JPH04198982A - Crt display device - Google Patents

Abstract

PURPOSE:To form the CRT display device which is not affected by external magnetic fields by controlling a horizontal means and vertical means to correct the distortion of an electron beam in accordance with the external magnetic field value in a screen part. CONSTITUTION:A magnetic field detecting sensor 10 as a magnetic field detecting means, a horizontal component measuring circuit 11 and vertical component measuring circuit 12 connected to this magnetic field detecting sensor 10 are provided above the screen part of the CRT. The magnetic detecting sensor 10 detects the external magnetic fields in the screen part and outputs the external magnetic field value. On the other hand, a correcting means controls the horizontal means 6 and the vertical means 7 to control the distortion of the electron beam in accordance with this external magnetic field value. The CRT display device which obviates the generation of the distortion in the display of the screen part by the external magnetic fields is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a CRT display device, and more specifically to a CRT display device.
The present invention relates to a method for controlling a deflection yoke of an RT display device.

[Prior Art] A conventional CRT display device is a CRT that has a screen section equipped with a phosphor screen that receives electron beams emitted from an electron gun that has a built-in grid and converging lens system inside a glass tube.
and a deflection yoke portion that is provided around the travel path of these electron beams and deflects the electron beams horizontally and vertically, respectively.

The deflection yoke section deflected the electron beam horizontally and vertically using a magnetic field generated by sawtooth currents corresponding to the input horizontal and vertical signals, thereby displaying various characters and figures.

[Problems to be Solved by the Invention] However, conventional CRT display devices have a problem in that images displayed on a fluorescent screen are disturbed due to changes in the earth's magnetism and the influence of other devices that generate magnetic fields.

Accordingly, one technical object of the present invention is to provide a CRT display device in which the display screen on a fluorescent screen is not disturbed even if it is affected by changes in the earth's magnetism or by other equipment that generates a magnetic field.

[Means for Solving the Problems] According to the present invention, a C having a screen portion that receives an electron beam.
In a CRT display device having an RT, horizontal deflection means for horizontally deflecting the electron beam, and vertical deflection means for vertically deflecting the electron beam, an external magnetic field in the screen portion is detected and an external magnetic field value is determined. magnetic detection means that outputs.

There is obtained a CRT display device characterized in that it comprises a correction means for correcting distortion of the electron beam by controlling the horizontal means and the vertical means based on the external magnetic field value.

According to the present invention, in the CRT display device, the magnetic sensor detects a horizontal component and a vertical component of the external magnetic field, respectively.

According to the present invention, in the CRT display device, the correction means includes a horizontal deflection correction means for controlling the horizontal deflection means based on a horizontal distortion correction value from the magnetic detection means, and a horizontal deflection correction means for controlling the horizontal deflection means based on the horizontal distortion correction value from the magnetic detection means. and a vertical deflection correction means for controlling the vertical deflection means based on a vertical distortion correction value of the CRT display device.

[Production use] In the CRT display device of the present invention.

A CRT has a screen portion that receives electron beams.

The horizontal deflection means deflects the electron beam horizontally. Further, the vertical deflection means vertically deflects the electron beam. Further, the magnetic detection means detects an external magnetic field in the screen portion and outputs an external magnetic field value.

On the other hand, the correction means corrects the distortion of the electron beam by controlling the horizontal means and the vertical means based on the external magnetic field value.

Therefore, distortion of the display on the screen section does not occur due to external magnetic fields.

Embodiment FIG. 1 is a block diagram of a CRT display device in an embodiment of the present invention. The CRT display device shown in this example includes a CRTI that has a screen section equipped with a phosphor screen that receives an electron beam emitted from an electron gun that includes a grid and a converging lens system inside a glass tube, a horizontal timing generation circuit 8, and a horizontal timing generation circuit 8. The deflection yoke 2. and 3 to generate an electric field or a magnetic field, thereby deflecting the electron beam emitted from the electron gun horizontally and vertically, respectively.A horizontal deflection circuit 4 and a vertical deflection circuit 5
It is equipped with The above configuration has the same structure as the conventional one.

A CRT display device according to an embodiment of the present invention includes a CRT display device according to an embodiment of the present invention.
A magnetic field detection sensor 1 is installed above the screen of the T as a magnetic field detection means.
0, a horizontal component measuring circuit 11 connected to the magnetic field detection sensor 10, and a vertical component measuring circuit 12 are provided.

