KR20050007115A - Tft display device - Google Patents

Abstract

PURPOSE: A TFT display device is provided to improve display quality without any visible luminance difference, by restraining line resistances from gate power circuits to gate driving modules and the change of time constants of gate lines per the gate driving module. CONSTITUTION: A TFT display device includes a TFT substrate(10) having a plurality of gate lines(11) formed on an insulating substrate and a plurality of gate line input terminals(11i) formed by drawing each gate line to its peripheral portion. Two or more gate driving modules(22) are connected with the gate line input terminals for controlling voltage supply timing per gate line. A display control substrate(40) supplies gate driving voltages to the gate driving modules. Gate power supply lines(41) are provided in the peripheral parts of the TFT substrate, for supplying the gate driving voltages from the display control substrate to the gate driving modules. The display control substrate includes gate power circuits(212,213) for generating the gate driving voltages and a resistor(70) having a resistance value higher than a line resistance from the gate power supply line to the gate driving module nearest to the display control substrate. The gate driving voltages are supplied to the gate power supply line through the resistor.

Description

T.F.T. Display device {TFT DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TFT (Thin Film Transistor) display device, and more particularly, to driving control of a gate line in a TFT display device using a TFT substrate.

The liquid crystal display device is constructed by enclosing a liquid crystal between a TFT substrate and a color filter substrate. In the TFT substrate, a plurality of pixel electrodes are formed on an insulating transparent substrate made of glass or the like, and a thin film transistor TFT is formed for each pixel electrode. On the other hand, in the color filter substrate, a common electrode is formed on an insulating transparent substrate made of glass or the like, and image display is performed by controlling the orientation direction of liquid crystal molecules by an electric field between the pixel electrode and the common electrode.

11 is an explanatory diagram showing a schematic configuration of a TFT substrate and its control circuit. In Fig. 1, reference numeral 10 denotes a TFT substrate, 20 denotes a gate control circuit, and 30 denotes a source control circuit. In the TFT substrate 10, a plurality of gate lines 11 are formed in parallel, and a plurality of source lines 12 are formed in parallel to the gate lines 11, and the gate lines 11 and TFT 13 is formed at each intersection of the source line 12. In these TFTs 13, the gate electrode G and the source electrode S are connected to the gate line 11 and the source line 12, respectively, and the drain electrode is connected to the corresponding pixel capacitor 14.

The voltage of the gate line 11 is controlled by the gate control circuit 20, and the TFT 13 is sequentially turned on for each gate line 11. The voltage of the source line 12 is controlled by the source control circuit 30, and supplies the write data corresponding to the luminance to the TFT 13 in the on state. That is, in the TFT 13, the gate-on voltage Vgh is applied to the gate electrode G only in a very short period during which data writing is performed, and the transistor 13 is turned on. In other periods, the gate-off voltage Vgl is applied and turned off. . In this on-state period, the pixel capacitor 14 is charged and discharged through the TFT 13, and the voltage (recording data) of the source line 12 is recorded.

12 is a diagram showing an example of the configuration of a conventional TFT substrate and its control circuit. In the drawing, reference numeral 21 denotes a gate controller board, 22 a gate driving module, 31 a source control board, and 32 a source driving module.

The gate control board 21 and the gate drive module 22 correspond to the gate control circuit 20 of FIG. 11. In the gate controller board 21, a timing signal generator 211, a gate-on power supply circuit 212, and a gate-off power supply circuit 213 are formed on the printed circuit board 210, and a timing signal necessary for applying a gate driving voltage. The gate on voltage Vgh and the gate off voltage Vgl are generated.

The gate driving module 22 is a flexible thin circuit called TCP (Tape Carrier Package) or COF (Chip On Film) formed on the insulating film 23 by the gate driving circuit 24 formed of the gate driver IC, and the gate The gate driving voltage is applied to each gate line 11 based on the timing signal from the control board 21, the gate on voltage Vgh, and the gate off voltage Vgl. That is, based on the timing signal, the gate on voltage Vgh is applied to the gate line 11 to be recorded, and the gate off voltage Vgl is applied to the other gate lines 11.

