WO2005120081A1 - Light engine architecture - Google Patents

Light engine architecture Download PDF

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Publication number
WO2005120081A1
WO2005120081A1 PCT/US2005/018520 US2005018520W WO2005120081A1 WO 2005120081 A1 WO2005120081 A1 WO 2005120081A1 US 2005018520 W US2005018520 W US 2005018520W WO 2005120081 A1 WO2005120081 A1 WO 2005120081A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
red
projection path
green
projection
Prior art date
Application number
PCT/US2005/018520
Other languages
French (fr)
Inventor
Jr. Estill Thone Hall
Original Assignee
Thomson Licensing
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomson Licensing filed Critical Thomson Licensing
Publication of WO2005120081A1 publication Critical patent/WO2005120081A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/14—Beam splitting or combining systems operating by reflection only
    • G02B27/145—Beam splitting or combining systems operating by reflection only having sequential partially reflecting surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
    • G02B27/102—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources
    • G02B27/1026—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources for use with reflective spatial light modulators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3102—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators
    • H04N9/3105—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems

Definitions

  • This invention is related to projection systems for displays.
  • Projection systems for displays typically utilize a light source such as an ultra-high pressure (UHP) mercury vapor arc lamp.
  • UHP ultra-high pressure
  • the light from the lamp is separated into red, green, and blue components, which are then modulated by an input image signal and projected.
  • a light engine having: a first light source radiating white light along a first projection path, a first filter disposed in the first projection path removing a red light component from the light, blue and green imagers disposed in the first projection path, modulating blue and green components of light, a second light source radiating white light with high red content along a second projection path, a second filter disposed in the second projection path removing blue and green light components, and a red imagcr disposed in the second projection path for modulating a red light component, wherein the first projection path and the second projection path merge after the light components arc modulated.
  • one light source provides the blue and green light, which is modulated and projected
  • a different light source provides red light, which is modulated and projected, and all of the light components (r,b,g) are merged prior to projection.
  • Fig. 1 is a schematic view of a projection system according to an exemplary embodiment of the present invention
  • Fig. 2 is a schematic view of a projection system according to another exemplary embodiment of the present invention.
  • white (UHP) light 1 enters a projection system from the bottom of the figure as shown.
  • the white light 1 in the exemplary embodiment is radiated by a UHP lamp 10 and is pre-polarized to be of "s" linear polarization.
  • the light then passes through a Red Cyan ColorSelectTM 12 which changes all red light components to "p" polarization, while blue and green light components remain “s” polarization.
  • the light then strikes an "s” reflective polarizer 14 which reflects the "p" light (in the instant case, red) back toward the first lamp 10.
  • the Blue & Green light, being “s” pass through the "s” polarizer 14, unaltered.
  • the Blue & Green light then passes through a Green/Magenta ColorSclcctTM 16, which converts the green light from “s” to “p” and leaves the blue light unchanged as “s”.
  • the Blue and Green light then enter a PBS (polarizing beam splitter) I N where the blue light is reflected toward a blue imager 20 (since it is “s") while the green light is transmitted toward the green imager 22 (since it is "p”).
  • the blue imager 20, along with the other imagers disclosed, may be for example a liquid crystal on silicone (LCOS) imager.
  • LCOS liquid crystal on silicone
  • the blue light component entering the blue imager 20 is rotated by 90 degrees in polarization, thus, the light coming out of the blue imager is converted to "p".
  • the green light coming out of the green imager 22 is converted to "s".
  • Both the blue and green light components reach the selective transmission interface of the PBS 18 again, and the blue "p"' light is transmitted, while the green "s” light is reflected, thus recombining them. They then pass through a second green/magenta ColorSelectTM 24, changing the green "s” light to "p” and leaving the blue “p” light unchanged. Since both the green and blue light components are "p” polarization, they pass straight through another PBS 40 adjacent the second green/magenta ColorSelect M 24. They then pass through a Red/Cyan ColorSelect TM
  • a light with high red content 2 enters the system from the upper left, as shown in Figure 1.
  • the light with high red content 2 may be radiated for example by a second light source 30.
  • the light with high red content 2 is polarized to be "s" light by a reflective S-polarizer 32, which reflects the "p" light back toward the source of the light 30.
  • a beam of white (with high red content) "s” light is transmitted through the reflective S- polarizer 32.
  • This "s” light passes through a Red/Cyan color selectTM 34, making the red light component "p” polarization, and the cyan (blue and green) light remains “s” polarization.
  • the "p” red light component and the "s" blue and green light components enter a PBS 36 adjacent the Red/Cyan color selectTM 34.
  • the Cyan light 2BG is reflected upward out of the system as waste light.
  • the red light (being "p") passes through the PBS and strikes a red imager 38. If the imager is "on”, the polarization is rotated 90 degrees, and re-enters the PBS as "s” light. This is reflected downward at the PBS interface.
  • This red “s” light then enters the PBS 40 subjacent the PBS 36 and reflects from the lower PBS interface, to join the green and blue light components from the first light source 10.
  • the red light component enters the red/cyan ColorSelectTM 42, where it is rotated to become "p" polarization, and then projected by the projection lens 50.
  • the net result is r, g, b light all projected as "p" polarization light, towards a projection screen (not shown).
  • the embodiment of Figure 2 is similar to that of Figure 1 except for the way in which unwanted light colors from the respective first 10 and second 30 light sources are filtered out of the projection system upon injection.
  • the red light is stripped from the (UHP) light 1 using a dichroic filter 1 12, which transmits cyan and reflects red.
  • the light at the high red source 30 is separated by a dichroic filter 134, which transmits red and reflects cyan.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Projection Apparatus (AREA)

