BACKGROUND
[0001] The invention relates to panel displays, and more particularly, to systems and methods
for providing driving voltages to RGBW display panels.
[0002] Color image display devices are well known and are based upon a variety of technologies
such as cathode ray tubes, liquid crystal modulators and solid-state light emitters
such as Organic Light Emitting Diodes (OLEDs). In a common OLED color image display
device, a pixel includes red, green and blue colored subpixels. These light emitting
colored subpixels define a color gamut, and by additively combining the illumination
from each of these three subpixels, i.e. with the integrative capabilities of the
human visual system, a wide variety of colors can be achieved. OLEDs may be used to
generate color directly using organic materials to emit energy in desired portions
of the electromagnetic spectrum, or alternatively, broadband emitting (apparently
white) OLEDs may be attenuated with color filters to achieve red, green and blue output.
[0003] Images and data displayed on a color display device are typically stored and/or transmitted
in three channels, that is, having these signals corresponding to a standard (e.g.
RGB). It is also important to recognize that data typically is sampled to assume a
particular spatial arrangement of light emitting elements. In an OLED display device,
these light emitting elements are typically arranged side by side on a plane. Therefore,
if incoming data is sampled for display on a color display device, the data will also
be resampled for display on an OLED display having four subpixels per pixel rather
than the three subpixels used in a three channel display device.
[0004] In this regard, Fig. 1A shows a conventional OLED subpixel driving circuit structure,
and Fig. 1B shows RGBW subpixel arrangements of a conventional display panel. As shown
in Fig. 1A, the subpixel is driven by the current 11 through the driving transistor
T1. The driving transistor T1 outputs the current 11 according to the voltage V1.
[0005] Fig. 1C shows a conventional digital signal processing (DSP) structure for driving
RGBW subpixels. As shown in Fig. 1C, RGB digital signals are sampled and held and
output to a Gamma linear control unit. The Gamma linear control unit adjusts RGB digital
signals for Gamma linearity and outputs to the conversion unit. The conversion unit
converts the adjusted RGB digital signals to RGBW digital signals and outputs to a
Gamma compensation unit. The Gamma compensation unit executes a Gamma compensation
of the RGBW digital signals from the conversion unit for Gamma correction and outputs
to a RGBW driver. The RGBW driver converts the RGBW digital signals to RGBW analog
signals to drive corresponding RGBW subpixels.
[0006] Fig. 2A shows the relationship between the luminance of the OLED subpixel and the
current I1. As shown, there is a linear relationship between the luminance of the
OLED subpixel and the current I1. Fig. 2B shows the relationship between the current
I1 of the driving transistor T1 and the voltage V1 to be non-linear. Fig. 2C shows
the relationship between luminance of the OLED subpixel and observable brightness
(gamma). Fig. 2D shows the relationship between observable brightness and voltage
V1 applied to the driving transistor T1.
[0007] Thus, a gamma correction is required to compensate the non-linear relationship.
[0008] Conventionally, RGB data is converted to RGBW data through digital data processing
(DSP). However, due to different optical characteristics (gamma correction) for each
RGBW color, DSP typically requires a complicated algorithm to execute such conversion.
Further, it may be difficult to obtain a precise analog output corresponding to the
gamma correction for each color after using the complicated conversion algorithm.
[0009] For example, Fig. 3 shows a conventional method for converting RGB data to RGBW data.
As shown in Fig. 3, the Min(R,G,B) is assumed to be W data, and R'G'B' data (driving
the display device) can be obtained by removing the W component from the R,G,B components
respectively. Fig. 4 shows another conventional method for converting RGB data to
RGBW data. As shown in Fig. 4, the Min(R,G,B) is assumed to be W data, and the W component
is converted to W' data in accordance with a characteristic of α*W, where α <1. The
R'G'B' data are obtained by removing the W' component from the RGB components respectively.
However, these two simple methods typically cannot precisely provide gamma correction
for each color because of the non-linear relationship between driving voltage and
observable brightness.
[0010] A method and system according to the preamble of the independent claims is described
in the article "6-bit AMOLED with RGB Adjustable Gamma Compensation LTPS TFT Circuit"
written by Y. Matsueda et al. and published in SID 05 Digest on pages 1352 - 1355.
For displaying image the system includes a data driver comprising an average brightness
extraction unit. The system further includes a reference voltage generation circuit
adapted to provide first to third sets of reference voltages suitable for the red,
green and blue sub-pixels, wherein the reference voltage generation circuit at least
comprises first, second and third voltage generators. The system also comprises a
digital-to-analog (D/A) conversion unit adapted to generate driving voltages to drive
the red, green and blue sub-pixels and a display panel comprising the red, green and
blue sub-pixels adapted to generate color images according to the driving voltages.
[0011] From
EP 1 298 637 A2 a similar system is known, namely a "liquid crystal display" including a reference
voltage generator changing the level of a first predetermined voltage based on a first
signal to generate a reference voltage. The first signal varies depending on one of
the brightness of the surroundings of the liquid crystal display, brightness of the
on-screen images of the liquid crystal display and a user's manipulation (see par.
[0006]).
[0012] Further methods for providing driving voltages of a system for displaying images
are described in
EP 0 547 603 A2; US 2004 / 0 113 875 A1 or
US 6 593 934 B1.
[0013] From the above mentioned documents RGB based display systems and methods are known
which are adapted to select gamma characteristics based on the average image brightness
which is extracted from the three color input signals (R. G, B). Thus a conversion
of RGB data into RGBW has to be performed, if these known methods shall be applied
to RGBW panels. However, in conventional systems the conversion requires DSP processing
of a complicated algorithm due to gamma correction. Thus high efforts are needed to
achieve an accurately controlled gamma correction for RGBW brightness.
[0014] It is therefore object of the present invention to provide a system and a method
which can more easily provide an accurately controlled gamma correction for RGBW brightness.
[0015] The object is solved by a system having the features of claim 1 and by a method having
the features of independent claim 10.
