Apparatus for manufacturing holographic optical element and method of manufacturing the same

Abstract

The application relates to a holographic optical element manufacturing device, which comprises a laser light source, a beam expander assembly, a polarizer, a manufacturing jig and a reflecting assembly. The manufacturing jig is used for placing a transparent plate, which comprises a medium layer and a holographic photosensitive film. The reflecting assembly is a first prism, which is attached to the transparent plate through glycerol with a refractive index of 1.52 and comprises a first reflecting surface. Polarized light is converted into reflected light along a second optical axis through the first reflecting surface, the reflected light penetrates the holographic photosensitive film, and the polarized light and the reflected light interfere with each other on the holographic photosensitive film to form a grating. Since the first prism is attached to the transparent plate through glycerol, the reflected light path can be shortened, the influence of vibration on the stability of interference exposure can be reduced, and the manufacturing yield and optical quality of the holographic optical element can be maintained.

Description

Technical Field

[0001] This application relates to the field of optical technology, and in particular to an apparatus and method for manufacturing a holographic optical element. Background Technology

[0002] A holographic optical element is an optical element made using the holographic principle, with various applications such as imaging, beam splitting, beam combining, beam polarization, and optical modulation. Among these, the most well-known imaging application involves using holographic optical elements to generate virtual images that appear to be behind the element, or real images that appear to be in front of the element. This can be applied to head-up display (HUD) systems in autonomous driving. Furthermore, the small size and light weight of holographic optical elements make them suitable for lightweight portable devices, such as augmented reality (AR) systems that overlay virtual images onto real-world scenes for interactive experiences.

[0003] See Figure 1 The conventional holographic optical element manufacturing apparatus 7 includes a laser light source 71, a beam expander 72, a first half-wave plate 73, a polarizing beam splitter 74, a first reflective element 75, a second half-wave plate 76, a second reflective element 77, a manufacturing fixture 78, and a transparent plate 79.

[0004] The laser source 71 is used to emit laser light.

[0005] The beam expander 72 is positioned in front of the laser source 71 along the direction of light propagation and is used to convert the laser into expanded beam light.

[0006] The first half-wave plate 73 is positioned in front of the beam expander 72 along the direction of light propagation and is used to adjust the polarization direction of the expanded light. The polarization beam splitter 74 is positioned in front of the first half-wave plate 73 along the direction of light propagation and is used to split the polarized light into a first beam splitter and a second beam splitter with a preset angle between their optical paths.

[0007] The first reflective element 75 is disposed in front of the polarizing beam splitter 74 along the forward direction of the first beam splitter's optical path, and is used to convert the first beam splitter into the first reflected light.

[0008] The second half-wave plate 76 is positioned in front of the polarizing beam splitter 74 along the forward direction of the second beam splitting optical path, and is used to convert the second beam splitting into second polarized light, making its polarization direction the same as that of the first beam splitting. The second reflecting element 77 is positioned in front of the second half-wave plate 76 along the forward direction of the second polarized light optical path, and is used to convert the second polarized light into second reflected light.

[0009] The manufacturing fixture 78 is positioned in front of the first reflective element 75 along the direction of the light path of the first reflected light.

[0010] A transparent plate 79 is disposed on a manufacturing fixture 78. The transparent plate 79 includes a first surface 791 near the first reflective element 75, a second surface 792 away from the first reflective element 75, a dielectric layer 793 having the first surface 791, and a holographic photosensitive film 794 having the second surface 792. First reflected light passes through the transparent plate 79 from the first surface 791, and second reflected light passes through the transparent plate 79 from the second surface 792. The first and second reflected light interfere with each other and form a grating in the holographic photosensitive film 794, thereby producing a holographic optical element.

[0011] However, during the manufacturing process, vibrations of individual components and assemblies within the device can cause defects such as decreased contrast of interference fringes, decreased brightness, decreased refractive index change, and decreased diffraction efficiency. These vibrations can originate from air conditioning, movement or conversation of personnel, vibrations from other equipment, or external factors such as transportation, construction, and natural environmental events like earthquakes and wind. While these defects can be mitigated by increasing the distance between components and assemblies, the required spacing between these components is limited by their size and must be sufficient to create a holographic optical element.

