JP6584947B2 - Pretilt angle measuring device and pretilt angle measuring method - Google Patents

Description

  The present invention relates to a pretilt angle measuring apparatus and a pretilt angle measuring method, and more particularly to measuring a pretilt angle of liquid crystal molecules contained in a liquid crystal substrate.

  Patent Document 1 below discloses a technique for detecting transmitted light intensity of light transmitted through a liquid crystal cell at a plurality of incident angles and detecting a pretilt angle of the liquid crystal cell based on an apparent retardation corresponding to the plurality of incident angles. It is disclosed.

JP 2001-356072 A

  Since the above technique uses a transmission optical system, it is necessary to irradiate or receive light below the liquid crystal substrate. Therefore, it is first considered that the base that supports the entire lower surface of the liquid crystal substrate is made of a transparent member such as glass. However, in this case, since light is refracted inside the transparent member, there is a possibility that an error occurs due to a deviation in the optical axis. Further, when distortion due to stress occurs in the transparent member, the polarization state of light is disturbed, and an error may occur.

  Therefore, in order to eliminate the influence of such a transparent member, it is also considered to place a liquid crystal substrate on a plurality of bars arranged at intervals, and to irradiate or receive light through gaps between the bars. However, since the liquid crystal substrate bends due to its own weight in the gap between the bars, the incident angle of light used for the calculation may deviate from the actual incident angle, which may cause an error. Such problems have become more prominent in recent years as liquid crystal substrates have become larger and thinner.

  The present invention has been made in view of the above problems, and an object thereof is to provide a pretilt angle measuring device and a pretilt angle measuring method capable of suppressing errors.

  In order to solve the above-described problem, a pretilt angle measuring apparatus according to the present invention includes a first light projecting unit that irradiates a measurement position of a liquid crystal substrate with polarized measurement light, and receives the transmitted light of the measurement light and transmits the transmitted light. A first light receiving unit that acquires a polarization state of light, a second light projecting unit that irradiates the measurement position of the liquid crystal substrate with tilt detection light, and a reflected light of the tilt detection light; A second light-receiving unit that obtains a light-receiving position of the reflected light; an inclination-angle calculating unit that calculates an inclination angle of the measurement position of the liquid crystal substrate based on the light-receiving position of the reflected light; and irradiation of the measurement light A pretilt angle calculator that calculates a pretilt angle of liquid crystal molecules included in the liquid crystal substrate based on the angle, the tilt angle of the measurement position of the liquid crystal substrate, and the polarization state of the transmitted light.

  Further, the pretilt angle measuring method of the present invention irradiates the measurement position of the liquid crystal substrate with the polarized measurement light, receives the transmitted light of the measurement light, acquires the polarization state of the transmitted light, and detects the tilt detection light. Is irradiated to the measurement position of the liquid crystal substrate, the reflected light of the tilt detection light is received, the light receiving position of the reflected light is obtained, and the light receiving position of the reflected light is used to obtain the light receiving position of the reflected light. The tilt angle of the measurement position is calculated, and the pretilt of the liquid crystal molecules contained in the liquid crystal substrate is calculated based on the irradiation angle of the measurement light, the tilt angle of the measurement position of the liquid crystal substrate, and the polarization state of the transmitted light. Calculate the corner.

  In addition, a mirror may be further provided that reflects the tilt detection light from the second light projecting unit to the liquid crystal substrate and reflects the reflected light from the liquid crystal substrate to the second light receiving unit.

  Further, the second light receiving unit receives the reflected light at a plurality of positions having different distances from the liquid crystal substrate, and the tilt angle calculating unit receives the reflected light at the respective positions. Based on this, an inclination angle of the measurement position of the liquid crystal substrate may be calculated.

  The second light receiving unit receives the reflected light at a plurality of positions having different angles with respect to the liquid crystal substrate, and the tilt angle calculating unit is based on a light receiving position of the reflected light received at each of the positions. Then, the inclination angle of the measurement position of the liquid crystal substrate may be calculated.

  The first light projecting unit and the first light receiving unit may be supported so as to be rotatable about a vertical line passing through the measurement position.

  Further, the second light projecting unit and the second light receiving unit irradiate the tilt detection light within a plane including the first light projecting unit, the first light receiving unit, and the measurement position. The first light projecting unit and the first light receiving unit together with the first light projecting unit and the first light receiving unit may be supported so as to be pivotable about a vertical line passing through the measurement position.

  A first surface including the first light projecting unit, the first light receiving unit, and the measurement position; and the second light projecting unit, the second light receiving unit, and the measurement position. An intersection angle acquisition unit that acquires an intersection angle with the second surface is further provided, and the inclination angle calculation unit is configured to determine an inclination angle of the measurement position of the liquid crystal substrate in the first surface based on the intersection angle. May be calculated.

  According to the present invention, since the pretilt angle is calculated using the tilt angle of the measurement position of the liquid crystal substrate, it is possible to suppress errors.

It is a schematic block diagram which shows the 1st example of the pretilt angle measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the optical path of the inclination measurement optical system of FIG. It is explanatory drawing for demonstrating the light-receiving surface of a 2nd light-receiving part. It is an operation | movement flowchart which shows the 1st example of the pretilt angle measuring method which concerns on embodiment of this invention. It is a schematic block diagram which shows the 2nd example of the pretilt angle measuring apparatus which concerns on embodiment of this invention. It is an operation | movement flowchart which shows the 2nd example of the pretilt angle measuring method which concerns on embodiment of this invention. It is a schematic block diagram which shows the 3rd example of the pretilt angle measuring apparatus which concerns on embodiment of this invention. It is an operation | movement flowchart which shows the 3rd example of the pretilt angle measuring method which concerns on embodiment of this invention. It is a schematic block diagram which shows the 4th example of the pretilt angle measuring apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the 5th example of the pretilt angle measuring apparatus which concerns on embodiment of this invention. It is a schematic block diagram which shows the state which rotated the transmission measurement optical system 90 degree | times from the state of FIG. It is explanatory drawing for demonstrating the angle | corner which a transmission measurement surface and an inclination measurement surface make.

