JPS5845773B2 - Light control filter and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light control filter used in exposing the fluorescent surface of a color picture tube and a method for manufacturing the same.

FIG. 1 schematically shows the process of exposing the fluorescent surface of a conventional color picture tube. In FIG. A shadow mask 3 is disposed at a fixed position inside the panel 1, facing the inner surface of the panel 1.

Such a panel mask assembly 4 is mounted on an exposure table 5.
The photochromic filter 1 is placed in a fixed position above to correct the light intensity distribution on the inner surface of the panel 1 due to the light source 6, and the trajectory of the electron beam of the completed color picture tube and the light from the light source 6 during exposure. Exposure is performed through the holes in the shadow mask 3 by light from the light source 6 that has passed through a correction lens 8 for aligning with the marks.

The light control filter 7 will be explained in more detail.

Curve A in FIG. 2 represents the light intensity distribution on the inner surface of the panel 1 when the light control filter 1 is not used as a ratio to the light intensity value at the center of the panel.

On the other hand, the ideal light intensity distribution that is actually required during exposure on the inner surface of the panel 1 is determined by the photosensitive reaction of the photosensitive photoresist film or the photosensitive phosphor slurry film 2 formed on the inner surface of the panel 1 under specific conditions. It is determined by the distribution of the exposure amount necessary to achieve this, and like curve A, this can be expressed as a ratio to the light intensity at the center of the panel as shown in curve B.

The curves A and B do not match in most cases.

Therefore, in order to obtain an ideal light intensity distribution as shown by curve B on the inner surface of panel 1, a light control filter I having a predetermined light transmission weight distribution as shown in FIG. - Inserted into position between mask assembly 4.

The light control filter 7 having this predetermined light transmission weight distribution is
As shown in FIG. 4, it is made by forming a semi-transparent vapor-deposited thin film of chromium, rhodium, nickel-chromium alloy, etc. on a transparent substrate using a vacuum evaporation method so as to have a specific film thickness distribution.

FIG. 5 shows another type of light control filter 7, in which a semi-transparent vapor-deposited metal film is formed on a transparent substrate in a certain shape and with a certain transmittance, and upon exposure, as shown in FIG. By rotating the filter 7 with the motor 10 via the pulley 9, a transmittance distribution substantially as shown in FIG. 3 is obtained.

The light transmittance of the light control filter 7 is determined by the luminous intensity of the light source 6, light distribution, appropriate exposure time, etc.
The light transmittance at the center of the light control filter 7 that is usually used is in the range of about 10% to about 70%.

A major drawback in using the light control filter 7 made of a semi-transparent vapor deposited metal film as described above is that the light transmittance changes over time.

That is, X in FIG. 1 shows the relationship between the usage time of the light control filter 7 made of a conventional semi-transparent vapor-deposited thin film and the light transmittance of the vapor-deposited film. The initial light transmittance T varies depending on conditions such as the setting position of the filter 7 on the exposure device.

and the light transmittance Tt after 1000 hours.

In extreme cases, the ratio of T1 may be 2 to 3. Ru.

The reason for such a change in light transmittance is considered to be that the semi-transparent metal vapor deposited thin film undergoes physical and chemical changes due to strong ultraviolet rays and heat rays from the light source 6.

This change in light transmittance not only causes a change in exposure time from the appropriate exposure time.

In other words, this change in light transmittance does not appear at a uniform rate over the entire f of the light control filter 7, but the rate of change usually differs between the central part and the peripheral part of the light control filter 7. This makes it impossible to obtain the required light intensity distribution on the inner surface of the panel.

Such a change in light transmittance over time G''4 is more or less unavoidable in the conventional light control filter 7 made of a semi-transparent vapor deposited thin film.

The present invention was made in order to eliminate the above-mentioned drawbacks, and provides a stable light control filter with little change in light transmittance over time, and a method for manufacturing the same.

