Hologram manufacturing method, light guide plate, and hologram master

Abstract

To improve the production efficiency of a hologram by easily filling a refractive index matching liquid.SOLUTION: In the method for manufacturing the hologram, a superposing member 3 is arranged on one side of a material 1 to be treated having an unexposed photosensitive layer 11 with a gap S, refractive index matching liquid is filled in the gap S between the material 1 to be treated and the superposing member 3, and coherent light is irradiated on the photosensitive layer 11 after filling the refractive index matching liquid to record an interference fringe on the photosensitive layer 11.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for producing a hologram. [Background technology]

[0002] A hologram can be produced by irradiating a photosensitive layer with laser light of a predetermined wavelength from two different directions. Another known method for producing a hologram is to use a hologram master plate having a master hologram and optically replicate the interference fringes of the master hologram onto a photosensitive layer (Patent Document 1). Patent Document 1 discloses a method of replicating a hologram by laminating a photosensitive material film 1 for duplication onto a hologram master 35, dripping a refractive index matching liquid onto the film 1, and then covering the film with anti-reflection coated glass 34, and then irradiating laser light 47 onto the master 35 from the film 1 side. The symbols in the Background Art section are those used in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-162951 Summary of the Invention

[0004] In Patent Document 1, it takes time for the dropped refractive index matching liquid to spread into a thin film on the photosensitive film 1 due to capillary force. Even if a large amount of refractive index matching liquid is dropped, the capillary force does not improve, and the time required for the liquid to spread into a thin film is hardly shortened. Furthermore, if the refractive index matching liquid is dropped onto the photosensitive film 1 for manufacturing and then covered with anti-reflection coated glass 34, there is a risk of air bubbles being trapped if the refractive index matching liquid does not spread into a thin film on the film 1. For this reason, it is desirable to fill the gap between the film 1 and the anti-reflection coated glass 34 (corresponding to the overlapping member) with a refractive index matching liquid after overlapping the film 1 (corresponding to the material to be treated). However, Patent Document 1 does not disclose or suggest such a method at all. If the gap could be easily filled with a refractive index matching liquid, the work time could be shortened and the production efficiency of holograms could be improved. [Problem to be solved by the invention]

[0005] A first object of the present invention is to provide a method for manufacturing a hologram that allows for easy filling of a refractive index matching liquid and improves the production efficiency of holograms. A second object of the present invention is to provide a hologram master for hologram duplication that can be easily filled with a refractive index matching liquid. [Means for solving the problem]

[0006] In one aspect, a method for producing a hologram is provided. The first form of the method for manufacturing a hologram includes an arrangement step of arranging an overlapping member with a gap on one side of a processed material having an unexposed photosensitive layer, a filling step of filling the gap between the processed material and the overlapping member with a refractive index matching liquid, and an exposure step of recording interference fringes in the photosensitive layer by irradiating the photosensitive layer with coherent light after filling the refractive index matching liquid, wherein the overlapping member has a supply hole that leads to the gap, and the refractive index matching liquid is filled into the gap from the supply hole.

[0007] The second type of hologram manufacturing method is the same as the first type of manufacturing method, except that the supply hole is formed in an area of ​​the overlapping member through which coherent light for recording interference fringes in the photosensitive layer does not propagate. A third embodiment of the hologram manufacturing method is the same as the first or second embodiment, wherein the diameter of the supply hole is 0.5 mm to 10 mm. A fourth embodiment of the hologram manufacturing method is the same as any one of the first to third embodiments, in which a plurality of the supply holes are formed at intervals. A fifth embodiment of the hologram manufacturing method is the fourth embodiment of the hologram manufacturing method, wherein the interval between the adjacent supply holes is 20 mm to 150 mm. The sixth embodiment of the hologram manufacturing method is the same as any one of the first to fifth embodiments, except that the processed material has a supporting substrate and the photosensitive layer provided on the supporting substrate, and in the placement step, the overlapping member is placed on one side of the supporting substrate of the processed material with the gap therebetween. A seventh aspect of the hologram manufacturing method is the manufacturing method of any one of the first to sixth aspects, wherein the overlapping member is a hologram master plate having a master hologram. The hologram manufacturing method of the eighth aspect is the manufacturing method of any one of the first to sixth aspects, wherein the overlapping member is a light-transmitting plate. A hologram manufacturing method of a ninth aspect is the manufacturing method of any one of the first to sixth aspects, wherein the overlapping member is a prism.

[0008] In another aspect, a hologram master is provided. A tenth embodiment of the hologram master plate is used for replicating a hologram. The hologram master plate has an area where a master hologram is formed and an area where the master hologram is not formed, and a supply hole for supplying a refractive index matching liquid is formed in the area where the master hologram is not formed, penetrating the area in the thickness direction. [Effects of the Invention]

[0009] The hologram manufacturing method of the present invention utilizes a supply hole to easily fill the gap between the overlapping member and the processed material with refractive index matching liquid. By simplifying the refractive index matching liquid filling process, the work time can be shortened and hologram production efficiency can be improved. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a schematic side view of a hologram manufacturing apparatus according to a first embodiment. [Figure 2] FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG. 2. [Figure 4] Plan view of the hologram master. [Figure 5] Cross-sectional view taken along line VV in Figure 4. [Figure 6] Cross-sectional view taken along line VI-VI in Figure 4. [Figure 7] FIG. [Figure 8] 3 is a schematic side view showing a step of bringing the photosensitive layer of the processing target material and the light-transmitting plate into close contact with each other in the hologram manufacturing method of the first embodiment. FIG. [Figure 9] FIG. 4 is a cross-sectional view showing a filling step of filling a gap with a refractive index matching liquid in the first embodiment. [Figure 10] FIG. 1 is a reference explanatory diagram showing an exposure process in which interference fringes are formed on a photosensitive layer by coherent light. [Figure 11] FIG. 10 is a schematic side view showing a step of wiping off the refractive index matching liquid. [Figure 12] Plan view of the hologram continuum. [Figure 13] FIG. 10 is a reference side view of a light guide plate on which red, green, and blue holograms are stacked. [Figure 14] FIG. 10 is a schematic side view of a hologram manufacturing apparatus according to a second embodiment. [Figure 15] FIG. [Figure 16] FIG. 16 is an enlarged cross-sectional view taken along line XVI-XVI in FIG. [Figure 17] FIG. 10 is a schematic side view of a hologram manufacturing apparatus according to a third embodiment. [Figure 18] FIG. [Figure 19] 19 is an enlarged cross-sectional view taken along line XIX-XI in FIG. 18. [Figure 20] FIG. 11 is a cross-sectional view showing a filling step of filling a gap with a refractive index matching liquid in the third embodiment. [Figure 21]FIG. 1 is a reference explanatory diagram showing an exposure process in which interference fringes are formed on a photosensitive layer by coherent light. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] One embodiment will be described below with reference to the drawings. In this specification, the "first surface" of a certain component (e.g., a hologram master or a light-transmitting plate) refers to the surface on which coherent light is incident to expose a photosensitive layer, and the "second surface" of a certain component refers to the surface opposite to the first surface. It should be noted that the thickness, size, scale, and shape of elements such as layers shown in each drawing may differ from the actual ones.

