WO2008075480A1

WO2008075480A1 - Display driver, display driver unit, and display device

Info

Publication number: WO2008075480A1
Application number: PCT/JP2007/066089
Authority: WO
Inventors: Motomitsu Itoh
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-12-20
Filing date: 2007-08-20
Publication date: 2008-06-26

Abstract

The reverse phase input and feedback circuits of a preliminary output amplifier (12) provided within a source driver IC (3a) can be connected as an external circuit (12a) on a source board (4). An element constant of the external circuit (12a) is so set that the value of the output voltage of the spare output amplifier (12) becomes larger than that of the input voltage. This provides a display driver in which the load drive ability of the preliminary output amplifier can be set to a desired one.

Description

Specification

Display driver, display driver unit, and display device

Technical field

TECHNICAL FIELD [0001] The present invention relates to a display driver that enables driving using a spare wiring for a wiring defect of a display device.

Background art

[0002] A liquid crystal display device is disclosed in which a source line disconnected in a manufacturing process is repaired using a spare wiring before shipment of the product and can be driven.

FIG. 7 is a block diagram showing the configuration of such a liquid crystal panel described in Patent Document 1.

In this liquid crystal panel 1, the source line 110 extends from the source driver IC 131 of the source driver (source TAB) 102 into the display area 120 and from the gate driver IC 132 of the gate driver (gate TAB) 103. A gate line 111 extends into the display area 120, and thereby the pixel portion 113 is driven. Assuming that a disconnection 151 occurs in the source line 110, the display area is displayed from the source driver IC 131 via the compensation output buffer 136 in the source driver 102, the source substrate 104, the connection cable 125, and the gate substrate 105. A connection wiring 124 as a spare wiring arranged so as to extend to the opposite side of the source driver 102 with respect to 120 is welded by laser irradiation at the source line 110 and the connection point 152.

[0005] With this, for the source line 110 in which the disconnection point 151 occurs, the output from the normal output buffer 134 is not included in the portion from the normal output part 135 of the normal output buffer 134 of the source driver IC1 31 to the disconnection point 151. The signal is supplied from the connection point 152 to the disconnection point 151 by the output from the compensation output buffer 136 of the source driver IC 131. Reference numeral 106 denotes a control board, and reference numeral 126 denotes a flexible wiring board.

[0006] In Patent Document 1, in this way, the disconnected source line 110 is repaired so that it can be driven. [0007] In addition, Patent Documents 2 and 3 describe a configuration in which a source line is repaired using a spare wiring.

Patent Document 1: Japanese Published Patent Publication “JP 2003-202846 Publication (Publication Date: July 18, 2003)”

Patent Document 2: Japanese Patent Publication “JP-A-8-185144 (Publication Date: July 16, 1996)”

Patent Document 3: Japanese Patent Publication “JP-A-8-171081 (Publication Date: July 2, 1996)”

Disclosure of the invention

[0008] However, in the conventional configuration such as Patent Document 1, since the routing distance of the spare wiring is large, the signal supply to the source line via the spare wiring is different from the signal normally supplied to the source line. End up. For example, in FIG. 7, the connection wiring 124 from the compensation output portion 137 of the compensation output buffer 136 to the connection point 152 is very long through the source substrate 104, the connection cable 125, and the gate substrate 105. Therefore, a signal delay occurs due to the resistance and parasitic capacitance components in this path.

FIG. 8 shows a signal waveform A at the normal output unit 135 of the normal output buffer 134 and a signal waveform B at the connection point 152. The signal waveform A is a voltage rising waveform corresponding to the slew rate of the operational amplifier because the normal output buffer 134 is usually an output voltage waveform of a buffer composed of a voltage follower using an operational amplifier. The signal waveform at the compensation output section 137 of the compensation output buffer 136 is the same as the signal waveform A, but the signal waveform B depends on the resistance and parasitic capacitance components of the connection wiring 124 from the compensation output section 137 to the connection point 152. A signal delay occurs, resulting in a delayed voltage waveform. As the connection point 152 approaches the disconnection point 151, the voltage waveform further includes a delay due to the source line 110 itself rather than the signal waveform.

