Partial Row Readout Image Sensor Multiplexer Timesharing

Solution Overview

Problem

Medical image sensors face challenges in maintaining high image quality due to the degradation of signal transitions when transmitting data over long, thin cables with low bandwidth, which are poor conductors of high-frequency signals, leading to a degraded final image.

Innovation Solution

Implementing a partial row readout mechanism using multiplexer circuitry to timeshare sense amplifiers across multiple rows and columns, and outputting image data in sequential color groups to reduce abrupt voltage transitions, thereby improving signal quality over low-bandwidth communication channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If image data is transmitted over long, thin cables with high resistance and capacitance, then the cable flexibility and miniaturization are improved, but the signal quality degrades due to poor high-frequency conduction

Engineering Contradiction:

Improvecable sizeVSAvoidsignal quality

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-processing the image data at the sensor before transmission. Specifically, it performs row-based parallel readout and on-chip processing to prepare the data in a format that minimizes the impact of cable limitations, thereby proactively addressing the signal quality issue before transmission occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the temporal parameters of data transmission by implementing sequential row readout instead of simultaneous transmission. This parameter change spreads the transmission over time, reducing the bandwidth requirements and allowing effective transmission over thin cables with limited high-frequency conduction capabilities

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the photosensitive apertures are made as large as possible for a given chip size, then the image quality is improved, but the peripheral circuitry area increases

Engineering Contradiction:

Improveimage qualityVSAvoidperipheral circuitry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the pixel array into multiple rows that can be read out sequentially. This segmentation allows the use of shared peripheral circuitry (such as sense amplifiers and column readout circuits) across multiple rows, reducing the total peripheral circuitry area while maintaining large photosensitive aperture areas for high image quality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements multi-functionality by designing peripheral circuitry that serves multiple rows of pixels. The sense amplifiers and column readout circuits are shared resources that handle data from multiple rows sequentially, thereby reducing the overall amount of peripheral circuitry needed while supporting large photosensitive areas

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If sequential color group readout is implemented to reduce abrupt voltage transitions, then the signal quality over low-bandwidth channels is improved, but the readout time increases

Engineering Contradiction:

Improvesignal qualityVSAvoidreadout time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies segmentation by dividing the pixel array into multiple rows that can be read out sequentially. This segmentation allows the use of shared peripheral circuitry (such as sense amplifiers and column readout circuits) across multiple rows, reducing the total peripheral circuitry area while maintaining large photosensitive aperture areas for high image quality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements multi-functionality by designing peripheral circuitry that serves multiple rows of pixels. The sense amplifiers and column readout circuits are shared resources that handle data from multiple rows sequentially, thereby reducing the overall amount of peripheral circuitry needed while supporting large photosensitive areas

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8081247B2Partial row readout for image sensor

Publication Date: 2011.12.20 OMNIVISION TECHNOLOGIES INC

AI summary

An image sensor includes a color filter array, sense amplifiers, multiplexing circuitry, and an output. The color filter array acquires image data using an array of M columns and N rows of pixels. The sense amplifiers are coupled to the color filter array for reading out image data from the color filter array. The multiplexing circuitry couples the sense amplifiers to the color filter array, wherein each sense amplifier is time shared across multiple columns and multiple rows. The output is coupled to receive the image data from the sense amplifiers and output the image data off-chip.