A method and device for detecting a polarization composite sheet

Abstract

The present invention discloses a method for detecting a polarization composite sheet, comprising the following steps: measuring the initial light intensity I of the light emitted by a light source through a spectrometer in ; flattening and fixing the polarization composite sheet to be measured through a sample stage, the polarization composite sheet comprising a first film and a second film, the first film comprising a quarter-wave plate, and the second film comprising a linear polarizer or a combination of a linear polarizer and a polarization beam splitter; adjusting the relative angle between the polarization light detection sheet and the polarization composite sheet, and continuously collecting the transmitted light intensity I out ; selecting I out and I μ from the transmitted light intensity I μ+π / 2 , calculating the sum of the orthogonal light intensities I sum = I μ + I μ+π / 2 , and then calculating at least one of the phase delay amount δ of the quarter-wave plate, the transmittance of the polarization composite sheet, and the angle between the light transmission directions of the first film and the second film through the relational expressions of I sum and I out . The above detection method can quickly detect the quality of the polarization composite sheet. The present invention also discloses a device for implementing the above detection method.

Description

Technical Field

[0001] The present invention relates to a method for detecting a polarization composite sheet, and also relates to a device for implementing the above detection method. Background Art

[0002] Polarization composite films are often required in the imaging display optical path, such as the Pancake optical path (ultra-short focal length optical folding optical path) of a typical virtual reality near-eye display system and the birdbath optical path of an augmented reality near-eye display system. If the light emitted from the light-emitting surface of the display is non-circularly polarized light, two types of polarization composite sheets are required, as shown in FIGS. 1(a) and 1(b) respectively. If the light emitted from the light-emitting surface of the display is circularly polarized light, only the polarization composite sheet shown in FIG. 1(a) is required.

[0003] The first type of polarization composite sheet shown in FIG. 1(a) is, from left to right, a linear polarizer (Polarizer, POL), a polarization beam splitter (Polarizing Beam Spliter, PBS), a quarter-wave plate (Quarter-Wave Plate, QWP), and an anti-reflection film (Anti-Reflector, AR); the second type of polarization composite sheet shown in FIG. 1(b) is, from left to right, an anti-reflection film (Anti-Reflector, AR), a quarter-wave plate (Quarter-Wave Plate, QWP), and a linear polarizer (Polarizer, POL); among them, the anti-reflection film (Anti-Reflector, AR) is to reduce the surface reflection of the film and does not affect the polarization state of the transmitted light.

[0004] The film combinations included in these polarization composite sheets often cannot be simply bonded together, and there are special requirements for the relative angles between the light transmission directions of the POL, PBS, and QWP films. For the polarization composite sheet shown in FIG. 1(a), the light transmission direction of the POL should coincide with the light transmission direction of the PBS as much as possible, and the angle formed between the light transmission direction of the PBS and the light transmission direction of the QWP should be as close to 45° as possible. For the polarization composite sheet shown in FIG. 1(b), the angle formed between the light transmission direction of the QWP and the light transmission direction of the POL should be as close to 45° as possible.

[0005] Currently, there are no devices and methods in the prior art for detecting the quality of polarization composite films. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for detecting a polarization composite sheet.

[0007] Another technical problem to be solved by the present invention is to provide a device for detecting a polarization composite sheet.

[0008] To achieve the above technical objectives, the present invention adopts the following technical solutions:

[0009] A method for detecting a polarization composite sheet, comprising the following steps:

[0010] S100, measuring the initial light intensity I of the light emitted by the light source when no polarization composite sheet is placed on the sample stage through a spectrometer in ;

[0011] S102, flattening and fixing the polarization composite sheet to be measured through the sample stage; the polarization composite sheet includes a first film and a second film, the first film is closer to the spectrometer than the second film, the first film includes a quarter-wave plate, the second film includes a linear polarizer, or the second film includes a combination of a linear polarizer and a polarization beam splitter;

[0012] S104, adjusting the relative angle between the polarization light detection sheet and the polarization composite sheet, and continuously collecting the transmitted light intensity I passing through the polarization composite sheet out ;

[0013] S106, using the Jones matrices of the polarization light detection sheet, the first film and the second film, establishing a relational expression between the transmitted light intensity I out and the initial light intensity I in :

