What distinguishes Fresnel lenses from traditional lenses?

What distinguishes Fresnel lenses from traditional lenses?

• A. They are made of glass rather than plastic
• B. They use multiple layers instead of a single piece
• C. They have concentric grooves making them thinner and lighter
• D. They can only be used for focal lengths less than one meter

Answer: (C)

Fresnel lenses are uniquely designed with a series of concentric grooves that allow them to be significantly thinner and lighter compared to traditional lenses. This design mimics the optical properties of a much thicker and heavier lens but achieves the same focal length and light-bending capabilities. The grooves reduce the amount of material needed while maintaining the lens's ability to focus light effectively, making them ideal for applications where weight and size are critical, such as in lighthouses, projectors, and various optical devices. This characteristic of being thinner and lighter is a fundamental innovation in lens design that distinguishes Fresnel lenses from conventional lenses, which are typically crafted from a solid piece of glass or plastic.

Fresnel lenses are uniquely designed with a series of concentric grooves that allow them to be significantly thinner and lighter compared to traditional lenses. This design mimics the optical properties of a much thicker and heavier lens but achieves the same focal length and light-bending capabilities.

The grooves reduce the amount of material needed while maintaining the lens's ability to focus light effectively, making them ideal for applications where weight and size are critical, such as in lighthouses, projectors, and various optical devices. This characteristic of being thinner and lighter is a fundamental innovation in lens design that distinguishes Fresnel lenses from conventional lenses, which are typically crafted from a solid piece of glass or plastic.