JP2003172948A - Liquid crystal display unit and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve unevenness and moire problems of display due to a reflective electrode uneven shape of a liquid crystal display unit. <P>SOLUTION: A photomask characterized by that the area of a photomask opening part in an area where wires or electrodes having a high reflection factor than glass are arranged below an acryl-based resin layer in a pixel is 50 to 95% of the area of a photomask opening part where neither wires nor electrodes are arranged is used to form an uneven shape of the acryl-based resin layer of an array substrate by photolithography and then a reflection type liquid crystal display unit can be obtained which has neither unevenness nor moire of display and has uniform display characteristics. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective liquid crystal display device.

[0002]

2. Description of the Related Art Color mobile phones and PDAs (Personal Dig
Due to the rapid rise of mobile devices such as ital Assistant), the demand for reflective liquid crystal display devices featuring low power consumption is greatly expanding. In a liquid crystal display device having a reflective electrode in a liquid crystal cell, in order to maintain the uniformity of a display image, it is important to form the uneven shape of the reflective electrode at random so as to have no periodicity within a pixel.

FIG. 1 shows a thin film transistor (TFT) in a conventional reflective liquid crystal display device and a method of manufacturing the same.
ansistor; hereinafter abbreviated as TFT. ) A plan view of the array substrate after formation, FIG. 2 is a plan view of the array substrate immediately after the concavo-convex is formed on the array substrate of FIG. 1 by an acrylic resin, and a reflective electrode is formed thereon, and FIG. 3 is A of FIG. -B is a cross-sectional structural view showing a cross-section, FIG. 4 is a cross-sectional view taken along line AB of FIG. 1 after the acrylic resin layer is formed on the array substrate, and FIG. 5 is a cross-section taken along line AB of FIG. 6A is a cross-sectional view, and FIG. 6A is a view showing a region of a reflective electrode of one pixel of a photomask used when forming irregularities on an acrylic resin by photolithography.
FIG. 6B is a diagram showing a surface shape of a region of the reflective electrode of one pixel of the acrylic resin immediately after the unevenness is formed by photolithography using a photomask on the acrylic resin.

In FIG. 1, FIG. 2, FIG. 3, FIG.
1 is a glass substrate, 2a is scanning wiring, 2b is common wiring, 3
Is an interlayer insulating layer, 4 is a channel layer, 5a is signal wiring, 5b
Is a drain electrode, 6 is an acrylic resin layer having irregularities formed by photolithography, 7 is a reflective electrode, and 8 is a contact hole for electrically connecting the reflective electrode and the drain electrode 5b.

The area within the broken line in FIG. 6B shows that the scanning wiring, the common wiring, the signal wiring, or the drain electrode is arranged under the acrylic resin. The array substrate of a normal reflection type liquid crystal display device is formed by repeating film formation, photolithography and etching on the glass substrate 1 to form the scanning wiring 2a and the common wiring 2
By forming b, the interlayer insulating film 3, the channel layer 4, the signal wiring 5a, and the drain electrode 5b, the structure shown in FIG. 3 is formed.

After that, an acrylic resin is applied to the substrate of FIG. 3 to form concavities and convexities on the acrylic resin layer by photolithography, and at the same time, a contact hole 8 is formed to form the structure shown in FIG.

Further, as shown in FIG. 5, a reflective electrode 7 is formed on the acrylic resin layer. Usually, in order to maintain uniformity in display, the openings of a photomask used in photolithography have the same individual shape and are randomly arranged within a pixel, as shown in FIG. 6A. However, when a metal such as Al, Ti, Cr, Ta, or Ag or an oxide film of the above metal is used for the scanning wiring, the common wiring, the signal wiring, or the drain electrode, the acrylic resin layer is formed by photolithography using a photomask. When unevenness is formed in 6, the region where the scanning wiring, the common wiring, the signal wiring, or the drain electrode is arranged has a metal having a higher reflectance than that of the glass substrate or its oxide film in the lower layer of the acrylic resin layer. Therefore, during the exposure of the acrylic resin layer in photolithography, the light energy applied to the acrylic resin layer is compared with a region that does not overlap with any of the scan wiring, the common wiring, the signal wiring, and the drain electrode. Since the size becomes relatively large, the randomness of the uneven shape in the pixel is broken, and FIG.
The shape shown in FIG. As a result, regions having different reflectances in the viewing angle direction are present in a pixel at a specific cycle.

[0008]

In the above-described conventional structure, regions having different reflectances in the viewing angle direction are present in a pixel at a specific cycle, which causes display unevenness and moire.

