WO1997022834A1 - Ensemble d'eclairage generant une source de lumiere polarisee - Google Patents

Ensemble d'eclairage generant une source de lumiere polarisee Download PDF

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Publication number
WO1997022834A1
WO1997022834A1 PCT/US1996/020306 US9620306W WO9722834A1 WO 1997022834 A1 WO1997022834 A1 WO 1997022834A1 US 9620306 W US9620306 W US 9620306W WO 9722834 A1 WO9722834 A1 WO 9722834A1
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WO
WIPO (PCT)
Prior art keywords
light
polarized
polarization state
microprisms
polarizing
Prior art date
Application number
PCT/US1996/020306
Other languages
English (en)
Inventor
Scott M. Zimmerman
Hefen Lin
Ivan Steiner
Haiji Yuan
Karl W. Beeson
Original Assignee
Alliedsignal 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 Alliedsignal Inc. filed Critical Alliedsignal Inc.
Publication of WO1997022834A1 publication Critical patent/WO1997022834A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • 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
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/14—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters for producing polarised light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0056—Means for improving the coupling-out of light from the light guide for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements

Definitions

  • This invention relates generally to an iUumination assembly that provides a polarized light source, and more particularly to a specifically designed backlight structure capable of providing a polarized collimated light source in two orthogonal viewing angles especially suitable for use with liquid crystal displays or any other appUcation that requires a polarized light source.
  • LCDs Liquid crystal displays
  • An exemplary LCD display is graphically illustrated in Fig. 1.
  • the overall display is made up of some type of backlighting apparatus, generically designated as 50, an input light polarizing means 52, a liquid crystal light modulator 54, an optional output light polarizing means 56 and a display means 58.
  • a liquid crystal light modulator is essentially a light valve which allows transmission of light in a first state and blocks transmission of light in a second state. Backlighting the LCD has become the most popular source of light in personal computer systems because ofthe improved contrast ratios and brightness .
  • LCDs require polarized light. Most light polarizers are inefficient. Nearly sixty percent ofthe light source is absorbed by the polarizers. This abso ⁇ tion limits the brightness ofthe display and contributes to the overall power inefficiency ofthe LCD.
  • the present invention is directed to an optical illumination system which provides either separately or in combination a non-diffuse or a substantially collimated polarized light source (hereinafter referred to as a spatially-directed polarized light source). Additionally, this invention is directed to any lighting application that requires a low profile spatially-directed polarized light source. In an LCD application, the invention may be used as a backlight that delivers a substantially collimated and polarized light source. The advantage is that minimal light is absorbed by the input polarizer since the light is already substantially polarized in the proper orientation, or even more preferably, an input polarizer is not used.
  • the optical illumination system comprises a light transmitting means having a generally planar top surface and bottom surface and opposing sides disposed between said top and bottom surfaces; means for directing light into said light transmitting means; a reflecting means optically coupled to said top surface for removing and redirecting the light from the light transmitting means; a polarizing means disposed between said top surface and said reflecting means for transmitting light polarized in a first polarization state out of said light transmitting means.
  • the remaining light, polarized in a second polarization state and not transmitted by said polarized means is recycled within said transmitting means and converted to the first polarization state or randomly polarized to allow light now polarized in the first polarization state to be transmitted by the polarizing means.
  • the cycles continues until substantially all ofthe input light is either transmitted by the polarizing means as a polarized light source or is eliminated from the optical system by various losses such as scattering or abso ⁇ tion.
  • a light source is positioned adjacent to a light accepting surface ofthe light transmitting means.
