JPS5928892B2 - Method for manufacturing a diffraction subtractive color filter embossing master plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a diffractive subtractive color filter having a plurality of individual micro-images embossed thereon, in particular a diffractive subtractive color filter embossing master. The present invention relates to a method for producing transparency images useful for recording such micro-image information.

The microimage information is recorded on an original in microfiche, microfilm, or other desired format. Regarding the diffraction subtractive color filter technology, Mr. Karl Knop, one of the inventors of the present invention,
) in US Pat. No. 3,957,354. Regarding the black-and-white diffraction subtractive optical filter, Mr. Gale (Mi
US Pat. No. 40, issued to Chael T., Gale)
No. 62628. As shown in these patents, a relief pattern of diffractive subtractive structures embossed into the surface of a transparent thermoplastic film filters incident white light and produces a predetermined hue ( For example, it is used to generate a zero diffraction order representing a subtractive primary color) or a neutral black (low intensity output with no discernible color). In particular, the hue can be extracted well by a rectangular diffraction grating. In this grating, the specific color represented by the zero diffraction order is primarily a function of the depth of the grating. On the other hand, a neutral black filter is extracted by two intersecting sinusoidal gratings with different specific depths. clay scale (
The black-and-white diffraction subtractive color filter uses mesh plate processing to extract the area (where a diffraction grating exists) representing black within each resolvable image element of the black-and-white filter.
and by changing the relative proportions of the area representing white (the area without the diffraction grating).

In this case, the dimensions of the area representing white or the area representing black are sufficiently small that they cannot be resolved during readout, but still large compared to the line spacing of the diffraction grating. The degree of saturation represented by the filter representing the color image is likewise controlled by the grid processing. Furthermore, in the case of color images,
Typically, different subtractive primaries (cyan, magenta,
It is necessary to properly match the three filters, each corresponding to a color (yellow). Therefore, only one embossed master plate is required to construct a black-and-white diffractive subtractive color filter, but three separate embossed master plates are usually required to construct a full-color diffractive subtractive color filter. Requires embossed original plate. 197
Pelkey Patent No. 853,282, issued October 5, 1997, and assigned to the same applicant as the present application, describes a method for producing a diffractive subtractive filter embossed master plate.

This diffractive subtractive color filter embossed original plate is made of four different recording substrates (one each corresponding to black and one of the three subtractive primary colors).
made from any one of the planks). The recording substrate is a metal foil with an appropriate diffraction grating relief structure (sine wave in the case of black, rectangular wave of appropriate depth for each color in the case of the three primary colors) on one side of the metal foil. Made of foil.
Furthermore, the recording substrate has a layer of photoresist covering the surface of this foil. Image information is recorded on the substrate by selectively exposing photoresist with this image information. This is typically accomplished by contact printing a transparency containing image information onto the photoresist.
Selectively remove the photoresist from areas that represent white image information using a suitable photoresist developer, remove the grating from only those areas that represent white, and then remove the remainder of the photoresist using a suitable solvent. The original version is constructed by removing it. This is particularly characteristic when the image information contained on the transparent image is a group of micro-images processed by mesh plate processing and arranged in a predetermined form, such as a micro-fissure. Each micro-image on the transparency is generated from a separate larger image, such as a color painting, a black and white painting, or an image containing both color and black and white parts. The present invention relates to a processing method and apparatus for producing a meshed microphone mouth image transparency for use in constructing a diffractive subtractive filter embossing master. This invention primarily applies to continuous tone (clay scale) that requires partial or total color or cross-plating.
related to image information that is either black or white.

Linear black and white image information (textbooks, line drawings, etc.) that is high contrast but does not require grid processing is processed using the techniques of the present invention. It is generally easier and cheaper to use more direct processing to handle such high contrast, linear black and white materials. Hereinafter, this invention will be explained in detail with reference to the drawings.

As shown in FIG. 1, three diffractive subtractive color filter embossed original plates 110c, 110m, and 110y (corresponding to each color component of cyan, magenta, and yellow) are used to create a microfiche from a set of each large color image. generated in the form.