[0010] Therefore, in the source line 110 where the disconnection point 151 has occurred, each point of the portion from the normal output unit 135 to the disconnection point 151 of the normal output buffer 134 is shown in the signal waveform A and from the normal output unit 135. A voltage with a delay due to the source line 110 itself up to the point is supplied. This is a voltage waveform with a relatively fast rise. In addition, 151 stepped line In the generated source line 110, a voltage obtained by further adding a delay due to the source line 110 itself from the connection point 152 to the point is supplied to the signal waveform B at each point from the connection point 152 to the disconnection point 151. The This is a very slow voltage waveform.

[0011] The signal supply period tl for each source line 110 in one horizontal period is determined, and this is a sufficient time for charging the source line 110 to the target voltage V0 for the signal supply by the normal output. is there. However, when a signal is supplied via the connection wiring 124, the signal supply period tl ends before the voltage rises to the target voltage V0, the charging voltage becomes VI, and the source line 110 of that portion is There is a risk of insufficient charging. When charging is insufficient, display deterioration such as black lines on the display area occurs.

As described above, conventionally, an output amplifier that directly outputs a signal to the data signal line (source line), and a spare output amplifier that outputs a signal to the data signal line (source line) via the spare wiring, Therefore, if a signal is supplied using spare wiring to the data signal line where the disconnection has occurred, the load drive capability of the spare output amplifier will be insufficient and the data signal line (source line) will be insufficiently charged. There was a problem.

[0013] The present invention has been made in view of the above problems, and an object thereof is to realize a display driver capable of setting a load driving capability of a spare output amplifier to a desired one. . In addition, it is assumed that a display driver unit and a display device including the display driver are realized.

In order to solve the above problems, a display driver according to the present invention includes an output amplifier that outputs a signal to a data signal line of a display panel, and a preliminary output amplifier that is provided for the output amplifier. And a display driver circuit comprising: a display driver circuit comprising: a display driver circuit having at least one of a positive-phase input circuit, a negative-phase input circuit, and a feedback circuit from an output to a negative-phase input; It is characterized by having a connection part for connecting the external part for constituting at least a part of the external part using the external part.

[0015] According to the above invention, at least a part of at least one of the positive-phase input circuit, the negative-phase input circuit, and the feedback circuit from the output to the negative-phase input of the operational amplifier is externally connected. By making it possible to configure using parts, the output voltage of the spare output amplifier can be made larger than the input voltage to obtain a large load driving capability. This load driving capability can be made desired by selecting the external parts to be used.

[0016] As described above, there is an effect that it is possible to realize a display driver capable of setting the load driving capability of the auxiliary output amplifier to a desired one.

[0017] Further, when the output of the spare output amplifier having an increased load driving capability is connected to the spare wiring provided on the display panel for repairing the disconnected data signal line, the spare wiring is passed through the spare wiring. The power S is used to charge the data signal line to which the signal is supplied to the same voltage as the charging by the output amplifier.

[0018] Therefore, it is possible to realize a display driver that can avoid the occurrence of insufficient charging of the data signal line even if a signal is supplied to the data signal line in which the disconnection has occurred using the spare wiring. And! /, Has the effect.

In order to solve the above problems, the display driver of the present invention comprises a chip that incorporates the display driver circuit and is mounted on the display panel by COG (Chip On Glass). And a terminal connected to a wiring formed on the display panel as the connection portion.

[0020] According to the above invention, the load drive capability of the auxiliary output amplifier can be set to a desired value for the display driver in the form of COG.

In the display driver of the present invention, in order to solve the above-described problem, a wiring for connecting the external component is connected to the film from a chip incorporating the display driver circuit as the connection portion. It is characterized by being made up of extracted COF (Chip On Film).

[0022] According to the above invention, the load driving capability of the auxiliary output amplifier can be set to a desired value for the display driver in the form of COF.

In the display driver of the present invention, in order to solve the above-described problem, a wiring for connecting the external component is connected to the tape from the chip incorporating the display driver circuit as the connection portion. It is characterized by being composed of the extracted TCP (Tape Carrier Package). [0024] According to the above invention, the load drive capability of the auxiliary output amplifier can be set to a desired value for the display driver in the form of TCP.