  • the light transmitting means may be any structure that transmits light via reflection, such as a light pipe, light wedge, waveguide or any other structure known to those skilled in the art.
  • the light transmitting means comprises a waveguide that accepts the light generated by the light source and transports the light via total intemal reflection (TIR).
  • TIR total intemal reflection
  • On one surface ofthe waveguide is a light polarizing means upon which is attached an array of microprisms.
  • Each microprism comprises a light input and a light output surface wherein the input surface is optically coupled to the light polarizing means.
  • the microprisms further comprise four sidewalls.
  • At least one ofthe four sidewalls is angled in such a way that light rays traveling through the waveguide are captured by the microprisms, redirected by the angled sidewall(s), reflect through the microprisms via TIR and emerge from the microprisms as a spatially-directed polarized light source.
  • a spatially-directed polarized light source is meant to include a substantially collimated polarized light source in a direction substantially pe ⁇ endicular to the light output surface or a polarized light source directed at an angle with respect to the normal ofthe light output surface.
  • an array of microlenses is operatively disposed adjacent to the light output surface ofthe microprisms.
  • the microlenses are formed with the proper curvature and positioned so that the light emanating from each microprism is dire ⁇ ed to at least one corresponding microlens.
  • the light transmits through the microlenses and emerges as a substantially more collimated polarized light source.
  • FIGURE 1 is a representative schematic of a prior art LCD in combination with a backlight
  • FIGURE 2 is a graph ofthe refection coefficient of p-polarized and s- polarized light
  • FIGURE 3 is a representation ofthe illumination system ofthe present invention.
  • FIGURE 4a is a preferred embodiment ofthe reflecting means in conjunction with the present invention.
  • FIGURE 4b is one embodiment of the polarizing film
  • FIGURE 4c is an alternate embodiment ofthe polarizing film
  • FIGURE 4d is a further embodiment ofthe polarizing film
  • FIGURE 5a is the preferred embodiment ofthe reflecting means in conjunction with the present invention
  • FIGURE 5b is a alternate view of the preferred reflecting means
  • FIGURE 6 is an elevation view ofthe preferred reflecting means in combination with an array of microlenses
  • FIGURE 7 is a specific embodiment of the polarizing film of FIG. 4b and; FIGURES 8a-b are graphs ofthe reflectance of p-polarized and s-polarized light ofthe polarizing film of FIG. 7.
  • LCD display for illustrative pu ⁇ oses; the invention, however, is applicable wherever a low profile spatially-directed polarized light source is required.
  • a polarizing backlight by forming a multilayer coating on the surface of a waveguide.
  • the coating should have alternating layers ofhigh and low index material.
  • the coating utilizes the optical property that when light strikes an interface at some incident angle other than normal incidence, p-polarized light (linearly polarized light which has the polarization vector in the plane containing the incident, reflected and transmitted rays) has a different reflection coefficient (Fresnel coefficient) than s-polarized light (linearly polarized light which has the polarization vector pe ⁇ endicular to the plane containing the incident, reflected and refracted rays).
  • TM c tan -1 1 ( ,— n2 s )
  • n 2 is the refractive index for the second material and ni is the refractive index for the first material (the material containing the incident ray).
  • ni is the refractive index for the first material (the material containing the incident ray).
  • Brewster's angle is approximately 61°. This is a typical angle for light traveling in a waveguide.
  • the polarizing effect for one TiO 2 /SiO 2 bilayer is approximately 5-
  • Stable cholesteric liquid crystal polymer films can be produced for example by using in-situ photopoiymerization of chiral liquid crystal diacrylates. Furthermore, cholesteric polymer films with a pitch gradient can be made to cover the whole spectrum of visible light and wide incident angles.
  • FIG. 3 An illumination system according to the present invention is shown in Fig. 3 It should be appreciated that all drawings are merely representations ofthe structure; the actual and relative dimensions will be different. It should also be appreciated that the elements shown in the drawings may not necessarily be contiguous, but rather merely adjacent.
