JP4433357B2 - Hologram master and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hologram master, and more particularly to a hologram master with multiple faces.
[0002]
[Prior art]
In Japanese Patent Application No. 5-12170, the present applicant has proposed a color filter using a hologram in order to greatly improve the utilization efficiency of a backlight for liquid crystal display. This hologram color filter basically consists of an array of transmissive condensing element holograms that diffract parallel light incident at a specific wavelength and at a specific oblique incident angle so as to converge at a specific focal length. It will be.
[0003]
In order to replicate a hologram array having the same characteristics using such a hologram array as an original plate by a hologram duplicating method, for example, a first original plate is produced as a computer generated hologram (CGH), and then the first original plate is produced by a hologram duplicating method. A method is used in which a hologram master is produced by duplication, and the final product is duplicated from the hologram master by the same hologram duplication method.
[0004]
As a method for duplicating the transmission type condensing element hologram array as described above, in the Japanese Patent Application No. 7-249115, the present applicant, when replicating from the first original and the hologram original, We proposed a method of replicating holograms with the same characteristics as the original plate by setting the distance between them to approximately twice the focal length of the element hologram. Hereinafter, this method will be briefly described.
[0005]
FIG. 5 is a view for explaining a method of producing a hologram array constituting the hologram color filter from the CGH array original plate 7 by one copy. The original hologram array constituting the hologram color filter is configured as a CGH array 7, and the distance from the relief surface of the CGH array original plate 7 to the photosensitive layer 13 is set to 2f which is twice the focal length f of each CGH 5 ″. The hologram photosensitive material 8 is disposed away from the CGH array original plate 7. A laser beam 9 having a specific wavelength is incident at a specific incident angle θ from the CGH array original plate 7 side, and is diffracted and converged by each CGH 5 ″ of the CGH array original plate 7. The diffracted light 10 that has been diverged from light and the linearly transmitted light 11 are duplicated by causing interference in the photosensitive layer 13 of the hologram photosensitive material 8.
[0006]
In this case, when the diameter of the recording area of each element hologram 5 ″ of the CGH array original plate 7 is D, the diffracted light 10 once converges from the relief surface of each CGH 5 ″ to the position P of f and has the same diameter D at the position 2f. Becomes the divergent luminous flux. Therefore, when the photosensitive layer 13 is arranged at this position and interferes with the linearly transmitted light 11, the diameter of the recording area of the hologram interference fringe becomes the same D, and the pitch between the copied element holograms is also the same as that of the CGH array original plate 7. The pitch is the same as that between the element holograms 5 ″. Moreover, light traveling in the direction opposite to the transmitted light 11 when replicating the hologram array is incident on the hologram array thus replicated from the glass substrate 12 side. As a result, the diffracted light is collected at a position P at a distance f from the photosensitive layer 13 on which the hologram interference fringes are recorded, and becomes the same as the focal length of the element hologram 5 ″ of the CGH array original plate 7. That is, the same hologram array as the CGH array original plate 7 is duplicated.
[0007]
A hologram array obtained by duplicating from the CGH array master 7 in the arrangement as shown in FIG. 5 is similarly duplicated as a hologram master to obtain a final product. FIG. 6 shows an arrangement for performing such second replication. In the figure, the hologram array obtained by duplication in the arrangement of FIG. 5 is used as the intermediate hologram array H1, and the intermediate hologram array H1 is used as the original plate, and the duplication is performed again. In this case, the hologram sensitive material 8 is arranged on the original plate 7 side when the intermediate hologram array H1 is duplicated, and the laser light 9 ′ for reproduction illumination is on the opposite side of the hologram sensitive material 8 on the intermediate hologram array H1. Is made to enter in the direction of traveling in the opposite direction to the transmitted light 11 in the case of copying. Then, the distance from the diffraction surface of the intermediate hologram array H1 to the photosensitive layer 13 of the hologram photosensitive material 8 is set to 2f, which is twice the focal length f of the element hologram. In this arrangement, when the reproduction illumination laser light 9 ′ is incident on the intermediate hologram array H1, the light 10 ′ diffracted from each element hologram of the intermediate hologram array H1 is opposite to the diffracted light 10 in FIG. Then, once converged, it becomes a divergent light beam having the same diameter D at the position 2f. Accordingly, similarly to the case of FIG. 5, the diffracted light 10 ′ and the linearly transmitted light 11 ′ interfere with each other in the photosensitive layer 13 disposed at this position, and the same focal length f is applied to the region having the same diameter D at the pitch D. An array of element holograms is duplicated and recorded.