Abstract

A light engine is provided having: a first light source radiating white light along a first projection path, a first filter disposed in the first projection path removing a red light component from the light, blue and green imagers disposed in the first projection path, modulating blue and green components of light, a second light source radiating white light with high red content along a second projection path, a second filter disposed in the second projection path removing blue and green light components, and a red imager disposed in the second projection path for modulating a red light component, wherein the first projection path and the second projection path merge after the light components are modulated.

Description

LIGHT ENGINE ARCHITECTURE
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U. S. Provisional Patent Application Serial No. 60/574,605, entitled "New Light Engine Architecture " and filed May 26, 2004, which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
This invention is related to projection systems for displays.
BACKGROUND OF THE INVENTION
Projection systems for displays typically utilize a light source such as an ultra-high pressure (UHP) mercury vapor arc lamp. The light from the lamp is separated into red, green, and blue components, which are then modulated by an input image signal and projected. A problem exists with using these light sources in that they are generally deficient in red light. SUMMARY OF THE INVENTION
Two systems are disclosed which use a separate source for red light and combine them at the appropriate moment. A light engine is provided having: a first light source radiating white light along a first projection path, a first filter disposed in the first projection path removing a red light component from the light, blue and green imagers disposed in the first projection path, modulating blue and green components of light, a second light source radiating white light with high red content along a second projection path, a second filter disposed in the second projection path removing blue and green light components, and a red imagcr disposed in the second projection path for modulating a red light component, wherein the first projection path and the second projection path merge after the light components arc modulated. Thus, one light source provides the blue and green light, which is modulated and projected, and a different light source provides red light, which is modulated and projected, and all of the light components (r,b,g) are merged prior to projection.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the invention will be described with reference to the accompanying drawing figures, of which: Fig. 1 is a schematic view of a projection system according to an exemplary embodiment of the present invention; and Fig. 2 is a schematic view of a projection system according to another exemplary embodiment of the present invention.
DETAILED DESCRIPTION In the embodiment of Figure 1 , white (UHP) light 1 enters a projection system from the bottom of the figure as shown. The white light 1 in the exemplary embodiment is radiated by a UHP lamp 10 and is pre-polarized to be of "s" linear polarization. The light then passes through a Red Cyan ColorSelect™ 12 which changes all red light components to "p" polarization, while blue and green light components remain "s" polarization. The light then strikes an "s" reflective polarizer 14 which reflects the "p" light (in the instant case, red) back toward the first lamp 10. The Blue & Green light, being "s" pass through the "s" polarizer 14, unaltered. The Blue & Green light then passes through a Green/Magenta ColorSclcct™ 16, which converts the green light from "s" to "p" and leaves the blue light unchanged as "s". The Blue and Green light then enter a PBS (polarizing beam splitter) I N where the blue light is reflected toward a blue imager 20 (since it is "s") while the green light is transmitted toward the green imager 22 (since it is "p"). The blue imager 20, along with the other imagers disclosed, may be for example a liquid crystal on silicone (LCOS) imager. If the imager is "on" (i.e., the modulation signal is indicative of a bright image for blue) the blue light component entering the blue imager 20 is rotated by 90 degrees in polarization, thus, the light coming out of the blue imager is converted to "p". Similarly, the green light coming out of the green imager 22 is converted to "s". Both the blue and green light components reach the selective transmission interface of the PBS 18 again, and the blue "p"' light is transmitted, while the green "s" light is reflected, thus recombining them. They then pass through a second green/magenta ColorSelect™ 24, changing the green "s" light to "p" and leaving the blue "p" light unchanged. Since both the green and blue light components are "p" polarization, they pass straight through another PBS 40 adjacent the second green/magenta ColorSelect M 24. They then pass through a Red/Cyan ColorSelect TM
42, which also transmits them unaltered, and they are projected by a projection lens 50. Meanwhile, a light with high red content 2 enters the system from the upper left, as shown in Figure 1. The light with high red content 2 may be radiated for example by a second light source 30. The light with high red content 2 is polarized to be "s" light by a reflective S-polarizer 32, which reflects the "p" light back toward the source of the light 30. A beam of white (with high red content) "s" light is transmitted through the reflective S- polarizer 32. This "s" light passes through a Red/Cyan color select™ 34, making the red light component "p" polarization, and the cyan (blue and green) light remains "s" polarization. The "p" red light component and the "s" blue and green light components enter a PBS 36 adjacent the Red/Cyan color select™ 34. At the PBS interface, the Cyan light 2BG is reflected upward out of the system as waste light. The red light (being "p") passes through the PBS and strikes a red imager 38. If the imager is "on", the polarization is rotated 90 degrees, and re-enters the PBS as "s" light. This is reflected downward at the PBS interface. This red "s" light then enters the PBS 40 subjacent the PBS 36 and reflects from the lower PBS interface, to join the green and blue light components from the first light source 10. The red light component enters the red/cyan ColorSelect™ 42, where it is rotated to become "p" polarization, and then projected by the projection lens 50. The net result is r, g, b light all projected as "p" polarization light, towards a projection screen (not shown). The embodiment of Figure 2 is similar to that of Figure 1 except for the way in which unwanted light colors from the respective first 10 and second 30 light sources are filtered out of the projection system upon injection. In this case, the red light is stripped from the (UHP) light 1 using a dichroic filter 1 12, which transmits cyan and reflects red. The light at the high red source 30 is separated by a dichroic filter 134, which transmits red and reflects cyan. The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.

