A method and system for detecting the relative angle of an optical composite film

Abstract

The embodiment of the application provides a kind of optical composite film relative angle of detection method and detection system.The optical composite film relative angle of detection method is applied to the detection system of optical composite film relative angle, and detection system includes: light source component and detection component, optical composite film includes first film layer and second film layer, in the case where optical composite film is rotated and arranged between light source component and detection component, first film layer is arranged relative to second film layer close to light source component;Control linearly polarized light of multiple fields of view to be projected to detection component through optical composite film;Obtain the straight edge angle of optical composite film;According to the straight edge angle and the power data measured by detection component, the optical axis angle of first film layer is obtained;According to the optical parameter measured by detection component, the optical axis angle of second film layer is obtained;According to the optical axis angle of first film layer and the optical axis angle of second film layer, the optical composite film relative angle is obtained.

Description

Technical Field

[0001] This application relates to the field of optical composite film detection technology, and more specifically, to a method and system for detecting the relative angle of optical composite films. Background Technology

[0002] Currently, in the field of VR folded optical paths (Pancake), combining two or more optical films is a common bonding method. For example, the composite bonding method of reflective polarizing film and phase retardation film is a frequently used bonding scheme. However, even slight differences in the relative angle between the transmission axis of the reflective polarizing film and the fast or slow axis of the phase retardation film can significantly affect the imaging effect. Therefore, detecting the relative angle between two or more optical composite films is essential.

[0003] In existing technologies, there are roughly two methods for detecting the relative angle of optical composite films. The first method is to use a polarimeter to detect the relative angle of the optical composite film, but the cost of using a polarimeter is relatively high. The second method is to use a destructive film-peeling detection scheme. This detection scheme is suitable for random inspection after lens film application and film calibration during the R&D stage, but it cannot be applied to mass production on the production line.

[0004] Therefore, this application provides a testing solution that reduces testing costs and eliminates the need for film removal. Summary of the Invention

[0005] The purpose of this application is to provide a new technical solution for a method and system for detecting the relative angle of optical composite films.

[0006] In a first aspect, this application provides a method for detecting the relative angle of an optical composite film. A detection system for detecting the relative angle of an optical composite film is also provided. The detection system includes a light source assembly and a detection assembly, with the optical composite film to be tested positioned between the light source assembly and the detection assembly. The optical composite film includes a first film layer and a second film layer, wherein the first film layer selectively allows polarized light to pass through, and the second film layer converts the polarization state of the polarized light.

[0007] When the optical composite film is rotatably disposed between the light source assembly and the detection assembly, the first film layer is disposed closer to the light source assembly relative to the second film layer;

[0008] The detection method includes:

[0009] Linearly polarized light with multiple fields of view is projected onto the detection component through the optical composite film;

[0010] Obtain the straight edge angle of the optical composite film, wherein the straight edge angle is the angle between the straight edge of the optical composite film and the reference line, and the reference line is the vertical coordinate axis in the visual camera coordinate system;

[0011] The optical axis angle of the first film layer is obtained based on the straight edge angle and the power data measured by the detection component.

[0012] The optical axis angle of the second film is obtained based on the optical parameters measured by the detection component.

[0013] The relative angle between the optical composite films is obtained based on the optical axis angles of the first film layer and the second film layer.

[0014] Optionally, obtaining the optical axis angle of the first film layer based on the power data measured by the detection component and the straight edge angle of the optical composite film specifically includes:

[0015] A mathematical model is established by fitting the power data measured by the detection component and the straight edge angle of the optical composite film. The straight edge angle of the optical composite film corresponding to the minimum power data obtained by the mathematical model is the optical axis angle of the first film layer.

[0016] Optionally, the detection component includes: a phase delay element, a polarizer, and a detection module arranged sequentially, wherein the optical composite film is located between the light source component and the phase delay element, and the phase delay element rotates at an angular frequency ω;

[0017] Obtaining the optical axis angle of the second film layer based on the optical parameters measured by the detection component specifically includes:

[0018] The polarization parameters of the light emitted from the optical composite film are obtained based on the light intensity of the light emitted from the polarizer measured by the detection module.

[0019] The optical axis angle of the second film layer is obtained based on the polarization parameters of the light emitted from the optical composite film and the straight edge angle.

[0020] Optionally, the detection component includes: an analyzer and an optical power meter arranged sequentially, with the optical composite film located between the light source component and the analyzer;

[0021] Obtaining the optical axis angle of the second film layer based on the optical parameters measured by the detection component specifically includes:

[0022] Based on the power data measured by the optical power meter and the change of the analyzer rotation angle, a data model between the power data and the rotation angle is established, and the analyzer rotation angle corresponding to the extreme value of the power data is calculated.

[0023] The optical axis angle of the second film is obtained based on the rotation angle of the analyzer.

[0024] Optionally, the light source assembly includes a laser, the wavelength of the light emitted by the laser being matched with the wavelength corresponding to the second film layer.

[0025] Optionally, the first film layer is a reflective polarizing film or a polarizing film, and the second film layer is a phase retardation film.

[0026] Optionally, the phase delayer is a quarter-wave plate, and the polarizer is a horizontal linear polarizer.

[0027] Optionally, obtaining the polarization parameters of the light emitted from the optical composite film based on the light intensity of the light emitted from the polarizer measured by the detection module specifically includes:

[0028] The intensity of the light emitted from the polarizer is obtained when the angle between the fast axis of the phase delay element and the horizontal direction is α, where α = ωt, and t is the rotation time of the phase delay element;

[0029] Based on the intensity of the light emitted from the polarizer, the Stokes vector of the light emitted from the optical composite film is obtained;

[0030] The polarization parameters of the emitted light from the optical composite film are obtained based on the Stokes vector of the emitted light.

[0031] Optionally, obtaining the Stokes vector of the light emitted from the optical composite film based on the intensity of the light emitted from the polarizer specifically includes:

[0032] A model is established to determine the relationship between the intensity of the light emitted from the polarizer and the Stokes vector of the light emitted from the optical composite film.

[0033] Perform a Fourier transform on the relationship model and obtain the Fourier transform coefficients based on the intensity of the light emitted from the polarizer;

[0034] The Stokes vector of the emitted light from the optical composite film is obtained based on the Fourier transform coefficients.

[0035] Optionally, the model for obtaining the relationship between the intensity of the polarizer's emitted light and the Stokes vector of the emitted light from the optical composite film specifically includes:

[0036] Let Sm be the Stokes vector of the light emitted from the optical composite film;

[0037] Based on the Stokes vector Sm, obtain the Stokes vector S of the emitted light from the phase delay element. ′ ;

[0038] According to the Stokes vector S ′ Obtain the Stokes vector Sout of the light emitted from the polarizer;

[0039] Based on the Stokes vector Sout, a relationship model is obtained between the intensity of the polarizer's emitted light and the Stokes vector of the optical composite film's emitted light.

[0040] Optionally, the Stokes vector S of the emitted light from the phase delay element is obtained based on the Stokes vector Sm. ′ Specifically, it includes:

[0041] Based on the Stokes vector Sm and the Mueller matrix of the phase retardation element with an angle α between the fast axis and the horizontal direction, the Stokes vector S of the emitted light from the phase retardation element is obtained. ′ .

[0042] Optionally, according to the Stokes vector S ′ Obtaining the Stokes vector Sout of the polarizer-emitted light specifically includes:

[0043] According to the Stokes vector S ′ And the Mueller matrix of the polarizer, to obtain the Stokes vector Sout of the polarizer's outgoing light.

