KR20140111484A - Apparatus for detecting defects of patterned retarder - Google Patents

Apparatus for detecting defects of patterned retarder Download PDF

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Publication number
KR20140111484A
KR20140111484A KR1020130025695A KR20130025695A KR20140111484A KR 20140111484 A KR20140111484 A KR 20140111484A KR 1020130025695 A KR1020130025695 A KR 1020130025695A KR 20130025695 A KR20130025695 A KR 20130025695A KR 20140111484 A KR20140111484 A KR 20140111484A
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South Korea
Prior art keywords
retarder
patterning
primary
polarizing
patterning retarder
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KR1020130025695A
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Korean (ko)
Inventor
김종우
박재현
천정미
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동우 화인켐 주식회사
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Priority to KR1020130025695A priority Critical patent/KR20140111484A/en
Publication of KR20140111484A publication Critical patent/KR20140111484A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/958—Inspecting transparent materials or objects, e.g. windscreens
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/8422—Investigating thin films, e.g. matrix isolation method
    • G01N2021/8438—Mutilayers

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
  • Polarising Elements (AREA)

Abstract

A defect inspection apparatus for a patterning retarder is disclosed. An apparatus for inspecting defects of a patterned retarder according to an embodiment of the present invention includes a patterning retarder and an angle formed between the patterning retarder and a reference axis of the patterning retarder, A first polarizing section arranged so as to be at an angle of 17 to 25 degrees, an illumination section irradiating light at a lower portion of the primary polarizing section, a second polarizing section formed at an upper portion of the patterning retarder, A polarizing portion; And a photographing unit for photographing the patterning retarder through the light passing through the secondary polarization unit.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a patterning retarder defect inspection apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus, and more particularly, to a defect inspection apparatus for a patterned retarder capable of detecting an uneven stain of a patterned retarder (FPR).

In general, a patterned retarder can be applied to a stereoscopic image display apparatus using polarizing glasses to be used for realizing a stereoscopic image. In addition, the patterning retarder is provided on one side of a semi-transmissive LCD or the like to function as a compensation film for optimizing the optical characteristics of the reflective portion and the transmissive portion, respectively, so as to obtain a good discrimination power of the LCD image regardless of the brightness of the external light. . The patterned retarder is also referred to as a birefringent medium or a retardation film.

1 is a perspective view showing a general patterning retarder.

Referring to FIG. 1, the patterned retarder 10 includes a base film 11, an orientation layer 13, and a liquid crystal coating layer 15. Here, the liquid crystal coating layer 15 has a structure in which the first polarization pattern region 21 and the second polarization pattern region 23 have a stripe shape and are repeatedly arranged alternately.

The first polarization pattern region 21 may be formed to circularly polarize the transmitted light and the second polarized light pattern region 23 may be formed to circularly polarize the transmitted light. can do. That is, the liquid crystal coating layer 15 has a structure in which the left-handed circularly polarized light region and the right-handed circularly polarized light region are arranged alternately and repeatedly.

The light transmitted through the first polarizing pattern area 21 passes through the left circularly polarizing film in the user's polarizing glasses and the light transmitted through the second polarizing pattern area 23 passes through the right circularly polarizing film in the user's polarizing glasses. As described above, a stereoscopic image can be realized by forming different images on the user's two eyes through the first polarization pattern area 21 and the second polarization pattern area 23.

On the other hand, if the thickness of the liquid crystal coating layer 15 is not uniformly formed in the process of manufacturing the patterned retarder 10, the patterned retarder 10 may have a stain defect. Therefore, screening work for detecting defective spotting of the patterned retarder 10 and excluding defective products is required. However, if the patterned retarder 10 is photographed in order to detect stain defects of the patterned retarder 10 and then the photographed image is converted into a binary image, the first polarized light pattern region 21 and the second polarization pattern area 23 and the brightness difference generated due to the smear are difficult to distinguish between the first and second polarization pattern areas 23 and 23, it is difficult to accurately detect the smear of the patterning retarder 10.

