Pyroelectric Crystal X-Ray Source Using Field Emission
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Solution Overview
Problem
Conventional x-ray sources are bulky, heavy, and require large external power supplies, limiting their portability and efficiency in medical and industrial applications, while existing miniaturization efforts face challenges in maintaining high voltage without breakdown and achieving controlled x-ray production.
Innovation Solution
A compact, self-contained x-ray source using a pyroelectric or piezoelectric crystal with micrometer-scale field emitters and a modular array configuration, where the crystal's temperature or mechanical strain is controlled to generate electrons that impinge on a bremsstrahlung target, producing x-rays without the need for a large power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional x-ray tubes are used, then x-ray production is reliable, but the device becomes bulky and heavy due to large power supplies and cooling systems
Solution Approach 1:
The invention divides the x-ray source into modular field emitter units that can be arranged in arrays. Each unit contains a small pyroelectric or piezoelectric crystal with micrometer-scale emitters, eliminating the need for a single large conventional x-ray tube and its associated bulky power supply and cooling infrastructure.
Solution Approach 2:
The field emitters use the pyroelectric or piezoelectric effect to generate high voltage internally through temperature or strain changes, eliminating the need for external high voltage power supplies. This self-powered mechanism dramatically reduces device weight while maintaining reliable x-ray production.
2Volume of moving object
If miniaturization is attempted with conventional tubes, then device size is reduced, but high voltage breakdown occurs and controlled x-ray production becomes difficult
Solution Approach 1:
The invention replaces the conventional electrical high voltage generation system with a mechanical/thermal system. Pyroelectric crystals generate high voltage through temperature changes, and piezoelectric crystals generate high voltage through mechanical strain, eliminating the need for complex electrical insulation and high voltage power supplies in miniaturized devices.
Solution Approach 2:
The invention changes the operating parameters from electrical high voltage input to thermal or mechanical input. By cycling the temperature or applying mechanical strain to the pyroelectric/piezoelectric crystal, the system generates the necessary high voltage internally, enabling stable operation in compact geometries without electrical breakdown.
3Use of energy by moving object
If conventional x-ray tubes are used, then x-ray intensity is sufficient, but energy efficiency is poor due to waste heat requiring cooling systems
Solution Approach 1:
The field emitters operate by periodic cycling of the pyroelectric or piezoelectric crystal through temperature or strain changes. This periodic activation generates electron pulses that strike the target to produce x-rays, allowing the system to operate efficiently in pulsed mode and minimize waste heat generation compared to continuous operation of conventional tubes.
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 enables a lightweight, portable, and robust x-ray source with controlled x-ray production, suitable for remote locations and applications requiring cost-effective, high-energy imaging, without the need for external high voltage or radioactive materials.
Implementation Method 1
A compact, self-contained x-ray source using a pyroelectric or piezoelectric crystal with micrometer-scale field emitters
Implementation Method 2
A compact, self-contained x-ray source using a pyroelectric or piezoelectric crystal with micrometer-scale field emitters
Implementation Method 3
electrons that impinge on a bremsstrahlung target to produce x-rays
Data Source
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AI summary
An apparatus for producing x-rays for use in imaging applications is provided having a piezoelectric or pyroelecthc crystal with an upper surface and a conducting film coating the upper surface of the crystal. The crystal includes a plurality of field emitters formed as micrometer-scale exposed regions in the crystal having a one or more sharp peaks or ridges. In one embodiment, parallel trenches within the crystal form a wedge shaped emitter. The crystal is alternately heated and cooled over a period of several minutes with a heater/cooler adjacent the crystal so that spontaneous charge polarization occurs in the crystal. The spontaneous charge polarization causes a perpendicular electric field to arise on the crystal's top and bottom faces, in which case at the exposed surface of the crystal the electric field is enhanced by the sharp peaks or ridges, thereby causing field emission of surface electrons from that location. X-rays are produced when the emitted electrons strike a target material located adjacent to the emitting face, and may be filtered or collimated.