[0044] Optionally, the phase delay element rotating at an angular frequency ω specifically includes:

[0045] The phase delay element is driven by a stepper motor to rotate at an angular frequency ω, where the number of steps of the stepper motor is n, the step size is aj, and α = ωt = n × aj.

[0046] Secondly, a detection system for the relative angle of optical composite films is provided. The detection system includes: a light source assembly and a detection assembly;

[0047] The light source assembly is used to emit linearly polarized light with multiple fields of view;

[0048] The detection component is used to detect the relative angle between the optical composite film under test;

[0049] When the optical composite film to be tested is placed between the light source assembly and the detection assembly, the optical composite film and the detection assembly are arranged along the same optical axis.

[0050] Optionally, the detection assembly includes: a phase delay element, a polarizer, and a detection module, wherein the phase delay element rotates at an angular frequency ω;

[0051] When the optical composite film to be tested is placed between the light source assembly and the phase delay element, the optical composite film, the phase delay element, the polarizer, and the detection module are arranged sequentially along the same optical axis.

[0052] Optionally, the detection component includes: an analyzer and an optical power meter;

[0053] When the optical composite film to be tested is placed between the light source assembly and the analyzer, the optical composite film, the analyzer, and the optical power meter are arranged sequentially along the same optical axis.

[0054] Optionally, the light source assembly includes: a light source, a fast reflector, a lens group, and a polarizer, wherein the lens group includes at least one lens;

[0055] The light emitted from the light source passes sequentially through the fast reflector, the lens group, and the polarizer before being projected onto the optical composite film under test.

[0056] Optionally, it also includes a stepper motor that drives the phase delay element to rotate at an angular frequency ω.

[0057] In the technical solution provided in this application embodiment, the optical axis angle of the first film layer is determined by the power data measured by the detection component and the straight edge angle of the optical composite film captured by the vision camera; the optical axis angle of the second film layer is determined according to the optical parameters measured by the detection component; and the relative angle of the optical composite film is determined based on the optical axis angles of the first and second film layers. The method for detecting the relative angle of the optical composite film provided in this application embodiment reduces costs and avoids destructive film-tearing detection, making it applicable to production lines.

[0058] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0059] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0060] Figure 1 The diagram shows the structure of the optical composite film relative angle detection system provided in this application embodiment. Figure 1 .

[0061] Figure 2 The diagram shows the structure of the optical composite film relative angle detection system provided in this application embodiment. Figure 2 .

[0062] Explanation of reference numerals in the attached figures:

[0063] 1. Light source assembly; 10. Light source; 11. Fast reflector; 12. First lens; 13. Second lens; 14. Polarizer;

[0064] 2. Optical composite film under test; 3. Phase delay element; 4. Polarizer; 5. Detection module; 6. Vision camera; 7. Polarizer; 8. Optical power meter. Detailed Implementation

[0065] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0066] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0067] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0068] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0069] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0070] VR optical composite films are generally formed by combining any two of the following: polarizing film (POL film), reflective polarizing film (RP film), and phase retardation film (QWP film). Typically, a polarizing film (POL film) is combined with a quarter-wave plate (QWP film), or a reflective polarizing film (RP film) is combined with a phase retardation film (QWP film). VR optical composite films, when combined with lens groups, form optical modules with folded optical paths. The imaging quality of these modules is affected by the relative angle of the optical composite films; even slight angular differences can significantly impact imaging performance, as well as the user experience and eye comfort. Therefore, relative angle detection of the optical composite films is essential.

[0071] Currently, there are two methods for detecting the relative angles of optical composite films. The first method is to detect the relative angles of the optical composite films using a polarimeter, and the second method is to detect the relative angles of the optical composite films by destructive tearing.

[0072] The method of detecting the relative angle of optical composite films using a polarimeter utilizes the known Stokes vector in the detection optical path and the light intensity detected by the detector. Combined with Fourier analysis, the Mueller matrix of the unknown polarization film is detected, thereby obtaining the optical axis angle information and the relative angle. The advantage of this detection method is that it does not require tearing the film to detect composite materials and the detection speed is fast. However, most of its core technologies are mastered by foreign countries and it is expensive.

[0073] The method of detecting the relative angle of optical composite films by destructive film removal involves first detecting the angle of the transmission axis of the reflective polarizing film, then detecting the angle of the fast or slow axis of the phase retardation film after removing the reflective polarizing film, and finally calculating the relative angle between the transmission axis of the reflective polarizing film and the fast or slow axis of the phase retardation film. This detection method is suitable for spot checks after lens film application and for film calibration during the R&D stage, but it cannot be applied to mass production on the production line.

[0074] To address the aforementioned technical issues, this application provides a novel method and system for detecting the relative angle of optical composite films. This method reduces costs and eliminates the need for film removal when detecting the relative angle of optical composite films. Specifically, the method provided in this application is applicable to the detection of optical composite films formed by combining two or more film layers.

[0075] The method and system for detecting the relative angle of optical composite films provided in this application will be described in detail below with reference to the accompanying drawings.

[0076] According to one embodiment of this application, a method for detecting the relative angle of an optical composite film is provided. This detection method is applied to a system for detecting the relative angle of an optical composite film. The system for detecting the relative angle of an optical composite film includes: a light source assembly 1 and a detection assembly, with a test optical composite film 2 disposed between the light source assembly 1 and the detection assembly. The test optical composite film 2 includes a first film layer and a second film layer, wherein the first film layer selectively allows polarized light to pass through, and the second film layer converts the polarization state of the polarized light.

[0077] The light source assembly 1 is used to emit linearly polarized light with multiple fields of view. The detection assembly is used to detect the optical axis angle of the first film layer and the optical axis angle of the second film layer in the optical composite film, and to obtain the relative angle of the optical composite film based on the optical axis angles of the first film layer and the second film layer.

[0078] The optical composite film includes a first film layer and a second film layer. The first film layer can be a reflective polarizing film (RP film) or a polarizing film (POL film), and the second film layer can be a phase retardation film (QWP film). For example, the second film layer can be a quarter-phase retardation film.

[0079] When the optical composite film 2 to be tested is rotatably disposed between the light source assembly 1 and the detection assembly, the first film layer is disposed closer to the light source assembly 1 than the second film layer. Specifically, when the optical composite film is disposed between the light source assembly 1 and the detection assembly, the linearly polarized light emitted from the light source assembly 1 first passes through the first film layer, then passes through the second film layer and is projected onto the detection assembly.

[0080] The method for detecting the relative angle of optical composite films includes the following steps:

[0081] Step 1: Control the linearly polarized light from multiple fields of view to be projected onto the detection component through the optical composite film;

[0082] Step 2: Obtain the straight edge angle of the optical composite film, wherein the straight edge angle is the angle between the straight edge of the optical composite film and the reference line, and the reference line is the vertical coordinate axis in the visual camera coordinate system;

[0083] Step 3: Obtain the optical axis angle of the first film layer based on the straight edge angle and the power data measured by the detection component;

[0084] Step 4: Obtain the optical axis angle of the second film layer based on the optical parameters measured by the detection component;

[0085] Step 5: Obtain the relative angle between the optical composite films based on the optical axis angles of the first film layer and the second film layer.

