JP4568064B2 - Optical anisotropic axis measuring device - Google Patents

Description

The present invention relates to an optical anisotropic axis measurement equipment of the optical element, in particular the orientation axis and the twist angle of the liquid crystal panel, the polarization axis of the polarizing film, accurate measurement of the optical anisotropic axis, such as the slow axis of the retardation film And it is suitable for manufacture of a high quality liquid crystal panel based on this measurement.

Liquid crystal displays are widely used as display devices such as personal computers, information terminals, and television receivers. The liquid crystal display is formed by combining a plurality of members having optical anisotropic axes. A schematic diagram illustrating an example of a liquid crystal display is shown in FIG. As shown in FIG. 17, a liquid crystal display is formed by combining a plurality of members having an optical anisotropic axis, and the plurality of members having an optical anisotropic axis are mainly composed of a liquid crystal panel, a polarizing film, and a retardation film. The And it is very important in the manufacturing process of a liquid crystal display to manage the optical anisotropic axis of these members. Conventionally, methods for measuring the optical anisotropic axis of polarizing films and liquid crystal panels have been proposed.

  In FIG. 17, a liquid crystal panel 120 is configured by sandwiching a liquid crystal 122 in a bonding gap between a first glass substrate (also referred to as an upper glass substrate) 125 and a second glass substrate (also referred to as a lower glass substrate) 127. The An alignment film is formed at each interface between the upper glass substrate 125 and the liquid crystal 122 and between the lower glass substrate 127 and the liquid crystal 122, but the illustration is omitted. The liquid crystal 122 is oriented in the direction indicated by the orientation axis 121 by these orientation films, that is, an orientation regulating force is applied. Hereinafter, the first glass substrate (or the upper glass substrate) and the second glass substrate (or the lower glass substrate) are also simply referred to as the first substrate, the second substrate, or both.

  On the upper side (display side) of the liquid crystal panel 120, a composite film 111 in which the upper polarizing film 101A and the retardation film 112 are bonded is installed. The upper polarizing film 101 </ b> A has a polarization axis 102 </ b> A, and the retardation film 112 has a delay axis 113. A lower polarizing film 101 </ b> B is installed on the lower side of the liquid crystal panel 120. The lower polarizing film 101B has a polarizing axis 102B. And the backlight 171 is provided in the back surface of the lower polarizing film 101B. In the measurement described below, the upper polarizing film 101A and the lower polarizing film 101B are collectively referred to as the polarizing film 101.

  For such a plurality of members, for example, as a technique for measuring the polarization axis angle of the polarizing film, a sample (in the present invention, a sample to be measured, a measurement sample, a polarizing film, a retardation film, a liquid crystal panel: a liquid crystal panel: Measured with a polarizing microscope having a polarizer and an analyzer sandwiching a mounting stage (stage) on which a measurement object having optical anisotropy such as an alignment film, etc. is mounted. A technique used as an apparatus is known. The measurement procedure by this method is as follows.

  First, a polarizing film, which is a measurement sample, is set on the stage, and the polarizer is rotated while detecting the transmitted light amount, and an angle at which the transmitted light amount is minimized is searched. The angle at which the amount of transmitted light is minimum is a state where the polarizing axes of the polarizer and the polarizing film are orthogonal (crossed Nicols). Therefore, since the polarization axis angle of the polarizer is known, the polarization axis angle of the polarizing film can be obtained.

  Next, a conventionally known method for measuring the optical anisotropic axis of a liquid crystal panel will be described. Here, as an example, an IPS (In Plane Switching) type liquid crystal panel used for TV applications with a wide viewing angle will be described. In IPS liquid crystal panels, nematic liquid crystal is homogeneously aligned between two upper and lower glass substrates. Retardation occurs due to the difference in refractive index between the orthogonal direction and parallel direction to the molecular axis of the liquid crystal. With the same optical anisotropic axis. Here, the molecular axis direction of the liquid crystal is defined as the alignment axis.

As a method for measuring the alignment axis of a liquid crystal panel, a method using a measuring device including a polarizing microscope having a polarizer and an analyzer arranged with a stage on which a liquid crystal panel is mounted is known. The measurement procedure by this method is as follows.

First, the polarizer and analyzer of the polarization microscope are set in a crossed Nicol state. Next, a liquid crystal panel, which is a measurement object, is installed between the polarizer and the analyzer. When the relative angle between the polarizer and the analyzer is changed while the relative polarization axis angle is maintained, an angle at which the amount of transmitted light is minimized appears. This angle is the orientation axis angle of the liquid crystal panel.

As related to this type of prior art, Patent Document 1 describes the alignment axis of a liquid crystal panel using the measurement principle described above in order to improve the optical anisotropic axis matching accuracy between the liquid crystal panel and the polarizing film. And the direction of the transmission axis of the polarizing film are identified, and after attaching the liquid crystal panel and the polarizing film so that those axes are aligned, a method of cutting the outer shape of the polarizing film using a laser is disclosed. Conventionally, the image quality of a liquid crystal display has been improved using a technique as described in Patent Document 1.
JP 2003-107452 A

In recent years, the size of liquid crystal displays has increased, and large liquid crystal televisions larger than 28 inches have appeared, and the image quality of large liquid crystal televisions has been improved to antagonize the image quality of televisions using cathode ray tubes. In addition, the size of the mother glass for manufacturing the liquid crystal panel constituting the liquid crystal display is steadily increasing, and a mother glass substrate exceeding 2 meter square is also planned.

A major contribution to improving the image quality of large LCD TVs is the management of the alignment axis of the liquid crystal panel and the polarization axis of the polarizing film. For this purpose, it is important to measure the alignment axis of the alignment axis control panel in which liquid crystal is dropped on the mother glass that has been subjected to the alignment treatment, and another mother glass is bonded, and to measure the alignment axis of the LCD TV size after cutting. is there. On the other hand, with respect to a polarizing film to be attached to a liquid crystal panel, an increase in area is progressing in the manufacturing process. Therefore, it is important to control the polarization axis at the stretched original fabric stage and also manage the polarization axis at the stage of cutting the original film into the product size of the liquid crystal panel.

  In addition, in order to improve the image quality of liquid crystal displays in the future, all optical anisotropic axes constituting the liquid crystal display, that is, the alignment axis and twist angle of the liquid crystal panel, the polarization axis of the polarizing film, and the slow axis of the retardation plate It is necessary to increase the accuracy, and it is also necessary to improve the in-plane variation of each optical anisotropic axis that becomes conspicuous as the area of the liquid crystal display increases. Furthermore, it is also important for improving the image quality of the liquid crystal display to improve the image quality of the liquid crystal display by improving the accuracy of all the optical anisotropic axes and performing the bonding in consideration of the in-plane distribution of the optical anisotropic axes.

  However, since the conventional technique is a measurement method mainly composed of a polarizing microscope, it has been difficult to realize high-precision in-plane distribution measurement of the optical anisotropic axis with respect to the mechanical position of a large area measurement object. . In addition, the method disclosed in Patent Document 1 is a method in which a polarizing film and a liquid crystal panel are bonded together based on the optical anisotropic axis angle result at a measurement point. We are not thinking about increasing the accuracy of the axis. Therefore, the present invention aims to solve the following five problems.

The first problem is to provide a high-precision optical anisotropic axis measurement method corresponding to a large area measurement object. In the conventional optical anisotropic axis angle measurement method, the liquid crystal panel and the polarizing film, which are measurement objects, are placed on the stage with the ends of the polarizing film butted against a positioning pin or a flat surface. For this reason, the measurement result of the optical anisotropic axis varies depending on the cutting accuracy of the liquid crystal panel and the polarizing film and the installation accuracy on the stage, and it has been difficult to realize highly accurate measurement. Therefore, the displacement of the optical anisotropic axis cannot be accurately measured with respect to the alignment mark or the cut end face, and feedback to the manufacturing process is performed to improve the accuracy of each optical anisotropic axis with respect to the alignment mark or the cut end face. There was a problem in improving the in-plane distribution.

In addition, since the measurement object is moved in the two-dimensional plane and the measurement is performed, there is a problem that an area four times larger than the measurement object becomes an operating area of the measurement object, and the measurement apparatus becomes large. In particular, the place where the optical anisotropic axis angle is measured at the stage of the mother glass substrate and the place where the polarizing axis measurement of the polarizing film at the original film stage is often performed in a clean room. (Footprint) needs to be reduced.

A first object of the present invention is to provide a technique for measuring the alignment axis of a liquid crystal panel and the polarization axis of a polarizing film easily and with high accuracy and a small footprint.

The second problem of the present invention is to provide a highly accurate slow axis measurement technique for a retardation film with a polarizing film. Conventionally, there has been a method for measuring the slow axis of a retardation film, but it has not been possible to measure with high accuracy and simplicity. The second object of the present invention is to provide a technique for measuring the slow axis of a retardation film with a polarizing film with high accuracy and simplicity.

A third problem of the present invention is that a substrate (hereinafter also referred to as a TFT substrate) formed by forming a pixel circuit such as a thin film transistor or a driving circuit on a lower glass substrate and a substrate (hereinafter referred to as a TFT substrate) on which a color filter is formed. And a color filter substrate or a CF substrate) and a method for measuring a twist angle of a liquid crystal panel composed of liquid crystal with high accuracy. Conventionally, there has been a method for measuring the twist angle of a liquid crystal panel, but it has not been possible to measure with high accuracy and simplicity. Even if high-precision alignment axis measurement of the liquid crystal panel, which is the first issue, is possible, in order to accurately determine which direction of the alignment regulation force of the TFT substrate or the color filter substrate is shifted, the high-precision of the liquid crystal panel Twist angle measurement is required. A third object of the present invention is to provide a technique for measuring the twist angle of a liquid crystal panel with high accuracy and ease.

The fourth problem of the present invention is to optimize the assembly process of the TFT substrate and the color filter substrate. In the case of assembling a TFT substrate and a color filter substrate, since a method for measuring the alignment axis and the twist angle with high accuracy, which is expressed by the alignment treatment of the alignment film on each substrate, has not been established, There was a problem that there was no method for mass production after confirming that the twist angle converged to the control value. The fourth object of the present invention is to optimize the alignment process of the TFT substrate and the color filter substrate by applying the above-described method for measuring the alignment axis and the twist angle with high accuracy.

The fifth object of the present invention is to optimize the assembly process of the liquid crystal display in which the alignment axis and twist angle of the liquid crystal panel in the liquid crystal display, the polarization axis of the polarizing film, and the slow axis of the retardation film are managed with high accuracy. There is.

In order to solve the above problems, the present invention employs the following means. That is,
(1) In order to solve the first problem, a mounting table (hereinafter also referred to as a stage) on which a material having optical anisotropy as a measurement object is mounted, an alignment mark provided on the measurement object, or a measurement object It comprises a detection means (end recognition means) that is preferably an image recognition means having a CCD camera for detecting an end, a light source, a polarizer and an analyzer capable of controlling the attitude, and a light intensity recognition means. The stage has a light transmission part at an arbitrary position, and the measurement optical system passes the light from the light source through the polarizer and the light transmission part of the stage, passes through the substance having optical anisotropy, and the analyzer. After passing through, the apparatus was configured to enter the light intensity recognition means.

And the edge part and attitude | position of a substance which have optical anisotropy are recognized by the image recognition means provided in said apparatus. An optical anisotropic axis measurement of a substance having optical anisotropy was performed based on the recognition result. In addition, the measurement object is fixed to the stage, and the optical system composed of the light source and the light intensity recognition means moves in the plane of the measurement object to measure the optical anisotropic axis at an arbitrary position. . Furthermore, a calibration plate for which the absolute axis was obtained in advance was equipped so that accuracy could be guaranteed at the start of the system.

(2) In order to solve the second problem, the present invention provides a stage on which a composite optical anisotropic film of a polarizing film and a retardation film, which is a measurement object, is mounted, and a mark or edge detection of the measurement object. Means, a light source, a polarizer whose attitude can be controlled, the stage, a retardation plate whose analyzer can control the attitude, an analyzer, and a light intensity recognition means. The stage has a light transmission portion at an arbitrary position, and the measurement optical system passes light from the light source through the polarizer and the light transmission portion of the stage, through the composite optical anisotropic film, and a retardation plate And after passing through the analyzer, it was configured to enter the light intensity recognition means.

