CN210222403U - Inspection apparatus - Google Patents

Abstract

The utility model provides an inspection device, the angle of the slow axle of absorption axle and the phase difference membrane of the polaroid of the demonstration side to dispose display device is surveyed to the efficiency well. An inspection apparatus for a display device, wherein a retardation film group comprising a plurality of rectangular retardation films is disposed on a transparent substrate, a polarizing plate is disposed thereon, the polarizing plate has an absorption axis, each of the plurality of rectangular retardation films has a slow axis forming a predetermined angle with the absorption axis of the polarizing plate, the slow axis of the rectangular retardation film has a 1 st angle with respect to the slow axis of the rectangular retardation film adjacent to the rectangular retardation film, and the predetermined angle monotonically increases or monotonically decreases from the predetermined angle of the rectangular retardation film existing at a 1 st end of the retardation film group to the predetermined angle of the rectangular retardation film existing at a 2 nd end, which is an end opposite to the 1 st end of the retardation film group.

Description

Inspection apparatus

Technical Field

The present invention relates to a display device having a structure in which a polarizing plate and a retardation film are disposed on a display surface side of the display device to prevent reflection and the like.

Background

In a liquid crystal display device, a TFT substrate in which pixels each including a pixel electrode and a TFT (thin film Transistor) are formed in a matrix and a counter substrate in which a black matrix or the like is formed are opposed to each other with liquid crystal interposed therebetween in a display region. Then, in each pixel, an image is formed by controlling the transmittance of the liquid crystal.

Since liquid crystal can control only polarization, a lower polarizer is disposed on the incident side of light from the backlight to convert the light into linearly polarized light, and an upper polarizer is disposed on the exit side of light from the liquid crystal display panel. On the other hand, for the purpose of viewing the polarized sunglasses in a state of being worn, there are cases where: after the polarized light passes through the liquid crystal display panel, a retardation film is disposed on the light exit side to convert the light into elliptically polarized light.

Patent document 1 describes the following structure: the absorption axis of the lower polarizer, the absorption axis of the upper polarizer, and the slow axis of the retardation film are slightly shifted from the normal angle in relation to the initial alignment axis of the liquid crystal molecules in the liquid crystal display panel, thereby achieving a balance between the viewing angle characteristics and the black display.

On the other hand, in the organic EL display device, an organic EL layer having a light emitting layer is formed for each pixel, and an image is formed by controlling the organic EL layer using a switching TFT and a driving TFT. In an organic EL display device, a polarizing plate and a retardation film are used to prevent reflection of external light.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-126170

SUMMERY OF THE UTILITY MODEL

The liquid crystal display panel is finally assembled in a smart phone, a tablet computer, a mobile phone, and the like in an assembly factory (set maker). In the assembly plant, the overall image quality, such as the contrast of the image, the reflection prevention, etc., is ultimately evaluated. Therefore, additional arrangement of a polarizing plate and a retardation film that affect these characteristics has been conventionally performed in assembly plants.

On the other hand, a polarizing plate, a retardation film, and the like are also essential parts for manufacturers of liquid crystal display panels. If a deviation occurs between the polarization axis of the polarizer and the slow axis of the retardation film on the liquid crystal display panel manufacturer side and the polarization axis of the polarizer and the slow axis of the retardation film on the assembly plant side, the contrast of an image and the reflection of external light are affected.

Therefore, it is necessary for manufacturers of liquid crystal display panels to accurately control the angles of the polarization axis of the polarizing plate and the slow axis of the retardation film. However, in the past, large-scale equipment was required for controlling the angles of the polarizing axis of the polarizing plate and the slow axis of the retardation film, and the efficiency of the inspection work was not sufficient.

The utility model discloses a topic lies in for can easily evaluate the angle of the slow axis of the polarizing axis of polaroid, phase difference membrane of liquid crystal display panel manufacturer side, to the product that has the problem, can reliably carry out pasting again of polaroid, phase difference membrane before the factory shipment.

The problems described above are similar in the organic EL display device. This is because, in the organic EL display device as well, a polarizing plate or a retardation film is used to prevent external light reflection.

The present invention has been made to overcome the above problems, and a representative embodiment is as follows.

(1) An inspection apparatus for a display device, wherein a retardation film group comprising a plurality of rectangular retardation films is disposed on a transparent substrate, and a polarizing plate is disposed on the retardation film group, wherein the polarizing plate has an absorption axis, each of the plurality of rectangular retardation films has a slow axis forming a predetermined angle with the absorption axis of the polarizing plate, the slow axis of the rectangular retardation film has a 1 st angle with respect to the slow axis of the rectangular retardation film adjacent to the rectangular retardation film, and the predetermined angle increases or decreases monotonically from the predetermined angle of the rectangular retardation film existing at a 1 st end of the retardation film group to the predetermined angle of the rectangular retardation film existing at a 2 nd end opposite to the 1 st end of the retardation film group .

(2) The inspection apparatus for a display device according to (1), wherein the predetermined angle of at least one retardation film among the plurality of rectangular retardation films is 45 °.

(3) The inspection apparatus for a display device according to (2), wherein the rectangular retardation film having the predetermined angle of 45 ° is present at a center of the retardation film group.

(4) The inspection device for a display device according to (1), wherein the 1 st angle is 0.5 °.

(5) The inspection apparatus according to (1), wherein the polarizing plate is first bonded to a transparent substrate, and the retardation film group is bonded to the polarizing plate.

Drawings

Fig. 1 is a sectional view of a liquid crystal display device to which the present invention is applied.

