TW201828395A - Polarizer calibration device and method capable of precisely calibrating the angle between an alignment mark line and a polarizing axis - Google Patents

Abstract

The present invention provides a polarizer calibration device and method. The polarizer calibration device comprises a light source unit for generating non-polarized collimated light source; a polarizer fastening unit for fastening the polarizer; a detector for detecting an alignment mark of the polarizer; a polarization detection unit disposed below the polarizer fastening unit with a position corresponding to the polarizer; and a working table for carrying the fastening unit of the polarizer and the polarization detection unit for performing a horizontal movement. The polarizer calibration device and method according to the present invention may precisely calibrate the angle between an alignment mark line and a polarizing axis, so as to solve the problem that the angle between the alignment mark line and the polarizing axis may be deviated after experiencing different manufacturing processes.

Description

Polarizer calibration device and method

The present invention relates to the field of polarizer calibration, and in particular to a polarizer calibration device and method.

As we all know, polarizers, glass slides, liquid crystals, etc. all have polarization characteristics, and a large number of these components with polarization characteristics are used in optical products and experiments. Detection of the polarization angle or optical axis angle of these elements is particularly important.

As shown in Figure 1, in some product manufacturing processes, it is necessary to use a polarizing plate with both an alignment mark 12 and a polarizing area 11; Different processes, such as the use of immersion interference photolithography for the polarized area 11 and mask projection lithography or electron beam lithography for the alignment mark 12 have undergone two completely different process processes. Later, it is difficult to ensure or measure whether the angle Φ between the alignment mark line 14 and the polarization axis 13 of the polarizer is changed, which affects the accuracy of the product using the polarizer.

In order to overcome the conventional problems, the present invention provides a polarizing plate calibration device and method, so as to solve the problem that the angle between the alignment mark connecting line and the polarization axis is easy to deviate after the polarizing plate undergoes different processes.

To achieve the above object, the present invention provides a polarizer calibration device, including: a light source unit for generating a non-polarized collimated light source; a polarizer fixing unit for fixing a polarizer; and a detector for detecting a pair of polarizers. Quasi-markers; an analyzer unit, which is arranged below the polarizer fixing unit, corresponding to the position of the polarizer; and a table for carrying the polarizer fixing unit and the analyzer unit for horizontal movement.

Preferably, the analysis unit includes an analysis wire grid, a rotating electric machine, and a light energy detector, wherein the light energy detector and the rotating electric machine are both installed on a workbench, and the analysis wire grid is disposed on the rotating electric machine and can be connected to the rotating electric machine. Driven by the vertical rotation.

Preferably, the positions of the light source unit, the polarizing plate, and the analyzer unit are set so that the non-polarized collimated light emitted by the light source unit can be sequentially received by the light energy detector after passing through the polarizer and the analyzer wire grid.

Preferably, the detector is an aligned CCD camera.

Preferably, the polarizing plate fixing unit includes a holding frame support and a holding frame, the polarizing plate is fixedly installed on the holding frame, the holding frame is installed on the workbench through the holding frame support, and the holding frame can be opposite to The holder support is rotated so that the polarizer can be in at least a first position facing up and a second position facing down.

Preferably, the holding frame is provided with a groove, the polarizing plate is fixed in the groove, and the holding frame is made of a light-transmitting material.

Preferably, the mounting surface of the holder support and the holder defines a reference direction. The polarizer calibration device further includes or is connected to a controller, and the controller is used to control the table to move the alignment mark of the polarizer to Within the detection field of view of the detector, the angle θ between the reference direction and the alignment mark of the polarizer is calculated based on the position information of the alignment mark obtained by the detector.

Preferably, the controller is further configured to: control the table to move the polarizer fixing unit and the analyzer unit to positions corresponding to the light source unit; and under the first and second positions of the polarizer, respectively control the rotating motor to drive the detector The polarization grid rotates and controls the light energy detector to detect the light passing through the polarizer and the analyzer in turn; and the angle α between the reference direction and the polarization axis of the polarization plate is calculated according to the detection result of the light energy detector.

Preferably, the controller is further configured to calculate an interval between the alignment mark line of the polarizer and the polarization axis based on an included angle θ between the reference direction and the alignment mark of the polarizer and the included angle α of the reference direction and the polarization axis of the polarizer. Angle Φ.

Preferably, the worktable includes a slide table and a linear guide, the slide table is mounted on the linear guide, and the polarizing plate fixing unit and the analyzer are arranged on the slide table.

