Abstract:
A portable device and associated computer-implemented method are provided. The method includes the steps of: utilizing an ambient light sensor of the portable device to detect ambient light around the portable device to generate a first sensing signal; determining whether the first sensing signal is smaller than a first threshold; when it is determined that the first sensing signal is smaller than the first threshold, controlling a display panel of the portable device to enter a low-power mode; determining whether the first sensing signal is larger than a second threshold when the display panel has entered the low-power mode; and when it is determined that the first sensing signal is larger than the second threshold and the display panel has entered the low-power mode, controlling the display panel to enter a normal display mode from the low-power mode.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    Field of the Invention 
         [0002]    The invention relates to a portable device, and, in particular, to a portable device equipped with a transflective or reflective display and associated control method capable of utilizing ambient light sensors and/or motion sensors to reduce power consumption of the display of the portable device. 
         [0003]    Description of the Related Art 
         [0004]    With advances in technology, a transflective display or a reflective display has been used in a portable device for saving power. These kinds of displays can reflect environment light, such as daylight, as its backlight. When the environment light is sufficient, it does not cost any power for the backlight. 
         [0005]    Generally, the transflective display or the reflective display is usually implemented by a liquid-crystal display (LCD), or an organic light-emitting diode (OLED) display due to their superior display performance. However, an LCD or OLED display needs power to refresh the display content, and it may cost much power and reduce the battery life. Accordingly, there is demand for a portable device to solve the aforementioned issue. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
         [0007]    A portable device is provided. The portable device includes an ambient light sensor; and a control module. The ambient light sensor is configured to detect ambient light around the portable device to generate first sensing signal. The control module is configured to generate display content to be displayed on the display panel, and gather the first sensing signal from the ambient light sensor. When the control module determines the first sensing signal is smaller than the first threshold, the control module controls the display panel to enter a sleep mode. When the control module determines the first sensing signal is larger than a second threshold and the display panel has entered the sleep mode, the control module controls the display panel to enter a normal display mode from the sleep mode. 
         [0008]    A portable device is provided. The portable device includes: an ambient light sensor, a control module, and an application module. The ambient light sensor is configured to detect ambient light around the portable device to generate a first sensing signal. The control module is configured to gather the first sensing signal from the ambient light sensor. The application module is for executing an application to generate display content to be displayed on a display panel. When the control module determines the first sensing signal is smaller than a first threshold, the control module controls the display panel to enter a sleep mode. When the control module determines the first sensing signal is larger than a second threshold and the display panel has entered the sleep mode, the control module controls the display panel to enter a normal display mode from the sleep mode. 
         [0009]    A computer-implemented method for use in a portable device is provided. The method includes the steps of: utilizing an ambient light sensor of the portable device to detect ambient light around the portable device to generate a first sensing signal; determining whether the first sensing signal is smaller than a first threshold; when it is determined that the first sensing signal is smaller than the first threshold, controlling a display panel of the portable device to enter a sleep mode; determining whether the first sensing signal is larger than a second threshold when the display panel has entered the sleep mode; and when it is determined that the first sensing signal is larger than the second threshold and the display panel has entered the sleep mode, controlling the display panel to enter a normal display mode from the sleep mode. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a block diagram of a portable device in accordance with an embodiment of the invention; 
           [0012]      FIG. 2  is a block diagram of a portable device in accordance with another embodiment of the invention; and 
           [0013]      FIG. 3  is a state diagram of display modes of the portable device in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
         [0015]      FIG. 1  is a block diagram of a portable device in accordance with an embodiment of the invention. The portable device  100  includes a control module  110 , a display module  120 , and one or more sensors  130 . The sensors  130  may include an ambient light sensor (ALS)  131  which detects the ambient light of the environment, and optionally include a motion sensor  132  which is implemented by an accelerometer and a gyroscope. The control module  110  comprises one or more processors  111  (e.g. CPU or DSP) or microcontrollers (MCU) configured to analyze the sensing signal (e.g. sensor data) from the sensors  130 , and transmit a decision signal to the display module  120 . The display module  120  includes a display controller  121  and a display panel  122 . The display controller  121  is configured to control the display timing and power states of the display panel  120 , and the power states, for example, may be a normal display mode, a low-power display mode, a sleep mode, or a shutdown mode, based on the decision signal from the control module  110 . For example, the control module  110  is configured to execute a program code or an application to output display content to the display module  120 . Alternatively, the control module  110  and the sensors  130  can be integrated into a sensor hub. In some embodiments, the display controller  121  can be integrated into the control module  110 . 