Fig. 2 is a view showing directions of an absorption axis of a polarizing plate, a slow axis of a retardation film, and an alignment axis in a TFT substrate and a counter substrate of a liquid crystal display device to which the present invention is applied.

Fig. 3 is a view showing directions of an absorption axis of a polarizing plate, a slow axis of a retardation film, and an alignment axis in a TFT substrate and a counter substrate in an inspection process using the inspection apparatus of the present invention.

Fig. 4 is a graph showing the relationship between the difference between the 1 st angle formed by the absorption axis of the polarizing plate in the 1 st group and the slow axis of the retardation film and the 2 nd angle formed by the absorption axis of the polarizing plate in the 2 nd group and the slow axis of the retardation film, and the luminance in black display.

Fig. 5 is a plan view of the liquid crystal display device.

Fig. 6 is a plan view of a pixel portion of the liquid crystal display device.

Fig. 7 is a sectional view a-a of fig. 6.

Fig. 8 is a schematic cross-sectional view showing an inspection process using the inspection apparatus of the present invention.

Fig. 9 is a perspective view showing a relationship between a retardation film group and a polarizing plate according to the present invention.

Fig. 10 is a plan view showing an inspection state of the present invention.

Fig. 11A is a sectional view of the inspection apparatus.

Fig. 11B is a plan view of the inspection apparatus.

Fig. 12 is a sectional view of another example of the inspection apparatus.

Fig. 13 is a sectional view of still another example of the inspection apparatus.

Fig. 14 is a sectional view of an organic EL display device to which the present invention is applied.

Fig. 15 is a cross-sectional view of an organic EL display device to which the present invention is applied.

Fig. 16 is a cross-sectional view showing the state of inspection of a polarizing plate and a phase difference film used for attaching the present invention to a cover glass (cover glass).

Fig. 17 is a view showing the directions of the absorption axis of the polarizing plate and the slow axis of the retardation film in the inspection step using the inspection apparatus of the present invention.

Description of the reference numerals

10: lower polarizing plate, 11: upper polarizing plate, 12: phase difference film, 20: cover glass, 21: polarizing plate for filter, 22: retardation film for optical filter, 30: orientation axis, 31: polarizing plate absorption axis, 32: retardation film slow axis, 90: display area, 91: scan line, 92: video signal line, 93: pixel, 95: frame area, 100: TFT substrate, 101: 1 base film, 102: base film 2, 103: semiconductor layer, 104: gate insulating film, 105: gate, 106: interlayer insulating film, 107: source, 108: inorganic passivation film, 109: organic passivation film, 110: common electrode, 111: 2 nd interlayer insulating film, 112: pixel electrode, 113: alignment film, 120: through-hole, 125: through hole, 130: through-hole, 150: seal, 160: terminal area, 170: flexible wiring substrate, 200: counter substrate, 201: color filter, 202: black matrix, 203: cover film, 204: alignment film, 300: liquid crystal, 301: liquid crystal molecule, 400: liquid crystal display panel, 500: backlight, 600: organic EL display device, 700: backlight for inspection, 1000: a detector.

Detailed Description

The following describes the present invention in detail with reference to examples. In the following description, a liquid crystal display device will be described, but the present invention can be similarly applied to an organic EL display device.

[ example 1 ]

Fig. 1 is a sectional view of the liquid crystal display device of the present invention in a state assembled as a set. In fig. 1, a liquid crystal display panel 400 is formed of a TFT substrate 100 and a counter substrate 200. As described later, scanning lines, video signal lines, pixels, and the like are formed on the TFT substrate 100. A color filter or a black matrix is formed on the counter substrate 200, and liquid crystal is sandwiched between the TFT substrate 100 and the counter substrate 200.

Since the liquid crystal itself does not emit light, the backlight 500 is disposed on the rear surface. An image is formed by controlling light from the backlight 500 on a pixel-by-pixel basis. Since the liquid crystal can control only polarization, the lower polarizer 10 is disposed on the rear surface of the TFT substrate 100, and converts light from the backlight 500 into linearly polarized light. The polarized light is analyzed by the upper polarizing plate 11, reflected in the control received in the liquid crystal and emitted from the upper polarizing plate 11.

A retardation film 12 is disposed on the upper polarizing plate 11, and converts light emitted from the upper polarizing plate 11 into circularly polarized light. The liquid crystal module is configured from the backlight 500 to the retardation film 12, and is supplied to an assembly factory by a liquid crystal display panel manufacturer.

In the assembly plant, the liquid crystal module is assembled inside the cover glass 20. In the assembly plant, a polarizing plate (hereinafter referred to as a polarizing plate for a filter) 21 and a retardation film (hereinafter referred to as a retardation film for a filter) 22 are disposed on the inner surface of the cover glass 20 in order to prevent reflection of external light. The retardation film 22 for optical filter is disposed so as to face the retardation film 12 disposed in the liquid crystal module. The circularly polarized light passes through the retardation film 22 for a filter on the cover glass 20 side, is converted into linearly polarized light again, passes through the polarizing plate 21 for a filter, passes through the cover glass 200, and is emitted to the outside. The detector (detector)1000 in fig. 1 is used to evaluate the amount of light transmitted for use by the assembly plant in inspection prior to shipment.

With this arrangement, the external light is blocked by the polarizing plate 21 for filter and the retardation film 22 for filter formed on the glass cover side, and the external light is not reflected, thereby making it possible to obtain a screen easy to observe.

