Display driver IC including dithering circuit capable of adaptively changing threshold grayscale value depending on display brightness value, device including the same, and method thereof

Patent metadata

Field	Value
Publication number	US-11810495-B2
Application number	US-202217960435-A
Country	US
Kind code	B2
Filing date	Oct 5, 2022
Priority date	Feb 17, 2022
Publication date	Nov 7, 2023
Grant date	Nov 7, 2023

Abstract

Disclosed is a display driver integrated circuit (IC) which includes a data line driver that drives a first data line connected with a first pixel of a display in response to output image data, and a dithering circuit that receives a brightness value of the display, calculates a first reference grayscale value corresponding to the brightness value using a first group of threshold grayscale values, receives input image data with a first grayscale value, which corresponds to the first pixel, compares the first grayscale value and the first reference grayscale value, and generates the output image data having not the first grayscale value but an output grayscale value when the first grayscale value is smaller than the first reference grayscale value.

First claim

What is claimed is:

1. A display driver integrated circuit (IC), comprising:
a data line driver configured to drive a first data line connected with a first pixel of a display in response to output image data; and
a dithering circuit configured to receive a brightness value of the display, to calculate a first reference grayscale value corresponding to the brightness value using a first group of threshold grayscale values, to receive input image data with a first grayscale value, which corresponds to the first pixel, to compare the first grayscale value and the first reference grayscale value, and to generate the output image data having not the first grayscale value but an output grayscale value when the first grayscale value is smaller than the first reference grayscale value.

2. The display driver IC as claimed in claim 1 , wherein the dithering circuit selects one of the first group of threshold grayscale values as the output grayscale value.

3. The display driver IC as claimed in claim 1 , wherein the dithering circuit is configured to:
calculate a second reference grayscale value corresponding to the brightness value using a first group of minimum grayscale values;
compare the first grayscale value and the second reference grayscale value; and
select one of the first group of threshold grayscale values and the first group of minimum grayscale values as the output grayscale value when the first grayscale value is greater than the second reference grayscale value and is smaller than the first reference grayscale value.

4. The display driver IC as claimed in claim 3 , wherein the dithering circuit is configured to:
read a K*K dither pattern which corresponds to the first grayscale value and includes K 2 data elements including at least one first data element and at least one second data element, from a memory device, K being a natural number of 2 or more;
select one of the first group of threshold grayscale values as the output grayscale value when a data element matched with the first grayscale value from among the K 2 data elements is the first data element; and
select one of the first group of minimum grayscale values as the output grayscale value when the data element matched with the first grayscale value from among the K 2 data elements is the second data element.

5. The display driver IC as claimed in claim 3 , wherein the dithering circuit is configured to:
interpolate the threshold grayscale values of the first group of threshold grayscale values to calculate the first reference grayscale value; and
interpolate the minimum grayscale values of the first group of minimum grayscale values to calculate the second reference grayscale value.

6. The display driver IC as claimed in claim 1 , wherein the dithering circuit is configured to:
read a K*K dither pattern which corresponds to the first grayscale value and includes K 2 data elements including at least one first data element and at least one second data element, from a memory device, K being a natural number of 2 or more;
select one of the first group of threshold grayscale values as the output grayscale value when a data element matched with the first grayscale value from among the K 2 data elements is the first data element; and
select a minimum grayscale value as the output grayscale value when the data element matched with the first grayscale value from among the K 2 data elements is the second data element.

7. The display driver IC as claimed in claim 1 , wherein the dithering circuit is configured to:
read a K*K dither pattern which corresponds to the first grayscale value and includes K 2 data elements including at least one first data element and at least one second data element, from a memory device, K being a natural number of 2 or more;
calculate a count value by counting a number of data elements each corresponding to the first data element from among the K 2 data elements; and
select one corresponding to the count value from among a second group of threshold grayscale values as the output grayscale value.

8. The display driver IC as claimed in claim 7 , wherein the dithering circuit is configured to:
select the one corresponding to the count value as the output grayscale value when a data element matched with the first grayscale value from among the K 2 data elements is the first data element; and
select a minimum grayscale value as the output grayscale value when the data element matched with the first grayscale value from among the K 2 data elements is the second data element.

9. The display driver IC as claimed in claim 1 , wherein the dithering circuit is configured to:
calculate a second reference grayscale value corresponding to the brightness value using a first group of minimum grayscale values; and
compare the first grayscale value and the second reference grayscale value, and
when the first grayscale value is greater than the second reference grayscale value and is smaller than a first threshold grayscale value:
read a K*K dither pattern which corresponds to the first grayscale value and includes K 2 data elements including at least one first data element and at least one second data element, from a memory device, K being a natural number of 2 or more;
calculate a count value by counting a number of data elements each corresponding to the first data element from among the K 2 data elements;
select one corresponding to the count value from among a second group of threshold grayscale values associated with the first data element as the output grayscale value when a data element matched with the first grayscale value from among the K 2 data elements is the first data element; and
select one corresponding to the count value from among a second group of minimum grayscale values associated with the second data element as the output grayscale value when the data element matched with the first grayscale value from among the K 2 data elements is the second data element.

10. The display driver IC as claimed in claim 1 , wherein the dithering circuit includes:
a reference grayscale value calculation circuit configured to calculate the first reference grayscale value;
a threshold grayscale value calculation circuit; and
a comparing circuit configured to compare the first grayscale value and the first reference grayscale value, to bypass the input image data as the output image data to the data line driver when the first grayscale value is equal to or greater than the first reference grayscale value, and to output the input image data to the threshold grayscale value calculation circuit when the first grayscale value is smaller than the first reference grayscale value.

11. The display driver IC as claimed in claim 10 , wherein the threshold grayscale value calculation circuit is configured to:
read a K*K dither pattern which corresponds to the first grayscale value and includes K 2 data elements including at least one first data element and at least one second data element, from a memory device, K being a natural number of 2 or more;
select one of the first group of threshold grayscale values as the output grayscale value when a data element matched with the first grayscale value from among the K 2 data elements is the first data element; and
select a minimum grayscale value as the output grayscale value when the data element matched with the first grayscale value from among the K 2 data elements is the second data element.

12. The display driver IC as claimed in claim 1 , wherein:
the dithering circuit includes:
a reference grayscale value calculation circuit configured to calculate the first reference grayscale value and to calculate a second re

Assignees

• Samsung Electronics Co Ltd

Inventors

• Jang Byoungyoon
• Yu Yong Hoon
• Na Se Whan
• Na Jong-Hee
• Park Hyeonsu

Classifications

• G09G3/2044 Primary

  using dithering · CPC title

• G09G2320/0233

  Improving the luminance or brightness uniformity across the screen · CPC title

• G09G2320/0626

  for control of overall brightness · CPC title

• G09G2360/145

  the light originating from the display screen · CPC title

• G09G2320/0285

  using tables for spatial correction of display data · CPC title