JP4290077B2 - Color image forming method and color image - Google Patents

Description

  The present invention relates to a color image forming method and a color image using a plurality of diffraction gratings.

  A method for forming a color image by combining diffraction gratings corresponding to the three primary colors (RGB) is already known (see, for example, Patent Document 1). A color image forming method is also known in which a color to be expressed in one pixel is expressed by a combination of a plurality of diffraction gratings having different spectra observed in a specific direction (see, for example, Patent Document 2). ).

US Pat. No. 817,569 U.S. Pat. No. 4,788,116

  However, the color image according to the above-mentioned document expresses a desired color by forming a screen exclusively for the diffraction grating regardless of the color to be displayed on each of the three primary color diffraction gratings and then applying a mask. Therefore, a mask-dedicated screen and a mask preparation process are required before obtaining a final color image after the formation of the diffraction grating, and there is also a problem related to the alignment with the diffraction grating-dedicated screen even after the mask-dedicated screen is formed. In addition, since the diffraction gratings corresponding to the three primary colors are combined for color image formation by photographing, it takes time and effort to form a color image.

  Therefore, an object of the present invention is to provide a color image forming method using a plurality of diffraction gratings by a method different from the conventional one.

  The present invention solves the above-described problems by the following method. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiments.

According to the color image forming method of the present invention, a plurality of diffraction gratings (GR, GG) having different spectra observed in a specific direction for colors to be expressed in each of a plurality of pixels (P) constituting a predetermined color image. , GB) method of forming a color image (1) be represented by a combination of the number of divided areas (Da equal to each pixel of the plurality of diffraction gratings, Db, divided into Dc), before Symbol multiple Each of the diffraction gratings is assigned to each of the plurality of divided regions on a one-to-one basis, and the diffraction gratings corresponding to the divided regions to which the diffraction gratings are assigned are assigned to the pixels in accordance with the color to be expressed by the pixels . The above problem is solved by changing the area ratio to form each diffraction grating in the allocated divided region.

  According to the color image forming method of the present invention, for each of a plurality of diffraction gratings having different spectra observed in a specific direction, the area ratio with respect to the divided region in which each diffraction grating is formed depends on the color to be expressed. Different colors are expressed by changing. Accordingly, a different color for each pixel in the specific direction is obtained by the spectrum of the plurality of diffraction gratings, and a color image in which the color to be expressed in each pixel is expressed. If a plurality of types of diffraction gratings are selected so that they can be displayed in full color, a full color hologram image can be obtained when observed from a specific direction.

  Further, the plurality of diffraction gratings used are not limited to those corresponding to the three primary colors. By combining a number of diffraction gratings of three or more primary colors, the color reproduction range can be further expanded. In addition, since the color of the diffraction grating can express a high-purity color, it is a beautiful color that far exceeds the color reproduction range of conventional printing methods, such as blue-green near 480 nm and deep green near 510 nm. Can be reproduced.

  “Spectrum” means a state where light is split into a plurality of wavelengths (colors). For example, as a plurality of diffraction gratings, a diffraction grating in which a red wavelength is observed in a specific direction, and a green wavelength is When the observed diffraction grating and the diffraction grating in which the blue wavelength is observed are respectively assigned to the divided regions, colors obtained by combining these colors by an additive color mixing method can be expressed with respect to the specific direction.

  In the color image forming method of the present invention, for each of the plurality of diffraction grating original plates (10-1, 10-2, 10-3) on which the respective patterns of the plurality of diffraction gratings are formed, the diffraction grating original plate is used. The pattern is formed by superimposing the transferred image (11) on which the color image is to be formed, irradiating the overlapping portion with an energy ray (L), and melting the surface of the transferred object based on the heat. A position corresponding to the divided area is transferred by moving the energy beam so that the pattern is transferred to a position corresponding to the divided area assigned to the diffraction grating in the transferred body. The diffraction gratings may be formed sequentially.

  The range irradiated by energy rays is small and easy to cool. Therefore, the cooling process can be greatly shortened without preparing a special cooling device, and the color image drawing speed using a plurality of diffraction gratings can be improved. Further, by controlling the energy beam by a program such as a computer, it is possible to improve the drawing accuracy and resolution of a plurality of color images. The “energy rays” include both those that have heat such as so-called heat rays and those that do not have heat. For example, a laser, an electron beam, a microwave, etc. are included. Therefore, “heat based on energy rays” includes heat due to heat possessed by the energy rays themselves and reaction occurring at the irradiation position of the energy rays, for example, heat caused by electron activation or chemical reaction.

