JPH03243902A - Durable color image plate - Google Patents

Abstract

PURPOSE:To obtain a durable color image plate by forming a transparent protective layer having high durability on resolving dots having the three primary colors on a substrate and further forming a transparent sheet having high durability as a protective cover. CONSTITUTION:A lift-off layer 21 and a photoresist layer 22 are successively formed on a substrate 11 and the layer 22 is imagewise exposed and developed. The disclosed part of the layer 21 is removed with an etching soln., the photoresist is removed and an interference filter layer 61 is formed on the entire surface of the substrate 11 so as to coat the dot image-shaped lift-off layer 51. The substrate 11 is then immersed in a soln. etching the layer 51 but not etching the filter layer 61 to obtain a dot image 71 of the interference filter. A dot image 81 having the second color and a dot image 91 having the third color are formed in the same way and the entire surfaces of the images are coated with a protective layer 13. A durable color image plate is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color durable image plate having extremely high resistance to abrasion, corrosion resistance, and mechanical durability.

<Prior art and its problems> It is considered difficult for conventional color photographs and color printing to withstand storage for more than several hundred years under normal environments.

In addition, it generally had a heat resistance of only about 200'C. As a special type of printing, color printing using pigment ink on ceramics is known, but the color tone and resolution were poor and the color images were inferior. Furthermore, heat resistance, corrosion resistance, and maple-like durability were insufficient, and they were susceptible to damage in earthquakes, fires, and the like.

<Object of the Invention> Therefore, the object of the present invention is to provide a durable color image plate (Col.
or Duragraph).

<Means for Achieving the Invention> Among the inventions disclosed in this application, a brief overview of typical inventions is as follows.

That is, a highly durable substrate is used, and the color image formed thereon is composed of successively superimposed separated halftone dot images of the three subtractive primary colors, which are extremely durable. In addition to the three subtractive primary colors, a black halftone image may be superimposed. The four colors may be provided in any order.

Additionally, if desired, a highly durable transparent protective layer is provided over the halftone image.

Instead of providing a protective layer, or after providing a protective layer, a transparent and highly durable plate may be attached as a protective cover by adhesives, screws, etc.

<Specific Description> In the following figures, the dimensions of each layer are different from the actual dimensions, and some parts are extremely exaggerated.

FIG. 1 shows a color durable image plate of the present invention (Color Dur
In the figure, 11 is a highly durable substrate, 12 is a highly durable color image layer, 1
3 is a highly durable transparent protective layer.

In the present invention, "high durability" refers to extremely high heat resistance (withstanding temperatures of around 1000°C or higher) and extremely high corrosion resistance (not easily attacked by chemicals, solvents, etc.). It also means that it does not change in quality due to air or moisture even after long-term storage), has high mechanical durability, is hard to get scratched, hard to break, hard to deform, etc.

Specific examples of the highly durable substrate 11 include transparent ceramics such as silica, alumina, titania, zirconia, and beryllia; alumina, mullite, steatite, and other white ceramics; niobium-based alloys, molybdenum-based alloys, tantalum-based alloys; Metals such as tungsten-based alloys, chromium-based alloys, nickel-based alloys, cobalt-based alloys, and other super-metallic alloys; super-durable materials such as metal-ceramic laminates and sandwiches.

The appropriate thickness of the substrate 11 is about 0.1 mm to several tens of mm.

The suitable size of the substrate 11 is from several to several 103, but it is not limited to this range and may be even larger and thicker. It may also be smaller.

The end face of the substrate 11 is preferably chamfered.

A specific example of the highly durable color image layer 12 is a so-called interference filter in which a large number of highly durable, transparent thin layers with large refractive index differences are alternately laminated. Typical examples of materials include, but are not limited to, titanium dioxide as a high refractive index material and silicon dioxide as a low refractive index material. For example, alumina is used as the low refractive index material, and zirconia, cerium dioxide, etc. are used as the high refractive index material.

Specific examples of the highly durable transparent protective layer 13 include silica, alumina, titania, beryllia, and zirconia.

Next, a color durable image plate of the present invention (Color Durag)
raph) will be explained below.

The color durable image plate of the present invention is manufactured by photolithography. Photolithography methods include an etching method and a lift-off method, and either method can be used.

With reference to FIGS. 2 to 9, the color durable image plate of the present invention (
A manufacturing method using the lift-off method for Color Duragraph will be explained. The processes shown in FIGS. 2 to 7 are the so-called lift-off method.

