JP3753564B2 - Touch panel coordinate detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coordinate detection apparatus for a touch panel.
[0002]
[Prior art]
Conventionally, various types of touch panel coordinate detection apparatuses are known. Among them, two optical units having a light emitting part and a light receiving part are arranged at different positions on the peripheral part of the touch panel, and a reflective part for reflecting the light emitted from the light emitting part in the emission direction is further provided on the touch panel. The touch panel of the structure arrange | positioned in the peripheral part of is widely prevailing.
[0003]
In a touch panel provided with such an optical unit and a reflective part, light from the light emitting part is emitted in parallel and in a fan shape along the panel surface of the touch panel, and the light is reflected by the reflective part and then the light emitting part. The light is received by the light receiving unit. Then, when a certain position on the panel surface is touched with a finger or the like, the light passing through the position is blocked by the finger, and a spot where no light is received on each of the two light receiving portions is generated, and the spot is detected. Thus, the coordinates indicating the position touched with a finger or the like on the panel surface are detected.
[0004]
[Problems to be solved by the invention]
The optical unit is formed with an entrance through which light emitted from the light emitting unit and light reflected by the reflecting unit enter and exit. If foreign matter such as dust enters the optical unit through this doorway and adheres to the light emitting part, light receiving part, and other optical components, the light emitted toward the reflecting part may become uneven or The light receiving accuracy is reduced, and the accuracy of coordinate detection is lowered.
[0005]
In addition, when a foreign object such as a user's finger or a rod-like member enters from the entrance / exit, the light emitted toward the reflecting portion becomes uneven due to the fingerprints or oil adhering to the optical components in the optical unit, or the light receiving portion In addition, the light receiving accuracy at the light receiving portion is lowered, and further, the optical component is pushed and displaced, so that the light receiving accuracy at the light receiving portion is lowered, and the coordinate detection accuracy is lowered.
[0006]
Therefore, the present invention provides a coordinate detection device for a touch panel that can prevent foreign objects from entering the optical unit from the light entrance and exit formed in the optical unit and perform coordinate detection with high accuracy. With the goal.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, a plurality of optical units including a light emitting part and a light receiving part arranged at different positions on the outer peripheral edge of the touch panel, and an emission from the light emitting part arranged at the outer peripheral edge of the touch panel. by having a reflective portion of the retro-reflecting to the emission direction of light, while receiving the light reflected by the reflection portion by the light receiving portion, wherein by detecting the received light was prevented position In the touch panel coordinate detection device for detecting coordinates indicating the touched position on the panel surface of the touch panel, the light exiting from the light emitting unit and the light reflected by the reflecting unit enter and exit the optical unit. A protective member that transmits light to the portion and prevents entry of foreign matters is provided, and the protective member is subjected to a shading process that makes the light transmission amount substantially uniform over the entire surface.
[0008]
Therefore, by providing a protective member at the entrance / exit of the optical unit, entry of foreign matter into the optical unit, for example, entry of dust, dust, a user's finger, etc., is prevented. For this reason, foreign matter that has entered the optical unit adheres to the light emitting unit, the light receiving unit, and other optical components, and displacement of the optical component due to the foreign matter hitting is prevented, resulting in a reduction in luminous efficiency and light receiving performance. Is prevented, and the accuracy of coordinate detection is increased. On the other hand, the light emitted from the light emitting part passes through the protective member and travels toward the reflective part, and the light reflected by the reflective part passes through the protective member and is received by the light receiving part. There is no reduction in the accuracy of coordinate detection.
According to the first aspect of the present invention, since the protective member is subjected to a shading process in which the light transmission amount is substantially uniform over the entire surface, the light reception amount at the light receiving unit is uniform over the entire area of the light receiving unit. The accuracy of detecting the coordinates of the peripheral edge of the is increased.
[0009]
According to a second aspect of the present invention, in the first aspect, wherein the protective member, when the light passes through the protective member, in the direction in which light reflected by the protective member is not received by the light receiving portion It is disposed at a predetermined angle in the direction of reflection.
