JP2007024965A - Manufacturing method of liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a liquid crystal display capable of reducing the number of manufacturing steps and a manufacturing cost. <P>SOLUTION: The manufacturing method of the liquid crystal display 1 wherein a liquid crystal layer 5 is held between a pair of substrates 3 and 4 and which is provided with a reflection region A1 and a transmission region A2 whose gap between the pair of substrates 3 and 4 is larger than that of the reflection region A1 includes a step for forming a switching element 7 on an insulating substrate GL1, a step for film-depositing a photosensitive resin film 12 on the insulating substrate GL1 so as to cover the switching element 7, a step for exposing the photosensitive resin film 12 by using a photo mask M and a step for developing the exposed photosensitive resin film 12. In this method, an aperture part 12H penetrating the photosensitive resin film 12 on the switching element 7, a reflection part 3A having an asperity 12A on the surface of the photosensitive resin film 12 in the reflection region A1 and a transmission part 3B forming a step difference G3 from the reflection part 3A in the transmission region A2 are simultaneously formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly to a method for manufacturing a transflective liquid crystal display device having a reflective region and a transmissive region.

  The liquid crystal display device includes a liquid crystal display panel including an array substrate, a counter substrate facing the array substrate, and a liquid crystal layer held as a light modulation layer between the pair of substrates. Recently, a liquid crystal display device having a transflective liquid crystal display panel has been developed for energy saving and the like. The transflective liquid crystal display panel includes an effective display unit configured by matrix display pixels, and the effective display unit includes a reflective region and a transmissive region.

  In general, the gap between the array substrate and the counter substrate in the transmissive region is set to be larger than the gap in the reflective region. For example, a photosensitive resin layer for forming a step is disposed on the array substrate side. . In order not to reduce the aperture ratio of the transmissive region, the switching element is disposed in the reflective region and is covered with the photosensitive resin layer. The switching element is connected to the reflective electrode disposed in the reflective region on the photosensitive resin layer through the contact hole penetrating the photosensitive resin layer and electrically connected to the transmissive electrode disposed in the transmissive region. Yes.

Conventionally, in a reflection type liquid crystal display device, as a method for manufacturing a liquid crystal display device, a concave and convex pattern is formed on the surface of a photosensitive resin layer disposed on a switching element and a contact hole penetrating to the switching element is simultaneously formed. The technique described in Document 1 is known.
JP 2002-6774 A

  However, in the transflective liquid crystal display device, the patterning process of the photosensitive resin layer has not been established, and it is necessary to prepare a plurality of photomasks and perform a plurality of exposures after forming the photosensitive resin film. there were. For this reason, it has been difficult to reduce the number of manufacturing steps and the manufacturing cost.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a method of manufacturing a liquid crystal display device capable of reducing the number of manufacturing steps and manufacturing costs.

  According to a first aspect of the present invention, there is provided a method for manufacturing a liquid crystal display device, comprising: a reflection region; and a transmission region in which a gap between the pair of substrates is larger than the reflection region. A method of manufacturing a liquid crystal display device, the step of forming a switching element on an insulating substrate, the step of forming a photosensitive resin film on the insulating substrate so as to cover the switching element, and a photomask Using the step of exposing the photosensitive resin film and the step of developing the exposed photosensitive resin film, in the opening that penetrates the photosensitive resin film on the switching element, in the reflective region A reflective part having irregularities on the surface of the photosensitive resin film and a transmissive part that forms a step with the reflective part in the transmissive region are simultaneously formed.

  According to a second aspect of the present invention, there is provided a method for manufacturing a liquid crystal display device, comprising: a liquid crystal layer sandwiched between a pair of substrates; a reflective region; and a transmissive region in which a gap between the pair of substrates is larger than the reflective region. A method of manufacturing a liquid crystal display device, the step of forming a switching element on an insulating substrate, the step of forming a photosensitive resin film on the insulating substrate so as to cover the switching element, and a photomask Using the step of exposing the photosensitive resin film and the step of developing the exposed photosensitive resin film, the opening penetrating the photosensitive resin film on the switching element, and the reflection At the same time as forming a reflective part having irregularities on the surface of the photosensitive resin film in the region, the photosensitive resin film in the transmissive region is removed to form the transmissive part.

