Multilayer Wavelength Conversion Element for Projectors
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Solution Overview
Problem
Existing wavelength conversion elements in projector lighting devices face issues with deterioration of the reflection layer, leading to decreased fluorescence extraction efficiency due to ion or oxygen diffusion and stress from bonding materials, resulting in reduced reflectance and adhesion problems with protective films.
Innovation Solution
A wavelength conversion element is designed with a multilayer structure including a reflection layer, a protective layer with a first metal and inorganic oxide, and a stress-relieving second metal layer, which captures ion or oxygen diffusion and relieves bonding pressure, ensuring adhesion and preventing deterioration, thereby maintaining reflectance and extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal protective film is provided on the Ag reflection layer, then the adhesion between the protective film and reflection layer is improved, but ions or oxygen diffuse from the bonding material and deteriorate the reflection layer
Solution Approach 1:
The protective film is segmented into multiple layers: a first protective film layer (metal) for adhesion, a second protective film layer (inorganic oxide) for barrier protection against ion and oxygen diffusion, and a third protective film layer (metal) for stress relief. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between adhesion and deterioration prevention.
Solution Approach 2:
The inorganic oxide layer acts as an intermediary barrier between the bonding material and the Ag reflection layer. It intercepts and blocks the diffusion path of ions and oxygen from the bonding material, preventing them from reaching and deteriorating the reflection layer while allowing the metal layers to maintain adhesion.
2Reliability
If an inorganic oxide protective film is provided on the Ag reflection layer, then ion or oxygen diffusion is blocked, but the adhesion between the reflection layer and protective film becomes weak and peeling occurs
Solution Approach 1:
The protective film is divided into multiple layers with the inorganic oxide layer positioned between metal layers. The metal layers provide strong adhesion to both the Ag reflection layer and the inorganic oxide layer, while the inorganic oxide layer provides the barrier function. This segmentation resolves the adhesion weakness of single-layer inorganic oxide films.
Solution Approach 2:
The protective film uses a composite structure combining metal and inorganic oxide materials. The metal layers provide mechanical strength and adhesion, while the inorganic oxide layer provides chemical barrier properties. This composite approach leverages the complementary strengths of different materials to simultaneously achieve adhesion and protection.
3Stability of the object's composition
If a bonding material is used to bond the phosphor layer to the substrate, then the structural integrity is improved, but stress from the bonding material destroys the protective film and deteriorates the reflection layer
Solution Approach 1:
The protective film is segmented into multiple layers with the inorganic oxide layer serving as a stress-resistant barrier. This layered structure allows the protective film to withstand the stress from the bonding material without destruction, while still maintaining structural integrity of the entire wavelength conversion element.
Solution Approach 2:
The multilayer protective film structure is designed beforehand to cushion and absorb the stress generated by the bonding material. The inorganic oxide layer and metal layers work together to distribute and mitigate stress, preventing film destruction before it can occur during the bonding process.
4Ease of manufacture
If the reflection layer is deteriorated, then the manufacturing process is simplified, but the reflectance decreases and fluorescence extraction efficiency is reduced
Solution Approach 1:
The protective film is segmented into multiple layers, each designed to prevent specific deterioration mechanisms. This comprehensive protection system ensures the reflection layer maintains its high reflectance and the wavelength conversion element maintains high fluorescence extraction efficiency throughout its service life.
Solution Approach 2:
The inorganic oxide layer, which might add manufacturing complexity, actually benefits the system by providing a barrier that prevents deterioration. The additional layer converts the potential harm of bonding material stress and diffusion into a protective mechanism that enhances long-term performance and maintains productivity.
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 multilayer structure effectively suppresses the deterioration of the reflection layer, maintaining high reflectance and fluorescence extraction efficiency, reducing light loss, and enhancing the reliability of the wavelength conversion element.
Implementation Method 1
a second layer which is provided facing the first layer, contains either silver or aluminum, and reflects the excitation light or a light obtained by wavelength conversion of the excitation light by the wavelength conversion layer
Implementation Method 2
a wavelength conversion layer which has a first face on which an excitation light is incident and a second face facing the first face
Data Source
AI summary
A wavelength conversion element includes a wavelength conversion layer which has a first face on which an excitation light is incident and a second face facing the first face, a first layer which is provided facing the second face and contains a first inorganic oxide, a second layer which is provided facing the first layer, contains either silver or aluminum, and reflects the excitation light or a light obtained by wavelength conversion of the excitation light by the wavelength conversion layer, a third layer which is provided facing the second layer and contains a first metal other than silver or aluminum, a fourth layer which is provided facing the third layer and contains the first inorganic oxide or a second inorganic oxide that is different from the first inorganic oxide, and a fifth layer which is provided facing the fourth layer and contains a metal.