WO1986000685A1 - Reflecteur de systeme d'illumination - Google Patents

Reflecteur de systeme d'illumination Download PDF

Info

Publication number
WO1986000685A1
WO1986000685A1 PCT/US1985/001254 US8501254W WO8600685A1 WO 1986000685 A1 WO1986000685 A1 WO 1986000685A1 US 8501254 W US8501254 W US 8501254W WO 8600685 A1 WO8600685 A1 WO 8600685A1
Authority
WO
WIPO (PCT)
Prior art keywords
aperture
axis
reflector
uniformity
light
Prior art date
Application number
PCT/US1985/001254
Other languages
English (en)
Inventor
Ralph J. Gagnon
Original Assignee
Hughes Aircraft Company
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 Hughes Aircraft Company filed Critical Hughes Aircraft Company
Priority to KR1019860700149A priority Critical patent/KR860700283A/ko
Publication of WO1986000685A1 publication Critical patent/WO1986000685A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V7/00—Reflectors for light sources
    • F21V7/04—Optical design
    • F21V7/08—Optical design with elliptical curvature
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09B—EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS
    • G09B9/00—Simulators for teaching or training purposes
    • G09B9/02—Simulators for teaching or training purposes for teaching control of vehicles or other craft
    • G09B9/08—Simulators for teaching or training purposes for teaching control of vehicles or other craft for teaching control of aircraft, e.g. Link trainer
    • G09B9/30—Simulation of view from aircraft
    • G09B9/308—Simulation of view from aircraft by LCD, gas plasma display or electroluminescent display

