CN100508009C - Driving circuit of liquid crystal display panel - Google Patents

Abstract

The driving circuit of the liquid crystal display panel according to the invention comprises a substrate, a plurality of driving integrated circuit chips (driver IC chips) arranged on the substrate, a current supply source and a first lead group. The first wire group is provided with a plurality of wire segments for electrically connecting each driving integrated circuit chip with the current supply source in a parallel mode. Further, each of the conductive line segments has a shape such that each of the conductive line paths from the current supply source to each of the driver IC chips has an equal resistance value, so that each of the driver IC chips obtains the same input voltage. Therefore, the problem of uneven block colors of the display picture can be avoided.

Description

LCD panel drive circuit

technical field

The present invention relates to a driving circuit of a liquid crystal display panel, in particular to a driving circuit that enables each driver IC chip (driver IC chip for short) to obtain a same input voltage.

Background technique

TFT-LCD panels mainly use matrix-arranged TFTs to drive liquid crystal pixels with appropriate capacitors, transfer pads and other electronic components to produce rich and bright graphics. Generally speaking, a thin film transistor liquid crystal display panel includes an upper substrate with a color filter, a lower substrate, and a liquid crystal material filled between the upper substrate and the lower substrate. There are a plurality of scan or gate lines and signal lines (data or signal lines) perpendicular to each other on the lower substrate, and at least one thin film transistor is arranged at the intersection of each scan line and each signal line, Used as a switch device for a pixel.

Please refer to FIG. 1 , which is a schematic structural diagram of a liquid crystal display panel. As shown in FIG. 1 , a liquid crystal display panel 10 includes a substrate 12 and an X-printing wiring board 14 . In addition, the liquid crystal display panel 10 also includes a plurality of flexible printed circuit boards (flexible printing circuit board, FPC) 16, which are used to electrically connect the X-axis printed circuit board 14 and the substrate 12, and the substrate 12 and the flexible printed circuit board On the side where the board 16 is connected, a source driver IC chip 18 is provided, which is electrically connected to the flexible printed circuit board 16 .

A plurality of scanning lines S ₁ -S _m and a plurality of signal lines D ₁ -D _n are provided on the substrate 12 , and each scanning line S ₁ -S _m and each signal line D ₁ -D _n are vertically intersected for use in A plurality of pixels (not shown) arranged in a matrix are defined in an active region 19 on the substrate 12 . In addition, the substrate 12 also includes an outer lead bonding region (OLB) 20 and a gate driving circuit 22 disposed in the terminal bonding region 20, and the gate driving circuit 22 includes a driving IC chip 22a and 22b, for outputting switching/addressing signals to each scanning line S ₁ -S _m . The aforementioned source driver IC chip 18 is used to output image data signals to the signal lines D ₁ -D _n . The driving IC chips 18 , 22 a and 22 b are directly disposed on the surface of the substrate 12 using chip-on-glass (COG) technology. The driving circuit 22 also includes a plurality of wires 24 to electrically connect the driving IC chips 22a and 22b in series, and each wire 24 is directly fabricated on the surface of the substrate 12. This design is called a WOA (wiring on array) design. .

When the liquid crystal display panel 10 performs a display operation, as shown in FIG. 1, the driving voltage of a control signal 28 is output from the X-axis printed circuit board 14, and after passing through a flexible printed circuit board 16 and the wire 24, it is input again. Each driving IC chip 22a and 22b, and finally each driving IC chip 22a and 22b output the switching/addressing signal to each scanning line S ₁ -S _m . In addition, as shown in FIG. 2, the driver IC chips 22a and 22b are electrically connected in series, because the wire 24 produces impedances _R1 and _R5 , the driver IC chip 22a has a resistance _R3 inside, and the contact points of each component generate impedance R ₂ , R ₄ , and R ₆ therefore have a relatively large total resistance value.

The traditional wiring method is to widen the wire width as much as possible to reduce the resistance value, and then electrically connect the first IC to the last IC in series. However, limited by the interface impedance between the metal wire and ITO as high as 200Ω, the trace resistance difference between the first IC and the last IC may still be as high as 500Ω or more. Therefore, when the driving voltage of the control signal 28 is input to each of the driving IC chips 22a and 22b, the input voltages received by the driving IC chips 22a and 22b are different, and thus the output voltages are inconsistent. The voltage received by the first grid IC and the last grid IC may differ by about 0.3V, so that the luminance of the display screen of the liquid crystal display panel 10 is not the same, resulting in a bad phenomenon of uneven color (band mura). , reducing the display quality of the liquid crystal display panel 10 . The display screen 30 shown in FIG. 3 is a schematic diagram of uneven color blocks.