An embodiment of the present invention is to provide an apparatus for inspecting defects of a patterned retarder that can accurately detect a defective stain of a patterned retarder.

1. An apparatus for defect inspection of patterning retarders according to an embodiment of the present invention includes patterning retarders; A primary polarizing portion formed at a lower portion of the patterning retarder and having an absorption axis formed by the reference axis of the patterning retarder with an angle [theta] of 17 [deg.] To 25 [deg.]; An illumination unit for irradiating light at a lower portion of the primary polarization unit; A secondary polarizing portion formed on the patterning retarder and having an absorption axis perpendicular to the primary polarizing portion; And a photographing unit for photographing the patterning retarder through light passing through the secondary polarizing unit.

2.1, the upper primary polarizing section is disposed such that the angle (?) Formed between the absorption axis and the reference axis of the upper patterning retarder is 19.5 ° to 22.5 °.

In 3. 1, the inspection apparatus of the patterning retarder further includes a detection unit for detecting a defect of the patterning retarder through an image acquired through the above-mentioned image-taking unit.

In 4.1, the upper secondary polarizer is a circular polarized light filter or a linear polarized light filter.

According to the embodiment of the present invention, by disposing the absorption axis of the primary polarization section at an angle of 17 ° to 25 ° with respect to the reference axis of the patterning retarder, a first image of the liquid crystal coating layer The difference in brightness is hardly observed at the boundary between the polarization pattern area and the second polarization pattern area, and only the difference in brightness due to the smear can be mainly displayed. Therefore, the patterning retarder can be accurately detected.

1 is a perspective view showing a general patterning retarder.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pattern inspecting apparatus.
3 is a diagram showing the arrangement relationship of a primary polarizer, a patterning retarder, and a secondary polarizer in a defect inspection apparatus according to an embodiment of the present invention.
Figure 4 illustrates a patterned retarder according to one embodiment of the present invention.
5 is a view showing a state in which an absorption axis of a primary polarization section according to an embodiment of the present invention is cut so as to form a predetermined angle? With respect to a reference axis of a patterning retarder.
6 is a diagram showing the degree of visibility of a stain according to a change in an angle [theta] formed between an absorption axis of a primary polarizing portion and a reference axis of a patterning retarder, in an embodiment of the present invention.
FIG. 7 is a graph showing the relationship between the photographed image, the binary image, and the brightness graph of the patterning retarder when the angle θ formed by the absorption axis of the primary polarizing portion with the reference axis of the patterning retarder is 21 ° according to an embodiment of the present invention. Fig.
FIG. 8 is a diagram showing a photographed image, a binary image, and a brightness graph of a patterning retarder when the angle θ formed between the absorption axis of the primary polarizing section and the reference axis of the patterning retarder is 12 °;
FIG. 9 is a view showing a photographed image, a binary image, and a brightness graph of the patterning retarder when the angle? Formed by the absorption axis of the primary polarizing section with the reference axis of the patterning retarder is 30 °;

Hereinafter, a specific embodiment of the defect inspecting apparatus of the patterning retarder of the present invention will be described with reference to FIGS. 2 to 9. However, this is an exemplary embodiment only and the present invention is not limited thereto.

In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intention or custom of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

The technical idea of the present invention is determined by the claims, and the following embodiments are merely a means for efficiently describing the technical idea of the present invention to a person having ordinary skill in the art to which the present invention belongs.

FIG. 2 is a view schematically showing the structure of a defect inspection apparatus of a patterning retarder according to an embodiment of the present invention. FIG. 3 is a schematic block diagram of a defect inspection apparatus according to an embodiment of the present invention, The retarder and the secondary polarizer. Hereinafter, a defect inspection apparatus according to an exemplary embodiment of the present invention detects an unevenness defect of the patterned retarder. However, the present invention is not limited thereto, and the defect inspection apparatus may include a patterning retarder It is needless to say that various defects other than the smudge defect can be detected.

