Image Reader Chip Offset Correction via Storage Capacitor
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Solution Overview
Problem
Image reader devices with multiple image sensor chips face defects in image readouts due to variations in characteristics between chips, particularly at boundaries, leading to suboptimal image quality.
Innovation Solution
The implementation of an image reader device with a capacitor-based system that corrects for offset components across image reader chips, using a constant voltage output portion to store and correct electric charges, thereby minimizing variations and preventing defects at chip boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple image reader chips are used to increase the scanning area, then the coverage area is improved, but image quality deteriorates due to characteristic variations between chips causing defects at boundaries
Solution Approach 1:
The patent applies preliminary action by storing the offset component (characteristic variation) of each image reader chip in advance in a storage capacitor before actual image reading. This pre-stored offset information is then used during reading to correct the pixel signals, thereby compensating for chip-to-chip variations and preventing boundary defects in the final image.
2Area of stationary object
If multiple image reader chips are arranged in series to expand coverage, then the scanning coverage is improved, but image quality deteriorates due to offset components causing defects at chip boundaries
Solution Approach 1:
The patent implements feedback by measuring the actual offset component of each image reader chip and storing it in a storage capacitor. This stored offset information is then fed back during the reading process to correct pixel signals, creating a closed-loop system that continuously compensates for characteristic variations and maintains reliable image quality across multiple chips.
3Manufacturing precision
If a capacitor is added to store offset components for correction, then image quality is improved by suppressing variations, but device complexity increases
Solution Approach 1:
The patent applies local quality by adding the storage capacitor and offset correction circuitry only to the output circuit portion of each image reader chip, specifically where pixel signals are processed. This localized approach enables offset correction functionality without requiring complete redesign of the entire imaging system, thereby improving image quality 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 solution effectively suppresses variations between image reader chips, preventing defects in read images and improving overall image quality by correcting offset components across the device.
Implementation Method 1
a pixel portion that outputs a pixel signal, the pixel portion including a light receiving element that receives light from the image and performs photoelectric conversion
Implementation Method 2
a capacitor having a first terminal that is selectively connected to the transfer interconnect and a second terminal that is selectively connected to the output circuit; and a constant voltage output portion that outputs a constant voltage signal, and the constant voltage output portion is selectively connected to the first terminal of the capacitor via the output circuit
Data Source
AI summary
Each of a plurality of image reader chips included in an image reader device includes: a readout circuit that reads out a pixel signal output from a pixel portion; a transfer interconnect; an output circuit that outputs the pixel signal; a capacitor that is selectively connected between the transfer interconnect and the output circuit; and a constant voltage circuit. The constant voltage circuit is selectively connected to a first terminal of the capacitor via the output circuit.