Integral sphere-based reflective hologram display luminance test system and test method

Abstract

This invention relates to the field of holographic display and optical measurement technology, specifically disclosing a brightness testing system and method for reflective hologram displays based on an integrating sphere. The method uses a single-wavelength laser, spatially filtered and collimated, incident at a specific angle onto a reflective hologram placed within an integrating sphere for reconstruction. The integrating sphere is used to integrate and collect the multi-angle, non-uniform light rays diffracted from the hologram, and a light trap is used to suppress the zero-order reflection background. System calibration is performed using a standard diffuse white plate, and the absolute diffraction efficiency of the hologram is finally calculated. This invention effectively solves the problem that traditional point measurement methods are difficult to accurately obtain the total diffracted light flux of a hologram, and is suitable for the quantitative evaluation of the brightness and efficiency of diffractive optical elements such as reflective holograms and volume holographic gratings.

Description

Technical Field

[0001] This invention belongs to the field of optical measurement and holographic display technology, specifically relating to a method and system for testing the display brightness and diffraction efficiency of diffractive optical elements such as reflective holograms and volume holographic gratings, and in particular, a reflective hologram display brightness testing system and method based on an integrating sphere. Background Technology

[0002] Reflective holograms are widely used in displays, anti-counterfeiting, and optical storage because they can reproduce monochromatic images under white light. One of the core indicators of their display effect is diffraction efficiency, which is the ratio of diffracted light flux to incident light flux. Traditional measurement methods often use point detectors to receive light at a specific angle. However, due to the complex and non-uniform spatial distribution of diffracted light in reflective holograms, single-angle measurements cannot reflect the total diffracted light flux, leading to inaccurate evaluation and poor repeatability.

[0003] An integrating sphere is a commonly used optical flux integrating device that homogenizes incident light after multiple diffuse reflections. The output signal is proportional to the total incident light flux and is independent of the incident light angle and spatial distribution.

[0004] Traditional integrating spheres are mainly used for measuring the brightness and reflectivity of uniformly diffuse or transmissive samples (such as coatings, thin films, and ordinary displays). Holographic displays, however, possess unique technical characteristics, and current technologies are not yet sufficient for their testing. The technical challenges include the drastic change in holographic brightness with the observation angle, and the inability of ordinary integrating spheres' port layout and light collection methods to fully capture the brightness contribution from different viewing angles. Secondly, holograms are based on coherent light imaging, and multiple reflections from the inner wall of the integrating sphere easily introduce coherent interference stray light, leading to brightness measurement errors exceeding 15%. Furthermore, the dynamic range of brightness in holographic displays typically reaches 10... 4 The value is above 1, far exceeding the linear response range of a typical integrating sphere.

[0005] Currently, integrating spheres are mainly used for measuring the total luminous flux of uniformly emitting bodies such as lamps and displays. Their application in measuring optical components with strong backgrounds, weak signals, and angle sensitivity, such as holograms, has not yet been observed. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for testing the brightness of reflective hologram displays based on an integrating sphere. On the one hand, it solves the problem that traditional point measurement methods cannot accurately obtain the total diffraction flux of the hologram across the entire viewing angle, and the measurement results cannot reflect the actual display brightness. On the other hand, it addresses the core pain points of conventional integrating spheres being unsuitable for reflective hologram testing due to poor structural adaptability, large coherent noise interference, and insufficient weak signal detection capability. This enables objective, quantitative, highly repeatable, and high-precision measurement of the brightness and absolute diffraction efficiency of reflective hologram displays.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A brightness testing method for reflective hologram displays based on an integrating sphere is disclosed. The method employs a brightness testing system for reflective hologram displays based on an integrating sphere. The testing system includes a single-wavelength laser source, a spatial light filter, a collimating lens, an integrating sphere, a light trap, a sample holder, and a photodetector. The testing steps include: S1. Fix the reflection hologram sample on the two-dimensional rotating sample holder inside the integrating sphere, and adjust the reconstructed laser output from the single-wavelength laser source so that the reconstructed laser is incident on the reflection hologram sample at a Bragg angle. The specific adjustment process includes: S11, Pre-positioning coarse adjustment: Based on the nominal angle and wavelength data determined when the reflection hologram sample is recorded, the pitch and azimuth angles of the sample are adjusted by the two-dimensional rotating sample holder so that the incident direction of the reconstructed laser coincides with the nominal Bragg incident direction of the reflection hologram sample, and the coarse adjustment limiting structure of the sample holder is locked. S12, Polarization state matching: Adjust the polarization control element in the spatial light filtering and collimation module to make the polarization state of the reconstructed laser consistent with the polarization state when the reflection hologram sample is recorded, and record the initial signal value of the photodetector at this time; S13. Bragg Angle Fine-tuning and Judgment: Based on the pre-positioned angle in step S11, the fine-tuning structure of the high-precision two-dimensional rotating sample holder is used to... The step value is scanned back and forth along the pitch and azimuth directions to adjust the sample angle, and the real-time signal value output by the photodetector is collected simultaneously. When the real-time signal value reaches the global maximum value and the signal value shows a monotonically decreasing trend after deviating from the angle, it is determined that the incident angle of the reconstructed laser is the Bragg angle of the reflected hologram sample, and the fine-tuning limit structure of the sample holder is locked to complete the incident angle adjustment. S2. The integrating sphere is used to collect the multi-angle, non-uniform diffraction light generated by the diffraction of the reflection hologram sample from the reflection hologram sample, and the light trap is used to absorb the zero-order reflected light formed by the direct reflection of the reconstructed laser by the reflection hologram sample. S3. The light signal output by the integrating sphere is measured by the photodetector. The light signal is converted into an electrical signal by the photodetector and transmitted to the data processing unit. The incident light flux of the test optical system is calibrated in conjunction with a standard diffuse reflection white board. The absolute diffraction efficiency of the reflection hologram sample is calculated based on the calibration result and the light signal measured by the photodetector. The reproduction display brightness value of the sample is calculated based on the absolute diffraction efficiency.

