JPH05173699A - Coordinate input device - Google Patents

Abstract

PURPOSE:To prevent wrong coordinate output due to a noise as to the optical system coordinate input device which is constituted by arranging pairs of light emitting and receiving elements in matrix and calculates an input coordinate position from their light quantity measured values. CONSTITUTION:The pairs of light emitting and receiving elements are driven, pair by pair, and the quantities of received light of the light receiving elements are measured to calculate coordinates from the positions of the light emitting element and light receiving element whose optical path is cut off (step 107). The quantity of light between the pair of light emitting and receiving elements at (b)th positions corresponding to the calculated coordinates is measured again (step 108), and it is decided whether the optical path is cut off or not (step 109). Only when the optical path is cut off, it is judged that the calculated coordinates are manually inputted coordinates, and coordinate output is performed (step 11).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device, and more particularly to an optical coordinate input device in which pairs of light-emitting / light-receiving elements are arranged in a matrix and an input coordinate position is calculated from measured values of their light quantities.

[0002] coordinate input apparatus for an optical system, X in the horizontal direction as shown in FIG. 4 _m pieces arranged for example light emitting diodes (L
ED) 1 and X arranged facing each other in a one-to-one correspondence
_m number of phototransistors 2 and Y _{n in} the vertical direction
The coordinate detection area 5 is formed by the LEDs 3 arranged individually and the Y _n phototransistors 4 arranged facing each other in a one-to-one correspondence.

When a touch input is made to, for example, the touch portion 6 in the coordinate detection area 5, the touch portion 5 is touched.
Since the optical path passing through is blocked, the amount of light received by the phototransistors 2 and 4 in the blocked optical path is reduced. Therefore,
The positions of the phototransistors 2 and 4 where the amount of received light has decreased are averaged to calculate the position 7 of the touch coordinates.

Such a coordinate input device is required to be constructed so as not to be affected by noise such as changes in external light and power supply fluctuations.

[0005]

2. Description of the Related Art A conventional optical type coordinate input device is shown in FIG.
The input coordinate position is detected according to the flowchart shown in FIG. First, after setting the variable n to "1" (step 201), the amount of received light is measured from the output detection signal of the nth (that is, the first here) photodetector (phototransistor 2 or 4) (step 201). 202).

Whether or not the above measured value is larger than a threshold value is compared, and when the measured value is equal to or larger than the threshold value, the light path between the first phototransistor 2 or 4 and the LED 1 or 3 is not blocked (ON. ), And when it is less than the threshold value, it is determined that the optical path is blocked (OFF) (step 203).

Then, after incrementing the value of the variable n by "1" (step 204), it is judged whether or not the value of the variable n is larger than the number of elements in the scanning direction (step 20).
5), when the number of elements ≧ n, steps 202 to 20 are performed again
Process 4 is performed. In this way, the opposing LED1
Alternatively, if the presence or absence of interruption of the optical path between the phototransistor 3 and the phototransistor 2 or 4 is determined (scanned) for all the elements in the horizontal direction or the vertical direction, the process proceeds to step 206 and all the elements in the scanning direction are performed. It is determined whether or not the optical path of the element is blocked (off).

When the optical paths of all the elements are off, the processing of this flowchart is immediately terminated, and when not off, the positions of the LED 1 or 3 and the phototransistor 2 or 4 pair in the off optical path are averaged to calculate the coordinates. (Step 20
7) The calculated coordinates are output (step 208).

Next, this time, scanning is performed in a direction orthogonal to the previous scanning direction, coordinates are calculated in the same manner as described above (steps 201 to 207), and the calculated coordinates are output (step 208).

[0010]

However, in the conventional coordinate input device, when the light interruption is detected and the coordinates are calculated, the coordinates are unconditionally output as the input coordinates. Even if the amount of light changes momentarily due to noise, it may be detected as an input coordinate and the wrong coordinate may be output.

The present invention has been made in view of the above points,
An object of the present invention is to provide a coordinate input device that solves the above problems by confirming the continuation of light blocking of a light emitting element and a light receiving element pair at a position corresponding to calculated coordinates.

[0012]

FIG. 1 is a block diagram showing the principle of the present invention. As shown in the figure, in the coordinate input device of the present invention, a plurality of pairs of light emitting elements and light receiving elements facing each other at a distance are arranged in the horizontal direction and the vertical direction, respectively.
In the coordinate input device for detecting an input coordinate to the coordinate input region 15, the region where the optical path formed by the pair of the light receiving elements 13 and 13 is formed in a matrix is used as the coordinate input region 15. The configuration has a calculation means 17, a second determination means 18, and a coordinate output means 19.