The color image 100 may be a photographic transparency or, as is often the case, cross-plated (halftone)
It may be a magazine that is a four-color (three primary colors and black) color print or a book that is already published, such as a book image. Furthermore, color printed matter may include solid black material, such as textbooks, printed directly over it. Typically, such color prints have printed pages of dimensions, for example 21x30c7n, and are processed with a grid of about 50 lines/cm (about 170 micron pitch). Generally, in microfiche format, the size of each color image is reduced to about 1/20th.

In particular, the first microfiche format consists of 60 images, each reduced by a factor of 18. The second microfiber format consists of 60 or more images, for example 98 images, but the size of the images is reduced by a factor of 24. As mentioned above, the embossed original substrate for color filters consists of a rectangular wave diffraction grating formed on the surface of a metal substrate.
The above surface is covered with a layer of photoresist.

Each grid of the substrates of masters 110c, 110m, and 110y each has a different depth that determines the hue (cyan, magenta, or yellow) of the subtractive primary color represented by it. Master 110c, 110m and 1
The grating depth and line spacing used by 10y is typically 1 to 2 microns. According to the invention, the image information saturation of the microfissure image is provided by very fine dots, preferably with a center-to-center distance of about 10 microns. Fully saturated color is represented by the presence of a grating over the entire dot unit area. The saturation of color image information within any dot unit area is determined by the percentage of the total dot unit area covered by unerased gratings.
To obtain a good clay scale, the area of the total dot unit covered by the unerased grating should vary from 100 percent to a value of about 5 percent. Embossed original plate 110c, 1
Since 10m and 110y use a fine mesh pattern, there is a problem with undesirable moiré patterns when the original color image 100 contains material that has already been meshed.

(The original printed mesh board treatment was not sharp enough to separate the colors and reduce the individual mesh dot patterns). For this reason, the embossed original plates 110c, 110m
It is necessary to remove any grid pattern already present in the color image 100 before the new fine grid pattern required by and 110y is introduced. Moreover, this must be done without significant loss in resolution of the color image information. In order to achieve this, the required total reduction ratio is achieved by sequentially reducing the image size of the image in the first and second stages. In the first step, the dimensions of the color image are reduced to some intermediate dimension. In a subsequent second step, this intermediate dimension is further reduced and converted into a microfissure image dimension. It is desirable to select a standard film size such as 35m1L or 70mm as the intermediate size.

35mm film has the advantage that it requires less film to handle than 70mu film, and processing equipment is easier to obtain, but on the other hand, alignment, mesh plate processing, and the resolution required for the film are more stringent. There is also the disadvantage of becoming.

For this reason, the preferred embodiment described herein assumes that the intermediate size is 70 mm film. In particular, each color image 100 is sequentially reduced by a suitable imaging device and imaged onto a strip of color film 102, such as Kodak Internegative Film.

The dimensions of each color image are 21cTn x 30CT! If the No. 11 color film 102 is a 70 mu film, the first stage reduction process will reduce the size by about one-fifth, and the dimensions of the image on the film 102 will be about 40 mm x 56 mm. However, color image 1 that has already been subjected to mesh plate processing
00 is generally screened with approximately 59 lines/C7rL (approximately 170 micron spacing). This initial grid pattern is reduced in color film 102 to images of the grid pattern having spacings of only about 35 microns. The color film 102 emulsion (like most color emulsions today) cannot clearly resolve patterns with 35 micron spacing. Therefore, the reduced original mesh plate pattern is lost, and the moiré problem is solved. However, if a color film with a coarser mesh pattern or higher resolution is used, the image of the mesh pattern on the color film 102 may be obtained by narrowing down the aperture of the projection lens or by slightly shifting the focus. It is necessary to remove it by In either case,
The resolution of the image reduced in the first stage and the resolution of the photosensitive emulsion of the color film 102 are determined by the size of the reduced mesh pattern (35 microns) and the finest image to be preserved or the description in textbooks (text). There must be a difference between the matters. A reduction ratio of approximately 5:1 meets this constraint. That is, this reduction factor is large enough to remove the already existing grid pattern, while at the same time not incurring any significant loss in resolution of image detail. Apart from this, either a color positive film or a color negative film can be used as the color film 102. However, the selection of these two films has some impact on the processing used to perform the next stage color separation, as discussed below. The use of color film strip 102 allows all color images to be treated together as a single film strip rather than as separate individual images.

