CN110045535A - Liquid crystal disply device and its preparation method - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method of manufacturing the same. An object of the present invention is to realize a flexible liquid crystal display device. The solution of the present invention is a liquid crystal display device, which is a liquid crystal display device in which a liquid crystal (300) is sandwiched between a display region and a counter substrate (200) formed of resin, and the display region includes an inorganic insulating material. A plurality of pixels with TFTs are formed on the TFT wiring layer (60) of the film, and the liquid crystal display device is characterized in that a lower polarizer (401) is adhered on the TFT wiring layer (60) to sandwich the The liquid crystal (300) is removed, and an upper polarizer (402) is adhered to the opposite substrate (200).

Description

Liquid crystal display device and method of manufacturing the same

technical field

The present invention relates to a display device, in particular to a flexible liquid crystal display device.

Background technique

In a liquid crystal display device, pixels having pixel electrodes, thin film transistors (TFTs), and the like are formed in a matrix, and an image is formed by controlling the transmittance of liquid crystal for each pixel. Since liquid crystal display devices are lightweight and capable of displaying images with high definition, their use is widespread in various fields. In recent years, also in liquid crystal display devices, there is a field in which the display device is required to be able to bend flexibly.

In Patent Document 1, in order to realize a flexible liquid crystal display device, a TFT is formed on glass and transferred to a transparent resin substrate to realize a flexible liquid crystal display device.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2015-102683

SUMMARY OF THE INVENTION

The problem to be solved by the invention

In a liquid crystal display device, a TFT is used as a switching transistor in a pixel, but when a TFT is formed using polysilicon (poly-Si), it is necessary to perform annealing at 400° C. or higher. When a TFT is formed using an oxide semiconductor, it can be formed by annealing at about 300°C, but it is necessary to anneal at about 350°C in order to stabilize the characteristics. Even if the manufacturing apparatus is set to such a temperature, it is still higher than 350°C locally.

In order to realize a flexible display device, it is necessary to form a TFT substrate using a resin such as polyimide. There are also various materials for polyimide, but the heat resistance temperature of transparent polyimide is about 350°C. Therefore, it is impossible to form a TFT using polysilicon on a transparent polyimide, and it is difficult to realize a TFT using an oxide semiconductor with high reliability.

An object of the present invention is to realize a flexible display device capable of forming a TFT by a high temperature process.

means of solving problems

The present invention is an invention for overcoming the above-mentioned problems, and the main specific means are as follows.

(1) A liquid crystal display device in which a liquid crystal is sandwiched between a display region in which a plurality of pixels having TFTs are formed on an inorganic insulating film and a counter substrate formed of resin , the liquid crystal display device is characterized in that a lower polarizer is adhered on the inorganic insulating film.

(2) A method of manufacturing a liquid crystal display device, wherein a polyimide is formed on a first glass substrate, an inorganic insulating film including a plurality of layers is formed on the polyimide, and an inorganic insulating film is formed on the inorganic insulating film A TFT-containing layer is formed, and a counter substrate is arranged to face the TFT-containing layer with a liquid crystal sandwiched therebetween, the counter substrate is formed of a transparent resin formed on a second glass substrate, and then the first glass is removed The substrate and the polyimide, the lower polarizer is attached to the inorganic insulating film, and then the second glass substrate is removed.

(3) A method of manufacturing a liquid crystal display device, wherein an amorphous silicon (a-Si) film is formed on a first glass substrate, an inorganic insulating film including a plurality of layers is formed on the a-Si film, and an inorganic insulating film is formed on the a-Si film. A TFT-containing layer is formed on the inorganic insulating film, and a counter substrate is arranged to face the TFT-containing layer with a liquid crystal sandwiched therebetween, and the counter substrate is made of a transparent resin formed on a second glass substrate, and then removed For the first glass substrate, the lower polarizer is attached to the inorganic insulating film or the a-Si film, and then the second glass substrate is removed.

Description of drawings

1 is a plan view of a liquid crystal display device.

[ Fig. 2 ] is a cross-sectional view taken along line A-A of Fig. 1 .

3 is a plan view of a pixel portion of a liquid crystal display device.

4 is a cross-sectional view of a pixel portion of a liquid crystal display device.

[ Fig. 5] Fig. 5 is a plan view of the mother substrate.

6 is a cross-sectional view in which colored polyimide is formed on the first glass substrate.

[ Fig. 7] Fig. 7 is a cross-sectional view of a TFT wiring layer formed on colored polyimide.

8 is a cross-sectional view showing a state after an alignment film is formed.

9 is a cross-sectional view of dropping a liquid crystal on an alignment film.

10 is a cross-sectional view of a state in which a counter substrate with a second glass substrate is bonded together.

11 is a cross-sectional view of a state in which FIG. 10 is turned upside down.

12 is a cross-sectional view showing a state in which the first glass substrate is removed.

13 is a cross-sectional view showing a state in which colored polyimide is removed by plasma ashing.

14 is a cross-sectional view showing an example of a plasma ashing process.

15 is a cross-sectional view showing another example of the plasma ashing process.

16 is a cross-sectional view showing a state after removing the colored polyimide.

[ Fig. 17] Fig. 17 is a cross-sectional view showing a state in which a lower polarizer is attached to a TFT wiring layer.

18 is a cross-sectional view of a state in which FIG. 17 is turned upside down.

19 is a cross-sectional view showing a state in which the second glass substrate is removed.

[ Fig. 20] Fig. 20 is a cross-sectional view of a state in which the upper polarizing plate is attached to a counter substrate.

21 is a cross-sectional view showing a state in which an a-Si film is formed on a first glass substrate in Example 2. FIG.

22 is a cross-sectional view of a state in which a TFT wiring layer is formed on the a-Si film.

23 is a cross-sectional view showing a state in which the first glass substrate and the a-Si film are removed.

24 is a plan view illustrating a liquid crystal display device of Example 3. FIG.

[ Fig. 25] Fig. 25 is a cross-sectional view of a state in which the terminal region in Fig. 24 is bent.

26 is a plan view showing a first aspect of Example 3. [ FIG.

[ Fig. 27 ] A cross-sectional view of a state in which the terminal region in Fig. 26 is bent.

28 is a plan view showing a second aspect of the third embodiment.

