Precision Freeform Structuring for the Fabrication of Coded Lenses

Patent metadata

Field	Value
Publication number	US-2022355387-A1
Application number	US-202217729915-A
Country	US
Kind code	A1
Filing date	Apr 26, 2022
Priority date	Apr 27, 2021
Publication date	Nov 10, 2022
Grant date	—

Abstract

A system for fabricating coded lenses includes a cutting tool configured to controllably cut a workpiece at a specified position-dependent depth while traversing a surface of the workpiece along a specified two-dimensional path. A signal generator is operative to generate a signal for controlling fabrication of a coded lens from the workpiece. A vibration tool is operative to ultrasonically vibrate the cutting tool for cutting of gratings on the workpiece.

First claim

What is claimed is:

1 . A system for fabricating coded lenses comprising:
a cutting tool configured to controllably cut a workpiece at a specified position-dependent depth while traversing a surface of the workpiece along a specified two-dimensional path; a signal generator operative to generate a signal for controlling fabrication of a coded lens from the workpiece; and a vibration tool operative to ultrasonically vibrate the cutting tool for cutting of gratings on the workpiece.

2 . The system of claim 1 , wherein the cutting tool is configured to machine a freeform surface and fabricate a variable grating on the machined freeform surface.

3 . The system of claim 1 , wherein the cutting tool is configured to rotate to cut the workpiece in directions that are perpendicular to local gradients on the workpiece.

4 . The system of claim 1 , further comprising a vacuum to remove cut material from the cutting tool while the cutting tool is cutting the workpiece.

5 . The system of claim 1 , further comprising a mechanism to feed the workpiece linearly along an axis relative to the cutting tool while the cutting tool cuts the workpiece.

6 . The system of claim 1 , further comprising a spindle operative to hold the workpiece and turn the workpiece about a central axis to facilitate the cutting tool to cut the workpiece while the workpiece is turning.

7 . The system of claim 1 , wherein the vibration tool includes an elliptical vibration tool.

8 . A method for fabricating coded lenses comprising:
generating a signal for controlling fabrication of a coded lens from a workpiece; causing a cutting tool to traverse a surface of the workpiece along a specified two-dimensional path, based on the signal; controllably cutting a workpiece at a specified position-dependent depth while traversing the surface of the workpiece along the specified two-dimensional path, based on the signal; and ultrasonically vibrating the cutting tool for cutting gratings on the workpiece.

9 . The method of claim 8 , further comprising computing a three-dimensional freeform surface for machining a freeform lens from the workpiece, wherein computing the three-dimensional freeform surface is based on a Chebyshev polynomial

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indicates text missing or illegible when filed

where x, y, z are global coordinates; X, Y, Z are workpiece coordinates; ρ, θ are workpiece polar coordinates; φ is spindle angular position; Z=f z (X,Y) is the freeform surface function; Z 0 is the reference depth; T i (x) is the i th order Chebyshev polynomials at x; C ij is the 2-D Chebyshev polynomials coefficient; i, j are the order of Chebyshev polynomials; I, J are the maximum order of Chebyshev polynomials; c is the curvature of toric ter

Assignees

• Univ Northwestern

Inventors

• Guo Ping
• Wang Yaoke

Classifications

• B23B2220/126

  Producing ring grooves · CPC title

• B23B5/36 Primary

  for turning specially-shaped surfaces by making use of relative movement of the tool and work produced by geometrical mechanisms, i.e. forming-lathes · CPC title

• B23B25/02

  Arrangements for chip-breaking in turning-machines (on cutting tools B23B27/22) · CPC title

• B23B2226/45

  Glass · CPC title

• B23B2270/62

  Use of suction · CPC title