Backlight Assembly Uniform Brightness via Edge Lamp
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Solution Overview
Problem
Direct-type backlight assemblies for large-size liquid crystal displays face challenges in uniformly distributing brightness across the entire display region due to insufficient light diffusion when the distance between lamps and the diffusion plate is reduced, leading to varying brightness levels.
Innovation Solution
A backlight assembly incorporating a light guide plate with a light guide pattern, along with an edge-type lamp positioned at the side of the light guide plate, which outputs light to the exterior, ensuring uniform brightness distribution across the display region, and optionally omitting the diffusion plate or optical sheets to reduce volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the lamps and the diffusion plate is reduced to reduce the volume of the liquid crystal display, then the thickness of the liquid crystal display is reduced, but the light emitted from the lamps is not sufficiently diffused, causing brightness to vary depending on regions
Solution Approach 1:
The backlight assembly is segmented into two types of light sources: direct-type lamps positioned above the light guide plate and an edge-type lamp positioned at the side portion. This segmentation allows each light source to serve a specific function - the direct-type lamps provide overall illumination while the edge-type lamp specifically addresses the brightness deficiency between lamps through the light guide pattern, thereby achieving uniform brightness distribution without requiring a large distance for light diffusion.
Solution Approach 2:
The light guide plate acts as an intermediary element between the edge-type lamp and the display region. It receives light from the edge-type lamp at its side portion and guides this light through the light guide pattern to the exterior, effectively distributing light to regions that would otherwise be dark between the direct-type lamps. This intermediary mechanism enables uniform brightness without needing to increase the distance between lamps and diffusion plate.
2Length of stationary object
If the distance between the lamps and the diffusion plate is reduced to reduce the thickness of the liquid crystal display, then the thickness is reduced, but light diffusion is insufficient leading to non-uniform brightness distribution
Solution Approach 1:
The backlight system is divided into direct-type lamps for general illumination and an edge-type lamp for targeted light supplementation between lamps. This segmentation enables the system to maintain thin thickness while achieving uniform brightness, as the edge-type lamp compensates for the reduced light diffusion distance through the light guide plate's light guiding function.
Solution Approach 2:
Instead of relying solely on vertical light diffusion from above (one-dimensional approach), the invention introduces light from the horizontal dimension through the edge-type lamp positioned at the side portion of the light guide plate. This multi-dimensional light introduction enables effective light distribution even when the vertical distance is minimized, thus reducing display thickness while maintaining brightness uniformity.
3Area of stationary object
If direct-type lamps are used to illuminate the liquid crystal panel, then the backlight assembly can be designed for large-size displays, but the brightness between adjacent lamps is insufficient and varies by region
Solution Approach 1:
The illumination system is segmented into direct-type lamps providing area-wide coverage and an edge-type lamp providing targeted illumination between lamps. This segmentation allows the system to maintain large coverage area while specifically addressing the brightness deficiency in inter-lamp regions through the light guide plate's light guiding capability.
Solution Approach 2:
The invention merges two different lighting approaches - direct illumination from above and edge illumination from the side - into a single backlight assembly. The direct-type lamps and edge-type lamp work together, with the light guide plate mediating the edge light distribution, to achieve both large coverage area and uniform brightness distribution that neither approach could achieve alone.
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 achieves uniform brightness distribution across the entire light receiving region, improving brightness between direct-type lamps and reducing the overall volume of the backlight assembly by increasing the amount of light guided by the edge-type lamp, even without the diffusion plate or optical sheets.
Implementation Method 1
The light guide plate is provided above the first light source and has a first region corresponding to a position of the first light source and a second region corresponding to a space between two adjacent first light sources. The light guide pattern is positioned on the light guide plate at the second region to output the light emitted from the second light source to an exterior of the light guide plate.
Data Source
AI summary
A backlight assembly including direct-type lamps and an edge-type lamp and a liquid crystal display having the backlight assembly. The direct-type lamps are arranged with a predetermined interval to emit light, and the edge-type lamp is provided at a side portion of a light guide plate provided above or below the direct-type lamps. The light guide plate and a light guide pattern output light, which is emitted from the edge-type lamp, through a space between two adjacent direct-type lamps. The backlight assembly supplies light to the light receiving region such that brightness is uniformly distributed throughout the light receiving region regardless of the position of the direct-type lamps.