Hologram manufacturing device, hologram manufacturing method, and light guide plate

Abstract

To provide a hologram manufacturing device for efficiently manufacturing a plurality of holograms in a photosensitive layer.SOLUTION: A device A comprises: an exposure portion C that includes a master layer 3 having master holograms 31; a conveyance portion B that conveys an unexposed photosensitive layer 11 and arranges the photosensitive layer 11 on a first surface side of the master layer 3 of the exposure portion C; and a light source D that irradiates the master holograms 31 with coherent light from a first surface side of the photosensitive layer 11. The device replicates interference fringes of the master holograms 31 onto the photosensitive layer 11 by exposing the photosensitive layer 11 by transmitting the coherent light and diffracted light generated from the master holograms 31 by the irradiation of the coherent light. The master layer 3 has a plurality of master holograms 31, and the light source D irradiates all the master holograms 31 of the master layer 3 with the coherent light L11 simultaneously.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a hologram manufacturing apparatus and method for manufacturing a hologram by replicating a master hologram. [Background technology]

[0002] A known method for producing a hologram is to use a master hologram and optically replicate the interference fringes of the master hologram onto a photosensitive layer. Briefly, as shown in FIG. 20, a laminate including a master layer containing a master hologram, an unexposed photosensitive layer adhered to the master layer, and a glass plate adhered to the photosensitive layer is irradiated with laser light from the glass plate side. The laser light passes through the glass plate and the photosensitive layer and is incident on the master hologram, generating diffracted light in the master hologram, which then passes through the photosensitive layer. The laser light and the diffracted light interfere with each other to expose the photosensitive layer, thereby recording interference fringes of the master hologram in the photosensitive layer. In this way, the master hologram can be replicated on the photosensitive layer. In other words, a hologram similar to the master hologram can be created in the photosensitive layer.

[0003] For example, Patent Document 1 discloses a duplication method in which an original hologram is attached to a flat portion of a rotating body, a photosensitive film for duplication is wrapped around and tightly attached to the original hologram, the rotating body is intermittently rotated together with the photosensitive film for duplication, and when the rotating body comes to a standstill, reproduction light is irradiated at an angle to reproduce the original hologram, and the hologram information is intermittently reproduced on the photosensitive film for duplication. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-249876 Summary of the Invention

[0005] Patent Document 1 does not disclose or suggest at all how to copy the interference fringes (information) of a plurality of master holograms onto a photosensitive layer or how to irradiate the reproduction light. [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a hologram manufacturing apparatus and method that efficiently produces a plurality of holograms in a photosensitive layer by irradiating a master layer having a plurality of master holograms with coherent light. [Means for solving the problem]

[0007] In one aspect, an apparatus for producing a hologram is provided. A first type of hologram manufacturing apparatus includes an exposure unit having a master layer having a master hologram, a transport unit that transports an unexposed photosensitive layer and positions the photosensitive layer on the first surface side of the master layer in the exposure unit, and a light source that irradiates coherent light onto the master hologram from the first surface side of the photosensitive layer, and reproduces interference fringes of the master hologram on the photosensitive layer by transmitting the coherent light and diffracted light generated from the master hologram by irradiating the coherent light through the photosensitive layer, wherein the master layer has a plurality of master holograms, and the light source irradiates the coherent light simultaneously onto all of the master holograms in the master layer.

[0008] A second embodiment of the hologram manufacturing apparatus is the same as the first embodiment, except that the photosensitive layer is long and strip-shaped, the plurality of master holograms are arranged in multiple columns in the width direction of the photosensitive layer and multiple rows in the transport direction, which is perpendicular to the width direction, and the transport unit transports the long and strip-shaped photosensitive layer a predetermined length in the longitudinal direction and then stops transporting the photosensitive layer. A third embodiment of the hologram manufacturing apparatus is the manufacturing apparatus of the first or second embodiment, wherein the light source has a mask member that trims the expanded and flattened coherent light, and the trimming light that passes through the mask member and is trimmed is irradiated simultaneously onto all master holograms in the master layer, and the ratio of the intensity of the edge of the trimming light to the intensity of the center of the trimming light is 20% to 80%. A fourth embodiment of the hologram manufacturing apparatus is the manufacturing apparatus of any one of the first to third embodiments, wherein the light source has a mask member that trims the expanded and flattened coherent light, the trimming light that has passed through the mask member is irradiated simultaneously onto all master holograms in the master layer, and the ratio of the effective area of ​​the trimming light to the area of ​​the coherent light immediately before passing through the mask member is 5% to 60%. A fifth embodiment of the hologram manufacturing apparatus is the manufacturing apparatus of the third or fourth embodiment, wherein the light source further includes an oscillator of the coherent light and a reflector that changes the direction of light toward the master hologram, and the mask member is disposed between the oscillator and the reflector or between the reflector and the photosensitive layer.

[0009] In another aspect, a method for producing a hologram is provided. A sixth embodiment of the method for manufacturing a hologram includes a transport step of transporting an unexposed photosensitive layer to the first surface side of a master layer having a master hologram, and an exposure step of irradiating the photosensitive layer with coherent light from the first surface side after placing the photosensitive layer on the first surface side of the master layer, in which the coherent light and diffracted light generated from the master hologram by irradiating the coherent light are transmitted through the photosensitive layer to expose it, thereby replicating interference fringes of the master hologram in the photosensitive layer, in which the master layer has a plurality of master holograms, and in the exposure step, the coherent light is irradiated simultaneously onto all of the master holograms in the master layer.

[0010] A seventh aspect of the hologram manufacturing method is the same as the sixth aspect, except that the magnified and flattened coherent light is passed through a mask member to perform trimming, and the trimming light that has passed through the mask member and been trimmed is irradiated simultaneously onto all master holograms in the master layer, and the ratio of the intensity of the edge of the trimming light to the intensity of the center of the trimming light is 20% to 80%. The eighth aspect of the hologram manufacturing method is the same as the sixth or seventh aspect, except that the magnified and flattened coherent light is trimmed by passing it through a mask member, and the trimming light that has passed through the mask member and been trimmed is simultaneously irradiated onto all master holograms in the master layer, and the ratio of the effective area of ​​the trimming light to the area of ​​the coherent light immediately before passing through the mask member is 5% to 60%. [Effects of the Invention]

[0011] According to the manufacturing apparatus and manufacturing method of the present invention, it is possible to efficiently replicate a plurality of holograms in a photosensitive layer. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a side view of the hologram manufacturing apparatus according to the first embodiment. [Figure 2] FIG. [Figure 3] FIG. 2 is a perspective view of an exposure unit and a light source of the manufacturing apparatus. [Figure 4] FIG. 4 is an enlarged cross-sectional view taken along line IV-IV in FIG. 2. [Figure 5] A bottom view of the master layer, seen from the first side. [Figure 6] FIG. 2 is a bottom view of the light-transmitting plate, seen from below. [Figure 7] FIG. 4 is a perspective view of a first light-transmitting plate of the light-transmitting plate, viewed from below. [Figure 8] FIG. 10 is a reference side view of the exposure unit, showing one mode in which reflected light of diffracted light is unlikely to be incident on a replica hologram. [Figure 9]FIG. 10 is a reference side view of the exposure unit, showing another aspect in which reflected light of diffracted light is less likely to enter the duplicate hologram. [Figure 10] A reference diagram showing how to create a master hologram. [Figure 11] FIG. 2 is a side view of a manufacturing apparatus for explaining steps in a method for manufacturing a hologram. [Figure 12] A plan view of a replica hologram continuum in which holograms are produced successively. [Figure 13] FIG. 10 is a reference side view of a light guide plate on which a red duplicate hologram, a green duplicate hologram, and a blue duplicate hologram are stacked. [Figure 14] FIG. 10 is a perspective view of an exposure unit and a light source according to a second embodiment. [Figure 15] FIG. 11 is a reference side view of an exposure unit according to a first example of the third embodiment. [Figure 16] FIG. 13 is a reference side view of an exposure unit according to a second example of the third embodiment. [Figure 17] FIG. 10 is a cross-sectional view of an exposure unit according to a fourth embodiment. [Figure 18] FIG. 10 is a reference diagram showing an example of the arrangement of master holograms used in the examples. [Figure 19] FIG. 10 is a reference diagram showing a laser beam and a trimming beam used in the examples. [Figure 20] FIG. 1 is a reference diagram for explaining a conventional method for replicating a hologram. DETAILED DESCRIPTION OF THE INVENTION

[0013] [First embodiment] One embodiment will be described below with reference to the drawings. In this specification, the "first surface" of a certain member (e.g., a master layer 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 member 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.