  According to the present invention, a method for manufacturing a liquid crystal display device capable of reducing the number of manufacturing steps and manufacturing cost can be provided.

  A display device according to an embodiment of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the liquid crystal display device includes a liquid crystal display panel 1 having a substantially rectangular flat plate shape. The liquid crystal display panel 1 includes a pair of substrates, that is, an array substrate 3 and a counter substrate 4, and a liquid crystal layer 5 held as a light modulation layer between the pair of substrates. The liquid crystal display panel 1 includes a substantially rectangular effective display unit 6 for displaying an image. The effective display unit 6 includes a plurality of display pixels PX arranged in a matrix, a plurality of signal supply wirings for supplying a drive signal to each display pixel PX, and the like.

  The array substrate 3 is, for example, a plurality of scanning lines Y (1, 2, 3,...) Extending along the row direction (X direction) of the display pixels PX as signal supply wirings arranged in the effective display unit 6. m) and a plurality of signal lines X (1, 2, 3,..., n) extending along the column direction (Y direction) of the display pixels PX.

  Further, the array substrate 3 includes the switching element 7 and the storage capacitor element 13 which are arranged for each display pixel PX in the vicinity of the intersection of the scanning line Y and the signal line X in addition to the signal supply lines in the effective display unit 6. , And a pixel electrode 8 connected to the switching element 7.

  The liquid crystal display panel 1 includes a first connection portion 31 and a second connection portion 32 that are disposed on the outer peripheral portion 10 located outside the effective display portion 6. The first connection unit 31 can be connected to the drive IC 11 that functions as a signal supply source that supplies a drive signal to the signal supply wiring. The 2nd connection part 32 is connectable with the flexible wiring board FPC which functions as a signal supply source. In the example shown in FIG. 1, the first connection portion 31 and the second connection portion 32 are disposed on the extending portion 10 </ b> A of the array substrate 3 that extends outward from the end portion 4 </ b> A of the counter substrate 4. . The drive IC 11 and the first connection portion 31 are electrically and mechanically connected through, for example, an anisotropic conductive film.

  The driving IC 11 includes a signal line driving unit 11X that supplies a driving signal to the signal line X and a scanning line driving unit 11Y that supplies a driving signal to the scanning line Y. The scanning line driving unit 11Y is electrically connected to each scanning line Y (1, 2, 3,...) Via the connection wiring WY. That is, the drive signal output from the scanning line driving unit 11Y is supplied to each corresponding scanning line Y (1, 2, 3,...) Via each connection wiring WY. The switching elements 7 included in each display pixel PX in each row are on / off controlled based on the scanning signal supplied from the corresponding scanning line Y.

  Further, the signal line driver 11X is electrically connected to each signal line X (1, 2, 3,...) Via the connection wiring WX. That is, the drive signal output from the signal line driver 11X is supplied to each corresponding signal line X (1, 2, 3,...) Via each connection wiring WX. The switching element 7 included in each display pixel PX of each column writes the video signal supplied from the corresponding signal line X to the pixel electrode 8 at the timing when it is turned on.

  As shown in FIG. 2, each display pixel PX has a reflection area A1 and a transmission area A2. In the reflection area A1, a gap G1 is formed between the array substrate 3 and the counter substrate 4, and in the transmission area A2, a gap G2 is formed between the array substrate 3 and the counter substrate 4. The gap G2 is larger than the gap G1, for example, G2 is approximately twice G1.

  In each display pixel PX, the array substrate 3 includes a reflective portion 3A and a transmissive portion 3B corresponding to the reflective region A1 and the transmissive region A2 of the liquid crystal display panel 1, respectively. In the reflecting portion 3A, various wirings are arranged on the transparent insulating substrate GL1 of the array substrate 3 in addition to the switching element 7 and the storage capacitor element 13. The switching element 7 is composed of, for example, a thin film transistor (TFT).