29 is a cross-sectional view showing an intermediate step of the second aspect of Example 3. FIG.

[ Fig. 30 ] A cross-sectional view of a state in which the terminal region in Fig. 28 is bent.

31 is a plan view showing a third aspect of the third embodiment.

[ Fig. 32 ] A detailed cross-sectional view of the terminal region of Fig. 31 .

[ Fig. 33] Fig. 33 is a cross-sectional view of a state in which the terminal region in Fig. 31 is bent.

34 is a cross-sectional view showing a fourth aspect of the third embodiment.

FIG. 35 is a plan view of Example 4. FIG.

[ Fig. 36 ] A cross-sectional view taken along the line B-B of Fig. 35 .

37 is a rear view of Example 4. [ FIG.

Description of reference numerals

10...liquid crystal cell, 11...scanning line, 12...image signal line, 13...pixel, 15...lead-out line, 16...insulating layer, 30...display area, 40...terminal area, 41...driver IC,

42...Bumps, 45...Terminal wiring, 46...Anisotropic conductive film, 50...Sealing material,

60...TFT wiring layer, 70...protective resin, 90...glass substrate, 95...a-Si, 100...colored polyimide, 101...first base film, 102...second base film, 103...semiconductor layer, 104 ...gate insulating film, 105...gate electrode, 106...interlayer insulating film, 107...contact electrode, 108...inorganic passivation film, 109...organic passivation film, 110...common electrode, 111...capacitive insulating film, 112... Pixel electrode, 113...alignment film, 130...through hole, 131...through hole, 132...through hole, 200...counter substrate, 201...color filter, 202...black matrix,

203...overcoat film, 204...alignment film, 200...opposing substrate, 210...upper glass substrate, 220...color filter layer, 300...liquid crystal layer, 301...liquid crystal molecules, 401...lower polarizer, 402...upper Polarizer, 500...flexible wiring substrate, 600...mother board, 700...plasma, 701...lower electrode, 702...upper electrode, 710...jig, 711...motor, 720...mask, 4021...adhesive material, 4022... Adhesive material, AL...Orientation direction, D...Drain, S...Source electrode

Detailed ways

Hereinafter, the present invention will be described in detail using examples.

[Example 1]

FIG. 1 is a top view of a liquid crystal display device to which the present invention is applied. FIG. 1 is an example of a liquid crystal display device used in a mobile phone, a tablet computer, or the like. In FIG. 1 , the TFT wiring layer 60 and the counter substrate 200 on which the black matrix and the like are formed are bonded via the sealing material 50 , and liquid crystal is sandwiched between the TFT wiring layer 60 and the counter substrate 200 . Pixels including TFTs, pixel electrodes, and the like are arranged in a matrix.

The opposing substrate 200 is formed of transparent resin such as polyimide. The upper polarizer 402 is overlapped with the opposing substrate 200 . The present invention is characterized in that there is no so-called TFT substrate, and the TFT wiring layer 60 is directly disposed on the lower polarizer 401 . Here, the TFT wiring layer 60 is a concept including various insulating films represented by a base film, TFTs, wirings, organic passivation films, alignment films, and the like.

In the TFT wiring layer 60 in the display area 30, the scan lines 11 extend in the lateral direction (x direction) and are arranged in the longitudinal direction (y direction). In addition, the video signal lines 12 extend in the vertical direction and are arranged in the horizontal direction. Pixels 13 are formed in regions surrounded by the scanning lines 11 and the video signal lines 12 .

The TFT wiring layer 60 extends from the display region 30 to the terminal region 40 . The TFT wiring layer 60 is a thin layer, and although it is flexible, it is mechanically weak. Therefore, the lower polarizer 401 extends to the terminal region 40 and is also mechanically reinforced. The terminal area 40 has the driver IC 41 mounted thereon, and is connected to the flexible wiring board 500 .

FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1 . In FIG. 2 , the TFT wiring layer 60 is arranged on the adhesive material 4011 of the lower polarizer 401 . The lower polarizer 401 , the adhesive material 4011 , and the TFT wiring layer 60 extend not only in the display area but also in the terminal area 40 . The opposing substrate 200 and the color filter layer 220 formed on the opposing substrate 200 are arranged in a portion corresponding to the display area 30 . The color filter layer 220 is a concept including a color filter, a black matrix, an overcoat film, an alignment film, and the like. The opposing substrate 200 is formed of transparent resin.

The liquid crystal layer 300 is sandwiched between the TFT wiring layer 60 and the color filter layer 220 . The sealing material 50 adheres the TFT wiring layer 60 and the color filter layer 220 and seals the liquid crystal 300 . The upper polarizer 402 is bonded to the opposing substrate via the bonding material 4021 . The liquid crystal display device has a backlight on the back, but is omitted in FIG. 2 .

FIG. 3 is a plan view of the display area 30 of the liquid crystal display device in the present invention. FIG. 3 is an example of a liquid crystal display device of an IPS (InPlane Switching) method. In FIG. 3 , pixel electrodes 112 are formed in regions surrounded by the scanning lines 11 and the video signal lines 12 . In FIG. 3 , the pixel electrode 112 has two slits and is formed of three comb-teeth electrodes. Each comb-teeth electrode is curved near the center. This is to make the field angle characteristics more uniform.

The alignment axis AL of the alignment film that defines the initial alignment direction of the liquid crystal molecules is the longitudinal direction (y direction). The comb-teeth electrodes are inclined only by an angle θ with respect to the y-direction. This is to define the rotation direction of the liquid crystal molecules when a voltage is applied between the pixel electrode 112 and the common electrode 110 .

The angle of θ is 5 degrees to 15 degrees. By bending the pixel electrode 112, the rotation direction of the liquid crystal is made different on the upper side and the lower side in the y-direction of the pixel, thereby making the viewing angle more uniform. However, the rotation direction of the liquid crystal molecules is uncertain at the curved portion of the comb-shaped electrode, and a so-called domain boundary occurs. In the portion of the region boundary, the transmittance decreases.

In FIG. 3 , the semiconductor layer 103 is connected to the image signal line at the through hole 131 , passes under the scan line 11 twice, and is connected to the contact electrode 107 at the through hole 132 . Since the TFT is formed at a position where the semiconductor layer 103 passes under the scanning line 11 , in FIG. 2 , two TFTs are formed in series. Alternatively, a double-gate TFT may be formed.

