JPS6135523B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing an optical filter.

Conventionally, when creating a color filter for a television camera, for example, it is necessary to selectively form a dyeing pattern in a minute area of 5×10 μm with colors exhibiting necessary spectral characteristics. Figure 1 shows the conventional manufacturing method of a three-color color filter using this dyeing method.
There is a method shown in FIG. The method shown in Figure 1 is
A photoresist film 2 is formed on a transparent glass substrate 1 by adding ammonium chromate to gelatin that can be dyed to give negative photosensitive characteristics.
selectively irradiates the film 2, leaves only the irradiated part of the film 2, removes the rest, and dyes the remaining part to obtain a dyeing pattern 5 that becomes one color of the color filter b.

Then, after forming an intermediate film 6 to protect the pattern 5 from the next dyeing, the above-described photoresist film formation and mask exposure are repeated again to form a dyed pattern 7 of a different color adjacent to the pattern 5 through the intermediate film 6. do. Furthermore, the same process is repeated again to form a dyed pattern 9 having a different color from the patterns 5 and 7 via the intermediate film 8. In this way, a color filter is created by sequentially stacking red, green, blue, etc. dyeing patterns.

In the method shown in Fig. 1, three gelatin coatings, three dyeing shape processing steps, and two interlayer film formation steps are required in addition to the dyeing steps, and fine particles are removed.
This is extremely disadvantageous for manufacturing large filters.

The method shown in FIG. 2 involves coating a positive photoresist 12 on a dyeing film 11 on a transparent glass substrate 1, selectively exposing it to light 14 using a mask 13, and opening a window in the resist 12 on the dyed area. Then, the dyeing film 11 in that portion is dyed to form a dyeing pattern 15 b. Thereafter, the resist pattern 12 is removed and the above steps are repeated. That is, a new resist pattern 16 is formed, and a dyed pattern 19 having a different color from the pattern 15 is formed by irradiating light 18 through a mask 17 and dyeing. Then, a new photoresist 20 is formed again, and light 22 is irradiated through the mask 21 to form a dyed pattern 23 in the same manner (d).

The method shown in Figure 2 also requires many steps of resist application and window opening, and during dyeing, the dye diffuses to a larger area than the opening area of the resist, which is disadvantageous for forming fine dyed patterns. be.

The present invention uses a film made of a photosensitive organic coloring material, generates a functional group capable of fixing a colored substance on the material itself in the light irradiated part of the film, and reacts the colored substance and the functional group to form a functional group in the light irradiated part. For example, when manufacturing a mosaic color filter with multiple colors, high resolution (micron region) is used.
It is possible to form an image on a flat plate with only ultraviolet exposure using a photomask,
The process is simple. In the dye-based coloring method, the coloring density can be controlled by the amount of light irradiated onto the photosensitive coloring material base material, and it is possible to easily perform coloring with reproducibility.

That is, in the present invention, by performing high-precision exposure using a combination of ultraviolet light and a photomask, fine partial coloring in the micron region is possible. Therefore,
By applying the optical filter manufacturing method of the present invention, color filters (mosaic images of several colors) required for image pickup tubes or image pickup plates for color television cameras can be easily and highly accurately created on a flat plate.

A specific implementation method of the present invention and its principle will be described below.

As an example of a photosensitive organic coloring material, when a thiocyanatoacetyl styrene copolymer is irradiated with ultraviolet light with a wavelength shorter than 350 nm, the thiocyanatoacetyl groups in this copolymer are rearranged to form isothiocyanate as shown below. It becomes a toacetyl group.

The inventors have discovered that this isothiocyanatoacetylstyrene copolymer can be dyed with cationic dyes in the presence of alkali or base. The mechanism is thought to be as follows.

〓〓〓
That is, isothiocyanatoacetylstyrene forms an anion seat with an alkali or base, and a so-called functional group capable of fixing a dye is generated, which reacts with a cationic dye and can be dyed.

The specific coloring (staining) conditions are 7 wt% of thiocyanatoacetylstyrene and acetylstyrene copolymer (20 mol% of thiocyanatoacetylstyrene).
A film (approximately 40 μm thick) is made on a glass slide from a tetrahydrofuran solution. This film is irradiated with light for a predetermined time using a Ushio UM102 high-pressure mercury lamp (utilizing 310 nm light using a UV31 filter) while maintaining a distance of 10 cm. Note that it is appropriate that the irradiation light has a wavelength of 350 nm or less.

The irradiated film was mixed with 50 ml of a 0.5 wt methanol-dioxane solution of fuchsin (volume ratio of methanol and dioxane 3:1) and 0.3 ml of triethylamine.
After immersing in a dye bath for 10 seconds, wash with water and dry. As a result, only the exposed areas are colored red by fuchsin.

The relationship between irradiation time and isothiocyanate group formation is
As shown in Figure 3. A2045 in the figure is the absorbance at 2045 cm ^-1 of the infrared absorption spectrum, -N
It shows the absorption intensity based on the formation of =C=S. A1560 also has an infrared absorption spectrum.
It is the absorbance at 1560 cm ^-1 (based on benzene rings) and is used as a standard for the amount (thickness) of the film base material. From the data in FIG. 3, the amount of light-induced rearrangement of thiocyanatoacetyl groups to isothiocyanatoacetyl groups is proportional to the irradiation time.

The amount of isothiocyanate groups and the dyeing density of the dyed film were measured using absorbance A555 at 555 nm. The relationship is shown in FIG. This result shows that the staining density increases in proportion to the content of isothiocyanate groups.