  Embodiments of the present invention will be described with reference to the drawings.

[First example]
FIG. 1 is a schematic configuration diagram showing a first example of a pretilt angle measuring apparatus 1 according to an embodiment of the present invention. The pretilt angle measuring device 1 is a device that measures the pretilt angle of the liquid crystal molecules contained in the liquid crystal substrate LC to be measured. The pretilt angle is a tilt angle of liquid crystal molecules in the substrate thickness direction.

  The liquid crystal substrate LC to be measured is placed on a plurality of bars 8 arranged at intervals. The bar 8 may be provided with a plurality of ball bearings that contact the lower surface of the liquid crystal substrate LC. The liquid crystal substrate LC is a large substrate including a plurality of panel regions before the plurality of liquid crystal panels are cut out, for example. However, the present invention is not limited to this, and one cut out liquid crystal panel may be a measurement target. In the description and drawings of this specification, the direction in which the plurality of bars 8 are arranged in the horizontal plane is defined as the X direction, and the direction in which the plurality of bars 8 extend is defined as the Y direction. The vertical direction is the Z direction.

  The pretilt angle measuring apparatus 1 includes a transmission measurement light projecting unit 2 and a transmission measurement light receiving unit 3 as a transmission measurement optical system. The transmission measurement light projecting unit 2 is an example of a first light projecting unit, and irradiates the measurement position M of the liquid crystal substrate LC with polarized measurement light. The transmission measurement light receiving unit 3 is an example of a first light receiving unit, and receives the transmitted light of the measurement light and acquires the polarization state of the transmitted light.

  The transmission measurement light projecting unit 2 converts the measurement light that has been made parallel by the lens 23 into a linearly polarized light, a light source 21 that generates the measurement light, a lens 23 that converts the measurement light supplied from the light source 21 through the fiber into parallel light, and the like. And a polarizer 25 for polarizing. As the light source 21, for example, a white light source having a flat output characteristic in a wide wavelength region is preferable. The polarizer 25 is, for example, with respect to a surface (hereinafter referred to as a transmission measurement surface) on which an optical path of measurement light emitted from the transmission measurement light projecting unit 2 and transmitted light received by the transmission measurement light receiving unit 3 is formed. 45 degree linearly polarized light is generated.

  The transmission measurement light receiving unit 3 includes a rotation analyzer 31, a lens 33 that collects the transmitted light that has passed through the rotation analyzer 31, and a detector that detects the intensity of the transmitted light that is collected by the lens 33 and supplied through the fiber. 35. In the pretilt angle measurement, the rotation analyzer 31 is set in a state of orthogonal Nicols with respect to the polarizer 25. For example, when the polarizer 25 is set to 45 degrees with respect to the transmission measurement surface, the rotation analyzer 31 is set to 135 degrees with respect to the transmission measurement surface. The detector 35 may be a spectroscope, for example.

  The transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3 are supported so as to be movable in the circumferential direction around the measurement position M on the transmission measurement surface so that the irradiation angle of the measurement light and the reception angle of the transmission light can be changed. Has been. The transmission measurement surface is a surface including the transmission measurement light projecting unit 2, the transmission measurement light receiving unit 3, and the measurement position M. In the example of FIG. 1, the transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3 are supported so as to be movable in the circumferential direction around the measurement position M on the XZ plane, and the irradiation angle of the measurement light on the XZ plane And the light receiving angle of transmitted light can be changed.

  In the pretilt angle measurement, the transmission measurement surface including the transmission measurement light projecting unit 2, the transmission measurement light receiving unit 3, and the measurement position M is aligned with the alignment direction (that is, the rubbing direction) of the liquid crystal molecules included in the liquid crystal substrate LC to be measured. Set to align. In order to enable measurement of the respective liquid crystal substrates LC having different alignment directions, the transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3 may be configured to pivot around a vertical line passing through the measurement position M. (Details will be described later).

  The intensity of the transmitted light detected by the detector 35 in the orthogonal Nicol state indicating the polarization state of the transmitted light is input to the control unit 10 configured by a computer, and the transmittance in the orthogonal Nicol state is input by the control unit 10. Calculated. Further, the intensity of the transmitted light is detected a plurality of times by changing the irradiation angle of the measurement light by the transmission measurement light projecting unit 2, and the control unit 10 irradiates the measurement light that maximizes the transmittance in the crossed Nicols state. A pretilt angle is calculated based on the angle. The calculated pretilt angle is displayed on a display unit (not shown), for example.

  The transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3 can be moved in the circumferential direction around the measurement position M on the transmission measurement surface by a drive unit 12 including an actuator such as a motor. Further, it can be turned around a vertical line passing through the measurement position M. The control unit 10 acquires an operation amount of an actuator such as a motor included in the drive unit 12 and calculates an irradiation angle of the measurement light, a direction of the transmission measurement surface, and the like.

