Light emitting device and electronic equipment using the same
First Claim
1. A light emitting device with an OLED, comprising:
- means for measuring the current flowing between a first electrode and a second electrode of the OLED;
means for calculating, using a video signal, a reference value for the current flowing between the first electrode and the second electrode of the OLED; and
means for correcting the voltage between the first electrode and the second electrode of the OLED such that the measured current value approaches the reference current value.
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Accused Products
Abstract
A light emitting device is provided which is capable of displaying in desired colors stably by controlling a change in luminance of OLED when an organic light emitting layer is degraded or there is a change in temperature of the surroundings. A reference value for the amount of current flowing into a pixel portion is calculated from data of a video signal. Then, the pixel portion displays an image in accordance with the data of the video signal and the drive current at the time is measured for all of OLEDs in the pixel portion. The two voltage values supplied from a variable power supply to the pixel portion are corrected such that the measured drive current approaches the reference value. With the above structure, lowering of luminance which accompanies degradation of an organic light emitting layer is prevented and a clear image can be displayed as a result.
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Citations
85 Claims
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1. A light emitting device with an OLED, comprising:
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means for measuring the current flowing between a first electrode and a second electrode of the OLED;
means for calculating, using a video signal, a reference value for the current flowing between the first electrode and the second electrode of the OLED; and
means for correcting the voltage between the first electrode and the second electrode of the OLED such that the measured current value approaches the reference current value. - View Dependent Claims (2, 3, 4, 5)
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6. A light emitting device with an OLED, comprising:
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means for measuring the current flowing between a first electrode and a second electrode of the OLED;
means for calculating, using a video signal, a reference value for the current flowing between the first electrode and the second electrode of the OLED;
means for calculating the deviation of the measured current value from the reference current value;
means for calculating from the deviation such a voltage value between the first electrode and the second electrode of the OLED that makes the current flowing between the first electrode and the second electrode of the OLED approach the reference current value; and
means for correcting the voltage between the first electrode and the second electrode of the OLED so as to approach the calculated voltage value. - View Dependent Claims (7, 8, 9, 10, 11, 13, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25, 26, 27, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39, 40, 41, 42)
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12. A light emitting device with an OLED provided in each of plural pixels, comprising:
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means for measuring the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs;
means for calculating, using a video signal, a reference value for the total current between the first and second electrodes of all the OLEDs; and
means for correcting the voltage between the first electrode and the second electrode of every OLED such that the measured total current value approaches the reference total current value.
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17. A light emitting device with an OLED provided in each of plural pixels, comprising:
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means for measuring the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLED;
means for calculating, using a video signal, a reference value for the total current between the first and second electrodes of all the OLEDs;
means for calculating the deviation of the measured total current value from the reference total current value;
means for calculating from the deviation such a voltage value between the first electrode and the second electrode of every OLED that makes the total current between the first and second electrodes of all the OLEDs approach the reference total current value; and
means for correcting the voltage between the first electrode and the second electrode of every OLED so as to approach the calculated voltage value.
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23. A light emitting device with an OLED provided in each of plural pixels, comprising:
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means for measuring the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs;
means for calculating, using a video signal, the number of emitting OLEDs and for calculating a measured current value of each emitting OLED from the number of emitting OLEDs and from the measured total current value; and
means for correcting the voltage between the first electrode and the second electrode of every OLED such that the measured current value of each emitting OLED approaches a reference value for the current flowing between the first electrode and the second electrode of each emitting OLED.
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28. A light emitting device with an OLED provided in each of plural pixels, comprising:
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means for measuring the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs;
means for calculating, using a video signal, the number of emitting OLEDs and for calculating a measured current value of each emitting OLED from the number of emitting OLEDs and from the measured total current value;
means for calculating the deviation of the measured current value of each emitting OLED from a reference value for the current flowing between the first electrode and the second electrode of each emitting OLED;
means for calculating from the deviation such a voltage value between the first electrode and the second electrode of every OLED that makes the current between the first and second electrodes of each emitting OLED approach the reference current value; and
means for correcting the voltage between the first electrode and the second electrode of every OLED so as to approach the calculated voltage value.
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34. A light emitting device having a pixel portion, a correction circuit, a variable power supply, and an ammeter,
wherein the pixel portion is provided with a plurality of pixels each having an OLED, wherein the ammeter measures the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs, wherein the correction circuit has: -
at least one circuit for calculating, using a video signal, a reference value for the total current between the first and second electrodes of all the OLEDs; and
at least one circuit for correcting with the variable power supply the voltage between the first electrode and the second electrode of every OLED such that the measured total current value approaches the reference total current value.
