3D SHAPE GmbH - A new method to measure specular free-form surfaces

Using our new area type 3D sensor SpecGAGE^3D, specular surfaces like those of eyeglass lenses, car bodies, plastic films, solar cells, hard disks, etc. can be measured quickly and very accurately in a cost efficient manner. This product provides a tool for development and quality assurance departments to improve the production process in order to avoid manufacturing errors and, consequently, to minimize costs.

Further information can be found in the product sheet, available in PDF format.

Measurement Principle

The new sensor is based on the principle of phase measuring deflectometry. To calculate the local slope of a surface a fringe pattern with a sinusoidal profile is projected onto a ground glass. A video camera observes the reflections of this pattern via the surface under test. The local slope of the surface can directly be calculated from the distortions of the observed fringe pattern. The local surface curvature is simply the first derivative of the local slope.

This technique provides crucial advantages when compared with range measuring methods since for curvature computation the data have to be differentiated only once. Thus, high frequency noise is much less amplified than in the case of range data, which have to be differentiated twice.

Sensor Specifications

Measurement Principle

- Phase Measuring Stereo Deflectometry

Field of view

- 80 x 80 mm²

Measuring range

- ±18°

Measurement uncertainty

- ±0.02 dpt

Calibration

- The device is factory calibrated and can be re-calibrated by a technician
on request.

Included in package

- SpacGAGE^3D

- PC

- Control and evaluation software for Microsoft Windows® NT/2000/XP

Dimensions h x w x d

- 1850 x 850 x 750 mm³

Measurement Examples

Example for measuring a progressive eyeglass lens. The local mean surface power (mean curvature) is represented on the left side, the local astigmatism is displayed on the right.

Distributor

Exclusive distribution for ophthalmics by Schneider GmbH & Co KG.

Measuring the surface of a lens with SpecGAGE^3D

Produkte > SpecGAGE3D

A new method to measure specular free-form surfaces

Measurement Principle

Sensor Specifications

Measurement Examples

Distributor

Produkte > SpecGAGE^3D