Light Emitting Device With Inverted Laser Path And Shielded Cap
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Solution Overview
Problem
Conventional light emitting devices have poor light extraction efficiency due to laser beams entering the lateral face of the phosphor member, leading to absorption or scattering of light, and safety concerns arise when using optical members to redirect the laser beam.
Innovation Solution
A light emitting device design featuring a laser element, a phosphor member, a first optical member that changes the laser beam's direction to obliquely irradiate the phosphor member, and a cap with a light shielding member and a light transmissive member to enhance light extraction and safety by preventing stray light from escaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a laser beam enters a lateral face of the phosphor member, then the device structure is simple, but light extraction efficiency is poor due to absorption or scattering inside the phosphor member
Solution Approach 1:
Instead of entering the phosphor member from the lateral face as in conventional designs, the laser beam is inverted to enter from the upper face and exit through the lower face, allowing light to be extracted from the upper face with minimal internal absorption or scattering
Solution Approach 2:
A first optical member (prism) is introduced as an intermediary between the laser element and the phosphor member to change the traveling direction of the laser beam, enabling it to enter the upper face of the phosphor member at an appropriate angle
2Loss of energy
If an optical member is disposed to change the laser beam's traveling direction towards the upper face of the phosphor member, then light extraction efficiency is improved, but stray light may travel directly towards the window creating safety concerns
Solution Approach 1:
The harmful stray light is extracted and separated from the useful light path by positioning the laser beam entry and exit faces of the optical member at different locations, allowing independent control and shielding of the exit side
Solution Approach 2:
The potential harmful stray light exiting the optical member is converted into a controllable element by using a light shielding member with a through hole that directs only the necessary light while blocking stray light, turning a safety hazard into a controlled light path
3Object-affected harmful factors
If the light shielding member blocks all stray light, then safety is improved, but useful light may be blocked reducing luminance
Solution Approach 1:
The light shielding member is designed with a through hole that provides localized light transmission only in the necessary direction, while blocking light in other directions, achieving both safety and luminance requirements through spatially selective light control
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 improves light extraction efficiency, increases luminance, allows for miniaturization, and enhances safety by effectively redirecting the laser beam and reducing heat generation within the phosphor member.
Implementation Method 1
a first optical member disposed on the upper face of the base, including an entry-side lateral face through which the laser beam enters and an exit-side lateral face through which the laser beam exits, and changing the laser beam's traveling direction
Implementation Method 2
a phosphor member disposed on the upper face of the base and emits fluorescent light when irradiated with the laser beam
Data Source
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AI summary
A light emitting device (100) includes: a base (10); a laser element (20) disposed on an upper face of the base and adapted to laterally emit a laser beam; a phosphor member (40) disposed on the upper face of the base; a first optical member (30) disposed on the upper face of the base and configured to change a traveling direction of the laser beam such that the laser beam transmitted through the first optical member irradiates an upper face of the phosphor member; and a cap (50). The cap comprises: a light shielding member (51) and a light transmissive member (57) located over the through hole, the laser element, the phosphor member, and the first optical member, wherein the light shielding member includes a protruded portion (53) extending downward to a position that is lower than an upper end of the first optical member (30) so as to face the exit-side lateral face (30b) of the first optical member.