KR20010081178A - Mutiplex division beam index color cathode ray tube - Google Patents

Abstract

PURPOSE: A multiple partitioning beam index color cathode ray tube is provided to address the problem of a beam tilt and a beam size by dividing a picture to reduce the distance between an electron gun and a screen. CONSTITUTION: A focusing unit(60) excites an electron beam being scanned on an index stripe from a plurality of electron guns. A photo-detector(61) detects a focused beam index at the focusing unit(60). A band pass filter(62) passes a frequency with a predetermined band for the detected beam index from the photo-detector(61). A limiter limites the frequency from the band pass filter(62). A phase locked loop synchronizes the phase of the limited frequency by the limiter. A ring counter counts a synchronized index signal from the phase locked loop. An index signal processing unit(600) is made of a color signal switching unit, which outputs a color signal based on the synchronized index signal counted at the ring counter. An amplifier amplifies the color signal from the index signal processing unit(600) to provide the same to an electron gun. A controller(68) calculates at a predetermined period the cathode current and voltage of each partitioned area to control an amplification coefficient. A memory unit(69) stores the peak value of the index beam adjusted by the controller(68) and the cathode current and voltage.

Description

Multi-Split Beam Index Color Cathode Ray Tube {MUTIPLEX DIVISION BEAM INDEX COLOR CATHODE RAY TUBE}

The present invention relates to a multi-segment beam index color cathode ray tube, and more particularly, to maintain the same brightness on a subdivided screen in a large high-definition beam index color cathode ray tube composed of a plurality of small deflection portions and an electron gun. A multi-segment beam index color cathode ray tube.

The color cathode ray tube which is generally used has many advantages due to its low price and relatively clear image quality.However, due to the shadow mask that performs color screening, the color cathodic ray tube causes thermal expansion and degrades color purity in the case of high current region and image size. Since the electron beam is affected by the geomagnetic field, it shields the geomagnetic field with the inner shield inside the color cathode ray tube, and also requires a degaussing circuit and a coil in the television set. Have.

Therefore, in order to solve the problem of the color CRT, a shadow index tube without shadow mask and inner shield was developed.

That is, the beam index color cathode ray tube does not have a shadow mask having a color discrimination function and an inner shield for shielding the geomagnetic field, and as illustrated in FIG. 1, the light collecting plate 1 and the light detecting unit may detect the ultraviolet rays emitted from the index stripe and the index stripe. 2), the beam index cathode ray tube detects an index signal excited by an electron beam irradiated from the single electron gun 3 by the photodetector 2, and the detected signal is transmitted to a driving circuit (not shown). By synchronizing with the color signal, the position of the electron beam is always configured to drive a desired color. In the figure, reference numeral 4 denotes a deflection coil.

Unlike the shadow mask type color cathode ray tube, the beam index color cathode ray tube uses a single electron gun (single electron gun), so that the misconvergence (MICONVERGENCE) of the deviation of the color signal (R, G, B) electron beam is "0". Since there is no shadow mask, it has a great advantage such as no unnecessary moire and doming phenomenon.

However, the beam index color cathode ray tube is limited in electron beam size, unlike a conventional shadow mask color cathode ray tube in view of driving principle.

That is, as shown in FIG. 2, it is important to limit the size of the electron beam to be smaller because the size of the electron beam must be smaller than the width of one black stripe (BM) plus one phosphor stripe so that the electron beam does not hit the other color.

Furthermore, as shown in FIG. 3, the front glass constituting the color cathode ray tube is not vertically arranged due to its geometric shape, but appears in an inclined form at the periphery of the screen.

This shape is more severe as the color cathode ray tube is enlarged and planarized. According to the experiment, the angle formed with the vertical is inclined more than 15 degrees in the case of 29 inches.

Since the inclined electron beam also adversely affects the increase in the horizontal size of the electron beam, it is also difficult and important to improve the beam tilt of the beam index color cathode ray tube.

In this case, as shown in FIG. 4, when the screen is divided into a plurality of deflection parts and an electron gun, the distance between the electron gun and the screen can be reduced, thereby reducing the overall length of the color cathode ray tube.

For example, as shown in FIG. 5, in the case of the 30-inch color cathode ray tube, the total length of the shadow mask type color cathode ray tube (dotted line) using only one electron gun or the beam index color cathode ray tube was 460 mm (B). When configured in the form as shown in Figure 4 using four 15-inch small deflection portion, the total length is 260mm (A) can reduce the length of about 40% or more.

Therefore, the volume of the TV set using the color CRT is also relatively reduced, allowing slippage.