[0012] {Hologram manufacturing apparatus according to the first embodiment} The first embodiment relates to a manufacturing apparatus that uses a hologram master to record interference fringes of a master hologram on a photosensitive layer, that is, that replicates a hologram on a photosensitive layer. Fig. 1 is a side view of a hologram manufacturing apparatus according to a first embodiment, Fig. 2 is a plan view of an exposure unit in the manufacturing apparatus as seen from above, and Fig. 3 is an enlarged cross-sectional view of the exposure unit taken along the conveyance direction. Note that a refractive index matching liquid supply device is omitted from Fig. 2. In this specification, the "conveying direction" corresponds to the longitudinal direction of the material to be treated, and the "width direction" refers to the direction perpendicular to the longitudinal direction within the surface of the material to be treated.

[0013] The hologram manufacturing apparatus of this embodiment exposes a photosensitive layer to coherent light and diffracted light generated from a master hologram by irradiation with the coherent light, thereby recording interference fringes of the master hologram in the photosensitive layer and replicating a hologram in the photosensitive layer. In this specification, a hologram replicated using a hologram master may be referred to as a "replica hologram." The material to be processed having a photosensitive layer may be in the form of a sheet, but is preferably in the form of a long strip. By loading the material to be processed having a photosensitive layer into the manufacturing device and exposing the photosensitive layer using the manufacturing device, multiple replicate holograms can be continuously obtained. The sheet shape refers to a predetermined size, such as a substantially rectangular, square, or circular shape in plan view. The long strip shape is a strip whose longitudinal length is sufficiently longer than its lateral length. A long strip photosensitive layer is usually stored wound up in a roll and unwound from the roll when in use. A manufacturing apparatus for producing a replica hologram on a long strip-shaped photosensitive layer will now be described in detail.

[0014] 1 to 3, the manufacturing apparatus A has a conveying section B that conveys the workpiece 1 having the photosensitive layer 11 in the longitudinal direction, an exposure section C that exposes the photosensitive layer 11 conveyed by the conveying section B, and a light source D that irradiates the laminate including the photosensitive layer 11 with coherent light L1 in the exposure section C. Various operations of the manufacturing apparatus A, which will be described later, are controlled by a control section (not shown) that includes a computer or the like. The general flow for producing a duplicate hologram is as follows: a workpiece 1 having a photosensitive layer 11 is transported to the exposure section C, a refractive index matching liquid is filled into the gap between the hologram master 3 (which is the overlapping member) and the workpiece 1, the photosensitive layer 11 is exposed to light to form a duplicate hologram, and the workpiece 1 is transported again, and this process is repeated to continuously produce multiple duplicate holograms. In this embodiment, the hologram master 3 corresponds to the overlapping member.

[0015] <Material to be processed having a photosensitive layer> The material to be processed 1 has a photosensitive layer 11. The photosensitive layer 11 is made of an unexposed photosensitive material. Examples of photosensitive materials that can be used include photopolymers, photoresists, silver halide emulsions, and dichromated gelatin. The thickness of the photosensitive layer 11 is typically several μm to 20 μm. The material to be processed 1 may be composed of only the photosensitive layer 11, but the photosensitive layer 11 itself often does not have enough strength to withstand transportation through the manufacturing equipment A. For this reason, the photosensitive layer 11 is typically formed on a long, strip-shaped support substrate 12. Therefore, a preferred material to be processed 1 has the support substrate 12 and the photosensitive layer 11 formed thereon in a solid state. The support substrate 12 is not particularly limited as long as it has a refractive index approximately equal to that of the light-transmitting plate; for example, glass, TAC (triacetyl cellulose), polycarbonate, or other resins are used. The thickness of the support substrate 12 is not particularly limited, and is about 10 μm to 100 μm.

[0016] The long strip-shaped material to be treated 1 may be wound into a roll for storage, transportation, etc. However, it is preferable to attach a protective film 15 or the like to the material to be treated 1 to prevent scratches on the support substrate 12 and photosensitive layer 11. For example, a protective film 15 with an adhesive is attached to the support substrate 12 side of the material to be treated 1. In addition, a release liner 16 is attached to the photosensitive layer 11 side of the material to be treated 1. The release liner 16 is attached for two purposes. One is to protect the photosensitive layer 11. The other is to conceal the slight adhesiveness of the photosensitive layer 11, which has slight adhesiveness, and prevent blocking when the material is wound into a roll. In this way, the laminated film consisting of adhesive-attached protective film 15 / processing target 1 (support substrate 12+photosensitive layer 11) / release liner 16 is wound onto a roll and loaded into the unwinding section of manufacturing device A.

[0017] <Transportation section> The conveying section B unwinds the laminated film including the material 1 to be treated that is wound around a roll, and conveys the unwound laminated film including the material 1 to be treated in its longitudinal direction. Specifically, conveying section B has an unwinding section 21 that loads the laminated film wound around a roll, a film peeling section 22 that peels the protective film 15 together with the adhesive from the laminated film and takes it up, a liner peeling section 23 that peels the release liner 16 from the laminated film and takes it up, accumulation mechanisms 241, 242 that allow the intermittently conveyed material 1 to accumulate and enable continuous unwinding and take-up of the material 1, a film laminating section 25 that bonds another protective film 15 with adhesive to the exposed material 1, a liner laminating section 26 that bonds another release liner 16 to the exposed material 1, and a take-up section 27 that winds up the material 1 to which the protective film 15 and release liner 16 have been bonded. Note that guide rolls and the like are arranged at appropriate positions on the conveying path of conveying section B. In the illustrated example, a first accumulation mechanism 241 is provided between the unwinding section 21 and the exposure section C, and a second accumulation mechanism 242 is provided between the exposure section C and the winding section 27.

[0018] Conveying section B unwinds the laminated film containing the material 1 from unwinding section 21 at a predetermined speed and conveys it longitudinally. Upstream of first accumulation mechanism 241, film peeling section 22 and liner peeling section 23 peel the adhesive-backed protective film 15 and release liner 16 from the laminated film. Conveying section B conveys the material 1 revealed by peeling off the protective film 15 and release liner 16 to exposure section C, where it temporarily stops conveying. As described below, after the exposure process for material 1 is completed in exposure section C, conveying section B conveys material 1 a predetermined length downstream in the conveying direction and then stops again. By repeating this intermittent conveying process—conveying material 1, stopping conveying, exposing, and then conveying material 1 again—multiple replica holograms can be continuously produced in the long strip-shaped photosensitive layer 11.

[0019] After the exposure process is completed, another adhesive-backed protective film 15 and release liner 16 are bonded to the material to be treated 1 in a film bonding section 25 and a liner bonding section 26. A winding section 27 winds up the material to be treated 1 to which the protective film 15 and release liner 16 have been bonded at a predetermined speed. The first accumulation mechanism 241 temporarily stores the material 1 to be treated that is being unwound from the unwinding section 21 while the transport of the material 1 to be treated is stopped at the exposure section C, and on the other hand, when the material 1 to be treated that was stopped at the exposure section C starts to be transported again, it releases the stored material 1 to be treated. The second accumulation mechanism 242 releases the material 1 to be treated that is being wound up on the winding section 27 while the transport of the material to be treated 1 to be treated is stopped at the exposure section C, and on the other hand, it temporarily stores the material 1 to be treated that was stopped at the exposure section C when it starts to be transported again. In the example of FIG. 1, the first accumulation mechanism 241 and the second accumulation mechanism 242 are accumulation rolls that move up and down. It is also possible to configure a production line in which either the first accumulation mechanism 241 or the second accumulation mechanism 242 is not provided.

