This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application for Power Saving of a Portable Computer Using Human Sensing Device earlier filed in the Korean Industrial Property Office on Apr. 7, 1998 and there duly assigned Serial No. 12255/1998.
The present invention relates to portable computers, and more particularly to a portable computer having a power saving function that reduces supply power consumed in a display device.
Compact and lightweight notebook and laptop computers have become increasingly popular due to their portability. These portable computers are typically powered by rechargeable batteries or alternatively by a power adapter which can be connected to an AC outlet. Often, it is desirable to operate the portable computers for lengthy periods of time in environments where AC power is unavailable.
As a system level solution, most portable computer systems usually adopt a power saving and power management system as provided in Advanced Power Management (APM) jointly developed by Intel (r) and Microsoft (r). This power management is to maximize available battery usage time. Basically, it automatically reduces the power consumption of parts of the computer currently not in use. The power management system provides various power saving function with the lapse of time set by the CMOS setup program, and manages the progress of power saving between full-on, doze, standby, and rest mode. The rest mode is the least power consumption level, which interrupts power supplies directed to microprocessor, display apparatus, hard disk drives, floppy disk drives, and other subsystems. Only supplied power is that with the subsystem which can restore the system to the full-on state.
Further, the power saving function may be performed by back-light timer with the lapse of time set by the CMOS setup program, which manages cut-off of power supply directed to a back-light unit of LCD display panel. When the system is not working for the preset time, the back-light unit of LCD display goes into power-off status. This power management is useful for portable computers having a LCD display panel to use less power while the system is running on battery power.
However, in actual computer using condition, when the portable computer is powered on and a computer work is proceeding, the work may be interrupted by some matter and the user may leave the portable computer without turning off power or having the computer system go into the rest mode of the power management. In this case, the battery power is still consuming while the user is leaving the portable computer. Further, if the system power down times of the above power management have been set with long time intervals, the power saving function may be ineffective in saving the battery power. This requires modification of the power down times in the power management setup to suit work conditions whenever required. Also, the adjustment process is inconvenient for the user and conversely the modified power saving function may be unsuitable for a specific computer work.
Thus, there is a need in the portable computer art a more effective and simple power saving function that can minimize unnecessary power consumption during the computer use regardless of the power management setup condition.
The present invention is intended to solve the prior art problems, and it is therefore an object of the invention to provide a portable computer which can perform an instant power saving function in response to absence of the computer user during use of the computer.
According to the present invention, the portable computer is provided with a sensing device which responds to absence of the computer user so that the computer system instantly goes into a power saving function that cuts off power directed to a back-light unit of the LCD display panel. A portable computer of the present invention comprises a sensor for sensing a computer user within the predetermined sensing range, said sensor being mounted in the housing of the flat panel display with facing the computer user, to produce a signal representative of absence of the user within the range; and a controller in response to said output signal of said sensor to produce a control signal which allows the supply power directed to the flat panel display to be interrupted.
The portable computer further comprises a basic input/output system (BIOS) which stores setup information regarding enabling/disabling the operation of said sensor. The sensor includes: a transmitter generating a sensing signal; and a receiver receiving the reflected sensing signal and responsive thereto outputting a signal representative of presence of the user.
Preferably, the sensing signal consists of ultrasonic wave or infrared rays. Further, the controller responds to the output signal representating presence of the user, and determines whether a user password flag has been set in the system BIOS and if the password has been set a command is sent to the BIOS, resulting in generation of a message requesting input of the user password.