And the edge part and attitude | position of a composite optically anisotropic film are recognized by the image recognition means provided in this apparatus. Based on the recognition result, the polarization axis and the delay axis of the composite optically anisotropic film were measured. Furthermore, a calibration plate for which the absolute axis was obtained in advance was equipped so that accuracy could be guaranteed at the start of the system.

(3) In order to solve the third problem, the present invention provides a stage on which a liquid crystal panel as a measurement object is mounted, a mark or end detection means for the measurement object, a light source, a polarizer capable of controlling the attitude, and It comprises an analyzer and light intensity recognition means. The stage has a light transmission part at an arbitrary position, and the measurement optical system passes the light from the light source through the polarizer and the light transmission part of the stage, passes through the liquid crystal panel, and passes through the analyzer. The apparatus was configured to be incident on the intensity recognition means. And the edge part and attitude | position of a liquid crystal panel were recognized with the image recognition means provided in this apparatus, and the twist angle of the liquid crystal panel was measured on the basis of this recognition result.

(4) In order to solve the fourth problem, the present invention formulates a liquid crystal panel production plan from the management number of the optical anisotropic film to be bonded and the optical anisotropic axis angle measurement result, Determining the orientation axis angle and orientation axis angle control value of the TFT substrate (the substrate having a pixel circuit composed of thin film transistors and a drive circuit) and the color filter substrate (substrate having a plurality of color filters formed thereon, CF substrate). Then, the alignment process is performed on the TFT substrate and the color filter substrate, the relative positions of the TFT substrate and the color filter substrate are aligned, the liquid crystal is sandwiched, and the liquid crystal panel is formed by forming a predetermined gap by overlapping the liquid crystal panel. Then, the twisting angle is measured, and the alignment processing conditions of the TFT substrate and the color filter substrate are adjusted by branching whether the alignment axis is within the control value. After applying the readback, to produce a liquid crystal panel, and a substance having an optical anisotropy and paste it into the liquid crystal panel.

In order to solve the fifth problem, the present invention has an optical anisotropy after recording a management number of a substance having an optical anisotropy such as a liquid crystal panel, a polarizing film or a retardation film to be superimposed. Measure each optical anisotropic axis angle with respect to the mark or edge provided on the substance, save the optical anisotropic axis angle measurement result together with the substance management number, measure those substance management number and optical anisotropic axis angle From the results, the optical anisotropic axis of each substance was superposed at a desired relative angle.

According to the present invention, an optical anisotropic axis angle with respect to an end face or a mark of a measurement object can be measured with high accuracy. As a result, the measurement error due to the variation in installation of the measurement object on the stage is eliminated, and the optical anisotropic axis with respect to an arbitrary reference position can be measured even for a substance having optical anisotropy having a distorted end face. Furthermore, since the measurement optical system moves relative to the measurement object, the floor area occupied by the apparatus or equipment, the so-called footprint, becomes smaller than when the measurement optical system is fixed and the stage is moved, and the measurement object has a large area. It became possible to respond to the change. In the present invention, since the apparatus has a plate having optical anisotropy for calibration, the accuracy can always be ensured. In the apparatus of the present invention, the polarizer, analyzer, and retardation plate rotate with high accuracy, so that the polarization axis angle and retardation axis angle of the retardation film with the polarizing film and the twist angle of the liquid crystal panel can be measured with high accuracy. Became.

The TFT that constitutes the liquid crystal panel can be produced from the optical anisotropic axis angle measurement result of the optical anisotropic film to be bonded using the high-precision optical anisotropic axis measurement method of the present invention. The alignment axis angle of the substrate and the color filter substrate and the control value of the alignment axis angle can be determined. It is possible to confirm whether the panel is sandwiched between the TFT substrate and the color filter substrate, and the panel with the liquid crystal sandwiched between the control values is measured by using the method of measuring the alignment axis and the twist angle with high accuracy according to the present invention. It was. If it is not within the control value, the liquid crystal panel can be manufactured after feeding back the alignment processing conditions of the TFT substrate and the color filter substrate, so that the alignment processing process of the TFT substrate and the color filter substrate can be optimized. became.

According to the optical anisotropic alignment method of the present invention, it is possible to eliminate those having an optical anisotropic axis outside the standard before superposition. In addition, since each member has performance variation, it is possible to select an optimum combination for superposition from each optical anisotropic axis angle measurement result and to superimpose at an optimum angle. Furthermore, since the performance of the product after superposition can be predicted from the optical anisotropic axis angle result of each member and the rank can be classified, the inspection items after superposition can be reduced.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings of the examples.

1A and 1B are diagrams for explaining a first embodiment of a polarization axis measuring apparatus according to the present invention. FIG. 1A is a front view and FIG. 1B is a side view. FIG. 2 is a top view of the polarization axis measuring apparatus shown in FIG. The polarizing film measurement method and apparatus of Example 1 will be described with reference to FIGS.

1 and 2, an illumination optical system (light source unit) 30 that is movable in the X direction on a linear rail 31 that is a light source unit moving mechanism installed on the surface plate 20 is provided. A rotating polarizer unit 41 installed in the rotating mechanism is provided so as to move together with the light source unit 30. A sample mounting base (hereinafter referred to as a stage) 21 provided with a light transmitting portion 23 is installed on the upper portion. The stage 21 is movable in the Y direction on a drive system (stage moving mechanism) 22 composed of two parallel running rails.

In addition, the stage 21 is equipped with an adsorption function (not shown) for fixing a measurement sample (a sample to be measured such as a polarizing film or a liquid crystal panel) to prevent the measurement sample from being displaced or lifted during measurement. I am doing so. At least three alignment pins 24 are erected on the stage 21, and are parallel with two pins at the back when viewed from the front, and are aligned in the horizontal direction with one pin on the right front side. The position of the alignment pin 24 is variable so as to match the size of the measurement sample (here, a polarizing film). A CCD camera, which is a light intensity recognition means (light intensity recognition unit) 50 supported by an angle, is installed on the stage 21. Since a CCD camera is used for the light intensity recognition unit, when a foreign substance is placed on the surface of the sample in the measurement area, the measurement is performed in an area excluding that part. This detailed image analysis will be described later.

Further, in order to obtain the in-plane distribution of the polarization axis angle in the measurement area, the measurement area was divided, and a function for obtaining the polarization axis angle in each divided area was added. If these functions are not required, it is also possible to use a device that detects light intensity, such as a power meter, as the light intensity recognition means. The light intensity recognition unit 50 moves in the X direction along a rail 51 provided at an angle. Further, the light source unit 30, the rotating polarizer unit 41, and the light intensity recognition unit 50 are assembled as a series of measurement optical systems, and move while maintaining their relative positions when moving in the X direction. The measurement optical system can be measured at an arbitrary place on the polarizing film 101 mounted on the stage 21 by moving the measurement optical system in the X direction and moving the sample mounting table 21 in the Y direction.

An end portion and a mark detection CCD camera (end recognition camera) 25 are installed. The camera 25 is movable in the X direction along a rail installed at an angle, and a measurement sample placed on the stage 21. The mechanical position of the (polarizing film) 101 is detected. A standard polarizer 26 with a known polarization axis angle is installed on the stage 21. Alternatively, like the polarizing film 101, the standard polarizer 26 is mounted on the stage 21 so that the polarization axis angle can be measured. The standard polarizer 26 is measured to calibrate the polarizer angle and light quantity. In FIG. 3, in order to show the layout of the light transmission part 23, a part of the polarizing film 101 is cut out.

FIG. 3 is a diagram showing a measurement optical system in Example 1 of the polarization axis measuring apparatus according to the present invention. FIG. 3A shows a non-polarized light source 1, a filter 5 for controlling the light quantity and wavelength, a light source unit 30 comprising a condenser lens 2, a polarizer 7 installed in a rotating mechanism, and a zoom by sandwiching a stage 21. This is a measurement optical system composed of a lens 10 and a CCD camera 9 as light intensity recognition means. The light source 1 is generally a lamp. In this configuration example, the light is transmitted through the stage 21 by the light transmitting portion 23 as shown in FIGS. The light transmitting portion 23 may not be a hole, and there is no problem in the configuration of the present invention as long as the characteristics of transmitted light do not change. For example, it is possible to use a stage 21 whose entire surface or a part is made of a material having a small optical anisotropy such as quartz glass.

Further, as shown in FIG. 3B, an analyzer 8 installed in a rotation mechanism may be provided instead of the polarizer 7. Alternatively, both the polarizer 7 and the analyzer 8 may be provided as shown in FIG. However, in the case of the configuration example shown in FIG. 3 (c), a function capable of rotating while maintaining the relative position between the polarizer 7 and the analyzer 8 is required. Hereinafter, a measurement procedure using the polarization axis measuring apparatus shown in FIGS. 1 to 3 will be described.

FIG. 4 is a diagram for explaining a measurement procedure in the first embodiment of the polarization axis measuring apparatus according to the present invention. First, the apparatus is started up (step 201), the angle of the polarizer is calibrated (step 202), and then the polarization axis of the polarizing film is measured (step 203). After the measurement is completed, the apparatus is turned off (step 204).

FIG. 5 is a diagram for explaining the detailed procedure of the polarizer angle calibration step at the start of FIG. 5, first, the measurement optical system is moved to the position of the standard polarizer 26 for angle calibration installed on the stage 21 shown in FIG. 2 (step 211), and the polarization axis of the standard polarizer 26 is measured (step 214). ). Since the polarization axis angle of the standard polarizer 26 is known, the polarizer angle of the measurement optical system is calibrated from the result. About the measuring method of a polarizing axis, it is the same as that of the measuring method of the polarizing film mentioned later. Thus, in the polarization axis measuring apparatus of the present invention, the polarization axis management of the polarizer is not performed as a regular calibration as in the conventional polarization axis measuring apparatus, but the angle of the polarizer is calibrated at the start of each operation. The reliability of the result is improved.

FIG. 6 is a diagram for explaining a detailed procedure for measuring the polarization axis of the polarizing film in FIG. 4 using the optical system in FIG. First, the stage is moved forward (step 231), and the polarizing film, which is a measurement sample, is mounted on the sample mounting base 21 while pressing the end portion against the positioning pin 24 (step 232). The polarizing film is adsorbed (step 233), and the position of the polarizing film is fixed. The stage is pulled in (step 234), and the edge recognition camera measures the edge of the polarizing film (step 234), and calculates the mechanical position with respect to the sample mounting base 21 (step 236). In addition, the calculation method of the mechanical position with respect to the stage of a polarizing film is mentioned later.

The measurement optical system is moved to the first measurement position (step 237), an image of the measurement region is acquired (step 238), and it is determined whether there is a foreign object or a defect (step 239). This determination method will be described later. If there is a foreign object or a defect, an area excluding the abnormal part is selected for measurement (step 240). Thereafter, the polarizer is rotated by a certain angle until the final point is reached (step 241), an image is acquired (step 243), and an in-plane signal intensity average value is obtained (step 244) is repeated.

When the final point angle is reached, the angle at which the average value of the signal intensity is minimized is obtained (step 246), and the polarization axis angle at the measurement point is obtained. Details of this measurement operation will be described later. During this process, the relative position of the measurement optical system and the stage is changed and moved to another measurement position (step 247). Therefore, the above measurement operation is repeated, and a desired measurement position set in advance is automatically measured.

When measurement is completed at all measurement points, the measurement optical system is returned to the initial position (step 249), the stage is moved forward (step 250), the adsorption of the polarizing film is released (step 251), and the measurement sample is replaced. (Step 252). Here, a method of rotating the polarizer with respect to the measurement sample and obtaining the angle at which the light quantity minimum value is obtained has been described. However, when the absorption axis directions of the polarizer 7 and the polarizing film 101 coincide, the light quantity maximum value is obtained. From this, the absorption axis of the polarizing film can also be determined by obtaining the angle at which the light quantity is maximized.

Up to this point, the measurement method using the optical system of FIG. 3 (a) has been described. However, in the case of using the optical system of FIG. 3 (b), the operation of the polarizer is replaced with an analyzer and the above procedure is performed. A similar result can be obtained by performing the above. In addition, when the optical system of FIG. 3 (c) is used, the reference axes of the polarizer and the analyzer are set, and the polarizations of the polarizer and the analyzer are kept parallel (parallel Nicols). Similar results can be obtained by performing child operations.

