Display apparatus with narrow gap electrostatic actuators

• US 9,134,552 B2
• Filed: 03/13/2013
• Issued: 09/15/2015
• Est. Priority Date: 03/13/2013
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Ni Chleirigh, Cait, Andersson, Mark B., Dunn, Tyler, Wu, Joyce H.
• Primary Examiner(s): Lester, Evelyn A
• Application Number:
  US13/800,151
• Publication Number:
  US 20140268293A1
• Time in Patent Office: 916 Days
• Field of Search: 3592231-2242, 359/230, 359290-295, 359/298, 359/233.1, 345/85, 345/108
• US Class Current: 1/1
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 3/0056 Adjusting the distance between two elements, at least one of them being movable, e.g. air-gap tuning
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: G02B 26/00 Optical devices or arrangements for the control of light using movable or deformable optical elements control of light by modification of the optical properties of the media of the elements involved therein G02F1/00
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/007 the movable or deformable optical element controlling the colour, i.e. a spectral characteristic, of the light
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/023 comprising movable attenuating elements, e.g. neutral density filters
• 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: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/0068 having means for controlling the degree of correction, e.g. using phase modulators, movable elements controlling the phase of light using moving or deformable elements G02B26/06
• CPC Class Codes: G02F 1/0128 based on electro-mechanical, magneto-mechanical, elasto-optic effects
• CPC Class Codes: G09G 2300/0469 Details of the physics of pixel operation
• CPC Class Codes: G09G 2300/0473 Use of light emitting or modulating elements having two or more stable states when no power is applied
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• 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
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: H02N 1/006 of the gap-closing type H02N1/004 takes precedence

Abstract

This disclosure provides systems, methods and apparatus for incorporating tip-gap adjustment features (TGAF) in actuators of shutter assemblies. The TGAF are incorporated into a drive beam of the actuator during the formation of the shutter assembly over a mold. The TGAF are configured such that they develop a mechanical stress or stress gradient. When the shutter assembly is released from the mold, the stress or stress gradient in the TGAF bend the drive beam such that a tip-gap between the drive beam and a load beam of the actuator is reduced. The reduced tip-gap, in turn, reduces an actuation voltage needed to actuate the shutter assembly.

Claims

1. A display apparatus, comprising:

a substrate;

an electromechanical systems (EMS) electrostatic actuator mechanically coupled to the substrate and configured to move a light modulator in a direction parallel to a surface of the substrate, the actuator comprising;

a load beam electrode having a first end mechanically coupled to the light modulator and a second end mechanically coupled to a load beam anchor, the load beam anchor mechanically coupled to the substrate; and

a drive beam electrode having;

a first portion positioned adjacent to the load beam, a first end of the first portion mechanically coupled to a drive beam anchor, the drive beam anchor mechanically coupled to the substrate;

a second portion positioned behind the first portion with respect to the load beam, a first end of the second portion mechanically coupled to the drive beam anchor; and

an end portion connecting a second end of the first portion to a second end of the second portion, wherein the second portion has a plurality of U-shaped segments defining a plurality of channels, wherein beam regions within the plurality of channels have a thickness, measured in a direction parallel to the surface of the substrate, that is less than the thickness of outer beam regions formed outside of the channels, and wherein the channels have a width between 3 and 6 microns.

2. The apparatus of claim 1, wherein the first portion of the drive beam electrode includes a second generally U-shaped segment, having relatively smaller dimensions than a first U-shaped segment of the plurality of U-shaped segments.

3. The apparatus of claim 1, wherein the first portion, the end portion, and the second portion of the drive beam form a loop.

4. The apparatus of claim 1, further comprising:

a display;

a processor that is configured to communicate with the display, the processor being configured to process image data; and

a memory device that is configured to communicate with the processor.

5. The apparatus of claim 4, further comprising:

a driver circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit.

6. The apparatus of claim 4, further comprising:

an image source module configured to send the image data to the processor, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

7. The apparatus of claim 4, further comprising:

an input device configured to receive input data and to communicate the input data to the processor.

8. A display element, comprising:

a substrate;

an electromechanical systems (EMS) electrostatic actuator coupled to the substrate comprising;

a load beam electrode coupled to a light modulator; and

a drive beam electrode coupled to the substrate having;

a first portion positioned adjacent to the load beam electrode,

a second portion positioned behind the first portion with respect to the load beam electrode,

an end portion connecting the first portion to the second portion, and

a shelf structure separate from an anchor supporting the drive beam over the substrate, the shelf structure positioned along and mechanically coupled to the second portion of the drive beam and having a first planar surface that is substantially parallel to the substrate.

9. The display element of claim 8, wherein the first planar surface is positioned on a side of the second portion of the drive beam that is substantially normal to the substrate.

10. The display element of claim 8, wherein the first planar surface in positioned on an edge of the second portion of the drive beam that faces away from the substrate.

11. The display element of claim 8, wherein the shelf structure includes a second planar surface that is substantially parallel to the substrate and coupled to the second portion of the drive beam, the second planar surface positioned along and mechanically coupled to the second portion of the drive beam.

12. The display element of claim 11, wherein the first planar surface and the second planar surface are positioned on opposite ends of a side of the second portion that is substantially normal in relation to the substrate.

13. The display element of claim 8, wherein the shelf structure is physically separated from the first portion of the drive beam.

14. The display element of claim 8, wherein the first portion, the end portion, and the second portion of the drive beam form a loop.