JPH1141614A - Purity correction circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a purity correction circuit by which display quality is enhanced by keeping color purity of an image on a screen of a CRT high at all times, the entire man-hours is reduced, the complicated circuit is avoided, the productivity is improved and the production cost is reduced. SOLUTION: The circuit is provided with a 2-pole coil 1 that generates a bipolar magnetic field at a CRT neck part, a face correction waveform generating circuit 2, a controller 4 that allows a landing measurement device 8 to read a landing error on a real screen externally and controls the face correction waveform generating circuit 2 for correcting its error and generating a corrected waveform to cancel it, an amplifier circuit 3 to drive the 2-pole coil 1 and a detection circuit that detects a change in an external environment such as ambient temperature and earth magnetism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a purity correction circuit for correcting a beam landing error in a color CRT such as a display monitor.

[0002]

2. Description of the Related Art Conventionally, in a cathode ray tube (hereinafter abbreviated as CRT) for a color used in a display color monitor or a color television of an OA device, an electron beam (hereinafter simply referred to as a beam) on a display screen thereof has been used. Purity correction circuits are widely used to correct a landing error, that is, a beam landing error.

A beam landing error is a color C
In RT, for example, a beam that originally hits a green phosphor (a beam for green) always emits only the green phosphor by hitting only the green phosphor in any state, and is displayed. The screen needs to be colored green. However, due to variations in the landing adjustment of the CRT and the influence of the external environment such as environmental temperature and geomagnetism, a green beam is sometimes displayed on the display screen G1 as shown in FIG. For example, slightly hitting a blue phosphor. This phenomenon is caused by the display screen G1 of the color CRT.
Randomly occurs at any position.

An outline of a conventional purity correction circuit for correcting such a beam landing error will be described below. FIG. 3 is a configuration diagram schematically showing a conventional purity correction circuit. In this purity correction circuit, as shown in FIG. 3, functionally identical correction coils B1, B2, B3, and B4 are arranged in the periphery of the rear surface of the funnel of the CRT 30 where a landing error is likely to occur. The correction coils B1 to B4 have a DA converter 32 according to a control signal from the control circuit 31.
Are supplied individually through the output amplifier 33, and the correction coils B1 to B4 generate a magnetic field that cancels a beam landing error with respect to the peripheral portion of the CRT 30, respectively, by the DC current.
It is configured to correct a beam landing error.

As described above, in a color CRT, a beam landing error is corrected by the purity correction circuit.

[0006]

However, in the conventional purity correction circuit for correcting the beam landing error as described above, the beam on the display screen G1 depends on the size and shape of the correction coils B1 to B4 attached to the rear surface of the funnel of the CRT 30. Since the effect of correcting the landing error is affected, for each CRT 30,
Knowing in advance the degree of each beam landing error and the tendency of deviation, depending on the situation,
If there is a problem that the correction coils B1 to B4 need to be set to an optimum size and shape, or if there is a locally large beam landing error in the correction magnetic field generated by the correction coils B1 to B4, it is sufficient. There was a performance problem that the correction could not be made.

For this reason, the design work of the correction coils B1 to B4 is extremely troublesome, and it is necessary to select and install the optimum correction coil for each CRT 30, and to select the correction coil which locally generates a large correction magnetic field. It is necessary to mount the correction coil at a large scale, so that the overall man-hour is increased due to the large size of the mounting of the correction coil, and the correction of the large beam landing error generated locally is insufficient. There was a problem that the display quality on the display screen G1 was reduced.

In addition, circuits such as an output amplifier 33 and a DA converter 32, which are configured as drive circuits for the correction coils B1 to B4, are required for each correction coil, and the circuit becomes complicated. .

As described above, there are also problems such as a decrease in productivity and an increase in cost, which occur from the entire process. The present invention solves the above-mentioned conventional problems.
The color purity on the RT display screen can be constantly increased to improve the display quality, and the overall man-hours can be reduced and the circuit can be prevented from becoming complicated, thus improving productivity and reducing costs. A purity correction circuit is provided.

