JPH04147149A - Durable image plate - Google Patents

Abstract

PURPOSE:To store an image permanently without deterioration in picture quality by recording a visible image as a dot image on a substrate by photolithography by using an image forming material which has large heat resistance, anticorrosiveness, and mechanical durability and is different from the substrate. CONSTITUTION:On the substrate 14 made of a material with large heat resistance, anticorrosiveness, and mechanical durability, the visible gradational image is recorded as the dot image by photolithography by using the image forming material which has large heat resistance, anticorrosiveness, and mechanical durability and is different from the substrate, and the optical contrast between a dot part 31 and a non-dot part 32 is made sufficiently large to the extent of normal printed matter. Consequently, the real durable image plane which has large durability and is stable to heat, light, chemicals, moisture, a mechanical shock, etc., is obtained.

Description

[Detailed Description of the Invention] <Related Field of the Invention> The present invention provides an extremely durable image that can be permanently stored without deterioration of image quality, and that is extremely beautiful even when viewed directly with the naked eye. The present invention relates to a durable image board that can be used.

<Background of the Invention> The main materials of commonly used silver salt photographic media, printed matter, magnetic recording media, optical recording media, etc. are organic materials.
Poor heat resistance, corrosion resistance, mechanical durability, etc. for example,
Black and white prints, black and white films, color prints, color films, magnetic tapes, optical cards, optical discs, etc. are not flame resistant.

It is also attacked by strong chemicals and dissolved in certain solvents. Furthermore, it may be torn, torn, scratched, wrinkled, or stretched due to external mechanical forces. Furthermore, black and white prints, color prints, color films, etc. may change color or fade over time.

Silver halide microfilm has been proven to have a shelf life of 100 years, but there are still questions about the shelf life of digital records. Furthermore, it is doubtful whether the digital playback devices currently in use will still exist several decades or even hundreds of years from now. Since analog visible images can be viewed directly with the naked eye and easily reproduced with simple optical magnification or reduction equipment, there is no fear that reproduction equipment will not exist in the future.

In the field of printing, lithograph printing, gravure printing, planographic printing, etc. are known.

Lithograph printing is a historical method in which a letterpress is created by hand engraving a stone slab, which is then dipped in ink and transferred to paper. Therefore, precise images could not be obtained, and the plates were also brittle and weak.

Furthermore, the printed image had low contrast and no gradation, and could not be used for viewing purposes.

Gravure printing uses a plate in which dots of a constant size are formed in a copper cylinder and the depth increases depending on the image density. Even when looking at the plate directly with the naked eye, there was almost no gradation or contrast, so it could not be used for purposes of appreciation.

Of the lithographic printing plates, 28 plates are generally those in which the surface of an aluminum plate is anodized to form a new water-based surface, and a new oil-based resin image is formed thereon. This has low heat resistance and low corrosion resistance. Among the planographic printing plates,
Is it something special called a bi-metal version or a tri-metal version? A bimetal plate is an image of fresh water-based chromium formed on a fresh oil-based copper or stainless steel substrate. Tri-metal plates have a layer of fresh oil-based copper on an iron substrate, and a new water-based chromium image is formed on top of that. Both plates have fairly high heat resistance, but copper is used. As a result, heat resistance, corrosion resistance, and mechanical durability were all inadequate.

In the case of printing plates, there are no particular requirements for heat resistance or corrosion resistance, so super heat-resistant metals are not used. In the case of the above-mentioned bimetals and trimetals, stainless steel is also common and does not have very high heat resistance. Furthermore, the plate is not meant to be viewed directly with the naked eye, but rather is used to apply ink and transfer it to paper, so the image on the board may have very small gradation, contrast, and last. In fact, lithographic printing plates, gravure printing plates, bimetallic and trimetallic printing plates are not as beautiful as printed matter when viewed with the naked eye.

Even if these printing plates were to be used as durable image plates, if they were exposed to high temperatures in the air for long periods of time, the metal in both the image and non-image areas would oxidize and become colored, further reducing the contrast of the image. As a result, most of the beauty of the image is lost.

Printed plates are not viewed on their own, but rather on the printed matter that is printed using the plate. Therefore, the plate itself does not have to be beautiful, nor is it required to be heat resistant or corrosion resistant.

In addition, there are designs etched onto stainless steel plates.
It is known to be used as wall decoration and information boards for tourist spots. Among these, those in which a design is simply etched onto a stainless steel plate do not provide a good image because the contrast between the design and the background is small. In contrast, after providing a colored film on the surface of the stainless steel plate,
Etched designs can provide high contrast, but when exposed to high temperatures in the air for long periods of time, the etched areas gradually become colored, which also reduces the contrast of the image.

In addition, in conventional printing plates, color-separated plates were prepared separately, and there was no idea that one color image could be recorded as multiple images separated into multiple colors on a single plate. . In particular, there was no idea to separate the colors into small sizes and record them on a hand-sized or cabinet-sized board.

BACKGROUND OF THE INVENTION Conventionally, examples are known in which characters are etched onto a metal plate such as stainless steel using a chemical etching method to produce a name plate, and simple designs are etched into decorative items.

Letters and simple designs made using this method can be used for some purposes of appreciation, but even if you convert a photograph into a halftone image using this method, you will not be able to obtain sufficient contrast or gradation.
In addition, the background was not white like in the photo, and the dark areas were not black like in the photo, so it was impossible to appreciate it as a photo.

In addition, nameplates and ornaments engraved on conventional metal plates have a much higher specific gravity than water, so if they encounter water damage such as a flood, they may sink to the bottom of the water or be buried in the soil, causing them to go missing. was there.

<Object of the Invention> The present invention has been made in view of the above background, and the first object of the present invention is to have extremely high heat resistance, corrosion resistance, mechanical durability, etc., and to provide permanent image quality without deterioration of image quality. To provide a durable image board capable of storing images for a long time.

A second object of the present invention is to provide a durable image plate that will not be submerged even if it is exposed to water due to water damage.

A third object of the present invention is to provide a set of durable image plates in which at least one of the plates will survive even if exposed to high heat such as a fire, mechanical shock such as an earthquake, water damage, etc.

