Optotune ELM-F Series Liquid Lens-Based Fixed-Focal-Length Imaging Modules

Overview

The Optotune ELM-F Series represents a class of purpose-engineered fixed-focal-length imaging modules built around Optotune’s electrically tunable liquid lenses. Unlike conventional mechanically actuated autofocus systems, the ELM-F architecture embeds a high-speed, low-hysteresis liquid lens element within a precisely aligned, monolithic optical housing—enabling sub-millisecond focus adjustment without moving parts or mechanical backlash. This design leverages electrowetting-based focal tuning, where applied voltage modulates the curvature of an immiscible liquid interface to dynamically shift the effective focal power (±10 to ±100 dpt typical range depending on model). The modules are optimized for integration into embedded vision systems requiring rapid, repeatable focus transitions under real-time control—particularly where space constraints, shock resistance, and long-term reliability preclude traditional voice-coil or stepper-driven solutions.

Key Features

• Sub-10 ms focus response time across full tuning range, enabling frame-synchronized depth scanning in high-speed imaging applications
• Vignetting-free optical path with low f-number performance (f/1.4–f/2.8 depending on focal length variant), maintaining uniform illumination across 4/3″ image sensors
• Hermetically sealed, solid-state optical assembly with no lubricants or wear-prone components—rated for >10 million actuation cycles
• Integrated driver interface supporting analog voltage (0–5 V or 0–10 V) and digital I²C command protocols for OEM system integration
• Thermally stable lens housing with coefficient of thermal expansion matched to fused silica and BK7 elements to minimize focus drift over –10 °C to +60 °C ambient range
• Modular mechanical design compliant with both S-mount (M12 × 0.5) and C-mount (17.526 mm flange distance) standards

Sample Compatibility & Compliance

The ELM-F series is validated for use with global-shutter CMOS sensors up to 4/3″ format (diagonal ≈ 21.6 mm), including Sony IMX series, ON Semiconductor PYTHON, and e2v EV76 devices. Optical performance meets ISO 10110-5 surface quality specifications (scratch-dig 60-40) and ISO 9022 environmental testing requirements for vibration (IEC 60068-2-6) and thermal shock (IEC 60068-2-14). All modules are RoHS 2015/863/EU compliant and manufactured under ISO 9001-certified processes at Optotune’s facility in Zurich, Switzerland. No FDA clearance or CE marking is required as these are non-medical, non-laser-emitting optical components; however, they are routinely deployed in Class I medical imaging subsystems and automotive ADAS validation rigs meeting ISO 26262 ASIL-B functional safety guidelines.

Software & Data Management

ELM-F modules do not include embedded firmware or onboard storage. Instead, they operate as deterministic electro-optical transducers controlled via external host systems. Auniontech provides open-source Python and C++ SDKs—including LabVIEW VIs and HAL abstraction layers—for seamless integration with National Instruments, Basler pylon, and FLIR Spinnaker platforms. All calibration data (voltage-to-focus maps, MTF curves at multiple working distances, distortion coefficients) are delivered in standardized JSON and Zemax .ZBF formats. For regulated environments, optional audit-trail logging and configuration versioning can be implemented at the system level in accordance with FDA 21 CFR Part 11 requirements when paired with validated host software.

Applications

• High-throughput barcode and 2D code readers in logistics automation, where dynamic depth-of-field adjustment compensates for variable item height on conveyor lines
• Autonomous drone vision systems performing real-time terrain-following and obstacle avoidance using multi-plane focus stacking
• Iris recognition terminals requiring consistent focus across subject distances from 25 cm to 1 m without mechanical latency
• Smart packaging inspection stations verifying seal integrity, fill level, and label placement across heterogeneous product geometries
• Mobile retail robots performing shelf-monitoring tasks under varying lighting and object spacing conditions
• Industrial metrology setups combining structured light projection with adaptive focus for measuring curved or textured surfaces

FAQ

What is the maximum operating temperature for continuous use?
Continuous operation is rated from –10 °C to +60 °C ambient, with derating recommended above 50 °C for extended lifetime (>5 years MTBF).
Can ELM-F modules be used with telecentric illumination?
Yes—models with focal lengths ≥50 mm support telecentric alignment when paired with compatible relay optics; detailed chief ray angle (CRA) data is provided in the optical datasheet.
Is optical distortion corrected in firmware?
No—distortion is optically minimized during design; residual geometric distortion (typically <0.5% TV distortion at center field) must be corrected in downstream image processing using supplied polynomial coefficients.
Do these modules support autofocus algorithms?
They do not include closed-loop autofocus logic; however, their fast open-loop response enables integration with external contrast- or phase-detection AF engines running on FPGA or embedded GPU platforms.
Are custom focal lengths or mounts available?
Yes—Optotune offers engineering collaboration for application-specific variants, including custom flange distances, extended spectral transmission (UV-VIS-NIR), and hermetic sealing for cleanroom deployment.