CN1971332A - Manufacturing method of aspheric optical element - Google Patents

Abstract

The invention discloses a making method for aspherical optical element that characterized in containing following steps: (1) according to the parameters of the aspherical optical element, the parameters of aspherical tray and sphere slug are determined; (2) the sphere slug is manufactured by the conventional sphere craft, coarse mill the aspherical tray; (3) the sphere slug are mounted on the aspherical tray, heat the slug to softening temperature and keeps temperature for 5 to 25 minutes; (4) cool down to normal temperature; (5) the surface contacting with aspherical tray is manufactured as spherical surface, so it's to say, aspherical optical element with spherical surface and spherical surface is obtained. In the invention the non-contact thermoforming method is adapted to realized the manufacture of aspherical optical element, and reduce the machine difficulty; the obtained aspherical optical elements have high consistency and high surface finish.

Description

A kind of method for making of aspherical optical element

Technical field

The present invention relates to a kind of processing and fabricating method of optical element, be specifically related to a kind of method for making of single face aspherical optical element.

Background technology

Use aspherical optical element in the optical system, can relatively easily correct multiple aberration, thereby obtain better imaging effect than the simple sphere element that uses.One or more non-spherical element can replace a plurality of sphere elements, thereby simplifies apparatus structure, reduces cost and effectively alleviates the instrument volume and weight.

Along with the raising that optical system is required, aspherical optical element has all obtained using widely on dual-use photovoltaic, is widely used in its fibre-optical splice in camera lens, television camera tube, zoom lens, satellite infrared telescope, video recorder camera lens, video recording and recording optical readout head, bar code reading head, optical fiber communication, the Medical Instruments.Cause thus the demand of aspherical optical element is further increased.

In the prior art, common aspherical optical element method for making comprises computer-controlled high precision cutting technology, grinding technique and Ultraprecise polished (grinding) technology of adopting.Ultraprecise polished is the extremely slow a kind of job operation of process velocity, when the surfaceness requirement of part is very high, if adopt the method for forced feed to cut or when carrying out grinding, its form accuracy will directly be subjected to the influence of machine tool feed bearing accuracy, the Ultraprecise polished machining precision that then can obtain to be better than 0.01 μ m.

Remove the finishing method of thickness with single-point control and can make high-precision aspheric surface part, compare with general spherical optics element processing method, this job operation wastes time and energy, and make non-spherical element in this way, the high frequency error on the non-spherical element surface that makes is more much harder than the surface high frequency error of sphere element.In order to produce the low optical aspherical surface element of high frequency error at an easy rate, develop injection moulding and compression molding technology in recent years.Make non-spherical element with these two kinds of method fast, economical ground.The plastic lens injection moulding is that the monomer that will melt injects in the mould, exert pressure on one side, on one side the job operation of cooling curing, this method can be produced in batches at an easy rate, but some problems that plastics itself exist cause the variation of the index of refraction in lens as temperature variation, moisture absorption meeting.

The die forming of glass is the miniaturized component production in enormous quantities method that replaces the best of cutting, grinding, attrition process lens, prism.Moulding technology is that the temperature in the mould is controlled at below the above softening temperature of glass transition temperature of punching press, in mould, enter mobile glass, press molding, and keep this state more than 20 seconds, be evenly distributed up to the glass temperature that has been shaped, obtain the optical element close thus with mould and die accuracy.

Yet, this die forming method, the surface of the aspherical optical element of acquisition contacts with mould, therefore needs high-precision aspheric surface polishing, thereby very difficult and time-consuming when carrying out Mould Machining.

Summary of the invention

It is lower that the object of the invention provides a kind of fabrication process condition requirement, can obtain the method for making of the aspherical optical element of high surface smoothness.

For achieving the above object, the technical solution used in the present invention is: a kind of method for making of aspherical optical element comprises the following steps:

(1), determines the parameter of aspheric surface pallet and sphere blank according to the parameter of the aspherical optical element of need preparations;

(2) adopt conventional sphere technology to make the sphere blank, rough mill the aspheric surface pallet;

(3) the sphere blank is placed on the aspheric surface pallet, be warming up to the softening temperature of blank correspondence, be incubated 5 to 25 minutes;

(4) be cooled to normal temperature;

(5) face that will contact with the aspheric surface pallet is processed as sphere, and promptly obtaining one side is aspheric surface, and another side is the required aspherical optical element of sphere.

In the technique scheme, in the described step (1),, utilize glass elements to change the equal principle of front and back volume and obtain the face type data of sphere blank and the face type data of aspheric surface pallet according to aspheric type requirement of need preparation.The aforementioned calculation stress blank variable quantity minimum in the type process of hoping for success.

Further technical scheme is set one group of sphere roughcast warehouse earlier, according to the face type data of required sphere blank, selects immediate sphere blank in the sphere roughcast warehouse, carries out back substitution then and calculates, and obtains the face type data of aspheric surface pallet.Owing to adopt the sphere blank data in the sphere roughcast warehouse of setting, can further facilitate the making of sphere blank.

Optimized technical scheme is that described aspheric surface pallet adopts ceramic material.For the aspheric surface pallet, should select good permeability in principle for use, thermal deformation is little, thermal behavior is stable, dysgeogenous fire resistive material, generally speaking to adopt high temperature resistant weatherproof stupalith to be advisable.

