Microlens Ray Trace
Trace rays through a superellipse microlens to visualize focusing behavior, spot size, and optical crosstalk as a function of lens geometry and chief ray angle.
Microlens Ray Tracing Simulator
Trace rays through a superellipse microlens onto a pixel photodiode. Adjust lens geometry and CRA to observe focusing and crosstalk.
Physics
The microlens is modeled as a superellipse profile, where the shape parameter controls the transition from a spherical lens to a more cylindrical form. Ray propagation follows Snell's law at each interface:
n₁ sin(θ₁) = n₂ sin(θ₂)
Key Parameters
- Lens height determines the focal length — taller lenses focus more tightly but are harder to fabricate
- Radius of curvature controls the numerical aperture and collection efficiency
- Shape parameter (superellipse exponent) adjusts the lens profile between circular and rectangular
- CRA angle simulates off-axis illumination from the camera lens; higher CRA shifts the focal spot and increases crosstalk into neighboring pixels
Crosstalk Mechanisms
Optical crosstalk occurs when focused light spills into adjacent pixels. The simulator shows how CRA-induced focal shift and lens aberrations contribute to this effect, motivating the use of CRA-dependent microlens offset in real sensor designs.
INFO
This is a geometric (ray) optics approximation. For pixels near or below the diffraction limit, wave-optics effects become significant — use RCWA or FDTD solvers for those cases.