Definitions

  • the present invention relates to an improved reflector for use in illumination systems and, in particular, the use of the reflector in liquid crystal light valve projectors.
  • Wilkinson U.S. Patent No. 3,720,460 improves upon the system disclosed in the aforementioned patent by using a surface of revolution constituting a single elliptical segment reflector with its axis displaced to a predetermined angle ⁇ related to: 1) the interfocal distance of the reflector, and 2) the aperture size to produce predetermined intensity across the illuminated aperture.
  • the objectives are achieved by the rotation of the segment of an ellipse constituting a reflector surface about the generating axis of the ellipse passing through the first focus and at such an angle that a ring of foci circumscribes the aperture illuminated by the light source and reflector.
  • the Wilkinson lamp reflector provides a predetermined intensity distribution across an illuminated aperture, such as the film gate aperture of a movie projection system, the uniformity and efficiency levels required for certain applications, such as the liquid crystal light valve projection system described hereinabove, is not achieved by the Wilkinson reflector. Further, additional optical components, including a relay lens, may be required in the Wilkinson system to project the image onto the aperture, thus reducing overall system efficiency.
  • an improved illumination system reflector in which the uniformity of the illumination distribution across an aperture is substantially increased over prior art systems and wherein the overall collector efficiency of the system in which the reflector is utilized is also increased.
  • the present invention relates to an illumination system reflector which provides increased energy to an aperture with high uniformity and at high efficiencies, the reflector being particularly adapted for use in liquid crystal light valve projection systems.
  • a discharge lamp is utilized in conjunction with an elliptical reflector, the axis of the reflector between the primary and secondary focus being tilted at an angle to the lamp axis.
  • the axis of the ellipse is displaced from (hereinafter also called “vertically displaced” for ease of description relative to the drawings) the lamp axis a predetermined amount, the combination of tilt and vertical displacement being effective to increase illumination uniformity and efficiency at the system aperture.
  • FIG. 1 illustrates the prior art Wilkinson system
  • FIG. 2 shows a cross-section of the reflector constructed in accordance with teachings of the present invention
  • FIG. 3 illustrates a negatively decentered ellipse segment
  • FIG. 4 shows the curve segment of FIG. 3
  • FIG. 5 shows a cross-section of a reflector formed in accordance with the teachings of the present invention
  • FIG. 6 illustrates the geometry for computing the source image displacement provided by a shaped lamp envelope
  • FIGS. 7a and 7b illustrate a computer simulation of a full reflector cross-section and an arc lamp utilized in conjunction therewith.
  • FIG. 1 illustrates the prior art Wilkinson projection light source and optical system.
  • a reflector 10 nearly ellipsoidal in shape, has a light source 13 comprising the arc from a gas discharge lamp having a significant length L and located at the first focus f as illustrated.
  • the reflector 10 actually is a surface of revolution of the line S around the axis A of the reflector.
  • the line S is a segment of an ellipse with its major axis M passing through the first focus f and intersecting the axis A at a deviation angle' ⁇ .
  • the second focus of the ellipsoidal shape reflector 10 is not a single point but a ring of foci f2M lying in the plane P.
  • the angle ⁇ is selected to be equal to an angle whose tangent substantially equals one half the maximum transverse dimension of an associated aperture 15 over the interfocal distance of the ellipse.
  • deviation angle ⁇ ranges from 1/2 to 3°.
  • the system Given the parameters of the system including the light source radiance gradient, arc length L and rotation angle ⁇ , the system provides light energy through the aperture 15 at a relatively uniform intensity.
  • the present invention improves upon the Wilkinson system by increasing both collection efficiency and the uniformity of energy distribution at an aperture in the manner hereinafter described.
  • variable parameters are fixed by the constraints imposed upon the illumination reflector system, i.e., the aperture size may be pre ⁇ determined as well as the throw distance by the physical configuration of the system in which the reflector is utilized.
  • a computer program for simulating the reflector design can be utilized to optimize the variable parameters to provide, based on certain given input parameters, a reflector which optimizes collection efficiency and illumination uniformity, it has been found that appropriate values for one of the variable parameters, the vertical displacement of the ellipse axis from the lamp, or optical axis, will significantly increase efficiency and uniformity notwithstanding the values chosen for the other parameters (within pre- determined limits).
  • appropriate selection of the variable tilt parameter will also enhance system performance.
  • FIG. 2 shows a cross-section of a portion of a reflector 18 and a curve 20 which is a segment of an ellipse.
  • the geometry utilized in constructing the reflector 18 in accordance with the teachings of the present invention is also shown.
  • the intersection point 21 of the ellipse axis 22 and the reflector portion 20 is raised (decentered) by distance DH above the system optical axis (i.e., the major ellipse is displaced an amount DH from optical axis A) .
  • the ellipse portion 20 is rotated about the optical axis A at an angle ⁇ about the left side axial intercept.
  • the curve 20 above the tilted ellipse axis 22 is then a partial cross-section of the solid reflector.
  • the surface of revolution thus is a section of an ellipse that has been tilted, decentered and then rotated about the optical axis.
  • FIG. 2 indicates that decentration occurs above the optical axis A, the ellipse is preferably placed below the optical axis (negative decentration) to bring illumination source 26 closer to the curve of the ellipse.
  • FIG. 5 shows, for illustrative purposes, a drawing (not completely to scale) of a reflector cross-section fabricated in accordance with the teachings of the present invention with typical dimensions included (rear opening dimension for insertion of an arc lamp 26 is included FIG. 7a).
  • the light rays After reflection off the elliptical surface, the light rays are directed to the aperture plane 24 as illustrated in FIGS. 2 and 5.
  • a measure of system performance is obtained by evaluating each ray at the aperture according to whether or not it lies within the aperture 25 of diameter d. Efficiency is then defined as the ratio of the number of rays which pass through the aperture 25 to the total number of rays generated by the arc lamp 26. Uniformity (or non- uniformity) in turn is defined as the energy distribution over the aperture or