  By the way, since the liquid crystal substrate LC is bent by its own weight between the pair of bars 8, the irradiation angle of the measurement light used for calculating the pretilt angle deviates from the actual incident angle, and the calculated pretilt angle has an error. May occur. That is, if the irradiation angle of the measurement light determined from the position of the transmission measurement light receiving unit 3 is treated as the incident angle of the measurement light with respect to the liquid crystal substrate LC on the premise that the liquid crystal substrate LC is flat, the liquid crystal substrate LC is actually bent. The measurement position M is inclined and may cause an error.

  Such a problem becomes more prominent as the liquid crystal substrate becomes larger and thinner. The size of the liquid crystal substrate is 2460 × 2160 mm, for example, as a substrate size called the eighth generation. The thickness of the liquid crystal substrate is generally about 1.0 mm, and further thinning is in progress. For example, when the interval between the bars 8 in the pretilt angle measuring apparatus 1 is about 200 to 500 mm, the deflection amount of such a liquid crystal substrate is about 3 mm at the maximum.

  Therefore, the pretilt angle measuring apparatus 1 includes a tilt measuring optical system 4 for measuring the tilt angle of the measurement position M of the liquid crystal substrate LC, and an error is caused by using the measured tilt angle for calculating the pretilt angle. Is suppressed. The tilt measurement optical system 4 receives the tilt measurement light projecting unit 41 that irradiates the measurement position M of the liquid crystal substrate LC with the tilt detection light L1, and the reflected light L2 of the tilt detection light L1, and receives the reflected light L2. And an inclination measurement light receiving unit 43 for acquiring a position.

  The inclination measurement light projecting unit 41 is an example of a second light projecting unit, and is, for example, a laser light source that outputs laser light. In order to easily identify the light receiving position of the reflected light L2, the tilt detection light L1 is preferably a laser beam having excellent directivity.

  The inclination measurement light receiving unit 43 is an example of a second light receiving unit, for example, an image sensor having a rectangular light receiving surface 432 that spreads two-dimensionally, and detects the light receiving position of the reflected light L2 on the light receiving surface 432. Output to the control unit 10. If the inclination angle of the measurement position M on the transmission measurement surface is to be measured, the light receiving surface 432 may extend at least one-dimensionally. The tilt measurement light receiving unit 43 is not limited to this, and may be a plurality of light receiving elements associated with positions, or may be a single light receiving element movable to each position.

  The tilt measurement optical system 4A according to the first example shown in FIG. 1 includes a mirror 45 and a half mirror 47 in addition to the tilt measurement light projecting unit 41 and the tilt measurement light receiving unit 43.

  The mirror 45 reflects the tilt detection light L1 from the tilt measurement light projecting unit 41 to the liquid crystal substrate LC, and reflects the reflected light L2 from the liquid crystal substrate LC to the tilt measurement light receiving unit 43. For example, the mirror 45 makes the tilt detection light L1 incident vertically (Z direction) on the measurement position M of the liquid crystal substrate LC. When the measurement position M is flat, the reflected light L2 is reflected vertically, and the optical axes of the inclination detection light L1 and the reflected light L2 overlap. On the other hand, when the measurement position M is inclined, the reflected light L2 is reflected in a direction deviated from the vertical, and the optical axes of the inclination detection light L1 and the reflected light L2 do not overlap.

  The mirror 45 includes a tilt measurement position where the tilt detection light L1 is vertically incident on the measurement position M of the liquid crystal substrate LC and a transmission measurement light projecting unit 2 by the drive unit 12 configured to include an actuator such as a motor. And a transmission measurement position that does not hinder transmission measurement by the transmission measurement light receiving unit 3. The control unit 10 moves the mirror 45 to the tilt measurement position during the tilt measurement by the tilt measurement light projecting unit 41 and the tilt measurement light receiving unit 43, and moves the mirror 45 during the transmission measurement by the transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3. Move to the transmission measurement position.

  The half mirror 47 reflects the tilt detection light L 1 from the tilt measurement light projecting unit 41 to the mirror 45 and transmits the reflected light L 2 from the mirror 45 to the tilt measurement light receiving unit 43. The relationship between transmission and reflection of the half mirror 47 with respect to the tilt measurement light projecting unit 41 and the tilt measurement light receiving unit 43 may be reversed.

  FIG. 2 is an explanatory diagram for explaining an optical path of the tilt measurement optical system 4A of FIG. In the drawing, the mirror 45 and the half mirror 47 are not shown, and the optical paths of the tilt detection light L1 and the reflected light L2 are represented by straight lines between the measurement position M and the light receiving surface 432. FIG. 3 is an explanatory diagram for explaining the light receiving surface 432 of the inclination measurement light receiving unit 43. P0 indicates the light receiving position of the reflected light L2 when the measurement position M is flat, and Pt indicates the light receiving position of the reflected light L2 when the measurement position M is inclined.

  The light receiving position P0 of the reflected light L2 when the measurement position M is flat is measured in advance using a flat reference surface and treated as the origin. The tilt measurement light receiving unit 43 is installed such that the light reception position P0 of the reflected light L2 when the measurement position M is flat is located at the center of the light receiving surface 432, for example. The light receiving position Pt of the reflected light L2 when the measurement position M is tilted deviates from the light receiving position P0 according to the degree and direction of the tilt of the measurement position M.

  The control unit 10 calculates the tilt angle of the measurement position M of the liquid crystal substrate LC based on the light receiving position Pt of the reflected light L2 (function as a tilt angle calculation unit). Specifically, the control unit 10 acquires the light receiving position Pt of the reflected light L2 from the inclination measurement light receiving unit 43, calculates the change amounts Δx and Δy from the known light receiving position P0 that is the origin, and the change amount Δx. , Δy and the distance D between the light receiving surface 432 and the measurement position M, for example, the inclination angles θx and θy of the measurement position M are calculated by the following formula 1.

