草榴社区 Cloud
Cloud native EDA tools & pre-optimized hardware platforms
Request a Free Trial →
Definition
BSDF stands for? Bidirectional Scattering Distribution Function, which is a mathematical function that characterizes how light is scattered from a surface.
It is mathematically defined by the following formula:
Where:
- L is the luminance on the sample surface at the observer direction
- E is the illuminance on the sample surface from the source direction
- Λ is the wavelength
It is mathematically defined by the following formula:
In practice, this phenomenon is usually split into reflected and transmitted components, which are then treated separately as BRDF (Bidirectional Reflectance Distribution Function) and BTDF (Bidirectional Transmittance Distribution Function).
Why is BSDF Important to an Optical Design?
During an optical design process, accurate simulation results rely on accurate optical properties. Indeed, geometry alone does not determine light distribution; it’s the optical properties that determine how the energy and direction of the rays change. For this reason, it’s important to know as precisely as possible the optical characteristics of the materials that will be used. The best way to obtain precise characteristics is to measure the material directly and export the data to use in an optical software tool.
Requirements:
- Optical designers need accurate optical properties for ray tracing simulations
- R&D engineers need to design the right material with given optical properties
- The quality check in the manufacturing process must be perfectly controlled
草榴社区:
- Angular optical scattering with BSDF
- Amount of light propagation TIS (Reflectance, Transmittance, Absorbance ratio)
What Solution Does 草榴社区 Offer for Measuring BSDF?
There are two principal ways to measure BSDF: goniophotometer and camera-based system. 草榴社区 provides two solutions for both.
Goniophotometer
You can measure BSDF with a classical goniophotometer, where a static light source illuminates a sample, and a mobile detector turns around the sample to collect the scattered light (or the opposite – with a mobile light source and a static detector).
草榴社区 offers two goniophotometer solutions: the 草榴社区 REFLET 180S and the High Specular Bench.
For these high-resolution, high dynamic motorized scatterometer systems, we provide measurement services in our lab, but the 草榴社区 REFLET 180S is also available for purchase.
| 草榴社区 REFLET 180S | 草榴社区 High Specular | |
|---|---|---|
| Type | BRDF/BTDF | BRDF/BTDF |
| Dynamic range | 109 | 1013 |
| Wavelength range | 400nm to 1700nm | 280nm to 10,6µm |
| Incident angles | Tunable: +90° to -90° | Tunable: 90° to 0° |
| Angular range | Full sphere | 1 Plan from -10° to +90° |
| Angular accuracy | < 0.1° | < 0.02° |
| Repeatability | < 1% | < 1% |
| Weight | 80 kg | 200 kg |
| Advantages |
|
|
|
||
Camera-Based System
You can also measure BSDF using a camera-based system, where a source illuminates the sample and a system of lenses sends all the scattered light to a camera.
草榴社区 develops and assembles two camera-based systems: the 草榴社区 Mini-Diff V2 and the 草榴社区 Mini-Diff VPro, and both are available for purchase. The 草榴社区 Mini-Diff VPro (left) is delivered with its own “dark room” and temperature control. The Mini-Diff V2 (right) is a portable device that is fast and easy to use.
| 草榴社区 Mini-Diff V2 | 草榴社区 Mini-Diff VPro | |
|---|---|---|
| Type | BRDF/BTDF | BRDF/BTDF |
| Dynamic range | 105 | BRDF 105 BTDF 106 |
| Wavelength range | 630nm, 525nm, 465nm, 940nm | 630nm, 525nm, 465nm |
| Incident angles | Fixed: 0°, 20°, 40°, 60° | Tunable: 0° to 60° |
| Angular range | Sphere [0° ; 75°] [0° ; 360°] | Sphere [0° ; 75°] [0° ; 360°] |
| Angular accuracy | 1° | 0,5° |
| Repeatability | <2% | <2% |
| Weight | 2 kg | 42 kg |
| Advantages |
|
|
All of these instruments enable you to export measurement data into simulation software to be used for design.
Optical Scattering Measurements & Equipment
Precision Light Scatter Data for Faster, More Cost-Effective Optical Product Development
Example of a Vehicle Dashboard Measurement with the 草榴社区 REFLET 180S and Design with LucidShape
The measurements of a surface for vehicle dashboard material can be used in R&D to evaluate the grain size to determine which one reflects the least and scatters the most. The goal is to have the most diffusing surface possible in order to decrease reflection in the windshield for driver safety.
To compare the scattering of two dashboard surfaces with different grain sizes, the measurement of the BRDF is performed for four angles of incidence (AOI=10°/30°/50°/70°) with a white light.
For both surfaces, there is a large Gaussian peak with scattering on each side and a Lambertian background.
The level of the background is similar, but Reference 1 is more specular and Reference 2 is more diffusive; this shows that Reference 2 is more suitable for use as a dashboard.
Thanks to the capability of exporting the measurement data to design software, you can use this data to perform a simulation in LucidShape.
Using the data in LucidShape, you can perform a simulation and draw the same conclusion: Reference 1 is more specular and Reference 2 is more diffusive, which means the driver will be experience less glare with Reference 2.
Directly measuring the BSDF enables designers to choose the right material or coating, achieve an accurate rendering, and reduce the cost of prototyping.
Continue Reading
Blog
4 min read
/
Nov 18, 2024
AI Startups are Using the Cloud to Accelerate Chip Design and Time-to-Market
Blog
6 min read
/
Nov 11, 2024
Post-Quantum Cryptography: Safeguarding the Future of Digital Security
Blog
3 min read
/
Oct 30, 2024
Flash Forward: MRAM and RRAM Bring Embedded Memory and Applications into the Future
Blog
4 min read
/
Oct 28, 2024
Hardware-Assisted Verification: Unlocking the Future of Chip and System Design
Blog
4 min read
/
Oct 21, 2024
Accelerating AI Chip Development and Reducing Risk with Pre-silicon, Secure, Cloud-based Emulation