  • the illumination system 12 contains a light source 14 and a light guide 16.
  • Light guide 16 may be any structure that transmits light via reflection, such as a light pipe, light wedge, waveguide or any other structure known to those skilled in the art.
  • Light guide 16 is transparent to light within the wavelength range from about 400 to about 700 nm.
  • the index of refraction ofthe light guide 16 may range from about 1.40 to about 1.65.
  • the most preferred index of refraction is from about 1.45 to about 1.60.
  • the light guide 16 may be made from any transparent solid material.
  • Preferred materials include transparent polymers, glass and fused silica. Desired characteristics of these materials include mechanical and optical stability at typical operation temperatures ofthe device. Most preferred materials are glass, acrylic, polycarbonate and polyester.
  • a polarizer film 44 that is constructed to transmit light of a first polarization state and reflect light of a second polarization state.
  • a reflector means 18 Optically coupled to polarizer film 44 is a reflector means 18 that has a light input surface that captures light transmitted by polarizer film 44 and one or more surfaces that redirect the light and outputs the light as a spatially- directed polarized light source.
  • Exemplary reflector means are disclosed in U.S. Patent No. 5,161,041, Japanese Publication Nos. 5-45505, 5-89827, 5-333334 and 5-127159.
  • reflector means is that disclosed in U.S. Patent Nos. 5,396,350 to Beeson et al. and 5,428,468 to Zimmerman et al.
  • FIG. 4a illustrates the invention in combination with preferred reflector means 18 for illustration pu ⁇ oses only, and are not intended to limit the scope ofthe invention.
  • reflecting means 18 comprises an array of microprisms 28 as disclosed in U.S. Patent No. 5,396,350.
  • Light rays reflect through light guide 16 via TIR and light rays of one polarization state transmit through polarizer film 44 and can enter microprisms 28 by way of light mput surfaces 30, reflect off sidewalls 33 and exit microprisms 28 through the light output surfaces 32 as a spatially-directed polarized light source.
  • Polarization conversion layer 48 can convert a first polarization state into a second polarization state and vice versa.
  • a polarization conversion layer is a birefnngent layer which can be designed to change: (a) a first linear polarization state into a second linear polarization state; (b) a first circular polarization state into a second circular polarization state; (c) a linear polarization state into a circular or elliptical polarization state; or (d) a circular or elliptical polarization state into a linear polarization state.
  • a polarization conversion layer 48 is a metallic mirror layer. Light striking a metallic mirror undergoes a phase shift of 180°. Because of this, a metallic mirror can convert right-circularly-polarized light into left-circularly- polarized light and vice versa.
  • Unpolarized light can be represented as containing equal proportions of two beams with different polarization states.
  • the two states can either be represented as two linear polarization states oriented at right angles to each other or the two states can be represented as right-circularly-polarized and left-circularly-polarized states.
  • polarization film 44 is designed to transmit one particular linear polarization state.
  • unpolarized light ray 50 is emitted by light source 14 and travels in light guide 16 via TIR.
  • the unpolarized light is illustrated as having two equal and pe ⁇ endicular linear polarizations.
  • polarizer film 44 is a multilayer stack of appropriate layers of different indexes of refraction ni and n 2 as shown in Fig 4b which is fabricated onto surface 17 Examples of materials that can make up film 44 are disclosed in U.
  • s-polarized ray 150 will be converted to circularly polarized ray 250 which is functionally equivalent to the ray being composed of equal parts of s-polarized and p-polarized light or to being randomly polarized.
  • Ray 250 is shown in Fig 4a as being composed of equal parts of p-polarized and s-polarized light.
  • Ray 250 can pass through polarization film 44 and again be split into its s-polarization component and p-polarization component where the s-polarization component will be reflected by polarization film 44 and the p-polarization component can be transmitted to reflecting means 18 and emerge from reflecting means 18 as spatially-directed polarized light.
  • polarization conversion layer 48 covering all or selected portions ofthe bottom surface of waveguide 16 is constructed from birefringent material to form a 1/4- wave layer.
