Organic electroluminescent light emitting device for restoring normal operation after low-voltage errors

A light emitting device comprising:

• a direct-current power source circuit having positive and negative poles and operable to supply at least a certain current;
• a plurality of light emitting elements comprising first and second light emitting elements coupled in series and operable to emit light upon receiving a supply of direct-current current;
• and
• a direction inverting circuit including first, second, and third pairs of switching elements coupled in series between the power source positive and negative poles, the first light emitting element being connected between series contacts of the first and second pairs of switching elements, the second light emitting element being coupled between series contacts of the second and third pairs of switching elements,
• the direction inverting circuit effective to determine a direction of current allocated to each of said first and second light emitting elements and a direction of current applied to each of said first and second light emitting elements,
• wherein when a low-voltage error is detected in any of the plurality of light emitting elements, the direction inverting circuit applies a reverse voltage to the light emitting elements in which the low-voltage error has been detected, and
• wherein when a normal state of a light emitting element to which the reverse voltage has been applied is detected, the direction inverting circuit applies a forward voltage to the light emitting elements in which the normal state has been detected.

A light emitting device comprising:

• a direct-current power source circuit effective to supply at least a certain current;
• a plurality of light emitting elements effective to emit light upon receiving a supply of direct-current current;
• and
• a direction inverting circuit further comprising
• a plurality of switching elements effective to switch the direction of the current applied to the plurality of light emitting elements,
• a voltage detecting portion effective to detect the voltage of the plurality of light emitting elements,
• a direction inverting circuit controlling portion effective to provide one or more signals to turn on and off the plurality of switching elements based on the voltage of the plurality of light emitting elements detected by the voltage detecting portion, and
• one or more drive circuits, each drive circuit operable to drive a plurality of associated switching elements according to a signal from the direction inverting circuit controlling portion;
• the direction inverting circuit effective to determine a direction of current allocated to each light emitting element and a direction of current applied to each light emitting element,
• wherein when a low-voltage error is detected in any of the plurality of light emitting elements, the direction inverting circuit applies a reverse voltage to the light emitting elements in which the low-voltage error has been detected, and
• wherein when a normal state of a light emitting element to which the reverse voltage has been applied is detected, the direction inverting circuit applies a forward voltage to the light emitting elements in which the normal state has been detected.

A method of restoring normal operation to a light emitting device having a plurality of light emitting elements after the occurrence of a low-voltage error in one or more of the light emitting elements, the method comprising:

• (a) providing a supply of direct-current current to the plurality of light emitting elements;
• (b) detecting a voltage applied to each of the plurality of light emitting elements;
• (c) comparing each detected voltage to a predetermined voltage representative of a low-voltage error;
• (d) reversing the direction of the current provided to any light emitting element having a forward current flow upon detecting a voltage applied to said light emitting element less than or equal to the predetermined voltage;
• (e) reversing the direction of the current provided to any light emitting element having a reverse current flow upon detecting a voltage applied to said light emitting element greater than the predetermined voltage.

A method of restoring normal operation to a light emitting device having a plurality of light emitting elements after the occurrence of a low-voltage error in one or more of the light emitting elements, the method comprising:

• (a) providing a supply of direct-current current to the plurality of light emitting elements;
• (b) detecting a voltage applied to each of the plurality of light emitting elements;
• (c) comparing each detected voltage to a predetermined voltage representative of a low-voltage error;
• (d) reversing the direction of the current provided to any light emitting element having a forward current flow upon detecting a voltage applied to said light emitting element less than the predetermined voltage;
• (e) reversing the direction of the current provided to any light emitting element having a reverse current flow upon detecting a voltage applied to said light emitting element greater than or equal to the predetermined voltage.