[0008] Furthermore, the specific process of calibration using a standard diffuse whiteboard in step S3 is as follows: S31, Given a known reflectance... The standard diffuse whiteboard is fixed to the two-dimensional rotating sample holder through the sample port of the integrating sphere, and the single-wavelength laser source is controlled to output laser light to keep the incident angle of the whiteboard consistent with the Bragg incident angle locked in step S1. S32. Control the single-wavelength laser source to output a reconstructed laser with parameters consistent with those in step S1. After the laser power stabilizes, record the reference signal value output by the photodetector. ; S33. Turn off the single-wavelength laser source, keep the operating status of other components of the system unchanged, and record the dark noise signal value of the photodetector. ; S34, According to the formula The incident luminous flux incident on the standard diffuse white plate was calculated. Complete the system incident light flux calibration.

[0009] Furthermore, the process of calculating the absolute diffraction efficiency and display brightness of the reflection hologram sample in step S3 is as follows: S35. Remove the standard diffuse reflection white plate, fix the reflection hologram sample on the two-dimensional rotating sample holder, maintain the Bragg angle incident state locked in step S1, and record the sample test signal value of the photodetector. ; S36. Using the fine-tuning structure of the high-precision two-dimensional rotating sample holder, rotate the reflective hologram sample until the diffraction signal disappears. At this point, the output signal value of the photodetector drops to within ±5% of the dark noise level. Record the background signal value output by the photodetector. ; S37. According to the formula The net diffraction signal value was calculated. ; S38. According to the formula The absolute diffraction efficiency η of the reflection hologram sample was calculated. S39. According to the formula The reconstructed display brightness value of the reflection hologram sample was calculated. In the formula The brightness conversion coefficient of the integrating sphere system is obtained in advance by calibrating a standard brightness source.

[0010] Furthermore, prior to step S1, the method also includes a reconstructed laser pre-calibration step: placing a matching holographic grating, recorded in the same batch as the reflection hologram sample, on the output light path of the spatial light filtering and collimation module, adjusting the incident angle and output wavelength of the reconstructed laser to make the dispersion shift of the transmitted light less than 0.1 nm, completing the wavelength and angle pre-calibration of the reconstructed laser, and ensuring that the wavelength and incident angle of the reconstructed laser match those of the reflection hologram sample.

