JPS588021B2 - Fugo Label Oyomi Toruhouhou Oyobisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for reading encoded labels, particularly those employed in the food vending/supermarket industry and commonly used in the food vending industry universal product code “Uni
Versal Product Code 1 (UPC
) relates to a method and apparatus specifically designed for reading machine-readable indicia known as .

The aforementioned type of code is generally characterized as a line code consisting of a series of parallel light and dark lines of different widths that are straight in one direction and generally rectangular in shape.

Each character and digit of the code is represented by two dark lines and a light space.

For example, a complete description of this type of code can be found in "U.P.
C display specifications (UPC, SymbclSpecif
icatim)”.

This document was published in May 1973 by the Administrator of Universal Product Codes and UPC Labeling for the Uniform Grocery Store Product Code Conference, Washington, DC. C. distribution of
．． Number bank (DistributionNum)
ber Bank).

Recently, a variety of codes have been developed to give the supermarket/grocery industry the ability to label all products with machine-readable labels, i.e., to provide identification of merchandise via machine-readable computerized equipment. Numerous proposals have been made for this system.

The machine not only provides a complete and accurate inventory accounting system, but also substantially reduces the time and effort currently required to go through a check counter.

It is an object of the present invention to provide an improved system for such purposes.

In general, it is an object of the present invention to provide a commercially available product which reads such labels efficiently and accurately while reducing the possibility of unread conditions to a minimum and providing optimization of the system from an ergonomic point of view. An object of the present invention is to provide a method and apparatus for reading encoded labels.

Another object of the invention is to provide a particularly reliable method and apparatus that utilizes a laser beam scanning system with a single rotating part and yet provides complex scanning patterns with a low probability of non-reads. There is a particular thing.

Providing machine-readable labels to product packaging must begin with an assumption of the manner in which such packaging equipment will be processed at the verification counter.

Considering this in detail, it is assumed that a machine-readable code and a person who processes each package for a device that reads such a code is located at a verification counter, and that the goods are packaged there.

If the coded indicia on the item are not machine readable, a person, ie, a verifier, is required to manually enter the coded indicia by some suitable means, such as a cash register type keyboard or the like.

In addition to machine-readable line codes, the UPC display specification provides for other human-readable codes.

In order to obtain satisfactory use and acceptance of machine-readable codes and systems of the type described herein, the percentage of unreadable cases occurring at a given verification station is kept to an absolute minimum and the system It is imperative that the accuracy of the information is guaranteed.

If we look at the problem more closely, there are certain human elements that need to be satisfied.

After all, typical sized packages range in size from such small packages of gum to large heavy boxes of soap or packaged goods of rice.

Each of these articles is held in a reading window of some kind so that an appropriately encoded label is placed against the window so that the code can be read.

If we decide that the direction that crosses the movement direction of the product is the target direction, then 5
A target area of 6 to 6 inches wide allows the verifier to align the target without much restriction, thus defining an appropriate window width.

By providing a 5- to 6-inch target width, the matcher can easily print labels without first making the effort to align the labels in the window.
Items can be pulled across the window.

Although it is possible to make such windows even larger,
This increases the amount of scanning required to properly cover the window to the extent that the electronic logic required to decode the results must be done under technological limitations.

This unduly increases system cost and complexity.

If the direction in which the product moves is determined as the reach direction, the verifier will be able to move the product across the window by
You must reach across this dimension of the window.

If the 6 inch lateral dimension, ie, the target dimension, were also used in the elongation direction, ie, if a square shape was used, checker fatigue would result.

Therefore, it is desirable to minimize the read pattern and window in that direction.

A non-reducible minimum value is found by considering the size of the maximum area that the encoded label provides for reading.

for UPC) and 2 inches high.

Analysis of this particular label for multi-directional reading results in using a supersquare = 1.75 inches diagonal where 0.25 inches must be added to allow for the speed of movement of the item.

The result is a 2 inch window size in the extended dimension.

The foregoing indicates that the minimum window size in the elongation direction is determined by the maximum label area to be read.

In addition to the foregoing, there are other reasons to limit the window elongation dimensions.