[0016] Accordingly the invention proposes to execute an AND logic operation to red, green
and blue input signals controlling brightness of the red, green and blue sub-pixels
respectively to extract the white component signal; to generate first to fourth sets
of reference voltages suitable for the red, green, blue and white sub-pixels, wherein
the first to third sets of reference voltages suitable for the red, green and blue
sub-pixels are generated according to the white component signal; and to generate
the driving voltages to drive the red, green, blue and white sub-pixels according
to the first to fourth sets of reference voltages, the red, green and blue input signals
and the white component signal. The system of the invention shall comprise a white
component extraction unit which is adapted to execute an AND logic operation to the
red, green and blue input signals controlling brightness of the red, green and blue
sub-pixels respectively, to extract the white component signal. The reference voltage
generation circuit shall be adapted to provide first to fourth sets of reference voltages
suitable for the red, green, blue and white sub-pixels, wherein the first to third
sets of reference voltages suitable for the red, green and blue sub-pixels are generated
according to the white component signal, wherein the first, second and third voltage
generators each comprise: first and second resistor strings connected to each other
in series, each comprising a plurality of resistors and nodes. The first, second and
third voltage generators shall further comprise a first de-multiplexer adapted to
selectively make connections between a first power voltage and one of the nodes of
the first resistor string according to the white component signal; and a second de-multiplexer
adapter to selectively make connections between a second power voltage and one of
the nodes of the second resistor string according to the white component signal. Finally
the digital-to-analog (D/A) conversion unit shall be adapted to generate the driving
voltages to drive the red, green, blue and white sub-pixels according to the first
to fourth sets of reference voltages, the red, green and blue input signals and the
white component signal.
[0017] In summary the invention discloses a system and a method for providing driving voltages
of RGBW display panels.
[0018] An exemplary embodiment of such a system comprises a data driver with a reference
voltage generation circuit providing reference voltages according to a white component
signal (W) extracted from three color input signals (R,G,B), and a digital-to-analog
(D/A) conversion unit to generate driving voltages according to the reference voltages,
the three color input signals and the white component signal.
[0019] An exemplary embodiment of a method for providing driving voltages of a RGBW display
panel, comprises generating reference voltages according to a white component signal
(W) extracted from three color input signals (R,G,B); and generating driving voltages
according to the reference voltages, the three color input signals and the white component
signal.
DESCRIPTION OF THE DRAWINGS
[0020] The invention can be more fully understood by the subsequent detailed description
and examples with reference made to the accompanying drawings, wherein:
Fig. 1A shows a conventional OLED subpixel driving circuit structure;
Fig. 1B shows RGBW pixel arrangements of conventional display panel;
Fig. 1C shows a conventional digital signal processing (DSP) structure for driving
RGBW pixels;
Fig. 2A shows the relationship between the luminance of OLED and current;
Fig. 2B shows the relationship between current through the control transistor and
driving voltage thereof;
Fig. 2C shows the relationship between luminance of the OLED and observable brightness;
Fig. 2D shows the relationship between observable brightness and driving voltage of
driving transistor;
Fig. 3 shows a conventional method for converting RGB data to RGBW data;
Fig. 4 shows another conventional method for converting RGB data to RGBW data;
Fig. 5 shows an embodiment of a data driver;
Figs. 6A-6D show embodiments of a voltage generator;
Fig. 7 shows another embodiment of a data driver;
Figs. 8-1 and 8-2 show another embodiment of a data driver;
Fig. 9 is a schematic diagram of an embodiment of a display; and
Fig. 10 is a schematic diagram of an embodiment of an electronic device employing
the display panel shown in Fig. 9.
DETAILED DESCRIPTION
[0021] Systems for providing driving voltages to display panels will now be described with
reference to several exemplary embodiments. In this regard, an embodiment of a system
providing driving voltages to an RGBW display panel is depicted in Fig. 5. As shown
in Fig. 5, data driver 100A comprises a white component extraction unit 10, an analog
reference voltage generation circuit 20 and N digital-to-analog (D/A) conversion units
30_1A∼30_NA.
[0022] The white component extraction unit 10 extracts a white component signal Wi from
three color input signals Ri, Gi and Bi. For example, three color input signals Ri,
Gi and Bi can be 6 bit digital data. If color input signals R1, G1 and B1 are 110111,
010111 and 000111 respectively, the white component signal W1 can be 000111. Alternately,
white component extraction unit 10 can output a suppressed white component signal
W1 of 000011 according to the color input signal R1, G1 and B1.
[0023] The white component signal Wi can be obtained by executing an AND logic operation
to the three color input signals Ri, Gi and Bi. For example, when the color input
signals R1, G1 and B1 are 110111, 010111 and 000111 respectively, the white component
signal W1 can be 000111.
[0024] Conversely, the white component signal Wi can be obtained by executing an AND logic
operation to M bits of the three color input signals Ri, Gi, Bi, and 0 < M < 6. For
example, when M=2, a suppressed white component signal W1 of 000011 can be obtained
according to the color input signal R1, G1 and B1.
[0025] The analog reference voltage generation circuit 20 generates four sets of reference
voltages V0
R∼V63
R, V0
G∼V63
G, V0
B∼V63
B and V0
W∼V63
W for color input signal Ri, Gi and Bi and the white component signal Wi respectively,
the reference voltages V0
R∼V63
R, V0
G∼V63
G and V0
B∼V63
B are generated according to the white component signal Wi.
[0026] The D/A conversion units 30_1A∼30_NA receive the reference voltages VO
R∼V63
R, V0
G∼V63
G, V0
B∼V63
B and V0
W∼V63
W from the analog reference voltage generation circuit 20 to generate corresponding
driving voltages VA1
R∼VAN
R, VA1
G∼VAN
G, VA1
B∼VAN
B and VA1
W∼VAN
W according to the three color input signals Ri, Gi and Bi and the white component
signal Wi. For example, the D/A conversion unit 30_1A receives the reference voltages
V0
R∼V63
R, V0
G∼V63
G, V0
B∼V63
B and V0
W∼V63
W and generates corresponding driving voltages VA1
R, VA1
G, VA1
B and VA1
W according to the three color input signals R1, G1 and B1 and the white component
signal W1 during a first period. The D/A conversion unit 30_2A receives the reference
voltages V0
R∼V63
R, V0
G∼V63
G, V0
B∼V63
B and V0
W∼V63
W and generates corresponding driving voltages, VA2
R, VA2
G, VA2
B and VA2
W according to the three color input signals R2, G2 and B2 and the white component
signal W2 during a second period, and so on. Namely, all D/A conversion units 30_1A∼30_NA
employ the same type of analog reference voltage circuit which can generate different
reference voltages V0
R∼V63
R, V0
G∼V63
G, V0
B∼V63
B and V0
W∼V63
W according to different white component signals Wi during different periods.