In the display driver unit of the present invention, in order to solve the above-mentioned problem, the display driver and wiring for supplying a display drive signal to the display driver are formed, and the connection of the display driver is performed. A mounting portion for the external component connected to the section is provided! /, And a printed wiring board is provided! /.

[0026] According to the above invention, even if a signal is supplied to the data signal line in which the disconnection has occurred using the spare wiring, the external charging of the data signal line is insufficient by appropriately selecting and mounting the external parts. As a result, it is possible to realize a display driver unit that can avoid the occurrence of.

[0027] In order to solve the above problems, the display driver unit of the present invention includes the display driver and wiring for supplying a display drive signal to the display driver, and the connection of the display driver. And a printed wiring board on which the external component is mounted in a state of being connected to the unit! /.

[0028] According to the above invention, there is provided a display driver that can avoid the occurrence of insufficient charging of the data signal line even when a signal is supplied to the data signal line that has been disconnected using the spare wiring. There is an effect that it can be realized.

In the display driver unit of the present invention, in order to solve the above-described problem, the external component causes the spare output amplifier to output the output voltage of the spare output amplifier within the period of supplying the signal to the data signal line. It is characterized by a voltage that is greater than the input voltage of the output amplifier.

[0030] According to the above invention, there is an effect that the charging voltage of the data signal line using the auxiliary output amplifier can be made substantially equal to the charging voltage of the data signal line using the output amplifier.

In the display driver unit of the present invention, in order to solve the above-described problem, the external component causes the output voltage of the auxiliary output amplifier to be temporally changed with respect to a steady value of the output voltage of the auxiliary output amplifier. It is characterized by a vibrating waveform.

[0032] According to the above invention, the output voltage of the auxiliary output amplifier is supplied to the data signal line. By oscillating to a value larger than the steady value during the supply period, the load drive capability of the standby output amplifier can be easily increased.

In the display driver unit of the present invention, in order to solve the above problem, the external component includes a component having a variable element constant, and the length of a period during which the signal is supplied to the data signal line And an element constant control means for changing the element constant in response to the above.

[0034] According to the above invention, by changing the element constant of the external component by the element constant control means, the optimum output voltage of the standby output amplifier in accordance with the period for supplying the signal to the data signal line is obtained. There is an effect that it can be set.

[0035] In order to solve the above problems, the display device of the present invention includes the display driver unit, and a signal output to the selected data signal line is input to the input of the auxiliary output amplifier. The wiring connected to the output of the auxiliary output amplifier is formed so as to be connectable to one end of the data signal line on the side opposite to the display driver side.

[0036] According to the above invention, there is provided a display device capable of avoiding the occurrence of insufficient charging of the data signal line even if the signal supply is performed using the spare wiring for the data signal line in which the disconnection has occurred. If it can be realized, it will produce an effect.

In order to solve the above problems, the display device of the present invention is a liquid crystal display device.

[0038] According to the above invention, the liquid crystal display device using the spare wiring has an effect of avoiding insufficient charging of the data signal line.

[0039] Other objects, features, and advantages of the present invention will be fully understood from the following description. The advantages of the present invention will become apparent from the following description with reference to the accompanying drawings.

Brief Description of Drawings

FIG. 1, showing an embodiment of the present invention, is a block diagram showing a configuration of a display device

FIG. 2 is a diagram showing a specific example of a spare output amplifier. (A) shows a spare output amplifier connected with an external circuit. (B) is a graph showing the gain characteristics of the auxiliary output amplifier in (a).

(3) (a) and (b) are graphs showing the voltage waveforms when the standby output amplifier of Fig. 2 is used, (a) shows the attenuation waveform without vibration, and (b) shows the vibration waveform. Represents an attenuation waveform. 4] A block diagram showing a configuration for changing the element constant of the external circuit of the auxiliary output amplifier of FIG.

5) A waveform diagram showing the waveform of the signal used in the configuration of FIG. 4, where (a) shows the case where the horizontal sync signal is used, and (b) shows the case where the vertical sync signal and the data enable signal are used. is doing.

6] It is a plan view showing the form of the display driver. (A) shows the case of COG, (b) shows the case of COF, and (c) shows the case of TCP.

FIG. 7 is a block diagram showing a conventional technique and showing a configuration of a display device.

