JPH036987A - Color tone correction circuit for color display device - Google Patents

Abstract

PURPOSE:To correct the color tone of a display picture freely by selecting and setting an optional correction level among predetermined several stages of correction levels in a luminance data correction circuit and correcting the luminance data of each primary color (3 primary colors) being an original display data. CONSTITUTION:A luminance data correction circuit 2 consists of 3 correction circuits 2R, 2G, 2B. The correction circuits 2R, 2Q, 2B convert the inputted 3-bit of luminance data into a 4-bit luminance data. A gradation control circuit 4 consists of 3 gradation control signal generating circuits 4R,4G and 4B and one data arrangement circuit 4C. Then the generating circuits 4R, 4G and 4B receive luminance data from the circuits 2R, 2G and 2B respectively and generate a gradation among 18 stages. The data arrangement circuit 4C arranges the gradation control signal outputted from the circuits 4R, 4G and 4B into one block of signal group and gives the result as a final display data LD to a color liquid crystal display device 6.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color tone correction circuit for a color display device such as a color liquid crystal display device.

BACKGROUND OF THE INVENTION In the case of a conventional color liquid crystal display device, the color tone of the display screen is determined by the spectral characteristics of the color filter, the light emission characteristics of the backlight source, the spectral characteristics of the reflector, the spectral characteristics of the diffuser, etc. On the other hand, the optical characteristics of each component are determined by their manufacturing conditions. Therefore, the color tone of the color liquid crystal display device is uniformly determined by the manufacturing conditions of each of the constituent members.

Therefore, in conventional color liquid crystal display devices, so that the white color displayed on the display screen is the standard white color,
Manufacturing conditions for color filters, backlight sources, reflectors, diffusers, etc. are strictly defined.

Problems to be Solved by the Invention However, even if the manufacturing conditions for backlight sources, reflectors, color filters, etc. are strictly determined at the manufacturing stage, as in the case of the color liquid crystal display device described above, the optical characteristics of these components may change over time. If such a change occurs, the color tone of the display screen changes and there is a problem in that it is no longer possible to display the standard white color as at the time of manufacture.

Furthermore, even if the user wanted to change the color tone of the display screen according to his/her preference, there was no way to change the color tone of the color liquid crystal display device.

Therefore, an object of the present invention is to provide a color tone correction circuit for a color display device that can freely correct the tone of the display screen of the color display device.

Means for Solving the Problems The present invention processes the luminance data of each of the three primary colors, which is output from a display data generator in association with each pigment of a color display device, at several predetermined correction levels. A brightness data correction circuit that corrects and outputs one correction level that can be freely selected; and a level that controls the brightness of each pixel of the color display device according to the brightness data output from the brightness data correction circuit.* Ill
This is a color tone correction circuit for a color display device, characterized by comprising a tone control circuit that outputs a control signal.

According to the present invention, when an arbitrary correction level is selected and set from among several predetermined correction levels in the luminance data correction circuit, the three primary colors that are the original display data output from the display data generator are The brightness data for each primary color is corrected by the above correction level in the brightness data correction circuit. Using this corrected luminance data as final display data, the gradation control circuit controls the luminance of each pixel of the color display device to a luminance according to the final display data. Therefore, the color tone of the display screen of the color display device is corrected to a color tone different from the color tone based on the original display data.

Embodiment FIG. 1 is a block diagram showing a schematic configuration of a color display system using a color tone correction circuit A according to an embodiment of the present invention.

In FIG. 1, a display data generating device 1 is a device that outputs display data corresponding to each pixel of a color liquid crystal display device 5, and the display data includes luminance data for each of the three primary colors of red, green, and blue. In other words, 3-bit luminance data rs is used as display data regarding red color.
R2, SR1°5ROJ is the same 3-bit display data between green f) Luminance data rSG2. SGI,
SGO" is the same 3-bit luminance data rSB2.SGO" as the display data regarding blue color. SBI and 5BOJ are output respectively.

