JP2006317566A - Display device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify constitution of a circuit itself for executing gamma conversion. <P>SOLUTION: A liquid crystal panel 100 performs color display with a pixel 110 consisting of three subpixels 120 of R, G, and B. At the intersection between a scanning line 311 and a data line 211, the subpixel 120 is provided so that one color corresponds to one row of scanning line, and a so-called lateral stripe structure is made. When the scanning line is selected, each subpixel 120 has gradation according to the voltage of the corresponding data line. A characteristic changing part 500 sets a gamma characteristic corresponding to the color of the subpixel subjected to horizontal scanning to a gamma conversion circuit 252. The gamma conversion circuit 252, supplied in synchronization with vertical scanning and the horizontal scanning of the liquid crystal panel 100, converts gradation data Da prescribing the gradation of the subpixels into subpixel data Db prescribing the voltage corresponding to the gradation, using the gamma characteristic set by the characteristic changing part 500. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for reducing the cost and power consumption by simplifying the configuration.

It is generally known that human visual characteristics have logarithmic or exponential properties. For this reason, even if the gradation changes linearly, the human eye may not feel that it changes linearly. Further, in a display device that performs display by electro-optic change such as liquid crystal or organic EL (Electronic Luminescence), even if the voltage or current changes linearly, the gradation is curved.
For this reason, in display devices, digital data that linearly defines the gradation of sub-pixels is converted into curvilinear characteristics (γ characteristics) in consideration of the luminance of the display elements and human visual characteristics. In many cases, gradations are expressed in accordance with the obtained characteristics so that gradation changes appear linearly when viewed by human eyes (see, for example, Patent Document 1). Such a series of processes may be referred to as γ conversion.
Japanese Patent Laid-Open No. 2004-70367

By the way, for example, when color display is performed with three primary colors of R (red), G (green), and B (blue), the γ characteristics of the respective colors are different, so that γ conversion is required for each of RGB. For this reason, in the configuration in which any one of RGB sub-pixels is associated with the data line of each column, it is necessary to prepare three sets for each color for the characteristics of converting digital data into voltage (or current). It became complicated.
The present invention has been made in view of such circumstances, and an object of the present invention is to display a circuit that performs γ conversion by using a smaller number than the number of primary colors to simplify the configuration. It is to provide an apparatus and an electronic device.

In order to achieve the above-described object, the present invention provides 1 by m (m is an integer of 3 or more) color sub-pixels.
One pixel is displayed, and the sub-pixel has an n color (n is an integer satisfying m>n> 0) corresponding to one scanning line at the intersection of the plurality of scanning lines and the plurality of data lines. And a scanning device that has a gradation corresponding to the voltage or current of the corresponding data line when the scanning line is selected, and that selects the plurality of scanning lines in a predetermined order. The gradation data specifying the gradation of the sub-pixel of the driving circuit and the selected scanning line is converted into a voltage or current data signal corresponding to the voltage or current characteristic for the gradation for each color of the sub-pixel. And a data line driving circuit for supplying to the data line. According to this configuration, gradation data can be converted into a voltage or current data signal by n circuits smaller than m, which can contribute to simplification of the configuration.

Here, in the present invention, the sub-pixel includes a pixel electrode and a three-terminal switching element that becomes conductive between the data line and the pixel electrode when a corresponding scanning line is selected. In addition, it is preferable that the gradation is in accordance with the voltage or current of the pixel electrode.
In this configuration, the circuit further includes a characteristic change circuit and a conversion circuit, and the characteristic change circuit corresponds to the color of the sub-pixel of the selected scanning line among the voltage or current characteristics with respect to a predetermined gradation. A voltage or current characteristic with respect to a gradation is set in the conversion circuit, and the conversion circuit converts the gradation data into a sub-voltage indicating current or voltage according to the voltage or current characteristic with respect to the gradation set by the characteristic changing circuit. It is preferable that the data line driver circuit generates a data signal based on the sub-pixel data by converting into pixel data.
In the present invention, the sub-pixel has a series connection of a capacitor, a pixel electrode, and a two-terminal switching element that becomes conductive when a corresponding scanning line is selected and a predetermined selection voltage is applied. A configuration in which the gradation is in accordance with the effective voltage value held in the capacitor, which is interposed between the corresponding scanning line and the data line, is also preferable.
In this configuration, it further includes a pulse interval setting circuit and a pulse generation circuit, wherein the scanning line driving circuit applies a selection voltage for bringing the switching element into a conductive state to the selected scanning line, and the pulse interval setting circuit Sets an interval of a pulse signal that defines a voltage switching timing of a data signal for each gradation during a period in which the selection voltage is applied to the pulse generation circuit according to a color of a sub-pixel of a selected scanning line. The pulse generation circuit outputs the pulse signal at an interval set by the pulse generation circuit, and the data line driving circuit has a switching timing corresponding to the gradation specified by the gradation data, It is preferable that the voltage of the data signal is switched.
In the present invention, when m is 3 and n is 2, the three color sub-pixels are red, green and blue, and the red and green sub-pixels correspond to one scanning line and the other A blue sub-pixel is associated with a scanning line, the one pixel is associated with two columns of data lines, one column of data lines is connected to a red sub-pixel, and the other column of data lines is green A configuration may also be adopted in which the blue sub-pixels are also connected.
The present invention can also be conceptualized as an electronic apparatus having the electro-optical device.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the electro-optical device according to the first embodiment of the invention.
As shown in this figure, the electro-optical device 10 includes a liquid crystal panel 100, a data line driving circuit 250, a scanning line driving circuit 350, a control circuit 400, and a characteristic changing circuit 500.
Among these, in the liquid crystal panel 100, the scanning line 311 corresponds to each of RGB, and 32
While 0 × 3 rows extend in the row (X) direction, 240 data lines 211 are arranged in columns (Y
) Extending in the direction.

