Frequently Asked Questions

About MirrorcleTech

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, free-space communication, position-tracking and sensing, rapid prototyping, Light Detection And Ranging (LADAR / LIDAR), Dynamic Solid State Lighting and Dynamic Headlights, and various biomedical imaging applications such as optical coherence tomography (OCT)-based imaging, among many others.

What makes Mirrorcle Technologies' mirrors unique and better?

Mirrorcle Technologies offers proprietary gimbal-less two-axis MEMS designs which allow faster beam steering for larger mirrors and large angles.  This results in the overall figure of merit in performance (Speed * Angle * Diameter) that is generally an order of magnitude larger than any competing approaches.  Moreover, Mirrorcle’s MEMS are manufactured in a proprietary process which allows the entire microelectromechanical structure to be manufactured in a single (monolithic) layer of single-crystal silicon. This results in the highest repeatability and reliability of mirror positioning over many years and/or billions of cycles – and over an extremely large temperature range.  Namely, this kind of manufacturing does not include any troublesome materials in moving parts such as metals, polymers, polysilicon, piezo-materials, magnets.  All the moving, flexing portions of the structure are made of purely elastic material (single-crystal silicon), and they work entirely with electrostatic actuation with no notable current. These 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.
Additional information available in the MEMS Mirror Technical Overview.

MEMS Mirror Customizability

What are the available mirror sizes?

We currently offer circular mirrors ranging from 0.8 to 7.5mm in diameter as regular in-stock items.  Additionally, we have offered long, rectangular or elliptical 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 ~40-50um thick. Only smaller mirrors are integrated, usually those that have e.g. 0.8mm, 1.2mm, 2.0mm and 2.4mm diameter.

Bonded mirror:  A bonded mirror is fabricated separately from the MEMS device/actuator and it is also 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 or e.g. rectangular and elliptical mirror structures.

Does Mirrorcle Technologies offer resonant-only MEMS mirrors?

Yes, we have multiple designs available that are used in laser projection (e.g. picoprojector or retinal display) applications to display video and images, and are also used in imaging applications such as fast-scanning Lidar. It is usually best to discuss such less standard requirements with us directly as there are several options to choose from – but a few examples are given here: A single-axis device A9R8 with a 0.8mm mirror has ~24kHz resonance and is specified for at least +/-8° of mechanical scanning (+/-16° optical).  Another mirror, A9R12 has a 1.2mm diameter and resonates around 13kHz.  A 1mm diameter mirror design A1R10 has ~16kHz resonance.

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 8.0mm x 8.0mm, and fits easily into either a DIP24 package or into our TINY48 connectorized package solution. Package choice for our smaller die is the TINY20, a more compact solution which can house chip sizes up to 5.2mm x 5.2mm footprint.

What types of coating do you offer on your mirrors?

We currently offer aluminum (Al) as the standard mirror coating on all products, and gold (Au) for certain customers and applications where the benefits outweigh the additional cost.

Can you mount a custom supplied mirror on your actuators?

It is 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.

MEMS Mirror Capabilities

Can Mirrorcle Technologies mirrors be used for point-to-point (or quasistatic) steering?

Yes. In fact, Mirrorcle’s 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.  This is also frequently called quasistatic beam steering.  Users can essentially program position and velocity (scan rate) of either axis arbitrarily from dc (steady position) to a maximum speed value which depends on the specific product. 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.)

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. Detailed mechanical models are provided to current customers to aid in their optical design.
Bonded mirrors include pedestals or stand-offs which raise the reflective surface of the device by a few hundred microns.  The pivot point of bonded mirror would therefore lie a few hundred microns below its reflecting surface.

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

Most of our devices are specified and delivered exceeding +/-5° mechanical tilt on both axes (-10° to +10° optical scan – so a total optical field of regard of ~20°). Some designs are specified for +/-6°, and finally there are designs for +/-8° (32° FoR).  Generally the angle is limited due to trade-off with speed, although in some cases with bonded mirrors the limitation is mechanical, to avoid contact of the mirror plate with the underlying actuator. It is practically always possible to trade off speed for additional angle, and vice versa.

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 useable bandwidth of ~7kHz, with its resonant frequency at ~6kHz.  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.

How does actuator size affect the performance of MEMS mirrors?

Larger mirrors (>= 2.0mm) perform best with bigger die (e.g. 5.2mm x 5.2mm up to 8.0mm x 8.0mm). Larger actuators offer more torque and generally more speed when combined with a give mirror size. Within a size category of actuators, we offer different designs, some offer more angle (and less speed), some offer less angle (but more speed) when combined with a given mirror size.

I noticed that the development kit includes a red laser. Can the mirror also handle lasers of other visible and Infrared (IR) wavelengths?

