Method for manufacturing laminated holographic element

Abstract

The present disclosure provides a method capable of manufacturing a laminated holographic element in which holographic layers of RGB colors are aligned with high accuracy. The laminated holographic element (100) manufactured by the present invention has a structure in which a red holographic layer (20), a green holographic layer (30), and a blue holographic layer (40), which are generated by irradiating a photosensitive material (10) with light of each of RGB colors from two directions (an alpha direction, a beta direction) that are different from each other, are laminated. In the present invention, first to third captured images are acquired by irradiating each holographic layer with a red first illumination light, a green second illumination light, and a blue third illumination light from the vicinity of the alpha direction, and imaging each holographic layer from the beta direction. Coordinates of corners and the like of each holographic layer are detected by performing image processing on each of the first to third captured images. The position of each holographic layer is adjusted so that the coordinates of the corners and the like of at least two locations of the holographic layer of each color coincide, and the holographic layers after the position adjustment are bonded.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a laminated hologram element by laminating a red hologram layer, a green hologram layer, and a blue hologram layer. In particular, the present invention relates to a method for manufacturing a laminated hologram element in which the red hologram layer, the green hologram layer, and the blue hologram layer are aligned with high precision. Background Art

[0002] Conventionally, a method of manufacturing a laminated hologram element by laminating a red hologram layer, a green hologram layer, and a blue hologram layer has been proposed (for example, see Patent Documents 1 and 2).

[0003] For example, when the stacked hologram element is used as a light guide plate, if the positions of the hologram layers are shifted, the guiding directions of red, green, and blue wavelengths of light will shift, causing a problem of reduced color reproducibility.

[0004] Therefore, the manufacturing method described in Patent Document 1 proposes recording alignment marks in each holographic layer using a holographic method. However, this method has the problem of marks remaining in each holographic layer.

[0005] Furthermore, the manufacturing method described in Patent Document 2 proposes providing alignment marks on the exterior of each holographic layer for positioning. However, this method does not provide alignment marks on each holographic layer itself, but rather provides alignment marks on the exterior of the holographic layer (the portion of the photopolymer where the holographic layer is not formed) for position adjustment. Consequently, there is a problem in that the position of each holographic layer itself cannot be adjusted with sufficient accuracy.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 11-272153

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2015-175967 Summary of the Invention

[0010] The present invention is made to solve the above-mentioned problems of the prior art, and its technical problem is to provide a method for manufacturing a stacked hologram element in which the red hologram layer, the green hologram layer, and the blue hologram layer are aligned with high precision.

[0011] In order to solve the above problems, the inventors of the present invention conducted intensive studies.

[0012] Research has revealed that a red hologram is created by irradiating a photosensitive material, such as a photopolymer, with light having a red wavelength from two different directions. By irradiating the red hologram with a first illumination light having a red wavelength from approximately one of the two directions and then photographing the red hologram from the other of the two directions, the red hologram can be photographed with high contrast compared to the exterior of the red hologram (such as the portion of the photosensitive material where the red hologram has not been formed). The same is true for green and blue hologram layers.

[0013] Therefore, by performing image processing on each captured image obtained by capturing each hologram layer as described above, the coordinates of the outer edge of each hologram layer can be detected with high precision. If each hologram layer is a rectangle of identical dimensions, the coordinates of a corner or a portion of a side of each hologram layer can be detected with high precision. Furthermore, it has been discovered that by adjusting the positions of each hologram layer so that the coordinates of at least two corners of each hologram layer are aligned, or so that the coordinates of at least two mutually orthogonal portions of a side of each hologram layer are aligned, or so that the coordinates of at least one corner and at least one portion of a side of each hologram layer are aligned, and then laminating the adjusted hologram layers, a stacked hologram element can be manufactured in which the hologram layers are aligned with high precision.

[0014] The present invention has been completed based on the above-mentioned findings of the inventors of the present invention.

[0015] That is, to solve the above-mentioned technical problems, the present invention provides a method for manufacturing a stacked hologram element, the method comprising stacking a red hologram layer, a green hologram layer, and a blue hologram layer, wherein the red hologram layer is a hologram layer generated by irradiating a photosensitive material with light having a red wavelength from two different directions, the green hologram layer is a hologram layer generated by irradiating the photosensitive material with light having a green wavelength from the two directions, and the blue hologram layer is a hologram layer generated by irradiating the photosensitive material with light having a blue wavelength from the two directions, wherein the red hologram layer, the green hologram layer, and the blue hologram layer are rectangular and have the same size. The method comprises a captured image acquisition step of irradiating the red hologram layer with first illumination light having a red wavelength from approximately one of the two directions and capturing the red hologram from the other of the two directions to thereby capture a first captured image, irradiating the green hologram layer with second illumination light having a green wavelength from approximately the one direction to thereby capture a second captured image, and capturing the green hologram layer from approximately the one direction to thereby capture a second captured image. a step of irradiating the blue hologram with third illumination light having a wavelength including a blue wavelength and photographing the blue hologram from the other direction to obtain a third photographed image; a step of performing image processing on the first photographed image, the second photographed image, and the third photographed image to detect coordinates of corners or portions of sides of the red hologram, the green hologram, and the blue hologram; a step of adjusting the positions of the red, green, and blue holograms so that the coordinates of at least two corners of the red, green, and blue holograms coincide, or so that the coordinates of portions of at least two mutually orthogonal portions of the sides of the red, green, and blue holograms coincide, or so that the coordinates of at least one corner and at least one portion of the sides of the red, green, and blue holograms coincide; and a step of laminating the red, green, and blue holograms after the position adjustment.

[0016] In the present invention, the “red wavelength” refers to, for example, a wavelength of 600 nm to 700 nm, the “green wavelength” refers to, for example, a wavelength of 500 nm to 560 nm, and the “blue wavelength” refers to, for example, a wavelength of 430 nm to 500 nm.

[0017] In the present invention, "near one direction" is a concept that includes not only directions that are completely consistent with one direction (the directions of the first illumination light, the second illumination light, and the third illumination light irradiated to generate each hologram layer), but also directions that make an angle within ±15° with one direction.

[0018] According to the present invention, in the first captured image acquired in the captured image acquisition step, as discovered by the present inventors, the red hologram is captured with a higher contrast than the exterior of the red hologram (e.g., the portion of the photosensitive material where the red hologram is not formed). Similarly, in the second captured image acquired in the captured image acquisition step, the green hologram is captured with a higher contrast than the exterior of the green hologram. Furthermore, in the third captured image acquired in the captured image acquisition step, the blue hologram is captured with a higher contrast than the exterior of the blue hologram. Therefore, in the coordinate detection step, by performing image processing on the first, second, and third captured images, the coordinates of a corner or a portion of an edge of each hologram (the red hologram, the green hologram, and the blue hologram) can be detected with high precision.

