Abstract:
An exemplary display device ( 200 ) includes a control circuit ( 22 ), a driving circuit ( 24 ), and a display module ( 25 ). The control circuit is configured to generate temperature compensation values according to ambient temperature signals inputted to the control circuit. The driving circuit is configured to generate compensated display signals according to the temperature compensation value generated by the control circuit. The display module is configured to receive the compensated display signals outputted by the driving circuit, and display images under the control of the compensated display signals. A method for driving the display device is also provided.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to display devices and, particularly, to a display device capable of automatically adjusting display signals according to ambient temperature. The present invention also relates to a method for driving such display device. 
       GENERAL BACKGROUND 
       [0002]    Display devices are widely used in various modern information products, such as notebooks, personal digital assistants (PDAs), video cameras, mobile phones and the like. Some display devices provide a function of temperature detection, in order that the user is made aware of the ambient temperature. 
         [0003]      FIG. 3  is an exploded diagram of a conventional display device with temperature detection function. The display device can be a mobile phone, for example. The display device  100  includes a shell  10 , a keyboard  11 , a control circuit  12 , a display module  13 , and a temperature sensor  14 . The shell  10  includes an outer surface (not labeled) and an inner accommodating space (not labeled). The keyboard  11  is installed at the outer surface of the shell  10 , and the display module  13  is installed in the inner accommodating space of the shell  10 . 
         [0004]    The display module  13  includes a main display area  15 , and a peripheral non-display area (not labeled) surrounding the display area  15 . The control circuit  12  and the temperature sensor  14  are both disposed on the non-display area  15  of the display module  13 . Moreover, the control circuit  12  is electrically coupled to the temperature sensor  14  and the display module  13 , respectively. The temperature sensor  14  is a thermal diode. 
         [0005]    In operation, the temperature sensor  14  detects the ambient temperature, converts a corresponding temperature signal to an analog electrical signal, and then outputs the analog electrical signal to the control circuit  12 . The control circuit  12  converts the analog electrical signal to a digital signal, and outputs the digital signal to the display module  13 . Finally, the display module  13  generates a display voltage according to the digital signal, and displays a corresponding numerical value in the display area  15  based on the display voltage. Thus, a numerical value representing the ambient temperature appears on the display device  100 , and can be conveniently read by a user. 
         [0006]    The ambient temperature is liable to influence electrical characteristics of inner elements in the display device  100 . That is, when the display device  100  is used in different environments, the electrical characteristics of the inner elements are apt to vary. For example, if the ambient temperature increases, the mobility of electrons in inner transistors of the display device  100  increases accordingly, so as to reduce the threshold voltages of the transistors. Therefore, output signals of the display device  100  are liable to drift. In the display device  100 , although alterations in the ambient temperature can be easily seen on the display module  13 , the problem of output signal drift caused by such alterations is not addressed. Ambient temperature changes can cause a variety of display defects on the display device  100 , such as unwanted increased response time, a decrease in the contrast ratio, flicker phenomenon, and the like. All these defects reduce the quality of the display. 
         [0007]    It is, therefore, desired to provide a display device which overcomes the above-described deficiencies. 
       SUMMARY 
       [0008]    In one aspect, a display device includes a control circuit, a driving circuit, and a display module. The control circuit is configured to generate temperature compensation values according to ambient temperature signals inputted to the control circuit. The driving circuit is configured to generate compensated display signals according to the temperature compensation value. The display module is configured to receive the compensated display signals, and display images under the control of the compensated display signals. 
         [0009]    In another aspect, a method for driving a liquid crystal display includes: detecting ambient temperature; generating temperature compensation values according to the ambient temperature; generating compensated display signals according to the temperature compensation values; and outputting the compensated display signals to a display module to drive the display module. 
         [0010]    Other novel features and advantages will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a block diagram of main components of a display device according to an exemplary embodiment of the present invention. 
           [0012]      FIG. 2  is a block diagram of a control circuit of the display device of  FIG. 1 . 
           [0013]      FIG. 3  is essentially an exploded, isometric view of a conventional display device with temperature detection function. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0014]    Reference will now be made to the drawings to describe preferred and exemplary embodiments of the present invention in detail. 
         [0015]      FIG. 1  is a block abbreviated diagram of a display device according to an exemplary embodiment of the present invention. The display device  200  is capable of automatically compensating display signals according to ambient temperature, and can for example be a mobile phone. The display device  200  includes a temperature sensor  21 , a control circuit  23 , a driving circuit  24 , a display module  25 , and a power circuit  27 . Typically, the temperature sensor  21 , the control circuit  23 , the display driving circuit  24 , and the power circuit  27  are all disposed in the display module  25 . 
         [0016]    The temperature sensor  21  is configured to convert an ambient temperature signal to an electrical signal, and is electrically coupled to the control circuit  23 . In the exemplary embodiment, the electrical signal is an analog voltage signal, which is outputted to the control circuit  23 . The temperature sensor  21  is typically a thermal diode. However, the temperature sensor  21  can instead be another kind of thermal sensing device, such as a thermal resistor, a thermal coupler, an infrared thermometer sensor, a microwave thermometer sensor, and the like. 