In the present embodiment, the sub-pixel 120 corresponds to any color of R (red), G (green), and B (blue), and corresponds to the intersection of the scanning line 311 and the data line 211, Each is arranged. The sub-pixels 120 are arranged in the row direction, and are so-called horizontal stripes that are repeatedly arranged as RGBRGB when viewed from the top to the bottom in the column direction. And RG
In this configuration, one pixel 110 is configured with the three colors B and displayed in color. Therefore, in this embodiment, the pixels 110 are arranged in a matrix of 320 vertical rows × 240 horizontal columns. However, the present invention is not intended to be limited to this arrangement.
The configuration of the liquid crystal panel 100 is not particularly shown, but the element substrate on which the scanning lines and the data lines are formed and the counter substrate on which the common electrode and the color filter are formed are bonded together with a sealing material with a certain gap. In addition, the liquid crystal is sealed in the gap.

A detailed configuration of the sub-pixel 120 will be described. FIG. 2 is a diagram showing an electrical configuration of the sub-pixel 120, and 1 corresponding to the intersection of i rows, j columns, and (j + 1) columns adjacent thereto.
A configuration for a total of two pixels of x2 is shown.
Here, i and (i + 1) are symbols for generally indicating a row in which the pixels 110 are arranged, and are integers of 1 to 320, and j and (j + 1) are columns in which the pixels 110 are arranged. In general, the symbol is an integer of 1 to 240.
In terms of the sub-pixel 120 instead of the pixel 110, for example, the R, G, and B sub-pixels 120 constituting the pixel 110 in the i-th row and j-th column are the (3i-2) th row and the (3i-1) th row. It can be said that the scanning lines 311 in the 3rd row and the 3ith row are provided in correspondence with the data line 211 in the jth column.

Since each of the sub-pixels 120 has the same electrical equivalent circuit, the R sub-pixel 120 in the pixel 110 in the i row and j column will be described as a representative.
, The source of an n-channel TFT (thin film transistor) 116 is connected to the data line 211 of the j-th column, and the drain thereof is connected to the pixel electrode (sub-pixel electrode) 118, while the gate is (3i -2) Connected to the scanning line 311 in the row.
These scanning line 311, data line 211, TFT 116 and pixel electrode 118 are all formed on the element substrate. On the other hand, the common electrode 108 is provided in common to all the sub-pixels so as to face the pixel electrode 118 formed on the element substrate. These pixel electrodes 1
A liquid crystal 105 is sandwiched between 18 and the common electrode 108. For this reason, for each sub-pixel,
A pixel capacitor (sub-pixel capacitor) including the pixel electrode 118, the common electrode 108, and the liquid crystal 105 is formed. In addition, although the voltage LCcom is applied to the common electrode 108,
For simplification of explanation, it is assumed to be equal to the amplitude center voltage Vc described later.
Here, when the scanning line 311 becomes H level by selection, the source and drain of the TFT 116 become conductive (on), so that the data signal supplied to the data line 211 is applied to the pixel electrode 118 while the selection is made. And the scanning line 311 becomes L level, and the TFT 11
Even when 6 is turned off, the voltage applied to the pixel electrode 118 is held by the pixel capacitance.

Although not shown in particular, the opposing surfaces of both substrates are respectively provided with alignment films that have been rubbed so that the major axis direction of the liquid crystal molecules is continuously twisted between the substrates by, for example, about 90 degrees. A polarizer corresponding to the orientation direction is provided on each back side of the substrate.
If the effective voltage applied to the pixel capacitor is zero, the light passing between the pixel electrode 118 and the common electrode 108 rotates about 90 degrees along the twist of the liquid crystal molecules, while the effective voltage value is As it increases, the liquid crystal molecules tilt in the direction of the electric field, and as a result, their optical rotation disappears. For this reason, for example, in a transmission type, a polarizer having a polarization axis aligned with the alignment direction on the incident side is arranged on the incident side, while a polarization having a polarization axis in a direction orthogonal to the alignment direction on the emission side is arranged on the output side. When a child is arranged, if the voltage effective value is close to zero, the light transmittance is minimized, while the amount of light transmitted increases as the voltage effective value increases, and finally the transmittance is maximized ( Normally black mode).

Further, in order to reduce the influence of charge leakage from the pixel capacitance via the TFT 116 at the time of OFF, the storage capacitor 109 is formed for each sub-pixel. One end of the storage capacitor 109 is connected to the pixel electrode 118 (the drain of the TFT 116), and the other end is commonly connected to the capacitor line 107 over all subpixels. Although not shown in FIG. 1, the capacitor line 107 is maintained at a constant temporal potential, for example, the same voltage LCcom as the common electrode 108.

Returning to FIG. 1 again, the control circuit 400 determines that one horizontal scanning period from the dot clock signal Dclk, the vertical scanning signal Vs, and the horizontal scanning signal Hs supplied from the host device (not shown). The liquid crystal panel 100 is scanned by various control signals such as a latch pulse LP (see FIG. 4) that defines the start time of the signal, a polarity instruction signal POL, a start pulse DY that defines the start time of the vertical scanning period (1F), and the clock signal CLY. And a selection signal Sel is supplied to the characteristic changing circuit 500.
Here, the polarity instruction signal POL is a signal for designating positive polarity writing when it is at the H level, and for designating negative polarity writing when it is at the L level. As shown in FIG. (1F)
In this case, the polarity is inverted every horizontal scanning period (1H) and the adjacent vertical scanning period (1
From the viewpoint of F), the entire waveforms are in a logically inverted relationship. The reason for polarity inversion is to prevent deterioration due to application of a direct current component to the liquid crystal 105.