Next, a method for detecting the mechanical posture of the polarizing film with respect to the stage will be described. FIG. 7 is a schematic diagram of an image taken by the edge recognition camera in the polarization axis measurement of the first embodiment of the present invention. The edge recognition camera 25 moves along the edge of the polarizing film 101, which is a measurement sample mounted on the stage 21, and captures an image at an arbitrary edge position of the sample. The schematic diagram of an image when the edge part of the polarizing film 101 is detected is shown to (a) (b) (c) of FIG. A hatched portion 64 in FIG. 7 is a polarizing film portion, and reference numeral 61 indicates an end portion thereof. In each image, an average line 62 with respect to the unevenness of the edge 61 is drawn, and the coordinates of the intersection of the average line 62 and the center line 63 of the image (Δx _i , Δy _i ). If the origin coordinates of each image with respect to the stage 21 are (x _i , y _i ), the end coordinates are (x _i + Δx _i , y _i + Δy _i ), and these two or more arbitrary end images can be used to The position of the polarizing film 101 with respect to the stage 21 is recognized by obtaining the position coordinates and performing linear approximation.

In the case of FIG. 7 (a), the coordinates of the polarizing film end (Δx _a, Δy _a), the origin coordinates of each image with respect to the stage 21 is (x _a, y _a), the coordinates of the end ( x _a + Δx _a , y _a + Δy _a ). In the case of FIG. 7B, the coordinates of the edge of the polarizing film are (Δx _b , Δy _b ), the origin coordinates of each image with respect to the stage 21 are (x _b , y _b ), and the coordinates of the edges are Becomes (x _b + Δx _b , y _b + Δy _b ). Similarly, in the case of FIG. _7C , the coordinates of the polarizing film end are (Δx _c , Δy _c ), the origin coordinates of each image with respect to the stage 21 are (x _c , y _c ), The coordinates are (x _c + Δx _c , y _c + Δy _c ).

In addition, this operation recognizes the posture of the polarizing film 101 with respect to the stage 21 in the same manner when a position detection mark is provided on the polarizing film 101 instead of the end of the polarizing film to detect it. it can. A method for recognizing the posture of the measurement sample by mark detection will be described later in the third embodiment. Data relating to the orientation of the polarizing film is reflected in the measurement result of the polarization axis measured thereafter.

FIG. 8 is an explanatory diagram of image data acquired by the light intensity detection means of the optical system shown in FIG. 3, and FIG. 8 (a) is a schematic diagram of the image. FIG. 8B is a diagram showing a histogram of the signal intensity of each pixel in FIG. In a polarizing film having a polarization axis that is uniform to some extent in the plane, the histogram of the normal part 71 having no foreign matter or defect in the measurement region is a smooth curve having one maximum value that can be approximated by a Gaussian distribution as indicated by a peak 74. is there. However, when the light-absorbing substance 72 is attached to the measurement region of the polarizing film 101, a peak 75 appears at a signal intensity position lower than the main peak 74 in the histogram. On the other hand, when the polarizing film is scratched or has a portion 73 to which a light-transmitting substance having optical anisotropy is attached, the histogram generally has a signal intensity position higher than the main peak 74 of the normal portion 71. A peak 76 appears at. In the apparatus of the present invention, the average signal intensity is calculated by automatically excluding the abnormal pixel and the pixel peripheral portion where the signal intensity deviates from the Gaussian distribution.

Next, a polarization axis angle measuring method used in the polarization axis measuring apparatus according to the first embodiment of the present invention will be described. FIG. 9 is an explanatory diagram of the average signal intensity when measuring the polarization axis using the polarization axis measuring apparatus of the present invention. FIG. 9C shows a measurement optical system. In this measurement optical system, the polarizer 7 has a rotation mechanism, and the polarization angle applied to the polarizing film 101 changes by rotating the polarization axis of the polarizer 7. When the polarizer 7 is rotated with respect to the polarizing film 101 while detecting the transmitted light amount with the CCD camera 9 through the zoom lens 10 and the signal intensity of the transmitted light amount detection with respect to the angle is plotted, a graph shown in FIG. 9A is obtained.

In this way, using the phenomenon that the signal intensity changes depending on the angle, first, while detecting the transmitted light amount, for example, the polarizer 7 is rotated at a rough interval in the angle range of 210 ° to fit the sine curve. A rough angle θ ₁ 77 that minimizes the amount of transmitted light is obtained. If a certain degree of orientation axis angle can be determined in advance, the above rough measurement operation is not necessary. Thereafter, the transmitted light is detected while rotating the polarizer at a fine angle interval before and after the amount of transmitted light is minimized. FIG. 9B shows a plot of signal intensity versus angle for the measurement result. A minimum value is obtained by fitting a curve such as a quadratic curve to the plot of FIG. The angle θ ₂ 88 that minimizes the amount of transmitted light is the angle at which the polarization axis of the polarizer 7 and the polarization axis of the polarizing film 101 become crossed Nicols. Since the polarization axis angle of the polarizer is known, the polarization axis angle θ ₂ of the polarizing film as the measurement object can be obtained.

In addition, although mentioned here about the method of rotating a polarizer by the angular step of equal intervals, the method of detecting transmitted light while rotating continuously rather than the step of equal intervals, the steepest gradient method (mountain climbing method), etc. Similar results can be obtained if the minimum value can be obtained. Since the orientation of the polarizing film with respect to the stage has already been measured, the polarization axis angle with respect to the end (or a mark described later) of the polarizing film can be calculated. The in-plane distribution of the polarization axis angle can be measured by performing the above measurement operation at a different measurement position by changing the relative position between the measurement optical system and the polarizing film.

FIG. 10 is a diagram for explaining an example of the operation image displayed on the image display means provided in the control device in the first embodiment of the polarization axis measuring apparatus according to the present invention. FIG. 10 shows an image 81, a histogram 84, and a measurement graph 87 of the current measurement area so that the measurer can constantly monitor the measurement state. In addition, when there is an abnormal part 82, the measurement is performed by excluding the part including the peripheral part, so the area 83 to be excluded is clearly indicated. Since a peak 86 different from the main peak 85 also appears on the histogram 84, it indicates which part is excluded. The display 88 shows the measurement result at the measurement point where the measurement has been completed so far for the in-plane polarization axis of the polarizing film currently being measured. The angle of the arrow in the display 88 is a deviation angle from the reference axis.

The display 89 shows the maximum value, minimum value, average value, and in-plane variation of the actual measurement values of the shaft angle measurement results. Further, if these measurement results exceed a preset management value, for example, It is displayed in red. In the display 90, the transmitted light intensity at the time of crossed Nicol at each measurement point is shown using contour lines, and the in-plane extinction ratio distribution is shown. Further, the history display 91 can be used to view information on the polarizing film 101 measured so far, and the polarizing film 101 is automatically ranked according to the preset performance based on the respective measurement results. The results are also shown.

Example 2 of this invention demonstrates the method of measuring the axial direction of each film about the composite film of retardation film and a polarizing film. The compound optical anisotropic axis measuring apparatus according to the second embodiment has basically the same configuration as that of FIGS. 1 and 2 described in the first embodiment, but the configuration of the measurement optical system is different from that of the first embodiment. Therefore, here, the measurement optical system unique to Example 2 in the polarization axis measurement apparatus will be described in detail.

FIG. 11 is a diagram illustrating an optical system in the composite optical anisotropic axis measuring apparatus according to the second embodiment of the present invention. When expressed simply as an optical system, FIG. 11A is an optical system similar to FIG. 3A, and FIG. 11B is an optical system similar to FIG. 3C. In Example 2, as shown in FIG. 11C, a non-polarized light source 1, a light source unit 30 comprising a filter 5 and a condenser lens 2 for controlling the light quantity and wavelength, and a polarizer 7 installed in a rotating mechanism. Further, with the stage 21 having the light transmission part 23 interposed therebetween, the quarter wavelength plate 12 installed in the rotation mechanism, the analyzer 8 (rotation analyzer 43 described later) installed in the rotation mechanism, and the zoom lens 10 This is a measurement optical system composed of a light intensity recognition unit having a CCD camera 9 as light intensity recognition means.

The analyzer 8 and the quarter-wave plate 12 can be selectively or detachable from the optical path. When only the quarter-wave plate 12 is removed, the optical system shown in FIG. When the ¼ wavelength plate 12 is removed, the optical system shown in FIG. One embodiment of a switching mechanism of these optical systems is shown in FIG.

  FIG. 12 is a diagram illustrating switching between the light intensity recognition unit and the quarter-wave plate switching unit according to the second embodiment of the present invention. FIG. 12A shows the optical system of FIG. 11A in which the light intensity recognition unit is switched to the second CCD camera 19 and both the analyzer 8 and the quarter wavelength plate 12 are removed from the optical path. FIG. 12B shows the optical system of FIG. 11B in which the light intensity recognition unit is switched to the CCD camera 9 side and the analyzer is placed in the optical path. FIG. 12C shows the optical system of FIG. 11B in which a quarter wavelength plate is inserted in the optical path of FIG.

  The light intensity recognition unit 50 has a structure having a CCD camera 9 in which an analyzer 8 rotated by a rotary drive unit 42 is arranged on an optical path, and a second CCD camera 19 having neither an analyzer nor a quarter-wave plate. . Also, the quarter-wave plate switching unit 50B shown in FIG. 12 has a quarter-wave plate that is rotated inside by the rotation drive unit 42, and the quarter-wave plate from the state of FIG. By sliding the switching unit, the quarter-wave plate is inserted on the optical path of the CCD camera 9, and the result is as shown in FIG. Thereby, the optical system of FIG.11 (b) and FIG.11 (c) is switched.

In FIG. 12, the code | symbol 111 shows the composite film of a phase difference film and a polarizing film, this composite film 111 is mounted on the stage 21, and the optical anisotropic axis | shaft is measured. In the measurement to be described later, FIGS. 12A, 12B, and 12C are switched.

  The stage 21 is provided with the same light transmission portion 23 as in the first embodiment. In addition, although the quarter-wave plate 12 is used in the optical anisotropic axis measuring apparatus of the second embodiment, it may not be a quarter-wave plate. An isotropic substance can also be used.

The measurement procedure using the composite optical anisotropic axis measurement apparatus of Example 2 is the same as that shown in FIG. The contents of angle calibration at the start of business (step 202 in FIG. 4) and normal measurement (step 203 in FIG. 4) are different from the polarization axis measurement of the polarizing film described in the first embodiment. Hereinafter, the angle configuration and normal measurement at the start of the composite optical anisotropic axis measurement device of Example 2 will be described.

FIG. 13 is a diagram for explaining the procedure for starting polarizer angle calibration of the compound optical anisotropic axis measuring apparatus according to the second embodiment of the present invention. In FIG. 202). First, the measurement optical system is moved to the position of the standard polarizer 26 for angle calibration installed on the stage 21 shown in FIG. 2 (step 211), and switched to the camera 9 (light intensity recognition unit switching, step 212). The optical system is configured as shown in FIG. 11A, and the transmitted light amount is measured while rotating the analyzer with respect to the standard polarizer 26 (measure standard polarizer—step 214), and the angle at which the transmitted light amount is minimized. Ask.

Since the polarization axis angle of the standard polarizer 26 is known, the polarization axis angle of the polarizer 7 is calibrated from the measurement result (setting the reference axis of the polarizer—step 215). Here, the standard polarizer is measured using the same method as the polarization axis measuring method described above. Thereafter, the measurement optical system is moved to the light transmission part (step 216), and after switching to the camera 9 having the analyzer (step 217), the transmitted light amount is detected while rotating the analyzer with respect to the polarizer 7 (step 217). 218). As a result, the reference axis of the analyzer is set at an angle (crossed Nicols) that minimizes the transmitted light (step 219).

In the state where the polarizer 7 and the analyzer are in the crossed Nicols state, the quarter wavelength plate 12 is attached as shown in FIG. 12C (step 220), and the transmitted light amount is changed while the quarter wavelength plate 12 is rotated. It detects (step 221) and searches for an angle at which the amount of transmitted light is minimum. The angle is an angle at which the delay axis of the quarter wavelength plate 12 coincides with the polarization axis of the polarizer 7, and this is set as the reference axis of the quarter wavelength plate 12 (step 222). Thereafter, the camera 9 having the analyzer is switched to the second camera 19 having neither the analyzer nor the quarter wavelength plate (step 223), and the measuring optical system is returned to the initial position (step 224).

