JPH1145066A - Field sequential type cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase picture display brightness without requiring a high speed scanning and to achieve a precision picture by letting each of plural electron beams simultaneously scan scanning areas equally divided on a fluorescent surface. SOLUTION: A white cathode ray tube 9 emits light by letting electron beams 3a-3c emitted from an electron gun 8 collide against a fluorescent screen 4 kept at a high potential. The electron beams 3a-3c are emitted from the electron gun 8 so that each interval on the fluorescent screen 4 becomes 1/3 of the vertical main scanning range. In this state, the electron beams 3a-3c are simultaneously deflected by a deflection yoke 2 and scan each 1/3 of the main scanning range, respectively, for reproducing a field of picture. Video signals, of which a total number of scanning lines are divided into three by one field unit and stored, are read in the order of red, green, and blue by enable signals 11 and supplied to the electron gun 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field sequential type cathode ray tube.

[0002]

2. Description of the Related Art A cathode ray tube of a liquid crystal shutter system will be described as an example of a field sequential cathode ray tube. FIG. 7 is a sectional view of a conventional liquid crystal shutter type cathode ray tube. In the figure, 1 is an electron gun for emitting one electron beam 3, 2 is a deflection yoke for deflecting the electron beam 3 emitted from the electron gun 1, 4 is a fluorescent screen which emits light when the electron beam collides, Reference numeral 5 denotes a glass bulb, which constitutes a white cathode ray tube 6 which emits white light with these components. Reference numeral 7 denotes a liquid crystal shutter provided in front of the phosphor screen of the white cathode ray tube 6, and is generally configured by combining a birefringent liquid crystal filter and a polarizing filter.

Next, the operation will be described. The white cathode ray tube 6
When the electron beam 3 emitted from the electron gun 1 collides with the phosphor screen 4 maintained at a high potential, the electron beam 3 emits white light. The electron beam 3 is deflected by the deflection yoke 2 and scans the phosphor screen 4 in the horizontal and vertical directions to form a raster (scanning area). In this raster, points (light spots) that emit light when the electron beam 3 hits the phosphor screen 4 are arranged in order, and the light emission of each light point is adjusted by adjusting the amount of hit of the electron beam 3. The intensity is changed and a light emission image is displayed on the fluorescent screen 4. This luminescent image passes through the glass bulb 5 which is the envelope of the white cathode ray tube 6, and is recognized as a white image.

[0004] The liquid crystal shutter 7 is installed immediately before the display surface of the white cathode ray tube 6, and the fluorescent screen 4 of the white cathode ray tube 6 is provided.
From the white emission light of the emission image displayed in, red, green,
The blue primary color light is selectively transmitted. Therefore, by observing the display image of the white cathode ray tube 6 through the liquid crystal shutter, red, green and blue images can be reproduced.

In such a display system, three-color images cannot be displayed at the same time as in a general cathode ray tube of a shadow mask system. Accordingly, in the field sequential type cathode ray tube, one-third of a normal one field period (time required to form one unit image on a phosphor screen by electron beam scanning) used in a shadow mask type cathode ray tube or the like. Are assigned to each of the red, green, and blue images.
A color image is reproduced by sequentially displaying red, green, and blue images during the field period.

[0006]

Since the conventional liquid crystal shutter type cathode ray tube, which is a conventional field sequential type cathode ray tube, is constructed as described above, in a field sequential type color image display, three colors are set within one field period. Must be sequentially output, and the image signal of each color is output within 1/3 of one field period. Therefore, high-speed scanning is required with a scanning period of 1/3 that of the normal method, and at the same time, the irradiation time of the electron beam on the phosphor screen is also reduced by 1/3. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a field-sequential cathode-ray tube which does not require high-speed scanning, improves image display luminance, and can obtain a high-precision image. The purpose is to:

[0008]

A field sequential type cathode ray tube according to the present invention has an electron gun for emitting a plurality of electron beams at the same time. A plurality of equally divided scanning regions are simultaneously scanned.

Further, in the above configuration, a correction deflecting means for deflecting an arbitrary electron beam out of the plurality of emitted electron beams independently of each other is provided.

Further, the number of emitted electron beams is three.

[0011] Further, there is provided a correction deflecting means capable of independently deflecting two of the three electron beams.