As shown in FIG. 3, the scanning line driving circuit 350 sequentially takes and shifts the start pulse DY at the rising edge of the clock signal CLY, and uses the shift signal as a scanning signal for 320 × 3 scanning lines 311. To supply each. For this reason, one cycle of the clock signal CLY corresponds to a horizontal scanning period in which one scanning line 311 is selected.
Here, three rows of RGB corresponding to the pixels 110 in the i-th row, that is, the (3i-2) -th row,
The scanning signals supplied to the (3i-1) -th and 3i-th scanning lines 311 are denoted as Yi-R, Yi-G, and Yi-B, respectively.

The data line driver circuit 250 includes a γ conversion circuit 252 and a data signal supply circuit 254. Among them, the γ conversion circuit 252 is supplied from the host device in synchronization with the dot clock signal Dclk, the vertical scanning signal Vs, and the horizontal scanning signal Hs, and also defines, for example, a 6-bit gradation that defines the gradation of the subpixel. The data Da is γ-converted and output as, for example, 10-bit sub-pixel data Db indicating a voltage, which is specifically a conversion table.
The gradation data Da corresponds to each color, and in the present embodiment, the gradation of the sub-pixel is specified linearly. For this reason, if the gradation data Da is 6 bits, the gradation value of each color of RGB is designated in 64 steps from decimal values “0” to “63”.
When viewed with one pixel 110, about 260,000 colors (= 64 ³ ) can be displayed.
Here, the 6-bit gradation data Da is a decimal value “0” (a binary value “000000”).
The darkest gradation is specified when the value is, the gradation is specified so that it gradually becomes brighter as the decimal value increases, and the decimal value is “63” (the binary value is “111111”). In this case, the brightest gradation is designated.

In the present embodiment, since the stripe is a horizontal stripe, the gradation data Da corresponding to one row of pixels is divided into R, G, and B, and supplied for one color over one horizontal scanning period. It will be.
In the present embodiment, so-called line-sequential writing is performed, so that gradation data of sub-pixels positioned on the scanning line is supplied before the horizontal scanning period for selecting one scanning line. Therefore, for example, as shown in FIG. 3, in a period in which the second row scanning line 311 corresponding to G of the first row pixel is selected (a period in which the scanning signal Yi-G is at the H level), Gradation data Da of the G sub-pixel 120 in the third row corresponding to B of the pixel in the first row selected immediately after that is supplied from the first column to the 240th column is sequentially supplied from the host device. The

The data signal supply circuit 254 includes sub pixel data D converted by the γ conversion circuit 252.
In the horizontal scanning period in which b is latched for one row and the corresponding scanning line 311 is selected, if positive polarity writing is specified, it is specified by the latched subpixel data Db. While a voltage higher than the voltage Vc is generated by the voltage, if negative polarity writing is specified, a voltage lower than the voltage Vc is generated by the voltage specified by the latched sub-pixel data Db. Are supplied to the corresponding data line 211. The data signal supply circuit 254 executes such an operation for all the data lines 211 in the 1st to 240th columns.
FIG. 4 shows an example of the voltage waveform of the data signal supplied to the data line 211 in the j-th column for convenience, denoted as Xj.

By the way, the gradation data Da supplied from the host device linearly defines the gradation of the subpixel 120, whereas the subpixel data Db defines the voltage of the data signal. In other words, since the voltage of the data signal is applied to the pixel electrode 118 in the sub-pixel 120 to define the effective voltage value of the pixel capacitance, the sub-pixel data Db defines the effective voltage value of the pixel capacitance. .
As described above, even if the voltage changes linearly, the gradation expressed by the sub-pixel 120 changes in a curved manner. Specifically, the RGB voltage (effective voltage value of the pixel capacitance) -transmittance characteristic is
It changes as shown in FIG.
As shown in this figure, with respect to the characteristics of R, the transmittance is almost zero from the voltage zero to the voltage Vmin, and when the voltage Vmin is exceeded, the transmittance increases as the voltage increases, and reaches the voltage VRmax. Then, the transmittance is almost 100%.

Here, in the present embodiment, the voltage LCcom of the common electrode 108 is equal to the voltage Vc that is a reference for polarity, and therefore the horizontal axis voltage in FIG. 5 should be specified by the differential voltage with respect to the voltage Vc, that is, the sub-pixel data Db. Will show the voltage. For this reason, the γ conversion circuit 252 has R
When converting the gradation data Da for R into the sub-pixel data Db for R, FIG.
As shown in FIG. 5, when the gradation data Da is a decimal value “0” (binary value “000000”), the sub-pixel data Db specifies the voltage Vmin, and the gradation data Da is a decimal value. "6"
3 ”(“ 111111 ”in binary value), the subpixel data Db is the voltage VRmax.
When the intermediate gradation is designated by the gradation data Da, the subpixel data Db designates a voltage that changes the gradation linearly according to human visual characteristics. It becomes.
As shown in this figure, for the characteristics of G and B, from voltage zero to voltage Vmin,
The transmittance is almost zero. When the voltage exceeds Vmin, the transmittance increases as the voltage increases. When the voltage reaches VGmax and VBmax, the transmittance becomes almost 100%.
However, when the gradation data Da for G and B is converted into the sub-pixel data Db for G and B, the gradation data Da is binary value “000000” as shown in FIG. In some cases, the sub-pixel data Db specifies the voltage Vmin, and the gradation data Da is a binary value “1111”.
In the case of 11 ″, the subpixel data Db designates the voltage VGmax for G, the subpixel data Db designates the voltage VBmax for B, and the intermediate gradation is designated for B.
The sub-pixel data Db designates a voltage that changes the gradation linearly according to human visual characteristics.