[0014] I out =I in τ2τf(δ,μ,β,α,γ);

[0015] where τ2 and τ are the transmittances of the polarization light detection sheet and the polarization composite sheet respectively, δ is the phase retardation amount of the quarter-wave plate, α is the included angle between the light transmission direction of the linear polarizer and the OX axis in the world coordinate system, β is the angle between the light transmission directions of the first film and the second film, μ is the included angle between the light transmission directions of the polarization light detection sheet and the second film, and γ is the included angle between the light transmission directions of the linear polarizer and the polarization beam splitter in the second film;

[0016] S108, arbitrarily selecting two orthogonal light intensities I out and I μ from the transmitted light intensity I μ+π / 2 , calculating the sum of the orthogonal light intensities I sum =I μ +I μ+π / 2 ;

[0017] S110, calculating at least one of the phase retardation amount δ of the quarter-wave plate, the transmittance τ of the polarization composite sheet, and the angle β between the light transmission directions of the first film and the second film through the relational expression of I sum and I out .

[0018] Preferably, in step S106, when the second diaphragm includes a combination of a polarization beam splitter and a linear polarizer, and the polarization beam splitter is disposed between the quarter-wave plate and the linear polarizer, the following relationship is established:

[0019]

[0020] where τ0, τ1, τ q are the transmittances of the linear polarizer, the polarization beam splitter, and the quarter-wave plate diaphragm, respectively.

[0021] Preferably, in step S106, when the second diaphragm contains only the linear polarizer, the following relationship is established:

[0022]

[0023] where τ0, τ1, τ q are the transmittances of the linear polarizer, the polarization beam splitter, and the quarter-wave plate diaphragm, respectively; let γ = 0°, τ1 = 1, and simplify the relationship between the transmitted light intensity I out and the initial light intensity I in therebetween.

[0024] Preferably, the angle between the light transmission directions of the first diaphragm and the second diaphragm refers to the included angle between the light transmission direction of the quarter-wave plate and the light transmission direction of the diaphragm adjacent to the quarter-wave plate in the second diaphragm.

[0025] Preferably, step S108 further includes the following steps: the two orthogonal light intensities are respectively the maximum value I out of the transmitted light intensity I max and the minimum value I min , calculate I sum = I max + I min .

[0026] Preferably, step S110 further includes the following steps:

[0027] When the polarization composite sheet includes a linear polarizer, a polarization beam splitter, and a quarter-wave plate, calculate the included angle γ between the polarization beam splitter and the linear polarizer according to the following formula:

[0028]

[0029] Preferably, step S110 further includes the following steps:

[0030] Let α = 0, and by stacking the single-layer diaphragms in the composite polarizer layer by layer, record multiple I sum, calculate the product of the transmittances τ2 and τ, where τ = τ0τ1τ q , then, calculate the angle γ between the polarization beam splitter and the linear polarizer.

[0031] Preferably, step S110 further includes the following steps:

[0032] Calculate the phase retardation δ of the quarter-wave plate and the angle β between the fast axis direction of the quarter-wave plate and the light transmission direction of the second diaphragm according to the following formula:

[0033]

[0034]

[0035]

[0036] A device for detecting a polarization composite sheet, comprising a light source, a sample stage, a polarization light detection sheet, and a spectrometer arranged in sequence, wherein,

[0037] The light source is used to emit light towards the spectrometer;

[0038] The sample stage is used to carry the polarization composite sheet to be detected and allow the light to pass through the center of the sample stage; the polarization composite sheet includes a first diaphragm and a second diaphragm, the first diaphragm is closer to the spectrometer than the second diaphragm, the first diaphragm includes a quarter-wave plate, the second diaphragm includes a linear polarizer, or the second diaphragm includes a combination of a polarization beam splitter and a linear polarizer;

[0039] The polarization light detection sheet is arranged between the spectrometer and the sample stage and is used for polarization filtering of the light incident on the spectrometer;

[0040] The spectrometer is used to receive the light to collect the initial light intensity of each spectrum and the transmitted light intensity through the sample to be detected;

[0041] The rotation mechanism is used to adjust the relative angle between the polarization light detection sheet and the polarization composite sheet;

[0042] The device further includes a control module, which is used to store the initial light intensity and the transmitted light intensity collected by the spectrometer, and calculate at least one of the phase retardation of the quarter-wave plate, the transmittance of the polarization composite sheet, and the angle between the light transmission directions of the first diaphragm and the second diaphragm in the polarization composite sheet according to the measurement results.