Fig. 2 shows absorption axes 31 of the polarizing plates 11 and 21, slow axes 32 of the retardation films 12 and 22, and alignment axes 30 of the alignment films of the TFT substrate 100 and the counter substrate 200, which correspond to the configuration of fig. 1. In the retardation films 12 and 22, the slow axis 32 is in the direction ne in which the refractive index is large, and the direction perpendicular to the slow axis 32 is the direction no in which the refractive index is small. Since the retardation films 12 and 22 are formed by stretching a polymer film, and the stretching direction of the retardation films 12 and 22 is the slow axis 32, the slow axis 32 of the retardation films 12 and 22 may be hereinafter referred to as the stretching direction of the retardation films 12 and 22.

The present embodiment is a liquid crystal display device operating in a so-called e-mode. The liquid crystal display panel is an IPS (In Plane Switching) liquid crystal display panel. The present invention can also be applied to a liquid crystal display device operating in a so-called o-mode, in which case the absorption axis of the polarizing plate, the slow axis of the retardation film, and the alignment axes of the alignment films of the TFT substrate and the counter substrate, which are described below, are rotated by 90 °.

In fig. 2, the absorption axis 31 of the lower polarizer 10 is the horizontal direction (x direction). In this case, in the e-mode, the alignment axis 30 of the TFT substrate 100 is in the vertical direction (y direction). The alignment axis 30 of the counter substrate 200 is also the vertical direction (y direction). The absorption axis 31 of the upper polarizer 11 is also the vertical direction (y-direction). The retardation film 12 attached to the upper polarizing plate 11 is a so-called λ/4 retardation film, and converts linearly polarized light into circularly polarized light by crossing the slow axis 32 and the absorption axis 31 of the upper polarizing plate 11 at 45 degrees. The liquid crystal module side is configured from the lower polarizer 10 to the upper retardation film 12.

In the assembly plant, the filter polarizing plate 21 and the filter retardation film 22 are disposed on the cover glass 20. The retardation film 22 for optical filter is disposed so as to face the retardation film 12 on the liquid crystal module side. The retardation film 22 for optical filter is a so-called λ/4 retardation film, and the slow axis 32 is inclined by 45 ° to the side opposite to the retardation film 12 with respect to the x direction. Thereby, the circularly polarized light is converted into linearly polarized light. The absorption axis 31 of the filter polarizing plate 21 is in the same y direction as the upper polarizing plate 11 on the liquid crystal module side.

In the configuration of fig. 1 and 2, the angle formed by the absorption axis 31 of the upper polarizing plate 11 on the liquid crystal module side and the slow axis of the retardation film 12 needs to be exactly 45 degrees, and the angle formed by the absorption axis 31 of the filter polarizing plate 21 on the cover glass 20 side and the slow axis 32 of the filter retardation film 22 needs to be exactly 45 degrees. However, in practice, the angles formed by the slow axes 32 of the retardation films 12 and 22 on the liquid crystal module side and the glass cover side and the absorption axes 31 of the polarizing plates 11 and 21 are deviated by 45 degrees due to variations in the production of the polarizing plates 11 and 21 or the retardation films 12 and 22, the accuracy of the combination of the polarizing plates 11 and 21 and the retardation films 12 and 22, and the like. The amount of deviation from 45 degrees on the liquid crystal module side and the amount of deviation from 45 degrees on the cover glass side are referred to as offsets (offsets).

If there is an offset, when the liquid crystal module is assembled into a set and display is performed (except when the offsets of the liquid crystal module side and the glass cover side cancel each other), reflection of external light cannot be prevented sufficiently. If the reflection prevention is not sufficiently performed, the contrast is lowered in the display as a suit.

Therefore, in order to exhibit a sufficient antireflection effect as a package in the manufacture of a liquid crystal module, it is necessary to confirm the bias on the liquid crystal module side so that the bias is within a certain range.

Therefore, the method of checking the offset was examined, and the structures shown in fig. 8 to 10 were obtained. The structure of the inspection apparatus shown in fig. 8 is characterized in that: in order to examine the effect of reflection prevention, not reflection but transmission was confirmed.

The optical axis of the inspection apparatus used here has a configuration shown in fig. 3. In the configuration of fig. 3, the configuration on the liquid crystal module side is the same as that shown in fig. 2, and the angle formed by the absorption axis 31 of the upper polarizing plate 11 and the slow axis of the retardation film 12 is exactly 45 degrees. On the other hand, an inspection polarizing plate 51 and an inspection retardation film 52 are provided at a position on the cover glass 20 side in fig. 2. The difference between them is that the polarizing plate 21 of the display device shown in fig. 2 is in a direction parallel to the polarizing plate 11 on the liquid crystal module side, and the polarizing plate 51 of the inspection device shown in fig. 3 is in a direction orthogonal to the polarizing plate 11 on the liquid crystal module side, with respect to the absorption axis direction of the cover glass-side polarizing plate. The angle formed by the polarizing plate and the retardation film can be detected by confirming the depth of the transmitted black display by the axis structure of the inspection apparatus. As will be described in detail later, a plurality of angles formed between the absorption axis 31 of the inspection polarizing plate 51 and the slow axis 32 of the inspection retardation film 52 are formed within a certain range around 45 degrees.

In addition, in order to perform an inspection of the offset by the transmission and to judge the offset by the transmitted light becoming the darkest, as shown in fig. 3, the absorption axis 31 of the inspection polarizing plate 51 is orthogonal to the absorption axis 31 of the upper polarizing plate 11 of the liquid crystal module. For example, when there is no offset of the liquid crystal module, if white display is performed in the liquid crystal module, display in a region where the angle formed by the absorption axis 31 of the inspection polarizing plate 51 and the slow axis 32 of the inspection retardation film 52 is 45 degrees is equivalent to display in black display when the absorption axis 31 of the upper polarizing plate 11 of the liquid crystal module is perpendicular to the absorption axis 31 of the inspection polarizing plate 51.

