JPS6140980B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an image-forming material having excellent image-forming ability and improved stability. Some image-forming materials with a metal layer provided on a substrate are already known, but image-forming methods that utilize so-called metal layer dispersion have traditionally had poor image-forming ability and stability. Neither of them were found to be good. Dispersion of the metal layer described above means melting the metal layer by applying light or heat and using surface tension to transform it into an aggregate of relatively discontinuous small particles. . As an image forming material that utilizes such a change in the shape of a metal layer, for example, one using bismuth as a metal layer is known, as described in Japanese Patent Application Laid-Open No. 51-59626. There is. However, according to the results of studies conducted by the present inventors, bismuth deposited on a polyester film does not exhibit gradation, has low resolution, and is easily oxidized, resulting in a decrease in optical density over time and a decrease in sensitivity. and the change in resolution was large. In view of this situation, as a result of intensive studies aimed at improving the above-mentioned properties, the following results were obtained and the present invention was completed. (1) In order to improve image forming performance such as gradation and resolution, a bismuth layer is provided on the lead layer as the main metal layer, and the weight ratio of the main metal layer and bismuth is
Preferably from 30:70 to 70:30. (2) By providing layers of germanium or germanium oxide above and below the main metal layer,
Stability is improved and imageability is further improved. The main metal layer can be formed by vapor deposition, sputtering, ion plating, or other thin film formation techniques, but depending on the conditions, alloying of lead and bismuth may occur when layering lead and then bismuth. be. There is nothing wrong with this. Germanium or germanium oxide is provided on such a main metal layer, and it is called a stabilizing layer because it has a remarkable effect of improving stability. However, not only the stability is improved, but also the image forming ability is improved. It is most preferable to provide germanium or germanium oxide as the above-mentioned stabilizing layer above and below the main metal layer, and the improvement effect is relatively small if only the upper layer or the lower layer of the main metal layer is used. By providing stabilizing layers above and below the main metal layer, the decrease in optical density over time is extremely small.
Changes in sensitivity and gradation can be suppressed, and it is also possible to reduce minimum optical density (ODmin) and improve gradation and sensitivity. A layer of germanium or germanium oxide can be formed by vapor deposition, sputtering, ion plating, or the like. However, these
Depending on the conditions, a layer is often formed as a mixture of germanium, germanium dioxide, lower oxides of germanium, and the like. However, this does not impair the effects of the present invention. The substrate used in the present invention includes inorganic materials such as glass and mica, as well as organic materials such as polyester, cellulose acetate, nitrocellulose, polyethylene, polypropylene, polyvinyl chloride,
Examples include, but are not limited to, films and plates made of polyamide, polystyrene, polymethyl methacrylate, and the like. Further, an undercoat layer may be provided on these materials in advance. Among the above substrates, polyester film is preferred. The main metal layer. As mentioned above, it contains lead and bismuth, but their proportions can vary widely. Preferably, the weight ratio of lead and bismuth is 30:70 to 70:
It is 30. If the amount of bismuth increases, gradation and resolution tend to be insufficient, and if the amount of lead increases, sensitivity tends to deteriorate. The main metal layer may include a third component. Such examples include indium,
Aluminum, tin, zinc, antimony, selenium, tellurium, cadmium, thallium, gold, palladium, copper, magnesium, rhodium, germanium, manganese, chromium, etc., as well as lead oxide, bismuth oxide, germanium oxide, tin oxide, silicon oxide From the viewpoint of image forming ability, the amount is 40% by weight or less. The thickness of the main metal layer is determined depending on the application, but is approximately 100 Å to 5000 Å. Regarding germanium or germanium oxide as the stabilizing layer, the film thickness is preferably about 5 Å to 300 Å. For improved stability, the presence of a germanium or germanium oxide layer (referred to as a layer below the main metal layer) is important between the substrate and the main metal layer. However, this lower layer regulates the structure of the main metal layer when it is formed and has an effect on surface tension, so the proper film thickness is set in consideration of image forming ability. In particular, germanium has a thickness of 5 to 50 Å.
is preferable, and for germanium oxide, 10 to 150 Å is preferable. From the point of view of improving stability, it is necessary to provide germanium or germanium oxide on the other side of the main metal layer (referred to as the upper layer).
The upper layer also has a thickness of 5 Å or more so that it does not affect the surface tension and becomes a barrier to the shape change of the main metal layer.
Select a film thickness between 200 Å. The thinner the germanium, the better. In light of the purpose of the present invention, it is preferable to provide a layer mainly composed of an organic polymer as the outermost layer. This layer may be effective in improving dispersion and stability, and may also help protect against mechanical damage. Examples of such organic polymers include polyvinylidene chloride, vinylidene chloride and acrylonitrile copolymer, polyvinyl chloride, polyimide,
Polyvinyl cinnamate, polyisoprene, polybutadiene, polystyrene, polymethyl methacrylate, polyurethane, polyvinyl butyral,
Examples include fluororubber, polyamide, polyester, polyepoxy, silicone resin, cellulose acetate, etc., singly or in mixtures. Among these, polyester and fluororubber are preferred. To these, addition of silicone oil, antistatic agent, crosslinking agent, etc. is preferable from the viewpoint of improving process performance and film strength. Of course, two or more layers mainly composed of organic polymers may be stacked. These can be prepared by dissolving the organic polymer in a suitable solvent and applying it or laminating it as a thin film.
Provide a thickness of μ to 10μ. Preferably it is 2μ or less. The image-forming material of the present invention has the above-described structure, and one method for forming an image is to apply energy sufficient to disperse the main metal layer in a pattern. Specifically, masks having appropriate contrast are overlapped and transferred.
The mask in this case may have images with different light transmittances. As the mask, a chrome mask, dry silver film, diazo film, etc. are used. The energy during transfer is
Pulsed radiant energy is preferred, and flash lamps, particularly xenon flash lamps, are preferred. Further, image formation can also be performed using infrared lamps, laser beams, electron beams, and the like. Instead of irradiating light through a mask, an image can also be formed by irradiating light from the substrate side and bringing a material with a different thermal conductivity into contact with the opposite side of the irradiated surface. Spot formation is also possible with laser light. In this case, some of the main metal layer may evaporate, but before that, a shape change due to the action of surface tension usually occurs, so the improvement of the image forming material of the present invention The properties described are useful. Heat can also be used to form spots. It is also possible to form an image by causing a change in the shape of the main metal layer by means of a so-called heat head. Since a wide range of image forming methods can be applied as described above, the image forming material of the present invention can be used in many fields. Particularly preferred is a roll-shaped or card-shaped microfilm,
In addition, it is useful for video discs, copying films, printing substrates, etc. Examples are given below, and the performance in the examples was determined as follows. Image forming ability was mainly determined using a xenon flash lamp. Sensitivity was determined by the magnitude of the input voltage to the xenon lamp to reach a certain optical density. The gradation is determined by transferring a mask film with the step tablet imprinted on it, measuring the optical density of the mask film and the optical density of the corresponding part of the transferred image area, and using the slope of the straight line part, gamma ( γ).
The resolution was measured by transferring a mask with a resolution target. Stability was determined by changes in optical density, sensitivity, resolution, etc. when left in a constant temperature and humidity environment at 40°C and 90% RH. Example 1 Highly purified germanium was deposited on a 150 μm polyester film (lower layer germanium) to a film thickness of 15 Å. Next, lead was evaporated to a film thickness of 350 Å, and bismuth was evaporated from another boat.
The layers were stacked to a thickness of 300 Å. Finally, germanium is deposited (upper layer germanium) to 15Å
Laminated. The results of evaluating this film are as follows. Sensitivity 850 volts γ 3 Resolution 200 lines/mm Stability (left for 10 days) Optical density reduction rate 5% Sensitivity 870 volts Resolution 180 lines/mm Comparative example 1 In Example 1, in order to investigate the effect of the upper and lower germanium layers, approximately By vapor deposition under the same conditions, the first
Films with the structures shown in the table were made and evaluated.

