Multi-wavelength optical sensor

Abstract

A multi-wavelength optical sensor includes an illuminator (301, 501, 1001). The illuminator includes an illuminator housing, one or more light emitting diodes (LEDs) (510, 1010) having different wavelengths disposed in the illuminator housing, and a light bar (509, 1000) disposed in the illuminator housing, the light bar including a light guide (505, 709, 1005) and a diffuser (518, 712, 1018) having a thickness and a width corresponding to a shape of a bottom portion of the light guide, wherein light emitted by the one or more LEDs is reflected within the light guide and the light is scattered by the diffuser through the light guide for transmission. The multi-wavelength optical sensor also includes a photodetector (303, 503) disposed opposite the illuminator. The photodetector includes a photodetector housing, an array of photodiodes (507) disposed within the photodetector housing, and an array of apertures (529) having a plurality of vertical walls for controlling scattered light transmitted by the illuminator and reducing stray light effects.

Description

Technical Field

[0001] This disclosure generally relates to optical object detection systems. More specifically, this disclosure relates to a multi-wavelength optical sensor. Background Technology

[0002] Devices and machines, such as those used for automating the handling of banknotes and other special securities, typically include optical sensors to provide measurements of the transparency of the object being processed. Sensors or sensor arrays used in devices for automating the handling of items such as banknotes, securities, documents, and other items generally collect information about the optical properties of the object being processed—particularly optical transmittance at various wavelengths of light. However, existing optical sensors suffer from various problems, such as undesirable stray light effects that reduce the accuracy of optical sensors. Summary of the Invention

[0003] This disclosure relates to a multi-wavelength optical sensor.

[0004] In one aspect of this disclosure, a multi-wavelength optical sensor includes an illuminator for placement in an item detection area. The illuminator includes an illuminator housing, one or more light-emitting diodes (LEDs) with different wavelengths disposed within the illuminator housing, and a light strip disposed within the illuminator housing. The light strip includes a light guide and a diffuser, the diffuser having a thickness and a width corresponding to the shape of the bottom portion of the light guide. Light emitted by the one or more LEDs is reflected within the light guide and scattered by the diffuser through the light guide for transmission to the outside of the illuminator.

[0005] In some embodiments, the multi-wavelength optical sensor further includes a photodetector for placement opposite the illuminator in the object detection area. The photodetector includes a photodetector housing, a photodiode array disposed within the photodetector housing, and an aperture array having multiple vertical walls for controlling scattered light transmitted by the illuminator and reducing stray light effects.

[0006] In another aspect of this disclosure, a light stripe for an optical device includes a light stripe having an end having a shape for deflecting light into a central portion of the light stripe. The light stripe also includes a diffuser having a thickness and a width corresponding to the shape of the bottom portion of a light guide. Light reflected within the light guide is scattered by the diffuser and passes through the light guide for transmission. The light stripe provides a stable illumination indication distribution.

[0007] In another aspect of this disclosure, a method includes: detecting an article in an article detection area of ​​a device by a multi-wavelength optical sensor, wherein the multi-wavelength optical sensor includes an illuminator disposed in the article detection area. The illuminator includes an illuminator housing, one or more light-emitting diodes (LEDs) having different wavelengths disposed within the illuminator housing, and a light strip disposed within the illuminator housing, the light strip including a light guide and a diffuser, the diffuser having a thickness and a width corresponding to the shape of the bottom portion of the light guide. The multi-wavelength optical sensor also includes a photodetector disposed opposite the illuminator in the article detection area. The photodetector includes a photodetector housing, a photodiode array disposed within the photodetector housing, and an aperture array having a plurality of vertical walls. Detecting an article includes: emitting light by the one or more LEDs; reflecting the emitted light within the light strip and scattering the light by the diffuser to allow it to pass through the light strip for transmission to the outside of the illuminator; receiving the scattered light transmitted by the illuminator by the photodetector; and controlling the scattered light and reducing stray light effects using the plurality of vertical walls of the aperture array.

[0008] Before proceeding with the specific implementation described below, it may be advantageous to define certain words and phrases used throughout this patent document. The term “coupled” and its derivatives refer to any direct or indirect communication between two or more elements, regardless of whether these elements are physically in contact with each other. The terms “transmit,” “receive,” and “communicate,” and their derivatives encompass both direct and indirect communication. The terms “comprising” and “including,” and their derivatives mean non-limiting inclusion. The term “or” is inclusive, meaning “and / or.” The phrase “associated with,” and its derivatives mean including, being included, interconnected with, containing, being contained, connected to or connected to, coupled to or coupled with, able to communicate with, cooperate with, interleave, juxtapose, adjacent to, combined with or combined with, having, possessing the properties of, having a relationship with, etc. The term “controller” means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, either local or remote.

[0009] Furthermore, the various functions described below can be implemented or supported by one or more computer programs, each computer program being formed by computer-readable program code and embodied in a computer-readable medium. The terms "application program" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or portions thereof suitable for implementation in appropriate computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium accessible by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, optical disc (CD), digital video disc (DVD), or any other type of storage. "Non-transitory" computer-readable media does not include wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transitory computer-readable media includes media that can permanently store data as well as media that can store data and subsequently overwrite it, such as rewritable optical discs or erasable memory devices.

[0010] As used herein, terms and phrases such as “having,” “may have,” “comprising,” or “may include” indicate the presence of a feature (such as a number, function, operation, or component (such as a part)) and do not exclude the presence of other features. Additionally, as used herein, the phrases “A or B,” “at least one of A and / or B,” or “one or more of A and / or B” can include all possible combinations of A and B. For example, “A or B,” “at least one of A and B,” and “at least one of A or B” can indicate all of the following: (1) including at least one A, (2) including at least one B, or (3) including at least one A and at least one B. Furthermore, as used herein, the terms “first” and “second” can modify various components regardless of importance and do not limit the components. These terms are used only to distinguish one component from another. For example, a first user equipment and a second user equipment can refer to user equipments that are different from each other, regardless of the order or importance of the equipment. Without departing from the scope of this disclosure, a first component can be referred to as a second component, and vice versa.

