TW201837528A - Imaging method for low contrast features - Google Patents

Abstract

A microscope system includes a light source, a spatial light modulator, a lens and a beam splitter aligned along an illumination axis, and a camera and objective aligned along an imaging axis. The beam splitter is also aligned along the imaging axis. The spatial light modulator is configured to spatially modulate light emitted by the light source to produce an arrangement of light and dark areas.

Description

 Imaging method for low contrast features  

The present invention relates to an imaging method for low contrast features.

Cross-reference to related applications

The present invention claims the benefit of U.S. Provisional Application Serial No. 62/435,671, filed on Dec.

For quality assurance purposes, it is desirable to place identification marks on transparent components (eg, formed of glass, sapphire, polymers such as polycarbonate, etc.) during the manufacturing process to track a single item and lot throughout the production process. Tracking the unit body throughout the process allows the manufacturer to identify specific production steps that introduce defects of unqualified quality and correct them. The challenge of applying an identification mark on or in a transparent component, such as a transparent window, is that after production, the end user of the product should not notice the identification mark (eg, the user may have purchased a phone or watch with such an identification mark) ). One way to achieve this is to make such identification marks quite small. Exemplary identification indicia can include a QR code (eg, 200 x 200 micron size, consisting of dots of two microns in size), a bar code (eg, consisting of parallel lines of adjacent or overlapping points), or the like, or any combination thereof. The points identifying the marks can be produced by laser interference of the glass material and can be made small and have such low contrast that human observers are at least less likely to notice them.

In some cases, it is customary to coat one surface of a transparent member with a light (e.g., white) coating. However, especially when one side of the transparent member has a white paint coating, the identification mark may become substantially invisible to the optical microscope. Embodiments discussed in more detail below provide methods and systems for establishing high contrast images of such identification marks.

Another embodiment of the invention may be characterized by a method of detecting indicia embedded in the area of a transparent component. The transparent member may have a first surface and a second surface opposite the first surface and a light colored coating formed on the second surface below the embedded indicia. The method can include projecting a pattern of bright and dark regions through the region of the transparent member and onto the coating and capturing the behavior of the embedded indicia image and the projected pattern.

Another embodiment of the invention may be characterized by a microscope system comprising a light source arranged along an illumination axis, a spatial light modulator, a lens and a beam splitter, and a camera and an objective lens arranged along the imaging axis. The beam splitters are also arranged along the imaging axis. The spatial light modulator is configured to spatially modulate light emitted by the light source to produce an arrangement of bright and dark regions.

100‧‧‧identification mark

100a‧‧ points

300‧‧‧Identification Mark Detection System

302‧‧‧ Objective lens

304‧‧‧beam splitter

306‧‧‧Mirror tube

308‧‧‧ camera

310‧‧‧First group of lenses

312‧‧ ‧ field of view

314‧‧‧ patterned markings

316‧‧‧Second lens

318‧‧‧ aperture diaphragm

320‧‧‧focus lens

322‧‧‧Light source

324‧‧‧ Transparent parts

324a‧‧‧ upper surface

324b‧‧‧ lower surface

1 and 2 illustrate identification marks embedded in a transparent member and at different locations relative to a projected field stop pattern, in accordance with one embodiment.

Figure 3 illustrates one embodiment of a system for detecting identification marks, such as the identification marks shown in Figures 1 and 2.

Figure 4 illustrates one embodiment of a reticle for projecting a field stop pattern.

Exemplary embodiments are described herein with reference to the drawings. The size, position, etc. of the components, features, elements, and the like, and any distances between them are not necessarily drawn to scale, but are exaggerated for clarity. In the figures, like numerals have been used to refer to similar elements. Therefore, the same or similar numerals may be described with reference to the other drawings, even if they are neither mentioned nor described in the corresponding drawings. Moreover, elements that are not represented by the component symbols may be described with reference to other drawings.

The terms used herein are for the purpose of describing particular example embodiments only and are not intended to be limiting. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning meaning meaning As used herein, the singular forms "", " It is to be understood that the phrase "comprising" and """ The entirety, steps, operations, elements, components, and/or combinations thereof are present or added. Ranges of values recited include the upper and lower limits of the range and any sub-ranges therebetween, unless otherwise indicated. Terms such as "first", "second", and the like, are used to distinguish one element from another. For example, one node may be referred to as a "first node," and another node may be referred to as a "second node," and vice versa.

