Optical film axis angle measurement device and method

Abstract

This invention provides an optical thin film axis angle measurement device and method, comprising a frame and a light source module, a first polarization component, a detection platform, a second polarization component, a beam splitting module, an imaging module, and a data processing system sequentially arranged along the optical path on the frame. A reference line is provided on the measurement area of ​​the detection platform, which is fixedly located between the first and second polarization components. The first and second polarization components are mounted on the frame via a hollow turntable. The imaging module includes a vision detection system and a power detection system. Light is split into two paths by the beam splitting module and enters the vision detection system and power detection system respectively. The data processing system processes the data. When the sample to be measured is a polarized thin film, only the first polarization component rotates. When the sample to be measured is a birefringent thin film, the first and second polarization components rotate synchronously. This measurement device and method can be applied to the rapid and accurate measurement of the axis angles of various optical thin films.

Description

Technical Field

[0001] This invention pertains to optical detection devices, and more particularly to an optical thin film axis angle measuring device and method. Background Technology

[0002] The axial angle characteristics of optical thin films play a crucial role in polarized light fields. The axial angle has the function of changing the polarization state in a polarized light field. Therefore, in order to stably obtain light with a set polarization state, it is essential to know the axial angle of the optical thin film being used. Existing axial angle measuring devices can generally only measure the axial angle of polarizing films. However, they cannot effectively measure the axial angle of other optical thin films such as reflective films, antireflective films, filter films, optical protective films, beam splitters, and phase films used in polarized fields. Moreover, existing axial angle measuring devices are complex in structure, difficult to operate, and require extremely strict sample placement during testing. Otherwise, errors can easily occur in the results. For example, if the sample is not strictly aligned with the baseline, the test results will have a large deviation. Summary of the Invention

[0003] In view of the above, the present invention provides an optical thin film axis angle measuring device and method, which can be applied to the rapid and accurate measurement of various optical thin film axis angles. The specific technical solution is as follows.

[0004] An optical thin film axis angle measuring device is characterized by comprising a frame and a light source module, a first polarization component, a detection platform, a second polarization component, a beam splitting module, an imaging module, and a data processing system sequentially arranged along the optical path on the frame. A reference line is provided on the measurement area of ​​the detection platform, which is fixedly located between the first and second polarization components. The first and second polarization components are mounted on the frame via a hollow turntable. The imaging module includes a vision detection system and a power detection system. Light is split into two paths by the beam splitting module and enters the vision detection system and the power detection system respectively. The data processing system is used to receive and process data from the vision detection system and the power detection system.

[0005] Furthermore, the center of the measurement area of ​​the detection platform is a light-transmitting window, and the baseline is a horizontal straight line located above the light-transmitting window.

[0006] Furthermore, a depolarizer is provided between the light source module and the first polarization component.

[0007] Furthermore, the light source module includes a light source and a collimating lens in sequence along the optical path.

[0008] Furthermore, the beam splitting module is a semi-transparent, semi-reflective mirror that receives light passing through the second polarization component and splits it into two beams of light in different directions, which are then directed into the visual inspection system and the power detection system.

[0009] Furthermore, a reflecting prism is also provided between the semi-transparent mirror and the visual inspection system to adjust the angle of the light incident on the visual inspection system.

[0010] Furthermore, a focusing lens is also provided between the semi-transparent mirror and the power detection system to further focus the light entering the power detection system.

[0011] An optical thin film axis angle measurement method is provided, which uses the above-mentioned device for measurement and includes the following steps.

[0012] The sample to be tested is placed in the upper light-transmitting window of the measurement area of ​​the detection platform. The visual inspection system collects the tilt angle deviation between the sample edge and the baseline and performs visual correction. The light is collimated and depolarized by a collimating lens and a depolarizer before entering the first polarization component. Depending on the type of sample to be tested, the system selects whether to drive the first or second polarization component to rotate independently or synchronously. While the polarization components are rotating, the power detection system acquires the change in photocurrent generated by the polarized light passing through the sample to be tested. The data processing system calculates the angle between the optical axis of the sample to be tested and the horizontal baseline by using the change in photocurrent and the axis angle of the polarization component, and then obtains the axis angle of the sample to be tested.

