Optical device, lens and optical element for focusing a laser beam and apparatus and method for assembling the optical device

Optical device for focusing a laser beam, said device comprising:

• a focusing lens upon which the laser beam is directed;
• means for allowing the optical alignment between the focusing lens and a source of emission of said laser beam;
• and
• first means for selecting only a central portion of the laser beam;
• wherein said first means is directly applied on the focusing lens and defines on the focusing lens an aperture;
• wherein the means for allowing the optical alignment between the source of emission and the focusing lens comprises a substantially tubular portion of lens which extends from a front surface of the focusing lens and is adapted to be mounted by interference on a support structure of the source of emission, said substantially tubular portion comprising an inner wall provided with at least one tooth extended in a substantially radial direction and adapted to be housed into a corresponding housing obtained on the support structure of the source of emission.

Optical device for focusing a laser beam, said device comprising:

• a focusing lens upon which the laser beam is directed;
• means for allowing the optical alignment between the focusing lens and a source of emission of said laser beam;
• and
• first means for selecting only a central portion of the laser beam;
• wherein said first means is directly applied on the focusing lens and defines on the focusing lens an aperture;
• wherein the means for allowing the optical alignment between the source of emission and the focusing lens comprises at least two strips which extend from a front surface of the lens and are adapted to be mounted by interference on a support structure of the source of emission.

Optical device for focusing a laser beam, said device comprising:

• a focusing lens upon which the laser beam is directed;
• means for allowing the optical alignment between the focusing lens and a source of emission of said laser beam;
• and
• first means for selecting only a central portion of the laser beam;
• wherein said first means is directly applied on the focusing lens and defines on the focusing lens an aperture;
• wherein the means for allowing the optical alignment between the source of emission and the focusing lens comprise a substantially tubular container adapted to house the focusing lens and the source of emission;
• and
• wherein the focusing lens comprises a reference notch intended for being positioned in alignment with a visual reference marked on the container.

Optical device for focusing a laser beam, said device comprising:

• a focusing lens upon which the laser beam is directed;
• means for allowing the optical alignment between the focusing lens and a source of emission of said laser beam;
• and
• first means for selecting only a central portion of the laser beam;
• wherein said first means is directly applied on the focusing lens and defines on the focusing lens an aperture;
• wherein the means for allowing the optical alignment between the source of emission and the focusing lens comprise a substantially tubular container adapted to house the focusing lens and the source of emission;
• and
• wherein the container comprises an internal guide adapted to cooperate with an alignment slot formed on the focusing lens.

Optical device for focusing a laser beam, said device comprising a single optical element upon which the laser beam is directed, said single optical element comprising:

• a focusing lens in a central portion of the optical element;
• and
• first means in a surrounding portion of the optical element and around an outer edge of the focusing lens, adapted to separate a central portion of the laser beam from a surrounding portion of the laser beam, said first means and said focusing lens being distinct from one another and being arranged in said single optical element such that they are never adjacent along any direction of propagation of the laser beam within the single optical element;
• wherein the entire portion of the laser beam collected by the focusing lens is focused.

Optical device for focusing a laser beam, said device comprising a single optical element upon which the laser beam is directed, said single optical element comprising:

• a focusing lens in a central portion of the optical element;
• and
• first means in a surrounding portion of the optical element and around an outer edge of the focusing lens, adapted to separate a central portion of the laser beam from a surrounding portion of the laser beam;
• wherein the entire central portion of the laser beam collected by the focusing lens is focused;
• and
• wherein the device is adapted to be used with a device for reading an optical code by means of said laser beam along at least one fixed reading direction, and wherein the first means defines on the focusing lens an aperture having a Fresnel number which is smaller than 2 along the fixed reading direction.

Apparatus for assembling an optical device for focusing a laser beam, said optical device being adapted to be used with a device for reading an optical code by means of said laser beam along at least one fixed reading direction, the optical device comprising:

• a focusing lens upon which the laser beam is directed;
• and
• first means for selecting only a central portion of the laser beam;
• wherein said first means is directly and integrally applied on the focusing lens and defines on the focusing lens an aperture having a Fresnel number which is smaller than 2 along, said fixed reading direction, said optical device further comprising means for allowing optical alignment between the focusing lens and a source of emission of said laser beam, wherein the means for allowing the optical alignment between the source of emission and the focusing lens comprises a substantially tubular container adapted to house the focusing lens and the source of emission,
• wherein said apparatus comprises a support frame for the container and substantially automatic displacement means acting on the source of emission to position the source of emission inside the container.

Method for assembling an optical device adapted to be used with a device for reading an optical code by means of said laser beam along at least one fixed reading direction, the optical device comprising:

• a focusing lens upon which the laser beam is directed;
• and
• first means for selecting only a central portion of the laser beam;
• wherein said first means is directly and integrally applied on the focusing lens and defies on the focusing lens an aperture having a Fresnel number which is smaller than 2 along said fixed reading direction, said optical device further comprising means for allowing optical alignment between the focusing lens and a source of emission of said laser beam, wherein the means for allowing the optical alignment between the source of emission and focusing lens comprise a substanially tubular container adapted to house the focusing lens and the source of emission, said method comprising the steps;
• inserting the focusing lens inside the container using displacement means;
• observing an image of a spot caught by a sensor located at a fixed distance from the container, as a laser diode is inserted in the container;
• stopping displacement of the laser diode when the image of the spot observed presents predetermined dimensions and shape;
• and
• fixing the laser diode into position.

Optical device for focusing a laser beam, said device comprising a single optical element upon which the laser beam is directed, said single optical element comprising;

• a focusing lens;
• and
• first means arranged around an outer edge of the focusing lens, adapted to separate a central portion of the laser beam from a surrounding portion of the laser beam;
• wherein the entire portion of the laser beam collected by the focusing lens is focused.