GB2090428A - Permanent gray-scale reproductions including half-tone images - Google Patents
Permanent gray-scale reproductions including half-tone images Download PDFInfo
- Publication number
- GB2090428A GB2090428A GB8128652A GB8128652A GB2090428A GB 2090428 A GB2090428 A GB 2090428A GB 8128652 A GB8128652 A GB 8128652A GB 8128652 A GB8128652 A GB 8128652A GB 2090428 A GB2090428 A GB 2090428A
- Authority
- GB
- United Kingdom
- Prior art keywords
- background region
- thin
- permanent
- accordance
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000033458 reproduction Effects 0.000 title abstract description 22
- 239000010409 thin film Substances 0.000 claims abstract description 44
- 239000000463 material Substances 0.000 claims abstract description 27
- 239000011819 refractory material Substances 0.000 claims abstract 2
- 238000000034 method Methods 0.000 claims description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 4
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims description 4
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 3
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 claims description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 claims description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 2
- 239000012212 insulator Substances 0.000 claims description 2
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 229910001936 tantalum oxide Inorganic materials 0.000 claims description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims 1
- 230000000875 corresponding effect Effects 0.000 claims 1
- 229910052732 germanium Inorganic materials 0.000 claims 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims 1
- 230000000877 morphologic effect Effects 0.000 claims 1
- 229910052751 metal Inorganic materials 0.000 abstract description 6
- 239000002184 metal Substances 0.000 abstract description 6
- 239000004065 semiconductor Substances 0.000 abstract description 5
- 230000000694 effects Effects 0.000 abstract description 4
- 150000002739 metals Chemical class 0.000 abstract description 4
- 239000000919 ceramic Substances 0.000 abstract description 3
- 150000004767 nitrides Chemical class 0.000 abstract description 2
- 239000000126 substance Substances 0.000 abstract description 2
- 230000006866 deterioration Effects 0.000 abstract 1
- 239000010408 film Substances 0.000 description 12
- 239000003086 colorant Substances 0.000 description 5
- 230000010363 phase shift Effects 0.000 description 5
- 230000001066 destructive effect Effects 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000003124 biologic agent Substances 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/54—Absorbers, e.g. of opaque materials
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/50—Mask blanks not covered by G03F1/20 - G03F1/34; Preparation thereof
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Solid State Image Pick-Up Elements (AREA)
- Laminated Bodies (AREA)
- Optical Filters (AREA)
Abstract
A refractory background region 1 bears refractory thin-film dichroic filter means 3 patterned to conform to the reproduced half-tone image. Preferred background region materials include metals, semiconductors, and ceramics; the thin-film materials are preferably oxides or nitrides of metals and semiconductors. If the refractory materials are appropriately selected, the reproductions are highly resistant to chemical and thermal deterioration and should have useful lives of the hundreds of thousands of years. The image is produced by interference effects in the thin film. <IMAGE>
Description
SPECIFICATION
Permanent reproductions and formation method therefor
This invention relates generally to permanent grayscale reproductions and more particularly relates to permanent reproductions of half-tone monochrome images.
Reproductions such as photographic prints and ink-based prints degrade significantly upon exposure to light, extremes of temperature, chemical corrosion, and active biological agents. Significant quality degradation may occur in days to decades depending on the nature of the ambient. When such reproductions are used outdoors, they must either be renewed periodically or suitably sealed. Sealing in general deteriorates image quality as the integrity of the seal increases, and does not preclude photochemical and thermal degradation.
The best-known alternative reproduction technique for enhanced lifteime is metal-based intaglio. By stamping or chemical-etching a metallic background material, images of limited quality may be reproduced. Only etching is practical for fine detail.
Neither stamping nor etching is compatible with refractory background materials, so there is a fundamental tradeoff between image quality (eg resolution) and permanence in this technology. In addition, the image is reproduced by textural variations and thus does not have a true gray-scale.
It is a primary object of this invention to provide an improved reproduction which may have both high resolution and longevity in hostile environments.
It is yet another object of this invention to provide a gray-scale reproduction of a half-tone monochrome image using thin films.