Similarly, the source control board 31 and the source drive module 32 in the figure correspond to the source control circuit 30 in FIG. The source control board 31 is composed of a printed board 310 having a circuit (not shown) for generating a timing signal or recording data. The source drive module 32 is a flexible thin circuit in which a source drive circuit 34 made of a source driver IC is formed on the insulating film 33 and is based on timing signals and recording data from the source control board 31. Thus, a write voltage is applied to each source line 12.

In this TFT substrate, part of the gate control circuit 20 is configured as the gate drive module 22 made of some flexible thin film. Similarly, part of the source control circuit 30 is configured as a source drive module 32 made of any flexible thin film. For this reason, there is an advantage that the liquid crystal display device can be miniaturized by using the TFT substrate.

13 is a view showing another example of a conventional TFT substrate and its control circuit. Reference numeral 40 in the figure denotes a display control substrate, and 41 and 42 denote wirings on a TFT substrate.

The display control board 40 corresponds to the gate control board 21 and the source control board 31 in FIG. 12, and includes a printed board 400 disposed in the vicinity of the source driving module 32. That is, the display control board 40 is a source control board 31 having the circuits 211 to 213 formed on the gate control board 21 in FIG. 12.

The timing signal, the gate on voltage Vgh, and the gate off voltage Vgl are transmitted to one gate driving module 22 closest to the display control substrate 40 through the wiring 41 on the TFT substrate 10, and also to the TFT substrate ( 10 is transferred in order between the gate driving modules 22 through the wiring 42 on the wiring 42. In other words, the wirings 41 and 42 include a gate voltage supply line for supplying a gate driving voltage to each gate driving module 22 on the TFT substrate 10.

In this TFT substrate, since the gate control board 21 and the source control substrate 31 are concentrated on one substrate (the display control substrate 40), the liquid crystal display device can be made smaller and lighter by using the TFT substrate. can do.

In the wirings 41 and 42 of FIG. 13, a conductive thin film formed on the TFT substrate 10 by photolithography technique is used. In addition, in consideration of the manufacturing cost, a conductive layer used in the image display area of the TFT substrate 10, for example, a layer made of the same material and film thickness as the gate line 11 is used. For this reason, compared with the case of FIG. 12, the wiring resistance in a gate voltage supply line becomes large, and the voltage applied to the gate line 11 for every gate drive module 22 arises.

When the gate-off voltage Vgl fluctuates, even if there is no fluctuation in the amount of charge stored in the pixel capacitor 14, the potential of the pixel electrode relative to the common electrode fluctuates and the luminance changes. For this reason, when the gate-off voltage Vgl differs for each gate driving module 22, a phenomenon called block spots occurs in which the luminance in the screen varies for each region corresponding to the gate driving module 22, and the screen appears to be divided. .

The proposal for solving such a problem is disclosed by patent document 1, for example. The proposal disclosed in Patent Document 1 provides a resistance element in the gate driving circuit 24 and adjusts the resistance value so as to linearly change the gate driving voltage for each gate driving circuit 24.

[Patent Document 1]

Japanese Patent Laid-Open No. 2001-228834

In Patent Literature 1, by adjusting the resistance value in the gate driving circuit 24, the gate driving voltage is changed linearly to solve the problem that the screen appears to be divided. For this reason, it is necessary for each gate drive module 22 to have a different resistance element built therein, and components cannot be shared, resulting in an increase in manufacturing cost.

In addition to the static fluctuations of the gate drive voltage pointed out in Patent Document 1, the reason why the screen is divided may include dynamic fluctuations in the gate drive voltage, that is, transient voltage level fluctuations during voltage fluctuations. .

In general, the TFT 13 has a coupling capacitance between the source electrode S and the gate electrode G. For this reason, when the voltage of the source line 12 fluctuates, the voltage of the gate line 11 also changes temporarily under the influence. In short, every time the source driving voltage is changed, the operation of changing the voltages of all the gate lines 11 to which the gate off voltage Vgl is applied at all is repeated every recording period.

