Abstract:
A method and system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel are introduced. The method includes configuring the electronic device with a first threshold level and a second threshold level, wherein the first threshold level and the second threshold level are voltage levels or current levels; attaching the thin-film solar panel to a casing of the electronic device for enabling the electronic device to convert an external light into a transformed voltage or current; and determining whether the transformed voltage or current lies between the first threshold level and the second threshold level to decide whether to allow the display screen to operate at an existing brightness level thereof continuously. The method and system enable the electronic device to receive the external light for supplementing power supple and sense the external light for adjusting power level.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 101107494 filed in Taiwan, R.O.C. on Mar. 6, 2012, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to methods and systems for rendering electronic devices energy-efficient, and more particularly, to a method and system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel capable of supplying power, charging, and detection. 
     BACKGROUND OF THE INVENTION 
     In recent years, changes in lifestyle leads to wide use of electronic devices, such as notebook computers, tablet computers, smartphones, e-books, personal digital assistants (PDA), and multimedia players. 
     The aforesaid electronic devices are powered by batteries. Hence, what is important to the aforesaid electronic devices is the data related to battery power level and battery sustainability. 
     According to the prior art, engineers enable an electronic device to operate for a longer period of time before its battery runs out of power, by taking the following measures: increasing the battery capacity, making the electronic device more power-saving, or providing an additional auxiliary power source to the electronic device. 
     Electronic devices can be rendered power-saving through power management. The most power-consuming component of a display-enabled electronic device is a display screen. Take a liquid crystal display screen as an example, the liquid crystal display screen comprises liquid crystal cells and a backlight unit. The backlight unit generates light for lighting up the liquid crystal cells in operation. If the liquid crystal cells in operation are not lit up, users cannot read what is displayed on the liquid crystal cells. In general, the backlight unit is the most power-consuming components of a display-enabled electronic device. 
     Known ways of power management of a display-enabled electronic device are of two categories, namely hardware-based power management and software-based power management. The hardware-based power management involves detecting ambient light with a light sensor (such as a photoresistor), increasing the light intensity of the light generated from the backlight unit when strong light intensity of ambient light is detected to allow the user to read an image displayed on the liquid crystal cells, and decreasing the light intensity of the light generated from the backlight unit when weak light intensity of ambient light is detected to save power. 
     Furthermore, take a smartphone as an example, the speaker is equipped with a light sensor whereby the backlight unit is shut down as soon as the user starts a conversation on the smartphone. The software-based power management involves detecting the use status of the electronic device and instructing the electronic device to enter a standby mode, a hibernation mode, or a shutdown mode upon detection that the electronic device is idle. 
     However, the aforesaid prior art has its own drawbacks. First, the additional hardware (such as a light sensor) also consumes power to the detriment of power saving. Second, although the software-based power management saves power by determining the point in time to start or shut down the backlight unit, it does not offer a power-saving solution to the backlight unit in operation. 
     SUMMARY OF THE INVENTION 
     It is an objective of the present invention to provide a method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel. The method enables the electronic device to adjust the display screen brightness thereof automatically in accordance with an external light so as to effectuate power saving. 
     Another objective of the present invention is to provide a system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel. Given the system, an electronic device with a display screen is rendered energy-efficient. 
     In order to achieve the above and other objectives, the present invention provides a method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel. The method is applicable to an electronic device having a display screen and a casing. The method comprises the steps of: configuring the electronic device with a first threshold level and a second threshold level, the first threshold level being higher than the second threshold level, wherein the first threshold level and the second threshold level are at least one of a voltage level and a current level; attaching the thin-film solar panel to the casing for enabling the electronic device to convert an external light into a transformed voltage or current; and determining whether the transformed voltage or current lies between the first threshold level and the second threshold level to determine whether to supply the transformed voltage or current to the electronic device continuously so as to maintain a brightness of the display screen. 
