| 1. | An optical character scanning apparatus for reading a strip of visual indicia located along the face of a document, comprising: a support frame having a stationary wall surface area adapted to be slidably engaged by the document face; a viewing slot formed through the frame in open communication with said wall surface area; an array of lightresponsive sensors mounted to said frame; lens means mounted to said frame intermediate the viewing slot and the array of lightresponsive sensors for focusing light reflected through the viewing slot onto the array of lightresponsive sensors; and means for fixedly mounting the frame to a docu ment guiding apparatus, whereby optical alignment of the viewing slot, array of lightresponsive sensors and lens means may be accomplished on the frame prior to such mounting. |
| 2. | An apparatus as set out in claim 1 further comprising: light means on said frame for directing light onto the face of a document within the field of the viewing slot as the face of the document is slidably engaged by the stationary wall surface. |
| 3. | An apparatus as set out in claim 1 further comprising: a mirrored surface on said frame facing toward the viewing slot at a 45° angle; said lens means and array of lightresponsive sen¬ sors being arranged on said frame at a 45° angle relative to the mirrored surface and along a line parallel to said stationary wall surface area. |
| 4. | An apparatus for reading a longitudinal strip of visual indicia containing discrete alphanumeric characters located along the face of a document, wherein the document has a constant thickness and its face is bounded along one side by a planar longitudinal reference edge, the document having a predetermined width dimension perpendicular to the reference edge, the strip of visual indicia being located within transversely spaced bound¬ aries parallel to one another and to the reference edge of the document; a rigid frame; an elongated document slot formed through the length of the frame; said document slot being bounded by a pair of op posed walls having inner surfaces faced apart to freely receive the thickness of a document between them, said walls having coplanar longitudinal edges and outer ends; said document slot also being bounded by a base that extends between said pair of walls at a location spaced inwardly from the longitudinal edges thereof a distance less than the document height; whereby the document can be manually moved in a longitudinal direction within the document slot with respect to the frame, the document being handheld and guided by sliding engagement of the base by the refer¬ ence edge of the document; a separable support frame having a stationary wall surface area adapted to be slidably engaged by the docu¬ ment face; a viewing slot formed through the support frame in open communication with said wall surface area; an array of lightresponsive sensors mounted to said support frame; lens means mounted to said support frame inter¬ mediate the viewing slot and the array of lightrespon¬ sive sensors for focusing light reflected through the viewing slot onto the array of light responsive sensors; one of said walls of said rigid frame having an opening formed therein to receive the stationary wall surface area of the support frame in a position at which it is substantially coplanar to the inner surface of said one wall; and means for fixably mounting the support frame to said one wall, whereby optical alignment of the view¬ ing slot, array of lightresponsive sensors and lens means can be accomplished on the support frame prior to such mounting. |
| 5. | An apparatus as set out in claim 4 wherein the opening formed through said one wall of the rigid frame is located between the base of the document slot and the longitudinal edges of the walls on said first frame, the distance between the base and the opening corresponding to the separation between the reference edge of a docu¬ ment and the strip of visual indicia. |
| 6. | An apparatus as set out in claim 4 further comprising: light means on said support frame for directing light onto the face of a document within the field of the viewing slot as the face of the document is slidably en gaged by the stationary wall surface. |
| 7. | An apparatus as set out in claim 4 further comprising: a mirrored surface on said support frame facing toward the viewing slot at a 45° angle; said lens means and array of lightresponsive sen¬ sors being arranged on said support frame at a 45° angle relative to the mirrored surface and along a line paral¬ lel to said stationary wall surface area. 'ΞE. |
Optical Character Scanner
Technical Field
This invention relates to a separable scanning ap- paratus designed to be incorporated within document guide and recognition equipment for reading of alpha-numeric characters appearing on the face of a document.
Background Art Optical scanning of alpha-numeric characters by use of a transverse scan line to detect light and dark reflective light patterns requires extreme precision in the alignment and focusing of light from the scan line to the receiving light-responsive sensors. Such align- ment becomes even more difficult with miniaturization of such equipment in conjunction with the production of com¬ pact, economical peripherals. Alignment is also an im¬ portant factor in servicing of such equipment, since field alignment at the site of the user is impractical where lamps, lenses or light-responsive sensors might have to be replaced.