Next, fig. 4 shows a relationship between the bias and the luminance of the transmitted light in the inspection method shown in fig. 3. The horizontal axis in fig. 4 represents the offset angle (degree), and the vertical axis represents the luminance in black display, and represents an arbitrary unit. The smaller the luminance in the black display, the better. The two retardation films were examined.

In fig. 4, although there is a slight deviation, when the offset angle exceeds 1 degree, an increase in black luminance is observed, and when it exceeds two degrees, the black luminance increases sharply. That is, in a product having an offset of more than two degrees, it is necessary to replace parts of the polarizing plate and the retardation film or to re-attach the polarizing plate and the retardation film.

However, the liquid crystal module side performs the operation of attaching the polarizing plate 11 and the retardation film 12 at the panel manufacturer, and the cover glass 20 side performs the operation of attaching the polarizing plate 21 and the retardation film 22 at the assembly plant. Therefore, in both cases, it is necessary to prevent the polarization axis of the polarizing plate and the slow axis direction of the retardation film from being deviated by 45 degrees.

The present invention can measure the deviation of the crossing angle between the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 easily, particularly at the panel manufacturer side, and can improve the productivity. The present invention is directed to the inspection method and the inspection apparatus of the panel manufacturer side, but as described in embodiment 3, the present invention can also be used for the inspection of the angular misalignment of the combination of the polarizing plate 21 for the optical filter and the phase difference film 22 for the optical filter, which is disposed on the glass cover 20 side and is performed in the assembly plant by using the backlight for inspection.

Fig. 5 is a schematic plan view of a liquid crystal display panel to which the present invention is applied. In fig. 5, the TFT substrate 100 and the counter substrate 200 are bonded to each other by a sealing material 150, and a display region 90 is formed in a region surrounded by the sealing material 150. The peripheral region including the seal 150 becomes the rim region 95. In the TFT substrate 100, scanning lines 91 extend in the lateral direction (x direction) and are arranged in the longitudinal direction (y direction), video signal lines 92 extend in the longitudinal direction and are arranged in the lateral direction, and pixels 93 are formed in regions surrounded by the scanning lines 91 and the video signal lines 92.

The TFT substrate 100 is formed larger than the counter substrate 200, and a portion where the TFT substrate 100 and the counter substrate 200 do not overlap becomes the terminal region 160. A flexible wiring board 170 for supplying power and signals to the liquid crystal display device is connected to the terminal region 160.

Fig. 6 is a plan view of the pixel 93 in the TFT substrate 100. Fig. 6 shows a pixel 93 in an IPS liquid crystal display device. In fig. 6, the scanning lines 91 extend in the lateral direction (x direction) and are aligned in the longitudinal direction (y direction). The video signal line 92 extends in the vertical direction, but extends at a portion where the comb-shaped pixel electrode 112 is formed, with an inclination of θ or- θ with respect to the initial alignment direction of the liquid crystal, that is, the y-direction. The pixel electrode 112 is formed in a region surrounded by the scanning line 91 and the video signal line 92. The pixel electrode 112 is formed of a comb-shaped electrode portion and a contact portion having a through hole 130. A common electrode 110 is formed in a planar shape on the lower layer side of the pixel electrode 112 with a capacitor insulating film interposed therebetween.

The pixel electrode 112 is formed so as to be inclined by θ with respect to the y direction, similarly to the video signal line 92. The orientation direction 30 of the orientation film is the y-direction. Accordingly, when a signal voltage is applied to the pixel electrode 112, the rotation direction of the liquid crystal is defined, and generation of a domain (domain) is prevented. The initial alignment direction 30 of the alignment film formed on the counter substrate is also the y direction.

A semiconductor layer 103 is formed below the video signal lines 92 and the scanning lines 91 with an insulating film interposed therebetween. The TFT is formed when the semiconductor layer 103 passes under the scanning line 91. In this case, the scanning line 91 functions as a gate. Thus, in fig. 6, two TFTs are formed.

In fig. 6, the semiconductor layer 103 is connected to the video signal line 92 at a via 120 and to the source 107 at a via 125. The source electrode 107 is connected to the pixel electrode 112 at the via hole 130.

Fig. 7 is a sectional view a-a of fig. 6. The TFT in fig. 7 is a so-called top gate TFT, and LTPS (Low Temperature polysilicon) is used as a semiconductor used. In fig. 7, a 1 st base film 101 composed of SiN and a SiO film composed of SiO are formed over a glass substrate 100 by CVD (Chemical Vapor Deposition)₂And a 2 nd base film 102. The 1 st base film 101 and the 2 nd base film 102 function to prevent impurities from the glass substrate 100 from contaminating the semiconductor layer 103.

A semiconductor layer 103 is formed over the 2 nd base film 102. The semiconductor layer 103 is obtained by forming an a-Si film over the 2 nd base film 102 by CVD and converting the a-Si film into a polysilicon film (poly-Si film) by laser annealing. The polysilicon film is patterned by photolithography.

A gate insulating film 104 is formed over the semiconductor film 103. The gate insulating film 104 is SiO based on TEOS (tetraethoxysilane)₂And (3) a membrane. The film is also formed by CVD. A gate electrode 105 is formed over the film. The gate electrode 105 doubles as the scanning line 91 shown in fig. 6. The semiconductor layer passes under the scanning line 91 twice, and thus, in fig. 7, two gate electrodes 105 are arranged. The gate electrode 105 is formed of, for example, a MoW film.

