WO2002021205A1 - Reduction d'empreinte dans un systeme de television a projection de fond - Google Patents

Reduction d'empreinte dans un systeme de television a projection de fond Download PDF

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Publication number
WO2002021205A1
WO2002021205A1 PCT/US2001/026100 US0126100W WO0221205A1 WO 2002021205 A1 WO2002021205 A1 WO 2002021205A1 US 0126100 W US0126100 W US 0126100W WO 0221205 A1 WO0221205 A1 WO 0221205A1
Authority
WO
WIPO (PCT)
Prior art keywords
polarized light
mirror
screen
functional
rear projection
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/US2001/026100
Other languages
English (en)
Inventor
Shinjiro Umeya
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sony Electronics Inc
Original Assignee
Sony Electronics Inc
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 Sony Electronics Inc filed Critical Sony Electronics Inc
Priority to AU2001285147A priority Critical patent/AU2001285147A1/en
Publication of WO2002021205A1 publication Critical patent/WO2002021205A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor

Definitions

  • the invention includes a rear projection television system employing a laser projector and having a reduced footprint depth as a result of employing laser light in a particular polarized light form.
  • the small screen of most CRT based televisions does not deliver the big screen experience of the theater primarily due to the technological limitations inherent in the cathode ray tube.
  • the glass display screen of a conventional CRT television generally is limited to less than a forty inch diagonal since the cost and weight of a CRT television increases significantly as the size of the display increases.
  • rear projection television systems were developed to provide viewing screens larger than those provided by CRT based televisions at a cost and weight that is less than even the largest CRT televisions.
  • rear projection television systems provide a large, greater than 40-inch diagonal screen display for viewing, these systems require a significant amount of floor space. For example, most rear projection television systems have a depth of approximately twenty inches so that the system must extend at least twenty inches from a room wall. This footprint dimension generally is too large for many homes.
  • the size of the rear projection television footprint is due mostly to the focus length of the projector lens. That is to say, the light image that leaves the projector lens must travel a specific length or distance before impacting the rear of the display screen so as to be in focus on impacting the display screen. This focus length dictates the length of the optical path. Thus, the optical path length dictates the footprint depth dimension of the rear projection television system.
  • the invention includes an apparatus to produce and transmit a particular form of polarized light so as to be able to reduce the footprint depth of a rear image projection system.
  • the apparatus includes a laser projector that projects a first form of polarized light along an optical path.
  • the apparatus also includes a conversion mirror, a screen having a rear facing the conversion mirror, and a functional mirror located adjacent to the rear of screen and in the optical path between the conversion mirror and the screen.
  • Figure 1 is a front view of rear projection system 100;
  • Figure 2 is a side view of a prior art rear projection system 200;
  • Figure 3 is a side view of system 300 of the invention; and
  • Figure 4 illustrates a plot of a dimension simulation result comparing prior art system 200 against system 300 of the invention.
  • Figure I is a front view of rear projection system 100.
  • Figure 2 is a side view of a prior art rear projection system 200.
  • Figure 2 is provided for comparison to, Figure 3.
  • Figure 3 is a side view of system 300 of the invention.
  • Rear projection system 100 of Figure 1 may display the footprint width and height dimensions of either prior art rear projection system 200 or rear projection system 300 of the invention.
  • rear projection system 100 may define an overall width of 100.0 centimeters (cm) (39.4 inches) and an overall height of 115.0 cm (45.3 inches).
  • the projection screen may define a width and height of 64.0 X 85.3 cm, so as to give a screen diagonal of 106.6 cm (42 inches).
  • the invention is not restricted to these width and height dimensions and may be defined by any industry standard or nonstandard width and height.
  • Prior art rear projection system 200 may define depth 202. Depth 202 may be thought of as a footprint depth dimension of system 200. Here, depth 202 is 50.0 cm (19.7 inches).
  • Prior art rear projection system 200 includes projector 210, mirror 212, and screen 214 housed in cabinet 216. Projector 210 puts forth light waves 218 so that light waves 218 impact mirror 212. Light waves 218 then are reflected from mirror 212 onto the rear of screen 214. The moving images may then be viewed from the front of screen 214.
  • the focus length of the lens within projector 210 determines the optical path length that is required in order to project a focused image onto screen 214.
  • the optical path length of one portion of the light wave 218 is equal to the distance traversed by wave segment 220 plus the distance traversed by wave segment 222.
