Patent Publication Number: US-2005128365-A1

Title: Vehicle display device with infrared transmission

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a vehicle display device, and more particularly to a vehicle device capable of wirelessly transmitting audio signals via infrared transmission technique to an earphone.  
      2. Description of Related Art  
      Vehicle display devices (monitor) have become popular accessories for vehicles, and may be used in a wide variety of applications. For example, the display device may be used in a vehicle as a computer monitor, a navigating system display, a television, etc. The vehicle display devices may be mounted at any of various locations within the vehicle, depending on the vehicle configuration and the intended use of the monitor. The most desired location where display devices may be mounted is on the ceiling of the vehicle.  
      In some situations, the vehicle display device is used for other passengers not the driver. However, the sound broadcast from the display device may still distract the vehicle driver and affect the safety of the vehicle. Therefore, it is desired to provide a way to obviate the aforementioned drawback.  
     SUMMARY OF THE INVENTION  
      The main objective of the present invention is to provide a vehicle display device that is able to transmit audio signals via the infrared technique to prevent possible distraction of the driver, meanwhile other passengers still can listen to the display device by use of proper earphones.  
      Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a plan view of a vehicle display device in accordance with the present invention;  
       FIG. 2  is a circuit block diagram of the vehicle display device in accordance with the present invention;  
       FIGS. 3A-3G  show a detailed circuit diagram of an input interface shown in  FIG. 1 ;  
       FIGS. 4A-4C  show a detailed circuit diagram of an MCU shown in  FIG. 1 ;  
       FIGS. 5A-5D  show a detailed circuit diagram of a video decoder in  FIG. 1 ;  
       FIGS. 6A-6B  show a detailed circuit diagram of a panel interface of  FIG. 1 ;  
       FIG. 7  is a circuit diagram of an on-screen display (OSD) circuit in accordance with the present invention;  
       FIGS. 8A-8B  show a circuit diagram of an audio amplifier of  FIG. 1 ;  
       FIGS. 9A-9E  show a circuit diagram of an infrared earphone transmitter of  FIG. 1 ; and  
       FIGS. 10A-10D  is a circuit diagram of an inverter and power circuit of  FIG. 1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      With reference to  FIGS. 1 and 2 , a vehicle display device in accordance with the present invention mainly comprises an input interface ( 10 ), a micro-control unit ( 20 ), a video decoder ( 30 ), a panel interface ( 40 ), an audio amplifier ( 50 ) and an infrared earphone transmitter ( 60 ). An inverter and power unit ( 70 ) provides operating voltages to the foregoing elements, where the detailed circuit diagram of the inverter and power unit ( 70 ) is illustrated in  FIGS. 10A-10D .  
      With reference to  FIGS. 1 and 3 A- 3 G, audio video (AV) signals can be input to the vehicle display device through either a first connector ( 11 ) or a second connector ( 12 ) of the input interface ( 10 ). Based on the control commands of the micro-control unit ( 20 ), the desired AV signal is selected from one of the two connectors ( 11 ,  12 ). The detailed circuits of the micro-control unit ( 20 ) are depicted in  FIGS. 4A-4C , wherein the operations status table of the micro-control unit ( 20 ) is shown as follows:  
                                           PORT   I/O   initial value                      VOLUME-PWM       PWM = 0           PWR-LAMP   O   HIGH   LO: POWER ON       PWR-SYS       HIGH   LO: POWER ON       +12 V = DET   I   A/D       KEY-DET   I   A/D       LED-RED   O   HIGH       LED-GREEN   O   HIGH       IR-DATA   I   INT0       DOOR-CLOSE-DET   I       AUX-IN   I       VIDEO-IN-DET   I       RB5P-DATA   O   HIGH       RB5P-CLK   O   HIGH       RB5P-CS   O   HIGH       UP/DOWN   O   HIGH   LO: UP-&gt;DOWN       LEFT/RIGHT   O   HIGH   LO: LEFT-&gt;RIGHT       NTSC/PAL   O   HIGH   HIGH: NISC/LO: PAL       ZOOM1   O   HIGH       ZOOM2   O   HIGH       ZOOM3   O   HIGH                  
 
      The video component of the AV signals is sent to the video decoder ( 30 ), and the audio component is transmitted to the audio amplifier ( 50 ) and the IR earphone transmitter ( 60 ).  
      With reference to  FIGS. 5A  to  6 B, after the video decoder ( 30 ) decodes the received video signals, the decoded video data are then transmitted to the panel interface ( 40 ) through which an LCD display panel (not shown) is allowing to show the video images. As shown in  FIGS. 1 and 7 , an on-screen display (OSD) circuit ( 80 ) is further connected to the video decoder ( 30 ) and controlled by the micro-control unit ( 20 ). The OSD circuit ( 80 ) provides a function that the setting parameters relevant to the LCD display panel is directly shown on the panel with which a user is able to adjust the setting such as the vertical size or horizontal size of displayed images.  
      With reference to  FIGS. 8A  to  9 E, the audio signals from the input interface ( 10 ) are input to the audio amplifier ( 50 ) and the IR earphone transmitter ( 60 ). The amplified audio signals from the amplifier ( 50 ) can be broadcast via a speaker (not shown). In another aspect, the audio signals are converted to infrared signals by the IR earphone transmitter ( 60 ) and then emitted wirelessly to an IR earphone. Through the use of the IR earphone, vehicle passengers still can listen to sounds while they are watching the videos on the display device, yet the driver not wearing such an earphone is not distracted by the sounds enjoyed by the passengers. It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the 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 invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.