[0027] The D/A conversion units 30_1A~30_NA each comprise four sampling latches S1
R~S1
W, four holding latches H1
R~H1
W, four D/A converters DAC_R~DAC_W and four analog buffers AB_R~AB_W. The sampling
latches S1
R~S1
W sample the color input signals Ri, Gi and Bi and the white component signal Wi at
one time. The holding latches H1
R~H1
W hold the color input signals Ri, Gi and Bi and the white component signal Wi sampled
by the sampling latches S1
R~S1
W. The D/A converters DAC_R~DAC_W convert the held color input signals Ri, Gi and Bi
and the held white component signal Wi to corresponding analog voltages VA1
R~VA1
W according to the reference voltages V0
R~V63
R, V0
G~V63
G, V0
B~V63
B and V0
W~V63
W, and output the corresponding driving voltages VA1
R~VA1
W through the analog buffers AB_R~AB_W. Operation and structure of the D/A conversion
units 30_2A~30_NA are similar to those of the D/A conversion unit 30_1A. In this embodiment,
the data diver 100A can output four corresponding voltages to drive four data lines
at one time.
[0028] The analog reference voltage generation circuit 20 comprises four voltage generators
22R, 22G, 22B and 22W shown in Figs. 6A~6D to generate reference voltages V0
R~V63
R, V0
G~V63
G, V0
B~V63
B and V0
W~V63
W. As shown in Fig. 6A, the voltage generator 22R generates the reference voltages
V0
R~V63
R to D/A converters DAC_R of the D/A conversion units 30_1A~30_NA according to the
white component signal Wi. The voltage generator 22R comprises two de-multiplexers
211 and 212 and two series-connected resistor strings 231 and 232. The resistor string
231 comprises resistors R0
R"~R62
R" connected in series, and the resistor string 232 comprises resistors R0
R~R64
R for red color grey level gamma correction. The de-multiplexer 211 selectively outputs
a first power voltage VerfH to one node of the resistor string 231 according to the
white component signals Wi, and the de-multiplexer 212 selectively outputs a second
power voltage VrefL to one node of the resistor string 232 according to the white
component signals Wi. The first power voltage VrefH exceeds the second power voltage
VrefL, the resistors R0
R" and R0
R are the same, the resistors R1
R" and R1
R are the same, the resistors R2
R" and R2
R are the same, and so on.
[0029] For example, if the white component signal Wi extracted from the three color input
signals Ri, Gi and Bi is 000000, the power voltage VrefL is forced to the node N0
of the resistor string 232, and the power voltage VrefH is forced to the node N3 of
the resistor string 231. Alternately, if the white component signal Wi extracted from
the three color input signals Ri, Gi and Bi is 000001, the power voltage VrefL is
forced to the node N1 of the resistor string 232, and the power voltage VrefH is forced
to the node N4 of the resistor string 231. Accordingly, the voltage level of the reference
voltage V0
R~V63
R for the red input signal Ri can be lowered by a first voltage drop.
[0030] Alternately, if the white component signal Wi extracted from the three color input
signals Ri, Gi and Bi is 000010, the power voltage VrefL is forced to the node N2
of the resistor string 232, and the power voltage VrefH is forced to the node N5 of
the resistor string 231. Accordingly, the voltage level of the reference voltage V0
R~V63
R for the red input signal Ri can be lowered by a second voltage drop exceeding the
first voltage drop. Thus, the voltage level of the reference voltage V0
R~V63
R for the red input signal Ri can be adjusted based on the white component signal Wi.
[0031] As shown in Fig. 6B, the voltage generator 22G generates the reference voltages V0
G~V63
G to D/A converters DAC_G of the D/A conversion units 30_1A~30_NA according to the
white component signal Wi. The voltage generator 22R comprises two de-multiplexers
213 and 214 and two series-connected resistor strings 233 and 234. The resistor string
233 comprises resistors R0
G"~R62
G" connected in series, and the resistor string 234 comprises resistors R0
G~R64
G for green color grey level gamma correction. The de-multiplexer 213 selectively outputs
the first power voltage VrefH to one node of the resistor string 233, and the de-multiplexer
214 selectively outputs the second power voltage VrefL to one node of the resistor
string 234. The resistors R0
G" and R0
G are the same, the resistors R1
G" and R1
G are the same, the resistors R2
G" and R2
G are the same, and so on.
[0032] As shown in Fig. 6C, the voltage generator 22B generates the reference voltages V0
B~V63
B to D/A converters DAC_B of the D/A conversion units 30_1A~30_NA according to the
white component signal Wi. The voltage generator 22B comprises two de-multiplexers
215 and 216 and two series-connected resistor strings 235 and 236. The resistor string
235 comprises resistors R0
B"~R62
B" connected in series, and the resistor string 236 comprises resistors R0
B~R64
B for blue color grey level gamma correction. The de-multiplexer 215 selectively outputs
the first power voltage VrefH to one node of the resistor string 235, and the de-multiplexer
216 selectively outputs the second power voltage VrefL to one node of the resistor
string 236. The resistors R0
B" and R0
B are the same, the resistors R1
B" and R1
B are the same, the resistors R2
B" and R2
B are the same, and so on. Operation of the voltage generator 22G and 22B is similar
to that of the voltage generator 22R., . The resistors R0
R~R64
R, R0
G~R64
G and R0
B~R62
B can be different from others, depending on design.
[0033] As shown in Fig. 6D, the voltage generator 22W comprises a resistor string 237 comprising
a plurality of resistors R0
W~R63
W connected in series for white color grey level gamma correction. The power voltages
VrefH and VrefL are forced to two ends of the resistor string 237, such that the reference
voltages V0
W~V63
W are generated according to difference resistances of the resistors R0
W~R63
W.
[0034] In this embodiment , the voltage level of the reference voltages V0R~V63R, V0G~V63G
and V0B~V63B for three color input signals Ri, Gi and Bi can be adjusted based on
the white component signal Wi. The lower voltage level of the reference voltages V0
R~V63
R, V0
G~V63
G and V0
B~V63
B, the lower driving voltage VA1
R~VAN
R, VA1
G~VAN
G and VA1
B~VAN
B generated by D/A conversion units 30_1A~30_NA. Namely, the voltage level of the driving
voltages VA1
R~VAN
R, VA1
G~VAN
G and VA1
B~VAN
B generated by D/A conversion units 30_1A~30_NA can be adjusted according to the extracted
white component signal Wi. When N-type transistors are used as driving devices of
pixels, the RGB brightness of the subpixels on a display device is lowered as the
driving voltage decreases based on the white component signal Wi. In some embodiments,
when P-type transistors are used as driving devices of pixels, the RGB brightness
of the pixels on a display device is lowered as the driving voltage increases based
on the white component signal Wi. Thus, gamma correction for RGBW brightness can be
accurately controlled.
