Pitch-Gradient Lamp Filament for Stable Heat Profiles
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Solution Overview
Problem
Conventional heat lamps used in substrate processing chambers experience deformation due to metal fatigue from heating and cooling, leading to inconsistent heat profiles and reduced lifespan, which affects the quality of deposited materials.
Innovation Solution
A heat lamp filament with a pitch gradient is designed, where the pitches between coils increase in a specific pattern, maintaining integrity and reducing deformation, and is housed in a gas-filled bulb to extend the lamp's usable lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a conventional lamp filament is used, then the lamp can provide heating function, but the filament deforms due to metal fatigue from heating and cooling cycles, reducing lifespan and heat profile consistency
Solution Approach 1:
The patent applies local quality by creating a pitch gradient along the filament length, where different sections have different coil pitches. The pitch transitions from a first value at one end to a second value at the other end, allowing different portions of the filament to experience different thermal expansion and stress characteristics, thereby reducing overall deformation and extending lifespan while maintaining heat profile consistency.
Solution Approach 2:
The patent changes the geometric parameter of the filament by varying the pitch between coils along its length. This parameter change creates a gradient structure that compensates for thermal expansion and reduces stress concentration during heating and cooling cycles, directly addressing the metal fatigue problem and improving both lifespan and reliability.
2Duration of action of stationary object
If replacement lamps are used, then the lamp can continue to provide heating function, but replacement lamps introduce heat profile variations due to differences between used and replacement lamps
Solution Approach 1:
The pitch gradient structure creates a more robust filament design that is less sensitive to manufacturing tolerances and installation variations. By distributing thermal stress across different pitch regions, the filament maintains more consistent performance across multiple replacement cycles, reducing heat profile variations between used and replacement lamps.
3Reliability
If a pitch gradient filament is used, then the filament maintains integrity and reduces deformation, but the filament structure becomes more complex
Solution Approach 1:
The patent implements a pitch gradient by gradually changing the coil pitch parameter along the filament length. This can be achieved through controlled winding processes where the pitch transitions smoothly from one end to the other, maintaining structural integrity while avoiding abrupt geometric changes that would increase complexity. The gradient approach provides a balanced solution between performance improvement and manufacturing feasibility.
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 pitch gradient filament maintains its shape and functionality for up to 20-25% longer than conventional lamps, ensuring consistent heat profiles and reducing the frequency of replacements, thereby improving material deposition uniformity and reducing costs.
Implementation Method 1
Conventional heat lamps used in substrate processing chambers experience deformation due to metal fatigue from heating and cooling
Implementation Method 2
housed in a gas-filled bulb to extend the lamp's usable lifespan
Data Source
AI summary
Examples disclosed herein relate to a to a pitch gradient in a lamp filament, and a method of making. In one implementation, a lamp has a bulb filled with a gas. A filament is disposed within the bulb. The filament has a plurality of coils that include a first coil having a first point. The plurality of coils includes a second coil having a second point, and a third coil having a third point. The pitch gradient is defined by a first pitch between the second point and the first point, and a second pitch between the third point and the second point. The second pitch is greater than the first pitch. The second point is 360 degrees away from the first point. The third point is 360 degrees from the second point. A terminal coil is electrically coupled to at least the first coil, the second coil, and the third coil.