[0020] <Light source> In the exposure section C, the light source D irradiates the laminate including the photosensitive layer 11 with coherent light L1. Laser light is typically used as the coherent light. There are no particular limitations on the wavelength of the laser light, but when the replicated hologram is incorporated into, for example, an AR (Augmented Reality) device, it is preferable to use laser light in the visible light region. For example, it is preferable to use laser light with a red wavelength, green wavelength, or blue wavelength. In the present invention, "red wavelength" refers to, for example, a wavelength of 600 to 700 nm, "green wavelength" refers to, for example, a wavelength of 500 to 560 nm, and "blue wavelength" refers to, for example, a wavelength of 430 to 500 nm. The type of laser light is not particularly limited, and examples include solid-state lasers, liquid lasers, gas lasers, and semiconductor lasers.

[0021] The light source D includes, for example, a laser oscillator 61, a mirror 64 that changes the direction of laser light emitted from the laser oscillator 61 and directs the laser light toward a laminate including the photosensitive layer 11, and various optical devices (such as a magnifying lens 62 and a collimating lens 63) disposed between the laser oscillator 61 and the mirror 64. The optical devices may be conventionally known and disposed as appropriate. Examples of optical devices include a shutter, a beam expander, a half-wave plate, a dielectric multilayer mirror, and a beam splitter. These optical devices may be appropriately selected and disposed on the optical path. The laser oscillator 61 emits laser light of a predetermined wavelength. In one embodiment, a laser oscillator 61 that emits laser light of a visible light wavelength is used. Examples of such laser oscillators 61 include a red laser oscillator that emits laser light of a red wavelength (referred to as red laser light), a green laser oscillator that emits laser light of a green wavelength (referred to as green laser light), and a blue laser oscillator that emits laser light of a blue wavelength (referred to as blue laser light). For example, a 640 nm laser oscillator manufactured by Cobolt (product name "Cobolt 05-01 Series Bolero") can be used as the red laser oscillator. A 532 nm laser oscillator manufactured by Cobolt (product name "Cobolt 05-01 Series Samba") can be used as the green laser oscillator. A 460 nm laser oscillator manufactured by Coherent (product name "Genesis MX460") can be used as the blue laser oscillator.

[0022] As will be described later, hologram master plate 3 is provided with multiple rows and multiple columns of master holograms. Light source D may be configured to irradiate all of the master holograms with laser light (coherent light) using a single mirror. Alternatively, light source D may be configured to irradiate one master hologram with laser light using a single mirror, and then move the mirror to sequentially irradiate the remaining master holograms with laser light. Alternatively, light source D may have multiple mirrors, and be configured to irradiate several master holograms simultaneously or sequentially with laser light using the multiple mirrors, and then move the multiple mirrors to irradiate the remaining several master holograms simultaneously or sequentially with laser light. In the example shown in FIG. 1, a plurality of mirrors 64 are arranged side by side in the width direction, and the plurality of mirrors 64 can move in the longitudinal direction of the material 1 to be processed either independently or simultaneously.

[0023] <Exposure section> The exposure section C is one part of the manufacturing apparatus A where the photosensitive layer 11 is exposed to light. The exposure section C has a hologram master 3 including a master hologram 31, a master mounting member 38 for mounting the hologram master 3, a light-transmitting plate 41 arranged on the first surface side of the hologram master 3, and a plate mounting member 48 for mounting the light-transmitting plate 41. A material to be processed 1 including a photosensitive layer 11 is interposed between the first surface of the hologram master 3 and the second surface of the light-transmitting plate 41. Therefore, in the exposure section C, the light-transmitting plate 41, the material to be processed 1, and the hologram master 3 are arranged in this order from the bottom up.

[0024] (Hologram master and master mounting member) Fig. 4 is a plan view of hologram master 3 as viewed from the second surface side. Fig. 5 is a cross-sectional view of hologram master 3 including the area where supply holes are provided, and Fig. 6 is a cross-sectional view of hologram master 3 including master hologram 31. Fig. 7 is a perspective view of hologram master 3.

[0025] 1 to 7, the hologram master 3 has at least one master hologram 31, and preferably has multiple master holograms 31. In terms of layer configuration, the hologram master 3 has, for example, a first substrate 32, a second substrate 33, and multiple master holograms 31 interposed between the first substrate 32 and the second substrate 33. The multiple master holograms 31 are arranged at predetermined intervals, preferably at equal intervals, along the surface of the hologram master 3. In the illustrated example, a total of nine master holograms 31 (3 × 3) are provided on the hologram master 3. Specifically, the master holograms 31 are arranged in three rows in the transport direction of the material 1 to be processed and three columns in the width direction of the material 1 to be processed, with intervals between each row and each column. Note that a "row" refers to a group arranged in the width direction, and a "column" refers to a group arranged in the transport direction (corresponding to the longitudinal direction of the material 1 to be processed). However, the number and arrangement of the master holograms 31 provided on the hologram master 3 are not limited to the 3 rows x 3 columns, and can be changed as appropriate.

[0026] The master hologram 31 is a portion in which interference fringes are recorded in a layer 34 (photosensitive material layer) made of a photosensitive material. The thickness of the photosensitive material layer 34 including the master hologram 31 is about several μm to 20 μm. The first and second substrates 32 and 33 are not particularly limited as long as they are base materials having a refractive index substantially equal to that of the light-transmitting plate, and may be made of, for example, glass, TAC (triacetyl cellulose), polycarbonate, or other resins. The thickness of the first and second substrates 32 and 33 is not particularly limited and is about 10 μm to 100 μm.

[0027] The hologram master 3 is produced, for example, by the following method. First and second substrates 32 and 33 are provided on both sides of a photosensitive material layer 34, such as a photopolymer. Next, a master hologram is created by irradiating the photosensitive material layer 34 with light of a predetermined wavelength from two different directions: a direction forming an angle α with respect to the XY plane (hereinafter referred to as the "α direction") and a direction forming an angle β with respect to the XY plane (hereinafter referred to as the "β direction"). Specifically, by irradiating the photosensitive material layer 34 with interference light of laser light of a predetermined wavelength from two directions, the monomer component in the irradiated portion of the photosensitive material layer 34 is diffused, resulting in a refractive index distribution. This records interference fringes in the irradiated portion, forming the master hologram 31. A bleaching process is then performed to complete the photoreaction in the unexposed portion of the photosensitive material layer 34 (the portion where the master hologram is not formed). When red laser light is irradiated, a red master hologram is generated, when green laser light is irradiated, a green master hologram is generated, and when blue laser light is irradiated, a blue master hologram is generated.

