Detection system and method

Abstract

The invention discloses a detection system and method. The system comprises a first light splitting element, first detection equipment, a linear array photoelectric receiving device and an interference element. In the detection system, a first beam of light from an optical element is divided into first transmission light and first reflection light through a first light splitting element; the first detection equipment can detect the light intensity change value of the first reflected light, and the light intensity change value of the first reflected light is used for representing the diffraction efficiency of the optical element; the interference element can receive the first transmission light and obtain and project interference fringes, so that the linear array photoelectric receiving device can obtain image information of the interference fringes, and the image information is used for representing the refractive index variation of the optical element. Therefore, the diffraction efficiency and the refractive index variation of the optical element are detected, the performance of the optical element can be evaluated, and the process of the optical element can be improved.

Description

A detection system and method Technical Field

[0001] The present application relates to the field of optical technology, and in particular to a detection system and method. Background Art

[0002] With the rapid development of modern optical and optoelectronic technologies, optoelectronic instruments and their components have undergone profound and significant changes. Optical components are no longer limited to refractive lenses, prisms, and mirrors. New optical elements such as microlens arrays, diffractive optical elements, and gradient-index lenses are increasingly being used in various optoelectronic instruments, enabling further miniaturization, array-based design, and integration of optoelectronic instruments and their components.

[0003] Among them, the principles of some optical elements (for example, holographic optical elements (HOE)) are based on the interference and diffraction of light waves. Therefore, the performance of these optical elements can be evaluated by parameters such as diffraction efficiency and refractive index change.

[0004] In summary, how to measure the diffraction efficiency and refractive index change of optical elements to evaluate the performance of optical elements and thus improve the process of optical elements is a technical problem that needs to be solved urgently in this field.

[0005] Summary of the Invention

[0006] The present application provides a detection system and method for measuring the diffraction efficiency and refractive index change of an optical element, thereby evaluating the performance of the optical element and helping to improve the process of the optical element.

[0007] In a first aspect, embodiments of the present application provide a detection system comprising a first spectroscopic element, a first detection device, a linear array photoelectric receiving device, and an interference element. The first spectroscopic element can be used to split a first beam of light from an optical element into a first transmitted light and a first reflected light; the first detection device can be used to detect a change in the intensity of the first reflected light, which is used to characterize the diffraction efficiency of the optical element; the interference element can be used to receive the first transmitted light and obtain and project interference fringes; and the linear array photoelectric receiving device can be used to obtain image information of the interference fringes, which is used to characterize the change in the refractive index of the optical element.

[0008] It should be noted that "projected interference fringes" can be understood as projecting interference fringes onto the receiving screen, "the intensity change value of the first reflected light is used to characterize the diffraction efficiency of the optical element" can be understood as the intensity change value of the first reflected light is used to determine the diffraction efficiency of the optical element, and "image information is used to characterize the refractive index change of the optical element" can be understood as the image information is used to determine the refractive index change of the optical element.

[0009] Based on the above detection system, a first beam of light from an optical element is split into a first transmitted light and a first reflected light by a first beam splitter. A first detection device can then detect the intensity change of the first reflected light, which is used to characterize the diffraction efficiency of the optical element. An interference element can receive the first transmitted light, generate interference fringes, and project the fringes. A linear array photoelectric receiving device can then capture image information of the interference fringes, which is used to characterize the refractive index change of the optical element. This enables detection of both the diffraction efficiency and refractive index change of the optical element, enabling evaluation of its performance and contributing to improvements in its manufacturing process.

[0010] In one possible design, the optical element is a holographic optical element (HOE), and accordingly, the first beam of light is holographic light. In this design, the holographic light from the HOE can be split, thereby measuring the diffraction efficiency and refractive index change of the HOE, thereby evaluating the performance of the HOE.

[0011] In one possible design, the system may further include a first light source, a polarization beam splitter, a first shutter, a second shutter, and a control device; wherein the first light source may be used to output a second beam of light; the polarization beam splitter may be used to split the second beam of light when the first shutter is open to obtain a third beam of light and a fourth beam of light; the control device may be used to control the second shutter to open so that the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is open, thereby exposing the HOE. In this design, after the second beam of light output by the first light source is split by the polarization beam splitter, the second shutter is controlled to open so that the third beam of light and the fourth beam of light obtained after the split are incident on the HOE when the second shutter is open, thereby exposing the HOE. In this way, by controlling the first shutter and the second shutter, exposure control of the HOE can be achieved, effectively simplifying the exposure optical path of the HOE, and making the exposure optical path of the HOE simple to implement.

[0012] In one possible design, the control device can also be used to control the second shutter to close according to a preset cycle. While the second shutter is closed, the third beam of light illuminates the HOE to produce holographic light. In this design, the control device controls the second shutter to close according to a preset cycle, so that the third beam of light illuminates the HOE when the second shutter is closed, thereby producing holographic light. This eliminates the need to add a new optical path to generate holographic light, further effectively simplifying the HOE's exposure optical path, making it compact and simple to implement.

[0013] In one possible design, the system may further include a second light source and a third shutter. The second light source can be used to output a seventh beam of light. The control device can also be used to control the opening of the third shutter. When the third shutter is open, the seventh beam of light illuminates the HOE, generating holographic light. The seventh beam of light propagates in the same direction as the third beam of light. In this design, the second light source and third shutter add a new optical path to generate holographic light. The control device then controls the opening of the third shutter, allowing the seventh beam of light generated by the second light source to illuminate the HOE when the third shutter is open, generating holographic light. This simplifies control of the second shutter by the control device.

[0014] In one possible design, the system further includes a second beam splitter, a first beam expander, and a second beam expander; the first beam expander can be used to expand the third beam to obtain an expanded third beam; the second beam splitter can be used to split the fourth beam to obtain a fifth beam and a sixth beam; and the second beam expander can be used to expand the fifth beam to obtain an expanded fifth beam. Accordingly, the third and fourth beams are incident on the HOE when the second shutter is open to expose the HOE, including: the expanded third beam and the expanded fifth beam are incident on the HOE when the second shutter is open to expose the HOE. In this design, the third beam is expanded by the first beam expander, the fourth beam is split by the second beam splitter to obtain a fifth beam, and the fifth beam is expanded by the second beam expander. Then, the expanded third and fifth beams are controlled to be incident on the HOE when the second shutter is open to expose the HOE. In this way, the exposure effect of HOE is improved, which helps to improve the exposure process of HOE.

