JP2913191B2 - Aspheric lens design method and processing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an aspherical lens as an eye refraction correcting means such as an intraocular lens and a contact lens, and an apparatus for manufacturing the same.

(Prior Art) Conventionally, for example, an asphericity of an intraocular lens is represented by an even-order polynomial of a deviation from a spherical surface, ray tracing is performed while changing coefficients of the polynomial, and aberrations are calculated and designed. Or
Alternatively, a method of expressing and designing an aspheric surface by using a special algebraic function instead of a polynomial has been generally used.

(Problems to be Solved by the Invention) The conventional means described above has a drawback that the expression of the aspherical surface is limited to an expression that can be expressed by an algebraic function, and the degree of freedom of design is limited.

For example, in the case of a refraction curved surface that is to be rotated about the optical axis, the radius of curvature at that point is determined by the distance from the optical axis. If this radius of curvature is represented by the radius of curvature of the distance from the optical axis, the two different radii of curvature have a fixed relationship depending on the form of the algebraic function, and the radii of curvature at those points must be changed independently. Could not.

For this reason, in general, the method of using an algebraic function to represent an aspheric surface has a limited degree of freedom in design. For example,
It was impossible to design an intraocular lens or the like from which spherical aberration was completely removed.

In general, in an eyeball optical system, the image quality in the fovea of the macula affects visual acuity, and therefore, how to control spherical aberration is one of the important issues in the manufacture of intraocular lenses and contact lenses.

The present invention provides an aspheric lens such as an intraocular lens having an arbitrary depth of focus or a resolution by completely removing the spherical aberration by arbitrarily controlling the spherical aberration, a method of manufacturing the same, and an apparatus for manufacturing the same. That is the task.

(Means for Solving the Problems) In order to solve the above problems, the present invention sets the shape of the refraction surface of the lens to be designed, instead of using an algebraic function as in the related art, but from the optical axis. Determine the slope of the curved surface at the point where the light beam passes so that the light beam passing through the arbitrary height passes through a predetermined desired final passing point after passing through the lens. The shape of the entire curved surface is designed based on the inclination of the curved surface in.

That is, the present invention has been made as a method for manufacturing an aspherical lens and an apparatus for manufacturing a lens. The feature of the method for manufacturing a lens is that a method for manufacturing an aspherical lens using a ray tracing method has a certain incident light ray R. Ray tracing to determine the position of the intersection point PT between the ray R and a specific refraction surface, and setting the desired final passage point P0 that the ray R passing through the intersection point PT passes after refracting the final refraction surface And determining the slope T of the curved surface at the intersection PT appropriately, and obtaining the final passing point P of the light ray R corresponding to the slope T of the curved surface. Comparing the position of the desired final pass point P0 and sequentially changing the slope T of the curved surface so that the position of the final pass point P matches the position of the desired final pass point P0; When coincidence with the passing point P0, Determining the slope T of the curved surface as the slope of the desired refraction surface at the intersection PT, and sequentially changing the height h or the angle of the incident ray R with respect to the optical axis L to continue to the set curved surface whose slope has been determined. Intersection of curved surfaces
Calculating PT ′ and changing the slope T ′ of the curved surface; and when the final passing point P ′ matches the desired final passing point P0 ′, the slope T ′ of the curved surface is converted to the desired refracted curved surface at the intersection PT ′. Determining the inclination, calculating the shape of the curved surface from the inclination T of the refraction surface at each intersection PT thus repeatedly determined, and manufacturing a lens based on the individually determined shape of the curved surface. And step.

The feature of the aspherical lens manufacturing apparatus is that, in the aspherical lens manufacturing apparatus using the ray tracing method, ray tracing is performed for a certain incident ray R, and the intersection point PT of the ray R and the refraction curved surface is determined. Intersection position determining means 15 for determining the position,
Objective value setting means 13 for setting a desired final passing point P0 through which the ray R passing through the intersection PT passes after refracting the final refraction surface, and inclination determining means 14 for appropriately determining the inclination T of the curved surface at the intersection PT.
And a final passing point calculating means 16 for obtaining a final passing point P of the light beam R corresponding to the inclination T of the curved surface determined by the inclination determining means; and the final passing point P and the preset desired final passing point P0. And sequentially changing the slope T of the curved surface of the slope determining means so that the position of the final passing point P matches the position of the desired final passing point P0.
A determination means 17 for determining the slope T of the curved surface at the time of coincidence with P0 as the slope of the desired refraction curved surface at the intersection PT; and an initial value for sequentially changing the height h or angle of the incident light beam R with respect to the optical axis L. The intersection point PT 'of the setting surface 11 and the curved surface that is continuous with the set curved surface whose inclination has been determined is determined, and the intersection point PT' and the inclination T 'of the curved surface are changed to obtain the final passing point P'.
And the desired final passing point P0 ′, the inclination of the refraction surface is determined, and the inclination T of the surface at the position of each intersection PT, and the surface shape calculation means 18 that calculates the shape of the surface from the inclination T,
A storage device 5 for storing the curved surface shape obtained by the curved surface shape calculation means 18, and a lens can be manufactured using the numerical controller 6 based on the information in the storage device 5. It is in.

