Hexagonal Pixel Radiation Detector Layout

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Solution Overview

Problem

In direct-conversion-type radiographic image detecting apparatuses, the narrow interline pitch of signal lines hinders miniaturization and increases resistance, making it difficult to maintain common voltage and leading to reduced sensitivity and resolution due to the need for auxiliary capacitors and specific wiring configurations.

Innovation Solution

The use of hexagonal-shaped pixels with beveled corners and data lines that bend along the peripheral edges, along with straight common ground lines that do not intersect with data lines, allows for efficient layout and reduced resistance, enabling greater miniaturization without narrowing the interline pitch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If common ground lines are made to snake to match data lines in hexagonal pixel arrays, then data lines do not intersect with common ground lines, but the interline pitch becomes narrower and resistance increases

Engineering Contradiction:
Improvecommon voltage stabilityVSAvoidinterline pitch
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent applies asymmetry by positioning TFT switches at different locations in alternating pixel rows. In even-numbered rows, switches are positioned on one side while in odd-numbered rows, switches are positioned on the opposite side. This asymmetric arrangement allows common ground lines to extend straight without snaking, maintaining wide interline pitch while preventing intersections with data lines, thus resolving the contradiction between voltage stability and line spacing.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces dynamic positioning of TFT switches that varies by row parity. Rather than a fixed symmetric position for all pixels, the switch position dynamically alternates between left and right sides depending on the row number. This dynamic arrangement enables straight common ground line routing while maintaining proper electrical connections, solving the interline pitch narrowing problem.

Inventive Principle:
Principle #15Dynamics

2Reliability

If common ground lines are made narrower to fit within pixel boundaries, then intersections with data lines are avoided, but line resistance increases making it difficult to maintain common voltage

Engineering Contradiction:
Improvecommon voltageVSAvoidline width
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

By using asymmetric TFT switch positioning in alternating rows, the patent creates sufficient horizontal space for common ground lines to maintain adequate width without intersecting data lines. The asymmetric layout distributes switching elements to opposite sides of pixels in alternating rows, effectively widening the available path for common ground lines and reducing their resistance while maintaining voltage stability.

Inventive Principle:
Principle #4Asymmetry

3Area of stationary object

If data lines and common ground lines are positioned closer together, then pixel size can be reduced, but capacitance between lines increases hindering miniaturization

Engineering Contradiction:
Improvepixel sizeVSAvoidline capacitance
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The asymmetric TFT positioning strategy creates optimized spacing between data lines and common ground lines. By placing switches on opposite sides in alternating rows, the layout maximizes the distance between signal-carrying data lines and reference-potential common ground lines, minimizing parasitic capacitance while still achieving compact pixel dimensions suitable for miniaturization.

Inventive Principle:
Principle #4Asymmetry

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 allows for increased miniaturization of radiographic image detecting elements while maintaining signal quality and resolution, reducing noise and capacitance between signal lines, and stabilizing the common voltage.

Implementation Method 1

a semiconductor film that receives irradiated radiation and generates charges

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP3062348B1Radiation detection element and radiograph detection device
Publication Date: 2017.07.12 FUJIFILM CORP
  • EP3062348B1 patent drawingFigure 1
  • EP3062348B1 patent drawingFigure 2
  • EP3062348B1 patent drawingFigure 3

AI summary

The present invention provides a radiation detecting element (10) that avoids the interline pitch of signal lines (3) becoming narrower. Namely, the shape of pixels (20) configuring the radiation detecting element is made hexagonal, and each of the pixels is arrayed in a honeycomb pattern. The position of the TFT switches (4) in each of the pixels is disposed to the right side or the left side of the center of the pixels so as to be left-right direction different for each of the pixel rows (20a-d), and common ground lines (30) that fix storage capacitor lower electrodes (14) of charge storage capacitors (5) are configured laid out in substantially straight lines lower than pixel electrodes (11).