[0010]
Therefore, when the light emitted from the light emitting part passes through the protective member, a part of the light is reflected by the protective member, but the reflected light is reflected in the direction not received by the light receiving part. The erroneous detection of coordinates due to the reflected light received by the light receiving unit is prevented.
[0011]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the protective member is transparent.
[0012]
Therefore, this protective member increases the transmittance of the light emitted from the light emitting unit and the light reflected by the reflecting unit, and the accuracy of coordinate detection is increased.
[0013]
According to a fourth aspect of the present invention, in the first, second, or third aspect of the present invention, the protective member is made of glass.
[0014]
Therefore, since glass has high mechanical strength and high flatness, the light transmitted through the glass is difficult to diffuse and maintains straightness, so that the light receiving accuracy at the light receiving portion is increased and erroneous detection of coordinates is prevented. The
[0017]
According to a fifth aspect of the present invention, in the first, second, third, or fourth aspect of the present invention, the protective member transmits light in a wavelength region of light emitted from the light-emitting unit and transmits light in another wavelength region. It has an optical characteristic that suppresses transmission of light.
[0018]
Therefore, even if disturbing light enters toward the entrance / exit of the optical unit, the disturbing light is prevented from passing through the protective member, preventing erroneous detection of disturbing light at the light receiving unit, and high coordinate detection accuracy. Become.
A sixth aspect of the present invention is the coordinate detection device according to any one of the first to fifth aspects, wherein the optical unit includes a diffusing lens that diffuses the light emitted from the light emitting unit. To do.
According to a seventh aspect of the present invention, in the coordinate detection device according to the sixth aspect, the protective member is subjected to a shading process so that the amount of light diffused by the diffusing lens is uniform over the entire surface. Features.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the basic configuration of the present invention. The optical unit 2 is disposed at each of the two corners that are the outer peripheral edge of the touch panel 1 having a rectangular outer shape, and the reflecting part 3 is disposed at the three sides that are the outer peripheral edge of the touch panel 1. Has been. The reflection unit 3 uses a retroreflective sheet in which a high-density trihedral cube is disposed inside the sheet and reflects incident light toward the light source. A computing unit 4 is connected to the two optical units 2, and the computing unit 4 is connected to a personal computer 6 via an interface unit 5.
[0020]
2 is a longitudinal side view showing the internal structure of the optical unit 2, and FIG. 3 is a bottom view thereof. In the optical unit 2, a storage space surrounded by the first holding plate 7, the second holding plate 8, the housing 9 and the back plate 10 is formed. In this storage space, the light emitting unit 11 that emits laser light and the laser light emitted from the light emitting unit 11 are diffused in parallel to the panel surface 1a of the touch panel 1 and in a fan shape (90 ° in this case). A diffusing lens 12, a half mirror 13 that transmits ½ of the incident light straight and reflects the remaining half, a reading lens 14 that forms an image of incident light, and a laser reflected by the reflecting unit 3 A CCD 15 or the like that is a light receiving unit that receives light is accommodated. A circuit board 16 that drives and controls the light emitting unit 11 is connected to the light emitting unit 11. A circuit board 17 for driving and controlling the CCD 15 is connected to the CCD 15.
[0021]
In the optical unit 2, an entrance 18 through which laser light enters and exits is formed at a position that is one end of the storage space and faces the reflecting portion 3. The entrance / exit 18 is provided with a transparent glass plate 19 that is a protective member that transmits light and prevents entry of foreign matter (for example, dust, dust, a finger or a stick-shaped member of a touch panel user). The glass plate 19 is disposed at a predetermined angle so that the light reflected by the glass plate 19 is reflected in a direction not received by the CCD 15 when the laser light traveling toward the reflecting portion 3 is transmitted through the glass plate 19. ing. Here, it is inclined by 6 ° with respect to the direction perpendicular to the panel surface 1a.
