US-12623301-B2 - Warm-up target for a laser engraver

US12623301B2US 12623301 B2US12623301 B2US 12623301B2US-12623301-B2

Abstract

A laser marking system comprises a laser energy source that generates a laser beam, a laser controller configured to focus the laser beam over a field of view greater than a size of laser-markable items, and a start-up target that includes laser-safe material and is located within the field of view. The laser controller is further configured to point the laser beam at the start-up target during a start-up phase of the laser energy source and focus the laser beam on one of the laser-markable items after the start-up phase.

Inventors

Michael Jon Woizeschke
Timothy Joel Wolf

Assignees

ASSA ABLOY AB

Dates

Publication Date: 20260512
Application Date: 20210607

Claims (14)

1 . A laser marking system for marking laser-markable items, the system comprising: a laser energy source configured to generate a laser beam; a laser controller configured to focus the laser beam over a field of view greater than a size of the laser-markable items; and a start-up target that includes laser-safe material that is safe from laser marking and is located within the field of view; wherein the laser controller is further configured to: point the laser beam at the start-up target during a start-up phase of the laser energy source, wherein energy of the laser beam transitions from an idle state energy to a steady state energy during the start-up phase and the start-up target is positioned away from a focal distance of the laser source used during laser-marking; and focus the laser beam on one of the laser-markable items after the start-up phase.
2 . The system of claim 1 , wherein the start-up target is positioned within the field of view and closer to the laser energy source than a position of the one of the laser-markable items during laser-marking.
3 . The system of claim 1 , wherein the start-up target includes metal having a non-reflective coating.
4 . The system of claim 1 , wherein the laser controller is configured to point the laser beam at the start-up target between marking of each of the laser-markable items.
5 . The system of claim 1 , including: a transport mechanism that positions the laser-markable items in the field of view for marking; and wherein the laser controller is configured to point the laser beam at the start-up target in the field of view during the start-up phase while the one of the laser-markable items is positioned in the field of view.
6 . The system of claim 1 , wherein the laser energy source increases laser energy of the laser beam during the start-up phase.
7 . A method of operating a laser marking system, the method comprising: generating a laser beam using a laser energy source; pointing the laser beam at a laser-safe start-up target that is safe from laser marking and is located in a field of view of the laser energy source during a start-up phase of the laser energy source, wherein energy of the laser beam transitions from an idle state energy to a steady state energy during the start-up phase and during the start-up phase the start-up target is positioned away from a focal distance of the laser source used during laser-marking; and focusing the laser beam after the start-up phase on a laser-markable item positioned in the field of view of the laser energy source.
8 . The method of claim 7 , wherein the start-up target is located closer to the laser energy source than the laser-markable item.
9 . The method of claim 7 , including: marking multiple laser-markable items using the laser beam; and pointing the laser beam at the start-up target after marking a laser-markable item.
10 . The method of claim 7 , including positioning the laser-markable item in the field of view for marking using a transport mechanism, and wherein pointing the laser beam includes pointing the laser beam at the start-up target while positioning the laser-markable item for marking.
11 . The method of claim 7 , including increasing laser energy of the laser beam during the start-up phase.
12 . A card marking system, the system comprising: a laser module including: a laser energy source configured to generate a laser beam; and a laser controller configured to focus the laser beam over a field of view defining an engravable area by the laser beam; a start-up target that includes laser-safe material that is safe from laser marking and is located within the field of view; and a transport mechanism to receive a laser-markable card and position the card within the field of view; wherein the laser controller is further configured to: point the laser beam at the start-up target during a start-up phase of the laser energy source, wherein energy of the laser beam transitions from an idle state energy to a steady state energy during the start-up phase and during the start-up phase the start-up target is positioned away from a focal distance of the laser source used during laser-marking; and focus the laser beam on the laser-markable card after the start-up phase.
13 . The system of claim 12 , wherein the transport mechanism positions the laser-markable card in a plane within the field of view for marking, and the start-up target is positioned above or below the plane of the laser-markable card.
14 . The system of claim 1 , wherein the startup target includes a cavity and a cavity opening; and wherein the laser controller is configured to direct the laser beam into the cavity opening during the start-up phase.

