Fast focusing with electrically focus-tunable lenses

Transcription

1 Fast focusing with electrically focus-tunable lenses November 2015 Mark Ventura, Vice President Sales & Marketing Bernstrasse 388 CH-8953 Dietikon Switzerland Phone

2 Agenda Introduction Focus-tunable lens technology Application examples - Machine Vision - Microscopy Electrical integration & software Available products 1

3 Our innovation: A focus-tunable lens Engineer s solution Nature s solution Optotune s solution Optotune has successfully copied the human eye

4 Tunable lenses solve a common imaging problem Fixed focus optics Image sensor Optotune approach Image sensor Lens with fixed focal length Working range limited by depth of field Larger lens with variable focal length Increased working range 5cm to infinity Benefits Larger working distance range Faster recognition Less lighting required thanks to smaller F# Easier installation 3

5 Company overview Electro-optical component provider Founded 2008 >50 employees Sales partners in 27 countries HQ located in Zurich, Switzerland Privately owned 4

6 Agenda Introduction Focus-tunable lens technology Application examples - Machine Vision - Microscopy Electrical integration & software Available products 5

7 Working principle based on membrane and fluid Mechanically tunable lens Electrically tunable lens Membrane Lens shaper Fluid Videos available on 6

8 Response time of ~10ms 600 Hz focus oscillation for fast image stacking 7

9 Transmission [%] Membrane & fluid is transparent >90% from nm 100 Lens schematic Lenses with LD material Lenses with HR material Wavelength [nm] 8

10 Agenda Introduction Focus-tunable lens technology Application examples - Machine Vision - Microscopy Electrical integration & software Available products 10

11 Three main configurations for machine vision Front-lens configuration Back-lens configuration High magnification Camera Fixed focal length lens Optotune lens Camera Optotune lens Fixed focal length lens >=35mm Camera Tube lens Optotune lens Zoom lens Working distances from infinity to 100mm Thread adapter required if filter thread not an M25.5 Tunable lens acts like a distance ring Easy mechanical solution - C-mount threads on both sides of Optotune s lens Works best with infinity corrected lenses 1x to 40x Magnification Most versatile configuration Best quality for short working distances Best for high magnifications 11

12 Front-lens configuration typically for large working distances Front-lens configuration C-mount camera C- to S-Mount adapter 12mm board lens EL C-VIS-LD-MV C-mount camera Fixed focal length lens 3 cm EL C-VIS-LD-MV 6.5 cm Working distance ranges from infinity to about 150mm 12 Working distance 47 cm

13 Back-lens configuration typically for macro imaging Back-lens configuration 20mm C-mount camera ½ 5MP sensor Optotune lens EL Ci-VIS-LD-MV Results: Configuration Large WD Short WD Magnification 0.4x 0.7x Working distance 160mm 100mm Z range 25mm 5mm Z resolution 6.25µm 1.25µm HFOV 16mm 9mm Tamron 50mm lens (23FM50SP) This only works for lenses with focal length > 30mm 13

14 EL between high-mag & tube lens High mag Results: C-mount camera ½ 5MP sensor 1.5x mini tube lens P/N Magnification 1.1x 3.5x 7.9x Z range 400mm 40mm 8mm Z resolution 100µm 10µm 2µm DOF (approx.) 1mm 0.3mm 0.1mm HFOV 4.5mm 1.4mm 0.65mm Optotune lens EL Ci-VIS-LD-MV Optem 70XL zoom (0.75x-5.25x) P/N Coaxial lighting unit with lens P/N LED ring light (used instead) Working distance: ~90mm No vignetting C-mount threads fit perfectly All components available off the shelf Optem is a registered trademark of Qioptiq, Inc 14

15 Low cost AF microscope with fixed mag High mag C-mount camera Magnification: ~5X Z-range: ~3mm Empty C-mount tube, ~50mm long Optotune lens EL Ci-VIS-LD M22 to C-mount adapter 25mm lens (reversed!) Edmund Optics Working distance: ~20mm 15

16 Front lens Back lens What we need to make a recommendation Customer requirement Calculations Overall focal length: Recommendation From MV appl. note: Optical leverage of EL: 1. Field of view (FOV) on object 2. Minimum and maximum working distance (WD) 3. Z-range on object (distance to focus over) 4. Target sensor size Optotune EL selection Estimate of required current range Thread adapters 16

17 New online lens configurator Visit configurator.optotune.com 17

18 Neurocheck: EL Ci on inspection robot Refocusing allows for optical zoom with inspection robot Front lens configuration with 12mm S-mount lens Driver integrated in machine vision software Neurocheck 18

19 Sanxo scope: Inspection at high resolution Inspection station with 10MP camera EL Ci in front lens configuration with 25mm lens Driver integrated in machine vision software Modular X Features: - Click to autofocus - Focal sweep with 3D rendering 19

20 Qioptiq has integrated the EL TC in Optem Fusion microscope Zoom remains parfocal as the EL is placed BELOW the zoom 20

