Rounded Closed Curve Memory Cell for Inkjet Printheads

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Solution Overview

Problem

Existing programmable read-only memory (PROM) chips, particularly those using fuse technology in N-channel metal-oxide semiconductor (NMOS) chips, face issues such as unreliability, difficulty in correcting programming errors, and potential damage to inkjet printheads due to large and unreliable fuses, which can cause ink blockages and poor printing quality.

Innovation Solution

The development of electronically programmable read-only memory (EPROM) devices that replace fuses with transistor structures and floating gates, allowing for programming via hot carrier injection, eliminating the need for fuses and improving reliability and efficiency by using rounded closed curve structures for the channel and floating gate to enhance uniformity and programming efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fuse technology is used in NMOS chips for PROM, then memory storage is achieved, but reliability deteriorates and programming errors cannot be corrected

Engineering Contradiction:

Improvememory reliabilityVSAvoidprogramming error correction

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent extracts the programming error correction capability from the system by introducing a separate verification and correction mechanism that operates independently from the original programming process, allowing errors to be detected and fixed without reprogramming the entire device

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the electrical parameters during operation by applying different voltage levels and current configurations to enable verification modes and correction operations, transforming the memory cell's electrical characteristics to support error correction functionality

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If fuses are used for memory storage, then simple structure is achieved, but harmful factors increase due to metal debris causing ink blockages

Engineering Contradiction:

Improvememory structureVSAvoidmetal debris in ink

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the fuse element entirely from the system and replaces it with a transistor-based memory cell that does not produce metal debris, extracting the harmful factor elimination as a primary function of the redesign

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/physical fuse burning process with an electrical field-based transistor switching mechanism, substituting a mechanical system that produces debris with an electrical system that does not

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If rectangular channel and floating gate structure is used in EPROM, then manufacturing is simplified, but programming efficiency decreases by 20%

Engineering Contradiction:

Improvechannel and gate structureVSAvoidprogramming efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies rounded corners to the rectangular channel and floating gate structure, transforming sharp angles into curved transitions that improve the uniformity of electric field distribution and enhance programming efficiency while maintaining overall rectangular geometry for manufacturability

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Adaptability or versatility

If fuses are used in inkjet printheads, then memory function is achieved, but inkjet performance deteriorates due to orifice layer damage

Engineering Contradiction:

Improvememory function in inkjetVSAvoidorifice layer damage

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the fuse element that causes orifice layer damage and replaces it with a transistor-based memory cell that operates without damaging the inkjet orifice structure, eliminating the harmful interaction between memory programming and inkjet functionality

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a transistor structure as an intermediary between the control electronics and the inkjet orifice, providing memory functionality without direct interaction between programming operations and the orifice layer

Inventive Principle:

Principle #24Intermediary (Mediator)

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 EPROM solution provides reliable and efficient memory storage without the drawbacks of fuse-based systems, enabling cumulative data storage and improved programming efficiency, with a 20% increase in programming efficiency over traditional rectangular channel and floating gate EPROM cells, and the ability to track cumulative quantities or control analog circuits.

Implementation Method 1

programming via hot carrier injection

Methodology Applied

Scientific EffectHot carrier injection:

Data Source

PatentUS10504910B2Memory cell having closed curve structure

Publication Date: 2019.12.10 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

A memory cell for a printhead includes a substrate with a source and a drain. The substrate further includes a channel located between the source and the drain and surrounding the drain. The drain can include a first rounded closed curved structure. The memory cell can include a floating gate and a control gate. The floating gate can include a second rounded closed curve structure located above the channel and below the control gate. The control gate is capacitively coupled to the floating gate.