Hommelwerke Gmbh

Gerd Ulbers

Karl Hutter

Optical retro-reflector in particular for purposes of interferometry. It has the form of a sphere and is fashioned from an optically refractive material, the index of refraction of which is at least approximately 2, but by preference precisely 2. The reflecting surface of the sphere is coated with a film of reflecting material, preferably vapor-deposited metal. The retro-reflector can be manufactured cheaply and with a high level of surface quality. It has a high degree of reflecting power.

Optical retro-reflector

A laser optical apparatus for measuring the distance between the apparatus and a measuring surface which comprises an optical measuring reflector on said measuring surface, a converting transformer for converting the position of said reflector into corresponding electrical signals and an indicator for said signals. The improvement comprises a first optical interferometer having a measuring wave guide coupled with a reference wave guide and a second optical interferometer also having measuring and reference wave guides. The length of the second measuring wave guide is different from the length of the second reference wave guide and a computer is used to compare output electrical signals the value of which depend upon this difference. The apparatus also includes a device to correct the wave length of the laser beam by controlling the electrical current to the laser.

Device for measuring the distance between the device and a measuring

A device for measuring the distance between the device and a measuring surface, with an optical interferometer, which has a measuring wave guide, one end of which is connected with a laser and the other of which is directed to optical measuring reflector which is positioned on the measuring surface or is connected with the same in an effective manner, which reflects the light back into the measuring wave guide. The interferometer furthermore has a reference wave guide which is coupled with the measuring wave guide at a coupling point, has a mirror on its one end, and on its other end, a photoelectrical converter, which is connected with an indicator device for indicating the electrical output signal of the photoelectrical converter. The reference wave guide is coupled, preferably by means of a polarizing beam splitter, with a branch wave guide, the end of which is connected with an additional photoelectrical converter. The reference wave guide has a phase adjustment device. The outputs of the photoelectrical converter are connected with a differential amplifier, the output signal of which is free from direct current and, is fed into the indicator device. Because the output signal of the differential is free from direct current, the further processing of the interference output signal is facilitated and the measuring precision is increased.

Distance measuring device

Device for the contact-free measurement of a distance from a surface, particularly for scanning the contour of a surface of a workpiece along a given measuring path, comprising a measuring body enclosing optoelectronic means for transmitting light to the surface to be measured and converting the light reflected by such surface into an electrical signal as a function of the distance from the surface. The measuring body is supported on a stand and is movable in the direction of measurement. The optoelectronic means comprise a focus position measuring system and an optoelectronic position scanning unit for scanning the position of the measuring body relative to the supporting stand. An adder connected to indicating or recording means adds the output signal of the focus position measuring system to the output signal of the position scanning unit to produce a summation signal which corresponds to the distance of the measuring body from the surface being measured at any selected point of movement of the measuring body on the supporting stand. Thus, the measured value is additively formed of two partial values, of which the partial value derived from the focus position measuring system is obtained without sluggishness, while the other partial value permits the measurement of a coarse profile.

Device for scanning the contour of a surface of a workpiece

A device for measuring small distances, provided with a sensing tip mounted to be movable in the direction of the length to be measured, a transducer for converting the movements of the sensing tip into corresponding electric signals, and indicating means to indicate such signals. The transducer comprises an optical interferometer provided with a measuring waveguide. One end of the waveguide is connected to a laser and the other end to optical means for directing the light onto a measuring mirror disposed at a distance. The light is reflected by the mirror back to the optical means. The measuring mirror is connected to the sensing tip. The interferometer further includes a reference waveguide linked to the measuring waveguide. The reference waveguide has a mirror disposed at one end and a photoelectric transduer at the other end. The transducer is connected to the indicating means for indicating the output signals of the transducer. The device permits a cost-effective and uncomplicated construction as an integrated unit. The device affords precision measurements at accuracies in the range of one half of the wavelength of the lasr beam, or even far below such a value. The device also exhibits a high linearity for substantially greater distances. The device is also suitable for measuring extremely rapid changes in length while using a small bearing pressure on the sensing tip.

Device for measuring small distances

A device for measuring small distances, provided with a sensing tip mounted to be movable in the direction of the length to be measured, a transducer for converting the movements of the sensing tip into corresponding electric signals, and indicating means to indicate such signals. The transducer comprises an optical interferometer provided with a measuring waveguide. One end of the waveguide is connected to a laser and the other end to optical means for directing the light onto a measuring mirror disposed at a distance. The light is reflected by the mirror back to the optical means. The measuring mirror is connected to the sensing tip. The interferometer further includes a reference waveguide linked to the measuring waveguide. The reference waveguide has a mirror disposed at one end and a photoelectric transducer at the other end. The transducer is connected to the indicating means for indicating the output signals of the transducer. The device permits a cost-effective and uncomplicated construction as an integrated unit. The device affords precision measurements at accuracies in the range of one half of the wavelength of the laser beam, or even far below such a value. The device also exhibits a high linearity for substantially greater distances. The device is also suitable for measuring extremely rapid changes in length while using a small bearing pressure on the sensing tip.

Growing community of inventors

Weilersbach, Germany

Gerd Ulbers