Dichroic Filter for Quantum Dot Display Contrast
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Solution Overview
Problem
Display apparatuses with quantum dot color filters face a decrease in contrast ratio due to higher black transmittance on the lateral side compared to the front side, and the diffusing nature of quantum dots leads to reduced luminance contrast.
Innovation Solution
Incorporating a dichroic filter and additional dichroic filters strategically within the light guide plate and optical sheet configuration to concentrate light emitted from the source, combined with a prism sheet and polarizer, to enhance light concentration and maintain contrast ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If quantum dot material is used to replace color filters, then light conversion efficiency is improved and lateral visibility is enhanced, but contrast ratio is decreased due to higher black transmittance on lateral side
Solution Approach 1:
A dichroic filter is introduced as an intermediary component between the light guide plate and the display panel. This filter selectively transmits light in specific directions while blocking light from other directions, thereby reducing lateral light leakage and improving contrast ratio without compromising the light conversion efficiency of the quantum dot material
2Ease of operation
If quantum dot material is used to replace color filters, then lateral visibility is improved through light diffusion, but contrast ratio is decreased due to light diffusing in all directions
Solution Approach 1:
The dichroic filter is designed with directionally selective optical properties, allowing it to differentiate between light coming from different directions. It permits light diffusion for lateral visibility while simultaneously blocking lateral light leakage that degrades contrast ratio, thus applying different optical qualities to different directions of light propagation
3Reliability
If additional dichroic filters are added to concentrate light, then contrast ratio is improved, but device complexity increases
Solution Approach 1:
The dichroic filter's optical parameters (transmission wavelength range, angular selectivity) are optimized to achieve effective light concentration and contrast ratio improvement with a single filter layer, avoiding the need for multiple filters and reducing overall device complexity while maintaining performance
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 effectively improves the contrast ratio by concentrating light on the front surface, reducing the difference in brightness between the front and side surfaces, thereby enhancing the display's overall luminance contrast.
Implementation Method 1
a dichroic filter provided on a first side the light guide plate that is opposite to a second side of the light guide plate on which the display panel is provided, the dichroic filter being configured to concentrate the light emitted from the light source
Implementation Method 2
a prism sheet disposed between the light guide plate and the display panel, and configured to refract light transmitted from the light emitting surface of the light guide plate
Implementation Method 3
a polarizer disposed between the liquid crystal layer and the prism sheet, and configured to polarize light passing through the prism sheet
Implementation Method 4
When each of the above-described color filters is replaced with a quantum dot material that converts a color of light into a specific color
Data Source
AI summary
A display apparatus including a dichroic filter is provided. The display apparatus includes a display panel including a liquid crystal layer and a quantum dot color filter disposed on the liquid crystal layer; a light source configured to emit light; a light guide plate configured to guide the light emitted from the light source towards the display panel; and a dichroic filter provided on a first side the light guide plate that is opposite to a second side of the light guide plate on which the display panel is provided, the dichroic filter being configured to concentrate the light emitted from the light source.