Display Apparatus

Abstract

A display apparatus, that includes current driving type luminescent elements, has a driving system that takes the conduction types of TFTs to control the emission of the luminescent elements into consideration. In order to reduce driving voltage and improve display quality simultaneously, the arrangement is provided such that if the second TFT which performs the “on-off” function of the current for the luminescent element is of an N channel type, the potential of the common power supply line (“com”) is lowered below the potential of the opposite electrode (“op”) of the luminescent element to obtain a higher gate voltage (“Vgcur”). In this case, if the first TFT connected to the gate of the second TFT is of a P channel type, when using the potential of the potential-holding electrode (“st”) at the “on” state as a reference, potentials of the scanning signal (“Sgate”) at the lower potential and the common power supply line (“com”) are rendered of the same polarities with respect to this potential of the potential-holding electrode (“st”). Therefore, the potential of the image signal (“data”) to turn “on” can be shifted within the range of the driving voltage in the display apparatus in the direction to reduce resistances at the “on” states of the first TFT and the second TFT to reduce driving voltage and improve display quality.

1 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the one second transistor is in an “on” state:   a potential of the one power supply line of the power supply lines being higher than a potential of the opposite electrode, and a potential of a gate electrode of the one second transistor of the second transistors being higher than or being equal to the potential of the opposite electrode.   
     
     
         2 . The electro-luminescent apparatus of  claim 1 ,
 wherein the second transistors are P-channel type.   
     
     
         3 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element of the luminescent elements being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the one second transistor is in an “off” state:   a potential of the one power supply line of the power supply lines being higher than a potential of the opposite electrode, and a potential of a gate electrode of the one second transistor of the second transistors being higher than or being equal to the potential of the opposite electrode.   
     
     
         4 . The electro-luminescent apparatus of  claim 3 ,
 wherein the second transistors are P-channel type.   
     
     
         5 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element of the luminescent elements being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the one second transistor is in an “on” state:   a potential of the one power supply line of the plurality of power supply lines being lower than a potential of the opposite electrode, and a potential of a gate electrode of the one second transistor of the second transistors being lower than or being equal to the potential of the opposite electrode.   
     
     
         6 . The electro-luminescent apparatus of  claim 5 ,
 wherein the second transistors are N-channel type.   
     
     
         7 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element of the luminescent elements being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the one second transistor is in an “off” state:   a potential of the one power supply line of the plurality of power supply lines being lower than a potential of the opposite electrode, and a potential of a gate electrode of the one second transistor of the second transistors being lower than or being equal to the potential of the opposite electrode.   
     
     
         8 . The electro-luminescent apparatus of  claim 7 ,
 wherein the second transistors are N-channel type.   
     
     
         9 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element of the luminescent elements being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the second transistor is in an “on” state:   a potential of the one power supply line of the power supply lines being higher than a potential of the opposite electrode, and a potential of the data signal to be supplied to the data line connected to the one second transistor of the second transistors being higher than or being equal to the potential of the opposite electrode.   
     
     
         10 . The electro-luminescent apparatus of  claim 9 ,
 wherein the second transistors are P-channel type.   
     
     
         11 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element of the luminescent elements being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the one second transistor is in an “off” state:   a potential of the one power supply line of the power supply lines being higher than a potential of the opposite electrode, and a potential of the data signal to be supplied to the data line connected to the one second transistor of the second transistors being lower than or being equal to the potential of the common electrode.   
     
     
         12 . The electro-luminescent apparatus of  claim 11 ,
 wherein the second transistors are P-channel type.   
     
     
         13 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element of the luminescent elements being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the second transistor is in an “on” state:   a potential of the one power supply line of the power supply lines being higher than a potential of the opposite electrode, and a potential of the data signal to be supplied to the data line connected to the one second transistor of the second transistors being lower than or being equal to the potential of the opposite electrode.   
     
     
         14 . The electro-luminescent apparatus of  claim 13 ,
 wherein the second transistors are N-channel type.   
     
     
         15 . An electro-luminescent apparatus comprising:
 scanning lines;   data lines;   power supply lines;   pixel electrodes;   an opposite electrode formed to oppose the pixel electrodes;   luminescent elements, one luminescent element of the luminescent elements being interposed between one pixel electrode of the pixel electrodes and the opposite electrode;   first transistors, one first transistor of the first transistors having a gate electrode connected to one of the data lines; and   second transistors, one second transistor of the second transistors being connected between one pixel electrode of the pixel electrodes and one power supply line of the power supply lines,   when the one second transistor is in an “off” state:   a potential of the one power supply line of the power supply lines being higher than a potential of the opposite electrode, and a potential of the data signal to be supplied to the data line connected to the one second transistor of the second transistors being higher than or being equal to the potential of the common electrode.   
     
     
         16 . The electro-luminescent apparatus of  claim 15 ,
 wherein the second transistors are N-channel type.