The analyzer and the quarter-wave plate 12 may be detachable while maintaining the reference axis, and the camera 9 and the second camera 19 may be configured by the same camera. Here, a method for calibrating the angle of the polarizer 7 with the standard polarizer is described. However, even if the angle of the analyzer is calibrated first using the standard polarizer instead of the polarizer 7, the measurement apparatus of the present embodiment is used. There is no problem in nature. Thus, the reliability of the measurement results is improved by performing the axial angle calibration of the polarizer 7, the analyzer, and the quarter-wave plate at the start of work each time.

Next, a method for measuring the polarization axis angle and the delay axis angle of the composite film of the polarizing film and the retardation film will be described. First, the polarization axis of the polarizing film is measured with the optical system shown in FIG. 11A (arrangement of FIG. 12A). The procedure for measuring the polarization axis is the same as the method shown in FIG. 6 described in the first embodiment. However, when the composite film is placed on the stage (step 232 in FIG. 6), the polarizing film side is set to the light source unit side. Put. After obtaining the polarization axis angle of the polarizing film by the operations up to step 246 in FIG. 6, the flow proceeds to the flow in FIG. 14 in order to measure the retardation axis of the retardation film.

FIG. 14 is a diagram illustrating a first example of a normal measurement procedure of the composite optical anisotropic axis measurement device according to the second embodiment of the present invention. If it is determined in step 245 of FIG. 6 that the determination end point angle has been reached, first, the polarization axis of the polarizer 7 is aligned with the polarization axis of the polarizing film obtained previously (step 253). In step 253, the polarizer 7 may be removed. Next, the light intensity recognition unit is switched from the state shown in FIG. 12A to the state shown in FIG. 12B (step 254), and the measurement optical system is configured as shown in FIG. An image is acquired by the optical system (step 255), and an in-plane signal intensity average is obtained (step 256).

Thereafter, the analyzer is rotated by a predetermined angle (step 263), an image is acquired again (step 255), and an in-plane signal intensity average value is obtained (step 256). The operations of Steps 255, 256, and 263 are repeated until the set final point angle is reached. If it is determined that the determination end point angle has been reached (Step 258), the angle at which the transmitted light amount is minimized is found (Step 267). If the measurement wavelength and retardation of the retardation film are clear, the retardation axis of the retardation film can be calculated from the angle of deviation from the polarization axis angle of the polarizing film at the angle at which the amount of transmitted light is minimum (step 265). Thereafter, the light intensity recognition unit is switched (step 266), and the process goes to step 246 in FIG.

Next, a method for measuring the delay axis angle when the retardation of the retardation film is unknown will be described. FIG. 15 is a diagram showing a second example of the normal measurement procedure of the compound optical anisotropic axis measurement apparatus according to Embodiment 2 of the present invention. The composite film is placed on the stage with the polarizing film side down, and the polarization axis angle of the polarizing film is measured with the optical system shown in FIG. 11A (state of FIG. 12A). The measurement procedure of the polarization axis is the same as the method shown in FIG. 6 described in the first embodiment. After obtaining the polarization axis angle of the polarizing film by the operation up to step 245 in FIG. 6, the process proceeds to the flow in FIG. 15 in order to measure the delay axis of the retardation film.

First, the polarization axis of the polarizer 7 is matched with the polarization axis of the polarizing film obtained previously (step 253). In step 253, the polarizer may be removed. Next, the light intensity recognition unit is switched from the state shown in FIG. 12A to the state shown in FIG. 12B (step 254), and the measurement optical system is configured as shown in FIG. 11B. An image is acquired by this optical system (step 255), and an in-plane signal intensity average is obtained (step 256). Thereafter, the analyzer is rotated by a certain angle (step 257), an image is acquired again (step 255), and an in-plane signal intensity average value is obtained (step 256). If it is determined that the final point angle has been reached (step 258), a quarter-wave plate is mounted so that the delay axis coincides with the polarization axis of the polarizing film (step 259), and the measurement optical system is shown in FIG. The configuration is as follows. An image is acquired (step 260).

In this optical system, the analyzer is rotated by a fixed angle until the final point angle is reached (step 263), an image is acquired (step 260), and an in-plane signal intensity average is obtained (step 261). . When it is determined that the determination end point angle has been reached (step 264) and the above operation is completed, the least square method is used from the transmitted light intensity data for the angles obtained in the routines of steps 255 to 258 and steps 260 to 265. The Stokes parameter is obtained, the delay axis angle and retardation in the measurement region are obtained (step 266), and the process goes to step 246 in FIG.

Since the posture of the composite film with respect to the stage has already been measured, the polarization axis angle and the delay axis angle of the composite film with respect to the mark or the edge are calculated. The method for obtaining the posture of the sample by edge detection has been described in the first embodiment. A method for obtaining the posture of the sample by detecting the mark will be described in a third embodiment. During the calculation processing of the polarization axis angle and the delay axis angle, the state shown in FIG. 12C is switched to the state shown in FIG. 12A (step 266 in FIG. 15), and the relative position between the measurement optical system and the stage is changed. Move to another measurement position (step 246 in FIG. 6). Thereafter, the above measurement operation is repeated for a desired measurement position set in advance. When the measurement at all the measurement points is completed, the measurement optical system returns to the initial position (step 249 in FIG. 6), the stage moves forward (step 250 in FIG. 6), and the adsorption of the polarizing film is released (FIG. 6). 6 step 251), the measurement sample is exchanged (step 252 in FIG. 6).

FIG. 16 is a diagram illustrating an example of an image displayed on the image display unit provided in the control device of the compound optical anisotropic axis measurement device according to Example 2 of the compound optical anisotropic axis measurement device according to the present invention. The image display means shows an image 81 of the measurement area being measured, a histogram 84, and a measurement graph 87 so that the measurer can always monitor the measurement status. In addition, when there is an abnormal part 82 in the image 81, the measurement is performed by excluding the part including the peripheral part, so that the area 83 to be excluded is clearly shown in the image. Also on the histogram 84, the abnormal part 82 appears at a peak 86 different from the main peak 85, so it indicates which part is excluded.

The polarization axis angle display 88 shows the measurement results at the measurement points where the measurement has been completed so far for the in-plane polarization axis angle of the polarizing film currently being measured. The angle of the arrow in the display 88 is a deviation angle from the reference axis. The display 89 shows the actual maximum value, minimum value, average value, and in-plane variation of the axial angle measurement result, and is displayed in red when a predetermined management value is exceeded. In the display 90, the transmitted light intensity distribution when the polarization axes of the polarizer 7 and the polarizing plate at each measurement point are crossed Nicols is shown using contour lines. This contour line shows the in-plane extinction ratio distribution.

The display so far is the same as the measurement result screen of the polarizing film described in Example 1, but in Example 2, the measurement object is a composite film in which a polarizing film and a retardation film are bonded together. Since the measurement result of the retardation film is displayed in addition to the measurement result, this will be described next. The display 95 shows the measurement results at the measurement points where the measurement has been completed so far for the in-plane delay axis angle of the composite film currently being measured. The display 96 shows the actual measurement maximum value, minimum value, average value, and in-plane variation of the delay axis angle measurement result, and is displayed in red when a preset management value is exceeded. In the display 97, the in-plane distribution of retardation at each measurement point is shown using contour lines. Further, the history display 98 can be used to view information on the composite film measured so far, and the composite film can be read according to the preset performance based on the measurement results of the polarization axis angle, the delay axis angle, and the retardation. Automatically ranked.

As Example 3 of the present invention, a method of measuring the delay axis direction of a substance having uniaxial optical anisotropy (retardation) will be described. The measurement target includes a retardation plate, a liquid crystal panel, and the like. Here, a measurement method of a delay axis of the liquid crystal panel, that is, a liquid crystal alignment direction (herein referred to as an alignment axis) will be described as an example. The liquid crystal panel to be measured was formed as follows.

18A and 18B are diagrams for explaining a method for forming an alignment film of a liquid crystal panel. FIG. 18A is a schematic diagram of a flexographic printing process used for alignment film application, and FIG. 18B is a glass substrate 125 after coating film formation. It is a top view of Fig.18 (a) which shows an example. FIG. 18C is a schematic diagram of the step of imparting the orientation regulating force, and FIG. 18D is a plan view of FIG. Here, description will be made assuming that four liquid crystal panels are taken from a glass substrate 125 which is a mother substrate (mother glass).

First, as shown in FIG. 18A, an alignment film solution is applied on a glass substrate 125 by flexographic printing. A pattern is formed on the printing plate 163 carried on the plate cylinder so that the solution is coated on the display area of the liquid crystal panel. A solution supply roll 161 is in contact with the printing plate 163, and the alignment film solution is supplied from the solution supply roll 161 to the printing plate 163. A so-called doctor blade 160 is installed close to the surface of the solution supply roll 161 to control the film thickness of the alignment film solution supplied to the printing plate 163. The alignment film solution is applied onto the glass substrate 125 by bringing the printing plate 163 into contact with the glass substrate 125 and moving the glass substrate 125 in the direction of the arrow 125. After the application, the alignment film 123 is formed by baking and curing at a temperature of 200 ° C. or higher.

Then, as shown in FIG. 18C, the molecular axis of the liquid crystal is aligned in the rubbing direction 166 by moving the glass substrate 125 in the direction of the arrow 165 by contacting the alignment film 123 while rotating the rubbing roller 164 at a high speed. Applying alignment control force to align. Here, the alignment film uses a polyimide solution and imparts liquid crystal alignment regulating force by rubbing, but a liquid crystal alignment regulating force imparting method other than rubbing, such as an inorganic alignment film or polarized light irradiation, may be used. In this way, two glass substrates to which the liquid crystal alignment regulating force is given are prepared.

In Example 3, of the first and second glass substrates, the first glass substrate is a so-called array circuit substrate having a thin film transistor (TFT) for applying a voltage to each pixel, and the second glass substrate. The substrate is a so-called color filter substrate in which, for example, three color filters are formed, but either or both may be a glass substrate that does not include the above-described circuit or color filter (here, a TFT array). (Circuit and color filter not shown).

FIG. 19 is a diagram for explaining the development of the orientation axis due to the overlapping of the glass substrates. FIG. 19A is an explanatory diagram of bonding of the first glass substrate 125 and the second glass substrate 127, and a plan view is shown on the upper side and a sectional view is shown on the lower side. FIG. 19B is an explanatory view showing a state in which the individual liquid crystal panels 120 are divided from the two glass substrates bonded together by arranging the seals 124 around the regions to be the liquid crystal panels of the stacked glass substrates. The plane is shown on the left side, and the cross section is shown on the right side.

As shown in FIG. 19A, the second glass substrate is rubbed so that the rubbing direction 126 on the first glass substrate 125 side and the rubbing direction 128 on the second glass substrate 127 side are antiparallel. The glass substrate 127 is turned upside down so that the formation surfaces of the alignment films 123 are opposed to each other, and both substrates are held and overlapped. Here, a seal 124 is disposed by coating or the like around a region to be an individual liquid crystal panel on the first glass substrate 125 side, and the two stacked glass substrates are bonded to each other. At this time, a discontinuous portion serving as a liquid crystal injection port is formed in a part of the seal 124. In addition, in the case of supplying liquid crystal by a so-called dropping method, such a liquid crystal injection port is unnecessary.

Thereafter, the liquid crystal panel is divided into one liquid crystal panel or a plurality of liquid crystal panels, and liquid crystal is injected from a liquid crystal injection port and sandwiched between two glass substrates to form a liquid crystal panel as shown in FIG. In 19 (b), the alignment film is not shown. The rubbing direction 121 of the two glass substrates is not limited to being antiparallel as shown in the figure, and even if the rubbing direction is parallel or 90 ° twisted, the orientation axis can be similarly determined by the measuring method of the present invention. .

The alignment axis measuring apparatus according to the third embodiment is similarly described with reference to FIGS. 1 and 2 for explaining the first embodiment. However, since the configuration of the measurement optical system is different from that of the apparatus of the first embodiment, the measurement optical system of the apparatus of the third embodiment will be described in detail here.

  The measurement optical system of Example 3 is the same as that in which the sample 101 in FIG. 3A is replaced with 120 and the sample 101 in FIG. In Example 3, the transmitted light intensity angle dependency of the liquid crystal panel 120 is measured. Assume that a position detection mark (alignment mark) is attached to an appropriate position such as a peripheral portion of the liquid crystal panel 120.

