A stray light measurement device

Abstract

This invention provides a stray light measurement device, aiming to solve the problem that existing devices cannot accurately measure stray light. It can accurately measure the stray light characteristics of different samples, improving measurement efficiency and compatibility. The device includes an integrating sphere light source, a first photodetector, and a stage. The integrating sphere light source includes an integrating sphere and an illumination source. The wall of the integrating sphere has an exit port and a recess, and the line connecting the center of the recess and the center of the exit port passes through the center of the integrating sphere. The stage includes a test position and a first switching mechanism. The test position is located on the measurement optical path between the exit port and the first photodetector, closer to the exit port of the integrating sphere. The first switching mechanism is used to switch the sample or standard scattering plate to the test position. The light beam emitted by the integrating sphere light source enters the test position through the exit port. The first photodetector receives and measures the light beam transmitted through the sample or standard scattering plate at the test position.

Description

Technical Field

[0001] This utility model relates to the field of optical radiation measurement, specifically to a stray light measurement device. Background Technology

[0002] In the performance evaluation of optical systems, the measurement of stray light is a crucial aspect. Stray light refers to unexpected light rays generated in an optical system due to factors such as surface reflection of components, internal scattering, or system structure, which are unrelated to the imaging beam or the desired optical path. This type of light can reduce image contrast, introduce measurement errors, and adversely affect the imaging quality and measurement accuracy of the optical system.

[0003] For display devices such as AR devices, measuring the stray light at the front is particularly important, as it directly affects the display effect and user experience. Currently, the industry commonly uses a combination of integrating sphere light sources and photoelectric detection devices such as luminance meters to measure the stray light at the front of display devices.

[0004] In conventional stray light measurement procedures, the sample under test (DUT) is typically removed from the integrating sphere's exit port, and the photodetector is then used to measure the light in the air. However, this method has significant drawbacks. When the DUT is placed at the integrating sphere's exit port, it interacts with the light beam emitted by the integrating sphere, and the light scattering state within the integrating sphere is influenced by the presence of the DUT. When the DUT is removed and measurement is performed solely through air, the light scattering state within the integrating sphere is entirely different. Air, as a medium without a physical optical interface, cannot simulate the influence of the DUT on the light field within the integrating sphere. Therefore, the results obtained through air measurement do not represent the true background scattering photometric value when actually measuring the DUT, leading to a deviation between the baseline measurement and actual requirements. This affects the accuracy and reliability of stray light measurement, making it difficult to meet the stray light evaluation requirements of high-precision optical systems. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention provides a stray light measuring device, aiming to solve the problem that existing measuring devices cannot accurately measure stray light.

[0006] To achieve the above technical objectives, the technical solution adopted by this utility model is as follows:

[0007] This invention provides a stray light measurement device, comprising an integrating sphere light source, a first photodetector, and a stage for placing a sample and a standard scattering plate. The integrating sphere light source includes an integrating sphere and an illumination source. The wall of the integrating sphere has an exit port and a recess, and the line connecting the center of the recess and the center of the exit port passes through the center of the integrating sphere. The stage includes a test position and a first switching mechanism. The test position is located on the measurement optical path between the exit port and the first photodetector, closer to the exit port of the integrating sphere. The first switching mechanism is used to switch the sample or standard scattering plate to the test position. The light beam emitted by the integrating sphere light source enters the test position through the exit port. The first photodetector is used to receive and measure the light beam transmitted through the sample or standard scattering plate at the test position.

[0008] In the above technical solution, an integrating sphere light source provides a uniform and stable light source. The stage integrates a test position and a first switching mechanism, enabling automatic, rapid, and accurate switching between the sample under test and the standard diffuser plate at the test position. Measurements are performed on both the standard diffuser plate and the sample under test at the same test position, ensuring high consistency in key measurement conditions such as the incident angle of the light source, the spot size, and the receiving position and angle of the first photodetector. This effectively eliminates systematic errors caused by position changes, making the measurement results of the sample under test and the standard diffuser plate comparable, thereby improving the accuracy and reliability of stray light measurement. The first photodetector includes, but is not limited to, a spectroradiometer, a photometer, an illuminance meter, an imaging luminance meter, or a luminance meter.

