Patent Publication Number: US-11393412-B2

Title: Electronic device and temperature adjustment method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China Application Serial No. 202110330511.X, filed on Mar. 25, 2021, and U.S. provisional application Ser. No. 63/017,038, filed on Apr. 29, 2020. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The disclosure relates to an electronic device and a temperature adjustment method thereof. 
     Description of the Related Art 
     Heat generated in a display device is dissipated by using a fan and related dissipation mechanism. The temperature of the display device is detected by a sensor. If the temperature of the display device increases, the rotation speed of the fan is increased to dissipate heat. However, noise occurs when the rotation speed increases, and the heat dissipation efficiency is restricted by the upper limit of the rotation speed of the fan. Therefore, it is difficult to maintain the temperature of the display device below an upper limit temperature. As a result, the display device cannot maintain in an optimal operation temperature range with high brightness for a long time. If the temperature continues to increase and exceeds the upper limit of the operation temperature of the display device for a long time, the display device is damaged, and fails to maintain at a stable quality. 
     BRIEF SUMMARY OF THE INVENTION 
     According to the first aspect of the disclosure, an electronic device is provided. The electronic device includes a display panel and a processor. The display panel is configured to display image data and includes a backlight module, and the processor is electrically connected to the display panel. The processor averages current values of the backlight module corresponding to the image data in a first time period, to generate an average current value, and compares the average current value with a current threshold. When the average current value is greater than the current threshold, the processor generates an adjusted maximum current value, and correspondingly reduces current values of the backlight module in a second time period according to the adjusted maximum current value, to reduce a temperature of the electronic device. 
     According to the second aspect of the disclosure, T a temperature adjustment method of an electronic device is provided. The electronic device includes a display panel. The temperature adjustment method includes: averaging current values of a backlight module of the display panel corresponding to image data in a first time period to generate an average current value; comparing the average current value with a current threshold; generating an adjusted maximum current value when the average current value is greater than the current threshold; and reducing current values of the backlight module in a second time period according to the adjusted maximum current value, to reduce a temperature of the electronic device. 
     In conclusion, in the disclosure, it is determined that whether the temperature of an electronic device is excessively high according to current values of a backlight module corresponding to displayed data in a time period, and there is no need to provide an additional temperature sensor. Therefore, the temperature of the electronic device is dynamically reducing by reducing the current values of the backlight module without increasing costs, allowing the operation temperature of the display device to be maintained in a preset operation temperature range. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of an electronic device according to an embodiment of the disclosure. 
         FIG. 2  is a schematic flowchart of a temperature adjustment method according to an embodiment of the disclosure. 
         FIG. 3  is a schematic diagram showing a current change of a backlight module according to an embodiment of the disclosure. 
         FIG. 4  is a schematic diagram showing a current change of a backlight module according to another embodiment of the disclosure. 
         FIG. 5  is a schematic diagram of adjusting a current value of a backlight module according to an embodiment of the disclosure. 
         FIG. 6  is a schematic diagram of adjusting a current value of a backlight module according to another embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring to  FIG. 1 , an electronic device  10  includes at least a display panel  12  and a processor  14 . The processor  14  is electrically connected to the display panel  12 . The display panel  12  further includes a backlight module  121 . The processor  14  transmits image data to the display panel, so that the display panel  12  displays the image data. An upper limit current value of the backlight module  121  is a maximum current value. The processor  14  calculates a current value of the backlight module  121  corresponding to the image data according to the image data and the maximum current value. In an embodiment, the processor  14  is an image processor. 
     In an embodiment, the electronic device  10  is a light-emitting diode (LED) display, a notebook computer, a tablet computer, or a mobile phone. 
     Referring to  FIG. 1  and  FIG. 2 , in the electronic device  10 , the processor  14  executes a temperature adjustment method, to enable the display panel  12  to maintain at a stable temperature when displaying the image data. The temperature adjustment method includes the steps described hereinafter. In step S 10 , the processor  14  averages current values of the backlight module  121  corresponding to the image data in a first time period T 1 , to generate an average current value I avg . In an embodiment, the first time period T 1  is less than or equal to a time period that required for the electronic device  10  to operate at a maximum current value I max  to reach an equilibrium temperature. In an embodiment, the processor  14  calculates a current value of the backlight module  121  according to displayed image content of the image data, and acquires all the current values in the first time period T 1  to calculate the average current value I avg . 