  For example, a melted layer made of a material that is melted by heat based on energy rays is provided on the surface of the transfer object, and the melted layer and the diffraction grating original plate are overlapped so that the portion melted by heat based on energy rays It is possible to transfer the pattern of the diffraction grating master superimposed on the substrate. In addition, the mode of irradiating the superimposed transfer target and each diffraction grating original plate with energy rays includes a mode of irradiation from the transfer target side and a mode of irradiation from the diffraction grating original side. The same energy beam may be used for pattern transfer of each diffraction grating, or different energy beams may be used.

  The plurality of divided regions in the color image forming method of the present invention may be regions in which the rectangular pixels are equally divided in the vertical direction. Accordingly, the divided regions to which the same diffraction grating is assigned can be continued in the vertical direction, and the diffraction gratings assigned to the divided regions can be continuously formed in the vertical direction for each divided region. Therefore, it becomes easy to control the energy beam when forming the diffraction grating.

  Further, the direction in which the area ratio of the diffraction grating formed in each of the plurality of divided regions changes according to the color to be expressed may be the same. Thereby, it becomes easy to control the energy rays when changing the area ratio of the diffraction grating formed in each divided region in accordance with the color to be displayed.

  The color image of the present invention is a color image in which the color to be expressed in one pixel (P) is expressed by a combination of a plurality of diffraction gratings (GR, GG, GB) having different spectra observed in a specific direction. (1) The pixel is divided into a plurality of divided regions (Da, Db, Dc), and each of the plurality of diffraction gratings is formed in each of the plurality of divided regions. The problem described above is solved by the fact that the area ratio of the diffraction grating formed in the divided region to the divided region differs depending on the color to be expressed.

  According to the color image of the present invention, as described above, a color image in which the color to be expressed in each pixel is always expressed in a specific direction can be obtained. If a plurality of diffraction gratings are selected so that they can be displayed in full color, a full color hologram image can be obtained when observed from a specific direction. The interpretation of “plurality of diffraction gratings” and “spectrum” is as described above.

  As described above, according to the present invention, in each divided region, the diffraction grating is formed so that the area ratio of the diffraction grating formed in the divided region to the divided region changes according to the color to be expressed. By forming in the divided area, it is possible to provide a color image forming method using a plurality of diffraction gratings by a method different from the conventional method.

  FIG. 1 is an enlarged view showing one pixel P of a color image in one embodiment of the present invention. The pixel P has three divided areas Da, Db, and Dc that are equally divided into three in the vertical direction A. In each of the divided areas Da, Db, and Dc, diffraction gratings are formed in which different spectra are observed in a specific direction. Therefore, the color obtained by the additive color mixing method can be expressed with respect to the specific direction. Hereinafter, each wavelength (color) obtained by light spectroscopy is referred to as “spectrum”. In this embodiment, a diffraction grating GR capable of observing a red spectrum R with respect to a specific direction is formed, a diffraction grating GG capable of observing a green spectrum G is formed in the divided area Db, and a blue spectrum is formed in the divided area Dc. A diffraction grating GB capable of observing B is formed. Hereinafter, red, green, and blue may be collectively referred to as “RGB” or “RGB color”.

  Hereinafter, when it is not necessary to distinguish the divided areas Da, Db, and Dc, they are simply referred to as a divided area D, and when it is not necessary to distinguish the diffraction gratings GR, GG, GB, they are simply referred to as a diffraction grating G. For convenience of explanation, FIG. 1 shows the boundary line of the divided region D, but it is not actually formed. The above three divided regions D are provided in all the pixels P constituting the color image. Hereinafter, the diffraction grating G formed in each divided region D will be described.

  In each divided region D, a diffraction grating G is formed with a predetermined area ratio. The area ratio of the diffraction grating G formed in each divided region D differs depending on the color to be expressed by each pixel P. The area ratio is the ratio of the diffraction grating G formed in the divided region D to the divided region D. A method for forming each diffraction grating G will be described later. For example, the pixel P shown in FIG. 2 and the pixel P shown in FIG. 1 have different area ratios of the diffraction gratings G, and therefore express different colors. In this embodiment, as shown in FIG. 2, the area of the diffraction grating G formed in each divided region D changes in the vertical direction A according to the change in the area ratio, and the divided region whose area ratio is less than 1. In D, there is a non-formed portion S where the diffraction grating G is not formed.

  In this embodiment, the spectrum R has a wavelength of 650 nm, the spectrum G has a wavelength of 545 nm, the spectrum B has a wavelength of 450 nm, and the diffraction grating pitch of the diffraction grating G that can observe each spectrum R, G, B in a specific direction is 1.3 μm, 1 .1 μm and 0.9 μm.

