JP4700190B2 - Image display device and driving method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
[0002]
The present invention relates to an image display apparatus (active matrix image display apparatus) that displays information such as video by switching elements and pixels arranged in a matrix, and more particularly to a digital driving method and the image display apparatus.
[0003]
[Prior art]
Recently, a technique for manufacturing a semiconductor device in which a semiconductor thin film is formed on an inexpensive glass substrate, for example, a thin film transistor (TFT) has been rapidly developed. This is because the demand for an active matrix liquid crystal display device, which is a kind of active matrix image display device, has increased.
[0004]
In addition, active matrix light-emitting devices (hereinafter referred to as light-emitting devices), which are a kind of active matrix image display devices using self-light-emitting light-emitting elements, have been actively researched. In this specification, an EL element or the like is shown as a light-emitting element. The light-emitting element includes a layer containing an organic compound (hereinafter referred to as an organic compound layer) from which luminescence (Electro Luminescence) generated by applying an electric field is obtained, an anode layer, and a cathode layer. Luminescence in organic compounds includes light emission (fluorescence) when returning from the singlet excited state to the ground state and light emission (phosphorescence) when returning from the triplet excited state to the ground state. May be.
[0005]
Hereinafter, an active matrix liquid crystal display device will be described as an example as a typical example of an active matrix image display device.
[0006]
As shown in FIG. 40, the active matrix liquid crystal display device includes a source signal line drive circuit 101, a gate signal line drive circuit 102, and a pixel array unit 103 arranged in a matrix. The source signal line driver circuit 101 samples an input video signal in synchronization with a timing signal such as a clock signal and writes data to each source signal line 104. The gate signal line driver circuit 102 sequentially selects the gate signal lines 105 in synchronization with the timing of the clock signal or the like, and controls on / off of the TFTs 106 that are switching elements in each pixel of the pixel array unit 103. It has become. As a result, data written to each source signal line 104 is sequentially written to each pixel.
[0007]
There are an analog method and a digital method as a driving method of the source signal line driver circuit, and a digital active matrix liquid crystal display device capable of high-definition and high-speed driving has been attracting attention.
[0008]
A conventional digital source signal line driving circuit is shown in FIG. In FIG. 41, reference numeral 201 denotes a shift register unit, which is composed of a shift register basic circuit 202 including a flip-flop circuit and the like. When the start pulse SP is input to the shift register unit 201, sampling pulses are sequentially sent to the latch 1 circuit 203 (LAT1) in synchronization with the clock signal CLK.
[0009]
The latch 1 circuit 203 (LAT1) sequentially stores n-bit (n is a natural number) digital video signals supplied from the data bus line DATA in synchronization with the sampling pulse from the shift register unit.
[0010]
After a signal for one horizontal pixel is written to the LAT1 group, the signal held in each latch 1 circuit 203 (LAT1) is latched in synchronization with the latch pulse transmitted from the latch signal bus line LP. (LAT2) is sent all at once and written.
[0011]
When the digital video signal is held in the latch 2 circuit 204 (LAT2), the start pulse SP is input again, and the digital video signal for the pixel in the next row is newly written into the LAT1 group. At this time, the LAT2 group stores digital video signals for the pixels in the previous row, and the D / A conversion circuit 205 (digital / analog signal conversion circuit) converts an analog video signal corresponding to the digital video signal to each source. It is written to the signal line.
[0012]
In order to drive the liquid crystal display device, a so-called AC driving method is applied in which a voltage whose polarity is inverted every frame is applied to the liquid crystal in order to improve reliability. In this AC driving method, in order to prevent the occurrence of flicker, gate line inversion driving for inverting the polarity of the voltage written to the source signal line for each gate signal line, or source for writing the voltage with the polarity inverted for each source signal line There are line inversion driving and dot inversion driving for writing a voltage whose polarity is inverted in units of one pixel in the horizontal and vertical directions.
[0013]
In FIG. 41, two systems of a plurality of gradation power supply lines supplied to the D / A conversion circuit 205 are shown. Vref (+) is a gradation power supply line for outputting a positive polarity and Vref (−) is a negative polarity for outputting from a D / A conversion circuit. 41, the first source signal line SL1 has a positive polarity voltage, the second source signal line SL2 has a negative polarity voltage, and the third source signal line SL3 has a negative polarity. A voltage having a positive polarity is applied to the fourth source signal line SL4, and a voltage having a negative polarity is applied to the fourth source signal line SL4. Note that if the polarity of the power supply voltage of the gradation power supply line is inverted every frame in this state, the source signal line driving circuit shown in FIG. 41 performs source line inversion driving. If the polarity of the power supply voltage of the gradation power supply line is inverted for each gate signal line, the source signal line driving circuit shown in FIG. 41 performs dot inversion driving.
[0014]
Unlike FIG. 41, gate line inversion drive is performed if the polarity of the power supply voltage of the grayscale power supply line is inverted for each gate signal line only by inputting one system of grayscale power supply line (not shown). .
[0015]
[Problems to be solved by the invention]
Each of the D / A conversion circuits in FIG. 41 drives one source signal line. However, when creating a high-resolution, high-definition liquid crystal display device, making the same number of D / A conversion circuits occupying a large area as the number of source signal lines is an obstacle to miniaturization of the liquid crystal display device which has been desired in recent years. Japanese Patent Laid-Open No. 11-167373 proposes a method of driving a plurality of source signal lines with a single D / A conversion circuit.
[0016]
FIG. 42 shows a configuration example of a source signal line driver circuit that drives four source signal lines with one D / A conversion circuit. 42, a parallel / serial conversion circuit 301 (P / S conversion circuit), a source line selection circuit 302, and a selection signal (SS) input thereto are newly added to FIG. . Despite the addition of such a circuit, if the four source signal lines can be driven by one D / A converter circuit, the effect of reducing the number of necessary D / A converter circuits to ¼ is great. The area occupied by the signal line driver circuit can be reduced.
[0017]
Even in the method of driving a plurality of source signal lines with such a single D / A conversion circuit, it is necessary to perform AC driving of the liquid crystal as described above. According to the conventional concept, each D / А conversion circuit always outputs the same polarity for at least one horizontal writing period. Therefore, in the method of driving a plurality of source signal lines with one D / A conversion circuit, gate line inversion driving and frame inversion driving are employed as AC driving of liquid crystal.
[0018]
Here, a problem in performing source line inversion driving and dot inversion driving based on the conventional concept by a method of driving a plurality of source signal lines with one D / A conversion circuit will be described with reference to FIG. explain. FIG. 43 shows a specific example in which four source signal lines are driven by one D / A conversion circuit. Here, when the grayscale power supply lines are connected to adjacent D / A conversion circuits so that the polarities of the outputs from those D / A conversion circuits are inverted as in FIG. 41, every four source signal lines are provided. The polarity is reversed to complete source line inversion driving. Similarly, it is not perfect dot inversion driving. This is not enough if you want high image quality. As described above, when a plurality of source signal lines are driven by one D / A conversion circuit, it is necessary to construct a new driving method in order to perform the source line inversion driving method and the dot inversion driving method.
[0019]
Accordingly, the present invention provides a driving method thereof.
[0020]
[Means for Solving the Problems]
In the first driving method of the present invention, in order to obtain outputs with different polarities from the D / A converter circuit, two systems of gradation power supply lines are supplied to the source signal line driver circuit, A gradation power supply having a switch (hereinafter referred to as a connection changeover switch) for switching connection between two systems of gradation power supply lines and connected to each D / A conversion circuit by a control signal input to the connection changeover switch It is characterized by switching lines and performing source line inversion driving and dot inversion driving.
[0021]
Hereinafter, for convenience of explanation in this specification, a gradation power supply line that can be output with a positive polarity by being connected to a D / A conversion circuit is referred to as “a gradation power supply line for a positive polarity output”, and conversely a negative polarity. A gray scale power supply line that can obtain the output of is expressed as a "tone power supply line for negative polarity output". In addition, a voltage is applied to each gradation power line connected to the D / A conversion circuit so that a positive polarity output can be obtained from the D / A conversion circuit. To supply. " Similarly, a voltage is applied to each gradation power line connected to the D / A conversion circuit so that a negative polarity output can be obtained from the D / A conversion circuit. "Supply to the line."
[0022]
Each gradation power supply line for positive polarity output and each gradation power supply line for negative polarity output have a relationship in which the power supply voltage of the corresponding gradation power supply line is inverted in polarity. Therefore, if the polarity of the power supply voltage of all the gradation power supply lines is reversed, the same role as that of the other gradation power supply line is assumed.
[0023]
To perform source line inversion driving with the configuration of the first driving method, the following is performed. During each gate signal line selection period of a certain frame period, the odd-numbered source signal line is selected by connecting the gradation power supply line for positive polarity output to the D / A converter circuit and selecting the even-numbered source signal line. During this period, the gradation power supply line for negative polarity output is connected to the D / A conversion circuit. During each gate signal line selection period in the next frame period, during the period for selecting the odd-numbered source signal line, the gradation power supply line for negative polarity output is connected to the D / A conversion circuit, and the even-numbered source signal line is selected. During this period, the positive polarity output gradation power supply line is connected to the D / A conversion circuit. As described above, the source line inversion drive can be performed by controlling the control signal of the connection changeover switch.
[0024]
In particular, in the above driving method, by combining the period for selecting the odd-numbered source signal lines or the period for selecting the even-numbered source signal lines into a certain period of each gate signal line selection period, The cycle of the control signal can be lengthened, and the circuit operation burden can be reduced at the same time.
[0025]
In order to perform dot inversion driving with the configuration of the first driving method, the following is performed. During an odd-numbered gate signal line selection period of a certain frame period, a positive polarity output grayscale power supply line is connected to the D / A conversion circuit during an odd-numbered source signal line selection period, and an even-numbered source signal line During the period for selecting the negative polarity output gradation power supply line is connected to the D / A conversion circuit. During the even-numbered gate signal line selection period of the same frame period, the gradation power supply line for negative polarity output is connected to the D / A conversion circuit during the period of selecting the odd-numbered source signal line, and the even-numbered source signal line During the period for selecting, the gradation power supply line for positive polarity output is connected to the D / A conversion circuit. Further, during the odd-numbered gate signal line selection period of the next frame period, the gradation power supply line for negative polarity output is connected to the D / A conversion circuit during the period for selecting the odd-numbered source signal line, and the even-numbered source signal In the period for selecting the line, the gradation power supply line for positive polarity output is connected to the D / A conversion circuit. During the even-numbered gate signal line selection period in the same frame period, the odd-numbered source signal line is selected by connecting the gradation power supply line for positive polarity output to the D / A conversion circuit, and the even-numbered source signal line. During the period for selecting the negative polarity output gradation power supply line is connected to the D / A conversion circuit. As described above, dot inversion driving can be performed by controlling the control signal of the connection changeover switch.
[0026]
In particular, in the above driving method, the connection switching is performed by separating the period for selecting the odd-numbered source signal lines and the period for selecting the even-numbered source signal lines into the first half and the second half of each gate signal line selection period. The cycle of the control signal of the switch can be lengthened, and the circuit operation burden can be reduced at the same time.
[0027]
In the second driving method of the present invention, unlike the first method, one gray scale power supply line is supplied to the source signal line drive circuit and directly connected to each D / A conversion circuit. Source line inversion driving and dot inversion driving are performed by inverting the polarity of the power supply voltage of the line.
[0028]
In order to perform source line inversion driving with the configuration of the second driving method, the following is performed. During each gate signal line selection period of a certain frame period, the positive polarity output voltage is supplied to the gradation power supply line during the period when the odd-numbered source signal line is selected, and negative polarity during the period when the even-numbered source signal line is selected. An output voltage is supplied to the gradation power supply line. During each gate signal line selection period of the next frame period, the negative polarity output voltage is supplied to the gradation power supply line during the period for selecting the odd-numbered source signal line, and the positive polarity for the period for selecting the even-numbered source signal line. An output voltage is supplied to the gradation power supply line. As described above, the source line inversion drive can be performed by inverting the polarity of the power supply voltage of the gradation power supply line.
[0029]
In particular, even in the above driving method, the gradation power supply line can be obtained by combining the period for selecting the odd-numbered source signal lines or the period for selecting the even-numbered source signal lines into a certain period of each gate signal line selection period. The cycle in which the polarity of the power supply voltage is inverted can be lengthened, and the circuit operation burden can be reduced at the same time.
[0030]
Further, in order to perform dot inversion driving with the configuration of the second driving method, the following is performed. During an odd-numbered gate signal line selection period of a certain frame period, a period for selecting an odd-numbered source signal line supplies a positive polarity output voltage to the gradation power supply line, and a period for selecting an even-numbered source signal line A negative polarity output voltage is supplied to the gradation power supply line. During the even-numbered gate signal line selection period of the same frame period, the period for selecting the odd-numbered source signal line supplies the negative polarity output voltage to the gradation power supply line, and the period for selecting the even-numbered source signal line A positive polarity output voltage is supplied to the gradation power supply line. Further, during the odd-numbered gate signal line selection period of the next frame period, the period for selecting the odd-numbered source signal line is the period for supplying the negative polarity output voltage to the gradation power supply line and selecting the even-numbered source signal line. Supplies a positive polarity output voltage to the gradation power supply line. During the even-numbered gate signal line selection period of the same frame period, the period for selecting the odd-numbered source signal line supplies the positive polarity output voltage to the gradation power supply line, and the period for selecting the even-numbered source signal line A negative polarity output voltage is supplied to the gradation power supply line. As described above, it is possible to perform dot inversion driving by inverting the polarity of the power supply voltage of the gradation power supply line.
[0031]
In particular, also in the driving method described above, the period for selecting the odd-numbered source signal lines and the period for selecting the even-numbered source signal lines are separated into the first half and the second half of each gate signal line selection period, so The cycle in which the polarity of the power supply voltage of the power supply line is reversed can be lengthened, and the circuit operation burden can be reduced at the same time.
[0032]
In the third driving method of the present invention, two gray scale power supply lines are supplied to the source signal line driving circuit in order to obtain outputs with different polarities from the D / A conversion circuit as in the first method. However, a plurality of source signal lines connected to each D / A conversion circuit are grouped together as either odd-numbered or even-numbered. The first system gradation power supply line is connected to each D / A conversion circuit connected to the odd-numbered source signal line, and each D / A conversion circuit connected to the even-numbered source signal line is connected to each D / A conversion circuit. A source line inversion drive and a dot inversion drive are performed by connecting the second-level gradation power supply line and periodically reversing the polarity of the power supply voltage of all the gradation power supply lines.
[0033]
In order to perform source line inversion driving with the configuration of the third driving method, the following is performed. During a certain frame period, a positive polarity output voltage is supplied to the first system gradation power supply line, and a negative polarity output voltage is supplied to the second system gradation power supply line. During the next frame period, a negative polarity output voltage is supplied to the first system gradation power supply line, and a positive polarity output voltage is supplied to the second system gradation power supply line. As described above, the source line inversion drive can be performed by applying the power supply voltage to the gradation power supply line.
[0034]
Further, in order to perform dot inversion driving with the configuration of the third driving method, the following is performed. During the odd-numbered gate signal line selection period of a frame period, a positive polarity output voltage is supplied to the first system gradation power supply line, and a negative polarity output voltage is supplied to the second system gradation power supply line. To do. During the even-numbered gate signal line selection period in the same frame period, a negative polarity output voltage is supplied to the first system gradation power supply line, and a positive polarity output voltage is supplied to the second system gradation power supply line. To do. Further, during the odd-numbered gate signal line selection period of the next frame period, a negative polarity output voltage is supplied to the first system gradation power supply line, and a positive polarity output voltage is applied to the second system gradation power supply line. Supply. During the even-numbered gate signal line selection period in the same frame period, a positive polarity output voltage is supplied to the first system gradation power supply line, and a negative polarity output voltage is supplied to the second system gradation power supply line. To do. As described above, dot inversion driving can be performed by applying a power supply voltage to the gradation power supply line.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0036]
[Embodiment 1]
In this embodiment, in order to obtain outputs with different polarities from the D / A conversion circuit, two independent grayscale power supply lines are supplied to the source signal line drive circuit, and each D / A conversion circuit and 2 are connected by a connection changeover switch. One method for enabling source line inversion and dot inversion driving by switching the connection to the system gradation power supply line will be described.
[0037]
In the present embodiment, as an embodiment in which an even number of source signal lines are driven by one D / A conversion circuit, four source signal lines are driven and (n + 1) -bit (n is an integer of 0 or more) digital video signal. A case corresponding to an input will be described as an example.