         [0017]      FIG. 2  is a block diagram of the control circuit  23 . The control circuit  23  is configured to provide a temperature compensation value according to the electrical signal generated by the temperature sensor  21 . The control circuit  23  includes an adjusting circuit  231 , an amplifier  232 , an analog to digital (A/D) converter  233 , a coder  235 , a micro control unit (MCU)  237 , and a storage unit  239 . The adjusting circuit  231 , the amplifier  232 , the A/D converter  233 , the coder  235 , and the MCU  237  are electrically coupled between the temperature sensor  21  and the driving circuit  24  in series. The storage unit  239  is electrically coupled to the MCU  237 . 
         [0018]    The adjusting circuit  231  is configured to adjust the analog voltage signal, so as to filter incidental interference signals simultaneously generated together with the analog voltage signal by the temperature sensor  21 . The amplifier  232  is configured to amplify the adjusted analog voltage signal. The A/D converter  233  is configured to convert the analog voltage signal outputted by the amplifier  232  to a digital signal. The coder  235  is configured to compress and code the digital signal to a binary code. Moreover, the storage unit  239  includes a plurality of temperature compensation values, each of which corresponds to a respective binary code. Once the MCU  239  receives a binary code from the coder  235 , it reads a corresponding temperature compensation value from the storage unit  239 , and outputs the temperature compensation value to the driving circuit  24 . 
         [0019]    Referring to  FIG. 1 , the driving circuit  24  is electrically coupled between the power circuit  27  and the display module  25 . The driving circuit  24  is configured to drive the display module  25  to display images according to the display signals and the temperature compensation value it receives. In addition, the power circuit  27  is configured to provide electrical power to the driving circuit  24 . The display module  25  can for example include a flat panel display (FPD), such as a liquid crystal display (LCD), a plasma display, an organic light emitting display (OLED), and the like. 
         [0020]    Operation of the display device  200  is typically as follows. When the ambient temperature of the display device  200  varies, a kinetic energy of inner conductive particles of the temperature sensor  21  increases or decreases accordingly. The inner conductive particles may for example be electrons and associated holes. The increase or decrease in kinetic energy causes the temperature sensor  21  to output an analog voltage signal to the control circuit  23 , the analog voltage signal corresponding to the ambient temperature. 
         [0021]    When the control circuit  23  receives the analog voltage signal, it filters the incidental interference signals from the analog voltage signal via the adjusting circuit  231 , and subsequently amplifies the adjusted analog voltage signal via the amplifier  232 . The analog voltage signal is then outputted to the A/D converter  233  by the amplifier  232 . In the A/D converter  233 , the analog voltage signal is sampled and quantized, so that it is converted to a digital signal. The digital signal is then outputted to the coder  235 . The coder  235  compresses and codes the digital signal, so that the digital signal is converted to a binary code. The binary code can be easily identified by the MCU  237 . The MCU  237  receives the binary code from the coder  235 , looks up a corresponding temperature compensation value from the storage unit  239 , and reads the corresponding temperature compensation value. In detail, when the binary code indicates that the ambient temperature has increased, the MCU  237  reads a temperature compensation value that corresponds to a negative compensation voltage. When the binary code indicates that the ambient temperature has decreased, the MCU  237  reads a temperature compensation value that corresponds to a positive compensation voltage. A value of each of the negative compensation voltage and the positive compensation voltage depends on the amount of alteration of the ambient temperature. Then the MCU  237  outputs the temperature compensation value to the driving circuit  24 . 
         [0022]    The driving circuit  24  receives a display signal from a peripheral circuit (not shown) such as a timing controller. The received display signal is independent of the temperature compensation value. The driving circuit  24  converts the display signal to a display voltage. The driving circuit  24  receives the temperature compensation value from the MCU  237  simultaneously with the display signal, and converts the temperature compensation value to the corresponding compensation voltage. Subsequently, the driving circuit  24  adds the compensation voltage to the display voltage, so as to regulate the display voltage output by the driving circuit  24 . Thus, when the ambient temperature has increased, the compensation voltage is negative, and the output display voltage is reduced. Conversely, when the ambient temperature has decreased, the compensation voltage is positive, and the output display voltage is increased. Thereby, display voltage drift that would otherwise occur due to the change in the ambient temperature is automatically compensated. 
         [0023]    Finally, the output display voltage is outputted to the display module  25 , and drives the display module  25  to display images. 
         [0024]    In summary, the display device  200  regulates the display signal according to the alteration in the ambient temperature as detected by the temperature sensor  21 . The temperature sensor  21  together with the control circuit  23  and the driving circuit  24  cooperate so as to compensate for any drift in the display signal that would otherwise occur due to the change in the ambient temperature. Thus, the display device  200  avoids being influenced by the ambient temperature. In particular, display defects otherwise caused by changes in the ambient temperature are reduced or even eliminated, and the quality of the display is improved. 
         [0025]    It is to be understood, however, that even though numerous characteristics and advantages of preferred and exemplary embodiments have been set out in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be made in detail within the principles of present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.