  Here, Δx is a change amount corresponding to the inclination in the X direction, and Δy is a change amount corresponding to the inclination in the y direction. θx is an inclination angle of the measurement position M in the X direction, and θy is an inclination angle of the measurement position M in the Y direction. D is the distance between the measurement position M and the light receiving surface 432.

  Note that the change amounts Δx and Δy of the light receiving position Pt of the reflected light L2 from the light receiving position P0 when the measuring position M is inclined are not only the inclination of the measuring position M but also the height of the measuring position M (that is, Z It is also affected by the direction position. However, when the distance D between the light receiving surface 432 and the measurement position M is sufficiently large, and the tilt detection light L1 is incident at an angle perpendicular to or close to the measurement position M, the influence can be ignored.

  The control unit 10 calculates a pretilt angle based on the calculated inclination angle of the measurement position M, the irradiation angle of the measurement light obtained by measuring the transmitted light, and the polarization state of the transmitted light (as a pretilt angle calculation unit) Function of). In other words, the control unit 10 corrects the pretilt angle using the calculated inclination angle of the measurement position M. Specifically, the control unit 10 calculates the pretilt angle by the following Equation 2 based on the irradiation angle of the measurement light that maximizes the transmittance in the crossed Nicols state and the inclination angle of the measurement position M.

  Here, α is a pretilt angle. ψ is the irradiation angle of the measurement light that maximizes the transmittance in the state of crossed Nicols. θa is an inclination angle of the measurement position M on the transmission measurement surface. φ is the twist angle of the liquid crystal molecules, for example, 90 degrees for the TN mode and 0 degrees for the IPS mode. Ne is the extraordinary refractive index of the liquid crystal molecules, and No is the normal refractive index of the liquid crystal molecules.

  The inclination angle θa of the measurement position M on the transmission measurement surface is calculated based on the inclination angles θx and θy in the X and Y directions. When the transmission measurement surface is the XZ plane as in the example of FIG. 1, the tilt angle θa is the tilt angle θx in the X direction, and only the tilt angle θx in the X direction is used for calculating the pretilt angle. The calculation of the inclination angle θa when the transmission measurement surface rotates around the vertical line passing through the measurement position M will be described later.

  The calculation of the pretilt angle is not limited to the above aspect. For example, when the liquid crystal molecules are in the IPS mode, the retardation is calculated from the intensity of the transmitted light in the parallel Nicol state and the intensity of the transmitted light in the orthogonal Nicol state, and the pretilt angle is calculated from the irradiation angle of the measurement light that maximizes the retardation May be calculated.

  FIG. 4 is an operation flowchart showing a first example of the pretilt angle measuring method according to the embodiment of the present invention.

  First, the inclination angle of the measurement position M of the liquid crystal substrate LC is measured (S11 to S14). Specifically, first, the mirror 45 is inserted into the tilt measurement position (S11). At this time, the control unit 10 outputs a drive command to the drive unit 12 so that the mirror 45 moves to the tilt measurement position. Next, the tilt measurement light projecting unit 41 irradiates the measurement position M with the tilt detection light L1, and the tilt measurement light receiving unit 43 acquires the light receiving position of the reflected light L2 (S12). Next, the control unit 10 calculates the inclination angle of the measurement position M (S13). Here, the inclination angle θa of the measurement position M on the transmission measurement surface is calculated. Next, the mirror 45 is removed from the tilt measurement position (S14). At this time, the control unit 10 outputs a drive command to the drive unit 12 so that the mirror 45 moves to the transmission measurement position.

  Second, the pretilt angle of the liquid crystal molecules of the liquid crystal substrate LC is measured (S15 to S17). Specifically, first, the measurement light is irradiated from the transmission measurement light projecting unit 2 to the measurement position M, and the transmission measurement light receiving unit 3 receives the transmitted light (S15). Here, the intensity of the transmitted light in the crossed Nicols state is acquired as the polarization state of the transmitted light. Next, the control unit 10 calculates a pretilt angle based on the irradiation angle of the measurement light that maximizes the transmittance in the crossed Nicols state (S16), and further corrects the pretilt angle based on the inclination angle of the measurement position M ( S17). Here, for example, the pretilt angle is calculated and corrected by Equation 2 above. The correction may be performed every time the irradiation angle of the measurement light is acquired, or may be performed when calculating the irradiation angle of the measurement light at which the transmittance in the state of crossed Nicols is maximized. It may be performed after the calculation.

  According to the pretilt angle measuring apparatus 1 described above, since the pretilt angle is calculated using the tilt angle of the measurement position M of the liquid crystal substrate LC, it is possible to suppress errors.

  Further, the tilt measurement optical system 4A according to the first example reflects the tilt detection light L1 from the tilt measurement light projecting unit 41 to the measurement position M by the mirror 45 configured to be movable. The reflected light L <b> 2 is reflected to the tilt measurement light receiving unit 43. According to this, the freedom degree of arrangement | positioning of the inclination measurement light projection part 41, the inclination measurement light-receiving part 43, and the half mirror 47 can be raised, and there exists an advantage that the incorporation to the pretilt angle measuring apparatus 1 is easy.

[Second example]
FIG. 5 is a schematic configuration diagram showing a second example of the pretilt angle measuring apparatus 1 according to the embodiment of the present invention. About the structure which overlaps with said example, the same number is attached | subjected and detailed description is abbreviate | omitted.