[0008]
According to this method, a hologram having the same characteristics as the original plate can be produced without completely adhering the original plate and the duplicate. Hereinafter, the hologram replication method with the above arrangement will be referred to as a double focus replication method.
[0009]
By the way, a hologram (intermediate hologram array H1) used for duplicating the final product is called a hologram master in the present invention. As such a hologram master, for example, in the case of the hologram color filter described above, 1 corresponds to one screen. If a hologram master having only one hologram (hologram color filter) is prepared and duplicated, the efficiency of duplication is not good.
[0010]
Therefore, conventionally, for example, four or eight holograms are exposed by replicating a plurality of times while moving the CGH master plate 7 in parallel with one large hologram sensitive material 8 to expose four or eight holograms. There is a method in which a hologram original plate on which holograms are arranged is prepared and the number of holograms is simultaneously replicated by one replication. Thus, a hologram master in which a plurality of holograms are arranged in parallel in one hologram master is called a multi-sided hologram master.
[0011]
[Problems to be solved by the invention]
In such a multi-sided hologram master, it is conceivable to arrange a common cover glass to protect each hologram, but an ND (light absorption) film or hard coat is provided on the cover glass for the purpose of preventing interface reflection or the like. It is necessary to provide. However, when these films are applied by spin coating or the like, a bulge of the coating film is formed around the cover glass, and the bulge hinders hologram duplication, making accurate and efficient duplication difficult. There is a case.
[0012]
In addition, when a hologram is replicated in close contact with a replication hologram sensitive material, the corners of the edge around the cover glass may damage the hologram sensitive material.
[0013]
Furthermore, there is a possibility that the refractive index matching liquid such as xylene swells the adhesive used for bonding the cover glass to deteriorate the durability of the hologram master.
[0014]
The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a multi-sided hologram original plate that can be efficiently and accurately duplicated and is excellent in durability.
[0015]
[Means for Solving the Problems]
The hologram master of the present invention that achieves the above object is a hologram master in which a plurality of unit hologram masters are provided in parallel on a substrate.
The surface of the plurality of unit hologram masters arranged in parallel is covered with a common transparent thin plate via an adhesive, and a bend toward the substrate side is formed around the transparent thin plate. Is.
[0016]
In this case, an elongate flat plate having a thickness slightly smaller than the thickness of the unit hologram original plate is arranged around the plurality of unit hologram original plates arranged in parallel on the substrate, and the transparent thin plate extends over the flat plate and is bonded by an adhesive. It is desirable that a bend is formed in the elongated flat plate portion.
[0017]
As the adhesive, for example, a curing shrinkable adhesive such as an ultraviolet curable adhesive, a thermosetting adhesive, or a two-component curable adhesive can be used.
[0018]
Moreover, it is desirable that the corners of the edges around the transparent thin plate are chamfered.
[0019]
Furthermore, a protective film is desirably formed on the adhesive exposed surface between the periphery of the transparent thin plate and the substrate, and the protective film is desirably a protective film against the refractive index matching liquid.
[0020]
In the present invention, in a hologram master in which a plurality of unit hologram masters are provided in parallel on a substrate, the surfaces of the plurality of unit hologram masters arranged in parallel are covered with a single transparent thin plate via an adhesive. Since the bend toward the substrate side is formed around the transparent thin plate, the coating film provided on the surface of the transparent thin plate is prevented from rising to the periphery and forming a raised portion, and hologram close-contact replication In this case, any multi-faceted hologram can be accurately and efficiently duplicated. In addition, when the hologram photosensitive material is made in close contact with the multi-sided hologram master via a refractive index matching liquid, the refractive index matching liquid does not dissolve the optical adhesive between the unit hologram masters. Absent.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the hologram master according to the present invention will be described below based on the production method.
[0022]
1 to 4 sequentially show sectional views of steps for carrying out a method for producing a hologram master according to one embodiment of the present invention.
