Optics: measuring and testing – Photometers – Integrating spheres
Reexamination Certificate
1999-09-03
2001-04-24
Font, Frank G. (Department: 2877)
Optics: measuring and testing
Photometers
Integrating spheres
C250S228000
Reexamination Certificate
active
06222623
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention pertains to light mixer arrangements for providing substantially homogenous light spots. In particular, implementations of document validation subsystems utilizing a light mixer for generating substantially homogenous light spots, and methods of construction are described.
In the field of bill validation, validators used in vending machines and the like typically utilize optical, magnetic and other sensors to obtain data from an inserted bill. In some units, a plurality of light-emitting diode (LED) light sources and phototransistor receivers are positioned on opposite sides of a bill passageway, and generate a plurality of signals corresponding to the light transmitted through the bill as a bill moves past. The signals are processed to determine certain information, such as the position of the bill in the passageway and the authenticity of the bill. The signals are typically compared to predetermined measurements stored in memory that correspond to genuine bills.
Prior art systems utilizing LED light sources also used lenses to focus the light in order to meet system performance requirements. However, some configurations did not provide sufficient light signal levels to accurately validate documents. Further, designs using high power light sources and focusing elements are costly to manufacture.
SUMMARY OF THE INVENTION
A document validation subsystem having a light mixer for generating at least one substantially homogenous light spot is presented. The light mixer includes a light mixing chamber, at least one input port associated with the mixing chamber to accommodate at least one light source, at least one output associated with the mixing chamber, at least one collimator connected to the output, and at least one light receiver.
Implementations of the invention may include one or more of the following features. The light mixing chamber may include a diffuse reflective liner applied to an interior surface of the chamber. The collimator may include a mirror, and the input port may house a plurality of LED light sources. At least two light sources connected to the input port may be of different wavelengths, or may be of the same wavelength. The LED light sources may be operable to turn ON sequentially or simultaneously. A plurality of output apertures may be associated with the mixing chamber, and a plurality of collimators may be connected to the output apertures to generate substantially homogenous light spots. In addition, at least one of the collimators may include a lens, and at least one lens component may be attached to an upper platen of a document passageway.
In another implementation, a method for constructing a document validation subsystem is described. The method includes constructing a light mixer for generating at least one substantially homogenous light spot, connecting a light source to the light mixer, connecting the light mixer and source to a wall of a document passageway, and connecting a light receiver to a wall of the document passageway to receive a light signal resulting from the substantially homogenous spot.
Implementations of the method may include one or more of the following features. The light mixer may be constructed by molding a chamber having at least one input port and at least one output aperture, applying a diffuse reflective coating to an interior surface of the chamber, and connecting at least one collimator to at least one output aperture. The chamber may be cast in two hemispheres. The method may include attaching at least one mirror to the collimator for directing light, and may include attaching at least one lens to the collimator. The light mixer may be constructed by molding a light mixing chamber using an optical plastics material, wherein the chamber includes at least one input port and at least one output aperture, and connecting at least one collimator to at least one output aperture.
Another implementation of a modular light mixer assembly includes a plurality of light mixers, each having at least one input port, at least one output aperture and at least one collimator connected to an aperture. The light mixers are arranged to provide light spot output coverage across the width of a document passageway. Included are a plurality of light sources, wherein at least one light source is connected to each input port, and at least one light receiver for sensing light generated by the light spots and for generating document validation signals.
Another implementation of a light mixer assembly for use with a document validator includes a plurality of light mixers, each having at least one input port, at least one output aperture and at least one collimator connected to an aperture. The light mixers are arranged to provide light spot output coverage across the width of a document passageway. Also included are a plurality of light sources, wherein at least one light source is connected to each input port, and at least one light receiver for sensing the light spots and for generating document validation signals.
Another aspect of the invention is a document validator subassembly that includes a cylinder having a cavity and at least one input port and a slit output. A reflective and diffusive coating is applied to the cavity. Included are at least one collimator aligned with the slit output, at least one light source connected to the input port, and at least one light receiver.
In another implementation, a document validator subassembly includes a cylinder having a cavity and at least one input port and a plurality of output apertures for generating a plurality of substantially homogenous light spots. A reflective and diffusive coating is applied to the cavity. Included are a plurality of collimators attached to the output apertures, at least one light source connected to the input port, and at least one light receiver. This implementation may include at least one light pipe connected at a first end to an output aperture and at a second end to a collimator.
In another implementation of a document validator subassembly, a block of optical material having a cavity that includes an internally reflecting and diffuse surface is used. The block of material includes at least one input port and at least one output aperture. At least one collimator is attached to the output aperture for generating at least one substantially homogenous output spot, at least one light source is connected to the input port, and at least one receiver is included.
Another implementation of a document validator subassembly includes a block of optical material having a cavity that includes an internally reflecting and diffuse surface, at least one input port and at least one output aperture. The subassembly includes at least one collimator attached to the output aperture for generating at least one substantially homogenous output spot, at least one light source connected to the input port, and at least one receiver.
Another aspect is a method for constructing a document validator subassembly. The method includes connecting a light mixer to a wall of a document passageway, the light mixer capable of generating at least one substantially homogenous light spot. The light mixer is formed by cutting a cavity into a block of optical material, wherein the cavity has reflective and diffuse characteristics, forming at least one input port and at least one output aperture that connect to the cavity, connecting at least one light source to each input port, and connecting at least one collimator to an output aperture. The method also includes connecting at least one light receiver to a wall of the document passageway to receive light resulting from the substantially homogenous light spot.
In yet another implementation, a document validator subassembly includes a light mixer for generating at least one substantially homogenous light spot. The light mixer includes a solid core light mixing chamber having an outside coating with diffuse and reflective characteristics. The coating includes at least one input area for accommodating at least one lig
Fish & Richardson P.C.
Font Frank G.
Lauchman Layla
Mars Incorporated
LandOfFree
Integrating light mixer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Integrating light mixer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Integrating light mixer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2538493