  The gate electrode 7G of the switching element 7 is electrically connected to the corresponding scanning line Y (or formed integrally with the scanning line). On the gate electrode 7G, the gate insulating film 14 is disposed over the reflective portion 3A and the transmissive portion 3B, and the semiconductor layer 7A is disposed on the gate electrode 7G via the gate insulating film 14. The source electrode 7S of the switching element 7 is in contact with the semiconductor layer 7A and is electrically connected to the corresponding signal line X (or formed integrally with the signal line). The drain electrode 7D of the switching element 7 is in contact with the semiconductor layer 7A. The storage capacitor element 13 has an electrode formed in the same layer as the gate electrode 7 </ b> G of the switching element 7, and shares the drain electrode 7 </ b> D of the switching element 7 with the switching element 7.

  In the reflective portion 3 </ b> A, the organic insulating film 12 is disposed on the switching element 7 and the storage capacitor element 13. The organic insulating film 12 is made of a photosensitive resin and has a contact hole 12H penetrating on the drain electrode 7D. The organic insulating film 12 has irregularities on its surface 12A. Further, the organic insulating film 12 forms a step G3 corresponding to a substantial difference between the gaps G1 and G2 between the reflective portion 3A and the transmissive portion 3B.

  The pixel electrode 8 includes a reflective electrode 8A disposed along the unevenness of the organic insulating film 12 in the reflective portion 3A, and a transmissive electrode 8B disposed on the reflective electrode 8A and covering the reflective portion 3A and the transmissive portion 3B. ing. The reflective electrode 8A is made of a light reflective metal such as aluminum, and reflects light incident on the reflective region A1 from the counter substrate 4 side to the counter substrate 4 side. The transmissive electrode is formed of a light transmissive metal such as ITO (Indium Tin Oxide). The pixel electrode 8 is in contact with the drain electrode 7D of the switching element 7 through the contact hole 12H.

  The counter substrate 4 includes a counter electrode 9 and the like common to all the display pixels PX in the effective display section 6. The array substrate 3 and the counter substrate 4 are disposed with the pixel electrodes 8 and the counter electrodes 9 of all the display pixels PX facing each other. At this time, the gap G2 in the transmissive region A2 is larger than the gap G1 in the reflective region A1 due to the step G3 between the upper surface of the reflective portion 3A of the array substrate 3 and the upper surface of the transmissive portion 3B.

  In the color display type liquid crystal display device, the liquid crystal display panel 1 includes a plurality of types of display pixels, for example, a red pixel that displays red (R), a green pixel that displays green (G), and a blue that displays blue (B). Has pixels. That is, the red pixel includes a red color filter that transmits light having a red main wavelength. The green pixel includes a green color filter that transmits light having a green dominant wavelength. The blue pixel includes a blue color filter that transmits light having a blue main wavelength. These color filters are arranged on the main surface of the array substrate 3 or the counter substrate 4.

  The manufacturing method of said liquid crystal display panel 1 is demonstrated using FIGS. First, the array substrate 3 is manufactured. A transparent insulating substrate GL1 is prepared, and a metal film or an insulating film is repeatedly formed and patterned on the insulating substrate GL1, thereby forming the switching element 7 and the storage capacitor element 13 as shown in FIG. Further, a photosensitive resin film 15 for forming the organic insulating film 12 is formed on the switching element 7 and the storage capacitor element 13.

  Subsequently, as shown in FIG. 4, the photosensitive resin film 15 is exposed using a photomask M. The photomask M has a pattern for forming the reflection portion 3A, the transmission portion 3B, and the contact hole 12H of the array substrate 3. That is, the photomask M has a pattern M1 corresponding to the reflective portion 3A, a pattern M2 corresponding to the transmissive portion 3B, and a pattern M3 corresponding to the contact hole 12H. These patterns M1 to M3 include a light shielding body 17 for adjusting the exposure amount. The light shielding body 17 is, for example, a cylindrical or polygonal column having a diameter of 1.5 μm to 2.5 μm, and is arranged at a pitch of 4 μm to 5 μm. The diameter and pitch of the light shielding body 17 are determined for each pattern according to the required exposure amount. In the example illustrated in FIG. 4, the light shielding body 17 is provided in the pattern M1, and the light shielding body 17 is not disposed in the patterns M2 and M3. However, the present invention is not limited to this example.