[0014] {Hologram manufacturing equipment} 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, Fig. 3 is a perspective view showing the exposure unit and light source in the manufacturing apparatus, and Fig. 4 is an enlarged cross-sectional view of the exposure unit cut along the conveyance direction. In Figs. 2 and 3, both sides of the long strip-shaped material to be processed are omitted. Also, in Fig. 3, the master mounting member for mounting the master layer and the plate mounting member for mounting the light-transmitting plate are omitted. 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.

[0015] The hologram manufacturing apparatus 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 the hologram in the photosensitive layer. In this specification, the hologram replicated in the photosensitive layer may be referred to as a "replica hologram." The photosensitive layer applied to the manufacturing apparatus may be in the form of a sheet, but is preferably in the form of a long strip. By loading a long strip of photosensitive layer into the manufacturing apparatus and exposing the photosensitive layer using the manufacturing apparatus, 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. The long strip of 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.

[0016] 1 to 4, the manufacturing apparatus A has a transport section B that transports the photosensitive layer 11 in the longitudinal direction, an exposure section C that exposes the photosensitive layer 11 transported by the transport section B, and a light source D that irradiates coherent light onto a laminate including the photosensitive layer 11 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 to transport the photosensitive layer 11 to the exposure section C, expose the photosensitive layer 11 to light in the exposure section C to form a duplicate hologram, and then transport the photosensitive layer 11 again, repeating this process to continuously produce multiple duplicate holograms.

[0017] <Material to be processed including a photosensitive layer> 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 photosensitive layer 11 typically has a thickness of several μm to 20 μm, and therefore is often not strong enough to withstand transport through the manufacturing equipment A. For this reason, the photosensitive layer 11 is typically formed on a long, strip-shaped support substrate 12. 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, and examples of suitable materials include glass, TAC (triacetyl cellulose), and resins such as polycarbonate. The thickness of the support substrate 12 is not particularly limited and is approximately 10 μm to 100 μm. Hereinafter, a material consisting of the support substrate 12 and the photosensitive layer 11 formed solidly on one surface of the support substrate 12 will be referred to as the "processed material 1."

[0018] 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 the adhesive-attached protective film 15 / the material to be treated 1 (support substrate 12+photosensitive layer 11) / the release liner 16 is wound onto a roll and loaded into the unwinding section of the manufacturing device A.

[0019] <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 thereby enable continuous unwinding and take-up of the material 1, a film laminating section 25 that bonds the adhesive-attached protective film 15 to the exposed material 1, a liner laminating section 26 that bonds the 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.

[0020] 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.

[0021] After the exposure process is completed, the film laminating section 25 and the liner laminating section 26 laminate another adhesive-backed protective film 15 and release liner 16 onto the treated material 1, and the winding section 27 winds up the treated material 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.

[0022] <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 unit C has a master layer 3 including a master hologram 31, a master mounting member 38 for mounting the master layer 3, light-transmitting plates 41, 42, and 43 arranged on the first surface side of the master layer 3, and a plate mounting member 48 for mounting the light-transmitting plates 41, 42, and 43. A material to be processed 1 including a photosensitive layer 11 is interposed between the first surface of the master layer 3 and the second surfaces of the light-transmitting plates 41, 42, and 43.

[0023] (Master layer and master mounting member) Fig. 5 is a bottom view of the master layer 3 as viewed from the first surface side. In other words, Fig. 5 is a view of the master layer 3 (excluding the light-transmitting plate and the material to be processed 1) as viewed from the direction of the white arrow in Fig. 4. Note that since the master hologram 31 is sandwiched between the first substrate 32 and the second substrate 33, it does not appear on the surface when viewed from the first surface side, but for convenience, the master hologram 31 is also represented by a solid line in Fig. 5.

[0024] 1 to 5, the master layer 3 has a plurality of master holograms 31. For example, the master layer 3 has a first substrate 32, a second substrate 33, and a plurality of master holograms 31 interposed between the first substrate 32 and the second substrate 33. The plurality of master holograms 31 are arranged along the surface of the master layer 3 at predetermined intervals. That is, the master holograms 31 are arranged in m columns (m is an integer of 2 or more) in the width direction and n rows (n is an integer of 2 or more) in the transport direction, which is a direction perpendicular to the width direction. Here, m is an integer of 2 or more, and n is an integer of 2 or more. There are no particular restrictions on the upper limits of m and n, but they are each independently, for example, 20 or less, and preferably 15 or less. Note that a "row" refers to a group lined up in the width direction, and a "column" refers to a group lined up in the transport direction (corresponding to the longitudinal direction of the material to be processed 1). In the illustrated example, a total of nine master holograms 31, a 3 x 3 arrangement, are provided on the master layer 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 gaps between each row and column. Therefore, in the illustrated example, three master holograms are lined up in each of the first row S-1, second row S-2, and third row S-3, and three master holograms are lined up in each of the first column R-1, second column R-2, and third column R-3. However, the number and arrangement of master holograms 31 provided on the master layer 3 are not limited to the 3 rows x 3 columns and can be changed as appropriate. The first and second substrates 32, 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 for example, glass, TAC (triacetyl cellulose), polycarbonate or other resins may be used.

[0025] Here, a method for producing a master layer containing a master hologram will be briefly described. The master hologram can be produced by a conventionally known method. FIG. 10 is a reference diagram that schematically shows how a master hologram is produced. As shown in Figure 10(a), a photosensitive layer 1100 made of a photosensitive material is prepared. Examples of the photosensitive material that can be used include photopolymer, photoresist, silver halide emulsion, and dichromated gelatin. In the illustrated example, the photosensitive layer 1100 is interposed between the first and second substrates 3200 and 3300. However, in manufacturing the master hologram, only the photosensitive layer 1100 may be used, or the photosensitive layer 1100 may be provided on the first substrate 3200. Next, a master hologram is produced by irradiating photosensitive layer 1100 with light IL of a predetermined wavelength from two different directions: a direction that forms an angle α with respect to the XY plane (hereinafter referred to as the "α direction") and a direction that forms an angle β with respect to the XY plane (hereinafter referred to as the "β direction"). Specifically, by irradiating photosensitive layer 1100 with interference light of laser light of a predetermined wavelength from two directions, the monomer component in the irradiated portion of photosensitive layer 1100 is diffused, resulting in a refractive index distribution. As a result, interference fringes are recorded in the irradiated portion, resulting in master hologram 3100. To maintain coherence, it is preferable that the light IL of the predetermined wavelength is irradiated from two directions after light emitted from the same laser oscillator 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 coincide with the polarization axis of the other light beam, and the light is magnified and flattened by a magnifying lens and a collimating lens, respectively.

[0026] As shown in Figure 1(b), master hologram 3100 manufactured as described above is irradiated with laser light IL100 of the predetermined wavelength from one direction (β direction) of the two directions (α direction, β direction) in which laser light of the predetermined wavelength was irradiated when master hologram 3100 was produced. In other words, laser light IL100, which is reproduction light, is irradiated at an angle at which master hologram 3100 is reproduced. The light is then diffracted in the other direction (α direction) (diffracted light IL200). When laser light of a red wavelength is irradiated, a red master hologram is generated; when laser light of a green wavelength is irradiated, a green master hologram is generated; and when light of a blue wavelength is irradiated, a blue master hologram is generated.

[0027] Returning to FIG. 4 , a light-absorbing layer 35 is provided on the second surface of the master layer 3. Hereinafter, to distinguish it from a light-absorbing layer provided on a light-transmitting plate, the light-absorbing layer 35 provided on the master layer 3 will be referred to as the "master light-absorbing layer 35." The master light-absorbing layer 35 is laminated at least in an area of ​​the second surface of the master layer 3 that corresponds to the master hologram 31. In the illustrated example, the master light-absorbing layer 35 is laminated over substantially the entire second surface of the master layer 3. Note that when the master layer 3 is composed of only the master hologram 31, or when the master layer 3 is composed of the master hologram 31 and the first substrate 32, the master light-absorbing layer 35 may be laminated at least on the second surface of the master hologram 31. The master light-absorbing layer 35 is provided to absorb the light that has passed through the master hologram 31 when part of the coherent light has passed through the master hologram 31. The master light-absorbing layer 35 also absorbs the light that passes through the portion of the master layer 3 where the master hologram 31 is not provided.

