JPH0990860A - Reproduction of hologram array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reproduce exactly the same hologram array from a hologram array original plate, such as hologram color filter. SOLUTION: This method comprises reproducing the hologram array by optically reproducing the hologram array from a hologram array original plate 7 having convergent element holograms 5". A hologram photosensitive material 8 is arranged in parallel with the hologram array original plate 7 within a region where the diffracted light rays 10 from the respective element holograms 5" are converted to divergent light rays from the convergent light rays. The hologram photosensitive material is irradiated with illumination light 9 for reconstruction from the hologram array original plate 7 side to cause the interference of the diffracted light rays 10 from the respective element holograms 5" and the rectilinearly transmitted light rays 11 in the hologram photosensitive material 8, by which the reproduced hologram array of the hologram array original plate 7 is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram array duplication method, and more particularly, to a hologram array duplication method capable of completely duplicating the same hologram array from a hologram array such as a hologram color filter.

[0002]

Holographic arrays can be used, for example, instead of microlens arrays. As one of such hologram arrays, the applicant of the present invention has proposed a Japanese Patent Application No.
No. 12170, etc., proposed a hologram color filter for liquid crystal display devices. The structure is composed of an eccentric Fresnel zone plate-shaped micro hologram array. The hologram color filter will be briefly described below.

A liquid crystal display device using this hologram color filter will be described with reference to the sectional view of FIG. In the figure, a hologram array 5 constituting this hologram color filter is arranged at a distance from the backlight 3 incident side of a liquid crystal display element 6 which is regularly divided into liquid crystal cells 6 '(pixels). On the back of the liquid crystal display element 6,
A black matrix 4 provided between the liquid crystal cells 6'is arranged. In addition to the above, polarizing plates (not shown) are arranged on both sides of the liquid crystal display element 6. It should be noted that an absorption type color filter that transmits light of colors corresponding to R, G, and B color separation pixels is arranged between the black matrix 4 as in the conventional color liquid crystal display device. Is also good.

The hologram array 5 has a repetition period of R, G, and B color separation pixels, that is, a set of three liquid crystal cells 6 ′ adjacent to each other in the direction of the liquid crystal display element 6 in the plane of the paper. The micro holograms 5 'are arranged in an array at the same pitch as the repetition pitch. The micro holograms 5' are aligned with each set of three liquid crystal cells 6 'adjacent to each other in the direction of the plane of the liquid crystal display element 6, and each hologram 5' Each of the micro holograms 5 ′ corresponds to the light of the green component in the backlight 3 that enters at an angle θ with respect to the normal to the hologram array 5 and corresponds to the micro hologram 5 ′. It is formed in a Fresnel zone plate shape so that light is condensed on the liquid crystal cell G at the center of the three color separation pixels R, G, and B. The micro hologram 5 ′ has a relief type, which has no or little wavelength dependence of the diffraction efficiency.
It consists of transmission holograms such as phase type and amplitude type. Here, the fact that there is no or little wavelength dependence of the diffraction efficiency is not a type that diffracts only a specific wavelength and does not diffract other wavelengths like a Lippman hologram,
Means that one diffraction grating diffracts any wavelength,
The diffraction grating having a small wavelength dependence of the diffraction efficiency diffracts at different diffraction angles according to the wavelength.

[0005] With such a configuration, when the white backlight 3 that enters at an angle θ with respect to the normal line from the surface of the hologram array 5 opposite to the liquid crystal display element 6 is incident, the wavelength is reduced. Accordingly, the diffraction angle of the minute hologram 5 'is different, and the light condensing position for each wavelength is dispersed in a direction parallel to the hologram array 5 surface. Among them, the red wavelength component is located at the position of the liquid crystal cell R displaying red, the green component is located at the position of the liquid crystal cell G displaying green, and the blue component is located at the position of the liquid crystal cell B displaying blue. By arranging the hologram array 5 so as to diffract and collect light, each color component passes through each liquid crystal cell 6 ′ with almost no attenuation in the black matrix 4 and the liquid crystal cell 6 ′ at the corresponding position. Color display can be performed according to the state.

