TW200416446A - Pixels of in-plane switching LCD and manufacturing process - Google Patents

Abstract

The present invention discloses pixels of in-plane switching (IPS) LCD and manufacturing process of the same whose reflector provides nano scale surface roughness to scatter light source and raise contrast. Because the coarse surface is of nano scale, the scattering effect aspect will have greater scattering angle and smoothing effect. Even if the reflection won't vary dramatically with view angle, good anti-flare effect can still be obtained. Furthermore, the rough surface is formed by utilizing the relation between crystallization of material characteristics without additional mask.

Description

200416446 V. Description of the invention (1) Field of the invention The present invention relates to a lateral electric field liquid crystal display, and more particularly to a pixel and a process for a transverse electric field liquid crystal display having a nano-level rough surface reflective plate. BACKGROUND OF THE INVENTION In the conventional art, a liquid crystal display (LCD) uses a TN mode and a stn mode. However, the LCDs of the TN mode and the STN mode have the disadvantage of a narrow viewing angle. Therefore, some people have proposed a wide-angle horizontal Electric field (in-plane switching; lps). In addition to the wide viewing angle, the IPS mode LCD also has the advantages of no compensation film and fast response time. The manufacturing process is one less than that of the TN mode LCD. However, the IPS The pixel electrode (pixei eiec ^ r0 (je) and counter electrode) of the mode LCD are made of opaque metal and have a smooth surface. Therefore, the reflection is specular, which reduces the contrast. 'A rough surface made of organic materials such as' resin 'can be formed under the pixel electrode and the common electrode to improve this disadvantage. However,' increasing the number of photomasks for the organic material will increase the manufacturing process. Complexity and cost, and the heat resistance of organic materials is not good, about 250 degrees. In addition, because the height difference of the rough surface is too large, Between uin and i.5um, the gap of the liquid crystal display is changed too much, so that the decrease of the reflected light efficiency is reduced from the ideal 丨 〇% to 60% ~ 85%. Therefore, 'a kind of nanometer A horizontal electric field liquid crystal display that has a rough surface and can reduce the number of photomasks is still desired.

200416446 V. Description of the invention (2) Object and summary of the invention One of the objects of the present invention is a day field element and a process for a horizontal electric field liquid crystal display with a nano-scale rough surface. One object of the present invention is to provide a pixel and a process for a lateral electric field liquid crystal display with a reduced number of photomasks. According to the present invention, a pixel and a process for a lateral electric field liquid crystal display. The pixel in the first embodiment includes a first structure on a substrate, and has a nano-scale rough surface to scatter light sources and improve contrast. A structure includes a first portion and a second portion, a second structure on the first portion to form a switching element, a liquid crystal layer on the second structure and the second portion, and a third structure on the liquid crystal layer The second part is a plurality of reflective plates having the nano-level rough surface, the third structure is an optical stack, and the liquid crystal layer may be a positive type or a negative type liquid crystal. The rough surface is formed due to the relationship between the crystal and the characteristics of the material itself. Since the first part and the second part of the reflective plate are made together, the liquid crystal display of the present invention only needs four masks, which is better than the conventional scattered liquid crystal display. The required eight or nine masks are reduced by half, which greatly reduces the cost, and because the rough surface is nano-level, the scattering effect will have a larger scattering angle and a smooth effect, that is, reflectivity. Does not change drastically with the viewing angle, but also has a good anti-glare effect (Anti-glare). In addition, since the height difference of the rough surface is smaller than the height difference of the rough surface of the current scattered inner layer reflecting plate, the change of the gap of the liquid crystal layer (1 iquidcrysta 1 ce 1 1) can be reduced, and the reflected light efficiency can be maintained at Best condition. The reflecting plate is produced by an inorganic thin film process.