As described above, the γ conversion circuit 252 needs to convert the gradation data Da into the sub-pixel data Db with different characteristics for each RGB color. However, in the present embodiment, one row of scanning lines 3
11 is selected, the color of the sub-pixel 120 located in the selected scanning line is RG
Any one of B colors. That is, in the present embodiment, the characteristics of the three colors are not used at the same time in the one horizontal scanning period, and the sub-pixels 12 positioned on the selected scanning line 311 are used.
Only the properties corresponding to the 0 color are used.
Therefore, in the present embodiment, the characteristic changing circuit 500 changes the γ characteristic of the γ conversion circuit 252 to 1
In the order of RGBRGB for each horizontal scanning period, the color is changed so as to correspond to the color of the sub-pixel 120 of the scanning line to be selected (strictly, the color of the gradation data Da supplied from the host device). Specifically, as shown in FIG. 3, the characteristic changing circuit 500 changes the content of the conversion table in the γ conversion circuit 252 according to the color of the sub-pixel 120 one row before the selected scanning line. Rewrite every horizontal scanning period.

Since the control circuit 400 outputs the start pulse DY at the start of one vertical scanning period and outputs the latch pulse LP at the start of one horizontal scanning period, for example, the characteristic changing circuit 500 changes the internal count state. The color corresponding to the scanning line 311 selected at the present time is determined by resetting with the start pulse DY and the state transition with the latch pulse LP in the order of 0 → 1 → 2 → 0 → 1 → 2. be able to.
As described above, the scanning line 311 one row before the scanning line 311 selected at the present time.
Since the gradation data Da corresponding to is supplied from the host device, the characteristic changing circuit 500 determines that the color corresponding to the selected scanning line 311 is, for example, R, for example, in the previous row. The γ characteristic of the color B corresponding to the scanning line 311 is set in the γ conversion circuit 252.
As a result, the γ characteristic of the same color as that of the gradation data Da supplied from the host device is set in the γ conversion circuit 252, so that the gradation data Da is converted with the γ characteristic of the corresponding color and sub- The pixel data Db is latched by the data signal supply circuit 254.
Here, the sub-pixel data Db latched corresponding to the sub-pixel 120 in the j-th column has the polarity specified by the polarity instruction signal POL in one horizontal scanning period selected by the corresponding scanning line 311. It is converted into a data signal Xj having a voltage specified by the sub-pixel data Db, and supplied to the data line 211 in the j-th column. Such an operation is simultaneously executed over the 1st to 240th columns.

According to the first embodiment, the γ conversion circuit 252 needs to perform γ conversion corresponding to the three colors of RGB, but does not convert the three colors of RGB at the same time, and one horizontal scanning period (1H )
Since each RGB color is converted in turn, the capacity required for the conversion table is one color.
Furthermore, the D / A conversion characteristics for converting the sub-pixel data into data signals need not be distinguished for each RGB, and are aligned with the same characteristics for each column.
For this reason, in the present embodiment, the configuration can be simplified, and power consumption can be reduced accordingly.

In the first embodiment, the voltage LCcom, although it is ideal to match with the voltage V _C which is the reference of the writing polarity, the TFT 116, due to the parasitic capacitance between the gate and the drain, on Causes a phenomenon in which the potential of the drain (pixel electrode 118) decreases when the switch is turned off (referred to as push-down, penetration, field-through, etc.). In order to prevent the deterioration of the liquid crystal, AC driving is basically used for the pixel capacitance, so that the common electrode 108 is alternately written on the higher side (positive polarity) and the lower side (negative polarity) as described above. , in a state of being matched voltage LCcom the voltage V _C, when the alternating writing, for pushdown, the effective voltage value of the pixel capacitance, who negative writing becomes larger than the positive polarity writing . For this reason, when positive polarity / negative polarity writing is performed at the same gradation, the voltage LCcom of the common electrode 108 is set to the amplitude reference of the data signal so that the effective voltage value of the pixel capacitance is equal to each other in each writing polarity. it is desirable to set a little lower than the voltage V _C is.

Next, an electro-optical device according to a second embodiment of the invention will be described. FIG. 7 is a block diagram illustrating an overall configuration of the electro-optical device 10 according to the second embodiment, and FIG. 8 is a diagram illustrating an equivalent circuit of the sub-pixel 120 according to the second embodiment.
In the first embodiment, the pixel electrode 118 is switched by the TFT 116 that is a three-terminal switching element. However, in the second embodiment, the pixel electrode 118 is switched by a TFD (thin film diode) that is a two-terminal switching element. It is a configuration. For this reason, the scanning signal waveform to the scanning line 311 and the data signal waveform to the data line 211 are different from the first embodiment. As will be described in detail later, a selection voltage is applied to the scanning line 311 as a scanning signal in the latter half of the selected horizontal scanning period, while the data line 21
1, a data signal having a polarity opposite to that of the selection voltage and having a pulse width corresponding to the gradation is applied, and the pixel capacitor holds a voltage defined by the selection voltage and the pulse width. It becomes the composition which is done.
As described above, the γ characteristic differs for each RGB, but in this second embodiment, the pulse width corresponding to the gradation is changed, so that the relationship between the gradation and the pulse width is switched for each RGB.