Further, the correction deflecting means is constituted by an electromagnetic device.

Further, the correction deflection means is constituted by an electrostatic device.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 8 denotes three electron beams 3
a, 3b, and 3c are simultaneously emitted in the same plane (in the same vertical plane in the present embodiment), and include three unit electron guns for each beam. Reference numeral 2 denotes a deflection yoke for simultaneously deflecting the three electron beams 3a, 3b, and 3c emitted from the electron gun 8, reference numeral 4 denotes a fluorescent screen which emits light when the electron beams impinge, and reference numeral 5 denotes a glass bulb. The white cathode ray tube 9 is constituted. Reference numeral 7 denotes a liquid crystal shutter provided in front of the fluorescent screen 4 of the white cathode ray tube 9.

Reference numeral 12 denotes a video signal circuit for supplying video signals of three colors of red, green, and blue. Reference numerals 13a, 13b, and 13c denote red, green, and blue video signals from the video signal circuit 12 in units of one field. A memory for red, green, and blue signals that is divided and stored sequentially for each one-third of the number of lines,
Reference numeral 5 denotes a liquid crystal filter control circuit for controlling the orientation of the liquid crystal filter of the liquid crystal shutter 7. In this embodiment, three electron beams 3a, 3a,
b and 3c are arranged in the vertical direction of the fluorescent screen 4, that is, on the vertical line.

Next, the operation will be described. The white cathode ray tube 9 is
Light is emitted when the electron beams 3a, 3b, 3c emitted from the electron gun 8 strike the fluorescent screen 4 maintained at a high potential. As shown in FIG. 1, the three electron beams 3a, 3b, and 3c are emitted from the electron gun 8 so that each interval on the fluorescent screen 4 is 1/3 in the vertical direction of the scanning range. You. In this state, the three electron beams 3a, 3b and 3c are simultaneously deflected by the deflection yoke 2, and as shown in FIG. 2, each of the three electron beams 3a, 3b and 3c scans one third of the scanning range. Then, an image for one field is reproduced.

The video signals stored in the memories 13a, 13b and 13c are read out in order of red, green and blue by an enable (EN) signal 14, and supplied to the electron gun 8. Looking at each color, the video signal of the first ３ line is applied to the unit electron gun that emits the electron beam 3b,
The video signal of the ３ line is simultaneously supplied to the unit electron gun that emits the electron beam 3a, and the video signal of the last ラ イ ン line is simultaneously supplied to the unit electron gun that emits the electron beam 3c. For example, if the total number of lines is 1200 lines,
As shown in FIG. 2, an image of 1 to 400 lines is drawn on the electron beam 3b, an image of 401 to 800 lines is drawn on the electron beam 3a, and an image of 801 to 1200 lines is drawn on the electron beam 3c. This operation is repeated in the order of red, green, and blue to reproduce an image for one field.

In short, as shown in FIG. 2 (i) when the upper end is deflected, the first electron beam 3b, the 401st line of the electron beam 3a, and the 801st line of the electron beam 3c are drawn. . Each electron beam 3a, 3b, 3c is simultaneously scanned from the left end to the right end by the deflection yoke 2, and then the operation returning to the left end is repeated so that each electron beam 3a, 3b, 3c draws an image of the next line. Scanning is performed sequentially, and each of them is scanned one-third of the entire scanning range as in the case of iii) lower end deflection in FIG.
Reproduce the image for the field. When a red image is thus reproduced, for example, the enable (EN) signal 1
4 supplies the next green video signal stored in the memory 13 b to the electron gun 8. When the green image is reproduced,
Similarly, the next blue video signal stored in the memory 13c is supplied to the electron gun 8.

For the control of the liquid crystal shutter 7, for example, a voltage is applied to the liquid crystal filter of the liquid crystal shutter 7 so as to transmit the three primary colors in the order of red, green, and blue to change the orientation of the liquid crystal. The timing of applying a voltage to the liquid crystal filter to change the orientation of the liquid crystal is every ３ field.

Embodiment 2 In the first embodiment, the three electron beams 3 a, 3 b, and 3 c are emitted from the electron gun 8 so that the intervals on the fluorescent screen 4 are １ ／ of the vertical direction of the scanning range. However, in order to increase the accuracy in consideration of the accuracy at the time of manufacturing the cathode ray tube and the effect of an external magnetic field during operation, two of the three electron beams are independently deflected. Correction deflecting means is provided.

