JP2001291458A - Optical touch switch device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem on a conventional optical touch switch device used for a function part, for example, an optical touch switch device consisting of ten switches, that ten light emission elements and ten light receiving elements are required to produce an increase in a cost and the function part, if having a level difference, prohibits the use of the optical touch switch. SOLUTION: A light emitting element is provided for each switch and a light conductor is provided between the light emitting element and a switch function plane so that a light emitted by the light emitting element is transmitted through the light conductor and emitted to the outside if a finger approaches or contacts the function plane. If the finger approaches or contacts with the function plane, the light is reflected by the finger and the reflected light is guided to the light receiving element by the light conductor so that the operation of the switch can be determined by the output of the light receiving element. The shape of the light conductor is changed in the thickness perpendicular to the function plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to, for example, home appliances,
The present invention relates to a touch switch provided in a vending machine, an in-vehicle device, and the like, and more particularly, to an optical touch switch device.

[0002]

2. Description of the Related Art An optical touch switch of this type will be described with reference to FIGS. FIG. 6 is a sectional view 80 of the optical touch switch, where 81 is a light emitting element, 82 is a light receiving element, 8
Reference numeral 3 denotes a printed circuit board on which the light emitting element and the light receiving element are mounted; 84, a switch cover made of a translucent resin; and 85, a device operation panel. A plurality of such optical touch switches are arranged on the operation surface to constitute an optical touch switch device. Input information is given to various devices using this switch.

FIG. 7 is an explanatory diagram in the case where the switch is not operated. Light 86 is emitted from the light emitting element 81, and this light passes through the switch cover 84, so that it does not enter the light receiving element 82. FIG. 8 is an explanatory diagram when the switch is operated, and the finger F is in contact with the surface of the switch cover 84.
In this state, the light 86 emitted from the light emitting element 81 is reflected by the finger F in contact with the surface of the switch cover 84 and enters the light receiving element 82. The incident light is received by the light receiving element, a photocurrent is generated, and processed by a detection circuit (not shown) to determine whether a switch operation has been performed. Since such switches use light, they are resistant to electrical noise and have a long switch life. Therefore, such switches are often used in devices that require such characteristics.

[0004]

However, a plurality of optical touch switches are used in such an operation section. For example, an operation section in which 10 switches are arranged requires 10 light emitting elements and 10 light receiving elements. And the cost was high. If the operation surface has a planar shape, a conventional touch switch can be used. However, in the case of an operation portion having a non-planar step, the interval between the printed circuit board 83 and the operation surface is not constant. I couldn't do that. In some cases, it is difficult to operate a nighttime switch because the surroundings of the switch are dark. Further, when the switch is operated, it is necessary to provide a special indicator light for confirming whether the switch operates normally. The present invention is intended to solve these problems.

[0005]

The present invention is configured as follows to solve the above-mentioned conventional problems.

(1) In an optical touch switch device comprising a plurality of switches using a light emitting element and a light receiving element, a light emitting element is provided for each switch, and a light guide is provided between the light emitting element and the switch operation surface. When there is no approach or contact of a finger on the operation surface, the light emitted from the light emitting element is transmitted through the light guide and emitted to the outside. When there is an approach or contact of the finger on the operation surface, the light is reflected by the finger, and the reflected light Is guided to the light receiving element by the light guide, and the switch operation is determined based on the output of the light receiving element.

(2) In the optical touch switch device described in the item (1), the light emitting elements are arranged so that the light emitted from the light emitting elements is vertically incident on the light guide.

(3) The optical touch switch device described in (1) or (2) can be adapted to a stepped operation surface by changing the thickness of the light guide in the direction perpendicular to the operation surface.

(4) In the optical touch switch device according to any one of (1) to (3), which switch has been operated is determined from the light emission timing of the light emitting element.

(5) The optical touch switch device according to any one of (1) to (4), wherein the switch is illuminated or various displays are made using a time other than the light emission time of the light emitting element for detecting the switch operation.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view 1 for explaining the principle of an optical touch switch according to the present invention. 2
Is a light emitting element (infrared light emitting elements are often used), 3 is emitted light emitted from the light emitting element, 4 is a light receiving element for detecting light emitted from the light emitting element, and 5 is a light guide. , 6
Is a light shielding member, and this light shielding member is provided to prevent light emitted from the light emitting element from directly entering the light receiving element, and is provided as necessary. In FIG. 1, the light emitted from the light emitting element passes through the light guide and is emitted to the outside, and does not enter the light receiving element 4.

FIG. 2 is a sectional view when the optical touch switch of FIG. 1 is operated. The finger F is brought into contact with the light guide surface arranged on the upper surface of the light emitting element 2. The outgoing light 7a emitted from the light emitting element 2 is reflected by the finger F, and the reflected light is diffused light that spreads in all directions, and a part of the light satisfies the total reflection condition and becomes the total reflected light 7b, and becomes a light guide. The light travels inside and enters the light receiving element 4 provided near the end face of the light guide. Most of the light 7c that does not satisfy the condition for total reflection is emitted to the outside of the light guide, and some light is reflected inside the light guide and enters the light receiving element.