It is yet a further object of this invention to provide a permanent gray-scale reproduction of a half-tone image using thin films.
It is yet an additional object of this invention to provide a permanent gray-scale reproduction of a half-tone monochrome image with a choice of colors using thin films.
By "refractory" as used herein is meant inorganic materials selected for their permanence in the intended environment.
In accordance with one embodiment of this invention, there is disclosed a permanent image comprising a background region of a substantially reflective metal, semiconductor, or ceramic, bearing dichroic refractory thin-film means which is patterned to correspond to a predetermined half-tone image. By suitable selection of the index of refraction and thickness of the thin film means, which is preferably a transparent insulator, variation of the monochrome color is possible. The reflective background material, which may also serve as the support means, provides a reproduction viewed in the reflective mode with front lighting.
In accordance with another embodiment of the invention, there is disclosed a permanent image comprising a substantially transparent refractory background material bearing refactory thin-film means patterned to correspond to a predetermined half-tone image. The transparent background material, which may also serve as the support means, allows viewing of the reproduction by back-lighting in the transmissive mode.
In accordance with yet another embodiment of the invention, there is disclosed a permanent image comprising refractory background material bearing thin films means having two different thicknesses corresponding to a predetermined half-tone image.
This embodiment permits modification of the color of the background region.
The foregoing and other features and advantages of the invention will be apparent from the following, more particular, description of the embodiments of the invention, as illustrated in the accompanying drawings.
Figure 1 illustrates the variation in reflectance of a thin-film layer on a substantially reflecting substrate as a function of the indices of refraction for both the film and the substrate.
Figure 2 shows the phase shift through the thin-film versus its thickness with color as a para meterforspecified indices of refraction.
Figure 3 is illustrative of gray-scale obtention by the half-tone technique.
Figures 4A and 4B are sectional views of a preferred embodiment of the invention including a method for forming the image.
In a photograph or an inked reproduction, the visible image results from the contrast between regions where incident light is absorbed in the ink or emulsion, and background regions where incident light is reflected. The reproduction of the present invention is based on contrast produced by interference effects in a transparent thin-film layer located over a reflective or partially reflective background material.Referring to Figure 1,there is shown the reflectance of such a combination for three different indices of refraction of n8 of the background material versus the thin-film index of refraction n. The light reflected from the thin film and the light transmitted through the thin film and reflected from the background region will combine destructively if the phase shift on double passage through the film is an odd multiple of# Jlradians.
Figure 1 illustrates the variation in reflectance in the case of destructive interference, for example where the film is a quarter-wave plate at the wavelength of the observation. At unity abscissa, the reflectance is that of the background region, and increases with its index refraction. As the film index of refraction increases, the reflectance falls to zero when n, = 5, corresponding to a matched thin film. As nr increases above nS, reflection from the thin film increases and there is no phase shift at the film-background interface. In that case there is constructive interference for a quarter-wave film thickness.
As will be described in more detail hereinafter, the observed color will be determined by the relative phase shifts of the incident spectrum. As may be seen from Figure 1, contrast suitable for image reproduction corresponding to portions of the background free of the thin film (n1 = 1) versus portions covered by the thin film (n1 > 1) may be achieved by a high reflectance background region selectively overlaid with a quarter-wave film having a lower index of refraction than the background region and preferably being matched to the background region (corresponding to the reflectance minima in Figure 1).
Referring now to Figure 2, phase shift is shown as a function of film thickness for the system silicon nitride on silicon. Wavelength is a parameter; the primary colors are indicated. Destructive interference occurs for odd multiples of z radians (e itself corresponding to a quarter-wave film) and constructive interference occurs for even multiples of z radians. Figure 2 is thus suggestive of ways to vary color in a monochrome image. For example, if the film thickness is 160 nanometers, the film will be destructive of blue (3yes) and constructive of red (2#), with some loss of green, resulting in a low density yellow. Green and red may be de-emphasized (3z) at about 190 and 230 nanometers respectively to produce yet other colors.
Yet another possibility is suggested by Figure 2.
For this system, there is relatively little dispersion at either or 2x radians. Thus a quarter-wave film will be quite dark, and may be used in conjunction with either the background region alone or with a halfwave film to provide a black and white image.