Such a temporary voltage fluctuation of the gate line is then attenuated in accordance with a predetermined time constant and closer to the original gate off voltage Vgl. By the way, when the time constant differs for each gate drive module 22, the voltage value in attenuation differs between the gate drive modules 22, and block spots will arise.

This invention is made | formed in view of the said situation, and an object of this invention is to provide the TFT display apparatus which can perform uniform screen display at low cost. It is also an object of the present invention to provide a TFT display device which can suppress dynamic fluctuations in the gate driving voltage and can suppress or prevent block irregularities. In addition, an object of the present invention is to provide a TFT display device having a high display quality, which can be miniaturized and reduced in weight.

Fig. 1 is a perspective view showing an example of a TFT display device according to the present invention, in which a state upon assembly of a liquid crystal display device is shown.

2 is a cross-sectional view of the TFT display.

Fig. 3 is a diagram showing an example of the configuration of main parts of the TFT display device according to the first embodiment, and the TFT substrate is shown simultaneously with the control circuit.

4 is a block diagram showing an example of a circuit configuration of the gate driving circuit 24 of FIG.

5 is a view showing a display state of a liquid crystal display device used in an experiment for confirming the effect of the present invention.

Fig. 6 is a diagram showing an example of the variation of the gate-off voltage due to the difference in time constant.

Fig. 7 is a diagram showing an example of the configuration of main parts of the TFT display device according to the second embodiment of the present invention.

Fig. 8 is a diagram showing an example of the configuration of main parts of the TFT display device according to the third embodiment of the present invention.

Fig. 9 is a diagram showing an example of the configuration of main parts of the TFT display device according to the fourth embodiment of the present invention.

Fig. 10 is a diagram showing an example of the configuration of main parts of the TFT display device according to the fifth embodiment of the present invention.

11 is an explanatory view showing a schematic configuration of a TFT substrate and its control circuit.

12 is a view showing an example of the configuration of a conventional TFT substrate and its control circuit.

13 is a view showing another example of a conventional TFT substrate and its control circuit.

* Description of the symbols for the main parts of the drawings *

10, 17, 18: TFT substrate 11: Gate line

11i: Gate line input terminal 12: Source line

12i: Source line input terminal 14: Pixel capacity

16: image display area 21: gate control panel

210: printed circuit board 211: timing signal generator

212: gate-on power supply circuit 213: gate-off power supply circuit

22: gate drive module 23: insulating film

24: gate driving circuit 240: timing control circuit

40: display control board 41-43: thin film wiring

50: front case 70: resistance element

71: Capacitive element Vgh: gate on voltage

Vgl: Gate Off Voltage

In the TFT display device according to the present invention, a plurality of gate lines are formed on an insulating substrate, and each TFT is connected to a plurality of gate line input terminals and a TFT substrate having a plurality of gate line input terminals formed by drawing each gate line to a periphery thereof. And at least two gate driving modules for controlling the voltage supply timing for each gate line, and a display control substrate for supplying gate driving voltages to the gate driving modules. In the peripheral portion of the TFT substrate, a gate power supply line for transmitting a gate driving voltage from the display control substrate to the gate driving module is provided. The display control board further includes a gate power supply circuit for generating a gate drive voltage and a resistance element having a resistance value higher than the wiring resistance of the gate power supply line to the gate drive module closest to the display control board. This resistance element is supplied to the gate power supply line.

By such a configuration, it is possible to suppress fluctuations in the wiring resistance from the gate power supply circuit to each gate drive module, and to suppress a large fluctuation in the time constant of the gate line for each gate drive module. Therefore, it is possible to suppress the occurrence of the visible luminance difference due to the dynamic fluctuation of the gate driving voltage with the gate driving module. For example, when the gate driving voltage is temporarily varied in accordance with the image pattern and the AC driving method due to the coupling capacitance between the source electrode and the gate electrode of the TFT, the gate driving is performed for each gate driving module when the variation is attenuated. Voltage fluctuations can prevent block irregularities from occurring.