  • FIG. 2 also illustrates an idealized version of illumination source 26 positioned on the optical axis A, a distance z ⁇ ff from the first ellipse focus 28.
  • the illumination source 26 is actually a simplified version of the arc 29 struck between the cathode 30 and anode 32 of the arc lamp 34 utilized (FIG. 7a) in the system reflector. It has been discovered that the envelope shape 40 surrounding the arc 29 will, in fact, have an effecct similar to negative decentration. In particular, it has been discovered that it is possible (in certain circumstances) to design the lamp envelope 40 to effectively provide the required negative decentration of the reflector without actual displacement of the reflector.
  • a calculation for estimating equivalent decentration caused by a real lamp envelope follows. If the lamp is in the shape of concentric spheres centered at the source, then light will be transmitted through without any deviation and there will be no source displacement. But if the envelope is ovoid shape, so that the center of curvature of the surfaces is displaced from the arc 29, then the image of the arc can be displaced from 11
  • the refraction of the source rays through the envelope 40 generates an image 46 of the source which is displaced from the source 26.
  • the image displacement is caused by the curved lamp envelope 40.
  • the displacement occurs in a given cross-section and the direction depends on the particular orientation of the cross-section.
  • the magnitude of this displacement D is determined as follows: From the law of sines, sin ⁇ __ ' sin( ⁇ - ⁇ -Q ) ( 5) R -r R
  • Equations (8) and (9) give the position and direction of the ray as it leaves the outer envelope 40. This may be used to project the ray backwards to the point where it intercepts the vertical axis. This is the position of the image of the source. By trigonometry the distance from the center of the two circles to the image may be computed: R (10)
  • the bulb diameter is 38 mm. Then the outer radius is 19 mm. If the thickness is 3 mm, then the inner radius r is 16 mm. Suppose the index of refraction of the envelope is 1.46 and the desired displacement D is 0.2 mm. Then the radius of curvature of the inner surface should be equal to
  • the source displacement caused by the lamp envelope may be used in lieu of an actual physical displacement.
  • the required decen- tration typically about 0.78 mm, is large enough to overshadow the image displacement caused by the lamp envelope, thus physical displacement is still required. In this latter case, the contribution to source displacement by the lamp envelope need not be taken into account.
  • the throw distance CTHRO is sufficiently long to overshadow bulb caused image displacement.
  • a computer program has been devised which responds to various input parameters, including tilt ⁇ and decentration DH, to provide an optimized reflector simulation such that light generated by the source (aperture lamp) is reflected to the aperture substantially uniform in energy distribution, the collection efficiency at the aperture being relatively high.
  • the computer program per se is not considered part of the present invention, some of the results of the computer simulation are set forth hereinafter to illustrate the multiplicity of additional reflector parameters which effect uniformity and efficiency and which should be considered in the reflector design.
  • Typical input parameters used in the program with respect to the ellipse see FIGS.
  • eccentricity c/a
  • throw distance CTHRO
  • cone angle o
  • ellipse diameter 2a
  • the previously noted decentration DH
  • tilt ⁇
  • aperture offset ZAP
  • source offset ZQFF
  • aperture size d
  • focus-to-focus separation distance between first ellipse focus 28 and second ellipse focus 31
  • Input parameters related to the source 26 include lamp diameter; and lamp illumination cutoff angle (XLU - XLU2) .
  • the illumination system was redesigned for various cone angles, throw distances, lamp sizes, 15
  • Typical ranges for these parameters for providing a highly efficient illumination system with high uniformity at the aperture are set forth in the right hand column. Ranges in performance factors are also set forth. The variations and parameters in the above ranges will provide an illumination system reflector which meets the requirements for liquid crystal light valve projector systems. The tilt and decentration concepts described hereinabove and the selection of the other reflector parameters can also be utilized to design reflectors for use in other projector systems, such as motion picture projectors.
  • FIG. 7a illustrates a more detailed view of the reflector design shown in FIG. 5, arc lamp 34 being centered on the optical axis A. Reflection of the rays 50, 52...88 emanating from arc 29 by reflector 18 is also illustrated.
  • FIG. 7b is an enlargement of the cathode region and shows the illumination arc 29 represented by a "ball of fire", or source 26, for computer simulation purposes and represents the maximum light brightness produced by the arc (the arc actually comprises light having a brightness gradient varying from the maximum adjacent cathode 30 to a lesser brightness adjacent anode 32).
  • the position of one of the rays 50 (angle ⁇ ) and its direction is also shown in FIG 7b.
  • the computer simulation assumes that the lamp illumination cutoff angles are XLU and XLU2, rays emanating from source 26 between these two angles being reflected from the inner surface of reflector 18. 17
  • the present invention thus provides a technique for improving the efficiency and uniformity characteris ⁇ tics of illumination system arc reflectors used in liquid crystal light valve projector systems and other types of projection systems.
  • the shape of the reflector is determined to provide maximum efficiency and uniformity given certain predetermined parameters, such as the physical configuration of the lamp and the throw distance required in the reflector system.
  • certain predetermined parameters such as the physical configuration of the lamp and the throw distance required in the reflector system.
  • the tilt of the ellipse axis from the optical axis, and the offset or decentration of the ellipse from the optical axis contributes significantly to increased efficiency and uniformities; the latter to a greater degree than the former.
  • Other parameters can be adjusted to obtain the combination of parameters which provide the optimum performance.
  • cone angle, lamp size and throw distance have been determined to significantly affect efficiency and uniformity, they are less likely to be variable since they are generally determined by other system constraints.
  • lamp envelope size can influence the decentration parameter and with a proper design for smaller throw distances, physical displacement of the ellipse surface to fulfill the decentration requirement may be eliminated.