The contact electrode 107 is connected to the pixel electrode 112 at the through hole 130 formed in the organic passivation film. On the organic passivation film, the common electrode 110 is formed in a planar shape (except for the portion of the through hole 130). The pixel electrode 112 is formed on the capacitive insulating film formed to cover the common electrode 110 .

FIG. 4 is a cross-sectional view of a display area corresponding to FIG. 3 . As shown in FIG. 4 , in the present invention, a TFT substrate is not used. As will be described later, in the initial stage, the TFT wiring layer in which the TFT and the wiring layer are formed is formed on the glass substrate and the colored polyimide, and then the glass substrate and the colored polyimide are removed, and the glass substrate is replaced with the colored polyimide. The lower polarizer is attached to the TFT wiring layer.

A flexible display device using a transparent resin substrate cannot form a TFT using poly-Si due to the limitation of the heat resistance temperature of the resin substrate. In the present invention, colored polyimide is used as a TFT substrate in the manufacturing process, and since the heat resistance temperature of colored polyimide is higher than that of transparent polyimide, a TFT can be formed using poly-Si.

In addition, an oxide semiconductor can be used in the present invention. The reliability of oxide semiconductors is improved by annealing at high temperatures. With the structure of the present invention, even when an oxide semiconductor is used, annealing can be performed at a high temperature, so that a highly reliable TFT can be used. In addition, in the present invention, a TFT using a-Si (amorphous silicon) can also be produced.

The TFT in FIG. 4 is a so-called top-gate TFT, and poly-Si is used as the semiconductor used. On the other hand, when an a-Si semiconductor is used, a so-called bottom-gate TFT is often used. In addition, an oxide semiconductor can be used in either case. In the following description, the case where a top-gate type TFT is used as an example will be described, but the present invention is also applicable to a case where a bottom-gate type TFT is used.

In FIG. 4 , the first base film 101 is formed of, for example, silicon nitride (represented by SiN hereinafter), and the second base film 102 is formed of, for example, silicon oxide (represented by SiO hereinafter). The thickness of the first base film is, for example, 100 nm, and the thickness of the second base film is 300 nm. Both are formed by CVD (Chemical Vapor Deposition). In the present invention, since the TFT substrate does not exist under the base film, the barrier property by the base film is important.

In order to improve the barrier properties of the base film, for example, the base film may have a three-layer structure in which SiN is sandwiched by SiO. In this case, for example, the lower layer SiO film is 300 nm, the SiN film is 100 nm, and the upper layer SiO film is 300 nm. The SiO film and the SiN film can be continuously formed by CVD. In FIG. 4 , the TFT is formed of poly-Si, but there are cases where the TFT is formed of an oxide semiconductor. Since the oxide semiconductor is reduced by hydrogen released from SiN, the oxide semiconductor cannot be brought into direct contact with SiN. In such a case, the uppermost layer of the base film is SiO.

Further, in order to improve the barrier properties, in addition to the SiO film and the SiN film, aluminum oxide (represented by AlO hereinafter) may be added to the base film. The AlO film is formed by sputtering. The AlO film is preferably formed before the SiO film and the SiN film are formed. The AlO film is formed to have a thickness of, for example, about 50 nm.

In FIG. 4 , the semiconductor layer 103 is formed on the second base film 102 . For this semiconductor layer 103, an a-Si film is formed on the second base film 102 by CVD, and converted into a poly-Si film by laser annealing. The poly-Si film was patterned by photolithography.

A gate insulating film 104 is formed on the semiconductor film 103 . The gate insulating film 104 is a SiO film made of TEOS (Tetraethyl Orthosilicate) as a raw material. The film is also formed by CVD. The gate electrode 105 is formed thereover. The gate electrode 105 also serves as the scanning line 11 shown in FIG. 1 . The gate electrode 105 is formed of, for example, a MoW film. When the resistance of the gate electrode 105 or the scanning line 10 needs to be reduced, a gate electrode formed by sandwiching an Al alloy with Ti or the like is used.

The gate electrode 105 is patterned by photolithography, and during the patterning, the poly-Si layer is doped with impurities such as phosphorus or boron by ion implantation, and the source electrode S or the drain electrode D is formed in the poly-Si layer.

Then, the interlayer insulating film 106 is formed by covering the gate electrode 105 with SiO or SiN. The interlayer insulating film 106 is used to insulate the gate electrode 105 from the contact electrode 107 or to insulate the scanning line 11 from the image signal line 12 . Through holes 131 for connecting the video signal line 12 and the semiconductor layer 103 are formed on the interlayer insulating film 106 and the gate insulating film 104 , and through holes 132 for connecting the semiconductor layer 103 and the contact electrode 107 are formed.

A double-gate TFT is formed between the image signal line 12 and the contact electrode 107 , and the double-gate TFT is formed by passing the semiconductor layer 103 under the scanning line 11 twice. Photolithography for forming the through holes 131, 132 in the interlayer insulating film 106 and the gate insulating film 104 may be performed simultaneously.

A contact electrode 107 is formed on the interlayer insulating film 106 . The contact electrode 107 is connected to the pixel electrode 112 via the through hole 130 . The contact electrode 107 and the image signal line 12 are formed simultaneously in the same layer. In order to reduce the resistance of the contact electrode 107 and the image signal line (represented by the contact electrode 107 hereinafter), for example, an AlSi alloy can be used. Since the AlSi alloy produces hillocks or Al diffuses to other layers, a structure in which AlSi is sandwiched between a barrier layer formed of, for example, Ti or MoW, and a cover layer is adopted.

The inorganic passivation film 108 is covered so as to cover the contact electrode 107 to protect the entire TFT. The inorganic passivation film 108 is formed by CVD in the same manner as the first base film 101 and the like. The organic passivation film 109 is formed to cover the inorganic passivation film 108 . The organic passivation film 109 is formed of a transparent photosensitive acrylic resin. Since the organic passivation film is formed after the TFT is completed, there is no problem of heat resistance, so a transparent resin can be used.

The organic passivation film 109 may also be formed of silicone resin, epoxy resin, polyimide resin, or the like other than acrylic resin. Since the organic passivation film 109 functions as a planarizing film, it is formed thick. The film thickness of the organic passivation film 109 is 1.5 to 4.5 μm, and in many cases, it is about 2 μm.

