Abstract: An optical system affixed to an electronic apparatus is provided, including a first optical module, a second optical module, and a third optical module. The first optical module is configured to adjust the moving direction of a first light from a first moving direction to a second moving direction, wherein the first moving direction is not parallel to the second moving direction. The second optical module is configured to receive the first light moving in the second moving direction. The first light reaches the third optical module via the first optical module and the second optical module in sequence. The third optical module includes a first photoelectric converter configured to transform the first light into a first image signal.

Abstract: A method for backing up data stored in a mobile electronic device is disclosed. The claimed method includes checking a plurality of data sets stored in the mobile electronic device according to a first predetermined rule to determine whether the data sets have been backed up into a remote storage unit; and processing at least one of the data sets that has not been backed up into the remote storage unit according to a second predetermined rule. The method of the present invention improves the security of mobile electronic devices without requiring users to perform complicated operations manually.

Abstract: A ground detector includes a detecting circuit formed of a polarity test circuit, a voltage dropping and rectifying circuit, a grounding test circuit and an alarm device, wherein the polarity test circuit leads in AC power supply and tests the polarity of its power wires so as to discriminate the standard zero potential circuit of the earth wire or neutral wire for grounding test reference; the voltage dropping and rectifying circuit converts lead-in AC power supply into DC power supply for working of the grounding test circuit; the grounding test circuit leads in the zero potential wire which is identified by the polarity test circuit, and compares its potential with the test circuit, so as to determine the grounding condition of the grounding bus, and to drive the alarm device when an error grounding of the rounding bus is detected, causing the alarm to output an audio alarm signal.