200416446 V. Description of the invention (3) Production, so it is more resistant to high temperature than general organic materials. The pixel substrates of the second and third embodiments include a substrate, a thin film transistor on the substrate, a plurality of reflective plates, a protective layer covering the plurality of reflective plates, and a second metal layer on the substrate. The protective layer passes through the first protective layer and is connected to one of the plurality of reflective plates, wherein each of the reflective plates includes a micro scattered layer with a nano-scale coarse chain surface, and a reflective layer. The layer is on the micro-scattered layer and conforms to the rough surface of the micro-scattered layer to have the rough surface. The reflective layer is the same metal as the gate electrode of the thin film transistor. The slightly scattered layer includes a conductive layer composed of I T0 and an insulating layer on the conductive layer. Due to the characteristics of the material of the insulating layer, the rough surface with a nanometer level is formed, and the reflective layer is highly reflective. Rate metal composition. In the second and third embodiments, since the gate of the thin film transistor and the reflecting plate are not made together, an additional photomask must be added. DETAILED DESCRIPTION FIG. 1 is an embodiment of a pixel structure 100 of a lateral electric field liquid crystal display of the present invention, which is a transflective LCD including a first structure having a nanometer-level rough surface on a substrate 102. The first structure includes a first part and a second part, wherein the first part is a gate electrode 1 1 0, and the second part is a reflective plate 1 1 2 and 1 1 4; a protective layer 1 1 6 covers the first part Structure, a second structure on the protective layer 1 16 above the gate electrode 110, the second structure includes a drain electrode 1 24, a source electrode 1 26, and an amorphous stone The channel region formed by the semiconductor thin film 1 1 8 is between the drain electrode 1 2 4 and the source electrode 1 2 6. The gate electrode 1 1 0 and the second structure form a switching element and are thin.

200416446 V. Description of the invention (4) The film transistor 1 2 2 and the drain electrode 1 2 4 are connected to the reflective plate 114 through the contact hole 120 on the protective layer 1 1 6. When a voltage is applied to the When a thin film transistor is formed, a lateral electric field E is generated between the reflective plates 1 12 and 1 1 4 to twist the liquid crystal molecules 1 3 2 and another protective layer 1 2 8 covers the second structure. A rear polarizing film is on the substrate. Below 102, a liquid crystal layer 130 is sandwiched between the protective layer 128 and the first and second structures, where the liquid crystal layer 130 may be a positive type liquid crystal or a negative type liquid crystal. In this embodiment, the liquid crystal layer is a negative type liquid crystal. The preferred implementation ranges of the birefringence index and phase retardation are respectively 0.05 _ 0 ·; [4 and 50-4 1 0 nm. In addition, the thin film transistor of this embodiment 丨 2 2 series N Μ 〇 S transistor (η-type Metal- Oxide-Semiconductor transistor) ° The second structure includes a shape filter 1 3 8, a scattering film between the color light filter 1 3 8 and the liquid crystal layer 1 3 0, A black matrix 1 3 6 on the multi-stained light polarizing film 142 is on top of the film, where the black matrix 136 is not a cr metal material but is made of black It is made of black resin. The structures of the gate electrode 110 and the reflective plates 112 and 114 include:-the conductive layer 10.4 is composed of το or IZ0, an insulating layer 106 is composed of silicon nitride (SiNx) on the conductive layer, and A reflective layer 108 is made of a metal with high reflectivity on the insulating layer, such as Ming, silver, and Ming alloy. When the insulating layer 106 is on the conductive layer 104, and due to the relationship between the crystal and the characteristics of the material itself Furthermore, a nano-level rough surface is formed on the surface of the insulating layer 106. Therefore, it is not necessary to add an additional resin layer to form a rough surface as in conventional techniques. Because the reflecting plates U2 and U4 are connected to the question electrode 11〇_ The same production, so you can