[0012] See Figure 2 This is another conventional holographic optical element manufacturing apparatus 7, which also includes a laser light source 71, a beam expander 72, a first half-wave plate 73, a polarizing beam splitter 74, a first reflective element 75, a second half-wave plate 76, a second reflective element 77, a manufacturing fixture 78, and a transparent plate 79. The difference is that the second reflected light, like the first reflected light, passes through the transparent plate 79 from the first surface 791, but it still cannot improve the deficiencies caused by vibration, such as decreased contrast of interference fringes, decreased brightness, decreased refractive index change, and decreased diffraction efficiency. Summary of the Invention

[0013] Based on this, the main objective of this application is to provide a manufacturing apparatus and method for a holographic optical element that can reduce the effects of vibration.

[0014] According to a first aspect of this application, an apparatus for manufacturing a holographic optical element is provided, comprising:

[0015] A laser source, used to emit laser light along the first optical axis;

[0016] A beam expander assembly is positioned in front of the laser source along the forward direction of the first optical axis to convert the laser beam into expanded beam light.

[0017] A polarizer is positioned in front of the beam expander assembly along the forward direction of the first optical axis to convert the expanded beam light into polarized light.

[0018] A manufacturing fixture is positioned in front of the polarizer along the forward direction of the first optical axis; and

[0019] A reflective component is disposed in front of the manufacturing fixture along the forward direction of the first optical axis. It is used to convert polarized light into reflected light along the second optical axis. The reflected light penetrates the manufacturing fixture, and the polarized light and the reflected light interfere with each other in the manufacturing fixture.

[0020] In some embodiments, the manufacturing fixture includes a first surface close to the polarizer and a second surface away from the polarizer, and the reflective component includes a first reflective surface that is tilted away from the polarizer such that a first angle is formed between the first reflective surface and the second surface, and polarized light is converted into reflected light along the second optical axis by the first reflective surface.

[0021] In some embodiments, the reflective component is a first prism, which is disposed adjacent to a manufacturing fixture, and the first reflective surface is the reflective surface of the first prism.

[0022] In some embodiments, the reflective component is a first reflector, and the first reflective surface is the reflective surface of the first reflector.

[0023] In some embodiments, the first reflector is disposed adjacent to the manufacturing fixture, and the distance between the first reflector and the manufacturing fixture is a first gap, which is 1 mm to 100 mm.

[0024] In some embodiments, the manufacturing fixture includes a first surface close to the polarizer and a second surface away from the polarizer. The reflective assembly includes a first reflective surface and a second reflective surface. The first reflective surface is tilted away from the polarizer such that a first angle is formed between the first reflective surface and the second surface. The second reflective surface is tilted away from the polarizer such that a second angle is formed between the second reflective surface and the second surface. Polarized light is converted into reflected light along a second optical axis by the first reflective surface and the second reflective surface.

[0025] In some embodiments, the reflective assembly further includes a second prism disposed adjacent to a manufacturing fixture, wherein the first reflective surface and the second reflective surface are two reflective surfaces on the second prism.

[0026] In some embodiments, the reflective component further includes a first reflector and a second reflector, wherein the first reflective surface is the reflective surface of the first reflector and the second reflective surface is the reflective surface of the second reflector.

[0027] In some embodiments, the first reflector and the second reflector are disposed adjacent to the manufacturing fixture, and the distances between the first reflector and the second reflector and the manufacturing fixture are a first gap and a second gap, respectively, which are 1 mm to 100 mm.

[0028] According to a second aspect of this application, a method for manufacturing a holographic optical element is provided, which uses the aforementioned holographic optical element manufacturing apparatus to fabricate the holographic optical element, and the method includes the following steps:

[0029] A manufacturing fixture is used to place a transparent plate, which includes a dielectric layer and a holographic photosensitive film. The dielectric layer is close to the polarizer and the holographic photosensitive film is far from the polarizer, or the holographic photosensitive film is close to the polarizer and the dielectric layer is far from the polarizer.

[0030] Polarized light penetrates the transparent plate;

[0031] Reflected light penetrates the holographic photosensitive film;

[0032] Polarized light and reflected light interfere with each other to form a grating on the holographic photosensitive film, thereby forming a holographic optical element.