[0023]
First, for example, as shown in FIG. 5, the CGH original plate (first original plate) 7 is duplicated to obtain one hologram by one copy, and a plurality of copies are made. For this purpose, a photosensitive material layer such as a photopolymer is provided on a substrate glass having a dimension corresponding to the size of the hologram and a protective layer is provided thereon, and a hologram photosensitive material is prepared on the CGH array original plate 7. If the hologram sensitive material is placed in close contact with each other or spaced twice the focal length f as shown in FIG. 5 and the CGH original plate 7 is a transmission type, the CGH original plate 7 is reflected from the CGH original plate 7 side. In the case of a mold, duplicate illumination light (corresponding to the laser light 9 in FIG. 5) is incident from the hologram sensitive material side, and in the photosensitive material layer, when the CGH original plate 7 is a transmission type, transmitted light and diffracted light are When the CGH master plate 7 is a reflection type, the CGH master plate 7 is duplicated by making the incident light and the diffracted light interfere with each other, and a plurality of unit hologram masters 20 having the same characteristics are produced.
[0024]
Next, as shown in FIG. 1, a thin glass plate 21 serving as a cover glass having a large area is vacuum-contacted on the optical flat surface of the reference glass 30 having an optical flat surface. When the double focal point replication method is applied, the thickness of the thin glass 21 is preferably selected to be equal to or less than the focal length f. The unit hologram original plate 20 is aligned on the thin glass plate 21 that is in close contact with the vacuum by using an optical adhesive 22 and is pasted so as to have the same height with the same force.
[0025]
Then, an elongated glass plate 23 having a thickness slightly smaller than the thickness of the unit hologram original plate 20 is pasted on the thin glass plate 21 around the aligned unit hologram original plate 20 in the same manner as the unit hologram original plate 20 (thickness is glass). The thickness of the plate 23 is reduced by about 50 μm, for example).
[0026]
Then, the base glass 24 is brought close to the back side of the unit hologram original plate 20 in which the long and thin glass plates 23 are arranged and arranged around it, and reinforced by using, for example, a UV (ultraviolet) curable optical adhesive 25 as shown in FIG. Therefore, the base glass 24 is bonded to prevent the solvent (refractive index matching liquid) from entering the gap between the unit hologram masters 20. When the optical adhesive 25 is a UV curable type, for example, the ultraviolet light 31 is irradiated from the reference glass 30 side or the base glass 24 side to be cured.
[0027]
After the optical adhesive 25 is sufficiently cured, the adsorption between the reference glass 30 and the thin glass 21 that are in vacuum contact is released, and the reference glass 30 and the thin glass (cover glass) 21 are peeled off. A cross-section as shown in FIG. Here, the cover glass 21 originally has a flat exposed surface, but as described above, the thickness of the elongated glass plate 23 arranged around the aligned unit hologram master 20 is the unit hologram. Since the thickness is selected to be slightly smaller than the thickness of the original plate 20, an elongated glass plate 23 is formed at the stage of bonding the base glass 24 in FIG. 2 from the thickness of the optical adhesive 25 interposed between the unit hologram original plate 20 and the base glass 24. The thickness of the optical adhesive 25 interposed between the base glass 24 and the base glass 24 becomes thicker. Therefore, when the optical adhesive 25 is cured, the contraction amount of the layer of the optical adhesive 25 is at the position of the elongated glass plate 23. Is bigger. Therefore, when the suction of the reference glass 30 is released as shown in FIG. 3, the surrounding cover glass 21 corresponding to the position of the elongated glass plate 23 is slightly bent toward the base glass 24, and the cover glass 21 is slightly bent 26 around it. Is formed. The bend 26 toward the base glass 24 of the cover glass 21 is formed around the surface of the cover glass 21 when a thin film such as an ND film or a hard coat is applied to the surface of the cover glass 21 by spin coating or the like as described later. It plays an important role in preventing the bulge of the coating film from being formed.
[0028]
Next, as shown in FIG. 4A, the corners of the edge of the cover glass 21 are chamfered 27 with a tool such as a grinder, and at the same time, the cover glass 21 flows around the cover glass 21 on the base glass 24 and hardens. The optical adhesive 25 being removed is also removed with a similar tool to perform chamfering 28. The chamfer 27 around the cover glass 21 is an edge around the cover glass 21 when the hologram master 50 of the present invention (FIG. 4B) is in close contact with the hologram sensitive material for duplication to reproduce the hologram. This is to prevent the corners from damaging the hologram photosensitive material.
[0029]
Next, as shown in FIG. 4 (b), the surface of the optical adhesive 25 on the surface of the cover glass 21 and the peripheral surface of the cover glass 21 are not affected by the refractive index matching liquid such as xylene. A protective film 29 is applied. For example, PVA (polyvinyl alcohol) is used as the protective film 29. The protective film 29 functions because the refractive index matching liquid such as xylene interposed between the hologram master 50 of the present invention in close contact with the hologram photosensitive material for duplication and the hologram duplication causes the optical adhesive 25 to swell. This is to prevent the hologram original plate 50 from being deteriorated in durability.