A through hole 130 is formed on the organic passivation film 109 in order to achieve the conduction between the pixel electrode 112 and the contact electrode 107 . Then, ITO (Indium Tin Oxide) as the common electrode 110 is formed by sputtering, and patterning is performed in such a manner that the ITO is removed from the through hole 130 and its periphery. The common electrode 110 can be formed in a planar shape shared by each pixel.

Then, SiN as the capacitor insulating film 111 is formed on the entire surface by CVD. Then, in the through hole 130 , a through hole is formed on the capacitor insulating film 111 and the inorganic passivation film 108 , so as to obtain conduction between the contact electrode 107 and the pixel electrode 112 . The capacitor insulating film 111 forms a storage capacitor between the common electrode 110 and the pixel electrode 112, and is therefore called a capacitor insulating film.

Then, ITO is formed by sputtering, and patterning is performed to form the pixel electrode 112 . The shape of the pixel electrode 112 is shown in FIG. 2 . The alignment film 113 is formed by applying an alignment film material on the pixel electrode 112 by flexographic printing, inkjet, or the like, and firing it. In the alignment treatment of the alignment film 113, in addition to the rubbing method, photo-alignment using polarized ultraviolet rays may be used.

When a voltage is applied between the pixel electrode 112 and the common electrode 110, lines of electric force as shown in FIG. 4 are generated. The liquid crystal molecules 301 are rotated by this electric field, and the amount of light passing through the liquid crystal layer 300 is controlled for each pixel, thereby forming an image.

In FIG. 4 , the opposing substrate 200 is arranged with the liquid crystal layer 300 interposed therebetween. The opposing substrate is formed of transparent resin. Since there is no high temperature process on the opposite substrate side, a transparent resin such as transparent polyimide can be used. In addition, as will be described later, a material without birefringence may be selected. The thickness of the opposing substrate is 5 μm to 10 μm.

Inside the opposing substrate 200, a color filter 201 is formed. The color filter 201 has red, green, and blue color filters formed on each pixel, thereby forming a color image. A black matrix 202 is formed between the color filters 201 and the color filters 201 to improve the contrast of the image.

An overcoat film 203 is formed to cover the color filter 201 and the black matrix 202 . Since the surfaces of the color filter 201 and the black matrix 202 have irregularities, the surfaces are flattened by the overcoat film 203 . On the overcoat film 203, an alignment film 204 for determining the initial alignment of the liquid crystal is formed. For the alignment treatment of the alignment film 204 , a rubbing method or a photo-alignment method is used in the same manner as the alignment film 113 on the TFT substrate 100 side.

For liquid crystal display devices, the efficiency is poor when manufactured one by one, and therefore, a method of manufacturing a mother substrate including many liquid crystal cells and separating each liquid crystal cell from the mother substrate after completion is employed. FIG. 5 is an example of the mother substrate 600 . The example of FIG. 5 is an example in which 60 liquid crystal cells 10 are formed on one mother substrate 600 . In the case of the liquid crystal display device shown in FIG. 1 , much more than 60 liquid crystal cells 10 can be formed on the mother substrate 600 .

6 to 20 are diagrams showing manufacturing steps for realizing the liquid crystal display device shown in FIGS. 1 to 4 . The liquid crystal display device in this invention uses the colored polyimide formed on the glass substrate in the manufacturing process, and removes the glass substrate and the colored polyimide after the liquid crystal display device is completed. 6 to 12 are processed in the state of the mother substrate, and processing is performed for each liquid crystal display device after FIG. 13 .

FIG. 6 is a cross-sectional view showing a state in which the colored polyimide 100 is formed on the glass substrate 90 . The thickness of the glass substrate is, for example, 0.5 mm or 0.7 mm. The colored polyimide 100 is formed on the glass substrate 90 with a thickness of 5 to 10 μm. The colored polyimide 100 is formed by coating a precursor as a liquid with a slit coater or the like, followed by firing and imidization. The heat-resistant temperature of the colored polyimide 100 is higher than that of the transparent polyimide, for example, it has a heat-resistant temperature of 400° C. or more.

FIG. 7 is a cross-sectional view showing a state in which the TFT wiring layer 60 is formed on the colored polyimide 100 . The TFT wiring layer 60 is a concept including the base film 101 to the pixel electrode 112 in FIG. 4 . In FIG. 7 , for the sake of convenience, the TFT wiring layer 60 is divided into a base film 61 and an upper layer 62 above the base film 61 and described.

Since the colored polyimide 100 will be peeled off later, the barrier properties of the base film 61 are important. The base film 61 includes a laminated film of a SiO film and a SiN film, and is formed of a multilayer inorganic insulating film. For the base film 61 , there are cases where the lower layer is a SiN film and the upper layer is a SiO film, and there are also cases where the lower layer is a SiO film and the upper layer is a SiN film. In addition, the base film 61 may have a structure in which the SiN film is sandwiched by the SiO film. In any case, the SiO film and the SiN film can be continuously formed on the colored polyimide by CVD.

The base film 61 may also include an AlO film. In this case, AlO is formed on the colored polyimide 100 by, for example, sputtering, and a SiO film and a SiN film are formed thereon by CVD. The AlO film is formed to be about 10 nm to 50 nm. In addition, although the adhesive force of the AlO film and the colored polyimide 100 is strong, it can peel easily by irradiating a laser beam to an interface.

In the formation of the upper layer 62 formed on the base film 61, especially when poly-Si is used for the semiconductor layer, in the annealing of the semiconductor layer, although the colored polyimide substrate 100 is subjected to a high temperature of 400°C or higher, However, the colored polyimide 100 has a heat resistance of 400° C. or higher. In addition, when an oxide semiconductor is used as the semiconductor layer, if annealing can be performed at a high temperature of 400° C. or higher, the reliability of the properties of the oxide semiconductor is also improved.

FIG. 8 is a cross-sectional view showing a state in which an alignment film 113 for aligning liquid crystal is formed on the TFT wiring layer 60 . In the subsequent drawings, there are cases where the alignment film 113 is included in the TFT wiring layer 60 .

