CN2237857Y - Storage capacitor structure of thin-film electric crystal liquid crystal display apparatus - Google Patents

Abstract

The utility model discloses a storage capacitor structure of a thin-film electric crystal liquid crystal displayer which is designed into a grate shape. On one hand the aperture opening ratio of the utility model can be increased, and on the other hand, because the part that the grate-shaped storage capacitor of the thin-film electric crystal liquid crystal displayer is adjacent to scanning lines and signal lines is reduced, the short circuit phenomenon can be effectively reduced each other, and the delaying capacitor effect can be reduced.

Description

A kind of storage capacitor structure of membrane transistor LCD

The utility model relates to a kind of storage capacitor structure of membrane transistor LCD, first electrode design that relates in particular to the storage capacitors of membrane transistor LCD becomes palisade, and be positioned at the middle body of pixel capacitors, respectively apart from pixel capacitors Ge Yue 1/4 place up and down, the longitudinal component of this palisade storage capacitors is positioned at the top plate shading matrix, can effectively reduce short circuit phenomenon and reduce to postpone capacity effect.

Membrane transistor (hereinafter to be referred as TFT) has been widely applied on LCD, sweep time each time (about 63.5 μ s) signal transmit and be stored in the liquid crystal capacitance through TFT, (about 16.7ms) update signal when next time scanning.But the capacitance of general present liquid crystal little (about 0.3pf), the signal charge that can store is limited, causes equivalent voltage decline in the loss of each sweep spacing electric charge, makes film flicker; Membrane transistor has the formed coupling capacitance Cgs in overlapping region of a gate and source electrode inevitably in addition, and it can cause the voltage drop Δ Vgs (as figure one) on the pixel capacitors $\mathrm{\ΔVgs}=\frac{\mathrm{Cgs}}{\mathrm{Cls}+\mathrm{Cgs}}\·\mathrm{Vg}$

For reducing above-mentioned influence, each manufacturers design goes out the storage capacitors Cs structure in parallel with liquid crystal capacitance to address the above problem, and can increase the storage capacity of signal charge so on the one hand, can reduce the influence of coupling capacitance on the other hand, and this moment, voltage was reduced to $\mathrm{\ΔVgs}=\frac{\mathrm{Cgs}}{\mathrm{Cls}+\mathrm{Cs}+\mathrm{Cgs}}\·\mathrm{Vg}$

Storage capacitors production method well known in the prior art has three kinds, be described below respectively: be the storage capacitors of first kind of known membrane transistor LCD shown in Fig. 2 (a), the composition of storage capacitors 14 is made of the metal electrode, gate insulation layer 12, ITO electrode 13 threes that form simultaneously with gate 11, figure two (b) is its vertical view, and its oblique line partly is the metal electrode of storage capacitors.The metal electrode of storage capacitors reduces the aperture opening ratio of membrane transistor LCD across crossing pixel capacitors as seen from the figure.

Fig. 3 (a) is depicted as the storage capacitors of second kind of known membrane transistor LCD, its storage capacitors 14 utilizes the extension of gate 11 and gate insulation layer 12, ITO electrode 13 to form jointly, though its storage capacitors is positioned at upper strata shading matrix 21, promoted aperture opening ratio, but if make the contraposition deviation appears, to the storage capacitors value of each exposure region be changed, and this kind design makes storage capacitors to be connected with common electrode, when driving this membrane transistor, be easy to generate the phenomenon of electric leakage or collapse, Fig. 3 (b) is its vertical view.

Fig. 4 (a) is depicted as the storage capacitors of the third known membrane transistor LCD, it forms identical with the storage capacitors of first kind of known way, for avoid influencing aperture opening ratio with storage capacitors 14 be arranged in pixel capacitors around, make the storage capacitors position in upper strata shading matrix 21 as far as possible, but this structure will make storage capacitors and sweep trace very approaching, easily cause the two short circuit, and near easily deriving the delay capacity effect, Fig. 4 (b) is its vertical view because of too for storage capacitors and sweep trace and signal wire.

The storage capacitors of membrane transistor LCD of the present utility model is shown in Fig. 5 (a), its storage capacitors 14 is for being formed at simultaneously on the substrate with gate 11 metals and as first electrode of storage capacitors, with the brake-pole dielectric layer 12 and the ITO electrode 13 of deposition are formed jointly subsequently, first electrode design of storage capacitors becomes palisade, its covering scope is the middle body of pixel capacitors, each 1/4 place of lower limb on the pixel capacitors, referring to Fig. 5 (b) and Fig. 5 (c), the longitudinal component of storage capacitors is positioned at upper strata shading matrix scope, this structure is compared with first kind of known structure, under same stored capacity area situation, can obtain bigger aperture opening ratio, its storage capacitors of comparing with second kind of known way can be joined with common electrode, needn't worry electric leakage or collapse can take place, compare with the third known way, storage capacitors has reduced the short circuit chance, reduces to postpone capacity effect; Have more novelty and progressive according to the prepared product of the utility model than known technology.