[0035] Alternately, in some embodiments, the de-multiplexers 211, 213 and 215 selectively
output the second power voltage VrefL to one node of the resistor string 231, 233
and 235, and the de-multiplexer 212, 214 and 216 selectively output the first power
voltage VrefH to one node of the resistor string 232, 234 and 236.
[0036] Fig. 7 shows another embodiment of a data driver. As shown, the data driver 100B
is similar to the data driver 100A shown in Fig. 5, with the exception of analog sampling
and holding latches ASH_R~ASH_W coupled between the analog buffers AB_R~AB_W and the
D/A converters DAC_R~DAC_W in each D/A conversion unit 30_1B~30_NB. Description of
the same structure shown in Fig. 5 is omitted for simplification. In the data driver
100B, the driving voltages VA1
R~VAN
R, VA1
G~VAN
G, VA1
B~VAN
B and VA1
W~VAN
W generated by the D/A conversion units 30_1B~30_NB during different periods can be
sampled and held by the analog sampling and holding latches ASH_R~ASH_W. Thus, the
data driver 100B can output the corresponding voltages to drive one row of data lines
in one time.
[0037] Figs. 8-1 and 8-2 show another embodiment of a data driver. As shown, the data driver
100C is similar to the data driver 100A shown in Fig. 5, with the exception of N analog
reference voltage generation circuits 20_1~20_N coupled to the D/A conversion units
30_1C~30_NC. Description of the same structure shown in Fig. 7 is omitted for simplification.
In the data driver 100C, the N analog reference voltage generation circuits 20_1~20_N
each correspond to one of the D/A conversion units 30_1C~30_NC. For example, the analog
reference voltage generation circuit 20_1 corresponds to the D/A conversion unit 30_1C,
the analog reference voltage generation circuit 20_2 corresponds to the D/A conversion
unit 30_2C, and so on. The color input signals Ri, Gi, Bi and the extracted white
component signal Wi are sampled by the sampling latches S1
R~S1
W and held by the holding latches H1
R~H1
W in the D/A conversion units 30_1C~30_NC during each period. For example, the color
input signals R1, G1, B1 and the extracted white component signal W1 are sampled and
held in the D/A conversion units 30_1C during a first period, the color input signals
R2, G2, B2 and the extracted white component signal W2 are sampled and held in the
D/A conversion units 30_2C during a second period, and so on.
[0038] All held color input signals Ri, Gi, Bi and the white component signal Wi can be
output to the corresponding D/A converters DAC_R~DAC_W and the corresponding analog
reference voltage circuit at one time. For example, the white component signal W1
is output to analog reference voltage generation circuit 20_1, such that the reference
voltages V0
R~V63
R, V0
G~V63
G, V0
B~V63
B and V0
W~V63
W are output to the D/A converters DAC_R~DAC_W. Accordingly, the D/A converters DAC_R~DAC_W
receive the reference voltages V0
R~V63
R, V0
G~V63
G, V0
B~V63
B and V0
W~V63
W and generate the driving voltage VA1
R~VA1
W according to the three color input signals R1, G1, B1 and W1. Similarly, the D/A
conversion units 30_2C~30_NC generate the driving voltages VA2
R~VAN
R, VA2
G~VAN
G and VA2
B~VAN
B at the same time. Namely, the data driver 100C can output the corresponding voltages
to drive one row of data lines in one time.
[0039] Fig. 9 is a schematic diagram of another embodiment of a system, in this case a display
panel, for providing driving voltages. As shown in Fig. 9, the display device 300
comprises a data driver such as data drvier100A/100B/100C, a pixel array 200 and a
gate driver 210. The pixel array 200 comprises RGBW color pixels arranged in matrix,
a plurality of data lines and a plurality of scan lines. The data driver generates
analog driving voltages to the pixel array 200, and the gate driver 210 provides scan
signals to the pixel array 200 such that the scan lines are asserted or de-asserted.
The pixel array 200 generates color images according to the analog driving voltages
from the data driver. While the display panel can be an organic light emitting panel,
an electroluminescent panel or a liquid crystal display panel for example, various
other technologies can be used in other embodiments.
[0040] Fig. 10 schematically shows an embodiment of yet another system, in this case an
electronic device for providing driving voltages. In particular, electronic device
600 employs a display panel such as display panel 600 shown in Fig. 9. The electronic
device 600 may be a device such as a PDA, notebook computer, digital camera, tablet
computer, cellular phone or a display monitor device, for example.
[0041] Generally, the electronic device 600 comprises a housing 500, a display panel 300
and a DC/DC converter 400, although it is to be understood that various other components
can be included, such components not shown or described here for ease of illustration
and description. In operation, the DC/DC converter 400 powers the display panel 300
so that the display panel 300 can display color images.
1. A system for displaying images according to a red (Ri), green (Gi) and blue (Bi) input
signal, the system comprising:
a display panel (300) comprising red, green and blue sub-pixels adapted to generate
color images according to driving voltages;
the display panel further comprising a data driver (100) comprising:
a reference voltage generation circuit (20) adapted to provide sets of reference voltages
suitable for the sub-pixels, wherein the reference voltage generation circuit (20)
at least comprises first, second and third voltage generators (22R, 22G, 22B); and
a digital-to-analog (D/A) conversion unit (30_1A) adapted to generate the driving
voltages to drive the sub-pixels according to the input signals (Ri, Gi, Bi) and the
sets of reference voltages;
characterized in that
the display panel further comprises white sub-pixels;
the data driver further comprises a white component extraction unit (10) adapted to
execute an AND logic operation to the red, green and blue input signals (Ri, Gi, Bi)
controlling brightness of the red, green and blue sub-pixels respectively, to extract
a white component signal (Wi) controlling brightness of a white sub-pixel;
the reference voltage generation circuit (20) is adapted to provide first to third
sets of reference voltages (V0R - V63R , V0G - V63G, V0B - V63B) respectively suitable for the red, green blue and sub-pixels according to the white
component signal (Wi), wherein the first, second and third voltage generators (22R,
22G, 22B), respectively providing the first to third sets of reference voltages, each
comprise:
first and second resistor strings (231, 232; 233, 234; 235, 236) connected to each
other in series, each comprising a plurality of resistors (R0R - R62R; R0G - R62G;
ROB - R62B) and nodes (N4 - N5; N0 - N3);
a first de-multiplexer (211; 213; 215) adapted to selectively make connections between
a first power voltage (VrefH) and one of the nodes of the first resistor string (231; 233; 235) according to the
white component signal; and
a second de-multiplexer (212; 214; 216) adapted to selectively make connections between
a second power voltage (VrefL) and one of the nodes of the second resistor string (232; 234; 236) according to
the white component signal;
wherein the digital-to-analog (D/A) conversion unit (30) is adapted to generate the
driving voltages (VANR, VANG, VANB, VANW) to drive the red, green, blue and white sub-pixels according to the first to fourth
sets of reference voltages, the red, green and blue input signals and the white component
signal; and
wherein the reference voltage generation circuit (20) further comprises a fourth voltage
generator (22W) that is adapted to generate the fourth set of reference voltages suitable
for the white sub-pixels.