[0043] Preferably, the rotation mechanism is used to rotate the sample stage; or, the rotation mechanism is used to rotate the polarization light detection sheet.

[0044] The method and device for detecting a polarization composite sheet provided by the present invention utilize a spectrometer to detect the initial light intensity I of a light source in and the transmitted light intensity I after passing through the polarization composite sheet out , combine the relative angle between the polarization composite sheet and the polarization detection sheet, establish a relational expression between the transmitted light intensity and the initial light intensity using the Jones matrix, and calculate I sum , and further calculate the phase delay amount δ of the composite sheet QWP (quarter-wave plate), the transmittance τ of the polarization composite sheet, and the angle β between the light transmission directions of the first film and the second film in the polarization composite sheet, etc. The above detection method uses a spectrometer to perform multi-spectral light intensity measurement, can obtain the response of the polarization composite sheet to different wavelengths, and thus obtain various properties of the polarization composite sheet according to different wavelengths, and can quickly detect the quality of the polarization composite sheet. The above detection device has a simple structure and is convenient to operate. Description of the Drawings

[0045] FIG. 1(a) is a schematic diagram of a film combination included in a polarization composite sheet;

[0046] FIG. 1(b) is a schematic diagram of a film combination included in another polarization composite sheet;

[0047] Figure 2 is a schematic diagram of the steps of a method for detecting a polarization composite sheet provided by an embodiment of the present invention;

[0048] Figure 3 is a schematic diagram of the angle symbol convention between each film involved in the detection principle;

[0049] Figure 4 is a schematic diagram of the structure of a device for detecting a polarization composite sheet provided by an embodiment of the present invention;

[0050] Figure 5 is a schematic diagram of the structure of another device for detecting a polarization composite sheet provided by an embodiment of the present invention. Detailed Embodiments

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0052] Taking the polarization composite film shown in FIGS. 1(a) and 1(b) above as a detection schematic, they are respectively film combinations of QWP, POL, and PBS. For the polarization composite film shown in FIG. 1(a), the light transmission direction of POL should coincide with that of PBS as much as possible, and the angle formed between the light transmission direction of PBS and that of QWP should be as close to 45° as possible. For the polarization composite film shown in FIG. 1(b), the angle formed between the light transmission direction of QWP and that of POL should be as close to 45° as possible. In order to detect whether the angles between the light transmission directions of the film layers in the polarization composite film meet the requirements, corresponding detection methods and equipment are needed. Since a polarization light detection film, which is essentially a linear polarizer, i.e., POL, is required in the detection process of the composite polarizer. In the angle model of the polarization composite film measurement system below, in order to distinguish POL as the polarization light detection film from POL in the polarization composite film, the polarization light detection film is defined as the pre-spectrometer POL, and each film layer in the polarization composite film is defined as the composite film QWP, the composite film PBS, and the composite film POL.

[0053] As Figure 2 shown, the present invention provides a method for detecting a polarization composite film, comprising the following steps:

[0054] S100, measuring the initial light intensity I of the light emitted by the light source when no polarization composite film is placed on the sample stage through a spectrometer in .

[0055] S102, flattening and fixing the polarization composite film to be measured through the sample stage;

[0056] The polarization composite film includes a first film and a second film. In the polarization composite film, the first film is closer to the spectrometer than the second film. The first film includes the composite film QWP, and the second film includes the composite film POL, or the second film includes a combination of the composite film PBS and the composite film POL, wherein the composite film PBS is disposed between the composite film QWP and the composite film POL.

[0057] When the second film includes both the composite film PBS and the composite film POL at the same time, the first film and the second film form the polarization composite film shown in FIG. 1(a); when the second film only includes the composite film POL, the first film and the second film form the polarization composite film shown in FIG. 1(b).

[0058] In the polarization composite film shown in FIG. 1(a), ideally, the light transmission directions of the composite film PBS and the composite film POL coincide, and the angle between the light transmission directions of the composite film PBS and the composite film QWP is equal to the angle between the light transmission directions of the composite film POL and the composite film QWP.