Because the technique scheme utilization, the present invention compared with prior art has following advantage:

1. the present invention adopts contactless thermoforming process to realize the making of aspherical optical element, need not high-precision aspheric surface milling and grinding machine, also need not high-precision aspheric polishing machine;

2. method of the present invention is different with hot-pressing technique, the aspheric surface face type of hot-pressing technique element contacts with mould, and the aspheric surface face type of the inventive method element does not contact with mould, thereby, its surface smoothness depends on that sphere adds the surface smoothness in man-hour, and is irrelevant with aspheric mould or pallet, greatly reduces difficulty of processing thus, and the fine crack on blank surface convergence automatically at high temperature;

3. because the consistance of sphere blank is controlled easily, make the consistance height of the non-spherical element that obtains;

4. the non-spherical element that obtains of the present invention, surface smoothness is than classic method height, and with the aspherical optical element that this method is made, face shape error p-v is in 5um, and local error is good, and the surface high frequency error is low.

Description of drawings

Accompanying drawing 1 is the structural representation before the embodiment of the invention one distortion;

Accompanying drawing 2 is the structural representation after embodiment one distortion.

Wherein: 1, sphere blank; 2, aspheric surface pallet.

Embodiment

Below in conjunction with drawings and Examples the present invention is further described:

Embodiment one: to shown in the accompanying drawing 2, a kind of method for making of aspherical optical element comprises the following steps: referring to accompanying drawing 1

(1) sets one group of sphere roughcast warehouse earlier, parameter according to the aspherical optical element of need preparations, in making every effort to the thermoforming process on the basis of blank variable quantity minimum, utilize glass elements to change the equal principle of front and back volume and obtain the face type data of desirable sphere blank and the face type data of aspheric surface pallet, in the sphere roughcast warehouse, select immediate sphere blank in view of the above, carry out back substitution then and calculate, obtain the face type data of the aspheric surface pallet of actual employing.

(2) adopt conventional sphere technology to make sphere blank 1, rough mill aspheric surface pallet 2;

(3) sphere blank 1 is placed on the aspheric surface pallet 2, put into the thermoforming stove, temperature in the stove is risen to the softening temperature of chunk glass correspondence, be incubated 5 to 25 minutes;

(4) be cooled to normal temperature, take out semi-manufacture;

(5) face that will contact with the aspheric surface pallet is processed as sphere, and promptly obtaining one side is aspheric surface, and another side is the required aspherical optical element of sphere.

In the present embodiment, described aspheric surface pallet adopts ceramic material.

Embodiment two: a kind of method for making of aspherical optical element, the non-spherical element of present embodiment are the curved month type eyeglass.Its concave surface is an aspheric surface, and its surface description equation is

$Z=\frac{c{x}^2}{1+\sqrt{1-(1+k)c^2{x}^2}}+\underset{i=2}{\overset{8}{\mathrm{\Σ}}}{A}_{{2i}^{X^{2i}}}$

Wherein: z is the rise at x point place, and c=1/R, k are conic constant, A ₂～A ₁₆Be high-order term, the concave surface data are:

c＝0.003945

k＝20.571

A ₄＝1.7233e-005

A ₆＝-9.7003e-008

A ₈＝2.6821e-010

A ₁₀＝-3.9606e-013

A ₁₂＝3.2093e-016

A ₁₄＝-1.3459e-019

A ₁₆＝2.2828e-023

Its convex surface is the sphere of R=145, and thickness is 4.

On the basis of blank variable quantity minimum, utilize glass elements to change the principle that the front and back volume equates in making every effort to the thermoforming process, through calculating, we use the chunk glass of following requirement:

Upper surface (concave surface) radius-of-curvature is: 80, and lower surface (convex surface) radius-of-curvature is: 100, thickness is 8;

Obtain describing the aspheric surface parameter of tray surface simultaneously:

c＝1/120；

k＝0；

A ₄＝+9.25e-7；

A ₆＝-1.322e-10；

A ₈＝+1.38e-13；

A ₁₀＝-4.045e-17；

A ₁₂＝0；

A ₁₄＝0；

A ₁₆＝0；

Adopt conventional sphere technology to make the sphere blank, rough mill the aspheric surface pallet;

The sphere blank is placed on the aspheric surface pallet, put into the thermoforming stove, temperature in the stove is risen to the softening temperature of chunk glass correspondence, be incubated 5 to 25 minutes;

Be cooled to normal temperature, take out semi-manufacture;

The convex surface of R=145 is processed at the back side, and guarantees that thickness is 4, so just obtained the non-spherical element that requires.

Claims (4)

1. the method for making of an aspherical optical element is characterized in that, comprises the following steps:

(1), determines the parameter of aspheric surface pallet and sphere blank according to the parameter of the aspherical optical element of need preparations;

(2) adopt conventional sphere technology to make sphere blank [1], rough mill aspheric surface pallet [2];

(3) sphere blank [1] is placed on the aspheric surface pallet [2], be warming up to the softening temperature of blank correspondence, be incubated 5 to 25 minutes;

(4) be cooled to normal temperature;

(5) face that will contact with the aspheric surface pallet is processed as sphere, and promptly obtaining one side is aspheric surface, and another side is the required aspherical optical element of sphere.

2. the method for making of aspherical optical element according to claim 1, it is characterized in that: in the described step (1), according to aspheric type requirement of need preparation, utilize glass elements to change the equal principle of front and back volume and obtain the face type data of sphere blank and the face type data of aspheric surface pallet.

3. the method for making of aspherical optical element according to claim 2, it is characterized in that: set one group of sphere roughcast warehouse earlier, face type data according to required sphere blank, in the sphere roughcast warehouse, select immediate sphere blank, carry out back substitution then and calculate, obtain the face type data of aspheric surface pallet.

4. the method for making of aspherical optical element according to claim 1 is characterized in that: described aspheric surface pallet employing ceramic material.