If it is desired to prevent multiple readings, i.e. it is possible to read several things on the window at the same time, two side-by-side There is a dimension that maintains the elongation dimension of the window smaller than the dimension of the small label.

The other extra half inch or so of space between the objects prevents the extension or depth dimensions from allowing multiple readings.

In summary, the electronic circuit can discriminate when scanning the length dimension without having to discriminate in the depth dimension.

This provides considerable simplification since scanning operations often read the same label over and over again.

Otherwise, it is difficult to distinguish between the label to be read and a second equivalent label passing through the window within the same field of view.

Another reason for making the window small in depth dimension is that it allows reverse directional viewing of the label synchronized to the scanning beam.

This allows operation of the system in bright light locations of the verification station and provides a good signal-to-noise ratio regardless of background light.

This means that the 2-inch depth dimension is approximately the same dimension that can be covered by most packaging;
This results from the fact that the packaging itself interrupts most of the reversible directional area of the window.

The fastest speed at which the collator moves the item across the reading window is about 100 inches per second, which is
Considering the maximum dimension of the C-label indicates that a depth dimension of approximately 2 inches is the minimum amount possible without unduly restricting other elements, particularly the decoding electronics.

Next, consideration of the human element is generally considered “front-on”.
leading to a desirable quality characterized as ``t-looking''.

When the verifier reaches for an item of merchandise and pulls it across the window, the verifier may orient the label symbol to face the depth dimension or direction of travel of the window as it passes. This is very possible.

If the label is on the side, this means that the vertically oriented label must be read.

In the case of many loosely wrapped items, such as 6-bag bottled items, it is not possible to tip the item as it passes through the window.

Therefore, if the bottom is not labeled, the reading mechanism must be able to read vertically oriented labels.

Although this is a human element issue, it cannot be ignored.

The reason is that the verifier looks at the package as it is lifted, notices where the label is placed, and passes it by the window with the label generally facing the depth dimension of the window. It is from.

Further packaging implementation considerations make side-labeled packages desirable, thus creating a need for encoded label reading systems to be able to read the sides of the package.

Previously proposed scanning procedures are unsuitable for scanning UPC label codes for one or other reasons.

A single X pattern has poorly shaped elements in the following points.

That is, when projected onto a vertically oriented label in a front-on sense, it tends to shrink and therefore only reads labels that are vertically oriented and can be read in a horizontal scan line.

Lissajous figure
Multiple X patterns, such as the group of es), suffer from the same difficulties, and additional difficulties in that the velocity of the laser movement caused by the generation of such figures is variable over a non-negligible range.

When combined with differences in label dimensions, this leads to widely varying raw data outputs that impose unacceptable high demands on the decoding and processing electronics.

The present invention anticipates the feasibility in which the limitations imposed by the foregoing analysis can be accommodated in a particular scan pattern.

This particular scanning pattern maintains a very low probability of non-reads, for example with a 3:1 ratio window area, and
On the other hand, it is possible to read labels oriented in any direction relative to the window and at a considerable distance to the wall of the product packaging.

The scan pattern of the present invention consists of a plurality of scan lines oriented across the depth dimension of the window and separated by occasional horizontal scan lines.

In particular, a scan cycle covering the entire window consists of a single horizontal scan line across the middle of the window followed by a group of vertical scan lines distributed across the window.

In each subcycle, the horizontal scan line repeats the same position, while the vertical scan line is shifted forward by a predetermined increment with respect to the previous subcycle until the entire window is covered by the vertical scan line. .

This pattern somewhat reveals lacing across the tear in the fabric, yet stitching over the cuts.

In addition to the foregoing, other limitations exist in scan speed and the nature of scans for read processing logic.

One of these is to get within relatively low cost LSI component technology, ie, within microsecond logic speeds.

As previously mentioned, the scan rate of the present invention is substantially uniform, so no changes occur in logic processing speed.

However, the scan rate for a 1 microsecond logic rate is approximately 8000 inches/second.

This speed is evaluated in terms of covering a 6 x 2 inch window with every imaginable type of pattern, and the optimal pattern emerges.