[0059] S104. Adjust the relative angle between the polarized light detection film and the polarization composite film, and continuously collect the transmitted light intensity I passing through the polarization composite film. out ;

[0060] By rotating the polarized light detection film or the polarization composite film, the relative angle between the polarized light detection film and the polarization composite film can be adjusted, and both adjustment methods can be achieved. In actual tests, it is preferred to rotate the sample stage, that is, to change the overall angle of the polarization composite film, because the spectrometer and the spectrometer collimating lens have a certain polarization selectivity, and changing the angle between the polarized light detection film (also called the spectrometer front POL) and the spectrometer is likely to introduce errors.

[0061] By rotating the polarized light detection film or the polarization composite film, the relative rotation of the polarized light detection film and the polarization composite film is realized, the rotation angle of the polarized light detection film or the polarization composite film is recorded, and at the same time the transmitted light intensity I is recorded. out , a series of corresponding transmitted light intensities and the rotation angles of the polarized light detection film (or the polarization composite film) are obtained. At this time, the change in the reading of the sample stage can be equivalent to the change in the relative angle between the polarized light detection film and the polarization composite film, and the reading θ of the sample stage is recorded to form an I out -θ curve.

[0062] S106. Using the Jones matrices of the polarized light detection film, the first film and the second film, establish a relationship between the transmitted light intensity I out and the initial light intensity I in :

[0063] I out = I in τ2τf(δ, μ, β, α, γ); (1)

[0064] Among them, τ2 and τ are the transmittances of the polarized light detection film and the polarization composite film respectively, δ is the phase delay of the quarter-wave plate, α is the angle between the transmission direction of the linear polarizer and the OX axis in the world coordinate system, β is the angle between the transmission directions of the first film and the second film, μ is the angle between the transmission directions of the polarized light detection film and the second film, and γ is the angle between the transmission directions of the linear polarizer and the polarization beam splitter in the second film.

[0065] The relationship between the transmitted light intensity I out and the initial light intensity I in can be seen in the detailed derivation process below.

[0066] S108. Arbitrarily select two orthogonal light intensities I out and I μ from the transmitted light intensity I μ+π / 2 , calculate the sum of the orthogonal light intensities I sum = I μ + I μ+π / 2; (2)

[0067] When the film near the first film QWP in the second film is the composite film PBS, μ is the angle between the light transmission direction of the front POL and the light transmission direction of the composite film PBS; when the film near the first film QWP in the second film is the composite film POL, μ is the angle between the light transmission direction of the front POL and the light transmission direction of the composite film POL.

[0068] Since the angle between the polarization light detection film and the light transmission direction of the second film needs to be obtained after calculation during the measurement process. Considering the particularity of polarized light, here, the rotation angle θ of the polarization light detection film or the polarization composite film can be arbitrarily selected, the transmitted light intensity is recorded, and the light intensity orthogonal to it is recorded, and the above two values are used as I μ and I μ+π / 2 , calculate I sum . Preferably, the maximum value I out of the transmitted light intensity I can also be selected from the I max curve and the minimum value I min as two orthogonal light intensities, calculate I sum =I max +I min , μ max and μ min are the μ values corresponding to the maximum value I max and the minimum value I min of the transmitted light intensity respectively, and μ max and μ min differ by π / 2.

[0069] S100, through the relationship formula of I sum , I out , calculate at least one of the phase delay amount δ of the composite film QWP, the transmittance τ of the polarization composite film, and the angle β between the light transmission directions of the first film and the second film in the polarization composite film. Wherein, the angle between the light transmission directions of the first film and the second film is defined as the included angle between the light transmission direction of the composite film QWP and the light transmission direction of the film adjacent to the composite film QWP in the second film.

[0070] The following combines Figure 3 The angles between the respective films shown, and describes the test process of the polarization composite film, especially the specific implementation process of steps S106 to S110.

