Active matrix-type liquid crystal display device and dot structure thereof
Technical field
The present invention relates to active matrix-type liquid crystal display device and the dot structure thereof of a kind of tool high aperture (aperture ratio).
Background technology
Figure 1A is a floor map, shows a known active matrix-type liquid crystal display device (active matrixliquid crystal display; AM LCD) active element substrate (active element substrate) is gone up the different retes that constitute a dot structure 100, Figure 1B is the sectional view that the A-A line crosscut along Figure 1A gets, and shows a reservior capacitor (storage capacitor) the Cst design of this dot structure 100.
Shown in Figure 1A, thin film transistor (TFT) (thin film transistor; TFT) 102 be illustrated as a n type amorphous silicon film transistor (n-type a-Si TFT), its grid 102g connects sweep trace 104, and source electrode 102s is connected to data line 106, and drain electrode 102d connects pixel electrode 110 via contact hole 108.Please refer to Figure 1B, reservior capacitor Cst is that gate insulator (gateinsulator) 114, passivation layer (passivation insulator) 116 are constituted with pixel electrode 110 at interval by common distribution 112.As the common distribution 112 of reservior capacitor Cst bottom electrode is when carrying out known the first metal layer (metal 1) technology and the grid 102g of thin film transistor (TFT) 102 forms jointly.
Generally speaking, the capacitance of reservior capacitor Cst depends on that both superimposed areas of upper and lower capacitance electrode, folded medium thickness and the specific inductive capacity of dielectric layer decide.Yet, above-mentioned reservior capacitor Cst design, folded dielectric layer blocked up (comprising gate insulator 114 and passivation layer 116 simultaneously) between two electrodes (common distribution 112 and pixel electrode 110) of its formation reservior capacitor Cst, if desire obtains required storage capacitors value, need significantly increase area as the common distribution 112 of bottom electrode.Yet common distribution 112 is made of lighttight the first metal layer material, so promptly causes the aperture opening ratio (aperture ratio) of this dot structure 100 significantly to descend.
Fig. 2 A and Fig. 2 B are for showing the synoptic diagram of the known pixel structure 200 with another kind of reservior capacitor Cst design, the sectional view that Fig. 2 B gets for the B-B line crosscut along Fig. 2 A.
Shown in Fig. 2 A, thin film transistor (TFT) 202 is illustrated as a n type amorphous silicon film transistor (n-type a-SiTFT), and its grid 202g connects sweep trace 204, and source electrode 202s is connected to data line 206, and drain electrode 202d then connects pixel electrode 212 via contact hole 220.Reservior capacitor Cst is made of with top electrode 210 bottom electrode 208.Pixel electrode 212 is connected with top electrode 210 via a contact hole 214.The bottom electrode 208 of reservior capacitor is when carrying out known the first metal layer (metal 1) technology and the grid 202g of thin film transistor (TFT) 202 forms jointly.210 of the top electrodes of reservior capacitor when carrying out known second metal level (metal2) technology and the source electrode 202s of thin film transistor (TFT) 202 and drain electrode 202d form jointly.
Please refer to Fig. 2 B, according to this reservior capacitor Cst design, the bottom electrode 208 of reservior capacitor Cst (the first metal layer formations) and top electrode 210 (second metal level formations) be only interval gate insulator 216 and interval passivation layer 218 not between the two.Therefore, compare, because of the thin area that is reduced two capacitance electrodes of the folded dielectric layer of two capacitance electrodes with the reservior capacitor design shown in aforementioned Figure 1A, the 1B.Yet; can not remain in gate insulator 216 for guaranteeing to conduct electricity foreign matter along bottom electrode 208 edges; consider allowed manufacturing tolerance simultaneously; in utilizing the actual manufacture process of liquid crystal array substrate of this design; bottom electrode 208 can form an area bigger than required capacitance usually; to guarantee that top electrode 210 can place in 208 coverage area of bottom electrode, so not only cause waste of material and the aperture opening ratio of this dot structure 200 is descended.
Summary of the invention
The technical problem to be solved in the present invention is: a kind of liquid crystal indicator and dot structure thereof are provided, and it can obtain good aperture opening ratio by the improvement structure of reservior capacitor, effectively promotes the contrast expression of display.