A luminance data correction circuit 2 for correcting the luminance data for each color outputted from the display data generation device 1 is provided at the next stage of the display data generation device 1. This luminance data correction circuit 2 consists of three correction circuits 2R, 2G, and 2B, and the first correction circuit 2R collects the red luminance data rSR2, SRI, and 5RO output from the display data generator 1.
The second correction circuit 2G is used to correct green luminance data rSG2.J. Used for SGI, 5GOJ correction,
The third correction circuit 2B uses blue luminance data "SB2.SB
Used for correction of I, 5BOJ.

Each of these correction circuits 2R, 2G, and 2B has a function of converting the input 3-bit luminance data into 4-bit luminance data. In other words, the red correction circuit 2R converts the input luminance data rsR2, SRI , 5ROJ 4
Bit brightness data “MR3, M R2, M R1,
M
1, SGIJ is also 4-bit luminance data rMG3. The blue correction circuit 2B converts the input luminance data rsB2, 5BISBO, into 4-bit luminance data rM83M B 2 , M B 1 , M
Convert to B OJ and output.

The correction selection switch group 3 is the correction circuit 2R22G, 2B.
The first switch 3R is connected between the red correction circuit 2R and the ground, and the second switch 3G is connected to the green correction circuit. Connected between 2G and ground,
The third switch 3B is connected between the blue correction circuit 2B and ground.

The next stage of the luminance data correction circuit 2 includes each correction circuit 2R.
. This 61-gradation circuit 4 includes three gradation control signal generation circuits 4R.

Consisting of 4G, 4B and one data alignment circuit 4C,
The first gradation control signal generation circuit 4R is a red correction circuit 2R.
Luminance data from rMR3, MR2゜MRI, MROJ
The second gradation control signal generation circuit 4G inputs the luminance data rMG3 from the green correction circuit 2G and generates a gradation control signal for displaying the corresponding one of the 16 gradations.
．． Input MG2゜MG 1, MG OJ,
The third gradation control signal generation circuit 4B generates a gradation control signal that displays the corresponding first gradation among the 16 levels, and the third gradation control signal generation circuit 4B receives the luminance data r M B 3 from the blue color correction circuit 2B.
, MB2, MBI, and MBOJ are input to generate a gradation control signal that displays one corresponding gradation among 16 levels. When the color liquid crystal display device 5 requires an analog input for its N controller, a pulse amplitude modulation signal is adopted as the gradation control signal, and the P
In the case of digital input and color liquid crystal display device 5 that requires J key sub-control, the above-mentioned 11 regulation (No. 13 of frame interrogation method or pulse amplitude modulation method is used as wholesale signal) The data alignment circuit 4C arranges the gradation control signals outputted from each gradation control signal generation circuit 4R, 4G, and 4B into one block of signal groups, and sends them to the color liquid crystal display device 5 as final display data LD. Note that a synchronizing signal S is provided from the display data generator 1 to the luminance data correction circuit 2, gradation control circuit 4, and color liquid crystal display device 5 to control their operation timings.

The luminance data output from each correction circuit 2R, 2G, 2B and correspondingly each gradation υ control signal generation circuit 4R,
Table 1 shows the relationship between the gradation control signals generated in 4G and 4B. However, in Table 1, each correction circuit 2R, 2
MXO, MXi, MX2 . It is shown as MX3.

(The following is a margin) Table 1. FIG. 2 is a block diagram showing a specific configuration of the correction circuits 2R, 2G, and 2B that constitute the luminance data correction circuit 2 described above.

Since the configuration of 2B is the same, here, each correction circuit 2
The configuration of the correction circuit 2Y in which R, 2G, and 2B are shared will be described. This correction circuit 2Y includes a full adder 20, pull-up resistors 21, 22 . OR”l-t23 and AND
11rlj by gate 24.

