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Frequently Asked Questions

How long has Mirrorcle Technologies been around?

Mirrorcle Technologies, Inc. (MTI) was founded in 2005 as a spin-off of the Adriatic Research Institute where the core technology development began in 2001.

What does MEMS stand for?

"MEMS" stands for microelectromechanical systems, which describes a technology that allows for the manufacture of 'machines' that contain components between 1 to 100 micrometers in size (hence the prefix "micro"). MEMS devices are made possible by modified semiconductor fabrication technologies that are more commonly used for the manufacture of electronics.

What are MEMS mirrors used for?

Like any mirrors, MEMS-based mirrors are used in optical beam-steering applications, i.e. to deflect optical beams or images from one point to another in a controlled fashion.  By moving the mirror in a tip-tilt fashion optical beams can be deflected to new, arbitrary positions in space.  Applications include 3D scanning and object digitization, projection displays, laser marking and printing, image scanning, position-tracking and sensing, rapid prototyping, Light Detection And Ranging (LIDAR), and various biomedical imaging applications such as optical coherence tomography (OCT)-based imaging, among many others.

What makes Mirrorcle Technologies' mirrors unique?

Mirrorcle Technologies offers patented, gimbal-less two-axis scanning micromirror devices that are made entirely of single-crystal silicon. This results in excellent repeatability and reliability of mirror positioning, because there are no moving metals, plastics, or coils, nor do our devices contain piezoelectric or magnetic actuators prone for malfunction. Mirrorcle MEMS are made of maintenance-free, purely elastic material (single-crystal silicon, mono-Si), and they work entirely with electrostatic actuation, therefore there is no current. Our Gimbal-less two-axis scanning MEMS mirrors provide ultra low-power and fast optical beam scanning at angles of up to 32deg in both axes, while dissipating less than 1 mW of power. The linearized driving scheme and 4-quadrant addressable electrostatic comb drive design yields nearly linear voltage-angle characteristics.

Can Mirrorcle Technologies mirrors be used for point-to-point steering?

Yes. In fact, our devices are designed and optimized for point-to-point optical beam scanning. A steady-state analog actuation voltage results in a highly repeatable steady-stage analog angle of tip-tilt of the mirrors. One major advantage of our proprietary gimbal-less design is the capability to scan optical beams at equally high speeds in both axes. We offer the world's fastest and lowest power-consuming two-axis point-to-point steering mirrors (and yet capable of stopping at any set position.)

What are the available mirror sizes?

We currently offer circular mirrors ranging from 0.8 to 4.2mm in diameter as regular in-stock items.  Additionally we have offered 4.8mm and 6.4mm mirrors in development projects, and often have long, rectangular mirrors for single-axis optical line deflection. Please contact us if your application requires larger or differently shaped mirror sizes. Because our mirrors are modular in design, we are able to realize a broad variety of mirror types and sizes to perfectly fit your application needs.

What is the difference between integrated and bonded mirrors? What are the device types MTI offers?

We offer two distinct categories of devices based on mirror fabrication methodology:

Integrated mirror: An integrated mirror is monolithic, fabricated as an integral part of the overall MEMS device/actuator single-crystal silicon structure.  The mirror is later selectively metalized.  It is often 40um thick. Only smaller mirrors are integrated, usually those that have e.g. 0.8mm, 1.2mm, and 1.7mm diameter.

Bonded mirror:  A bonded mirror is fabricated separately from the MEMS device/actuator and it is a single-crystal silicon structure with excellent optical properties which can be assembled into a MEMS actuator with tip/tilt capabilities.  There are two sub-categories possible through Mirrorcle’s technology:

- Bonded mirror with no pedestal (no stand-off): The mirror is fabricated separately from the MEMS device/actuator. These mirrors are thin, have low inertia, and offer good flatness. They are bonded to the MEMS-actuator, on top of the rotating stage. Usually only smaller mirrors up to 1.2mm can be assembled this way.

