1. Field of the Invention
This invention generally relates to electro-optical systems for reading indicia of different light reflectivity such as bar code symbols and, more particularly, to mountable bar code readers.
2. Description of Related Art
Laser scanner systems and components of the type exemplified by U.S. Pat. Nos. 4,251,798; 4,360,798; 4,369,361; 4,387,297; 4,593,186; 4,496,831; 4,409,470; 4,460,120; 4,607,156; 4,673,803; 4,736,095; 4,758,717; 4,816,660; 4,808,804; 4,816,661; 4,760,248; 4,871,904; 4,806,742; 4,825,057; 4,835,374; and 4,845,350, as well as U.S. application Ser. No. 08/400,840 filed Mar. 8, 1995xe2x80x94all of said patents and patent applications being owned by the assignee of the instant invention and being incorporated by reference hereinxe2x80x94have generally been designed to read indicia having parts of different light reflectivity, e.g., bar code symbols, particularly of the Universal Product Code (UPC) type, at a certain working or reading distance from a hand-held or stationary scanner.
Typically, a light source such as a laser generates a light beam which is optically modified and focused to form a beam spot of a certain size at a working distance relative to a housing and is directed by optical components, including a reflecting mirror, along a light path through an exit port of the housing toward a bar code symbol located in the vicinity of the working distance for reflection from the symbol. A photodetector having a field of view extending across and slightly past the symbol detects a light of variable intensity reflected off the symbol and generates electrical signals indicative of the detected light. These electrical signals are decoded into data descriptive of the symbol. A scanning component may be situated in the housing, and is operative to either sweep the beam spot in a scan pattern across the symbol, or to scan the field of view of the photodetector, or simultaneously do both.
The components for the light scanning system, including the light source, optics, photodetector, scanning component and an electrical conductor, are mounted together in a common assembly to constitute a compact, lightweight, scan module. The scan module is mounted in an interchangeable, modular manner in housings of different configurations.
For example, the housing can be hand-held and shaped as a cylinder in a so-called flashlight-type configuration, or shaped as a box, or shaped with a gun-like configuration. The housing can be mounted on the back of an operator""s arm (see, for example, U.S. Pat. No. 4,766,299) or on one or more fingers of the operator""s hand, typically with the aid of a strap, a clip, or a glove. The housing can be mounted on the operator""s arm, typically adjacent or on the wrist. The housing can be mounted in a countertop workstation. The housing can be mounted in a mobile cart, or shopping cart, or, in some cases, even in a stationary installation.
The compact, lightweight nature of the scan module enables myriad other housing configurations to be fashioned. Thus, the scan module can be mounted anywhere on an operator""s person, e.g. in a helmet to be worn on the operator""s head, in eyeglasses to be worn in front of the operator""s eyes, in a shoulder or body harness, etc.
It is a general object of this invention to advance the state of the art electro-optical systems for reading indicia of different light reflectivity, particularly laser scanner systems for reading bar code symbols.
Another object of this invention is to simplify operation of bar code readers.
In keeping with these objects, and others which will become apparent hereinafter, one feature of this invention resides, briefly stated, in an electro-optical system for reading indicia having parts of different light reflectivity, e.g. bar code symbols having alternating bars and spaces.
In one preferred embodiment, the bar code reader of the invention comprises actuatable electro-optical scanning means for projecting a light beam onto a bar code symbol to be read, for scanning the bar code symbol, and for detecting light of variable intensity that is reflected off the bar code symbol to generate an electrical signal representative of the bar code symbol. Also, in the bar code reader, activation means activates the scanning means to initiate reading of the bar code symbol when an object bearing the bar code symbol is proximate to the scanning means. The reader also includes mounting means for mounting the scanning means and the activation means onto an operator to operate the bar code reader. The mounting means can comprise, for example, a glove, a helmet, eyeglasses, a strap, a clip, a shoulder harness, or a body harness.
In another embodiment, the system of the invention comprises a scanning system for reading indicia having parts of different light reflectivity, comprising a housing, a light beam generator and scanner provided in the housing for scanning a beam across the indicia, and a detector provided in the housing responsive to light reflected from the indicia for generating an electrical signal representative of the indicia. Activation means provided in the housing activates the light beam generator and scanner when an object bearing the indicia is proximate to the reader. Also, mounting means mounts the housing onto an operator to operate the bar code reader.
In still another embodiment, a method of the invention comprises the steps of scanning a light beam across a bar code symbol using a bar code reader when an object bearing the bar code symbol is within a predetermined distance of the reader; detecting the light reflected from the bar code symbol; and generating electrical signals representative of the bar code symbol in accordance with the detected light.