8] A graph showing a voltage waveform output to the source line of the display device of FIG. Explanation of symbols

1 Greed ¾ Display device (non-table device)

2 Display No Nenore

3 Source driver (display driver)

4 Source board (printed wiring board)

11 Output amplifier

12 Spare output amplifier

12a External circuit

21 Second spare wiring

SL source line (data signal line)

BEST MODE FOR CARRYING OUT THE INVENTION

One embodiment of the present invention is described below with reference to FIGS. 1 to 6.

FIG. 1 shows a configuration of a liquid crystal display device (display device) 1 according to the present embodiment.

[0044] The liquid crystal display device 1 includes a display panel 2, a plurality of source drivers 3, ..., a source substrate 4, a controller A roll board 5, a flexible wiring board 6, and a plurality of gate drivers 7 are provided.

The display panel 2 is provided with a plurality of gate lines (scanning signal lines) GL... And a plurality of source lines (data signal lines) SL-- '! In the display region 2a of the display panel 2, a pixel PIX is formed corresponding to each intersection of the gate line GL and the source line SL. Pixel PIX has TFT15 and liquid crystal capacitor 16. The gate of TFT15 is connected to gate line GL, the source of TFT15 is connected to source line SL, and the drain of TFT15 is connected to the pixel electrode which is one end of liquid crystal capacitor 16. Has been. The other end of the liquid crystal capacitor 16 is connected to a common electrode.

The source driver 3 outputs a signal for charging the liquid crystal capacitor 16 to the source line SL, and includes an output amplifier 11 corresponding to each source line SL. Here, the source driver 3 is provided in the form of COF (Chip On Film) or TCP (Tape Carrier Package), and is a display driver that generates a signal to be output to the source line SL ... on the film or tape. A source driver IC3a with a built-in circuit is mounted. The output amplifier 11 is formed in the source driver IC 3a, and comprises a voltage follower using an operational amplifier. In addition to this, a source such as a shift register, a level shifter, and a DA converter circuit is provided in the source dry IC 3a. In this embodiment, a spare output amplifier 12 is further provided as described later. .

The source drivers 3... Are supplied with various control signals and display data for deriving an output to the output amplifier 11. These control signals and display drive signals such as display data are supplied as a signal group sO from the controller 5a mounted on the control board 5. The signal group sO output from the controller 5a is supplied to the source board 4 via the flexible wiring board 6. The source substrate 4 supplies these signal groups sO to each source driver 3 through wiring provided on the source substrate 4 itself.

[0048] The gate drivers 7 ... supply a scanning signal to be applied to the gate of the TFT 15 of the pixel PIX to the gate lines GL .... Here, the gate driver 7 is provided in the form of COF or TCP, and the gate driver IC 7a for generating the scanning signal is mounted on the film or tape, and the source driver 3 of the display panel 2 is provided. On two sides orthogonal to the side It is attached. The left area of the display panel 2 is driven using the left gate driver 7... And the right area of the display panel 2 is driven using the right gate driver 7. Although not shown here, the supply signal to the gate driver 7 may be supplied from the control board 5 or may be supplied from the controller power provided in the middle.

[0049] The spare output amplifier 12 provided in the source driver IC 3a is a redundant amplifier provided preliminary to the output amplifier 11. The spare output amplifier 12 is configured using an operational amplifier, and its positive phase input terminal is connected to the first spare wiring 27. The first auxiliary wiring 27 is provided in the vicinity of the edge of the display panel 2 on the source drain 3 side, in parallel with the edge. In this case, one combination of the spare output amplifier 12 and the first spare wiring 27 is provided for each source driver 3! /, And any number of pairs of source drivers 3 may be provided.