[0086] In step 1, linearly polarized light with multiple fields of view is controlled to pass through the optical composite film under test 2 and the detection component. For example, the light source component 1 emits linearly polarized light with multiple fields of view, which, after passing through the optical composite film under test 2, is finally received by the detection component.

[0087] In one specific embodiment, the optical composite film includes an RP film and a QWP film. The light source assembly generates linearly polarized light with multiple fields of view, which sequentially passes through the RP film and the QWP film before being received by the detection assembly. The optical composite film is rotatably disposed between the light source assembly 1 and the detection assembly. For example, the optical composite film is rotated by an electric wheel.

[0088] Alternatively, in another embodiment, the optical composite film includes a POL film and a QWP film. The light source assembly generates linearly polarized light with multiple fields of view, such that the linearly polarized light with multiple fields of view passes sequentially through the POL film and the QWP film before being received by the detection assembly. The optical composite film is rotatably disposed between the light source assembly 1 and the detection assembly. For example, the optical composite film is rotated by an electric wheel.

[0089] In the embodiments of this application, RP film and QWP film are used as examples for illustration.

[0090] In one example, refer to Figure 1 The detection assembly includes a phase retardation element 3, a polarizer 4, and a detection module 5, wherein the phase retardation element 3 rotates at an angular frequency ω. Linearly polarized light controlling multiple fields of view sequentially passes through an RP film, a QWP film, the phase retardation element 3, and the polarizer 4 before being projected onto the detection module 5. For example, the light source assembly 1 emits linearly polarized light with multiple fields of view, which sequentially passes through an RP film, a QWP film, the phase retardation element 3 rotating at an angular frequency ω, and the polarizer 4, and is finally received by the detection module 5. For example, the detection module 5 can be a CCD camera.

[0091] In another example, refer to Figure 2 The detection component includes an analyzer 7 and an optical power meter 8. Linearly polarized light with multiple fields of view is sequentially projected onto the optical power meter 8 through an RP film, a QWP film, and the analyzer 7. For example, the light source component 1 emits linearly polarized light with multiple fields of view, which sequentially passes through the RP film, the QWP film, and the analyzer 7, and is finally received by the optical power meter 8.

[0092] In step 2, the straight edge angle of the optical composite film is obtained, wherein the straight edge angle is the angle between the straight edge of the optical composite film and the reference line, and the reference line is the vertical coordinate axis in the visual camera coordinate system;

[0093] In this step, the angle between the straight edge of the optical composite film and the vertical coordinate axis determined by the vision camera 6 is obtained through the vision camera 6.

[0094] In one specific embodiment, a surface light source is provided to illuminate the side of the optical composite film. A vision camera 6 captures images of the straight edge segment of the optical composite film, obtaining the angle between the straight edge segment of the optical composite film and the vertical coordinate axis determined by the vision camera 6's own coordinates. For example, the optical composite film includes a first film layer and a second film layer, which are bonded together. The straight edge segments of the first film layer and the second film layer are bonded together to form the straight edge segment of the optical composite film.

[0095] Specifically, upon receiving the materials, the POL film, RP film, and QWP film all include an arc-shaped portion and a straight edge segment connected to the arc-shaped portion. The straight edge segment can be formed by cutting, for example, by cutting a circular film to form an optical film with a straight edge segment. These optical films with straight edge segments are then laminated together to form an optical composite film with straight edge segments.

[0096] The vision camera 6 is fixedly positioned, while the optical composite film 2 under test is rotatably positioned between the light source assembly and the detection assembly. During the rotation of the optical composite film, the straight edge segment of the optical composite film rotates along with it. Therefore, the straight edge angle of the optical composite film acquired by the vision camera 6 also changes in real time. For example, based on the rotation of the light source composite film, the straight edge angle of the optical composite film can gradually decrease or gradually increase in a regular manner, or the straight edge angle of the optical composite film can change irregularly.

[0097] In step 3, the optical axis angle of the first film layer is obtained based on the straight edge angle and the power data measured by the detection component. For example, the straight edge angle of the optical composite film is obtained by the vision camera 6, and the power data of the light emitted from the optical composite film is measured by the detection component. The straight edge angle of the first film layer is obtained based on the straight edge angle and the power data.

[0098] Specifically, during the rotation of the optical composite film between the light source assembly 1 and the detection assembly, the vision camera 6 and the detection assembly work synchronously. The vision camera 6 acquires the straight edge angle of the optical composite film, while the detection assembly measures the power data of the light emitted from the optical composite film.

[0099] It should be noted that the embodiments of this application define the positions of the first and second films. The linearly polarized light emitted from the light source assembly must first pass through the first film and then through the second film. The first film selectively allows a certain type of polarized light to pass through, while the second film changes the polarization state of the polarized light. Therefore, after the linearly polarized light emitted from the light source assembly passes through the first film, the power of the polarized light does not change, and the power data measured by the detection component is the power of the polarized light emitted from the first film.

[0100] For example, in one instance, refer to Figure 1 The detection component includes a phase retardation element 3, a polarizer 4, and a detection module 5, which can be a CCD camera. Linearly polarized light emitted from the light source component passes through an RP film, then sequentially through a QWP film, a phase retardation element 3, a polarizer 4, and a detection module 5. The power of the polarized light emitted from the RP film is consistent with the power of the polarized light emitted from the QWP film, the phase retardation element, and the polarizer. In other words, the power of the emitted light detected by the CCD camera is also the power of the polarized light emitted from the RP film.

[0101] Or in another example, refer to Figure 2The detection component includes an analyzer 7 and an optical power meter 8. The linearly polarized light emitted from the light source component passes through the RP film, and then sequentially through the QWP film, the analyzer 7, and the optical power meter 8. The power of the polarized light emitted from the RP film is the same as the power of the polarized light emitted from the QWP film and the power of the polarized light emitted from the analyzer 7. In other words, the power of the emitted light detected by the optical power meter 8 is also the power of the polarized light emitted from the RP film.

[0102] In this step, the optical axis angle of the first film layer is obtained based on the straight edge angle and the power data measured by the detection component. Specifically, a curve is fitted using the detected power data and the straight edge angle data, and the straight edge angle corresponding to the minimum detected optical power is the optical axis angle of the first film layer.

[0103] In a specific example, a mathematical model is established by fitting data based on the power data measured by the detection component and the straight edge angle of the optical composite film. The straight edge angle of the optical composite film corresponding to the minimum power data obtained by the mathematical model is the optical axis angle of the first film layer.

[0104] During the rotation of the optical composite film, the detection component measures multiple sets of power data in real time, and the vision camera 6 measures multiple sets of straight edge angles in real time. A mathematical model is established by fitting these multiple sets of power data and straight edge angles, and this model conforms to a parabolic equation. Substituting the minimum power data into this mathematical model, the corresponding straight edge angle of the optical composite film is the optical axis angle of the first film layer.

[0105] In one specific embodiment, refer to Figure 1 The detection components include a phase retardation element 3, a polarizer 4, and a detection module 5, which can be a CCD camera. When detecting the transmission axis angle of the RP, the optical composite film 2 (RP+QWP) under test is rotated, and the power of the emitted light is detected by the CCD camera. Simultaneously, a vision camera captures an image, providing the angle between the straight edge of the optical composite film 2 under test and the vertical direction determined by the camera's own coordinates. A curve is fitted using the detected power data and the straight edge angle data. The straight edge angle corresponding to the minimum detected optical power is the deviation angle between the actual value of the RP transmission axis and the ideal value, i.e., the optical axis angle of the RP film.