The full adder 20 has its input terminals A3°A2 .
The 4-bit augend input from Al, AO and another input terminal B3. B2. Addition is performed with the 4-bit addition number input from Bl and BO, and the result is sent to output terminal Σ3.
．． Σ2. Σ1. It has the function of outputting from ΣO, and its input terminal A3. A2°A1 contains 3-bit luminance data rSX2.A1 from the display data generator 1. SXI, 5XOJ
(For example, the correction circuit 2Y inputs the red luminance data rsR2, SRI, SRO to the red correction circuit 2R).The input terminal AO is connected to the power supply terminal cc, and the other input terminals B3.B2.Bl, BO are connected to the power supply terminal cc via a pull-up resistor 22, and are also connected to ground via a switch 3Y. It is one switch of the correction selection switch group 3 described above, and corresponds to the switch 3R when the correction circuit 2Y is, for example, a red correction circuit 2R.Furthermore, the three input terminals A
3. A2. Luminance data rsx2, SX input to Al
I, 5XOJ are also given to OR gate 23 as the three outputs, and the output of OR gate 23 is the
It is given as human power. Another one of this AND gate 24
The human power is applied from the output terminal Σ0 of the full adder 20. Then, the output MXO of the AND gate 24 and the other three output terminals Σ3. Σ2. Output MX3 from Σ1. MX2°MXI is taken out as the output of the correction circuit 2Y.

That is, this correction circuit 2Y is, for example, a red correction circuit 2.
The i% group of H has its output rMX3. MX2MX1. M
XOJ is rMR3, MR2, MRI.

Corresponds to MRO.

Table 2 shows the luminance data 9 input to the correction circuit 2Y.
rSX2. SXI, 5XIJ and correction circuit 2Y when switch 3Y is off and when switch 3Y is on
The output rMX3. MX2. MX1, MXO".

Table 2 Next, the operation of the color display system described above will be explained.

For example, three switches 3R of correction selection switch group 3
, 3G, 3B are all set to off, the second
In the figure, input terminal B3. The input signal of B2゜Bl, BO is rH,H,)(,H,, and the input terminal AO
The input signal becomes H regardless of whether the switch 3Y is on or off. Therefore, input terminal A3. A2. Assuming that luminance data rSX2°SXI, 5XOJ is input to At, input terminals A3. A2. A1. AO has rsX2. as the augend. SXI, SXO, H, and other input terminals B3. B2. The addition number 'H, H, H, HJ (complement of 'L, L, LH') is input to Bl and BO, and the output terminal Σ3. Σ, 2゜Σ1. From ΣO, FSX2. SXI.

SXO and LJ are output. Since the output of the output terminal Σ0 is at L at this time, the output of the AND gate 24 becomes MXO. That is, the output rM of the correction circuit 2Y at this time
X3. MX2. MXI, MXO" is data whose upper three bits are luminance data rsX2°SXI, 5XOJ, and whose least significant bit is L. That is, the luminance data output from each of the correction circuits 2R12G and 2B has the values shown in the right column of Table 2 relative to the luminance data output from display data generation device 1 (left column of Table 2).

These luminance data outputted from each correction circuit 2R, 2G, 2B are converted to the gradation level corresponding to the luminance data by the corresponding gradation control signal generation circuits 4R, 4G, 4B of the next stage gradation control circuit 4. These gradation control signals are arranged into one block of signal groups by the data alignment circuit 40 at the next stage, and the final display data LD
The image is sent to the color liquid crystal display device 5, and at this time, the color liquid crystal display device 5 displays a standard color tone.

On the other hand, the three switches 3R, 3 of the correction selection switch group 3
Among G and 3B, for example, only switch 3R is set to on, and the other two switches 3G.

3B is set to OFF, the red color correction circuit 2R has input terminals B3°B2.B2.3B in FIG. Bl,
The addition numbers input to BO are rL,L.