[0028] The hologram master 3, which is a stacking member, may be used as is. To prevent deformation such as curvature when the hologram master 3 is moved, the hologram master 3 is attached to a master mounting member 38. The master mounting member 38 has a portion 381 that holds the hologram master 3 and a movement mechanism 382 that moves the holding portion 381. The holding portion 381 is attached in close contact with the periphery and second surface of the hologram master 3. The movement mechanism 382 moves the holding portion 381 that holds the hologram master 3 to move the hologram master 3 closer to and farther away from the workpiece 1. In the example of FIG. 1 , the workpiece 1 is transported substantially horizontally in the exposure unit C, so the movement mechanism 382 moves the hologram master 3 up and down. As shown by the two-dot chain line in Figure 3, the movement mechanism 382 moves the holder 381 holding the hologram master 3 upward, thereby separating the hologram master 3 from the material to be processed 1. The movement mechanism 382 also moves the holder 381 downward, thereby positioning the hologram master 3 with a gap from the material to be processed 1. A conventionally known actuator such as a pneumatic cylinder or a rack and pinion can be used as the movement mechanism 382. The movement mechanism 382 may be configured to move the hologram master 3 a predetermined amount in the width direction and / or the transport direction.

[0029] (Supply hole) The hologram master 3 has a supply hole 5 formed therein for supplying a refractive index matching liquid. The supply hole 5 penetrates the hologram master 3 in the thickness direction. In the illustrated example, the thickness direction is approximately parallel to the normal direction. The supply hole 5 penetrates in the thickness direction and communicates with a gap S defined by the hologram master 3 and the material 1 to be processed. The gap between the hologram master 3 and the material 1 to be processed can be filled with a refractive index matching liquid through the supply hole 5. Supply holes 5 are formed in an area that does not have master hologram 31. If supply holes 5 were formed so as to penetrate master hologram 31, the coherent light incident on master hologram 31 would be scattered by the supply holes, and the interference fringes of master hologram 31 might not be accurately recorded in photosensitive layer 11.

[0030] The diameter of supply hole 5 is not particularly limited, but if it is too small, it may be difficult to pour the refractive index matching liquid, and if it is too large, it may reduce the strength of hologram master 3. From this perspective, diameter 5Y of supply hole 5 is, for example, 0.5 mm to 10 mm, and preferably 2 mm to 8 mm (see FIG. 4). It is sufficient that at least one supply hole 5 is provided within the surface of the hologram master 3. It is preferable to provide multiple supply holes 5, as this allows the refractive index matching liquid to be filled in a shorter time. In the illustrated example, when viewed in the width direction of the material to be processed 1, multiple supply holes 5 are provided along the width direction, and when viewed in the longitudinal direction of the material to be processed 1, multiple supply holes 5 are provided along the longitudinal direction. Therefore, the supply holes 5 are arranged in a grid pattern in the area not having the master hologram 31. When a plurality of supply holes 5 are provided, the interval between adjacent supply holes 5 is not particularly limited, but is, for example, 20 mm to 150 mm, preferably 30 mm to 100 mm, and more preferably 40 mm to 60 mm, because this allows filling with the refractive index matching liquid in a relatively short time. The interval refers to the interval 5W1 between adjacent supply holes 5 in the width direction or the interval 5W2 between adjacent supply holes 5 in the length direction (see FIG. 4).

[0031] When a plurality of supply holes 5 are provided, the area of ​​the hologram master 3 (overlapping member) per supply hole 5 is, for example, 1000 mm 2 ~30,000mm 2 and preferably 2000 mm 2 ~25,000mm 2 is. The area of ​​the hologram master 3 (overlapping member) per one supply hole 5 is calculated by the following formula. Formula: Area of ​​hologram master 3 (overlapping member) per supply hole 5 = Area of ​​hologram master 3 / Number of supply holes 5.

[0032] Furthermore, supply holes 5 are formed in an area where coherent light for recording interference fringes in the photosensitive layer 11 does not propagate. As will be described later, during exposure, diffracted light and its reflected light generated by master hologram 31 propagate in one direction (e.g., the longitudinal direction) of the workpiece 1. If supply holes 5 are formed in the direction in which the diffracted light or reflected light (both of which are coherent light) propagate, the light will be scattered by the supply holes. To prevent this, supply holes 5 are formed in an area where coherent light does not propagate. In the illustrated example, a plurality of supply holes 5 are formed at predetermined intervals in the region not having the master hologram 31 in the width direction and in the region not having the master hologram 31 in the length direction.

[0033] Furthermore, a supply device is provided to supply a refractive index matching liquid to the supply hole 5 . As shown in FIGS. 1 and 3 , the supply device includes a tank 511 that stores a refractive index matching liquid, a tube 512 connected to the tank 511, an insertion portion 513 provided at the tip of the tube 512, and an opening / closing portion 514 such as a valve. The tube 512 is a flexible tube so that it can follow the movement of the hologram master 3. When the holding portion 381 of the master mounting member 38 holds the second surface of the hologram master 3 as in this embodiment, the holding portion 381 has a communication hole 383 that communicates with the supply hole 5. As shown in FIG. 3 , the insertion portion 513 is inserted into the communication hole 383. When the opening / closing portion 514 is opened, the refractive index matching liquid in the tank 511 flows through the tube 512 into the supply hole 5, and the refractive index matching liquid is filled into the gap S from the supply hole 5. 3 does not show the tank, the opening / closing part, and the upper part of the tube 512. Also, in FIG. 3, the tube 512 and the insertion part 513 are not shown in cross section (the same applies to the other figures).

[0034] (transparent plate) The light-transmitting plate 41 is disposed on the opposite side of the master hologram 31. The material 1 to be processed is interposed between the light-transmitting plate 41 and the hologram master 3. For example, the light-transmitting plate 41 is made of a plate having the same area as the hologram master 3 or a larger or smaller area than the hologram master 3 . The thickness of the light-transmitting plate 41 is set appropriately, but if it is too small, there is a risk of breakage, and if it is too large, it is not preferable in terms of cost-effectiveness. From these points of view, the thickness of the light-transmitting plate 41 is 10 mm to 50 mm, and preferably 25 mm to 45 mm. The light-transmitting plate 41 is made of a material that transmits coherent light. For example, the light-transmitting plate 41 is made of a material with a refractive index of about 1.5. Examples of materials with a refractive index of about 1.5 include glass, TAC (triacetyl cellulose), polycarbonate, and other resins. Examples of the glass include alkali-free glass, low-alkali glass, borosilicate glass, and soda-lime glass.

[0035] (others) A wiping unit 281 for wiping off the refractive index matching liquid is provided in the exposure unit C. For the wiping unit 281, for example, a wiping roll with a liquid absorbing material on its circumferential surface can be used. Furthermore, the exposure section C is provided with a pressure roll 282 for bringing the material 1 into close contact with the light-transmitting plate. Furthermore, a bleaching unit 29 is provided downstream of the exposure unit C. The bleaching unit 29 irradiates the workpiece 1 with UV / VIS light of a relatively high intensity, but not enough to damage the material forming the photosensitive layer 11. The exposed photosensitive layer 11 is bleached by the irradiation, and the photoreaction of the photosensitive layer 11 (the area irradiated with coherent light and the area not irradiated with coherent light) is completed.