[0071] As Figure 3 shown, taking the polarization composite film including the composite film QWP, the composite film PBS, and the composite film POL as an example, the included angles between the respective films and symbols such as the transmittance are agreed, and the Jones matrix thereof is obtained as follows:

[0072] [1] Agree on the world coordinate system OXY;

[0073] [2] The included angle between the transmission axis of the composite sheet POL and the OX axis is α, its transmittance is τ0, and it is considered that its extinction ratio is in an ideal state approximately equal to infinity. Then the Jones matrix obtained is:

[0074]

[0075] [3] The composite sheet PBS has two transmission axes, which are the transmission axes of the s-light and p-light respectively, and the two are orthogonal. Here, it is agreed that the polarization state of the light transmitted through the composite sheet POL is s. The included angle between the s-light transmission axis of the composite sheet PBS and the composite sheet POL is γ, then its included angle with the OX axis is α + γ, its transmittance is τ1, and the extinction ratio is in an ideal state approximately equal to infinity. Then the Jones matrix obtained is:

[0076]

[0077] [4] The included angle between the fast axis direction of the composite sheet QWP and the composite sheet PBS is β, its phase retardation is δ, and the transmittance is τ q , then the Jones propagation matrix obtained is:

[0078]

[0079] [5] The included angle between the transmission axis direction of the pre-spectrometer POL and the OX axis is θ, the included angle with the composite sheet PBS is μ, and the transmittance is τ2. Similarly, considering the extinction ratio to be approximately infinity, then its Jones matrix is:

[0080]

[0081] [6] The intensity of the incident light source is I in , then the Jones vector of the incident light is:

[0082]

[0083] It should be noted that in the polarization composite sheet during actual measurement, the magnitude of α is arbitrary, and it is only related to the direction of the agreed world coordinate system; the angle of β fluctuates around 45°, and through the attachment process control of the polarization composite sheet, the fluctuation range of β will not exceed ±1°, and the angle of γ will not exceed 1° either. δ fluctuates around 90°, and δ presents different values with the wavelength; for the polarization composite sheet sample to be measured placed on the sample stage, β, γ, and δ should be fixed values; during the measurement process, only θ will change with the relative rotation of the pre-spectrometer POL and the polarization composite sheet, thereby affecting the change of μ. Among them, θ = α + γ + μ. (8)

[0084] Next, taking the example of changing the relative angle between the polarization light detection sheet and the polarization composite sheet by rotating the sample stage to achieve measurement, an introduction is given.

[0085] Multiply each Jones matrix successively with the incident light Jones vector E in to obtain the light Jones vector E out received by the spectrometer. Since the spectrometer can only obtain the light intensity, conjugate multiplication is then performed to obtain the final light intensity I out :

[0086] E out = J p2 J qwp J p1 J p0 E in (9)

[0087]

[0088] It can be seen from the above formula that I out is related to the above-mentioned various angles, phase delay amounts, transmittances, and incident light intensity.

[0089] When the film under test is in an ideal state, that is, β = 45° (the included angle between the composite QWP and the composite PBS is 45°, and the transmission directions of the composite PBS and the composite POL coincide), δ = 90° (QWP brings a perfect quarter-wave phase delay), substituting into the above formula (10), it can be seen that at this time, the magnitude of I out is independent of μ, that is, no matter how the pre-spectrometer POL rotates, the light intensity received by the spectrometer remains unchanged.

[0090] The following introduces step S110, specifically the process of measuring the phase delay amount δ of the composite QWP, the transmittance τ of the polarization composite film, and the angle β between the transmission directions of the first film and the second film in the polarization composite film.

[0091] S111, the measurement process of the included angle γ between the composite POL and the composite PBS:

[0092] When rotating the pre-spectrometer POL, θ and μ change. Due to the special properties of the polarization state, it can be expected that the light intensity corresponding to a certain θ and μ is recorded as I μ . When μ becomes μ + π / 2, the corresponding light intensity at this time is recorded as I μ+π / 2 . Through mathematical derivation, we get:

[0093]

[0094] It can be seen that: the sum of the orthogonal light intensities I sum is independent of θ, μ, β, and δ. I in can be measured. If τ0τ1τ2τ q, and it is agreed that the OX axis of the world coordinate system coincides with the light transmission direction of the composite sheet POL (i.e., α = 0), and then the value of γ can be obtained.

