Method and device for detecting the edge of an object

Patent metadata

Field	Value
Publication number	US-11906284-B2
Application number	US-202117181223-A
Country	US
Kind code	B2
Filing date	Feb 22, 2021
Priority date	Feb 25, 2020
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A method for detecting an edge of an object is carried out by means of a detection device (10), which has an emission region running along a first straight line and has a receiving region which runs along a second straight line, which is arranged in parallel to the first straight line. An emission subregion (11a-p) of the emission region is selected, which extends up to a first end of the emission region. Light is emitted from the emission subregion (11a-p) and a light signal of light reflected on the object is received in the receiving region. The emission subregion (11a-p) is then shifted along the first straight line in the direction of a second end of the emission region. Emitting, receiving and shifting are repeated until the emission subregion (11a-p) extends up to the second end at the start of the shifting step. A signal course is compiled from the received light signals, and the detection of the edge from the signal course is carried out.

First claim

The invention claimed is:

1. Method for detecting ( 48 ) an edge ( 21 ) of an object ( 20 ) by means of a detection device ( 10 ) comprising a micro controller for compiling a signal course and storing signals to determine a threshold value edge point of the object, an emission region ( 11 ) running along a first straight line (G 1 ) and a receiving region ( 13 ) running along a second straight line (G 2 ) in a plane arranged parallel to the first straight line (G 1 ) in a plane, wherein, the emission region ( 11 ) includes a plurality of emission subregions ( 11 a - p , 11 A-O) each emission subregion including at least one light source;
wherein, the receiving region ( 13 ) includes a plurality of receiving subregions ( 13 a - p , 13 A- 0 );
the method comprising:
a) selecting ( 41 ) an emission subregion ( 11 a - p , 11 A-O) of the emission region ( 11 ), wherein the selected emission subregion ( 11 a - p , 11 A-O) has a length along the first straight line (G 1 ) and extends up to a first end of the emission region ( 11 );
b) forming a common sector by selecting a receiving subregion ( 13 a - p , 13 A-O) adjacent and parallel to the selected emission subregion ( 11 a - p , 11 A-O), wherein the selected receiving subregion ( 13 a - p , 13 A-O) has a length along the second straight line (G 2 ) equal to the length of the emission subregion ( 11 a - p , 11 A- 0 ) along the first straight line (G 1 ),
c) emitting ( 42 ) light ( 30 ) from the selected emission subregion ( 11 a - p , 11 A-O),
d) receiving ( 43 ) a light signal (I) of light ( 30 ) reflected on the object ( 20 ) only in the selected receiving subregion ( 13 a - p , 13 A-O) and storing the light signal,
e) shifting ( 45 ) the selected emission subregion ( 11 a - p , 11 A-O) along the first straight line (G 1 ) in the direction of a second end of the emission region ( 11 ) and shifting ( 46 ) the selected receiving subregion ( 13 a - p , 13 A-O) along the second straight line (G 2 ) from a first end in the direction of a second end of the second straight line (G 2 ), wherein when the shifted selected emission subregion is activated, the shifted selected receiving subregion in the common sector is simultaneously activated,
f) repeating steps c to e until the emission subregion ( 11 a - p , 11 A-O) extends up to the second end at the start of step e,
g) compiling ( 47 ) a signal course from the light signals (I) received in step d, and
h) carrying out the detection ( 48 ) of the edge ( 21 ) from the signal course.

2. Method according to claim 1 , characterized in that the emission subregion ( 11 a - p ) contains a light source ( 12 a - p ) and is respectively shifted around a light source ( 12 a - p ) in step e.

3. Method according to claim 1 , characterised in that the emission subregion ( 11 A-O) contains several light sources ( 12 a - p ) and is respectively shifted around a light source ( 12 a - p ) in step e.

4. Method according to claim 1 , characterised in that the receiving region ( 13 ) and the emission region ( 11 ) are separated by an opaque separating element ( 15 ), which is arranged in parallel to the two straight lines (G 1 , G 2 ) and is orthogonal to the plane in which the two straight lines (G 1 , G 2 ) run.

5. Method according to claim 1 , characterised in that the detection ( 48 ) of the edge ( 21 ) is carried out in step h from a flank in the signal course.

6. Method according to claim 5 , characterised in that, during the detection ( 48 ), a nonlinearity of a connection between a position of the flank and a position of the edge ( 21 ) is compensated for.

7. A detection device having a micro controller for compiling signal course and storing signals to determine a threshold value edge point for detection ( 48 ) of an edge of an object, the detecting device comprises:
a circuit board comprising:
an emission region having a plurality of light sources arranged along a first straight line in a plane at equal distances apart and having a length extending up to a first end of the emission region,
a receiving region having a plurality of individual readable photodiode regions, the receiving region running adjacent and parallel to the emission region along a second straight line in the plane,
a common sector formed by at least one emission subregion being selected from the emission region and extending up to the end of the emission region and an adjacent parallel at least one receiving subregion being selected from the receiving region, when the at least one emission subregion is activated in the common sector, the receiving subregion in the common sector is simultaneously activated,
the at least one emission subregion having at least one light source, the receiving subregion receives a reflected light from the object as a light signal,
an opaque separator located in a recess on the circuit board,
a multiplex chip located on the circuit board being adapted to control the light sources in the emission subregion and to transmit light from the emission subregions.

8. Method for detecting an edge of a silicon wafer by means of a detection device having no lens and sized for inclusion in a blade of a transport system, the detection device comprising a micro controller for compiling a signal course and storing signals to determine a threshold value edge point of the silicon wafer, a frame having a recess defining a plane, an emission region running along a first straight line in the plane and a receiving region running along a second straight line in the plane and arranged parallel to the first straight line, the frame further having a divider arranged orthogonal to the plane and separating the emission region and the receiving region and:
wherein, the emission region includes a plurality of emission subregions each emission subregion including at least one light source;
wherein, the receiving region includes a plurality of receiving subregions;

the method comprising:
a) selecting an emission subregion of the emission region, wherein the selected emission subregion has a length along the first straight line in the plane and extends up to a first end of the emission region in the plane;
b) forming a common sector selecting a receiving subregion adjacent and parallel to the selected emission subregion, wherein the selected receiving subregion has a length along the second straight line equal to the length of the emission subregion along the first straight line,
c) emitting light from the selected emission subregion,
d) receiving a light signal of light reflected on the object only in the selected receiving subregion and storing the light signal,
e) shifting the selected emission subregion along the first straight line in the direction of a second end of the emission region and shifting the selected receiving subregion along the second straight line from a first end in the direction of a second end of the second straight line, simultaneously activating the emission subregion and the receiving subregion in the common sector,
f) repeating steps c to e until the emission subregion extends up to the second end at the start of step e,
g) after step f, compiling a signal course from the light signals received in step d, and
h) carrying out the detection of the edge of the silicon wafer from the signal course.

Assignees

• Balluff Gmbh

Inventors

• Schroffenegger Juri
• Hense Sergej

Classifications

• G01B11/14 Primary

  for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00) · CPC title

• G01B11/024

  by means of diode-array scanning · CPC title

• G01B11/028

  by measuring lateral position of a boundary of the object (G01B11/022, G01B11/024, G01B11/04 take precedence) · CPC title

• G01S17/04

  Systems determining the presence of a target · CPC title

• G01V8/20

  using multiple transmitters or receivers · CPC title