[0022]
The circuit board 16 for driving and controlling the light emitting unit 11 is fixed to the second holding plate 8, and the second holding plate 8 is fixed to the first holding plate 7 with screws 20. Further, the plate spring 21 is fastened and fixed by the screw 20, and the light emitting portion 11 is pressed against the second holding plate 8 by the plate spring 21 and positioned.
[0023]
The second holding plate 8 is formed with two adjustment long holes (not shown), and the first holding plate 7 is formed with a round hole (not shown) at a position overlapping these adjustment long holes. Has been. Then, by rotating an eccentric pin (not shown) having the tip portion fitted in the round hole and the eccentric portion fitted in the adjustment slot, the second holding plate 8 is moved with respect to the first holding plate 7. Thus, the position of the light emitting unit 11 can be adjusted.
[0024]
The first holding plate 7 is formed with two round holes 22a and 22b to which screws (not shown) for fixing the first holding plate 7 to the housing 9 are attached. One round hole 22a has the same diameter as the screw, and the other round hole 22b has a larger diameter than the screw. Further, one adjustment long hole 22c is formed in the first holding plate 7, and a round hole 23 is formed in the housing 9 at a position overlapping the adjustment long hole 22c.
Then, by rotating an eccentric pin (not shown) having the tip portion fitted in the round hole 23 and the eccentric portion fitted in the adjustment long hole 22c, the screw inserted into the round hole 22a is centered. The position of the light emitting unit 11 can be adjusted by rotating the first holding plate 7 to adjust the position.
[0025]
The CCD 15 is fixed to the circuit board 17, and the circuit board 17 is fixed to the housing 9 with screws 24. Two long holes for adjustment 25a and 25b are formed in the circuit board 17, and round holes 26a and 26b are formed in the housing 9 at positions overlapping these long holes for adjustment 25a and 25b. Then, by rotating an eccentric pin (not shown) in which the tip portion is fitted in the round holes 26a and 26b and the eccentric portion is fitted in the adjustment long holes 25a and 25b, the circuit board 17 is moved to the housing 9. The position of the CCD 15 can be adjusted.
[0026]
In such a configuration, the laser light emitted from the light emitting unit 11 is diffused by the diffusion lens 12, and the diffused laser light passes through the half mirror 13 and the glass plate 19 and travels toward the reflecting unit 3, After being reflected by the reflecting section 3, the light travels on the same optical path and returns to the optical unit 2 side. Then, the laser light returns to the optical unit 2 side, and the laser beam that is transmitted through the glass plate 19 and reflected by the half mirror 13 to the CCD 15 side is detected by the CCD 15.
[0027]
In such a state, when a certain position on the panel surface 1a is touched with a finger or the like, the laser light passing through the position is blocked by the finger and received by each CCD 15 of the two optical units 2 respectively. The part which does not occur occurs. The coordinates of the part touched with a finger or the like are detected by calculating by the calculation unit 4 (calculating based on the principle of triangulation) from the detection result of the CCD 15 that has detected the position.
[0028]
Here, since the glass plate 19 is provided at the entrance / exit 18 of the optical unit 2, entry of foreign matter from the entrance / exit 18 into the optical unit 2, such as dust, dust, a finger of a touch panel user, a rod-like member, etc. Intrusion is prevented. For this reason, dust, dust, fingerprints and the like are prevented from adhering to the light emitting unit 11, the CCD 15, and other optical components such as the diffusing lens 12, the half mirror 13, the reading lens 14, etc. The positional deviation of the optical component due to hitting is prevented. As a result, a decrease in light emission efficiency and a decrease in light receiving performance are prevented, and the accuracy of coordinate detection is increased.
[0029]
In addition, since the glass plate 19 has high mechanical strength and high flatness, the laser light that has passed through the glass plate 19 is difficult to diffuse and maintains straightness, so that the light receiving accuracy at the CCD 15 is increased, and coordinate errors occur. Detection is prevented.