FIG. 2 shows a cross-sectional view of a structure in which a lift-off layer 21 is provided on a substrate 11, and a photoresist layer 22 is further provided thereon. The surface of the substrate may be mirror polished or light scattering.

Specific examples of the lift-off layer 21 include aluminum, copper,
Examples include metals such as nickel and chromium. A requirement for lift-off layer 21 is that the etchant for lift-off layer 21 does not dissolve or alter interference filter layer 12. It is desirable that the thickness of the lift-off layer 21 be approximately the same as the thickness of the interference filter layer 12, but it is not essential.

The photoresist layer 22 may be of either a negative type or a positive type, which are well known in the field of semiconductor manufacturing. Known techniques are also used for the formation method, exposure method, development method, etc. of the photoresist layer.

FIG. 3 is a cross-sectional view of the photoresist layer after image exposure and development of the photoresist layer. 31 is a portion where the photoresist is dissolved and removed by development of the photoresist layer and the lift-off layer is exposed, and 32 is a portion where the photoresist remains. Prior to imagewise exposure of the photoresist layer, a known pre-beta may be performed. Image exposure to the photoresist layer can be carried out by a contact exposure method in which a photomask is brought into close contact with the photoresist layer and uniformly irradiated with JV light, or by exposure to the photoresist layer through a projection optical system using the photomask as an original image. A projection method may also be used. Alternatively, a method may be used in which the photoresist layer is directly scanned and exposed with a laser beam, an electron beam, or the like, without using a photomask.

A photomask uses a color scanner to separate color originals such as color photo prints, color slides, color negatives, and color prints to obtain black and white dot separation films corresponding to cyan, magenta, and yellow, which are then used as is. A photomask can be obtained by enlarging, reducing, etc. Photomasks can also be obtained by camera plate making without using a color scanner.

In the present invention, the transparency of the cyan, magenta, and yellow halftone dots is very high, so there is no need for a black plate.

FIG. 4 shows a state in which the exposed portion of the lift-off layer 21 has been removed by the lift-off layer etching solution, exposing the underlying substrate surface. 41 is a portion where the surface of the substrate is exposed. In addition to chemical etching, dry etching may be used to remove the lift-off layer.

FIG. 5 shows the photoresist remaining on the lift-off layer removed. 51 is a lift-off layer remaining in the form of a halftone image. The photoresist is removed by a known method.

FIG. 6 shows a state in which an interference filter layer 61 is then provided over the entire surface. The interference filter layer can be formed by vacuum evaporation, sputtering, ion blating, CVD,
This is carried out by a known method such as a sol-gel method. The interference filter layer is made by alternating two materials with significantly different refractive indexes.
It is formed by providing multiple thin layers. Examples of substances with a large difference in refractive index include silicon dioxide and titanium dioxide. The thickness of the thin layer and the number of layers are determined by a known calculation method according to the spectral characteristics of the filter (see Examples below for specific values).

Next, if the product in the state shown in FIG. 6 is immersed in a lift-off layer etching solution that does not attack the interference filter layer, the lift-off layer will be dissolved and removed, and the interference filter layer above it will fall off. A halftone image of the interference filter is obtained as shown in FIG.

71 is a halftone dot portion, and 72 is a non-dot portion. When removing the lift-off layer, applying ultrasonic vibration can effectively remove the lift-off layer.

Although the method for manufacturing the first color image using the lift-off method has been described above, an etching method may be used instead of the lift-off method.

In this way, a halftone image of the first color (for example, cyan) is obtained.

Once the first color is formed, it is desirable to provide a transparent intermediate layer over the entire surface. The reason for this is that if the second color is provided directly on top of the first color, interference will occur between the two and the colors may be different from those of each color alone. The middle layer is omitted in the figure.

The thickness of the intermediate layer is preferably in the range of a fraction of a meter to several μm,
It is desirable that the thickness be at least several times that of the constituent films of the multilayer interference film.

For example, about 0.2 to about 1 μm is appropriate.

Methods for providing the intermediate layer include vacuum evaporation, sputtering, CVD, sol-gel method, and the like.

The second and subsequent colors are provided in the same manner as the -th color.

Next, a lift-off layer is provided on the entire image surface of FIG. 7 via an intermediate layer (not shown), and a photoresist layer is further provided on the lift-off layer. Below, the process is exactly the same as in Figures 2 to 7 (the second color photomask is used. Also, the halftone dot image of the first color and the photomask of the second color are positioned so that the images do not deviate). As a result, a halftone image 81 of the second color is formed as shown in FIG. 8.