2. The system as claimed in claim 1, wherein the driving voltages at least comprise a
red driving voltage (VAN
R), a green driving voltage (VAN
G), a blue driving voltage (VAN
B) and a white driving voltage (VAN
W), and the digital-to-analog conversion unit (30_1) comprises:
a first digital-to-analog converter (DAC_R) adapted to generate the red driving voltage
according to the first set of reference voltages and the red input signal;
a second digital-to-analog converter (DAC_G) adapted to generate the green driving
voltage according to the second set of reference voltages and the green input signal;
a third digital-to-analog converter (DAC_B) adapted to generate the blue driving voltage
according to the third set of reference voltages and the blue input signal, and
a fourth digital-to-analog converter (DAC_W) adapted to generate the white driving
voltage according to the fourth set of reference voltages and the white component
signal.
3. The system as claimed in claim 2, wherein the digital-to-analog conversion unit (30_1)
further comprises a plurality of digital holding units (H/L) connected to the inputs
of the digital-to-analog converters (DAC_R - DAC_W) and adapted to hold the red, green
and blue input signals and the white component signal.
4. The system as claimed in claim 2, wherein the digital-to-analog conversion unit (30_1)
further comprises a plurality of analog holding units (S/H) adapted to hold the red,
green, blue and white driving voltages output by the digital-to-analog converters
(DAC_R - DAC_W).
5. The system as claimed in claim 1, wherein the fourth voltage generator (22W) comprises
a third resistor string (237) connected between the first power voltage and the second
power voltage.
6. The system as claimed in claim 1, wherein the display panel (300) is a liquid crystal
display panel.
7. The system as claimed in claim 1, wherein the display panel (300) is an electroluminescent
panel.
8. The system as claimed in claim 1, wherein the display panel (300) is an organic light
emitting panel.
9. The system as claimed in claim 1, wherein the system is implemented as a PDA, a display
monitor, a digital camera, a notebook computer, a tablet computer or a cellular phone.
10. A method of displaying images according to a red (Ri), green (Gi) and blue (Bi) input
signal, comprising:
generating first to third sets of reference voltages suitable for red, green and blue
sub-pixels, respectively;
generating driving voltages to drive the red, green, and blue sub-pixel according
to the input signals (Ri, Gi, Bi) and the sets of reference voltages; and
displaying color images by driving the sub-pixels according to the driving voltages;
characterized by the steps of:
extracting a white component (Wi) controlling brightness of a white sub-pixel by executing
an AND logic operation to the red, green and blue input signals (Ri, Gi, Bi) controlling
brightness of the red, green and blue sub-pixels respectively ;
generating the first to third sets of reference voltages (V0R - V63R, V0G - V63G , V0B- V63B) respectively suitable for the red, green and blue sub-pixels according to the white
component signal (Wi);
generating a fourth set of reference voltages (V0W - V63W) suitable for the white sub-pixels; and
generating the driving voltages (VANR. VANG , VANB , VANW) to drive the red, green, blue and white sub-pixels according to the first to fourth
sets of reference voltages, the red, green and blue input signals and the white component
signal.
11. The method as claimed in claim 10, wherein the driving voltages at least comprise
a red driving voltage generated according to the first set of reference
voltages and the red input signal, a green driving voltage generated according to
the second set of reference voltages and the green input signal, a blue driving voltage
generated according to the third set of reference voltages and the blue input signal
and a white driving voltage generated according to the fourth set of reference voltages
and the white component signal.
12. The method as claimed in claim 10, further comprising holding the white component
signal (Wi) and the red, green and blue input signals (Ri, Gi, Bi) before generating
the driving voltages.
13. The method as claimed in claim 10, wherein the white component signal (Wi) and the
red, green and blue input signals (Ri, Gi, Bi) each is a digital data comprising N
bits.
14. The method as claimed in claim 10, wherein the white component signal (Wi) and the
red, green and blue input signals (Ri, Gi, Bi) each is a digital data comprising N
bits, and the white component signal (Wi) is obtained by executing the AND logic operation
to M bits of the red, green and blue input signals (Ri, Gi, Bi), and 0 < M < N.
15. The method as claimed in claim 10, further comprising holding the generated driving
voltages.
16. The method as claimed in claim 10, wherein the system comprises a display device and
the display device is an organic light emitting device, a liquid crystal display device
or an electroluminescent device.