[0033] According to a third aspect of this application, a holographic optical element is provided, which is manufactured by the aforementioned method for manufacturing holographic optical elements.

[0034] In some embodiments, the refractive index of the holographic photosensitive film is 1 to 3.5, and the refractive index variation of the holographic optical element is 0.01 to 0.3.

[0035] In summary, the technical advantage of this application lies in the fact that the distance between the reflective component and the manufacturing fixture can be quite close. When the various components and parts in the device vibrate individually, it can improve deficiencies such as decreased contrast, decreased refractive index change, decreased brightness, and decreased diffraction efficiency, thus maintaining the yield of holographic optical elements and preserving better refractive index change, brightness, and diffraction efficiency. In other words, even with vibrations from air conditioning, personnel movement or conversation, and other equipment, or vibrations from external vehicles, construction projects, and natural environmental factors such as earthquakes and wind, high-quality holographic optical elements can still be manufactured. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a manufacturing apparatus for a holographic optical element in related technologies.

[0037] Figure 2 This is a schematic diagram of a manufacturing apparatus for another holographic optical element in related technologies.

[0038] Figure 3 This is a schematic diagram of a first embodiment of a manufacturing apparatus for a holographic optical element according to this application.

[0039] Figure 4 This is a partially enlarged schematic diagram of the first embodiment of this application.

[0040] Figure 5 This is a schematic diagram of experimental data from the first embodiment of this application.

[0041] Figure 6 This is a schematic diagram of a second embodiment of a manufacturing apparatus for a holographic optical element according to this application.

[0042] Figure 7 This is a schematic diagram of a third embodiment of a holographic optical element manufacturing apparatus according to this application.

[0043] Figure 8 This is a schematic diagram of a fourth embodiment of a manufacturing apparatus for a holographic optical element according to this application.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1: Laser source

[0046] 2: Beam expander assembly

[0047] 21: Focusing Lens

[0048] 22: Pinhole Components

[0049] 3: Polarizing filter

[0050] 4: Manufacturing jig

[0051] 41: First Page

[0052] 42: Second page

[0053] 5: Transparent panel

[0054] 51: Dielectric layer

[0055] 52: Holographic film

[0056] 6: Reflection Components

[0057] 60: First Prism

[0058] 61: Second Prism

[0059] 62: First reflecting surface

[0060] 63: Second reflecting surface

[0061] 64: First reflecting mirror

[0062] 65: Second reflecting mirror

[0063] L1: First optical axis

[0064] L2: Second optical axis

[0065] θ1: First angle

[0066] θ2: Second angle

[0067] g1: First spacing

[0068] g2: Second spacing

[0069] 7: Manufacturing equipment

[0070] 71: Laser source

[0071] 72: Beam Expander Assembly

[0072] 73: First Half-Wave Plate

[0073] 74: Polarization beam splitter

[0074] 75: First reflecting element

[0075] 76: Second Half-Wave Plate

[0076] 77: Second reflective element

[0077] 78: Manufacturing jig

[0078] 79: Transparent Board

[0079] 791: First Page

[0080] 792: Second Page

[0081] 793: Dielectric layer

[0082] 794: Holographic Photosensitive Film Detailed Implementation

[0083] To make the technical problems solved by this application, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of this application will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not all of them.

[0084] In this application, unless otherwise expressly specified and limited, the terms "above," "below," "in front of," or "behind" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "before," "in front of," "in front of," and "in front of" the first feature includes the first feature directly in front of and diagonally in front of the second feature. "After," "behind," "rear," and "behind" the first feature includes the first feature directly behind and diagonally behind the second feature. The use of the quantifiers "a" or "an" for elements and components throughout this application is for convenience only and to provide the general meaning of the scope of this invention; it should be interpreted as including one or at least one, and a single concept also includes plural cases, unless it clearly indicates otherwise.

[0085] In the description of this embodiment, the terms "upper," "lower," "front," or "rear," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used only for descriptive distinction and have no special meaning.