FIG. 2 is a diagram showing the waveform of an external magnetic field applied to the CRT according to the embodiment of the present invention, and FIG. 3 is a diagram showing the waveform of the external magnetic field applied to the CRT according to the embodiment of the present invention, and FIG. FIG. 4 is a diagram showing the side waves generated from the horizontal timing circuit, and FIG. 5 is a diagram showing the waveform of the composite current output from the horizontal correction circuit.

The magnetic field detection sensor 10 receives an electric signal fDV as shown in FIG.
and fDH are output to the horizontal component measurement circuit 11 and the vertical component measurement circuit 12, respectively.

The horizontal component measurement circuit 11 calculates a horizontal distortion correction value from the horizontal component value of the external magnetic field, and applies the horizontal distortion correction value to the horizontal correction circuit 6 provided between the horizontal deflection circuit 4 and the horizontal timing generation circuit as shown in FIG. A horizontal distortion correction value signal fCH consisting of a correction current α is output. - On the other hand, the vertical component measuring circuit 12 also calculates a vertical distortion correction value from the vertical component value of the external magnetic field in the same manner as the horizontal component measuring circuit, and uses a vertical correction value provided between the vertical deflection circuit 4 and the horizontal timing generation circuit. A vertical distortion correction value signal f is supplied to the circuit 6. Outputs V.

The horizontal component correction circuit 6 receives a horizontal distortion correction value signal f. The horizontal timing signal fTH by the side wave from the horizontal timing generation circuit 8 shown in FIG. 4 and the horizontal distortion correction current α shown in FIG.
A horizontal correction signal fTH2 as shown by 2 is output to the horizontal deflection circuit 4.

On the other hand, the vertical component correction circuit 7 similarly receives the horizontal distortion correction value signal fCV, and generates a horizontal correction signal fTV2 in which the vertical timing signal fTV consisting of the side waves from the vertical timing generation circuit 8 and the vertical distortion correction current are combined. Vertical deflection circuit 5
Output to.

The horizontal correction signal fTH2 input to the horizontal deflection circuit 4 is combined with a video signal (not shown) to output a horizontal deflection signal fH, which drives the horizontal deflection yoke 3.

On the other hand, the vertical correction signal f T input to the vertical deflection circuit 5
A horizontal deflection signal f is obtained by combining V2 and a video signal (not shown).
v to drive the vertical deflection yoke 2.

Therefore, the horizontal and vertical distortions of the electron beam are corrected, and the screen section displays an image without distortion.

[Effects of the Invention] As explained above, according to the present invention, since the magnetic detection means and the correction means are provided, C.
An RT display device can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a CRT display device according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of the waveform of an external magnetic field received by the CRT device, and FIG. 3 is a diagram showing an example of the waveform of an external magnetic field received by the magnetic sensor in FIG. A diagram showing the output waveform from the corresponding horizontal component $1 constant circuit, FIG. 4 is a diagram showing the side waves generated from the horizontal timing generation circuit, and FIG. 5 is a diagram showing the waveform of the composite current output from the horizontal correction circuit. It is. In the figure, 1...CRT, 2...Horizontal deflection plate, 3...
Vertical deflection plate, 4...Horizontal deflection circuit 15...Vertical deflection circuit. 6...Horizontal correction circuit, 7...Vertical correction circuit, 8...
- Horizontal timing generation circuit, 9... Vertical timing generation circuit, 10... Magnetic field sensor, 11... Horizontal component measurement circuit. 12... Vertical component measurement circuit. Figure 1

Claims (1)

[Claims] 1. A CRT having a screen portion that receives an electron beam, horizontal deflection means for horizontally deflecting the electron beam, and vertical deflection means for vertically deflecting the electron beam.
In the display device, magnetic detection means detects an external magnetic field in the screen section and outputs an external magnetic field value, and controls the horizontal means and the vertical means based on the external magnetic field value to detect the electron beam. A CRT display device comprising a correction means for correcting distortion. 2. The CRT display device according to claim 1, wherein the magnetic sensor detects a horizontal component and a vertical component of the external magnetic field, respectively. 3. In the CRT display device according to claim 2, the correction means includes horizontal deflection correction means for controlling the horizontal deflection means based on the horizontal distortion correction value from the magnetic detection means; and vertical deflection correction means for controlling said vertical deflection means based on a vertical distortion correction value of said CRT display device.