TW201539328A - Optical mark reader - Google Patents

Abstract

Each data point within a two-dimensional code can be represented by a distribution of spots (32). Each spot (32) can be made small enough to be invisible to the human eye so that the two-dimensional code can be invisible on or within transparent or nontransparent materials. The spots (32) can be spaced at a large distance (s) to increase the signal-to-noise ratio for an optical code reader. A code reader can be adapted to read the spots (32) and determine the data points.

Description

Optical marker reader [Copyright Notice]

©2015 Electro Scientific Industries, Inc. One of the disclosures of this patent document contains material that is subject to copyright protection. The copyright owner does not object to the reproduction or reproduction of any patent document or patent disclosure in the patent file or record of the Patent and Trademark Office, except in all cases. 37 CFR § 1.71(d).

[related application]

This application is a non-provisional application of U.S. Patent Application Serial No. 62/033,989, filed on Aug. 6, 2014, the content of which is hereby One of the U.S. Patent Application Serial No. 14/194,455, filed on Feb. 28, 2014, the entire content of which is hereby incorporated by reference.

This application relates to optical readers and, in particular, to systems and methods for reading optical indicia, such as indicia that are invisible to a human eye.

Two-dimensional identification (2DID) codes (such as Quick Response (QR) codes and GS1 DataMatrix (DM) codes) are widely used for product tracking and provide a type of matrix bar code for various information. The QR code consists of a filled dark square (black square) placed in a square on a light background. And adapted for high speed capture by an imaging device such as a camera. In these codes, each square represents a data point. Typical checkered patterns range from 11 squares to 177 squares per column or row. Acquiring patterns in the horizontal and vertical components of the image can be revealed or activated (such as for business tracking, entertainment and transportation ticketing, product labeling, product marketing, mobile phone labels, coupons, display text, adding electronic card contact information, Open a URL or URI or write a code message for an email or text message. QR codes are covered by an ISO standard and their use is exempt. QR code generation websites and applications are widely available, so users can generate and print their own QR codes for others to scan. (See http://en.wikipedia.org/wiki/QR_code.) An exemplary QR code is shown in Figure 1.

The GS1 DataMatrix code is also covered by several ISO and IEC standards (such as 15424 and 15459) and is exempt from authorization for many applications. See http://en.wikipedia.org/wiki/Data_Matrix. GS1 DataMatrix code generation resources are also widely available. An exemplary GS1 DataMatrix code generated using http://datamatrix.kaywa.com is shown in Figure 2.

There are methods for marking such DM or 2DID codes on a variety of materials and in many different sizes, wherein the entire pattern of 2DID codes is greater than 500 microns ([mu]m). For example, some 2DID codes can be printed on the logo using conventional printing techniques, engraved in metal and engraved in the tombstone.

An optical code reader can be used to read the optical codes from an external surface that supports the optical codes. The write and decode schemes are generally robust and include embedded Cyclic Redundancy Check (CRC) error correction, which ensures data integrity for accurate printing of the code. For example, international standards for writing and decoding certain types of such 2DID codes can be Found at http://www.gs1.org/docs/gsmp/barcodes/GS1_General_Specifications.pdf. However, if the 2DID code contains printing errors or inconsistencies, the 2DID code may be much more difficult to decode (if not impossible).

The Summary is provided to introduce a selection of concepts in the Detailed Description. This Summary is not intended to identify key or essential inventive concepts of the subject matter, or the scope of the subject matter.

In some embodiments, a two-dimensional code is represented by a dot spread on or within a substrate having a contrasting background, wherein the dot spreads a plurality of points including a plurality of groups, the points of the groups including the first and second a point of a group, wherein each of the points of the first and second groups represents a geometric shape such that the points are interspersed to form an array of multiple columns and a plurality of rows of geometric regions, wherein some of the geometric regions comprise a The points of the group and some of the geometric regions are missing points.

In some alternative, additional or cumulative embodiments, a method for marking a substrate with a two-dimensional identification code includes generating a laser pulse and directing the laser pulses at the substrate to form a point on or within the substrate a scatter, wherein the point scatters a point representing the two-dimensional code and includes a plurality of groups, the points of the groups including points of the first group and the second group, wherein the points of the first and second groups are Each represents a geometric shape such that the dots are interspersed to form an array of multiple columns and rows of geometric regions, wherein some of the geometric regions comprise a group of points and some of the geometric regions are missing points.

In some alternative, additional or cumulative embodiments, a laser micromachining system for marking a substrate on or within a substrate of a workpiece using a two-dimensional identification code, wherein the two-dimensional code comprises an array of geometries a region that specifies some of these geometric regions and does not refer to Determining some of the geometrical regions, the laser micromachining system comprising: a laser for generating a laser pulse along a beam axis; a workpiece support system for moving the workpiece; a beam positioning system Operative to direct the beam axis toward the workpiece such that a laser pulse is operable to mark a point on the substrate; and a controller for coordinating relative movement of the workpiece support system and the beam positioning system, And for converting a specified geometrical region of the two-dimensional code to a relative position on the substrate for points representing the groups of the specified geometric regions.

In some alternative, additional or cumulative embodiments, a method for reading a two-dimensional identification code in a substrate having one of the first and second opposing surfaces includes directing light toward a first surface of the substrate Wherein the light has a wavelength and wherein the substrate is transparent to the wavelength, wherein the two-dimensional code is represented by a dot spread in the substrate, wherein the dot spreads a plurality of points including a group, the points of the group include a point of a first group and a second group, wherein each of the points of the first and second groups represents a geometric shape such that the points are dispersed to form an array of multiple columns and a plurality of rows of geometric regions, wherein the geometric regions Some of the points comprising a group and some of the geometric regions are missing points, wherein a first portion of the light is blocked by the points, and wherein a second portion of the light passes beyond the points and propagates through the a second surface of the substrate; amplifying the second portion of the light that propagates through the second surface of the substrate; utilizing an imager to propagate through the second surface of the substrate and amplifying the second portion of the light Imaging; analyzing the light One image and the second portion of the barrier by the light of the first portion of shading due to determine the spread of such points; and determining the two-dimensional code based on the spreading of the points of such forming of the imager.

In some alternative, additional or cumulative embodiments, a method for reading a two-dimensional identification code in a substrate having one of the first and second opposing surfaces includes directing light toward the first surface of the substrate Where the light has a wavelength, and wherein the substrate and its first surface pair The wavelength is transparent, wherein the two-dimensional code is represented by a point spread in the substrate, wherein the point spreads a plurality of points including a group, and the points of the groups include points of the first group and the second group, wherein the points Each of the points of the first and second groups represents a geometric shape such that the points are interspersed to form an array of multiple columns and rows of geometric regions, wherein some of the geometric regions comprise a group of points and the geometries Some of the regions lack points in which a first portion of the light passes beyond the points and is absorbed at the second surface, wherein the second surface or one of the coatings applied thereto absorbs the wavelength, And wherein a second portion of the light passes through the second surface beyond the point and propagates through the first surface through the second surface; amplifying a second portion of light propagating through the first surface; using an imager Imaging the second portion of the light that propagates through the first surface and magnifying; analyzing an image of the second portion of the light and absorbing one of the black portions of the first portion of the light to determine the point Disperse; and based on the imager Such as the point of decision to distribute the two-dimensional code.

In some alternative, additional or cumulative embodiments, a method for reading an upper dimensional identification code in a substrate having one of the first and second opposing surfaces includes directing light toward the first surface of the substrate Wherein the light has a wavelength, and wherein the substrate and the first surface thereof are transparent to the wavelength, wherein the two-dimensional code is represented by a dot spread in the substrate, wherein the dot spreads a plurality of groups including dots The points of the group include points of the first group and the second group, wherein each of the points of the first and second groups represents a geometric shape such that the points are dispersed to form an array of multiple columns and rows of geometric regions , wherein some of the geometric regions comprise a group of points and some of the geometric regions lack points, wherein some of the light passes beyond the points and becomes reflected light by the second surface, wherein the second a surface or a coating applied thereto is reflective to the wavelength, wherein a first portion of the reflected light is blocked by the points and wherein a second portion of the reflected light passes beyond the points and propagates through The first surface of the substrate; Propagating through the reflecting surface of the first a second portion of the light; imaging the second portion of the reflected light that propagates through the second surface of the substrate by an imager; analyzing an image of the second portion of the reflected light and the reflected light The shadow caused by the blocking of the first portion determines the spread of the points; and the two-dimensional code is determined based on the spread of the points imaged by the imager.

In some alternative, additional or cumulative embodiments, the representative geometry is a rectangular geometry and the points of the first and second groups are positioned to represent the corners of the rectangular geometry.

In some alternative, additional or cumulative embodiments, the points of the first and second groups each comprise an even number of points.

In some alternative, additional or cumulative embodiments, the points of the first and second groups each comprise an odd number of points.

In some alternative, additional or cumulative embodiments, the point representing the two-dimensional code is invisible to the human eye at a distance greater than or equal to 25 mm from a human eye.

In some alternative, additional or cumulative embodiments, the array has an array size greater than 50 microns.

In some alternative, additional or cumulative embodiments, the array has an array size of greater than 500 microns.

In some alternative, additional or cumulative embodiments, the array has an array size of less than 500 microns.

In some alternative, additional or cumulative embodiments, the array has an array size of less than 250 microns.

In some alternative, additional or cumulative embodiments, the array has less than or equal to One array size of 1mm.

In some alternative, additional or cumulative embodiments, the points of the groups are not visible to the human eye at a distance greater than or equal to 25 mm from the human eye.

In some alternative, additional or cumulative embodiments, the points are invisible to the human eye at a distance greater than or equal to 25 mm from the human eye.

In some alternative, additional or cumulative embodiments, each point has a dimension of less than 35 microns for one of the main spatial axes.

In some alternative, additional or cumulative embodiments, each point has a point dimension of a primary spatial axis, and wherein a distance greater than or equal to four times the size of the point of the primary spatial axis separates the points.

In some alternative, additional or cumulative embodiments, the geometric region represents a square in a QR code.

In some alternative, additional or cumulative embodiments, the geometric regions represent squares in a GS1 DataMatrix code.

In some alternative, additional or cumulative embodiments, each point is formed by a laser pulse or by a group of laser pulses.

In some alternative, additional or cumulative embodiments, each point is formed by a laser pulse or a group of laser pulses, each laser pulse having a pulse width that is shorter than or equal to 50 ps.

In some alternative, additional or cumulative embodiments, the dots are black and the substrate is light colored.

In some alternative, additional or cumulative embodiments, the dots are made in a light color and the substrate is black.

In some alternative, additional or cumulative embodiments, the dots are black and the substrate is substantially transparent to visible light.

In some alternative, additional or cumulative embodiments, the substrate is opaque to visible light.

In some alternative, additional or cumulative embodiments, the substrate comprises a crystalline material.

In some alternative, additional or cumulative embodiments, the substrate comprises sapphire.

In some alternative, additional or cumulative embodiments, the substrate comprises an amorphous material.

In some alternative, additional or cumulative embodiments, the substrate comprises glass.

In some alternative, additional or cumulative embodiments, the substrate comprises a plastic.

In some alternative, additional or cumulative embodiments, the substrate comprises aluminum.

In some alternative, additional or cumulative embodiments, the laser pulses are directed to sequentially form a first group of points prior to forming a second group of points.

In some alternative, additional or cumulative embodiments, the laser pulses are directed to form a first point of each of the first and second groups prior to forming a second point in the first group.

In some alternative, additional or cumulative embodiments, a beam positioning system and a substrate support system cooperate to position the points of the laser beam relative to a position on the substrate, and wherein the points are positionally accurate Sex is worse than 10 microns.

In some alternative, additional or cumulative embodiments, a beam positioning system and a substrate support system cooperate to position the points of the laser beam relative to a position on the substrate, and wherein the points are positioned to a position The accuracy is worse than 5 microns.

In some alternative, additional or cumulative embodiments, one of the positioning systems and one The substrate support system cooperates to position the points of the laser beams relative to the position on the substrate, and wherein the positioning accuracy of the points to position is worse than 1 micron.

In some alternative, additional or cumulative embodiments, the points of the group provide a signal to noise ratio greater than or equal to one.