[0011] On the other hand, the present invention also provides a brightness testing system for reflective hologram displays based on an integrating sphere. This system is capable of performing the testing process described in the integrated sphere-based brightness testing method for reflective hologram displays. The system includes: A single-wavelength laser used to output reproduced laser light; A spatial light filtering and collimation module, comprising a spatial light filter and a collimating lens arranged sequentially, is used to filter, adjust the polarization state of the reproduced laser output from the single-wavelength laser, and form a uniform collimated laser beam. The integrating sphere assembly includes an integrating sphere body, a two-dimensional rotating sample holder, an optical trap, and a limiting structure. The two-dimensional rotating sample holder is disposed at the sample port within the integrating sphere body and is used to place and adjust the pitch and azimuth angles of the reflected hologram sample in two dimensions. The sample holder is equipped with coarse and fine adjustment limiting structures, and the angle adjustment step accuracy of the fine adjustment structure is not less than [specified value]. The light trap is fixed inside the integrating sphere and located in the direction of propagation of the zero-order reflected light, and is used to absorb the zero-order reflected light. The inner wall of the integrating sphere is coated with a high diffuse reflection coating. A photoelectric detection module, comprising a photodetector connected to the detector port of the integrating sphere body, for receiving optical signals output by the integrating sphere body and converting them into electrical signals; The data processing unit is electrically connected to the photodetector and is used to receive the electrical signal output by the photodetector, perform incident light flux calibration calculation in combination with the known reflectivity of the standard diffuse white board, and calculate the absolute diffraction efficiency and display brightness value of the reflection hologram sample based on the calibration result and the electrical signal.

[0012] Furthermore, the high diffuse reflection coating on the inner wall of the integrating sphere is a barium sulfate coating or a polytetrafluoroethylene coating. The integrating sphere has at least four ports, namely a laser incident port, a sample port, a detector port, and a light trap port. The laser incident port is used to allow the uniform collimated laser beam to enter the integrating sphere. The sample port is used for the placement and fixing of the reflection hologram sample. The detector port is used to install the photodetector. The light trap port is used to fix the light trap. The aperture ratio of the integrating sphere body is no greater than 5%, and the aperture ratio is the ratio of the total area of ​​all openings on the integrating sphere body to the total area of ​​the inner wall of the integrating sphere body. Further, the integrating sphere assembly also includes a baffle plate disposed within the integrating sphere body and located between the sample holder and the detector port, used to block light rays directly emitted from the reflected hologram sample and the first reflected light rays from the inner wall of the integrating sphere body from directly entering the detector port; The single-wavelength laser is a polarization-controllable laser source. The spatial light filtering and collimation module also includes a polarization control element. The polarization control element is disposed between the spatial light filter and the collimating lens and is used to adjust the polarization state of the uniform collimated laser beam so that the polarization state of the uniform collimated laser beam is consistent with the polarization state when the reflection hologram sample is recorded.

[0013] Furthermore, the integrating sphere assembly also includes a rotating scattering plate, which is disposed inside the laser entrance of the integrating sphere body to reduce the interference of laser speckle formed by the uniformly collimated laser beam within the integrating sphere body on the measurement results.

[0014] The photoelectric detection module also includes a signal amplification circuit and an analog-to-digital conversion module. The signal amplification circuit is connected between the photoelectric detector and the analog-to-digital conversion module and is used to amplify the electrical signal output by the photoelectric detector. The analog-to-digital conversion module is electrically connected to the data processing unit and is used to convert the amplified analog electrical signal into a digital signal and transmit it to the data processing unit. The data processing unit has a built-in calibration calculation module and an efficiency calculation module. The calibration calculation module is used to call the known reflectivity parameters of the standard diffuse white plate and calculate the incident light flux by combining the reference signal value and dark noise signal value measured by the photodetector. The efficiency calculation module is used to call the calculation results of the calibration calculation module, combine the sample test signal value and background signal value measured by the photodetector to calculate the absolute diffraction efficiency, and generate a test report.

[0015] Working principle: The diffraction efficiency of a reflective volume hologram satisfies the Bragg diffraction condition. The diffraction efficiency reaches its maximum value only when the incident light angle and wavelength match the parameters used during hologram recording. Beyond the Bragg angle, the diffraction efficiency decreases exponentially and monotonically. This invention achieves quantitative angle adjustment through a high-precision two-dimensional rotating sample holder, using the real-time maximum signal value of the photodetector as the objective criterion for the Bragg angle. This completely avoids errors from subjective adjustments, ensuring the repeatability and accuracy of the test results.

[0016] Absolute diffraction efficiency is the core determining parameter for the brightness of a reflection hologram, and the two are linearly positively correlated. Under the condition of a fixed incident light flux, the higher the absolute diffraction efficiency, the greater the total diffracted light flux in the hologram reconstruction, and the higher the corresponding display brightness. This invention achieves complete collection of diffracted light across all angles using an integrating sphere, accurately measures the absolute diffraction efficiency of the hologram, and then uses a calibrated brightness conversion coefficient to achieve an objective, multi-view quantitative evaluation of the hologram display brightness. This solves the problem that traditional point measurement methods are limited by the observation angle and cannot reflect the actual display brightness of the hologram.