First, the configuration of the sub-pixel 120 in the second embodiment will be described.
As shown in FIG. 8, the sub-pixel 120 is provided corresponding to the intersection of the scanning line 311 and the data line 211 as in the first embodiment, but one end of the TFD 220 is connected to the data line 211. On the other hand, the other end of the TFD 220 is connected to the pixel electrode 118 constituting the pixel capacitor, and the other end of the pixel capacitor is connected to the scanning line 311, which is different from the first embodiment.
Note that the serial connection of the TFD 220 and the pixel capacitor may be reversed so that one end of the TFD 220 is connected to the scanning line 311 and the other end of the pixel capacitor is connected to the data line 211.

Here, as well known, the TFD 220 has a conductor / insulator / conductor sandwich structure and has a diode switching characteristic in which the current-voltage characteristic is nonlinear in both positive and negative directions. .
Therefore, when the scanning line 311 is selected and a selection voltage is applied, the TFD 220 corresponding to the intersection of the scanning line 311 and the data line 211 is forcibly set regardless of the voltage applied to the data line 211. A voltage corresponding to the difference between the selection voltage and the data voltage is held in the pixel capacitor connected to the TFD 220 that is turned on and turned on. When the selection of the scanning line 311 is completed and a non-selection voltage is applied, the TFD 220 is turned off.
The voltage holding state in the pixel capacitance is maintained. In the pixel capacitance, the alignment state of the liquid crystal 105 changes according to the holding voltage, and the amount of light passing through the polarizer (not shown) changes according to the voltage effective value. Therefore, data when the selection voltage is applied The effective voltage value held in the pixel capacitance is controlled for each sub-pixel according to the pulse width of the signal, thereby enabling a predetermined gradation display.

The scanning line driving circuit 352 according to the second embodiment selects 320 × 3 rows of scanning lines 311 one by one for each horizontal scanning period (1H), and for the selected scanning line, the horizontal scanning period. While the selection voltage is applied in the second half period (1 / 2H), for the other scanning lines,
Each non-selection voltage is supplied.
Specifically, as shown in FIG. 9, the scanning line driving circuit 352 generates a start pulse DY that is supplied at the beginning of the vertical scanning period (1F) with a period of one horizontal scanning period (1H) and a duty cycle. The scanning line 311 is sequentially selected and shifted at the rising edge of the clock signal CLY having a ratio of 50%, and the scanning signal 311 is selected in order, and the clock signal CLY becomes L level during these selection periods (one horizontal scanning period). Define the second half of one horizontal scan period according to the period,
The following voltage is selected and applied.
In other words, the scanning line driver circuit 352 has a certain scanning line 311 in one horizontal scanning period.
Selecting, in the latter half period of one horizontal scanning period selected (1 / 2H), if the polarity indicating signal POL is at the H level, selects the positive polarity selection voltage + V _S, when the selection is completed, the selection voltage select positive polarity non-selection voltage + V _d corresponding to, the scanning line 3 a selected voltage
11, while the polarity instruction signal POL is at the L level in the latter half period (1 / 2H) of the selected one horizontal scanning period, the negative selection voltage −V _S is selected, and the selection ends. Then, the negative non-selection voltage −V _d corresponding to the selection voltage is selected, and the selected voltage is applied to the scanning line 311.
Therefore, in the second embodiment, unlike the first embodiment in which the selection of the scanning line 311 coincides with the selection voltage application period, the selection of the scanning line 311 is one horizontal scanning period.
The selection voltage application period 11 is the latter half of one horizontal scanning period.

Next, the voltage waveform of the scanning signal by the scanning line driving circuit 352 will be described with reference to FIG. When the scanning line 311 corresponding to R of the pixel in the first row is selected, the scanning signal Y1-R corresponding to the scanning line is supplied with the polarity instruction signal POL in the latter half period (1 / 2H) of the horizontal scanning period. Corresponding to the H level, the positive selection voltage + V _S and then the positive non-selection voltage + V _d . When one vertical scanning period (1F) has passed and the selection is made again, the scanning signal Y1-R becomes The negative selection voltage −V _S and then the negative non-selection voltage −V _d , and this cycle is repeated thereafter.
Further, since the logic level of the polarity instruction signal POL is inverted every horizontal scanning period (1H) as in the first embodiment, the scanning signal supplied to each scanning line 311 is one horizontal scanning period (1H).
), That is, the polarity is alternately inverted every row of the scanning line 311. For example, in a certain frame, if the selection voltage of the scanning signal Y1-R is the positive selection voltage + V _S , 1
After lapse of a horizontal scanning period, the selection voltage of the scanning signal Y1-G corresponding to the next line is the negative selection voltage -V _S.

Next, the data line driving circuit 260 in FIG. 1 will be described. Data line driving circuit 26
0 supplies the data signals X1, X2, X3,..., X240 via the data lines 211 in the first, second, third,.
Here, the control signals used in the data line driving circuit 260 in the second embodiment will be described.
First, as shown in FIG. 10, the reset signal RES is generated during one horizontal scanning period (1H).
These pulses are output at the beginning of the first half period and at the beginning of the second half period, respectively. First, the AC drive signal MX is a signal for AC driving the sub-pixel 120, and as shown in the figure, the phase is advanced by 90 degrees from the polarity instruction signal POL. Therefore, the AC drive signal MX becomes H level in the first half period and L level in the second half period in one horizontal scanning period (1H) in which the positive voltage + V _S is designated as the selection voltage. In one horizontal scanning period (1H) in which the negative voltage −V _S is specified as the voltage, the voltage is at the L level in the first half period and is at the H level in the second half period. The reset signal RES and the AC drive signal MX are supplied from the control circuit 400 to the data line drive circuit 260 together with the latch pulse LP.