[0010]

According to the present invention, there is provided a purity correction circuit for generating a surface correction waveform based on a CRT-specific beam landing error measured by a measuring device by a control device. Control the circuit,
In response to the beam landing error, a waveform required for the correction is generated, and the two-pole coil is dynamically driven according to the beam scanning. It is characterized by correction.

[0011] Further, based on a function set in advance by the control device in accordance with a change in the external environment and a beam landing error generated thereby, the external environment in the actual use range detected by the detection circuit. The surface correction waveform generation circuit is controlled based on the beam landing error determined from the arbitrary change of the above, and a waveform necessary for the correction is generated for the beam landing error, and the two-pole coil is dynamically moved according to the beam scanning. , The dynamic correction is performed at an arbitrary point on the screen according to the occurrence state of the beam landing error.

As described above, it is possible to improve the display quality by always increasing the color purity on the display screen of the CRT, to reduce the overall man-hour and prevent the circuit from becoming complicated, and to improve the productivity. And cost reduction can be realized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A purity correction circuit according to a first aspect of the present invention is a purity correction circuit for correcting a beam landing error occurring on a display screen of a color CRT.
A two-pole coil provided separately from a two-pole permanent magnet for fixedly correcting both the position and the amount on the display screen of the RT; and the beam landing error is detected by the CRT beam scanning through the two-pole coil. At an arbitrary position on the display screen where the beam has arrived, a surface correction waveform generation circuit that generates a correction waveform such as to correct by an amount according to the state of occurrence of the beam landing error, and for each position where the beam has arrived, A landing measuring instrument for measuring the beam landing error from outside the CRT,
A control device for controlling generation of the correction waveform by the surface correction waveform generation circuit, wherein the control device controls the two-pole coil by the correction waveform based on a beam landing error measured by the landing measuring device. The surface correction waveform generation circuit is configured to be driven so as to be driven.

According to this configuration, the control device controls the surface correction waveform generating circuit based on the beam landing error unique to the CRT measured by the measuring instrument, and the beam landing error is required for the correction. By generating a simple waveform and dynamically driving the two-pole coil in accordance with the beam scanning, dynamic correction is performed at an arbitrary point on the screen in accordance with the state of occurrence of a beam landing error.

According to a second aspect of the present invention, there is provided a purity correction circuit for correcting a beam landing error generated on a display screen of a color CRT.
A two-pole coil provided separately from a two-pole permanent magnet for fixedly correcting both the position and the amount of the beam landing error on the display screen of the CRT; and transmitting the beam landing error through the two-pole coil. C
A surface correction waveform generation circuit for generating a correction waveform for correcting the beam landing error at an arbitrary position on the display screen according to the beam scanning by an amount corresponding to the state of occurrence of the beam landing error; A detection circuit for detecting a change in an external environment condition consisting of temperature and geomagnetism in the surroundings, and a function established between the change in the external environment condition and the beam landing error generated by the detection circuit; A control device for controlling the generation of the correction waveform by a circuit, based on the beam landing error obtained from the change of the external environmental conditions detected by the detection circuit based on the function, The plane correction waveform generation circuit is controlled to drive the two-pole coil with the correction waveform.

According to this configuration, the actual use range detected by the detection circuit is detected by the control device based on a function set in advance in which the external environment change and the beam landing error generated thereby correspond to each other. The surface correction waveform generation circuit is controlled based on a beam landing error determined from an arbitrary change in the external environment in the above, and a waveform necessary for the correction is generated for the beam landing error, and the two-pole coil is beamed. By dynamically driving according to scanning, dynamic correction is performed at an arbitrary point on the screen in accordance with the state of occurrence of a beam landing error.