[0015] In one possible design, the system further includes a second detection device; when controlling the opening of the second shutter so that the third and fourth light beams are incident on the HOE when the second shutter is open, and exposing the HOE, the control device is specifically configured to: receive first information from the second detection device, the first information indicating that the intensity change value of the sixth light beam is within a preset range; and control the opening of the second shutter so that the expanded third and fifth light beams are incident on the HOE when the second shutter is open, and exposing the HOE. It is understood that "the intensity change value of the sixth light beam is within the preset range" means that the second light beam output by the first light source is stable, and thus the third and fourth light beams obtained by splitting the second light beam are also stable, that is, the two light beams used to expose the HOE are stable. Therefore, in this design, the control device only controls the HOE to begin exposure after determining that the two light beams used to expose the HOE are stable, making the HOE exposure process more stable and helping to improve the accuracy of HOE performance evaluation.

[0016] In one possible design, the second detection device can be used to detect whether the intensity variation of the sixth light beam is within a preset range. When the intensity variation of the sixth light beam is within the preset range, the first information is sent to the control device. In this design, the second detection device detects the intensity variation of the sixth light beam to determine the stability of the second light beam output by the first light source, thereby facilitating the control device to control the exposure process of the HOE.

[0017] In one possible design, the control device can also be configured to control the first shutter to close when the diffraction efficiency reaches a first threshold and / or when a first parameter of the interference fringes reaches a second threshold; the first parameter includes width, shape, or brightness contrast. In this design, the control device controls the HOE exposure process based on the HOE's diffraction efficiency and / or the first parameter of the interference fringes, ensuring that the HOE exposure control meets the user's experimental requirements.

[0018] In one possible design, when the third and fourth beams of light expose the HOE, the third and fourth beams of light can be incident on different sides of the HOE, or the third and fourth beams of light can be incident on the same side of the HOE. It should be noted that in the embodiment of the present application, the third and fourth beams of light can be incident on different sides of the HOE, that is, a reflective exposure light path is formed; the third and fourth beams of light can be incident on the same side of the HOE, that is, a transmissive exposure light path is formed. In this design, a transmissive exposure light path and a reflective exposure light path of the HOE are provided, so that the exposure light path provided in the embodiment of the present application can be flexibly implemented.

[0019] In one possible design, the first beam expanding element or the second beam expanding element includes a spatial light filter and a lens.

[0020] In one possible design, the first beam expanding element or the second beam expanding element includes a lens and an off-axis reflector.

[0021] In a possible design, the linear array photoelectric receiving device is a charge coupled device (CCD) camera or a complementary metal oxide semiconductor (CMOS) camera.

[0022] In second aspect, an embodiment of the present application provides a detection method, which includes: a first spectroscopic element splits a first beam of light from an optical element into a first transmitted light and a first reflected light; a first detection device detects a light intensity change value of the first reflected light, and the light intensity change value of the first reflected light is used to characterize the diffraction efficiency of the optical element; an interference element receives the first transmitted light, obtains and projects the interference fringes; a linear array photoelectric receiving device obtains image information of the interference fringes, and the image information is used to characterize the refractive index change of the optical element.

[0023] In a possible design, the optical element is a holographic optical element (HOE), and the first beam of light is holographic light.

[0024] In one possible design, the method further includes: when the first shutter is opened, the polarization splitter element splits the second beam of light to obtain a third beam of light and a fourth beam of light; wherein the second beam of light is output by the first light source; and the control device controls the second shutter to open so that the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

[0025] In one possible design, the method further includes: a control device controls the second shutter to close according to a preset period, and when the second shutter is closed, the third beam of light irradiates the HOE to obtain the holographic light.

[0026] In one possible design, the method further includes: controlling the third shutter to open by a control device so that the seventh beam of light illuminates the HOE when the third shutter is opened to obtain the holographic light; wherein the seventh beam of light is output by the second light source, and the propagation direction of the seventh beam of light is the same as that of the third beam of light.

[0027] In one possible design, the method further includes: a first beam expander expands the third beam of light to obtain an expanded third beam of light; a second beam splitter splits the fourth beam of light to obtain a fifth beam of light and a sixth beam of light; the second beam expander expands the fifth beam of light to obtain an expanded fifth beam of light; the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, and the HOE is exposed, including: the expanded third beam of light and the expanded fifth beam of light are incident on the HOE when the second shutter is opened, and the HOE is exposed.

[0028] In one possible design, the control device controls the second shutter to open so that the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, thereby exposing the HOE, including: the control device receives first information from a second detection device, and the first information indicates that the intensity change value of the sixth beam of light is within a preset range; the control device controls the second shutter to open so that the third beam of light after expansion and the fifth beam of light after expansion are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

[0029] In a possible design, before the control device controls the second shutter to open, the method further includes: detecting, by the second detection device, whether a change in the intensity of the sixth light beam is within the preset range;

[0030] The second detection device sends the first information to the control device when the light intensity change value of the sixth light beam is within the preset range.

[0031] In one possible design, the method further includes: the control device controls the first shutter to close when the diffraction efficiency reaches a first threshold and / or when the first parameter of the interference fringes reaches a second threshold; wherein the first parameter includes width, shape or brightness contrast.