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Business, Economics & Management (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • Educational Administration (AREA)
  • Educational Technology (AREA)
  • General Physics & Mathematics (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Projection Apparatus (AREA)
  • Aerials With Secondary Devices (AREA)

Abstract

Réflecteur de système d'illumination (18) offrant une énergie maximum à une ouverture (25) avec une uniformité élevée et à des rendements élevés, le réflecteur (18) étant particulièrement adapté pour être utilisé dans des systèmes de projection à relais optique à cristaux liquides. Une lampe à décharge (34) est utilisée avec un réflecteur elliptique (18), l'axe du réflecteur entre la focale primaire et secondaire étant incliné à un angle () par rapport à l'axe de la lampe. L'axe de l'ellipse (22) est déplacé par rapport à l'axe de la lampe dans une mesure prédéterminée (DH), la combinaison de l'inclinaison () et du déplacement (DH) étant efficace pour améliorer le rendement et l'uniformité de l'illumination à l'ouverture (25). D'autres paramètres du système, par exemple la distance de portée (CTHRO) et l'angle conique (alpha), peuvent également affecter l'uniformité et le rendement pour un modèle typique dans lequel les paramètres sont choisis de manière à fournir un système optimal. Il est également possible d'utiliser une simulation de programme informatique pour la sélection des paramètres. Il est démontré que le paramètre de déplacement vertical (DH) est apparenté aux dimensions de l'enveloppe de la lampe.
PCT/US1985/001254 1984-07-16 1985-07-01 Reflecteur de systeme d'illumination WO1986000685A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1019860700149A KR860700283A (ko) 1984-07-16 1985-07-01 조명 시스템 반사기

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US63128184A 1984-07-16 1984-07-16
US631,281 1984-07-16

Publications (1)

Publication Number Publication Date
WO1986000685A1 true WO1986000685A1 (fr) 1986-01-30

Family

ID=24530535

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1985/001254 WO1986000685A1 (fr) 1984-07-16 1985-07-01 Reflecteur de systeme d'illumination

Country Status (9)

Country Link
EP (1) EP0188541A1 (fr)
JP (1) JPS61502711A (fr)
KR (1) KR860700283A (fr)
AU (1) AU569404B2 (fr)
CA (1) CA1243644A (fr)
ES (1) ES8609665A1 (fr)
IL (1) IL75787A (fr)
NO (1) NO860827L (fr)
WO (1) WO1986000685A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2642209A1 (fr) * 1989-01-24 1990-07-27 Loire Electronique Dispositif d'eclairage pour ecran a cristaux liquides
US4950059A (en) * 1988-10-11 1990-08-21 General Electric Company Combination lamp and integrating sphere for efficiently coupling radiant energy from a gas discharge to a lightguide
USRE34492E (en) * 1988-10-11 1993-12-28 General Electric Company Combination lamp and integrating sphere for efficiently coupling radiant energy from a gas discharge to a lightguide
EP0713202A3 (fr) * 1994-10-25 1996-10-16 Klaus Buell Système de projection vidéo
US5640284A (en) * 1992-09-11 1997-06-17 Nikon Corporation Optical reflector, illumination optical system, light source system and illumination optical apparatus
WO2009060399A1 (fr) 2007-11-06 2009-05-14 Koninklijke Philips Electronics N.V. Système d'éclairage, lampe à décharge haute pression et système de projection d'images

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3689760A (en) * 1971-01-25 1972-09-05 Mattel Inc Efficient reflector for a projector
US4066887A (en) * 1976-10-27 1978-01-03 Maurice Levis Segmented sectional reflection for the projection of light beams and its method of production
DE3228575A1 (de) * 1982-07-30 1984-02-02 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 8000 München Baueinheit, bestehend aus ellipsoidreflektor und halogengluehlampe

