Holographic optical element exposure device, system and method

Abstract

The embodiment of the invention belongs to the vehicle-mounted head-up display technology, and provides a holographic optical element exposure device, system and method, and the device comprises an exposure module and a feedback module. The exposure module comprises a laser and an exposure light path, and the exposure light path receives the phase sent by the control equipment; laser emitted by a laser is split, and object light and reference light are obtained; the object light comprises first object light and second object light, the reference light comprises first reference light and second reference light, the first object light and the first reference light are used for exposing a photosensitive material, and the second object light and the second reference light are used for generating first interference fringes; and the feedback module obtains a feedback image including the first interference fringes and sends the feedback image to the control device, so that the control device adjusts the phase of the object light until the difference between the first interference fringes and the reference interference fringes is within a preset range, and outputs the target phase of the object light, the photosensitive material is exposed according to the object light of the target phase, and the exposure precision is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to vehicle-mounted head-up display technology, and more specifically, to a holographic optical element exposure device, system, and method. Background Art

[0002] Holographic optical elements are optical components made based on the principles of holography. Due to their lightweight, compact size, and excellent performance, they are widely used in a variety of fields, including imaging and display technology, optical communications, and optical storage. In recent years, with the development of HUDs (Head-Up Displays), holographic optical elements have also been widely used in HUDs.

[0003] Currently, in holographic optical element-based ARHUD (Augmented Reality HUD) systems, HOE (Holographic Optical Elements) films are exposed through interference exposure between reference light and object light. A conventional HOE film exposure method involves using laser light output from a laser light source to capture object light and reference light. These light then interfere with the exposure path of the object light and reference light, exposing the photosensitive material. This process then records the designed object light phase information on the photosensitive material, completing the HOE film processing.

[0004] Since the object light and reference light need to undergo beam reduction and turning, there will be certain deviations and distortions in the propagation angles and phases they carry after beam reduction and turning. In addition, due to various factors such as the uneven distribution of the laser light source output intensity, platform vibration, and air disturbance, the object light phase information recorded on the HOE film after exposure deviates from the designed object light phase information, resulting in low accuracy in HOE film processing. Summary of the Invention

[0005] The embodiments of the present application provide a holographic optical element exposure device, system, and method, which can be used to solve the problem of low precision in HOE film processing in related technologies.

[0006] In a first aspect, an embodiment of the present application provides a holographic optical element exposure device, the holographic optical element exposure device comprising: an exposure module and a feedback module;

[0007] The exposure module includes a laser and an exposure optical path, wherein the laser is used to emit laser light, and the exposure optical path is used to receive a phase sent by a control device; the laser light is split to obtain object light and reference light; the object light has a phase sent by the control device and includes a first object light and a second object light; the reference light includes a first reference light and a second reference light; the first object light and the first reference light are used to interfere with each other to expose a photosensitive material to obtain a holographic optical element; the second object light and the second reference light are used to interfere with each other to generate first interference fringes;

[0008] The feedback module is configured to obtain a feedback image including the first interference fringes, and send the feedback image to a control device, so that the control device adjusts the phase of the object light based on the feedback image, and sends the adjusted phase to the exposure optical path until the difference between the distribution of the first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes is within a preset range, and output a target phase of the object light, so as to expose the photosensitive material according to the object light with the target phase;

[0009] The distribution of the reference interference fringes is calculated by the control device based on the first reference light and the first object light with an initial phase.

[0010] In a second aspect, an embodiment of the present application provides a holographic optical element exposure system, wherein the holographic optical element exposure system includes a control device and the holographic optical element exposure apparatus according to any one of the first aspects.

[0011] In a third aspect, an embodiment of the present application provides a holographic optical element exposure method, which is applied to a control device, comprising:

[0012] receiving a feedback image including first interference fringes sent by a holographic optical element exposure device;

[0013] adjusting the phase of the object light based on the feedback image, and sending the adjusted phase to an exposure optical path in the holographic optical element exposure device until a difference between the distribution of first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes falls within a preset range, outputting a target phase of the object light, and exposing a photosensitive material according to the object light with the target phase;

[0014] The target phase is the phase of the object light that generates the first interference fringes when the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range;

[0015] The distribution of the reference interference fringes is calculated by the control device based on the first reference light and the first object light with an initial phase;

[0016] The object light includes the first object light and the second object light. The first object light and the first reference light are used to interfere with each other to expose the photosensitive material and obtain the holographic optical element. The second object light and the second reference light are used to interfere with each other to generate first interference fringes.

[0017] The present application provides a holographic optical element exposure device, system and method. The holographic optical element exposure device includes an exposure module and a feedback module. The exposure module includes a laser and an exposure light path. The laser emits laser light, and the exposure light path receives the phase sent by the control device. By splitting the laser light, object light and reference light are obtained. The phase of the object light is the phase sent by the control device, including the first object light and the second object light. The reference light includes the first reference light and the second reference light. The first object light and the first reference light are used to expose the photosensitive material to obtain the holographic optical element. The second object light and the second reference light interfere to produce the first interference fringes for feedback. Specifically, the feedback module based on the present application obtains the feedback image including the first interference fringes and sends it to the control device so that the control device adjusts the phase of the object light until the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range, and the phase of the object light at this time is used as the target phase and output. A photosensitive material to be exposed is placed in a holographic optical element exposure device. The holographic optical element exposure device exposes the photosensitive material according to the object light of the target phase. The interference fringes appearing on the photosensitive material are first interference fringes. Since the difference between the first interference fringes and the reference interference fringes is small at this time, and since the reference interference fringes are obtained by interference between the object light of the initial phase and the first reference light in the absence of errors, the object light information recorded on the photosensitive material at this time is the required initial phase, thereby eliminating errors caused by various factors and improving the accuracy and efficiency of holographic optical element exposure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the implementation methods in the embodiments of the present application or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technology descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0019] Figure 1 A schematic structural diagram of a HOE membrane provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of the preparation principle of a HOE membrane provided in an embodiment of the present application;

[0021] Figure 3 A schematic diagram of the application principle of an HOE membrane provided in an embodiment of the present application;

[0022] Figure 4 A schematic diagram of the structure of the HOE film interference exposure light path in a related technology;

[0023] Figure 5 Schematic diagram of the structure of a Michelson interferometer;

[0024] Figure 6 A schematic diagram of an application scenario of a head-up display device provided in an embodiment of the present application;

