Lubor’s Lens, often associated with the Invisible Shield trick, is a clever optical illusion created by magician Lubor Fiedler. It uses a special fresnel lens-like plastic sheet that distorts light in such a way that it appears to make an object disappear when placed behind it.
How It Works
- Refraction and Light Bending: The plastic lens redirects light in a way that prevents the viewer from seeing objects directly behind it.
- Angle-Based Illusion: The design forces light to scatter or bend around the object, blending it into the background.
- Selective Transparency: Unlike regular lenses, Lubor’s Lens does not magnify or invert images but instead disrupts direct visibility in a controlled manner.
Technology & Design
- Made from a specialized plastic sheet with microstructures that affect light transmission.
- Works similarly to lenticular lenses, which are often used in 3D postcards and privacy screens.
- Instead of focusing light, it redirects and diffuses it, making objects seem invisible from specific angles.
Refraction Principles
Refraction occurs when light passes from one medium to another, changing its speed and direction due to the difference in refractive indices. The key equation governing refraction is Snell’s Law: n1sinθ1=n2sinθ2n_1 \sin \theta_1 = n_2 \sin \theta_2n1sinθ1=n2sinθ2
where:
- n1n_1n1 and n2n_2n2 are the refractive indices of the two media,
- θ1\theta_1θ1 is the angle of incidence, and
- θ2\theta_2θ2 is the angle of refraction.
Lubor’s Lens uses a structured plastic sheet with varying refractive indices and micro-ridges that force light to bend unpredictably.
Light Bending Mechanism in Lubor’s Lens
Lubor’s Lens does not function as a traditional smooth lens but rather relies on a specialized surface that redirects light to create an illusion:
A. Microlens Array / Fresnel-like Pattern
- The sheet is embedded with a microscopic pattern of convex and concave lens structures that scatter incoming light.
- Unlike a conventional lens that focuses light, these ridges deflect light rays outward, preventing a clear image from forming.
B. Angular Light Diffusion
- Instead of transmitting light directly, Lubor’s Lens disperses and redirects the rays in such a way that they blend into the background.
- The angle of incoming light determines whether an object behind the lens is visible or obscured.
C. Edge Gradient and Optical Camouflage
- Objects placed behind the lens appear distorted or invisible because the light bypasses direct transmission and merges with surrounding light.
- This effect is similar to stealth cloaking techniques, where light is manipulated to hide objects.
Comparison to Other Optical Systems
| Feature | Lubor’s Lens | Traditional Glass Lens | Lenticular Lens |
|---|---|---|---|
| Function | Light diffusion & camouflage | Image magnification or focusing | Image directionality control |
| Surface Structure | Microstructured ridges | Smooth curved glass | Parallel ridges |
| Light Behavior | Scatters & distorts | Refracts and focuses | Changes image depending on viewing angle |
| Application | Optical illusions, magic tricks | Eyeglasses, cameras, telescopes | 3D images, privacy screens |