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3720460A (en) * 1971-04-19 1973-03-13 Optical Radiation Corp Projection light source and optical system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3689760A (en) * 1971-01-25 1972-09-05 Mattel Inc Efficient reflector for a projector
US4066887A (en) * 1976-10-27 1978-01-03 Maurice Levis Segmented sectional reflection for the projection of light beams and its method of production
DE3228575A1 (de) * 1982-07-30 1984-02-02 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH, 8000 München Baueinheit, bestehend aus ellipsoidreflektor und halogengluehlampe

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4950059A (en) * 1988-10-11 1990-08-21 General Electric Company Combination lamp and integrating sphere for efficiently coupling radiant energy from a gas discharge to a lightguide
USRE34492E (en) * 1988-10-11 1993-12-28 General Electric Company Combination lamp and integrating sphere for efficiently coupling radiant energy from a gas discharge to a lightguide
FR2642209A1 (fr) * 1989-01-24 1990-07-27 Loire Electronique Dispositif d'eclairage pour ecran a cristaux liquides
US5640284A (en) * 1992-09-11 1997-06-17 Nikon Corporation Optical reflector, illumination optical system, light source system and illumination optical apparatus
EP0713202A3 (fr) * 1994-10-25 1996-10-16 Klaus Buell Système de projection vidéo
WO2009060399A1 (fr) 2007-11-06 2009-05-14 Koninklijke Philips Electronics N.V. Système d'éclairage, lampe à décharge haute pression et système de projection d'images

Also Published As

Publication number Publication date
IL75787A0 (en) 1985-11-29
KR860700283A (ko) 1986-08-01
EP0188541A1 (fr) 1986-07-30
IL75787A (en) 1992-11-15
ES8609665A1 (es) 1986-07-16
CA1243644A (fr) 1988-10-25
NO860827L (no) 1986-03-05
JPS61502711A (ja) 1986-11-20
AU4546085A (en) 1986-02-10
ES545193A0 (es) 1986-07-16
AU569404B2 (en) 1988-01-28

Similar Documents

Publication Publication Date Title
US4757431A (en) Off-axis application of concave spherical reflectors as condensing and collecting optics
JP3682300B2 (ja) 非結像光学的集中装置および照明システム
US5966250A (en) Method and light collection system for producing uniform arc image size
US5285318A (en) Illumination system having an aspherical lens
US2819649A (en) Reflecting condenser system for projectors
US6499862B1 (en) Spotlight with an adjustable angle of radiation and with an aspherical front lens
US5607229A (en) Illumination system including an asymmetrical projection reflector
US3529148A (en) Collector and method for producing a nearly uniform distribution of flux density on a target plane perpendicular to the optical axis
WO1992017733A1 (fr) Ensemble lampe et reflecteur
AU569404B2 (en) Illumination system reflector
JPH08511902A (ja) 反射器を備えるランプ
JP2870790B2 (ja) マイクロリーダプリンタの照明系
US3720460A (en) Projection light source and optical system
JP3792883B2 (ja) 照明装置およびこれを用いた投射型表示装置
EP3529654B1 (fr) Optique, luminaire et procédé de fabrication d'optique
US9638992B2 (en) Illumination optical system and image projection apparatus
JPH06508446A (ja) オーバーヘッドプロジェクター用集光レンズシステム
US4991072A (en) Radiation projector for producing a homogeneous flux
JPH03257444A (ja) マイクロリーダプリンタの照明系
US3266369A (en) Compound three-element lens assembly
US3215829A (en) Illumination device
JPS6227703B2 (fr)
JP2604471B2 (ja) 照明用光学系
JPH06102439A (ja) 集光照明装置
JPH03196134A (ja) 照明装置

Legal Events

Date Code Title Description
AK Designated states

Designated state(s): AU JP KR NO

AL Designated countries for regional patents

Designated state(s): CH DE FR GB IT NL SE

WWE Wipo information: entry into national phase

Ref document number: 1985903587

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1985903587

Country of ref document: EP

WWR Wipo information: refused in national office

Ref document number: 1985903587

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1985903587

Country of ref document: EP