LED Illuminating Lens Radial Light Distribution
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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, restricting the reduction of LED numbers and increasing costs due to the need for uniform brightness across large areas.
Innovation Solution
An illuminating lens design featuring a light entrance and exit surface with a transmissive region and total reflection region, where light is refracted and reflected to spread the light radially, allowing for a wider range of transmission directions by utilizing total reflection and refraction, and a ring portion to guide light away from the optical axis for enhanced illuminance distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of light emitting diodes is reduced to lower cost, then cost is reduced, but the area to be irradiated by each LED must be increased which requires widening the range of transmission directions
Solution Approach 1:
The light exit surface is divided into multiple regions with different functions: a first light exit surface with a transmissive region and a total reflection region, and a second light exit surface. This segmentation allows different portions of light to be handled differently - some transmitted directly and some reflected - thereby widening the overall range of transmission directions without requiring additional LEDs
Solution Approach 2:
Light that is initially reflected back toward the light source undergoes periodic interaction with the optical system, being reflected again by total reflection at the first light exit surface and then guided toward the surface to be irradiated. This periodic action of reflection and redirection expands the transmission direction range
2Ease of manufacture
If conventional lens designs are used with refraction only, then manufacturing is simpler, but the range of transmission directions cannot be widened beyond a certain limit
Solution Approach 1:
The invention changes the optical parameters by introducing total reflection in addition to refraction. The light exit surface is designed with specific geometric parameters (concave first light exit surface, convex second light exit surface) that enable total reflection, fundamentally altering how light is directed without complicating manufacturing
Solution Approach 2:
Light that would normally be lost by reflecting back toward the light source is converted into a beneficial resource. The total reflection region captures this otherwise wasted light and redirects it toward the target surface, widening the transmission direction range while maintaining manufacturing simplicity
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 achieves a wider range of light transmission directions and a more uniform illuminance distribution on the surface, reducing the number of LEDs required and minimizing the impact of structural members behind the lens on illuminance, thus enhancing the efficiency and cost-effectiveness of the lighting system.
Implementation Method 1
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
Implementation Method 2
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 3
The second light exit surface has a shape capable of transmitting approximately the entire amount of light that has been emitted from the starting point and then reached the second light exit surface
Data Source
AI summary
An illuminating lens includes a main body and a ring portion. The main body has a light exit surface, and the light exit surface has a first light exit surface recessed toward a point on the optical axis and a second light exit surface extending outwardly from the periphery of the first light exit surface. The first light exit surface has a transmissive region in the center thereof, and a total reflection region on the peripheral side thereof. The ring portion has a back surface configured to guide the light that has been emitted from a light source, totally reflected repeatedly at the light exit surface, and then entered the ring portion to an end surface by total reflection.