A method for rapid measurement of polarizer absorption axis

Abstract

The present invention provides a method for quickly measuring the absorption axis of a polarizer. By arranging a plurality of single-point analyzer combinations with different known absorption axis angles in the emission direction of the polarizer to be measured, a specific electrical signal is obtained through each single-point analyzer, and a plurality of specific light intensity values ​​can be obtained at one time. The relationship between the angle between the absorption axis of the analyzer and the absorption axis of the polarizer to be measured can be calculated by substituting the obtained multiple light intensity values ​​into a formula. Since the absorption axis of the analyzer is known, the absorption axis of the polarizer to be measured can also be quickly obtained. Finally, the Malus law is used to determine and convert the absorption axis. This solution is faster than the prior art method of continuously observing the intensity of light passing through the polarizer to be measured by rotating a polarizer to determine its absorption axis. The measurement can be completed within one second, and the measurement time for different absorption axis angles is the same. In addition, the influence of the rotating mechanism on the measurement effect in the prior art measurement method can be eliminated, thereby simplifying the measurement process.

Description

Technical Field

[0001] The invention belongs to the field of optical detection, and in particular relates to a method for quickly measuring the absorption axis of a polarizer. Background Art

[0002] Polarizer is an important optical film, mainly used in the displays of electronic products. Each liquid crystal display requires two polarizers, the lower polarizer is used to convert the light beam generated by the backlight source into polarized light, and the upper polarizer is used to analyze the polarized light after being electrically modulated by the liquid crystal to produce light and dark contrast, thereby producing a display image. As an important component of the display, knowing the absorption axis of the polarizer is a very important link, because the accurate absorption axis angle needs to be known to determine the cutting direction. If the absorption axis angle is not measured accurately, resulting in the wrong cutting direction, it will greatly affect the performance of the optical film, and in severe cases will cause the display image to be dark, blurred, or even no picture to be displayed.

[0003] Currently, the absorption axis of a polarizer is measured by placing a rotatable polarizer in front of the polarizer to be tested. The photoelectric signal that is emitted from the polarizer through the rotating polarizer is continuously collected, and the absorption axis of the polarizer is obtained based on the characteristics of the polarizer. This measurement process takes a long time, ranging from a dozen seconds to dozens of seconds for a polarizer. The measurement time for different absorption axis angles varies greatly, resulting in low overall efficiency. Summary of the Invention

[0004] In view of the above, the present invention provides a method for quickly measuring the absorption axis of a polarizer, which can realize fast online measurement of the absorption axis of a polarizer.

[0005] The specific technical solution is as follows.

[0006] A method for quickly measuring the absorption axis of a polarizer, characterized by:

[0007] Step 1: Obtain completely unpolarized light: convert natural light into completely unpolarized light through a collimator and a depolarizer in sequence;

[0008] Step 2: Irradiate completely unpolarized light onto the polarizer to be tested: the light is converted into linearly polarized light after passing through the polarizer to be tested, and its polarization state is represented by the Jones vector as E. Where E0 is the complex amplitude of the light wave;

[0009] Step 3: The light emitted from the polarizer to be tested passes through a multi-point analyzer: the multi-point analyzer is composed of single-point analyzers with different known absorption axis angles. Let one of the single-point analyzers be a reference analyzer. Let the angle between the absorption axes of the polarizer to be tested and the reference analyzer be θ0, and θ0 be in the range of [0°, 90°]. The other single-point analyzers in the multi-point analyzer and the reference analyzer form absorption axis angles θ1, θ2, and θ3, respectively.

[0010] Step 4: The receiver receives the optical signal transmitted by the multi-point analyzer and converts it into multiple electrical signals I1, I2, and I3 reflecting the amount of light energy, where I1 = I(θ0 + θ1), I2 = I(θ0 + θ2), and I3 = I(θ0 + θ3);

[0011] Step 5: According to the relationship between the absorption axis and the light intensity signal between the single-point analyzers in the multi-point analyzer, the angle θ0 between the absorption axis of the polarizer to be tested and the absorption axis of the reference analyzer is obtained;

[0012] Step 6: Based on the obtained θ0 and Malus's law, the angle θ0′ between the absorption axis of the polarizer to be tested and the reference analyzer in the range of [-90°, 0°] is obtained.