This simplifies handling and can be processed with normal existing machinery. Furthermore, the standard perforations in the film facilitate alignment so that the position of each image is maintained accurately relative to its adjacent images during all subsequent film contact printing steps. Using a transport mechanism that accurately positions the original film and copy film on the aiming pin, we tested frame-by-frame close-contact printing using a commercially available machine. It was found that a consistent state could be obtained. In addition, more complex alignment methods can also be used, for example using optical markings. As shown in FIG. 1, in the next step, the color film 102 is
Sheets of black and white color separation film 104C (cyan), 104
Contact printing is performed on each of m (magenta) and 104y (yellow).

Each of the film strips 104C, 104m, and 104y is made of continuous tone (low gamma) panchromatic black and white film. color using white light passing through a red filter.
By contact printing from film 102, cyan is color separated on film strip 104c. Similarly, magenta color separation is achieved by contact printing on film strip 104m using white light passing through a green filter, and contact printing on film strip 104y using white light passing through a blue filter. By doing this, yellow color separation is performed. An ideal (theoretical) filter for perfect color separation would need to have negative transparency, but such a filter is not practical. Additionally, non-ideal spectral transmission must be considered for both color film tint and diffractive subtractive filter gratings. Such problems are well known in the printing industry and are largely solved using special color masking techniques such as those used in this paper. Many commercially available color negative films have masking built into the emulsion formulation and processing.
Positive color films also have lower contrast and require a lower resolution masking film (also made by contact exposure through color film). This masking film is placed in contact with the backside of the color film during exposure for color separation. This is 70m77! It has been demonstrated in practice that good results have been obtained in the 3D format and that there is no significant loss in resolution. 3
Book color separation film strips 104c, 104m and 104y each contain a series of images equal to the number of images in the final microfiche.

The use of precise transport means or fixtures to hold the color and black and white film during exposure ensures alignment of the image with the film perforation. Although not required, this alignment is most accurately and conveniently achieved by performing a frame-by-frame exposure (equipment for this task is commercially available). Next, black and white films for color separation 104c, 104
By contact printing 104y and 104y, it is necessary to transfer them to black and white, high contrast, mesh-treated color separation films 106c, 106m and 106y, respectively.

After the second stage reduction process of about 1/4 (color image 100
to the embossing master plates 110c, 110m, and 110y), the film strip 10
Approximately 4 in medium size size consisting of 6c, 106m, 106y
It is necessary to form a 0 micron mesh plate pattern. In a typical print job, as mentioned above, approximately 59 pieces/C:7
A mesh plate of RL (170 micron spacing) is used.

Approximately 118 pieces/? It is also possible to obtain a finer mesh board, but even this finer commercially available mesh board is approximately 8.
The spacing is 5 microns, which is more than twice the required mesh plate spacing (approximately 40 microns). Furthermore, if matching is required, any one of the color separation films 104c, 104m, 104y with each continuous tone, rather than a mesh plate, may be used.
106c, 106m, respectively.
High contrast used to generate 106y (
Techniques of direct contact with the recording film (high gamma) are advantageous. These problems are solved by using a commercially available close-fitting mesh plate of 59 wires/CfrL in a non-conventional manner, as shown in FIG.

In particular, continuous tone image color separation strips 104 (104c, 10
4m, 104y) is placed in direct contact with the high contrast black and white film 106. 59/0fIL commercially available close-fitting mesh board 2- installed away from this
00 is irradiated by the diffused light 202 for irradiation. This illumination diffuser 202 is obtained by an array of fluorescent lamps placed behind the diffuser means. The pattern 204 of the mesh-treated light coming out of the mesh plate 200 is divided into 1/2 by the lens 206.
film strip 10 with a reduction factor slightly greater than 4
imaged on a plane that coincides with the continuous tone image plane on 4;
printed. The lens 206 is a high-performance lens (
For example, Nippon Kogaku 150m77! ．． F5.6 lens) is used. The high contrast black and white film 106 is sufficiently high to limit the area of the screen dots to about 5% of a unit screen area (i.e., a unit screen having a linear dimension of about 9 microns and a spacing of about 40 microns). It must have high resolution. KodallthSup manufactured by Eastman Kodatsu
KOdalithOrthO film 3 developed with er) RT developer was found to meet the above requirements. To have high contrast and still obtain final resolution, a recording medium such as chrome film coated with photoresist on plastic can be used. In this case, the photoresist is exposed, developed, and the chrome is etched to obtain a high contrast pattern. Here, a magenta screen and/or a fine halftone screen such as an oval dot screen may also be used. The technique shown in FIG. 2 is essentially a contact print of a continuous tone image, uses illumination through a halftone screen, and is capable of obtaining good clay scale. Contact printing has the advantage that alignment of the image with the perforation of the film can be maintained. Conventional contact printing equipment can be easily modified to accommodate this operation by modifying the illumination device to cooperate with the mesh plate and projection lens. It should be noted that the textbook (text) surfaces and line drawings in image 100 are also screened by the technique described in section X.