  In the tilt measurement optical system 4B according to the second example shown in FIG. 5, the tilt measurement light projecting unit 41 obliquely irradiates the measurement position M of the liquid crystal substrate LC with the tilt detection light L1, and the tilt measurement light receiving unit 43. Receives the reflected light L2 reflected obliquely from the measurement position M, and obtains the light receiving position of the reflected light L2. The irradiation direction of the inclination detection light L1 and the light receiving direction of the reflected light L2 are between the vertical (Z direction) and the horizontal (XY plane), for example, an angle of 30 to 60 degrees with respect to the Z direction. The light receiving surface 432 of the tilt measurement light receiving unit 43 faces the optical axis direction of the reflected light L2 so as to receive the reflected light L2 vertically.

  The tilt measurement light receiving unit 43 receives the reflected light L2 at a plurality of positions at different distances from the liquid crystal substrate LC. Specifically, the tilt measurement light receiving unit 43 is configured to be movable in the optical axis direction of the reflected light L2 by the drive unit 12 including an actuator such as a motor. The reflected light L2 is received at each of the two positions having different distances. However, the present invention is not limited to this. For example, the tilt measurement light receiving portions 43 may be arranged at two positions, and the side close to the measurement position M may be detachable from the optical path of the reflected light L2.

  The light receiving position P0 (see FIG. 3) of the reflected light L2 when the measurement position M is flat, which is treated as the origin, is constant, such as the center of the light receiving surface 432, even if the tilt measurement light receiving unit 43 moves. Maintained in position. However, the light receiving position P0 may be different before and after the movement of the inclination measurement light receiving unit 43. The light receiving position Pt of the reflected light L2 when the measurement position M is inclined deviates from the light receiving position P0 that is the origin depending on the degree and direction of the inclination of the measurement position M, but the inclination measurement light receiving unit 43 reflects the reflected light L2. The amount of change Δx, Δy varies depending on the position where the light is received.

  The control unit 10 calculates the tilt angle of the measurement position M of the liquid crystal substrate LC based on the light reception position Pt of the reflected light L2 received by the tilt measurement light receiving unit 43 at each position (function as a tilt angle calculation unit). . The calculated tilt angle of the measurement position M is used to calculate the pretilt angle as described in the first example.

  Specifically, the control unit 10 calculates the change amounts Δx1 and Δy1 from the light receiving position Pt of the reflected light L2 acquired by the tilt measurement light receiving unit 43 at the first position, and the tilt measurement light receiving unit 43 is at the second position. The change amounts Δx2 and Δy2 are calculated from the light receiving position Pt of the reflected light L2 acquired in step S2. Then, the control unit 10 determines the change amounts Δx1, Δy1, Δx2, Δy2, the distance D1 between the light receiving surface 432 and the measurement position M at the first position, and the distance D2 between the light reception surface 432 and the measurement position M at the second position. Based on the above, for example, the inclination angles θx and θy of the measurement position M are calculated by the following mathematical formula 3.

  According to this, the inclination angle θ is calculated from the difference Δ2-Δ1 in the change amount with respect to the difference D2-D1 in the distance between the first position and the second position, and the contribution of the distances D1, D2 itself is suppressed. Therefore, it is possible to suppress the influence of the height of the measurement position M (that is, the position in the Z direction). However, it is assumed that the deviation of the height of the measurement position M is sufficiently smaller than the distances D1 and D2.

  FIG. 6 is an operation flowchart showing a second example of the pretilt angle measuring method according to the embodiment of the present invention.

  First, the inclination angle of the measurement position M on the liquid crystal substrate LC is measured (S21 to S25). Specifically, first, the inclination measurement light receiving unit 43 is moved to the first position (S21). At this time, the control unit 10 outputs a drive command to the drive unit 12 so that the inclination measurement light receiving unit 43 moves to the first position. Next, the tilt measurement light projecting unit 41 irradiates the measurement position M with the tilt detection light L1, and the tilt measurement light receiving unit 43 acquires the light receiving position of the reflected light L2 (S22). Next, the inclination measurement light receiving unit 43 is moved to the second position (S23). At this time, the control unit 10 outputs a drive command to the drive unit 12 so that the inclination measurement light receiving unit 43 moves to the second position. Next, the tilt measurement light projecting unit 41 irradiates the measurement position M with the tilt detection light L1, and the tilt measurement light receiving unit 43 acquires the light receiving position of the reflected light L2 (S24). Next, the control unit 10 calculates the inclination angle of the measurement position M (S25). Here, the inclination angle θa of the measurement position M on the transmission measurement surface is calculated.

  Second, the pretilt angle of the liquid crystal molecules on the liquid crystal substrate LC is measured (S26 to S28). These steps S26 to S28 are the same as S15 to S17 in the first example.

  In the tilt measurement optical system 4B according to the second example described above, the tilt measurement light receiving unit 43 receives the reflected light L2 at a plurality of positions at different distances from the liquid crystal substrate LC, and the control unit 10 at each position. The tilt angle of the measurement position M of the liquid crystal substrate LC is calculated based on the light receiving position of the received reflected light L2. According to this, it is possible to suppress the influence of the height of the measurement position M (that is, the position in the Z direction). Further, since the tilt measuring optical system 4B has a small number of parts, there is an advantage that it can be easily incorporated into the pretilt angle measuring apparatus 1.

[Third example]
FIG. 7 is a schematic configuration diagram showing a third example of the pretilt angle measuring apparatus 1 according to the embodiment of the present invention. About the structure which overlaps with said example, the same number is attached | subjected and detailed description is abbreviate | omitted.

