Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1998-05-29
2001-05-15
Parker, Kenneth (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
Reexamination Certificate
active
06233034
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority from the following applications filed with the Korean Industrial Property Office, the disclosures of which are hereby incorporated by reference:
Patent Application No. 97-76720, filed Dec. 29, 1997, entitled “LIQUID CRYSTAL DISPLAY DEVICE”; and
Patent Application No. 98-9243, filed Mar. 18, 1998, entitled “LCD HAVING HIGH TRANSMITTANCE AND HIGH APERTURE RATIO AND METHOD FOR MANUFACTURING THE SAME.”
BACKGROUND OF THE INVENTION
The present invention relates to a display and a method of manufacturing the same. More particularly, the present invention provides a novel liquid crystal display having a relatively high transmittance and a relatively high aperture ratio. The present invention also provides a method of manufacturing the same.
Rapid progress in the device performance of active matrix liquid crystal displays (“LCDs”) has opened a wide range of the applications, such as flat panel television (“TV”) systems, and high-information content monitors for portable computers.
A common type of technology used in these displays is conventional twisted nematic (“TN”) display mode. Conventional TN display mode, however, has intrinsic properties of narrow viewing characteristics and slow response time. Most particularly, TN has slow response time for gray scale operation.
In order to solve these limitations, various techniques used in liquid crystal displays (i.e., LCDs) have been suggested or suggested. As merely an example, techniques such as a multi-domain TN structure, and an optically compensated birefringence (“OCB”) mode that compensates physical characteristics of the liquid crystal molecules have been proposed.
Although the multi-domain structure is often useful in improving the viewing angle, any enhancement of the viewing zone is generally limited. Additionally, an intrinsic property of slow response time still remains unsolved, in part, and processes for forming the multi-domain structure are often complicated and difficult to achieve. In contrast, the OCB mode has typically proved to have better electro-optic performances, including viewing characteristics and response time. The OCB mode, however, may have difficulties in controlling conformation of the liquid crystal molecules for self-compensation structure via a bias voltage.
Other technologies such as an in-plane switching (“IPS”) mode where electrodes for controlling the liquid crystal molecules are formed on the same substrate has been proposed. As an example, M. Oh-e, M. Ohta, S.Aratani, and K. Kondo in “Proceeding of the 15th International Display Research Conference”, p. 577 by Society for Information Display and the intrinsic of Television Engineer of Japan (1995) describe an IPS mode. The display with IPS mode also has numerous limitations. Since these displays often use materials that are opaque, display transmittance often decreases. In some cases, a back light with high intensity light is used, which is undesirable for lower powered portable computing applications, as well as others. Additional limitations include difficulty in manufacturing, which often involves complex planarization processes. These and other limitations are described throughout the present specification.
From the above, it is seen that an improved technique for fabricating an LCD display is highly desirable.
SUMMARY OF THE INVENTION
According to the present invention, a technique including a method and a device for the manufacture of an improved display is provided. In an exemplary embodiment, the invention increases an aperture ratio of the liquid crystal display and the transmittance thereof. In other aspects, the invention improves the topology of the structure of the lower substrate without the need of additional planarization process, which are commonly used in conventional devices.
According to one aspect of the invention, a liquid crystal display is provided. The display includes a variety of elements such as a first substrate and a second substrate, one being disposed opposite the other a first distance apart. Each substrate has an inner surface and an outer surface that is opposite the inner surface. The display also has a liquid crystal layer sandwiched between the inner surfaces of the substrates. The liquid crystal layer has a plurality of liquid crystal molecules. A first electrode is formed on the inner surface of the first substrate and has a first width. A second electrode is formed on the inner surface of the first substrate and has a second width. The second electrode is spaced apart by a second distance from the first electrode. These electrodes align the liquid crystal molecules using an electric field produced between the electrodes. The first and second electrodes are formed of a transparent conductive material (e.g., ITO). The display has the first distance that is greater than the second distance. Preferably, the first and second electrodes each has a width to such a degree that the liquid crystal molecules above the first and second electrodes are substantially aligned by the electric field.
According to another aspect of the invention, a liquid crystal display is provided. The display includes a variety of elements such as a first substrate and a second substrate, one being disposed opposite the other a first distance apart. Each substrate has an inner surface and an outer surface that is opposite the inner surface. The display also has a liquid crystal layer sandwiched between the inner surfaces of the two substrate. The liquid crystal layer has a plurality of liquid crystal molecules. A first electrode is disposed on the inner surface of the first substrate. The first electrode comprises a plurality of strips, each of the strips having a first width, and spaced apart by a second distance from another strip adjacent thereto. A second electrode is also disposed on the first substrate. The second electrode comprises a plurality of strips, each of the strips being disposed between the strips of the first electrode, having a second width, and being spaced apart by a third distance from another strip adjacent thereto, each of the strips of the second electrode being separated from each of the strips of the first electrode adjacent thereto with a fourth distance. An insulating layer is formed between the first and second electrodes. The insulating layer insulates the first electrode and the second electrode each other. The first electrode and the second electrode each is made of a transparent conductor, and the first distance is greater in length than the fourth distance. The second width is smaller than the second distance, and the first width is smaller than the third distance. Preferably, the strips of the second electrode each has a width to such a degree that the liquid crystal molecules overlying the strips of the first electrode and the strips of the second electrode are substantially aligned in the presence of the electric field produced between the strips of the first electrode and the strips of the second electrode, and the first width is smaller than the third distance.
According to a further aspect of the invention, a liquid crystal display is provided. The display includes a variety of elements such as a first substrate and a second substrate, one being disposed opposite the other a first distance apart. Each substrate has an inner surface and an outer surface that is opposite the inner surface. The display also has a liquid crystal layer sandwiched between the inner surfaces of the two substrate. The liquid crystal layer has a plurality of liquid crystal molecules. A first electrode is formed on the inner surface of the first substrate. The first electrode has a squared plate structure. An insulating layer is disposed on the inner surface of the first substrate including the first electrode. A second electrode is disposed on the insulating layer. The second electrode comprises a plurality of strips, the strips each being disposed to overlap with the first electrode and to have a first width and a second distance therebetween, wherei
Choi Woo Ho
Lee Jung Yeal
Lee Seok Lyul
Lee Seung Hee
Hyundai Electronics Industries Co,. Ltd.
Parker Kenneth
Townsend & Townsend & Crew LLP
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