The gate electrode 105 is patterned by photolithography, and in the patterning, impurities such as phosphorus or boron are doped into a polysilicon layer (poly-Si layer) by ion implantation to form a source or a drain in the polysilicon layer. In addition, an LDD (Lightly Doped Drain) layer is formed between the channel layer and the source or Drain of the polysilicon layer by using a photoresist used in patterning the gate electrode 105. This is to prevent the electric field intensity from locally becoming large.

Thereafter, the gate 105 is covered with SiO₂Or SiO₂The 1 st interlayer insulating film 106 is formed as a laminated film with SiN. The 1 st interlayer insulating film 106 is used to insulate the gate electrode 105 from the source electrode 107. A through hole 125 for connecting the semiconductor layer 103 and the source 107 is formed in the 1 st interlayer insulating film 106 and the gate insulating film 104. Photolithography for forming the via hole 125 in the 1 st interlayer insulating film 106 and the gate insulating film 104 is performed at the same time.

Video signal lines are formed on the 1 st interlayer insulating film 106. The video signal line is connected to the semiconductor layer 103 at the via hole 120 shown in fig. 6. That is, two TFTs are formed between the via 120 and the via 125. On the 1 st interlayer insulating film 106, a source 107 is formed in the same layer as the video signal line 92. The source electrode 107 is connected to the pixel electrode 112 via a via hole 130. The video signal line 92 and the source 107 are formed of, for example, a laminated film of Al, Ti, or the like, MoW, or the like.

The inorganic passivation film 108 is formed of SiN or the like so as to cover the video signal line 92 and the source electrode 107, and protects the entire TFT. The inorganic passivation film 108 is formed by CVD in the same manner as the 1 st base film 101. An organic passivation film 109 is formed to cover the inorganic passivation film 108. The organic passivation film 109 is formed of a photosensitive acrylic resin. The organic passivation film 109 can be formed of a silicone resin, an epoxy resin, a polyimide resin, or the like, in addition to an acrylic resin. The organic passivation film 109 has a function as a planarization film, and is thus formed thick. The thickness of the organic passivation film 109 is 1 μm to 4 μm, but is often about 2 μm.

In order to establish electrical continuity between the pixel electrode 112 and the source electrode 107, a through hole 130 is formed in the inorganic passivation film 108 and the organic passivation film 109. A photosensitive resin is used for the organic passivation film 109. After a photosensitive resin is applied, when the resin is exposed, only the portion irradiated with light is dissolved in a specific developer. That is, by using a photosensitive resin, the formation of a photoresist can be omitted. After the through-hole 130 is formed in the organic passivation film 109, the organic passivation film is fired at about 230 ℃, and the organic passivation film 109 is completed.

Then, ITO (Indium Tin Oxide) to be the common electrode 110 is formed by sputtering, and then, patterning is performed so as to remove the ITO from the via hole 130 and the periphery thereof. The common electrode 110 can be formed in a planar shape in common to each pixel. After that, SiN to be the 2 nd interlayer insulating film 111 is formed on the entire surface by CVD. After that, inside the via hole 130, a via hole for conduction of the source electrode 107 and the pixel electrode 112 is formed in the 2 nd interlayer insulating film 111 and the inorganic passivation film 108.

Then, ITO is formed by sputtering and patterned to form the pixel electrode 112. The planar shape of the pixel electrode 112 is shown in fig. 6. An alignment film material is applied on the pixel electrode 112 by flexography, inkjet, or the like, and fired to form an alignment film 113. In the alignment treatment of the alignment film 113, photo-alignment based on polarized ultraviolet rays may be used in addition to the rubbing method. The orientation of the orientation axis obtained by the orientation processing is shown in fig. 6.

When a voltage is applied between the pixel electrode 112 and the common electrode 110, electric flux lines as shown in fig. 7 are generated. The liquid crystal molecules 301 are rotated by the electric field, and an image is formed by controlling the amount of light passing through the liquid crystal layer 300 on a pixel-by-pixel basis.

In fig. 7, the counter substrate 200 is disposed with a liquid crystal layer 300 interposed therebetween. A color filter 201 is formed inside the counter substrate 200. The color filter 201 forms a color image by forming red, green, and blue color filters for each pixel. A black matrix 202 is formed between the color filters 201 and the color filters 201 to improve the contrast of an image. The black matrix 202 also functions as a light-shielding film for the TFTs, and prevents a flow of light to the TFTs.

An overcoat film (overcoat film)203 is formed to cover the color filters 201 and the black matrix 202. Since the surfaces of the color filter 201 and the black matrix 202 are uneven, the surfaces are flattened by the cover film 203. An alignment film 204 for determining the initial alignment of the liquid crystal is formed on the cover film. The alignment treatment of the alignment film 204 is performed by a rubbing method or a photo-alignment method, as in the case of the alignment film 113 on the TFT substrate 100 side. The orientation axis 30 is in the same direction as the orientation axis 30 on the TFT substrate 100 side, and is the direction of the arrow in fig. 6.

Fig. 8 is a schematic cross-sectional view showing the structure of the present invention. The structure of fig. 8 is basically the same as that of fig. 1, but in fig. 8, the inspection device of the present invention is disposed above the liquid crystal module, and the absorption axis direction of the glass cover side polarizing plate 51 is different in the optical axis structure shown in fig. 3. In fig. 8, the TFT substrate 100 to which the lower polarizer 10 is attached and the counter substrate 200 to which the upper polarizer 11 is attached are attached by a sealing material, and the retardation film 12 is attached on the upper polarizer 11. A backlight 500 is disposed on the rear surface of the liquid crystal display panel 400. The liquid crystal module is configured from the backlight 500 to the retardation film 12.

