive material such as a silver paste or a conductive plastic film.

  At the time of assembly, the switch substrate 300 is attached to the back surface 150B of the front panel 150 in a state of being placed on the substrate placement portion 173 of the frame 170, whereby the electrode pads 321 to 326 are connected to the switch regions of the front panel 150. It is made to contact | adhere to the back surface of 161-166.

  As shown in FIG. 4, each of the electrode pads 321 to 326 includes first electrode pads 321A to 326A and second electrode pads 321B to 326B. That is, the electrode pad corresponding to one switch region is divided into two. That is, the volume adjustment switch area 161 will be described. The electrode pad 321 corresponding to the volume adjustment switch area 161 is divided into a first electrode pad 321A and a second electrode pad 321B. In particular, in this embodiment, the front panel 150 of the bathroom television apparatus 10 is used in a posture that is vertical to a horizontal plane, but each electrode pad 321 to 326 is a surface of the switch substrate 300 when in the posture. And is divided into two parts on the left and right along a line perpendicular to the tangent line between the front panel 150 and the horizontal plane.

  LED openings 331 to 336 penetrating the electrode pads and the switch substrate 300 are formed at the centers of the electrode pads 321 to 326, respectively. A flexible printed circuit board 310 is connected to the end of the switch substrate 300. The flexible printed circuit board 310 is connected to the control board 400 attached to the back side of the frame 170 through the FPC through-hole 174 that is bent and formed at the end of the board mounting portion 173.

  The control board 400 is for performing contact detection control on the capacitive contact switch used in this embodiment, and an electronic circuit (not shown) for detecting contact is provided on the board. Is provided. Further, on the control board 400, the switch areas 161 to 166 of the front panel 150, the LED openings 331 to 336 formed in the switch board 300, and the LED mount formed in the board mounting portion 173 of the frame 170 are provided. The LEDs 411 to 416 are arranged at positions corresponding to the positions of the through holes 175.

The LEDs 411 to 416 are, for example, white LEDs. When the LED is turned on, the light is irradiated to the back surface 150B of the front panel 150 through the LED through holes 175 of the substrate mounting portion 173 of the frame 170 and the LED openings 331 to 336 of the switch substrate 300, and the back surface 150B. By allowing light to pass through the surface 150A only in the portion where there is no black film affixed to the characters, the characters and symbols in each of the switch regions 161 to 166 appear to shine.

  Further, an infrared sensor 420 is disposed on the control board 400. The infrared sensor 420 is formed at a position corresponding to the position of the sensor through-hole 176 of the frame 170, detects an infrared control signal transmitted from a remote controller (not shown), and outputs it to a control circuit (not shown).

  The operation of the operation unit 160 in the bathroom television device 10 described above will be described below. In the following description, the operation for detecting contact with each of the switch areas 161 to 166 constituting the operation unit 160 is different in the control after the detection, and the operation of the detection itself is the same. Only detection of contact with respect to the adjustment switch region 161 will be described, and description of detection of contact with respect to the other switch regions 162 to 166 will be omitted.

  As shown in FIG. 5A, it is assumed that water droplets W adhere to the volume adjustment switch region 161 provided on the surface 150A of the front panel 150. Here, it is assumed that the water droplet W adheres to a part of the left side of the volume adjustment switch region 161. Since water is a conductive material, a capacitor is formed by the first electrode pad 321A through the water droplet W and the front panel 150, and the capacitance changes. By detecting this change by the electronic circuit of the control board 400, it can be determined that the conductive material is in contact with the first electrode pad 321A side of the volume adjustment switch region 161.

  However, since the water droplet W does not adhere to the right side of the volume adjustment switch region 161, the capacitance does not change on the second electrode pad 321B side, and the conductive volume does not change on the second electrode pad 321B side of the volume adjustment switch region 161. It is determined that the substance is not in contact.

  While it is determined that the conductive material is in contact with the first electrode pad 321A side of the volume adjustment switch region 161, the conductive material is not in contact with the second electrode pad 321B side. Judge that it is not contact.

  Moreover, even if the water droplet W adheres to the surface 150A of the front panel 150, it flows down by gravity. At this time, since the electrode pad 321 is divided into the first electrode pad 321A and the second electrode pad 321B along the vertical line, the water droplet W does not move across both the electrode pads. Therefore, even if the water droplet W moves, it is not erroneously determined that the contact is caused by the user's finger.

  On the other hand, as shown in FIG. 5B, it is assumed that the user's fingertip F contacts the volume adjustment switch region 161 provided on the surface 150A of the front panel 150. Since the switch area is approximately the same size as the user's fingertip, the user's fingertip F contacts almost the entire switch area. Then, a capacitor is formed between the fingertip F and the first electrode pad 321A via the front panel 150, and the capacitance changes. By detecting this change by the electronic circuit of the control board 400, it can be determined that the conductive material is in contact with the first electrode pad 321A side of the volume adjustment switch region 161.