[0038]
FIG. 1 shows a schematic circuit diagram of this embodiment. In FIG. 1, a shift register unit that generates sampling pulses for sequentially sampling digital video signals, a latch 1 circuit unit that latches digital video signals by the sampling pulses, and a latch 1 circuit unit that receives latch pulses. The latch 2 circuit portion that latches the stored digital video signals all at once is omitted. The parallel / serial conversion circuit (P / S conversion circuit) outputs parallel output data (D0 [4k + 1] to Dn [4k + 1], D0 [4k + 2] to Dn [4k + 2]) of the two latch circuits. , D0 [4k + 3] to Dn [4k + 3] and D0 [4k + 4] to Dn [4k + 4] (k is an integer equal to or greater than 0)) are converted into serial data. Here, D0 [4k + 1] represents the digital video signal of the least significant (first) bit (LSB) for the (4k + 1) th source signal line, and Dn [4k + 1] is also the (4k + 1) th. ) A digital video signal of the most significant ((n + 1)) th bit (MSB) with respect to the source signal line. Hereinafter, the notation Di [s] represents the (i + 1) -th bit digital video signal for the s-th source signal line.
[0039]
Reference numeral 100a denotes a connection changeover switch for switching the connection between the two systems of gradation power supply lines Vref1 and Vref2 and the D / A conversion circuit, which is connected to either one by a changeover control signal SVr. Here, it is assumed that the D / A conversion circuit connected to Vref1 outputs a positive polarity and the D / A conversion circuit connected to Vref2 outputs a negative polarity among the two systems of gradation power supply lines. For convenience, in this specification, the connection changeover switches 100a and 100b (shown in FIG. 3) are connected to the lower terminal when SVr is Hi, and are connected to the upper terminal when SVr is Lo. The present invention is not limited to the circuit configuration of the connection changeover switch, and can be applied to any circuit that performs the same operation.
[0040]
The source line selection circuit includes four switches sw1, sw2, sw3, and sw4. When sw1 is turned on, the (4k + 1) th source signal line is connected to the output of each D / A conversion circuit, and when sw2 is turned on. The (4k + 2) th source signal line is connected to the output of each D / A converter circuit. When sw3 is turned on, the (4k + 3) th source signal line is connected to the output of each D / A converter circuit. When sw4 is turned on, the (4k + 4) th source signal line is connected to the output of each D / A conversion circuit. SS1 to SS4 are selection signals for controlling on / off of sw1 to sw4, respectively.
[0041]
The signal operation timing of FIG. 1 is shown in FIG. One gate signal line selection period is divided into four, SS1 is set to Hi level and sw1 is turned on in the first period, SS2 is set to Hi level and sw2 is turned on in the second period, and the third period Fig. 5 shows an operation of setting SS3 to Hi level and turning on sw3, and setting SS4 to Hi level and turning on sw4 in the fourth period. The output of each bit data of each P / S conversion circuit is synchronized with the above selection signals (SS1 to SS4), the gate signal line selection period is divided into four, and the first (4k) +1) The source signal line data is output, the (4k + 2) source signal line data is output during the second period, and the (4k + 3) source signal line is output during the third period. Is controlled by the selection signal SS input to the P / S conversion circuit so that the data of the (4k + 4) th source signal line is output in the fourth period. In this way, the digital video signal corresponding to each source signal line is reflected in the writing of an appropriate source signal line. This state is shown in D0_1 to Dn_1 and D0_5 to Dn_5 in FIG. Here, Di_1 is output data of the (i + 1) th bit of the left P / S conversion circuit in FIG. 1, and Di_5 is output data of the (i + 1) th bit of the right P / S conversion circuit in FIG. It is. In FIG. 2, Di [s, g] indicates the (i + 1) -th bit data for the pixel in the s-th column and the g-th row, and the gate signal line information is added to the notation Di [s]. Is. (Hereafter, the notation Di [s, g] has the same meaning)
[0042]
Next, it is shown that source line inversion and dot inversion driving can be performed by the method of inputting the gradation power supply line switching control signal SVr to the D / A conversion circuit.
[0043]
The input signal of the control signal SVr when performing source line inversion driving is indicated by SVr (s) and SVr (sb) in FIG. Here, SVr (sb) indicates the control signal SVr in the next frame period when SVr (s) is input, and is an inverted signal of SVr (s). As a result, the polarity written in each pixel is as shown in FIG.
[0044]
Further, the method of inputting the control signal SVr when performing dot inversion driving is shown in SVr (d) and SVr (db) in FIG. Here, SVr (db) represents the control signal SVr in the next frame period when SVr (d) is input, and is an inverted signal of SVr (d). As a result, the polarity written to each pixel is as shown in FIG.
[0045]
As described above, according to this embodiment, even when four source signal lines are driven by one D / A conversion circuit, the source line inversion driving method and the dot inversion driving method can be performed. In this embodiment, the case where four source signal lines are driven by one D / A conversion circuit is described as an example. However, the present invention is not limited to this, and two, four lines are used. The present invention can also be applied to a case where an even number of source signal lines such as... Are driven by one D / A conversion circuit.
[0046]
[Embodiment 2]
In this embodiment, in order to obtain an output having a different polarity from the D / A converter circuit as in the first embodiment, two gradation power supply lines are supplied to the source signal line drive circuit, and each D / A conversion is performed by the connection switch. Another method for enabling source line inversion and dot inversion driving by switching the connection between a circuit and two gradation power supply lines will be described.
[0047]
In the present embodiment, an odd number of source signal lines are driven by one D / A conversion circuit, and three source signal lines are driven, and (n + 1) -bit (n is an integer of 0 or more) digital video signal. A case corresponding to an input will be described as an example.
[0048]
FIG. 3 shows a schematic circuit diagram of the present embodiment. In FIG. 3, the shift register unit, the latch 1 circuit unit, and the latch 2 circuit unit are omitted as in FIG. The parallel / serial conversion circuit (P / S conversion circuit) outputs parallel output data (D0 [3k + 1] to Dn [3k + 1], D0 [3k + 2] to Dn [3k + 2] of the two latch circuits. , D0 [3k + 3] to Dn [3k + 3] (k is an integer equal to or larger than 0)) are converted into serial data by each bit.
[0049]
Here, it should be noted that the connection switching switch 100b for switching the connection between the D / A conversion circuit and the gradation power supply lines Vref1 and Vref2 has a different connection method to the gradation power supply line. As shown in FIG. 3, the two adjacent connection changeover switches 100b are reversely connected to the two gradation power supply lines Vref1 and Vref2. Since each connection changeover switch 100b is controlled by the same control signal SVr, adjacent D / A conversion circuits are always connected to the gradation power supply line for reverse polarity output at the same time. Reflecting this, the outputs of adjacent D / A conversion circuits always have opposite polarities at the same time. Therefore, unlike the first embodiment, even when three source signal lines are driven by one D / A conversion circuit, it is possible to write a potential whose polarity is inverted to adjacent source signal lines.
[0050]
Note that the same result can be obtained even if the operation of the adjacent connection changeover switch is reversed without changing the connection method of the adjacent connection changeover switch 100b with the gradation power supply line as described above.
[0051]
The source line selection circuit includes three switches sw1, sw2, and sw3. When sw1 is turned on, the (3k + 1) th source signal line is connected to the output of each D / A conversion circuit, and when sw2 is turned on, The 3k + 2) th source signal line is connected to the output of each D / A conversion circuit. When sw3 is turned on, the (3k + 3) th source signal line is connected to the output of each D / A conversion circuit. . SS1 to SS3 are selection signals for controlling on / off of sw1 to sw3, respectively.
[0052]
The signal operation timing of FIG. 3 is shown in FIG. One gate signal line selection period is divided into three, SS1 is set to Hi level and sw1 is turned on in the first period, SS2 is set to Hi level and sw2 is turned on in the second period, and the third period Shows the operation of setting SS3 to Hi level and turning on sw3. The output of each bit data of each P / S conversion circuit is synchronized with the selection signal (SS1 to SS3), the gate signal line selection period is divided into three, and the first (3k) +1) The source signal line data is output, the (3k + 2) source signal line data is output in the second period, and the (3k + 3) source signal line is output in the third period. Is controlled by the selection signal SS input to the P / S conversion circuit. In this way, the digital video signal corresponding to each source signal line is reflected in the writing of an appropriate source signal line. This state is shown in D0_1 to Dn_1 and D0_4 to Dn_4 in FIG. Here, Di_1 is the (i + 1) th bit output data of the left P / S conversion circuit in FIG. 3, and Di_4 is the (i + 1) th bit output data of the right P / S conversion circuit in FIG. It is.
[0053]
Next, it is shown that source line inversion and dot inversion driving can be performed by the method of inputting the gradation power supply line switching control signal SVr to the D / A conversion circuit.
[0054]
The input signal of the control signal SVr when performing source line inversion driving is indicated by SVr (s) and SVr (sb) in FIG. Here, SVr (sb) indicates the control signal SVr in the next frame period when SVr (s) is input, and is an inverted signal of SVr (s). As a result, the polarity written in each pixel is as shown in FIG.
[0055]
In addition, the method of inputting the control signal SVr when performing dot inversion driving is shown in SVr (d) and SVr (db) in FIG. Here, SVr (db) represents the control signal SVr in the next frame period when SVr (d) is input, and is an inverted signal of SVr (d). As a result, the polarity written to each pixel is as shown in FIG.
[0056]
As described above, according to this embodiment, even when three source signal lines are driven by one D / A conversion circuit, the source line inversion driving method and the dot inversion driving method can be performed. In this embodiment, the case where three source signal lines are driven by one D / A conversion circuit is described as an example, but the present invention is not limited to this, and three, five lines are used. ,... Can also be applied to driving an odd number of source signal lines with one D / A conversion circuit.
[0057]
[Embodiment 3]
In this embodiment, although the circuit configuration is the same as that of the first embodiment, a method of extending the period of the control signal for controlling the connection changeover switch of the gradation power supply line by changing the signal input method is shown.
[0058]
The operation timing for FIG. 1 at this time is shown in FIG. As in the first embodiment, one gate signal line selection period is divided into four, SS1 is set to Hi level and sw1 is turned on in the first period, SS3 is set to Hi level and sw3 is turned on in the second period. In the third period, SS2 is set to Hi level and sw2 is turned on, and in the fourth period, SS4 is set to Hi level and sw4 is turned on. The output of each bit data of each P / S conversion circuit is synchronized with the selection signal (SS1 to SS4), the gate signal line selection period is divided into four, and the (4k) in the first period. +1) The source signal line data is output, the (4k + 3) source signal line data is output in the second period, and the (4k + 2) source signal line is output in the third period. Is controlled by the selection signal SS input to the P / S conversion circuit so that the data of the (4k + 4) th source signal line is output in the fourth period. In this way, the digital video signal corresponding to each source signal line is reflected in the writing of an appropriate source signal line. This state is shown in D0_1 to Dn_1 and D0_5 to Dn_5 in FIG. Here, Di_1 is output data of the (i + 1) th bit of the left P / S conversion circuit in FIG. 1, and Di_5 is output data of the (i + 1) th bit of the right P / S conversion circuit in FIG. It is.
[0059]
The input signal of the control signal SVr when performing source line inversion driving is indicated by SVr (s) and SVr (sb) in FIG. Here, SVr (sb) indicates the control signal SVr in the next frame period when SVr (s) is input, and is an inverted signal of SVr (s). As a result, the polarity written in each pixel is as shown in FIG. It can be seen that SVr (s) and SVr (sb) in FIG. 5 have longer periods than those in FIG.
[0060]
Further, a method of inputting the control signal SVr when performing dot inversion driving is shown in SVr (d) and SVr (db) in FIG. Again, SVr (db) indicates the control signal SVr in the next frame period when SVr (d) is input, and is an inverted signal of SVr (d). As a result, the polarity written to each pixel is as shown in FIG. It can be seen that SVr (d) and SVr (db) in FIG. 5 have longer periods than those in FIG. It can also be seen that the cycle of SVr (d) and SVr (db) is the longest compared to SVr (s) and SVr (sb) in FIG.
[0061]
As described above, according to this embodiment, even when four source signal lines are driven by one D / A conversion circuit, the source line inversion driving method and the dot inversion driving method are performed, and the gradation power source line is selected. It is possible to lengthen the cycle of the control signal to be performed. In this embodiment, the case where four source signal lines are driven by one D / A conversion circuit is described as an example. However, the present invention is not limited to this, and is an even number of four or more. The present invention can also be applied to the case where one source signal line is driven by one D / A conversion circuit. In the case where two source signal lines are driven by one D / A conversion circuit, the present embodiment is equivalent to the first embodiment.
[0062]
[Embodiment 4]
In this embodiment, the circuit configuration is the same as that of the second embodiment, but by changing the signal input method, the period of the control signal for controlling the connection switch of the gradation power supply line is made equal or longer. Indicates.
[0063]
The operation timing for FIG. 3 at this time is shown in FIG. As in the second embodiment, one gate signal line selection period is divided into three, SS1 is set to Hi level and sw1 is turned on in the first period, SS3 is set to Hi level and sw3 is turned on in the second period. In the third period, SS2 is set to Hi level and sw2 is turned on. The output of each bit data of each P / S conversion circuit is synchronized with the selection signal (SS1 to SS3), the gate signal line selection period is divided into three, and the first (3k) +1) The source signal line data is output, the (3k + 3) source signal line data is output in the second period, and the (3k + 2) source signal line is output in the third period. Is controlled by the selection signal SS input to the P / S conversion circuit. In this way, the digital video signal corresponding to each source signal line is reflected in the writing of an appropriate source signal line. This state is shown in D0_1 to Dn_1 and D0_4 to Dn_4 in FIG. Here, Di_1 is the (i + 1) th bit output data of the left P / S conversion circuit in FIG. 3, and Di_4 is the (i + 1) th bit output data of the right P / S conversion circuit in FIG. It is.
[0064]
The input signal of the control signal SVr when performing source line inversion driving is indicated by SVr (s) and SVr (sb) in FIG. Here, SVr (sb) indicates the control signal SVr in the next frame period when SVr (s) is input, and is an inverted signal of SVr (s). As a result, the polarity written in each pixel is as shown in FIG. It can be seen that SVr (s) and SVr (sb) in FIG. 6 have the same period as those in FIG.
[0065]
Further, the method of inputting the control signal SVr when performing dot inversion driving is shown in SVr (d) and SVr (db) in FIG. Again, SVr (db) indicates the control signal SVr in the next frame period when SVr (d) is input, and is an inverted signal of SVr (d). As a result, the polarity written to each pixel is as shown in FIG. It can be seen that SVr (d) and SVr (db) in FIG. 6 have longer periods than those in FIG. It can also be seen that the cycle of SVr (d) and SVr (db) is the longest compared to SVr (s) and SVr (sb) in FIG.
[0066]
As described above, according to the present embodiment, even when three source signal lines are driven by one D / A conversion circuit, the source line inversion driving method and the dot inversion driving method are performed, and the gradation power source line is selected. It is possible to make the cycle of the control signal to be equal to or longer than that of the second embodiment. In this embodiment, the case where three source signal lines are driven by one D / A conversion circuit is described as an example. However, the present invention is not limited to this, and three or more odd numbers are used. The present invention can also be applied to the case where one source signal line is driven by one D / A conversion circuit. If five or more source signal lines are driven by a single D / A converter circuit, according to the present embodiment, the period of the control signal for selecting the gradation power supply line in the source line inversion drive is determined from the second embodiment. Can also be long.
[0067]
[Embodiment 5]
In the present embodiment, unlike the first embodiment, one grayscale power supply line is supplied to the D / A conversion circuit, and the polarity of the power supply voltage of the grayscale power supply line is reversed to drive the source line or the dot. One method that enables this is described.
[0068]
In this embodiment, a case where four source signal lines are driven by one D / A conversion circuit and corresponding to a digital video signal input of (n + 1) bits (n is an integer of 0 or more) will be described as an example.
[0069]
FIG. 7 shows a schematic circuit diagram of the present embodiment. In FIG. 7, the shift register unit, the latch 1 circuit unit, and the latch 2 circuit unit are omitted as in FIG. The parallel / serial conversion circuit (P / S conversion circuit) outputs parallel output data (D0 [4k + 1] to Dn [4k + 1], D0 [4k + 2] to Dn [4k + 2]) of the two latch circuits. , D0 [4k + 3] to Dn [4k + 3] and D0 [4k + 4] to Dn [4k + 4] (k is an integer equal to or greater than 0)) are converted into serial data.
[0070]
The source line selection circuit includes four switches sw1, sw2, sw3, and sw4. When sw1 is turned on, the (4k + 1) th source signal line is connected to the output of the D / A conversion circuit, and when sw2 is turned on, the first line is selected. The (4k + 2) th source signal line is connected to the output of the D / A conversion circuit. When sw3 is turned on, the (4k + 3) th source signal line is connected to the output of the D / A conversion circuit, and sw4 When is turned on, the (4k + 4) th source signal line is connected to the output of the D / A converter circuit. SS1 to SS4 are selection signals for controlling on / off of sw1 to sw4, respectively.