As described above, by using the hologram array 5 as a color filter, each wavelength component of the conventional color filter backlight can be made incident to each liquid crystal cell 6'without being absorbed, and its utilization efficiency is improved. Can be significantly improved.

The production of such a color filter composed of a hologram array is performed, for example, by a duplication method using two-beam interference of multipoint convergent light and zero-order transmitted light emitted from a minute hologram lens array composed of a computer hologram (Japanese Patent Application No. Hei 10-26139). 5
-14572). The duplication method will be briefly described with reference to the sectional view of FIG. 4. The hologram interference fringes of the minute hologram 5 ′ are calculated by a computer, and the interference fringes are detected by an electron beam on a glass substrate coated with an electron beam resist, for example. Draw and develop the relief type computer generated hologram (CGH: Computer Gen)
An array 7 of erased Hologram) 5 ″ is produced. Next, as shown in FIG. 4, the hologram sensitive material 8 is formed on the relief surface of the CGH array 7 thus produced.
CG
Laser light 9 is made incident from the H array 7 side at an angle θ corresponding to the backlight 3 of FIG. 3, and each CGH of the CGH array 7 is made incident.
The convergent diffracted light 10 generated by 5 ″ and the linearly transmitted light 11 are caused to interfere in the hologram photosensitive material 8 to duplicate the CGH array 7. This duplicated hologram is used as the hologram array 5 in FIG. The hologram array 5 can also be manufactured by further duplicating a duplicate hologram as an original plate.

[0008]

SUMMARY OF THE INVENTION However, CGH
The hologram array 5 obtained by duplicating the array 7 as a master by the method as shown in FIG. 4 has each minute hologram 5 ′ even if each CGH 5 ″ forming the CGH array 7 has an interference fringe drawn on the entire surface thereof. The interference fringes are not recorded on the entire surface of the holographic material 8, because the hologram sensitive material 8 is usually formed by coating the glass substrate 12 with the photosensitive layer 13 and then laminating the cover film 14 thereon, as shown in FIG. Therefore, even if the CGH array 7 and the hologram photosensitive material 8 are brought into close contact with each other, a gap (about 50 μm) due to the cover film 14 is formed between the relief surface of the CGH array 7 and the photosensitive layer 13 and converges in the photosensitive layer 13. This is because the region N where the diffracted light 10 does not enter is generated.

As described above, in the copying method as shown in FIG. 4, the area in which interference fringes are recorded becomes smaller as the copying is repeated. Further, the focal length of the minute hologram 5'is also shortened. Further, the degree of modulation of the recorded interference fringes also becomes small. The distance (pitch) between the centers of the minute holograms 5'does not change in the duplicating method as shown in FIG.

When the interference fringe recording area of each minute hologram 5'is made smaller than the entire surface by duplication in this way, when the backlight 3 is irradiated, the incident light is diffracted to generate a region N in which wavelength dispersion is not possible, resulting in spectral efficiency. Is decreasing,
Unnecessary zero-order light increases.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a hologram array capable of completely replicating the same hologram array from a hologram array original plate such as a hologram color filter. It is to provide a duplication method.

[0012]

The hologram array duplication method of the present invention that achieves the above object is a method of duplicating a hologram array by optical duplication from a hologram array original plate in which element holograms are convergent. A hologram photosensitive material is placed in parallel with the hologram array master plate in the area where the diffracted light from the hologram is converted from convergent light to divergent light, and the reconstruction illumination light is irradiated from the hologram array master plate side to diffract from each element hologram. A method is characterized in that a duplicate hologram array of the hologram array original plate is obtained by causing light and linearly transmitted light to interfere in a hologram photosensitive material.

In this case, the distance between the hologram array original plate and the photosensitive layer of the hologram photosensitive material can be set to about twice the focal length of the element hologram.

As the hologram array original plate, for example, a computer generated hologram array can be used.

Further, the obtained duplicated hologram array may be used as a hologram array original plate again and duplicated in the same arrangement.

Further, as the duplicate hologram array,
For example, each element hologram can be applied to a hologram color filter having a function of wavelength-dispersing white light incident at an angle with respect to the normal line of the recording surface in the direction along the recording surface and separating the light.

