JPS638486B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a CRT display device having a function of determining which of a plurality of CRTs is being indicated by a light pen in a system for indicating coordinates on a CRT using a light pen. .

Conventionally, data in multiple storage devices is scanned based on the same synchronization signal and corresponding to each
In a system where the display is displayed on a CRT and control is performed by pointing a light pen at one of the CRTs, the control circuit determines which CRT the signal from the light pen comes from. Unable to determine, a separate switch was installed to match the CRT indicated by the light pen.

However, this configuration has the disadvantage that the CRT indicated by the light pen and the changeover switch do not automatically correspond, making the operation complicated. The present invention has been proposed with the aim of eliminating such drawbacks, and is intended to automatically determine which CRT is indicated when a light pen indicates one of a plurality of CRTs. .

A detailed description will be given below with reference to the drawings.

Figure 1 shows the configuration of a system using a conventional light pen and CRT.
is input to the synchronization signal generation circuit 1, generates a horizontal synchronization signal H and a vertical synchronization signal V, and inputs them to the horizontal/vertical deflection circuit 13. The CRT A7 and CRT B8 are scanned by the output of the horizontal/vertical deflection circuit 13. At the same time, clock O is address counter 2.
The address counter 2 receives the address signal ADD for the storage device A3 and storage device B4.
Output. The address signal ADD is also input to the latch 10 in order to detect the address corresponding to the coordinates indicated by the light pen 9. The data output from the storage device A3 is input to the D/A conversion circuit 5, converted into an analog signal,
Displayed on CRT/A7. On the other hand, storage device B
The data outputted from 4 is input to a D/A conversion circuit 6 and displayed on a CRT/B8 as an analog signal. The light pen 9 receives a bright line detection signal l.
It also outputs a light pen switch signal (SW) that automatically turns on when the light pen presses the CRT surface, and this causes the latch 10 to
Latch the output of address counter 2. Therefore, the address latched by the latch 10 corresponds to the coordinates indicated by the light pen, and is input to the write data control circuit 11 and stored in the storage device A as appropriate.
3 and rewrite the contents of storage device B4. However, at this time, which of the storage device A3 and storage device B4 is accessed is controlled by the changeover switch 12.

According to such a configuration, as described above, it is necessary to operate a changeover switch, and therefore, it lacks operability.

FIG. 2 shows the internal configuration of the device of the present invention,
In FIG. 2, a synchronizing signal generation circuit 1, a horizontal/vertical deflection circuit 13, an address counter 2, a storage device A3, a storage device B4, D/A conversion circuits 5, 6,
Each operation of the CRT/A7, CRT/B8, light pen 9, latch 10, and write data control circuit 11 is
Same as in the figure. In the present invention, after detecting the light pen switch signal SW obtained when the light pen is pressed onto the CRT, the bright line detection signal of the light pen is accepted for only one field.
Coordinate detection circuit 2 that detects the coordinates indicated by the light pen
5 operates, and the area sampling circuit 26 receives the coordinate detection signal AD from the coordinate detection circuit 25 and generates a pulse AR to sample the area near the coordinates indicated by the light pen 9.
Output. The signal AR, vertical synchronization signal V, light pen switch signal SW, and bright line detection signal l are as follows:
are respectively input to the CRT discrimination circuit 27, and the corresponding CRT
The discrimination circuit 27 outputs a selector control signal a, a selector control signal b, a coordinate detection period signal AI, a CRT discrimination signal f, and a latch timing pulse h. Of these, the coordinate detection period signal AI
is input to the coordinate detection circuit 25. The selector control signal a is outputted at the timing shown in FIG. 4, inputted to the selector 23, and during the signal period, the data circuit outputs the data from the storage device A3 as dark data DDA corresponding to a dark image. control to switch to the 21 side. Similarly, the selector control signal b is output at the timing shown in FIG. 4, inputted to the selector 24, and during the signal period, data from the storage device B4 is converted into dark data DDA from the data circuit 21 corresponding to a dark image. control to switch. As a result, a bright line detection signal l input to the CRT discrimination circuit 27 is obtained as shown in FIG. 4, and a CRT discrimination signal f is obtained based on the timing at which this bright line is detected. This discrimination signal f is
The data is input to the write data control circuit 11, and thereafter data is selectively written to the storage device A3 or the storage device B4.
It becomes possible to write. Data is written to each storage device 3, 4 after the CRT determination period d ends.
It becomes possible. The latch 10 registers the address counter 2 at the rising edge of the latch timing pulse h shown in FIG.
By latching the output of , the indicated coordinates of the light pen 9 are detected, and the write data control circuit 11
Determine the coordinates indicated by the light pen and store the coordinates in the storage device A.
3 or controls data writing to the storage device B4. Next, an example of the CRT discrimination circuit 27 is shown in FIG. 3, and its operation will be explained with reference to FIGS. 4 and 5. The light pen switch signal SW is converted by the shift register 31 into pulses γ ₁ , γ ₂ , γ ₃ , and γ ₄ synchronized with the vertical synchronizing signal V. The shift register outputs γ ₁ and γ ₂ are input to the gate 32 to obtain a coordinate detection period signal AI. Similarly, γ ₂ , γ ₃ and the area sampling pulse AR are each input to the gate 33 to obtain the selector control signal a. Similarly, γ ₃ , γ ₄ and the area sampling pulse AR are each input to the gate 34 to obtain the selector control signal b. Similarly, γ ₂ , ₃ , γ ₄ are gate 35
The CRT discrimination period signal d, which is the output of the gate 35, is input to the counter 37 and the gate 38. The counter 37 counts the vertical synchronizing signal V during the CRT discrimination period d, and inputs the output signal g to the latch 41. On the other hand, said
The CRT discrimination period d and the bright line detection signal l are input to the gate 38, which outputs the signal m, which sets the reset flip-flop 40 and obtains the signal P. The signal P is input to the latch 41, and at its rising edge, the output signal g of the counter 37 mentioned above is latched to obtain the CRT discrimination signal f.
Figure 4 shows the signals l _A , m _A , P _A , f _A obtained when the light pen 9 indicates the CRT/A7, and the signals l _B , obtained when the light pen 9 indicates the CRT/B8.
m _B , P _B , f _B are shown, and FIG. 5 shows an enlarged view of the area indicated by the circle in FIG. 4. As is clear from this, it is clear that the light pen switch signal SW
turns on, and from the fourth field onward, the aforementioned signal f _A becomes (L level), and f _B becomes (H level).
It is becoming. Therefore, the output f of latch 41 is
This becomes a CRT discrimination signal and is input to the write data control circuit 11 shown in FIG. Also, the shift register 31
The output signal γ ₁ is input to the rising edge detection circuit 36 to obtain a signal e, which resets the counter 37, reset flip-flop 40, and latch 41, respectively. Next, the bright line detection signal l and the output signal γ ₄ of the shift register 31 are inputted to the gate 39 to obtain the signal q, which is inputted to the reset flip-flop 42 to obtain the signal h. The signal h becomes a latch timing signal that controls latch 10 of FIG. However, the reset flip-flop 42 is reset every field by the vertical synchronizing signal V.