  In the tilt measurement optical system 4C according to the third example shown in FIG. 7, two sets of the tilt measurement light projecting unit 41 and the tilt measurement light receiving unit 43 similar to those in the second example are provided, and the tilt measurement is performed. The light receiving unit 43 receives the reflected light L2 at a plurality of positions having different angles with respect to the liquid crystal substrate LC. In the first set, the first tilt measurement light receiving unit 43A receives the reflected light L2 of the tilt detection light L1 emitted by the first tilt measurement light projecting unit 41A, and in the second set, the second set The second inclination measurement light receiving unit 43B receives the reflected light L2 of the inclination detection light L1 emitted by the inclination measurement light projecting unit 41B.

  The first inclination measurement light projecting unit 41A and the second inclination measurement light projecting unit 41B have different irradiation directions of the inclination detection light L1, and the first inclination measurement light receiving unit 43A and the second inclination measurement light receiving unit 43B. Then, the light receiving direction of the reflected light L2 is different. The irradiation direction of the inclination detection light L1 in the first group and the light reception direction of the reflected light L2 are, for example, an angle of 40 to 70 degrees with respect to the Z direction, and the irradiation direction of the inclination detection light L1 in the second group. The light receiving direction of the reflected light L2 is, for example, an angle of 20 to 50 degrees with respect to the Z direction. However, the angle difference in the irradiation direction of the inclination detection light L1 in the first group and the second group, and the angle difference in the light receiving direction in the reflected light L2 in the first group and the second group are each 20 degrees or more, for example. And

  Each of the first inclination measurement light receiving unit 43A and the second inclination measurement light receiving unit 43B is treated as an origin, and the light reception position P0 (see FIG. 3) of the reflected light L2 when the measurement position M is flat is received, for example. It is installed so as to be located at the center of the surface 432. The light receiving position Pt of the reflected light L2 when the measurement position M is inclined deviates from the light receiving position P0 that is the origin depending on the degree and direction of the inclination of the measurement position M, but the inclination measurement light receiving unit 43 reflects the reflected light L2. The amount of change Δx, Δy varies depending on the angle at which the light is received.

  The control unit 10 calculates the tilt angle of the measurement position of the liquid crystal substrate based on the light receiving position of the reflected light L2 received by the first tilt measurement light receiving unit 43A and the second tilt measurement light receiving unit 43B at each position. (Function as an inclination angle calculation unit). The calculated tilt angle of the measurement position M is used to calculate the pretilt angle as described in the first example.

  Specifically, the control unit 10 calculates the changes Δx1 and Δy1 from the light receiving position Pt of the reflected light L2 acquired by the first inclination measurement light receiving unit 43A, and the reflection acquired by the second inclination measurement light receiving unit 43B. The change amounts Δx2, Δy2 are calculated from the light receiving position Pt of the light L2. Then, the control unit 10 determines the change amount Δx1, Δy1, Δx2, Δy2, the distance D1 between the first tilt measurement light receiving unit 43A and the measurement position M, the light reception angle θ1 of the first tilt measurement light receiving unit 43A, the second Based on the distance D2 between the inclination measurement light receiving unit 43B and the measurement position M and the light reception angle θ2 of the second inclination measurement light reception unit 43B, for example, the inclination angles θx and θy of the measurement position M are calculated by the following Equation 4.

  Regarding θx, the contribution of the distances D1 and D2 itself is suppressed in the same manner as in Equation 3, so that the influence of the height of the measurement position M (that is, the position in the Z direction) can be suppressed. However, it is assumed that the deviation of the height of the measurement position M is sufficiently smaller than the distances D1 and D2. For θy, the average of θy calculated from the change amounts Δy1 and Δy2 is taken.

  FIG. 8 is an operation flowchart showing a third example of the pretilt angle measuring method according to the embodiment of the present invention.

  First, the inclination angle of the measurement position M on the liquid crystal substrate LC is measured (S31, S32). Specifically, first, the tilt detection light L1 is irradiated to the measurement position M from each of the first tilt measurement light projecting unit 41A and the second tilt measurement light projecting unit 41B, and the first tilt measurement light receiving unit 43A. And the light reception position of reflected light L2 is acquired by each of the 2nd inclination measurement light-receiving part 43B (S31). Next, the control unit 10 calculates the inclination angle of the measurement position M (S32). Here, the inclination angle θa of the measurement position M on the transmission measurement surface is calculated.

  Second, the pretilt angle of the liquid crystal molecules on the liquid crystal substrate LC is measured (S33 to S35). These steps S33 to S35 are the same as S15 to S17 in the first example.

  In the tilt measurement optical system 4C according to the third example described above, the first tilt measurement light receiving unit 43A and the second tilt measurement light receiving unit 43B receive the reflected light L2 at a plurality of positions at different angles with respect to the liquid crystal substrate LC. The tilt angle of the measurement position M of the liquid crystal substrate LC is calculated based on the light reception position of the reflected light L2 received and received by the control unit 10 at each position. According to this, there is an advantage that the influence of the height of the measurement position M (that is, the position in the Z direction) can be suppressed without a mechanism for moving the tilt measurement light receiving unit 43.

  In this example, the reflected light L2 is received at a plurality of positions at different angles with respect to the liquid crystal substrate LC by the two tilt measurement light receiving units 43A and 43B. However, the present invention is not limited to this, and one tilt measurement light receiving unit 43 is moved. The reflected light L2 may be received at a plurality of positions having different angles with respect to the liquid crystal substrate LC.