[0106] In another specific embodiment, refer to Figure 2The detection components include an analyzer 7 and an optical power meter 8. When detecting the transmission axis angle of the RP, the analyzer 7 is rotated to align its transmission axis direction parallel to that of the polarizer. The optical composite film under test is rotated, and the power of the emitted light is detected by the optical power meter. Simultaneously, a vision camera captures an image, providing the angle between the straight edge of the optical composite film under test and the vertical direction determined by the camera's own coordinates. A curve is fitted using the detected power data and the straight edge angle data. The straight edge angle corresponding to the minimum detected optical power is the deviation angle between the actual value of the RP transmission axis and the ideal value, i.e., the optical axis angle of the RP film.

[0107] In step 4, the optical axis angle of the second film is obtained based on the optical parameters measured by the detection component.

[0108] In this step, the optical axis angle of the second film is obtained based on the optical parameters measured by the detection components. For example, different optical parameters are measured based on different combinations of detection components, and then the optical axis angle of the second film is obtained based on the measured optical parameters.

[0109] In one example, refer to Figure 1 The detection component includes a phase delay element 3, a polarizer 4, and a detection module 5 arranged sequentially. The optical composite film is located between the light source component and the phase delay element, and the phase delay element rotates at an angular frequency ω.

[0110] In this example, the optical axis angle of the second film layer is determined based on the azimuth angle and the right-side angle of the light emitted from the optical composite film. Specifically, obtaining the optical axis angle of the second film layer based on the optical parameters measured by the detection component includes the following steps:

[0111] Step 401: Based on the light intensity of the light emitted from the polarizer measured by the detection module, obtain the polarization parameters of the light emitted from the optical composite film.

[0112] Step 402: Obtain the optical axis angle of the second film layer based on the polarization parameters of the light emitted from the optical composite film and the straight edge angle.

[0113] In step 401, the polarization parameters of the light emitted from the optical composite film are obtained based on the light intensity of the polarizer emitted by the detection module. The polarization parameter is the azimuth angle.

[0114] Specifically, by detecting the intensity of the light emitted from the polarizer 4 received by the detection module 5, the azimuth angle of the light emitted from the optical composite film is obtained based on the Stokes vector and the Mueller matrix. Since the optical composite film is rotatably mounted on the light source assembly and the phase delay element 3, and the phase delay element 3 rotates at an angular frequency ω, the azimuth angle of the light emitted from the optical composite film, calculated based on the Stokes vector and the Mueller matrix, also changes in real time due to the intensity of the light emitted from the polarizer 4 received by the detection module 5. For example, based on the rotation of the optical composite film and the phase delay element 3, the azimuth angle of the polarized light emitted from the optical composite film can gradually decrease or gradually increase in a regular manner, or it can change irregularly.

[0115] When the detection module 5 detects that the fast axis of the phase delay element 3 makes an angle α (α = ωt) with the horizontal direction, and considering the intensity of polarized light emitted from multiple fields of view by the polarizer 4, the azimuth angle of the polarized light emitted from the optical composite film is calculated based on the Stokes vector and the Mueller matrix, according to the intensity of the polarized light from the multiple fields of view emitted from the polarizer 4. For example, if the optical composite film is a composite layer of RP film and QWP film, the azimuth angle of the polarized light emitted from the optical composite film is calculated. For example, the polarized light can be circularly polarized or elliptically polarized. When the polarized light is elliptically polarized, the azimuth angle of the major axis of the elliptically polarized light is calculated.

[0116] In step 402, the optical axis angle of the second film layer is obtained based on the polarization parameters and straight edge angle of the light emitted from the optical composite film. For example, a relationship model is established based on the azimuth angle and straight edge angle of the light emitted from the optical composite film, and the optical axis angle of the second film layer is determined based on this relationship model.

[0117] Specifically, the acquisition of the straight edge angle of the optical composite film via vision camera 6 and the acquisition of the azimuth angle of the emitted light from the optical composite film via detection module 5 are performed simultaneously. Therefore, within the same time period, the acquired straight edge angle and the acquired azimuth angle of the emitted light from the optical composite film are in one-to-one correspondence. By fitting the acquired azimuth angle of the emitted light from the optical composite film under test with the straight edge angle of the optical composite film captured by vision camera 6, a relationship model between the azimuth angle of the emitted light from the optical composite film and the straight edge angle can be obtained.

[0118] Since the optical composite film is rotatably positioned between the light source assembly and the phase delay element 3, in step 02, during the rotation of the optical composite film, the vision camera 6 acquires multiple straight-edge angles of the optical composite film. For example, the acquired multiple straight-edge angles are defined as a straight-edge angle group.

[0119] Since the optical composite film is rotatably positioned between the optical component and the phase delay element 3, and the phase delay element 3 is also rotatably positioned, in step 02, during the rotation of the optical composite film and the phase delay element 3, the azimuth angles of the emitted rays from multiple optical composite films are acquired. For example, the azimuth angles of the emitted rays from multiple different optical composite films are defined as an azimuth angle group.

[0120] Data fitting is performed using a one-to-one correspondence of straight edge angle groups and azimuth angle groups. Based on the fitted relationship model, the optical axis angle of the second optical axis is determined. Specifically, by inputting the azimuth angle of the ideal outgoing light ray of the optical composite film 2 under test, the straight edge angle of the optical composite film 2 under test can be obtained. The straight edge angle of the optical composite film can characterize the angle between the polarization axis of the second film layer and the horizontal axis, that is, it can characterize the optical axis angle of the second film layer.

[0121] In one specific embodiment, the wavelength of the laser in the light source assembly corresponds to the wavelength of the QWP film, and the optical composite film is a composite of the RP film and the QWP film. The phase delay element is a quarter-wave plate, the polarizer is a horizontal linear polarizer, and the detection module is a CCD camera.

[0122] When detecting the fast or slow axis angle of the QWP film, the optical composite film 2 under test is rotated. Since the incident linearly polarized light will be emitted as elliptically or circularly polarized light after passing through the optical composite film, the detection of circularly polarized light indicates that the relative angle between the fast and slow axes of the QWP and the transmission axis of the RP is 45°. When elliptically polarized light is detected, the major and minor axes of the elliptically polarized light will coincide with the directions of the fast and slow axes of the QWP. The fast and slow axes of the QWP are perpendicular to each other. The incident linearly polarized light is decomposed into two components along the coordinate system formed by the fast and slow axes of the QWP. The direction in which the component is larger corresponds to the direction of the major axis of the elliptically polarized light. For example, a quarter-wave plate rotating at angular frequency ω, a horizontal linear polarizer, and a CCD camera can directly detect the major axis azimuth angle of the emitted elliptically polarized light. During the rotation of the optical composite film 2 under test, a vision camera simultaneously captures images, providing the angle between the straight edge of the optical composite film under test and the vertical direction determined by the camera's own coordinates. Thus, the straight edge angle corresponding to the ideal value of the QWP fast axis or slow axis can be obtained, which is the QWP fast axis or slow axis angle.

[0123] Or, in another example, refer to Figure 2 The detection component includes: an analyzer 7 and an optical power meter 8 arranged in sequence, with the optical composite film located between the light source component and the analyzer 7.