[0017] Beneficial effects: This invention achieves full-angle diffraction light collection through an integrating sphere, overcoming the limitations of traditional point measurement methods and accurately obtaining the total diffraction light flux; secondly, the use of light traps effectively suppresses zero-order reflection background, improving the signal-to-noise ratio; thirdly, combined with standard whiteboard calibration, it achieves quantitative measurement of absolute diffraction efficiency; finally, the provided testing system is suitable for laboratory and industrial testing scenarios, and has high practicality and repeatability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the test system of the present invention; Figure 2 A schematic diagram of the internal optical path and optical trap layout of the integrating sphere; Figure 3 This is a flowchart of the testing method.

[0019] In the figure: 1-Laser, 2-Spatial light filter, 3-Collimating lens, 4-Integrating sphere, 5-Two-dimensional rotating sample holder, 6-Reflection hologram, 7-Light trap, 8-Photodetector, 9-Data processing unit, 10-High diffuse reflection coating, 11-Baffle. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, the testing system of this invention optimizes the baffle layout and port angle of the integrating sphere, and adds a viewing angle compensation module to ensure that holographic reflected light from different angles is collected uniformly. The specific structure is as follows: Figure 1 As shown.

[0022] The testing system provided by this invention includes a laser 1, a spatial light filter 2, a collimating lens 3, an integrating sphere 4, a sample holder 5, a light trap 7, a photodetector 8, and a data processing unit 9. The laser 1 outputs a single-wavelength laser beam, which is filtered by the spatial light filter 2 and collimated by the collimating lens 3 to form a uniform collimated beam, which is incident at a Bragg angle onto a reflected hologram 6 placed on the sample holder 5 inside the integrating sphere 4.

[0023] The inner wall of the integrating sphere 4 is coated with a high diffuse reflectance material such as barium sulfate or polytetrafluoroethylene, and it has four ports: a laser entrance port, a sample port, a detector port, and a light trap port. The light trap 7 is located in the direction of zero-order reflected light and is made of black light-absorbing material. It is used to absorb directly reflected light and prevent it from contaminating the background inside the integrating sphere.

[0024] The measurement process is as follows: System dark noise measurement: The dark field photoelectric signal within the integrating sphere 4 is acquired by the photodetector 8 and recorded as the dark noise signal value by the data processing unit 9. .

[0025] Incident light calibration: Place a standard diffuse white plate (reflectance) at the sample port. (As known), turn on the laser, use photodetector 8 to sense the homogenized light signal reflected by a standard diffuse white plate, and record it as the reference signal value. Calculate the incident luminous flux: .

[0026] Holographic diffraction signal measurement: Replace with a holographic sample and adjust to the Bragg angle. Photodetector 8 monitors the integrated diffraction signal generated by the hologram in real time and converts it into the corresponding electrical signal value. .

[0027] Background signal measurement: Slightly rotate the sample or change the wavelength until diffraction disappears. In the state where diffraction disappears, extract the residual background scattering signal of the system using photodetector 8. .

[0028] Calculate the net diffraction signal: (or ).

[0029] Calculate the absolute diffraction efficiency:

[0030] To further improve measurement accuracy, a rotating scattering plate can be added inside the integrating sphere to reduce the influence of laser speckle, and a polarization controller can be used to keep the laser polarization state consistent with that recorded in the hologram.

[0031] This invention is not only applicable to reflective holograms, but can also be extended to the optical efficiency testing of transmission holograms, volume holographic gratings, diffractive optical elements, etc., providing a reliable and integrated measurement method for the quality evaluation of holographic display elements.