  • Projector 210 could be located directly behind screen 214 at a distance that is represented by wave segment 220 plus wave segment 222. However, this would result in a maximum footprint depth dimension 202.
  • Footprint depth dimension 202 is shortened by locating projector 210 at the bottom of cabinet 216 and reflecting light waves 218 against pre-positioned mirror 212 and onto the rear of screen 214.
  • the optical path length of one portion of the light wave 218 remains equal to the distance traversed by wave segment 220 plus the distance traversed by wave segment 222, but depth 202 may be reduced to 50.0 cm.
  • Figure 3 is a side view of system 300 of the invention.
  • System 300 may be any rear projection system, such as a rear projection television, oscilloscope, or radar.
  • System 300 may define depth 302.
  • Depth 302 may be thought of as a footprint depth dimension of system 300.
  • depth 302 is less than 50.0 cm (19.7 inches).
  • depth 302 is almost one half of depth 202.
  • depth 302 is 30.0 cm (11.8 inches).
  • system 300 may be laser projector 310, conversion mirror 312, and screen 314 housed in cabinet 316. i addition, system 300 may include functional mirror 319. Functional mirror 319 may be positioned adjacent to the rear of screen 314 in the optical path between conversion mirror 312 and screen 314.
  • Ordinary light may be thought of as being produced by vibrations transverse or perpendicular to the direction of the ray, and distributed so as to show no distinction as to any particular direction.
  • Polarized light may be thought of as light that vibrates in one plane (plane-polarized light), light with a rotary vibration (circular polarized light), or light that vibrates elliptically (elliptically polarized light). For example, when the vibrations of the light are made to take place in one plane, the light is said to be plane polarized. If only a portion of the vibrations lie in one plane the ray is said to be partially polarized.
  • moonlight and skylight are polarized, as is much reflected light, naturally polarized light is, on the whole, rather imperfectly polarized.
  • Laser projector 310 may be any device that converts incident electromagnetic radiation of mixed frequencies to one or more discrete frequencies of highly amplified and coherent ultraviolet, visible, or infrared radiation and projects this radiation.
  • laser projector 310 may put forth one of two discrete forms of light: p- polarized light and s-polarized light. The letters "p” and "s” are used in this patent to distinguish each polarization of light and represents no independent meaning.
  • p-polarized light (or s-polarized light) has a short optical path length than ordinary light passing through that same lens.
  • depth 302 of system 300 may be range over a shorter distance than depth 202 of system 200.
  • the footprint depth dimension of system 300 may be reduced over a conventional rear projection system, such as system 200 of Figure 2.
  • Functional mirror 319 may include a surface capable of reflecting a first form of polarized light while transmitting a second form of polarized light from laser projector 310. Accordingly, when light waves
  • functional mirror 319 impacts functional mirror 319, the first form of polarized light is reflected towards conversion mirror 312. The expected 80%+ efficiency of this reflection may be viewed as high since the polarization of functional mirror 319 is set to match the polarization of light waves 318 incident thereon.
  • functional mirror 319 reflects p- polarized light and transmits s-polarized light.
  • functional mirror 319 reflects p- polarized light and transmits s-polarized light.
  • Conversion mirror 312 may include quarter- wave plate 320 disposed in front of
  • Quarter-wave plate 320 (sometimes written ⁇ /4 plate) may be a plate or series of plates that, along with reflection mirror 322, may be adapted to convert the first form of polarized light to the second form of polarized light.
  • Reflection mirror 322 may include a surface capable of reflecting the second form of polarized light back towards functional mirror 319.
  • quarter-wave plate 320 may convert an incoming plane-polarized light (p-polarized light) to clockwise circular polarized light.
  • Reflection mirror 322 may convert the clockwise circular polarized light to counterclockwise circular polarized light.
  • quarter- wave plate 320 may convert the counterclockwise circular polarized light into s-polarized light. This second form of polarized light may then become incident on functional mirror 319.
  • Figure 4 illustrates a plot of a dimension simulation result comparing prior art system 200 against system 300 of the invention.
  • rear projection system set depth is plotted as a function of set height.
  • set depth decreases.
  • depth 302 of system 300 may be much less (approximately 3/5 less) than depth 202 of system 200 for a set height of 112 cm (44 inches).
  • the footprint depth dimension difference becomes more pronounce.
  • depth 302 of system 300 may be as much as 1/2 of depth 202 of system 200.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Projection Apparatus (AREA)
  • Transforming Electric Information Into Light Information (AREA)

