Backlight Unit Wavelength-Selective Reflective Films
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Solution Overview
Problem
Current backlight units for display devices face challenges in achieving improved image quality and narrow bezel designs, with issues such as luminance non-uniformity and the occurrence of 'mura' (smear defects) due to uneven light distribution and bluish-colored bands at the bezel boundaries.
Innovation Solution
The implementation of a backlight unit design featuring a light emitting unit emitting light in a first wavelength band, a phosphor film excited to emit light in multiple wavelength bands, and strategically positioned reflective films to manage light reflection and transmission, along with a dam to enhance light efficiency and uniformity, allowing for a narrow bezel and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional backlight unit structure is used, then the manufacturing process is simple, but luminance non-uniformity and mura defects occur
Solution Approach 1:
The reflective film is divided into multiple wavelength-selective reflective films (first, second, and third reflective films) that reflect different wavelength bands. This segmentation allows precise control of light distribution across different spectral regions, eliminating luminance non-uniformity and mura defects while maintaining a manageable structural complexity through modular wavelength-specific reflection layers.
2Area of stationary object
If the bezel width is reduced, then the display area is increased, but bluish-colored bands appear at the bezel boundaries
Solution Approach 1:
Different wavelength-selective reflective films are positioned at specific locations within the backlight unit to address local optical issues. The first reflective film reflects blue light (first wavelength band) to control bezel boundary coloration, while the second and third reflective films manage other wavelength bands. This localized wavelength-specific reflection eliminates bluish bands at bezel boundaries while maximizing the display area.
3Manufacturing precision
If the light distribution is optimized, then the image quality is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention optimizes light distribution by changing the reflection parameters of different wavelength bands through multiple wavelength-selective reflective films. Each reflective film is designed with specific optical parameters (reflection wavelengths, positions, and characteristics) to control light propagation. This parameter-based approach improves image quality through precise spectral control while maintaining manufacturing feasibility by using standard optical film technologies.
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 solution effectively suppresses luminance non-uniformity and 'mura' by optimizing light distribution, enabling a clear distinction between the bezel and display areas while allowing for a narrow bezel design and enhanced image quality.
Implementation Method 1
a phosphor film excited by the light in the first wavelength band emitted from the light emitting unit to emit the light in the first to a third wavelength bands
Implementation Method 2
a first reflective film disposed in a position corresponding to a rim of the phosphor film and causing to reflect the light in the first wavelength band
Implementation Method 3
a second reflective film disposed in a position corresponding to an inner side of the phosphor film than the first reflective film and causing to reflect the light in the second and third wavelength bands
Data Source
AI summary
Embodiments of the present disclosure provide a backlight unit comprising at least one light emitting unit emitting light in a first wavelength band, a phosphor film exciting the light in the first wavelength band emitted from the light emitting unit to emit the light in the first to a third wavelength bands, a first reflective film disposed in a position corresponding to a rim of the phosphor film and causing to reflect the light in the first wavelength band, a second reflective film disposed adjacent to the first reflective film and causing to reflect the light in the second and third wavelength bands, and a dam disposed around the light emitting unit. A display device using the backlight unit is also provided.