A fourth object of the present invention is to provide a durable image plate that is unlikely to run out of playback equipment even in the distant future.

A fifth object of the present invention is to provide a durable picture plate having a beautiful image that by itself stands up to the purpose of visual viewing.

<Disclosure of the Invention> In the first embodiment of the durable image plate of the present invention, a material having high heat resistance, corrosion resistance, and mechanical durability is provided on a substrate made of a material having high heat resistance, corrosion resistance, and mechanical durability. Generally speaking, a visible image with gradation is recorded as a halftone dot image using a photolithography method using an image forming material different from the substrate, and the optical difference between the halftone dot portion and the non-dot portion is recorded. It is characterized by a contrast that is sufficiently large as that of ordinary printed matter.

Preferably, the optical density difference between the halftone dot area and the non-dot area with respect to white light is 0.9 or more in the case of a reflection image and 1.4 or more in the case of a transmission image. The same applies to the following aspects.

A second aspect of the durable image plate of the present invention is that the same visible image with gradation is formed on a metal substrate having high mechanical durability and a durable ceramic substrate having high heat resistance. A durable image that is recorded as a halftone dot image by photolithography using an image forming material different from that of the substrate, and has a sufficiently large optical contrast between halftone dot areas and non-dot areas. Consists of at least two types of boards.

A third aspect of the durable image plate of the present invention is to provide a visible image with gradation on a highly durable metal or ceramic closed cell foam substrate and/or a highly durable metal or ceramic hollow body substrate. is an image-forming material different from that of the substrate, which has great heat resistance, corrosion resistance, and mechanical durability, and is recorded as a halftone image by photolithography, and has a halftone dot area and a non-dot area. has a sufficiently large optical contrast and an overall specific gravity of less than 1.

High durability here means that although the heat resistance, corrosion resistance, and mechanical durability are not as great as in the above two aspects, the durability is incomparably greater than that of conventional photographs and printing plates. That's true.

A fourth aspect of the durable image plate of the present invention is comprised of at least three types, the durable image plate of the second aspect and the durable image plate of the third aspect.

The gradated visible image of the durable image plate of the present invention is expressed as a monochrome image.

When the original visible image with gradation is a color image, the halftone dot image is composed of a plurality of color-separated halftone dot images separated into a plurality of colors. Color separation halftone images may include separation images for black plates, as in the case of four color separation images used in the field of printing.

The plurality of color separation halftone dot images may be formed on one substrate or on separate substrates. In this case, when looking at the color separated image directly, it is a beautiful monochrome image, but it is not a color image.

To reproduce a color image, each separated image must be aligned and projected onto a screen or printed.

As described later, it may be read with a scanner, displayed, or made into a hard copy.

It may also be printed by enlarging it on a color photographic material.

In order to improve the durability of the durable image plate of the present invention, a transparent protective layer having high heat resistance, corrosion resistance, and mechanical durability may be provided on the halftone image. When the substrate or image forming material has the property of being oxidized and colored at high temperatures, the effect of preventing oxidation and coloring by the protective layer is particularly large.

In the durable image board of the present invention, durable images may be formed on both sides of the durable substrate.

The durable substrate in the present invention does not necessarily have to be flat, as long as the image surface is flat, and the back surface may be curved or any other shape. Further, the surface on which the image is formed may be rectangular, disc-shaped, or any other arbitrary shape. It may be an artificial polyhedron such as a gemstone or a natural polyhedron such as a crystal.

The durable substrate in the present invention may be transparent or opaque.

The durable image of the present invention having various aspects as described above is named rDURAGRAPHJ.

The method for producing the durable image plate of the present invention includes a known photolithography process.

In the above manufacturing method, there are two methods for exposing the photoresist film. That is, there are two methods: one is to directly irradiate an energy beam modulated with a halftone dot image, and the other is to irradiate a photosensitive material such as a silver salt photosensitive material and then expose it using a photomask formed by developing the photosensitive material.

As a halftone image creation method, there has been a halftone technique (also called camera plate making) in which a contact screen is used to create a halftone image in the field of printing. Alternatively, a halftone image may be formed using a scanner.

Although the dither method is included in the present invention, the conventional halftone dot method (gradation is changed by changing the area of - halftone dots) is more desirable in terms of resolution.

It is desirable that the number of density gradations is 64 or more gradations, preferably 128 or more gradations, and more preferably 256 or more gradations.

Furthermore, the pixel density of the halftone dot image needs to be at a level sufficient to be viewed as a photographic image, and varies depending on the viewing means. When viewing directly with the naked eye, at least approximately 2
．． 5 lines/mm (5 dots/mm) or more, preferably about 5 lines/[+1111 (10 dots/mm) or more,
More preferably 8 lines/+nm (16dot/mm)
The above is desirable.

When enlarging and printing durable images, it is necessary to increase the density even further.

In the present invention, images with gradations refer to natural images such as photographs, printed images, computer graphics images, and combinations of these with character images, documents, etc.

It is preferable not to halftone text images, documents, line drawings, etc.

In the present invention, heat resistance refers not only to being placed in a high-temperature atmosphere, but also includes resistance to flames, that is, flame resistance.

In the present invention, corrosion resistance refers to properties that are resistant to deterioration, discoloration, dissolution, and other deterioration due to chemicals, solvents, air, moisture, etc., such as chemical resistance, solvent resistance, air oxidation resistance, and moisture resistance. means.

In the present invention, mechanical durability refers to abrasion resistance, properties that are not easily deformed by external forces (for example, not easy to bend), properties that are strong against impact, etc.

DETAILED DESCRIPTION> The durable image plate of the first aspect of the present invention and its manufacturing method will be described in detail below with reference to the drawings. For ease of understanding, the depth of recesses, the thickness of opaque parts, the thickness of photosensitive layers, the thickness of photoresist films, thin films, the thickness of protective layers, etc. are exaggerated in the drawings. ing.

