TWI808798B - Optical detecting system and operating method thereof - Google Patents

Abstract

An optical detecting system is configured to detect a to-be tested device having a first linear polarizer and a quarter-wave plate. The optical detecting system includes a light source, a polarization adjustment assembly, and a detecting unit. The light source has a light emitting surface and is configured to emit light. The polarization adjustment assembly faces the light emitting surface of the light source. The polarization adjustment assembly is configured to convert the light to linearly polarized light. The first linear polarizer is located between the polarization adjustment assembly and the quarter-wave plate. The to-be tested device is configured to convert the linearly polarized light to circularly polarized light. The detecting unit is located on a side of the to-be tested device facing away from the polarization adjustment assembly. The detecting unit is configured to calculate an including angle between an absorption axis of the first linear polarizer and a fast axis of the quarter-wave plate of the to-be tested device based on the circularly polarized light.

Description

Optical detection system and method of operation thereof

The present disclosure relates to an optical detection system and an operation method of the optical detection system.

Generally speaking, the optical components in virtual reality (VR) products are mainly composed of linear polarizers and quarter-wave plates, and detection equipment is used to determine whether the linear polarization directionality of the linear polarizers is offset from the circular polarization directionality of the quarter-wave plates. However, the detection process of existing detection equipment needs to input the material-related parameters of the quarter-wave plate and linear polarizer, such as thickness, refractive index, and extinction coefficient, which increases the overall operation time and operational complexity.

One technical aspect of the present disclosure is an optical detection system.

According to an embodiment of the present disclosure, an optical detection system is configured to detect a device under test having a first linear polarizer and a quarter-wave plate. The optical detection system includes: a light source, a polarization adjustment component and a detection unit. The light source has a light-emitting surface and is configured to emit light. The polarization adjusting component faces the light emitting surface of the light source. The polarizer is configured to convert the light to linearly polarized light. The first linear polarizer is located between the polarization adjustment component and the quarter wave plate. The DUT is configured to convert linearly polarized light to circularly polarized light. The detection unit is located on the side of the element under test facing away from the polarization adjustment component. The detection unit is configured to calculate the phase difference angle between the absorption axis of the first linear polarizer of the device under test and the fast axis of the quarter-wave plate of the device under test according to the circularly polarized light.

In an embodiment of the present disclosure, the above-mentioned polarization adjusting component includes a depolarizer. The depolarizer is located between the light source and the first linear polarizer of the DUT. Depolarizers are configured to convert light to unpolarized light.

In an embodiment of the present disclosure, the above-mentioned polarization adjusting component further includes a second linear polarizer. The second linear polarizer is located between the depolarizer and the first linear polarizer of the element under test. The second linear polarizer is configured to convert unpolarized light to linearly polarized light.

In an embodiment of the present disclosure, the optical detection system further includes a beam reducer. The beam reducer is located between the DUT and the detection unit.

In an embodiment of the present disclosure, the central wavelength of the quarter-wave plate is the same as the wavelength of the light.

In an embodiment of the present disclosure, the above-mentioned light source is a laser light source.

One technical aspect of the present disclosure is an operation method of an optical detection system.

According to an embodiment of the present disclosure, an operation method of an optical detection system includes: using a light source to transmit light to a polarization adjustment component; using the polarization adjustment component to convert the light into linearly polarized light and sending it to the element under test, wherein the element under test has a first linear polarizer and a quarter-wave plate, and the first linear polarizer is located between the polarization adjustment component and the quarter-wave plate; converting the linearly polarized light into circularly polarized light by the element under test and sending it to the detection unit; The phase difference angle between the fast axes of the quarter-wave plates.

In an embodiment of the present disclosure, the calculation of the phase difference angle based on the circularly polarized light further includes: rotating the DUT to obtain the light intensity and optical rotation intensity of the DUT; and calculating the maximum elliptical polarization rate of the DUT according to the light intensity and the optical rotation intensity.

In an embodiment of the present disclosure, the aforementioned converting the light into linearly polarized light by the polarization adjustment component and emitting it to the device under test further includes: converting the light into non-polarized light by the depolarizer of the polarization adjustment component and emitting it to the second linear polarizer of the polarization adjustment component;

In an embodiment of the present disclosure, the calculation of the phase difference angle based on the circularly polarized light further includes: rotating the second linear polarizer to obtain the light intensity and the optical rotation intensity of the device under test; and calculating the maximum elliptical polarization rate of the device under test according to the light intensity and the optical rotation intensity.

