Dual Liquid Crystal Panels for High Contrast Display

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Solution Overview

Problem

Conventional liquid crystal display devices struggle to adequately shield illumination light, leading to pixels with the darkest gradation appearing slightly white due to a contrast ratio of 1000:1, which is insufficient for proper image representation.

Innovation Solution

A display device comprising a first transmissive display panel and a second display panel, where the second panel is arranged to superimpose subpixels at a predetermined distance, allowing for a significant difference in light transmittance between bright and dark gradations, thereby enhancing the contrast ratio to 1000000:1 by using a controller to control the subpixels based on image data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single liquid crystal panel is used for display, then the device structure is simple, but the contrast ratio is insufficient (1000:1) causing darkest pixels to appear white

Engineering Contradiction:

Improvedisplay structureVSAvoidcontrast ratio

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The single display panel is segmented into two separate liquid crystal panels (first liquid crystal panel and second liquid crystal panel) with different transmittance characteristics. The first panel uses a high transmittance liquid crystal layer while the second panel uses a low transmittance liquid crystal layer, allowing each panel to contribute differently to the overall contrast performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention combines two liquid crystal panels with different material properties (high transmittance and low transmittance) to create a composite display system. This composite structure achieves a contrast ratio of 1000000:1 by multiplying the contrast ratios of individual panels, overcoming the limitation of single-panel displays.

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If a high transmittance liquid crystal layer is used, then bright gradations are well displayed, but dark gradations cannot be sufficiently shielded

Engineering Contradiction:

Improvebrightness displayVSAvoiddark gradation shielding

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The display function is segmented between two panels: the first panel with high transmittance liquid crystal handles bright gradations, while the second panel with low transmittance liquid crystal handles dark gradation shielding. This segmentation allows each panel to optimize its performance for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the display system (first panel and second panel) are assigned different local qualities - the first panel has high transmittance characteristics optimized for brightness, while the second panel has low transmittance characteristics optimized for dark gradation shielding. Each panel's local quality is tailored to its specific role.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If a low transmittance liquid crystal layer is used, then dark gradations are well shielded, but bright gradations lose intensity

Engineering Contradiction:

Improvedark gradation shieldingVSAvoidbrightness display

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention merges the output of two panels with complementary transmittance characteristics. The first panel provides bright gradation display while the second panel provides dark gradation shielding, and their combined effect achieves both high brightness and excellent contrast simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly improves the contrast ratio, ensuring that the darkest gradations are properly non-displayed, resulting in a more accurate and visually enhanced image representation.

Implementation Method 1

a first liquid crystal panel 12 and a second liquid crystal panel 13. The first liquid crystal panel 12 includes a plurality of first subpixels 21... The second liquid crystal panel 13 includes a plurality of second subpixels 23

Methodology Applied

Scientific EffectLiquid crystal effect: Liquid Crystals

Implementation Method 2

an optical system 18. The optical system 18 projects the first display panel 12 as a virtual image 60

Methodology Applied

Scientific EffectOptical projection: Lens

Data Source

PatentUS11276360B2Display device and mobile body

Publication Date: 2022.03.15 KYOCERA CORP

AI summary

A display device includes a first display panel, a second display panel, and a controller. The first display panel includes a plurality of first subpixels which are aligned in a grid-like layout in an x-direction and a y-direction. The second display panel includes a plurality of second subpixels which are aligned in a grid-like layout along the x-direction and the y-direction at a same pitch as that of the plurality of first sub pixels. The controller controls the plurality of first subpixels and the plurality of second subpixels based on image data. At least one of the first display panel and the second display panel that is arranged on a user side is a transmissive display panel. Each of the plurality of first subpixels is superimposed on any of the plurality of second subpixels in a normal direction of the first display panel.