[0025] Figure 7 A schematic diagram of the structure of a holographic optical element exposure device provided in an embodiment of the present application Figure 1 ;

[0026] Figure 8 A schematic structural diagram of an exposure module provided in an embodiment of the present application;

[0027] Figure 9 A schematic diagram of the structure of a feedback module provided in an embodiment of the present application;

[0028] Figure 10 A schematic diagram of an interference fringe spectrum signal corresponding to an optical path difference of 60 microns provided in an embodiment of the present application;

[0029] Figure 11 A schematic diagram of the interference fringe spectrum signal corresponding to an optical path difference of 30 microns provided in an embodiment of the present application;

[0030] Figure 12 A schematic diagram of the interference fringe spectrum signal corresponding to an optical path difference of 10 microns provided in an embodiment of the present application;

[0031] Figure 13 A schematic diagram of an interference fringe spectrum signal corresponding to an optical path difference of less than 100 nanometers provided in an embodiment of the present application;

[0032] Figure 14 A schematic diagram of the structure of a holographic optical element exposure device provided in an embodiment of the present application Figure 2 ;

[0033] Figure 15 The process of a holographic optical element exposure method provided in the embodiment of the present application Figure 1 ;

[0034] Figure 16 The process of a holographic optical element exposure method provided in the embodiment of the present application Figure 2 ;

[0035] Figure 17 A schematic structural diagram of a holographic optical element exposure system provided in an embodiment of the present application;

[0036] Figure 18 A schematic structural diagram of a control device provided in this application;

[0037] Figure 19 A schematic diagram of a control device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0039] It should be noted that the brief descriptions of terms in this application are only for the purpose of facilitating the understanding of the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and usual meanings.

[0040] In addition, the terms "comprises" and "comprising" and any variations thereof are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to those components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0041] Figure 1 This is a schematic diagram of the structure of a HOE membrane provided in the embodiment of the present application, refer to Figure 1 As shown in the figure, after the reference light is incident on the HOE film after interference exposure, the reproduced light can be obtained. The thickness of the HOE film after interference exposure is d, and its internal structure is a Bragg grating structure with two alternating refractive indices. The area inside the rectangle is the high refractive index region with a refractive index of n1, and the area between the rectangles is the low refractive index region with a refractive index of n0, where n1 = n0 + Δ, where Δ represents the difference between the refractive indices n1 and n0.

[0042] A Bragg grating is a periodic microstructure that forms a diffraction pattern by splitting a light beam into multiple beams and recombining them to form a diffraction pattern, known as Bragg grating diffraction. The diffraction pattern is caused by phase differences in the beams, which are caused by changes in the refractive index as the beams pass through the Bragg grating. This diffraction pattern can be used to implement holographic optical elements, manipulating the intensity distribution of a light beam, such as focusing or diverging it.

[0043] Figure 2 A schematic diagram of the preparation principle of a HOE membrane provided in the embodiment of this application, refer to Figure 2As shown, the reference light is a parallel light wave without lens information. The signal light passes through the lens array to obtain the object light, which is a focused spherical wave containing lens information. Based on the interference of the reference light and the object light, interference fringes can be recorded on the photosensitive material, realizing the preparation of HOE film.

[0044] Figure 3 This is a schematic diagram of the application principle of a HOE membrane provided in the embodiment of the present application, refer to Figure 3 As shown, when the reproduced light is incident on the HOE film at the angle and wavelength of the reference light, the HOE film will exhibit its recorded light intensity distribution regulation function, converting the reproduced light incident with parallel light into a reconstructed focused spherical wave.

[0045] Figure 4 This is a schematic diagram of the structure of the HOE film interference exposure light path in a related technology, refer to Figure 4 As shown, the object light phase of the designed HOE film is loaded onto the SLM45 (Spatial Light Modulator) through a computer. Figure 4 The computer is not shown. Laser light is emitted from laser 41, collimated by collimating lens 42, and split by beam splitter 43. One beam passes through lens assembly 44 and SLM 45, where it is phase-corrected and then incident on one side of a three-axis translation stage 46 as the object beam. The other beam, adjusted to a specific beam propagation direction, serves as the reference beam. After passing through first reflector 47, second reflector 48, and aperture 49, it is incident on the other side of the three-axis translation stage 46. The two beams interfere with the photosensitive material fixed to the three-axis translation stage 46, recording the phase information of the object beam on the HOE film, thereby fabricating the HOE film.

[0046] In the aforementioned related technologies, the performance of the HOE film can only be tested through optical testing after exposure. However, due to the deviation and distortion of the propagation angles and phases of the object light and reference light after the beam shrinkage, as well as the uneven distribution of the laser light output intensity, platform vibration, air disturbances and other factors, the object light phase information recorded on the HOE film after exposure deviates from the designed object light phase information, resulting in low HOE film processing accuracy and low processing efficiency.

[0047] Based on this, if the interference fringes produced by the interference of the object light and the reference light can be obtained before the actual exposure operation on the photosensitive material, the difference between the interference fringes and the reference interference fringes can be determined at this time, and then the phase of the object light can be adjusted until the difference between the interference fringes produced by the interference of the adjusted object light and the reference light and the reference interference fringes is within a preset range. The phase of the object light at this time is used as the target phase, and the photosensitive material is actually exposed based on the object light and reference light with the target phase. At this time, the interference fringes recorded on the photosensitive material are interference fringes whose difference from the reference interference fringes is within the preset range, thereby eliminating the influence of the above-mentioned multiple error factors and improving the exposure accuracy and efficiency of the holographic optical element.

[0048] Among them, in order to obtain the interference fringes produced by the interference of object light and reference light, a Michelson interferometer can be used. Figure 5 A schematic diagram of the structure of a Michelson interferometer, see Figure 5 As shown, laser light emitted from laser 51 is split by collimating lens 52 and beam splitter 53. The two beams are then reflected by mirrors mounted on two-axis translation stages 54 and 55, respectively. The two beams interfere at right-side lens 56, and interference fringes are observed on a translucent white screen 57. In the HOE film exposure optical path, the phase information carried by the object light can be calculated based on the interference fringes and the incident angle of the reference light.

[0049] Based on the aforementioned Michelson interferometer, the present application provides a holographic optical element exposure device, system, and method. The holographic optical element exposure device includes an exposure module and a feedback module. The exposure module includes a laser and an exposure light path. The exposure light path splits the laser light emitted by the laser to generate a first object beam and a first reference beam for exposing a photosensitive material, as well as a second object beam and a second reference beam for detecting interference fringes and implementing feedback.