In the TFT display device according to the present invention, the display control substrate has a capacity larger than the sum of the input capacitance of the gate driving module closest to the display control substrate and the wiring capacitance of the gate power supply line to the gate driving module. And a capacitor, which is connected in parallel to the gate power supply line on the gate power supply line side rather than the resistance element.

By such a configuration, it is possible to suppress fluctuations in the wiring capacitance from the gate power supply circuit to each gate driving module and fluctuations in the input capacitance of each gate driving module, and to suppress a large fluctuation in the time constant of the gate line for each gate driving module. . Therefore, it is possible to suppress the occurrence of the visible luminance difference due to the dynamic change in the gate driving voltage for each gate driving module.

In the TFT display device according to the present invention, the gate power supply line is made of a conductive thin film formed on a TFT substrate. By such a configuration, while the TFT display device is made smaller or lighter, a large difference occurs in the time constant of the gate line for each gate driving module, and it can be suppressed or prevented from being recognized as block spots. In other words, the display quality can be made both compact and lightweight.

In the TFT display device according to the present invention, the gate drive module is connected in series via a gate power supply line. By connecting the gate drive modules in series, the TFT display device can be reduced in size and weight, and a large difference in the time constant of the gate lines can be generated for each gate drive module, thereby preventing or preventing the display from being viewed as block spots. That is, it is possible to achieve both small size and light weight and display quality.

In the TFT display device according to the present invention, the gate power supply line is branched on the gate drive module side rather than the resistor element, and each of the above gate drive modules is connected to the gate power supply line after the branch, respectively, and is parallel to each other. Connected. By such a configuration, even when the gate drive modules are connected in parallel, the time constant of the gate line can be suppressed from fluctuating greatly for each gate drive module.

Further, the TFT display device according to the present invention is provided at the output terminal of the gate-off power supply circuit, in which the resistance element supplies a gate-off voltage for controlling the TFT in the off state. By such a configuration, it is possible to suppress or prevent the occurrence of block spots due to temporary variation in the gate off voltage.

Further, in the TFT display device according to the present invention, the gate driving module is made of an insulating film formed of a gate driving circuit, and a gate driving voltage is supplied to the gate driving circuit on the insulating film through a gate power supply line. By such a configuration, it is possible to attain both compact size and light weight of the TFT display and display quality.

In the TFT display device according to the present invention, the insulating film is connected in series to the display control substrate through a gate power supply line. By such a configuration, it is possible to suppress or prevent the TFT display device from being small and lightweight, and having a large difference in the time constant of the gate line for each gate driving module, and being perceived as block spots.

In the TFT display device according to the present invention, the gate drive module is formed of a semiconductor chip provided on a TFT substrate. This configuration can further reduce the size and weight of the TFT display without degrading the display quality.

[Examples of the Invention]

(Example 1)

Fig. 1 is a perspective view showing an example of a TFT display device according to the present invention, in which a state of assembly of a liquid crystal display device is shown. In the drawings, reference numeral 50 denotes a front case, 51 a liquid crystal panel, 52 a backlight, 53 a rear case, and 54 a color filter substrate.

The liquid crystal panel 51 includes two or more gate drive modules 22 formed of the same circuit configuration on one side of the TFT substrate 10 by enclosing liquid crystal to attach the color filter substrate 54 to the TFT substrate 10. ), Two or more source drive modules 32 are arranged on one adjacent side of the other, and the display control board 40 is connected to the source drive module 32.

The liquid crystal display device can be obtained by superimposing a backlight on the rear surface of the liquid crystal panel and storing it in a case made of the front case 50 and the back case 53. This liquid crystal display device is generally called a liquid crystal module and is used by attaching various peripheral circuits or the like.

