JP2012042736A - Method of manufacturing wavelength selective hologram and device for manufacturing wavelength selective hologram - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a wavelength selective hologram, which performs clear multiple recording of a hologram.SOLUTION: A method of manufacturing a wavelength selective hologram includes a layer formation process which forms a photosensitive material layer 120 sensitive to first light 151, 152 and second light 161, 162, and a recording process in which the first light 151, 152 and the second light 161, 162 are simultaneously made incident on the photosensitive material layer 120 with the same incident angle, both exposure time by the first light 151, 152 and the second light 161, 162 made coincident, and a hologram 130 including a first hologram and a second hologram is recorded in the photosensitive material layer 120.

Description

  The present invention relates to a method for manufacturing a wavelength selective hologram and an apparatus for manufacturing the same, and more particularly to a method for manufacturing a wavelength selective hologram that is a volume hologram and an apparatus for manufacturing the same.

  In recent years, diffractive optical elements and display devices using holographic technology have been developed. As a production method thereof, a method of recording a hologram by directly irradiating a hologram recording medium with laser light, and a reproduction generated from the master hologram by irradiating the master hologram on which a predetermined hologram pattern is formed. There is a method of recording a hologram using light. The former is a production method mainly applied when forming a hologram pattern of a master hologram or when the number of holograms to be produced is small. The latter is a manufacturing method applied to mass production of holograms because the hologram pattern formed on the master hologram can be transferred.

  When holographic technology is used for diffractive optical elements and display devices used in BD (Blu-ray Disc) or DVD (Digital Versatile Disc), hologram recording is performed to diffract light in different wavelength bands in the same desired direction. It is necessary to multiplex-record a plurality of holograms using light having different wavelengths at the same location in the medium. The holographically recorded hologram has a wavelength selectivity that diffracts only the reproduction light generated from the master hologram under a specific reproduction condition, and functions as a wavelength selective hologram.

  As a prior document disclosing a transfer method and apparatus using holography technology, there is Patent Document 1. In the transfer method described in Patent Document 1, after recording a plurality of hologram patterns under different recording conditions during master hologram recording, each hologram pattern formed on the master hologram is transferred under different reproduction conditions during transfer. Play one by one. In this way, the hologram is transferred into the recording material using clear reproduction light having no crosstalk.

  In the above method, when recording a wavelength-selective hologram, it reproduces individual holograms that are multiplexed and recorded under reproduction conditions with different wavelengths, thereby supporting interference fringes in a hologram recording medium for transfer. Exposure is performed.

  A photopolymer material is used as the hologram recording medium. When the photopolymer material is exposed to the interference light, the monomer is assembled and polymerized in the portion receiving the strong light, and the refractive index is changed. As a result, a refractive index difference is generated in the photopolymer due to the brightness and darkness of the interference fringes, and the hologram is recorded.

JP-A-7-281484

  When transferring multiplex-recorded holograms, if reproduction lights having different wavelengths are sequentially incident on the hologram recording medium, the holograms to be recorded later become unclear due to the influence of the previously recorded holograms. Specifically, refractive index modulation occurs in the photopolymer that is the hologram recording medium due to the hologram recorded earlier. Therefore, the next time the hologram is recorded, the reproduction light is scattered by the refractive index modulation generated in the photopolymer. As a result, the hologram recorded later becomes an unclear hologram.

  The present invention has been made in view of the above problems, and an object thereof is to provide a wavelength-selective hologram manufacturing method and a wavelength-selective hologram manufacturing apparatus capable of clearly multiplex-recording holograms. To do.

  In the method for producing a wavelength selective hologram according to the present invention, the first light having the first wavelength and the second light having the second wavelength different from the first wavelength are caused to interfere with each other in the photosensitive material layer. A first hologram that diffracts the first light and transmits the second light without diffracting, and a second hologram that diffracts the second light and transmits the first light without diffracting the wavelength. This is a method for producing a selective hologram. A method for producing a wavelength selective hologram includes a layer forming step of forming a photosensitive material layer that is sensitive to first light and second light, and a photosensitive material that simultaneously applies the first light and the second light at the same incident angle. And a recording step of recording the hologram including the first hologram and the second hologram on the photosensitive material layer with the exposure time by the first light and the exposure time by the second light being the same.

  In one embodiment of the present invention, the first light and the second light are irradiated with light having the first wavelength and light having the second wavelength, so that the light having the first wavelength and the second light have the second wavelength. It is generated by irradiating light having a first wavelength and light having a second wavelength onto a master hologram that generates a plurality of diffracted lights for each light having a wavelength. Further, in the recording step, the photosensitive material layer is exposed by causing the first light composed of a plurality of diffracted lights to interfere with each other and the second light composed of a plurality of diffracted lights to interfere with each other.

