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CORRECTIVE OPTICAL LENSES
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Technical Examples
- An ophthalmic lens includes an optical zone having a center and a spaced-apart periphery. The optical zone has a first corrective power range in a first region and a second corrective power range in an annular region surrounding the first optical zone. The second corrective power is corrective of spherical aberration of an eye. The optical zone has a power profile that gradually changes from the first corrective power to the second corrective power. A central progressive zone that provides intermediate vision correction may be applied to a central region of the lens. The progressive zone has a diameter that is less than or equal to the diameter of an aperture of a pupil when subjected to bright light.
- An optical system includes a pair of adjacent cylindrical lenses and a target positioned in a round-spot plane following the pair of cylindrical lenses. At least one of the cylindrical lenses is rotatable about the optical axis, relative to the other cylindrical lens. A collimated light beam is incident on the pair of cylindrical lenses. Rotating the cylindrical lenses relative to each other allows changing the size of a round spot (or symmetrically scaling an image) at a given target location. Additional optical elements, for example a spherical lens, may be placed after the pair of cylindrical lenses. In various embodiments, the pair of cylindrical lenses may include two positive lenses, or a positive and a negative lens.
- A method of making corrective eyeglasses is disclosed. One embodiment is a method of making corrective eyeglasses. The method includes obtaining vision parameters of a patient's eyes, obtaining an eyeglass frame comprising at least one mounted optical element, and programming the optical element to define a pattern of refraction that is associated with the vision parameters.
- The lens unit includes an imaging lens including lenses, each of which includes a lens portion having an optical function and a flange portion on a periphery of the lens portion, and a ring-shaped lens holding member provided between the lenses and holds at least one of the lenses and a cylindrical-shaped lens-barrel including a lens holding portion that holds the imaging lens. The flange portion of each of the lenses is fittable to the flange portion of the other lens of the lenses, or the lens holding portion or an inner surface of the lens-barrel, and the lenses combined with each other through fitting to the flange portion of the other lens, the lens holding portion or the inner surface of the lens-barrel have respective shapes in which optical axes of the lenses coincide each other under a fitting state. The compact image pickup module includes the lens unit.
- A method of determining materials of lenses contained in an optical system of a projection exposure apparatus is described. First, for each lens of a plurality of the lenses, a susceptibility factor KLT/LH is determined. This factor is a measure of the susceptibility of the respective lens to deteriorations caused by at least one of lifetime effects and lens heating effects. Then a birefringent fluoride crystal is selected as a material for each lens for which the susceptibility factor KLT/LH is above a predetermined threshold. Theses lenses are assigned to a first set of lenses. For these lenses, measures are determined for reducing adverse effects caused by birefringence inherent to the fluoride crystals.
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