Here, the first judging means 16 sequentially drives the plurality of pairs of the light emitting elements and the light receiving elements for each pair to measure the amount of light received by the light receiving elements 12 and 14, and determines the pair of light emitting elements. Whether or not the light path between the light receiving elements is blocked is determined for all pairs.

The coordinate calculating means 17 is the first judging means 16
The input coordinate position is calculated from the position of the pair of the light emitting element and the light receiving element which is determined to be the optical path cutoff based on the determination result of.

The second judging means 18 is the coordinate calculating means 17
The amount of light received by the light receiving element at the position corresponding to the coordinates calculated by the above is measured to determine whether or not the optical path interruption continues.

Further, the coordinate output means 19 outputs the coordinates calculated by the coordinate calculation means 17 as the input coordinates when the second judgment means 18 obtains the judgment result of the continuation of the optical path.

[0017]

In the present invention, the second judging means 18 again measures the light quantity of the pair of the light emitting element and the light receiving element at the position corresponding to the calculated coordinates to judge whether or not the optical path is interrupted. The time required for this determination is longer than the change in the amount of light due to noise such as change in external light or power supply fluctuation, while it is sufficiently shorter than the change in the amount of light when a person inputs coordinates. Therefore,
As a result of the judgment by the second judging means 18, it is possible to discriminate whether the light path interruption is due to noise or due to the coordinate input. Further, the confirmation of the optical path interruption after the coordinate calculation is performed only for the pair of the light emitting element and the light receiving element corresponding to the coordinate calculation position.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 shows a block diagram of an embodiment of the present invention. In the figure, a light emitting element array 21 and a light receiving element array 22 in the horizontal direction are spaced apart and faced to each other, and a light emitting element array 23 and a light receiving element array 24 in the vertical direction are spaced apart from each other, and a space portion surrounded by these is formed. Coordinate input area 25 (corresponding to the coordinate input area 15)
It is said that.

The light emitting element array 21 is composed of m light emitting elements (for example, LEDs) corresponding to the light emitting elements 11 arranged in the horizontal direction at regular intervals, and the light receiving element array 22 is paired with the m light emitting elements. It is composed of m light receiving element rows (corresponding to the light receiving elements 12, for example, phototransistors) facing each other. Therefore, a total of m optical paths are formed in parallel between a pair of light emitting elements and light receiving elements facing each other in the horizontal direction.

Similarly, the light emitting element array 23 is composed of n light emitting elements corresponding to the light emitting elements 13 arranged in the vertical direction at regular intervals, and the light receiving element array 24 is the n light emitting element array 23. It is composed of a total of n light receiving elements (corresponding to the light receiving element 14) facing the light emitting element with a space therebetween, and n optical paths are formed in parallel with each other.

As a result, in the coordinate input area 25, m optical paths formed in the horizontal direction and n optical paths formed in the vertical direction can intersect in a matrix. However, as will be described later, in order to prevent light interference, only one (m + n) optical paths are formed at the same time, and they are sequentially formed in a time division manner.

The light emitting element switching section 26 switches and drives each of the light emitting elements of the light emitting element rows 21 and 23 one by one. The light receiving element switching unit 27 switches each of the light receiving elements of the light receiving element rows 22 and 24 one by one, and selectively outputs a detection signal according to the received light amount.

The control unit and the data storage unit 28 send switching control signals to the light emitting element switching unit 26 and the light receiving element switching unit 27, respectively, to sequentially switch the pair of opposing light emitting element and light receiving element. A / D along with (scan)
A clock is sent to the conversion unit 29 to convert the detection signal from the light receiving element switching unit 27 into analog / digital conversion.

The on / off determination section 30 is an A / D conversion section 29.
In the circuit unit which compares the magnitude with a threshold value held in advance based on the digital data from, determines that the digital data is larger than the threshold value is ON, and is smaller than the threshold value is OFF (optical path cutoff). The determination means 16 of 1 constitutes. The threshold value is larger than the digital value of the received light amount detection signal of the light receiving element when the light from the light emitting element is not incident on the light receiving element, and the light from the light emitting element is normally received. It is set to a value smaller than the digital value of the received light amount detection signal of the light receiving element at that time.