  Preferably, each master beam having a diffraction efficiency of each of the first light and the second light generated by the master hologram as the master hologram is irradiated onto the master hologram having the respective wavelengths of the first light and the second light. A recorded hologram is used to correspond to the output.

  The wavelength selective hologram manufacturing apparatus according to the present invention causes the first light having the first wavelength and the second light having the second wavelength different from the first wavelength to interfere with each other in the photosensitive material layer. In this case, the wavelength-selective hologram manufacturing apparatus includes a first hologram that diffracts the first light and transmits the second light, and a second hologram that diffracts the second light and transmits the first light. . The wavelength selective hologram manufacturing apparatus includes a first light source that emits light having a first wavelength and a second light source that emits light having a second wavelength. In addition, the wavelength selective hologram manufacturing apparatus includes an optical axis adjustment unit that aligns the optical axes of the light emitted from the first light source and the light emitted from the second light source, and the first light and the second light as photosensitive materials. An incident direction adjusting unit that makes the layer incident from the same direction; and an exposure adjusting unit that simultaneously adjusts the exposure time of the photosensitive material layer by the first light and the second light.

  In one embodiment of the present invention, the wavelength-selective hologram manufacturing apparatus emits light from the first light source and the second light source, so that each of the light having the first wavelength and the light having the second wavelength is obtained. Includes a master hologram for generating a plurality of diffracted lights. The first light and the second light are generated by irradiating the master hologram with light from each of the first light source and the second light source. The wavelength-selective hologram manufacturing apparatus exposes the photosensitive material layer corresponding to the interference fringes between the first lights composed of a plurality of diffracted lights and the interference fringes between the second lights composed of a plurality of diffracted lights.

  Preferably, in the master hologram, the diffraction efficiencies of the first light and the second light generated by the master hologram correspond to the outputs of the first light source and the second light source, respectively.

  According to the present invention, a hologram can be clearly multiplexed and recorded.

It is a conceptual diagram of the manufacturing method of the wavelength selective hologram which concerns on Embodiment 1 of this invention. It is a figure which shows typically the state in which interference light injects into a hologram substrate. It is a figure which shows typically the polymerization reaction which occurs in a photopolymer. It is a figure which shows typically the state which superposition | polymerization reaction was complete | finished in the photopolymer. It is a figure which shows the state which is reproducing | regenerating the wavelength selective hologram with 1st reference light. It is a figure which shows the state which is reproducing | regenerating the wavelength selective hologram with 2nd reference light. In a comparative example, it is a figure which shows the state which entered the 1st light in the hologram substrate. In a comparative example, it is a figure which shows the state which entered the 2nd light in the hologram substrate. It is a figure which shows the sensitivity curve with respect to 1st light and 2nd light of the photosensitive material layer of the embodiment. It is a figure explaining the structure of the preparation apparatus of the wavelength selective hologram which concerns on the same embodiment. It is a conceptual diagram of the preparation method of the wavelength selective hologram which concerns on Embodiment 2 of this invention. It is a figure explaining the structure of the preparation apparatus of the wavelength selective hologram which concerns on Embodiment 3 of this invention.

  Hereinafter, a wavelength selective hologram manufacturing method and a wavelength selective hologram manufacturing apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

Embodiment 1
In the present embodiment, a method for recording a wavelength selective hologram using reproduction light from a master hologram will be described. However, the method for recording a wavelength selective hologram is not limited to this, as in Embodiment 3 described later. A method that does not use a master hologram can be used.

  FIG. 1 is a conceptual diagram of a method for producing a wavelength selective hologram according to Embodiment 1 of the present invention. As shown in FIG. 1, in the present embodiment, a first light source (not shown) that emits light 150 having a wavelength near 405 nm as a first wavelength, and light 160 having a wavelength near 640 nm as a second wavelength. A second light source (not shown) that emits light is used.

  As will be described later, in order to record the wavelength selective hologram 130 on the photosensitive material layer 120, the master hologram 140 is used. In the master hologram 140, a hologram is recorded so that light irradiated from one direction is diffracted in a plurality of directions. In FIG. 1, for the sake of simplicity, two diffracted lights are generated for each light irradiated on the master hologram 140. This diffracted light is reproduction light by the master hologram 140.

  When the master hologram 140 is irradiated with the light 150 and the light 160 from one direction, first light 151 and 152 that are diffracted light of the light 150 and second light 161 and 162 that are diffracted light of the light 160 are generated. The first light 151 and the second light 161 are focused lights that converge at the same position, and are incident on the photosensitive material layer 120 at the same incident angle. The first light 152 and the second light 162 are focused lights that converge at the same position, and are incident on the photosensitive material layer 120 at the same incident angle.

