JP2000284896A - Optical scanning touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a touch panel which is excellent in light-receiving sensitivity, requires no precision and is high in safety by hourly measuring the light shielding position of light from a light emitting device consisting of a fluorescent tube from a reference point. SOLUTION: By rotate-scanning the scan mirror 22a of a first channel, light outputted from a fluorescent tube 92 is received by a reflection mirror 93a and the reflected light is received by a light receiving element 17a. This operation is similar in a second channel. Since an object 24 is at a light-shielded position without a signal, the coordinates of this light-shielded position are calculated by the principle of trigonometrical survey. At a scanning angle θ1 on the side of a first channel and a scanning angle θ2 on the side of a second channel, light receiving energy appears in a light receiving element 17 in the effective period of a mirror 22a and since light is interrupted when an object 24 exists, the interruption time is measured. A touch panel MPU calculates the coordinates of the position on a coordinate surface instructed by the object 24 based on an obtained angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device in which a light emitting device is arranged on three sides of a rectangular display screen, and a scanning unit including a rotating mirror and a light receiving unit is arranged on both ends of the other side. The present invention relates to an optical scanning type touch panel in which the operation position of a screen is identified by measuring the time of light shielding.

[0002]

2. Description of the Related Art Generally, an optical scanning type touch panel is shown in FIG.
As shown in the figure, a rectangular substrate 1 formed by forming an optical filter on the lower surface of a protective glass on a rectangular display screen portion 38
0, and the optical scanning units 11a and 11b are arranged so as to face both corners of one side surface thereof.
An elongated frame 12 is fixed to three sides of the optical scanning units 11a and 11b except for the side on which the optical scanning units 11a and 11b are mounted, and a retroreflector 13 is attached to the inner surface of the frame 12. The retroreflector 13 is formed in a tape shape, for example, and is adhered to the inner surface of the frame 12.

The optical scanning unit 11a (and the optical scanning unit 11b) is, as shown in FIG.
The fixing portion (not shown) is fixed to the substrate 10, and the unit main body 14 is mounted on the fixing portion and is attached so that the angle can be adjusted. A light emitting element (for example, a laser diode) 16 such as a semiconductor laser device and a light receiving element 17 are housed in the unit main body 14, and an upper surface thereof is provided.
Laser light 18 as scanning light output from light emitting element 16
A refracting prism 19 for refracting light (hereinafter simply referred to as light 18), a prism 21 having a half mirror 20 for transmitting the refracted light 18, and a scan mirror 22 are provided. , And rotatably provided by a pulse motor 23.

The light 18 output from the light emitting element 16 is
Is refracted by the refraction prism 19, passes through the half mirror 20 and the prism 21, is reflected by the scan mirror 22, and irradiates the retroreflector 13. In this retroreflector 13,
The reflected light is reflected by the scan mirror 22 on the substantially same optical path as the incident light, is reflected and refracted by the half mirror 20 of the prism 21, and is received by the light receiving element 17. The light 18 is scanned by the angle θ (for example, about 90 °) by the rotation of the scan mirror 22 by the pulse motor 23. If there is an object (for example, a finger or a pen) 24 in this optical scanning range, the light 18 is blocked by the object 24, and the angle θ of the object 24 is detected based on the received light energy of the light receiving element 17. You.

In FIG. 9, the optical scanning units 11a, 1a
Assuming that the angles of the object 24 detected in the respective scans 1b are θ1 and θ2, the coordinates (Px, Py) of the position P on the coordinate plane (substrate 10) specified by the object 24 are based on the principle of triangulation. Required by Assuming that the length from one optical scanning unit 11a to the other optical scanning unit 11b on the substrate 10 is L, Py = Px · tan θ1 (1) Py = (L−Px) · tan θ2 (2) Px = {tan θ2 / (tan θ1 + tan θ2)} · L (3) Py = {tan θ1 · tan θ2 / (tan θ1 + tan θ2)} · L (4) based on the equations (1) and (2). Is required.

