JPH0850526A - Input device - Google Patents

Abstract

PURPOSE:To provide the keyboard-less input device of simple configuration and high durability by fitting a line sensor onto one end face of a transparent plate, forming many grooves equipped with full reflecting planes on the other face and guiding reflected light from the full reflecting planes to the line sensor. CONSTITUTION:A light transmission plate 1 is a transparent plate, and a line sensor 2 is fitted onto its one end face 1a. Many grooves 6 are formed on an opposite face 1c of the light transmission plate 1, and all the grooves 6 are parallel with one end face 1a and provided with the full reflecting planes. When the face (the other face) on the side where no groove 6 is formed on the light transmission plate 1 is almost vertically irradiated with dotted beams such as laser beams, that dotted beam crosses the light transmission plate 1, arrives at an opposite face (one face) Lc and is reflected on the full reflecting planes of the grooves 6, and the reflected dotted beams are detected by the line sensor 2 on one end face 1a. In this case, the detecting points of the line sensor 2 correspond to the positions of reflecting points in the lengthwise direction of the grooves 6, and the strength of detection corresponds to the distance from the line sensor 2 to the reflecting points. Therefore, the coordinates in the X and Y directions of the light transmission plate 1 can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keyboardless input device using an optical pen. Generally, a keyboardless input device is used to simplify the operation of various dedicated terminals (for example, cash dispensers of banks). All you have to do is touch the pictures and letters on the screen, and people who are not familiar with keyboard operation can easily receive the required service.

[0002]

2. Description of the Related Art As an input device of this type, conventionally,
Known are a contact type and an electromagnetic induction type. In the contact point method, a transparent conductive pattern of an arbitrary shape is formed on both of two transparent films laminated with a minute gap between them, and the transparent film is pressed with a fingertip or pen tip to conduct the conductivity at the pressing point. The change in resistance between patterns is detected. The electromagnetic induction method is X, Y
A special pen for generating an alternating magnetic field is brought close to a plate in which a sense line is embedded in the direction, and the leakage magnetic flux is detected by the sense line.

[0003]

However, in the case of the contact type, repetitive mechanical stress acts between two transparent films, so that, for example, the transparent film and the conductive pattern may be separated. However, there is a problem that it is difficult to maintain normal operation for a long period of time. Further, the electromagnetic induction type is superior in durability to the contact type, but there is a problem that the structure is complicated and the price is inevitably high.

[0004]

Therefore, an object of the present invention is to provide a keyboardless input device having a simple structure and excellent durability.

[0005]

In order to achieve the above object, the present invention comprises a transparent flat plate and a line sensor attached to a predetermined one end surface of the flat plate. A large number of grooves parallel to the one end surface are formed, and the grooves have a total reflection surface that totally reflects the incident light from the other surface of the flat plate, and the reflected light from the total reflection surface is applied to the line sensor. It is characterized in that it is configured to guide and detect.

Alternatively, a hard-coated antiglare film is attached to the other surface of the flat plate. Alternatively, an optical filter that transmits only light of a predetermined wavelength is attached to one surface or one end surface of the flat plate. Alternatively, it is characterized in that two flat plates are laminated with the grooves orthogonal to each other.

[0007]

[Function] The surface of the flat plate on which the groove is not formed (the other surface)
When a point beam such as a laser beam is irradiated almost vertically, the point beam traverses the flat plate and reaches the opposite surface (one surface), but a large number of grooves having a total reflection surface are provided on the opposite surface. Since this is formed, this point ray is reflected (total reflection) by the total reflection surface thereof, and the reflected point ray is guided to one end surface of the flat plate and detected by the line sensor. Here, the detection point of the line sensor corresponds to the position of the reflection point in the longitudinal direction of the groove, and the detection intensity of the line sensor corresponds to the distance from the line sensor to the reflection point. Therefore, since the coordinates of the flat plate in the X and Y directions can be detected only by providing the above-mentioned simple structure, and since it has no mechanical parts such as contacts, it is a low-cost and keyboardless keyboard with excellent durability. An input device can be realized.

Alternatively, it is preferable to attach an antiglare film to the surface of the flat plate because scratches are less likely to occur and diffuse reflection of point rays can be prevented. Alternatively, it is preferable to attach an optical filter to the back surface or one end surface of the flat plate because light other than the predetermined wavelength can be cut and the influence of ambient light can be prevented. Or
It is preferable to intersect two flat plates and use each for detection in the X direction and detection in the Y direction because more precise coordinate detection can be performed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views showing an embodiment of an input device according to the present invention. First, the configuration will be described. In FIG.
1 is a light guide plate. For the light guide plate 1, for example, an acrylic resin or a glass plate is used, but the light guide plate 1 is not limited to this. The point is that a transparent flat plate formed of a homogeneous medium as a whole may be used.

