MEMS Technology At The Heart Of Omron Flow Sensors

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A major advantage of MEMS Flow Sensors is their ability to measure flow speed from 1 mm/s to 40 m/s.  To put this into perspective, this covers a range from the fluttering of a butterfly's wings to the roar of a typhoon. At the heart of the MEMS Flow Sensor, there is a tiny sensor element; the Omron MEMS Flow Sensor chip which is only 1.5 mm square by 0.4 mm thick.

Conventional flow sensors use a resistance measurement method based on a natural characteristic that causes the electrical resistance of a material to change due to changes in temperature. This method has a number of disadvantages, though, such as the high cost required for the extremely time-consuming adjustment of the resistance balance.

In contrast the Omron MEMS Flow Sensor, which by the way was the industry's first to apply this technology, utilizes an element called a thermopile that converts thermal energy into electrical energy. This revolutionary method delivered a variety of previously nonexistent advantages, including low-cost operation because there are few adjustments required, low power consumption, and high sensitivity.
The chip’s two sets of thermopiles, located on either side of a tiny heater element, are used to measure the deviations in heat symmetry caused by gas flowing in either direction. A thin layer of insulating film protects the sensor chip from exposure to the gas. 

When there is no flow present, temperature distribution concentrated around the heater is uniform and the differential voltage over the two thermopiles is 0V (Diagram1). When even the smallest flow is present, temperature on the side of the heater facing the flow cools, and warms up on the other side of the heater - heat symmetry collapses.  The difference of temperature appears as a differential voltage between the two thermopiles, proportional to the mass flow rate.

Diagram 1. Omron was the first manufacturer to utilize thermopile technology to measure flow rate.  

Omron’s unique etching technologies (Diagram 2) were used to create a unique shape that gives their flow sensing chip it’s superb characteristics by  providing a larger sensing area compared to Conventional Silicon Etching in the same volume.  This cavity design enables efficient heating with low power consumption.

To keep the heater temperature above that of the gas being measured, temperature compensating circuitry, which could be described as an “expanded bridge circuit” is incorporated in all Omron flow sensors (except the very economical D6F-V clogged filter/air velocity sensor).  This expanded circuit arrangement provides improved temperature characteristics over an ordinary bridge circuit (Diagram 3). 

Furthermore, it allows for a factory-adjustable cross point of the temperature characteristic resulting in higher output stability with fluctuating ambient temperatures. 

For optimal mass flow readings across the MEMS chip, a uniform, laminar flow through the sensor is highly desirable.  Omron’s in-line mass flow sensors, such as the D6F-01/02/03/05/10/20/50 series, incorporate a set of screens in the sensor inlets to accomplish this, resulting in high repeatability.  Pulsing flows can also present a problem for mass flow measurement.  The D6F-01A/02A series uses an orifice in the outlet side of the sensor to buffer such flows (Diagram 4), often eliminating the need for an external buffer tank.

With the advent of this MEMS technology one must seriously consider taking utilizing these flow sensors. They deliver superior repeatable flow rate measurement, lower applied cost since calibration by the customer is not necessary (they are individually calibrated at the factory), low power consumption and high sensitivity. Omron has a team of experts ready to help you with any of your design challenges. View ALL of Omron's flow sensors by visiting the product page.

Full Set of Services from Development to Manufacturing

OMRON's Minakuchi Factory in Shiga Pref. has the extensive experience in the field of MEMS Foundry for volume manufacturing which enables full set of services from development to manufacturing, and has shipped 25,000k pieces of MEMS products in total by 2006.
In addition, our new foundry (incorporated in April, 2007 in Yasu, Shiga Pref.) possesses Japan's first mass production line for 8 inches.
We have a variety of services to meet requirements from 4-5 inch wafers (with our conventional factory) to 8 inches.

Bulk/Surface Micromachining technology and Facilities

In addition to the common processes of manufacturing semiconductors - Bipolar Si Line, CMOS Line, OMRON offers MEMS technology and factory for Bulk Micromachining, such as Anodic Bonding, ECE, Deep RIE, and lines for Glass only, which differentiate from the conventional processes.

OMRON has long time experience in volume production for Anodic Bonding and ECE.
We have the technology and facilities for Surface Micromachining, with Surface MEMS processing and monolithic MEMS processing.

In contrast to the two-dimensional structure of integrated circuits, MEMS technology produces three-dimensional semiconductor structures with sub-micrometer precision. These smart structures yield ultra-compact, ultra-fast devices that help OMRON develop optimal new forms of sensing & control for the new age.

RF Switch Based on MEMS Technology

Mechanical RF Switching Relay Based on MEMS Technology:
Combining its long history of innovative relay products with its MEMS (Micro Electro Mechanical System) expertise, Omron has developed a new RF MEMS Switch to meet the requirements of the ATE market. Using an electrostatic drive mechanism, the switch combines the desirable HF characteristics of electromechanical relays with a life expectancy generally only found in solid state relays. Omron utilizes both 5" and 8" MEMS wafer production lines in its own foundry facilities.

Specifications
Part Number: 2SMES-01

Learn More by visitng the product page HERE.

Combining Core Competencies and
Break-Through Technologies

Omron’s optical subassembly (OSA) products are based on our Afterburner ™ technology that combines patented CWDM designs with proprietary manufacturing techniques to deliver high- performance in tiny, integrated packages. Afterburner Technology is versatile enough to work in standard packages (e.g. X2, XFP) or custom configurations.

SX51M Six Channel Bi-Di Optical Module - HDMI™ ready

The SX51M is an electrical to optical conversion module that enables an HDMITM signal to be sent uncompressed over one strand of multimode fiber. It is a plug-down module meant to be used with the customers’ choice of HDMI connector and housing.

Features
• 5 transmit lanes and 1 receive lane over 1 multimode fiber
• Compatible with HDMI™ compliant sources and sinks
• Scalable to HDMI™ 1.3a 16-bit color
• On-board hardware and firmware for HDCP/EDID functionality
• Accepts TMDS inputs directly into its 40 pin plug-down connector
• Automatic laser disable upon fiber disconnect
• Rx Module will receive the optical signal and restore it into its original electrical HDMI™ signal

Advantages
• Enables rapid design of HDMI™ extension solutions
• The HDCP encoding remains intact and unmodified throughout the entire process
• The SX51 Module converts and transmits an uncompressed HDMI™ video signal, along with the HDCP/EDID functionality,
over distances of up to 1000m, depending on data rate

Electroforming is widely used where the mechanical process is not practical due to high resolution and precision requirement. It copies superfine and complex pattern accurately.

What is electroforming?
When thick plating is done to the surface of the mother die and the electrodeposited layer flaked off, the shape which is quite opposite to the mother die is obtained.

1. The size accuracy is extremely high, and it is steady. The dimensional error of the reproduced goods is within ±1µm over 100mm, moreover, the distortion of the surface is 50µm or less.
2. The defect caused by foreign body is extremely few because of the clean room production.
3. The side can be transcribed in high accuracy. Moreover, if the matrix is a mirror finish, it is possible to use as a mirror finish without the finish processing. 4) Because the material is a nickel, hardness is high and durability is sufficient. It is possible to use as a mold for molding meta
Usage

1. Metal mold for liquid crystal display optical guided-wave devices and metal mold for non-spherical micro lens
2. Metal mold for micro Fresnel lenses
3. Stamper for optical disks such as CD and DVD