[0036] {Method for manufacturing the hologram of the first embodiment} Next, a method for manufacturing a hologram will be described. The manufacturing method of the present invention includes a placement step of placing an overlapping member on one side of a workpiece having an unexposed photosensitive layer with a gap therebetween, a filling step of filling the gap between the workpiece and the overlapping member with a refractive index matching liquid, and an exposure step of irradiating the photosensitive layer with coherent light after filling the refractive index matching liquid, thereby recording interference fringes in the photosensitive layer. In this embodiment, the overlapping member is a hologram master. In the filling step, the refractive index matching liquid is filled into the gap through supply holes 5 formed in the hologram master 3.

[0037] To manufacture the replica hologram, for example, the manufacturing apparatus A described above is used. As shown in FIG. 8 , the moving mechanism 382 separates the hologram master 3 from the support substrate 12 of the material 1, and the transport unit B transports the material 1 downstream in the transport direction by a predetermined length. The transport of the material 1 at the exposure unit C is then stopped. This predetermined length corresponds to the portion of the photosensitive layer 11 that has been exposed. Next, the pressure roll 282 is moved downstream in the transport direction while in contact with the second surface of the support substrate 12 (the movement of the pressure roll 282 is indicated by a two-dot chain line). This causes the first surface of the photosensitive layer 11 of the material 1 to adhere to the second surface of the light-transmitting plate. Because the photosensitive layer 11 has slight adhesiveness, lightly pressing the material 1 with the pressure roll 282 allows the photosensitive layer 11 of the material 1 to adhere to the second surface of the light-transmitting plate without creating an air interface between the photosensitive layer 11 and the light-transmitting plate.

[0038] <Placement process> Next, as shown in FIGS. 1 and 3, the hologram master 3 is lowered by the movement mechanism 382 and brought close to one surface (second surface) of the support substrate 12 of the material to be processed 1. In other words, the hologram master 3, which is an overlapping member, is placed on one surface of the support substrate 12 of the material to be processed 1 with a gap therebetween. More specifically, when the hologram master 3 is lowered, the first surface of the hologram master 3 faces the second surface of the support substrate 12 of the material to be processed 1 with a gap S therebetween (see FIG. 3). Because the support substrate 12 is not adhesive, the gap S exists between the first surface of the hologram master 3 and the support substrate 12 of the material to be processed 1. The gap S is, for example, a gap of about 1 μm to 30 μm.

[0039] <Filling process> An air interface is generated due to the presence of the gap S. For this reason, the gap S between the first surface of the hologram master 3 and the support substrate 12 of the processing target 1 is filled with a refractive index matching liquid. The refractive index matching liquid may be any liquid that has been publicly known or that will become publicly known after the filing of this application. The refractive index matching liquid is a liquid having a refractive index approximately equal to that of the light-transmitting plate 41. For example, the refractive index matching liquid may be a silicone oil, whose refractive index is similar to that of glass. The silicone oil or other oil components are also called index oil or matching oil. The opening / closing portion 514 is opened, and the refractive index matching liquid in the tank 511 is supplied to the supply hole 5. As shown in FIG. 9(a), the refractive index matching liquid 7 supplied from the tube 512 flows into the gap S from the supply hole 5. The refractive index matching liquid 7 may be supplied by applying pressure. When the refractive index matching liquid 7 is supplied from above as in this embodiment, the refractive index matching liquid 7 flows into the gap S due to its own weight without applying pressure. In particular, since the gap S is very small, the refractive index matching liquid 7 that has entered the supply hole 5 quickly spreads into the gap S due to capillary action. 9(b), when the entire gap S is filled with the refractive index matching liquid 7, the opening / closing unit 514 is closed, and the supply of the refractive index matching liquid 7 is stopped. The amount of refractive index matching liquid 7 to be filled into the entire gap S can be set in advance based on the size of the gap S and the area of ​​the hologram master 3, and the supply of the refractive index matching liquid 7 is stopped according to that set amount. Alternatively, a sensor (not shown) may detect when the entire gap S has been filled with the refractive index matching liquid 7, and the supply of the refractive index matching liquid may be stopped at that timing. In this way, a laminate consisting of a hologram master 3 / refractive index matching liquid 7 / processed material 1 (support substrate 12 + photosensitive layer 11) / transparent plate 41, in which there is no air interface between the layers, is temporarily formed in the exposure section C.

[0040] By utilizing the supply holes 5, the task of filling the gap S with the refractive index matching liquid 7 can be easily performed. Furthermore, since a plurality of supply holes 5 are formed, the refractive index matching liquid 7 can be filled into the gap S in a short time. In particular, since the supply holes 5 are arranged at intervals of 20 mm to 150 mm, the refractive index matching liquid 7 can be filled into the gap S in an extremely short time. The ability to fill the refractive index matching liquid 7 in a short time improves the production efficiency of holograms.

[0041] <Exposure process> 1, coherent light L1 is irradiated onto master hologram 31 from the first surface side of light-transmitting plate 41 of this laminate, exposing photosensitive layer 11 to create a duplicate hologram in photosensitive layer 11 having interference fringes similar to those of master hologram 31. For example, coherent light L1 is irradiated onto master holograms 31 arranged in the first row, and a duplicate hologram corresponding to each master hologram 31 is created in photosensitive layer 11. The coherent light L1 is shaped to have substantially the same shape and size as the shape of the master hologram 31 in a plan view. However, the coherent light L1 may be larger or smaller than the shape of the master hologram 31. The coherent light L1 for exposing the photosensitive layer 11 may be, for example, red laser light, green laser light, blue laser light, or a composite laser light that is a mixture of at least two types of laser light selected from red laser light, green laser light, and blue laser light. It should be noted that when laser light of a predetermined wavelength (e.g., red laser light) is irradiated onto the master hologram 31 to expose the photosensitive layer 11, the master hologram 31 is naturally produced using laser light of the same wavelength as the laser light of the predetermined wavelength.

[0042] 10 is an explanatory diagram of the state during exposure, in which the exposed portion C is cut along the longitudinal direction at a location including the master hologram 31. However, hatching representing the cut surface is omitted. As shown in Figure 10, coherent light L1 (laser light) irradiated from the first surface side of light-transmitting plate 41 passes through photosensitive layer 11, then enters master hologram 31 and generates diffracted light L2. As diffracted light L2 passes through photosensitive layer 11, interference fringes of master hologram 31 are recorded in photosensitive layer 11. The portion of photosensitive layer 11 where the interference fringes are recorded becomes replica hologram 310. Note that Figure 10 illustrates an example in which coherent light L1 is irradiated parallel to the normal direction of master hologram 31, and the diffracted light travels at an acute diffraction angle, but this is not limiting. Coherent light L1 is irradiated at an angle that reproduces master hologram 31.

[0043] Incidentally, the diffracted light L2 may be internally reflected at the air interface of the light-transmitting plate 41. Reflected light L3 of this diffracted light L2 propagates in one direction (in the illustrated example, the longitudinal direction of the material 1 to be treated) through the stack including the light-transmitting plate 41. As described above, the supply holes 5 are formed in an area where coherent light (such as diffracted light or reflected light) does not propagate. Therefore, even if the reflected light L3 is generated, the reflected light L3 can be prevented from scattering within the stack and propagating in random directions.