In an embodiment of the present disclosure, the above-mentioned converting the linearly polarized light into circularly polarized light by the device under test and sending it to the detection unit further includes: using a beam reducer to reduce the spot diameter of the circularly polarized light passing through the device under test to between 0.1 mm and 5 mm before sending it to the detection unit.

In the above embodiments of the present disclosure, the detection unit of the optical detection system can calculate the phase difference angle between the absorption axis of the first linear polarizer of the DUT and the fast axis of the quarter-wave plate of the DUT according to the circularly polarized light passing through the DUT. When the phase difference angle is close to 0, the optical detection system can determine that the absorption axis of the first linear polarizer (that is, the direction of linear polarization) and the fast axis of the quarter-wave plate (that is, the direction of circular polarization) of the component under test are not offset, which can ensure that each component under test detected by the optical detection system has the same quality performance. In addition, the detection unit of the optical detection system does not need to input material-related parameters (such as thickness, refractive index, and extinction coefficient) of the component to be tested when detecting the component to be tested, which can save time for the optical detection system to perform detection and reduce overall operational complexity.

The description of the embodiments disclosed below provides many different implementations, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present case. Of course, these examples are only examples and are not intended to be limiting. In addition, the present case may repeat element symbols and/or letters in various instances. This repetition is for the purposes of brevity and clarity and does not in itself dictate a relationship between the various implementations and/or configurations discussed.

Spatially relative terms such as "below," "beneath," "lower," "above," "upper," etc. may be used herein for convenience of description to describe the relationship of one element or feature to another as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in a method of use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

FIG. 1 shows a schematic diagram of an optical detection system 100 in operation according to an embodiment of the present disclosure. The optical detection system 100 is configured to detect the DUT 200 having the first linear polarizer 210 and the quarter wave plate 220 . For example, the device under test 200 can be a lens of virtual reality (VR) glasses, but it is not limited thereto. The optical detection system 100 includes a light source 110 , a polarization adjustment component 120 and a detection unit 130 . The light source 110 of the optical detection system 100 has a light emitting surface 112 and is configured to emit light L. As shown in FIG. In some embodiments, the light source 110 can be a laser light source 110, and the laser light source 110 can emit green laser light with a wavelength of 532 nm and a power of 20 mW. In addition, the central wavelength of the quarter-wave plate 220 of the DUT 200 is the same as the wavelength of the light L. As shown in FIG. For example, when the surface of the device under test 200 is flat, the central wavelength of the quarter-wave plate 220 and the wavelength of the light L of the device under test 200 may be 532 nm, but not limited thereto.

In addition, the polarization adjustment component 120 of the optical detection system 100 faces the light emitting surface 112 of the light source 110 . The polarization adjustment component 120 includes a depolarizer 122 and a second linear polarizer 124 . The depolarizer 122 of the polarization adjusting component 120 is located between the light source 110 and the second linear polarizer 124 . The second linear polarizer 124 of the polarization adjustment component 120 is located between the depolarizer 122 and the first linear polarizer 210 of the DUT 200 . The first linear polarizer 210 of the device under test 200 is located between the second linear polarizer 124 of the polarization adjustment assembly 120 and the quarter wave plate 220 of the device under test 200 . Both the second linear polarizing film 124 and the device under test 200 can be positioned on the rotating system to be rotatable. In some implementations, the detection unit 130 is located on a side of the device under test 200 facing away from the polarization adjustment assembly 120 . That is to say, the detection unit 130 and the polarization adjustment assembly 120 are located on opposite sides of the DUT 200 , and the first linear polarizer 210 of the DUT 200 is closer to the polarization adjustment assembly 120 than the quarter-wave plate 220 , and the quarter-wave plate 220 of the DUT 200 is closer to the detection unit 130 than the first linear polarizer 210 .

In some embodiments, the device under test 200 may include a substrate 230 . The first linear polarizer 210 and the quarter-wave plate 220 of the device under test 200 are bonded to opposite sides of the substrate 230 , and the material of the substrate 230 may include glass and polymer materials. The detection unit 130 of the optical detection system 100 may include a processor or a chip with a predetermined circuit layout or a built-in application program. The detection unit 130 can calculate the light intensity, circular polarization direction and light rotation intensity received by the device under test 200 to achieve the effect of optical alignment detection of the device under test 200 . For example, the optical detection system 100 can detect whether the device under test 200 has a proper polarization direction and angle. When the user wears the virtual reality glasses to watch the stereoscopic image, the phenomena such as tilting of the penetration axis or cross talk can be reduced.