[0032] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of testing the luminance of a reflective hologram based on an integrating sphere, characterized in that, The method employs a reflective hologram display brightness testing system based on an integrating sphere. The testing system includes a single-wavelength laser source, a spatial light filter, a collimating lens, an integrating sphere, a light trap, a sample holder, and a photodetector. The testing steps include: S1. Fix the reflection hologram sample on the two-dimensional rotating sample holder inside the integrating sphere, and adjust the reconstructed laser output from the single-wavelength laser source so that the reconstructed laser is incident on the reflection hologram sample at a Bragg angle. The specific adjustment process includes: S11, Pre-positioning coarse adjustment: Based on the nominal angle and wavelength data determined when the reflection hologram sample is recorded, the pitch and azimuth angles of the sample are adjusted by the two-dimensional rotating sample holder so that the incident direction of the reconstructed laser coincides with the nominal Bragg incident direction of the reflection hologram sample, and the coarse adjustment limiting structure of the sample holder is locked. S12, Polarization state matching: Adjust the polarization control element in the spatial light filtering and collimation module to make the polarization state of the reconstructed laser consistent with the polarization state when the reflection hologram sample is recorded, and record the initial signal value of the photodetector at this time; S13. Bragg Angle Fine-tuning and Judgment: Based on the pre-positioned angle in step S11, the fine-tuning structure of the high-precision two-dimensional rotating sample holder is used to... The step value is scanned back and forth along the pitch and azimuth directions to adjust the sample angle, and the real-time signal value output by the photodetector is collected simultaneously. When the real-time signal value reaches the global maximum value and the signal value shows a monotonically decreasing trend after deviating from the angle, it is determined that the incident angle of the reconstructed laser is the Bragg angle of the reflected hologram sample, and the fine-tuning limit structure of the sample holder is locked to complete the incident angle adjustment. S2. The integrating sphere is used to collect the multi-angle, non-uniform diffraction light generated by the diffraction of the reflection hologram sample from the reflection hologram sample, and the light trap is used to absorb the zero-order reflected light formed by the direct reflection of the reconstructed laser by the reflection hologram sample. S3. The light signal output by the integrating sphere is measured by the photodetector. The light signal is converted into an electrical signal by the photodetector and transmitted to the data processing unit. The incident light flux of the test optical system is calibrated in conjunction with a standard diffuse reflection white board. The absolute diffraction efficiency of the reflection hologram sample is calculated based on the calibration result and the light signal measured by the photodetector. The reproduction display brightness value of the sample is calculated based on the absolute diffraction efficiency.

2. The brightness testing method for reflective hologram displays based on an integrating sphere according to claim 1, characterized in that, The specific process of calibration using a standard diffuse whiteboard in step S3 is as follows: S31, Given a known reflectance... The standard diffuse whiteboard is fixed to the two-dimensional rotating sample holder through the sample port of the integrating sphere, and the single-wavelength laser source is controlled to output laser light to keep the incident angle of the whiteboard consistent with the Bragg incident angle locked in step S1. S32. Control the single-wavelength laser source to output a reconstructed laser with parameters consistent with those in step S1. After the laser power stabilizes, record the reference signal value output by the photodetector. ; S33. Turn off the single-wavelength laser source, keep the operating status of other components of the system unchanged, and record the dark noise signal value of the photodetector. ; S34, According to the formula The incident luminous flux incident on the standard diffuse white plate was calculated. Complete the system incident light flux calibration.

3. The brightness testing method for reflective hologram displays based on an integrating sphere according to claim 1, characterized in that, The process of calculating the absolute diffraction efficiency and display brightness of the reflection hologram sample in step S3 is as follows: S35. Remove the standard diffuse reflection white plate, fix the reflection hologram sample on the two-dimensional rotating sample holder, maintain the Bragg angle incident state locked in step S1, and record the sample test signal value of the photodetector. ; S36. Using the fine-tuning structure of the high-precision two-dimensional rotating sample holder, rotate the reflective hologram sample until the diffraction signal disappears. At this point, the output signal value of the photodetector drops to within ±5% of the dark noise level. Record the background signal value output by the photodetector. ; S37. According to the formula The net diffraction signal value was calculated. ; S38. According to the formula The absolute diffraction efficiency η of the reflection hologram sample was calculated. S39. According to the formula The reconstructed display brightness value of the reflection hologram sample was calculated. In the formula The brightness conversion coefficient of the integrating sphere system is obtained in advance by calibrating a standard brightness source.

4. The brightness testing method for reflective hologram displays based on an integrating sphere according to claim 1, characterized in that, Before step S1, a reconstructed laser pre-calibration step is also included: placing the matching holographic grating recorded in the same batch as the reflection hologram sample in the output light path of the spatial light filtering and collimation module, adjusting the incident angle and output wavelength of the reconstructed laser to make the dispersion shift of the transmitted light less than 0.1 nm, completing the wavelength and angle pre-calibration of the reconstructed laser, and ensuring that the wavelength and incident angle of the reconstructed laser match those of the reflection hologram sample.