[0011] It should be understood that when an element (such as a first element) is referred to as being "coupled to" or "connected to" another element (such as a second element) (operably or communicatively), it may be directly coupled or connected to that other element or via a third element. Conversely, it should be understood that when an element (such as a first element) is referred to as being "directly coupled to" or "directly connected to" another element (such as a second element), there is no other element (such as a third element) intervening between that element and that other element.

[0012] As used herein, the phrase “configured (or set) to” may be used interchangeably with the phrases “suitable for,” “capable of,” “designed to,” “suitable for,” “made as,” or “capable of.” The phrase “configured (or set) to” does not necessarily mean “specifically designed in hardware.” Rather, the phrase “configured to” may mean that a device can perform operations in conjunction with another device or component. For example, the phrase “processor configured (or set) to perform A, B, and C” may mean a general-purpose processor (such as a CPU or application processor) that can perform operations by executing one or more software programs stored in a memory device, or a specialized processor (such as an embedded processor) for performing operations.

[0013] The terms and phrases used herein are provided only to describe some embodiments of this disclosure and do not limit the scope of other embodiments of this disclosure. It should be understood that the singular forms “a,” “an,” and “the / described” include plural references unless the context clearly indicates otherwise. All terms and phrases used herein, including technical and scientific terms and phrases, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this disclosure pertain. It should also be understood that terms and phrases (such as those defined in common dictionaries) should be interpreted as having the meaning consistent with their meaning in the context of the relevant field and should not be interpreted in an idealized or overly formal sense unless expressly defined herein. In some cases, terms and phrases defined herein may be interpreted as excluding embodiments of this disclosure.

[0014] This patent document provides definitions for certain other words and phrases throughout. Those skilled in the art will understand that, in many (if not most) cases, such definitions apply to the prior and future use of such defined words and phrases. Attached Figure Description

[0015] To gain a more complete understanding of this disclosure, reference is now made to the following description in conjunction with the accompanying drawings, wherein: Figure 1 An example banknote processing system based on this disclosure is illustrated; Figure 2 A perspective view of a document processing system based on this disclosure is illustrated; Figure 3A and Figure 3B This illustrates typical sensor operation, showing the light trails during the presence and absence of an object in the transport path; Figure 4A and Figure 4B An example illustrating the dependence of the output signal on the orientation of an object in the transport path is provided. Figures 5A-5C Example multi-wavelength optical sensors according to this disclosure are illustrated; Figure 6A Examples are given based on this disclosure. Figure 5A and Figure 5B Exploded view of the illuminator of a multi-wavelength optical sensor; Figures 6B-6D Examples are given based on this disclosure. Figure 6A Views of the light stripe of the illuminator; Figure 7 Examples illustrating how light can be reflected through a light stripe; Figure 8A Examples are given based on this disclosure. Figure 5A and Figure 5B Exploded view of the photodetector of a multi-wavelength optical sensor; Figure 8B Examples are given based on this disclosure. Figure 8A A view of the aperture array of the photodetector; Figure 8C A cross-sectional view of a single sensor in a sensor array according to this disclosure is illustrated; Figure 8D Examples are given based on this disclosure. Figure 8C A single sensor component; Figure 8E Examples are given based on this disclosure. Figure 8A A cross-sectional view of the photodetector; Figure 9 An example of the stray light effect is illustrated; Figures 10A-10D Various views of example light bars according to this disclosure are illustrated; Figure 10E Examples of the provisions of this disclosure include Figures 10A-10D An example illuminator with a light stripe; Figure 11An embodiment of a method for detecting an article using a multi-wavelength optical sensor according to the present disclosure is illustrated; and Figure 12 Example electronic systems based on this disclosure are illustrated. Detailed Implementation

[0016] The following discussion Figures 1 to 12 The various embodiments used in this patent document to describe the principles of this disclosure are merely illustrative and should not be construed as limiting the scope of this disclosure in any way. Those skilled in the art will understand that the principles of this disclosure can be implemented in any suitably arranged device or system.

[0017] As used throughout this specification, the terms currency denomination, face value of currency, negotiable instrument, monetary instrument, bill, banknote, note, cheque, bank cheque, paper money, paper currency, polymer banknote, polymer banknote, polymer currency, bill of exchange, coupon, voucher, and cash are used interchangeably to refer to a negotiable instrument or any other written instrument proving the right to pay a monetary debt, usually issued by a central banking institution.

[0018] As described above, devices and machines, such as those used for automatically handling banknotes and other special securities, typically include optical sensors to provide measurements of the transparency of the detected object. Sensors or sensor arrays used in devices for automatically handling items such as banknotes, securities, documents, and other articles typically collect information about the optical properties of the object being handled—particularly optical transmittance at various wavelengths of light. However, existing optical sensors suffer from various problems, such as undesirable stray light effects that reduce the accuracy of the optical sensors.

[0019] This disclosure provides an implementation of a multi-wavelength optical sensor that provides self-calibration of the ratio between object transparency and sensor output signal, suppression of differences in sensor output signal under different object insertion orientations (e.g., face up or face down), and reduction of the influence of stray light passing through areas of the optical system that are not overlapped by the detected object.

[0020] The optical sensors and associated systems described in this disclosure can be implemented in a wide variety of articles handling machines or devices, such as ticket vending machines, check scanners, ATMs, point-of-sale machines, banknote handling or recycling machines, document scanners, authentication devices, etc. The optical sensors and associated systems of this disclosure can be integrated into such machines or devices to provide improved detection of articles that the machine or device is designed to handle, thereby enabling authentication / verification of such articles.

[0021] For example, Figure 1 An example banknote processing system 100 according to this disclosure is illustrated. The multi-wavelength optical sensor and associated article detection system of this disclosure can be implemented in the banknote processing system 100. However, it should be understood that the banknote processing system 100 is merely an embodiment, and as mentioned above, the multi-wavelength optical sensor and associated article detection system of this disclosure can be implemented in a wide variety of systems, machines, or devices.

[0022] The banknote processing system 100 may include a frame, a chassis, a receiving head, a banknote conveying mechanism, a banknote conveying path, one or more sensors for verifying the authenticity of inserted banknotes, a banknote storage unit, and / or a banknote receiving-sorting module. Figure 1 The banknote processing system 100 can also be used in or incorporated into other systems (such as unattended payment systems, point-of-sale systems or other currency processing devices).

