JP2006250631A - Inspection method and inspection device for optical compensating sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and precisely inspect an optical compensation sheet by controlling the inspection light amount, while meeting the constitution of the actual applied state of the optical compensation sheet to the liquid crystal panel. <P>SOLUTION: The optical compensation sheet with an optical anisotropic characteristics is inserted between a pair of polarizers arranged orthogonally with polarization axes, and the reference phase difference sheet of polymer material within-surface phase difference, equivalent to the optical compensation sheet, is inserted between the optical compensation sheet and the polarizer plate so as to compensate the within-surface phase difference of the optical compensation sheet. Then one polarizer is irradiated from the light source, and the light transmitted from the other polarizer is inspected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inspection method and an inspection apparatus for an optical compensation sheet applied for improving the display performance of an image display element using birefringence, such as widening the viewing angle of a liquid crystal display panel.

  In recent liquid crystal panels, for the purpose of improving display performance such as widening the viewing angle, a uniaxial retardation sheet or a disco with a fixed orientation of the transparent support is fixed between the liquid crystal cell and the polarizing plate on one or both sides. An optical compensation sheet having optical anisotropy including a tick liquid crystal is disposed. This retardation sheet and optical compensation sheet have birefringence in the plane and in the thickness direction, and a desired polarization state is obtained by changing the polarization state of incident light.

  It is very important in terms of stable product supply to confirm the retardation value and uniformity in the manufacturing process of the optical compensation sheet. For inspection of the optical compensation sheet, two polarizing plates are arranged on the light source for plane inspection so that the polarization axes are orthogonal to each other, and an optical compensation sheet is arranged between the polarizing plates, and light leakage at this time is observed. It is done by the method of doing.

  At this time, due to the birefringence by the optical compensation sheet, the linearly polarized light formed by the polarizing plate installed on the incident side is disturbed, and if the amount of light leaking from the polarizing plate on the outgoing side increases, this light will inspect the optical compensation sheet. There was a problem that it would be difficult. Therefore, conventionally, inspection is performed while suppressing the amount of leakage light by substantially matching the polarization axis of one of the upper and lower polarizing plates with the slow axis of the uniaxial retardation sheet or the orientation direction of the discotic liquid crystal. . This method is effective for a liquid crystal display panel having a configuration in which the polarization axis of one of the two polarizing plates and the slow axis of the uniaxial retardation sheet or the orientation direction of the discotic liquid crystal are substantially the same. In the case of a liquid crystal display panel having a configuration in which the two do not match, the linearly polarized light is disturbed by the phase difference, so the amount of light leakage increases, and the optical compensation sheet cannot be inspected accurately.

  As a technique for solving such a problem, an apparatus described in Patent Document 1 has been proposed. This apparatus prepares a liquid crystal filter comprising a liquid crystal cell in which a nematic liquid crystal which is a rod-shaped liquid crystal compound is sandwiched between two electrode substrates, and the liquid crystal filter is inspected between a pair of polarizers together with a film to be inspected. In this state, the state of transmitted light with respect to the light projected from the illumination unit onto the polarizer is inspected.

JP 2001-59795 A

  However, since the apparatus described in Patent Document 1 uses a liquid crystal cell, it is necessary to prepare a power source for driving the liquid crystal cell and to control the phase difference of the liquid crystal cell, which makes the configuration and control complicated. End up.

  The present invention has been made in view of the above situation, and can be implemented easily and with high accuracy in accordance with the configuration in the actual application state of the optical compensation sheet to the liquid crystal panel and appropriately controlling the inspection light amount. It is an object to provide an inspection method and an inspection apparatus for an optical compensation sheet.

  An inspection method for an optical compensation sheet according to the present invention is an inspection method for an optical compensation sheet having optical anisotropy, and is provided between a first polarizing plate and a second polarizing plate which are arranged to face each other with their polarization axes orthogonal to each other. When the light is illuminated from the light source to the first polarizing plate in a state where the optical compensation sheet and the canceling phase difference sheet for canceling out the in-plane retardation of the optical compensation sheet are inserted, The optical compensation sheet is inspected based on light emitted from the second polarizing plate.

  In the inspection method of the optical compensation sheet of the present invention, the optical compensation sheet is a uniaxial or biaxial retardation sheet, and the canceling retardation sheet has a slow axis of the slow axis of the optical compensation sheet. Are arranged so as to be orthogonal to each other.