     In order to achieve the above and other objectives, the present invention provides a system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel. The system is applicable to an electronic device having a display screen. The system comprises a casing, a thin-film layer, and a control unit. The casing holds the display screen. The thin-film layer is disposed at at least a portion of the casing and adapted to receive an external light for performing photoelectrical conversion to generate the transformed voltage or current. The control unit is configured with a first threshold level and a second threshold level, connected to the thin-film layer, and adapted to control a brightness of the display screen in accordance with a result of comparison of the transformed voltage or current with the first threshold level and the second threshold level, wherein the first threshold level and the second threshold level is in form of at least one of a voltage and a current. 
     Compared with the prior art, the present invention provides a method and system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel. The method and system of the present invention are effective in supplying power, charging, and detection by means of a single thin-film solar panel (also defined as a solar energy thin-film layer according to the present invention) disposed at a casing of the electronic device, and thus power management can be efficiently performed on the electronic device. The solar energy thin-film layer receives an external light (such as sunlight, indoor light, or outdoor light), generates a voltage or current to be applied to the electronic device, and assesses the voltage level or the current level so as to determine whether to supply the voltage or the current directly to the electronic device and whether to store the voltage-derived power or the current-derived power in the battery for undergoing charging. 
     The method and system of the present invention are effective in determining whether an electronic device has to control (for example, maintain, increase, or decrease the brightness of) a power-consuming module (such as, a display screen) thereof according to the voltage level or current level in order to save energy. Accordingly, the present invention provides a method and system for performing power management on an electronic device efficiently by means of a thin-film layer capable of photoelectrical conversion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Objectives, features, and advantages of the present invention are hereunder illustrated with specific embodiments in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a flow chart of a method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to an embodiment of the present invention; 
         FIG. 2  is a flow chart of the method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to another embodiment of the present invention; 
         FIG. 3  is a structural schematic view of a system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to an embodiment of the present invention; 
         FIG. 4(   a ) is a structural schematic view of a control unit in  FIG. 3 ; 
         FIG. 4(   b ) is a transfer characteristic curve of the control unit in  FIG. 3 ; and 
         FIG. 5  is a structural schematic view of the system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , there is shown a flow chart of a method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to an embodiment of the present invention. As shown in  FIG. 1 , the method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel is applicable to an electronic device having a display screen and a casing. The electronic device is a desktop computer, a tablet computer, a notebook computer, a smartphone, or any electronic apparatus having a display screen. 
     The process flow of the method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel starts with step S 11 . Step S 11  involves configuring the electronic device with a first threshold level FV and a second threshold level SV, with the first threshold level FV being higher than the second threshold level SV, wherein the first threshold level FV and the second threshold level SV are at least one of a voltage level and a current level. In an embodiment, a user or a manufacturer of the electronic device can configure the electronic device with the first threshold level FV and the second threshold level SV by means of software or hardware to suit the environment in which the electronic device operates. The software is an operating system, such as Apple&#39;s iPhone iOS, Google&#39;s Android, Microsoft&#39;s Windows mobile and Win 8. The hardware is a ready-only memory (ROM), an erasable memory, or a basic input/output system (BIOS). 
     For instance, in an embodiment, the electronic device is a notebook computer configured with the first threshold level FV set to a current of 20 mA and the second threshold level SV set to a current of 10 mA. 
     Step S 12  involves attaching a thin-film solar panel to the casing of the electronic device for enabling the electronic device to convert an external light EL into a transformed voltage or current TVI. The casing serves to enclose or package the display screen. The thin-film solar panel is an organic photovoltaic for absorbing the external light EL (such as sunlight, indoor light, or outdoor light). For example, particles within the organic photovoltaic absorb the energy of the external light EL and thus bring about charge motion, thereby generating a direct current (DC). The thin-film solar panel is attached to a portion of the surface of the casing, wherein the portion of the surface of the casing is of a small area or of a large area. Alternatively, the thin-film solar panel is attached to the display screen of the electronic device, wherein the thin-film solar panel is transparent and thus does not affect the performance of the display screen. Alternatively, the thin-film solar panel is attached to the display screen of the notebook computer. 