[0032] For the beneficial effects of the method described in the above-mentioned second aspect and any optional design of the second aspect, please refer to the relevant description in the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1A is a schematic diagram of a HOE applicable to an embodiment of the present application;

[0034] FIG1B is a second schematic diagram of the principle of the HOE applicable to the embodiment of the present application;

[0035] FIG2 is a schematic structural diagram of an exposure light path;

[0036] FIG3 is a schematic diagram of a possible structure of a detection system provided in an embodiment of the present application;

[0037] FIG4 is a schematic diagram of another possible structure of the detection system provided in an embodiment of the present application;

[0038] FIG5 is a schematic diagram of another possible structure of the detection system provided in an embodiment of the present application;

[0039] FIG6 is a schematic diagram of another possible structure of the detection system provided in an embodiment of the present application;

[0040] FIG7 is a schematic diagram of another possible structure of the detection system provided in an embodiment of the present application;

[0041] FIG8 is a schematic diagram of another possible structure of the detection system provided in an embodiment of the present application;

[0042] FIG9 is a schematic diagram showing changes in the diffraction efficiency of the HOE provided in an embodiment of the present application;

[0043] FIG10 is a schematic diagram of interference fringes of an HOE provided in an embodiment of the present application;

[0044] FIG11 is a schematic diagram of a flow chart of exposure control of an HOE according to an embodiment of the present application;

[0045] FIG12 is a flow chart of the detection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0047] First, some of the terms used in this application are explained. It should be noted that these explanations are for the purpose of facilitating understanding by those skilled in the art and are not intended to limit the scope of protection claimed in this application.

[0048] 1. Object light.

[0049] The object light is a beam emitted by a coherent light source, and the amplitude and phase information corresponding to the beam need to be recorded through a holographic optical element.

[0050] 2. Reference light.

[0051] The reference light is a beam coherent with the object light, and the phase and amplitude of the reference light and the object light can be the same. Optionally, in some embodiments, the reference light can be expanded before being incident on the holographic element.

[0052] 3. Reappearance of light.

[0053] The reproduction light is a beam used to reproduce the amplitude and phase information of the object light. In some possible embodiments, the reproduction light can be a reference light. In other possible embodiments, the reproduction light is generated by a newly added light source.

[0054] 4. Holographic light.

[0055] Holographic light is a light beam obtained by irradiating a holographic optical element (HOE) with reproduced light and has the same phase and amplitude as the object light.

[0056] Furthermore, for ease of understanding, the exposure principle of HOE is introduced below.

[0057] Currently, HOE exposure methods include transmission and reflection.

[0058] As shown in Figure 1A, in the transmission exposure method, the object light and the reference light are irradiated from the same side of the HOE at a preset angle △θ to expose the HOE, and the phase information and amplitude information of the object light are recorded into the HOE material; then the reference light is used as the reproduction light to irradiate the HOE alone along the exposure direction, and its transmitted light will propagate in the propagation direction of the object light to form a holographic light.

[0059] As shown in Figure 1B, in the reflective exposure method, the object light and the reference light are irradiated from different sides of the HOE according to a preset angle △θ to expose the HOE, and the phase information and amplitude information of the object light are recorded into the HOE material; then the reference light is used as the reproduction light to irradiate the HOE alone along the exposure direction, and its reflected light will propagate in the propagation direction of the object light to form a holographic light.

[0060] In order to evaluate the performance of the HOE, some technical solutions propose to detect the exposure parameters of the HOE.

[0061] As shown in FIG2 , in some technical solutions, two spectroscopes (i.e., spectroscope 4 and spectroscope 5) are used to split the light beam provided by light source 1 into object light b1, reference light b2, and probe light b3. By adjusting object light b1 and reference light b2, object light b1 and reference light b2 are irradiated from the same side of HOE 9 to expose HOE 9. The probe light b3 is further adjusted to become the conjugate light b4 of reference light b2, and the conjugate light b4 is used as the reproduction light to irradiate HOE 9 separately to obtain holographic light b5. The plane mirror 10 reflects the holographic light b5 to the optical power meter 11, and then the optical power meter 11 can measure the diffraction efficiency of HOE 9. However, in this technical solution, the exposure light path is large in volume, the implementation is complex, and it can only measure the diffraction efficiency of HOE 9, but not the refractive index change of HOE 9, resulting in low accuracy in the performance evaluation of HOE.

[0062] Other technical solutions measure the change in the HOE's refractive index after exposure. However, this solution cannot measure the change in the HOE's refractive index in real time, nor can it measure the HOE's diffraction efficiency, resulting in low accuracy in evaluating the HOE's performance.

[0063] Therefore, in the above technical solution, it is impossible to simultaneously detect the change in the diffraction efficiency and the refractive index of the optical element, resulting in low accuracy in the performance evaluation of the HOE.

[0064] In view of this, the present application proposes a detection system and method, which includes a first spectroscopic element, a first detection device, a linear array photoelectric receiving device, and an interference element. In this system, the first spectroscopic element splits a first beam of light from an optical element into a first transmitted light and a first reflected light. The first detection device can then detect the intensity change of the first reflected light, which is used to characterize the diffraction efficiency of the optical element. The interference element can receive the first transmitted light, obtain and project interference fringes, and the linear array photoelectric receiving device can then obtain image information of the interference fringes, which is used to characterize the refractive index change of the optical element. In this way, the diffraction efficiency and refractive index change of the optical element can be measured, and the performance of the optical element can be evaluated, which helps improve the process of the optical element.

[0065] For example, please refer to Figure 3, which shows a possible structural schematic diagram of the detection system provided in an embodiment of the present application. The detection system 300 includes a first spectroscopic element 301, a first detection device 302, a linear array photoelectric receiving device 303 and an interference element 304. In Figure 3, the detection system 300 is used to measure the refractive index change and diffraction efficiency of the optical element 100. The first spectroscopic element 301 can be used to split the first beam of light A1 from the optical element 100 into a first transmitted light A2 and a first reflected light A3. The first detection device 302 can be used to detect the intensity change value of the first reflected light A3, and the intensity change value of the first reflected light A3 is used to characterize the diffraction efficiency of the optical element. The interference element 304 can be used to receive the first transmitted light A2, obtain and project interference fringes. The linear array photoelectric receiving device 303 can be used to obtain image information of the interference fringes, and the image information is used to characterize the refractive index change of the optical element.

[0066] In the above-described detection system 300, a first beam of light from an optical element is split into a first transmitted light and a first reflected light by a first beam splitter. A first detection device can then detect the intensity change of the first reflected light, which is used to characterize the diffraction efficiency of the optical element. An interference element can receive the first transmitted light, generate interference fringes, and project the fringes. A linear array photoelectric receiving device can then capture image information of the interference fringes, which is used to characterize the refractive index change of the optical element. This enables detection of both the diffraction efficiency and refractive index change of the optical element, enabling evaluation of its performance and contributing to improvements in its manufacturing process.