  In the inspection method of the optical compensation sheet of the present invention, the optical compensation sheet has an in-plane retardation direction in which an in-plane retardation direction coincides with a polarization axis of the first polarizing plate, and an in-plane retardation direction. A second anisotropic layer that intersects with the polarization axis of the first polarizing plate, and the retardation phase sheet has a slow axis that is in an in-plane retardation direction of the second anisotropic layer. Are arranged so as to be orthogonal to each other.

  In the inspection method for the optical compensation sheet of the present invention, the first anisotropic layer is a transparent support, and the second anisotropic layer is a discotic liquid crystal layer.

  In the method for inspecting an optical compensation sheet of the present invention, the canceling phase difference sheet is disposed between the second polarizing plate and the optical compensation sheet, the second polarizing plate and the canceling phase difference sheet, The optical compensation sheet is inspected based on light emitted from the second polarizing plate in a state where the first polarizing plate and the optical compensation sheet are inclined relative to each other from a parallel state.

  An inspection apparatus for an optical compensation sheet according to the present invention is an inspection apparatus for an optical compensation sheet having optical anisotropy, and includes a light source, a first polarizing plate disposed above the light source, and the first polarizing plate. Above, a second polarizing plate disposed so that a polarization axis is orthogonal to a polarizing axis of the first polarizing plate, and the optical compensation disposed between the first polarizing plate and the second polarizing plate A canceling phase difference sheet disposed between the sheet and the first polarizing plate or the second polarizing plate for canceling out the in-plane retardation of the optical compensation sheet.

  In the inspection apparatus for an optical compensation sheet of the present invention, the optical compensation sheet is a uniaxial or biaxial retardation sheet, and the canceling retardation film has a slow axis of the slow axis of the optical compensation sheet. Are arranged so as to be orthogonal to each other.

  In the inspection apparatus for an optical compensation sheet of the present invention, the optical compensation sheet has a first anisotropic layer whose in-plane retardation direction coincides with the polarization axis of the first polarizing plate, and an in-plane retardation direction. A second anisotropic layer that intersects with the polarization axis of the first polarizing plate, and the retardation phase sheet has a slow axis that is in an in-plane retardation direction of the second anisotropic layer. Are arranged so as to be orthogonal to each other.

  In the optical compensation sheet inspection apparatus of the present invention, the first anisotropic layer is a transparent support, and the second anisotropic layer is a discotic liquid crystal layer.

  In the inspection apparatus for an optical compensation sheet of the present invention, the canceling phase difference sheet is disposed between the second polarizing plate and the optical compensation sheet, the second polarizing plate and the canceling phase difference sheet, Each of the first polarizing plate and the optical compensation sheet is configured to be relatively tiltable from a parallel state.

  The inspection apparatus for an optical compensation sheet of the present invention includes an inspection unit that detects light emitted from the second polarizing plate and inspects the optical compensation sheet based on the light.

  According to the present invention, a method for inspecting an optical compensation sheet that can be carried out simply and with high accuracy in accordance with the configuration of an optical compensation sheet in an actual application state on a liquid crystal panel and appropriately controlling the amount of inspection light, and An inspection device can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
An optical compensation sheet inspection method and inspection apparatus according to the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of an optical compensation sheet inspection apparatus for explaining a first embodiment of the present invention. FIG. 2 is a schematic diagram showing a stacked state of a set to be inspected that is an inspection target of the optical compensation sheet inspection apparatus for explaining the first embodiment of the present invention, and (a) is a side view of the set to be inspected. FIG. 4B is a plan view schematically showing the polarization axis or slow axis of each laminate.

  As shown in FIG. 1, a tray 14 that holds a set S to be inspected is disposed on a base 18 of the inspection apparatus 10. A base 12 is installed on the pedestal 18 and holds the light receiving unit 16 above the inspection target set S so as to be movable in a direction parallel to the normal line of the inspection target set S. A planar inspection light source 15 is embedded in the tray 14 so as to be in contact with the inspection target set S at a portion where the inspection target set S is placed. The planar inspection light source 15 illuminates the inspection target set S with light from below. An inspection device (not shown) that inspects the optical compensation sheet 23 based on the light detected here is connected to the light receiving unit 16.