The light-receiving surface of the light-receiving element has an end face which is perpendicular to the traveling direction of the totally reflected light so that the light-receiving surface of the light-receiving element can receive more totally reflected light. Is cut at a predetermined angle θ, and a light receiving surface is arranged parallel to the surface.

The light incident on the light-receiving element generates a photocurrent at the light-receiving element, and the photocurrent is sent to a detection circuit (not shown), where it is processed to determine whether the switch has been operated.

As described above for one optical switch, as compared with the conventional example and the present invention, the light emitted from the light emitting element is reflected by the finger F in the conventional example, and the reflected light is The light passes through the cover and enters the light receiving element. In the present invention, the light reflected by the finger F enters the inside of the light guide, and the light satisfying the total reflection condition is incident on the light receiving element. The use of the light-emitting element and the light-receiving element is the same in any of the configurations, and differs in that the light transmitted through the switch cover or the light totally reflected by the light guide is used.

The present invention is characterized in that the principle of the switch described with reference to FIGS. 1 and 2 is applied to an operation unit including a plurality of switches used in a device or the like. FIG. 3 is a plan view of such an operation unit when the operation unit is constituted by four switches A, B, C, and D to simplify the description. FIG. 4 is a sectional view taken along line XX of FIG. In these drawings, the light blocking member is omitted. In FIG. 4, 8a and 8b are light emitting elements, 8a is a light emitting element of an A switch, 8b is a light emitting element of a B switch, and 4 is a light receiving element.

The A switch comprises a light emitting element 8a, a light receiving element 4 and a light guide 5, and the B switch comprises a light emitting element 8b, a light receiving element 4 and a light guide 5. The light receiving element 4 and the light guide 5 are commonly used.

FIG. 4 shows a case where the B switch is operated. When the finger F contacts the surface of the light guide disposed on the upper surface of the light emitting element 8b, the light 7a emitted from the light emitting element 8b
Is reflected by the finger F, and among the reflected light, reflected light 7b satisfying the total reflection condition travels inside the light guide, the light is incident on the light receiving element, and the light receiving element 4 generates a photocurrent, The switch operation is detected by the current.

Similarly, when the finger F is brought into contact with the surface of the light guide disposed on the upper surface of the light emitting element 8a, the light emitted from the light emitting element 8a is reflected by the finger F, and a part of the reflected light is reflected by the light guide. And enters the light receiving element 4 to generate a photocurrent. The operation of the B switch is similarly detected by the current. The same applies to the C switch and the D switch.

In these operations, the light emitting elements do not emit light simultaneously, but four light emitting elements emit light in order. Therefore, only one of them emits light and does not emit light at the same time. The light emission timing is controlled by a control circuit (not shown).

By doing so, it is possible to determine which switch has been operated by checking the timing at which the photocurrent is generated in the light receiving element 4. That is, the light emission timing at which the light emitting element of the switch A emits light, the light emission timing at which the light emitting element of the switch B emits light, the light emission timing at which the light emitting element of the switch C emits light, or D
The control circuit can easily determine whether the light emitting element of the switch emits light or not. As described above, if the principle of the present invention is used, the number of switches can be similarly set whether it is 10 or 20. In other words, the number of light emitting elements is required by the number of switches, but the number of light receiving elements may be one.

Generally, a touch switch device used for an operation unit is often used with switches arranged in a matrix, but the present invention can be easily applied to a switch device having such a configuration. In this case, one light-receiving element may be provided for a plurality of light-emitting elements. However, when the light-receiving signal is small, one light-receiving element is arranged in each row in order to increase sensitivity, and detection is performed from any of the light-receiving elements. do it.

In the above description, when the finger is brought into contact with the surface of the light guide, the light emitted from the light emitting element is reflected by the finger,
It has been described that the reflected light travels inside the light guide and enters the light receiving element, and the operation of the switch is detected. However, even if the finger does not necessarily come into contact with the surface of the light guide, as the finger approaches, the light reflected by the finger Increase. Therefore, the light incident on the light receiving element also increases as the finger approaches, and it can be detected that the finger approaches the light guide.

Although one light receiving element has been described, if the number of switches is large and the operation unit is large, the amount of light incident on the light receiving element may be small and the detection capability may be reduced. In such a case, as described for the switch devices arranged in a matrix, the number of light receiving elements may be increased if necessary.

