How a Tiny Sensor Uses an Extra Weight to Detect Motion
This patent describes a miniature sensor that detects movement or force by measuring changes in electrical signals between tiny plates, featuring a clever extra weight to make it more sensitive.
Original patent title: “Mems sensor, method of manufacturing thereof, and electronic apparatus”
This patent describes a miniature sensor that detects movement or force by measuring changes in electrical signals between tiny plates, featuring a clever extra weight to make it more sensitive. Owned by Seiko Epson with 13 claims and 40 forward citations, and it is expected to expire in 2030.
Coverage
What does this patent actually cover?
This patent details a tiny sensor, known as a MEMS sensor, designed to detect physical changes like movement or acceleration. It includes a stationary "fixed portion" and a "movable weight portion" connected by a flexible "elastically deformable portion," acting like a miniature spring (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). The movable part has "movable electrode portions" that sit opposite "fixed electrode portions." When the sensor moves, the movable weight shifts, changing the gap between these electrodes, which then alters an electrical signal. The core innovation is an "additional weight portion" attached to the movable part, which helps improve the sensor's performance. For instance, this sensor could be built into a smartwatch to accurately track your steps by sensing subtle wrist movements. The patent also describes a manufacturing method that involves etching a material from both its top and bottom surfaces to create this complex structure (Claim 11).
The gap
What does this patent NOT cover?
- Does not cover MEMS sensors that lack an "additional weight portion" connected to the movable weight portion.
- Does not cover sensors where the fixed and movable electrodes are not arranged to face each other in a capacitive sensing setup.
- Does not cover manufacturing processes that do not involve etching the substrate from both sides to form the additional weight portion.
- Does not cover sensors that use different detection principles, such as piezoelectric or thermal, instead of capacitive sensing.
- Does not cover sensors where the movable element is not coupled to the fixed portion via an elastically deformable component.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The clever bit is adding an "additional weight portion" to the movable part of the sensor. This seemingly simple addition allows engineers to fine-tune the sensor's mass and how it responds to forces, making it more sensitive or stable without drastically changing the overall sensor design.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Accelerometers in smartphones
Gyroscopes in drones
Inertial measurement units (IMUs) in robotics
Motion sensors in fitness trackers
Automotive airbag deployment sensors
Why it matters
The bigger picture
MEMS sensors are fundamental components in countless modern electronic devices, enabling features like screen rotation, activity tracking, and impact detection. Seiko Epson, the assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is a major player in precision components. This patent contributes to the ongoing refinement of these tiny sensors, aiming to make them more accurate, reliable, and sensitive, which directly impacts the performance of consumer electronics and industrial applications.
Filed
November 17, 2010
Market context
Who's building on this
Companies in this space
Seiko Epson continues to be a significant developer and manufacturer of MEMS devices, including accelerometers, gyroscopes, and pressure sensors, used in various applications from consumer electronics to industrial equipment. Other major players in the MEMS sensor market, such as Bosch Sensortec, STMicroelectronics, and TDK InvenSense, are also continuously innovating in sensor design and manufacturing techniques to improve performance.
Market impact
This patent contributes to the ongoing evolution of MEMS sensor technology, which has allowed for the miniaturization and widespread adoption of motion sensing capabilities across numerous product categories. By improving sensor characteristics like sensitivity and stability, such innovations enable more accurate and reliable data collection, supporting the development of advanced features in smartphones, wearables, and autonomous systems. It helps refine the core components that underpin much of the modern connected world.
Claim 1 — Plain English
What this patent covers
This patent details a tiny sensor, known as a MEMS sensor, designed to detect physical changes like movement or acceleration. It includes a stationary "fixed portion" and a "movable weight portion" connected by a flexible "elastically deformable portion," acting like a miniature spring (Claim 1). The movable part has "movable electrode portions" that sit opposite "fixed electrode portions." When the sensor moves, the movable weight shifts, changing the gap between these electrodes, which then alters an electrical signal. The core innovation is an "additional weight portion" attached to the movable part, which helps improve the sensor's performance. For instance, this sensor could be built into a smartwatch to accurately track your steps by sensing subtle wrist movements. The patent also describes a manufacturing method that involves etching a material from both its top and bottom surfaces to create this complex structure (Claim 11).
The clever bit
The clever bit is adding an "additional weight portion" to the movable part of the sensor. This seemingly simple addition allows engineers to fine-tune the sensor's mass and how it responds to forces, making it more sensitive or stable without drastically changing the overall sensor design.
What it does not cover
- Does not cover MEMS sensors that lack an "additional weight portion" connected to the movable weight portion.
- Does not cover sensors where the fixed and movable electrodes are not arranged to face each other in a capacitive sensing setup.
- Does not cover manufacturing processes that do not involve etching the substrate from both sides to form the additional weight portion.
- Does not cover sensors that use different detection principles, such as piezoelectric or thermal, instead of capacitive sensing.
- Does not cover sensors where the movable element is not coupled to the fixed portion via an elastically deformable component.
Patent timeline
Application submitted to the patent office
Patent enters public domain
PatentBrief Score
Impact Score
Moderate
Citation count
32/40
Moderately cited
Claim breadth
9/20
Moderate scope
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$79K – $252K
Midpoint $158K · 4.3 yr remaining · industry ×1.5
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
13 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Yoda, M. How a Tiny Sensor Uses an Extra Weight to Detect Motion (U.S. Patent No. 20,110,120,221). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/20110120221/mems-sensor-method-of-manufacturing-thereof-and-electronic-apparatus
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How a Tiny Sensor Uses an Extra Weight to Detect Motion cover?
This patent describes a miniature sensor that detects movement or force by measuring changes in electrical signals between tiny plates, featuring a clever extra weight to make it more sensitive.
Who owns patent US 20110120221?
This patent is owned by Seiko Epson.
When does this patent expire?
This patent is expected to expire on November 17, 2030, when the invention enters the public domain.
What is patent US 20110120221 cited by?
This patent has been cited by 40 later patents that build on its ideas.
What problem does this patent solve?
MEMS sensors are fundamental components in countless modern electronic devices, enabling features like screen rotation, activity tracking, and impact detection. Seiko Epson, the assignee, is a major player in precision components. This patent contributes to the ongoing refinement of these tiny sensors, aiming to make them more accurate, reliable, and sensitive, which directly impacts the performance of consumer electronics and industrial applications.
What does this patent NOT cover?
Does not cover MEMS sensors that lack an "additional weight portion" connected to the movable weight portion.
Patent monitoring