Imaging Element Trench Light Shielding for Phase Detection
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Solution Overview
Problem
Existing imaging devices face challenges in improving phase difference detection accuracy while preventing color mixture between adjacent pixels, which occurs due to obliquely entering light.
Innovation Solution
Incorporating a trench between imaging pixels with a first light shielding film embedded in the trench and a second light shielding film continuous with the first film on the light receiving surface of adjacent pixels, allowing obliquely entering light to be shielded and condensed at appropriate positions for accurate phase difference detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If curvatures of on-chip lenses are varied or light receiving surfaces are at different levels, then phase difference detection accuracy is improved, but color mixture occurs due to obliquely entering light through adjacent pixels
Solution Approach 1:
The patent divides the light shielding function into multiple segments: a first light shielding film embedded in trenches between pixels, and a second light shielding film provided on the light receiving surface. This segmented approach allows each film to perform its function optimally while working together to prevent color mixture between adjacent pixels
Solution Approach 2:
The patent introduces light shielding films as intermediary structures between adjacent pixels. These films act as mediators that block obliquely entering light from reaching adjacent pixels, thereby preventing color mixture while allowing the optical system to maintain its phase difference detection capabilities
2Object-generated harmful factors
If a light shielding film is provided between adjacent pixels, then color mixture is reduced, but phase difference detection accuracy may deteriorate due to light blocking
Solution Approach 1:
The patent applies light shielding films with specific local characteristics: the first light shielding film is embedded in trenches at specific locations between pixels, and the second light shielding film is provided on the light receiving surface. This localized application ensures light shielding occurs only where necessary to prevent color mixture, while preserving light reception areas needed for phase difference detection
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 phase difference detection speed and accuracy while minimizing color mixture between adjacent pixels, maintaining high pixel characteristics and automatic focusing performance.
Implementation Method 1
In the light receiving section, entering light is photoelectrically converted to generate signal charges
Implementation Method 2
the light condensing section is configured to allow entering light to be condensed toward the light receiving section
Data Source
AI summary
An imaging element according to the present disclosure includes: a first pixel and a second pixel each including a light receiving section and a light condensing section, in which the light receiving section includes a photoelectric conversion element, and the light condensing section is configured to allow entering light to be condensed toward the light receiving section; a trench provided between the first pixel and the second pixel; a first light shielding film embedded in the trench; and a second light shielding film provided on part of a light receiving surface of the light receiving section of the second pixel, in which the second light shielding film is continuous with the first light shielding film.