  • s- polarized ray 150 will pass downward through layer 48, be reflected off the bottom surface of layer 48 by TIR since the bottom surface is in contact with air, pass through layer 48 a second time traveling in the upward direction and then return to light guide 16. Since the light ray experiences 1/2 wave retardation by passing twice through layer 48, s-polarized ray 150 will be converted into p-polarized light. The p-polarized light can then pass through polarization layer 44 and reflecting means 18 and emerge from reflecting means 18 as spatially-directed polarized light.
  • polarizing film 44 comprises of at least layer 45 of a circular polarizing material such as a cholesteric liquid crystal which transmits a first state of circular polarization (for example, right-circularly-polarized light) and reflects a second state of circular polarization (in this example, left-circularly-polarized light).
  • a circular polarizing material such as a cholesteric liquid crystal which transmits a first state of circular polarization (for example, right-circularly-polarized light) and reflects a second state of circular polarization (in this example, left-circularly-polarized light).
  • Light rays ofthe first circular polarization state can transmit through polarizer film 44 and can enter microprisms 28 of reflecting means 18 by way of light input surfaces 30, reflect off sidewalls 33 and exit microprisms 28 through the light output surfaces 32 as a spatially-directed circularly polarized light source.
  • polarization film 44 also comprises a 1/4-wave polarization conversion layer 46 in addition to circular polarizing layer 45.
  • Light of the first circular polarization state that is transmitted by layer 45 then passes through the 1/4-wave birefringent polarization conversion layer 46 which converts the circularly polarized light to linearly polarized light.
  • Linearly polarized light transmitted through 1/4- wave layer 46 can enter microprisms 28 by way of light input surfaces 30, reflect off sidewalls 33 and exit microprisms 28 through the light output surfaces 32 as spatially-directed linearly polarized light.
  • polarization conversion layer 46 is in optical contact with circular polarizing layer 45.
  • reflecting means 18 may be placed between circular polarizing layer 45 and polarization conversion layer 46 so that layers 45 and 46 are not in physical contact. Light ofthe second circular polarization state that is initially reflected off polarization film 44 will travel across the light guide 16 and interact with polarization conversion layer 48.
  • polarization conversion layer 48 is a birefringent 1/4 wave layer so that light ofthe second circular polarization state will pass downward through layer 48, reflect off the bottom surface of layer 48 by TIR, pass through layer 48 a second time traveling in the upward direction and then return to light guide 16 Since the light ray ofthe second circular polarization experiences 1/2 wave retardation by passing twice through layer 48, the light is converted to the first circular polarization state (right circularly polarized light in this example) and can now pass through polarization layer 44 and reflecting means 18 and emerge from reflecting means 18 as spatially-directed polarized light.
  • polarization conversion layer 48 is a metallic mirror. A metallic mirror changes the phase of reflected light by 180° relative to incident light.
  • a metallic mirror will change light of a second circular polarization state into light of a first circular polarization state.
  • light ofthe second circular polarization state left-circularly-polarized light in this example
  • the metallic mirror converts the light ofthe second circular polarization state to the first circular polarization state (right circularly polarized light in this example) and that light can now pass through polarization layer 44 and reflecting means 18 and emerge from reflecting means 18 as spatially-directed polarized light.
  • polarization conversion layer 48 is eliminated and polarizing film 44 is comprised of at least a layer consisting of alternating regions 47a and 47b of circularly polarizing materials such as various cholesteric liquid crystals.
  • Regions 47a are designed to transmit a first circular polarization state (for example, right-circularly-polarized light) and reflect a second polarization state (in this example, left-circularly- polarized light).
  • Light of a first circular polarization state that is transmitted by region 47a can enter of reflecting means 18 and emerge from reflecting means 18 as spatially-directed circularly polarized light.
