Recessed Reflector Light Emitting Device
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Solution Overview
Problem
Existing light emitting devices with reflectors suffer from reduced light utilization efficiency due to light being introduced into interstices between the reflector and the surface on which it is mounted, caused by thermal stress, uneven surfaces, or warping, leading to inefficient light reflection.
Innovation Solution
A light emitting device design where the reflector's lower portion is placed within a recess on the board, with a side wall interposed between the reflector and the light emitting element, or the reflector is adhered to the board with a resin capable of reflecting light, preventing light from entering interstices and enhancing reflection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a reflector is mounted directly on a base surface, then the device structure is simple, but light is introduced into interstices reducing light utilization efficiency
Solution Approach 1:
The reflector is nested within a recess formed in the base, creating a stepped configuration where the reflector bottom sits below the base surface. This nesting structure eliminates interstices between the reflector and base while maintaining effective light reflection, as the reflective surface remains positioned to intercept and redirect light from the light emitting element.
Solution Approach 2:
The solution transitions from a two-dimensional surface mounting approach to a three-dimensional stepped configuration by forming a recess in the base. This dimensional change allows the reflector to be positioned at a lower level, eliminating gaps and interstices that would otherwise allow light to escape, thereby improving light utilization efficiency without significantly complicating the manufacturing process.
2Reliability
If an interstice is formed between the base and reflector to avoid cracks from thermal stress, then thermal stress resistance is improved, but light is introduced into the interstice reducing light utilization efficiency
Solution Approach 1:
The reflector is nested within a recess in the base, creating a stepped configuration that eliminates interstices. This nesting approach maintains thermal stress resistance by allowing for material expansion and contraction without creating gaps, while simultaneously preventing light from entering interstices, thus resolving the contradiction between thermal reliability and light utilization efficiency.
Solution Approach 2:
The recess structure acts as an intermediary between the base and reflector, providing a transition zone that accommodates thermal stress differences while preventing light leakage. The recessed configuration allows the reflector to be securely positioned without direct surface contact that would create interstices, thereby maintaining both thermal stress resistance and light reflection efficiency.
3Loss of energy
If the inner peripheral surface of the reflector is made highly smooth (arithmetical average roughness reduced to 0.01 μm or less), then light reflection efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies different surface quality requirements to different regions of the reflector. The inner peripheral surface that directly reflects light is maintained with high smoothness (arithmetical average roughness of 0.01 μm or less) to ensure efficient light reflection, while other surfaces such as the bottom and outer surfaces can have less stringent finish requirements, thereby reducing overall manufacturing complexity while maintaining light reflection efficiency.
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 design effectively prevents light from entering interstices, improving light utilization efficiency by ensuring that emitted light is either reflected by the resin or the recess's side wall, thereby increasing the amount of light radiated outward.
Implementation Method 1
a light emitting element disposed within a space surrounded by a reflective surface of a reflector disposed on a board
Implementation Method 2
the bottom of the reflector is adhered on the surface of the board with a resin which is capable of reflecting light emitted by the light emitting element
Data Source
AI summary
A light emitting device comprises a light emitting element disposed within a space surrounded by a reflective surface of a reflector disposed on a board. A lower portion of the reflector is placed within a recess formed in the board, and a side wall of the recess is interposed between the lower end of the reflective surface of the reflector and the light emitting element.