In some alternative, additional or cumulative embodiments, the separation or external separation between the points of the group may represent signal amplitude, and the coordinated beam positioning and the uncertainty or maximum inaccuracy of the workpiece support system may represent noise.

In some alternative, additional or cumulative embodiments, the spacing or external separation between the points of the groups is increased to increase the signal to noise ratio.

In some alternative, additional or cumulative embodiments, a controller is employed to convert the black squares of the two-dimensional code to respective locations on the substrate for the points of the groups.

In some alternative, additional or cumulative embodiments, a controller is employed to convert the black squares of the two-dimensional code to respective locations on the substrate for the points of the groups.

In some alternative, additional or cumulative embodiments, the array includes at least 50 geometric regions in a column or row.

In some alternative, additional or cumulative embodiments, the two-dimensional identification code is intended to be machine readable.

In some alternative, additional or cumulative embodiments, the light source is positioned to propagate the light along an illumination path that traverses the first surface, wherein the imager and the optical system are operable to receive from the second surface One of the reflected light is positioned in the imaging path.

In some alternative, additional or cumulative embodiments, the first electronic circuit analyzes the shadow caused by blocking light by the dots.

In some alternative, additional or cumulative embodiments, the light source is positioned to propagate the light along an illumination path that traverses the first surface, wherein the imager and the optical system traverse the first surface and are operable Positioning is performed on an imaging path that receives the light propagating through the first surface.

In some alternative, additional or cumulative embodiments, the points are at least partially reflective to the light, wherein the second surface or a layer thereon is at least partially absorbable to the light, and wherein the first electronic circuit analyzes The light reflected by the points.

In some alternative, additional or cumulative embodiments, the points are at least partially absorbable to the light, wherein the second surface or a layer thereon is at least partially reflective to the light, and wherein the first electronic circuit analyzes The shadow caused by blocking the light by the points.

In some alternative, additional or cumulative embodiments, the two-dimensional code is represented by a point spread within the substrate, wherein the point spreads points comprising a plurality of groups, the points of the groups comprising the points of the first and second groups , wherein each of the points of the first and second groups represents a geometric shape such that the points are interspersed to form an array of multiple columns and rows of geometric regions, and wherein some of the geometric regions comprise a group of points and Some of the geometric regions are missing points.

In some alternative, additional or cumulative embodiments, the illumination path traverses the first surface at a vertical angle.

In some alternative, additional or cumulative embodiments, the light source is positioned along an illumination axis that is substantially perpendicular to a first surface of the substrate.

In some alternative, additional or cumulative embodiments, the imager is positioned along the illumination axis.

In some alternative, additional or cumulative embodiments, the light source is positioned along an illumination axis having an incidence angle that is not perpendicular to the first surface of the substrate.

In some alternative, additional or cumulative embodiments, the illumination axis has an angle of incidence between 1 and 70 degrees.

In some alternative, additional or cumulative embodiments, the illumination axis has an angle of incidence between 10 and 65 degrees.

In some alternative, additional or cumulative embodiments, the illumination axis has an angle of incidence of less than or equal to 60 degrees.

In some alternative, additional or cumulative embodiments, the imager is positioned along an imaging axis that is perpendicular to one of the first surfaces.

In some alternative, additional or cumulative embodiments, the light source comprises an LED.

In some alternative, additional or cumulative embodiments, the light source provides a visible wavelength.

In some alternative, additional or cumulative embodiments, the light source provides one or more of the following wavelengths: 660 nm, 635 nm, 633 nm, 623 nm, 612 nm, 592 nm, 585 nm, 574 nm, 570 nm, 565 nm, 560 nm, 555 nm, 525 nm, 505 nm, 470nm and 430nm.

In some alternative, additional or cumulative embodiments, the light source provides a red wavelength.

In some alternative, additional or cumulative embodiments, the imager is monochrome.

In some alternative, additional or cumulative embodiments, the imager is full color.

In some alternative, additional or cumulative embodiments, the optical system employs optics that provide from 2x to 50x magnification.

In some alternative, additional or cumulative embodiments, the optical system employs optics that provide greater than 5x amplification.

In some alternative, additional or cumulative embodiments, the optical system is provided to provide greater than 10x magnification optics.

In some alternative, additional or cumulative embodiments, the optical system employs optics that provide less than 20x magnification.

In some alternative, additional or cumulative embodiments, the optical code reader has a modulation transfer function of greater than 50 line pairs per millimeter.

In some alternative, additional or cumulative embodiments, the optical code reader has a modulation transfer function of greater than 75 line pairs/mm.

In some alternative, additional or cumulative embodiments, the optical code reader has a modulation transfer function of greater than 80 line pairs/mm.

In some alternative, additional or cumulative embodiments, the optical code reader has a modulation transfer function of greater than 90 line pairs/mm.

In some alternative, additional or cumulative embodiments, the optical system provides a depth of field of approximately +/- 50 [mu]m.

In some alternative, additional or cumulative embodiments, the optical system provides a depth of field of approximately +/- 10 μm.

In some alternative, additional or cumulative embodiments, the optical system provides a depth of field of approximately +/- 2.5 [mu]m.

In some alternative, additional or cumulative embodiments, the optical system provides a field of view greater than or equal to about 500 [mu]m.

In some alternative, additional or cumulative embodiments, the optical system provides a field of view greater than or equal to about 800 [mu]m.

In some alternative, additional or cumulative embodiments, the optical system provides less than or equal At a field of view of approximately 800 μm.

In some alternative, additional or cumulative embodiments, the dots form a DM or 2DID code having a field size having a side dimension of less than 500 microns.

In some alternative, additional or cumulative embodiments, the dots form a DM or 2DID code having a field size having a side dimension of less than 250 microns.

In some alternative, additional or cumulative embodiments, the dots form a DM or 2DID code having a field size having a side dimension of less than 125 microns.

In some alternative, additional or cumulative embodiments, the dots form a DM or 2DID code having a field size of two dimensions of less than 250 microns.

In some alternative, additional or cumulative embodiments, the dots form a DM or 2DID code having a field size having two dimensions of less than 125 microns.

The additional aspects and advantages will be apparent from the following detailed description of the preferred embodiments of the drawings.

10‧‧‧ checkered pattern

12‧‧‧Reduced mark/mark

14‧‧‧Enlarged mark/mark

16‧‧‧ edge

18‧‧‧ misaligned mark/mark

30‧‧‧Group

32‧‧‧ points

40‧‧‧Laser micromachining system

42‧‧‧ surface

44‧‧‧Substrate

46‧‧‧Workpiece

50‧‧‧Laser

52‧‧‧Laser pulse

54‧‧‧ Controller

60‧‧‧ optical path

62‧‧‧Laser optics

64‧‧‧Folding mirror

66‧‧‧Attenuator or pulse picker

68‧‧‧Feedback sensor

70‧‧‧Laser beam positioning system

72‧‧‧ beam axis

80‧‧‧ focus

82‧‧ ‧ laser station

84‧‧‧Rapid Locator/Rapid Locator Z

86‧‧‧Workpiece table

88‧‧‧ Space energy distribution

90‧‧‧ waist

92‧‧‧ Spindle

94‧‧‧ Spindle

96‧‧‧ distance

98‧‧‧ distance

100‧‧‧ wafer

104‧‧‧ Surface

106‧‧‧ surface

130‧‧‧Coating material/index matching fluid

140‧‧‧flat surface

142‧‧‧flat surface

150‧‧‧ Cover

220‧‧‧Optical Marker Reader

220a‧‧‧Optical Marker Reader

220b‧‧‧Optical Marker Reader

220c‧‧‧Optical Marker Reader

220d‧‧‧Optical Marker Reader

220e‧‧‧Optical Marker Reader

220f‧‧‧Optical Marker Reader

220g‧‧‧Optical Marker Reader

222‧‧‧Light source

224‧‧‧ camera

226‧‧‧Light

226a‧‧‧Light

226b‧‧‧Light

226c‧‧‧Light

226d‧‧‧Light

226g‧‧‧Light

226h‧‧‧Light

226i‧‧‧Light

228‧‧‧ Imager

230‧‧‧Optical devices

232‧‧‧ lens

234‧‧•Video microscope unit/micro unit

240‧‧‧Diffuser

242‧‧‧ tube lens

250‧‧‧focus lens

260‧‧‧tube linear polarizer

262‧‧‧beam splitter

264‧‧ ‧ Collimation space

270‧‧‧Lighting catheter

272‧‧‧Lighting Path Mirror

274‧‧‧Lighting system

278‧‧‧ Collimating lens

280‧‧‧ pores

282‧‧‧Tube Linear Polarizer

286‧‧‧ catheter adaptor

290‧‧‧ catheter section

Figure 1 is an example of a conventional QR code.

Figure 2 is an example of a conventional GS1 DataMatrix code.

Figure 3 shows a smaller "black square" made by a laser superimposed on one of the 2DID codes on one of the squares.

Figure 4 is an enlarged representation of one of an exemplary pattern for replacing a laser spot of a dark square filled with one of the 2DID codes.

Figure 5 is a modified version of the GS1 DataMatrix code of Figure 2 in which the filled dark squares are replaced with the pattern of Figure 4.

Figure 5A is an enlarged portion of Figure 5 that facilitates the difference between the internal separation distance, the external separation distance, and the spacing.

Figure 6 is a simplified and partially schematic perspective view of some of the components of an exemplary laser micromachining system, one of the points suitable for generating a modified 2DID code.

Figure 7 shows a map of a laser pulse focus and its waist.

Figure 8 is a cross-sectional side view of a sapphire wafer having a rough surface covered by a coating material and a cover.

Figure 9 is a simplified partial schematic side view of some of the components of an exemplary optical indicia reader suitable for reading a modified 2DID code.

Figure 10 is a simplified partial schematic side elevational view of some of the components of another exemplary optical indicia reader adapted to read the modified 2DID code.

Figure 11 is a simplified partial schematic side view of some of the components of a further exemplary optical indicia reader suitable for reading one of the modified 2DID codes.

Figure 12 is a simplified partial schematic side elevational view of some of the components of yet another exemplary optical indicia reader suitable for reading a modified 2DID code.

Figure 13 is a simplified partial schematic side elevational view of still some of the components of another exemplary optical indicia reader adapted to read a modified 2DID code.

Figure 14 is a simplified partial schematic side view of still some of the components of another exemplary optical indicia reader adapted to read the modified 2DID code.

Figure 15 is a simplified partial schematic side elevational view of some enlarged portions of Figure 14.

Example embodiments are described below with reference to the drawings. Without departing from the essence of this disclosure Many different forms and embodiments are possible, and thus the disclosure is not to be considered as limited to the example embodiments set forth herein. Rather, the example embodiments are provided so that this disclosure will be thorough and complete and the scope of the disclosure will be disclosed to those skilled in the art. In the figures, the size and relative size of the components can be expanded for clarity. The terminology used herein is for the purpose of describing particular example embodiments and is not intended to As used herein, the singular forms " It will be further understood that the term "comprises" and / or "comprising" when used in this specification is intended to mean the existence of the stated features, integers, steps, operations, components and/or components, but not Exclusions or additions of one or more other features, integers, steps, operations, components, components, and/or groups thereof are excluded. Unless otherwise specified, the range of one of the stated ranges includes both the upper and lower limits of the range and any sub-ranges thereof.

Some 2DID codes have been marked inside the glass, for example by using TRACKinside® technology (see http://www.totalbrandsecurity.com/?page_id=209#&panel1-1). Equipped with the appropriate lasers operating under a combination of parameters, many laser micromachining systems (such as models MM5330 and MM5900) manufactured by Electro Scientific Industries of Portland, Oregon, USA, are also suitable for use in a variety of materials (such as ceramics, The 2DID code is made on or in the glass, metal or a combination thereof.

As marking on smaller components has been desired, the size of the 2DID code has become smaller. Moreover, the availability of "invisible" DM or 2DID codes is useful for some applications (such as transparent materials for screens that are used as a non-blocking viewing angle, or for various purposes (such as detecting genuine and fake products) ) Exclusive information or covert manufacturing marks) useful.

One method for making a DM or 2DID code invisible is to reduce the size of the code until the entire array of black squares is too small to be seen by the human eye. The theoretical maximum angular resolution of the human eye corresponds to 1.2 arc minutes at d = 0.75 mm (350 microns) at a distance of 1.0 m and d = 0.7 mm at a distance of 2.0 m. For convenience, this maximum angular resolution can be expressed as: d 0.35x mm, where d is the point size in millimeters and x is the distance from the eye to the point in meters.