  As shown in FIG. 2, a polarizing plate 21 (corresponding to a first polarizing plate in claims) and a polarizing plate 22 (corresponding to claims) on the planar inspection light source 15 so that the polarization axes are orthogonal to each other. (Corresponding to the second polarizing plate) are arranged opposite to each other. An optical compensation sheet 23 (in this embodiment, a uniaxial retardation sheet having an in-plane retardation of 120 nm) is disposed between the pair of polarizing plates 21 and 22. The optical compensation sheet 23 is arranged so that the angle formed between the slow axis and the polarization axes of the polarizing plates 21 and 22 is 45 °, but this angle is not limited to this. Further, a uniaxial retardation sheet 25 having the same in-plane retardation 120 nm as the optical compensation sheet 23 is inserted and disposed between the polarizing plate 22 and the optical compensation sheet 23. The uniaxial retardation sheet 25 is inserted and arranged so that the slow axis thereof is orthogonal to the slow axis of the optical compensation sheet 23. Thereby, the uniaxial retardation sheet 25 functions as a canceling retardation sheet that cancels out the in-plane retardation of the optical compensation sheet 23.

  In the inspection apparatus 10, an optical compensation sheet 23 and a uniaxial retardation sheet 25 functioning as a canceling retardation sheet are inserted between a polarizing plate 21 and a polarizing plate 22 which are opposed to each other with their polarization axes orthogonal to each other. In this state, the light from the planar inspection light source 15 emitted from the polarizing plate 22 is detected by the light receiving unit 16, and the optical compensation sheet 23 is inspected based on the detected light. At this time, since the in-plane retardation of the optical compensation sheet 23 is canceled by the uniaxial retardation sheet 25, even if the slow axis of the polarizing plate 21 and the slow axis of the optical compensation sheet 23 do not substantially coincide with each other, The inspection can be performed in a state where leakage light caused by the optical anisotropy of the optical compensation sheet 23 is suppressed. Further, according to this apparatus, the optical compensation sheet can be inspected by a method close to the usage pattern of the liquid crystal display panel having a configuration in which the slow axis of the polarizing plate 21 and the slow axis of the optical compensation sheet 23 intersect. Further, according to this apparatus, the above-described effect can be obtained only by providing the uniaxial retardation sheet 25 between the optical compensation sheet 23 and the polarizing plate 22, and therefore the apparatus configuration and control are facilitated.

  Needless to say, the uniaxial retardation sheet 25 preferably has no defects and is excellent in uniformity. Further, as a material of the uniaxial retardation sheet 25, a polymer material having optical anisotropy can be applied.

  As the light receiving unit 16, a CCD type or MOS type image sensor or the like can be generally used.

  Further, the planar inspection light source 15 is a light source that irradiates projection light that projects a defective portion of the optical compensation sheet 23 to be inspected, and is not limited as long as it is a projection light source having a spectrum in the visible range. A white light source is preferred.

  In the above description, the uniaxial retardation sheet 25 is provided between the optical compensation sheet 23 and the polarizing plate 22. However, the uniaxial retardation sheet 25 is provided between the optical compensation sheet 23 and the polarizing plate 21. Similar effects can be obtained with the provided configuration. The optical compensation sheet 23 is a uniaxial retardation sheet. However, even if it is a biaxial retardation sheet, the same effect can be obtained.

(Second embodiment)
In the present embodiment, an example in which the optical compensation sheet to be inspected is different from that in the first embodiment will be described.
FIG. 3 is a schematic diagram showing a stacking state of a set S1 to be inspected that is an inspection target of the inspection apparatus for explaining the second embodiment of the present invention, (A) is a side view of the set to be inspected, (B) is a top view which shows typically the polarization axis of each laminated body, a slow axis, an in-plane phase difference direction, etc. FIG. In addition, about the structure of an inspection apparatus, the structure similar to 1st embodiment is applied.

  As shown in FIG. 3, a polarizing plate 31 (corresponding to the first polarizing plate in the claims) and a polarizing plate 32 (corresponding to the claims) above the light source 15 for plane inspection so that the polarization axes are orthogonal to each other. (Corresponding to the second polarizing plate) are arranged opposite to each other. An optical compensation sheet 33 to be inspected is disposed between the pair of polarizing plates 31 and 32.

  The optical compensation sheet 33 includes a transparent support 33a that is a first anisotropic layer having optical anisotropy, and a discotic liquid crystal 33b having a fixed orientation that is a second anisotropic layer. .

  The slow axis of the transparent support 33 a substantially coincides with the slow axis of the polarizing plate 31. The in-plane maximum phase difference direction in which the in-plane retardation of the discotic liquid crystal 33b is maximum (here, 40 nm) intersects with the slow axis of the transparent support 33a.

