Interferometric modulation of radiation

• US 7,042,643 B2
• Filed: 02/19/2002
• Issued: 05/09/2006
• Est. Priority Date: 05/05/1994
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark W.
• Primary Examiner(s): Lester, Evelyn A.
• Application Number:
  US10/078,282
• Publication Number:
  US 20020126364A1
• Time in Patent Office: 1,540 Days
• Field of Search: 359/1, 359/11, 359/290, 359/291, 359/279, 359/318, 359/317, 359577-579
• US Class Current: 359/578
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• CPC Class Codes: G02B 2027/0112 comprising device for genereting colour display
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• 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 26/02 for controlling the intensity of light G02B26/004 takes precedence
• 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 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 6/12 of the integrated circuit kind electric integrated circuits H01L27/00
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: G02F 1/216 using liquid crystals, e.g. liquid crystal Fabry-Perot filters
• CPC Class Codes: G02F 2203/03 scattering
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/3466 : based on interferometric effect

Abstract

An Interferometric Modulator (IMod) is a microelectromechanical device for modulating light using interference. The colors of these devices may be determined in a spatial fashion, and their inherent color shift may be compensated for using several optical compensation mechanisms. Brightness, addressing, and driving of IMods may be accomplished in a variety of ways with appropriate packaging, and peripheral electronics which can be attached and/or fabricated using one of many techniques. The devices may be used in both embedded and directly perceived applications, the latter providing multiple viewing modes as well as a multitude of product concepts ranging in size from microscopic to architectural in scope.

• • In another aspect, a structure for modulating light comprises modulators of light each including an interference cavity for causing interference modulation of the light. The structure further comprises an optical compensation mechanism component coupled to the modulators which enhances the optical performance of the structure, the component comprising one or more of a photonic crystal array, a mutlilayer array of dielectric mirrors, and an array of microlenses.
  • In another aspect, a device for modulating light comprises an array of interference modulators, each comprising a primary and a secondary mirror which in a quiescent state is spaced from the primary mirror by a first distance so that light reflected from the modulator is of a first color, and which in a second state, under influence of a bias voltage, is spaced from the primary mirror by a second distance which is less than the first distance so that the modulator reflects light of a second color. The device further comprises an optical compensation mechanism component coupled to the array to compensate for changes in a color of light reflected by the array due to changes in a angle at which the array is viewed.
  • In another aspect, a method for fabricating a reflective display comprises fabricating an array of interference modulators, each comprising a primary and a secondary mirror which in a quiescent state is spaced on the primary mirror by a first distance so that light reflected from the modulator is of a first color, and which in a second state, under influence of a biased voltage is spaced from the primary mirror by a second distance which is less than the first distance so that the modulator reflects light of a second color. The method further comprises coupling an optical compensation mechanism component to the array of interference modulators to compensate for changes in a color of light reflected by the array due to changes in an angle at which the array is viewed.

Claims

1. A structure for modulating light comprising:

modulators of light each including an interference cavity for causing interference modulation of the light, and

an optical compensation component coupled to the modulators which enhances the optical performance of the structure, the component comprising one or more of a photonic crystal array, a multilayer array of dielectric mirrors, and an array of microlenses.

2. The structure of claim 1 in which the component comprises a photonic crystal array.

3. The structure of claim 1 which the component comprises a multilayer array of dielectric mirrors.

4. The structure of claim 1 in which the component comprises an array of microlenses.

5. The structure of claim 1 in which the component coupled to the modulators enhances the optical performance of the structure by minimizing color shift.

6. The structure of claim 1 in which the component coupled to the modulators enhances the optical performance of the structure by supplying supplemental illumination.

7. A device for modulating light, comprising:

an array of interference modulators, each comprising a primary and a secondary mirror which in a quiescent state is spaced from the primary mirror by a first distance so that light reflected from the modulator is of a first color, and which in a second state, under influence of a bias voltage, is spaced from the primary mirror by a second distance which is less than the first distance so that the modulator reflects light of a second color, and

an optical compensation component coupled to the array to compensate for changes in a color of light reflected by the array due to changes in an angle at which the array is viewed.

8. The device of claim 7, wherein the optical compensation component comprises a film with includes arbitrary periodic patterns of refractive indices.

9. The device of claim 7, wherein the optical compensation component comprises an array of photonic crystals to reduce an angle of incidence that light passing through the optical compensation component makes with the array of interference modulators.

10. The device of claim 7, wherein the optical compensation component comprises a film which includes a plurality of microscopic plates oriented to reduce an angle of incidence that light passing through the optical compensation component makes with the array of interference modulators.

11. The device of claim 10, wherein the film comprises a plurality of layers each comprising microscopic plates oriented to reduce an angle of incidence that light passing through the layer makes with the layer below it.

12. The device of claim 7, wherein the optical compensation component comprises a plurality of microlenses to magnify an active area of the interference modulators in the array.

13. A method for fabricating a reflective display, the method comprising:

fabricating an array of interference modulators, each comprising a primary and a secondary mirror which in a quiescent state is spaced on the primary mirror by a first distance so that light reflected form the modulator is of a first color, and which in a second state, under influence of a biased voltage is spaced from the primary mirror by a second distance which is less than the first distance so that the modulator reflects light of a second color; and

coupling an optical compensation component to the array of interference modulators to compensate for changes in a color of light reflected by the array due to changes in an angle at which the array is viewed.

14. The method of claim 13, wherein the optical compensation component comprises a film with includes arbitrary periodic patterns of refractive indices.

15. The method of claim 13, wherein the optical compensation component comprises an array of photonic crystals to reduce an angle of incidence that light passing through the optical compensation component makes with the array of interference modulators.

16. The method of claim 13, wherein the optical compensation component comprises a film which includes a plurality of microscopic plates oriented to reduce an angle of incidence that light passing through the optical compensation component makes with the array of interference modulators.

17. The method of claim 16, wherein the film comprises a plurality of layers each comprising microscopic plates oriented to reduce an angle of incidence that light passing through the layer makes with the layer below it.

18. The method of claim 13, wherein the optical compensation component comprises a plurality of microscopic lenses to magnify an active area of the interference modulators in the array.