     Next, in step S 12 , the processor  14  compares the average current value I avg  with a current threshold I c  to determine whether the average current value I avg  is greater than the current threshold I c . When the processor  14  determines that the average current value I avg  is less than or equal to the current threshold I c  (I avg ≤I c ), step S 10  is performed again to calculate an average current value I avg  in a next first time period T 1 . When the processor  14  determines that the average current value I avg  is greater than the current threshold I c  (I avg &gt;I c ), step S 14  is performed. 
     In step S 14 , the processor  14  generates an adjusted maximum current value I a  when the average current value I avg  is greater than the current threshold I c . Specifically, the processor  14  multiplies the maximum current value I max  of the backlight module  121  by an adjustment parameter r, which is expressed as I max *r, to generate the adjusted maximum current value I a  (I a =I max *r), where the adjustment parameter r is less than 1. In an embodiment, the processor  14  further selects different adjustment parameters r according to different average current values I avg . The larger the average current value I avg  is, the smaller the adjustment parameter r is; the smaller the average current value I avg  is, the larger the adjustment parameter r is. 
     As shown in step S 16 , the processor  14  reduces current values of the backlight module  121  in a second time period T 2  according to the adjusted maximum current value I a  (in an embodiment, the processor reduces current values that exceeding the adjusted maximum current value I a  in the current values of the backlight module  121  in the second time period T 2  to the adjusted maximum current value I a ; or multiplies all the current values of the backlight module  121  in the second time period T 2  by the adjustment parameter r, to reduce all the current values), to reduce a temperature of the electronic device  10 . In an embodiment, the second time period T 2  is less than or equal to a heat dissipation time. The heat dissipation time is a time period required for the electronic device  10  to operate at the current threshold I c  and drop to an equilibrium temperature after reaching an upper limit temperature. 
     As shown in step S 18 , the processor  14  adjusts an upper limit current value of the backlight module  121  from the adjusted maximum current value I a  to the maximum current value I max  after the second time period T 2 . Then, the process goes back to step S 10  to start a new calculation cycle and repeat the foregoing steps, thus to dynamically adjust the temperature of the electronic device  10  by dynamically adjusting the current value of the backlight module  121 . 
     Referring to  FIG. 1 ,  FIG. 2 , and  FIG. 3 , in the first time period T 1  in step S 10 , when the backlight module  121  operates at the maximum current value I max  for a long time, the temperature of the electronic device  10  continues to increase. In step S 16 , after the processor  14  reduces the upper limit current value of the backlight module  121  to the adjusted maximum current value I a , none of the current values of the backlight module  121  in the second time period T 2  is greater than the adjusted maximum current value I a , so the temperature of the electronic device  10  gradually decreases. Therefore, heat is dissipated from the electronic device  10 , and the temperature of the electronic device  10  (the display panel  12 ) is maintained within a stable range. The upper limit current value of the backlight module  121  is adjusted to the original maximum current value I max  after the second time period T 2 . 
     In an embodiment, the processor  14  further sets different second time periods T 2  according to the average current value I avg . 
     Referring to  FIG. 1  and  FIG. 2 , in step S 12  of comparing the average current value I avg  with the current threshold I c , in an embodiment, there are a plurality of current thresholds I c . Each current threshold I c  corresponds to one adjustment parameter r, and the current threshold I c  is selected according to the average current value I avg . In an embodiment, the processor  14  selects a current threshold I c  that is the most closest to the average current value I avg  from the current thresholds I c  that are less than the average current value I avg , and accordingly performs the next step S 14 , to differently generate the adjusted maximum current values I a . Referring to  FIG. 4 , in an N th  time period T N , an upper limit current value of the backlight module  121  is a maximum current value I max . In an (N+1) th  time period T N+1 , since the processor  14  reduces the upper limit current value of the backlight module  121  from the maximum current value I max  to an adjusted maximum current value I a , none of the current values of the backlight module  121  in the (N+2) th  time period T N+1  is greater than the adjusted maximum current value I a . In an (N+2) th  time period T N+2 , the processor  14  sets the upper limit current value of the backlight module  121  back to the maximum current value I max . In an (N+3) th  time period T N+3 , the processor  14  reduces the upper limit current value of the backlight module  121  to an adjusted maximum current value I a . In an (N+4) th  time period T N+4 , the processor  14  sets the upper limit current value of the backlight module  121  back to the maximum current value I max  again. In an (N+5) th  time period T N+5 , the processor  14  reduces the upper limit current value of the backlight module  121  to an adjusted maximum current value I a . The rest is deduced by analogy. In this embodiment, in the (N+1) th  time period T N+1 , the (N+3) th  time period T N+3 , and the (N+5) th  time period T N+5 , the adjusted maximum current values I a  are exactly the same, which indicates that average current values I avg  previously calculated in the first time period T 1  are the same. In some other embodiments, if the calculated average current values I avg  are different, the adjusted maximum current values I a  in the (N+1) th  time period T N+1 , the (N+3) th  time period T N+3 , and the (N+5) th  time period T N+5  correspond to different values. 
