Patent Application
20120168513
The present disclosure relates to bar code imagers and methods of illumination used in such devices.
A bar code is a representation of data, such as, for instance, an optical machine-readable representation of data. For example, a bar code can represent data using a number of parallel lines and/or the spacing between the lines. Such a bar code can be referred to as a one-dimensional bar code.
As an additional example, a bar code can represent data using a number of geometrical shapes and or patterns, such as, for instance, squares, dots, and/or hexagons, among other geometrical shapes and/or patterns. Such a bar code can be referred to as a two-dimensional bar code.
A bar code can be used to represent data associated with a product or products. For example, a bar code representing data associated with a product(s) can be placed on the product(s) (e.g., on the packaging of the product(s) or on the container containing the product(s)).
A bar code imager can be used to create an image of a bar code. The bar code imager can create the image of the bar code by, for example, illuminating the bar code in the case of a low ambient light environment. The image of the bar code can then be used to determine (e.g., read) the data represented by the bar code.
The illumination module of a bar code imager can include, for example, a light-emitting diode (LED) only, or also can include a lens. Light emitted by the LED can illuminate a bar code located near (e.g., a few inches from) the bar code imager to create an image of the bar code.
However, a bar code imager illumination module consisting only of an LED may not effectively illuminate a bar code located farther away from (e.g., at least two feet from) the bar code imager, such as, for instance, a bar code on a product located on a shelf in a warehouse. For instance, the large divergence of an LED can greatly reduce the irradiance at large ranges.
A lens may be used to reduce the divergence and hence increase the irradiance at large ranges. However, LEDs can have electrode traces that cause the emitting area of the LED to have a patterned radiance. When such an LED is used with a lens, the illumination of a bar code (e.g., the irradiance at a bar code) located farther away from the bar code imager may not be substantially uniform (e.g., may not be distributed substantially uniformly). For instance, the illumination of a bar code located farther away from the bar code imager may be a structured illumination (e.g., some portions of the bar code may be less illuminated than others).
Because a bar code imager using a lens to image an LED on to the bar code may not effectively illuminate a bar code located farther away from (e.g., at least two feet from) the bar code, such a bar code imager may create an inaccurate and/or incomplete image of a bar code located farther away from the bar code imager.
Bar code imagers and methods of operating bar code imagers are described herein. One or more embodiments include a lens, wherein the lens has a focal length associated therewith, and a light-emitting diode, wherein the light-emitting diode is located within the focal length associated with the lens.
Bar code imagers in accordance with one or more embodiments of the present disclosure can effectively illuminate and/or create an accurate and/or complete image of a bar code from farther away than previous bar code imagers. For example, a bar code imager in accordance with one or more embodiments of the present disclosure can effectively illuminate and/or create an accurate and/or complete image of a bar code that is at least two feet from the bar code imager, such as, for instance, a bar code on a product located on a shelf in a warehouse.
As an example, the illumination of a bar code located at least two feet from a bar code imager in accordance with one or more embodiments of the present disclosure may be substantially uniform across the bar code. That is, the irradiance at a surface of the bar code may be distributed substantially uniformly across the surface of the bar code. For instance, the illumination of a bar code located at least two feet from a bar code imager in accordance with one or more embodiments of the present disclosure may be a non-structured illumination (e.g., substantially all portions of the bar code may be illuminated approximately equally).
In the following detailed description, reference is made to the accompanying drawings that form a part hereof. The drawings show by way of illustration how one or more embodiments of the disclosure may be practiced. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to practice one or more embodiments of this disclosure. It is to be understood that other embodiments may be utilized and that process, electrical, and/or structural changes may be made without departing from the scope of the present disclosure.
As will be appreciated, elements shown in the various embodiments herein can be added, exchanged, combined, and/or eliminated so as to provide a number of additional embodiments of the present disclosure. The proportion and the relative scale of the elements provided in the figures are intended to illustrate the embodiments of the present disclosure, and should not be taken in a limiting sense.
As used herein, “a” or “a number of” something can refer to one or more such things. For example, “a number of mirrors” can refer to one or more mirrors.
Lens 102 can have a focal point 106 associated therewith, as illustrated in
Lens 102 can also have a focal length f associated therewith, as illustrated in
As shown in
LED 104 can be located a distance d1 from focal point 106, as illustrated in
Lens 102 can be a movable lens. That is, the position of lens 102 can be moved (e.g., translated) within bar code imager 100. Moving the position of lens 102 may move the position of focal point 106. That is, moving the position of lens 102 may change the distance d1 between LED 104 and focal point 106. For example, defocusing lens 102 (e.g., moving lens 102 to the left) in the embodiment illustrated in
In the embodiment illustrated in
Lens 102 can have a numerical aperture (e.g., range of angles over which lens 102 can receive and/or emit light) of, for example, approximately 0.64. Lens 102 can also have a chromatic aberration (e.g., chromatic distortion) of, for example, approximately 5.1 millimeters. Such a numerical aperture and/or chromatic aberration can, for example, increase the effectiveness (e.g., the illumination effectiveness) and/or decrease the size of bar code imager 100. However, embodiments of the present disclosure are not limited to a particular numerical aperture or chromatic aberration.