However, at a closer distance (such as for reading a typical distance (about 25 cm) of a mobile phone screen), the DM or 2DID code would have to be smaller to be invisible (about 87.5 microns), and the individual squares must be even smaller. . Even though a laser can be used to make the individual squares small enough, the black squares will most likely be sized to equal the point size under a single laser pulse. For example, a conventional smaller laser spot size (such as about 5 microns) would limit this invisible DM or 2DID code to include up to 17 squares in a column or row. The practical limitation of the small size of the laser spot is generally accepted to be approximately twice the wavelength of the laser, and thus a point size of less than about 1 micron or 2 microns may be difficult and expensive to use. Therefore, there are a large number of cost and technical limitations for more obvious DM or 2DID code reduction.

Figure 3 shows a "black square" made by a simulated laser superimposed on one of the DM or 2DID codes on the one-frame pattern 10. Actual lasers and materials can cause laser markings in a hazy, distorted shape that are not properly aligned and not completely black, but rather shaded in gray. All of these factors (blur, shape distortion, misalignment, and low contrast shadows) lead to less certainty about whether a particular square should be classified as "black" or "white." Some of these factors can result from unpredictable laser cavity effects, transients or long-term misalignment of optical components or transients or long-term inconsistencies in beam positioning components and laser timing. These uncertainties are collectively referred to as "noise."

The black squares and grid patterns made by these lasers shown in Figure 3 reveal how these problems can increase noise as a 2DID code shrinks. In particular, Figure 3 shows a reduced mark 12, an enlarged mark 14 and a non-uniform edge 16 caused by system noise. 3 also shows one of the misalignment marks 18 that can be caused by positional inaccuracies or coordinate inaccuracies in the beam positioning or substrate positioning system or with respect to timing inaccuracies generated by such systems and laser pulses. These twist marks (specifically, marks 14 and 18) can make interpretation of the optical code reader difficult even under the most sophisticated optics and error correction software.

The signal-to-noise ratio (SNR) of the marked DM or 2DID code determines whether the code will be sufficiently non-distorted to minimize the error in reading the 2DID code. The size of the individual squares in the 2DID code is proportional to the signal strength, but the distortion of the shape and size of the individual squares is proportional to the noise. Moreover, the signal amplitude can be determined by the spatial separation between the patterns representing the points of the squares and the noise amplitude can be determined by the accuracy of the system used to mark the points. Thus, as the size of individual squares becomes smaller, the signal strength is lower and the code is more susceptible to distortions (such as blur or line distortion) that can occur in less than perfect marking machines.

However, Electro Scientific Industries of Portland, Oregon, enables a laser micromachining system to be less than 10 microns by precisely controlling the alignment, timing, and coordinates of system components and by limiting the processing window parameters of the laser system. The laser spot is accurately delivered to the desired location on a workpiece 46 (Fig. 6) to successfully overcome many of these problems. In a particular embodiment, a microscopic 2DID code of one square of a 126 x 126 micron array is formed, wherein each designated black square is represented by a 4 to 5 micron dot. Moreover, the laser micromachining system used to make this 2DID code is very large and uses very expensive components.

In order to utilize a laser to reduce the system used to generate invisible DM or 2DID codes Cost, the applicant pursues a completely different paradigm. The applicant decides that the 2DID code can be represented by a modified 2DID code containing a point that makes the human eye invisible to each of the black squares of the 2DID code, instead of dealing with and reducing an entire 2DID code to a small enough for the human eye. The costs and problems of invisible associations.

4 is an enlarged representation of one exemplary pattern or group 30 for replacing a dark square laser mark or point 32 filled with one of the conventional 2DID codes. As mentioned above, for the sake of convenience, the maximum angular resolution of the human eye can be expressed as d 0.35x mm, where d is one of the major points of the laser point in millimeters and x is the distance from the eye to the point in meters. Thus, for a typical minimum reading distance of about 125 cm, each point in the 2DID code would have to have a major axis that has a point size that is shorter than or equal to about 44 microns to be invisible to the human eye (such as when zoomed in) Under micro-viewing) still visible).

During the experiment with the grouping pattern, the Applicant indicates that when the invisible dots 32 are closely grouped together, they may look like a single point of a larger size, thus making the group 30 of points 32 visible. However, when the center-to-center separation s of point 32 is greater than four times the diameter as shown in Figure 4 (ie, s 4d), based on experimental empirical data, it is confirmed that the circular shape point 32 having a diameter d looks like an individual point (relative to a cluster of points that appear to be a single point).

Simple software can be used to convert a conventional 2DID code into a modified form, wherein each black square (or each data point) is represented by a pattern of dots 32 (sub-data points), wherein each individual point 32 is selected to have sufficient The center-to-center spacing or distance between any two points 32 that is invisible to the human eye is less than four times the maximum cross-sectional dimension of the individual points 32 (eg, the main spatial axis d). Therefore, the shape of each point 32 and the size of the point 32 can be selected. The circular points 32 are generally the easiest to produce, but for example, square or elliptical dots 32 may also be employed. class Similarly, the spatial energy distribution forming each point 32 need not be uniform.

In general, the primary spatial axis d of each point 32 is between about 0.5 microns and about 90 microns. (less than about 87.5 microns, one of the main spatial axes d is invisible to the human eye at a distance of 25 cm.) In some embodiments, the main spatial axis d of the points 32 is between about 1 micrometer and about 75 micrometers, or The main space axis d of point 32 is shorter than 75 microns. In some embodiments, the primary spatial axis d of the point 32 is between about 1 micrometer and about 50 micrometers, or the principal spatial axis d of the point 32 is shorter than 50 micrometers. (One of the primary spatial axes d less than about 43.75 microns is invisible to the human eye at a distance of 12.5 cm.) In some embodiments, the primary spatial axis d of the points 32 is between about 1 micrometer and about 25 micrometers, Or the main spatial axis d of point 32 is shorter than 25 microns. (One of the principal space axes d less than about 22 microns is invisible to the human eye at a distance of 6.25 cm. In general, a point size of about 30 microns or less is invisible to most human eyes at any distance, this Due to the anatomical limitations of the human eye and the optical limitations of conventional glasses.) In some embodiments, the principal spatial axis d of the point 32 is between about 1 micrometer and about 10 micrometers, or the principal spatial axis d of the point 32. Shorter than 10 microns. In some embodiments, the main spatial axis d of the point 32 is between about 1.5 microns and about 5 microns, or the main spatial axis d of the point 32 is shorter than 5 microns.

In general, it is advantageous to make the main spatial axis d of point 32 as small as possible (and at least small enough so as not to significantly increase the cost of the laser micromachining system or significantly increase the cost of the optical code reader). Detrimentally affecting the substrate to be marked). It will be understood that the smaller the main spatial axis d of point 32 is made, the smaller the minimum point separation distance s can be made without making the group 30 of points 32 visible (and the overall 2DID code size can be made more small). However, it will also be appreciated that there may be an advantage in spacing the points 32 apart by a separation distance that is significantly greater than the minimum separation distance s to increase the signal to noise ratio even when the main spatial axis d of the point 32 is minimized.

For simplicity, each point 32 can be similar in shape and size and formed with a similar spatial energy distribution; however, if desired, such characteristics can be deliberately altered for a particular point 32. Moreover, because of the favorable signal-to-noise ratio, unintentional differences in characteristics between different points 32 do not cause optical read errors.

In some embodiments, the minimum separation distance s is greater than or equal to 4 microns based on a point size of about 1 micron and the applicant's empirical data. In an exemplary array of one of 177 x 177 DM or 2DID codes to be marked with a 1 mm x 1 mm field, the separation distance s between 1 micron points 32 can be as large as about 5.6 microns. Of course, the field of the modified 2DID code need not be so small, and thus the maximum separation distance s can be determined by dividing the size of the substrate by the number of columns of the 2DID code or the number of geometric regions in the row. For example, a 10 cm x 10 cm field of one 177 x 177 2DID code can provide a separation distance s of up to a 565 micrometer between 1 micrometer dots 32; one of a 57 x 57 2 DID code 20 cm x 20 cm field can be at a micron point of 32 A separation distance s of up to 3500 microns is provided therebetween; or a 1 mm x 1 mm field of one 21 x 21 2 DID code can provide a separation distance s of up to about 40 microns between 25 micrometers 32. As mentioned earlier, the larger separation distance s provides a larger signal to noise ratio. Moreover, the nature of the laser micromachining system can affect the choice of separation distance s between points 32. For example, if a laser micromachining system has a point location accuracy of about +/- 20 microns, a separation distance s of 40 microns may be advantageous.

A group of areas may be defined by points 32 that form the perimeter of the spread of points in group 30. Each point 32 in group 30 has a point size or point area as previously discussed. A cumulative point area may represent the sum of the area of points 32 of a group 30. In some embodiments, the cumulative spot area is less than or equal to less than 10% of the group area. In some embodiments, the cumulative spot area is less than or equal to less than 5% of the group area. In some embodiments, the cumulative point area is less than or equal to less than the group 1% of the area. In some embodiments, the cumulative spot area is less than or equal to less than 0.5% of the group area. In some embodiments, the cumulative spot area is less than or equal to less than 0.1% of the group area.

Figure 5 is a modified version of the GS1 DataMatrix code of Figure 2 in which the black (designated) squares in the array are replaced with the pattern of point 32 of Figure 4. Group 30 of points 32 is shown having four points 32 arranged in a pattern such that each point 32 is positioned close to a designated square or positioned at one of the corners of a designated square.

The field size of the modified DM or 2DID code array is limited only by the size of the substrate 44 on the workpiece 46 (Fig. 6) to be marked. In many embodiments, the field will be less than 20 cm x 20 cm and greater than 50 microns x 50 microns. In some embodiments, the field will be less than or equal to 500 microns by 500 microns (and greater than 1 micron by 1 micron). In some embodiments, the field will be less than or equal to 250 microns by 250 microns (and greater than 1 micron by 1 micron). In some embodiments, the field will be less than or equal to 100 microns by 100 microns (and greater than 1 micron by 1 micron).

In some embodiments, the modified 2DID code size will be greater than or equal to 600 microns by 600 microns. In some embodiments, the size of the modified 2DID code will be less than or equal to 1 mm x 1 mm. In some embodiments, the size of the modified 2DID code will be greater than or equal to 1 mm x 1 mm and less than or equal to 10 mm x 10 mm. In some embodiments, the size of the modified 2DID code will be greater than or equal to 1 cm x 1 cm and less than or equal to 10 cm x 10 cm. As mentioned previously, the nature of the selected laser micromachining can affect the spot size and limit the localization field. Because of the structural integrity or advantages that can be used to maximize the separation distance s in some materials, the nature of the substrate 44 can also affect the field size of the array. In addition, the size and cost of the optical code reader and its ability to process and detect the code can also be a factor in determining the appropriate field size of the 2DID code array. Finally, the purpose of modifying the 2DID code can affect the size of the field selected for its array.

It will be appreciated that the geometric regions in the array need not be square. For example, they may be triangular or hexagonal. Moreover, the number of dots 32 and the pattern of dots 32 in groups 30 of each geometric region may be arbitrary or may be selected to some extent. For example, five points may represent respective designated geometric regions (such as a square) with four points 32 positioned at the corners and a point 32 positioned intermediate. Thus, each designated geometric region can be represented by an even number of points or by an odd number of points. In this embodiment, four of the points 32 are separated from the intermediate point 32 by a selected distance s because the distance s is the shortest distance between any two points 32 in the group 30. Therefore, the corner (or perimeter) points are separated by a distance greater than one of s. Thus, point 32 (or nearest neighbor 32) in a group 30 can be separated by unequal distances.

As mentioned previously, the specified geometric region in the array need not be represented by a geometric pattern similar to one of the geometric regions. For example, a designated square geometric region may be represented by other geometric patterns including, but not limited to, a rectangular pattern, a circular pattern, a hexagonal pattern, an octagonal pattern, or a triangular pattern. For convenience and simplicity, each of the designated geometric regions provides the same geometric pattern of a bit 32. However, the selected geometric region may be indicated by a different number of dots 32, one of the patterns of dots 32, a different size or a different pattern of dots. For example, the position squares of a QR code and/or alignment squares may be represented by different patterns or by patterns of different sizes.

