JP2008083483A - Electrooptical device and driving method thereof, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device that achieves display using sub-pixels of four colors R, G, B, and W under simple and effective control. <P>SOLUTION: The electrooptical device has, in a signal converter 100, a white signal arithmetic unit which receives inputs of an RGB color signals comprising a red signal Ri, a green signal Gi, and a blue signal Bi corresponding to a sub-pixel D<SB>R</SB>for red output, a sub-pixel D<SB>G</SB>for green output, and a sub-pixel D<SB>B</SB>for blue output respectively and then calculates the output level W of a white signal Wo corresponding to a sub-pixel D<SB>W</SB>for white output through an arithmetic operation using output levels R, G, and B (0<R, G, B<1) of the respective color signals of the RGB color signals and an operational expression (1): W=(aR+bG+cB)<SP>d</SP>(where 0<a, b, c<1, 1≤d≤4). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electro-optical device, a driving method thereof, and an electronic apparatus.

As a liquid crystal device, there are known four-color pixels in which W (white) is further added to the three primary colors of R (red), G (green), and B (blue) to enhance brightness ( For example, see Patent Document 1). In this type of liquid crystal device, if the white color is simply added, the display color will be different from the original image. Therefore, in the liquid crystal device described in Patent Document 1, the original image is formed in order to suppress a change in chromaticity. After the white component is added to the red, green, and blue color components, the display signal is generated by converting it to the color component ratio of the original image.
JP 2001-147666 A

  However, in the liquid crystal device described in Patent Document 1, it is necessary to provide a circuit that extracts a white component from an input image signal and a circuit that corrects each color component to which the white component has been added. This is also disadvantageous.

The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an electro-optical device that realizes display by RGBW four-color sub-pixels by simple and effective control. Yes.
It is another object of the present invention to provide a method for simply and effectively driving an electro-optical device including four sub-pixels of RGBW.

In order to solve the above-described problems, an electro-optical device according to an aspect of the invention includes an electric device including a pixel including a red output sub-pixel, a green output sub-pixel, a blue output sub-pixel, and a white output sub-pixel. An optical device that receives an RGB color signal composed of a red signal, a green signal, and a blue signal corresponding to the red output subpixel, the green output subpixel, and the blue output subpixel, respectively; Corresponding to the white output sub-pixel by calculation using the output level R, G, B (0 <R, G, B <1) of each color signal in the RGB color signal and the calculation formula shown in (1) below. And a white signal calculation unit that calculates an output level W of the white signal to be output.
W = (aR + bG + cB) ^d (1)
However, 0 <a, b, c <1, 1 ≦ d ≦ 4

According to the above configuration, since the white signal calculation unit capable of calculating the output level W of the white signal with an extremely simple calculation formula is provided, the RGB color signal (image signal) supplied from the host device is converted to an appropriate output level. Can be converted into an RGBW color signal including a white signal and supplied to four color sub-pixels.
Since the white color signal can be calculated from the output level of the RGB color signal by a simple arithmetic process using the above-described arithmetic expression (1), the load on the system is extremely small in securing the processing speed and the memory area, and therefore driving. It can be easily built into an IC and can be realized at low cost.

In the electro-optical device according to the aspect of the invention, the white color signal calculation unit may be provided, and the input RGB color signal may be the output level white signal calculated by the white signal calculation unit, and the red color signal constituting the RGB color signal. , A green signal, and a blue signal, a signal conversion unit that converts the signal into an RGBW color signal.
The electro-optical device may further include a drive circuit unit that converts the RGBW color signal output from the signal conversion unit into a data signal to be supplied to the corresponding subpixel.
Alternatively, the electro-optical device of the present invention may include an image processing unit that converts an input image signal into the RGB input signal.
As a mounting form of the white signal calculation unit, it may be mounted as a single circuit, or may be built in another circuit element.

In the electro-optical device according to the aspect of the invention, a coefficient storage unit that holds the luminance coefficient d of the arithmetic expression (1) so that it can be read from the white signal calculation unit and can be updated based on information input from an external control device. It can also be set as the structure provided.
According to this configuration, it is possible to easily realize an electro-optical device that can obtain brightness-enhanced display according to user preferences by user settings.

In the electro-optical device according to the aspect of the invention, an arithmetic expression applied to the arithmetic operation in the white signal arithmetic unit is expressed using the arithmetic expression (1) and correction coefficients a ′, b ′, and c ′. W = ( a′aR + b′bG + c′cB) ^d (1 ′)
And a coefficient storage unit that holds the correction coefficients a ′, b ′, and c ′ that can be read from the white signal calculation unit and that can be updated based on information input from an external control device. It can also be configured.
According to this configuration, the degree of contribution to the output level W of the red, green, and blue signals in the arithmetic expression (1 ′) can be adjusted.

