MEMS device having distance stops

• US 20080001913A1
• Filed: 06/30/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Nikkel, Eric L., Cruz-Uribe, Tony S., Jilani, Adel, Faase, Kenneth J., Yeh, Bao
• Granted Patent: US 7,741,751 B2
• Time in Patent Office: Days
• US Class Current: 345/108
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular to the substrate
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38

Abstract

A micro-electromechanical systems (MEMS) device includes bottom and top capacitive plates, such that a capacitor is definable therebetween. A mechanism is electrostatically movably disposed between the bottom and top capacitive plates. One or more flexures are movably disposed between the bottom capacitive plate and the mechanism, and having distance stops between the bottom capacitive plate and the mechanism corresponding to maximum downward movement. The MEMS device includes one or more electrodes of the bottom capacitive plate corresponding to the flexures. Energizing different of the electrodes causes the flexures to move to different of the distance stops, causing the mechanism to move to different positions between the bottom and top capacitive plates.

Claims

1. A micro-electromechanical systems (MEMS) device comprising:

a bottom capacitive plate;

a top capacitive plate, such that a capacitor is definable between the bottom and the top capacitive plates;

a mechanism electrostatically movably disposed between the bottom and the top capacitive plates;

one or more flexures movably disposed between the bottom capacitive plate and the mechanism and having distance stops between the bottom capacitive plate and the mechanism corresponding to maximum downward movement; and

,

one or more electrodes of the bottom capacitive plate and corresponding to the flexures, such that energizing different of the electrodes causes the flexures to move to different of the distance stops, resultantly causing the mechanism to move to different positions between the bottom and the top capacitive plates.

2. The MEMS device of claim 1, wherein at least one of the flexures move to a first distance stop where the top capacitive plate and all the electrodes are at a first voltage level, such that the mechanism moves to a first position between the bottom and the top capacitive plates, corresponding to a first state of the MEMS device.

3. The MEMS device of claim 2, wherein at least one of the flexures move to a second distance stop where the top capacitive plate and a first subset of the electrodes are at the first voltage level and a second subset of the electrodes are at a second voltage level, such that the mechanism moves to a second position between the bottom and the top capacitive plates closer to the bottom capacitive plate than the first position and corresponding to a second state of the MEMS device.

4. The MEMS device of claim 3, wherein at least one of the flexures move to a third distance stop where the top capacitive plate and the first subset of the electrodes are at the first voltage level, the second subset of the electrodes are at the second voltage level, and a third subset of the electrodes are a third voltage level, such that the mechanism moves to a third position between the bottom and the top capacitive plates closer to the bottom capacitive plate than the second position and corresponding to a third state of the MEMS device.

5. The MEMS device of claim 4, wherein where the top capacitive plate is at a fourth voltage level and all the electrodes are at the first voltage level, the mechanism moves to a fourth position between the bottom and the top capacitive plates closer to the top capacitive plate than the first position and corresponding to a fourth state of the MEMS device.

6. The MEMS device of claim 1, wherein the one or more flexures comprise a plurality of flexures.

7. The MEMS device of claim 6, wherein the mechanism comprises a plurality of sub-plates having physical stops corresponding to the distance stops of the flexures.

8. The MEMS device of claim 7, wherein the sub-plates are concentric to one another.

9. The MEMS device of claim 1, wherein the one or more flexures comprise a plurality of flexures, the MEMS device further comprising a plurality of physical stops corresponding to the flexures and to the distance stops.

10. The MEMS device of claim 9, wherein the MEMS device further comprises a rigid frame attached to a first subset of the flexures and corresponding to a first subset of the physical stops and to a first subset of the distance stops, the mechanism attached to a second subset of the flexures and corresponding to a second subset of the physical stops and to a second subset of the distance stops.

11. The MEMS device of claim 10, wherein the flexures are organized in rows between a first end and a second end of the rigid frame.

12. The MEMS device of claim 11, wherein the rigid frame comprises one or more cross beams between the first and the second ends of the rigid frame.

13. The MEMS device of claim 11, wherein the flexures are wider at the first and the second ends of the rigid frame and are tapered such that the flexures are narrower at a middle between the first and the second ends of the rigid frame.

14. The MEMS device of claim 11, wherein the flexures are wider at the first and the second ends of the rigid frame and at a middle between the first and the second ends of the rigid frame, and are tapered such that the flexures are narrower between the middle and the first end of the rigid frame and between the middle and the second end of the rigid frame.

15. The MEMS device of claim 1, wherein radiation entering the MEMS device at the top capacitive plate is reflected back upwards by the mechanism differently based on a position of the mechanism between the bottom and the top capacitive plates.

16. The MEMS device of claim 1, wherein the MEMS device is a display element, and the mechanism is an optical mechanism comprising a reflective plate, such that the radiation entering the MEMS device is visible white light and is reflected back as visible light of a single color.

17. A display device comprising:

a plurality of display elements corresponding to a plurality of pixels of the display device, each display element having a reflective plate electrostatically movable to different positions based on a number of distance stops,

wherein visible light enters each display element and is reflected back by the reflective plate differently based on a position of the reflective plate.

18. The display device of claim 17, wherein each display element comprises:

a plurality of flexures having the distance stops;

a plurality of physical stops corresponding to the flexures and to the distance stops; and

,

a rigid frame attached to a first subset of the flexures and corresponding to a first subset of the physical stops and to a first subset of the distance stops, the reflective plate attached to a second subset of the flexures and corresponding to a second subset of the physical stops and to a second subset of the distance stops.

19. A method comprising:

for each display element of a plurality of display elements of a display device,

determining a color to be displayed by the display element as one of a discrete number of colors;

determining a position of an electrostatically movable reflective plate of the display element corresponding to the color to be displayed by the display element; and

,

energizing a plurality of electrodes of the display element to move the reflective plate to the position corresponding to the color to be displayed by the display element,

wherein energizing the electrodes causes at least one of a plurality of flexures of the display element to move to one of a plurality of distance stops, resultantly causing the reflective plate to move to the position corresponding to the color to be displayed by the display element.

20. The method of claim 19, wherein, for each display element,

at least one of the flexures move to a first distance stop where a top capacitive plate of the display element and all the electrodes are at a first voltage level, such that the reflective plate moves to a first position corresponding to a first color of the display element,

at least one of the flexures move to a second distance stop where the top capacitive plate and a first subset of the electrodes are at the first voltage level and a second subset of the electrodes are at a second voltage level, such that the reflective plate moves to a second position corresponding to a second color of the display element, and/or

at least one of the flexures move to a third distance stop where the top capacitive plate and the first subset of the electrodes are at the first voltage level, the second subset of the electrodes are at the second voltage level, and a third subset of the electrodes are a third voltage level, such that the reflective plate moves to a third position corresponding to a third color of the display element.