Referring to Figure 3, there is no intentional separation between the squares of adjacent marks, and the distance between the squares of the marks has the same size as the side of the square of the marks. Thus, in the embodiment shown in Figure 3, the noise can be equivalent to a signal. However, referring again to FIG. 5, in many embodiments, the adjacent group 30 of points 32 can be separated up to an external separation distance e (the smallest separation distance from adjacent points of the different groups) and a spacing p (phase The center-to-center spacing between adjacent geometric regions or their representative groups. Fig. 5A is an enlarged portion of Fig. 5 which facilitates the difference between the internal separation distance s , the external separation distance e and the pitch p .

In many embodiments, the pitch p will be different from and greater than the outer separation distance e , and both the pitch p and the outer separation distance e will be different and generally greater than the selected minimum separation distance between the points 32 in a group 30. s .

Moreover, in some embodiments, the external separation distance e between the columns or rows in the array can be greater than or equal to 1 s to maintain a desired signal to noise ratio. It will be appreciated that the external separation distance e between the columns can be different from the external separation distance e between the rows. It will also be appreciated that for earlier instances of list point size, field size, and number of groups 30 in a column or row, the external separation distance e between the columns may reduce the separation s by more than half.

Similarly, in some embodiments, the distance p between columns or rows in the array can be greater than or equal to 1 s to maintain a desired signal to noise ratio. I will also understand that the distance p between columns can be different from the distance p between rows. It will also be appreciated that for earlier instances of the list of point sizes, field sizes, and the number of groups 30 in a column or row, the distance p between the columns may reduce the separation distance s by more than half.

Thus, the signal to noise ratio can also be improved by making the overall size of the geometric regions (such as squares) much larger than the perimeter defined by the pattern of dots 32 (if the pattern is grouped near the center of the geometric region).

In some embodiments, the signal amplitude can be represented by an external separation distance e or pitch p . The noise amplitude can be represented by the uncertainty or inaccuracy of the point location relative to a particular location on the substrate 44. For example, if the laser micromachining system of the marked point has a mark inaccuracy of +/- 20 microns, this inaccuracy will indicate noise. Therefore, the signal-to-noise ratio will be the ratio of the external separation distance e or the pitch p to the mark inaccuracy. If the inaccuracy of the mark inherent in a laser system is allowed to be large or deteriorates over time, the external separation distance e or pitch p may be increased to maintain an appropriate signal-to-noise ratio. Alternatively, if the inaccuracy is known to be a fixed number, the signal to noise ratio can be increased to an arbitrarily large number by increasing the external separation distance e or pitch p .

In view of the above, the signal-to-noise ratio can be easily established to be greater than 5, which is based on the Ross criterion as the minimum signal-to-noise ratio capable of distinguishing image features at 100% determination. However, it should be understood that a signal to noise ratio of less than 5 can be employed. Moreover, the modified two-dimensional code described herein can provide any large signal-to-noise ratio, such as greater than or equal to 10, greater than or equal to 100, or greater than or equal to 1000.

In some alternative embodiments, the spacing between columns or rows in the array is not used such that patterns in adjacent designated geometric regions can share point 32. For example, two corner patterns adjacent to a given square geometric region may share two points 32 along the boundaries of the two square geometric regions. The optical code reader will have to be adapted to identify, for example, three pairs of evenly spaced points 32 representing two designated squares.

Regardless of the size between arrays, the separation distance between a point of 32 s, the distance separating the external e (if any) or the column size and the distance p, the selected pattern group 30 and the geometric area of the spacing between the rows and The shape 32 can be converted back to a specified geometric area (such as a black square).

As mentioned previously, the advantages of modifying the 2DID code as described herein include methods for rendering the 2DID code invisible to the human eye in various substrate materials (transparent or opaque materials). Exemplary materials include ceramic, glass, plastic, and metal or combinations thereof. Exemplary materials can be crystalline or amorphous. Exemplary materials can be natural or synthetic. For example, a laser micromachining system can be made of a suitably sized mark on or within a semiconductor wafer material (this alumina or sapphire). Laser micromachining system also in glass, tempered marker made of a suitable size and the glass or the Corning Gorilla Glass ^TM. Laser micromachining systems can also be made of appropriate size markings on or in polycarbonate and acrylate. Laser micromachining systems can also be made of appropriate size markings on or in aluminum, steel and titanium.

The invisible mark of the modified DM or 2DID code not only provides a method of placing the code without blurring the transparent material, but also provides a method of hiding the proprietary information within the modified code. For example, multiple patterns may be provided within a modified 2DID code, with only some of the patterns containing proprietary information. In addition, the small and expansion points 32 can be configured to appear to be incomplete in the substrate material, thus making it difficult for a competitor or potential copyer to know that there is a modified 2DID code. Finally, the modified 2DID code can be made more complex than the standard 2DID code, so the modified 2DID code can be more difficult to identify and copy by a counterfeiter.

Regardless of whether the 2DID code is rendered invisible, the modified 2DID code achieves a significant improvement over the signal-to-noise ratio (SNR) of the conventional 2DID code by extending the modified code over an arbitrarily large area. Moreover, regardless of whether point 32 is invisible, the modified 2DID code reduces the error and reduces the cost and time (processing power) of the error correction.

Another advantage of extending the 2DID code over a larger area enables the use of less expensive and less accurate laser marking systems while maintaining invisibility if desired.

As previously mentioned, the dots 32 can be marked on or within the substrate material of the workpiece 46 (Fig. 6). Internal marker points 32 may be advantageous for many applications. The invisible point 32 is very small and is more likely to cause some material to wear or be easily worn. However, internal markings are not as easy to wear or wear as normal. Internal marking also allows the surface to remain relatively impermeable to dust or fluid and less likely to compromise structural integrity or promote surface crack extension or other surface defects.

In general, the internal indicia can comprise one or more of cracking, density modification, hole generation, stress field, or recrystallization of the core material between the surfaces of a substrate 44.

Can be selected to improve the reliability and repeatability of the laser markings of substrate 44 Exemplary laser pulse parameters include laser type, wavelength, pulse duration, pulse repetition rate, number of pulses, pulse energy, pulse time shape, pulse space shape, and focus size and shape. The additional laser pulse parameters include the relative motion of the specified focus relative to the surface of the object and directed to the laser pulse relative to the object.

6 is a simplified and partially schematic perspective view of some of the components of an exemplary laser micromachining system 40 that is suitable for generating a modified 2DID code. Referring to Figure 6, some exemplary laser processing systems operable to mark points 32 on or under one surface 42 of substrate 44 of workpiece 46 are ESI MM5330 micromachining systems, ESI ML5900 micromachining systems, and ESI 5955 micromachining. The system is manufactured by Electro Scientific Industries, Inc., 97229 Portland, Oregon.

Such systems typically employ a solid state diode pumped laser that can be configured to emit wavelengths from about 266 nm (UV) to about 1320 nm (IR) at pulse repetition rates of up to 5 MHz. However, such systems may be replaced or otherwise adapted by appropriate lasers, laser optics, component handling equipment, and control software to reliably and reproducibly select selected points 32 on or within substrate 44 as previously described. Such modifications allow the laser processing system to direct laser pulses having appropriate laser parameters to a desired position on a suitably positioned and held workpiece 46 at a desired rate and between laser points or pulses to produce The desired point 32 has the desired color, contrast, and/or optical density.

In some embodiments, the laser micromachining system 40 employs a diode-pumped Nd:YVO ₄ solid state laser 50 operating at a wavelength of 1064 nm, such as one manufactured by Lumera Laser GmbH of Kaiserslautern, Germany. Model Rapid. A solid-state harmonic frequency generator can be used to double the laser frequency to reduce the wavelength to 532 nm, thereby producing a visible (green) laser pulse, or increasing the frequency by a factor of three to about 355 nm or four times the frequency to Approximately 266 nm, thereby generating ultraviolet (UV) laser pulses. This laser 50 is rated to produce 6 watts of continuous power and has a maximum pulse repetition rate of 1000 KHz. This laser 50, in cooperation with controller 54, produces a laser pulse 52 (Fig. 7) having a duration of from 1 picosecond to 1,000 nanoseconds.

In some embodiments, the laser micromachining system 40 employs an erbium-doped fiber laser pumped with one of the base wavelengths in the range of about 1030 nm to 1550 nm. A solid-state harmonic frequency generator can optionally be used to double the laser frequencies to reduce the wavelength to approximately 515 nm, thereby producing a visible (green) laser pulse or reducing to approximately 775 nm, thereby producing (eg) visible (deep) The red) laser pulse or frequency is increased by a factor of three to about 343 nm or about 517 nm or the frequency is increased by a factor of four to about 257 nm or about 387.5 nm, thereby producing an ultraviolet (UV) laser pulse.

These laser pulses 52 may be Gaussian functions or specially shaped or customized by laser optics 62, which typically include one that is positioned along an optical path 60 to allow for the desired characteristics of point 32 or Multiple optical components. For example, a "top hat" spatial distribution can be used that delivers a laser pulse 12 having a uniform dose of radiation that strikes one of the substrates 44 over the entire point 32. The spatial distribution of such special shaping can be produced using diffractive optical elements or other beam shaping components. A detailed description of the modification of the spatial irradiance distribution of the laser spot 32 is found in U.S. Patent No. 6,433,301, the entire disclosure of which is incorporated herein by reference. in.

The laser pulse 52 propagates along an optical path 60, which may also include a folding mirror 64, an attenuator or pulse picker (such as an acousto-optic or electro-optic device) 66, and a feedback sensor (such as for energy, timing). Or location) 68.

Laser optics 62 and other components along optical path 60 cooperate with one of laser beam localization systems 70 directed by controller 54 to direct a beam 72 of one of the laser pulses 52 propagating along optical path 60 to The laser spot position forms a laser focus 80 at a surface 42 proximate to the substrate 44. The laser beam positioning system 70 can include a laser stage 82 operative to move the laser 50 along a travel axis (such as the X axis) and a rapid locator table 84 along a travel axis (such as Z-axis) moves a quick locator (not shown). A typical rapid positioner employs a pair of galvanometer controlled mirrors that are capable of rapidly changing the direction of the beam axis 72 over a larger field on the substrate 44. This field is typically smaller than the mobile field provided by the workpiece table 86 as described later. An acousto-optic device or a deformable mirror can also be used as a rapid locator, even if such devices tend to have a smaller beam deflection range than the galvanometer mirror. Alternatively, an acousto-optic device or a deformable mirror can be used as one of the high speed positioning devices in addition to the galvanometer mirror.

Additionally, the workpiece 46 can be supported by a workpiece table 86 having motion control elements operable to position the substrate 44 relative to the beam axis 72. The workpiece table 86 is operable to travel along a single axis (such as the Y-axis) or the workpiece table 86 is operable to travel along a lateral axis (such as the X-axis and the Y-axis). Alternatively, the workpiece table 86 is operable to rotate the workpiece 46 (either alone or along the X and Y axes) about a Z axis, such as.

The controller 54 can coordinate the operation of the laser beam positioning system 70 and the workpiece table 86 to provide a composite beam positioning capability that facilitates marking points 32 on or in the substrate 42 while the workpiece 46 can be in continuous relative motion relative to the beam axis 72. . This capability is not necessary to mark points 32 on substrate 42, but this capability may be desirable for increased processing power. This ability is described in U.S. Patent No. 5,751,585, the entire disclosure of which is incorporated herein by reference. Additional or alternative methods of beam positioning may be employed. At Spencer Barrett Some additional or alternative methods of beam locating are described in U.S. Patent No. 6,706, 999, the disclosure of which is incorporated herein by reference. in.

The various beam positioning systems described herein can be controlled to provide beam positioning accuracy of the laser spot position within a few microns of a desired position of a point 32 on the substrate 44. However, it should be noted that high accuracy can be implemented with higher cost components, greater feedback control, and slower system processing power. In general, the beam positioning error can be as large as one-half the separation distance due to the significantly increased signal-to-noise ratio of the DM or 2DID code supply modified as described herein. For very large fields, this tolerance can be quite large, such as 1 mm. However, even very low cost laser micromachining systems can achieve greater accuracy. Applicants have decided that for many embodiments, even for smaller fields, the position of the laser spot may be as large as +/- 20 microns of the desired position of one of the points 32 on the substrate 44. For many embodiments with very small fields, the position of the laser spot can be as large as +/- 10 microns of the desired position of one of the points 32 on the substrate 44. However, for minimized field size, the error in the position of the laser spot can be as large as +/- 1 micron of the desired position of one of the points 32 on the substrate 44.