FIG. 3 shows a field sequential type cathode ray tube provided with correction deflection means. In the figure, 10 is 3
This is a correction deflection yoke that deflects two electron beams 3b, 3c out of the three electron beams 3a, 3b, 3c. FIG. 4 shows the structure of the correction deflection yoke. 10a, 10
b is a correction deflection yoke for generating a correction deflection magnetic field. A current can be supplied to the coils of the respective correction deflection yokes 10a and 10b independently from the terminals A and B and the terminals C and D to generate a necessary correction deflection magnetic field. With the correction deflection magnetic field, the two electron beams 3b and 3c are corrected and deflected independently of the electron beam 3a out of the three electron beams, so that the three electron beams on the phosphor screen are Correct the interval accurately.

Embodiment 3 FIG. In the second embodiment, three electron beams 3a, 3b,
The correction means for correcting and deflecting the two electron beams 3b and 3c of the electron gun 3c has been shown. However, as shown in FIGS. The same effect can be obtained by using a correction deflecting unit that electrically performs correction deflecting. Note that the direction and magnitude of the current applied to each electrode can be independently performed as in the second embodiment.

In the above-described first to third embodiments, the electron beams 3a, 3a
Although b and 3c are arranged vertically, the positions of the electron beams 3a, 3b and 3c emitted from the electron gun 8 are not particularly limited as long as they come to predetermined positions on the fluorescent screen 4.

Further, FIGS. 4, 5 and 6 of the second and third embodiments are merely examples, and shapes and the like may be different as long as they have the same function. .
In the above description, the three electron beams 3a, 3b, 3
Although the case of c has been described, the invention can be similarly applied as long as it emits a plurality of electron beams. In that case,
The equal division in the vertical direction on the phosphor screen 4 is equal to the number of electron beams. Furthermore, the deflection can be corrected independently by the number of electron beams by the number of electron beams.

[0025]

As described above, according to the present invention, a plurality (N) of electron beams are emitted at the same time, and each electron beam scans and displays 1 / N of the display image. High-speed scanning is not required, color display can be performed in a normal field period, and a field-sequential cathode ray tube without a decrease in image luminance can be obtained.

Further, by providing the correction deflection means,
An error that occurs during manufacturing and use is corrected, and higher-precision display is enabled.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a field sequential cathode ray tube according to Embodiment 1 of the present invention.

FIG. 2 is a diagram for explaining the operation of the first embodiment.

FIG. 3 is a longitudinal sectional view showing a field sequential cathode ray tube according to a second embodiment of the present invention.

FIG. 4 is a front view showing a correction deflection unit used in the second embodiment.

FIG. 5 is a side view showing a correction deflection unit used in Embodiment 3 of the present invention.

FIG. 6 is an enlarged view showing a cross section taken along line AA ′ of FIG. 5;

FIG. 7 is a longitudinal sectional view showing a conventional field sequential type cathode ray tube.

[Explanation of symbols]

2 deflection yoke, 3a, 3b, 3c electron beam, 4
Phosphor screen, 5 glass bulb, 7 liquid crystal shutter, 8 electron gun, 9 white cathode ray tube, 10 correction deflection means, 10
a, 10b Correction deflection yoke, 11 Correction deflection electrode.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 9/18 H04N 9/18

Claims (6)

[Claims] 1. A field sequential type cathode ray tube having an electron gun for simultaneously emitting a plurality of electron beams, wherein the plurality of electron beams simultaneously scan a plurality of equally divided scanning regions on a phosphor screen. A field-sequential cathode ray tube characterized by the following. 2. The field sequential cathode ray tube according to claim 1, further comprising a correction deflecting means capable of deflecting any one of the plurality of emitted electron beams independently of each other. 3. The field-sequential cathode ray tube according to claim 1, wherein the number of emitted electron beams is three. 4. A field sequential cathode ray tube according to claim 3, further comprising correction deflection means capable of independently deflecting two of the three electron beams. 5. A field sequential type cathode ray tube according to claim 2, wherein the correction deflection means is constituted by an electromagnetic device. 6. A field sequential type cathode ray tube according to claim 2, wherein the correction deflection means is constituted by an electrostatic device.