KR950009355B1 - Optical positioning measuring device and method - Google Patents

Abstract

The device for detecting coordinates by using an optical method comprises a horizontal light emitting unit and a horizontal light receiving unit; a vertical light emitting unit and a vertical light receiving unit; a light emitting element selecting/driving unit; a light receiving element selecting unit for selecting the light receiving element to selectively detect the light signal of the light receiving element of the light receiving element selecting unit corresponding to the light emitting element driven by the light emitting element selecting/driving unit; a light receiving signal shaping unit for wave-shaping the light signal detected by the light receiving element selecting unit and outputting a light receiving pulse; a counter for calculating the light receiving pulse outputted from the light receiving signal shaping unit and outputting it as object existence/nonexistence sensing information; a CPU for controlling the driving timing of the luminous element selecting/driving unit and light receiving element selecting unit and calculating the touch coordinates of the object by interpreting the count value applied from the counter; and a coordinates transferring unit for supplying the coordinates information obtained from the CPU to a system requiring the information .

Description

Optical coordinate detection device and method

1 is a configuration diagram of an arrangement of optical elements in a conventional coordinate detection apparatus.

2 is a diagram illustrating an example in which an object blocks a part of an optical path in a conventional coordinate detection apparatus.

3 is a block diagram of the coordinate detection apparatus of the present invention.

4 is a detailed circuit diagram of an embodiment of the coordinate detection apparatus of the present invention.

5 is a flowchart of the coordinate detection apparatus of the present invention.

6 is a coordinate detection timing diagram by the apparatus of the present invention.

7 is a signal waveform diagram when no object exists on the light receiving path of the device of the present invention.

8 is a waveform diagram when an object blocks a part of an optical signal on a light receiving path of the device of the present invention.

* Explanation of symbols for main parts of the drawings

1: horizontal light emitting unit 2: vertical light emitting unit

3: horizontal light receiving unit 4: vertical light receiving unit

6 light emitting element selection / driver 7 light receiving element selection unit

8: light receiving signal shaping unit 9: counter

10: CPU 11: coordinate transfer unit

The present invention relates to an optical coordinate detection device and a coordinate detection room for detecting coordinates using a light emitting element and a light receiving element.

In the conventional optical coordinate detecting apparatus, referring to FIG. 1, a pair of light emitting elements 1 and a light receiving element 3 that are horizontally opposed to each other, and a pair of light emitting elements 2 and a light receiving element 4 that are vertically opposed to each other are provided. It is provided at the edge of the screen SCREEN, and the coordinates of the object are detected by analyzing the electric signal detected from the light receiving element whose light is blocked by the object touching the screen.

That is, the light emitting elements 1 and 2 are sequentially driven one by one, and coordinates according to the presence, absence, presence, and absence of the object from the reception of the light receiving elements 3 and 4 facing each other at the driving timing thereof. Perform the (x, y) calculation.

In this case, since sunlight or fluorescent light has a light output level that is several times to several thousand times higher than the light output levels of the light emitting devices 1 and 2, only the optical signals output from the light emitting devices 1 and 2 that are driven. In order to detect, the light emitting elements 1 and 2 are sequentially driven on / off switching at regular intervals, and whether or not an optical signal for detecting a change in the photocurrent flowing through the opposing light receiving elements 3 and 4 is detected. Detects at which point on the x and y coordinates the object is positioned (light-blocked).

The determination of the presence or absence of an object compares the optical signal level detected by the light receiving elements 3 and 4 with a predetermined reference value, and if the comparison value is less than the reference value, an object exists on the optical path to block the optical signal. It is determined that.

Therefore, when the object 5 partially blocks an optical path composed of one light receiving element 3 facing one light emitting element 1 as shown in FIG. 2, the optical signal level detected by the light receiving element 3 is detected. The phenomenon that crosses the above or below range slightly occurs around the reference value, and this phenomenon causes a slight vibration of the object 5, that is, a person blocks a light pen or finger, etc. Since it is used in (5), it becomes further weighted by the inevitable micro-vibration (vibration by a pulse or an individual difference).