In fig. 8, an inspection device 60 according to the present invention is disposed above the liquid crystal module. The inspection device 60 has a retardation film 52 for inspection bonded to a glass substrate 50, and an inspection polarizing plate 51 bonded to the retardation film 52 for inspection. The inspection apparatus of fig. 8 is made of the same material but has a different optical axis structure than the filter structures 21, 22 attached to the cover glass 10 of fig. 1. In addition, the reason why the glass cover sheet 10 is positioned at the upper side in fig. 1 and the glass substrate 50 is positioned at the lower side in fig. 8 is different in that the handling is easier when the glass substrate 50 is positioned at the lower side in the inspection process.

In both fig. 8 and fig. 1, the retardation films 52 and 22 are disposed on the liquid crystal module side, and the polarizing plates 51 and 21 are disposed on the side away from the liquid crystal module side.

In fig. 8, the directions of the alignment axes 30 of the alignment films of the TFT substrate 100 and the counter substrate 200, the slow axis 32 of the retardation film 12, and the absorption axis 31 of the polarizing plate 11 are also basically the same as those described in fig. 2. However, the structure of the inspection retardation film 52 in fig. 8 is a structure unique to the present invention.

Fig. 9 is an exploded perspective view illustrating a retardation film 52 and a polarizing plate 51 of the present invention partially overlapped with each other. In fig. 9, the absorption axis 31 of the polarizing plate 51 is the x direction. The retardation film 52 is formed by sticking films having rectangular shapes different from each other every 0.5 degrees on the slow axis 32 side by side. The numerical values corresponding to the respective rectangular retardation films in fig. 9 indicate deviations from 45 degrees with respect to the x direction, which is the absorption axis 31 of the polarizing plate 51. That is, 0 degree means 45 degrees with respect to the x direction, and +1 degree means 46 degrees with respect to the x direction.

In fig. 9, the retardation film 52 is formed of a plurality of rectangular films, and therefore the retardation film 52 in fig. 9 can also be referred to as a retardation film group formed of a plurality of rectangular films. The slow axes of the rectangular retardation films adjacent to each other are different by 0.5 °. The inspection device 60 allows the polarizing plate 51 and the retardation film 52 to be accurately controlled in terms of both component accuracy and bonding accuracy.

Fig. 10 is a plan view showing a visual evaluation state in the case where the inspection apparatus having the configuration of fig. 9 is used in the inspection apparatus of fig. 8. The liquid crystal module in fig. 8 is normally black, and therefore, the smaller the luminance, the better, that is, the darker the luminance. In fig. 10, the 0.5-degree rectangular area is darkest.

When the intersection angle between the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 in the liquid crystal module and the intersection angle between the absorption axis 31 of the polarizing plate 51 and the slow axis 32 of the retardation film 52 in the inspection apparatus coincide with each other, light is blocked to the maximum extent, that is, black is formed. Accordingly, the state of fig. 10 shows that the offset of the crossing angle between the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 in the liquid crystal module is +0.5 degrees.

If the crossing angle between the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 in the liquid crystal module is 2 °, the 2-degree portion becomes blackest in fig. 10. And becomes brighter as it is farther from 2 °. That is, the degree of depth of black becomes insufficient. The tolerance for the crossing angle can be up to a few degrees determined by the panel manufacturer and assembler.

Fig. 11A is a sectional view showing the structure of the inspection apparatus of the present invention. Fig. 11B is a plan view of the inspection apparatus of the present invention, and mainly shows the structure of the retardation film 52. In fig. 11A, the substrate 50 is a glass substrate, and the thickness ts is, for example, 0.5mm to 0.7mm, and may be glass having a standard thickness that can be commercially supplied. A retardation film 52 for inspection is bonded on the glass substrate 50. The thickness tr of the inspection retardation film 52 is, for example, 20 μm to 70 μm. In fig. 11A, a polarizing plate 51 is attached to a retardation film 52. The thickness tp of the polarizing plate 51 is, for example, 100 μm to 130 μm.

Fig. 11B is a plan view of the inspection apparatus, showing the structure of the retardation film 52 attached to the glass substrate 50. In fig. 11B, the area to which the rectangular retardation film is attached is xx in the x direction and yy in the y direction, and is slightly larger than the display area of the display device to be inspected. The width w of each rectangle is 0.5mm, for example, which is enough to facilitate evaluation of brightness by visual observation.

In fig. 11B, the numerals shown on the right side of the rectangles indicate the offset, which is the angle at which the slow axis 32 of the retardation film 52 is displaced from 45 degrees. That is, for example, 0 ° indicates that the slow axis of the rectangular retardation film is 45 degrees, 1 ° indicates that the slow axis of the rectangular retardation film is 46 degrees, and-1 ° indicates that the slow axis of the rectangular retardation film is 44 degrees.

In fig. 8, if the slow axis of the retardation film in the liquid crystal module is 44 ° with respect to the absorption axis of the polarizing plate, the portion of the retardation film having a rectangular shape of-1 ° in fig. 11B becomes dark. In fig. 11B, the rectangular retardation films are formed so that the slow axes thereof are different in 0.5 ° units. That is, the deviation from the normal angle between the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 in the liquid crystal module can be measured in units of 0.5 °.

In the present invention, it is assumed that the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 are the same in each liquid crystal display device. This is because, although both the polarizing plate 11 and the retardation film 12 are cut out from a large mother film (heat film), the area of each liquid crystal display device is smaller than that of the mother film, and therefore, the same is not true in each liquid crystal display device.