The light guide plate 1 has a size equal to or slightly larger than the screen size of a liquid crystal panel or the like (not shown). For example, if the screen size of the liquid crystal panel or the like is 10 inches, then at least 10 inches. Is. Light guide plate 1
On one end face 1a (one end face corresponding to one of the left and right ends or one of the upper and lower ends of the liquid crystal screen) of the line sensor 2 such as CCD.
Is attached such that its longitudinal direction coincides with the longitudinal direction of the one end face 1a, and this line sensor 2 detects the position and intensity in the longitudinal direction of the point ray appearing on the one end face 1a of the light guide plate 1. is there.

Reference numeral 3 is an antiglare film attached to the surface (the other surface) 1b of the light guide plate 1. The antiglare film 3 is hard-coated and protects the surface 1b of the light guide plate 1 from scratches and the like. However, if such protection is not required, it may not be attached. Reference numeral 4 denotes an optical filter attached to the back surface (one surface) 1c of the light guide plate 1, and the optical filter 4 transmits only light corresponding to a wavelength of a point light beam described below or a wavelength range including the wavelength, This is for eliminating ambient light from sunlight and lighting equipment.
However, when it is used in a place where there is little ambient light, it need not be attached. The optical filter 4 may be interposed between the one end surface 1 a of the light guide plate 1 and the line sensor 2.

Reference numeral 5 is a light source (preferably a pen type) for generating a point beam (for example, a laser beam) having a predetermined wavelength.
A large number of grooves 6 are formed on the back surface 1c of the light guide plate 1, and all the grooves 6 are parallel to the one end surface 1a of the light guide plate 1. FIG. 2 is a sectional view of the light guide plate 1. Each groove 6 has a triangular cross-sectional shape. 1 for convenience
When the vertices of the cross section of one groove 6 are represented by symbols A, B, and C, each groove 6 has a first surface (total reflection surface) composed of sides AB.
6a and a second surface 6b composed of the side AC, the first surface 6a is located on the one end surface 1a side of the light guide plate 1, and these two surfaces 6a and 6b are in the front-back direction of the drawing, that is, the groove. 6 is continuous in the longitudinal direction.

Further, the light guide plate 1 between the adjacent grooves 6 is formed.
(A portion having a triangular cross section) is a so-called prism, and a line BC connecting the prism apex angles (angle ABA) is the surface 1b of the light guide plate 1 (or the film surface when the antiglare film 3 is attached). Is almost parallel to. Now, the angle ABC between the first surface 6a and the back surface 1c of the light guide plate 1 is α
If the angle is °, the minimum value of α ° is the critical angle of the light guide plate 1 (for example, about 42 ° when acrylic resin is used), and the maximum value is 90/2 ° (= 45 °). That is, α ° is an appropriate value in the range from the critical angle to 45 °. On the other hand, the angle ACB formed by the second surface 6b and the back surface 1c
Is β °, this β ° is a value as small as possible (for example, several degrees). Note that α ° and β ° shown in the figure are not set to actual angles for easy viewing.

Here, the critical angle means a limit angle at which a light ray incident on a medium (the light guide plate 1 in the above example) changes from refraction to total reflection at the interface between the medium and air (incident angle of light ray). ), And the refractive index of the medium is n, the critical angle is 1
/ N. In such a configuration, as shown in FIG. 1, the light source 5 is brought into contact with an appropriate position on the surface 1b of the light guide plate 1 (however, the surface of the antiglare film 3 when the antiglare film 3 is attached). When brought or brought closer,
A point ray from the light source 5 is emitted toward the inside of the light guide plate 1. At this time, it is desirable that the incident angle of the point light beam is approximately 0 °, that is, it is incident as perpendicularly as possible to the surface 1b of the light guide plate 1.

FIG. 3 is a conceptual diagram showing point rays inside the light guide plate 1. In this figure, 7 indicates incident light to the light guide plate 1, and 8 indicates reflected light (total reflected light) on the first surface 6a. FIG. 3 (a) shows that when α ° is 45 °,
(B) is a conceptual diagram when α ° is set to 43 °. In each drawing, the light guide plate 1 is made of acrylic resin (thus, the critical angle is about 42 °), and the incident angle of the incident light 7 is 0 °.

In FIG. 3A, an angle θa (incident angle) formed by the normal 6c of the first surface 6a and the incident light 7 is 45 °, and an angle formed by the normal 6c and the reflected light 8 is formed. θb (reflection angle) is also 45 °. Therefore, the reflected light 8 in this case
The angle formed by the incident light 7 is θa + θb, that is, 90 °. Therefore, the reflected light 8 travels in parallel with the back surface 1c of the light guide plate 1.

On the other hand, in FIG. 3B, the first surface 6a
The angle θa (incident angle) formed by the normal 6c and the incident light 7 is 43
The angle θb (reflection angle) formed by the normal 6c and the reflected light 8 is also 43 °. Therefore, the angle formed by the reflected light 8 and the incident light 7 in this case is θa + θb, that is, 8
Since it is 6 °, the reflected light 8 travels upward with an elevation angle of 4 ° with respect to the back surface 1c of the light guide plate 1.