[0071]
The signal operation timing of FIG. 7 is shown in FIG. One gate signal line selection period is divided into four, SS1 is set to Hi level and sw1 is turned on in the first period, SS2 is set to Hi level and sw2 is turned on in the second period, and the third period Fig. 5 shows an operation of setting SS3 to Hi level and turning on sw3, and setting SS4 to Hi level and turning on sw4 in the fourth period. The output of each bit data of each P / S conversion circuit is synchronized with the above selection signals (SS1 to SS4), the gate signal line selection period is divided into four, and the first (4k) +1) The source signal line data is output, the (4k + 2) source signal line data is output during the second period, and the (4k + 3) source signal line is output during the third period. Is controlled by the selection signal input to the P / S conversion circuit so that the data of the (4k + 4) th source signal line is output in the fourth period. In this way, the digital video signal corresponding to each source signal line is reflected in the writing of an appropriate source signal line. This state is shown in D0_1 to Dn_1 and D0_5 to Dn_5 in FIG. Here, Di_1 is the (i + 1) th bit output data of the left P / S conversion circuit in FIG. 7, and Di_5 is the (i + 1) th bit output data of the right P / S conversion circuit in FIG. It is.
[0072]
Next, it is shown that source line inversion and dot inversion driving can be performed by the method of inputting the power supply voltage of the gradation power supply line Vref connected to the D / A conversion circuit.
[0073]
A method for inputting the power supply voltage of the gradation power supply line Vref when performing source line inversion driving is shown in Vref (s) and Vref (sb) of FIG. In the figure, (+) indicates that a positive polarity output voltage is supplied to the gradation power supply line, and (−) indicates that a negative polarity output voltage is supplied to the gradation power supply line. Vref (sb) indicates a method of inputting the power supply voltage of the gradation power supply line Vref in the next frame period when Vref (s) is input, and is in an inverted relationship with Vref (s). As a result, the polarity written in each pixel is as shown in FIG.
[0074]
In addition, a method for inputting the power supply voltage of the gradation power supply line Vref when performing dot inversion driving is shown in Vref (d) and Vref (db) in FIG. Here again, Vref (db) indicates the input method of the power supply voltage of the gradation power supply line Vref in the next frame period when Vref (d) is input, and is in an inverted relationship with Vref (d). As a result, the polarity written to each pixel is as shown in FIG.
[0075]
As described above, according to the present embodiment, when a plurality of source signal lines are driven by one D / A conversion circuit, the source line inversion driving method and the dot inversion driving method can be performed. In this embodiment, the case where four source signal lines are driven by one D / A conversion circuit is described as an example. However, the present invention is not limited to this, and two, four lines are used. The present invention can also be applied to a case where an even number of source signal lines such as... Are driven by one D / A conversion circuit.
[0076]
[Embodiment 6]
In this embodiment, the circuit configuration is the same as that of the fifth embodiment, but a method of extending the period of inversion of the polarity of the power supply voltage of the gradation power supply line by changing the input method of the power supply voltage of the gradation power supply line. Show.
[0077]
The operation timing for FIG. 7 at this time is shown in FIG. As in the fifth embodiment, one gate signal line selection period is divided into four, SS1 is set to Hi level and sw1 is turned on in the first period, and SS3 is set to Hi level and sw3 is turned on in the second period. In the third period, SS2 is set to Hi level and sw2 is turned on, and in the fourth period, SS4 is set to Hi level and sw4 is turned on. The output of each bit data of each P / S conversion circuit is synchronized with the above selection signals (SS1 to SS4), the gate signal line selection period is divided into four, and the first (4k) +1) The source signal line data is output, the (4k + 3) source signal line data is output in the second period, and the (4k + 2) source signal line is output in the third period. Is controlled by the selection signal input to the P / S conversion circuit so that the data of the (4k + 4) th source signal line is output in the fourth period. In this way, the digital video signal corresponding to each source signal line is reflected in the writing of an appropriate source signal line. This state is shown in D0_1 to Dn_1 and D0_5 to Dn_5 in FIG. Here, Di_1 is the (i + 1) th bit output data of the left P / S conversion circuit in FIG. 7, and Di_5 is the (i + 1) th bit output data of the right P / S conversion circuit in FIG. It is.
[0078]
Next, source line inversion and dot inversion driving can be performed by a method of inputting the power supply voltage of the gradation power supply line Vref to the D / A conversion circuit, and the period of the inversion of the polarity of the power supply voltage is longer than that of the fifth embodiment. Show what you can do.
[0079]
The method of inputting the power supply voltage of the gradation power supply line Vref when performing source line inversion driving is shown in Vref (s) and Vref (sb) of FIG. In the figure, (+) indicates that a positive polarity output voltage is supplied to the gradation power supply line, and (−) indicates that a negative polarity output voltage is supplied to the gradation power supply line. Vref (sb) indicates a method of inputting the power supply voltage of the gradation power supply line Vref in the next frame period when Vref (s) is input, and is in an inverted relationship with Vref (s). As a result, the polarity written in each pixel is as shown in FIG. It can be seen that Vref (s) and Vref (sb) in FIG. 9 have longer periods for inverting the polarity than those in FIG.
[0080]
Further, the method of inputting the power supply voltage of the gradation power supply line Vref when performing dot inversion driving is shown in Vref (d) and Vref (db) of FIG. Here again, Vref (db) indicates the input method of the power supply voltage of the gradation power supply line Vref in the next frame period when Vref (d) is input, and is in an inverted relationship with Vref (d). As a result, the polarity written to each pixel is as shown in FIG. It can be seen that Vref (d) and Vref (db) in FIG. 9 have a longer period of inversion of the polarity of the power supply voltage than those in FIG. It can also be seen that the periods of Vref (d) and Vref (db) are the longest compared to Vref (s) and Vref (sb) in FIG.
[0081]
As described above, according to this embodiment, when a plurality of source signal lines are driven by one D / A conversion circuit, the source line inversion driving method and the dot inversion driving method are performed, and the polarity of the power supply voltage of the gradation power source line is It is possible to lengthen the inversion period. In this embodiment, the case where four source signal lines are driven by one D / A conversion circuit is described as an example. However, the present invention is not limited to this, and is an even number of four or more. The present invention can also be applied to the case where one source signal line is driven by one D / A conversion circuit. In the case where two source signal lines are driven by one D / A conversion circuit, the present embodiment is equivalent to the fifth embodiment.
[0082]
[Embodiment 7]
In this embodiment, as in the first embodiment, two independent grayscale power supply lines are supplied to the source signal line drive circuit in order to obtain outputs with different polarities from the D / A conversion circuit. The source signal line driven by the conversion circuit is discriminated whether it is odd-numbered or even-numbered, and each D / A conversion circuit that drives the odd-numbered source signal line is connected with a first system gradation power supply line. Each D / A conversion circuit for driving the second source signal line is connected to the second-level gradation power supply line, and by further changing the polarity of the gradation power supply line, it is possible to perform source line inversion and dot inversion driving. One method will be described.
[0083]
In this embodiment, a case where two source signal lines are driven by one D / A conversion circuit and corresponding to a digital video signal input of (n + 1) bits (n is an integer of 0 or more) will be described as an example.
[0084]
FIG. 10 shows a schematic circuit diagram of the present embodiment. In FIG. 10, the shift register unit, the latch 1 circuit unit, and the latch 2 circuit unit are omitted as in FIG. The parallel / serial conversion circuit (P / S conversion circuit) outputs parallel output data (D0 [4k + 1] to Dn [4k + 1], D0 [4k + 3] to Dn [4k + 3]) of the two latch circuits. Alternatively, D0 [4k + 2] to Dn [4k + 2] and D0 [4k + 4] to Dn [4k + 4] (k is an integer equal to or greater than 0) are collectively converted into serial data.
[0085]
Here, the digital video signal input to each parallel / serial conversion circuit is either an odd-numbered source signal line or an even-numbered source signal line. Reflecting this, the digital video signal input to each D / A conversion circuit is either an odd-numbered source signal line or an even-numbered source signal line.
[0086]
Each D / A converter circuit to which the digital video signal of the odd-numbered source signal line is input is connected to the first system gradation power supply line Vref1, and the digital video signal of the even-numbered source signal line is input. Each D / A conversion circuit is connected with a second-system gradation power supply line Vref2.
[0087]
The source line selection circuit is composed of two switches sw1 and sw2. When sw1 is turned on, the (4k + 1) th and (4k + 2) th source signal lines are connected to the outputs of the respective D / A conversion circuits. When sw2 is turned on, the (4k + 3) th and (4k + 4) th source signal lines are connected to the output of each D / A conversion circuit. SS1 to SS2 are selection signals for controlling on / off of sw1 and sw2, respectively.
[0088]
The signal operation timing of FIG. 10 is shown in FIG. One gate signal line selection period is divided into two, and SS1 is set to Hi level and sw1 is turned on in the first period, and SS2 is set to Hi level and sw2 is turned on in the second period. The output of each bit data of each P / S conversion circuit is synchronized with the selection signal (SS1 to SS2), the gate signal line selection period is divided into two, and the first (4k) +1) The data of the source signal line or the (4k + 2) source signal line is output, and the data of the (4k + 3) source signal line or the (4k + 4) source signal line is output in the second period. Is controlled by a selection signal input to the P / S conversion circuit. In this way, the digital video signal corresponding to each source signal line is reflected in the writing of an appropriate source signal line. This state is shown in D0_1 to Dn_1 and D0_2 to Dn_2 in FIG. Here, Di_1 is the (i + 1) th bit output data of the left P / S conversion circuit in FIG. 10, and Di_2 is the (i + 1) th bit output data of the right P / S conversion circuit in FIG. It is.
[0089]
When the source line inversion drive is performed, the power supply voltage input method for the first system gradation power supply line Vref1 and the second system gradation power supply line Vref2 is shown as Vref1 (s), Vref2 (s) and Vref1 ( sb) and Vref2 (sb). In the figure, (+) indicates that a positive polarity output voltage is supplied to the corresponding gradation power supply line, and (−) indicates that a negative polarity output voltage is supplied to the corresponding gradation power supply line. Vref1 (sb) indicates a method for inputting the power supply voltage of the first system gradation power supply line Vref1 in the next frame period when Vref1 (s) is input, and is in an inverted relationship with Vref1 (s). Similarly, Vref2 (sb) indicates a method for inputting the power supply voltage of the second-level grayscale power supply line Vref2 in the next frame period when Vref2 (s) is input, and is in an inverted relationship with Vref2 (s). As a result, the polarity written in each pixel is as shown in FIG.
[0090]
In addition, when performing dot inversion driving, the power supply voltage input method of the first system gradation power supply line Vref1 and the second system gradation power supply line Vref2 is shown as Vref1 (d), Vref2 (d) and Vref1 in FIG. (Db) and Vref2 (db). Vref1 (db) indicates a method of inputting the power supply voltage of the first system gradation power supply line Vref1 in the next frame period when Vref1 (d) is input, and is in an inverted relationship with Vref1 (d). Similarly, Vref2 (db) indicates a method for inputting the power supply voltage of the second-level grayscale power supply line Vref2 in the next frame period when Vref2 (d) is input, and is in an inverted relationship with Vref2 (d). As a result, the polarity written to each pixel is as shown in FIG.
[0091]
As described above, according to the present embodiment, when two source signal lines are driven by one D / A conversion circuit, the source line inversion driving method and the dot inversion driving method can be performed. In this embodiment, the case where two source signal lines are driven by one D / A conversion circuit is described as an example. However, the present invention is not limited to this, and an arbitrary number of sources can be used. The present invention can also be applied to a case where the signal line is driven by one D / A conversion circuit.
[0092]
As described above, in all the embodiments, the parallel / serial conversion circuit (P / S conversion circuit) is used, but the present invention is not limited to this. That is, the present invention can be applied to any method in which digital video signals of a plurality of source signal lines are serially input to a D / A conversion circuit for one horizontal writing period.
[0093]
【Example】
Now, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.
[0094]
[Example 1]
In this example, an active matrix liquid crystal display device will be described as an example of the first embodiment.
[0095]
As shown in FIG. 40, the active matrix liquid crystal display device includes a source signal line drive circuit 101, a gate signal line drive circuit 102, and a pixel array unit 103 arranged in a matrix.
[0096]
FIG. 13 shows a circuit configuration example of the source signal line driver circuit corresponding to the first embodiment. For convenience of explanation, a case will be described in which an input digital video signal has 3 bits and four source signal lines are driven by one D / A conversion circuit.
[0097]
Please refer to FIG. The shift register unit includes a flip-flop circuit FF, a NAND circuit, and an inverter, and receives a clock signal CLK, an inverted clock signal CLKb of the clock signal CLK, and a start pulse SP. As shown in FIG. 14A, the flip-flop circuit FF includes a clocked inverter and an inverter.
[0098]
When the start pulse SP is input, the sampling pulse is sequentially shifted in synchronization with the clock signals CLK and CLKb.
[0099]
The latch 1 part and the latch 2 part, which are storage circuits, are composed of a basic latch circuit LAT. A basic latch circuit is shown in FIG. The basic latch circuit LAT includes a clocked inverter and an inverter. A 3-bit digital video signal (D0, D1, D2) is input to the latch 1 unit, and the digital video signal is latched by a sampling pulse from the shift register unit. The latch 2 unit simultaneously latches the digital video signals held in the latch 1 unit by a latch pulse LP input during the horizontal blanking period and simultaneously transmits information to a downstream circuit. At this time, the latch 2 portion holds data for one horizontal writing period.
[0100]
14A and 14B, the connection of the P channel type clock input terminal of each clocked inverter is omitted, but the inverted signal of the clock signal actually input to the N channel type clock input terminal is omitted. Is entered. In the present embodiment, the flip-flop circuit FF and the basic latch circuit LAT have the same circuit configuration, but may have different circuit configurations.
[0101]
To the parallel / serial conversion circuit (referred to as P / S conversion circuit A in FIG. 13), the digital video signal stored in the latch 2 part of 3 bit data × 4 (four source signal lines) and selection Signals SS1 to SS4 are input from the outside. As shown in FIG. 15A, the P / S conversion circuit A is composed of a NAND circuit.
[0102]
FIG. 17 shows signal operation timings paying attention to the P / S conversion circuit A related to the first to fourth source signal lines (SL1 to SL4). One gate signal line selection period is divided into four, SS1 is set to Hi level in the first period, and the digital video signal of the first source signal line SL1 is output to the D / A conversion circuit. In the second period, SS2 is set to Hi level, and the digital video signal of the second source signal line SL2 is output to the D / A conversion circuit. In the third period, SS3 is set to the Hi level, and the digital video signal of the third source signal line SL3 is output to the D / A conversion circuit. In the final fourth period, SS4 is set to Hi level, and the digital video signal of the fourth source signal line SL4 is output to the D / A conversion circuit. This state is shown by D0_1, D1_1, and D2_1 in FIG. Here, Di_1 is the (i + 1) th bit output data of the P / S conversion circuit A related to the first to fourth source signal lines (SL1 to SL4) of interest. As described above, Di [s, g] represents the (i + 1) th bit data for the pixel in the sth column and the gth row.
[0103]
A similar operation is performed in parallel in the P / S conversion circuit A related to other source signal lines (SL5 to SL8, SL9 to SL12,...).
[0104]
FIG. 16 shows a circuit configuration example of the D / A conversion circuit. FIG. 16 shows a resistor string type D / A conversion circuit, and it is necessary to supply two gradation power supply lines in order to obtain an output in a certain voltage range. In FIG. 16, these are indicated as Vref_L and Vref_H. These gradation power supply voltages are divided by resistors, and a voltage value corresponding to a 3-bit input digital video signal is output.
[0105]
According to the first embodiment, two independent gradation power supply lines are supplied to the source signal line driver circuit, so that four gradation power supply lines are required in total. In FIG. 13, these are indicated as Vref1_L and Vref1_H for the first system, and Vref2_L and Vref2_H for the second system.
[0106]
FIG. 14C shows a circuit configuration example of the connection changeover switch SW for switching the connection between the two systems of gradation power supply lines and the D / A conversion circuit. In the connection example of FIG. 13, when the control signal SVr is Hi, the first system gradation power supply lines Vref1_L and Vref1_H are connected to the D / A conversion circuit, and when SVr is Lo, the second system gradation is applied. The power supply lines Vref2_L and Vref2_H are connected to the D / A conversion circuit.
[0107]
The output of the D / A conversion circuit is connected to an appropriate source signal line via the source line selection circuit A. A circuit configuration example of the source line selection circuit A is shown in FIG. The source line selection circuit A includes four transfer gates (switches), and selection signals SS1 to SS4 and their inverted signals are input to the gates. According to the signal operation timing of FIG. 17, the one-gate signal line selection period is divided into four. In the first period, the switch sw1 is turned on and the output of the D / A converter circuit is supplied to the first source signal line SL1. Write. In the second period, the switch sw2 is turned on and the output of the D / A conversion circuit is written to the second source signal line SL2. In the next, third period, the switch sw3 is turned on and the output of the D / A conversion circuit is written to the third source signal line SL3. In the last fourth period, the switch sw4 is turned on to write the output of the D / A conversion circuit to the fourth source signal line SL4.
