Dot Projection
Single-surface 2-in-1 dot-projector for driver-monitoring and depth-sensing
Our demonstration systems highlight the remarkable capabilities of our record-breaking single-surface metalens dot projectors, unveiled in October 2023. These innovative projectors consist of a single surface adept at collimating light and projecting precise dot patterns. The use of a single surface not only streamlines the module design but also facilitates the creation of exceptionally compact dot-projector modules. We are showcasing three distinct configurations with fields of illumination (FOI) of 70° x 40°, 70° x 70°, and a record-setting 144° x 70°, all demonstrated live.
These projectors boast over 70% efficiency, less than 10% dot uniformity error, and high contrast ratios exceeding 40:1.
Dot Projectors
Dot projection optics are made with metaoptic according to customer specifications. The metaoptic are single surface (1M); typically used for 3D sensing (structured light and time of flight) for face unlock, short distance Lidar, etc.
NILT can design, prototype and manufacture metaoptic to state-of-the-art standards.
- Dot projection designed for stand alone, or to be used with external collimator
- Design freedom to match desired FoI with perfect N x M tiling
- Single-surface element allow for extreme miniaturization of optical system
- Extreme FOI possible
- Dot projectors can be designed both for collimated as well as divergent light sources with a high number of possible use cases
- All dot projectors can be optimized to customer requirements
Projected dot pattern with invisible horizontal tiling
See examples below:
- Dot projector 70×40 degree
- Dot projector 70×70 degree
- Dot projector 144×70 degree
- Collimator
Demonstrated specifications:
- Overall performance depends on design specs
- Diagonal FoI above 144° demonstrated
- Efficiency above 80% demonstrated for single surface combined collimation/fan-out function*
- Uniformity error below 5% demonstrated
- Contrast ratio above 60:1 demonstrated
*for fan-out of a collimated beam, 90% efficiency is demonstrated
NILT meta dot projector (left: module, right: element)
1. Dot projector 70 x 40 degree
The dot projector has a 3 x 3 tiling, FOI of 70⁰ x 40⁰, efficiency above 70%, and dot uniformity-error <10%, making it an ideal platform for most 3D sensing applications where low power consumption is critical.
| Dot projector | λ [nm] | FOI (X*Y) [⁰] | Tiling | Number of spots | Efficiency [%] | Dot uniformity error [%] | Contrast ratio |
|---|---|---|---|---|---|---|---|
| A | 940 | 70x40 | 3x3 | 2,952 | 82.9 | 8.5 | 60:1 |
| B | 940 | 70x40 | 3x3 | 2,925 | 78.7 | 3.7 | 60:1 |
2. Dot projector 70 x 70 degree
The dot projector has a 3 x 5 tiling, FOI of 70⁰ x 70⁰ and demonstrates an efficiency above 70% even with its relatively larger FOI.
| λ [nm] | FOI (X*Y) [⁰] | Tiling | Number of spots | Efficiency [%] | Dot uniformity error [%] | Contrast ratio |
|---|---|---|---|---|---|---|
| 940 | 70x70 | 5x3 | 4,875 | 73.9 | 5.1 | 42:1 |
3. Dot projector 144 x 70 degree
The dot projector has a 5 x 5 tiling, FoI of 144⁰ x 70⁰, yet maintains a dot-uniformity-error around 20% which is highly advantageous for applications such as in-cabin monitoring.
(The full projected pattern is pincushion distorted but the corners are clipped by the limited field of view of the detector)
| λ [nm] | FOI (X*Y) [⁰] | Tiling | Number of spots | Efficiency [%] | Dot uniformity error [%] | Contrast ratio |
|---|---|---|---|---|---|---|
| 940 | 144x70 | 5x5 | 8,125 | 67.1 | 20.9 | 41:1 |
4. Dot projection by collimator
This dot projector is based on collimation without fan-out. This means that the number of projected dots equals the number of emitter in the VCSEL array and the FOI is givel bu the focal length of the metalens collimator.
| λ [nm] | Tiling | Number of spots | Efficiency [%] | Contrast ratio |
|---|---|---|---|---|
| 940 | 1x1 | 325 | 85 | 166:1 |
Fan-out 2
| FOI | Non-uniformity (%) | Efficiency (%) |
|---|---|---|
| 70x50 | 15.6 | 77.6 |