[0050] The feedback module has some functions of a Michelson interferometer and is used to obtain a feedback image of the first interference fringes generated by the interference of the second object light and the second reference light, and feed the feedback image back to the control device so that the control device adjusts the phase of the object light until the difference between the distribution of the first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes is within a preset range. The phase of the object light at this time is used as the target phase and output, so that the holographic optical element exposure device actually exposes the photosensitive material according to the object light with the target phase, thereby improving the accuracy and efficiency of the exposure of the holographic optical element.

[0051] In one implementation scenario, the HOE film can be used in a head-up display device, which can be used in vehicles, such as the automotive field, the marine field, etc. Take the automotive field as an example, please refer to Figure 6 As shown, Figure 6This is a schematic diagram of an application scenario for a head-up display device provided in an embodiment of the present application. The head-up display device can project important driving information such as speed and navigation information onto a distant area outside the windshield in front of the driver. The corresponding image can be seen in front of the windshield, making it easy for the driver to directly observe the speed, revs, gear position, navigation, and other driving information without having to look down or turn around. The HOE film can be located on the car's windshield.

[0052] The following detailed description of the technical solution of the present application is provided in conjunction with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0053] Figure 7 A schematic diagram of the structure of a holographic optical element exposure device provided in an embodiment of the present application Figure 1 ,refer to Figure 7 As shown, the holographic optical element exposure device 70 includes: an exposure module 71 and a feedback module 72;

[0054] The exposure module 71 includes a laser 711 and an exposure optical path 712. The laser 711 is used to emit laser light, and the exposure optical path 712 is used to receive the phase sent by the control device. The laser light is split to obtain object light and reference light. The phase of the object light is the phase sent by the control device, and includes a first object light and a second object light. The reference light includes a first reference light and a second reference light. The first object light and the first reference light are used to interfere to expose the photosensitive material to obtain a holographic optical element. The second object light and the second reference light are used to interfere to generate first interference fringes.

[0055] The feedback module 72 is configured to obtain a feedback image including the first interference fringes, and send the feedback image to a control device, so that the control device adjusts the phase of the object light based on the feedback image, and sends the adjusted phase to the exposure optical path 712 until the difference between the distribution of the first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes falls within a preset range, and output a target phase of the object light, so as to expose the photosensitive material according to the object light with the target phase;

[0056] The distribution of the reference interference fringes is calculated by the control device based on the first reference light and the first object light with an initial phase.

[0057] In some embodiments, the initial phase is the phase information of the object light to be recorded on the photosensitive material. It can be a phase value input by a user into a control device, or it can be determined by the control device based on optical design indicators input by the user. Specifically, the initial phase is obtained based on the optical design indicators through an iterative algorithm or geometric optical design software. The optical design indicators include at least one of the following: field of view, resolution, image distance, and distortion.

[0058] In the HUD application scenario, the optical design indicators are the field of view angle, resolution, image distance and distortion corresponding to the far-field virtual image observed by the human eye through the windshield.

[0059] In related technologies, the holographic optical element is exposed directly based on the object light and reference light of the initial phase. However, due to the influence of various error factors, there is a certain deviation between the object light phase information recorded on the photosensitive material and the initial phase, that is, the object light phase information recorded on the photosensitive material is not the initial phase of the object light.

[0060] Since the first interference fringes generated by the interference of the second object light and the second reference light are consistent with the interference fringes generated by the first object light and the first reference light, the phase information of the object light can be detected in real time at the holographic optical element, i.e., the photosensitive material, based on the first interference fringes.

[0061] Based on the feedback module 72 of the present application, a feedback image including the first interference fringes is acquired and sent to a control device. In one implementation scenario, the control device may determine the distribution of the first interference fringes based on the feedback image and compare the distribution of the first interference fringes with the distribution of the reference interference fringes. If the difference between the two is not within a preset range, that is, the distribution of the first interference fringes differs significantly from the distribution of the reference interference fringes, the phase of the second object light that produces the first interference fringes may be adjusted. The adjusted second object light and the second reference light interfere again, and the feedback module 72 acquires a feedback image of the current first interference fringes again. The above process is repeated until the distribution of the first interference fringes and the distribution of the reference interference fringes are within the preset range.

[0062] Because the distribution of the reference interference fringes is calculated by the control device based on the first reference beam and the first object beam at the initial phase, the distribution of the reference interference fringes is not affected by error factors. In other words, the reference interference fringes can be considered to be the result of interference between the first object beam and the first reference beam at the initial phase, assuming no error. If the reference interference fringes are irradiated onto a photosensitive material, the phase information recorded on the photosensitive material is the initial phase.

[0063] When the distribution of the first interference fringes and the distribution of the reference interference fringes are within a preset range, indicating a small difference between the two, the phase of the second object light that produces the first interference fringes is used as the target phase, and the phase of the first object light is the same as the phase of the second object light. The first object light with the target phase interferes with the first reference light. Under the influence of various error factors, the interference fringes produced at the photosensitive material are the first interference fringes whose distribution difference from the reference interference fringes is within the preset range. Therefore, the object light phase information at this time at the photosensitive material is the desired initial phase.

[0064] It should be noted that before determining the target phase of the object light, it is not necessary to place a photosensitive material in the exposure module 71. After determining the target phase of the object light, a photosensitive material can be placed in the exposure module 71 and exposed to the photosensitive material using the first object light and the first reference light at the target phase, so that the object light phase information recorded on the photosensitive material is the initial phase.

[0065] It should also be noted that Figure 7 The laser 711 and exposure optical path 712 shown in the figure, and the exposure optical path 712 and feedback module 72 are connected by dotted lines, which are only used to indicate the transmission path of the light beam, and do not indicate the actual connection relationship between the laser 711 and exposure optical path 712, and the exposure optical path 712 and feedback module 72.

[0066] The present application provides a holographic optical element exposure device 70, comprising an exposure module 71 and a feedback module 72. The exposure module 71 comprises a laser 711 and an exposure optical path 712. The laser 711 emits laser light. The exposure optical path 712 is used to receive the phase sent by the control device and also split the laser light to obtain object light and reference light. The object light comprises a first object light and a second object light, and the reference light comprises a first reference light and a second reference light. The first object light and the first reference light are used to expose a photosensitive material to obtain a holographic optical element. The second object light and the second reference light interfere to generate first interference fringes. Based on the feedback module 72 in the present application, a feedback image including the first interference fringes is obtained in real time and fed back to the control device so that the control device modulates the phase of the object light until the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range. The control device takes the phase of the object light at this time as the target phase and outputs it, so that the holographic optical element exposure device 70 exposes the photosensitive material according to the object light of the target phase, so that the object light information recorded by the photosensitive material is the required initial phase, eliminating the influence of various error factors and improving the accuracy and efficiency of the holographic optical element exposure.

