Method and device for the three-dimensional determination and digitisation of a plaster-or positive-model

• US 20040151367A1
• Filed: 12/19/2003
• Published: 08/05/2004
• Est. Priority Date: 07/13/2001
• Status: Active Grant

• Current Assignee: Degudent GmbH
• Original Assignee: Degudent GmbH
• Inventors: Fecher, Stefan, Wolf, Dietrich
• Granted Patent: US 7,596,287 B2
• Time in Patent Office: Days
• US Class Current: 382/154
• CPC Class Codes: A61C 13/0004 Computer-assisted sizing or machining of dental prostheses
• CPC Class Codes: A61C 13/0009 using a copying machine
• CPC Class Codes: A61C 5/77 Methods or devices for making crowns
• CPC Class Codes: A61C 9/0053 Optical means or methods, e.g. scanning the teeth by a laser or light beam
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns

Abstract

The invention relates to a method for the three-dimensional determination and digitisation of a plaster- or positive-model (1), in particular for the production of replacement teeth, whereby a method with improved handling and costs and with the following steps is disclosed: clamping the plaster- or positive-model (1) in a mounting (2) with a defined orientation, irradiation of the plaster- or positive-model (1), by means of a radiation source and recording of the radiation reflected by the plaster- or positive-model (1), evaluation of the reflected radiation by a scanning unit (7) and generation of separation information, defined movement of the plaster- or positive-model (1) relative to the radiation source along an axis (y), approximately perpendicular to the direction of radiation and linking the displacement with the separation information. The invention also relates to a device for carrying out said method.

Claims

1. Method for the three-dimensional mapping and digitization of a plaster or positive model (1), in particular for producing a dental prosthesis, with the following steps:

clamping the plaster or positive model (1) in a mounting (2) which is rotatable about an axis of rotation in a defined orientation;

irradiation of the plaster or positive model (1) by means of a radiation source and receiving the radiation reflected by the plaster or positive model (1);

evaluating the reflected radiation by a scanning unit (7) and generating a distance information;

defined movement of the plaster or positive model (1) relative to the radiation source along a plane and/or first axis (y) which extends perpendicular or almost perpendicular to the direction of radiation;

linking a signal for detection of the rotation with the path and distance information for forming a three-dimensional volume model of the plaster or positive model (1), whereby the distance between the mounting (2) and scanning unit (7) in direction of the optical axis (z axis) of the scanning unit (7) remains unchanged or essentially unchanged during the digitization of the plaster or positive model (1) along a scanning path s, where s≧

1 mm.

2. Method according to claim 1,

characterized in that

the distance between the mounting (2) and the scanning unit (7) along the entire or almost entire scanning path s of a side of the plaster or positive model is constant.

3. Method according to claim 1,

characterized in that,

to determine and digitalize the positive model, it is turned through 180°

or approximately 180°

about the axis of rotation of the mounting which extends perpendicular to the direction of radiation.

4. Method according to at least one of the preceding claims,

characterized in that

the radiation takes place by a line scanner.

5. Method according to at least one of the preceding claims,

characterized in that

the radiation takes place by a laser beam with almost point-like beams.

6. Method according to at least claim 1, further characterized by the following steps:

defined movement of the body (1) relative to the radiation source along a second axis (x) extending perpendicular or almost perpendicular to the first axis (y) perpendicular to or almost perpendicular to the direction of radiation; and

linking the second travel path with the distance information and the first travel path.

7. Method according to at least one of the preceding claims, further characterized by the following step:

standardizing the distance information to a reference point of the plaster or positive model (1).

8. Method according to claim 7,

characterized in that

the reference point is almost that point of the plaster or positive model (1) which delivers the lowest distance value.

9. Method according to claim 7 or 8,

characterized in that

the reference point is determined by a preliminary run-through of the method.

10. Device for carrying out a method according to one of the preceding claims, having a mounting (7) to accommodate a plaster or positive model (1) to be mapped and digitalized, a scanning unit (7) for optically scanning the plaster or positive model (1), wherein the mounting (1) with the plaster or positive model (1) can be moved in at least one direction (y) relative and at a right angle or almost at a right angle to the optical axis of the scanning unit (7), and a device for detecting the path of the mounting (2) with the plaster or positive model (1) which is rotatable perpendicular to the optical axis through at least 180°

or almost 180°

in the at least one direction (y), wherein the scanning unit (7) comprises a CCD image recorder, a birefractive crystal and an objective in the ray path.

11. Device according to claim 10,

characterized in that

the scanning unit also comprises a laser diode as well as a device for reflecting the light of the laser diode into the ray path of the scanning unit (7).