Patent ID: 6614409
Filing Date: 2003-09-02
Classification: A61F

Abstract:
A glare shielding device for a welding helmet, comprising:a liquid crystal panel; a solar battery circuit for converting light into an electrical energy to output a first output voltage for maintaining driving of a liquid crystal of the liquid crystal panel and a second output voltage for activating the liquid crystal at initial state of operation of the liquid crystal; a charging circuit for charging the first output voltage to provide a driving voltage; an oscillator circuit for generating an oscillating signal in response to the second output voltage; a high-voltage amplifier for charge-pumping the driving voltage in response to the oscillator circuit to generate a high voltage; a regulator for regulating the high voltage to generate a stable driving voltage; an activation voltage generator for generating a liquid crystal activation voltage in response to the oscillating signal; a driving circuit power controller for generating a ground voltage by being switched from a standby mode to a driving mode in response to a light detecting signal, and for maintaining a floating state by being switched from the driving mode to the standby mode in response to a power off controlling signal; a light detector for detecting a welding light using the second output voltage as a power source, and for outputting the light detection signal using the driving voltage as a power source; a high-frequency detector for detecting a high-frequency generated during a welding process using the light detection signal as a power source, and for outputting a high-frequency detection signal using the liquid crystal driving control signal as a power source; a liquid crystal activating portion for activating the liquid crystal panel using a minus voltage between the high voltage and the liquid crystal activation voltage in response to the light detection signal, and for maintaining an activation action during a predetermined period in response to the activation controlling signal; a liquid crystal driving portion for driving the liquid crystal panel using a minus voltage between the liquid crystal driving voltage and a ground voltage in response to the oscillator circuit; and a controller for working in response to the light detection signal, for generating the activation controll signal during an initial activation time in response to the high-frequency detection signal, for generating the driving control signal after the initial activation time passes, for stopping generating the driving control signal and generating the power off control signal and performing the standby mode when the light detection signal and the high-frequency detection signal does not exist; and a temperature detector for detecting ambient temperature of the liquid crystal panel to lower the liquid crystal activation voltage when the ambient temperature is below about 0Â° C., whereby rapidly activating the liquid crystal panel.