In the present invention, the hologram photosensitive material is arranged in parallel with the hologram array original plate in the area where the diffracted light from each element hologram is converted from the convergent light to the divergent light, and the reproduction illumination light is emitted from the hologram array original plate side. By irradiating, the diffracted light from each element hologram and the linearly transmitted light interfere with each other in the hologram photosensitive material to obtain a duplicate hologram array of the hologram array original plate, so that between the hologram array original plate and the photosensitive layer of the hologram photosensitive material. Because of the distance
By duplicating the same hologram as that of the original plate, it is possible to prevent the generation of a region where hologram interference fringes are not recorded and are not diffracted, or to enlarge or reduce the hologram interference fringe recording region of the original plate. Further, since the hologram array original plate and the hologram photosensitive material can be duplicated while being separated from each other, scratches and the like are less likely to be caused on the hologram array original plate, and abrasion resistance is improved.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The basic principle of the present invention is to reproduce a hologram array original plate 7 in an arrangement as shown in FIG.
In order to prevent the recording area of each element hologram from becoming inevitably small and the area N where hologram interference fringes cannot be recorded from occurring, the photosensitive layer 13 is arranged at a position twice the focal length of the element hologram, and each element hologram is recorded. The converged light diffracted from is converted into divergent light, and the diameter of the cross section is duplicated at the position where it is the same as the diameter of the element hologram, so that the same hologram interference fringes as the hologram array original plate 7 are recorded. It is to be. It should be noted that the hologram array obtained by the duplication may be duplicated in the same manner, and laser light traveling in the opposite direction to the reference light 11 at the time of the first duplication is used as the reproduction illumination light at that time.

This principle will be described with reference to FIG. FIG. 1 is a diagram for explaining an embodiment in which a hologram array 5 that constitutes a hologram color filter is produced from the CGH array original plate 7 by one replication. As in the case of FIG. 4, the original plate of the hologram array 5 forming the hologram color filter is formed as the CGH array 7, and the C
The hologram sensitive material 8 is arranged apart from the CGH array original plate 7 by setting the distance from the relief surface of the GH array original plate 7 to the photosensitive layer 13 to 2f which is twice the focal length f of each CGH 5 ″. Laser light 9 is incident from the 7 side at an angle θ corresponding to the backlight 3 in FIG. 3, and the diffracted light 10 which is diffracted from the converged light to the divergent light 10 and the straight transmitted light 11 are diffracted by each CGH 5 ″ of the CGH array original plate 7. Are reproduced in the photosensitive layer 13 of the hologram photosensitive material 8 by interfering with each other.

In this case, if the diameter of the recording region of each element hologram 5 ″ of the CGH array original plate 7 is D, the diffracted light 10
Is once converged from the relief surface of each CGH 5 ″ to the position P of f, and becomes a divergent light beam of the same diameter D at the position of 2f. Therefore, when the photosensitive layer 13 is arranged at this position to interfere with the straight transmitted light 11. , The diameter of the recording area of the hologram interference fringe is the same D, and the pitch between the duplicated element holograms is also C.
The pitch is the same as that between the element holograms 5 ″ of the GH array original plate 7. Moreover, the hologram array thus duplicated travels from the glass substrate 12 side in the direction opposite to the transmitted light 11 when the hologram array is duplicated. When light in the direction of incidence is incident, the photosensitive layer 1 on which hologram interference fringes are recorded
The diffracted light is condensed at the position P at a distance f from 3 and becomes the same as the focal length of the element hologram 5 ″ of the CGH array original plate 7.
That is, the hologram array which is completely the same as the CGH array original plate 7 is duplicated.

In the arrangement of FIG. 1, since the cover film 14 having a certain thickness is arranged on the incident side of the photosensitive layer 13, the diameter of the recording area of the hologram interference fringes in the photosensitive layer 13 is strictly D. Slightly smaller. Therefore, an area N (FIG. 4) in which no hologram interference fringe corresponding to the difference is recorded is generated. To prevent this, C
The distance from the relief surface of the GH array original plate 7 to the photosensitive layer 13 may be slightly larger than 2f. The duplicated hologram array may be used with the cover film 14 attached or used with the cover film peeled off. However, the two have different focal lengths. It is necessary to set the focal length of CGH5 ″.