  The master hologram 140 is formed of a material that is sensitive to the first light 151, 152 and the second light 161, 162. Since the master hologram 140 preferably has a high diffraction efficiency, the material for the master hologram 140 is preferably a material having a large refractive index modulation by exposure.

  The photosensitive material layer 120 is formed on the transparent substrate 110 to produce the hologram substrate 100. As the photosensitive material layer 120, a photopolymer is used. When a photopolymer is irradiated with light of a specific wavelength, it is polymerized according to the intensity of the received light. In the photopolymer that has received the interference light, it is exposed and polymerized corresponding to the brightness and darkness of the interference fringes, so that a difference in refractive index occurs between the polymerized part and the non-polymerized part. The refractive index difference generated in the photopolymer is recorded on the hologram recording medium as a hologram.

  The photosensitive material layer 120 is sensitive to the first light 151 and 152 and the second light 161 and 162. The photosensitive material layer 120 is preferably formed of a highly sensitive material with a short exposure time in order to reduce the recording of noise holograms due to vibration during exposure or air fluctuation.

  In addition, when oxygen exists around the photosensitive material layer 120, polymerization of the photopolymer is inhibited. Therefore, a transparent substrate or a transparent film that blocks oxygen is provided on the photosensitive material layer 120. The photosensitive material layer 120 may be formed of the same material as the master hologram 140.

  When the master hologram 140 is irradiated with the lights 150 and 160 simultaneously, the first light 151 and 152 and the second light 161 and 162 are generated simultaneously. The generated first light 151 and the first light 152 expose the photosensitive material layer 120 while interfering with each other in the photosensitive material layer 120. What is the generated second light 161 and second light 162? The photosensitive material layer 120 is exposed while interfering with each other in the photosensitive material layer 120. As a result, holograms are simultaneously multiplexed and recorded in the photosensitive material layer 120 to produce the wavelength selective hologram 130.

  Hereinafter, a reaction that occurs in the photopolymer when a hologram is recorded on the hologram recording medium will be described.

  FIG. 2 is a diagram schematically illustrating a state in which interference light is incident on the hologram substrate. As shown in FIG. 2, the interference light 200 has a bright part 210 with a high light intensity and a dark part 220 with a low light intensity.

  In the hologram substrate 100, a photopolymer 170 constituting the photosensitive material layer 120 is formed on the transparent substrate 110, and the photopolymer 170 includes a monomer 180. The surface of the photopolymer 170 is covered with a transparent film 190.

  FIG. 3 is a diagram schematically showing a polymerization reaction that occurs in the photopolymer. As shown in FIG. 3, when the photopolymer 170 is exposed to interference light, the polymerization reaction starts while consuming the monomer 180 in the portion 230 where the light intensity is strong. In the light intensity portion 240, the monomer 180 moves so as to diffuse into the light intensity portion 230 where the monomer 180 is consumed and the concentration of the monomer 180 is low, as indicated by the arrows in FIG. To do.

  FIG. 4 is a diagram schematically showing a state in which the polymerization reaction is completed in the photopolymer. As shown in FIG. 4, when the exposure is completed, the photopolymer 170 has a high-refractive region 231 in which the monomer 180 is concentrated due to a polymerization reaction and the monomer 180 has a high concentration, and a low-refractive index region 241 in which the monomer 180 has a low concentration. And are formed. As described above, the photosensitive material layer 120 is exposed corresponding to the interference fringes of the interference light. As a result, a hologram based on the refractive index difference is recorded on the hologram substrate 100.

The hologram recorded in this way is called a volume hologram. In order to reproduce the recorded volume hologram, it is necessary to satisfy the Bragg conditions represented by the following formulas (1) and (2).
2 dsin θ _B = mλ (1)
Here, d is an interval between interference fringes, θ _B is a Bragg angle, λ is a wavelength of incident light, and m is an integer.
d = λ / 2n | sin (θ _S −θ _R / 2) | (2)
Here, n is the refractive index of the photosensitive material, θ _S is the incident angle of the signal light to the photosensitive material layer, and θ _R is the incident angle of the reference light to the photosensitive material layer.

For example, when the distance d ₁ between the interference fringes of the first light having the first wavelength λ ₁ of 405 nm is 564 nm, the Bragg angle is used to reproduce the hologram recorded by the first light with the reference light having the wavelength λ _1. must be incident wavelength lambda ₁ of the reference light to the photosensitive material layer by 21.1 ° is theta _B.