[0086] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0087] See Figure 3 This application discloses a manufacturing apparatus for a holographic optical element. In the first embodiment of this application, the manufacturing apparatus for a holographic optical element includes a laser light source 1, a beam expander 2, a polarizer 3, a manufacturing fixture 4, and a reflection component 6.

[0088] Laser source 1 is used to emit laser light along the first optical axis L1.

[0089] The beam expander 2 is positioned in front of the laser source 1 along the forward direction of the first optical axis L1, and is used to convert the laser into beam expanded light.

[0090] The polarizer 3 is positioned in front of the beam expander 2 along the forward direction of the first optical axis L1, and is used to convert the expanded beam light into polarized light.

[0091] The manufacturing fixture 4 is positioned in front of the polarizer 3 along the forward direction of the first optical axis L1.

[0092] The reflective component 6 is disposed in front of the manufacturing fixture 4 along the forward direction of the first optical axis L1, and is used to convert polarized light into reflected light along the second optical axis L2. The reflected light penetrates the manufacturing fixture 4, and the polarized light and the reflected light interfere with each other in the manufacturing fixture 4.

[0093] Because the distance between the reflective component 6 and the manufacturing fixture 4 can be quite close, when the various components and parts in the device vibrate individually, it can improve deficiencies such as decreased contrast, decreased refractive index change, decreased brightness, and decreased diffraction efficiency. Therefore, the holographic optical element manufacturing apparatus can maintain the yield rate of holographic optical element manufacturing and preserve the refractive index change, brightness, diffraction efficiency, etc. In other words, even with vibrations from air conditioning, personnel movement or conversation, and other equipment, or vibrations from external vehicles, construction projects, and natural environments such as earthquakes and wind, high-quality holographic optical elements can still be manufactured.

[0094] In more detail, in the first embodiment of this application, the wavelength of the laser is 532nm.

[0095] The beam expander assembly 2 includes a set of focusing lenses 21 and a pinhole element 22 disposed at the focal point of the focusing lenses 21.

[0096] The manufacturing fixture 4 is used to place the transparent plate 5. The manufacturing fixture 4 includes a first surface 41 close to the polarizer 3 and a second surface 42 away from the polarizer 3.

[0097] Polarized light passes through a transparent plate 5, which includes a dielectric layer 51 and a holographic photosensitive film 52. The refractive index of the holographic photosensitive film 52 is between 1 and 3.5. In the first embodiment of this application, the side of the dielectric layer 51 facing the polarizer 3 is coplanar with the first surface 41, and the side of the holographic photosensitive film 52 away from the polarizer 3 is coplanar with the second surface 42. The dielectric layer 51 is made of glass with a refractive index of 1.51. The refractive index of the holographic photosensitive film 52 is 1.51. It is worth mentioning that, in addition to having the same refractive index of 1.51, the dielectric layer 51, the holographic photosensitive film 52, and the reflective component 6 can also be made of materials with different refractive indices, with a difference in refractive index of less than 0.8 between them.

[0098] It is worth mentioning that the dielectric layer 51 and the holographic photosensitive film 52 can also be interchanged. The side of the holographic photosensitive film 52 facing the polarizer 3 is coplanar with the first surface 41, and the side of the dielectric layer 51 away from the polarizer 3 is coplanar with the second surface 42. (Not shown in the figure)

[0099] See also Figure 4 The reflective component 6 includes a first reflective surface 62, which is tilted away from the polarizer 3, such that a first angle θ1 is formed between the first reflective surface 62 and the second surface 42, and the polarized light is converted into reflected light along the second optical axis L2 by the first reflective surface 62.

[0100] In the first embodiment of this application, the reflective component 6 is a first prism 60. The first prism 60 is disposed adjacent to the manufacturing fixture 4. The first reflective surface 62 is the reflective surface of the first prism 60, for example, by depositing a metal film on one side of the first prism 60 to make it the first reflective surface 62. The refractive index of the first prism 60 is 1.51.

[0101] More specifically, the reflective component 6 is disposed facing the second surface 42 and is used to convert polarized light into reflected light along the second optical axis L2. The reflected light penetrates the holographic photosensitive film 52, and the polarized light and reflected light interfere with each other to form a grating in the holographic photosensitive film 52. The holographic photosensitive film 52 is thus manufactured as a holographic optical element. In the first embodiment of this application, the exposure time of the polarized light and reflected light to the holographic photosensitive film 52 is approximately 20 seconds.