[0006]

The light emitting device using the light emitting element (for example, laser diode) 16 such as a semiconductor laser device as described above has the following problems. (1) In order to obtain an excellent S / N ratio,
A beam shaping lens that suppresses the spread of the laser light is required, and the adjustment is time-consuming. (2) In the case of using a laser beam, a tape-shaped retroreflector 13 is adhered to an inner surface of a frame 12 provided on three sides of a display screen portion, and this tape-shaped retroreflector is used. 13 is required to have a structure and accuracy for accurately irradiating the laser beam. (3) In the case where a laser beam is used, when an abnormality occurs, there is a danger that a human body, particularly eyes, may be dangerous.

The present invention provides a light-scanning touch panel that has excellent light-receiving sensitivity, does not require high accuracy, and has high safety, in which light-emitting devices other than laser light are arranged on three sides of a rectangular display screen. The purpose is to do so.

[0008]

According to the present invention, there is provided a light emitting device comprising a straight fluorescent tube arranged on three sides of a rectangular display screen, and a light emitting device arranged at both ends of another side of the display screen. A scanning unit including a scan mirror and a light receiving unit, wherein a light shielding position of light from the light emitting device is measured from a reference point to identify an operation position of the display screen unit. It is an optical scanning type touch panel.

In the above configuration, by rotating and scanning the scan mirror 22a of the first channel,
The light 18 output from the fluorescent tube 92 is received by the reflecting mirror 93a, and the reflected light 18 is received by the light receiving element 17a.
This operation is the same in the second channel. Since the position of the object 24 is a light-shielded position where there is no signal, the coordinates of the light-shielded position are calculated based on the principle of triangulation. Regarding the scan angle θ1 on the first channel side and the scan angle θ2 on the second channel, light reception energy appears in the light receiving element 17 during the valid period of the scan mirror 22a. Since 18 is cut off, the time t is measured and obtained. The touch panel MPU 70 calculates the coordinates (Xp, Yp) of the position on the coordinate plane designated by the object 24 by performing a calculation by applying the obtained angles θ1 and θ2 to the equation, and outputs a corresponding signal to the display device. 72.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical scanning type touch panel according to the present invention will be described with reference to the drawings. In FIG. 1, 3
Reference numeral 8 denotes a rectangular display screen section. On this display screen section 38, a rectangular substrate 10 having an optical filter formed on the lower surface of a protective glass is provided, and on three sides, a light emitting device is provided. An elongated straight fluorescent tube 92 is arranged one by one. This fluorescent tube 92 may be visible light or invisible light.

A first-channel optical scanning unit 11a and a second-channel optical scanning unit 11b are arranged facing both corners of another side surface of the protection plate 10. These optical scanning units 11a (and the optical scanning unit 11)
b) is different from FIG. 7 in that the light emitting element 16 and the refraction prism 1
9, the scan mirror 22a (22b),
A pulse motor 23a (23b) for rotating the scan mirror 22a (22b) is provided.

Then, the light 18 from the fluorescent tube 92 is reflected and refracted by the reflecting mirror 93a (reflecting mirror 93b), and the light is received by the light receiving element 17a.
The light is received at (17b). The pulse motor 23a (23
By the rotation of the scan mirror 22a (22b) according to b), scanning is performed by the light receiving angle θ (for example, about 90 °). If there is an object (for example, a finger or a pen) 24 in the light scanning range, the light 18 is blocked by the object 24,
The angle θ of the object 24 is detected based on the light receiving energy of the light receiving element 17a (light receiving element 17b).

Optical scanning unit 1 for first and second channels
1a and 11b and their driving circuits will be described with reference to FIG. The PLL circuit 81 in FIG. 3 will be described later. The first and second channel optical scanning units 11
a and 11b are connected to a touch panel MPU 70, and the touch panel MPU 70 is further connected to a display device 72.

Since the first and second channel optical scanning units 11a and 11b have the same configuration, only the first channel optical scanning unit 11a will be described in detail. The scan mirror 22a is a pulse motor 2
3a, and the pulse motor 23a is connected to a motor driver 51a.

The light receiving element 17a has a current / voltage conversion circuit 52a for converting a current corresponding to the received light energy into a voltage, an A / D (analog / digital) conversion circuit 5
3a and the counter 56a are sequentially connected,
A measurement oscillator 55 that outputs a measurement clock is connected. The measuring oscillator 55 is connected to the optical scanning unit 11.
a and 11b.