[0044] Next, as shown by the two-dot chain line in Figure 1, mirror 64 is moved to the second row, and coherent light L1 is irradiated onto the master holograms 31 arranged in that row, creating a duplicate hologram in photosensitive layer 11. Mirror 64 is then moved to the third row, and a duplicate hologram is created in the same manner. In this way, duplicate holograms corresponding to all of the master holograms 31 on hologram master 3 are created in photosensitive layer 11.

[0045] <Post-process> Thereafter, the moving mechanism 382 moves the hologram master 3 away from the support substrate 12 of the workpiece 1. After the hologram master 3 is moved away, a refractive index matching liquid usually remains on the second surface of the support substrate 12 of the workpiece 1. Therefore, as shown in FIG. 11 , the wiping unit 281 is moved while being in contact with the second surface of the support substrate 12 of the workpiece 1, thereby removing the refractive index matching liquid.

[0046] <Repetitive process> The material 1 is then transported downstream in the transport direction by a predetermined length (the portion that has been exposed), and the transport is stopped. The material 1 is adhered to the second surface of the light-transmitting plate 41 due to the slight adhesiveness of the photosensitive layer 11. Because the slight adhesiveness of the photosensitive layer 11 is very weak, when the transport unit B pulls the material 1, the material 1 separates from the light-transmitting plate 41. However, if the photosensitive layer 11 is difficult to separate from the light-transmitting plate 41, an appropriate peeling means may be provided in the transport unit B, or the light-transmitting plate 41 may be moved away from the material 1 (not shown).

[0047] The exposed material 1 is transported and stopped, returning to the state shown in Figure 8. This sends the exposed photosensitive layer 11 downstream, and the unexposed photosensitive layer 11 is subsequently placed in the exposure section C. After this, the photosensitive layer 11 of the material 1 is brought into close contact with the light-transmitting plate 41, the hologram master 3 is placed on the support substrate 12 of the material 1 with a gap S therebetween, a refractive index matching liquid is filled into the gap S through the supply hole 5, exposure is performed to create duplicate holograms in the photosensitive layer 11 corresponding to all the master holograms 31, the hologram master 3 is released, the material 1 is transported a predetermined length, and the process is stopped. This process is repeated. In this manner, duplicate holograms can be continuously created.

[0048] Figure 12(a) is a plan view of an exposed material 100. The exposed material 1 has a plurality of holograms arranged continuously in its photosensitive layer 11. Hereinafter, the "exposed material 100" will be referred to as the "hologram continuum 100." The above example illustrates the use of three rows of master holograms 31, so the hologram continuum 100 in Figure 12(a) has a plurality of duplicate holograms 310 arranged in three rows.

[0049] As shown in Figure 1, hologram continuum 100 is subjected to a bleaching treatment in bleaching unit 29. Protective film 15 and release liner 16 are laminated to bleached hologram continuum 100 in film laminating unit 25 and liner laminating unit 26, respectively, and then the laminate is taken up by winding unit 27.

[0050] If necessary, hologram continuum 100 may be divided into individual hologram rows, and then the rows may be individually wound up on winding section 27. For example, as shown in FIG. 12(b), multi-row hologram continuum 100 may be divided into single-row hologram continuums 100 using slitter 290, and then these may be individually wound up. It is generally preferable that division by slitter 290 be performed after protective film 15 and release liner 16 have been attached to each other.

[0051] {Uses of holograms} By cutting the hologram continuum 100 at appropriate points, individual holograms can be obtained. The applications of the fabricated holograms are not particularly limited. The fabricated holograms can be applied to a variety of applications that have been publicly known or will become publicly known in the future. Holograms can be used, for example, in optical-related products such as light guide plates; security-related products such as anti-counterfeiting seals and authentication seals; and design-related products such as decorative items. A light guide plate according to one embodiment has a hologram manufactured by the above-described manufacturing apparatus and manufacturing method. For example, a light guide plate can be constructed by sandwiching the manufactured hologram between two glass plates or transparent resin plates. Furthermore, a light guide plate for an AR device can be manufactured using the hologram. An AR (Augmented Reality) device is a device, such as smart glasses, that can project text information and virtual content simultaneously with the real world. In such a device, light corresponding to the text information or virtual content (light of red wavelength, light of green wavelength, and light of blue wavelength) is guided by a light guide plate to a position where light from the real world is received.

[0052] For example, the above-mentioned manufacturing apparatus A (or manufacturing method) can also produce a duplicate hologram that is a set of one rectangular hologram called an incoupling and one large rectangular hologram called an outcoupling. As shown in FIG. 13, a light guide plate G for an AR device can be constructed by laminating, in order, a red hologram 310R consisting of incouplings 311R and outcouplings 312R, a green hologram 310G consisting of incouplings 311G and outcouplings 312G, and a blue hologram 310B consisting of incouplings 311B and outcouplings 312B, and then laminating glass plates or transparent resin plates on the front and back surfaces of the laminate.

[0053] [Second embodiment] In the first embodiment, the supply holes 5 are provided in the hologram master 3, but the supply holes 5 may also be provided in the light-transmitting plate 41. In other words, the overlapping member in which the supply holes 5 are formed may be the light-transmitting plate 41.

[0054] {Hologram manufacturing apparatus according to the second embodiment} Fig. 14 is a side view of the manufacturing apparatus A of this embodiment, Fig. 15 is a plan view of the exposure unit in the manufacturing apparatus as seen from above, and Fig. 16 is an enlarged cross-sectional view of the exposure unit cut along the transport direction. Note that the refractive index matching liquid supply device is omitted in Fig. 15. The structural differences between the manufacturing apparatus of the first embodiment and that of the present embodiment are that the manufacturing apparatus A of the present embodiment has a light-transmitting plate 41 arranged above the material to be processed 1 and a hologram master 3 arranged below the material to be processed 1, and that a supply hole 5 is provided in the light-transmitting plate 41.

[0055] Regarding the manufacturing apparatus A of this embodiment, we will explain the configuration and effects that are different from the manufacturing apparatus A of the first embodiment described above, and for similar configurations, the terms or symbols will be used as they are, and explanations of the configuration may be omitted (the same applies to the third embodiment and beyond).

[0056] The hologram master 3 is disposed below the material to be processed 1. Therefore, the photosensitive layer 11 of the material to be processed 1 faces the hologram master 3. The hologram master 3 is held by a master mounting member. The hologram master 3 may be configured to be movable in the vertical direction, or may be fixed so that it cannot move. The light-transmitting plate 41 is disposed above the material to be treated 1. The light-transmitting plate 41 can be moved up and down as shown by the two-dot chain line in Fig. 16. Note that the plate mounting member of the light-transmitting plate 41 and the mechanism for moving the light-transmitting plate 41 up and down are not shown. When the light-transmitting plate 41 is lowered, the first surface of the light-transmitting plate 41 faces one surface (second surface) of the support substrate 12 of the material to be treated 1 with a gap S therebetween. The coherent light L1 is irradiated from the side (upper side) of the light-transmitting plate 41. Note that in Fig. 14, the light source that irradiates the coherent light L1 is not shown, and only the coherent light L1 is shown.