[0108]
Such writing is performed in parallel to other source signal lines. The data written to each source signal line is sequentially written to each pixel by the action of the gate signal line driving circuit and the pixel TFT.
[0109]
An example of input of the control signal SVr when performing source line inversion driving is shown in SVr (s) and SVr (sb) in FIG. Here, SVr (sb) indicates the control signal SVr in the next frame period when SVr (s) is input, and is also an inverted signal of SVr (s).
[0110]
During a certain frame period, one gate signal line selection period is divided into four. In the first and third periods, the control signal SVr is set to Hi and the first system gradation power supply line and the D / A conversion circuit In the second and fourth periods, the control signal SVr is set to Lo to connect the second-level gradation power supply line and the D / A conversion circuit. (SVr (s) in FIG. 17)
[0111]
During the next frame period, one gate signal line selection period is divided into four. In the first and third periods, the control signal SVr is set to Lo and the second-level gradation power supply line and D / A conversion are performed. The circuit is connected, and in the second and fourth periods, the control signal SVr is set to Hi to connect the first system gradation power supply line and the D / A conversion circuit. (SVr (sb) in FIG. 17)
[0112]
In this embodiment, the voltage values of the first system gradation power supply lines Vref1_L and Vref1_H are + 1V and + 5V, respectively, and the voltage values of the second system gradation power supply lines Vref2_L and Vref2_H are −1V and −5V, respectively. This means that if the D / A conversion circuit is connected to the first system gradation power supply line, it outputs a positive polarity, and if it is connected to the second system gradation power supply line, it outputs a negative polarity. .
[0113]
By the above method, the source line inversion driving shown in FIG.
[0114]
In addition, an example of input of the control signal SVr when performing dot inversion driving is shown in SVr (d) and SVr (db) in FIG. Here, SVr (db) indicates a control signal SVr in the next frame period when SVr (d) is input, and is also an inverted signal of SVr (d). Further, the control signal SVr in a certain gate signal line selection period is an inversion of the control signal in the previous gate signal line selection period.
[0115]
In this way, the dot inversion driving shown in FIG. 12B is possible.
[0116]
In this embodiment, the selection signals SS1 to SS4 input to the P / S conversion circuit A and the source line selection circuit A are the same, but they may be different systems.
[0117]
In this embodiment, the circuit driving power supply supplied to the source signal line driving circuit is assumed to be one system, but two or more systems may be used, and a level shifter circuit may be inserted in a necessary portion.
[0118]
[Example 2]
In this example, an active matrix liquid crystal display device will be described as an example of the second embodiment. The following description focuses on the source signal line driving circuit as in the first embodiment.
[0119]
FIG. 18 shows a circuit configuration example of a source signal line driver circuit corresponding to the second embodiment. For convenience of explanation, a case will be described in which an input digital video signal has 3 bits and three source signal lines are driven by one D / A conversion circuit.
[0120]
Please refer to FIG. The shift register unit, the latch unit 1 and the latch unit 2 are the same as those in the first embodiment.
[0121]
To the parallel / serial conversion circuit (referred to as P / S conversion circuit B in FIG. 18), the digital video signal stored in the latch 2 part of 3 bit data × 3 (three source signal lines) and selection Signals SS1 to SS3 are input from the outside. As shown in FIG. 23A, the P / S conversion circuit B is composed of a NAND circuit.
[0122]
FIG. 19 shows signal operation timings paying attention to the P / S conversion circuit B related to the first to third source signal lines (SL1 to SL3). One gate signal line selection period is divided into three, SS1 is set to Hi level in the first period, and the digital video signal of the first source signal line SL1 is output to the D / A conversion circuit. In the second period, SS2 is set to Hi level, and the digital video signal of the second source signal line SL2 is output to the D / A conversion circuit. In the final third period, SS3 is set to Hi level, and the digital video signal of the third source signal line SL3 is output to the D / A conversion circuit. This state is shown in D0_1, D1_1, and D2_1 in FIG. Here, Di_1 is the (i + 1) th bit output data of the P / S conversion circuit B related to the first to third source signal lines (SL1 to SL3) of interest. As described above, Di [s, g] represents the (i + 1) th bit data for the pixel in the sth column and the gth row.
[0123]
A similar operation is also performed in parallel in the P / S conversion circuit B related to the other source signal lines (SL4 to SL6, SL7 to SL9,...).
[0124]
The D / A conversion circuit is assumed to be shown in FIG.
[0125]
Also in the second embodiment, since two independent gradation power supply lines are supplied to the source signal line driving circuit, a total of four gradation power supply lines are required. Also in FIG. 18, these are indicated as Vref1_L and Vref1_H for the first system, and Vref2_L and Vref2_H for the second system.
[0126]
The circuit configuration of the connection changeover switch SW for switching the connection between the above-described two systems of gradation power supply lines and the D / A conversion circuit is the same as that of the first embodiment, and is shown in FIG. However, the connection method with the gradation power supply line is different. In other words, adjacent connection changeover switches SW are alternately connected to the first system and the second system gradation power supply line. In the connection example of FIG. 18, the connection changeover switch SW related to the first to third source signal lines (SL1 to SL3) uses the first system power supply lines Vref1_L and Vref1_H when the control signal SVr is Hi. When the control signal SVr is Lo, the second gradation power supply lines Vref2_L and Vref2_H are connected to the D / A conversion circuit. On the other hand, the connection changeover switch SW related to the adjacent fourth to sixth source signal lines (SL4 to SL6) converts the second-system gradation power supply lines Vref2_L and Vref2_H to the D / A conversion circuit when the control signal SVr is Hi. When the control signal SVr is Lo, the first-system gradation power supply lines Vref1_L and Vref1_H are connected to the D / A conversion circuit.
[0127]
The output of the D / A conversion circuit is connected to an appropriate source signal line via the source line selection circuit B. A circuit configuration example of the source line selection circuit B is shown in FIG. The source line selection circuit B includes three transfer gates (switches), and selection signals SS1 to SS3 and their inverted signals are input to each gate. According to the signal operation timing of FIG. 19, the one-gate signal line selection period is divided into three. In the first period, the switch sw1 is turned on and the output of the D / A converter circuit is supplied to the first source signal line SL1. Write. In the second period, the switch sw2 is turned on and the output of the D / A conversion circuit is written to the second source signal line SL2. In the last, third period, the switch sw3 is turned on and the output of the D / A conversion circuit is written to the third source signal line SL3.
[0128]
Such writing is performed in parallel to other source signal lines. The data written to each source signal line is sequentially written to each pixel by the action of the gate signal line driving circuit and the pixel TFT.
[0129]
An example of input of the control signal SVr when performing source line inversion driving is shown in SVr (s) and SVr (sb) of FIG. Here, SVr (sb) indicates the control signal SVr in the next frame period when SVr (s) is input, and is also an inverted signal of SVr (s).
[0130]
During a certain frame period, the one gate signal line selection period is divided into three. In the first and third periods, the control signal SVr is set to Hi, the first to third source signal lines (SL1 to SL3), The connection changeover switch SW related to the seventh to ninth source signal lines (SL7 to SL9)... Connects the first system gradation power line and the corresponding D / A conversion circuit, and includes the fourth to sixth. The connection changeover switch SW related to the source signal lines (SL4 to SL6), the tenth to twelfth source signal lines (SL10 to SL12),..., The second system gradation power supply line, the corresponding D / A conversion circuit, and Connect. Conversely, the one gate signal line selection period is divided into three. In the second period, the control signal SVr is set to Lo, the first to third source signal lines (SL1 to SL3), and the seventh to ninth source signals. The connection changeover switch SW related to the lines (SL7 to SL9)... Connects the second gradation power supply line and the corresponding D / A conversion circuit, and the fourth to sixth source signal lines (SL4 to SL6). ), The connection changeover switch SW related to the tenth to twelfth source signal lines (SL10 to SL12)... (SVr (s) in FIG. 19)
[0131]
During the next frame period, the one gate signal line selection period is divided into three. In the first and third periods, the control signal SVr is set to Lo, and the first to third source signal lines (SL1 to SL3). ), The connection changeover switch SW related to the seventh to ninth source signal lines (SL7 to SL9)... Connects the second-system gradation power supply line and the corresponding D / A conversion circuit, and The connection changeover switch SW related to the sixth source signal lines (SL4 to SL6), the tenth to twelfth source signal lines (SL10 to SL12),... Connect the circuit. Conversely, the one gate signal line selection period is divided into three. In the second period, the control signal SVr is set to Hi, the first to third source signal lines (SL1 to SL3), and the seventh to ninth source signals. The connection changeover switch SW related to the lines (SL7 to SL9)... Connects the first system gradation power supply line and the corresponding D / A conversion circuit, and the fourth to sixth source signal lines (SL4 to SL6). ), The connection changeover switch SW related to the tenth to twelfth source signal lines (SL10 to SL12),... (SVr (sb) in FIG. 19)
[0132]
In the present embodiment, as in the first embodiment, the voltage values of the first system gradation power supply lines Vref1_L and Vref1_H are + 1V and + 5V, respectively, and the voltage values of the second system gradation power supply lines Vref2_L and Vref2_H are −1V, respectively. -5V. As a result, if the D / A conversion circuit is connected to the first system gradation power supply line, it outputs a positive polarity, and if it is connected to the second system gradation power supply line, it outputs a negative polarity.
[0133]
By the above method, the source line inversion driving shown in FIG.
[0134]
Further, an example of input of the control signal SVr when performing dot inversion driving is shown in SVr (d) and SVr (db) of FIG. Here, SVr (db) indicates a control signal SVr in the next frame period when SVr (d) is input, and is also an inverted signal of SVr (d). A control signal in a certain gate signal line selection period is an inverted version of the control signal in the immediately preceding gate signal line selection period.
[0135]
By doing so, the dot inversion driving shown in FIG. 12B can be performed.
[0136]
In this embodiment, the selection signals SS1 to SS3 input to the P / S conversion circuit B and the source line selection circuit B are the same, but they may be different systems.
[0137]
In this embodiment, the circuit driving power supply supplied to the source signal line driving circuit is assumed to be one system, but two or more systems may be used, and a level shifter circuit may be inserted in a necessary portion.
[0138]
[Example 3]
In this example, an active matrix liquid crystal display device will be briefly described as a specific example of the third embodiment.
[0139]
The circuit configuration example of the source signal line driver circuit corresponding to the third embodiment is the same as that of the first embodiment and is shown in FIG. The difference from the first embodiment is the input method of the selection signals SS1 to SS4 and the control signal SVr. The selection signals SS1 to SS4 as shown in FIG. 5 are input, and the control signal SVr is SVr (s), SVr (sb) when performing source line inversion driving, and SVr (d) when performing dot inversion driving. , SVr (db).
[0140]
[Example 4]
In this example, an active matrix liquid crystal display device will be briefly described as a specific example of the fourth embodiment.
[0141]
A circuit configuration example of the source signal line driver circuit corresponding to the fourth embodiment is the same as that of the second embodiment and is shown in FIG. The difference from the second embodiment is the input method of the selection signals SS1 to SS3 and the control signal SVr. The selection signals SS1 to SS3 as shown in FIG. 6 are input, and the control signal SVr is SVr (s), SVr (sb) when performing source line inversion driving, and SVr (d) when performing dot inversion driving. , SVr (db).
[0142]
[Example 5]
In this example, an active matrix liquid crystal display device will be described as an example of the sixth embodiment. In the following description, the source signal line driving circuit will be described in the same manner as in the first to fourth embodiments.
[0143]
An example of the circuit configuration of the source signal line driver circuit corresponding to Embodiment 6 is shown in FIG. For convenience of explanation, a case will be described in which an input digital video signal has 3 bits and four source signal lines are driven by one D / A conversion circuit.
[0144]
Refer to FIG. The shift register unit, the latch unit 1 and the latch unit 2 are the same as those in the first to fourth embodiments.
[0145]
To the parallel / serial conversion circuit A (P / S conversion circuit A), the digital video signal stored in the latch 2 part of 3 bit data × 4 (four source signal lines) and the selection signals SS1 to SS4 Is input from the outside. As shown in FIG. 15A, the P / S conversion circuit is composed of a NAND circuit. This is the same circuit as that used in the first embodiment.
[0146]
FIG. 21 shows signal operation timing by paying attention to a portion for driving the first to fourth source signal lines (SL1 to SL4). One gate signal line selection period is divided into four, SS1 is set to Hi level in the first period, and the digital video signal of the first source signal line SL1 is output to the D / A conversion circuit. In the second period, SS3 is set to Hi level, and the digital video signal of the third source signal line SL3 is output to the D / A conversion circuit. In the third period, SS2 is set to Hi level, and the digital video signal of the second source signal line SL2 is output to the D / A conversion circuit. In the last fourth period, SS4 is set to Hi level, and the digital video signal of the fourth source signal line SL4 is output to the D / A conversion circuit. This state is shown in D0_1, D1_1, and D2_1 in FIG. Here, Di_1 is the (i + 1) th bit output data of the P / S conversion circuit A related to the first to fourth source signal lines (SL1 to SL4) of interest. As described above, Di [s, g] represents the (i + 1) th bit data for the pixel in the sth column and the gth row.
[0147]
A similar operation is performed in parallel in the P / S conversion circuit A related to other source signal lines (SL5 to SL8, SL9 to SL12,...).
[0148]
The D / A conversion circuit is the same as that of the first to fourth embodiments shown in FIG. To the D / A conversion circuit, two lines of gradation power supply lines Vref_L and Vref_H of one system and a 3-bit digital video signal are input from the P / S conversion circuit A.
[0149]
The output of the D / A conversion circuit is connected to an appropriate source signal line via the source line selection circuit A. A circuit configuration example of the source line selection circuit A is shown in FIG. This is also the same circuit as that used in the first embodiment. The source line selection circuit A includes four transfer gates (switches), and selection signals SS1 to SS4 and their inverted signals are input to the gates. In accordance with the signal operation timing of FIG. 21, the one gate signal line selection period is divided into four. In the first period, the switch sw1 is turned on and the output of the D / A converter circuit is supplied to the first source signal line SL1. Write. In the second period, the switch sw3 is turned on and the output of the D / A conversion circuit is written to the third source signal line SL3. In the next, third period, the switch sw2 is turned on to write the output of the D / A conversion circuit to the second source signal line SL2. In the last fourth period, the switch sw4 is turned on to write the output of the D / A conversion circuit to the fourth source signal line SL4.
[0150]
Such writing is performed in parallel to other source signal lines. The data written to each source signal line is sequentially written to each pixel by the action of the gate signal line driving circuit and the pixel TFT.
[0151]
FIGS. 21A and 21B show examples of input of two power supply voltages for the gradation power supply lines Vref_L and Vref_H in the case of performing source line inversion driving. Here, FIG. 21B shows power supply voltages of the grayscale power supply lines Vref_L and Vref_H in the next frame period when the grayscale power supply line is input as shown in FIG. 21A, and is in an inverted relationship with FIG. It is in.
[0152]
In this embodiment, Vref_L takes −1 and + 1V, and Vref_H takes −5 and + 5V as the voltage value of the gradation power supply line. When the combination of voltage values of the gradation power supply lines is {Vref_L = −1V, Vref_H = −5V}, the output of the D / A converter circuit has a negative polarity of −1V to −5V, and {Vref_L = + 1V, Vref_H = + 5V}, the output of the D / A converter circuit has a positive polarity of + 1V to + 5V. Unlike the first to fourth embodiments, the polarity of the power supply voltage of the gradation power supply line is inverted within one horizontal writing period.
[0153]
By the above method, the source line inversion driving shown in FIG.
[0154]
FIGS. 21C and 21D also show examples of input of two power supply voltages for the gradation power supply line Vref_L and Vref_H when performing dot inversion driving. FIG. 21D shows power supply voltages of the grayscale power supply lines Vref_L and Vref_H in the next frame period when the grayscale power supply line is input as shown in FIG. 21C, and is in an inverted relationship with FIG. .
[0155]
By doing so, the dot inversion driving shown in FIG. 12B can be performed.
[0156]
In this embodiment, the selection signals SS1 to SS4 input to the P / S conversion circuit A and the source line selection circuit A are the same, but they may be different systems.
[0157]
In this embodiment, the circuit driving power supply supplied to the source signal line driving circuit is assumed to be one system, but two or more systems may be used, and a level shifter circuit may be inserted in a necessary portion.
[0158]
[Example 6]
In this example, an active matrix liquid crystal display device will be briefly described as a specific example of the fifth embodiment.