Third, the gradation code pulse GCP is generated by the GCP generation circuit 600 in FIG. 7, and, as shown in FIG. 10, the highest order in decimal notation in each of the first half period and the second half period of one horizontal scanning period. Intermediate gradation value “6” excluding tone value “63” and lowest gradation value “0”
2 ”to“ 1 ”and gradation values“ 62 ”,“ 61 ”,“ 60 ”,...,“ 2 ”,
The pulses are arranged in the order of “1” and define the voltage switching timing of the data signal for each intermediate gradation.
In FIG. 10, only one type of gradation code pulse GCP is shown, but actually, in the GCP generation circuit 600, three types of RGB are prepared and selected scanning lines 3 are selected.
11 corresponding to the color corresponding to 11 is output. In FIG. 10, the gradation code pulse G
Although CPs appear to be output at equal intervals, in reality, they are output at unequal intervals in accordance with the γ characteristics, as will be described later.
The latch pulse LP is a pulse supplied at the start of the horizontal scanning period, as in the first embodiment.

On the other hand, in the second embodiment, the gradation data Da is directly supplied from the host device to the data line driving circuit 260. The data line driving circuit 260 converts the gradation data Da of the sub-pixel 120 located on the selected scanning line 311 into a data signal having a pulse width corresponding to the gradation value as follows. To the data line 211 to be processed. This operation is performed by the data line driving circuit 2
60 is executed for each of the 240 columns located on the selected scan line 311.
In the present embodiment, the data signals X1, X2, X3, ..., X240 includes a voltage + _{V d} corresponding to the H level of the AC drive signal MX, a voltage -V _d corresponding to the L level of the AC drive signal MX One of the two values is taken.

Here, regarding the voltage regulating operation of the data signal Xj in the j-th column of the data line driving circuit 260, in one horizontal scanning period (1H) in which the polarity instruction signal POL is at the H level, j
If the gradation specified by the gradation data Da in the column is an intermediate gradation other than the highest value “63” and the lowest value “0”, first, the first half period (1 / 2H) of one horizontal scanning period The voltage is reset to a voltage corresponding to a level opposite to the level of the AC drive signal MX by the reset signal RES supplied first, and secondly, of the gradation code pulse GCP, the one corresponding to the gradation data Da. At the rising edge, the voltage corresponding to the same level as the AC drive signal MX is set, and thirdly, the reset signal RES supplied at the beginning of the second half period (1 / 2H) of one horizontal scanning period is ignored, 4. The voltage of the data signal Xj is defined so that the voltage corresponding to the same level as the AC drive signal MX is reset at the rising edge of the grayscale code pulse GCP corresponding to the grayscale data Da. You .
However, the data line driving circuit 260 is a level obtained by inverting the AC driving signal MX if the gradation data Da is “0” which is the lowest value in one horizontal scanning period (1H) in which the polarity instruction signal POL is at the H level. In addition, the gradation data Da is the maximum value “63”.
If so, the voltage of the data signal Xj is defined so that the voltage corresponds to the same level as the AC drive signal MX.
Further, the data line driving circuit 250 is configured such that, in one horizontal scanning period (1H) in which the polarity instruction signal POL is at L level, the voltage of the data signal is equal to one horizontal scanning period (1H) in which the polarity instruction signal POL is at H level. + _V d, replace the -V _d.

Therefore, the relationship between the waveform of the data signal and the gradation data Da is as shown in FIG. That is, when the positive selection voltage + V _S is applied to the selected scanning line in the second half of one horizontal scanning period, the gradation data Da corresponding to the j-th sub-pixel 120 located on the selected scanning line is As the subpixel is designated to be brighter, the data signal X
In j, the application period of the voltage −V _{d having} a polarity opposite to that of the selection voltage + V _S becomes longer, while when the negative selection voltage −V _S is applied to the selection scanning line, the gradation data Da is as specifies that brighter sub-pixels, the application period of the voltage + V _d of the opposite polarity is long with the selection voltage -V _S.
Note that, in the first half period of one horizontal scanning period, an inverted waveform of the applied waveform in the second half period is obtained. Therefore, in one horizontal scanning period viewed through the first half and the second half, the voltage + V _d
Period taking period and a voltage -V _d taking the display unevenness becomes 50/50 regardless gradation values specified by the gradation data Da, due to the voltage of the data signal is dominant in either Is suppressed.
In FIG. 10, the hatching of the data signal Xj is a period (pulse) in which a voltage having a polarity opposite to that of the selection voltage, that is, a voltage component that brightens the subpixel, is applied during a period in which the selection voltage is applied to the scanning line 311. Width). FIG. 10 shows only representative gradation values.

In the second embodiment, the effective voltage value held in the pixel capacitor is defined by the pulse width of the data signal in the second half period, which is the selection voltage application period, in one horizontal scanning period in which the scanning line 311 is selected. . The pulse width of the data signal is determined by the arrangement (output pitch) of the gradation code pulses GCP, and the gradation code pulses GCP are output by the GCP generation circuit 600.
Therefore, if the GCP generation circuit 600 changes the output pitch of the gradation code pulse GCP for each RGB, the γ characteristics can be made different for each RGB without converting the gradation data Da.
Note that the GCP generation circuit 600 can determine the color of the sub-pixel 120 corresponding to the selected scanning line 311 by the same method as the characteristic changing circuit 500 in the first embodiment. However, the characteristic changing circuit 500 in the first embodiment is different from the selected scanning line 311.
The GCP generation circuit 600 according to the second embodiment sets the gradation code pulse GCP corresponding to the color of the selected scanning line 311 while the γ characteristic corresponding to the color of the previous scanning line 311 is set. Is output.