[0124] In this example, the optical axis angle of the second film is determined based on the power parameters obtained from the optical power meter and the rotation angle of the analyzer. Specifically, obtaining the optical axis angle of the second film based on the optical parameters measured by the detection component includes the following steps:

[0125] Step 411: Based on the change of power data measured by the optical power meter 8 with the rotation angle of the analyzer 7, establish a data model between the power data and the rotation angle, and calculate the rotation angle of the analyzer 7 corresponding to the extreme value of the power data.

[0126] Step 412: Obtain the optical axis angle of the second film layer based on the rotation angle of the analyzer 7.

[0127] In one specific embodiment, the wavelength of the light source 10 (which can be a laser) in the light source assembly corresponds to the wavelength of the QWP film, and the light source assembly includes a polarizer. The optical composite film is a composite film of an RP film and a QWP film.

[0128] Specifically, when detecting the transmission axis angle of the RP, the analyzer 7 is rotated to align its transmission axis direction parallel to that of the polarizer. During the rotation of the optical composite film 2 under test, the power of the emitted light is detected by the optical power meter 8. Simultaneously, a vision camera captures an image, providing the angle between the straight edge of the optical composite film 2 and the vertical direction determined by the camera's own coordinates. A curve is fitted using the detected power data and the straight edge angle data; the straight edge angle corresponding to the minimum detected optical power is the transmission axis angle of the RP.

[0129] Before detecting the fast or slow axis angle of QWP, rotate the optical composite film under test by 90° (where the position of the optical composite film when detecting the transmission axis angle of RP is taken as the initial position), at which time the light intensity passing through the optical composite film under test 2 is the maximum.

[0130] During the rotation of the optical composite film 2 under test, the incident linearly polarized light will be emitted as elliptically or circularly polarized light after passing through the optical composite film. After rotating the analyzer 7 a full circle, if the power detected by the optical power meter 8 remains unchanged, it indicates that the emitted light is circularly polarized, meaning the relative angle between the fast and slow axes of the QWP and the transmission axis of the RP is 45°. When the emitted light is elliptically polarized, the major and minor axes of the elliptically polarized light will coincide with the directions of the fast and slow axes of the QWP. The fast and slow axes of the QWP are perpendicular to each other. The incident linearly polarized light is decomposed into two components along the coordinate system formed by the fast and slow axes of the QWP. The direction in which the component is larger corresponds to the direction of the major axis of the elliptically polarized light. After rotating the analyzer 7 a full circle, the positions of the power maximum and minimum are determined, and the angle of rotation of the analyzer 7 to the power maximum or minimum position is recorded. The angle of rotation of the analyzer 7 plus or minus the angle detected by the transmission axis of the RP is the angle of the fast or slow axis of the QWP.

[0131] In step 5, the relative angle between the optical composite films is obtained based on the optical axis angles of the first film layer and the second film layer.

[0132] In this step, the relative angle of the optical composite film can be obtained by subtracting the optical axis angle of the first film layer from the optical axis angle of the second film layer.

[0133] It should be noted that when the detection components are analyzer 7 and optical power meter 8, the angle of rotation of analyzer 7 to the position of maximum or minimum power is recorded. The angle of rotation of analyzer 7 is the relative angle between the fast or slow axis of QWP and the transmission axis of RP.

[0134] Therefore, in this embodiment, the optical axis angle of the first film layer is determined by the power data measured by the detection component and the straight edge angle of the optical composite film captured by the vision camera; the optical axis angle of the second film layer is determined according to the optical parameters measured by the detection component; and the relative angle of the optical composite film is determined according to the optical axis angles of the first and second film layers. The method for detecting the relative angle of the optical composite film provided in this embodiment avoids destructive film tearing detection while reducing costs, and can be applied to production lines.

[0135] In one example, the light source assembly includes a laser whose emitted light wavelength matches the wavelength corresponding to the second film layer.

[0136] In this embodiment, the light source assembly includes a laser, and the wavelength of the laser-emitted light is defined relative to the QWP wavelength. This ensures that when the incident linearly polarized light passes through the RP+QWP optical composite film and emits circularly polarized light, the relative angle between the fast and slow axes of the QWP and the transmission axis of the RP is 45°, simplifying the detection process.

[0137] For example, when the waveplate of the laser beam does not match the wavelength of the QWP, and when the relative angle between the fast and slow axes of the QWP and the transmission axis of the RP is 45°, the incident linearly polarized light will not emit circularly polarized light after passing through the RP+QWP optical composite film, which complicates the detection process.

[0138] In one example, the phase delayer is a quarter-wave plate, and the polarizer is a horizontal linear polarizer.

[0139] In this embodiment, the types of phase delay element 3 and polarizer 4 are limited. The Mueller matrix of quarter-wave plate and horizontal linear polarizer is relatively simple, which can reduce the difficulty of obtaining the azimuth angle of the light emitted from the optical composite film.

[0140] In one example, obtaining the polarization parameters of the light emitted from the optical composite film based on the light intensity of the light emitted from the polarizer measured by the detection module specifically includes the following steps:

[0141] Step 01: Obtain the intensity of the light emitted from the polarizer when the angle between the fast axis of the phase delay element and the horizontal direction is α, where α = ωt, and t is the rotation time of the phase delay element;

[0142] Step 02: Obtain the Stokes vector of the light emitted from the optical composite film based on the intensity of the light emitted from the polarizer;

[0143] Step 03: Obtain the polarization parameters of the emitted light from the optical composite film based on the Stokes vector of the emitted light.

[0144] Specifically, based on the light intensity of the light emitted from the polarizer 4 measured by the detection module 5, the polarization parameters of the light emitted from the optical composite film are obtained, wherein the polarization parameters are the azimuth angles of the light emitted from the optical composite film.

[0145] In step 01, the intensity of the light emitted from the polarizer 4 is obtained when the angle between the fast axis of the phase delay element 3 and the horizontal direction is α, where α = ωt. Specifically, the polarized light from multiple fields of view emitted from the polarizer 4 is ultimately received by the detection module 5. Since the phase delay element 3 is constantly rotating at an angular frequency ω, the detection module 5 can detect in real time the intensity of the polarized light from multiple fields of view emitted from the polarizer 4 when the angle between the fast axis of the phase delay element 3 and the horizontal direction is α.

[0146] In step 02, when the detection module 5 detects that the angle between the fast axis of the phase delay element 3 and the horizontal direction is α, and considering the intensity of the polarized light emitted from the polarizer 4 across multiple fields of view, the Stokes vector of the light emitted from the optical composite film can be obtained based on the intensity of the polarized light emitted from the polarizer 4 across multiple fields of view. The Stokes vector of the light emitted from the optical composite film characterizes the polarization state and intensity of the light beam.

[0147] For example, the Stokes vector of the emitted light from the optical composite film is Sm.

[0148]

[0149] Where S0 represents the total light intensity, S1 represents the light intensity difference between horizontally and vertically linearly polarized light, S2 represents the light intensity difference between 45-degree and -45-degree linearly polarized light, and S3 represents the light intensity difference between right-handed and left-handed circularly polarized light.

[0150] S0, S1, S2, and S3 can all be represented by the intensity of multiple field-of-view polarized lights emitted through polarizer 4.

[0151] In step 03, the azimuth angle of the emitted light from the optical composite film can be obtained based on the calculated Stokes vector Sm. For example, the azimuth angle of the emitted light from the optical composite film is ψ.

