JPS5843750B2 - Zahiyoukenshiyutsuhoshiki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting an arbitrary position (coordinates) on a display body in which light emitting elements are arranged in a matrix.

In order to detect the coordinates of an arbitrary position in a display body in which light emitting elements such as light emitting diodes are arranged in a matrix, the following method is generally used.

In other words, the display is driven so that it lights up dot-sequentially, the lighting of the light emitting element at the detected position is detected by a light pen having a light receiving means such as a photoelectric conversion element, and this detection time (lighting time) is detected.
The coordinates are detected by comparing the time with the reference time.

Regarding point sequential lighting drive, 3×37) I shown in Figure 1
This will be explained by taking a J rack light emitting element (light emitting diode) display body as an example.

Figure 2 shows the row direction electrode lines (scanning lines) Xl and X2 in Figure 1.
．． X3 and column direction electrode lines (scanning lines) Yl, Y2. Y3
FIG. 3 is a diagram showing a time chart of voltage signals applied to each electrode line of FIG.

In the figure, A is a clock signal for synchronization, C, C, and B are row direction electrode lines X1. X2. E, H, G for each line of X3 are column direction electrode lines Y0. Y2. The voltage signals applied to each line of Y3 are shown.

In addition, the magnitude of each applied voltage value is such that when applied alone, the light emitting element does not light up even if a voltage is applied in the direction of lighting the light emitting element, and the voltage is applied to both the row electrode and the column electrode in the direction of lighting the light emitting element. The size is such that the light emitting element lights up only when the light is turned on.

As is clear from Fig. 2, each row direction electrode line (Xl,
X2. X3) corresponds to the clock signal of A, and X7. X
2. A voltage signal is applied in the order of X3, goes around in a cycle corresponding to the number of rows (three rows in this case), and the applied voltage signal is repeated again in the same order.

For example, focusing on the row direction electrode line X2, a voltage is applied to the row electrode X2 with the second clock signal, and thereafter, a voltage is applied every third pulse (one period).

On the other hand, each column direction scanning line (Y, , Y2, Y3) has a voltage signal having a width for the number of rows (width for one cycle), Yl,
Y2. Y3, and the applied voltage signal is repeated in the same order for every number of columns (three columns in this case).

For example, if we focus on the second column electrode Y2, the voltage is applied to the column electrode Y1 during the clock signal (3 pulses) corresponding to the number of rows (one cycle period), and then the voltage is applied to the column electrode Y1 during the clock signal (3 pulses) corresponding to the number of rows. A voltage is applied to electrode Y2.

Thereafter, the application is repeated at a total display surface scanning period T of 3×3=9 pulses (since mold pressure is applied during 3 pulses, the non-application period is 6 pulses).

In order to light up a light emitting element, it is necessary to apply a voltage in the lighting direction to the row electrodes and also to apply a voltage in the lighting direction to the column electrodes.

In FIG. 2, row electrode X1. It is assumed that the voltage applied in the lighting direction to X2°X3 is upward (convex portion), and the voltage is applied in the extinguishing direction to areas other than the convex portion.

(The application of voltage in the direction of extinguishing the light may not be applied, that is, it may be stopped.

) Hereinafter, in the row electrodes, the voltage applied in the lighting direction (convex portion in the figure) is referred to as high level, and the voltage applied in the extinguishing direction (concave portion in the figure) is referred to as low level.

On the other hand, column electrode Y1. Y2. The voltage applied to Y3 in the lighting direction is shown in the downward direction (concave portion) in FIG. 2, and the turning off direction is shown in the upward direction (convex portion).

In the column electrodes, when voltage is applied in the lighting direction (concave portion in the figure), it is called low level, and when voltage is applied in the extinguishing direction (convex portion in the figure), it is called high level.

For example, when the row electrode X1 becomes high level and the column electrode Y1 becomes low level, the light emitting element a1□ lights up.

Each light emitting element a on the matrix, (Xl, Y, E
a12 (Xi, Y2), ah3 (Xl, Y3)
,”””.

a33 (X3.Y3) is lit sequentially in this order 1
FIG. 2H is a time chart showing the lighting state of the light emitting element a22 (X2, Y2), and the shaded area indicates light emission.

In this way, each light emitting element on the matrix has a period T
Pulsed light is emitted at , and all the light emitting elements are sequentially scanned and turned on within period T.

Therefore, the coordinates of the light emitting element at the detected position (light pen installation position) can be detected by comparing the time (within period T) of the light pen's light reception with the clock signal.

Fig. 2 H shows an example of detecting the position of the light emitting element a22 (detecting the position of the light receiving element placed at the position a22), but if the number of rows and columns is known in advance, then , this position (coordinates) can be easily detected.

For example, assuming that the pulses for the number of rows (3 pulses in the example in FIG. 1) are the reference width, the Y coordinate is determined by the number of reference widths that fall between the reference time (start of period T) and the timing position of the light receiving element a22. The X coordinate can be found from the number of pulses that fall between the delimiter of the reference width and the light-receiving element timing position.

As described above, in the conventional coordinate detection method, the light emitting element matrix is driven so as to turn on point-by-point, and this is used to detect the coordinates.

However, in such conventional methods, only one element lights up, so as the number of elements that make up the matrix increases, the lighting time per element becomes correspondingly shorter.
The amount of light emitted from the device is significantly reduced.

For example, if the number of elements is n, the light emitting time per element cannot exceed 1/n, so the average brightness of the display decreases, the screen becomes dark, and this also impedes coordinate detection. It turns out.

One way to increase the average brightness of lit light is to increase the instantaneous drive current by increasing the instantaneous brightness, but as the number of elements increases, it is not possible to flow a sufficient instantaneous drive current due to the maximum instantaneous current limit of the elements. , it becomes difficult to maintain the required average brightness.