1. System zur Anzeige von Bildern gemäß einem roten (Ri), grünen (Gi) und blauen (Bi)
Eingaugs-Signal, wobei das System aufweist:
eine Anzeige-Tafel (300) umfassend rote, grüne und blaue Sub-Pixel, die beschaffen
sind, Farb-Bilder gemäß Treiber-Spannungen zu erzeugen;
wobei die Anzeige-Tafel ferner einen Daten-Treiber (100) aufweist, der umfasst:
eine Referenz-Spannungs-Erzeugungs-Schaltung (20), die beschaffen ist, Sätze von Referenz-Spannungen
passend für die Sub-Pixel bereitzustellen, wobei die Referenz-Spannungs-Erzeugungs-Schaltung
(20) mindestens erste, zweite und dritte Spannungs-Erzeuger (22R, 22G, 22B) aufweist;
und
eine Digital-Analog (D/A) Wandler-Einheit (30_1A), die beschaffen ist, die Treiber-Spannungen
zu erzeugen, um die Sub-Pixel gemäß der Eingangs-Signale (Ri, Gi, Bi) und der Sätze
von Referenz-Spannungen anzutreiben;
dadurch gekennzeichnet, dass
die Anzeige-Tafel ferner weiße Sub-Pixel aufweist;
der Daten-Treiber ferner eine Weiß-Komponenten-Extraktions-Einheit (10) aufweist,
die beschaffen ist, eine logische UND-Verknüpfung an den roten, grünen und blauen
Eingangs-Signalen (Ri, Gi, Bi) durchzuführen, die die Helligkeit der roten, grünen
und blauen Sub-Pixel steuern, um ein Weiß-Komponenten-Signal (Wi) zu extrahieren,
das die Helligkeit eines weißen Sub-Pixels steuert;
wobei Referenz-Spannung-Erzeugungs-Schaltung (20) beschaffen ist, erste bis dritte
Sätze von Referenz-Spannungen (V0A - V63R, V0G- V63G, V0B - V63B, V0W - V63W) jeweils passend für die roten, grünen, blauen und weißen Sub-Pixel gemäß dem Weiß-Komponenten-Signal
(Wi) bereitzustellen, wobei die ersten, zweiten und dritten Spannungs-Erzeuger (22R,
22G, 22B) jeweils die ersten, zweiten und dritten Sätze von Referenz-Spannungen bereitstellen,
wobei jeder aufweist:
erste und zweite Widerstands-Reihen (231, 232, 233, 234; 235, 236), die miteinander
in Reihe geschaltet sind, wobei jede eine Vielzahl von Widerständen (R0R - R62R; R0G
- R62G; R0B - R62B) und Knoten (N4 - N5 ; N0 - N3) aufweist;
einen ersten Demultiplexer (211; 213; 215), der beschaffen ist, selektiv Verbindungen
zwischen einer ersten Versorgungs-Spannung (VrefH) und einem der Knoten der ersten Widerstands-Reihe (231; 233; 235) gemäß dem Weiß-Komponenten-Signal
herzustellen, und
einen zweiten Demultiplexer (212; 214; 216), der beschaffen ist, selektiv Verbindungen
zwischen einer zweiten Versorgungs-Spannung (VrefL) und einem der Knoten der zweiten Widerstands-Reihe (232; 234; 236) gemäß dem Weiß-Komponenten-Signal
herzustellen;
wobei die Digital-Analog (D/A) Wandler-Einheit (30) beschaffen ist, die Treiber-Spannungen
(VANR, VANG, VANB, VANW) zu erzeugen, um die roten, grünen, blauen und weißen Sub-Pixel gemäß den ersten
bis vierten Sätzen von Referenz-Spannungen, den roten, grünen und blauen Eingangs-Signalen
und dem weißen Komponenten-Signal anzutreiben; und
wobei die Referenz-Spannung-Erzeugungs-Schaltung (20) ferner einen vierten Spannungs-Erzeuger
(22W) aufweist, der beschaffen ist, den vierten Satz von Referenz-Spannungen passend
für die weißen Sub-Pixel zu erzeugen.
2. System nach Anspruch 1,
dadurch gekennzeichnet, dass die Treiber-Spannungen mindestens eine rote Treiber-Spannung (VAN
R), eine grüne Treiber-Spannung (VAN
G), eine blauen Treiber-Spannung (VAN
B) und eine weiße Treiber-Spannung (VAN
W) umfassen, und wobei die Digital-zu-Analog-Wandler Einheit (30_1) umfasst:
einen ersten Digital-Analog-Wandler (DAC_R), der beschaffen ist, die rote Treiber-Spannung
gemäß dem ersten Satz von Referenz-Spannungen und dem roten Eingangs-Signal zu erzeugen;
einen zweiten Digital-Analog-Wandler (DAC_G), der beschaffen ist, die grüne Treiber-Spannung
gemäß dem zweiten Satz von Referenz-Spannungen und dem grünen Eingangs-Signal zu erzeugen;
einen dritten Digital-Analog-Wandler (DAC_B), der beschaffen ist, die blaue Treiber-Spannung
gemäß dem dritten Satz von Referenz-Spannungen und dem blauen Eingangs-Signal zu erzeugen,
und
einen vierten Digital-Analog-Wandler (DAC_W), der beschaffen ist, die weiße Treiber-Spannung
gemäß dem vierten Satz von Referenz-Spannungen und dem Weiß-Komponenten-Signal zu
erzeugen.
3. System nach Anspruch 2, wobei die Digital-Analog-Wandler-Einheit (30_1) ferner eine
Vielzahl von digitalen Halte-Einheiten (H/L) aufweist, die mit den Eingängen der Digital-Analog-Wandler
(DAC_R - DAC_W) verbunden sind und beschaffen sind, die roten, grünen, blauen Eingangs-Signale
und das Weiß-Komponenten-Signal zu halten.
4. System nach Anspruch 2, wobei die Digital-Analog-Wandlung Einheit (30_1) ferner eine
Vielzahl von analogen Halte-Einheiten (S/H) aufweist, die beschaffen sind, die roten,
grünen, blauen und weißen Treiber-Spannungen zu halten, die von den Digital-zu-Analog-Wandlern
(DAC_R - DAC_W) ausgegeben werden.
5. System nach Anspruch 1, wobei der vierte Spannungs-Erzeuger (22W) eine dritte Widerstands-Reihe
(237) aufweist, die zwischen der ersten Versorgungs-Spannung und der zweiten Versorgungs-Spannung
geschaltet ist.
6. System nach Anspruch 1, wobei die Anzeige-Tafel (300) eine Flüssigkristall-Anzeige-Tafel
ist.
7. System nach Anspruch 1, wobei die Anzeige-Tafel (300) eine Elektrolumineszenz-Tafel
ist.
8. System nach Anspruch 1, wobei die Anzeige-Tafel (300) eine Organische Licht-emittierende
Tafel ist.
9. System nach Anspruch 1, wobei das System als ein PDA, ein Anzeige-Monitor, eine Digital-Kamera,
ein Notebook, ein Tablet-Computer oder ein Mobiltelefon ausgebildet ist.