[0019] Furthermore, according to the present invention, in the position adjustment step, the positions of the hologram layers are adjusted so that the coordinates of at least two corners of each hologram layer are aligned, or so that the coordinates of at least two mutually orthogonal sides of each hologram layer are aligned, or so that the coordinates of at least one corner and at least one side of each hologram layer are aligned, and in the laminating step, the position-adjusted hologram layers are laminated. This makes it possible to manufacture a laminated hologram element in which the hologram layers are aligned with high precision.

[0020] According to the present invention, the problem of marks remaining in each holographic layer, as in the past, does not occur. Furthermore, according to the present invention, position adjustment is performed based on the coordinates of the corners or a portion of the sides of each holographic layer itself. This improves alignment accuracy compared to conventional methods of position adjustment based on the coordinates of alignment marks provided on the outside of each holographic layer.

[0021] The laminated holographic element produced by the present invention is not limited to a structure in which holographic layers are directly laminated, but may also be a structure in which holographic substrates having a substrate and a holographic layer provided on the substrate are laminated.

[0022] In this case, in the present invention, the stacked hologram element is manufactured by stacking a red hologram substrate having a first substrate and the red hologram layer provided on the first substrate, a green hologram substrate having a second substrate and the green hologram layer provided on the second substrate, and a blue hologram substrate having a third substrate and the blue hologram layer provided on the third substrate. In the captured image acquisition step, the red hologram substrate is irradiated with the first illumination light to obtain the first captured image, the green hologram substrate is irradiated with the second illumination light to obtain the second captured image, and the blue hologram substrate is irradiated with the third illumination light to obtain the third captured image. In the position adjustment step, the positions of the red, green, and blue hologram substrates are adjusted. In the laminating step, the red, green, and blue hologram substrates after the position adjustment are laminated.

[0023] In the present invention, it is preferable that the red hologram layer, the green hologram layer, and the blue hologram layer are volume hologram layers (holograms having a three-dimensional refractive index distribution structure).

[0024] In the present invention, the stacked holographic element is preferably used as a light guide plate for an AR (Augmented Reality) device. An AR device refers to a device such as smart glasses that displays text information and virtual content alongside the real world. Light corresponding to the text information and virtual content (red, green, and blue wavelengths) is guided by the light guide plate to a location where light from the real world is received.

[0025] In the present invention, preferably, the first substrate, the second substrate, and the third substrate are made of glass or resin.

[0026] Effects of the Invention

[0027] According to the present invention, a stacked holographic element can be manufactured in which the red, green, and blue holographic layers are aligned with high precision. When the stacked holographic element is used as a light guide plate, the following advantages can be achieved: the guiding directions of the red, green, and blue wavelengths of light are less likely to deviate, thereby improving color reproducibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram schematically showing the general structure of the multilayer hologram element 100 manufactured by the manufacturing method according to the first embodiment of the present invention and the state of light guidance by the multilayer hologram element 100.

[0029] Figure 2 It shows Figure 1FIG. 1 is a flow chart showing the schematic steps of a method for manufacturing the laminated holographic optical element 100. FIG.

[0030] Figure 3 It is schematically shown Figure 1 FIG. 2 is a side view schematically showing the steps of a method for manufacturing the stacked holographic optical element 100. FIG.

[0031] Figure 4 It is a schematic illustration Figure 1 The diagram shows a method of producing the red hologram layer 20 of the red hologram substrate 1 and a state of light reflection by the red hologram layer 20.

[0032] Figure 5 It is a schematic illustration Figure 2 FIG. 1 shows a diagram of a captured image acquisition step ST12 and a coordinate detection step ST13 .

[0033] Figure 6 This is a diagram schematically showing the general structure of a multilayer hologram element 100A manufactured by the manufacturing method according to the second embodiment of the present invention and the state of light guidance by the multilayer hologram element 100A.

[0034] Figure 7 It shows Figure 6 FIG. 1 is a flow chart showing the schematic steps of a method for manufacturing the laminated holographic optical element 100A.

[0035] Figure 8 It is schematically shown Figure 6 FIG. 2 is a side view schematically showing the steps of a method for manufacturing the multilayer holographic optical element 100A.

[0036] Description of Reference Numerals

[0037] 100, 100A: stacked holographic element; 50a: first substrate; 50b: second substrate; 50c: third substrate; 1: red holographic substrate; 2: green holographic substrate; 3: blue holographic substrate; 4a, 4b: adsorption table; 5a, 5b: shooting unit; 6a, 6b: light source; 10: photosensitive material; 20, 20a, 20b: red holographic layer; 30, 30a, 30b: green holographic layer; 40, 40a, 40b: blue holographic layer; 60: substrate. DETAILED DESCRIPTION

[0038] The following describes a method for manufacturing a stacked holographic element according to embodiments (first and second embodiments) of the present invention, using the examples of a stacked holographic element used as a light guide plate for an AR device, with appropriate reference to the accompanying drawings. It should be noted that the figures are provided for reference only, and the dimensions, scales, and shapes of the components shown in the figures may differ from the actual dimensions.

[0039] [First embodiment]

[0040] <Structure of Laminated Hologram Element 100>

[0041] Figure 1 This is a diagram schematically showing the general structure of the multilayer hologram element 100 manufactured by the manufacturing method according to the first embodiment of the present invention and the state of light guidance by the multilayer hologram element 100. Figure 1 (a) shows a side view of a stacked holographic element, Figure 1 (b) shows a top view of the stacked holographic element, Figure 1 (c) shows the case of light guidance by stacked holographic elements. Figure 1 In the figure, the Z direction indicates the thickness direction of the stacked hologram element, the X direction indicates a direction perpendicular to the Z direction and parallel to one side of each hologram layer, and the Y direction indicates a direction perpendicular to the Z direction and the X direction.

[0042] like Figure 1 As shown in FIG. 1( a ), the stacked hologram element 100 of the first embodiment has a structure in which a red hologram substrate 1 having a first substrate 50 a and a red hologram layer 20 provided on the first substrate 50 a, a green hologram substrate 2 having a second substrate 50 b and a green hologram layer 30 provided on the second substrate 50 b, and a blue hologram substrate 3 having a third substrate 50 c and a blue hologram layer 40 provided on the third substrate 50 c are stacked. Furthermore, in addition to the red hologram substrate 1, the green hologram substrate 2, and the blue hologram substrate 3, the stacked hologram element 100 of the first embodiment has a structure in which a substrate 60 is stacked on the green hologram layer 30 of the green hologram substrate 2.

[0043] The red hologram 20 is a hologram (volume hologram) generated by irradiating the photosensitive material 10 with light of a red wavelength from two different directions. The green hologram 30 is a hologram (volume hologram) generated by irradiating the photosensitive material 10 with light of a green wavelength from the two directions. The blue hologram 40 is a hologram (volume hologram) generated by irradiating the photosensitive material 10 with light of a blue wavelength from the two directions.

