Dual-Lens Prism System for Uniform LED Illumination
Solution Overview
Problem
In display devices using light-emitting diode elements, uneven luminance occurs due to the radial spreading of mixed light, leading to dark regions between bright areas, especially when the distance between light-emitting elements is large, resulting in inefficient light utilization and increased costs and power consumption.
Innovation Solution
A light source device configuration featuring a first lens with diffusing prisms on its light-entering surface and a second lens with prisms on its light-exiting surface, arranged between the light guide plate and the light-emitting element portion, to effectively mix and direct light towards the light guide plate, ensuring uniform luminance and reducing the number of light-emitting elements needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light-emitting elements are closely arranged to prevent dark regions, then uniform luminance is improved, but light-emitting element efficiency deteriorates due to excessive light generation
Solution Approach 1:
A lens portion with specific optical structures (first lens with first prisms and second lens with second prisms) is introduced as an intermediary between the light-emitting elements and light guide plate. This intermediary redirects light that would otherwise contribute to dark regions back toward the light guide plate, achieving uniform luminance without requiring closer spacing of light-emitting elements, thus maintaining their efficiency
Solution Approach 2:
The patent changes the optical parameters by introducing prisms with specific refractive indices and angles on the lenses. These parameter changes enable precise control of light redirection, allowing light to be efficiently guided from light-emitting elements through the lens system to the light guide plate, achieving uniform illumination without increasing element density
2Device complexity
If the distance between light-emitting elements is increased, then device complexity is reduced, but luminance uniformity deteriorates due to dark regions appearing between bright regions
Solution Approach 1:
The lens portion acts as a mediating optical system that bridges the gap between widely spaced light-emitting elements. The first and second lenses with their respective prisms redirect light paths to ensure uniform coverage across the light guide plate, enabling larger spacing between elements while maintaining luminance uniformity
Solution Approach 2:
The patent introduces a new dimensional aspect by adding the lens portion as a separate optical layer between the light-emitting elements and light guide plate. This additional dimension provides new degrees of freedom for light path control, allowing elements to be spaced further apart while achieving uniform illumination through the lens-mediated light redistribution
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 enhances light utilization efficiency by minimizing uneven luminance and reducing the number of light-emitting diodes required, thereby lowering costs and power consumption while maintaining effective light distribution.
Implementation Method 1
a plurality of first diffusing prisms arranged on the first light-entering surface and capable of diffusing light emitted from the second lens and introducing the light into the first lens
Implementation Method 2
a plurality of first prisms arranged on the first light-exiting surface; and a second lens arranged between the first lens and the light-emitting element portion, and having a second light-exiting surface arranged at a position facing the first light-entering surface, a second light-entering surface on a side opposite to the second light-exiting surface, and a plurality of second prisms arranged on the second light-exiting surface
Data Source
AI summary
A lens portion of a display device includes: a first lens arranged between a light guide plate and a light-emitting element portion, and having a plurality of first prisms arranged on a first light-exiting surface; and a second lens arranged between the first lens and the light-emitting element portion, and having a plurality of second prisms arranged on a second light-exiting surface arranged at a position facing a light-entering surface. The first lens includes a plurality of diffusing prisms arranged on the light-entering surface and capable of diffusing light emitted from the second lens and introducing said light into the first lens.