Linear spatial light modulator and printer

• US 4,596,992 A
• Filed: 08/31/1984
• Issued: 06/24/1986
• Est. Priority Date: 08/31/1984
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Hornbeck, Larry J.
• Primary Examiner(s): Goldberg, E. A.
• Assistant Examiner(s): EVANS, ARTHUR G
• Application Number:
  US06/646,399
• Time in Patent Office: 662 Days
• Field of Search: 346/107 R, 346/155, 346/160, 350/360, 350/356, 358/300
• US Class Current: 347/134
• CPC Class Codes: B41J 2/465 using masks, e.g. light-switching masks
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 7/1827 Motorised alignment
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices
• CPC Class Codes: G06K 15/1252 using an array of light modulators, e.g. a linear array
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]

Abstract

A linear spatial light modulator with two offset rows of pixels for slight overlap of images, and a printer system using such a spatial light modulator with dark field projection optics is disclosed. The pixels include electrostatically deflectable elements which all bend in the same direction to permit use of dark field projection. The addressing electrodes for the elements are beneath the reflecting surface and arranged perpendicular to the rows of pixels with half on each side of the rows. The printer uses a xerographic engine for conversion of modulated light into print, and an entire row is printed without any scanning.

Claims

1. A linear spatial light modulator, comprising:

(a) a plurality of pixels formed in a layered structure, said pixels arranged substantially in a line;

(b) said layered structure including a substrate, a rigid insulating spacer layer on said substrate, a conducting reflecting layer on said spacer layer, and electrical addressing circuitry;

(c) each of said pixels including;

(i) an electrostatically deflectable element formed in said reflecting layer, and

(ii) a well formed in said spacer layer and located beneath said deflectable element plus adjacent portions of said reflecting layer, said well characterized by formation by plasma etching of said spacer between said substrate and said reflecting layer; and

(d) said addressing circuitry including a plurality of electrodes between said substrate and said spacer layer, said electrodes insulated from said substrate and from each other and arranged substantially perpendicular to said line, each of said electrodes extending from the bottom of one of said wells to one of a plurality of pass transistors located away from said line and beneath said spacer layer.

2. The linear spatial light modulator of claim 1, wherein:

(a) said circuitry further includes a shift register on said substrate with outputs to said pass transistors.

3. A linear spatial light modulator, comprising:

(a) a plurality of pixels arranged substantially in a line on a substrate;

(b) each of said pixels including an electrostatically deflectable element supported away from said substrate by a conducting post narrower than said element'"'"'s width;

(c) a plurality of electrodes on said substrate and arranged substantially perpendicular to said line, each of said electrodes extending from beneath one of said deflectable elements to a pass transistor located away from said line; and

a plurality of conductors on said substrate insulated from said electrodes and electrically connecting said posts.

4. The linear spatial light modulator of claim 3, further comprising:

(a) a shift register on said substrate with outputs to said pass transistors.

5. A nonimpact printer, comprising:

(a) a light source;

(b) a first optical system to focus light from said light source onto the linear optically active area of a linear spatial light modulator;

(c) said linear spatial light modulator including a plurality of pixels arranged substantially in a line in a layered structure to form said optically active area, said layered structure including a substrate, a rigid insulating spacer layer on said substrate, a conducting reflecting layer on said spacer layer, and each of said pixels including an electrostatically deflectable element formed in said reflecting layer and a well formed in said spacer layer and located beneath said deflectable element and characterized by plasma etching of said spacer between said substrate and said reflecting layer;

(d) addressing circuitry on said substrate for converting electrical signals into deflectable element deflections; and

(e) a second optical system for foucssing the light reflected from the deflected ones of said deflectable elements onto a xerographic drum, said second optical system characterized by the image of said linear optically active area being a linear region parallel to the axis of said drum.

6. The nonimpact printer of claim 5, wherein:

(a) said deflectable elements all deflect in the same direction; and

(b) said second optical system includes a dark field projection system.

7. The nonimpact printer of claim 5, wherein:

(a) said deflectable elements form two offset rows; and

(b) said addressing circuitry includes a plurality of electrodes arranged substantially perpendicular to said line and formed into two groups, an electrode from a first of said groups extending from under one of said deflectable elements in a first of said rows in a first direction, and an electrode from the second of said groups extending from under one of said defelctable elements in the second of said rows in a direction opposite said first direction.

8. The nonimpact printer of claim 5, wherein:

(a) each of said pixels including at least two deflectable elements arranged in a direction perpendicular to said line.