The terms "about", "about" and the like mean that the quantity, size, form, parameters, and other quantities and characteristics are not, and are not necessarily, precise, and may be approximate and/or greater or Smaller to reflect tolerances, conversion factors, rounding off, measurement errors, etc., as well as other factors known to those skilled in the art. For ease of description, such as "under", "below", "below", "on", and "above" may be used herein. Spatial equivalents are used to describe the relationship of one element or feature to another element or feature, as shown. It should be appreciated that spatially relative terms are intended to include different orientations in addition to the orientation depicted in the figures. For example, elements in the "following" or "beneath" or "an" or "an" Thus, the exemplary term "under" can encompass the orientations above and below. The article may also be otherwise oriented (eg, rotated 90 degrees or in other directions), and the spatially relative description used herein may be interpreted accordingly.

According to one embodiment discussed herein, a low contrast identification mark embedded in a transparent member (eg, formed of a material such as glass, sapphire, or a polymer material such as polycarbonate) is passed through alternating bright and dark regions The patterned reticle is placed at the field stop of the optical microscope to be detected (see, for example, Figures 3 and 4). Within an optical microscope, the patterned reticle establishes a high contrast view of the embedded identification indicia in the transparent component, wherein the transparent component has a brightly coated underside. When the light passing through the field of view of the microscope uniformly illuminates the coated bottom side of the glass, the light diffuses in all directions and "wash-outs" the code. By placing the patterned reticle at or near the field stop and selectively illuminating objects having bright and dark regions, some of the light is reflected from the coated surface and illuminates the embedded identification mark (eg, Parts (eg, dots) provided by QR code, bar code, etc., but the background of the coated area below these points is still dark, resulting in contrast. In bright areas, the identification code is also visible because the surrounding areas are dark and these points are often not "flushed" because the light is only reflected back from below them, rather than being reflected back from a variety of angles. For example, as shown in FIG. 1, a dark line of a field stop pattern projected by an optical microscope incorporating a patterned reticle as described above is embedded in a transparent member (eg, a clear glass window). The underside of the identification mark is slightly out of focus, and the transparent member, such as a clear glazing, has a lower side coated with a white paint, which gives a contrast to the pattern. Referring to Figure 1, the identification mark 100 is composed of a plurality of points 100a. The identification mark 100 has a size of about 200 x 200 microns, while the point 100a has a maximum size of about 2 microns. As shown in FIG. 2, even at the corner of the field of view of the optical microscope, the identification mark 100 can be seen against the projected field of view pupil pattern.

3 is a view schematically illustrating an embodiment of an optical microscope (also referred to herein as a system for detecting an identification mark or an identification mark detection system) configured to project the above-described field stop pupil pattern. Referring to FIG. 3, the identification mark detection system 300 can include an objective lens 302 (eg, a bright field microscope objective), a beam splitter 304, a lens barrel 306 (eg, including a relay lens), a camera 308 (eg, a digital camera), first Group lens 310 (note: first set of lenses 310 may be comprised of a single lens or multiple lenses), field stop 312, patterned reticle (shown here at 314), second set of lenses 316 (note: The second set of lenses 316 may be comprised of a single lens or multiple lenses), aperture stop 318, focusing lens 320, and light source 322.

As exemplarily illustrated in FIG. 3, the first set of lenses 310, field stop 312, patterned reticle 314, second set of lenses 316, aperture stop 318, focus lens 320, and light source 322 may be illuminated The shafts (not shown) are arranged together to feature. Beam splitter 304 can reflect light transmitted along the illumination axis (i.e., from source 322) into objective lens 302 where it is focused onto transparent component 324/lens component 324. Objective lens 302, lens barrel 306, and camera 308 can be characterized as being aligned along an imaging axis (not shown). Light reflected from the transparent member 324 into the objective lens 302 can be transmitted to the camera 308 through the beam splitter 304 along the imaging axis. Therefore, the beam splitter 304 is arranged along the illumination axis and the imaging axis.

As with the above configuration, the focus lens 320 acts to collect and collimate the light emitted by the light source 322 (i.e., illumination light). The illumination light is ultimately transmitted from the focusing lens 320 through the patterned reticle 314. Thus, the identification mark detection system 300 is configured to project (eg, as discussed above) the field stop pattern through a transparent member 324 (eg, formed of clear glass, sapphire, or a polymeric material such as polycarbonate). . The transparent member 324 includes an upper surface 324a that is permeable (or at least substantially permeable) to light projected by the identification mark detection system 300 (eg, from the objective lens 302). The transparent member 324 also includes a lower surface 324b coated with a light colored coating such as a white paint. This coating is not shown in Figure 3. The field stop pattern passes through the upper surface 324a, passes through the interior of the transparent member 324, and is projected onto the coating applied to the lower surface 324b of the transparent member 324.