[0013] Furthermore, when the sample to be tested is a polarized thin film, the motor drives the hollow turntable to rotate the first polarization component, while the second polarization component remains stationary. When the sample to be tested is a birefringent thin film, the motor drives the hollow turntable to rotate the first and second polarization components synchronously.

[0014] The optical thin film axis angle measuring device of the present invention comprises, sequentially along the optical path, a light source, a collimating lens, a depolarizer, a first polarization component, a detection platform, a second polarization component, a beam splitting module, a vision inspection system, and a power detection system. The optical thin film sample to be tested is placed on the detection platform. If the sample is a polarization-type thin film such as a polarizer, only the first polarization component is driven to rotate. Then, the axis angle of the sample can be quickly determined based on the light-current change relationship obtained by the power detection system. If the sample is a biaxial birefringent thin film such as a compensation film, release film, or protective film, the first and second polarization components are driven to rotate synchronously. Then, the axis angle of the sample can be determined based on the light-current change relationship obtained by the power detection system. Therefore, this device can conveniently and quickly obtain the axis angles of various optical thin films, making it highly applicable. Furthermore, it requires minimal operator skill; the sample only needs to be placed on the light-transmitting window of the detection platform. It is not necessary to strictly align the edge of the sample with the baseline, as the vision inspection system can directly correct any deviations during placement, thereby accurately obtaining the axis angle of the sample.

[0015] Additional aspects and advantages of the invention will be further set forth in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the optical thin film axis angle measuring device of the present invention; Figure 2 This is a schematic diagram of the optical path structure of the present invention; Figure 3 This is a schematic diagram of the measurement area of ​​the detection platform of the present invention; Figure 4 This is a fitted curve of illuminance versus deflection angle when only the first polarization component rotates; Figure 5 The fitting curve of illuminance versus deflection angle when the first polarization component and the second polarization component rotate synchronously; Among them, 1-visual inspection system, 2-reflecting prism, 3-focusing lens, 4-power detection system, 5-spectrum splitting module, 6-second polarization component, 7-detection platform, 71-measurement area, 72-transmitting window, 73-baseline, 8-first polarization component, 9-depolarizer, 10-light source module, 101-light source, 102-collimating lens, 11-sample to be tested, 12-hollow turntable, 13-frame. Detailed Implementation

[0017] In the description of this invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0018] Reference Figures 1-3This embodiment of an optical thin film axis angle measuring device includes a frame 13 and a light source module 10, a first polarization component 8, a detection platform 7, a second polarization component 6, a beam splitting module 5, an imaging module, and a data processing system, which are sequentially arranged along the optical path on the frame 13. A reference line 73 is provided on the measurement area of ​​the detection platform 7. The measurement platform 7 is fixedly located between the first polarization component 8 and the second polarization component 6. The first polarization component 8 and the second polarization component 6 are mounted on the frame 13 via a hollow turntable 12, which is driven to rotate by an external motor. The imaging module includes a vision detection system 1 and a power detection system 4. Light is split into two paths by the beam splitting module 5 and enters the vision detection system 1 and the power detection system 4 respectively. In this embodiment, the data processing system can be a computer with image and data analysis functions, connected to the vision detection system 1 and the power detection system 4, for processing the data received by both. Further details are omitted here, but those skilled in the art will understand.

[0019] Furthermore, the center of the measurement area 71 of the detection platform 7 is the light-transmitting window 72, and the baseline 73 is a horizontal straight line located above the light-transmitting window 72.

[0020] In this embodiment, a depolarizer 9 is also provided between the light source module 10 and the first polarization component 8. The light source module 10 includes a light source 101 and a collimating lens 102 in sequence along the optical path, that is, the depolarizer 9 is located between the collimating lens 102 and the first polarization component 8.

