A talk from the Developer Track at AWE Europe 2017 - the largest conference for AR+VR in Munich, Germany October 19-20, 2017
Khaled Sarayeddine (Optinvent): Optical Technologies for AR Smart Glasses
The speaker will take the audience through the various technologies that are used for AR Glasses including holographic, diffractive, and reflective light guides, light field optics, and half mirror based approaches. The speaker will analyze each technology type and will discuss the key strengths and weaknesses of each.
2. Basic Ergonomics & Photometric parameters for Near To Eye devices
AR and VR On-Eye classification & Related Optical technologies
Focus on AR Optical technologies:
Benchmarking/Advantages/Drawbacks
Future trend in optical technologies for Smart glasses
Light Field Approach
2
SUMMARY
4. Définition et introduction aux systèmes de visualisation oculaire
4
• Eye Relief ~20 to 25mm to accommodate using user’s glasses
• Eye-Box >10mm x 7mm to accommodate large population IPD
• Transparency (T>30%) or dynamic transparency
• Light Weight<100g, distributed weight over the glasses/HMD Frame
• Ophthalmic Correction mandatory
FOV Micro display
F
Perceived enlarged
Virtual image
D
Eye Pupil
Collimating
Lens
Eye Relief
Basic Ergonomics
Eye-Box
Eye-Pupil
Ophthalmic lens
5. Définition et introduction aux systèmes de visualisation oculaire
5
• Virtual image position is important for indoor use case
• Medical use case requirements: 0.5 to 2m focus distance
• Industrial use case: 2 to 4meters
• Discomfort if virtual image location is different from working distance
• Monocular situation (Right/Left Eye Rivality!):
• Discomfort if image location is located at short distance (<2 m)
• Fair and comfortable if Image location is >6m
• Flip-Vu is an elegant solution to avoid user discomfort
• Binocular situation (convergence issue):
• Discomfort on both eyes if image location is different from working distance
• Convergence issue is more annoying than focus issue
Image position & Convergence issue
Focus issue Convergence Issue
6. Définition et introduction aux systèmes de visualisation oculaire
6
Brightness:
Near to eye system works with Brigthness not with light flux!
Required Brigthness: 3 to 5kCd/m² (nits) to allow outdoor use case
• Clear daytime sky Brightness: ~10,000Nits (Cd/m²)
• Moonless Dark Sky: 10E-3 nits
High Brightness display -> More power consumption. The quality of
the display is its intrinsic Brightness efficiency: Example: 10knits/w
Light Sensor is able to adjust the Image Brightness by a factor of 2000!
The use of Photochromic lens (ORA-1) is an elegant solution
To overcome this difficulty, some Smart Glasses manufacturers are
cheating a little bit by adding a sun glasses filter to an additional visor:
• To reduce outdoor scene Brightness & increase image
contrast
Example:
Intrinsic Display Brightness of 500nits
Sun glasses filter of 10% transmission
Yields an Equivalent Brightness of ~5000nits without visor
Basic photometric
7. AR and VR On-Eye classification
& Related Optical Technologies
8. Oculus
8
VR Immersive Non See-Through Devices
Various Devices and Smart-Glasses
Fully Immersive
for VR Applications
Sony
Samsung
• Classical optics, with a low barrier to entry
• Large distortion corrected by software
• Low resolution
• Non AR capable & cumbersome
• Software making convergence & low latency for real time
video
Micro Display
Optics
Smartphone screen
Optics
FOV: 110deg
Resolution:12pixels/deg
FOV: 45deg
Resolution:~60 pixels/deg
9. 9
Non See-Through optical Devices
Various Devices and Smart-Glasses
See Around, don’t allow True AR Applications
Vuzix M100 Recon Jet
SonyTelepathy
Brothers
• Classical optics, with a low barrier to entry
• Low FOV (<14deg)
• Low resolution
• Small Eye Box
• Non AR Capable
11. 11
True AR See-Through Devices, Free air propagation Optics
Various Devices and Smart-Glasses
Laster
See-Thru
Vuzix
WRAP1200
Laster
ODG
• Cumbersome
• Low efficiency (<10%)
• Low barrier to entry for optics
• Subject to dust deposition
FOV:
30deg
Resolution:
45pixels/deg
12. 12
Google
Glass
True AR See-Through devices using Light guide technology
Various Devices and Smart-Glasses
Epson
Moverio
Lumus
Sony
OptinventHololens
Microsoft
14. Future Trends on Optical Technologies for AR Devices
14
• Light guide method will dominate
Better clearance in front of the eye
Smaller footprint and good looking
Diffractive technology still limited in FOV
Light Field feature to be integrated into Future light guide development
• Field Of View (FOV)
Informative/Industrial will be satisfied with monocular moderate FOV; 20 to 30deg
Medical will seek binocular with a moderate FOV; 30 to 40 deg
AR/Games/Video will seek larger FOV; ~50deg
Larger FOV will enable transformation of VR Market to AR; FOV > 60deg
Generally Speaking Fovation methods will help optics
• Micro-display
Lcos will dominates for the next 5 years
Oled technology for low Brightness devices (<2000nits); means indoor use case
Mems technology offer the best foot print, but still related to Laser beam quality and cost
Led based Microdisplay is the best technology for the future: Expected Brightness: >200,000nits
• Light source
White Led (for CF display) has the best ratio Efficiency/cost
RGB leds mandatory for Lcos Color Sequential suffers from Color Breakup phenomena and from limited frame frequency
rate for the Microdisplay
Laser source could be a good alternative for high end display system with very high brightness requirement
16. • General Requirements:
• High speed image generation at pixel level:
• Computing challenge for high resolution display
• Use of micro display stack
• Ability to display at least a tenth of focus planes to have realistic rendering:
• Optical system footprint and integration feasibility in question for consumer product for known development
• Optics is the key!
• Hide virtual information when displayed behind real opaque objects
Light Field
16
Focus distance
A (xi,yi,di)
Display virtual information in real time at different focus distances to fit natural rendering vision
B (xj,yj,dj)
