Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2001-12-04
2002-06-11
Dudek, James (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S151000, C349S152000
Reexamination Certificate
active
06404478
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the invention
The present invention relates to a liquid crystal display (LCD). More particularly, it relates to a liquid crystal panel incorporated in an LCD.
2. Description of the Related Art
As known in the art, a liquid crystal display incorporates an LC panel which may typically be made up of two glass plates (front glass and rear glass), a liquid crystal layer disposed between the glass plates, a polarizer, etc. When the LC panel is of the simple matrix type, a number of transparent electrodes are formed on each glass plate. The electrodes on one glass plate may extend horizontally, while the electrodes on the other glass plate may extend vertically. Thus, when the two glass plates are assembled, the mutually perpendicular electrodes provide a great number of intersections each of which serves as a pixel.
To control the LC panel, use may be made of a number of electric devices including a semiconductor chip, voltage-boosting or voltage-regulating capacitors, etc. These devices may individually be mounted on the rear glass plate of the LC panel. For facilitating the mounting operation, the front glass plate may be made smaller than the rear glass plate. With this arrangement, the rear glass plate has a projecting portion that does not overlap any part of the front glass plate. It is possible to mount the above-mentioned devices onto this projecting portion without undergoing any interference with the front glass plate.
In the above LCD, the semiconductor chip may be connected to the capacitors by a wiring pattern formed on the rear glass plate. For improved efficiency of the fabrication process, this wiring pattern and the transparent electrodes on the rear glass plate may be made simultaneously with the use of the same conductive material.
While the prior art LCD is functional, it has the following drawbacks.
As noted above, the chip-capacitor connecting pattern is preferably made of the same material used for making the transparent electrodes on the rear glass plate. In general, a conductive material used for making such transparent electrodes has rather high resistivity. Thus, if the connecting pattern has a long current passage connecting the semiconductor chip and one of the capacitors, the voltage drop along the passage may be unduly large. Unfavorably, this may hinder proper voltage supply to the semiconductor chip from the capacitor.
One way to address the above problem is to arrange the capacitor close to the semiconductor chip, thereby reducing the resistance of the current passage. In this case, the remaining capacitors also need to be disposed near the semiconductor chip, so that they can equally enjoy the advantage of the shortened current passage. In addition, all the capacitors are spaced equidistantly (or substantially equidistantly) from the semiconductor chip (see FIG.
14
), so that the current passages from the respective capacitors to the semiconductor chip have the same resistance (hence the same voltage drop).
With the above arrangements, however, a rather wide region is required on the projecting portion of the rear plate to accommodate all the capacitors arranged in an array (FIG.
14
). Disadvantageously, such a layout leads to an increase in the projection amount L, which in turn may cause an increase in overall size of the product LCD.
SUMMARY OF THE INVENTION
The present invention has been proposed under the circumstances described above. It is, therefore, an object of the present invention to provide an LCD in which a properly high driving voltage can be constantly applied to the control semiconductor chip without rendering the product LCD bulky and heavy.
According to a first aspect of the present invention, a liquid crystal display is provided, which includes: a first transparent plate; a second transparent plate having a projecting portion that avoids facing the first transparent plate; a liquid crystal layer disposed between the first and the second transparent plates; a semiconductor chip mounted on the projecting portion for display control; a first capacitor mounted on the projecting portion; a second capacitor mounted on the projecting portion, the second capacitor being spaced from the chip by a distance which is greater than a distance between the first capacitor and the chip; a first conductive element extending between the first capacitor and the chip for electrical connection; and a second conductive element extending between the second capacitor and the chip for electrical connection. The first and the second conductive elements are equal in resistance.
Preferably, the first conductive element may be a strip having a first width, and the second conductive element may be a strip having a second width greater than the first width.
Preferably, the liquid crystal display may further include a third conductive element for connecting the first capacitor to the chip, wherein the second conductive element is disposed between the first and the third conductive elements.
Preferably, the liquid crystal display of the present invention may further include a third capacitor and a fourth conductive element. The third capacitor is spaced from the chip by a distance equal to the distance between the second capacitor and the chip. The fourth conductive element connects the third capacitor to the chip. The fourth conductive element is connected to both the second and the third capacitors.
Preferably, the semiconductor chip may have a side surface facing the first capacitor. The second and the third capacitors are aligned to each other along an imaginary line extending in parallel to the above side surface of the chip.
Preferably, the liquid crystal display of the present invention may further include a fourth capacitor spaced from the chip by a distance equal to the distance between the first capacitor and the chip. The distance between the first and the fourth capacitors is greater than the distance between the second and the third capacitors.
Preferably, the liquid crystal display of the present invention may further include a transparent electrode pattern formed on the second transparent plate. The first and second conductive elements and the electrode pattern are made of the same conductive material.
According to a second aspect of the present invention, an electric module is provided, which includes a support; a reference device mounted on the support, the reference device being provided with a first connection pad and a second connection pad; a first cooperative device spaced from the reference device by a first distance; a second cooperative device spaced from the reference device by a second distance which is greater than the first distance; a first conductive element for connecting the first cooperative device to the first pad of the reference device, the first conductive element including both a first base end attached to the first pad and a first extension attached to the first cooperative device, the first base end being greater in width than the first extension; and a second conductive element for connecting the second cooperative device to the second pad of the reference device, the second conductive element including both a second base end attached to the second pad and a second extension attached to the second cooperative device, the second base end being smaller in width than the second extension. The first extension is substantially equal in resistance to the second extension.
Preferably, the electric module of the present invention may further include a package for enclosing the first and the second cooperative devices.
Other features and advantages of the present invention will become apparent from the detailed description given below with reference to the accompanying drawings.
REFERENCES:
patent: 4145120 (1979-03-01), Kubota
patent: 5847783 (1998-12-01), Hiramoto et al.
patent: 5870163 (1999-02-01), Watanabe et al.
patent: 6285432 (2001-09-01), Phillips
patent: 033802 (2001-02-01), None
Hayashi Hideki
Ikefuji Yoshihiro
Mochida Hiroo
Nakashima Takayuki
Bednarek Michael D.
Dudek James
Rohm & Co., Ltd.
Shaw Pittman LLP
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