In order to reproduce this hologram with reference light having the second wavelength λ ₂ of 640 nm, it is necessary to make the reference light having the wavelength λ ₂ incident on the photosensitive material layer at a Bragg angle θ _B of 34.6 °. Therefore, when the reference light of wavelength λ ₂ is incident on the photosensitive material layer at an incident angle of 21.1 °, the reference light of wavelength λ ₂ is not diffracted by the hologram and the hologram cannot be reproduced. As described above, when the reference lights having different wavelengths are made incident at the same incident angle, only the reference light having a specific wavelength is diffracted by the hologram, and the hologram can be reproduced. This is a so-called wavelength selective hologram.

In the present embodiment, the first light 151, 152 and the second light 161, 162 reproduced by the master hologram 140 are focused lights, and the wavelength selective hologram 130 is produced by causing the focused lights to interfere with each other. . Since the hologram is recorded by the interference between the focused lights, θ _S and θ _R are not constant under the above Bragg conditions, and the conditions of the reference light for reproducing the hologram are limited. The hologram can be reproduced only with reference light that matches the conditions in the vicinity of the wavelength and the incident angle.

  FIG. 5 is a diagram illustrating a state in which the wavelength selective hologram is reproduced with the first reference light. FIG. 6 is a diagram illustrating a state in which the wavelength selective hologram is reproduced with the second reference light.

  As shown in FIGS. 5 and 6, a wavelength selective hologram 130 including a first hologram 131 and a second hologram 132 is formed on the photosensitive material layer 120. The first hologram 131 is recorded corresponding to the interference fringes of the first light 151 and the first light 152 shown in FIG. The second hologram 132 is recorded corresponding to the interference fringes of the second light 161 and the second light 162.

  As shown in FIG. 5, when the reference light 250 having the same wavefront as the first light 151 used for recording the wavelength selective hologram 130 is incident on the wavelength selective hologram 130, the reference light incident on the first hologram 131. 250 is diffracted and becomes reproduction light 251. Of the reference light 250, light that is not incident on the first hologram 131 is transmitted through the wavelength selective hologram 130 without being diffracted to become transmitted light 252.

  As shown in FIG. 6, when the reference light 260 having the same wavefront as the second light 161 used for recording the wavelength selective hologram 130 is incident on the wavelength selective hologram 130, the reference light incident on the second hologram 132. 260 is diffracted and becomes reproduction light 261. Of the reference light 260, light that has not entered the second hologram 132 is transmitted through the wavelength selective hologram 130 without being diffracted, and becomes transmitted light 262.

  Here, as a comparative example, a description will be given of a case where a hologram is multiplexed and recorded by making the first light and the second light enter the photosensitive material layer with a time difference when producing a wavelength selective hologram.

  FIG. 7 is a diagram illustrating a state in which the first light is incident on the hologram substrate in the comparative example. FIG. 8 is a diagram illustrating a state in which the second light is incident on the hologram substrate in the comparative example.

  As shown in FIG. 7, in the comparative example, a first hologram 400 and a first beam 410, which are two diffracted beams, are obtained by irradiating a master hologram (not shown) with a first wavelength. As shown in FIG. 8, in the comparative example, a second hologram 420 and a second beam 430 which are two diffracted beams are obtained by irradiating a master hologram (not shown) with a second wavelength.

  As shown in FIGS. 7 and 8, a photosensitive material layer 320 is formed on a transparent substrate 310 to produce a hologram substrate 300. The photosensitive material layer 320 is sensitive to the first light 400 and 410 and the second light 420 and 430.

  In the comparative example, first, the first light 400 and the first light 410 are incident on the photosensitive material layer 320 as shown in FIG. The first light 400 and the first light 410 expose the photosensitive material layer 320 while interfering with each other in the photosensitive material layer 320. As a result, the first hologram 330 is recorded in the photosensitive material layer 320.

  Next, as shown in FIG. 8, the second light 420 and the second light 430 are incident on the photosensitive material layer 320. At this time, the first hologram 330 is recorded in the photosensitive material layer 320, and a difference in refractive index is generated in the photopolymer constituting the photosensitive material layer 320. In the photopolymer, the polymerization reaction proceeds in accordance with the brightness of the interference fringes, and the molecular size is different between the portion where the polymerization reaction has progressed and the other portion.

  Therefore, the second light 420 and the second light 430 incident on the photosensitive material layer 320 are affected by the difference in the refractive index and the molecular size of the photopolymer, and as shown in FIG. Scattered when transmitted.

  When passing through the photosensitive material layer 320, the second light 420 becomes transmitted light 421 transmitted through the first hologram 330 and scattered light 422, 423 scattered by the first hologram. When passing through the photosensitive material layer 320, the second light 430 becomes transmitted light 431 that has passed through the first hologram 330 and scattered light 432 and 433 scattered by the first hologram. The second light 420 and the second light 430 have wavefront distortion when passing through the photosensitive material layer 320.