[0067] Figure 8 This is a structural diagram of an exposure module provided in an embodiment of the present application. In one or more embodiments of the present application, reference is made to Figure 8As shown, the exposure optical path 712 includes a first beam splitter 7121, a first translation stage 7122, an object light path 7123 and a reference light path 7124;

[0068] The first beam splitter 7121 is located at the light output side of the laser 711 and is used to split the laser to obtain a first light beam L1 and a reference light R, and to direct the first light beam L1 into the object light path 7123 and the reference light R into the reference light path 7124;

[0069] The object light path 7123 is used to receive the phase sent by the control device, apply the phase to the first light beam L1, and obtain the corresponding object light O; split the object light O to obtain the first object light O1 and the second object light O2, and emit the first object light O1 to one side of the first translation stage 7122, and emit the second object light O2 to the feedback module 72;

[0070] The reference light path 7124 is used to split the reference light R to obtain a first reference light R1 and a second reference light R2, and emit the first reference light R1 to the other side of the first translation stage 7122, and emit the second reference light R2 to the feedback module 72;

[0071] The first translation stage 7122 is used to place photosensitive materials.

[0072] In one implementation scenario, since the first translation stage 7122 is used to place the photosensitive material, in order to achieve exposure of the entire area of ​​the photosensitive material, the first translation stage 7122 may be a three-dimensional translation stage.

[0073] In some embodiments, the exposure optical path 712 may further include a first stepper motor 7125 connected to a first translation stage 7122. When preparing a holographic optical element, a photosensitive material is mounted and fixed on the first translation stage 7122. The first stepper motor 7125 is used to control the first translation stage 7122 to move in steps, so that the photosensitive material on the first translation stage 7122 is exposed step by step, thereby achieving complete exposure of the HOE film.

[0074] It should be noted that before the target phase of the object light is determined, no photosensitive material is placed on the first translation stage 7122. After the target phase of the object light is determined, a fixed photosensitive material can be mounted on the first translation stage 7122 and exposed based on the object light of the target phase.

[0075] In some embodiments, a collimating lens 713 may be provided between the laser 711 and the first beam splitter 7121. The collimating lens 713 is used to collimate the laser light emitted by the laser 711 to obtain a parallel laser beam, and then emit the parallel laser beam to the first beam splitter 7121 for splitting.

[0076] In some embodiments, the object light path 7123 includes a spatial light modulator 301 and a second beam splitter 302 ;

[0077] The spatial light modulator 301 is configured to receive the phase signal sent by the control device, apply the phase signal to the incident first light beam L1, obtain the corresponding object light O, and emit the object light O to the second beam splitter 302;

[0078] The second beam splitter 302 is located on the light output side of the spatial light modulator 301 and is used to split the object light O to obtain a first object light O1 and a second object light O2, and emit the first object light O1 to one side of the first translation stage 7122 and emit the second object light O2 to the feedback module 72.

[0079] The spatial light modulator 301 is connected to the control device and is used to receive the phase sent by the control device. When the first light beam L1 passes through the spatial light modulator 301, the phase of the object light O obtained is the phase sent by the control device.

[0080] In some embodiments, the object light path 7123 further includes a first lens assembly 303 and a second lens assembly 304;

[0081] The first lens assembly 303 is located between the first beam splitter 7121 and the spatial light modulator 301 and is used to reduce the first light beam L1;

[0082] The second lens assembly 304 is located between the spatial light modulator 301 and the second beam splitter 302 , and is used to reduce the object light O.

[0083] In one implementation scenario, the first lens assembly 303 and the second lens assembly 304 may also be referred to as a telescope system, each including two lenses with different focal lengths.

[0084] In related technologies, when the HOE film area is large, free-form surfaces, aspheric surfaces, diffractive optical elements, etc. are used to obtain the object light. However, these elements are difficult to manufacture over a large area with high precision. Using dynamic phase modulators such as SLMs results in large pixel sizes and low resolution. Therefore, the present application utilizes a second lens assembly 304 to focus the object light output by the SLM 301, which helps improve the resolution of the object light phase distribution and achieve high-precision manufacture of the HOE film.

[0085] In some embodiments, the reference light path 7124 includes a first reflecting mirror 401 , a second reflecting mirror 402 , and a third beam splitter 403 ;

[0086] The first reflecting mirror 401 is used to receive the reference light R emitted by the first beam splitter 7121 and reflect the reference light R to the third beam splitter 403;

[0087] The third beam splitter 403 is located between the first reflecting mirror 401 and the first translation stage 7122, and is used to split the reference light R into a first reference light R1 and a second reference light R2, and emit the first reference light R1 to the other side of the first translation stage 7122, and emit the second reference light R2 to the second reflecting mirror 402;

[0088] The second reflector 402 is configured to emit the second reference light R2 to the feedback module 72 .

[0089] The first reflector 401 and the second reflector 402 are respectively used to change the transmission direction of the incident light, so that the reference light R is incident on the third beam splitter 403 in a specific propagation direction after passing through the first reflector 401, and the second reference light R2 is also incident on the feedback module 72 in a specific propagation direction after passing through the second reflector 402.

[0090] In one implementation scenario, the reference light path 7124 may further include an aperture to limit the size of the first reference light R1 incident on the other side of the first translation stage 7122 .

[0091] In summary, in the exposure optical path 712, the laser is split based on the first beam splitter 7121 to obtain a first light beam L1 and a reference light R. The incident first light beam L1 is modulated based on the spatial light modulator 301 to obtain an object light O. The object light O is split based on the second beam splitter 302 to obtain a first object light O1 and a second object light O2. The reference light R is split based on the third beam splitter 403 to obtain a first reference light R1 and a second reference light R2, wherein the first object light O1 and the first reference light R1 are used to expose the photosensitive material, and the second object light O2 and the second reference light R2 are used to generate first interference fringes, so as to realize feedback through the feedback module 72 and adjust the object light phase. At the same time, the object light O emitted by the spatial light modulator 301 can be narrowed by the second lens assembly 304, which effectively improves the resolution of the object light phase distribution and achieves higher preparation accuracy.

