DE4121234A1 - High-refracting, aspherical lenticular glass for spectacles - is thin with flat outer curve with no disturbing alterations of refractive force. - Google Patents

Abstract

Through the combination of its basic properties with a large usable dia. an effective part of high reproductive quality and low volume appertains. The surface formation of the spectacle glass through the permanent transition of the second derivation of the meridian curve guarantees an optical permanent transition of the effective part to the bearer edge. The aspherical surface of the spectacle glass in the effective part is described by polynomials of the 6th or 8th order and in the bearer edge area by polynomials of the 3rd or 4th order. USE/ADVANTAGE - A spectacle lens glass with good reproduction properties, a high degree of wearing comfort and corresp aesthetic shape.

Description

The invention is applied in the manufacture of glasses glasses with good imaging properties, high stretcher comfort and corresponding aesthetic shapes of the lenses.

Eyeglass lenses with a high positive refractive index show at Use of conventional technologies (spherical surfaces) and materials (spectacle crown glass) enormous thicknesses and weights as well as high aberrations.

To reduce these disadvantages, especially for large diameters hold the following technologies, individually or in combination, have been applied:

• - aspherical cut
• - Use of light materials
• - lenticular shape

The patent DE 32 25 270 represents the state of the art "Eyeglass lens with high positive refractive index" and that on it building product "Perfostar" from Rodenstock Lenticular plastic glasses with an aspherical outer surface.

The disadvantages of these glasses are rated as follows:

• - Due to the low refractive index of the raw materials strong crown curvatures of the outer surface and high center thicknesses necessary so that glasses have a high effect even before existing smooth transition to the carry edge look unaesthetic.
• - The applied mathematical apparatus guarantees one steady transition of the 1st derivative of the meridian curves, However, higher order discontinuities occur so that none optically continuous transition from the active part to the transition zone to the supporting edge can be guaranteed.

The invention aims to address the disadvantages mentioned eliminate and sees the development more aesthetically pleasing Eyeglass lenses with good imaging properties and high Comfort even in the extreme positive diopter range.

According to the invention, an aspherical lenticular spectacle lens Made of high-index material, the following conditions Fulfills:

• a) Classic lenticular glasses with geometrically clear delimited wearing edge, being on the spectacle lens according to the invention the boundary of the functional part is not recognizable and the Geometric delimitation of the supporting edge only on the negative Curvature in the transition area can be perceived.
• b) full-lens (no change in the sign of the curvature the meridian curves)

According to the invention, a thin lenticular spectacle lens is created with a flat outer curve, which is the same due to the small volume Has weight advantages like conventional eyeglass lenses Plastic. The lens has an aspherical lens Effective part excellent imaging properties and by a steady transition of the 2nd derivative of the meridian curves becomes a optically continuous transition of the effective zone to the carrying edge guaranteed (i.e. no disturbing, sudden changes in refractive power and the aberration and thus better uses the peripheral areas for peripheral vision).

An embodiment of the invention is intended to address the inventive concept describe in more detail.

The lens presented has a peak calorific value of S ′ = 10 dpt. This is due to a vertex on the object side radius of R₁ = 4,60028 cm and an eye side of R₂ = 11.62 cm realized.  

The shape of the raised, object - side surface is determined by the Meridiankure described the following mathematical Dar position owns:

z (h) = 2.30014 cm · ρ + 0.321727 cm · ρ²
+ 0.234897 · ρ³

The size ρ is used as a calculation tool is well suited:

The asphere defined in this way has with respect to the astigmatism excellent optical properties. For infinitely distant objects is the astigmatic error at Viewing directions up to 35 ° with respect to the optical axis absolutely less than 0.01 dpt.

At a distance h _w = 1.7864 cm from the optical axis, the effective zone merges into the wearing edge. At this point the effective zone has an angle of inclination of δ = 22.1665 ° with respect to the normal to the optical axis. The radius of curvature is (meridional) R _m = 4.98708 cm.

Outside the effective zone, the meridian curve is represented by polynomials representing the edge of the strap:

z (h) = e₀ + e₁ h + e₂ h² + e₃ h³

The coefficients decrease depending on the area under consideration Wear the following values:

h _s is the distance from the optical axis for which the two supporting edge parts merge continuously (optically continuously) into one another until the second derivative.

The parts of the support rim are designed so that the concave curvature in the throat of the lenticular shape does not fall below a radius of R _k = 4.75 cm; the carrying edge is characterized by a flat, aesthetically pleasing shape.

The shape at the edge of the lens should be emphasized. Here be the shoulder edge has the same inclination and curvature as the refractive surface on the outside. That way keeps the carrying edge is almost constant across larger spatial areas Thickness.

The lens presented has a thickness of d _r = 1.6 mm at its edge of the support. If your free diameter for gripping is reduced by 5 mm, the edge thickness increases to 1.60667 mm. Reducing the free diameter by 2 cm increases the edge thickness by 0.426 mm.

Claims (3)

1. Highly refractive aspherical lenticular single vision glass, characterized in that the combination of these properties with a large usable diameter results in a functional part of high quality and low mass. 2. High-refractive aspherical single-vision glass after Claim 1 characterized, that the surface design of the glasses through the steady transition of the 2nd derivative of the meridian curves, an optically continuous transition of the functional part to Carrying edge guaranteed. 3. High-index single-vision aspherical lens according to claims 1 and 2 characterized, that the aspherical surface of the lens in the functional part by 6th or 8th order polynomials and in the supporting rim range is described by 3rd or 4th order polynomials.