[0095] For the transmittances τ0, τ1, τ2, τ q , they can be obtained by measurement. By placing the film sheets in the composite polarizer layer by layer and recording multiple I sum , the transmittances τ0, τ1, τ q and τ2 can be calculated through Equation (11), and then τ0τ1τ2τ q is calculated, and then γ is obtained. The transmittance τ of the polarization composite sheet is defined as the product of τ0, τ1, τ q . Through the above measurement process, the transmittance τ of the polarization composite sheet can be calculated, τ = τ0τ1τ q .

[0096] The measurement process of S112, the included angle β between the light transmission direction of the composite sheet POL and the light transmission direction of the composite sheet QWP, and the phase delay δ of the composite sheet QWP:

[0097] Derive I out with respect to μ and set it to 0, and it is obtained that μ satisfies at this time:

[0098]

[0099] When μ satisfies the above formula, I out reaches the maximum or minimum value, and the μ corresponding to the maximum and minimum values differ by π / 2. Substitute the μ and μ + π / 2 that satisfy the above formula into the above formula, and the expressions of I max and I min can be obtained.

[0100] When testing, rotate the sample stage (equivalent to rotating the pre-POL of the spectrometer), and synchronously record the spectrometer readings. There are:

[0101]

[0102] When the light intensity reaches the maximum I max , record the rotation stage angle as μ max at this time; continue to rotate the sample stage by 90° exactly, and the light intensity should be the minimum at this time, recorded as I min . According to the above processes, there are the following relational expressions:

[0103]

[0104]

[0105] The above derivation is for the numerical model of a single wavelength, and each wavelength also conforms to this model under multiple wavelengths.

[0106] For a certain measured sample, the magnitude of β is the angle between the composite film QWP and the composite film POL or the composite film PBS, and the measured value of β does not change with the wavelength; the phase retardation amount δ of the composite film QWP varies with different wavelengths. Regarding this property, by using a spectrometer to perform multi-spectral light intensity measurement, the response of the polarization composite film to different wavelengths can be obtained, thereby obtaining various properties of the polarization composite film according to different wavelengths.

[0107] According to Equations (13), (14), and (15), the process of calculating β and δ is as follows:

[0108] Coincide the world coordinate system OXY with the XY axes of the sample stage. At this time, the angle reading of the sample stage is the magnitude of θ. As previously described, it is agreed that the OX axis of the world coordinate system OXY coincides with the light transmission direction of the composite film POL (i.e., α = 0), and the specific value of γ has been obtained. According to the relationship θ = α + γ + μ, the magnitude of μ can be obtained.

[0109] Rotate the sample stage, record the angle reading and the spectrometer light intensity reading, and obtain multiple sets of μ and I out values. The following is an example: Record a set of data every 0.5°, collect 720 sets of data within the range of 360°, and simultaneously obtain 720 I sum magnitudes; theoretically, these I sum values should be equal, but there will always be errors introduced in practice. It is preferable to take the average value of I sum to reduce the error.

[0110] As mentioned above, the β of a single polarization composite film does not change with the wavelength, while δ varies with the wavelength. A spectrometer can be used to collect the transmitted intensity within a multi-spectral range. For example, the sampling wavelength range is 300 - 750 nm, and the sampling accuracy is 0.1 nm, that is, 4500 data can be obtained in a single sampling. According to the expression of I out / I sum and the actual value, 720 sets of collected data are used to establish 720 * 4500 = 3240000 equations, and by solving the system of equations, the values of β and δ are calculated.

[0111] In the above detection method, taking the polarization composite film that simultaneously includes QWP, PBS, and POL as an example, the detection process of the polarization composite film is introduced. When the polarization composite film only contains QWP and POL, let γ = 0°, τ1 = 1, the above calculation relationships can be simplified, and various parameters such as the angle of the light transmission directions of the first film and the second film in the polarization composite film, the phase retardation amount of the quarter-wave plate, and the transmittance of the polarization composite film can also be obtained. This will not be elaborated here.

[0112] Meanwhile, the present invention provides a device for implementing the above detection method. AsFigure 4 and Figure 5 are two different detection devices, where the rotating mechanism realizes the relative rotation of the polarization detection sheet and the polarization composite sheet through two different rotation methods.