[0044] like Figure 1 As shown in (b), the green hologram layer 30 is rectangular and is formed on a portion of the photosensitive material 10 which is also rectangular. The stacked hologram element 100 of the first embodiment is used as a light guide plate for AR equipment. Therefore, the green hologram layer 30 includes a rectangular green hologram layer 30a called an incoupling portion for inputting light to be guided and a rectangular green hologram layer 30b called an eye box for emitting guided light. Although Figure 1Although not shown in (b), the red hologram 20 is also rectangular and is formed on a portion of the rectangular photosensitive material 10. The red hologram 20 includes a rectangular red hologram 20a called an incoupling portion and a rectangular red hologram 20b called an eyebox. Figure 1 Although not shown in (b), the blue hologram 40 is also rectangular and is formed on a portion of the rectangular photosensitive material 10. The blue hologram 40 includes a rectangular blue hologram 40a called an incoupling portion and a rectangular blue hologram 40b called an eyebox.

[0045] Red hologram 20, green hologram 30, and blue hologram 40 have the same size. Specifically, red hologram 20a, green hologram 30a, and blue hologram 40a have the same size, and red hologram 20b, green hologram 30b, and blue hologram 40b have the same size.

[0046] like Figure 1 As shown in (c) of FIG. 5 , when the red light L1, the green light L2, and the blue light L3 are incident on the coupling-in portion (the red hologram 20 a, the green hologram 30 a, and the blue hologram 40 a) of the stacked hologram element 100 having the above structure, each light L1 to L3 is reflected by each hologram 20 a to 40 a, the third substrate 50 c, and the substrate 60, and then is emitted from the eye box (the red hologram 20 b, the green hologram 30 b, and the blue hologram 40 b).

[0047] For example, when people Figure 1 When the eye box is visually confirmed from below the stacked holographic element 100 shown in (c), the human eye reflects the image of the real world existing above the stacked holographic element 100 (receives light from the real world), and also reflects light L1 to L3 corresponding to the text information and virtual content guided to the eye box (receives light L1 to L3), thereby realizing AR.

[0048] <Method for Manufacturing Laminated Hologram Element 100>

[0049] Hereinafter, a method for manufacturing the multilayer holographic optical element 100 having the above-mentioned structure will be described.

[0050] Figure 2 This is a flow chart showing the schematic steps of the method for manufacturing the multilayer holographic optical element 100 according to the first embodiment. Figure 3 It is a side view schematically showing the general steps of the method for manufacturing the multilayer holographic optical element 100 according to the first embodiment.

[0051] like Figure 2As shown, the manufacturing method of the first embodiment mainly includes a hologram substrate preparing step ST11 , a captured image acquiring step ST12 , a coordinate detecting step ST13 , a position adjusting step ST14 , and a bonding step ST15 .

[0052] (Hologram Substrate Preparation Step ST11)

[0053] In the hologram substrate preparation step ST11 , a red hologram substrate 1 , a green hologram substrate 2 , and a blue hologram substrate 3 are prepared.

[0054] Figure 4 This is a diagram schematically illustrating a method for producing the red hologram layer 20 included in the red hologram substrate 1 and a state of light reflection by the red hologram layer 20 .

[0055] like Figure 4 As shown in (a), when generating the red hologram layer 20, a photosensitive material 10 must first be prepared. The photosensitive material 10 may be a single photosensitive resin such as a photopolymer or photoresist, or a laminate of a photosensitive resin and a base material. For example, the photosensitive resin may be the photopolymer "Bayfol (registered trademark) HX200" manufactured by Covestro. Furthermore, the base material may be glass or TAC (triacetyl cellulose).

[0056] Then, if Figure 4 As shown in (b), the red hologram layer 20 is generated by irradiating the photosensitive material 10 with red wavelength light IL from two different directions (a direction forming an angle α with the XY plane (hereinafter referred to as the "α direction") and a direction forming an angle β with the XY plane (hereinafter referred to as the "β direction") to generate a red hologram layer 20. Specifically, by irradiating the photosensitive material 10 with interference light of red wavelength light IL from two directions, the monomer component of the irradiated portion of the photosensitive material 10 is diffused to generate a refractive index distribution, thereby generating a red hologram layer 20. In the first embodiment, since the red hologram layer 20 is generated in the photosensitive material 10, the red hologram layer 20 is generated in the photosensitive material 10. The red hologram 20 forms a portion of the photosensitive material 10 (generating the coupling portion (red hologram 20a) and the eyebox (red hologram 20b)). Therefore, for example, only a portion of the photosensitive material 10 is irradiated with light IL having a red wavelength. To maintain coherence, it is preferred that the red wavelength light IL be split using a polarization beam splitter, emitted from a single laser light source, and the polarization axis of one of the split beams be rotated using a half-wave plate to align with the polarization axis of the other beam. This beam is then amplified and flattened using a magnifying lens and a collimating lens, and then irradiated from two directions.

[0057] like Figure 4As shown in (c), when the coupling portion (red hologram 20a) of the red hologram 20 manufactured as described above is irradiated with red wavelength light L1 from one direction (β direction) of the two directions (α direction and β direction) from which the red wavelength light IL is irradiated when the red hologram 20 is generated, the light L1 is reflected in the other direction (α direction) of the two directions (α direction and β direction). Then, the reflected light L1 is as described above. Figure 1 As shown in (c), the light is guided toward the eye box (red hologram layer 20b).

[0058] The green hologram layer 30 included in the green hologram substrate 2 is produced in the same manner as the red hologram layer 20, except that the light irradiated onto the photosensitive material 10 is light of a green wavelength. The blue hologram layer 40 included in the blue hologram substrate 3 is produced in the same manner as the red hologram layer 20, except that the light irradiated onto the photosensitive material 10 is light of a blue wavelength.

[0059] The red holographic substrate 1 is manufactured by laminating the red holographic layer 20 on the first substrate 50a via an appropriate adhesive or using the red holographic layer 20 having self-adhesive properties. The green holographic substrate 2 is manufactured by laminating the green holographic layer 30 on the second substrate 50b via an appropriate adhesive or using the green holographic layer 30 having self-adhesive properties. The blue holographic substrate 3 is manufactured by laminating the blue holographic layer 40 on the third substrate 50c via an appropriate adhesive or using the blue holographic layer 40 having self-adhesive properties.

[0060] As the first substrate 50a, the second substrate 50b, and the third substrate 50c, for example, glass, polycarbonate, polyamide, acrylic, or other resin is used. The same applies to the substrate 60 described later.

[0061] In the hologram substrate preparation step ST11 , the red hologram substrate 1 , the green hologram substrate 2 , and the blue hologram substrate 3 manufactured as described above are prepared.

[0062] like Figure 3 (a)~ Figure 3 As shown in (c), in the first embodiment, the red holographic substrate 1 and the blue holographic substrate 3 prepared in the holographic substrate preparation step ST11 are first bonded together, and at this time, the image acquisition step ST12, the coordinate detection step ST13, the position adjustment step ST14 and the bonding step ST15 are performed.

[0063] (Photographed Image Acquisition Step ST12)

[0064] Figure 5 1 and 2 are diagrams schematically illustrating the captured image acquisition step ST12 and the coordinate detection step ST13 .

