CN203386219U

CN203386219U - System for reading code symbols in scanning field

Info

Publication number: CN203386219U
Application number: CN201320409911.0U
Authority: CN
Inventors: R·H·布拉迪; S·科拉维托; D·老维尔斯; 滕芝鹏; M·L·迪克松
Original assignee: Metrologic Instruments Inc
Current assignee: Metrologic Instruments Inc
Priority date: 2012-05-21
Filing date: 2013-05-20
Publication date: 2014-01-08
Anticipated expiration: 2023-05-20

Abstract

The utility model relates to a method and a system for reading bar code symbols by using a handheld laser scanning bar code symbol reading system. The system can be used to support the improved control of the length and the strength characteristic of a laser scanning line projected onto a scanned target at any time in a manner according to the detected position, distance or range of the scanned target in a scanning field of the system in the system operating process. The system comprises a laser scanning module which is used to project a laser scanning beam through a light transmission window and stride across the laser scanning field in which the target is located, and at the same time, the laser scanning beam is extinguished according to the estimated distance or a laser source blanking function which is determined by data representative of the laser scanning beam in the laser scanning period.

Description

A kind of system for the code sign that reads scanning field

The priority application cross reference

That the application requires to submit on May 21st, 2012, title is numbered 61/632 for " with the lasing light emitter blanking, controlling to provide the laser scanning code sign reading system to the improvement control of the length of the laser scanning line from its projection and strength characteristics ", the rights and interests of 426 U.S. Patent application, it is incorporated to this paper by integral body by reference.

Technical field

The disclosure relates to a kind of improved method and apparatus, for read in the bar code symbol of various scanning circumstances by laser scanning bundle technology.

Background technology

Typically, single line laser scan bar code symbol reading system has the nominal scanning angle, and its control projects the width (being length) of the sweep trace on target surface.In the great majority design, this scanning angle is fixed, and in most of the cases, the length of scanning line is enough at given scanning distance place.

Yet, the application of the scanning of existence such as barcode menus and long-range scanning, wherein aspect the length of controlling laser scanning line and strength characteristics, need higher dirigibility, in order to avoid the beam energy characteristic of not expecting occurred at the terminal position place of laser scanning line, this laser scanning bundle slows down, stops fully and then accelerates in the opposite direction during every half complete laser beam flying cycle there.

A kind of improved laser scanning code sign reading system need to be provided in this area strongly, and it has controls the improvement level of the length of laser scanning line and strength characteristics, avoids deficiency and the defect of the method and apparatus of prior art simultaneously.

Summary of the invention

A main target of the present disclosure is to provide a kind of improved laser scanning code sign reading system, and it has controls the improvement level of the length of laser scanning line and strength characteristics, and there is no deficiency and the defect of prior-art devices and method.

Another target is to provide a kind of laser scanning code sign reading system, when it arrives its least significant end position when laser beam along laser scanning line,, laser beam is decelerated to and stops and while then accelerating in the opposite direction there, control length and the strength characteristics of laser scanning line by its laser beam sources of automatically stopping using, to improve from laser safety situation and/or the aesthetic characteristic of the laser scanning line of laser scanning code sign reading system projection.

Another target is to provide a kind of laser scanning code sign reading system, it is only when laser beam arrives its least significant end position along laser scanning line, control length and the strength characteristics of laser scanning line by its laser beam sources of automatically stopping using, to eliminate whereby any Strength Changes occurred in the end of laser scanning line in the deceleration of the end of laser scanning line/stop/accelerated motion due to the laser scanning bundle.

Another target is to provide such laser scanning code sign reading system, wherein in response to the scanning generated by the SOS/EOS detecting device, start (SOS) and the end of scan (EOS) signal, the length of laser scanning line and strength characteristics are controlled by the programming firmware, and and if only if laser beam is stopped using while along laser scanning line, arriving its least significant end position automatically laser beam sources, wherein due to laser beam in the deceleration at the terminal position place of laser scanning line/stop/acceleration charactersitic, the laser beam velocity variations is significant.

Another target of the present invention is to provide such laser scanning code sign reading system, wherein, by controlling the running time of visible laser diode source, this system can utilize the laser scanning line that is projected to the length-specific on the target that will be scanned effectively to scan target during each laser scanning cycle.

Another target of the present invention is to provide such laser scanning code sign reading system, wherein this visible laser diode source is deactivated during each laser scanning cycle, in order to do not generate laser beam in the end that sweeps angle, thereby eliminated the laser beam bright spot of not expecting produced when the laser scanning bundle changes its beam direction at the place, end of each scan period.

Another target is to provide a kind of hand-holdable long distance laser scan code symbol reading system, it adopts visible laser diode (VLD) and beam moulding/focusing optics, visible laser bundle for generation of scanning target on the remote part of the scanning field in system, wherein when laser beam arrives its terminal position along laser scanning line, this visible laser bundle is stopped using automatically, to limit whereby the length of laser scanning line.

Another target is to provide a kind of hand-holdable long distance laser scan code symbol reading system, it adopts visible laser diode (VLD) and beam moulding/focusing optics, visible laser bundle for generation of scanning target on the remote part of the scanning field in system, wherein the scope of this target is determined by the intensity/amplitude of return laser beam, and the length of laser scanning line is controlled by the visible laser diode of automatically stopping using within one period duration, the form that this duration is activated by range data contrast scans angle lasing light emitter and the range data of obtaining are determined.

Another target is to provide a kind of hand-holdable pair of laser scanning bar code symbol reading system of automatic triggering, this system has ability and comes during system operated, to be scanned the mode of the detected position of target in the visual field that depends on system, control is from length and the strength characteristics of the laser scanning line of the projection of one of two lasing light emitters automatically at any time.

Another target is to provide hand-holdable pair of laser scanning code sign reading system of so automatic triggering, it adopts the first visible laser diode (VLD) and first beam moulding/focusing optics, for generation of the first visible laser bundle, it is suitable for scanning target on first (far) range section of the scanning field of system, and second visible laser diode (VLD) and second beam moulding/focusing optics, for generation of the second visible laser bundle, it is suitable for scanning target on second (closely) range section of the scanning field of system, and wherein when this first laser beam arrives its terminal position along laser scanning line, this first visible laser bundle is stopped using automatically, with the length (being width) that limits whereby (shortening) laser scanning line, and prevent from generating slow or static laser beam during position endways.

Another target is to provide a kind of hand-holdable pair of laser scanning code sign reading system, wherein the optical alignment of each VLD and power input are controlled, and public laser scanning mechanism is used to make two laser scanning Shu Jinhang scannings, but with different sweep speeds, make first (closely) scope laser beam with than second (far) scope laser beam faster speed scanned, and this sweep speed is balanced, for example, to allow identical decoding electronic installation (to be used by two laser scanning bundles, if closely subsystem is designed to the peak signal frequency of the 100KHz under certain sweep speed, the sweep speed for remote subsystem will be selected such that the peak signal frequency is similarly 100KHz).

Further target of the present disclosure will be hereinafter and it is become to more apparent in appended claim.

The accompanying drawing explanation

For this target of comprehend, the following detailed description of illustrative embodiment should read in conjunction with the accompanying drawings, wherein:

The skeleton view of the first illustrative embodiment of the hand-holdable laser scanning bar code symbol reading system that Fig. 1 is manual triggers, this system has ability and comes in system operating period, to depend on the mode of program parameters and/or operating conditions, automatically control length and the strength characteristics of the laser scanning line projected at any time;

Fig. 2 is for describing the schematic block diagram of the Major Systems parts of the laser scanning bar code symbol reading system of illustrated manual triggers in Fig. 1;

Fig. 3 maintains during laser scanning operation for the decoding processor by the system of Fig. 1, and each laser scanning direction is kept the schematically showing of scan-line data impact damper of digital scanning line data during each laser scanning cycle;

The diagram of VLD in the laser scanning bar code symbol reading system that Fig. 4 is Fig. 1, wherein by three different laser scanning Shu Shengcheng and be projected on the target at three different scannings distance or scope place, make the terminal position (in the intensity distribution of scanning beam) of each laser scanning line on the target that is projected to the arbitrary scan distance substantially there is no bright spot or focus, this bright spot or focus typically by during each scan period the laser beam of each sweep trace end stop and reversion on the direction of propagation causes;

Fig. 5 has set forth the process flow diagram of describing laser scanning bar code symbol reading system performed key step during each laser scanning cycle of Fig. 1, and where the scanning field that itself and target are positioned at system has nothing to do;

Fig. 6 is the skeleton view of the second illustrative embodiment of the automatic hand-holdable pair of laser scanning bar code symbol reading system triggered, this system has ability and comes in system operating period, to be scanned the mode of the detected position of target in the visual field that depends on system, control is from length and the strength characteristics of the laser scanning line of the projection of one of two laser source automatically at any time.

Fig. 7 is for describing the schematic block diagram of the Major Systems parts of two laser scanning bar code symbol reading systems of illustrated automatic triggering in Fig. 6;

Fig. 8 maintains during laser scanning operation for the decoding processor by the system of Fig. 6, and each laser scanning direction is kept the schematically showing of scan-line data impact damper of digital scanning line data line during each laser scanning cycle;

In the laser scanning bar code symbol reading system that Fig. 9 is Fig. 6, two VLD's schematically shows, wherein by three different laser scanning Shu Shengcheng and be projected on the target at three different scannings distance or scope place, make the laser scanning line of relative constant length be projected on target, and irrelevant with scanning distance;

The process flow diagram of the key step that the laser scanning bar code symbol reading system that Figure 10 A and 10B are description Figure 11 is carried out during each laser scanning cycle, where the scanning field that itself and target are positioned at system has nothing to do;

The skeleton view of the 3rd illustrative embodiment of the hand-holdable laser scanning bar code symbol reading system that Figure 11 is manual triggers, this system has ability and comes in system operating period, with the program parameters that depends in the visual field that comprises system the scope of determining/estimating that is scanned target and/or the mode of operating conditions, automatically control length and the strength characteristics of the laser scanning line projected at any time;

Figure 12 is for describing the schematic block diagram of the Major Systems parts of the laser scanning bar code symbol reading system of illustrated manual triggers in Figure 11;

Figure 13 maintains during laser scanning operation for the decoding processor by the system of Figure 11, and each laser scanning direction is kept the schematically showing of scan-line data impact damper of digital scanning line data during each laser scanning cycle;

VLD in the laser scanning bar code symbol reading system that Figure 14 is Figure 11 schematically shows, the laser beam of stopping using of the different time during the scan period by the distance of the targeted scans based on estimating wherein, by three different laser scanning Shu Shengcheng and be projected on the target at three different scannings distance or scope place, make the laser scanning line of relative constant length be projected on target, and irrelevant with scanning distance; And

Figure 15 has set forth the process flow diagram of the key step that the laser scanning bar code symbol reading system of describing Figure 11 carries out during each laser scanning cycle, and where the scanning field that its and target are positioned at system has nothing to do.

Embodiment

With reference to the figure in accompanying drawing, the illustrative embodiment of two laser scanning bar code symbol reading systems will be described in more detail, and wherein similar elements will be indicated with identical reference number.

adopt the hand-holdable laser scanning code sign reading system of the manual triggers of programming lasing light emitter inactive (being blanking) control

Referring now to Fig. 1 to 5 in detail, the first illustrative embodiment of the hand-holdable laser scanning bar code symbol reading system 1 of manual triggers will be described.As hereinafter described in the first illustrative embodiment, use programming lasing light emitter inactive (being blanking), the end portion that makes each laser scanning line on the target that is projected to the arbitrary scan distance does not have bright spot or focus substantially along the intensity distribution of scanning beam, this bright spot or focus typically by during each scan period the end of each sweep trace laser beam stop and the direction of propagation on reversion cause.Yet should be understood that, this programming lasing light emitter inactive (being blanking) also can be used to realize during each laser scanning cycle the length of scanning line and the strength control of other kind in laser scanning system.

As shown in figs. 1 and 2, the laser scanning bar code symbol reader 100 of manual triggers has operating distance, and the assembly of parts, and it comprises: hand-holdable shell 102, and it has the shank of head and supporting head part; Light-transmissive window 103, its head with shell 102 is mutually integrated; The trigger switch 104 of manual activation, its shank with shell is mutually integrated, for generating trigger event signal, activates the laser scanning module 105 with laser scanning field 115; Laser scanning module 105, it is for the control signal in response to being generated by system controller 150, make the visible laser bundle leap laser scanning field for example, generated by lasing light emitter 112 (VLD or IR LD) carry out multiple scanning, this lasing light emitter 112 has optical device and focuses on the laser scanning bundle in the laser scanning field with generation; Wherein this laser scanning module 105 also comprises laser drive circuit 151, and it is for from system controller 150 reception control signals, and in response to this, generate and transmission laser (diode) driving current signal to lasing light emitter 112A; Scanning beginning/the end of scan (SOS/EOS) detecting device 109, it is for the timing signal of the end that generates the indication beginning that sweeps of laser beam and each laser beam and sweep, and sends these SOS/EOS timing signals to system controller 150 and decoding processor 108; Light is collected optical device 106, it is for collecting the light that is scanned target institute reflect/scatter from scanning field, and photodetector, it generates the analog scanning data-signal corresponding to described detected light intensity for detection of collected light intensity and during scan operation; Analog scanning data signal processor/digital quantizer 107, it is for the treatment of the analog scanning data-signal, and convert handled analog scanning data-signal to the digital scanning data-signal, then it be converted into numeric word (digital word), and this numeric word means the relative width in bar shaped and the blank code sign structure scanning and is transferred to decoding processor 108 by circuit 142; One group of scan-line data impact damper 160, it is for during each scan period, be buffered in each complete scan-line data of collecting during complete the sweeping of the laser scanning bundle of crossing over the laser scanning field (for example two scan-line data impact dampers, for being buffered in the data of collecting during direction of scanning); Programming decoding processor 108, it processes the digitalized data be stored in described scan-line data impact damper 160 for decoding, and generates the symbol character data that means each bar code symbol of being scanned by the laser scanning bundle; I/O (I/O) communication interface modules 140, it is for being docked with main-machine communication system 154, and by the wired or wireless communication link 155 supported by symbol reader and host computer system 154 to its transmission symbol character data; And system controller 150, its for generating necessary control signal in order to control the operation in hand-holdable laser scanning bar code symbol reading system, wherein this system controller 150 comprises VLD blanking control module 150A, it is for programming or inactive (being blanking) the function B (t) of suitable lasing light emitter (VLD) is set, for be used under the particular case during each laser scanning cycle the lasing light emitter 112A that stops using by laser drive circuit 151, in order to extinguish (closing) this laser scanning bundle according to lasing light emitter blanking function B (t) in this case during the laser scanning cycle.

Especially, VLD blanking function B (t) can may mode specify according to a plurality of, includes but not limited to: (i) for symmetrical VLD blanking function B (t), by specifying a percentage of time (P who measures from the center of each scan period _a, P _a), indication has total duration T _sCeach scan period during VLD how long should be deactivated; And (ii) for asymmetric VLD blanking function B (t), two different percentage of time (P that specify the eccentric position from departing from each scan period to measure _a, P _b), indication has total duration T _sCeach scan period during VLD how long should be deactivated.The total duration T of each scan period _sCcan determine according to the sweep velocity of scan components, this sweep velocity will basically be maintained constant during scan operation.

As shown in Figure 2, laser scanning module 105 comprises a plurality of subassemblies, has the laser scanning assembly 110 of solenoid 128 and rotatable scanning element (for example catoptron) 134 that is:, and it supports lightweight reflecting element (for example catoptron) 134A; Coil driver 111, for generating the solenoid 128 of electric drive signal with driving laser scan components 110; And laser beam sources 112A, for generation of visible laser bundle 113A; And beam deflecting mirror 114, for laser beam 113A is deflected to the incident beam 114A towards the reflection mirror component of laser scanning assembly 110, it is crossed over laser scanning field and may come across in system operating period the laser beam 114B that bar code symbol 16 wherein sweeps deflection simultaneously.

As shown in Figure 2, laser scanning module 105 typically is installed in optical bench, P.e.c. (PC) plate or also installs on other surface of laser scanning assembly, and comprise coil support part 110, for near supporting electric magnetic coil 128 (permanent magnet 135), and it is driven by scanner drive circuit 111, make it in scan components operating period, on the opposite pole of permanent magnet 135, generate magnetic force.Suppose between the attribute of permanent magnet 135 and permanent magnet 135 and solenoid 128 apart from substantially constant, the power on permanent magnet 135 and the scanning element that is associated thereof of putting on provides the electric drive current I to solenoid 128 during for scan operation _dC(t) function.Usually, the drive current I produced by scanner drive circuit 111 _dC(t) level is larger, and the power put on permanent magnet 135 and the scanning element that is associated thereof is just larger.Therefore, the scanning of scan module 105 sweeps angle α (t) and can directly by control under the control at controller 150, by scanner drive circuit 111, provide the drive current I to coil 128 _dC(t) level is controlled, as shown in Figure 2.In the disclosure, lock this drive current I _dC(t) will be to control the method for optimizing that (keeping constant) sweeps angle α (t) during scan operation.

Usually, system 100 is supported the operator scheme of manual triggers, and bar code symbol read method described below.

In response to the manual activation of trigger switch 104, laser scanning module 105 generates the laser scanning bundle and it is projected and cross over the laser scanning field 115 of hand-holdable housing exterior by light-transmissive window 103, for the target to scanning field, is scanned.This laser scanning bundle is generated in response to the control signal generated by system controller 150 by lasing light emitter 112B.During laser scanning operation, the system control parameters (SCP) of VLD blanking control module 150A based on arranging at any time, be provided for the suitable VLD blanking function B (t) of laser drive circuit 151.VLD blanking function B (t) during each laser scanning cycle, specify VLD 112A will be when by laser drive circuit 151 automatically stop using (deenergizing), therefore and specify visible laser will when not be produced and not be transmitted to scanning field, electromagnetic scanning assembly 110 is attempted crossing over the laser scanning field during the laser blanking interval of appointment and is swept the laser scanning bundle along any target of its scanning pattern simultaneously.Scanning element (being mechanism) 134 in the laser scanning field so that during scan operation, by controller 150, set constant scanning sweeps angle α (t) and crosses over target and make this laser beam multiple scanning.Then, light is collected the light of the scan code symbol institute reflect/scatter on the target of optical device 106 collections from scanning field, and photodetector (106) detects collected light intensity (being photon energy) automatically, and generate the analog scanning data-signal corresponding to the light intensity detected during scan operation.

For realizing VLD blanking function B (t), the scanning that the firmware in system controller 150 detects from SOS/EOS detecting device 109 starts (SOS) signal, and it uses the beginning of each new sweep trace of signal designation.Firmware in programmable controller 150 can also the sweep velocity based on laser scanning mechanism calculate the time proximity be associated with the complete scan line.In illustrative embodiment, the approximate duration T of complete scan line _sLbe 10 milliseconds, but can be from embodiment to embodiment and different.Based on this complete scan line duration T _sLfirmware is searched the VLD blanking function B (t) of appointment, this VLD blanking function B (t) is specified by the system control parameters (SCP) of in-system programming, and according to this VLD blanking function, determine required VLD blanking number percent, and use these numerals (figure) to control VLD driving circuit 151, VLD deenergized and energize with during sweeping in scanning, thereby producing the laser beam blanking effect of expectation along the laser scanning line projected.For example, if blanking number percent is 10, VLD driving circuit 151 will make the scanning of 10 milliseconds of VLD blankings sweep 10% of the duration, and its scanning that is total up to 1 millisecond sweeps the duration.Then controller firmware (being module 150A) will make VLD sweep blanking in first 0.5 millisecond of the duration and last 0.5 millisecond in the scanning of laser scanning bundle, produce the laser beam blanking effect of expectation with the laser scanning line along being projected.

Analog scanning data signal processor/digital quantizer 107 treatment of simulated scan-data signals, and convert the scan-data signal of handled simulation to digitized data signal.Digitized data signal are processed in the decoding of programming decoding processor 108, and generate the symbol character data that means each bar code symbol of being scanned by the laser scanning bundle.The bar code symbol of decoding can be the bar code symbol of programming type or Menu Type, or the bar code symbol of general data coding, and it is not intended to any programming or the special operational carried out or trip bar code sign scanner is interior.

Then the symbol character data corresponding with the bar code that is read (i.e. decoding) by demoder 108 be transferred to host computer system 154 by I/O communication interface 140, and this I/O communication interface 140 can be supported wired and/or wireless communication link 155 well known in the art.During target detection and laser scanning operation, system controller 150 generates necessary control signal, for controlling the operation in hand-holdable laser scanning bar code symbol reading system.

With reference to Fig. 5, the method for the operation in reading bar code symbols and control laser scanning bar code reader 100 has been described in more detail.

As indicated in Fig. 5, start from starting frame A place by the process of 150 layouts of system controller, wherein all system units are activated, except laser instrument and scanning motor (being solenoid).Then the frame B place in Fig. 5, system controller is determined and is triggered or whether the activation event (be trigger switch 104 be not operated the person manually press) occurs.

If the frame B place in Fig. 5, trigger event is detected, system controller advances to frame C, and (i) utilize enough electric currents to activate laser diode and scanner drive circuit 111, sweep angle and for the VLD blanking function B (t) of scanning process with the scanning that generates appointment, and (ii) then start timeout period timer T1.

Frame D place in Fig. 5, analog scanning data signal processor/digital quantizer ASIC 107 processes simulation and/or the digital scanning data-signal returned.

Frame E place in Fig. 5, the system controller order, in data buffer 160, is buffered in the whole scannings that arrange during the scan period and sweeps angle and the upper complete scan line data collected for direction of scanning of VLD blanking function B (t).Scan-data from each direction of scanning is buffered in different scan-line data impact dampers.

Frame F place in Fig. 5, system controller determines that decoding processor 108 is whether based on collecting and be buffered in sweep trace in scan-data impact damper 160 and the decoding bar code sign.

If the frame F place in Fig. 5, bar code symbol is not yet in the scan-line data of buffering decoded (that is, reading), and system controller advances to frame G and determines whether to reach timeout period T1.If also do not reach timeout period, system controller is back to frame D, and the processing scan data signal.Thereafter, system controller advances to frame E, and attempts collecting in remaining time period T1 and the decoding scan-data.If reached timeout period at frame G place, system controller advances to frame GH, sends the decoding failure notification to host computer system, and then at frame I place, stop using this lasing light emitter and scanning motor, and then turns back to frame B, as shown in Figure 5.

Utilize the novel control procedure described in Fig. 5, this bar code symbol reader has ability and dynamically adjusts visible laser scanning beam during each laser scanning cycle from effectively emission or time of not launching of VLD 112A.Especially, bar code symbol reader with its VLD blanking function of realizing has guaranteed to be projected in each sweep trace end the intensity of beam be scanned on target automatically, during each scan period, will never when laser beam stops its motion, cross bright or produce focus, and will never change direction in the end of each sweep trace.

the hand-holdable laser scanning bar code symbol reading system of the automatic triggering that the lasing light emitter inactive (being blanking) that the employing scope is relevant is controlled

Referring now to Fig. 6 to 10B in detail, the second illustrative embodiment of the hand-holdable laser scanning bar code symbol reading system 500 automatically triggered will be described.As following, will in the second illustrative embodiment, describe, system 500 is interior has used lasing light emitter that scope is relevant stop using (being blanking), be projected to the length of each laser scanning line on the target of arbitrary scan distance with control, make on the operating distance of two VLD laser scanning systems this length of scanning line substantially constant.Yet it being understood that lasing light emitter that this scope is relevant stop using (being blanking) also can be used to realize the length of scanning line and the strength control of other kind in each laser scanning cycle in laser scanning system.

As shown in Fig. 6 and 7, the laser scanning bar code symbol reader 500 automatically triggered has operating distance, and the assembly of parts, and it comprises: hand-holdable shell 102, and it has the shank of head and supporting head part, light-transmissive window 103, its head with shell 102 is mutually integrated, (or LED-based) target detection based on IR and scope subsystem 219, it generates the light beam based on IR or LED in the working range of laser scanning field, as shown in Figure 6, appearance for automatic detection laser scanning field target, when target is automatically detected in scanning field, send a signal to controller 150, if and the detected nearly part that is positioned at scanning field of this target, system controller 150 activates near field VLD 112A, if or this target is detected the distal part that is positioned at scanning field, system controller 150 activation far field VLD 112B, laser scanning module 105, it makes visible laser bundle leap laser scanning field carry out multiple scanning for the control signal in response to being generated by system controller 150, this visible laser bundle is generated by following: (i) have near-field optics focuses on the nearly part of laser scanning field the first lasing light emitter 112A (for example VLD or IRLD) of laser scanning bundle 113A with generation, or (ii) have far-field optics focuses on the distal part of laser scanning field the second lasing light emitter 112B (for example VLD or IR LD) of laser scanning bundle 113B with generation, wherein this laser scanning module 105 also comprises laser drive circuit 151, for receiving the control signal from system controller 150, and in response to this, the distance that the institute based on being scanned target in scanning field detects or estimates or scope R (t) and generates and carry different laser (VLD) driving current signal extremely closely VLD 112A or VLD 112B far away, scanning beginnings/the end of scan (SOS/EOS) detecting device 109, it is for generating the beginning of indicating each laser beam to sweep and the timing signal stopped, and sends these SOS/EOS timing signals to system controller 150 and decoding processor 108, light is collected optical device 106, it is for collecting the light that is scanned target institute reflect/scatter from scanning field, and photodetector, it generates the analog scanning data-signal corresponding to detected light intensity for detection of collected light intensity and during scan operation, analog scanning data signal processor/digital quantizer 107, it is for the treatment of the analog scanning data-signal, and convert handled analog scanning data-signal to the digital scanning digital signal, then it be converted into numeric word, and this numeric word means bar shaped and blank relative width in the code sign structure of scanning, one group of scan-line data impact damper 160, cross over collected each complete scan-line data (for example, for two direction of scanning) during complete the sweeping of laser scanning field for being buffered in laser scanning bundle during each scan period, programming decoding processor 108, it processes the digitalized data be stored in described scan-line data impact damper 160 for decoding, and generates the symbol character data that means each bar code symbol of being scanned by the laser scanning bundle, scan-data signal strength detection module 143, it preferably is implemented in scan-data processor/digital quantizer 143, for simulation (or numeral) the scan-data signal that (i) processing is returned continuously, (ii) detect and analyze the intensity (being amplitude) of laser return signal, (iii) determine that (for example estimating) is scanned scope or the distance R (t) of target with respect to scanning window, and then (iv) for example, transfers to the VLD blanking control module 150A in controller 150 by scope indication (estimating) signal form of digital data value (with), make it able to programme or suitable lasing light emitter (VLD) (being blanking) the function B (t) that stops using is set, be used for for laser drive circuit 151, with stop using under the particular case during each laser scanning cycle lasing light emitter 112A or 112B, in order to extinguish (closing) this laser scanning bundle according to lasing light emitter blanking function B (t) in this case during the laser scanning cycle, I/O (I/O) communication interface modules 140, it is for being docked with main-machine communication system 154, and by the wired or wireless communication link 155 supported by symbol reader and host computer system 154 to its transmission symbol character data, and system controller 150, its for generating necessary control signal in order to control the operation in hand-holdable laser scanning bar code symbol reading system.

Preferably, (or LED-based) target detection subsystem 219 based on IR is installed in the place ahead of its light-transmissive window 103, make its IR optical transmitting set and the IR optical receiver parts (or VLD optical transmitting set and receiver parts) of subsystem 219 there is the unscreened target visual field in the laser scanning field of system, as shown in fig. 1.And, target exists detection module 219 IR (or visible) signal that has continuous low-intensity output level or have a more high strength output level of pulse can be transferred in scanning field 115, this signal can be used under certain conditions, to increase the target detection scope of system.In alternative embodiment, IR optical transmitting set and IR optical receiver parts can be implemented as respectively visible ray well known in the art (for example ruddiness) transmitter and visible ray (for example ruddiness) receiver parts.Typically, the target detection light beam is modulated and synchronous detection, as United States Patent (USP) 5,340, instructs in 971, and it is incorporated to this paper by reference.

Especially, VLD blanking function B (t) can may mode specify according to a plurality of, includes but not limited to: (i) for symmetrical VLD blanking function B (t), by specifying a percentage of time (P who measures from the center of each scan period _a, P _a), indication has total duration T _sCeach scan period during VLD how long should be deactivated; And (ii) for asymmetric VLD blanking function B (t), by specifying two different percentage of time (P that measure from the eccentric position of each scan period _a, P _b), indication has total duration T _sCeach scan period during VLD how long should be deactivated.The total duration T of each scan period _sCcan determine according to the sweep velocity of scan components, this sweep velocity will maintain substantially constant during scan operation.

As shown in Figure 7, laser scanning module 105 comprises a plurality of subassemblies, that is: laser scanning assembly 110, has solenoid 128 and rotatable scanning element (for example catoptron) 134, and it supports lightweight reflecting element (for example catoptron) 134A; Coil driver 111, for generating the solenoid 128 of electric drive signal with driving laser scan components 110; And laser beam sources (, nearly VLD) 112A, for generation of the visible laser bundle 113A in the nearly part that focuses on scanning field, and laser beam sources is (, VLD far away) 112B, for generation of the visible laser bundle 113B in the distal part that focuses on the laser scanning field; And beam-deflecting mirror 114, for laser beam 113A or laser beam 113B are deflected to the incident beam 114A towards the reflection mirror component of laser scanning assembly 110, it was crossed over the laser scanning field and may appear at the laser beam 114B that bar code symbol 16 wherein sweeps deflection simultaneously in system operating period.

Laser scanning module 105 typically is installed in optical bench, P.e.c. (PC) plate or also installs on other surface of laser scanning assembly, and comprise the coil support part 110 near supporting electric magnetic coil 128 (permanent magnet 135), and it is driven by scanner drive circuit 111, make it in scan components operating period, generate magnetic force on the opposite pole of permanent magnet 135, make reflection mirror component 134 around its turning axle vibration.Suppose between the attribute of permanent magnet 135 and permanent magnet 135 and solenoid 128 apart from substantially constant, the power on permanent magnet 135 and associated scanning element thereof of putting on provides to the function of the electric drive current of solenoid 128 during for scan operation.Usually, the drive current I produced by scanner drive circuit 111 _dC(t) level is larger, and the power put on permanent magnet 135 and associated scanning element thereof is larger.Therefore, the scanning of scan module 105 sweeps angle α (t) and can, directly by under the control of turntable driving current control module 150A, control and provide the drive current I to solenoid 128 by scan drive circuit 111 _dC(t) level is controlled, as shown in Figure 7.Lock this drive current I _dC(t) will be that gated sweep sweeps the constant method for optimizing of angle α (t) during scan operation.

Preferably, intensity detection module 143 is implemented in scan-data processor/digital quantizer 143, this scan-data processor/digital quantizer 143 can be implemented as asic chip, supports the circuit of analog-and digital-two types, and this circuit is carried out function and the operation wherein carried out.The function of intensity detection module 143 is many-sided: (i) process constantly simulation (or numeral) the scan-data signal returned, and the intensity of determination and analysis laser return signal (being amplitude); (ii) determine that (for example estimating) is scanned scope or the distance of target with respect to scanning window during each measurement period; And (iii) the range/distance indicator signal form of digital data value (for example with) is transferred to controller 150, for according to be scanned target measured, detect or the distance or the scope R (t) that estimate arrange suitable VLD blanking function B (t), with for VLD driving circuit 151.

During each measurement period, by carrying out relative signal to noise ratio (S/N ratio) (SNR), measure, be scanned target and be determined (for example estimating) with respect to the scope of scanning window or distance, wherein minimum SNR value can be assumed that in the working range (with respect to scanning window) with system that possible scanning distance farthest is corresponding, and the highest SNR value can be assumed that possible scanning distance the shortest in the working range with system is corresponding.Especially, module 143 can comprise the form of storage pre-calibration sweep limit contrast SNR value, and it can be used for determining of this range/distance R (t).And, during code density can be calculated the scope estimation procedure to the quadratic effect of the intensity of reflection (optics) the scan-data signal that detects in the photodetector place.In such an embodiment, module 143 also can be carried out estimated code density by the transformation in analysis mode scan-data signal, and then module 143 can be used as different code density scopes creates, the form that comprises pre-calibration sweep limit contrast SNR value.In situation about being measured by the code density scope of module 143 given estimations and SNR, these forms can be used to estimate to be scanned target zone.

Usually, system 500 is supported automatic trigger action pattern, and the method that reads of bar code symbol, as described below.

In response to the automatic detection of target in scanning field, laser scanning module 105 generates the laser scanning bundle and it is projected by light-transmissive window 103, and crosses over the laser scanning field 115 of hand-holdable housing exterior, for scanning the target of this scanning field.Detected where in scanning field according to target, this laser scanning bundle is generated by lasing light emitter 112A or lasing light emitter 112B in response to the control signal generated by system controller 150.Scanning element (being mechanism) 134 sweeps the target of crossing in the laser scanning field at angle with the constant scanning being arranged by controller 150 in the duration of scanning process and makes this laser beam 113A or 113B multiple scanning.Then, light is collected the light that is scanned code sign institute reflect/scatter on the target of optical device 106 collections from scanning field, and photodetector (106) detects collected light intensity (being photon energy) automatically, and generate the analog scanning data-signal corresponding to the light intensity detected during scan operation.In analog scanning data signal processor/digital quantizer 107, this intensity detection module 143 is carried out following functions: (i) process constantly simulation (or numeral) the scan-data signal returned; (ii) detect and analyze the intensity (being amplitude) of laser return signal; (iii) determine that (for example estimating) is scanned scope or the distance of target with respect to scanning window during each measurement period; And (iv) the range/distance indicator signal form of digital data value (for example with) is transferred to controller 150, be provided for the suitable VLD blanking function B (t) of VLD driving circuit 151 for the scanning distance R (t) based on detected at any time.VLD blanking function B (t) during each laser scanning cycle, specify VLD 112A will be when by laser drive circuit 151 automatically stop using (deenergizing), therefore and determine when visible laser will not be produced and not be transmitted in scanning field, electromagnetic scanning assembly 110 is attempted crossing over the laser scanning field during the laser blanking interval of appointment and is swept the laser scanning bundle along any target of its scanning pattern simultaneously.

For realizing VLD blanking function B (t), the scanning that the firmware in system controller 150 detects from SOS/EOS detecting device 109 starts (SOS) signal, and it uses the beginning of each new sweep trace of signal designation.Firmware in programmable controller 150 can also the sweep velocity based on laser scanning mechanism calculate the time proximity be associated with the complete scan line.In illustrative embodiment, the approximate duration T of complete scan line _sLbe 10 milliseconds, but can be from embodiment to embodiment and different.Based on this complete scan line duration T _sLwith the scope R that is scanned target (t), firmware is searched the VLD blanking function B (t) of appointment, it is specified by the scope R (t) estimated, and according to this VLD blanking function, determine required VLD blanking number percent, and control VLD driving circuit 151 by these numerals, with during sweeping in scanning, VLD is deenergized and energizes, thereby produce along the expectation laser beam blanking effect of the laser scanning line projected.For example, if blanking number percent is 10, VLD driving circuit 151 will make the scanning of 10 milliseconds of VLD blankings sweep 10% of the duration, and its scanning that is total up to 1 millisecond sweeps the duration.Then controller firmware will make VLD sweep blanking in first 0.5 millisecond of the duration and last 0.5 millisecond in the scanning of laser scanning bundle, produce the laser beam blanking effect of expectation with the laser scanning line along being projected.

Analog scanning data signal processor/digital quantizer 107 is treatment of simulated scan-data signal also, and converts handled analog scanning data-signal to digitized data signal.Digitized data signal are processed in the decoding of programming decoding processor 108, and generate the symbol character data that means each bar code symbol of being scanned by the laser scanning bundle.Decoded bar code symbol can be the bar code symbol of programming type or Menu Type, or the bar code symbol of general data coding, and it is not intended to any programming or the special operational carried out or trip bar code sign scanner is interior.

As indicated on, the VLD blanking function B (t) for the laser scanning bundle is determined at the scope R (t) that given time is scanned target by scanning field arbitrarily.Scope is measured or is estimated and can determine according at least two kinds of different modes: (i) by processing collected return laser light sweep signal; Or (ii) use the range data by the target detection based on LED or IR/range detection mechanism produces.In the situation that the laser scanning signal that processing is returned, laser signal is converted into electric signal, and it is fed in the module 143 in analog scanning data signal processor/digital quantizer 107.The intensity of handled analog or digital scan-data signal, or signal to noise ratio (S/N ratio) (SNR) calculated, and for estimated to be scanned the distance/scope of bar code symbol by asic chip processor 107.Strong signal or height ratio are usually corresponding to shorter range/distance, and weak signal or low ratio are corresponding to larger range/distance.Then VLD blanking function B (t) can dynamically adjust based on signal intensity or SNR and the predetermined form/algorithm be implemented in asic chip 107.Be below example table, it is provided to the situation of explanation for asymmetric VLD blanking function B (t), the relation between above-mentioned these three parameters.These parameters can be trimmed with for having the scanner of different operating scope.

Especially, the VLD blanking of this Dynamic Definition (the stopping using) function that function B (t) is targeted scans scope R (t), it can and typically change any time during scan operation.Therefore, should be understood that, the duration of the VLD blanking function B (t) of dynamic programming also will change in time, and depend on the determined target zone/distance R of module 143 (t) in analog scanning data processor/digital quantizer asic chip 107, as mentioned above.

Then symbol character data corresponding to the bar code that is read (i.e. decoding) by demoder 108 is transferred to host computer system 154 by I/O communication interface 140, and this I/O communication interface 140 can be supported wired and/or wireless communication link 155 well known in the art.During target detection and laser scanning operation, system controller 150 generates necessary control signal, for controlling the operation in hand-holdable laser scanning bar code symbol reading system.

With reference to Figure 10 A, will the method for reading bar code symbols and the 50 interior operations of control laser scanning bar code reader be described in more detail.

As indicated in Figure 10 A, start from starting frame by the process of 150 layouts of system controller, wherein all system units are activated, except laser instrument and scanning motor (being solenoid).Then the frame A1 place in Figure 10 A, system controller determines whether target is detected in scanning field.If target is detected at frame A1 place, system controller advances to frame A2, and determines that whether detected target is detected in the nearly part of scanning field.If so, at frame B place, system controller (i) utilizes enough electric currents to activate laser diode and scanner drive circuit 111, with the scanning generated for the acquiescence of the nearly part of scanning field, sweeps angle α _o(t), (ii) then start timeout period timer T1, (iii) use near field VLD scanning target, (iv) collection processing scan data are to determine scope or the distance that is scanned target and scanning window, and (v) and then scope R (t) measured or that estimate is arranged to VLD blanking function B (t), and then collect and process the scan-line data from the target at institute sensing range place.The system controller order, in scan-data impact damper 160, is buffered in the whole scannings that arrange during the current scan period and sweeps on angle the complete scan line data collected for direction of scanning.Scan-data from each direction of scanning is buffered in different scan-line data impact dampers.At frame C place, the scan-line data operation decoding algorithm of decoding processor to collecting and cushioning.

At frame D place, system controller determines that decoding processor 108 is whether based on collecting and be buffered in sweep trace in scan-data impact damper 160 and the decoding bar code sign.If at frame D place, bar code symbol is in the scan-line data of buffering decoded (that is, reading), and, at frame E place, system controller transfers to host computer system by symbol character data, and is back to frame A1.If at frame D place, bar code symbol is not yet in the scan-line data of buffering decoded (that is, reading), and at frame F1 place, system controller determines whether to reach timeout period T1 (that is, reached or complete maximum scan threshold value).If also do not reach timeout period, system controller is back to frame B, and the processing scan data signal is determined target zone and upgraded the scan angle of laser scanning bundle, and attempts collecting in remaining time period T1 and the decoding scan-data.If reached timeout period, system controller advances to frame F2, sends the decoding failure notification, and can stop using this lasing light emitter and scanning motor (doing like this if be programmed to), and then is back to frame A1, as directed.

If the frame A2 place in Figure 10 A, detected target is not detected in the nearly part of scanning field, system controller advances to frame G, and controller (i) (again) activation laser diode and scanner drive circuit 111, to generate constant scanning, sweeps angle α _o(t), distal part for scanning field, (ii) start timeout period timer T1, (iii) use far field VLD scanning target, (iv) collection processing scan data are to determine scope or the distance R (t) that is scanned target and scanning window, and (v) scope R (t) measured or that estimate is arranged to VLD blanking function B (t), and collect and process the scan-line data from the target at institute sensing range place.The system controller order, in scan-data impact damper 160, is buffered in the whole scannings that arrange during the current scan period and sweeps on angle the complete scan line data collected for direction of scanning.Scan-data from each direction of scanning is buffered in different scan-line data impact dampers.At frame H place, the scan-line data operation decoding algorithm of decoding processor to collecting and cushioning.

At frame I place, system controller determines that decoding processor 108 is whether based on collecting and be buffered in sweep trace in scan-data impact damper 160 and the decoding bar code sign.If at frame I place, bar code symbol is in the scan-line data of buffering decoded (that is, reading), and, at frame J place, system controller transfers to host computer system by symbol character data, and is back to frame A1.If at frame I place, bar code symbol is not yet in the scan-line data of buffering decoded (that is, reading), and at frame K place, system controller determines whether to reach timeout period T1 (reached or complete maximum scan threshold value).If also do not reach timeout period, system controller is back to frame G, the processing scan data signal, determine target zone and upgrade the VLD blanking function B (t) for detected scanning distance R (t), and attempt collecting in remaining time period T1 and the decoding scan-data.If reached timeout period, system controller advances to frame L, sends the decoding failure notification, and can stop using this lasing light emitter and scanning motor (doing if be programmed like this), and then is back to frame A1, as directed.

Utilize the described novel control procedure of Figure 10 A and 10B, this bar code symbol reader has ability and dynamically adjusts visible laser scanning beam during each laser scanning cycle from effectively emission or time of not launching of VLD 112A or 112B 112A, in order to control and/or maintain during bar code symbol reads process, is projeced into length and the strength characteristics that is scanned the sweep trace on target.In some applications, length of scanning line L _sLcan be maintained substantially constant being scanned on target, and irrelevant with scanning distance R (t).In other embodiments, in the preset limit of the different sensing ranges for scanning distance R (t), length of scanning line L _sLbe maintained substantially constant being scanned on target.In another embodiment, the end of each sweep trace can be truncated, bright spot or focus when eliminating its direction of laser scanning Shu Fanzhuan during scan operation.

the hand-holdable laser scanning code sign reading system of the manual triggers that the lasing light emitter inactive (that is, blanking) that the employing scope is relevant is controlled

Referring now to Figure 11 to 12 in detail, the 3rd illustrative embodiment of the hand-holdable laser scanning bar code symbol reading system 1 of manual triggers will be described.As following, will in the 3rd illustrative embodiment, describe, system 700 is interior has used lasing light emitter that scope is relevant stop using (being blanking), be projected to the length of each laser scanning line on the target of arbitrary scan distance with control, make this length of scanning line substantially constant on the operating distance of single VLD laser scanning system.Yet it being understood that lasing light emitter that this scope is relevant stop using (being blanking) also be used in during inherent each laser scanning cycle of laser scanning system the length of scanning line and the strength control that realizes other kind.

As shown in Figure 11 and 12, the laser scanning bar code symbol reader 700 of manual triggers has operating distance, and the assembly of parts, and it comprises: hand-holdable shell 102, and it has the shank of head and supporting head part, light-transmissive window 103, its head with shell 102 is mutually integrated, the trigger switch 104 of manual activation, its shank with shell is mutually integrated, for generating trigger event signal, activates the laser scanning module 105 with laser scanning field 115, laser scanning module 105, it is for the control signal in response to being generated by system controller 150, make the visible laser bundle leap laser scanning field for example, generated by lasing light emitter 112 (VLD or IR LD) carry out multiple scanning, this lasing light emitter 112 has optical device and focuses on the laser scanning bundle in the laser scanning field with generation, wherein this laser scanning module 105 also comprises laser drive circuit 151, and it is for from system controller 150 reception control signals, and in response to this, generate and transmission laser (diode) driving current signal to lasing light emitter 112A, scanning beginning/the end of scan (SOS/EOS) detecting device 109, it is for the timing signal of the end that generates the indication beginning that sweeps of laser beam and each laser beam and sweep, and sends these SOS/EOS timing signals to system controller 150 and decoding processor 108, light is collected optical device 106, it is for collecting the light that is scanned target institute reflect/scatter from scanning field, and photodetector, it generates the analog scanning data-signal corresponding to described detected light intensity for detection of collected light intensity and during scan operation, analog scanning data signal processor/digital quantizer 107, it is for the treatment of the analog scanning data-signal, and convert handled analog scanning data-signal to the digital scanning data-signal, then it be converted into numeric word, and this numeric word means the relative width in bar shaped and the blank code sign structure scanning and is transferred to decoding processor 108 by circuit 142, scan-data signal strength detection module 143, it preferably is implemented in scan-data processor/digital quantizer 143, for simulation (or numeral) the scan-data signal that (i) processing is returned continuously, (ii) detect and analyze the intensity (being amplitude) of laser return signal, (iii) determine that (for example estimating) is scanned scope or the distance R (t) of target with respect to scanning window, and then (iv) for example, transfers to the VLD blanking control module 150A in controller 150 by scope indication (estimating) signal form of digital data value (with), make it able to programme or suitable lasing light emitter (VLD) (being blanking) the function B (t) that stops using is set, be used for for laser drive circuit 151, with stop using under the particular case during each laser scanning cycle lasing light emitter 112A or 112B, in order to extinguish (closing) this laser scanning bundle according to lasing light emitter blanking function B (t) in this case during the laser scanning cycle, one group of scan-line data impact damper 160, cross over each complete scan-line data collected during complete the sweeping of laser scanning field (for example two scan-line data impact dampers, for being buffered in the data of collecting during direction of scanning) for being buffered in laser scanning bundle during each scan period, programming decoding processor 108, it processes the digitalized data be stored in described scan-line data impact damper 160 for decoding, and generates the symbol character data that means each bar code symbol of being scanned by the laser scanning bundle, I/O (I/O) communication interface modules 140, it is for being docked with main-machine communication system 154, and by the wired or wireless communication link 155 supported by symbol reader and host computer system 154 to its transmission symbol character data, and system controller 150, its for generating necessary control signal in order to control the operation in hand-holdable laser scanning bar code symbol reading system.

Especially, VLD blanking function B (t) can may mode specify according to a plurality of, includes but not limited to: (i) for symmetrical VLD blanking function B (t), by specifying a percentage of time (P who measures from the center of each scan period _a, P _a), indication has total duration T _sCeach scan period during VLD how long should be deactivated; And, (ii) for asymmetric VLD blanking function B (t), specify two different percentage of time (P that measure from the eccentric position of each scan period _a, P _b), indication has total duration T _sCeach scan period during VLD how long should be deactivated.The total duration T of each scan period _sCcan determine according to the sweep velocity of scan components, this sweep velocity will maintain substantially constant during scan operation.

As shown in Figure 12, laser scanning module 105 comprises a plurality of subassemblies, that is: laser scanning assembly 110, has solenoid 128 and rotatable scanning element (for example catoptron) 134, and it supports lightweight reflecting element (for example catoptron) 134A; Coil driver 111, for generating the solenoid 128 of electric drive signal with driving laser scan components 110; And laser beam sources 112A, for generation of visible laser bundle 113A; And beam-deflecting mirror 114, for laser beam 113A is deflected to the incident beam 114A towards the reflection mirror component of laser scanning assembly 110, it was crossed over the laser scanning field and may appear at the laser beam 114B that bar code symbol 16 wherein sweeps deflection simultaneously in system operating period.

As shown in figure 12, laser scanning module 105 typically is installed in optical bench, P.e.c. (PC) plate or also installs on other surface of laser scanning assembly, and comprise coil support part 110, for near supporting electric magnetic coil 128 (permanent magnet 135), and it is driven by scanner drive circuit 111, make it in scan components operating period, on the opposite pole of permanent magnet 135, generate magnetic force.Suppose between the attribute of permanent magnet 135 and permanent magnet 135 and solenoid 128 apart from substantially constant, the power on permanent magnet 135 and the scanning element that is associated thereof of putting on provides the electric drive current I to solenoid 128 during for scan operation _dC(t) function.Usually, the drive current I produced by scanner drive circuit 111 _dC(t) level is larger, and the power put on permanent magnet 135 and the scanning element that is associated thereof is just larger.Therefore, the scanning of scan module 105 sweeps angle α (t) and can directly by control under the control at controller 150, by scanner drive circuit 111, provide the drive current I to coil 128 _dC(t) level is controlled, as shown in Figure 2.In the disclosure, lock this drive current I _dC(t) will be to control the method for optimizing that (keeping constant) sweeps angle α (t) during scan operation.

Preferably, intensity detection module 143 is implemented in scan-data processor/digital quantizer 143, this scan-data processor/digital quantizer 143 can be implemented as asic chip, supports the circuit of analog-and digital-two types, and this circuit is carried out function and the operation wherein carried out.The function of intensity detection module 143 is many-sided: (i) process constantly simulation (or numeral) the scan-data signal returned, and the intensity of determination and analysis laser return signal (being amplitude); (ii) determine that (for example estimating) is scanned scope or the distance of target with respect to scanning window during each measurement period; And (iii) the range/distance indicator signal form of digital data value (for example with) is transferred to controller 150, for suitable VLD blanking function B (t), the laser beam scanned with the target for crossing in scanning field are set.Preferably, during each measurement period, by carrying out relative signal to noise ratio (S/N ratio) (SNR), measure, be scanned target and be determined (for example estimating) with respect to scope or the distance R (t) of scanning window, wherein in the working range (with respect to scanning window) of minimum SNR value and system, possible scanning distance farthest is corresponding, and in the working range of the highest SNR value and system, the shortest possible scanning distance is corresponding.Especially, module 143 can comprise the form of storage pre-calibration sweep limit contrast SNR value, and it can be used for determining of this range/distance.

And, during code density can be calculated the scope estimation procedure to the quadratic effect of the intensity of reflection (optics) the scan-data signal that detects in the photodetector place.In this alternate embodiment, module 143 also can be carried out estimated code density by the transformation in analysis mode scan-data signal, and then module 143 can be used as different code density scopes creates, the form that comprises pre-calibration sweep limit contrast SNR value.In the situation that measured by code density scope and the SNR of module 143 given estimations, these forms can be used to estimate to be scanned target zone.

Usually, system 700 is supported the manual triggers operator schemes, and the method that reads of the bar code symbol of the following stated.

In response to the manual activation of trigger switch 104, laser scanning module 105 generates the laser scanning bundle and it is projected by light-transmissive window 103, and crosses over the laser scanning field 115 of hand-holdable housing exterior, for scanning the target of this scanning field.This laser scanning bundle is generated by lasing light emitter 112B in response to the control signal generated by system controller 150.Scanning element (being mechanism) 134 sweeps the target of crossing in the laser scanning field at angle with the constant scanning being arranged by controller 150 during scan operation and makes this laser beam multiple scanning.Then, light is collected the light that is scanned code sign institute reflect/scatter on the target of optical device 106 collections from scanning field, and photodetector (106) detects collected light intensity (being photon energy) automatically, and generate the analog scanning data-signal corresponding to the light intensity detected during scan operation.In analog scanning data signal processor/digital quantizer 107, this intensity detection module 143 is carried out following functions: (i) process constantly simulation (or numeral) the scan-data signal returned; (ii) detect and analyze the intensity (being amplitude) of laser return signal; (iii) determine that (for example estimating) is scanned scope or the distance R (t) of target with respect to scanning window during each measurement period; And (iv) the range/distance indicator signal form of digital data value (for example with) is transferred to controller 150, be provided for the suitable VLD blanking function B (t) of laser drive circuit 151 for the scanning distance based on detected or scope R (t) at any time.VLD blanking function B (t) during each laser scanning cycle, specify VLD 112A will be when by laser drive circuit 151 automatically stop using (deenergizing), therefore and determine when visible laser will not be produced and not be transmitted in scanning field, electromagnetic scanning assembly 110 is attempted crossing over the laser scanning field during the laser blanking interval of appointment and is swept the laser scanning bundle along any target of its scanning pattern simultaneously.

With reference to Figure 15, the method for the operation in reading bar code symbols and control laser scanning bar code reader 100 has been described in more detail.

As indicated in Figure 15, start from starting frame A place by the process of 150 layouts of system controller, wherein all system units are activated, except laser instrument and scanning motor (being solenoid).Then the frame B place in Figure 15, system controller is determined and is triggered or whether the activation event (be trigger switch 104 be not operated the person manually press) occurs.

If the frame B place in Figure 15, trigger event is detected, system controller advances to frame C, and (i) utilize enough electric currents to activate laser diode and scanner drive circuit 111, sweep angle α (t) with the scanning that generates appointment, and (ii) then start timeout period timer T1.

Frame D place in Figure 15, analog scanning data signal processor/digital quantizer ASIC 107 processes simulation and/or the digital scanning data-signal returned, and automatically (i) measurement (for example estimating) is scanned scope or distance between target and scanner, (ii) determine VLD blanking function B (t), as the function of determined target zone/distance R (t), and (iii) for the programming of the given time during control procedure VLD blanking function B (t).

Frame E place in Figure 15, the system controller order, in data buffer 160, is buffered in whole scannings during the current scan period and sweeps on angle the complete scan line data collected for direction of scanning.Scan-data from each direction of scanning is buffered in different scan-line data impact dampers.

Frame F place in Figure 15, system controller determines that decoding processor 108 is whether based on collecting and be buffered in sweep trace in scan-data impact damper 160 and the decoding bar code sign.

If the frame F place in Figure 15, bar code symbol is not yet in the scan-line data of buffering decoded (that is, reading), and system controller advances to frame G and determines whether to reach timeout period T1.If also do not reach timeout period, system controller is back to frame D, and the processing scan data signal is determined target zone and upgraded VLD blanking function B (t), if necessary.Thereafter, system controller advances to frame E, and attempts collecting in remaining time period T1 and the decoding scan-data.If reached timeout period at frame G place, system controller advances to frame GH, sends the decoding failure notification to host computer system, and then at frame I place, stop using this lasing light emitter and scanning motor, and then turns back to frame B, as shown in Figure 15.

Utilize the described novel control procedure of Figure 15, this bar code symbol reader has ability and dynamically adjusts visible laser scanning beam during each laser scanning cycle from effectively emission or time of not launching of VLD 112A, and controls thus and/or maintain during bar code symbol reads process and be projeced into length and the strength characteristics that is scanned the sweep trace on target.In some applications, length of scanning line L _sLcan be maintained substantially constant being scanned on target, and irrelevant with scanning distance R (t).In other embodiments, in the preset limit of the different sensing ranges for scanning distance R (t), length of scanning line L _sLbe maintained substantially constant being scanned on target.In another embodiment, the end of each sweep trace can be truncated, bright spot or focus when eliminating its direction of laser scanning Shu Fanzhuan during scan operation.

some modifications of easily expecting

Although illustrative embodiment discloses by the 1D laser scanning module and has detected the visible and/or invisible bar code symbol on target, but should be understood that, also can use the laser scanning module of 2D or grating type, with scanning 1D bar code symbol and 2D stacked linear bar code symbol, and generate the scan-data of processing for decoding.

Although hand-holdable laser scanning system has been described, but should be understood that, these laser scanning systems can be packaged in portable or mobile data terminal (PDT), and wherein this laser scanning engine starts scanning in response to reception from the scan request of the host computer 154 in PDT.And, this laser scanning system can be integrated in modular compact case and be installed in the stationary applications environment, within code sign reading system such as (counter-top) scanner of counter top, inner kiosk system (being retail kiosk), oppositely vending machine, wall installation, but and within transportation system's (being machine), within forklift, wherein need scanning may be positioned at the scope that exposes thoroughly with the target (for example chest) of optional position (for example apart from scanning system nearly more than 20 feet) on code sign.

In this hard-wired application, trigger pip can generate in the following way: the self actuating switch (i) driven by IR or LED sensor, (ii) be positioned at remote location (for example, near the forklift pilothouse driver) or on being positioned at system shell the hand switch of optional position.And, during hard-wired application, the left side of laser scanning line, right side or middle body can be defined in the center of the VLD blanking function B (t) adopted in the laser scanning module of system.

And, illustrative embodiment reads and should be used for being described in conjunction with various types of code signs, this application relates to 1D and 2D bar-code structure (for example 1D bar code symbol and 2D stacked linear bar code symbol), should be understood that, the present invention can be used to read (i.e. identification) intelligent form of machine-readable indicia, data mode (dataform) or encoding of graphs arbitrarily, includes but not limited to bar code symbol structure, alphanumeric character identification string, person's handwriting and the diversified data mode that maybe will develop known in the art.Hereinafter, term " code sign " should be regarded as comprising all this information bearing structures and other encoding of graphs intelligence form.

The bar code symbol reading system based on digital imagery that should be appreciated that illustrative embodiment can be revised according to variety of way, and these modes will become apparent the those skilled in the art that benefit from novel teachings disclosed herein.All this type of of its illustrative embodiment revise and the scope of the claim that modification should be regarded as being that this is appended within.

Claims

1. the system for the code sign that reads scanning field comprises:

For generating the source of light beam; And

Scanning mechanism, for crossing over scanning field and to sweep angle, described light beam being scanned along sweep trace during the scan period;

Wherein, during each scan period, described source generates described light beam according to the blanking function.

2. according to the system of claim 1, wherein said source does not generate described light beam at the described end that sweeps angle.

3. according to the system of claim 1, wherein said scanning mechanism is scanned described light beam with the constant angle that sweeps.

4. according to the system of claim 1, comprise driving circuit, for providing current to described scanning mechanism, to realize the described angle that sweeps.

5. according to the system of claim 1, comprise the module of distance between the target for estimating described system and described scanning field, wherein said blanking function is determined by estimated distance.

6. according to the system of claim 5, comprise driving circuit, for the distance based on estimated, provide current to described scanning mechanism.

7. according to the system of claim 5, wherein said blanking function is realized the predetermined length of described sweep trace based on estimated distance.

8. according to the system of claim 7, the predetermined length of wherein said sweep trace is substantially constant in the scope of estimated distance.

9. according to the system of claim 1, comprising:

Photodetector, for detection of the light intensity from described scanning field reflection, and generate the first signal corresponding to detected light intensity; And

Processor, for the distance between the target of estimating described system and described scanning field based on described first signal;

Wherein said blanking function is determined by estimated distance.

10. according to the system of claim 9, wherein said processor generates the data that mean the mark in described scanning field based on described first signal.