Radiation imagery chemistry: process – composition – or product th – Producing cathode-ray tube or element thereof
Patent
1995-02-28
1996-12-10
Rosasco, S.
Radiation imagery chemistry: process, composition, or product th
Producing cathode-ray tube or element thereof
430 24, 430 25, G03C 500
Patent
active
055829406
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a new method for forming graph scales on the panel of a CRT for oscilloscope, in method for forming graph scales on the panel by Exposition & Development System being characteristic of placing between a negative mask for the graph scale patterns and a light source a specific filter whose light transmissivity at its center is about 62% and gets larger along from its center to its peripheral portions.
In general, for example as shown in FIG. 1, the graph scale patterns including the scales for graph coordinates 1 and other necessary numerical values 2 are drawn on the surface of the panel(P) of the CRT for a oscilloscope. In the past, these graph scale patterns have been made by the method of attaching on the panel a transparent plastic board on which the necessary graph patterns are provided, but recently either by one method in which the graph patterns are directly drawn on the panel surface before complishing a glass bulb consisting of a Panel part and a Funnel part or by another method of forming the necessary graph scale patterns on the inner surface of the panel by light exposure and development means well known to the CRT manufacturers. In the above, the latter is preferred above all owing to its lower cost and the advantage in recycling the glass bulb.
One recent method frequently used by CRT manufacturers is as follows: downward, is filled with a slurry comprising suitable pigment, water, photo-sensitive agents and so on. Negative mask(M), a film on which a negative graph scale patterns 1' are provided for example as shown in FIG. 2, is arranged outside the panel part in parallel to the panel part. Then, the necessary graph scale patterns are obtained by exposing and developing the slurry precipitates deposited on the inner surface of the panel part of the bulb by the light from a light source.
The above-mentioned method has the problems as follows; monochromatic light beams but provides light beams of various wavelengths. Therefore, it is difficult to obtain correct graph scale patterns since the refractive index of the light beams passing through the collimating lens means are different from each other. since the lamp is not a point-light source but is a surface-light source. lens means themselves and the intensity of light drops due to the light transmissivity of each of the lens means. large number of lens means should be used in order to get correct collimating light beams. As a result, the intensity of the light is significantly reduced when it reaches the slurry precipitates.
In the above, if the graph scale patterns made without the lens means so as to solve the above-mentioned problems involved in using them, the obtained graph scale patterns may be different from the intended ones because of the odds of the incident angles of light arrived at each position of the mask and the panel. Also the ideal pattern lines with a uniform thickness can not be obtained due to the odds of the intensity of light arriving at each parts of the panel.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved method that can effectively solve the problems mentioned above in forming graph scale patterns on the panel of a CRT, particularly to provide a method with the outstanding feature and benefit of being able to make the ideal graph scale patterns as required using a specific filter means as described hereinafter.
To accomplish the object of the present invention, there is provided a method for forming graph scale patterns on the panel of a CRT for oscilloscope comprising the steps of exposing and developing the slurry precipitates deposited on the inner surface of the panel with the light from a light source passing through a mask film which has the negative of the graph scale patterns to be formed, a glass plate and the panel, characterized in that a specific filter is used whose light transmissivity gets larger along from its center to its peripheral portions. Preferably, the light transmissivity of the filter
REFERENCES:
patent: 4983499 (1991-01-01), Sazuki et al.
Orion Electric Co. Ltd.
Rosasco S.
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