As shown in FIG. 5, in order to obtain brightness corresponding to the same gradation for RGB, R
, G, and B in this order require a high voltage. Therefore, for the arrangement of the gradation code pulses GCP, for example, as shown in FIG. 11, a pulse corresponding to the same gradation is applied to each of the first half period and the second half period of one horizontal scanning period which is a reference of the pulse width. What is necessary is just to position so that it may become a time front in order of RGB from the terminal.
When specifying a dark gradation, since there is almost no voltage difference for each RGB color as shown in FIG. 5, a pulse corresponding to a low gradation value (eg, “1”) is almost the same in RGB. Located at the same point. In other words, as shown in FIG. 5, as the bright gradation is specified (as the gradation value increases), the voltage difference for achieving the same gradation increases, so the same gradation in RGB What is necessary is just to set so that the deviation | shift amount of the position of the pulse corresponding to a value may become large.

According to the second embodiment, the γ conversion circuit 252 as in the first embodiment is unnecessary, and the GCP
The generation circuit 600 only needs to change the output pitch of the gradation code pulse GCP in accordance with the RGB colors. Furthermore, since it is not necessary to change the data line drive circuit 260 significantly from the conventional configuration, according to the second embodiment, color display corrected by the γ characteristic for each RGB color is realized with a simpler configuration. It becomes possible.

In the first and second embodiments described above, the horizontal stripe configuration in which the pixels for one row correspond to the three scanning lines 311 and the RGB colors correspond to each row is used. Is not limited to this.
For example, as shown in FIG. 12, one row of pixels corresponds to “2” rows of scanning lines 311 that are less than the number of primary colors “3”, and one scanning line 311 has R and G. , B corresponding to the other scanning line 311, one pixel corresponding to two columns of data lines 211, one column data line 211 dedicated to R, and the other column data line 211
It is good also as a structure which uses both for GB.

Here, FIG. 13 shows a configuration for two pixels adjacent in the Y direction in this configuration, specifically i
It is an equivalent circuit showing the configuration of a pixel 110 in row j column and a pixel 110 in (i + 1) row j column.
Note that the pixel 110 in the i row and the j column first includes the scanning line 311 in the (2i-1) th row and (2
j−1) R sub-pixel 120 corresponding to the intersection with the data line 211 of the column, second, (2i
-1) G sub-pixel 120 corresponding to the intersection of the scanning line 311 in the row and the data line 211 in the 2j column, and thirdly, the scanning line 311 in the 2i row and the (2j-1) column The B sub-pixel 120 corresponding to the intersection with the data line 211 is formed.

In the configuration shown in FIG. 12, when the same pixel arrangement as that of the first or second embodiment is used, the total number of scanning lines 311 is 320 × 2 rows, and the total number of data lines 211 is 240 × 2 columns. . In FIG. 12, the control circuit 400 and control signals output from the control circuit 400 are not shown.
In this configuration, the scanning line driving circuit 354 outputs a scanning signal as shown in FIG. In this figure, the scanning signals supplied to the scanning lines 311 corresponding to the pixels 110 in the i-th row, specifically, the (2i-1) -th row and the 2i-th row are Yi-RG, And Yi-B, and the scanning lines 311 are arranged in order from the top in one horizontal scanning period (1H).
The points selected for each are the same as in the first and second embodiments.

As shown in FIG. 5, since the γ characteristics of GB are close to each other, the data line driving circuit 262 in FIG. 12 also uses the γ characteristics of GB. For this reason, the data line driving circuit 262 receives the supply of the gradation data Da directly from the host device, and converts the R gradation data into a voltage with the γ characteristic of R and supplies it to the R data line 211. The G and B gradation data supplied is converted into a voltage with a γ characteristic also used for GB and supplied to a data line 211 also used for GB.
In FIG. 12, the (2j−1) th column corresponding to the pixel 110 in the j-th row, and
The data signals supplied to the 2j-th column data line 211 are Xj-R and Xj, respectively.
-It is written as GB.

In such a configuration, when the arrangement of the pixels 110 is the same as in the first and second embodiments,
Since the number of scanning lines 311 can be reduced to 2/3, the vertical scanning frequency can be lowered.
Therefore, when the passive matrix is adopted instead of the active matrix, the drive duty ratio can be lowered. Furthermore, since the G pixel area with high visibility can be doubled, color reproducibility can be greatly improved.

In the first and second embodiments and the like described above, the polarity instruction signal POL is set to one horizontal scanning period (1
Although the polarity inversion is performed every H) and the row inversion is logically inverted every one vertical scanning period, any of column inversion, dot inversion, and frame inversion may be used.
Furthermore, in the embodiment, a normally black mode in which black is displayed in a state in which no voltage is applied is used, but a normally white mode in which white is displayed in a state in which no voltage is applied may be used.

Further, the number of gradation display is not particularly limited. Furthermore, in addition to R (red), G (green), and B (blue), for example, one pixel may be configured by four subpixels including C (cyan), and color display may be performed.
The liquid crystal panel 100 is not limited to the transmissive type, and may be a reflective type or a semi-transmissive / semi-reflective type intermediate between the two. Furthermore, a dye (guest) having anisotropy in absorption of visible light in a major axis direction and a minor axis direction of a molecule such as TN type or STN type is dissolved in a liquid crystal (host) having a certain molecular arrangement, A guest-host type liquid crystal in which dye molecules are arranged in parallel with liquid crystal molecules may be used. In addition, the liquid crystal molecules are aligned vertically with respect to both substrates when no voltage is applied, while the liquid crystal molecules are aligned horizontally with respect to both substrates when voltage is applied. Also good.
Furthermore, the present invention is not limited to the liquid crystal panel 100, and may be applied to an organic EL panel in which a current corresponding to the voltage or current of the data line 211 flows to the OLED element when selected, EL (electroluminescence), LED, SED Furthermore, the present invention can be applied to all display panels having different γ characteristics for each color, such as electrophoretic elements.