Therefore, in this case, the optical signal level detected by the light receiving elements 3 and 4 becomes severely unstable, which adversely affects the calculation of the coordinates, thus causing a problem that the reliability and accuracy in the coordinate detection are degraded. .

In addition, even when an external flash or electrical noise flows in momentarily, malfunctions are caused due to such instability of the received signal, thereby greatly lowering the reliability of the whole.

The present invention blinks a selected light emitting device on a horizontal / vertical orthogonal optical path at a predetermined number of times, and counts the number of optical signal pulses detected by opposing light receiving elements to determine whether an object is present or not through count value analysis. Since the coordinate detection is performed, an optical coordinate detection device and a coordinate detection method for reducing the coordinate detection error and ensuring reliability and precision in the detection operation are provided with reference to the accompanying drawings. The configuration will be described below.

First, referring to FIG. 3, the optical coordinate detection apparatus of the present invention includes a horizontal / vertical light emitting unit (1), (2), and a horizontal / vertical light receiving unit, which are arranged in pairs and are opposed to each other horizontally and vertically. (3), (4), and a light emitting element selection / driver section 6 for selectively performing a predetermined number of sequential blinking operations for each light emitting element of the light emitting elements 1 and 2, and Selected and detected by the light receiving element selection unit 7 and the light receiving element selection unit 7 for selectively detecting the optical signals of the light receiving elements of the light receiving units 3 and 4 corresponding to the light emitting element to be selectively driven. A light receiving signal shaping unit 8 for waveform shaping an optical signal to be output and receiving light receiving pulses, a counter 9 for counting light receiving pulses and outputting them as presence / absence detection information, and the light emitting element selection / driving unit 6 And controlling the driving timing of the light receiving element selector 7 and removing it from the counter 9. Is composed of a CPU 10 for analyzing the count value to determine the existence of an object and calculating the object touch coordinates, and a coordinate transmission unit 11 for supplying the calculated coordinate information to the system.

On the other hand, referring to Figure 4, the horizontal / vertical light emitting unit (1), (2) is composed of light emitting diodes (LD1 to LDy), (LDy + 1 to LDx), the horizontal / vertical light receiving unit (3) ) And (4) are composed of light receiving transistors S1 to Sy and (Sy + 1 to Sx), and the light emitting element selection / driver 6 is a decoder 6A for driving light emitting diodes in group units. And a decoder 6B for selectively driving a specific light emitting diode in the group, and the light receiving element selecting section 7 includes a decoder 7A for selecting the light receiving transistors in group units and a specific in the group. It consists of an analog multiplexer (7B) for selecting a light emitting diode, the light receiving signal shaping section 8 is amplifying section (8A) for amplifying the received signal, and the amplified light receiving signal on the basis of a predetermined threshold value It is composed of a Schmitt trigger circuit section 8B for converting into a signal, the CPU 10 Built-in counter 9, coordinate transmission unit 11 is composed of inverters G2 and G3 for transmitting / receiving signal inversion and a connector 11A with a system transmission line.

In the drawings, reference numerals OP1 and OP2 are operational amplifiers, VCC is a power supply, R1 to R18 are resistors, C1 to C8 are contacts, X1 is a crystal oscillator, VC1 is a voltage comparator, D1 is a diode, and G1 is an inverter.

The coordinate detection operation by the optical coordinate detection apparatus of the present invention configured as described above is as follows.

First, referring to FIG. 3, when power is applied, the CPU 10 selects and controls the light emitting and light receiving elements N to be driven by the light emitting element selection / driver 6 and the light receiving element selection 7. Output the signal SCAN / ADDR (see (a) in Figure 6). It supplies a drive control signal DRIVE CTL for blinking and driving the selected light emitting element for a predetermined number of times (see (c) of FIG. 6).