(Operation) In the present invention configured as described above, the inclination T of the curved surface at a predetermined height h from the optical axis L of the specific refraction surface is such that the incident light R passing through the height h is the final refraction surface. After passing
It is determined to pass through a predetermined final passing point P0 specified in advance.

Then, the height h or angle of the incident light beam R is sequentially changed, and the shape of the entire curved surface is calculated and designed from the value of the inclination at each height h of the curved surface.

That is, a refraction curved surface having a specific line segment of the optical system is selected as a design curved surface, and the means according to the present invention is applied to the curved surface.

By ray tracing, the position of the intersection PT where the incident ray R passes through the refraction curved surface (the height from the optical axis and the distance in the optical axis direction) is obtained,
The slope T of the curved surface at the intersection PT is changed one after another.

Specifically, the slopes T1 and T2 of the first two refraction surfaces are determined arbitrarily, and the third and subsequent slopes are the two preceding slopes and the two final passing points P corresponding to the slopes of the respective refraction surfaces. From this and the desired final pass point P0, the slope T of the next curved surface can be determined by interpolation or extrapolation.

In this way, the slope T of the curved surface at the intersection PT is determined, and when the final passing point at the slope T coincides with the desired final passing point P0, the slope T of the refracted curved surface becomes the desired slope of the curved surface. Is set.

Further, the height h of the incident light beam R is sequentially changed, the inclination of the curved surface at different heights h is similarly determined, and the shape of the curved surface at each intersection PT is sequentially set.

Also, when the incident light R is incident from the side near the optical axis L and the angle is gradually increased, the inclination of the curved surface can be similarly determined from the portion of the curved surface close to the optical axis.

A light ray incident on an arbitrary refraction curved surface determined as described above always passes through a desired final passing point P0.

(Example) Hereinafter, a case will be described in which an example of the present invention is applied to an intraocular lens for removing spherical aberration of an eyeball optical system.

FIG. 1 is a flowchart of an embodiment according to the present invention, FIG. 2 is a schematic diagram of an eyeball having an intraocular lens mounted thereon, and FIG. 3 is a block diagram of the apparatus.

In FIG. 3, 1 is a computing device, 2 is a storage device, 3 is a display device, 4 is a keyboard, 5 is a storage device, 6
Is a numerically controlled lathe.

The computing device 1 comprises a CPU, and designs a lens according to a control program written in a memory (not shown).

The storage device 2 includes a radius of curvature of each of the anterior and posterior surfaces of the cornea and the anterior and posterior surfaces of the intraocular lens required for designing the intraocular lens, a distance between the respective refracting surfaces of the cornea and the intraocular lens, and a medium. Refractive index, information on which refracting surface is to be designed, the initial value of the tracking ray and the initial value of the tracking ray, if the height from the optical axis changes,
Alternatively, information on whether the angle changes, the pitch of the change, or information for setting the target value is stored.

Numeral 11 denotes initial value setting means 11 for sequentially changing the height h or angle of the incident light R with respect to the optical axis L, and is incorporated in the computing device 1.

13 is a target value setting means built in the computing device 1,
A desired final passing point P0 of the light beam at each intersection PT between the curved surface and the light beam R designed by the reading means 10 based on the information appropriately read from the storage device 2 is obtained.
In the present embodiment, since the intraocular lens is designed without spherical aberration, the desired final passing point P0 is one common point.

Reference numeral 14 denotes an inclination setting means, which can arbitrarily determine an inclination T of a curved surface to be designed.

Reference numeral 15 denotes an intersection PT position determining means for determining the position of the intersection PT (the height h from the optical axis and the position in the optical axis direction) of the ray R traced by the ray tracing means 12 and the designed curved surface.

Numeral 16 denotes a final passing point calculating means for tracing the ray R at the inclination T of the curved surface appropriately determined by the inclination setting means 14 by the tracing means 12 to obtain the final passing point P.

17 compares the final passing point P obtained by the final passing point calculating means 16 with the desired final passing point P0, and determines whether the final passing point P matches the desired final passing point P0. In the first determination means for comparing and confirming, the inclination setting means 14 is repeatedly applied based on an interpolation method or an extrapolation method until these final passing points and the desired final passing point P0 match. It is configured.

