Direct-Type Backlight Unit With Light Guide Plate for Thin HDR Displays
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Solution Overview
Problem
Liquid crystal displays with edge type backlight units cannot achieve high dynamic range (HDR) imaging due to limitations in luminance uniformity across the display screen, and the use of lenses in direct type backlight units hinders thickness reduction.
Innovation Solution
A display apparatus employing a direct type backlight unit with a light guide plate featuring light source grooves and a reflection sheet, which spreads light laterally without the need for a separate lens, improving luminance uniformity and reducing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a lens is used in a direct type backlight unit to spread light laterally, then uniformity of surface light is improved, but the thickness of the display apparatus increases
Solution Approach 1:
The patent extracts and eliminates the lens component from the backlight unit. Instead of using a lens to spread light laterally, the invention uses a direct type backlight structure where light emitting diodes are directly coupled to the light guide plate, removing the thickness contribution of the lens while maintaining light uniformity through alternative optical design
Solution Approach 2:
The patent introduces a light guide plate as an intermediary component that directly receives light from the light emitting diodes and distributes it across the display area. The light guide plate serves as the mediator between the light source and the display panel, eliminating the need for a separate lens component
2Length of moving object
If an edge type backlight unit is used to reduce thickness, then the thickness of the display apparatus is reduced, but the ability to achieve HDR imaging and luminance uniformity is lost
Solution Approach 1:
The patent inverts the conventional backlight approach by using a direct type backlight structure instead of an edge type. Rather than placing light sources at the edges and using complex light guiding mechanisms, the invention places light emitting diodes directly behind the light guide plate, fundamentally changing the light distribution approach to achieve both thinness and uniformity
Solution Approach 2:
The patent changes the spatial arrangement parameter of the light sources, transitioning from edge-mounted LEDs to centrally positioned LEDs directly coupled to the light guide plate. This parameter change enables the system to achieve both reduced thickness and improved luminance uniformity simultaneously
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 enables the display apparatus to achieve HDR imaging while minimizing thickness by uniformly distributing light across the screen through the light guide plate and reflection sheet, eliminating the need for a separate lens.
Implementation Method 1
light emitted from each of the light emitting diodes enters the corresponding light source groove
Implementation Method 2
light guide plate disposed between the frame and the optical part to cover the plurality of light emitting diodes
Implementation Method 3
a reflection sheet, which spreads light laterally without the need for a separate lens
Data Source
AI summary
A display apparatus including a frame, light emitting diode chips separated from each other and regularly arranged in a matrix on the frame, an optical part including a display panel and at least one of a phosphor sheet and an optical sheet, a light guide plate disposed between the frame and the optical part to cover the light emitting diode chips, at least one reflector disposed between the frame and the light guide plate to reflect at least part of light emitted from the light emitting diode chip to direct at least part of light emitted therefrom to the light guide plate, and a first-type electrode and a second-type electrode, in which at least one of the light emitting diode chips is a flip-chip type and includes a first-type semiconductor layer electrically connected to the first-type electrode and a second-type semiconductor layer electrically connected to the second-type electrode.