[0065] In the captured image acquisition step ST12, initially, Figure 3 As shown in (a), the red hologram substrate 1 and the blue hologram substrate 3 are arranged opposite to each other in the Z direction (the thickness direction of each substrate). Figure 5 As shown in (a), the red hologram substrate 1 is sucked (vacuumed) by the suction stage 4a, and the blue hologram substrate 3 is sucked (vacuumed) by the suction stage 4b arranged opposite to the suction stage 4a in the Z direction.

[0066] Then, if Figure 5 As shown in (b), by moving the adsorption stages 4a and 4b the same distance in the horizontal direction (e.g., the Y direction) (and thereby also moving the red hologram substrate 1 and the blue hologram substrate 3 in the horizontal direction), the red hologram layer 20 of the red hologram substrate 1 is brought into opposition with the imaging unit 5a in the Z direction, and the blue hologram layer 40 of the blue hologram substrate 3 is brought into opposition with the imaging unit 5b in the Z direction. The light source 6a is configured so that the light emitted by it is irradiated within the field of view of the imaging unit 5a. The light source 6b is configured so that the light emitted by it is irradiated within the field of view of the imaging unit 5b.

[0067] As the imaging units 5a and 5b, for example, CCD (charge coupled device) area sensors or CMOS (complementary metal oxide semiconductor) area sensors (e.g., "CA-H500MX" manufactured by KEYENCE Corporation) can be used. As the light source 6a, for example, a red LED (light emitting diode) light source (e.g., "HLV3-22RD-2" manufactured by CCS Corporation) can be used. As the light source 6b, for example, a blue LED light source (e.g., "HLV3-22BL-2" manufactured by CCS Corporation) can be used.

[0068] Then, in Figure 5 In the state shown in (b), the red hologram layer 20 of the red hologram substrate 1 is irradiated with a first illumination light having a red wavelength from near one of the two directions (α direction, β direction) by the light source 6a, and the red hologram layer 20 is photographed from the other of the two directions (α direction, β direction) (β direction) by the photographing unit 5a, thereby obtaining a first photographed image. It should be noted that from the viewpoint of suppressing the distortion of the first photographed image, it is preferable that the β direction is set to β = 90°. In this case, it is necessary to set the β direction (refer to Figure 4 (b)) is also set to β = 90°.

[0069] Likewise, in Figure 5In the state shown in (b), the blue hologram layer 40 of the blue hologram substrate 3 is irradiated with third illumination light having a blue wavelength from near one direction (the α direction) of the two directions (the α direction, the β direction) by the light source 6b, and the blue hologram layer 40 is photographed from the other direction (the β direction) of the two directions (the α direction, the β direction) by the photographing unit 5b, thereby acquiring a third photographed image.

[0070] It should be noted that in order to accurately detect coordinates in the coordinate detection step ST13 described later, it is preferable to increase the resolution of the first and third captured images. Therefore, it is preferable that the field of view of the imaging unit 5a is limited to the vicinity of a portion of the red hologram 20 where coordinates are to be detected, rather than the entire red hologram layer 20, to acquire the first captured image. Furthermore, when detecting the coordinates of another portion of the red hologram 20, the adsorption stage 4a can be moved horizontally (in the X or Y direction) relative to the imaging unit 5a (and the red hologram substrate 1 can be moved horizontally) to obtain the first captured image by setting the field of view of the imaging unit 5a to the vicinity of the other portion. Alternatively, a plurality of imaging units 5a may be provided, corresponding to the number of portions where coordinates are to be detected. The same applies to the imaging unit 5b.

[0071] (Coordinate Detection Step ST13)

[0072] In the coordinate detection step ST13 , the first captured image and the third captured image are subjected to image processing, thereby detecting the coordinates (XY coordinates) of a corner or a part of a side of each of the red hologram layer 20 and the blue hologram layer 40 .

[0073] Figure 5 (c) shows an example of a corner portion of the blue hologram layer 40 whose coordinates are to be detected in the coordinate detection step ST13. Figure 5 In the example shown in (c), corner A of the blue hologram 40a (coupling portion) and corner B of the blue hologram 40b (eye box) are detected. Figure 5 (d) shows an example of a third captured image of the vicinity of the corner B of the blue hologram layer 40b acquired in the captured image acquisition step ST12 described above.

[0074] like Figure 5As shown in (d), in the third captured image, the blue hologram 40b is captured with a higher contrast than the exterior of the blue hologram 40b (the portion of the photosensitive material 10 where the hologram 40 is not formed). Therefore, by performing image processing (e.g., binarization or edge detection) on the third captured image, the coordinates of the corner B of the blue hologram 40b can be detected with high precision. The same applies to the corner A of the blue hologram 40a. Furthermore, although not shown in the figure, to detect the coordinates of the corners A and B of the blue hologram 40 in the third captured image, the coordinates of the corners A and B of the red hologram 20 are similarly detected in the first captured image.

[0075] It should be noted that the coordinates of the corners A and B or the coordinates of the portion of the side detected for the first and third captured images are directly relative coordinates within the fields of view of the respective imaging units 5a and 5b. Since the positions of the imaging units 5a and 5b relative to a predetermined, identical reference position are known in advance, the relative coordinates of the corners A and B or the portion of the side detected for the first and third captured images can be corrected according to the positions of the imaging units 5a and 5b, thereby calculating the absolute coordinates of the corners A and B or the portion of the side relative to the identical reference position. These absolute coordinates are used in the position adjustment step ST14 described below.

[0076] (Position Adjustment Step ST14)

[0077] In the position adjustment step ST14, at least two corners of the red hologram layer 20 and the blue hologram layer 40 (for example, Figure 5 The positions of the red hologram layer 20 and the blue hologram layer 40 are adjusted (the positions of the red hologram substrate 1 and the blue hologram substrate 3 are adjusted) so that the coordinates of the corners A and B shown in (c) are respectively consistent, or so that the coordinates of parts of the sides of at least two mutually orthogonal portions of the red hologram layer 20 and the blue hologram layer 40 are respectively consistent, or so that the coordinates of the corners of at least one portion of the red hologram layer 20 and the blue hologram layer 40 and the coordinates of parts of the sides of at least one portion are respectively consistent.

[0078] Specifically, the positions of the red holographic substrate 1 and the blue holographic substrate 3 are adjusted by moving at least one of the adsorption stage 4a for adsorbing the red holographic substrate 1 and the adsorption stage 4b for adsorbing the blue holographic substrate 3 in the X direction, in the Y direction, or in the Z direction. This adjusts the positions of the red holographic substrate 1 and the blue holographic substrate 3, thereby adjusting the positions of the red holographic layer 20 and the blue holographic layer 40.

[0079] (Laminating step ST15)

[0080] In the laminating step ST15, the red hologram layer 20 and the blue hologram layer 40 whose positions have been adjusted are laminated together (the red hologram substrate 1 and the blue hologram substrate 3 whose positions have been adjusted are laminated together).