Thus, with velocity linearity and velocity constraints for relatively fixed values, processing logic and associated arithmetic may be used that are more easily processed and reduce the cost of the system.

The apparatus disclosed in the present invention for carrying out the foregoing procedure consists of a rather complex optical system.

However, the scanning element of this system consists of a single rotating part requiring only one moving part.

The system is therefore extremely simple in terms of mechanical operation.

More specifically, a plurality of mirror planes are mounted on the surface of a rotating surface that is rotated about its axis.

The orientation of each mirror element is such that a single horizontal raster line is scanned across the window, separated by a plurality of vertical lines formed by the combination of mirror elements.

Each of the vertical elements is a predetermined subcycle spaced across the window and successive subcycles that are incrementally shifted such that the window area is uniformly scanned by the vertical line by multiple subcycles. .

The horizontal scan line repeats each subcycle.

With appropriate alignment, a single laser beam is used to provide all vertical and horizontal scan lines.

The general object of the present invention is to provide a method and apparatus for reading coded labels of the aforementioned characteristics that have good frontal viewing characteristics, are reverse directional over a wide aperture, and are therefore not sensitive to ambient light conditions. It is in.

Another object of the invention is to provide a method and apparatus which has a high pattern efficiency and has the lowest scanning speed for the most efficient pattern, so that the scanning speed is approximately constant. be.

Another object of the invention is to provide a method and apparatus having a scanning pattern such that the average power during the reading window is maintained at a low level.

Another object of the invention is to provide a method and apparatus that allows a label to be read in all directions even if it is rotated while being passed through a reading window.

It is another object of the present invention to provide a method and apparatus having a depth of field in which codes that are displaced by several inches from the reading window can still be read.

Next, the present invention will be explained with reference to the drawings.

Referring first and specifically to FIGS. 1-5, the label reading apparatus of the present invention is shown including an end station or verification station 20. As shown in FIG.

Collation station 20 includes, for example, a conveyor belt 22 at 24 that conveys the articles toward the end of the station.

The conveyor belt is of any suitable type for conveying packaged items in the direction indicated by arrow 26.

A continuous conveyor belt is shown being passed around drum 28.

However, other types of conveyors may be used and, in fact, a conveyor system is not necessary if the conveyance of the goods is done by hand.

At the end of the station beyond the conveyor is an encoded label reader 32.

The reader includes a window 34 in its upper wall 36 through which the package is advanced, for example by a clerk performing the verification.

Preferably, it has a rectangular shape with a width to height ratio of approximately 1:3.

Movement through the window in the direction coincident with arrow 26 is herein defined as height movement or vertical movement, while movement transverse to the conveyor device is defined as width movement or horizontal movement. Defined as exercise.

As shown, the package to be processed is provided with a suitable line-type encoded label by any suitable means as known under the UPC specifications.

Obviously, the invention is particularly suited for use in reading UPC encoded labels, but other types of labels can also be read with suitable modifications.

The window passes a laser scanning beam 38 so as to impinge on the label 40 appearing on the item 30 through the window, as described below.

The window 34 also includes a reverse viewing hole for viewing spot reflections of the laser beam and passing changes back to the laser reading optics 42 as the laser beam scans the label on the package. ing.

The special configuration of the first embodiment of the device will now be described with reference to FIGS. 2-6.

It appears to be complicated due to the bending nature of the optical path.

A simplified schematic diagram will then be used to explain the operation of the device, which will make the invention easier to understand when the information to be given is taken.

With particular reference to FIGS. 2-6, the apparatus of the present invention includes a helium neon laser device 44 having a narrow beam 46 of approximately 2 milliwatts of power in the red region of the spectrum at 6328 angstroms.

The beam is sent through a rotating optic to a concave lens 48 which somewhat expands the beam.

After further passing through an optical device, the beam passes through a sub-raster mirror 52, as described below.
A convex focusing lens 50 is arranged so as to focus on a plane just beyond the window 34 through the lens.

After passing through convex lens 50, the beam is passed through a series of beam splitters 54, 56, 58 and mirrors 60.