9 is a cross-sectional view showing a state in which the sealing material 50 is formed at the boundary of the liquid crystal cell, and the liquid crystal 300 is dropped on the region surrounded by the sealing material 50 . The sealing material 50 may also be formed on the opposite substrate 200 side. In this case, the liquid crystal 300 is dropped on the opposing substrate 200 side.

FIG. 10 is a cross-sectional view showing a state in which a separately formed opposing substrate 200 is bonded to the side of the colored polyimide 100 via the sealing material 50 . The liquid crystal 300 is sandwiched between the alignment film 113 and the alignment film 204 . The manufacturing process on the opposite substrate 200 side is as follows. First, the opposing substrate 200 formed of a transparent resin such as transparent polyimide is formed with a thickness of 5 to 10 μm on a glass substrate 210 having a thickness of 0.5 mm or 0.7 mm. The color filter layer 220 is formed on the opposing substrate 200 . The color filter layer 220 includes the color filter 201 in FIG. 4 , the black matrix 202 , and the overcoat film 203 . Then, the alignment film 204 is formed on the color filter layer 220 . In the subsequent drawings, the color filter layer 220 may include the alignment film 204 in some cases.

FIG. 11 is a view obtained by turning FIG. 10 upside down. Although the structure of FIG. 11 is upside down, the structure is the same as that described in FIG. 10 . In the state of FIG. 11 , the boundary between the glass substrate 90 and the colored polyimide 100 is irradiated with laser light, and the glass substrate 90 and the colored polyimide 100 are separated by so-called laser ablation.

FIG. 12 is a cross-sectional view showing a state in which the glass substrate 90 is peeled off by laser ablation. In FIG. 12 , the colored polyimide 100 is exposed. Processed in the state of the mother substrate 600 before peeling off the glass substrate 90 . Then, the respective liquid crystal cells 10 are cut out and separated from the mother substrate 600 by dicing or the like.

13 is a cross-sectional view showing a state in which the colored polyimide 100 is removed from each liquid crystal cell 10 by oxygen plasma ashing of PA. The conditions of oxygen plasma ashing are, for example, an O ₂ flow rate of 3000 sccm (Standard Cubic Centimeter per Minutes), 1800 Torr, 2 kW, and 250°C. Under such conditions, the colored polyimide 100 can be ashed and removed at a rate of 10 μm/min.

FIG. 14 is a cross-sectional view showing an apparatus for plasma ashing. 14 is a cross-sectional view showing a state in which the liquid crystal cell 10 is placed on the lower electrode 701 . In FIG. 14 , an upper electrode 702 for forming plasma is arranged opposite to the liquid crystal cell 10 . 14 is a cross-sectional view showing a state in which the periphery of the liquid crystal cell 10 is pressed with a jig 710 and the colored polyimide 100 on the surface of the liquid crystal cell 10 is removed by the plasma 700 .

Although the sealing material 50 is formed around the liquid crystal cell 10 , the sealing material 50 may be damaged by the plasma 700 . In order to prevent this danger, while pressing the periphery of the liquid crystal cell 10 with the jig 710 , the side surface of the liquid crystal cell 10 is covered so that the plasma 700 does not reach the sealing material 50 . The gripper 710 is driven by the motor 711 . In the configuration of FIG. 14 , since the plasma 700 does not reach the sandwiched portion, the colored polyimide 100 is not removed. That is, the colored polyimide 100 partially remains. As long as the portion where the colored polyimide 100 remains is located outside the display region 30 , there will be no problem as a liquid crystal display device.

FIG. 15 is a cross-sectional view showing another example of a plasma ashing apparatus. In the case of FIG. 15 , plasma ashing is also performed for each liquid crystal cell 10 . The difference between FIG. 15 and FIG. 14 is that a mask 720 is formed on the periphery of the liquid crystal cell 10 without a jig. Since the mask 720 covers the entire side surface of the liquid crystal cell 10 , the protection effect on the sealing material 50 is more excellent. Moreover, if it is the mask 720, the shape can be easily changed according to the area|region where the colored polyimide 100 is desired to remain.

In FIGS. 14 and 15 , plasma ashing was performed using the jig 710 or the mask 720, but the colored polyimide 100 could not be removed from the clamped or masked portion. When it is planned to remove the colored polyimide 100 from the entire surface of the liquid crystal cell 10 , the liquid crystal cell 10 may simply be placed on the lower electrode 701 .

FIG. 16 is a cross-sectional view showing a state in which the colored polyimide 100 has been removed. In FIG. 16 , the thickness of the TFT wiring layer 60 is only several μm even including the thickest organic passivation film, and the mechanical properties are extremely weak. Therefore, in this case, the operation is difficult.

Therefore, as shown in FIG. 17 , the lower polarizer 401 is attached to the TFT wiring layer 60 . The thickness of the main body of the polarizing plate 401 is about 100 μm, and the adhesive material for sticking is about 10 μm. Therefore, it is sufficient as a reinforcing material. The polarizing plate 401 is an essential element for the liquid crystal display device, and therefore, attaching the polarizing plate does not cause an increase in the process burden.

FIG. 18 is a cross-sectional view showing a state in which FIG. 17 is turned upside down for processing the opposite substrate 200 side. FIG. 18 is only the upside down of FIG. 17 , and the structure is the same as that of FIG. 17 . In FIG. 18 , the interface between the opposing substrate 200 and the glass substrate 210 is irradiated with laser light, and the glass substrate 210 is removed from the opposing substrate 200 by laser ablation. FIG. 19 is a cross-sectional view showing a state in which the glass substrate 210 is peeled from the opposing substrate 200 .

20 is a cross-sectional view showing a state in which the upper polarizing plate 402 is attached to the opposing substrate 200 formed of a transparent resin from which the glass substrate 210 is removed. The upper polarizer 402 is attached only to the portion corresponding to the opposing substrate 200 . On the other hand, the lower polarizing plate 410 is attached to the terminal region 40 in addition to the display region 30 . This is to mechanically strengthen the terminal area 40 . In addition, as shown in Example 3, 4, etc., by reinforcing the terminal area 40 by other methods, the lower polarizing plate 401 may be attached only to the display area 30.

The plasma ashing in FIG. 13 is performed for the individual liquid crystal cells 10 , but if the apparatus allows, the plasma ashing may be performed in the state of the mother substrate 200 and then separated into the individual liquid crystal cells 10 . In this case, the colored polyimide 100 can be removed from the entire surface of the liquid crystal cell 10 , and if a part of the colored polyimide 100 needs to remain, ashing may be performed using a mask.