[0092] Figure 9 A schematic diagram of the structure of a feedback module provided in an embodiment of the present application, referring to Figure 9As shown, in one or more embodiments of the present application, the feedback module 72 includes a third reflector 721, a fourth beam splitter 722, a second translation stage 723, a first lens 724, a screen 725 and a sensor 726;

[0093] The third reflector 721 is used to reflect the second object light O2 emitted from the second beam splitter 302 to the fourth beam splitter 722;

[0094] The fourth beam splitter 722 is used to split the second reference light R2 emitted by the second reflector 402 and the incident second object light O2, and emit part of the second reference light to the first lens 724, and emit part of the second object light to the second translation stage 723, and then reflect the second object light to the fourth beam splitter 722 through the reflector on the second translation stage 723, and then reflect the second object light to the first lens 724 through the fourth beam splitter 722;

[0095] The first lens 724 is used to converge the portion of the second reference light and the portion of the second object light so as to cause the portion of the second reference light and the portion of the second object light to interfere with each other, and the generated first interference fringes are displayed on the screen 725;

[0096] The sensor 726 is located on a side of the screen 725 away from the first lens 724 and is used to capture the first interference fringes displayed on the screen 725 to obtain a feedback image and send the feedback image to a control device.

[0097] In one implementation scenario, a camera may be used as the sensor 726 to capture the first interference fringes displayed on the screen 725 to obtain a feedback image.

[0098] The screen 725 is used to present the first interference fringes and may be a semi-transparent white screen.

[0099] In some embodiments, the feedback module 72 further includes a second stepper motor 727 connected to the second translation stage 723 for controlling the movement of the second translation stage 723. The movement of the second translation stage 723 changes the optical path length of the portion of the second object light incident on the second translation stage 723.

[0100] In one implementation scenario, if the second translation stage 723 is close to the fourth beam splitter 722, after the second object light O2 passes through the fourth beam splitter 722, the distance of part of the second object light incident on the second translation stage 723 is shortened. Similarly, after being reflected by the second translation stage 723, the distance of the second object light incident on the fourth beam splitter 722 again is also shortened, so the optical path of part of the second object light is reduced.

[0101] In another implementation scenario, if the second translation stage 723 is away from the fourth beam splitter 722, after the second object light O2 passes through the fourth beam splitter 722, the distance of part of the second object light incident on the second translation stage 723 increases. Similarly, after being reflected by the second translation stage 723, the distance of the second object light incident on the fourth beam splitter 722 again also increases, so the optical path of part of the second object light increases.

[0102] The second translation stage 723 may be a two-dimensional translation stage, and specifically, may be moved in a direction approaching or away from the fourth beam splitter 722 .

[0103] In some embodiments, in order to ensure that part of the second object light and part of the second reference light interfere with each other and the generated first interference fringes are relatively clear, when designing the holographic optical element exposure device 70, a fiber optic spectrometer can also be used to measure the spectral signal of the first interference fringes. The optical path difference between part of the second object light and part of the second reference light that generate the first interference fringes is analyzed by spectral carrier frequency. Based on the optical path difference between the two, the second translation stage 723 is precisely moved to achieve nanometer-level precise matching of the optical path.

[0104] Among them, the interference spectra of different optical path differences can be referred to Figures 10 to 13 As shown, Figure 10 This is a schematic diagram of the interference fringe spectrum signal corresponding to an optical path difference of 60 microns provided in an embodiment of the present application. The vertical axis represents the relative intensity of light, and the horizontal axis represents the frequency of light. Figure 11 A schematic diagram of the interference fringe spectrum signal corresponding to an optical path difference of 30 microns provided in an embodiment of the present application is provided. Figure 12 A schematic diagram of the interference fringe spectrum signal corresponding to an optical path difference of 10 microns provided in an embodiment of the present application is provided. Figure 13 A schematic diagram of the interference fringe spectrum signal corresponding to an optical path difference of less than 100 nanometers provided in an embodiment of the present application.

[0105] Depend on Figures 10 to 13 It can be seen that when the optical path difference gradually decreases, the period of the interference spectrum carrier signal gradually decreases until the carrier signal disappears. When the signal envelope is smooth, the optical path difference is less than 100nm, achieving precise matching of the two optical paths.

[0106] When using a fiber optic spectrometer for measurement, the fiber optic spectrometer can be placed Figure 9 The screen 725 is shown in the figure. It should be noted that since the fiber optic spectrometer is required when designing the holographic optical element exposure device 70, after the fiber optic spectrometer achieves optical path matching between the portion of the second object light and the portion of the second reference light that generate the first interference fringes, the fiber optic spectrometer can be removed and devices such as the screen 725 and the sensor 726 can be placed.

[0107] In some embodiments, in addition to the optical path difference, the first interference fringe is also related to the light intensity of the two light beams that generate the interference. Figure 14 A schematic diagram of the structure of a holographic optical element exposure device provided in an embodiment of the present application Figure 2 ,refer to Figure 14 As shown, in one implementation scenario, the holographic optical element exposure device 70 further includes an attenuation plate 73;

[0108] The attenuation plate 73 is located between the second reflector 402 and the fourth beam splitter 722, or between the third beam splitter 403 and the second reflector 402, and is used to attenuate the intensity of the second reference light R2;

[0109] or,

[0110] The attenuation plate 73 is located between the third reflector 721 and the fourth beam splitter 722 , or between the second beam splitter 302 and the third reflector 721 , and is configured to attenuate the intensity of the second object light O2 .

[0111] In some embodiments, when designing the holographic optical element exposure apparatus 70 , an optical power meter may be used to measure the intensities of the second reference light R2 and the second object light O2 incident on the fourth beam splitter 722 .

[0112] When performing measurement, the optical power meter can be placed between the second reflector 402 and the fourth beam splitter 722, or between the third beam splitter 403 and the second reflector 402, to measure the intensity of the second reference light R2; the optical power meter can be placed between the third reflector 721 and the fourth beam splitter 722, or between the second beam splitter 302 and the third reflector 721, to measure the intensity of the second object light O2.