[0013] Furthermore, the polarization characteristics of a single point in a multi-point analyzer are expressed as the Jones matrix J,

[0014]

[0015] In the above formula, t / / represents the amplitude transmittance along the principal axis of the linear polarizer, ε represents the extinction ratio of the polarizer, and the Jones vector E of the single-point outgoing light in the multi-point analyzer c =JE.

[0016] Furthermore, the light intensity signal received by the receiver is I(θ)=E c 2 ,Right now

[0017] Furthermore, I1, I2, and I3 are substituted into the light intensity signal I(θ) formula, where I1, I2, and I3 are measured values, to obtain θ0.

[0018] The method for quickly measuring the absorption axis of a polarizer of the present invention is to set a combination of single-point analyzers with different known absorption axis angles in the emitting direction of the polarizer to be measured. Preferably, only three analyzers with specific absorption axes are needed. A specific electrical signal is obtained through each single-point analyzer, and multiple specific light intensity values ​​can be obtained at one time. The relationship between the angle between the absorption axis of the analyzer and the absorption axis of the polarizer to be measured can be calculated by substituting the obtained multiple light intensity values ​​into a formula. Because the absorption axis of the analyzer is known, the absorption axis of the polarizer to be measured can be quickly obtained, and finally the conversion can be judged by Malus's law. This scheme is faster than the existing method of judging and measuring the absorption axis by continuously observing the light intensity passing through the polarizer to be measured by rotating the polarizer. The absorption axis of the polarizer to be measured can be obtained by calculation by obtaining three light intensity values ​​at one time, and the measurement can be completed within one second. The measurement time for different absorption axis angles is the same, and the influence of the rotating mechanism on the measurement effect in the existing measurement method can be eliminated, making the measurement process simpler.

[0019] Additional aspects and advantages of the present invention will be further set forth in the following description, and in part will be obvious from the following description, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 The figure shows the process flow of the rapid measurement method of the polarizer absorption axis:

[0022] Figure 2 Shown is a schematic diagram of the optical path of the polarizer absorption axis rapid measurement method;

[0023] Figure 3 The figure shows the composition diagram of the multi-point analyzer;

[0024] Among them, 1-light source, 2-collimating lens, 3-depolarizer, 4-polarizer to be tested, 5-multi-point analyzer, 6-receiver, 7-reference analyzer, 8-other analyzers. DETAILED DESCRIPTION

[0025] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0026] Reference Figure 1-Figure 2In this embodiment, the method for rapidly measuring the absorption axis of a polarizer includes the following steps: Step 1: Obtaining completely unpolarized light: Natural light is converted into completely unpolarized light through a collimator lens 2 and a depolarizer 3. The collimator lens 2 converts the divergent light from the light source 1 into collimated light. The depolarizer 3 converts the collimated light into completely unpolarized light, eliminating any polarized light from the light source that could affect the final measurement result.

[0027] Step 2: Irradiate completely unpolarized light onto the polarizer 4 to be tested: the light is converted into linearly polarized light by the polarizer 4 to be tested, and its polarization state is represented by the Jones vector as E. Where E0 is the complex amplitude of the light wave.

[0028] Step 3: The light emitted from the polarizer 4 to be tested passes through the multi-point analyzer 5: The multi-point analyzer 5 is composed of single-point analyzers with different known absorption axis angles. Assume that one of the single-point analyzers is the reference analyzer. The angle between the absorption axes of the polarizer to be tested and the reference analyzer is θ0, and θ0 is in the range of [0°, 90°]. The other single-point analyzers in the multi-point analyzer and the reference analyzer form absorption axis angles θ1, θ2, and θ3, respectively, as shown in FIG. Figure 3 In the multi-point analyzer 5 structure with at least 3 analyzer combinations of specific absorption axes, when there are 3 analyzers, one of θ1, θ2, and θ3 here can be understood as the angle between the reference analyzer and itself, that is, 0°. In the multi-point analyzer 5 structure with other analyzer combinations of more than 3 specific absorption axes, the angle between the reference analyzer and itself can be ignored. It is advocated that there are at least 3 angle parameters for calculation.

[0029] The polarization characteristics of a single point in a multi-point analyzer are represented by the Jones matrix J.

[0030]

[0031] In the above formula, t / / represents the amplitude transmittance along the principal axis of the linear polarizer, ε represents the extinction ratio of the polarizer, and the Jones vector E of the single-point outgoing light in the multi-point analyzer c =JE.