Despite the above structure, it should be understood that the identification mark detecting system 300 can be constructed differently. For example, one or both of field stop 312 and aperture stop 318 may be omitted from identification mark detection system 300. In another example, the second set of lenses 316 can be omitted from the identification mark detection system 300. In another example, for example, the first set of lenses 310 can be moved for insertion between the field stop 312 and the patterned reticle 314. In another example, although not shown in FIG. 3, the identification mark detection system 300 can optionally include a diffuser disposed on a side of the focus lens 320 opposite the light source 322 (eg, such that the focus lens is made 320 is between the light source 322 and the diffuser). In one embodiment, the diffuser can be provided as a full-image diffuser. The diffuser can be used to make the light transmitted by the focusing lens 320 slightly misaligned and slightly more uniform.

In one embodiment, although not shown, the identification mark detection system 300 can optionally include a focus adjustment mechanism operative to identify the focus of the identification mark detection system 300 from the embedded transparent component 324. Move above the marker to the bottom (or vice versa). In one embodiment, the focal length adjustment mechanism can be configured as a variable focus lens, a variable radius mirror, a mechanical platform, or the like, or any combination thereof. When provided with a variable focus lens or a variable radius mirror, the focus adjustment mechanism can be incorporated into the identification mark at any suitable or desired location (eg, between objective lens 302 and beam splitter 304) Detection system 300. When provided with a mechanical platform, the focal length adjustment mechanism is operable to support and move the objective lens 302 (eg, relative to the transparent member 324) to support and move the transparent member 324 (eg, relative to the objective lens 302), etc., or any combination thereof.

In one embodiment, the patterned reticle 314 is a fixed fixture within the identification mark detection system 300. However, in an alternate embodiment, the patterned reticle 314 can move within the identification mark detection system 300. In this alternative embodiment, the identification mark detection system 300 can include a motion platform (eg, a motorized motion platform) coupled to the patterned reticle 314 and configured to move the patterned reticle 314 (eg, to enable patterning) The bright and dark regions of the reticle 314 move in a direction transverse to the optical axis of the second set of lenses 316).

In view of the discussion provided above, the field stop pattern projected by the identification mark detection system 300 can be considered to be derived from the pattern of bright and dark areas of the patterned reticle 314. In another embodiment, the projected field stop pattern may be derived from an electrically addressable or optically addressable spatial light modulator (eg, a micro mirror array, a liquid crystal light valve, etc.), collectively referred to herein. "Addressable Space Light Modulator". In this case, the identification mark detection system 300 can include an addressable spatial light modulator in place of or in addition to the patterned reticle 314, an addressable spatial light modulator. In general, the addressable spatial light modulator is operable to create and change the arrangement of the bright and dark regions, which may ultimately form the field stop pattern projected by the identification mark detection system 300. The field stop pattern projected by the identification mark detection system 300 can be considered to be derived from a pattern of bright and dark areas of the patterned reticle 314 or a pattern produced by an addressable spatial light modulator. To the extent that it is derived, each of the patterned reticle 314 and the addressable spatial light modulator can be collectively referred to as a "spatial light modulator."

Although not shown, the identification mark detection system 300 can also include a computer (eg, a general purpose computer) coupled to the output of the camera 308 (ie, when the camera 308 is provided with a digital camera). In this case, camera 308 can generate image data corresponding to the image (eg, capture light that is reflected from transparent component 324 and transmitted to camera 308 through objective lens 302, beam splitter 304, and lens barrel 306) and the computer can The image data is configured (e.g., with appropriate image processing hardware and/or software) to detect the presence of an identification mark embedded within the transparent component 324. The computer can also be configured to generate and output detected data based on processing of the image data.

In one embodiment, the first set of lenses 310 are designed such that the chromatic aberration is emphasized such that the color of the human visible spectrum reflected from the transparent member 324 is spread over a range of expected locations of the embedded indicia within the transparent member 324. In this embodiment, the relay lens in the barrel 306 is designed to converge the scatter color of the human visible spectrum onto the sensor of the digital camera 308.

Although not shown, the identification tag detection system 300 can further include a controller communicatively coupled to the computer (eg, computer I/O port, USB port, etc.), communicatively coupled to the focus adjustment mechanism Inputs that are input, communicatively coupled to camera 308 (eg, where camera 308 is a digital camera), communicatively coupled to an input of a motorized motion platform (which in turn is coupled to patterned reticle 314), and/or addressable The input of the spatial light modulator, etc., or a combination thereof, and is configured to control the operation of any components coupled thereto.

For example, in one embodiment, the controller is configured to control the operation of the focus adjustment mechanism (e.g., the focus of the mobile identification mark detection system 300 as described above). The controller may also be configured to control the operation of the computer or camera 308 (ie, capture an image of light reflected from the transparent component 324) after the focus of the identification mark detection system 300 has moved. In one embodiment, the focus of the recognition mark detection system 300 can be repeatedly moved by the incremental distance and the image can be captured whenever the focus has moved. By alternately moving the focus and capturing the resulting image, the computer can process the image data to determine the focus that is embedded within the transparent component 324 via the embedded indicia.