     Step S 13  involves determining whether the transformed voltage or current TVI lies between the first threshold level FV and the second threshold level SV to determine whether to supply power to the display screen of the electronic device continuously so as to maintain the brightness of the display screen. An affirmative determination causes step S 13  to be followed by step S 131 . A negative determination causes step S 13  to be followed by step S 132 . The determination process is carried out with a control unit of the electronic device, wherein the control unit is, for example, a self-contained control chip or a central processing unit (CPU). 
     Step S 131  involves maintaining the brightness of the display screen. 
     For instance, in the situation where the transformed voltage or current TVI manifests in the form of a transformed current of 15 mA, the transformed current of 15 mA lies between the first threshold level FV (such as 20 mA) and the second threshold level SV (such as 10 mA), and thus the brightness of the display screen remains unchanged. 
     Step S 132  involves determining whether the transformed voltage or current TVI is higher than or equal to the first threshold level FV. Go to Step S 133  when the determination is affirmative. Go to Step S 134  when the determination is negative. 
     Step S 133  involves maintaining or increasing the brightness of the display screen. 
     For instance, in the situation where the transformed voltage or current TVI manifests in the form of a transformed current of 30 mA, the transformed current of 30 mA is higher than the first threshold level FV (such as 20 mA), and thus the brightness of the display screen is maintained or increased. 
     Step S 134  involves reducing the brightness of the display screen to reduce power consumption. 
     For instance, in the situation where the transformed voltage or current TVI manifests in the form of a transformed current of 5 mA, the transformed current of 5 mA is lower than the second threshold level SV (such as 10 mA), and thus the brightness of the display screen is reduced. 
     Upon completion of step S 133  or step S 134 , the process flow of the method according to an embodiment of the present invention goes back to step S 11 , so as to enable ongoing adjustment of the brightness of the display screen of the electronic device in accordance with the transformed voltage or current TVI. 
     Referring to  FIG. 2 , there is shown a flow chart of the method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to another embodiment of the present invention. The method for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel is applicable to an electronic device having a display screen and a casing. In addition to the aforesaid steps S 11 ˜S 14 , the method further comprises step S 21 . Step S 21  involves transforming the transformed voltage or current TVI into a charging voltage or current CVI for charging the electronic device, or charging or supplying power to the electronic device with the transformed voltage or current TVI directly. 
     Referring to  FIG. 3 , there is shown a structural schematic view of a system  10  for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to an embodiment of the present invention. As shown in  FIG. 3 , the system  10  is applicable to an electronic device  4  with a display screen  2 . 
     The system  10  comprises a casing  12 , a thin-film layer  14 , and a control unit  16 . The display screen  2  is disposed at the casing  12 . The thin-film layer  14  is disposed at at least one portion of the casing  12  and adapted to receive an external light EL for performing photoelectrical conversion to generate the transformed voltage or current TVI. For example, the thin-film layer  14  comes in the form of an organic photovoltaic. In an embodiment, the thin-film layer  14  is disposed at an outer margin or an inner margin of the casing  12 . 
     The control unit  16  is configured with the first threshold level FV and the second threshold level SV, connected to the thin-film layer  14 , and adapted to control the display brightness of the display screen  2  in accordance with the result of comparison of the transformed voltage or current TVI with the first threshold level FV and the second threshold level SV. In this regard, it is defined that the first threshold level FV is higher than the second threshold level SV, and it is defined that the first threshold level FV and the second threshold level SV are at least one of a voltage and a current. In an embodiment, the control unit  16  comes in the form of a plurality of comparators or a microprocessor. 
     For instance, referring to  FIG. 4(   a ), in the situation where the control unit  16  is implemented in the form of comparators, in this embodiment, three comparators CMP 1 , CMP 2 , CMP 3  compare the transformed voltage or current TVI with the first threshold level FV and the second threshold level SV to generate three control signals CS 1 , CS 2 , CS 3 , respectively, for controlling the display brightness of the display screen  2 . 