The measurement procedure using the transmitted light intensity angle dependency measurement apparatus of Example 3 can be described with reference to FIG. 4, but in Example 3, angle calibration at the start of work (step 202 in FIG. 4) and normal measurement (FIG. 4). 4 is different from the measurement of the polarization axis of the polarizing film described in Example 1. The angle configuration and measurement at the start of the transmitted light intensity angle dependency measuring apparatus of Example 3 will be described.

FIG. 20 is a diagram illustrating a procedure for calibrating the polarizer angle at the start of work in Example 3 of the present invention. Similarly to the first embodiment, after adjusting the angle of the polarizer in steps 1001 to 1003 shown in FIG. 20, the analyzer is calibrated as follows using the calibrated polarizer. The measurement optical system is moved to the light transmission part 23 (step 1004), the analyzer is mounted (step 1005), the analyzer is rotated while the polarizer is fixed, and the angle dependence of the transmitted light intensity is measured. The angle at which the transmitted light intensity is minimized is obtained (step 1006), the analyzer is set to an angle at which the transmitted light intensity is minimized, and the relative position between the polarizer and the analyzer is fixed (step 1007).

By this method, the polarizer and the analyzer can be accurately placed in crossed Nicols (polarization axes are orthogonal). Here, a standard polarizer is used for calibration, but calibration with a substance having a uniaxial optical anisotropy whose delay axis angle is known (for example, a phase difference plate) is also possible. In that case, the polarizer and the analyzer are rotated by a method similar to the twist angle measurement described later to find the angle at which the transmitted light amount is minimized. The relative polarization axis angle between the polarizer and the analyzer at that time is 90 °. When this calibration method is used, the reference axis and crossed Nicols can be set without removing the polarizer and analyzer.

  FIG. 21 is a diagram illustrating a detailed procedure for measuring the alignment axis of the liquid crystal panel according to the third embodiment of the present invention. In FIG. 21, the stage 21 is first moved forward (step 231), and the liquid crystal panel 120, which is a measurement sample, is mounted on the stage 21 while pressing the end portion against the positioning pin 24 (step 232). The liquid crystal panel 120 is attracted to the stage 21 (step 233), and the position of the liquid crystal panel 120 is fixed. The stage is pulled in (step 234), the end and the mark recognition camera measure the mark written on the liquid crystal panel 120 (step 235), and the mechanical position with respect to the stage 21 is calculated (step 236). A method of calculating the mechanical position with respect to the stage of the liquid crystal panel by this mark detection will be described later.

  The measurement optical system is moved to the first measurement position (step 237), and an image of the measurement region is acquired (step 238). The same pattern is cut out in the measurement area, the measurement range is selected (FIG. 25-step 240), and the in-plane signal intensity average within the selected measurement range is obtained (FIG. 25-step 244). Details of this clipping method will be described later. Thereafter, the polarizer and the analyzer are simultaneously rotated by a certain angle while maintaining crossed Nicols until the final point is reached (step 242), an image is acquired (step 243), and an in-plane signal intensity average value is obtained (step 244). ), This operation is repeated until the determination end point angle is reached (step 245). The in-plane signal intensity average value is calculated from only information on the region of the same pixel pattern at each measurement point according to a predetermined pattern in a narrower range than the measurement region in order to compare at each measurement point. This method will be described later.

  When the final point angle is reached (step 245), the angle at which the average value of the signal intensity is minimized is obtained (step 246), and the orientation axis angle and the minimum transmitted light intensity at the measurement point are obtained. Details of this measurement operation will be described later. During this process, the relative position between the measurement optical system and the stage is changed to move to another measurement position (step 247). Therefore, the above measurement operation is repeated, and the desired measurement position set in advance is automatically measured. When measurement at all measurement points is completed (step 248), the measurement optical system is returned to the initial position (step 249), the stage 21 is moved forward (step 250), and the suction of the liquid crystal panel is released (step 249). 251). Thereafter, the measurement sample (liquid crystal panel) is replaced (step 252).

  Next, a method for detecting the mechanical posture of the liquid crystal panel with respect to the stage will be described. As described in the first embodiment, the end of the measurement sample may be detected by a camera, and this may be used as a reference. However, in the case of a liquid crystal panel, since there is an alignment mark for joining two substrates, a method for detecting the mechanical posture of the measurement sample (liquid crystal panel) using the alignment mark with respect to the stage will be described.

FIG. 22 is a schematic diagram of an image in the vicinity of the alignment mark photographed by the edge recognition camera in the orientation axis measurement. 22A shows the first alignment mark (part a), FIG. 22B shows the second alignment mark (part b), and FIG. 22C shows the vicinity of the third alignment mark (part c). Show. With respect to the liquid crystal panel on which the edge recognition camera is mounted on the stage, images near the positions of the alignment marks 65 in the a part, the b part, and the c part are captured. In FIG. 22, reference numeral 66 denotes an x-axis passing through the center of gravity, and reference numeral 67 denotes a y-axis passing through the center of gravity. Here, x and y in the images of the a part, the b part, and the c part are distinguished from each other by a, b, and c.

The shape of the alignment mark 65 is recognized from each image, and the barycentric coordinates (Δx _i , Δy _i ) are obtained. If the origin coordinates of each image with respect to the stage are (x _i , y _i ), the coordinates of the mark are (x _i + Δx _i , y _i + Δy _i ), and these position coordinates are obtained from two or more mark images. Perform linear approximation to recognize the orientation of the liquid crystal panel relative to the stage. Data on the orientation of the liquid crystal panel is reflected in the alignment axis measurement result to be measured later. Note that i = a, b, and c.

Here, a method for cutting out the same pattern in the measurement region will be described. Since the amount of transmitted light varies depending on the wavelength and the aperture ratio, this operation is necessary when there is a pixel pattern in the measurement region. This function is unnecessary in the case of measuring only the orientation axis angle without comparing the amount of transmitted light between measurement points, or in the case of a liquid crystal panel using a substrate without a pattern.

FIG. 23 is a diagram illustrating an example of a captured image at the first measurement point. FIG. 24 is a diagram showing a transmitted light amount distribution on the center line AB in FIG. At the time of capturing an image at the first measurement point, an area 92 surrounded by an arbitrary figure in the measurement area is designated. After the next measurement point, the transmitted light intensity is calculated by recognizing the same pattern from the shape of the black matrix portion 94 of the pattern and the transmitted light distribution on the center line 93 (FIG. 24).

Next, an alignment axis angle measuring method used in this apparatus will be described. FIG. 25 is a diagram for explaining plots at the time of measuring the orientation axis when the orientation axis measuring apparatus of the present invention is used. 25 (a) and 25 (b) show plotted orientation axis measurement results, and FIG. 25 (c) shows a measurement optical system. In the measurement optical system shown in FIG. 25 (c), since the polarizer 7 and the analyzer 8 are accompanied by a synchronous rotation mechanism 40, the light source unit can be obtained by rotating the polarization axis while holding two crossed Nicols. The polarization angle of the light irradiated from 30 to the liquid crystal panel 120 changes. If the polarizer 7 and the analyzer 8 are rotated with respect to the liquid crystal panel 120 while detecting the transmitted light by the camera 9, and the signal intensity of the transmitted light detection with respect to the angle is graphed, the result of FIG. 25A is obtained.

In this way, using the phenomenon that the signal intensity changes depending on the angle, first, while detecting the transmitted light, for example, the polarizer 7 and the analyzer 8 are rotated at a rough interval in an angle range of 120 ° to obtain a sine curve. A rough angle θ ₁ 77 that minimizes the amount of transmitted light is obtained by fitting. If a certain degree of orientation axis angle can be determined in advance, the above operation is not necessary. Thereafter, the transmitted light is detected while rotating the polarizer 7 and the analyzer 8 at a fine angle interval before and after the amount of transmitted light is minimized. FIG. 25 (b) shows a plot of signal intensity versus angle for the measurement result. A minimum value is obtained by fitting a curve such as a quadratic curve to the plot of FIG. The angle θ ₂ 78 that minimizes the amount of transmitted light is an angle at which the polarization axis of the polarizer 7 or the analyzer 8 coincides with the orientation axis of the liquid crystal panel 120, and the polarization axis angle of the polarizer 7 and the rough rubbing direction are known. Therefore, the orientation axis angle θ ₂ of the liquid crystal panel 120 that is a measurement object can be obtained.

FIG. 26 is a diagram illustrating an example of the operation image displayed on the image display unit provided in the control device of the transmitted light intensity angle dependency measuring apparatus according to the third embodiment of the present invention. An image 81 and a measurement graph 87 of a measurement area during measurement are shown, and the measurer can always monitor the measurement status. On the image 81, an area 82 for calculating the transmitted light intensity is shown. The display 88 shows the measurement results at the measurement points that have been measured so far for the in-plane orientation axis of the liquid crystal panel currently being measured. The angle of the arrow in the display 88 is a deviation angle from the reference axis. The display 89 shows the maximum value, minimum value, average value, and in-plane variation of the actual measurement value of the axial angle measurement result, and further, it is displayed in red when it exceeds a preset management value. It has become. The display 90 shows the minimum transmitted light intensity at each measurement point using contour lines, and corresponds to the in-plane luminance distribution (the intensity of the orientation regulating force can be predicted from this luminance distribution). In addition, the history display 91 can be used to view information on the liquid crystal panels measured so far, and the liquid crystal panels are automatically ranked according to the preset performance based on the respective measurement results. Results are also shown.

For example, in the case of a liquid crystal panel in which liquid crystal is sandwiched between two substrates having alignment regulating force, such as an IPS liquid crystal panel, the alignment regulating force direction of the two substrates is shifted and the liquid crystal alignment is twisted. The center angle of the angle formed by the alignment regulating force directions of the two opposing substrates can be obtained by the liquid crystal alignment axis angle measurement method of the third embodiment. However, only by measuring the liquid crystal alignment axis angle, information on the alignment regulating force direction of the substrate alone cannot be obtained, and the twist of the liquid crystal cannot be measured.

FIG. 41 is a diagram illustrating a first example of the alignment regulating force direction and alignment axis of the liquid crystal panel. For example, as shown in FIGS. 41 (a) and 41 (b), a first substrate 125 and a second substrate 127 having an orientation regulating force in the directions of arrows 126 and 128, respectively, are produced. Arrows 126 and 128 are angled by θ01 and θ02, respectively, from the center line of the substrate. When liquid crystal is sandwiched between these two substrates and combined in an anti-parallel manner, a liquid crystal panel 151 as shown in FIG. 41C is manufactured. The orientation axis angle of the panel 151 is the central angle θ03 formed by the orientation regulating force directions of the two substrates, that is, the angle obtained by adding θ01 and θ02 and dividing by two. On the other hand, as shown in FIGS. 42A and 42B to be described later, a substrate 125 and a substrate 127 having an orientation regulating force in the directions of the arrow 126 and the arrow 128 are produced.

FIG. 42 is a diagram illustrating a second example of the alignment regulating force direction and the alignment axis of the liquid crystal panel. For example, as shown in FIGS. 42A and 42B, the arrow 126B and the arrow 128B have an angle of θ03 and −θ03, respectively, from the center line of the substrate. When the substrate 125B and the substrate 127B are overlapped in an anti-parallel manner, as shown in FIG. 42 (c), the orientation regulating force angles of the opposing substrates coincide with each other, and a liquid crystal panel 152 having an angle θ03 from the center line is obtained. .

When the liquid crystal alignment axis angle of the liquid crystal panel 152 and the liquid crystal panel 151 is measured, a value of θ03 is obtained for both liquid crystal panels. However, the liquid crystal panel 151 actually has a twist angle, and when the polarizing plates are bonded to the top and bottom of the liquid crystal panel so that the transmitted light amount is minimized by crossed Nicols, the liquid crystal panel 152 is compared with the liquid crystal panel 151. The transmittance becomes lower. Thus, even if the liquid crystal alignment axis angle is the same, the performance of the liquid crystal panel may differ due to the presence of the twist angle. Here, a method of measuring the twist angle of the liquid crystal panel and obtaining the orientation regulating force direction of the single substrate having the orientation regulating force will be described in detail.

The transmitted light intensity angle dependency measuring apparatus according to the fourth embodiment is the same as the third embodiment in both the apparatus configuration and the configuration of the measurement optical system. However, since the twisting method changes depending on the wavelength of light, more accurate twist angle measurement can be performed by determining the wavelength distribution of the light source of the measurement optical system using a single color or a filter.

