Solid-State Imaging Column Amplifier Gain Selection

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Solution Overview

Problem

Existing solid-state imaging apparatuses face challenges in achieving an improved signal-to-noise (S/N) ratio and increased dynamic range due to complex circuit configurations and increased costs associated with multiple gain signals, leading to signal saturation and unequal pixel S/N ratios.

Innovation Solution

A solid-state imaging apparatus with column amplifier units generating signals at different gains and an analog-to-digital converting unit that selectively converts signals to digital form, allowing for gain error detection and correction using a correction coefficient, thereby improving S/N ratio and dynamic range while reducing noise and circuit complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple detection circuits with different gains are provided for each column to improve S/N ratio and dynamic range, then signal quality improves, but circuit complexity and area increase

Engineering Contradiction:

ImproveS/N ratioVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple detection circuits with different gains are merged into a single detection circuit. The circuit selectively amplifies pixel signals with different gains and outputs both amplified signals to a single ADC, thereby improving S/N ratio and dynamic range while reducing circuit complexity and area.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single detection circuit is designed to perform multiple functions: it can amplify pixel signals with different gains (first gain and second gain) and output both amplified signals. This multi-functional design eliminates the need for separate detection circuits for each gain level.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple detection circuits with different gains are provided for each column to increase dynamic range, then dynamic range improves, but circuit area increases

Engineering Contradiction:

Improvedynamic rangeVSAvoidcircuit area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If both low-gain and high-gain signals are subjected to AD conversion to maintain S/N ratio and increase dynamic range, then signal quality improves, but the number of data transfer lines increases

Engineering Contradiction:

ImproveS/N ratioVSAvoidnumber of data transfer lines

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The ADC is configured to selectively ADC pixel signals with different gains. Instead of providing separate ADCs for each gain level, a single ADC is used to convert both first amplified signals and second amplified signals, thereby reducing the number of data transfer lines while maintaining S/N ratio and dynamic range.

Inventive Principle:

Principle #5Merging (Combining)

4Quantity of substance

If data transfer for different gain signals is performed alternately and successively to reduce data transfer lines, then data transfer lines are reduced, but transfer time doubles and photographic speed decreases

Engineering Contradiction:

Improvenumber of data transfer linesVSAvoidphotographic speed

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The ADC is configured to simultaneously or continuously ADC pixel signals with different gains rather than alternately and successively. This continuous operation maintains high photographic speed while reducing the number of data transfer lines, as both first amplified signals and second amplified signals can be processed without doubling the transfer time.

Inventive Principle:

Principle #20Continuity of useful action

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 effectively enhances the S/N ratio and dynamic range of the imaging apparatus by correcting gain errors, reducing noise, and simplifying the circuit configuration, resulting in improved image quality and reduced costs.

Implementation Method 1

a photodiode PD that performs photoelectric conversion and generates a signal

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS9191600B2Solid-state imaging apparatus that selects among different analog signals

Publication Date: 2015.11.17 CANON KK

AI summary

A solid-state imaging apparatus is provided which includes a plurality of pixels (101) arranged in a matrix for generating a signal by a photoelectric conversion, a plurality of column amplifier units (102) arranged each correspondingly to each of columns of the plurality of pixels, for outputting a first signal generated by amplifying at a first gain the signals from the plurality of pixels, and a second signal generated by amplifying at a second gain the signals from the plurality of pixels, and an analog to digital converting unit (108) for selecting one signal from the first and second signals for analog to digital conversion.