The reverse-phase input circuit of the auxiliary output amplifier 12 and the feedback circuit from the output to the reverse-phase input are provided as an external circuit 12 a on the source substrate 4. The external circuit 12a will be described later. The output of the auxiliary output amplifier 12 is drawn out on the film or tape of the source driver 3 as a connection part for connecting the external circuit 12a, and further connected to the wiring on the source board 4 to be connected to the source board 4 Connected to external circuit 12a at point Q above

In addition, the output of the auxiliary output amplifier 12 drawn out on the source substrate 4 is connected to the second auxiliary wiring 21 at the point Q described above. The second spare wiring 21 is provided for each source driver 3 and crosses over the source driver 3 located at both ends of the source driver group from the source board 4 to the vicinity of the gate driver 7 side edge of the display panel 2. Further, the vicinity of the end side opposite to the source driver 3 side of the display panel 2 is provided in parallel to the end side. The second auxiliary wiring 21 connected to the auxiliary output amplifier 12 of the source driver 3... Provided in the left area of the display panel 2 bypasses the display area 2 by bypassing the left end side of the display panel 2. The second spare wiring 2 1 connected to the spare output amplifier 12 of the source driver 3 ··· which is routed to a position opposite to the source driver 3 ··· and to the right side area of the display panel 2 is Then, bypass the right edge side of the display panel 2 and be routed to the position facing the source driver 3 • ··· across the display area 2! [0052] The first spare wiring 27 and the second spare wiring 21 are wirings used to repair the disconnected source line SL when the source line SL is disconnected in the manufacturing stage of the liquid crystal display device 1. For example, in FIG. 1, when a disconnection point 25 occurs in the source line SL, the output of the output amplifier 11 of the source driver 3 connected to the source line SL is represented by a corresponding P as shown by a point P. 1Connect to spare wiring 27 by welding with a laser. Also, connect the end of the disconnected source line SL on the opposite side of the source driver 3 side to the second spare wiring 21 corresponding to the source driver 3, as indicated by the point R, by welding with the same laser. .

[0053] As a result, the portion of the disconnected source line SL from the output amplifier 11 to the disconnected portion 25 and the selected pixel connected thereto are charged by the output of the output amplifier 11, and the portion from the point R to the stepped portion is charged. The portion up to 25 and the selected pixel connected to the portion are charged by the output of the auxiliary output amplifier 12.

Here, the external circuit 12a connected to the auxiliary output amplifier 12 will be described in detail.

FIG. 2 (a) shows an example of a configuration in which the external circuit 12 a is connected to the auxiliary output amplifier 12. The positive phase input terminal of the auxiliary output amplifier 12 is connected to the point P in FIG. 1, and the output voltage Vin of the output amplifier 11 is inputted. A parallel circuit of a resistor R1 and a capacitor C is connected between the negative-phase input terminal of the auxiliary output amplifier 12 and GND, and this parallel circuit constitutes a negative-phase input circuit. In addition, a resistor R2 is inserted between the output terminal of the auxiliary output amplifier 12 and the negative phase input terminal, and this resistor R2 forms a feedback circuit from the output of the auxiliary output amplifier 12 to the negative phase input. ing. The output terminal of auxiliary output amplifier 12 is connected to point Q in Fig.1.

[0056] Since the external circuit 12a is not monolithically formed with the spare output amplifier 12 in the source driver IC 3a, the source driver IC 3a has a reverse-phase input terminal of the spare output amplifier 12 and an output terminal. Each drawing wiring force of the source driver 3 is drawn to the source substrate 4 across the film or tape. Then, it is connected to an external circuit 12a composed of a resistor Rl, a resistor R2, and a capacitor C mounted at a mounting location of an external component provided on the source substrate 4.

[0057] FIG. 2 (b) shows a spare output amplifier 12 in a state where the external circuit 12a having the above configuration is connected. Shows the frequency characteristics of the gain of the output voltage Vout with respect to the input voltage Vin. Curve E shows the characteristics without capacitance C, curve F shows the characteristics when capacitance C is small, and curve G shows the characteristics when capacitance C is large.

[0058] The curve E corresponds to a configuration in which the capacitor C is not provided in FIG. 2A, and the time change of the output voltage Vout after the input voltage Vin is input is shown in FIG. The curve Q shown in (a) of (represents the voltage at point Q). In this case, the input voltage Vin changes with time as shown by curve P (representing the voltage at point P), and curve Q rises at a lower slew rate than curve P, but Vout / Vin = l + (R2 / R1 ), The voltage at point P rises to V0 and stabilizes, while the voltage at point Q becomes higher than V0 within the signal supply period tl and then rises to VI and stabilizes. To do. This indicates that the load driving capability of the auxiliary output amplifier 12 has increased.