In addition, even if the current of the electron beam is the same, the longer the distance between the electron gun and the screen is, the larger the size of the electron beam becomes in proportion, so that the total length is reduced by about 40%, and the size of the electron beam can be reduced to about 40%, enabling high resolution TV. .

Therefore, in order to realize the high resolution TV, the screen is divided as shown in FIG. 4 to reduce the distance between the electron gun and the screen, thereby solving the problem of electron beam tilt and electron beam size.

In other words, the electron gun scanning the electron beam and the deflection coil deflecting the electron beam are arranged in the divided areas of the screen to reduce the electric field of the color cathode ray tube and reduce the distance between the screen and the electron gun to solve the electron beam problem. .

However, in the case of the color cathode ray tube, the AGING occurs due to the dispersion during manufacture and the dispersion of raw materials constituting the cathode in the case of the electron gun.

In this case, in the color cathode ray tube using only one electron gun, the local luminance decrease does not appear because the current of the electron beam emitted from the electron gun cathode decreases and thus the luminance decreases.

However, in the case of the multi-segmentation cathode ray tube, the brightness of the screen varies depending on the divided region according to the time-dependent change of the electron gun scanning the divided region. It deteriorates rapidly as this time passes.

In other words, in the case of a multi-division cathode ray tube, the luminance of each divided region is initially set to be the same, and thus no problem occurs, but a change in the radiation characteristics with the electron gun dispersion occurs over time.

Accordingly, an object of the present invention is to provide a multi-beam multi-column index color cathode ray tube using a plurality of electron guns, by adjusting to maintain the same brightness on the multi-divided screen, thereby correcting image degradation due to changes in the electron gun over time. I'm trying to get it.

1 is a longitudinal sectional view of a typical beam index color cathode ray tube;

Figure 2 is an electron beam of the present invention multi-segment beam index color cathode ray tube

Figure 3 is an electron beam irradiation state diagram of the present invention multi-segment beam index color cathode ray tube

Figure 4 is a mounting side view of the present invention multi-segment beam index color cathode ray tube

Figure 5 is a mounting plan view of the present invention multi-segment beam index color cathode ray tube

Figure 6 is a control block diagram of the present invention multi-segment beam index color cathode ray tube

7 is an improvement of the electron gun characteristics of the present invention multi-segment beam index color cathode ray tube

Curve

8 is an improvement of the electron gun characteristics of the present invention multi-segment beam index color cathode ray tube

Curve

Figure 9 is a low current and high current index of the present invention multi-segment beam index color cathode ray tube

Signal waveform diagram

In order to achieve the above object, the present invention includes: a light condenser for condensing index light, which is periodically obtained from an index stripe, from an electron beam emitted from an electron gun which sets luminance for each of the divided regions; A controller configured to adjust the amplification coefficient by calculating the intensity of the index light collected by the condenser and calculating the cathode current and the voltage for each divided region at a predetermined period; And a memory unit for storing the intensity peak value of the index light adjusted to the controller, the cathode voltage, and the current.

Therefore, according to the present invention, the intensity of the beam index light irradiated from the multi-segmented beam index cathode ray tube whose initial brightness is set on the electron gun for each divided region and the luminance is adjusted on the screen for each divided region is measured, and each divided By correcting the amplification coefficient that adjusts the cathode current and voltage for each region, it is possible to implement a better image quality by preventing the occurrence of a local luminance difference due to the change of the electron gun over time.

Hereinafter, described in detail with reference to the accompanying drawings, preferred embodiments of the present invention.

Fig. 6 is a control block diagram of a multi-split beam index color cathode ray tube of the present invention, comprising: a light collecting part 60 for exciting (light absorbing) an electron beam scanned from a plurality of electron guns for each of the multi-divided regions in an index stripe; A photodetector (61) for detecting the beam index collected by the condenser (60); A bandpass filter 62 which passes only an arbitrary band frequency with respect to the beam index detected by the photodetector 61; A limiter 63 for limiting the frequency of the band passed from the band pass filter 62; A phase synchronizing loop (64) for synchronizing the phase with respect to the frequency limited in the limiter (63); A ring counter (65) for counting an index signal phase-locked from the phase lock loop (64); An index signal processing unit (600) configured from a color signal switch unit (66) for outputting a color signal according to the signal counted by the ring counter (65); In the multi-segmented beam index color cathode ray tube consisting of an amplifier 67 which amplifies a color signal output from the index signal processor 600 and applies it to an electron gun, the light collecting unit of the multi-divided area-specific beam index color cathode ray tube ( A controller 68 which adjusts the amplification coefficient by calculating the signal current and voltage for each divided region at predetermined intervals based on the intensity of the beam index signal condensed from (60); The memory 68 is configured to store the intensity peak value of the index light adjusted to the controller 68, the cathode voltage, and the current.