FIG. 2 is a cross-sectional view of the TFT display, and a cross section parallel to the source line in the assembled state of the liquid crystal display of FIG. 1 is shown. The source drive module 32 made of an insulating film having flexibility is bent in the case, and the display control substrate 40 is disposed on the back side of the backlight 52. In addition, the gate drive module 22 (not shown) is also bent in the case. For this reason, compared with the area of a display screen, the whole liquid crystal display device can be made small. Further, by using the display control board 40 integrating the gate control board and the source control board, it is further downsized and reduced in weight.

3 is a diagram showing an example of the configuration of main parts of the TFT display device according to the first embodiment, and the TFT substrate is shown simultaneously with the control circuit. In the figure, reference numeral 16 denotes a display area of the TFT substrate, and 70 denotes a resistor. Compared with FIG. 13 (prior art), the resistor 70 is provided at the output terminal of the gate-off power supply circuit 213 on the display control substrate 40.

At the same time as the source control circuit, the display control substrate 40 is provided with a timing signal generator 211 as a gate control circuit, a gate-on power supply circuit 212 and a gate-off power supply circuit 213. The timing signal and the gate on voltage Vgh are the source. It is supplied to the TFT substrate 10 through the wiring on the insulating film 33 constituting the drive module 32. Meanwhile, the gate off voltage Vgl is output through the resistance element 70 on the display control substrate 40 and supplied to the TFT substrate 10 through the wiring on the insulating film 33 constituting the source driving module 32. do.

These signals are input to the gate driving module 22 through the thin film wirings 41 and 42 formed on the TFT substrate 10 and supplied to the gate driving circuit 24 on the gate driving module 22. That is, the gate drive module 22 is connected in series to the display control substrate 40 through the thin film wirings 41 and 42 on the TFT substrate 10, and the output signal from the display control substrate 40 is thin film wiring 41. It is transmitted to the closest gate driving module 22 through, and also in order between the adjacent gate driving module 22 through the thin film wiring 42.

The resistance value of the resistance element 70 is previously determined to be higher than at least the wiring resistance of the gate power supply line (thin film wiring 41) to the gate drive module 22 closest to the display control substrate 40. At this time, it is more preferable that the predetermined value is sufficiently higher than the wiring resistance.

Among the conductive layers used to form the display area 16, the gate line 11 usually has the highest electrical conductivity and is suitable for the thin film wirings 41 and 42. In the case of using the same layer as the gate line as the thin film wirings 41 and 42, by connecting the gate driving modules 22 in series, a large area is required at the periphery of the TFT substrate 10 without intersecting with the gate line. The wirings 41 and 42 can be formed without doing this.

Each gate driving module 22 is assigned with a plurality of gate lines 11, and performs voltage control of the assigned gate lines 11. Each gate line 11 is led to a peripheral portion (outside of the display region 16) on the side of the gate drive module 22 on the TFT substrate 10, and a gate line input terminal 11i is formed. The output line of the corresponding gate drive module 22 is connected to this gate line input terminal 11i. At this time, similarly, the output terminal of the source driving module 32 is connected to the source line input terminal 12i which led the source line 12 to the periphery of the source driving module 32 side on the TFT substrate 10.

4 is a block diagram showing an example of a circuit configuration of the gate driving circuit 24 of FIG. The gate driving circuit 24 is composed of a timing control circuit 240 corresponding to each gate line 11 to be controlled, and the timing signal, the gate on voltage Vgh, and the gate off voltage Vgl are each timing control circuit. It is input at 240. The timing control circuit 240 selectively outputs either the gate on voltage Vgh or the gate off voltage Vgl to the gate line input terminal 11i based on the timing signal.

5 and 6 are diagrams illustrating experiments performed to confirm the effects of the present invention. 5 shows a display state of the liquid crystal display device used for the experiment, and FIG. 6 shows an example of the variation of the gate-off voltage due to the time constant difference.

In the liquid crystal display device used in this experiment, a plurality of pixels of the same color are arranged in the longitudinal direction, and a plurality of pixels of different colors are arranged in the order of RGB in the horizontal direction, and an RGB longitudinal stripe is formed. have.