[0028] The material for forming the master light-absorbing layer 35 is not particularly limited, provided that it contains an absorbent capable of absorbing the coherent light. Examples of the absorbent include black colorants such as carbon black, organic dyes, pigments primarily composed of metal oxides, inorganic substances such as metal particles, and other organic substances. Since the light that the absorbent can absorb usually depends on the wavelength of the light, the absorbent is selected taking into consideration the wavelength of the coherent light. For example, as described below, when red, green, and blue laser beams are selectively used as coherent light during exposure, the light-absorbing layer is formed from a material containing an absorbent capable of absorbing all of these laser beams in the visible light region. A typical example of such an absorbent is a black colorant. Alternatively, a mixed absorbent may be used, which is a mixture of a first absorbent that absorbs light with a wavelength of 600 nm to 900 nm, a second absorbent that absorbs light with a wavelength of 450 nm to 750 nm, and a third absorbent that absorbs light with a wavelength of 300 nm to 550 nm. The master light-absorbing layer 35 can be formed by applying a forming material containing an absorbent such as the black colorant, a suitable binder resin, and any additives to the second surface of the master layer 3. The thickness of the master light-absorbing layer 35 is not particularly limited, and is, for example, several μm to 100 μm.

[0029] The master layer 3 is attached to a master mounting member 38. The master mounting member 38 includes a holder 381 that holds the master layer 3 and a movement mechanism 382 that moves the holder 381. The movement mechanism 382 moves the holder 381 holding the master layer 3 to move the master layer 3 closer to or farther from the workpiece 1. In the example shown in FIG. 1, the workpiece 1 is transported substantially horizontally in the exposure section C, so the movement mechanism 382 moves the master layer 3 up and down. As shown by the two-dot chain line in FIG. 4, the movement mechanism 382 moves the holder 381 holding the master layer 3 upward, thereby moving the master layer 3 away from the workpiece 1. Furthermore, the movement mechanism 382 moves the holder 381 downward, thereby bringing the master layer 3 into substantial contact with the workpiece 1. The movement mechanism 382 can be a conventional actuator, such as a pneumatic cylinder or a rack-and-pinion. The movement mechanism 382 may be configured to be able to move the master layer 3 a predetermined amount in the width direction and / or the transport direction.

[0030] (transparent plate) Fig. 6 is a bottom view of the light-transmitting plates 41, 42, and 43 as viewed from the first surface side. In other words, Fig. 6 is a view of the light-transmitting plates 41, 42, and 43 (excluding the material to be processed 1 and the master layer 3) as viewed from the direction of the white arrow in Fig. 4. 1 to 4 and 6, the light-transmitting plates 41, 42, and 43 are members that support the material 1 to be treated, and the material 1 to be treated is interposed between the light-transmitting plates 41, 42, and 43 and the master layer 3. The light-transmitting plates are arranged on the first surface side of the master layer 3. In order to interpose the material 1 to be treated between the light-transmitting plates 41, 42, and 43 and the master layer 3, the light-transmitting plates 41, 42, and 43 are not in close contact with the first surface of the master layer 3, but are arranged on the first surface side of the master layer 3 with a gap therebetween.

[0031] 4, light-transmitting plates 41, 42, and 43 are provided corresponding to at least the master hologram 31. For example, if the master layer 3 includes a plurality of master holograms 31, one light-transmitting plate may be arranged on the first surface side of the master layer 3 corresponding to all of the master holograms 31, or one light-transmitting plate 41 may be arranged corresponding to at least one master hologram 31, and another light-transmitting plate 42 may be arranged corresponding to at least another master hologram 31. In the latter case, a plurality of separate light-transmitting plates are used. In the illustrated example, light-transmitting plates 41, 42, and 43 are arranged corresponding to each row of the master holograms 31. Specifically, as described above, n rows of master holograms 31 are provided on the master layer 3, and therefore n light-transmitting plates are arranged corresponding to each row. In the illustrated example, 3 rows and 3 columns of master holograms 31 are arranged, and therefore three light-transmitting plates 41, 42, and 43 are arranged corresponding to the three rows. Hereinafter, the three light-transmitting plates 41, 42, and 43 are referred to as the "first light-transmitting plate 41," the "second light-transmitting plate 42," and the "third light-transmitting plate 43," respectively. Referring to FIG. 1 , the first light-transmitting plate 41 is located downstream in the transport direction, the second light-transmitting plate 42 is located closer to the unwinding section 21 than the first light-transmitting plate 41, and the third light-transmitting plate 43 is located closer to the unwinding section 21 than the second light-transmitting plate 42. Therefore, the first light-transmitting plate 41 and the second light-transmitting plate 42, and the second light-transmitting plate 42 and the third light-transmitting plate 43 are adjacent to each other in the conveying direction.

[0032] The first light-transmitting plate 41 is disposed on the first surface side of the master layer 3 in correspondence with the three master holograms 31 arranged in the first row S-1. The second light-transmitting plate 42 is disposed on the first surface side of the master layer 3 in correspondence with the three master holograms 31 arranged in the second row S-2. The third light-transmitting plate 43 is disposed on the first surface side of the master layer 3 in correspondence with the three master holograms 31 arranged in the third row S-3. The first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43 are all made of strip-shaped light-transmitting plates extending in the width direction.

[0033] The first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43 may be the same shape and size, or may be the same shape but different sizes, or may be different shapes but different sizes. In the illustrated example, the first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43 are the same shape and size to simplify the equipment. Hereinafter, since the second light-transmitting plate 42 and the third light-transmitting plate 43 have the same configuration as the first light-transmitting plate 41, the configuration of the first light-transmitting plate 41 will be described in detail, and a detailed description of the second light-transmitting plate 42 and the third light-transmitting plate 43 will be omitted. Regarding the second light-transmitting plate 42 and the third light-transmitting plate 43, the terms "first light-transmitting plate 41" and "first row S-1" in the following section on specific examples of the first light-transmitting plate 41 should be read as "second light-transmitting plate 42" and "second row S-2" or "third light-transmitting plate 43" and "third row S-3."

[0034] Specific examples of the first light-transmitting plate 41 Fig. 7 is a perspective view of the first light-transmitting plate 41. Note that in Fig. 7, the first surface of the first light-transmitting plate 41 faces upward on the paper surface. 4, 6, and 7, the first light-transmitting plate 41 is formed in the shape of a rectangular parallelepiped with its longitudinal axis extending in the width direction. The first light-transmitting plate 41 extends in the width direction so as to overlap the three master holograms 31 arranged in the first row S-1 and their surrounding areas in a planar perspective view. The dimensions of the first light-transmitting plate 41 are equal to or larger than the dimensions of the master holograms 31, and preferably larger than the dimensions of the master holograms 31. In this specification, the "dimension" of an object such as a light-transmitting plate refers to the length of the object in a side view (the length in the transport direction in a side view). "Side view" refers to viewing the object from one side in the width direction to the opposite side. The thickness of the first light-transmitting plate 41 is set appropriately, but in order to minimize reflection of diffracted light, it is preferable that the thickness of the first light-transmitting plate 41 is relatively large. For example, the thickness of the first light-transmitting plate 41 is 10 mm to 50 mm, and preferably 25 mm to 45 mm. The first light-transmitting plate 41 is made of a material that transmits coherent light. For example, the first light-transmitting plate 41 (light-transmitting plate) 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] The first light-transmitting plate 41 is provided with light-absorbing layers 51 and 53. The light-absorbing layers 51 and 53 are provided to absorb diffracted light. The diffracted light is light that is diffracted when coherent light enters the master hologram 31. In this embodiment, the light-absorbing layers 51 and 53 are provided on the end faces and the first surface of the first light-transmitting plate 41. The end faces are also called thickness surfaces or side surfaces and refer to surfaces of the first light-transmitting plate 41 other than the first and second surfaces. The rectangular parallelepiped first light-transmitting plate 41 has four end faces. The light-absorbing layer 51 may be provided in a solid state on all end faces, or may be provided in a solid state on at least the end face on the side where the diffracted light travels. In the illustrated example, the light-absorbing layer 51 is provided on all end faces of the first light-transmitting plate 41.