[0021] The preferred beam splitter module 5 is a semi-transparent, semi-reflective mirror that receives light passing through the second polarization component 6 and splits it into two beams of light with different directions, which are then directed into the vision detection system 1 and the power detection system 4, respectively. Additionally, a reflecting prism 2 is disposed between the semi-transparent, semi-reflective mirror and the vision detection system to adjust the angle of the light incident on the vision detection system 1. A focusing lens 3 is also disposed between the semi-transparent, semi-reflective mirror and the power detection system 4 to further focus the light entering the power detection system 4.

[0022] The preferred light source 101 is an LED light source, the visual inspection system 1 is a camera, and the power detection system 4 is a light meter and a light power detector.

[0023] In this embodiment, the LED light source can improve light utilization through the collimating lens 102, and then obtain unpolarized light through the depolarizer 9, avoiding measurement errors caused by the polarization characteristics of the light source itself. Then, it passes through the first polarization component 8 to form a polarized light field. The first polarization component 8 plays a polarizing role. The sample to be tested 11 is placed on the detection platform 7 along the reference line 73. The tilt angle deviation between the sample to be tested and the reference line 73 can be corrected by the vision inspection system 1. Then, the polarized light after passing through the sample to be tested 11 passes through the second polarization component 6. A photometer and a light power detector are installed at the rear end of the second polarization component 6. By obtaining the relationship between the brightness and current change generated by the polarized light passing through the sample, the axis angle of the optical thin film to be tested can be accurately obtained.

[0024] The optical thin film axis angle measurement method of this embodiment includes the following steps: S1. The sample 11 to be tested, which is cut into a rectangle, is placed in the light-transmitting window 72 on the measurement area 71 of the detection platform 7. The visual inspection system 1 collects the tilt angle deviation between the sample edge and the baseline 73, performs visual correction, and obtains a compensation angle θ3 for the deviation between the actual sample and the baseline.

[0025] S2. The light is collimated and depolarized by the collimating lens 102 and the depolarizer 9 before entering the first polarization component 8.

[0026] S3. Select whether to drive the first polarization component 8 or the second polarization component 6 to rotate independently or synchronously, depending on the type of the sample 11 to be tested.

[0027] A: When the sample to be tested is a polarized thin film, the motor drives the hollow turntable 12 to rotate the first polarization component 8, while the second polarization component 6 remains stationary.

[0028] B: When the sample to be tested is a birefringent thin film, the motor drives the hollow turntable 12 to drive the first polarization component 8 and the second polarization component 6 to rotate synchronously.

[0029] S4. When the polarization component rotates, the power detection system 4 obtains the relationship between the change in photocurrent generated by polarized light passing through the sample under test.

[0030] S5. The data processing system calculates the angle between the optical axis of the sample under test and the horizontal baseline by the change in illumination current and the axis angle of the polarization component, and then obtains the axis angle of the sample under test.

[0031] The Mueller matrix of linearly polarized light with an axial direction of θ1, i.e., the Mueller matrix of the first polarization component, is as follows. The axial direction is θ s The Mueller matrix of the sample thin film with a phase delay of φ

[0032] A: When the sample to be tested is a polarized thin film, only the first polarization component 8 rotates.

[0033] The energy value detected by power detection system 4 is I = M P2 M PS M P1 S0, Where M p2 This represents the second polarization component. In this case, the second polarization component maintains a fixed angle, so it is a known constant. M ps This indicates that the sample to be tested remains stationary on the detection platform; although its angle is unknown, it will not cause any change in the detector's energy. M p1 This represents the first polarization component, which rotates by a set angle θ1, and the final energy value I changes with angle θ1. S0 is the Stockhorse vector of the unpolarized light.

[0034] so The energy I detected by the power detection system varies with θ1. By setting different angles θ1, different energies I are obtained, with reference to... Figure 4 By fitting the curve of illuminance versus deflection angle, and taking the current value corresponding to the extreme point, θ can be calculated by substituting it into the above formula. s θ s This refers to the axial angle of the sample to be measured. If the sample is misplaced, the true axial angle of the sample to be measured is θ. s +θ3.

[0035] B: When the sample to be tested is a birefringent thin film, the first polarization component 8 and the second polarization component 6 rotate synchronously.

