Organic EL Light Emitting Apparatus End-Face Extraction
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Solution Overview
Problem
Conventional semiconductor lasers are expensive, large in size, and have limited applications due to fixed wavelengths, making it difficult to produce a cost-effective, compact light emitting apparatus that can emit linear or laser beams with arbitrary wavelengths and facilitate easy modulation.
Innovation Solution
A light emitting apparatus with an EL emitting unit consisting of a light emitting layer sandwiched by light blocking layers, which radiates EL light efficiently from its end, and an optical guiding member that adjusts excitation density to achieve high light utilization efficiency and modulate the light into a laser beam with a different wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an inorganic semiconductor laser is used to emit a linear beam, then the laser beam can be obtained with a sharp spectrum width and high directionality, but the apparatus becomes expensive and large in size
Solution Approach 1:
The patent changes the material parameter from inorganic semiconductor to organic EL element, which allows achieving laser emission with different material properties that reduce apparatus size and cost while maintaining beam quality
Solution Approach 2:
The patent employs organic EL elements which are cheaper and easier to manufacture than inorganic semiconductor lasers, replacing expensive materials with more economical alternatives that still achieve the desired laser performance
2Ease of manufacture
If an inorganic semiconductor laser is used, then high carrier mobility allows use of relatively thick layers, but the potential drop and Ohmic loss conditions become difficult to satisfy
Solution Approach 1:
The patent changes the material system from inorganic semiconductor to organic EL, fundamentally altering electrical properties and allowing different layer thickness regimes that satisfy both manufacturing ease and electrical performance requirements
3Device complexity
If a flat optical waveguide is used to extract EL light from the organic EL element, then the structure is simple, but only 20% of EL light is radiated to the waveguide resulting in low utilization efficiency
Solution Approach 1:
The patent transitions from extracting light in the lateral direction (2D plane) to extracting light from the end face (1D linear extraction), fundamentally changing the geometric dimension of light extraction to achieve near-100% utilization efficiency
Solution Approach 2:
The patent creates an asymmetric light extraction configuration where light is extracted preferentially from the end face rather than laterally, using asymmetric positioning of the optical waveguide relative to the EL element to achieve directional light extraction
4Ease of manufacture
If the wavelength of laser beam is specified by semiconductor material types, then manufacturing is simplified, but arbitrary wavelength emission cannot be obtained limiting applications
Solution Approach 1:
The patent employs organic EL elements that can emit across a broad wavelength range, making the light source universal and adaptable to multiple applications by simply changing the organic material, rather than requiring different semiconductor material systems for each wavelength
5Illumination intensity
If excitation density in the organic EL light emitting layer is increased to achieve laser oscillation, then the light emitting layer thickness must be increased, but this increases the potential drop and reduces modulation efficiency
Solution Approach 1:
The patent extracts light from the end face (1D linear extraction) rather than laterally (2D plane extraction), concentrating the light extraction path and achieving high excitation density in a compact structure without increasing layer thickness
Solution Approach 2:
The patent creates a dynamic light extraction system where the optical waveguide is positioned to optimize light coupling from the EL element end face, allowing efficient light extraction with minimal layer thickness and maintained modulation 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
The apparatus achieves high light utilization efficiency, enabling the emission of 100% of EL light as a linear or laser beam with adjustable wavelength, overcoming the size and cost limitations of conventional semiconductor lasers and facilitating easy modulation.
Implementation Method 1
an electroluminescent (EL) emission as a light source
Implementation Method 2
an optical guiding member which optically guides the EL light
Implementation Method 3
A light emitting material existing in the core layer 31 is excited by the EL light to emit a coherent light
Data Source
AI summary
A light emitting apparatus of the present invention includes: an EL emitting unit including at least a light emitting layer which generates an EL light; and a pair of light blocking layers arranged such that they sandwich the light emitting layer so that the layers block the EL light generated in the light emitting layer and that the EL light is radiated only from the end of the light emitting layer; and a light emitting unit which optically guides the EL light radiated from the end of the light emitting layer and emits a light having a wavelength equal to or different from that of the EL light. The EL light is emitted only from the end of the light emitting layer since the EL light generated in the light emitting layer is blocked by the pair of light blocking layers. This emitted EL light is optically guided by the light emitting unit and emitted as it is or a light having a different wavelength from the EL light.