摘要:
A medium-exchangeable storage device can be configured to serve as the underlying storage medium for file system and as a data backup medium. A technique is described which allows a medium-exchangeable storage device to services as a file system and as a backup device.
摘要:
In a process of determining the surface shape of each of progressive multifocal lenses for use as lenses in eyeglasses, radii of curvature at main points are calculated, and then the surface is divided into a plurality of lattice sections, and then a curved-surface equation in the form of a bicubic expression is used for each section to determine the surface shape of the lens. A coefficient of each of the bicubic expressions is determined under a condition that continuation is established to curved-surface equations of sections adjacent at a boundary line between the sections to the derivatives of second order. Therefore, the surface shape of the lens obtained by the curved-surface equation for each section can be formed into a continuous and smooth surface. Since the curved surface can be determined for each section, a partial correction can easily be performed, if necessary. As a result, a progressive multifocal lens can be provided which exhibits smooth astigmatism curves and a large clear field of vision to meet a variety of specifications. Thus, lenses for eyeglasses each having a clear field of vision can be provided.
摘要:
A progressive-power lens includes an eyeball-side surface including a distance portion and a near portion having different values of dioptric power. An intermediate portion connects the distance portion and the near portion to each other. An object-side surface of the progressive-power lens includes a first region extending along a principal meridian and having a spherical shape having first curvature, a second region facing the distance portion and having a spherical shape having second curvature equal to the first curvature, and a third region located outside the first region and below the second region and having third curvature greater than the first curvature.
摘要:
A method of designing a progressive power lens group as a set of progressive power lenses, each having a first refractive section having a refractive power for seeing an object located at a predetermined distance, a second refractive section having a refractive power for seeing an object located at a near distance, and a progressive section with its refractive power progressively changing from the first refractive section to the second refractive section, the progressive power lens group satisfying: a condition where the first refractive sections differing in refractive power can be selected; a condition where at least two additions can be selected for the first refractive section having an identical refractive power; a condition where refractive indexes of materials of the progressive power lenses are identical; and a condition where design concepts of the progressive power lenses are standardized, the method includes designing the progressive power lenses so that for the progressive power tenses identical in addition, the smaller the refractive power of the first refractive section is, the shorter a distance in a vertical direction between a fitting point and a refractive power measurement point of the second refractive section is, and for the progressive power lenses identical in the refractive power of the first refractive section, the larger the addition is, the longer the direction in the vertical direction between the fitting point and the refractive power measurement point of the second refractive section is.
摘要:
A progressive power lens is conventionally so designed that a distance portion and a near portion are linked together in a successive manner, and thus framing cannot be done in a manner as to fully achieve the best optical properties of the near portion. The present invention provides, on the other hand, a progressive power lens that is designed to make the near portion closer to an eyeball without impairing the optical properties of the progressive power lens. Accordingly, both the distance portion and the near portion can be framed with the ideal fitting, and the resulting eyeglasses can be less in distortion and fluctuation.
摘要:
This semiconductor photodetector includes a photoabsorption layer, an n-type first semiconductor layer, and a p-type second semiconductor layer. The photoabsorption layer comprises an n-type first layer and a p-type second layer formed in contact with the first layer. The first semiconductor layer is arranged on the side of the first layer and has a shorter wavelength at a light absorption edge and a lower refractive index than in the photoabsorption layer. The second semiconductor layer is arranged on the side of the second layer and has a shorter wavelength at a light absorption edge and a lower refractive index than in the photoabsorption layer. When a predetermined reverse bias voltage is applied between the first and second semiconductor layers, the first layer is entirely depleted and the second layer is partially depleted.
摘要:
In a multifocal lens for eyeglass provided with visual field areas having different refractive powers, being a distance-vision area and a near-vision area, a multifocal lens for eyeglass (10) is provided, in which the difference of the average surface power D11 of the distance-vision area (11) of the surface (2) on the side of the object and the average surface power D12 of the near-vision area (12) is made mathematically less than the addition power Add. Furthermore, a specific addition power Add is provided by adjusting the average surface power D21 of the distance-vision area of the surface (3) on the side of the eye and the average surface power D22 of the near-vision area. It becomes possible to adjust the average surface powers D11 and D12 of the surface (2) on the side of the object such that the difference of magnification of the distance-vision area and the near-vision area becomes little. Furthermore, it is also possible to make the difference of the average surface powers D11 and D12 of the surface (2) on the side of the object little. Consequently, a multifocal lens can be provided, whereby a comfortable visual field can be obtained, in which there is little jumping and warping of images due to the difference of magnification, and furthermore, the clear-vision area having improved astigmatic aberration is wide, and there is little jumping of images, and the like.
摘要:
A progressive-power lens has one surface which satisfies the following expressions CY(DP)=CT(DP) CY(P)>CT(P) where CT(DP) denotes a vertical direction curvature at the distance reference point, CY(DP) denotes a horizontal direction curvature, CY(P) denotes a horizontal direction curvature at a point on the principal meridian which is located further on the near portion than the progressive start point, and CT(P) denotes a vertical direction curvature at the point.
摘要:
Spectacle lenses that allow a wearer to view an object in a more comfortable manner include a pair of lenses for the left and right eyes. The power of one of the pair of lenses is shifted toward the positive side with respect to the power of the other lens, and object-side average surface power (base curve) of the one lens is smaller than object-side average surface power (base curve) of the other lens. The power (dioptric power) is principal meridian power along a principal meridian of each of the lenses, and the base curve is in the direction along the principal meridian.
摘要:
A progressive-power lens having an eyeball-side surface including a distance portion and a near portion having different values of dioptric power and an intermediate portion that connects the distance portion and the near portion to each other, and an object-side surface including a spherical first region having a first curvature and extending along a principal meridian, a spherical second region having a second curvature equal to the first curvature and facing the distance portion, and a third region located outside the first region and below the second region and having a third curvature smaller than the first curvature.