Referring now to Figure 3, obtention of a greyscale by the half-tone process is illustrated. A pattern of black dots of uniform density on a white background is shown; the area of each square occupied by the black dots increases from left to right. Were
Figure 3 reduced to the point where the individual dots were no longer capable of resolution by the eye, the result would be a triplet of areas appearing light gray, medium gray, and dark gray. By combining such areas with totally white and totally black areas, one obtains a gray-scale limited solely by the resolution with which the black dots may be defined.
For purposes of this application, gray-scale means a range of densities achievable with any two colors and is not limited to black and white.
Preferred embodiments of the invention are now described. Referring to Figures 4A and 4B, a portion of a reproduction and its formation are described.
In Figure 4A, 1 is the background region, which may be of sufficient thickness to provide the primary support means for the reproduction. Suitable mate rialsforthe background region include metals, semiconductors, and ceramics, especially silicon, gallium arsenide, alumina, and sapphire. The background region has a sufficiently smooth surface to admit of the deposition of a uniform thin-film 3 over the area of the desired reproduction. However, the surface should be sufficiently rough to break the mirror effect which degrades the whiteness of the desirably reflective regions and reduces the acceptable span of viewing angles. The background material preferably has a matte finish. Thin-film 3 has a thickness of from one to several quarter-wave lengths in the desired spectrum.Typical thin-films include the oxide and nitrides of metals and semiconductors, preferably silicon monoxide, silicon dioxide, silicon nitride, tantalum oxide, titanium oxide; or alumina. Useful thicknesses for such materials are from 50 to 1000 nanometers. Subject to the necessary thickness uniformity, almost any thin film could be used which has a useful match with the background region in terms of color and contrast.
Atop thin-film 3 is formed a layer 5 of photosensitive material which is exposed to produce a multiplicity of openings 6 corresponding to the desired image including a half-tone image. Etching by any suitable means using the patterned photosensitive layer 5 as a mask results in corresponding openings 60 (see Figure 4B) in the thin-film 3. Where the image is a half-tone image, the area of the openings is proportional to the local intensity of the image.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that modifications thereto are within the scope of the invention. Many such alternatives have already been suggested in the portion of the specification leading up to the description of the preferred embodiments. While particular materials have been described for their known suitability for the permanent reproduction, other materials may be used subject to optical compatibility described hereinbefore and to the further requirement that such materials be refractory in the sense that they resist the contemplated ambient. Thus, other changes in form and detail may be made to the invention without departing from its spirit and scope which is recapitulated in the following summary.
The permanent reproductions of this invention depend on interference and relection effects where a thin-film having a thickness equal to an odd number of quarter-wavelengths of the viewing light overlies predetermined portions of a background region having an index of refraction different from that of the thin-film. As shown in Figure 1 where n1 = 1 corresponding to the absence of the thin film, the background region material is preferably chosen to have either a high reflectance depending on the index of refraction nS. For a thin-film having a thickness equal to an odd multiple of a quarterwavelength and an index of refraction less than that of a substantially-reflective background region, reflection from the portions covered by the thin-film may be minimized.
As explained particularly with reference to Figure 2, the color of the thin-film region may be modified by changing its thickness. Thus, in a reflective display like that of Figure 4, one may have a substantially white background region and a monochrome (substantially black or one of a range of colors) for the portions covered by the thin film.
The intensity of the monochrome regions may be modified by providing them with sub-visible reflective sub-portions (absence of thin film) according to a predetermined half-tone image.
Claims (14)
1. A permanent gray-scale reproduction comprising, in combination, a background region of refractory material, and refractory thin-film means located over portions of said background region for producing in cooperation with said background region a predetermined image including a half-tone image.
2. A permanent gray-scale reproduction in accordance with Claim 1 wherein said background region being of a material having a first index of refraction, said thin film-means being of a material having a second index of refraction different from said first index of refraction and located over portions of said background region for producing in cooperation with said background region a predetermined image including said half-tone image.
3. A permanent gray-scale reproduction in accordance with Claims 1 or 2 wherein said thin-film means has at least two different thicknesses.
