Laminated Solid-State Imaging Device with Light Shielding Layer
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Solution Overview
Problem
Existing solid-state imaging devices face limitations in image resolution due to the number of photoelectric converters, particularly when both imaging and focus detection signals are generated on the same substrate, leading to deterioration in captured image quality.
Innovation Solution
A solid-state imaging device is designed with a laminated structure comprising a first substrate with photoelectric converters for focus detection and a second substrate with photoelectric converters for imaging, along with micro lenses and a light shielding layer that selectively allows light passage through specific pupil regions, enhancing focus detection accuracy and image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photoelectric converters for imaging and focus detection are formed in the same substrate, then focus detection function is achieved, but the number of photoelectric converters for imaging is limited and resolution deteriorates
Solution Approach 1:
The imaging device is divided into two separate substrates: a first substrate containing photoelectric converters for focus detection and a second substrate containing photoelectric converters for imaging. This segmentation allows each substrate to be optimized for its specific function, with the imaging substrate having a higher density of photoelectric converters for improved resolution while the focus detection substrate handles phase difference detection.
Solution Approach 2:
The invention transitions from a planar single-substrate design to a three-dimensional laminated structure with multiple substrates stacked in different layers. This dimensional change enables simultaneous focus detection and high-resolution imaging by distributing photoelectric converters across multiple vertical layers, effectively increasing the functional capacity without limiting the imaging converter count.
2Measurement precision
If photoelectric converters for focus detection and imaging are separated into different substrates, then image resolution is maintained, but device structure becomes more complex
Solution Approach 1:
Multiple functional components are merged into a unified laminated structure where the first substrate with focus detection photoelectric converters and the second substrate with imaging photoelectric converters are bonded together. This merging integrates focus detection and imaging functions into a single compact device while maintaining the ability to optimize each function independently through the layered architecture.
Solution Approach 2:
The laminated substrate structure serves multiple functions simultaneously: the first substrate performs focus detection through phase difference measurement, while the second substrate performs high-resolution imaging. This multi-functionality is achieved within a single integrated device package, avoiding the need for separate focus detection and imaging systems.
3Measurement precision
If light shielding layer with selection portion is added, then focus detection accuracy is improved, but device complexity increases
Solution Approach 1:
The light shielding layer is designed with a selection portion that extracts and blocks specific light paths. By selectively blocking light that would cause interference in focus detection while allowing useful light to pass through to the photoelectric converters, the structure improves focus detection accuracy by removing harmful optical paths without requiring complete light blocking.
Solution Approach 2:
The light shielding layer is not uniformly opaque but has spatially varying properties with transparent regions (selection portions) and opaque regions. This local quality variation allows light to pass through specific areas needed for imaging while blocking light in other areas that would interfere with focus detection, optimizing both functions with a single differentiated structure.
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 improves focus detection accuracy and maintains image resolution by optimizing the placement and functionality of photoelectric converters and micro lenses, allowing for better light management and increased sensitivity.
Implementation Method 1
a plurality of micro lenses which are disposed on an opposite face facing an imaging lens among faces of the second substrate and form an image of light passing through the imaging lens
Implementation Method 2
a first substrate which includes a plurality of first photoelectric converters arranged two-dimensionally; a second substrate which includes a plurality of second photoelectric converters arranged two-dimensionally
Data Source
AI summary
A solid-state imaging device includes: a first substrate having first photoelectric converters; a second substrate having second photoelectric converters and laminated on the first substrate; micro lenses disposed on an opposite face facing an imaging lens among faces of the second substrate and which forms an image of light passing through the imaging lens; and a light shielding layer disposed between the first and second photoelectric converters. The light shielding layer includes: a selection portion provided with an opening portion which selectively allows passage of only light passing through a partial region of a pupil region in an exit pupil of the imaging lens among light passing through the micro lens and transmitted through the second photoelectric converter; and a light shielding portion which shields an entire light passing through the micro lens and transmitted through the second photoelectric converter.