[0059] Then, the voltage waveform at point R, where the voltage waveform at point Q appears delayed by the resistance and parasitic capacitance of the second auxiliary wiring 21, is as shown by the curve R in FIG. 3 (a). . Accordingly, if the resistance values (element constants) of the resistors R1 and R2 are appropriately selected, the voltage at the point R is set at the end of the signal supply period tl to the source line SL as shown in FIG. The power can be almost equal to the voltage at point P, and the source line SL can be charged to approximately the same voltage at the point P side from the disconnection point 25 to the point P side at the disconnection point 25. be able to.

[0060] In the case of curve F and curve G, the output voltage of the auxiliary output amplifier 12 shows an overshoot as shown by the curve Q in FIG. 3 (b), and the settling characteristics of the auxiliary output amplifier 12 Then, the steady state expressed by Vout / Vin = l + (R2 / R1) is reached. At this time, the amount of overshoot increases as the value of capacitance C increases. Curve Q rises at a lower slew rate than curve P, but the voltage at point P rises to V0 and stabilizes, whereas the voltage at point Q is at the first overshoot within the signal supply period tl. It continues to rise when it is greater than V0, and then rises to a voltage greater than the steady state voltage V2. This indicates that the load driving capability of the auxiliary output amplifier 12 has increased.

[0061] Then, the voltage waveform at point R, where the voltage waveform at point Q appears delayed by the resistance and parasitic capacitance of the second auxiliary wiring 21, is as shown by curve R in Fig. 3 (b). Become. Therefore, resistor R1 If the resistance value (element constant) of resistor R2 is selected appropriately, as shown in Fig. 3 (b), at the end of signal supply period tl to source line SL, The voltage at point R can be made approximately equal to the voltage at point P, and the source line SL is charged at the same voltage from the disconnection point 25 to the point P side and from the disconnection point 25 to the point R side. The power S to do.

[0062] As can be seen from the description of (a) and (b) in FIG. 3, the source driver 3 can connect the external components constituting the external circuit 12a. Thus, the display driver can set the load driving capability of the auxiliary output amplifier 12 to a desired one.

[0063] Therefore, even if a signal is supplied from the source driver 3 to the source line SL where the disconnection has occurred using the second spare wiring 21, it is possible to avoid the occurrence of insufficient charging of the source line SL. it can.

[0064] In the case of Fig. 3 (b), the same input voltage Vin force can be obtained with an output voltage Vout larger than the steady state due to the overshoot of the curve Q. Therefore, in Fig. 3 (a), In order to obtain the same charging voltage as in the case, the ratio R2 / R1 can be smaller than in the case of Fig. 3 (a).

[0065] The external circuit 12a is a circuit that constitutes a reverse-phase input circuit of the auxiliary output amplifier 12 and a feedback circuit from the output to the negative-phase input, but is not limited thereto, and is not limited to this. Any circuit that constitutes at least a part of at least one of the 12 positive-phase input circuits, the negative-phase input circuit, and the feedback circuit may be used. That is, by connecting the external circuit 12a to the auxiliary output amplifier 12, at least a part of at least one of the positive phase input circuit, the negative phase input circuit, and the feedback circuit of the auxiliary output amplifier 12 is connected. What is necessary is just to comprise using external parts.

[0066] For example, in the circuit of FIG. 2A, the resistor R2 is a spare output amplifier in the source driver IC3a.

The resistor R1 and the capacitor C can be used as external parts constituting the external circuit 12a. Also, only the resistor R1, only the resistor R2, and only the resistor C can be used as external parts constituting the circuit 12a. Furthermore, the non-inverting amplifier having the positive phase input circuit may be configured such that the positive phase input circuit, the negative phase input circuit, and the feedback circuit are all external circuits 12a. [0067] Although the above voltage has been described by taking a positive polarity as an example, the negative voltage also has a rising edge in the description of positive polarity and an overshoot undershoot. The same effect can be obtained.

Next, a description will be given of a configuration in which the element constants of the elements used in the external circuit 12a described above can be adjusted.