In addition, in FIG. 8, dot 8 is located at the edge of dot 71.
1 changes suddenly and discontinuously, but in reality they are smoothly connected. The same applies to the next FIG. 9.

An intermediate layer is also provided between the second color and the third color as described above.

Then, in exactly the same manner as in the case of the second color, a halftone dot image of the third color is formed. FIG. 9 shows a state in which a protective layer 13 is provided on the entire image surface after forming a third color halftone image 91. If unevenness occurs on the surface of the protective layer, it is desirable to flatten the surface by polishing. The protective layer 13 is formed by vacuum evaporation, sputtering, ion blasting, or CVD.

This is carried out by a known method such as a sol-gel method.

The color durable image plate described above has a specific gravity higher than that of water.

Because they are so large, if they encounter water damage such as a flood, they may sink to the bottom of the water or become buried in the soil, and may become lost.

Another aspect of the present invention is a color durable image plate that forms a highly durable color image on a highly durable substrate with a low specific gravity and has an overall specific gravity of less than 1. A highly durable color image is provided in the same manner as described above. A durable transparent protective layer is also provided in the same manner as described above.

As the substrate having high durability and low specific gravity, a closed foam body of metal or ceramics, an airtight hollow body of metal or ceramics, etc. are used.

Example 1 An artificial quartz plate (thickness: 5 mm, size: 4 x 5 inches, mirror polished on both sides) was used as a substrate. Copper was vacuum deposited on one side of the substrate to a thickness of about 1 μm. A coating film of positive photoresist (manufactured by Tokyo Ohka Co., Ltd., trade name 0FPR-800) was provided on this copper layer so that the dry thickness was about 1.5 μm, and prebaked at about 85° C. for 30 minutes.

A color slide with a size of 4 x 5 inches was used as an original, and a color scanner was used to scan the three primary colors (R, G).

It was resolved into a halftone resolution negative film (screen line count: 175 lines/inch, screen size: 4 x 5 inches) corresponding to B). In this way, cyan, magenta, and yellow photomasks were obtained.

Of the above photomask, the cyan halftone resolution negative was brought into close contact with the above photoresist layer so that the image surface was in contact with the photoresist layer, and ultraviolet rays were frequently irradiated on the entire surface through the photomask. ), product name: NMD
-3) When the photoresist layer was developed,
The photoresist in the portion (transparent portion) corresponding to the non-halftone dot portion was removed. The thus obtained photoresist pattern was post-baked at approximately 75° C. for 20 minutes to improve its durability against subsequent etching treatment, and then etched with an etching solution (a mixed aqueous solution of ferric chloride and hydrochloric acid). However, the copper in the area where the photoresist was removed was dissolved and removed, exposing the surface of the substrate in that area. After washing with water, the resist remaining on the copper was removed by immersion in acetone, washing with ethanol, further washing with water, and drying to obtain a copper halftone dot resolution negative pattern.

Next, on the entire surface of the copper halftone dot separation negative image for cyan,
A cyan interference filter layer was provided as follows. Titanium dioxide and silicon dioxide were alternately deposited by sputtering (titanium dioxide was provided first. The thickness of each titanium dioxide film was 71.7 nm.

A total of 11 layers of silicon dioxide (112.2 nm) were provided. 1
The total thickness of one layer was approximately 0.99 μm. When this image plate was immersed in the copper etching solution mentioned above and ultrasonic energy was applied, the interference filter layer in the area where copper was present was removed, and a cyan halftone image was obtained.

On the entire surface of the cyan halftone image thus obtained, silicon dioxide was provided as an intermediate layer to a thickness of about 0.4 μm by sputtering. Next, copper is vacuum-deposited to a thickness of about 1 μm on top of that, and then a photoresist is applied on top of it as described above, and magenta halftone dots are formed by aligning with the cyan halftone image using the same process as described above. An image was formed. However, a magenta dot resolution negative was used as the photomask, and the interference filter layer was made of titanium dioxide with a thickness of about 58.7 nm and silicon dioxide with a thickness of about 91.8 nm, for a total of 11 layers. The thickness of the 11 layers was approximately 0.81 μm.