[0057] Supply holes 5 are provided in the surface of the light-transmitting plate 41. The supply holes 5 penetrate the light-transmitting plate 41 in the thickness direction. The supply holes 5 that penetrate in the thickness direction communicate with a gap S defined by the light-transmitting plate 41 and the material to be processed 1. The supply holes 5 are parallel to the thickness direction, but may also penetrate at an angle relative to the thickness direction. The gap S between the hologram master 3 and the material to be processed 1 can be filled with a refractive index matching liquid through the supply holes 5. Supply holes 5 are formed in an area other than the area corresponding to master hologram 31. In other words, supply holes 5 are formed in the area of ​​light-transmitting plate 41 that does not correspond to master hologram 31. The dashed-dotted line in Figure 15 represents the outline of master hologram 31 that exists when light-transmitting plate 41 and the like are viewed in plan view. Master hologram 31 exists below the area surrounded by this dashed-dotted line. No supply holes 5 are formed in the area corresponding to this master hologram 31 (the area surrounded by the dashed-dotted line). If supply holes 5 were formed in this area, when coherent light L1 is irradiated from light-transmitting plate 41, the light L1 would scatter, and the interference fringes of master hologram 31 may not be accurately recorded in photosensitive layer 11.

[0058] The supply holes 5 are formed in an area where coherent light for recording interference fringes on the photosensitive layer 11 does not propagate. In the illustrated example, a plurality of supply holes 5 are formed at predetermined intervals in an area not corresponding to the master hologram 31 in the width direction and an area not corresponding to the master hologram 31 in the length direction. The diameter of the supply holes 5, the spacing between adjacent supply holes 5, and the area of ​​the light-transmitting plate 41 (overlapping member) per supply hole 5 are as described in the (supply holes) section of the first embodiment above.

[0059] {Method for manufacturing the hologram of the second embodiment} In this embodiment, the overlapping member is a light-transmitting plate 41. Then, in the filling step, the gap is filled with a refractive index matching liquid through the supply holes 5 formed in the light-transmitting plate 41.

[0060] The light-transmitting plate 41 is raised to separate it from the support substrate 12 of the material 1 to be processed, and the material 1 to be processed is transported downstream in the transport direction by a predetermined length by the transport section B, and the transport of the material 1 to be processed is stopped in the exposure section C. Next, the pressure roll 282 is moved to bring the photosensitive layer 11 of the material 1 into close contact with the hologram master 3.

[0061] <Placement process> Next, the light-transmitting plate 41 is lowered to approach one surface (first surface) of the supporting substrate 12 of the material to be treated 1. In other words, the light-transmitting plate 41, which is an overlapping member, is placed on one surface of the supporting substrate 12 of the material to be treated 1 with a gap S therebetween (see FIG. 16).

[0062] <Filling process> The opening and closing part 514 is opened, and the refractive index matching liquid in the tank 511 is supplied to the supply hole 5. The refractive index matching liquid supplied from the tube 512 flows into the gap S from the supply hole 5, similar to the first embodiment. In this way, a laminate consisting of a light-transmitting plate 41 / refractive index matching liquid 7 / processed material 1 (support substrate 12 + photosensitive layer 11) / hologram master 3, in which there is no air interface between the layers, is temporarily formed in the exposure section C.

[0063] <Exposure process> 14 , coherent light L1 is irradiated onto the master holograms 31 in the first row from the first surface side of light-transmitting plate 41 of this laminate, exposing the photosensitive layer 11. As in the first embodiment, this exposure allows duplicate holograms having interference fringes similar to those of the master holograms 31 to be produced in the photosensitive layer 11. Coherent light L1 is irradiated onto the master holograms 31 arranged in the second and third rows, producing duplicate holograms in the photosensitive layer 11.

[0064] <Post-process> Thereafter, the light-transmitting plate 41 is separated from the supporting substrate 12 of the object 1 to be treated, and the wiping part 281 removes the refractive index matching liquid adhering to the supporting substrate 12 .

[0065] <Repetitive process> The exposed material 1 is then transported downstream, the photosensitive layer 11 of the unexposed material 1 is brought into close contact with the hologram master 3, a light-transmitting plate 41 is placed on the support substrate 12 of the material 1 with a gap S therebetween, a refractive index matching liquid is filled into the gap S through the supply holes 5, exposure is performed to create duplicate holograms in the photosensitive layer 11 corresponding to all the master holograms 31, the light-transmitting plate 41 is released, the material 1 is transported a predetermined length, and the process is then stopped. This process is repeated. Duplicate holograms can be created continuously in this manner.

[0066] [Third embodiment] In the first and second embodiments, the hologram master 3 is used to replicate the interference fringes of the master hologram 31 onto the photosensitive layer 11. However, the hologram may be produced using a prism (without using the hologram master 3). In this case, the supply holes 5 are formed in the prism. That is, the overlapping member in which the supply holes 5 are formed may be a prism.

[0067] {Hologram manufacturing apparatus according to the third embodiment} Fig. 17 is a side view of the manufacturing apparatus A of this embodiment, Fig. 18 is a plan view of the exposure unit in the manufacturing apparatus as seen from above, and Fig. 19 is an enlarged cross-sectional view of the exposure unit cut along the transport direction. Note that the refractive index matching liquid supply device is omitted in Fig. 18. The structural difference between the manufacturing apparatus of the first embodiment and that of the present embodiment is that the manufacturing apparatus A of the present embodiment is provided with a prism 9 instead of a hologram master 3, and that the prism 9 is provided with a supply hole 5.

[0068] 18, the prism 9 extends in the width direction. The prism 9 may be slightly shorter than the material 1 to be treated in the width direction, as in the illustrated example, or may be the same length as or longer than the material 1 to be treated in the width direction. The prism 9 has a refractive index approximately equal to that of the light-transmitting plate 41. At least one prism 9 is required. In the illustrated example, three prisms 9 are arranged in a line in the longitudinal direction of the material 1 to be treated. The material 1 to be treated is interposed between each prism 9 and a light-transmitting plate 41. Furthermore, as indicated by the two-dot chain line in FIG. 19, the prism 9 is configured to be movable so that it can be moved closer to or farther away from the material 1 to be treated. For example, the prism 9 is attached to a mounting member (not shown) equipped with a movement mechanism, and can be moved closer to or farther away from the material 1 to be treated by driving the movement mechanism. When the prism 9 is lowered, the lower surface of the prism 9 faces one surface of the support substrate 12 of the material 1 to be treated, with a gap S therebetween. Furthermore, the light source (not shown) is configured so as to be able to emit coherent light L1 from the first surface side of the light-transmitting plate and to emit coherent light L11 from the prism 9 side.

[0069] A supply hole 5 is provided in the surface of the prism 9. The supply hole 5 penetrates the prism 9 in the thickness direction. In the illustrated example, the thickness direction is approximately parallel to the normal direction. The supply hole 5 penetrating in the thickness direction communicates with a gap S defined by the prism 9 and the material 1 to be treated. The supply hole 5 may also be penetrating at an angle with respect to the thickness direction. The gap S between the prism 9 and the material 1 to be treated can be filled with a refractive index matching liquid through the supply hole 5. The supply hole 5 is formed excluding the area through which the coherent light L11 irradiated from the prism 9 side passes. In other words, the supply hole 5 is formed in the area of ​​the prism 9 through which the coherent light L11 does not pass. 18 indicates the region through which coherent light L11 irradiated from the prism 9 side passes. No supply holes 5 are formed in the region surrounded by the dashed dotted line. If supply holes 5 were formed in this region, when coherent light L11 is irradiated through the prism 9, the light would be scattered, and interference fringes may not be accurately recorded on the photosensitive layer 11. The diameter of the supply holes 5, the spacing between adjacent supply holes 5, and the area of ​​the light-transmitting plate 41 (overlapping member) per supply hole 5 are as described in the (supply holes) section of the first embodiment above.

