JP2007285873A - Optical characteristics measuring method, optical characteristics measurement system, and stage used for system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical characteristic measuring method, an optical characteristic measurement system, and a stage used for the system, capable of stably performing high-accuracy measurement. <P>SOLUTION: This system has a light source 101 for supplying light; a polarizer 103 and an analyzer 110 that is irradiated with the light from the light source 101; an automatic rotary stage 105 provided between the polarizer 103 and the analyzer 110, for placing a sample 107 thereon; a motor 113 for making the automatic rotary stage 105 rotate at a prescribed angle; a light-receiving sensor 111 for receiving the light transmitted through the analyzer 110; and a calculation control part 112 for calculating the optical characteristics of the sample 107, based on the quantity of light received by the light-receiving sensor 111 and a rotation angle of the automatic rotary stage 105. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical property measuring method, an optical property measuring system, and a stage used in this system.

  Conventionally, the molecular orientation characteristics of an analyte, for example, a polymer film (substantially non-orientated film (for example, in-plane retardation is 20 nm or less) such as an oriented film such as a retardation film or an original film) A polarization microscope is used to measure the direction and angle of the optical axis (hereinafter referred to as “orientation angle” as appropriate) (see, for example, Patent Document 1). In measurement using a polarizing microscope, first, the polarizer and the analyzer are adjusted to a so-called crossed Nicol state. Next, the subject is placed between the polarizer and the analyzer. Then, the subject is rotated around a predetermined axis. As the subject rotates, the amount of light passing through the analyzer changes. The orientation angle of the subject is measured based on the change in the amount of light and the amount of rotation.

JP 2001-356276 A

  However, in the configuration of the prior art, rotating the subject and detecting a change in the amount of light depend on the manual operation of the measurer (operator). As a result, there arises a problem that the measurement result varies depending on the skill level of the measurer.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical property measurement method, an optical property measurement system, and a stage used in this system, which can stably perform highly accurate measurement. .

  In order to solve the above-described problems and achieve the object, according to the first aspect of the present invention, there is provided an adjustment step for adjusting the polarizer and the analyzer to a predetermined position, and the coverage between the polarizer and the analyzer. An irradiation step for irradiating the sample with light, a rotation step for rotating the subject at predetermined angles based on the drive signal, a light amount detection step for detecting the amount of light transmitted through the analyzer, and the detected light amount It is possible to provide an optical property measurement method characterized by including an optical property calculation step for calculating the optical property of the subject based on the predetermined angle.

  In addition, according to a preferred aspect of the present invention, it is desirable to further include a calculation step of detecting the light amount a plurality of times at a predetermined angle and calculating an average value of the plurality of light amounts.

  Further, according to a preferred aspect of the present invention, the light amount detection step, the calculation step, and the optical characteristic calculation step are respectively performed on the first state and the second state of the subject, and in the first state, It is desirable to further include a step of calculating the optical characteristic of the subject based on the calculated first optical characteristic and the second optical characteristic calculated in the second state.

  According to the second aspect of the present invention, a light source that supplies light, a polarizer and an analyzer that are irradiated with light from the light source, and a polarizer and an analyzer are provided, and a subject is placed thereon. Based on the stage, the rotation driving unit that rotates the stage at a predetermined angle, the light receiving unit that receives the light transmitted through the analyzer, the amount of light received by the light receiving unit, and the rotation angle of the stage It is possible to provide an optical characteristic measurement system including an arithmetic control unit that calculates an optical characteristic of a subject.

  According to a preferred aspect of the present invention, the arithmetic control unit calculates an average value of a plurality of measurement amounts of light received by the light receiving unit, and based on the average value and a predetermined angle, the optical of the subject is calculated. It is desirable to calculate the characteristics.

  Further, according to the third aspect of the present invention, the apparatus has a base portion for placing the subject and a contact portion for abutting the subject, and a part of the contact portion is formed on the base portion. A stage characterized by being formed to be embedded can be provided.

