JPS5926966B2 - display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device that inputs an instruction signal using a light pen.

In a display device using a cathode ray tube for display purposes, a light pen is brought into contact with the display surface of the display device, and a signal detected from the contact position is generally used as an instruction input signal.

However, when inputting instruction signals using such a light pen, the display surface where the light pen comes into contact must be illuminated, and the non-luminous areas between characters and spaces must be illuminated. There is an inconvenience that no input is made when the light pen is touched. To solve this inconvenience, it is necessary to set the position of contact in advance and project characters on that part and make it emit light, or make the entire surface emit light. However, in the former case,
There are disadvantages that the circuit for projecting the image is troublesome and the places where it can be brought into contact are extremely limited.In the latter case, if the entire surface is emitted, the beam current becomes extremely large and the high voltage fluctuates. The problem was that the size of the raster would change, making it impossible to input accurately. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a device which eliminates such conventional drawbacks, and when a light pen is brought into contact with a display surface, the raster necessary for inputting the light pen is displayed at the end of the raster on the display surface. By emitting light from a small number of parts and moving the light emitting parts sequentially, the beam current can be prevented from increasing excessively and accurate input can be made. The feature is that the light pen can be brought into contact with the position.

EMBODIMENT OF THE INVENTION Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment thereof.

FIG. 1 is a block diagram showing its configuration, and FIG. 2 is a front view of its display surface. In Figure 1, 1 is an extremely stable lock oscillation circuit that generates the basic clock pulse. In this case, it generates a clock pulse with a period equal to the width of one dot in the horizontal direction of characters, etc. to be displayed. .

The dot counter 2 counts clock pulses for each unit of horizontal dots of displayed characters, etc.
If a character or the like is to be displayed as one unit of a dot in the horizontal direction and a dot (b line) in the vertical direction (each including a space), an output is generated each time the clock pulse is counted by a bit. The character counter 3 counts the output for each character generated by the dot counter 2, and generates an output every time it counts the number of characters in the horizontal direction. For example, if only the character C is displayed in the horizontal direction (however, some of the characters are used as a horizontal blanking period), an output will be generated every time the output of dot counter 2 is counted by C bits. . Therefore, the output of the character counter 3 is generated every horizontal period, and is used to generate a horizontal synchronizing signal in the horizontal synchronizing signal generating circuit 4. Further, the write counter 5 counts the output of the character counter 3, and generates an output every time one vertical line is counted.

Here, as described above, one unit is composed of b dots (b lines), so an output is generated each time the output of the character counter 3 is counted by b bits. Finally, the line counter 6 counts the output of the line counter 5 and generates an output every time it counts the number of lines in the vertical direction. For example, if only d lines are displayed in the vertical direction (however, some of these lines are used as a vertical blanking period), an output is generated every time the line counter 5 counts d bits. Therefore, the output of the row counter 6 is generated every vertical period, and is used to generate a vertical synchronization signal in the vertical synchronization signal generation circuit 7. Then, the processing circuit 8 performs necessary arithmetic processing and signal processing using each of these outputs, input means, data input from the memory, etc., and generates data output.

The display signal generation circuit 9 generates a display video signal suitable for displaying the data information based on this data output, and inputs the data information to the cathode ray tube 11 via the 0R gate 10. indicate. In addition, when the light pen 12 comes into contact with the display surface of the cathode ray tube 11, it generates a light emission detection output at the contact position, and after performing predetermined signal processing in the light pen input circuit 13, a command is issued. It is supplied to the processing circuit 8 as an input signal.

The above portions are similar to conventional display devices.

Next, in this device, in order to input a command signal by bringing the light pen 12 into contact with an arbitrary position on the display surface, when the light pen 12 is brought into contact, the cathode ray tube 11 is activated. Lights up the display screen one line per field,
In addition, the row where the light is emitted is sequentially moved from Hijikata's row to the lower row for each field, so that all positions on the entire surface of the display surface are emitted in one way in the d field.

For this purpose, first, the output of a binary n-bit row count indicating which row is being scanned is taken out from the row counter 6 and applied to one input of the comparison circuit 14.