  Further, a uniaxial retardation sheet 35 having the same in-plane retardation 40 nm as the in-plane maximum retardation of the discotic liquid crystal 33 b is inserted between the polarizing plate 32 and the optical compensation sheet 33. The uniaxial retardation sheet 35 is inserted and arranged so that the slow axis thereof is orthogonal to the in-plane maximum retardation direction of the discotic liquid crystal 33b. Thereby, the uniaxial retardation sheet 35 functions as a canceling retardation sheet that cancels out the in-plane retardation of the optical compensation sheet 33.

  According to the present embodiment, even with an optical compensation sheet (such as an optical compensation sheet for an OCB mode liquid crystal display panel) in which the directions of the in-plane retardation of the two layers do not match, light leakage can be suppressed and an accurate inspection can be performed. it can.

(Third embodiment)
FIG. 4 is a diagram showing a schematic configuration of an optical compensation sheet inspection apparatus for explaining a third embodiment of the present invention. FIG. 5 is a conceptual diagram showing a stacked state of an inspection target set S2 to be inspected by the optical compensation sheet inspection apparatus for explaining the third embodiment of the present invention, and FIG. Side views (B) are plan views schematically showing the polarization axis, slow axis, in-plane retardation direction, and the like of each laminate.

  As shown in FIG. 4, a tray 44 that holds a set S <b> 2 to be inspected is disposed on a base 48 of the inspection apparatus 40. The tray 44 is held so that the arm 44a extending from the tray 44 is tilted and can be released with the tilt axis 43a of the support block 43 fixed to the pedestal 48 as a central axis. The tilt center axis of the tilt shaft 43a passes through the center of the surface of the set S2 to be inspected. A base 42 is installed on the pedestal 48, and holds the light receiving unit 46 above the set S2 to be inspected. A polarizing plate 52 (corresponding to the second polarizing plate in the claims) and a uniaxial retardation sheet 55 are in parallel with the polarizing plate 52 up between the light receiving unit 46 and the inspection target set S2. And is held by an arm 49 extending from the base 48. The light receiving unit 46 is held so as to be movable in a direction parallel to the normal line of the polarizing plate 52 and the uniaxial retardation sheet 55. A flat inspection light source 45 is embedded in the tray 44 so as to be in contact with the inspection target set S2 at a portion where the inspection target set S2 is placed. The planar inspection light source 45 illuminates the inspection target set S2 from below.

  As shown in FIG. 5, a polarizing plate 51 (corresponding to the first polarizing plate in the claims) is disposed on the planar inspection light source 45, and the slow axis of the polarizing plate 51 is the slow axis of the polarizing plate 52. Orthogonal to the phase axis. An optical compensation sheet 53 to be inspected is disposed on the polarizing plate 51.

  The optical compensation sheet 53 includes a transparent support 53a that is a first anisotropic layer having optical anisotropy, and a discotic liquid crystal 53b that is a second anisotropic layer and in which the orientation is fixed. . Here, the arrangement in the thickness direction of the discotic liquid crystal 53b is, for example, a hybrid alignment in which the tilt angle near the transparent support 53a is about 10 ° and the tilt angle gradually rises at about 40 ° on the opposite side. .

  The slow axis of the transparent support 53 a substantially coincides with the slow axis of the polarizing plate 51. The in-plane maximum phase difference direction in which the in-plane phase difference of the discotic liquid crystal 53b is maximum (here, 35 nm) intersects with the slow axis of the transparent support 53a.

  The uniaxial retardation sheet 55 has an in-plane retardation of 70 nm larger than the maximum in-plane retardation of 35 nm of the discotic liquid crystal 53b, and is held by the arm 49 so as to be parallel to the polarizing plate 52. The light source 45 and the light receiving unit 46 are disposed on the optical axis. At this time, the slow axis of the uniaxial retardation sheet 55 is held so as to be orthogonal to the in-plane maximum phase difference direction of the discotic liquid crystal 53b.

The operation of the optical compensation sheet inspection apparatus 40 will be described.
With the inspection target set S2 set on the tray 44, the optical compensation sheet inspection apparatus 40 sets the tray 44 to a predetermined angle (here, 30 °) from a state parallel to the uniaxial retardation sheet 55 and the polarizing plate 52. 4) The state as shown in FIG. Since the uniaxial retardation sheet 55 and the discotic liquid crystal 53b can be adjusted so that the mutual phase difference becomes the same value by changing the relative angle thereof, the in-plane retardation of the uniaxial retardation sheet 55 can be adjusted. Is adjusted to be the same value as the maximum value of 35 nm of the in-plane retardation of the discotic liquid crystal 53 b, thereby canceling the uniaxial retardation sheet 55 to cancel the in-plane retardation of the optical compensation sheet 53. It can function as a phase difference sheet. After the state shown in FIG. 4, the optical compensation sheet inspection apparatus 40 detects light from the planar inspection light source 45 emitted from the polarizing plate 52 by the light receiving unit 46, and based on the detected light, the optical compensation sheet 53. Perform an inspection.