200416446 V. Description of the invention (5) Four masks to make liquid crystal display! The daytime structure 100 ′ is less than half the number of masks compared with the conventional 8- or 9-mask process of the scattered transparent reflection LCD, so the cost can be greatly reduced. The rough surfaces of the reflecting plates 112 and 114 have smaller fluctuations and fluctuation periods. Therefore, in terms of the scattering effect, there is a larger scattering angle and a gentle effect, that is, the reflectivity does not change drastically with the viewing angle. Very good anti-glare effect, can also keep the reflected light efficiency at the best condition, and because the inorganic thin film process can be used, it can be more resistant to south temperature than reflective elements using organic materials. FIG. 2 is a top view of the pixel structure 100 of the liquid crystal display 1, wherein the source electrode 1 2 6 is connected to the bus line 1 2 7. Fig. 3 is a comparison between the rough surface of the reflecting plate used in the present invention and the rough surface of the conventional scattered reflection plate, and Fig. 3 (A) shows the rough surface of the conventional scattered reflection plate, whose fluctuation difference is 0.5. Between um and 1.5um, the undulation period L is between 5 um and 2 Oum. Figure 3 (B) is the rough surface of the reflecting plate used in the present invention, and its height difference H 'is between 5nm and 50nm. L 'is below 20nm, because the difference in height between the rough surface of the ultra-micro-reflective plate is small, so the change of the gap between the liquid crystal molecules is reduced, so that the reflected light efficiency is kept at the optimal state, and the scattering angle is wider and more uniform. Figures 4 to 8 are top and cross-sectional views of the pixel structure 100 process steps of the liquid crystal display. First, as shown in Figure 4, a conductive layer 104 composed of IT0 is deposited on the substrate 102, and then a layer is deposited. An insulating layer 106 made of silicon nitride (S i NX) is on the conductive layer 104. When the insulating layer 1 0 6 is formed on the conductive layer 104, and due to the relationship between the crystal and the characteristics of the material itself,

Page 10 200416446 V. Description of the invention (6) The system further forms a nano-scale rough surface on the surface of the insulating layer 104, as shown in FIG. 3 (B), and then on the insulating layer 104 In order to form a reflective layer composed of a metal with high reflectivity, for example, aluminum, silver, or aluminum alloy, the rough surface of the reflective layer 108 and the insulating layer 104 is conformal to have the nanometer level. The rough surface is then #etched into the reflective layer 108, the insulating layer 10 and the conductive layer 104 to form electrodes 1 10, 1 12 and 1 1 4 having a nano-scale rough surface. With reference to FIG. 5 ', a protective layer 1 1 6 is formed to cover the electrodes 1 0, 1 12 and 1 1 4 and an amorphous semiconductor film 1 1 8 is formed over the electrode 1 10. Next, as shown in FIG. 6, the protective layer 1 1 6 over the electrodes 1 1 4 is etched until the electrodes 1 1 4 are exposed to form a through hole 120. Next, a second metal layer is formed on the protective layer 116, and the second metal layer is partially etched to form a thin film transistor 1 2 2. As shown in FIG. 7, the gate electrode of the thin film transistor 1 2 2 The electrode 1 1 0, and the second metal layer after the rest of the time is its electrode electrode 1 2 4 and the source electrode 1 2 6. The electrode electrode 1 2 4 is connected to the reflection plate through the through hole 1 2 0 1 1 4 and the source electrode 1 2 6 is connected to the bus line 1 2 7. Finally, a second protective layer 1 2 8 is deposited to cover the thin film transistor 122, as shown in FIG. In the eighth figure, the area ratio of the light-transmitting region 144 and the reflection region composed of the reflection plates 112 and 114 is between 10% and 400%. Figures 9 to 13 are the manufacturing steps of another transverse electric field thin film transistor structure 2000. The manufacturing method is the same as that of the transverse electric field thin film transistor structure 100 described above. The difference between the structures lies in the thin film transistor structure. The reflecting plates 202 and 204 of 200 are curved. FIG. 14 is another embodiment of the bottom plate in the pixel of FIG. 1. The bottom plate 300 includes a substrate 302, a thin film transistor 304 on the substrate 302, and an insulating layer.