  • Regions 47b are designed to work in the opposite manner as regions 47a.
  • regions 47b transmit a second circular polarization state and reflect a first circular polarization state.
  • Light of a second circular polarization state that is transmitted by region 47b can enter reflecting means 18 and emerge from reflecting means 18 as spatially-directed circularly polarized light.
  • light of a second polarization state that is reflected by a region 47a will travel through the light guide 16 by TIR and will eventually interact with a region 47b where it can be transmitted to reflecting means 18 and emerge from reflecting means 18 as spatially-directed circularly polarized light.
  • Light of a first polarization state that is reflected by a region 47b will travel through the light guide 16 by TIR and will eventually interact with a region 47a where it can be transmitted to reflecting means 18 and emerge from reflecting means 18 as spatially-directed circularly polarized light.
  • light exiting portions of reflecting means 18 in contact with regions 47a will have a first circular polarization state.
  • Light exiting portions of reflecting means 18 in contact with regions 47b will have a second circular polarization state.
  • polarization layer 44 must be comprised of polarization conversion regions 49a or polarization conversion regions 49b or both 49a and 49b in addition to circular polarization regions 47a and 47b
  • polarization layer 44 is comprised of circular polarization regions 47a and 47b and polarization conversion regions 49b which are birefringent 1/2-wave layers.
  • Light exiting reflecting means 18 in contact with circular polarization regions 47a will have a first polarization state.
  • Light transmitted through circular polarization regions 47b will have a second polarization state.
  • This second polarization state will be converted to a first polarization state by birefringent polarization conversion regions 49b and will emerge from reflecting means 18 in a first polarization state, the same polarization state as the portions of reflecting means 18 that are in contact with circular polarization regions 47a.
  • polarization layer 44 comprised of polarization regions 47a and 47b and 1/2 -wave birefringent polarization conversion regions 49a. The output of reflecting means 18 will then be entirely the second circular polarization state.
  • linear polarized light can be produced by having regions 47a designed to transmit a first circular polarization state, regions 47b designed to transmit a second circular polarization state, and polarization conversion regions 49a and 49b be 1/4-wave layers of birefringent material where the optical axis ofthe birefringent polarization conversion material in regions 49b is rotated 90° relative to the optical axis ofthe birefringent polarization conversion material in regions 49a.
  • the light transmitted from polarization conversion regions 49a and 49b will then be linearly polarized and in the same polarization state. This light will be transmitted to reflecting means 18 and emerge from reflecting means 18 as spatially-directed linearly polarized light.
  • birefringent polarization conversion regions 49a and 49b are in optical contact with circular polarization regions 47a and 47b and are located between circular polarizing regions 47a or 47b and reflecting means 18.
  • birefringent polarization conversion regions 49a and 49b are not in optical contact with circular polarization regions 47a or 47b.
  • reflecting means 18 is located between the circular polarization regions 47a and 47b and the birefringent polarization conversion regions 49a and 49b.
  • polarization conversion layer 48 located on the surface ofthe light guide opposite the polarizing layer 44.
  • polarization conversion layer 48 could be placed between light guide 16 and polarizing layer 44.
  • light guide 16 may itself be made from a birefringent material so that one state of polarized light could be converted to another state of polarized light or could be randomly polarized as it travels through light guide 16.
  • Figs. 5 and 5a illustrate an alternate embodiment of microprisms identified here as 90 and disclosed in U.S. Patent No. 5,428,468.
  • a second state of polarized light may be continuously recycled within light guide 16 to become randomly polarized to then allow the first state of polarized light to transmit through film 44.
  • This embodiment is useful for a single lamp embodiment and is also useful for an illumination system that comprises two opposing light sources 14 and 14 A. Each light source may act as a diffiiser element to randomly polarize reflected polarized light rays.