Next, an electronic apparatus having the electro-optical device 10 according to the above-described embodiment as a display device will be described. FIG. 15 is a perspective view showing a configuration of a mobile phone 1200 using the electro-optical device 10 according to the embodiment.
As shown in this figure, the mobile phone 1200 includes the liquid crystal panel 100 described above together with a plurality of operation buttons 1202, an earpiece 1204 and a mouthpiece 1206. In the electro-optical device 10, components other than the liquid crystal panel 100 are built in the telephone, so that they do not appear as appearance.

Electronic devices to which the electro-optical device 10 is applied include a digital still camera, a laptop computer, a liquid crystal television, a viewfinder type (in addition to the mobile phone shown in FIG.
Or a monitor direct view type video recorder, a car navigation device, a pager, an electronic notebook, a calculator, a word processor, a workstation, a videophone, a POS terminal, a device equipped with a touch panel, and the like. And as a display device for these various electronic devices,
Needless to say, the above-described electro-optical device 10 is applicable.

1 is a block diagram illustrating a configuration of an electro-optical device according to a first embodiment of the invention. FIG. It is a figure which shows the structure of the sub pixel in the same electro-optical apparatus. It is a figure which shows the scanning signal etc. in the same electro-optical device. It is a figure which shows the data etc. in the same electro-optical apparatus. It is a figure which shows the transmittance-voltage characteristic of the same subpixel for every RGB. It is a figure which shows the conversion content of (gamma) conversion circuit in the same electro-optical apparatus. FIG. 6 is a diagram illustrating a configuration of an electro-optical device according to a second embodiment of the invention. It is a figure which shows the structure of the sub pixel in the same electro-optical apparatus. It is a figure which shows the scanning signal etc. in the same electro-optical device. It is a figure which shows the data etc. in the same electro-optical apparatus. It is a figure which shows the gradation code pulse in the same electro-optical device for every RGB. It is a figure which shows the structure of the electro-optical apparatus which concerns on the application example of this invention. It is a figure which shows the structure of the sub pixel in the same application form. It is a figure which shows the scanning signal etc. in the same electro-optical device. It is a figure which shows the structure of the mobile telephone using the electro-optical apparatus which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electro-optical apparatus, 108 ... Common electrode, 110 ... Pixel, 116 ... TFT, 120 ... Subpixel, 211 ... Data line, 220 ... TFD, 250 ... Data line drive circuit, 311 ... Scan line, 350 ... Scan line drive Circuit 400 control circuit 1200 mobile phone

Claims (7)

One pixel is displayed by sub-pixels of m (m is an integer of 3 or more) color,
The sub-pixel has n (n) on one scanning line at the intersection of the plurality of scanning lines and the plurality of data lines.
Is an integer that satisfies m>n> 0), and is a display device that has gradation corresponding to the voltage or current of the corresponding data line when the scanning line is selected, and is provided so as to correspond to the color. ,
A scanning line driving circuit for selecting the plurality of scanning lines in a predetermined order;
The data line for converting the gradation data designating the gradation of the sub-pixel of the selected scanning line into a data signal of voltage or current corresponding to the voltage or current characteristics with respect to the gradation for each color of the sub-pixel. And a data line driving circuit for supplying to the display. The sub-pixel is
When a pixel electrode and a corresponding scanning line are selected, the pixel electrode has a three-terminal switching element that is in a conductive state between the data line and the pixel electrode, and corresponds to the voltage or current of the pixel electrode The display device according to claim 1, which has gradation. The display device
A characteristic change circuit and a conversion circuit;
The characteristic changing circuit sets, in the conversion circuit, a voltage or current characteristic for a gradation corresponding to a color of a sub-pixel of a selected scanning line among voltage or current characteristics for a predetermined gradation,
The conversion circuit converts the gradation data into sub-pixel data indicating voltage or current according to a voltage or current characteristic with respect to the gradation set by the characteristic changing circuit,
The display device according to claim 2, wherein the data line driving circuit generates a data signal based on the sub-pixel data. The sub-pixel is
A series connection of a capacitor, a pixel electrode, and a corresponding scanning line is selected, and a two-terminal switching element that becomes conductive when a predetermined selection voltage is applied is connected between the corresponding scanning line and the data line. Which is inserted in
The display device according to claim 1, wherein the gradation is in accordance with the effective voltage value held by the capacitor. The display device
A pulse interval setting circuit and a pulse generation circuit;
The scanning line driving circuit applies a selection voltage for bringing the switching element into a conductive state to the selected scanning line,
The pulse interval setting circuit sets an interval of pulse signals that defines a voltage switching timing of a data signal for each gradation in a period during which the selection voltage is applied, according to the color of a sub-pixel of a selected scanning line. Set in the generation circuit,
The pulse generation circuit outputs the pulse signal at an interval set by the pulse generation circuit,
The display device according to claim 4, wherein the data line driving circuit switches the voltage of the data signal at a switching timing corresponding to a gradation specified by the gradation data. When m is 3 and n is 2, the three color sub-pixels are red, green and blue,
One scan line is associated with red and green sub-pixels and the other scan line is associated with blue sub-pixels,
The one pixel is made to correspond to two columns of data lines, the data line of one column is connected to the red sub-pixel, and the data line of the other column is connected to both the green and blue sub-pixels. The display device according to claim 1. An electronic apparatus comprising the display device according to claim 1.

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