Method of controlling display brightness of portable information device, and portable information device

• US 6,967,647 B2
• Filed: 01/02/2003
• Issued: 11/22/2005
• Est. Priority Date: 01/02/2003
• Status: Active Grant

• Current Assignee: Fujitsu Frontech Limited (Fujitsu Limited), Fujitsu Limited
• Original Assignee: Fujitsu Frontech Limited (Fujitsu Limited), Fujitsu Limited
• Inventors: Nokiyama, Takayuki
• Primary Examiner(s): Bella, Matthew C.
• Assistant Examiner(s): Sajous, Wesner
• Application Number:
  US10/335,152
• Publication Number:
  US 20040130556A1
• Time in Patent Office: 1,055 Days
• Field of Search: 345/617, 345/204, 345/207, 345/209, 345/210, 345/211, 345/84, 345/87, 345/95, 345/96, 345/601, 345/549, 345/77
• US Class Current: 345/204
• CPC Class Codes: G01R 31/3646 for indicating electrical conditions or variables, e.g. visual or audible indicators
• CPC Class Codes: G09G 2310/0237 Switching ON and OFF the backlight within one frame
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H04W 52/027 by controlling a display operation or backlight unit
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A battery voltage detector detects a voltage of a battery, a battery alarm voltage detector detects whether the voltage of the battery has dropped to a battery alarm voltage, a near-battery alarm voltage detector detects whether the voltage of the battery has dropped to a near-battery alarm voltage, and a display brightness control unit decreases the brightness of a display unit if the near-battery alarm voltage detector detects that the voltage of the battery has dropped to a near-battery alarm voltage.

Claims

1. An apparatus for controlling brightness of a display unit of a portable information device, the portable information device having a battery for supplying power to at least the display unit, the apparatus comprising:

a battery voltage detecting unit that detects a voltage of the battery;

a control unit that controls the brightness of the display unit based on the voltage detected by the battery voltage detecting unit; and

an estimating unit that estimates a voltage drop in the voltage detected by the battery voltage detecting unit in response to an electrical connection of a device to the portable information device,

wherein the control unit controls the brightness of the display unit based on the voltage drop estimated by the estimating unit,

the apparatus further comprising a memory that stores a first table of voltages of devices and name of the devices that are electrically connectable to the portable information device in a correlation form,

wherein the estimating unit estimates the voltage drop based on the first table.

2. A method of controlling brightness of a display unit of a portable information device, the portable information device having a battery for supplying power to at least the display unit and a control unit for controlling the brightness of the display unit, the method comprising the steps of:

detecting a voltage of the battery;

controlling the brightness of the display unit based on the detected battery voltage; and

estimating a voltage drop in the detected voltage in response to an electrical connection of a device to the portable information device,

wherein at the step of controlling the brightness of the display unit is controlled by the control unit based on the estimated voltage drop, and

wherein at the step of estimating the voltage drop is estimated based on a first table that stores voltages of devices and names of the devices that are electrically connectable to the portable information device in a correlation form.