Hereinafter, FIGS. 8a and 8b, which are one example of this, will be explained.

The light control filter 7 forms a mesh-like pattern with a light-shielding portion M made of a graphite or carbon layer and a light-transmitting portion having no such layer.

Further, the area of the light-transmitting portion is configured to gradually increase from the center to the periphery of the light control filter 7.

Specifically, it is constructed by changing the pitch P or linear width W in the mesh-like pattern from the center to the periphery.

Further, the light shielding portion M is formed so as to have almost no light transmittance.

When such a light control filter 7 was used to expose a photosensitive photoresist or a phosphor slurry and its change over time was investigated, the initial light transmittance T was as shown by curve Y in FIG.

and 2 The ratio of light transmittance T2 after 1000 hours is almost O was close to 1, and no deterioration of characteristics occurred.

This is because the graphite or carbon layer forming the light shielding part M of the light control filter 7 is very stable, and the light transmittance hardly changes even when exposed to strong ultraviolet rays and heat rays from the light source 6. This is because the light transmittance of the light control filter 7 is determined by the area ratio of the light blocking portion M to the light transmitting portion.

Note that in terms of the quality of the photosensitive photoresist film or the photosensitive slurry film, the finer the mesh pattern is, the better, and although it varies depending on the shape of the light source 6 or the position of the light control filter 7, the fineness of at least 20 meshes is preferable. It was necessary.

Furthermore, if a light control filter 7 with less than 100 meshes is used, there is a risk that the mesh structure will be directly projected onto the photoresist film or phosphor slurry film surface, resulting in non-uniform exposure. The light control filter 7 may be configured to be rotated as shown in the figure.

Figures 9a and 9b show other embodiments of the invention.

In this example, the pitch P in the mesh-like pattern is
The mesh pattern is formed in a predetermined shape at a predetermined position, and the linear width W is made almost the same over the entire surface of the dimmer filter 7.As with the conventional device, the dimmer filter 7 is rotated to create a panel. The structure is such that the integrated light amount at each point on the inner surface substantially has a required distribution.

FIG. 10 shows a manufacturing process of a light control filter according to an example of the manufacturing method of the present invention.

In this example, a photosensitive film 12 containing graphite or carbon is formed on a transparent substrate 11, and a mesh-like pattern 13 such as a metal mesh is placed opposite to this photosensitive film 12.
The photosensitive film 12 is exposed to light from a light source 14 through the wafer.

Thereafter, the photosensitive film 1 is developed by, for example, spray development.
By removing the exposed or unexposed areas 2, a predetermined pattern 15 made of graphite or carbon layer is formed on the transparent substrate 11.

When a photodegradable substance is used as a photosensitive substance,
As shown in FIG. 10a, a mesh-like pattern 15 having a lattice-like light-shielding portion M made of a graphite or carbon layer and a light-transmitting portion having no such layer is obtained, and a photocurable type is used as the photosensitive material. If a substance is used, the first
As shown in FIG.
is obtained.

FIG. 11 shows the manufacturing process of a light control filter according to the other side of the manufacturing method of the present invention.

In this example, a photosensitive resist film 16 is formed on a transparent substrate 11, and the resist film 16 is exposed to light from a light source 14 through a mesh-like pattern 13, such as a metal mesh, placed opposite to this resist film 16. Let's do it.

Thereafter, by removing the unexposed portions of the resist film 16 by, for example, spray development, a fixed pattern 17 made of a hardened resist film is formed on the transparent substrate 11.

Next, a dispersed flow of graphite or carbon is uniformly applied onto the transparent substrate 11 having the pattern 1γ made of this cured resist film and dried to form the graphite or carbon layer 18.

Furthermore, if the hardened resist film is decomposed and removed using, for example, a solution containing an oxidizing agent, and at the same time the graphite or carbon layer formed on the pattern 17 made of this resist film is also removed, it will be the same as shown in FIG. 10a. A light control filter in which a mesh-like pattern is formed is obtained.