In order to achieve the above object, the present invention further provides a method for calibrating the direction of a polarizer, which uses the above-mentioned device for calibrating a direction of a polarizer and includes the following steps:

Step 1: Set a reference direction;

Step 2: Measure the angle θ between the alignment mark line of the polarizer and the reference direction;

Step 3: measure the angle α between the polarization axis of the polarizer and the reference direction;

Step 4. According to the results of steps 2 and 3, calculate the angle Φ between the alignment mark line of the polarizer and the polarization axis.

Preferably, step 2 includes:

Step 21: the detector detects a signal of one of the alignment marks on the polarizer and calculates the position of the alignment mark;

Step 22: the detector detects the signal of another alignment mark on the polarizer and calculates the position of the other alignment mark;

Step 23: Calculate the angle between the alignment mark line and the reference direction based on the position of one of the alignment marks and the other alignment mark on the polarizer.

Preferably, step 23 includes calculating the X-direction distance and the Y-direction distance between the two alignment marks according to the positions of one of the alignment marks and the other alignment mark on the polarizer, and according to the X-direction distance and the Y-direction distance Calculate the angle between the alignment mark line and the reference direction, where the Y direction is the reference direction and the X direction is the direction perpendicular to the Y direction in the horizontal plane.

Preferably, step 3 includes:

Step 31: project the unpolarized collimated light emitted from the light source unit to the surface of the polarizer;

Step 32: The rotation motor in the analysis unit drives the rotation of the detection wire grid, and the light energy detector detects and selects the first rotation angle α1 of the rotation motor when the light intensity is minimum after passing through the detection wire grid;

Step 33: flip the polarizer, the rotating motor in the analyzer unit drives the analyzer wire grid to rotate again, and the light energy detector detects and selects the second rotation angle α2 of the rotary motor when the light intensity is minimum after passing through the analyzer wire grid;

Step 34: According to the results of steps 32 and 33, an angle α between the polarization axis of the polarizer and the reference direction is calculated.

Preferably, in step 33, flipping means that the polarizing plate is changed from the front side to the front side.

Preferably, in steps 32 and 33, the light intensity change after passing through the calibration wire grid is fitted by a function, and the rotation angle of the rotating motor is selected when the light intensity after passing through the calibration wire grid is the smallest.

Preferably, the function is a Fourier function.

Preferably, in step 4, the angle θ between the alignment mark line and the polarization axis is obtained by summing the angle θ between the alignment mark line and the reference direction to obtain the angle Φ between the alignment mark line and the reference axis. .

Preferably, step 2 is performed before or after step 3.

The polarizer calibration device and method provided by the present invention include a polarizer fixing unit, a detector, an analyzer, and a workbench control unit based on the original equipment. The polarizer calibration method is used to accurately calibrate the polarizer before using the polarizer. The angle between the polarizer alignment mark line and the polarization axis solves the problem that the angle between the polarizer alignment line and the polarization axis of the polarizer deviates after undergoing different processes.

In order to make the foregoing objects, features, and advantages of the present invention more comprehensible, the embodiments of the present invention are described in detail below with reference to the drawings. It should be noted that the drawings of the present invention are in simplified form and use inaccurate proportions, and are only used to facilitate and clearly explain the purpose of the embodiments of the present invention.

As shown in Figure 2, the polarizer calibration device of the present invention includes:

Light source unit 1 for generating a non-polarized collimated light source;

A polarizer fixing unit for fixing the polarizer 4;

A detector for detecting an alignment mark on the polarizer 4; the detector of this embodiment preferably uses an alignment CCD camera 2;

An analysis unit is disposed below the polarizer fixing unit, and the position corresponds to the polarizer 4;

And a worktable for realizing horizontal movement of the polarizing plate 4 and the analysis unit; the polarizing plate fixing unit and the analysis unit are arranged on the worktable.

As shown in FIG. 1, the polarizer is provided with two alignment marks 12 and a polarization axis 13. To show the difference, the two alignment marks 12 are hereinafter referred to as a first alignment mark 16 and a second pair, respectively. Quasi-marker 17.

Continuing to refer to FIG. 2, the table includes a linear guide 9 and a slide table 10. The slide table 10 is mounted on the linear guide 9. Specifically, the slide table 10 can slide horizontally on the linear guide 9 to drive polarization. The plate 4 and the analysis unit are moved in a horizontal direction, so that the alignment mark 12 on the polarizing plate 4 can enter the field of view of the alignment CCD camera 2, and the alignment CCD camera 2 obtains an alignment mark signal.