5. A brightness testing system for reflective hologram displays based on an integrating sphere, characterized in that, The system is capable of performing the testing process of the reflective hologram display brightness testing method based on an integrating sphere as described in any one of claims 1-4, wherein the system comprises: A single-wavelength laser used to output reproduced laser light; A spatial light filtering and collimation module, comprising a spatial light filter and a collimating lens arranged sequentially, is used to filter, adjust the polarization state of the reproduced laser output from the single-wavelength laser, and form a uniform collimated laser beam. The integrating sphere assembly includes an integrating sphere body, a two-dimensional rotating sample holder, an optical trap, and a limiting structure. The two-dimensional rotating sample holder is disposed at the sample port within the integrating sphere body and is used to place and adjust the pitch and azimuth angles of the reflected hologram sample in two dimensions. The sample holder is equipped with coarse and fine adjustment limiting structures, and the angle adjustment step accuracy of the fine adjustment structure is not less than [specified value]. The light trap is fixed inside the integrating sphere and located in the direction of propagation of the zero-order reflected light, and is used to absorb the zero-order reflected light. The inner wall of the integrating sphere is coated with a high diffuse reflection coating. A photoelectric detection module, comprising a photodetector connected to the detector port of the integrating sphere body, for receiving optical signals output by the integrating sphere body and converting them into electrical signals; The data processing unit is electrically connected to the photodetector and is used to receive the electrical signal output by the photodetector, perform incident light flux calibration calculation in combination with the known reflectivity of the standard diffuse white board, and calculate the absolute diffraction efficiency and display brightness value of the reflection hologram sample based on the calibration result and the electrical signal.

6. The reflective hologram display brightness testing system based on an integrating sphere according to claim 5, characterized in that, The high diffuse reflection coating on the inner wall of the integrating sphere is a barium sulfate coating or a polytetrafluoroethylene coating. The integrating sphere has at least four ports, namely a laser incident port, a sample port, a detector port, and a light trap port. The laser incident port is used to allow the uniform collimated laser beam to enter the integrating sphere. The sample port is used for the placement and fixing of the reflection hologram sample. The detector port is used to install the photodetector. The light trap port is used to fix the light trap. The aperture ratio of the integrating sphere body is no greater than 5%, and the aperture ratio is the ratio of the total area of ​​all openings on the integrating sphere body to the total area of ​​the inner wall of the integrating sphere body.

7. The reflective hologram display brightness testing system based on an integrating sphere according to claim 5, characterized in that, The integrating sphere assembly also includes a baffle disposed within the integrating sphere body and located between the sample holder and the detector port, for blocking the light emitted directly from the reflected hologram sample and the light reflected for the first time from the inner wall of the integrating sphere body from directly entering the detector port.

8. The reflective hologram display brightness testing system based on an integrating sphere according to claim 5, characterized in that, The single-wavelength laser is a polarization-controllable laser source. The spatial light filtering and collimation module also includes a polarization control element. The polarization control element is disposed between the spatial light filter and the collimating lens and is used to adjust the polarization state of the uniform collimated laser beam so that the polarization state of the uniform collimated laser beam is consistent with the polarization state when the reflection hologram sample is recorded.

9. The reflective hologram display brightness testing system based on an integrating sphere according to claim 5, characterized in that, The integrating sphere assembly also includes a rotating scattering plate, which is disposed inside the laser entrance of the integrating sphere body to reduce the interference of laser speckle formed by the uniformly collimated laser beam within the integrating sphere body on the measurement results.

10. The reflective hologram display brightness testing system based on an integrating sphere according to claim 5, characterized in that, The photoelectric detection module also includes a signal amplification circuit and an analog-to-digital conversion module. The signal amplification circuit is connected between the photoelectric detector and the analog-to-digital conversion module and is used to amplify the electrical signal output by the photoelectric detector. The analog-to-digital conversion module is electrically connected to the data processing unit and is used to convert the amplified analog electrical signal into a digital signal and transmit it to the data processing unit. The data processing unit has a built-in calibration calculation module and an efficiency calculation module. The calibration calculation module is used to call the known reflectivity parameters of the standard diffuse white plate and calculate the incident light flux by combining the reference signal value and dark noise signal value measured by the photodetector. The efficiency calculation module is used to call the calculation results of the calibration calculation module, combine the sample test signal value and background signal value measured by the photodetector to calculate the absolute diffraction efficiency, and generate a test report.

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