Light-emitting device

Patent metadata

Field	Value
Publication number	US-9502483-B2
Application number	US-201615132332-A
Country	US
Kind code	B2
Filing date	Apr 19, 2016
Priority date	Feb 29, 2000
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

There is provided an EL light-emitting device with less uneven brightness. When a drain current of a plurality of current controlling TFTs is Id, a mobility is μ, a gate capacitance per unit area is Co, a maximum gate voltage is Vgs (max) , a channel width is W, a channel length is L, an average value of a threshold voltage is Vth, a deviation from the average value of the threshold voltage is ΔVth, and a difference in emission brightness of a plurality of EL elements is within a range of ±n %, a semiconductor display device is characterized in that

A
=

2
⁢

⁢
Id

μ
*

C
0

A

(

Vgs

(
max
)

-
Vth

)

2

≦

W
L

≦

(

1
+

n
100

-
1

)

2

*

A

Δ
⁢

⁢

Vth
2



Δ
⁢

⁢
Vth



≦

(

1
+

n
100

-
1

)

*

A
*

L
/
W

.

First claim

What is claimed is:

1. A semiconductor device comprising:
a first transistor of a first pixel comprising a first channel forming region, the first channel forming region having a first channel width and a first channel length;
a second transistor of a second pixel comprising a second channel forming region, the second channel forming region having a second channel width and a second channel length;
a first signal line configured to supply a signal to the first transistor;
a second signal line configured to supply a signal to the second transistor;
a current supply line between the first signal line and the second signal line, the current supply line being electrically connected to the first transistor and the second transistor;
a first pixel electrode of the first pixel, the first pixel electrode being electrically connected to the first transistor;
a second pixel electrode of the second pixel, the second pixel electrode being electrically connected to the second transistor;
a first layer including an organic light emitting material, the first layer being over the first pixel electrode; and
a second layer including an organic light emitting material, the second layer being over the second pixel electrode,
wherein a ratio of the first channel width to the first channel length of the first transistor is lower than or equal to 0.214, and
wherein a ratio of the second channel width to the second channel length of the first transistor is lower than or equal to 0.214.

2. The semiconductor device according to claim 1 , wherein the first layer is configured to emit light of a first color, the second layer is configured to emit light of a second color, and the first color is different from the second color.

3. The semiconductor device according to claim 1 , wherein each of the first transistor and the second transistor is a thin film transistor.

4. The semiconductor device according to claim 1 , wherein each of the first transistor and the second transistor is a current controlling thin film transistor.

5. The semiconductor device according to claim 1 , wherein each of the first transistor and the second transistor is a top-gate transistor.

6. The semiconductor device according to claim 1 , wherein each of the first transistor and the second transistor includes a poly-crystalline semiconductor film.

7. The semiconductor device according to claim 1 ,
wherein the first pixel further comprises a first switching transistor, and
wherein the second pixel further comprises a second switching transistor.

8. An electronic apparatus having the semiconductor device according to claim 1 , wherein the electronic apparatus is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a car navigation system, an audio reproduction device, a notebook personal computer, a game equipment, a mobile computer, a mobile telephone, a mobile game equipment, an electronic book, and an image reproduction device provided with a recording medium.

9. An electronic apparatus having the semiconductor device according to claim 1 , wherein the electronic apparatus is one selected from the group consisting of a video camera, a digital camera, a goggle type display, a car navigation system, an audio reproduction device, a notebook personal computer, a game equipment, a mobile computer, a mobile telephone, a mobile game equipment, an electronic book, and an image reproduction device provided with a recording medium.

10. A semiconductor device comprising:
a first transistor of a first pixel comprising a first channel forming region, the first channel forming region having a first channel width and a first channel length;
a second transistor of a second pixel comprising a second channel forming region, the second channel forming region having a second channel width and a second channel length;
a first signal line configured to supply a signal to the first transistor;
a second signal line configured to supply a signal to the second transistor;
a current supply line between the first signal line and the second signal line, the current supply line being electrically connected to the first transistor and the second transistor;
a first pixel electrode of the first pixel, the first pixel electrode being electrically connected to the first transistor;
a second pixel electrode of the second pixel, the second pixel electrode being electrically connected to the second transistor;
a first layer including an organic light emitting material, the first layer being over the first pixel electrode;
a second layer including an organic light emitting material, the second layer being over the second pixel electrode,
a first capacitor electrically connected to the first transistor and the current supply line; and
a second capacitor electrically connected to the second transistor and the current supply line,
wherein a ratio of the first channel width to the first channel length of the first transistor is lower than or equal to 0.214, and
wherein a ratio of the second channel width to the second channel length of the first transistor is lower than or equal to 0.214.

11. The semiconductor device according to claim 10 , wherein the first layer is configured to emit light of a first color, the second layer is configured to emit light of a second color, and the first color is different from the second color.

12. The semiconductor device according to claim 10 , wherein each of the first transistor and the second transistor is a thin film transistor.

13. The semiconductor device according to claim 10 , wherein each of the first transistor and the second transistor is a current controlling thin film transistor.

14. The semiconductor device according to claim 10 , wherein each of the first transistor and the second transistor is a top-gate transistor.

15. The semiconductor device according to claim 10 , wherein each of the first transistor and the second transistor includes a poly-crystalline semiconductor film.

16. The semiconductor device according to claim 10 ,
wherein the first pixel further comprises a first switching transistor, and
wherein the second pixel further comprises a second switching transistor.

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei
• Koyama Jun
• Osada Mai

Classifications

• H10D30/6757

  characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715) · CPC title

• H10K59/8722

  Peripheral sealing arrangements, e.g. adhesives, sealants · CPC title

• H10K59/871

  Self-supporting sealing arrangements · CPC title

• H10K59/1213

  the pixel elements being TFTs · CPC title

• G09G3/3233 Primary

  with pixel circuitry controlling the current through the light-emitting element · CPC title