         [0016]    The display panel  122  may be a transmissive display panel or a reflective display panel implemented by LCD or OLED technologies. The transflective display panel is a display panel that reflects and transmits light (i.e. transflective =transmissive &amp; reflective). Under bright illumination (e.g. when exposed to daylight), the transflective display panel acts mainly as a reflective display panel with the contrast being constant with illuminance. An auxiliary transmissive backlight is needed in the transflective display panel only in dim and dark ambient situations. Alternatively, the display panel  122  comprises a touch detection module for detecting touch events on the surface of the display panel  122 . In an embodiment, the portable device  100  is a wearable device that can be wearable on a user&#39;s wrist, upper arm, and/or leg, or may be attached to the user&#39;s clothing, and may have the functions of a wristwatch, a wearable display, and/or a portable media player. 
         [0017]    In an embodiment, a user may become less sensitive to the images displayed on the display panel  122  of the portable device  100  in a dim or dark environment, especially on a transflective display panel or a reflective display panel. Thus, a low-power mechanism can be applied on the display panel  122  to reduce power consumption. The control module  110  determines whether the sensing signal (e.g. the amount of ambient light) from the ambient light sensor is smaller than a first threshold. When the control module  110  determines that the sensing signal from the ambient light sensor is smaller than a first threshold, the control module  110  controls the display panel  122  to enter a sleep mode to reduce power consumption, or informs the display controller  121  to control the display panel  122  to enter the sleep mode . When the display panel  122  has entered the sleep mode, the control module  110  further determines whether the sensing signal from the ambient light sensor is larger than a second threshold. When the control module  110  determines that the sensing signal from the ambient light sensor is larger than the second threshold, the control module  110  controls the display panel  122  to enter the normal display mode, or informs the controller  121  of the display module  120  to control the display panel  122  to enter the normal display mode. Alternatively, the user may manually awaken the display panel  122  by some specific operations, such as pressing hardware buttons or software icons of the portable device  100 , or performing a gesture on the display panel  122 , but the invention is not limited thereto. 
         [0018]      FIG. 2  is a block diagram of a portable device in accordance with another embodiment of the invention. The portable device  200  includes a control module  210 , a display module  220 , sensors  230 , and an application module  240 . The sensors  230  may include an ambient light sensor (ALS) which detects the ambient light of the environment, and optionally include a motion sensor such as an accelerometer. The control module  210  comprises one or more processors  211  configured to analyze the sensing signal (e.g. sensor data) from the sensors  230 , and transmit a decision signal to the display module  220 . Depending on the desired configuration, the processors  211  can be of any type, including a microprocessor, a microcontroller, or a digital signal processor. The display module  220  includes a display controller  221  and a display panel  222 . The display controller  221  is configured to control the display timing and the power mode of the display panel  220 , such as a normal mode, or a low-power mode, based on the decision signal from the control module  210 . The application module  240  is configured to generate the display content and setup the display mode of the display panel  222  of the display module  220 , such as a normal display mode or a low-power display mode. The display panel  222  may be a transflective display panel or a reflective display panel implemented by LCD or OLED technology. In some embodiments, the display controller  221  can be integrated into the control module  210 . 
         [0019]    The application module  240  provides an environment for executing applications that utilize the display panel  222  to display content of the applications. For example, the application module  240  may comprise a processor  241 , and a memory unit  242 . For example, the processor  241  may be a central processing unit (CPU) or a digital signal processor (DSP). Depending on the desired configuration, the memory unit  242  can be of any type, including volatile memory (such as RAM) and non-volatile memory (such as ROM, flash memory). The memory unit  242  can include an operating system, one or more applications, and program data. The processor  241  may execute an application stored in the memory unit  242 , and determine whether to switch the display panel  222  between a normal display mode, a low-power display mode, and a sleep mode. For example, the executed application may use different color depth in the normal display mode and the low-power display mode, such as using 8-bit color depth in the normal display mode and 1-bit color depth in the low-power display mode. In addition, the executed application may apply different user interfaces in the normal display mode and the low-power display mode, such as applying simple icons or a lower resolution in the low-power display mode. 
