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A lens with a different shape forms the answer to Mrs. Miniver's problem, on finding a lens with half the area of the union of the two circles. Lenses are used to define beta skeletons, geometric graphs defined on a set of points by connecting pairs of points by an edge whenever a lens determined by the two points is empty.
For concave lenses, the focal point is on the back side of the lens, or the output side of the focal plane, and is negative in power. A lens with no optical power is called an optical window, having flat, parallel faces. The optical power directly relates to how large positive images will be magnified, and how small negative images will be ...
Various lens shapes, and the location of the principal planes. ʟ̩. Converging or positive lenses. 1 - Symmetrical double convex lens. 2 - Asymmetrical double-convex lens 3 - Plano- convex lens. 4 - Positive meniscus lens. Diverging or negative lenses. 5 - Symmetrical biconcave lens. 6 - Asymmetrical biconcave lens. 7 - Plano-concave lens.
The focal length f is considered negative for concave lenses. Incoming parallel rays are focused by a convex lens into an inverted real image one focal length from the lens, on the far side of the lens. Incoming parallel rays are focused by a convex lens into an inverted real image one focal length from the lens, on the far side of the lens
For a thin lens in air, the distance from the lens to the spot is the focal length of the lens, which is commonly represented by f in diagrams and equations. An extended hemispherical lens is a special type of plano-convex lens, in which the lens's curved surface is a full hemisphere and the lens is much thicker than the radius of curvature.
This list covers optical lens designs grouped by tasks or overall type. The field of optical lens designing has many variables including the function the lens or group of lenses have to perform, the limits of optical glass because of the index of refraction and dispersion properties, and design constraints including realistic lens element center and edge thicknesses, minimum and maximum air ...
A diagram showing the optical center of a spherical lens. N and N' are the lens nodal points. The optical center of a spherical lens is a point such that If a ray passes through it, then its lens-exiting angle with respect to the optical axis is not deviated from the lens-entering angle.
Diagram of Axicon and resulting Bessel Beam. An axicon is a specialized type of lens that has a conical surface. An axicon transforms a laser beam into a ring shaped distribution. [1] They can be convex or concave and be made of any optical material. The combination with other axicons or lenses allows a wide variety of beam patterns to be ...