Amorphous Silicon Photosensor Pixel Structure Eliminates Switching Transistor

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Solution Overview

Problem

The complexity of pixel structures in existing photosensor arrays requires a signal read switching transistor, increasing costs and complicating the design.

Innovation Solution

A photosensor array configuration that eliminates the need for a signal read switching transistor by using a lower electrode, an amorphous silicon film, an n-type amorphous silicon film, and an upper electrode, with a switch circuit and detector circuit that outputs voltage changes after a given period, allowing for simplified pixel structure without the need for a signal read switching transistor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a signal read switching transistor is used in the photosensor array, then the light detection capability is maintained, but the pixel structure complexity and manufacturing cost increase

Engineering Contradiction:

Improvelight detection capabilityVSAvoidpixel structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the signal read switching transistor from the photosensor pixel structure. By using the amorphous silicon film's inherent light-dependent variable resistance特性, the patent eliminates the need for the switching transistor while maintaining light detection capability, thus simplifying the pixel structure and reducing manufacturing cost

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The amorphous silicon film serves multiple functions: it acts as both the light-sensitive element and the variable resistance element that replaces the switching transistor functionality. This multi-functionality reduces the number of separate components needed in the pixel structure

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a signal read switching transistor is used in the photosensor array, then the light detection capability is maintained, but the manufacturing cost increases

Engineering Contradiction:

Improvelight detection capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the light-sensitive function and the switching function into a single amorphous silicon film component. This consolidation reduces the total number of components that need to be fabricated and assembled, thereby lowering manufacturing cost

Inventive Principle:

Principle #5Merging (Combining)

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 configuration simplifies the pixel structure and reduces costs by eliminating the need for a signal read switching transistor, while maintaining effective light detection capabilities.

Implementation Method 1

The amorphous silicon (a-Si) film of the photosensor in the invention disclosed in the filed Japanese Patent Application operates as the light-dependent variable resistance element in which a resistance is varied in response to an incident light

Methodology Applied

Scientific EffectPhotoconductivity: Photoconductivity

Data Source

PatentUS8963064B2Photosensor having upper and lower electrodes with amorphous silicon film and n-type amorphous silicon film therebetween and photosensor array

Publication Date: 2015.02.24 MAGNOLIA PURPLE CORP

AI summary

A photosensor array includes plural photosensor pixels. Each of the photosensor pixels includes a lower electrode, an amorphous silicon film, an n-type amorphous silicon film, and an upper electrode. The photosensor array includes plural scanning lines connected to the upper electrodes, plural read lines connected to the lower electrodes, a scanning circuit that is connected to the plural scanning lines, and sequentially supplies a selection scanning signal of a first voltage to the respective scanning lines, a first unit that inputs a second voltage higher than the first voltage to the plural read lines in a blanking period of one horizontal scanning period, and thereafter puts the plural read lines into the floating state, and a second unit that outputs a voltage change in each of the read lines within one horizontal scanning period as the sensor output voltage of the photosensor pixel.