Linear Light Source for Narrow Frame LCDs
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Solution Overview
Problem
Existing edge-lit planar light emitting devices face challenges in achieving a narrow frame and a small width in the depth direction for liquid crystal displays, as the light source on the side surface of the light guide plate is not adequately minimized.
Innovation Solution
A linear light source configuration is introduced, comprising a light-transmissive base and light emitting devices with a bonding member, where the light-transmissive base and light emitting devices have the same width, allowing for reduced depth and improved light uniformity, and a flexible wiring board is used to maintain mechanical strength without increasing the width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source is disposed on the side surface of the light guide plate to achieve edge-lit configuration, then the light can enter the light guide plate from the side surface, but the width of the light source in the depth direction increases the frame size
Solution Approach 1:
The patent transitions from a conventional planar light source arrangement to a three-dimensional stacked configuration where light emitting devices are vertically arranged above a light-transmissive base. This vertical stacking in the depth direction allows the light source to maintain a small footprint while achieving the required light output, thereby reducing the frame size without compromising illumination intensity.
2Length of moving object
If the light source width in the depth direction is reduced to achieve a narrow frame, then the frame size decreases, but the light uniformity and luminance evenness deteriorate
Solution Approach 1:
The patent divides the light source into multiple discrete light emitting devices (LEDs or mini-LEDs) that are vertically stacked and spatially separated. Each light emitting device acts as an independent light source, and their collective arrangement creates a linear light source with uniform light distribution. This segmentation allows the system to maintain narrow frame dimensions while achieving luminance uniformity through the distributed light emission pattern.
Solution Approach 2:
The patent employs different optical characteristics at different locations within the light source structure. The light-transmissive base has specific optical properties to guide and distribute light, while the light emitting devices are positioned at optimized locations to ensure uniform illumination. This local optimization of optical properties maintains luminance uniformity even with reduced overall width.
3Length of moving object
If multiple light emitting devices are stacked vertically to reduce the depth width, then the frame becomes narrower, but the structural stability and mechanical strength may be compromised
Solution Approach 1:
The patent implements a nested structure where light emitting devices are vertically stacked and integrated within the light-transmissive base. The light-transmissive base serves as both the structural support and the light guiding medium, providing mechanical strength while accommodating the vertically arranged light emitting devices. This nested configuration maintains structural integrity while achieving the narrow frame profile.
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 results in a thinned planar light emitting device with reduced luminance and color unevenness, enabling a liquid crystal display with a narrower frame while maintaining high light output and uniformity.
Implementation Method 1
a light-transmissive member disposed on a light emitting surface side of the light emitting element
Implementation Method 2
a first bonding member that bonds the first main surface of the light-transmissive base and the upper surface of the light emitting device
Data Source
AI summary
Provided is a linear light source including: a light-transmissive base having a first main surface that has a rectangular shape with long sides and short sides, a second main surface located opposite to the first main surface, a first (long) side surface, and a second (short) side surface; a plurality of light emitting devices, each including a light emitting element, a light-transmissive member and a sealing member. An upper surface of each of the light emitting devices includes an upper surface of the light-transmissive member. A first bonding member bonds the first main surface of the light-transmissive base and the upper surfaces of the light emitting devices. A width of the light-transmissive base is the same as a width of the light emitting devices in a first direction orthogonal to a first side surface of the light-transmissive base.