Display Device Color Separation Diffraction Grating

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Solution Overview

Problem

Conventional display devices suffer from angle dependency issues with color and brightness, as light separation by color separation devices leads to light being diffused into different angle directions, resulting in inconsistent color and brightness across viewing angles, and existing solutions either increase costs or reduce brightness.

Innovation Solution

A display device structure featuring a color separation device with periodically arranged elements that diffract light of different wavelengths to specific directions, eliminating the need for optical parts to concentrate light in a specific direction, thereby maintaining consistent brightness across angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a color separation device including a prism and lens is used to separate backlight light into wavelengths, then light efficiency is improved, but angle dependency of color and brightness occurs

Engineering Contradiction:

Improvebacklight light efficiencyVSAvoidcolor and brightness consistency

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The invention divides the backlight unit into multiple independent light sources (first, second, and third backlight units) corresponding to different wavelength ranges (blue, green, red). Each backlight unit independently illuminates its corresponding color filter, eliminating the need for a single color separation device that causes angle dependency. This segmentation approach maintains both high light efficiency and consistent color/brightness across viewing angles.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies different characteristics to different parts of the display system by using specialized backlight units for each color region. Each backlight unit is optimized for its specific wavelength range and positioned to illuminate only its corresponding color filter, creating local optimization that prevents cross-interference and angle dependency issues.

Inventive Principle:

Principle #3Local quality

2Reliability

If optical parts (Fresnel lens and prism) are disposed above and below each pixel to concentrate light, then angle dependency is reduced, but device complexity and cost increase

Engineering Contradiction:

Improveviewing angle consistencyVSAvoidoptical parts quantity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and removes the complex optical concentration parts (Fresnel lenses, prisms) from the system entirely. Instead of adding these components to concentrate light, the invention uses the natural emission characteristics of LED backlight units combined with strategic positioning and color separation through filters to achieve uniform viewing angles without additional optical concentration components.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If a diffusion plate of strong Haze is disposed to ease angle shift, then viewing angle is improved, but brightness of front side decreases significantly

Engineering Contradiction:

Improveviewing angle uniformityVSAvoidfront side brightness

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The invention segments the backlight system into multiple wavelength-specific units, allowing each to maintain its light intensity without requiring a strong haze diffusion plate. By separating the light sources by color and position, the system achieves wide viewing angles through geometric arrangement rather than diffuse scattering, preserving front-side brightness.

Inventive Principle:

Principle #1Segmentation

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 ensures consistent brightness and color distribution across various viewing angles without the need for costly optical parts, improving the display's efficiency and reducing brightness loss.

Implementation Method 1

a color separation device including, for example, a prism (diffraction grating) and a lens is used to efficiently use the backlight light. With the color separation device, the backlight light is separated into wavelengths of red, green, and blue

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

a color filter (CF) including filter elements corresponding to red, green, and blue (RGB) is used. In a display device with such a color filter, white light emitted from a backlight (backlight light) enters an RGB color filter arranged for each pixel and light of red, green, and blue is absorbed in each color filter

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS11243426B2Display device, display method, and color separation device

Publication Date: 2022.02.08 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a display device includes a first arrangement layer and a second arrangement layer. The first layer includes a first pixel, a second pixel, and a third pixel are arranged periodically in one direction. The second layer is opposed to the first layer, and the second layer includes a first element, a second element, and a third element which are arranged periodically to correspond to the first pixel, the second pixel, and the third pixel, respectively, and separate emission light to light of wavelength corresponding to a first color, light of wavelength corresponding to a second color, and light of wavelength corresponding to a third color to be emitted on the first pixel, the second pixel, and the third pixel, respectively.