[0030]
Further, the glass plate 19 is disposed at an angle of 6 ° with respect to the direction perpendicular to the panel surface 1a. For this reason, even if the laser light that passes through the glass plate 19 and travels toward the reflecting portion 3 is reflected by the glass plate 19, the reflected light is reflected in a direction not received by the CCD 15. The erroneous detection of coordinates caused by the detected laser beam being detected by the CCD 15 is prevented.
[0031]
Next, a second embodiment of the present invention will be described with reference to FIG. The difference between the present embodiment and the first embodiment is that a touch panel 1 and an optical unit 2 are provided as a protective member, in which a glass plate 19a subjected to a shading process is provided instead of the glass plate 19. Since these structures are the same, description will be made with reference to FIGS. 1 to 3 (the same applies hereinafter).
[0032]
The amount of light incident on the CCD 15 has a normal distribution that greatly depends on the illuminance distribution of the irradiation light from the light emitting unit 11 via the diffusion lens 12 and decreases as the center increases and the angle increases. The output of the CCD 15 is large because the center is saturated and is extremely small at both ends with a large angle. Therefore, in order to improve the accuracy of coordinate detection, the amount of light at the center is reduced to the peripheral output level, and uniform output is achieved. It is necessary to perform shading processing so that
[0033]
This shading process is performed by silk-printing a pair of opposing crescents on the surface of the glass plate 19a. By the shading process by silk printing, the region of the glass plate 19a through which the laser light is transmitted is narrow at the center and becomes wider toward both ends, and the light transmission amount is substantially uniform over the entire surface of the glass plate 19a. Further, this silk printing is applied to the surface of the glass plate 19a facing the half mirror 13 in order to prevent peeling off during cleaning or the like. Furthermore, the surface of the glass plate 19a has been subjected to a matte treatment to reduce reflected light.
[0034]
In such a configuration, since the glass plate 19a is subjected to a shading process by silk printing, the amount of laser light transmitted through the glass plate 19a is substantially uniform over the entire surface of the glass plate 19a. For this reason, the amount of light received by the CCD 15 is substantially the same over the entire area of the CCD 15, and the coordinate detection accuracy at the peripheral edge of the panel surface 1a is increased.
[0035]
The shading process is not limited to silk printing, and other methods may be used. For example, a pair of crescent-shaped sheet metals facing the glass plate 19 described in the first embodiment may be attached.
[0036]
Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, the glass plates 19 and 19a described in the first and second embodiments have optical characteristics as shown in the graph of FIG. This optical characteristic transmits light in the wavelength region (545 nm) of the laser light emitted from the light emitting unit 11 and suppresses transmission of light in other wavelength regions.
[0037]
In such a configuration, by using the glass plates 19 and 19a having such optical characteristics, even if disturbance light enters the entrance / exit 18 of the optical unit 2, the disturbance light is transmitted to the glass plates 19 and 19a. Is suppressed, erroneous detection of ambient light by the CCD 15 is prevented, and the coordinate detection accuracy is increased.
[0038]
【The invention's effect】
According to the coordinate detection apparatus for the touch panel of the first aspect of the invention, since the protective member is provided at the entrance / exit of the optical unit through which the light emitted from the light emitting unit and the light reflected by the reflecting unit enter / exit, the entrance / exit Intrusion of foreign matter from the inside of the optical unit, for example, entry of dust, dirt, user fingers, etc., can be prevented, and foreign matter that has entered the optical unit can enter the light emitting part, the light receiving part and other optical components. It is possible to prevent displacement of the optical component due to adhesion or contact with foreign matter, to prevent a decrease in light emission efficiency and a decrease in light receiving performance, and to improve the accuracy of coordinate detection.
According to the coordinate detection apparatus for a touch panel of the first aspect of the invention, since the protective member is subjected to a shading process in which the light transmission amount is substantially uniform over the entire surface, the amount of light received by the light receiving unit is It can be made uniform throughout the entire area, and the detection accuracy of the coordinates of the peripheral edge of the panel surface can be increased.
