Backlight Unit with White and Blue Light Sources
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Solution Overview
Problem
Conventional LCD display apparatuses using white LEDs with YAG fluorescent substances can only express about 75% of the NTSC color region, leading to reduced brightness and color breakup issues due to differences in brightness and wavelength characteristics of R, G, B light sources over time.
Innovation Solution
A display apparatus utilizing a backlight unit with both white and blue light sources, where the white light source is combined with a fluorescent substance on a blue LED, and the blue light source is used to express all R, G, B colors, allowing for independent control of the light sources to enhance brightness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a white LED with YAG fluorescent substance is used, then the display can provide white light, but only about 75% of NTSC color region can be expressed
Solution Approach 1:
The patent divides the backlight system into separate white light source and blue light source components, allowing independent control of each. This segmentation enables the system to selectively activate specific light sources based on the color frame being displayed, thereby achieving full NTSC color coverage while maintaining brightness.
Solution Approach 2:
The patent implements dynamic control of the backlight unit by sequentially activating the white light source and blue light source based on the color frame data being scanned. This dynamic switching allows the system to adapt to different color requirements in real-time, achieving both full color region coverage and high brightness.
2Manufacturing precision
If R, G, B light sources are turned on consecutively using FSC method, then color can be embodied, but color breakup phenomenon occurs
Solution Approach 1:
The patent merges the white light source and blue light source in the backlight unit, allowing them to operate simultaneously or sequentially. This combination enables the system to express full color while avoiding the color breakup phenomenon by controlling the backlight to match the panel's color frame scanning.
Solution Approach 2:
The patent implements feedback control by synchronizing the backlight unit operation with the panel driver's color frame scanning. The controller receives color frame data and adjusts the backlight light sources accordingly, ensuring that the backlight remains stable and prevents color breakup while maintaining accurate color expression.
3Manufacturing precision
If R, G, B light sources are used, then color can be expressed, but brightness is reduced due to sub pixel structure limitations
Solution Approach 1:
The patent makes the backlight unit multi-functional by incorporating both white light source and blue light source, allowing it to serve different purposes: the white light source provides overall illumination and works with RGB subpixels, while the blue light source enhances color saturation and works specifically with the blue subpixel. This multi-functionality resolves the brightness reduction issue while maintaining full color expression.
4Illumination intensity
If white LED with YAG fluorescent substance is used, then white light can be provided, but color region coverage is limited to 75% of NTSC
Solution Approach 1:
The patent uses a composite lighting approach by combining white LED with YAG fluorescent substance and blue LED in the backlight unit. This composite system leverages the strengths of each light source: the white LED provides efficient white light illumination, while the blue LED extends the color region coverage to achieve full NTSC compliance, resolving the contradiction between brightness and color coverage.
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 solution enables the display of a full 100% NTSC color region with improved brightness and reduced color breakup, maintaining color accuracy over time by using a white sub pixel and blue LEDs to enhance the R, G, B sub pixel structure.
Implementation Method 1
a backlight unit which provides backlight to the panel unit using a white light source and a blue light source
Implementation Method 2
The white light source may be a plurality of white LEDs where a fluorescent substance is combined on a blue LED
Data Source
AI summary
A display apparatus is disclosed. The display apparatus includes a panel unit which comprises a plurality of sub pixels having different colors; a backlight unit which provides backlight to the panel unit using a white light source and a blue light source; an image processing unit which converts image data into first color frame data and second color frame data; a panel driving unit which turns on a first color sub pixel according to the first color frame data, and which turns on a second color sub pixel according to the second color frame data; a backlight driving unit for driving the backlight unit; and a control unit which controls the backlight driving unit to consecutively turn on the white light source and the blue light source according to operations of the panel driving unit. Accordingly, brightness may be enhanced.