2 and 3, the defect inspection apparatus 100 includes a patterning retarder 102, an illumination unit 104, a primary polarization unit 106, a secondary polarization unit 108, a photographing unit 110, And a detection unit 112.

The patterning retarder 102 includes a base film 121, an orientation layer 123, and a liquid crystal coating layer 125, as shown in Fig. The liquid crystal coating layer 125 is provided with a first polarizing pattern region 127 for circularly polarizing the light passing through the primary polarizing section 106 and a second polarizing pattern 127 for polarizing the light having passed through the primary polarizing section 106 The pattern region 129 is formed in a stripe shape and alternately repeatedly formed.

The illumination unit 104 irradiates light to acquire an image of the patterned retarder 102. The illumination unit 104 may include various light source devices such as an LED lamp, a fluorescent lamp, an incandescent lamp, and a halogen lamp Can be used. The illumination unit 104 may be positioned below the primary polarization unit 106.

The primary polarization section 106 is disposed in parallel with the patterned retarder 102 between the illumination section 104 and the patterned retarder 102. The linear polarization filter PL may be used as the primary polarization section 106. In this case, the primary polarizer 106 transmits only light in a certain direction among the lights emitted from the illumination unit 104, and blocks light in the other directions.

The primary polarization section 106 is arranged so that its absorption axis is at a predetermined angle? With the reference axis of the patterned retarder 102. The reference axis of the patterning retarder 102 refers to an axis with respect to the longitudinal direction of the first polarization pattern area 127 and the second polarization pattern area 129. For example, the primary polarization section 106 may be arranged so that its absorption axis is at an angle of 17 ° to 25 ° with respect to the reference axis of the patterned retarder 102. However, the present invention is not limited to this, and the primary polarization section 106 may be attached to the illumination section 104 after the absorption axis is cut at an angle of 17 to 25 degrees with the reference axis of the patterned retarder 102 have. This will be described with reference to FIG.

Referring to FIG. 5, the absorption axis of the primary polarizer according to an embodiment of the present invention is cut so as to form a predetermined angle (?) With the reference axis of the patterning retarder. The primary polarizing section 106 can be formed by cutting the polarizing film 114 so as to form a predetermined angle? With reference to a direction perpendicular to the stretching direction of the polarizing film 114. At this time, the cut primary polarizing portion 106 may be attached to the illumination portion 104. The absorption axis of the cut primary polarizing portion 106 forms a predetermined angle? With the reference axis of the patterned retarder 102. That is, according to an embodiment of the present invention, the primary polarizing section 106 can be disposed by rotating the absorption axis to a predetermined angle (?) With the reference axis of the patterning retarder 102, The primary polarization section 106 cut to form a predetermined angle? May be attached to the illumination section 104 with reference to the direction perpendicular to the stretching direction of the film 114.

The secondary polarizing portion 108 is disposed in parallel with the patterning retarder 102 between the patterning retarder 102 and the photographing portion 110. The secondary polarization section 108 is disposed orthogonal to the primary polarization section 106. At this time, the secondary polarization section 108 may be attached to the photographing section 110 in a state of being orthogonal to the primary polarization section 106.

The secondary polarization section 108 is arranged to be orthogonal to the primary polarization section 106 according to the angle? Between the patterned retarder 102 and the primary polarization section 106. The secondary polarizer 108 may use a circular polarized light filter, but the present invention is not limited thereto, and a linear polarized light filter can also be used.

The photographing unit 110 photographs the patterned retarder 102 through the light transmitted through the secondary polarization unit 108 to acquire an image of the patterned retarder 102.