[0009]

Means for Solving the Problems The present invention solves the above-mentioned problems of the prior art. When unevenness is formed in the acrylic resin layer by photolithography, the acrylic resin layer and the underlying layer are arranged on the acrylic resin layer and the underlying layer. Keeping the randomness of the uneven shape in the pixel by making the mask pattern used in the photolithography different in the area where the scanning wiring, the common wiring, the signal wiring, or the drain electrode overlaps With the goal. As a result, it is possible to eliminate the occurrence of display unevenness and moire.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is
A plurality of scanning wirings and a plurality of signal wirings, a switching element provided at an intersection thereof, a plurality of common wirings arranged substantially parallel to the scanning wirings, and an acrylic resin having an uneven shape formed on an upper layer thereof. A liquid crystal display device comprising a resin layer and a pixel electrode having reflectivity formed on the acrylic resin layer, wherein the concavo-convex shape of the acrylic resin layer is formed by a photolithography method using a photomask. Then, when forming the uneven shape of the acrylic resin layer, the scanning wiring in the lower layer of the acrylic resin layer,
The signal wiring, the switching element, the common wiring,
And a region in which none of the drain electrodes of the switching element are arranged, and the scan wiring, the signal wiring, the switching element, the common wiring, and the drain of the switching element under the acrylic resin layer. It is characterized in that a region where any of the electrodes is arranged is formed by using a photomask having a different opening shape of the photomask.

According to a second aspect of the present invention, a plurality of scanning wirings and a plurality of signal wirings, a switching element provided at an intersection thereof, and a plurality of common wirings arranged substantially parallel to the scanning wirings are provided. A method for manufacturing a liquid crystal display device, comprising: an acrylic resin layer having an uneven shape formed thereon; and a reflective pixel electrode formed on the acrylic resin layer. When the uneven shape of the resin layer is formed by a photolithography method using a photomask, the scan wiring, the signal wiring, the switching element, the common wiring, and the drain of the switching element are formed under the acrylic resin layer. A region where neither of the electrodes is arranged, and the scan wiring, the signal wiring, the switching element, and the front layer under the acrylic resin layer. Common wiring, and a region in which one is arranged in the drain electrode of the switching element, and forming using a photomask in which an opening shape is different of the photomask.

According to a third aspect of the present invention, when the concavo-convex shape of the acrylic resin layer is formed by a photolithography method using a photomask, the scan wiring and the signal wiring are provided under the acrylic resin layer. An area of the photomask opening in a region where any one of the switching element, the common wiring, and the drain electrode of the switching element is arranged, a scanning wiring, a signal wiring, and a switching wiring under the acrylic resin layer. A liquid crystal display device is characterized in that a photomask having 50 to 95% of the area of the photomask opening portion in a region where none of the elements, the common wiring, and the drain electrode of the switching element is arranged is used. It is a manufacturing method.

According to a fourth aspect of the present invention, there is provided a liquid crystal display device in which the pixel electrode is made of Al, Al alloy, Ag or Ag alloy.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device in which the pixel electrode is made of Al, Al alloy, Ag or Ag alloy.

Embodiments of the present invention will be described below with reference to the drawings.

Similar to the array substrate of the conventional reflection type liquid crystal display device, the scanning wiring 2a, the common wiring 2b, the interlayer insulating film 3, the channel layer 4 are formed by repeating film formation, photolithography and etching on the glass substrate 1. Signal wiring 5a,
The structure shown in FIG. 3 is formed by forming the drain electrode.

After that, the acrylic resin 6 is applied to the substrate of FIG. 3, and the contact hole 8 is formed at the same time when the unevenness is formed on the acrylic resin layer by photolithography.
The structure shown in FIG. 4 is formed.

Here, FIG. 7A is a view showing a region of a reflective electrode of one pixel of a photomask used in this embodiment when forming irregularities on an acrylic resin by photolithography. FIG. 7B is a diagram showing the surface shape of the region of the reflective electrode of one pixel of the acrylic resin immediately after the unevenness is formed on the acrylic resin by photolithography using a photomask.

As shown in FIG. 7A, the opening of the photomask used in this photolithography is different from the pattern shown in FIG. 6A used in the conventional method.
In the area where the scanning wiring, the common wiring, the signal wiring, or the drain electrode is present in the lower layer of the acrylic resin, which is shown by the broken line in FIG. 7B, the area of the opening is smaller than the area where these are not present. It was reduced to 92%.

When an uneven shape was formed on the acrylic resin by photolithography using this photomask, as shown in FIG. 7B, it was possible to form unevenness having the same individual shape and high randomness. . When a liquid crystal display device was produced using an array substrate in which the reflective electrode 7 was formed on this substrate, it was possible to obtain uniform display characteristics without display unevenness or moire.

When the irregular shape of the acrylic resin layer of the array substrate is formed by photolithography, the photomask used has a wiring or an electrode having a higher reflectance than glass as the lower layer of the acrylic resin layer. The area of each photomask opening in the pixel in the arranged region is 50 compared with the region in which no wiring or electrode is arranged.
By setting the content in the range of% -95%, it was possible to obtain a liquid crystal display device having uniform display characteristics without unevenness and moire on the display.

