Digital Photo Frame with Power Saving Function and Related Power Saving Method

• US 20090160541A1
• Filed: 08/06/2008
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Wistron Corporation
• Original Assignee: Wistron Corporation
• Inventors: Liu, Wei-Lun, Huang, Jheng-Bin, Shih, Hsin-Hui, Wu, Wen-Chin, Li, Chia-Hsien, Lu, Huang-Ping
• Granted Patent: US 8,436,804 B2
• Time in Patent Office: Days
• US Class Current: 327/544
• CPC Class Codes: G06F 1/3228 Monitoring task completion, e.g. by use of idle timers, stop commands or wait commands
• CPC Class Codes: G06F 1/3231 Monitoring the presence, absence or movement of users
• CPC Class Codes: G06F 1/3246 by software initiated power-off
• CPC Class Codes: G06F 1/3265 Power saving in display device
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: G09G 2354/00 Aspects of interface with display user
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 5/10 Intensity circuits
• CPC Class Codes: H04N 1/00885 Power supply means, e.g. arrangements for the control of power supply to the apparatus or components thereof
• CPC Class Codes: H04N 1/00891 Switching on or off, e.g. for saving power when not in use H04N1/00896 takes precedence
• CPC Class Codes: H04N 1/00896 using a low-power mode, e.g. standby
• CPC Class Codes: H04N 1/00904 Arrangements for supplying power to different circuits or for supplying power at different levels H04N1/00896 takes precedence
• CPC Class Codes: H04N 2201/0089 Image display device
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A digital photo frame having power saving functions includes a display panel, a power generation unit for switching a system power according to a power control signal, a user detection unit installed on the display panel for detecting whether a user exists within a specific range to generate a user detection signal, a central processing unit for adjusting backlight intensity of the display panel when the system power is provided by the power generation unit according to the user detection signal and for generating a power switch-off signal when the backlight intensity of the display panel is turned off according to the user detection signal, and a power control unit for generating the power control signal to switch off the system power when the backlight intensity of the display panel is adjusted to be switched off according to the power switch-off signal.

Claims

1. A digital photo frame with power saving functions comprising:

a display panel;

a power generation unit for providing system power and switching the system power according to a power control signal;

a user detection unit, installed in the display panel, for detecting presence of a user within a specific range to generate a user detection signal;

a central processing unit, coupled to the power generation unit and the user detection unit, for dimming backlight intensity of the display panel according to the user detection signal when the system power is provided by the power generation unit and for generating a power switch-off signal according to the user detection signal when the backlight intensity of the display panel is dimmed to be off; and

a power control unit, coupled to the power generation unit and the central processing unit, for generating the power control signal to control the power generation unit to switch off the system power according to the power switch-off signal when the backlight intensity of the display panel is dimmed to be off.

2. The digital photo frame of claim 1 further comprises:

a clock generator, coupled to the power control unit and the central processing unit, for generating a clock trigger signal according to a predetermined time;

a power switch, coupled to the power control unit and the central processing unit, for generating a power trigger signal according to a user control signal; and

a plurality of functional buttons, coupled to the central processing unit, for generating a plurality of button trigger signals to control the central processing unit to execute a plurality of corresponding functions according to a plurality of user control signals, respectively.

3. The digital photo frame of claim 2, wherein the power control unit further generates the power control signal to control the power generation unit to switch on the system power again according to the user detection signal, the clock trigger signal, the power trigger signal or the plurality of button trigger signals when the backlight intensity of the display panel is dimmed to be off.

4. The digital photo frame of claim 3, wherein the user detection unit is a sensor selected from a sensor group comprising a passive infrared sensor, a photo-resistor or an ultrasonic sensor.

5. The digital photo frame of claim 4, wherein the user detection unit further comprises a time delay device sampling the user detection signal outputted by the user detection unit every specific time interval and outputs corresponding sampling results to the central processing unit and the power control unit for preventing abnormal operation.

6. The digital photo frame of claim 5, wherein the power generation unit comprises:

a rechargeable battery for providing the system power of the digital photo frame for keeping normal operation; and

a power transistor switch for controlling electrical coupling between the rechargeable battery and the central processing unit according to the power control signal.

7. A method of saving power for a digital photo frame, the method comprising:

computing a first idle time of the digital photo frame according to a user trigger signal and determining whether the first idle time is greater than a first default value;

switching on a user detection unit when the first idle time is greater than the first default value;

computing a second idle time of the digital photo frame according to a user detection signal generated by the user detection unit or the user trigger signal and determining whether the second idle time is greater than a second default value;

switching off a backlight of a display panel on the digital photo frame when the second idle time is greater than the second default value;

computing a third idle time of the digital photo frame according to the user detection signal generated by the user detection unit or the user trigger signal and determining whether the third idle time is greater than a third default value; and

switching off a system power of the digital photo frame when the third idle time is greater than the third default value.

8. The method of claim 7 further comprising:

generating a power-saving warning signal for reminding users that the digital photo frame has entered a power saving process when the first idle time is greater than the first default value.

9. The method of claim 8 further comprising:

switching on the system power of the digital photo frame and the backlight of the display panel again and switching off the user detection unit according to the user detection signal generated by the user detection unit or the user trigger signal after the system power of the digital photo frame is switched off.

10. The method of claim 9, wherein the user trigger signal comprises:

a clock trigger signal generated by a clock generator according to a predetermined time;

a power trigger signal generated by a power switch; and

a plurality of functional button trigger signals respectively generated by a plurality of functional buttons.

11. The method of claim 10, wherein the user detection signal is generated by the user detection unit upon detecting a user exists within a specific range.

12. The method of claim 7, wherein the user detection signal is generated by the user detection unit upon detecting a user exists within a specific range.

13. A method of saving power for a digital photo frame, the method comprising:

computing a first idle time of the digital photo frame according to a user trigger signal and determining whether the first idle time is greater than a first default value;

switching on a user detection unit and dimming backlight intensity of a display panel of the digital photo frame when the first idle time is greater than the first default value;

computing a second idle time of the digital photo frame according to a user detection signal generated by the user detection unit or the user trigger signal and determining whether the second idle time is greater than a second default value;

determining whether the backlight intensity of the display panel is dimmed to be off when the second idle time is greater than the second default value;

computing a third idle time of the digital photo frame according to the user detection signal generated by the user detection unit or the user trigger signal after the backlight intensity of the display panel is dimmed to be off and determining whether the third idle time is greater than a third default value; and

switching off a system power of the digital photo frame when the third idle time is greater than the third default value.

14. The method of claim 13 further comprising:

dimming the backlight intensity of the display panel again when the backlight of the display panel is not yet dimmed to be off.

15. The method of claim 14 further comprising:

switching on the system power of the digital photo frame and the backlight of the display panel again and switching off the user detection unit according to the user detection signal generated by the user detection unit or the user trigger signal after the system power of the digital photo frame is switched off.

16. The method of claim 15, wherein the user trigger signal comprises:

a clock trigger signal generated by a clock generator according to a predetermined time;

a power trigger signal generated by a power switch; and

a plurality of functional button trigger signals respectively generated by a plurality of functional buttons.

17. The method of claim 16, wherein the user detection signal is generated by the user detection unit detecting a user exists within a specific range.

18. The method of claim 13, wherein the user detection signal is generated by the user detection unit detecting a user exists within a specific range.