Further, in the case of duplication in the arrangement as shown in FIG.
Unwanted reflection occurs on both surfaces of the CGH array original plate 7 and on the surface (rear surface) of the glass substrate 12 opposite to the photosensitive layer 13, and the unnecessary reflected light and the straight transmitted light 11 interfere with each other, and unnecessary interference fringes are simultaneously recorded. There is a risk that To prevent this,
At least one surface of the CGH array original plate 7 may be provided with an antireflection film, and the back surface of the glass substrate 12 may be provided with a light absorption layer.

By the way, the hologram array obtained by duplicating from the CGH array original plate 7 in the arrangement shown in FIG. 1 is not used as the hologram color filter 5 as it is, but this duplicate hologram array is reproduced again as the original plate in the same manner. The obtained hologram array can be used as the hologram color filter 5.
FIG. 2 shows an arrangement for performing such a second replication. In the figure, the hologram array obtained by duplication in the arrangement of FIG. 1 is used as an intermediate hologram array H1, and the intermediate hologram array H1 is used as an original plate to perform duplication again. In this case, the hologram photosensitive material 8 is arranged on the original plate 7 side when the intermediate hologram array H1 is duplicated, and the laser beam 9'for reproduction illumination is on the side opposite to the hologram photosensitive material 8 and the intermediate hologram array H1. Is transmitted in the direction opposite to that of the transmitted light 11 in the case of replicating. Then, from the diffractive surface of the intermediate hologram array H1 to the photosensitive layer 1 of the hologram photosensitive material 8.
The distance to 3 is set to 2f, which is twice the focal length f of the element hologram. With such an arrangement, when the laser light 9 ′ for reproduction illumination is made incident on the intermediate hologram array H1,
The light 10 'diffracted from each element hologram of the intermediate hologram array H1 travels in the opposite direction to the diffracted light 10 in FIG. 1, converges once, and becomes a divergent light flux with the same diameter D at the position 2f. Therefore, as in the case of FIG. 1, in the photosensitive layer 13 arranged at this position, the diffracted light 10 ′ and the straight transmitted light 11 ′ are formed.
Interfere with each other, and an array of element holograms having the same focal length f is duplicated and recorded in the area of the same diameter D at the pitch D.

By the way, in the arrangement shown in FIGS. 1 and 2, the photosensitive layer 1 of the hologram photosensitive material 8 is moved from the diffractive surface of the original plate 7 or H1.
When the distance to 3 is larger than 2f, the hologram interference fringe recording area expands larger than D and the focal length of the element hologram increases, and when the distance is smaller than 2f, the hologram interference fringe recording area shrinks smaller than D. ,
The focal length of the element hologram becomes smaller. In any case, the dimension of the element hologram itself (distance between centers of adjacent element holograms: pitch) does not change.

Therefore, in the duplication method of the present invention, when the distance from the original plate to the photosensitive layer is approximately twice the focal length of the element hologram forming the hologram array, the same hologram as the original plate is duplicated and is not diffracted. In order to prevent the generation of N, if the focal length of the element hologram is approximately twice the focal length, it is necessary to enlarge the hologram interference fringe recording area of the original plate (for example, not to draw the entire area of the element hologram but to draw an area smaller than that area). Then, when hologram interference fringes are recorded in the entire area of the element hologram by duplication), if the focal length of the element hologram is less than approximately twice, the interference fringe spacing is drawn wider than it actually is, and it is reduced by duplication. Available for In particular, in the production of the hologram color filter as described in FIG. 3, in order to prevent the generation of the region N (FIG. 4) in which the incident light is diffracted and the wavelength cannot be dispersed, the duplication method approximately twice as large as the present invention is used. Is suitable. The duplication method of the present invention can also be used to increase or decrease the focal length.

By the way, in controlling the distance between the original plate and the hologram photosensitive material at the time of duplication, the thickness of the spacer for inserting the gap between the hologram original plates 7 and H1 and the hologram photosensitive material 8 between them is adjusted. Can be controlled. In addition, duplication may be performed while measuring the gap between them with a sensor such as a laser focus displacement meter (gap measuring machine), a contact displacement sensor, a non-contact displacement sensor, or an air sensor.