It should be understood that the connection relationship and functions of the components that have been described will not be repeated, and will be described first. In the following description, the operation method of the optical detection system will be explained.

FIG. 2 shows a flow chart of the operation method of the optical detection system according to an embodiment of the present disclosure. The method of operation of the optical detection system includes the following steps. Firstly, in step S1, the light source emits light to the polarization adjustment component. Then in step S2, the light is converted into linearly polarized light by the polarization adjustment component and emitted to the device under test, wherein the device under test has a first linear polarizer and a quarter wave plate, and the first linear polarizer is located between the polarization adjustment component and the quarter wave plate. Then in step S3, the linearly polarized light is converted into circularly polarized light by the device under test and sent to the detection unit. Then in step S4, the phase difference angle between the absorption axis of the first linear polarizer of the device under test and the fast axis of the quarter-wave plate of the device under test is calculated according to the circularly polarized light. In the following description, the above-mentioned steps will be described in detail.

Referring to FIG. 1 and FIG. 3 at the same time, firstly, the light source 110 can emit light L to the polarization adjustment component 120 . For example, the light source 110 can be a laser light source 110 , and the light source 110 can emit green laser light with a wavelength of 532 nm to the depolarizer 122 of the polarization adjustment component 120 . In some implementations, the depolarizer 122 of the polarization adjustment component 120 can convert the received light L into unpolarized light P1 and emit the unpolarized light P1 to the second linear polarizer 124 of the polarization adjustment component 120 . The second linear polarizer 124 of the polarization adjusting component 120 can convert the received unpolarized light P1 into linearly polarized light P2 and transmit the linearly polarized light P2 to the DUT 200 .

In some embodiments, the device under test 200 has a first linear polarizer 210 , a quarter wave plate 220 and a substrate 230 located between the first linear polarizer 210 and the quarter wave plate 220 . For example, the device under test 200 can be a lens of virtual reality (VR) glasses, but it is not limited thereto. In some embodiments, the central wavelength of the quarter-wave plate 220 of the DUT 200 is the same as the wavelength of the light L. For example, the central wavelength of the quarter-wave plate 220 of the device under test 200 and the wavelength of the light L may be 532 nm, but not limited thereto. The device under test 200 can convert the received linearly polarized light P2 into circularly polarized light P3 , and emit the circularly polarized light P3 to the light receiving surface 132 of the detection unit 130 .

In some embodiments, the detection unit 130 may include a processor or a chip with a predetermined circuit layout or built-in application programs. The detection unit 130 can calculate the ellipticity (Ellipticity) of the device under test 200 according to the circularly polarized light P3. In detail, the second linear polarizer 124 of the polarization adjusting component 120 can be rotated by the rotating system or the stage (not shown) carrying the device under test 200 can be rotated by the rotating system to obtain the light intensity and optical rotation intensity of each part of the device under test 200 , and the detection unit 130 can calculate the maximum ellipsoidal polarization rate of the device under test 200 according to the light intensity and optical rotation intensity of the device under test 200 . For example, the detection unit 130 can measure the light intensity and optical rotation intensity every time the second linear polarizer 124 or the stage carrying the device under test 200 rotates 10 degrees, and the detection unit 130 can use the Stokes vector to calculate the elliptical polarization rate of the device under test 200 . The mathematical formula of the elliptic polarization rate can be , where I, Q, U and V are the four parameters of the Stokes vector.

After calculating the maximum ellipsometric rate of the component under test 200, the detection unit 130 can convert the value of the maximum rate of ellipsoidal polarization into the phase difference angle between the absorption axis of the first linear polarizer 210 (see FIG. 3 ) of the component under test 200 and the fast axis of the quarter-wave plate 220 of the component under test 200 (see FIG. 3 ). For example, after subtracting the angle a between the azimuth angle and the fast axis of the quarter-wave plate 220 minus the angle b (negative number) between the azimuth angle and the absorption axis of the first linear polarizer 210, and then subtracting the theoretical value (i.e. 135 degrees), the phase difference angle can be obtained.

Specifically, when the phase difference angle approaches 0, the optical detection system 100 can determine that the absorption axis (ie, the linear polarization direction) of the first linear polarizer 210 and the fast axis (ie, the circular polarization direction) of the quarter-wave plate 220 of the DUT 200 do not deviate, which can ensure that each DUT 200 detected by the optical detection system 100 has the same quality performance. In addition, the detection unit 130 of the optical detection system 100 does not need to input the material-related parameters (such as thickness, refractive index, and extinction coefficient) of the device under test 200 when detecting the device under test 200, which can save the time for the detection of the optical detection system 100 and reduce the complexity of the overall operation.

