Data processing apparatus

Abstract

A data processing apparatus has a first processing unit for processing an input data, a second processing unit responsive to the data processed by the first processing unit for executing a processing dependent on the data and producing a display data, and a display unit having a display drive unit and a display device for displaying the display data. The second processing unit is selectively inactivated and activated under control of the first processing unit to reduce power consumption in the second processing unit. The display drive unit is also selectively inactivated and activated under control of the first processing unit to reduce power consumption in the display unit. The display device has a memory function that maintains its display image even when supply of a display drive signal from the display drive unit is stopped, so that a latest image before inactivation of the second processing unit and/or the display drive unit for power consumption reduction is visible by an operator during the inactivated and low power consumption state of the apparatus.

1 - 7 . (canceled)  
   
   
       8 . A portable data processing apparatus comprising: 
 a liquid crystal display unit;    a data input unit operable to input external data into said portable data processing apparatus; and    a control unit operable to detect whether a data entry from said data input unit is absent for a predetermined amount of time,    wherein, when data entry from said data input unit is absent for the predetermined time or longer, said control unit stops a supply of power to said liquid crystal display unit, and after stopping the supply of power to said liquid crystal display unit, said control unit shuts off a supply of power to said portable data processing apparatus.    
   
   
       9 . A portable data processing apparatus according to  claim 8 , further comprising a back light.  
   
   
       10 . A portable data processing apparatus according to  claim 9 , wherein said control unit stops a supply of power to said back light before stopping the supply of power to said liquid crystal display unit.  
   
   
       11 . A portable data processing apparatus according to  claim 8 , wherein said liquid crystal display unit is a transmission/reflection combination type liquid crystal display unit.