Optical scan pattern generator for code reading systems
Code read-out means
Optical scanning system for universal product code
Electro-optical bar-code scanning unit
Method and apparatus for controlling the intensity of a laser output beam
Frequency modulated electrical discharge laser
Power limiting circuit for bar code reader
Instrument for measurement of exposure from a laser radiation
Method for controlling the operation of an optical scanner
ApplicationNo. 06/665276 filed on 10/26/1984
US Classes:250/555, Including coded record235/455, Light level control235/462.25Reader processing circuitry
ExaminersPrimary: Nelms, David C.
Attorney, Agent or Firm
International ClassG06K 7/10 (20060101)
AbstractIn order to meet the requirements for laser radiation safety, namely laser output which can enter the naked human eye indefinitely and cause no discernible damage (Class I emission limit) in a code symbol (bar code) scanner, a mode controller is used for generating a laser enabling the signal so as to turn the laser on in a search mode until the symbols are acquired and in an in-code mode while the symbols are being scanned. When the laser is turned on it operates at a power output which would exceed the Class I emission limits if operated continuously. Circuitry is provided for operating the mode controller so that the laser is not enabled to turn on for a period long enough to exceed Class I limits. Such circuitry may be an integrator or accumulator which responds to the time that the mode controller turns the laser on and which provides an output for inhibiting the mode controller from turning the laser on for a period of time sufficient to prevent the Class I emission limit from being exceeded. The circuitry may alternatively be a pulse generator which permits the mode controller to turn the laser on repetetively during a "find paper" mode with a duty cycle such that the Class I emission limits are not exceeded.