LYCOS RETRIEVER 
Lens: Lenses
built 633 days ago
The oldest lens artefact is dated to c.640 BC, a rock crystal lens found at excavations in Niniveh. The earliest written records of lenses date to Ancient Greece, with Aristophanes' play The Clouds (424 BC) mentioning a burning-glass (a biconvex lens used to focus the sun's rays to produce fire). The writings of Pliny the Elder (23–79) ... show that burning-glasses were known to the Roman Empire[1], and mentions what is possibly the first use of a corrective lens: Nero was said to watch the gladiatorial games using an emerald[2] (presumably concave to correct for myopia, though the reference is vague). Both Pliny and Seneca the Younger (3 BC–65) described the magnifying effect of a glass globe filled with water.
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LENS will be a regional university facility for research, innovation, education and outreach with a national impact. The emphasis on cold and very cold neutrons makes it suitable for materials research, particularly in the area of nanoscale structures which are a research focus of many universities in the region. The flexible scheduling and technical resources available at IUCF make it ideal for developing innovative new neutron scattering techniques and instrumentation that will provide national benefits. At the same time, LENS's location in a university environment supports educational development at a local, regional and national level.
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Shamir is a leading provider of innovative products and technology to the progressive spectacle lens market. Utilizing its proprietary technology, the company develops, designs, manufactures, and markets progressive lenses to sell to the ophthalmic market. In addition, Shamir utilizes its technology to provide design services to optical lens manufacturers under service and royalty agreements. Progressive lenses are used to treat presbyopia, a vision condition where the eye loses its ability to focus on close objects. Progressive lenses combine several optical strengths into a single lens to provide a gradual and seamless transition from near to intermediate, to distant vision. Shamir differentiates its products from its competitors' primarily through lens design.
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Mortgage Lens doesn't require extensive training or a textbook-like instruction manual to use effectively. Mortgage Lens was designed from the ground up to be simple and easy to use. Just enter your numbers and you're ready to go.
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As mentioned above, a positive or converging lens in air will focus a collimated beam travelling along the lens axis to a spot (known as the focal point) at a distance f from the lens. Conversely, a point source of light placed at the focal point will be converted into a collimated beam by the lens. These two cases are examples of image formation in lenses. In the former case, an object at an infinite distance (as represented by a collimated beam of waves) is focused to an image at the focal point of the lens. In the latter, an object at the focal length distance from the lens is imaged at infinity. The plane perpendicular to the lens axis situated at a distance f from the lens is called the focal plane.
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Generally each curved surface of a lens is made as a portion of a spherical surface. The center of the sphere is called the center of curvature of the surface; every point on the surface is equidistant to it, this distance being the radius of curvature. The line joining the two centers of curvature ... passes through the optical center of the lens and is called the principal axis. Any other line through the optical center at an angle to the principal axis is called a secondary axis. In converging lenses all rays entering parallel to the principal axis are bent toward a point on the principal axis called the principal focus. The distance from the principal focus to the optical center of the lens is the focal length of the lens.
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