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43. A light emitting device having a pixel portion, a correction circuit, a variable power supply, and an ammeter.
wherein the pixel portion is provided with a plurality of pixels each having an OLED, wherein the ammeter measures the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs, wherein the correction circuit has: -
at least one circuit for calculating, using a video signal, a reference value for the total current between the first and second electrodes of all the OLEDs;
at least one circuit for calculating the deviation of the measured total current value from the reference total current value;
at least one circuit for calculating from the deviation such a voltage value between the first electrode and the second electrode of every OLED that makes the total current between the first and second electrodes of all the OLEDs approach the reference total current value; and
at least one circuit for correcting with the variable power supply the voltage between the first electrode and the second electrode of every OLED so as to approach the calculated voltage value. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52)
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53. A light emitting device having a pixel portion, a correction circuit, a variable power supply, and an ammeter,
wherein the pixel portion is provided with a plurality of pixels each having an OLED, wherein the ammeter measures the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs, wherein the correction circuit has: -
at least a circuit for calculating, using a digital video signal, the number of emitting OLEDs and at least a circuit for calculating a measured current value of each emitting OLED from the number of emitting OLEDs and from the measured total current value; and
at least one circuit for correcting with the variable power supply the voltage between the first electrode and the second electrode of every OLED such that the measured current value of each emitting OLED approaches a reference value for the current flowing between the first electrode and the second electrode of each emitting OLED. - View Dependent Claims (54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. A light emitting device having a pixel portion, a correction circuit, a variable power supply, and an ammeter.
wherein the pixel portion is provided with a plurality of pixels each having an OLED, wherein the ammeter measures the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs. wherein the correction circuit has: -
at least one circuit for calculating, using a digital video signal, the number of emitting OLEDs and for calculating a measured current value of each emitting OLED from the number of emitting OLEDs and from the measured total current value;
at least one circuit for calculating the deviation of the measured current value of each emitting OLED from a reference value for the current flowing between the first electrode and the second electrode of each emitting OLED;
at least one circuit for calculating from the deviation such a voltage value between the first electrode and the second electrode of every OLED that makes the current between the first and second electrodes of each emitting OLED approach the reference current value; and
at least one circuit for correcting with the variable power supply the voltage between the first electrode and the second electrode of every OLED so as to approach the calculated voltage value. - View Dependent Claims (64, 65, 66, 67, 68, 69, 70, 71, 72, 73)
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74. A light emitting device having a pixel portion, a correction circuit, a variable power supply, and an ammeter, the correction circuit including a memory.
wherein the pixel portion is provided with a plurality of pixels each having an OLED, wherein the ammeter measures the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs, and wherein the correction circuit has: -
at least one circuit for calculating, using a digital video signal, the number of emitting OLEDs in each line to store the calculated number in the memory;
at least one circuit for calculating the total number of emitting OLEDs from the number of emitting OLEDs in each line which has been stored in the memory;
at least one circuit for calculating a measured current value of each emitting OLED from the total number of emitting OLEDs and from the measured total current value;
at least one circuit for correcting with the variable power supply the voltage between the first electrode and the second electrode of every OLED so that the measured current value of each emitting OLED approaches the reference current value flowing between the first electrode and the second electrode of each emitting OLED. - View Dependent Claims (75, 76, 77, 78, 79)
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80. A light emitting device having a pixel portion, a correction circuit, a variable power supply, and an ammeter, the correction circuit including a memory,
wherein the pixel portion is provided with a plurality of pixels each having an OLED, wherein the ammeter measures the current flowing between a first electrode and a second electrode of every OLED to obtain the total current between the first and second electrodes of all the OLEDs, and wherein the correction circuit has: -
at least one circuit for calculating, using a digital video signal, the number of emitting OLEDs in each line to store the calculated number in the memory;
at least one circuit for calculating the total number of emitting OLEDs from the number of emitting OLEDs in each line which has been stored in the memory;
at least one circuit for calculating a measured current value of each emitting OLED from the total number of emitting OLEDs and from the measured total current value;
at least one circuit for calculating the deviation of the measured current value of each emitting OLED from a reference value for the current flowing between the first electrode and the second electrode of each emitting OLED;
at least one circuit for calculating from the deviation such a voltage value between the first electrode and the second electrode of every OLED that makes the current between the first and second electrodes of each emitting OLED approach the reference current value; and
at least one circuit for correcting with the variable power supply the voltage between the first electrode and the second electrode of every OLED so as to approach the calculated voltage value. - View Dependent Claims (81, 82, 83, 84, 85)
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Specification