     In an embodiment, referring to  FIG. 1  and  FIG. 2 , in step S 16  of reducing the current values of the backlight module  121  in the second time period T 2  according to the adjusted maximum current value I a , there are three manners for reducing the current values of the backlight module  121 . The first adjustment manner is that the processor  14  reduces the current values of the backlight module  121  by adjusting an upper limit current value of the backlight module  121 . In an embodiment, the maximum current value I max  is 300 A, the upper limit current value of the backlight module  121  in the second time period T 2  is directly adjusted to half the maximum current value I max  (150 A). The second adjustment manner is that the processors  14  gradually changes the current values. In an embodiment, the upper limit current value of the backlight module  121  is gradually adjusted to half the maximum current value I max  (150 A) in an adjustment time interval. 
     The third adjustment manner is that the processor  14  adjusts the current values of the backlight module  121  by changing a pulse width modulation (PWM) setting. In an embodiment, an original setting that a current value of 300 A is outputted at a specific quantity of time points in the second time period T 2  is adjusted to a setting that a current value of 300 A is outputted only at half the specific quantity of time points in the second time period T 2 . 
     Based on the above, whatever the adjustment is implemented by directly changing the upper limit current value or by setting the PWM, the current value of the backlight module  121  is allowed to be adjusted either instantaneously or gradually. Referring to  FIG. 1  and  FIG. 5 , the processor  14  instantaneously reduces the upper limit current value of the backlight module  121  from the maximum current value I max  to the adjusted maximum current value I a  or instantaneously increases the upper limit current value from the adjusted maximum current value I a  to the maximum current value I max . Referring to  FIG. 1  and  FIG. 6 , the processor  14  gradually reduces the upper limit current value of the backlight module  121  from a maximum current value I max  to the adjusted maximum current value lain a time interval, or gradually increases the upper limit current value from the adjusted maximum current value I a  to the maximum current value I max  in a time interval. The gradual adjustment mode decreases the discomfort feelings that caused by an abrupt change of picture brightness. 
     In an embodiment, a rising trend of the temperature of the electronic device is observed for different current settings, so as to learn temperature changes corresponding to the current settings, and a current operation temperature is measured or calculated, to figure out a current-time-temperature correlation, so that subsequently the temperature controlling is achieved by changing the current at intervals of a period of time. Such a current change behavior is periodic, and therefore, the temperature is controlled by periodically adjusting the current value of the backlight module. The rising trends of the temperature of the electronic device and equilibrium temperatures corresponding to different current values of the backlight module are recorded, and a time period required for the electronic device to reach an equilibrium temperature ranges from 0.5 hour to 2 hours. Therefore, the following information is learned in advance: the time period that required for the electronic device operating at the maximum current value to reach an equilibrium temperature; the equilibrium temperatures reached at different currents, where it is learned that an equilibrium temperature reached at the current threshold is less than an upper limit temperature of the electronic device (display panel) by a predetermined temperature difference (which is 5° C. in an embodiment), and the current threshold is regarded as the most stable current value; and a time period required for the electronic device operating at the current threshold that drops to the equilibrium temperature after reaching the upper limit temperature (heat dissipation time period). Therefore, in the disclosure, two or more time periods, such as the first time period and the second time period, are set according to the foregoing information. 
     In conclusion, in the disclosure, it is determined that whether the temperature of an electronic device is excessively high according to current values of a backlight module corresponding to the displayed data in a time period, and there is no need to provide an additional temperature sensor. Therefore, the temperature of the electronic device is dynamically reducing by reducing the current values of the backlight module without increasing costs, allowing the operation temperature of the display device to be maintained in a set operation temperature range. 
     In addition, the brightness of the display panel is brighter or darker as the current value of the backlight module is adjusted higher or lower, therefore, users are able to determine whether the electronic device is in a cooling mode by observing a change in the brightness of the display panel. 
     The embodiments described above are only used for explaining the technical ideas and characteristics of the disclosure to enable a person skilled in the art to understand and implement the content of the disclosure, and are not intended to limit the patent scope of the disclosure. That is, any equivalent change or modification made according to the spirit disclosed in the disclosure shall still fall within the patent scope of the disclosure.