[0032] Step 4: The receiver 6 receives the optical signal transmitted by the multi-point polarizer 5 and converts it into multiple electrical signals I1, I2, I3 reflecting the amount of light energy, where I1 = I(θ0+θ1), I2 = I(θ0+θ2), and I3 = I(θ0+θ3).

[0033] The light intensity signal received by the receiver is I(θ)=E c 2 ,Right now

[0034] Step 5. Based on the relationship between the absorption axis and the light intensity signal between the single-point analyzers in the multi-point analyzer, obtain the angle θ0 between the absorption axis of the polarizer to be tested and the reference analyzer. Substitute I1, I2, and I3 into the light intensity signal I(θ) formula to obtain the following three equations:

[0035]

[0036] I1, I2, and I3 are measured values, and θ1, θ2, and θ3 are known values. Therefore, θ0 can be obtained through these three equations, that is, the angle between the absorption axis of the polarizer to be measured and the reference analyzer at [0°, 90°].

[0037] Step 6: To determine the angle between the absorption axis of the polarizer to be tested and the reference analyzer at [-90°, 0°], according to Malus's law I(θ)=I0cos 2 From θ, we can see that the light intensity signal value changes periodically. By comparing I1, I2, and I3 for logical judgment and the obtained θ0, we can determine the angle θ0′ between the absorption axis of the polarizer under test and the reference analyzer in the range [-90°, 0°]. Finally, we can determine that the angle between the absorption axis of the polarizer under test and the reference analyzer absorption axis of the multi-point analyzer is in the range [-90°, 90°].

[0038] Although specific embodiments of the present invention have been described in detail with reference to exemplary embodiments thereof, it should be understood that a variety of other modifications and embodiments may be devised by those skilled in the art that fall within the spirit and scope of the principles of the present invention. Specifically, reasonable variations and improvements may be made in the arrangement of components and / or dependent combinations within the scope of the foregoing disclosure, the accompanying drawings, and the claims without departing from the spirit of the present invention. Except for variations and improvements in components and / or arrangement, the scope thereof is defined by the appended claims and their equivalents.

Claims

1. A method for quickly measuring the absorption axis of a polarizer, characterized by: Step 1: Obtain completely unpolarized light: convert natural light into completely unpolarized light through a collimator and a depolarizer in sequence; Step 2: Irradiate completely unpolarized light onto the polarizer to be tested: the light is converted into linearly polarized light after passing through the polarizer to be tested, and its polarization state is represented by the Jones vector as E. Where E0 is the complex amplitude of the light wave; Step 3: The light emitted from the polarizer to be tested passes through a multi-point analyzer: the multi-point analyzer is composed of single-point analyzers with different known absorption axis angles. Let one of the single-point analyzers be a reference analyzer, let the angle between the absorption axes of the polarizer to be tested and the reference analyzer be θ0, θ0 is in the range of [0°, 90°], and the absorption axis angles θ1, θ2, and θ3 are formed between the other single-point analyzers in the multi-point analyzer and the reference analyzer, respectively. Step 4: The receiver receives the optical signal transmitted by the multi-point analyzer and converts it into multiple electrical signals I1, I2, and I3 reflecting the amount of light energy, where I1 = I(θ0 + θ1), I2 = I(θ0 + θ2), and I3 = I(θ0 + θ3); Step 5: According to the relationship between the absorption axis and the light intensity signal between the single-point analyzers in the multi-point analyzer, the angle θ0 between the absorption axis of the polarizer to be tested and the absorption axis of the reference analyzer is obtained; Step 6: Based on the obtained θ0 and Malus's law, the angle θ0′ between the absorption axis of the polarizer to be tested and the reference analyzer in the range of [-90°, 0°] is obtained.

2. The method for rapid measurement of polarizer absorption axis according to claim 1, characterized in that: The polarization characteristics of a single point in a multi-point analyzer are represented by the Jones matrix J. In the above formula, t / / represents the amplitude transmittance along the principal axis of the linear polarizer, ε represents the extinction ratio of the polarizer, and the Jones vector E of the single-point outgoing light in the multi-point analyzer c =JE.

3. The method for rapid measurement of polarizer absorption axis according to claim 2, characterized in that: The light intensity signal received by the receiver is I(θ)=E c 2 , Right now 4. The method for rapid measurement of polarizer absorption axis according to claim 3, characterized in that: Substitute I1, I2, and I3 into the light intensity signal I(θ) formula, where I1, I2, and I3 are measured values, and calculate θ0.

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