In this way, according to the present invention, a flexible liquid crystal display device can be formed without a TFT substrate. Therefore, the liquid crystal display device can be formed thin. In addition, the transparent polyimide generally used as a TFT substrate has birefringence characteristics. Therefore, light passing through the transparent polyimide is retarded. The birefringence Δn of the transparent polyimide was 0.005. When the thickness of the transparent polyimide was 10 μm, the retardation amount Δn·d was 50 nm. That is, due to this influence, a decrease in contrast due to the appearance of black occurs.

In the present invention, since there is no TFT substrate formed of polyimide, the above-mentioned retardation can be prevented from occurring, and high contrast can be maintained. In addition, in this invention, the opposing board|substrate 200 formed of resin exists on the opposing board|substrate side. However, since there is no high temperature process on the opposite substrate 200 side, there is a degree of freedom in the selection of resin. That is, a transparent resin material that does not have birefringence or has little birefringence can be selected. Therefore, it is possible to have a configuration in which a reduction in contrast is prevented.

[Example 2]

In Example 1, in the manufacturing process, a colored polyimide was formed on a glass substrate, a base film, a TFT, etc. were formed on the colored polyimide, the glass substrate was finally removed, and the coloring was removed by plasma ashing. Polyimide.

In this example, in the manufacturing process, the a-Si film 95 was used instead of the colored polyimide. If the a-Si film 95 is used, the a-Si film 95 can be removed simultaneously with the removal of the glass substrate 90 by laser ablation, so that the process of plasma ashing can be omitted.

21 to 23 are cross-sectional views illustrating the manufacturing process of Embodiment 2. FIG. FIG. 21 is a cross-sectional view showing a state in which the a-Si film 95 is formed on the glass substrate 90 . The a-Si film 95 is formed to have a thickness of, for example, 50 nm. FIG. 22 is a cross-sectional view showing a state in which the TFT wiring layer 60 is formed on the a-Si film 95 . The configuration of the TFT wiring layer 60 is the same as that described in the first embodiment. In FIG. 22, compared with FIG. 7 of Example 1, instead of the colored polyimide 100, a-Si95 is formed.

The processes of FIGS. 8 to 11 of Embodiment 1 are also the same in Embodiment 2. As shown in FIG. which is,

In Example 2, in FIGS. 8 to 11 of Example 1, the colored polyimide was replaced with a-Si.

23 is a cross-sectional view showing a state in which the glass substrate 90 is removed by laser ablation in Example 2. FIG. At this time, the a-Si film 95 is removed together with the glass substrate 90 . Therefore, a process of plasma ashing is not required. The other structures are the same as those shown in FIG. 12 of the first embodiment.

In FIG. 23 , the a-Si film 95 is peeled off together with the glass substrate, but since the adhesive force between a-Si and glass is not strong, the a-Si film 95 may adhere to the base film side after laser ablation. Even in this case, since a-Si is transparent, it still does not affect the image.

Subsequent processes in Example 2 are the same as those in FIGS. 16 to 20 of Example 1. FIG. In addition, the configuration of the completed liquid crystal display panel is also the same as that described in FIGS. 1 to 4 . In addition, the effect of Example 2 is also the same as the effect demonstrated in Example 1.

[Example 3]

According to the liquid crystal display device, there is a usage method in which the outer shape of the display device is reduced by keeping the display region 30 flat and bending the terminal region 40 for use. FIG. 24 is a plan view showing such a liquid crystal display device. In FIG. 24 , a TFT wiring layer 60 extending from the display region 30 is formed in the terminal region 40 . Furthermore, the flexible wiring board 500 is connected to the terminal region 40 . In FIG. 24 , the driver IC 41 is mounted on the flexible wiring board 500 so as not to hinder the bending of the terminal region 40 .

For the configurations of Examples 1 and 2, the lower polarizer 401 also extends to the terminal region 40 . Therefore, the mechanical strength is maintained also in the terminal region 40, but since the polarizing plate 401 has strong mechanical strength, it is difficult to bend it with a small radius of curvature. Although it is possible to prevent the lower polarizer from extending to the terminal region 40 , if this is done, the mechanical strength of the terminal region 40 becomes extremely weak. FIG. 25 is a cross-sectional view showing such a situation.

In FIG. 25 , the terminal region 40 is constituted by only the TFT wiring layer 60 . The thickness tt of the TFT wiring layer 60 is only several μm in total even when the thickness of the organic passivation film 109 is added. Therefore, a display device with high mechanical reliability cannot be produced.

FIG. 26 and FIG. 27 are diagrams showing the configuration of the first example of the present embodiment for taking countermeasures against this. 26 is a plan view showing a first example of the second embodiment. In FIG. 26 , the opposing substrate 200 extends in the terminal region 40 . The opposing substrate 200 extends to the terminal portion to which the flexible wiring substrate 500 is connected. In FIG. 26 , the mechanical strength of the terminal region 40 is maintained by the opposing substrate 200 . Since the opposing substrate 200 is formed of, for example, a polyimide substrate having a thickness of 5 to 10 μm, mechanical strength and flexibility can be sufficiently maintained.

FIG. 27 is a cross-sectional view showing a state in which the terminal region 40 is bent in the liquid crystal display device shown in FIG. 26 . In FIG. 27, the terminal region 40 of the liquid crystal display device is bent. The thickness tt1 of the terminal region 40 is only 15 μm or less even if the thickness tt1 of the opposite substrate is taken into account, so that the bending radius of curvature can be sufficiently reduced.

In FIG. 27 , the front end of the flexible wiring board 500 overlaps with the counter board 200 . The flexible wiring substrate 500 is electrically connected to the TFT wiring layer 60 in the front end portion of the terminal region 40 which is not covered by the opposite substrate 200 . With the configuration shown in FIG. 27 , the mechanical strength of the terminal region 40 can be maintained, and bending can be performed with a small radius of curvature.