[0067] It should be noted that “projecting interference fringes” can be understood as projecting interference fringes onto a receiving screen (as shown in FIG3 ).

[0068] It should also be noted that "the intensity change value of the first reflected light A3 is used to characterize the diffraction efficiency of the optical element" can be understood as the intensity change value of the first reflected light A3 being used to determine the diffraction efficiency of the optical element. "The intensity change value of the first reflected light A3" can be understood as the difference between the intensity values ​​of the first reflected light A3 at the start and end of a preset time period.

[0069] In some possible embodiments, the first detection device 302 has computing capabilities, and thus the first detection device 302 can determine the diffraction efficiency of the optical element according to the intensity change value of the first reflected light A3.

[0070] In other possible embodiments, the first detection device 302 does not have computing capabilities, but the above-mentioned detection system 300 also includes a control device 306 (as shown in Figure 4). The first detection device 302 can send the light intensity change value of the first reflected light A3 to the control device 306, and then the control device 306 can determine the diffraction efficiency of the optical element based on the light intensity change value of the first reflected light A3.

[0071] It should also be noted that "image information is used to characterize the refractive index change of an optical element" can be understood as the use of image information to determine the refractive index change of the optical element. In other words, the change in the interference fringes can be used to characterize the change in the refractive index change of the optical element. For example, the sharper the interference fringes or the more curved the interference fringes, the greater the refractive index change.

[0072] In some possible embodiments, the linear array photoelectric receiving device 303 has a computing capability, and thus the linear array photoelectric receiving device 303 can determine the refractive index change of the optical element according to the image information.

[0073] In other possible embodiments, the first detection device 302 does not have computing capabilities, but the above-mentioned detection system 300 also includes a control device 306 (as shown in Figure 4). The first detection device 302 can send the image information to the control device 306, and then the control device 306 can determine the refractive index change of the optical element based on the image information.

[0074] The following describes each functional module and structure shown in FIG3 , and provides an exemplary specific implementation scheme.

[0075] 1. First Beam Splitting Element 301

[0076] In the embodiment of the present application, the first beam splitting element 301 may be any element having a beam splitting function. As a possible implementation, the first beam splitting element 301 may be a beam splitter or a diffractive optical element (DOE), which is not specifically limited in the embodiment of the present application.

[0077] 2. First Detection Device 302

[0078] In the embodiment of the present application, the first detection device 302 may be any device capable of detecting light intensity. As a possible implementation, the first detection device 302 may be an optical power meter.

[0079] 3. Linear Array Photoelectric Receiver 303

[0080] In the embodiment of the present application, linear array photoelectric receiving device 303 can be any element capable of acquiring image information. As a possible implementation, linear array photoelectric receiving device 303 can be a charge coupled device (CCD) camera or a complementary metal oxide semiconductor (CMOS) camera, which is not specifically limited in the embodiment of the present application.

[0081] 4. Interference Element 304

[0082] In the embodiment of the present application, the interference element 304 may be any element having an interference function. As a possible implementation, the interference element 304 may be a flat glass or a plane mirror.

[0083] 5. Optical Components 100

[0084] In the embodiments of the present application, optical element 100 is the optical element to be measured. Optical element 100 can be any optical element whose performance parameters to be measured are diffraction efficiency and refractive index variation. As a possible implementation, optical element 100 can be an HOE or other optical diffraction element, which is not specifically limited in the embodiments of the present application.

[0085] It should be noted that when the above-mentioned optical element 100 is an HOE, the first beam of light can be a holographic light generated by the HOE. In the examples below, the optical element 100 is taken as an HOE to introduce the detection system 300 provided in the embodiment of the present application. Furthermore, when the above-mentioned optical element 100 is an HOE, the detection system 300 provided in the embodiment of the present application can also include an exposure light path, and then the detection system 300 can detect the exposure process of the HOE, realize the detection of the diffraction efficiency and refractive index change of the HOE, thereby improving the exposure efficiency of the HOE and improving the exposure process.

[0086] For example, see Figure 4, which shows another possible structural diagram of a detection system provided in an embodiment of the present application. In Figure 4, detection system 300 also includes an exposure light path 305 and a control device 306. Exposure light path 305 includes a first light source, a polarization beam splitter, a first shutter, and a second shutter.

[0087] As shown in Figure 4, in a possible embodiment, the first shutter is arranged between the first light source and the polarization splitter element, and the second shutter is arranged after the polarization splitter element; the first light source can be used to output the second light beam B1, and the control device 306 can control the first shutter to open so that the second light beam B1 can be received by the polarization splitter element; then the polarization splitter element can split the second light beam B1 to obtain a third light beam B2 and a fourth light beam B3; and the control device 306 can control the second shutter to open so that the third light beam B2 and the fourth light beam B3 are incident on the HOE when the second shutter is opened to expose the HOE.

[0088] It should be noted that, in the embodiment of the present application, the control device 306 can be any chip or integrated circuit with computing capabilities. For example, the control device 306 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0089] It should also be noted that in the embodiments of the present application, the first light source may be a laser or other light source, without limitation herein. The laser may be, for example, at least one of an edge emitting laser (EEL), a vertical-cavity surface-emitting laser (VCSEL), or a fiber laser.

[0090] It should also be noted that, in the embodiment of the present application, the polarization beam splitter element is also referred to as a polarizing beam splitter (PBS). As a possible implementation, the polarization beam splitter element can be a polarization beam splitter prism. Furthermore, if the polarization beam splitter element is a polarization beam splitter prism, when the polarization beam splitter element splits the second light beam B1, the obtained third light beam B2 and fourth light beam B3 are two perpendicular linearly polarized lights, that is, the third light beam B2 is P-polarized light, and the fourth light beam B3 is S-polarized light. Therefore, the exposure optical path 305 also includes a half-wave plate 1, which can modulate the fourth light beam B3 and convert the fourth light beam B3 into P-polarized light.

[0091] It should be noted that in the embodiment of the present application, the third beam of light B2 and the fourth beam of light B3 are incident on the HOE when the second shutter is opened. When the HOE is exposed, there are multiple ways to implement the structure of the exposure light path. Two situations are introduced below.

[0092] Case 1: Reflective exposure light path.