FIG. 4A to FIG. 7 show the relationship between the phase difference angle and the elliptical polarization ratio according to different embodiments of the present disclosure. Referring to FIG. 1 , FIG. 4A and FIG. 4B , when the surface of the DUT 200 is flat, the reference wavelength of the light L and the center wavelength of the quarter-wave plate 220 may be 532 nm. In Figure 4A and Figure 4B, the horizontal axis is the value of the phase difference (degrees), and the vertical axis is the value of the elliptic polarization rate (maximum 1). The diamond symbols are experimental values at a reference wavelength of 532nm. The measurement line segment 410 and the experimental line segment 420 composed of rhombus symbols show that when the ellipticity (Ellipticity) is larger, the phase difference angle is smaller, which means that the absorption axis (ie, the linear polarization direction) of the first linear polarizer 210 of the device under test 200 and the fast axis (ie, the circular polarization direction) of the quarter wave plate 220 are aligned more accurately. For example, the experimental line segment 420 can be obtained by mathematical simulation software (such as LightTools). In the real measurement line segment 410 and the experimental line segment 420 of the experimental data model, both the ellipsometry and the phase difference angle have a negative correlation characteristic, that is, the larger the elliptic polarization rate is, the smaller the absolute value of the phase difference angle is. In addition, R squared can be calculated by measuring the line segment 410 . R square can also be called the coefficient of determination (Coefficient of determination). When the R square is closer to 1, the explanatory power of the model is higher, and as long as the R square is greater than 0.75, it has the explanatory power of the model. In this embodiment, the R-square of the real measurement line segment 410 may be 0.78.

Referring to FIG. 1, FIG. 5A, FIG. 5B and FIG. 5C, when the surface of the device under test 200 is a curved surface, the reference wavelength of the light L and the center wavelength of the quarter-wave plate 220 can be 589nm. In Fig. 5, the horizontal axis is the numerical value of the phase difference angle, and the vertical axis is the numerical value of the elliptical polarization ratio. According to the measured line segment 510 and the experimental line segment 520, it can be seen that when the ellipticity (Ellipticity) is larger, the angle of difference is smaller, which means that the absorption axis (that is, the direction of linear polarization) of the first linear polarizer 210 of the device under test 200 and the fast axis (that is, the direction of circular polarization) of the quarter-wave plate 220 do not deviate. For example, the experimental line segment 520 can be obtained by mathematical simulation software (such as Zemax). In the actual measurement line segment 510 and the experimental line segment 520 of the experimental data model, both the ellipsometry and the phase difference angle exhibit a characteristic of negative correlation, that is, the larger the ellipsometry, the smaller the absolute value of the phase difference angle. In addition, in this embodiment, the R-square of the real measurement line segment 410 may be 0.94. FIG. 5C shows that even though the measured line segment 510 and the experimental line segment 520 have slight data differences, the elliptical polarization ratio and the phase difference angle of the measured line segment 510 and the experimental line segment 520 still show a negative correlation characteristic.

The experimental line segment 610 in FIG. 6A shows the value change of the phase difference angle between 1 degree and 1.5 degree and the elliptic polarization ratio. The experimental line segment 620 in FIG. 6B shows the value change of the phase difference angle between 1.6 degrees and 5 degrees and the elliptic polarization ratio. Referring to FIG. 1 , FIG. 6A and FIG. 6B , when the surface of the device under test 200 is curved, the reference wavelength of the light L and the center wavelength of the quarter-wave plate 220 may be about 587.6 nm. For example, the experimental line segment 610 and the experimental line segment 620 can be obtained by mathematical simulation software (such as Zemax). In Figure 6A and Figure 6B, the horizontal axis is the value of the angle difference, and the vertical axis is the value of the elliptic polarization. When the angle difference is about 1 degree, it has the maximum ellipticity (Ellipticity), that is, the ellipticity is about 0.966. When the angle difference is about 5 degrees, it has a small ellipticity (Ellipticity), that is, the ellipticity is about 0.84. Both the ellipsoidal polarization in Fig. 6A and Fig. 6B show a negative correlation with the phase difference angle, that is, the larger the ellipsoidal polarization is, the smaller the absolute value of the phase difference is. In addition, in this embodiment, the R square of the experimental line segment 610 and the experimental line segment 620 may be 0.999.