On the other hand, a contact detection switch 15 is built into the light pen 12 so as to be closed when the light pen 12 comes into contact with an arbitrary position on the display surface of the cathode ray tube 11 and is pressed.
A memory circuit 16 consisting of a flip-flop or the like is set to detect the contact and to store the fact that the contact has been made. Furthermore, the field counter 17 is enabled to count by the output when it is set, and thereafter, the vertical synchronizing signal is counted by the field counter 17. Then, the output obtained by counting the field is added as the other input of the comparator circuit 14. In this way, the field counter 17 generates a count output that changes for each field, so when the comparison circuit 14 compares this field count output with the previous row count output and the two match, If the general output is generated, the first field will be generated only during the first line scanning period, the second field will be generated only during the second line scanning period, and the dth field will be generated only during the dth line scanning period. Only during the scanning period, a coincidence output can be obtained that moves successively downward row by field, and so on. Therefore, by applying this coincidence output to the cathode ray tube 11 through the 0R gate 10, the display screen can be illuminated while moving downward one field at a time from the top row, and the d field It is possible to cause the entire display surface to emit light in one manner during the period. Incidentally, when a light emission detection output is generated by the light pen 12 and applied to the processing circuit 8 from the light pen input circuit 13, it is preferable to reset the memory circuit 16 with the input confirmation signal. Therefore, no matter which position on the display surface the light pen 12 contacts, even if no characters are displayed at that contact position, the light emitting portion that moves sequentially as described above will cause the d field period to change. Be sure to have a light pen 12 between
Since it is possible to detect light emission at a position, it is possible to accurately and easily input a command signal at an arbitrary position.

Moreover, in this device, the cathode ray tube 11 emits light only for one line per field, and because it emits light in small portions at a time, the beam current becomes excessive and the display position is distorted. It also has the advantage of realizing extremely stable and accurate input without fear of deviation. In the above embodiment, one line is emitted per field, but any number of lines may be emitted as long as each field is emitted at a time. It goes without saying that the light-emitting portion may also be made to emit light discontinuously, for example, one line every several lines, instead of consecutively for several lines.

Furthermore, if the output of the character counter 3 is added to the field counter 17 in FIG. 1 instead of the count output of the line counter 6, it is possible to divide the horizontal direction into a plurality of sections and emit light for each section. become. In this case as well, the light-emitting portions may be formed into vertical columns of any number of dots, or may be formed into discontinuous vertical lines. As described above, according to the present invention, it is possible to always input a command signal from the light pen regardless of the position of the display surface in contact with the light pen, and moreover, it is possible to input a command signal from the light pen regardless of the position of the display surface where the light pen comes into contact. Therefore, it is possible to obtain an excellent device that can prevent such problems and perform accurate input.

That is, in a display device using a cathode ray tube, if the entire surface of the cathode ray tube is made to emit light at once, the anode high voltage will fluctuate due to an increase in the beam current, which will cause the amplitude of the display screen to fluctuate. It becomes impossible to accurately detect the position where the light pen is applied, but
By limiting the light emission to a small number of portions as in the present invention, it is possible to eliminate such inconvenience caused by an increase in beam current, and accurate light pen detection can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a display device according to an embodiment of the present invention, and FIG. 2 is a front view of its display surface. 1...Clock oscillation circuit, 2...Dot counter, 3...Character counter, 4...
...Horizontal synchronization signal creation circuit, 5 ... Line counter, 6 ... Line counter, 7゜゜゜ ... Vertical synchronization signal creation circuit, 8 ... Processing circuit, 9 ...
...Display signal generation circuit, 10...0R gate, 11...Cathode ray tube, 12...Light pen, 13...Light pen input circuit , 14・
... Comparison circuit, 15 ... Switch, 16
...Memory circuit, 17...Field counter.

Claims (1)

[Claims] 1 A cathode ray tube for display, a light pen that comes into contact with the display surface of the cathode ray tube for display and inputs a signal indicating the contact position by detecting the emitted raster on the display surface, and the above-mentioned light. a detecting means for detecting that the pen is brought into contact with the display surface; and a detecting means for detecting that the pen is brought into contact with the display surface, and a raster to be detected by the light pen among the rasters on the display surface of the cathode ray tube when a detection output is generated from the detecting means. A display device comprising means for generating and supplying a video signal to the cathode ray tube so that a small number of the light emitting parts emit light and sequentially moving the light emitting parts.