A measurement procedure using the apparatus of the present invention is also illustrated in FIG. The contents of angle calibration at the start of business (step 202 in FIG. 4) and measurement (step 203 in FIG. 4) are different from the polarization axis measurement of the polarizing film described in the first embodiment. Next, the angle configuration and measurement at the start of the operation of the apparatus according to Example 4 will be described.

As in the third embodiment, the angle calibration of the polarizer at the start of work is performed in steps 1001 to 1008 shown in FIG. 20, the angle of the polarizer is adjusted, and the polarizer and the analyzer are accurately crossed Nicols (polarization axis). Installed at right angles. Three procedures for measuring the twist angle are described below. The liquid crystal alignment axis angle measurement of the liquid crystal panel (step 268 in FIG. 43) is performed according to the procedure shown in FIG. 21 described in the third embodiment.

FIG. 43 is a diagram for explaining a first example of a torsion angle measurement procedure. In FIG. 43, the polarizer and the analyzer are set to crossed Nicols (step 269), the liquid crystal panel as the measurement object is placed on the stage, and the polarizer and the analyzer are rotated while being kept in the crossed Nicols, and the transmitted light amount (Step 270). The angle between the polarizer and the analyzer at that time is set to 0 °. The polarizer and analyzer are rotated to the measurement start angle (step 271), and the crossed nicols are solved (step 272).

The amount of transmitted light is measured with the analyzer fixed (step 273), the polarizer is rotated in increments of minute angles (step 275), and the amount of transmitted light at each angle is measured (step 273). When the polarizer reaches the measurement end angle (step 274), the polarizer is returned again to the measurement start angle (step 276). After rotating the analyzer by a minute angle (step 278), the analyzer is fixed, the polarizer is rotated by a minute angle, and the amount of transmitted light at each angle is measured. This operation is repeated until the analyzer angle reaches the measurement end point angle (step 277).

The transmitted light amount is drawn with contour lines on a graph with the analyzer angle on the vertical axis and the polarizer angle on the horizontal axis, and the angle between the polarizer and the analyzer that minimizes the transmitted light amount is obtained (step 279). The angle formed by the polarizer and the analyzer at that time is the twist angle of the light transmitted through the liquid crystal panel. FIG. 46 shows an example of the measurement result.

Since the amount of transmitted light has a minimum value at a polarizer angle of −1.25 ° and an analyzer angle of 1.25 °, the twist angle of light is 2.5 °. The above operation can obtain the same result even if the operations of the polarizer and the analyzer are reversed. Further, the measurement start angle and the measurement end angle are set in a range including an angle at which the transmitted light amount is minimum, and the step size is determined according to the required measurement accuracy.

FIG. 44 is a diagram for explaining a second example of the torsion angle measurement procedure. 44, the liquid crystal alignment axis angle measurement of the liquid crystal panel (step 268 in FIG. 44) is performed according to the procedure shown in FIG. 21 described in the third embodiment. The polarizer and analyzer are set to crossed Nicols (step 269), the liquid crystal panel as the measurement object is placed on the stage, and the polarizer and the analyzer are rotated while being kept in crossed Nicols, so that the amount of transmitted light is minimized. The angle (orientation axis angle) is adjusted (step 270). The angle between the polarizer and the analyzer at that time is set to 0 °.

The analyzer is fixed (step 280), the crossed nicols are solved (step 272), and the polarizer is rotated in small angular increments (step 275). While measuring the transmitted light amount at each angle (step 273), the angle at which the transmitted light amount is minimized is searched. When the angle reaches a minimum (step 274), this time, the angle of the polarizer is fixed (step 281), the analyzer is rotated by a small angle (step 282 in FIG. 44), and the amount of transmitted light at each angle is measured. However (step 283 in FIG. 44), the angle at which the amount of transmitted light is minimized is searched (step 284). The analyzer is fixed at an angle at which the amount of transmitted light is minimized (step 285), and the polarizer is rotated again. This operation is repeated to obtain the angle at which the transmitted light amount converges (step 287). The angle formed by the polarizer and the analyzer at that time is the twist angle of the light transmitted through the liquid crystal panel. The above operation can obtain the same result even if the operations of the polarizer and the analyzer are reversed. The step size is determined by the required measurement accuracy.

FIG. 45 is a diagram for explaining a third example of the torsion angle measurement procedure. 45, the liquid crystal alignment axis angle measurement of the liquid crystal panel (step 268 in FIG. 45) is performed according to the procedure shown in FIG. 21 described in the third embodiment. The polarizer and analyzer are set to crossed Nicols (step 269), the liquid crystal panel as the measurement object is placed on the stage, and the polarizer and the analyzer are rotated while being kept in crossed Nicols, so that the amount of transmitted light is minimized. The angle (orientation axis angle) is adjusted (step 270). The angle between the polarizer and the analyzer at that time is set to 0 °.

Cross Nicol is solved (step 272), the polarizer and the analyzer are slightly rotated in the opposite directions by the same angle (steps 293 and 294), the transmitted light amount is measured (step 291), and the angle at which the transmitted light amount is minimized is obtained. . The angle formed by the polarizer and the analyzer at that time is the twist angle of the light transmitted through the liquid crystal panel. If the determination end point angle is reached (step 292), the measurement is terminated (step 286).

In the first to third twist angle measurement methods, when Δnd is sufficiently large with respect to the measurement wavelength, the deviation angle from the crossed Nicols of the polarizer and the analyzer, that is, the twist angle of the light is used as it is. However, if Δnd is not sufficiently large with respect to the measurement wavelength, the Morgan condition is not satisfied, so there is a difference between the misalignment angle between the polarizer and the analyzer from the crossed Nicols and the angle at which the actual liquid crystal is twisted. . This difference may be determined by applying a certain coefficient, and this coefficient can be obtained from simulation based on Δnd and the measurement wavelength.

Since the light twisting method varies depending on the wavelength, it is necessary to separate the pixel pattern in the measurement region such as RGB. A method of cutting out the same pattern in the measurement region may be performed in the same manner as in FIG.

A method for managing the rubbing angle as the fifth embodiment of the present invention will be described with reference to FIGS. FIG. 27 is a diagram for explaining a manufacturing process for a liquid crystal panel according to Embodiment 5 of the present invention. In Example 5, first, the management number of the polarizing plate used for manufacturing the liquid crystal panel is recorded (step 324). Next, a polarization axis measurement is performed (step 325). The polarization axis measurement step 325 described here is in accordance with Example 1 of the present invention. Next, the polarizing plate management number and the polarization axis measurement result are stored together (step 326). Next, a liquid crystal panel production plan is formulated (step 327). Next, a TFT substrate and a CF substrate are manufactured (step 328). Next, an allocation plan for the TFT substrate, the CF substrate, and the polarizing plate is formulated (step 329). Next, a rubbing angle management value for the TFT substrate and the CF substrate is formulated (step 330). Next, the rubbing roller angle between the TFT substrate and the CF substrate is determined (step 331). Next, a liquid crystal panel is manufactured (step 332), and a polarizing plate is attached to the liquid crystal panel (step 333), thereby completing the liquid crystal panel.

FIG. 28 is a diagram for explaining in detail the content of step 331 (determining the rubbing roller angle between the TFT substrate and the CF substrate) in FIG. Therefore, after step 330 in FIG. 27, a series of steps in FIG. 28 is executed, and the process proceeds to step 332 in FIG. A series of steps will be described with reference to FIG. First, a rubbing process is performed on the TFT substrate and the CF substrate constituting the liquid crystal panel (step 301 and step 304). Next, after applying a sealing material (step 302) for bonding the CF substrate to the TFT substrate, liquid crystal is dropped (step 303). In this liquid crystal dropping (step 303), a volume of liquid crystal having a predetermined gap is dropped when the TFT substrate and the CF substrate are bonded together. Note that liquid crystal injection may be performed by vacuum sealing or the like after the TFT substrate and the CF substrate are overlaid, because the liquid crystal may be sandwiched between the two substrates, instead of dropping the liquid crystal.

Next, alignment (step 305) for adjusting the relative position between the TFT substrate and the CF substrate is performed and superposed so as to form a predetermined gap (step 306). Since the liquid crystal panel is completed when the superposition (step 306) is completed, the alignment axis measurement (step 307) is performed next. The orientation axis measurement uses the orientation axis measurement apparatus described in Example 3, and details of the procedure will be described later.

Next, a branch determination (step 308) is performed as to whether or not the orientation axis measurement result is within the management value. If the result of this branch determination indicates that the alignment axis measurement result is within the control value, the process transitions to rubbing roller angle determination (step 311) for the TFT substrate and the CF substrate at arrow 359. If it is determined in step 308 that the orientation axis measurement result does not fall within the management value, the process transitions to the rubbing process (step 301 and step 302) at arrow 355 or arrow 357.

If it is determined in the branching determination (step 308) that the orientation axis measurement result is not within the control value, the angle adjustment of the TFT substrate rubbing roller (step 309) or the CF substrate rubbing roller By adjusting the angle (step 310), the feedback indicated by the arrow 356 or the arrow 358 is applied to the rubbing process (step 301 or step 304). After this feedback, a series of processes from the rubbing step (step 301) to the alignment axis measurement step (step 307) are repeatedly executed until the result of the alignment axis measurement (step 308) converges within the control value. When the alignment axis measurement result converges within the control value, the rubbing roller angles for the TFT substrate and the CF substrate are determined (step 311). Next, a rubbing roller cutting amount setting process (step 312) is executed to determine rubbing conditions for the TFT substrate and the CF substrate (step 313). When step 313 in FIG. 28 is completed, the process proceeds to step 332 in FIG.

  FIG. 29 is an explanatory diagram of a TFT substrate and a CF substrate, FIG. 29 (a) is an enlarged plan view of a part of the TFT substrate used in the description of FIG. 28, and FIG. 29 (b) is used for the description of FIG. It is the top view which expanded a part of CF board which had been. The TFT substrate includes a gate wiring 132, a drain wiring 133, a pixel electrode (ITO) 134, a source electrode 135, and an a-Si semiconductor layer 136. Although not shown in FIG. 29A, an insulating film layer is formed to prevent a short circuit between the wiring layers and the electrode layers. An alignment film (not shown), which is an organic material, is applied to the TFT substrate after these wirings are formed. The alignment film is subjected to a rubbing process in step 301 of FIG. Here, the angle of the alignment regulating force of the TFT substrate is θTFT. This angle is illustrated as an angle with respect to a line (dashed line) parallel to the extending direction (Y direction) of the drain wiring 133.

The CF substrate shown in FIG. 29B includes a black matrix 142 and color resists 143, 144, and 145. The black matrix 142 is formed to have a size that covers the lattice formed by the gate wiring 132 and the drain wiring 133 of the TFT substrate shown in FIG. The color resists 143, 144, and 145 are color filters. Each of the color resists 143, 144, and 145 is, for example, three primary colors of red (R), green (G), and blue (B). Performs the function to reproduce. In FIG. 29B, the three primary colors are used, but three or more colors may be used. After the black matrix 142 and the color resists 143, 144 and 145 are formed on the CF substrate, an alignment film (not shown) made of an organic material is applied. The alignment film is subjected to a rubbing process in step 304 of FIG. Here, the angle of the orientation regulating force of the CF substrate is θCF. This angle is also shown as an angle with respect to a line (dotted line) parallel to the Y direction of the black matrix 142.

FIG. 30 is a diagram for explaining a series of processes of the sealing material application step 302, the liquid crystal dropping step 303, the alignment step 305, and the overlaying step 306 shown in FIG. The TFT substrate 131 and the CF substrate 141 are in a stage where the rubbing processing step 301 and step 304 in FIG. 28 are completed. First, for each display panel area on the CF substrate 141 using the seal dispenser 167, the seal material 124 is applied around the display area. The application shape of the sealing material 124 is substantially the same as the shape of the liquid crystal panel. In FIG. 30, the sealing material 124 is drawn so that four liquid crystal panels can be formed from the CF substrate 141. After applying the sealing material 124, the liquid crystal 122 is dropped on the CF substrate 141 by the dispenser 169.

Next, the TFT substrate 131 and the CF substrate 141 are put into the vacuum chamber 168. In this vacuum chamber 168, the processing of the alignment step 305 and the superposition step 306 shown in FIG. Thereafter, by returning the pressure in the vacuum chamber 168 to atmospheric pressure, a liquid crystal panel in which the TFT substrate 131 and the CF substrate 141 are bonded together with a predetermined gap is completed.