Further, the gap between them is reproduced by controlling the position by using a focal length measuring device such as a microscope or a CCD camera in which the hologram original plate 7, H1 or the hologram sensitive material 8 is provided with an alignment mark in advance. You can also Further, it is also possible to record a hologram having a focal point at an arbitrary distance on the hologram original plate 7, H1 or the hologram sensitive material 8 and use the generated image of the hologram itself to copy while controlling the gap between them. it can.

Further, the hologram master plate 7 to be duplicated has CGH 5 ″ attached on multiple sides, but the hologram original plate 7 is not limited to this and may be an optically recorded hologram array. Although the hologram color filter is assumed as the hologram array, it is needless to say that the duplication method of the present invention can be applied to duplication of hologram arrays, hologram lens arrays, and the like for other purposes.

Although the hologram array duplication method of the present invention has been described above based on the embodiments, the present invention is not limited to these embodiments and various modifications can be made.

[0030]

As is apparent from the above description, according to the hologram array duplication method of the present invention, the hologram array master plate is arranged parallel to the hologram array master plate in the region where the diffracted light from each element hologram is converted from the convergent light to the divergent light. A hologram sensitive material is arranged, and the reproduction illumination light is irradiated from the hologram array original side, and the diffracted light from each element hologram and the linearly transmitted light interfere with each other in the hologram sensitive material to duplicate the hologram array original hologram array. Therefore, due to the distance between the hologram array original plate and the photosensitive layer of the hologram photosensitive material, the same hologram as the original plate is duplicated to prevent the occurrence of a region where there is no recording of hologram interference fringes and no diffraction occurs. The hologram interference fringe recording area can be enlarged or reduced. Further, since the hologram array original plate and the hologram photosensitive material can be duplicated while being separated from each other, scratches and the like are less likely to be caused on the hologram array original plate, and abrasion resistance is improved. The hologram array duplication method of the present invention is particularly suitable for preventing the generation of a region in which wavelengths cannot be dispersed by diffracting incident light when manufacturing a hologram color filter.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of a hologram array duplication method of the present invention.

FIG. 2 is a diagram showing an arrangement for performing duplication again using the duplicate hologram array obtained in the arrangement of FIG. 1 as an original plate.

FIG. 3 is a cross-sectional view of a liquid crystal display device using a hologram color filter.

FIG. 4 is a cross-sectional view for explaining a conventional duplication method.

[Explanation of symbols]

 5 "... CGH 7 ... CGH array original plate 8 ... Holographic material 9 ... Laser light 9 '... Laser light 10 ... Converging diffracted light 10' ... Divergence diffracted light 11 ... Straight transmitted light 13 ... Photosensitive layer H1 ... Intermediate hologram array

Claims (5)

[Claims] 1. A method of duplicating a hologram array by optical duplication from a hologram array original plate in which element holograms are converging, the hologram array being within a region where the diffracted light from each element hologram is converted from convergent light to divergent light. The hologram photosensitive material is arranged in parallel with the original plate, and the reproduction illumination light is irradiated from the hologram array original plate side, and the diffracted light from each element hologram and the linearly transmitted light are caused to interfere with each other in the hologram photosensitive material. A method for duplicating a hologram array, characterized by obtaining a duplicate hologram array of an original plate. 2. The method of replicating a hologram array according to claim 1, wherein the distance between the hologram array original plate and the photosensitive layer of the hologram photosensitive material is set to be approximately twice the focal length of the element hologram. . 3. The hologram array replicating method according to claim 1, wherein the hologram array original plate is a computer generated hologram array. 4. The hologram array duplicating method according to claim 1, wherein the duplicate hologram array thus obtained is again used as a hologram array original plate and duplicated in the same arrangement. 5. The hologram color having a function of wavelength-dispersing white light incident on each element hologram at an angle with respect to a normal line of a recording surface in a direction along the recording surface to disperse the duplicate hologram array. The hologram array duplication method according to claim 1, wherein the hologram array duplication method is a filter.