The coordinate calculation unit 31 is a circuit unit for calculating the coordinates of the optical path blocking setting in the coordinate input area 25 based on the determination result of the ON / OFF determination unit 30 stored in the control unit and the data storage unit 28. The coordinate calculation means 17 is configured. The coordinate output unit 32 is a circuit that outputs the coordinates calculated by the coordinate calculation unit 31 when a coordinate output control signal is input from the control unit and data storage unit 28, and constitutes the coordinate output means 19. ..

Further, the control / data storage unit 28 determines from the ON / OFF determination unit 30 again whether the optical path between the pair of the light emitting element and the light receiving element at the position corresponding to the coordinates calculated by the coordinate calculation unit 31 is blocked. The coordinate output control signal is sent to the coordinate output unit 32 only when the presence or absence of the optical path interruption is detected again based on the determination result of 1. Therefore, the control unit and the data storage unit 28 have the function of the above-described second determination unit 18.

Next, the operation of this embodiment will be described with reference to the flow charts of FIGS. First,
The control unit and the data storage unit 28 sets the value of the variable a to the initial value "1" (step 101) and measures the light quantity of the a-th (here, the first) optical path (step 10).
2). For example, the light emitting element switching unit 26 is controlled only for the leftmost light emitting element of the light emitting element array 21 to supply a drive signal to cause the light emitting operation, and only the signal from the leftmost light receiving element of the light receiving element array 22 is selected. The light receiving element switching unit 27 is controlled so as to be output.

As a result, light from the leftmost light emitting element of the light emitting element array 21 is received by the leftmost light receiving element of the light receiving element array 22, and a detection signal of a level corresponding to the amount of received light is extracted from the leftmost light receiving element. .. This detection signal level is maximum when there is nothing that blocks the optical path between the light emitting element and the light receiving element at the left end, and is minimum when there is something that blocks.

The detection signal photoelectrically converted by the light receiving element and taken out is supplied to the A / D conversion section 29 through the light receiving element switching section 27, where it is converted into digital data having a value according to the level. After that, the on / off determination unit 30 performs the above-described on / off determination (step 10).
3).

When the ON / OFF determination result from the ON / OFF determination section 30 is input to the control section and data storage section 28, the value of the variable a is subsequently incremented by "1" (step 104), and the increment is performed. It is determined whether the value of the subsequent variable a is larger than the number of elements in the horizontal direction (step 105), and if a ≦ (number of elements), step 10
Returning to step 2, an optical path is formed between the second element from the left end of each of the light emitting element array 21 and the light receiving element array 22, and the light quantity is measured.

Then, similarly to the above, the on / off determination of the amount of light received by the second light receiving element from the left end (step 10).
3), the variable a is counted up (step 104), and the size of the variable a and the number of elements are compared (step 105). In this way, when the light amount between the respective elements from the left end to the right end of each of the light emitting element array 21 and the light receiving element array 22 is sequentially measured, a> the number of elements, so the control unit and the data storage unit 28 perform the measurement. It is determined whether or not all the elements have been turned off (step 106).

If all are off, it is determined that the device is abnormal and coordinates are not calculated, and the process ends. On the other hand, when all the elements have not been determined to be off, the on / off determination result is input to the coordinate calculation section 31 through the control section and the data storage section 28, and the input coordinates (here X The coordinates) are calculated (step 107).
At this time, when there are a plurality of light receiving elements that are determined to be off, the average value of them is calculated as the input coordinate.

The above-described operation is similar to that of the conventional apparatus, but the present embodiment is different from the conventional apparatus in that the processing of subsequent steps 108 and 109 is performed. That is, when the input coordinates are calculated, the control unit and the data storage unit 28 determines the position corresponding to the calculated coordinates (for example, this is the b-th position from the left end).
The light amount is measured only for the optical path between one light emitting element and one light receiving element to determine whether or not the optical path is blocked (step 108).

When the on / off determination section 30 makes an on / off determination based on the light quantity measurement result, the control section and the data storage section 28 determines whether or not the optical path interruption is continued based on the on / off determination result. Judge (Step 10
9).

Here, the change of the light amount due to noise such as the change of the external light or the fluctuation of the power source is pulsed, and the above-mentioned step 1 is performed.
It is shorter than the time from the light intensity measurement time of the bth optical path calculated as the input coordinate of 02 to the time when the measurement of the bth optical path is restarted in step 108 after the coordinate calculation. On the other hand, when a person inputs a desired touch coordinate to the coordinate input area 25 with a finger or an instrument, it is sufficiently longer than the time until the remeasurement of the light quantity of the b-th optical path.