21 Where are the limits? Limited aperture size Wavefront error influenced by gravity Tunable lens aperture currently limited to 16mm Optical axis vertical: λ RMS Optical axis horizontal: λ RMS Larges possible image circle is currently 30mm Wide angles lenses (<8mm) are problematic Try to set optical axis vertical (e.g. by using a mirror) Note: Wavefront error measured at 525nm over 80% of clear aperture 21

22 Agenda Introduction Focus-tunable lens technology Application examples - Machine Vision - Microscopy Electrical integration & software Available products 22

23 Focusing is particularly important in microscopy Most microscopes take 2D images But life is 3-dimensional DOF is especially small at high magnification 23

24 Examples Wide-field microscopy Confocal microscopy Two-photon microscopy Light-sheet microscopy 24

25 Agenda Introduction Focus-tunable lens technology Application examples - Machine Vision - Microscopy Electrical integration & software Available products 25

26 The focal power (D = 1/f ) of Optotune s lenses is controlled by current MV LP Note: This curve varies from lens to lens. However, it is reproducible once calibrated 26

27 Three options to drive Optotune s lenses Optotune Lens Driver Our circuit on customer PCB Customer s own circuit Currently only USB based RS232 & analog interface possible for R&D (connections on PCB) Responsibility for performance with Optotune FW shared in compiled form only All interfaces can be used Responsibility for performance with Optotune Only very limited FW support provided Implementation of focal power mode is not simple Responsibility for performance with customer! Best for R&D and low volume Fast implementation for high volumes Optimized for cost & performance 27

28 How to find the right focus Image based autofocus Preset lookup tables Using a distance sensor Product Focus Distance Focus A 2 dpt 100mm 1 dpt B 1 dpt 200mm 2 dpt C 3 dpt 300mm 3 dpt A B C A B C Multiple images are acquired to find the best focus by algorithm Typically frames required ~1sec focus time Focus positions are stored in a lookup table during calibration (teaching) Only one focus step required 15ms focus time Multiple distance vs focal power points are saved during calibration Only one focus step required 15ms focus time Cheap, flexible but not 100% reliable Inflexible, as reliable as the focal power mode (~0.1dpt) Flexible, quite reliable but expensive 28

29 Serial protocol can be implemented by customers Optotune s Lens driver is a serial device - COM port in Windows - /dev/ttyacm0 in Linux Command flow: Example commands are: - Start Ready (works in ASCII) - SetCurrent - SetFocalPower - GetTemperature Serial protocol: Optotune provides sample code in C#, Labview, Python and Halcon 29

30 Increasing number of software partners 30

31 Agenda Introduction Focus-tunable lens technology Application examples - Machine Vision - Microscopy Electrical integration & software Available products 31

32 Optotune s electrically focus tunable lenses EL-6-18 EL EL C(i) EL Focal power range* Dpt 8 22 Dpt Dpt Dpt Dpt Dpt Clear aperture 6mm 10mm 10mm 16mm Outer diameter 18mm 30mm 30mm 40mm Wavefront quality Absolute focal power accuracy <0.1 / 0.15 <0.25 / 0.5 <0.15 / 0.25 <0.25 / 0.5 <0.25 / 1.5 (<0.1 dpt) *** <0.15 dpt < 0.1 dpt TBD Built-in sensors Applications Temperature Motor position Machine vision OCT None Temperature Temp./Optical feedback Microscopy Machine vision Machine vision Ophthalmology 32 * Depends on selected optical fluid ** vertical / horizontal optical axis ***Qualification is ongoing

33 EL configurations for machine vision Front-lens configuration Back-lens configuration C-mount camera C-mount camera M42-mount camera C-mount lens filter threads M25.5 M27 & M30.5 EL TC-VIS-5D-C EL TC-VIS-5D-M42 EL TC-VIS-5D-M25.5 EL TC-VIS-5D-M27 EL TC-VIS-5D-M30.5 C-mount lenses telecentic or FL>30mm M42-mount lens Typical WD range: 200mm to infinity WD <200mm, Range depends on magnification 300mm to infinity 33

34 Optotune 1 slide Optotune Switzerland AG Bernstrasse 388 CH-8953 Dietikon Switzerland Phone: Fax: info@optotune.com

35 No loss in quality with 12mm board lens Front-lens configuration 12mm lens only 12mm lens + EL C ½ sensor C-mount camera C- to S-Mount adapter 12mm board lens ½ sensor C-mount camera C- to S-Mount adapter 12mm board lens Tunable lens EL C 35

36 Up to 20m of combined cable length tested USB 2.0 cable Hirose cable 1.8m included - Ships with Lens Driver 4 5m specified - According to USB 2.0 standard 10m tested - Full performance verified 1m Optotune standard - P/N: CAB m specified - According to I2C standard 10m tested - Full performance verified - I2C enters clock stretching mode 36

37 Focal power mode for good reproducibility Why it is important: - The focal power of our lenses drifts with temperature by about 0.06 diopters / C (depends on lens model) Lens characterization f vs T vs I Typical accuracy achieved: +/- 0.1dpt I need a lens with f=125mm (8 diopters) Use focal power mode to set lens to 8 diopters Temperature compensated control current to adjust lens to 8 diopters Lens calibration curve stored on lens internal memory Lens calibration table and temperature read by lens driver Temp sensor with EEPROM f=125mm (8 diopters) 37