JP2013101354A - Display drive circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control degree of expanding saturation according to a color gamut of a liquid crystal panel or color characteristics of R, G, and B.SOLUTION: A display drive circuit comprises: an initial color gamut vertex coordinate storage unit (211) capable of storing initial color gamut vertex coordinates; a user target color gamut vertex coordinate storage unit (212) capable of storing user target color gamut vertex coordinates; and a saturation expansion coefficient determination unit (210) for determining an expansion coefficient of saturation data on the basis of the initial color gamut vertex coordinates and the user target color gamut vertex coordinates. Then, the display drive circuit comprises an expansion unit (206) for expanding saturation of the display data on the basis of the expansion coefficient of saturation of display data. The expansion coefficient of the saturation data is determined on the basis of the initial color gamut vertex coordinates and the user target color gamut vertex coordinates, and the saturation of the display data is expanded on the basis of the expansion coefficient, thereby, degree of expanding the saturation can be controlled according to a color gamut of a liquid crystal panel.

Description

  The present invention relates to a display drive circuit capable of driving a liquid crystal panel according to input display data.

  As an example of the display driving circuit, a liquid crystal driving circuit for driving a liquid crystal display can be given. In recent years, small liquid crystal displays are mounted on battery-operated information devices and mobile phones. These small liquid crystal displays are highly demanded of high definition, low cost, and low power. In order to solve these problems, measures are taken such as increasing the passband characteristics of the color filter. As a side effect, the color purity of each primary color of R, G, B, which is a color model in which color information is digitized, is lowered, and as a result, a side effect that a color range (color gamut) that can be expressed as a liquid crystal panel is narrowed occurs. For this reason, small liquid crystal displays tend to have low color expressive power.

  Therefore, an attempt has been made to enhance the color expression within the expressive power of the liquid crystal panel by apparently expanding the color gamut by emphasizing the saturation of data displayed on the liquid crystal display. For example, as in Patent Document 1, a technique for solving color collapse caused by saturation after saturation is known. By applying this technique to a small liquid crystal panel, an apparent color gamut is known. And can improve the color expression within the expression of the panel.

Japanese Patent No. 3749722

  However, according to the study of the present inventor, the characteristics of the color filter and the liquid crystal material used by the liquid crystal panel are different and the color gamut is also different. It is considered that it is difficult to correct the degree of extension of the saturation according to the area of the color gamut of the target liquid crystal panel. Further, since the characteristics of each color of R, G, and B are different even in the same color gamut, it is also possible to correct the degree of extending the saturation according to the color characteristics. It is thought that it is difficult to apply only.

  An object of the present invention is to provide a technique capable of controlling the degree of expansion of saturation according to the color gamut of a liquid crystal panel or the color characteristics of R, G, and B.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  A representative one of the inventions disclosed in the present application will be briefly described as follows.

  That is, the display driving circuit includes an initial color gamut vertex coordinate storage unit capable of storing an initial color gamut vertex coordinate, a user target color gamut vertex coordinate storage unit capable of storing a user target color gamut vertex coordinate, and the initial color gamut vertex A saturation expansion coefficient determination unit that determines the expansion coefficient of the saturation data based on the coordinates and the user target color gamut vertex coordinates; and an expansion unit that expands the saturation of the display data based on the saturation expansion coefficient. including. A saturation coefficient expansion coefficient is determined based on the initial color gamut vertex coordinates and the user target color gamut vertex coordinates, and the saturation of the display data is expanded based on the coefficient. This makes it possible to control the degree of extending the saturation according to the color gamut of the liquid crystal panel.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, in a display driving circuit capable of driving a liquid crystal panel according to input display data, the degree of expansion of saturation can be controlled according to the color gamut of the liquid crystal panel or the color characteristics of R, G, and B. it can.

1 is a block diagram illustrating a configuration example of a liquid crystal driver as an example of a display driving circuit according to the present invention. It is a block diagram of a configuration example of a saturation expansion unit in the liquid crystal driver. It is explanatory drawing of the register value setting in the said saturation expansion | extension part. It is a flowchart of the saturation expansion coefficient calculation in the said saturation expansion part. FIG. 10 is a block diagram illustrating another configuration example of a saturation expansion unit in the liquid crystal driver. It is a flowchart of the saturation expansion coefficient calculation in the structure shown by FIG. FIG. 6 is a block diagram illustrating a configuration example of a saturation expansion coefficient interpolation circuit in FIG. 5. It is explanatory drawing of the saturation expansion coefficient interpolation in the saturation expansion coefficient interpolation circuit in FIG. FIG. 6 is a diagram illustrating the relationship between saturation data and post-expansion saturation data in the saturation expansion coefficient interpolation circuit in FIG. 5. FIG. 10 is a block diagram illustrating another configuration example of a saturation expansion unit in the liquid crystal driver.

1. Representative Embodiment First, an outline of a typical embodiment of the invention disclosed in the present application will be described. The reference numerals of the drawings referred to with parentheses in the outline description of the representative embodiments merely exemplify what are included in the concept of the components to which the reference numerals are attached.

  [1] A display driving circuit (101) according to a typical embodiment of the present invention includes an initial color gamut vertex coordinate storage unit (211) capable of storing an initial color gamut vertex coordinate, and a user target color gamut vertex coordinate. A user target color gamut vertex coordinate storage unit (212) that can be stored, and a saturation expansion coefficient determination unit that determines the expansion coefficient of saturation data based on the initial color gamut vertex coordinates and the user target color gamut vertex coordinates ( 210) and an expansion unit (206) for expanding the saturation of the display data based on the saturation expansion coefficient.

  According to the above configuration, since the expansion coefficient of the saturation data is determined based on the initial color gamut vertex coordinates and the user target color gamut vertex coordinates, and the saturation of the display data is expanded based on the coefficient, The degree of extending the saturation can be controlled according to the color gamut of the liquid crystal panel.

  [2] In the above [1], the saturation expansion coefficient determination unit sets an area ratio between a color gamut calculated from the initial color gamut vertex coordinates and a color gamut calculated from the user target color gamut vertex coordinates. Based on this, the expansion coefficient can be calculated.

  [3] In the above [1], the saturation expansion coefficient determination unit determines an area ratio between a color gamut calculated from the initial color gamut vertex coordinates and a color gamut calculated from the user target color gamut vertex coordinates. The expansion coefficient can be calculated by taking the square root.

  [4] An interface (102) that enables information to be set to the initial color gamut vertex coordinate storage unit and the user target color gamut vertex coordinate storage unit from the outside of the display drive circuit can be provided.

  [5] A display drive circuit (101) according to another embodiment of the present invention stores an initial color gamut vertex coordinate storage unit (211) capable of storing an initial color gamut vertex coordinate and a user target color gamut vertex coordinate. R, G, and B for determining a saturation expansion coefficient for each of R, G, and B based on a possible user target color gamut vertex coordinate storage unit (212) and the initial color gamut vertex coordinates and the user target color gamut vertex coordinates A G / B saturation expansion coefficient determination section (501), a saturation expansion coefficient interpolation section (503) for performing interpolation calculation of the R, G, and B saturation expansion coefficients, and the saturation expansion coefficient interpolation section. A decompression unit (206) for decompressing the saturation of the display data based on the interpolated saturation expansion coefficient.

  According to the above configuration, the saturation expansion coefficients of R, G, and B are determined based on the initial color gamut vertex coordinates and the user target color gamut vertex coordinates, and based on the R, G, B, the saturation expansion coefficients are determined. Since the interpolation calculation of the saturation expansion coefficient for each B is performed, the degree of saturation expansion can be controlled according to the R, G, B color characteristics of the liquid crystal panel.

  [6] In the above [5], the R, G, B saturation expansion coefficient determining unit calculates the distance from the white coordinate in the initial color gamut vertex coordinates and the user target color gamut vertex coordinates for each of R, G, B. It is possible to obtain a value and calculate a saturation expansion coefficient for each of R, G, and B from the ratio.

  [7] In the above [6], the saturation expansion coefficient interpolation unit can be configured to linearly interpolate the R, G, B saturation expansion coefficients based on hue data.

  [8] In the above [5], an interface (102) that enables information setting to the initial color gamut vertex coordinate storage unit and the user target color gamut vertex coordinate storage unit from the outside of the display drive circuit is provided. it can.

  [9] The display drive circuit (101) according to another embodiment of the present invention includes an R, G, B saturation expansion coefficient storage unit (1001) capable of storing R, G, B saturation expansion coefficients. And a saturation expansion coefficient interpolation unit (503) that performs interpolation calculation of the saturation expansion coefficients of R, G, and B, and the saturation expansion coefficient interpolated by the saturation expansion coefficient interpolation unit, An expansion unit (206) for expanding the saturation of the display data.

  According to the above configuration, since the saturation of the display data is expanded based on the saturation expansion coefficient interpolated by the saturation expansion coefficient interpolation unit, the R, G, B color characteristics of the liquid crystal panel can be obtained. Accordingly, the degree of extending the saturation can be controlled.

  [10] In the above [9], the saturation expansion coefficient interpolation unit can be configured to linearly interpolate the R, G, and B saturation expansion coefficients based on hue data.

  [11] In the above [9], an interface (102) capable of setting information to the R, G, B saturation expansion coefficient storage unit from the outside of the display drive circuit can be provided.

2. Next, the embodiment will be described in more detail.

  Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

<Embodiment 1>
FIG. 1 shows a liquid crystal display device including a liquid crystal driver which is an example of a display driving circuit according to the present invention.

  The liquid crystal display device 100 shown in FIG. 1 includes a liquid crystal driver 101, a control processor 113, and a liquid crystal panel 114, although not particularly limited. The liquid crystal driver 101 drives and controls the liquid crystal panel with the liquid crystal driver. The control processor 113 creates display data and transfers it to the liquid crystal driver 101. The liquid crystal panel 114 receives the liquid crystal source signal 110, the liquid crystal gate signal, and the common signal 111 from the liquid crystal driver 101, and performs image display. The backlight module 115 illuminates the liquid crystal panel 114 by turning on the backlight with a desired brightness. Thereby, the display of the liquid crystal panel 114 can be seen as visible light.

  The liquid crystal driver 101 is not particularly limited, but includes a system interface 102, a control register 103, a saturation expansion circuit 104, a graphic RAM (random access memory) 105, a source line drive circuit 108, a timing generation circuit 106, a gradation voltage. A generation circuit 107 and a liquid crystal drive level generation circuit 109 are formed on a single semiconductor substrate such as a single crystal silicon substrate by a known semiconductor integrated circuit manufacturing technique.

  The control register 103 is a set of registers for controlling each part of the liquid crystal driver. The system interface 102 takes in various data including data to be written to the control register 103 from the outside of the liquid crystal driver 101 and supplies it to the internal block. The saturation expansion circuit 104 generates display data obtained by expanding the saturation of the display data from the system interface 102 by a saturation expansion method described later, and transfers the display data to the graphic RAM 105. The graphic RAM 105 serves as a buffer for receiving and storing display data via the saturation expansion circuit 104 and delivering the display data to the source line driver circuit 108. The timing generation circuit 106 generates the operation timing of the entire liquid crystal driver according to the information stored in the control register 103. The gradation voltage generation circuit 107 generates a gradation voltage used in the source line driver circuit 108. The source line driver circuit 108 uses the display data transmitted from the graphic RAM 105, selects a specific voltage from the gradation voltages created by the gradation voltage generation circuit 107, and outputs it as a liquid crystal source signal 110 to the outside. doing. The liquid crystal drive level generation circuit 109 generates a gate signal and a common signal 111 used for driving the liquid crystal and outputs them to the outside.

  The liquid crystal driver 101 configured as described above operates as follows.

  Display data is fetched from the outside via the system interface 102, and a display data saturation expansion process described later is performed by a saturation expansion circuit 104 and stored in the graphic RAM 105. The timing generation circuit 106 generates the graphic RAM read timing, and the display data is transferred to the source line driver circuit 108 at that timing. In this case, a voltage is selected from the gradation voltage generated by the gradation voltage generation circuit 107 using the above-described display data, and is transmitted to the liquid crystal panel 114 as the liquid crystal source signal 110. Further, using the timing generated by the timing generation circuit 106, the liquid crystal drive level generation circuit 109 generates a liquid crystal gate signal and a common signal 111, and transmits them to the liquid crystal panel 114.

  FIG. 2 shows a configuration example of the saturation expansion circuit 104.

  In the figure, 201 is an extraction circuit, 202 is display data, 203 is saturation data S, 204 is hue data H, 205 is lightness data V, 206 is a saturation expansion multiplier, 207 is a synthesis circuit, and 208 is post-expansion saturation. Data S ′ and 209 are saturation expansion coefficient k, 210 is a saturation expansion coefficient arithmetic circuit, 211 is an initial color gamut vertex coordinate register, 212 is a user target color gamut vertex coordinate register, and 213 is display data after expansion. The initial color gamut vertex coordinate register 211 is set with an initial color gamut vertex coordinate, and the user target color gamut vertex coordinate register 212 is set with a user target color gamut vertex coordinate (see FIG. 3). The initial color gamut vertex coordinates and the user target color gamut vertex coordinates are stored in a non-illustrated nonvolatile memory, and the setting of coordinate information in the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212 is as follows. This is performed via the system interface 102 every time the liquid crystal display device 100 is powered on.

  The extraction circuit 201 converts the R, G, and B values of the display data 202 transmitted from the system interface 102 into HSV and YCbCr, and extracts each parameter. When HSV is used, the saturation data (S) 203 is calculated from the equation shown in Equation 1, and the hue data (H) 204 expressed by 0 ° or more and less than 360 ° is the equation shown in Equation 3. The brightness data (V) 205 is calculated from the equation shown in Equation 4. The saturation data (S) 203 is output to the saturation expansion multiplier 206, and the hue data (H) 204 and lightness data (V) 205 are output to the synthesis circuit 207.

  However, max (R, G, B) is a function that takes the maximum value in (), and min (R, G, B) is a function that takes the minimum value in ().

  In the saturation expansion calculator 206, the value obtained by normalizing the saturation data (S) 203 with the lightness V is ns, and as shown in the equation 4, the saturation expansion coefficient (k) 209 is multiplied, and after the expansion The saturation data (S ′) 208 is output to the synthesis circuit 207.

  The saturation expansion coefficient (k) 209 is output from the saturation expansion coefficient calculation circuit 210. The saturation expansion coefficient calculation circuit 210 uses the method described later from the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212 to determine the saturation expansion coefficient (from the area ratio between the initial color gamut and the user target color gamut). k) 209 is calculated. The values of the initial color gamut vertex coordinate register 211 and the user target color gamut coordinate register 212 are represented by xy coordinates on the chromaticity diagram. The setting method will be described later.

  In the synthesis circuit 207, HSV data including the hue data (H) 204 output from the extraction circuit 201, the lightness data (V) 205, and the post-expansion saturation component (S ′) 208 output from the saturation expansion multiplier 206. Is converted into R, G, and B values in the following process, and is output as display data 213 after expansion.

  First, as shown in Equations 5 and 6, the hue H is divided by 60 and separated into an integer part Hi and a decimal part f of 0 to 5. However, the parentheses in Equation 5 mean the maximum integer value that does not exceed the value.

  Next, as shown in Equation 7, the converted values to R, G, and B are calculated from the post-expansion saturation data S ′ and the lightness V.

最後に、数８に示されるように、Ｈｉの値からＲ，Ｇ，Ｂの各値を決定する。

Finally, as shown in Equation 8, R, G, and B values are determined from the Hi value.

  Using these blocks, the saturation expansion circuit 104 operates as follows.

  The extraction circuit 201 extracts saturation data (S) 203, hue data (H) 204, and lightness data (V) 205 from the display data 202. Hue data (H) 204 and lightness data (V) 205 are output to the synthesis circuit 207.

  The saturation data (S) 203 is multiplied by the saturation expansion coefficient (k) 209 by the saturation expansion multiplier 206 and is output to the synthesis circuit 207 as post-expansion saturation (S ′) 208. The saturation expansion coefficient (k) 209 is calculated by the saturation expansion coefficient calculation circuit 210 from the values in the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212. The synthesizing circuit 207 converts the input HSV value into R, G, and B values, and then outputs the data as decompressed display data 213 to the graphic RAM 105 shown in FIG.

  FIG. 3 shows setting values of the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212.

  Reference numeral 301 denotes an initial color gamut, and 302 denotes a user target color gamut. An initial color gamut 301 is a color gamut when display data is output without being processed, and a user target color gamut 302 is a color gamut targeted by the user. As shown in FIG. 3, these color gamuts are represented by triangles with the values of R, G, and B as vertices, and the area can be calculated from the coordinates of the vertices. The coordinates in the R, G, and B values of the initial color gamut 301 are set in the initial color gamut vertex coordinate register 211, and the coordinates in the R, G, and B values in the user target color gamut 302 are the user target color gamut coordinate register 212. Set value.

  FIG. 4 shows a calculation flow of the saturation expansion coefficient in the saturation expansion coefficient calculation circuit 210.

  First, in step 401, the respective color gamut areas are calculated from the coordinate values stored in the initial color gamut vertex coordinate register 211 and the user target color gamut coordinate register 212. Next, in step 402, the saturation expansion coefficient (k) 209 is calculated by the equation shown in Equation 9 based on the area calculated in 401 described above.

  According to the above example, the following operational effects can be obtained.

  (1) The color gamut of the liquid crystal panel 114 cannot be expanded from the area 301 shown in FIG. 3, but within the area 301, 302 colors for low to medium chroma pixels. It is possible to obtain an effect of extending the color gamut to 302. Moreover, since the expansion coefficient of the saturation data is determined based on the initial color gamut vertex coordinates and the user target color gamut vertex coordinates, and the saturation of the display data is expanded based on the expansion coefficient, the color of the liquid crystal panel 114 It is possible to control the degree of extending the saturation according to the area.

  (2) Since the effect of (1) above enables saturation adjustment according to the color gamut of each panel, it is possible to correct the blue shift phenomenon that occurs in the low gradation data in the liquid crystal panel. It becomes.

<Embodiment 2>
FIG. 5 shows another configuration example of the saturation expansion circuit 104.

  The saturation expansion circuit 104 shown in FIG. 5 is greatly different from that shown in FIG. 2 in that an R, G, B saturation expansion coefficient calculation circuit 501 is provided in place of the saturation expansion coefficient calculation circuit 210. Further, a saturation expansion coefficient interpolation circuit 503 for interpolating R, G, B saturation expansion coefficients (kR, kG, kB) 502 based on the value of the hue data (H) 204 extracted from the display data 202 is provided. It is a point.

  The R, G, B saturation expansion coefficient calculation circuit 501 uses the method described later from the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212 to calculate the R, G, B vertices from the white coordinates. The R, G, B saturation expansion coefficient (kR, kG, kB) 502 is calculated from the ratio of the distance to the coordinates and the distance from the white coordinates to the R, G, B vertex coordinates. The R, G, B saturation expansion coefficient 502 is obtained by calculating the saturation expansion coefficient k at the time of R (H = 0 °), G (H = 120 °), and B (H = 240 °). .

  The saturation expansion interpolation circuit 503 linearly interpolates the R, G, B saturation expansion coefficient 502 calculated by the R, G, B saturation expansion number calculation circuit 501 with respect to the hue, and the saturation expansion coefficient k for each hue. Is output to the saturation expansion coefficient calculator 206. The calculation method will be described later.

  FIG. 6 shows a calculation flow of the R, G, B saturation expansion coefficient 502 in the R, G, B saturation expansion coefficient calculation circuit 501.

  First, in step 601, from the initial color gamut vertex coordinate value stored in the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate value stored in the user target color gamut vertex coordinate register 212, R , G, and B are calculated by the equation shown in Equation 10. However, (x, y) represents the xy coordinate value of the color coordinate for which saturation is to be obtained, and (x0, y0) represents the xy coordinate value of white in the color gamut.

  Next, in step 602, the R, G, B saturation expansion coefficient ((R, G, B) is calculated from the ratio between the R, G, B saturation values in the initial color gamut and the R, G, B saturation values in the user target color gamut. kR, kG, kB) 502 is calculated.

  FIG. 7 shows a configuration example of the saturation expansion coefficient interpolation circuit 503.

  701 is a hue data divider, 702 is a section determination value (hi), 703 is a linear interpolation coefficient (hf), 704 is an R, G, B saturation expansion coefficient table, 705 is a hue start point a, 706 is a hue end point b, Reference numeral 707 denotes a linear interpolation calculator.

  Hue data (H) 204 is input from the extraction circuit 201 to the hue data divider 701. The hue data (H) 204 is divided by 120, the integer part of the solution is output as an interval judgment value (hi) 702 to the R, G, B saturation expansion table 704, and the decimal part is linear interpolation coefficient (hf). The result is output to the linear interpolation calculator 707 as 703.

  The R, G, B saturation expansion coefficient table 704 includes an R, G, B saturation expansion coefficient arithmetic circuit 501 from the R, G, B saturation expansion coefficient 502, and a hue data divider 701 from the section determination value (hi ) 702 is input. Thereafter, as shown in Equation 11, a hue start point (a) 705 and a hue end point (b) 706 are determined and output to the linear interpolation calculator 707.

  The linear interpolation calculator 707 receives the linear interpolation coefficient (hf) 703 from the hue data divider 701 and the hue start point (a) 705 and hue end point (b) 706 from the R, G, B saturation expansion coefficient table 704. Is done. These are linearly interpolated as shown in Equation 12 to calculate a saturation expansion coefficient (k) 209 in arbitrary hue data H and output it to the saturation expansion multiplier 206.

  FIG. 8 shows a graph of the calculation result of the saturation expansion coefficient (k) 209 in each hue after linear interpolation is performed by the saturation expansion coefficient interpolation circuit 503.

  Even if the initial color gamut has a distorted shape, the shape can be apparently corrected by the stretching process. In addition, since the expansion coefficient of the saturation data is determined based on the initial color gamut vertex coordinates and the user target color gamut vertex coordinates, and the saturation of the display data is expanded based on the expansion coefficient, R, G, B The degree of extension of the saturation can be controlled according to the color characteristics. Further, in this example, since the change of the expansion coefficient k becomes smooth by performing linear interpolation, it is possible to perform satisfactory saturation expansion.

  In FIG. 9, the saturation expansion calculator 206 multiplies the saturation expansion coefficient (k) 209 in each hue and the saturation data (S) 203 as shown in FIG. A graph of the degree data (S ′) 208 for each hue is shown. In this way, the display data having a certain saturation S is expanded by various hues H, the display data after expansion is measured, and the saturation data (S ′) after expansion is obtained, thereby using this method. It becomes possible to clarify what is being done.

<Embodiment 3>
FIG. 10 shows another configuration example of the saturation expansion circuit 104.

  The saturation expansion circuit 104 shown in FIG. 10 is greatly different from that shown in FIG. 5 in that the initial color gamut vertex coordinate register 211, the user target color gamut vertex coordinate register 212, and the R, G, and B saturations. Instead of the expansion number calculation circuit 501, an R, G, B saturation expansion register 1001 is provided.

  As a value of the R, G, B saturation expansion register 1001, for example, an R, G, B saturation expansion coefficient calculated according to the flowchart shown in FIG. 6 is set. The calculated R, G, B saturation expansion coefficients are stored in a nonvolatile memory (not shown), and R, G, B saturation expansion is performed via the system interface 102 every time the liquid crystal display device 100 is turned on. It can be configured to be transferred to the coefficient register 1001. Thus, by using the R, G, B saturation expansion register 1001 instead of the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212, the same effect as in the second embodiment can be obtained. Can be obtained. In the case of this example, the initial color gamut vertex coordinate register 211, the user target color gamut vertex coordinate register 212, and the R, G, B saturation expansion number calculation circuit 501 are not required. Can be simplified.

  Although the invention made by the present inventor has been specifically described above, the present invention is not limited thereto, and it goes without saying that various changes can be made without departing from the scope of the invention.

  For example, in the above configuration example, the initial color gamut vertex coordinate register 211, the user target color gamut vertex coordinate register 212, or the R, G, B saturation expansion coefficient register 1001 is provided in the saturation expansion circuit 104. Instead, a part of the control register 103 may be used.

  In the above description, the case where the invention made by the present inventor is applied to the liquid crystal driver which is the field of use behind the invention has been described. However, the present invention is not limited to this and is applied to various display driving circuits. can do.

DESCRIPTION OF SYMBOLS 100 Liquid crystal display device 101 Liquid crystal driver 102 System interface 103 Control register 104 Saturation expansion part 105 Graphic RAM
106 timing generation circuit 107 grayscale voltage generation circuit 108 source line drive circuit 109 liquid crystal drive level generation circuit 110 liquid crystal source signal 111 liquid crystal gate signal, common signal 112 backlight power supply line 113 control processor 114 liquid crystal panel 115 backlight module 201 extraction circuit 202 Display data 203 Saturation data (S)
204 Hue data (H)
205 Lightness data (V)
206 Saturation Expansion Multiplier 207 Synthesis Circuit 208 Decompression Saturation Data (S ′)
209 Saturation expansion coefficient (k)
210 Saturation expansion arithmetic circuit 211 Initial color gamut vertex coordinate register 212 User target color gamut vertex coordinate register 213 Display data after expansion 301 Initial color gamut 302 User target color gamut 501 R, G, B saturation expansion coefficient arithmetic circuit 502 R, G, B saturation expansion coefficient (kR, kG, kB)
503 Saturation extension interpolation circuit 701 Hue data divider 702 Section judgment place (hi)
703 Linear interpolation coefficient (hf)
704 R, G, B saturation expansion coefficient table 705 Hue start point (a)
706 Hue end point (b)
707 Linear interpolation calculator 1001 R, G, B saturation expansion coefficient register

The saturation data (S) 203 is multiplied by the saturation expansion coefficient (k) 209 by the saturation expansion multiplier 206 and output to the synthesis circuit 207 as post-expansion saturation data (S ′) 208. . The saturation expansion coefficient (k) 209 is calculated by the saturation expansion coefficient calculation circuit 210 from the values in the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212. The synthesizing circuit 207 converts the input HSV value into R, G, and B values, and then outputs the data as decompressed display data 213 to the graphic RAM 105 shown in FIG.

301 represents an initial color gamut, and 302 represents a user target color gamut. An initial color gamut 301 is a color gamut when display data is output without being processed, and a user target color gamut 302 is a color gamut targeted by the user. As shown in FIG. 3, these color gamuts are represented by triangles with the values of R, G, and B as vertices, and the area can be calculated from the coordinates of the vertices. The coordinates in the R, G, B values of the initial color gamut 301 are set in the initial color gamut vertex coordinate register 211, and the coordinates in the R, G, B values in the user target color gamut 302 are the user target color gamut vertex coordinate registers. The set value is 212.

First, in step 401, the respective color gamut areas are calculated from the coordinate values stored in the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212. Next, in step 402, the saturation expansion coefficient (k) 209 is calculated by the equation shown in Equation 9 based on the area calculated in 401 described above.

R, G, B color saturation expansion coefficient calculating circuit 501, the initial gamut vertex coordinate register 211, using a method described later from the user the target gamut vertex coordinate register 212, R from white coordinate, G, each initial B and the distance to the color gamut vertex coordinates, R from white coordinate, G, R from the ratio of the distance to each user goal gamut vertex coordinates of B, G, B color saturation expansion factor (kR, kG, kB) to 502 calculate. The R, G, B saturation expansion coefficient 502 is obtained by calculating the saturation expansion coefficient k at the time of R (H = 0 °), G (H = 120 °), and B (H = 240 °). .

Saturation decompression interpolation circuit 503, R, G, R, which is calculated by B saturation expansion coefficient calculating circuit 501, G, and B color saturation expansion factor 502 linearly interpolated for hue, saturation expansion coefficient in the hue k is calculated and output to the saturation expansion coefficient calculator 206. The calculation method will be described later.

As a value of the R, G, B saturation expansion register 1001, for example, an R, G, B saturation expansion coefficient calculated according to the flowchart shown in FIG. 6 is set. The calculated R, G, B saturation expansion coefficients are stored in a nonvolatile memory (not shown), and R, G, B saturation expansion is performed via the system interface 102 every time the liquid crystal display device 100 is turned on. It can be configured to be transferred to the coefficient register 1001. Thus, by using the R, G, B saturation expansion register 1001 instead of the initial color gamut vertex coordinate register 211 and the user target color gamut vertex coordinate register 212, the same effect as in the second embodiment can be obtained. Can be obtained. In the case of this example, since the initial gamut vertex coordinate register 211, the user target gamut vertex coordinate register 212, and R, G, B color saturation expansion coefficient calculating circuit 501 is not necessary, that amount, hardware The configuration can be simplified.

DESCRIPTION OF SYMBOLS 100 Liquid crystal display device 101 Liquid crystal driver 102 System interface 103 Control register 104 Saturation expansion part 105 Graphic RAM
106 timing generation circuit 107 grayscale voltage generation circuit 108 source line drive circuit 109 liquid crystal drive level generation circuit 110 liquid crystal source signal 111 liquid crystal gate signal, common signal 112 backlight power supply line 113 control processor 114 liquid crystal panel 115 backlight module 201 extraction circuit 202 Display data 203 Saturation data (S)
204 Hue data (H)
205 Lightness data (V)
206 Saturation Expansion Multiplier 207 Synthesis Circuit 208 Decompression Saturation Data (S ′)
209 Saturation expansion coefficient (k)
210 Saturation expansion arithmetic circuit 211 Initial color gamut vertex coordinate register 212 User target color gamut vertex coordinate register 213 Display data after expansion 301 Initial color gamut 302 User target color gamut 501 R, G, B saturation expansion coefficient arithmetic circuit 502 R, G, B saturation expansion coefficient (kR, kG, kB)
503 Saturation expansion interpolation circuit 701 Hue data divider 702 Section judgment value (hi)
703 Linear interpolation coefficient (hf)
704 R, G, B saturation expansion coefficient table 705 Hue start point (a)
706 Hue end point (b)
707 Linear interpolation calculator 1001 R, G, B saturation expansion coefficient register

Claims (2)

A display drive circuit capable of driving a liquid crystal panel according to input display data,
Interface,
A saturation expansion circuit that receives the display data supplied to the interface and performs a saturation expansion process of the display data, the saturation expansion circuit,
An extraction circuit for extracting saturation data, hue data and brightness data of the display data;
An initial color gamut vertex coordinate storage unit capable of storing an initial color gamut vertex coordinate supplied from the interface;
A user target color gamut vertex coordinate storage unit capable of storing user target color gamut vertex coordinates supplied from the interface;
A saturation expansion coefficient determination unit that determines a saturation expansion coefficient of saturation data based on the initial color gamut vertex coordinates and the user target color gamut vertex coordinates;
An expansion unit that expands the saturation of the display data based on the saturation expansion coefficient;
A synthesis circuit that synthesizes the hue data output from the extraction circuit, the lightness data, and the data after saturation expansion output from the expansion unit to generate display data after saturation expansion;
The display data includes R, G, B,
The saturation expansion coefficient determining unit outputs the saturation expansion coefficients of the R, G, and B,
The R, G, B saturation expansion coefficients and the hue data are received, the R, G, B saturation expansion coefficients are interpolated, and the post-interpolation saturation expansion coefficients are output to the expansion unit. A display drive circuit comprising a saturation expansion coefficient interpolation unit.   The saturation expansion coefficient determination unit obtains a distance from the white coordinate at each of the initial color gamut vertex coordinates and the user target color gamut vertex coordinates for each of R, G, and B values, and determines from the initial color gamut vertex coordinates and the white coordinates. The display drive circuit according to claim 1, wherein a saturation expansion coefficient for each of R, G, and B is calculated from a ratio of a distance between the color coordinates and a distance from a white coordinate at the user target color gamut vertex position.

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