Backlight Unit Light-Modifying Portion Color Uniformity
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Solution Overview
Problem
Current display devices face challenges in achieving high optical efficiency and uniform image quality, particularly in lightweight and low-power consumption devices like smartphones and tablets, due to brightness deviations and color differences between the peripheral and central areas caused by light emission patterns.
Innovation Solution
A backlight unit design incorporating a substrate with light-emitting devices, a phosphor film, and a light-modifying portion that modifies the color of emitted light to match the phosphor film's color, along with a light-modifying sheet with patterns that scatter, reflect, or diffract light to reduce brightness deviations and enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a direct-type backlight unit with LED light sources is used, then light efficiency and color reproducibility are improved, but brightness deviations and color differences between peripheral and central areas occur
Solution Approach 1:
The patent applies local quality by placing light-modifying portions at specific locations (peripheral areas) of the backlight unit. These light-modifying portions have different optical properties from the central area, specifically designed to adjust the color temperature of peripheral light to match the central area, thereby resolving the brightness and color uniformity issue while maintaining the high efficiency of LED light sources.
Solution Approach 2:
The patent introduces light-modifying portions as intermediary elements between the LED light sources and the display panel. These intermediaries convert or adjust the light properties (color temperature) of peripheral regions, acting as a mediator to harmonize the optical characteristics across different areas of the backlight unit.
2Weight of moving object
If light-emitting devices are disposed on the rear side of the display device, then device weight is reduced, but image quality uniformity deteriorates due to light path differences
Solution Approach 1:
The patent maintains the lightweight advantage of rear-side LED placement while compensating for the resulting non-uniformity by implementing light-modifying portions with spatially varying properties. The peripheral light-modifying portions are specifically designed to adjust their optical characteristics to match the central area, achieving uniform image quality without sacrificing weight reduction.
3Productivity
If multiple light paths are created for emitted light, then optical efficiency is improved, but color consistency between different paths deteriorates
Solution Approach 1:
The patent introduces light-modifying portions as intermediary elements in the light paths, particularly for peripheral light that would otherwise have different color characteristics. These intermediaries adjust the color temperature of light from different paths to ensure consistency, allowing multiple light paths to coexist while maintaining uniform color output across the display.
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 improves image quality and optical efficiency by reducing brightness deviations and preventing color differences, resulting in more uniform luminance and reduced occurrence of mura (image defects) in the display devices.
Implementation Method 1
a phosphor film on the substrate; a plurality of light-emitting devices on the substrate between the substrate and the phosphor film, the plurality of light-emitting devices emitting light, a part of the emitted light traveling along a first path that passes through the phosphor film
Implementation Method 2
a light-modifying sheet with patterns that scatter, reflect, or diffract light to reduce brightness deviations and enhance image quality
Implementation Method 3
a light-modifying sheet with patterns that scatter, reflect, or diffract light to reduce brightness deviations and enhance image quality
Implementation Method 4
a light-modifying sheet with patterns that scatter, reflect, or diffract light to reduce brightness deviations and enhance image quality
Data Source
AI summary
In an embodiment, a display device comprises a display panel and a backlight unit. The backlight unit comprises a substrate, phosphor film, light-emitting devices, and light-modifying portion. A part of light emitted by the light-emitting devices traveling along a first path that passes through the phosphor film and another part of the emitted light traveling along a second path that bypasses the phosphor film. The light-modifying portion is in the second path and modifies a color of the other part of the emitted light so that the modified color is closer to a color of the part of the light through the phosphor film than a color of the emitted light at the light-emitting devices.