Next, an intermediate layer of silicon dioxide with a thickness of about 0.4 μm was provided on the entire surface, and a yellow halftone image was similarly formed thereon in alignment with the above halftone image. However, a halftone resolution negative for yellow is used as a photomask, and the interference filter layer is made of titanium dioxide with a thickness of approximately 46.7 nm and silicon dioxide with a thickness of approximately 73.1 nm, for a total of 11 layers (thickness of approximately 0.65 μm).

In this way, a highly durable halftone color image was obtained, but
In order to further improve durability, a protective layer of transparent silica is applied by sputtering to the entire surface of the halftone dot image.
The protective layer was formed to a thickness of 0 μm, and the surface was polished to a thickness of about 5 μm.

The transparent color durable image plate obtained in this way is
It was able to withstand temperatures of 1000°C in the atmosphere.

<Example 2> A white alumina substrate with a thickness of about 3+ nm and a size of 4 x 5 inches and mirror-polished on one side was used as the substrate, and copper was vacuum-deposited on the mirror side to a thickness of 1 μm in exactly the same manner as in Example I. , and then a photoresist was applied over it.

A photomask was produced as follows.

Using a color scanner, a 4-color (magenta, cyan, yellow, black) separated dot film (screen line count: 200 lines/inch, size 4 x 5 inches) was produced from a 4 x 5 inch color slide.

Cyan, magenta, and yellow interference filter halftone dot images were formed in the same manner as in Example 1 using the thus obtained photomask. Then, a halftone dot image (black image) of silicon carbide was formed in the same manner.

The silicon carbide layer was provided by sputtering to a thickness of about 0.5 μm.

A protective layer of transparent silica was then applied to a thickness of about 5 μm to obtain a color durable image plate.

The color durable image plate withstood temperatures of 1200°C.

<Example 3> A closed-cell foamed ceramic (manufactured by Central Glass Co., Ltd., trade name: CERAPHOME) with a thickness of about 25 mm and a size of 4 x 5 inches was used as a substrate, and the same color durable image board as in Example 2 was placed on top of this. (However, the thickness of the alumina substrate is 2 mm.
) were welded using cement. Although the thus obtained color durable image plate is inferior in heat resistance and mechanical durability to that of Example 2, it has the characteristic that it floats on water and will not be submerged even in a flood.

If you own a device in the form of Example 2 and a device in Example 3 that have the same image at the same time, the probability that you will survive a disaster even if you encounter a disaster increases by -0.

<Effects of the Invention> Color durable image plate (Color Dura) according to the present invention
graph) is extremely durable and can withstand heat, light, chemicals,
It is incomparably more stable against moisture, mechanical shock, etc., and can be called a true color durable image plate. Under normal circumstances, it can last for thousands or tens of thousands of years. Even in the event of a natural disaster, there is a very high chance that it will survive.

Furthermore, the image can be reproduced or read out with the naked eye or with a simple optical device, without the need for special reproduction or reading equipment.

[Brief explanation of drawings]

FIG. 1 shows a color durable image plate (ColorD) according to the present invention.
cross-sectional views of specific examples of uragraph), Figures 2 to 9
The figures up to the figures illustrate a specific example of the manufacturing method of the color durable image plate of the present invention, and Figure 2 is a cross-sectional view of a structure in which a lift-off layer and a photoresist layer are provided in this order on a substrate, and Figure 3 is a cross-sectional view of a structure in which a lift-off layer and a photoresist layer are provided in this order on a substrate. 4 is a sectional view after the lift-off layer has been etched, FIG. 5 is a sectional view after the photoresist has been removed, and FIG. Fig. 7 is a cross-sectional view after removing the interference filter layer, Fig. 8 is a cross-sectional view after the second interference filter image is provided, and Fig. 9 is a cross-sectional view after the third interference filter image is provided. 1 is a cross-sectional view of a color durable image plate having an interference filter image formed thereon and further provided with a transparent protective layer thereon; FIG. In the figure, 11...--board 12...
Color image layer 13...Transparent protective layer 21
...... Lift-off layer 22 ... Photoresist layer 31 ... Photoresist removal section 32 ...
- Photoresist remaining portion 41...Lift-off layer removed portion 51...Lift-off layer remaining portion 61...Interference filter layer

Claims (2)

[Claims] (1) A color image with gradations is formed on a durable substrate by halftone dots of the three subtractive primary colors, and the halftone dots of the three subtractive primary colors are interference filters made of durable materials. Features a color durable image board. (2) A color durable image plate characterized in that a durable transparent protective layer or a protective cover is provided on the interference filter layer according to claim (1).