The development kit includes a 5 mW (Class IIIa) Red (635 nm) Laser with a small ~1.5mm diameter beam which works well with most of our mirror sizes. They come with 1-bit digital modulation capability for fast on/off control. Great for experimentation with various vector graphics capabilities of our devices and software, and for development of synchronized digital outputs and/or triggers that are available with the Mirrorcle’s USB Controller. Standard mirrors are aluminum (Al) coated and will work great with red, green, blue or IR lasers – the mirror coating has a very broadband reflectance.  Gold-coated mirrors are also offered for improved reflectance in certain wavelengths such as e.g. 700-1000nm range. We offer three different window types that cover the MEMS devices with antireflective (AR) broadband coating for VIS, NIR and IR wavelength ranges.

What is the standard reflectivity of your mirrors?

It depends on the choice of coating (Al or Au), angle of incidence, polarization and your preferred wavelength. The Al coated mirrors perform well at virtually all wavelengths and are therefore our most standard offering – for details one can look up any standard reflectance curves for ultra-smooth aluminum as a reference.  Our gold coating yields great overall results for red to IR wavelengths, and can also be compared to any standard ultra-smooth thin film gold coating.

What is the laser damage threshold of your MEMS mirrors?

All the MEMS mirrors can handle up to 2W of continuous optical power (CW) at practically any wavelength, polarization, etc. Above 2W the threshold for damage of course depends on the mirror size, coating, and wavelength. For example, 3W CW blue or green on a 2mm or larger mirror.  Larger mirrors would have a higher threshold as they cool much more efficiently than smaller ones. A Mirrorcle paper regarding use of MEMS mirrors for automotive headlights presented the damage threshold of the 2mm mirror to be ~4W at 445nm wavelength. Regarding fluence damage thresholds for very high peak power pulses (with low CW or average power), it is necessary to test for each and every specific case – however for reference one can look at aluminum or gold coating damage thresholds in general.

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 in direct contact to a metal jig that was holding them in place and was tied to various test equipment. All the devices in the integrated category passed 500G shock tests. Typically, the vibration do not challenge our smaller mirror designs – with increasing mirror size (and decreasing resonant frequency), shock or vibration could result in unpredictable device behavior.  As for temperature tolerance, the MEMS mirrors easily pass any requirements of thermal shock, and are specified from -40°C to 105°C.  In development projects, we have demonstrated reliable device operation from -270°C to +200°C and well below room temperature.  Again all of these aspects of robustness are owed to the single-crystal silicon structure and electrostatic driving.

Development Kits

Why are the “TINY20” and “TINY48” the standard packages that comes with development kits?

The TINYxx package is an assembly of a small printed circuit board (PCB) with four mounting holes, a small 10-pin connector (on its backside), and a leadless ceramic carrier LCC20 or LCC48 (on its frontside).  We also call these “Connectorized Packages” because they are basically plug-and-play solutions for customers.  The MEMS mirrors are assembled in the LCCs and are covered with antireflection (AR) coated glass windows for protection and are positioned in the geometric center of the LCC and overall TINY package.  The backside connector mates with a small 10-pin ribbon cable which is provided with all Mirrorcle MEMS Controllers and MEMS Drivers. This solution is great for any level of integration – from initial experiments to production.  It allows for easy and safe manual handling without tools, allows for reliable mounting in optical cells, provides good protection for the MEMS device, etc. It can easily be mounted onto a designated mount which is easily integrated into standard optical breadboarding and comes with a flexible fine-tuning solution to allow alignment. Quick switching of device types is thus possible in a convenient and safe manner.

What are the available development kit options?

Please see our Development Kits web page here 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 a Controller/Driver platform with the USB-SL MZ MEMS Controller for application development, we completely design and manufacture in-house. This 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 MEMS Controller has some of the same demo executables and the same feel as our older versions, and includes additional functionality and options. Underneath is a fully proprietary API and DLL which is designed specifically for MEMS mirror control.
One advantage of this 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 that can be synchronized with mirror movement. There is a very good laser driver circuit on board, giving 1-bit digital modulation at ~100kHz rates. The controller has a correlated digital output port has an 8-bit output that can be programmed in 255 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 module by default.

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/

Options 1 and 2 can accept .kpt and .smp file formats respectively, or .txt files for both, containing easily readable tables with points in 3 columns.

Ordering

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

Yes, we ship to overseas often, usually via FedEx (International Priority). The customer is responsible for the costs of shipping and insurance. International customers are also responsible for any applicable customs duties and related fees. Shipping rates vary by location, based on FedEx’s estimated costs, preferably charged to customer’s FedEx account directly if provided. Additional handling and document fees may be assessed for certain ship to countries which require a COO form, or shipping method different from our standard procedures.

Do you accept Purchase Order?

We accept standard purchase orders and offer Net 15 or Net 30 payment terms to qualified accounts upon credit approval. Depending on the order or contract agreement, we may still require 50% prepayment on NRE and some larger orders. For new customers and/or international orders, we generally require full payment prior to shipment. We accept company checks and bank transfer for domestic orders, and wire transfer for international orders.

Do you accept credit card payments?

Although we prefer payments in company checks and bank transfer, we accept all major credit cards; with an additional 3.5% processing fee applying to domestic credit cards and a 4% processing fees applying to international credit cards. These fees are generally not included in the quotation prices (unless requested by the customer) but will be added when processing the credit card transaction. The amount charged will be listed in the invoice.