The touch panel MPU (microprocessor unit) 70 includes a ROM (read only memory), a RAM (random access memory), a counter and a register, and the one optical scanning unit 11a
The scanning angle θ1 of the object 24 is calculated based on the object detection signal of the count signal of the measurement counter 56a. Further, the touch panel MPU 70 calculates the scanning angle θ2 of the object 24 based on the count signal of the counter 56b based on the received light energy of the light receiving element 17b of the other optical scanning unit 11b. Further, the obtained angles θ1, θ2
Is applied to the equations (3) and (4) to calculate the coordinates (Px, Py) of the position P on the coordinate plane (substrate 10) specified by the object 24, and to obtain a corresponding signal (for example, coordinates Display signal) to the display device 72.

Next, the operation of detecting the coordinate position on the substrate 10 indicated by the object 24 will be described. In the first channel, the scan mirror 22 is driven by the pulse motor 23a.
By rotating and scanning a, the light 18 output from the fluorescent tube 92 is received by the reflecting mirror 93a. The light 18 received and reflected by the reflecting mirror 93a is received by the light receiving element 17a.
This operation is the same in the optical scanning unit 11b of the second channel. Since the position of the object 24 is a light-shielded position where there is no signal, the coordinates (Xp, Yp) of the light-shielded position are calculated based on the principle of triangulation. As described with reference to FIG. 9, this corresponds to the intersection point P when the scanning angle of the object 24 viewed from the first channel side is θ1 and the scanning angle of the object 24 viewed from the second channel side is θ2. Xp = {tan θ2 / (tan θ1 + tan θ2)} · L (5) Yp = {tan θ1 · tan θ2 / (tan θ1 + tan θ2)} · L (6)

How to determine these angles θ1 and θ2 will be described in more detail. In FIG. 2, the scan mirror 22a
During a certain period (for example, about 90 °) of one cycle (for example, about 180 °), received light energy appears in the light receiving element 17a (17b), but an object (for example, a finger or a pen) is within the scanning range. With the presence of the light 24, the light 18 output from the fluorescent tube 92 is blocked by the object 24, and the light receiving energy of the light receiving element 17a (17b) is partially lost. Therefore, the time t from the start point of light reception to the loss of received light energy is measured and calculated by the following equation. Since k = π / T, the angle θ of the object 24 is obtained by the following equation: θ = k × t (7) Here, k: angle per unit measurement time T: maximum number of measurement pulses during one cycle t: time measurement value

Next, the operation of the circuit diagram shown in FIG. 3 will be described. Currents corresponding to the received light energies of the light receiving elements 17a and 17b of the first and second channels are converted into voltages by current / voltage conversion circuits 52a and 52b, respectively, and converted into digital signals by A / D conversion circuits 53a and 53b. A pulse corresponding to the time t from the start of light reception at the scan mirrors 22a and 22b to the loss of light reception energy is output. Further, the measuring clock in one scanning cycle is counted by the counters 56a and 56b. These count signals are output to the touch panel MPU 70.

The touch panel MPU 70 calculates the scanning angle θ1 of the first channel of the object 24 by the above equation (7) based on the count signal of the counter 56a in the optical scanning unit 11a. Similarly, the scanning angle θ2 of the second channel is calculated in the optical scanning unit 11b. Then, the touch panel MPU 70 determines the angle θ
1, θ2 is applied to equations (5) and (6), and the coordinates (Xp, Y) of the position on the coordinate plane designated by the object 24 are calculated.
p), and outputs a corresponding signal to the display device 72.

The two scan mirrors 22a and 22b are
Controlled by a PLL circuit so that the scanning angles can be synchronized, the two fluorescent tubes 92 above and below the display screen section 38 and the other one are alternately lit, and only the necessary portions are lit according to the scanning angle. So that power consumption is suppressed.

In the above embodiment, in order to measure the scanning angle θ, as shown in FIG. 2, the operation position is set based on the time t from the rise of the pulse at the start of scanning to the fall of the object 24. The operation position has an operation width as shown in FIG. 1 when the operation is performed with a finger, so that there is a problem in the case where accuracy is required. Therefore, as shown in FIG. 2, the time width from the fall by the object 24 to the rise by the object 24 is detected,
The operation time may be calculated by the touch panel MPU 70 so as to obtain the operation position by adding the time width t0 of the half point to the time t.

