Symbol read device

Claim 2

A symbol read device according to claim 1 further comprising: means for modulating the light beam with a first frequency; and means for modulating light from the second light source with a second frequency different from the first frequency; first filter means coupled between the first detecting means and recognizing means the for filtering the first signal by passing the first frequency and rejecting other frequencies; and second filter means coupled between the second detecting means and the controlling means for filtering the second signal for picking up a component of the second frequency by passing the second frequency and rejecting other frequencies.

Claim 3

A symbol read device according to claim 1 wherein the light beam has a first wavelength, light from the second light source has a second wavelength, the first detecting means is responsive to light of the first wavelength, and the second detecting means is responsive to light of the second wave length.

Claim 4

A symbol read device comprising: means for emitting a light beam; means for scanning the light beam over a surface bearing a symbol to be read; a second light source, separate and distinct from the light beam emitting means for illuminating the surface; means for detecting light reflected from the symbol surface and generating a detection signal indicative thereof; recognizing means for processing the detection signal so as to recognize the symbol to be read; signal separating means for separating the detection signal into components thereof corresponding to light from the light beam emitting means and to light from the responsive to light emitted by the laser beam emitting means and a component responsive to light from the second light source, and applying the components corresponding to light from the light beam emitting means to the recognizing means; and controlling means, responsive to the component corresponding to light from the second light source, for controlling the light beam emitting means and the scanning means.

Claim 5

A symbol read device comprising: means for emitting a light beam; means for modulating the light beam with a first frequency; and means for scanning the modulated light beam over a surface bearing a symbol to be read; a second light source, separate and distinct from the light beam emitting means for illuminating the surface; means for modulating light from the second light source with a second frequency different from the first frequency, controlling means, for controlling the light beam emitting means and the scanning means; means for detecting light reflected from the symbol surface and generating a detection signal indicative thereof; recognizing means for processing the detection signal so as to recognize the symbol to be read; and signal separating means for separating the detection signal into a first component part corresponding to light from the light beam emitting means and a second component part corresponding to light from the second light source and coupling the first component part to the recognizing means.

Claim 6

A symbol read device comprising: means for emitting a light beam; means for modulating the light beam with a first frequency; and means for scanning the modulated light beam over a surface bearing a symbol to be read; a second light source, separate and distinct from the light beam emitting means for illuminating the surface; means for modulating light from the second light source with a second frequency different from the first frequency, controlling means for selectively driving the light beam emitting means and the second light source; means for detecting light reflected from the symbol surface and generating a detection signal indicative thereof; recognizing means for processing the detection signal so as to recognize the symbol to be read; and signal separating means for which portions of the detection signal are attributable to light from the light beam emitting means and to the second light source means, the signal separating means including selecting means for 1) when the light beam emitting means is driven, applying the detection signal to the recognizing means, and 2) when the second light source is driven, applying the detection signal to the controlling means.

Claim 7

A symbol read device comprising: means for emitting a light beam; means for scanning with the light beam a symbol surface bearing a symbol to be read, the scanning occurring in at least first and second scan directions; detecting means for detecting light reflected from the symbol surface and generating a detection signal indicative thereof; scan direction detecting means for determining a scan direction of the scanning means; beam emitting control means for selectively controlling the light beam emitted by the light beam emitting means such that it has a first characteristic when the symbol surface is scanned in the first direction and the light beam has a second characteristic when the symbol surface is scanned in the second direction; and a select means for causing the symbol read device to operate in either a first mode wherein the beam emitting means is controlled by the beam emitting control means or in a second mode wherein the output of the beam emitting means is not controlled by the beam emitting control means.

Claim 8

A symbol read device comprising: means for emitting a light beam; means for scanning the light beam in at least first and second directions over a symbol surface bearing a symbol to be read; detecting means for detecting light reflected from the symbol surface and generating a detection signal indicative thereof; scan direction detecting means for detecting the scan direction of the scanning means; beam emitting control means for controlling the beam emitting means responsive to a pulse signal of a first frequency when the symbol surface is scanned in the first direction, and for the operating the beam emitting means responsive to a pulse signal of a second frequency different from the first frequency when the symbol surface is scanned in the second direction; filter means for extracting a first frequency component of the detection signal; and    select means for causing the symbol read device to operate either in a first mode wherein the output of the beam emitting means is controlled by the beam emitting control means or in a second mode wherein the output of the beam emitting means is not controlled by the beam emitting control means and the frequency of the pulse signal to turn on the beam emitting means is fixed at the first frequency.