[0152] The azimuth angle ψ of the light emitted from the optical composite film can be obtained by formula (2);

[0153]

[0154] Therefore, in this embodiment, based on the intensity of multiple field-of-view rays emitted by the polarizer 4 when the angle between the fast axis of the phase delay element 3 and the horizontal direction is α obtained by the detection module, the value of each element (S0, S1, S2 and S3) in formula (1) is calculated, where each element (S0, S1, S2 and S3) is also related to the angle α between the fast axis of the phase delay element 3 and the horizontal direction; then, based on the value of each element calculated in formula (1), the azimuth angle of the light emitted by the optical composite film is calculated according to formula (2).

[0155] In this embodiment, the azimuth angle of the emitted light from the optical composite film is detected by combining the phase delay element 3, which rotates at an angular frequency ω, with the polarizer 4 and the detection module 5. This method enables rapid, accurate, and low-cost detection of the azimuth angle of the emitted light from the optical composite film. Based on the determined azimuth angle of the emitted light from the optical composite film, the optical axis angle of the second film layer is determined.

[0156] In one example, obtaining the Stokes vector of the light emitted from the optical composite film based on the intensity of the light emitted from the polarizer specifically includes the following steps:

[0157] Step 001: Obtain the relationship model between the intensity of the light emitted from the polarizer and the Stokes vector of the light emitted from the optical composite film;

[0158] Step 002: Perform a Fourier transform on the relationship model and obtain the Fourier transform coefficients based on the intensity of the light emitted from the polarizer;

[0159] Step 003: Obtain the Stokes vector of the emitted light from the optical composite film based on the Fourier transform coefficients.

[0160] In step S001, the intensity of the light emitted from polarizer 4 is related to the Stokes vector of the light emitted from the optical composite film and the rotation angle of phase delay element 3. The angle between the fast axis of phase delay element 3 and the horizontal direction is α, where α = ωt.

[0161] For example, if the phase delay element 3 is a quarter-wave plate and the polarizer 4 is a horizontal linear polarizer, the relationship between the intensity of the light emitted from the polarizer 4 and the Stokes vector of the light emitted from the optical composite film is expressed as follows:

[0162]

[0163] In formula (3), α is the angle between the fast axis of the phase delay element 3 and the horizontal direction, and S0, S1, S2 and S3 are all elements in the Stokes vector matrix of the light rays emitted from the optical composite film.

[0164] In step S002, a Fourier transform is performed on formula (3), and the Fourier transform coefficients are obtained based on the intensity of the light emitted from polarizer 4. Specifically, the relationship between the Fourier transform coefficients and the intensity of the detected light emitted from the polarizer can be obtained through the Fourier transform.

[0165] For example, formula (3) can be written in Fourier series form, where the Fourier series form corresponding to formula (3) is formula (4):

[0166]

[0167] Then, by applying a Fourier transform to formula (4), the relationship between the Fourier transform coefficients A, B, C, and D and the intensity of the detected polarizer 4 emitted light can be obtained. For example, formula (5) below shows the relationship between the Fourier transform coefficient A and the intensity of the detected polarizer emitted light; formula (6) shows the relationship between the Fourier transform coefficient B and the intensity of the detected polarizer emitted light; formula (7) shows the relationship between the Fourier transform coefficient C and the intensity of the detected polarizer emitted light; and formula (8) shows the relationship between the Fourier transform coefficient D and the intensity of the detected polarizer emitted light.

[0168]

[0169]

[0170]

[0171]

[0172] In step S003, the Stokes vector of the emitted light from the optical composite film is obtained based on the Fourier transform coefficients. Specifically, the parameters in the Stokes vector matrix of the emitted light from the optical composite film are obtained according to the above formulas (5)-(8).

[0173] Specifically, according to formulas (3) and (4), the relationship between the Fourier transform coefficients A, B, C, and D and the elements S0, S1, S2, and S3 in the Stokes vector matrix of the emitted light from the optical composite film can be obtained, where:

[0174]

[0175] B = S3 (10)

[0176]

[0177]

[0178] According to formulas (9) and (12), we can know that:

[0179] S0=AC (13)

[0180] S1=2C (14)

[0181] S2 = 2D (15)

[0182] S3=B (16)

[0183] Therefore, according to formulas (5)-(8) and (13)-(16), the parameters in the Stokes vector matrix of the emitted light from the optical composite film can be obtained, and thus the Stokes vector of the emitted light from the optical composite film can be obtained. Based on the obtained Stokes vector of the emitted light from the optical composite film, the azimuth angle of the emitted light from the optical composite film can be calculated using formula (2).

[0184] In one example, the model for obtaining the relationship between the intensity of the polarizer-emitted light and the Stokes vector of the optical composite film-emitted light specifically includes the following steps:

[0185] Step 0001: Set the Stokes vector of the light emitted from the optical composite film to Sm;

[0186] Step 0002: Obtain the Stokes vector S of the emitted light from the phase delay element based on the Stokes vector Sm. ′ ;

[0187] Step 0003: Based on the Stokes vector S ′ Obtain the Stokes vector Sout of the light emitted from the polarizer;

[0188] Step 0004: Based on the Stokes vector Sout, obtain the relationship model between the intensity of the polarizer-emitted light and the Stokes vector of the optical composite film-emitted light.

[0189] Specifically, in step S0001, the Stokes vector of the light emitted from the optical composite film is first set to Sm.

[0190] For example, let the Stokes vector of the light emitted from the optical composite film be:

[0191] Where S0 represents the total light intensity, S1 represents the light intensity difference between horizontally and vertically linearly polarized light; S2 represents the light intensity difference between 45-degree and -45-degree linearly polarized light; and S3 represents the light intensity difference between right-handed and left-handed circularly polarized light.

[0192] In step S0002, the Stokes vector S of the emitted light from the phase delay element 3 is obtained based on the Stokes vector Sm. ′ Specifically, based on the theory that the Stokes vector of the light emitted from a certain component is the product of the Mueller matrix of that component and the Stokes vector of the light emitted from the previous component, the Stokes vector of the light emitted from the phase delay element 3 is obtained.

[0193] For example, based on the Stokes vector Sm and the Mueller matrix of the phase retardation element 3 with an angle α between the fast axis and the horizontal direction, the Stokes vector S of the emitted light from the phase retardation element 3 can be obtained. ′ .

[0194] In a specific embodiment, the phase delay element 3 is a quarter-wave plate, and the Mueller matrix of the quarter-wave plate, which has an angle α between the fast axis and the horizontal direction, can be expressed as formula (17):

[0195]

[0196] The quarter-wave plate rotates at an angular velocity ω (α = ωt).

[0197] After the light emitted from the optical composite film passes through a rotating quarter-wave plate, the Stokes vector of the emitted light is given by formula (18):

[0198]

[0199] It should be noted that the phase delay element 3 can also be a half-wave plate. The half-wave plate allows the optical composite film to exit, and the light emitted from the half-wave plate is linearly polarized. After the light emitted from the optical composite film passes through the rotating half-wave plate, the Stokes vector of the emitted light is the product of the Mueller matrix of the half-wave plate and the Stokes vector of the light emitted from the optical composite film.

[0200] In step S0003, according to the Stokes vector S ′ Obtain the Stokes vector S of the emitted light from the polarizer 4. out Specifically, the Stokes vector of the polarizer's output light is obtained based on the theory that the Stokes vector of the light emitted from a certain component is the product of the Mueller matrix of that component and the Stokes vector of the light emitted from the previous component.

[0201] For example, according to the Stokes vector S ′And the Mueller matrix of the polarizer 4, to obtain the Stokes vector S of the light emitted from the polarizer 4. out .