[0093] For example, please continue to refer to FIG. 4 . When the third light beam B2 and the fourth light beam B3 expose the HOE, the third light beam B2 and the fourth light beam B3 are incident on different sides of the HOE, forming a reflective exposure light path.

[0094] Case 2: Transmissive exposure light path.

[0095] For example, referring to FIG. 5 , when the third light beam B2 and the fourth light beam B3 expose the HOE, the third light beam B2 and the fourth light beam B3 are incident on the same side of the HOE, forming a transmissive exposure light path.

[0096] The above scenarios 1 and 2 provide a transmissive exposure light path and a reflective exposure light path of the HOE, so that the exposure light path provided in the embodiment of the present application can be flexibly implemented.

[0097] Please refer to Figure 6, which shows another possible structural diagram of the detection system provided by the embodiment of the present application. In Figure 6, the exposure light path 305 in the detection system 300 can also include a second beam splitter, a first beam expander D1, and a second beam expander D2. The first beam expander D1 can be used to expand the third light beam B2 to obtain the expanded third light beam B2. 1 The second beam splitter element can be used to split the fourth light beam B3 to obtain the fifth light beam B4 and the sixth light beam B5; the second beam expander element D2 can be used to expand the fifth light beam B4 to obtain the expanded fifth light beam B4 1 .

[0098] Correspondingly, after the third beam B2 is obtained 1 and the fifth beam B4 after beam expansion 1 In this case, the third light beam B2 and the fourth light beam B3 are incident on the HOE when the second shutter is opened to expose the HOE, including: the third light beam B21 after expansion and the fifth light beam B41 after expansion are incident on the HOE when the second shutter is opened to expose the HOE.

[0099] It should be noted that, in the embodiment of the present application, the first beam expander D1 or the second beam expander D2 can control the field of view of the light beam (for example, the divergence angle of the light beam, the spot size, etc.). For example, the first beam expander D1 is used to expand the spot of the third light beam B2 to obtain the expanded third light beam B2. 1 For another example, the second beam expander D2 can be used to expand the spot of the fifth light beam B4 to obtain the expanded fifth light beam B4. 1 .

[0100] It should be understood that there are many ways to implement the first beam expander D1 or the second beam expander D2, including but not limited to the following:

[0101] In mode 1, the first beam expanding element D1 or the second beam expanding element D2 may include a spatial light filter and a lens.

[0102] In mode 2, the first beam expanding element D1 or the second beam expanding element D2 may include a lens and an off-axis reflector (also called a curved reflector).

[0103] For example, please continue to refer to Figure 6. In Figure 6, the first beam expander D1 may include a spatial light filter and a lens, and the second beam expander D2 may include a lens and an off-axis reflector. It should be understood that in other possible embodiments, the first beam expander D1 may include a lens and an off-axis reflector, and the second beam expander D2 may include a spatial light filter and a lens. This embodiment of the present application is not specifically limited.

[0104] It should also be noted that, in the embodiment of the present application, the second light splitting element can be any element having a light splitting function. As a possible implementation, the second light splitting element can be a spectroscope or a DOE, which is not specifically limited in the embodiment of the present application.

[0105] In Figure 6, the third light beam is expanded by the first beam expander, and the fourth light beam is split by the second beam splitter to obtain a fifth light beam, which is then expanded by the second beam expander. The expanded third and fifth light beams are then incident on the HOE when the second shutter is open, achieving exposure of the HOE. This amplifies the spot and / or divergence angle of the third and fourth light beams, thereby improving the exposure effect of the HOE and helping to improve the exposure process of the HOE.

[0106] Please refer to FIG7 , which shows another possible structural diagram of the detection system provided in an embodiment of the present application. In FIG7 , the detection system 300 further includes a second detection device 307 .

[0107] As shown in FIG7 , in one possible implementation, after the second beam splitter element splits the fourth light beam B3 to generate the sixth light beam B5, the second detection device 307 can detect whether the intensity change of the sixth light beam B5 is within a preset range. When the intensity change of the sixth light beam B5 is within the preset range, the second detection device 307 sends the first information to the control device 306. For example, the preset range can be any one of [0, 2%], [0, 0.1%], or [0, 0.05%], and this embodiment of the present application does not impose any specific limitation.

[0108] In an embodiment of the present application, the second detection device 307 may be any device having a function of detecting light intensity. As a possible implementation method, the second detection device 307 may be an optical power meter. It can be understood that "the light intensity change value of the sixth beam of light is within a preset range" can be used to characterize that the second beam of light B1 output by the first light source is stable, and then the third beam of light B2 and the fourth beam of light B3 obtained by splitting the second beam of light B1 by the PBS are also stable, that is, the two beams used to expose the HOE are stable. In this way, the control device controls the HOE to start exposure only when it determines that the two beams used to expose the HOE are stable, so that the exposure process of the HOE is more stable, which helps to improve the accuracy of the performance evaluation of the HOE.

[0109] In FIG7 , by detecting the intensity change value of the sixth beam of light by the second detection device 307 , the stability of the second beam of light output by the first light source can be determined, thereby facilitating the control device 306 to control the exposure process of the HOE.

[0110] Accordingly, in a possible embodiment, the control device 306 is used to control the second shutter to open so that the third light beam B2 and the fourth light beam B3 are incident on the HOE when the second shutter is opened to expose the HOE, including: the control device 306 can receive the first information from the second detection device 307, if the first information indicates that the intensity change value of the sixth light beam B5 is within a preset range, the control device 306 controls the second shutter to open so that the expanded third light beam B2 1 and the fifth beam B4 after beam expansion 1 When the second shutter is open, light enters the HOE and exposes the HOE. In this way, the control device 306 controls the second shutter only when it determines that the second light beam B1 emitted by the first light source is stable, thereby achieving exposure control of the HOE and making the exposure process of the HOE more stable.

[0111] The above describes the exposure optical path in the detection system provided by the embodiment of the present application. The following describes the optical path for HOE to generate holographic light. The following uses the reflective exposure optical path as an example to introduce the method for generating holographic light provided by the embodiment of the present application.

[0112] In the first embodiment, the control device 306 may control the second shutter to close according to a preset period, so that when the second shutter is closed, the second beam of light irradiates the HOE to obtain holographic light.