Claim 9

A symbol read device according to claim 8 further comprising: a select means for causing scanning to occur in a particular scan direction.

Claim 10

A symbol read device comprising: means for emitting a light beam; means for scanning the light beam over different positions on a symbol surface bearing a symbol to be read; detecting means for detecting light reflected from the symbol surface and generating a detection signal indicative thereof; a variable gain amplifier means for amplifying the detection signal; recognizing means signal processing an amplified detection signal from the amplifier and recognizing therefrom the symbol being read; automatic gain control (AGC) means for setting a gain of the variable gain amplifier means every scan line or scan line group including a preset number of scan lines, in response to the detection signal; scan position detecting means for detecting a scan position; and control means for selecting the gain set by the AGC means, based on an output signal of the scan position detecting means.

Claim 11

A symbol read device according to claim 10, wherein the AGC means comprises: a gain control circuit corresponding to each scan direction, an output of the gain control circuit controlling wherein the gain of a variable gain amplifier is determined by its output signal.

Claim 12

A symbol read device according to claim 11 further comprising: a select means for controlling an operational mode of the AGC means including means for controlling the gain of a gain control circuit corresponding to a detection signal related to a specific scan line.

Claim 13

A symbol read device according to claim 10, wherein: the AGC means comprises a single variable gain amplifier for all the scan directions such that variable gain amplifier output information is stored in memory interlocked with each scan direction to control the output signal of the variable gain amplifier.

Claim 14

A symbol read device comprising: first light source means for emitting first light in the form of a light beam; scanning means for scanning a symbol surface containing a symbol to be read with the light beam from the first light source; second light source means for emitting second light for illuminating the symbol surface; first detector means for receiving second light, reflected from the symbol surface; a first filter for filtering the first detector signal; recognizing means for signal processing a signal from the second detector means so as to recognize the symbol being read; a second filter for filtering the second detector signal; and control means for controlling, responsive to a signal from the second filter, the first and second light sources and the scanning means.

Claim 15

A symbol read device according to claim 14, further comprising: means for modulating the first light with a first frequency; and means for modulating the second light with a second frequency different from the first frequency, the first filter having a pass band including the first frequency and the second filter having a pass band including the second frequency.

Claim 16

A symbol read device according to claim 14, wherein the first light has a first wavelength; and the second light has second wavelength different from the first wavelength, the first filter having a pass band including the first wavelength and the second filter having a pass band including the second wavelength.

Claim 17

A symbol read device according to claim 14 further comprising a manually operable switch for controlling the control means so as to override a controlling signal from the second filter.

Claim 18

A symbol read device comprising:    first light source means for emitting first light in the form of a light beam modulated by a first frequency; scanning means for scanning a symbol surface containing a symbol to be read with the light beam from the first light source; second light source means for emitting second light modulated by a second frequency for illuminating the symbol surface; detector means for receiving first and second light, reflected from the symbol surface and providing a detector signal indicative thereof; a first filter having a pass band including the first frequency for filtering the detector signal and providing a first filtered signal responsive to the first light; recognizing means for signal processing a signal from the first filter so as to recognize the symbol being read; a second filter having a pass band including the second frequency for filtering the second detector signal; and control means for controlling, responsive to a signal from the second filter, the first and second light sources and the scanning means.

Claim 19

A symbol read device according to claim 18 further comprising a manually operable switch for controlling the control means so as to override a controlling signal from the second filter.

Claim 20

A symbol read device comprising: first light source means having a first wavelength for emitting first light in the form of a light beam; scanning means for scanning a symbol surface containing a symbol to be read with the light beam from the first light source; second light source means for emitting second light having a second wavelength for illuminating the symbol surface; detector means for receiving first and second light, reflected from the symbol surface and providing a detector signal indicative thereof; a first filter having a pass band including the first wavelength for filtering the detector signal and providing a first filtered signal responsive to the first light; recognizing means for signal processing a signal from the first filter so as to recognize the symbol being read; a second filter having a pass band including the second wavelength for filtering the second detector signal; and control means for controlling, responsive to a signal from the second filter, the first and second light sources and the scanning means.

Claim 21

A symbol read device according to claim 20 further comprising a manually operable switch for controlling the control means so as to override a controlling signal from the second filter.