[0102] It is worth mentioning that the first prism 60 is attached to the transparent plate 5 by glycerol with a refractive index of 1.52, or by other liquids with a refractive index close to that of the transparent plate 5. After the holographic photosensitive film 52 is manufactured as a holographic optical element, the reflective component 6 can be easily separated from the transparent plate 5.

[0103] The refractive index change of the fabricated holographic optical element The value ranges from 0.01 to 0.3. (See also: [link to relevant documentation]) Figure 5 In the first embodiment of this application, the total absorption of the holographic photosensitive film 52 at different wavelengths of laser light (457nm, 532nm, 633nm) reaches 100mJ / cm². 2 The above refers to the change in refractive index of the holographic optical element. The diffraction efficiency is 0.03 to 0.04. The diffraction efficiency of holographic optical elements is 80% to 100%.

[0104] In summary, the advantage of the first embodiment of the holographic optical element manufacturing apparatus of this application is that the distance between the reflective component 6 and the manufacturing fixture 4 can be quite close. More specifically, in the first embodiment, the reflective component 6 is attached to the transparent plate 5. When each component and assembly in the apparatus vibrates, it can improve defects such as decreased contrast, decreased refractive index change, decreased brightness, and decreased diffraction efficiency, thereby maintaining the yield of the holographic optical element.

[0105] See Figure 6 This is a second embodiment of the manufacturing apparatus for the holographic optical element of this application. The second embodiment is substantially the same as the first embodiment, except that the reflecting component 6 is a first reflecting mirror 64, the first reflecting surface 62 is the reflecting surface on the first reflecting mirror 64, and the polarized light is converted into reflected light along the second optical axis L2 by the first reflecting mirror 64.

[0106] The first reflector 64 is disposed near the manufacturing fixture 4, that is, the first reflector 64 is disposed near the second surface 42 of the transparent plate 5, and the distance between the first reflector 64 and the transparent plate 5 is the first spacing g1.

[0107] In the second embodiment of this application, the first spacing g1 is 1mm to 100mm to avoid the first reflector 64 scratching the holographic photosensitive film 52 of the transparent plate 5.

[0108] See Figure 7 This is a third embodiment of the manufacturing apparatus for the holographic optical element of this application. The third embodiment differs from the first embodiment in that the reflective component 6 further includes a second reflective surface 63, which is tilted away from the polarizer 3, such that a second angle is formed between the second reflective surface 63 and the second surface 42. The polarized light is converted into reflected light along the second optical axis L2 by the first reflecting surface 62 and the second reflecting surface 63. Furthermore, the first reflecting surface 62 of the reflecting assembly 6 is mainly used to adjust the position of the light beam, while the second reflecting surface 63 is mainly used to adjust the incident angle of the reflected light.

[0109] In the third embodiment of this application, the reflective component 6 is a second prism 61, which is disposed adjacent to the manufacturing fixture 4, and the first reflective surface 62 and the second reflective surface 63 are the two reflective surfaces of the second prism 61.

[0110] In the first embodiment (e.g.) Figure 4 The first prism 60 of the present invention is simpler in design than the second prism 61 of the third embodiment of the present application, but the overlap between polarized light and reflected light is smaller, resulting in a smaller effective area of ​​the holographic photosensitive film 52. In contrast, the third embodiment of the present application (such as...) Figure 7 Although the design of the second prism 61 is more complex, the effective area of ​​the holographic photosensitive film 52 is larger, which can reduce manufacturing costs.

[0111] See Figure 8 This is the fourth embodiment of the manufacturing apparatus for the holographic optical element of this application. The fourth embodiment differs from the second embodiment in that the reflective component 6 further includes a second reflector 65, and the second reflective surface 63 is the reflective surface of the second reflector 65.

