Pricing display system

• US 5,504,475 A
• Filed: 01/19/1994
• Issued: 04/02/1996
• Est. Priority Date: 02/16/1990
• Status: Expired due to Term

• Current Assignee: Sitour Electronic Systems
• Original Assignee: Sitour Electronic Systems
• Inventors: Houdou, Michel, Morineau, Jacques
• Primary Examiner(s): ZIMMERMAN, BRIAN A
• Application Number:
  US08/185,306
• Time in Patent Office: 804 Days
• Field of Search: 340/825.35, 340/825.36, 340/825.44, 340/825.47, 340/825.73, 340/756, 455/343, 455/38.3
• US Class Current: 340/5.91
• CPC Class Codes: G06F 3/147 using display panels
• 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: G06Q 30/02 Marketing; Price estimation or determination; Fundraising
• CPC Class Codes: G09F 2027/001 Comprising a presence or proximity detector
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2380/04 Electronic labels
• CPC Class Codes: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A system comprises a central unit and a plurality of display modules each adapted to show on a display information received from the central unit, for example for displaying prices in a store. The central unit comprises a transmitter including a current loop fed with a low-frequency signal modulated according to the information to be transmitted and the system comprises, associated with each display module or group of display modules, a receive circuit, a receive antenna coupled electromagnetically to said current loop and a device for activating the receive circuit at predetermined periods for a limited duration. Each transmission of information by the central unit is preceded by the transmission of a reactivation signal which, when detected by the receive circuit during a phase in which the latter is active, causes it to be held in the active state for at least part of the duration for which said information is transmitted.

Claims

1. A system comprising a central unit and a plurality of display modules each adapted to show on a display device information received from said central unit, for displaying prices in a store, wherein said central unit comprises transmission means including a current loop fed with a low-frequency signal modulated according to display and control information to be transmitted, said transmission means for transmitting the modulated low-frequency signal to the display modules, and further comprising, in each display module, a battery, a reception circuit, a reception antenna electromagnetically coupled to said current loop and means for activating the reception circuit at predetermined periods and for a limited duration, wherein each transmission of information by said central unit is preceded by the transmission of a reactivation signal which, when detected by said reception circuit during a period of time in which said reception circuit is active, causes it to be held in the active state for at least part of the duration for which said information is transmitted, said system further comprising at least one portable terminal comprising means for generating initialization information to be transmitted to display modules and means for transmitting said initialization information by means of a second current loop fed with a low-frequency signal modulated according to said initialization information, said initialization information being transmitted to a display module by close electromagnetic coupling between said second current loop and said antenna of the display module, wherein the magnitude of the electromagnetic field received by a display module from said first loop is substantially lower than the magnitude of the electromagnetic field received from said second loop when said portable terminal is brought close to said display module, and each display module comprises field amplitude detection means for differentiating between remote transmission of display or control information from the central unit and proximity transmission of initialization information from said portable terminal;

wherein said field amplitude detection means are activated at a second period shorter than said first activation period.

2. The system according to claim 1, wherein the information to be transmitted by the central unit comprises an instruction for remotely disabling the periodic activation of the field amplitude detection means of a selected group of display modules for a duration as determined by said instruction and corresponding to a period during which no information is intended to be received by said selected display modules from said portable terminal, whereby the life of the batteries of said selected display modules is extended.