  Therefore, when the photosensitive material layer 320 is exposed while the second light 420 and the second light 430 interfere with each other in the photosensitive material layer 320, the exposure cannot be performed corresponding to a desired interference fringe. Since light scattering increases in proportion to the refractive index difference, particularly when recording a first hologram with high diffraction efficiency, it is affected by light scattering particularly when recording a second hologram.

  As described above, when a hologram is recorded on the hologram substrate using diffracted light obtained by separately reproducing the holograms multiplexed and recorded on the master hologram, the accuracy of the hologram recorded later is lowered. As a result, when the produced wavelength selective hologram is reproduced, an extreme deformation is recognized in the beam shape of the reproduced light of the hologram recorded later, or the reproduced light of the hologram recorded later is condensed. The problem of not condensing light at the position occurs.

  The above problem also occurs when the exposure times for recording the first hologram and the second hologram are different. Assume that the exposure time required for recording is longer for the second hologram than for the first hologram. In that case, even if the exposure for recording the first hologram and the exposure for recording the second hologram are started simultaneously, the first hologram is recorded first. For this reason, the second light incident after the completion of the first hologram recording is affected by the first hologram and causes deterioration or scattering of the wavefront. As a result, there is a problem that the accuracy of the second hologram to be recorded is lowered, or the light energy necessary for exposure is insufficient due to light scattering, so that the exposure time is prolonged.

  In the present embodiment, when recording the wavelength selective hologram 130, the first light 151, 152 and the second light 161, 162 are simultaneously incident on the photosensitive material layer 120, and the exposure time by the first light 151, 152 is reached. The wavelength selective hologram 130 including the first hologram 131 and the second hologram 132 is recorded on the photosensitive material layer 120 with the same exposure time with the second light 161 and 162. By doing so, the first light 151, 152 and the second light 161, 162 can interfere with each other while maintaining a good wavefront state, and the desired wavelength selective hologram 130 can be recorded.

  Here, a method for making the exposure time for recording the first hologram and the second hologram the same will be described.

  In the present embodiment, by simultaneously irradiating the master hologram 140 with the light 150 having the first wavelength and the light 160 having the second wavelength, the first light 151, 152 and the second light 161, 162 are simultaneously applied. Is generated. Therefore, in order to make the exposure time for recording the first hologram 131 and the second hologram 132 the same, the diffraction efficiencies of the first light 151, 152 and the second light 161, 162, which are diffracted lights, are set to be the same. It is necessary to correspond to the sensitivity of the photosensitive material layer 120 with respect to each light.

  The sensitivity characteristic of the photosensitive material layer 120 can be controlled by adjusting the addition amount of the photoinitiator and the dye contained in the photosensitive material layer 120. In general, the sensitivity to light of different wavelengths is the same. It is difficult to make. In particular, the sensitivity to light in the long wavelength region is often lower than the sensitivity to light in the low wavelength region.

  FIG. 9 is a diagram showing sensitivity curves for the first light and the second light of the photosensitive material layer of the present embodiment. In FIG. 9, the vertical axis indicates the diffraction efficiency η of the hologram recorded, and the horizontal axis indicates the exposure amount E of the first light or the second light. The sensitivity curve of the first light is indicated by a solid line, and the sensitivity curve of the second light is indicated by a dotted line.

As shown in FIG. 9, when recording a hologram with diffraction efficiency η ₁ , the required exposure amount of the first light having the first wavelength is E ₁ [mJ / cm ² ], and the second exposure having the second wavelength. The required exposure amount of light is E ₂ [mJ / cm ² ]. Since the exposure dose E [mJ / cm ² ] is determined by the exposure power density P [mW / cm ² ] × exposure time t [seconds], the first light exposure time and the second light exposure time t [seconds]. ] To be the same, it is necessary to adjust the diffraction efficiency of the master hologram for reproducing the first light and the second light.

  For example, the exposure time is set to 2 seconds in order to reduce the influence of vibration or air fluctuation during exposure, and the exposure amount necessary to record the wavelength selective hologram 130 having a diffraction efficiency η of 10% is set. Obtained from the sensitivity curve.

First, the amount of exposure required for the non-photosensitive region caused by the inhibition of exposure by oxygen that occurs at the beginning of the sensitivity curve is obtained. In the first light, the amount of exposure required for the non-photosensitive area is E ₁ '. In the second light, the exposure amount required for the non-photosensitive area is E ₂ '.

In order to actually record a hologram by removing the exposure amounts E ₁ ′ and E ₂ ′ required for the non-photosensitive region from the exposure amounts E ₁ and E ₂ required for recording the wavelength selective hologram 130. Calculate the required exposure. In the first light, E ₁ −E ₁ ′ = 10 mJ / cm ² , and in the second light, E ₂ −E ₂ ′ = 18 mJ / cm ² .