  When the photosensitive resin film 15 is exposed using the photomask M as described above, a difference in exposure amount occurs for each pattern. That is, the exposure amount is smaller in the pattern M1 than in the pattern M2 and the pattern M3. In addition, in the pattern M2 and the pattern M3, a substantially equivalent relatively high exposure amount can be obtained.

  Subsequently, as shown in FIG. 5, the exposed photosensitive resin film 15 is developed. That is, when the photosensitive resin film 15 is exposed using the above-described photomask M and then developed under a predetermined developing condition using a predetermined developer, the contact hole 12H and the transmission part 3B are supported. The photosensitive resin film 15 is removed. Further, the photosensitive resin film 15 corresponding to the reflective portion 3A is not removed, and the organic insulating film 12 having irregularities on the surface 12A is formed.

  Subsequently, as shown in FIG. 6, a reflective electrode 8 </ b> A is formed along the unevenness of the reflective portion 3 </ b> A by patterning after depositing a metal such as aluminum on the organic insulating film 12. Further, a transparent metal film such as ITO (Indium Tin Oxide) is formed and then patterned to form a transmissive electrode 8B that contacts the switching element 7 in the contact hole 12H and covers the reflective portion 3A and the transmissive portion 3B. Then, the pixel electrode 8 including the reflective electrode 8A and the transmissive electrode 8B is formed. That is, a step G3 is formed between the upper surface of the reflective portion 3A and the upper surface of the transmissive portion 3B of the array substrate 3.

  Next, the counter substrate 4 is manufactured. A transparent insulating substrate GL2 is prepared. On the insulating substrate GL2, the counter substrate 4 provided with the counter electrode 9 is formed as a metal film formation and patterning.

  Subsequently, as shown in FIG. 2, the array substrate 3 and the counter substrate 4 are arranged so that all the pixel electrodes 8 and the counter electrode 9 face each other, and the liquid crystal layer 5 is interposed between the array substrate 3 and the counter substrate 4. These are pasted together by a seal member in a state in which a space for enclosing them is formed. The liquid crystal layer 5 is formed of a liquid crystal composition sealed in the gap between the array substrate 3 and the counter substrate 4, and the liquid crystal display panel 1 is manufactured.

  As described above, using one photomask M having the pattern M1 for forming the reflective portion 3A, the pattern M2 for forming the transmissive portion 3B, and the pattern M3 for forming the contact hole 12H. By developing after exposing the photosensitive resin film 15, it is possible to simultaneously form the reflective portion 3A, the contact hole 12H, and the transmissive portion 3B by one photolithography process.

  That is, according to the present invention, it is not necessary to use a plurality of photomasks to form the reflective portion 3A, the contact hole 12H, and the transmissive portion 3B, and the number of manufacturing steps can be reduced. The manufacturing cost can be reduced.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. For example, in the above embodiment, as shown in FIG. 2, the step between the transmissive region and the reflective region is formed by removing the photosensitive resin film 15 of the transmissive portion 3B. The conductive resin film 15 may not be completely removed. That is, the size of the step may be set by the difference between the necessary gap in the reflection region and the necessary gap in the transmission region. For this reason, it may be required to form a step smaller than the film thickness at the time of forming the photosensitive resin film.

  In response to such a requirement, the present invention can independently control the exposure amounts of the pattern M1 corresponding to the reflective portion 3A, the pattern M2 corresponding to the transmissive portion 3B, and the pattern M3 corresponding to the contact hole 12H. Since a simple photomask is applied, a contact hole penetrating the photosensitive resin film and a photosensitive resin film are formed by a single photolithography process through one photomask, as in the above-described embodiment. It is possible to simultaneously form a reflective portion having minute irregularities on the surface and a transmissive portion that forms a step having a required size with respect to the reflective portion without penetrating the photosensitive resin film.