[Table] Example 2 A germanium dioxide target of 99.99% purity was deposited on a 120μ polyester film.
A germanium oxide layer with a thickness of 50 Å was formed by RF sputtering, and lead and bismuth were removed by vapor deposition from a boat containing lead and a boat containing bismuth, and a layer of lead 600 nm was deposited on the germanium oxide layer.
The thickness of the bismuth film was 500 Å. Then, a germanium oxide layer with a thickness of 30 Å was formed by sputtering. This film has a sensitivity
830V, γ3.0, resolution 200 lines/mm, stability: optical density decrease rate (14 days) 5%, sensitivity
It was 850V and had a resolution of 180 lines/mm. Furthermore, when fluorocarbon rubber (trade name: Technoflon) dissolved in methyl ethyl ketone is applied and dried to a thickness of 0.5μ, γ is 2.5, the optical density decreases by 2%, and the resolution is 200 lines. /
mm was maintained. Example 3 Vapor deposition on 100μ cellulose acetate film,
Therefore, germanium was provided to a thickness of 20 Å. Lead was layered on top of this by vapor deposition, and when a layer of 200 Å was layered, while continuing the lead vapor deposition, the bismuth placed in another boat was started, resulting in a total of 400 Å of lead.
Å, when the bismuth film has a thickness of 200 Å,
The evaporation of lead was stopped and only bismuth was continued to be deposited to form an additional layer of 200 Å. Then, germanium oxide was deposited to a thickness of 40 Å by vapor deposition. A polyester resin (trade name: Vyron) dissolved in ethoxyethyl acetate was applied to this film, and after drying,
The film thickness was set at μ. The film has a sensitivity of 820V, γ2.0, and a resolution of 220.
In the stability evaluation, after leaving it for one month,
The optical density reduction rate was 3%, and there was almost no change in sensitivity or resolution.

Claims (1)

[Claims] 1 Consisting of a substrate, a main metal layer, and a stabilizing layer, the main metal layer has a bismuth layer on a lead layer, and the weight ratio of lead and bismuth in the main metal layer is 30:70 to 70:
30, wherein the stabilizing layer is made of germanium or germanium oxide, and the stabilizing layer is provided above and below the main metal layer in contact with the main metal layer.