Description

TECHNICAL FIELD Embodiments illustrated and described herein generally relate to engraving systems that use lasers. BACKGROUND Security cards such as identification (ID) cards can be engraved using laser marking systems to add attributes such as images or text data that makes the security cards difficult to forge or manipulate. When a laser first starts up, or has been sitting idle for a time, it can take a while to “warm up” and get the system to be consistent with its burn levels. This can be seen in engraved images as lines that have variable thickness or even missing parts of characters. For example, when lasering the character “E,” the image on the card could be more of an “F” if the lasering starts at the bottom of the character. These types of errors could be even more pronounced when engraving more intricate images. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an illustration of an example of a laser marking system. FIG. 2 is another illustration of the example laser marking system of FIG. 1. FIG. 3 is a cross-sectional illustration showing the field of view of a laser energy source. FIG. 4 is an illustration of an example of a laser start-up target. FIG. 5 is a flow diagram of an example of a method of operating a laser-marking system DETAILED DESCRIPTION When a laser energy source first starts up, or has been sitting idle, it can take time to get the laser beam from the laser source to a steady state. If the laser beam is not at a steady state, images or text produced by the laser beam may not be consistent. Mechanical properties such as heat and electrical properties such as capacitance have a large impact on how a laser-engraved image will look. These issues are more prevalent at the beginning of lasering an image after a longer period of inactivity. During this start-up or warm up time there may be some issues that can show up on an engraved image. The most common issues being consistency in line thickness and consistency in gray tones. Both issues can be cause for reprints due to changes in density in the desired image over a batch of engraved cards. FIG. 1 is an illustration of portions of an example of a laser marking system 100. The system 100 includes a laser module having a laser controller 104 and a laser energy source. The laser energy source generates a laser beam for marking (e.g., engraving) a laser-markable item 106. A lens 102 focuses the laser beam on the laser-markable item. The laser controller 104 may include logic circuitry such as a processor (e.g., a microprocessor, field programmable gate array (FPGA), application specific integrated circuit (ASIC), or other type of processor) to manipulate one or both of the laser energy source and the lens 102. In some examples, the laser module includes a galvanometer optical scanner (galvo), and the laser controller 104 is a galvo controller. In the example of FIG. 1, the laser-markable item is a laser-markable card made from a laser-markable material (e.g., polycarbonate, metal, etc.). For instance, the laser markable item may be an identification card meeting ISO/IEC standard 7810 ID-1 card size format. Although the laser-markable item in the example of FIG. 1 is a rectangular card, the laser-markable item can have other shapes (e.g., a circular badge), and the term “card” encompasses cards of other shapes (e.g., a square card, circular card, etc.) and sizes. The laser-markable item is not limited to cards and may be any item engravable or markable using a laser. The system 100 also includes a transport mechanism. In the example of FIG. 1, the transport mechanism is a belt mechanism that includes belt 108. The transport mechanism moves the laser-markable item 106 to position the laser-markable item 106 in the field of view of the laser for marking. The field of view of the laser defines the maximum area engravable or markable by the laser beam. The laser controller 104 focuses the laser beam over the field of view. The system 100 also includes a start-up target 110 made from a laser-safe material. The laser-safe material may be non-reflective. In certain examples, the start-up target 110 is metal (e.g., a sheet metal tab) with a non-reflective coating (e.g., black zinc plating or other non-reflective paint). The field of view of the laser is greater than the area of the laser-markable item 106 and the start-up target 110 is positioned within the field of view of the laser. In the example of FIG. 1, the start-up target 110 is located farther away from the laser energy source than the laser-markable item 106. Moving the start-up target closer to or farther away from the laser-markable item also moves it out of the optimal focal distance of the laser head, which reduces the energy applied to the start-up target. FIG. 2 is another view of the laser marking system 100 and shows the relative positions of the lens 102, laser controller 104, a laser-markable item 106, belt 108, and start-up target 110. In FIG. 2, the laser-markable item 106 is