Patent ID: 6382512
Filing Date: 2002-05-07
Classification: G06K

Abstract:
A signal control apparatus for a barcode scanner consisting of a decoder and a laser engine, the laser engine comprising:a laser beam output for generating light to project on an object; a light detect sensor for receiving a reflection signal from the object and converting the reflection signal to an electric characteristic signal output by the light detect sensor; an analog circuit for amplifying the electric characteristic signal output by the light detect sensor, a tone decoder for receiving the amplified signal from the analog circuit, confirming if the reflection signal is same as an emitting signal to avoid wrongful judgement or cause wrongful action, and to output at a constant level transformation state after confirmation; a time delay for delaying an output signal from the tone decoder; a flip flop for receiving the output signal from the time delay to lock or open the flip flop; an oscillation circuit for generating an oscillatory frequency output signal; and a scanner structure for receiving the oscillatory frequency output signal and driving the scanner to start scanning operation; wherein the tone decoder sends out a control signal to the laser engine for enabling a scan enable and a laser enable while the scanner structure of the laser engine remains non-activated such that a start of a scan signal and a synchronously reading signal that has been sent to the decoder is not sent out, the oscillation circuit sending out an oscillatory wave through a first output pin, and wherein at an initial stage when no object is located at front, the light detect sensor receives no reflection signal and a second output pin is at a low electric level, the oscillator frequency output signal being applied on the laser beam output for emission; and wherein when an object enters a readable range and causes reflection of an emitting photo signal which is converted to an electrical signal through the light detect sensor and forwarded to the analog circuit for amplification processing, the amplified signal is transmitted to the tone decoder which confirms if the reflection signal is the same as the emitting signal, and through the time delay controls the flip flop at a lock state so that the second output pin reaches a high electric level, and so that the laser diode is at a constant current operation state, the scanner structure starting operation and laser photo points being scanned in a linear fashion for sending out a start of scan signal for reading the barcode data output.