The cost of producing a 126 x 126 micron demonstration +/- 0.5 micron accuracy laser micromachining system can greatly exceed one million dollars. The cost for a +/- 20 micron accuracy laser micromachining system can be about one tenth of the cost of a more accurate machine (ie, approximately $100,000). Moreover, the more accurate machine is much larger and requires a tightly controlled temperature environment (and controlled vibration), but the +/- 20 micron accuracy machine is significantly smaller and can work in a typical factory environment without special limitations. .

Figure 7 shows a view of the focus 80 and its waist portion 90. Referring to Figure 7, the focus 80 of the laser pulse 52 will have a majority of the waist 90 (section) and laser energy spread determined by the laser optics 62. The main spatial axis d of point 32 is typically a function of one of the major axes of the waist and both may be the same or similar. However, the main spatial axis d of the point 32 may be larger or smaller than the major axis of the waist.

Laser optics 62 can be used to control the depth of focus of the waist and thus the depth of point 32 within substrate 44. By controlling the depth of focus, the controller 54 can direct the laser optics 62 and the rapid locator Z stage 84 to reproducibly position the point 32 at or near the surface of the substrate 44 with high precision. The marking is made by positioning the focus above or below the surface 42 of the substrate 44 to allow the laser beam to defocus a specified amount and thereby increase the area illuminated by the laser pulse and reduce the laser flux at the surface 42 (reduced to Less than one of the damage thresholds of the material at the surface). Because the geometry of the waist is known, accurately positioning the focus 80 above or below the actual surface 42 of the substrate will provide additional precision control over the main space axis d and flux.

In some embodiments, such as for marking a transparent material, such as sapphire, the core can be at the core of the substrate 44 by adjusting the position of the laser spot from the surface 42 of the substrate 44 to a precise distance within the substrate 44. Precise control of laser flux. Referring to Figure 7, the waist portion 90 is shown as a spatial energy spread 88 along one of the laser pulses 52 of the beam axis 72 as measured by the FWHM method. If the laser micromachining system 40 focuses the laser pulse 52 at a distance 96 above the surface 42, the spindle 92 represents the size of the laser pulse spot on the surface 42. If the laser processing system focuses the laser pulse at a distance 98 below the surface, the spindle 94 represents the size of the laser pulse spot on the surface 42. With respect to most of the embodiments in which the interior of the dot 32 is desired, the focus 80 is directed to be positioned within the substrate 44 rather than above or below its surface 42. Flux or irradiation may be employed at an amount below the ablation threshold of the substrate material other than the focus 80 at which the flux or radiation concentrates beyond the ablation threshold of the substrate material.

In some embodiments, a group of laser pulses can be employed to generate a single point 32. In particular, the laser parameters can be selected such that each laser pulse affects an area that is less than one of the desired sizes for point 32. In such cases, a plurality of laser pulses can be directed to a single location until point 32 reaches a desired size (which may still be undetectable by the human eye). The group of laser pulses can be transmitted in relative motion or in a substantially relative rest position.

The laser parameters that may be advantageously employed for some embodiments include the use of a laser 50 having a wavelength in the range from IR to UV, or more specifically, from about 10.6 microns down to about 266 nm. The laser 50 can operate at 1 W in the range of 1 W to 100 W, or more preferably, 1 W to 12 W. The pulse duration is in the range from 1 picosecond to 1000 ns, or more preferably from about 1 picosecond to 200 ns. The laser repetition rate can range from 1 KHz to 100 MHz, or more preferably, from 10 KHz to 1 MHz. Laser flux can be from about 0.1 × 10 ^-6 J / cm ² to 100.0J / cm ^2, or more specific words, from 1.0 × 10 ^-2 J / cm ² to the range of 10.0J / cm ² of the medium. The speed at which the beam shaft 72 moves relative to the substrate 44 being marked is in the range of from 1 mm/s to 10 m/s, or more preferably, from 100 mm/s to 1 m/s. The spacing or spacing between points 32 of adjacent columns on substrate 44 can range from 1 micron to 1000 microns, or more preferably, from 10 microns to 100 microns. The main spatial axis d of the laser pulse 52 measured at the surface 42 of the substrate 44 can range from 10 microns to 1000 microns or from 50 microns to 500 microns. Of course, if point 32 is desired to be invisible, the main spatial axis d is preferably less than about 50 microns. The rise of the focus 80 of the laser pulse 52 relative to the surface 42 of the substrate 44 may range from -10 mm to +10 mm or from -5 mm to +5 mm. In many embodiments for surface marking, the focus 80 is positioned at the surface 42 of the substrate 44. For many embodiments of the internal indicia, the focus 80 is positioned below the surface 42 of the substrate 44 (between the surfaces of the substrates 44). For some embodiments of the internal indicia, the focus 80 is positioned at least 10 microns below the surface 42 of the substrate 44. For some embodiments of the internal indicia, the focus 80 is positioned at least 50 microns below the surface 42 of the substrate 44. For some embodiments of the internal indicia, the focus 80 is positioned at least 100 microns below the surface 42 of the substrate 44.

Applicants have found that the use of a surface focus 80 and the use of a picosecond laser that produces a laser pulse width in the range from 1 picosecond to 1,000 picoseconds can be reliably provided in some transparent semiconductor substrates 44, such as sapphire. And a better method of reproducibly generating one of the markers. In some embodiments, a pulse width in the range from 1 ps to 100 ps may be employed. In some embodiments, a pulse width in the range from 5 ps to 75 ps can be employed. In some embodiments, a pulse width in the range from 10 ps to 50 ps may be employed. It is speculated that a femtosecond laser that produces a wavelength in the range of 10 to 1000 femtoseconds may alternatively provide better results. However, one advantage of using a picosecond laser is that it is much less expensive, requires much less maintenance, and typically has a much longer operational life than existing femtosecond lasers.

While the marking can be accomplished at various wavelengths as previously discussed, Applicants have found that IR lasers operating in the picosecond range provide reproducible better results. Wavelengths at 1064 nm or around 1064 nm are particularly advantageous. An exemplary laser 50 series is a Lumera 6W laser. It will be appreciated that fiber lasers or other types of lasers may be employed.

Similar parameters can also be used to make invisible subsurface markings in metal or coated metals such as anodized aluminum. Customized markings for the anodized aluminum substrate 44 are described in detail in U.S. Patent No. 8,379,679 and U.S. Patent Publication No. 2013-0208074, both of which are owned by Haibin Zhang et al. The assignee of the present application is hereby incorporated by reference.

As previously discussed, the transparent semiconductor substrate material can be internally marked by selectively directing the laser output at the substrate material. The internal markings of the substrate 44 maintain the integrity of the surface 42, Such as waterproof and dustproof. Internal marking also reduces crack propagation and other adverse effects caused by surface markings.

Referring to Figure 8, Applicants have also indicated that wafer 100 or other semiconductor substrate material cut from a single crystal block tends to have surfaces 104 and 106 having a rough surface texture. The surface texture of such surfaces 104 and 106 in their natural state can adversely affect the optical properties of the laser pulses 52 directed at the substrate 44 of the wafer 100.

The Applicant also determined that the substrate 44 having the wafer 100 having one of the rough textured surfaces 104 or 106 (such as an unpolished surface) may be difficult to internally mark without causing damage to the surface 104 or 106.

The adverse optical effects of the rough surface can be mitigated by employing a flat surface 140 or 142 that effectively provides a coating material 130 that is one of the laser outputs 110. The flat surface 140 represents the upper surface of the coating material 130. The flat surface 142 is used for the flat surface of the outer cover 150 of one of the coating materials 130. The coating material 130 has a refractive index that is optically compatible with the refractive index of the substrate.

The refractive index of the coating can be within 2 of the refractive index of the substrate (such as at 25 degrees Celsius). The refractive index of the coating can be within 1 of the refractive index of the refractive index of the substrate. The refractive index of the coating can be within 0.5 of the refractive index of the refractive index of the substrate. The refractive index of the coating can be within 0.2 of the refractive index of the refractive index of the substrate. The refractive index of the coating can be between 1.2 and 2.5. The refractive index of the coating can be between 1.5 and 2.2. The refractive index of the coating can be between 1.7 and 2.0. The refractive index of the coating can be between 1.75 and 1.85. The outer cover can also have a matching index of refraction in these ranges.

Coating material 130 can include a fluid, a gel, or an oil. The coating material 130 can have a boiling point greater than 180 degrees Celsius (such as at 760 mm Hg). The coating material can have a density between 2 g/cc and 5 g/cc (such as at 25 degrees Celsius). Coating material 130 can have 2.5 g/cc One density between 4g/cc. The coating material can have a density between 3 g/cc and 3.5 g/cc.

In some embodiments, the coating material 130 can include diiodomethane. Coating material 130 can include a gem refractometer liquid. The coating material 130 can maintain fluid properties during laser processing. Coating material 130 can include a leveling composition. Preferably, the coating material 130 is easily removed from the rough surface after the laser treatment. The coating material 130 may be cleaned from the rough surface by a combination of acetone, carbon tetrachloride, diethyl ether, dichloromethane, toluene, xylene or the like, or the coating material 130 may be washed from the rough surface by water, or may be borrowed The coating material 130 is cleaned from the rough surface by ethanol.

The cover 150 is transparent to the laser wavelength. The outer cover 150 can include a substrate material. The outer cover 150 can include a smooth outer cover surface that is non-reflective at this wavelength. The outer cover 150 can include a glass. The cover 150 may comprise a sapphire, diamond, enamel or plastic.

Such a rough surface mitigation technique is described in U.S. Provisional Patent Application Serial No. 61/912,192, the disclosure of which is incorporated herein by reference.

Although the 2DID code has been described above by way of example, those skilled in the art will appreciate that by utilizing depth control for marking the transparent substrate 44, a 3D code employing point 32 can be constructed.

Although point 32 is not visible to the human eye or is internal to substrate 44, an optical indicia reader 220 can be designed to read point 32 and decode the 2DID code. 9 through 15 show a simplified partial schematic side view of some of the components of an exemplary optical indicia reader 220a through 220g (generally, optical indicia reader 220) adapted to read a modified point 32 of a 2DID code. view.

Referring to FIG. 9, an exemplary optical indicia reader 220a employs a light source 222 and an imaging microscope system including a video microscope unit 234. In some embodiments, light source 222 can be positioned to propagate light 226 along an illumination path that traverses bottom surface 106, and imager 228 And optics 230 are positioned along an imaging path operable to receive one of the rays 226a emitted from the upper surface 104. In some particular embodiments, light source 222 and a camera 224 can be positioned on opposite sides of workpiece 46 such that light 226 emitted from light source 222 passes through substrate 44 to reach imager 228 of one of cameras 224. In some embodiments, the illumination path traverses the lower surface 106 at a vertical angle. In some embodiments, light source 222 is positioned along an illumination axis that is substantially perpendicular to a first surface of substrate 44. In some embodiments, imager 228 is positioned along an imaging axis that is substantially perpendicular to an upper surface of substrate 44. In some embodiments, the illumination axis and the imaging axis are parallel. In some embodiments, the illumination axis and the imaging axis are collinear.

In some particular embodiments, if a mirror (not shown) is used, the light source 222 and camera 224 can be positioned on the same side of the workpiece 46 even when the light 226 emitted from the source 222 passes through the substrate 44 to reach an imager 228. on. For example, light source 222 can be positioned to propagate light 226 along an illumination path that traverses bottom surface 106, and the mirror is operative to receive light 226a emitted from upper surface 104 and to reflect light 226a to an imager 228 An imaging path is positioned and the optic 230 is positioned at an elevation below the bottom surface 106 (without necessarily illuminating the light 226a through the workpiece 46 a second time). Moreover, some embodiments rely on the reflection of light 226, in which case light source 222 and camera 224 can be positioned substantially on the same side of workpiece 46.

