Discretely Addressable X-ray System Using Nano Emitters
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Solution Overview
Problem
Conventional large-area X-ray systems face challenges in achieving uniform X-ray flux distribution due to high operation temperatures, inefficient electron emission, and complex mechanical systems, which lead to increased size, energy consumption, and non-uniform X-ray emission.
Innovation Solution
A discretely addressable large-area X-ray system utilizing a cathode with fine patterned nano emitters and a gate for focusing electrons, where transistors connected to each nano emitter allow for precise control of electron emission through pulse voltage, enabling uniform X-ray flux distribution over a large area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal electron emission using a filament is used, then electrons can be emitted, but the operation temperature becomes very high (about 1500°C), shortening filament lifespan and increasing energy consumption
Solution Approach 1:
The patent changes the emission mechanism from thermal emission to field emission, fundamentally altering the operating parameters from high temperature (1500°C) to room temperature or low temperature operation. This parameter change resolves the contradiction by enabling electron emission without high temperature, thereby extending filament lifespan and reducing energy consumption
Solution Approach 2:
The patent replaces the thermal field (heating filament) with an electric field (applying voltage to gate) to induce electron emission. This substitution of the emission mechanism eliminates the need for high temperature operation, resolving the contradiction between reliability and temperature
2Speed
If thermal electron emission using a filament is used, then electrons can be emitted, but the response time becomes very slow due to warm-up time required
Solution Approach 1:
The patent changes the emission mechanism from thermal to field emission, eliminating the warm-up phase entirely. Field emission can be activated immediately upon applying voltage, achieving fast response time and eliminating warm-up time loss
Solution Approach 2:
The patent employs pulsed voltage application to the gate, enabling electrons to be emitted only when needed. This periodic action allows the system to switch on and off rapidly without warm-up time, resolving the contradiction between speed and time loss
3Area of stationary object
If multiple X-ray tubes using Nano emitters are arranged for large area, then coverage area increases, but the tubes output different flux of X-rays making uniformity difficult to achieve
Solution Approach 1:
The patent segments the large-area cathode into multiple independently controllable regions, each with its own transistor control. This segmentation allows individual adjustment of each region's electron emission, enabling uniform X-ray flux across the entire large area by compensating for variations in each segment
Solution Approach 2:
The patent applies local quality control by allowing different voltage levels to be applied to different regions of the cathode through individual transistor control. This enables each region to be optimized for uniform electron emission, resolving the flux uniformity issue across the large area
4Manufacturing precision
If a physically moving system is used to achieve uniform X-ray distribution, then X-ray uniformity can be improved, but the system size increases and structural efficiency degrades
Solution Approach 1:
The patent replaces the mechanical moving system with an electronic control system. Instead of physically moving components to achieve uniformity, the system uses electronic control of electron emission from multiple cathode regions, eliminating the need for large mechanical structures while achieving X-ray flux uniformity
Solution Approach 2:
The patent employs dynamic control of electron emission through transistor switching, allowing rapid adjustment of emission levels from different cathode regions. This dynamic electronic control achieves uniformity without mechanical movement, resolving the contradiction between precision and device complexity
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 system achieves efficient and uniform X-ray emission with reduced energy consumption and extended emitter lifespan, allowing for targeted imaging and simplified implementation in various applications.
Implementation Method 1
The nano emitters are conductive emitters having a sharp end and obeying a field emission principle whereby the emitter emits electrons in a vacuum state in response to an electric field
Implementation Method 2
an anode disposed over the electron emitter for accelerating and colliding the electrons emitted from the nano emitters to generate X-rays
Implementation Method 3
accelerating and colliding the electrons emitted from the nano emitters to generate X-rays
Data Source
AI summary
A discretely addressable large-area X-ray system is provided. The large-area X-ray system can output a uniform flux of X-rays over a large area using discrete addressing operation of transistors connected to cathodes of electron emitters. Thus, when applied to a medical device, the system can minimize damage inflicted upon the human body because it enables effective imaging of only a desired specific portion of the body. Furthermore, the large-area X-ray system can be simply implemented by current switching using transistors. Thus, the system can be very easily applied to other applications.