TW201305480A - Remote phosphor converted LED - Google Patents

Abstract

The disclosure generally relates to broadband solid state illumination sources and image projectors that utilize a phosphor layer or material that is pumped or excited by light from one or more LEDs. The configuration is compact, efficient, and has especially low etendue.

Description

Remote phosphor-converted light-emitting diode

The present invention relates generally to light sources, and is particularly useful for solid state light sources incorporating light emitting diodes (LEDs) and phosphors. The invention is also related to related articles, systems and methods.

This application is related to the following U.S. patent applications incorporated by reference: "REMOTE PHOSPHOR POLARIZATION CONVERTER" (Attorney Docket No. 67422US002) and "OPTICAL STRUCTURE FOR REMOTE PHOSPHOR" (Attorney Docket No. 67421US002), both The application is filed on the same date as the case.

Solid state light sources that emit broadband light are known. In some cases, such light sources are fabricated by coating a yellow light emitting phosphor layer onto a blue LED. When light from the blue LED passes through the phosphor layer, some of the blue light is absorbed and a substantial portion of the absorbed energy acts as Stokes shifted light (usually yellow) at longer wavelengths in the visible spectrum. Re-emitted by the phosphor. The phosphor thickness is small enough that some of the blue LED light is always passed through the phosphor layer and combined with the yellow light from the phosphor to provide broadband output light with a white appearance.

Other LED pumped phosphor sources have also been proposed. In U.S. Patent 7,091,653 (Ouderkirk et al.), a light source is discussed in which ultraviolet (UV) light from an LED is reflected onto a phosphor layer by a remote reflector. The phosphor layer emits visible light (preferably white light) which is substantially transmitted by the remote reflector. So that when UV light travels from the LED to the remote reflector The LED light, the phosphor layer, and the long pass filter are disposed without passing the UV light through the phosphor layer.

The present invention generally relates to broadband solid state illumination sources and image projectors utilizing a phosphor layer or material that is pumped or energized by light from one or more LEDs. This configuration is compact, efficient and has a particularly low light spread. In one aspect, the present invention provides an illumination system including: a light emitting diode (LED) disposed on a substrate and configured to emit a first light beam in a first propagation direction such that The first beam passes through a collimating optics; a reflector disposed to reflect the first beam back through the collimating optics; a phosphor disposed adjacent to the LED and disposed on the substrate The visible light transparent region is disposed to intercept the first light beam; wherein a major portion of the first light beam is down-converted by the phosphor to become a second light beam propagating through one of the visible light transparent regions.

In another aspect, the present invention provides an image projector comprising: an illumination system; a polarization converter capable of converting a second beam into a third beam having a first polarization direction; An imager positioned to intercept the second beam of the first polarization direction; and projection optics. The illumination system includes: a light emitting diode (LED) disposed on a substrate and configured to emit a first light beam in a first propagation direction to pass the first light beam through a collimating optics; a reflector disposed to reflect the first beam back through the collimating optics; and a phosphor disposed adjacent to the LED on a visible light transparent region of the substrate, the phosphor The light body is positioned to intercept the first light beam. A major portion of the first beam is down-converted by the phosphor to become a second beam propagating through one of the visible regions of the visible light.

The above summary is not intended to describe each embodiment or every implementation of the invention. The following figures and detailed description more particularly exemplify illustrative embodiments.

Throughout the specification, reference is made to the drawings, in which like reference numerals

The figures are not necessarily drawn to scale. Similar numbers used in the figures refer to like components. It should be understood, however, that the use of a number to refer to a component in a given figure is not intended to limit the components in the other figures.

This application describes a broadband solid state illumination source utilizing a phosphor layer or material that is pumped or energized by light from one or more LEDs. The sources also include reflectors and collimating optics. In some cases, the reflector can be a bi-directional color reflector that reflects at least some of the LED light onto the phosphor layer. Light that exits the LED propagates within a collimation angle that enters the collimating optics, which increases the illumination area by subsequent reduction in the collimation angle of the light, thereby producing collimated light. The collimated light is reflected from the reflector and directed back through the collimating optics to the phosphor layer.

The present invention describes an LED that illuminates a phosphor at a distal end, wherein the LED is coupled to the collimating optic by a material having a relatively low refractive index, and the phosphorescent system is coupled by a material having a relatively high refractive index Connect to collimating optics. In a particular embodiment, LEDs and phosphors can use common collimating optics; however, separate collimating optics can also be used.

It is generally known that the light spread of a source is proportional to the square of the refractive index of the encapsulant surrounding the source. Because of the limited optical spread of many optical devices, it is often preferred to encapsulate a light source (e.g., an LED) in a low refractive index material such as air. In some optical devices, LEDs are used to excite wavelength converting materials such as phosphors or semiconductor wavelength converters. Many phosphor and semiconductor wavelength converters are more efficient when immersed in a package having a relatively high refractive index. Also, semiconductor wavelength converters can be expensive or contain hazardous materials, or both expensive and contain hazardous materials. Under such conditions, it may be desirable to immerse the wavelength converter in a medium having a higher refractive index to reduce the desired area. The disclosed apparatus has high optical efficiency in which the LED is in a low refractive index envelope and the phosphor is in a package having a higher refractive index while substantially not increasing the light spread of the system.