[0081] Specifically, if Figure 3 As shown in (b), by moving the adsorption stages 4a and 4b by the same distance in the horizontal direction (e.g., the Y direction) (since they are moved by the same distance, the positions of the red hologram layer 20 and the blue hologram layer 40 remain unchanged), the imaging units 5a and 5b and the light sources 6a and 6b are no longer present between the adsorption stages 4a and 4b. Figure 3 As shown in (b), for example, an ultraviolet curing adhesive 70 is applied to the blue hologram substrate 3 to bond the red hologram substrate 1 and the blue hologram substrate 3 together. Figure 3 As shown in (c), the red hologram substrate 1 and the blue hologram substrate 3 are brought into contact. Specifically, at least one of the adsorption stages 4a and 4b is moved in the Z direction to bring the red hologram substrate 1 and the blue hologram substrate 3 into contact. Finally, ultraviolet rays are irradiated from an ultraviolet irradiation unit (not shown) onto the adhesive 70 to cure the adhesive 70, thereby bonding the red hologram substrate 1 and the blue hologram substrate 3.

[0082] It should be noted that in order to bond the red hologram substrate 1 and the blue hologram substrate 3 together while they are aligned with high precision, the bonding step ST15 is preferably performed in a vacuum chamber (not shown). Specifically, it is preferred that the application of the adhesive 70, the movement of at least one of the adsorption stages 4a and 4b in the Z direction, and the irradiation with ultraviolet light are performed after the adsorption stages 4a and 4b are brought into the vacuum chamber.

[0083] Through the above-described steps, the red hologram substrate 1 and the blue hologram substrate 3 are bonded together to obtain Figure 3 The laminate M1 of the red hologram substrate 1 and the blue hologram substrate 3 is shown in (c), but the green hologram substrate 2 has not yet been attached ( Figure 2 (The answer is "No" in step ST16 shown in the figure). Therefore, the manufacturing method of the first embodiment executes the captured image acquisition step ST12 to the bonding step ST15 again. The following description of the second captured image acquisition step ST12 to the bonding step ST15 will appropriately omit the parts common to the first captured image acquisition step ST12 to the bonding step ST15 described above.

[0084] (Second Captured Image Acquisition Step ST12)

[0085] like Figure 3 As shown in (d), in the second captured image acquisition step ST12, the same adsorption stages 4a and 4b as above are used ( Figure 3(not shown in the figure), the green hologram substrate 2 and the laminate M1 are arranged to face each other in the Z direction. Subsequently, although not shown in the figure, after the adsorption stages 4a and 4b are moved the same distance in the horizontal direction (e.g., the Y direction), a light source (not shown) illuminates the green hologram layer 30 of the green hologram substrate 2 with a second illumination light having a wavelength including green from near one of the two directions (α direction and β direction) described above. An imaging unit (not shown) then captures the green hologram layer 30 of the green hologram substrate 2 from the other of the two directions (α direction and β direction) (β direction), thereby acquiring a second captured image. As the light source for illuminating the second illumination light, a green LED light source (e.g., "HLV3-22GR-2" manufactured by CCS Corporation) can be used, and as the imaging unit for capturing the green hologram layer 30, a CCD area sensor or a CMOS area sensor (e.g., "CA-H500MX" manufactured by Keyence Corporation) can be used.

[0086] (Second Coordinate Detection Step ST13)

[0087] In the second coordinate detection step ST13 , the coordinates (XY coordinates) of a corner or a part of the side of the green hologram layer 30 are detected by performing image processing on the second captured image.

[0088] It should be noted that, since the coordinates (XY coordinates) of the corner or part of the edge of the red holographic layer 20 of the red holographic substrate 1 constituting the stack M1 were detected in the previous coordinate detection process ST13, the coordinates after the position adjustment in the previous position adjustment process ST14 can also be grasped. Therefore, there is no need to re-detect in this second coordinate detection process ST13.

[0089] (Second Position Adjustment Step ST14)

[0090] In the second position adjustment step ST14, the positions of the green hologram layer 30 and the red hologram layer 20 of the laminate M1 are adjusted (the positions of the green hologram substrate 2 and the laminate M1 are adjusted) so that the coordinates of at least two corners of the green hologram layer 30 and the red hologram layer 20 of the laminate M1 are aligned, or the coordinates of at least two mutually orthogonal sides of the green hologram layer 30 and the red hologram layer 20 of the laminate M1 are aligned, or the coordinates of at least one corner and at least one side of the green hologram layer 30 and the red hologram layer 20 of the laminate M1 are aligned.

[0091] Specifically, the positions of the green holographic substrate 2 and the stacked body M1 are adjusted by moving at least one of the adsorption stage 4a for adsorbing the green holographic substrate 2 and the adsorption stage 4b for adsorbing the stacked body M1 in the X direction, in the Y direction, or in the Z direction. This adjusts the positions of the green holographic substrate 2 and the stacked body M1, thereby adjusting the positions of the green holographic layer 30 and the red holographic layer 20.

[0092] (Second Lamination Step ST15)

[0093] In the second laminating step ST15, the position-adjusted green hologram layer 30 and the red hologram layer 20 are laminated together (the position-adjusted green hologram substrate 2 and the red hologram substrate 1 of the laminate M1 are laminated together).

[0094] Specifically, if Figure 3 As shown in (e), after the adsorption stages 4a and 4b are moved the same distance in the horizontal direction (for example, the Y direction) to a state where there is no imaging unit and light source between the adsorption stages, for example, an ultraviolet curing adhesive 70 is applied to the laminate M1. Figure 3 As shown in (f), at least one of the adsorption stages 4a and 4b is moved in the Z direction to bring the green hologram substrate 2 into contact with the red hologram substrate 1 of the laminate M1. Finally, ultraviolet rays are irradiated from an ultraviolet irradiation unit (not shown) onto the adhesive 70 to cure the adhesive 70, thereby bonding the green hologram substrate 2 and the laminate M1 to obtain the laminate M2.

[0095] By executing the captured image acquisition step ST12 twice in total, the first captured image, the second captured image, and the third captured image are acquired in the entire captured image acquisition step ST12 .

[0096] Furthermore, by executing the coordinate detection step ST13 twice in total, the coordinates of a corner or a part of a side of each of the red hologram layer 20 , the green hologram layer 30 , and the blue hologram layer 40 are detected in the entire coordinate detection step ST13 .

[0097] Furthermore, by executing the position adjustment step ST14 twice in total, the entire position adjustment step ST14 adjusts the positions of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 (adjusts the positions of the red hologram substrate 1, the green hologram substrate 2, and the blue hologram substrate 3) so that the coordinates of at least two corners of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 become identical, or so that the coordinates of at least two mutually orthogonal sides of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 become identical, or so that the coordinates of at least one corner and a part of at least one side of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 become identical.

[0098] Furthermore, by performing the laminating step ST15 twice in total, the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 after position adjustment are laminated in the entire laminating step ST15 (the red hologram substrate 1, the green hologram substrate 2, and the blue hologram substrate 3 after position adjustment are laminated).