     For instance, if the positive end of the comparator CMP 1  receives the transformed voltage or current TVI and the negative end of the comparator CMP 1  is configured with the first threshold level FV or the second threshold level SV, the comparator CMP 1  will output positive saturated voltage +V cc  for functioning as the control signal CS 1  when the comparison result indicates that the transformed voltage or current TVI (for example, in the form of a voltage) is higher than or equal to the first threshold level FV. Conversely, if the comparison result indicates that the transformed voltage or current TVI (for example, in the form of a voltage) is lower than or equal to the first threshold level FV, the comparator CMP 1  will output negative saturated voltage −V cc  for functioning as the control signal CS 1 . The above-mentioned applies to the comparators CMP 2 , CMP 3  too. 
     Referring to  FIG. 4(   b ), there is shown a transfer characteristic curve of the control unit  16  in  FIG. 3 , where the control unit  16  is configured with the first threshold level FV of 10V and the second threshold level SV of 5V. If the transformed voltage or current TVI (for example, in the form of a voltage) is higher than or equal to 10V, the control signal CS 3  will output positive saturated voltage +V cc . If the transformed voltage or current TVI (for example, in the form of a voltage) is lower than the first threshold level FV but higher than the second threshold level SV, the control signal CS 3  will output a zero voltage. If the transformed voltage or current TVI (for example, in the form of a voltage) is lower than or equal to 5V, the control signal CS 3  will output negative saturated voltage −V cc . The above-mentioned is illustrative rather than restrictive of the present invention, and thus the present invention is not limited to implementing the control unit  16  in the form of a plurality of comparators. 
     Depending on the result of comparison, the control signal CS takes care of three scenarios. The control signal CS serves to control the maintenance or enhancement of the brightness of the display screen as soon as the control unit determines that the transformed voltage or current TVI is higher than or equal to the first threshold level FV. The control signal CS serves to control the maintenance of the brightness of the display screen as soon as the control unit determines that the transformed voltage or current TVI lies between the first threshold level FV and the second threshold level SV. The control signal CS serves to control the reduction of the brightness of the display screen as soon as the control unit determines that the transformed voltage or current TVI is lower than or equal to the second threshold level SV. 
     Referring to  FIG. 5 , there is shown a structural schematic view of the system  10  for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel according to another embodiment of the present invention. In the another embodiment shown in  FIG. 5 , the system  10  is applicable to the electronic device  4  with the display screen  2 . In the another embodiment shown in  FIG. 5 , in addition to the casing  12 , the thin-film layer  14 , and the control unit  16 , the system  10  further comprises a battery unit  18 . The battery unit  18  is connected to the thin-film layer  14 . The thin-film layer  14  is where the battery unit  18  is charged with the transformed voltage or current TVI. 
     The thin-film layer  14  further comprises a voltage transforming unit  142  for transforming the transformed voltage or current TVI into a charging voltage or current CVI and sending the charging voltage or current CVI to the control unit  16  for determining whether to adjust the display brightness of the display screen  2 . In an embodiment, the battery unit  18  is connected to the thin-film layer  14  and charged with the charging voltage or current CVI generated from the thin-film layer  14 . 
     The present invention provides a method and system for adjusting power supply and display screen brightness of an electronic device with a thin-film solar panel. The method and system of the present invention are effective in supplying power, charging, and detection by means of a single thin-film solar panel (also defined as a solar energy thin-film layer according to the present invention) disposed at a casing of the electronic device, and thus power management can be efficiently performed on the electronic device. The solar energy thin-film layer receives an external light, generates a voltage or current to be applied to the electronic device, and assesses the voltage level or the current level so as to determine whether to supply the voltage or the current directly to the electronic device and whether to store the voltage-derived power or the current-derived power in the battery for undergoing charging. The method and system of the present invention are effective in adjusting the display brightness of the display screen of the electronic device according to the power level. 
     Accordingly, the present invention provides a method and system for performing power management on an electronic device efficiently by means of a thin-film layer capable of photoelectrical conversion. 
     The present invention is disclosed above by preferred embodiments. However, persons skilled in the art should understand that the preferred embodiments are illustrative of the present invention only, but should not be interpreted as restrictive of the scope of the present invention. Hence, all equivalent modifications and replacements made to the aforesaid embodiments should fall within the scope of the present invention. Accordingly, the legal protection for the present invention should be defined by the appended claims.