Image Sensor Pixel Lens Positioning for Light Condensing
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Solution Overview
Problem
Existing image sensors face challenges in increasing light condensing ratios while preventing unnecessary light incidence, which complicates the manufacturing process due to the need for multiple planarization films with light-shielding walls.
Innovation Solution
An image sensor design featuring a pixel array with a first and second inner-layer lens and an on-chip microlens, where the positional differences between the lens centers and the photoelectric conversion unit satisfy specific relationships, allowing for a light-shielding wall between adjacent pixels to inhibit unnecessary light incidence without the complexity of multiple planarization films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple planarization films with light-shielding walls are provided between on-chip microlens and light-receiving surface, then light condensing ratio is improved and crosstalk is inhibited, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the light-shielding function into the planarization film structure itself by forming light-shielding walls that extend from the pixel region into the planarization film. This integration eliminates the need for separate light-shielding structures while maintaining both light condensing and crosstalk prevention functions, thereby reducing manufacturing process complexity
Solution Approach 2:
The light-shielding walls extend vertically into the planarization film layer, utilizing the vertical dimension to block oblique light paths between adjacent pixels. This three-dimensional approach to light shielding provides effective crosstalk prevention while maintaining a simple planarization film structure that can be manufactured with standard semiconductor processes
2Object-affected harmful factors
If light-shielding walls are provided between adjacent pixels, then crosstalk is prevented, but device structure becomes more complex
Solution Approach 1:
The light-shielding function is merged with the planarization film by forming light-shielding walls that are integral parts of the planarization film structure. These walls extend vertically from the pixel region into the planarization film, providing crosstalk prevention without requiring separate light-shielding layers or complex multi-layer structures
Solution Approach 2:
The planarization film structure itself provides the light-shielding function through its vertically extending walls. The same structural element that planarizes the surface also serves as the light-shielding barrier, making the structure self-sufficient and eliminating the need for additional dedicated light-shielding components
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 effectively increases light condensing ratios while simplifying the manufacturing process by reducing the need for complex light-shielding structures, thereby enhancing light management and image capture efficiency.
Implementation Method 1
the pixels each include a first inner-layer lens, a second inner-layer lens whose distance from the photoelectric conversion unit is larger than a distance from the photoelectric conversion unit to the first inner-layer lens
Implementation Method 2
an on-chip microlens whose distance from the photoelectric conversion unit is larger than the distance from the photoelectric conversion unit to the second inner-layer lens
Implementation Method 3
a light-shielding wall around the second inner-layer lens is provided between adjacent pixels
Implementation Method 4
pixels each including a photoelectric conversion unit
Data Source
AI summary
An image sensor comprising pixels each includes, an photoelectric conversion unit, a first inner-layer lens, a second inner-layer lens, and an on-chip microlens. A light-shielding wall around the second inner-layer lens is provided between adjacent pixels. A first positional difference between center positions of the first inner-layer lens and the photoelectric conversion unit, a second positional difference between center positions of the second inner-layer lens and the photoelectric conversion unit, and a third positional difference between center positions of the on-chip microlens and the photoelectric conversion unit satisfy: the second positional difference<the first positional difference<the third positional difference.