Figure 1 shows the durable image plate (Durλgraph) of the present invention 1
FIG. 2 is a top view of one specific example of the present invention, and FIG. 2 is a cross-sectional view taken along the line A--A.

In FIGS. 1 and 2, 11, 12, and 13 are halftone dot images corresponding to visible color images with three gradations, respectively. The halftone image 11 is a three-color separation image 11-1.
11-2.113. Similarly, images 12 and 13 are three-color separation images 12-1.12-2.12-3.13-1.
Consists of 13-2.13-3. 14 is a flat substrate.

FIG. 3 is a partially enlarged cross-sectional view of a halftone dot image area, for example 11-1, in which numeral 30 is a halftone image area, with convex portions 31 (halftone dot portions, image forming material layer) and concave portions 32 (non-dot portions, image forming material layer). Dot part,
(substrate surface). 33 is a non-image area.

A photolithography method is applied to form the convex portions 31 and the concave portions 32.

The convex portion 31 is
and a method of forming the recess 32 will be explained.

FIG. 4 is a cross-sectional view of a state in which a durable thin film 41 made of a material different from the substrate 14 is provided on the substrate 14, and a positive photoresist film 40 is provided thereon by, for example, a spin cord method. It is.

FIG. 5 shows halftone dots corresponding to visible images on a photosensitive material 50 (consisting of a transparent substrate 52 such as a plastic film or glass and a photosensitive layer 51 provided thereon) for a photomask to create a photomask. This shows a state in which the photosensitive layer 5I is exposed in the form of a halftone image by irradiating the image-modulated energy beam 53. Specific examples of energy beams include laser beams, electron beams, and the like.

As specific examples of the photosensitive material, silver salt high-resolution films of wet development type or heat development type, dry plates, etc. are advantageously used. A photomask can be obtained by performing a development process after or simultaneously with exposure to an energy beam.

As a method for producing a photomask, in addition to the method of exposing each dot with an energy beam as described above, a method conventionally known in the printing field as a contact screen method, which will be described below, may be used.

For example, exposing a visible image through a contact screen placed in close contact with a photosensitive material such as lithographic film;
After development, a halftone image is obtained.

This may be used as a photomask, but in order to obtain a high-resolution photomask, this halftone image is exposed to high-resolution photographic film or a photographic plate using a high-precision reduction exposure device, and then developed. As a result, a high-resolution photomask can be obtained.

FIG. 6 shows a state in which a photomask 60 is overlaid on the material shown in FIG. 4, and ultraviolet rays 61 are uniformly irradiated onto the photoresist film 40 through the photomask 60 to form a latent image on the photoresist film. shows. At this time, it is desirable that the photoresist film 40 and the pattern retaining layer 62 of the photomask be placed in contact with each other.

The black portion 63 in the pattern holding layer 62 is a portion that absorbs ultraviolet rays 61, and the transparent portion 64 is a portion that transmits the ultraviolet rays.

Next, when the photoresist film 40 is developed, the portion of the photoresist film 40 exposed to ultraviolet rays is dissolved and removed as shown in FIG. 7, and the thin film surface of that portion is exposed (70) t.
, an unexposed area (71) remains. Next, the thin film 41 is chemically etched using an etching solution capable of etching it, or
Alternatively, the protrusions 31 are formed by etching the thin film 41 using a dry etching method such as sputter etching, ion etching, or plasma etching. If the substrate 14 and thin film 41 are metal, electrolytic etching can also be used.

Finally, if the remaining resist is removed by a known method,
A durable image plate as shown in FIG. 3 is obtained.

Next, a photolithography method that does not use a photomask will be explained.

By directly exposing the photoresist film 40 in FIG. 4 to light by modulating the energy beam that the photoresist senses with a halftone image converted from a gradated visible image, a halftone image is formed on the photoresist film. A latent image can be formed. Then, in the same manner as described in FIG. 7 and subsequent parts, the processes of developing the photoresist film, etching the thin film, and removing the remaining resist are carried out to form a halftone image area. in this way,
The photoresist film 40 needs to be sensitive to energy beams, and laser beams, electron beams, etc. are used. As the laser, an Ar laser, a He-Cd laser, etc. are used. The power of the laser beam is also required to be several mW to several tens of mW, which is enough to expose the photoresist.

For the photoresist, photomask, etching, etc., known materials and techniques used in photolithography for manufacturing semiconductor devices and printed circuit boards can be used.

As photoresists, there are two types of photoresists that can be used: positive type, in which exposed areas are easily dissolved in developer (solvent), and negative type, in which exposed areas are difficult to dissolve in developer (solvent).

Specific products include 0FPR-800 (positive resist) and 0νR83 sold by Tokyo Ohka Co., Ltd.
(negative resist), HPR-204 (positive resist) sold by Fuji Hunt Co., Ltd., and the SC series.

IC series, HR series, etc. (negative type), NPR-820 (positive type) sold by Nagase Sangyo Co., Ltd.
, NNR-732 (negative type), Hitachi Chemical Co., Ltd. UV resist RD-200ON (negative type), RG
-8040P (positive type), electron beam resist RE-50
00P (positive type) and others can be used.

As a photomask material, an emulsion type photosensitive material (for example, Kodak HR manufactured by Eastman Kodak Company) is used.
A photoresist film is provided on a hard mask (e.g., chrome mask blank, iron oxide mask blank, etc.), and pattern exposure is performed on the photoresist film by an appropriate method. For example, Scanning exposure may be performed with a laser beam or exposure may be performed using a pattern generator.Then, a hard mask is obtained by developing the photoresist film, etching the mask layer, and removing the remaining resist), film mask. (emulsion film, diazo film, etc.)
is used.

As the chemical etching liquid, a hydrofluoric acid-based etching liquid is used for quartz, a ferric chloride-based etching liquid is used for stainless steel, a cerium ammonium nitrate-based etching liquid is used for chromium, and a phosphoric acid-based etching liquid is used for alumina. Other known etching solutions may be used.

If chemical etching is not possible, known dry etching methods such as sputter etching, ion etching, and plasma etching can be applied.