The purpose is to generate three separate beams v1, V2 and v3 used for vertical scanning and one beam H used for horizontal scanning.

The three vertical beams are time-shared, and beam v1 is
It is responsive to a first set of eight lines forming a vertical scan pattern.

Beam V2 is associated with a second set of eight lines and beam V3
are associated with a third set of 8 lines to obtain 24 vertical lines in the scan pattern.

Horizontal beam H is associated only with horizontal scan lines, as described below.

Each of the movable mirror assembly vertical beams 1, v2, V3 and horizontal beam H are directed through various optics to impinge on the movable mirror assembly 60 one or more times, as described below.

Movable mirror assembly 60 includes a mirror ring 62 having an outer rim 64 that generally lies on a rotating surface in the shape of a frustocone supported about its axis 66 by a disk 68 and an axial shaft 70. .

The shaft member is coupled to a motor 72 to drive the shaft member once at a predetermined speed.

The periphery of rim 64 supports a plurality of flat mirrors 74-1 through 74-24 arranged at substantially respective angles as shown in FIG.

Therefore, each of the mirrors has a vector r1 passing through the axis of rotation.
form a surface with a vertical vector y that defines the angle of inclination of the mirror with respect to .

Each of the mirrors is numbered in the drawings and the following diagram indicates by number the raster and sub-raster tilt of each of the mirrors.

Since the tilt angle is with respect to a vertical vector rl centered through the axis of rotation of the movable mirror assembly, the surface of each mirror is slightly shifted between adjacent surfaces.

To avoid downtime due to gaps, the amount of overlap caused by this tilt is calculated and the mirrors are polished and held in place to give approximately an edge-to-edge relationship between each mirror. Preferably, the mirror is adjusted.

The following table gives the degree of tilt associated with each mirror.

The mirrors form an order in which horizontal mirror 1
, 4, 7, 10, 13, 16, 19 and 22, while the remaining mirrors are vertical mirrors.

As the assembly rotates, the topmost mirror is defined as raster mirror R, while it has moved two places counterclockwise (the two mirrors next to it are defined as sub-raster mirror SubR).

All of the horizontal mirrors have a tilt angle of 0°, while the vertical mirrors have varying degrees of tilt.

The disc member 66 of the gate structure mirror is provided with a plurality of holes 80-1 to 80-8, 24 in number, arranged together in groups of four and connected to each other. The hole count has been reduced to eight.

Both vertical and horizontal beams are passed through various parts of these holes, which when open act as pass gates for a particular beam and when closed act as stop gates.

Passage gates are V or H depending on the beam they pass
and the sign is given.

Horizontal Deflection System The horizontal beam is passed from the final mirror element 60 to a beam splitter which is a mirror and an aperture 80 used as a passage for the vertical beam.
−n is passed through the randomly placed part.

The horizontal beam is then redirected by a folding mirror 82 and passed through a portion of the same hole 80-n for the horizontal beam.

The length of the horizontal passage is approximately 1/3 of the circumference of the gate, which corresponds to the horizontal mirror taking up 1/3 of the circumference of the mirror assembly.

The horizontal beam is then redirected by a second folding mirror and passed through a beam recombiner 86 which transmits the horizontal beam.

The horizontal and vertical beams therefore travel in line through the relay lens system.

The relay lens system consists of a first lens 88 and an insertion lens 90 followed by an insertion and rerouting mirror 92.

The beam is incident on the top mirror of the mirror assembly, defined as raster mirror R, where it is reflected by that mirror to window or aperture mirror 94.

Aperture mirror 94 directs the beam through reading window 34 of the device.

Lenses 88 and 90 form a relay pair or combination such that any translational movement of the beam is converted into angular movement at mirror R.

This purpose will be discussed in more detail below in connection with the vertical deflection system.

As the movable mirror assembly rotates, the stationary horizontal beam is deflected along a horizontal path by the raster mirror.

The deflection magnification is controlled by the angle of incidence of the beam on the raster mirror.

In a particular embodiment of the invention, the arrangement is such that the mirror spacing is approximately 15 degrees and the horizontal sweep is approximately 6 inches at window 34.