[Fourth example]
FIG. 9 is a schematic configuration diagram showing a fourth example of the pretilt angle measuring apparatus 1 according to the embodiment of the present invention. About the structure which overlaps with said example, the same number is attached | subjected and detailed description is abbreviate | omitted. In the figure, illustration of the light source 21, the detector 35, the control unit 10, and the drive unit 12 is omitted. The tilt measurement optical system 4 may be any of the tilt measurement optical systems 4A to 4C according to the first to third examples.

  In the pretilt angle measurement, the transmission measurement surface including the transmission measurement light projecting unit 2, the transmission measurement light receiving unit 3, and the measurement position M is aligned with the alignment direction (that is, the rubbing direction) of the liquid crystal molecules included in the liquid crystal substrate LC to be measured. It is necessary to set so that they are aligned. However, the alignment direction of the liquid crystal molecules may differ depending on the type of the liquid crystal substrate LC. For example, the orientation direction is not limited to the X direction, and may be the Y direction or may be an arbitrary direction between the X direction and the Y direction. In recent years, the liquid crystal substrate has been increased in size and thickness, and it is difficult to change the direction of the liquid crystal substrate LC placed on the plurality of bars 8.

  Therefore, in the pretilt angle measuring apparatus 1 according to this example, the transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3 are supported so as to be pivotable about a vertical line passing through the measurement position M, so that the transmission measurement surface is measured. The liquid crystal substrates LC that can rotate around a vertical line passing through M and have different alignment directions can be measured.

  The transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3 are respectively supported by rotation support units 52 and 53 that can rotate integrally around a vertical line passing through the measurement position M. Specifically, the lens 23 and the polarizer 25 of the transmission measurement light projecting unit 2 are supported by a rotation support unit 52 positioned below the bar 8, and the rotation analyzer 31 and the lens of the transmission measurement light receiving unit 3 are supported. 33 is supported by a rotation support portion 53 positioned above the bar 8.

  In this example, the tilt measurement light projecting unit 41 and the tilt measurement light receiving unit 43 of the tilt measurement optical system 4 emit the tilt detection light L1 and receive the reflected light L2 within the transmission measurement surface. The optical unit 2 and the transmission measurement light-receiving unit 3 are supported so as to be rotatable around a vertical line passing through the measurement position M. Specifically, the inclination measurement light projecting unit 41 and the inclination measurement light receiving unit 43 are supported together with the transmission measurement light projecting unit 2 on a rotation support unit 52 positioned below the bar 8.

  Because of this configuration, the tilt angle calculated from the amount of displacement in a constant direction on the light receiving surface 432 of the tilt measurement light receiving unit 43 is used for calculating the pretilt angle regardless of the rotational position of the transmission measurement surface. Is done. For example, when the X direction in FIG. 3 is an in-plane direction that rotates together with the transmission measurement surface, the tilt angle θx in the X direction calculated from the change Δx is the pretilt angle as the inclination angle θa of the measurement position M on the transmission measurement surface. Used to calculate

  According to this, the inclination angle calculated from the displacement amount in a certain direction (for example, the inclination angle θx in the X direction calculated from the change amount Δx) is used as the inclination angle θa of the measurement position M on the transmission measurement surface as it is. Since it may be used for calculation of the pretilt angle, there is an advantage that the calculation load can be reduced as compared with a fifth example described later.

[Fifth Example]
FIG. 10 is a schematic configuration diagram showing a fifth example of the pretilt angle measuring apparatus 1 according to the embodiment of the present invention. FIG. 11 is a schematic configuration diagram showing a state where the transmission measuring optical system is turned 90 degrees from the state of FIG. About the structure which overlaps with said example, the same number is attached | subjected and detailed description is abbreviate | omitted. In the figure, illustration of the light source 21, the detector 35, the control unit 10, and the drive unit 12 is omitted. The tilt measurement optical system 4 may be any of the tilt measurement optical systems 4A to 4C according to the first to third examples.

  Also in the pretilt angle measuring apparatus 1 according to the present example, the transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3 can rotate around a vertical line passing through the measurement position M, as in the fourth example. 52, 53.

  However, in this example, the inclination measurement light projecting part 41 and the inclination measurement light receiving part 43 of the inclination measurement optical system 4 are not supported by the rotation support parts 52 and 53, and the transmission measurement light projecting part 2 and the transmission measurement light receiving part. Do not turn with 3. The tilt measurement light projecting unit 41 and the tilt measurement light receiving unit 43 are fixed so as to receive the reflected light L2 by irradiating the tilt detection light L1 within the XZ plane where the deflection of the liquid crystal substrate LC is relatively large, for example.

  Since it is configured in this manner, as shown in FIG. 12, the transmission measurement surface T including the transmission measurement light projecting unit 2, the transmission measurement light receiving unit 3, and the measurement position M, the inclination measurement light projection unit 41, and the inclination In some cases, the measurement light receiving unit 43 and the inclined measurement surface S including the measurement position M intersect each other.

  For this reason, the control part 10 acquires the intersection angle A of the transmission measurement surface T and the inclination measurement surface S (function as an intersection angle acquisition part). Specifically, the control unit 10 acquires an operation amount of an actuator such as a motor included in the drive unit 12, and circumferential direction around the measurement position M of the transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3. And the intersection angle A between the transmission measurement surface T and the tilt measurement surface S is calculated based on the position in the circumferential direction.

  Then, the control unit 10 calculates the inclination angle θa of the measurement position M on the transmission measurement surface T based on the intersection angle A (function as an inclination angle calculation unit). The calculated tilt angle θa of the measurement position M on the transmission measurement surface T is used for calculating the pretilt angle as described in the first example.

