JP2001264011A - Optical touch panel device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To identify the rotational positions of rotating mirrors each scanning by reflecting a laser beam, while rotating. SOLUTION: The rotating mirrors 2 are provided in two positions on one side of a touch panel, Reflection surfaces 1 to 4 of each mirror reflect a laser beam from a light source and reflect a return beam, reflected by a retroreflector on the other side of the touch panel, The return beam is detected by a reflection beam detecting part, The coordinates of a touch are determined from an angle, at which two return beams is broken. Magnetic bodies 31 to 34 of different widths are mounted on the upper surface of each mirror at equal angular distances, their magnetism is detected by an identifier detecting part 25, and the reflection surfaces are identified based on signals therefrom, A pulse- generating part 26 generates pulses, based on the signals from the detecting part 25, the phase of the pulses is adjusted by a phase adjustment part 27, The pulses are used as reference signals for starting the respective reflection surfaces scanning and also as references for detecting the coordinates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical touch panel device, and more particularly to an optical touch panel device which identifies a reflection surface of a rotating mirror that scans by reflecting a laser beam from a light source, and facilitates maintenance when the rotating mirror becomes dirty. .

[0002]

2. Description of the Related Art In an optical touch panel device, for example,
As shown in FIG. 7, rotating mirrors 73 and 74 each having a reflecting surface formed on each surface of the quadrangular prism are rotated on the side of the touch panel 61, and the laser light from the light source 71 and the light source 72 is rotated by the rotating mirror 73.
Scan with reflection at 74 and retroreflector 62 (eg,
On the reflecting surface, three triangular mirrors with a right angle are connected, two sides sandwiching the right angle are in contact with each other, and a triangular pyramid-shaped microblock is formed so that the mirror surface is at a right angle to each other, and the bottom side is connected and arranged. The light is reflected once or three times by the mirror surface according to the incident angle and is reflected and output in the incident direction).
The 75 coordinates x and y are calculated and the position is specified. Angle θ1,
θ2 is obtained by multiplying the rotation angle per unit time of the rotating mirrors 74 and 75 by the time from the reference signal to the break of the reflected light beam, and the coordinates x and y are represented by the coordinates y = L · tan θ2 / (tan θ2 + Tan θ1), and coordinates x = y · tan θ1. The signal processing is performed using a directly reflected light beam emitted from the light source and reflected by the rotating mirror as a reference signal.

[0003]

When dirt adheres to the reflecting surface of the above-mentioned rotating mirror and causes malfunction, the reference signal becomes unclear and it is difficult to determine which reflecting surface is dirty. There was a problem. The present invention mounts an identification body on the upper surface of a rotating mirror, identifies the position of the rotating mirror by detecting the identification body, and further has a reflecting surface identification function on the identification body to facilitate maintenance in the event of malfunction. The purpose is to:

[0004]

In order to achieve the above object, in the optical touch panel device of the present invention, two light sources for emitting laser beams and reflecting surfaces are formed on four sides of a quadrangular prism, and one side of the touch panel is formed. Two rotating mirrors arranged at two locations to reflect and scan laser beams from two light sources, respectively, a retroreflector provided inside the other three sides of the touch panel, and scanning by each of the rotating mirrors The reflected light detector that detects the laser beam reflected by the retroreflector and the signal from the reflected light detector calculates the angle from the scanning start point of the laser beam to the point where the reflected light is interrupted, and detects the coordinates. In the optical touch panel device comprising a coordinate detecting unit, a discriminator for discriminating a rotational position is attached to an upper surface or a bottom surface of each rotating mirror, and the discriminator is provided. An identification object detection unit to be detected, a reference signal generation unit that generates a reference signal for starting scanning of a laser beam based on a signal from the identification object detection unit is provided, and a coordinate detection unit uses the signal from the reference signal generation unit as a reference. It is configured to detect coordinates.

[0005] On the top or bottom of each rotating mirror,
Four magnetic bodies are attached at equal angular intervals as identification bodies, and the magnetism of the magnetic bodies is detected by the identification body detection unit.