[0113] For example, referring to FIG. 4 , the control device 306 may further control the second shutter to close according to a preset period, so that when the second shutter is closed, the third light beam B2 illuminates the HOE to produce holographic light A1 (i.e., the first light beam). The preset period may be any one of 1s, 50ms, and 10ms, and is not specifically limited in this embodiment of the present application.

[0114] In the first embodiment, the second shutter is closed by controlling the control device 306 so that the third beam of light is used as the reproduction light to illuminate the HOE, so that the optical path volume of the detection system 300 is small, the implementation is simple, and the cost of the detection system 300 is effectively reduced.

[0115] In the second embodiment, a second light source is added to the detection system 300 , and the HOE is illuminated by the seventh light beam output by the second light source to obtain holographic light.

[0116] For example, please refer to FIG8 , which shows another possible structural diagram of the detection system provided in an embodiment of the present application. In FIG8 , the detection system 300 further includes a second light source and a third shutter. The second light source can be used to output a seventh light beam C1; the control device 306 can control the third shutter to open so that the seventh light beam C1 illuminates the HOE when the third shutter is open, thereby obtaining holographic light A1 (i.e., the first light beam); the seventh light beam C1 has the same propagation direction as the third light beam B2.

[0117] It should be noted that "the seven light beams C1 and the third light beam B2 have the same propagation direction" can be understood as the angle between the optical axes of the seven light beams C1 and the third light beam B2 being less than a threshold. The threshold value can be, for example, 0.01, so that the seventh light beam C1 can be used as the reproduction light to illuminate the HOE to generate the holographic light A1 (i.e., the first light beam). In addition, in the embodiment of the present application, the second light source can be a laser or other light source, which is not limited here.

[0118] Optionally, FIG8 may further include a third beam expander D3, which may expand the seventh beam C1 to obtain the expanded seventh beam C1. 1 Then the control device 306 can control the third shutter to open, so that the seventh beam C1 after expansion 1 When the third shutter is opened, the HOE is illuminated to obtain the holographic light A1 (i.e. the first beam of light). Similarly, the seventh beam of light C1 after expansion 1 The propagation direction is the same as that of the third light beam B2. 1 The generated holographic light A1 (ie, the first beam of light) has a better effect. The specific implementation of the third beam expander D3 is similar to that of the first beam expander D1, which can be found in the previous text and will not be described again here.

[0119] In the second embodiment, a second light source and a third shutter are added to the detection system 300. The control device controls the opening of the third shutter, so that the seventh light beam generated by the second light source illuminates the HOE when the third shutter is open, generating holographic light. This simplifies the control of the second shutter by the control device.

[0120] It should be noted that the detection system 300 provided in the embodiment of the present application can not only realize the real-time detection of the exposure parameters during the exposure process of the HOE, but also further control the exposure process of the HOE to improve the exposure process. Among them, there are many ways to implement the detection system 300 to control the exposure process of the HOE, including but not limited to the following implementations:

[0121] In embodiment 1, the control device 306 may control the first shutter to close when the diffraction efficiency of the HOE reaches a first threshold.

[0122] It should be noted that, as shown in Figure 4, after the control device 306 controls the first shutter to close, the second beam of light B1 generated by the first light source cannot reach the polarization splitter element, and then the polarization splitter element cannot obtain the third beam of light B2 and the fourth beam of light B3, thereby causing the third beam of light B2 and the fourth beam of light B3 to stop exposing the HOE.

[0123] In embodiment 1, the control device 306 can determine that the diffraction efficiency of the HOE reaches the first threshold based on the curve of the diffraction efficiency of the HOE changing with the exposure time as shown in Figure 9, and control the first shutter to close and stop exposing the HOE, so that the exposure control of the HOE is more in line with the user's experimental needs.

[0124] In embodiment 2, the control device 306 may control the first shutter to close when the first parameter of the interference fringes reaches a second threshold.

[0125] The first parameter includes, but is not limited to, width, shape, or brightness contrast. It is understood that "width" refers to the width of the interference fringes, "shape" refers to the curvature of the interference fringes (for example, the interference fringes can be circular or have other shapes), and "brightness contrast" refers to the brightness contrast of the interference fringes (i.e., the contrast between black and white as shown in FIG10 ). The greater the brightness contrast, the clearer the interference fringes. In other words, the control device 306 may control the first shutter to close when the width of the interference fringes reaches a second threshold; alternatively, the control device 306 may control the first shutter to close when the curvature of the interference fringes changes to a maximum; alternatively, the control device 306 may control the first shutter to close when the brightness contrast of the interference fringes reaches a maximum.

[0126] It should be noted that the first parameter of the interference fringes is related to the change in the refractive index of the HOE. For example, the greater the change in the refractive index, the clearer the interference fringes and the more curved the interference fringes. Therefore, in embodiment 2, the control device 306 controls the first shutter to close and stop exposing the HOE based on the first parameter of the interference fringes (i.e., combined with the change in the refractive index of the HOE), so that the exposure of the HOE better meets the user's experimental needs.

[0127] In embodiment 3, the control device 306 may further control the first shutter to close when the diffraction efficiency reaches a first threshold value and when the first parameter of the interference fringes reaches a second threshold value.

[0128] In embodiment 3, the diffraction efficiency and refractive index variation of the HOE are combined to control the first shutter to close and stop exposing the HOE, so that the exposure control of the HOE is more precise.

[0129] Furthermore, in one possible embodiment, the control device 306 can also perform exposure control based on the priority of the HOE exposure performance when the intensity change value of the sixth light beam is within a preset range (i.e., when the second light beam output by the first light source is stable). For example, as shown in FIG11 , the second detection device 307 is an optical power meter 1, and the first detection device 302 is an optical power meter 2. Accordingly, the optical power meter 1 can collect the intensity change value of the sixth light beam, and the optical power meter 2 can collect the diffraction efficiency of the HOE.

[0130] In Figure 11, the exposure control process includes the following steps:

[0131] S1101 , the control device 306 controls the first shutter to open.

[0132] S1102 : The optical power meter 1 collects the intensity change value of the sixth light beam.

[0133] S1103 : The control device 306 determines whether the light intensity change value of the sixth light beam is within a preset range.

[0134] S1104 : The control device 306 determines the exposure performance priority of the HOE.