The ideal line segment 710 in FIG. 7 shows the numerical change of the elliptical polarization ratio and phase difference angle of the DUT 200 when the light source 110 has no laser spot. The measurement line segment 720 in FIG. 7 shows the numerical changes of the elliptical polarization ratio and phase difference angle of the DUT 200 when the laser spot of the light source 110 is 3 millimeters (mm). The measurement line segment 730 in FIG. 7 shows the numerical changes of the elliptical polarization ratio and phase difference angle of the DUT 200 when the laser spot of the light source 110 is 5 millimeters (mm). Please refer to Figure 1 and Figure 7, the horizontal axis is the value of the phase difference angle, and the vertical axis is the value of the elliptic polarization. The laser spot size of the light source 110 is 3 millimeters (mm), which corresponds to the 1.5 mm deviation of the light L from the optical axis, and the 5 mm laser spot of the light source 110 corresponds to the 2.5 mm deviation of the light L from the optical axis. For the component under test 200 with a curved surface, the values of the ideal line segment 710 and the measured line segment 720 and 730 with laser spots are slightly different, but the elliptical polarization rate and the phase difference angle still show a negative correlation characteristic, that is, the larger the elliptic polarization rate, the smaller the absolute value of the phase difference angle.

FIG. 8A shows the relationship between angle and light intensity according to an embodiment of the present disclosure. FIG. 8B shows the relationship between angle and ellipticity according to an embodiment of the present disclosure. The horizontal axis of Fig. 8A is the numerical value of the phase difference angle, and the vertical axis is the numerical value of the light intensity. The horizontal axis of Figure 8B is the value of the phase difference angle, and the vertical axis is the value of the elliptic polarization. In some embodiments, the mathematical formula for elliptic polarization can be , where I, Q, U and V are the four parameters of the Stokes vector. For example, when the angle of the measuring line segment 810 is between 130 degrees and 140 degrees, the device under test 200 has the maximum light intensity, that is, has the maximum I parameter and V parameter. When the device under test 200 has the maximum light intensity (ie, has the maximum I parameter and V parameter), the measuring line segment 820 has the maximum elliptical polarization rate of the device under test 200 , that is, the elliptical polarization rate is about 0.99. That is to say, the I parameter and the V parameter of the device under test 200 will affect the value of the elliptic polarization of the device under test 200 .

In the following description, other forms of optical detection systems will be described.

FIG. 9 is a schematic diagram illustrating the operation of an optical detection system 100 a according to another embodiment of the present disclosure. The difference from the embodiment shown in FIG. 1 is that the optical detection system 100 a further includes a beam reducer 140 . The beam reducer 140 is located between the DUT 200 and the detection unit 130 . When the circularly polarized light P3 passes through the device under test 200 with a curved surface, the spot diameter may be enlarged. The beam reducer 140 can reduce the spot diameter of the circularly polarized light P3 passing through the device under test 200 to between 0.1 mm and 5 mm, so that the reduced laser spot of the circularly polarized light P3 can be completely received by the detection unit 130 .

To sum up, the detection unit of the optical detection system can calculate the phase difference angle between the absorption axis of the first linear polarizer of the DUT and the fast axis of the quarter-wave plate of the DUT according to the circularly polarized light passing through the DUT. When the phase difference angle is close to 0, the optical detection system can determine that the absorption axis of the first linear polarizer (that is, the direction of linear polarization) and the fast axis of the quarter-wave plate (that is, the direction of circular polarization) of the component under test are not offset, which can ensure that each component under test detected by the optical detection system has the same quality performance. In addition, the detection unit of the optical detection system does not need to input material-related parameters (such as thickness, refractive index, and extinction coefficient) of the component to be tested when detecting the component to be tested, which can save time for the optical detection system to perform detection and reduce overall operational complexity.

The foregoing outlines features of several embodiments so that those skilled in the art may better understand aspects of the present disclosure. It should be appreciated by those skilled in the art that they may readily use the present disclosure as a basis for designing or modifying other processes and structures, so as to achieve the same purposes and/or achieve the same advantages as the embodiments described herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

100: Optical detection system 100a: Optical detection system 110: light source 112: light emitting surface 120: Polarization adjustment component 122: Depolarizer 124: second linear polarizer 130: detection unit 132: receiving surface 140: beam reducer 200: component under test 210: The first linear polarizer 220: quarter wave plate 230: Substrate 410:Measuring line segment 420: Experimental line segment 510: Measure line segment 520: Experimental line segment 610: Experimental line segment 620: Experimental line segment 710: ideal line segment 720: Measure line segment 730:Measuring line segment 810:Measuring line segment 820:Measuring line segment a: angle b: angle L: light P1: non-polarized light P2: linearly polarized light P3: circularly polarized light S1: step S2: step S3: step S4: step