Disclosure of Invention
The present invention constitutes a separable sup- port frame having a surface that is slidably engageable by the document face. A viewing slot is formed through the support frame in communication with the stationary wall surface area. Lenses mounted on the frame focus light reflected through the viewing slot onto light re- sponsive sensors. The apparatus is a self-contained
optical scanner, whose components can be prealigned prior to assembly of the support frame within the recognition equipment.
This disclosure relates to an assembly of charac- ter scanning components on a separable subframe or sup¬ port frame which can be fixedly mounted to a document guiding apparatus or other optical character recognition equipment. The support frame includes a stationary wall surface area adapted to be slidably engaged by the docu- ment face. By mounting the components of the character scanning apparatus on this unitary frame, all of the components can be aligned when assembled. A complete aligned assembly can be initially installed in the op¬ tical character reader when it is constructed and can be replaced as a pre-aligned unit for servicing purposes. Such replacement will minimize service and repair time and assures that repaired equipment will meet original alignment specifications.
Brief Description of Drawings
Fig. 1 is a perspective view of the apparatus, il¬ lustrating its use;
Fig. 2 is a fragmentary plan view of the apparatus; Fig. 3 is a sectional view taken along line 3-3 in Fig. 2;
Fig. 4 is a sectional view taken along line 4-4 in Fig. 2;
Fig. 5 is an exploded view of the document slot and character scanning assembly; Fig. 6 is an enlarged plan view of the character scanning assembly;
Fig. 7 is a corresponding elevation view; Fig. 8 is an enlarged sectional view taken along line 8-8 in Fig. 7; Fig. 9 is a sectional view taken along line 9-9 in Fig. 8; and
Fig. 10 is a sectional view taken along line 10-10
in Fig . 8 .
Best Mode for Carrying Out the Invention
The present disclosure relates to a compact, man- ually fed optical character recognition device in which documents are moved along a slot for reading purposes. It is designed for reading a longitudinal strip of visual indicia 11 containing discrete alpha-numeric characters located along the face 12 of a document 10. The document 10 illustrated in Fig. 1 is a conventional check blank used for commercial banking purposes and having a printed line of machine readable information that typically identifies the bank, the user's account, and the amount of the check. The document 10 has a constant thickness and can be made from a sheet of paper, paperboard, plastic or other suitable sheet material. Its face 12 is bounded along one side by a planar longitudinal reference edge 13, which in this illustration constitutes the bottom edge of the rectangular check blank. Document 10 has a pre¬ determined width dimension in a direction perpendicular to the reference edge 13. This width dimension would be measured across the end edges 14 which extend between the reference edge 13 and the remaining longitudinal edge 15 presented along the top of the check blank.
A strip of visual indicia 11 is located on the face 12 within transversely spaced boundaries that are paral¬ lel to one another and are also parallel to the lower reference edge 13 of document 10. In this illustration, these boundaries are coincident with the upper and lower edges of the alpha-numeric characters imprinted on the check blank.
As a general definition of the document geometry pertinent to this disclosure, the strip of visual indicia will have a transverse width perpendicular to the docu¬ ment reference edge and will be arranged parallel to said edge.
The present apparatus is provided within an en¬ closure generally designated at 16. The enclosure 16 has outer surfaces including an upper longitudinal wall surface 17, a front wall surface 18, a rear wall surface 20 and oppositely facing end wall surface 21. The en¬ closure 16 as illustrated is rectangular in shape, and contains all the interior components of the apparatus in the completed assembly (Figs. 1 through 4) .
The upper wall surface 17 and end wall surfaces 21 0 are interrupted by a longitudinal document slot 22. Slot 22 intersects the walls on which these surfaces are formed and which extends the full length of enclosure 16. Slot 22 is a document guiding apparatus by which individ¬ ual documents 10 can be fed longitudinally the length of -5 the enclosure 16 to permit machine reading of the strip of visual indicia 11.
Located within enclosure 16 is a rigid frame gen¬ erally shown at 33. The frame 33 includes the stationary support elements for the various components of the appa- 0 ratus. It includes upwardly protruding front and back longitudinal walls 23, 24 which are located in close op¬ posed positions. The walls 23, 24 have respective op¬ posed inner surfaces 25, 26 spaced apart transversely by a distance adequate to receive the thickness of a 5 document 10 between them. They include coplanar longi¬ tudinal upper edges 28, 30 and coplanar outer ends 31, 32, respectively. A base 27 extending between the inner surfaces 25, 26 of the two walls 23, 24 completes the boundaries of document slot 22. Base 27 is positioned 0 at a location spaced inwardly from the longitudinal up¬ per edges 28, 30 of walls 23, 24 a distance less than the height across the document 10. The upper edges 28, 30 are located in close proximity to the upper longi¬ tudinal wall surface 17 of enclosure 16. The slot depth *-** is such that a document 10 can be manually moved within it in a longitudinal direction with respect to the rigid frame 33 and enclosure 16. Document 10 is hand-held and
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guided along slot 22 by sliding engagement of base 27 by the document reference edge 13. This general operation is illustrated in the view shown in Fig. 1.