If the substrate and thin film are conductors, electrolytic etching can be used. Electrolytic etching is accomplished by using the substrate to be etched as an anode, covering portions that are not desired to be etched with a resist, and then applying electricity in an electrolytic solution.

When forming an image using a material that is difficult to etch, a so-called lift-off method can be used instead of the above-mentioned normal etching method.

In the above manufacturing example, the image material (thin film 41) is not included in the photoresist film, but next, an example will be shown in which the image forming material is included in the photoresist film. Fine particles of metals, metal oxides, ceramics, etc. are dispersed in photoresist, and the photoresist film that is coated and dried is photosensitive like a normal photoresist film, and after image exposure, it can be developed. A relief image of the photoresist is formed. When this relief image is then exposed to high temperatures (approximately 500°C or higher) in the air, the photoresist evaporates and the fine particles or their oxides dispersed in the photoresist film remain in the form of an image as shown in Figure 3. A durable image board is obtained. If the type of fine particles is selected appropriately, an extremely durable image can be formed. For example, as fine particles, 0. O
Iron oxide, chromium oxide, noble metals of about 1 to 0.05 μm,
Silicon carbide or the like is used. In addition to these colored fine particles,
Colorless fine particles such as silica and alumina may be mixed.

This manufacturing method has the advantage of simplifying the manufacturing process, since the process of providing the thin film 41 and the etching process of the thin film 41 are also unnecessary.

In the example shown in FIG. 3, the halftone dot portions are made up of convex portions or concave portions, but they may be made of a completely flat surface without any uneven portions. This example will be explained below.

FIG. 8 is a cross-sectional view of a specific example of a durable image plate in which the dark and bright areas of the halftone image area are on exactly the same surface.

In the figure, for example, 81 is a dark area and 82 is a bright area. A method for obtaining the durable image plate of FIG. 8 will be described below.

FIG. 9 is an intermediate image plate for obtaining the durable image plate of FIG. To obtain the intermediate image plate shown in FIG. 9, one without the thin film 41 shown in FIG. 4 is prepared and the same method as shown in FIGS. 5 to 7 is applied thereto. At the stage shown in FIG. 7, the substrate 14 is exposed instead of the thin film 41. Then, the substrate 14 is etched,
After removing the residual resist, the intermediate image plate of FIG. 9 is obtained. 91 is a convex portion, and 92 is a concave portion. The substrate 1 is placed in the recess 92.
A substance 81 having a large optical contrast with respect to 4 is embedded.

A specific method for filling the recesses 92 is to apply a durable material to the entire surface of the durable image plate shown in FIG. At this point, polishing is stopped. Another method for filling the recesses 92 is to cover the protrusions 91 with a suitable resist and then apply plating, vacuum evaporation, sputtering,
There is a method in which a material other than the substrate 14 is deposited on the recess 92 to a thickness equal to the depth of the recess using a blue gel method or the like, and then the resist is removed.

A durable image plate with a flat surface without unevenness like this example,
This has the advantage that the surface is less prone to scratches.

The recess 92 may be filled to a halfway depth so that a depression remains.

The durable image plate of the present invention may have its surface protected with a transparent durable material. Transparent means being transparent to observation light, and does not necessarily have to be colorless and transparent.

FIG. 1O is a sectional view of a specific example of a durable image plate having the structure shown in FIG. 3, with a transparent durable protective layer 100 provided on the surface thereof. A durable image plate having the structure shown in FIG. 8 can also be provided with a protective layer. Specific examples of materials for the durable transparent protective layer +00 include silica, beryllia, alumina, titania, zirconia, and the like. The protective layer 100 can be provided by, for example, vacuum evaporation, sputtering, ion blasting, CVD, sol-gel method, or the like.

The thickness of the transparent protective layer is suitably in the range of a fraction of a micrometer to several tens of micrometers, but may be outside this range.

Specific examples of transparent durable substrates include silica, alumina, beryllia, zirconia, titania, and the like.

The image forming materials for the halftone dot portions 31 and 81 are as follows:
It is necessary to use metals (including metalloids) or ceramics with high heat resistance, corrosion resistance, and mechanical durability, and to have a large optical contrast with respect to non-dot areas. For a beautiful photograph, the optical density difference between dot and non-dot areas must be at least 0.9 for a reflection image and at least 1.4 for a transmission image.

The thickness of the durable image material is suitably in the range of a fraction of a micrometer to several micrometers, but may be outside this range.

Examples of durable imaging materials include chromium, nickel,
titanium, cobalt, gold, platinum, rhodium, iridium,
Metals such as ruthenium, tantalum, niobium, tungsten, molybdenum, heat-resistant alloys; semi-metals such as carbon, silicon; Rub, Cr, 03, SCs Tic % 5
isL, WCs, TaCs, TaN, 1T+N, and other ceramics (those with a large optical contrast with the substrate, similar to the specific example of the substrate 14 described later).

Specific examples of the substrate 14 include metals with high heat resistance, corrosion resistance, and mechanical durability, ceramics (including heat-resistant glass), laminates or sandwich structures of metals and ceramics, and the like.

Specific examples of metals include simple metals such as nickel, conorct, chromium, titanium, and platinum, niobium-based alloys, molybdenum-based alloys, tantalum-based alloys, tungsten-based alloys, chromium-based alloys, nickel-based alloys, and cobalt-based alloys. , other super heat-resistant alloys, and others.

Specific examples of ceramics include alumina, mullite,
Steatite, silica, beryllia, zirconia, titania, chromium carbide, silicon carbide, aluminum nitride, silicon nitride, titanium nitride: silicate glass (e.g. Vycor glass manufactured by Corning), borosilicate glass (e.g. Pyrex glass manufactured by Corning), crystal Examples include chemical glass and others.

Furthermore, a structure in which the surface of ceramic is coated with a different type of ceramic or metal can also be used.

Among these, those with a maximum operating temperature in air of about 1000°C or higher, preferably about 1200°C or higher, more preferably about 1
Temperatures of 500°C or higher are suitable for the present invention.

The thickness of the substrate 14 is suitably between about 0.2 mm and about 100 mm, but is not limited to this range.

