LED Backlight Package Structure for Uniform Thin LCD Illumination
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Solution Overview
Problem
Direct-lighting type backlight units face challenges in achieving uniform light distribution and thin thickness due to the need for dense LED arrangements and the use of diffusion lenses, which can hinder local dimming and result in low luminous uniformity and bright spots.
Innovation Solution
The implementation of a light emitting device with a light emitting diode chip, a light reflection member on its upper surface, and a light blocking member on its side surface, along with a dam on the circuit board to manage light emission, allowing for independent operation of LEDs and reducing the thickness of the backlight unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple light emitting diodes are arranged in a matrix below the display panel to achieve uniform light distribution, then luminous uniformity is improved, but the thickness of the backlight unit increases and device complexity increases
Solution Approach 1:
The patent transitions from a planar matrix arrangement of LEDs to a three-dimensional stacked configuration where multiple LED layers are vertically arranged. This dimensional change allows light to be emitted from multiple levels, improving luminous uniformity across the display panel while maintaining a compact overall thickness through vertical integration rather than horizontal expansion.
Solution Approach 2:
The patent implements a nested structure where multiple LED layers are stacked one above another, with each layer containing multiple LEDs. The layers are arranged in a nested configuration where inner layers are surrounded by outer layers, allowing efficient space utilization and uniform light distribution from multiple concentric rings of LEDs at different heights.
2Illumination intensity
If a diffusion lens is used to spread light from light emitting diodes, then luminous uniformity is improved, but the thickness of the backlight unit increases
Solution Approach 1:
The patent extracts and removes the diffusion lens component from the backlight unit design. Instead of using a diffusion lens to spread light, the invention relies on the inherent light-emitting properties of the stacked LED array and the reflective properties of the light guide plate to achieve uniform light distribution, thereby eliminating the thickness contribution of the diffusion lens.
Solution Approach 2:
The patent replaces the mechanical diffusion lens system with an optical system based on stacked LEDs and a light guide plate. The light guide plate uses total internal reflection and optical scattering properties to distribute light uniformly across the display panel, substituting the need for a physical diffusion lens and reducing overall thickness.
3Length of stationary object
If light emitting diodes are positioned close to the display panel to reduce thickness, then the thickness of the backlight unit is reduced, but uniform light distribution becomes difficult to achieve
Solution Approach 1:
The patent uses vertical stacking of multiple LED layers to create a three-dimensional light source distribution. By arranging LEDs at different heights along the vertical axis, the system achieves uniform light distribution across the display panel surface without requiring large horizontal spacing, thus maintaining thin profile while improving luminous uniformity.
Solution Approach 2:
The patent segments the light source into multiple independent LED layers, each contributing to the overall light distribution. This segmentation allows each layer to be optimized for specific lighting requirements and enables the light to be distributed more uniformly across the display panel through the combined effect of multiple segmented sources at different vertical positions.
4Device complexity
If the region covered by one light emitting diode is increased to reduce the number of LEDs, then device complexity is reduced, but local dimming capability is hindered
Solution Approach 1:
The patent segments the backlight system into multiple independently controllable LED layers, with each layer containing multiple LEDs arranged in specific patterns. This segmentation creates numerous small controllable regions that can be individually dimmed or adjusted, enabling precise local dimming functionality while maintaining a manageable overall device structure through modular layer design.
Solution Approach 2:
The patent implements dynamic control capabilities where each LED layer and individual LEDs within layers can be independently adjusted in brightness and activation state. This dynamic controllability allows the system to adapt to different display requirements,实现局部调光 (local dimming) by selectively adjusting specific regions while maintaining overall system simplicity through standardized layer structures.
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 configuration enhances luminous uniformity, supports local dimming, and maintains a thin profile for the backlight unit, improving contrast ratio and reducing power consumption.
Implementation Method 1
a light reflection member disposed on an upper surface of the light emitting diode chip
Implementation Method 2
a light transmitting resin covering at least a side surface of the light emitting diode chip
Implementation Method 3
a light blocking member covering an upper surface of the light transmitting resin
Data Source
AI summary
A display apparatus including a display panel, and a backlight to provide light toward the display panel, the backlight including a circuit board, an optical layer disposed on the circuit board, at least one light emitter disposed between the circuit board and the optical layer and including a light emitting structure disposed on the circuit board and having first and second conductivity type semiconductor layers and an active layer therebetween, first and second electrode pads electrically connected to the first and second conductivity type semiconductor layers, respectively, a reflector on the light emitting structure, a light transmitting layer disposed on the circuit board and contacting the light emitter, and a dam disposed on the circuit board and surrounding the light emitter and including a portion having a curved shape.