The detection unit 112 processes the image photographed by the photographing unit 110 to detect defects in the patterned retarder. For example, the detection unit 112 may convert an image acquired through the imaging unit 110 into a binary image, and then detect a defect of the patterned retarder 102 through the binary image. Here, when the primary polarization section 106 is disposed such that the absorption axis of the primary polarization section 106 and the reference axis of the patterned retarder 102 are in the range of 17 ° to 25 °, The brightness difference is hardly observed at the boundary between the first polarization pattern area 127 and the second polarization pattern area 129 of the liquid crystal coating layer 125 and the brightness difference due to the smear of the patterned retarder 102 The patterned retarder 102 can be accurately detected. This will be described later with reference to FIGS. 6 to 9.

The detection unit 112 may determine that the patterning retarder 102 is defective if the detected smear through the binary image of the patterning retarder 102 exceeds a certain level. For example, the detection unit 112 may determine that the patterning retarder 102 is defective when the number of spots in the binary image of the patterning retarder 102 exceeds a predetermined number or a speck of a predetermined size or larger is detected have. However, the criterion by which the detection unit 112 detects the bad patterning retarder 102 through the stain appearing in the binary image of the patterning retarder 102 is not particularly limited.

6 is a graph showing the degree of visibility of a stain according to a change in an angle? Formed between the absorption axis of the primary polarizing portion and the reference axis of the patterning retarder, in an embodiment of the present invention. Here, the change in brightness of the stain photographed in the specific region was measured while changing the angle (?) Formed between the absorption axis of the primary polarizing section 106 and the reference axis of the patterned retarder 102 by 1 deg. The signal value shown in FIG. 6 means a gray level according to the brightness of the stain.

6, when the angle θ between the absorption axis of the primary polarizer 106 and the reference axis of the patterned retarder 102 is in the range of 17 ° to 25 °, when the signal value of the speckle is 30 The above values can be seen. Particularly, when the angle (?) Formed by the absorption axis of the primary polarizing section (106) with the reference axis of the patterning retarder (102) is in a range of 19.5 to 22.5, And the angle θ formed by the absorption axis of the primary polarization section 106 with the reference axis of the patterned retarder 102 is 21 °, it can be seen that the signal value of the smear is the highest at 68. Therefore, when the angle of the absorption axis of the primary polarization section 106 with the reference axis of the patterned retarder 102 is 21 degrees, the visibility of the stain is most excellent.

FIG. 7 is a graph showing the relationship between the photographed image, the binary image, and the brightness graph of the patterning retarder when the angle θ formed by the absorption axis of the primary polarizing portion with the reference axis of the patterning retarder is 21 ° according to an embodiment of the present invention. Fig.

FIG. 7A shows an image of the patterning retarder 102 taken by the photographing unit 110. FIG. 7A, when the angle formed by the absorption axis of the primary polarizing portion 106 and the reference axis of the patterning retarder 102 is 21 DEG, the patterning retarder 102, The contrast between the first polarized light pattern area 127 and the second polarized light pattern area 129 of the liquid crystal coating layer 125 does not clearly appear in the photographed image of the first polarized light pattern area 127 and the second polarized light pattern area 129 ) Are not well distinguished.

FIG. 7B shows an image obtained by converting the photographed image into a binary image. 7B, the contrast between the first polarization pattern area 21 and the second polarization pattern area 23 of the liquid crystal coating layer 125 in the photographed image shown in FIG. As a result, the difference in brightness between the first and second polarization pattern areas 21 and 23 of the liquid crystal coating layer 125 is hardly observed in the binary image of the patterned retarder 102 have. At this time, only the difference in brightness due to the smear of the patterning retarder 102 appears mainly in the binary image, so that the smear of the patterning retarder 102 can be accurately discriminated.

FIG. 7C shows a brightness graph showing the brightness change of the binary image in gray level. As shown in the figure, the brightness graph does not show the brightness change periodically, and the brightness change rapidly occurs in the specific region. That is, since the brightness difference is hardly observed at the boundary between the first polarization pattern area 21 and the second polarization pattern area 23 of the liquid crystal coating layer 125 in the binary image of FIG. 7 (b) The change does not occur periodically, and the change in brightness due to the smear of the liquid crystal coating layer 125 mainly occurs. Therefore, when the angle (?) Formed by the absorption axis of the primary polarizing section with the reference axis of the patterning retarder is 21 DEG, the patterning retarder 102 can be accurately detected.