As an example of a preferred combination of the substrate 14 and the image forming material, the substrate preferably has a white color or metallic luster for reflective images, is transparent for transmitting images, and the image forming material is preferably close to black. desirable.

Particularly desirable examples of the substrate include super heat-resistant alloys such as chromium-based, nickel-based, cobalt-based, niobium-based, molybdenum-based, tantalum-based, and tungsten-based, and ceramics such as alumina, mullite, steatite, zirconia, silica, and titania. , heat-resistant glass.

Particularly desirable examples of imaging materials include chromium,
Metals such as cobalt, titanium, molybdenum, tungsten, silicon, gold, platinum, rhodium, iridium, ruthenium, Ru5t, Cr, Os, 5iC1TiC, 51
Examples include ceramics such as sNr and WC.

In the above description, it has been assumed that the non-dot portion of the halftone image is the surface of the substrate, but a thin layer of another material may be provided between the substrate and the image forming material. The purpose of this is to improve the adhesion between the substrate and the image forming substance, and to improve the optical contrast between the halftone dot areas and the non-dot areas. In this case, the non-dotted portion is the surface of the thin layer.

The first aspect of the present invention has been described above, and the second aspect of the present invention will be described below.

In the first embodiment, one substrate mechanically and thermally
Furthermore, it was about something that was chemically durable.

However, although metals have great mechanical and chemical durability, their heat resistance is considerably lower than that of ceramics. Furthermore, although ceramics have great thermal and chemical durability, their mechanical durability (especially toughness) is inferior to metals. Therefore, if you own two types of durable image boards, one made of metal and the other made of ceramic, that have the same image, even if one deteriorates, there is a very high possibility that the other will remain intact, so you can use both. When a seed is considered as a single image, its durability becomes very large. This is the second aspect of the invention.

For example, if magnesia, calcia, or the like is used as a ceramic substrate, it is relatively weak mechanically and chemically, but has a heat resistance of 2,000 and several hundred degrees Celsius in air. Zirconia also has similar heat resistance and is chemically stable.

Furthermore, among the specific examples of the substrate 14 described above, there are many ceramics that have durability of 1500° C. or higher. Therefore, if you own a pair of durable image boards that use these ceramic substrates and durable image boards that use metal substrates, you have a higher chance of surviving a fire or earthquake disaster than owning one durable image board. It's much bigger than it is.

There may be a set of three or more durable image plates of two types for the same image. For example, a combination of two durable image plates made of different types of ceramic substrates and one durable image plate made of metal substrates may be used.

The durable image boards mentioned above have a much higher specific gravity than water, so if they encounter water damage such as a flood, they may sink to the bottom of the water or be buried in the soil, and may go missing.

A third aspect of the present invention is a durable image plate in which a highly durable image is formed on a highly durable substrate with a low specific gravity, and whose specific gravity as a whole is less than 1.

A highly durable image is provided in the same manner as described above. A durable protective layer is also provided in the same manner as described above.

Examples of substrates with high durability and low specific gravity include highly durable metal or ceramic substrates having minute bubbles or holes inside, and highly durable metal or ceramic airtight hollow bodies. If the microbubbles or pores are water permeable, the surface of the substrate is sealed with a thin layer of highly durable metal or ceramic to make the inside airtight.

The durable image plate of the third embodiment has inferior mechanical durability compared to the durable image plates of the second and second embodiments, but is incomparable compared to conventional photographs, printing plates, printed matter, etc. It has great durability. It can be preserved forever unless subjected to large mechanical destructive forces.

A fourth aspect of the present invention is to combine durable image plates with high heat resistance for the same image so that any durable image plate will survive any disaster such as fire, earthquake, flood, etc. It consists of three types: a durable image board with great mechanical durability and a durable image board that floats on water. It may consist of a set of four or more durable image plates.

Different types of durable image boards (for example, durable image boards made of highly heat-resistant ceramics and durable image boards made of mechanically strong metal) may be stored in separate locations or in the same box. May be stored. Alternatively, two durable image plates, one made of metal and one made of ceramics, may be stacked on top of each other and the four corners secured with screws for storage. If the images are facing each other with the image side facing inside, there is an advantage that the images are less likely to be scratched. In this case, if images are formed on both sides of the substrate, there is no problem that the images become invisible because the images are also formed on the front side.

In addition, the same image is formed on both sides of a metal substrate, and the negative image side is covered with a durable metal plate, and the same image as above is formed on both sides of a ceramic substrate, and one image side is covered with a ceramic plate. It may also be used as a set with a covered item.

Incidentally, in the present invention, the ceramic substrate also includes the above-mentioned heat-resistant glass substrate.

Although the durable image plate of the present invention can be directly applied with the naked eye,
To reproduce it with a reproduction device, there are two methods: scanning each dot with an energy beam such as a laser beam and reading the size of the reflected or transmitted light, and another method using an optical system to read it one-dimensionally or two-dimensionally. There is a method. When using an energy beam, the energy beam is stored in the memory and displayed on the CRT.
, displayed on an LCD monitor or the like, or connected to a printer to create a hard copy. When reading out optically, a hard copy is created by viewing with the naked eye, projecting onto a screen, looking into an aerial image, or focusing on a photosensitive material.

When optically displaying on a screen or exposing a photosensitive material to make a hard copy, it is desirable that the durable image plate be of a transmissive type and that the dots forming the halftone image be opaque.

The halftone image according to the invention is advantageously recorded as a monochromatic image. The reason for this is that there is no material that can express the three primary colors using only materials that have high heat resistance, corrosion resistance, mechanical durability, etc. Although it is not a natural color, a multicolor image may be created by combining a plurality of monochrome images.

Next, a specific example of a durable image board and a method for producing the same will be described based on an example.

<Example 1> A halftone negative film having a size of 4×5 inches and a screen line count of 200 lines/inch was produced from a cabinet-sized black and white portrait photograph using a monochrome scanner.

Using the obtained halftone dot negative film as a photomask, the following photolithography process was carried out.