Claim 22

A symbol read device comprising: first light source means for emitting first light in the form of a light beam; scanning means for scanning a symbol surface containing a symbol to be read with the light beam from the first light source; second light source means for emitting second light for illuminating the symbol surface; detector means for receiving first and second light, reflected from the symbol surface and providing a detector signal indicative thereof; recognizing means for signal processing the detector signal so as to recognize the symbol being read; and control means for controlling, responsive to the detector signal, the first and second light sources and the scanning means; and selector means for selectively coupling the detector signal to either the recognizing means or the control means, the selector being controlled by the control means.

Claim 23

A symbol read device according to claim 22 further comprising a manually operable switch for controlling the control means so as to override a controlling signal from the second filter.

Claim 24

A symbol read device according to claim 22 further comprising means for selectively driving the first and second light source means to emit light at different times and operate the selector means operates in such a fashion that when the first light source is operative, the detector signal is coupled to the recognizing means and when the second light source means is operative, the detector signal is coupled to the control means.

Claim 25

A symbol read device comprising: a laser beam source for emitting a laser beam; means for pulse driving the laser beam source at a first frequency; means for scanning the laser beam across a symbol surface having a symbol thereon to be read; detector means for receiving light reflected from the symbol surface and generating a detector signal indicative thereof; filter means, having a pass band including the first frequency, for filtering the detector signal; recognizing means, coupled to an output of the filter means, for signal processing the signal from the filter means and recognizing the symbol being read; scan direction detector means for detecting which of a plurality of scan directions the laser beam is being scanned and providing a signal indicative thereof; beam controller means for controlling the pulse driving means, at least partially in response to the signal from the scan direction detector means; first selector means for selecting whether the symbol read device will operate in a multi-direction scan mode or in a unidirectional scan mode and providing a signal to the beam controller means indicative thereof; and second selector means for controlling scan directions when the symbol read device is being operated in the multi-direction scan mode and providing a signal to the beam controller means indicative thereof.

Claim 26

A symbol read device according to claim 25 wherein the scan direction detector means comprises a plurality of detecting elements positioned so as to be responsive only to predetermined scan lines, such that signals produced by the detecting elements indicate which line is being scanned.

Claim 27

A symbol read device according to claim 25 wherein the scan direction detector means comprises: a magnet fixed to the scanning means; and a plurality of coils positioned such that electrical signals are induced in individual coils based on the position of the magnet, the signals from the coils providing an indication of which line is being scanned.

Claim 28

A symbol read device comprising: a laser beam source for emitting a laser beam; means for scanning the laser beam across a symbol surface having a symbol thereon to be read; detector means for receiving light reflected from the symbol surface and generating a detector signal indicative thereof; automatic gain control (AGC) circuit means for amplifying, with variable gain, the detector signal; recognizing means, coupled so as to receive an output of the AGC circuit means, and signal processing the signal therefrom so as to recognize the symbol being read; scan direction detector means for detecting which of a plurality of scan directions the laser beam is being scanned and providing a signal indicative thereof; beam controller means for controlling the pulse driving means, at least partially in response to the signal from the scan direction detector means; first selector means for selecting whether the symbol read device will operate in a multi-direction scan mode or in a unidirectional scan mode and providing a signal to the beam controller means indicative thereof; and second selector means for controlling scan directions when the symbol read device is being operated in the multi-direction scan mode and providing a signal to the beam controller means indicative thereof.

Claim 29

A symbol read device according to claim 28 wherein the scan direction detector means comprises a plurality of detecting elements positioned so as to be responsive only to predetermined san lines, such that signals produced by the detecting elements indicate which line is being scanned.

Claim 30

A symbol read device according to claim 28 wherein the scan direction detector means comprises: a magnet fixed to the scanning means; and a plurality of coils positioned such that electrical signals are induced in individual coils based on the position of the magnet, the signals from the coils providing an indication of which line is being scanned.

Claim 31

A symbol read device according to claim 28 wherein the AGC circuit means comprises: a variable gain amplifier (VGA) having an input coupled to receive the detector signal; an integrator coupled to an output of the VGA for integrating its output; and a sample and hold circuit coupled to an output of the integrator for sampling and holding an output value thereof, the sample and hold circuit feeding back a value to the VGA for controlling its gain.

Claim 32

A symbol read device according to claim 28 wherein the AGC circuit means comprises: a variable gain amplifier (VGA) having an input coupled to receive the detector signal; an integrator coupled to an output of the VGA for integrating its output; and a plurality of sample and hold circuits selectively coupled to an output of the integrator, each sample and hold circuit corresponding to a particular scan line, the sample and hold circuits sampling and holding an output value of the integrator and selectively feeding back a value to the VGA for controlling its gain.