Scattering Envelope Upper Portion for Uniform LED Light Distribution
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Solution Overview
Problem
Conventional LED-based lighting devices have a directed light source that results in higher light intensity forwardly than laterally and backwardly, leading to a non-uniform light intensity distribution and a visible dark area at the top of the envelope, which does not resemble the omnidirectional light distribution of traditional incandescent bulbs.
Innovation Solution
A bulb-type lighting device with a bulb-shaped envelope featuring an upper portion with scattering properties that reflects and transmits light laterally and backwardly, increasing light intensity in these directions while maintaining forward light emission, thereby reducing the visible dark area and achieving a more uniform light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflector is arranged at the top of the envelope to reflect light laterally and backwardly, then light intensity in lateral and backward directions is increased, but a visible dark area appears at the top of the envelope due to blocked forward light
Solution Approach 1:
The envelope is designed with different optical properties in different regions: the upper portion has scattering properties to redirect light laterally and backwardly, while the lower portion maintains transparency for forward light emission. This local differentiation of optical qualities resolves the contradiction by providing directional light control without creating dark areas.
Solution Approach 2:
The patent changes the optical parameters of the envelope material by incorporating scattering properties in the upper portion. This parameter change allows the envelope to simultaneously transmit forward light and redirect lateral/backward light, eliminating the dark area problem while maintaining improved light distribution.
2Device complexity
If the light source is mounted at the base, then the device structure is simplified, but light intensity forwardly is higher than laterally and backwardly, creating non-uniform distribution
Solution Approach 1:
The envelope serves multiple functions simultaneously: it protects the light source, transmits forward light, and redirects lateral/backward light through its scattering upper portion. This multi-functionality achieves uniform light distribution without adding separate components, maintaining structural simplicity.
Solution Approach 2:
The upper portion of the envelope acts as an intermediary element that modifies the light path. It scatters and redirects light from the base-mounted source, creating uniform distribution without requiring complex mounting structures or additional reflectors.
3Illumination intensity
If a separate reflector is used to increase lateral and backward light intensity, then light distribution is improved, but the number of components and manufacturing complexity increases
Solution Approach 1:
The scattering functionality is merged directly into the envelope structure, eliminating the need for separate reflectors. The upper portion of the envelope itself provides the light redirection function, reducing component count and simplifying manufacturing while achieving uniform light distribution.
Solution Approach 2:
The envelope is designed to perform multiple functions: protection, forward light transmission, and lateral/backward light redirection through its scattering upper portion. This multi-functionality eliminates the need for separate reflectors, reducing device complexity while maintaining improved 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 solution enhances light intensity uniformly in lateral and backward directions, reducing the visible dark area and improving the lighting device's appearance to resemble an incandescent bulb, with the added benefit of fewer components required in manufacturing due to integrated scattering properties within the envelope.
Implementation Method 1
The envelope comprises an upper portion having scattering properties and being arranged to reflect a part of the light from the light source laterally and backwardly relative to the main forward emission direction
Implementation Method 2
the upper portion also transmits some of the light from the light source out of the envelope such that the upper portion (just like the remaining portion of the envelope) may appear to be luminous
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3e
AI summary
A lighting device (2) comprises a light source (210) having a main forward emission direction (20), and an envelope (220) in which the light source (210) is arranged. The envelope (220) comprises an upper portion (225) having scattering properties and being arranged to reflect a part of the light from the light source (210) laterally and backwardly relative to the main forward emission direction (20) and transmit a part of the light from the light source (210). The light intensity distribution of the lighting device (2) is more uniform, as backward and lateral light intensity is increased while the light in the main forward emission direction (20) is still admitted.