As explained above, this invention has a mesh-like pattern formed on a light-transmitting substrate by a light-shielding part made of a graphite or carbon layer and a light-transmitting part not provided with these layers. For example, it is possible to provide a light control filter with almost no change in light transmittance over time,
The fluorescent surface of the color picture tube can be exposed stably.

Further, according to the manufacturing method of the present invention, it is possible to obtain the above-described light control filter of the present invention.

[Brief explanation of the drawing]

Figure 1 is a schematic vertical cross-sectional view showing the configuration of an example of an exposure device that forms the fluorescent surface of a color picture tube, Figure 2 is a diagram showing the light intensity distribution on the inner surface of the panel, and Figure 3 is a diagram showing the light intensity distribution on the inner surface of the panel. Figures 4 and 5 are plan views showing different examples of conventional light control filters, and Figure 6 is a diagram showing the light transmittance distribution. Figure 6 is a diagram showing the exposure device that forms the fluorescent surface of a color picture tube. A schematic vertical cross-sectional view showing the coupling on the other side, FIG. 7 is a diagram showing the change in light transmittance of the light control filter over time, and FIGS. 8a and b are plane views showing one embodiment of the light control filter according to the present invention. Figures and partially enlarged views, No. 9
Figures a and b are a plan view and a partially enlarged view showing an embodiment of the same location, Figure 10 is a process explanatory diagram showing an example of the method for manufacturing a dimming filter of the present invention, and Figures 10a and b are Figure 10. FIG. 11 is a partially enlarged view showing different examples of dimming filters obtained by the manufacturing method of FIG. DESCRIPTION OF SYMBOLS 1... Panel, 2... Photosensitive photoresist film or phosphor slurry film, 3... Shadow mask, 4...
... Panel mask assembly, 5... Exposure stage,
6... Light source, 7... Light control filter, 8... Correction lens, 9... Pulley, 10... Motor, 11
...Transparent substrate, 12...Photosensitive film containing graphite or carbon, 13...Mesh-like pattern, 14...
Light source, 15... Pattern made of a graphite or carbon layer, 16... Photosensitive resist film, 17... Pattern made of a hardened resist film, 18... Graphite or carbon layer, L... Transparent portion , M... Light-shielding part. Note that the same parts in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A dimmer filter used for exposing the fluorescent surface of a color picture tube, which has a light-shielding portion made of a layer of graphite or carbon on a light-transmitting substrate, and a light-transmitting filter without such a layer. A light control filter characterized by having a mesh-like pattern formed by parts. 2. A method for manufacturing a photochromic filter used for exposing the fluorescent surface of a color picture tube, including a step of forming a photosensitive film containing graphite or carbon on a transparent substrate, and a mesh-like pattern placed opposite to this photosensitive film. a step of exposing a photosensitive film to light from a light source through a light source, and a step of developing the exposed photosensitive film, and providing a light-shielding portion made of graphite or a carbon layer on the transparent substrate and these layers. A method for producing a light control filter, characterized in that a mesh-like pattern is formed by a light-transmitting part and a light-transmitting part. 3. A method for manufacturing a photochromic filter used for exposing the fluorescent surface of a color picture tube, which includes the steps of forming a photosensitive resist film on a transparent substrate, and introducing a light source through a mesh-like pattern placed opposite to the photosensitive resist film. a step of exposing the resist film to light from a source, a step of developing the exposed photosensitive resist film, a step of applying a graphite or carbon dispersion to form a graphite layer or a carbon layer, and a step of forming a graphite layer or a carbon layer without removing the unremoved photosensitivity. a step of removing a film and a graphite layer or a carbon layer deposited on the photosensitive film, a light-shielding portion made of a graphite or carbon layer on the transparent substrate;
A method for manufacturing a light control filter, characterized in that a mesh-like pattern is formed by a light-transmitting portion without any of these layers.