Voltage drop compensator for display panel and display device including the same

Patent metadata

Field	Value
Publication number	US-2016240140-A1
Application number	US-201514857609-A
Country	US
Kind code	A1
Filing date	Sep 17, 2015
Priority date	Feb 13, 2015
Publication date	Aug 18, 2016
Grant date	—

Abstract

A voltage drop compensator for a display device and the display device including the same are disclosed. In one aspect, the voltage drop compensator includes a region divider, an expected current calculator, a conversion matrix generator, a representative voltage calculator, and a compensator. The region divider is configured to divide the display panel into a plurality of regions, and the display panel includes a plurality of power lines and a plurality of pixels configured to receive a power voltage via the power lines. The expected current calculator is configured to calculate an expected current to flow in each of the regions based on input data provided to each of the regions. The conversion matrix generator configured to generate a conversion matrix based on a line resistance of each of the power lines and convert the expected current to a representative voltage provided to the regions based on the conversion matrix.

First claim

What is claimed is:

1 . A voltage drop compensator for a display panel, comprising:
a region divider configured to divide the display panel into a plurality of regions, wherein the display panel includes a plurality of power lines and a plurality of pixels configured to receive a power voltage via the power lines; an expected current calculator configured to calculate an expected current to flow in each of the regions based on input data provided to each of the regions; a conversion matrix generator configured to generate a conversion matrix based on a line resistance of each of the power lines and convert the expected current to a representative voltage provided to the regions based on the conversion matrix; a representative voltage calculator configured to multiply the conversion matrix and the expected current so as to calculate the representative voltage; and a compensator configured to calculate an amount of a voltage drop in each of the regions based on the representative voltage and output a compensated data so as to compensate for the amount of the voltage drop in each of the regions.

2 . The voltage drop compensator of claim 1 , wherein the conversion matrix generator is further configured to generate the conversion matrix based on a power current flowing through each of the power lines.

3 . The voltage drop compensator of claim 2 , wherein the power lines are formed over the display panel in a first direction and a second direction crossing the first direction.

4 . The voltage drop compensator of claim 3 , wherein the conversion matrix generator is further configured to generate a resistance matrix based on the equation, “Z(m,n)={V(m,n−1)−2V(m,n)+V(m,n+1)}/R1+{V(m−1, n)−2V(m, n)+V(m+1 ,n)}/R2”, where the m, n are natural numbers equal to or greater than 1, Z is the expected current, V is the representative voltage, R1 is the line resistance of the power lines formed in the first direction, and R2 is the line resistance of the power lines formed in the second direction, and wherein the conversion matrix generator is further configured to generate an inverse of the resistance matrix as the conversion matrix.

5 . The voltage drop compensator of claim 2 , wherein the power lines are formed in a first direction.

6 . The voltage drop compensator of claim 5 , wherein the conversion matrix generator is further configured to generate a resistance matrix based on the equation, “Z(m,n)={V(m,n−1)−2V(m,n)+V(m,n+1)}/R1”, where the m, n are natural numbers equal to or greater than 1, Z is the expected current, V is the representative voltage, and R1 is the line resistance of the power lines formed in the first direction, and wherein the conversion matrix generator is further configured to generate an inverse of the resistance matrix as the conversion matrix.

7 . The voltage drop compensator of claim 2 , wherein the power lines are formed in a second direction crossing a first direction.

8 . The voltage drop compensator of claim 7 , wherein the conversion matrix generator is further configured to generate a resistance matrix based on the equation, “Z(m,n)={V(m−1, n)−2V(m, n)+V(m+1,n)}/R2”, where the m, n are natural numbers equal to or greater than 1, Z is the expected current, V is the representative voltage, and R2 is the line resistance of the power lines formed in the second direction, and wherein the conversion matrix generator is further configured to generate an inverse of the resistance matrix as the conversion matrix.

9 . The voltage drop compensator of claim 1 , wherein the conversion matrix generator includes a look up table (LUT) configured to store the conversion matrix.

10 . The voltage drop compensator of claim 1 , wherein the expected current calculator is further configured to calculate the expected current corresponding to grayscale values of the input data based on a predetermined ratio.

11 . The voltage drop compensator of claim 1 , wherein the expected current calculator includes a look up table (LUT) configured to store the expected current corresponding to grayscale values of the input data.

12 . The voltage drop compensator of claim 1 , further comprising an interpolator configured to interpolate the representative voltages of the regions.

13 . A display device, comprising:
a display panel including a plurality of power lines and a plurality of pixels configured to receive a power voltage via the power lines; a voltage drop compensator configured to divide the display panel into a plurality of regions, calculate a conversion matrix based on a line resistance of each of the power lines, multiply the conversion matrix and an expected current to flow in the regions so as to calculate a representative voltage of the regions, and compensate for an amount of a voltage drop of the regions based on the representative voltage; a data driver configured to provide a data signal to the pixels; a scan driver configured to provide a scan signal to the pixels; and a timing controller configured to control the data driver, the scan driver, and the voltage drop compensator.

14 . The display device of claim 13 , wherein the voltage drop compensator includes:
a region divider configured to divide the display panel into the regions; an expected current calculator configured to calculate the expected current to flow in each of the regions based on input data provided to each of the regions; a conversion matrix generator configured to generate the conversion matrix and convert the expected current to the representative voltage provided to the regions based on the line resistance of each of the power lines; a representative voltage calculator configured to multiply the conversion matrix and the expected current so as to calculate the representative voltage; and a compensator configured to calculate the amount of the voltage drop in each of the regions based on the representative voltage and output compensated data so as to compensate for the amount of the voltage drop in each of the regions.

15 . The display device of claim 14 , wherein the conversion matrix generator is further configured to generate the conversion matrix based on the power current flowing through each of the power lines.

16 . The display device of claim 15 , wherein the conversion matrix generator is further configured to generate a resistance matrix based on the equation, “Z(m,n)={V(m,n−1)−2V(m,n)+V(m,n+1)}/R1+{V(m−1, n)−2V(m, n)+V(m+1,n)}/R2”, where the m, n are natural numbers equal to or greater than 1, Z is the expected current, V is the representative voltage, R1 is the line resistance of the power lines formed in a first direction, and R2 is the line resistance of the power lines formed in a second direction, wherein the conversion matrix generator is further configured to generate an inverse of the resistance matrix as the conversion matrix, and wherein the power lines are formed in the first direction and the second direction crossing the first direction on the display panel.

17 . The display device of claim 15 , wherein the conversion matrix generator is further configured to generate a resistance matrix based on the equation, “Z(m,n)={V(m,n−1)−2V(m,n)+V(m,n+1)}/R1”, where the m, n are natural numbers equal to or greater than 1, Z is the expected current, V is the representative voltage, and R1 is the line resistance of the power lines formed in a first direction, wherein the conversion matrix generator is further configured to generate an inverse of the resistance matrix as the conversion matrix, and wherein the power lines are formed in the first direction on the d

Assignees

• Samsung Display Co Ltd

Inventors

• Park Gilbae
• Park Heesook
• Baik Joonsuk
• Eom Jihye

Classifications

• G09G3/3258 Primary

  with pixel circuitry controlling the voltage across the light-emitting element · CPC title

• G09G2300/043

  Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver · CPC title

• G09G3/3208 Primary

  organic, e.g. using organic light-emitting diodes [OLED] · CPC title

• G09G3/30

  using electroluminescent panels · CPC title

• G09G3/3666

  with the matrix divided into sections · CPC title