[0099] Through the above steps, the lamination of all hologram substrates (red hologram substrate 1, green hologram substrate 2 and blue hologram substrate 3) is completed. Figure 2 In step ST16 shown in FIG, “Yes” is given), and thus the bonding of the substrate 60 is performed ( Figure 2 Step ST17 shown).

[0100] Specifically, if Figure 3 As shown in (g), the substrate 60 and the stacked body M2 are arranged opposite to each other in the Z direction using the same adsorption stages 4a and 4b as above. Figure 3 As shown in (h), for example, an ultraviolet curing adhesive 70 is applied to the laminate M1. Figure 3 As shown in (i), at least one of the adsorption stages 4a and 4b is moved in the Z direction to bring the substrate 60 and the laminate M2 into contact. Finally, ultraviolet rays are irradiated from an ultraviolet irradiation unit (not shown) onto the adhesive 70 to cure the adhesive 70, thereby bonding the substrate 60 and the laminate M2 to obtain the laminated hologram element 100.

[0101] Note that, since no hologram element is formed on the substrate 60 , it is not necessary to perform the captured image acquisition step ST12 to the position adjustment step ST15 before bonding the substrate 60 to the laminate M2 .

[0102] According to the method for manufacturing the stacked hologram element 100 according to the first embodiment described above, in the first captured image acquired in the captured image acquisition step ST12, the red hologram layer 20 is captured with high contrast relative to the exterior of the red hologram layer 20 (such as the portion of the photosensitive material 10 where the red hologram layer 20 is not formed). Similarly, in the second captured image acquired in the captured image acquisition step ST12, the green hologram layer 30 is captured with high contrast relative to the exterior of the green hologram layer 30. Furthermore, in the third captured image acquired in the captured image acquisition step ST12, the blue hologram layer 40 is captured with high contrast relative to the exterior of the blue hologram layer 40. Therefore, in the coordinate detection step ST13, by performing image processing on the first, second, and third captured images, the coordinates of the corners or portions of the sides of each hologram layer (the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40) can be detected with high precision.

[0103] Furthermore, according to the method for manufacturing the stacked hologram element 100 of the first embodiment, in the position adjustment step ST14, the positions of the hologram layers 20, 30, 40 are adjusted so that the coordinates of at least two corners of each hologram layer 20, 30, 40 are aligned, or the coordinates of at least two mutually orthogonal sides of each hologram layer 20, 30, 40 are aligned, or the coordinates of at least one corner and at least one side of each hologram layer 20, 30, 40 are aligned. In the laminating step ST15, the positionally adjusted hologram layers 20, 30, 40 are laminated. Therefore, the stacked hologram element 100 in which the hologram layers 20, 30, 40 are aligned with each other with high precision can be manufactured.

[0104] [Second embodiment]

[0105] <Structure of Laminated Hologram Element 100A>

[0106] The stacked hologram element 100 of the first embodiment is structured by stacking hologram substrates (red hologram substrate 1, green hologram substrate 2, blue hologram substrate 3) each including substrates (first substrate 50a, second substrate 50b, third substrate 50c) and hologram layers (red hologram layer 20, green hologram layer 30, blue hologram layer 40) provided on the substrates. However, the stacked hologram element 100A of the second embodiment differs in that it employs a structure in which the hologram layers are directly stacked. Hereinafter, regarding the structure of the stacked hologram element 100A of the second embodiment, the same reference numerals are used for the same components as those of the stacked hologram element 100 of the first embodiment, and description thereof will be omitted as appropriate, with the main focus being on the differences.

[0107] Figure 6 This is a diagram schematically showing the general structure of a multilayer hologram element 100A manufactured by the manufacturing method according to the second embodiment of the present invention and the state of light guidance by the multilayer hologram element 100A. Figure 6 (a) shows a side view of the stacked hologram element 100A, Figure 6 (b) shows the state of light guidance by the multilayer hologram element 100A.

[0108] like Figure 6As shown in FIG. 1( a ), the stacked hologram element 100A of the second embodiment has a structure in which the red hologram layers 20 (red hologram layer 20a, red hologram layer 20b), the green hologram layer 30 (green hologram layer 30a, green hologram layer 30b), and the blue hologram layer 40 (blue hologram layer 40a, blue hologram layer 40b) are directly stacked. Furthermore, the stacked hologram element 100A of the second embodiment has a structure in which, in addition to the red hologram layers 20, green hologram layer 30, and blue hologram layer 40, substrates 60 are stacked on the green hologram layer 30 and the blue hologram layer 40, respectively (the stacked body of the red hologram layers 20, green hologram layer 30, and blue hologram layer 40 is sandwiched between a pair of substrates 60).

[0109] like Figure 6 As shown in (b) of FIG. 2 , when the red wavelength light L1, the green wavelength light L2, and the blue wavelength light L3 are incident on the coupling portion (the red hologram layer 20a, the green hologram layer 30a, and the blue hologram layer 40a) of the stacked hologram element 100A having the above structure, each light L1 to L3 is reflected by each hologram layer 20a to 40a and the pair of substrates 60, and then is emitted from the eye box (the red hologram layer 20b, the green hologram layer 30b, and the blue hologram layer 40b).

[0110] For example, when people Figure 6 When the eye box is visually confirmed from below the stacked holographic element 100A shown in (b), the human eye reflects the image of the real world existing above the stacked holographic element 100A (receives light from the real world), and also reflects light L1 to L3 corresponding to the text information and virtual content guided to the eye box (receives light L1 to L3), thereby realizing AR.

[0111] <Method for Manufacturing Laminated Hologram Element 100A>

[0112] Hereinafter, a method for manufacturing the multilayer hologram element 100A having the above-mentioned structure will be described.

[0113] Figure 7 This is a flow chart showing the schematic steps of a method for manufacturing the multilayer holographic optical element 100A according to the second embodiment. Figure 8 It is a side view schematically showing the general steps of the method for manufacturing the multi-layer holographic optical element 100A according to the second embodiment.

[0114] like Figure 7 As shown, the manufacturing method of the second embodiment mainly includes a hologram layer preparation step ST21 , a captured image acquisition step ST22 , a coordinate detection step ST23 , a position adjustment step ST24 , and a bonding step ST25 .

[0115] (Hologram Layer Preparation Step ST21)

[0116] In the hologram layer preparation step ST21 , the red hologram layer 20 , the green hologram layer 30 , and the blue hologram layer 40 are prepared.

[0117] The hologram layer preparation step ST21 differs from the hologram substrate preparation step ST11 of the first embodiment in that the red hologram layer 20 is not laminated on the first substrate 50a, the green hologram layer 30 is not laminated on the second substrate 50b, and the blue hologram layer 40 is not laminated on the third substrate 50c. The method for forming the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 is the same as that of the hologram substrate preparation step ST11 of the first embodiment.

[0118] like Figure 8 (a)~ Figure 8 As shown in (d), in the second embodiment, the red hologram layer 20 and the blue hologram layer 40 prepared in the hologram layer preparation step ST21 are first bonded together, and at this time, the image acquisition step ST22, the coordinate detection step ST23, the position adjustment step ST24 and the bonding step ST25 are performed.

