Liquid crystal display device

Patent metadata

Field	Value
Publication number	US-10923014-B2
Application number	US-202016837744-A
Country	US
Kind code	B2
Filing date	Apr 1, 2020
Priority date	Nov 25, 2016
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A liquid crystal display device comprises: a first display panel displaying a color image; a second display panel displaying a monochrome image; and an image processor generating first image data corresponding to the color image and second image data corresponding to the monochrome image based on an input video signal. The image processor generates the first image data and the second image data such that a graph representing transmittance of the first display panel for input gradation corresponding to the input video signal and a graph representing transmittance of the second display panel for the input gradation corresponding to the input video signal intersect each other at predetermined input gradation.

First claim

What is claimed is:

1. A liquid crystal display device comprising:
a first display panel that displays a first image;
a second display panel that displays a second image; and
an image processor that generates first image data corresponding to the first image and second image data corresponding to the second image based on an input video signal,
wherein the liquid crystal display device is configured so that the transmittance of the first display panel is larger than the transmittance of the second display panel when a value of luminance information of the input video signal is less than a first value, and the transmittance of the second display panel is larger than the transmittance of the first display panel when the value of the luminance information of the input video signal is more than the first value,
wherein the image processor includes a first image data generator that decides first gradation corresponding to the first image data and a second image data generator that decides second gradation corresponding to the second image data, the second image data generator decides the second gradation lower than the first gradation based on the input gradation corresponding to the input video signal when a value of luminance information of the input video signal is less than the first value.

2. The liquid crystal display device according to claim 1 , wherein the first image data generator decides the first gradation based on the second gradation decided by the second image data generator.

3. The liquid crystal display device according to claim 2 , further comprising a correction table in which the second gradation is correlated with a correction value to be used for correcting the input gradation,
wherein the first image data generator refers to the correction table to obtain the correction value, which is correlated with the second gradation decided by the second image data generator, and corrects the input gradation to calculate the first gradation based on the obtained correction value.

4. The liquid crystal display device according to claim 3 , wherein the correction value is set such that a compound transmittance, in which the transmittance of the first display panel and the transmittance of the second display panel are compounded, comes close to transmittance corresponding to a predetermined gamma value.

5. The liquid crystal display device according to claim 1 , wherein
the second display panel is disposed closer to a side of a backlight than the first display panel.

6. The liquid crystal display device according to claim 1 , wherein
the first display panel displays a color image, and
the second display panel displays a monochrome image.

Assignees

• Panasonic Liquid Crystal Displ
• Pasona Knowledge Partner Inc

Inventors

• Koudo Toshikazu
• Ishii Masahiro
• Kikuchi Katsuhiro
• Mori Ikuko

Classifications

• G09G3/3607 Primary

  for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels (display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127) · CPC title

• G09G3/36

  using liquid crystals · CPC title

• G09G2320/0673

  for control of gamma adjustment, e.g. selecting another gamma curve · CPC title

• G09G3/3648

  using an active matrix (G09G3/367 - G09G3/3696 take precedence) · CPC title

• G09G2320/066

  for control of contrast · CPC title