Side-Lit LCD Backlight with Variable LED Spacing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices for large applications like TVs face challenges in reducing thickness and weight, making them unsuitable for wall-hanging due to the bulkiness and weight of cold cathode fluorescent lamp backlights, which require large inverter circuits and increase the device's thickness and weight.
Innovation Solution
A liquid crystal display device design featuring a light guide panel with LEDs on its sides, housed in a mold with flexible wiring substrates and specific optical components, where the distance between LEDs varies to ensure uniform brightness and reduce thickness, and the thermal expansion coefficients of materials are managed to prevent deformation and ensure proper light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a direct-type backlight with cold cathode fluorescent lamps is used under the liquid crystal display panel, then screen brightness is increased, but device thickness increases
Solution Approach 1:
The patent transitions from a direct-type backlight (light source directly under the panel) to a side light system (light sources positioned at the edges). This spatial reconfiguration allows light to enter the light guide panel from the sides and be distributed across the display area, achieving adequate brightness while significantly reducing the thickness required under the panel.
Solution Approach 2:
The light guide panel serves as an intermediary component that receives light from the cold cathode fluorescent lamps positioned at its edges and distributes it uniformly across the display area. This mediator enables the separation of the light source from the light emission area, allowing thin panel construction while maintaining brightness.
2Length of stationary object
If cold cathode fluorescent lamps are used on the sides of the light guide panel, then device thickness is reduced, but device weight increases due to the inverter circuit
Solution Approach 1:
The patent specifies precise spacing parameters for the cold cathode fluorescent lamps along the edges of the light guide panel. By optimizing the pitch and positioning of multiple lamps, the system achieves uniform light distribution across the display area, reducing the need for excessive lamp power and associated inverter circuitry weight.
3Length of stationary object
If cold cathode fluorescent lamps are provided on the four sides of the light guide panel, then device thickness is reduced, but screen brightness uniformity deteriorates
Solution Approach 1:
The patent implements non-uniform spacing of cold cathode fluorescent lamps along the edges of the light guide panel. The pitch between adjacent lamps is varied depending on position, with closer spacing in regions requiring more light and wider spacing where less light is needed. This local optimization compensates for the natural light distribution patterns and achieves uniform overall brightness across the display area.
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 thinner, lighter liquid crystal display device with uniform screen brightness, allowing for easier wall-hanging without the need for extensive mounting efforts, while maintaining efficient light distribution and preventing brightness irregularities.
Implementation Method 1
The backlight includes a light guide panel with plural light emitting diodes provided on each of four side portions of the light guide panel
Implementation Method 2
a light guide panel with plural light emitting diodes provided on each of four side portions of the light guide panel
Data Source
AI summary
In order to achieve a liquid crystal display device for TV with a reduced thickness, light weight, and uniform brightness, a liquid crystal display panel and a backlight are housed in a mold. In the backlight, light emitting diodes are provided in a frame-like flexible wiring substrate, in which plural the light emitting diodes are provided on each of four side surfaces of a light guide panel. A distance between the light emitting diodes in the central portion of each side of the light guide panel is small, while a distance in the corners of each side is large.