At this time, the clear signal CLR is supplied to the counter 9 to clear it, and the enable signal EN is supplied to enable the counter signal 9. (See Figures 6 (b) and (f).)

The light emitting element thus selected is turned on / off a predetermined number of times by a drive control signal as shown in FIG. 6C, and an optical signal is received by the light receiving element opposite thereto.

The received optical signal becomes a light receiving signal at the same timing as the transmitted light pulse, and this signal is an electric pulse corresponding to the light receiving signal supplied from the light receiving element selection section 7 to the light receiving signal shaping section 8 as shown in FIG. The waveform is shaped as shown in (d).

The pulse signal is supplied to the counter 9 as a count clock, and counted to a value corresponding to the number of ON / OFF times of the light-emitting element-receiving element previously selected, and the count value is the presence / absence data DATA of the object on the optical path. As input to the CPU 10.

When the selected light emitting element is driven a predetermined number of times, and counted by the counter 9 in which an optical signal is received by the light receiving element as many times as it is driven, it is determined that no object exists on the optical path, and the counted value is determined by the number of driving times. If not, it is determined that an object exists on the optical path and the corresponding coordinate is calculated.

At this time, by analyzing the case in which the object is finely vibrated on the optical path or the count value is changed by the disturbance to determine whether the object is present or not.

This coordinate detection method is based on the frame unit through the repeated configuration of a predetermined number of times in the same path as the sequential configuration on the horizontal / vertical orthogonal path on the coordinate plane to calculate the presence / absence of the object and the coordinates when the object is present. Performing a device scan, counting the received signal detected from the scan result as object detection information per optical path, and comparing the count value with the number of driving of the light emitting devices N which repeatedly constitute the same optical path; In the previous frame, if the object is present, and if the count value is greater than the light emitting element driving frequency (N) in the current frame, the object is determined to exist in the previous frame. If it is less than the light emitting element driving frequency (N), the process of judging that there is no object and the comparison result shows that there is no object in the previous frame. When the count value in the current frame is less than or equal to the reference count value (N) of the presence / absence judgment, the process of judging the presence of an object and the comparison result are determined to be the absence of an object in the previous frame. If the count value exceeds the reference count value M, the process is performed to determine that the object does not exist. The determination of the presence / absence of the object by this is as follows.

First, the meaning of the frame FRAME will be described.

In the present invention, in order to determine the presence or absence of an object blocking light on the screen, one of the light emitting devices arranged on the X-axis and Y-axis as shown in Figs. After a certain number of on / off operations for a period of time, an operation of checking whether a certain number of pulse signals are detected by one light receiving element at a corresponding position is sequentially performed to all light emitting elements and the light receiving element. Determine the presence.

As described above, the operation of checking the presence or absence of an object by sequentially driving the light emitting device and driving a predetermined number of flashes from the first light emitting device to the last light emitting device is called scanning (SCANNING). The one-time scanning result until is called "frame".

Therefore, the previous frame refers to the scanning of all the light emitting and receiving elements arranged immediately before, and the current frame refers to the scanning of all the emitting and receiving elements at the present time.

In the present invention, in order to detect a proper touch operation, for example, the entire light emitting and receiving element is scanned about 30 times per second (30 frames per second), and immediately before each time (every frame) and the scanning result (previous frame) and By comparing the current scanning result (current frame) and changing the result to a coordinate value, touched, touch dropped, etc., a stable touch detection can be achieved.

This operation process will be described with reference to the accompanying drawings.

That is, the touch flag TOUCH FLAG is set to "1" when there is an object in the CPU 10 and to "0" when there is no object, and the touch flag is retrieved.

If the touch flag is clear (= 0) as a result of the search, there is no object in the existing frame.

Therefore, in this case, the count value of the counter 9 is a value (t), (t = M), which adds a value (M) which can increase the number of ON / OFF times (N) of the light emitting element according to the frequency of the external light source. + N).

Therefore, when the count value (data: D) is compared and D≥N, it is determined that no object exists even in the current frame, and the touch flag is cleared.

