Backlight Unit Optical Film Reflects Light for Slim LCD
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Solution Overview
Problem
Existing slim LCD devices face limitations in reducing thickness without compromising light incident efficiency due to the conventional design of the light guide panel and light source arrangement.
Innovation Solution
A backlight unit design featuring a light guide panel with an optical film that reflects vertically-incident light at a certain angle and an optical sheet part that changes the light travel direction to be vertical to the panel, combined with a light source unit positioned at the rear-direction lower end of the light guide panel, enhancing light distribution and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the light guide panel is reduced to manufacture a slim LCD device, then the device thickness is reduced, but the light incident efficiency is reduced
Solution Approach 1:
A reflector is introduced as an intermediary component between the light guide panel and the light source. The reflector captures light that would otherwise be lost and redirects it into the light guide panel, thereby maintaining high light incident efficiency even when the light guide panel thickness is reduced for a slim device profile.
Solution Approach 2:
The solution addresses the light incident efficiency problem not by increasing the panel thickness (one dimension), but by adding a reflector component that operates in a different spatial dimension - capturing and redirecting light from the rear side of the light guide panel, thus improving efficiency without compromising device slimness.
2Loss of energy
If the thickness of the light guide panel is formed identically to the width of the light source to maintain high light incident efficiency, then the light incident efficiency is high, but the device cannot be manufactured in a slim type
Solution Approach 1:
The lighting system is segmented into distinct functional components: the light source unit, the light guide panel, and the reflector. This segmentation allows each component to be optimized independently - the light guide panel can be made thin for device slimness while the reflector compensates for any light loss, resolving the contradiction between thickness and efficiency.
Solution Approach 2:
The reflector serves as a mediating element that decouples the relationship between light guide panel thickness and light incident efficiency. By introducing this intermediate component, the system can achieve high efficiency regardless of the light guide panel thickness, enabling both slim device design and high light utilization.
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 allows for a slimmed-down LCD device thickness without reducing light efficiency, as most light is effectively directed onto the liquid crystal panel, maintaining high incident efficiency.
Implementation Method 1
an optical film disposed in a front direction of the light guide panel to face the light source unit, and configured to reflect light emitted from the light source unit
Implementation Method 2
an optical sheet part disposed in the front direction of the light guide panel, and configured to change a travel direction of the light, which is output from the light guide panel, to a direction vertical to the light guide panel
Data Source
AI summary
A backlight unit and an LCD device using the same are provided. The backlight unit includes a light guide panel, a light source unit disposed at a rear-direction lower end of the light guide panel, an optical film disposed in a front direction of the light guide panel to face the light source unit and configured to reflect light emitted from the light source unit, and an optical sheet part disposed in the front direction of the light guide panel, and configured to change a travel direction of the light, which is output from the light guide panel, to a direction vertical to the light guide panel.