  In FIG. 3, the conceptual diagram of the color image 1 comprised by the above-mentioned pixel P is shown. Since the color image 1 of this embodiment has the above-described divided area D in all the pixels P, the color image 1 is divided into strips in the vertical direction A by the divided area D. That is, the color image 1 has a strip-shaped continuous divided area CDa in which the divided areas Da are continuous in the vertical direction A, a strip-shaped continuous divided area CDb in which the divided areas Db are continuous, and a continuous strip-shaped in which the divided areas Dc are continuous. Divided into divided regions CDc.

  Hereinafter, the continuous divided areas CDa, CDb, and CDc are simply referred to as continuous divided areas CD when it is not necessary to distinguish them. In this embodiment, the pixel P is a square having a side length W1 of 60 μm, and the width W2 of the divided region D is 20 μm. In the continuous divided region CD corresponding to the same spectrum, the interval W3 of the center position of each continuous divided region CD exists every 60 μm in the horizontal direction B.

  In the color image 1 of FIG. 3, the diffraction grating G is continuously formed in all the continuous division regions CD for convenience of explanation, but actually, the area of the color to be expressed by the pixel P The non-forming portion S described above exists for each pixel P because it is formed according to the rate. Therefore, the continuous division region CD is not always formed continuously in the vertical direction A. The appearance of the continuous division region CD in the actual color image 1 is shown in the enlarged view of the color image 1 in FIG. The continuous division regions CD corresponding to each RGB are arranged, and in each continuous division region CD, the diffraction grating G is formed according to the area ratio as described above, so that it looks like dotted.

  Next, a method for forming the color image 1 shown in FIG. 3 will be described. In this embodiment, first, each pixel P of the original color image is expressed in RGB colors. For example, it may be expressed in RGB mode using existing graphic software. Each of the RGB colors is determined as to which of the 0 to 255 brightness values. By referring to the brightness value / area ratio conversion table created in advance, the area ratio of each diffraction grating G corresponding to the brightness value of each RGB color is obtained. The luminance value / area ratio conversion table is a table in which each luminance value of 0 to 255 and the area ratio of each diffraction grating G are associated with each other in a one-to-one correspondence, and are created in advance by calculation or experiment.

  A method of forming each diffraction grating G based on the area ratio obtained for each diffraction grating G of each pixel P in this way will be described. In this embodiment, as shown in FIG. 5, a laser image L is irradiated as an energy beam, and the pattern of the diffraction grating original 10 is transferred onto the transfer body 11 to form the color image 1 on the transfer body 11. First, the diffraction grating original plate 10 and the transfer target 11 are adsorbed to the outer peripheral side surface of the drum 12 rotating in the direction R by vacuum suction, and the laser L is irradiated toward the transfer target 11.

  By rotating the drum 12 in the direction R, the laser L can be irradiated in a line shape in the vertical direction A with respect to the transfer target 11. This line is hereinafter referred to as “irradiation line”. By moving the laser L in the horizontal direction B with the drawing direction as the drawing direction, it is possible to draw an irradiation line on the transfer target 11 at a predetermined pitch. FIG. 5 shows that the third irradiation line is irradiated. Control relating to the irradiation of the laser L is performed by a computer. The diffraction grating original plate 10 used in this embodiment is a first diffraction grating original plate 10-1 having a concavo-convex pattern of the diffraction grating GR shown in FIG. 6A formed on the surface, and the diffraction grating GG shown in FIG. 6B. These are the second diffraction grating original plate 10-2 having the concave / convex pattern formed on the surface and the third diffraction grating original plate 10-3 having the concave / convex pattern of the diffraction grating GB shown in FIG. Hereinafter, when the diffraction grating original plates 10-1, 10-2, and 10-3 are not particularly distinguished, they are simply referred to as the diffraction grating original plate 10.

  FIG. 8 is an enlarged schematic view of a portion where the transferred object 11 and the diffraction grating master 10 are overlapped. As shown in FIG. 8, the transfer object 11 has a base layer 11a and a molten layer 11b laminated thereon. The molten layer 11 b of the transfer target 11 is overlapped with the surface having the pattern of the diffraction grating original plate 10. The molten layer 11b is composed of wax, a thermoreversible resin, and a high heat conversion material that increases the conversion efficiency from light energy to heat energy of the laser L. The wax and the thermoreversible resin constituting the molten layer 11b may be any material that is solid at room temperature and melts by heating. The base material layer 11a only needs to have heat resistance that does not melt at the melting degree of the molten layer 11b.

