Patent EP0752611A2 successfully refreshed from Google Patents.
EP0752611A2
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EP
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LCD with bus lines overlapped by pixel electrodes and photo-imageable insulating layer therebetween
Assignee: LG Display Co Ltd
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Filing: 1996-06-05
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Granted: —
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Expires: 2016-06-05
Abstract
Abstract This invention is related to an active matrix liquid crystal display (AMLCD) having a high pixel aperture ratio. The display has an increased pixel aperture ratio because the pixel electrodes are formed over the insulating layer so as to overlap portions of the array address lines. Both the manufacturability and capacitive cross-talk of the TFT-based device are improved due to the use of a photo-imageable insulating layer between the pixel electrodes and the address lines. According to certain other embodiments, the insulating layer may be BCB (either photo-imageable or not) and/or have a dielectric constant less than about 3.0.
Inventors
- 👤 Tieer Gu
- 👤 Willem Den Boer
- 👤 John Z.Z. Zhong
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 17:52
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/80; H10F39/802; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/136; G02F1/1362; G02F1/136213; G02F1/136227; G02F1/136286; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/031; H10D30/0312; H10D30/0316; H10D30/0321; H10D30/60; H10D30/67; H10D30/6704; H10D30/6725; H10D86/00; H10D86/40; H10D86/441; H10D86/451; H10D86/60; H10F39/10; H10F39/12; H10F39/191; H10F39/195; G02F1/1333; G02F1/133357; G02F1/13606; G02F1/1368; G02F2202/00; G02F2202/42
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
163 words
A high aperture liquid crystal display comprising: first and second substrates; a liquid crystal layer sandwiched between said first and second substrates; an array of thin film transistors (TFTs) disposed on said first substrate, said array of TFTs including a plurality of address lines connected to said TFTs; an array of substantially transparent pixel electrodes disposed on said first substrate, a plurality of the pixel electrodes in said array of pixel electrodes overlapping at least one of said address lines thereby increasing the pixel aperture ratio of the LCD; a photo-imageable insulating layer disposed on said first substrate between said address lines and said pixel electrodes at least in the areas of overlap and areas adjacent source electrodes of the TFTs; and said photo-imageable insulating layer having a first group of contact vias defined therein by photo-imaging, wherein said pixel electrodes are in electrical communication with corresponding TFT source electrodes through said contact vias of said first group defined in said insulating layer.
Claim 2
Dependent Claim
60 words
The LCD of claim 1, further comprising an auxiliary storage capacitor electrode associated with each pixel electrode, and a second group of contact vias defined in said insulating layer by photo-imaging, and wherein each of said pixel electrodes is in electrical communication with a corresponding storage capacitor electrode through one of the vias in said second group of contact vias.
Claim 3
Dependent Claim
14 words
The LCD of claim 1, wherein said insulating layer is a negative resist layer.
Claim 4
Dependent Claim
17 words
The LCD of claim 1, wherein said insulating layer includes one of 2-Ethoxyethyl acetate and Benzocyclobutene (BCB).
Claim 5
Dependent Claim
19 words
The LCD of claim 1, wherein the dielectric constant ε of said insulating layer is less than about 3.0.
Claim 6
Dependent Claim
22 words
The LCD of claim 1, wherein said insulating layer includes an organic mixture of 2-Ethoxyethyl acetate, methacrylate derivative copolymer, and polyfunctional acrylate.
Claim 7
Dependent Claim
15 words
The LCD of claim 1, wherein said insulating layer is from about 2-3 µm thick.
Claim 8
Dependent Claim
24 words
The LCD of claim 1, wherein said insulating layer covers substantially the entire viewing area of the display except for contact vias formed therein.
Claim 9
Dependent Claim
18 words
The LCD of claim 1, wherein the pixel aperture ratio of the LCD is at least about 68%.
Claim 10
Dependent Claim
42 words
The LCD of claim 1, wherein the overlap distance or width is from about 0-2 µm in the overlap areas and the address line-pixel capacitance is less than about 12.0 fF when the length of the overlap area is about 100 µm.
Claim 11
Dependent Claim
14 words
The LCD of claim 10, wherein the capacitance is less than about 8.0 fF.