[0022]

As described above, according to the present invention, it is possible to obtain a liquid crystal display device having uniform display characteristics without unevenness or moire on the display.

[Brief description of drawings]

FIG. 1 is a plan view of an array substrate after forming a thin film transistor.

FIG. 2 is a plan view of the array substrate immediately after the unevenness is formed on the array substrate of FIG. 1 with an acrylic resin and the reflective electrode is formed thereon.

3 is a sectional view of the array substrate of FIG. 1 taken along the line AB.

4 is a cross-sectional view taken along line AB of FIG. 1 after forming an acrylic resin layer on the array substrate.

5 is a sectional view of the array substrate of FIG. 2 taken along the line AB.

FIG. 6 is a view showing a photomask used for forming concavities and convexities on an acrylic resin by photolithography, and an acrylic resin layer immediately after the concavities and convexities are formed on the acrylic resin by photolithography. The figure which shows the surface shape of the area | region of the reflective electrode of 1 pixel.

7A and 7B are a photomask used for forming an uneven shape by photolithography on an acrylic resin layer in an embodiment of the present invention, and immediately after forming unevenness by photolithography using this photomask. Showing the surface shape of the reflective electrode region of one pixel of the acrylic resin layer of FIG.

[Explanation of symbols]

1 glass substrate 2a scanning wiring 2b common wiring 3 Interlayer insulation film 4 channel layers 5a Signal wiring 5b drain electrode 6 Acrylic resin layer 7 Reflective electrode 8 contact holes 9 Conventional photomask opening 10 Photomask opening in the present invention

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/1343 G02F 1/1343 G09F 9/30 339 G09F 9/30 339Z 9/35 9/35 F term ( Reference) 2H042 BA03 BA12 BA20 DA02 DA04 DA11 2H088 FA19 FA30 HA04 HA14 MA04 2H091 FA16Y FB08 GA07 LA18 2H092 HA05 JA24 JB56 MA14 MA16 NA01 PA12 5C094 AA03 BA03 BA43 CA19 EA04 ED11 FA01 FA04 FB15 GB10 HA08

Claims (5)

[Claims] 1. A plurality of scanning wirings and a plurality of signal wirings, a switching element provided at an intersection thereof, a plurality of common wirings arranged substantially parallel to the scanning wirings, and an unevenness formed in an upper layer thereof. An acrylic resin layer having a shape, and a pixel electrode having reflectivity formed on the acrylic resin layer are provided, and the uneven shape of the acrylic resin layer is formed by a photolithography method using a photomask. A liquid crystal display device, wherein when forming the concavo-convex shape of the acrylic resin layer, the scanning wiring, the signal wiring, the switching element, the common wiring, and the switching element are formed under the acrylic resin layer. Of the drain electrode, the scan wiring, the signal wiring, and the switching element under the acrylic resin layer. , The common line, and, a liquid crystal display device, characterized in that the one of the drain electrodes of the switching elements are arranged region opening shape of the photomask is formed by using a different photomask. 2. A plurality of scanning wirings and a plurality of signal wirings,
A switching element provided at the intersection, a plurality of common wirings arranged substantially parallel to the scanning wirings, an acrylic resin layer having an uneven shape formed in an upper layer thereof, and an acrylic resin layer on the acrylic resin layer. A method of manufacturing a liquid crystal display device comprising a formed pixel electrode having reflectivity, wherein when the uneven shape of the acrylic resin layer is formed by a photolithography method using a photomask, the acrylic resin layer An area in which none of the scanning wiring, the signal wiring, the switching element, the common wiring, and the drain electrode of the switching element is arranged in a lower layer, and the scanning wiring in the lower layer of the acrylic resin layer, the A region where any one of the signal wiring, the switching element, the common wiring, and the drain electrode of the switching element is arranged. Preparative method of manufacturing a liquid crystal display device in which the opening shape of the photomask, and forming with different photomasks. 3. The scan wiring, the signal wiring, the switching element, the common wiring, which is below the acrylic resin layer, when the uneven shape of the acrylic resin layer is formed by a photolithography method using a photomask. and,
The area of the photomask opening in the region where any of the drain electrodes of the switching element is arranged is defined as the scanning wiring, the signal wiring, the switching element, the common wiring, and the switching element in the lower layer of the acrylic resin layer. 3. The method of manufacturing a liquid crystal display device according to claim 2, wherein a photomask having 50 to 95% of the area of the photomask opening in a region where none of the drain electrodes is arranged is used. 4. The pixel electrode is made of Al, Al alloy or Ag.
The liquid crystal display device according to claim 1, which is also made of Ag alloy. 5. The pixel electrode is made of Al, Al alloy or Ag.
3. The method for manufacturing a liquid crystal display device according to claim 2, which is made of Ag alloy.