JPH02299110A - Touch switch mechanism - Google Patents

Abstract

PURPOSE:To obtain high reliability and touch feeling by receiving the light at the portion where a detecting sheet-shaped object is closely stuck to a trans parent light-guiding substrate, and detecting the position. CONSTITUTION:A transparent light-guiding substrate 1 guides the light from a light source 3 to its incident end 1A. The total reflection of the incident light is determined by the difference between the refraction factor of the sub strate 1 and the refraction factor of the boundary face. Only when a detecting sheet-shaped object 2 is overlapped on the substrate 1 and the sheet-shaped object 2 is pressed, the total reflection collapses at this portion, and the light is received. The light reception is detected by a linear sensor arranged on the periphery of the sheet-shaped object 2. A touch type switch is obtained.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is used in combination with a display such as a CRT or liquid crystal display, and the user receives a signal by touching the image with a finger or a pen while viewing the image. This invention relates to a transparent type touch switch mechanism that allows input.

(Prior Art) As a touch switch used for the above-mentioned purpose, a full charge capacity detection method as shown in Japanese Patent Publication No. 59-23411, etc., and a resistive film method as shown in Japanese Unexamined Patent Publication No. 59-114278, etc. are known. In addition to this, there is also a photoelectric method that uses touch VRL to block between the light receiving and emitting elements, a sound wave generator,
Acoustic systems using receivers are known.

(Problems to be Solved by the Invention) The various touch switches described above have been developed for a short period of time, so there is still much room for improvement, but they have become mainstream because they have a simple structure, are inexpensive, and provide a touch sensation. Even with the resistive film method mentioned above, problems remain, such as the contact interface being susceptible to deterioration such as oxidation and local peeling, coloring of the clay, and insufficient transparency.

In view of this situation, the present invention is an attempt to provide a transparent type touch switch mechanism that is highly reliable, low cost, and provides a touch sensation using a method of detecting signals by transmitting light.

(Means for Solving the Problems) That is, the present invention has been made to achieve the above problems, and its gist is that it consists of a transparent light guide substrate and a detection sheet, and in its initial state, The transparent light guide substrate is overlaid so that the light from the transparent light guide substrate is not transmitted to the detection sheet, and the light is transmitted only in the detection state when they are in close contact with each other, and the transparent light guide substrate is supplied from the light source. The touch panel is shaped so as to guide light in a planar direction, and the detection sheet-like material receives light at a portion in close contact with the transparent light guide substrate and is shaped so as to detect the position. It's in the switch mechanism. In the present invention, the touch switch mechanism refers to a signal input portion constituting a touch switch panel, and signal transmission and processing are incorporated into this to complete a switch device.

(Example) The present invention will be described below with reference to drawings of embodiments.

First, based on FIGS. 1 to 3, which are typical examples of the present invention, b
To explain, in the figure, (1) is a transparent light guide substrate, and (2) is a detection sheet. Among these, transparent light guide substrate (1)
For example, a transparent methacrylic resin plate with a thickness of 10 m (20 m in length)
0 m, width 260,), and a light source (5) such as a K fluorescent lamp (8W) or a halogen lamp is placed at the entrance end (1A) at the - side end, and from the entrance end (1A). It is designed to guide the incident light. The incident light is
As shown in the figure, the light propagates in the plane direction while repeating total reflection, and this total reflection is determined by the difference between the refractive index of the transparent light guide substrate (1) serving as a medium and the refractive index of the interface. For example, when methacrylic resin with a refractive index of 1.49 is in contact with air, the critical angle is approximately 42°, and the thickness of the air layer required to cause total reflection is 1/4 to 1/2 the wavelength. However, when the same methacrylic resin is in contact with silicone oil with a refractive index of 1.4, the critical angle is about 70°, and the minimum thickness of the silicone oil to cause total reflection is 1/2 ~
One wavelength is required.

In other words, the critical angle for causing total reflection is given by: tc = 5in-j = J, where the refractive index of the transparent light guide substrate is nl + and the refractive index of the fluid located at the interface is n2, and the critical angle for total reflection is Treatment to maintain functionality - Fluid thickness, or evanescence
rxtWave) is known to be proportional to where λ is the wavelength.

By setting the transparent light guide substrate (1) under such conditions that cause total reflection, the light propagates through the substrate in the planar direction and does not exit the substrate unnecessarily.

A detection sheet (2) made of a transparent methacrylic resin having a thickness of α81111+ is superimposed on the transparent light guide substrate (1) of the present invention, but in the initial state when the switch is off, all of the above The reflected state is maintained so that it is not transmitted to the detection sheet (2), and the detection sheet (2) is suppressed in order to turn on the detection signal FIC as shown in Figure 3. (for example, a force of about 20 to 302 degrees), total reflection breaks down in this part and this light is received.

Then, by detecting the light received by the detection sheet (2) with a line sensor such as a photodiode array placed around the periphery of the sheet (2), the υ touch type It can be a switch. When the pressing force is released, the detection sheet-like object (2) returns to its original initial state, and the switch assumes the shape μp.

In the above figure, (4) is a reflective cover for the light source, and (5) is a reflective cover for the light source.
) is a case with a reflective inner surface, and (6) is a transparent adhesive tape that also serves as a spacer. As mentioned above, the distance between the transparent light guide substrate (1) and the detection sheet (2) should be at least one wavelength of light, so even if there is no special spacer, it will be natural to It has been confirmed that there is a gap necessary for total reflection, but it is practical to use adhesive tape or the like to also secure the detection sheet (2) as shown in the figure to ensure stability.

