Quantum Dot Backlight Layout to Eliminate LED Blue Hotspots
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Solution Overview
Problem
The increasing space between LEDs in backlight modules for LCD displays leads to blue light emission issues, resulting in a bluish effect directly above the light emitting devices due to incomplete excitation of quantum dot materials by unabsorbed blue light.
Innovation Solution
A fluorescent layer is strategically placed in the orthographic projection area of the light emitting device on the circuit board to absorb and excite white light, reducing the intensity of reflected blue light and ensuring proper excitation of quantum dot materials, thereby eliminating the bluish effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the number of LEDs and films is reduced to lower production cost, then the production cost is reduced, but the space between LEDs increases causing blue light emission from the backlight module
Solution Approach 1:
The patent converts the harmful blue light emission from LED positions into a beneficial effect by placing fluorescent layers that absorb the blue light and emit yellow light, which then excites the quantum dot film to produce red and green light. This transforms the problematic blue light leakage into a useful excitation source for the quantum dots, achieving both cost reduction and blue light elimination.
Solution Approach 2:
The patent introduces fluorescent layers as intermediary elements between the LEDs and the quantum dot film. These fluorescent layers act as mediators that absorb blue light from LEDs and convert it to yellow light, which then serves as the excitation source for the quantum dot film. This intermediary solution allows for reduced LED density while preventing blue light emission.
2Quantity of substance
If the space between LEDs is increased to reduce the number of LEDs, then the production cost is lowered, but the blue light emission from backlight module increases
Solution Approach 1:
The patent converts the harmful blue light emission that results from increased LED spacing into a beneficial excitation source. By placing fluorescent layers at LED positions, the blue light that would otherwise be emitted is instead used to excite the fluorescent material, which then emits yellow light to excite the quantum dot film, eliminating blue light leakage while maintaining reduced LED density.
Solution Approach 2:
The patent applies local quality by placing fluorescent layers specifically at the positions where LEDs are located, rather than uniformly across the entire backlight module. This localized approach allows the fluorescent layers to convert blue light at the source positions, effectively addressing blue light emission only where it occurs due to increased LED spacing.
3Device complexity
If blue light is emitted from backlight module at LED positions, then the backlight structure can be simplified with fewer LEDs, but the bluish effect appears directly above the light emitting devices
Solution Approach 1:
The patent converts the harmful bluish effect into a beneficial process by using the blue light emission as the excitation source for fluorescent layers. The fluorescent layers absorb the blue light and emit yellow light, which then excites the quantum dot film to produce red and green light. This transforms the problematic bluish effect into a useful multi-color light generation process, simplifying the backlight structure while eliminating the bluish appearance.
Solution Approach 2:
The patent uses composite materials by combining fluorescent materials with quantum dot materials in a layered structure. The fluorescent layer (containing yellow phosphors) and quantum dot film (containing red and green quantum dots) work together as a composite system to convert blue light into full-spectrum white light, eliminating the bluish effect while maintaining structural simplicity.
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 addresses the bluish issue by ensuring that the quantum dot materials receive sufficient excitation light, resulting in improved backlight quality and reduced blue light emission directly above the light emitting devices.
Implementation Method 1
a fluorescent layer is provided in an orthographic projection area of the light emitting device on the circuit board, and the fluorescent layer is configured to absorb light emitted from the light emitting device to excite white light
Implementation Method 2
the backlight module can facilitate the display with high color gamut and high image quality by combining the blue LED and the QD film
Data Source
AI summary
A display apparatus, including: a backlight module and a panel. The backlight module includes: a circuit board, a light-emitting device, and a quantum dot film layer; a fluorescent layer is provided in an orthographic projection area of the light-emitting device on the circuit board, and the fluorescent layer can absorb incident light and excite white light. When light emitted from the light-emitting device is incident onto the orthographic projection area, the fluorescent layer may first excite white light using a portion of the light, so that the intensity of light reflected to the quantum dot film layer is relatively weakened to just meet requirements of a quantum dot material on saturation of excited light, and the excited light of the quantum dot material and unexcited blue light may be mixed into white light which provides white backlight for the panel together with the white light excited by the fluorescent layer.