[0070] {Method for manufacturing the hologram of the third embodiment} In this embodiment, the overlapping member is a prism 9. Then, in the filling step, a refractive index matching liquid is filled into the gap through the supply holes 5 formed in the prism 9.

[0071] The prism 9 is raised and separated from the support substrate 12 of the material to be treated 1, and the material to be treated 1 is transported downstream in the transport direction by a predetermined length by the transport unit B, where it is stopped. Next, the pressure roll 282 is moved to bring the photosensitive layer 11 of the material to be treated 1 into close contact with the light-transmitting plate 41.

[0072] <Placement process> Next, the prism 9 is lowered to approach one surface of the support substrate 12 of the material to be treated 1. In other words, the prism 9, which is an overlapping member, is placed on one surface of the support substrate 12 of the material to be treated 1 with a gap S therebetween (see FIG. 19).

[0073] <Filling process> The opening and closing part 514 is opened, and the refractive index matching liquid in the tank 511 is supplied to the supply hole 5. The refractive index matching liquid 7 supplied from the tube 512 flows into the gap S from the supply hole 5, as in the first embodiment (see FIG. 20). In this way, a laminate consisting of the prism 9 / refractive index matching liquid 7 / processing target 1 (support substrate 12+photosensitive layer 11), with no air interface between the layers, is temporarily formed in the exposure section C.

[0074] <Exposure process> As shown in Figures 17 and 21, coherent light L1 is irradiated onto the material to be treated 1 from the first surface side of the light-transmitting plate 41, and coherent light L11, which is irradiated from the prism 9 side in a direction different from that of the coherent light L1, is irradiated onto the material to be treated 1. To suppress reflection and refraction, the coherent light L11 is irradiated onto the material to be treated 1 through the prism 9. The coherent light L1 and the coherent light L11 travel in different directions but are light of the same wavelength (for example, laser light of the same wavelength). For example, light emitted from a laser oscillator of a predetermined wavelength is split by a polarizing beam splitter, the polarization axis of one of the split light beams is rotated by a half-wave plate to match the polarization axis of the other light beam, and the light is magnified and flattened by a magnifying lens and a collimating lens, respectively, and each of the split light beams is then reflected appropriately by a mirror. This allows the photosensitive layer 11 of the material to be processed 1 to be irradiated with coherent light beams L1 and L11 of the same wavelength from different directions. 21, the photosensitive layer 11 is exposed to the coherent light beams L1 and L11 emitted in two directions, and interference fringes are recorded. That is, a hologram 311 is formed in the photosensitive layer 11. Similarly, the three prisms 9 are irradiated with coherent light L11, and a corresponding hologram 311 is formed in the photosensitive layer 11.

[0075] <Post-process> Thereafter, the prism 9 is separated from the support substrate 12 of the object 1 to be treated, and the refractive index matching liquid adhering to the support substrate 12 is removed by the wiping part 281 .

[0076] <Repetitive process> Thereafter, the exposed material 1 is transported, the photosensitive layer 11 of the material 1 is brought into close contact with the light-transmitting plate 41, the prism 9 is placed on the support substrate 12 of the material 1 with a gap S therebetween, the gap S is filled with a refractive index matching liquid through the supply hole 5, coherent light L1 and L11 is irradiated from two directions to create a hologram in the photosensitive layer 11, the prism 9 is released, the material 1 is transported a predetermined length, and the process is stopped.These operations are repeated in this manner, allowing holograms to be continuously created in the photosensitive layer 11.

[0077] [Fourth embodiment] In each of the above embodiments, the case where the refractive index matching liquid is supplied to the supply hole 5 from above has been exemplified, but this is not limiting. For example, the refractive index matching liquid may be supplied to the supply hole 5 from below. In this case, it may be difficult to fill the gap with the refractive index matching liquid due to its own weight, so it is preferable to supply the refractive index matching liquid under pressure. Furthermore, when the refractive index matching liquid is supplied from below, for example, the hologram master 3 having the supply holes 5 of the first embodiment described above may be placed below the material to be processed 1 (in this case, the light-transmitting plate 41 is placed above the material to be processed 1). Similarly, when the refractive index matching liquid is supplied from below, for example, the light-transmitting plate 41 having the supply holes 5 of the second embodiment described above may be placed below the material to be processed 1, or the prism 9 having the supply holes 5 of the third embodiment described above may be placed below the material to be processed 1. [Explanation of symbols]

[0078] A Hologram manufacturing equipment B. Manufacturing equipment conveying section C. Exposure section of manufacturing equipment D Light source for manufacturing equipment S Gap between overlapping material and treated material 1. Material to be treated 11 Photosensitive layer 12 Supporting base material 3 Hologram master (layered material) 31 Master Hologram 41 Translucent plate (layered member) 5 Supply hole 7 Refractive index matching liquid 9 Prism (layered member)

Claims

1. a placement step of placing an overlapping member with a gap on one side of a processing object having an unexposed photosensitive layer; a filling step of filling a gap between the material to be treated and the overlapping member with a refractive index matching liquid; an exposure step of irradiating the photosensitive layer with coherent light after filling the refractive index matching liquid, thereby recording interference fringes on the photosensitive layer; The method for manufacturing a hologram, wherein the overlapping member has a supply hole that communicates with the gap, and the refractive index matching liquid is filled into the gap through the supply hole.

2. 2. The method for producing a hologram according to claim 1, wherein the supply holes are formed in a region of the overlapping member through which coherent light for recording interference fringes on the photosensitive layer does not propagate.

3. 2. The method for producing a hologram according to claim 1, wherein the diameter of the supply hole is 0.5 mm to 10 mm.

4. The method for producing a hologram according to claim 1 , wherein a plurality of the supply holes are formed at intervals.

5. 5. The method for producing a hologram according to claim 4, wherein the interval between the adjacent supply holes is 20 mm to 150 mm.

6. the processing target material has a supporting substrate and the photosensitive layer provided on the supporting substrate, The method for manufacturing a hologram according to claim 1 , wherein in the arranging step, the overlapping member is arranged on one surface of the support base material of the processing object with the gap therebetween.

7. The method for producing a hologram according to claim 1 , wherein the overlapping member is a hologram master having a master hologram.

8. The method for manufacturing a hologram according to claim 1 , wherein the overlapping member is a light-transmitting plate.

9. The method for producing a hologram according to claim 1 , wherein the overlapping member is a prism.

10. A light guide plate having a hologram manufactured by the manufacturing method according to claim 1 .

11. In a hologram master used to replicate a hologram, a region in which a master hologram is formed and a region in which the master hologram is not formed, A hologram master plate having a supply hole for supplying a refractive index matching liquid formed in a region not having the master hologram so as to penetrate the plate in the thickness direction.

Images