[0112] Polarized light is converted into reflected light along the second optical axis L2 by the first reflector 64 and the second reflector 65. The first reflector 64 and the second reflector 65 are disposed adjacent to the manufacturing fixture 4, that is, the first reflector 64 and the second reflector 65 are disposed adjacent to the second surface 42 of the transparent plate 5. The distances between the first reflector 64 and the second reflector 65 and the transparent plate 5 are respectively the first spacing g1 and the second spacing g2.

[0113] In the fourth embodiment of this application, the first spacing g1 and the second spacing g2 are 1mm to 100mm respectively, so as to avoid the first reflector 64 and the second reflector 65 scratching the holographic photosensitive film 52 of the transparent plate 5.

[0114] Compared with the second embodiment, the fourth embodiment of this application has a larger effective area of ​​the holographic photosensitive film 52, which can reduce manufacturing costs.

[0115] It is worth mentioning that the first reflector 64 and the second reflector 65 can be installed as a single unit or separately.

[0116] In summary, the technical advantage of this application lies in the fact that the reflective component 6 and the manufacturing fixture 4 can be quite close together, and the distances between the first prism 60, the second prism 61, the first reflector 64, the second reflector 65 and the transparent plate 5 are quite close or even touching. When each component in the device vibrates, it can improve deficiencies such as decreased contrast, decreased refractive index change, decreased brightness, and decreased diffraction efficiency, basically maintaining the yield of the holographic optical element and preserving the refractive index change, brightness, diffraction efficiency, etc. In other words, even with vibrations from air conditioning, personnel movement or conversation, and other equipment, or vibrations from external vehicles, construction projects, and natural environments such as earthquakes and wind, high-quality holographic optical elements can still be manufactured.

[0117] However, the above description is merely an embodiment of this application and should not be construed as limiting the scope of this application. Any simple equivalent changes and modifications made in accordance with the scope of protection of this application and the specification shall fall within the scope of the rights of this application.

Claims

1. An apparatus for manufacturing holographic optical elements, characterized in that, include: A laser source, used to emit laser light along the first optical axis; A beam expander assembly is disposed in front of the laser source along the forward direction of the first optical axis, and is used to convert the laser into expanded beam light; A polarizer is disposed in front of the beam expander assembly along the forward direction of the first optical axis to convert the expanded beam light into polarized light. A manufacturing fixture is disposed in front of the polarizer along the forward direction of the first optical axis. The manufacturing fixture is used to place a transparent plate, which includes a dielectric layer and a holographic photosensitive film. as well as A reflective component is disposed in front of the manufacturing fixture along the forward direction of the first optical axis; The manufacturing fixture includes a first side close to the polarizer and a second side away from the polarizer; The reflective component is a first prism, which is disposed adjacent to the manufacturing fixture and the transparent plate, and the first prism is attached to the transparent plate by glycerin with a refractive index of 1.

52. The first prism includes a first reflecting surface, which is tilted away from the polarizer, such that a first angle is formed between the first reflecting surface and the second surface. The polarized light is converted into reflected light along the second optical axis by the first reflective surface, the reflected light penetrates the holographic photosensitive film, and the polarized light and the reflected light interfere with each other to form a grating on the holographic photosensitive film.

2. A method for manufacturing a holographic optical element, comprising using the holographic optical element manufacturing apparatus of claim 1 to manufacture the holographic optical element, characterized in that, The method includes the following steps: The manufacturing fixture holds the transparent plate, which includes the dielectric layer and the holographic photosensitive film. The dielectric layer is close to the polarizer, and the holographic photosensitive film is away from the polarizer, or the holographic photosensitive film is close to the polarizer, and the dielectric layer is away from the polarizer. The first prism is attached to the transparent plate using glycerol with a refractive index of 1.52; The polarized light penetrates the transparent plate; The polarized light is converted into reflected light along the second optical axis by the first reflecting surface; The reflected light penetrates the holographic photosensitive film; as well as The polarized light and the reflected light interfere with each other to form a grating on the holographic photosensitive film, thereby forming the holographic optical element.

3. A holographic optical element, characterized in that, The holographic optical element manufactured by the method for manufacturing a holographic optical element as described in claim 2.

4. The holographic optical element as described in claim 3, characterized in that, The refractive index of the holographic photosensitive film is 1 to 3.5, and the refractive index variation of the holographic optical element is 0.01 to 0.3.

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