[0023] In various embodiments, the banknote handling system 100 is configured to verify the authenticity of inserted banknotes. The banknote handling system 100 typically has a receiving head, a banknote delivery system, and a removable banknote storage unit. Various sensors, as further described in this disclosure, are typically used to authenticate the inserted banknote in the banknote receiving module. Once the banknote is deemed genuine and acceptable, the banknote delivery system further delivers the banknote to the banknote receiver, into the banknote storage unit, which may be removable. If the banknote is rejected, it can be removed from the banknote handling system 100. When the optical sensors and systems of this disclosure are implemented in other types of machines or devices, similar processes can be used to authenticate / verify items, such as rejecting or accepting such items based on the output provided by the optical sensors and / or sensor systems.

[0024] although Figure 1 An embodiment of the banknote processing system 100 is illustrated, but it is possible to... Figure 1 Make various changes. Figure 1 The various components of a banknote processing system can be rearranged, omitted, combined, or further subdivided according to specific needs, and additional components can be added. For example, banknote processing system 100 may include any number of temporary storage modules, storage modules, or recycling modules. Banknote processing system 100 can be used in automatic ticket vending machines, automatic payment systems, unattended payment systems, point-of-sale systems, customer-assisted payment systems, ATMs, vending machines and other self-service terminals, electronic game machines, or other currency processing devices / systems. Typically, banknote processing systems can have multiple configurations, and Figure 1 This disclosure is not intended to be limited to any particular configuration.

[0025] As another embodiment, Figure 2 A perspective view of a document processing system 200 according to this disclosure is shown. For example... Figure 2 As shown, the file processing system 200 includes a file processing device 201 and an output section 210a. The output section 210a of the file processing system 200 includes a base module 202. That is, the file processing system 200 includes a file processing device 201 coupled to the output section 210a, wherein the output section 210a includes one or more modules (e.g., the base module 202). The file processing system 200 may include one or more output containers or pockets.

[0026] The multi-wavelength optical sensor and associated article detection system of this disclosure can be implemented in document processing system 200. However, it should be understood that document processing system 200 is merely an embodiment, and as described above, the multi-wavelength optical sensor and associated article detection system of this disclosure can be implemented in a wide variety of systems, machines, or devices.

[0027] although Figure 2 An embodiment of the document processing system 200 is illustrated, but it is possible to... Figure 2 Make various changes. Figure 2 The various components of a file processing system can be rearranged, omitted, combined, or further subdivided according to specific needs, and additional components can be added. For example, file processing system 200 may include any number of temporary storage modules, storage modules, or recycling modules. Typically, file processing systems can have multiple configurations, and Figure 2 This disclosure is not intended to be limited to any particular configuration.

[0028] Figure 3A and Figure 3B An embodiment of general sensor operation 300 is illustrated. The sensor includes an illuminator 301 that illuminates the surface of an article 302 (illustrated using exemplary light rays 1-7) from one side of an article transport path through which the article 302 travels during its processing. The sensor also includes a photodetector 303 located on the other side of the article transport path that records the light passing through the article transport path.

[0029] Transparency determines which portion of the incident light passes through to the opposite side of item 302. For example... Figure 3A As shown, when there is no object 302 between the illuminator 301 and the photodetector 303, the photodetector 303 can collect a portion of the illumination light. Figure 3BAs shown, when the object 302 passes between the illuminator 301 and the photodetector 303, the photodetector 303 can collect a portion of the illumination light transmitted through the object 302. Each portion of the light rays 1-7 is converted into a proportional electrical signal by the photodetector 303.

[0030] However, problems may arise because the relationship between these two signals cannot be used directly. The relationship can be used if the relative portions of the light incident on the photodetector 303 are the same, but... Figure 3A and Figure 3B As shown, this is not the case. On the contrary, Figure 3A and Figure 3B The light collected by the photodiode of the photodetector 303 originates from different initial light emitted by the illuminator 301. Because the object 302 causes the light rays 1-7 to be redirected or bent, different light rays are incident on the photodetector 302 when the object is between the illuminator 301 and the photodetector 302.

[0031] Therefore, a practical way to overcome this situation is through the calibration of optical sensors. For example, by applying an object simulating its transparency, it is possible to... Figure 3A and Figure 3B The two scenarios shown obtain calibration values ​​for the relationship between transparency and the ratio of light collected by photodetector 303. In other words, calibration can be performed between transparency and the sensor's output signal level, both when an object is present and when no object is present in the item transport path.

[0032] The calibration value will be correct as long as the correlation between the light emitted by illuminator 301 in various directions remains the same. This correlation is typically described in terms of the concept of the indication distribution produced by illuminator 301. Due to manufacturing variations, there is variability in the indication distribution between illuminators, thus requiring calibration for each illuminator during or after manufacturing. It is desirable to reduce or eliminate these manufacturing variations so that the indication distribution of each illuminator is reproducible between illuminators, thereby allowing calibration for a specific illuminator design to be performed once during sensor design, without needing to repeat the calibration for each illuminator with the same design as part of the manufacturing process.

[0033] As described herein, the optical sensor of this disclosure addresses the aforementioned problem by providing an arrangement of illuminators that provides a reproducible illumination indication distribution.

[0034] Another problem with optical sensors is that the illumination and the amount of light collected by the photodetector 303 may depend on the orientation of the inserted object or item, such as whether the object or item is inserted face up or face down. Figure 4A and Figure 4B This phenomenon is illustrated. The problem arises when the surface of object 302 facing the illuminator 301 is not only directly illuminated by the main light 406 (e.g., ... Figure 4A As shown), and is also illuminated by additional light 407 falling on the surface (as shown). Figure 4B (As shown).

[0035] For example, such as Figure 4B As shown, if the surface of article 302 facing illuminator 301 is a bright surface 404, a portion of the main light is reflected in the direction of illuminator 301. The illuminator consists of parts that are either extremely transparent or extremely white. This is necessary for achieving high efficiency in the illuminator, but it also creates conditions where supplementary light 407 is redirected back to the illuminated surface, thus providing undesirable supplementary illumination. As a result, photodetector 303 collects the supplementary light 408. Figure 4A As shown, if the surface of article 302 facing illuminator 301 is dark surface 405, then Figure 4B The phenomenon shown does not occur. Therefore, the signal from an object with different images on different sides becomes dependent on which side faces the illuminator 301, such as an item with unprinted parts and printed parts.