[0006] Four magnetic bodies having different widths are attached as discriminators at equal angular intervals, the position of the four magnetic bodies is detected by the discriminator detection unit based on the difference in magnetism, and the reflecting surface of the reflection surface is detected based on the detection signal. Identification may be performed.

[0007] Alternatively, on the two concentric circles on the top or bottom of each rotating mirror, each of the circles is identified as an identification body.
An arc-shaped conductor or magnetic material with a length of 1/4 is attached to each of two specified places, and the identification object detection unit detects conduction with the conductor or detects magnetism by the magnetic material and reflects based on the detection signal. Perform surface identification.

[0008] Then, based on the detection signal from the discriminating object detection section, the reflection surface on which the low-level reflection light is detected by the reflection light detection section is identified.

A reflected light detector has a first resistor connected to one end of a power supply, and a photodiode (hereinafter referred to as PD) having a cathode connected to the other end of the first resistor and an anode connected to ground. The voltage generated in the first resistor is input to a current control unit for controlling the drive current of the laser diode (hereinafter, referred to as LD), and the current of the LD is controlled via the second resistor connected in series. And, the light emission amount is configured to be maintained at a predetermined level, and when the identifier detecting unit detects a reflection surface having a low reflected light level, the resistance value of the first resistor or the second resistor is switched, The drive current of the LD is increased to increase the light emission amount.

Alternatively, there is provided a pulse generator for generating a pulse having a width corresponding to a range in which the amount of return light detected by the reflected light detector is small based on a reference signal from the reference signal generator. An AND circuit for performing an AND operation on a signal from the unit and a reflection surface identification signal based on a signal from the identification object detection unit, and switches the first resistor or the second resistor based on a signal from the AND circuit; You may do so. Alternatively, the pulse generating unit is provided with a waveform shaping unit that shapes the waveform of the return light beam detected by the reflected light beam detection unit, and an MPU that calculates the amount of light per unit area of the return light beam based on a signal from the waveform shaping unit. In this case, a pulse having a width corresponding to a plane in which the light amount of the return light beam calculated by the MPU is equal to or less than a predetermined level may be generated based on a reference signal from the reference signal generation unit.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a block diagram of a main part of an embodiment of an optical touch panel device according to the present invention.
1a and 1b are LDs of a light source for emitting a laser beam,
2a and 2b are rotating mirrors that reflect laser beams from the light sources 1a and 1b, 3 is a motor that rotates the rotating mirrors 2a and 2b,
4 is a motor drive unit, 5 is an oscillation circuit for supplying power for driving the motor, and 6a and 6b are PDs for receiving laser beams.
(Reflected light beam detector), 7 is an A / V converter for converting a current value obtained by receiving light from the PDs 6a and 6b into a voltage value, and 8 is a signal (voltage value) from the A / V converter 7 which is converted into a digital signal. A
A primary reflection light separation unit 9 for separating the primary reflection light beam and extracting a rotation pulse; a counter 10 for counting a signal from the primary reflection light separation unit 9 based on a signal from the oscillator 11; MPU for data processing, 13 is work RAM
Then, these primary reflected light separation unit 9, counter 10, oscillator 1
1. The MPU 12 and the work RAM 13 constitute a coordinate detection unit.

The LDs 1a and 1b (light sources) are arranged on one side of the touch panel, and emit laser beams by pulse driving. This laser beam is scanned by reflection from rotating mirrors 2a and 2b (reflected by a motor drive unit 4 by a power supply from an oscillation circuit 5 using a PLL) having reflection surfaces formed on four sides, and formed on the inner wall of the touch panel. PD6a, 6b (LD1a, 1b
In the vicinity). The current values of the PDs 6a and 6b generated by the light reception are converted into voltage values by an A / V converter 7 and digitally converted by an A / D converter 8, and are primarily reflected by a primary reflected light separator 9 constituting a coordinate detector. Is separated, the rotation pulse is taken out, input to the counter 10, counted using the signal from the oscillator 11, and the reflected light from the retroreflector is determined based on the reference signal for starting the scanning of the rotating mirrors 2a and 2b. The rotation angles of the rotating mirrors 2a and 2b when the touch is interrupted by the touch object are calculated, and the MPU 12 calculates the coordinates of the object touched on the touch panel by using the work RAM 13.