[0159]
A circuit configuration example of the source signal line driving circuit corresponding to the fifth embodiment is the same as that of the fifth embodiment and is shown in FIG. The difference from the fifth embodiment is the method of inputting the selection signals SS1 to SS4 and the power supply voltages of the gradation power supply lines Vref_L and Vref_H. When the selection signals SS1 to SS4 as shown in FIG. 8 are input and the gradation power supply lines Vref_L and Vref_H are to perform source line inversion driving, Vref (s), Vref (sb), and dot inversion driving are to be performed. What is necessary is just to input so that it may become the polarity shown by Vref (d) and Vref (db).
[0160]
In this case, the cycle of inverting the polarity of the power supply voltage of the gradation power supply line is shorter than that shown in the fifth embodiment.
[0161]
[Example 7]
In this example, an active matrix liquid crystal display device will be described as an example of the seventh embodiment. In the following description, the source signal line driving circuit will be described in the same manner as in the first to sixth embodiments.
[0162]
FIG. 22 shows a circuit configuration example of a source signal line driver circuit corresponding to the seventh embodiment. For convenience of explanation, a case will be described in which the input digital video signal is 3 bits and two source signal lines are driven by one D / A conversion circuit.
[0163]
Refer to FIG. The shift register unit, the latch unit 1 and the latch unit 2 are the same as those in the first to sixth embodiments.
[0164]
To the parallel / serial conversion circuit (referred to as P / S conversion circuit C in FIG. 22), the digital video signal stored in the latch 2 section of 3 bits data × 2 (two source signal lines) and selection Signals SS1 and SS2 are input from the outside. Here, the digital video signal input from the latch 2 section is data related to the second and third source signal lines, data related to the sixth and seventh source signal lines, and generally related to the (4k + 2) th and (4k + 3) source signal lines. Data (k is an integer of 0 or more) is exchanged and input to the P / S conversion circuit C. As a result, each P / S conversion circuit C outputs only data information relating to odd-numbered source signal lines or even-numbered source signal lines to each D / A conversion circuit. Reflecting this, each D / A conversion circuit drives either the odd-numbered or even-numbered source signal line. Therefore, as shown in FIG. 22, among the outputs of the source line selection circuit, the data that has been replaced when input to the above-described P / S conversion circuit C is replaced again, and the data is transferred to an appropriate source signal line. Make it writable.
[0165]
The P / S conversion circuit C is composed of a NAND circuit as shown in FIG.
[0166]
FIG. 24 shows signal operation timing by paying attention to a portion for driving the first to fourth source signal lines (SL1 to SL4). As shown in FIG. 22, there are two P / S conversion circuits C, two D / A conversion circuits, and two source line selection circuits C in the portion for driving these four source signal lines. In order to distinguish these, hereinafter, one is referred to as a left P / S conversion circuit C, the other as a right P / S conversion circuit C, and the like. Speaking of... On the left side is a corresponding circuit located on the leftmost side in FIG.
[0167]
In the first period in which one gate signal line selection period is divided into two, SS1 is set to Hi level, and the left P / S conversion circuit C converts the digital video signal of the first source signal line SL1 to the left D / A output to the conversion circuit. At this time, the right P / S conversion circuit C outputs the digital video signal of the second source signal line SL2 to the right D / A conversion circuit. In the second period, SS2 is set to Hi level, and the left P / S conversion circuit C outputs the digital video signal of the third source signal line SL3 to the left D / A conversion circuit. At this time, the right P / S conversion circuit C outputs the digital video signal of the fourth source signal line SL4 to the right D / A conversion circuit. The outputs of the left P / S conversion circuit C are shown as D0_1, D1_1, and D2_1 in FIG. 24, and the outputs of the right P / S conversion circuit C are shown as D0_2, D1_2, and D2_2 in FIG. As described above, Di [s, g] indicates the (i + 1) th bit data for the pixel in the sth column and the gth row.
[0168]
A similar operation is performed in parallel in the P / S conversion circuit C related to the other source signal lines (SL5 to SL8, SL9 to SL12,...).
[0169]
The D / A conversion circuit is the same as that of the first to sixth embodiments shown in FIG. As shown in FIG. 22, the D / A conversion circuit for driving the odd-numbered source signal lines is connected to Vref1_L and Vref1_H, which are the first system gradation power supply lines, and drives the even-numbered source signal lines. The / A conversion circuit is connected to Vref2_L and Vref2_H, which are second-level gradation power supply lines.
[0170]
The output of the D / A conversion circuit is connected to an appropriate source signal line via the source line selection circuit C. A circuit configuration example of the source line selection circuit C is shown in FIG. The source line selection circuit C includes two transfer gates (switches), and selection signals SS1 and SS2 and their inverted signals are input to each gate. According to the signal operation timing in FIG. 24, the one-gate signal line selection period is divided into two, the switch sw1 is turned on in the first period, and the left source line selection circuit C is connected to the first source signal line SL1. Write the output of the left D / A converter circuit. At this time, the right source line selection circuit C writes the output of the right D / A conversion circuit to the second source signal line SL2. In the second period in which one gate signal line selection period is divided into two, the switch sw2 is turned on, and the left source line selection circuit C outputs to the third source signal line SL3 the output of the left D / A conversion circuit. Write. At this time, the right source line selection circuit C writes the output of the right D / A conversion circuit to the fourth source signal line SL4. Such writing is performed in parallel to other source signal lines.
[0171]
FIGS. 24A and 24B show examples of input of four power supply voltages of the gradation power supply lines Vref1_L, Vref1_H, Vref2_L, and Vref2_H when performing source line inversion driving. Here, FIG. 24B shows power supply voltages of the grayscale power supply lines Vref1_L, Vref1_H, Vref2_L, and Vref2_H in the next frame period when the grayscale power supply line is input as shown in FIG. Is in an inverted relationship.
[0172]
In this embodiment, Vref1_L and Vref2_L are −1 and + 1V, and Vref1_H and Vref2_H are −5 and + 5V as voltage values of the gradation power supply lines. When the combination of the voltage values of the gradation power supply lines is {Vrefx_L = −1V, Vrefx_H = −5V (x = 1 or 2)}, the output of the D / A converter circuit has a negative polarity of −1V to −5V. , {Vrefx_L = + 1V, Vrefx_H = + 5V (x = 1 or 2)}, the output of the D / A converter circuit has a positive polarity of + 1V to + 5V. Unlike the first to sixth embodiments, in the case of source line inversion, the polarity of the power supply voltage of the gradation power supply line is constant during one frame period.
[0173]
By the above method, the source line inversion driving shown in FIG.
[0174]
FIGS. 24C and 24D show examples of input of four power supply voltages of the gradation power supply lines Vref1_L, Vref1_H, Vref2_L, and Vref2_H in the case of performing dot inversion driving. FIG. 24D shows power supply voltages of the grayscale power supply lines Vref1_L, Vref1_H, Vref2_L, and Vref2_H in the next frame period when the grayscale power supply line is input as shown in FIG. Inversion relationship. The polarity of the power supply voltage of the gradation power supply line is inverted every one gate signal line selection period.
[0175]
By doing so, the dot inversion driving shown in FIG. 12B can be performed.
[0176]
In this embodiment, the selection signals SS1 and SS2 input to the P / S conversion circuit C and the source line selection circuit C are the same, but they may be different systems.
[0177]
In this embodiment, the circuit driving power supply supplied to the source signal line driving circuit is assumed to be one system, but two or more systems may be used, and a level shifter circuit may be inserted in a necessary portion.
[0178]
[Example 8]
In this embodiment, as an example of a method for manufacturing the active matrix liquid crystal display device described in Embodiments 1 to 7, a pixel TFT which is a switching element of the pixel portion and a driving circuit (source signal line driving) provided around the pixel portion. A method for manufacturing a TFT of a circuit, a gate signal line driver circuit, or the like over the same substrate will be described in detail according to the process. However, in order to simplify the description, a CMOS circuit, which is a basic configuration circuit, is illustrated as the drive circuit unit, and an n-channel TFT is illustrated as the pixel TFT unit.
[0179]
In FIG. 25A, a low alkali glass substrate or a quartz substrate can be used as the substrate (active matrix substrate) 6001. In this example, a low alkali glass substrate was used. In this case, heat treatment may be performed in advance at a temperature lower by about 10 to 20 ° C. than the glass strain point. A base film 6002 such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed on the surface of the substrate 6001 where a TFT is formed in order to prevent impurity diffusion from the substrate 6001. For example, SiH by plasma CVD method _Four , NH _Three , N ₂ A silicon oxynitride film made from O is 100 nm, similarly SiH _Four , N ₂ A silicon oxynitride film formed from O is stacked to a thickness of 200 nm.
[0180]
Next, a semiconductor film 6003a having an amorphous structure with a thickness of 20 to 150 nm (preferably 30 to 80 nm) is formed by a known method such as a plasma CVD method or a sputtering method. In this embodiment, an amorphous silicon film is formed to a thickness of 54 nm by plasma CVD. As the semiconductor film having an amorphous structure, there are an amorphous semiconductor film and a microcrystalline semiconductor film, and a compound semiconductor film having an amorphous structure such as an amorphous silicon germanium film may be applied. Further, since the base film 6002 and the amorphous silicon film 6003a can be formed by the same film formation method, they may be formed continuously. In that case, after the base film is formed, it is possible to prevent contamination of the surface by not exposing it to the air atmosphere, and it is possible to reduce variations in characteristics and threshold voltage of the TFT to be manufactured (see FIG. 25 (A)).
[0181]
Then, a crystalline silicon film 6003b is formed from the amorphous silicon film 6003a using a known crystallization technique. For example, a laser crystallization method or a thermal crystallization method (solid phase growth method) may be applied. Here, in accordance with the technique disclosed in Japanese Patent Laid-Open No. 7-130552, the crystallization method using a catalytic element is used for crystallization. A quality silicon film 6003b was formed. Prior to the crystallization process, depending on the hydrogen content of the amorphous silicon film, a heat treatment is performed at 400 to 500 ° C. for about 1 hour to reduce the hydrogen content to 5 atom% or less before crystallization. desirable. When the amorphous silicon film is crystallized, the rearrangement of atoms occurs and the amorphous silicon film is densified. Therefore, the thickness of the crystalline silicon film to be produced is larger than the initial thickness of the amorphous silicon film (54 nm in this embodiment). Also decreases by about 1 to 15% (FIG. 25B).
[0182]
Then, the crystalline silicon film 6003b is patterned into an island shape to form island-like semiconductor layers 6004 to 6007. Thereafter, a mask layer 6008 made of a silicon oxide film having a thickness of 50 to 150 nm is formed by plasma CVD or sputtering. (FIG. 25C).
[0183]
Then, a resist mask 6009 is provided, and 1 × 10 6 is formed on the entire surface of the island-like semiconductor layers 6005 to 6007 where n-channel TFTs are to be formed. ¹⁶ ~ 5x10 ¹⁷ atoms / cm ^Three Boron (B) is added as an impurity element imparting p-type at a moderate concentration. The boron (B) is added for the purpose of controlling the threshold voltage. Boron (B) may be added by an ion doping method, or may be added simultaneously with the formation of an amorphous silicon film. The addition of boron (B) here is not always necessary (FIG. 25D). Thereafter, the resist mask 6009 is removed.
[0184]
In order to form the LDD region of the n-channel TFT of the driver circuit, an impurity element imparting n-type conductivity is selectively added to the island-shaped semiconductor layers 6010 to 6012. Therefore, resist masks 6013 to 6016 are formed in advance. As the impurity element imparting n-type conductivity, phosphorus (P) or arsenic (As) may be used. Here, phosphorous (PH) is added to add phosphorus (P). _Three ) Was applied. The formed impurity regions 6017 and 6018 have a phosphorus (P) concentration of 2 × 10 ¹⁶ ~ 5x10 ¹⁹ atoms / cm ^Three It may be in the range. In this specification, the concentration of an impurity element imparting n-type contained in the impurity regions 6017 to 6019 formed here is defined as (n ^- ). The impurity region 6019 is a semiconductor layer for forming a storage capacitor of the pixel portion, and phosphorus (P) is added to this region at the same concentration (FIG. 26A). Thereafter, the resist masks 6013 to 6016 are removed.
[0185]
Next, after removing the mask layer 6008 with hydrofluoric acid or the like, a step of activating the impurity element added in FIGS. 25D and 26A is performed. The activation can be performed by a heat treatment for 1 to 4 hours in a nitrogen atmosphere at 500 to 600 ° C. or a laser activation method. Moreover, you may carry out using both together. In this embodiment, a laser activation method is used. As the laser light, KrF excimer laser light (wavelength 248 nm) is used. In this embodiment, the shape of the laser beam is processed into a linear beam, and the oscillation frequency is 5 to 50 Hz, and the energy density is 100 to 500 mJ / cm. ² As described above, the entire surface of the substrate on which the island-shaped semiconductor layer is formed is processed by scanning the linear beam with an overlap ratio of 80 to 98%. Note that the laser light irradiation conditions are not limited and can be appropriately determined.
[0186]
Then, the gate insulating film 6020 is formed with an insulating film containing silicon with a thickness of 10 to 150 nm by a plasma CVD method or a sputtering method. For example, a silicon oxynitride film is formed with a thickness of 120 nm. As the gate insulating film, another insulating film containing silicon may be used as a single layer or a stacked structure. (Fig. 26 (B))
[0187]
Next, a first conductive layer is formed to form a gate electrode. The first conductive layer may be formed as a single layer, but may have a laminated structure such as two layers or three layers as necessary. In this example, a conductive layer (A) 6021 made of a conductive nitride metal film and a conductive layer (B) 6022 made of a metal film were laminated. The conductive layer (B) 6022 is an element selected from tantalum (Ta), titanium (Ti), molybdenum (Mo), and tungsten (W), an alloy containing the element as a main component, or an alloy film in which the elements are combined. (Typically, a Mo—W alloy film or a Mo—Ta alloy film). The conductive layer (A) 6021 is a tantalum nitride (TaN), tungsten nitride (WN), titanium nitride (TiN) film, or nitride. It is made of molybdenum (MoN). Alternatively, tungsten silicide, titanium silicide, or molybdenum silicide may be applied to the conductive layer (A) 6021 as an alternative material. In the conductive layer (B), it is preferable to reduce the concentration of impurities contained in order to reduce resistance, and in particular, the oxygen concentration is preferably 30 ppm or less. For example, tungsten (W) can realize a specific resistance value of 20 μΩcm or less by setting the oxygen concentration to 30 ppm or less.
[0188]
The conductive layer (A) 6021 may be 10 to 50 nm (preferably 20 to 30 nm), and the conductive layer (B) 6022 may be 200 to 400 nm (preferably 250 to 350 nm). In this embodiment, a 30 nm thick tantalum nitride film is used for the conductive layer (A) 6021 and a 350 nm Ta film is used for the conductive layer (B) 6022, both of which are formed by sputtering. In film formation by this sputtering method, if an appropriate amount of Xe or Kr is added to the sputtering gas Ar, the internal stress of the film to be formed can be relaxed and the film can be prevented from peeling. Although not shown, it is effective to form a silicon film doped with phosphorus (P) with a thickness of about 2 to 20 nm under the conductive layer (A) 6021. This improves adhesion and prevents oxidation of the conductive film formed thereon, and at the same time, an alkali metal element contained in a trace amount in the conductive layer (A) or the conductive layer (B) diffuses into the gate insulating film 6020. Can be prevented (FIG. 26C).
[0189]
Next, resist masks 6023 to 6027 are formed, and the conductive layers (A) 6021 and (B) 6022 are etched together to form gate electrodes 6028 to 6031 and capacitor wirings 6032. The gate electrodes 6028 to 6031 and the capacitor wiring 6032 are integrally formed of 6028a to 6032a made of a conductive layer (A) and 6028b to 6032b made of a conductive layer (B). At this time, the gate electrodes 6028 to 6030 of the TFTs constituting the driver circuit are formed so as to overlap part of the impurity regions 6017 and 6018 with the gate insulating film 6020 interposed therebetween (FIG. 26D).
[0190]
Next, a step of adding an impurity element imparting p-type is performed in order to form a source region and a drain region of the p-channel TFT of the driver circuit. Here, impurity regions are formed in a self-aligning manner using the gate electrode 6028 as a mask. At this time, a region where the n-channel TFT is formed is covered with a resist mask 6033. And diborane (B ₂ H ₆ An impurity region 6034 was formed by an ion doping method using). The boron (B) concentration in this region is 3 × 10 ²⁰ ~ 3x10 ^{twenty one} atoms / cm ^Three To be. Thereafter, the resist mask 6033 is removed. In this specification, the concentration of the impurity element imparting p-type contained in the impurity region 6034 formed here (p ⁺⁺ ) (FIG. 27A).