[0113] Specifically, as Figure 4 and Figure 5 shown, a device for detecting a polarization composite sheet provided by an embodiment of the present invention includes a light source 10, a sample stage 20, a polarization light detection sheet 30, and a spectrometer 40 arranged in sequence. Among them, the light source 10 is used to emit light in the direction of the spectrometer 40; the sample stage 20 is used to carry the polarization composite sheet 50 to be detected and allow the light to pass through the center of the sample stage 20; the polarization light detection sheet 30 is arranged between the spectrometer 40 and the sample stage 20 and is used to perform polarization filtering on the light incident on the spectrometer 40; the spectrometer 40 is used to receive the light to collect the initial light intensity I in and the transmitted light intensity I out .

[0114] The detection device further includes a control module and a rotating mechanism. Among them, the control module is respectively connected to the light source 10, the rotating mechanism, and the spectrometer 40 and is used to realize the control of each part in the detection device. The rotating mechanism is used to adjust the relative angle between the polarization light detection sheet 30 and the polarization composite sheet 50. As Figure 4 shown, the rotating mechanism is a film-carrying rotating stage, and the rotating mechanism is connected to or integrated with the sample stage 20 and is used to carry and rotate the polarization composite sheet 50 to be measured. As Figure 5 shown, the rotating mechanism 60 is a measurement rotating stage and is used to carry and rotate the polarization detection sheet 30 (i.e., the POL in front of the spectrometer).

[0115] The control module is further used to store the initial light intensity I in and the transmitted light intensity I out collected by the spectrometer 40, and calculate at least one of the phase delay amount of the quarter-wave plate, the transmittance of the polarization composite sheet, and the angle between the light transmission directions of the first film and the second film in the polarization composite sheet according to the measurement results. The data processing process of the relative angle between the light transmission directions of the polarization light detection sheet and the polarization composite sheet, the angle between the light transmission directions of the first film layer and the second film layer in the polarization composite sheet, the initial light intensity I in and the transmitted light intensity I out is referred to the above, and will not be elaborated here.

[0116] Preferably, a negative pressure generator is further included in the detection device. The sample stage 20 is provided with air holes. The negative pressure generator is connected to the air holes of the sample stage 20 through an air pipe, and is used to form a negative pressure between the polarization composite sheet 50 and the sample stage 20, so that the polarization composite sheet 50 is adsorbed on the sample stage.

[0117] In summary, the present invention provides a method and a device for detecting a polarization composite sheet. The initial light intensity of a light source and the transmitted light intensity after passing through the polarization composite sheet are detected by a spectrometer. Combining the relative angle between the polarization composite sheet and the polarization detection sheet, a relational expression between the transmitted light intensity and the initial light intensity is established by using the Jones matrix, and at least one of the phase delay amount δ of the quarter-wave plate, the transmittance of the polarization composite sheet, and the angle between the light transmission directions of the first film and the second film in the polarization composite sheet is calculated. In the above detection method, a spectrometer is used for multi-spectral light intensity measurement, and the response of the polarization composite sheet to different wavelengths can be obtained, so that the properties of the polarization composite sheet according to different wavelengths can be obtained, and the quality of the polarization composite sheet can be quickly detected. The above detection device has a simple structure and is convenient to operate.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting a polarization composite sheet, characterized in that, The method includes the following steps: S100, measuring the initial light intensity I of the light emitted by the light source when no polarization composite sheet is placed on the sample stage through a spectrometer in ; S102, flattening and fixing the polarization composite sheet to be measured through a sample stage; the polarization composite sheet includes a first film and a second film, the first film is closer to the spectrometer than the second film, the first film includes a quarter-wave plate, and the second film includes a linear polarizer, or the second film includes a combination of a linear polarizer and a polarization beam splitter; S104. Adjust the relative angle between the polarized light detection film and the polarization composite film, and continuously collect the transmitted light intensity I passing through the polarization composite film out ; S106. Establish a relational expression between the transmitted light intensity I out out and the initial light intensity I in in by using the Jones matrices of the polarization light detection sheet, the first diaphragm, and the second diaphragm: I out = I in τ2τf(δ, μ, β, α, γ); where τ2 and τ are the transmittances of the polarization light detection sheet and the polarization composite sheet respectively, δ is the phase retardation amount of the quarter-wave plate, α is the angle between the light transmission direction of the linear polarizer and the OX axis in the world coordinate system, β is the angle between the light transmission directions of the first film and the second film, μ is the angle between the light transmission directions of the polarization light detection sheet and the second film, and γ is the angle between the light transmission directions of the linear polarizer and the polarization beam splitter in the second film; When the second diaphragm includes a combination of a polarization beam splitter and a linear polarizer, and the polarization beam splitter is disposed between the quarter-wave plate and the linear polarizer, I out and the initial light intensity I in The relational expression between them is: where τ = τ0τ1τ q , τ0, τ1, and τ q are the transmittances of the linear polarizer, the polarization beam splitter, and the quarter-wave plate film, respectively; S108, from the transmitted light intensity I out arbitrarily select two orthogonal light intensities I μ and I μ+π / 2 , calculate the sum of the orthogonal light intensities I sum = I μ + I μ+π / 2 ; S110, calculate at least one of the phase delay δ of the quarter-wave plate, the transmittance τ of the polarization composite sheet, and the angle β between the light transmission directions of the first diaphragm and the second diaphragm through the relationship of I sum、 I out ​ 2. The method for detecting a polarization composite sheet according to claim 1, characterized in that: In step S106, when only the linear polarizer is included in the second diaphragm, let γ = 0°, τ1 = 1, and simplify the relationship between the transmitted light intensity I out and the initial light intensity I in between the relationships.

