Light Emitting Device Using Wavelength Conversion for Green Laser Display
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Solution Overview
Problem
Current light emitting devices for laser displays and projectors face challenges with low brightness, large size, and high power consumption, particularly in achieving sufficient luminous flux and emitting green light using laser diodes, as no laser diode has been developed to emit green light directly.
Innovation Solution
A light emitting device comprising a light source, a light guide with a higher refractive index core and cladding, a wavelength conversion member that absorbs and converts excitation light, and a shielding member to block unwanted wavelengths, allowing for high brightness, reduced size, and increased luminous flux, including the emission of green light using a laser diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a laser diode is used as a light source to reduce device size and power consumption, then device size and power consumption are reduced, but green light emission is not achieved since no green laser diode has been developed
Solution Approach 1:
The patent changes the wavelength parameter of the light source from green (which doesn't exist in laser diodes) to blue/violet (405-480nm), and uses a wavelength conversion member to transform this light into green light, thereby achieving green light emission through parameter transformation rather than direct generation
Solution Approach 2:
The patent introduces a wavelength conversion member as an intermediary between the blue/violet laser diode and the desired green light output. This intermediary component converts the wavelength from blue/violet to green, enabling green light emission without requiring a green laser diode
2Device complexity
If conventional light sources like LEDs are used, then device structure is simpler, but brightness and luminous flux are insufficient
Solution Approach 1:
The patent replaces conventional LED light sources with laser diodes, substituting a different light generation mechanism that provides higher brightness and luminous flux. The laser diode's coherent light generation mechanism delivers superior illumination intensity compared to incoherent LED emission
3Object-generated harmful factors
If SHG laser or gas laser is used to achieve green light emission, then green light can be emitted, but device size increases and power consumption increases due to complicated structure
Solution Approach 1:
The patent changes the approach from using complex SHG or gas lasers to using a simple blue/violet laser diode combined with a wavelength conversion member. This parameter change in the light source selection achieves green light emission while maintaining a compact and low-power device structure
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 enables a compact, energy-efficient light emitting device that can produce green light and increase luminous flux, addressing the limitations of existing technologies by utilizing a laser diode as a light source and optimizing light guidance and conversion.
Implementation Method 1
a light guide that propagates the excitation light, and in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding)
Implementation Method 2
a wavelength conversion member that absorbs the excitation light propagated by the light guide and converts the wavelength thereof, and releases light of a predetermined wavelength band
Data Source
AI summary
A light emitting device, comprises: a light source that emits excitation light; a light guide that propagates the excitation light, and in which the refractive index of the center part (core) of a cross section is higher than the refractive index of the peripheral part (cladding); a wavelength conversion member that absorbs the excitation light propagated by the light guide and converts the wavelength thereof, and releases light of a predetermined wavelength band; and a shielding member that blocks the wavelength of at least part of the excitation light and the light emitted from the wavelength conversion member.