Illuminating Lens Radial Light Distribution via Total Reflection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional illuminating lenses for light emitting diodes (LEDs) in liquid-crystal display backlights have limitations in widening the range of light transmission directions, leading to restricted illuminance distribution and increased costs due to the need for a large number of LEDs to achieve uniform brightness.
Innovation Solution
An illuminating lens design that utilizes total reflection to distribute light radially, featuring a light exit surface with a transmissive region and a total reflection region, along with a second convex exit surface to further spread light, allowing for a wider range of transmission directions and stabilizing illuminance with a reflective layer on the bottom surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lens with concave and convex surfaces is used to widen the range of transmission directions, then the illuminance distribution becomes wider, but the difference in height between concave and convex surfaces must be reduced, limiting further widening of transmission directions
Solution Approach 1:
The light exit surface is divided into two distinct regions: a transmissive region for light transmission and a total reflection region for light reflection. This segmentation allows each region to be optimized independently, enabling wider transmission directions without being constrained by height differences between concave and convex surfaces.
Solution Approach 2:
Instead of relying solely on refraction through concave and convex surfaces, the invention inverts the approach by utilizing total internal reflection at the light exit surface. This alternative mechanism achieves wider light distribution without the geometric constraints of traditional refractive lens designs.
2Illumination intensity
If the number of light emitting diodes is increased to achieve uniform brightness, then the uniformity of illuminance improves, but the cost and device complexity increase
Solution Approach 1:
The invention extracts and utilizes total internal reflection, an optical phenomenon occurring at the interface between media, to achieve uniform light distribution. This eliminates the need to deploy multiple LEDs across the surface, reducing device complexity while maintaining brightness uniformity.
Solution Approach 2:
The light exit surface acts as an intermediary element that redirects light from the light source through total internal reflection. This intermediary mechanism distributes light uniformly across the target surface without requiring multiple light sources, simplifying the overall device structure.
3Illumination intensity
If refraction is used to distribute light, then the light can be spread, but the difference in height between surfaces must be minimized, limiting the widening of transmission directions
Solution Approach 1:
The invention replaces the mechanical/refractive approach (using concave and convex surface height differences to bend light) with an optical approach (using total internal reflection to redirect light). This substitution eliminates the constraint of surface height differences while achieving effective light distribution.
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 design effectively widens the range of light transmission directions, reduces the number of LEDs required, and stabilizes illuminance on the surface to be irradiated, while maintaining a low-cost configuration.
Implementation Method 1
the total reflection region totally reflects light that has been emitted from the starting point at a relatively large angle with respect to the optical axis and then reached the first light exit surface
Implementation Method 2
the transmissive region transmits light that has been emitted from the starting point at a relatively small angle with respect to the optical axis and then reached the first light exit surface
Data Source
AI summary
A light exit surface of an illuminating lens has a first light exit surface and a second light exit surface. The first light exit surface is recessed toward a point on the optical axis, and the second light exit surface extends outwardly from the periphery of the first light exit surface. The first light exit surface has a transmissive region and a total reflection region. When the position of a light source on the optical axis is defined as a starting point, the transmissive region transmits light that has been emitted from the starting point at a relatively small angle with respect to the optical axis, and the total reflection region totally reflects light that has been emitted from the starting point at a relatively large angle with respect to the optical axis. A reflective layer is formed on a bottom surface that surrounds a light entrance surface and faces oppositely to the light exit surface. The reflective layer reflects light that has been emitted from the light source, totally reflected repeatedly at the light exit surface, and then reached the bottom surface.