  In the electro-optical device according to the aspect of the invention, the pixel may include the color output sub-pixels having four or more colors and the white output sub-pixel. In other words, the present invention can also be applied to an electro-optical device that includes four or more color display pixels. Even in the multicolor display electro-optical device having such a configuration, the supplied image signal is usually an RGB color signal, and therefore, the output level can be easily calculated using the above arithmetic expression. Therefore, also in this configuration, it is possible to obtain a display in which the output level of the white output sub-pixel is appropriately controlled.

An electro-optical device driving method according to the present invention includes a pixel including a red output sub-pixel, a green output sub-pixel, a blue output sub-pixel, and a white output sub-pixel. And receiving the RGB color signal composed of the red signal, the green signal, and the blue signal respectively corresponding to the red output sub-pixel, the green output sub-pixel, and the blue output sub-pixel, and the red signal The steps of deriving the output levels R, G, B (0 <R, G, B <1) of the green signal and the blue signal and calculating the output levels R, G, B by W = (aR + bG + cB) ^d A step of deriving an output level W of a white signal used for display of the white output sub-pixel by applying to an expression (where 0 <a, b, c <1, 1 ≦ d ≦ 4), and the output Level W white signal and RGB color signal Converting the signal to a data signal to be supplied to the sub-pixel of the corresponding color.
According to this driving method, the output level W of the white signal can be calculated with a very simple arithmetic expression, and the white output sub-pixel can be driven using the white signal obtained based on this. Therefore, according to the present invention, an electro-optical device having sub-pixels of four colors can be driven simply and effectively.
Since the white color signal can be calculated from the output level of the RGB color signal by a simple arithmetic process using the above-described arithmetic expression (1), a driving method that has a very low load on the system in securing the processing speed and memory area, Become.

An electronic apparatus according to an aspect of the invention includes the electro-optical device described above.
According to this configuration, the display unit that can be easily and effectively controlled and can easily obtain a display in which luminance is appropriately emphasized is provided.

According to another aspect of the invention, there is provided an electronic apparatus including an electro-optical device including a pixel including a red output sub-pixel, a green output sub-pixel, a blue output sub-pixel, and a white output sub-pixel, and the electro-optical device. And a control device that outputs an image signal to the red output sub-pixel, the green output sub-pixel, and the blue output sub-pixel. A signal conversion unit that converts an RGB color signal composed of a signal and a blue signal into an RGBW color signal composed of the RGB color signal and a white signal corresponding to the white output sub-pixel, and the signal conversion unit Receives the input of the RGB color signal, and outputs the output level R, G, B (0 <R, G, B <1) of each color signal in the RGB color signal and the arithmetic expression shown in the following (1). Depending on the operation used, Characterized in that it has a white signal calculation unit for calculating an output level W of the serial white signal.
W = (aR + bG + cB) ^d (1)
However, 0 <a, b, c <1, 1 ≦ d ≦ 4

  That is, the white signal calculation unit according to the present invention may be incorporated in an MPU or video controller provided as an external control device of the electro-optical device. According to the electronic apparatus having such a configuration, a general-purpose electro-optical device including sub-pixels of four or more colors can be easily and effectively controlled, and a display with appropriate brightness enhancement can be easily obtained. The display part which can be equipped is comprised.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1A is a diagram illustrating a schematic configuration of an electro-optical device according to the invention. FIG. 1B is a diagram showing a configuration of the drive IC 110 shown in FIG.

As shown in FIG. 1 (a), the electro-optical device of the present embodiment, the sub-pixel D _R for red output, and subpixel D _G for green output, and subpixel D _B for blue output, sub for white output The pixel D is configured to include a pixel P including four sub-pixels of the pixel _DW , and a driving IC 110 electrically connected to the pixel P.
The drive IC 110 includes a signal conversion unit 100 and a drive circuit unit 101 as shown in FIG. The signal conversion unit 100 converts an RGB color signal RGBi supplied from an external MPU (microprocessor) (not shown) or a video controller into an RGBW color signal (Ro, Go, Bo, Wo) added with a white signal and outputs the RGBW signal. To do.

The signal conversion unit 100 receives a RGB color signal and stores a white signal generation unit 105 including a white signal calculation unit that calculates an output level of the white signal, and a coefficient used for calculation in the white signal generation unit 105 And a coefficient storage unit 106.
The white signal calculation unit includes output levels R, G, B (0 <R, G, B <1) of the red signal Ri, the green signal Gi, and the blue signal Bi constituting the RGB color signal, and the following (1). The output level W of the white signal Wi corresponding to the white output sub-pixel _DW is calculated by calculation using the calculation formula.

W = (aR + bG + cB) ^d (1)
However, 0 <a, b, c <1, 1 ≦ d ≦ 4

In the arithmetic expression (1), the coefficients a, b, c and the luminance coefficient d are constants set in advance in the electro-optical device.
Coefficients a, b, c (0 < a, b, c <1) , for example, the sub-pixel _{D R,} considering the relationship between the D G, the light intensity and the pixel P overall brightness emitted from _{D B} Can be set. In this case, it is preferable to set (a, b, c) = (0.2998, 0.5868, 0.1144). According to this setting, the weighting of the output level G of the green signal Gi that is viewed relatively brightly in the pixel P to the output level W of the white signal is relatively large, and the other color signals Ri and Bi are also bright. Therefore, when an RGB color signal for displaying the pixel P brightly is input, the white output sub-pixel _DW can be effectively turned on, and the chromaticity changes greatly. Can be prevented. Therefore, it is possible to display with enhanced brightness while maintaining display quality.