  Thus, according to the optical compensation sheet inspection apparatus 40, the same effect as in the second embodiment can be obtained. Further, since the in-plane retardation of the uniaxial retardation sheet 55 and the in-plane retardation of the discotic liquid crystal 53b can be adjusted to the same value by tilting the tray 44, the optical compensation sheet 53 can be adjusted. When it is replaced with another one, it is not necessary to replace the uniaxial phase difference sheet 55 accordingly, and an efficient inspection becomes possible.

  In the above description, the in-plane retardation of the uniaxial retardation sheet 55 and the in-plane retardation of the discotic liquid crystal 53b are the same by tilting the tray 44 with respect to the uniaxial retardation sheet 55 and the polarizing plate 52. The uniaxial retardation sheet 55 and the polarizing plate 52 are inclined with respect to the tray 44, or both the uniaxial retardation sheet 55 and the polarizing plate 52 and the tray 44 are inclined. Even in this case, the in-plane retardation of the uniaxial retardation sheet 55 and the in-plane retardation of the discotic liquid crystal 53b can be adjusted to be the same value.

  In addition, the inspection direction determined by the position of the light receiving unit 46 is a direction in which the phase difference generated by the discotic liquid crystal 53b is the largest in a state where the tray 44 is inclined, so that the sensitivity is increased and the inspection is performed with higher accuracy. Is possible.

  In the above embodiment, the method for inspecting the optical compensation sheet has been described. However, the present invention can also be applied to the method for inspecting a processed product of a polarizing plate with an optical compensation sheet. FIG. 6 shows a schematic configuration of the optical compensation sheet inspection apparatus in this case, and FIG. 7A is a side view showing the stacking state of the set to be inspected in this case. The polarization axis, slow axis, Or the top view which shows a phase difference direction typically was shown in FIG.7 (B). 6 and 7 differ from FIGS. 4 and 5 in that a glass plate 66 is sandwiched between the polarizing plate 52 and the uniaxial retardation sheet 55, and the polarizing plate 51 is integrated with the optical compensation sheet 53. This is two points.

  By using the inspection apparatus described in the above embodiment for the optical compensation sheet manufacturing process, highly accurate inspection can be easily performed at high speed.

  The inspection method and inspection apparatus of the present invention are not limited to inspection of a viewing angle improving film for liquid crystal, and can be applied to inspection of defects such as a retardation film.

The figure which shows schematic structure of the optical compensation sheet test | inspection apparatus for describing 1st embodiment of this invention The schematic diagram which shows the lamination | stacking state of the to-be-inspected set used as the test object of the optical compensation sheet inspection apparatus for describing 1st embodiment of invention The schematic diagram which shows the lamination | stacking state of the to-be-inspected object set used as the test object of the test | inspection apparatus for describing 2nd embodiment of this invention. The figure which shows schematic structure of the optical compensation sheet inspection apparatus for describing 3rd embodiment of this invention The schematic diagram which shows the lamination | stacking state of the test object set used as the test object of the optical compensation sheet test | inspection apparatus for describing 3rd embodiment of this invention The figure which shows schematic structure of the optical compensation sheet test | inspection apparatus which makes the inspection object the polarizing plate processed goods with an optical compensation sheet | seat Schematic diagram showing the stacking state of a set to be inspected including a polarizing plate processed product with an optical compensation sheet

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical compensation sheet inspection apparatus 12 Base 14 Tray 15 Plane inspection light source 16 Light-receiving part 18 Base 21, 22 Polarizing plate 23 Optical compensation sheet 25 Uniaxial retardation sheet 31, 32 Polarizing plate 33 Optical compensation sheet 33a Transparent support 33b Discotic liquid crystal 35 Uniaxial retardation sheet 40 Optical compensation sheet inspection device 42 Base 43 Support block 43a Inclined shaft 44 Tray 44a Arm 45 Plane inspection light source 46 Light receiving part 48 Base 49 Arms 51, 52 Polarizing plate 53 Optical compensation sheet 53a Transparent support 53b Discotic liquid crystal 55 Uniaxial retardation sheet 61, 62 Polarizing plate 63 Optical compensation sheet 63a Transparent support 63b Discotic liquid crystal 65 Uniaxial retardation sheet 66 Glass plate S Inspected object set S1 Inspected object set S2 Inspected set S3 Inspected pair Elephant set