         [0020]    In an embodiment, the sensors  230  include both the ambient light sensor  231  and the motion sensor  232 . The control module  210  determines whether the first sensing signal, e.g. amount of ambient light, from the ambient light sensor  231  is smaller than a first threshold and the second sensing signal, e.g. amount of motion, from the motion sensor  232  is smaller than a second threshold. When the control module  210  determines that the first sensing signal from the ambient light sensor is smaller than a first threshold and the second sensing signal from the motion sensor  232  is smaller than a second threshold, the control module  210  controls the display panel  222  to enter the sleep mode to reduce power consumption. When the display panel  222  has entered the sleep mode, the control module  210  further determines whether the first sensing signal from the ambient light sensor  231  is larger than a third threshold or the second sensing signal is larger than a fourth threshold. When the control module  210  determines that the first sensing signal from the ambient light sensor  231  is larger than the third threshold or the second sensing signal is larger than the fourth threshold, the control module  210  awakens the display panel  222  to enter the normal display mode from the sleep mode. 
         [0021]    For example, the control module  210  controls the display panel  222  to enter the sleep mode when the portable device  100  is in a dim or dark environment (i.e. the ambient light is weak) and is likely stationary or slightly moving (i.e. a small amount of motion). When the user is wearing the portable device and entering a bright environment, the control module  210  awakens the display panel  222  to enter the normal mode from the sleep mode. Alternatively, when the portable device is moving strenuously (e.g. a large amount of motion), the control module  210  also awakens the display panel  222  to enter the normal mode from the sleep mode. In addition, the user may manually awaken the portable device to enter the normal mode from the sleep mode by performing specific operations, such as pressing a hardware button, a software icon, a touch or a gesture on the portable device  200 , but the invention is not limited thereto. 
         [0022]    In one embodiment, the portable device  200  is a wearable device. For example, the portable device  200  may be a smart watch or a smart wristband, and the portable device  200  may further include a strap, a wristband, or a bracelet (not shown in  FIG. 2 ). It should be noted that the portable device  200  may be in any form of wearable accessories equipped with a transflective display panel or a reflective display panel, and the invention is not limited to the aforementioned portable devices. For example, the portable device  200  can be wearable on a user&#39;s wrist, upper arm, and/or leg, or may be attached to the user&#39;s clothing, and may have the functions of a wristwatch, a wearable display, and/or a portable media player. 
         [0023]      FIG. 3  is a state diagram of display modes of the portable device in accordance with an embodiment of the invention. In state  310 , the display panel  222  is in a normal display mode. In branch  311 , when the display controller  221  and the application module  240  are informed to signal the display panel  222  to enter the low-power display mode (e.g. in a dim environment) from the normal display mode, the application module  240  may change the display content to be displayed on the display panel  222  in the low-power display mode. In state  320 , the display panel  222  is in the low-power display mode. For example, since the user becomes less sensitive to the displayed images on the display panel  222  in a dim environment, the application module  240  may use 1-bit color depth in the red, green, and blue color channels to reduce the updating and/or refreshing power of the display panel  222 , so that the power consumption can be significantly reduced in the low-power display mode. For example, the refresh rate of display panel  222  can be reduced to 30 Hz from 60 Hz, and the resolution of the display panel can be reduced to the quarter HD resolution (e.g. 960×540) from a full HD resolution (e.g. 1920×1080). For one having ordinary skill, it will be appreciated that the invention is not limited to the aforementioned refresh rate and resolution. 
         [0024]    In branch  312 , when the display panel  222  is in the low-power display mode and the portable device  200  has entered a bright environment, the display controller controls the display panel  222  to enter the normal display mode from the low-power display mode (branch  312 ). In state  330 , the display panel  222  is in the sleep mode. In branch  321 , when the portable device  200  is in a dark environment, the display controller  221  is informed to control the display panel  222  to enter the sleep mode, and the display controller  221  may control the display panel  222  to enter the sleep mode from the low-power display mode. Contrarily, when the display panel  222  is in the sleep mode and the portable device  200  has entered a dim environment, the display controller  221  may control the display panel to enter the low-power display mode from the sleep mode (branch  322 ). 
         [0025]    For example, during the transition between the normal display mode (state  310 ) and the sleep mode (state  330 ), the display controller  221  and the application module  240  may control the display panel  222  to enter the low-power display mode (state  320 ). In the low-power display mode, the application module  240  further adaptively controls the display content to fit the low-power display mode, respectively. The details can be referred to in the aforementioned embodiments. Furthermore, the transition of states in  FIG. 3  can be simplified to state  310  and state  320 . State  320  indicates that the display panel  222  is in a low-power mode, where the low-power mode indicates a low-power display mode, a sleep mode, or a power down mode. 
         [0026]    While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.