The luminance coefficient d (1 ≦ d ≦ 4) is a coefficient that determines the rate of change of the output level W of the white signal with respect to the increase / decrease of the output level R, G, B of the RGB color signal. FIG. 2 shows a curve of the output level W obtained when the coefficient d is changed in the range of 1 to 3. As shown in FIG. 2, by increasing the luminance coefficient d, the gradient of the output level W increases as the region (high luminance region) having a larger value (aR + bG + cB) that reflects the output level of the entire RGB color signal. An arithmetic expression can be set. If d = 4, the difference between the slope of the output level W in the low brightness area and the slope of the output level W in the high brightness area can be further increased.
The setting value of the luminance coefficient d is preferably d = 2. With this setting, the output of the white output sub-pixel _DW is set to be lower than that when d = 1 in the low-luminance pixel. The change in the output of the white output sub-pixel _DW becomes large in the high-luminance pixel, so that the change in the brightness of the pixel P can be further emphasized.

The drive circuit unit 101 includes at least a data signal generation unit that converts the RGBW color signal supplied from the signal conversion unit 100 into data signals (gradation data) Sr, Sg, Sb, Sw of sub-pixels of the corresponding color. And a signal output unit for outputting these data signals to the sub-pixels D _R , D _G , D _B , and D _W in synchronization with the selection operation of each sub-pixel. Then, the RGBW color signal supplied from the signal conversion unit 100 is converted into data signals (gradation data) Sr, Sg, Sb, Sw of the corresponding color sub-pixels, and for each sub-pixel of the corresponding color. Output.

The electro-optical device of the present embodiment having the above configuration receives an input of the RGB color signal RGBi from the MPU or video controller (not shown) to the drive IC 110 and inputs it to the drive IC 110.
In the drive IC 110, the input RGB color signal RGBi is input to the signal conversion unit 100.
The signal conversion unit 100 derives the output levels R, G, and B (0 <R, G, B <1) of the input RGB color signal in the white signal calculation unit of the built-in white signal generation unit 105. Thereafter, the output level W of the white signal is calculated by calculation using the output levels R, G, and B obtained above and the above equation (1), the white signal Wo of the obtained output level, and the input color An RGBW color signal composed of the color signals Ro, Go, Bo using the signals Ri, Gi, Bi as they are as output signals is output to the drive circuit unit 101.
The driving circuit unit 101, the data signal Sr for the sub-pixel of a color corresponding to the inputted RGBW color signals, Sg, Sb, and outputs the converted Sw, the input of such data signals, the sub-pixel D _R , D _G , D _B , and D _W are turned on in accordance with the output level of the data signal, resulting in a display in which the pixel P is a color mixture of these sub-pixels.

In the above configuration, the luminance coefficient d is held in the coefficient storage unit 106 so as to be readable from the white signal calculation unit, and can be updated based on information input from the external control device. That is, the value of the luminance coefficient d held in the coefficient storage unit 106 can be changed from the outside, and the setting of the luminance coefficient d can be changed by the user. As described above, the electro-optical device according to the present embodiment allows the user to set the brightness enhancement degree according to preference. In addition to the user input, the luminance coefficient d reset by the external control device based on the detection information of the brightness sensor provided in the external device may be input.
The luminance coefficient d held in the coefficient storage unit 106 may be read from the coefficient storage unit 106 and substituted into the calculation formula (1) every time the white signal calculation unit performs the calculation. The new luminance coefficient d may be read from the coefficient storage unit 106 only when the coefficient storage unit 106 is updated by the input of.

  Further, in the present embodiment, the coefficients a, b, and c of the arithmetic expression (1) can be configured to be changeable by an input from an external control device, similarly to the luminance coefficient d. The coefficients a, b, and c determine the contributions of the red, green, and blue signals to the output level W of the RGB color signal. Since the setting range is wide, an appropriate display is allowed when user settings are allowed without limitation. The state may be damaged, and resetting may be difficult. Therefore, in the present invention, it is preferable to correct the coefficients a, b, and c using correction coefficients a ′, b ′, and c ′ prepared separately. In this case, the coefficients are corrected by multiplying the coefficients a, b and c by correction coefficients a ', b' and c ', respectively. Then, the arithmetic expression (1) can be rewritten as the following arithmetic expression (1 ').

W = (a′aR + b′bG + c′cB) ^d (1 ′)

  When the correction coefficients a ′, b ′, and c ′ are used, these correction coefficients are held in the coefficient storage unit 106, and the correction coefficients a ′, b ′, and c ′ are updated by input from the external control device. Thus, it is possible to adjust the degree of contribution to the output level W of the red, green, and blue signals in the arithmetic expression (1 ′). Even when such a correction coefficient is used, in addition to updating based on user input, updating based on information input from an external control device with the operation of another control device is possible.