[0036] As described herein, the optical sensor of this disclosure solves the above problems by providing an optical sensor arrangement that enables the sensor signal to be independent regardless of which side of the object faces the illuminator.

[0037] Another problem is that in practical designs, all individual sensors operate simultaneously, and the sensor array consists of these individual sensors. That is, some sensors in the array tend to face the object, but some sensors have direct access to the illuminator because the object is typically smaller than the width of the conveyor path, and therefore the object does not block light from the illuminator in some sections of the conveyor path. This stray light flowing through the non-overlapping areas of the conveyor path is very strong, causing it to be scattered by the components of the photodetector unit, and thus illuminating the object surface facing the photodetector, which in turn leads to an external signal to the photodetector.

[0038] As described herein, the optical sensor of this disclosure addresses the aforementioned problems by capturing stray light to prevent it from propagating along the array lines and avoiding stray light from illuminating the surface of the object.

[0039] Figures 5A-5C An example multi-wavelength optical sensor 500 according to this disclosure is illustrated. For example... Figures 5A-5CAs shown, for example, the multi-wavelength optical sensor 500 includes two units: an illuminator 501 for placement on one side of the transport path (such as the bill path in a currency processing device); and a photodetector 503 for placement on the opposite side of the transport path from the illuminator 501, such as... Figure 3A and Figure 3B As shown in the image. Figure 5B and Figure 5C As shown, the photodetector 503 may include a photodiode array 507.

[0040] Figure 6A An exploded view of a luminaire 501 according to this disclosure is illustrated, and Figures 6B-6D A view of the light strip 509 of an illuminator 501 according to this disclosure is shown.

[0041] like Figures 6A-6D As shown, the illuminator 501 includes a light strip 509 into which feed light of different wavelengths from a light-emitting diode (LED) 510 is injected for further measurement of the object's transparency in multiple regions of the spectrum. The light strip 509 includes a transparent light guide 505 and a diffuser 518.

[0042] like Figure 7 As shown, Figure 7 An embodiment 700 illustrates how light 711 can be reflected through a light guide 709, emitted by an LED 710, filling the volume of the light guide 709 due to repeated total internal reflection. A diffuser 712 is applied to the side of the light guide 709 opposite the illuminated object 702 to scatter light 711 as ray 750 in the direction of the illuminated object 702. In previous designs, a layer of white paint was used as the diffuser. This results in low reproducibility of the illumination indication distribution due to the poor reproducibility of the parameters scattered by the paint diffuser. They are affected by the presence of total internal reflection at the transition between the layers passing through the light guide 709 and the diffuser 712, due to the complex structure of the layers and / or insufficient paint coverage, causing variations in the degree of scattering to depend, among other factors, on the thickness of the paint layer and also on the tendency of the paint to diffuse.

[0043] Refer again Figures 6A-6DThe illuminator 501 incorporates an improved design to avoid the aforementioned problems. Illuminator 501 provides repeatability of the indication distribution between illuminators during manufacturing, so that calibration is performed once, such as during sensor design, and does not require calibration for each illuminator during or after manufacturing. Sensor 500 includes a housing 513 covered by a protective transparent cover 514, within which a light strip 509 is disposed. The transparent cover 514 may be made of plastic, glass, or other materials. The light strip 509 has a light guide 505 with a beveled end 516 that guides feed light emitted by LED 510 into the light guide 505. In various embodiments, the light guide 505 is transparent and may be made of plastic or other materials. The beveled end 516 of the light guide 505 is covered by a light shield 517 that prevents light emitted by the LED from leaking from the light guide 505. In various embodiments, the light shield 517 is white and may be made of plastic. The light strip 509 also includes a diffuser 518 located at the bottom portion of the light guide 505. The diffuser 518 may be an opaque, blocky material, such as plastic. The LED 510 is placed on a printed circuit board (PCB) 519.

[0044] like Figures 6B-6D As shown, illuminator 501 improves upon the repeatability issues described in this disclosure regarding the indication distribution of the illuminator for the following reasons. The diffuser 518 of light strip 509 has a thickness and a width corresponding to the shape of the bottom portion of light guide 505. This thickness can be the thickness of a bulk material, rather than the thickness of a thin coating layer as in previous designs. Such a thin coating layer can be applied inconsistently, resulting in variations in the thickness of the applied coating. The thickness and width of the diffuser 518 of light strip 509 provide for smaller relative variations in its dimensions during manufacturing. In some embodiments, the bottom portion of light guide 505 has a constant width over its entire length. In some embodiments, the bottom portion of light guide 505 varies in width over its length. As explained in this disclosure, previous designs used white paint as the diffuser. White paint is typically applied as a single layer, and manufacturing variations resulted in less repeatability of the performance of previous diffusers between illuminators. While multiple layers of paint can be applied, there are practical manufacturing considerations regarding the ability to apply a sufficient number of paint layers to potentially reduce variations in the indication distribution. The diffuser 518 of this disclosure has a thickness of a bulk material (such as plastic) such that the diffuser 518 is thick enough that the diffuser 518 is maximized at any wavelength of the LED 710 and does not change with further increases in thickness. If the diffuser were as thin as previous designs (such as those using one or more layers of white paint), light could be transmitted through the diffuser and leak out from the bottom.

[0045] The increased thickness of the bulk material in diffuser 518 provides stability relative to previous designs (such as coated strips) because coating the surface of a light guide with one or more layers of paint is more difficult to control than molding a thick plastic part. Therefore, the light strip 509 of this disclosure is calibrated by the design itself, and individual light strip calibrations to account for manufacturing variations are not required. In various embodiments, the light guide 505 and diffuser 518 can be manufactured using injection molding technology to provide greater stability and consistency in the manufacturing of the light guide 505 and diffuser 518. In various embodiments, the same base plastic material can be used for both the light guide 505 and diffuser 518, making the transition layer 520 between the light guide 505 and diffuser 518 optically inactive after molding, thus providing no light reflection. For diffuser 518, the substrate is doped, making diffuser 518 appear opaque. In various embodiments, diffuser 518 is doped with a white pigment, such as titanium dioxide, zinc oxide, or calcium carbonate. In various embodiments, diffuser 518 can be injection molded during manufacturing before the light guide 505. In other embodiments, the light guide 505 can be injection molded during manufacturing before the diffuser 518.

