Display apparatus and fabrication method and fabrication apparatus for the same
View Patent ↗A pixel array section includes a plurality of pixel circuits disposed in a matrix and each including a driving transistor, a storage capacitor, an electro-optical element, and a sampling transistor. Each pixel circuit includes a pixel divided into a plurality of divisional pixels for each of which an electro-optical element is provided, and a test transistor provided between the driving transistor and the electro-optical elements for carrying out on/off operations for specifying whether or not the electro-optical element is a dark spot element so that the electro-optical element of the dark spot can be specified. The number of the test transistors is smaller than the number of the divisional elements of the original one pixel.
1. A display apparatus comprising:
a pixel circuit including
a storage capacitor configured to store information corresponding to an image signal,
a sampling transistor configured to write the information corresponding to an image signal into the storage capacitor,
a driving transistor configured to produce a driving current whose magnitude corresponds to a voltage stored in the storage capacitor,
M electro-optical elements connected to an output terminal of the driving transistor, where M is an integer greater than 1, and
N test transistors, where N is an integer less than M,
wherein each of the N test transistors is configured to selectively control current flowing between a corresponding one of the M electro-optical elements and a current path to the output terminal of the driving transistor, and
wherein at least one of the M electro-optical elements is not configured to have a corresponding test transistor that selectively controls current flowing between the at least one of the M electro-optical elements and a current path to the output terminal of the driving transistor.
2. The display apparatus of claim 1 , further comprising:
a control circuit configured to perform a dark spot detection process comprising causing ones of the N test transistors to be selectively turned off and on while driving current is produced by the driving transistor such that any of the M electro-optical elements that comprise dark spots can be detected.
3. The display apparatus of claim 2 ,
wherein the dark spot detection process further comprises the steps of, while driving current is produced by the driving transistor:
turning off all of the N test transistors,
successively turning on a different one of the N test transistors until all of the N test transistors have been turned on.
4. The display apparatus of claim 3 , wherein in the dark spot detection process, when performing the step of successively turning on a different one of the N test transistors until all of the N test transistors have been turned on, each transistor that has been turned on is thereafter maintained in an on-state until all of the N test transistors have been turned on.
5. The display apparatus of claim 2 , wherein the control circuit is further configured to perform an image display process comprising:
causing the sampling transistor to write information corresponding to an image signal that corresponds to luminance information of an image to be displayed into the storage capacitor;
causing the driving transistor to produce a driving current corresponding to the information; and
causing all of those of the N test transistors that correspond to an electro-optical element that has not been detected as a dark spot to be simultaneously maintained in an on-state throughout a light emission period.
6. The display apparatus of claim 5 , wherein the image display process further comprises causing all of those of the N test transistors that correspond to an electro-optical element that has been detected as a dark spot to be maintained in an off-state throughout the light emission period.
7. The display apparatus of claim 2 , wherein the control circuit is further configured to cause all of those of the N test transistors that correspond to an electro-optical element that has not been detected as a dark spot to always be in an on-state.
8. The display apparatus of claim 1 , wherein each of the electro-optical elements of the pixel circuit are configured to emit light of a same color.
9. The display apparatus of claim 1 ,
wherein M=2 and N=1, and
wherein the N=1 test transistor is disposed between the capacitor and the drive transistor such that the N=1 test transistor controls conduction between the capacitor and the drive transistor.
10. The display apparatus of claim 1 , further comprising a terminal section configured to serve as an interface for a test pulse supplied from an external dark spot inspection apparatus for controlling the N test transistors between on and off states.
11. The display apparatus of claim 1 , wherein, when N>1, the N test transistors are connected to each other in series with a first one of the N test transistors being connected the output terminal of the driving transistor.
12. A method of correcting dark spots of a pixel circuit, comprising:
causing ones of N test transistors that are connected to M electro-optical elements that are included in the pixel circuit to be selectively turned off and on while driving current is produced by a driving transistor included in the pixel circuit and connected to the M electro-optical elements;
detecting any of the M electro-optical elements that is a dark spot; and
electrically isolating any of the M electro-optical elements that are detected as a dark spot,
wherein M is an integer greater than 1 and N is an integer less than M,
wherein each of the N test transistors is configured to selectively control current flowing between a corresponding one of the M electro-optical elements and a current path to the output terminal of the driving transistor, and
wherein at least one of the M electro-optical elements does not have a corresponding test transistor that selectively controls current flowing between the at least one of the M electro-optical elements and a current path to the output terminal of the driving transistor.
13. The method of claim 12 , further comprising, while driving current is produced by the driving transistor, successively performing the steps of:
turning off all of the N test transistors;
detecting whether the at least one of the M electro-optical elements that does not correspond to a test transistor is a dark spot by detecting whether light is emitted thereby; and
when the at least one of the M electro-optical elements that does not correspond to a test transistor is not detected as a dark spot:
turning on a first one of the N test transistors, and
detecting whether the one of the M electro-optical elements that corresponds to the first one of N the test transistors is a dark spot by detecting whether light is emitted thereby.
14. The method of claim 13 , further comprising, when M>2,
after detecting whether the one of the M electro-optical elements that corresponds to the first one of N the test transistors is a dark spot, successively turning on a different one of the N test transistors until all of the N test transistors have been turned on, and
after turning on one of the N test transistors, detecting whether the electro-optical element corresponding thereto is a dark spot before turning on a next one of the N test transistors.
15. The method of claim 12 ,
wherein, when N>1, the N test transistors are connected to each other in series with a first one of the N test transistors being connected the output terminal of the driving transistor, and
wherein the method further comprises, while driving current is produced by the driving transistor, successively performing the steps of:
turning off the first one of the N test transistors;
detecting whether the at least one of the M electro-optical elements that does not correspond to a test transistor is a dark spot by detecting whether light is emitted thereby; and
when the at least one of the M electro-optical elements that does not correspond to a test transistor is not detected as a dark spot:
turning on the first one of the N test transistors while the one of the N test transistors connected thereto is in an off state, and
detecting whether the one of the M electro-optical elements that corresponds to the first one of N the test transistors is a dark spot by detecting whether light is emitted thereby.
16. The method of claim 15 , further comprising,
after detecting whether the one of the M electro-optical elements that corresponds to the first one of N the test transistors is a dark spot, successively turning on a different one of the N test transistors until all of the N test transistors have been turned on, where the N transistors are turned on in order with those of the N test transistors that are closer in the series connection to the output terminal of the driving transistor being turned on first; and
for each of the N test transistors, after turning on one of the N test transistors, detecting whether the electro-optical element corresponding thereto is a dark spot while at least a next one of the N test transistors is in an off state and before turning on the next one of the N test transistors.