[0036] Furthermore, a light absorbing layer 53 is also provided on the first surface of the first light-transmitting plate 41 . A region of the first surface of the first light-transmitting plate 41 that is irradiated with coherent light to record a replica hologram in the photosensitive layer 11 and has approximately the same shape and size as the master hologram 31 in a planar view is called a "corresponding region," while other regions of the first surface of the first light-transmitting plate 41 are called "non-corresponding regions." To expose the photosensitive layer 11 to form interference fringes of the master hologram 31 in the photosensitive layer 11, the corresponding region is irradiated with coherent light that is the same shape and size as the master hologram 31 or smaller than the master hologram 31. Therefore, when coherent light is incident from at least within the corresponding region, the coherent light is incident on the master hologram 31 from the corresponding region, thereby forming a replica hologram in the photosensitive layer 11. In FIGS. 6 and 7, the corresponding region is indicated by a fine dashed line (the corresponding region is the area surrounded by the fine dashed line). It should be noted that such broken lines are not actually drawn on the first light-transmitting plate 41.

[0037] The light-absorbing layer 53 is provided in the non-corresponding region of the first surface of the first light-transmitting plate 41. The light-absorbing layer 53 may be provided in a solid form over the entire non-corresponding region of the first surface (not shown), or may be provided at least in the non-corresponding region (first surface) on the side where the diffracted light travels. In the illustrated example, the light-absorbing layer 53 is provided not over the entire non-corresponding region, but in the non-corresponding region on the side where the diffracted light travels. In other words, the light-absorbing layer 53 is provided in a part of the non-corresponding region. Furthermore, an edge 53a of the light-absorbing layer 53 provided on the first surface is located along or near the edge of the corresponding region.

[0038] The material for forming the light-absorbing layers 51 and 53 is not particularly limited, provided that it contains an absorbent capable of absorbing the diffracted light. The light-absorbing layers 51 and 53 can be formed, for example, from the materials exemplified for the master light-absorbing layer 35. To avoid redundancy, further description will be omitted; for the materials and methods for forming the light-absorbing layers 51 and 53, please refer to the master light-absorbing layer 35.

[0039] 1 to 4 and 6, the first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43 are attached to a plate mounting member 48 with their longitudinal end faces in close contact with each other. Both ends in the width direction of each of the first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43 are attached to the plate mounting member 48. The plate mounting member 48 is fixed to a frame (not shown) of the manufacturing apparatus A. Note that the plate mounting member 48 may be provided with a movement mechanism (not shown) so that the first light-transmitting plate 41 and the like can be moved.

[0040] The light-absorbing layers 51 and 53 are provided to absorb the diffracted light before it is reflected. The purpose of providing the light-absorbing layers 51 and 53 will now be explained. As shown in FIG. 20 , laser light incident from the glass plate side passes through the photosensitive layer and enters the master hologram. The master hologram then generates diffracted light, which then passes through the photosensitive layer. The laser light and diffracted light pass through the photosensitive layer from two directions, exposing the photosensitive layer to light, forming a duplicate hologram in that area. However, the diffracted light that passes through the photosensitive layer may be internally reflected at the air interface of the glass plate (the bottom surface in the illustrated example), and the reflected light (reflected diffracted light) may pass through the duplicate hologram again. If the reflected light passes through again, the interference fringes of the duplicate hologram will be disrupted, making it impossible to produce a duplicate hologram with interference fringes similar to those of the master hologram. Therefore, in this embodiment, light-absorbing layers are provided to absorb the diffracted light before it is reflected.

[0041] For this purpose, light-absorbing layers 51, 53 may be provided in an appropriate area on the first surface and / or end surface of the light-transmitting plate, taking into consideration the dimensions of the coherent light, the diffraction angle of the diffracted light, the thickness of the light-transmitting plate (such as the first light-transmitting plate 41), etc. For example, as described above, when the light-absorbing layer 53 is provided on the first surface of the light-transmitting plate (such as the first light-transmitting plate 41) so that the edge 53a of the light-absorbing layer 53 is positioned along or near the edge of the corresponding region, by satisfying the relationship of the following formula (1), almost all of the diffracted light can be absorbed by the light-absorbing layers 51, 53 without being internally reflected. Equation (1): h>d / tanθ where h represents the thickness of the light-transmitting plate, d represents the dimension at the incident position of the coherent light, and θ represents the diffraction angle of the diffracted light. In formula (1), d refers to the dimension of the coherent light itself when the dimension of the coherent light at the incident position of the coherent light is equal to or smaller than the dimension of a master hologram, and refers to the dimension of the master hologram when the dimension of the coherent light is larger than the dimension of one master hologram. The diffraction angle of the diffracted light refers to the angle between the normal to the first surface of the master hologram and the propagation direction of the diffracted light.

[0042] Figure 8 is a reference side view showing the state of diffracted light when the relationship of formula (1) is satisfied. In this specification, a "reference side view" refers to a view seen from the side, with the internal components also shown in perspective. In Figure 8, coherent light L1 is shown by a solid line, and diffracted light L2 is shown by a dashed line.

[0043] 8, diffracted light L2 generated from master hologram 31 by irradiation with coherent light L1 is almost entirely absorbed by light absorption layers 51 and 53. This makes it possible to create a replica hologram in photosensitive layer 11 that has interference fringes similar to those of master hologram 31. Specifically, light-absorbing layers 51, 53 are provided on the end faces and first faces of the first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43. Therefore, as shown in FIG. 8, coherent light L1 incident from the corresponding region on the first face of the first light-transmitting plate 41 is diffracted at a predetermined diffraction angle (e.g., an acute diffraction angle) recorded in the master hologram 31 of the first row S-1, generating diffracted light L2. When the diffracted light L2 first strikes the first face and end faces of the first light-transmitting plate 41, the diffracted light is absorbed by the light-absorbing layers 51, 53 without being internally reflected. Therefore, it is possible to prevent reflected light (diffracted light reflected by the first face and end faces of the first light-transmitting plate 41) from re-entering the duplicate hologram 310 formed by exposing the photosensitive layer 11 as the coherent light L1 and diffracted light L2 pass through the photosensitive layer 11. Therefore, the interference fringes of the replica hologram 310 are not disturbed, and it is possible to produce a replica hologram 310 having interference fringes similar to those of the master hologram 31. As with the first light-transmitting plate 41, the second and third light-transmitting plates 42 and 43 also absorb the diffracted light in the light-absorbing layers 51 and 53 without being internally reflected.

[0044] Furthermore, the light-transmitting plates are divided into a plurality of pieces corresponding to the rows, such as a first light-transmitting plate 41, a second light-transmitting plate 42, and a third light-transmitting plate 43, and a light-absorbing layer 51 is provided on at least the end face of each plate on the side on which the diffracted light travels. Therefore, the diffracted light traveling through one light-transmitting plate does not enter the light-transmitting plate adjacent to the light-transmitting plate in the transport direction. In other words, because the light-transmitting plates are divided into a plurality of pieces and the light-absorbing layer 51 is provided on the end face on the side on which the diffracted light travels, for example, the diffracted light L2 traveling through the second light-transmitting plate 42 does not enter the first light-transmitting plate 41 adjacent to the second light-transmitting plate 42, and the diffracted light L2 traveling through the third light-transmitting plate 43 does not enter the second light-transmitting plate 42 adjacent to the third light-transmitting plate 43. This prevents, for example, diffracted light L2 generated in the master hologram 31 in the second row S-2 from entering the first light-transmitting plate 41, causing the diffracted light L2 to be internally reflected and enter the duplicate hologram 310 in the first row S-1, thereby disrupting the interference fringes of the duplicate hologram 310. The first row S-1 and the second row S-2, and the second row S-2 and the third row S-3, are adjacent rows in the transport direction.

[0045] Furthermore, even when the relationship of the following formula (2) is satisfied, it is possible to prevent reflected light from being incident on the duplicate hologram again. Equation (2): h>d / 2tanθ Here, h, d, and θ are the same as in equation (1).