[0113] In one implementation scenario, if the intensity of the second reference light R2 is greater than the intensity of the second object light O2, the intensity of the second reference light R2 needs to be attenuated. Therefore, an attenuation plate 73 can be placed between the second reflector 402 and the fourth beam splitter 722, or between the third beam splitter 403 and the second reflector 402, so that the intensity of the second reference light R2 and the intensity of the second object light O2 are within a preset intensity difference range.

[0114] Figure 14 The attenuation plate 73 shown in FIG. 7 is located between the second reflector 402 and the fourth beam splitter 722 , which is only illustrated as an example and does not fully illustrate the position of the attenuation plate 73 .

[0115] In another implementation scenario, if the intensity of the second object light O2 is greater than the intensity of the second reference light R2, the intensity of the second object light O2 needs to be attenuated. Therefore, an attenuation plate 73 can be placed between the third reflector 721 and the fourth beam splitter 722, or between the second beam splitter 302 and the third reflector 721, so that the intensity of the second object light O2 and the intensity of the second reference light R2 are within a preset intensity difference range.

[0116] Attenuation plates with different optical densities are used to match the intensities of the second object light O2 and the second reference light R2. The attenuation plate 73 included in the holographic optical element exposure device 70 is the attenuation plate 73 that corresponds to the intensities of the two beams. After determining the required attenuation plate 73, the optical power meter can be removed.

[0117] In summary, based on the feedback module 72, a feedback image including the first interference fringes can be obtained in real time, and the feedback image can be sent to the control device. The control device can adjust the phase of the object light according to the feedback image until the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range. The phase of the object light is adjusted by feedback to achieve closed-loop control, which is beneficial to improving the preparation accuracy and efficiency of the holographic optical element.

[0118] Figure 15 The process of a holographic optical element exposure method provided in the embodiment of the present application Figure 1 The method is applied to a control device, which may be a computer or other device, and is not limited in this application. Figure 15 As shown, the holographic optical element exposure method may include:

[0119] S1501: Receive a feedback image including first interference fringes sent by a holographic optical element exposure device.

[0120] S1502: Adjust the phase of the object light based on the feedback image, and send the adjusted phase to the exposure light path in the holographic optical element exposure device until the difference between the distribution of the first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes is within a preset range, and output the target phase of the object light to expose the photosensitive material according to the object light with the target phase.

[0121] The target phase is the phase of the object light that generates the first interference fringes when the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range;

[0122] The distribution of the reference interference fringes is calculated by the control device based on the first reference light and the first object light with an initial phase;

[0123] The object light includes the first object light and the second object light. The first object light and the first reference light are used to interfere with each other to expose the photosensitive material and obtain the holographic optical element. The second object light and the second reference light are used to interfere with each other to generate first interference fringes.

[0124] Since the two beams incident on the fourth beam splitter 722, namely the second object beam and the second reference beam, need to be orthogonal, and the angle between the first object beam and the first reference beam is θ, it is necessary to compensate for the difference in the angle θ between the first reference beam and the first object beam through tilted phase superposition. The difference is 90°-θ. Therefore, when calculating the distribution of the reference interference fringes based on the first reference beam and the first object beam at the initial phase, the first reference beam needs to be coherently superimposed with a blazed grating phase with a blazed angle of 90°-θ. The expression for the blazed grating phase can be shown as follows:

[0125]

[0126] in, represents the phase of the blazed grating, θ is the angle between the first reference light and the first object light, λ is the wavelength of the first reference light or the first object light, and the two wavelengths are consistent, and x is the pixel coordinate of the spatial light modulator.

[0127] In some embodiments, adjusting the phase of the object light based on the feedback image and sending the adjusted phase to an exposure optical path in the holographic optical element exposure device until a difference between the distribution of first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes falls within a preset range, and outputting a target phase of the object light includes:

[0128] Repeat the following steps until the fidelity of the first interference fringe and the reference interference fringe is greater than a preset threshold, and output the target phase of the object light:

[0129] determining, based on the feedback image, a distribution of first interference fringes included in the feedback image;

[0130] determining, based on the distribution of the first interference fringes and the distribution of the reference interference fringes, the fidelity of the first interference fringes and the reference interference fringes, wherein the fidelity is used to characterize the difference between the first interference fringes and the reference interference fringes;

[0131] If the fidelity is less than a preset threshold, the phase of the first object light is adjusted, and the adjusted phase is sent to the spatial light modulator 301 in the holographic optical element exposure device to obtain object light of corresponding phase.

[0132] Fidelity is used to characterize the difference between the first interference fringe and the reference interference fringe. A greater fidelity indicates a smaller difference between the first and reference interference fringe, meaning they are more similar. One method for calculating fidelity is to multiply the conjugate value of the reference interference fringe distribution by the measured first interference fringe distribution, perform a two-dimensional integration, and use the modulus as the numerator and the two-dimensional integral of the modulus of the two interference fringe distributions as the denominator. The ratio of the two is the fidelity of the interference fringe. The calculation method is as follows:

[0133]

[0134] Among them, F is the fidelity, A0(x,y) is the distribution of the reference interference fringes, and A t (x, y) is the distribution of the first interference fringe, and x and y represent the spatial coordinates of a point in the interference fringe.

[0135] In one implementation scenario, the preset threshold may be 97%, and the distortion design tolerance may be 3%, which may be adjusted according to actual needs and is not limited in this application.

[0136] When the fidelity is less than a preset threshold, the phase of the second object beam can be adjusted based on the optimization algorithm for pre-distortion, and the optimized and adjusted phase of the second object beam is output again to the spatial light modulator 301. Through continuous feedback and iteration, until the fidelity exceeds the preset threshold, that is, the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range, the phase of the second object beam that produces the first interference fringes is used as the target phase of the object beam. Under the influence of various error factors, the phase of the first object beam actually output to the photosensitive material can be made close to the desired initial phase.

[0137] In addition to using the fidelity to determine the degree of difference between the distribution of the first interference fringes and the distribution of the reference interference fringes, other methods may also be used for determination, such as standard deviation, etc., which is not limited in this application.

[0138] After determining the target phase, a fixed photosensitive material can be mounted on the first translation stage 7122, and the object light phase within the unit area can be sequentially loaded onto the spatial light modulator 301. Based on the first translation stage 7122, the photosensitive material is controlled to move stepwise to the corresponding position, and the exposure of the complete holographic optical element is achieved through step-by-step exposure.

[0139] It should be noted that the phase of the object light, the phase of the first object light, and the phase of the second object light are the same.