FIG. 2 is a view for explaining an example of a rotating mirror and signal processing. The center O and each of the angles A, B, C and D are connected to the upper surface of the rotating mirror 2 (corresponding to 2a and 2b in FIG. 1). Magnetic bodies 21, 22, 23, and 24 are attached as discriminators at positions (equal angular intervals), and the magnetism from each magnetic body is detected by a discriminator detection unit 25 (magnetic sensor). The rotation of the rotating mirror 2 causes the magnetic substance to be detected by the identification object detection unit 25.
The signal is picked up when the signal passes under, and the signal A is input to a reference signal generation unit composed of a pulse generation unit 26 and a phase adjustment unit 27, and a predetermined pulse is generated by a pulse generation unit 26 (multivibrator or the like) to adjust the phase. The phase is appropriately adjusted by the unit 27, and is used as a reference signal for starting scanning of each reflecting surface of the rotating mirror.

FIG. 3 shows an example in which four magnetic bodies 31, 32, 33, and 34 having different widths are mounted on the upper surface of the rotating mirror 2 as identification bodies in the same manner as in FIG. Based on the signal A detected by the identification object detection unit 25, the pulse generation unit 26 sets a predetermined pulse (B),
The phase adjustment unit 27 adjusts the phase, and uses it as a reference signal for starting scanning of each reflection surface of the rotating mirror 2. The signal a is a rotating mirror 2
Since the width differs depending on the position and the rising position differs, the reflection surfaces 1 to 4 of the rotating mirror 2 can be identified by the processing of the signal A from the identification object detection unit 25, so that this signal and the signal from the reflected light beam detection unit By the above processing, it is possible to identify the reflection surface where the level of the reflected light beam has decreased due to the attachment of dirt or the like, thereby facilitating maintenance.

FIG. 4 shows arc-shaped conductors 41, 42, 43 and 44 each having a length of 1/4 of each circumference as discriminators on two concentric circles on the upper surface of the rotating mirror 2. Two conductors are attached on the circumference, and conduction with the conductors 41 or 42 and the conductors 43 or 44 is detected by the two brushes of the identification object detection unit 45. The detected signal A (and) is decoded into a signal B ((1), (2), (3) and (4)) by a 2-4 decoder 46 and a pulse generator 47 of a reference signal generator. A pulse that falls at the rising edge of the decode signal is generated, and the four pulses are logically ORed to form a signal C. The phase is adjusted by the phase adjusting unit 48 and used as a reference signal for starting scanning of each reflection surface of the rotating mirror 2. . Then, the reflecting surfaces 1 to 4 of the rotating mirror 2 are identified by the processing of the signal b from the 2-4 decoder 46, and the reflecting surface with dirt is specified by processing this signal and the signal from the reflected light beam detector. And maintenance. Note that a magnetic body having the same shape as the conductor is attached to the conductors 41 to 44 in place of the conductor, and two pickups are provided in the discriminating body detection unit 45 to detect the magnetism of the magnetic body on each circumference, and signal I May be taken out.

The light receiving waveform shown in FIG. 5 shows a state in which the light returning to the LD is blocked by the touch object of the touch panel and is lowered (V-shaped part in the figure). This is an example of a case where the reflection surface is larger than the reflection surface. This is determined by processing (calculation) of the signal from the discriminating object detection unit 25 or 45 and the signal from the reflected light beam detection unit. For this compensation, the LD control circuit (1) or (2) shown in FIG.
The monitor signal detected by D (the voltage of the first resistor R1, R2 or R4 generated according to the light receiving current of the PD) is supplied to the current control unit 51.
When the detection level of the reflected light by the PD is low, the second resistor R3, R5 or R6 for limiting the current in series is connected.
Is a circuit that increases the drive current of the LD through the interface to increase the laser beam output. That is, in the LD control circuit (1), when the light receiving level of the PD is low due to insufficient light quantity, the switch S1 of the first resistor (R1 and R2, R1> R2) is switched from the R1 side to the R2 side, and the monitor input is performed. Raise the signal to increase the LD drive current. In the LD control circuit (2), when the light receiving level of the PD is low, the switch S2 of the second resistor (R5 and R6, R6> R5) is switched from the R6 side to the R5 side to increase the LD driving current. , The drive current of the LD is increased.

