Scanning module for single line and raster scanning using dual lasers

• US 20030047614A1
• Filed: 07/12/2002
• Published: 03/13/2003
• Est. Priority Date: 03/26/1998
• Status: Active Grant

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Bhargava, Vikram, Barkan, Edward, Austin, Timothy, Dvorkis, Paul, Grosfeld, Henry
• Granted Patent: US 6,712,274 B2
• Time in Patent Office: Days
• US Class Current: 235/462.37
• CPC Class Codes: G06K 7/10594 Beam path
• CPC Class Codes: G06K 7/10653 using flexible or piezoelectric means
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/1098 the scanning arrangement having a modular construction

Abstract

A retroreflective optical scan module, including first and second selectable light sources having different beam characteristics for directing a selected light beam to a symbol to be read, an optical assembly including a light collecting portion which collects and redirects the light reflected from the symbol along an optical path to a sensor, and a selector for selecting which light source to use depending on whether a one-dimensional or a two-dimensional symbol is being scanned.

Claims

1. An optical scanner for reading an optical code symbol having either a one-dimensional or a two-dimensional pattern of different light reflectivity, comprising:

a first and a second light source for respectively producing a first and a second laser light beam;

a scanning assembly for receiving one of the light beams and producing a respective outgoing light beam having either a one or a two-dimensional scanning pattern;

a collection mirror for receiving light reflected from the symbol and for directing the received reflected light along an optical path; and

a sensor lying in the optical path, for detecting the light directed by the collection mirror and for generating an electrical signal corresponding to the symbol.

2. The scanner as defined in claim 1, further comprising means for selecting either the first or the second light source for activation.

3. The scanner as defined in claim 1, wherein the first light source produces a beam spot with a generally elliptical cross-section in a working range of the scanner, and wherein the second light source produces a beam spot with a generally circular cross-section in the working range.

4. The scanner as defined in claim 1, wherein the scanning assembly includes

a) a first scan assembly including a first oscillatable mirror impinged by said one of the light beams;

b) a first drive for reciprocally oscillating the first mirror to sweep said one light beam along a y-direction;

c) a second scan assembly including a second, generally planar, oscillatable mirror impinged by said one light beam; and

d) a second drive for reciprocally oscillating the second mirror to sweep the light beam along an x-direction generally orthogonal to the y-direction to and across the symbol.

5. The scanner as defined in claim 4, wherein the first assembly includes a torsionally deformable element for supporting the first mirror.

6. The scanner as defined in claim 5, wherein the element has opposite, axial end regions, and wherein the first mirror is supported on the element at an intermediate region between the end regions of the element.

7. The scanner as defined in claim 5, wherein the element extends along an axis and has a cross-section, as considered in a plane perpendicular to the axis, having at least two portions forming an angle with respect to each other.

8. The scanner as defined in claim 5, wherein the first drive includes a permanent magnet mounted on the element, and an electromagnetic coil across which the element diametrically extends.

9. The scanner as defined in claim 4, wherein said second drive includes a flexible leaf spring on which the second scan mirror is mounted.

10. The scanner as defined in claim 9, wherein said second drive includes an energizable electromagnetic coil member and a permanent magnetic member in operational proximity thereto for imparting a force to the second mirror, thereby resulting in movement of the second mirror in an oscillating manner about a drive axis, and thereby causing the light beam reflected off the first mirror to sweep along a scanning path.

11. In an electro-optical reader for directing a light beam to, and for detecting light reflected from, bar code symbols to be read,

a retro-reflective scan module, comprising:

a) a generally planar, rectangular support;

b) a first and a second light source supported by the support, for generating and directing first and second light beams along first and second optical paths, respectively, to a symbol to be read;

c) a reciprocally oscillatable optical assembly mounted on the support, including first and second generally planar scan mirrors mounted in the first and second optical paths, respectively, for oscillating movement with respect to the support, and functioning to reflect one of the light beams from one of the light sources to the symbol, and a collection mirror for simultaneously receiving light reflected from the symbol and for directing the received reflected light along a third optical path;

d) a first drive supported by the support, for reciprocally oscillating the optical assembly to sweep said one light beam across the symbol; and

e) a sensor supported by the support and lying in the third optical path, for detecting the reflected light directed by the collection mirror and for generating an electrical signal corresponding to the symbol.

12. The module as defined in claim 11, wherein said support defines a reference plane, and wherein the first scan mirror is arranged such that said one light beam defines a scanning plane which is generally parallel to the support and sweeps bars and spaces of the symbol to read.

13. The module as defined in claim 11, wherein the optical assembly includes an aperture for receiving said one light beam from said one source and for permitting said one light beam to be transmitted.

14. The module as defined in claim 11, wherein the first drive reciprocally oscillates the first mirror to sweep said one light beam across the symbol at more than thirty times per second, said first drive including a flexible leaf spring on which the first mirror is mounted.

15. A hand-held portable computer unit, comprising:

a) data collection means for collecting and processing data; and

b) a plurality of accelerometers for determining a current position of the unit with respect to an initial position.

16. An arrangement for permanently visually indicating when an electronic device has been exposed to mechanical shock above a predetermined design limit, comprising:

a support mounted in the device; and

a movable mass coupled to the support by a breakable link that is designed to break due to movement of said mass caused by said shock.