Color Filter Gap Structure for Low Color-Mix Imaging Sensors
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Solution Overview
Problem
Imaging devices face challenges in achieving both improved sensitivity and reduced color mixture, with existing technologies often compromising on one aspect at the expense of the other.
Innovation Solution
The imaging device incorporates a semiconductor substrate with pixels and photoelectric converters, featuring color filters with a gap section and a light-blocking section at the bottom, along with a protective film covering the color filters to minimize light absorption and discoloration, allowing for enhanced sensitivity and reduced color mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light-blocking section is provided to reduce color mixture, then color mixture is reduced, but sensitivity deteriorates due to increased light absorption
Solution Approach 1:
The gap section divides the space between adjacent color filters into separate regions, preventing light from reaching the light-blocking section while maintaining color filter isolation. This segmentation allows the light-blocking section to function for color mixture reduction without absorbing useful incident light, thereby resolving the contradiction between color mixture reduction and sensitivity maintenance
Solution Approach 2:
The gap section acts as an intermediary structure between adjacent color filters. It provides optical isolation that reduces color mixture at the interfaces between color filters and the light-blocking section, while its transparent nature allows incident light to pass through to the photoelectric converter, thus maintaining sensitivity
2Area of moving object
If color filters are provided closely together to improve pixel density, then pixel density is improved, but color mixture increases due to light scattering at interfaces
Solution Approach 1:
The gap section segments the optical path between adjacent color filters, creating distinct optical zones for each pixel. This segmentation prevents light scattered at the color filter interfaces from entering adjacent pixels, thereby reducing color mixture while allowing high pixel density through close spacing of color filters
Solution Approach 2:
The gap section provides localized optical isolation precisely where color mixture occurs at the interfaces between adjacent color filters. By targeting only the critical interface regions with gap sections, the invention maintains high pixel density overall while locally preventing color mixture at specific problem areas
3Measurement precision
If the light-blocking section is enlarged to reduce color mixture, then color mixture is reduced, but sensitivity deteriorates due to increased light absorption
Solution Approach 1:
The gap section extracts or removes the problematic interface region between color filters from the light path. By taking out this interface area and replacing it with a gap, the light-blocking section can be optimized for color mixture reduction without needing to be enlarged, as the gap itself provides the isolation function that would otherwise require a larger light-blocking section
Solution Approach 2:
The gap section serves as a transparent intermediary that replaces the need for an enlarged light-blocking section. It provides the necessary optical isolation to reduce color mixture while allowing light transmission, thereby eliminating the trade-off between color mixture reduction and light absorption that would occur with a larger light-blocking section
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
This configuration enhances sensitivity while minimizing color mixture by reflecting incident light at the interface between color filters and the gap section, reducing absorption in the light-blocking section and suppressing discoloration, thus achieving a better optical performance.
Implementation Method 1
the light incident from the subject without passing through the on-chip lens is reflected at the interface between the color filters and the gap section
Implementation Method 2
the plurality of photoelectric converters that generates, through photoelectric conversion, an electric charge corresponding to an amount of received light
Data Source
AI summary
An imaging device according to an embodiment of the present disclosure includes: a semiconductor substrate having a first surface and a second surface that are opposed to each other, and including a plurality of pixels and a plurality of photoelectric converters, the plurality of pixels disposed in a matrix, and the plurality of photoelectric converters that generates, through photoelectric conversion, an electric charge corresponding to an amount of received light incident from a subject without passing through an on-chip lens for each of the pixels; a plurality of color filters provided one for each of the plurality of pixels on side of the first surface; a first protective film that covers top surfaces and side surfaces of the plurality of color filters; a gap section provided between the plurality of respective color filters; and a light-blocking section provided at a bottom of the gap section.