Further, the polarizing plate fixing unit includes a clamping frame mounting base 3, two clamping frame supporting columns, and a clamping frame 5, the clamping frame 5 is provided with a groove, and the polarizing plate 4 is fixedly mounted on the In the groove; the clamping frame 5 is mounted on the clamping frame mounting base 3, the clamping frame mounting base 3 is mounted on two clamping frame supporting columns, and the clamping frame supporting columns Set on the slide table 10.

Furthermore, as shown in Figs. 3 and 4, the holder mounting base 3 has a leaning surface with a high flatness, and the holder 5 has at least one side (the holder plane 18) There is also a high degree of flatness, and the side surface (clamping frame plane 18) and the abutment surface closely fit together to form a mounting surface between the clamping frame mounting seat 3 and the clamping frame 5. The polarizer orientation calibration device of the present invention defines a reference direction 15. The preferred horizontal direction in this embodiment is the reference direction 15, for example, it is defined as the horizontal Y-axis direction. The extension direction of the mounting surface is consistent with the reference direction 15. The polarizing axis 13 of the polarizing plate 4 on the holder 5 forms a first angle (having an angle value α) with the reference direction 15, as shown in FIG. 12, and the two alignment marks 14 and the reference direction 15 of the polarizing plate 4 A second included angle is formed (having an angle value θ).

The direction perpendicular to the reference direction 15 in the horizontal plane is the X-axis direction. As shown in FIGS. 10 to 13, the holder 5 is designed to drive the polarizing plate 4 to rotate about the Y-axis direction. Specifically, after the holder 5 is rotated 180 ° around the Y-axis direction from the position shown in FIG. 12, the polarizing plate 4 is also driven to rotate 180 ° around the Y-axis direction. At this time, as shown in FIG. 13, the polarization The angle between the axis 13 and the reference direction 15 is −α, that is, the polarization axis 13 is rotated by an angle of 2α relative to the reference direction 15.

Those skilled in the art can easily understand that the above-mentioned clamping frame mounting seat 3 and the clamping frame supporting column can also be integrally formed into a single component, and the installation method of the polarizing plate 4 is not limited to the above embodiment, and any polarizing plate 4 The mounting structure that is maintained above the analysis unit and can realize the flip of the polarizer 4 (from front to top to front to bottom) can be used to replace the above-mentioned polarizer fixing unit.

Continuing to refer to FIG. 2, the analysis unit includes an analysis wire grid 6, a rotary electric machine 7, and a light energy detector (ED) 8. The light energy detector 8 is mounted on a slide table 10. The rotary electric machine 7 is, for example, It is a ring-shaped motor, which is arranged on the outer periphery of the light energy detector 8 and is mounted on the slide table 10. The calibration wire grid 6 is mounted on the rotary electric machine 7, that is, only the peripheral portion of the calibration wire grid 6 is supported on the rotary electric machine 7. In the upper part, the central part is not supported, and the position of the detection wire grid 6 and the light energy detector 8 correspond to each other. Specifically, the rotating electric machine 7 can rotate about the vertical Z axis and drive the analyzer wire grid 6 to rotate about the Z axis together, thereby changing the angle between the grating direction of the analyzer wire grid 6 and the polarization axis 13 of the polarizer 4. At the same time, the light energy detector 8 obtains the light intensity information of the light emitted from the light source unit 1 during the rotation of the analyzer wire grid 6 after passing through the polarizer 4 and the analyzer wire grid 6 in sequence. The grating direction is related to the included angle between the polarization axes 13 of the polarizer 4.

Those skilled in the art can easily understand that, in order to allow the light emitted from the light source unit 1 to be irradiated onto the analyzer wire grid 6 through the polarizing plate 4, the clamping frame 5 is preferably made of a light-transmitting material or a ring shape. The structure is such that the light transmitted through the central portion of the polarizing plate 4 can be incident on the analyzer wire grid 6 substantially unaffected. In addition, the light emitted by the light source unit 1 is preferably incident on the surface of the polarizing plate 4 vertically (along the Z-axis direction).

