Display Device Cyan White Light Time-Division Driving
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Solution Overview
Problem
Liquid crystal display (LCD) devices face challenges in achieving high color reproducibility and image quality due to limitations in color gamut, particularly with low cyan color ratios leading to decreased color purity and reproducibility.
Innovation Solution
A display device with a backlight unit comprising multiple light sources and light control layers, where the first light source emits white light and the second light source emits cyan light, with time-division driving to selectively transmit and block these lights to the pixels, allowing for enhanced color gamut representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light source having a cyan color is driven to expand color gamut, then color reproducibility increases in high cyan color ratio images, but color purity decreases in low cyan color ratio images
Solution Approach 1:
The patent employs time-division driving where the cyan light source and white light source are alternately activated in different time periods. During the first time period, the cyan light source drives cyan sub-pixels while the white light source is off. During the second time period, the white light source drives non-cyan sub-pixels while the cyan light source is off. This periodic activation prevents color mixing and maintains color purity across different image content types.
Solution Approach 2:
The system dynamically adjusts which light source activates based on the cyan color ratio requirements of the displayed image content. The control unit determines the appropriate time period and activates the corresponding light source, making the system adaptable to varying color reproduction needs while maintaining optimal color purity for each pixel type.
2Device complexity
If a single white light source is used, then device complexity is low, but color gamut expansion capability is limited
Solution Approach 1:
The backlight unit is segmented into distinct light source modules: a cyan light source module and a white light source module. Each module can be independently controlled and activated. This segmentation allows the system to selectively use different light sources based on the color reproduction requirements, enabling color gamut expansion to the cyan color space while maintaining manageable device complexity through modular architecture.
3Reliability
If additional cyan light source is added to expand color gamut, then color reproducibility improves for cyan-heavy images, but image quality deteriorates due to color breakup
Solution Approach 1:
The patent uses time-division driving where cyan and white light sources are alternately activated in non-overlapping time periods. This prevents simultaneous illumination that would cause color breakup, while still achieving expanded color gamut reproduction for cyan-heavy images by activating the cyan light source during its designated time period.
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
This approach enables improved color reproducibility and image quality by expanding the color gamut, ensuring consistent performance across varying cyan color ratios and preventing color breakup, resulting in a more accurate and vibrant color representation.
Implementation Method 1
the light converting units respectively receiving the first light from the backlight unit through the light control layers of the first, second, and third pixels and converting the received first light into light having different wavelengths
Implementation Method 2
the light control layers of the first, second, and third pixels may transmit the first light to provide the first light to the light converting units, respectively, and the light control layer of the fourth pixel may block the first light
Data Source
AI summary
A display device includes a display panel including a first pixel, a second pixel, a third pixel, and a fourth pixel, and a backlight unit including a first light source emitting a first light and a second light source emitting a second light, the first, second, third, and fourth pixels including respective light control layers and including respective light converting units, the light converting units respectively receiving the first light from the backlight unit through the light control layers of the first, second, and third pixels and converting the received first light into light having different wavelengths, the fourth pixel including a light transmitting unit receiving the second light from the backlight unit through the light control layer of the fourth pixel and transmitting the received second light therethrough.