Patent Publication Number: US-8525930-B2

Title: Electronic billboard

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to electronic billboards and, particularly, to a electronic billboard with touch panel. 
     2. Description of Related Art 
     One of the best ways to win customers is through advertising. Electronic billboards are a popular venue for showing advertising. However, the electronic billboards generally show contents on a full screen, no matter how far away viewers are, after a while this becomes boring for the viewers. Furthermore, the electronic billboards also cannot interact with viewers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components of the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of an electronic billboard. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views. 
         FIG. 1  is a block diagram of the electronic billboard in accordance with an exemplary embodiment. 
         FIG. 2  is an exemplary relationship table employed in the electronic billboard of  FIG. 1 . 
         FIG. 3  is a schematic diagram showing content changes on the electronic billboard of  FIG. 1  relating to distances of viewers 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of an electronic billboard  100 , in accordance with an embodiment. The electronic billboard  100  includes a display unit  10 , a distance detection unit  20 , a storage unit  30 , a processing unit  40 , and an operable unit  50 . 
     The distance detection unit  20  is used to detect distances between viewers and the electronic billboard  100  (hereinafter “the viewer distances”) within the detectable range of the distance detection unit  20 . In this embodiment, the distance detection unit  20  is an ultrasonic ranging sensor. The ultrasonic ranging sensor includes an ultrasonic transmitter  21 , an echo receiver  22 , a time control  23 , and an arithmetic unit  24 . The ultrasonic transmitter transmits  21  ultrasonic waves for every time period T. The time period T is preset to be longer than the time needed by the ultrasonic waves traveling from the ultrasonic transmitter  21  to a viewer, and back to the echo receiver  22  when the viewer distance of the viewer is the longest in the detectable range. The time control  23  records a time point for the ultrasonic waves that are being transmitted and a time point for the ultrasonic waves that are being received to obtain a time duration of the ultrasonic waves travelling from the ultrasonic transmitter to the echo receiver. The arithmetic unit  24  based on the time duration can calculate the measured distance. 
     The storage unit  30  stores content for the electronic billboard  100  to display and a relationship table. The relationship table records a relation between viewer distances and zoom in or zoom out proportions of displayed content (hereinafter “the zoom proportions”). Referring to  FIG. 2 , each of the zoom proportions corresponds to a viewer distance range. In other embodiments, the storage unit  30  stores a formula defining the relation between zoom proportion and viewer distance. For example, the formula defines a linearly direct ratio relation between zoom proportion and viewer distance. 
     The processing unit  40  includes a mode selection module  41  and a zoom proportion control module  42 . The mode selection module is used to select a display mode according to a comparison result of a viewer distance with a predetermined distance. The zoom proportion control module  42  is used to control the display unit  10  to display contents with a zoom in or zoom out proportion corresponding to the viewer distance according to the relationship table. In this embodiment, the modes include a zoom mode and an interactive mode. The mode selection module  41  chooses the interactive mode when at least one of the detected viewer distances is less than the predetermined distance, and chooses the zoom mode when the detected viewer distances is greater than or equal to the predetermined distance. 
       FIG. 3  is a schematic diagram showing content changes in three different viewer distances. First, the viewer stops relatively far from the electronic billboard  100  and the viewer distance L 1  of this viewer is farther than the predetermined distance L A , the mode selection module  41  sends a zoom mode displaying instructions to the zoom proportion control module  42 . The zoom proportion control module  42  drives the display unit  10  to display the content with a zoom proportion corresponding to the viewer distance L 1  according to the relationship table. 
     When the viewer moves towards the electronic billboard  100 , and the viewer distance changes to L 2 , the zoom proportion control module  42  drives the display unit  10  to display content with another zoom proportion corresponding to the viewer distance L 2  according to the relationship table. The zoom proportion decreases when the viewer moves towards the electronic billboard  100 . 
     When the viewer moves to a viewer distance L 3  less than the predetermined distance L A , the processing unit  40  sends an interactive mode displaying instructions to the zoom proportion control module  42 , the zoom proportion control module  42  drives the display unit  10  to display an interactive interface, and activates the operable unit  50  for viewers to operate. The operable unit  50  can be a touch panel, a mouse, five keys control, a keyboard, or a gesture control. In this embodiment, the display unit  10  is divided into two areas. The first area  141  displays content with zoom mode and the second area  142  displays an operable interface with interactive mode. The viewer can operate the operable unit  50  to get useful information, such as discounts or new arrivals from the operable interface. 
     In other embodiments, when there are more than one detected viewer distances longer than the predetermined distance L A , the zoom proportion control module  42  computes the average of the viewer distances, and drives the display unit to display content with a zoom proportion corresponding to the average according to the relationship table. 
     The zoom proportion control module  42  drives the display unit  10  to display the largest zoom proportion when there is no viewer in the detectable range. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the present disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.