CN114089459A

CN114089459A - Volume holographic grating manufacturing device, volume holographic optical waveguide and manufacturing method and application thereof

Info

Publication number: CN114089459A
Application number: CN202210067767.0A
Authority: CN
Inventors: 罗润秋; 杨鑫; 宋强; 马国斌
Original assignee: Long Optoelectronics Co ltd
Current assignee: Long Optoelectronics Co ltd
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2022-02-25

Abstract

The embodiment of the invention provides a volume holographic grating manufacturing device, a volume holographic optical waveguide, a manufacturing method and application thereof, wherein the manufacturing device comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a volume holographic film and at least one gradual change attenuation sheet, or the manufacturing device comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a second prism, a volume holographic film and at least one gradual change attenuation sheet; the manufacturing device is simple and high in yield, and meanwhile, the volume holographic optical waveguide can be manufactured by cutting the exposed volume holographic film, large-scale mass production can be realized by the mode, the production efficiency is improved, and the manufactured volume holographic optical waveguide is applied to near-to-eye display equipment and can realize a large field angle and a large eye movement range.

Description

Volume holographic grating manufacturing device, volume holographic optical waveguide and manufacturing method and application thereof

Technical Field

The embodiment of the invention relates to the technical field of optics, in particular to a volume holographic grating manufacturing device, a volume holographic optical waveguide, a manufacturing method and application thereof.

Background

Among optical display devices, the augmented reality technology, which is a technology for projecting a real world and a virtual world in a superimposed manner to the eyes of users, is of great significance in the fields of military affairs, industry, education, entertainment, transportation, and the like.

Because the manufacturing process difficulty and the manufacturing cost of the array optical waveguide and the relief grating waveguide are high, the volume holographic optical waveguide is often adopted as a key display device for augmented reality. Among the volume holographic optical waveguides, the two-dimensional pupil-expanding volume holographic optical waveguide is a research hotspot in recent years, and consists of an incoupling grating, a turning grating, an outcoupling grating and a waveguide substrate.

For two-dimensional pupil-expanding volume holographic optical waveguides, they are typically fabricated by holographic dry plate exposure. Due to the optical sensitivity of the coating type holographic dry plate material, the grating structures of the coupling-in part, the turning part and the coupling-out part need to be exposed at one time under the dark room condition, so that the light path is complex to manufacture; in addition, the complex manufacturing optical path and the contingency of experiments also result in low yield and failure to realize industrialized large-scale mass production.

Disclosure of Invention

The embodiment of the invention provides a volume holographic grating manufacturing device, a volume holographic optical waveguide, a manufacturing method and application thereof, the manufacturing device is simple and high in yield, meanwhile, the volume holographic optical waveguide can be manufactured by cutting an exposed volume holographic film and attaching the film to a corresponding area of a waveguide substrate, large-scale mass production can be realized by the method, the production efficiency is improved, and the manufactured volume holographic optical waveguide can be applied to near-eye display equipment and can realize a large field angle and a large eye movement range.

In a first aspect, one technical solution adopted in the embodiments of the present invention is: there is provided a volume hologram grating manufacturing apparatus, including: the holographic volume holographic film comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a volume holographic film and at least one gradual change attenuation sheet; the light-emitting side of the laser light source is provided with a light-emitting side of the light-splitting unit, and the light-splitting unit is used for splitting light of the laser light source into a first light beam emitted from a first light-emitting side of the light-splitting unit and a second light beam emitted from a second light-emitting side of the light-splitting unit; the first reflection unit is arranged on the first light-emitting side, the first side of the volume holographic film is arranged on the light-emitting side of the first reflection unit, and the first reflection unit is used for emitting the first light beam to the volume holographic film; the second reflection unit is arranged on the second light-emitting side, the first side of the first prism is arranged on the light-emitting side of the second reflection unit, the second side of the volume holographic film is arranged on the second side of the first prism, the second reflection unit is used for emitting the second light beam to the first side of the first prism, and the first prism is used for receiving the second light beam through the first side of the first prism and emitting the second light beam to the volume holographic film through the second side of the first prism; the gradual attenuation sheet is arranged in the light path of the first light beam and is used for modulating the transmissivity of the first light beam, and/or is arranged in the light path of the second light beam and is used for modulating the transmissivity of the second light beam; the volume holographic film is used for being subjected to interference exposure by the first light beam and the second light beam to form the volume holographic grating.

In some embodiments, the first reflecting unit includes a first mirror; the first reflector is arranged on the first light-emitting side, and the first side of the volume holographic film is arranged in the reflection direction of the first reflector.

In some embodiments, the second reflecting unit comprises a second mirror and a third mirror; the second reflector is arranged on the second light-emitting side, the third reflector is arranged on the reflecting direction of the second reflector, and the first side of the first prism is arranged on the reflecting direction of the third reflector.

In some embodiments, the third reflector is disposed on the slide rotation stage.

In some embodiments, the laser light source comprises a beam combiner and at least one laser; each laser is respectively arranged at each input end of the beam combiner, and the light incident side of the light splitting unit is arranged at the output end of the beam combiner.

In a second aspect, an embodiment of the present invention further provides a device for manufacturing a volume holographic grating, where the device includes: the holographic film holographic laser comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a second prism, a volume holographic film and at least one gradual change attenuation sheet; the light-emitting side of the laser light source is provided with a light-emitting side of the light-splitting unit, and the light-splitting unit is used for splitting light of the laser light source into a first light beam emitted from a first light-emitting side of the light-splitting unit and a second light beam emitted from a second light-emitting side of the light-splitting unit; the first reflection unit is arranged on the first light-emitting side, the first side of the second prism is arranged on the light-emitting side of the first reflection unit, the first side of the volume holographic film is arranged on the second side of the second prism, the first reflection unit is used for emitting the first light beam to the first side of the second prism, and the second prism is used for receiving the first light beam through the first side of the second prism and emitting the first light beam to the volume holographic film through the second side of the second prism; the second reflection unit is arranged on the second light-emitting side, the first side of the first prism is arranged on the light-emitting side of the second reflection unit, the second side of the volume holographic film is arranged on the second side of the first prism, the second reflection unit is used for emitting the second light beam to the first side of the first prism, and the first prism is used for receiving the second light beam through the first side of the first prism and emitting the second light beam to the volume holographic film through the second side of the first prism; the gradual attenuation sheet is arranged in the light path of the first light beam and is used for modulating the transmissivity of the first light beam, and/or is arranged in the light path of the second light beam and is used for modulating the transmissivity of the second light beam; the volume holographic film is used for being subjected to interference exposure by the first light beam and the second light beam to form the volume holographic grating.

In some embodiments, the first reflecting unit includes a first mirror; the first reflector is arranged on the first light-emitting side, and the first side of the second prism is arranged in the reflection direction of the first reflector.

In some embodiments, the first mirror is disposed on the first track rotation stage, and/or the third mirror is disposed on the second track rotation stage.

In a third aspect, an embodiment of the present invention further provides a method for manufacturing a volume holographic optical waveguide, including: obtaining a first integral holographic grating by the manufacturing device according to any one of the first aspect, and cutting the first integral holographic grating to obtain an incoupling grating and/or an outcoupling grating; and/or obtaining a second volume holographic grating by the manufacturing device according to any one of the second aspect, and cutting the second volume holographic grating to obtain a turning grating; providing a transparent substrate, wherein the transparent substrate comprises a first area, a second area and a third area; will one the coupling grating laminating sets up the first region, will one the coupling grating laminating sets up the second region, will one the turning grating laminating sets up the third region, perhaps, will be a plurality of the coupling grating stacks the laminating setting in proper order and is in the first region, will be a plurality of the coupling grating stacks the laminating setting in proper order and is in the second region, will be a plurality of the turning grating stacks the laminating setting in proper order and is in the third region, thereby obtains the volume holographic optical waveguide.

In a fourth aspect, embodiments of the present invention further provide a volume holographic optical waveguide, which is manufactured by the manufacturing method of the third aspect.

In some embodiments, the volume holographic optical waveguide is an angle-multiplexed and/or wavelength-multiplexed volume holographic optical waveguide.

In a fifth aspect, embodiments of the present invention also provide a near-eye display device comprising a volume holographic optical waveguide according to any of the fourth aspects.

Compared with the prior art, the invention has the beneficial effects that: different from the situation of the prior art, an embodiment of the present invention provides a volume holographic grating manufacturing apparatus, a volume holographic optical waveguide, a manufacturing method thereof, and a near-to-eye display device, where the manufacturing apparatus includes a laser light source, a light splitting unit, a first reflection unit, a second reflection unit, a first prism, a volume holographic film, and at least one gradual attenuation sheet, or the manufacturing apparatus includes a laser light source, a light splitting unit, a first reflection unit, a second reflection unit, a first prism, a second prism, a volume holographic film, and at least one gradual attenuation sheet; the manufacturing device is simple and high in yield, and meanwhile, the exposed volume holographic film is cut and attached to the corresponding area of the waveguide substrate, so that the volume holographic optical waveguide can be manufactured.

Drawings

One or more embodiments are illustrated by the accompanying figures in the drawings that correspond thereto and are not to be construed as limiting the embodiments, wherein elements/modules and steps having the same reference numerals are represented by like elements/modules and steps, unless otherwise specified, and the drawings are not to scale.

FIG. 1 is a schematic structural diagram of an apparatus for manufacturing a volume holographic grating according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of another apparatus for fabricating a volume holographic grating according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a device for manufacturing a volume holographic grating according to an embodiment of the present invention at a first viewing angle;

FIG. 4 is a schematic view of the portion of the structure of FIG. 3 from a second perspective;

FIG. 5 is a schematic view of a portion of the optical path of FIG. 3;

FIG. 6 is a schematic diagram of an apparatus for fabricating a volume holographic grating according to another embodiment of the present invention;

FIG. 7 is a schematic diagram of a cut-out of a first integral holographic grating provided by an embodiment of the present invention;

FIG. 8 is a schematic diagram of a second volume holographic grating according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a volume holographic optical waveguide according to embodiments of the present invention;

FIG. 10 is a schematic structural diagram of another volume holographic optical waveguide provided by embodiments of the present invention.

Description of reference numerals: 10-laser light source, 11-red laser, 12-blue laser, 13-green laser, 14-beam combiner, 15-spatial filter, 16-Fourier collimating lens, 20-beam splitting unit, 31-first reflecting unit, 32-second reflecting unit, 321-second reflecting mirror, 322-third reflecting mirror, 41-second prism, 42-first prism, 50-volume holographic film, 61-first gradual attenuation sheet, 62-second gradual attenuation sheet, 71-first diaphragm, 72-second diaphragm, 80-polarization beam splitting prism, L1-first beam, L2-second beam, 51-first volume holographic grating, 511-incoupling grating, 512-outcoupling grating, 52-second volume holographic grating, 521-turning grating, 200-transparent substrate.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

In order to facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and specific embodiments. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that, if not conflicted, the various features of the embodiments of the invention may be combined with each other within the scope of protection of the present application. In addition, although the functional blocks are divided in the device diagram, in some cases, the blocks may be divided differently from those in the device. Further, the terms "first," "second," and the like, as used herein, do not limit the data and the execution order, but merely distinguish the same items or similar items having substantially the same functions and actions.

In a first aspect, an embodiment of the present invention provides a device for manufacturing a volume holographic grating, please refer to fig. 1, the device includes: the holographic optical system comprises a laser light source 10, a light splitting unit 20, a first reflecting unit 31, a second reflecting unit 32, a first prism 42, a volume holographic film 50 and at least one gradient attenuation sheet.

The light-incident side of the light-splitting unit 20 is disposed at the light-exiting side of the laser light source 10, and the light-splitting unit 20 is configured to split the light of the laser light source 10 into a first light beam L1 exiting from the first light-exiting side of the light-splitting unit 20 and a second light beam L2 exiting from the second light-exiting side of the light-splitting unit 20. The first reflection unit 31 is disposed on the first light outgoing side of the light splitting unit 20, the first side of the volume hologram film 50 is disposed on the light outgoing side of the first reflection unit 31, and the first reflection unit 31 is configured to emit the first light beam L1 to the volume hologram film 50. The second reflection unit 32 is disposed on the second light emitting side of the light splitting unit 20, the first side of the first prism 42 is disposed on the light emitting side of the second reflection unit 32, the second side of the volume hologram film 50 is disposed on the second side of the first prism 42, the second reflection unit 32 is configured to emit the second light beam L2 to the first side of the first prism 42, and the first prism 42 is configured to receive the second light beam L2 through the first side of the first prism 42 and emit the second light beam L2 to the volume hologram film 50 through the second side of the first prism 42. The gradual attenuation sheet is arranged in the optical path of the first light beam L1 and is used for modulating the transmissivity of the first light beam L1, and/or the gradual attenuation sheet is arranged in the optical path of the second light beam L2 and is used for modulating the transmissivity of the second light beam L2. The volume hologram film 50 is configured to be exposed by interference of the first beam L1 and the second beam L2 to form a volume hologram grating.

Specifically, the volume hologram film 50 includes a PET (Polyester) film and a volume hologram material coated on the PET film, wherein the volume hologram material may be silver salt, photopolymer, dichromated gelatin, photorefractive material, photo-anisotropic material, or any other photosensitive material that can be used to record interference fringes after exposure; illustratively, the silver salt can be a silver halide emulsion. Meanwhile, the second side of the volume hologram film 50 is attached to the second side of the first prism 42 by the refractive index matching fluid.

Illustratively, with continued reference to fig. 1, the at least one graduated attenuation piece includes a first graduated attenuation piece 61 and a second graduated attenuation piece 62, the first graduated attenuation piece 61 is disposed between the first reflection unit 31 and the first side of the volume hologram film 50, and the second graduated attenuation piece 62 is disposed between the second reflection unit 32 and the first side of the first prism 42. The attenuation proportion of the gradual attenuation sheet is gradually changed along with displacement, so that the light transmittance of different areas is modulated through the gradual attenuation sheet, the diffraction efficiency is controlled through different exposure amounts of different exposure areas, the finally prepared volume holographic grating has different diffraction efficiency in different areas, and can show certain regular change, and the same energy coupled out every time is ensured.

In the manufacturing apparatus, first, the light beam of the laser light source 10 passes through the light splitting unit 20 and is split into a first light beam L1 and a second light beam L2; then, the first light beam L1 passes through the first reflection unit 31 and the first gradual attenuation sheet 61 and then exits to the first side of the volume holographic film 50, and the second light beam L2 passes through the second reflection unit 32, the second gradual attenuation sheet 62 and the first prism 42 and exits to the second side of the volume holographic film 50; finally, the first light beam L1 and the second light beam L2 interfere on the volume hologram film 50, forming a volume hologram grating. In practical applications, the first gradual attenuation sheet 61 may also be disposed between the first light emitting side of the light splitting unit 20 and the first reflection unit 31, and the second gradual attenuation sheet 62 may also be disposed between the second light emitting side of the light splitting unit 20 and the second reflection unit 32, wherein the number and the positions of the gradual attenuation sheets may be set according to actual needs, and there is no need to limit the number and the positions in this embodiment.

Firstly, the device exposes by using the volume holographic film 50, compared with the holographic plate, the volume holographic film 50 has stronger flexibility and extremely light and thin thickness, so that the volume holographic grating manufacturing process is simpler and more flexible. Secondly, by setting the attenuation proportion of different areas of the first gradual attenuation sheet 61 and/or the second gradual attenuation sheet 62, the light transmittance of the first light beam L1 and/or the second light beam L2 can be changed, and the diffraction efficiency is controlled by controlling the exposure amount, so that the diffraction efficiency of different areas manufactured on the volume holographic film 50 shows a certain rule, and the same energy is ensured to be output every time in the final coupled-out grating, thereby ensuring uniform display brightness. In addition, the manufacturing apparatus is simple in manufacturing optical path and high in yield. Meanwhile, the manufactured volume holographic grating can be used as an in-coupling grating and an out-coupling grating in the volume holographic optical waveguide, and the volume holographic optical waveguide can be manufactured by cutting the manufactured grating and attaching the cut grating to a transparent substrate (such as a glass substrate, a resin substrate and the like).

In other embodiments, a movable baffle can be used to replace a gradual attenuation sheet, and a grating structure with diffraction efficiency in different areas changing regularly can also be manufactured on the volume holographic film. However, when the movable baffle is adopted for manufacturing, light at the edge of the movable baffle can be diffracted, so that stray light can be generated in the exposure process, and the yield is reduced. In order to ensure the yield, the attenuation sheet is usually manufactured.

In the manufacturing process, various volume holographic gratings can be manufactured by changing exposure parameters, wherein the exposure parameters comprise the number of wavelengths of exposure light and exposure angles. The exposure angle includes an incident angle at which the first light beam L1 is incident to the first side of the volume hologram film 50 and an incident angle at which the second light beam L2 is incident to the second side of the volume hologram film 50, and it is understood that the exposure angle may be considered to be different as long as there is a difference in the incident angle of a certain light beam.

Optionally, in the manufacturing process, if the volume holographic film 50 is exposed once at a certain set of exposure angles by using only one wavelength of light, a holographic interference fringe corresponding to the wavelength and the exposure angle of the exposure light is formed on the volume holographic film 50, that is, the volume holographic grating has a periodic refractive index modulation structure corresponding to the wavelength and the exposure angle of the exposure light. The volume holographic grating manufactured by the method can realize diffraction on incident light corresponding to the wavelength of exposure light.

Optionally, if a volume holographic film is exposed simultaneously after only N light beams with different wavelengths are combined, N kinds of holographic interference fringes corresponding to N different wavelengths are formed on the volume holographic film, that is, N kinds of refractive index modulation structures corresponding to N different wavelengths are provided on the manufactured volume holographic grating, so as to obtain a wavelength-multiplexed volume holographic grating, where N is an integer greater than or equal to 2. In the wavelength multiplexing volume holographic grating, for different volume holographic interference fringes formed by N light rays with different wavelengths under the same group of exposure angles, the grating vector directions corresponding to the holographic interference fringes are the same, namely the holographic interference fringes have the same fringe inclination angle. That is, in the volume hologram grating, the refractive index modulation structures having N kinds of fringe periods, respectively, and the fringe inclinations of the N kinds of refractive index modulation structures are the same, and the fringe periods of these hologram interference fringes are wavelength-dependent.

Specifically, when the light beams of red light, green light and blue light are combined and simultaneously exposed, holographic interference fringes obtained by exposing corresponding red light, holographic interference fringes obtained by exposing corresponding green light and holographic interference fringes obtained by exposing corresponding blue light are formed on the volume holographic film 50, that is, three refractive index modulation structures corresponding to red light, green light and blue light are respectively formed on the manufactured volume holographic grating, so that the volume holographic grating with the wavelength multiplexing is obtained, and the wavelength multiplexing of the light beams with the three wavelengths of red light, green light and blue light can be realized. For example, when the incident light is an RGB laser light source, i.e., when the incident light includes red light, green light, and blue light at the same time, the wavelength-multiplexed volume hologram grating can diffract the red light, the green light, and the blue light at the same time. In addition, in the exposure process, the diffraction efficiency of the volume holographic grating to the three-color light beams of red light, green light and blue light can be approximately the same by adjusting the laser energy ratio of the red light, the green light and the blue light, so that the rainbow effect is inhibited.

In the wavelength-multiplexed volume holographic grating, under the same group of exposure angles, the vector directions of the grating corresponding to the holographic interference fringes corresponding to the red light, the holographic interference fringes corresponding to the green light and the holographic interference fringes corresponding to the blue light are the same, namely, the grating vector directions have the same fringe inclination angle, but the corresponding fringe periods are respectively related to the wavelength, namely, the fringe periods among the holographic interference fringes formed by the light exposure of different wavelengths are not equal.

Optionally, in the manufacturing process, if light with the same wavelength is used to perform M exposures on a volume hologram film at M groups of different exposure angles, M types of holographic interference fringes corresponding to the M groups of exposure angles are formed on the obtained volume hologram film. Namely, M holographic interference fringes corresponding to M groups of exposure angles are formed in the prepared volume holographic grating, so that an angle-multiplexed volume holographic grating is obtained, wherein M is an integer greater than or equal to 2.

In the angle-multiplexed volume holographic grating, for M different kinds of holographic interference fringes formed by light rays with the same wavelength under M groups of different exposure angles, the holographic interference fringes have the same fringe period and different fringe inclination angles. For example, the volume holographic film is exposed for three times by using light rays with the same wavelength and three exposure angles, so that three holographic interference fringes corresponding to the three exposure angles are respectively arranged in the obtained volume holographic grating, and the three holographic interference fringes have the same fringe period but different fringe inclination angles.

It can be understood that, for the manufactured angle-multiplexed volume holographic grating, when light with a wavelength corresponding to that used in exposure is incident into the angle-multiplexed volume holographic grating, even if the light is incident into the angle-multiplexed volume holographic grating at a large angle, the angle-multiplexed volume holographic grating still has high diffraction efficiency, and can realize angle multiplexing and good large-field display when being subsequently applied to an optical waveguide.

Optionally, in the manufacturing process, if light beams with different wavelengths are used to expose the volume holographic film at different exposure angles, a volume holographic grating with both angle multiplexing and wavelength multiplexing functions can be obtained. It can be understood that when a light beam composed of N light beams with different wavelengths is used to expose a volume holographic film M times at M groups of different exposure angles, N × M kinds of holographic interference fringes are formed on the volume holographic film, that is, in the manufactured volume holographic grating, N × M kinds of periodic refractive index modulation structures are provided, and by manufacturing the volume holographic grating in this way, a volume holographic grating with both angle multiplexing and wavelength multiplexing can be obtained.

In some embodiments, the light splitting unit 20 includes a light splitter, an incident side of the light splitter is disposed on an emergent side of the laser light source 10, an incident side of the first reflecting unit 31 is disposed on a transmission side of the light splitter, and an incident side of the second reflecting unit 32 is disposed on a reflection side of the light splitter. The beam splitter is used to split the light of the laser light source 10 into transmitted light and reflected light having a certain light intensity ratio. Specifically, the beam splitter may be a coated glass, and a light beam may be split into a plurality of light beams by reflection and transmission after being projected onto the coated glass by coating one or more layers of thin films on the surface of the optical glass. In practical applications, a fixed splitting ratio beam splitter and a variable splitting ratio beam splitter may be selected, and are not limited herein.

In some of the embodiments, the first reflecting unit 31 includes a first mirror; the first mirror is disposed on the first light exit side of the light splitting unit 20, and the first side of the volume hologram film 50 is disposed in the reflection direction of the first mirror. The first mirror is used to reflect the first light beam to a first side of the volume holographic film 50. In practical applications, the number of the reflecting mirrors included in the first reflecting unit 31 can be set according to actual needs, and is not limited in this embodiment.

In some embodiments, referring to fig. 1, the second reflecting unit 32 includes a second reflecting mirror 321 and a third reflecting mirror 322; the second reflecting mirror 321 is disposed on the second light-emitting side of the light-splitting unit 20, the third reflecting mirror 322 is disposed in the reflecting direction of the second reflecting mirror 321, and the first side of the first prism 42 is disposed in the reflecting direction of the third reflecting mirror 322. The second reflecting mirror 321 is used for reflecting the second light beam L2 to the third reflecting mirror 322, and the third reflecting mirror 322 is used for reflecting the second light beam L2 to the first side of the first prism 42. In practical applications, the number and specific positions of the reflectors included in the second reflecting unit 32 can be set according to actual needs, and the second reflecting unit is not limited to the limitations of the present embodiment.

In some embodiments, referring to fig. 2, the third reflector 322 is disposed on the slide track rotating platform. The slide rotation stage can drive the third reflector 322 to translate and rotate. Specifically, the sliding track rotating table can drive the third reflecting mirror 322 to move along the direction parallel to the first side of the volume holographic film 50 on the plane where the sliding track rotating table is located, in addition, the sliding track rotating table can drive the third reflecting mirror 322 to rotate around the center of the third reflecting mirror 322, the sliding track rotating table drives the third reflecting mirror 322 to translate and rotate, the incident angle of the second light beam L2 on the second side of the volume holographic film 50 can be changed (namely, the incident angle of the second light beam L2 from the second side of the volume holographic film 50 is changed), and therefore the volume holographic film 50 can be exposed by the second light beam L2 at different incident angles, and the purpose of changing the exposure angle is achieved.

In some embodiments, the first reflector may also be disposed on the slide rotation stage. The slide rail rotating platform can drive the first reflecting mirror to translate and rotate. Specifically, this slide rail revolving stage can drive first speculum at slide rail revolving stage place plane, move along the direction that is on a parallel with the first side of volume holographic film 50, in addition, this slide rail revolving stage can drive first speculum and rotate around the center of first speculum, drive first speculum through the slide rail revolving stage and carry out translation and rotation, can change the incident angle of first light beam at the first side of volume holographic film 50 (change the angle that first light beam L1 incides from the first side of volume holographic film 50 promptly), thereby can let volume holographic film 50 exposed with different incident angles by first light beam L1.

In practical applications, the plane mirror fixed on the slide rail rotation stage can be freely disposed, and the limitation in the above embodiments is not required. The exposure position and the exposure angle can be changed by fixing the plane mirror which needs to be translated or rotated in the sliding rail rotating table, so that various types of volume holographic gratings can be manufactured.

In some of these embodiments, the laser light source 10 includes a beam combiner 14 and at least one laser; each laser is respectively disposed at each input end of the beam combiner 14, and the light incident side of the light splitting unit 20 is disposed at the output end of the beam combiner 14.

Specifically, in some embodiments, referring to fig. 2, the laser light source 10 may include a red laser 11, a blue laser 12, a green laser 13 and a beam combiner 14, the red laser 11 is disposed at a first input end of the beam combiner 14, the blue laser 12 is disposed at a second input end of the beam combiner 14, the green laser 13 is disposed at a third input end of the beam combiner 14, and an incident light side of the beam splitting unit 20 is disposed at an output end of the beam combiner 14, so that the beam combiner 14 may combine red light emitted by the red laser 11, green light emitted by the green laser 13 and blue light emitted by the blue laser 12 into a laser beam and output the laser beam to the beam splitting unit 20. In practical applications, the arrangement of the lasers and the structure of the beam combiner 14 may be set according to actual needs, and need not be limited to the limitations in this embodiment.

Thus, in the manufacturing device, when the light beams of red light, green light and blue light are combined and exposed simultaneously, holographic interference fringes obtained by exposing corresponding to the red light, holographic interference fringes obtained by exposing corresponding to the green light and holographic interference fringes obtained by exposing corresponding to the blue light are respectively arranged on the volume holographic film 50, that is, three refractive index modulation structures corresponding to the red light, the green light and the blue light are respectively formed on the manufactured volume holographic grating, so that the volume holographic grating with the wavelength multiplexing is obtained, and the wavelength multiplexing of the light beams with the three wavelengths of the red light, the green light and the blue light can be realized. For example, when the incident light is an RGB laser light source, that is, when the incident light includes red light, green light, and blue light at the same time, the wavelength-multiplexed volume holographic grating can diffract the red light, the green light, and the blue light at the same time, thereby realizing full-color display. In addition, in the exposure process, the diffraction efficiency of the volume holographic grating to the three-color light beams of red light, green light and blue light can be approximately the same by adjusting the laser energy ratio of the red light, the green light and the blue light, so that the rainbow effect is inhibited. In practical application, the light with the required wavelength can be selected according to actual needs to carry out beam combination exposure, so that the volume holographic grating for realizing wavelength multiplexing of the light with the corresponding wavelength is obtained.

In some embodiments, the beam combiner 14 may be an X-prism formed by four right-angle prisms bonded together, and the first dichroic film and the second dichroic film are orthogonal to each other on the diagonal surfaces of the X-prism, wherein the first dichroic film is a dichroic film that reflects red light, transmits green light, and blue light, and the second dichroic film is a dichroic film that reflects blue light, transmits red light, and green light. The combiner 14 may also be other suitable spectrum combining devices, and is not limited herein.

In some embodiments, with continued reference to fig. 2, the manufacturing apparatus may further include a polarization splitting prism 80. The light incident side of the polarization beam splitter prism 80 is disposed at the output end of the beam combiner 14, and the light incident side of the light splitting unit 20 is disposed at the light exit side of the polarization beam splitter prism 80. The polarization beam splitter prism 80 is used for emitting the light emitted from the laser light source 10 in a first polarization state (e.g., S polarization state). Specifically, the light incident side and the light exiting side of the polarization beam splitter prism 80 are disposed adjacent to each other, and when the light of the laser light source 10 enters through the light incident side of the polarization beam splitter prism 80, the light in the S-polarization state exits through the light exiting side of the polarization beam splitter prism 80, and the light in the P-polarization state is transmitted through the polarization beam splitter prism 80. The light used for the subsequent exposure is only light of the S polarization state, which can filter light of the P polarization state.

In some embodiments, the manufacturing apparatus further includes a beam expanding and collimating unit, which is disposed between the output end of the beam combiner 14 and the light incident side of the light splitting unit 20. Specifically, referring to fig. 2, the beam expanding and collimating unit includes a spatial filter 15 and a fourier collimator lens 16, and the spatial filter 15 and the fourier collimator lens 16 are sequentially disposed between the light exit side of the polarization beam splitter prism 80 and the light entrance side of the beam splitting unit 20. Like this, the light after closing firstly diverges the back through spatial filter 15 after passing through polarization beam splitter prism 80, and the light after the rethread collimating lens 16 is to the light after diverging carries out the collimation, guarantees the collimation nature of the light beam after the divergence, can obtain the major diameter, parallel light beam finally.

In some embodiments, the manufacturing apparatus further comprises at least one optical stop disposed between the first reflecting unit 31 and the volume holographic film 50, and/or between the second reflecting unit 32 and the volume holographic film 50. Specifically, referring to fig. 2, the manufacturing apparatus may further include a first diaphragm 71 and a second diaphragm 72, the first diaphragm 71 is disposed between the first reflection unit 31 and the first gradual attenuation sheet 61, the second diaphragm 72 is disposed between the second reflection unit 32 and the second gradual attenuation sheet 62, and the sizes of the first light beam L1 and the second light beam L2 may be set by setting the apertures of the first diaphragm 71 and the second diaphragm 72.

In a second aspect, an embodiment of the present invention further provides another apparatus for manufacturing a volume holographic grating, referring to fig. 3, the apparatus includes: the holographic optical system comprises a laser light source 10, a light splitting unit 20, a first reflecting unit 31, a second reflecting unit 32, a first prism 42, a second prism 41, a volume holographic film 50 and at least one piece of gradual attenuation sheet.

The light-incident side of the light-splitting unit 20 is disposed at the light-exiting side of the laser light source 10, and the light-splitting unit 20 is configured to split the light of the laser light source 10 into a first light beam L1 exiting from the first light-exiting side of the light-splitting unit 20 and a second light beam L2 exiting from the second light-exiting side of the light-splitting unit 20. The first reflection unit 31 is disposed on a first light emitting side of the light splitting unit 20, the first side of the second prism 41 is disposed on the light emitting side of the first reflection unit 31, the first side of the volume hologram film 50 is disposed on a second side of the second prism 41, the first reflection unit 31 is configured to emit the first light beam L1 to the first side of the second prism 41, and the second prism 41 is configured to receive the first light beam L1 through the first side of the second prism 41 and emit the first light beam L1 to the volume hologram film 50 through the second side of the second prism 41. The second reflection unit 32 is disposed on the second light emitting side of the light splitting unit 20, the first side of the first prism 42 is disposed on the light emitting side of the second reflection unit 32, the second side of the volume hologram film 50 is disposed on the second side of the first prism 42, the second reflection unit 32 is configured to emit the second light beam L2 to the first side of the first prism 42, and the first prism 42 is configured to receive the second light beam L2 through the first side of the first prism 42 and emit the second light beam L2 to the volume hologram film 50 through the second side of the first prism 42. The gradual attenuation sheet is arranged in the optical path of the first light beam L1 and is used for modulating the transmissivity of the first light beam L1, and/or is arranged in the optical path of the second light beam L2 and is used for modulating the transmissivity of the second light beam L2. The volume hologram film 50 is configured to be exposed by interference of the first beam L1 and the second beam L2 to form a volume hologram grating.

Specifically, the structure of the volume hologram film 50 is the same as that described in the first embodiment of the present invention, and will not be described herein again. The first side of the volume hologram film 50 is attached to the second side of the first prism 42 by the refractive index matching fluid, and the second side of the volume hologram film 50 is also attached to the second side of the second prism 41 by the refractive index matching fluid.

Illustratively, continuing to refer to fig. 3, the at least one graduated attenuation piece includes a first graduated attenuation piece 61 and a second graduated attenuation piece 62, the first graduated attenuation piece 61 is disposed between the first reflection unit 31 and the first side of the second prism 41, and the second graduated attenuation piece 62 is disposed between the second reflection unit 32 and the first side of the first prism 42. The setting of the attenuation ratio of the gradual attenuation sheet and the advantages of the manufacturing device provided by the gradual attenuation sheet are the same as those of the embodiment of the first aspect of the present invention, and are not described herein again.

In the manufacturing apparatus, first, the light beam of the laser light source 10 passes through the light splitting unit 20 and is split into a first light beam L1 and a second light beam L2; then, the first light beam L1 passes through the first reflection unit 31, the first gradual attenuation sheet 61 and the second prism 41 and then exits to the first side of the volume hologram film 50, and the second light beam L2 passes through the second reflection unit 32, the second gradual attenuation sheet 62 and the first prism 42 and then exits to the second side of the volume hologram film 50; finally, the first light beam L1 and the second light beam L2 interfere on the volume hologram film 50, forming a volume hologram grating. In practical applications, the number and the positions of the gradual attenuation pieces and the specific arrangement of the alternative ways of the gradual attenuation pieces are the same as those described in the embodiment of the first aspect of the present invention, and are not described herein again.

Firstly, the device exposes by using the volume holographic film 50, compared with the holographic plate, the volume holographic film 50 has stronger flexibility and extremely light and thin thickness, so that the volume holographic grating manufacturing process is simpler and more flexible. Secondly, by setting the attenuation proportion of the first gradual attenuation sheet 61 and/or the second gradual attenuation sheet 62 in different areas of the attenuation sheets, the light transmittance of the first light beam L1 and/or the second light beam L2 can be changed, and the diffraction efficiency is controlled by controlling the exposure, so that a grating structure in which the diffraction efficiency in different areas of the volume holographic film 50 is changed regularly is manufactured on the volume holographic film 50. In addition, the manufacturing apparatus is simple in manufacturing optical path and high in yield. Meanwhile, the manufacturing device enables two beams of light to interfere on the volume holographic film through the two prisms, the manufactured volume holographic grating can be used as a turning grating in the volume holographic optical waveguide, the manufactured grating is cut subsequently and is arranged on a transparent substrate (such as a glass substrate, a resin substrate and the like) in a fitting mode, and the two-dimensional extended pupil volume holographic optical waveguide can be manufactured.

Specifically, in some embodiments, referring to fig. 4, the first prism 42 and the second prism 41 are right-angled triangular prisms, the second side of the volume hologram film 50 is attached to the second side of the first prism 42 by the refractive index matching fluid, the first side of the volume hologram film 50 is attached to the second side of the second prism 41, by setting the positions of the reflection units, the front view of the exposure angle at the volume hologram film 50 is finally as shown in (a) of FIG. 5, a left view of an exposure angle at the volume hologram film 50 is shown in fig. 5 (b), and thus, by the cooperative arrangement of the respective prisms and the reflection unit, it is possible to change the incident angle of the first light beam L1 to the volume hologram film 50 and to change the incident angle of the second light beam L2 to the volume hologram film 50, thus, interference fringes of different patterns are produced on the volume holographic film 50, and volume holographic gratings of different patterns can be obtained after final exposure.

In the manufacturing process, various volume holographic gratings can be manufactured by changing exposure parameters, wherein the exposure parameters comprise the number of wavelengths of exposure light and exposure angles. The exposure angle includes an incident angle at which the first light beam L1 is incident to the first side of the volume hologram film 50 and an incident angle at which the second light beam L2 is incident to the second side of the volume hologram film 50, and it is understood that the exposure angle may be considered to be different as long as there is a difference in the incident angle of a certain light beam. It should be understood that the process and the adaptation of the manufacturing apparatus for manufacturing the wavelength-multiplexed and/or angle-multiplexed holographic grating are the same as those described in the embodiment of the first aspect of the present invention, and therefore, the detailed description thereof is omitted here.

In some embodiments, the light splitting unit 20 includes a light splitter, an incident side of the light splitter is disposed on an emergent side of the laser light source 10, an incident side of the first reflecting unit 31 is disposed on a transmission side of the light splitter, and an incident side of the second reflecting unit 32 is disposed on a reflection side of the light splitter. The specific arrangement of the beam splitter is the same as that described in the embodiment of the first aspect of the present invention, and will not be described herein again.

In some of the embodiments, the first reflecting unit 31 includes a first mirror; the first reflecting mirror is disposed on the first light outgoing side of the light splitting unit 20, and the first side of the second prism 41 is disposed in the reflecting direction of the first reflecting mirror. The first mirror is used to reflect the first light beam to a first side of the second prism 41. In practical applications, the number of the reflecting mirrors included in the first reflecting unit 31 can be set according to actual needs, and is not limited in this embodiment.

In some embodiments, referring to fig. 3, the second reflecting unit 32 includes a second reflecting mirror 321 and a third reflecting mirror 322; the specific arrangement of the second reflector 321 and the third reflector 322 is the same as that described in the first embodiment of the present invention, and will not be described herein.

In some embodiments, referring to fig. 6, the first reflector is disposed on the first slide rail rotating table. The first slide rail rotating platform can drive the first reflector to translate and rotate. Specifically, this first slide rail revolving stage can drive first speculum at slide rail revolving stage place plane, move along the direction that is on a parallel with the first side of volume holographic membrane 50, in addition, this first slide rail revolving stage can drive first speculum and rotate around the center of first speculum, drive first speculum through first slide rail revolving stage and carry out translation and rotation, can change the incident angle of first light beam L1 at the first side of volume holographic membrane 50, thereby can let volume holographic membrane 50 exposed with different incident angles by first light beam L1.

In some embodiments, referring to fig. 6, the third reflector 322 is disposed on the second track rotation stage. The second slide rotation stage can drive the third reflector 322 to translate and rotate. The specific process and function of the second track rotation stage driving the third reflector 322 to translate and rotate is the same as that described in the embodiment of the first aspect of the present invention, and will not be described herein again.

In some embodiments, referring to fig. 6, the laser light source 10 may include a red laser 11, a blue laser 12, a green laser 13, and a beam combiner 14; further arrangements of the red laser 11, the blue laser 12, the green laser 13 and the beam combiner 14 are the same as those described in the first embodiment of the present invention, and will not be described herein again.

In some embodiments, with continued reference to fig. 6, the manufacturing apparatus may further include a polarization splitting prism 80. The specific arrangement and function of the polarization splitting prism 80 are the same as those of the first embodiment of the present invention, and are not described herein again.

In some embodiments, the manufacturing apparatus further includes a beam expanding and collimating unit, which is disposed between the output end of the beam combiner 14 and the light incident side of the light splitting unit 20. Specifically, referring to fig. 6, the beam expanding and collimating unit includes a spatial filter 15 and a fourier collimator lens 16; the specific arrangement and function of the spatial filter 15 and the fourier collimator lens 16 are the same as those of the first embodiment of the present invention, and will not be described herein again.

In some embodiments, the manufacturing apparatus further comprises at least one optical stop disposed between the first reflecting unit 31 and the volume holographic film 50, and/or disposed between the second reflecting unit 32 and the volume holographic film 50. Specifically, referring to fig. 6, the manufacturing apparatus further includes a first diaphragm 71 and a second diaphragm 72, and the specific arrangement of the first diaphragm 71 and the second diaphragm 72 is the same as that described in the embodiment of the first aspect of the present invention, and is not described herein again.

In a third aspect, an embodiment of the present invention further provides a method for manufacturing a volume holographic optical waveguide, where the method includes the following steps S110 to S130.

Step S110: obtaining a first integral holographic grating by the manufacturing device according to any one embodiment of the first aspect, and cutting the first integral holographic grating to obtain an incoupling grating and/or an outcoupling grating; and/or obtaining a second volume holographic grating by the manufacturing device according to any embodiment of the second aspect, and cutting the second volume holographic grating to obtain a turning grating.

Step S120: a transparent substrate is provided, and the transparent substrate comprises a first area, a second area and a third area. Illustratively, the transparent substrate may be a glass substrate, a resin substrate, or the like.

Step S130: will one the coupling grating laminating sets up the first region, will one the coupling grating laminating sets up the second region, will one the turning grating laminating sets up the third region, perhaps, will be a plurality of the coupling grating stacks the laminating setting in proper order and is in the first region, will be a plurality of the coupling grating stacks the laminating setting in proper order and is in the second region, will be a plurality of the turning grating stacks the laminating setting in proper order and is in the third region, thereby obtains the volume holographic optical waveguide.

Specifically, in the manufacturing method, first, a first volume holographic grating is obtained by the manufacturing apparatus according to any one of the embodiments of the first aspect, as shown in fig. 7 (a), assuming that the diffraction efficiency of the first volume holographic grating 51 gradually increases along the first direction X. Then, the first volume holographic grating 51 is cut to obtain at least one incoupling grating 511 and at least one outcoupling grating 512, as shown in fig. 7 (b). In order to improve the diffraction efficiency of the volume hologram optical waveguide, an incoupling grating 511 is usually selected at a position in the first volume hologram grating 51 where the diffraction efficiency is larger, as shown in fig. 7 (a), and the grating structure on the right side of the first volume hologram grating 51 is usually selected and cut to obtain the incoupling grating 511.

Next, the second volume hologram grating 52 is obtained by the manufacturing apparatus according to any one of the embodiments of the second aspect, and as shown in fig. 8 (a), the diffraction efficiency of the second volume hologram grating 52 is also assumed to gradually increase along the first direction X. Then, the second volume holographic grating 52 is cut to obtain at least one turning grating 521, as shown in (b) of fig. 8.

Finally, a coupling-in grating 511, a coupling-out grating 512 and a turning grating 521 are respectively attached to the corresponding regions on a transparent substrate (e.g., a glass substrate, a resin substrate, etc.) 200, to obtain a volume hologram optical waveguide, as shown in fig. 9.

It should be noted that during the application process, the application is generally performed according to a law that is favorable for the uniform distribution of light throughout the waveguide region. For example, as shown in fig. 9, the diffraction efficiency of the turning grating 521 from the side close to the incoupling grating 511 to the side far from the incoupling grating 511 tends to increase, that is, the diffraction efficiency of the turning grating 521 along the first direction X is ensured to increase, and the diffraction efficiency of the coupling grating 512 from the side close to the turning grating 521 to the side far from the turning grating 521 is ensured to increase, that is, the coupling grating 512 is ensured to increase along the second direction Y, so that the light can be ensured to be uniformly distributed in the whole waveguide region.

In addition, during the attaching process, it is usually ensured that the coupling-in grating 511 couples the image light with image information to the transparent substrate 200, and makes the image light perform total reflection propagation along the first direction X toward the turning grating 521, the turning grating 521 can receive the image light coupled in through the coupling-in grating 511, and makes the image light continue total reflection propagation along the first direction X, and makes the image light perform total reflection propagation along the second direction Y toward the coupling-out grating 512, and the coupling-out grating 512 can finally couple the image light out from the transparent substrate 200. Typically, the first direction X is perpendicular to the second direction Y.

It can be understood that grating periods of the incoupling grating and the outcoupling grating on the same block holographic optical waveguide should be the same, therefore, in general, when manufacturing, the same first integral holographic grating is often used to cut to obtain the incoupling grating and the outcoupling grating, in practical application, the first integral holographic gratings with the same exposure parameters can also be obtained by exposure respectively, and then the first integral holographic gratings and the outcoupling grating can be obtained by cutting respectively.

The volume holographic optical waveguide manufactured by the manufacturing method is simple in manufacturing mode, large-scale mass production can be realized, the production efficiency of the volume holographic optical waveguide can be improved, and the finally manufactured volume holographic optical waveguide is applied to near-eye display equipment and can realize a large field angle and a large eye movement range.

Optionally, in the process of manufacturing the first integral holographic grating, a piece of volume holographic film is simultaneously exposed at a group of exposure angles after the light beams with the N different wavelengths are combined, so as to manufacture the first integral holographic grating with the multiplexed wavelengths; and then, cutting the first integral holographic grating to obtain a wavelength multiplexing coupling-in grating and a wavelength multiplexing coupling-out grating. In the process of manufacturing the second volume holographic grating, the N light beams used in the process of manufacturing the first volume holographic grating are adopted for manufacturing, namely the N light beams with different wavelengths are combined and simultaneously exposed to a volume holographic film at a group of exposure angles to manufacture the second volume holographic grating with the multiplexed wavelength; and then, cutting the second volume holographic grating to obtain the wavelength-multiplexed turning grating. Finally, a wavelength multiplexing coupling-in grating, a wavelength multiplexing coupling-out grating and a wavelength multiplexing turning grating are correspondingly attached to corresponding areas on the transparent substrate, so that the volume holographic optical waveguide for realizing wavelength multiplexing on N light rays with different wavelengths can be manufactured. Wherein N is an integer greater than or equal to 2.

Optionally, in the process of manufacturing the first integral holographic grating, when a block of holographic film is exposed for M times at M groups of different exposure angles by using light with the same wavelength, the first integral holographic grating with multiplexed angles is manufactured; and then, cutting the first integral holographic grating to obtain an angle multiplexing coupling-in grating and an angle multiplexing coupling-out grating. In the process of manufacturing the second volume holographic grating, the light with the wavelength used for manufacturing the first volume holographic grating is adopted for manufacturing, namely, the light with the wavelength is subjected to exposure for M times on a volume holographic film at M groups of different exposure angles to manufacture the angle-multiplexed second volume holographic grating; then, the second volume holographic grating is cut to obtain the angle multiplexing turning grating. Finally, an angle multiplexing coupling-in grating, an angle multiplexing coupling-out grating and an angle multiplexing turning grating are correspondingly attached to corresponding areas on the transparent substrate, and the angle multiplexing volume holographic optical waveguide can be manufactured. Wherein M is an integer greater than or equal to 2.

Optionally, in the process of manufacturing the first volume holographic grating, a light beam formed by combining N light beams with different wavelengths is used to expose a volume holographic film for M times at M groups of different exposure angles, so as to manufacture a first volume holographic grating with wavelength multiplexing and angle multiplexing; and then, cutting the first integral holographic grating to obtain a wavelength multiplexing and angle multiplexing coupling-in grating and a wavelength multiplexing and angle multiplexing coupling-out grating. In the process of manufacturing the second volume holographic grating, exposing a volume holographic film for M times by adopting the light beam formed by combining the N light beams with different wavelengths at M groups of different exposure angles to prepare the second volume holographic grating with wavelength multiplexing and angle multiplexing; then, after cutting, the turning grating for wavelength multiplexing and angle multiplexing is obtained. Finally, an incoupling grating for wavelength multiplexing and angle multiplexing, an outcoupling grating for wavelength multiplexing and angle multiplexing, and a turning grating for wavelength multiplexing and angle multiplexing are attached to the corresponding areas of the transparent substrate, so that the volume holographic optical waveguide for wavelength multiplexing and angle multiplexing can be manufactured.

Specifically, in the process of manufacturing the first integral holographic grating, the light beams after combining red light, blue light and green light can be adopted to expose the volume holographic film at M groups of different exposure angles, so as to obtain the first integral holographic grating with wavelength multiplexing and angle multiplexing; then, the first integral holographic grating is cut, and a wavelength multiplexing and angle multiplexing coupling-in grating and a wavelength multiplexing and angle multiplexing coupling-out grating can be obtained. Similarly, in the process of manufacturing the second volume holographic grating, the volume holographic film is exposed by combining the red light, the blue light and the green light at M groups of different exposure angles to obtain the second volume holographic grating with wavelength multiplexing and angle multiplexing; then, the second volume holographic grating is cut, and the wavelength multiplexing and angle multiplexing turning grating can be obtained. Finally, an incoupling grating for wavelength multiplexing and angle multiplexing, an outcoupling grating for wavelength multiplexing and angle multiplexing, and a turning grating for wavelength multiplexing and angle multiplexing are attached to the corresponding areas of the transparent substrate, so that the volume holographic optical waveguide for wavelength multiplexing and angle multiplexing can be manufactured.

Then, when the light of red, green and blue wavelengths is incident to the wavelength-multiplexed and angle-multiplexed volume holographic optical waveguide, the volume holographic optical waveguide can simultaneously couple in, turn and couple out the red, green and blue light, thereby realizing full-color display; in addition, when the light of the red light, the green light and the blue light is incident at a large angle, the volume holographic optical waveguide has an angle multiplexing function, so that the volume holographic optical waveguide can still have high diffraction efficiency on the light, and large-field display is realized.

In order to ensure the diffraction efficiency, optionally, when the volume holographic optical waveguide with wavelength multiplexing and angle multiplexing is manufactured, in the process of manufacturing the first volume holographic grating, the light beams after the light beams with N different wavelengths are combined are respectively used for exposing the M volume holographic film at M groups of different exposure angles, so that the manufactured M volume holographic gratings are all volume holographic gratings with wavelength multiplexing and respectively correspond to M groups of different exposure angles; then, after cutting the M first integral holographic gratings, obtaining M wavelength multiplexing coupling-in gratings and M wavelength multiplexing coupling-out gratings corresponding to M groups of different exposure angles; then, in the process of manufacturing a second volume holographic grating, after the N light beams with different wavelengths are combined, exposing the M volume holographic films at M groups of different exposure angles respectively, so that the M second volume holographic gratings which are manufactured are all volume holographic gratings with wavelength multiplexing and correspond to the M groups of different exposure angles respectively; then, after M second volume holographic gratings are cut, M wavelength multiplexing turning gratings corresponding to M groups of different exposure angles are obtained; finally, M coupling-in gratings are sequentially laminated and pasted in the first area, M coupling-out gratings are sequentially laminated and pasted in the second area, M turning gratings are sequentially laminated and pasted in the third area, and the volume holographic optical waveguide with wavelength multiplexing and angle multiplexing can also be obtained.

Specifically, in the process of manufacturing the full-color large-view-field-display volume holographic optical waveguide, the light rays of red light, green light and blue light which are combined are used for exposing the M block holographic film at M groups of different exposure angles respectively, so that the manufactured M block first volume holographic gratings are all volume holographic gratings with wavelength multiplexing and correspond to the M groups of different exposure angles respectively; then, after cutting the M first integral holographic gratings, obtaining M wavelength multiplexing coupling-in gratings and M wavelength multiplexing coupling-out gratings corresponding to M groups of different exposure angles; then, in the process of manufacturing the second volume holographic grating, the light rays of which the red light, the green light and the blue light are combined are also adopted to expose the M volume holographic films at M groups of different exposure angles respectively, so that the manufactured M second volume holographic gratings are all volume holographic gratings with wavelength multiplexing and correspond to the M groups of different exposure angles respectively; then, after M second volume holographic gratings are cut, M wavelength multiplexing turning gratings corresponding to M groups of different exposure angles are obtained; and finally, sequentially laminating and sticking the M coupling-in gratings in the first area, sequentially laminating and sticking the M coupling-out gratings in the second area, and sequentially laminating and sticking the M turning gratings in the third area, so that the wavelength multiplexing and angle multiplexing volume holographic optical waveguide can be obtained, and full-color large-view-field display is realized.

In order to ensure diffraction efficiency, optionally, when a volume holographic optical waveguide with wavelength multiplexing and angle multiplexing is manufactured, in the process of manufacturing a first volume holographic grating, N light rays with different wavelengths are respectively adopted to expose N volume holographic films, and when the same volume holographic film is exposed, M groups of different exposure angles are respectively adopted to expose, so that the manufactured N first volume holographic gratings are all volume holographic gratings with angle multiplexing and respectively correspond to the N exposure light rays with different wavelengths; then, after cutting the N first integral holographic gratings, obtaining N angularly multiplexed coupling-in gratings and N angularly multiplexed coupling-out gratings corresponding to N exposure light rays with different wavelengths; then, in the process of manufacturing the second volume holographic grating, respectively exposing the N volume holographic films by adopting N light rays with different wavelengths, and respectively exposing by adopting M groups of different exposure angles when the same volume holographic film is exposed, so that the manufactured N second volume holographic gratings are angle-multiplexed volume holographic gratings and respectively correspond to the N exposure light rays with different wavelengths; then, after N pieces of second volume holographic gratings are cut, N angle multiplexing turning gratings corresponding to N exposure light rays with different wavelengths are obtained; and finally, sequentially laminating and sticking the N coupling-in gratings in the first area, sequentially laminating and sticking the N coupling-out gratings in the second area, and sequentially laminating and sticking the N turning gratings in the third area, thereby obtaining the angle multiplexing and angle multiplexing volume holographic optical waveguide.

Specifically, in the process of manufacturing the first volume holographic grating, the 3 block holographic films are respectively exposed by adopting red light, blue light and green light, and when the same block holographic film is exposed, M groups of different exposure angles are respectively adopted for exposure, so that the 3 manufactured first volume holographic gratings are angle-multiplexed volume holographic gratings and respectively correspond to 3 exposure light rays with different wavelengths; then, cutting the 3 first holographic gratings to obtain 3 angle-multiplexed coupled-in gratings and 3 angle-multiplexed coupled-out gratings which respectively correspond to the red light, the blue light and the green light; then, in the process of manufacturing the second volume holographic grating, respectively exposing the 3 volume holographic films by adopting red light, blue light and green light, and respectively exposing by adopting M groups of different exposure angles when the same volume holographic film is exposed, so that the 3 manufactured second volume holographic gratings are angle-multiplexed volume holographic gratings and respectively correspond to 3 exposure light rays with different wavelengths; then, 3 pieces of second volume holographic gratings are cut to obtain 3 angle multiplexing turning gratings respectively corresponding to red light, blue light and green light; finally, 3 coupling gratings are sequentially stacked and pasted in the first area, 3 coupling gratings are sequentially stacked and pasted in the second area, and 3 turning gratings are sequentially stacked and pasted in the third area, as shown in fig. 10, the angle multiplexing and angle multiplexing volume holographic optical waveguide can be obtained, and full-color large-view-field display is realized.

In a fourth aspect, embodiments of the present invention further provide a volume holographic optical waveguide, which is manufactured by the manufacturing method of the third aspect. The volume holographic optical waveguide is simple in manufacturing mode, capable of realizing large-scale mass production, high in production efficiency, and capable of realizing a large field angle and a large eye movement range when being applied to near-eye display equipment.

In some of these embodiments, the volume holographic optical waveguide is an angle-multiplexed and/or wavelength-multiplexed volume holographic optical waveguide.

In a fifth aspect, embodiments of the present invention also provide a near-eye display device comprising a volume holographic optical waveguide as described in the fourth aspect. The volume holographic optical waveguide manufactured by the manufacturing device has high production efficiency, is applied to near-eye display equipment, and can realize a large field angle and a large eye movement range.

The embodiment of the invention provides a volume grating manufacturing device, a volume holographic optical waveguide, a manufacturing method thereof and near-to-eye display equipment, wherein the manufacturing device comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a volume holographic film and at least one gradual attenuation sheet, or the manufacturing device comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a second prism, a volume holographic film and at least one gradual attenuation sheet; the manufacturing device is simple and high in yield, and meanwhile, the exposed volume holographic film is cut and attached to the corresponding position of the waveguide substrate, so that the volume holographic optical waveguide can be manufactured.

It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for producing a volume holographic grating, the device comprising: the holographic volume holographic film comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a volume holographic film and at least one gradual change attenuation sheet;

the light-emitting side of the laser light source is provided with a light-emitting side of the light-splitting unit, and the light-splitting unit is used for splitting light of the laser light source into a first light beam emitted from a first light-emitting side of the light-splitting unit and a second light beam emitted from a second light-emitting side of the light-splitting unit;

the first reflection unit is arranged on the first light-emitting side, the first side of the volume holographic film is arranged on the light-emitting side of the first reflection unit, and the first reflection unit is used for emitting the first light beam to the volume holographic film;

the second reflection unit is arranged on the second light-emitting side, the first side of the first prism is arranged on the light-emitting side of the second reflection unit, the second side of the volume holographic film is arranged on the second side of the first prism, the second reflection unit is used for emitting the second light beam to the first side of the first prism, and the first prism is used for receiving the second light beam through the first side of the first prism and emitting the second light beam to the volume holographic film through the second side of the first prism;

the gradual attenuation sheet is arranged in the light path of the first light beam and is used for modulating the transmissivity of the first light beam, and/or is arranged in the light path of the second light beam and is used for modulating the transmissivity of the second light beam;

the volume holographic film is used for being exposed by fringes formed by interference of the first light beam and the second light beam to form the volume holographic grating.

2. The production apparatus according to claim 1, wherein the first reflecting unit includes a first mirror;

the first reflector is arranged on the first light-emitting side, and the first side of the volume holographic film is arranged in the reflection direction of the first reflector.

3. The production device according to claim 2, wherein the second reflecting unit includes a second reflecting mirror and a third reflecting mirror;

the second reflector is arranged on the second light-emitting side, the third reflector is arranged on the reflecting direction of the second reflector, and the first side of the first prism is arranged on the reflecting direction of the third reflector.

4. The manufacturing apparatus according to claim 3, wherein the third reflecting mirror is provided on a slide-rail rotating table.

5. The production device according to claim 3 or 4, wherein the laser light source comprises a beam combiner and at least one laser;

each laser is respectively arranged at each input end of the beam combiner, and the light incident side of the light splitting unit is arranged at the output end of the beam combiner.

6. A device for producing a volume holographic grating, the device comprising: the holographic film holographic laser comprises a laser light source, a light splitting unit, a first reflecting unit, a second reflecting unit, a first prism, a second prism, a volume holographic film and at least one gradual change attenuation sheet;

the first reflection unit is arranged on the first light-emitting side, the first side of the second prism is arranged on the light-emitting side of the first reflection unit, the first side of the volume holographic film is arranged on the second side of the second prism, the first reflection unit is used for emitting the first light beam to the first side of the second prism, and the second prism is used for receiving the first light beam through the first side of the second prism and emitting the first light beam to the volume holographic film through the second side of the second prism;

7. The production apparatus according to claim 6, wherein the first reflecting unit includes a first mirror;

the first reflector is arranged on the first light-emitting side, and the first side of the second prism is arranged in the reflection direction of the first reflector.

8. The production device according to claim 7, wherein the second reflecting unit includes a second reflecting mirror and a third reflecting mirror;

9. The manufacturing apparatus of claim 8, wherein the first mirror is disposed on a first slide-to-turn stage, and/or the third mirror is disposed on a second slide-to-turn stage.

10. The production device according to claim 8 or 9, wherein the laser light source comprises a beam combiner and at least one laser;

11. A method of making a volume holographic optical waveguide, comprising:

obtaining a first integral holographic grating by the manufacturing device of any one of claims 1 to 5, and cutting the first integral holographic grating to obtain an in-coupling grating and/or an out-coupling grating; and/or, obtaining a second volume holographic grating by the manufacturing device of any one of claims 6 to 10, and cutting the second volume holographic grating to obtain a turning grating;

providing a transparent substrate, wherein the transparent substrate comprises a first area, a second area and a third area;

will one the coupling grating laminating sets up the first region, will one the coupling grating laminating sets up the second region, will one the turning grating laminating sets up the third region, perhaps, will be a plurality of the coupling grating stacks the laminating setting in proper order and is in the first region, will be a plurality of the coupling grating stacks the laminating setting in proper order and is in the second region, will be a plurality of the turning grating stacks the laminating setting in proper order and is in the third region, thereby obtains the volume holographic optical waveguide.

12. A volume holographic optical waveguide, produced by the method of claim 11.

13. The volume holographic optical waveguide of claim 12, wherein the volume holographic optical waveguide is an angle-multiplexed and/or wavelength-multiplexed volume holographic optical waveguide.

14. A near-eye display device comprising the volume holographic optical waveguide of claim 12 or 13.