Road sign device and spontaneously emitted light sign system used for the device

A self-luminous marking system which comprises:

• a first LED which emits light when a quantity of light in a road environment is less than a predetermined level;
• a battery for supplying a power to the first LED;
• a drive circuit for controlling a drive of the first LED;
• a second LED utilized without application of voltage so as to generate an electromotive force in response to an incident light;
• a light quantity discrimination circuit which determines, based on the electromotive force generated by the second LED, whether the quantity of light in the road environment is less than the predetermined level;
• and
• a switch circuit which controls an operation of the drive circuit, based on a result determined by the light quantity discrimination circuit.

A self-luminous marking system which comprises:

• a first LED which emits light when a quantity of light in a road environment is less than a predetermined level;
• a solar battery and a condenser element for supplying a power to the first LED;
• a drive circuit for controlling a drive of the first LED;
• a second LED utilized without application of voltage so as to generate an electromotive force in response to an incident light;
• a light quantity discrimination circuit which determines, based on the electromotive force generated by the second LED, whether the quantity of light in the road environment is less than the predetermined level;
• and
• a switch circuit which controls an operation of the drive circuit, based on a result determined by the light quantity discrimination circuit.

A road marking device which comprises:

• a tubular, bottomed casing which has an open top end;
• a cover mounted over an opening in the casing and having a window;
• a self-luminous marking system composed of a power source housed in the casing, an illuminant which emits light by receiving a power supplied from the power source, and a circuit for driving the illuminant;
• and
• a transparent element which transmits and outwardly radiates the light emitted from the illuminant,
• wherein the transparent element is fixed between the cover and the casing which cooperatively hold a periphery of the transparent element, with a part of the transparent element protruding outwardly from the window in the cover,
• wherein the self-luminous marking system comprises:
• a battery as the power source;
• a first LED which emits light by receiving a power supplied from the battery, when a quantity of light in a road environment is less than a predetermined level;
• a drive circuit for controlling a drive of the first LED;
• a second LED utilized without application of voltage so as to generate an electromotive force in response to an incident light;
• a light quantity discrimination circuit which determines, based on the electromotive force generated by the second LED, whether the quantity of light in the road environment is less than the predetermined level;
• and
• a switch circuit which controls an operation of the drive circuit, based on a result determined by the light quantity discrimination circuit.