[0140] The first translation stage 7122 and the spatial light modulator 301 and other devices are all included in the holographic optical element exposure device. The structure and principle of the holographic optical element exposure device can be referred to the above embodiment and will not be described in detail here.

[0141] It should also be noted that the holographic optical element exposure method of the present application is applicable to the processing and preparation of various types of holographic optical elements, including but not limited to volume holographic waveguides, HOE films, etc.

[0142] An embodiment of the present application provides a holographic optical element exposure method. Based on a feedback image including first interference fringes sent by a holographic optical element exposure apparatus, the phase of the object light is adjusted based on the feedback image, and the modulated phase is sent to an exposure light path in the holographic optical element exposure apparatus to change the phase of the object light until the difference between the distribution of first interference fringes generated by second object light and second reference light and the distribution of reference interference fringes is within a preset range. The phase of the object light at this time is used as a target phase and output. A photosensitive material is exposed according to the target phase. Under the influence of various error factors, the interference fringes obtained by interference on the photosensitive material are first interference fringes whose distribution is within a preset range with respect to the distribution of the reference interference fringes. That is, the phase recorded on the photosensitive material is the desired initial phase, thereby improving the accuracy and efficiency of holographic optical element exposure.

[0143] Based on the above embodiment, a specific embodiment is provided below to describe in detail the process of the control device determining the target phase of the object light.

[0144] Figure 16 The process of a holographic optical element exposure method provided in the embodiment of the present application Figure 2 , the method is executed by the control device, reference Figure 16 As shown, the method may include:

[0145] S1601: Receive the initial phase of the object light input by the user.

[0146] S1602: Based on the object light and the reference light at the initial phase, calculate the distribution of the reference interference fringes, and execute step S1605.

[0147] S1603: Send the phase of the object light to the spatial light modulator, so that after the first light beam passes through the spatial light modulator, an object light with a corresponding phase is obtained.

[0148] The phase of the object light includes the initial phase and the phase optimized in step S1606. After the phase of the object light is sent to the spatial light modulator, the spatial light modulator loads the corresponding phase. After the first light beam passes through the spatial light modulator, an object light with the corresponding phase can be obtained.

[0149] When the phase of the object light sent to the spatial light modulator changes, the phase of the object light obtained after the first light beam passes through the spatial light modulator will also change accordingly.

[0150] S1604: Receive a feedback image including first interference fringes from the sensor and determine the distribution of the first interference fringes. The first interference fringes are generated by the interference of the second object light and the second reference light. The generation principles of the second object light and the second reference light can be found in the above embodiment and will not be further described here.

[0151] S1605: Calculate the fidelity based on the distribution of the reference interference fringes and the distribution of the first interference fringes, and determine whether the fidelity is less than a preset threshold.

[0152] S1606: If yes, optimize the phase of the current object light and execute step S1603.

[0153] Since the distribution of the first interference fringes is related to the phase of the second object light, when the phase of the object light changes, that is, the phase of the second object light changes, the distribution of the first interference fringes will also change accordingly.

[0154] S1607: If not, the phase of the object light at this time is used as the target phase and output.

[0155] In summary, the control device adjusts the phase of the object light based on the feedback image, and through continuous feedback and iteration, the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is made to be within a preset range, and the target phase of the object light is determined. Then, when the first object light and the first reference light of the target phase are used to expose the photosensitive material, under the influence of various error factors, the phase of the object light recorded on the photosensitive material is the required initial phase, thereby eliminating the influence of the error factors and improving the exposure accuracy and efficiency of the holographic optical element.

[0156] Figure 17 This is a schematic diagram of the structure of a holographic optical element exposure system provided in an embodiment of the present application, with reference to Figure 17 As shown, the holographic optical element exposure system includes a control device 80 and the holographic optical element exposure apparatus 70 described in any one of the above embodiments.

[0157] The control device 80 is connected to the sensor 726 and the spatial light modulator 301 respectively.

[0158] Figure 18 This is a schematic diagram of the structure of a control device provided in this application. Figure 18 As shown, the device includes: a receiving module 1801 and a processing module 1802.

[0159] The receiving module 1801 is configured to receive a feedback image including first interference fringes sent by a holographic optical element exposure device;

[0160] a processing module 1802 for adjusting the phase of the object light based on the feedback image, and sending the adjusted phase to an exposure optical path in the holographic optical element exposure device until the difference between the distribution of first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes falls within a preset range, and outputting a target phase of the object light, so as to expose the photosensitive material according to the object light with the target phase;

[0161] The target phase is the phase of the object light that generates the first interference fringes when the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range;

[0162] The distribution of the reference interference fringes is calculated by the control device based on the first reference light and the first object light with an initial phase;

[0163] The object light includes the first object light and the second object light. The first object light and the first reference light are used to interfere with each other to expose the photosensitive material and obtain the holographic optical element. The second object light and the second reference light are used to interfere with each other to generate first interference fringes.

[0164] The control device provided in the embodiment of the present application can execute the holographic optical element exposure method in the above method embodiment, and its implementation principle and technical effect are similar, which will not be described in detail here. Figure 18 The division of the modules shown is only a schematic illustration, and this application does not limit the division of the modules and the naming of the modules.

[0165] Figure 19 A schematic diagram of a control device provided in an embodiment of the present application. Figure 19 As shown, an embodiment of the present application provides a control device 1900 including a processor 1901 and a memory 1902 , wherein the processor 1901 and the memory 1902 are connected via a bus 1903 .

[0166] During the specific implementation process, the memory 1902 stores codes, and the processor 1901 runs the codes stored in the memory 1902 to execute the method of the above method embodiment.

[0167] The specific implementation process of processor 1901 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0168] The present application also provides a computer-readable storage medium, which may include: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, and other media that can store program codes. Specifically, the computer-readable storage medium stores program instructions, and the program instructions are used for the methods in the above embodiments.