  That is, the photomask applied in this case is provided with a light shielding body for adjusting the exposure amount of the pattern M2 corresponding to the transmission part 3B, and the relationship between the exposure amounts of the patterns is as follows: pattern M1> pattern M2> The relationship is as in the pattern M3. As a result, a desired step is formed between the upper surface of the reflective portion 3A and the upper surface of the transmissive portion 3B, and the gap G2 in the transmissive region A2 of each display pixel PX is larger than the gap G1 in the reflective region A1.

  In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a diagram schematically showing a liquid crystal display panel of a liquid crystal display device according to one embodiment of the present invention. FIG. 2 is a diagram schematically showing a cross section of a display pixel of the liquid crystal display panel shown in FIG. 1. The figure explaining the manufacturing method of the array board | substrate of the liquid crystal display panel shown in FIG. The figure explaining the manufacturing method of the array board | substrate of the liquid crystal display panel shown in FIG. The figure explaining the manufacturing method of the array board | substrate of the liquid crystal display panel shown in FIG. The figure explaining the manufacturing method of the array board | substrate of the liquid crystal display panel shown in FIG. Sectional drawing which shows schematically the array substrate of the liquid crystal display device which concerns on other embodiment of this invention.

Explanation of symbols

  PX ... display pixel, Y (1,2, ..., m) ... scanning line, X (1,2, ..., n) ... signal line, 1 ... liquid crystal display panel, 3 ... array substrate, 3A ... reflecting part, 3B DESCRIPTION OF SYMBOLS ... Transmission part, 4 ... Opposite substrate, 5 ... Liquid crystal layer, 6 ... Effective display part, 7 ... Switching element, 7G ... Gate electrode, 7S ... Source electrode, 7D ... Drain electrode, 7A ... Semiconductor layer, 8 ... Pixel electrode, 8A ... Reflective electrode, 8B ... Transparent electrode, 9 ... Counter electrode, 10 ... Outer peripheral part, 10A ... Extended part, 11 ... Drive IC, 11X ... Signal line drive part, 11Y ... Scan line drive part, 12 ... Organic insulation Film: 12H: Contact hole, 13: Retention capacity, 14: Gate insulating film, 15: Photosensitive resin film, 17: Light shielding body, A1: Reflection area, A2: Transmission area, WX, WY: Connection wiring, M: Photo Mask, M1, M2, M3 ... Mask pattern, GL1, GL2 ... Absolute Sex board

Claims (4)

A method of manufacturing a liquid crystal display device, comprising: a liquid crystal layer sandwiched between a pair of substrates; a reflective region; and a transmissive region in which a gap between the pair of substrates is larger than the reflective region,
Forming a switching element on an insulating substrate;
Forming a photosensitive resin film on the insulating substrate so as to cover the switching element;
Exposing the photosensitive resin film using a photomask;
And developing the exposed photosensitive resin film,
An opening that penetrates the photosensitive resin film on the switching element, a reflective portion having irregularities on the surface of the photosensitive resin film in the reflective region, and a transmission that forms a step with the reflective portion in the transmissive region Of manufacturing a liquid crystal display device.   The liquid crystal display device according to claim 1, further comprising a step of forming a pixel electrode that contacts the switching element in the opening and includes a reflective electrode that covers the reflective portion and a transmissive electrode that covers the transmissive portion. Manufacturing method.   The method of manufacturing a liquid crystal display device according to claim 1, wherein the photomask has a pattern that forms the reflective portion, the transmissive portion, and the opening. A method of manufacturing a liquid crystal display device, comprising: a liquid crystal layer sandwiched between a pair of substrates; a reflective region; and a transmissive region in which a gap between the pair of substrates is larger than the reflective region,
Forming a switching element on an insulating substrate;
Forming a photosensitive resin film on the insulating substrate so as to cover the switching element;
Exposing the photosensitive resin film using a photomask;
And developing the exposed photosensitive resin film,
An opening that penetrates the photosensitive resin film on the switching element, and a reflective portion having irregularities on the surface of the photosensitive resin film in the reflective region, and at the same time, the photosensitive resin film in the transmissive region A method for manufacturing a liquid crystal display device, which is removed to form the transmission part.

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