One end surface 1a of the light guide plate 1 is located at the tip of the reflected light 8 traveling in parallel with the back surface 1c of the light guide plate 1 or at a slight elevation angle. Since the line sensor 2 is attached to the one end surface 1a, the position and intensity of the arrival point of the reflected light 8 on the one end surface 1a of the light guide plate 1 is detected by the line sensor 2. Therefore, the position of the reaching point is the first surface 6a.
Position of the reflection point at (that is, the incident position of the incident light 7)
And the intensity corresponds to the distance from the line sensor 2 to the reflection point of the first surface 6a (that is, the incident position of the incident light 7), so that the line sensor 2 causes the surface of the light guide plate 1 to end up. The irradiation position coordinates of the point ray in 1b can be detected.

Actually, unless the reflected light 8 is reflected by the first surface 6a closest to the one end surface 1a (that is, the first surface at the left end of FIG. 2), the reflected light 8 travels. At least one second surface 6b exists in the middle of the path, and the reflected light 8
Is light traveling in parallel with the back surface 1c of the light guide plate 1 or at a slight elevation angle, and the angle β ° formed between the second surface 6b and the back surface 1c of the light guide plate 1 is set to a value as small as possible. The reflected light 8 incident on the second surface 6b is totally reflected by the second surface 6b, and the totally reflected light is totally reflected again by the surface 1b of the light guide plate 1. That is, the actual reflected light 8 is the surface 1 b of the light guide plate 1.
While it is finally guided to the one end surface 1a of the light guide plate 1 while repeating total reflection between the rear surface 1c and the back surface 1c, some strength loss cannot be denied, but the detection by the line sensor 2 is performed without any trouble.

FIG. 4 shows an experimental example of strength measurement. In this example, an acrylic resin having a thickness of 2 mm is used for the light guide plate 1, and a large number of grooves 6 having a first surface 6a and a second surface 6b having α ° = 43 ° and β ° = 3 ° on the back surface 1c. Is formed. In addition, 9 is an optical fiber, 10 is an LED light source that generates red light of a single wavelength, and 11 is an optical power meter. FIG. 5 is a graph showing the experimental results, where the vertical axis is the optical power meter 1
1, the optical power P measured by 1 (unit: dBm), the horizontal axis is the distance L from the line sensor 2 to the tip of the optical fiber 9.
(Unit: mm). The dots in the graph are obtained by fixing the optical power at the tip of the optical fiber 9 to -14.35 dBm and measuring the optical power P at several sample distances L. As can be seen from this figure, the logarithm of the optical power P has linearity with respect to the distance L, and the distance L can be specified from the detection intensity of the line sensor 2.

The detection intensity of the line sensor 2 and the distance L
As shown in the above experimental example, a certain degree of correlation is established between the two, but since the relationship is not a perfect match, it is unavoidable that the accuracy is insufficient to specify a more accurate distance. In order to improve the accuracy, two light guide plates 1 may be prepared and the grooves 6 may be laminated so that the grooves 6 are orthogonal to each other. Since the coordinate X can be detected by the one light guide plate 1 and the coordinate Y can be detected by the other light guide plate 1, there is no need to rely on the relationship between the detection intensity of the line sensor and the distance, and the coordinate can be specified with higher accuracy. Can be done.

[0022]

According to the present invention, the coordinates of the flat plate in the X and Y directions can be detected only by providing a simple structure, and since no mechanical parts such as contacts are provided, the cost is low. A keyboardless input device with excellent durability can be realized. Or, if you attach an antiglare film to the surface of the flat plate,
Difficult to attach scratches, etc. to prevent irregular reflection of point rays.

Alternatively, if an optical filter is attached to the back surface or one end surface of the flat plate, it is possible to cut light other than a predetermined wavelength and prevent the influence of ambient light. Or, cross two flat plates,
If each is used for detection in the X direction and detection in the Y direction, more precise coordinate detection can be performed.

[Brief description of drawings]

FIG. 1 is a cutaway external view of a main part of an embodiment.

FIG. 2 is a cross-sectional view of a light guide plate according to an embodiment.

FIG. 3 is a conceptual diagram of total reflection of point rays inside a light guide plate according to an embodiment.

FIG. 4 is an experimental configuration diagram of an example.

FIG. 5 is a graph showing an experimental result of one example.

[Explanation of symbols]

 1: Light guide plate (flat plate) 1a: One end surface 1b: Front surface (other surface) 1c: Back surface (one surface) 2: Line sensor 3: Antiglare film 4: Optical filter 6: Groove 6a: First surface (total reflection) Surface) 7: Incident light

Claims (4)

[Claims] 1. A transparent flat plate and a line sensor attached to a predetermined one end surface of the flat plate, wherein a plurality of grooves parallel to the one end surface are formed on one surface of the flat plate. An input device having a total reflection surface that totally reflects incident light from the other surface of the flat plate, and configured to guide reflected light from the total reflection surface to the line sensor for detection. 2. The input device according to claim 1, wherein a hard coat antiglare film is attached to the other surface of the flat plate. 3. The input device according to claim 1, wherein an optical filter that transmits only light of a predetermined wavelength is attached to one surface or one end surface of the flat plate. 4. The input device according to claim 1, wherein two flat plates are laminated with the grooves orthogonal to each other.