Laser diode scanner with improved shock mounting

• US 4,896,026 A
• Filed: 10/31/1988
• Issued: 01/23/1990
• Est. Priority Date: 10/31/1988
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Krichever, Mark, Gofman, Yuri, Shepard, Howard M.
• Primary Examiner(s): Pitts, Harold I.
• Application Number:
  US07/265,548
• Time in Patent Office: 449 Days
• Field of Search: 235/472, 235/455, 235/462, 235/454
• US Class Current: 235/472.01
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners

Abstract

Optical alignment between components in a head of a laser scanner is maintained in the event of external shock. Optical and scanning component assemblies are shock-mounted near their respective centers of mass. A flexible, printed circuit board on which the assemblies are mounted serves as an alignment fixture.

Claims

1. In a laser scanning system for reading indicia having portions of different light reflectivity, said system being of the type including

(A) a hand-held head normally supportable by a user in an intended position of use;

(B) an optical assembly located in the head, having a center of mass, and including

(i) laser diode for emitting a laser beam with concomitant generation of heat,

(ii) a heat sink for conducting the heat away from the diode,

(iii) optic means for optically forming and modifying the laser beam to have a predetermined beam cross-section at a reference plane in the vicinity of which indicia to be read are located and impinged by the laser beam, thereby reflecting off the indicia reflected laser light, at least a returning portion of which travels away from the indicia back toward the head, and

(iv) sensor means for detecting the returning portion of the reflected laser light, and for generating an electrical signal indicative of the indicia being read; and

(C) a scanning assembly located in the head, having a center of mass, and including

(i) a reciprocally oscillatable scanning motor having a drive shaft on which a mirror is mounted for joint repetitive and cyclical oscillating movement a plurality of times per second, said mirror directing the laser beam toward the reference plane and to and across the indicia to be read for scanning the same, said mirror also collecting the returning portion of the reflected laser light and directing the same to the sensor means,

the improvement which comprises;

(a) means for shock mounting the assemblies relative to the head, including

(i) a first pair of shock mounts within the head and aligned along a first axis which extends generally through the center of the mass of the scaning assembly, and

(ii) a second pair of shock mounts within the head and aligned along a second axis which extends generally through the center of mass of the optical assembly; and

(b) a printed circuit board supported by, and extending between, the assemblies for maintaining the assemblies in optical alignment.

2. The improved system as recited in claim 1, wherein the scanning motor is the heaviest component in the scanning assembly and is located in the vicinity of the first axis, and wherein the heat sink is the heaviest component in the optical assembly and is located in the vicinity of the second axis.

3. The improved system as recited in claim 2, wherein the head has an elongated barrel having front and rear interior regions at opposite ends of the barrel, and wherein the scanning and optical assemblies are located at respective interior regions for better balance of the head.

4. The improved system as recited in claim 1, wherein the printed circuit board is a relatively thin and flexible sheet.

5. The improved system as recited in claim 4, wherein the printed circuit board has opposite end regions, and wherein the scanning and optical assemblies are located at respective end regions of the board.

6. A laser scanning module, comprising:

(A) an optical assembly having a center of mass, and including

(i) a laser diode for emitting a laser beam with concomitant generation of heat,

(ii) a heat sink for conducting the heat away from the diode,

(iii) optic means for optically forming and modifying the laser beam to have a predetermined beam crosssection at a reference plane in the vicinity of which indicia to be read are located and impinged by the laser beam, thereby reflecting off the indicia reflected light, at least a returning portion of which travels away from the indicia back toward the module, and

(iv) sensor means for detecting the returning portion of the reflected laser light, and for generating an electrical signal indicative of the indicia being read;

(B) a scanning assembly having a center of mass, and including

(i) a reciprocally oscillatable scanning motor having a drive shaft on which a mirror is mounted for joint repetitive and cyclical oscillating movement a plurality of times per second, said mirror directing the laser beam toward the reference plane and to and across the indicia to be read for scanning the same, said mirror also collecting the returning portion of the reflected laser light and directing the same to the sensor means;

(C) a printed circuit board supported by, and extending between, the assemblies for maintaining the assemblies in optical alignment; and

(D) means for shock mounting the assemblies, including

(i) a first pair of shock mounts on the board and aligned along a first axis which extends generally through the center of the mass of the scanning assembly, and

(ii) a second pair of shock mounts on the board and aligned along a second axis which extends generally through the center of mass of the optical assembly.

7. The improved system as recited in claim 6, wherein the scanning motor is the heaviest component in the scanning assembly and is located in the vicinity of the first axis, and wherein the heat sink is the heaviest component in the optical assembly and is located in the vicinity of the second axis.

8. The improved system as recited in claim 6, wherein the printed circuit board is a relatively thin and flexible sheet.

9. The improved system as recited in claim 6, wherein the printed circuit board has opposite end regions, and wherein the scanning and optical assemblies are located at respective end regions of the board.