From these data, the dyeing density of the thiocyanatoacetylstyrene copolymer can be controlled by the amount of light irradiation. Of course, the dyeing time and dye concentration can also be adjusted, but the final density can be determined by the amount of light irradiation regardless of these conditions.

Fuchsin (red) as a cationic dye Methylene bull (blue) Azure A (green) 〓〓〓
It could also be dyed.

Note that other colors such as cyan, magenta, yellow, etc. can also be used as the dye.

In addition, examples of compounds containing a thiocyanatoacetyl group that can be used as photosensitive coloring materials include the following compounds (a) to (d) and derivatives thereof. Derivatives include polymers or copolymers.

(a) Thiocyanatoacetylbenzene (b) Thiocyanatoacetylstyrene (c) Thiocyanatoacetylethylene (d) Vinyl thiocyanatoacetate In addition, when used as a photosensitive coating, the above
(A) to (D) may be used by being dispersed in a binder.

Further, when the photosensitive coloring material is in a polymeric form such as a polymer or a copolymer, it can be used as a photosensitive coloring material having film-forming properties.

A method according to an embodiment of the present invention for creating a color filter for a television camera using the above coloring method will be explained with reference to FIG. First, a colorless and transparent film with a thickness of about 40 μm made of a photosensitive organic coloring base material 31 made of a thiocyanatoacetylstyrene copolymer is coated on a glass substrate 30 that will serve as a transparent base, and an opaque area (hatched area) is formed. After selectively irradiating ultraviolet light 33 using a photomask 32 having a photomask 32 to cause the above-mentioned reaction in the light-irradiated area, the substrate 30 is immersed in the above-mentioned dye bath containing the dye, and the material 31 is irradiated with light. Only the area is dyed to form a red dyeing pattern 34 of, for example, 10 μm square c.

Then, using another photomask 34,
Ultraviolet light 3 is applied to a part of the material 31 that is different from the pattern 34.
6 is selectively irradiated d to cause the above-mentioned reaction, and then dyed with a different color from that of the pattern 34 using a dye bath of a different color. In this way, a dyeing pattern 37 different from the pattern 34, e.g., blue, is formed.

Similarly, after selectively irradiating ultraviolet light 39 to parts of the material 31 different from the patterns 34 and 37 using a mask 38, (g) dyeing only the irradiated area to form, for example, a green dyeing pattern 40;

Thus, dyeing patterns 34, 3 for color filters consisting of red, blue and green respectively, for example.
A color filter having a color filter of 7.40 is manufactured. According to the method shown in Fig. 5, the base material for photosensitive organic coloring is selectively irradiated with light, and only the light irradiated area can be colored, and a colored pattern is formed on the light irradiated area, so that the base material is simply irradiated with light. A colored pattern on a filter can be formed simply by using selective exposure and dyeing steps. Therefore, when manufacturing a color filter having a coloring pattern of multiple colors, it is necessary to
This method does not require multiple dyeing film coatings and processing, or multiple resist coating, development, and resist removal steps, and can easily produce highly accurate color filters with a small number of steps.

Although the above description has been made regarding color filters, the present invention can also be applied to other optical filters, and other colored patterns such as cyan, magenta, and yellow can be similarly formed.

As described above, according to the method of the present invention, a mosaic color filter can be created directly on a photosensitive substrate by ultraviolet irradiation using a photomask and a dyeing operation, and the number of steps can be reduced compared to the conventional method. . Furthermore, in the present invention, since a single-layer photosensitive colored substrate is directly dyed, a fine image with high resolution (in microns) can be formed by using a high-precision light irradiation device. In addition, in addition to obtaining a colorless and transparent base material, the coloring density can be controlled by adjusting the amount of light irradiated onto the photosensitive colored base material, making it easy to perform coloring with reproducibility and achieving high-precision, fine-grained coloring. This greatly contributes to the production of patterned optical filters.

[Brief explanation of the drawing]

Figures 1 a to d and 2 a to d are manufacturing process diagrams of conventional color filters, Figure 3 is a diagram showing the relationship between the irradiation time of ultraviolet holes and the production of isothiocyanate groups, and Figure 4 is the amount of isothiocyanate groups. Figures 5a to 5g are diagrams showing the manufacturing process of a color filter according to an embodiment of the present invention. 30... Glass substrate, 31... Photosensitive organic colored base material, 32, 35, 38... Photomask,
33, 36, 39... Ultraviolet light, 34, 37, 40
...dyeing pattern. 〓〓〓〓

Claims (1)

[Claims] 1. A film made of a photosensitive organic coloring material is formed on a transparent substrate, and by irradiating the film with light, the light irradiation part generates a functional group capable of fixing a colored substance on the material itself. A method for producing an optical filter, characterized in that the colored substance and the functional group are reacted to color only the light-irradiated portion. 2. The method for producing an optical filter according to claim 1, wherein the photosensitive coloring material contains a thiocyanatoacetyl group. 3. The method for manufacturing an optical filter according to claim 1, wherein the coating is selectively irradiated with light. 4. The method for manufacturing an optical filter according to claim 2, in which a photomask is used for selective light irradiation. 5. A step of forming a film made of a photosensitive coloring material on a transparent substrate, and a step of selectively irradiating a first region of the film with light to generate a functional group and dyeing the first region. and a step of selectively irradiating light to a second region other than the first region of the coating to generate a functional group, and dyeing the second region a color different from the first region. A method for manufacturing an optical filter, comprising: 6. The method for producing an optical filter according to claim 5, wherein the photosensitive coloring material contains a thiocyanatoacetyl group.