The diffraction power efficiency of each of the first lights 151 and 152 of the master hologram, assuming that the incident power densities of the light 150 and the light 160 incident on the master hologram, which are outputs of the first light source and the second light source, are 10 mW / cm ^2. η _M1 was set to 25%, and the diffraction efficiency η _M2 of each of the second lights 161 and 162 was set to 45%.

By doing so, the exposure time t [second] of the first light 151, 152 and the second light 161, 162 is made the same, and the wavelength selective hologram 130 having the desired diffraction efficiency η is recorded. An exposure amount E [mJ / cm ² ] can be given to the photosensitive material layer 120.

Next, the wavelength selective hologram manufacturing apparatus of the present embodiment will be described.
FIG. 10 is a diagram illustrating a configuration of a wavelength selective hologram manufacturing apparatus according to the present embodiment. As shown in FIG. 10, in the wavelength selective hologram manufacturing apparatus 500 according to the present embodiment, as a first light source that emits light of a first wavelength, a single mode LD (Laser Diode) 510 having a wavelength of 405 nm, A single mode LD 520 having a wavelength of 640 nm was used as a second light source that emits light of the second wavelength. The light oscillated from the LD 510 and the LD 520 is adjusted by a wave plate and a polarizer (not shown) so as to be P-polarized light or S-polarized light.

  The light 511 emitted from the LD 510 and the light 521 emitted from the LD 520 are incident on the wavelength selection mirror 530 which is an optical axis adjusting unit on which the multilayer dielectric film is formed, and are emitted with the optical axes aligned. Lights 511 and 521 whose optical axes are aligned pass through a spatial filter 550 for improving beam quality after passing through a shutter 540 that is an exposure adjusting unit that simultaneously adjusts the respective exposure times.

  The lights 511 and 521 are collimated by the collimator lens 560, reflected by the mirror 570, and applied to the master hologram 580. The light 511 is diffracted by the master hologram 580, whereby the first light 512 and the first light 513 are generated. The light 521 is diffracted by the master hologram 580, whereby the second light 522 and the second light 523 are generated.

  The generated first light 512 and second light 522 are simultaneously incident on the photosensitive material layer 590 at the same incident angle. The generated first light 513 and second light 523 are simultaneously incident on the photosensitive material layer 590 at the same incident angle. Therefore, the master hologram 580 serves as an incident direction adjustment unit that causes the first light 512, 513 and the second light 522, 523 to enter the photosensitive material layer 590 from the same direction.

  When the first light 512 and the second light 522 interfere with each other in the photosensitive material layer 590, the first hologram is recorded, and the first light 513 and the second light 523 interfere with each other in the photosensitive material layer 590. Thus, the second hologram is recorded. As a result, the wavelength selective hologram 591 is recorded on the photosensitive material layer 590.

  In the present embodiment, a substrate (not shown) on which a multilayer film is formed is inserted between the master hologram 580 and the photosensitive material layer 590. This substrate transmits the first light 512, 513 and the second light 522, 523, and reflects the light 511, 521 that has passed through the master hologram 580 without being diffracted.

  With the wavelength selective hologram manufacturing apparatus having the above-described configuration, the first light and the second light can be simultaneously incident on the photosensitive material layer 590 at the same incident angle, and the exposure time by the first light The exposure time by the second light can be made the same by the shutter 540. Therefore, the hologram can be clearly multiplexed and recorded. Further, by making the incident direction of the light used for recording the same, it is possible to reduce the number of parts by sharing the optical parts, so that the manufacturing cost of the wavelength selective hologram can be reduced. Furthermore, since the exposure with the first light and the second light is performed simultaneously, the exposure time can be shortened compared to the case where the exposure is performed separately, and the manufacturing tact of the wavelength selective hologram can be shortened. In addition, since the drive portion of the optical system is reduced, the occurrence of vibration during exposure can be reduced, so that the occurrence of defects during hologram recording can be suppressed and the productivity of wavelength selective holograms can be improved.

Hereinafter, a method of creating a wavelength selective hologram according to Embodiment 2 of the present invention will be described.
Embodiment 2
This embodiment is different from Embodiment 1 only in that the photosensitive material layer has a laminated structure of two layers. Since other configurations are the same as those in the first embodiment, description thereof will not be repeated.

  FIG. 11 is a conceptual diagram of a method for producing a wavelength selective hologram according to Embodiment 2 of the present invention. As shown in FIG. 11, the hologram substrate 600 of the present embodiment is formed on a transparent substrate 610 with a photosensitive material layer 620 that is sensitive to the first wavelength light 650 and the second wavelength light 660. A photosensitive material layer 621 that is sensitive to light is formed. The photosensitive material layers 620 and 621 are made of a photopolymer.

