Display Backlight Segmentation with Partition Plate
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Solution Overview
Problem
In display devices using local dimming technology, particularly in liquid crystal displays, the challenge lies in achieving high definition and contrast while preventing light leakage between segments, which occurs due to the difficulty in setting multiple LEDs in smaller segments and the visibility of single LEDs, leading to non-uniform luminance distribution and light leakage through diffusion sheets.
Innovation Solution
The solution involves a display device with a backlight system where LEDs are divided into segments, with a partition plate made of white PET resin separating the segments and a light guide positioned between the optical sheet group and the partition plate, ensuring that the emitting region of the LED is closer to the optical sheet group than the protective film, and using a color conversion sheet to enhance light utilization, thereby minimizing light leakage to neighboring segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are set in one segment, then luminance uniformity is improved, but the segment area must be large enough to accommodate multiple LEDs
Solution Approach 1:
The patent divides the backlight unit into multiple segments, with each segment containing one LED. This segmentation allows for precise local control of light emission while maintaining small segment sizes. The partition plates create independent light-emitting regions that can be controlled individually, resolving the contradiction between using multiple LEDs per segment and maintaining small segment area.
Solution Approach 2:
The patent introduces a light guide as an intermediary component between the LED and the diffusion sheet. The light guide distributes light from a single LED uniformly across the segment area, eliminating the need to place multiple LEDs in each segment while maintaining luminance uniformity. This intermediary structure allows one LED to serve the function that would otherwise require multiple LEDs.
2Device complexity
If only one LED is set in each segment, then manufacturing complexity is reduced, but luminance uniformity deteriorates and the LED becomes visible from the screen side
Solution Approach 1:
The light guide acts as a mediator that takes light from a single LED and distributes it uniformly across the entire segment. This intermediary structure hides the point-source nature of the single LED while maintaining manufacturing simplicity, thus resolving the contradiction between using one LED and achieving uniform luminance distribution.
Solution Approach 2:
The patent uses a diffusion sheet as a thin film component that further distributes light from the light guide. This thin film structure smooths out luminance variations and hides the LED point source, achieving uniform appearance while maintaining the simple single-LED-per-segment configuration.
3Illumination intensity
If a diffusion sheet is used to improve luminance uniformity, then luminance uniformity is improved, but light leaks to neighboring segments
Solution Approach 1:
The light guide serves as an intermediary that distributes light uniformly within each segment before it reaches the diffusion sheet. By pre-distributing light in the light guide, the diffusion sheet's light-spreading effect is contained within segment boundaries, preventing light leakage to neighboring segments while still achieving luminance uniformity within each segment.
Solution Approach 2:
The partition plates create physically separated light-emitting regions for each segment. This segmentation prevents light diffused by the diffusion sheet from crossing segment boundaries, as the partition plates act as barriers. Thus, the diffusion sheet can be used for uniformity without causing inter-segment light leakage.
4Manufacturing precision
If smaller segment sizes are used for higher definition, then definition is improved, but the ability to set multiple LEDs in one segment is reduced
Solution Approach 1:
The patent adopts a segmentation strategy where each small segment contains exactly one LED. This approach is specifically designed for high-definition displays with small segment sizes, where accommodating multiple LEDs would be impractical. The single-LED-per-segment configuration combined with light guide technology maintains manufacturing feasibility while achieving high definition.
Solution Approach 2:
The light guide intermediary allows a single LED to provide sufficient and uniform illumination for small high-definition segments. This eliminates the need to place multiple LEDs in each small segment, making the manufacturing process feasible while maintaining the small segment sizes required for high definition.
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 effectively reduces light leakage between segments, maintains high contrast, and allows for the use of fewer LEDs, decreasing manufacturing costs while maintaining necessary contrast and definition, even with smaller segment sizes.
Implementation Method 1
the partition plate is made of white PET resin
Implementation Method 2
the partition plate is made of white PET resin
Implementation Method 3
a light guide is disposed between the optical sheet group and the partition plate
Implementation Method 4
the optical sheet group includes a color conversion sheet
Implementation Method 5
the light source substrate, except the LEDs, is covered by a protective film
Data Source
AI summary
The purpose of the present invention is to realize a display device of high definition and high contrast by applying an accurate local dimming. The structure of the invention is as follows. A display device including: a display panel and a back light; in which the back light includes a light source and optical sheet group; the light source includes the light source substrate and LEDs disposed on the light source substrate; the light source is divided into segments in a plan view; at least one of the LEDs is disposed in a segment; the light source substrate, except the LEDs, is covered by a protective film; the segment is partitioned as by wall with the partition plate made of resin; the partition plate is disposed on the protective film.