  Furthermore, a capacitor is formed between the fingertip F and the second electrode pad 321B via the front panel 150, and the capacitance changes. By detecting this change by the electronic circuit of the control board 400, it can be determined that the conductive material has also contacted the second electrode pad 321B side of the volume adjustment switch region 161.

  Since it is determined that the conductive material is in contact with both the first electrode pad 321A and the second electrode pad 321B of the volume adjustment switch region 161, the electronic circuit of the control board 400 determines that this is contact with the fingertip of the user. To do. This determination does not need to be performed at exactly the same time, and it is only necessary to determine that the conductive material has contacted both the first electrode pad 321A and the second electrode pad 321B within a predetermined determination time.

  As described above, in this embodiment, the electrode pad corresponding to one switch region is divided into two, and when it is determined that the conductive material is in contact with the switch region corresponding to both sides thereof, If it is determined that the contact is made by the fingertip, and it is determined that the conductive material is in contact with the switch region corresponding to only one electrode pad, it is determined that the contact is not made by the fingertip, and no operation is performed.

  By doing so, even if a conductive material such as water droplets adheres to the surface 150A of the front panel 150, it can be prevented that the adhesion is erroneously determined to be contact by a fingertip.

  In the above embodiment, the control substrate 400 determines whether or not the conductive material has contacted the region corresponding to each divided electrode pad, and further, the electrode pad corresponding to one switch region is determined. It has been described that the control board 400 also determines whether or not contact with parts corresponding to all parts has been detected. However, the present invention is not limited to this. For example, when this electrostatic capacitance type switch is incorporated in an electronic device such as the bathroom television device 10, a control circuit such as a microcomputer is usually incorporated. Therefore, the determination performed by the control board 400 may be performed by the control circuit. In that case, the control circuit incorporated in the electronic device includes a detection unit. The detection unit determines whether or not the conductive material is in contact with the region corresponding to each divided electrode pad. It is determined whether or not the contact of the conductive material with the portions corresponding to all of the electrode pads corresponding to one switch region is detected at the same time.

  In the above embodiment, the case where the electrode pad corresponding to one switch region is divided into two has been described as an example. However, the present invention is not limited to this, and the electrode pad may be divided into three or more. Good. In that case, it is determined that the contact is made by the fingertip only when it is determined that the conductive material has contacted all the switch regions corresponding to the divided electrode pads. Alternatively, the contact with the fingertip may be determined only when it is determined that the conductive material has contacted the switch region corresponding to the preset number of electrode pads.

  In addition, although the case where the electrostatic capacitance type contact switch was applied to the bathroom television apparatus was described in the said Example, this invention is not limited to this, It is possible to apply to another electronic device.

10 Bathroom TV device 10
DESCRIPTION OF SYMBOLS 100 1st housing 110 Upper plate 120 Lower plate 130 Left side plate 140 Right side plate 150 Front panel 150A Front surface 150B Back surface 160 Operation part 161, 162 Volume adjustment switch area 163, 164 Channel selection switch area 165 Source selection switch area 166 Power switch area 170 Frame 171 Liquid crystal unit opening 172A, 172B Speaker opening 173 Substrate mounting portion 174 FPC through hole 175 LED through hole 176 Sensor through hole 200 Second housing 210 Upper plate 220 Lower plate 240 Right plate 250 Back plate 300 Switch substrate 310 Flexible printed circuit board 321 to 326 Electrode pad 321A to 326A First electrode pad 321B to 321B Second electrode pad 331 to 336 LED opening 40 The control board 411~416 LED
420 Infrared sensor 500 LCD unit

Claims (3)

  A plate or film-like dielectric having a first surface and a second surface, a switch area having a predetermined area provided on the first surface of the dielectric, and the switch area on the second surface of the dielectric An electrostatic contact switch comprising: an electrode pad closely in contact with a position and a shape corresponding to the sensor; and a detection circuit that detects whether a finger touches the switch region based on a change in capacitance. The electrode pad is divided into at least two for the one switch region, and the detection circuit has a conductive material for each of the switch regions corresponding to the at least two divided electrode pads. When it is determined that a conductive material has simultaneously contacted the switch areas corresponding to all the electrode pads within a predetermined determination time, a finger is applied to the switch area. Capacitive contact switch, characterized in that it is determined that contact.   The capacitive contact switch is incorporated in the electronic device such that the first and second surfaces of the dielectric form a predetermined angle with respect to a horizontal plane, and the electrode pad is disposed in the second surface. 2. The electronic device using the capacitive contact switch according to claim 1, wherein the electronic device is divided into at least two along a line perpendicular to a tangent line between the second surface and a horizontal plane. .   The electronic apparatus according to claim 2, wherein the electronic apparatus is a bathroom television device.

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