Page 11 200416446 V. Description of the invention (7) 30 6 on the substrate 302, the reflective plates 308 and 310 on the insulating layer 306, a protective layer 312 covering the reflective plates 308 and 310, and a metal layer 314 on the protective layer 312 Through the protective layer 3 1 2 to the reflective plate 3 1 0, and another protective layer 3 1 6 covers the metal layer 314, wherein the thin film transistor 30 4 series PMOS transistor (p-type Metal-Oxide-Semiconductor transistor), and the drain layer 3 0 4 2 of the metal layer 3 14 and the thin film transistor 3 0 4. The reflective plates 3 0 8 and 310 each include a slightly scattered layer consisting of an IT 0 layer 3 1 8 and an insulating layer 3 2 0. The insulating and layer 3 2 0 has a nano-scale rough surface and a reflective layer 3 2 2 The insulating layer 3 2 0 is conformal to the rough surface of the insulating layer 320 and has the rough surface. The reflective layer 322 is the same metal as the gate electrode 3 0 4 4 of the thin film transistor 3 0 4. In addition to the aforementioned materials, the insulating layer 3 2 0 may be composed of amorphous silicon or polycrystalline silicon. In addition to the above structure, the micro-scattered layer can also be formed by a seed layer and an insulating layer through a high-temperature sintering process. In this embodiment, the gates 3 04 of the transistor 3 0 4 and the reflective plates 3 08 and 3 1 0 are not manufactured together. Therefore, a photomask is required more than in the first embodiment. Fig. 15 is another embodiment of the bottom plate in Fig. 1. The structure of the bottom plate 4 Q 0 is the same as that of the bottom plate 300. It includes a substrate 30 2, a thin film transistor 304, an insulating layer 3 0 6 and a reflective plate 3 0 8 And 310, a protective layer 312, a metal layer 314, and another protective layer 316, the difference is that the thin film transistor 304 series CMOS transistor (Complementary Metal-Oxide-Semiconductor transistor) ° The description of the preferred embodiment is for the sake of clarity, and it is not intended to limit the present invention to precisely the form 7 disclosed above, or to modify or change it from the teaching of the embodiment of the present invention. To explain the principles of the invention and to familiarize yourself with the technology ^

Page 12 200416446 V. Description of the invention (8) Various embodiments are used to select and describe the present invention in practical applications. The technical idea of the present invention is intended to be determined by the following patent application scope and its equality.

Page 16 200416446 Schematic description For those skilled in the art, from the following detailed description and accompanying drawings, the present invention will be more clearly understood, its above and other objectives and advantages will become It is more obvious, in which: FIG. 1 is an embodiment of the horizontal electric field liquid crystal display pixel of the present invention; FIG. 2 is a top view of the daylight structure of the liquid crystal display; FIG. 3 (A) is a rough wheel surface of the current reflecting plate; ^ Fig. 3 (B) is a rough surface of a reflective plate used in the present invention; Fig. 4 ~ Fig. 8 are the process steps of the transverse electric field thin film transistor structure of Fig. 1; Fig. 9 ~ Fig. 13 are another transverse electric field film transistor Process steps for crystal structure. FIG. 14 is another embodiment of a base plate in a pixel of FIG. 1; and FIG. 15 is another embodiment of a base plate in a pixel of FIG. Description of the reference numerals 100 pixel structure 101 Polarizing film 102 Base 104 Conductive layer 1 0 6 Insulating layer 108 Reflective layer 110 Question electrode 1 1 2 Reflective plate

Page 14

V 200416446

Brief description of drawings on page 15 114 Reflective plate 116 Protective layer 118 Amorphous silicon semiconductor film 120 Through hole 122 Thin film transistor 124 Drain electrode of thin film transistor 126 Source electrode of thin film transistor 127 Bus line 128 Protective layer 130 Liquid crystal layer 132 Liquid crystal molecules 134 Scattering film 136 Black matrix 138 Color filter 140 Compensation film 142 Polarizing film 144 Light transmission area 200 Thin film transistor structure 202 Bending reflection plate 204 Bending reflection plate 300 Pixel base plate 302 Substrate 304 Thin film transistor 3 0 42 Thin film transistor 3 0 4 > and 200416446 Brief description of the diagram 3 0 4 4 Thin film transistor 3 0 4 Gate 3 0 6 Insulating layer 3 0 8 Reflective plate 310 Reflective plate 312 Protective layer 314 Metal Layer 316 Protective layer 318 ITO layer 3 2 0 Insulating layer 3 2 2 Reflective layer 4 0 0 Pixel base plate 4 0 2 Thin film transistor

Page 16

Claims (1)

