Display driver, electro-optical device, electronic apparatus, and mobile body

Patent metadata

Field	Value
Publication number	US-10991295-B2
Application number	US-202016919165-A
Country	US
Kind code	B2
Filing date	Jul 2, 2020
Priority date	Jul 5, 2019
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

A display driver (100) drives a liquid crystal panel (200) that is driven by a static drive method. The display driver (100) includes an interface circuit (110), a selection circuit (120), and a drive circuit (130). The interface circuit (110) receives instruction information and display data from the outside. The selection circuit (120) selects n pieces of selected duty ratio data, which are n pieces of duty ratio data of k pieces of duty ratio data, based on the instruction information. The drive circuit (130) selects output duty ratio data corresponding to a tone value indicated by the display data from the n pieces of selected duty ratio data, and performs PWM driving of the liquid crystal panel (200) by outputting a drive signal having a duty ratio indicated by the selected output duty ratio data.

First claim

What is claimed is:

1. A display driver that drives a liquid crystal panel that is driven by a static drive method, the display driver comprising:
an interface circuit configured to receive instruction information and display data from outside;
a selection circuit configured to select n pieces of selected duty ratio data, which are n pieces of duty ratio data of k pieces of duty ratio data (n is an integer smaller than k), based on the instruction information; and
a drive circuit configured to select output duty ratio data corresponding to a tone value indicated by the display data from the n pieces of selected duty ratio data, and performs PWM driving of the liquid crystal panel by outputting a drive signal having a duty ratio indicated by the selected output duty ratio data.

2. The display driver according to claim 1 , wherein the n pieces of selected duty ratio data are pieces of data that are set such that the interval of duty ratios in a region in which the change in transmittance of the liquid crystal panel relative to the change in effective voltage of the drive signal is large is smaller than the interval of duty ratios in a region in which the change in transmittance of the liquid crystal panel relative to the change in effective voltage of the drive signal is small.

3. The display driver according to claim 1 , wherein the selection circuit is configured to select the n pieces of selected duty ratio data by selecting a duty ratio data set corresponding to the instruction information from a first duty ratio data set that is constituted by a first group of n pieces of duty ratio data and a second duty ratio data set that is constituted by a second group of n pieces of duty ratio data that is different from the first group.

4. The display driver according to claim 3 , wherein the selection circuit is configured to select the first duty ratio data set when the instruction information is information for instructing driving of a first liquid crystal panel, and select the second duty ratio data set when the instruction information is information for instructing driving of a second liquid crystal panel.

5. The display driver according to claim 1 , wherein the drive circuit is configured to perform the PWM driving based on a clock signal whose frequency is higher than the frequency obtained by multiplying the frame frequency of the PWM driving by n.

6. The display driver according to claim 1 , wherein the k pieces of duty ratio data are pieces of data respectively indicating duty ratios of the PWM driving at equal intervals.

7. The display driver according to claim 1 , wherein the drive circuit is configured to drive a segment electrode of the liquid crystal panel.

8. The display driver according to claim 1 , further comprising a temperature sensor,
wherein the drive circuit is configured to perform the PWM driving at a frame frequency that changes based on a temperature detection result of the temperature sensor.

9. An electro-optical device comprising:
the display driver according to claim 1 ; and
the liquid crystal panel.

10. An electronic apparatus comprising the display driver according to claim 1 .

11. A mobile body comprising the display driver according to claim 1 .

Assignees

• Seiko Epson Corp

Inventors

• Takizawa Ryota
• Muraki Norichika

Classifications

• G09G2320/0271

  Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping · CPC title

• G09G2340/0435

  Change or adaptation of the frame rate of the video stream · CPC title

• G09G3/3614 Primary

  Control of polarity reversal in general · CPC title

• G09G3/2018 Primary

  by time modulation using two or more time intervals · CPC title

• G09G2320/0276

  for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction · CPC title