Approximately 2 mI+ thick as a durable image board substrate, size 4×
One side of a 5-inch super heat-resistant alloy (Hastelloy C) was finished with a mirror gloss finish, and then hard chrome plating was applied to a thickness of 20 μm, and a photoresist (0FPR-800 manufactured by Tokyo Ohka Co., Ltd.) was applied on top of that. Dry the coating to a thickness of 1,5
After prebaking at about 85° C. for 30 minutes, the photomask was placed on the photoresist film so that the image surface was in contact with the photoresist film, and the entire surface was irradiated with ultraviolet light through the photomask. Next, the photoresist film was developed using a photoresist developer (manufactured by Tokyo Ohka Co., Ltd., trade name: NMD-3), and the photoresist in the portions irradiated with ultraviolet rays was removed. The photoresist pattern thus obtained was heated in a hot air circulation heating machine at approximately 130°C for 20 minutes.
After boost baking for a minute to improve durability against subsequent etching, etching was performed using an etching solution (chromium etching solution H-Y manufactured by Wako Pure Chemical Industries, Ltd.). The chromium layer in the area where the photoresist was removed was etched to a depth of about 0.5 μm. The etched areas were slightly light-scattering and the image could be seen with the naked eye, but it was far from a beautiful photograph.

Next, by sputtering, approximately 0.0 mm of silicon carbide is applied to the entire surface.
The thickness was 5 μm. Then photoresist removal solution (
After removing the photoresist with Stripper Liquid-105 (manufactured by Tokyo Ohka Co., Ltd.), washing with isopropyl alcohol, rinsing with water, and drying, a beautiful jet black image was obtained on a background with a metallic luster of chrome.

When the thus obtained durable image plate was exposed to 1200° C. in the atmosphere for several hours, the background was colored pale brown, but it was sufficiently beautiful.

When the above-mentioned durable picture plate was coated with a transparent protective layer of silica to a thickness of about 5 μm on its surface before being heated in the air, almost no coloring occurred even when heated under the above-mentioned conditions for a long time.

Two of the above-mentioned durable image plates having the same image were produced, stacked one on top of the other so that the image surface of one faced the back of the other, and the four corners were secured with screws. This structure has the advantage that even if the image exposed on the surface is damaged for some reason, an intact image is preserved on the inside.

A similar effect was obtained by forming the same image on both sides of the substrate and covering one side with a durable plate.

The protection techniques described above can also be applied to other examples.

<Example 2> Transparent silica (artificial quartz crystal) having a specular luster and having a thickness of approximately 3 Ωm and a size of 4 × 5 inches was used as a substrate for a durable image plate, and chromium was applied on it by sputtering to a thickness of approximately 0.3 μm.
The thickness was set at . On this mirror-like chrome surface,
A photoresist coating film was prepared in the same manner as in Example 1, followed by pre-bake, contact image exposure through a photomask (positive separation film with the same image as in Example 1), photoresist development, post-bake, and chrome etching (as in Example 1). A durable image plate was obtained by performing a series of treatments such as using an etching solution) and removing the photoresist. Next, a protective layer of transparent silica is applied by sputtering on the entire surface of the image side.
The thickness was approximately 10 μm.

The thus obtained durable image plate also had extremely high heat resistance, corrosion resistance, and mechanical durability, and the image was safely preserved even when exposed to 1200° C. in the atmosphere for a long time.

Example 3 A high purity white alumina substrate having a light scattering surface and having a thickness of about 5 mm and a size of 8×10 inches was used as the substrate.

Copper was deposited on this substrate by sputtering to a thickness of about 1 μm. Next, a photoresist coating film was applied thereon in the same manner as in Example 1, prebaked, and a photomask (a halftone negative film of size 8 x 10 inches with a line count of 200 lines/inch from the same original as in Example 1). Contact exposure, photoresist development, and post-bake were performed through the wafer.

Next, the copper was etched with a mixed aqueous solution of ferric chloride and hydrochloric acid. Then remove the remaining photoresist with a stripping solution (
It was removed with a stripping solution (104 manufactured by Tokyo Ohka Co., Ltd.) to form a copper pattern. Next, silicon carbide was formed on the entire surface of the pattern to a thickness of about 06 μm by sputtering.

Next, the substrate was immersed in a mixed aqueous solution of ferric chloride and sodium hydroxide, and ultrasonic energy was applied. The copper was dissolved and the silicon carbide above fell off, resulting in a silicon carbide pattern. Ta.

The thus obtained durable image plate was a reflective type durable image plate that was extremely durable and could withstand an atmosphere of 1600°C.

Approximately 1 layer of transparent alumina is sputtered as a protective layer.
The mechanical durability of the -layer was improved when the layer was formed with a thickness of .mu.m.

<Example 4> This example is an example of obtaining a collar durable side a plate.

A color slide with a size of 4 x 5 inches was used as an original, and it was separated into magenta, cyan, yellow, and black dot separation positive film (screen line count: 200 lines/inch, screen size: approximately 100 x 75 mm) using a color scanner. . Using this resolved positive film as a manuscript, it was closely exposed to a high-resolution dry plate, Kodak HRP plate manufactured by Eastman Kodak Company, to obtain a resolved negative plate. Next, using this resolved negative plate as an original, it was exposed on a 4-inch HRP plate by a reduction exposure device to one-fifth (25th in area), and developed and fixed to obtain a resolved positive plate. Using this decomposed positive plate, a photolithography process was performed as described below.

The thickness of the board is approximately 2 mm, and the size is approximately 70 x 60 mm.
Transparent alumina with a mirror-like luster was used. Chromium oxide was provided on this substrate by sputtering to a thickness of about 0.3 μm. Next, a photoresist coating was placed on the chromium oxide film and prebaked in the same manner as in Example 1. Next, using one sheet of the decomposed positive plate as a document, the photoresist film was closely exposed to ultraviolet light. Similarly, three other separated positive plates were sequentially exposed so that four images were arranged in two rows and two columns with an interval of 10 mm on the photoresist film. Next, the photoresist was developed and a post bake was performed. Next, the chromium oxide was etched using the chromium etching solution of Example 1. Next, the remaining photoresist was removed to obtain a transmission-type durable image plate, but in order to further improve heat resistance and mechanical durability, transparent alumina was sputtered on the image side of this durable image plate. A protective layer of about 1 μm thick was provided. The durable image plate obtained in this way is
It was extremely durable and could withstand an atmosphere of 800°C.