Please refer to Fig. 4, the known method for suppressing the color unevenness of this kind of block is to add a resistor 31 to the signal input on the printed circuit board, so that the input signal first produces a certain degree of shock distortion, and its amplitude is greater than The voltage difference generated by the impedance of the metal wiring on the panel is used to blur the uneven color of the block in this way. However, this method will increase the power consumption of the entire driving circuit.

Therefore, there is still a need for a good driving circuit of the liquid crystal display panel, so that each driving IC chip can obtain a same input voltage and avoid color unevenness of the blocks.

Contents of the invention

The object of the present invention is to provide a driving circuit of a liquid crystal display panel to solve the problem of uneven color of blocks caused by different input voltages to various ICs.

Therefore, the driving circuit of the liquid crystal display surface according to the present invention includes a substrate, a plurality of driver IC chips (driver IC chips) disposed on the substrate, a current supply source, and a first wire group. The first wire group has a plurality of wire segments to electrically connect each driving IC chip with the current supply source in parallel. Each wire segment has a shape such that each wire path from the current supply source to each driver IC chip has an equal resistance value, so that each driver IC chip obtains a same input voltage.

According to another aspect of the present invention, the driving circuit of the liquid crystal display panel of the present invention includes a substrate, a plurality of driver IC chips (driver IC chips) arranged on the substrate, a current supply source, and a first wire group, the The first wire group includes a wire to electrically connect each driving integrated circuit chip with a current supply source in parallel.

In the driving circuit of the liquid crystal display panel of the present invention, the electrical connection of a plurality of driving integrated circuit chips and the current supply source is arranged in parallel, and the shape of each wire segment can be further set, so that each driving IC chip is connected to the current supply source. The resistance difference of the wire path is close to zero, so that each driver IC chip can obtain a same input voltage to solve the problem of uneven color in the display screen of the liquid crystal display panel, and the power consumption of the driver circuit is low. Therefore, the increase can improve the display quality of the liquid crystal display panel.

Description of drawings

FIG. 1 shows a schematic structural diagram of a known liquid crystal display panel.

FIG. 2 shows a schematic diagram of resistance generated in a known driving circuit of a liquid crystal display panel.

FIG. 3 shows a schematic diagram of the known uneven color of the liquid crystal display panel.

FIG. 4 is a schematic diagram of a known method for solving the uneven color of a liquid crystal display panel.

FIG. 5 shows a schematic diagram of a driving circuit of a liquid crystal display panel according to the present invention.

FIG. 6 shows a schematic diagram of an embodiment of a driving circuit according to the present invention.

FIG. 7 shows a schematic diagram of the wire group structure of the driving circuit according to the present invention.

FIG. 8 is a table showing an example of combinations of wire segments A, B, and C in the present invention.

FIG. 9 is a table showing another example of the combination of wire segments A, B, and C in the present invention.

Description of reference symbols

10: Liquid crystal display panel

12: Substrate

14: X-axis printed circuit board

16: Flexible printed circuit board

18: Source driver IC chip

19: Active area

20: Terminal crimping area

22: Gate drive circuit

22a, 22b: driver IC chip

24: wire

28: Control signal

30: display screen

31: Resistance

32: Drive circuit

33: Thin film transistor substrate

34, 36: gate drive IC chip

35: active area

37: Terminal crimping area

38, 39a, 39b: wire segments

40: wire set

42: Current supply source

43: Liquid crystal display panel

44: Printed circuit substrate

46: Flexible printed circuit board

48: Source driver IC chip

50: wire group

A, B, C: wire segments

D ₁ ~ D _n : signal line

A, B, C: wire segments

D ₁ ~ D _n : signal line

S ₁ ~S _m : Scanning line

Detailed ways

As shown in Figure 5, according to the driving circuit 32 of the liquid crystal display panel of the present invention, comprise a thin film transistor substrate 33, two driver IC chips 34 and 36 are arranged on the thin film transistor substrate 33, a current supply source 42, and wire group 40 for connecting the driving IC chips 34 and 36 to the current supply source 42 in parallel.

