Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Patent
1997-06-23
1999-12-07
Luu, Matthew
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
345 92, G09G 336
Patent
active
059991550
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device that uses a liquid crystal display element, as well as a method of manufacturing an electronic apparatus and display device which uses such a liquid crystal display element.
2. Description of Related Art
Recently, it has become desirable to reduce the cost of liquid crystal devices used for personal computers. Therefore, planning for the increased manufacturing yield resulting from this cost reduction has become an important technological issue. Preventing the panel pixel defects ("dot defects") and shortening the manufacturing process are also effective to increase manufacturing yield.
For example, Japanese Laid-Open Patent No. 4-155316 discloses a method of manufacturing a liquid crystal device. However, in this conventional method, the source electrode and the pixel electrode are on the same layer, and a protective insulation film is not interposed therebetween. Therefore, the problem arises that pixel defects tend to be generated due to shorts between the source electrode and the pixel electrode. The generation of pixel defects decreases yield and increases product cost.
In Japanese Laid-Open Patent No. 3-1648, the source electrode and the pixel electrode are not on the same layer, and a protective insulation film is interposed between them. The source electrode and the pixel electrode is connected through a contact hole. Therefore, in the prior art, any pixel defect due to shorts between the source electrode and the pixel electrode may not be easily generated. However, in the prior art, since a protective insulation is formed between the source electrode and the pixel electrode, it is necessary to form a contact hole connecting the source electrode and the pixel electrode, which increases the number of process steps. Furthermore, if the quality of the contact hole is poor, a pixel gap is formed, which decreases yield and increases product cost.
Thus, the conventional methods described above do not solve the technological problems such as increasing yield and reducing product cost.
DISCLOSURE OF INVENTION
An object of the invention is to solve the technological problems described above, and improve the contact region between the source electrode and the pixel electrode. Therefore, it is an object of the invention to provide a display device, an electronic apparatus and a method of manufacturing an electronic apparatus and display device to increase yield and reduce product cost.
In order to solve the above problems, the present invention relates to a display device including a pixel electrode for driving the display element and a switching element connected to the pixel electrode through a source electrode. A capacitance ratio RA.sub.C1 is set such that the following relationship is established:
C.sub.X is the parasitic capacitance between the pixel electrode and the source electrode when a bad contact exists between the pixel electrode;
C.sub.0MAX is the maximum value of the pixel capacitance held by the pixel electrode when said the contact does not exist;
V.sub.LCMIN is the voltage when the transmissivity at the pixel position is a minimum; and
V.sub.LCMAX is the voltage when the transmissivity is a maximum.
In accordance with the invention, when a parasitic capacitance C.sub.X has occurred because of a bad contact, for example, in a normally-white display device, the pixel defects can be changed into a display tone shift, and it becomes possible to eliminate the pixel defects apparently. For example, the voltage of the pixel where the transmissivity is minimum T.sub.MIN "black display pixel" can be made to be greater than the voltage V.sub.LCMAX during maximum transmissivity. Consequently, this pixel becomes gray rather than white. If the display is gray, the invention makes it possible to eliminate the pixel defects apparently.
The capacitance ratio can be set by controlling various parameters, such as the overlapping surface area between the source electrode and the pixel electrode, the thi
REFERENCES:
patent: 5635949 (1997-06-01), Shiratsuki et al.
Luu Matthew
Seiko Epson Corporation
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