Direct-Lit LCD Backlight Lens Layout for Uniform Luminance
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Solution Overview
Problem
Direct-type LCD devices face issues with uneven luminance due to regions over LEDs being brightly irradiated while regions between LEDs are dimly irradiated, necessitating the use of more LEDs to improve luminance uniformity, which increases manufacturing costs.
Innovation Solution
A backlight module design that incorporates a substrate with four LED light sources at the corners of a rectangle-shaped lighting unit, each equipped with a lens to direct light rays uniformly across a rectangular area, achieving consistent luminance using fewer LEDs and potentially eliminating the need for a diffuser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If more LEDs are used to improve luminance uniformity, then luminance uniformity is improved, but manufacturing cost increases
Solution Approach 1:
A lens is introduced as an intermediary component between the LED and the display panel. The lens modifies the light distribution pattern, directing more light toward regions between LEDs and controlling the intensity at different locations. This mediator enables uniform luminance distribution using fewer LEDs, resolving the contradiction between luminance uniformity and LED quantity.
Solution Approach 2:
The lens creates non-uniform light intensity distribution that compensates for the inherent non-uniformity of LED illumination. By designing the lens with specific optical properties, the system achieves uniform overall luminance through localized intensity variation, allowing fewer LEDs to cover the entire display area effectively.
2Illumination intensity
If more LEDs are used to improve luminance uniformity, then luminance uniformity is improved, but device thickness increases
Solution Approach 1:
The lens serves as a compact intermediary that achieves uniform luminance distribution without requiring additional LEDs or increased device thickness. The lens's optical design enables efficient light redistribution within a thin profile, maintaining device thinness while improving luminance uniformity.
3Illumination intensity
If a diffuser is added to improve luminance uniformity, then luminance uniformity is improved, but device complexity increases
Solution Approach 1:
The lens replaces the diffuser as the intermediary component for achieving luminance uniformity. The lens provides more precise control over light distribution through optical design, eliminating the need for diffusers and reducing overall device complexity while maintaining uniform luminance output.
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 provides improved luminance uniformity and reduces manufacturing costs by optimizing the placement and lens configuration of LEDs, allowing for thinner display devices without the need for additional LEDs or diffusers.
Implementation Method 1
The first lens directing light rays emitted from the first LED onto (1) a first corner of the rectangular area on the interface of the display device
Data Source
AI summary
A display device includes a display panel, a first light source, and second light source. The first and second light sources are respectively aligned with a first spot and second spot in a direction perpendicular to a substrate. The first light source irradiates the first and second spots with luminance of a first value and second value, respectively. The first light source irradiates a midpoint between the first and second spots with a luminance value that is half the addition of the first and second values.