[0135] If the diffraction efficiency of the HOE is prioritized, the control device 306 executes S1105A; if the refractive index change amount of the HOE is prioritized, the control device 306 executes S1105B.

[0136] S1105A: Perform exposure control based on the diffraction efficiency of the HOE.

[0137] S1105B, perform exposure control based on the refractive index change of HOE.

[0138] S1106 : The control device 306 controls the first shutter to close.

[0139] Among them, S1105A further includes the following steps:

[0140] A1. Start exposing the HOE.

[0141] A2. The control device 306 controls the second shutter to close.

[0142] A3. Optical power meter 2 collects diffraction efficiency.

[0143] A4. The control device 306 determines whether the diffraction efficiency reaches a first threshold.

[0144] If the diffraction efficiency does not reach the first threshold, the control device 306 executes step A5; if the diffraction efficiency reaches the first threshold, the control device 306 executes S1106.

[0145] A5. The control device 306 controls the second shutter to open.

[0146] Wherein, S1105B further includes the following steps:

[0147] B1. Start exposing the HOE.

[0148] B2. The control device 306 controls the second shutter to close.

[0149] B3. CCD camera collects image information of interference fringes.

[0150] B4. The control device 306 determines whether the first parameter of the interference fringes reaches a second threshold.

[0151] If the first parameter of the interference fringes reaches the second threshold, the control device 306 executes S1106 ; if the first parameter of the interference fringes does not reach the second threshold, the control device 306 executes step B5 .

[0152] B5. The control device 306 controls the second shutter to open.

[0153] Based on the above content and the same concept, the embodiment of the present application further provides a detection method, which is performed by the detection system 300 shown in Figure 3. Referring to Figure 12, the method includes:

[0154] S1201 : The first beam splitting element 301 splits the first light beam from the optical element 100 into a first transmitted light and a first reflected light.

[0155] S1202 : The first detection device 302 detects a light intensity change value of the first reflected light, where the light intensity change value of the first reflected light is used to characterize the diffraction efficiency of the optical element.

[0156] S1203 : The interference element 304 receives the first transmitted light and obtains interference fringes.

[0157] S1204 , the interference element 304 projects interference fringes.

[0158] For example, the interference element 304 may project interference fringes onto a receiving screen.

[0159] S1205 , the linear array photoelectric receiving device 303 can be used to obtain image information of interference fringes, and the image information is used to characterize the refractive index change of the optical element.

[0160] In a possible design, the optical element is a holographic optical element (HOE), and the first beam of light is holographic light.

[0161] In one possible design, the method further includes: when the first shutter is opened, the polarization splitter element splits the second beam of light to obtain a third beam of light and a fourth beam of light; wherein the second beam of light is output by the first light source; and the control device controls the second shutter to open so that the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

[0162] In one possible design, the method further includes: a control device controls the second shutter to close according to a preset period, and when the second shutter is closed, the third beam of light irradiates the HOE to obtain the holographic light.

[0163] In one possible design, the method further includes: controlling the third shutter to open by a control device so that the seventh beam of light illuminates the HOE when the third shutter is opened to obtain the holographic light; wherein the seventh beam of light is output by the second light source, and the propagation direction of the seventh beam of light is the same as that of the third beam of light.

[0164] In one possible design, the method further includes: a first beam expander expands the third beam of light to obtain an expanded third beam of light; a second beam splitter splits the fourth beam of light to obtain a fifth beam of light and a sixth beam of light; the second beam expander expands the fifth beam of light to obtain an expanded fifth beam of light; the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, and the HOE is exposed, including: the expanded third beam of light and the expanded fifth beam of light are incident on the HOE when the second shutter is opened, and the HOE is exposed.

[0165] In one possible design, the control device controls the second shutter to open so that the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, thereby exposing the HOE, including: the control device receives first information from a second detection device, and the first information indicates that the intensity change value of the sixth beam of light is within a preset range; the control device controls the second shutter to open so that the third beam of light after expansion and the fifth beam of light after expansion are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

[0166] In one possible design, before the control device controls the opening of the second shutter, the method also includes: the second detection device detects whether the light intensity change value of the sixth beam of light is within the preset range; when the light intensity change value of the sixth beam of light is within the preset range, the second detection device sends the first information to the control device.

[0167] In one possible design, the method further includes: controlling the device to close the first shutter when the diffraction efficiency reaches a first threshold value and / or when the first parameter of the interference fringes reaches a second threshold value; wherein the first parameter includes width, shape or brightness contrast.

[0168] For the beneficial effects of the method shown in FIG9 , please refer to the relevant description of the detection system 300 , which will not be repeated here.

[0169] The control device 306 provided in the embodiment of the present application can be a controller integrated with a processor, or can also be a chip or circuit capable of performing the functions corresponding to the above method, and the chip or circuit can be arranged in a device such as a controller. Furthermore, the detection device provided in the embodiment of the present application can also be implemented in the form of hardware or a combination of hardware and computer software. Whether a certain function is performed in the form of hardware or computer software driving hardware depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the embodiment of the present application.

[0170] It should be noted that HOEs are commonly used in various augmented reality (AR) devices or holographic display devices, such as augmented reality head-up display (AR-HUD) systems or AR glasses. Therefore, the detection system used in the embodiments of the present application tests the performance of HOEs, which helps improve the HOE process and thus optimize the performance of the devices to which the HOEs are applied.

[0171] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0172] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each flow and / or box in the flow chart and / or block diagram, as well as the combination of the flow chart and / or box in the flow chart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more flow charts and / or one or more boxes in the block diagram.

[0173] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0174] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0175] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the scope of protection of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A detection system, characterized in that: The system includes a first spectroscopic element, a first detection device, a linear array photoelectric receiving device and an interference element; The first beam splitting element is used to split the first beam of light from the optical element into a first transmitted light and a first reflected light; The first detection device is used to detect a light intensity change value of the first reflected light, where the light intensity change value of the first reflected light is used to characterize the diffraction efficiency of the optical element; The interference element is used to receive the first transmitted light, obtain and project interference fringes; The linear array photoelectric receiving device is used to obtain image information of the interference fringes, and the image information is used to characterize the refractive index change of the optical element.