When single crystal alumina is used as the substrate, 1
It withstood temperatures of 900°C.

In this embodiment, a color image is made into a durable image plate.

To reproduce such a durable image plate into a color image, one can either illuminate the three images with their corresponding primary color lights (red, green, and blue) and project each image one on top of the other on the same screen, or It is also possible to look into something that is gathered on the same optical axis. Alternatively, a hard copy may be created by reading the three images with a scanner and inputting the image signals to a silver salt color printer, a thermal printer, an inkjet printer, or the like. Alternatively, a halftone separation film may be reproduced and a hard copy may be produced from it using a color proof production method.

<Example 5> A transparent alumina substrate having a thickness of 3 mm and a size of 4×5 inches with specular gloss on both sides was used, and chromium was provided thereon to a thickness of about 0.2 μm. As a photomask, 29
Nine frames of black and white halftone dot images of x2Dmm were used. The photomask was prepared in the same manner as in Example 2, and first a halftone positive film with a screen size of 116 x 80 nm (
200 lines/inch), then closely printed on a 4 x 5 inch HRP plate, and further reduced to 1/4 on an HRP plate of the same size. This process was performed for 9 types of images, and 9 images were applied to one HRP plate.
The halftone images of the pieces are arranged in 3 rows and 3 columns, with an interval of 5 mm between adjacent images.
It was set up so that The same photolithography process as in Example 2 was performed using this photomask.

That is, image exposure of the photoresist film provided on the chrome film, development of the photoresist, etching of the chrome, and removal of the photoresist were carried out to form a durable image plate consisting of 9 frames of monochrome images. Transparent silica was provided as a protective layer to a thickness of about 2 μm by sputtering.

Images include - human childhood, boyhood, adolescence,
We used representative photographs of people in their prime and old age. There are three photos taken during adolescence: a commemorative photo when you become an adult, a commemorative photo when you get married, and a commemorative photo when you give birth. Photos taken when you are in your prime include a commemorative photo when your child entered school and a commemorative photo when your child got married. There are three photos, one from when I retired, and one from each of the others.

If the photos used are in color, you may prepare as many durable image plates as the number of color separations (3 to 4) as shown above, or - durable image plates with color-separated monochrome images recorded on each sheet. may be made.

<Example 6> Heart-shaped pellets made of alumina powder (image surface is flat,
The back surface was molded with a curved surface, and the image forming surface was mirror polished. Next, in the same manner as in Example 2, a halftone dot face photograph (175 lines/inch) of chromium with a protective layer of transparent silica was formed. The name was also etched at the same time. A reduced photomask was used so that the screen size was approximately +2 x 8 mm. A locket (pendant) was created by combining two such pellets together, sealing the seam with platinum, and adding a ring for a chain. If you have something like this in your possession, you can easily identify your identity even if you are burnt to death or your skeletal remains are found in a shipwreck.

<Example 7> A set of three durable image plates each of Examples 1, 2, and 3 was prepared. However, each durable image board was the same size (4 x 5 inches) and had the same image, and the thickness of the durable image boards were 2 mm, 3 mm, and 3 mm, respectively.

The image surface of each durable image plate was covered with a 2 mm thick transparent quartz plate (screwed at the four corners). The durability of such a three-piece set of durable image plates is further improved.

<Example 8> Two durable metal image plates of Example 1 having the same image were manufactured. On the other hand, holes are formed in the four corners of the durable image board.
Screw holes were formed in the four corners of the other durable image board. Next, they were stacked so that the image side of one faced the back side of the other, and the four corners were secured with screws.

This two-ply durable image board is safe because even if the image exposed on the front is damaged for some reason, the image on the inside remains intact.

Two durable image plates made of alumina substrate of Example 7 having the same image were manufactured. In the same manner as above, these two durable image plates were stacked and the four corners were secured with screws.

Even if one image is damaged for some reason in this two-ply durable image board, the other image will remain intact.

<Example 9> 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 ceramic durable image plate of Example 3 was placed on top of this. (However, the size was 4 x 5 inches, and the thickness of the substrate was reduced to about 1 mm) were bonded using cement.

Although the durable image plates thus obtained are inferior in heat resistance and mechanical durability to those of Examples 1 to 5, they float on water and therefore do not submerge even in floods.

<Example 10> In addition to the two types of durable image plates of Example 8, the durable image plate of Example 9 was added to produce a set of three durable image plates.

With the three-piece set obtained in this way, there is a very high probability that one of them will remain no matter what kind of disaster you encounter.

<Example 11> In addition to the three durable image plates of Example 1O, the following durable image plates having a specific gravity of less than 1 were added to prepare four sets of durable image plates.

The substrate is a mirror-polished titanium plate with a thickness of approximately 1 mm and a size of 4 x 5 inches, with this as the top surface and the other surfaces as
A hollow box with a 0.5 mm titanium plate welded to it (the top surface is 4 x 5
inch, height +omm). The thickness inside the box
0.5 mm titanium plates were welded along both diagonals for reinforcement. The inside was made airtight by welding around it so there were no gaps. Therefore, water does not get into the box.

On the upper surface of this hollow box, a durable image of silicon carbide was formed on the titanium surface by the lift-off method in the same manner as in the production of the durable image plate using the ceramic substrate of Example I.

The durable image plate thus obtained had relatively high heat resistance and mechanical durability, and floated on water.

<Example +2> This was the same as Example 7 except that a magnesia substrate was used instead of the silicon dioxide substrate of the durable image plate made of a ceramic substrate. With this combination, there was something that could survive in the atmosphere at temperatures as high as 2,200 degrees Celsius.