Technical solution of the present invention is: a kind of dot structure of tool reservior capacitor, it comprises a first metal layer (metal 1 layer), a gate insulator, one second metal level (metal 2 layer), a passivation layer and a pixel electrode.The first metal layer defines the area of grid of a shared distribution, one scan line and an active component, and the gate insulator of covering the first metal layer has the shared distribution of at least one contact hole with the exposed portion the first metal layer.Second metal level is formed on the gate insulator and defines drain electrode and the source region and a storage capacitors electrode of a data line, active component, and the storage capacitors electrode is via the made shared distribution of contact hole electrical connection the first metal layer of gate insulator.One passivation layer covers this second metal level, and a pixel electrode is formed on the passivation layer and with this passivation layer of storage capacitors electrode gap and constitutes a reservior capacitor.The storage capacitors electrode that is made of second metal level also can be used as the shading line in the dot structure.
The present invention also proposes a kind of active matrix-type liquid crystal display device, and it comprises: a filter sheet base plate forms on it and uses electrode altogether; One active element substrate; One liquid crystal layer is located between this filter sheet base plate and this active element substrate; And orthogonal sweep trace and the data line of multiple tracks, be formed on this active element substrate, two adjacent sweep trace and two adjacent data lines define a pixel region, and this pixel region has: an active component is formed at this sweep trace and this data line point of crossing place; One shared distribution is formed between the two adjacent sweep traces and is electrically connected this common electrode; One first dielectric layer covers this shared distribution and has at least one contact hole to expose this shared distribution; One shading metal level is formed on this first dielectric layer and via this contact hole and is electrically connected this shared distribution; One second dielectric layer covers this shading metal level; And a pixel electrode, being formed on this second dielectric layer, this pixel electrode and this shading metal interlevel constitute a reservior capacitor of this active matrix-type liquid crystal display device every this second dielectric layer.
In addition, the present invention also proposes another kind of active matrix-type liquid crystal display device, and it comprises: a filter sheet base plate forms on it and uses electrode altogether; One active element substrate; One liquid crystal layer is located between this filter sheet base plate and this active element substrate; Sweep trace that multiple tracks is orthogonal and data line are formed on this active element substrate; A plurality of thin film transistor (TFT)s, each thin film transistor (TFT) are formed at the place, point of crossing of this sweep trace and this data line; The shared distribution that a plurality of the first metal layers constitute, each shared distribution is formed between two adjacent sweep traces and is electrically connected this common electrode; One first dielectric layer covers described shared distribution and has a plurality of contact holes to expose each shared distribution; The storage capacitors electrode that one second metal level constitutes is formed on this first dielectric layer and via those contact holes and is electrically connected described shared distribution; One second dielectric layer covers this storage capacitors electrode; And a pixel electrode, be formed on this second dielectric layer and this pixel electrode and this second dielectric layer of this storage capacitors electrode gap constitute a reservior capacitor of this active matrix-type liquid crystal display device.
By design of the present invention, because of two capacitance electrodes of the reservior capacitor of the present invention thin passivation layer of spacer thickness only, so only need less electrode area can keep identical capacitance, therefore can effectively reduce lighttight metal electrode area and improve the aperture opening ratio of dot structure.Moreover, storage capacitors electrode of the present invention not palpiform becomes an area bigger than required capacitance to guarantee two interelectrode accurate contrapositions, so can not only effectively reduce lighttight metal electrode area and improve aperture opening ratio, the while is also saved metal electrode material and reduces cost.
Description of drawings
Figure 1A is a floor map, shows the different retes that constitute a dot structure on the active element substrate of a known active matrix-type liquid crystal display device.
The sectional view that Figure 1B gets for the A-A line crosscut along Figure 1A.
Fig. 2 A is a floor map, shows the different retes that constitute another dot structure on the active element substrate of a known active matrix-type liquid crystal display device.
The sectional view that Fig. 2 B gets for the B-B line crosscut along Fig. 2 A.
Fig. 3 is according to one embodiment of the invention, shows the part section simplified schematic diagram of an active matrix-type liquid crystal display device.
Fig. 4 A is the floor map according to one embodiment of the invention, shows the different retes that constitute a dot structure on the active element substrate of an active matrix-type liquid crystal display device.
The sectional view that Fig. 4 B gets for the C-C line crosscut along Fig. 4 A.
Fig. 4 C shows the equivalent circuit diagram according to dot structure of the present invention.
Fig. 5 is a synoptic diagram, shows that the present invention utilizes the embodiment of the capacitance electrode of second metal level formation as the shading line.
Fig. 6 is a synoptic diagram, shows that the present invention utilizes the capacitance electrode of second metal level formation another embodiment as the shading line.