Fig. 1 is the actual waveform of display element;

Fig. 2 (a) is the storage capacitors sectional view of first kind of known membrane transistor LCD;

Fig. 2 (b) is the vertical view of Fig. 2 (a);

Fig. 3 (a) is the storage capacitors sectional view of second kind of known membrane transistor LCD, and it relates to a part of being used as storage capacitors first electrode with gate electrode;

Fig. 3 (b) is the vertical view of Fig. 3 (a);

Fig. 4 (a) is the storage capacitors sectional view of the third known membrane transistor LCD, and its storage capacitors is designed to ring-type, be positioned at pixel capacitors around;

Fig. 5 (a) is a storage capacitors sectional view of the present utility model;

Fig. 5 (b) is the vertical view of Fig. 5 (a);

Fig. 5 (c) is another example vertical view of the present utility model.

Below describe the structure and the manufacture craft thereof of the storage capacitors of membrane transistor LCD of the present utility model in detail, and do one relatively with known various known ways.

Sputter layer of metal layer on glass substrate at first, etch gate electrode 11 and storage capacitors first electrode 14, then, according to usual manner growth counter-rotating stack book film electric crystal, first electrode design of storage capacitors becomes palisade, its covering scope each 1/4 place of lower limb that is the pixel capacitors middle body on the pixel capacitors, the longitudinal component of storage capacitors is positioned at upper strata shading matrix scope; Figure five (b) is its vertical view.

The storage capacitors of first kind of known way of comparison diagram 2 (b), storage capacitors longitudinal part of the present utility model is positioned at the upper strata shading matrix respectively, so this a part of storage capacitors area occupied does not influence aperture opening ratio, with the wide 30 μ m of the storage capacitors electrode of first kind of known technology, the long 160 μ m of pixel capacitors deduction upper strata shading matrix lap, wide 120 μ m, the wide 5 μ m of storage capacitors longitudinal component of the present utility model, then the storage capacitors aperture opening ratio of first kind of known technology is about 45% and reach 48% according to the utility model is designed under same stored capacity area situation.

The storage capacitors of second kind of known technology of comparison diagram 3 (b), because of its storage capacitors is and the shared electrode of gate electrode, so can't join with common electrode, the possibility that electric leakage or collapse are arranged, on the other hand this kind design at light shield to punctual if deviation is arranged, then cause the storage capacitors value difference of each exposure region, make LCD image deviation occur; And designed storage capacitors and the gate electrode of the utility model do not connect together, so storage capacitors can link to each other with common electrode, avoid above-mentioned danger, even total in addition the storage capacitors of palisade design on light shield is aimed to some extent deviation also do not influence its storage capacitors value.

The storage capacitors of the third known technology of comparison diagram 4 (b), its storage capacitors is looped around around the pixel capacitors, and because of with horizontal sweep trace with signal wire is very approaching longitudinally, situation of short circuit takes place so easily have each other, in addition, also easily make the delay capacity effect more obvious; And according to the storage capacitors of utility model design only in that vertically a part is close with signal wire, significantly reduced the short circuit chance, it is also not obvious to postpone capacity effect equally.

Storage capacitors electrode grizzly bar number of the present utility model, when considering that gold-tinted technology live width resolution is 3 μ m, the palisade bar number of its storage capacitors is no more than ten; Fig. 5 (C) is another vertical view of the utility model.

In sum, the utility model discloses a kind of storage capacitor structure of membrane transistor LCD, because the storage capacitors of membrane transistor LCD is designed to palisade, can increase its aperture opening ratio on the one hand, on the other hand since the palisade storage capacitors of membrane transistor LCD partly reduce with scanning and signal wire adjacent portion, but significant effective reduces each other short circuit phenomenon and reduces to postpone capacity effect.

Claims (4)

1. the storage capacitor structure of a membrane transistor LCD, first electrode design that it is characterized in that this storage capacitors becomes palisade and is positioned at the middle body of pixel capacitors, apart from pixel capacitors Ge Yue 1/4 place up and down, the longitudinal component of the palisade storage capacitors of membrane transistor LCD is positioned at the upper strata shading matrix, and palisade bar number is 2 to 10.

2. the storage capacitor structure of membrane transistor LCD according to claim 1 is characterized in that: the palisade storage capacitors by

(a) storage capacitors first electrode that forms with the gate deposition etch;

(b) brake-pole dielectric layer; And

(c) pixel capacitors ITO;

Three-decker constitutes.

3. the storage capacitor structure of membrane transistor LCD according to claim 2 is characterized in that the dielectric layer of first electrode for not depositing with gate.

4. the storage capacitor structure of membrane transistor LCD according to claim 2, the dielectric layer that it is characterized in that storage capacitors is the dielectric layer that does not deposit with brake-pole dielectric layer.

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