28 is a plan view showing a second aspect of the third embodiment. The difference between FIG. 28 and FIG. 26 as the first embodiment is that the colored polyimide 100 remains in the terminal area 40 , and the mechanical strength of the terminal area 40 is enhanced. Accordingly, the opposite substrate 200 does not exist on the upper side of the terminal region 40 . The opposing substrate 200 is formed only in the display area. The colored polyimide 100 may be formed by masking a portion that is intended to remain when the colored polyimide 100 is removed from the display area 30 by plasma ashing.

FIG. 29 is a cross-sectional view showing features of the second aspect. In FIG. 29 , the colored polyimide 100 remains on the lower surface of the terminal region 40 . Since the colored polyimide 100 is removed from the display area 30, the display quality is not impaired. In addition, since the colored polyimide 100 is formed on the back surface of the terminal region 40, the connection of the flexible wiring board 500 is not hindered.

In FIG. 29 , the TFT wiring layer 60 is bonded to the counter substrate 200 using the sealing material 50, and the liquid crystal 300 is sealed inside. The colored polyimide 100 overlaps with the sealing material 50 in plan view. This is to prevent the generation of only the portion of the TFT wiring layer 60 . There is no problem as long as the range d1 in which the sealing material 50 and the colored polyimide 100 overlap is the width of the sealing material 50 .

FIG. 30 is a cross-sectional view showing a state in which the terminal region 40 of the liquid crystal display device of FIGS. 28 and 29 is bent. Both the upper polarizer 402 and the lower polarizer 401 are arranged corresponding to the display area 30 and do not affect the bending of the terminal portion 40 . The colored polyimide 100 is present in the bent portion, but the thickness of the colored polyimide 100 is 5 to 10 μm, and the total thickness tt2 of the terminal region 40 is only 15 μm or less, so that it can be folded with a small radius of curvature without any problem. Angled terminal area 40 .

31 to 33 are diagrams showing a third aspect of the third embodiment. 31 is a plan view showing a liquid crystal display device according to a third embodiment. FIG. 31 features terminal regions 40 . As shown in FIG. 31 , the flexible wiring board 500 is connected on the back side of the terminal region 40 . That is, the terminal wiring is formed on the back side of the terminal region 40 .

FIG. 32 is a cross-sectional view of FIG. 31 . In FIG. 32 , the insulating layer 16 includes a base film 101 , a gate insulating film 104 , and an interlayer insulating film 106 . On the insulating layer 16 , for example, in the display region 30 , the video signal line 12 is formed, and the lead wire 15 connected to the video signal line 12 extends in the terminal region 40 . In addition, in the terminal region 40 , the lead wires 15 are exposed to the back surface of the insulating layer 16 through the through holes formed in the insulating layer 16 . The insulating layer 16 is only about 1 μm in total even if it is three layers. The through holes of the terminal area 40 may be formed simultaneously with the formation of the through holes in the display area 30 .

In FIG. 32 , the opposing substrate 200 formed of a transparent resin is formed up to the end of the terminal region 40 in a plan view. Therefore, the mechanical strength of the terminal region 40 can be secured by the opposing substrate 200 . In FIG. 32 , since the flexible wiring board 500 is connected on the back side of the insulating layer 16, even if the counter board 200 is formed to the end of the terminal region 40, the connection of the flexible wiring board 500 is not problematic.

FIG. 33 is a cross-sectional view showing a state in which the terminal region 40 is bent in the configuration of FIG. 32 . Since the thickness of the counter substrate 200 is 5 μm to 10 μm, the total thickness tt3 of the terminal region 40 is only 15 μm or less, which does not hinder the bending of the terminal region 40 with a small curvature radius. In addition, as shown in FIG. 33 , even if the opposing substrate 200 is extended to the end of the terminal region 40 , the connection of the flexible wiring substrate 500 is not hindered.

34 is a cross-sectional view showing a fourth aspect of the third embodiment. FIG. 34 is a configuration in which a resin 70 for mechanical reinforcement is applied to the terminal region 40 with respect to the configuration of FIG. 25 . As a resin material, a silicone resin, an acrylic resin, an epoxy resin, etc. can be used, but if it is an ultraviolet curable resin, the handleability is excellent.

In FIG. 34 , the end of the resin 70 overlaps the opposing substrate 200 or the upper polarizer 402 on the display area side so that the resin 70 does not peel off from the terminal area 40 against the bending stress. Moreover, it overlaps with the edge part of the flexible wiring board 500 on the flexible wiring board 500 side. In FIG. 34 , the opposing substrate 200 protrudes outward from the upper polarizing plate 402 in many cases, and therefore, the resin 70 can overlap with the end portion of the opposing substrate 200 .

[Example 4]

Embodiment 4 has a configuration in which the terminal region 40 is omitted in plan, and all the flexible wiring boards and the like are arranged on the back side of the liquid crystal display panel, thereby making it possible to further reduce the outer shape of the liquid crystal display device. 35 is a plan view of the liquid crystal display device of Example 4. FIG. In FIG. 35, the terminal region 40, the flexible wiring board 500, and the like do not exist on the surface. Other configurations are the same as those in FIG. 1 .

FIG. 36 is a cross-sectional view taken along line B-B of FIG. 35 . In Fig. 36, there is no TFT substrate. On the insulating layer 16 formed of the base film 101 , the gate insulating film 104 , and the interlayer insulating film 106 , the lead wires 15 connected to the display region extend to the vicinity of the end of the interlayer insulating film 106 . A through hole is formed in the insulating layer 16 in the vicinity of the end portion of the interlayer insulating layer 106 , and is electrically connected to the driver IC 41 arranged on the back side of the insulating layer 16 .

The bumps 42 in FIG. 36 are used in a broad sense such as connection terminals. The bumps 42 of the driver IC 41 are connected to the lead wires 15 via, for example, through holes, using an anisotropic conductive film 45 or the like. In addition, the terminal wiring 45 and the flexible wiring board 500 are also connected via the bumps 42 . In the configuration shown in FIG. 36 , the terminals are formed on the back surface of the liquid crystal display panel and are connected to the driver IC 41 and the flexible wiring board 500 on the back surface. Therefore, even if the flexible wiring board 500 is not bent, the terminals can be connected to the back surface of the liquid crystal display panel. The flexible wiring board 500 and the driver IC 41 are arranged on the rear surface.

In FIG. 36 , the organic passivation film 109 is formed so as to cover the lead wires 15 . The inorganic passivation film is omitted in FIG. 36 . A capacitor insulating film 111 is formed on the organic passivation film 109, and an alignment film 113 is formed on the capacitor insulating film.