  According to another aspect of the present invention, a light source that supplies light, a polarizer and an analyzer that are irradiated with light from the light source, and a polarizer and an analyzer are provided, and a subject is placed thereon. Based on the above-described stage, a rotation driving unit that rotates the stage at a predetermined angle, a light receiving unit that receives light transmitted through the analyzer, an amount of light received by the light receiving unit, and a rotation angle of the stage Thus, an optical characteristic measurement system having an arithmetic control unit for calculating the optical characteristic of the subject can be provided.

  According to the present invention, it is possible to provide an optical characteristic measurement method, an optical characteristic measurement system, and a stage used for this system that can stably perform highly accurate measurement.

  Embodiments of an optical property measuring method, an optical property measuring system, and a stage used in the system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 shows a schematic configuration of an optical property measurement system 100 according to an embodiment of the present invention. The optical property measurement system 100 is a system for measuring the orientation angle of a polymer film (an oriented film such as a retardation film or a non-oriented film such as a raw film), for example. For this reason, a polymer film such as a retardation film can be used as the sample 107. In FIG. 1, each component is shown in a disassembled state for easy understanding.

  Illumination light from the light source 101 is collected by the collector lens 102. The condensed light illuminates the sample 107 placed on the sample setting table 106 by the condenser lens 104. The sample mounting table 106 is configured to be rotatable around the optical axis AX by an automatic rotation stage 105. For convenience of explanation, it is assumed that the rotation axis of the automatic rotation stage 105 and the optical axis AX coincide with each other. The motor 113 rotationally drives the automatic rotation stage 105 according to the drive signal from the arithmetic control unit 112.

  Light from the illuminated sample 107 is collected by the objective lens 108. Then, an enlarged image of the sample 107 is formed by the objective lens 108. A measurer (not shown) observes the magnified image through an eyepiece (not shown).

  A polarizer 103 is disposed in the optical path between the collector lens 102 and the condenser lens 104. An analyzer 110 is disposed in the optical path between the objective lens 108 and the magnified image.

  The polarizer 103 and the analyzer 110 are generally arranged in a so-called crossed Nicol state in which the transmission directions are orthogonal to each other. Further, as the optical characteristics, for example, when measuring the birefringence of the sample and its axial direction, the compensator 109 can be disposed between the polarizer 103 and the analyzer 110. As the compensator 109, a λ / 4 wavelength plate, a Babinet Soleil compensator, or the like can be used. The compensator 109 is configured to be inserted into and removed from the optical path.

  When the sample 107 is not placed on the sample mounting table 106, the visual field is dark. In this state, the sample 107 is placed on the sample mounting table 106. Then, the sample 107 is rotated around the optical axis AX according to a procedure described later. Thereby, the direction of the orientation angle of the sample 107 changes. For this reason, the amount of light received by the light receiving sensor 111 changes. By measuring the minimum value of this change in light amount, the orientation angle of the sample 107 can be obtained.

  Next, a measurement procedure using the optical characteristic measurement system 100 will be described. FIG. 2 is a flowchart showing a setting procedure for starting measurement. In step S201, the arithmetic control unit drives the automatic rotation stage 105 (hereinafter referred to as “automatic stage” as appropriate in the flowchart) so as to reach a predetermined origin position.

  In step S202, the automatic rotation stage 105 is further rotated to the measurement start position. In step S203, the angle of the analyzer 110 is adjusted. In step S <b> 204, the arithmetic control unit 112 determines whether or not the signal intensity of the light amount detection by the light receiving sensor 111 is the lowest. When the determination result of step S204 is false (No), step S203 is repeated. When the determination result in step S204 is true (Yes), in step S205, preparation for the start of measurement is completed. Steps S201 to S205 correspond to the adjustment step.

  In the adjustment step described above, an example in which the analyzer 110 is rotated has been described. However, the present invention is not limited to this, and if the angular relationship between the polarizer 103 and the analyzer 110 can be relatively changed, only the polarizer 103 is driven to rotate, and both the polarizer 103 and the analyzer 110 are rotated. Any of driving may be used.

