Driver IC Segmentation for Liquid Ejecting Head Units
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Solution Overview
Problem
The challenge is to reduce the nozzle arrangement pitch to increase resolution in liquid ejecting devices while minimizing interference between the actuator substrate and the driver IC, which can cause erroneous ink ejection and deteriorate product quality.
Innovation Solution
A head unit configuration with a driver IC that includes separate blocks for applying drive and hold signals to actuators, with the hold signal block situated between the drive signal blocks and formed over a non-doped region, and isolated by a buffer area, reduces terminal density and noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the driver IC is mounted on the actuator substrate to increase integration, then the resolution is improved, but interference between the actuator substrate and driver IC causes malfunction and deteriorates product quality
Solution Approach 1:
The driver IC is divided into three separate blocks (first block for drive signals to first array, second block for drive signals to second array, third block for hold signals) that are spatially separated and mounted on different regions of the actuator substrate. This segmentation reduces interference between different signal paths while maintaining high integration for improved resolution.
2Manufacturing precision
If the nozzle arrangement pitch is reduced to increase resolution, then the manufacturing precision is improved, but the connection pitch with driver IC becomes smaller increasing interference
Solution Approach 1:
Different regions of the driver IC are assigned different functions with different signal characteristics. The first and second blocks handling high-voltage drive signals are positioned away from the third block handling low-voltage hold signals. This local differentiation allows reduced nozzle pitch while maintaining signal integrity by minimizing interference in specific local areas.
3Device complexity
If the driver IC integrates all functions to reduce connection pitch, then the degree of integration is improved, but noise from current flow affects other circuits
Solution Approach 1:
The third block that handles hold signals and experiences large current flow is extracted and positioned separately from the first and second blocks that handle drive signals. This extraction removes the noise source from proximity to sensitive circuits, allowing high integration without compromising signal quality.
Solution Approach 2:
A buffer area is introduced between the third block and the first/second blocks to act as an intermediary zone. This buffer region isolates the high-current third block from the sensitive drive signal blocks, reducing noise coupling while maintaining compact integration.
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 decreases noise effects and facilitates connection, improving ink ejection accuracy and product quality by reducing interference and allowing for closer nozzle arrangement, thereby enhancing resolution.
Implementation Method 1
An ejection section that ejects the liquid typically includes a plurality of piezoelectric elements (piezo elements), and is configured so that a predetermined amount of liquid (e.g., ink) is ejected from a nozzle at a predetermined timing when a drive signal is supplied to one end of each piezoelectric element
Data Source
AI summary
A head unit includes: a structure; and a driver IC, the structure including a plurality of ejection sections, the plurality of ejection sections being divided into a first array and a second array that differs from the first array, each of the plurality of ejection sections including an actuator and ejecting a liquid corresponding to a drive signal applied to one end of the actuator, the driver IC including: a first block that is electrically connected to one end of the actuator included in the first array, and applies the drive signal to the actuator included in the first array; a second block that is electrically connected to one end of the actuator included in the second array, and applies the drive signal to the actuator included in the second array; and a third block that is electrically connected to the other end of the actuator included in the first array and the other end of the actuator included in the second array, and applies a hold signal to the actuator included in the first array and the actuator included in the second array, the driver IC being mounted on the structure so as to seal the actuator included in the first array and the actuator included in the second array, and the third block being situated between the first block and the second block when viewed perpendicular to a mounting surface of the driver IC that is mounted on the structure.