[0046] Figure 9 is a reference side view showing the state of diffracted light when the relationship of formula (2) is satisfied. Coherent light is shown by a solid line, diffracted light by a dashed line, and reflected light by a dot-dash line. 9, diffracted light L2 generated from the master hologram 31 by irradiation with coherent light L1 is partially absorbed by the light-absorbing layers 51 and 53, but part of the diffracted light L2 is internally reflected (generating reflected light L3) at the air interface in the corresponding region of the first light-transmitting plate 41. If the relationship of formula (2) is satisfied, the reflected light L3 is less likely to enter the replica hologram. Specifically, as shown in FIG. 9 , a portion of the diffracted light L2 is absorbed by the light-absorbing layers 51, 53 provided on the first surface and end surface of the first light-transmitting plate 41 and is not reflected. A portion of the diffracted light L2 travels to a corresponding region on the first surface of the first light-transmitting plate 41 and is internally reflected there, and reflected light L3 travels back into the first light-transmitting plate 41. When the relationship of formula (2) is satisfied, the reflected light L3 is unlikely to be incident on the duplicate hologram 310 formed in the photosensitive layer 11 and instead travels to the master layer 3. Note that, because the master light-absorbing layer 35 is provided on the second surface of the master layer 3, the reflected light L3 that has passed through the master layer 3 is absorbed by the master light-absorbing layer 35. This prevents the reflected light L3 from repeatedly reflecting and entering the duplicate hologram 310. Even when the relationship of formula (2) is satisfied, the interference fringes of the replica hologram 310 are not disturbed by the reflected light, and it is possible to produce a replica hologram 310 having interference fringes similar to those of the master hologram 31. The second light-transmitting plate 42 and the third light-transmitting plate 43 are similar to the first light-transmitting plate 41.

[0047] Note that neither Equation (1) nor Equation (2) takes into account the thickness of the material to be treated 1. In other words, in Equation (1) and Equation (2), it would be more accurate to define h as "the thickness of the light-transmitting plate + the thickness of the material to be treated 1." However, the thickness of the material to be treated 1 (the thickness of the photosensitive layer 11 and the thickness of the supporting substrate 12) is much smaller than the thickness of the light-transmitting plate. Therefore, even without taking the thickness of the material to be treated 1 into consideration, it is believed that the above-mentioned effects can be achieved by satisfying the relationship between Equation (1) and Equation (2). Note that in each figure, the thickness of the material to be treated 1 (the photosensitive layer 11 and the supporting substrate 12) is exaggerated to make the material to be treated 1 easier to understand. For this reason, h is defined as "the thickness of the light-transmitting plate," but if necessary, h in formulas (1) and (2) may be defined as "the thickness of the light-transmitting plate + the thickness of the material to be treated."

[0048] (others) The exposure section C is provided with a pressure roll 28 for bringing the material 1 into close contact with the light-transmitting plate. The exposure section C also has an index oil injector and an index oil remover (neither of which are shown) that are interposed between the master layer 3 and the material 1 to prevent an air interface from occurring between the master layer 3 and the material 1. 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 exposure-processed 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.

[0049] <Light source> 1 and 3, a light source D irradiates a stack including a photosensitive layer 11 with coherent light L11 in an exposure section C. The light source D irradiates all master holograms 31 of the master layer 3 with the coherent light L11 simultaneously.

[0050] 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.

[0051] The light source D includes a laser oscillator 61, a reflector 62 that changes the direction of laser light from the laser oscillator 61 and causes the laser light to travel toward a laminate including a photosensitive layer 11, and various optical devices arranged between the laser oscillator 61 and the reflector 62.

[0052] 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.

[0053] In the illustrated example, the light source D has three laser oscillators 61 (a first oscillator 611, a second oscillator 612, and a third oscillator 613) that each emit coherent light of a different wavelength. For example, the first oscillator 611 is a red laser oscillator, the second oscillator 612 is a green laser oscillator, and the third oscillator 613 is a blue laser oscillator. The number of laser oscillators 61 provided in the light source D is not limited to three, and may be one, two, or four or more.

[0054] The reflector 62 is not particularly limited as long as it can reflect the laser beam, which is coherent light, and for example, a mirror can be used. Examples of optical devices include a shutter, a magnifying lens, a collimating lens, a half-wave plate, a dielectric multilayer mirror, an achromatic lens, a mask member, a beam splitter, etc., and these may be appropriately selected and arranged on the optical path. In order to simultaneously irradiate multiple master holograms 31 with coherent light, the laser light emitted from laser oscillator 61 is expanded and flattened.

[0055] 3 shows one example of the configuration of light source D. Arranged on the optical path of first oscillator 611 are, in this order, a shutter 6111, a dielectric multilayer mirror 6112, a magnifying lens 6113, a collimating lens 6114, a half-wave plate 6115, and a dielectric multilayer mirror 6116. The red laser light emitted from first oscillator 611 is magnified and flattened by magnifying lens 6113 and collimating lens 6114, has its polarization direction adjusted by half-wave plate 6115, and is then reflected by dielectric multilayer mirror 6116. The shutter is a device that controls the blocking and transmission of light, and the dielectric multilayer mirror is a device that reflects light of a specific wavelength with a high reflectance. On the optical path of second oscillator 612, there are arranged, in this order, a shutter 6121, a dielectric multilayer mirror 6122, a magnifying lens 6123, a collimating lens 6124, a half-wave plate 6125, and a dylomic mirror 6126. The green laser light emitted from second oscillator 612 is similarly magnified and flattened, and reflected by dylomic mirror 6126. Dylomic mirror 6126 is a mirror that selectively reflects light of a specific wavelength, and transmits red laser light and reflects green laser light. On the optical path of third oscillator 613, there are arranged, in this order, a shutter 6131, a dielectric multilayer mirror 6132, a magnifying lens 6133, a collimating lens 6134, a half-wave plate 6135, and a dylomic mirror 6136. The blue laser light emitted from third oscillator 613 is similarly magnified and flattened, and reflected by dylomic mirror 6136. Dylomic mirror 6136 is a mirror that selectively reflects light of a specific wavelength, and transmits red laser light and green laser light and reflects blue laser light.

[0056] Furthermore, the red, green, and blue laser beams travel the same optical path after the Dylomic mirror 6136. After the Dylomic mirror 6136, a shutter 71, a magnifying lens 72, a collimating lens 73, and a broadband dielectric multilayer mirror 74 are provided. The laser beams transmitted through or reflected by the Dylomic mirror 6136 are further expanded and collimated by the magnifying lens 72 and the collimating lens 73, and then reflected by the broadband dielectric multilayer mirror 74. After the broadband dielectric multilayer mirror 74, a magnifying lens 75, a collimating lens 76, and a mask member 77 are provided. The laser beams reflected by the broadband dielectric multilayer mirror 74 are further expanded and collimated by the magnifying lens 75 and the collimating lens 76, and then pass through the mask member 77, whereby they are shaped into the shape of an opening 771 in the mask member 77. The mask member 77 is a member that blocks a portion of the laser beam, which is coherent light, and shapes the coherent light into a desired shape (the shape of the opening 771). In other words, the mask member 77 is a member that trims the coherent light L12 emitted and expanded from the laser oscillator 61 and passes coherent light L11 of a desired shape. In this specification, the coherent light L11 after being trimmed into a desired shape by the mask member 77 is referred to as "trimmed light L11." In order to simultaneously irradiate all master holograms 31 in the master layer 3 with coherent light, the trimming light L11, in the illustrated example, is formed by a mask member 7 that trims the expanded coherent light L12 into a rectangular shape in plan view that encompasses all master holograms 31.

[0057] The trimming light L11 is irradiated onto the master hologram 31. The trimming light L11 when irradiated onto the master hologram 31 is represented by a fine dashed line on the master layer 3 in FIG. A reflector 62 is provided to direct the trimming light L11 toward the master hologram 31. In this embodiment, for example, one reflector 62 is provided. The reflector 62 changes the traveling direction of the trimming light L11 obtained from the oscillator through an optical device toward the master hologram 31. Although not specifically shown, the laser oscillator 61, magnifying lens, and other optical devices that constitute the light source D, as well as the reflector 62, are fixed to a stage table (not shown) or the like provided on the frame of the manufacturing device A.

[0058] {Hologram manufacturing method} Next, a method for manufacturing a hologram will be described. When a replica hologram is produced using the master hologram 31, the production apparatus A is used. As shown in FIG. 11 , the master layer 3 is separated from the support substrate 12 of the processed material 1 by the moving mechanism 382, ​​the transport unit B transports the processed material 1 downstream in the transport direction by a predetermined length, and the transport of the processed material 1 in the exposure unit C is stopped. This predetermined length corresponds to the portion of the photosensitive layer 11 that has been exposed. Next, the pressure roll 28 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 28 is indicated by a two-dot chain line). This causes the first surface of the photosensitive layer 11 of the processed material 1 to adhere to the second surface of the light-transmitting plate. Because the photosensitive layer 11 has slight adhesiveness, lightly pressing the processed material 1 with the pressure roll 28 allows the photosensitive layer 11 of the processed 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. Thereafter, as shown in FIG. 1, the master layer 3 is moved closer to the support substrate 12 of the processing target 1 by the movement mechanism 382.