[0009] As a technical solution, it also includes a second switching mechanism, which is set at the light trap; a switchable light trap or white board is set in the outgoing light path of the light trap, and the white board or light trap is switched to the outgoing light path of the light trap by the second switching mechanism. The white board is coated with a diffuse reflection coating with a reflectivity similar to that of the integrating sphere wall coating, and the light trap is a black board or light-absorbing trap plate coated with light-absorbing material or a black light-absorbing barrel. In a specific embodiment, the first photodetector is a luminance meter, and the specific measurement process includes: (1) setting a white board at the light trap, turning on the integrating sphere light source, preheating the light source and luminance meter to a stable state, cutting the standard scattering plate into the test position, and measuring the luminance L by the luminance meter. v1 (2) Set a white plate in the light trap, switch to the standard scattering plate, cut the sample to be tested into the test position, and measure the brightness L with a luminance meter. v2 (3) Set up a light trap at the light trap, switch the test position to a standard scattering plate, and measure the brightness L with a luminance meter. v3 (4) A light trap is set at the light trap, the test position is the sample being tested, and the brightness L is measured by the luminance meter. v4 Front stray light H de / 0 The calculation method is as follows: The core characteristic of front stray light (Hde / O) is its superposition interference with the sample's own scattering signal, which is difficult to distinguish accurately using traditional air measurement methods. In this scheme, a white plate is coated with a diffuse reflection coating similar to the wall of the integrating sphere, which can simulate the stray light environment generated by the reflection from the sphere wall; the light trap completely absorbs the stray light through light-absorbing materials, eliminating reflection interference. Combined with the switching measurement of the standard scattering plate (reference) and the sample under test, four brightness values ​​(L) are obtained. v1 -L v4 The comparative calculation directly isolates the coupling effect of the sample's inherent scattering characteristics and front stray light, enabling quantitative characterization of front stray light and avoiding measurement biases inherent in traditional methods. During measurement, factors such as light source stability, photodetector drift, and ambient light fluctuations can easily introduce systematic errors. This scheme employs a "same source, same path" design, ensuring that all four measurements share the same integrating sphere light source, the same optical path, and the same detector, and that the entire process is completed after the light source and detector have preheated and stabilized. This design allows systematic errors to be naturally canceled out in the ratio calculation, significantly reducing the impact of external interference on the results and ensuring the repeatability and accuracy of the stray light calculation results.

[0010] As a technical solution, the first switching mechanism includes a moving guide rail, the extension direction of which is perpendicular to the measurement optical path direction; the sample to be tested and the standard scattering plate are disposed on the sliding seat of the moving guide rail, and the sliding seat is moved by a lead screw mechanism or belt mechanism to switch the sample to be tested or the standard scattering plate to the test position.

[0011] As a technical solution, the first switching mechanism includes a turntable, the rotation axis of which is parallel to the central axis of the light outlet; the turntable has at least two sample positions, in which the sample to be tested and a standard diffuser are placed; by rotating the turntable, each sample position can be switched into the measurement optical path of the test position, thereby realizing the switching of the sample to be tested or the standard diffuser. In this technical solution, the rotation axis of the turntable is parallel to the optical path, ensuring that the sample to be tested / standard diffuser always maintains a perpendicular relationship with the optical axis when switching, avoiding tilting errors; by switching the sample position with the sample to be tested or the standard diffuser into the test position, the illumination conditions and detector receiving angle are completely consistent, eliminating system errors; the multi-sample position design supports the simultaneous loading of multiple samples to be tested, which can meet the needs of batch testing or multi-parameter calibration.

[0012] As one technical solution, the second switching mechanism includes a turntable with two or more holes, one of which is fitted with a white plate and the other is empty. By rotating the turntable, the white plate or the empty hole is switched to the outgoing light path of the light trap. Alternatively, the second switching mechanism includes a movable baffle, with the side of the baffle facing the integrating sphere being a white plate (coated with a diffuse reflection coating with a reflectivity similar to the coating on the wall of the integrating sphere). When the baffle is removed, the outgoing light from the light trap enters the light trap (black light-absorbing barrel). Alternatively, the second switching mechanism is a hinged flip structure, where the white plate is connected to the wall of the integrating sphere by a hinge, and the white plate is flipped to cut into or out of the outgoing light path of the light trap.