It is easier for those with ordinary knowledge in the art to understand that one or more of the light source unit 1, the polarizer fixing unit, the detector, the analyzer, and the workbench can be controlled by a controller, and the controller can be integrated in the corresponding component. In the middle or through external connection, you can set up or share a total controller. The processing of the data obtained by the detector and / or the processing of the data obtained by the analysis unit may also be implemented by the controller, or processed by other processing equipment. Since these are well-known and easy to implement methods in the art, they are not listed one by one.

This embodiment further provides a method for calibrating the direction of a polarizer. As shown in FIG. 5, the method specifically includes:

In the first step, a reference direction 15 is set. In this embodiment, the horizontal Y direction is preferably the reference direction 15.

In the second step, the angle between the alignment mark line 14 and the reference direction 15 on the polarizer is measured and calculated, as shown in Fig. 6, as follows:

As shown in FIGS. 3 and 7, the slide table 10 is moved in the X direction so that the first alignment mark 16 enters the alignment field of view of the CCD camera 2, and the CCD camera 2 is aligned to obtain the signal of the first alignment mark 16. The position of the first alignment mark 16 on the photosensitive surface of the alignment CCD camera 2 is calculated by a digital image processing algorithm;

Continue to move the slide table 10 in the X direction so that the second alignment mark 17 enters the alignment field of view of the CCD2, and align the CCD camera 2 to obtain the signal of the second alignment mark 17 and calculate the second pair through the digital image processing algorithm The position of the quasi mark 17 on the photosensitive surface of the alignment CCD camera 2; in this embodiment, the size of the alignment field of view of the alignment CCD camera 2 (the measurable range in the Y direction) is larger than that of the first alignment mark 16 and The Y-direction distance between the second alignment marks 17.

Continuing to refer to FIG. 7, calculate the X-direction distance of the first alignment mark 16 and the second alignment mark 17 as L1, and the Y-direction distance of the first alignment mark 16 and the second alignment mark 17 as L2. The angle between the quasi-marking line 14 and the reference direction 15.

In the third step, the angle between the polarization axis 13 and the reference direction 15 is measured, as shown in Fig. 8, as follows:

Turn on the light source unit 1 to generate a non-polarized collimated light source perpendicularly incident on the surface of the polarizer 4;

Start the rotary motor 7 to drive the analyzer wire grid 6 to rotate. In synchronization, the light energy detector 8 collects the light intensity after passing through the analyzer wire grid 6, as shown in Figure 9. According to Marius's law, the light intensity changes with the analyzer. The rotation angle of the wire grid 6 exhibits a sinusoidal change. The function is used to fit the sine curve. In this embodiment, a Fourier function is preferably used to calculate the rotation angle of the rotary motor 7 when the light intensity is minimum.

Rotating motor 7 return to zero;

As shown in Figures 10 to 13, if the holder 5 is rotated 180 ° about the Y axis, the polarizer 4 is driven to rotate 180 ° about the Y axis, and the angle between the polarization axis 13 and the reference direction 15 becomes -α, which is polarization Axis 13 changed by 2α;

Once again, the rotary motor 7 is started to drive the detection wire grid 6 to rotate. In a synchronous manner, the light energy detector 8 collects the light intensity after passing through the detection wire grid 6. According to Marius's law, the light intensity rotates with the detection wire grid 6 The angle exhibits a sinusoidal change. As shown in FIG. 9, a suitable function is used to fit the sine curve. Here, it is preferable to use a Fourier function to calculate the rotation angle of the rotary motor 7 when the light intensity is minimum at α2;

To obtain the amount of change in the direction of the polarization axis 13 as α2-α1;

Finally, the angle between the polarization axis 13 and the reference direction 15 is calculated as α = (α2-α1) / 2. The difference between the two rotation angles of the rotating electric machine 7 is used to calculate the included angle α, which can eliminate the calibration of the zero position (0 degree position) of the rotating electric machine 7, and can more accurately offset the measurement error, thereby improving the measurement accuracy.

In the fourth step, the angle between the alignment mark line 14 and the polarization axis 13 is calculated based on the results of the second and third steps, as follows:

Sum the angle θ between the alignment mark line 14 and the reference direction 15 and the angle α between the polarization axis 13 and the reference direction 15, that is, the angle Φ between the alignment mark line 14 and the polarization axis 13 = θ + α, where the single calibration accuracy of Φ is 0.01.

Through the above method, the angle between the alignment mark line 14 of the polarizing plate 4 and the polarization axis 13 can be conveniently and accurately measured.