[0191]
Next, in the n-channel TFT, an impurity region functioning as a source region or a drain region was formed. Resist masks 6035 to 6037 were formed, and an impurity element imparting n-type conductivity was added to form impurity regions 6038 to 6042. This is the phosphine (PH _Three ), And the phosphorus (P) concentration in this region is 1 × 10 ²⁰ ~ 1x10 ^{twenty one} atoms / cm ^Three It was. In this specification, the concentration of the impurity element imparting n-type contained in the impurity regions 6038 to 6042 formed here is defined as (n ⁺ ) (FIG. 27B).
[0192]
The impurity regions 6039 to 6042 already contain phosphorus (P) or boron (B) added in the previous step, but phosphorus (P) is added at a sufficiently higher concentration than that. The influence of phosphorus (P) or boron (B) added in the previous step may not be considered. Further, since the phosphorus (P) concentration added to the impurity region 6038 is 1/2 to 1/3 of the boron (B) concentration added in FIG. 27A, p-type conductivity is ensured, and TFT characteristics are obtained. It had no effect on.
[0193]
After removing the resist masks 6035 to 6037, an impurity addition step for imparting n-type for forming an LDD region of the n-channel TFT in the pixel portion was performed. Here, an impurity element imparting n-type in a self-aligning manner is added by an ion doping method using the gate electrode 6031 as a mask. The concentration of phosphorus (P) to be added is 1 × 10 ¹⁶ ~ 5x10 ¹⁸ atoms / cm ^Three By adding the impurity element at a concentration lower than that of the impurity element added in FIGS. 26A, 27A, and 27B, substantially only impurity regions 6043 and 6044 are formed. The In this specification, the concentration of an impurity element imparting n-type contained in the impurity regions 6043 and 6044 is defined as (n ^- ). (Fig. 27 (C))
[0194]
Thereafter, a heat treatment step is performed to activate the impurity element imparting n-type or p-type added at each concentration. This step can be performed by a furnace annealing method, a laser annealing method, or a rapid thermal annealing method (RTA method). Here, the activation process was performed by furnace annealing. The heat treatment is performed at 400 to 800 ° C., typically 500 to 600 ° C. in a nitrogen atmosphere having an oxygen concentration of 1 ppm or less, preferably 0.1 ppm or less. In this embodiment, the heat treatment is performed at 500 ° C. for 4 hours. went. Further, in the case where a substrate 6001 having heat resistance such as a quartz substrate is used, heat treatment may be performed at 800 ° C. for 1 hour, and activation of the impurity element, impurity region to which the impurity element is added, and A junction with the channel formation region can be formed satisfactorily. Note that this effect may not be obtained when an interlayer film is formed in order to prevent the peeling of Ta, which is the gate electrode.
[0195]
In this heat treatment, conductive films (C) 6028c to 6032c are formed with a thickness of 5 to 80 nm from the surface of the metal films 6028b to 6032b forming the gate electrodes 6028 to 6031 and the capacitor wiring 6032. For example, when the conductive layers (B) 6028b to 6032b are tungsten (W), tungsten nitride (WN) can be formed, and when tantalum (Ta) is used, tantalum nitride (TaN) can be formed. The conductive layers (C) 6028c to 6032c can be formed in the same manner even when the gate electrodes 6028 to 6031 and the capacitor wiring 6032 are exposed to a plasma atmosphere containing nitrogen using nitrogen or ammonia. Further, a heat treatment was performed at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen to perform a step of hydrogenating the island-shaped semiconductor layer. This step is a step of terminating dangling bonds in the semiconductor layer with thermally excited hydrogen. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma or hydrogenated plasma) may be performed.
[0196]
In the case where the island-shaped semiconductor layer was formed from an amorphous silicon film by a crystallization method using a catalytic element, a trace amount of the catalytic element remained in the island-shaped semiconductor layer. Of course, it is possible to complete the TFT even in such a state, but it is more preferable to remove at least the remaining catalyst element from the channel formation region. As one of means for removing the catalyst element, there is a means for utilizing the gettering action by phosphorus (P). The concentration of phosphorus (P) necessary for gettering is the impurity region (n) formed in FIG. ⁺ The catalytic element could be gettered from the channel formation region of the n-channel TFT and the p-channel TFT by the heat treatment in the activation process performed here (FIG. 27D). .
[0197]
After the activation and hydrogenation steps are completed, a second conductive film is formed as a gate wiring (gate signal line). This second conductive film includes a conductive layer (D) mainly composed of aluminum (Al) or copper (Cu), which is a low resistance material, and titanium (Ti), tantalum (Ta), tungsten (W), molybdenum. It is good to form with the conductive layer (E) which consists of (Mo). In this embodiment, an aluminum (Al) film containing 0.1 to 2% by weight of titanium (Ti) is formed as the conductive layer (D) 6045, and a titanium (Ti) film is formed as the conductive layer (E) 6046. The conductive layer (D) 6045 may be 200 to 400 nm (preferably 250 to 350 nm), and the conductive layer (E) 6046 may be 50 to 200 (preferably 100 to 150 nm). (FIG. 28 (A))
[0198]
Then, the conductive layer (E) 6046 and the conductive layer (D) 6045 are etched to form gate wirings (gate signal lines) 6047 and 6048 connected to the gate electrodes. A capacitor wiring 6049 was formed. The etching process starts with SiCl _Four And Cl ₂ And BCl _Three The conductive layer (E) is removed from the surface of the conductive layer (E) to the middle of the conductive layer (D) by a dry etching method using a mixed gas and then the conductive layer (D) is removed by wet etching with a phosphoric acid-based etching solution. As a result, the gate wiring (gate signal line) could be formed while maintaining selective processability with the base.
[0199]
The first interlayer insulating film 6050 is formed of a silicon oxide film or a silicon oxynitride film with a thickness of 500 to 1500 nm, and then a contact hole reaching the source region or the drain region formed in each island-shaped semiconductor layer is formed. Then, source wirings (source signal lines) 6051 to 6054 and drain wirings 6055 to 6058 are formed. Although not shown, in this embodiment, this electrode is a laminated film having a three-layer structure in which a Ti film is 100 nm, an aluminum film containing Ti is 300 nm, and a Ti film is 150 nm continuously formed by sputtering.
[0200]
Next, a silicon nitride film, a silicon oxide film, or a silicon nitride oxide film is formed as the passivation film 6059 with a thickness of 50 to 500 nm (typically 100 to 300 nm). When the hydrogenation treatment was performed in this state, a favorable result was obtained for improving the characteristics of the TFT. For example, heat treatment may be performed at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen, or the same effect can be obtained by using a plasma hydrogenation method. Note that an opening may be formed in the passivation film 6059 at a position where a contact hole for connecting the pixel electrode and the drain wiring is formed later. (Fig. 28 (C))
[0201]
Thereafter, a second interlayer insulating film 6060 made of an organic resin is formed to a thickness of 1.0 to 1.5 μm. As the organic resin, polyimide, acrylic, polyamide, polyimide amide, BCB (benzocyclobutene), or the like can be used. Here, it was formed by baking at 300 ° C. using a type of polyimide that is thermally polymerized after being applied to the substrate. Then, a contact hole reaching the drain wiring 6058 is formed in the second interlayer insulating film 6060, and pixel electrodes 6061 and 6062 are formed. The pixel electrode may be a transparent conductive film in the case of a transmissive liquid crystal display device, and may be a metal film in the case of a reflective liquid crystal display device. In this embodiment, an indium tin oxide (ITO) film having a thickness of 100 nm is formed by sputtering to form a transmissive liquid crystal display device. (Fig. 29)
[0202]
In this way, a substrate having the TFT of the driving circuit and the pixel TFT of the pixel portion on the same substrate was completed. A p-channel TFT 6101, a first n-channel TFT 6102, and a second n-channel TFT 6103 are formed in the driver circuit, and a pixel TFT 6104 and a storage capacitor 6105 are formed in the pixel portion. In this specification, such a substrate is referred to as an active matrix substrate for convenience.
[0203]
The p-channel TFT 6101 of the driver circuit includes a channel formation region 6106, source regions 6107a and 6107b, and drain regions 6108a and 6108b in an island-shaped semiconductor layer 6004. In the first n-channel TFT 6102, an LDD region 6110 that overlaps the island-shaped semiconductor layer 6005 with the channel formation region 6109 and the gate electrode 6029 (hereinafter, such an LDD region is referred to as Lov), a source region 6111, and a drain region 6112. have. The length of the Lov region in the channel length direction is 0.5 to 3.0 μm, preferably 1.0 to 1.5 μm. The second n-channel TFT 6103 has a channel formation region 6113, LDD regions 6114 and 6115, a source region 6116, and a drain region 6117 in the island-shaped semiconductor layer 6006. The LDD region is formed with an LDD region that does not overlap the Lov region and the gate electrode 6030 (hereinafter, such LDD region is referred to as Loff), and the length of the Loff region in the channel length direction is 0.3-2. It is 0 μm, preferably 0.5 to 1.5 μm. The pixel TFT 6104 has channel formation regions 6118 and 6119, Loff regions 6120 to 6123, and source or drain regions 6124 to 6126 in an island-shaped semiconductor layer 6007. The length of the Loff region in the channel length direction is 0.5 to 3.0 μm, preferably 1.5 to 2.5 μm. Further, the storage capacitor 6105 includes capacitor wirings 6032 and 6049, an insulating film made of the same material as the gate insulating film, and a semiconductor layer 6127 which is connected to the drain region 6126 of the pixel TFT 6104 and to which an impurity element imparting n-type conductivity is added. Is formed. In FIG. 29, the pixel TFT 6104 has a double gate structure, but it may have a single gate structure or a multi-gate structure provided with a plurality of gate electrodes.
[0204]
As described above, in this embodiment, the structure of the TFT constituting each circuit is optimized according to the specifications required by the pixel TFT and the drive circuit, and the operation performance and reliability of the image display apparatus can be improved. be able to.
[0205]
Next, a process of manufacturing a transmissive liquid crystal display device based on the active matrix substrate manufactured by the above process will be described.
[0206]
Refer to FIG. An alignment film 6201 is formed on the active matrix substrate in the state shown in FIG. In this embodiment, polyimide is used for the alignment film 6201. Next, a counter substrate is prepared. The counter substrate includes a glass substrate 6202, a light shielding film 6203, a counter electrode 6204 made of a transparent conductive film, and an alignment film 6205.
[0207]
In this embodiment, a polyimide film in which liquid crystal molecules are aligned in parallel to the substrate is used for the alignment film. Note that after the alignment film is formed, a rubbing process is performed so that the liquid crystal molecules are aligned in parallel with a certain pretilt angle.
[0208]
Next, the active matrix substrate and the counter substrate that have undergone the above-described steps are bonded to each other through a sealing material, a spacer (both not shown), and the like by a known cell assembling step. Thereafter, liquid crystal 6206 is injected between both the substrates and completely sealed with a sealant (not shown). Therefore, a transmissive liquid crystal display device as shown in FIG. 30 is completed.
[0209]
Note that the TFT formed by the above process has a top gate structure, but the present invention can be applied to a TFT having a bottom gate structure and other structures.
[0210]
In addition, the display device produced by the above process is a transmissive liquid crystal display device, but the present invention can also be applied to a reflective liquid crystal display device.
[0211]
The present invention can also be applied to a light-emitting device that is a self-luminous display device using a light-emitting material instead of a liquid crystal material.
[0212]
[Example 9]
In this embodiment, a manufacturing example in the case where the present invention is applied to a light-emitting device instead of the active matrix liquid crystal display device described in Embodiments 1 to 7 will be described.
[0213]
FIG. 31A is a top view of a light-emitting device to which the present invention is applied, and FIG. 31B is a cross-sectional view of the light-emitting device cut along AA ′ shown in FIG. In FIG. 31A, reference numeral 4010 denotes a substrate, 4011 denotes a pixel portion, 4012 denotes a source signal line driver circuit, and 4013 denotes a gate signal line driver circuit. Each driver circuit reaches an FPC 4017 through wirings 4014 to 4016, and is externally connected. Connected to the device.
[0214]
At this time, a cover material 4600, a sealing material (also referred to as a housing material) 4100, and a sealing material (second sealing material) 4101 are provided so as to surround at least the pixel portion, preferably the drive circuit and the pixel portion.
[0215]
Further, as shown in FIG. 31B, a driving circuit TFT (here, a CMOS circuit in which an n-channel TFT and a p-channel TFT are combined) is shown over a substrate 4010 and a base film 4021. ) 4022 and the pixel portion TFT 4023 (however, only the TFT for controlling the current to the light emitting element is shown here). These TFTs may have a known structure (top gate structure or bottom gate structure).
[0216]
When a driver circuit TFT 4022 and a pixel portion TFT 4023 are completed using a known manufacturing method, a transparent conductive layer electrically connected to the drain of the pixel portion TFT 4023 on an interlayer insulating film (planarization film) 4026 made of a resin material. A pixel electrode 4027 made of a film is formed. As the transparent conductive film, a compound of indium oxide and tin oxide (referred to as ITO) or a compound of indium oxide and zinc oxide can be used. Then, after the pixel electrode 4027 is formed, an insulating film 4028 is formed, and an opening is formed over the pixel electrode 4027.
[0217]
Next, the light emitting layer 4029 is formed. The light-emitting layer 4029 may have a stacked structure or a single-layer structure by freely combining known light-emitting materials (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, or electron injection layer). A known technique may be used to determine the structure. The light emitting material includes a low molecular weight material and a high molecular weight (polymer) material. When a low molecular material is used, a vapor deposition method is used. When a high molecular material is used, a simple method such as a spin coating method, a printing method, or an ink jet method can be used.
[0218]
In this embodiment, the light emitting layer is formed by vapor deposition using a shadow mask. Color display is possible by forming a light emitting layer (a red light emitting layer, a green light emitting layer, and a blue light emitting layer) capable of emitting light having different wavelengths for each pixel using a shadow mask. In addition, there are a method in which a color conversion layer (CCM) and a color filter are combined, and a method in which a white light emitting layer and a color filter are combined, but either method may be used. Needless to say, a single color light emitting device can also be provided.
[0219]
After the light emitting layer 4029 is formed, a cathode 4030 is formed thereon. It is desirable to exclude moisture and oxygen present at the interface between the cathode 4030 and the light emitting layer 4029 as much as possible. Therefore, it is necessary to devise such that the light emitting layer 4029 and the cathode 4030 are continuously formed in vacuum, or the light emitting layer 4029 is formed in an inert atmosphere and the cathode 4030 is formed without being released to the atmosphere. In this embodiment, the above-described film formation is possible by using a multi-chamber type (cluster tool type) film formation apparatus.
[0220]
In this embodiment, a stacked structure of a LiF (lithium fluoride) film and an Al (aluminum) film is used as the cathode 4030. Specifically, a LiF (lithium fluoride) film having a thickness of 1 nm is formed on the light emitting layer 4029 by vapor deposition, and an aluminum film having a thickness of 300 nm is formed thereon. Of course, you may use the MgAg electrode which is a well-known cathode material. The cathode 4030 is connected to the wiring 4016 in the region indicated by 4031. A wiring 4016 is a power supply line for applying a predetermined voltage to the cathode 4030, and is connected to the FPC 4017 through a conductive paste material 4032.
[0221]
In order to electrically connect the cathode 4030 and the wiring 4016 in the region indicated by 4031, it is necessary to form contact holes in the interlayer insulating film 4026 and the insulating film 4028. These may be formed when the interlayer insulating film 4026 is etched (when a pixel electrode contact hole is formed) or when the insulating film 4028 is etched (when an opening is formed before the light emitting layer is formed). In addition, when the insulating film 4028 is etched, the interlayer insulating film 4026 may be etched all at once. In this case, if the interlayer insulating film 4026 and the insulating film 4028 are the same resin material, the shape of the contact hole can be improved.
[0222]
A passivation film 4603, a filler 4604, and a cover material 4600 are formed so as to cover the surface of the light-emitting element formed in this manner.
[0223]
Further, a sealing material 4100 is provided inside the cover material 4600 and the substrate 4010 so as to surround the light emitting element portion, and a sealing material (second sealing material) 4101 is formed outside the sealing material 4100.
[0224]
At this time, the filler 4604 also functions as an adhesive for bonding the cover material 4600. As the filler 4604, PVC (polyvinyl chloride), epoxy resin, silicone resin, PVB (polyvinyl butyral), or EVA (ethylene vinyl acetate) can be used. It is preferable to provide a desiccant inside the filler 4604 because the moisture absorption effect can be maintained.
[0225]
Further, a spacer may be contained in the filler 4604. At this time, the spacer may be a granular material made of BaO or the like, and the spacer itself may be hygroscopic.
[0226]
In the case where a spacer is provided, the passivation film 4603 can relieve the spacer pressure. In addition to the passivation film, a resin film for relaxing the spacer pressure may be provided.
