Micro Lens Dead-Zone Layout for Color-Accurate Image Sensors
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Solution Overview
Problem
Image sensors with micro lenses face issues of light angle dependency and channel difference problems, leading to shadows and light entering adjacent pixels instead of the corresponding pixel, due to varying focal points for different wavelengths of light.
Innovation Solution
The image sensor design includes multiple sub-pixel groups with overlapping micro lenses of varying dead zones, ensuring that light from micro lenses enters the corresponding pixel regardless of the incident light type, with all micro lenses having the same height and differing dead zone sizes to accommodate different color filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a micro lens is used to collect light to the anode area, then pixel sensitivity is increased, but shadows occur when the incident light angle is outside the CRA
Solution Approach 1:
The patent applies local quality by creating dead zones with different sizes around micro lenses corresponding to different color filters. Each dead zone is locally optimized to handle the specific optical characteristics of its associated color channel, allowing light collection to be tailored to each wavelength's behavior rather than using a uniform approach for all colors.
Solution Approach 2:
The patent changes the parameter of dead zone size to compensate for optical aberrations. By varying the dead zone dimensions based on the color filter type (red, green, blue), the system adjusts the effective light collection area to maintain consistent focus across different wavelengths, thereby reducing shadows and channel differences.
2Productivity
If a micro lens is used to collect light, then light collection efficiency is improved, but channel difference problems occur due to different focal points for different wavelengths
Solution Approach 1:
The patent implements local quality by assigning different dead zone sizes to micro lenses based on their color filter type. This local differentiation allows each color channel to have optimized light collection parameters, ensuring that red, green, and blue lights all converge at the same focal point despite their different wavelengths, thereby eliminating channel differences while maintaining high light collection efficiency.
Solution Approach 2:
The patent uses parameter changes by adjusting the dead zone size parameter according to the color filter characteristics. This parameter adjustment compensates for the different focal lengths of various wavelengths, allowing the system to maintain both high productivity in light collection and precise focus consistency across all color channels.
3Manufacturing precision
If the dead zone size is varied for different color filters, then focus consistency is achieved, but device complexity increases
Solution Approach 1:
The patent applies local quality by varying dead zone sizes only in the regions where color filters are positioned, while maintaining a simple overall lens structure. This localized differentiation achieves focus consistency for different wavelengths without requiring complex global structural changes, thus balancing manufacturing precision with device simplicity.
Solution Approach 2:
The patent introduces asymmetry by creating non-uniform dead zone sizes around different color filters. This asymmetric design is strategically applied only where needed (around specific color filter positions) rather than throughout the entire device, achieving focus consistency while minimizing the increase in overall device complexity.
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 design improves image quality by ensuring light enters the correct pixel, reducing channel differences and shadows, and simplifies the design by maintaining a consistent focal point for all incident light types.
Implementation Method 1
a first micro lens at least partially overlapping the plurality of first unit pixels, a second micro lens at least partially overlapping the plurality of second unit pixels, a third micro lens overlapping the plurality of third unit pixels
Implementation Method 2
a first color filter, a second color filter, and a third color filter
Data Source
AI summary
An image sensor includes a first sub-pixel group including a plurality of first unit pixels, a first color filter, a first micro lens at least partially overlapping the plurality of first unit pixels, a second sub-pixel group including a plurality of second unit pixels, a second color filter, a second micro lens at least partially overlapping the plurality of second unit pixels, a third sub-pixel group including a plurality of third unit pixels, a third color filter, a third micro lens at least partially overlapping the plurality of third unit pixels, a first dead zone in which the first micro lens does not overlap the first sub-pixel group, a second dead zone in which the second micro lens does not overlap the second sub-pixel group, and a third dead zone in which the third micro lens does not overlap the third sub-pixel group.