Alternatively, as shown in FIG. 6, the switch S1 is set to the R1 side in the range A to B where the optical path of the laser beam is long and the light amount of the return beam is insufficient on the reflecting surface 3 (example) having a low reflected light level. Or switch S2 is switched to R5. An LD drive control signal for switching the switches S1 and S2 is generated by a pulse generation unit 63 based on a reference signal (synchronization signal) from the reference signal generation unit.
A pulse having a width corresponding to a range in which the amount of return light (current) detected in D) is smaller than a predetermined level is generated, and a reflection surface identification signal based on a signal from the identification object detection unit 25 or 45 and an AND circuit 64. The signal from the AND circuit 64 is used to calculate the switch S1 of the LD control circuit (1) in FIG.
(2) The switch S2 is switched. In this case, a pulse shaping unit is provided, which includes a waveform shaping unit that shapes the waveform of the return light beam detected by the reflected light beam detection unit, and an MPU that calculates the amount of light per unit area of the return light beam based on a signal from the waveform shaping unit. A pulse having a width corresponding to a surface where the light amount of the return light beam calculated by the MPU is equal to or lower than a predetermined level may be generated based on the reference signal from the reference signal generation unit. Alternatively, a pulse that rises at the fall of the return light beam waveform detected by the reflected light beam detector is generated, this pulse is integrated, and this waveform and the reflection surface identification signal are calculated by the logical product circuit. Good.

[0018]

As described above, according to the optical touch panel device of the present invention, the identification body (magnetic material or conductor) is attached to the rotating mirror, and the position of the rotating mirror is identified by detecting the identification body. In addition, since the reference signal is used as a reference signal for starting the scanning of the laser beam, the problem that the reference signal is unclear due to dirt on the reflection surface and an operation failure occurs as in the conventional device using the reflected light of the rotating mirror as the reference signal is solved. be able to. In addition, since the reflection surface can be identified by detecting the identification object, it is effective for maintaining the dirty reflection surface. Furthermore, when the amount of returning light is small, the driving current of the LD can be increased to increase the output of the laser beam, thereby improving the operation.

[Brief description of the drawings]

FIG. 1 is a main part block diagram of an embodiment of an optical touch panel device according to the present invention.

FIG. 2 is an explanatory diagram of an example of a rotating mirror and signal processing.

FIG. 3 is an explanatory diagram of another example of a rotating mirror and signal processing.

FIG. 4 is an explanatory diagram of another example of a rotating mirror and signal processing.

FIG. 5 is an explanatory diagram of an example of laser beam output compensation.

FIG. 6 is an explanatory diagram of another example of laser beam output compensation.

FIG. 7 is a diagram illustrating an example of a conventional optical touch panel device.

[Description of Signs] 1a, 1b, LD Laser Diode 2a, 2b, 2, 73, 74 Rotating Mirror 3 Motor 4 Motor Driving Unit 5 Oscillator 6a, 6b, PD Photodiode 7 A / V Converter 8 A / D Converter Unit 9 Primary reflected light separation unit 10 Counter 11 Oscillator 12 MPU 13 Work RAM 21 to 24, 31 to 34 Magnetic material 25, 45 Identification object detection unit 26, 47, 63 Pulse generation unit 27, 48 Phase adjustment unit 41 to 44 Conductor 46 2-4 decoder 51 Current controller 61 Touch panel 62 Retroreflector 64 AND circuit 71, 72 Light source and reflected light detector 75 Target object (touch object) R1-R6 Resistor S1, S2 switch

Claims (10)