The main element symbol description:
10, LCD 12, filter sheet base plate
14, active element substrate 16, liquid crystal layer
18, active component 22, pixel electrode
24,34, both alignment layers 26, colored filter
28, black matrix layer 32, common electrode
40, dot structure 42, the first metal layer
44, second metal level 46, pixel electrode
48, sweep trace 52, thin film transistor (TFT)
52c, channel layer 52d, drain electrode
52e, n+ amorphous silicon layer 52g, grid
52s, source electrode 54, shared distribution
56, data line 58, capacitance electrode
62, gate insulator 64, passivation layer
66, contact hole 100, dot structure
102, thin film transistor (TFT) 102d, drain electrode
102g, grid 102s, source electrode
104, sweep trace 106, data line
108, contact hole 110, pixel electrode
112, shared distribution 114, gate insulator
116, passivation layer 200, dot structure
202, thin film transistor (TFT) 202d, drain electrode
202g, grid 202s, source electrode
204, sweep trace 206, data line
208, bottom electrode 210, top electrode
212, pixel electrode 214,220, contact hole
216, gate insulator 218, passivation layer
Embodiment
Fig. 3 is one embodiment of the invention, shows an active matrix-type liquid crystal display device (active matrixliquid crystal display; AM LCD) 10 part section simplified schematic diagram.
As shown in Figure 3, LCD 10 comprises a filter sheet base plate 12 and an active element substrate (active element substrate) 14, and folder is established a liquid crystal layer 16 between two substrates.Be formed with active component 18, pixel electrode 22 and both alignment layers 24 towards a side of liquid crystal layer 16 on the active element substrate 14 as thin film transistor (TFT) (TFT).Filter sheet base plate 12 is formed with colored filter 26, separates shading black matrix layer 28, common electrode 32 and the both alignment layers 34 of the optical filter of different color towards a side of liquid crystal layer 16.
Fig. 4 A is the floor map according to one embodiment of the invention, show the different retes that constitute a dot structure 40 on the active element substrate 14 of an active matrix-type liquid crystal display device (AMLCD), and the sectional view that Fig. 4 B gets for the C-C line crosscut along Fig. 4 A is to show the reservior capacitor Cst structure of the present invention in this dot structure 40.
Shown in Fig. 4 A, form sweep trace (scanline) 48 that multiple tracks is parallel to each other and the data line (data line) 56 that is parallel to each other on the active element substrate 14, and two adjacent sweep traces 48 are orthogonal to two adjacent data lines 56 and corral goes out a pixel region.As tin indium oxide (Indium Tin Oxide; ITO) or indium-zinc oxide (Indium Zinc Oxide; IZO) pixel electrode 46 of nesa coating formation is distributed on this pixel region, and is formed at sweep trace 48 and place, data line 56 point of crossing as an active component of thin film transistor (TFT) 52.
Please also refer to Fig. 4 A and Fig. 4 B, in this dot structure 40, one the first metal layer (metal 1layer) 42 is formed on the active element substrate 14, and this first metal layer 42 comprises the grid 52g and a shared distribution (common line) 54 of sweep trace 48, thin film transistor (TFT) 52.The first metal layer 42 can by deposition as the metal film of chromium (Cr), tantalum (Ta), aluminium/molybdenum (Al/Mo) on substrate 14, form through the photoengraving pattern metallization processes again.
One gate insulator (gate insulator) 62 with dielectric effect covers this first metal layer 42, and gate insulator 62 can the chemical vapor deposition mode be deposited on formation on the first metal layer 42 with silicon nitride (SiN) material.
Thin film transistor (TFT) channel layer 52c, the n+ amorphous silicon layer 52e and one second metal level (metal 2 layer) 44 that constitute just like amorphous silicon film are formed on the gate insulator 62.Second metal level 44 comprises source electrode 52s, drain electrode 52d, data line 56 and a storage capacitors electrode 58 of thin film transistor (TFT) 52, second metal level 44 can be by the metal film of sputter such as aluminium/chromium (Al/Cr), aluminium/titanium (Al/Ti), titanium (Ti), molybdenum/aluminium/molybdenum (Mo/Al/Mo) on gate insulator 62, and second metal level 44 forms the zone in thin film transistor (TFT) 52 and goes up covering channel layer 52c and n+ amorphous silicon layer 52e, forms with the photoengraving pattern metallization processes again.Source electrode 52s and drain electrode 52d are disposed at the channel layer 52c both sides of grid 52g top, and the grid 52g of thin film transistor (TFT) 52, source electrode 52s and drain electrode 52d electrically connect with sweep trace 48, data line 56 and pixel electrode 46 respectively.
One passivation layer (passivation insulator) with dielectric effect is arranged on the gate insulator 62 and second metal level 44, with source electrode 52s, drain electrode 52d, data line 56 and the storage capacitors electrode 58 of cover film transistor 52, this passivation layer for example can be made by silicon nitride (SiN) material.Transparent pixels electrode 46 as ITO or IZO nesa coating formation is arranged on this passivation layer 64.