  FIG. 3 is a flowchart showing a procedure for measuring the optical characteristics of the sample 107. In the irradiation step of step S301, the sample 107 is placed on the sample mounting table 106 prepared by the above-described procedure. Detailed configurations of the sample 107 and the sample mounting base 106 will be described later. Here, the first surface (front surface) of the sample 107 is placed on the sample mounting table 107 with the objective lens 108 side facing. This state corresponds to the first state of the sample 107. Then, measurement is started.

  In the rotation step of step S <b> 302, the arithmetic control unit 112 outputs a drive signal for rotating the automatic rotation stage 105 in the + (plus) direction at predetermined angle increments, for example, every 0.05 °, to the motor 113. The motor 113 rotates the automatic rotation stage 113 in accordance with the drive signal.

  In step S303, the light receiving sensor 111 detects the amount of light transmitted from the analyzer 110 at a predetermined angular position. The arithmetic control unit 112 stores an output corresponding to the light amount value in a memory (not shown). Here, it is desirable to perform light quantity detection a plurality of times in a state where the automatic rotation stage 105 is at the same position. For example, measurement is performed 1000 times, and outputs V1 to V1000 (for example, voltage values) corresponding to the respective amounts of received light are obtained.

  Next, the total output from the output V1 to the output V1000 is divided by the number of measurements 1000 to calculate the average output Vave. As described above, by sampling the signal at high speed and performing the averaging process, an accurate average output Vave can be obtained when the light intensity signal is not constant (fluctuates).

  In step S304, the arithmetic control unit 112 determines whether the obtained light reception signal, that is, the average output Vave is equal to or greater than a set threshold value. Here, as the “threshold value”, a voltage value of 4.0 (V) in FIG. 5 described later can be used. When the voltage exceeds the threshold, valid data cannot be obtained even if measurement is continued further. At this time, the threshold is set to interrupt (end) the measurement. Such a threshold value can be arbitrarily set by the measurer as long as it is less than the dynamic range of the light receiving sensor. The measurement can be completed efficiently by the threshold value. When the determination result of step S304 is false, the process proceeds to step S305. If the determination result at step S304 is true, the process proceeds to step S306.

  In step S305, the calculation control unit 112 determines whether the rotation position of the automatic rotation stage 105 is within the set range. When the determination result of step S305 is true, the process returns to step S302. If the determination result at step S305 is false, the process proceeds to step S306.

  In the rotation step of step S 306, the arithmetic control unit 112 outputs a drive signal for rotating the automatic rotation stage 105 to the motor 113 in the − (minus) direction at predetermined angle increments. The motor 113 rotates the automatic rotation stage 113 in accordance with the drive signal. Here, the minus direction refers to a direction opposite to the plus direction. In addition, how to take the plus direction and the minus direction (definition of the direction) is arbitrary.

  In step S307, the light receiving sensor 111 detects the amount of light transmitted from the analyzer 110 at a predetermined angular position. The arithmetic control unit 112 stores an output corresponding to the light amount value in a memory (not shown). Here, as in step S303, it is desirable to perform light quantity detection a plurality of times in a state where the automatic rotation stage 105 is at the same position.

  In step S308, the calculation control unit 112 determines whether the obtained light reception signal, that is, the average output Vave is equal to or greater than a set threshold value. When the determination result of step S308 is false, the process proceeds to step S309. Further, when the judgment result at step S308 is true, the process proceeds to step S310.

  In step S309, the arithmetic control unit 112 determines whether the rotation position of the automatic rotation stage 105 is within a set range. When the determination result of step S309 is true, the process returns to step S306. If the determination result at step S309 is false, the process proceeds to step S310. In step S310, the automatic rotation stage is driven to rotate to the position of the lowest angle. Here, the position of the “minimum angle” refers to the angle of the automatic rotation stage 105 when the detected voltage value is minimum. At the lowest angle position, the optical signal has the lowest intensity. For example, when the orientation angle is 0 degree, the minimum angle corresponds to 0 degree.

