JPS61118088A - Beam index system color picture reproducing device - Google Patents

Abstract

PURPOSE:To prevent that a color is stuck to a part which becomes white originally when a thin white longitudinal line is reproduced by forming a three primary colors color phosphor stripe and an index phosphor stripe to the angle which will not be orthogonal in the horizontal scanning direction. CONSTITUTION:To an inner surface of a face plate 1 of a beam index tube, a three primary colors color phosphor of red 2, green 3 and blue 4 is repeatedly coated at the angle theta which is not orthogonal in the stripe shape in the horizontal scanning direction. An index phosphor 5, which emits the light with a short afterglow time except a visible area between red and blue phosphor stripes, is repeatedly coated in the stripe shape in parallel to a three primary colors color phosphor stripe. By constituting like this, in a beam index system color picture reproducing device excellent in a focus characteristic, the sticking of the color of the white longitudinal line, which occurs when a thin white longitudinal line or a white character is reproduced, can be prevented.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a beam index type color image reproducing device, and particularly relates to a phenomenon in which color appears when thin white vertical lines or white characters are reproduced. The present invention relates to a color image reproducing device that makes it possible to prevent such problems.

[Background of the invention]

For example, Japanese Patent Publication No. Sho 42-5426 describes the phosphor screen structure of a beam index tube used in a beam index type color image reproducing device.

The basic structure of the phosphor screen of a conventionally known beam index tube will be explained with reference to FIG. The inner surface of face plate 1 is red 2. Green 3. The three primary color phosphors of blue 4 are repeatedly applied in a vertically continuous stripe pattern, and the index phosphor 5 is also repeatedly applied in a specific arrangement relationship with the three primary color phosphors.

When reproducing thin white vertical lines or white characters using the above beam index tube, the focus characteristics of the beam index tube are good and the beam spot diameter is small.
Depending on the relative position of the white vertical line and the colored phosphor stripes on the phosphor screen, a specific color appears (in the case of FIG. 2, the electron beam 6 causes some red and green parts to appear).

The blue, red, green, and some blue phosphor stripes emit light, making the white vertical line appear greenish).

In the shadow mask method, six electron guns are used to emit red, green, and blue phosphors at the same time, so the white vertical lines are reproduced as white and do not appear colored.

On the other hand, the beam index method uses red and green.

Since it is a blue dot sequential method and the input video signal is not synchronized with the scanning time of the phosphor stripe of the electron beam, depending on the time width of the video signal, even if it is a white video signal,
The balance of the amount of light emitted by the three-color phosphors of red, green, and blue may not be maintained.

Also, if the focusing characteristics are not good with an index tube,
A color image with high color saturation? Since it cannot be reproduced, it is necessary to improve the focus characteristics and obtain a small beam spot diameter.
are doing. For this reason, when a thin white vertical line is reproduced, a problem arises in that the vertical line portion, which should originally be white, appears colored.

[Purpose of the invention]

An object of the present invention is to provide a beam index type color image reproducing device that can prevent thin (or white vertical lines from being colored) in the originally white portion and obtain a high-quality reproduced image. There is a particular thing.

[Summary of the invention]

In the beam index color image reproducing apparatus of the present invention, a beam index tube having a phosphor screen structure in which three primary color phosphor stripes and index phosphor stripes are scattered at angles not orthogonal to the horizontal scanning direction is used. Achieved the purpose.

[Embodiments of the invention]

Hereinafter, six embodiments of the present invention will be described with reference to FIGS. 1 and 5. FIG. 1 is an explanatory diagram showing a phosphor screen structure of a beam index tube as a main part of an embodiment of the present invention, and FIG. 5 is an explanatory diagram showing an outline of the configuration of a beam index type color image reproducing device. .

In Fig. 1, the inner surface of the face plate 1 of the beam index tube has a red mark 2. Three primary color phosphors of green (a6, blue a3, and 4) are repeatedly applied in stripes at an angle θ (θ+90') that is not perpendicular to the horizontal scanning direction (X direction) to form a phosphor screen. Between the red and blue phosphor stripes, an index phosphor (1) 5 that emits light with a short afterglow time in a region other than the visible range is repeated in a stripe pattern Km parallel to the three primary color phosphor stripes.