The wire group 40 is composed of a plurality of wire segments, and the shape of each wire segment is not particularly limited, as long as it can be arranged on the substrate and meets the required resistance value, so that each parallel driver IC chip can obtain approximately the same voltage input value. . As shown in FIG. 5, the wire set 40 is composed of a main wire 38 and two branch wires 39a and 39b. One end of the main line 38 is connected to the current supply source 42 , and the branch lines 39 a and 39 b respectively connect the other end of the main line 38 to the driving IC chips 34 and 36 . Although the wire segment is called the main line and the branch line, the shape or length, width, and thickness of each wire segment are not master-slave. Supply source 42 is connected. Therefore, the shape or length, width, and thickness of each wire segment can have many variations, but the result should make the wire path connecting the current supply source 42 and the driver IC chip 34 the same as the wire path connecting the current supply source 42 and the driver IC chip 36. The wire paths have approximately equal resistance values, ie, the voltage drop from the connection current supply source 42 to each driver IC chip 34 and 36 should be approximately the same, so that each driver IC chip can obtain a substantially identical input voltage.

The wire group is made of conductive material, such as metal, alloy, or indium tin oxide (ITO). In addition, the metal or alloy may be aluminum, chromium, molybdenum, or aluminum-neodymium (AlNd) and the like.

Please refer to FIG. 6 , which shows the application of the driving circuit of the liquid crystal display panel 43 according to the present invention to the liquid crystal display panel. The liquid crystal display panel 43 includes a substrate 33 and a printed circuit substrate 44 . A plurality of scanning lines S ₁ , S _{2 .} . . to S _m , and a plurality of signal lines D ₁ , _{D 2} . m and n are positive integers respectively. It is used to define a plurality of pixels (not shown) arranged in a matrix in an active area 35 on the substrate 33 . The substrate 33 also includes a terminal pressing area 37 , and a gate driver IC chip 34 and 36 and wire sets 40 and 50 are disposed in the terminal pressing area 37 . In addition, the liquid crystal display panel 43 also includes a plurality of flexible printed circuit boards 46, which are used to electrically connect the printed circuit substrate 44 and the substrate 33, and the side terminal crimping area where the substrate 33 is connected to the flexible printed circuit board 46 Above 37 , a source driver IC chip 48 is arranged, which is electrically connected to the flexible printed circuit board 46 . The current supply comes from the printed circuit board 44 to output current to the driver IC chip via a flexible printed circuit board 46 .

The wire group can be manufactured simultaneously with the scanning lines on the substrate, and has the same material as the scanning lines, or can be manufactured simultaneously with the signal lines on the thin film transistor substrate, and has the same material as the signal lines, or can be made with the same material as the signal lines on the thin film transistor substrate. The pixel electrodes are fabricated at the same time and have the same material as the pixel electrodes. Preferably, when it is used as the wire of the gate driver IC chip, it is manufactured simultaneously with the scanning line, and can be made of the same material as the scanning line, which is convenient to manufacture and can have a smaller resistance value.

Please refer to FIG. 6 again, in the driving circuit of the liquid crystal display panel according to the present invention, there may be multiple sets of wire groups, for example, two wire groups 40 and 50 are included. The wire set 40 has been described in detail above. The wire group 50 is set in the same way as the wire group 40, and is also composed of a plurality of wire segments. It is independent from the wire group 40 and can be the same or different. The main reason is that each driver IC chip 34 and 36 must be connected in parallel. The current supply source 42 is connected, and the voltage drop of the connection current supply source 42 to the driver IC chip 34 is approximately equal to the voltage drop of the connection current supply source 42 to the driver IC chip 36. Therefore, the shape, length, and There are also many variations in the size of width and thickness. In the specific embodiment shown in FIG. 6 , the wire set 40 can be configured to transmit the on current, and the wire set 50 can be configured to transmit the off current.