Vertical Deflection System The vertical deflection system will now be described with reference to FIGS. 1-6 in conjunction with FIG.

As mentioned above, each vertical beam V1, v2, 3 is connected to a beam splitter 54, 56 as clearly shown in FIGS.
．． Formed in 58.

Each of the beam splitters deflects the beams by an amount such that the path lengths of beams 1, 2, and V3 are equal when redirected toward the movable mirror assembly.

This is done by deflecting the beam to a routing mirror behind the initial line of projection for beams V1 and v2, the amount of backward projection being determined by a beam splitter forming 58 points or beam v3 from that point on the drawing. This is the difference in distance.

The beam splitter has the following values:

That is, beam splitter 54, 25%, beam splitter 5
6.33-1/3% and beam splitter 58.50%.

From the subraster mirror SubR, the vertical beam is passed through a rerouting optics consisting of mirrors 96 and 98 through the vertical gate structure V of the assembly disk 68 to the beam recombiner 86 and to the relay lens. It passes through the assembly 88,90 to the raster mirror R, then to the aperture mirror 94 and through the window 34.

As mentioned above, the tilt angle of sub-raster mirror S ub R and the tilt angle of raster mirror R cancel the horizontal sweep and form a vertical sweep for each of the vertical beams.

Since the beam is angularly displaced in space at the beam splitter, the beam is angularly and spatially displaced at the reading window.

However, the magnification of this displacement affects not only the entire optical system but also the beams V1,v entering the sub-raster and raster mirrors.
2, varies depending on the incident angle of v3.

As shown somewhat more specifically in the simplified optical schematic diagram of FIG. It is constructed in such a way that the light of

The point is the point where the light has only angular movement on the raster surface.

In this way, the entire surface of the raster mirror can be used for the purpose of generating scan lines without the vertical scan extending beyond the edges of the raster mirror.

To separate the three vertical scan lines in time, these lines move through space as they reach the recombination optics.

By placing a suitably placed slit in this position it is possible to separate the vertical lines so that only one of them appears in the raster during each 5° portion of the 15° raster sweep.

Combined Operation of the Horizontal and Vertical Deflection System The results for the first eight sweep lines are shown in FIG.

As the rotating wheel advances to bring element T4-4 to the raster position, the eighth sweep line will be as shown in FIG.
Become horizontal again.

Thus, the first line is horizontal during the 15° passage of horizontal mirror γ4-1, while sweep line 2, 3.4 is formed by the combination of sub-raster mirror 74-4 and raster mirror 74-2.

After these lines pass, lines 5, 6. 7 is formed by a combination of a raster mirror 74-3 and a sub-raster mirror 74-5.

The tilt angle is adjusted such that sweep lines 5, 6 and 7 are shifted from initial sweep lines 2, 3 and 4 by a predetermined increment.

Mirror element 74-4 then becomes a raster mirror and the next horizontal sweep (number 8) occurs.

This represents a subcycle. The next subcycle, beginning with horizontal sweep 8, proceeds with two sets of vertical sweeps shifted again by other predetermined increments by the adjusted tilt angle of the movable mirror assembly until each subcycle is completed.

At the end of the four subcycles, 24 vertical scan lines are formed across the surface and are progressively shifted from the initial scan line.

Because of the geometry chosen for this particular window, the vertical scan lines are divided into three groups and begin at uniformly spaced locations across the window plane.

Within each subcycle, there is one horizontal scan line.

The complete scan formed by the rotation of mirror ring 1 and 2 is the first
0, each scan being appropriately labeled 1-24.

Using one rotating mechanism to form orthogonal (in this case vertical and horizontal) scan patterns allows the formation of one scan direction tangential from one element (in this case the horizontal scan formed by the raster mirror) and It relies on the formation of a tangential scan from a second element (sub-raster) which is reimaged by an optical train that may or may not contain raster elements.

The advantage of using raster elements is twofold. That is (1)
(2) being able to obtain a spatially compact inverted observation and acquisition system; and (2) a source of virtual coincidence of the two scans so that the patterns are projected dimensionally coincident.