Comparative Example

8 and 9 are comparative examples according to the embodiment of the present invention. When the angle (?) Formed between the absorption axis of the primary polarizing portion and the reference axis of the patterning retarder is 12 degrees or 30 degrees, A still image, a binary image, and a brightness graph.

Figs. 8 and 9A show images taken by the patterning retarder 102. Fig. 8A and 9A, the photographed image of the patterned retarder 102 includes the first and second polarization pattern regions 127 and 129 of the liquid crystal coating layer 125, It can be seen that the first polarizing pattern area 127 and the second polarizing pattern area 129 are well distinguished.

Figs. 8 and 9B show images obtained by converting a photographed image into a binary image. 8 and 9 (b), the first polarization pattern area 21 and the second polarization pattern area 23 of the liquid crystal coating layer 125 in the photographed images of FIGS. 8 and 9 (a) As a result, the brightness difference between the first and second polarization pattern regions 21 and 23 of the liquid crystal coating layer 125 is clearly visible in the binary image. At this time, in the binary image, the difference in brightness between the boundaries between the first and second polarization pattern regions 21 and 23 of the liquid crystal coating layer 125 and the difference in brightness due to the patterning retarder 102 coexist So that the patterned retarder 102 can not be accurately distinguished.

8 and 9 (c), a brightness graph showing the brightness change of the binary image in gray level is shown. Referring to FIGS. 8 and 9C, a brightness change periodically appears in the brightness graph. That is, since the brightness difference is clearly displayed at the boundary between the first polarization pattern area 21 and the second polarization pattern area 23 of the liquid crystal coating layer 125 on the binary image, the brightness change also appears periodically in the brightness graph. Accordingly, it is impossible to clearly distinguish the brightness change due to the smear of the liquid crystal coating layer 125 in the brightness graph. As described above, when the angle (?) Formed by the absorption axis of the primary polarizing section with the reference axis of the patterning retarder is outside the range of 17 to 25 degrees, it is possible to detect that the patterned retarder 102 can not be accurately detected can see.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by equivalents to the appended claims, as well as the appended claims.

102: patterning retarder 104: illumination part
106: primary polarization section 108: secondary polarization section
110: photographing unit 112: detecting unit
121: base film 123: alignment layer
125: liquid crystal coating layer 127: first polarizing pattern area
129: second polarized light pattern area

Claims (4)

Patterning retarder;
A primary polarizing portion formed at a lower portion of the patterning retarder and having an absorption axis formed by the reference axis of the patterning retarder with an angle [theta] of 17 [deg.] To 25 [deg.];
An illumination unit for irradiating light at a lower portion of the primary polarization unit;
A secondary polarizing portion formed on the patterning retarder and having an absorption axis perpendicular to the primary polarizing portion; And
And a photographing unit for photographing the patterning retarder through light passing through the secondary polarizing unit.
The method according to claim 1,
Wherein the primary polarizer comprises:
Wherein an angle (?) Formed between the absorption axis and the reference axis of the patterning retarder is 19.5 ° to 22.5 °.
The method according to claim 1,
The defect inspection apparatus of the patterning retarder may further comprise:
Further comprising: a detector for detecting a defect of the patterning retarder through an image acquired through the photographing unit.
The method according to claim 1,
The secondary polarizing unit includes:
A circularly polarized light filter or a linearly polarized light filter.

KR1020130025695A 2013-03-11 2013-03-11 Apparatus for detecting defects of patterned retarder KR20140111484A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022163381A1 (en) * 2021-01-27 2022-08-04 住友化学株式会社 Defect inspection method and defect inspection device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022163381A1 (en) * 2021-01-27 2022-08-04 住友化学株式会社 Defect inspection method and defect inspection device

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