Advantages
- Simple fabrication with conventional semiconductor processes for mass production
- It can be applied to a motion sensor and a filter for medical imaging in one-chip element
- Simultaneous color and polarization images can be acquired, which is impossible with organic pigment color filters
Background & Technology
Conventionally, filter elements utilizing surface plasmon resonance have been developed, and there is a need for filters that exhibit selectivity of transmission wavelengths for light in a specific wavelength range. There is also a need for bandpass filters with multiple transmission bands, especially covering a spectral band between visible light region and the near-infrared (NIR) light region.
In this research, we have developed a filter that can respond to such demands. It consists of an aluminum film with a grating shape and periodic concavo-convex structure and a film thickness (10 nm to 50 nm) where the surface plasmons of both interfaces interfere with each other. Compared to conventional technology, this filter has a narrower transmission wavelength band (100nm→50nm), higher light transmittance (30%→60%), and multi-band capability (8-band→16-band), and covers not only visible light but also multi-spectrum in the near infrared region. We have confirmed by simulation that the optical properties are not limited to visible light.
Therefore, visible/NIR filtered images, visible and polarized light images are obtained with a single chip. These imaging techniques can be realized with a reasonable manufacturing process to meet the needs of biological NIR imaging comparisons in the same field of color imaging, automotive and security applications in dark environment, and the telecommunications field.
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Data
Transmitted light image of plasmonic polarizing color filter
The optimized spectral thin film exhibited multiband transmitted light colors corresponding to the period 200-500 nm.
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Researcher
National University Corporation Shizuoka University Graduate School of Integrated Science Electronics and Materials Science Course Professor Atsushi ONO
Patent
JP7560888 Filter elements and image pickup devices including filter elements
Publication
ITE Technical Report Vol.46,No.41 IST2022-45(Dec.2022)
Development Phase
Current stage:
Manufacturing method for this color filter element has been established and performance evaluation has been completed.
Next stage:
1) Optimization of wavelength selectivity/transmittance for each application
2) Development of this filter element for imaging devices and imaging equipment
If any company is interested in the practical application or commercialization of this color filter element, or is interested in performance evaluation or joint research for the intended use, we would be happy to start with a discussion.
Project No.ON-05134