Ceramic Heater Uniform Heat Distribution via Planar Resistive Design
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Solution Overview
Problem
Conventional ceramic heaters face challenges in achieving uniform heat distribution due to local heat generation by linear or strip-shaped first resistive elements, which affects the desired heating state of the target object, and altering the resistive element's shape to increase its area to suppress heat generation compromises the resistance value of adjacent heating resistors.
Innovation Solution
A ceramic heater design featuring a planar first resistive portion within an inner circle and a linear or strip-shaped second resistive portion extending radially, with a connecting portion, embedded in a ceramic substrate, where the second heating resistor is positioned below both, allowing sufficient carbon reaction and maintaining desired resistance values, and the first resistive portion occupies a larger area to reduce electrical resistance and promote uniform heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the first resistive element is made linear or strip-shaped to enable local heat generation, then heat generation capability is improved, but heat uniformity deteriorates
Solution Approach 1:
The heating resistor is divided into multiple regions with different resistive element configurations: the first region uses a linear first resistive element for localized heating, while the second region uses a planar first resistive element for uniform heat distribution. This local quality differentiation allows each region to perform its specific heating function optimally, resolving the contradiction between localized heat generation and overall heat uniformity.
2Stability of the object's composition
If the occupation area of the first resistive element is increased to suppress local heat generation, then heat uniformity is improved, but the resistance value of adjacent heating resistors deteriorates
Solution Approach 1:
The heater is segmented into multiple heating resistors with distinct functional regions. The first heating resistor uses a planar first resistive element with large occupation area to suppress local heat generation and improve heat uniformity, while the second heating resistor maintains a conventional structure to ensure desired resistance value. This segmentation allows each component to optimize its performance without compromising the other.
3Stability of the object's composition
If a planar first resistive portion is used to increase occupation area and reduce electrical resistance, then heat uniformity is improved, but the complexity of the heating resistor structure increases
Solution Approach 1:
The planar first resistive element is implemented only in the second region where uniform heat distribution is needed, while the first region maintains a simpler linear structure. This localized application of the planar design minimizes the increase in structural complexity while achieving the desired heat uniformity in the critical second region.
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
This configuration achieves uniform heat distribution on the ceramic substrate by suppressing heat generation from the first resistive element and ensuring the second heating resistor maintains a desired resistance value, effectively heating the target object in a desired state.
Implementation Method 1
the first resistive portion is arranged in a planer shape... the electrical resistance of the first resistive portion is lowered so as to suppress heat generation in the region in which the first resistive portion is arranged
Implementation Method 2
During the sintering, a carbon component contained in the ceramic material is reacted with the electrode and the heating resistors. Consequently, the heating resistors show respective desired resistance values.
Data Source
AI summary
Disclosed is a ceramic heater, which includes: a disc-shaped ceramic substrate with top and bottom surfaces; and a planar electrode and first and second heating resistors embedded in the ceramic substrate in this order from top to bottom. In top view, the first heating resistor has: a planer first resistive portion arranged inside a first imaginary circle defined by an outermost circumferential contour of the planer electrode; a linear or strip-shaped second resistive portion arranged outward of the first resistive portion in a radial direction of the ceramic substrate and extending along a circumferential direction of the ceramic substrate; and a connecting portion connecting the first and second resistive portions to each other; and the second heating resistor is arranged inside a second imaginary circle defined by an innermost circumferential contour of the second resistive portion.