The direction of the emitted light of the light emitting element is desirably perpendicular to the light receiving surface of the light guide for receiving the emitted light. If the direction is inclined, there is no approach or contact of a finger for operation. In this case, a part of the light emitted from the light emitting element generates reflected light inside the light guide, and the reflected light is incident on the light receiving element to lower the detection sensitivity. That is, there is no difference in the output of the light receiving element between when the switch is operated and when it is not operated. For this reason, in order to increase the detection sensitivity, it is desirable to arrange the light emitting elements so that the emitted light direction is perpendicular to the light receiving surface of the light guide.

Although the conventional optical touch switch cannot be used when the operation surface has a step in the related art, the present invention can easily cope with it by changing the shape of the light guide. FIG. 5 shows such an embodiment. Light emitting elements 8a and 8b and light receiving element 4 are mounted on printed circuit board 9. The operation surface of the device front panel 10 is not a flat surface as shown in FIG. Light guide 1 arranged between light emitting / receiving element and operation surface
As shown in FIG. 1, the thickness in the direction perpendicular to the operation surface is changed according to the distance between the operation surface and the printed circuit board. With this configuration, light emitted from the light emitting element can be guided to the light receiving element via the light guide.

The detection of whether or not the switch is operated is performed by short-time light emission by the light emitting element corresponding to the switch. That is, when an output is detected from the light receiving element during the light emission time, a switch operation is performed, and when no output is detected, no operation is performed. The light-emitting time of the light-emitting element for detecting the switch operation is short, and most of the time when no light is emitted.
The inventor considered using this idle time to perform illumination and display around the switch.

By using the light emitting element as a visible light emitting element and emitting light during idle time, it is possible to illuminate the area around the switch so that the switch can be easily operated at night. In addition, when the switch is operated, it is possible to display a response indicating whether the switch operates normally.
In addition, a display other than the response display can of course be performed.
In addition, both the illumination and the display can be performed simultaneously by blinking the response display for a short time while the light emitting element is turned on for the illumination.

[0029]

As described above, in an operation section of a device or the like in which a plurality of optical switches using light emitting elements and light receiving elements are arranged, for example, in an operation section in which 10 optical switches are arranged, conventionally 10 Since the light emitting element and ten light receiving elements were used, the material cost was high and the operation unit was expensive. However, according to the present invention, ten light emitting elements and one light receiving element were used.
Since it can be composed of one light receiving element and one light guide, the material cost is low and the cost of the operation unit can be reduced.

Further, according to the present invention, it is possible to easily cope with an operation surface having a step by changing the shape of the light guide in the direction perpendicular to the operation surface. Further, the light emitting element can be caused to emit light to illuminate the switch by using the idle time when the light emitting element does not emit light, and the light emitting element can be used to display whether or not the switch operates normally. Can also emit light.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical touch switch according to the present invention.

FIG. 2 is a sectional view when the optical touch switch of the present invention is operated.

FIG. 3 is a front view of an operation unit using four optical touch switches of the present invention.

FIG. 4 is a view of operating a touch switch in the XX cross-sectional view of FIG. 3;

FIG. 5 is a diagram showing a touch switch being operated in a sectional view of the operation unit having a step;

FIG. 6 is a sectional view of a conventional optical touch switch.

FIG. 7 is an explanatory diagram when a conventional optical touch switch is not operated.

FIG. 8 is an explanatory view when a conventional optical touch switch is operated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cross-sectional view of an optical touch switch 2 Light emitting element 3 Light emitted from a light emitting element 4 Light receiving element 5 Light guide 6 Light blocking member 7a Light emitted from a light emitting element 7b Total reflected light 7c Light emitted out of a light guide 8a Light emission from an A switch Element 8b Light emitting element of B switch 9 Printed circuit board 10 Operation panel of device 11 Light guide A to D switch 80 Cross section of optical switch 81 Light emitting element 82 Light receiving element 83 Printed circuit board 84 Switch cover 85 Operation panel 86 Light emitting element emitting light

Claims (5)

[Claims] 1. An optical touch switch device comprising a plurality of switches using a light emitting element and a light receiving element.
A light-emitting element is provided for each switch, and a light guide is provided between the light-emitting element and the switch operation surface. The light emitted from the light-emitting element is transmitted to the outside through the light guide when no finger approaches or touches the operation surface. The light is emitted, and when a finger approaches or touches the operation surface, the light is reflected by the finger, the reflected light is guided to a light receiving element by a light guide, and a switch operation is determined based on the output of the light receiving element. Optical touch switch device 2. The optical touch switch device according to claim 1, wherein the light emitting elements are arranged such that light emitted from the light emitting elements is perpendicularly incident on the light guide. 3. The optical touch switch device according to claim 1, wherein a thickness of the light guide in a direction perpendicular to the operation surface is changed so that the operation surface can correspond to a stepped surface. 4. The optical touch switch device according to claim 1, wherein which switch has been operated is determined based on the light emission timing of the light emitting element. 5. A light-emitting element for detecting a switch operation, and the light-emitting element emits light for illuminating the switch or performing various displays at times other than the light-emitting time. The optical touch switch device according to claim 1.