  When the melted layer 11b of the transfer target 11 is heated to the melting point and melted by the laser L irradiation, the concave / convex pattern of the diffraction grating original plate 10 is transferred to the melted portion. When the laser L moves, the concave / convex pattern of the diffraction grating original 10 is sequentially transferred to the melted molten layer 11b as the laser L moves. In this manner, the pattern of the diffraction grating original plate 10 is transferred to the molten layer 11b of the transfer target 11. The diffraction grating G is formed on the transfer object 11 by transferring the pattern of the diffraction grating original plate 10. Therefore, if the laser L is irradiated so that the pattern is transferred to a position corresponding to the divided area D assigned to the diffraction grating G, the diffraction grating G can be formed in the divided area D.

  This will be specifically described below. First, the first diffraction grating original plate 10-1 is superposed on the transfer body 11 in the manner described above and adsorbed on the outer peripheral side surface of the drum 12. The irradiation position of the laser L is controlled so that the pattern of the first diffraction grating original plate 10-1 is transferred only to the portion where the continuous divided region CDa is to be formed on the transfer target 11. First, the irradiation position of the laser L is moved so as to be at the upper end of the continuous division region CDa, the irradiation is started, and the drum is rotated in the direction R. Thereby, an irradiation line in the vertical direction A can be drawn on the transfer target 11 by the laser L. By controlling the irradiation of the laser L so that the width of this one irradiation line becomes 20 μm, the diffraction grating GR can be formed on the transfer body 11 as a continuous divided region CDa having a width of 20 μm.

  Further, by controlling the irradiation time of the laser L, the non-forming portion S can be provided in each of the plurality of pixels P arranged in the vertical direction A. The irradiation time may be controlled in accordance with the area ratio obtained for each pixel P, and irradiation may be stopped at a location corresponding to the non-forming portion S. Thus, the pattern of the first diffraction grating original 10-1 can be transferred to the transfer target 11 in the vertical direction A with an area corresponding to the area ratio. That is, a continuous division region CDa constituted by the diffraction grating GR having a different area ratio for each pixel P is formed on the transfer target 11. For example, in the case of a pulsed laser, the oscillation time may be controlled by controlling the irradiation time of the laser L.

  After forming one continuous division region CDa by the laser L, the continuous division region CDa adjacent to the horizontal direction B is formed in the same manner by moving 60 μm in the horizontal direction B. By performing laser L irradiation every 60 μm as described above, a plurality of continuously divided regions CDa... CDa to which the pattern of the first diffraction grating original plate 10-1 is transferred have a width of 20 μm every 60 μm and the transferred object 11. Formed on top. The irradiation intensity, irradiation pitch, and moving speed of the laser L may be set as appropriate according to the constituent material of the molten layer 11b and the constituent material of the first diffraction grating original plate 10-1, and may be controlled by a computer. In this embodiment, control is performed so that the concave / convex pattern of the first diffraction grating original plate 10-1 is engraved into the molten layer 11b at a depth of 0.2 μm.

  After the transfer related to the continuous divided area CDa, the transfer of each pattern of the second diffraction grating original plate 10-2 and the third diffraction grating 10-3 is transferred to the continuous divided area CDa with respect to the continuous divided areas CDb and CDc. The same method is used. As a result, the color image 1 shown in FIG. 3 can be obtained on the transfer target 11. If the transferred object 11 on which the color image 1 is formed is further used as an original plate and the concave / convex pattern formed on the transferred object 11 is transferred to another transferred object by the laser L as described above, the color image can be easily obtained. 1 can be duplicated.

  This invention is not limited to the form mentioned above, You may implement with a various form. For example, each diffraction grating G formed in each divided region D may be formed intermittently without being continuously formed in the vertical direction A as long as the area is the same. This can be realized by controlling the irradiation time of energy rays. Further, as shown in FIG. 9, the area of each diffraction grating G formed in each divided region D may be changed from the vertical direction A to the horizontal direction B according to the area ratio. For example, if a formation method that can control the amount of heat of the laser L to be irradiated is controlled for each pixel P, the change in the area ratio can be expressed by controlling the line width of the irradiation line drawn on the transfer target 11. it can.

  In this embodiment, the pixel P is divided into the three divided regions D. However, the number of the divided regions D in the pixel P may be two or more. The spectrum of the color corresponding to each divided region D may not be red, green, and blue. For example, in the so-called chromaticity diagram shown in FIG. 10, the number of points equal to the number of dividing the pixel P into the divided regions D is set in any place, and the spectrum corresponding to the set position of each point is set in a specific direction. The diffraction grating G to be generated with respect to can be formed in the corresponding divided region D.