In addition, AC driving is performed on a pixel basis. That is, with respect to the write voltage (source driving voltage) to any pixel, the polarity of the write voltage to each pixel adjacent to the top, bottom, left, and right of the pixel is inverted and driven, and the polarity of the write voltage to each pixel is framed. I reverse it every time. Each longitudinal stripe of such a liquid crystal display device is displayed in black, and the remaining longitudinal stripes are turned on to have a predetermined halftone, and the input voltage value of the gate-off voltage Vgl in each gate driving module 22 is measured. It was.

FIG. 6 is a diagram showing measured values of the gate-off voltage Vgl when no resistance element 70 is provided. In the drawing, reference numeral 60 denotes an input voltage value to the gate driving module 22 closest to the gate-off power supply circuit 213 after passing through the thin film wiring 41, and 61 denotes a next gate driving module 22 after passing through the thin film wiring 42. The input voltage value 62) is the output voltage value from the gate drive module 22 immediately before one, and the input voltage value to the farthest gate drive module 22 after passing through the thin film wiring 42.

In this figure, the gate-off voltage Vgl, which should be constant, changes temporarily every recording period, after which the variation is attenuated according to the time constant. At this time, the closer the gate-off power supply circuit 213 is, the shorter the time constant is. Therefore, the attenuation is rapidly attenuated. A variation in each gate driving module 22 is output to the gate-off voltage value Vgl during attenuation, resulting in block spots. In particular, the difference between the closest gate drive module 22 and the other gate drive module 22 is remarkable.

The variation in these measured values is remarkably improved when the resistance element 70 is set to 100 Ω, and almost disappears when the resistance element is set to 300 Ω. In addition, when it is set to 200 Ω, block spots on the screen cannot be visually recognized. For this reason, block spots occur when the ratio of time constants from the display control substrate 40 to each gate drive module 22 is large, and it is considered that generation of block spots can be suppressed by reducing the ratio of constants at this time.

The wiring resistance from the display control substrate 40 to the closest gate driving module 22 or between the gate driving modules 22 is about 10 to 50?, And the resistance value of the resistance element 70 is larger than these values. By setting it as 100 ohms or more, the remarkable effect was acquired. In particular, by setting it as 200 ohms or more, the visible block stain was able to be lost. In other words, block unevenness is remarkably improved by setting the resistance value of the resistance element 70 to a value larger than the resistance value of the thin film wiring 41 for the gate-off voltage Vgl formed on the TFT substrate 10, preferably to a sufficiently large value. I know it becomes

According to the embodiment of the present invention, the resistance element 70 of the wiring resistance of the thin film wiring 41 or more is provided on the display control substrate 40, and the gate-off voltage Vgl from the gate-off power supply circuit 213 is provided through the resistance element. The TFT substrate 10 is supplied. For this reason, generation | occurrence | production of the block spot by the fluctuation | variation in the gate-off voltage Vgl for every gate drive module 22 can be suppressed or prevented.

(Example 2)

In the first embodiment, an example in which a resistor is provided on the display control substrate 40 and connected to the output terminal of the gate-off power supply circuit 213 has been described. In this embodiment, the resistor and the capacitor are the same. The case where (capacitor) is provided on the display control board 40 will be described.

Fig. 7 is a diagram showing an example of the configuration of main parts of the TFT display device according to the second embodiment of the present invention, and the TFT substrate of the liquid crystal display device and its control circuit are shown. In the figure, reference numeral 70 denotes a resistance element, 71 denotes a capacitor element.

The display control substrate 40 is provided with a resistance element 70 and a capacitor 71 and is connected to the output terminal of the gate-off power supply circuit 213. The resistance element 70 is connected in series with the gate drive module 22, and the capacitor 71 is connected in parallel with the gate drive module 22. In addition, the resistance element 70 is connected to the gate-off power supply circuit 213 side rather than the capacitor element 71.

