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  2. Burning glass - Wikipedia

    en.wikipedia.org/wiki/Burning_glass

    A replica (on a smaller scale) of the burning lens owned by Joseph Priestley, in his laboratory. A burning glass or burning lens is a large convex lens that can concentrate the Sun's rays onto a small area, heating up the area and thus resulting in ignition of the exposed surface.

  3. Lens - Wikipedia

    en.wikipedia.org/wiki/Lens

    The word lens comes from lēns, the Latin name of the lentil (a seed of a lentil plant), because a double-convex lens is lentil-shaped. The lentil also gives its name to a geometric figure. [a] Some scholars argue that the archeological evidence indicates that there was widespread use of lenses in antiquity, spanning several millennia. [1]

  4. Magnifying glass - Wikipedia

    en.wikipedia.org/wiki/Magnifying_glass

    A magnifying glass is a convex lens that is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle. Beyond its primary function of magnification, this simple yet ingenious tool serves a variety of purposes.

  5. Lens (geometry) - Wikipedia

    en.wikipedia.org/wiki/Lens_(geometry)

    A lens contained between two circular arcs of radius R, and centers at O 1 and O 2. In 2-dimensional geometry, a lens is a convex region bounded by two circular arcs joined to each other at their endpoints. In order for this shape to be convex, both arcs must bow outwards (convex-convex). This shape can be formed as the intersection of two ...

  6. List of lens designs - Wikipedia

    en.wikipedia.org/wiki/List_of_lens_designs

    Simple lenses are lenses consisting of a single element. Lenses in this section may overlap with lens designs in other sections, for example the Wollaston landscape lens is a single element and also a camera lens design. Basic types. Biconcave lens; Biconvex lens; Convex-concave lens; Plano concave lens; Plano convex lens; Meniscus lens; Designs

  7. Glasses - Wikipedia

    en.wikipedia.org/wiki/Glasses

    The use of a convex lens to form an enlarged/magnified image was most likely described in Ptolemy's Optics (which survives only in a poor Arabic translation). Ptolemy's description of lenses was commented upon and improved by Ibn Sahl (10th century) and most notably by Alhazen (Book of Optics, c. 1021).

  8. List of convexity topics - Wikipedia

    en.wikipedia.org/wiki/List_of_convexity_topics

    Convex lens - a lens in which one or two sides is curved or bowed outwards. Light passing through the lens is converged (or focused) to a spot behind the lens. Convex optimization - a subfield of optimization, studies the problem of minimizing convex functions over convex sets. The convexity property can make optimization in some sense "easier ...

  9. Camera obscura - Wikipedia

    en.wikipedia.org/wiki/Camera_obscura

    He suggested to use a convex lens to project the image onto paper and to use this as a drawing aid. Della Porta compared the human eye to the camera obscura: "For the image is let into the eye through the eyeball just as here through the window". The popularity of Della Porta's books helped spread knowledge of the camera obscura. [52] [53]