[0046] like Figure 6D As shown, the width of the diffuser 518 can correspond to the shape of the bottom portion of the light guide 505, and the combination of the two constitutes the transition layer 520. As light from the LED is transmitted, it is directed upwards, reflected from the angled end 516 of the light guide 505, and then scattered by the diffuser 518 as scattered light 550. The indicative distribution of the scattered light is also influenced by the internal angled shape of the light guide 505. However, the bulk material thickness of the diffuser 518 increases the scattering rate and makes the scattering of light very stable, thus avoiding the inefficiency and unpredictability of scattered light at different wavelengths in previous illuminators.

[0047] Figure 8A An exploded view of a photodetector 503 according to this disclosure is shown. Figure 8B A view illustrating the aperture array of the photodetector 503 according to this disclosure is shown. Figure 8C A cross-sectional view 801 of a single sensor in a sensor array according to this disclosure is illustrated. Figure 8D Examples are given based on this disclosure. Figure 8C A single sensor component, and Figure 8E A cross-sectional view 802 of a photodetector 503 according to the present disclosure is shown.

[0048] In various embodiments, the photodetector 303 comprises a one-dimensional detector (i.e., a photodiode array). For example, Figure 8C and Figure 8DThe arrangement and function of individual sensors as part of an array are shown. Each sensor in the array includes a photodiode 521. A portion of the surface of an illuminated object 502 is projected by a lens 522 onto a sensitive region 523 of the photodiode 521. To provide the desired quality of the optical system, an aperture 524 is disposed between the lens 522 and the photodiode 521. The aperture 524 includes a central cutout portion corresponding to the lens 522, which helps control the light entering the photodiode 521, such as by narrowing the beam as it reaches the photodiode 521. Each photodiode 521 collects light from a corresponding portion of the detection path or region, with each subsequent sensor in the array collecting light from a different portion of the detection region (and, when present, the detectable object / item).

[0049] like Figures 8A-8E As shown, the components of the photodetector 503 are mounted on a PCB 525, which is placed within a housing 527. The housing 527 is covered by a protective transparent window 526, which is flush with the inner surface of the detection path or area. The transparent protective window 526 can be made of plastic, glass, or other materials. Figure 6A and Figure 8A As shown, each of PCBs 519 and 525 includes a flexible cable connector for connecting each of the illuminator 501 and the photodetector 503 to a device such as device 100 or 200. Figure 8A and Figure 8B As shown, the photodetector 503 includes a lens array 528 and an aperture array 529. The photodetector 503 also includes a light shield 530, which serves as the entrance to the photodetector 503. Figure 8A As shown, the light shield 530 has a cutout corresponding to the light diffuser 531. In various embodiments, the light shield 530 may be made of plastic, and in various embodiments may be black. In various embodiments, the light diffuser 531 may be made of plastic, and in various embodiments may be white. The light shield 530, the light diffuser 531, and the aperture array 529 help avoid the problems described in this disclosure by enabling the signal provided by the photodetector 503 to be independent of the side of the article or object facing the illuminator, and by capturing stray light to prevent it from propagating along the array lines and preventing stray light from illuminating the surface of the article.

[0050] Specifically, the light diffuser 531 provides signal independence based on the object's insertion orientation. In particular, the signal equalization of this disclosure is based on the fact that, through the equal light redirection capabilities of both the illuminator 501 and the photodetector 503, the signals under different orientations will also be equal. Since the initial problem stems from the high redirection capability of the illuminator, the white diffuser 531 effectively redirects a portion of the transmitted light back to the object / item surface for collection by the photodiode again. The desired redirection rate can be determined by the shape and position of the diffuser 531.

[0051] like Figure 8E As shown, the aperture array 529 is similar to the aperture 524, but the aperture array 529 includes a set of lens covers that prevent stray light from propagating along the photodiode array. For example, as Figure 9 As shown, Figure 9 An example of stray light effect 900 is illustrated where, if the photodetector does not include the aperture array 529, the light 950 emitted from the light strip 509 of the illuminator 501 can bypass the detected item 502 near its edge and illuminate the lens array 528. This results in additional illumination of the surface area 932 of the item 502 near its edge and facing the photodetector due to the reflection of the light by the reflective lens array 528.

[0052] Refer again Figure 8E Due to the vertical walls of the lens cover of the aperture array 529, excess illumination is suppressed. For example... Figure 8E As shown, the light 850 emitted from the light strip 509 of the illuminator 501 is controlled by the vertical wall of the aperture array 529 to prevent the light 850 from bypassing the detected item 502 near its edge, and also to guide the light 850 through the aperture array 529 and toward the appropriate lens and photodiode of the photodetector 503. Therefore, the photodetector 503 provides improved detection of items in the detection area and improved signal accuracy.

[0053] although Figures 5A-5C , Figures 6A-6D and Figures 8A-8E An example portion of a multi-wavelength optical sensor 500 is illustrated, but more details can be found on other examples. Figures 5A-5C , Figures 6A-6D and Figures 8A-8E Make various changes. For example, Figures 5A-5C , Figures 6A-6D and Figures 8A-8E The various components of the illuminator 501 and / or photodetector 503 shown can be rearranged, omitted, combined, or further subdivided according to specific needs, and additional components can be added. Generally speaking, Figures 5A-5C , Figures 6A-6D and Figures 8A-8E This disclosure is not intended to be limited to any particular configuration.

[0054] For example, the light strip of the illuminator can be configured in various ways. As a specific embodiment, Figures 10A-10E Various views of an example light bar 1000 according to this disclosure are illustrated. Figure 10A An example of a stereoscopic view of the light bar 1000 is shown. Figure 10B An exploded view of the light strip 1000 positioned above PCB 1019 is shown. Figure 10C This example shows a top view of the light strip 1000 positioned above PCB 1019. Figure 10D A side view of the light strip 1000 positioned above PCB 1019 is shown, and Figure 10E An example is shown: an illuminator 1001 incorporated into the light strip 1000.