In addition, the capacitor 71 is the sum of the input capacitance of the gate driving module 22 closest to the display control substrate 40 and the wiring capacitance of the gate power supply line (thin film wiring 41) to the gate driving module 22. It is made of larger capacity. More preferably, it consists of a capacity | capacitance which is sufficiently larger than the sum of the said capacity | capacitances.

For this reason, when the gate-off voltage Vgl fluctuates, the ratio of the time constant for each gate drive module 22 in the subsequent attenuation can be further reduced. Therefore, it is possible to suppress the gate off voltage Vgl from dynamically varying for each gate driving module 22, thereby more effectively suppressing or preventing block spots.

(Example 3)

In the first embodiment, the case where the resistance element 70 is provided on the display control substrate 40 has been described. In addition, in Example 2, the case where the resistance element 70 and the capacitance element 71 were provided was demonstrated. In contrast, in the present embodiment, a case where only the capacitor element is provided will be described.

Fig. 8 is a diagram showing an example of the configuration of main parts of the TFT display device according to the third embodiment of the present invention, and the TFT substrate of the liquid crystal display device and its control circuit are shown. The display control substrate 40 is provided with a capacitor 71 and is connected to the output terminal of the gate-off power supply circuit 213. The capacitor 71 is connected in parallel with the gate drive module 22.

In addition, the capacitor 71 has a capacity larger than the sum of the input capacitance of the gate driving module 22 closest to the display control substrate and the wiring capacitance of the gate power supply line (thin film wiring 41) to the gate driving module 22. More preferably, it consists of a capacity | capacitance large enough than the sum of the said capacity | capacitances.

Since there is an output resistance in the gate-off power supply circuit 213, by connecting the capacitor 71 to the output terminal thereof, the time constant for each gate driving module 22 at the time of attenuation after the variation of the gate-off voltage Vgl is attenuated. It is possible to reduce the ratio of and suppress block staining.

(Example 4)

In Examples 1 to 3, an example of the case where the TCP or COF gate driving module 22 composed of the insulating film 23 and the gate driving circuit 24 is used is described. In contrast, in the present embodiment, an example is described in which a semiconductor chip made of a gate driving circuit is mounted on a TFT substrate, and the semiconductor chip is used as a gate driving module.

Fig. 9 is a diagram showing an example of the configuration of main parts of the TFT display device according to the fourth embodiment of the present invention, and the TFT substrate of the liquid crystal display device and its control circuit are shown. In comparison with the case of FIG. 3, the configuration of the TFT substrate 17 is different.

The TFT substrate 17 is a semiconductor chip 25, 35 in which a gate driving circuit and a source driving circuit are not packaged. The TFT substrate 17 is provided at a peripheral portion other than the display region 16 on the glass substrate. Is called). For example, by attaching an adhesive ACF (Anisotropy Conductive Film) on the surface of the glass substrate and attaching a chip with gold bumps formed on the bottom thereof, the semiconductor chip is mechanically attached onto the TFT substrate 17 and at the same time. And the thin film wirings 41 and 42, the gate line input terminal 11i, and the source line input terminal 12i.

In other words, the semiconductor chip 25 is a gate drive module made of an integrated circuit formed on the TFT substrate 10, and the TFT display device can be further miniaturized and reduced in weight as compared with the case of using the gate drive module made of TCP. .

Since the gate driving voltage is supplied to the semiconductor chip 25 through the thin film wirings 41 and 42 on the TFT substrate 17, the time constant of each gate line is different for each semiconductor chip 25, and blocks are obtained as in the first to third embodiments. The problem is that staining occurs. Therefore, by providing the resistance element 70 on the display control substrate 40 or by providing the capacitor element 71 (not shown), block spots can be suppressed.

According to the present embodiment, even in the case of the TFT substrate 17 of the COG in which the semiconductor chip 25 as the gate driving circuit is directly attached on the glass substrate, the occurrence of block spots can be suppressed in the same manner as in the first to third embodiments. Can be.