Reimaging the sub-raster scan onto the raster scanning element has several purposes.

(1) Rotation of the sub-raster scan to perform addition and subtraction of raster and sub-raster scan vectors for the composite scan direction; (2) Facilitating the combination of vectors in (1) above. (3) conversion of the sub-raster scan image into a point image in the raster element to improve the duty cycle (du', y cycle), etc.

In special cases, the scanning pattern is used for reading2
It has two nominal projection planes, namely the plane of the window and the side of the package with the indicia on the side facing the direction of package movement.

In these two reading planes, the point scanning speed is 80
Uniformly and linearly equal to the nominal design speed of 0 0 ips.

For these conditions, the vertical scan rate in projection perpendicular to the beam direction is equal to 6 1 2 8 ips.

This consideration is determined entirely by constraints in the display or level viewing area.

The generation of a vertical scan rate of 6 1 2 8 ips while maintaining a horizontal scan rate of 8000 ips, projecting uniformly in all relevant directions, determines the vector combination criterion in the raster scan rate.

6 1 from an element generating 8000 ips horizontal scanning component
Generating a 28 ips vertical scan is 100 ips oriented at 127°27' with respect to the horizontal scan component.
Requires 76 ips sub-raster scan component.

Next, the role of the relay imaging system will be explained.

The sub-raster element (since its angular scanning velocity is tightly coupled to the raster scanning velocity) is approximately 8 0 0 0
Forming the IPS scan size.

This sub-raster scanning speed of 8000 ips is achieved by the relay lens element in the raster element image plane.
Expanded to 0 0 7 6 ips.

The enlarged sub-raster scan image is rotated by the relay mirror to a defined angle of 127° 27' with respect to the raster scan direction.

Finally, the relay lens (projected 1 0 0 7 6
Convert the IPS enlarged sub-raster scan to a point image with an angular scan component.

Advancement of the vertically scanned image across the dimension of the pattern is done in two steps.

Step 1 is to spatially position the three vertical scans 5° apart using a 15° raster angular rotation.

Step 1 is done independently as each raster element rotates through its effective hole.

Step 2 sequentially displaces the positions of the three vertical scan sets formed in step 1 by 5/8° to generate eight sets evenly spaced over 5° space between scans within each set. It is to be.

Step 2 is done by tilting the (combined) raster and sub-raster elements with respect to the nominal tangential (surface normal vector aligned with the radial vector through the axis) cardinal direction.

A table providing suitable tilt angles for the particular devices disclosed herein is provided below.

Accordingly, FIG. 10 shows the completed scan, with each line numbered (1-24), each 0. It appears as a pattern similar to a stitch, with 24 vertical scans of 25 ms and 4 horizontal scans of 0.75 ms each.

The order is numerically horizontal, six vertical, forming each subcycle 1-7, 1-14.15-21.22-28.

The mirror assembly includes 24 facets, 12 of which represent one complete cycle.

3 4 as it forms the raster trace speed
Rotates at 00 rpm.

To further explain the optical characteristics of the system, the relay optics have field stops that limit the eccentric motion of the beam that would otherwise become a vertical beam.

The edges of the field stop are adjusted so that the vertical beam emerging from the window at the top of the scanner appears to turn on and off automatically at precisely the appropriate times.

Further, the sub-raster and the relay optical system at one raster point can be considered as the entrance and exit of the relay optical system.

The concave and convex lens combination 48,50 is separated by a distance so that the light beam coming from the laser is focused to a point image in the field stop of the relay optics.

The injection lens relays that image and forms a new image of that image at a plane 103 at the top of the window or at a point beyond the top.

Inverted Directional Observation System (Collection Optics) Referring to FIGS. 1-5 in conjunction with FIG. 9, the inverted directional observation system of the present invention is shown, which includes an aperture mirror 94. FIG.

The mirror 94 transmits the entire hole of the observation window downwardly to the raster mirror R, and upwardly to the routing mirror 100, through the focusing lens 102, to the photomultiplier tube.
e) It reaches 1 0 4.

The aperture of the inverted observation optics is such that a complete field of view of the aperture 34 is possible.

