Patent
1985-12-04
1987-08-18
Corbin, John K.
357 237, H01L 2978, G02F 113
Patent
active
046872981
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a liquid crystal display device, which is used for displaying images, for instance, and has a plurality of display electrodes provided in a liquid crystal cell and selectively driven for display by thin film transistors.
PRIOR ART
FIG. 1 shows a prior art liquid crystal display device structure of the conventional type. The device comprises a pair of glass or like transparent substrates 11 and 12 facing each other and spaced apart by a spacer 13 provided therebetween along the edges. Liquid crystal 14 is sealed between substrates 11 and 12. Substrates 11 and 12, spacer 13 and liquid crystal 14 constitute a liquid crystal cell. Formed on the inner surface of substrate 11, for instance, are a plurality of display electrodes 15 constituted by a transparent conductive film. Thin film transistors 16 are formed contiguous to display electrodes 15 with their drains connected thereto and serve as switching elements. Common, electrode 17 is formed on the entire inner surface of the other transparent substrate 12 and faces display electrodes 15.
Display electrodes 15 may serve as picture element electrodes. They are square in shape and are arranged in a closely spaced-apart relation to one another, as shown in FIG. 2. More specifically, they are arranged in rows and columns on transparent substrate 11. Gate buses 18 are formed near and along the individual rows of display electrodes 15. Source buses 19 are formed near and along the individual columns of display electrodes 15. Thin film transistors 16 noted above are formed at the intersections of gate and source buses 18 and 19. More specifically, each thin film transistor 16 is formed with its gate connected to associated gate bus 18, its source connected to associated source bus 19 and its drain connected to corresponding display electrode 15.
In operation, a voltage is applied between a selected one of gate buses 18 and a selected one of source buses 19. Corresponding thin film transistor 16 is turned on as a result, whereby charge is stored on display electrode 15 connected to the drain of this "on" thin film transistor 16. A voltage is applied across a portion of liquid crystal 14 that is found between this display electrode and common electrode 17. This display electrode alone, is thus rendered transparent or opaque. Only selected display electrodes are rendered transparent or opaque in this way, whereby a corresponding display image is formed. Usually, a polarizer (not shown) is incorporated to render selected display electrodes transparent or opaque.
Thin film transistor 16 usually has a structure as shown in FIGS. 3 and 4. Referring to the Figures, display electrodes 15 and source buses 19 are formed from a transparent conductive film, e.g., an ITO film, which is formed on transparent substrate 11. Semiconductor layers 21 of amorphous silicon or the like are formed such that each of them strides portions of corresponding display electrode 15 and source bus 19 which extend parallel to and are closely spaced apart from each other. Gate insulating film 22 of silicon nitride or the like is formed on semiconductor layers 21. Gate electrodes 23 are formed on gate insulating film 22 such that they overlie portions of display electrodes 15 and source buses 19 via the semiconductor layers 21. The gate electrodes 23 are each connected at one ends to the corresponding gate buses 18. Portions of the display electrodes 15 and source bus 19 facing each gate electrode 23 serve as drain and source electrodes 15a and 19a, respectively. Each thin film transistor 16 is constituted by corresponding electrodes 15a and 19a, semiconductor layer 21, gate insulating film 22 and gate electrode 23. Gate electrodes 23 and gate buses 18 are formed at a time from aluminum, for instance.
This example of liquid crystal device is used for color display and has red, green and blue filters 1R, 1G and 1B provided on the side of transparent substrate 12. Filters 1R, 1G and 1B each face a corresponding display electrode 15. These color filter
REFERENCES:
patent: 4172983 (1979-10-01), McLennan
patent: 4291326 (1981-09-01), Higuchi et al.
patent: 4582395 (1986-04-01), Morozumi
Aoki Shigeo
Miyake Katsumi
Okamoto Kotaro
Ugai Yasuhiro
Corbin John K.
Hosiden Electronics Ltd.
Lewis David
LandOfFree
Forming an opaque metal layer in a liquid crystal display does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Forming an opaque metal layer in a liquid crystal display, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Forming an opaque metal layer in a liquid crystal display will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1114187