To facilitate entry of document 10 within document slot 22 from either end of enclosure 16, the outer ends of slot 22 are formed by inwardly converging surfaces 34,
35 formed at the respective longitudinal ends of the- front and back walls 23, 24. The slot access openings presented by the exterior wall surfaces 17 and 21 of en- closure 16 are correspondingly tapered in shape (Fig. 1) . However, the operational section of slot 22 intermediate its ends is formed with the inner surfaces 25, 26 of the front and back walls 23, 24 parallel to one another and spaced apart a distance slightly greater than the thick- ness of the document 10 designed to be fed between them. The general assembly of the apparatus essentially comprises character scanning means 36 mounted to the frame 33 and located within enclosure 16 for electron¬ ically generating images of each alpha-numeric character. As will be described below, the character scanning means
36 is mounted on a separable support frame 37 that is detachably fixed to and forms part of rigid frame 33. The electronic components of the character scanning means 36 are located on a printed circuit board 58 fixed alongside front wall 23 (Fig. 3) .
The apparatus is completed by electronic recogni¬ tion processing means located on the rigid frame 33 and also positioned within an enclosure 16. The recognition processing means 38 is operatively connected to the character scanning means 36 for analyzing the electronic images generated thereby and for encoding the images into a machine readable code. It provides- the final coded information at output terminals 40 adapted to be wired to the Host Processor (not shown) . The recognition processing means is located on a printed circuit board 41 rigidly secured . to end support brackets 42, which in turn also mount the slot structure
presented by walls 23, 24 and base 27. The electronic components of the character scanning means 36 on circuit board 58 are connected to components on the board 41 through ribbon conductors 60, 61 arranged between the two upright boards. While the precise arrangement of the electronic components is not critical to an understand¬ ing of this invention, it is to be noted that all elec¬ tronic components of the reader assembly are fully con¬ tained within the compact enclosure 16. As an example of the practical application of this equipment, the illustrated apparatus might read a - printed strip of visual indicia 11 on the face ' of a check blank and be utilized by bank tellers to verify the status of a customer's account by access to informa- tion stored in a central computer memory. It might be similarly used by personnel in sales establishments to verify the status of a checking account balance before accepting or cashing the check written on the face 12 of the document 10. The details of the character scanning means 36 are best illustrated in Figs. 5 through 10. The character scanning means 36 is mounted to the upright wall 43 and protruding shelf 44 of the separable support frame 37 as a subassembly which permits prealignment of the physical components of the scanning means prior to assembly on the remaining elements of the rigid frame 33. This also permits these components to be pre-aligned and readily replaced as a unit for servicing purposes.
The support frame 37 includes a stationary wall surface area 45 (Fig. 10) which is adapted to be slidably engaged by the document face 12. The section of upright wall 43 about area 45 serves as a document viewing as¬ sembly for reflecting light from the strip of visual in¬ dicia 11 on document 10. The details of this assembly are shown in Figs. 8-10.
The front wall 23 along the open slot 22 has a- complementary opening at 46 to receive the wall surface
area 45 of the frame 37 in a position at which the sur¬ face area 45 is substantially coplanar to the inner sur¬ face 25. To assure sliding engagement of the document face 12, it is preferable that the area 45 be slightly radiused and protrude very slightly beyond surface 25 and extend within the confines of slot 22.
The opening 46 is located elevationally between the slot base 27 and the longitudinal edges 28, 30 of the walls 23, 24. The distance between base 27 and the mounted wall surface area 45 corresponds to the trans- verse separation between the lower reference edge 13 of document 10 and the strip of visual indicia 11. Thus, the moving strip of visual indicia 11 will overlap the stationary area 45 as the document 10 traverses the length of slot 22.
Light means is provided on the frame 37 for direct¬ ing light onto the face 12 of a document 10 across the moving path of the strip of visual indicia 11. This light means is illustrated as four incandescent lamps 47 mounted to the back of printed circuit board 58 and re¬ cessed within the upright wall 43 immediately outward from the wall surface area 45 (Fig. 8) . The light means also includes upright light guide slots 48 which con¬ verge toward one another from the lamps 47 and openly intersect the critical wall surface area 45.
