A talk from the XR Enablement Track at AWE USA 2019 - the World's #1 XR Conference & Expo in Santa Clara, California May 29-31, 2019. Soon gi Park (LetinAR): PinMR: Novel Optical Solution for AR Glasses LetinAR is a Seoul-based startup developing see-through optical systems for wearable augmented reality devices. Based on our unique pin mirror technology which has quite different approaches from any other existing combiner optics, LetinAR has demonstrated ultrawide field-of-view more than 80 degrees with 8K high resolution. LetinAR also presented a form-factor-oriented glasses prototype device having the same appearance of normal glasses. In this presentation, we introduce a pin mirror technology and its benefits and contributions to wearable AR hardware including high image quality without any degradation, visual comfort supporting correct vergence and accommodation, wide field-of-view providing immersive experience as well as cost effective manufacturing process. We believe that the advantages of the pin mirror technology will not only suffice the optical requirements in future AR devices, but also shorten the beginning of AR/VR/MR era. https://awexr.com

1. Pin MR:
Novel Optical Solution forAR Glasses
Soon-gi Park, Ph. D.
Principal Research Scientist
AWE 2019

2. Introduction
Pin Mirror technology
Manufacturing
Cost comparison
Milestone
Contents

3. LetinAR Inc. Is established Horizontal expansion of PinMRTM
Seed funding from &
Reducing of distortion using
aspheric surface PinMRTM
design
Plastic PinMRTM
lens development
by ultra- Precision diamond cutting
Plastic aspheric surface
PinMRTM
lens
Development by injection
molding technology
Development of prototype
PinMRTM AR glasses
Design of expanded FOV lens
vertically
Introduction PinMRTM AR glasses at
CES / MWC 2018
Series A funding
from , .
& 3 VC’s
Introduction PinMRTM AR lens
for 4K wide FOV and Small
Form Factor smart glasses
at CES/MWC 2019
Series A funding from KB Investment
5 Patents registered in Korea /
9 Patents are filed in Korea /
11 Patents are filed globally
Development history of LetinAR PinMRTM lens
10 3
6
7
8
10
11
12
1
7
12
1
2
2016 2017 2018 2019

4. FOVImage quality Focus Form Factor
There are many requirements and issues for popularization of AR glasses.
Normal vision
Issues for the Optics

5. The bending of light based on wavelength &
The image light bounce many times across the waveguide
Color uniformity
white color breaking into red, green, and blue
Degrading of color uniformity in conventional AR
glasses
Diffraction efficiency according the angle for
RGB wavelengths
(Jolly et al., Proc. SPIE 10127)
Degrading of color uniformity in conventional lens

6. https://www.youtube.com/watch?v=oEUZRGjttow

7. Vergence-Accommodation Conflict in conventional optic solution
the LetinAR PinMR™ lens has clear viewing zone between 25cm,
and theoretically, an infinite distance away
Wide viewing zone (DOF, Depth of Field)
à Virtual image can be focused on at any time and multi focal
plane can be supported

8. https://www.youtube.com/watch?v=Z121SvGI50w
https://www.youtube.com/watch?v=S3dtttINlkQ
https://www.youtube.com/watch?v=ZKcM6qCPvDU

9. One PinMR provides 12 - 15o of FOV.
FOV can be simply expanded with additional PinMR.
LetinAR PinMR lens supports more than 80o.
Glasses type ~ 30o Goggle type ~ 80o
Wide FOV

10. https://www.youtube.com/watch?v=d81yQtONMn8

11. HoloLens 2
HoloLens
MagicLeap One
Lumus OE Vision
WaveOptics Phlox (DMD)
WaveOptics Phlox (LCoS) Vuzix Blade
DigiLens
Form-factor

12. Micro display
Lens substrate
Pin MRTM
Simple structure and small form-factor
Small-form factor
Glasses
High performance
Goggle
Lens substrate
Micro display module
Pin MRTM

13. Normal transparency 90%
Optic efficiency = Typically more than 10%
No tunneling view effect
Tunneling view
Unobstructed view
View through
PinMR combiner
Flares
Normal vision

14. Light efficiency
Source: Cnet
Source: TechCrunch
Source: Engadget
HOE/DOE
Aluminum mirror
Source: Mobilegeeks.de
YouTube channel

15. Raw materials
Optical glass
Optical plastic
Glass Plastic
Optical quality Very good Moderate to good
Price moderate good
Hardness good moderate
Weight moderate good
Durability poor good
Manufacturing cost Poor to moderate Moderate to good
Manufacturing process

16. LetinAR Pin MR lens substrate sample
Mold core Extracted plastic combiner substrate Finalized
combiner module

17. Resin
injection
Coating
PinMR
Bonding
Various choice of optical materials
High compatibility with conventional manufacturing process
Low cost manufacturing
Finishing

18. Source: Arburg.com
Injection molding (example)
Optical coating (example)
Source: Schneider GmbH
Vacuuming Loading lenses Masking & optical
coating
Coated product

19. Lens module assembly (example)
Source: Fraunhofer IPT
Dispensing adhesive Adhesive calibration Positioning & assembly UV hardening & curing

20. Display modules (example)
Flat panel micro display can be used for a display module
LCoS
(North Carolina State University/Imagine Optix,
Nikkei BP)
Micro OLED
(Sony, Fraunhofer FEP)
Micro LED
(Jasper Display/Plessy, Samsung)

22. System Assembly

23. Cost comparison
DOE/HOE waveguide Half mirror waveguide PinMR combiner
Key process Nanoimprint lithography
/ Laser exposure
Coating / slicing Injection molding
Raw material Medium to high Medium Low to medium
Tooling Medium to high Medium to high low
Facility Medium to high Low to medium Low to medium
Tolerance Medium to high Medium to high Low to medium
Yield Medium Medium Medium to high
Manufacturing capacity Low to medium Low to medium Medium to high
Overall cost per unit High Medium to high Low to medium
No consideration for the optical performance

24. Moderate tolerance for
optical surfaces
Robust coating requirement
Flat mirrors
(Edmund Optics)
DigiLens waveguide example
(J. Waldern et al, Proc. SPIE 10676)
LetinAR combiner
Simple manufacturing steps
Surface relief grating manufacturing
(Captured from DigiLens talk, PW2019)
LetinAR 4-step manufacturing
How does it possible?

25. Mass production partnership
Korean Domestic Partners /
Global manufacturing partners

26. Lens Module
Special Purpose
HMD or Smartglasses with
OLEDoS
LCoS
MicroLED
μDisplay
Display manufacturer
Lens
+
Final Product
Manufacturer
Smart Glasses
Personal TV
AR/VR Monitor
- Smart Office -
Personal
Vehicles
Consumer
Sports
Medical
OEM
on demand
26
Military
Business collaboration
Use cases

27. Milestone for mass production
2021 Q1
Pilot production for
“Glasses-type”
optic solution
Pilot production for
“Goggle-type”
optic solution
Pilot production for
mass-production-ready
optic solution
Mass production
(expected
Q’ty of 320K /mth)