In another example embodiment, the controller may be configured to control the operation of the motorized motion platform (which in turn is coupled to the patterned reticle 314) and/or the addressable spatial light modulator such that the offset is identified by The pattern of the bright and dark regions of the field stop pattern projected by the marker detection system 300. The controller may be further configured to control operation of the computer or camera 308 (ie, capture a map of light reflected from the transparent member 324 after the pattern of bright and dark regions of the projected field diaphragm pattern has been shifted) image). In one embodiment, the pattern of bright and dark regions of the projected field stop pattern that has been shifted may be repeatedly offset by the incremental distance and the image may be captured whenever the pattern has been shifted. In general, the incremental distance may be in the range of 0.1 μm (or about 0.1 μm) to 10 μm (or about 10 μm) (for example, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, 4 μm, 5 μm, 8 μm, 9 μm, etc.) Any value between the ranges). By alternately shifting the pattern and capturing the resulting image, the image of each region embedded in the marker can be captured with a background of different brightness levels. The image data corresponding to the captured image can thus facilitate the accuracy and reliability detection of the indicia embedded within the transparent component 324 at the computer. As described above, the process of capturing images at different levels of brightness may be performed after determining that the embedded indicia is present in the focus within the transparent component 324.

Typically, the controller includes one or more processors configured to control one or more operations of the focus adjustment mechanism to generate the control signals when the instructions are executed. The processor can be configured as a programmable processor that executes the instructions (eg, including one or more general purpose computer processing, a microprocessor, a digital signal processor, etc., or any combination thereof). The instructions executable by the processor may be software, firmware, etc. or include a programmable logic device (PLD), a field-programmable gate array (FPGA), a field programmable object. Field-programmable object array (FPOA), any suitable form of circuitry including digital, analog and mixed analog/digital circuits, application-specific integrated circuits (ASICs), etc., or any combination thereof, etc. . Execution of instructions can be performed on one processor, distributed among multiple processors, in parallel between processors within a device, or in parallel between multiple device networks, etc., or any combination thereof. In one embodiment, the controller includes a tangible medium such as computer memory that is accessible by a processor (eg, via one or more wired or wireless communication links). As used herein, "computer memory" includes magnetic media (eg, magnetic tape, hard disk drives, etc.), optical disks, volatile or non-volatile semiconductor memory (eg, RAM, ROM, NAND type flash memory). Body, NOR type flash memory, SONOS memory, etc.), etc., and can be accessed in situ, remotely (eg, via a network), or a combination thereof. In general, the instructions may be stored as computer software (eg, executable code, files, instructions, etc., library files, etc.), which may be readily fabricated by those skilled in the art from the description provided herein (eg, C, C++, Visual Basic, Java, Python, Tel, Perl, Scheme, Ruby, etc.). Computer software is typically stored in one or more data structures that are passed by computer memory.

The above is a description of the embodiments and examples of the invention and should not be construed as limiting. Although the embodiments and examples have been described with reference to the drawings, the embodiments and examples, and the disclosed embodiments and examples, as well as Many other modifications are possible in other embodiments. 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, a person skilled in the art will understand that the subject matter of any sentence, paragraph, example or embodiment may be combined with the subject matter of some or all of the other sentences, paragraphs, examples or embodiments, unless such combinations are mutually exclusive. The scope of the invention is therefore intended to be defined by the appended claims

Claims (6)

 A method of detecting a mark embedded in an area of a transparent member, the transparent member having a first surface and a second surface opposite the first surface and the second formed under the indicia being embedded a light colored coating on the surface, the method comprising: projecting a pattern of bright and dark regions through the region of the transparent member and onto the coating; and capturing an image of the indicia embedded And the pattern being projected.    A microscope system comprising: a light source arranged along an illumination axis, a spatial light modulator, a lens and a beam splitter; and a camera and an objective lens arranged along an imaging axis, wherein the beam splitter is also arranged along the imaging axis Wherein the spatial light modulator is configured to spatially modulate light emitted by the light source to produce an arrangement of bright and dark regions.    The microscope system of claim 2, wherein the spatial light modulator comprises a patterned reticle.    The microscope system of claim 3, further comprising a motorized platform coupled to the patterned reticle, wherein the motorized platform is configured to move the patterning in a direction transverse to the illumination axis Marking line.    The microscope system of claim 2, wherein the spatial light modulator comprises an addressable spatial light modulator.    The microscope system of claim 2, further comprising a focal length adjustment mechanism configured to adjust a position of a focus of the microscope system.