[0227]
Further, as the cover material 4600, a glass plate, an aluminum plate, a stainless steel plate, an FRP (Fiberglass-Reinforced Plastics) plate, a PVF (polyvinyl fluoride) film, a mylar film, a polyester film, or an acrylic film can be used. Note that in the case of using PVB or EVA as the filler 4604, it is preferable to use a sheet having a structure in which an aluminum foil of several tens of μm is sandwiched between PVF films or Mylar films.
[0228]
However, the cover material 4600 needs to have translucency depending on the light emission direction (light emission direction) from the light emitting element.
[0229]
The wiring 4016 is electrically connected to the FPC 4017 through a gap between the sealing material 4100 and the sealing material 4101 and the substrate 4010. Note that although the wiring 4016 has been described here, the other wirings 4014 and 4015 are electrically connected to the FPC 4017 through the sealing material 4100 and the sealing material 4101 in the same manner.
[0230]
In this embodiment, the cover material 4600 is adhered after the filler 4604 is provided, and the sealing material 4100 is attached so as to cover the side surface (exposed surface) of the filler 4604. However, the cover material 4600 and the sealing material 4100 are attached to each other. The filler 4604 may be provided after the attachment. In this case, a filler inlet that leads to a gap formed by the substrate 4010, the cover material 4600, and the sealing material 4100 is provided. The voids are in a vacuum state (10 ^-2 The Torr is equal to or less than Torr), and the inlet is immersed in a water tank containing a filler, and then the pressure outside the gap is made higher than the pressure inside the gap to fill the filler into the gap.
[0231]
[Example 10]
In this example, an example of manufacturing a light-emitting device having a different form from that of Example 9 using the present invention will be described with reference to FIGS. The same reference numerals as those in FIGS. 31A and 31B indicate the same parts, and the description thereof is omitted.
[0232]
FIG. 32A is a top view of the light-emitting device of this example, and FIG. 32B shows a cross-sectional view taken along line AA ′ of FIG.
[0233]
According to Example 9, a passivation film 4603 is formed to cover the surface of the light emitting element.
[0234]
Further, a filler 4604 is provided so as to cover the light emitting element. The filler 4604 also functions as an adhesive for bonding the cover material 4600. As the filler 4604, PVC (polyvinyl chloride), epoxy resin, silicone resin, PVB (polyvinyl butyral), or EVA (ethylene vinyl acetate) can be used. It is preferable to provide a desiccant inside the filler 4604 because the moisture absorption effect can be maintained.
[0235]
Further, a spacer may be contained in the filler 4604. At this time, the spacer may be a granular material made of BaO or the like, and the spacer itself may be hygroscopic.
[0236]
In the case where a spacer is provided, the passivation film 4603 can relieve the spacer pressure. In addition to the passivation film, a resin film for relaxing the spacer pressure may be provided.
[0237]
Further, as the cover material 4600, a glass plate, an aluminum plate, a stainless steel plate, an FRP (Fiberglass-Reinforced Plastics) plate, a PVF (polyvinyl fluoride) film, a mylar film, a polyester film, or an acrylic film can be used. Note that in the case of using PVB or EVA as the filler 4604, it is preferable to use a sheet having a structure in which an aluminum foil of several tens of μm is sandwiched between PVF films or Mylar films.
[0238]
However, the cover material 4600 needs to have translucency depending on the light emission direction (light emission direction) from the light emitting element.
[0239]
Next, after the cover material 4600 is bonded using the filler 4604, the frame material 4601 is attached so as to cover the side surface (exposed surface) of the filler 4604. The frame material 4601 is bonded by a sealing material (functioning as an adhesive) 4602. At this time, a photocurable resin is preferably used as the sealing material 4602, but a thermosetting resin may be used if the heat resistance of the light emitting layer permits. Note that the sealing material 4602 is preferably a material that does not transmit moisture and oxygen as much as possible. Further, a desiccant may be added inside the sealing material 4602.
[0240]
The wiring 4016 is electrically connected to the FPC 4017 through a gap between the sealing material 4602 and the substrate 4010. Note that although the wiring 4016 has been described here, the other wirings 4014 and 4015 are electrically connected to the FPC 4017 through the sealing material 4602 in the same manner.
[0241]
In this embodiment, the cover material 4600 is adhered after the filler 4604 is provided, and the frame material 4601 is attached so as to cover the side surface (exposed surface) of the filler 4604. However, the cover material 4600 and the frame material 4601 are attached. The filler 4604 may be provided after the attachment. In this case, an injection port for a filler that leads to a gap formed by the substrate 4010, the cover material 4600, and the frame material 4601 is provided. The voids are in a vacuum state (10 ^-2 The Torr is equal to or less than Torr), and the inlet is immersed in a water tank containing a filler, and then the pressure outside the gap is made higher than the pressure inside the gap to fill the filler into the gap.
[0242]
[Example 11]
Here, FIG. 33 shows a more detailed cross-sectional structure of the pixel portion in the light-emitting device, FIG. 34A shows a top surface structure, and FIG. 34B shows a circuit diagram. 33, 34 (A), and 34 (B) use the same reference numerals and may be referred to each other.
[0243]
In FIG. 33, an n-channel TFT formed by a known method is used as a switching TFT 4502 provided over a substrate 4501. In this embodiment, a double gate structure is used. However, there is no significant difference in structure and manufacturing process, and thus description thereof is omitted. However, the double gate structure substantially has a structure in which two TFTs are connected in series, and there is an advantage that the off-current value can be reduced. Although the double gate structure is used in this embodiment, a single gate structure may be used, and a triple gate structure or a multi-gate structure having more gates may be used. Alternatively, a p-channel TFT formed by a known method may be used.
[0244]
Further, an n-channel TFT formed by a known method is used as the current control TFT 4503. The switching TFT 4502 has 34 source lines (source signal lines). The drain wiring 35 of the switching TFT 4502 is electrically connected to the gate electrode 37 of the current control TFT by the wiring 36. A wiring indicated by 38 is a gate wiring (gate signal line) that electrically connects the gate electrodes 39a and 39b of the switching TFT 4502.
[0245]
Since the current control TFT 4503 is an element that controls the amount of current flowing through the light emitting element, a large amount of current flows through the current control TFT 4503, and is also an element that has a high risk of deterioration due to heat or hot carriers. Therefore, a structure in which an LDD region is provided on the drain side of the current control TFT 4503 so as to overlap the gate electrode through a gate insulating film is extremely effective.
[0246]
In this embodiment, the current control TFT 4503 is shown as a single gate structure, but a multi-gate structure in which a plurality of TFTs are connected in series may be used. Further, a structure may be employed in which a plurality of TFTs are connected in parallel to substantially divide the channel formation region into a plurality of portions so that heat can be emitted with high efficiency. Such a structure is effective as a countermeasure against deterioration due to heat.
[0247]
Further, as shown in FIG. 34A, the wiring 36 which becomes the gate electrode 37 of the current control TFT 4503 is electrically connected to the drain wiring 40 of the current control TFT 4503 through an insulating film in a region indicated by 4504. Overlaps with the power supply line 4506. At this time, a capacitor is formed in a region indicated by 4504 and functions as a holding capacitor for holding a voltage applied to the gate electrode 37 of the current control TFT 4503. The storage capacitor 4504 is formed between a semiconductor film 4507 electrically connected to the power supply line 4506, an insulating film (not shown) in the same layer as the gate insulating film, and the wiring 36. A capacitor formed by the wiring 36, the same layer (not shown) as the first interlayer insulating film, and the power supply line 4506 can also be used as the storage capacitor. Note that the drain of the current control TFT is connected to a power supply line (power supply line) 4506, and a constant voltage is always applied.
[0248]
A first passivation film 41 is provided on the switching TFT 4502 and the current control TFT 4503, and a planarizing film 42 made of a resin insulating film is formed thereon. It is very important to flatten the step due to the TFT using the flattening film 42. Since the light emitting layer formed later is very thin, the presence of a step may cause a light emission failure. Therefore, it is desirable to planarize the pixel electrode before forming it so that the light emitting layer can be formed as flat as possible.
[0249]
Reference numeral 43 denotes a pixel electrode (a cathode of a light emitting element) made of a highly reflective conductive film, which is electrically connected to the drain of the current control TFT 4503. As the pixel electrode 43, it is preferable to use a low-resistance conductive film such as an aluminum alloy film, a copper alloy film, or a silver alloy film, or a laminated film thereof. Of course, a laminated structure with another conductive film may be used.
[0250]
A light emitting layer 45 is formed in a groove (corresponding to a pixel) formed by banks 44a and 44b formed of an insulating film (preferably resin). Note that in FIG. 34A, some banks are omitted in order to clarify the position of the storage capacitor 4504, and only the banks 44a and 44b are illustrated, but a power supply line 4506 and a source wiring (source signal line) are shown. ) 34 is provided between the power supply line 4506 and the source wiring (source signal line) 34 so as to partially cover. Although only two pixels are shown here, a light emitting layer corresponding to each color of R (red), G (green), and B (blue) may be formed separately. A π-conjugated polymer material is used as the organic light emitting material for the light emitting layer. Typical polymer materials include polyparaphenylene vinylene (PPV), polyvinyl carbazole (PVK), and polyfluorene.
[0251]
There are various types of PPV organic light-emitting materials. For example, “H. Shenk, H. Becker, O. Gelsen, E. Kluge, W. Kreuder, and H. Spreitzer,“ Polymers for Light Emitting ”. Materials such as those described in “Diodes”, Euro Display, Proceedings, 1999, p. 33-37 ”and Japanese Patent Laid-Open No. 10-92576 may be used.
[0252]
As a specific light emitting layer, cyanopolyphenylene vinylene may be used for a light emitting layer that emits red light, polyphenylene vinylene may be used for a light emitting layer that emits green light, and polyphenylene vinylene or polyalkylphenylene may be used for a light emitting layer that emits blue light. The film thickness may be 30 to 150 nm (preferably 40 to 100 nm).
[0253]
However, the above example is an example of an organic light emitting material that can be used as a light emitting layer, and it is not absolutely necessary to limit to this. A light emitting layer (a layer for emitting light and moving carriers therefor) may be formed by freely combining a light emitting layer, a charge transport layer, or a charge injection layer.
[0254]
For example, in this embodiment, an example in which a polymer material is used as the light emitting layer is shown, but a low molecular weight organic light emitting material may be used. It is also possible to use an inorganic material such as silicon carbide for the charge transport layer or the charge injection layer. Known materials can be used for these organic light emitting materials and inorganic materials.
[0255]
In this embodiment, a light emitting layer having a laminated structure in which a hole injection layer 46 made of PEDOT (polythiophene) or PAni (polyaniline) is provided on the light emitting layer 45 is used. An anode 47 made of a transparent conductive film is provided on the hole injection layer 46. In the case of the present embodiment, since the light generated in the light emitting layer 45 is emitted toward the upper surface side (upward of the TFT), the anode must be translucent. As the transparent conductive film, a compound of indium oxide and tin oxide or a compound of indium oxide and zinc oxide can be used, but it is possible to form after forming a light-emitting layer or hole injection layer with low heat resistance. What can form into a film at low temperature as much as possible is preferable.
[0256]
When the anode 47 is formed, the light emitting element 4505 is completed. Note that the light-emitting element 4505 here refers to a capacitor formed by the pixel electrode (cathode) 43, the light-emitting layer 45, the hole injection layer 46, and the anode 47. As shown in FIG. 34A, since the pixel electrode 43 substantially matches the area of the pixel, the entire pixel functions as a light emitting element. Therefore, the use efficiency of light emission is very high, and a bright image display is possible.
[0257]
By the way, in the present embodiment, a second passivation film 48 is further provided on the anode 47. The second passivation film 48 is preferably a silicon nitride film or a silicon nitride oxide film. This purpose is to shut off the light emitting element from the outside, and has both the meaning of preventing deterioration due to oxidation of the organic light emitting material and the meaning of suppressing degassing from the organic light emitting material. This increases the reliability of the light emitting device.
[0258]
As described above, the light-emitting device of the present invention includes a pixel portion including a pixel having a structure as shown in FIG. 33, and includes a switching TFT having a sufficiently low off-state current value and a current control TFT resistant to hot carrier injection. . Therefore, a light emitting device having high reliability and capable of displaying a good image can be obtained.
[0259]
[Example 12]
In this embodiment, a structure in which the structure of the light-emitting element 4505 is inverted in the pixel portion described in Embodiment 11 will be described. FIG. 35 is used for the description. Note that the only difference from the structure of FIG. 33 is the light emitting element portion and the current control TFT, and other descriptions are omitted.
[0260]
In FIG. 35, a p-channel TFT formed by a known method is used as the current control TFT 4503.
[0261]
In this embodiment, a transparent conductive film is used as the pixel electrode (anode) 50. Specifically, a conductive film made of a compound of indium oxide and zinc oxide is used. Of course, a conductive film made of a compound of indium oxide and tin oxide may be used.
[0262]
Then, after banks 51a and 51b made of insulating films are formed, a light emitting layer 52 made of polyvinylcarbazole is formed by solution coating. An electron injection layer 53 made of potassium acetylacetonate (denoted as acacK) and a cathode 54 made of an aluminum alloy are formed thereon. In this case, the cathode 54 also functions as a passivation film. Thus, the light emitting element 4701 is formed.
[0263]
In the case of the present embodiment, the light generated in the light emitting layer 52 is emitted toward the substrate on which the TFT is formed, as indicated by the arrows.
[0264]
[Example 13]
In this embodiment, an example of a pixel having a structure different from the circuit diagram shown in FIG. 34B is shown in FIGS. In this embodiment, 4801 is the source wiring (source signal line) of the switching TFT 4802, 4803 is the gate wiring (gate signal line) of the switching TFT 4802, 4804 is the current control TFT, 4805 is the storage capacitor, 4806 and 4808. Is a power supply line and 4807 is a light emitting element.
[0265]
FIG. 36A illustrates an example in which the power supply line 4806 is shared between two pixels. That is, there is a feature in that the two pixels are formed so as to be symmetrical with respect to the power supply line 4806. In this case, since the number of power supply lines can be reduced, the pixel portion can be further refined.
[0266]
FIG. 36B shows an example in which the power supply line 4808 is provided in parallel with the gate wiring (gate signal line) 4803. Note that in FIG. 36B, the power supply line 4808 and the gate wiring (gate signal line) 4803 are provided so as not to overlap with each other; It can also provide so that it may overlap through a film | membrane. In this case, since the exclusive area can be shared by the power supply line 4808 and the gate wiring (gate signal line) 4803, the pixel portion can be further refined.
[0267]
In FIG. 36C, similarly to the structure of FIG. 36B, a power supply line 4808 is provided in parallel with the gate wiring (gate signal line) 4803, and two pixels are connected to the power supply line 4808. It is characterized in that it is formed so as to be symmetrical. It is also effective to provide the power supply line 4808 so as to overlap with any one of the gate wirings (gate signal lines) 4803. In this case, since the number of power supply lines can be reduced, the pixel portion can be further refined.
[0268]
[Example 14]
34A and 34B shown in Embodiment 11 has a structure in which a storage capacitor 4504 is provided in order to hold a voltage applied to the gate of the current control TFT 4503, but the storage capacitor 4504 may be omitted. It is. In the case of Example 11, an LDD region is provided on the drain side of the current control TFT 4503 so as to overlap the gate electrode with a gate insulating film interposed therebetween. In this overlapped region, a parasitic capacitance generally called a gate capacitance is formed, but this embodiment is characterized in that this parasitic capacitance is positively used in place of the holding capacitor 4504.
[0269]
Since the capacitance of the parasitic capacitance varies depending on the area where the gate electrode and the LDD region overlap, the capacitance of the parasitic capacitance is determined by the length of the LDD region included in the overlapping region.
[0270]
Similarly in the structures of FIGS. 36A, 36B, and 36C shown in Embodiment 13, the storage capacitor 4805 can be omitted.
[0271]
[Example 15]
In this embodiment, an electronic device incorporating an active matrix liquid crystal display device or a light emitting device using the driving method of the present invention will be described. Examples of these electronic devices include portable information terminals (electronic notebooks, mobile computers, mobile phones, etc.), video cameras, still cameras, personal computers, televisions, and the like. Examples of these are shown in FIGS. However, FIGS. 37, 38, and 39 are applied to the active matrix liquid crystal display device, and FIGS. 37 and 38 are applied to the light emitting device.
[0272]
FIG. 37A illustrates a mobile phone, which includes a main body 9001, an audio output portion 9002, an audio input portion 9003, a display portion 9004, operation switches 9005, and an antenna 9006. The present invention can be applied to the display portion 9004.
[0273]
FIG. 37B shows a video camera, which includes a main body 9101, a display portion 9102, an audio input portion 9103, operation switches 9104, a battery 9105, and an image receiving portion 9106. The present invention can be applied to the display portion 9102.