  By irradiating the master hologram 640 with light 650 having a wavelength of 405 nm, first light 651 and first light 652 that are diffracted light are generated. When the master hologram 640 is irradiated with light 660 having a wavelength of 640 nm, second light 661 and second light 662 that are diffracted light are generated.

  The first light 651 and the first light 652 pass through the photosensitive material layer 621 and interfere in the photosensitive material layer 620 to record the first hologram 630. The second light 661 and the second light 662 interfere with each other in the photosensitive material layer 621 to record the second hologram 631 and pass through the photosensitive material layer 620. Thus, in this embodiment, the wavelength selective hologram is comprised from the 1st hologram 630 and the 2nd hologram 631 which were formed in a different layer.

  In this embodiment, although formed on the photosensitive material layer 621 and the photosensitive material layer 620, the stacking order is the transmittance of the first light 651, 652 in the photosensitive material layer 621 and the second light 661, 662. It is preferable to be determined by the relationship with the transmittance in the photosensitive material layer 620. That is, by forming the photosensitive material layer having a high transmittance above the photosensitive material layer having a low transmittance, the reduction in the exposure power density P of the first light or the second light can be suppressed.

  Also in the present embodiment, the first light 651, 652 and the second light 661, 662 are incident on the photosensitive material layers 620, 621 at substantially the same incident angle at the same time, and the exposure time by the first light 651, 652; Holograms can be recorded on the photosensitive material layers 620 and 621 with the same exposure time with the second light 661 and 662. Therefore, since the photosensitive material layers 620 and 621 can be exposed while maintaining the accuracy of the wavefronts of the first light 651 and 652 and the second light 661 and 662, a high-quality wavelength selective hologram is recorded. be able to.

  Further, in the present embodiment, the photosensitive material layers 620 and 621 have a two-layered structure, and therefore, in each layer, the photosensitive material material M number (multiplex recording is performed) is optimized for each light wavelength. It is possible to determine characteristics such as the sum of the square roots of the diffraction efficiencies when performed, sensitivity, shrinkage, and transmittance, and to enhance the characteristics of the wavelength selective hologram recorded in each layer.

Hereinafter, a wavelength selective hologram manufacturing apparatus according to Embodiment 3 of the present invention will be described.
Embodiment 3
The wavelength selective hologram manufacturing apparatus according to the present embodiment is different from the first embodiment in that a master hologram is not used.

  FIG. 12 is a diagram for explaining the configuration of a wavelength selective hologram manufacturing apparatus according to Embodiment 3 of the present invention. As shown in FIG. 12, in the wavelength selective hologram manufacturing apparatus 700 according to this embodiment, as a first light source that emits light having a first wavelength, a single mode LD 710 having a wavelength of 405 nm, and a second wavelength having a second wavelength. A single mode LD 720 having a wavelength of 640 nm was used as a second light source that emits light. Light oscillated from the LD 710 and the LD 720 is adjusted by a wave plate and a polarizer (not shown) so as to be P-polarized light or S-polarized light.

  The light 711 emitted from the LD 710 and the light 721 emitted from the LD 720 are incident on a wavelength selection mirror 730 which is an optical axis adjusting unit on which a multilayer dielectric film is formed, and are emitted with the optical axes aligned. Lights 711 and 721 whose optical axes are aligned pass through a spatial filter 750 for improving the beam quality after passing through a shutter 740 that is an exposure adjusting unit that simultaneously adjusts the respective exposure times.

  Each of the light 711 and the light 721 is collimated by a collimating lens 760 and then branched into two by a half mirror 770, and one light goes straight and is reflected by a mirror 780 and then converged by a lens 810. Light is incident on the photosensitive material layer 820. The other light is reflected by the half mirror 770, further reflected by the mirror 790, then converged by the lens 800 and incident on the photosensitive material layer 820. The light beams 711 and 721 that have become focused light interfere with each other in the photosensitive material layer 820, and the photosensitive material layer 820 is exposed to record the wavelength selective hologram 830. In the light 711, the half mirror 770, the mirror 790, and the lens 800 serve as an incident direction adjusting unit. In the light 721, the mirror 780 and the lens 810 serve as an incident direction adjusting unit.

  The half mirror 770 is designed to branch light at an intensity ratio such that the power densities of the branched lights incident on the photosensitive material layer 820 are equal. Further, the LDs 710 and 720 have a power control mechanism so that the emission intensity of the light 711 and 721 can be controlled in accordance with the sensitivity of the photosensitive material with respect to the light 711 having the first wavelength and the light 721 having the second wavelength. Is provided.