Claims

CLAIMS 1. A light engine comprising: a first light source radiating white light along a first projection path; a first filter disposed in the first projection path removing a red light component from the light; blue and green imagers disposed in the first projection path, modulating blue and green components of light; a second light source radiating white light with high red content along a second projection path; a second filter disposed in the second projection path removing blue and green light components; and a red imager disposed in the second projection path for modulating a red light component; wherein the first projection path and the second projection path merge after the light components are modulated.
2. The light engine of claim 1, wherein the first filter comprises a Red/Cyan ColorSelect™ and an "s" reflective polarizer adjacent the Red/Cyan ColorSelect™.
3. The light engine of claim 1, wherein the second filter comprises an "s" reflective polarizer, a Red/Cyan ColorSelect™ adjacent the "s" reflective polarizer, and a PBS adjacent the Red/Cyan ColorSelect™.
4. The light engine of claim 1, wherein the first filter comprises a cyan dichroic filter.
5. The light engine of claim 1, wherein the second filter comprises an "s" reflective polarizer and a red dichroic filter.
6. The light engine of claim 1 , further comprising: A green/magenta ColorSelect™ and a first PBS disposed in series along the first projection path between the first filter and the blue and green imagers; and a second green/magenta ColorSelect™ disposed along the first projection path after the first PBS.
7. The light engine of claim 6, further comprising a second red/cyan ColorSelect™ and a second PBS disposed in series along the first projection path between the second filter and the red imager.
8. The light engine of claim 7, further comprising: a third PBS disposed at a junction of the first and second projection paths, merging the two projection paths; a third red/cyan ColorSelect™ disposed along the first and second projection paths subsequent the third PBS; and a projection lens disposed along the first and second projection paths subsequent the third red/cyan ColorSelect™.
PCT/US2005/018520 2004-05-26 2005-05-25 Light engine architecture WO2005120081A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US57460504P 2004-05-26 2004-05-26
US60/574,605 2004-05-26

Publications (1)

Publication Number Publication Date
WO2005120081A1 true WO2005120081A1 (en) 2005-12-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2005/018520 WO2005120081A1 (en) 2004-05-26 2005-05-25 Light engine architecture

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0537708A1 (en) * 1991-10-15 1993-04-21 Canon Kabushiki Kaisha Colour projector
US5394204A (en) * 1992-08-21 1995-02-28 Matsushita Electric Industrial Co., Ltd. Projection type image display device
US20020067468A1 (en) * 2000-12-01 2002-06-06 O'connor Michael Enhancing spectral luminosity in projection displays
EP1499136A1 (en) * 2003-07-14 2005-01-19 Sony International (Europe) GmbH Illumination unit, projection engine and method for generating illumination light

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0537708A1 (en) * 1991-10-15 1993-04-21 Canon Kabushiki Kaisha Colour projector
US5394204A (en) * 1992-08-21 1995-02-28 Matsushita Electric Industrial Co., Ltd. Projection type image display device
US20020067468A1 (en) * 2000-12-01 2002-06-06 O'connor Michael Enhancing spectral luminosity in projection displays
EP1499136A1 (en) * 2003-07-14 2005-01-19 Sony International (Europe) GmbH Illumination unit, projection engine and method for generating illumination light

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