Therefore, when it is determined in step 109 that the optical path is interrupted, it is determined that the calculated coordinates are based on the normal coordinate input by the human being, and the control unit and the data storage unit 28 determine the coordinates. A coordinate output control signal is sent to the output unit 32 and the coordinate output unit 32 outputs the calculated coordinates (step 110).

On the other hand, when it is determined in step 109 that the optical path interruption is not continued, it is determined that the calculated coordinates are due to the noise caused by the change of the external light or the fluctuation of the power source, and the control unit Also, the data storage unit 28 does not send the coordinate output control signal to the coordinate output unit 32, and does not output the coordinate.

When the coordinate calculation process for the X coordinate is completed in this way, the control unit and data storage unit 28 sets the value of the variable a to "1" again (step 10).
1) This time, in steps 102 to 110, the amount of light on the optical path between the light emitting element array 23 and the light receiving element array 24 is sequentially measured, and the Y coordinate is calculated and output.

As described above, according to the present embodiment, it is possible to prevent the output of the coordinate which is erroneously calculated due to noise, and the confirmation of the optical path interruption after the coordinate calculation is performed only for the pair of the light emitting element and the light receiving element at the calculated coordinate position. Therefore, the influence on the detection speed is extremely small.

The present invention is not limited to the above-mentioned embodiment, and for example, the light quantity measuring scan in units of a pair of a light emitting element and a light receiving element in steps 101 to 105,
Both the horizontal direction and the vertical direction may be collectively performed (in this case, not the sequence of X coordinate calculation → coordinate output → Y coordinate calculation → coordinate output, but calculation of X coordinate and Y coordinate → X coordinate and It becomes a sequence of Y coordinate output). The present invention can also be applied to crime prevention using an infrared light emitting element and a light receiving element.

[0041]

As described above, according to the present invention, it is possible to distinguish whether the optical path cutoff in the input coordinate area is due to noise or due to a human being, so that only the coordinates input by a human are accurately calculated and output. Since the confirmation of the interruption of the optical path after the coordinate calculation is performed only for the optical path between the pair of the light emitting element and the light receiving element corresponding to the coordinate calculation position, the coordinate detection speed is not lowered and accurate input can be performed. It has features such as coordinate detection.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of the embodiment of the present invention.

FIG. 4 is a configuration diagram of an example of a main part of a coordinate input device.

FIG. 5 is a flowchart for explaining the operation of an example of a conventional device.

[Explanation of reference signs] 11,13 Light emitting element 12,14 Light receiving element 15,25 Coordinate input area 16 First judging means 17 Coordinate calculating means 18 Second judging means 19 Coordinate output means 21,23 Light emitting element array 22,24 Light receiving element array 28 Control unit and data storage unit 30 ON / OFF determination unit 31 Coordinate calculation unit 32 Coordinate output unit

Claims (2)

[Claims] 1. A plurality of pairs of a light emitting element and a light receiving element facing each other at a distance are arranged in a horizontal direction and a vertical direction, respectively, and a plurality of pairs of the light emitting element (11, 13) and the light receiving element (12, 14) are provided. A coordinate input device (15) in which a region where optical paths are formed in a matrix is used as a coordinate input region (15), and a coordinate input device for detecting an input coordinate to the coordinate input region (15), wherein a plurality of pairs of light emitting elements and light receiving elements are paired. A first determining means (16) for sequentially determining the presence / absence of an optical path interruption between the light emitting element and the light receiving element to be paired by sequentially driving the light receiving elements (12, 14). Coordinate calculating means (17) for calculating an input coordinate position from the position of the pair of the light emitting element and the light receiving element which is determined to be an optical path cutoff based on the determination result of the first determining means (16), and the coordinate calculating means ( To the coordinates calculated by 17) Second determination means (1) for determining whether or not the optical path is interrupted by measuring the amount of light received by the light receiving element at a corresponding position.
8) and when the second determination means (18) obtains the determination result of continuation of the optical path, the coordinate output means (19) for outputting the coordinates calculated by the coordinate calculation means (17) as input coordinates. A coordinate input device comprising: 2. The second judging means (18) blocks the optical path only for the optical path between the pair of the light emitting element and the light receiving element at the position corresponding to the coordinates calculated by the coordinate calculating means (17). The coordinate input device according to claim 1, wherein presence / absence is determined.