- Bonded mirror with pedestal (standing off above MEMS/actuator): The mirror is fabricated separately. It is a thin plate with low inertia, but it is standing on top of a 0.3mm pedestal above the actuator. Mirror sizes of 2.0mm and larger are of this type.  This methodology allows mirrors of e.g. 6.4mm diameter which practically completely cover the underlying actuator chip.

Does Mirrorcle Technologies offer single-axis MEMS mirrors?

Single-axis MEMS mirrors naturally are considerably easier to design and fabricate and we can provide devices to almost any requirement upon request. We have realized single-axis devices for custom applications (such as HD video display), and always welcome related inquiries.  In stock items include a single-axis resonant actuator for bonded mirrors of 0.8, 1.0, or 1.2mm diameter, and a single-axis point to point actuator for bonded mirrors of 1.6mm and larger diameter.

Where are the pivot points of the typical 2-axis device types?

Our integrated mirrors are part of the overall MEMS device/actuator, which is about 40um thick. The pivot point is somewhere in the middle of that thickness, about 20um below the reflecting surface.
Bonded mirrors with no pedestal are mounted on top of the actuator tip/tilt stage, raising the reflective surface of the device.  The pivot point of bonded mirror with a 300um pedestal usually lies about 360um below its reflecting surface.

What are the typical achievable angles of your two-axis MEMS mirror devices?

Most of our devices can achieve a +/-5 degree mechanical tilt (-10 to +10 optical scan). Some device types can provide +/-7 degrees, and larger angles have been provided in applications which tolerate consequently reduced speeds.  It is practically always possible to trade off speed for additional angle, and vice versa.

Does Mirrorcle Technologies offer resonant-only MEMS mirrors?

Depending on your application, we can probably provide you with what you are looking for. We have some designs available that we have used in picoprojector applications to display video images. A single-axis device with a 0.8mm mirror has ~20kHz resonance and can do +/-8 degrees of mechanical scanning (+/-16 degrees optical).  The same device resonates around 10kHz with a 1.2mm mirror.  It is usually best to discuss such less standard requirements with us in person.

What are the scan speeds your mirrors can achieve?

In the category of point-to-point and vector scanning, our fastest (0.8mm diameter) device has a bandwidth of ~4kHz.  Each larger mirror size means a speed reduction.  There is an inverse-quadratic relationship between speed and mirror size.  Double mirror size will have approximately ¼ the speed given the same actuator size and angle capability.  Overall, our devices are by far the fastest and offer the best angles in the world in this category. One must keep in mind that these devices are not meant to be resonant devices - they are designed to have the ability to stop at any predetermined angle, and quickly switch to any other angle.

Why is the 24-pin DIP (DIP24) the standard package that comes with the development kit?

The DIP24 package is best for initial experiments because it allows for easy and safe manual device handling without tools. It can easily be mounted and removed from the zero insertion force (ZIF) socket on the MiniPCB. Quick switching of device types is thus possible in a convenient and safe manner.  Furthermore, DIP24 category fits all of our various device types and sizes.

What is a MiniPCB and why is it part of the development kit?

The MiniPCB is a small printed circuit board (PCB) with protection circuits for the MEMS device, an ON/OFF switch, and a zero insertion-force (ZIF) socket for easy handling of the chips. A 10-pin ribbon-cable connector (included in the development kit) provides connection to the amplifier's output. The MiniPCB is generally mounted on a 2DoF kinematic mount and a ½” post for easy integration in standard optical breadboarding to facilitate component alignment and setup.  It allows quick and easy switching between devices under test.

We would like to integrate your mirrors in a space-restricted application, in which the DIP-24 package will not fit. Do you offer any other packages?

We regularly offer four different types of packages: DIP24, LCC28, LCC20 and LCC18.   Datasheets of each of these varieties are available on the Support page of our website.
http://www.mirrorcletech.com/support.php
The possible package options depend on the size of the MEMS chip (actuator).  Beyond the standard offering listed here we welcome other possibilities, especially in larger volume orders.

What are the possible MEMS-package combinations? Which actuator size will fit into which package?

The largest actuator die we offer has a footprint of about 7x7mm, and fits easily into the DIP-24 package. Our ~7mm die also fits into the LCC028 package, which is considerably smaller than DIP-24. We support LCC028 with ZIF-socket, MiniPCB etc.
Package choices for our 4.7x4.7mm die are either DIP-24 or LCC20. The 4.7mm die in LCC020 package is fully supported with designated MiniPCB and ZIF-sockets.
The LCC18 is the smallest package we offer. Up to 4.2x4.2mm die fit into LCC018 packages. They represent our largest production volume

How does actuator size affect the performance of MEMS mirrors?

Larger mirrors (>= 2.0mm) perform best with bigger die (pex. 4.7x4.7mm and 7x7mm). For mirror-diameters of 2.4mm and larger, the 7x7mm actuator die is recommended. However, some of our customers have opted for 4.2x4.2mm actuators with 2.4 or 3.2mm diameter mirrors, because these actuator die fit into the small LCC018 package. Those customers did not require the highest possible performance, but rather a smaller package. For smaller mirrors, smaller die perform very well.

I noticed that the development kit includes a green laser. Can the mirror also handle blue or red lasers?

The development kit includes a basic green laser pointer because green is most visible and fun to play with. Standard mirrors are aluminum (Al) coated and will work great with red, green or blue (RGB) lasers. Also, the window that covers the MEMS devices upon delivery has an antireflective (AR) broadband coating for visible wavelengths.

What types of coating do you offer on your mirrors?

We currently offer aluminum (Al) and gold (Au) coatings for our bonded mirrors, while all integrated mirrors are aluminum (Al) coated.  Other coatings are possible as long as they can be deposited with low stresses and thicknesses to maintain our mirrors’ high flatness standards.

What is the standard reflectivity of your mirrors?

It depends on angle of incidence, polarization and your preferred wavelength. Our Al coating is about 50-60nm thick. The reflectivity is very good and fairly flat in the visible wavelengths, gets better in IR (~94%), and is lowest at near-IR (at about 850nm, reflectivity is approximately at 85%). The Al coated mirrors perform well at virtually all wavelengths and are therefore our most standard offering.
Our 60nm gold coating yields great overall results for red-IR wavelengths, >98% reflectivity and ~2J damage threshold based on generally known gold-coating specs.

Can you mount a custom supplied mirror on your actuators?

It is probably not possible to bond another substrate to the actuator and get good performance. Our mirrors are very finely machined using semiconductor fabrication processes and it is perhaps the only reason that this technology is even possible. A typical mirror is only 40um thick. Yet the silicon structure and the truss-supports can give a very good flatness when a thin-film of metal is deposited (especially when deposited on both sides). Our mirrors are really very thin and typically have 50X less mass than any off-the-shelf reflectors with large inertia.

What is the laser damage threshold of your MEMS mirrors?

All devices can handle at least a few Watts of laser power. Beyond that, it will depend on specific coating, wavelength, and mirror size, because larger mirrors cool much more efficiently than smaller ones.  It is notoriously difficult to get quantitative results from laser-damage tests. Some tests of pulsed-damage point to a damage threshold of ~4J/cm^2 for our mirrors. We have not looked at the continuous/thermal damage thresholds. Some customers have used 2W 532nm laser successfully on a 2mm mirror, for example.

Have your mirrors been tested for use in challenging environments? Can they withstand vibration, extreme temperatures, humidity, etc.?

We have had tests done by an independent environmental stress testing house on multiple batches of our devices. In all cases devices were packaged in LCC018 packages and were in direct contact to a metal jig that was holding them in place and was tied to various test equipment. In each test there were 11 devices tested simultaneously. All the devices in the 0.7mm, 0.8mm, and 1.2mm diameter category passed.  Typically, the vibration and thermal shock tests do not challenge any of our designs.  We have demonstrated device operation at e.g. 200°C and well below room temperature without any notable problem.

What are the available development kit options?

Please see our Development Kits web page:
http://www.mirrorcletech.com/devkit.html
and contact us for any additional questions or details.

Does MTI offer any in-house API and DLL controller/driver platform? And if yes, what are the advantages of such a platform?

As of 2012, we have a new Controller/Driver platform for application development which does not utilize any National Instruments (NI) card or software. It was completely designed and manufactured in-house, which allowed us to build the firmware and software up from scratch, always with possible events with mind that may affect safe device operation, such as stop or start operations etc. The software development kit (SDK) that runs with this has some of the same demo executables and the same feel as our older versions. However, underneath is all fully proprietary API and DLL which is designed specifically for MEMS mirror control.
One advantage of this novel solution is that MTI owns all of the circuitry, which becomes interesting to customers who aim to integrate this driver platform into their own products. Another advantage is that this product includes laser driving control. There is a very good laser driver chip on board, giving 0-16 levels of current at MHz rates, but can be programmed in millions of levels using commands in the API. It can drive blue/green, or red lasers, but when delivered with a development kit, it will drive a red laser diode by default. Finally, this platform has a cost-advantage, with overall cost being significantly lower than our offerings that include NI hardware.

If we want to import a set of points for a laser beam to follow or a set of mirror “co-ordinates” – does your software allow that and which file format(s) are compatible with MTI's software?

We accept 3 kinds of data sets for vector graphics demonstrations:

1) Text/ASCII file with a list of keypoints
One option is to import a text file with X, Y, M (=modulation) (XYM) coordinates of keypoints. The software will then interpolate between the keypoints to fill in the time and velocities for the device such that the overall described trajectory is completed in the time of 1/(refresh_rate). The refresh rate is given by a slider in the software GUI.
The software will then repeat the described trajectory infinitely until the program is stopped. The data should be formed into three space-delineated columns as shown in the example below. The first two columns are normalized locations of keypoints from -1 to +1. These values will be scaled based on maximum voltage setting for a specific device, Vmax.
The third column is the laser modulation (M) or blanking data, 1 for ON trace and 0 for OFF trace.
An example of keypoints describing a letter "V" is:

-0.50000          1.00000           1.00000
0.00000           -1.00000          1.00000
0.50000           1.00000           1.00000
-0.50000          1.00000           0.00000

The last segment returns the trajectory to the starting point of the letter V, but with the laser off.

2) Text/ASCII file with a list of samples.
Another option is to import a text file with XYM coordinates and repeat the prescribed trajectory in the file infinitely until program is stopped. The data should be formed into three space-delineated columns as shown in the example below. The first two columns are normalized trajectories from -1 to +1. These values will be scaled based on maximum voltage setting for a specific device, Vmax.
The third column is the laser modulation (M) or blanking data, 1 for ON trace and 0 for OFF trace.
Because the file contains actual samples to be output, there will be no interpolation applied to add or reduce the number of samples.

0.51231 0.85026 1.00000
0.51163 0.85054 1.00000
0.51098 0.85083 1.00000
0.51035 0.85114 0.00000
0.50975 0.85144 0.00000

Before putting out the voltages, the program will also ask the user for the samples-per-second (SPS) rate. This rate will establish the amount of time between each row being output. So for example, SPS=1000 will have each row output at 1/SPS = 1 ms separation in time. User should be very careful to combine proper trajectories with proper SPS setting so as not to exceed mirror devices’ speed capabilities and cause ringing. A proper file of samples will end in the same location that it started such that it describes a closed trajectory and can be repeated without sudden steps or impulses to the device.

3) International Laser Display Association (ILDA) standard files:
Please refer to these sites for more information:

http://www.laserfx.com/Backstage.LaserFX.com/Standards/ILDAframes.html
http://paulbourke.net/dataformats/ilda/

Of course, for options 1 and 2 we can accept XLS or CSV files as well, or Matlab files, any easily readable tables with points in 3 columns.

Do you ship products to overseas? What are the shipping options and rates?

Yes, we ship to overseas often. Usually by FedEx (International Priority), or DHL upon customer's request. The customer is responsible for the costs of shipping and insurance. Shipping rates vary by locations, preferably charged to customer's shipping account directly if provided.

Do you accept Purchase Order?

We accept standard purchase orders subject to credit approval. For international orders we require full payment prior to shipment.

Do you accept credit card payments?

Yes, we accept all major credit cards, processing fees may apply.

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