Light source 222 can be of virtually any kind that is paired with cooperating (microscope) optics 230 and imager 228. In some embodiments, light source 222 emits monochromatic light to remove some of the potential adverse effects of chromatic aberration. In some embodiments, the light source 222 can be gated at high intensity, such as within a short time interval (such as milliseconds or tens of milliseconds, greater than or equal to ten times the steady state). In some embodiments, the light source 222 is a light emitting diode (LED) or a group of LEDs, such as an array of LEDs. LEDs are less expensive and exhibit many of the desirable properties for lighting applications associated with the techniques disclosed herein.

In some embodiments, such as in the relative positioning of the components shown in FIG. 9, the light source 222 is along an axis that is substantially perpendicular to the bottom surface 106 of the substrate 44 and substantially perpendicular to the image plane of the imager 228 (not shown) ) Positioning. In some embodiments, the light source 222 is positioned along a first axis that is substantially perpendicular to the bottom surface 106 of the substrate 44 and parallel to a second axis that is substantially perpendicular to the image plane of the imager 228 such that the light source 222 is positioned. There is an angle of incidence with respect to imager 228. In some embodiments, light source 222 is positioned along a second axis that is substantially perpendicular to imager 228 but at an angle of incidence relative to imager 228.

Light source 222 can emit light 226 including any suitable wavelength. Exemplary suitable visible wavelengths for light source 222 can include, but are not limited to, one or more of the following wavelengths: 660 nm, 635 nm, 633 nm, 623 nm, 612 nm, 592 nm, 585 nm, 574 nm, 570 nm, 565 nm, 560 nm, 555 nm, 525 nm, 505 nm, 470 nm, and 430 nm. These wavelengths can be used individually or in combination. In some exemplary embodiments that include a prototype, a red wavelength (such as 635 nm) has been employed. Invisible wavelengths (such as those in the UV range or the IR range) may alternatively or additionally be employed.

In some embodiments, light source 222 can include a multi-spectral emission source. If only one or more particular wavelengths are to be imaged, one or more wavelength filters may be employed to block undesired wavelengths, or one or more monochrome cameras 224 may be employed to limit data extraction to (several) specific wavelengths. .

In some embodiments, light source 222 can include an emission source that emits different specific wavelengths. In some embodiments, when a particular plurality of wavelengths are employed, especially in the based on substrate 44 In the case where the colorimetric properties of the foreign matter or impurities are selected, a monochrome camera 224 can be employed to enhance the contrast determination. Exemplary emission wavelengths can include a red, blue, and green emission scheme; a red, infrared, and green emission scheme; or a red, infrared, blue, and green emission scheme. However, other launching schemes may be employed.

Contrast analysis can be performed using the techniques disclosed in U.S. Patent No. 7,589,869, the disclosure of which is incorporated herein by reference in its entirety in its entirety herein in The method of image quality in images. A contrast optimization algorithm determines which particular wavelength of the available wavelengths is best suited to maximize contrast. The quality of the image can be further improved by active noise removal by deciding to provide a maximum and minimum contrast between the target and a background. The image texture data (ie, noise) is then eliminated by, for example, dividing the maximum contrast image by the pixel-by-pixel division of the minimum contrast image. Alternatively, images obtained using at least two wavelengths (or image data therefrom) may be combined algebraically for noise reduction. The resulting synthetic image data can be fed to any known target recognition algorithm.

Camera 224 can be of almost any kind that is paired with cooperating optics 230 and light source 222. As previously discussed, camera 224 can be full color, monochrome, or selected for a plurality of particular wavelengths. It will be appreciated that a selectable wavelength selective filter (not shown) may be employed closer to camera 224 or light source 222, or an alternative wavelength selective filter may be placed proximate to both camera 224 and light source 222.

The exemplary imager 228 includes a VGA imager (CCD or CMOS) having one resolution of 688 x 488, 1032 x 776, 1288 x 946, 1280 x 1024, 1384 x 1032, 1624 x 1224, or 2448 x 2048 pixels. However, other suitable formats with multiple resolutions can be used. When the type of imager 228. An exemplary embodiment of one of the prototypes of an optical indicia reader 220 utilizes a Flea® 2 camera from Point Grey Research, Inc. of Richmond, British Columbia, Canada.

Optical device 230 can include one or more lenses 232. Lens 232 can comprise a distinct lens sheet or can be a single composite lens sheet. Exemplary optics 230 provides from 2x to 50x magnification. In some embodiments, optical device 230 provides greater than or equal to 5 times magnification. In some embodiments, optical device 230 provides greater than or equal to 10 times magnification. In some embodiments, optical device 230 provides greater than or equal to 5 times magnification and less than or equal to 20 times magnification. In many embodiments, optical device 230 includes an objective lens 232. One exemplary embodiment of one of the optical indicia readers 220 employs a 10x(R) corrected flat field achromatic objective lens (flat field apochromatic infinitely corrected long working distance objective) from Mitutoyo America, Inc. of Aurora, Ill. In some embodiments, optics 230 and camera 224 are assembled in a microscope unit 234. One prototype of an exemplary video microscope unit 234 that employs a camera 224 and optics 230 includes a Visual Microscope Unit (VMU) from Mitutoyo America, Inc. of Aurora, Ill.

An exemplary range of depth of field for optics 230 is about +/- 50 [mu]m. In some embodiments, such as when 5x magnification is employed, the depth of field for optics 230 ranges from about +/- 10 [mu]m. In some embodiments, such as when 10x magnification is employed, the depth of field for optics 230 ranges from about +/- 2.5 [mu]m.

An exemplary range of field of view (FOV) for imager 228 (in combination with optics 230) is from about 500 [mu]m to about 1.2 mm. In some embodiments, such as when 5x magnification is employed, the range for the field of view is greater than or equal to about 1 mm. In some embodiments, For example, when using 5x magnification, the range for the field of view is greater than or equal to about 1.5 mm.

In some embodiments, such as when 10x magnification is employed, the range for the field of view is greater than or equal to about 500 [mu]m. In some embodiments, such as when 10x magnification is employed, the range for the field of view is greater than or equal to about 800 [mu]m. In some embodiments, such as when 5x magnification is employed, the range for the field of view is greater than or equal to about 800 [mu]m. In some embodiments, such as when 10x magnification is employed, the range for the field of view is less than or equal to about 800 [mu]m.

The ISO standard requires that the minimum x and y dimensions of a field size of a 2DID code be greater than or equal to 255 μm. Optics 230 provides the ability to reliably read 2DID codes having a field size that has a side dimension of less than 500 microns. In some embodiments, optics 230 provides the ability to reliably read a 2DID code having a field size that has a side dimension of less than 250 microns. In some embodiments, such as with one of the objective lenses 232 providing 10x magnification, the optics 230 provides the ability to reliably read a 2DID code having a field size that has a side dimension of less than 125 microns.

In some embodiments, optics 230 provides the ability to reliably read 2DID codes having a field size of two sizes less than 250 microns. In some embodiments, optics 230 provides the ability to reliably read 2DID codes having a field size of two sizes less than 125 microns.

In some embodiments, the microscopy unit 234 is capable of achieving a modulation transfer function (MTF) of greater than 50 line pairs per millimeter. In some embodiments, the microscopy unit 234 is capable of achieving an MTF of greater than 75 line pairs per millimeter. In some embodiments, the microscopy unit 234 can achieve an MTF of greater than 80 line pairs/mm. In some embodiments, the microscopy unit 234 is capable of achieving an MTF of greater than 90 line pairs/mm. In some embodiments, the microscopy unit 234 can achieve greater than 100 One line pair / mm one MTF. In some embodiments, the microscopy unit 234 can achieve an MTF of greater than 125 line pairs/mm.

Referring again to FIG. 9, optical indicia reader 220a can employ a diffuser 240 positioned between source 222 and substrate 44. Light ray 226 emitted from light source 222 is diffused by diffuser 240 and propagates into substrate 44. Some of the rays 226a pass between points 32 that form a segment of the data point (group 30 or square) of the 2DID code. These rays 226a arrive at the imager 228 of the camera 224. Some of the light 226b is intercepted by the point 32 and attenuated and spread. Due to the scattering of light 226b propagating into substrate 44, point 32 causes a local increase in apparent optical density. Light 226b does not reach imager 228 of camera 224. Thus, point 32 looks like a black shade against a light background.

The embodiment described with respect to FIG. 9 is particularly useful for reliably reading a point 32 in a polishing substrate 44 that has one of surfaces 104 and 106 that are effectively transparent to the wavelength(s) of light 226.

Figure 10 shows a partial schematic side view of some of the components of another exemplary optical indicia reader 220b adapted to read a modified point 32 of a 2DID code. Many of the components depicted in FIG. 10 have functions similar to the corresponding components depicted in FIG. 9 and have been provided with corresponding reference numerals regardless of whether the particular components are identical or may be different. Referring to FIG. 10, the video microscope unit 234 employs an elongate tube that houses a tube lens 242 optically positioned between the imager 228 and the objective lens 232 of the optics 230.

The embodiment described with respect to FIG. 10 can also be particularly useful for reliably reading a point 32 in a substrate 44 that has a surface 42 that is effectively transparent to the wavelength(s) of the ray 226.

Figure 11 shows another illustrative point of point 32 suitable for reading a modified 2DID code. A partially schematic side view of one of some of the components of optical indicia reader 220c. Many of the components depicted in Figure 11 have functions similar to the corresponding components depicted in Figure 9 and have been provided with corresponding reference numerals regardless of whether the particular components are identical or may be different. Referring to Figure 11, the workpiece 46 can be an unpolished workpiece 46, such as the wafer 100 shown in Figure 8. In particular, the unpolished workpiece 46 may have one or more surfaces 104 and 106 that are rough or may be chopped at a surface deviation of, for example, about +/- 5 microns. Surfaces 104 and 106 having a rough surface texture may obscure or otherwise adversely affect the image of the shadow of subsurface point 32.

Thus, referring to FIG. 8 and its description, one or both surfaces 104 and 106 of workpiece 46 of FIG. 11 may be covered with an index matching fluid 130 to mitigate surface variations in surfaces 104 and 106. Moreover, a smooth outer cover 150 can also be used to cover the index matching fluid 130.

The index matching fluid 130 and the outer cover 150 reduce the adverse effects of the surfaces 104 and 106 having a rough surface texture such that the imager 228 can accurately discern the shadows produced by the dots 32.

Figure 12 shows a partial schematic side view of some of the components of another exemplary optical indicia reader 220d adapted to read a modified point 32 of a 2DID code. Many of the components depicted in Figure 12 have functions similar to the corresponding components depicted in Figure 9 and have been provided with corresponding reference numerals regardless of whether the particular components are identical or may be different. Referring to Figure 12, workpiece 46 has a substrate 44 having a black opaque bottom surface 106. In some embodiments, the substrate 44 is transparent and the bottom surface 106 is coated with a black or light absorbing material. The light absorbing material can be selected to be absorptive to the emission wavelength(s) of the selected source 222 and/or the source can be selected to provide an emission wavelength(s) in a range absorbed by the bottom surface 106 or its coating. .

In FIG. 12, light source 222 and imager 228 are respectively positioned to be on substrate 44. Light is directed at the same (upper) surface 104 and receives light from the same (upper) surface 104 of the substrate 44. In particular, light source 222 is positioned to propagate light 226 along an illumination path that traverses upper surface 104, and imager 228 and optics 230 are positioned along an imaging path that traverses the upper surface and are operable to receive propagation through Light 226c on upper surface 104. In some embodiments, light source 222 directs light 226 to upper surface 104 of substrate 44 at a non-normal incidence angle. In some embodiments, light source 222 has an illumination axis that has one of the angles of incidence between 1 and 70 degrees. In some embodiments, the illumination axis of light source 222 has an angle of incidence between 10 degrees and 65 degrees. In some embodiments, the illumination axis of light source 222 has an angle of incidence of less than or equal to 60 degrees.

Referring again to FIG. 12, light ray 226 can be directed through a focusing lens 250 for propagation into substrate 44. Some of the light 226c intersects the point 32 and is reflected to impinge on the imager 228. Some of the light 226d passes between the dots 32 and is absorbed by the black bottom surface 106 of the substrate 44 or its wavelength selective absorbing coating. For imager 228, point 32 appears as a bright mark against a black background. Contrast inversion in machine vision software (eg, light to black and vice versa) and feature enhancement algorithms generate a reliably readable based on points 32 of which each group 30 represents a data point (or square) Take the 2DID pattern. Point 32 looks like a bright mark against a black background.