4. A permanent gray-scale reproduction in accordance with any one of Claims 1 to 3 wherein said background region is substantially transparent.
5. A permanent gray-scale reproduction in accordance with Claims 1, 2 or 3 wherein said background region is substantially reflective.
6. A permanent gray-scale reproduction in accordance with any one of Claims 1 to 5 wherein said thin-film means comprise a thin-film layer disposed on said background region and said layer contains a plurality of apertures whose dimensions are proportional to the local intensity of said predetermined image.
7. A permanent gray-scale reproduction in accordance with any one of Claims 1 to 6 wherein said background region comprises surface morphological means for modifying its reflectance.
8. A permanent gray-scale reproduction in accordance with any one of Claims 1 to 7 wherein said thin-film means comprise a substantially transparent insulator.
9. A permanent gray-scale reproduction in accordance with any one of Claims 1 to 8 wherein said thin-film means has a thickness in the range 50 to 1000 nanometers.
10. A permanent gray-scale reproduction in accordance with any one of Claims 1 to 9 wherein said background material is chosen from the group consisting of silicon, germanium, gallium arsenide, sa#pphire and alumina.
11. A permanent gray-scale reproduction in accordance with any one of Claims 1 to 10 wherein said thin-film means are chosen from the group consisting of silicon nitride, silicon monoxide, silicon dioxide, alumina, tantalum oxide and titanium oxide.
12. A method for forming a permanent greyscale reproduction, the method comprising providing a refractory background region material, forming refractory thin-film means over portions of said material for producing in cooperation therewith a predetermined image including a half-tone image.
13. A method for forming a permanent grayscale reproduction in accordance with Claim 12 comprising:
providing said background region material to have a first index of refraction; and
forming said thin-film means to have a second index of refraction different portions of said background region material for producing in cooperation with said background region material a predetermined image including said half-tone image.
14. A method for forming a permanent grayscale reproduction including a half-tone image comprising:
providing a background region material; and forming said refractory thin-film means correspond- ing to said half-tone image over said background region material.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US22116780A | 1980-12-29 | 1980-12-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2090428A true GB2090428A (en) | 1982-07-07 |
| GB2090428B GB2090428B (en) | 1985-06-12 |
Family
ID=22826643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8128652A Expired GB2090428B (en) | 1980-12-29 | 1981-09-22 | Permanent gray-scale reproductions including half-tone images |
Country Status (3)
| Country | Link |
|---|---|
| FR (1) | FR2497368B1 (en) |
| GB (1) | GB2090428B (en) |
| IT (1) | IT1219782B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006034600A1 (en) * | 2004-09-29 | 2006-04-06 | 3D Ag | Archiving means for permanently storing optically recognisable information |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2904432A (en) * | 1954-09-29 | 1959-09-15 | Corning Glass Works | Method of producing a photograph in glass |
| US3771857A (en) * | 1971-04-19 | 1973-11-13 | Optical Coating Laboratory Inc | Striped dichroic filter and method for making the same |
| DE2658623C2 (en) * | 1976-12-23 | 1982-07-29 | Dr. Johannes Heidenhain Gmbh, 8225 Traunreut | Recording media and process for its manufacture |
| DE2903641C2 (en) * | 1979-01-31 | 1982-11-11 | Dr. Johannes Heidenhain Gmbh, 8225 Traunreut | Process for producing a recording medium with a pattern which appears in at least two different colors when irradiated with light |
-
1981
- 1981-09-22 GB GB8128652A patent/GB2090428B/en not_active Expired
- 1981-10-02 FR FR818118610A patent/FR2497368B1/en not_active Expired
- 1981-12-23 IT IT68670/81A patent/IT1219782B/en active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006034600A1 (en) * | 2004-09-29 | 2006-04-06 | 3D Ag | Archiving means for permanently storing optically recognisable information |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2497368B1 (en) | 1989-09-29 |
| IT8168670A0 (en) | 1981-12-23 |
| FR2497368A1 (en) | 1982-07-02 |
| GB2090428B (en) | 1985-06-12 |
| IT1219782B (en) | 1990-05-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950922 |