Abstract

L'invention concerne un dispositif permettant de produire et de transmettre une forme particulière de lumière polarisée qui entraîne la réduction de la profondeur d'empreinte dans un système de télévision à projection de fond. Le dispositif comprend un projecteur laser (310) qui projette une première forme de lumière polarisée le long d'un trajet optique, un miroir de conversion (312), un écran (314) dont l'arrière fait face au miroir de conversion (312), et un miroir fonctionnel (319) adjacent à l'arrière de l'écran (314) et situé dans le trajet optique entre le miroir de conversion (312) et l'écran (314).
PCT/US2001/026100 2000-09-08 2001-08-20 Reduction d'empreinte dans un systeme de television a projection de fond Ceased WO2002021205A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001285147A AU2001285147A1 (en) 2000-09-08 2001-08-20 Footprint reduction in a rear projection television system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US65805300A 2000-09-08 2000-09-08
US09/658,053 2000-09-08

Publications (1)

Publication Number Publication Date
WO2002021205A1 true WO2002021205A1 (fr) 2002-03-14

Family

ID=24639715

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2001/026100 Ceased WO2002021205A1 (fr) 2000-09-08 2001-08-20 Reduction d'empreinte dans un systeme de television a projection de fond

Country Status (2)

Country Link
AU (1) AU2001285147A1 (fr)
WO (1) WO2002021205A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8873144B2 (en) 2011-05-17 2014-10-28 Moxtek, Inc. Wire grid polarizer with multiple functionality sections
US8913320B2 (en) 2011-05-17 2014-12-16 Moxtek, Inc. Wire grid polarizer with bordered sections
US8913321B2 (en) 2010-09-21 2014-12-16 Moxtek, Inc. Fine pitch grid polarizer
US8922890B2 (en) 2012-03-21 2014-12-30 Moxtek, Inc. Polarizer edge rib modification
US9348076B2 (en) 2013-10-24 2016-05-24 Moxtek, Inc. Polarizer with variable inter-wire distance

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4969732A (en) * 1988-02-25 1990-11-13 Thorn Emi Plc Display device
US6181386B1 (en) * 1995-12-29 2001-01-30 Duke University Projecting images
US6276802B1 (en) * 1998-04-17 2001-08-21 Seiko Epson Corporation Rear projection display
US6318862B1 (en) * 1997-06-10 2001-11-20 Thomson Multimedia Projection system employing multiple beam reflections

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4969732A (en) * 1988-02-25 1990-11-13 Thorn Emi Plc Display device
US6181386B1 (en) * 1995-12-29 2001-01-30 Duke University Projecting images
US6318862B1 (en) * 1997-06-10 2001-11-20 Thomson Multimedia Projection system employing multiple beam reflections
US6276802B1 (en) * 1998-04-17 2001-08-21 Seiko Epson Corporation Rear projection display

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8913321B2 (en) 2010-09-21 2014-12-16 Moxtek, Inc. Fine pitch grid polarizer
US8873144B2 (en) 2011-05-17 2014-10-28 Moxtek, Inc. Wire grid polarizer with multiple functionality sections
US8913320B2 (en) 2011-05-17 2014-12-16 Moxtek, Inc. Wire grid polarizer with bordered sections
US8922890B2 (en) 2012-03-21 2014-12-30 Moxtek, Inc. Polarizer edge rib modification
US9348076B2 (en) 2013-10-24 2016-05-24 Moxtek, Inc. Polarizer with variable inter-wire distance
US9354374B2 (en) 2013-10-24 2016-05-31 Moxtek, Inc. Polarizer with wire pair over rib
US9632223B2 (en) 2013-10-24 2017-04-25 Moxtek, Inc. Wire grid polarizer with side region

Also Published As

Publication number Publication date
AU2001285147A1 (en) 2002-03-22

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