Next, an example in which a PLL circuit 81 is added in FIG. 3 will be described in detail. The PLL circuit 81 controls the scan angles of the two scan mirrors 22a and 22b so as to be synchronized with each other, and as shown in FIGS. 5A and 5B, the two upper and lower fluorescent lights on the display screen section 38. Tubes 92u, 92
The control is performed such that only a necessary portion is turned on depending on the scanning angle, such as turning on v and the other one 92w alternately, so as to suppress power consumption. Specifically, each of the pulse motors 23a and 23b has a Hall element 9 respectively.
1a and 91b are incorporated, and scan mirrors 22a and
The Hall elements 91a and 91 are in phase with the angle of 2b.
4 is output as mirror angle information as shown in FIG. 4 from the connection point between 1b and the resistors 90a and 90b. Each Hall element 9
Outputs of 1a and 91b are 、 divider circuits 82a and 82b
Are divided by 1/2 to obtain signals with a duty ratio of 50% as shown in FIG.
Enter 3 At this time, the pulse motor 23b of CH2
The phase with the pulse motor 23a on the CH1 side is detected with reference to the side.

If the rising portion in FIG. 4 of the 1/2 divider circuit 82a of CH1 is in phase, as in the rising portion (t1) of FIG. 4 in the 1/2 divider circuit 82b of CH2. As shown in FIG. 4, neither the advance signal nor the delay signal is output from the phase comparator 83, and the outputs (wired OR) of the three-state buffers 84 and 85 remain high impedance as shown in FIG. , The previous state is stored in the capacitor 89 component of the LPF (low pass filter) 86, and the VCO to the pulse motor 23a of CH1 is stored.
The voltage control by the (voltage controlled oscillation circuit) 87 maintains the previous state as shown in FIG.

Next, as compared with the rising portion (at time t2) of FIG. 4 in the 分 frequency divider 82b of CH2,
When the phase of the rising portion of FIG. 4 in the 1/2 frequency dividing circuit 82a is advanced, "H" of the 1/2 frequency dividing circuit 82a of CH1 and "L" of the 1/2 frequency dividing circuit 82b of CH2. Under the condition (1), the phase comparator 83 outputs a lead signal as shown in FIG. This signal turns on the 3-state buffer 84 whose input is fixed at L, as shown in FIG.
The "L" signal is output, and the voltage control by the VCO (voltage controlled oscillation circuit) 87 to the pulse motor 23a of CH1 is controlled to be low as shown in FIG. 4, so that the pulse motor 23a of CH1 outputs the pulse of CH2. The rotation is controlled to be delayed by the motor 23b.

On the contrary, as compared with the rising portion (at time t3) of FIG.
If the phase of the rising portion of FIG. 4 in the 1/2 frequency divider 82a is delayed, the 1/2 frequency divider 82a of CH1 is delayed.
Under the condition of “L” of “1” and “H” of the ２ frequency divider 82b of CH2, the phase comparator 83 outputs a delay signal as shown in FIG. By this signal, the input is fixed to H
When the state buffer 85 turns on, as shown in FIG.
The "H" signal is output, and the voltage control of the pulse motor 23a of CH1 by the VCO (voltage controlled oscillation circuit) 87 is controlled to be high as shown in FIG. 4, so that the pulse motor 23a of CH1 outputs the pulse of CH2. The rotation is controlled by the motor 23b. By repeating this, the pulse motors 23a and 23b of CH1 and CH2 are
Are synchronized, and the scanning angles of the scan mirrors 22a and 22b are synchronized.

As described above, when the scan angles of the scan mirrors 22a and 22b of CH1 and CH2 are synchronized, as shown in FIG. 5A, the scan direction is reversed (the solid line direction and the dotted line direction). ), The scan mirror 22a of CH1 moves t1 and t1 as shown in FIG.
2 is a section of the fluorescent tube 92w, and between t2 and t3 is the fluorescent tube 92w.
v, and scan mirror 22 of CH2
b is the fluorescent tube 9 between t1 and t2 as shown in FIG.
The section 2w is scanned between t2 and t3 with the section of the fluorescent tube 92u. Therefore, as shown in FIG. 5B, the fluorescent tube 92w is turned on during the period between t1 and t2, and is turned off at other times.
As shown in FIG. 5B, the power consumption of u and 92v can be reduced by controlling the lighting between t2 and t3 and turning off the others.