[0036] In this situation, the energy value detected by power detection system 4 is... I = M P2 M Q M P1 S c , Where M p1 This refers to the first polarization component, which rotates by a set angle θ1. M p2 Let S0 represent the second polarization component. In this case, the second polarization component rotates synchronously with the first polarization component 8, meaning the changing rotation angles are the same. Initially, the axial angles of the first polarization component 8 and the second polarization component 6 differ by 90°. Therefore, when they rotate synchronously, the axial angle of the second polarization component 6 is θ2 = θ1 + 90°. S0 is the Stockholm vector of the unpolarized light. so The detector energy I varies with θ1. During the measurement, the sample remains stationary, and φ and θ... s Nothing will change; the change in θ1 will bring about a change in I, as referenced. Figure 5 By fitting the curve of illuminance versus deflection angle, and taking the current value corresponding to the extreme point, θ can be calculated by substituting it into the above formula. s θ s This refers to the axial angle of the sample to be measured. If the sample is misplaced, the true axial angle of the sample to be measured is θ. s +θ3.

[0037] Although specific embodiments of the invention have been described in detail with reference to illustrative examples, it should be understood that those skilled in the art can devise various other modifications and embodiments that fall within the spirit and scope of the invention. Specifically, reasonable variations and modifications can be made to the arrangement of components and / or dependent combinations within the scope of the foregoing disclosure, drawings, and claims without departing from the spirit of the invention. The scope of these variations and modifications, except for those concerning components and / or layout, is defined by the appended claims and their equivalents.

Claims

1. An optical film axial angle measurement method characterized by, The optical thin film axis angle measurement device is used for measurement. The device includes a frame (13) and a light source (101), a collimating lens (102), a depolarizer (9), a first polarization component (8), a detection platform (7), a second polarization component (6), a beam splitting module (5), an imaging module, and a data processing system arranged sequentially along the optical path on the frame (13). A reference line (73) is provided on the measurement area of ​​the detection platform (7). The detection platform (7) is located between the first polarization component (8) and the second polarization component (6). The first polarization component (8) and the second polarization component (6) are arranged on the frame (13) through a hollow turntable (12). The imaging module includes a vision detection system (1) and a power detection system (4). The light is split into two paths by the beam splitting module (5) and enters the vision detection system (1) and the power detection system (4) respectively. The data processing system is used to receive and process the data of the vision detection system (1) and the power detection system (4). The steps include The sample to be tested (11) is placed in the light-transmitting window (72) on the measurement area (71) of the detection platform (7). The visual detection system (1) collects the tilt angle deviation between the sample edge and the baseline (73) and performs visual correction. The light is collimated and depolarized by a collimating lens (102) and a depolarizer (9) before entering the first polarizing component (8); When the sample to be tested is a polarized thin film, the motor drives the hollow turntable (12) to drive the first polarization component (8) to deflect, while the second polarization component (6) remains stationary; When the sample to be tested is a birefringent thin film, the motor drives the hollow turntable (12) to drive the first polarization component (8) and the second polarization component (6) to rotate synchronously; When the polarization component rotates, the power detection system (4) obtains the change relationship of the photocurrent generated by the polarized light passing through the sample under test; The data processing system calculates the angle between the optical axis of the sample under test and the horizontal baseline by measuring the changes in illumination current and the rotation angle of the polarization component, and then obtains the axial angle of the sample under test.

2. The optical film axial angle measurement method according to claim 1, wherein The center of the measurement area (71) of the detection platform (7) is a light-transmitting window (72), and the baseline (73) is a horizontal straight line located above the light-transmitting window (72).

3. The optical film axial angle measurement method according to claim 1, wherein The beam splitting module (5) is a semi-transparent and semi-reflective mirror that receives light passing through the second polarization component (6) and splits it into two beams of light in different directions, which are then injected into the visual detection system (1) and the power detection system (4).

4. The optical film axial angle measurement method according to claim 3, wherein A reflecting prism (2) is also provided between the semi-transparent mirror and the visual inspection system to adjust the angle of the light incident on the visual inspection system (1).

5. The optical film axial angle measurement method according to claim 3, wherein A focusing lens (3) is also provided between the semi-transparent mirror and the power detection system (4).

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