A talk from the Develop Track at AWE USA 2018 - the World's #1 XR Conference & Expo in Santa Clara, California May 30- June 1, 2018. Khaled Sarayeddine (Optinvent): Optical Technologies & Challenges for Next Generation AR The talk will describe the current status on key optical technologies and ongoing development to meet Small footprint & Large FOV High resolution Display, as well to accommodate Light field feature. http://AugmentedWorldExpo.com

1. AWE 2018
May 30
th
Santa Clara
Optical Technologies and Challenges for
Next generation AR
Khaled Sarayeddine
CTO & Co-Founder
Optinvent
www.optinvent.com

2.  Basic Ergonomics & Photometric parameters for Near To Eye devices
 AR Related Optical technologies
 Benchmarking/Advantages/Drawbacks
 Future trend in optical technologies for AR
 Light Field Approach
2
SUMMARY

3. 3
• Eye Relief ~20 to 25mm to accommodate user’s glasses
• Eye-Box >10mmH x 7mmV without vignetting to accommodate large population IPD and
visual comfort
• Transparency (T>30%) or dynamic transparency
• Light Weight<30g
• Ophthalmic Correction mandatory
FOV Micro display
F
Perceived enlarged
Virtual image
D
Eye Pupil
Collimating
Lens
Eye Relief
Display Module Basic Ergonomics
Eye-Box
Eye-Pupil
Ophthalmic lens

4. 4
Brightness Dynamics:
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. Brightness efficiency:
 Example: >10knits/w
• Light Sensor to adjust the Image Brightness
• Photochromic lens is an elegant solution
• Add Neutral filter, Example:
 Target Image Contrast vs Outdoor scene: 2
 Display Brightness of 700nits
 Neutral filter of 20% transmission
 Equivalent Brightness of ~5000nits without visor
Display Module Basic photometrics
2<𝟏 +
𝑳 𝑫𝒊𝒔𝒑𝒍𝒂𝒚
𝑳 𝑶𝒖𝒕𝒅𝒐𝒐𝒓 ∗𝑻 𝑭𝒊𝒍𝒕𝒆𝒓 ∗𝑻 𝑺𝒆𝒆𝒕𝒉𝒓𝒐𝒖𝒈𝒉

5. 5
• Virtual image position is important for indoor use case
• Medical use case requirement: 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
• Vergence-Accomodation issue will be solved with Light field approach
Vergence-Accomodation Issue
Focus issue Convergence Issue

6. 6
Safety Requirement:
• For any HMD device, the Light Guide should be conform to current Ophthalmic
lens regulation:
 USA FDA Regulation 21 CFR 801.410 (Drop Ball/Impact Test)
 Monolithic plastic Light guide is the best approach
Display Cost & Scalability:
• Low Cost for large volume
• No Complexity in Assembly
• High Manufacturing Yield
• Scalability in production
Regulation, Cost & Scalability

7. 7
Free air propagation Optics: The residue of old classical optics
• Cumbersome & Form factor issue
• Low efficiency (<10%)
• Low barrier to entry for optics
• Subject to dust deposition & cleaning
ODG

8. 8
Google
Current Light guide technologies
Epson
Lumus
Hololens
Microsoft
Optinvent
Digilens
& Sony

9. 9
Clear-Vu technology: The only to use Mold plastic light guide
Display Module
by Optinvent
All Optical Parts are in Plastic
Micro Display
& Illumination
Collimator Monolithic molded
light guide
No holograms, diffractive
elements, or polarizers!
Performances:
FOV 23 deg & 26deg
Weight 16g
Display Resolution: 42 pixels/Deg
Brightness: 3000nits
See-through Transparency: 50%

10. 10
New Approach: Nano-Structured Light guide (Combiner)
Idea: Use the property of resonance of embedded nano-
structure to diffract selective wavelength at specific angle
to extract image rays toward the eye-pupil and to
transmit surrounding rays toward the eye without
modification.
• Work still in R&D stage
• Can generate large FOV
• Difficulty to get large eye-box
• Still use three “light guides”, one for each R,G& B color
Courtesy of
Resonant Screens

11. • General Requirements:
• High speed image generation at pixel level:
• Computing challenge for high resolution display with additional depth information
• Use of several display stack & time sampling to separate different focus information
• Ability to display at least >4 focus planes to have realistic rendering:
• Optical system footprint and full computing platform integration feasibility in question for
consumer product!
• Hide virtual information when displayed behind real opaque objects
• Principal Challenge:
• Make a minimum viable wearable product with small foot print and affordable cost!
Light Field
11
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)
Human Eye

12. Future Trends on Optical Technologies for AR Devices
12
• 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
 Resonant Nano-structure Light guide is new & still need to be validated for RGB wide FOV systems
• 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 & Eye tracking 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, cost safety regulation issue
 Led based Microdisplay is the best technology for the future: Expected Brightness: >200,000nits
• Light source
 White Led (for CF display) has today 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

13. THANK YOU!
Khaled Sarayeddine
khaled.sarayeddine@optinvent.com