[0202] In one specific embodiment, polarizer 4 is a horizontal linear polarizer. The Mueller matrix of the horizontal linear polarizer (i.e., the Mueller matrix of the transmission axis of the horizontal linear polarizer in the horizontal direction) is expressed by formula (19):

[0203]

[0204] The relationship between the light emitted from the horizontal linear polarizer and the light emitted from the optical composite film is as follows:

[0205] S out =NMS VR (20)

[0206] The light emitted through a horizontal linear polarizer can be represented as follows: That is, the Stokes vector of the light emitted from a horizontal linear polarizer can be represented as follows:

[0207]

[0208] It should be noted that polarizer 4 can also be a circular polarizer. Based on the principle explained above, the Stokes vector of the light rays emitted after passing through the circular polarizer can be obtained.

[0209] In step S0004, according to the Stokes vector S out Obtain the relationship expression between the intensity of the light emitted from the polarizer 4 and the Stokes vector of the light emitted from the optical composite film.

[0210] Specifically, in the calculation, only the emitted light S out The first component, i.e., the total intensity, can be detected, S'0=I(α).

[0211]

[0212] Therefore, the above formula (3) shows the relationship between the intensity of the light emitted from polarizer 4 and the Stokes vector of the light emitted from the optical composite film, where α is the angle between the fast axis of phase delay element 3 and the horizontal direction, and S0, S1, S2 and S3 are all elements in the Stokes vector matrix of the light emitted from the optical composite film. Then, a Fourier transform is performed on formula (3) to obtain the Fourier transform coefficients based on the intensity of the light emitted from polarizer 4. Specifically, the relationship between the Fourier transform coefficients and the intensity of the detected light emitted from the polarizer can be obtained through Fourier transform. Then, by performing a Fourier transform on the above formula (4), the relationship between the Fourier transform coefficients A, B, C and D and the intensity of the detected light emitted from polarizer 4 can be obtained. For example, formula (5) above shows the relationship between the Fourier transform coefficient A and the intensity of the detected polarizer-emitted light, formula (6) shows the relationship between the Fourier transform coefficient B and the intensity of the detected polarizer-emitted light, formula (7) shows the relationship between the Fourier transform coefficient C and the intensity of the detected polarizer-emitted light, and formula (8) shows the relationship between the Fourier transform coefficient D and the intensity of the detected polarizer-emitted light.

[0213] Therefore, based on the above formulas (5)-(8) and (13)-(16), the parameters in the Stokes vector matrix of the emitted light from the optical composite film can be obtained, thus obtaining the Stokes vector of the emitted light from the optical composite film. Based on obtaining the Stokes vector of the emitted light from the optical composite film, the azimuth angle of the emitted light from the optical composite film can be calculated using the above formula (2).

[0214] In one example, the phase delay element rotates at an angular frequency ω, specifically including:

[0215] The phase delay element is driven by a stepper motor to rotate at an angular frequency ω, where the number of steps of the stepper motor is n, the step size is aj, and α = ωt = n × aj.

[0216] In one specific embodiment, the phase delay element 3 is rotated by a stepper motor. For example, the quarter-wave plate is rotated by a stepper motor.

[0217] Specifically, a quarter-wave plate is placed on a fixed base and can be rotated in n steps by a stepper motor: ωt = nα j (α j (where α is the step size and N is the total number of steps). This is based on the formula α = ωt = nα. j By transforming formula (4), we can obtain formula (22).

[0218]

[0219] The Fourier transform can be used to obtain the relationship between the Fourier transform coefficients A, B, C and D and the intensity of the emitted light from the detected polarizer 4. Formulas (23)-(26) show the relationship between the Fourier transform coefficients A, B, C and D and the intensity of the emitted light from the detected polarizer 4.

[0220]

[0221]

[0222]

[0223]

[0224] Thus, in this embodiment of the application, given the step size and number of steps of the stepper motor, and the intensity of the emitted light from the polarizer 4, the Stokes vector of the emitted light from the optical composite film can be obtained. Then, the azimuth angle of the emitted light from the optical composite film is obtained based on the Stokes vector.

[0225] Secondly, a detection system for the relative angle of optical composite films is provided. The detection system includes: a light source assembly and a detection assembly;

[0226] The light source assembly is used to emit linearly polarized light with multiple fields of view;

[0227] The detection component is used to detect the relative angle between the optical composite film under test;

[0228] When the optical composite film to be tested is placed between the light source assembly and the detection assembly, the optical composite film and the detection assembly are arranged along the same optical axis.

[0229] In this embodiment, the optical axis angles of the first and second films are measured using a detection component. Based on these angles, the relative angle between the optical composite films is determined. The optical composite film relative angle detection system provided in this embodiment reduces costs and avoids destructive film-tearing detection, making it applicable to production lines.

[0230] In one example, the detection assembly includes: a phase delay element, a polarizer, and a detection module, wherein the phase delay element rotates at an angular frequency ω;

[0231] When the optical composite film to be tested is placed between the light source assembly and the phase delay element, the optical composite film, the phase delay element, the polarizer, and the detection module are arranged sequentially along the same optical axis.

[0232] In this embodiment, power data and optical parameters are detected by combining a phase delay element rotating at an angular frequency ω with a polarizer and a detection module. The straight edge angle of the optical composite film is acquired by a vision camera 6. Based on the power data and the straight edge angle, the optical axis angle of the first film layer is determined, and based on the optical parameters, the optical axis angle of the second film layer is determined. Finally, the relative angle between the optical composite films is determined based on the optical axis angles of the first and second film layers.

[0233] In one example, the detection components include: an analyzer 7 and an optical power meter 8;

[0234] When the optical composite film 2 to be tested is placed between the light source assembly 1 and the analyzer 7, the optical composite film, the analyzer 7 and the optical power meter 8 are arranged sequentially along the same optical axis.

[0235] In this embodiment, the optical axis angles of the first and second films are determined by rotating the analyzer 7 and using the power data obtained from the optical power meter 8. Finally, the relative angle between the optical composite films is determined based on the optical axis angles of the first and second films.

[0236] In one example, refer to Figure 1 The light source assembly 1 includes: a light source 10, a fast reflector 11, a lens group and a polarizer 14, wherein the lens group includes at least one lens;

[0237] The light emitted from the light source 10 passes sequentially through the fast reflector 11, the lens group, and the polarizer 14 and is projected onto the optical composite film 2 to be tested.

[0238] Specifically, the lens group includes a first lens 12 and a second lens 13. The light emitted from the laser passes through the fast-reflecting mirror 11, the first lens 12, and the second lens 13, wherein... Figure 1 In the image, F1 and F2 are the focal lengths of the first lens 12 and the second lens 13, respectively. After passing through the polarizer 14, they can generate linearly polarized light with multiple fields of view.

[0239] Alternatively, in an alternative embodiment, refer to Figure 2 The light source assembly 1 includes a light source 10 and a polarizer 14.

[0240] In one example, a stepper motor is also included, which drives the phase delay element to rotate at an angular frequency ω.

[0241] In this embodiment, the phase delay element 3 is driven by a stepper motor. Given the step size and number of steps of the stepper motor, and the intensity of the emitted light from the polarizer 4, the Stokes vector of the emitted light from the optical composite film can be obtained. Then, the polarization parameters of the optical composite film are obtained based on the Stokes vector of the emitted light. Finally, the optical axis angle of the second film layer is obtained based on the polarization parameters of the optical composite film.