As the material for the transparent light guide substrate (1) used in the present invention, the above-mentioned methacrylic resin is particularly excellent in terms of transparency and processability, but other materials such as polycarbonate resin, vinyl chloride resin, styrene resin, etc. Transparent synthetic resin can be used, and in some cases glass can also be used. Further, this transparent light guide substrate (1) is not limited to a plate shape, but may be a curved shape, and may be a thinner sheet shape as long as it has light guiding performance. A coating or a coating of a low refractive index material having an antireflection function may be provided.

The material of the detection sheet (2) used in the present invention is also a transparent synthetic resin sheet similar to the transparent light guide substrate (1),
Film or tape is used. In this case, the surface of the material is also resistant! An abrasive coating or a coating of a low refractive index material having an antireflection function may be provided.

4 to 10 show another embodiment of the present invention, which will be described in sequence.

FIG.
This is an example in which the detection sheets (2) of the locks) are arranged and overlapped with transparent adhesive tape (as shown) at intervals of, for example, one wavelength or more to prevent light from transmitting to each other. The light received by the sheet-like material (2) travels in the longitudinal direction of the strip, and signals can be detected in this direction.

Figures 5 and 6 are examples in which the example in Figure 4 is further improved, and includes a band-shaped object (57) for detection (2) a material (7) that prevents light from passing through each other, such as a material with a low refraction. Detection sheet-like material (2)
The transmission and reception of signals received with good morphology is also ensured.

In the example shown in Figure 7, signals are transmitted and received in two axial directions, whereas in the above example, signals are transmitted and received in two axial directions, and similarly, they are connected via a substance (7) that does not transmit light. Two detection sheets (2) are arranged perpendicularly to each other, which allows signals to be sent and received in two axes, that is, in the vertical and horizontal directions. In this case, the two detection sheets (2) and the transparent light guide substrate (1) are overlapped to prevent light from transmitting in the initial state, but when they are in close contact, they receive light. I miss K. Note that the material (7) used in these examples that prevents light transmission is a transparent material with a lower refractive index than the material of the detection sheet (2), for example, the detection sheet (2) is made of methacrylate. When using resin, fluoropolymer or silicone polymer can be used. In this case, the low refractive index material 2 may be placed only on the surfaces in contact with the detection F) contacting object (2) of i, and the light absorbing material may be interposed between them for connection.

8 to 10 show another example of how light is incident on the transparent light guide substrate (1), and FIG. 8 shows the transparent light guide substrate (1).
1) An example in which a group of optical fiber rods (8) are interposed between the incident end (1A) and the light source (3) to diffuse the light in the lateral direction so that it becomes omnidirectional. Figure 9 shows that the incident end (1) of the transparent light guide substrate (1) is used to achieve the same effect.
This is an example in which a small cylindrical lens (9) group is formed in A). FIG. 10 shows an example in which light is incident from both ends and the center of the transparent light guide substrate (1). Both ends and the center entrance end (one person) have concave curved surfaces, and the center light source 6) is provided with an opposite surface (10) for branching light and a reflective cover (11). In this way, light can be incident on the transparent light guide substrate (1) of the present invention from other than one end, but this incident end may be the opposing side edge or the surrounding side edge.

Although the illustrated examples have been described above, the present invention is not limited to these examples, and it is also possible to use light other than visible light, such as infrared light, for the light incident on the transparent light guide substrate (1), or to use light for detection. A substance having a lower refractive index than these may be interposed between the sheet-like materials (2) and between these and the transparent light guide substrate (1). In addition, as shown in the figure, the sheet-like material (2) for detecting the belt-like object (2) and the material (7), which prevents light transmission, are slightly raised to quickly connect each other. It can also make it easier for people to escape.

(Detailed Description of the Invention) Since the present invention has the structure as described in detail above, it has a simple structure but can operate reliably, has high transparency, does not change in color tone, and is resistant to changes over time. , and it also resists electrical noise.The touch feeling is also reliable.
Moreover, there is an advantage that a highly economical touch switch mechanism can be obtained that can be applied not only to flat surfaces but also to curved surfaces.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing a typical example of the present invention, #¥2
Figures 3 and 3 are partially enlarged cross-sectional views showing their operating states;
Figures 4 and 5 are partial perspective views showing another example of the present invention, pP, Figure 6 is a partial enlarged perspective view of the detection sheet used in Figure @5, and Figure 7 is a perspective view of the present invention. FIGS. 8 to 10 are a partial perspective view and a sectional view showing another example of the transparent light guide substrate used in the present invention. (1)...Transparent light guide substrate, (2)...Sheet-like object for detection, (3)...Light source tail l concave jJ) 3 figure red 4 figure #6 figure Qin 7 figure not a figure/A $, q must be written O concave

Claims (1)

[Claims] 1. Consisting of a transparent light guide substrate and a detection sheet, in the initial state, light from the transparent light guide does not transmit to the detection sheet, but in the detection state when they are in close contact with each other. The transparent light guide substrate is designed to guide the light supplied from the light source in the plane direction, and the detection sheet is in close contact with the transparent light guide substrate. A touch switch mechanism characterized in that the position can be detected by receiving light at the touched part. 2. The touch switch mechanism according to claim 1, wherein a light source is disposed at at least one side end of the transparent light guide substrate. 3. Claim 1 or 2, characterized in that a large number of strips extending in one direction are arranged in at least one layer in a planar manner so that no light is transmitted to each other to constitute the detection sheet-like object. Touch switch mechanism as described in section.