This is common practice in the printing industry, as it takes to break down the textbook (text) into image areas of continuous tones before cross-plate processing, and to re-soften it after cross-plate processing. Necessary to save cost and time. It has been found that textbooks can be reproduced very well if the height of the letters is at least 2-3 mesh spacing. Representative 21? For a x30 cTrL printed page, the minimum character height is about 1 mm. If this is reduced to 1/5, the height of the character will be approximately 200 microns, which is 4
A mesh plate with a spacing of 0 microns meets this requirement. Other techniques for screening continuous tone images may also be used.

For example, tight meshes as large as about 237 lines/CTIL (about 40 microns) or about 985 lines/CTfL (about 10 microns) can be formed by careful selection of mesh plate recording techniques and materials. However, the above techniques only use existing mesh plates and recording materials. A continuous tone image film strip 104 is produced using a gray contact image screen projected onto the color film in contact with a panchromatic lithographic film with red, green, and blue illumination.
It is also possible to combine the technique of producing the mesh plate separation film strips 106c, 106m, 106y with the technique of producing the mesh plate separation film strips 106c, 106m, 106y. Such techniques are well known to those skilled in the art and can also be applied in this invention.
However, the method shown in FIG. 1 is particularly preferred. Referring again to FIG. In the next step, a second reduction by about 1/4 is carried out, and at the same time the 70 mm film strip is converted to a microfissure transparency. Particularly high contrast, mesh plate treated color separation film 106c, 10
6m and 106y are each reduced to 1/4 and made using diazo film (for example, ScOtt Graphics Co., Ltd.).
G-41 released by Graphies Inc.
．． A high resolution recording medium such as P4C, diazo contact copying film, or other commercially available diazo film for making micro films) is then imprinted. The image is formed on the diazo film+ in the final microfissure arrangement. Accurate alignment is required to maintain alignment between images. An apparatus for accomplishing this alignment is shown in FIG. As shown in FIG. 3, each frame of film can be successively positioned over the projection lens 306 by accurately feeding the film using pins 300, 302 located at film feed holes 304. . Diazo film
Sheet (usually about 10 (size: 7L x 15?)
1. Accurately setting the position using the moving means 308;
Images reduced to /4 can be accurately projected to predetermined positions, and each image can be moved to a new position.
By this method, each film strip 106c, 106m,
All the images on 106y are microfissure transparent images 108c, 10 with exact positional relationships between the images.
8m, 108y. 70m
For the m-film strips 106c, 106m, 106y, a positional accuracy of approximately 20 microns is obtained, and for the microimaging diazo film, which is reduced in total by 1/24, an accuracy of 5 microns is obtained.

Each diazo microfissure transparent painting 108c, 108
m, 108y are contact printed onto the corresponding embossed master substrate by using blue or ultraviolet light.

This substrate is developed, for example, by the method shown in Pelkey Patent No. 853,282 mentioned above, and the grating relief on the surface is selectively erased by electroplating.
Desired embossing original plates 110e, 110m, and 110y are obtained. Alternatively, microfissure transparency 108
c, 108m, and 108y are omitted, and the color separation film strips 106c, 106m, and 106y, which have been subjected to mesh plate treatment by irradiation with a mercury lamp (ultraviolet light), are directly applied to the original plate base 1.
It can also be reduced to 10c, 110m, and 110y.