  By changing the area ratio of the diffraction grating G formed in the divided region D, the color within the range connecting the points can be expressed by the pixel P. FIG. 10 shows the case where the three points are set to 650 nm, 450 nm, and 545 nm, respectively, and the case where the three points are set to 650 nm, 450 nm, and 515 nm. The former case is the three points selected in the above-described form, and the color range that can be expressed is a color that exists in the triangle 100. On the other hand, in the latter case, the range of colors that can be expressed is a color that exists in the triangle 110.

  The luminance value of each RGB color is not limited to 256 gradations, and may be 256 or more. The area ratio may be obtained by calculation each time in addition to the method of referring to the luminance value / area ratio conversion table. For example, for each of all the colors that should be expressed based on the prior art, the composition ratio of the spectrum of each diffraction grating is obtained, and the area of the diffraction grating that requires a relatively maximum area among a plurality of diffraction gratings from the composition ratio. Is set to 1, the area in each of all the other pixels P is converted for the diffraction grating, and the area ratio of the other diffraction grating in each of all the pixels is obtained based on the converted area and the composition ratio. May be.

  In addition, the formation of the diffraction grating G in the continuous division region CD may not be in the order described above, and may not be formed collectively for each type of the diffraction grating G. The transferred body 11 only needs to be formed of a material whose surface overlapped with the diffraction grating original plate 10 is melted by the laser L, and another layer is provided between the base material layer 11a and the molten layer 11b. It may be.

The figure which shows the pixel as one Embodiment of this invention. The figure which shows the pixel in which the diffraction grating was formed with the area ratio different from the pixel shown in FIG. Schematic of a color image in this embodiment. FIG. 4 is an enlarged view of a part of the color image in FIG. 3. FIG. 4 is a diagram showing a state in which the color image shown in FIG. 3 is formed on a transfer object. (A) is a figure which shows the surface of the 1st diffraction grating original plate, (b) is a figure which shows the surface of the 2nd diffraction grating original plate. The figure which shows the surface of the 3rd diffraction grating original plate. The enlarged schematic diagram of the part which piled up the diffraction grating original plate and the to-be-transferred body. The figure which shows another example regarding the aspect of the diffraction grating which changes with the change of an area ratio. The figure which shows another example regarding the spectrum made to respond | correspond to each division area.

Explanation of symbols

1 Color image p Pixel Da, Db, Dc Divided area GR, GG, GB Diffraction grating

Claims (5)

A color image forming method for expressing a color to be expressed in each of a plurality of pixels constituting a predetermined color image by a combination of a plurality of diffraction gratings whose spectra observed in a specific direction are different from each other,
Wherein each pixel is divided into divided areas equal in number to said plurality of diffraction gratings, allocating the respective front Symbol plurality of diffraction gratings on a one-to-one to each of the plurality of divided areas,
Wherein depending on the color to be expressed in the pixel in each pixel, said the changing the area ratio of the diffraction grating with respect to divided regions each diffraction grating is allocated to the divided area allocated the respective diffraction grating Forming a color image.   For each of the plurality of diffraction grating masters on which the respective patterns of the plurality of diffraction gratings are formed, the diffraction grating master is superposed on the transfer object on which the color image is to be formed, and the superposed portion is irradiated with energy rays. Then, the pattern is transferred to the transferred body by melting the surface of the transferred body based on the heat, and the pattern corresponds to a divided area assigned to the diffraction grating in the transferred body. The color image forming method according to claim 1, wherein the energy beam is moved so that the diffraction grating is transferred to the divided region, and the diffraction grating is sequentially formed at a position corresponding to the divided region.   The color image forming method according to claim 2, wherein the plurality of divided regions are regions in which the rectangular pixels are equally divided in a vertical direction.   4. The color image forming method according to claim 2, wherein the direction in which the area ratio of the diffraction grating formed in each of the plurality of divided regions changes in accordance with the color to be expressed is the same. 5. . A color to be expressed in one pixel is a color image expressed by a combination of a plurality of diffraction gratings whose spectra observed in a specific direction are different from each other,
The pixel is divided into a plurality of divided regions, and each of the plurality of divided regions is formed with each of the plurality of diffraction gratings. In each of the divided regions, the division of the diffraction grating formed in the divided region is performed. A color image in which an area ratio with respect to a region varies depending on the color to be expressed.

Images