  Specifically, the control unit 10 acquires the light receiving position Pt of the reflected light L2 from the tilt measurement light receiving unit 43, calculates the tilt angles θx and θy of the measurement position M based on the change amounts Δx and Δy, and performs the measurement. Based on the inclination angles θx and θy of the position M and the intersection angle A, the inclination angle θa of the measurement position M on the transmission measurement surface T is calculated by the following mathematical formula 5.

  According to this, since the tilt measurement light projecting unit 41 and the tilt measurement light receiving unit 43 are not supported by the rotation support units 52 and 53 and do not rotate together with the transmission measurement light projecting unit 2 and the transmission measurement light receiving unit 3, There is an advantage that the portion related to the rotation can be made compact compared with the example of 4. Moreover, there is an advantage that it is easy to detect the deflection of the liquid crystal substrate LC by making the tilt measurement surface S an XZ plane where the deflection of the liquid crystal substrate LC is relatively large.

  In addition, the inventors of the present application may bend the liquid crystal substrate LC not only in the direction in which the bars 8 are arranged (X direction) but also in the direction in which the bars 8 extend (Y direction) as the bars 8 are bent by their own weight. This is a new problem that we found. In order to solve this problem, in the fifth example among the examples described above, the two-dimensional inclination angles θx and θy of the measurement position M are calculated, and from these, the measurement position M on the transmission measurement surface T is calculated. Is calculated.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art.

DESCRIPTION OF SYMBOLS 1 Pretilt angle measuring apparatus, 10 Control part (An example of an inclination angle calculation part, a pretilt angle calculation part, and an intersection angle acquisition part), 12 Drive part, 2 Transmission measurement light projection part (an example of a 1st light projection part), 21 Light source, 23 lens, 25 polarizer, 3 transmission measurement light projecting unit (an example of a first light receiving unit), 31 rotation analyzer, 33 lens, 35 detector, 4, 4A, 4B, 4C tilt measurement optical system, 41 , 41A, 41B Tilt measurement light projecting part (an example of a second light projecting part), 43, 43A, 43B Tilt measurement light receiving part (an example of a second light receiving part), 432 Light receiving surface, 45 mirror, 47 Half mirror, 52 rotation support part, 53 rotation support part, 8 bar, LC liquid crystal substrate, M measurement position, L1 tilt detection light, L2 reflected light.

Claims (8)

A first light projecting unit that irradiates the measurement position of the liquid crystal substrate with polarized measurement light;
A first light receiving unit that receives transmitted light of the measurement light and acquires a polarization state of the transmitted light;
A second light projecting unit that irradiates the measurement position of the liquid crystal substrate with tilt detection light;
A second light receiving unit that receives reflected light of the tilt detection light and obtains a light receiving position of the reflected light;
An inclination angle calculation unit for calculating an inclination angle of the measurement position of the liquid crystal substrate based on a light receiving position of the reflected light;
A pretilt angle calculator that calculates a pretilt angle of liquid crystal molecules included in the liquid crystal substrate based on an irradiation angle of the measurement light, an inclination angle of the measurement position of the liquid crystal substrate, and a polarization state of the transmitted light; ,
A pretilt angle measuring device. A mirror that reflects the tilt detection light from the second light projecting unit to the liquid crystal substrate and reflects the reflected light from the liquid crystal substrate to the second light receiving unit;
The pretilt angle measuring device according to claim 1. The second light receiving unit receives the reflected light at a plurality of positions at different distances from the liquid crystal substrate,
The tilt angle calculation unit calculates the tilt angle of the measurement position of the liquid crystal substrate based on the light receiving position of the reflected light received at each position.
The pretilt angle measuring device according to claim 1. The second light receiving unit receives the reflected light at a plurality of positions having different angles with respect to the liquid crystal substrate,
The tilt angle calculation unit calculates the tilt angle of the measurement position of the liquid crystal substrate based on the light receiving position of the reflected light received at each position.
The pretilt angle measuring device according to claim 1. The first light projecting unit and the first light receiving unit are supported so as to be rotatable about a vertical line passing through the measurement position.
The pretilt angle measuring device according to claim 1. The second light projecting unit and the second light receiving unit irradiate the tilt detection light in a plane including the first light projecting unit, the first light receiving unit, and the measurement position, and In order to receive reflected light, the first light projecting unit and the first light receiving unit are supported so as to be pivotable around a vertical line passing through the measurement position,
The pretilt angle measuring device according to claim 5. A first surface including the first light projecting unit, the first light receiving unit, and the measurement position; a second surface including the second light projecting unit, the second light receiving unit, and the measurement position; A crossing angle acquisition unit that acquires a crossing angle with the surface of
The tilt angle calculation unit calculates an tilt angle of the measurement position of the liquid crystal substrate in the first plane based on the intersection angle.
The pretilt angle measuring device according to claim 5. Irradiate the measurement position of the liquid crystal substrate with polarized measurement light,
Receiving the transmitted light of the measurement light, obtaining the polarization state of the transmitted light,
Irradiate the tilt detection light to the measurement position of the liquid crystal substrate,
Receiving the reflected light of the tilt detection light, obtaining the light receiving position of the reflected light,
Based on the light receiving position of the reflected light, the inclination angle of the measurement position of the liquid crystal substrate is calculated,
Calculating a pretilt angle of liquid crystal molecules included in the liquid crystal substrate based on an irradiation angle of the measurement light, an inclination angle of the measurement position of the liquid crystal substrate, and a polarization state of the transmitted light;
Pretilt angle measurement method.

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