Gimbal-less Two Axis (Tip-Tilt) Micromirrors
Scanning two axis (tip-tilt) micromirror is an optical beam-steering (or 2D optical scanning) technology that can be used in many industries. There are several major benefits of the Mirrorcle Technologies Inc. tip-tilt mirror over competing products. Gimbal-less Two-Axis Scanning Micromirror Devices based on ARI-MEMS fabrication technology initially developed through research projects at the Adriatic Research Institute (“ARI”) in Berkeley, CA, provide ultra low-power and very fast optical beam scanning in two-axes. The devices deflect laser beams to optical scanning angles of up to 32 ° at high speeds in both axes. Compared to the large-scale galvanometer optical scanners, our devices require several orders of magnitude less driving power. Continuous full-speed operation of our electro-static actuators dissipates less than a few milliwatts of power.
MirrorcleTech devices are made entirely of single-crystal silicon, resulting in excellent repeatability and reliability. Flat, smooth mirrors are coated with a thin film with desired reflectivity. Larger mirrors can be bonded onto actuators for custom aperture sizes. Mirror sizes from 0.8mm to 3.6mm in diameter are currently available.
MirrorcleTech's MEMS micromirror technology is highly versatile and adaptable to various applications. Some devices are fabricated with somewhat generic performance specifications. Other devices are highly customized to achieve specific set of specifications, such as e.g. VGA and SVGA type projection-display.
Key Benefits
- The tilt angle is analog as opposed to on-off.
This is the key differentiation with digital micromirror elements which can not be used for arbitrary-direction optical beam steering. In other words, if a tilt angle of 7.15° is required, it is simply a matter of applying the correct voltage and that angle (or any other angle) can be obtained.
- Point-To-Point Scanning
The devices are designed and optimized for point-to-point optical beam scanning mode of operation. A steady-state analog actuation voltage results in a steady-stage analog angle of rotation of the micromirror. There is a one-to-one correspondence of voltages and angles that is highly repeatable.
- Modular Design
In order to produce devices with a different mirror size, most technologies require not only a new fabrication cycle, but in some cases complete actuator redesign. At Mirrorcle Technologies we provide for the first time a MEMS based, customizable aperture size beam steering technology. Namely, sets of electrostatic actuators optimized for speed, angle, area footprint or resonant driving are designed and realized in a self-aligned silicon fabrication process. Metallized, ultra low-inertia single crystal mirrors made stiff and flat by a special design of silicon beams are created in a separate fabrication process. The diameter, as well as geometry of the mirror is selected by customer, in order to optimize the trade-offs between speed, beam size, and scan angle for each individual application. The mirrors are subsequently bonded to the actuators.
A variety of gibmal-less two-axis actuator designs are available. The actuators lend themselves inherently to a modular design approach. Each actuator can utilize rotators of arbitrary length, arbitrarily stiff linkages, and arbitrarily positioned mechanical rotation transformers. Some devices are designed to operate at low voltages (>8° of mechanical tilt at 100V,) exhibit the largest maximum scan angle and occupy a small die size (3mm x 3mm.) Another series of devices operate at higher voltages and occupy a slightly larger die size (4.2mm x 4.2mm.) In return, they provide higher scanning speeds. Finally, there are devices that require the highest driving voltages and occupy the largest die size (~6mm x ~6mm,) in order to provide the fastest scanning speeds, especially for larger mirrors.
- High Speed Point-To-Point Optical Beam Scanning
The major advantage of our proprietary gimbal-less design is the capability to scan optical beams at equally high speeds in both axes. A typical device with a 0.8 mm diameter-sized micromirror achieves angular beam scanning of up to 500 rad/s and has first resonant frequency in both axes above 4 kHz. Large angle step response settling times of <100 µs have been demonstrated on devices with micromirrors up to 0.8 mm in diameter. Devices with 2.0mm diameter mirrors can achieve large angle step settling times of <2ms.
- Dynamic Mode Scanning
Devices can also operate in the dynamic, resonant mode. In this mode, low actuation voltages at frequencies near resonance result in large bi-directional optical beam angles (e.g. -16° to 16°). Resonant frequencies are in the range from several kHz up to 21 kHz and higher for MEMS display applications. Resonance depends on the actuator type (series,) and the micromirror type and diameter that is assembled with the actuator.
Summary of Specifications
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1-Quadrant Devices:
- Standard / Integrated Mirror Size: 0.8 mm and 1.2mm diameter
- Bonded Mirror Sizes: 0.8, 1.0, 1.2, 1.6, 2.0, 2.4, 3.2, and 3.6 mm diameter
- Maximum tilt angle under point-to-point driving: 0 ° to >8° mechanical each axis
- Maximum tilt angle under resonant driving: -10° to +10° mechanical
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4-Quadrant Devices:
- Standard / Integrated Mirror Size: 0.8 mm diameter
- Bonded Mirror Sizes: 0.8, 1.0, 1.2, 1.6, 2.0, 2.4, 3.2, and 3.6 mm diameter
- Maximum tilt angle under point-to-point driving: -6° to +6° mechanical on each axis
- Maximum tilt angle under resonant driving: -10° to +10° mechanical
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Common Specifications for All Devices:
- Surface Roughness: <20 nm rms
- Drive voltage: 0 -140 Volts
- Mirror Radius of Curvature: >5 m
- Positional repeatability: better than 0.00005° (50 micro-degrees)
- Temperature operation: -40°C to 125°C (200°C demonstrated for integrated mirrors)
- Optical power handling: depends on mirror size and wavelength, 1W demonstrated on a 2mm mirror
- First resonant rotation frequency: >3 kHz for both axes for small mirror sizes
MirrorcleTech devices are highly customizable with several controllable trade-offs (mirror size vs. speed, angle vs. speed, die size vs. speed, die size vs. cost, etc.) Custom designs and fabrication is performed for larger orders.
Detailed Datasheet Downloads
Pricing
Click here (pdf) for prices of our off-the-shelf demonstration devices available in small quantities .
Please contact us for additional product details, custom device specifications, and large-quanity quotations.
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