  According to the electro-optical device of the present embodiment described above, the RGB color signal (image signal) supplied from the host device is output at an appropriate output level by including the signal conversion unit 100 including the white signal calculation unit. Can be converted into an RGBW color signal including the white signal Wo. Since the white signal can be calculated from the output level of the RGB color signal by a simple arithmetic process using the above-described arithmetic expression (1), the load on the system is extremely high in securing the processing speed and memory area. Get smaller. Therefore, it can be easily built in the drive IC 110 and can be manufactured at low cost.

  In the electro-optical device according to the present embodiment, the coefficient storage unit 106 connected to the white signal generation unit 105 holds the luminance coefficient d or the correction coefficients a ′, b ′, and c ′ so as to be readable from the white signal calculation unit. Since these coefficients can be updated by input from the external control device, it is possible to adjust the brightness enhancement degree according to the user's preference.

  In the above-described embodiment, the case where the signal conversion unit 100 including the white signal calculation unit is built in the drive IC 110 has been described. However, the drive control system in the electro-optical device according to the invention is not limited to the above configuration, and for example, the configuration shown in FIG. 3 can also be applied.

FIG. 3A is a schematic configuration diagram illustrating a first modification of the electro-optical device according to the invention. The electro-optical device according to the first modification shown in FIG. 3A includes a pixel P composed of sub-pixels D _R , D _G , D _B , and D _{W of} four colors, a signal conversion unit 100A, and a drive circuit unit. 101A. In other words, in the above-described embodiment, the signal conversion unit 100 and the drive circuit unit 101 that are integrated with the drive IC 110 are provided as the signal conversion unit 100A and the drive circuit unit 101A that are separate circuits. By providing the signal conversion unit 100A as a separate circuit in this way, there is an advantage that the configuration of the present invention can be realized without changing the configuration of the drive circuit unit 101A and the pixel P with respect to the conventional configuration.

FIG. 3B is a schematic configuration diagram illustrating a second modification of the electro-optical device according to the invention. The electro-optical device according to the second modification shown in FIG. 3A includes an image processing unit 102 that receives an input of an image signal Video of another format such as a YUV signal or an NTSC composite signal, and outputs an RGBW color signal. Drive circuit unit 101A.
The image processing unit 102 includes an image conversion unit that converts an image signal, and a signal conversion unit 100 according to the present invention. In other words, the image processing unit 102 is a video controller including the signal conversion unit 100. The image processing unit 102 converts the input image signal Video into an RGB color signal in the image conversion unit, and inputs the RGB color signal to the signal conversion unit 100 to convert it into an RGBW color signal. The RGBW color signal is output to the drive circuit unit 101A.
In the second modification example having the above-described configuration, the electro-optical device with a built-in video controller is provided, so that versatility when mounted on an electronic device is increased. Further, the configuration of the present invention can be realized without changing the configuration of the drive circuit unit 101A and the pixel P with respect to the conventional configuration.

  In the configuration shown in FIGS. 1A and 3A, an image processing unit (video controller) that converts an image signal of another format into an RGB color signal is provided in front of the drive IC 110 or the signal conversion unit 100A. Of course, it may be provided. Further, in the configuration shown in FIG. 1A, the image processing unit may be built in the drive IC 110.

In each of the embodiments described above, the electro-optical device including the pixels P in which elongated rectangular sub-pixels are arranged in the width direction has been described. However, in the electro-optical device according to the invention, the sub-pixels in one pixel are The arrangement form and the number of sub-pixels are not limited to the above embodiment.
For example, as shown in FIG. 4A, four color sub-pixels D _R , D _G , D _B , and D _W are arranged in 2 rows × 2 columns, as shown in FIG. 4B. The configuration may be such that five color sub-pixels D _R , D _G (G1), D _G (G2), D _B , and D _W are arranged. Even in the case of a configuration including five color sub-pixels, the image signal supplied from the host device is usually an RGB color signal, so that the signal conversion that receives the RGB color signal and outputs the RGBW color signal is performed. With the configuration including the unit 100, a display in which the output level of the white signal is appropriately set can be obtained.

  Further, in the pixel configurations shown in FIGS. 1, 3, and 4, the area ratios of the sub-pixels of each color may be changed. In the present invention, since the coefficients a, b, and c, which are the contributions of the red, green, and blue signals to the output level W of the white signal, can be set in a wide range, the coefficients a, b depend on the area ratio of the sub-pixels of each color. , C can be adjusted to easily optimize the output of the white output sub-pixel.

(Configuration example of electro-optical device)
Hereinafter, a liquid crystal device and an organic EL device will be described as specific configuration examples of the electro-optical device according to the invention.