According to the present invention configured as described above, the electron beam scanned from the electron gun of the tube to the fluorescent surface is excited in the index stripe, and the excited beam index signal is condensed by the condenser 60, and the focused beam is photodetector 61. It is detected through.

Accordingly, the photodetector 61 passes the detected index beam through a band pass filter 62, and passes only a frequency of a predetermined band, limits the amplitude at the limiter 63, and phase-locks the phase-locked loop 64. Input to the ring counter 66.

Therefore, the image is constructed by scanning the color signal from the color signal switch 67 on the color phosphor stripe based on the index signal counted by the ring counter 66.

In realizing an image by scanning a color signal as described above, when the image for each of the multi-division regions is first adjusted, the controller 68 cuts the electron beam from the cathode of the electron gun on the screen as shown in FIG. 7. CUT OFF POINT (C) and DRIVE POINT (G) to set the entire screen to a constant current are set.

Therefore, initially, the cathode voltage is applied to the cutoff point and the drive point set by the controller 68. At this time, the current value is almost constant with respect to the cathode voltage, so that each electron gun (electron gun 1, electron gun 2 in the 4-split screen) is applied. There is almost no difference in luminance between the divided regions where the electron beams are scanned from the electron guns 3 and 4, resulting in an even luminance distribution over the entire screen.

However, as time passes, changes over time occur due to inherent dispersions of the electron guns.

That is, as shown in FIG. 7, at the cathode voltage corresponding to the initial cutoff point C and the drive point G, a different cathode current value is displayed.

Therefore, due to the variation over time of each electron gun, for example, different current values are displayed for each electron gun, and the screen brightness of the area in which they are dividedly scanned causes nonuniformity due to this cathode current distribution.

In this case, a part of the screen is bright and a part of the screen is dark, and the image quality deteriorates rapidly.

Accordingly, the controller 68 receives the index light collected by the light collecting unit 60 of the beam index color cathode ray tube through the photodetector 61, and as shown in FIG. The peak intensity or the average intensity of the index light is measured in the low current region (PL) and the high current region (PH).

At this time, the peak value low current region PL and high current region PH of the index light and corresponding cathode voltages VL and VH are stored in the memory unit 69.

The controller 68 of the beam index color cathode ray tube corrects the cathode voltage of the electron gun at predetermined intervals (1/60-1/30 second not recognized by the eye).

In other words, because of electron gun characteristics, the cathode current and the cathode voltage are almost inversely linear. Therefore, the peak value when the same voltages VL and VH are applied, the low current region (Peck value; PL1) and the high current region (peak value; PH1) are read. Will be corrected.

Slope (amplification factor) =

Since we know the initial slope at, we can see the degree of change over time by looking at the slope after a predetermined time.

That is, if the slope after the initial and predetermined time elapses is known, the cut-off voltage VC1 corresponding to the cut off point (CUT OFF POING C) after the predetermined time elapses is VC1 = PL1 / PL × VC (initial cutoff voltage). Obtain from

Therefore, the amplification factor and the cut-off voltage (VC1) can be determined, so that the television set can be automatically calibrated based on this value to keep the electron beam current by the electron gun constant.

By applying the same to the remaining electron gun in the same manner as above, an even luminance distribution can be displayed over the entire screen.

As described above, the present invention is a multi-segment beam index color cathode ray tube using a plurality of electron guns, which collects index light periodically obtained from an index stripe in an electron beam emitted from the electron gun, and peaks of current according to the intensity of the index light. By measuring the intensity of the measured index light by the controller at a predetermined period, and correcting the amplification coefficient for adjusting the cathode current and voltage for each divided region, thereby preventing the occurrence of local luminance difference due to the change of the electron gun over time. It will provide an effect that can implement a better image quality.

Claims (1)

A photodetector for detecting a beam index condensed from the condenser for exciting an electron beam scanned in the index stripe from a plurality of electron guns for each of the divided regions; In the multi-segment beam index color cathode ray tube which filters the beam index signal detected by the photodetector and sequentially scans color signals through a limiter, a phase synchronization loop, a ring counter, and a color signal switch unit, a plurality of houses for each of the multi-divided regions. A controller configured to adjust the amplification coefficient by calculating the current and voltage for each divided region at a predetermined period based on the intensity of the beam index collected from the miner; And a memory unit for storing the intensity peak value of the index light adjusted by the controller, the cathode voltage, and the current.