[0055] The light guide 1005 of the light strip 1000 does not use a slanted end (such as the slanted end 516 of the light guide 505), but instead includes an end 1016, each end 1016 having a leg 1002 extending laterally from the end 1016 and located on both sides of the body of the light guide 1005 and the diffuser 1018, such as Figures 10A-10D As shown. Leg 1002 allows the LED 1010 of the illuminator to be located on PCB 1019, such that the LED 1010 is positioned on each side of the light guide 1005 and below the leg 1002, resulting in an overall reduction in the length of the sensor compared to other configurations such as illuminator 501 (which includes a light strip 509 with a slanted end 516).

[0056] This reduction in length allows sensors to be made shorter, enabling them to be installed in machines that may have limited internal space. For example... Figure 10E As shown, it should be understood that the light strip 1000 can be used in a luminaire having features similar to those of the luminaire 501 of this disclosure. For example, Figure 10E The illuminator 1001 shown may include various other features described with respect to illuminator 501, but may have a reduced length compared to the length of illuminator 501. This reduced length of the illuminator may also allow the photodetector corresponding to the illuminator (such as photodetector 503) to also have a reduced length matching the length of the illuminator.

[0057] Figure 11An embodiment of a method 1100 for detecting an article using a multi-wavelength optical sensor according to the present disclosure is illustrated. At step 1102, a multi-wavelength optical sensor (i.e., the multi-wavelength optical sensor 500 of the present disclosure, which includes an illuminator (e.g., illuminator 501) and a photodetector (e.g., photodetector 503)) is disposed in an article detection area of ​​the device, such as an article detection area of ​​device 100 or 200. At step 1104, light is emitted by one or more LEDs (e.g., LED 510) disposed in the illuminator housing of the illuminator. At step 1106, the emitted light is reflected within a light guide (e.g., light guide 505 of light strip 509) disposed in the illuminator housing, and the light reflected within the light guide is scattered using a diffuser (e.g., diffuser 518 of light strip 509) for transmission to the outside of the illuminator.

[0058] At step 1108, a photodetector receives the scattered light transmitted from the illuminator, wherein the photodetector includes a photodetector housing and a photodiode array. At step 1110, multiple vertical walls of an aperture array (such as aperture array 529) are used to control the scattered light received by the photodetector to further reduce light scattering and guide the light to the photodiode array.

[0059] At step 1112, a processor or other processing device, such as a device in which a multi-wavelength optical sensor is mounted, determines whether an article is detected. If no article is detected, method 1100 returns to step 1104. If an article is detected, the process proceeds to step 1114. At step 1114, the processor or other processing device performs imaging, detection, and / or authentication operations, in which the article may be imaged based on the detected optical characteristics, the detection status may be stored or otherwise transmitted or provided, and / or authentication may be performed based on the measured optical characteristics of the article, which may be used to determine whether the article is authentic. In such authentication operations, a result may be output and / or other device functions may be triggered, such as further receiving the article into the device (e.g., receiving it into a storage or temporary location), or rejecting the article and removing it from the device. Method 1100 ends at block 1116.

[0060] although Figure 11 An embodiment of a method 1100 for detecting articles using a multi-wavelength optical sensor is illustrated, but it is possible to modify... Figure 11 Various changes were made. For example, although it is shown as a series of steps, Figure 11 The various steps in the process can overlap, occur in parallel, occur in different orders, or occur any number of times (including zero times).

[0061] Figure 12Example electronic system 1200 is illustrated with various embodiments according to this disclosure. System 1200 may be an article handling machine or device (such as...) Figure 1 100 banknote processing systems Figure 2 The system 1200 is part of a file processing system 200 or any other system, machine, or apparatus incorporating embodiments of a multi-wavelength optical sensor. System 1200 includes a controller (e.g., a processor / central processing unit (“CPU”)) 1202, a memory unit 1204, and input / output (“I / O”) devices 1206. System 1200 also includes at least one network interface 1208 or a network interface controller (NIC).

[0062] System 1200 also includes one or more sensors 1210 for capturing and / or measuring data. In some embodiments, system 1200 includes one or more multi-wavelength optical sensors for detecting the presence of an article and visually imaging the article, as at least one of the sensors 1210, such that the imaging sensor communicates with one or more other components of system 1200.

[0063] System 1200 also includes a storage drive 1212 for storing content such as detected item data. In some embodiments, components 1202, 1204, 1206, 1208, 1210, and 1212 are interconnected by a data transmission system (e.g., a bus) 1214. In some embodiments, certain components (such as sensor 1210) may not be connected to the data transmission system 1214, but may instead be connected to processor 1202 or an interface of processor 1202, or another component, via a wired or wireless connection. A power supply unit (PSU) 1216 supplies power to the components of system 1200 via a power delivery system 1218 (shown together with data transmission system 1214, but the power delivery system and data transmission system may be separate). It should be understood that system 1200 can be configured differently, and each of the listed components may actually represent several different components. For example, CPU 1202 may represent a multiprocessor or distributed processing system; memory unit 1204 may include different levels of cache memory and main memory; I / O device 1206 may include a monitor, keyboard, touchscreen, etc.; at least one network interface 1208 may include one or more network interface cards (NICs) providing one or more wired and / or wireless connections to network 1220; and storage drive 1212 may include hard disks and remote storage locations. Therefore, the configuration of system 1200 is expected to have broad flexibility, ranging from a single physical platform configured primarily for a single user or autonomous operation to a distributed multi-user platform such as a cloud computing system.

[0064] In some implementations, system 1200 may use one or more operating systems, including various versions of operating systems provided by Microsoft (such as Windows), Apple (such as Mac OS X), UNIX, RTOS, and LINUX, and, depending on the purpose of system 1200, may include operating systems specifically developed for handheld devices (e.g., iOS, Android, RTOS, and / or Blackberry), personal computers, servers, and other computing platforms. The operating system, along with other instructions (e.g., instructions for telecommunications and / or other functions provided by system 1200), may be stored in memory unit 1204 and executed by processor 1202. For example, memory unit 1204 may include instructions for causing an article to be conveyed along a path within the device and for performing article identification and authentication using data collected from optical sensors.

