JPS6344859Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a screen position adjustment device suitable for use in a CRT display device.

Recently, personal computers have come into use in various fields, and CRT display devices are often used as output display devices for these computers.

By the way, since the content of the output signal differs from computer to computer, it is necessary to adjust the horizontal and vertical screen positions, screen size, etc. on the CRT display device side to match the target computer.

<Prior Art> Conventionally, this type of CRT display device has been provided with horizontal and vertical screen position adjustment devices. In this case, the horizontal screen position adjustment device can be constructed relatively easily by inserting a variable resistor into the horizontal deflection circuit. However, in the case of a vertical screen position adjustment device, a large variable resistor is required in the vertical deflection circuit, so such a variable resistor is usually not used.
The resistance constant was changed by replacing the chip terminals.

<Problem> Therefore, in conventional CRT display devices, it is difficult to adjust the vertical screen position from the outside, and it is necessary to perform adjustment operations with the back cover open, which is extremely troublesome.

<Solution Means> The present invention has been devised in view of the above points, and provides a screen position adjustment device that allows external adjustment using an up-down counter.

<Example> The following describes an example of the present invention shown in the drawings. In the drawing, 1 is a normal vertical deflection circuit including a series circuit of a vertical deflection coil, a capacitor 1c, and a resistor 1r. Further, 2 is a clock pulse generator, 3 is an up-down counter, 4a is a count-up switch, and 4b is a count-down switch.
Each time a clock pulse is supplied, the counter 3 is counted up, and conversely, while the countdown switch 4b is turned on, the counter 3 is counted down. 5 is a decoder that converts the count output of the counter 3 into outputs from 1 to 10.

Furthermore, here, the output terminals of the decoder 5 are commonly connected via resistors R ₁ to R ₁₀ , respectively, and this common terminal is connected to one end of the vertical deflection coil 1 l and connected to the positive power supply terminal +B ₁ via a resistor R ₀ . It is connected to the. It is assumed here that the values of the resistors R ₁ to _{R 10} are set in the relationship R ₁ <R ₂ <R ₃ . . . < R ₉ <R ₁₀ .

In the steady state of the vertical screen position adjustment device configured as described above, the up-down counter 3
is maintained at a constant count output state, and at this time, the decoder 5 outputs an output L to a specific output terminal, for example, an output terminal according to the output of the counter 3. Therefore, in this case, the DC voltage E ₁ divided by the resistor R ₀ and the resistor R ₅ , that is, E ₁ =R ₅ B ₁ /R ₀ +R ₅ , is superimposed on the vertical deflection current flowing through the vertical deflection coil 1l. is applied. As a result, the center of the raster is displayed on the CRT screen at a vertical position determined by the DC voltage _E1 .

Now, install the above CRT display device 1.
If the output image displayed on the CRT screen is shifted toward the bottom of the screen when two computers are combined as an output display device, turn on the count-up switch 4a while looking at the screen, and the up-down counter 3 Then, each time a clock pulse is supplied from the clock pulse generator 2, the count is incremented by 1, and at this time, the decoder 5 switches the output from the output end to the output end, etc., and superimposes it on the vertical deflection coil 1l accordingly. The DC voltage is gradually reduced as follows: E ₂ = R ₆ B ₁ /R ₀ +R ₆ , E ₃ =R ₇ B ₁ /R ₀ +R ₇ , E ₄ . As a result, the raster center on the CRT screen is moved upward little by little, and the computer output image is also moved upward accordingly. Then, when this output image reaches the center of the desired CRT screen, turn on the count-up switch 4a.
If you turn off the up-down counter 3, the count contents of up-down counter 3 will be maintained at that time and will not be used from now on.
The vertical image position on the CRT screen is stopped at the desired position.

On the other hand, if the output image displayed on the CRT screen is biased toward the top of the screen, turning on the countdown switch 4b causes the up-down counter 3 to count down by 1 each time a clock pulse is supplied. When the output of the decoder 5 is sequentially switched to...
Accordingly, the DC voltage superimposed on the vertical deflection coil 1l is gradually increased. Result like this CRT
The raster center on the screen is moved downward little by little, and the computer output image is also moved downward accordingly. When the output image reaches the desired center position on the CRT screen, the countdown switch 4b is turned off, and the vertical image position on the CRT screen is thereafter stopped at the desired position.

In the above embodiments, the case where the present invention is applied to a vertical screen position adjusting device has been described, but the present invention can of course be applied to a horizontal screen position adjusting device if necessary.

<Effects> As described above, according to the screen position adjustment device of the present invention, the DC voltage superimposed on the deflection coil can be changed by selectively switching a plurality of resistors according to the output contents of the up-down counter using the up-down counter. Since the screen position displayed on the CRT screen is moved by the CRT display device, the screen position can be easily adjusted from the outside by simply attaching a count-up switch and a count-down switch to the outside of the CRT display device. be able to.

[Brief explanation of the drawing]

The drawing is a circuit diagram of one embodiment of the present invention. 3...Up-down counter, 4a...Count-up switch, 4b...Countdown switch, 5...Decoder, 1l...Vertical deflection coil, _R1 to _R10 ...Resistance.

Claims (1)

[Scope of utility model registration request] In a CRT display device, an up-down counter whose counting contents can be changed by an externally attached switch, a means for selectively switching a plurality of resistors according to the counting contents of the counter, and a means for selectively switching a plurality of resistors according to the counting contents of the counter, and a 1. A screen position adjustment device comprising: means for applying mutually different DC voltages to a deflection coil in a superimposed manner, and the screen position on a CRT screen can be adjusted from the outside using the switch.