[0069] If the resistor R2 is configured with a variable resistor, for example, an electronic volume, as shown in FIG. 3A, the resistance of the resistor R2 is controlled by the control signal si input to the resistor R2. By changing the value, the gain of the auxiliary output amplifier 12 can be changed. In this way, the rising speed of the curve Q in (a) and (b) of FIG. 3 can be changed, so that the optimum curve Q is adapted to the length of the signal supply period tl to the source line SL. Can be set.

In this case, in the liquid crystal display device 1 of FIG. 1, it is preferable to provide an ASI C (element constant control means) 31 for resistance value control on the source substrate 4. The resistance value control ASIC 31 receives information on the signal supply period tl from the signal group sO output from the control board 5, generates a control signal si according to the length of the signal supply period tl, and outputs it to the resistor R2. To do.

Here, assuming that the source driver 3 performs line-sequential driving and the signal supply period tl corresponds to one horizontal period, the horizontal synchronization signal HSYNC is used as information regarding the signal supply period tl. Can do. Figure 4 shows the configuration of the ASIC 31 for resistance control in this case.

The resistance value control ASIC 31 of FIG. 4 includes a counter unit 31a, a period calculation unit 31b, a lookup table 31c, and a control signal generation unit 31d.

[0073] The horizontal synchronizing signal HSYNC included in the signal group sO output from the controller board 5 and the clock signal CK generated from the crystal oscillation circuit 30 are input to the counter unit 31a.

. As shown in FIG. 5 (a), the counter unit 31a has one cycle of the horizontal synchronization signal HSYNC.

Then, the number of clock signals CK corresponding to a much smaller period is counted, and the count result N is input to the period calculation unit 31b.

[0074] The period calculation unit 31b calculates the length of one horizontal period (signal supply period tl) based on the input count result, and stores the calculation result (length of the signal supply period tl) in the lookup table 31c. Enter in. [0075] The lookup table 31c is stored in the memory of the resistance value control ASIC 31 in advance, and describes the correspondence between the length of one horizontal period and the resistance value to be set in the resistor R2. . The lookup table 31c inputs a signal k related to resistance value information corresponding to the input calculation result of the length of one horizontal period to the control signal generation unit 31d.

[0076] The control signal generation unit 31d generates a control signal si corresponding to the input signal k and inputs the control signal si to the resistor R2.

[0077] In the above configuration, the length of one horizontal period is calculated from the period of the horizontal synchronization signal HSYNC. However, the present invention is not limited to this, and the vertical synchronization signal VSYNC as shown in (b) of FIG. It may be calculated from the cycle or the cycle of the data DATA enable signal ENA.

In the above configuration, the resistance value control ASIC 31 is provided not only on the source board 4 but also on the control board 5! /, May! /.

[0079] Further, in the above configuration, the resistance value of the resistor R2 is variable.

The element constant of any element constituting 12a can be made variable.

Heretofore, the configuration of the liquid crystal display device 1 according to the present embodiment has been described.

In FIG. 1, it has been described that the source driver 3 is configured by COF or TCP. When the source driver 3 is composed of COF, the source driver IC3a chip is mounted on the film 41 as shown in FIG. 6 (b), and the spare output amplifier 12 of the source driver 3 is directed from the source driver IC3a to the film 41. Wiring 35 is drawn out as a connection part for connecting external parts constituting the external circuit 12a. When the source driver 3 is configured by TCP, the source driver IC3a chip is mounted on the tape 42 as shown in FIG. 6 (c), and the spare output amplifier 12 is directed from the source driver IC3a to the tape 42. Wiring 35 is drawn out as a connecting portion for connecting external parts constituting the external circuit 12a.

On the other hand, as shown in FIG. 6 (a), unlike FIG. 1, the source driver IC3a chip can be mounted on the display panel 2 in the form of COG (Chip On Glass). . In this case, the source driver IC 3a has a terminal as a connection portion connected to the wiring 35 formed on the display panel 2 for connecting an external component constituting the external circuit 12a. The In this case, the external circuit 12a may be connected on the source substrate 4 directly connected to the display panel 2. [0083] In any of (a) to (c) of FIG. 6, the number of wirings 35 is the same as that of the external circuit 12a, the positive-phase input circuit, the negative-phase input circuit, and the feedback circuit of the auxiliary output amplifier 12. Because it depends on which part of the circuit it is, it is not limited to the two shown!