However, the movement of the raster mirror is directional with respect to the horizontal scan, so the horizontal scan line appears as a fixed position in the optical multiplex.

By limiting the movement to one direction, the choice and structure of the optical multiplex tube is a straight, standard side cathode tube,
That's quite satisfying.

Reversing directional lens 102 is an aspheric lens corrected for spherical aberration and coma, thereby providing a clearly focused scan line image to scan plane 103.

A narrow band spectral filter 105 is placed in the image of the system of lines at the top, which is optimized for a cone of light to be focused there.

In line with that, there are so-called spatial filters, which are small rectangular slots that limit the amount of light.

You want the light to be collected from the area at the top of the restricted window,
In other words, it is used more in the part of the scan where it is desired to eliminate background light more efficiently.

Further describing the collection optics, a raster mirror on a rotating ring is the main component of this part of the system.

The raster mirror is separated from the collecting lens by approximately the focal length.

This automatically makes the collection system a long-range centric collection system and allows optimal utilization of spectral filters with angular transmission dependence of the incoming light.

With far-field centrality, a constant angle of the incoming light is maintained across the field of view of the scanning system, thereby providing optimal specifications on the transmission properties of the spectral filter.

Referring now to FIGS. 11 and 14, a second embodiment of the present invention is shown, which uses a relatively simplified optical system made possible by utilizing a different type of gate system. ing.

However, simplifications have been made in the routing optics rather than in the active optics themselves, so that the optical description of the schematic diagram of FIG.
Equally applicable to figures.

Therefore, the description in this regard has been simplified considerably, and similar parts have been designated by the same numbers with an added dash (').

A laser 44' is provided, the output of which is passed through a concave lens 48' and a convex lens 50', the output of which is passed through a beam splitter 54', 56', 58' to give three vertical beams v1, V2, v3. The paths are defined and have equal optical path lengths as described above.

A fourth horizontal beam H is provided by reflective element 60' and is routed by element 110 and directed to the raster surface of the top mirror.

The motion of the horizontal scanning vector H is best illustrated in FIG.

The vertical scan vector is redirected via mirror 112 to subraster surface SubR and then to beam combiner 86'.
, lens 88', projection mirror 92' and projection lens 90'.
through to the raster surface.

The motion of the output vertical beam is best shown in FIG.

FIG. 14 is an enlarged view of the view shown in FIG. 11, showing the nature of the surface.

The surface is provided with three channels, the first,
The subraster miso is at the top and is contacted by the vertical beam on the subraster mirror.

A vertical raster channel is spaced through each horizontal raster mirror, and a horizontal raster groove is spaced the distance of each scan of the vertical raster mirror.

Since the beam is slightly displaced, particularly as shown in FIG. 11, the various vertical or horizontal blanking characteristics pre-provided by the gating mechanism shown in FIG. Blanking is provided by directly performing a masking technique.

As previously mentioned, the operation of the embodiments of FIGS. 12 and 14 is the same as described above.

Many variations and modifications can be made within the scope of the invention by those skilled in the art.

Here, different gating means have considerably simplified the device.

A special object of the invention is to provide a predetermined hypersquareness condition (overs) for the display area as an example of the specification of the geometric shape.
U with quareness condition)
It was to read the PC symbol (UPC display).

A display area is one of several areas of the display that must be completely read in one scan in order to be decoded without maintaining sufficient noise discrimination.

The hypersquareness of the regions is determined by the difference in height and width of the regions, and a rectangular scan vector is used to allow omnidirectionality of the display.

The dimensions of the supersquare determine the scan repetition rate (cycle time) for scans oriented perpendicular to the display speed direction.

At the same time, hypersquareness determines the spatial overlap required for scan segments oriented parallel to the display speed direction.

In the particular case of the invention, the pattern is as follows:
Determined by display specifications.

(1) Rectangular scan (90° angle redundancy) (2) 2.25 ms between repeated horizontal scans (time redundancy) to allow vertical display speed of 100 ips (3) Incremental vertical scan Adjacent vertical scan spaces with a shift of 0.224 inches (temporal redundancy) Other possibilities also exist.