[0030]
Finally, an ND for preventing interfacial reflection or attenuating unnecessary order light on the surface of the cover glass 21 in which a bend 26 is formed in the periphery and the corners of the peripheral edges are chamfered 27. The hologram master 50 of the present invention is completed by applying the (light absorption) film and the hard coat film 40 by spin coating or the like. At this time, since the bend 26 is formed around the cover glass 21, it is possible to prevent the coating film 40 from being raised around the cover glass 21 of the hologram original plate 50 and forming a bulge portion. Will not hinder.
[0031]
The hologram master according to the present invention has been described above based on the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made. For example, any optical adhesive 25 may be used as long as it shrinks when cured, such as a thermosetting type or a two-component curing type, instead of a UV curing type. The hologram to be duplicated may be a transmission type or a reflection type, and the multi-sided hologram original plate 50 does not necessarily have to be duplicated by the contact duplication method, and may be duplicated by a double focus duplication method.
[0032]
【The invention's effect】
As is apparent from the above description, according to the hologram master of the present invention, in the hologram master in which a plurality of unit hologram masters are provided in parallel on the substrate, the surface of the plurality of unit hologram masters arranged in parallel is an adhesive. Is covered with a single transparent thin plate, and a bend toward the substrate is formed around the transparent thin plate, so that the coating film provided on the surface of the transparent thin plate rises to the periphery and rises Is prevented, and does not hinder the hologram close-contact replication, and any multi-faceted hologram can be accurately and efficiently replicated. In addition, when the hologram photosensitive material is made in close contact with the multi-sided hologram master via a refractive index matching liquid, the refractive index matching liquid does not dissolve the optical adhesive between the unit hologram masters. Absent.
[Brief description of the drawings]
FIG. 1 is a sectional view of a first step of a method for producing a hologram master according to an embodiment of the present invention.
FIG. 2 is a sectional view of a step following FIG. 1;
FIG. 3 is a sectional view of a step following FIG. 2;
4 is a cross-sectional view of a process following FIG. 3 and a cross-sectional view of a hologram master according to one embodiment of the present invention.
FIG. 5 is a diagram showing an arrangement for performing hologram replication from a CGH array original plate by a conventional double focus replication method.
6 is a diagram showing an arrangement for performing replication again using the duplicate hologram obtained in the arrangement of FIG. 5 as an original plate.
[Explanation of symbols]
5 "... CGH
7 ... CGH original edition (first original edition)
DESCRIPTION OF SYMBOLS 8 ... Hologram sensitive material 9 ... Laser beam 9 '... Laser beam 10 ... Convergent diffracted beam 10' ... Divergence diffracted beam 11 ... Straight transmission light 11 '... Straight transmission light 12 ... Glass substrate 13 ... Photosensitive layer 20 ... Unit hologram original plate 21 ... Cover glass (thin glass)
22 ... Optical adhesive 23 ... Elongated glass plate 24 ... Base glass 25 ... Optical adhesive (ultraviolet curing type)
26 ... Bending 27 ... Chamfering 28 ... Chamfering 29 ... Protective film 30 ... Reference glass 31 ... Ultraviolet light 40 ... ND film, hard coat (coating film)
50 ... Hologram master

Claims (6)

In the hologram master in which a plurality of unit hologram masters are provided in parallel on the substrate,
The surface of the plurality of unit hologram masters arranged in parallel is covered with a common transparent thin plate via an adhesive, and a bend toward the substrate side is formed around the transparent thin plate. Hologram original. An elongated flat plate having a thickness slightly smaller than the thickness of the unit hologram original plate is disposed around the plurality of unit hologram original plates arranged in parallel on the substrate, and the transparent thin plate extends over the flat plate and is bonded by the adhesive. 2. The hologram master according to claim 1, wherein the bent portion is formed in the elongated flat plate portion. 3. The hologram original plate according to claim 2, wherein the adhesive is a curing shrinkable adhesive such as an ultraviolet curable adhesive, a thermosetting adhesive, or a two-component curable adhesive. 4. The hologram original plate according to claim 1, wherein corners of edges around the transparent thin plate are chamfered. The hologram master according to any one of claims 1 to 4, wherein a protective film is formed on the adhesive exposed surface between the periphery of the transparent thin plate and the substrate. 6. The hologram original plate according to claim 5, wherein the protective film is a protective film against a refractive index matching liquid.

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