200416446 6. Scope of patent application 1. A transverse electric field liquid crystal display Is pixel 1 includes a first structure on a substrate with a nano-scale rough surface to scatter light sources and improve contrast. The first structure includes A first part and a second part; a second structure on which a switching element is formed; a liquid crystal layer on the second structure and the second part; and a third structure on the liquid crystal layer. 2. For example, the pixel in the first patent application range, wherein the liquid crystal layer is a positive type liquid crystal and has a complex refractive index, and the optimal range of the refractive index is 0.05 to 0.12 ° 3. The pixel of item 1, wherein the liquid crystal layer is a negative type liquid crystal and has a complex refractive index and a phase retardation. The optimal range of the refractive index is 0 · 0 5-0 · 1 4 and the optimal phase retardation is. The range is 1 50-4 10 nm. 4. The pixel of the first item of the patent application range, wherein the rough surface has a range of 5 to 50 nm. 5. The pixel according to item 1 of the patent application range, wherein the rough surface has a volt period ranging from 10 nm to 500 nm. 6. The pixel according to item 1 of the scope of the patent application, wherein the structure of the first structure includes: a slightly scattered layer having the nano-scale rough seam surface on the substrate; a reflective layer on the slightly scattered The chaotic layer is conformal to the rough surface of the slightly scattered chaotic layer and has the rough surface, and is composed of a high-reflectivity metal. 7. The pixel according to item 6 of the patent application scope, wherein the slightly scattered layer package Page 17 200416446 6. The scope of patent application includes: a conductive layer on the substrate; and an insulating layer on the conductive layer with the nano-level rough surface. 8. The day element of claim 7 in the scope of the patent application, wherein the conductive layer is composed of I T 0 or I Z 0. 9. The pixel according to item 7 of the application, wherein the insulating layer is composed of silicon nitride, silicon oxide, or silicon oxynitride. 10. The pixel according to item 6 of the scope of the patent application, wherein the slightly scattered layer includes at least an insulating layer having the nano-level rough surface. 11. The pixel according to item 10 of the patent application scope, wherein the insulating layer is composed of amorphous silicon, polycrystalline silicon, silicon nitride, silicon oxide, or silicon oxynitride. 12. The pixel according to item 6 of the patent application scope, wherein the micro-scattered layer includes at least a seed layer and an insulating layer having the nano-level rough surface. 13. The pixel according to item 12 of the scope of patent application, wherein the insulating layer is subjected to a high-temperature sintering growth process. 1 4. The daily element of item 6 of the scope of application for a patent, wherein the high reflectivity metal is a motto, silver or a Shao alloy. 15. The pixel according to item 1 of the scope of patent application, wherein the second part is a plurality of reflecting plates having the nano-scale rough surface. 16. The pixel according to item 15 of the scope of patent application, wherein the plurality of reflecting plates are curved structures. 1 7. The pixel according to item 1 of the patent application scope, wherein the first part is a gate electrode. 1 8. The pixel according to item 1 of the patent application scope, wherein the switching element is Page 18 200416446 6. Scope of patent application A thin film transistor. 19. The pixel according to item 1 of the patent application scope, wherein the third structure includes: a color filter; a scattering film sandwiched between the color filter and the liquid crystal layer; and a polarizing film, On this color filter. 20. The pixel according to item 1 of the patent application scope, wherein the first structure is formed by an inorganic thin film process. 2 1. The daylight element as described in the first item of the patent application scope, wherein the first structure further includes a light-transmitting area, the light-transmitting area has a first area, the second part has a second area, and the first area The second area ratio is from 10% to 400% ° 2 2. — A process for manufacturing a horizontal electric field thin film transistor liquid crystal display pixel, including the following steps: forming a nano-scale rough surface on a substrate A first structure; partially etching the first structure to form a first portion and a second portion; forming a second structure on the first portion to be used as a switching element; forming on the second structure and the second portion A liquid crystal layer; and forming a third structure on the liquid crystal layer. 2 3. The process of claim 22 in the scope of patent application, wherein the step of forming the first structure includes: forming a slightly scattered layer on the substrate; and forming a reflective layer with a high reflectance on the insulating layer . Page 19, 200416446 VI. Application for patent scope 2 4. The process of applying for patent scope No. 23, wherein the step of forming the slightly scattered layer includes: forming a conductive layer on the substrate; and depositing on the conductive layer An insulating layer is formed to form the nano-scale rough surface. 25. The process of claim 24, wherein the step of forming the conductive layer includes forming ITO or IZ0. 