For example, if it is desired to choose a rectangular window with a width to length ratio of 1:2, the device described herein can be adapted to such an application and eliminates the need for one vertical beam. Can be erased.

A double vertical scan through each subcycle is adequate to occupy the relevant space.

Also, the sub-raster mirror is rotationally displaced from the raster mirror by two mirrors, and the sub-raster mirror is . It is equally possible to place it in any position of the ring.

[Brief explanation of drawings]

1 to 10 relate to a first embodiment of the invention, while FIGS. 11 to 14 relate to a second embodiment. Note that FIGS. 1, 5, 6, and 10 are common to each embodiment. FIG. 1 is an elevational view of a laser level reader constructed in accordance with the present invention. FIG. 2 is a top view of the label reader of FIG. 1 taken along line 2-2. FIG. 3 is a top view of the label reader of FIG. 2 taken along line 3--3. FIG. 4 is a top view of the label reader of FIG. 2 taken along line 4--4. FIG. 5 is a top view of the label reader of FIG. 1 taken along line 5--5. FIG. 7 is a simplified schematic diagram similar to FIG. 3 showing the label reader of FIG. 1 emphasizing each component of operation during a horizontal scan. FIG. 8 is a simplified schematic diagram similar to FIG. 3 showing the label reader of FIG. 1 emphasizing each component of operation during vertical scanning. FIG. 9 is a simplified schematic diagram similar to FIG. 3 highlighting and illustrating each component used in reversible viewing of packaging labels. FIG. 10 is a diagram of a test pattern generated by the apparatus of FIGS. 1-9. FIG. 11 is a plan view showing a second embodiment of a label reader constructed in accordance with the present invention. FIG. 12 is a front elevational view taken from line 12-12 of FIG. 13 is a side elevation view taken from line 13--13 of FIG. 11. FIG. Figure 14 shows the first
14 is a diagram of a masking pattern used in the mirror ring of the apparatus of FIGS. 1-13; FIG. 20... Collation station, 22... Conveyor belt, 28... Drum, 30... Product, 32... Encoded label reader, 34... Window, 36... Top wall,
40... Label, 42... Laser reading optical device.

Claims (1)

Claims: 1. A method of reading a coded label on an article through a window forming a short vertical dimension in the direction of movement of the article and a long horizontal dimension transverse to said direction of movement, comprising: generating a laser beam and performing a horizontal scanning; moving the beam sequentially in a pattern consisting of a plurality of vertical scans interspersed with each other, the horizontal scans being stationary with respect to the window, and the vertical scans increasing in predetermined increments until the window area is covered by the vertical scans; scanning the horizontal path of the beam in a reverse direction to receive a change in reflection from the label and forming an electrical signal indicative of the change in reflection. Method. 2. An apparatus for reading machine-readable coded labels on articles at a verification station, comprising window means associated with said verification station, means for supporting said article for movement through said window means, and an output beam. Laser source and multiple vertical beams with predetermined angular divergence■
1, V2, V3 O and a horizontal beam H, a scanning optical system comprising a mirror ring having a plurality of mirrors thereon, a raster position, a sub-raster position, and an input for receiving. and a relay optical system for projecting the raster position on the horizontal beam, wherein the horizontal beam is scanned in a horizontal angle by the movement of the mirror ring and converted into the horizontal movement of the H scan line, and the horizontal beam is converted into a horizontal movement of the H scan line, and to said sub-raster positions, said relay optical system means having an input for receiving and projecting said vertical beams V1, v2, v3 to said sub-raster positions, said relay optical system means transmitting a composite vertical component to said sub-raster positions; serves to convert the movement of the mirror wheel at the sub-raster position into a vector that adds while canceling the horizontal scan vector component at the raster position and transforms the sub-raster into a point image with a purely angular scan component at the raster position. gating means serving to convert the composite and allowing only one of said beams V1, V, V3M H to pass through the device; and an inverter receiving light reflected from the area of impact of said beams on the label. An apparatus further comprising directional observation means and means for converting the reflected light into an electrical signal indicative of its intensity.