<Example 13> A high-purity white alumina substrate having a light scattering surface and having a thickness of about 2 mm and a size of 4×5 inches was used as the substrate. On this substrate, apply a coating film of the following photoresist to a dry film thickness of 1
After contact exposure through a photomask (the same dot negative film as in Example 1), the film was developed with the following developer for about 1 minute, rinsed with the following rinsing solution, and dried. Then, the mixture was betatized in air at about 600° C. for 30 minutes, and then at about 1000° C. for 20 minutes.

The resulting durable image plate withstood 1500°C.

Photoresist Ni Tokyo Ohka Co., Ltd., product name OMR-8
3, a developer in which SiC powder (average particle size: 0.03 μm) was dispersed ultrasonically so that the weight ratio of the dry film photoresist to the SiC powder was about 1:85: manufactured by Tokyo Ohka Co., Ltd. Product Name: OUR Developer Rinser 2 Manufactured by Tokyo Ohka Co., Ltd., Product Name: 0! , lRIJ liquid <Effects of the invention> The durable image plate (Duragraph) according to the present invention has extremely high durability and is incomparably more stable against heat, light, chemicals, moisture, mechanical shock, etc. It is a thing,
It can be said to be a truly durable image board.

You can leave it behind forever as proof that you existed in this world.

Under normal circumstances, it will survive for thousands or tens of thousands of years. Even in the event of a natural disaster, there is an extremely high chance that it will survive.

If you carry it with you at all times as an identification card, pendant, etc., it will be the best way to identify yourself in the event of a disaster.

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. Moreover, it can be viewed as a beautiful monochrome image even with the naked eye.

Furthermore, if a color image is separated into multiple colors, formed on a single durable substrate, and stored as a durable image board, it is convenient for storage and there is no risk of parts being lost. The effect is extremely large because it can reproduce color images and color prints.

[Brief Description of the Drawings] Fig. 1 is a top view of a specific example of the durable image plate according to the present invention, Fig. 2 is a sectional view taken along line A-A of the above-mentioned specific example, and Fig. 3 is an enlarged view of the halftone image area lit. 4 to 7 show specific examples of the manufacturing method of the durable image plate of the present invention. FIG. 4 is a sectional view of a substrate provided with a photoresist film on the surface, and FIG. A side view showing how the mask photosensitive material is irradiated with the energy beam, Figure 6 is a side view showing how the photomask is exposed in close contact with the photoresist film, and Figure 7 is the substrate after the photoresist has been developed. FIG. FIG. 8 is a sectional view of another specific example of the durable image plate, FIG. 9 is a sectional view of an intermediate for obtaining the durable image plate of FIG.
FIG. 0 is a sectional view of a specific example of the durable image plate of the present invention having a protective film. In the figure, lO... Durable image board 14
... Color separation halftone image 12-1112-2.12 of substrate 11, 12.13... Halftone image 11-1.112.11-3...11 -3・・・・・・
12 color separation halftone images 13-1.13-2.13-3・
...13 color separation halftone image 30--Image area 33...Non-image area 31, 32.8
1.82... Enlarged cross section of halftone dot 40...
Photoresist film 41...Thin film (image material) 50...Photomask photosensitive material 60...-
・Photomask 61...Ultraviolet light 62...
...Mask image layer 71...Residual resist 92...Recessed portion 100 provided in the substrate -
...Protective film Figure 8 Hand □ M',:iE''F, (,!If♀February 28□Sent date: Month, Day, 1991

Claims (8)

[Claims] (1) Photolithographic method using an image-forming substance that has high heat resistance, corrosion resistance, and mechanical durability and is different from the substrate on a substrate made of a material that has high heat resistance, corrosion resistance, and mechanical durability. It is confirmed that a visible image with gradation is recorded as a halftone image using a gradation system, and that the optical contrast between the halftone dot area and the non-dot area (substrate surface) is as large as that of a normal printed matter. Features a durable image board. (2) A durable image plate according to claim (1), characterized in that the substrate is selected from Group A below, and the image forming material is selected from Group B below. Group A: Chromium-based, nickel-based, cobalt-based, niobium-based, molybdenum-based, tantalum-based and tungsten-based superalloys; alumina, mullite, steatite, zirconia, silica, titania; silicate glass, borosilicate glass and crystallization Glass group B: chromium, cobalt, titanium, molybdenum, tungsten, silicon, gold, platinum,
Rhodium, iridium, ruthenium; RuO_2, Cr
_2O_3, Si_3N_4, SiC, TiC, WC (3) The same visible image with gradation is produced on a metal substrate with high mechanical durability and a durable ceramic substrate with high heat resistance, which is different from the substrates with high heat resistance, corrosion resistance, and mechanical durability. A different image-forming substance recorded as a halftone image by photolithography, and characterized by the optical contrast between halftone dots and non-dots (substrate surface) being as large as that of ordinary printed matter. Durable image board. (4) A visible image with gradation is formed on a durable metal or ceramic substrate with minute bubbles or pores inside and/or a highly durable hollow metal or ceramic substrate. It is an image-forming substance that is highly corrosive and mechanically durable and is different from the substrate, and is recorded as a halftone image by photolithography, and the difference between halftone dots and non-dots (substrate surface) is A durable image plate characterized by having optical contrast as high as that of ordinary printed matter and having an overall specific gravity of less than 1. (5) A durable image plate having the same visible image and comprising at least three types of durable image plates comprising at least two types of durable image plates according to claim (3) having the same visible image and at least one type of durable image plate according to claim (4). (6) Claims (1), (2), (3), (4) and (5)
), the visible image with gradation is a color image,
A durable image board characterized in that the halftone dot image consists of a plurality of color-separated halftone dot images separated into a plurality of colors. (7) Claims (1), (2), (3), (4), (5)
and (6), a durable image plate characterized in that a transparent protective layer having high heat resistance, corrosion resistance, and mechanical durability is provided on the halftone image. (8) Claims (1), (2), (3), (4), (5)
, (6) and (7), the optical density difference for white light between the halftone dot area and the non-dot area is 0 in the case of a reflective image.
．． A durable image board characterized by having a rating of 9 or more, and 1.4 or more in the case of a transparent image.