The rectangular retardation film in fig. 11B is provided with a retardation film of-6 ° to +6 °. In an actual product, the deviation from the normal angle between the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 in the liquid crystal module does not change to-6 ° or +6 °, but in fig. 11B, by setting the range of the slow axis 32 of the rectangular retardation film 52 to be large, it is easy to visually and easily determine which part of the rectangular retardation film is the darkest.

Fig. 12 is a cross-sectional view showing another example of the inspection apparatus of the present invention. That is, there is a case where measurement is performed in the same arrangement as an actual product depending on the product. That is, there is a case where the polarizing plate 51 and the retardation film 52 are disposed below the glass substrate 50 with the glass substrate 50 positioned above. In this case, the polarizing plate 51 is first placed in contact with the glass substrate 50, and the retardation film 52 is bonded to the polarizing plate 51. That is, the polarizing plate 21 and the retardation film 22 are arranged in the same manner as those of the cover glass 20 in the set shown in fig. 1.

In fig. 12, the arrangement of the retardation film 52 is also the same as that in fig. 11B. In the case of the glass substrate 50, either the structure of fig. 11A or the structure of fig. 12 can be used. That is, the reason for this is that the glass has no birefringence characteristics. Fig. 11B and 12 are common in that the retardation film 52 is disposed at a position closer to the liquid crystal module to be inspected than the polarizing plate 51.

Fig. 13 is a cross-sectional view showing still another example of the inspection apparatus of the present invention. The structure of fig. 11A and 12 uses a glass substrate 50 as a substrate, but in fig. 13, a transparent plastic substrate 70 is used as the substrate. This is because the plastic substrate 70 is light and has high resistance to cracking and the like, and thus is easy to handle. However, in general, plastics have optical anisotropy. Therefore, if a plastic substrate is present between the liquid crystal module and the inspection retardation film 52, the polarization state of circularly polarized light emitted from the liquid crystal module changes. That is, the optical characteristics vary in products and inspections.

Therefore, when the plastic substrate 70 is used, as shown in fig. 13, the plastic substrate 70 is positioned on the upper side, the inspection polarizing plate 71 is disposed on the lower surface of the plastic substrate, and the retardation film 72 as shown in fig. 11B is disposed below the inspection polarizing plate 71. That is, the retardation film 12 on the liquid crystal module side directly faces the inspection retardation film 72.

Even in the case of the inspection apparatus using the plastic substrate 70 as shown in fig. 13, the inspection method is the same as the inspection principle described with reference to fig. 8 to 10. The inspection retardation film 72 used may have the same structure as that of fig. 11B.

[ example 2 ]

In embodiment 1, an example in which the present invention is applied to a liquid crystal display device is described. The utility model discloses also can be applicable to organic EL display device. The organic EL display device is self-luminous, and therefore, does not need a backlight. Light emitted from the organic EL display device is not polarized light, but a polarizing plate is attached to the display surface side in order to prevent reflection of external light.

In order to more reliably prevent reflection of external light, the following operations are performed in an assembly plant, as in the case of a liquid crystal display device: a polarizing plate for antireflection and a retardation film for antireflection are disposed on the glass cover side, and a polarizing plate and a retardation film are disposed on the display surface side of the organic EL display device.

Fig. 14 is a cross-sectional view of the display device having such a structure for the organic EL display device. The basic configuration of fig. 14 is the same as that of the liquid crystal display device of fig. 1. Fig. 14 differs from fig. 1 in that there is no backlight and no lower polarizer. The reason for this is that the organic EL display device is self-luminous. Further, the polarizing plate 601 present on the surface of the organic EL display device 600 is not for polarization detection, but for reflection prevention.

In fig. 14, a polarizing plate 601 is attached to an organic EL display device 600, and a retardation film 602 is attached to the polarizing plate 601. The cover glass 20, the polarizing plate 21 for a filter, and the retardation film 22 for a filter, which are disposed opposite to the retardation film 602 of the organic EL display device and prepared on the assembly plant side, are the same as those described in fig. 1.

Fig. 15 is a schematic cross-sectional view showing an inspection process in a case where the present invention is applied to an organic EL display device 600. Fig. 15 is different from fig. 8 in that fig. 8 is a liquid crystal module, but fig. 15 is a structure in which a polarizing plate 601 and a retardation film 602 are attached to an organic EL display device 600. The other structure of fig. 15 is the same as fig. 8. Specifically, in fig. 15, neither a backlight nor a lower polarizer is present. However, the inspection apparatus 55 and the inspection method are the same as those described with reference to fig. 8 to 10. The specific structure of the retardation film 52 is the same as that described with reference to fig. 11B.

As described above, the inspection device of the present invention has a simple structure and can perform an inspection quickly. Therefore, the total number of inspection can be performed, and the quality of the product can be finely dealt with.

[ example 3 ]

In examples 1 and 2, the deviation of the intersection angle between the slow axis of the retardation film on the liquid crystal module side or the organic EL display device side and the absorption axis of the polarizing plate from the reference value was evaluated. On the other hand, on the assembly plant side, it is also necessary to suppress the deviation of the absorption axis 31 of the polarizing plate and the slow axis 32 of the retardation film from the reference angle, which are adhered to the cover glass 20 side.

When the present invention described in embodiment 1 is used, the deviation from the reference angle between the absorption axis 31 of the polarizing plate attached to the cover glass 20 side and the slow axis 32 of the retardation film can be easily measured even in the assembly plant side. Fig. 16 is a schematic cross-sectional view showing a structure in a case where the present invention is used on the assembly plant side. The structure of 16 is basically the same as the inspection method for the liquid crystal module shown in fig. 8. In fig. 16, a cover glass 20, a polarizing plate 21 for a filter, and a retardation film 22 for a filter, which are used in a process on the assembly plant side, are disposed instead of the liquid crystal module.