26. The process according to item 24 of the scope of patent application, wherein the step of forming the insulating layer includes forming by nitriding, oxidizing stone or oxynitriding. 2 7. The process according to item 23 of the scope of patent application, wherein the step of forming the slightly scattered layer includes at least forming an insulating layer having the nano-level rough surface. 28. The process according to item 27 of the scope of patent application, wherein the step of forming the insulating layer includes forming from amorphous silicon, polycrystalline silicon, silicon nitride, silicon oxide, or oxynitride. 29. The process according to item 23 of the scope of patent application, wherein the step of forming the finely divided 脔 L layer includes at least forming a seed layer and an insulating layer having the nano-level rough surface. 30. The process of claim 29, wherein the step of forming the insulating layer includes a high-temperature sintering process. 31. The process of claim 23, wherein the step of forming the reflective layer includes using aluminum, silver, or an aluminum alloy. 32. The process of claim 22, wherein the step of forming the first part includes forming a gate electrode. 3 3. If the process of item 22 of the scope of patent application, which forms the second Page 20 200416446 6. The scope of the patent application part of the steps includes forming a plurality of reflective plates with the nano-scale rough surface. 3 4. The process according to item 22 of the scope of patent application, wherein the step of forming the second part includes forming a plurality of curved reflective plates having the nano-level rough surface. 35. The process of claim 22 in the scope of patent application, wherein the step of forming the first structure includes forming using an inorganic thin film process. 36. The process of claim 22 in the scope of patent application, wherein the step of forming and forming the switching element includes forming a thin film transistor. 37. The process according to item 22 of the scope of patent application, wherein the step of forming the third structure includes at least: forming a scattering film; forming a color filter on the scattering film; and forming on the color filter. A polarizing film. 38. A transverse electric field liquid crystal display | § The base plate 5 of the day element includes a substrate; a thin film transistor on the substrate; a plurality of reflective plates, each of which includes: a slightly scattered layer having One nanometer rough surface; A reflective layer on the micro-scattered layer conforming to the rough surface of the micro-scattered layer to have the rough surface, the reflective layer and the gate of the thin film transistor are the same metal; a protective layer covering the A plurality of reflective plates; and a metal layer on the protective layer, and passing through the protective layer to overlap one of the plurality of reflective plates. Page 21 200416446 6. Application for patent scope 39. For example, the bottom plate for scope 38 of the patent application scope, wherein the rough mask has a voltage drop range between 5nm and 50nm. 40. The base plate according to item 38 of the scope of the patent application, wherein the rough mask has a volt period ranging from 10 nm to 500 nm. 41. The bottom plate according to item 38 of the scope of patent application, wherein the slightly scattered layer includes: a conductive layer; and an insulating layer having the nano-level rough surface on the conductive layer. 4 2. The base plate according to item 41 of the patent application scope, wherein the conductive layer is composed of IT0 or IZ0. 43. The baseplate according to item 41 of the scope of patent application, wherein the insulating layer is composed of silicon nitride, silicon oxide, or silicon oxynitride. 4 4. The bottom plate according to item 38 of the scope of patent application, wherein the slightly scattered layer includes at least an insulating layer having the nano-scale rough seam surface. 4 5. The base plate according to item 44 of the patent application scope, wherein the insulating layer is composed of amorphous silicon, polycrystalline silicon, silicon nitride, silicon oxide, or silicon oxynitride. 46. The bottom plate according to item 38 of the scope of patent application, wherein the slightly scattered layer includes at least a seed layer and an insulating layer having the nano-level rough surface. 47. The base plate according to item 46 of the patent application scope, wherein the insulating layer is subjected to a high-temperature sintering growth process. 48. The bottom plate according to item 38 of the scope of patent application, wherein the slightly scattered layer is formed by an inorganic thin film process. 49. The base plate according to item 38 of the scope of patent application, wherein the reflective layer is made of a high reflectivity metal. Page 22 200416446 VI. Application scope of patent 50. For the base plate of item 38 of the scope of patent application, wherein the thin film transistor includes NMOS transistor. 51. The substrate according to item 38 of the scope of patent application, wherein the thin film transistor comprises a PMOS transistor. 52. The substrate according to item 38 of the scope of patent application, wherein the thin film transistor includes a CMOS transistor. 53. As for the bottom plate of the 38th patent application scope, it further includes a light-transmitting area having a first area, and the plurality of reflective plates having a second area, and the ratio of the first area to the second area is 1 0% to 4 0%. Page 23