LED 104 can be, for example, a thin film LED (e.g., LED 104 can include a thin film material). For instance, LED 104 can be a high power enhanced thin film LED. Such LED types can, for example, increase the effectiveness (e.g., the illumination effectiveness) and/or decrease the size of bar code imager 100. However, embodiments of the present disclosure are not limited to a particular type of LED.
In the embodiment illustrated in
Although not shown in
As shown in
In one or more embodiments of the present disclosure, the illumination of bar code 108 can be substantially uniform across bar code 108. That is, the irradiance at the surface of bar code 108 can be distributed substantially uniformly across the surface of bar code 108. For instance, the illumination of bar code 108 can be a non-structured illumination (e.g., substantially all portions of bar code 108 can be illuminated approximately equally). Because the illumination of bar code 108 can be substantially uniform across bar code 108, bar code imager 100 can effectively illuminate bar code 108 and/or create an accurate and/or complete image of bar code 108.
Bar code 108 can be located a distance d2 from bar code imager 100 (e.g., from lens 102), as illustrated in
The distance d2 between bar code imager 100 and bar code 108 (e.g., the distance d2 at which bar code imager 100 can effectively illuminate bar code 108 and/or create an accurate and/or complete image of bar code 108) can be greater than the distance at which previous bar code imagers can effectively illuminate bar codes and/or create accurate and/or complete images of bar codes. For example, the distance d2 at which bar code imager 100 can effectively illuminate bar code 108 and/or create an accurate and/or complete image of bar code 108 can be at least two feet, as previously described herein. In contrast, the distance at which previous bar code imagers can effectively illuminate bar codes and/or create accurate and/or complete images of bar codes can be a few inches, as previously described herein.
Lens 212-1 can have a focal point 216-1 and a focal length f associated therewith, and lens 212-2 can have a focal point 216-2 and a focal length f associated therewith, as illustrated in
Although lenses 212-1 and 212-2 have the same focal length (e.g., f) in the embodiment illustrated in
As shown in
LED 214-1 can be located a distance d1 from focal point 216-1, and LED 214-2 can be located a distance d1 from focal point 216-2, as illustrated in
Although the distance between LED 214-1 and focal point 216-1 is the same as the distance between LED 214-2 and focal point 216-2 in the embodiment illustrated in
Lens 212-1 and/or lens 212-2 can be analogous to lens 102 previously described in connection with
LED 214-1 and/or LED 214-2 can be analogous to LED 104 previously described in connection with
LED 214-2 can be located a distance of, for example, approximately 8.32 millimeters from LED 214-1. For instance, the center of LED 214-2 can be located a distance of approximately 8.32 millimeters from the center of LED 214-1. Such a distance can, for example, increase the effectiveness (e.g., the illumination effectiveness) and/or decrease the size of bar code imager 201. However, embodiments of the present disclosure are not limited to a particular distance between LED 214-1 and/or LED 214-2.
In the embodiment illustrated in
In the embodiment illustrated in
Although not shown in
Although the embodiment illustrated in
As shown in
The collimated light can be directed to illuminate a bar code 218, as illustrated in
In one or more embodiments of the present disclosure, the illumination of bar code 218 can be substantially uniform across bar code 218, in a manner analogous to that previously described in connection with
Bar code 218 can be located a distance d2 from bar code imager 201 (e.g., from lens 212-1 and lens 212-2), as illustrated in
Including multiple lenses and multiple LEDs (e.g., lenses 212-1 and 212-2, and LEDs 214-1 and 214-2) in bar code imager 201 can further increase the range of bar code imager 201. For example, the multiple lenses and multiple LEDs can increase the amount (e.g., intensity) of light emitted by bar code imager 201 and/or the illumination of bar code 218 (e.g., the irradiance at bar code 218), which can further increase the distance d2 at which bar code imager 201 can effectively illuminate bar code 218 and/or create an accurate and/or complete image of bar code 218.
Another benefit of multiple lenses and multiple LEDs embodiments can include illuminating and/or imaging larger bar codes based upon directing the light emitted by the multiple LEDs to multiple areas. In some embodiments, the areas can be adjacent.
Although the distance between lens 212-1 and bar code 218 is the same as the distance between lens 212-2 and bar code 218 in the embodiment illustrated in
Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art will appreciate that any arrangement calculated to achieve the same techniques can be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments of the disclosure.
It is to be understood that the above description has been made in an illustrative fashion, and not a restrictive one. Combination of the above embodiments, and other embodiments not specifically described herein will be apparent to those of skill in the art upon reviewing the above description.
The scope of the various embodiments of the disclosure includes any other applications in which the above structures and methods are used. Therefore, the scope of various embodiments of the disclosure should be determined with reference to the appended claims, along with the full range of equivalents to which such claims are entitled.
In the foregoing Detailed Description, various features are grouped together in example embodiments illustrated in the figures for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the embodiments of the disclosure require more features than are expressly recited in each claim.
Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.