[Liquid Crystal Device]
FIG. 5A is a plan configuration diagram of a liquid crystal device which is an embodiment of the electro-optical device according to the present invention, and FIG. 5B is a cross-sectional configuration diagram of FIG.
The liquid crystal device 150 includes a liquid crystal panel (electro-optical device) 2 that is a display unit, and a backlight (illumination device) 5 disposed on the back side (the lower surface in the drawing) of the liquid crystal panel 2. .

  In the liquid crystal panel 2, a first substrate 22a and a second substrate 22b that are opposed to each other with a liquid crystal 32 interposed therebetween are bonded and integrated by a sealing material 23 provided annularly on the peripheral edge of these two substrates. The first substrate 22a constituting the display surface of the liquid crystal panel 2 of the present embodiment is formed from a translucent common electrode 26a, an alignment film (not shown), etc. on the surface of the substrate body 24a, which is a transparent substrate, on the liquid crystal layer side. The liquid crystal alignment control layer is formed. The second substrate 22b disposed on the side opposite to the display surface (the lower surface side in the drawing) is a transparent pixel electrode 26b, an alignment film (not shown) or the like on the surface on the liquid crystal layer side of the substrate body 24b that is a transparent substrate. The liquid crystal alignment control layer which consists of is provided. Between the two substrates 22a and 22b constituting the liquid crystal panel 2, granular spacers 29 for maintaining a constant distance (cell gap) between the substrates 22a and 22b are distributed.

  The backlight 5 is disposed on the light guide plate 15 made of a transparent resin material, the light source 16 disposed on one end face of the light guide plate 15, and the back side of the light guide plate 15 (on the opposite side to the liquid crystal panel 2). And a reflection plate 17. The light source 16 is configured by an LED (light emitting diode), a cold cathode tube, or the like. Light output from the light source 16 is introduced into the light guide plate 15 from the side end face of the light guide plate 15, and the light is reflected by the reflection plate 17. It is emitted as illumination light to the liquid crystal panel 2 side while being reflected.

  The liquid crystal panel 2 may be either a passive matrix type or an active matrix type, and the liquid crystal alignment form may be various known forms such as a TN type, a VAN type, an STN type, a ferroelectric type, and an antiferroelectric type. Can be taken. It is also possible to display color by arranging color filters on any of the substrates. Alternatively, a transflective liquid crystal display device may be configured by forming a reflective film having a light-transmitting portion such as an opening or a slit on the second substrate 22b.

  The second substrate 22b of the liquid crystal panel 2 is provided with a projecting portion 24c that projects to the outer peripheral side of the first substrate 22a. The projecting portion 24c is used as a mounting terminal forming region. A wiring pattern (not shown) is formed on the overhanging portion 24c, and the pixel electrode 26b of the second substrate 22b is electrically connected to the wiring pattern of the overhanging portion 24c via a switching element and a wiring pattern (not shown). . The common electrode 26a of the first substrate 22a is also electrically connected to the wiring pattern of the overhanging portion 24c through a wiring pattern and a conductive material (not shown). A driving IC 110 that electrically drives the liquid crystal panel 2 is mounted on the wiring pattern of the projecting portion 24c. As a mounting form of the driving IC 110, COG mounting, FPC mounting, or the like can be used.

In a display area formed on the inner side of the liquid crystal panel 2 surrounded by the sealing material 23, pixels P composed of sub-pixels D _R , D _G , D _B , and D _{W of} four colors are arranged in a matrix in a plan view. ing. The color type of each sub-pixel is determined by a color filter provided corresponding to each sub-pixel. The white output sub-pixel _DW has a configuration in which a colored color filter is not provided, or a configuration in which a transparent color filter is provided.

Here, FIG. 6 is an equivalent circuit diagram of a display area in which the sub-pixels are arranged. In the display area of the liquid crystal panel 2, the data lines 6a and the scanning lines 3a are arranged in a grid pattern, and sub-pixels that are image display units are arranged in the vicinity of their intersections. Accordingly, each of the sub-pixels D _R , D _G , D _B , and D _W constituting the pixel P is electrically connected to the driving IC 110 via the data line 6a and the scanning line 3a.

  Each of the plurality of sub-pixels arranged in a matrix is provided with a pixel electrode 26b. In the vicinity of the pixel electrode 26b, a TFT 30 serving as a switching element for controlling energization to the pixel electrode 26b is formed. A data line 6 a is electrically connected to the source of the TFT 30. Data signals S1, S2,..., Sn (data signals Sr, Sg, Sb, Sw shown in FIG. 1) are supplied to each data line 6a. The scanning line 3 a is electrically connected to the gate of the TFT 30. Scan signals G1, G2,..., Gm are supplied to the scanning line 3a in pulses at a predetermined timing. The pixel electrode 26 b is electrically connected to the drain of the TFT 30. When the TFT 30 as a switching element is turned on for a certain period by the scanning signals G1, G2,..., Gm supplied from the scanning line 3a, the data signals S1, S2,. Are written to the liquid crystal of each pixel at a predetermined timing.