Further, in the present embodiment, the configuration composed of the source drivers 3... And the source substrate 4 can be handled as one display driver unit. In addition, the display driver unit further includes other components such as a control board 5 and a flexible wiring board 6! /. In addition, the display driver unit is provided with a place where the external circuit 12a is mounted, and may exist in a state before the external circuit 12a is mounted. In this case, a person who intends to manufacture a display device using this display driver unit selects and mounts external components appropriately, and adjusts the data signal line according to the display device to be manufactured. It is possible to avoid the occurrence of insufficient charging.

[0085] As the display panel and display device, in addition to the liquid crystal, for example, an organic EL element, a dielectric liquid, an electrochromic device, or the like may be used as the display element.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

[0087] As described above, the display driver of the present invention includes at least one of the positive-phase input circuit, the negative-phase input circuit, and the feedback circuit from the output to the negative-phase input of the operational amplifier. Both of them have a connection part for connecting the external parts for constituting a part using the external parts.

As described above, there is an effect that it is possible to realize a display driver capable of setting the load driving capability of the auxiliary output amplifier to a desired one.

[0089] The specific embodiments or examples made in the detailed description section of the invention have so far clarified the technical contents of the present invention. Within the spirit of the present invention, which should not be construed in a narrow sense, limited to examples only, and within the scope of the claims described below! It is something that can be done.

Industrial applicability

[0090] The present invention relates to a high-definition, large-screen liquid crystal display device in which the occurrence probability of disconnection is high, It can be preferably used.

Claims

The scope of the claims

[1] A display comprising a display driver circuit having an output amplifier that outputs a signal to a data signal line of a display panel, and an operational amplifier for configuring a spare output amplifier that is preliminarily provided for the output amplifier In the driver

The at least one part of the operational amplifier of the positive phase input circuit, the negative phase input circuit, and the feedback circuit from the output to the negative phase input is configured by using an external component. A display drain having a connecting portion for connecting an external component.

[2] The chip is mounted on the display panel by COG (Chip On Glass) and includes the display driver circuit. The chip is connected to a wiring formed on the display panel to connect the external component. 2. The display driver according to claim 1, wherein a terminal is provided as the connection portion.

[3] A wiring for connecting the external component is configured as a COF (Chip On Film) drawn out from a chip incorporating the display driver circuit onto a film as the connection portion. The display driver according to claim 1, wherein the display driver is characterized.

[4] The wiring for connecting the external component is configured as a TCP (Tape Carrier Package) drawn out from the chip having the display driver circuit toward the tape as the connection portion. The display driver according to claim 1, wherein the display driver is characterized.

[5] Any one of claims 1 to 4, the display driver according to claim 1,

A wiring for supplying a display drive signal to the display driver is formed, and a mounting portion for the external component connected to the connection portion of the display driver is provided! A display driver unit characterized by comprising! /.

[6] Any one of claims 1 to 4, the display driver according to claim 1,

A wiring for supplying a display driving signal to the display driver is formed, and a printed wiring board on which the external component is mounted in a state of being connected to the connection portion of the display driver. A display driver unit characterized by that.

[7] The external component may be configured such that the output voltage of the spare output amplifier is higher than the input voltage of the spare output amplifier during a period in which the signal is supplied to the data signal line. The display driver unit according to claim 6, wherein

[8] The external component has a waveform that causes the output voltage of the auxiliary output amplifier to oscillate in time with respect to a steady value of the output voltage of the auxiliary output amplifier. The display driver unit described in the section.

[9] The external component includes a component whose element constant is variable,

9. The device according to any one of claims 6 to 8, further comprising element constant control means for changing the element constant according to a length of a period during which the signal is supplied to the data signal line. Or the display driver unit described in item 1.

[10] The display driver unit according to paragraph 1 is provided with any force from claims 5 to 9,

A signal to be output to the selected data signal line is input to the input of the spare output amplifier,

A display device, wherein a wiring connected to an output of the auxiliary output amplifier is formed so as to be connectable to one end of the data signal line opposite to the display driver side.

11. The display device according to claim 10, which is a liquid crystal display device.