Method and apparatus for optically reading an information pattern

• US 5,949,056 A
• Filed: 11/22/1995
• Issued: 09/07/1999
• Est. Priority Date: 09/10/1986
• Status: Expired due to Fees

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Norand Corporation (Baker Hughes Company)
• Inventors: White, Jonathan R.
• Primary Examiner(s): Pitts, Harold I.
• Application Number:
  US08/561,991
• Time in Patent Office: 1,385 Days
• Field of Search: 235/472, 235/462.22, 235/472.01
• US Class Current: 235/472.01
• CPC Class Codes: B60R 16/0231 Circuits relating to the driving or the functioning of the vehicle monitoring tyres B60C23/00; indicating overspeed B60K31/00; for dash boards B60K37/00, B60Q3/10; for indicating emergencies B60Q1/52; brake control systems B60T; registering or indicating the working of vehicles G07C5/00; measuring distance G01C, e.g. combinations of speed and distance G01C23/00; engine indicators G01L; measuring speed or acceleration G01P
• CPC Class Codes: G06F 1/1626 with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06K 17/0022 arrangements or provisions for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 7/10574 Multiple sources
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10702 Particularities of propagating elements, e.g. lenses, mirrors G06K7/10831 takes precedence
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10811 Focalisation
• CPC Class Codes: G06K 7/10841 Particularities of the light-sensitive elements semiconductor devices H01L
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks
• CPC Class Codes: G07C 5/0808 Diagnosing performance data testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005
• CPC Class Codes: G07C 5/0858 wherein the data carrier is removable
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0032 Without explicit signalling
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 1/1685 : the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 69/18 : Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04M 7/006 : Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42
• CPC Class Codes: H04W 16/14 : Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 40/00 : Communication routing or communication path finding
• CPC Class Codes: H04W 52/0245 : according to signal strength
• CPC Class Codes: H04W 88/02 : Terminal devices
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

A portable, hand-held data terminal of modular structure includes a base module with a keyboard and a display screen. A data collection and communications module includes a stacked arrangement of a communications interface main circuit board, a radio and a laser scanner assembly which are housed in a housing shell which is attachable to the base module. The radio is mounted in spaced relationship to one side of the main circuit board, while the laser scanner assembly is mounted to the other side of the main circuit board. A support frame and a plurality of ground planes in the sandwiched main circuit board and a routing circuit board form an RF cage for shielding RF interference which may be generated by the radio. Also disclosed is a method for reducing the operational power consumption requirements of laser bar code scanners by analyzing reflected laser light in order to determine the presence of optically readable information sets. In a first embodiment, the reflected light intensity of a pulsed laser light beam is compared to the ambient light intensity to provide a control signal to actuate the scanning mode if a threshold differential is satisfied. In a second embodiment, a modulated laser light pulse is filtered to remove ambient light noise and then provides a control signal to actuate the scanning mode if a threshold value is reached.

Claims

1. A system for reading optically readable information sets, comprising:

(a) a scanner for generating a light beam directed toward an optically readable information set;

(b) a manually-operable actuator including a controller for operatively controlling the scanner such that said scanner may be selectively optimized to read optically readable information sets over a wide range of distances; and

(c) a detector for receiving reflected light from said optically readable information set to produce electrical means corresponding to data represented by such symbol.

2. The system according to claim 1, further comprising a housing having a handle for hand-held operation, and wherein the scanner and detector are disposed in the housing and the manually-operable actuator on the housing.

3. The system according to claim 2, herein the actuator includes a trigger operatively connected to the scanner to select between at least two distances within the operational range of said system.

4. The system according to claim 3, wherein the scanner includes a movable scan element operative for sweeping the light beam across the optically readable information set, and wherein the controller repetitively scans the scan element along arcs of limited angular distance, in a first operational state, and repetitively scans the scan element along arcs of predetermined angular distance greater than said limited angular distances in a second operational state, said states corresponding to said selectable positions of said control means.

5. The system according to claim 1, wherein said scanner comprises at least two distinct light sources for emitting at least two distinct light beams, each of said light beams being focussed such that each light source has a different working range at different distances from the light source.