Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/136—Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit
  • G02F1/1362—Active matrix addressed cells
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1345—Conductors connecting electrodes to cell terminals
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/136—Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit
  • G02F1/1362—Active matrix addressed cells
  • G02F1/136259—Repairing; Defects
  • G02F1/136272—Auxiliary lines

Definitions

• the present invention generally relates to display devices and in particular a structure for canceling data line faults in display devices, for example in liquid crystal displays.
• Liquid crystal displays for television and computers are known in the art.
• a simplified liquid crystal display according to a prior art is shown in Figure 1.
• the display includes a grouping of liquid crystal elements 11 arranged in rows and columns.
• Each liquid crystal element is associated with a switching device 12, such as a thin film transistor (TFT).
• TFT thin film transistor
• the gate of each TFT 12 is connected to a selection line 13 so that an entire row of TFT is polarized simultaneously by each selection line 13.
• the selection lines 13 are electrically connected to the output terminals 17 of a scanner 21 of selection lines, which supplies the bias voltages to the selection lines.
• the data lines 14-1 to 14-N are located between the columns of display elements 11.
• the display elements 11 are connected to the data lines 14 by the conductive links of the TFTs 12.
• the data lines 14 are connected separately to the output terminals 15 of a data line scanner 16.
• the data lines 14 separately apply brightness voltages to the respective columns of display elements.
• Liquid crystal displays for television and computer monitors have a large number of columns of display elements, for example 1.440.
• a data line 14 and a data line scanner stage are required for each column of display elements.
• 1,440 data lines and 1,440 data line scanner stages are required for display.
• Each line is only a few microns wide and each stage of the scanner includes several semiconductor devices. For these reasons, the probability that one or more scanner stages comprise a defective semiconductor device or that one or more data lines have a break is very high.
• a defective sweeper stage is a serious defect because the result is a permanently visible line over the entire length of the column.
• a break in a data line is also a serious fault.
• the display elements which are located on the side of the data line scanner 16 with respect to the cutoff receive correct brightness voltages and operate normally. However, the display elements which are located on the other side of a cut-off do not receive the brightness voltages, and therefore these display elements appear as a permanent visible line on the display. Such visible lines are unacceptable in uses for television and computer monitors.
• the problem of data line breaks has been dealt with in the prior art by providing a single repair line 19 located immediately outside the display area. The repair line 19 passes over the ends of the data lines 14-1 to 14-N, but is isolated therefrom.
• the permanent visible line resulting from a cut 18 is canceled by using the repair line 19 to connect the cut data line to an uncut and fully passing data line.
• the data line 14-3 which includes the cut 18, and the uncut data line 14-2 or 14-1 can be welded to repair the line 19, preferably by laser welding. Connecting non-adjacent data lines may be preferable because it prevents adjacent data lines from receiving the same brightness signal, thereby resulting in a less noticeable defect.
• the repair line 19 is cut on both sides of the two data lines which have been linked together. Cutting the repair line 19 is necessary to isolate the connected data lines from the rest of the repair line 19 in order to make the rest of the repair line available for use with other cut data lines.
• Cutting the repair line 19 also decreases the parasitic capacity of the repair line.
• the display elements situated on the side of the data line scanner with respect to fault 18 continue to receive correct brightness voltages.
• the display elements which are located on the other side of the fault 18 receive the same brightness voltages as the data line to which they have been connected, the data line 14-2 in the example given. These display elements are thus switched on and off at the same time as the other display elements in the selected row, although they receive the wrong brightness voltages.
• the incorrect brightness of a column portion is a much less noticeable defect than a permanently visible line.
• the prior art is disadvantageous because, to clear each defect 18 of a data line, two steps of welding and two steps of cutting are required, which is time consuming and expensive.
• a structure for clearing data line faults in a display device having an array of display elements arranged in rows and columns includes a plurality of repair lines separately connecting the ends of sets of consecutive rows of data. Repair lines are used to electrically connect two data lines in an assembly. The number of repair lines is sufficient to connect all the data lines.