In FIG. 36 , a black matrix 202 and a color filter 201 are formed on a counter substrate 200 made of resin, and an overcoat film 203 is formed thereon. An alignment film 204 is formed to cover the overcoat film 203 . The sealing material 50 adheres the alignment film 113 and the alignment film 204, and seals the liquid crystal inside.

In FIG. 36 , the polarizer 402 is attached to the opposing substrate 200 . The upper polarizing plate 402 is formed to the end of the opposing substrate 200 . That is, since there is no terminal region on the front surface side of the display device, the upper polarizing plate 402 is arranged to the end of the display device. On the other hand, since the terminal is formed on the back side of the TFT wiring layer 60, the lower polarizer 401 is arranged so as to avoid this area. Since the lower polarizer 401 covers the range of the display area 30, there is no problem in display quality.

FIG. 37 is a rear view of FIG. 35 . In FIG. 37 , the lower polarizing plate 401 covers the entire surface except for the portion of the side where the terminals connected to the driver IC 41 and the flexible wiring board 500 are formed. The terminal formation region is also narrow, and is arranged in a region overlapping the sealing material 50 in plan view. The lower polarizing plate 401 is formed in a sufficient range so as to cover the display area. As shown in FIG. 37 , the flexible wiring board 500 can be arranged on the back surface of the liquid crystal display panel without being bent.

Although the backlight is omitted in FIG. 37 , the backlight is disposed between the flexible wiring board 500 and the liquid crystal display panel.

Claims (20)

1. liquid crystal display device, made of between liquid crystal is clamped in inorganic insulating membrane and is formed by resin counter substrate Liquid crystal display device, the inorganic insulating membrane are formed with multiple pixels with TFT, and the feature of the liquid crystal display device exists In being bonded with lower polarizing film on the inorganic insulating membrane.

2. liquid crystal display device as described in claim 1, which is characterized in that the lower polarizing film is attached at using adhesives The inorganic insulating membrane.

3. liquid crystal display device as described in claim 1, which is characterized in that the inorganic insulating membrane has silicon oxide film and nitrogen The laminate structures of SiClx film.

4. liquid crystal display device as described in claim 1, which is characterized in that the inorganic insulating membrane is clamped by silicon oxide film Silicon nitride film and constitute, the lower polarizing film is attached at the silicon oxide film.

5. liquid crystal display device as described in claim 1, which is characterized in that the inorganic insulating membrane is silicon oxide film, nitridation Silicon fiml, the laminate structures with pellumina.

6. liquid crystal display device as claimed in claim 5, which is characterized in that the lower polarizing film is attached at the aluminium oxide Film.

7. liquid crystal display device as described in claim 1, which is characterized in that the inorganic insulating membrane extends to terminal area, It is connect in the terminal area with circuit board.

8. liquid crystal display device as claimed in claim 7, which is characterized in that the lower polarizing film prolongs in the terminal area It stretches, and Nian Jie with the inorganic insulating membrane.

9. liquid crystal display device as claimed in claim 7, which is characterized in that the counter substrate is prolonged in the terminal area It stretches, and covers the inorganic insulating membrane.

10. liquid crystal display device as claimed in claim 7, which is characterized in that described inorganic exhausted in the terminal area The back side of velum is formed with polyimide film.

11. liquid crystal display device as claimed in claim 10, which is characterized in that the polyimide film with a thickness of 5 to 10 μ m。

12. liquid crystal display device as claimed in claim 7, which is characterized in that formed in the surface side of the inorganic insulating membrane The lead-out wire extended from display area, the lead-out wire via the through-hole for being formed in the inorganic insulating membrane and with it is described inorganic The terminal of the back side of insulating film connects, and the terminal is connect with the circuit board.

13. liquid crystal display device, to be formed between liquid crystal is held on inorganic insulating membrane and is formed by resin counter substrate Liquid crystal display device, the inorganic insulating membrane is formed with multiple pixels with TFT, and the feature of the liquid crystal display device exists In,

It is bonded with lower polarizing film on the inorganic insulating membrane, is not configured between the inorganic insulating membrane and the lower polarizing film Glass or polyimides.

14. liquid crystal display device as claimed in claim 13, which is characterized in that the inorganic insulating membrane extends to terminal region Domain is connect in the terminal area with circuit board, the back side shape of the inorganic insulating membrane in the terminal area At there is polyimide film.

15. the manufacturing method of liquid crystal display device, which is characterized in that

Polyimides is formed on the first glass substrate,

The inorganic insulating membrane comprising multilayer is formed on the polyimides,

The layer containing TFT is formed on the inorganic insulating membrane,

It is opposed with the layer containing TFT, clamping liquid crystal and configure counter substrate, the counter substrate is by being formed in the second glass The transparent resin of substrate is formed,

Then, first glass substrate and the polyimides are removed, lower polarizing film is attached at the inorganic insulating membrane,

Then, second glass substrate is removed.

16. the manufacturing method of liquid crystal display device as claimed in claim 15, which is characterized in that the inorganic insulating membrane includes SiO film and SiN film, the SiO film and the SiN film are formed by the way that CVD is laminated.

17. the manufacturing method of liquid crystal display device as claimed in claim 16, which is characterized in that the inorganic insulating membrane also wraps Salic film, the pellumina are formed by sputtering.

18. the manufacturing method of liquid crystal display device as claimed in claim 15, which is characterized in that removed by plasma ashing Remove the polyimides.

19. the manufacturing method of liquid crystal display device, which is characterized in that

Si film is formed on the first glass substrate,

The inorganic insulating membrane comprising multilayer is formed on the Si film,

The layer containing TFT is formed on the inorganic insulating membrane,

It is opposed with the layer containing TFT, clamping liquid crystal and configure counter substrate, the counter substrate is by being formed in the second glass The transparent resin of substrate is constituted,

Then, first glass substrate is removed, lower polarizing film is attached at the inorganic insulating membrane or the Si film,

Then, second glass substrate is removed.

20. the manufacturing method of liquid crystal display device as claimed in claim 19, which is characterized in that inorganic insulating membrane includes SiO Film and SiN film, the Si film, the SiO film, the SiN film are formed by CVD.