3. The method for detecting a polarization composite sheet according to claim 1, characterized in that: The angle between the light transmission directions of the first film and the second film refers to the angle between the light transmission direction of the quarter-wave plate and the light transmission direction of the film adjacent to the quarter-wave plate in the second film.

4. The method for detecting a polarization composite sheet according to claim 1, characterized in that In step S108, the following steps are further included: The two orthogonal light intensities are respectively the maximum value I of the transmitted light intensity I max and the minimum value I min . Calculate I sum = I max + I min .

5. The method for detecting a polarization composite sheet according to claim 1, wherein In step S110, the following steps are further included: When the polarization composite sheet includes a linear polarizer, a polarization beam splitter and a quarter-wave plate, calculate the angle γ between the polarization beam splitter and the linear polarizer according to the following formula:

6. The method for detecting a polarization composite sheet according to claim 5, wherein In step S110, the following steps are further included: Let α = 0, and by placing the single-layer films in the composite polarizer layer by layer, record multiple I sum , calculate the transmittances τ0, τ1, τ q and τ2, and calculate the product of τ2 and τ, where τ = τ0τ1τ q , then calculate the angle γ between the polarization beam splitter and the linear polarizer.

7. The method for detecting a polarization composite sheet according to claim 1, wherein In step S110, the following steps are further included: Calculate the phase retardation amount δ of the quarter-wave plate and the angle β between the fast axis direction of the quarter-wave plate and the light transmission direction of the second film according to the following formula:

8. An apparatus for detecting a polarization composite sheet, for implementing the method according to any one of claims 1-7, characterized in that It includes a light source, a sample stage, a polarization light detection sheet, and a spectrometer arranged in sequence, where The light source is used to emit light towards the spectrometer direction; The sample stage is used to carry the polarization composite sheet to be detected and allow the light to pass through the center of the sample stage; the polarization composite sheet includes a first film and a second film, the first film is closer to the spectrometer than the second film, the first film includes a quarter-wave plate, and the second film includes a linear polarizer, or the second film includes a combination of a polarization beam splitter and a linear polarizer; The polarization light detection sheet is arranged between the spectrometer and the sample stage and is used for polarization filtering of the light incident on the spectrometer; The spectrometer is used to receive the light to collect the initial light intensity of each spectrum and the transmitted light intensity passing through the sample to be detected; The device further includes a rotation mechanism for adjusting the relative angle between the polarization light detection sheet and the polarization composite sheet; The device further includes a control module for storing the initial light intensity and the transmitted light intensity collected by the spectrometer and calculating at least one of the phase retardation amount of the quarter-wave plate, the transmittance of the polarization composite sheet, and the angle between the light transmission directions of the first film and the second film in the polarization composite sheet according to the measurement result.

9. The device for detecting a polarization composite sheet according to claim 8, wherein: The rotation mechanism is used to rotate the sample stage; alternatively, the rotation mechanism is used to rotate the polarized light detection sheet.

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