[0013] As a technical solution, a second photodetector is also included. The wall of the integrating sphere is also provided with a monitoring port. The second photodetector is set inside the monitoring port to monitor the illuminance, irradiance, or luminance inside the integrating sphere. The second photodetector is a spectroradiometer, illuminometer, or photometer. The specific stray light measurement process includes: (1) setting a white plate in the light trap, turning on the integrating sphere light source, preheating the light source, the first photodetector, and the second photodetector to a stable state, cutting the standard scattering plate into the test position, and measuring the luminance L with the first photodetector. v1 (2) Set a white plate in the light trap, switch the standard scattering plate, cut the sample to be tested into the test position, and measure the brightness L with the first photodetector. v2 (2) The second photodetector measures the illuminance m2; (3) The light trap is set at the light trap, the test position is switched to the standard scattering plate, and the first photodetector measures the brightness L. v3 The second photodetector measures the illuminance m3; (4) A light trap is set in the light trap, the test position is the sample to be tested, and the first photodetector measures the brightness L. v4 The second photodetector measures the illuminance in m4. Front stray light H de / 0 The calculation method is as follows By monitoring the internal optical field characteristics of the integrating sphere in real time, dynamic calibration and error compensation of the measurement device can be achieved, which can effectively eliminate the influence of light source fluctuations on the measurement results and significantly improve the accuracy and stability of stray light measurement.

[0014] As a technical solution, the illumination source is disposed inside the integrating sphere, and a baffle is included to prevent the emitted light from the illumination source from directly illuminating the light outlet; or the wall of the integrating sphere is also provided with a light inlet, at which the illumination source is installed. Furthermore, an aperture is also provided inside the integrating sphere to prevent the emitted light from the illumination source from directly illuminating the surface of the sample being tested, ensuring that the sample being tested is under diffused illumination conditions.

[0015] As a technical solution, the lighting source is a dimmable combination of two or more colors of LED lights and / or OLED lights. Different colored test samples exhibit selective scattering or absorption characteristics for specific wavelengths of light, making it difficult for a single wavelength light source to fully reflect their stray light behavior. Multi-color LED / OLED combined light sources can cover the visible light band (and even extend to the ultraviolet or near-infrared). By adjusting the luminous intensity, color temperature, and spectral power distribution of the light source, the lighting environment of actual application scenarios can be simulated, making the stray light measurement results closer to real-world usage conditions and enhancing the engineering reference value of the data.

[0016] As a technical solution, the cone angle formed by the opening edge of the light trap and the center of the light outlet is 8°±0.5°.

[0017] The beneficial effects of this utility model are as follows: This utility model provides a stray light measurement device. By utilizing the switching design of the first switching mechanism, it can accurately measure the stray light characteristics of different samples, thereby improving measurement efficiency and compatibility. With the help of dual detectors and adjustable light sources, it effectively reduces system errors and enhances the reliability of results. This device is widely adaptable to multiple samples and complex scenarios, providing comprehensive technical support for optical detection. Attached Figure Description

[0018] Appendix Figure 1 This is a schematic diagram of a stray light measurement device according to Example 1.

[0019] Appendix Figure 2 This is a schematic diagram of the first switching mechanism in Example 1.

[0020] Appendix Figure 3 This is a schematic diagram of a stray light measurement device according to Example 2.

[0021] Appendix Figure 4 This is a schematic diagram of the structure of the first switching mechanism in Embodiment 2.

[0022] The attached diagram shows: 1-integrating sphere light source, 2-first photodetector, 3-stage, 4-light trap, 5-light outlet, 6-test position, 7-sample under test, 8-standard scattering plate, 9-first switching mechanism, 10-second switching mechanism, 11-second photodetector, 12-light trap, 13-white board. Detailed Implementation

[0023] Example 1

[0024] This embodiment discloses a stray light measurement device, such as... Figure 1As shown, the system includes an integrating sphere light source 1, a first photodetector 2, a second photodetector 11, and a stage 3 for placing the sample 7 and the standard diffuser 8. The integrating sphere light source 1 includes an integrating sphere and an illumination source, the illumination source being disposed within the integrating sphere. It also includes a baffle to prevent the emitted light from the illumination source from directly illuminating the light exit port 5. The illumination source is a dimmable LED light source composed of two or more colors. The wall of the integrating sphere also has a light exit port 5 and a light trap 4, the line connecting the center of the light trap 4 and the center of the light exit port 5 passing through the center of the integrating sphere. The stage 3 includes a test position 6 and a first switching mechanism 9. The test position 6 is located on the measurement optical path between the light exit port 5 and the first photodetector 2, closer to the light exit port 5 of the integrating sphere. The first switching mechanism 9 includes a moving guide rail, the extension direction of which is perpendicular to the measurement optical path direction. The sample 7 and the standard diffuser 8 are disposed on a sliding seat of the moving guide rail. The sample 7 or the standard diffuser 8 is switched to the test position 6 by moving the sliding seat. Figure 2 As shown. It also includes a second switching mechanism, which is a hinged flip structure. The white plate 13 is connected to the integrating sphere wall via a hinge. The white plate 13 cuts into or out of the light path of the light trap by flipping. The outside of the light trap is a black light-absorbing barrel. The integrating sphere wall also has a monitoring port, and the second photodetector 11 is installed inside the monitoring port to monitor the illuminance or irradiance inside the integrating sphere. The first photodetector 2 is an imaging luminance meter. The second photodetector 2 is an illuminance meter. During measurement, the light beam emitted by the integrating sphere light source 1 enters the test position 6 through the light exit port 5. The first photodetector 2 is used to receive and measure the light beam transmitted through the sample 7 or standard scattering plate 8 at the test position 6.