Those skilled in the art should understand that the description order of the above embodiments should not limit the execution order of the steps of the above method. For example, in the second step, the second alignment mark 17 may be first entered into the alignment of the CCD camera 2. In the quasi-field of view, the first alignment mark 16 is brought into the alignment field of view of the CCD camera 2 again, and the calculation formula of the included angle θ is unchanged. As another example, the second step may be performed after the third step, that is, firstly, the angle α is obtained, and then the angle θ is obtained. As long as Φ can be finally obtained, the order of each step in the above method and the sub-steps in each step can be flexibly adjusted.

Obviously, those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. In this way, if these modifications and variations of the present invention fall within the scope of the patent application for the present invention and the scope of equivalent technologies, the present invention also intends to include these modifications and variations.

1‧‧‧light source unit

10‧‧‧Slide

11‧‧‧from the partial area

12‧‧‧ alignment mark

13‧‧‧ polarization axis

14‧‧‧ alignment mark connection

15‧‧‧ reference direction

16‧‧‧ First alignment mark

17‧‧‧Second alignment mark

18‧‧‧ flat plane

2‧‧‧ aimed at CCD camera

3‧‧‧ Clamping Frame Mount

4‧‧‧ Polarizer

5‧‧‧ clamping frame

6‧‧‧Analysis wire grid

7‧‧‧ rotating motor

8‧‧‧ Light Energy Detector

9‧‧‧ linear guide

Figure 1 is a schematic diagram of the angle between the polarization axis and the alignment mark on the polarizer. Figure 2 is a schematic diagram of a polarizer calibration device according to the present invention. Fig. 3 is a schematic cross-sectional view of a clamping frame according to the present invention. FIG. 4 is a schematic cross-sectional view of the positional relationship between the clamping frame mounting seat and the clamping frame according to the present invention. FIG. 5 is a schematic diagram of a method for calibrating an included angle between a polarization axis and an alignment mark of the present invention. FIG. 6 is a flowchart of calibrating the angle between the alignment mark line and the reference direction according to the present invention. FIG. 7 is a schematic diagram of the included angle between the alignment mark line and the reference direction of the present invention. Fig. 8 is a flowchart of the calibration of the angle between the polarization axis and the reference direction of the present invention. FIG. 9 is a schematic diagram of changes in the rotation angle and light intensity of the rotating electric machine according to the present invention. FIG. 10 is a schematic diagram of the polarizer of the present invention at 0 ° with respect to the Y axis. FIG. 11 is a schematic diagram of the polarizer of the present invention after being rotated 180 ° with respect to the Y axis. FIG. 12 is a schematic diagram of the included angle between the polarization axis and the reference direction when the polarizer of the present invention is 0 ° with respect to the Y axis. FIG. 13 is a schematic diagram of the included angle between the polarization axis and the reference direction after the polarizer of the present invention is rotated 180 ° with respect to the Y axis.

Claims (19)

