Patent Publication Number: US-2007103473-A1

Title: Display apparatus and signal processing method thereof

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
      This application claims priority to Taiwan Patent Application No. 094139440 filed on Nov. 10, 2005.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a display apparatus; in particular, relates to a display apparatus and a signal processing method using a micro-controller and two buses for sharing workloads of an image processor.  
      2. Descriptions of the Related Art  
      Excluding the requirements for image display quality of display apparatuses on the market, system stability is also important. Consequently, the display apparatuses pay much attention to the information of system peripheral environment, such as detections of an internal temperature, a voltage status. Take conventional front projectors for example, in addition to the high-definition in projection, a long-term normal operation is also considered. In particular, bulbs with high radiant heat are chosen as a light source in the front projector. Therefore, cooling problems are extremely important that a disaster may be caused with improper handling.  
       FIG. 1  illustrates a basic structure of an internal control interface of a conventional front projector. The front projector comprises an image decoder  1 , a display module  2 , an image processor  3 , a bus  4  and an environmental monitoring module  5 . The image processor  3  processes digital image signals, output from the image decoder  1 , via the bus  4 , and then transmits it to the display module  2  for displaying an image via the bus  4 . The image processor  3  simultaneously communicates with the environmental monitoring module  5  via the bus  4  for monitoring the internal environment of the front projector. The environmental monitoring comprises temperature detection, fan rotation speed detection, voltage detection, and etc., to ensure that the front projector normally operates in a safe environment.  
      Generally, the image processor  3  sets up a plurality of independent procedures for executing the above-mentioned works synchronously. However, large amounts of data are required to be processed in the procedures and the same bus  4  is used to communicate with other devices. When a heavy workload occurs, the bus  4  could not transmit signals in real-time. Thus, the qualities of projection and environmental monitoring are affected. Furthermore, the bus  4  may turn paralyzed and have a direct effect upon the system stability.  
      According to the above descriptions, there exists a problem for current display apparatuses to be improved. In other words, it is an important topic that how to effectively share the workloads on the image processor and the transmitting interface thereof to ensure the operated system stable.  
     SUMMARY OF THE INVENTION  
      The primary objective of the present invention is to provide a display apparatus comprising a micro-controller, a detection module, an image processor, a first bus and a second bus, wherein the detection module is used for detecting a status of the display apparatus, the image processor is used for processing signals transmitted from the micro-controller, the first bus is used for electrically connecting with the image processor and the micro-controller, and the second bus is used for electrically connecting with the micro-controller and the detection module.  
      Another objective of the invention is to provide a signal processing method which is prosecuted by the above-mentioned display apparatus. The method comprises the steps as follows:  
      (a) detecting the status of the display apparatus by the detection module and transmitting a signal to the micro-controller via the second bus;  
      (b) transmitting the signal to the image processor by the micro-controller via the first bus; and  
      (c) processing the signal in the image processor which is transmitted from the micro-controller.  
      Consequently, information of a status detected by the detection module of the present invention is transmitted to the micro-controller via the second bus. The micro-controller reports the status information back to the image processor via the first bus when necessary in order to decrease the workloads on the image processor and the first bus. The purpose of enhancing system stability could be achieved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagram illustrating the front projector of the prior art; and  
       FIG. 2  is a diagram illustrating one embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      As show in  FIG. 2 , a preferred embodiment of a display apparatus of the present invention is a projector. The embodiment comprises a detection module  201 , an image processor  203 , a micro-controller  205 , a first bus  207 , a second bus  209 , an image decoder  211 , and a display module  213 . The detection module  201  is used for detecting a status of the projector. The image processor  203  is the DDP2000 chip manufactured by the Texas Instruments, wherein the image processor processes the digital image signals, output from the image decoder  211 , via the first bus  207 , transmits the digital image signals to the display module  213  via the first bus  207  for displaying an image, and processes signals transmitted from the micro-controller  205  simultaneously. The micro-controller  205  is connected with the detection module  201  via the second bus  209 . Consequently, information of a status detected by the detection module  201  is transmitted to the micro-controller  205  via the second bus  209 . The first bus  207  and the second bus  209  are Inter-Integrated Circuit (I 2 C) buses.  
      The micro-controller  205  may comprise a universal asynchronous receiver/transmitter interface (UART interface) or a general purpose input/output interface (GPIO interface). Both can be an interface connected to the second bus  209  individually.  
      The micro-controller  205  operates in response to a computer program. The computer program comprises a primary recursive code and an interrupt service code, wherein the primary recursive code is used for controlling the micro-controller  205  to process the signals transmitted via the second bus  209 , and the interrupt service code is used for requesting the micro-controller  205  to report the system status in response to the image processor  203  to control the micro-controller  205  interrupting the present executing tasks and to transmit report signals to the image processor  203  via the first bus  207 .  
      As shown in  FIG. 2 , the projector further comprises a light source  215 . The detection module  201  is used for detecting a temperature of the light source  215 . An overheat protection switch (not shown in the figure) is adjacently disposed to the light source  215 . When the detection module  201  detects that the light source  215  is overheated, the micro-controller  205  reports to the image processor  203  via the first bus  207 . Then, the image processor  203  cuts off the overheat protection switch to avoid the projector from overheating. The detection module  201  is also used for detecting the brightness of the light source  215  for properly adjusting a supply voltage for the light source  215  to maintain the brightness of the light source  215 .  
      As show in  FIG. 2 , the projector further comprises a fan  217 . The detection module  201  can detect a rotation speed of the fan  217  or a supply voltage for the fan  217  for adjusting the rotation speed of the fan  217  and then adjust an internal temperature of the projector.  
      The detection module  201  can further detect an environmental temperature, environmental brightness, or environmental atmospheric pressure for adjusting the light source  215  or the fan  217  at any time according to the environmental variations. For example, a faster rotation speed of the fan is needed when the atmospheric pressure is lower, to achieve same effects on cooling.  
      The detection module  201  further comprises a tilt sensor for detecting a tilt angle of the projector. The display module  213  can appropriately adjust an angle of the projected image according to the detected tilt angle for maintaining the projected image in horizontal. This function enables the projector to be disposed on any desk other than a horizontal tabletop.  
      Another embodiment of the present invention is a signal processing method prosecuted by the above-mentioned display apparatus. The method comprises the steps as follows. First, the detection module  201  detects the status of the display apparatus and transmits a signal corresponding to the status to the micro-controller  205  via the second bus  209 . Subsequently, the micro-controller  205  transmits the signal to the image processor  203  via the first bus  207 . Then, the image processor  203  processes the signal after the signal is received.  
      More specifically, according to the signal processing method disclosed in the present invention, the micro-controller  205  performs the primary recursive code to process the signal transmitted via the second bus  209 . When the image processor  203  requests the micro-controller reporting system statuses, the micro-controller  205  turns to perform the interrupt service code for interrupting the present executing tasks and processes the signal transmitted via the first bus  207 .  
      Depending on the aforesaid method, the status could be corresponding to the temperature or brightness of the light source  205 , the rotation speed or the supply voltage of the fan  205 , the environmental temperature, the environmental brightness, the environmental atmospheric pressure, or the tilt angle of the display apparatus.  
      According to the above descriptions, the information of the status detected by the detection module  201  of the present invention is transmitted to the micro-controller  205  via the second bus  209 . The image processor  203  processes the display of images via the first bus  207 . The micro-controller  205  only reports the status information to the image processor  203  via the first bus  207  when necessary. Consequently, the present invention greatly decreases the workloads of the image processor  203  and the first bus  207  and achieves the purpose of enhancing the system stability.  
      The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.