Claim 12
Dependent Claim
62 words
A TFT array structure comprising: an array of TFTs on a substrate, said TFTs being connected to a corresponding array of pixel electrodes; row and column address lines on said substrate for addressing said TFTs; and photo-imageable insulating means disposed between (i) said pixel electrodes; and (ii) said address lines so as to reduce crosstalk and permit said means to be photo-imaged.
Claim 13
Dependent Claim
149 words
A liquid crystal display with a large pixel aperture ratio comprising: a liquid crystal layer sandwiched between first and second substrates; an array of thin film transistors and corresponding pixel electrodes mounted on said first substrate, each of said thin film transistors including a semiconductor layer, a gate electrode connected to a gate address line, a drain electrode connected to a drain address line, and a source electrode connected to one of said corresponding pixel electrodes, and wherein said pixel electrode connected to said source electrode overlaps said gate and drain address lines along longitudinal edges thereof; and a substantially continuous insulating layer having a dielectric constant ε no greater than about 3.0 disposed between said pixel electrode and said address lines in sufficient thickness so as to reduce capacitive cross-talk in the display by reducing the pixel electrode-address line parasitic capacitance C PL in the areas of overlap.
Claim 14
Dependent Claim
97 words
The liquid crystal display of claim 13, wherein C PL is defined by the equation: C PL = ε · ε 0 · A d where ε 0 is 8.85 x 10 -14 F/cm, "d" is the insulating layer thickness in the overlap areas, and "A" is the area of the capacitor formed between said pixel electrode and said address lines in the overlap area; and wherein C PL is less than or equal to about 0.01 pF when the pixel pitch of the display is about 150 µm so as to reduce cross-talk in the display.
Claim 15
Dependent Claim
23 words
The liquid crystal display of claim 13, wherein the insulating layer thickness "d" is at least about 1.5 µm in the overlap areas.
Claim 16
Dependent Claim
34 words
The liquid crystal display of claim 15, wherein "d" is from about 2 to 3 µm in the overlap areas and said insulating layer has a degree of planarization of at least about 90%.
Claim 17
Dependent Claim
31 words
The liquid crystal display of claim 15, wherein the display has a pixel aperture ratio of at least about 65%, and a pixel pitch of from about 40 to 500 µm.
Claim 18
Dependent Claim
25 words
The liquid crystal display of claim 13, wherein said insulating layer includes Benzocyclobutene (BCB) and has a dielectric constant ε of about 2.7 or less.
Claim 19
Dependent Claim
90 words
A liquid crystal display comprising: a liquid crystal layer; a substantially transparent substrate adjacent said liquid crystal layer; an array of thin film transistors disposed on said substrate, said thin film transistors connected to address lines and acting as switching elements for energizing corresponding pixel electrodes; a substantially transparent planarization layer disposed on said array of transistors, said planarization layer being located between (i) said pixel electrodes; and (ii) said address lines; and wherein said planarization layer includes Benzocyclobutene (BCB) and has a dielectric constant of less than about 3.0.
Claim 20
Independent Claim
110 words
A method of making an array of semiconductor based thin film transistors (TFTs), the method comprising the steps of: providing a first substantially transparent substrate; forming an array of TFTs and corresponding address lines on the first substrate; depositing an organic photo-imageable insulating layer over both the TFT array and corresponding address lines; photo-imaging the insulating layer in order to form a first array of vias or contact holes therein; and forming an array of electrode members on the first substrate over the photo-imaged insulating layer so that the electrode members in the array are in communication with the corresponding TFTs through the first array of vias or contact holes.
Claim 21
Dependent Claim
32 words
The method of claim 20, further comprising the step of overlapping the address lines with the electrode members so that the photo-imaged insulating layer is disposed therebetween so as to reduce cross-talk.
Claim 22
Dependent Claim
43 words
The method of claim 21, further comprising the steps of (i) using the TFT array in one of a liquid crystal display and an image sensor, and (ii) forming the insulating layer so as to include one of photo-imageable BCB and 2-Ethoxyethyl acetate.
Claim 23
Dependent Claim
11 words
The display of claim 19, wherein the BCB layer is non-photo-imageable.
References Cited (Backward Citations)
No citation records indexed.
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