INSTANT PORTABLE BAR CODE READER
CROSS-REFERENCE TO RELATED
This is a division of our prior application U.S. Ser. No. 637,693 filed Aug. 6, 1984, now U.S. Pat. No. 4,570,057 on Feb. 11, 1986. Said application Ser. No. 637,693 is in turn a continuation of our earlier application Ser. No. 334,811 filed Dec. 28, 1981, now aban- 10 doned.
BACKGROUND OF THE INVENTION
The present application is particularly directed to improvements in the invention of our U.S. Pat. No. 15 4,282,425 issued Aug. 4, 1981. The disclosure of said patent is incorporated herein by reference, particularly for purposes of background information.
SUMMARY OF THE INVENTION 20
The present invention, in one important aspect, is directed to the provision of a particularly facile and effective hand held reader unit for the instantaneous reading of complete bar code patterns of curved or irregular configuration, and comprising an optical sys- 25 tem which accomodates itself to a compact and rugged, yet lightweight construction capable of economical manufacture.
In another aspect, the invention provides a high speed bar code reader system and method which is 30 capable of reading a complete bar code pattern as an entity for computer processing without requiring the reader unit to be moved during the read-in operation; such system and method being further optimized by the provision of a flash illuminator of special configuration 35 for providing a particularly uniform obliquely directed light output over the full depth of the optical field of the reader lens system, and by the provision of a lens system which is adjusted in its spectral response and stop aperture characteristics so as to achieve a high resolution 40 and accuracy over a sufficient depth of field to read high density bar patterns with marked curvature or surface irregularity.
It is therefore an important object of the invention to provide a portable instant bar code reader and method 45 providing improved optical characteristics.
Another object resides in the provision of a bar code reader system and method exhibiting an improved flash type illuminator.
It is also an object of the invention to provide a porta- 50 ble instant bar code reader system and method wherein the optical and electronic construction are interrelated so as to provide for quck-repeat, more accurately focussed reading where an initial reading is ineffective because of marginal reading conditions or the like. 55
Still another object resides in the provision of a hand held bar code scanner having novel electronic, optical and structural features adapted to the implementation of the various objects set forth above.
Features of the invention include the provision of a 60 reader unit with a wide field of view and substantial focal depth, which yet has a narrow hand grip configuration, and a compact optical system; and optics system which accomodates a single unitary circuit board configuration, a rigid lens mounting arrangement which 65 furthers the achievement of a precise and reliable optical system with a dust and moisture proof enclosure and substantial impact resistance; and an optical system
providing an optical field of extended depth coupled with an optimum focus at a selected close up position and electronics for signalling an inaccurate reading and automaticaly repeating the read operation if necessary as the operator adjusts the unit toward the optimum reading position until a valid reading is achieved.
These and other features, objects and advantages of the present invention will be understood in greater detail from the drawings and the following description wherein reference numerals are applied to a preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a somewhat diagrammatic perspective view illustrating a hand-held reader unit and associated components in operative reading association with a bar code pattern on a container;
FIG. 2 is a somewhat diagrammatic longitudinal sectional view showing the general layout and configuration of the reader unit of FIG. 1;
FIG. 3 is a somewhat diagrammatic plan view of the reader unit of FIG. 2 with a top casing part removed and internal components diagrammatically indicated;
FIG. 4 is an enlarged partial somewhat diagrammatic view of the reader unit of FIG. 3, the section of FIG. 4 being taken along the lines IV—IV of FIG. 3;
FIG. 5 is a somewhat diagrammatic, cross-sectional view taken along the line V—V of FIG. 4;
FIG. 6 is a somewhat diagrammatic, cross-sectional view taken along the line VI—VI in FIG. 4;
FIG. 7 is a diagrammatic illustration showing exemplary details of a suitable electric circuit configuration for the system of FIGS. 1 through 6;
FIG. 8 is a somewhat diagrammatic view illustrating the basic optics of the illustrated embodiment and showing the lens arrangement generally in the plane of FIG. 3;
FIG. 9 is a plot illustrating lateral aberrations for the system of FIGS. 1 through 8;
FIGS. 10 and 11 show optical transfer functions for the system of FIGS. 1 through 9, FIG. 10 being for the "Through Focus" condition and FIG. 11 being for the "Best Focus" condition;
FIGS. 12, 13 and 14 illustrate radial distortion, geometrical astigmatism, and MTF astigmatism, respectively, for the system of FIGS. 1 through 11; and
FIGS. 15 and 16 together provide a diagrammatic showing of the electric circuitry for the interface component 17, FIG. 1, where the unit 16 is itself battery operated and portable.
Referring to FIG. 1 there is illustrated an overall bar code reader system in accordance with the present invention, and showing a hand-held reader unit 10 in scanning relation to a bar code pattern 11 associated with a product container 12. By way of example, the bar pattern 11 may be formed in accordance with the universal product code and may have a length of 65 millimeters. Various other bar code types are known in the art, such as EAN, CODBAR, CODE 39, INTERLEAVED 2/5, etc.
The hand-held unit is shown as comprising a case 14 including a portion 14a of a size to be gripped by the user, a head portion 146 for containing the reading optics and a connecting portion 14c integrally connecting the hand-grip portion 14a with the optical reading