[0119] (Photographed Image Acquisition Step ST22)

[0120] In the captured image acquisition step ST22, initially, Figure 8 As shown in (a), the same adsorption stages 4a and 4b as those in the first embodiment are used. Figure 8 (not shown) to arrange the substrate 60 and the blue hologram layer 40 opposite to each other in the Z direction. Then, a suitable adhesive such as Figure 8 As shown in (b), by moving at least one of the adsorption stages 4a and 4b in the Z direction, the blue hologram layer 40 is laminated on the substrate 60 via the adhesive. Thus, a laminate N1 of the blue hologram layer 40 and the substrate 60 is obtained.

[0121] Then, if Figure 8 As shown in (c), the red hologram layer 20 and the laminate N1 are arranged to face each other in the Z direction using the adsorption stages 4a and 4b. Then, after the adsorption stages 4a and 4b are moved the same distance in the horizontal direction (e.g., the Y direction), a light source (not shown) illuminates the red hologram layer 20 with first illumination light having a red wavelength from approximately one of the two directions (α direction and β direction) as in the first embodiment. An imaging unit (not shown) then captures the red hologram layer 20 from the other of the two directions (α direction and β direction) (β direction), thereby acquiring a first captured image.

[0122] Similarly, a light source (not shown) is used to irradiate the blue hologram layer 40 constituting the stack N1 with third illumination light having a wavelength including a blue wavelength from near one direction (the α direction) of the two directions (the α direction, the β direction), and a photographing unit (not shown) is used to photograph the blue hologram layer 40 from the other direction (the β direction) of the two directions (the α direction, the β direction), thereby obtaining a third photographed image.

[0123] (Coordinate Detection Step ST23)

[0124] In the coordinate detection step ST23 , similarly to the coordinate detection step ST13 of the first embodiment, the coordinates (XY coordinates) of the corners or side portions of the red hologram 20 and the blue hologram 40 are detected by performing image processing on the first captured image and the third captured image.

[0125] (Position Adjustment Step ST24)

[0126] In the position adjustment step ST24, similarly to the position adjustment step ST14 of the first embodiment, the positions of the red hologram layer 20 and the blue hologram layer 40 are adjusted so that the coordinates of at least two corners of the red hologram layer 20 and the blue hologram layer 40 are aligned, or so that the coordinates of at least two mutually orthogonal sides of the red hologram layer 20 and the blue hologram layer 40 are aligned, or so that the coordinates of at least one corner and at least one side of the red hologram layer 20 and the blue hologram layer 40 are aligned.

[0127] Specifically, the positions of the red hologram layer 20 and the stack N1 are adjusted by moving at least one of the adsorption stage 4a for adsorbing the red hologram layer 20 and the adsorption stage 4b for adsorbing the stack N1 in the X direction, in the Y direction, or in the Z direction. This adjusts the positions of the red hologram layer 20 and the stack N1, thereby adjusting the positions of the red hologram layer 20 and the blue hologram layer 40.

[0128] (Laminating step ST25)

[0129] In the laminating step ST25, similarly to the laminating step ST15 of the first embodiment, the position-adjusted red hologram layer 20 and the blue hologram layer 40 are laminated (the position-adjusted red hologram layer 20 and the laminate N1 are laminated).

[0130] Specifically, by moving the adsorption stages 4a and 4b by the same distance in the horizontal direction (e.g., the Y direction) (since they are moved by the same distance, the positions of the red hologram layer 20 and the blue hologram layer 40 remain unchanged), a state is achieved where no imaging unit or light source exists between the adsorption stages 4a and 4b. Next, a suitable adhesive is applied to at least one of the red hologram layer 20 and the blue hologram layer 40, such as Figure 8 As shown in (d), at least one of the adsorption stages 4a and 4b is moved in the Z direction to laminate the red hologram layer 20 onto the blue hologram layer 40 of the laminate N1 via the adhesive, thereby bonding the red hologram layer 20 and the blue hologram layer 40 together.

[0131] Through the above-described steps, the red hologram layer 20 and the blue hologram layer 40 are bonded together to obtain Figure 8 The red hologram layer 20, the blue hologram layer 40 and the laminate N2 of the substrate 60 are shown in (d), but the green hologram layer 30 has not yet been attached ( Figure 7 Since the answer is "No" in step ST26 shown in the figure, the manufacturing method of the second embodiment executes the captured image acquisition step ST22 to the bonding step ST25 again.

[0132] (Second Captured Image Acquisition Step ST22)

[0133] like Figure 8 As shown in (e) of FIG. 2 , in the second captured image acquisition step ST22, the green hologram layer 30 and the laminate N2 are positioned opposite each other in the Z direction using the adsorption stages 4a and 4b. Then, after the adsorption stages 4a and 4b are moved the same distance in the horizontal direction (e.g., the Y direction), a light source (not shown) illuminates the green hologram layer 30 with a second illumination light having a green wavelength from approximately one of the two directions (α direction and β direction) described above. The green hologram layer 30 is then imaged from the other of the two directions (α direction and β direction) (β direction) by an imaging unit (not shown), thereby acquiring a second captured image.

[0134] (Second Coordinate Detection Step ST23)

[0135] In the second coordinate detection step ST23 , the coordinates (XY coordinates) of a corner or a part of a side of the green hologram layer 30 are detected by performing image processing on the second captured image.

[0136] It should be noted that, since the coordinates (XY coordinates) of the corner or part of the edge of the red holographic layer 20 constituting the stack N2 were detected in the previous coordinate detection process ST23, the coordinates after the position adjustment in the previous position adjustment process ST24 can also be grasped. Therefore, there is no need to re-detect in this second coordinate detection process ST23.

[0137] (Second Position Adjustment Step ST24)

[0138] In the second position adjustment step ST24, the positions of the green hologram layer 30 and the red hologram layer 20 of the stack N2 are adjusted (the positions of the green hologram layer 30 and the stack N2 are adjusted) so that the coordinates of at least two corners of the green hologram layer 30 and the red hologram layer 20 of the stack N2 coincide with each other, or the coordinates of at least two portions of mutually orthogonal sides of the green hologram layer 30 and the red hologram layer 20 of the stack N2 coincide with each other, or the coordinates of at least one corner and at least one portion of the side of the green hologram layer 30 and the red hologram layer 20 of the stack N2 coincide with each other.

[0139] Specifically, the positions of the green hologram layer 30 and the stack N2 are adjusted by moving at least one of the adsorption stage 4a for adsorbing the green hologram layer 30 and the adsorption stage 4b for adsorbing the stack N2 in the X direction, in the Y direction, or in the Z direction. This, in turn, adjusts the positions of the green hologram layer 30 and the stack N2.

[0140] (Second Lamination Step ST25)

[0141] In the second laminating step ST25, the position-adjusted green hologram layer 30 and the red hologram layer 20 are laminated together (the position-adjusted green hologram layer 30 and the laminate N2 are laminated together).

