On-Die Crack Detection Circuits for Printheads
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Solution Overview
Problem
Integrated circuit (IC) die, such as printhead die for ink jet printers, can be damaged during manufacture and/or use, with faults like cracks and fractures not easily detectable, leading to premature failure and customer dissatisfaction, especially when multiple ICs are incorporated into a module.
Innovation Solution
The implementation of crack detection circuits fully contained on the printhead die, which include multiple crack detectors, switches, and analog-to-digital converters to measure impedance, allowing for crack detection throughout the manufacturing process and during operation without the need for external hardware or electrical interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external measurement hardware and electrical interconnects are used for crack detection, then measurement capability is provided, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the crack detection functionality directly into the printhead die by integrating crack detectors, switches, and analog-to-digital converters onto the same substrate. This eliminates the need for separate external measurement hardware and complex electrical interconnects, as the detection circuitry becomes an intrinsic part of the printhead assembly.
Solution Approach 2:
The printhead die performs its own self-diagnosis by incorporating crack detection circuits that can autonomously monitor for cracks and fractures. The integrated switches and ADCs enable the printhead to self-assess its structural integrity without requiring external testing equipment, allowing for autonomous fault detection during operation.
2Device complexity
If crack detection circuits are integrated on the printhead die, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The crack detection functionality is segmented into discrete, modular components including individual crack detectors, switches, and analog-to-digital converters that are independently fabricated and then integrated onto the printhead die. This segmentation allows each component to be optimized separately during manufacturing while maintaining overall system functionality, reducing the cumulative impact of integration variations.
3Reliability
If multiple crack detectors are implemented on each printhead, then detection coverage is improved, but manufacturing cost increases
Solution Approach 1:
The crack detection circuitry is designed with universal components that serve multiple functions. The same switches and ADCs used for crack detection can also be utilized for other printhead control and monitoring functions, maximizing the utility of each manufactured component. This multi-functionality justifies the additional manufacturing cost by providing enhanced detection capabilities without proportionally increasing overall system 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
Enables reliable crack detection at all stages of the printhead's lifecycle, from manufacturing to operation, reducing premature failures and enhancing reliability in multi-die modules by performing measurements on-die with existing communication protocols, thus eliminating the need for additional system-level hardware or firmware.
Implementation Method 1
Each ADC measures impedance of at least one of the crack detectors and outputs digital measurements representing the impedance
Data Source
AI summary
Crack detection circuits for printheads are described. In an example, a crack detection circuit for at least one printhead, includes: crack detectors formed on the at least one printhead; switches selectively coupling the crack detectors on each printhead to a communication bus; and a configuration circuit on each printhead coupled to control inputs of the respective switches, each configuration circuit responsive to a crack detection configuration input to control the respective switches.