(Example 5)

In Examples 1 to 4, examples of the case where the gate drive modules 22 and 25 are connected in series to the display control substrate 40 have been described. In contrast, in the present embodiment, a case where the gate drive modules are connected in parallel with each other will be described.

Fig. 10 is a diagram showing an example of the configuration of main parts of the TFT display device according to the fifth embodiment of the present invention, and the TFT substrate of the liquid crystal display device and its control circuit are shown. In comparison with the case of FIG. 9, the wirings between the semiconductor chips 25 on the TFT substrate 18 are different.

The thin film wiring 43 is branched on the TFT substrate 18 and connected to each semiconductor chip 25. In other words, the semiconductor chip 25 as the gate driving module is connected in parallel on the TFT substrate 18 by the thin film wiring 43, and the gate driving voltage is supplied from the display control substrate 40. FIG.

Since each semiconductor chip 25 has a different distance from the display control substrate 40, the time constant of each gate line 11 is also different for each semiconductor chip 25, and block spots are generated as in the first to third embodiments. Occurs. Therefore, by providing the resistance element 70 on the display control substrate 40 or by providing the capacitor element 71 (not shown), block spots can be suppressed.

According to the present embodiment, even in the case of the TFT substrate 18 in which the gate drive module 25 is connected in parallel, the occurrence of block spots can be suppressed as in the case of the first to fourth embodiments.

At this time, in each of the above embodiments, a liquid crystal display device having a specific structure and shape has been described as an example, but the present invention can be adapted to various TFT display devices. For example, if it is a display apparatus using a TFT substrate, it is not limited to a liquid crystal display apparatus. In addition, the TFT substrates 10 and 15 are not necessarily limited to glass substrates. 9 and 10, both the gate side and the source side are COG, but the gate side may be COG, and the source side may be TCP or COF.

According to the present invention, a TFT display device capable of performing uniform screen display can be provided at low cost. In addition, it is possible to provide a TFT display device which can suppress fluctuation in luminance due to fluctuation in gate driving voltage and can suppress or prevent block irregularities. In addition, it is possible to provide a TFT display device having high display quality and miniaturization and light weight at low cost.

Claims (9)

A TFT substrate having a plurality of gate lines formed on the insulating substrate, each gate line being drawn out to the periphery, and having a plurality of gate line input terminals formed thereon; Two or more gate driving modules connected to a plurality of gate line input terminals and controlling voltage supply timing for each gate line; A display control substrate for supplying a gate driving voltage to the gate driving module; At the periphery of the TFT substrate, a gate power supply line for transmitting a gate driving voltage from the display control substrate to the gate driving module is provided. The display control substrate has a gate power supply circuit for generating a gate drive voltage and a resistance element having a resistance value higher than the wiring resistance of the gate power supply line to the gate drive module closest to the display control board, And a gate driving voltage is supplied to the gate power supply line through the resistance element. The method of claim 1, The display control substrate has a capacitance element which is larger than the sum of the input capacitance of the gate driving module closest to the display control substrate and the wiring capacitance of the gate power supply line to the gate driving module, The capacitor display device is connected to the gate power supply line in parallel to the gate power supply line rather than the resistive element. The method of claim 1, And said gate power supply line is made of a conductive thin film formed on a TFT substrate. The method of claim 1, And the gate driving module is connected in series via a gate power supply line. The method of claim 1, The gate power supply line is branched on the gate driving module side rather than the resistor element. Each of the above gate drive modules is connected to a gate power supply line after branching, and is connected to each other in parallel. The method of claim 1, And the resistance element is provided at an output terminal of a gate-off power supply circuit for supplying a gate-off voltage for controlling the TFT to be in an off state. The method of claim 1, The gate driving module is made of an insulating film formed with a gate driving circuit, And a gate driving voltage is supplied to the gate driving circuit on the insulating film through the gate power supply line. The method of claim 7, wherein And said insulating film is connected in series to a display control substrate via said gate power supply line. The method of claim 1, And the gate driving module is formed of a semiconductor chip provided on a TFT substrate.