[0142] Specifically, the adsorption stages 4a and 4b are moved the same distance in the horizontal direction (e.g., the Y direction) to a state where there is no imaging unit or light source between the adsorption stages. Next, a suitable adhesive is applied to at least one of the green hologram layer 30 and the red hologram layer 20, such as Figure 8 As shown in (f), by moving at least one of the adsorption stages 4a and 4b in the Z direction, the green hologram layer 30 is laminated on the red hologram layer 20 of the laminate N2 via the adhesive, thereby bonding the green hologram layer 30 and the red hologram layer 20. In this way, a laminate N3 is obtained.

[0143] By executing the captured image acquisition step ST22 twice in total, the first captured image, the second captured image, and the third captured image are acquired in the entire captured image acquisition step ST22 .

[0144] Furthermore, by executing the coordinate detection step ST23 twice in total, the coordinates of a corner or a part of a side of each of the red hologram layer 20 , the green hologram layer 30 , and the blue hologram layer 40 are detected in the entire coordinate detection step ST23 .

[0145] Furthermore, by executing the position adjustment step ST24 twice in total, the positions of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 are adjusted in such a manner that the coordinates of the corners of at least two locations of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 are matched, or the coordinates of a portion of the sides of at least two locations orthogonal to each other of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 are matched, or the coordinates of the corner of at least one location and the coordinates of a portion of the side of at least one location of the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 are matched.

[0146] Furthermore, by performing the laminating step ST25 twice in total, the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 after the position adjustment are laminated together in the laminating step ST25.

[0147] Through the above steps, the lamination of all hologram layers (red hologram layer 20, green hologram layer 30 and blue hologram layer 40) is completed. Figure 7 In step ST26 shown in FIG, “Yes” is given), and thus the bonding of the substrate 60 is performed ( Figure 7 Step ST27 shown).

[0148] Specifically, if Figure 8 As shown in (g), the substrate 60 and the stacked body N3 are arranged opposite to each other in the Z direction using the same adsorption stages 4a and 4b as above. Figure 8 As shown in (h), for example, an ultraviolet curing adhesive 70 is applied to the laminate N3. Figure 8 As shown in (i), at least one of the adsorption stages 4a and 4b is moved in the Z direction to bring the substrate 60 and the laminate N3 into contact. Finally, ultraviolet rays are irradiated from an ultraviolet irradiation unit (not shown) onto the adhesive 70 to cure the adhesive 70, thereby bonding the substrate 60 and the laminate N3 to obtain the laminated hologram element 100A.

[0149] Note that, since no hologram element is formed on the substrate 60 , it is not necessary to perform the captured image acquisition step ST22 to the position adjustment step ST25 before bonding the substrate 60 to the laminate N3 .

[0150] According to the method for manufacturing the stacked hologram element 100A of the second embodiment described above, similarly to the method for manufacturing the stacked hologram element 100 of the first embodiment, the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40 are captured with high contrast in the first to third captured images. Therefore, by performing image processing on the first, second, and third captured images, the coordinates of a corner or a portion of an edge of each hologram layer (the red hologram layer 20, the green hologram layer 30, and the blue hologram layer 40) can be detected with high precision.

[0151] Furthermore, according to the method for manufacturing the stacked hologram element 100A of the second embodiment, similarly to the method for manufacturing the stacked hologram element 100 of the first embodiment, the positions of the hologram layers 20, 30, 40 are adjusted so that the coordinates of at least two corners of each hologram layer 20, 30, 40 are aligned, or the coordinates of at least two mutually orthogonal sides of each hologram layer 20, 30, 40 are aligned, or the coordinates of at least one corner and at least one side of each hologram layer 20, 30, 40 are aligned, and the position-adjusted hologram layers 20, 30, 40 are bonded together. This allows manufacturing the stacked hologram element 100A in which the hologram layers 20, 30, 40 are aligned with high precision.

Claims

1. A method for manufacturing a laminated holographic element, the method comprising laminating a red holographic layer, a green holographic layer, and a blue holographic layer, wherein the red holographic layer is a holographic layer generated by irradiating a photosensitive material with light of a red wavelength from two different directions, the green holographic layer is a holographic layer generated by irradiating the photosensitive material with light of a green wavelength from the two directions, and the blue holographic layer is a holographic layer generated by irradiating the photosensitive material with light of a blue wavelength from the two directions, wherein: The red holographic layer, the green holographic layer, and the blue holographic layer are rectangular with the same size. The method for manufacturing the stacked holographic optical element comprises: a captured image acquisition step of irradiating the red hologram layer with first illumination light having a red wavelength from approximately one of the two directions and photographing the red hologram layer from the other of the two directions, thereby acquiring a first captured image; irradiating the green hologram layer with second illumination light having a green wavelength from approximately the one direction and photographing the green hologram layer from the other direction, thereby acquiring a second captured image; and irradiating the blue hologram layer with third illumination light having a blue wavelength from approximately the one direction and photographing the blue hologram layer from the other direction, thereby acquiring a third captured image; a coordinate detection step of performing image processing on each of the first captured image, the second captured image, and the third captured image to detect coordinates of a corner or a portion of an edge of each of the red hologram layer, the green hologram layer, and the blue hologram layer; a position adjustment step of adjusting the positions of the red, green, and blue hologram layers so that the coordinates of at least two corners of each of the red, green, and blue hologram layers are aligned, or so that the coordinates of at least two mutually orthogonal portions of the sides of each of the red, green, and blue hologram layers are aligned, or so that the coordinates of at least one corner and at least one portion of the sides of each of the red, green, and blue hologram layers are aligned; as well as The laminating step laminates the red hologram layer, the green hologram layer, and the blue hologram layer after the positions have been adjusted.

2. The method for manufacturing a stacked holographic optical element according to claim 1, wherein: The stacked hologram element is manufactured by stacking a red hologram substrate having a first substrate and the red hologram layer provided on the first substrate, a green hologram substrate having a second substrate and the green hologram layer provided on the second substrate, and a blue hologram substrate having a third substrate and the blue hologram layer provided on the third substrate. In the captured image acquisition step, the red holographic substrate is irradiated with the first illumination light to obtain the first captured image, the green holographic substrate is irradiated with the second illumination light to obtain the second captured image, and the blue holographic substrate is irradiated with the third illumination light to obtain the third captured image. In the position adjustment step, the positions of the red hologram substrate, the green hologram substrate, and the blue hologram substrate are adjusted. In the bonding step, the red hologram substrate, the green hologram substrate, and the blue hologram substrate whose positions have been adjusted are bonded together.

3. The method for producing a stacked holographic optical element according to claim 1 or 2, wherein: The red holographic layer, the green holographic layer, and the blue holographic layer are volume holographic layers.

4. The method for producing a stacked holographic optical element according to claim 1 or 2, wherein: The stacked holographic element is used as a light guide plate for an augmented reality device.

5. The method for producing a stacked holographic optical element according to claim 1 or 2, wherein: The first substrate, the second substrate, and the third substrate are made of glass or resin.

Images