Element Substrate Stacked Resistor Layers
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Solution Overview
Problem
Existing liquid ejection heads with heat generating resistors face significant variations in resistance value due to repeated driving, which reduces their lifespan and affects ejection performance, especially when the resistors have high resistance values.
Innovation Solution
A stacked structure of multiple resistor layers made of different metal silicon nitrides is used, where each layer has varying silicon content and metal elements, allowing for distinct resistance value variation characteristics to be utilized, thereby suppressing overall resistance variations without imposing an upper limit on specific resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a heat generating resistor with high resistance value is used, then the liquid ejection speed is increased, but the resistance value variations due to repeated driving become larger
Solution Approach 1:
The heat generating resistor is divided into multiple resistor layers (first resistor layer and second resistor layer) with different material compositions. Each layer has distinct resistance characteristics that compensate for variations when driven repeatedly, allowing high resistance values for fast ejection while maintaining stability through the segmented structure.
Solution Approach 2:
Different regions of the resistor (first and second resistor layers) are given different local qualities through varying metal silicon nitride compositions. The first layer contains metal silicon nitride with specific silicon content while the second layer contains metal silicon nitride with different silicon content or different metal elements, creating localized resistance characteristics that collectively stabilize the overall resistance.
2Productivity
If the resistance value of heat generating resistor is increased, then the ejection performance is improved, but the variations in resistance value due to repeated driving increase
Solution Approach 1:
The resistor is segmented into multiple layers with different compositions to achieve high overall resistance for improved ejection performance while each layer's specific composition compensates for resistance variations, maintaining consistency through the segmented architecture.
Solution Approach 2:
The heat generating resistor uses composite material structure with multiple resistor layers made of different metal silicon nitride compositions. This composite approach enables high resistance values for better ejection performance while the material diversity stabilizes resistance consistency by distributing variation effects across different material properties.
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 effectively reduces resistance variations in heat generating resistors, even at high resistance levels, enhancing the longevity and reliability of liquid ejection heads by stabilizing resistance values and preventing excessive burden or ejection failures.
Implementation Method 1
heat generating resistor that generates thermal energy for ejecting a liquid
Data Source
AI summary
Provided is an element substrate with suppressed variations in resistance though having a high resistance. In an element substrate equipped with a heat generating resistor that generates thermal energy for ejecting a liquid, the heat generating resistor is a stacked structure having stacked a plurality of resistor layers including a first resistor layer and a second resistor layer containing a metal silicon nitride and the first resistor layer and the second resistor layer are different from each other in at least one of a silicon content in the metal silicon oxide and a metal element contained in the metal silicon nitride.