[0059] There is a gap between the first surface of the master layer 3 and the support substrate 12 of the workpiece 1, and the presence of this gap creates an air interface. For this reason, an index oil injector (not shown) is used to inject and fill the gap between the first surface of the master layer 3 and the support substrate 12 of the workpiece 1. Figure 4 shows the state after index oil 39 has been injected. Index oil 39 is an oil with a refractive index approximately equal to that of the light-transmitting plate. In this way, a laminate consisting of master layer 3 / index oil 39 / processed material 1 (support substrate 12 + photosensitive layer 11) / transparent plates 41, 42, 43, with no air interface between each layer, is temporarily formed in the exposure section C.

[0060] As shown in Figures 1 and 3, trimming light L11 (coherent light) is irradiated onto all master holograms 31 from the first surface side of the light-transmitting plate 41 of this laminate, exposing the photosensitive layer 11 and creating a replica hologram in the photosensitive layer 11 that has interference fringes similar to those of the master hologram 31. The irradiation time of the trimming light L11 is until exposure of the photosensitive layer 11 is complete for all master holograms 31. The irradiation time is appropriately set taking into consideration the output of the laser light from the oscillator, the magnification of the laser light, the size of the trimming light, and the like. Specifically, the energy intensity of the laser light is high at the center and decreases the further away from the center. Therefore, the intensity of the trimming light at the edges is lower than that at the center. The irradiation time is set taking into consideration the cumulative exposure amount so that the photosensitive layer 11 can be sufficiently exposed near the edges of the trimming light L11 and the photosensitive layer 11 is not overexposed near the center of the trimming light L11. As described below, a replica hologram can be efficiently produced when the ratio of the intensity of the edge of the trimming light to the intensity of the center of the trimming light is 20% to 80%, or when the ratio of the effective area of ​​the trimming light to the area of ​​the expanded laser light immediately before passing through the mask member is 5% to 60%. The effective area of ​​the trimming light refers to an area of ​​the trimming light that can make coherent light incident on a plurality of master holograms 31 simultaneously.

[0061] The coherent light 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. For example, when shutter 6111 of first oscillator 611 is opened and shutters 6121 and 6131 of second oscillator 612 and third oscillator 613 are closed, red laser light from first oscillator 611 is reflected by each reflector 62 and irradiates all master holograms 31. In this case, a red replica hologram is created in photosensitive layer 11. When shutter 6121 of second oscillator 612 is opened and shutters 6111 and 6131 of first oscillator 611 and third oscillator 613 are closed, green laser light from second oscillator 612 is reflected by each reflector 62 and irradiates all master holograms 31. In this case, a green replica hologram is created in photosensitive layer 11. When the shutter 6131 of the third oscillator 613 is opened and the shutters 6111 and 6121 of the first and second oscillators 611 and 612 are closed, the blue laser light from the third oscillator 613 is reflected by each reflector 62 and irradiated onto all of the master holograms 31. In this case, a blue replica hologram is created in the photosensitive layer 11. 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.

[0062] Trimming light L11 (coherent light) irradiated from the first surface side of the light-transmitting plate enters the light-transmitting plate from a corresponding region of the light-transmitting plate (such as first light-transmitting plate 41), passes through photosensitive layer 11, and then enters master hologram 31 to generate diffracted light. The diffracted light passes through photosensitive layer 11, exposing photosensitive layer 11. In other words, the 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 a replicated hologram. Note that the trimming light L11 has a rectangular shape in a plan view that encompasses all of the master holograms 31, and therefore includes portions that extend beyond the corresponding regions of each master hologram 31. The light of the trimming light L11 that extends beyond the corresponding regions does not enter the master holograms 31 and does not produce diffracted light. As a result, interference fringes are not recorded in the photosensitive layer 11 through which the extending light passes. Alternatively, the extending light is absorbed by the light absorption layer 53 and the master light absorption layer 35, and therefore interference fringes are not recorded in the photosensitive layer 11. Therefore, by simultaneously irradiating all of the master holograms 31 with the trimming light L11, the same number of replica holograms with approximately the same shape and size as each master hologram 31 are created in the photosensitive layer 11.

[0063] As described above, providing the light-absorbing layers 51, 53 on the light-transmitting plate prevents reflected diffracted light from entering the duplicate hologram, thereby ensuring the production of a duplicate hologram having interference fringes similar to those of the master hologram 31. In particular, by dividing the light-transmitting plate into multiple pieces and providing the light-absorbing layers 51, 53 on at least the end face of each light-transmitting plate on the side along which the diffracted light travels, the diffracted light can also be prevented from entering duplicate holograms adjacent to each other in the transport direction.

[0064] After the trimming light L11 has been irradiated in this manner to form replica holograms corresponding to all of the master holograms 31 in the photosensitive layer 11, the irradiation of the trimming light L11 from the light source D is stopped. For example, the shutter 71 is closed or the laser oscillator 61 is stopped from emitting light to prevent the coherent light from traveling to the reflector 62. Next, the moving mechanism 382 separates the master layer 3 from the support substrate 12 of the workpiece 1. After the master layer 3 has been separated, index oil is usually attached to the second surface of the support substrate 12 of the workpiece 1, so the index oil attached to the support substrate 12 is removed by wiping it off using an index oil remover (not shown).

[0065] The material 1 is then transported downstream in the transport direction by a predetermined length (the length that has been exposed), and the transport is stopped. The material 1 is adhered to the second surfaces of the light-transmitting plates 41, 42, and 43 due to the slight adhesiveness of the photosensitive layer 11. Because the slight adhesiveness of the photosensitive layer 11 is very weak, the material 1 separates from the light-transmitting plates 41, 42, and 43 when the transport unit B pulls the material 1. However, if the photosensitive layer 11 is difficult to separate from the light-transmitting plates 41, 42, and 43, an appropriate peeling means may be provided in the transport unit B, or the light-transmitting plates 41, 42, and 43 may be moved away from the material 1 (not shown).

[0066] The exposed material 1 is transported and stopped, returning to the state shown in FIG. 11. This sends the exposed photosensitive layer 11 downstream, and the unexposed photosensitive layer 11 is subsequently placed in the exposure section C. Thereafter, in a similar manner, the master layer 3 is brought into close contact with the material 1 and exposed to trimming light L11 to create duplicate holograms in the photosensitive layer 11 corresponding to all of the master holograms 31. The master layer 3 is then released, the material 1 is transported a predetermined length, and the process is then stopped. This process is repeated. In this manner, duplicate holograms can be created efficiently and continuously. According to the present invention, all master holograms 31 in the master layer 3 are simultaneously irradiated with coherent light, making it possible to create multiple replica holograms in the photosensitive layer 11, the same number as the master holograms 31. In conventional methods, when creating a replica hologram by irradiating a single master hologram with laser light, a repeating process is required: laser light irradiation, moving the master hologram, transporting the photosensitive layer, and then adhering the master hologram. Conventionally, only one replica hologram could be created per repeating process, and creating multiple replica holograms required a relatively long time. In contrast, according to the present invention, multiple master holograms 31 are simultaneously irradiated with coherent light, making it possible to simultaneously create multiple replica holograms. This allows multiple replica holograms to be created per repeating process: coherent light irradiation, moving the master layer, transporting the photosensitive layer, and adhering the master layer, thereby enabling efficient production of replica holograms.

[0067] Figure 12(a) is a plan view of an exposed material 100. The exposed material 1 has a plurality of replicated holograms arranged continuously in its photosensitive layer 11. Hereinafter, the "exposed material 100" will be referred to as the "replica hologram continuum 100." The above example illustrates the use of three rows of master holograms 31, so the replicate hologram continuum 100 in Figure 12 has a plurality of replicated holograms 310 arranged in three rows.

[0068] As shown in Figure 1, a bleaching treatment is performed on a replica hologram continuum 100 in a bleaching unit 29. A protective film 15 and a release liner 16 are laminated to the bleached replica hologram continuum 100 in a film laminating unit 25 and a liner laminating unit 26, respectively, and the resulting product is then wound up in a winding unit 27.

