JPS6010628B2 - Color character display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color character display device, particularly a display device that uses a scan converter tube and a color memory to switch the output signal of the scan converter tube to display color characters. This invention relates to a color character display device that corrects color shift.

Conventionally, color display devices that use a scan converter tube (hereinafter referred to as SCT) as a refresh memory to display characters or graphics in color have developed a method of writing color information by dividing the screen and using multiple SCTs to achieve colorization. This method is known, as well as a method in which the writing level to the SCT is modulated in amplitude depending on the color, and the writing level is demodulated in amplitude at the time of writing to create color. A specific example of this is a display in which the display screen is divided into small sections as shown in Figure 1, and the SCT readout signal is colored and displayed using a color memory that stores a color code corresponding to each small section. Show the device.

In Figure 1, there is one computer (CPU) and 20 memories.
Character codes and display addresses are extracted from the character code memory (CCM) 21 and display address memory (DAM) 22 of
/F) Output via 30. At the same time, the color code is also extracted from the character code and written into the color memory 50. The output 101 of the font memory 40 is written as a character pattern at the previously designated display address position of the SCT 60. When the above-described operation is completed after all the character codes for one screen have been retrieved from the character code memory 21, the computer 10 switches the SCT 60 to a reading state. SCT6
The readout of 0 is timed by the control signal of the color CRT 80, and the readout signal 101 of the SCT 60 is read out in synchronization with the display.The color code signal 10 of the color memory 50 is read out in synchronization with the display. It is connected to one of the electron gun inputs 102 of the corresponding color of a color CRT such as , and a color display is performed. In this method, the color memory 50 and the SCT 60 are controlled by essentially different operations, that is, digital and analog operations, so color shift due to deflection nonlinearity of the deflection circuit of the SCT 60, and writing and reading of the SCT are controlled. Color shift due to temperature changes in deflection becomes a problem.

In addition, the accuracy of deflection regarding color shift is normally determined by the number of display digits: 32.
If the permissible value for character/line and display color deviation is 5% per character, a fairly strict value of 0.16% is required.

SUMMARY OF THE INVENTION An object of the present invention is to facilitate correction of color shift by SCT in a color character display device having the above-described configuration of color memory and SCT.

That is, the present invention corrects the deflection nonlinearity of the SCT by adding a correction address together with the character display address, and detects the SCT internal temperature and outputs the corrected display address after temperature correction. This is a correction. The details will be explained below with reference to the drawings.

FIG. 2 shows an embodiment of the invention. The basic configuration is the same as that in FIG. 1, but the correction display address memory 22
0, a temperature detector 200, an A/D converter 210, and a timer 250 are added. Note that elements common to those in FIG. 1 are given the same reference numerals. First, correction of color shift due to deflection distortion and deflection nonlinearity of the SCT 60 will be explained.

Character code memory 21 of memory 20 and display address 22
The color-coded character code and display address imported into the computer 10 from and are sent to the interface circuit 30.
The font memory 40, color memory 50 and S
The output power of the font memory 40 is written into the SCT 60' according to the display address. The actual writing position of the character pattern written on the SCT 60 in this manner deviates from the scheduled writing position corresponding to the normal display address due to distortion and non-linearity of the writing deflection system of the SCT 60. Furthermore, when the SCT 60 switches from the write mode to the read mode, reading is performed by scanning the entire surface of the target of the SCT 60 in synchronization with the scanning system of the color CRT. will no longer match what is written. On the other hand, the color memory 50 is read out using the color CRT 80.
Because this is done at precise timing in synchronization with the scanning system of the SCT 60, color misalignment occurs between the character pattern and the readout character pattern of the SCT 60.
Correction display address memory (DS) with an address attached to this
As shown in FIG. 3, AM) 220 includes a memory (DSAX) 221 for storing correction display addresses in the x direction and a memory (DSAY) 2 for storing correction display addresses in the Y direction.
Consists of 22. FIG. 4 shows a color CRT display screen 230 and memories 221 and 2 for storing correction display addresses.
22 is shown. In addition, here, any one of L to L shown in the t memories 221 and 222 is selected by temperature detection, and it is sufficient to consider any one of them. In this example, the unit cell 231 corresponds to the color code '2'.
One character is displayed in the ×2 unit cell 232. FIG. 5 shows the value of the corrected display address as the amount of deviation from the display address.

From the curve 240 showing the color shift from the 2×2 unit cell 232 displayed on the color CRT 80, the amount of shift for color shift correction “in other words, it shows the correction value △, ~△4. This correction value △, ~△ 4 can be displayed in a checkered pattern on the color CRT 80, and from the entry switch of the calculator 10, the correction display address memory 22 can be set independently for the X and Y directions. The orthogonality of the deflection coils must be corrected to ensure that they are exactly orthogonal to X-Y.Next, we will explain the correction of color shift due to the temperature characteristics of the SCT60. Temperature drift is so great that color shift cannot be ignored.In order to suppress this temperature drift to the deflection position accuracy described above over a wide range, it is not enough to improve the temperature characteristics of the deflection system circuit.SCT60's cooling fan Temperature detector 20 installed at the exhaust port of 61
0 detects the average temperature inside the SCT 60, the detected temperature is converted from analog to digital by the A/D converter 210, and its output is read into the computer by the timer 2501 at fixed time intervals. In FIG. 4, the correction display address memory (DSAX) 221 and DSAY22
2 shows a case where the operating temperature range of the color display device is equally divided into LT4 and has corrected display address values at each temperature. That is, the computer 10 uses the A/○ converter 210
One of the corrected display addresses (T to T4) closest to the temperature read from is sent to the SCT 60, and characters are written at the optimal position for each detected temperature. This makes it possible to correct not only the color shift caused by the deflection distortion and deflection nonlinearity of the SCT 60, but also the color shift caused by its temperature characteristics. As described above, the present invention provides a specific configuration of a novel device for correcting color shift in a character color display device in which the color memory operates digitally and the scan conversion tube operates analogously.
In advance, the deviation or correction amount from the normal display device at each writing position at each temperature is determined and an address is given, and the address character pattern display position is determined by specifying the correction address while measuring the temperature when the device is driven. This is an easy correction.

This makes it possible to compensate for color shifts in color display of character patterns very easily.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a subordinate color character display device, FIG. 2 is a configuration diagram of a color character display device according to an embodiment of the present invention, and FIG.
The figure is a layout diagram of some of the components in Figure 2, Figures 4 and 5.
The figure is an explanatory diagram of FIG. 2. 10...CPU, 20...Memory, 21...
Character code memory, 22...Display address, 2
20. ...Correction display address memory, 30...
・Interface, 40... Font memory, 50...
...Color memory, 60...Scan conversion tube, 61.
... Cooling fan, 200 ... Temperature detector, 210 ... Analog-digital converter, 2
20...Correction display address memory, 230...
...Color CRT display screen, 250'' timer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1 Temporarily store the character pattern signal read from the character generator in the scan exchange tube according to the write position address, store the display color code in the color memory, and perform the scan conversion according to the display color code. A device for colorizing and displaying a tube readout signal includes a temperature detector for detecting the temperature of the scan conversion tube, and an A/D converter for the output of the temperature detector.
a converter for converting, a correction display address memory provided with an address for a deviation from a normal display position or a correction amount to a normal display position at each writing position at each temperature, and a correction display address memory for the output of the A/D converter. 1. A color character display device, comprising means for controlling a character writing position on said scan exchange tube based on the output of said corrected display address memory selected accordingly.