Hereinafter, a purity correction circuit according to an embodiment of the present invention will be specifically described with reference to the drawings. Here, a color CR using a color CRT is used.
A description will be given by taking as an example a case in which the T display device is used. (Embodiment 1) A purity correction circuit according to Embodiment 1 of the present invention will be described.

FIG. 1 is a configuration diagram of a color CRT display device using the purity correction circuit according to the first embodiment. In FIG. 1, reference numeral 1 denotes a two-pole dynamic coil (hereinafter simply referred to as a two-pole coil), which is a two-pole dynamic coil for statically (fixedly) correcting a beam landing error in position and amount on a display screen 11 of a CRT 10. It is provided separately from the permanent magnet. Reference numeral 2 denotes a surface correction waveform generation circuit, and a display screen 1 of the CRT 10
1 to output a signal waveform that can dynamically (indefinitely vary over a wide range) the beam landing error at an arbitrary position on the display screen 11 where the beam has arrived, by an amount corresponding to the state of occurrence of the beam landing error. I do. Reference numeral 3 denotes an amplifier circuit which amplifies the signal waveform output from the surface correction waveform generation circuit 2 in order to obtain a current sufficient to drive the bipolar coil 1. Reference numeral 4 denotes a control device for controlling the surface correction waveform generation circuit 2. The above is provided inside the color CRT display device 5. Reference numeral 8 denotes a landing measurement device provided outside the color CRT display device 5 to measure a beam landing error unique to the CRT 10 on the display screen 11 from outside the CRT 10.

In the purity correction circuit of the color CRT display device 5 configured as above, the control device 4 controls the beam landing error unique to the CRT 10 measured from outside the color CRT display device 5 by the landing measuring device 8. Is read, and based on the beam landing error, the surface correction waveform generation circuit 2 is controlled to generate a waveform required for the correction for the beam landing error and amplify it by the amplifier circuit 3, and then read the two poles. By dynamically driving the coil 1 in accordance with the beam scanning, the two-pole coil 1 dynamically changes the position and amount (a wide range) at an arbitrary point on the display screen 11 where the beam has arrived, according to the state of occurrence of the beam landing error. Indefinitely over time).

As a result, the display quality can be improved by always increasing the color purity on the display screen 11 of the CRT 10, and the overall man-hours can be reduced and the circuit can be prevented from becoming complicated, thereby improving the productivity. Improvement and cost reduction can be realized. (Embodiment 2) Embodiment 2 of the present invention will be described.

FIG. 2 is a configuration diagram of a color CRT display device using the purity correction circuit according to the second embodiment. In FIG. 2, a two-pole coil 1, a surface correction waveform generation circuit 2, an amplifier circuit 3, and a control device 4 have the same configuration as that of the purity correction circuit of the first embodiment. And a geomagnetic sensor 6 which is a detection circuit for detecting a change in the geomagnetism around the CRT 10. The temperature sensor 7 is a detection circuit for detecting the temperature of the CRT 10. Various signals are taken into the control device 4 as change data of external environmental conditions.

On the other hand, the control device 4 is provided with the influence of the external environment on the beam as a function in advance.
The control device 4 controls the CRT 10 according to changes in the external environment.
The surface correction waveform generation circuit 2 is configured to output a surface correction waveform that corrects and cancels the beam landing error generated on the display screen 11 of FIG.

In the purity correction circuit of the color CRT display device 5 configured as described above, the control device 4 is set in advance in such a manner as to correspond to the external environment change and the beam landing error generated thereby. The temperature sensor 7 and the geomagnetic sensor 6
The surface correction waveform generation circuit 2 is controlled based on a beam landing error determined from an arbitrary change in the external environment in an actual use range detected by a detection circuit such as a detection circuit, and the beam landing error is corrected. After the necessary waveform is generated and amplified by the amplifier circuit 3, the bipolar coil 1 is dynamically driven in accordance with the beam scanning, so that the beam landing error can occur at an arbitrary point on the display screen 11 where the beam has arrived. Depending on,
Both the position and the amount are dynamically corrected (irregularly over a wide range) by the two-pole coil 1.

