Thermal Head U-Shaped Resistor Single Patterning
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Solution Overview
Problem
The existing thermal head manufacturing process faces challenges in accurately determining the planar shapes of resistor layers, leading to variations in resistance due to deviations in patterning steps, which affects the performance and reliability of the thermal head.
Innovation Solution
A thermal head design featuring a resistor layer with a U-shape covered by an insulating barrier layer, where the width and length dimensions are simultaneously determined through a single patterning step, and a folded electrode structure with a connection portion of 5 μm or less to ensure accurate heat distribution and prevent printing damage, along with tapered end surfaces for improved electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate patterning steps are performed for length dimension L' and width dimension W' of the heating resistor, then the manufacturing process can be completed, but resistance variation increases due to patterning deviation
Solution Approach 1:
The patent combines the determination of both length dimension L' and width dimension W' into a single patterning step. By forming opening portions that simultaneously define both dimensions of the heating resistor in one operation, the patent eliminates the sequential patterning steps that cause cumulative deviations, thereby achieving uniform resistance across all heating resistors while simplifying the manufacturing process
2Reliability
If the Al electrode layer E is made thick (approximately 1 μm) to decrease electrode resistance, then electrode resistance is reduced, but step portions are formed at the boundaries causing contact efficiency degradation
Solution Approach 1:
The patent performs preliminary polishing of the abrasion-resistance protective layer surface in the region corresponding to the step portions before final assembly. This preliminary surface treatment removes the step portions formed by the thick Al electrode layer, ensuring flat contact surfaces that improve contact efficiency with the print medium while maintaining the thick electrode design for low resistance
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 approach results in a high-performance thermal head with reduced resistance variation and improved printing quality by ensuring accurate planar shapes and efficient heat distribution, while minimizing manufacturing steps and costs.
Implementation Method 1
a heating resistor 105 (105a and 105b) which generates heat by electricity supply
Data Source
AI summary
A method for manufacturing a thermal head is provided which includes the steps of forming a resistor layer and an insulating barrier layer, patterning the above two layers to form aligned heating resistors, forming a solid electrode layer over the heating resistors and the like, and partly removing the solid electrode layer to form opening portions and electrode layers for supplying electricity to the heating resistors. In the patterning step, part of the resistor layer and part of the insulating barrier layer, which are outside a heat generating area, are simultaneously removed to form the heating resistors having a planar U shape composed of a pair of effective heating portions and a connection portion connecting the above pair, the effective heating portions and the connection portion each having a predetermined length and width. The length of the connection portion is set to 5 μm or less.