Display system

• US 6,276,801 B1
• Filed: 04/28/1997
• Issued: 08/21/2001
• Est. Priority Date: 08/04/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Digital Projection Limited
• Inventors: Fielding, Raymond G.
• Primary Examiner(s): DOWLING, WILLIAM C
• Application Number:
  US08/776,805
• Time in Patent Office: 1,576 Days
• Field of Search: 353/20, 353/30, 353/31, 353/33, 353/34, 353/37, 353/99, 353/84, 348/771, 348/742, 348/743, 348/750, 348/755, 348/770, 345/31, 345/32, 345/108
• US Class Current: 353/31
• 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: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/3114 by using a sequential colour filter producing one colour at a time

Abstract

A projecting display system includes a light source (101) which produces light which is spatially modulated by a number of spatial light modulators (105, 107). A splitting means (103) is provided in the light path between the light source (101) and the spatial light modulators (105 and 107) such that the overall luminous flux produceable by the system is not determined by the maximum luminous flux which each spatial light modultors (105, 107) can accommodate.

Claims

1. A display system comprising:

a multi wavelength light source;

a plurality of deflectable mirror devices, each device having a plane defined by an array of mirror elements, each mirror element corresponding to a respective pixel of a color image to be displayed and being deflectable between a first orientation relative to said plane of the array effective to reflect light incident on the mirror element at a predetermined angle not normal to the plane of the array along an “

ON”

path for the device and a second orientation relative to said plane of the array effective to reflect light incident on the mirror element at said predetermined angle along an “

OFF”

path for the device;

input circuitry for receiving signals representative of a color image;

control means for supplying address signals to each device representative of a wavelength band component of said color image and effective to control the orientation of each of the mirror elements of each array between said first and second orientations dependent on said color image, the control means being arranged to supply the same address signals corresponding to at least one of said wavelength band components to at least two of said deflectable mirror devices;

a wavelength selective means for splitting light from said light source within each of said different wavelength band components of said color image;

means for further splitting the light in said one wavelength band component between said at least two deflectable mirror devices;

means for directing the split and further split light in each wavelength band component towards the correspondingly addressed deflectable mirror device; and

means for combining the light reflected by all of the deflectable mirror devices along the respective “

ON”

paths for the devices to form a single spatially modulated light beam.

2. A display system according to claim 1 wherein said means for further splitting light comprises at least one polarized splitter effective to split the light incident thereon into P-polarized light and S-polarized light components.

3. A display system according to claim 1 wherein said means for further splitting the light comprises:

at least one semi-reflective means which is effective to reflect part of the light incident thereon and to transmit the rest of the light incident thereon.

4. A display system according to claim 1 wherein said means for further splitting the light comprises a dichroic means effective to split light within two different narrow wavelength bands within a broad wavelength band including said narrow wavelength bands.

5. A display system according to claim 4 wherein the same wavelength band component is a primary color wavelength band component and said dichroic means is arranged to split light within two different wavelength bands within said primary color band.

6. A display system according to claim 5 in which there are provided at least two spatial light modulators in respect of two different wavelength bands in the green light wavelength band component.