[0065] Network 1220 can be a single network or can represent multiple networks, including different types of networks, whether wireless or wired. For example, system 1200 can be coupled to external devices via a network including a cellular link coupled to a packet network, or it can be coupled via a packet link such as a wireless local area network (WLAN) coupled to a packet network or a public switched telephone network (PSTN). Therefore, many different network types and configurations can be used to couple system 1200 to external devices.

[0066] An example embodiment of this disclosure may include a multi-wavelength optical sensor comprising an illuminator for placement in an item detection area. The illuminator includes an illuminator housing, one or more light-emitting diodes (LEDs) of different wavelengths disposed within the illuminator housing, and a light strip disposed within the illuminator housing. The light strip includes a light guide and a diffuser, the diffuser having a thickness and a width corresponding to the shape of the bottom portion of the light guide. Light emitted by the one or more LEDs is reflected within the light guide and scattered by the diffuser through the light guide for transmission to the outside of the illuminator. The multi-wavelength optical sensor also includes a photodetector for placement opposite the illuminator in the item detection area. The photodetector includes a photodetector housing, a photodiode array disposed within the photodetector housing, and an aperture array having a plurality of vertical walls for controlling scattered light transmitted by the illuminator and reducing stray light effects.

[0067] In one or more of the above embodiments, the thickness of the diffuser is the thickness of the bulk material.

[0068] In one or more of the above embodiments, the block material is plastic.

[0069] In one or more of the above embodiments, the photodetector further includes a light diffuser disposed within the photodetector housing and between the aperture array and the illuminator.

[0070] In one or more of the above embodiments, the photodetector further includes a light shield for preventing stray light from entering the photodetector, and wherein the light shield includes a cutout in which a light diffuser of the photodetector is disposed.

[0071] In one or more of the above embodiments, the photodetector further includes a lens array disposed within the photodetector housing and between the photodiode array and the aperture array.

[0072] In one or more of the above embodiments, each photodiode in the photodiode array includes another aperture disposed between the photodiode and the lens array, and wherein the other aperture includes a cutout for controlling the light passing through the lens array and reaching the photodiode.

[0073] In one or more of the above embodiments, at least a portion of the photodetector housing is covered by a protective transparent cover.

[0074] In one or more of the above embodiments, the light guide and the diffuser are made of the same substrate.

[0075] In one or more of the above embodiments, at least a portion of the illuminator housing is covered by a protective transparent cover.

[0076] In one or more of the above embodiments, the light guide includes a sloping side for deflecting light emitted from one or more LEDs into the central portion of the light strip.

[0077] In one or more of the above embodiments, each tilted side of the light guide is covered with a light shield attached thereto to prevent light from leaking to the outside of the light guide.

[0078] In one or more of the above embodiments, one or more LEDs with different wavelengths are arranged in an LED array, which is positioned below the inclined side of the light guide.

[0079] In one or more of the above embodiments, the width of the diffuser of the light stripe, corresponding to the shape of the bottom portion of the light guide, forms an optically inactive transition layer between the diffuser and the light guide.

[0080] Another example embodiment of this disclosure may include a light strip for an optical device, including a light guide and a diffuser, the light guide having an end having a shape for deflecting light into a central portion of the light guide; the diffuser having a thickness and a width corresponding to the shape of the bottom portion of the light guide, wherein light reflected within the light guide is scattered by the diffuser through the light guide for transmission, and wherein the light strip provides a stable illumination indication distribution.

[0081] In one or more of the above embodiments, the thickness of the diffuser is the thickness of the bulk material.

[0082] In one or more of the above embodiments, the block material is plastic.

[0083] In one or more of the above embodiments, each end of the light guide is shaped as an angled shape.

[0084] In one or more of the above embodiments, each end of the light guide is covered with a light shield attached thereto to prevent light from leaking to the outside of the light guide.

[0085] In one or more of the above embodiments, each end of the light guide includes a leg that extends laterally from the corresponding end and is located on both sides of the body of the light guide.

[0086] In one or more of the above embodiments, the width of the diffuser of the light stripe, corresponding to the shape of the bottom portion of the light guide, forms an optically inactive transition layer between the diffuser and the light guide.

[0087] Another example embodiment of this disclosure may include a method comprising: detecting an article in an article detection area of ​​a device by a multi-wavelength optical sensor, wherein the multi-wavelength optical sensor includes an illuminator disposed in the article detection area. The illuminator includes an illuminator housing, one or more light-emitting diodes (LEDs) having different wavelengths disposed within the illuminator housing, and a light strip disposed within the illuminator housing, the light strip including a light guide and a diffuser, the diffuser having a thickness and a width corresponding to the shape of the bottom portion of the light guide. The multi-wavelength optical sensor also includes a photodetector disposed opposite the illuminator in the article detection area. The photodetector includes a photodetector housing, a photodiode array disposed within the photodetector housing, and an aperture array having a plurality of vertical walls. Detecting an article includes: emitting light by one or more LEDs; reflecting the emitted light within the light guide and scattering the light by the diffuser to allow it to pass through the light guide for transmission to the outside of the illuminator; receiving the scattered light transmitted by the illuminator by the photodetector; and controlling the scattered light and reducing stray light effects using the plurality of vertical walls of the aperture array.

[0088] In one or more of the above embodiments, the thickness of the diffuser is the thickness of the bulk material.

[0089] In one or more of the above embodiments, the block material is plastic.

[0090] In one or more of the above embodiments, the method further includes: using a light shield included in the photodetector and disposed between the aperture array and the illuminator to prevent stray light from entering the photodetector, wherein the light shield includes a cutout, a light diffuser of the photodetector is disposed within the cutout, and using the light diffuser to redirect a portion of the scattered light back to the article.

[0091] In one or more of the above embodiments, the photodetector further includes a lens array disposed within the photodetector housing and between the photodiode array and the aperture array.

[0092] In one or more of the above embodiments, each photodiode in the photodiode array includes another aperture disposed between the photodiode and the lens array, and the method further includes using a cutout included in the other aperture to control the light passing through the lens array and reaching the photodiode.

[0093] In one or more of the above embodiments, at least a portion of the photodetector housing is covered by a protective transparent cover, and at least a portion of the illuminator housing is covered by a protective transparent cover.