FIG. 31 is an enlarged plan view of a part of the liquid crystal panel in which the overlapping step 306 in FIG. 28 is completed. The orientation regulating force 137 of the TFT substrate 131 and the orientation regulating force 146 of the CF substrate 141 shown in FIG. The alignment axis measurement shown in step 307 of FIG. 28 is to measure the alignment axis that appears as a liquid crystal panel. The alignment axes are the alignment regulating force 137 of the TFT substrate and the alignment regulating force 146 of the CF substrate shown in FIG. Expressed in

FIG. 32 is a diagram for explaining alignment axes that appear when the TFT substrate 131 and the CF substrate 141 are overlapped to complete the liquid crystal panel. 32 (a), 32 (b), and 32 (c), the alignment regulating force 137 of the TFT substrate of the liquid crystal panel, the alignment regulating force 146 of the CF substrate, and the alignment axis 121 as the liquid crystal panel expressed by these. It is shown. The alignment axis 121 of the liquid crystal panel is an intermediate angle between the alignment regulating force 137 of the TFT substrate and the alignment regulating force 146 of the CF substrate. That is, the alignment axis angle θPanel of the liquid crystal panel is given by the following first formula.
θPanel = (θTFT + θCF) / 2 (1)

FIG. 32A shows a case where the orientation regulating force 146 of the CF substrate 141 is at a larger angle than the orientation regulating force 137 of the TFT substrate 131. That is, as shown in the following second formula, θTFT <θCF (2)
This is the case.

FIG. 32B shows a case where the orientation regulating force 137 of the TFT substrate 131 is at a larger angle than the orientation regulating force 146 of the CF substrate 141. That is, as shown in the following equation 3, θCF <θTFT (3)
This is the case.

FIG. 32C shows a case where the alignment regulating force 137 of the TFT substrate 131 and the alignment regulating force 146 of the CF substrate 141 are the same angle. That is, as shown in the following fourth formula, θCF = θTFT (4)
This is the case.

Therefore, in the orientation axis measurement processing step 307 of FIG. 28, the orientation axis 121 shown in FIGS. 32A, 32B, and 32C is measured, and the angle of the orientation axis 121 is measured. Adjustment of the angle of the rubbing roller for the TFT substrate (step 309 in FIG. 28) and adjustment of the angle of the rubbing roller for the CF substrate (step 310 in FIG. 28) are performed by the same amount. Thereby, the adjusted orientation axis 121 can be set so that the angle formed with the Y direction of the XY coordinates becomes zero, as shown in FIGS. 32 (a), 32 (b), and 32 (c). Further, since the angle formed by the alignment regulating forces 146 and 137 can be obtained by the fourth embodiment method, the angle of the rubbing roller for the TFT substrate (step 309 in FIG. 28) and the angle of the rubbing roller for the CF substrate are adjusted. By repeating this adjustment (step 310 in FIG. 28), it is possible to set an ideal state where the angle between the adjusted orientation regulating forces 146 and 137 and the Y direction is zero.

FIG. 33 shows a series of processes for bringing the orientation regulating force angle θTFT of the TFT substrate close to zero. 33, steps 301, 302, 303, 321, and 322 are the same as steps 301, 302, 303, 305, and 306, which are a series of processes shown in FIG. In FIG. 28, the superposition (step 306 in FIG. 28) is performed using the TFT substrate and the CF substrate, but in FIG. 33, the superposition (step 322 in FIG. 33) is performed using two TFT substrates. Thereafter, by measuring the twist angle by the method described in Example 4 (step 323 in FIG. 33), the orientation regulating force direction of the TFT substrate can be determined, and the angle is fed back to the rubbing condition (step in FIG. 33). 355). This is repeated to determine the angle of the rubbing roller (step 314 in FIG. 33).

FIG. 34 is an explanatory diagram of an alignment axis that appears in the liquid crystal panel composed of the TFT substrate configured in the case of FIG. 33 and the two TFT substrates illustrated in FIG. 41, and FIG. FIG. 34 (b) is a diagram schematically showing the orientation axis. In FIG. 34 (a), the two TFT substrates 131 are partially cut out for easy understanding. Each TFT substrate 131 develops an alignment regulating force 137. In this state, an alignment axis as a liquid crystal panel appears between the alignment regulating forces 137 of the two TFT substrates.

FIG. 34 (b) schematically shows alignment axes that appear in a liquid crystal panel composed of the two TFT substrates shown in FIG. 34 (a). Since the alignment restriction force 137 of the TFT substrate is the same angle between the two TFT substrates, the alignment axis 121 of the liquid crystal panel constituted by the two TFT substrates coincides with the Y axis. However, the angle θTFT formed by the alignment regulating force 137 of the upper and lower TFT substrates can be obtained by measuring the twist angle using the method of Example 4.

FIG. 35 is a diagram for explaining a series of processes for bringing the orientation regulating force angle θCF of the CF substrate close to zero. 35, steps 304, 316, 317, 318, and 319 are the same as steps 301, 302, 303, 321, and 322, which are a series of processes shown in FIG. In FIG. 33, superposition (step 322 in FIG. 28) is performed using two TFT substrates, but in FIG. 35, superposition (step 319 in FIG. 28) is performed using two CF substrates.

FIG. 36 is an enlarged plan view showing a part of the CF substrate configured in the case of FIG. In FIG. 36, the two CF substrates 141 are partially cut out to facilitate understanding. Each CF substrate 141 expresses an alignment regulating force 146. In this state, an alignment axis as a liquid crystal panel appears between the alignment regulating forces 146 of the two CF substrates. Regarding the procedure for obtaining the angle θCF formed by the alignment regulating force 146 of the upper and lower CF substrates by superimposing the two CF substrates 141, the liquid crystal panel alignment regulating force 137 and the angle θTFT constituted by the two TFT substrates described above. It is the same as the method for obtaining. That is, by the method described with reference to FIGS. 33, 34, 35, and 36, the rubbing roller so that the alignment regulating force 137 of the TFT substrate and the alignment regulating force 146 of the CF substrate completely coincide with the Y axis of the XY coordinates. Can be set. In this embodiment, the rubbing method is used as a method for giving alignment regulating force, but a non-contact alignment method such as photo-alignment can also be used as the liquid crystal panel manufacturing method shown in this embodiment.

As a sixth embodiment of the present invention, a polarization axis measuring apparatus according to the first embodiment will be described with reference to FIGS. 37 and 38. FIG. 37 is an explanatory diagram of a polarization axis measuring apparatus according to a sixth embodiment of the present invention. FIG. 37 (a) is a plan view, FIG. 37 (b) is a side view, and FIG. 37 (c) is a light intensity recognition unit 50. It is a figure explaining the internal structure of. FIG. 38 is an explanatory diagram of the light source unit in FIG. 37, FIG. 38 (a) is a diagram showing a cross section of the plane, and FIG. 38 (b) is a diagram showing a side view of the internal structure. In this embodiment, a light intensity recognition unit 50, a light intensity recognition unit moving mechanism 51, and a light intensity recognition unit moving mechanism support 52 are constructed on the surface plate 20. A stage 21 that holds the measurement sample 100 is constructed on the stage moving mechanism 22.

The stage moving mechanism 22 is constructed on the surface plate 20. The light intensity recognition unit 50 has a structure in which the end and the mark detection CCD camera 9 are held on the side surfaces. The stage 21 is provided with light transmitting portions 23 at a predetermined pitch so that the polarization axis of the measurement sample 100 can be measured at a predetermined pitch. Here, the light intensity recognition unit 50 can move in one direction, and the stage 21 can move in one direction orthogonal to the movement direction of the light intensity recognition unit. In this embodiment, the light intensity recognition unit 50 is movable in the X direction and the stage 21 is movable in the Y direction. However, the light intensity recognition unit 50 is movable in the Y direction and the mounting base 21 is movable in the X direction. A mechanism may be constructed as is.

In FIG. 37 (b), in the sixth embodiment, the light source unit 30 is held by a mechanism that can move in the X direction in the drawing, and maintains the relative position in the X direction with the light intensity recognition unit 50, in synchronization. Moving. Therefore, the light for measurement always derived from the light source unit 30 passes through the light transmission part 23 and enters the light intensity recognition unit 50 after passing through the measurement sample 100.

In FIG. 37 (c), the light intensity recognition unit 50 includes a CCD camera 9, a rotation analyzer unit 43, and a rotation analyzer unit driving mechanism 42. The analyzer 8 held inside the rotation analyzer unit 43 is rotated by the rotation analyzer unit driving mechanism 42 to measure the polarization axis.

In FIG. 38 (a), the light beam emitted from the lamp 1 is bent at 90 ° by the mirror 3 via the lens 2. Thereafter, after passing through the diaphragm 4, it passes through the filter 5, is bent in the Z direction (perpendicular to the paper surface) by the mirror 6, and enters the analyzer 7 held by the rotating polarizer unit 41. The rotating polarizer unit 41 can change the absorption axis angle of the polarizer 7 by the rotating polarizer unit driving mechanism 40.

In FIG. 38B, the filter 5 functions as a pass filter that transmits only an arbitrary wavelength with the light emitted from the light source 1 when measuring the polarization axis. Thereby, the polarization axis measurement at an arbitrary wavelength is realized.

Embodiment 7 of the polarization axis measuring apparatus according to the present invention will be described with reference to FIGS. 39 and 40. FIG. FIG. 39 is an explanatory view of a polarization axis measuring apparatus according to a seventh embodiment of the present invention. FIG. 39 (a) is a plan view and FIG. 39 (b) is a side view. FIG. 40 is an explanatory diagram of the internal structure of the light source unit 30 in the seventh embodiment of the polarization axis measuring apparatus according to the present invention. FIG. FIG. In this embodiment, the light intensity recognition unit 50, the light intensity recognition unit moving mechanism 51, and the light intensity recognition unit moving mechanism support 52 are constructed as an integral structure. On the surface plate 20, a stage 21 that holds the measurement sample 100 is constructed on a stage moving mechanism 22. Further, the light source unit 30 is configured as a structure integrated with the surface plate 20.

That is, in this embodiment, the polarization axis measuring apparatus is configured with the surface plate 20 as one unit and the light intensity unit moving mechanism support 52 as another unit. Therefore, even if the dimension of the measurement sample 100 is increased, the polarization axis measuring device can be disassembled and transported, so that it can be easily introduced into a newly established factory. In addition, since the light intensity recognition unit 50, the light intensity recognition unit moving mechanism 51, and the light intensity recognition unit moving mechanism support 52 can be transported without being disassembled, the accuracy represented by the straight travel is maintained. it can.

In addition, since the light source unit 30 can be transported without disassembling while the light source unit 30 is configured on the surface plate 20, the accuracy represented by the straightness can be maintained. When two units are started up in a new factory, the relative alignment between the light intensity recognition unit 50 and the light source unit 30 and the orthogonality between the straight direction of the light intensity recognition unit moving mechanism 31 and the straight direction of the stage 21 are managed. Just do it.

In FIG. 40, a light beam emitted from a single wavelength light source 11 (for example, a laser) has its optical path bent by 90 ° by a mirror 3 via a lens 2. Thereafter, after passing through the diaphragm 4, it passes through the filter 5, is bent in the Z direction (perpendicular to the paper surface) by the mirror 6, and enters the polarizer 7 held by the rotating polarizer unit 41. The rotating polarizer unit 41 can change the absorption axis angle of the polarizer 7 by a rotating polarizer unit driving mechanism 42. In this embodiment, since the single wavelength light source 11 is used, the light intensity recognition unit 50 is equipped with a light receiving element (not shown) having high sensitivity in the wavelength band of the light source.

In the sixth and seventh embodiments of the present invention described above, the apparatus configuration of the polarization axis measuring apparatus has been described. However, the measurement apparatus apparatus according to the second, third, and fourth embodiments of the present invention. It is good also as a structure.

The optical anisotropic axis measuring device of the present invention described above is conventionally provided by using a highly accurate measuring optical system by setting the measurement coordinates by recognizing the edge surface of the measurement object by the image recognition means. Optical anisotropic axis measurement can be realized with higher accuracy than existing measuring devices. In addition, since the optical anisotropic axis measuring apparatus according to the present invention is equipped with a polarizing plate for calibration, the apparatus is always calibrated at the start of measurement, and it is automatically checked whether there is any abnormality by comparing with the previous history. Diagnose. In addition, since the measurement optical system moves relative to the object to be measured, the footprint is smaller than the movement of the stage, resulting in huge things such as the width of the optically anisotropic film and the size of the mother glass substrate of the liquid crystal panel. Can also respond. That is, according to the present invention, optical anisotropic axis measurement can be performed with high accuracy for a large measurement object, and the quality and performance of an optically anisotropic film, which is an important member for a liquid crystal display, can be promoted.

