A vehicle rear windshield structure includes a first rear windshield, a second rear windshield, and a light shielding wall. A triggering device having a unique code stored therein is provided to the user. The buffer unit is connected between a first power supply or a voltage regulator and a second power supply to receive power supply, and outputs a signal having the same or inverted logic level as an input signal to an output terminal. The clock section provides a clock communication path between the baseband processing module and the RF circuit. The ink absorbed into the cleaning member is removed again using a second pressing unit or a cleaning roller, and hence the absorbency of the cleaning member can be maintained and the replacement cycle can be extended. In the method the pulse-width-modulated light-emitting diode current is detected and a current sensor signal is derived and fed to a microprocessor, which outputs a drive signal for the pulse-width-modulation and for the setting of the light-emitting diode voltage applied to the light-emitting diodes, depending on the detected current sensor signal.