[0069] If necessary, the replicate hologram continuum 100 may be divided into individual rows of replicate holograms, and then the individual rows may be wound up on the winding section 27. For example, as shown in Figure 12(b), a multi-row replicate hologram continuum 100 may be divided into single-row replicate hologram continuums 100 using a slitter 290, and then these may be wound up individually. It is generally preferable that the division by the slitter 290 be carried out after the protective films 15 and release liners 16 have been attached to each other.

[0070] <Uses of replicated holograms> By cutting the replicated hologram continuum 100 at appropriate points, individual replicated holograms can be obtained. The use of the replica hologram is not particularly limited. The replica hologram of the present invention can be applied to various applications that have been known in the past or will become known in the future. For example, the replica hologram can be used 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 manufactured by sandwiching a replica hologram between two glass plates or transparent resin plates. Furthermore, a light guide plate for an AR device can be manufactured using the replica hologram. An AR (Augmented Reality) device is a device, such as smart glasses, that can simultaneously project text information and virtual content in addition to 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.

[0071] 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 Figure 13, a light guide plate G for an AR device can be constructed by stacking a red duplicate hologram 310R consisting of incouplings 311R and outcouplings 312R, a green duplicate hologram 310G consisting of incouplings 311G and outcouplings 312G, and a blue duplicate hologram 310B consisting of incouplings 311B and outcouplings 312B in that order, and then laminating glass plates or transparent resin plates on the front and back of the stack.

[0072] The second embodiment will be described below, and in this description, the configuration and effects that differ from those of the above-mentioned embodiment will be mainly described. For similar configurations, the terms or symbols will be used as they are, and the description of the configuration may be omitted (the same applies to the third embodiment and beyond).

[0073] [Second embodiment] In the first embodiment, the trimming light L11 is shaped into a substantially rectangular shape that encompasses all of the master holograms 31. However, as shown in FIG. 14, for example, coherent light L12 emitted from a laser oscillator 61 and expanded and flattened may be trimmed into the same number of trimming light beams L111 as the number of master holograms 31. In FIG. 14, a mask member 77 is provided with the same number of openings 772 as the number of master holograms 31, and the expanded and flattened coherent light L12 that passes through the mask member 77 is split into the same number of trimming light beams L111 as the number of master holograms 31 and into trimming light beams L111 that have substantially the same shape as the master holograms 31 in a planar view. The trimming light L111 when irradiated onto the master holograms 31 is represented by a fine dashed line on the master layer 3 in FIG. In the above, the coherent light L12 emitted from the laser oscillator 61 and expanded and flattened is trimmed by the mask member 77, but it is also possible to irradiate all of the master holograms 31 with approximately circular coherent light L12 (without providing the mask member 77) (not shown). Furthermore, in the above, the mask member 77 is disposed between the laser oscillator 61 and the reflector 62, but the mask member 77 may be disposed between the reflector 62 and the photosensitive layer 11 (not shown).

[0074] [Third embodiment] In the first embodiment described above, the longitudinal end faces of multiple light-transmitting plates (e.g., the first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43) are in close contact with each other, but there may be gaps between adjacent multiple light-transmitting plates (e.g., the first light-transmitting plate 41, the second light-transmitting plate 42, and the third light-transmitting plate 43), as shown in, for example, FIG. 15.

[0075] Although the first embodiment uses multiple separated light-transmitting plates, a single light-transmitting plate 44 may be used, as shown in FIG. 16 . That is, a single light-transmitting plate 44 corresponding to all of the master holograms 31 may be disposed on the first surface side of the master layer 3. When a single light-transmitting plate 44 corresponding to all of the master holograms 31 is used, a light-absorbing layer 53 is provided in at least the non-corresponding area of ​​the first surface of the light-transmitting plate 44, and preferably, a light-absorbing layer 51 is also provided on the end surface of the light-transmitting plate 44. As shown in FIG. 15 , the light-absorbing layer 53 provided on the first surface of the light-transmitting plate 44 preferably has a dimension equal to or greater than the dimension d of the coherent light. This allows the diffracted light L2 to be absorbed by the light-absorbing layer 53. In this embodiment, one light-transmitting plate 44 is provided for each hologram, and a light-absorbing layer 53 having a dimension equal to or greater than the dimension d of the coherent light is provided on the first surface of the light-transmitting plate 44. This prevents the diffracted light L2 from being internally reflected by the first surface. However, in this embodiment, the distance between adjacent master holograms 31 in the transport direction (for example, the master hologram 31 in the first row S-1 and the master hologram 31 in the second row S-2, or the master hologram 31 in the second row S-2 and the master hologram 31 in the third row S-3) must be relatively large. In this regard, by using light-transmitting plates 41, 42, and 43 separated by rows and provided with light-absorbing layers 51 on their end surfaces, as in the first embodiment, the diffracted light L2 can be absorbed by the light-absorbing layers 51 and 53 even if the distance between adjacent master holograms 31 in the transport direction is relatively small. Therefore, by using light-transmitting plates 41, 42, and 43 that are divided into multiple pieces and provided with a light-absorbing layer 51 as in the first embodiment, the distance between adjacent master holograms 31 can be reduced, which has the advantage of allowing more replica holograms to be produced per unit length of the processed material 1.

[0076] [Fourth embodiment] In the first embodiment, the photosensitive layer 11 of the material to be processed 1 is brought into close contact with the light-transmitting plates 41, 42, and 43 in the exposure section C, but as shown in Fig. 17, the material to be processed 1 may be turned over so that the photosensitive layer 11 of the material to be processed 1 is brought into close contact with the master layer 3. In this case, an air interface is created between the support substrate 12 of the material to be processed 1 and the second surface of the light-transmitting plate, and index oil 39 may be filled between them.

[0077] [Fifth embodiment] In the first embodiment, coherent light is irradiated from the lower side of the page in the exposure unit C, but coherent light may be irradiated from the upper side of the page (not shown). In this case, the configuration of the exposure unit C in the first embodiment is inverted upside down so that coherent light can be irradiated from the lower side of the page. In the first embodiment, the coherent light is irradiated parallel to the normal direction of the master hologram 31, and the diffracted light travels at an acute diffraction angle, but the present invention is not limited to this. The coherent light is irradiated at an angle that reproduces the master hologram 31. Furthermore, in the first embodiment described above, coherent light is irradiated onto the workpiece 1 in an approximately horizontal position at the exposure section C, but coherent light may also be irradiated onto the workpiece 1 in an oblique or vertical position (not shown), for example. Furthermore, the present invention is not limited to the various embodiments described above, and can be modified as appropriate within the intended scope of the present invention. [Example]

[0078] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0079] [Example 1] <Preparing the material to be treated> A photopolymer was applied to a triacetyl cellulose film to prepare a processing target material in which a photosensitive layer having a thickness of 16 μm was formed on a supporting substrate. <Preparing the Master Layer> As shown in Figure 18(a), one master hologram 31-E is provided within a square frame 81-E measuring 50 mm x 50 mm, which constitutes one unit of master hologram. As shown in the figure, the master hologram 31-E is a square that is slightly smaller than the frame 81-E indicated by the dashed line. Note that the frame 81-E indicated by the dashed line in Figure 18 is shown merely for the sake of convenience, and that the frame 81-E does not actually exist. The master layer in Example 1 was one in which one unit of the master hologram was arranged in 6 rows and 6 columns, as shown in FIG.

[0080] <Exposure> The master layer containing the 6-row x 6-column master hologram, the substrate, and a 30 mm-thick glass plate were bonded together via index oil to form a laminate consisting of master layer / index oil / support substrate / photosensitive layer / glass plate. The photosensitive layer was exposed by simultaneously irradiating all master holograms with trimming light for a predetermined period of time from the glass plate side of this laminate. This exposure produced 36 duplicate holograms in the photosensitive layer, the same number as the master holograms. The trimming light was obtained by expanding and collimating the laser light emitted from a 532 nm laser oscillator (manufactured by Cobolt under the trade name "Cobolt 05-01 Series Samba") in stages multiple times, and then passing the expanded and collimated laser light through a mask member. FIG. 19 shows the shapes of the expanded and collimated laser beam L12-E and the trimming beam L11-E immediately before passing through the mask member. Hereinafter, the expanded and collimated laser beam immediately before passing through the mask member will be referred to as the "expanded laser beam." The expanded laser beam L12-E was circular with a diameter D1-E, and the trimming beam L11-E was square with a side 82-E. The center O of the expanded laser beam L12-E and the center O of the trimming beam L11-E are aligned. The circle L13-E, represented by a fine dashed line, is a circle that passes through the four corners 83-E of the trimming beam L11-E. <Exposure conditions> Oscillator power: 500mW. Diameter of laser beam before expansion: 3mm. Laser beam magnification: 327 times. Diameter D1-E of expanded laser beam L12-E: 980 mm. Trimming light L11-E, one side 82-E:300mm. Irradiation time (exposure time): 115 seconds. The irradiation time is set so that the cumulative exposure of the trimming light L11-E at the corner 83-E is 20 mJ / cm 2 This is the time required for the cumulative exposure dose to reach 20 mJ / cm 2 It has been empirically found that if the above conditions are met, the photosensitive layer can be exposed sufficiently and a good hologram replica can be produced.