[Claims] 1. Two light sources for emitting a laser beam;
Reflecting surfaces are formed on the four sides of the quadrangular prism, arranged at two places on one side of the touch panel, two rotating mirrors that respectively reflect and scan laser beams from two light sources, and the other three sides of the touch panel. A retroreflector provided on the inside, a reflected light detector that detects a laser beam scanned by each of the rotating mirrors and reflected by the retroreflector, and a scanning start point of the laser beam based on a signal from the reflected light detector. In an optical touch panel device including a coordinate detection unit that calculates an angle to a point where a reflected light beam is interrupted and detects coordinates, an identification body for identifying a rotation position is attached to an upper surface or a bottom surface of each of the rotating mirrors. An identification object detection unit that detects the identification object, and a reference signal generation unit that generates a reference signal for starting scanning of the laser beam based on a signal from the identification object detection unit. Wherein the signal from the reference signal generator in the reference coordinate detection unit the optical touch panel device which is adapted to detect the coordinates by. 2. The identification body is provided with four magnetic bodies at equal angular intervals on an upper surface or a bottom surface of each of the rotating mirrors, and the magnetic body of the magnetic body is detected by the identification body detection unit. The optical touch panel device as described in the above. 3. Four magnetic bodies having different widths are attached at equal angular intervals to the top or bottom surface of each of the rotating mirrors as the discriminator, and the discriminator detection unit detects four magnetic bodies due to differences in magnetism. 2. The optical touch panel device according to claim 1, wherein the position is detected, and the reflection surface is identified based on the detection signal. 4. An arc-shaped conductor having a length of 1/4 of each circumference is attached to each of two predetermined concentric circles on an upper surface or a bottom surface of each rotating mirror at predetermined two positions, respectively. 2. The method according to claim 1, wherein the identification object detection unit detects conduction with a conductor and identifies a reflection surface based on a detection signal.
The optical touch panel device as described in the above. 5. An arc-shaped magnetic body having a length of 1/4 of each circumference is attached to each of two predetermined concentric circles on an upper surface or a bottom surface of each of the rotating mirrors. 2. The optical touch panel device according to claim 1, wherein the magnetism of the magnetic body is detected by the identification body detection unit, and the reflection surface is identified based on the detection signal. 6. A reflection surface on which a reflected light beam of a low level is detected by said reflected light beam detecting unit based on a detection signal from said discriminating object detecting unit.
The optical touch panel device as described in the above. 7. The reflected light detector includes a first resistor having one end connected to a power supply, and a photodiode having a cathode connected to the other end of the first resistor and an anode connected to the ground. The voltage generated in the resistor is input to a current control unit for controlling the drive current of the laser diode, and the current of the laser diode is controlled via a second resistor connected in series so that the light emission amount is maintained at a predetermined level. 7. The optical system according to claim 6, wherein when a reflection surface having a low reflected light level is identified, the resistance value of the first resistor is switched to increase the drive current of the laser diode to increase the light emission amount. Touch panel device. 8. A reflected light detector, comprising: a first resistor having one end connected to a power supply; and a photodiode having a cathode connected to the other end of the first resistor and an anode connected to ground. The voltage generated in the resistor is input to a current control unit for controlling the drive current of the laser diode, and the current of the laser diode is controlled via a second resistor connected in series so that the light emission amount is maintained at a predetermined level. 7. The optical system according to claim 6, wherein when a reflection surface having a low reflected light level is identified, the resistance value of the second resistor is switched to increase the drive current of the laser diode to increase the light emission amount. Touch panel device. 9. A pulse generator for generating a pulse having a width corresponding to a small range of the amount of return light detected by the reflected light detector based on a reference signal from the reference signal generator, An AND circuit for performing an AND operation on a signal from a pulse generation unit and a reflection surface identification signal based on a signal from the identification object detection unit, and the first resistor or the second resistor based on a signal from the AND circuit; 9. The optical touch panel device according to claim 7, wherein the device is switched. 10. A waveform shaping unit for shaping a waveform of a return light beam detected by the reflected light beam detection unit, and an MPU for calculating an amount of light per unit area of the return light beam based on a signal from the waveform shaping unit, The pulse generator, wherein a pulse having a width corresponding to a surface on which a light amount of a return light beam calculated by an MPU is equal to or lower than a predetermined level is generated based on a reference signal from the reference signal generator. 10. The optical touch panel device according to 9.