By using positive or negative color film 102, images of opposite polarity can be produced on the final embossing master 110.

This polarity (positive or negative) is determined by steps 104, 106,
It depends on the media and processing used in 108 and the format of the master substrate. If this polarity is unsuitable, the above polarity can be corrected by adding a contact printing step, preferably by contact printing on a high contrast black and white reversal processed film with a mesh plated black and white separation process. Can be reversed. In addition to image-by-image alignment, all images must be accurately positioned with respect to alignment finger points on each of the three microfissure masters 110c, 110m, 110y.

It produces cyan, magenta and yellow plastic.
Replicas can be easily aligned. The finger points can be, for example, optical marks, perforations, or a group of grooves or raised lines formed on the original substrate. A tongue-shaped and grooved structure that is in the original substrate and is therefore on the original and is embossed into the replica.
A width of about 200 microns and a depth of about 80 microns) can provide excellent alignment (alignment down to several microns). Good replicas of images and textbooks (text) can be obtained by superimposing cyan, magenta and yellow replicas.

The fourth black replica was found to be less important in improving image quality, so it is not included in the preferred arrangement shown in FIG.

In principle, a fourth black replica could be added to the three-color replica in a manner similar to that used for regular four-color prints. By making some modifications to the process of Figure 1, the technique of Figure 1 can be applied to a set of 100 color images.
It can also be used to generate a diffractive subtractive filter embossed master from a set of separate continuous tone black and white images rather than from a set of separate continuous tone black and white images.

In this case, no color separation is necessary and only a single embossed master substrate with a sinusoidal diffraction structure is used instead of a three-color separation substrate with a rectangular diffraction structure. Furthermore, instead of the color film 102 of FIG. 1, continuous tone, low gamma,
Black and white film (color separation film 104c, 10 in Figure 1)
Similar to the one used for 4m, 104y)
is used. Since black-and-white film has a higher resolution than color film, the above-mentioned method for removing the mesh already present in the original image cannot be used in the black-and-white case. Instead, a mesh plate 200 is used to prevent moiré patterns from occurring in black and white cases.
is rotated so that the lines of the screen plate 200 are oblique to any lines already present in the continuous tone image. This prevents visible moiré patterns from appearing in the screened image produced on the high contrast black and white film corresponding to film 106. If desired, a strip of microfilm may be used in place of the microfissure transparency shown in FIG.

Alternatively, commercially available contact printing and processing equipment has approximately 30
? Since it is possible to process sheets with dimensions of X5O (7 rL), a large film sheet (
About 30? ×5001rL) can also be used. Although in principle the contact printing process could be replaced by a 1:1 (or other ratio) projection process, contact printing is simpler and more reliable. As mentioned above, the 35mm format is disadvantageous in terms of alignment, mesh plate processing, and increasing the required resolution of the film, but these three
5mTL intermediate format can also be used instead of 70mm format.

In this case, the first stage reduction ratio is approximately 10, and the second stage reduction ratio is approximately 2. Next, the basic structure and preferred embodiments of the method according to the present invention and an apparatus capable of carrying out the method will be listed. (1) A method for producing a finely meshed diffractive subtractive filter embossed master plate containing micro-image information of a predetermined type from a plurality of individual images of relatively large dimensions that have already been meshed, the method comprising: a first reduction ratio that reduces all of the plurality of images having large dimensions to an intermediate dimension between the large dimension and the final micro-image dimension, the first reduction ratio being present in the large dimension images; recording each successive tone on the first medium with a reduction factor of sufficient magnitude such that any mesh pattern is reduced such that it cannot be resolved in the intermediate dimension; transferring each meshed image of the toned image with the intermediate dimensions onto a high-contrast medium in the certain form and with a predetermined mesh spacing; recording the predetermined form on a second medium at a second reduction rate to a micro image size.

2) The method for producing a diffractive subtractive color filter embossing original plate according to (1), wherein the reduction ratio in the first step is about 5.

3) The method for producing a diffractive subtractive color filter embossing original plate according to (1), wherein the reduction ratio in the first stage is about 5 and the reduction ratio in the second stage is about 4.

