Solid-State Imaging Device Smear Aliasing Prevention
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Solution Overview
Problem
Conventional solid-state imaging devices experience image quality defects due to smear aliasing when reducing pixels for moving picture imaging, particularly when using empty transfer stages, which leads to vertical line artifacts and deterioration in image quality.
Innovation Solution
The device incorporates a plurality of light-receiving elements arranged in rows and columns with vertical transfer units that mix signal packets and dummy packets within the same column, preventing mixing with packets from different columns, and includes hold units with independent transfer electrodes to manage charge transfer effectively, thereby preventing smear aliasing and image quality defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixels are reduced in vertical direction by continuously transferring signal charges from multiple vertical transfer stages to the horizontal transfer unit, then frame frequency increases, but smear aliasing occurs and image quality deteriorates
Solution Approach 1:
The patent divides the transfer process into separate stages: vertical transfer units transfer charges to intermediate holding regions, which then transfer to the horizontal transfer unit. This segmentation prevents direct mixing of charges from multiple vertical stages, eliminating smear aliasing while maintaining high frame frequency capability.
Solution Approach 2:
The patent introduces intermediate holding regions (first holding regions and second holding regions) as mediators between vertical transfer units and the horizontal transfer unit. These intermediaries buffer and isolate charge packets, preventing harmful mixing while enabling continuous transfer for high frame frequency operation.
2Quantity of substance
If pixels are reduced in horizontal direction by selecting every other pixel, then the number of pixels decreases, but horizontal resolution is reduced
Solution Approach 1:
The patent compensates for horizontal pixel reduction by utilizing vertical transfer stages to their full capacity. By reducing pixels horizontally but maintaining full vertical transfer capability with multiple stages and intermediate holding regions, the overall imaging performance is preserved through dimensional balance.
3Quantity of substance
If empty transfer stages are used for vertical pixel reduction, then pixel thinning is achieved, but vertical line artifacts appear due to charge mixing from different columns
Solution Approach 1:
The patent extracts and removes the problematic mixing function from the transfer process. By separating vertical transfer and horizontal transfer into distinct stages with intermediate holding regions, the harmful charge mixing that causes vertical line artifacts is eliminated while pixel thinning functionality is preserved.
Solution Approach 2:
Intermediate holding regions act as mediators that prevent direct interaction between charges from different vertical columns. This isolation eliminates the charge mixing that causes vertical line artifacts while still enabling pixel reduction through selective transfer.
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 solution effectively prevents smear aliasing and enhances image quality by ensuring that signal charges are not mixed with dummy packets from different columns, maintaining image integrity during pixel reduction for moving picture imaging.
Implementation Method 1
a plurality of light-receiving elements which are arranged by rows and columns; and a plurality of vertical transfer units each of which is arranged for a corresponding column of the light-receiving elements
Data Source
AI summary
A solid-state imaging device includes: a plurality of light-receiving elements which are arranged by rows and columns. A driving unit performs a driving, so that a signal packet and a plurality of dummy packets in an identical column are mixed together into a mixed packet in each holding units, charges of the mixed packet are held in a hold unit, the held charges of the mixed packet are vertically transferred to a horizontal transfer unit so that the mixed packet is mixed with a mixed packet of a different hold unit which is vertically transferred from the different hold unit to the horizontal transfer unit.