Deep Channel Cathode Assembly for X-ray Tube Focal Spot Control
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Solution Overview
Problem
Current cathode assemblies for X-ray tubes face challenges in achieving small focal spot sizes without relying on external magnetic or electric fields, which increases manufacturing costs and degrades yield due to sensitivity to filament set height and channel radius.
Innovation Solution
The cathode assembly features deep channels configured in the cathode cup surface to hold filaments, allowing for the generation of small focal spots by controlling electron beam trajectories and reducing sensitivity to filament set height and channel radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If external magnetic or biasing electric fields are used to achieve small focal spots, then focal spot size is reduced, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the need for external magnetic or biasing electric fields by incorporating the field-generating function directly into the cathode cup structure through deep channels with specific geometric configurations. The cathode cup geometry itself generates the necessary electron focusing effect, removing the need for separate external field-generating components and their associated manufacturing costs.
Solution Approach 2:
The patent changes the geometric parameters of the cathode cup, specifically implementing deep channels with optimized depth, width, and curvature radii. These parameter changes create an internal electron focusing mechanism that achieves small focal spots without requiring external magnetic or electric fields, thereby reducing manufacturing complexity and cost.
2Manufacturing precision
If filament set height is precisely controlled to achieve small focal spots, then focal spot size is reduced, but manufacturing yield degrades
Solution Approach 1:
The patent changes the channel geometry parameters, specifically the depth and cross-sectional dimensions of the cathode cup channels. This parameter change creates a geometric focusing effect that is less sensitive to filament set height variations, allowing for smaller focal spots while maintaining higher manufacturing yield through relaxed tolerances.
Solution Approach 2:
The deep channel geometry acts as a pre-configured structure that compensates for potential filament positioning variations. The specific channel dimensions and curvature profiles are designed beforehand to provide a cushioning effect against manufacturing tolerances, ensuring consistent focal spot sizes even with variations in filament set height.
3Manufacturing precision
If channel radius is precisely controlled to achieve small focal spots, then focal spot size is reduced, but manufacturing cost increases
Solution Approach 1:
The patent optimizes the channel radius parameter within a specific range that achieves small focal spots while being less sensitive to precise manufacturing tolerances. By selecting appropriate radius values for the deep channel geometry, the patent balances focal spot quality with manufacturing feasibility, reducing overall device complexity and cost.
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
Enables the production of focal spots smaller than 0.3 nominal size with increased tolerance in filament set height and diameter, simplifying manufacturing and extending X-ray tube life while maintaining control over focal spot dimensions.
Implementation Method 1
The filaments are energized so that electrons accelerate towards the anode to form focal spots
Data Source
AI summary
An improved cathode assembly is disclosed. The improved cathode assembly provides a deep channel for holding filament that enables generation of small focal spots, but is not limited in achieving larger focal spot sizes. The cathode assembly includes at least one deep channel and a filament arranged in a deep channel. The deep channel is configured in a cathode cup surface of the cathode assembly. The filament is arranged in the deep channel for enabling emission of electron beams from the cathode assembly.