The CRT discrimination circuit 27 is configured as described above, and FIG. 4 shows that the light pen 9 is CRT/A7,
It shows waveform diagrams at various locations in FIG. 3 when each of the CRT and B8 is instructed. Based on the CRT discrimination signal f thus obtained, the write data control circuit 11 can selectively access the storage device A3 or the storage device B4. Furthermore, the 6th
The figure shows an example of the display period corresponding to selector control signal a or b.
Therefore, there is a range B in which dark data DDA is displayed.

In the above explanation, we are talking about how to distinguish between two CRTs, but if there are three or more CRTs,
Also for CRT, the CRT discrimination period signal d is set to 3 fields or more and the brightness is not suppressed during that period.
This can be easily determined by sequentially switching the bright line detection timing and monitoring the bright line detection timing.

As explained above, according to the present invention, it is possible to automatically determine which of multiple CRTs the light pen is pointing to, without requiring the operation of an external changeover switch, etc.
The operability of the CRT display device can be improved. Also,
The display of dark image data for CRT identification is only a small part of the CRT screen;
Since the CRT display screen remains displayed without disappearing, there is no risk of it becoming inconvenient to use or causing flickering or flashing that would cause operator eyestrain.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the existing device, FIG. 2 is a block diagram showing the internal configuration of the device of the present invention,
Figure 3 is a block diagram showing the configuration of the main parts, Figure 4
The figure is a waveform diagram for explaining the operation of Figure 3, Figure 5 is an enlarged waveform diagram of the main part of Figure 4, and Figure 6 is a pattern diagram showing the display surface of a CRT. A storage device, 7 and 8 a CRT, 9 a light pen, 11 a write data control circuit, and 27 a CRT discrimination circuit, respectively.

Claims (1)

[Claims] 1 Displays image data stored in multiple storage devices on multiple CRTs driven by the same synchronization signal, and detects bright lines at the designated location by pointing the CRT screen with a light pen. In a CRT display device, which determines the coordinate position and rewrites the image data in the storage device corresponding to the coordinate position, the coordinates are obtained based on the bright line of the CRT detected when the light pen touches the CRT screen. means for extracting an area around the contact point from the area; means for switching and displaying dark image data provided separately from the image data in the memory in the area near the extracted light pen indicated coordinates; and a means for sequentially switching the CRT to be switched and displayed at a cycle longer than the vertical scanning cycle, and detecting and identifying the CRT indicated by the light pen by monitoring the timing of the bright line detection signal obtained from the light pen. A CRT display device characterized by: