CN1080073A - Band sweep limit and the self-adjusting laser scanning device of spot definition - Google Patents
Band sweep limit and the self-adjusting laser scanning device of spot definition Download PDFInfo
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- CN1080073A CN1080073A CN 92114849 CN92114849A CN1080073A CN 1080073 A CN1080073 A CN 1080073A CN 92114849 CN92114849 CN 92114849 CN 92114849 A CN92114849 A CN 92114849A CN 1080073 A CN1080073 A CN 1080073A
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Abstract
A kind of laser scanning device, wherein the size of the variation of beam waist and symbol actual range is irrelevant.Optics is a collector lens, makes its motion by encouraging a magnetic coil; The action of these lens and the scanning motion of laser beam are irrelevant, make the scope of beam waist produce variation continuous, gradually (for example continuous vibration), make that spot definition becomes suitable size on the symbol at some some place.The motion of described lens can with the scan-synchronized of light beam (such as using a spot definition to be maintained in the scanning several times).Change the scope of beam waist, until surpassing predetermined value, selective light spot size adaptively from described contrast of symbols in reflected light.
Description
The present invention relates to be used to read such as the used lasing light emitter of the laser scanning head of barcode symbol, the different piece of said symbol has different reflection characteristics.
Propose multiple optical reader and optical scanning system so far, be used to read the barcode symbol that appears on the label or on the article surface.Barcode symbol is a kind of indicia patterns of weaving into code, is made up of the vertical bar that a string width does not wait and each interval does not wait, and vertical bar has different reflective characters with the interval.Reader and scanning system convert this pictorial symbolization light-electricity to electric signal, and electric signal is decoded into again to indicating article or to the numeric character of its some feature description.This symbol often is expressed as digital form, gives the data handling system of point of sale, manifest check etc. as input signal.By disclosed such as United States Patent (USP) 4251798,4369361,4387297,4409470,4760248 and 4896026, all these patents have transferred the application's assignee to this medium-sized scanning system.
Disclosed as in the above-mentioned patent some, an example of this scanning system particularly places the handhold portable laser scanning head that is supported by the user, and its shape makes that the user can be with this scanner head, exactly, be the beam alignment target, reading symbol.
Light source in the laser scanner is generally gas laser or semiconductor laser.Adopt semiconductor devices, the light source of doing in the scanning system as laser diode is particularly suitable, and because of its size is little, price is low, and power demand is low.Laser beam Chang Youyi collector lens is shaped to the light beam of the convergent waist at a branch of middle part optically, and its beamwidth until minimum, reaches waist along with apart from from large to small in other words, increases later on again.Focus on this Shu Guang, cause the luminous point that obtains a required size in the position at target place; It usually is the position that waist is arranged at the target place.The size that preferably is chosen in target place luminous point is equal to different light reflectivities zone approx, i.e. minimum width in the vertical bar of barcode symbol and the interval.
Barcode symbol is made up of a plurality of vertical bars or unit, and they are often for having the rectangular shape of multiple possibility width.According to one group of rule, the particular arrangement of these yuan is according to the one group of rule or definition one character of code used or used " symbolic notation " defined.Vertical bar is determined by code used type that with relative size at interval they are equivalent to vertical bar and physical size at interval.The represented number of characters of per inch bar code is called character density.For the required character string of encoding, the group of unit connected together forms complete barcode symbol, and each character is by its corresponding element group representation.In some symbolic notation, represent the wherein beginning and the termination of bar code with distinctive " initial " and " stopping " mark.Some kinds of different barcode symbol representations are arranged.These symbolic notations comprise that such as UPC/EAN Code 39, Code128, Codabar and " intersecting 25 yards " (Inter leaved 2of5) etc.
In order to increase, several new barcode symbol representations are proposed recently to the data volume that can represent on the surf zone of sizing maybe can store.A kind of in the middle of these new coding standards, Code49 utilize and pile up the multirow symbol vertically and come place of water level land extension vertical bar, introduce " bidimensional " notion.Just there are a few row's vertical bars and intermittent pattern to replace a unique row.United States Patent (USP) 4794239 has been described the structure of Code49, thereby classifies it as list of references.In the scanning system of prior art, utilize lens or similar optics, make light beam have the target of barcode symbol along the light path directive.
Scanning realizes along straight line or the inswept repeatedly symbol of a series of straight line by light beam.Sweep unit can make spot wobble pass through barcode symbol, and is following sweep trace and crossing this symbol, perhaps scans the visual field of scanner, perhaps the two double doing.Scanning system also comprises sensor or photodetector, in order to detect the light from this symbol reflected.Therefore, this photodetector should place in the scanner or in light path, has the visual field of crossing and exceeding symbol slightly.A part is detected from the light of barcode symbol reflection, and converts electric signal to, and electronic circuit or programming system become numeral with the data of the barcode symbol representative that is scanned with the electric signal decoding.For example, the analog electrical signal from photodetector usually is converted into the pulse width modulated digital signal that has with vertical bar and the corresponding width of developed width at interval.After this, sort signal is decoded into the binary representation that is encoded in data in this barcode symbol, and is expressed as the letter or number character according to specific symbolic notation.
Decode procedure in the known scanning system carries out usually as follows.Demoder self-scanning device receives the width modulation digital signal, the algorithm of carrying out in the programming system this scanning of setting about decoding simultaneously.The initial sum stop element during if successfully and fully decoding scans and each symbol therebetween, then decode procedure finishes, and provides to the user and reads the indication of finishing (such as beep sound of green glow and/or audible).In addition, demoder receives next scanning, carries out the decode operation again of relevant scanning, and so on, until the scanning that obtains complete decoding, perhaps no longer can more be scanned.
After this, according to specific symbolic notation such signal decoding is become to be encoded in the binary representation of the data in the barcode symbol, and be expressed as the letter or number character.
Print barcode symbol with different density.For example, high density barcode symbol (live width≤5 mils) is used among a small circle (as integrated circuit), symbol that information density is big; And for example low-density bar code (live width 〉=50 mils) is used for storage packing (as the UPC/EAN bar code) and container.Usually minimum widith (as the minimum widith of bar unit) is suitable in the width of the light beam of the inswept barcode symbol of selection and the variant reflective character zone, thereby needs to read with the light beam of different in width the bar code of different densities.In addition, the bar code of same density can be placed in from laser scanning head different distance place, it is necessary to the size that changes luminous point from the scanner head different distance corresponding to numerous.
Conventional laser scanner has a collector lens to come focussed laser beam, makes the size of luminous point aim at the zone that barcode readers will be worked.Zhuan Pei focusing system often makes the scanner front that one " blind area " arranged like this, and with regard to scanning, spot definition there is too big.Have, such scanner must monitor the luminous point size simultaneously through adjusting collector lens along optical axis in manufacturing plant, then these lens is permanently secured to the position that reaches required spot definition, makes this scanner focus with this again.This step is the step of spended time more relatively, thereby has increased the cost of manufacture of laser scanner.
For improving the scanner of this fixed-focus, various suggestions have been proposed.Bergstein is at the U.S. Patent application U.S.S.No7/503 of first to file, 374 have disclosed a kind of non-focus optical system, wherein laser beam is collimated, and its width (or luminous point size) is almost kept constant (also promptly reducing the shape of beam waist as much as possible) in very wide scope.People's such as Krichever United States Patent (USP) 4808804 expressions move into and shift out the laser beam light path to different collector lens elements, move laser diode along optical axis simultaneously, to change the spot definition of operating distance and/or light beam.The United States Patent (USP) of Gabeler provides a kind of device of reading bar code for No. 4920255, it adopts ranging system to detect the surf zone of band bar code, and is defined in the position (driving a stepper motor along the laser focusing optical device from the signal of this ranging system output) of the optical device of focussed laser beam on the bar code with detected zone.The device that the United States Patent (USP) of Drucker discloses a kind of variation No. 4831275 in order to revising the light from barcode symbol reflection optically, thereby changes the distance that this symbol focuses on the photodetector in barcode readers; This technology comprises the variation of lens shape, moves the aperture along light path, and mobile mirror (or fiber optic cable) also provides row's sensor, and they each focuses on effectively in different zones.United States Patent (USP) 4,333, disclosed for No. 006 with multiple by the resulting varifocal holograph of rotary CD figure in different overlap distance zone focusings.
In general, the present invention is its feature with laser scanning head, and wherein the actual range of the variation of beam waist and barcode symbol size is irrelevant.In a preferred embodiment, optics is a collector lens, makes its motion by magnetic coil; The motion of lens and the scanning motion of laser beam are irrelevant, so that obtain a continuous gradual change (as continuous oscillation) in the beam waist scope, thereby at certain some place that changes, the luminous point size on the barcode symbol is a suitable dimensions.In another preferred embodiment, the motion of lens and beam flying synchronously (such as, same spot definition can be maintained in the several times scanning).
In another preferred embodiment, surpass a predetermined value by the scope that changes beam waist until the contrast in the barcode symbol reflected light and come selective light spot size adaptively.This technology has the advantage that surpasses other method in fact, shortened the required time of decoding such as it, obtained decoding more accurately, and reduced optics amount of movement (so, along with the result of this motion, also reduced the wearing and tearing and the energy consumption of mechanical hook-up).This adaptive approach is obtained the advantage of bar code scanner commonly used; Same scanner can be used for different scopes, even for those different density situations.But, usually be in one lasting period, it repeatedly to be used in same scope and same density.By the scope with a tight waist of selective light adaptively, this scope can be set and keep one lasting period, perhaps only does the adjustment that does not often run into seldom.Can realize decoding (because saved those scopes in unfavorable value, test the consumed time of wanting) so quickly, and decoding also accurate further (because of the luminous point size that can regulate step by step on the light beam, even most of the time need not to move).
The present invention has the advantage that width of light beam changes, and the scanning of various density is provided various scopes.Resemble the sort of practice of attempting to reduce or eliminate the waist shape shape of laser beam in the afocal system with it, it would be better to that the present invention adopts waist shape shape for progress.For any given barcode symbol scope, be to enlarge the spot definition on this symbol, the position of mobile waist is located at the back or the front of symbol.Like this, in any broad barcode symbol range, can reach the broad variation of spot definition, this just makes same laser scanning head can be successfully used in the multiple different application.
An advantage more of the present invention is " blind area " that can reduce the scanner front greatly.
Another advantage of the present invention is to avoid adjusting in manufacturing plant focus fully, and like this, even to being used for the scanner of a kind of scope, a kind of density, the present invention is still favourable, even to simple scanner head, and it is manufactured cost and is still reduction.
The present invention has avoided complicacy and has used independent scope to seek sensor and determine the target area, indicates the required expense of focal variation again.Method for synchronous of the present invention is specially adapted to the bar code scanner of high-velocity scanning, the scope of light beam in this method (being the scope of beam waist) is shifted to another section from a section, and all remains in each step and to have one on the fixing section and give fixed scan period number.
Other characteristics of the present invention and advantage will be obvious from following preferred embodiment and claim.
Fig. 1 is the laser scanning head sectional view that has LASER Light Source of the present invention;
Fig. 2 is the sectional view along the 2-2 line of Fig. 1, the position of expression laser zoom system, pancreatic system and additional optical photodetector;
Fig. 3 A is the sectional side elevation along the 3-3 line of Fig. 2, an embodiment of expression LASER Light Source of the present invention;
Fig. 3 B is the partial longitudinal section along the 3-3 line of Fig. 2, the hole of a distortion of expression;
Fig. 4 is the sectional view along the 4-4 line of Fig. 3 A;
Fig. 5 is the sectional view along the 5-5 line of Fig. 3 A;
Fig. 6 is the sectional side elevation along the 3-3 line of Fig. 2, another embodiment of expression LASER Light Source of the present invention;
Fig. 7 is the sectional view along the 7-7 line of Fig. 6;
Fig. 8 is the sectional view along the 8-8 line of Fig. 6;
Fig. 9 is an embodiment sectional view again of LASER Light Source of the present invention;
Figure 10 is the sectional side elevation along the 3-3 line of Fig. 2, another embodiment of expression LASER Light Source of the present invention;
Figure 11 is the sectional view along the 11-11 line of Figure 10;
Figure 12 is the total index path and the circuit block diagram of one embodiment of the invention;
Figure 13 is the graphic representation to the laser spot sizes variation of one embodiment of the invention;
Figure 14 is the graphic representation to the laser spot sizes variation of another embodiment of the present invention;
Figure 15 is the total index path and the circuit block diagram of one embodiment of the invention;
Figure 16 is the graphic representation to the laser spot sizes variation of further embodiment of this invention;
Figure 17 is the different range in laser beam, also is the graphic representation of the diverse location place laser beam waist shape shape of collector lens;
Figure 18 and 19 is the graphic extensions that concern between the position of collector lens and the laser beam scope;
Figure 20 is the longitudinal section of another embodiment of laser scanning head of band LASER Light Source of the present invention;
Figure 21 is the longitudinal section of the another embodiment of LASER Light Source of the present invention.
Fig. 1 is illustrated in for example, and United States Patent (USP) 4897532(classifies list of references as) in the manual laser scanner head 10 described comparatively fully.Other type laser scanning head also can be used by the present invention.Laser scanning head is generally used for reading the symbol of being made up of the part of different reflective characters.Such symbol comprises black, white industrial barcode symbol, as Code2=39, Codabar, " intersecting 25 yards " (Interleaved 2 of 5), also comprises pervasive UPC bar code.Said symbol also can be any letter character and/or numerical character.Said symbol is placed in the background scope, there, symbol or at least its part compare with background and have different reflective characters.Reading this symbol especially is of value to the identification of automatic control occasion and object.
Referring now to Fig. 1-2,, scanner head 10 has gun-type shell usually, and it has handle portion 12 and main part 14.Manually operated trigger 16 starts scanner, makes lasing light emitter 18 along optical axis 20 emission beam of laser.Laser beam is subjected to scanning reflection mirror 22 reflections, penetrates through window 24 self-scanning heads, shines (sign field of scanner head front is represented not in scale among the figure) on the symbol 28.Scanning reflection mirror 22 is contained on the high-velocity scanning motor 26, and alternately this catoptron of reciprocally swinging makes back and forth inswept symbol 28.Light from symbol reflected is assembled by concave spherical surface collecting lens 32 usually, and the catoptron 22 that reflected light is defined as a taper 30(reflection lasering beam is a little plane mirror, places along one side of concave spherical surface collecting lens 32).Reflected light taper 30 is pointed to preferably photodiode of photodetector 34(by mirror 32), the electric analoging signal of the variable intensity of light that this detector generation one performance records.Mirror 32 also can be used to focus on and along with a branch of aiming light of the same axle guiding of laser beam.Said aiming light is by diode (LED), incandescent source or the xenon flash tube of light source 36(such as visible emitting) produce, and reflect towards concave spherical mirror 32 by cold reflector 38.Said cold reflector can see through the light of optical maser wavelength, the but light of reflection aiming light wavelength.
Change 3A with the aid of pictures, 3B, 4 and 5 now, represented a preferred embodiment of lasing light emitter here.Laser diode 50 is supported in the laser bench 51, and laser bench is clamped on the pedestal 53.Laser diode is along optical axis 20 emission beam of laser, and this Shu Jiguang is subjected to collector lens 52 and focuses on; Said lens are subjected to the driving of magnetic coil 54, vertically move along optical axis.Pass hole 56 from the light of lens 52 outgoing.The hole can be such as circular open (Fig. 3 A) or rectangular slot (Fig. 3 B).Lens 52 are supported in the support unit 60; 56 in hole is formed in the bore components 58, and bore components is enclosed within on the lens.Lens support unit 60 is bearing on a pair of springs 62, makes it can be along the optical axis lengthwise oscillations.Springs is also supporting two permanent magnets 64,66 and soft iron parts 68.By changing the motion that magnetic field intensity that magnetic coil 54 produced realizes collector lens.
Fig. 6～8 show another preferred embodiment of lasing light emitter 18.Laser diode 50 is supported in the bearing 51; Bearing is clamped in the pedestal 53.Pass through collector lens 52 and hole 56 by this diode emitted laser bundle along optical axis 20; The hole can be round opening (Fig. 6) or rectangular slot (not shown, but similar to Fig. 3 B).The hole is formed in the bore components 58; Bore components is enclosed within on the lens.In the present embodiment, realize the motion of collector lens by being contained in magnetic coil 54 on the lens support unit 60; This coil is with lens movement.Lens support unit 60 is bearing on a pair of springs 62.The center of permanent magnet 64 is porose, passes for laser beam, and it combines with soft iron parts 68, is placed in position with respect to laser diode.Along with the increase of the alternating current amplitude of giving coil, this coil is pulled to permanent magnet 64, and then enters in the cingens soft iron parts 68.Magnetic coil is placed on the moving component, and permanent magnet that will be heavier and soft iron parts are placed on the fixed part, this has just reduced the quality that must move, thereby has improved the high frequency response of lens movement.Also express the photodetector 34 that is anchored on the pedestal 53 among Fig. 7.
Fig. 9 illustrates the 3rd preferred embodiment of lasing light emitter.In this is implemented, magnetic coil and soft iron parts 68 are fixed on the pedestal 53,64 of permanent magnets and moving lens are fitted together.Laser emits from the laser diode 50 that is supported in the laser bench 51, passes the perforate in collector lens 52, hole 56 and the permanent magnet 64.Increase the magnetic field intensity of coil, lens 52, lens support unit 60 and permanent magnet 64 promptly move towards magnetic coil 54.
The 4th preferred embodiment of lasing light emitter represented in Figure 10～11.Laser diode 50 is clamped on the pedestal 53; Collector lens 52 is supported on the lens support unit 60, is enclosed within above it by the bore components 58 that has aperture 56.Lens support unit and bore components are all striden and are placed in the tubular seat frame 61.Volute spring 62 hinders lens and the lens support unit moves towards laser diode.Permanent magnet 64 moves with lens subassembly, and this magnet is placed in the soft iron that is surrounded by magnetic coil 54 and overlaps 68 the insides.The increase supply current amplitude of magnetic coil 54 makes permanent magnet 64 be pulled to magnetic coil, thereby has shortened the gap between collector lens and the laser diode.
Any in described these four kinds of lasing light emitters all can be used with three kinds of preferred lens control system.Figure 12 has represented first kind of lens control system, and picture in picture is expressed basic light path with separating.Be subjected to collector lens 52 from laser diode 50 emitted laser bundles and focus on, again by the catoptron 22 inswept barcode symbol of swinging.Show by focus lamp 32(from the light of bar code reflection and to make lens) accumulate in and focus on the photodiode 34, the output of diode obtains processing with known manner of the prior art.This signal amplifies through prime amplifier 80, obtain one and can represent the simulating signal that is scanned bar code reflection characteristic variation characteristics, this simulating signal converts numeral to by digitizer 82 thereupon, and digital signal is by demoder 84 decodings, provide a row by the represented character of bar code, this character that solves can be shown on the display 86 and/or by interface 88 and deliver in the digital machine 90.
The control circuit of lasing light emitter and scanning reflection mirror also is shown among Figure 12.Under the control of motor driver 92 and clock 94, make catoptron 22 swings by motor 26.The position of collector lens 52 drives magnetic coil and continuous oscillation by magnetic coil driver 96.
Figure 13 diagrammatically expresses the variation of the laser beam focusing that realizes by the condenser lens vibration.Following curve map is represented the motion of collector lens, and this motion is expressed as piecewise linear, but it also can be expressed as sinusoidal form or other form.Above the scanning motion of graphical representation laser beam, being superimposed upon on the curve is that this laser beam is in some " luminous point size " constantly.See for clear, the demonstration of minority " luminous point size " only is shown.For example, at A constantly, collector lens is in an end point place of its stroke, at this moment corresponding to the spot definition of minimum; B constantly, lens have walked to corresponding the some place of medium luminous point size; In the C moment, lens have arrived its opposite end point place, corresponding to the spot definition of maximum.This example is called as the quasi-stationary motion of lens, because this motion is very slowly with respect to sweep velocity.
Figure 12 also illustrates second preferred lens control system.Under same driving beam flying catoptron clock control, frequency divider or similar circuit are being controlled moving of collector lens.As shown in Figure 14, in this embodiment, lens move between three different positions.Lens maintain the A place, position of spot size diameters minimum, four inswept barcode symbol.Afterwards, lens move to the B position, and there corresponding to medium sized laser spot, it remains in this position, four inswept barcode symbol once more simultaneously.Subsequent, lens move on to the C position, corresponding there maximum sized laser spot, and it maintains there, four inswept barcode symbol again simultaneously.At last, lens are retracted the A position, restart whole circulation.
Figure 16 shows the 3rd, also is most preferred lens control system embodiment.This is an adaptive system, and wherein the position of collector lens should be calibrated along with the feedback from photodiode.When starting the trigger on the laser scanner, lens are initially located in the C position, in this spot definition corresponding to maximum.During so-called Phase I, lens along with spot definition reduce slowly move, send signal until the output of prime amplifier 80 to controller 98, this time point size has been reached for and has obtained the enough sizes of grade that required reflected light changes.Be called as on the point of " capturing " at that, controller 98 ends the position of collector lens admittedly, and scanning continues (stage II).Change a situation, if the output of prime amplifier 80 reduces, " capturing " disappears, and its receptible position is sought in the designated beginning of collector lens once more.
When simulating signal has enough contrasts, just capture.Contrast C can be expressed as
C = (I
max- I
min)/(I
max+ I
min)
I wherein
MaxBe the peak value of simulating signal, corresponding to the light that reflects from colorama (i.e. white) district of bar code, and I
MinBe the minimum value of simulating signal, corresponding to the light that reflects from aterrimus (the being black) district of barcode symbol.When surpassing, contrast C gives fixed restriction, promptly
C≥Co
In time, just capture; Here Co is a constant.The Co value that is adopted depends on that analog signal conversion becomes the digitizer characteristic of digital signal.The digitizer characteristic is good more, and the value of Co can be more little.
So far, we have introduced laser beam " spot definition ".Change now and see Figure 17, can explain the connotation of " spot definition ".Do not collimated fully by laser diode 50 and collector lens 52 resulting laser beam.The width of light beam is different along optical axis.So for example when collector lens is in end point place of its stroke, the laser beam of correspondence should have and is labeled as E among Figure 17
1Beam envelope (scale does not draw).The width of light beam changes, but minimum widith is at the position of " waist " W
1The place.Along with the other end of collector lens towards its stroke moves, the waist of laser beam also leaves light source and moves.At collector lens diverse location place, several beam envelopes that laser beam is determined are as beam envelope E shown in the figure
2～E
7Be important to note that leave light source and move along with the position of waist, the size of laser beam waist increases reposefully; So, W
2Compare W
1Big or the like; When collector lens arrived the other end of its stroke, waist was of a size of W
7
In any given collector lens position, the variation of width of light beam helps accessing the variation at same section place " spot definition ".So, being positioned at position X such as the barcode symbol that is scanned, the size of luminous point just can change adaptably with the variable density of bar code.Along with collector lens corresponding to beam envelope E
4The position, it is minimum that spot definition should reach, so obtain waist W
4Make collector lens from E
4The position is removed, and moves on to corresponding to beam envelope E
3And E
2The position, can obtain the luminous point of large-size; At corresponding beam envelope E
3, E
2During the position, spot definition is respectively X
3And X
2Section at other can obtain same spot definition variation.So, be used to obtain the spot definition variation of each section by the original shape of the laser beam that laser diode produced.
Figure 18～position of 19 expression collector lenses and the relation between the laser beam section (being the position of beam waist).The first half of Figure 19 is represented the situation before the zoom.Beam waist and lens apart from l
20Can be expressed as focal distance f and light source (being laser diode) position l
10Function, l wherein
10Equal f+ △.So we have before the zoom
1
20= (f ( f + △ ))/(f + △ - f) = (f
2)/(△)
Behind the zoom, lens move past an amount δ, cause the position of beam waist to move on to 1
2, this is 1 years old
2Can be expressed as
1
2= (f ( 1
10+ δ))/(1
10+ δ - f) = (f ( f + △ + δ))/(△ + δ)
= (f
2)/(△ + δ) = (1
20)/(1 + ( δ/ △))
Thereby have
(1
2)/(1
20) = 1/(1 + ( δ/ △))
It is actual applicatory that (δ/△) scope is
-0.5△≤δ≤△
In case δ surpasses this scope, work will become unstable or produce undesirable high power consume (Figure 18).
Distance in the corresponding image, i.e. the change of light beam is
l
2＝（0.5-2.0）l
20
Another embodiment of the present invention shown in Figure 20 and 21.Laser scanning device can be the barcode readers 100 with manual rifle type profile.But, obviously the scanner profile of other kind also all is easy to be applicable to the present invention.Reader 100 has the lever 153 of pistol grip shape, and the trigger 154 that can pull is arranged on it.Use this reader, can make user excitation laser beam 151 and detector circuit again when aiming at the symbol that to read, so, just can save the life-span of battery when if this device is power autonomous.Lasing light emitter, detector 158, optical system and signal processing circuit are housed in the light plastic shell, also have CPU140 and power supply or battery 162.The light inlet window 156 of shell 155 front ends can make outgoing beam 151 leave away, and the reflected light 152 that makes into enters.Reader 100 is designed to aim at bar code by the user in the position that makes this reader 100 leave barcode symbol one segment distance, that is to say that reader does not contact or crosscut moves past symbol.Usually, stipulate the manual barcode readers of this class will from the contact symbol to the distance of leaving several inches of symbols or even farther region operation it.
And for example further described among Figure 20, can be adopted a suitable lens 157(or poly-lens system) scanning light beam is focused on the barcode symbol that is on the suitable reference plane.Light source 146 is set, as semiconductor laser diode, so that a branch of light is introduced the optical axis of lens 157; Light beam passes a partially silvered mirror 147 and other required lens or beam-shaping mechanism, and when cocking 154, they are added on the scan module 160 that has started with the catoptron or the sweep unit 159 of swing.United States Patent (USP) 5015833 has been described a kind of optical devices that changed, and it is listed in list of references.If it is only sightless that light source 146 produces, aiming light just produces a visible light luminous point, and this luminous point can be fixed or resemble and be scanned the laser beam; The user will aim at barcode symbol with reader with this visible light earlier before cocking 154.
In order to utilize scanister to make it that varifocal/self-focusing ability be arranged, its essence also can scan and read out in from this installs symbol on the various scanning distances place target, this reader 100 comprises the electromagnetism zoom lens control device (as shown in Figure 20) of optical system or lens 157, in order to changing the focal position, also promptly change from the light beam of light source 146 ejaculations or the waist position of laser beam.
Top described for realizing, Figure 21 provides graphic representation especially, this electromagnetism auto focus/zoom device is provided for shell mechanism 200, shell 200 has the main part 202 of tubulose, preferably be made up of nonmetallic materials or plastic material (as polytetrafluoroethylplastic plastic etc.), it has the inner basic columniform profile that is.Just be fixed on an end of tubular body portion 202 in order to the light source 146 of emission light beam; Said light source can be such as by lead 204 and power supply 162(battery for example) laser diode that links to each other.Light source or laser diode 146 are contained in the sleeve 206, and this sleeve can be brass, it be threaded or tightly the lock mode be fixed on the end 208 of tubular body portion 202.
At the other end of main part 202 or say that second end, 210 places form a ring groove 212, it is suitable for the winding around 214 of ccontaining electric excitation, and this coil and AC power are joined.It is little that the internal diameter in the hole 216 that said ring groove 212 forms at second end, 210 places of tubular body portion 202 stretches to the first end internal diameter that light source 146 is housed than main part 202.
With optical lens 157 or the equivalence optical focusing system be arranged in the tubular body portion 202, with cylindrical surface 218 sliding contacts; Permanent magnet 222 is connected on described lens or the focusing system by the intermediary of external lining 224, so that it can move together with optical lens 157.Magnet 212 has center through hole 226, makes the light beam or the laser beam of sending and passing collector lens 157 from light source 146 pass the end 210 of directive main part 202 thus.Optical lens 157 that connects by lining 224 and magnet 222 endwisely slip along wall 218, because the friction factor that is present in therebetween is very low freely in the inner boundary the inside of cylinder blanket main part 202.
Second end of main part 202 has the hole 216 of less internal diameter, hole 216 outer ends be partly with screw thread 228, be suitable for being connected with complementary threads on the sleeve pipe 230; Sleeve pipe 230 is made by non-ferromagnetic metal material or plastic material, is suitable for spiral shell button ground manhole appendix 216.The outer end of sleeve pipe 230 is by plate shape window 232 sealings of printing opacity, and this window does not pass luminous energy with not being obstructed thus, but the inside of shell 200 and extraneous airtight separating.
Optical lens 157 joins with volute spring 238 towards the end face 234 of light source 146; Spring 238 is pressed close to the edge of lens 157, and spring 238 extend into along 240 the insides, circular passage between surface 218 sleeve pipes that extending 242 and light source 146 parts towards light source 146 simultaneously.Magnet 222 contacts with second volute spring 244, and this spring is stretched between the end surfaces 248 around aperture 226, the face 246 that deviates from lens 157 and sleeve pipe 230.Thereby, the interaction that the elastic force of by volute spring 238 and 244 adverse effects that the consideration said apparatus provides provides, and be screwed onto the axial difference adjustment of the sleeve pipe 230 of 216 the insides, hole, optical module 157 that connects together and magnet 222 are maintained in main part 202 the insides of shell 200 and give on the axial location fixed or reference.The home position or the reference position of beam waist or laser beam waist determined in this position; Light beam or laser beam are sent from light source 146, pass optical aperture 226 and window 234 in optical lens 157, the magnet 222, so that the symbol on scanning and the reading object.Because the inside of shell 200 is with respect to the external world or external condition sealing, so the air that is comprised in the shell provides a kind of buffer action in essence, just in case scanister falls or suffers unexpected external impact, it is just as a kind of shock absorbing medium.This meticulous optical module that will protect wherein and be comprised is avoided the infringement that this external force causes.
Can be used as adjustable angle scanner/zoom scanner according to scanister of the present invention or reader 100, this class scanner can leave (even contacting) within several inches of this scanister to the symbol scanning of some feet distances and read to being positioned at; For example, from 5 inches in 15 feet scope of work, all need not to do big adjustment and/or in scanister, add additional parts.Like this, send from light source 146 for moving, pass the light beam of optical aperture 226 in condenser lens 157 and the magnet 222 or the focus of laser beam, the present invention has thought over the electric excitation of coil 214, so that alternately, electromagnetic ground attracts and repulsion magnet 222, cause magnet 222 by optical lens 157 and with holes 226 in tube-like envelope main part 202 the insides, axially move back and forth along wherein cylinder shape inner wall face 218.Above-mentioned for realizing, by suitable lead 250 ac-excited electric current to be given in the coil 214, lead 250 links to each other with power supply-and perhaps be the power supply of light source 146, so that add to the electromagnetic field of magnet 222 change in polarity.This to-and-fro movement in the main part 202 of shell 200 of lens 157 and magnet 222 is opposite with the restoring force or the equilibrant effect of solenoid spring 238 and 244, and the latter tends to make optical lens 157 and magnet 222 to get back to initial rest position; On this position, beam waist is in to give decides scope.For reaching desired scope of work, the scope of the device axially reciprocating of being made up of optical lens 157 and magnet 222 is approximately leaves equilibrium position ± 15 millimeter; Be added to by the alternating current on the magnetic coil 214 generally in about 2～5 hertz frequency of operation, this is significantly less than the about 18 hertz normal scan frequency of this common class scanister.Therefore, this will provide a kind of (being quasi-stationary motion) autozoom effect that is essentially continous way, thereby in scanning process, the light beam of ejaculation or laser beam will reasonably be focused on the symbol of being read by this scanister, and regardless of the distance of scanister from this symbol.
Though the invention describes certain embodiments, the present invention has extensive applicability, so and does not mean that claim is limited on the given details.Following claim has comprised other embodiments.Various modifications and structural variation can draw, and but can not break away from the present invention.For example, the motion of collector lens can adopt small machine, piezoelectric-actuator or hydromechanical executive component to realize.
Claims (24)
1, a kind of lasing light emitter that is used for reading the laser scanning head of the symbol that has different reflective characters zone on the target comprises:
Be contained in the laser instrument that the laser beam that makes its directional transmissions on the pedestal is propagated along optical axis;
Along the optics that described optical axis is provided with, it is focused into described laser beam to have light beam waist, variable-width, and the width at beam waist place is littler than other position;
The device that described optics is vertically moved along described optical axis, the size of the action of this device and symbol actual range is irrelevant, makes the variation of beam waist position and the actual range of symbol have nothing to do.
2, lasing light emitter as claimed in claim 1 is characterized in that described optics is a collector lens.
3, lasing light emitter as claimed in claim 1 is characterized in that the described action that makes the device that optics produces relative motion and the scanning motion of said laser beam have nothing to do.
4, lasing light emitter as claimed in claim 1 is characterized in that the described device that makes optics produce relative motion causes the motion continuous, gradually of this optics, and corresponding to the beam waist scope continuously, gradually variation.
5, lasing light emitter as claimed in claim 4, it is characterized in that described continuously, gradually be changed to vibration, wherein the scope of beam waist is vibrated between minimum value and maximal value.
6, lasing light emitter as claimed in claim 1, it is characterized in that also comprising the motion of controlling described optics and the circuit of control bundle waist range thus, also comprise the scan-synchronized that makes described variation and the inswept described symbol of light beam, make described scope before further adjusting, keep constant circuit at the scanning times of being scheduled to.
7, lasing light emitter as claimed in claim 1, it is characterized in that also comprising adaptation control circuit, it surpasses the motion that a predetermined contrast value is controlled described optics by the variation that causes described scope continuously until the reflected light of being assembled by described laser scanning head, and the variation of control bundle waist scope thus.
8, as claim 1,3,4,6 or 7 described lasing light emitters, it is characterized in that described optics comprises collector lens, the wherein said device of optics motion that makes comprises magnetic coil, this coil is fixed with respect to described collector lens or laser instrument.
9, lasing light emitter as claimed in claim 8, it is characterized in that the described device of optics motion that makes also comprises the lens support unit that supports described collector lens, described lasing light emitter also comprises one or more flexible members, and they stop the motion that is caused by described magnetic coil.
10, lasing light emitter as claimed in claim 9 is characterized in that described flexible member comprises the springs that supports described lens support unit, makes it can be with respect to the longitudinally transverse movement of described springs.
11, lasing light emitter as claimed in claim 9, it is characterized in that also comprising permanent magnet, it is fixing with respect to one that moves with respect to magnetic coil among laser diode and the collector lens, make the magnetic coil of excitation can cause permanent magnet towards or leave this coil and move, and cause the interval variation of collector lens and laser diode.
12, lasing light emitter as claimed in claim 11 is characterized in that described magnet is fixed on the movable member.
13, lasing light emitter as claimed in claim 11 is characterized in that the stationkeeping of described permanent magnet with respect to collector lens, and described magnetic coil is with respect to the stationkeeping of laser diode.
14, lasing light emitter as claimed in claim 11 is characterized in that the stationkeeping of described permanent magnet with respect to laser diode, and described magnetic coil is with respect to the stationkeeping of collector lens.
15, a kind of adjustment is used to read the laser beam of the laser scanning head of symbol on the target, to change laser beam luminous point size on described symbol, obtain being suitable for reading the method for this symbol spot definition, wherein said symbol has different reflective character zones, described symbol is positioned at a scope with respect to described laser scanning head, and this method may further comprise the steps:
Lasing light emitter is set and from this light source along the optical axis emission of lasering beam;
Make this laser beam pass the optics that is provided with along optical axis, laser beam is focused into has light beam waist, variable-width, the width of laser beam waist is little than other position;
Move described optics along optical axis with respect to described lasing light emitter, this moving with the actual range of barcode symbol is big or small has nothing to do, and the variation of the beam waist scope that obtains thus is also irrelevant with the actual range of barcode symbol.
16, method as claimed in claim 15 is characterized in that described optics is a collector lens.
17, method as claimed in claim 15 is characterized in that the motion of described optics and the scanning motion of laser beam have nothing to do.
18, method as claimed in claim 17, the motion that it is characterized in that described optics are motion continuous, gradually, thus produce the beam waist scope corresponding continuously, variation gradually.
19, method as claimed in claim 18, it is characterized in that described continuously, gradually be changed to vibration, wherein the scope of beam waist is vibrated between minimum value and maximal value.
20, method as claimed in claim 15, it is characterized in that further comprising the motion change and the described light beam that make optics and cross the scan-synchronized of barcode symbol, thereby make described scope before further adjusting, keep constant giving fixed scanning times.
21, method as claimed in claim 15, it is characterized in that the variation that further comprises by the described scope of continuous generation surpasses the motion that predetermined contrast value is controlled described optics adaptively until the reflected light of being assembled by described laser scanning head, and the variation of control bundle waist scope thus.
22, method as claimed in claim 15 is characterized in that by encouraging a solenoid to realize the motion of described optics.
23, a kind of adjustment is used to read the laser beam of the laser scanning head of symbol on the target, to change laser beam luminous point size on described symbol, obtain being suitable for reading the method for this symbol spot definition, wherein said symbol has different reflective character zones, described symbol places in the certain limit with respect to this laser scanning head, and this method may further comprise the steps:
Lasing light emitter is set and from this light source along the optical axis emission of lasering beam;
Make this laser beam pass an optics along the optical axis setting, laser beam is focused into has light beam waist, variable-width, the width of laser beam waist is little than other position;
Move described optics with respect to lasing light emitter, make beam waist be in zone inequality, the position of described barcode symbol on, thereby make the size of the laser spot on this mark bigger than the size of waist.
24, a kind of method of making laser scanning head, by collector lens and mark on the directive target, this method may further comprise the steps the laser beam in such scanner head from laser diode:
One laser diode is set on laser scanning head, makes this diode along the optical axis emission of lasering beam;
Along described optical axis one collector lens is set, is used for laser beam is focused into and has laser beam waist, variable-width, the width at this beam waist place is little than other position;
Setting is moved the device of described collector lens with respect to described laser diode, changing the beam waist scope of described laser beam,
The circuit of the device of the mobile collector lens of control is set,
A position of determining with respect to laser diode collector lens is set, and need not adjusts the collector lens position for focussed laser beam.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92114849 CN1053052C (en) | 1992-12-23 | 1992-12-23 | Laser scanning device with automatic range and spot size adjustment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 92114849 CN1053052C (en) | 1992-12-23 | 1992-12-23 | Laser scanning device with automatic range and spot size adjustment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1080073A true CN1080073A (en) | 1993-12-29 |
| CN1053052C CN1053052C (en) | 2000-05-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 92114849 Expired - Fee Related CN1053052C (en) | 1992-12-23 | 1992-12-23 | Laser scanning device with automatic range and spot size adjustment |
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| Country | Link |
|---|---|
| CN (1) | CN1053052C (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100487599C (en) * | 1998-06-23 | 2009-05-13 | 株式会社理光 | Method adjusting a write unit and apparatus for adjusting a write unit |
| CN101529331B (en) * | 2005-04-28 | 2010-07-21 | 讯宝科技公司 | Monitoring scan mirror motion in electro-optical readers and image projectors |
| CN102289643A (en) * | 2010-06-17 | 2011-12-21 | 手持产品公司 | Intelligent indicia reader |
| CN107016308A (en) * | 2015-09-07 | 2017-08-04 | 电装波动株式会社 | Optical information reading apparatus |
-
1992
- 1992-12-23 CN CN 92114849 patent/CN1053052C/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100487599C (en) * | 1998-06-23 | 2009-05-13 | 株式会社理光 | Method adjusting a write unit and apparatus for adjusting a write unit |
| CN101529331B (en) * | 2005-04-28 | 2010-07-21 | 讯宝科技公司 | Monitoring scan mirror motion in electro-optical readers and image projectors |
| CN102289643A (en) * | 2010-06-17 | 2011-12-21 | 手持产品公司 | Intelligent indicia reader |
| CN102289643B (en) * | 2010-06-17 | 2016-06-15 | 手持产品公司 | Intelligent indicia reader |
| CN106022191A (en) * | 2010-06-17 | 2016-10-12 | 手持产品公司 | Intelligent optical code reader |
| US10621397B2 (en) | 2010-06-17 | 2020-04-14 | Hand Held Products, Inc. | Intelligent indicia reader |
| CN107016308A (en) * | 2015-09-07 | 2017-08-04 | 电装波动株式会社 | Optical information reading apparatus |
| CN107016308B (en) * | 2015-09-07 | 2020-06-02 | 电装波动株式会社 | Optical information reading apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1053052C (en) | 2000-05-31 |
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