In fig. 16, a backlight 700 for inspection is disposed on the back surface of the cover glass 20. The backlight 500 in fig. 8 may be the backlight 500 incorporated in the liquid crystal module, but in fig. 16, the backlight 700 for inspection needs to be prepared. The backlight 700 may be configured according to the backlight 500 mounted on the liquid crystal module.

In fig. 16, a filter polarizing plate 21 is attached to a cover glass 20, and a filter retardation film 22 is attached to the filter polarizing plate 21. The cover glass 20, the polarizing plate 21 for optical filter, and the phase difference film 22 for optical filter are components actually used in products. However, in fig. 16, the order of the cover glass 20, the filter polarizing plate 21, and the filter retardation film 22 shown in fig. 1 is reversed for the purpose of inspection. That is, it becomes an inversion of the structure shown in fig. 1.

The inspection device 55 is disposed so as to face the retardation film 22 for optical filter. The inspection device 55 is a device in which an inspection retardation film 52 is attached to a glass substrate 50, and an inspection polarizing plate 51 is attached to the inspection retardation film 52. The inspection apparatus 55 is similar to the inspection apparatus described in fig. 8 of example 1.

The principle of measuring the deviation of the absorption axis 31 of the filter polarizing plate 21 and the slow axis 32 of the filter phase difference film 22 from 45 °, that is, the offset in fig. 16 is the same as that described in fig. 8 to 10 in example 1. The structure of the inspection retardation film 52 is also the same as that described with reference to fig. 11B. The configuration of the inspection apparatus 55 can be not only the configuration described with reference to fig. 11A, but also the configurations described with reference to fig. 12 and 13.

In this way, even in an assembly plant, the inspection can be performed quickly by using the inspection apparatus of the present invention having a simple structure. Thus, it is possible to make it possible to finely cope with the quality of the product.

In the above description, the angle formed by the absorption axis 31 of the polarizing plate and the slow axis 32 of the retardation film is set to 45 °, but in some cases, when it is desired to set the light emitted from the liquid crystal module or the like to elliptically polarized light, the angle formed by the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 is set to an angle other than 45 °. In this case, the present invention can be applied.

Fig. 17 shows the axial structure of the polarizing plate 51 and the retardation film 52 on the glass cover side for inspecting the polarizing plate 11 and the retardation film 12 at an arbitrary angle in the liquid crystal module. As shown in fig. 17, when the absorption axis 31 of the polarizing plate 51 is orthogonal to the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 52 is orthogonal to the slow axis 32 of the retardation film 12, the transmitted light becomes the darkest regardless of the angle formed by the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 (fig. 17 shows a case where the transmitted light becomes darkest even when two retardation films 12 orthogonal to the slow axis 32 are rotated). Therefore, even when the angle formed by the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 is an angle other than 45 °, the deviation, that is, the offset of the angle formed by the absorption axis 31 of the polarizing plate 11 and the slow axis 32 of the retardation film 12 from the design value can be checked by the brightness of the transmitted light.

Claims (11)

1. An inspection apparatus for a display device, wherein a retardation film group comprising a plurality of rectangular retardation films is disposed on a transparent substrate, and a polarizing plate is disposed on the retardation film group,

the polarizing plate has an absorption axis and,

the plurality of rectangular retardation films each have a slow axis,

the slow axis is at a prescribed angle with respect to the absorption axis,

the predetermined angle monotonically increases or decreases from the predetermined angle of the rectangular retardation film existing at the 1 st end of the retardation film group to the predetermined angle of the rectangular retardation film existing at the 2 nd end opposite to the 1 st end of the retardation film group.

2. The inspection device of claim 1,

the predetermined angle of at least one of the plurality of rectangular retardation films is 45 °.

3. The inspection apparatus of claim 2,

the rectangular retardation film having the predetermined angle of 45 ° is present at the center of the retardation film group.

4. The inspection device of claim 1,

an angle formed by the slow axes of adjacent retardation films among the plurality of rectangular retardation films is a 1 st angle,

the 1 st angle is 0.5 °.

5. The inspection device of claim 1,

the transparent substrate is a glass substrate.

6. An inspection apparatus for a display device, wherein a polarizing plate is disposed on a transparent substrate, and a retardation film group comprising a plurality of rectangular retardation films is disposed on the polarizing plate,

the polarizing plate has an absorption axis and,

each of the plurality of rectangular retardation films has a slow axis forming a predetermined angle with the absorption axis of the polarizing plate,

the predetermined angle is different for each of the plurality of rectangular retardation films,

the predetermined angle monotonically increases or monotonically decreases from the predetermined angle of the rectangular retardation film existing at one end of the retardation film group to the predetermined angle of the rectangular retardation film existing at the other end of the retardation film group.

7. The inspection device of claim 6,

the predetermined angle of at least one of the plurality of rectangular retardation films is 45 °.

8. The inspection device of claim 7,

the rectangular retardation film having the predetermined angle of 45 ° is present at the center of the retardation film group.

9. The inspection device of claim 6,

an angle formed by the slow axes of adjacent retardation films among the plurality of rectangular retardation films is a 1 st angle,

the 1 st angle is 0.5 °.

10. The inspection device of claim 6,

the transparent substrate is a glass substrate.

11. The inspection device of claim 6,

the transparent substrate is a plastic substrate.

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