JPS63164143A - Black matrix type color cathode-ray tube - Google Patents

Abstract

PURPOSE:To make it possible to prevent the coloring of red color from being stronger than the coloring of blue and green, which causes a deterioration of a white color unevenness, and to improve the evenness of the white color, by making the dot diameters or the stripe widths of color phosphor patterns which are formed at the positions other than those covered by the black matrix graphite, in the condition as red<blue<green patterns. CONSTITUTION:In order to form a black matrix, a photoresist film is spread before a graphite film is spread, and after a panel is heated to a specific temperature, the exposure is operated. In this case, when a photoresist whose exposure sensitivity is lower at the high temperature than at the low temperature is used, the exposure is operated in the order, red, blue, and green phosphor patterns, and when the photoresist whose exposure sensitivity is low at a low temperature than at a high temperature is used, it is operated in the order, green, blue, and red phosphor patterns, so as to make the dot diameters or the stripe widths of them in the condition as red<blue<green patterns constantly. In such a way, a black matrix cathode-ray tube in which the evenness of white color of the display screen of the color cathode-ray tube is improved visually can be obtained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention improves a method for forming a black matrix that improves the contrast of a display screen of a color cathode ray tube, and improves the white uniformity of the screen display at least in terms of luminous efficiency. This invention relates to an improved black matrix type color cathode ray tube.

[Conventional technology]

Dot-shaped or striped patterns of phosphors that emit light in the three primary colors of red, green, and blue in color cathode ray tubes, and black where the panel surface around the phosphor patterns is completely coated with graphite to improve the contrast of the display screen. As is well known, the process of forming the matrix uses photolithography technology, and 3J (separate electron guns are used for each color).

The 3H color phosphor pattern was individually and repeatedly exposed to a photoresist film, a photosensitive phosphor film, etc. through a shadow mask.

A patent application has already been filed regarding the exposure order of the three primary color phosphor patterns during the above-mentioned formation process, but the purpose of the conventional invention was to reduce costs by repeatedly using the photosensitive phosphor slurry, extending its life, etc. .

The main purpose was to prevent color mixing.

To apply phosphor, the following steps are usually performed for each color: coating a photosensitive phosphor film, exposing, developing, and forming a solidified phosphor film in the desired pattern. To create a black matrix of graphite that completely covers the peripheral panel surface, a photoresist film is first applied to the panel surface prior to the application of the phosphor described above, and a pattern for each color phosphor is sequentially exposed to light on this photoresist film for a total of three times.
After repeated development, a graphite film is coated on top of this, and the graphite film formed on the photoresist that remains assimilated into the phosphor pattern area is etched to rev-I-off each underlying photoresist layer. are doing.

Conventionally, no special considerations or patent applications have been made regarding the order of exposure of each color phosphor pattern to the photoresist in step 1 of "forming a black matrix."

[Problem that the invention seeks to solve]

The present invention improves the black matrix forming method,
An object of the present invention is to provide a black matrix type cathode ray tube in which the white uniformity of the display screen of the color cathode ray tube is improved at least in terms of visibility.

[Means for solving problems]

To achieve the above object, in the present invention, in order to form a black matrix, a film is applied to the photoresist 1 prior to coating the graphite film, and the panel is heated to a predetermined temperature before exposure work is performed. When using a photoresist that has lower exposure sensitivity at high temperatures than at low temperatures, the patterns for red, blue, and green phosphors are used in this order; The dot diameter or stripe width of the phosphor pattern was always red, blue, and green.

[Effect]

There is no problem with the white uniformity of a color cathode ray tube display screen if the three color picture elements are the same size, but even if there is an imbalance in the light emission of the three temporary colors, it is not of much concern to the tcat PA operator. It is divided into cases and cases not. The main cause of this deterioration of white uniformity is, of course, the imbalance of the three colors, but due to the influence of the visibility range, magenta unevenness and yellow unevenness occur when red light is strong, and yellow unevenness occurs when green light is strong. Makes cyan unevenness stand out and makes white unevenness worse. That is,
If the red light emission is too strong, white unevenness will deteriorate in terms of visibility, but if the opposite is the case, it will not be noticeable.

In the exposure work for the photoresist for forming a black matrix, one minute or more passes between the time when the first exposure is performed and the time when the last exposure is performed. Prior to exposure, the temperature of the panel is raised to a predetermined temperature, but as mentioned above, time passes while each color phosphor pattern is exposed, and the panel temperature decreases, so it is difficult to expose the photoresist. The degree of chemical change (sensitivity) caused by exposure differs depending on the exposure order.

For example, with FAA (polyacrylamide) photoresists, the higher the panel temperature, the lower the sensitivity, and the diameter or width of the pattern exposed first becomes smaller and increases in the order of exposure. In addition, PVA (polyvinyl alcohol) type,
In the ADC (ammonium dichromate) system, the lower the panel temperature, the worse the sensitivity, and the diameter or width of the pattern exposed first becomes larger and becomes smaller in the order of exposure.

As described above, the photoresist for forming the black matrix is greatly affected by fluctuations in panel temperature and processing temperature, and as a result, the size of the picture elements of the three-color phosphor is also affected. However, if the photoresist exposure order is as described above, the dot diameter and stripe width of the phosphor pattern can be easily maintained in the order of red, blue, and green, and if work management is careful, the size of each color pattern can be made uniform. It is possible to improve the white uniformity. Paying attention to work management refers to, for example, dealing with constant temperature fluctuations by appropriately adjusting the exposure amount for each color. Since the exposure apparatus performs sequential operation, the exposure order and exposure amount can be set as desired.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

A shadow mask 2 is attached to the panel 1 that has been coated with photoresist, and after being left on the conveyor for 15 to 20 minutes, it is installed in an exposure device. The temperature during photoresist film formation is, for example, 60°C (to evaporate moisture in the photoresist), but 1
For example, the room! At 25°C, the temperature changes from 42°C during the first exposure to 35°C during the final exposure. When a PAA-based photoresist is used, exposure is first performed at a position for a red pattern, and then the position of the exposure light source 3 is sequentially moved to perform exposure at a position for a blue pattern and a position for a green pattern. - Color exposure is approx. 25
One cycle is completed in 90 to 120 seconds. If the photoresist is PVA type or ADC type,
The above exposure order may be reversed.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent red coloring from becoming stronger than blue and green colors, which is a cause of deterioration of white unevenness, and white uniformity is improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention. l...Panel, 2...Shadow mask, 3.3...
・Exposure light source

Claims (1)

[Claims] 1. In a black matrix type color cathode ray tube, the panel surface around the dot or stripe pattern of red, blue, and green phosphors formed on the inner surface of the panel is completely covered with graphite to improve the contrast of the display screen. A black matrix type color cathode ray tube characterized in that the dot diameter or stripe width of a pattern of each color phosphor formed in a portion of the black matrix not covered with graphite is such that a red < blue < green pattern.