10. Verfahren zur Anzeige von Bildern gemäß einem roten (Ri), grünen (Gi) und blauen (Bi)
Eingangs-Signal, umfassend:
Erzeugen erster bis dritter Sätze von Referenz-Spannungen jeweils für rote, grüne
und blaue Sub-Pixel;
Erzeugen von Treiber-Spannungen, um die roten, grünen und blauen Sub-Pixel gemäß den
Eingangs-Signalen (Ri, Gi, Bi) und den Sätzen von Referenz-Spannungen anzutreiben;
und
Anzeigen von Farb-Bildern durch Antreiben der Sub-Pixel gemäß den Treiber-Spannungen;
gekennzeichnet durch die Schritte:
Extrahieren einer Weiß-Komponente (Wi), die die Helligkeit eines weißen Sub-Pixels
steuert durch das Ausführen einer logischen UND-Verknüpfung an den roten, grünen und blauen Eingangs-Signalen
(Ri, Gi, Bi), die jeweils die Helligkeit der roten, grünen und blauen Sub-Pixel steuern;
Erzeugen der ersten bis dritten Sätze von Referenz-Spannungen (VOR - V63R, V0G - V63G, V0B - V63B) jeweils passend für die roten, grünen und blauen Sub-Pixel gemäß dem Weiß-Komponenten-Signal
(Wi);
Erzeugen eines vierten Satzes von Referenz-Spannungen (V0W - V63W) passend für die weißen Sub-Pixel, und
Erzeugen der Treiber-Spannungen (VANR, VANG, VANB, VANW), um die roten, grünen, blauen und weißen Sub-Pixel gemäß den ersten bis vierten
Sätzen von Referenz-Spannungen, den roten, grünen und blauen Eingangs-Signale und
dem Weiß-Komponenten-Signal anzutreiben.
11. Verfahren nach Anspruch 10, wobei die Treiber-Spannungen zumindest eine rote Treiber-Spannung
umfassen, die gemäß dem ersten Satz von Referenz-Spannungen und dem roten Eingangs-Signal
erzeugt wird, eine grüne Treiber-Spannung umfassen, die gemäß dem zweiten Satz von
Referenz-Spannungen und dem grünen Eingangs-Signal erzeugt wird, eine blaue Treiber-Spannung
umfassen, die gemäß dem dritten Satz von Referenz-Spannungen und dem blauen Eingangs-Signal
erzeugt wird, und eine weiße Treiber-Spannung umfassen, die gemäß dem vierten Satz
von Referenz-Spannungen und dem Weiß-Komponenten-Signal erzeugt wird.
12. Verfahren nach Anspruch 10 ferner aufweisend ein Halten der Weiß-Komponenten-Signals
(Wi) und der roten, grünen und blauen Eingangs-Signale (Ri, Gi, Bi) vor dem Erzeugen
der Treiber-Spannungen.
13. Verfahren nach Anspruch 10, wobei das Weiß-Komponenten-Signal (Wi) und die roten,
grünen und blauen Eingangs-Signale (Ri, Gi, Bi) jeweils einem digitalen Datenwert
mit N Bit entsprechen.
14. Verfahren nach Anspruch 10, wobei das Weiß-Komponenten-Signal (Wi) und die roten,
grünen und blauen Eingangs-Signale (Ri, Gi, Bi) jeweils einem digitalen Datenwert
mit N Bits entsprechen, und wobei das Weiß-Komponenten-Signal (Wi) gewonnen wird durch
die Durchführung der UND- Verknüpfung an M Bits der roten, grünen und blauen Eingangs-Signale
(Ri, Gi, Bi), und 0 <M <N ist.
15. Verfahren nach Anspruch 10 ferner aufweisend ein Halten der erzeugten Treiber-Spannungen.
16. Verfahren nach Anspruch 10, wobei das System eine Anzeige-Vorrichtung aufweist, und
die Anzeige-Vorrichtung eine Organische Licht-emittierende Vorrichtung, eine Flüssigkristall-Anzeige-Tafel-Vorrichtung
oder ein Elektrolumineszenz-Vorrichtung ist.
1. Un système pour l'affichage d'images suivant un signal d'entrée rouge (Ri), vert (Gi)
et bleu (Bi), le système comprenant:
un panneau d'affichage (300) comportant des sous-pixels rouges, verts et bleus adaptés
à la génération d'images en couleur en fonction de tensions de commande ;
le panneau d'affichage comportant en outre un pilote de données (100) comprenant :
un circuit de génération de tensions de référence (20) adapté pour générer des jeux
de tensions de référence convenant aux sous-pixels, dans lequel le circuit de génération
de tensions de référence (20) comporte au moins un premier, un second et un troisième
générateurs de tension (22R, 22G, 22B); et
une unité (30_1A) de conversion numérique-analogique (D/A) adaptée à la génération
de tensions de commande pour la commande des sous-pixels en fonction des signaux d'entrée
(Ri, Gi, Bi) et des jeux de tension de référence ;
caractérisé en ce que
le panneau d'affichage comporte en outre des sous-pixels blancs;
le pilote de donnée comporte en outre une unité d'extraction de composante blanche
(10) adaptée pour l'exécution d'une opération logique ET aux signaux d'entrée rouge,
vert et bleu (Ri, Gi, Bi) commandant la luminosité des sous-pixels rouges, verts et
bleus respectivement, pour l'extraction d'un signal de composante blanche (Wi) commandant
la luminosité d'un sous-pixel blanc ;
le circuit de génération de tension de référence (20) est adapté pour la génération
des premier au troisième jeux de tension de référence (V0R-V63R, V0G-V63G, V0B-V63B) respectivement adaptés aux sous-pixels rouges, verts et bleus en fonction du signal
de composante blanche (Wi), dans lequel les premier, second et troisième générateurs
de tension (22R, 22G, 22B) génèrent respectivement les premier, second et troisième
jeux de tension de référence, chacun comportant :
des premières et secondes chaînes de résistances (231, 232 ; 233, 234 ; 235, 236)
connectées en série les unes aux autres, chacune comportant une pluralité de résistances
(R0R-R62R ; R0G-R62G ; ROB-R62B) et des noeuds (N4-N5 ; N0-N3) un premier dé-multiplexeur
(211 ; 213 ; 215) adapté pour des connexions sélectives entre une première tension
d'alimentation (VrefH) et l'un des noeuds de la première chaîne de résistance (231
; 233 ; 235) en fonction du signal de composante blanche ;
et
un second dé-multiplexeur (212 ; 214 ; 216) adapté pour des connexions sélectives
entre une seconde tension d'alimentation (VrefL) et l'un des noeuds de la seconde
chaîne de résistance (232 ; 234 ; 236) en fonction du signal de composante blanche
;
dans lequel l'unité (30) de conversion numérique-analogique (D/A) est adaptée à la
génération des tensions de commande (VANR, VANG, VANB, VANW) pour commander les sous-pixels rouges, verts , bleus et blancs en fonction des premier
au quatrième jeux de tension de référence, des signaux d'entrée rouge, vert et bleu
et du signal de composante blanche ; et
dans lequel le circuit de génération de tension de référence (20) comporte en outre
un quatrième générateur de tension (22W) adapté à la génération du quatrième jeu de
tension de référence convenant aux sous-pixels blancs.