[0242] The specific implementation of the optical composite film relative angle detection system of this application embodiment can refer to the various embodiments of the optical composite film relative angle detection method described above. Therefore, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0243] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0244] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. 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 application. The scope of this application is defined by the appended claims.

Claims

1. A method for detecting the relative angle of optical composite films, characterized in that, A detection system for the relative angle of optical composite films is provided. The detection system includes a light source assembly and a detection assembly. The optical composite film to be tested is disposed between the light source assembly and the detection assembly. The optical composite film includes a first film layer and a second film layer. The first film layer can selectively allow polarized light to pass through, and the second film layer can convert the polarization state of the polarized light. When the optical composite film is rotatably disposed between the light source assembly and the detection assembly, the first film layer is disposed closer to the light source assembly relative to the second film layer; The detection method includes: Linearly polarized light with multiple fields of view is projected onto the detection component through the optical composite film; Obtain the straight edge angle of the optical composite film, wherein the straight edge angle is the angle between the straight edge of the optical composite film and the reference line, and the reference line is the vertical coordinate axis in the visual camera coordinate system; The optical axis angle of the first film layer is obtained based on the straight edge angle and the power data measured by the detection component. The optical axis angle of the second film is obtained based on the optical parameters measured by the detection component. The relative angle between the optical composite films is obtained based on the optical axis angles of the first film layer and the second film layer.

2. The detection method according to claim 1, characterized in that, Obtaining the optical axis angle of the first film layer based on the power data measured by the detection component and the straight edge angle of the optical composite film specifically includes: A mathematical model is established by fitting the power data measured by the detection component and the straight edge angle of the optical composite film. The straight edge angle of the optical composite film corresponding to the minimum power data obtained by the mathematical model is the optical axis angle of the first film layer.

3. The detection method according to claim 1, characterized in that, The detection assembly includes: a phase delay element, a polarizer, and a detection module arranged sequentially, with the optical composite film located between the light source assembly and the phase delay element, and the phase delay element rotating at an angular frequency ω. Obtaining the optical axis angle of the second film layer based on the optical parameters measured by the detection component specifically includes: The polarization parameters of the light emitted from the optical composite film are obtained based on the light intensity of the light emitted from the polarizer measured by the detection module. The optical axis angle of the second film layer is obtained based on the polarization parameters of the light emitted from the optical composite film and the straight edge angle.

4. The detection method according to claim 1, characterized in that, The detection component includes: an analyzer and an optical power meter arranged in sequence, with the optical composite film located between the light source component and the analyzer; Obtaining the optical axis angle of the second film layer based on the optical parameters measured by the detection component specifically includes: Based on the power data measured by the optical power meter and the change of the analyzer rotation angle, a data model between the power data and the rotation angle is established, and the analyzer rotation angle corresponding to the extreme value of the power data is calculated. The optical axis angle of the second film is obtained based on the rotation angle of the analyzer.

5. The detection method according to claim 1, characterized in that, The light source assembly includes a laser, and the wavelength of the light emitted by the laser matches the wavelength corresponding to the second film layer.

6. The detection method according to claim 1, characterized in that, The first film layer is a reflective polarizing film or a polarizing film, and the second film layer is a phase delay film.

7. The detection method according to claim 3, characterized in that, The phase delayer is a quarter-wave plate, and the polarizer is a horizontal linear polarizer.

8. The detection method according to claim 3, characterized in that, The polarization parameters of the light emitted from the optical composite film are obtained based on the light intensity of the light emitted from the polarizer measured by the detection module, specifically including: The intensity of the light emitted from the polarizer is obtained when the angle between the fast axis of the phase delay element and the horizontal direction is α, where α = ωt, and t is the rotation time of the phase delay element; Based on the intensity of the light emitted from the polarizer, the Stokes vector of the light emitted from the optical composite film is obtained; The polarization parameters of the emitted light from the optical composite film are obtained based on the Stokes vector of the emitted light.

9. The detection method according to claim 8, characterized in that, Obtaining the Stokes vector of the light emitted from the optical composite film based on the intensity of the light emitted from the polarizer specifically includes: A model is established to determine the relationship between the intensity of the light emitted from the polarizer and the Stokes vector of the light emitted from the optical composite film. Perform a Fourier transform on the relationship model and obtain the Fourier transform coefficients based on the intensity of the light emitted from the polarizer; The Stokes vector of the emitted light from the optical composite film is obtained based on the Fourier transform coefficients.

10. The detection method according to claim 9, characterized in that, The model for obtaining the relationship between the intensity of the light emitted from the polarizer and the Stokes vector of the light emitted from the optical composite film specifically includes: Let Sm be the Stokes vector of the light emitted from the optical composite film; Based on the Stokes vector Sm, obtain the Stokes vector of the emitted light from the phase delay element. ; According to the Stokes vector Obtain the Stokes vector Sout of the light emitted from the polarizer; Based on the Stokes vector Sout, a relationship model is obtained between the intensity of the polarizer's emitted light and the Stokes vector of the optical composite film's emitted light.

11. The detection method according to claim 10, characterized in that, Based on the Stokes vector Sm, obtain the Stokes vector of the emitted light from the phase delay element. Specifically, it includes: Based on the Stokes vector Sm and the Mueller matrix of the phase retardation element with an angle α between the fast axis and the horizontal direction, the Stokes vector of the emitted light from the phase retardation element is obtained. .

12. The detection method according to claim 10, characterized in that, According to the Stokes vector Obtaining the Stokes vector Sout of the polarizer-emitted light specifically includes: According to the Stokes vector And the Mueller matrix of the polarizer, to obtain the Stokes vector Sout of the polarizer's outgoing light.

13. The detection method according to claim 3, characterized in that, The phase delay element rotates at an angular frequency ω, specifically including: The phase delay element is driven by a stepper motor to rotate at an angular frequency ω, where the number of steps of the stepper motor is n, the step size is aj, and α=ωt=n×aj.

14. A system for detecting the relative angle of optical composite films, characterized in that, The optical composite film relative angle detection system performs the optical composite film relative angle detection method as described in any one of claims 1-13; The detection system includes: a light source assembly and a detection assembly; The light source assembly is used to emit linearly polarized light with multiple fields of view; The detection component is used to detect the relative angle between the optical composite film under test; When the optical composite film to be tested is placed between the light source assembly and the detection assembly, the optical composite film and the detection assembly are arranged along the same optical axis.

15. The detection system according to claim 14, characterized in that, The detection assembly includes: a phase delay element, a polarizer, and a detection module, wherein the phase delay element rotates at an angular frequency ω; When the optical composite film to be tested is placed between the light source assembly and the phase delay element, the optical composite film, the phase delay element, the polarizer, and the detection module are arranged sequentially along the same optical axis.

16. The detection system according to claim 14, characterized in that, The detection components include: a polarizer and an optical power meter; When the optical composite film to be tested is placed between the light source assembly and the analyzer, the optical composite film, the analyzer, and the optical power meter are arranged sequentially along the same optical axis.

17. The detection system according to claim 14, characterized in that, The light source assembly includes: a light source, a fast reflector, a lens group, and a polarizer, wherein the lens group includes at least one lens; The light emitted from the light source passes sequentially through the fast reflector, the lens group, and the polarizer before being projected onto the optical composite film under test.

18. The detection system according to claim 15, characterized in that, It also includes a stepper motor that drives the phase delay element to rotate at an angular frequency ω.

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