  • sidewalls 96 and 98 are tilted at angles ⁇ *, and ⁇ 2 , respectively, and sidewalls 97 and 99 form tilt angles ⁇ i, and ⁇ 2 .
  • Tilt angle ⁇ * may equal angle ⁇ 2 and angle ⁇ i may equal 02,but equality ofthe angles is not necessary.
  • the desired values of angle ⁇ range from about 15 to 50 degrees.
  • the desired values of tilt angle ⁇ range from about 0 degrees to about 25 degrees. More preferred values for tilt angle ⁇ range from about 2 degrees to about 20 degrees.
  • Light of one polarization state may be randomly polarized using the techniques discussed above.
  • one ofthe light sources 14 or 14A may be replaced with a reflecting means such as an eighth or quarter wave plate and a dilfijse or specular reflector.
  • the light ofthe second polarization state not transmitted by film 44 is changed to the first polarization state by the reflecting means or becomes randomly polarized and is recycled within the wave guide 16 so that light rays now polarized in the first polarization state will transmit through polarizing film 44 to again leave behind light ofthe second polarization state for recycling.
  • the cycles continues until substantially all ofthe input light is transmitted by film 44 or is lost from the optical system by scattering or abso ⁇ tion.
  • reflecting means 18 further comprises an array of microlenses 80 as shown in Fig. 6.
  • the microlenses 80 are disposed in close proximity to microprisms 28 and 90. If the microlenses 80 are fabricated by photopolymerization, they are preferably made from the same monomers as those previously disclosed for the microprisms and have a index of refraction equal to or substantially equal to the index of refraction ofthe microprisms. However, any transparent material may be used, as for example, those materials previously discussed. Preferably, for every microprism there exists at least one corresponding microlens 80 that aligns with the output surface of each microprism.
  • a spacer 82 separates the microlenses 80 and the microprisms.
  • the thickness of spacer 82 is optimized to cause light from the microprisms to be collimated by microlenses 80.
  • Spacer 82 may be made from any transparent material. Preferred materials include transparent polymers, glass and fused silica. Preferably spacer 82 has an index of refraction equal to or substantially equal to the index of refraction ofthe microprisms and the microlenses 80. Desired characteristics of these materials include mechanical and optical stability at typical operation temperatures ofthe device. Most preferred materials are glass, acrylic, polycarbonate and polyester.
  • Arrays of microprisms 28 and 90 and associated microlenses 80 can be manufactured by any number of techniques such as molding, including injection and compression molding, casting, including hot roller pressing casting, photopolymerization within a mold and photopolymerization processes which do not employ a mold.
  • a preferred manufacturing technique would be one that allows the reflecting means 18 which comprises an array of microprisms 28 or 90, an array of microlenses 80 and a spacer 82 to be manufactured as a single integrated unit.
  • An advantage of this technique would be the elimination of alignment errors between the array of microprisms and microlenses if the arrays were manufactured separately and then attached in the relationship described above.
  • a computer modeling program was used to calculate the polarization properties of a multilayer coating comprising alternating layers of titanium dioxide (TiO-*-) and silicon dioxide (SiO 2 ) on an acrylic substrate (refractive index 1 49).
  • the multilayer coating represented a Fabry-Perot type coating design.
  • the TiO 2 layers were assumed to have an index of refraction of 2.646; the Si ⁇ 2 layers were assumed to have an index of refraction of I 453
  • the thicknesses ofthe SiO 2 layers and the TiO 2 layers and the number of layers in the multilayer coating were varied to optimize the polarizing properties ofthe coating for 450 run, 550 nm and 650 nm light incident on the coating surface at angles ranging from 50° to 70° from normal
  • the design objective was to produce high s-polarized light reflectance and low p- polarized light reflectance for the stated wave lengths.
  • a seven (7) layer coating composed of three layers of TiO 2 and four layers of SiO 2 has very good polarization selection properties for light incident angles between 50° and 73°
  • Fig 7 illustrates the coating configuration
  • Figs. 8 and 8A graphically illustrate the computed reflectance of p-polarized and s-polarized light rays respectively