[0081] [Table 1]

[0082] [Examples 2 to 6] The photosensitive layers were exposed by simultaneously irradiating all master holograms with trimming light for a predetermined period of time in the same manner as in Example 1, except that the arrangement of the master holograms and the exposure conditions were changed as shown in Table 1. In each of Examples 2 to 6, nine duplicate holograms were produced.

[0083] In Table 1, "Effective Area of ​​Trimming Light / Area of ​​Magnified Laser Light (%)" refers to the ratio of the effective area of ​​the trimming light to the area of ​​the laser light (coherent light) immediately before passing through the mask member. The effective area of ​​the trimming light is the area of ​​the trimming light that allows coherent light to be incident simultaneously on multiple master holograms 31. When multiple master hologram units are arranged vertically and horizontally, as in this embodiment, the effective area of ​​the trimming light is the area enclosed by lines connecting the outer edges of the outermost master holograms. In this embodiment, the area of ​​the trimming light and the area enclosed by lines connecting the outer edges of the outermost master holograms are substantially the same. For example, trimming light having the shape of a circle L13-E, represented by a fine dashed line in FIG. 19, can also be used as the trimming light. When using the circular trimming light L13-E or the rectangular trimming light L11-E, all master holograms can be irradiated simultaneously, and the cumulative exposure dose remains the same. That is, the effective area of ​​the circular trimming light L13-E is the same as the effective area of ​​the rectangular trimming light L11-E (the area of ​​the range enclosed by the lines connecting the outer edges of the outermost master holograms).

[0084] In Table 1, "energy intensity at corners / energy intensity at center (%)" is the ratio of the intensity at the edge (corner) of the trimming light to the intensity at the center of the trimming light. The intensity ratio and the energy intensities at the center and corners of the trimming light were calculated by measuring the energy intensity at the center and assuming that the energy intensity of the laser light follows a Gaussian distribution. The energy intensity and intensity ratio at the corners were calculated from the energy intensity at the center. The energy intensity values ​​for the center and corners in Table 1 are measured and calculated values ​​rounded to one decimal place. On the other hand, the corner energy intensity / center energy intensity values ​​in Table 1 are unrounded values ​​(measured and calculated values). Therefore, please note that the value obtained by simply dividing the center and corner strength values ​​in Table 1 does not match the energy intensity / center energy intensity value in Table 1.

[0085] [evaluation] The "irradiation time per replicated hologram" in Table 1 was calculated from the irradiation time of the trimming light / the number of replicated holograms obtained. All of the replicated holograms obtained in Examples 1 to 6 had good interference fringes. Specifically, of the 36 replicated holograms obtained in Example 1, both the central replicated hologram (created by irradiating the trimming light near the center) and the corner replicated holograms (created by irradiating the trimming light near the corners) had good interference fringes. The same was true for Examples 2 to 6.

[0086] As shown in Table 1, Examples 1 and 3 to 5 require less time to produce one duplicate hologram than Examples 2 and 6. Therefore, when producing the same number of duplicate holograms, Examples 1 and 3 to 5 complete the work in a shorter time than Examples 2 and 6. Comparing Examples 1 and 3 to 5 with Examples 2 and 6, it is found that the time required to produce one duplicate hologram can be shortened by setting the ratio of the effective area of ​​the trimming light to the area of ​​the magnified laser light immediately before passing through the mask member to within the range of 5% to 60%, preferably within the range of 7% to 50%, and more preferably within the range of 10% to 40%. Furthermore, by setting the ratio of the energy intensity of the edge of the trimming light to the energy intensity of the center of the trimming light to within the range of 20% to 80%, preferably within the range of 25% to 75%, and more preferably within the range of 30% to 71%, the time required to produce one replica hologram can be shortened. [Explanation of symbols]

[0087] A Hologram manufacturing equipment B. Manufacturing equipment conveying section C. Exposure section of manufacturing equipment D Light source for manufacturing equipment L1 Coherent light L2 diffracted light L11, L111 trimming light L12 Coherent light just before trimming 11 Photosensitive layer 3 Master Tier 31 Master Hologram 41,42,43 Transparent plate 51,53 Light absorbing layer 61 Laser oscillator 613 Third Oscillator 62 Reflector 77 Mask material

Claims

1. an exposure section having a master layer having a master hologram; a transport section that transports an unexposed photosensitive layer and positions the photosensitive layer on the first surface side of the master layer in the exposed section; a light source that irradiates the master hologram with coherent light from the first surface side of the photosensitive layer, an apparatus for duplicating interference fringes of the master hologram on the photosensitive layer by transmitting the coherent light and diffracted light generated from the master hologram by irradiation of the coherent light through the photosensitive layer to expose the layer, the apparatus comprising: the master layer has a plurality of master holograms; A hologram manufacturing apparatus, wherein the light source irradiates all of the master holograms in the master layer simultaneously with coherent light.

2. the photosensitive layer is in the form of a long strip, the plurality of master holograms are arranged in a plurality of columns in a width direction of the photosensitive layer and in a plurality of rows in a transport direction that is a direction perpendicular to the width direction, 2. The hologram manufacturing apparatus according to claim 1, wherein the transport unit transports the long strip-shaped photosensitive layer by a predetermined length in the longitudinal direction and then stops transporting the photosensitive layer.

3. the light source has a mask member that trims the expanded and flattened coherent light; The trimming light that has passed through the mask member and been trimmed is simultaneously irradiated onto all the master holograms of the master layer, 2. The hologram manufacturing apparatus according to claim 1, wherein a ratio of the intensity of the trimming light at the edge to the intensity of the trimming light at the center is 20% to 80%.

4. the light source has a mask member that trims the expanded and flattened coherent light; The trimming light that has passed through the mask member and been trimmed is simultaneously irradiated onto all the master holograms of the master layer, 2. The hologram manufacturing apparatus according to claim 1, wherein a ratio of an effective area of ​​the trimming light to an area of ​​the coherent light immediately before passing through the mask member is 5% to 60%.

5. the light source further comprises an oscillator of the coherent light and a reflector that changes the direction of the light toward the master hologram; 5. The hologram manufacturing apparatus according to claim 3, wherein the mask member is disposed between the oscillator and the reflector or between the reflector and the photosensitive layer.

6. a transport step of transporting an unexposed photosensitive layer to a first surface side of a master layer having a master hologram; an exposure step of irradiating the photosensitive layer with coherent light from the first surface side of the photosensitive layer after disposing the photosensitive layer on the first surface side of the master layer, a method for duplicating interference fringes of the master hologram onto a photosensitive layer by transmitting the coherent light and diffracted light generated from the master hologram by irradiation of the coherent light through the photosensitive layer, the method comprising: the master layer has a plurality of master holograms; a hologram manufacturing method in which, in the exposure step, the coherent light is irradiated simultaneously onto all of the master holograms in the master layer;

7. trimming the expanded and flattened coherent light by passing it through a mask member, and simultaneously irradiating all the master holograms of the master layer with the trimmed light that has passed through the mask member; 7. The method for producing a hologram according to claim 6, wherein a ratio of the intensity of the edge of the trimming light to the intensity of the center of the trimming light is 20% to 80%.

8. trimming the expanded and flattened coherent light by passing it through a mask member, and simultaneously irradiating all the master holograms of the master layer with the trimmed light that has passed through the mask member; 7. The method for producing a hologram according to claim 6, wherein a ratio of an effective area of ​​the trimming light to an area of ​​the coherent light immediately before passing through the mask member is 5% to 60%.

9. A light guide plate having a hologram manufactured by the manufacturing method according to any one of claims 6 to 8.

10. A light guide plate having a hologram manufactured by the manufacturing apparatus according to any one of claims 1 to 5.

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