Figure 13 shows a partial schematic side view of some of the components of another exemplary optical indicia reader 220e adapted to read a modified point 32 of a 2DID code. Many of the components depicted in Figure 13 have functions similar to the corresponding components depicted in Figure 12 and have been provided with corresponding reference numerals regardless of whether the particular components are identical or may be different. Referring to Figure 13, the video microscope unit 234 employs an elongate tube that houses a tube lens 242 optically positioned between the imager 228 and the objective 232 of the optic 230. With respect to optical indicia reader 220d, optical indicia reader 220e is adapted to read a dot 32 in substrate 44 having a black or black coated bottom surface 106.

14 shows a side view of some of the components of another exemplary optical indicia reader 220f adapted to read a modified point 32 of a 2DID code, and FIG. 15 shows an enlarged portion of FIG. Many of the components depicted in Figure 14 have functions similar to those depicted in Figure 13 and have been provided with corresponding reference numerals regardless of whether the particular components are identical or may be different or may be located at different relative positions or orientations.

Referring to Figure 14, workpiece 46 has a substrate 44 having a light colored, white or off-white opaque bottom surface 106. In some embodiments, substrate 44 is transparent and bottom surface 106 is coated with a light colored or reflective material. The reflective material can be selected to be reflective to the emission wavelength(s) of the selected source 222 and/or the source can be selected to provide an emission wavelength(s) in a range that is reflected by the bottom surface 106 or its coating.

In the exemplary optical indicia reader 220f shown in FIG. 14, one of the imaging units 236 of the microscope unit 234 additionally houses a tube linear polarizer 260 positioned along the image path between the imager 228 and the tube lens 242. . In some embodiments, tube lens 242 and objective lens 232 cooperate to define a collimating space 264 therebetween. The microscope unit 234 also houses a beam splitter 262 that is positioned along the image path in the collimating space 264 between the tube lens and the objective lens 232 of the optic 230. In some embodiments, the objective lens 232 defines a focal length F _OBJ relative to the location of the point 32. Beam splitter 262 allows some of the light 226 reflected from opaque bottom surface 106 to propagate along tube path toward tube linear polarizer 260 and imager 228.

The exemplary optical indicia reader 220f also takes an illumination catheter 270 that can be oriented parallel to the imaging tube 236 of the microscope unit 234 as shown in FIG. It will be appreciated that the illumination catheter 270 can be oriented to be perpendicular to the imaging tube 236, or the like, can have one of an orientations that alternate with one another, and can then be accommodated by one or more illumination path mirrors 272.

The illumination conduit 270 can be adapted to receive or support an illumination system 274 that includes a light source 222, one or more collimating lenses 278, and an aperture 280. The collimating lens 278 is positioned along the illumination path between the source 222 and the workpiece 46, and the aperture is positioned along the illumination path between the source 222 and the collimating lens 278. In some embodiments, the aperture 280 defines a distance F _L1 relative to the position of the collimating lens 278. The aperture 280 can have a major spatial axis or diameter as a function of focal length F _OBJ and distance F _L1 . In some embodiments, the diameter of the aperture 280 or a function of the primary spatial axis system F _L1 /F _OBJ . Alternatively, the focal length F _OBJ and the distance F _L1 can be adjusted as a function of the diameter of the aperture 280 or the main spatial axis.

In some embodiments, illumination conduit 270 or illumination system 274 also includes a catheter linear polarizer 282 that is positionable along an illumination path between collimating lens 278 and workpiece 46. Catheter linear polarizer 282 and/or light source 222 can be rotated about the axis of the illumination path to enhance image contrast.

Illumination conduit 270 can also include a catheter adapter 286 that changes the diameter of the illumination conduit from one diameter to the other, such as from a smaller diameter to a larger diameter. One of the illumination segments 270 that intersect the imaging tube 236 can have a diameter that is the same as the diameter of the imaging tube 236.

In the exemplary embodiment shown in FIG. 14, some of the light rays 226 emitted by the light source 222 propagate through the apertures 280 along the illumination path. This aperture ray 226g propagates through the collimating lens 278. These collimated rays 226h can propagate through the optional conduit linear polarizer. This collimated (and polarized) ray 226h can be reflected by one of the plurality of mirrors 270 to intersect the beam splitter 262, which causes the rays 226h to be reflected by the objective 232 toward the workpiece 46.

Referring to Figures 14 and 15, the objective lens provides focused light 226i, which is reflected off The bottom surface 106 and propagates as a ray 226a toward the point 32. Some of the rays 226a pass between points 32 that form a segment of the data point (group 30 or square) of the 2DID code. These rays 226a arrive at the imager 228 of the camera 224. Some of the light 226b is intercepted by the point 32 and attenuated and spread. As described with respect to the embodiment shown in Figure 9, point 32 appears to be a black shade against a light background.

With regard to all described exemplary embodiments, it will be appreciated that one or more components of workpiece 46 and optical code reader 220, such as imager 228, may all be stationary during inspection of point 32. The workpiece 46 can be placed into an inspection position by a conveyor, a chuck or other transport mechanism. In an exemplary embodiment, the workpiece 46 will remain stationary on the X-axis, Y-axis, and Z-axis, and one or more of the optical components of the microscope unit 234 will move over the Z-axis to auto focus.

However, the workpiece 46 can be in motion while verifying that the optical 2DID code or one or more components of the optical code reader 220 can be in motion while verifying the optical 2DID code. This movement can include X or Y movements and/or Z movements (which can be focused on related). However, both the workpiece 46 and one or more components of the optical code reader 220 can be in motion while verifying the optical 2DID code.

In some embodiments in which motion and code inspection are concurrent, light source 22 is optional to prevent blurring. For example, in an exemplary embodiment, point 32 has a diameter of about 2 microns and X/Y motion can be maintained within a quarter of the diameter, such as about 0.5 microns. If the depth of the video microscope unit 234 is about 5 microns, the desired gating may require a sufficiently short pulse of light to maintain an image of the point 32 (or 2DID code) within about 1.25 microns. Since DD = V / T, the gate time interval will be inversely proportional to the speed.

In some embodiments, an optical tag reader is employed to decode a 2DID code (eg, For example, one of the GS1 data matrices can be purchased as a standard software package. In some embodiments, the standard software package is enhanced by image and contrast enhancement techniques such as those described in U.S. Patent No. 7,589,869.

In some alternative, additional or cumulative embodiments, the standard software suite is enhanced by a technique for determining the correlation of the group 30 of points 32 with the data points (black squares). In some embodiments, the enhanced or adapted software may be provided under the criteria for group 32 of points 32 and/or points 32. The criteria can be similar to the criteria used for selection and group formation as previously discussed. This criterion may include, but is not limited to, one or more of the following: a spatial principal of point 32, a distance between points 32, a distance between groups 30 of points 32, whether point 32 is more than a group The indication of the member of 30, the size of the group 30, the approximate location of the particular point 32 or group 30, and the depth of the point 32 within the substrate 44. Such values may be associated with, for example, respective representations of a 2DID code and stored in a lookup table. The software or lookup table may also include accuracy and other characteristics based on the laser micromachining system 40 used to make the dots. Acceptable deviation information.

Thus, optical tag reader 220 can read point 32 and determine which group 30 (and data points or squares) it belongs to and then decode the 2DID pattern represented by group 30 of points. It will be appreciated that the software may also ignore defects or imperfections that may occur in the substrate 44 because such defects are statistically impossible to meet the criteria of point 32 or the point 32 within the group 30 established by the intended point 32. Relative or absolute position.

The above embodiments of the invention are not to be construed as limiting the invention. While a few specific example embodiments have been described, it will be apparent to those skilled in the art that

Accordingly, all such modifications are intended to be included within the scope of the invention as defined in the scope of the claims. For example, the skilled person will understand that the subject matter of any sentence or paragraph may be combined with some or all of the other sentences or paragraphs unless such combinations are mutually exclusive.

It will be apparent to those skilled in the art that many changes in the details of the embodiments described above may be made without departing from the basic principles of the invention. Therefore, the scope of the invention should be determined by the scope of the following claims, in which

32‧‧‧ points

44‧‧‧Substrate

46‧‧‧Workpiece

104‧‧‧ Surface

106‧‧‧ surface

220a‧‧‧Optical Marker Reader

222‧‧‧Light source

224‧‧‧ camera

226‧‧‧Light

226a‧‧‧Light

226b‧‧‧ line

228‧‧‧ Imager

230‧‧‧Optical devices

232‧‧‧ lens

234‧‧•Video microscope unit/micro unit

240‧‧‧Diffuser

Claims (106)