Light sensing means 50 is mounted to shelf 44 of frame 37 for producing analog signals at individual ter¬ minals proportional to the level of light intensity directed to them. Means 50 in general comprises an array or matrix of light-responsive sensors for detecting the geometric relationship of light values directed upon it. The unit illustrated is a conventional self-scanning linear photodiode Array which consists of a single ver¬ tical row of silicon photodiodes. The individual output terminals are shown as a bundle of conductors 51 leading to a receptacle 52 at one end of wall 23 (Fig. 3) , which in turn is wired to the proper components on the printed
circuit board 41.
Optical viewing means is used between the light means and array 50 to direct reflected light from the face of document 10 to the array of photodiodes. The optical viewing means includes a narrow vertical viewing slot 53 that centrally intersects the two light guide slots 48 at a plane slightly recessed from the wall sur¬ face area 45 (Fig. 8) . The width of the knife edge slot
53 is sufficiently narrow to have an aperture function in assuring viewing depth of field through it across the permissible planar locations in which the face 12 of a document 10 might be viewed within document slot 22. The narrow field viewable through the viewing slot 53 con¬ stitutes a scan line which is physically positioned with respect to document slot 22 so as to traverse the strip of visual indicia 11. The. side edges of slot 53 formed through the upright wall 43 of subframe 37 converge out¬ wardly to permit maximum' reflectance of light through the thickness of the upright wall 43. The light path, which is initially perpendicular to the wall surface area 45, is turned 90° by the reflective surface of a mirror
54 mounted at an angle of 45° across shelf 44, and is beamed to focusing lenses 55, 56 arranged along shelf 44 to properly direct the reflected light patterns from slot 53 onto the photodiodes of the Array 50. The lenses 55, 56 and Array 50 are aligned parallel to the wall sur¬ face area 45.
Since the separable frame 37 contains the surface area 45 which the field viewable through slot 53 must engage, the entire optical path from document 10 to
Array 50 can be prealigned on frame 37 independently of the remaining components of the reader. This is much less cumbersome than the alternative of aligning the components on the total assembly and eliminates align- ment of individual elements when servicing the equip¬ ment. Frame 37 is fixed as part of rigid frame 33 by releasable screws 39 (Fig. 3) .
Referring now to Figs. 8, 9 and 10, the wall sur¬ face area 45 includes provision for dispersal of environ¬ mental dust and solid particles that might otherwise col¬ lect about the area of the viewing slot 53 as documents 10 are fed past it, particularly when the documents are made from paper or paperboard. To minimize the diffi¬ culties that are encountered due to dust, upright venti¬ lation ducts 57 are formed within the upright wall 43 and surround the lamps 47. They openly intersect the light guide slots 48. As discussed previously, lamps 47 are preferably of the incandescent type, but might be any suitable heat emitting light source.
The ventilation ducts 57 provide convection cool¬ ing of the lamps 47 or other light means and dispersion of environmental dust in the vicinity of the viewing slot 53. Each duct 57 extends through the height of the up¬ right wall 43 within the subframe 37 (Fig. 9) and has open communication in frame 33 beyond the boundaries of the upright wall 43 at positions above and below the width of slot 53. The lower end of each duct 57 is open and unobstructed in the completed assembly. Ventilation of the upper end is assured through open communication along mating duct extensions 59 in wall 23 (Figs. 3,5). As can be seen in Fig. 9, ducts 57 are preferably cylindrical apertures formed parallel to one another and extending through the full height of wall 43. Ducts 57 are in open communication with the complete height of each light guide slot 48. Upright movement of air within ducts 57 will tend to also draw air (and small dust or solid particles) from the edges of the viewing slot 53. The moving currents of air will tend to disperse this dust outside the viewing slot area, where it can come to rest on horizontal surfaces within the enclosure 16 not critical to the optical path of the character scanning means.
The reader is also provided with two control sen¬ sors 70, 71 that are physically mounted on wall 23 at
opposite sides of the viewing slot 53 (Fig. 5) . They enable the recognition processing means 38 to identify the direction of travel of each document 10 moved through the slot 22.
Various modifications might be made with respect to specific electronic components of this invention. The functional attributes of these components are therefore the only details believed to be essential to an under¬ standing of the invention disclosure.