  Data signals S1, S2,..., Sn written in the liquid crystal are held for a certain period by a liquid crystal capacitor formed between the pixel electrode 26b and a common electrode described later. In order to prevent the retained data signals S1, S2,..., Sn from leaking, a storage capacitor 70 is formed between the pixel electrode 26b and the capacitor line 3b, and is arranged in parallel with the liquid crystal capacitor. When a voltage signal is applied to the liquid crystal as described above, the alignment state of the liquid crystal changes depending on the applied voltage level. As a result, light incident on the liquid crystal is modulated to enable gradation display.

The liquid crystal device 150 configured as described above can display data signals Sr, Sg, Sb, Sw supplied from the driving IC 110 to the four-color sub-pixels D _R , D _G , D _B , D _W. Yes. Since the white signal calculation unit that can calculate the output level W of the white signal with an extremely simple calculation formula is provided, the RGB color signal (image signal) supplied from the host device is converted into the white signal Wo of an appropriate output level. Can be converted into an RGBW color signal including the data signal supplied to the four color sub-pixels. Since the white color signal can be calculated from the output level of the RGB color signal by a simple arithmetic process using the above-described arithmetic expression (1), the load on the system is extremely small in securing the processing speed and the memory area, and therefore driving. The liquid crystal device can be easily built into an IC and can be manufactured at low cost.

[Organic EL device]
FIG. 7A is a plan view of an organic EL device that is an embodiment of the electro-optical device of the present invention. FIG. 7B is a circuit configuration diagram of the organic EL device. FIG. 8A is a plan view showing the pixel structure of the organic EL device. FIG. 8B is a diagram showing a cross-sectional structure of the pixel P, and is taken along the line CC ′ of FIG.

As illustrated in FIG. 7A, the organic EL device 200 includes an element substrate 202 and a sealing substrate 230 that are disposed to face each other. A display area for displaying an image is formed between these substrates. The drive IC 110 is mounted in a region where the element substrate 202 protrudes from the sealing substrate 230. In the display area, pixels P including four color sub-pixels D _R , D _G , D _B , and D _W are arranged in a matrix in a plan view. The color type of each sub-pixel is determined by the emission color of the organic EL element provided corresponding to each sub-pixel. In this case, a white light emitting layer is formed in the white output subpixel _DW . Or you may comprise the organic EL apparatus of the aspect which combined the organic EL element provided with the white light emitting layer, and the color filter. In this case, the white color output sub-pixel _DW is not provided with a color filter or is provided with a transparent color filter.

As shown in FIG. 7B, in the display area of the organic EL device 200, a plurality of scanning lines 231, a plurality of signal lines 232 extending in a direction intersecting the scanning lines 231, and the signal lines 232 are arranged in parallel. A plurality of common power supply lines 233 extending in the same manner are wired, and a sub pixel D (D _R , D _G , D _B , D _W ) is provided at each intersection of the scanning line 231 and the signal line 232. The scanning line 231 and the signal line 232 are electrically connected to the driving IC 110, and a scanning signal and a data signal synchronized from the driving IC 110 are supplied to the scanning line 231 and the signal line 232, respectively. . In each of the sub-pixels D, a switching TFT 203 to which a scanning signal is supplied to the gate electrode via the scanning line 231 and a data signal (Sr, Sg, Sb, Sw) supplied from the signal line 232 via the switching TFT 203 are provided. , A driving TFT 204 to which a data signal held by the holding capacitor cap is supplied to the gate electrode, and a common feeding line when electrically connected to the common feeding line 233 via the driving TFT 204 A pixel electrode (anode) 223 into which a drive current flows from 233 and a light emitting layer 260 sandwiched between the pixel electrode 223 and the cathode 250 are provided.

  As shown in FIG. 8B, the organic EL device 200 of the present embodiment is a top emission type organic EL device that extracts emitted light in the light emitting layer 260 from the sealing substrate 230 side. Therefore, as the element substrate 202, an opaque substrate can be used in addition to a transparent substrate. As the transparent substrate, glass, quartz, resin (plastic, plastic film) or the like can be used, and a glass substrate is particularly preferably used.

On the element substrate 202, a circuit layer 205 including the driving TFT 204 of the light emitting element 253 and the like is formed. A first interlayer insulating layer 283 made of silicon oxide or the like is formed on the surface of the circuit layer 205. Over the first interlayer insulating layer 283, an organic insulating film (planarizing film) 284 mainly composed of a resin material such as acrylic or polyimide having photosensitivity, insulation and heat resistance is formed. . The organic insulating film 284 is formed in order to suppress surface irregularities due to the driving TFT 204, the source electrode 243, the drain electrode 244, and the like.
A reflective film 227 is formed on the surface of the organic insulating film 284. The reflective film 227 is preferably made of a highly reflective metal material such as Ag or Al. As shown in FIG. 8A, the reflective film 227 is formed wider than the formation region of the light emitting element 253 in plan view (when viewed from the normal direction of the element substrate).