In the above embodiment, the light emitting device is a case where three straight tubular fluorescent tubes 92u, 92v and 92w are used. However, the present invention is not limited to this. As shown in FIG.
Multiple point light sources (e.g., _{LED) 92u 1 ..., 92v 1} ...,
Place 92w ₁ ... the around the 3-way, CH1, CH2 of the pulse motor 23a, to synchronize the rotational speed of 23b, CH
In one scan mirror 22a, 92w ₁ , 92v ₁ .
And the scan mirror 22b of CH2
If the switching on and off is sequentially controlled so as to scan n ..., 92un ..., the power consumption can be further greatly reduced.

[0029]

According to the first aspect of the present invention, the light emitting devices arranged on three sides of the display screen section, and the scanning section comprising the scanning mirrors and the light receiving sections arranged at both ends of the other one side of the display screen section. Therefore, without using a light emitting element such as a semiconductor laser device, the light shielding position of the light from the light emitting device can be measured from the reference point, and the operation position of the display screen can be identified.

According to the second aspect of the present invention, since a straight fluorescent tube is used as the light emitting device, a lens for beam shaping is not required and its adjustment is not required as compared with a device using laser light. . In addition, those using laser light require a retroreflector, and are required to have a structure and accuracy for accurately irradiating the retroreflector with laser light.
The present invention does not have such a problem. Further, a laser beam using a laser beam may pose a danger to the human body, especially to the eyes when an abnormality occurs, but according to the present invention, it is extremely safe.

According to the third aspect of the present invention, the pulse motor for controlling the rotation of each of the two scan mirrors is connected to a PLL circuit for synchronizing the scan angles with each other. The two fluorescent tubes on the side and the other one
As one fluorescent tube on the side was turned on alternately,
Power consumption can be reduced.

According to the invention described in claim 4, the PLL circuit is incorporated in two pulse motors, and outputs a mirror element as mirror angle information of two scan mirrors.
A frequency dividing circuit that divides the output of each Hall element, a phase comparator that uses the output of one motor as a reference, and compares the output of the other motor as an input, and a lead or delay output of the phase comparator. An L or H fixed 3-state buffer;
LPF for storing the output state of the three-state buffer
And a voltage-controlled oscillation circuit that performs voltage control for controlling the rotation of the two pulse motors based on the L or H signal, so that the pulse motor controls the respective rotations of the two scan mirrors. Can be accurately synchronized with each other.

According to the fifth aspect of the present invention, the operation width of the display screen is detected, and the time width of the middle point is added to the time measurement value from the reference point to identify the operation position. Even if the operation width is wide to some extent, the operation position can be more reliably identified.

According to the sixth aspect of the present invention, there is provided a light-emitting device comprising a plurality of point light sources which can be controlled to be turned on and off independently and which are arranged on three sides of a rectangular display screen, A scanning unit including a scanning mirror and a light receiving unit disposed at both ends of one side of the side, and measuring a time from a reference point to a light blocking position of light from a number of point light sources as the light emitting device, and a display screen unit. Since the operation position is identified, power consumption can be greatly reduced.

According to the seventh aspect of the present invention, the pulse motor for controlling the rotation of each of the two scan mirrors is connected to the PLL circuit for synchronizing the scan angles with each other. A plurality of point light sources that can be independently turned on and off can be controlled to be turned on and off by one or more, so that the scanning angles of the two scan mirrors can be accurately synchronized. it can.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an optical scanning type touch panel according to the present invention.

FIG. 2 is an output waveform diagram of the optical scanning type touch panel according to the present invention.

FIG. 3 is a block diagram of an electric circuit for controlling the optical scanning type touch panel according to the present invention.

