Lens Light Control Emission Face Prevents Ray Crossover
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Solution Overview
Problem
Conventional illumination devices with point-like light sources and lenses often suffer from reduced illuminance uniformity due to crossover of emission rays, resulting in non-uniform illumination patterns, particularly in applications like photography and reading aids.
Innovation Solution
The use of a lens with a light control emission face that prevents crossover by directing light rays radially without inner reflection, ensuring higher flux density in directions deviated from the optical axis to maintain uniform illuminance across the illuminated region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional lens is used with a point-like light source, then light can be emitted through the lens, but emission rays cross each other within the illuminated region causing reduced illuminance uniformity
Solution Approach 1:
The patent applies local quality by creating a light control emission face with spatially varying properties. Different regions of the emission face have different light control capabilities - the central region controls rays to prevent crossover, while the outer edge region allows broader emission. This localized differentiation of light control properties throughout the illumination process achieves uniform illuminance without requiring complete structural redesign.
2Illumination intensity
If light rays are directed to improve uniformity, then illuminance uniformity improves, but light flux density in the optical axis direction becomes too low
Solution Approach 1:
The patent employs parameter changes by systematically varying the light control characteristics across the emission face. The light control emission face is designed with position-dependent parameters - rays from the central region are controlled to prevent crossover and ensure uniformity, while rays from the outer edge region maintain higher flux density. This gradual parameter transition optimizes both uniformity and energy utilization.
3Illumination intensity
If a light control emission face is introduced to prevent ray crossover, then illuminance uniformity improves, but device complexity increases
Solution Approach 1:
The patent merges the light control function directly into the lens emission face itself, eliminating the need for separate control elements. The light control emission face is integrated as the output surface of the lens, combining light emission and light control functions in a single structural element. This integration achieves uniform illuminance while minimizing additional device complexity.
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 illuminance uniformity by preventing ring-like brightening and ensuring consistent light distribution, improving the efficiency and uniformity of illumination across the illuminated area.
Implementation Method 1
a light control emission face that emits rays which reach the light control emission face after being emitted from the point-like light source and entering into the lens through the incidence face and travelling only within the lens without undergoing inner-reflection at any surface of the lens
Data Source
AI summary
Provided are an illumination device and a lens employed in the device for controlling light travelling direction, the device being capable of illuminating brightly and uniformly a certain limited region (region-to-be-illuminated) corresponding to an object such as subject for photography. The illumination device emits light H coming from a light emitting element (point-like light source) employing a LED as a light emitting source via the lens. A light control emission face of the lens emits light (rays), which is included in light H introduced into the lens through an incidence face thereof and travelling within the lens to the light control emission face without undergoing inner-reflection at any surface of the light control emission face, as illumination light. The light control emission face is configured so that no set of rays included in the illumination light make any crossover at least before reaching a region-to-be-illuminated and rays within a direction range near to a direction of optical axis L have lower light flux density as compared with that in the outside of the direction range.