[0094] In one or more of the above embodiments, the method further includes: using a tilted side of the light guide to deflect light emitted from one or more LEDs into the central portion of the light guide.

[0095] In one or more of the above embodiments, the method further includes using a light shield attached to each tilted side of the light guide to prevent light leakage to the outside of the light guide.

[0096] In one or more of the above embodiments, one or more LEDs with different wavelengths are arranged in an LED array, which is positioned below the inclined side of the light guide.

[0097] In one or more of the above embodiments, the width of the diffuser of the light stripe, corresponding to the shape of the bottom portion of the light guide, forms an optically inactive transition layer between the diffuser and the light guide.

[0098] While this disclosure has described certain embodiments and generally associated methods, variations and modifications to these embodiments and methods will be apparent to those skilled in the art. Therefore, the above description of exemplary embodiments does not limit or constrain this disclosure. Other changes, substitutions, and modifications are possible without departing from the spirit and scope of this disclosure as defined by the appended claims.

[0099] The descriptions in this application should not be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the patentable subject matter is defined solely by the claims. Furthermore, unless the exact wording “means for” is followed by a participle, no claim is intended to invoke 35 USC §112(f).

Claims

1. A multi-wavelength optical sensor, comprising: An illuminator, the illuminator being positioned in the item detection area, the illuminator comprising: Lighting fixture housing; One or more light-emitting diodes (LEDs) with different wavelengths, said one or more LEDs being disposed within the illuminator housing; and A light strip, wherein the light strip is disposed in the housing of the illuminator, the light strip comprising: Optical guide; and A diffuser having a thickness and a width corresponding to the shape of the bottom portion of the light guide, wherein light emitted by one or more LEDs is reflected within the light guide and scattered by the diffuser through the light guide for transmission to the outside of the illuminator.

2. The multi-wavelength optical sensor according to claim 1 further includes: A photoelectric detector, configured to be positioned opposite the illuminator in the item detection area, the photoelectric detector comprising: Photodetector housing; A photodiode array, wherein the photodiode array is disposed within the photodetector housing; and An aperture array having multiple vertical walls for controlling the scattered light transmitted by the illuminator and reducing stray light effects.

3. The multi-wavelength optical sensor according to claim 2, wherein the photodetector further includes a light diffuser, the light diffuser being disposed within the photodetector housing and between the aperture array and the illuminator.

4. The multi-wavelength optical sensor according to claim 3, wherein the photodetector further includes an optical shield for preventing stray light from entering the photodetector, and wherein the optical shield includes a cutout, and the light diffuser of the photodetector is disposed within the cutout.

5. The multi-wavelength optical sensor according to claim 2, wherein the photodetector further includes a lens array, the lens array being disposed within the photodetector housing and between the photodiode array and the aperture array.

6. The multi-wavelength optical sensor of claim 5, wherein each photodiode in the photodiode array includes another aperture disposed between the photodiode and the lens array, and wherein the other aperture includes a cutout for controlling the light passing through the lens of the lens array and reaching the photodiode.

7. The multi-wavelength optical sensor of claim 2, wherein at least a portion of the photodetector housing is covered by a protective transparent cover.

8. The multi-wavelength optical sensor according to claim 1, wherein the light guide and the diffuser are made of the same substrate.

9. The multi-wavelength optical sensor of claim 1, wherein at least a portion of the illuminator housing is covered by a protective transparent cover.

10. The multi-wavelength optical sensor of claim 1, wherein the light guide includes a tilted side for deflecting light emitted from the one or more LEDs into a central portion of the light guide.

11. The multi-wavelength optical sensor of claim 10, wherein each of the sloped sides of the light guide is covered with a light shield attached thereto to prevent light leakage outside the light guide.

12. The multi-wavelength optical sensor of claim 11, wherein the one or more LEDs having different wavelengths are arranged in an LED array, the LED array disposed under the sloped sides of the light guide.

13. The multi-wavelength optical sensor of claim 1, wherein a width of the diffuser of the light bar corresponding to a shape of the bottom portion of the light guide forms an optically inactive transition layer between the diffuser and the light guide.

14. A light bar for an optical device, comprising: a light guide having end portions with a shape for deflecting light into a central portion of the light guide; and a diffuser having a thickness and a width corresponding to a shape of a bottom portion of the light guide, wherein light reflected within the light guide is scattered by the diffuser through the light guide for transmission, and wherein the light bar provides a stable illumination indication profile.

15. The light bar of claim 14, wherein the shape of each end portion of the light guide is a sloped shape.

16. The light bar of claim 15, wherein each end portion of the light guide is covered with a light shield attached thereto to prevent light leakage outside the light guide.

17. The light bar of claim 14, wherein each end portion of the light guide includes a leg portion extending laterally from the respective end portion and located on either side of a main body of the light guide.

18. The light bar of claim 14, wherein a width of the diffuser of the light bar corresponding to a shape of the bottom portion of the light guide forms an optically inactive transition layer between the diffuser and the light guide.

19. A method, comprising: detecting, by a multi-wavelength optical sensor, an item in an item detection area of a device, wherein the multi-wavelength optical sensor includes: an illuminator disposed in the item detection area, the illuminator including: an illuminator housing; one or more light emitting diodes (LEDs) having different wavelengths disposed in the illuminator housing; and a light bar disposed in the illuminator housing, the light bar including: a light guide; and a diffuser having a thickness and a width corresponding to a shape of a bottom portion of the light guide; and a photodetector disposed opposite the illuminator in the item detection area, the photodetector including: a photodetector housing; a photodiode array disposed within the photodetector housing; and a diaphragm array having a plurality of vertical walls; wherein detecting the item includes: emitting light by the one or more LEDs; reflecting the emitted light within the light guide and scattering the light by the diffuser through the light guide for transmission outside the illuminator; and ​ The photodetector receives the scattered light transmitted by the illuminator, and the plurality of vertical walls of the aperture array are used to control the scattered light and reduce stray light effects.

20. The method of claim 19, wherein the width of the diffuser of the light stripe corresponding to the shape of the bottom portion of the light guide forms an optically inactive transition layer between the diffuser and the light guide.

Images