Patent ID: 7821489

Claim:
A data processing apparatus comprising: a backlight unit for emitting backlight; a liquid crystal display unit for displaying text data, the liquid crystal display unit being able to operate in a transparent display mode for transmitting the backlight and a reflection display mode for reflecting outside light; and a text data input unit for entering text data, wherein the backlight unit is turned off and the liquid crystal display unit enters into the reflection display mode when entry of the text data is absent for a first predetermined period of time in the transparent display mode, wherein the text data is continuously displayed during a transition from the transparent display mode to the reflection display mode, and during a transition from the reflection display mode to the transparent display mode, wherein, when entry of the text data is absent for a second predetermined period of time, the data processing apparatus enters a power supply stop mode, in which a power supply is disconnected from the liquid crystal display unit, and a sign is displayed on the liquid crystal display unit indicating that the data processing apparatus is in the power supply stop mode, wherein the sign which is displayed on the liquid crystal display unit comprises text data; and wherein the display of the sign is maintained on the liquid crystal display unit after the power supply is disconnected from the liquid crystal display unit.