2. The system according to claim 1, wherein: The optical element includes a holographic optical element (HOE), and the first beam of light is holographic light.

3. The system according to claim 2, characterized in that The system further includes a first light source, a polarization beam splitting element, a first shutter, a second shutter, and a control device; The first light source is used to output a second beam of light; The polarization beam splitting element is configured to split the second beam of light to obtain a third beam of light and a fourth beam of light when the first shutter is opened; The control device is used to control the second shutter to open, so that the third light beam and the fourth light beam are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

4. The system according to claim 3, characterized in that The control device is further used for: The second shutter is controlled to be closed according to a preset period. When the second shutter is closed, the third beam of light irradiates the HOE to obtain the holographic light.

5. The system according to claim 3, wherein: The system also includes a second light source and a third shutter; The second light source is used to output a seventh beam of light; The control device is further configured to control the third shutter to open, and when the third shutter is opened, the seventh beam of light irradiates the HOE to obtain the holographic light; The seventh beam of light has the same propagation direction as the third beam of light.

6. The system according to any one of claims 3 to 5, characterized in that: The system further includes a second beam splitting element, a first beam expanding element, and a second beam expanding element; The first beam expander is configured to expand the third beam of light to obtain an expanded third beam of light; the second beam splitter is configured to split the fourth beam of light to obtain a fifth beam of light and a sixth beam of light; the second beam expander is configured to expand the fifth beam of light to obtain an expanded fifth beam of light; The third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, and the HOE is exposed, comprising: The third beam of light after expansion and the fifth beam of light after expansion are incident on the HOE when the second shutter is opened, so as to expose the HOE.

7. The system according to claim 6, characterized in that The system further includes a second detection device; The control device is used to control the second shutter to open so that the third light beam and the fourth light beam are incident on the HOE when the second shutter is opened, and the HOE is exposed, specifically for: receiving first information from the second detection device, wherein the first information indicates that a change in the intensity of the sixth light beam is within a preset range; The second shutter is controlled to be opened, so that the third beam of light after expansion and the fifth beam of light after expansion are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

8. The system according to claim 7, characterized in that The second detection device is used to: detecting whether a change in the light intensity of the sixth light beam is within the preset range; When the light intensity change value of the sixth light beam is within the preset range, the first information is sent to the control device.

9. The system according to any one of claims 3 to 8, characterized in that: The control device is further used for: When the diffraction efficiency reaches a first threshold value, and / or when the first parameter of the interference fringes reaches a second threshold value, controlling the first shutter to close; The first parameter includes width, shape or brightness contrast.

10. The system according to any one of claims 3 to 9, characterized in that: When the third beam of light and the fourth beam of light expose the HOE, the third beam of light and the fourth beam of light are incident on different sides of the HOE, or the third beam of light and the fourth beam of light are incident on the same side of the HOE.

11. The system according to any one of claims 6 to 10, characterized in that: The first beam expanding element or the second beam expanding element includes a spatial light filter and a lens.

12. The system according to any one of claims 6 to 10, characterized in that: The first beam expanding element or the second beam expanding element includes a lens and an off-axis reflector.

13. The system according to any one of claims 1 to 12, characterized in that: The linear array photoelectric receiving device is a charge coupled device (CCD) camera or a complementary metal oxide semiconductor (CMOS) camera.

14. A detection method, characterized in that: The method comprises: The first beam splitting element splits the first light beam from the optical element into a first transmitted light and a first reflected light; A first detection device detects a light intensity change value of the first reflected light, where the light intensity change value of the first reflected light is used to characterize the diffraction efficiency of the optical element; The interference element receives the first transmitted light, obtains and projects interference fringes; A linear array photoelectric receiving device acquires image information of the interference fringes, and the image information is used to characterize the refractive index change of the optical element.

15. The method according to claim 14, characterized in that The optical element is a holographic optical element (HOE), and the first beam of light is holographic light.

16. The method according to claim 15, characterized in that The method further comprises: When the first shutter is opened, the polarization beam splitter splits the second beam of light to obtain a third beam of light and a fourth beam of light; wherein the second beam of light is output by the first light source; The control device controls the second shutter to open, so that the third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

17. The method according to claim 16, characterized in that The method further comprises: The control device controls the second shutter to close according to a preset period. When the second shutter is closed, the third beam of light irradiates the HOE to obtain the holographic light.

18. The method according to claim 16, characterized in that The method further comprises: The control device controls the third shutter to open, so that the seventh beam of light illuminates the HOE when the third shutter is opened, thereby obtaining the holographic light; The seventh beam of light is output by the second light source, and the propagation direction of the seventh beam of light is the same as that of the third beam of light.

19. The method according to any one of claims 16 to 18, characterized in that: The method further comprises: A first beam expanding element expands the third beam of light to obtain an expanded third beam of light; The second beam splitter splits the fourth beam of light to obtain a fifth beam of light and a sixth beam of light; The second beam expanding element expands the fifth beam of light to obtain an expanded fifth beam of light; The third beam of light and the fourth beam of light are incident on the HOE when the second shutter is opened, and the HOE is exposed, comprising: The third beam of light after expansion and the fifth beam of light after expansion are incident on the HOE when the second shutter is opened, so as to expose the HOE.

20. The method according to claim 19, characterized in that The control device controls the second shutter to open so that the third light beam and the fourth light beam are incident on the HOE when the second shutter is opened, thereby exposing the HOE, including: The control device receives first information from the second detection device, where the first information indicates that the intensity change value of the sixth light beam is within a preset range; The control device controls the second shutter to open, so that the third beam of light after expansion and the fifth beam of light after expansion are incident on the HOE when the second shutter is opened, thereby exposing the HOE.

21. The method according to claim 20, characterized in that Before the control device controls the second shutter to open, the method further includes: The second detection device detects whether the intensity change value of the sixth light beam is within the preset range; The second detection device sends the first information to the control device when the light intensity change value of the sixth light beam is within the preset range.

22. The method according to any one of claims 16 to 21, characterized in that The method further comprises: The control device controls the first shutter to close when the diffraction efficiency reaches a first threshold value and / or when the first parameter of the interference fringes reaches a second threshold value; The first parameter includes width, shape or brightness contrast.

Images