Image display device and electronic appliance

• US 20110163943A1
• Filed: 03/10/2011
• Published: 07/07/2011
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Tanikame, Takao, Yamashita, Junichi, Minami, Tetsuo, Mitomi, Yutaka
• Granted Patent: US 9,818,340 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: H01L 29/78678 with inverted-type structure, e.g. with bottom gate
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals

Abstract

An image display device includes: a pixel array part formed of first to fourth scanning lines arranged in rows, signal lines arranged in columns, pixel circuits in a matrix connected to the scanning lines and signal lines, and a plurality of power source lines which supplies first to third potentials necessary for the operations of pixel circuit; a signal part which supplies a video signal to the signal lines; and a scanner part which supplies a control signal to the first to fourth scanning lines, and in turn scans the pixel circuit for every row, wherein the pixel circuits include a sampling transistor, a drive transistor, first to third switching transistors, a pixel capacitance, and a light emitting device, and a channel length of the drive transistor is made longer than a channel length of the switching transistors to suppress fluctuations in threshold voltage.

Claims

1. An image display device comprising:

scanning lines arranged in rows;

signal lines arranged in columns; and

pixel circuits in a matrix connected to the scanning lines and the signal lines,

wherein each of the pixel circuits includes a sampling transistor, a switching transistor, a drive transistor, a pixel capacitance, and a light emitting device,

the sampling transistor samples a signal potential of supplied from each of the signal lines to the pixel capacitance,

the pixel capacitance connects between a source and the gate of the drive transistor, and

a channel length of the drive transistor is longer than a channel length of the switching transistor.

2. The image display device according to claim 1, wherein the channel length of the drive transistor is set to 10 μ

m or greater.

3. The image display device according to claim 1, wherein in each of the pixel circuits, the channel length of the drive transistor is set so that during the light emission period, the source potential of the drive transistor is varied, whereas the input voltage applied to the gate of the drive transistor is not varied with reference to the source potential.

4. The image display device according to claim 1, wherein an output of the drive transistor has dependence on a carrier mobility in a channel region.

5. The image display device according to claim 1, wherein the switching transistor is one of a plurality of switching transistors, and the channel length of the drive transistor is longer than the channel length of each of the plurality of switching transistors.

6. An electronic appliance having the image display device according to claim 1.