  It is desirable to perform the procedure from the above-described steps S301 to S310 to the sample 107 the following two times in the first state and the second state. FIG. 4 is a flowchart showing a further measurement procedure. First, in step S401, the first surface of the sample 107, for example, the surface thereof is placed on the sample mounting table 106 in a state where the surface is opposed to the objective lens 108 (first state). In step S402, in the first state, measurement is performed according to the procedure from steps S301 to S310 described above.

  Next, in step S <b> 403, the second surface of the sample 107, for example, the back surface is placed on the sample setting table 106 in a state where the second lens is opposed to the objective lens 108 (second state). In step S404, in the second state, measurement is performed according to the procedure from steps S301 to S310 described above.

  Then, the difference between the measurement result (first optical characteristic) calculated in the first state and the measurement result (second optical characteristic) calculated in the second state is divided by two. Thereby, an absolute value can be easily obtained without special consideration of the positional relationship between the angle of the automatic rotation stage 105 and the polarization axis of the polarizer 103 and the analyzer 110. In addition, if the relationship between the angle of the automatic rotation stage 105 and the above-described polarization axis is set in advance, only the measurement in the first state (first surface, front surface) or the second state (second surface, back surface) is performed. You can go.

  FIG. 5 is a diagram in which the output values obtained are plotted while the automatic rotation stage 105 is rotated at predetermined angles. Note that each plotted point corresponds to the average output Vave described above. The horizontal axis in FIG. 5 is the angle (unit: °) of the automatic rotation stage 105, and the vertical axis is the voltage value (unit: V) corresponding to the output of the light receiving sensor 111. In FIG. 5, the rotation angle of the automatic rotation stage 105 when the voltage value becomes the minimum value is obtained. This value corresponds to the direction of the light distribution axis.

  Here, the minimum value of the voltage value can be calculated from the extreme value obtained by interpolating the data points with a curve. Thereby, the minimum value can be calculated more accurately. Examples of the interpolation method include polynomial approximation, but are not particularly limited.

  Next, returning to FIG. 1, the sample mounting table 106 will be described. The sample mounting base 106 has a base portion 106a for placing the sample 107 and a contact portion 106b for abutting the sample 107. A part of the contact portion 106b is formed to be embedded in the base portion 106a.

  In this embodiment, a retardation film is measured as the sample 107. Such a sample usually has a shape cut into a rectangular shape. Then, one side of the sample 107 is brought into contact with the contact portion 106 b of the sample setting table 106.

  In the configuration of the sample mounting table according to the prior art, the contact portion is screwed to the upper surface of the planar base portion, for example. With such a configuration, there arises a problem that the thin film film as the sample enters the gap between the base portion and the contact portion. Such “rolling” of the sample 107 causes a sample installation error. A sample installation error leads to an error (variation) in measurement results.

  In the automatic rotation stage 106 in this embodiment, the sample 107 does not get caught between the base 106a and the contact portion 106b. For this reason, it is possible to reduce the penetration of the sample 107 by the sample mounting table 106 having an inexpensive and simple configuration. Note that the base portion 106a and the contact portion 106b may be integrally molded.

  Next, the effect of the present invention will be described. FIG. 6 shows a measurement result when the same measurer repeatedly measures the same sample. The horizontal axis in FIG. 6 indicates the number of measurements, and the vertical axis indicates the orientation angle (unit: °). FIG. 7 is a similar diagram obtained by a conventional method. As is apparent from a comparison between FIG. 6 and FIG. 7, it can be seen that the measurement results obtained by this system have extremely high repeatability.

  FIG. 8 shows the results of measurement using this system by a person who is trained (for example, an expert) and a person who is not trained (for example, an unskilled person or a beginner). The horizontal axis in FIG. 8 indicates the measurement result (orientation angle) of a person who has received training, and the vertical axis indicates the measurement result (orientation angle) of a person who has not received training. FIG. 9 is a similar view obtained by the conventional method.