It is known that the resistance of the wire is directly proportional to the length of the wire itself, and inversely proportional to the cross-sectional area of the wire. Therefore, the resistance value of the wire can be obtained through simulation calculation. Therefore, in the present invention, for a predetermined resistance value, the shape of each wire segment in the wire group, such as: length, width, and thickness, can have many combinations to achieve the desired. Please refer to FIG. 7 , which shows an embodiment of the wire group in the driving circuit of the liquid crystal display panel according to the present invention. The wire group is composed of wire segments A, B, and C. One end of the wire segment B is connected to the wire segment A, and the other end is connected to the driver IC chip 34 . One end of the wire segment C is connected to the wire segment A, and the other end is connected to the driver IC chip 36 . The tables in FIG. 8 and FIG. 9 respectively show two examples of possible combinations of the length, width, thickness and material of the wire segments A, B, and C. The combination of the wire groups shown in the table can be suitable as wires for transmitting the turn-on voltage (V _gg ) and turn-off voltage (V _ee ) of the thin film transistor.

In addition, the driving circuit described above is used to output switching/addressing signals to each scanning line, however, the present invention is not limited thereto, and the present invention can also be applied to a driving circuit that outputs image data signals to each signal line, This should be well known to those skilled in the art.

Compared with the known method of adding a resistor to the signal input on the printed circuit board to make the input signal oscillate and distort to a certain extent to solve the uneven color of the block, in the present invention, no resistor is added, Therefore, power consumption is not increased. The present invention makes the resistances between each driver IC chip and the current supply source almost equal, therefore, the voltages received by each driver IC chip are almost indistinguishable, and each driver IC chip can obtain a same input voltage to avoid display screen The problem of uneven color of the block, thereby improving the display quality.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the present invention.

Claims (17)

1. A driving circuit for a liquid crystal display panel, comprising: a substrate; A plurality of driving integrated circuit chips are arranged on the substrate; a current supply source; and A first wire group, which has a plurality of wire segments to electrically connect each of the driving integrated circuit chips with the current supply source in parallel, wherein each of the wire segments has a shape, so that each of the wire segments is connected from the current supply source to each of the current supply sources. The wire paths of the driving IC chips have equal resistance values so that each of the driving IC chips can obtain a same input voltage. 2. The driving circuit according to claim 1, wherein the first wire group comprises one or more of a metal layer, an alloy layer and an indium tin oxide layer. 3. The drive circuit as claimed in claim 1, wherein the first wire group comprises a first main line and a plurality of first branch lines, wherein the first main line is connected to the current supply source, and each of the first branch lines respectively connects The first main line is connected to each of the driving integrated circuit chips. 4. The driving circuit as claimed in claim 1, wherein a plurality of scanning lines and a plurality of signal lines are further arranged on the substrate. 5. The driving circuit as claimed in claim 4, wherein the driving integrated circuit chip is used to output a switching or addressing signal to each of the scanning lines. 6. The driving circuit as claimed in claim 4, wherein the driving integrated circuit chip is used to output an image data signal to each of the signal lines. 7. The driving circuit as claimed in claim 4, wherein the first wire group has the same material as the scan line. 8. The driving circuit as claimed in claim 4, wherein the first wire group has the same material as the signal wire. 9. The driving circuit as claimed in claim 1, further comprising a second wire group, which has a plurality of wire segments to electrically connect each of the driver integrated circuit chips with the current supply source in parallel, wherein each of the wire segments It has a shape such that each wire path from the current supply source to each of the driving integrated circuit chips has an equal resistance value, so that each of the driving integrated circuit chips obtains a same input voltage. 10 . The driving circuit as claimed in claim 9 , wherein the first conducting wire group carries a thin film transistor to turn on current, and the second conductive group carries a thin film transistor to turn off current. 11 . 11. The driving circuit according to claim 9, wherein the second wire group comprises one or more of a metal layer, an alloy layer and an indium tin oxide layer. 12. The drive circuit as claimed in claim 9, wherein the second wire group comprises a second main line and a plurality of second branch lines, wherein the second main line is connected to the current supply source, and each of the second branch lines respectively connects The second main line is connected with each of the driving integrated circuit chips. 13. The driving circuit as claimed in claim 9, wherein a plurality of scanning lines and a plurality of signal lines are further arranged on the substrate. 14. The driving circuit as claimed in claim 13, wherein the driving integrated circuit chip is used to output a switching or addressing signal to each of the scanning lines. 15. The driving circuit as claimed in claim 13, wherein the driving integrated circuit chip is used to output an image data signal to each of the signal lines. 16. The driving circuit as claimed in claim 13, wherein the second wire group has the same material as the scan line. 17. The driving circuit as claimed in claim 13, wherein the second wire group has the same material as the signal wire.

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