Electro-optical device

• US 6,475,845 B2
• Filed: 03/26/2001
• Issued: 11/05/2002
• Est. Priority Date: 03/27/2000
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Dang, Phuc T.
• Application Number:
  US09/818,191
• Publication Number:
  US 20010026257A1
• Time in Patent Office: 589 Days
• Field of Search: 438/22, 438/99, 438/157, 438/158, 438/200, 438/201, 438/217
• US Class Current: 438/200
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• 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 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/325 the data current flowing through the driving transistor during a setting phase, e.g. by using a switch for connecting the driving transistor to the data driver
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/311 : Phthalocyanine
• CPC Class Codes: H10K 85/341 : Transition metal complexes, e.g. Ru(II)polypyridine complexes H10K85/331 takes precedence
• CPC Class Codes: H10K 85/60 : Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence

Abstract

An object of the present invention is to realize a numerical aperture higher than that of a pixel having a conventional construction by using a pixel circuit having a novel construction in an electro-optical device. Therefore, it is utilized that the electric potential of a gate signal line in a row except for an i-th row is set to a constant electric potential in a period except for when a gate signal line (106) in the i-th row is selected. A gate signal line 111 in an (i−1)-th row is also used as an electric current supply line for an EL element (103) controlled by the gate signal line (106) in the i-th row. Thus, wiring number is reduced and high numerical aperture is realized.

Claims

1. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and a pixel portion, comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein said switching transistor has a gate electrode electrically connected to a corresponding gate signal line and impurity regions, one of said impurity regions electrically connected to a corresponding source signal line and another one of said impurity regions electrically connected to a gate electrode of said EL driving transistor, and

wherein said EL driving transistor has impurity regions, one of said impurity regions electrically connected to one of said plurality of gate signal lines and another one of said impurity regions electrically connected to an electrode of said EL element.

9. A semiconductor device according to claim 1, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

17. A semiconductor device according claims 1, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

25. A semiconductor device according to claim 1, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.

2. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and a pixel portion comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein said switching transistor has a gate electrode electrically connected to an i-th gate signal line and impurity regions, one of said impurity regions electrically connected to a corresponding source signal line and another one of said impurity regions electrically connected to a gate electrode of said EL driving transistor, and

wherein said EL driving transistor has impurity regions, one of said impurity regions electrically connected to one of said plurality of gate signal lines and another one of said impurity regions electrically connected to an electrode of said EL element, and

wherein an electric current applied to said EL element corresponding to said i-th gate signal line is supplied through one of said plurality of gate signal lines electrically connected to one of impurity regions of said EL driving transistor.

10. A semiconductor device according to claim 2, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

18. A semiconductor device according claims 2, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

26. A semiconductor device according to claim 2, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.

3. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and a pixel portion comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein said switching transistor has a gate electrode electrically connected to ani-th gate signal line and impurity regions, one of said impurity regions electrically connected to a corresponding source signal line and another one of said impurity regions electrically connected to a gate electrode of said EL driving transistor, and

wherein said EL driving transistor has impurity regions, one of said impurity regions electrically connected to one of said plurality of gate signal lines and another one of said impurity regions electrically connected to an electrode of said EL element, and

wherein said i-th gate signal line has a function for controlling operations of pixels, each of said pixels having a switching element electrically connected to said i-th gate signal line and a function as an electric current supply line for pixels, each of said pixels having an EL driving transistor electrically connected to said i-th gate signal line.

11. A semiconductor device according to claim 3, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

19. A semiconductor device according claims 3, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

27. A semiconductor device according to claim 3, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.

4. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and a pixel portion, comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein said switching transistor has a gate electrode electrically connected to an i-th gate signal line and impurity regions, one of said impurity regions electrically connected to a corresponding source signal line and another one of said impurity regions electrically connected to a gate electrode of said EL driving transistor, and

wherein said EL driving transistor has impurity regions, one of said impurity regions electrically connected to one of said plurality of gate signal lines except for said i-th gate signal line and another one of said impurity regions electrically connected to an electrode of said EL element.

12. A semiconductor device according to claim 4, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

20. A semiconductor device according claims 4, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

28. A semiconductor device according to claim 4, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.

5. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and a pixel portion, comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein said switching transistor has a gate electrode electrically connected to an i-th gate signal line and impurity regions, one of said impurity regions electrically connected to a corresponding source signal line and another one of said impurity regions electrically connected to a gate electrode of said EL driving transistor, and

wherein said EL driving transistor has impurity regions, one of said impurity regions electrically connected to an (i−

1)-th gate signal line and another one of said impurity regions electrically connected to an electrode of said EL element.

13. A semiconductor device according to claim 5, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

21. A semiconductor device according claims 5, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

29. A semiconductor device according to claim 5, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.

6. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and a pixel portion, comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein a signal is inputted from a source signal line to said EL driving transistor through said switching transistor, and

wherein an electric current is supplied from one of said plurality of said gate signal lines to said EL element through said EL driving transistor.

14. A semiconductor device according to claim 6, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

22. A semiconductor device according claims 6, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

30. A semiconductor device according to claim 6, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.

7. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and pixel portion, comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein a signal is inputted from a corresponding source signal line to said EL driving transistor through said switching transistor having a gate electrode electrically connected to an i-th gate signal line, and

wherein an electric current is supplied from one of said plurality of gate signal lines except for said i-th gate signal line to said EL element through said EL driving transistor.

15. A semiconductor device according to claim 7, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

23. A semiconductor device according claims 7, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

31. A semiconductor device according to claim 7, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.

8. A semiconductor device having a source signal line side driving circuit, a gate signal line side driving circuit and a pixel portion, comprising:

a plurality of source signal lines connected to said source signal line side driving circuit;

a plurality of gate signal lines connected to said gate signal line side driving circuit;

a plurality of pixels arranged in a matrix-form in said pixel portion, each of pixels having at least a switching transistor, an EL driving transistor and an EL element;

wherein a signal is inputted from a source signal line to said EL driving transistor through said switching transistor having a gate electrode electrically connected an i-th gate signal line, and

wherein an electric current is supplied from an (i−

1)-th gate signal line to said EL element through said EL driving transistor.

16. A semiconductor device according to claim 8, wherein polarity of said EL driving transistor electrically connected to said EL element is p-channel type when a light emitting direction of the EL element is a direction directed to a substrate on which a driving circuit is formed,

the polarity of said EL driving transistor electrically connected to said EL element is n-channel type when the light emitting direction of said EL element is a direction reverse to the direction directed to the substrate on which the driving circuit is formed, and

polarity of said switching transistor is the same as the polarity of said EL driving transistor.

24. A semiconductor device according claims 8, wherein the gate signal line is formed by using aluminum or a material having aluminum as a principal component.

32. A semiconductor device according to claim 8, wherein said semiconductor device is a device selected from the group consisting of:

an EL display, a video camera, a head mount display, a DVD player, a personal computer, a portable phone and a car audio.