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Liquid Crystal (AREA)
  • Polarising Elements (AREA)

Abstract

Système d'éclairage optique comprenant un guide d'ondes (16) qui accepte la lumière générée par une source de lumière (14) et émet la lumière par réflexion interne totale. A une surface du guide d'ondes est fixé un groupement de microprismes (28) et un film polariseur (44) est placé entre le guide d'ondes (16) et les microprismes (28). Le film polariseur (44) émet la lumière polarisée sous forme d'un premier état de polarisation et envoie la lumière polarisée sous forme d'un second état de polarisation. La lumière réfléchie est transformée en lumière se présentant sous la forme du premier état de polarisation et permet l'émission de lumière par le film polariseur (44).
PCT/US1996/020306 1995-12-21 1996-12-20 Ensemble d'eclairage generant une source de lumiere polarisee WO1997022834A1 (fr)

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US57610895A 1995-12-21 1995-12-21
US08/576,108 1995-12-21

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GB2428129A (en) * 2005-07-08 2007-01-17 Sharp Kk A multiple-view directional display
EP1757962A3 (fr) * 2005-08-27 2007-03-28 Samsung Electronics Co., Ltd. Systeme d'eclairage pour dispositif d'affichage a ecran plat
WO2007070246A1 (fr) * 2005-12-13 2007-06-21 Rohm And Haas Denmark Finance A/S Film de polarisation tournant a reflexion interne totale
EP1850156A1 (fr) * 2006-04-27 2007-10-31 Samsung Electronics Co., Ltd. Unité de plaque de guidage lumineuse polarisante, unité de rétroéclairage et dispositif d'affichage l'utilisant
EP1953576A1 (fr) * 2007-02-01 2008-08-06 Samsung Electronics Co., Ltd. Plaque de guidage de lumière polarisée dotée d'une luminosité améliorée et son procédé de fabrication
US7796212B2 (en) 2007-04-12 2010-09-14 Samsung Electronics Co., Ltd. Liquid crystal display device having improved viewing angle and brightness
US7808582B2 (en) * 2006-05-11 2010-10-05 Samsung Electronics Co., Ltd. Illuminating apparatus wherein the plurality of polarization separating layers are disposed only to face the plurality of reflective patterns of the polarization light guide plate unit
US11385398B2 (en) * 2018-09-17 2022-07-12 Samsung Electronics Co., Ltd. Backlight unit and display apparatus having the same

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EP0597261A1 (fr) * 1992-10-09 1994-05-18 Asahi Glass Company Ltd. Dispositif d'éclairage et dispositif d'affichage à cristal liquide
EP0606939A1 (fr) * 1993-01-11 1994-07-20 Koninklijke Philips Electronics N.V. Système d'illumination et dispositif d'affichage comportant un tel système
US5396350A (en) * 1993-11-05 1995-03-07 Alliedsignal Inc. Backlighting apparatus employing an array of microprisms

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Publication number Priority date Publication date Assignee Title
EP0597261A1 (fr) * 1992-10-09 1994-05-18 Asahi Glass Company Ltd. Dispositif d'éclairage et dispositif d'affichage à cristal liquide
EP0606939A1 (fr) * 1993-01-11 1994-07-20 Koninklijke Philips Electronics N.V. Système d'illumination et dispositif d'affichage comportant un tel système
US5396350A (en) * 1993-11-05 1995-03-07 Alliedsignal Inc. Backlighting apparatus employing an array of microprisms

Cited By (10)

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Publication number Priority date Publication date Assignee Title
GB2428129A (en) * 2005-07-08 2007-01-17 Sharp Kk A multiple-view directional display
EP1757962A3 (fr) * 2005-08-27 2007-03-28 Samsung Electronics Co., Ltd. Systeme d'eclairage pour dispositif d'affichage a ecran plat
US7667788B2 (en) 2005-08-27 2010-02-23 Samsung Electronics Co., Ltd. Illumination system for flat panel display device
WO2007070246A1 (fr) * 2005-12-13 2007-06-21 Rohm And Haas Denmark Finance A/S Film de polarisation tournant a reflexion interne totale
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