In addition, since the optical anisotropic axis measuring apparatus of the present invention can also measure the orientation axis and twist angle of the liquid crystal panel, a liquid crystal panel for check is prepared before mass production during the production of the liquid crystal panel. When the torsion angle is measured and the value is outside the control value, the orientation imparting conditions are fed back, and the mass production can be performed after setting the value to be within the control value. In the prior art, since the alignment axis is not managed in advance, the alignment axis varies from start to finish. According to the present invention, it is possible to stably mass-produce liquid crystal panels having alignment axes with accuracy within the control value. become. In addition, the orientation axis angle of the liquid crystal panel is determined from the measurement result of the optical anisotropic axis angle of each optically anisotropic film measured in advance, and the optical axis design of the panel is designed according to the optical axis angle of the optically anisotropic film. Yes.

Furthermore, by selecting an optimal combination from each optically anisotropic material and superimposing them at a desired angle, a product that maximizes the performance of each material can be manufactured. In addition, since the optical performance after superposition can be predicted and ranked, the inspection items after superposition can be reduced.

From the above, the optical performance of both the optically anisotropic film and the liquid crystal panel constituting the liquid crystal display is improved, and the overlay accuracy with respect to the optical anisotropic axis is also improved, which can contribute to the improvement of the image quality of the liquid crystal display.

It is explanatory drawing of Example 1 of the polarization axis measuring apparatus by this invention. It is a top view of the polarization axis measuring device explaining Example 1 of the present invention. It is a figure which shows the measurement optical system in the polarization axis measuring apparatus of Example 1 of this invention. It is a figure explaining the measurement procedure using the polarization axis measuring apparatus in Example 1 of this invention. It is a figure explaining the detailed procedure of the angle calibration step of the polarizer at the time of the start of FIG. It is a figure explaining the detailed procedure of the polarization axis measurement of the polarizing film in FIG. 5 using the optical system of FIG. 3 (a). It is a schematic diagram of the image image | photographed with the edge part recognition camera in the polarization axis measurement of Example 1 of this invention. It is explanatory drawing of the image and histogram which the light intensity detection means of the optical system shown in FIG. 3 acquired. It is explanatory drawing of the average signal strength at the time of the polarization axis measurement using the polarization axis measuring apparatus of this invention. It is a figure explaining an example of the image displayed on the image display means with which the control apparatus of the polarization axis measuring apparatus in Example 1 of this invention was equipped. It is a figure which shows the optical system in the compound-optical anisotropic-axis measuring apparatus of Example 2 of this invention. It is a figure which shows switching of the light intensity recognition unit in Example 2 of this invention. It is a figure explaining the procedure about the polarizer angle calibration at the time of the start of the compound-optical anisotropic-axis measuring apparatus of Example 2 of this invention. It is a figure which shows the 1st example of the normal measurement procedure of the compound-optical anisotropic-axis measuring apparatus of Example 2 by this invention. It is a figure which shows the 2nd example of the normal measurement procedure of the compound-optical anisotropic-axis measuring apparatus of Example 2 by this invention. It is a figure which shows an example of the image displayed on the image display means with which the control apparatus of the compound-optical anisotropic-axis measuring apparatus concerning Example 2 of this invention was equipped. It is a schematic diagram explaining an example of a liquid crystal display. It is a figure explaining the alignment film preparation method of a liquid crystal panel. It is a figure explaining expression of an orientation axis by superposition of a glass substrate. It is a figure explaining the procedure of the polarizer angle calibration at the time of the start in Example 3 of this invention. It is a figure explaining the detailed procedure about the orientation axis measurement of the liquid crystal panel in Example 3 of this invention. It is a schematic diagram of the image of the alignment mark vicinity image | photographed with the mark recognition camera in orientation axis measurement. It is a figure explaining the example of the captured image in the first measurement point. It is a figure which shows the transmitted light amount distribution on centerline AB of FIG. It is a figure explaining the plot at the time of the orientation axis | shaft measurement when the orientation axis | shaft measuring apparatus of this invention is used. It is a figure which shows an example of the image represented on the image display means with which the control apparatus of the orientation axis | shaft measuring apparatus concerning Example 3 of this invention was equipped. It is a figure which shows the flow of the manufacturing process of a liquid crystal panel. It is the figure which showed the content of step 331 of FIG. 27 in detail. It is the figure which expanded a part of TFT substrate and CF substrate. It is a figure which shows a series of processes of superimposition from sealing material application | coating. FIG. 4 is an enlarged view of a part of a liquid crystal panel that has been superposed. It is a figure which shows an example of the orientation axis which expresses by superimposition. It is a figure which shows the calibration procedure of the orientation control force direction of a TFT substrate. It is explanatory drawing of the orientation axis | shaft and twist angle which are expressed with the liquid crystal panel which piled up TFT substrates. It is a figure which shows the calibration procedure of the orientation control force direction of CF board | substrate. It is an enlarged view of a part of a liquid crystal panel in which CF substrates are overlapped. It is explanatory drawing of the polarization axis measuring apparatus concerning Example 6 by this invention. It is explanatory drawing of the internal structure of the light source unit 30 shown in FIG. It is explanatory drawing of Example 7 of the polarization axis measuring apparatus by this invention. It is explanatory drawing of the internal structure of the light source unit 30 shown in FIG. It is a figure which shows the 1st example of the alignment control force direction and alignment axis of a liquid crystal panel. It is a figure which shows the 2nd example of the alignment control force direction and alignment axis of a liquid crystal panel. It is a figure explaining the 1st example of the twist angle measurement procedure of this invention. It is a figure explaining the 2nd example of the torsion angle measurement procedure of this invention. It is a figure explaining the 3rd example of the twist angle measurement procedure of this invention. It is a figure which shows one measurement result in the twist angle measurement procedure of a 1st example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source (general, lamp), 2 lens, 3,6 mirror, 4 stop, 5 wavelength filter, 7 Polarizer, 8 Analyzer, 9,19 Camera (CCD camera), 10 Lens (zoom lens), 11 Single Wavelength light source, 12 1/4 wavelength plate, 20 surface plate, 21 stage (measurement sample mounting table), 22 stage moving mechanism, 23 light transmission part, 24 alignment pin, 25 edge recognition camera, 26 standard polarizer, 30 Light source unit, 31 Light source unit moving mechanism, 40 Synchronous rotation mechanism, 41 Rotating polarizer unit, 42 Rotating drive unit, 43 Rotating analyzer unit, 50 Light intensity recognition unit, 51 Light intensity unit moving mechanism, 52 Light intensity recognition unit movement Mechanism support, 100 measurement sample, 101 polarizing film, 102 polarization axis, 111 composite film, 112 phase Difference plate, 113 delay axis, 120 liquid crystal panel, 121 orientation axis, 122 liquid crystal, 123 orientation film, 124 seal, 125 first glass substrate, 126 orientation regulating force direction of first glass substrate, 127 second glass substrate , 128 Alignment regulating force direction of the second glass substrate, 129 inlet seal, 131 TFT substrate, 132 gate wiring, 133 drain wiring, 134 pixel electrode (ITO), 135 source electrode, 136 semiconductor layer, 137 TFT substrate orientation Regulating force direction, 141 CF substrate, 142 black matrix, 143, 144, 145 color resist, 146 CF substrate orientation regulating force direction, 150 twist angle, 151,152 liquid crystal panel, 160 doctor blade, 161 solution supply roll, 162 plate Cylinder, 163 printing plate, 164 rubbing low 165, substrate feeding direction, 166 rubbing direction, 167 seal dispenser, 168 vacuum chamber, 169 liquid crystal dispenser, 171 backlight.

Claims (15)

A mounting base for the measurement object having optical anisotropy, and an edge surface of the measurement object mounted on the mounting base or an alignment mark provided on the measurement object with respect to the mechanical coordinates of the mounting base An end for recognizing the posture of the measurement object and mark recognition means, a light source unit, a measurement optical system that forms an optical path between the incident side and the emission side with respect to the measurement object, and light intensity recognition means ,
The mounting table that is installed in the optical path of the measurement optical system and mounts the measurement object includes a light transmission unit that transmits light from the light source at an arbitrary position of the measurement object,
The light from the light source passes through the light transmitting means provided on the mounting base from the incident side of the measurement optical system, the measurement object mounted on the mounting base, and the measurement optical system on the output side. It is arranged to be incident on the light intensity recognition means,
An optically anisotropic axis characterized in that a polarizer capable of controlling the attitude, an analyzer capable of controlling the attitude, and a phase plate capable of controlling the attitude are installed in an optical path from the light source to the light intensity recognition means. measuring device. After the measurement object is mounted on the mounting base of the measurement object, a plurality of alignment marks provided on the edge surface of the measurement object or the measurement object are recognized by the end part and the mark recognition means,
The optical anisotropic axis of the measurement object is measured with respect to coordinates according to the posture of the measurement object with respect to the mechanical coordinates of the mounting base based on the recognition. Optical anisotropic axis measuring device. The light source unit, the incident-side measuring optical system, the emitting-side measuring optical system, and the light intensity recognition means constitute one optical system,
3. The optical anisotropic axis measurement according to claim 1, wherein the one optical system moves in the plane of the measurement object and can measure an optical anisotropic axis at an arbitrary position. apparatus.   4. The optical anisotropic axis angle of the measurement object is determined based on the light intensity obtained by rotating the at least one polarizer and the light intensity recognition means. The optical anisotropic axis measuring device according to any one of the above.   5. The filter according to claim 1, further comprising a filter between the light source and the measurement object, wherein light having an arbitrary wavelength and an arbitrary amount of light passes through the light intensity recognition unit. Optical anisotropic axis measuring device.   Provided with a material having optical anisotropy for calibration with a clear absolute angle of the optical anisotropic axis at a position measurable by the measurement optical system, and has a function of performing calibration work at startup or at arbitrary time intervals The optical anisotropic axis measuring apparatus according to claim 1, wherein   7. The optical system according to claim 1, further comprising an interchangeable lens between the object to be measured and the light intensity recognizing means, wherein the width of the measurement region can be arbitrarily set. An anisotropic axis measuring device.   8. The optical anisotropic axis measuring apparatus according to claim 1, wherein the light source unit includes a light source having a plurality of wavelength peaks and a relay optical system.   The optical anisotropic axis measuring apparatus according to claim 1, wherein the light source unit includes a light source having a single wavelength peak and a relay optical system.   The retardation plate has a known retardation axis angle and retardation, and each optical anisotropic axis angle of the polarizer, the retardation plate and the analyzer can be controlled independently, and polarization dichroism The optical anisotropic axis measuring device according to claim 1, wherein the optical anisotropic axis of each of the composite optical sheets obtained by superimposing the substance having retardation and the substance having retardation is measured.   Rotating the polarizer and the analyzer with respect to the composite optical sheet, and determining a polarization axis angle and a delay axis angle of the composite optical sheet based on a light intensity obtained by a light intensity recognition unit. The optical anisotropic axis measuring device according to claim 10. The optically anisotropic axis according to any one of claims 1 to 11 , wherein at least the analyzer and the retardation plate of the polarizer, the retardation plate, and the analyzer are detachable. measuring device. The measurement optical system includes a polarizer capable of controlling the posture and an analyzer capable of controlling the posture,
10. The optical anisotropic axis measuring device according to claim 1, wherein the orientation axis is measured by controlling the polarization axis angles of the polarizer and the analyzer in synchronization with each other.   The measurement optical system includes a polarizer capable of controlling the attitude and an analyzer capable of controlling the attitude, and the polarization axis angles of the polarizer and the analyzer are rotated in synchronization with each other, and obtained by the light intensity recognition unit. 10. The method according to claim 1, wherein a polarization axis angle of a measurement object having polarization dichroism or a light distribution axis angle of a measurement object having refractive index anisotropy is determined based on light intensity. An optical anisotropic axis measuring device described in 1. The measurement optical system includes a polarizer capable of controlling the posture and an analyzer capable of controlling the posture,
10. The optical anisotropic axis measuring apparatus according to claim 1, wherein the twist angle of the liquid crystal panel is measured by making it possible to independently control the polarization axis angles of the polarizer and the analyzer.

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