  8B, an inorganic insulating film (passivation film 225) made of silicon oxide, silicon nitride, or the like is formed so as to cover the reflective film 227. The inorganic insulating film 225 is a reflective film. 227 and the pixel electrode 223, and has a function of preventing contact between the two and the inorganic insulating film 225. The inorganic insulating film 225 is a reflection film from an etching solution used for patterning the pixel electrode 223. 227 and the organic insulating film 284 are protected.

  A pixel electrode 223 made of a transparent conductive film such as ITO is formed on the inorganic insulating film 225. As shown in FIG. 8A, the pixel electrode 223 is formed wider than the formation region of the light emitting element 253, and the aperture ratio of the organic EL device is improved. A plurality of pixel electrodes 223 are arranged in a matrix. A contact hole 270 penetrating the organic insulating film is formed adjacent to the formation region of the light emitting element 253. Although not shown in FIG. 8B, the pixel electrode 223 and the drain electrode 244 of the driving TFT 204 are electrically connected through the contact hole 270.

  Returning to FIG. 8B, an organic partition 221 made of an organic insulating material such as polyimide is formed around the pixel electrode 223. The organic partition 221 is formed so as to run over the peripheral edge of the pixel electrode 223, and the pixel electrode 223 is exposed at the bottom of the opening 221 a of the organic partition 221. A plurality of functional films are stacked on the surface of the pixel electrode 223 inside the opening 221a to form a light emitting element 253. That is, the formation region of the light emitting element 253 is defined by the opening 221 a of the organic partition 221.

The light-emitting element 253 is configured by stacking at least a pixel electrode 223 that functions as an anode, a light-emitting layer 260 made of an organic EL material, and a common electrode 250 that functions as a cathode. The light emitting elements 253 constitute sub-pixels D _R , D _G , D _B , and D _{W as} image display units, and one pixel P is constituted by a combination of light emitting elements of different color lights.

  An inorganic sealing film 241 made of silicon oxide or the like is formed on the surface of the common electrode 250. Further, a sealing substrate 230 made of a transparent material such as glass is bonded through an adhesive layer 240. The inorganic sealing film 241 prevents moisture, oxygen, and the like from entering the light emitting element 253 from the sealing substrate 230 side. Note that a sealing cap that covers the entire common electrode 250 may be fixed to the periphery of the element substrate 202, and a getter agent that absorbs moisture, oxygen, or the like may be disposed inside the sealing cap.

  In the top emission type organic EL device, since the common electrode 250 is formed in a thin film shape in order to improve the light extraction efficiency, the conductivity of the common electrode 250 is low. Therefore, as shown in FIG. 8A, a line-shaped auxiliary electrode 252 is formed on the surface of the common electrode. The auxiliary electrode 252 assists the conductivity of the above-described common electrode and is made of a metal material such as Al, Au, or Ag that has excellent conductivity. The auxiliary electrode 252 is disposed around the sub-pixel D in order to prevent the aperture ratio from being lowered.

  In the organic EL device described above, a data signal supplied from the outside is applied to the pixel electrode 223 by the driving TFT 204 at a predetermined timing. Then, holes injected from the pixel electrode 223 and electrons injected from the common electrode 250 are recombined in the light emitting layer 260, and light having a predetermined wavelength is emitted. The light emitted to the common electrode 50 side is taken out through the sealing substrate 230 made of a transparent material. Further, the light emitted to the pixel electrode 223 side is reflected by the reflective film 227 and is extracted from the sealing substrate 230 to the outside. Thereby, image display is performed on the sealing substrate 230 side.

The organic EL device 200 having the above configuration can display data signals Sr, Sg, Sb, Sw supplied from the driving IC 110 to the sub-pixels D _R , D _G , D _B , and D _{W of} four colors. ing. Since the white signal calculation unit that can calculate the output level W of the white signal with an extremely simple calculation formula is provided, the RGB color signal (image signal) supplied from the host device is converted into the white signal Wo of an appropriate output level. Can be converted into an RGBW color signal including the data signal supplied to the four color sub-pixels.
Since the white color signal can be calculated from the output level of the RGB color signal by a simple arithmetic process using the above-described arithmetic expression (1), the load on the system is extremely small in securing the processing speed and the memory area, and therefore driving. The organic EL device can be easily built into an IC and can be manufactured at low cost.

(Electronics)
FIG. 9 is a perspective configuration diagram of a mobile phone which is an example of the electronic apparatus according to the invention. A cellular phone 1300 shown in the figure includes a plurality of operation buttons 1302, an earpiece 1303, a mouthpiece 1304, and a display unit 1301 including the electro-optical device (liquid crystal device or organic EL device) of the previous embodiment. It is prepared for. As such a cellular phone, a configuration in which an image signal transmitted to the display unit 1301 can be converted into an RGBW color signal including a white signal by a video controller or MPU including a white signal calculation unit is also applicable.

  The electronic apparatus provided with the electro-optical device according to the present invention is not limited to the above-mentioned ones. For example, digital cameras, personal computers, televisions, portable televisions, viewfinder type / monitor direct-view type video tapes. Examples include a recorder, a PDA, a portable game machine, a pager, an electronic notebook, a calculator, a clock, a word processor, a workstation, a videophone, a POS terminal, and a device equipped with a touch panel.

