Method and apparatus for interferometric modulation of light

• US 6,466,354 B1
• Filed: 09/19/2000
• Issued: 10/15/2002
• Est. Priority Date: 09/19/2000
• Status: Expired due to Fees

• Current Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Original Assignee: Silicon Light Machines Corporation (SCREEN Holdings Co., Ltd.)
• Inventors: Gudeman, Christopher
• Primary Examiner(s): Schwartz, Jordan
• Assistant Examiner(s): CHOI, WILLIAM C
• Application Number:
  US09/664,020
• Time in Patent Office: 756 Days
• Field of Search: 359/656-661, 359/672, 359/673, 359/675, 359/802, 359/803, 359/104, 359/237, 359/240, 359/244-248, 359/254, 359/261, 359/263, 359/265, 359/273, 359/290, 359/291, 359/295, 359/296, 359/298, 250/227-4-2, 256/450, 382/211
• US Class Current: 359/247
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• 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: G02F 1/21 by interference
• CPC Class Codes: G02F 1/213 Fabry-Perot type

Abstract

An interferometric light modulator includes a base and a ribbon suspended above the base. The ribbon has a central region and first and second conducting regions located outside of the central region. The ribbon includes a first mirror between the first and second conducting regions. The base includes a second mirror located parallel and adjacent to the first mirror so that the first and second mirrors form an interferometric cavity. An electrical bias applied to the first and second conducting regions adjusts the interferometric cavity in order to modulate light which is incident upon the central region of the ribbon. In an alternative interferometric light modulator, the light is incident upon a second central region of the base.

Claims

1. An interferometric light modulator comprising:

a. a base;

b. a beam suspended above the base and having first and second ends, a first conductive region proximate the first end of the beam, a second conductive region proximate the second end of the beam; and

c. means for biasing the first and second conductive regions relative to the base such that the base and the beam form an interferometric cavity and further such that light entering the interferometric cavity is modulated in response to the means for biasing, wherein the beam comprises an entrance window for the light and further wherein the base comprises an exit window for the light.

2. An interferometric light modulator comprising:

a. a base;

b. a beam suspended above the base and having first and second ends, a first conductive region proximate the first end of the beam, a second conductive region proximate the second end of the beam; and

c. means for biasing the first and second conductive regions relative to the base such that the base and the beam form an interferometric cavity and further such that light entering the interferometric cavity is modulated in response to the means for biasing, wherein the beam comprises an entrance window for the light and the beam comprises an exit window for the light.

3. An interferometric light modulator comprising:

a. a base comprising a semiconductor substrate;

b. a beam suspended above the base and having first and second ends, a first conductive region proximate the first end of the beam, a second conductive region proximate the second end of the beam; and

c. means for biasing the first and second conductive regions relative to the base such that the base and the beam form an interferometric cavity and further such that light entering the interferometric cavity is modulated in response to the means for biasing.

4. The interferometric light modulator of claim 3 wherein the semiconductor substrate comprises a silicon substrate.

5. A light modulator comprising:

a. a semiconductor substrate;

b. a flexible beam suspended above the semiconductor substrate, the flexible beam having a central portion located between first and second ends, the beam having first and second electrical conducting layers, the first electrical conducting layer located between the first end and the central portion of the flexible beam, the second electrical conducting layer located between the central portion and the second end of the flexible beam; and

means for electrically biasing the first and second electrical conducting layers relative to the semiconductor substrate such that a distance between the central portion of the flexible beam and the semiconductor substrate is variable and further such that the central portion of the flexible beam and the semiconductor substrate form a variable interference cavity for light.

6. A light modulator comprising:

a. a base comprising a semiconductor substrate;

b. a ribbon suspended above the base and having a central region and first and second conducting regions located outside of the central region; and

c. means for biasing the first and second conducting regions such that a distance between the central region of the ribbon and the base is variable and further such that the central region of the ribbon and the base forms a variable interference cavity for light.

7. A light modulator comprising:

a. a base comprising a semiconductor substrate and having first and second conductive regions, the first conductive region coupled to the second conductive region;

b. a ribbon suspended above the base and having a central portion and third and fourth conductive regions located outside of the central region, the third conductive region coupled to the fourth conductive region such that an electrical bias applied to the third and fourth conductive regions relative to the first and second conductive regions varies a distance between the central portion of the ribbon and the base and further such that the central portion of the ribbon and the base form a variable interference cavity for light.