Plasmon Filtered Red Pixels for Red-Dot Ghost Suppression
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Solution Overview
Problem
Conventional solid-state imaging elements fail to reliably eliminate the red-dot ghost phenomenon when capturing high-luminance subjects, leading to suboptimal image quality due to residual reflection issues.
Innovation Solution
Incorporating a plasmon filter with a predetermined periodic pattern in the filter layer of red pixels, which includes a plasmon resonator, to selectively transmit wavelengths and reduce oblique incidence effects, thereby eliminating the red-dot ghost phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a diffraction grating is provided to reduce reflection, then occurrence of red-dot ghost phenomenon is reduced, but it cannot reliably eliminate the phenomenon
Solution Approach 1:
The patent changes the optical parameters of the filter layer by introducing a plasmon filter with specific periodic pattern and plasmon resonance characteristics. This filter is designed to transmit only specific wavelength bands (e.g., 500-550nm and 600-650nm) while blocking other wavelengths, thereby reliably eliminating the red-dot ghost phenomenon that conventional diffraction gratings cannot fully prevent.
Solution Approach 2:
The patent employs a composite filter structure combining a conventional color filter layer with a plasmon filter layer. The plasmon filter layer contains metal nanoparticles or periodic structures that exhibit plasmon resonance, creating a composite system that achieves both color filtering and plasmon-based wavelength selection to reliably eliminate ghost phenomena.
2Measurement precision
If conventional filters are used in the filter layer, then basic color separation is achieved, but oblique incidence effects cause wavelength shifts and reduce imaging accuracy
Solution Approach 1:
The plasmon filter is designed with specific structural parameters (periodic pattern pitch, metal nanoparticle size and spacing) that make the transmitted wavelength bands insensitive to incidence angle. The plasmon resonance condition maintains stable wavelength transmission even for oblique incidence, preventing the wavelength shifts that occur with conventional filters.
3Illumination intensity
If the filter layer transmits all wavelengths, then maximum light intensity is achieved, but red-dot ghost phenomenon occurs due to reflection and re-reflection
Solution Approach 1:
The plasmon filter is selectively applied only to red pixel regions where the red-dot ghost phenomenon occurs, rather than filtering all pixels uniformly. This localized filtering approach maintains high light transmission for green and blue pixels while eliminating ghost phenomena in red pixels, preserving overall image brightness.
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 effectively eliminates the red-dot ghost phenomenon, improving image quality by ensuring that only desired wavelengths are transmitted through the plasmon filter, even at oblique incidence angles, resulting in better image capture performance.
Implementation Method 1
a plasmon filter disposed in the filter layer of at least some red pixels of a plurality of the red pixels that receives light in a red wavelength region, the plasmon filter including a plasmon resonator having a predetermined periodic pattern
Data Source
AI summary
The present disclosure relates to a solid-state imaging element and electronic apparatus that achieve image capturing with better image quality. A solid-state imaging element includes a semiconductor substrate in which a photoelectric conversion element is provided for each pixel, a filter layer stacked on a light-receiving surface side of the semiconductor substrate, and a plasmon filter disposed in the filter layer of at least some red pixels of a plurality of the red pixels that receives light in a red wavelength region, the plasmon filter including a plasmon resonator having a predetermined periodic pattern. Then, in the plasmon filter, a pitch of the pattern is corrected according to a position at which the red pixel is disposed. The present technology can be applied to, for example, an imaging element package.