FIG. 4 is an operation waveform diagram of a PLL circuit 81 in FIG. 3;

5A and 5B are diagrams for explaining control of turning on and off three fluorescent tubes 92u, 92v, and 92w. FIG. 5A is a plan view of a display screen unit 38, and FIG. 2
The scanning time of 2a, 22b and the three fluorescent tubes 92u, 92
It is explanatory drawing of lighting and extinguishing of v, 92w.

FIG. 6 is an explanatory plan view of a display screen unit 38 when the light emitting device is a point light source (LED).

FIG. 7 is a plan view of a general optical scanning type touch panel.

FIG. 8 is a front view of a general optical scanning unit.

FIG. 9 is an explanatory diagram showing the principle of triangulation for coordinate detection.

[Explanation of symbols]

Reference numeral 10: protection plate, 11a: first channel optical scanning unit, 11b: second channel optical scanning unit, 12:
Frame, 13: retroreflector, 14: unit body,
16 light emitting element, 17 light receiving element, 18 light, 19 refraction prism, 20 half mirror, 21 prism, 2
2 ... scan mirror, 23 ... pulse motor, 24 ... object, 25 ... unit support plate, 38 ... display screen part, 51 ...
Motor driver, 52: current / voltage conversion circuit, 53: A
/ D conversion circuit, 55: measurement oscillator, 56: counter,
70: Touch panel MPU, 72: Display device, 81: P
LL circuit, 82 ... 1/2 frequency divider circuit, 83 ... phase comparator,
84, 85 ... 3-state buffer, 86 ... LPF, 87
... VCO, 88, resistor, 89, capacitor, 90, resistor, 91, Hall element, 92, fluorescent tube, 93, reflector.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B068 AA22 BB20 BC04 BE03 BE06 BE12 CC12 CC17 CC18 5B087 CC25 CC26 CC34 DD03 DD10 DJ01

Claims (7)

[Claims] 1. A light-emitting device disposed on three sides of a display screen unit, and a scanning unit including a scan mirror and a light-receiving unit disposed on both ends of another side of the display screen unit, An optical scanning touch panel, wherein an operation position of a display screen portion is identified by measuring time from a reference point to a light shielding position. 2. A light emitting device comprising a straight fluorescent tube disposed on three sides of a rectangular display screen, and another one of the display screens.
A scanning unit including a scanning mirror and a light receiving unit disposed at both ends of the side, and measuring a time from a reference point to a light shielding position of light from a straight fluorescent tube as the light emitting device to measure a time on a display screen unit. An optical scanning type touch panel, wherein an operation position is identified. 3. A pulse motor for controlling the rotation of each of two scan mirrors is coupled to a PLL circuit for synchronizing the scan angles with each other. 3. An optical scanning type touch panel according to claim 2, wherein one fluorescent tube on another side is alternately turned on. 4. A PLL circuit is incorporated in two pulse motors and outputs a Hall element that outputs as mirror angle information of two scan mirrors, a frequency dividing circuit that divides the output of each Hall element, and one frequency dividing circuit. A phase comparator that compares the other frequency-divided output with the output as an input, an L- or H-fixed three-state buffer whose one is selected based on the advance or delay output of the phase comparator, 4. An LPF for storing an output state of a state buffer, and a voltage control oscillation circuit for performing voltage control for controlling rotation of the two pulse motors based on the L or H signal. Optical scanning touch panel. 5. An operation position of the display screen portion is detected, and a time width of a middle point thereof is added to a time measurement value from a reference point to identify an operation position. 2
The optical scanning type touch panel according to the above. 6. A light-emitting device comprising a plurality of point light sources independently controllable to be turned on and off arranged on three sides of a rectangular display screen portion, and disposed at both ends of another side of the display screen portion. A scanning unit including a scan mirror and a light receiving unit, and a light blocking position of light from a number of point light sources as the light emitting device is measured from a reference point to identify an operation position of the display screen unit. An optical scanning touch panel, characterized in that: 7. A pulse motor for controlling the rotation of each of two scan mirrors is coupled to a PLL circuit for synchronizing the scan angles with each other, and is independently lit on three sides of a display screen. A large number of controllable point light sources
7. The light-scanning touch panel according to claim 6, wherein switching between lighting and extinguishing is performed by a plurality of pieces.