As a result of the comparison, when a part of the light receiving element is covered by the object and the count value D is N> D> M, it is also determined that the object does not exist.

As a result of the comparison, when the light receiving element is completely hidden and the count value D is M≥D, it is determined that an object exists on the optical path.

On the other hand, when the touch flag search result is set to "1", the object exists in the previous frame.

Therefore, in this case, if the comparison result D <N, a part of the light receiving element is covered and it is determined that it is an incomplete touch, and it is determined that an object exists.

As a result of the comparison, when D≥N, it is determined that there are no obstacles on the optical path, and it is determined that no object exists.

Subsequently, the CPU 10 selects the next light emitting and receiving element N + 1 to receive new count data through the same operation as described above, and performs the same operation on all the light emitting elements and the light receiving elements. .

In this way, the input data becomes the scan of the coordinate system corresponding to one frame, and this scan information is compared with the coordinate system information acquired in the previous frame to determine the presence / absence of the object and to calculate the coordinate (x, y) in the case of the existence of the object. Calculate the coordinate value through, calculate the calculated coordinate value, and supplies the calculated coordinate value to the system side through the coordinate transmission unit (11).

In this way, it is possible to overcome the misjudgment caused by the micro-vibration and to prevent the misbehavior caused by disturbance by varying the interpretation of the count value comparison result depending on whether or not an object exists in the previous frame.

4 is a block diagram of an embodiment of the present invention, and the coordinate detection operation is as follows.

As the CPU 10 operates by applying the power supply VCC, the light emitting diode on / off signal DRIVE CTL is output to the output terminal P0.0, and the light is emitted from the output terminals P2.0 to P2.6. The address signals SA0 to SA6 are outputted for selection of the element and the light receiving element.

The address signals SA3, SA4, SA5, and SA6 are decoded by the decoder 6A to turn on the transistors Q9 to Q18 to light-emitting diodes LD1 to LDy and LDy + 1 to LDx. Is divided into groups, and the address signals SA0, SA1, and SA2 are decoded by the decoder 6B to turn on the transistors Q1 to Q8 to repeat the eight light emitting diodes in the selected group a predetermined number of times. , To drive sequentially.

Light thus output is received by opposing light receiving transistors S1 to Sy and Sy + 1 to Sx.

At this time, the address signals SA3 to SA6 of the CPU 10 are decoded by the decoder 7A to receive the light receiving transistors of the light receiving units 3 and 4 corresponding to the group selected by the light emitting units 1 and 2. A group is selected, and the address signals SA0, SA1, and SA2 are decoded by the analog multiplexer 7B, and the light emitting diodes on / off in the group selected by the light emitting units 1 and 2 are selected. By selecting the light receiving transistor corresponding to the above, the transmission / reception timing of all the transmitted / received light is matched.

Accordingly, the optical signal selected and received is detected by the output terminal X of the multiplexer 7B as a signal such as (a) of FIG. 7, and the signal is an amplifying unit 8A including operational amplifiers OP1 and OP2. Is amplified by and output as shown in (b) of FIG.

The signal output in this way is compared with the reference voltages Ref1 and Ref2 of the waveform shaping in the Schmitt trigger circuit section 8B and is shaped into a pulse as shown in (c) of FIG. 7 as a result of the comparison. 10) is inputted into the counter 9 built in and counted.

In this case, when an object exists in a part of the light receiving path as shown in FIG. 2, the missing waveform is detected and counted as shown in FIGS. 8A and 8B.

The determination of the presence / absence of the object through the analysis of the result of the count and the operation of calculating the coordinates are the same as those of FIGS. 3 and 5, and the coordinate detection information calculated in this way is determined by the inverter G2 and the connector ( It is provided to the general system through 11A), and data from the system side is received through the inverter G3.

As described above, according to the present invention, it is possible to reduce the coordinate detection error due to disturbance in the optical coordinate detection device, to prevent the detection malfunction due to the minute vibration of the touch part, thereby improving the reliability of the operation of the device and There is an effect that can improve the precision.