As a result, as in the case of the purity correction circuit of the first embodiment, the color purity on the display screen 11 of the CRT 10 can be constantly increased to improve the display quality, and the overall man-hour can be reduced. It is possible to reduce the number of circuits and prevent the circuit from becoming complicated, thereby improving the productivity and reducing the cost.

[0025]

As described above, according to the present invention, the control device controls the surface correction waveform generation circuit based on the CRT-specific beam landing error measured by the measuring instrument, and the On the other hand, by generating a waveform necessary for the correction and dynamically driving the two-pole coil in accordance with the beam scanning, it is possible to dynamically correct at an arbitrary point on the screen according to the state of occurrence of a beam landing error. .

Further, the control device controls the external environment in the actual use range detected by the detection circuit based on a function set in advance, in which the external environment change and the beam landing error generated thereby correspond to each other. The surface correction waveform generation circuit is controlled based on the beam landing error determined from the arbitrary change of the above, and a waveform necessary for the correction is generated for the beam landing error, and the two-pole coil is dynamically moved according to the beam scanning. , It is possible to perform dynamic correction at an arbitrary point on the screen according to the occurrence state of the beam landing error.

Therefore, the display quality of the display screen of the CRT can be improved by always increasing the color purity, and the overall man-hour can be reduced and the circuit can be prevented from becoming complicated, thereby improving the productivity. Cost reduction can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a purity correction circuit according to a first embodiment of the present invention;

FIG. 2 is a configuration diagram of a purity correction circuit according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional purity correction circuit.

FIG. 4 is an explanatory diagram of a landing error in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 2-pole coil 2 Surface correction waveform generation circuit 3 Amplifier circuit 4 Control device 6 Geomagnetic sensor 7 Temperature sensor 8 Landing measuring instrument

Claims (2)

[Claims] 1. A purity correction circuit for correcting a beam landing error occurring on a display screen of a color CRT, wherein the beam landing error is detected by the CRT.
A two-pole coil provided separately from a two-pole permanent magnet for fixedly correcting both the position and the amount of the beam on the display screen, and the beam landing error is transmitted through the two-pole coil according to the beam scanning of the CRT. At an arbitrary position on the display screen where the beam has arrived, a surface correction waveform generation circuit that generates a correction waveform that corrects by an amount according to the state of occurrence of the beam landing error, and for each position where the beam has arrived, Beam landing error C
A landing measurement device for measuring from outside the RT, and a control device for controlling generation of the correction waveform by the surface correction waveform generation circuit, wherein the control device is configured to control the control device based on a beam landing error measured by the landing measurement device. A purity correction circuit configured to control the surface correction waveform generation circuit to drive the two-pole coil with the correction waveform. 2. A purity correction circuit for correcting a beam landing error occurring on a display screen of a color CRT, wherein the beam landing error is detected by the CRT.
A two-pole coil provided separately from a two-pole permanent magnet for fixedly correcting both the position and the amount of the beam on the display screen, and the beam landing error is transmitted through the two-pole coil according to the beam scanning of the CRT. And a surface correction waveform generation circuit for generating a correction waveform for correcting at an arbitrary position on the display screen by an amount corresponding to the state of occurrence of the beam landing error, and a temperature and geomagnetism around the CRT. A detection circuit for detecting a change in an external environment condition, and a function established between the change in the external environment condition and the beam landing error generated by the detection circuit, and generation of the correction waveform by the surface correction waveform generation circuit And a control device for controlling the control device, the control device, the detection circuit has been detected by the detection circuit based on the function Based on the beam landing error resulting from the change parts environmental conditions, the correction waveform by a purity correction circuit configured to control the surface correction waveform generating circuit to drive the 2-pole coil.