LCD Backlight Color Control for Dynamic Range and Blur Reduction
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Solution Overview
Problem
Conventional liquid crystal display (LCD) apparatuses face challenges in achieving a wide dynamic range, vivid color representation, and clear moving images due to slow response times and the 'holding type' display system, which results in after-image phenomena and blurriness.
Innovation Solution
An LCD apparatus with a controller that adjusts display data and backlight luminance for each color based on input video signals and ambient light, using a backlight unit with independent control of red, green, and blue light-emitting diodes to optimize light emission and reduce unnecessary light, thereby expanding the dynamic range and color gamut while minimizing blur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a holding type display system is used to continuously display images during one frame period, then the display system is simple and stable, but the image becomes vague and blurry when displaying moving images
Solution Approach 1:
The patent applies dynamics by making the backlight unit's light emission controllable and variable over time. Instead of continuous static illumination, the backlight now dynamically adjusts its luminance and emission timing to match the display content, enabling clear moving image display while maintaining system stability through controlled temporal variation.
Solution Approach 2:
The patent implements periodic action by synchronizing the backlight unit's light emission with the frame period of the display system. The backlight emits light in periodic intervals corresponding to frame updates, which eliminates the blur caused by continuous illumination while maintaining stable periodic operation of the display system.
2Stability of the object's composition
If the LCD response time is slow (10-30 milliseconds), then the liquid crystal material is stable and easy to control, but after-image phenomena occur and moving images become blurry
Solution Approach 1:
The patent applies preliminary action by having the backlight unit start emitting light before the LCD completes its response and continue emitting after the response is complete. This temporal extension of backlight emission compensates for the slow LCD response, ensuring that the displayed image is visible throughout the entire frame period without after-image phenomena, while the LCD itself maintains its stable slow response characteristics.
3Manufacturing precision
If a feedback circuit is added to adjust luminous period of each color LED, then color representation is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the backlight unit into multiple independently controllable color channels (red, green, blue LEDs). Each color channel can be controlled separately with different luminance and timing, enabling precise color representation. This segmentation allows independent optimization of each color channel without requiring complex inter-channel coordination circuits.
Solution Approach 2:
The patent implements parameter changes by independently adjusting the luminance and emission timing parameters of each color LED channel. By varying these parameters based on display content requirements, the system achieves accurate color representation and optimized image quality without needing complex feedback circuits, as the parameters can be directly controlled from the display data.
4Illumination intensity
If unnecessary light from the backlight unit is not reduced, then the backlight provides sufficient illumination, but the dynamic range is limited and color gamut is reduced
Solution Approach 1:
The patent applies local quality by controlling the luminance of each color LED channel independently according to the local requirements of the displayed image content. Instead of uniform illumination, the backlight provides targeted illumination in specific color channels and time intervals, which expands the dynamic range and color gamut while maintaining sufficient overall illumination through intelligent distribution of light across different channels.
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 enhances image quality by providing a wider dynamic range, improved color representation, and reduced blur in moving images, resulting in a more vivid and clear display suitable for various lighting environments.
Implementation Method 1
a liquid crystal layer laid between the pair of substrates
Implementation Method 2
a plurality of electrode groups for applying an electric field onto the liquid crystal layer
Implementation Method 3
a backlight unit having a capability of controlling a ray of light of each of three or more colors, for applying a ray of light onto an LCD
Implementation Method 4
an LED (Light-emitting Diode) is used as the backlight unit
Data Source
AI summary
The liquid crystal display apparatus includes a liquid crystal display, a backlight unit for emitting rays of light of three or more colors, the ray of each color being controlled, and applying these rays of light onto the liquid crystal display. A controller is further provided for controlling a change of display data of each color of the liquid crystal display and an emitted light quantity of each color of the backlight unit at a time, based on a video signal being inputted for displaying the corresponding image and an output signal sent from an ambient light sensor for sensing ambient light.