  In FIG. 8, the correlation coefficient value between the “measurement result of the person who has been trained” and “the measurement result of the person who has not been trained” is 0.95. In contrast, the similar correlation coefficient value in the conventional method is 0.73. A larger correlation coefficient value means that there is less variation in both measurement results. That is, according to the present system, stable measurement can be performed without depending on an expert or non-expert. For example, according to the present system, the measurement accuracy is a repeatability accuracy of ± 0.1 ° and a measurement accuracy of ± 0.3 °.

  As described above, in the present invention, the rotation accuracy of the stage can be improved by automating the driving of the stage. In addition, the above-described sample setting table 106 can reduce sample setting errors. Furthermore, by calculating the average of a plurality of measurement values, the accuracy of signal reading by the measurer can be improved. Furthermore, an absolute value can be easily obtained by measuring the first surface and the second surface. The present invention can take various modifications without departing from the spirit of the present invention.

  As described above, the optical property measurement system according to the present invention is useful when measuring the direction of the light distribution axis of a retardation film or a polymer film.

It is a figure which shows schematic structure of the optical characteristic measuring system which concerns on the Example of this invention. It is a flowchart which shows the procedure of the optical characteristic measuring method in an Example. It is another flowchart which shows the procedure of the optical characteristic measuring method in an Example. It is another flowchart which shows the procedure of the optical characteristic measuring method in an Example. It is a figure which shows the measurement result in an Example. It is a figure which shows the repetition precision of this invention. It is a figure which shows the repetition precision in a prior art example. It is a figure which shows the correlation of the measurement result of the expert and non-skilled person in this invention. It is a figure which shows the correlation of the measurement result of the expert and non-skilled person in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Optical characteristic measurement system 101 Light source 102 Collector lens 103 Polarizer 104 Condenser lens 105 Automatic rotation stage 106 Sample installation stand 106a Base part 106b Contact part 107 Sample 108 Objective lens 109 Compensator 110 Analyzer 111 Light receiving sensor 112 Calculation control part 113 motor

Claims (7)

An adjusting step for adjusting the polarizer and the analyzer to a predetermined position;
An irradiation step of irradiating a subject between the polarizer and the analyzer with light;
A rotation step of rotating the subject by a predetermined angle based on a drive signal;
A light amount detection step for detecting the amount of light transmitted through the analyzer;
An optical characteristic measurement method comprising: an optical characteristic calculation step of calculating an optical characteristic of the subject based on the detected light amount and the predetermined angle.   The optical characteristic measuring method according to claim 1, further comprising a calculation step of detecting a light amount a plurality of times at the predetermined angle and calculating an average value of the plurality of light amounts. The light amount detection step, the calculation step, and the optical characteristic calculation step are performed for the first state and the second state of the subject, respectively.
The method further includes the step of calculating the optical characteristic of the subject based on the first optical characteristic calculated in the first state and the second optical characteristic calculated in the second state. The optical property measuring method according to claim 2, wherein A light source for supplying light;
A polarizer and an analyzer irradiated with light from the light source;
A stage provided between the polarizer and the analyzer, on which a subject is placed;
A rotation drive unit that rotates the stage at predetermined angles;
A light receiving portion for receiving light transmitted through the analyzer;
An optical characteristic measurement system comprising: an arithmetic control unit that calculates an optical characteristic of the subject based on a light amount of light received by the light receiving unit and a rotation angle of the stage.   The arithmetic control unit calculates an average value of a plurality of measurement light amounts of light received by the light receiving unit, and calculates an optical characteristic of the subject based on the average value and the predetermined angle. 5. The optical property measuring system according to claim 4, A base for placing a subject;
A contact portion for abutting the subject,
Part of the contact portion is formed so as to be embedded in the base portion. A light source for supplying light;
A polarizer and an analyzer irradiated with light from the light source;
The stage according to claim 6, wherein the stage is provided between the polarizer and the analyzer, and the subject is placed thereon.
A rotation drive unit that rotates the stage at predetermined angles;
A light receiving portion for receiving light transmitted through the analyzer;
An optical characteristic measurement system comprising: an arithmetic control unit that calculates an optical characteristic of the subject based on a light amount of light received by the light receiving unit and a rotation angle of the stage.

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