JPH0692191B2 - Method for manufacturing optical recording thin film medium - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing an optical recording thin film medium for performing recording by irradiation of recording light without using a direct heating means such as a thermal recording head.

[Technical background of the invention and its problems] The thermal recording method is a direct recording method that does not require development and fixing, and is the mainstream recording method for simple terminals such as printers and facsimiles, making good use of operability and maintainability. Occupy However, since a heating element such as a heating head or a heating pen is in direct contact with the heating element, a sticking phenomenon may occur and the resolution may be degraded.

In order to solve such a defect, Xe-
A method has been proposed in which color is developed by a light source such as a flash and used for recording.

For example, as shown in FIG. 1, an original drawing, for example, a recording transfer original 13 is overlaid on a lower portion of a recording material on which a substrate 11 and a color-developing agent 12 are laminated and exposed by light from a light source 16 to expose a coloring portion 15 of the thermosensitive recording material. A method of developing a heat-sensitive color is conceivable. However, in this recording method, the heat generated in the light absorbing portion 14 of the original drawing is largely diffused, causing blurring and blurring around the recorded image, resulting in a reduction in resolution.

Instead of overlaying the original drawings as described above, in the thermosensitive coloring material,
There are also attempts to record by dispersing a dye that absorbs the wavelength of the exposing light and converting the absorbed light into heat. However, the dye used for this purpose is a visible light absorbing dye such as methylene blue and rhodamine B, and there is a problem that the absorber itself is colored and the contrast after recording is poor. In addition, recently, an optical recording material in which a near-infrared absorbing dye is dispersed in microcapsules and applied is being studied, but as in the case described above, there remains a problem in the uniformity of the color-developed portion due to the nonuniformity of the dispersion. It was For example, in a material system in which a light absorbing agent is added to a dispersion type thermal recording paper, a resolution of about 20 lines / mm is the highest value.

Moreover, in the conventional material system in which the disperse colloid and the microcapsules are non-uniformly dispersed in the binder, the light energy of the recording light source is in the thickness direction of the coloring agent because the recording part becomes opaque (white). There was a large loss of intensity due to scattering, etc., which was also disadvantageous in terms of sensitivity.

Therefore, as a structure of such an optical recording medium, a color former,
It is most suitable that the light absorber and the color developer are uniform in the recording surface direction and dispersed in the thickness direction. Based on such a concept, an optical recording medium was devised in which a thermosensitive color developing agent and a light absorbing agent were uniformly dissolved in a polymer and laminated by spin coating. However, in this medium, the concentration of the color former in the thin film layer is lowered because the polymer is dissolved as a binder. For this reason, in the case of a leuco dye in which a color former and a developer react, it is unavoidable that the reaction rate, that is, the sensitivity, decreases.

When the concentration of the color former is increased, the colorant is not uniformly dissolved in the polymer matrix, and the colorant is microcrystallized in the laminated thin film to cause the thin film to become cloudy, exhibiting a defect similar to the above-mentioned dispersion system.

A more serious problem is the dissolution of the already-coated thin film in the spin-coating solvent, which does not affect the already-coated thin film, and it was very difficult to superimpose several spin-coated thin films.

As described above, in the non-contact type photothermographic recording medium, it has been long awaited that a thin film that maintains a high concentration of the color former be formed and laminated by a process that does not use a solvent such as vacuum deposition.

[Object of the Invention]

In order to solve the drawbacks of the optical recording medium as described above, the present invention provides high sensitivity and high contrast by stacking and multiplexing a thin film material capable of recording by vacuum evaporation by irradiation with near infrared light or the like. It is an object of the present invention to provide a method for manufacturing an optical recording thin film medium.

Example of Invention

The basic structure of the optical recording thin film medium according to the present invention is shown in FIG. In FIG. 2, 21 is a substrate, 22 is a color former layer, 23 is a light absorber layer, 24 is a color former layer, and 25 is the direction of recording illumination light. An optical recording thin film medium capable of multiple color development can be manufactured by laminating at least one set of this basic structure by the present manufacturing method.

To realize the structure shown in FIG. 2, two components of the thermosensitive coloring material and a light absorber are vapor-deposited on the substrate 21. Therefore, each layer in FIG. 2 is close to a bulk, and solids having a considerably high color former concentration are laminated.