1 is a schematic configuration diagram of an electro-optical device and a drive IC according to the present invention. FIG. 5 is an explanatory diagram of the function of a luminance coefficient d. FIG. 9 is a diagram illustrating a modification of the electro-optical device according to the invention. FIG. 10 is a diagram illustrating another pixel configuration of the electro-optical device according to the invention. 1 is a diagram showing a liquid crystal device which is an example of an electro-optical device of the invention. FIG. 2 is an equivalent circuit diagram of the liquid crystal device. FIG. 3 is an equivalent circuit diagram of an organic EL device that is an example of the electro-optical device of the invention. The figure which shows the pixel structure of an organic electroluminescent apparatus. FIG. 14 illustrates an example of an electronic device.

Explanation of symbols

P pixel, D _R , D _G , D _B , D _W sub-pixel, 100, 100A signal conversion unit, 101, 101A drive circuit unit, 102 image processing unit, 110 drive IC, 105 white signal generation unit (white signal calculation unit) ), 106 Coefficient storage unit

Claims (10)

An electro-optical device including a pixel including a red output sub-pixel, a green output sub-pixel, a blue output sub-pixel, and a white output sub-pixel,
Each color in the RGB color signal is received by receiving an RGB color signal composed of a red signal, a green signal, and a blue signal respectively corresponding to the red output sub-pixel, the green output sub-pixel, and the blue output sub-pixel. Signal output levels R, G, B (0 <R, G, B <1) and the output level of the white signal corresponding to the white output sub-pixel by calculation using the calculation formula shown in (1) below An electro-optical device comprising a white signal calculation unit for calculating W.
W = (aR + bG + cB) ^d (1)
However, 0 <a, b, c <1, 1 ≦ d ≦ 4 Comprising the white color signal calculation unit;
The input RGB color signal is converted into an RGBW color signal composed of a white signal having an output level calculated by the white signal calculation unit and a red signal, a green signal, and a blue signal constituting the RGB color signal. The electro-optical device according to claim 1, further comprising a signal conversion unit.   The electro-optical device according to claim 2, further comprising: a drive circuit unit that converts the RGBW color signal output from the signal conversion unit into a data signal supplied to the corresponding sub-pixel.   4. The electro-optical device according to claim 1, further comprising an image processing unit that converts an input image signal into the RGB input signal.   A coefficient storage unit that holds the luminance coefficient d of the calculation formula (1) so as to be readable from the white signal calculation unit and to be updated based on information input from an external control device is provided. The electro-optical device according to any one of 1 to 4. An arithmetic expression applied to the calculation in the white signal calculation unit is expressed using the arithmetic expression (1) and correction coefficients a ′, b ′, and c ′. W = (a′aR + b′bG + c′cB) ^d ……… (1 ')
And the formula
A coefficient storage unit that holds the correction coefficients a ′, b ′, and c ′ so as to be readable from the white signal calculation unit and to be updated based on information input from an external control device is provided. Item 5. The electro-optical device according to any one of Items 1 to 4.   The electro-optical device according to claim 1, wherein the pixel includes the color output sub-pixels having four or more colors and the white output sub-pixel. A driving method of an electro-optical device including a pixel including a red output sub-pixel, a green output sub-pixel, a blue output sub-pixel, and a white output sub-pixel,
The red signal, the green signal, and the red signal, the green signal, and the blue signal, respectively. And deriving output levels R, G, B (0 <R, G, B <1) of the blue signal;
The output levels R, G, B are applied to an arithmetic expression W = (aR + bG + cB) ^d (where 0 <a, b, c <1, 1 ≦ d ≦ 4), and the display of the white output sub-pixels Deriving the output level W of the white signal provided to
Converting the white signal of the output level W and the RGB color signal into a data signal to be supplied to the sub-pixel of the corresponding color;
A method for driving an electro-optical device.   An electronic apparatus comprising the electro-optical device according to claim 1. An electro-optical device including a pixel including a red output sub-pixel, a green output sub-pixel, a blue output sub-pixel, and a white output sub-pixel, and a control device that outputs an image signal to the electro-optical device An electronic device comprising:
The control device converts an RGB color signal composed of a red signal, a green signal, and a blue signal respectively corresponding to the red output subpixel, the green output subpixel, and the blue output subpixel into the RGB color signal and the blue signal. A signal conversion unit for converting into an RGBW color signal composed of a white signal corresponding to a white output sub-pixel;
The signal converter receives the RGB color signal and outputs the output level R, G, B (0 <R, G, B <1) of each color signal in the RGB color signal and (1) below. An electronic apparatus comprising: a white signal calculation unit that calculates an output level W of the white signal by calculation using an arithmetic expression.
W = (aR + bG + cB) ^d (1)
However, 0 <a, b, c <1, 1 ≦ d ≦ 4

Images