[0169] The present application also provides a program product, comprising execution instructions stored in a readable storage medium. At least one control module of a display device can read the execution instructions from the readable storage medium, and at least one control module executes the execution instructions to cause the display device to implement the holographic optical element exposure method provided in the various embodiments described above.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0171] For ease of explanation, the above description has been made with reference to specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations are possible. The above embodiments are selected and described to better explain the principles and practical applications, so that those skilled in the art can better utilize the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A holographic optical element exposure device, characterized in that: The holographic optical element exposure device includes: an exposure module and a feedback module; The exposure module includes a laser and an exposure optical path, wherein the laser is used to emit laser light, and the exposure optical path is used to receive a phase sent by a control device; the laser light is split to obtain object light and reference light; the object light has a phase sent by the control device and includes a first object light and a second object light; the reference light includes a first reference light and a second reference light; the first object light and the first reference light are used to interfere with each other to expose a photosensitive material to obtain a holographic optical element; the second object light and the second reference light are used to interfere with each other to generate first interference fringes; The feedback module is configured to obtain a feedback image including the first interference fringes, and send the feedback image to a control device, so that the control device adjusts the phase of the object light based on the feedback image, and sends the adjusted phase to the exposure optical path until the difference between the distribution of the first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes is within a preset range, and output a target phase of the object light, so as to expose the photosensitive material according to the object light with the target phase; The distribution of the reference interference fringes is calculated by the control device based on the first reference light and the first object light with an initial phase.

2. The holographic optical element exposure apparatus according to claim 1, wherein: The exposure optical path includes a first beam splitter, a first translation stage, an object light path and a reference light path; The first beam splitter is located at the light output side of the laser, and is used to split the laser to obtain a first light beam and a reference light, and to input the first light beam into the object light path and the reference light into the reference light path; The object light path is used to receive the phase sent by the control device, and load the phase onto the first light beam to obtain the corresponding object light; Splitting the object light to obtain a first object light and a second object light, and emitting the first object light to one side of the first translation stage, and emitting the second object light to the feedback module; The reference light path is used to split the reference light to obtain a first reference light and a second reference light, and emit the first reference light to the other side of the first translation stage, and emit the second reference light to the feedback module; The first translation stage is used for placing photosensitive materials.

3. The holographic optical element exposure apparatus according to claim 2, wherein: The object light path includes a spatial light modulator and a second beam splitter; The spatial light modulator is used to receive the phase sent by the control device, apply the phase to the incident first light beam, obtain corresponding object light, and emit the object light to the second beam splitter; The second beam splitter is located on the light output side of the spatial light modulator, and is used to split the object light to obtain a first object light and a second object light, and emit the first object light to one side of the first translation stage, and emit the second object light to the feedback module.

4. The holographic optical element exposure apparatus according to claim 3, wherein: The object light path further includes a first lens assembly and a second lens assembly; The first lens assembly is located between the first beam splitter and the spatial light modulator, and is used to reduce the first light beam; The second lens assembly is located between the spatial light modulator and the second beam splitter, and is used to reduce the object light.

5. The holographic optical element exposure apparatus according to claim 3, wherein: The reference light path includes a first reflecting mirror, a second reflecting mirror and a third beam splitter; The first reflecting mirror is used to receive the reference light emitted by the first beam splitter and reflect the reference light to the third beam splitter; The third beam splitter is located between the first reflector and the first translation stage, and is used to split the reference light to obtain a first reference light and a second reference light, and emit the first reference light to the other side of the first translation stage, and emit the second reference light to the second reflector; The second reflector is used to emit the second reference light to the feedback module.

6. The holographic optical element exposure apparatus according to claim 5, wherein: The feedback module includes a third reflector, a fourth beam splitter, a second translation stage, a first lens, a screen and a sensor; The third reflecting mirror is used to reflect the second object light emitted by the second beam splitter to the fourth beam splitter; The fourth beam splitter is used to split the second reference light emitted by the second reflector and the incident second object light, and emit part of the second reference light to the first lens, and emit part of the second object light to the second translation stage, and then reflect the second object light to the fourth beam splitter through the reflector located on the second translation stage, and then reflect the second object light to the first lens through the fourth beam splitter; The first lens is used to converge the portion of the second reference light and the portion of the second object light so as to cause the portion of the second reference light and the portion of the second object light to interfere with each other, and the generated first interference fringes are displayed on the screen; The sensor is located on a side of the screen away from the first lens, and is used to capture the first interference fringes displayed on the screen to obtain a feedback image, and send the feedback image to a control device.

7. The holographic optical element exposure apparatus according to claim 6, wherein: The holographic optical element exposure device further includes an attenuation plate; The attenuation plate is located between the second reflector and the fourth beam splitter, or between the third beam splitter and the second reflector, and is used to attenuate the intensity of the second reference light; or, The attenuation plate is located between the third reflector and the fourth beam splitter, or between the second beam splitter and the third reflector, and is used to attenuate the intensity of the second object light.

8. A holographic optical element exposure system, characterized in that: The holographic optical element exposure system comprises a control device and the holographic optical element exposure apparatus according to any one of claims 1 to 7.

9. A holographic optical element exposure method, characterized in that: Applied to control equipment, including: receiving a feedback image including first interference fringes sent by a holographic optical element exposure device; adjusting the phase of the object light based on the feedback image, and sending the adjusted phase to an exposure optical path in the holographic optical element exposure device until a difference between the distribution of first interference fringes generated by the second object light and the second reference light and the distribution of the reference interference fringes falls within a preset range, outputting a target phase of the object light, and exposing a photosensitive material according to the object light with the target phase; The target phase is the phase of the object light that generates the first interference fringes when the difference between the distribution of the first interference fringes and the distribution of the reference interference fringes is within a preset range; The distribution of the reference interference fringes is calculated by the control device based on the first reference light and the first object light with an initial phase; The object light includes the first object light and the second object light. The first object light and the first reference light are used to interfere with each other to expose the photosensitive material and obtain the holographic optical element. The second object light and the second reference light are used to interfere with each other to generate first interference fringes.

10. The method according to claim 9, characterized in that The method further comprises: adjusting the phase of the object light based on the feedback image, sending the adjusted phase to an exposure optical path in the holographic optical element exposure device, and outputting a target phase of the object light until a difference between a distribution of first interference fringes generated by the second object light and the second reference light and a distribution of reference interference fringes falls within a preset range. The method further comprises: Repeat the following steps until the fidelity of the first interference fringe and the reference interference fringe is greater than a preset threshold, and output the target phase of the object light: determining, based on the feedback image, a distribution of first interference fringes included in the feedback image; determining, based on the distribution of the first interference fringes and the distribution of the reference interference fringes, the fidelity of the first interference fringes and the reference interference fringes, wherein the fidelity is used to characterize the difference between the first interference fringes and the reference interference fringes; If the fidelity is less than a preset threshold, the phase of the first object light is adjusted, and the adjusted phase is sent to the spatial light modulator in the holographic optical element exposure device to obtain object light of corresponding phase.

Images