The advantage of this method is that (1) a vacuum evaporation method is used, which is a manufacturing method with which uniformity and film thickness can be easily controlled. (2) Since the stacking is performed only by switching the vapor deposition source, the influence of the stacking of the upper layer on the lower layer is smaller than that of a method such as spin coating.
(3) The effective concentration of the material in each layer is high, and the color developing sensitivity, speed, and contrast are improved as compared with the method of spin coating the binder and the color developing agent or the dye dissolved in the solvent. As the substrate, a light transmitting material such as a plastic sheet, a plastic plate (acrylic, polycarbonate), a glass plate or the like can be used. When used as a reflected light readout type, an opaque material such as a high quality paper or a metal plate (aluminum or the like) of a high thermal conductivity material can be used as the substrate.

A combination of some leuco dyes called NCR type and a color developer is used as the heat-sensitive color former. Specific leuco dyes include crystal violet lactone (purple blue),
Benzoyl leuco methylene blue (blue), RED-DCF
(Red, Hodogaya Chemical Co., Ltd.), TH-107 (black, Hodogaya Chemical Co., Ltd.), Malachite Troico Green (green), 3-chloro-6
Microhexyl aminofluoran (yellow orange) React Yellow (manufactured by BASF Japan) is raised. As the developer, bisphenol A (bisphenol Z), 4-hydroxyphenoxide or the like can be used.

As the light absorber, a dye that can be vapor-deposited can be used so as not to overlap the absorption region of the color former. Specific examples are phthalocyanine blue, fluorescein, rhodamine.
A visible light region dye capable of vacuum deposition such as 6GC.I.Disperse Yellow 5 (Sumikaron Yellow 5GE Sumitomo Chemical Co., Ltd.) can be used. Further, when a near-infrared light absorbing agent is used, since it does not overlap the absorption of visible light, it is possible to form multiple colors relatively easily. As the near-infrared absorbing dye having absorption in this region, squarylium dyes such as diethylaminonaphthol squarylium and dimethylaminonaphthol squarylium, and NKX-113 (manufactured by Japan Photosensitive Dye Co., Ltd.) can be used. Further, metal complex salts of bis- [miss 1,2 tolujha] ethylene-1,2 dithiolate nickel, bis- (1 chloro 3,4 dithiophenolate) nickel and the like can also be used. As a specific example, as the above-mentioned metal complex salt, a near infrared absorber PA-1001 (1100 nm) manufactured by Mitsui Toatsu Fine Co., Ltd.,
PA-1002 (895nm), PA-1003 (850nm), PA-1005 (850n
m), PA-1006 (870 nm), and those obtained by treating and removing stable salts from these absorbents can be used. ()
The numbers inside indicate the absorption wavelength.

These near-infrared absorbers have an absorption coefficient of only about 1/100 of the maximum absorption wavelength region (near-infrared region) in the visible region (400-700 nm), while keeping the visible region substantially transparent. It can absorb light in the near infrared region.

Next, a method for manufacturing the optical recording thin film medium of the present invention will be described.

The above coloring material is vacuum-deposited on the substrate. Next, the light absorber layer is vacuum deposited and laminated, and then the color former is further vacuum deposited and laminated. By this method, a transparent homogeneous vapor-deposited film can be formed, but depending on the nature of the color former, even if vacuum vapor-deposition such as bisphenol A is performed, fine crystals are deposited,
It may be difficult to obtain a transparent thin film. This phenomenon is remarkable in the color developer among the above-mentioned two components of the color developer. We found the following method to prevent this. A raw material for vapor deposition is prepared by dispersing and mixing an appropriate amount of an aromatic amide and an aliphatic amide in a color developer that easily causes such crystallization. When this material is vacuum-deposited from the vapor deposition boat, a solid solution thin film of aliphatic amide and developer amide is generated, and a thin film with excellent transparency and surface uniformity is prepared compared to the vapor deposition film of the developer alone. You can FIG. 3 shows a comparison between the light transmittance of the developer layer obtained by the above method and the transmittance of each developer unit. That is, 31 represents the transmittance of the vapor deposited film of the developer alone, and 32 represents the transmittance of the vapor deposited film of the amide / developer mixture. In the case of multiple color development, a laminated film can be similarly produced by repeating the above operation.

Examples of the present invention will be described below.

(Example 1) The following raw materials were placed in a Ta boat, respectively, heated in a vacuum chamber of 1 x 10 ^-5 Torr or less, vapor-deposited on a glass substrate, and each thin film was laminated.

The absorption characteristics of the optical recording thin film thus obtained are shown in FIG. 41
Indicates the transmittance of the thin film before light irradiation, and 42 indicates the transmittance of the thin film after light irradiation. The absorption around 450 nm is based on the absorption of fluorescein. When this thin film was irradiated with Ar laser light (10 mW) having a wavelength of 488 nm at a spot of 10 μmφ and irradiated for 100 nsec, it was colored blue as shown by the broken line in FIG. When the mask of the metal pattern was brought into close contact and the laser beam was spread and irradiated, a line and space of 5 μm could be resolved.

