Deformable micromirror device

• US 7,969,384 B2
• Filed: 12/26/2007
• Issued: 06/28/2011
• Est. Priority Date: 12/27/2006
• Status: Expired due to Fees

• Current Assignee: Ignite USA (Ignite), Olympus Corporation
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Maeda, Yoshihiro, Arai, Kazuma, Ishii, Fusao
• Primary Examiner(s): OSORIO, RICARDO
• Application Number:
  US12/005,544
• Publication Number:
  US 20090201236A1
• Time in Patent Office: 1,280 Days
• Field of Search: 345/32, 345/204, 345/55, 345 87- 89, 345 98-100, 345/690, 345/103, 345/84
• US Class Current: 345/32
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: H04N 9/3123 using pulse width modulation

Abstract

A micromirror device, which makes an image display with digital image data, comprises pixel elements each of which makes pulse width modulation (PWM) for incident light depending on the deflection state of light and which are arranged in the form of a matrix. Each of the pixel elements has a mirror, at least one memory cell comprising a transistor and a capacitor, and an electrode connected to each transistor. Memory cells arranged successively in a ROW direction are connected by a ROW line. The image data is loaded at a time interval during which the voltage of the electrode can hold the deflection state of a pixel element.

Claims

1. A micromirror device for making an image display with digital image data, comprising:

pixel elements, each of which makes pulse width modulation (PWM) for incident light depending on a deflection state of each of said pixel elements and which are arranged in a form of a matrix, wherein;

each of said pixel elements has a mirror, at least one memory cell comprising a transistor and a capacitor, and an electrode connected to each transistor;

memory cells arranged successively in a ROW direction are connected by a ROW line; and

a timing controller loads the image data into said pixel elements at a time interval during which a voltage of the electrode can hold the deflection state of a pixel element.

2. The micromirror device according to claim 1, wherein:

the time interval during which the deflection state can be held is a display duration, which corresponds to a most significant bit (MSB) in a display gray scale of the micromirror device, or longer.

3. The micromirror device according to claim 1, wherein:

each of said pixel elements has, as deflection states, an ON state for deflecting incident light to projection optics, and an OFF state for deflecting incident light to a direction different from the projection optics.

4. The micromirror device according to claim 1, comprising:

pixel elements of 1920×

1080 [pixels] or more.

5. The micromirror device according to claim 1, wherein:

a pitch of the mirror is equal to or larger than 4 μ

m, and equal to or smaller than 10 μ

m.

6. The micromirror device according to claim 1, wherein:

a wiring material of the ROW line is any of Al, Cu, Au, and Ag, or an alloy containing any of these substances.

7. The micromirror device according to claim 1, wherein:

an inter-layer dielectric film of the ROW line contains any of SiO₂, SiC, SiOC, and SiOF.

8. The micromirror device according to claim 1, wherein:

an inter-layer dielectric film of the ROW line is doped with fluorine (F) or carbon (C).

9. The micromirror device according to claim 1, wherein:

each of said pixel elements has, as deflection states, an ON state for deflecting incident light to projection optics, an OFF state for deflecting incident light to a direction different from the projection optics, and an oscillation state where the mirror oscillates between the ON and the OFF states.

10. The micromirror device according to claim 9, wherein:

a loading interval of the image data is longer than an oscillation period of the mirror.

11. A micromirror device for making an image display with digital image data, comprising:

pixel elements, each of which makes pulse width modulation (PWM) for incident light depending on a deflection state of each of said pixel elements and which are arranged in a form of a matrix, wherein;

the array of said pixel elements is composed of B subsets each including pixel elements of M_s (COLUMNs)×

N_s (ROWs) (M_s, N_s and B are natural numbers);

each of said pixel elements has a mirror, at least one memory cell comprising a transistor and a capacitor, and an electrode connected to each transistor;

memory cells arranged successively in a ROW direction in each of the subsets are connected by an independent ROW line; and

a timing controller loads the image data into said pixel elements at a time interval during which a voltage of the electrode can hold the deflection state of a pixel element.

12. The micromirror device according to claim 11, wherein:

the time interval during which the deflection state can be held is a display duration, which corresponds to a most significant bit (MSB) in a display gray scale of the micromirror device, or longer.

13. The micromirror device according to claim 11, wherein:

each of said pixel elements has, as deflection states, an ON state for deflecting incident light to projection optics, and an OFF state for deflecting incident light to a direction different from the projection optics.

14. The micromirror device according to claim 11, comprising:

pixel elements of 1920×

1080 [pixels] or more.

15. The micromirror device according to claim 11, wherein:

a pitch of the mirror is equal to or larger than 4 [um], and equal to or smaller than 10 [um].

16. The micromirror device according to claim 11, wherein:

a wiring material of the ROW line is any of Al, Cu, Au, and Ag, or an alloy containing any of these substances.

17. The micromirror device according to claim 11, wherein:

an inter-layer dielectric film of the ROW line contains any of SiO₂, SiC, SiOC, and SiOF.

18. The micromirror device according to claim 11, wherein:

an inter-layer dielectric film of the ROW line is doped with fluorine (F) or carbon (C).

19. The micromirror device according to claim 11, wherein:

each of said pixel elements has, as deflection states, an ON state for deflecting incident light to projection optics, an OFF state for deflecting incident light to a direction different from the projection optics, and an oscillation state where the mirror oscillates between the ON and the OFF states.

20. The micromirror device according to claim 19, wherein:

a loading interval of the image data is longer than an oscillation period of the mirror.

21. The micromirror device according to claim 11, further comprising:

at least one ROW line decoder for arbitrarily selecting and driving a ROW line, and

at least one COLUMN line driver for loading image data into each of the memory cells via a COLUMN line.

22. The micromirror device according to claim 11, wherein:

in the B subsets,

a first ROW line decoder and a first COLUMN line driver are connected to a first subset,

a second ROW line decoder and a second COLUMN line driver are connected to a second subset, and

the first and the second subsets are individually controlled so that the image data can be loaded at independent timings.

23. The micromirror device according to claim 11, comprising:

a data selector, wherein

said data selector distributes bit data of image data corresponding to each of the subsets in different order.