[0039]
According to the coordinate detection apparatus for a touch panel according to the second aspect of the present invention, when the light emitted from the light emitting portion passes through the protective member, a part of the light is reflected by the protective member, but the reflected light is Since the light is reflected in the direction not received by the light receiving unit, it is possible to prevent erroneous detection of coordinates due to the light reflected by the protection member being received by the light receiving unit.
[0040]
According to the coordinate detection apparatus for a touch panel according to the third aspect of the present invention, since the protective member is formed transparent, the protective member has a transmittance of light emitted from the light emitting portion and light reflected by the reflective portion. This increases the accuracy of coordinate detection.
[0041]
According to the coordinate detection apparatus for the touch panel of the invention described in claim 4, since the protective member is made of glass, the glass has high mechanical strength and high flatness, and light transmitted through the glass is difficult to diffuse. Since the straightness is maintained, the light receiving accuracy at the light receiving unit is increased, and erroneous detection of coordinates can be prevented.
[0043]
According to the coordinate detection apparatus for a touch panel of the invention described in claim 5 , the protective member has an optical characteristic that transmits light in a wavelength region of light emitted from the light emitting unit and suppresses transmission of light in other wavelength regions. Therefore, even if disturbing light enters toward the entrance / exit of the optical unit, the disturbing light is prevented from passing through the protective member, so that it is possible to prevent erroneous detection of disturbing light at the light receiving unit and to detect coordinates. The accuracy can be increased.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a basic configuration of a first embodiment of the present invention.
FIG. 2 is a longitudinal side view showing an internal structure of the optical unit.
FIG. 3 is a bottom view showing the internal structure of the optical unit.
FIG. 4 is a front view showing a glass plate used in the second embodiment of the present invention.
FIG. 5 is a graph showing optical characteristics of a glass plate used in the third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Touch panel 1a Panel surface 2 Optical unit 3 Reflection part 11 Light emission part 15 Light reception part 18 Entrance / exit 19, 19a Protection member

Claims (7)

A plurality of optical units having a light emitting part and a light receiving part arranged at different positions on the outer peripheral edge of the touch panel, and light emitted from the light emitting part arranged on the outer peripheral edge of the touch panel in the emission direction reflecting and a reflective portion of the recursive, while receiving the light reflected by the reflection portion by the light receiving portion, touched on the panel surface of the touch panel by detecting the received light was prevented position In the touch panel coordinate detection device for detecting coordinates indicating the position,
A protective member is provided that transmits light to the entrance / exit portion of the optical unit through which light emitted from the light emitting unit and light reflected by the reflecting unit enter and exit, and prevents entry of foreign matter .
The touch panel coordinate detection device according to claim 1, wherein the protective member is subjected to a shading process in which a light transmission amount is substantially uniform over the entire surface . The protective member, and wherein the light when passing through the protective member are arranged inclined at a predetermined angle in the direction of the light reflected by the protective member is reflected in a direction not received by the light receiving portion The coordinate detection apparatus for a touch panel according to claim 1.   The touch panel coordinate detection apparatus according to claim 1, wherein the protection member is transparent.   4. The touch panel coordinate detection apparatus according to claim 1, wherein the protective member is made of glass.   The said protective member has the optical characteristic which permeate | transmits the light of the wavelength range of the light radiate | emitted from the said light emission part, and suppresses transmission of the light of another wavelength range, The said 1, 2, 3 or 4. The touch panel coordinate detection apparatus according to 4. The coordinate detection apparatus according to claim 1, wherein the optical unit includes a diffusing lens that diffuses light emitted from the light emitting unit. The coordinate detection apparatus according to claim 6, wherein the protective member is subjected to a shading process so that the amount of light diffused by the diffusion lens is uniform over the entire surface.

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