[0025] The specific stray light measurement process includes: 1. Setting up a white plate at the light trap, turning on the integrating sphere light source, preheating the light source, the first photodetector, and the second photodetector to a stable state, inserting the standard scattering plate into the test position, and measuring the brightness L with the first photodetector. v1 The second photodetector measures the illuminance m1; a white board is set at the light trap, the standard scattering plate is switched, the sample to be tested is placed in the test position, and the first photodetector measures the brightness L. v2 The second photodetector measures the illuminance (m²); the third light trap is set at the light recess, the test position is switched to a standard scattering plate, and the first photodetector measures the brightness (L). v3 The second photodetector measures the illuminance (m³); a light trap is set at the light recess, with the sample being tested at the test position, and the first photodetector measures the brightness (L). v4 The second photodetector measures the illuminance in m4. Front stray light H de / 0 The calculation method is as follows By monitoring the internal optical field characteristics of the integrating sphere in real time, dynamic calibration and error compensation of the measurement device can be achieved, which can effectively eliminate the influence of light source fluctuations on the measurement results and significantly improve the accuracy and stability of stray light measurement.

[0026] Example 2

[0027] This embodiment discloses a stray light measurement device, such as... Figure 3 As shown, the system includes an integrating sphere light source 1, a first photodetector 2, a second photodetector 11, and a stage 3 for placing the sample 7 and a standard scattering plate 8. The integrating sphere light source 1 includes an integrating sphere and an illumination source. The wall of the integrating sphere has a light inlet, and an illumination source is installed at the light inlet. The illumination source is a dimmable combination of two or more colors of LED lights and / or OLED lights. The integrating sphere wall is also provided with a light exit port 5 and a light trap 4. The line connecting the center of the light trap 4 and the center of the light exit port 5 passes through the center of the integrating sphere. The stage 3 includes a test position 6 and a first switching mechanism 9. The test position 6 is located on the measurement optical path between the light exit port 5 and the first photodetector 2, closer to the light exit port 5 of the integrating sphere. The first switching mechanism 9 includes a turntable, the rotation axis of which is parallel to the central axis of the light exit port 5. The turntable has three sample positions, and the sample to be tested 7 and the standard scattering plate 8 are placed in the sample positions. By rotating the turntable, each sample position can be switched into the measurement optical path of the test position 6, thereby realizing the switching between the sample to be tested 7 and the standard scattering plate 8. Figure 4 As shown. It also includes a second switching mechanism 10, which includes a movable baffle disposed at the light trap 4; the side of the baffle facing the integrating sphere is a white plate 13. When the baffle is removed, the emitted light from the light trap 4 enters the light trap 12. The integrating sphere wall is also provided with a monitoring port, and the second photodetector 11 is disposed in the monitoring port for monitoring the illuminance or radiance within the integrating sphere. The first photodetector 2 is a luminance meter. The second photodetector 2 is an illuminance meter. The cone angle formed by the opening edge of the light trap 4 and the center of the light exit port 5 is 8°±0.5°. During measurement, the light beam emitted by the integrating sphere light source 1 enters the test position 6 through the light exit port 5. The first photodetector 2 is used to receive and measure the light beam transmitted through the sample 7 or standard scattering plate 8 at the test position 6.

[0028] The specific stray light measurement process includes: 1. Setting up a white plate at the light trap, turning on the integrating sphere light source, preheating the light source, the first photodetector, and the second photodetector to a stable state, inserting the standard scattering plate into the test position, and measuring the brightness L with the first photodetector. v1 The second photodetector measures the illuminance m1; a white board is set at the light trap, the standard scattering plate is switched, the sample to be tested is placed in the test position, and the first photodetector measures the brightness L. v2The second photodetector measures the illuminance (m²); the third light trap is set at the light recess, the test position is switched to a standard scattering plate, and the first photodetector measures the brightness (L). v3 The second photodetector measures the illuminance (m³); a light trap is set at the light recess, with the sample being tested at the test position, and the first photodetector measures the brightness (L). v4 The second photodetector measures the illuminance in m4. Front stray light H de / 0 The calculation method is as follows By monitoring the internal optical field characteristics of the integrating sphere in real time, dynamic calibration and error compensation of the measurement device can be achieved, which can effectively eliminate the influence of light source fluctuations on the measurement results and significantly improve the accuracy and stability of stray light measurement.