(Example 2) Similar to Example 1, the following raw materials were sequentially vacuum-deposited from an Ta boat on an acrylic plate to form thin films. A Mylar film was pressure-bonded and laminated on this thin film to form a recording thin film.

A wavelength of 830 nm was applied to the optical recording thin film thus obtained from the acrylic plate side.
Was irradiated with the semiconductor laser light. Laser light output 6mW, 1.6μ
It was colored red by pulsed light of 30 nsec under the condition of mφ spot diameter. The recording sensitivity was about 20 mJ / cm ² .

(Example 3) The following raw materials were vacuum-deposited on a Mylar film from a Mo vapor deposition boat to perform lamination to prepare an optical recording thin film. Fifth
The structure of this recording thin film is shown in the figure. In FIG.
51 is a substrate, 52 is a color former layer (I), 53 is a light absorber layer (I), 54 is a developer layer, 55 is a light absorber layer (II), and 56 is a color former layer (II). .

When this recording thin film was exposed to a semiconductor laser having a wavelength of 850 nm, blue color was generated, and when exposed to a wavelength of 1100 nm, red color was generated. By using this thin film, multiple color recording of two colors could be performed. The recording sensitivity was about 20 mJ / cm ² .

〔The invention's effect〕

As described above, by using the present invention, it is possible to manufacture a medium for performing high-contrast recording with high resolution by irradiation with light such as a semiconductor laser without using a direct heating method such as a thermal head. In addition, in the produced optical recording thin film medium, since the color former layer is a transparent thin film and is uniform and the color former concentration is much higher than that of the binder dispersion system, even when the color formers are laminated in multiple layers, It has the advantages of low light loss and high color development sensitivity. Further, in terms of resolution, there is an advantage that it is extremely improved as compared with a binder dispersion type microcapsule dispersion type thermosensitive color developing agent. In addition, it is an organic thin film with low thermal conductivity,
Since the light absorber is thermally isolated from the substrate, the light energy of the irradiation light is intensively absorbed by the thin film, resulting in extremely high sensitivity. When using the reflected light readout type, a metal is used as the substrate. Therefore, it has an advantage that a high thermal conductivity material can be used. Therefore, the method for producing an optical recording thin film medium according to the present invention makes it possible to realize high-contrast, high-speed multicolor recording, and is a recording material suitable for application to a wavelength multiplexing optical disc medium and a color microfilm. Further, in the structure of sandwiching a transparent body as in (Example 2), solvent resistance and moisture resistance can be remarkably improved as compared with the conventional color former.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing a conventional photothermographic recording medium, and FIG.
FIG. 3 is a cross-sectional view showing an example of the basic constitution of an optical recording thin film medium according to the present invention, FIG. 3 is a view showing an example of light transmittance characteristics of a color developer layer according to the present invention, and FIG. FIG. 5 is a diagram showing an example of the characteristics of such an optical recording thin film medium, and FIG. 5 is a sectional view showing an example of the configuration of the multiple color recording thin film according to the present invention. 11 …… Substrate, 12 …… Coloring agent, 13 …… Record transfer original, 14
...... Original light absorption part, 15 ...... Coloring part, 16 ...... Light source, 21 ...
… Substrate, 22 …… Coloring agent layer, 23 …… Light absorbing agent layer, 24 …… Coloring agent layer, 25 …… Direction of recording irradiation light, 31 …… Transmittance of developer developer vapor deposition film, 32 …… … Transmittance of vapor deposition film of amide / developer mixture, 41 …… Transmittance of thin film before light irradiation (solid line), 42
…… Transmittance of thin film after light irradiation (broken line), 51 …… Substrate, 52
…… Color former layer (I), 53 …… Light absorber layer (I), 54 ……
Developer layer 55, light absorber layer (II), 56 color former layer (II).

Claims (1)

[Claims] 1. A leuco dye layer is laminated on a substrate by vacuum vapor deposition, and then a light absorber layer comprising a visible light region absorber or a near infrared light region absorber is vacuum deposited on the leuco dye layer. And then laminated using a vacuum deposition a developer layer in which an aromatic or aliphatic amide is dispersed and mixed on the light absorber layer, by combining the leuco dye layer and the developer layer. A method for producing an optical recording thin film medium, which comprises forming a thermosensitive color former layer.