Apparatus and process for focusing a laser beam for reading optical codes

Claim 2

A laser beam focusing apparatus for reading optical codes on objects carried on a supporting plane which is provided with a means for moving the objects along a feeding direction, comprising: a laser beam scanner, which scanner is positioned relative to the object supporting plane so as to illuminate the object surface bearing the optical code; a data processing unit connected to the scanner; a first scan means for generating at least a first scan in a first scan plane, so as to measure only an instantaneous distance of at least one point on the surface of each of said objects from the scanner; a second scan means for generating a plurality of second scans in a second scan plane, different from the first one, so as to read the optical code on the object; and a means for focusing the laser beam lying on the second scan plane according to the measured distance value.

Claim 3

An apparatus according to claim 1 , wherein the laser beam scanner emits modulated light.

Claim 4

An apparatus according to claim 1 , wherein the second scan plane is different from the first scan plane.

Claim 5

An apparatus according to claim 1 , wherein the first scan plane intercepts the object in advance of the second scan plane, relative to the movement of the object on the supporting plane along the feeding direction.

Claim 6

An apparatus according to claim 1 , wherein the first and second scan planes are inclined to each other at an angle of inclination within a range of 2° to 20°.

Claim 7

An apparatus according to claim 5 , wherein the inclination angle between the scan planes is approximately 6°.

Claim 8

An apparatus according to claim 1 , wherein the first scan means is activated in advance of the second scan means.

Claim 9

An apparatus according to claim 1 , comprising a polygonal mirror-carrying rotor, wherein the first scan means comprises some (m) of the rotor mirrors and the second scan means comprises the remaining (n-m) rotor mirrors, said some of the rotor mirrors having a different inclination angle from the rotor axis than that of said remaining rotor mirrors.

Claim 10

An apparatus according to claim 8 , wherein said some of the rotor mirrors are a single mirror.

Claim 11

An apparatus according to claim 1 , comprising a polygonal mirror-carrying rotor, wherein the first scan means comprises a plurality of first rotor mirrors mounted around a first peripheral portion of the rotor, and the second scan means comprises a plurality of second rotor mirrors mounted around a second peripheral portion of the rotor adjacent to said first peripheral portion, the mirrors of said plurality of first mirrors having a different inclination angle from the rotor axis than that of the mirrors of said plurality of second mirrors.

Claim 12

An apparatus according to claim 1 , comprising an oscillating mirror having an oscillation plane movable between two different positions.

Claim 13

An apparatus according to claim 1 , comprising a modulated light laser source housed within the scanner and oscillating in a movable plane between two different positions.

Claim 14

A process for focusing a laser beam for reading optical codes on objects which are carried on a supporting plane provided with a means for moving the objects along a feeding direction, comprising the following steps: a) defining a first scan plane intersecting the supporting plane along a first scan line, said first plane comprising at least one laser beam; b) defining a second scan plane, different from the first scan plane, intersecting the supporting plane along a second scan line, said second plane comprising at least one laser beam; c) performing at least a first scan across the surface of one of said objects by means of the laser beam lying on the first scan plane for measuring only an instantaneous distance of at least one point on the surface of said object from a scanner emitting said laser beams; d) processing the data provided by said first scan and calculating the measured distance value; and e) focusing the laser beam lying on the second scan plane according to the calculated distance value.

Claim 15

A process for focusing a laser beam for reading optical codes on objects which are carried on a supporting plane provided with a means for moving the objects along a feeding direction, comprising the following steps: a) defining a first scan plane intersecting the supporting plane along a first scan line, said first plane comprising at least one laser beam; b) defining a second scan plane, different from the first scan plane, intersecting the supporting plane along a second scan line, said second plane comprising at least one laser beam; c) performing at least a first scan across the surface of one of said objects by means of the laser beam lying on the first scan plane for measuring only an instantaneous distance of at least one point on the surface of said object from a scanner emitting said laser beams; d) processing the data provided by said first scan and calculating the measured distance value; and e) focusing the laser beam lying on the second scan plane according to the calculated distance value.

Claim 16

A process according to claim 13 , wherein the laser beam laying on the first scan plane is a modulated light laser beam.

Claim 17

A process according to claim 13 , further comprising the following steps: f) performing a plurality of scans across the object by means of the laser beam lying on the second scan plane; g) processing the data provided by said plurality of scans so as to read the optical code.

Claim 18

A process according to claim 13 , wherein the first scan plane intercepts the object in advance of the second scan plane, relative to the movement of the object on the supporting plane along the feeding direction.

Claim 19

A process according to claim 16 , wherein the inclination angle between the scan planes is approximately 6°.

Claim 20

A process according to claim 13 , wherein the first and second scan planes are inclined to each other at an angle of inclination within an range of 2° to 20°.

Claim 21

A process according to claim 13 , wherein said first and second scans are performed by means of a single polygonal mirror-carrying rotor, wherein the first scan means comprises some (m) of the rotor mirrors, and wherein the second scan means comprises the remaining (n-m) rotor mirrors, said some of the rotor mirrors having a different inclination angle from the rotor axis than that of said remaining rotor mirrors.

Claim 22

A process according to claim 13 , wherein said first and second scans are performed by means of a single polygonal mirror-carrying rotor, wherein the first scan means comprises a plurality of first rotor mirrors mounted around a first peripheral portion of the rotor, and wherein the second scan means comprises a plurality of second rotor mirrors mounted around a second peripheral portion of the rotor adjacent to said first peripheral portion, the mirrors of said plurality of first mirrors having a different inclination angle from the rotor axis than that of the mirrors of said plurality of second mirrors.

Claim 23

A process according to claim 20 , wherein said some of the rotor mirrors are a single mirror.

Claim 24

A process according to claim 13 , wherein said first and second scans are performed by means of an oscillating mirror having an oscillation plane movable between two different positions.

Claim 25

A process according to claim 13 , wherein said first and second scans are performed by means of a laser source housed within the scanner and oscillating in a movable plane between two different positions.