The present invention was made in view of the shortcomings of the conventional coordinate detection methods, and provides a novel coordinate detection method that maintains the brightness of the screen of the display body at a high level and enables effective coordinate detection. This is what we provide.

The present invention reverses the applied voltage direction of the voltage signal applied to the light emitting element from the conventional point-sequential lighting drive, detects the extinguishment of the detected element, and compares this extinguishing timing time with a reference time based on a clock signal. By this, the coordinates of the detected position (element) are detected.

A method of applying voltage to the light emitting elements of a display body used in the present invention will be explained in detail with reference to FIG. 3, taking each electrode of the 3×3 matrix light emitting element (light emitting diode) display body shown in FIG. 1 as an example.

In FIG. 3, A2 and C are row electrodes X1 and C. X2. Two to X3, ho.

to column electrode Y1. This is a time chart showing the voltage waveforms applied to Y2 and Y3, respectively, of the D-type flip-flops FF, ~FF, which constitute the light emitting element drive circuit of FIG.
6.

As is clear from Figure 3, the voltage applied to each row electrode and each column electrode has the opposite polarity (high level and low level are reversed) compared to the conventional dot sequential lighting drive shown in Figure 2. In the dot-sequential lighting drive, the voltages applied to the lighting side (row electrodes are at a high level and column electrodes are at a low level) are applied so that they have opposite polarities (row electrodes are at a low level and column electrodes are at a low level). .

Figure 3 shows a2 of the matrix light emitting elements in Figure 1.
2 (X2.Y2) is a time chart showing the light emission state.

(The shaded area indicates light emission.) As is clear from this figure, the light emitting element a22 has a period when the column electrode Y2 is at a high level (convex portion) and a period when the column electrode Y2 is at a low level (concave portion) and the row electrode
The light goes out every period when it is at the crow level (concave part),
The former has a long turn-off time, while the latter has a short turn-off time.

The combination of these two types of long and short extinguishing pulses is different for every element within a period (one cycle) T, and it is possible to detect the position (coordinates) of the element from the combination of the positions (timings) of these long and short pulses. .

For example, the light emitting element a2° (X2° Y2) shown in Figure 3
To detect the coordinate position of The X coordinate (X2) can be determined by comparing the detection timing of the light-off pulse with the reference time.

Figures 5a, b, and C are circuits for determining the X and Y coordinates, and Figure 6 is a signal waveform diagram at each point in the same circuit. The emission needle receives the desired light and amplifies it to form the detection signals Pout and D'RF.

At point A of the photodetector circuit, the clock during the light reception period is
At the point, a clock waveform can be formed during non-light reception.

The detection signal RF is input to the flip-flop FF7 to which the clock signal φX1 of the X value detection circuit shown in FIG. A signal reset by the pulse at the time of light emission is output.

Therefore, by counting the number of pulses during the output period of the Noritsubu flop FF7 with the counter C1, the position of the light emitting element on the X axis can be detected.

Figure 5C to which the detection signal Pout is applied is a Y value detection circuit, and the waveform output to point E of flip-flop FF8 is the Pout waveform delayed by 1 bit using the clock CLK, and the X-axis is Non-emission pulses can be removed from display.

The H signal sets the flip-flop FF, and the E signal resets the flip-flop 7'FF9.

While the flip-flop FF9 is set, the Y-axis value of the light emitting element can be detected by counting the clock signal X2 with the counter C2.

The GP signals input to the latch circuits L1 and L2, respectively, are generated by operating the switch SW1, and latch the X and Y values detected by the counters C1 and C2.

A coordinate position is detected based on the detected X-axis and Y-axis values.

In the coordinate detection method of the present invention, the light emitting elements are turned off for each column and row of the coordinates where the light emitting elements are present, so that the luminance of the entire display surface is high and effective display can be performed.

This effect becomes more pronounced as the number of light emitting elements forming the matrix increases.

The coordinates detected by the method of the present invention are usefully used for various types of signal processing later.

For example, when newly writing or erasing information at an arbitrary position, this method can be used to easily detect the coordinates of that position and feed this back to the drive circuit for each scanning line.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a (3x3) light emitting element matrix, Fig. 2 is a time chart of the conventional coordinate detection method, Fig. 3 is a time chart of the method of the present invention, and Fig. 4 is a circuit diagram of a light emitting element matrix according to the present invention. 5A, 5B and 5C are circuit diagrams for explaining the present invention, and FIG. 6 is a signal waveform diagram for explaining the same circuit.

Claims (1)

[Claims] 1. In a method for detecting the coordinate positions of a group of light emitting elements in a matrix arrangement that turn on and off in synchronization with a reference clock signal, each light emitting element is connected to a first group of electrodes that intersect with each other. The intensity of the voltage applied to the first electrode group and the second electrode group is such that the intensity of the voltage applied to the first electrode group and the second electrode group is such that the light emitting element lights up only in one of the electrode groups. The light emitting element can be lit even if a voltage is applied in the direction, and the intensity is such that the light emitting element is lit only when a voltage is applied to both electrode groups in the direction that the light emitting element is lit. , Normally, a lighting voltage is applied in the direction to turn on the light emitting element, and at a timing synchronized with the reference clock signal, a turn off voltage in the direction to turn off the light emitting element for a period corresponding to the clock pulse width is applied to each electrode wire. A turn-on voltage is applied to the second electrode group at all times, and a turn-off voltage of the interval is applied to each electrode line in turn at intervals of one cycle of application of the erase voltage to the first electrode group. The matrix light emitting element A coordinate detection method characterized by detecting the coordinates of an arbitrary position of a group.