• Figure 1 shows a structure of a prior art for clearing data line faults.
• Figure 2 is a preferred embodiment.
• the data lines 14 extend beyond the last selection line 13-M to enter a first repair area 22, which includes the means necessary to cancel the effects of data line breaks.
• Each data line 14 has integrated tabs 24 projecting from both sides of the line.
• the repair lines 23 are substantially U-shaped elements dimensioned so that the legs of the U overlap the legs
• Each repair line 23 thus connects three consecutive data lines, in the preferred embodiment shown. As indicated by the shaded area 25, one end of each repair line 23 is permanently connected to a tab 24 of a data line 14.
• the repair lines 23 are isolated from the other two data lines overall, as indicated in 26. The repair lines 23 therefore divide, in fact, the data lines into sets of three. A cut in one of the data lines can be canceled simply by laser welding of one of the repair lines 23 to the data line comprising the cut.
• a second plurality of repair lines 27 is of identical configuration to that of repair lines 23 and divides the data lines 14 into second sets of three.
• the first and second repair lines are offset, whereby each of the second sets includes two data lines from one of the first sets, and a data line from another of the first sets.
• Repair lines 23 and 27 each have one end connected to alternating data lines.
• the repair lines 23 each have one end permanently connected to an odd numbered data line
• the repair lines 27 have one end permanently connected to an even numbered data line.
• the use of the second set of repair lines 27 is particularly advantageous when several consecutive data lines have breaks. In such a case, the breaks in the adjacent data lines can be canceled by different data lines so that adjacent data lines do not receive the same brightness signal.
• data lines 14-1 and 14-2 both have a cut
• the cut in line 14-1 can be canceled by welding from repair line 23-1 to data line 14- 1.
• the break in data line 14-2 can be canceled by welding the data line to repair line 27-2.
• Data lines 14-1 and 14-2 will then receive the same brightness signals as the lines. 14-3 and 14-4 respectively.
• a second repair area 28 is disposed between the first selection line 13-1 and the data line scanner 16.
• the data lines 14-1 to 14-N pass through the repair area 28 and are connected to the output terminals 15 of the data line scanner 16.
• a third and a fourth plurality of repair lines 29 and 30 are respectively arranged in the repair area 28 and intersect the data lines 14.
• the repair lines 29 and 30 divide the data lines into sets in the same manner as the repair lines 26 and 27.
• the repair lines in repair areas 22 and 28 are symmetrical; this is not an important characteristic, the repair lines in the two zones can be offset.
• Each repair line is permanently connected to a data line whereby the repair lines 29 are connected to the data lines of even numbers and the repair lines 30 to the data lines of odd numbers.
• the third and fourth sets of repair lines eliminate visible line effects caused by faulty stages of the data line scanner.
• the data line of the defective stage is connected to a nearby data line by one of the repair lines 29 or 30. If necessary, the defective stage can be disconnected from the associated output terminal 15, or the terminal of output can be disconnected from its associated data line, these two operations are generally carried out by laser cutting.
• the invention has an advantage because it causes the brightness of the visible lines to change continuously resulting from defective stages of the data line scanner, hence the replacement of an unacceptable defect with a barely perceptible defect and an improvement important display.
• Another advantage of the invention resides in the fact that the lines permanently visible caused by breaks in data lines are canceled using a single welding operation, whereas in the structure of the prior techniques, two steps welding and two cutting steps are required.

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• Physics & Mathematics (AREA)
• Nonlinear Science (AREA)
• Mathematical Physics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Devices For Indicating Variable Information By Combining Individual Elements (AREA)
• Liquid Crystal Display Device Control (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 1991
  • 1991-04-18 US US07/687,134 patent/US5298891A/en not_active Expired - Fee Related
• 1992
  • 1992-02-28 KR KR1019920703153A patent/KR930700882A/ko not_active Application Discontinuation
  • 1992-02-28 EP EP92907648A patent/EP0535188A1/fr not_active Withdrawn
  • 1992-02-28 WO PCT/FR1992/000189 patent/WO1992018895A1/fr not_active Application Discontinuation
  • 1992-02-28 JP JP92506901A patent/JPH05508239A/ja active Pending

Non-Patent Citations (1)

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