  Also in the wavelength selective hologram manufacturing apparatus of this embodiment, the light 711 and the light 721 are simultaneously incident on the photosensitive material layer 820 at the same incident angle, and the exposure time by the light 711 and the exposure time by the light 721 are calculated. In the same manner, multiple holograms can be recorded on the photosensitive material layer 820.

  In this embodiment, it is possible to produce a wavelength-selective hologram with stable quality without producing a master hologram. Therefore, in the wavelength selective hologram that does not particularly require a complicated pattern, the master hologram production process can be reduced.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It does not become a basis of limited interpretation. Therefore, the technical scope of the present invention is not interpreted only by the above-described embodiments, but is defined based on the description of the scope of claims. Further, all modifications within the meaning and scope equivalent to the scope of the claims are included.

  100, 300, 600 Hologram substrate, 110, 310, 610 Transparent substrate, 120, 320, 590, 620, 621, 820 Photosensitive material layer, 130, 591, 830 Wavelength selective hologram, 131, 330, 630 First hologram 132, 631 2nd hologram, 140, 580, 640 Master hologram, 150, 511, 650, 711 Light having a first wavelength, 160, 521, 660, 721 Light having a second wavelength, 151, 152, 400, 410, 512, 513, 651, 652 first light, 161, 162, 420, 430, 522, 523, 661, 662 second light, 170 photopolymer, 180 monomer, 190 transparent film, 200 interference light, 210 Bright part, 220 Dark part, 230 High light intensity part 240 Light weak part, 231 High refractive region, 241 Low refractive index region, 250, 260 Reference light, 251, 261 Reproduction light, 252, 262, 421, 431 Transmitted light, 422, 423, 432, 433 Scattered light, 500,700 Wavelength selective hologram production apparatus, 530,730 Wavelength selection mirror, 540,740 Shutter, 550,750 Spatial filter, 560,760 Collimating lens, 570,780,790 Mirror, 770 Half mirror, 800,810 Lens .

Claims (6)

When the first light having the first wavelength and the second light having a second wavelength different from the first wavelength are caused to interfere with each other in the photosensitive material layer, the first light is diffracted and the first light is diffracted. A method for producing a wavelength selective hologram, comprising: a first hologram that transmits two lights without diffracting; and a second hologram that diffracts the second light and transmits the first light without diffracting. ,
Forming a layer of the photosensitive material that is sensitive to the first light and the second light; and
The first light and the second light are simultaneously incident on the photosensitive material layer at the same incident angle so that the exposure time by the first light and the exposure time by the second light are the same, And a recording step of recording a hologram including the hologram and the second hologram on the photosensitive material layer. The first light and the second light are irradiated with light having the first wavelength and light having the second wavelength, so that the light having the first wavelength and the second wavelength are changed. A master hologram that generates a plurality of diffracted lights for each of the light beams is generated by irradiating the light beam having the first wavelength and the light beam having the second wavelength,
The photosensitive material layer is exposed by causing the first light consisting of a plurality of diffracted lights to interfere with each other and the second light consisting of a plurality of diffracted lights to interfere with each other in the recording step. 2. A method for producing a wavelength selective hologram according to 1.   As the master hologram, the diffraction efficiency of each of the first light and the second light generated by the master hologram is applied to the master hologram having the wavelength of each of the first light and the second light. The method for producing a wavelength selective hologram according to claim 2, wherein a recorded hologram is used so as to correspond to each output of light. When the first light having the first wavelength and the second light having a second wavelength different from the first wavelength are caused to interfere with each other in the photosensitive material layer, the first light is diffracted and the first light is diffracted. An apparatus for producing a wavelength selective hologram, comprising: a first hologram that transmits two light beams; and a second hologram that diffracts the second light and transmits the first light beam,
A first light source that emits light having the first wavelength;
A second light source that emits light having the second wavelength;
An optical axis adjustment unit that aligns the optical axes of the light emitted from the first light source and the light emitted from the second light source;
An incident direction adjusting unit for causing the first light and the second light to enter the photosensitive material layer from the same direction;
An apparatus for producing a wavelength selective hologram, comprising: an exposure adjusting unit that simultaneously adjusts an exposure time of the photosensitive material layer by the first light and the second light. A master hologram that generates a plurality of diffracted lights in each of the light having the first wavelength and the light having the second wavelength by being irradiated with light from the first light source and the second light source;
The first light and the second light are generated by irradiating the master hologram with light from each of the first light source and the second light source,
The said photosensitive material layer is exposed corresponding to the interference fringe of said 1st lights which consist of several diffracted lights, and the interference fringe of said 2nd lights which consist of several diffracted lights. An apparatus for producing a wavelength selective hologram.   In the master hologram, diffraction efficiency of each of the first light and the second light generated by the master hologram corresponds to an output of each of the first light source and the second light source. 6. A device for producing a wavelength-selective hologram according to 5.

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