A method for reading a two-dimensional identification code in a substrate having one of first and second opposing surfaces, the method comprising: directing light toward a first surface of the substrate, wherein the light has a wavelength, And wherein the substrate is transparent to the wavelength, wherein the two-dimensional code is represented by a dot spread in the substrate, wherein the dot spreads a plurality of points including a group, the points of the groups include the first group and the second group a point, wherein each of the points of the first and second groups represents a geometric shape such that the points are interspersed to form an array of multiple columns and a plurality of rows of geometric regions, wherein some of the geometric regions comprise a group Point and some of the geometric regions lack points, wherein a first portion of the light is blocked by the dots, and wherein a second portion of the light passes through the second surface beyond the points and propagates through the substrate; Amplifying the second portion of the light propagating through the second surface of the substrate; imaging the second portion of the light propagating through the second surface of the substrate and amplifying the image by an imager; analyzing the light One of the second part of the image and The first portion of the barrier of light causes the shadow to determine the spread of such point; and the two-dimensional code is determined based on the spread of such a point of the image of the imager. The method of claim 1, wherein the representative geometry is a rectangular geometry, and wherein the points of the first and second groups are positioned to represent a corner of the rectangular geometry. The method of claim 1, wherein the points of the first and second groups each comprise an odd number of points. The method of claim 1, wherein the point indicating the two-dimensional code is invisible to the human eye at a distance greater than or equal to 25 mm from a human eye. The method of claim 1, wherein the array has an array size of greater than 50 microns. The method of claim 1, wherein the array has an array size of less than 500 microns. The method of claim 1, wherein the array has an array size of less than or equal to 250 microns. The method of claim 1, wherein the points of the first and second groups are invisible to the human eye at a distance greater than or equal to 25 mm from the human eye. The method of claim 1, wherein the points of the first and second groups are invisible to the human eye at a distance greater than or equal to 25 mm from the human eye. The method of claim 1, wherein the points of the first and second groups each have a size of one of the main spatial axes of less than 35 microns. The method of claim 1, wherein the points each have a size of one of the main spatial axes, and wherein the points are separated by a distance greater than or equal to four times the size of the main spatial axis. The method of claim 1, wherein the geometric regions represent squares in a QR code. The method of claim 1, wherein each point is formed by a laser pulse. The method of claim 1, wherein the dots are black and the substrate is light colored. The method of claim 1, wherein the dots are black and wherein the substrate is substantially It is transparent to visible light. The method of claim 1, wherein the substrate comprises a crystalline material. The method of claim 1, wherein the substrate comprises sapphire. The method of claim 1, wherein the substrate comprises glass. The method of claim 1, wherein the substrate comprises a plastic. The method of claim 1, wherein the substrate comprises aluminum. The method of claim 1, wherein the substrate comprises an amorphous material. The method of claim 1, wherein a beam positioning system and a substrate support system cooperate to position the laser pulses relative to a position on the substrate, and wherein the points are positioned accurately Sex is better than 5 microns. The method of claim 1, wherein a beam positioning system and a substrate support system cooperate to position the laser pulses relative to a position on the substrate, and wherein the points are positioned accurately Sex is worse than 5 microns. The method of claim 23, wherein a beam positioning system and a substrate support system cooperate to position the points of the laser pulses relative to a position on the substrate, and wherein the points are positioned accurately Sex is worse than 10 microns. The method of claim 1, wherein the point of the group provides a signal to noise ratio greater than or equal to 5. The method of claim 1, wherein the point of the group provides a signal-to-noise ratio greater than or equal to 10. The method of claim 1, wherein the point of the group provides a signal-to-noise ratio greater than or equal to 100. The method of claim 1, wherein the software is used to convert the points of the groups into black squares of the two-dimensional code. The method of claim 1, wherein the array comprises at least 50 geometric regions in a column or row. The method of claim 1, wherein each point has a point area, wherein a cumulative point area represents a point area of the points within a group of points, wherein the points in a group are scattered in a group The area is expanded, wherein the cumulative point area is less than or equal to less than 5% of the group area. A method as claimed in any of the preceding claims, wherein the step of amplifying employs an optical system capable of achieving a modulation transfer function of greater than 80 line pairs/mm. The method of claim 2, wherein the method of claim 2, and the method of claim 31, which are subject to the exclusion of the subject matter. An optical code reader comprising: a light source for illuminating a workpiece having a substrate, wherein the light has a wavelength, wherein the light is operable for guiding at the substrate, wherein the substrate Transparent to the wavelength of the light, and wherein the substrate has first and second surfaces remote from each other; an optical system; an imager for receiving light propagating through the substrate or for receiving by the a light reflected between one or a second surface embedded in the substrate; a first electronic circuit for analyzing an image of the light to determine the spread of the dots; and a second electronic circuit Determining the two based on the dispersion of the points imaged by the imager Dimension code. An optical code reader as claimed in claim 33, wherein the light source is positioned to propagate the light along an illumination path traversing the first surface, and wherein the imager and the optical system are operable to An imaging path location of the light reflected from the second surface is received. An optical code reader as claimed in claim 34, wherein the first electronic circuit analyzes a shadow caused by blocking the light by a dot. An optical code reader as claimed in claim 33, wherein the light source is positioned to propagate the light along an illumination path traversing the first surface, and wherein the imagers and optical systems traverse the The first surface is operative to receive an imaging path of the light propagating through the first surface. The optical code reader of claim 36, wherein the points are at least partially reflective to the light, wherein the second surface or a layer thereon is at least partially absorptive to the light, and wherein the first An electronic circuit analyzes the light reflected from the points. The optical code reader of claim 36, wherein the points are at least partially absorbable to the light, wherein the second surface or a layer thereon is at least partially reflective to the light, and wherein the An electronic circuit analyzes the shadow caused by blocking the light by the points. The optical code reader of claim 33, wherein the two-dimensional code is represented by a dot spread in the substrate, wherein the dot spreads a plurality of points including a group, and the points of the groups include the first a point of the second group, wherein each of the points of the first and second groups represents a geometric shape such that the points are interspersed to form an array of multiple columns and rows of geometric regions, wherein some of the geometric regions A point containing a group and some of the geometric regions are missing points. An optical code reader as claimed in claim 33, wherein the illumination path is transverse to a vertical angle Wear the first surface. The optical code reader of claim 33, wherein the light source is positioned along an illumination axis that is substantially perpendicular to the first surface of the substrate. An optical code reader as claimed in claim 33, wherein the imager is positioned along the illumination axis. An optical code reader as in claim 33, wherein the light source is positioned along an illumination axis having an incidence angle that is not perpendicular to the first surface of the substrate. An optical code reader as claimed in claim 43 wherein the illumination axis has an angle of incidence between 1 and 70 degrees. An optical code reader as claimed in claim 43 wherein the illumination axis has an angle of incidence between 10 and 65 degrees. The optical code reader of claim 43, wherein the illumination axis has an incident angle of less than or equal to 60 degrees. An optical code reader as in claim 33, wherein the imager is positioned along an imaging axis that is perpendicular to the first surface. An optical code reader as claimed in claim 33, wherein the light source comprises an LED. An optical code reader as claimed in claim 33, wherein the light source provides a visible wavelength. The optical code reader of claim 33, wherein the light source provides one or more of the following wavelengths: 660 nm, 635 nm, 633 nm, 623 nm, 612 nm, 592 nm, 585 nm, 574 nm, 570 nm, 565 nm, 560 nm, 555 nm , 525 nm, 505 nm, 470 nm, and 430 nm. An optical code reader as claimed in claim 33, wherein the light source provides a red wavelength. An optical code reader as claimed in claim 33, wherein the imager is monochrome. An optical code reader as claimed in claim 33, wherein the imager is full color. An optical code reader as claimed in claim 33, wherein the optical system employs an optical device that provides a magnification from 2 to 50 times. An optical code reader as claimed in claim 33, wherein the optical system employs an optical device that provides greater than 5 times magnification. An optical code reader as claimed in claim 33, wherein the optical system employs an optical device that provides greater than 10 times magnification. An optical code reader as claimed in claim 33, wherein the optical system employs an optical device that is less than 20 times magnified. An optical code reader as claimed in claim 33, wherein the optical code reader has a modulation transfer function of greater than 50 line pairs/mm. An optical code reader as claimed in claim 33, wherein the optical code reader has a modulation transfer function of greater than 75 line pairs/mm. An optical code reader as claimed in claim 33, wherein the optical code reader has a modulation transfer function of greater than 80 line pairs/mm. An optical code reader as claimed in claim 33, wherein the optical system provides a depth of field of about +/- 50 μm. An optical code reader as claimed in claim 33, wherein the optical system provides a depth of field of about +/- 10 μm. An optical code reader as claimed in claim 33, wherein the optical system provides a depth of field of about +/- 2.5 μm. An optical code reader as claimed in claim 33, wherein the optical system provides a field of view greater than or equal to about 500 [mu]m. An optical code reader as claimed in claim 33, wherein the optical system provides a field of view greater than or equal to about 800 μm. An optical code reader as claimed in claim 33, wherein the optical system provides a field of view less than or equal to about 800 μm. An optical code reader as in claim 33, wherein the dots form a 2DID code having a field size having a side dimension of less than 500 microns. An optical code reader as claimed in claim 33, wherein the dots form a 2DID code having a field size having a side dimension of less than 250 microns. An optical code reader as in claim 33, wherein the dots form a GS1 DataMatrix code having a field size having a side dimension of less than 125 microns. An optical code reader as claimed in claim 33, wherein the dots form a GS1 DataMatrix code having a field size of two sizes less than 250 microns. An optical code reader as in claim 33, wherein the dots form a GS1 DataMatrix code having a field size of two sizes less than 125 microns. The optical code reader of claim 39, wherein the representative geometric shape is a rectangular geometric shape, and wherein the points of the first and second groups are positioned to represent a corner of the rectangular geometric shape . An optical code reader as claimed in claim 39, wherein the points of the first and second groups each comprise an odd number of points. An optical code reader as claimed in claim 39, wherein the point of the two-dimensional code is dispersed It is invisible to the human eye at a distance greater than or equal to 25 mm from one eye. An optical code reader as in claim 39, wherein the array has an array size greater than 50 microns. An optical code reader as in claim 39, wherein the array has an array size of less than 500 microns. An optical code reader as in claim 39, wherein the array has an array size of less than or equal to 250 microns. An optical code reader as claimed in claim 39, wherein the points of the first and second groups are invisible to the human eye at a distance greater than or equal to 25 mm from the human eye. An optical code reader as claimed in claim 39, wherein the points of the first and second groups are invisible to the human eye at a distance greater than or equal to 25 mm from the human eye. An optical code reader as claimed in claim 39, wherein the points of the first and second groups each have a size of one of the main spatial axes of less than 35 microns. An optical code reader as claimed in claim 39, wherein the points each have a size of one of the main spatial axes, and wherein the points are separated by a factor greater than or equal to four times the size of the main spatial axis distance. An optical code reader as claimed in claim 39, wherein the geometric regions represent squares in a QR code. An optical code reader as claimed in claim 33, wherein each point is formed by a laser pulse. An optical code reader as claimed in claim 33, wherein each point is formed by a plurality of laser pulses. An optical code reader as claimed in claim 39, wherein the dots are black and the substrate is Light color. An optical code reader as in claim 39, wherein the dots are black and wherein the substrate is substantially transparent to visible light. An optical code reader as claimed in claim 33, wherein the substrate comprises a crystalline material. An optical code reader as claimed in claim 33, wherein the substrate comprises sapphire. An optical code reader as claimed in claim 33, wherein the substrate comprises glass. The optical code reader of claim 33, wherein the substrate comprises a plastic. An optical code reader as claimed in claim 33, wherein the substrate comprises aluminum. An optical code reader as claimed in claim 33, wherein the substrate comprises an amorphous material. An optical code reader according to claim 33, wherein a beam positioning system and a substrate supporting system cooperate to position the laser pulses with respect to a position on the substrate, and wherein the points are The positioning accuracy of the position is better than 5 microns. An optical code reader according to claim 33, wherein a beam positioning system and a substrate supporting system cooperate to position the laser pulses with respect to a position on the substrate, and wherein the points are The location accuracy of the location is worse than 5 microns. An optical code reader according to claim 39, wherein a beam positioning system and a substrate supporting system cooperate to position the laser pulses with respect to a position on the substrate, and wherein the points are The positioning accuracy of the position is worse than 10 microns. An optical code reader as claimed in claim 39, wherein the point of the group provides a signal to noise ratio greater than or equal to 5. An optical code reader as claimed in claim 39, wherein the point of the group provides a signal to noise ratio greater than or equal to 10. An optical code reader as claimed in claim 39, wherein the point of the group provides a signal to noise ratio greater than or equal to 100. An optical code reader as claimed in claim 39, wherein the software is used to convert the points of the groups into black squares of the two-dimensional code. An optical code reader as in claim 39, wherein the array comprises at least 50 geometric regions in a column or row. An optical code reader as claimed in claim 39, wherein each point has a point area, wherein a cumulative point area represents a point area of the points within a group of points, wherein the point in a group is dispersed Expanding over a group of areas, wherein the cumulative point area is less than or equal to less than 5% of the group area. The optical code reading of any one of the patent application scope No. 33 to the patent application scope No. 101, which is not subject to the mutually exclusive subject matter, is attached to any one of the application patents, the scope of claim 33, Device. A method for reading a two-dimensional identification code in a substrate having one of a first and a second opposing surface, the method comprising: directing light toward the first surface of the substrate, wherein the light has a wavelength, And wherein the substrate and the first surface thereof are transparent to the wavelength, wherein the two-dimensional code is represented by a dot spread in the substrate, wherein the dot spreads a plurality of groups, the points of the group include the first a point of the second group, wherein each of the points of the first and second groups represents a geometric shape such that the points are interspersed to form an array of multiple columns and rows of geometric regions, wherein some of the geometric regions a point comprising a group and some of the geometric regions lacking a point, wherein a first portion of the light passes beyond the point and is absorbed at the second surface, wherein the second surface is applied thereto a coating is absorptive to the wavelength, and wherein a second portion of the light passes through the second surface beyond the point and propagates through the first surface; the amplification propagates through the first surface a second portion of the light; imaging the second portion of the light that propagates through the first surface and magnifying with an imager; analyzing an image of the second portion of the light and the first portion of the light Absorption causes a black background to determine the spread of the points; and the two-dimensional code is determined based on the spread of the points imaged by the imager. The method of any one of the claims of claim 103, and the method of claim 2, and the method of claim 32, wherein the method of claim 32 is applied. A method for reading a two-dimensional identification code in a substrate having one of a first and a second opposing surface, the method comprising: directing light toward the first surface of the substrate, wherein the light has a wavelength, And wherein the substrate and the first surface thereof are transparent to the wavelength, wherein the two-dimensional code is represented by a dot spread in the substrate, wherein the dot spreads a plurality of groups, the points of the group include the first a point of the second group, wherein each of the points of the first and second groups represents a geometric shape such that the points are interspersed to form an array of multiple columns and rows of geometric regions, wherein some of the geometric regions a point comprising a group and some of the geometric regions lacking a point, wherein some of the light passes beyond the points and becomes reflected light by the second surface, wherein the second surface is applied to One of the coatings is absorptive to the wavelength, wherein a first portion of the reflected light is blocked by the points and wherein a second portion of the reflected light passes through the first surface beyond the point and propagates through the substrate Amplifying and propagating through the first surface The second portion of the reflected light; Imaging the second portion of the reflected light through the second surface of the substrate by an imager; analyzing an image of the second portion of the reflected light and blocking the first portion of the reflected light Causing a shadow to determine the spread of the points; and determining the two-dimensional code based on the spread of the points imaged by the imager. For example, the method of claim No. 105 of the scope of the patent application, and the method of claim 2, the scope of claim 2, and the method of claim 32.