One embodiment of the present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIG. 1 is a schematic diagram illustrating the operation of an optical detection system according to an embodiment of the present disclosure. FIG. 2 shows a flow chart of the operation method of the optical detection system according to an embodiment of the present disclosure. FIG. 3 shows the relationship between the fast axis and the absorption axis according to an embodiment of the present disclosure. FIG. 4A to FIG. 7 show the relationship between the phase difference angle and the elliptical polarization ratio according to different embodiments of the present disclosure. FIG. 8A shows the relationship between angle and light intensity according to an embodiment of the present disclosure. FIG. 8B shows the relationship between angle and ellipticity according to an embodiment of the present disclosure. FIG. 9 is a schematic diagram illustrating the operation of an optical detection system according to another embodiment of the present disclosure.

Domestic deposit information (please note in order of depositor, date, and number) none Overseas storage information (please note in order of storage country, institution, date, and number) none

100: Optical detection system

110: light source

112: light emitting surface

120: Polarization adjustment component

122: Depolarizer

124: second linear polarizer

130: detection unit

132: receiving surface

200: component under test

210: The first linear polarizer

220: quarter wave plate

230: Substrate

L: light

P1: non-polarized light

P2: linearly polarized light

P3: circularly polarized light

Claims (9)

An optical detection system configured to detect a DUT having a first linear polarizer and a quarter wave plate, the optical detection system comprising: a light source having a light exit surface configured to emit a light; a polarization adjustment component facing the light exit surface of the light source and configured to convert the light into a linearly polarized light, wherein the first linear polarizer is located between the polarization adjustment component and the quarter wave plate, the DUT is configured to convert the linearly polarized light into a circularly polarized light, wherein the polarization adjustment component includes: A depolarizer, located between the light source and the first linear polarizer of the DUT, configured to convert the light into a non-polarized light; and a detection unit, located on the side of the DUT facing away from the polarization adjustment component, and configured to calculate a phase difference angle between an absorption axis of the first linear polarizer of the DUT and a fast axis of the quarter-wave plate of the DUT according to the circularly polarized light. The optical detection system as claimed in claim 1, wherein the polarization adjustment component further comprises: a second linear polarizer, located between the depolarizer and the first linear polarizer of the device under test, and configured to convert the unpolarized light into the linear polarized light. The optical inspection system as described in claim 1 further includes: a beam reducer located between the DUT and the inspection unit. The optical detection system as claimed in claim 1, wherein the central wavelength of the quarter-wave plate is the same as the wavelength of the light. The optical detection system as claimed in claim 1, wherein the light source is a laser light source. An operation method of an optical detection system, comprising: using a light source to transmit a light to a polarization adjustment component; converting the light into a linearly polarized light by the polarization adjustment component and sending it to a device under test, wherein the device to be tested has a first linear polarizer and a quarter wave plate, the first linear polarizer is located between the polarization adjustment component and the quarter wave plate, wherein the light is converted into the linear polarized light by the polarization adjustment component and emitted to the device under test. The depolarizer converts the light into a non-polarized light and transmits it to a second linear polarizer of the polarization adjustment component; and converts the polarized light into the linear polarized light by the second linear polarizer of the polarization adjustment component and transmits it to the element under test; converts the linearly polarized light into a circularly polarized light through the component under test and transmits it to a detection unit; . The method as described in claim 6, wherein calculating the phase difference angle according to the circularly polarized light further comprises: rotating the DUT to obtain a light intensity and an optical rotation intensity of the DUT; and calculating a maximum elliptical polarization rate of the DUT according to the light intensity and the optical rotation intensity. The method as described in claim 6, wherein calculating the phase difference angle according to the circularly polarized light further comprises: rotating the second linear polarizer to obtain a light intensity and an optical rotation intensity of the DUT; and calculating a maximum elliptic polarization rate of the DUT according to the light intensity and the optical rotation intensity. The method as described in claim 6, wherein converting the linearly polarized light into the circularly polarized light by the device under test and sending it to the detection unit further includes: reducing the spot diameter of the circularly polarized light passing through the device under test to between 0.1 mm and 5 mm by a beam shrinker and sending it to the detection unit.

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