Claims (11)

An inspection method for an optical compensation sheet having optical anisotropy,
Between the first polarizing plate and the second polarizing plate arranged opposite to each other with their polarization axes orthogonal, the optical compensation sheet, and a canceling phase difference sheet for canceling out the in-plane retardation of the optical compensation sheet, An inspection method for an optical compensation sheet, in which the optical compensation sheet is inspected based on light emitted from the second polarizing plate when light is emitted from a light source to the first polarizing plate in a state in which the light is inserted. An inspection method for an optical compensation sheet according to claim 1,
The optical compensation sheet is a uniaxial or biaxial retardation sheet,
The canceling phase difference sheet is an optical compensation sheet inspection method in which the slow axis is arranged so as to be orthogonal to the slow axis of the optical compensation sheet. An inspection method for an optical compensation sheet according to claim 1,
The optical compensation sheet includes a first anisotropic layer having an in-plane retardation direction coinciding with a polarization axis of the first polarizing plate, and an in-plane retardation direction intersecting a polarization axis of the first polarizing plate. A second anisotropic layer
The method of inspecting an optical compensation sheet, wherein the canceling retardation sheet is arranged so that a slow axis thereof is orthogonal to an in-plane retardation direction of the second anisotropic layer. An inspection method for an optical compensation sheet according to claim 3,
The first anisotropic layer is a transparent support;
A method for inspecting an optical compensation sheet, wherein the second anisotropic layer is a discotic liquid crystal layer. An inspection method for an optical compensation sheet according to any one of claims 1 to 4,
The canceling phase difference sheet is disposed between the second polarizing plate and the optical compensation sheet,
The second polarizing plate and the canceling phase difference sheet, and the first polarizing plate and the optical compensation sheet are emitted from the second polarizing plate in a state where they are inclined relative to each other from a parallel state. A method for inspecting an optical compensation sheet, wherein the optical compensation sheet is inspected based on light to be transmitted. An inspection device for an optical compensation sheet having optical anisotropy,
A light source;
A first polarizing plate disposed above the light source;
A second polarizing plate disposed above the first polarizing plate so that a polarization axis is perpendicular to a polarization axis of the first polarizing plate;
An in-plane position of the optical compensation sheet disposed between the optical compensation sheet and the first polarizing plate or the second polarizing plate disposed between the first polarizing plate and the second polarizing plate. An optical compensation sheet inspection apparatus comprising: a canceling phase difference sheet for canceling a phase difference. An inspection apparatus for an optical compensation sheet according to claim 6,
The optical compensation sheet is a uniaxial or biaxial retardation sheet,
The canceling phase difference sheet is an optical compensation sheet inspection apparatus that is arranged so that its slow axis is orthogonal to the slow axis of the optical compensation sheet. An inspection apparatus for an optical compensation sheet according to claim 6,
The optical compensation sheet includes a first anisotropic layer having an in-plane retardation direction coinciding with a polarization axis of the first polarizing plate, and an in-plane retardation direction intersecting a polarization axis of the first polarizing plate. A second anisotropic layer
The canceling phase difference sheet is an inspection apparatus for an optical compensation sheet that is arranged so that a slow axis thereof is orthogonal to an in-plane phase difference direction of the second anisotropic layer. An inspection apparatus for an optical compensation sheet according to claim 8,
The first anisotropic layer is a transparent support;
An inspection apparatus for an optical compensation sheet, wherein the second anisotropic layer is a discotic liquid crystal layer. An inspection apparatus for an optical compensation sheet according to any one of claims 6 to 9,
The canceling phase difference sheet is disposed between the second polarizing plate and the optical compensation sheet,
An inspection apparatus for an optical compensation sheet, wherein the second polarizing plate and the canceling phase difference sheet, and the first polarizing plate and the optical compensation sheet are configured to be relatively tiltable from a parallel state. An inspection apparatus for an optical compensation sheet according to any one of claims 6 to 10,
An inspection apparatus for an optical compensation sheet, comprising inspection means for detecting light emitted from the second polarizing plate and inspecting the optical compensation sheet based on the light.

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