Detailed shown in Fig. 4 B, according to design of the present invention, the reservior capacitor Cst of dot structure 40 is formed every passivation layer 64 with pixel electrode 46 between the two by the capacitance electrode 58 that second metal level 44 constitutes.Moreover gate insulator 62 has opening and runs through the contact hole 66 of gate insulating film with formation, and second metal level 44 capacitance electrode 58 that constitutes and the shared distribution 54 that the first metal layer 42 constitutes are electrically connected via contact hole 66.
Compare with the known configurations of Figure 1B, because of two capacitance electrodes 58,46 of reservior capacitor Cst of the present invention passivation layer 64 at interval only, so only need less electrode area can keep identical capacitance, therefore can effectively reduce lighttight metal electrode area and improve the aperture opening ratio of this dot structure 40.On the other hand, compare with the known configurations of Fig. 2 B, being the capacitance electrode 58 that is made of second metal level 44 because of reservior capacitor Cst of the present invention, both are constituted with pixel electrode 46, so capacitance electrode 58 not palpiform becomes an area bigger than required capacitance to guarantee two interelectrode accurate contrapositions, so can not only effectively reduce lighttight metal electrode area and improve aperture opening ratio, the while is also saved metal electrode material and reduces cost.Moreover in present liquid crystal array substrate manufacture process, the design thickness of passivation layer 64 is thinner than gate insulator 62 usually.Therefore, two capacitance electrodes 58,46 of the present invention are the thin passivation layer 64 of spacer thickness only, so can further reduce required electrode area aperture opening ratio is improved more.
Fig. 4 C shows according to the equivalent circuit diagram of the dot structure of the present invention's design, can know the electric connection mode of finding out reservior capacitor of the present invention and other elements by Fig. 4 C.The grid 52g of thin film transistor (TFT) 52 is electrically connected sweep trace 48, source electrode 52s is electrically connected data line 56 and drain electrode 52d is electrically connected pixel electrode 46.Shared distribution 54 is formed at two 48 of adjacent sweep traces and is electrically connected the common electrode 32 that is formed on the filter sheet base plate 12.Common electrode 32 and shared distribution 54 can apply a reference voltage by the outside, and a data drive circuit (not shown) data signal is given data line 56, and a gate driver circuit (not shown) transmits scanning-line signal to sweep trace 48.Pixel electrode 46 and the common electrode on the filter sheet base plate 12 32 on the active element substrate 14 constitute a liquid crystal capacitance Clc, its capacitance electrode 58 that is made of second metal level 44 of reservior capacitor Cst, the shared distribution 54 that constitutes via contact hole 66 and the first metal layer 42 electrically connects.Two capacitance electrodes of reservior capacitor Cst are the thin passivation layer 64 of spacer thickness only, thus only need the smaller electrode area can obtain required capacitance, and can effectively improve aperture opening ratio.
Moreover according to design of the present invention, the distributing position of the capacitance electrode 58 that is made of second metal level 44 be not limited to be positioned at the cross direction profiles in the middle of the pixel region as illustrated in Fig. 4 A, and visual actual needs is changed.For example, the pixel electrode 46 of low substrate of LCD device is that the common electrode (not shown) of corresponding upper substrate is with common generation vertical electric field, but pixel electrode 46 distributed areas are usually less than the distributed areas of common electrode, so at pixel electrode 46 peripheries also to should common electrode but do not have the part infrabasal plate location that pixel electrode 46 distributes, be easy to generate the distortion electric field and influence the sensing control of liquid crystal molecule under conducting state (Von), cause light leakage phenomena.Therefore, as shown in Figure 5, also the capacitance electrode 58 that second metal level 44 constitutes can be extended to form in the pixel edges of proximity data line 56, constitute left and right sides twice shading line and the effect that obtains to cover the unusual light of leakage.Certainly, formation position, area and the thickness of the shading line that this capacitance electrode 58 constitutes do not limit, and only need obtain good shaded effect and get final product.For example, also can be as shown in Figure 6, be formed in four rims of pixel region and frame encloses whole pixel region with shading is linear, with the pixel edge exposure problem of avoiding fully causing because of various factors.
Though the present invention discloses with specific embodiment; but it is not in order to limit the present invention; any those skilled in the art; the displacement of the equivalent assemblies of under the prerequisite that does not break away from design of the present invention and scope, having done; or, all should still belong to the category that this patent is contained according to equivalent variations and modification that scope of patent protection of the present invention is done.