Claims (3)

The horizontal light emitting portion 1 and the horizontal light receiving portion 3, which face each other in a horizontal direction, are arranged at regular intervals and are arranged at regular intervals, and receive the optical signal. The light emitting elements of the vertical light emitting portion 2 and the vertical light receiving portion 4, and the light emitting elements of the horizontal light emitting portion 1 and the vertical light emitting portion 2, which are arranged to output an optical signal and receive the optical signal; Light-emitting element selection / driver 6 for sequentially flashing a predetermined number of elements per element, and light-receiving elements of light-receiving parts 3 and 4 corresponding to light-emitting elements selectively driven by the light-emitting element selection / driver 6 A light receiving element selecting unit 7 for selecting a light receiving element to selectively detect an optical signal of the light receiving unit, and a light receiving signal outputting a light receiving pulse by shaping the optical signal selected and detected by the light receiving element selecting unit 7 Orthopedic Part (8) And a counter 9 for counting the received pulses output from the light receiving signal shaping unit 8 and outputting the detected information as presence / absence information of the object, the light emitting element selecting / driving unit 6 and the light receiving element selecting unit 7. The CPU 10 for controlling the driving timing of the device and determining the presence of the object and calculating the object touch coordinates by analyzing the count value provided by the counter 9 and the coordinates calculated by the CPU 10. An optical coordinate detection device comprising a coordinate transmission unit (11) for supplying information to a system that needs information. The light emitting diodes (1) of claim 1, wherein the horizontal light emitting portions (1) comprise light emitting diodes (LD1 to LDy) for outputting optical signals, and the horizontal light receiving portions (3) are optical signals output from the light emitting diodes (LD1 to LDy). Is composed of light-receiving transistors (S1 to Sy) for receiving the light, and the vertical light emitting portion (2) is composed of light emitting diodes (LDy + 1 to LDFx) for outputting an optical signal, and the vertical light receiving portion (4) is the light emitting diode. It consists of light-receiving transistors (Sy + 1 to Sx) for receiving an optical signal output to (LDy + 1 to LDx), wherein the light emitting element selection / drive section 6 is a decoder for driving light emitting diodes in group units. 6A and a decoder 6B for selectively driving specific light emitting diodes in the group, wherein the light receiving element selecting section 7 includes a decoder 7A for selecting the light receiving transistors in group units and a specific in the group. Choose light emitting diode It consists of an analog multiplexer 7B for giving and the light receiving signal shaping section 8 converts the amplified light receiving signal into a pulse signal on the basis of a predetermined threshold and an amplifier 8A for amplifying the received light signal. The main circuit is composed of a Schmitt trigger circuit section 8B, and the CPU 10 has a built-in counter 9, and the coordinate transmission section 11 transmits inverters G2, G3 and system transmission for inverting transmission / reception signals. An optical coordinate detection device comprising a connector 11A with a line. Performing a device scan in units of frames through a sequential configuration of light emitting / receiving paths orthogonal to the horizontal and vertical orthogonal structures on the coordinate plane to calculate the presence / absence of the object and the existence of the object; And counting the received light signal detected from the scan result of the scanning process as object detection information per optical path, and comparing the count value with the light emitting element driving frequency (N) constituting the same optical path. In the comparison process, when the count value in the previous frame (the frame in which all light emission and light receiving light scanning is currently performed) is greater than or equal to the number of driving of the light emitting elements, the process of determining that there is an object and the comparison result in the comparison process If it is determined that there is an object in the previous frame and the counter value in the current frame is less than the number of driving of the light emitting device (N), it means that there is no object. And determining that there is no object in the previous frame and the counter value in the current frame is less than or equal to the reference value (M). The optical coordinate detection method comprising the step of determining that there is no object in the previous frame when the comparison result in the comparison process, the object does not exist if the count value in the current frame exceeds the reference count value (M).