[0029] The specific embodiments of this utility model have been described above with reference to the accompanying drawings. However, those skilled in the art should understand that the above embodiments are for illustrative purposes only and are not intended to limit the scope of this utility model. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this utility model. The scope of protection of this utility model is defined by the appended claims.

Claims

1. A stray light measuring device, characterized in that The system includes an integrating sphere light source (1), a first photodetector (2), and a stage (3) for placing the sample (7) and the standard scattering plate (8). The integrating sphere light source (1) includes an integrating sphere and an illumination source. The wall of the integrating sphere is provided with an exit port (5) and a light trap (4). The line connecting the center of the light trap (4) and the center of the exit port (5) passes through the center of the integrating sphere. The stage (3) includes a test position (6) and a first switching mechanism (9). The test position (6) is located on the measurement optical path between the exit port (5) and the first photodetector (2), close to the exit port (5) of the integrating sphere. The first switching mechanism (9) is used to switch the sample (7) or the standard scattering plate (8) to the test position (6). The light beam emitted by the integrating sphere light source (1) is incident on the test position (6) through the exit port (5). The first photodetector (2) is used to receive and measure the light beam transmitted through the sample (7) or the standard scattering plate (8) on the test position (6).

2. A stray light measuring apparatus according to claim 1, characterised in that, The first switching mechanism (9) includes a moving guide rail, the extension direction of which is perpendicular to the measurement optical path direction; the sample to be tested (7) and the standard scattering plate (8) are set on the sliding seat of the moving guide rail, and the sample to be tested (7) or the standard scattering plate (8) is switched to the test position (6) by moving the sliding seat.

3. A stray light measuring apparatus according to claim 1, characterised in that The first switching mechanism (9) includes a turntable, the rotation axis of which is parallel to the central axis of the light outlet (5); the turntable is provided with at least two sample positions, and the sample to be tested (7) and the standard scattering plate (8) are set in the sample positions; by rotating the turntable, each sample position can be switched into the measurement optical path of the test position (6), thereby realizing the switching of the sample to be tested (7) or the standard scattering plate (8).

4. The stray light measuring apparatus of claim 1, wherein It also includes a second switching mechanism (10), which is disposed in the light trap (4); the light trap (4) is provided with a switchable light trap or whiteboard in the outgoing light path, and the whiteboard (13) or light trap (12) is switched to the outgoing light path of the light trap (4) by the second switching mechanism (10).

5. A stray light measuring apparatus according to claim 4, characterised in that, The second switching mechanism (10) includes a turntable with two or more holes, one of which is equipped with a white plate and the other is empty. By rotating the turntable, the white plate or the empty hole is switched to the light path of the light trap (4). Alternatively, the second switching mechanism (10) includes a movable baffle, with the side of the baffle facing the integrating sphere being the white plate (13). When the baffle is removed, the light emitted from the light trap (4) enters the light trap (12). Alternatively, the second switching mechanism (10) is a hinged flip structure, in which the white plate is connected to the wall of the integrating sphere by a hinge, and the white plate is flipped into or out of the light path of the light trap (4).

6. The stray light measuring apparatus of claim 1, wherein It also includes a second photodetector (11), and the wall of the integrating sphere is provided with a monitoring port. The second photodetector (11) is set in the monitoring port and is used to monitor the illuminance or irradiance inside the integrating sphere.

7. The stray light measuring apparatus of claim 1, wherein The lighting source is located inside the integrating sphere and includes a baffle to prevent the emitted light from the lighting source from directly irradiating the light outlet (5); or the wall of the integrating sphere is also provided with a light inlet, and a lighting source is installed at the light inlet.

8. The stray light measuring apparatus of claim 1, wherein The lighting source is a dimmable combination of LED lights and / or OLED lights of two or more colors.

9. A stray light measuring device according to claim 1, characterized in that, The first photodetector (2) is a spectroradiometer, photometer, illuminometer, or imaging luminance meter.

10. The stray light measuring apparatus of claim 1, wherein The cone angle formed by the opening edge of the light trap (4) and the center of the light outlet (5) is 8°±0.5°.

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