It becomes L, LJ. As mentioned earlier, the input signal of the input terminal AO is 1-(regardless of whether the switch 3R is on or off), so the augend input to the input terminals A3.A2.Al and AO is rSX2.SX1,5XO9H. At this time, the output terminal Σ3.Σ2Σ1.Σ0 outputs rSX2.SXI as an added value.

SXO and HJ are output. Input terminal A3. A2゜A1
Luminance data input to rsX2. SXI.

When 5XOJ is rL, L, L, the output of the OR gate 23 becomes L, and the output MXO of the AND gate 24 becomes L, but in other cases, the output of the OR gate 23 becomes ■]
Therefore, the output MXO of the AND gate 24 is H
becomes. That is, the output rM of the correction circuit 2Y at this time
X3. MX2. MXi and MXOJ convert the upper 3 bits into luminance data rsX2. SXI, 5XOJ, and the least significant bit thereof is H<luminance data rSX2. SXI, 5XOJ
is the data except for rL, L, and LJ).

In other words, the luminance data output from the correction circuit 2R at this time becomes the value shown in the center column of Table 2 with respect to the luminance data output from the display data generator 1 (left l!l of Table 2). The luminance data output from the other two correction circuits 2G and 2B have the values shown in the right column of Table 2. In Table 2, for the same luminance data in the left column, the center capture value is one step higher in severity level than the value in the right column by the change in the least significant bit, and the luminance data rMR3° M.R.
2. Red adjustable selected by M R1, M ROJ, other brightness data' M G 3 M 02MG
I, MGO'', 'MB3. MB2. M.B.I.

Selected by MBOJ. The gradation is one step brighter than the gradation of green or blue. As a result, among the luminance data of each color output as the same gradation from the display data generator 1, only the red luminance data is corrected to a brighter gradation, so that on the screen of the color liquid crystal display 5, red is Displayed with emphasis. Note that the output rMX3. of the correction circuit 2Y shown in Table 2. MX2. Among MXI and MXOJ, there is no value corresponding to the 1/15th gradation shown in Table 1, so the 1/15th gradation is not displayed in this embodiment.

Similarly, if you want to emphasize only green, turn on only switch 3G of correction selection switch group 3, and if you want to emphasize only blue, turn on only switch 3B, and turn on the other switches. Just set it to off.

In addition, all the switches 3R of the correction selection switch group 3,
When 3G and 3B are set to on, all three primary colors become brighter than when all switches 3R, 3G, and 3B are set to off, making it possible to brighten the overall color tone of the screen.

Effects of the Invention As described above, according to the color tone correction circuit of the color display device of the present invention, the luminance data for each of the three primary colors output from the display data generation device is adjusted to several predetermined correction levels. By freely selecting and correcting one of the correction levels, and controlling the brightness of each pixel of the color display device according to the corrected brightness data, the color tone of the screen of the color display device can be adjusted. Not only can it be easily adjusted during the production process, but users of color display devices can also change the color tone to suit their tastes.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a color display system to which a color tone correction circuit according to an embodiment of the present invention is applied, and FIG. 2 is a block diagram showing a specific configuration of a correction circuit in the color tone correction circuit. It is. A...color tone correction circuit, 1...display data generator,
2... Brightness data correction circuit, 2R, 2G, 2B...
Correction circuit, 3... Correction selection switch group, 4... tl
F tone 1liII circuit, 4R, 4G, 4B...gradation control signal generation circuit, 5...color liquid crystal display device

Claims (1)

[Claims] Brightness data for each of the three primary colors output from the display data generator in association with each pigment of the color display device is adjusted to one correction level that can be freely selected from several predetermined correction levels. a luminance data correction circuit that corrects and outputs the luminance data, and a gradation control circuit that outputs a gradation control signal that controls the luminance of each pixel of a color display device according to the luminance data output from the luminance data correction circuit. A color tone correction circuit for a color display device, characterized by comprising: