Method for designing a structure for driving display devices

1 . A method of creating a structure for driving display devices comprising the steps of:

considering transmittance characteristics in relation to voltages applied to a plurality of liquid crystal displays;

defining a transmittance curve based on the voltages applied to said liquid crystal displays, for each liquid crystal display of said plurality;

applying a gamma correction, with different values of a gamma exponent, to each transmittance curve to obtain gamma corrected curves for each liquid crystal display;

applying a kickback correction to each gamma corrected curve to obtain kickback corrected curves;

positioning a plurality of branch points along said kickback corrected curves;

determining a resistance value for each branch point of each kickback corrected curve for each liquid crystal display;

choosing a value of minimum resistance for each branch point;

choosing a value of maximum resistance for each branch point;

calculating a difference between said value of minimum resistance for each branch point and said value of maximum resistance for each branch point;

defining for each branch point a value of fixed resistance equal to said value of minimum resistance;

defining for each branch point an interval of values for a variable resistance equal to said difference; and

creating a voltage divider network having fixed resistances according to said minimum resistance for each branch point and variable resistances that are based on the defined interval values.

2 . A method in accordance with claim 1 wherein positioning the plurality of branch points along said kickback corrected curves for each display comprises positioning said plurality of branch points equidistant to one another.

3 . A method in accordance with claim 1 wherein positioning the plurality of branch points along said kickback corrected curves for each display comprises positioning a higher number of branch points in zones of said kickback corrected curves in which that have greater changes of slope.

4 . A method in accordance with claim 1 wherein determining the resistance value for each branch point comprises determining a plurality of resistance values to be applied between each couple of branch points.

5 . A method in accordance with claim 1 , further comprising determining voltage values of a number of grey levels by means of the resistance values previously defined.

6 . A method in accordance with claim 5 wherein said number of branch points is equal to 16 and said number of grey levels is equal to 64.

7 . A method in accordance with claim 1 wherein the voltage divider network includes a plurality of fixed/variable resistance pairs connected between first and second voltage references and separated from one another by a respective branch node of a plurality of branch nodes, each fixed/variable resistance pair including one of the fixed resistances and one of the variable resistances.

8 . A method in accordance with claim 7 wherein the voltage divider network further includes:

a plurality of buffers connected respectively between the branch nodes and a corresponding plurality of output nodes;

a plurality of groups of further fixed resistances, each group of further fixed resistances being connected between consecutive ones of the output nodes; and

a plurality of further output nodes positioned between consecutive ones of the further fixed resistances.

9 . A method in accordance with claim 7 wherein each of the variable resistances includes a plurality of fixed resistors and a corresponding plurality of switches each in parallel with a respective one of the fixed resistors.

10 . A method of creating a structure for driving a display device, comprising:

determining a plurality of branch points along a plurality of curves that have been corrected based on gamma correction values and kickback correction values;

determining a value of minimum resistance for each branch point;

determining a value of maximum resistance for each branch point;

calculating a difference between said value of minimum resistance for each branch point and said value of maximum resistance for each branch point; and

creating a voltage divider network having fixed resistances according to said minimum resistance for each branch point and variable resistances that are based on the defined interval values.

11 . A method in accordance with claim 10 wherein determining the plurality of branch points comprises determining said plurality of branch points equidistant to one another.

12 . A method in accordance with claim 10 wherein determining the plurality of branch points comprises positioning a higher number of branch points in zones of said curves in which that have greater changes of slope.

13 . A method in accordance with claim 10 , further comprising determining a resistance value for each branch point by determining a plurality of resistance values to be applied between each couple of branch points.

14 . A method in accordance with claim 10 wherein the voltage divider network includes a plurality of fixed/variable resistance pairs connected between first and second voltage references and separated from one another by a respective branch node of a plurality of branch nodes, each fixed/variable resistance pair including one of the fixed resistances and one of the variable resistances.

15 . A method in accordance with claim 14 wherein the voltage divider network further includes:

a plurality of buffers connected respectively between the branch nodes and a corresponding plurality of output nodes;

a plurality of groups of further fixed resistances, each group of further fixed resistances being connected between consecutive ones of the output nodes; and

a plurality of further output nodes positioned between consecutive ones of the further fixed resistances.

16 . A method in accordance with claim 14 wherein each of the variable resistances includes a plurality of fixed resistors and a corresponding plurality of switches each in parallel with a respective one of the fixed resistors.

17 . A display device driver, comprising:

a first voltage divider leg connected between first and second reference voltages, the first voltage divider leg including a plurality of fixed/variable resistance pairs separated from one another by a respective branch node of a plurality of branch nodes, each fixed/variable resistance pair including a fixed resistance and a variable resistance, each branch node thereby having a minimum voltage value determining by the fixed resistance of one of the fixed/variable resistance pairs that corresponds to the branch node and having a range of voltage values that is variable from the minimum voltage value to a maximum voltage value as determined by the variable resistances of the corresponding fixed/variable resistance pair.

18 . The display device driver of claim 17 , further comprising:

a plurality of buffers connected respectively between the branch nodes and a corresponding plurality of output nodes;

a plurality of groups of further fixed resistances, each group of further fixed resistances being connected between consecutive ones of the output nodes; and

a plurality of further output nodes positioned between consecutive ones of the further fixed resistances.

19 . The display device driver of claim 17 wherein each of the variable resistances includes a plurality of fixed resistors and a corresponding plurality of switches each in parallel with a respective one of the fixed resistors.