Numeral 18 denotes a curved surface shape calculating means, which sequentially changes the height h or angle of the incident light beam R to calculate the shape of the curved surface from the position of each intersection PT and the inclination of the refraction curved surface at the intersection PT. Is what you do.

Reference numeral 19 denotes second determining means for confirming whether or not the shape of the curve is completely determined. When the shape of the curve is completely determined, the information is stored in the storage device 5 via the data writing means 20. The numerical control lathe 6 is operated based on the written data.

The apparatus according to the present invention has the above configuration, and a case where a lens is manufactured using the apparatus will be described with reference to FIG.

First, by selecting the keyboard 4, a specific file in the storage device 2 is selected, and the predetermined information is read out by the reading means.
10 and read out by the initial value setting means based on the information.
11, the initial value of the first trace ray R is set. The ray tracing is performed on the initial value of the ray by using the ray tracing means 12, and a passing point (height from the optical axis h on the design surface) on the designed curved surface is obtained.
And the position in the optical axis direction) are obtained by the intersection position determining means 15, and one desired final passing point P0 with respect to each intersection PT of the design curved surface is obtained by the target value setting means 13.

Next, the inclination T1 of an arbitrary curved surface at the intersection point PT is determined by the inclination setting means 14, ray tracing is performed at the inclination T1 of the curved surface, and the final passing point P1 of the light ray is obtained by the final passing point calculating means 16. . The first determination means 17 compares and confirms whether the final pass point P1 matches the desired final pass point P0.

When the final passing point P1 matches the desired final passing point P0, the slope T1 of the curved surface is determined as the slope of the desired curved surface.

If the final passing point P1 and the desired final passing point P0 do not coincide with each other, a slope T2 of the refractive surface different from the slope T1 of the refractive surface at the intersection PT is further determined, and the slope of the refractive surface is determined. The final passing point P2 at T2 is obtained in the same manner as described above.

Then, it is checked whether or not the final passing point P2 and the desired final passing point P0 match, and when both P0 and P2 match, the inclination T2 of the refraction curved surface is set as a desired inclination. Once determined, and in the case of a mismatch, the slope of the new surface is also determined.

That is, the slope T of the third and subsequent curved surfaces is obtained by interpolation using the preceding two slopes, the corresponding final pass points P obtained by ray tracing, and the desired final pass points P0. Alternatively, it is determined by an extrapolation method. Then, a final pass point P corresponding to the determined inclination of the curved surface is obtained, and the final pass point and the desired final pass point P0 are compared and confirmed again by the first determination means 17, and the final pass point P is determined.
Until the desired final pass point P0 coincides with the next intersection point
The inclination of the curved surface at PT is repeatedly changed and determined by the inclination setting means 14, and when the two final passing points coincide, the inclination T at that time is set as the desired inclined surface.

If the slope T of the curved surface changes one after another and the distance of the intersection PT in the direction of the optical axis L is changed when the final passing point P is obtained, the change is determined by the intersection PT position determination means 15. I do.

Further, the initial values are sequentially changed by the initial value setting means 11, the slopes T of the curved surface at different incident light rays R are obtained one after another, and the shape of the curved surface is sequentially determined by the curved surface shape calculating means 18. That is, the height h or the angle of the incident light beam R with respect to the optical axis L is sequentially changed to change the intersection P
T ′ is determined, and the intersection P is determined so that the final passage P ′ of the light beam passing through the intersection PT ′ coincides with the desired final passage P0 ′.
The inclination T 'of the refraction curved surface at T' is obtained. The shape of the curved surface is calculated from each of the intersection points PT repeatedly obtained and the inclination T of the refraction curved surface at the intersection point PT.

When the shape of the curved surface is sequentially determined, the curved surface shape becomes a reference for calculation at the next height. That is, the position of the intersection point PT between the ray R and the design surface in the direction of the optical axis L changes according to the design. This change is caused by the shape of the determined surface (set surface) and the next surface following the surface. Is calculated using the slope T of

Then, the second determination means 19 confirms whether or not the shape of the curved surface has been completely set, and if the shape is determined, the data of the curved surface shape is written by the writing means 20,
The data is written into the storage device 5, and the numerical controller 6 operates based on the data, and the numerical controller 6 processes the lens.

In the lens formed as described above, since the refraction curved surface is designed so that the incident light ray R at the intersection point PT always passes through the desired final passage point P0, it is possible to manufacture lenses having various properties. It is.

For example, if the desired final pass point P0 is set to a common point for each height, it becomes possible to manufacture a lens with spherical aberration completely removed, and the desired final pass point P0 is set to two points. Then, a lens having a double focus can be manufactured.