2. Le système tel que revendiqué dans la revendication 1, dans lequel les tensions de
commande comportent au moins une tension de commande pour le rouge (VAN
R), une tension de commande pour le vert (VAN
G), une tension de commande pour le bleu (VAN
B) et une tension de commande pour le blanc (VAN
W), et l'unité (30_1A) de conversion numérique-analogique comporte :
un premier convertisseur numérique analogique (DAC_R) adapté pour la génération de
la tension de commande pour le rouge en fonction du premier jeu de tensions de référence
et du signal d'entrée rouge ;
un second convertisseur numérique analogique (DAC_G) adapté pour la génération de
la tension de commande pour le vert en fonction du second jeu de tensions de référence
et du signal d'entrée vert ;
un troisième convertisseur numérique analogique (DAC_B) adapté pour la génération
de la tension de commande pour le bleu en fonction du troisième jeu de tensions de
référence et du signal d'entrée bleu;
un quatrième convertisseur numérique analogique (DAC_W) adapté pour la génération
de la tension de commande pour le blanc en fonction du quatrième jeu de tensions de
référence et du signal de composante blanche.
3. Le système tel que revendiqué dans la revendication 2, dans lequel l'unité (30_1A)
de conversion numérique-analogique comporte en outre une pluralité d'unités d'échantillonnage
numériques (H/L) connectées aux entrées des convertisseurs numériques-analogiques
(DAC_R - DAC_W) et adaptées à l'échantillonnage des signaux d'entrées rouge, vert
et bleu et du signal de composante blanche.
4. Le système tel que revendiqué dans la revendication 2, dans lequel l'unité (30_1A)
de conversion numérique-analogique comporte en outre une pluralité d'unités d'échantillonnage
analogiques (S/H) et adaptées pour l'échantillonnage des tensions de commande pour
le rouge, le vert, le bleu et le blanc générés par les convertisseurs numériques-analogiques
(DAC_R - DAC_W).
5. Le système tel que revendiqué dans la revendication 1, dans lequel le quatrième générateur
de tension (22W) comporte une troisième chaîne de résistance (237) connectée entre
la première tension d'alimentation et la seconde tension d'alimentation.
6. Le système tel que revendiqué dans la revendication 1, dans lequel le panneau d'affichage
(300) est un panneau d'affichage à cristaux liquides.
7. Le système tel que revendiqué dans la revendication 1, dans lequel le panneau d'affichage
(300) est un panneau électroluminescent.
8. Le système tel que revendiqué dans la revendication 1, dans lequel le panneau d'affichage
(300) est un panneau électroluminescent organique.
9. Le système tel que revendiqué dans la revendication 1, dans lequel le système est
implémenté sous la forme d'un assistant numérique portable (PDA), d'un moniteur d'affichage,
d'un appareil photographique numérique, d'un ordinateur portable, d'une tablette numérique
; ou d'un téléphone cellulaire.
10. Une méthode d'affichage d'images suivant un signal d'entrée rouge (Ri), vert (Gi)
et bleu (Bi), comprenant :
la génération d'une première, seconde et troisième tensions de référence adaptés aux
sous-pixels rouges, verts et bleus, respectivement ;
la génération de tensions de commande pour la commande des sous-pixels rouges, verts,
et bleus en fonction des signaux d'entrée (Ri, Gi, Bi) et des jeux de tensions de
référence ; et
l'affichage d'images en couleur par la commande de sous-pixels en fonction des tensions
de commande ;
caractérisée par les étapes :
l'extraction d'une composante blanche (Wi) commandant la luminosité d'un sous-pixel
blanc au moyen de l'exécution d'une opération ET logique sur les signaux d'entrées
rouge, vert et bleu (Ri, Gi, Bi) commandant la luminosité des sous-pixels rouge, vert
et bleu respectivement ;
la génération des premier, second et troisième jeux de tensions de référence (V0R-V63R, V0G-V63G, VGB-V63B) respectivement adaptés aux sous-pixels rouge, vert et bleu en fonction du signal
de composante blanche (Wi) ;
la génération d'un quatrième jeu de tensions de référence (V0W-V63W) convenant aux sous-pixels blancs ; et
la génération des tensions de commande (VANR, VANG, VANB, VANW) pour commander les sous-pixels rouges, verts , bleus et blancs en fonction des premier
au quatrième jeux de tension de référence, des signaux d'entrée rouge, vert et bleu
et du signal de composante blanche.
11. La méthode telle que revendiquée dans la revendication 10, dans laquelle les tensions
de commande comportent au moins une tension de commande pour le rouge générée en fonction
du premier jeu de tensions de référence et du signal d'entrée pour le rouge, une tension
de commande pour le vert générée en fonction du second jeu de tensions de référence
et du signal d'entrée vert, une tension de commande pour le bleu générée en fonction
du troisième jeu de tensions de référence et du signal d'entrée bleu et une tension
de commande pour le blanc générée en fonction du quatrième jeu de tensions de référence
et du signal de composante blanche.
12. La méthode telle que revendiquée dans la revendication 10, comportant en outre l'échantillonnage
du signal de composante blanche (Wi) et des signaux d'entrée rouge, vert et bleu (Ri,
Gi, Bi) avant la génération des tensions de commande.
13. La méthode telle que revendiquée dans la revendication 10, dans laquelle le signal
de composante blanche (Wi) et les signaux d'entrée rouge, vert et bleu (Ri, Gi, Bi)
se composent d'une donnée numérique comprenant N bits.
14. La méthode telle que revendiquée dans la revendication 10, dans laquelle le signal
de composante blanche (Wi) et les signaux d'entrée rouge, vert et bleu (Ri, Gi, Bi)
se composent chacun d'une donnée numérique sur N bits, et le signal de composante
blanche (Wi) est obtenu au moyen d'une opération logique ET sur M bits des signaux
d'entrée rouge, vert et bleu (Ri, Gi, Bi), et 0 < M < N.
15. La méthode telle que revendiquée dans la revendication 10, comportant en outre l'échantillonnage
des tensions de commande générées.
16. la méthode telle que revendiquée dans la revendication 10, dans lequel le système
comporte un système d'affichage, et le système d'affichage est un dispositif électroluminescent
organique, un dispositif d'affichage à cristaux liquides ou un dispositif électroluminescent.