Cockcroft-Walton Board Stacking for Compact X-Ray High Voltage Generation

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Solution Overview

Problem

High voltage generators, particularly those employing Cockcroft-Walton circuits in medical X-ray applications, face challenges in downsizing due to the need for large, high-voltage capacitors and the increased size resulting from arranging capacitors in series, which impedes compact design and productivity.

Innovation Solution

The design incorporates three or more circuit boards with flat capacitors and diodes connected to the boards, where middle boards have indentations for diode placement, straight lead wires, and capacitors mounted on both sides of the boards in parallel, along with a jig for precise positioning, facilitating a compact and reliable structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If capacitors are arranged in series to achieve high voltage, then the voltage applied per stage is sufficient, but the circuit size increases in the horizontal direction

Engineering Contradiction:

Improvewithstand voltage capabilityVSAvoidcircuit board arrangement area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent transitions from horizontal series arrangement to vertical stacking of circuit boards. Multiple circuit boards are arranged in the thickness direction (vertical dimension) rather than spreading out horizontally. This dimensional change allows the same number of capacitors to be compacted into a smaller horizontal footprint while maintaining the series voltage multiplication capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If capacitors are made large-sized with high withstand voltage, then the voltage requirements are met, but the circuit size increases and downsizing is impeded

Engineering Contradiction:

Improvevoltage withstand capabilityVSAvoidcapacitor volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent divides the high voltage generation function across multiple circuit boards, each containing smaller capacitors with lower individual withstand voltage ratings. Instead of using one or two large capacitors, the system segments the voltage multiplication into stages across multiple boards, where each board handles a portion of the total voltage requirement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent arranges multiple circuit boards in the thickness direction (vertical stacking), allowing smaller capacitors to be positioned at different heights. This vertical arrangement compensates for the smaller capacitor size by increasing the number of capacitors in series through the third dimension, thereby achieving the required total voltage without increasing horizontal footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If end electrodes of capacitors are made large, then connection reliability is improved, but excessive downsizing is refused

Engineering Contradiction:

Improveconnection reliabilityVSAvoidelectrode area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent moves the connection interface from a two-dimensional plane to a three-dimensional vertical arrangement. Multiple circuit boards with smaller electrodes are stacked in the thickness direction, allowing sufficient connection area to be achieved through vertical stacking rather than increasing the horizontal area of individual electrodes.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Volume of moving object

If bent lead wires are used in diodes, then space utilization is improved, but manufacturing complexity and productivity are reduced

Engineering Contradiction:

Improvespace utilizationVSAvoidassembly productivity

Core Design Contradiction:

Volume of moving objectVSProductivity

Solution Approach 1:

The patent incorporates lead wire bending into the diode manufacturing process itself, so that the lead wires are pre-formed to the required shape before assembly. This preliminary action eliminates the need for manual bending during assembly, thereby maintaining space efficiency while improving productivity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual mechanical bending operations with automated lead wire forming processes during diode manufacturing. This substitution of mechanical assembly operations with automated manufacturing processes improves productivity while maintaining the space-efficient bent lead wire configuration.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11778718B2High voltage generator and X-ray generator

Publication Date: 2023.10.03 MEIDENSHA CORP

AI summary

A high voltage generator including a Cockcroft-Walton circuit structured to receive alternating-current power supplied from an alternating-current power source and apply a potential difference to a load includes: three or more circuit boards arranged at intervals in a thickness direction thereof; capacitors, each of which is shaped flat and mounted to a corresponding one of the circuit boards; and diodes, each of which is connected to corresponding ones of the circuit boards. Out of the three or more circuit boards, each circuit board other than two circuit boards disposed at both ends of the arrangement of the three or more circuit boards includes indentations. Each of the diodes is disposed in a corresponding one of the indentations.