When a lens having a plurality of focal points is manufactured, the position of the last passing point corresponding to each intersection is stored in advance in the target value setting means.

Further, according to the present invention, it is also possible to separately design a plurality of continuous curved surfaces having a predetermined area and connect the respective curved surfaces.

(Effect of the Invention) Since the present invention is configured as described above, it is possible to easily manufacture a lens in which spherical aberration is completely removed from a specific conjugate point within the range of geometrical optics.

Further, the desired final passing point at a desired height with respect to the optical axis of the lens can be changed more easily than in the past. For example, if two desired final passing points are provided, a lens having a bifocal point Can be manufactured.

Therefore, it is particularly suitable for the production of clear and visible intraocular lenses and contact lenses without spherical aberration.
Moreover, since the spherical aberration can be set arbitrarily and a double focus or multifocal lens can be precisely processed, its practical value is remarkable.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment according to the present invention,
FIG. 2 is a schematic view showing an optical system of an eye into which an intraocular lens is inserted, and FIG.
The figure is a block diagram of the apparatus for lens processing. PT, PT '... intersection, h ... height from optical axis, P0, P0' ...
Desired final passing point, P (P1, P2), P '... Final passing point, T
(T1, T2), T ': slope of the curved surface, 11: initial setting means, 1
2 ... ray tracing means, 13 ... target value setting means, 14 ... inclination setting means, 15 ... intersection position determining means, 16 ... final passing point calculating means, 17 ... first determining means (determining means) , 18 ……
Curved surface shape calculation means, 19 ... second determination means.

Claims (2)

(57) [Claims] 1. A method of manufacturing an aspheric lens using a ray tracing method, wherein ray tracing is performed on a certain incident light ray R,
Determining a position of an intersection PT between the ray R and a specific refraction surface; setting a desired final pass point P0 through which the ray R passing through the intersection PT refracts the final refraction surface; Appropriately determining the slope T of the curved surface, obtaining a final passing point P of the light ray R corresponding to the slope T of the curved surface, and determining the position of the final passing point P and the preset desired final passing point P0. In comparison, a step for sequentially changing the slope T of the curved surface so that the position of the final pass point P matches the position of the desired final pass point P0, and when the final pass point P matches the desired final pass point P0, Determining the slope T of the surface as the slope of the desired refraction surface at the intersection PT;
By sequentially changing the height h or the angle with respect to the optical axis L, the intersection P of a curved surface that is continuous with the set curved surface whose inclination has been determined.
Calculating T 'and changing the slope T' of the curved surface; and, when the final passing point P 'coincides with the desired final passing point P0', the slope T 'of the curved surface is converted to the desired refracted curved surface at the intersection PT'. Determining the inclination, calculating the shape of the curved surface from the inclination T of the refraction surface at each intersection PT thus repeatedly determined, and manufacturing a lens based on the individually determined shape of the curved surface. And a method of manufacturing an aspherical lens. 2. An aspheric lens manufacturing apparatus using a ray tracing method, wherein ray tracing is performed for a certain incident light ray R,
Intersection position determining means 15 for finding the position of the intersection PT between the ray R and the refraction curved surface, and target value setting means 13 for setting a desired final passing point P0 through which the ray R passing through the intersection PT refracts the final refraction surface. And a slope determining means 14 for appropriately determining the slope T of the curved surface at the intersection PT, and a final passage point calculating means for determining a final passing point P of the ray R corresponding to the slope T of the curved surface determined by the slope determining means. 16 and the final passing point P and the position of the preset desired final passing point P0 are compared, and the position of the final passing point P and the desired final passing point P0 is adjusted so that the position of the curved surface of the inclination determining means is coincident. The slope T is sequentially changed, and the final passing point P
Means 17 for determining the inclination T of the curved surface as the inclination of the desired refraction curved surface at the intersection PT when the target coincides with the desired final passing point P0.
And an initial value setting means 11 for sequentially changing the height h or angle of the incident ray R with respect to the optical axis L, and an intersection PT 'of a curved surface continuous with the set curved surface whose inclination has been determined is obtained. By changing PT ′ and the slope T ′ of the curved surface to make the final pass point P ′ coincide with the desired final pass point P0 ′, the slope of the refraction curved surface is determined.
A curved surface shape calculating means 18 for calculating the shape of the curved surface from the inclination T of the curved surface at the position of, and a storage device 5 for storing the curved surface shape calculated by the curved surface shape calculating device 18. 5. An apparatus for manufacturing an aspherical lens, wherein a lens can be manufactured using the numerical controller 6 based on the information of No. 5.