A polarizer calibration device includes: a light source unit for generating a non-polarized collimated light source; a polarizer fixing unit for fixing a polarizer; a detector for detecting an alignment mark of the polarizer; an analyzer unit, The polarizer is arranged below the polarizer fixing unit at a position corresponding to the polarizer; and a table is used for carrying the polarizer fixing unit and the analyzer unit for horizontal movement. The polarizing plate calibration device according to item 1 of the scope of patent application, wherein the analyzer includes an analyzer wire grid, a rotating electric machine, and a light energy detector, and the light energy detector and the rotating electric machine are both installed on the workbench. On the other hand, the detection wire grid is arranged on the rotary electric machine and can be rotated in a vertical direction by the rotary electric machine. The polarizing plate calibration device as described in item 2 of the scope of patent application, wherein the positions of the light source unit, the polarizing plate, and the analyzer unit are set so that non-polarized collimated light emitted by the light source unit can pass through the polarizing plate in order. And the detection wire grid is received by the light energy detector. The polarizing plate calibration device according to any one of claims 1 to 3, wherein the detector uses an aligned CCD camera. The polarizer calibration device according to any one of claims 1 to 3, wherein the polarizer fixing unit includes a holder support and a holder, and the polarizer is fixedly mounted on the holder , The clamping frame is mounted on the table through the clamping frame support, and the clamping frame can be rotated relative to the clamping frame support, so that the polarizer can be at least in a first position and a front side facing up Point down to the second position. The polarizing plate calibration device according to item 5 of the scope of the patent application, wherein the holder is provided with a groove, the polarizer is fixed in the groove, and the holder is made of a light-transmitting material. According to the polarizing plate calibration device described in item 5 of the scope of patent application, wherein the holding frame support member and the mounting surface of the holding frame define a reference direction, the polarizing plate calibration device further includes or is connected to a controller, The controller is configured to: control the table to move the alignment mark of the polarizer into the detection field of view of the detector, and calculate the reference direction and the polarizer according to the position information of the alignment mark obtained by the detector. The angle θ of the alignment line of the alignment mark. The polarizing plate calibration device according to item 7 of the scope of patent application, wherein the controller is further configured to: control the table to move the polarizing plate fixing unit and the analyzer unit to positions corresponding to the light source unit; At the first position and the second position of the polarizing plate, respectively controlling the rotating electrical machine to drive the detection wire grid to rotate and control the light energy detector to detect the light passing through the polarizing plate and the detection wire grid in sequence; and according to the light energy detection The detection result of the polarizer calculates the angle α between the reference direction and the polarization axis of the polarizer. The polarizing plate calibration device according to item 8 of the scope of patent application, wherein the controller is further configured to: according to an angle θ between a line connecting the reference direction and the alignment mark of the polarizing plate; The angle α between the alignment mark line of the polarizer and the polarization axis is calculated. The polarizing plate calibration device according to item 1 of the scope of patent application, wherein the table includes a slide table and a linear guide, the slide table is mounted on the linear guide, and the polarizer fixing unit and the analyzer are disposed on the slide table. . A polarizing plate calibration method using the polarizing plate calibration device described in any one of claims 1 to 10 of the patent application scope. The polarizing plate calibration method includes the following steps: Step 1: Set a reference direction; Step 2: Measure The angle θ between the alignment mark line of the polarizer and the reference direction; step 3: measuring the angle α between the polarization axis of the polarizer and the reference direction; and step 4, according to the results of step 2 and step 3, Calculate the angle Φ between the alignment mark line of the polarizer and the polarization axis. The method for calibrating a polarizer as described in item 11 of the patent application scope, wherein step 2 includes: Step 21: The detector detects a signal of one of the alignment marks on the polarizer and calculates the position of the alignment mark; Step 22: The detector Detecting the signal of another alignment mark on the polarizer and calculating the position of another alignment mark; and step 23: calculating the alignment mark line and the reference based on the positions of one alignment mark and the other alignment mark on the polarizer The angle between the directions. The method for calibrating a polarizer as described in item 12 of the patent application scope, wherein step 23 includes: calculating the X-direction distance between the two alignment marks according to the position of one of the alignment marks and the other alignment mark on the polarizer. And the distance in the Y direction, the angle between the alignment mark line and the reference direction is calculated according to the distance in the X direction and the distance in the Y direction, where the Y direction is the reference direction and the X direction is a direction perpendicular to the Y direction in the horizontal plane. The method for calibrating a polarizer according to item 11 of the scope of patent application, wherein step 3 includes: step 31: projecting non-polarized collimated light from the light source unit onto the surface of the polarizer; step 32: driven by a rotating motor in the analyzer unit The detection grid rotates, and the light energy detector detects and selects the first rotation angle α1 of the rotating motor when the light intensity is minimum after passing through the detection grid. Step 33: Turn the polarizer, and the rotating motor in the detection unit drives the detection again. The wire grid rotates, and the light energy detector detects and selects the second rotation angle α2 of the rotary electric machine when the light intensity after the detection grid is minimized. Step 34: According to the results of step 32 and step 33, a polarizer is calculated. The angle α between the polarization axis and the reference direction. The method for calibrating a polarizing plate as described in item 14 of the scope of the patent application, wherein in step 33, flipping means that the polarizing plate is changed from the front side to the front side. The calibration method of the polarizer as described in item 14 of the scope of the patent application, wherein in step 32 and step 33, the light intensity change after passing through the calibration wire grid is fitted by a function, and the light intensity after passing through the calibration wire grid is selected. Rotation angle of the rotary motor. The calibration method of a polarizer according to item 16 of the scope of the patent application, wherein the function uses a Fourier function. The method for calibrating a polarizer as described in item 11 of the scope of patent application, wherein in step 4, the angle θ between the alignment mark line and the reference direction and the angle α between the polarization axis and the reference direction are summed up. To obtain the angle Φ between the alignment mark line and the polarization axis. The method for calibrating a polarizer as described in item 11 of the scope of patent application, wherein step 2 is performed before or after step 3.