An aluminum metal back layer (not shown) is deposited on the inner surface of the phosphor screen, that is, on the lower side of the phosphor screen, as in a normal cathode ray tube.

In FIG. 5, the electron beam 6 emitted from the electron gun 7 is scanned by the deflection yoke 8 in the horizontal direction (X direction) and the vertical direction (X direction) to form a raster on the phosphor screen.

Visible light from the five primary color phosphors and light from the index phosphor are emitted from the phosphor screen excited by the electron beam 6 to the front of the face plate 1. A photoelectric converter 9 is arranged in front of the face plate 1 to photoelectrically convert the optical index signal to obtain an index signal.

The index signal and the video signal supplied to the video signal input terminal 10 are supplied to an index signal processing circuit 11 to form a drive signal for the beam index tube. A driving signal is applied to the negative pole (not shown) of the electron gun 7 or to the first grid electrode (not shown) to reproduce a color image.

In the present invention, three primary color phosphor stripes are arranged in the horizontal scanning direction (
The angle θ (θN is set to 90) which is not perpendicular to the X direction). Therefore, when a thin white vertical line is reproduced, colored phosphor stripes emit light at both ends of the vertical line depending on the vertical position (X direction) of the white vertical line. For example, in the scanning line at the top of the vertical line, part of red, green, blue, red, 8, and part of green color phosphors emit light. ), part of the blue color phosphor stripe and part of the red, green, blue, and red color phosphor stripes emit light.For this reason, the white balance of the white vertical line varies by a minute amount depending on the position of the vertical line in one direction. When you look at the vertical lines with the naked eye, they are averaged and appear as normal white vertical lines.

Note that the angle of the six primary color phosphor stripes is not limited to θ>90 degrees as shown in FIG.

Furthermore, in this example, an example was explained in which one type of index phosphor is used to emit an optical index signal to the front surface of the face plate, but the index phosphor is not limited to type 1ai, and the original index signal can be emitted from the index phosphor. It goes without saying that this method can be similarly applied to the case where electrons are emitted to the lower side of the beam index tube.

〔Effect of the invention〕

According to the present invention, in a beam index type color image reproducing device with excellent focus characteristics, it is possible to prevent discoloration of white vertical lines that occurs when reproducing thin white vertical lines or white characters, so that reproduction of good quality can be achieved. This has the effect of providing an image source.

Note that the present invention is not effective when white diagonal lines parallel to the colored phosphor stripes on the phosphor screen are reproduced, but since normal images have more line segments in the vertical and horizontal directions than diagonal lines, this invention is not effective. The effects of invention are significant.

In addition, by arranging the index phosphor stripes diagonally, the index signal frequency is low.
For example, the frequency bandwidth for amplifying a weak index signal immediately after photoelectric conversion can be narrowed, and the S/N ratio can be improved.

In addition, since the time it takes for the electron beam to scan over one index phosphor stripe is longer, taking into consideration the afterglow time of the phosphor, an optical index signal with a larger amplitude can be obtained with the diagonal arrangement. This also has the effect of improving S/N.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the phosphor screen structure of the beam index tube of the present invention, Fig. 2 is an explanatory diagram showing the phosphor screen structure of a conventional beam index tube, and Fig. 3 is the configuration of a beam index method color image reproducing device. It is an explanatory diagram showing an outline. DESCRIPTION OF SYMBOLS 1... Face plate, 2... Red phosphor stripe, 3... Green phosphor stripe, 4... Blue phosphor stripe, 5... Index phosphor stripe, 6... Electron beam, 7... Electron gun, 8... Deflection yoke, 9... Photoelectric converter, 10... Video signal input terminal, 11... Signal processing circuit. Part 1 (2)

Claims (1)

[Claims] 1) In a beam index type color image reproducing device, three primary color phosphor stripes of red, green, and blue and one or more types of index phosphor stripes are arranged on the phosphor screen of the beam index tube in the horizontal scanning direction of the electron beam. A beam index type color image reproducing device characterized in that the color image is repeatedly applied at non-orthogonal angles.