[0274]
FIG. 37C illustrates a mobile computer or a portable information terminal which is a kind of personal computer, which includes a main body 9201, a camera portion 9202, an image receiving portion 9203, operation switches 9204, and a display portion 9205. The present invention can be applied to the display portion 9205.
[0275]
FIG. 37D illustrates a head mounted display (goggles type display) which includes a main body 9301, a display portion 9302, and an arm portion 9303. The present invention can be applied to the display portion 9302.
[0276]
FIG. 37E illustrates a television set including a main body 9401, speakers 9402, a display portion 9403, a receiving device 9404, an amplifying device 9405, and the like. The present invention can be applied to the display portion 9403.
[0277]
FIG. 37F illustrates a portable book which includes a main body 9501, a display portion 9502, a storage medium 9504, an operation switch 9505, and an antenna 9506, and is stored on a mini disc (MD) or a DVD (Digital Versatile Disc). Data and data received by the antenna are displayed. The present invention can be applied to the display portion 9502.
[0278]
FIG. 38A illustrates a personal computer which includes a main body 9601, an image input portion 9602, a display portion 9603, and a keyboard 9604. The present invention can be applied to the display portion 9603.
[0279]
FIG. 38B shows a player using a recording medium (hereinafter referred to as a recording medium) on which a program is recorded. The player includes a main body 9701, a display portion 9702, a speaker portion 9703, a recording medium 9704, and operation switches 9705. This apparatus uses a DVD, CD, or the like as a recording medium, and can perform music appreciation, movie appreciation, games, and the Internet. The present invention can be applied to the display portion 9702.
[0280]
FIG. 38C illustrates a digital camera which includes a main body 9801, a display portion 9802, an eyepiece portion 9803, operation switches 9804, and an image receiving portion (not shown). The present invention can be applied to the display portion 9802.
[0281]
FIG. 38D illustrates a single-eye head mounted display which includes a display portion 9901 and a head mount portion 9902. The present invention can be applied to the display portion 9901. FIG.
[0282]
FIG. 39A illustrates a front type projector which includes a projection device 3601 and a screen 3602.
[0283]
FIG. 39B shows a rear projector, which includes a main body 3701, a projection device 3702, a mirror 3703, and a screen 3704.
[0284]
Note that FIG. 39C illustrates an example of the structure of the projection devices 3601 and 3702 in FIGS. 39A and 39B. The projection devices 3601 and 3702 include a light source optical system 3801, mirrors 3802, 3804 to 3806, a dichroic mirror 3803, a prism 3807, a liquid crystal display unit 3808, a phase difference plate 3809, and a projection optical system 3810. The projection optical system 3810 is composed of an optical system including a projection lens. In this embodiment, an example of a three-plate type is shown, but the present invention is not limited to this. For example, a single-plate type may be used. Further, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarization function, a film for adjusting a phase difference, or an IR film in the optical path indicated by an arrow in FIG. Good. The present invention can be applied to the liquid crystal display portion 3808.
[0285]
FIG. 39D is a diagram showing an example of the structure of the light source optical system 3801 in FIG. In this embodiment, the light source optical system 3801 includes a reflector 3811, a light source 3812, lens arrays 3813 and 3814, a polarization conversion element 3815, and a condenser lens 3816. Note that the light source optical system illustrated in FIG. 39D is an example and is not particularly limited. For example, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarization function, a film for adjusting a phase difference, or an IR film in the light source optical system.
[0286]
As described above, the applicable range of the present invention is extremely wide, and it can be applied to electronic devices in various fields using an image display device.
[0287]
【The invention's effect】
According to the driving method of the present invention, source line inversion driving and dot inversion driving can be performed in a method of driving a plurality of source signal lines with one D / A conversion circuit. Further, as in the third, fourth, and sixth embodiments, the polarity of the control signal or the power supply voltage of the gradation power supply line can be changed by devising the input method of the gradation power supply line switching control signal or the power supply voltage of the gradation power supply line. It is possible to lengthen the inversion period and reduce the burden on the circuit.
[0288]
In particular, as can be seen in the third, fourth, and sixth embodiments, the period for inverting the polarity of the power supply voltage of the control signal or the gradation power supply line in the dot inversion driving that generally expects high image quality is the source line inversion. The advantage of being as long as or longer than those in drive is great. Most effectively, the period of inverting the polarity of the control signal or the power supply voltage of the gradation power supply line in dot inversion driving can be extended to the same period as in the gate line inversion driving method. In other words, it is possible to enable dot inversion driving with the same period as the normal gate line inversion driving method.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a drive circuit according to Embodiments 1 and 3 of the present invention.
FIG. 2 is an example of operation timing according to the first embodiment of FIG. 1;
FIG. 3 is a schematic diagram of a drive circuit according to Embodiments 2 and 4 of the present invention.
FIG. 4 is an example of operation timing according to the second embodiment of FIG. 3;
FIG. 5 is an example of operation timing according to the third embodiment of FIG. 1;
FIG. 6 is an example of operation timing according to the fourth embodiment of FIG. 3;
FIG. 7 is a schematic diagram of a drive circuit according to Embodiments 5 and 6 of the present invention.
FIG. 8 is an example of operation timing according to the fifth embodiment of FIG. 7;
FIG. 9 is an example of operation timing according to the sixth embodiment of FIG. 7;
FIG. 10 is a schematic diagram of a drive circuit according to a seventh embodiment of the present invention.
FIG. 11 is an example of operation timing according to the seventh embodiment of FIG. 10;
FIG. 12 is a diagram showing the polarity of each pixel during source line inversion driving and dot inversion driving.
13 is a schematic diagram of a source signal line driving circuit according to Embodiment 1. FIG.
14 is a flip-flop circuit FF: (A), a basic latch circuit LAT: (B), and a connection switch SW: (C) for switching the connection between the gradation power supply line and the D / A converter circuit. FIG.
15 is a diagram showing a P / S conversion circuit A: (A) and a source line selection circuit A: (B) in FIG. 13;
FIG. 16 is a D / A conversion circuit diagram.
FIG. 17 is an example of operation timing according to the first embodiment.
18 is a schematic diagram of a source signal line drive circuit according to Embodiment 2. FIG.
FIG. 19 is an example of operation timing according to the second embodiment.
20 is a schematic diagram of a source signal line drive circuit according to Embodiment 5. FIG.
FIG. 21 is an example of operation timing according to the fifth embodiment.
FIG. 22 is a schematic diagram of a source signal line drive circuit according to a seventh embodiment.
23 is a P / S conversion circuit B: (A), a source line selection circuit B: (B) in FIG. 18, and a P / S conversion circuit C: (C), a source line selection circuit C in FIG. It is a figure which shows (D).
FIG. 24 is an example of operation timing according to the seventh embodiment.
FIG. 25 is a diagram showing manufacturing process examples of active matrix liquid crystal display devices according to Examples 1 to 7;
FIG. 26 is a diagram showing manufacturing process examples of active matrix liquid crystal display devices according to Examples 1 to 7;
FIG. 27 is a diagram showing manufacturing process examples of active matrix liquid crystal display devices according to Examples 1 to 7;
FIG. 28 is a diagram showing manufacturing process examples of active matrix liquid crystal display devices according to Examples 1 to 7;
FIG. 29 is a diagram illustrating an example of a manufacturing process of an active matrix liquid crystal display device according to Examples 1 to 7.
30 is a diagram showing manufacturing process examples of active matrix liquid crystal display devices according to Embodiments 1 to 7. FIG.
FIG. 31 is a view showing a manufacturing example of a light-emitting device according to Examples 1 to 7;
32 is a diagram showing an example of manufacturing a light-emitting device according to Examples 1 to 7. FIG.
FIG. 33 is a view showing a manufacturing example of a light emitting device according to Examples 1 to 7;
34 is a diagram showing an example of manufacturing light emitting devices according to Examples 1 to 7. FIG.
FIG. 35 is a view showing a manufacturing example of a light-emitting device according to Examples 1 to 7;
FIG. 36 is a diagram showing a manufacturing example of a light emitting device according to Examples 1 to 7;
FIG. 37 is a diagram illustrating an example of an image display device.
FIG. 38 is a diagram illustrating an example of an image display device.
FIG. 39 is a diagram showing a configuration of a projection type liquid crystal display device.
FIG. 40 is a schematic view of an active matrix liquid crystal display device.
FIG. 41 is a schematic diagram of a conventional digital source signal line drive circuit.
FIG. 42 is a schematic diagram of a source signal line drive circuit that drives four source signal lines with one D / A conversion circuit.
FIG. 43 is a schematic diagram of a source signal line drive circuit in which the grayscale power supply lines are connected to the D / A conversion circuit according to FIG. 41 and four source signal lines are driven by one D / A conversion circuit. It is.
[Explanation of symbols]
100 gradation power line connection selector switch
101 Source signal line drive circuit
102 Gate signal line driving circuit
103 Pixel array section
104 Each source signal line
105 Each gate signal line
106 TFT as a switching element of each pixel
201 Shift register
202 Basic circuit of shift register
203 latch 1 circuit
204 Latch 2 circuit
205 D / A conversion circuit
301 Parallel / serial conversion circuit
302 Source line selection circuit

Claims (11)

An image having a source signal line driver circuit, a gate signal line driver circuit, a pixel electrode in each region where the plurality of source signal lines and the plurality of gate signal lines intersect, and a switching element for driving the pixel electrode In the display device,
In the source signal line drive circuit, a D / A conversion circuit that converts a digital video signal into an analog video signal, and a source line selection circuit,
The D / A conversion circuit is provided for each of three or more source signal lines among the plurality of source signal lines,
In synchronization with the timing at which the digital video signal is input to each D / A conversion circuit, each source line selection circuit selects a source signal line corresponding to the digital video signal among the plurality of source signal lines, It writes the analog video signal output from the respective D / a conversion circuit to the selected source signal line,
Two gradation power supply lines each consisting of a plurality of lines, and a connection changeover switch that connects any one of the two gradation power supply lines to each of the D / A conversion circuits,
The period during which each source line selection circuit selects an odd-numbered source signal line during one horizontal writing period according to a control signal input to the connection changeover switch is the first of the two systems of gradation power supply lines. A period of gradation power supply line is connected to each of the D / A conversion circuits, and during the period in which each of the source line selection circuits selects an even-numbered source signal line, a gradation power supply line of a system different from the first is connected. Connected to each D / A converter circuit ;
An image display apparatus, wherein each of the source line selection circuits continuously selects either the odd-numbered or even-numbered source signal line within a certain period of one horizontal writing period. An image having a source signal line driver circuit, a gate signal line driver circuit, a pixel electrode in each region where the plurality of source signal lines and the plurality of gate signal lines intersect, and a switching element for driving the pixel electrode In the display device,
In the source signal line drive circuit, a D / A conversion circuit that converts a digital video signal into an analog video signal, and a source line selection circuit,
The D / A conversion circuit is provided for each of three or more source signal lines among the plurality of source signal lines,
In synchronization with the timing at which the digital video signal is input to each D / A conversion circuit, each source line selection circuit selects a source signal line corresponding to the digital video signal among the plurality of source signal lines, It writes the analog video signal output from the respective D / a conversion circuit to the selected source signal line,
One gray scale power supply line consisting of a plurality of lines is connected to each D / A conversion circuit, and the power supply voltage of each gray scale power supply line undergoes polarity inversion during one horizontal writing period,
A voltage having a different polarity is applied to each gradation power line in a period in which each source line selection circuit selects an odd-numbered source signal line and a period in which an even-numbered source signal line is selected ,
An image display apparatus, wherein each of the source line selection circuits continuously selects either the odd-numbered or even-numbered source signal line within a certain period of one horizontal writing period. A D / A conversion circuit, a first circuit, and a second circuit;
The D / A conversion circuit is provided for every N (N is a natural number of 3 or more) source signal lines,
The D / A conversion circuit has a function of converting a digital video signal into an analog video signal,
The first circuit has a function of selecting a source signal line corresponding to the digital video signal among the N source signal lines,
The second circuit has a function of connecting one of a plurality of first wirings and a plurality of second wirings to the D / A conversion circuit,
The plurality of first wirings are supplied with a plurality of first voltages for setting the analog video signal to a first polarity,
The plurality of second wirings are supplied with a plurality of second voltages for setting the analog video signal to a second polarity,
The image display apparatus according to claim 1, wherein odd-numbered or even-numbered source signal lines among the N source signal lines are continuously selected by the first circuit. A D / A conversion circuit, a first circuit, and a second circuit;
The D / A conversion circuit is provided for every N (N is a natural number of 3 or more) source signal lines,
The D / A conversion circuit has a function of converting a digital video signal into an analog video signal,
The first circuit has a function of selecting a source signal line corresponding to the digital video signal among the N source signal lines,
The second circuit connects a plurality of first wirings to the D / A conversion circuit when the odd-numbered source signal line among the N source signal lines is selected, and the N circuit When an even-numbered source signal line is selected among the two source signal lines, the plurality of second wirings have a function of connecting to the D / A conversion circuit,
The plurality of first wirings are supplied with a plurality of first voltages for setting the analog video signal to a first polarity,
The plurality of second wirings are supplied with a plurality of second voltages for setting the analog video signal to a second polarity,
The image display apparatus according to claim 1, wherein odd-numbered or even-numbered source signal lines among the N source signal lines are continuously selected by the first circuit. A D / A conversion circuit and a first circuit;
The D / A conversion circuit is provided for every N (N is a natural number of 3 or more) source signal lines,
The D / A conversion circuit has a function of converting a digital video signal into an analog video signal,
The first circuit has a function of selecting a source signal line corresponding to the digital video signal among the N source signal lines,
The D / A conversion circuit is connected to a plurality of wirings,
The plurality of wirings are supplied with a plurality of first voltages for setting the analog video signal to a first polarity or a plurality of second voltages for setting the analog video signal to a second polarity. ,
The image display apparatus according to claim 1, wherein odd-numbered or even-numbered source signal lines among the N source signal lines are continuously selected by the first circuit. In any one of Claims 1 to 5 ,
An image display device using a liquid crystal material for a display element. In any one of Claims 1 to 5 ,
An image display device using a light emitting material for a display element. A mobile phone , a video camera, a personal computer, a head-mounted display, a television, a portable book, a DVD player, a digital camera, or the like having the image display device according to any one of claims 1 to 7. Projector . An electronic apparatus, comprising the image display apparatus according to any one of claims 1 to 7. An image having a source signal line driver circuit, a gate signal line driver circuit, a pixel electrode in each region where the plurality of source signal lines and the plurality of gate signal lines intersect, and a switching element for driving the pixel electrode In the display device,
In the source signal line drive circuit, a D / A conversion circuit that converts a digital video signal into an analog video signal, and a source line selection circuit,
The D / A conversion circuit is provided for each of three or more source signal lines among the plurality of source signal lines,
In synchronization with the timing at which the digital video signal is input to each D / A conversion circuit, each source line selection circuit selects a source signal line corresponding to the digital video signal among the plurality of source signal lines, It writes the analog video signal output from the respective D / a conversion circuit to the selected source signal line,
Two gradation power supply lines each consisting of a plurality of lines, and a connection changeover switch that connects any one of the two gradation power supply lines to each of the D / A conversion circuits,
The period during which each source line selection circuit selects an odd-numbered source signal line during one horizontal writing period according to a control signal input to the connection changeover switch is the first of the two systems of gradation power supply lines. A period of gradation power supply line is connected to each of the D / A conversion circuits, and during the period in which each of the source line selection circuits selects an even-numbered source signal line, a gradation power supply line of a system different from the first is connected. Connected to each D / A converter circuit ;
A driving method of an image display device, wherein each of the source line selection circuits continuously selects either the odd-numbered or even-numbered source signal line within a certain period of one horizontal writing period. An image having a source signal line driver circuit, a gate signal line driver circuit, a pixel electrode in each region where the plurality of source signal lines and the plurality of gate signal lines intersect, and a switching element for driving the pixel electrode In the display device,
In the source signal line drive circuit, a D / A conversion circuit that converts a digital video signal into an analog video signal, and a source line selection circuit,
The D / A conversion circuit is provided for each of three or more source signal lines among the plurality of source signal lines,
In synchronization with the timing at which the digital video signal is input to each D / A conversion circuit, each source line selection circuit selects a source signal line corresponding to the digital video signal among the plurality of source signal lines, It writes the analog video signal output from the respective D / a conversion circuit to the selected source signal line,
One gray scale power supply line consisting of a plurality of lines is connected to each D / A conversion circuit, and the power supply voltage of each gray scale power supply line undergoes polarity inversion during one horizontal writing period,
A voltage having a different polarity is applied to each gradation power line in a period in which each source line selection circuit selects an odd-numbered source signal line and a period in which an even-numbered source signal line is selected ,
A driving method of an image display device, wherein each of the source line selection circuits continuously selects either the odd-numbered or even-numbered source signal line within a certain period of one horizontal writing period.

Images