Display device and electronic device

• US 8,952,875 B2
• Filed: 04/17/2014
• Issued: 02/10/2015
• Est. Priority Date: 12/25/2009
• Status: Expired due to Fees

• Current Assignee: JOLED Inc.
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hasegawa, Hiroshi
• Primary Examiner(s): Pervan, Michael
• Application Number:
  US14/255,656
• Publication Number:
  US 20140225939A1
• Time in Patent Office: 299 Days
• Field of Search: 345 30-111, 345204-215, 345690-699
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3283 in which the data driver supplies a variable data current for setting the current through, or the voltage across, the light-emitting elements

Abstract

A display device in which an emission period may be adjusted into multiple types with reduction in cost being achieved. The display device includes: a plurality of pixels, each pixel including a plurality of individual-color sub-pixels, each sub-pixel including an individual-color light emitting element and an emission control transistor; and emission control lines connected to the pixels. The individual-color sub-pixel includes one of a first individual-color sub-pixel including an emission control transistor of a first conductive type, and a second individual-color sub-pixel including an emission control transistor of a second conductive type different from the first conductive type. One emission control line is connected in common with at least one of each of the first and second individual-color sub-pixels.

Claims

1. A display device comprising:

a plurality of pixels, each pixel having a plurality of individual-color sub-pixels, each sub-pixel including an individual-color light emitting element and having an emission period corresponding to luminous efficiency of the individual-color light emitting element; and

a plurality of emission control lines connected to the pixels,

wherein,

in each pixel, one emission control line among the plurality of emission control lines is connected in common to at least two of the plurality of individual-color sub-pixels, and

an emission-control-line drive circuit controls control pulses of the plurality of the emission control lines such that each of the control pulses has a period comprising a plurality of sub-periods, in which both a first emission control transistor and a second emission control transistor are set to be on during respective first and second sub-periods of the plurality of sub-periods and are set to be off concurrently during a third sub-period of the plurality of sub-periods, wherein at least two different individual-color light emitting elements are set to be on concurrently during the first sub-period.

2. The display device according to claim 1 wherein, the emission-control-line drive circuit is configured to apply control pulses to the emission control lines for each sub-pixel to control an on/off state of the emission control transistor of the respective individual-color light emitting element.

3. The display device according to claim 1, wherein the first emission control transistor is an n-type transistor, and the second emission control transistor is a p-type transistor.

4. The display device according to claim 3, wherein, in the first individual-color sub-pixel, the first emission control transistor is set to be (a) on for an emission operation during an H (high) period of each of the control pulses, and (b) off for an non-emission operation during an L (low) period of each of the control pulses, and

in the second individual-color sub-pixel, the second emission control transistor is set to be (a) on for an emission operation during the L (low) period of each of the control pulses, and (b) off for an non-emission operation during the H (high) period of each of the control pulses.

5. The display device according to claim 4 wherein the emission-control-line drive circuit is configured to apply control pulses to the emission control lines for controlling an on/off state of the emission control transistor of the respective individual-color light emitting element, and

the emission-control-line drive circuit is configured to control (a) length of an emission period of the first individual-color sub-pixel and length of a non-emission period of the second individual-color sub-pixel in accordance with length of the H period of each of the control pulses, and (b) length of a non-emission period of the first individual-color sub-pixel and length of an emission period of the second individual-color sub-pixel in accordance with length of the L period of each of the control pulses.

6. The display device according to claim 5, wherein the emission-control-line drive circuit is configured to control the control pulses such that each of the control pulses has a plurality of H periods and a plurality of L periods within one vertical period.

7. The display device according to claim 5, wherein the emission-control-line drive circuit is configured to adjust the length of the H period and the length of the L period of each of the control pulses such that an individual-color sub-pixel having a first individual-color light emitting element having a relatively high luminous efficiency is short in emission period compared with an individual-color sub-pixel having a second individual-color light emitting element having a relatively low luminous efficiency with respect to the first individual-color light emitting element.

8. The display device according to claim 1, wherein in each pixel, the one emission control line is connected in common to all individual-color sub-pixels.

9. The display device according to claim 8, wherein individual-color sub-pixels having individual-color light emitting elements having relatively similar values of luminous efficiency are set together as the first or second individual-color sub-pixel.

10. The display device according to claim 8, wherein individual-color sub-pixels having relatively similar values of luminosity factors specific to respective colors are set together as the first or second individual-color sub-pixel.

11. The display device according to claim 1, wherein one or more emission control lines are connected in common to, a first individual-color sub-pixel on a first horizontal line, on which only the first individual-color sub-pixel is selectively provided in each pixel, and a second individual-color sub-pixel on a second horizontal line, on which only the second individual-color sub-pixel is selectively provided in each pixel.

12. The display device according to claim 1, wherein each pixel is configured of three individual-color sub-pixels corresponding to three colors of red (R), green (G) and blue (B).

13. The display device according to claim 1, wherein each pixel is configured of four individual-color sub-pixels corresponding to four colors of red (R), green (G), blue (B) and white (W).

14. A light emitting apparatus comprising:

a plurality of light emitting devices, each of the light emitting device having a plurality of individual-color emitting devices, each of the individual-color emitting devices including an individual-color light emitting element and having an emission period corresponding to luminous efficiency of the individual-color light emitting element; and

a plurality of emission control lines connected to the light emitting devices,

wherein,

in each light emitting device, one emission control line among the plurality of emission control lines is connected in common to at least two of the plurality of individual-color emitting devices, and

an emission-control-line drive circuit configured to control control pulses of the plurality of the emission control lines such that each of the control pulses has a period comprising a plurality of sub-periods, in which both a first emission control transistor and a second emission control transistor are set to be on during respective first and second sub-periods of the plurality of sub-periods and are set to be off concurrently during a third sub-period of the plurality of sub-periods,

wherein,

at least two different individual-color light emitting elements are set to be on concurrently during the first sub-period.

15. The display device according to claim 14 wherein the emission-control-line drive circuit is configured to apply control pulses to the plurality of emission control lines for controlling emission operation and non-emission operation of the individual-color light emitting element, and

a length of an emission period and a length of a non-emission period of each of the plurality of individual-color sub-pixels are controlled in correspondence to width of each of the control pulses.

16. The display device according to claim 15, wherein the emission-control-line drive circuit is configured to adjust a width of each control pulse applied to the emission control lines such that an emission period of a first individual-color sub-pixel, being set to be relatively long in emission period, is provided during and before or after the whole emission period of a second individual-color sub-pixel being set to be relatively short in emission period with respect to the first individual-color sub-pixel.

17. The display device according to claim 16, wherein the emission period of the second individual-color sub-pixel is divided into multiple periods separated from one another.

18. The display device according to claim 14 further comprising, in each pixel:

a scan line connected in common to the plurality of individual-color sub-pixels,

a plurality of signal lines for individual colors individually connected to the plurality of individual-color sub-pixels,

a scan line drive circuit configured to apply selection pulses to the scan line for sequentially selecting the plurality of pixels, and

a signal line drive circuit configured to individually apply video signal voltages for individual colors to the plurality of signal lines for individual colors to write a video signal to each of the plurality of individual-color sub-pixels in a pixel selected by the scan line drive circuit.