4) The diffractive subtractive color method filter embossed original plate according to (3), wherein the screen-treated image is transferred with a predetermined mesh spacing of about 40 microns, so that the mesh spacing of the final micro image is about KlO microns. manufacturing method.

5) The method for producing a diffractive subtractive filter embossing original plate according to (1), wherein the reduction ratio in the first step is about 10.

3) The method for producing a diffractive subtractive color filter embossing original plate according to (1), wherein the reduction ratio in the first stage is about 10 and the reduction ratio in the second stage is about 2.

7) The large size image is a color image and the first recording step is recording in a mold on a color film at a first reduction ratio and using light of subtractive primary colors. Diffractive subtractive color method type according to (1), comprising the step of contact printing the color film on a panchromatic black and white film, thereby recording each image in continuous tone and color separation on the above certain type having intermediate dimensions. A method of manufacturing a pressed master plate.

8) The transfer step consists of contact printing the continuous tone second medium directly onto the high contrast second medium with a screen pattern of projected illumination light having a predetermined screen spacing. (1) A method for producing a diffractive subtractive color filter embossing original plate.

9) An apparatus for producing a diffractive subtractive color filter embossing original plate of micro image information having a predetermined shape, which comprises a printing mesh plate having a predetermined first interval, and a printing mesh plate having a predetermined first interval; means for irradiating the mesh plate with diffused light installed on one side; and a lens installed on the other side of the mesh plate, the means for irradiating the mesh plate with diffused light;
a reduction projection lens for producing a grid pattern of light having a second spacing reduced by a predetermined ratio with respect to the spacing of the image forming apparatus; and a high contrast photosensitive recording medium disposed substantially within the projection plane. and means for contact printing a continuous tone image thereon in the light grid pattern.

(9) The apparatus for producing a diffractive subtractive filter embossing original plate according to (9), wherein the first interval is about 170 microns.

(9) The apparatus for producing a diffractive subtractive color filter embossing original plate according to (9), wherein the first interval is about 170 microns and the second interval is about 40 microns. (Own) An apparatus for producing a diffractive subtractive color filter embossing original plate according to (Own), wherein both the continuous tone image recording medium and the high contrast photosensitive recording medium are 70 mm films.

(Own) An apparatus for producing a diffractive subtractive color filter embossing original plate as described in (Own), wherein the continuous tone image recording medium is comprised of a 70 mm film, and the high contrast photosensitive recording medium is comprised of a chromium layer covered with photoresist.

[Brief explanation of the drawing]

FIG. 1 is a process diagram explaining the processing method of the present invention, FIG. 2 is a schematic diagram of an apparatus for producing the color-separated black and white film subjected to the mesh plate processing shown in FIG. 1, and FIG. 1 is a schematic diagram of an apparatus for making a fish transparency; FIG. 100...Color image, 102...Color film, 104c, 104m, 104y...
...Color separation film strip, 106c, 106m, 10
6y...Film strip treated with black and white mesh plate, 108c, 108m, 108y...Microfissure, 110c, 110m, 110y...
・Diffraction subtractive color method filter embossed master plate, 200...
Mesh plate, 202...Irradiation light.

Claims (1)

[Claims] 1. A method for producing a diffractive subtractive color filter embossed original plate containing a predetermined type of micro-image information and finely meshed from a plurality of individual images of relatively large dimensions that have already been meshed, the method comprising: A first reduction rate for reducing all of the plurality of images initially having large dimensions on one medium to a size intermediate between the large size and the final micro-image size; recording in a form of continuous tone at said reduction rate sufficient to reduce any grid pattern present in the image to a size that cannot be resolved in said intermediate dimension; transferring the cross-plated image of each continuous tone image on the medium of 1 with the intermediate dimensions to the mold on a high-contrast medium with a predetermined mesh spacing; recording each image in said predetermined mold on a second medium at a second reduction rate to reduce said image to said final micro-image size; Each image is
transfer from the medium by exposure to an embossed original base material on which a diffraction grating relief is formed and whose surface is covered with a photoresist layer, and develop the exposed embossed original base material, and then transfer the embossed original plate material to the embossed original base material, which has a diffraction grating relief formed thereon and whose surface is covered with a photoresist layer. forming an embossed master by selectively erasing the diffraction grating relief on the surface of the substrate.