In some cases, the LED emits blue light (or UV light) and the reflector reflects the blue LED light onto the phosphor layer. One portion of the blue LED light can be combined with the longer wavelength light emitted by the phosphor to provide a broadband output beam, such as light having a white appearance. In some cases, the LEDs and/or phosphors can be disposed on the substrate, and the LEDs and phosphors are adhered or attached to the substrate in close proximity to one another. In a particular embodiment, the substrate can be a flexible substrate or a rigid substrate, and can include a transparent region on which the phosphor is deposited, as described elsewhere.

For the purposes of the description provided herein, both "color light" and "wavelength spectral light" are intended to mean light having a range of wavelengths that may be associated with a particular color (if visible to the human eye). The more general term "wavelength spectral light" refers to light of visible light and other wavelengths of light, including, for example, infrared light.

In this regard, "light emitting diode" or "LED" refers to emitting light (regardless of It is a diode of visible light, ultraviolet light or infrared light. "Light Emitting Diodes" or "LEDs" include discontinuously enclosed or encapsulated semiconductor devices sold as "LEDs" (known or super-radiated). "LED dies" are LEDs in their most basic form (i.e., in the form of individual components or wafers fabricated by semiconductor processing procedures).

In some cases, the LED can be a short wavelength LED capable of emitting UV photons. In general, the LED can be composed of any suitable material, such as an organic semiconductor or an inorganic semiconductor, including a Group IV element such as Si or Ge; such as InAs, AlAs, GaAs, InP, AlP, GaP, InSb, AlSb, GaSb, GaN , AlN, InN III-V compound and III-V compound alloy (such as AlGaInP and AlGaInN); such as ZnSe, CdSe, BeSe, MgSe, ZnTe, CdTe, BeTe, MgTe, ZnS, CdS, BeS, MgS An alloy of a Group II-VI compound and a Group II-VI compound, or an alloy of any of the compounds listed above.

In some cases, the LED can include one or more p-type and/or n-type semiconductor layers, can include one or more potential wells and/or one or more active layers of a quantum well, a buffer layer, a substrate layer, and a top Plate layer.

In some cases, the LED may include a CdMgZnSe alloy having the compounds ZnSe, CdSe, and MgSe as its three components. In some cases, one or more of Cd, Mg, and Zn (especially Mg) may be zero in the alloy and thus may not be in the alloy. For example, the LCD can further include a light conversion element (LCE) that can be used to convert light from one wavelength to another. In some cases, the LCE may include a Cd0.70Zn0.30Se quantum well capable of emitting red light or a Cd0.33Zn0.67Se capable of emitting green light. Quantum well. As another example, the LED and/or LCE may comprise an alloy of Cd, Zn, Se, and (as appropriate) Mg, in which case the alloy system may be represented by Cd(Mg)ZnSe. As another example, the LEDs and/or LCEs can include alloys of Cd, Mg, Se, and (as appropriate) Zn. In some cases, the thickness of the quantum well LCE is in the range of from about 1 nm to about 100 nm or from about 2 nm to about 35 nm.

In some cases, the semiconductor LED or LCE can be n-doped or p-doped, wherein doping can be achieved by any suitable method and by including any suitable dopant. In some cases, the LEDs and LCEs are from the same semiconductor family. In some cases, LEDs and LCEs come from two different semiconductor families. For example, in some cases, the LEDs are III-V semiconductor devices and the LCEs are II-VI semiconductor devices. In some cases, the LED includes an AlGaInN semiconductor alloy and the LCE includes a Cd(Mg)ZnSe semiconductor alloy. The LCE can generally be a phosphor, such as a phosphor particle in an organic binder, in an inorganic binder, or can be a semiconductor such as a ZnSe or ZnS compound.

The LCE can be disposed on or attached to the corresponding electroluminescent element by any suitable method, such as by an adhesive such as a hot melt adhesive, soldering, pressure, heat, or any combination of such methods. Light-emitting element. Examples of suitable hot melt adhesives include semicrystalline polyolefins, thermoplastic polyesters, and acrylic resins.

In a particular embodiment, the LED die can be formed from a combination of one or more Group III elements and one or more Group V elements (Group III-V semiconductors). Examples of suitable III-V semiconductor materials include nitrides such as gallium nitride and Such as phosphide indium phosphide. Other types of III-V materials as well as inorganic materials from other families of the periodic table can also be used. The component or wafer may include electrical contacts adapted to apply electrical power to supply energy to the device. Examples include wire bonding, tape automated bonding (TAB) or flip chip bonding. The individual layers and other functional components of the component or wafer are typically formed on a wafer scale, and the completed wafer can then be divided into individual components to yield a plurality of LED dies. LED dies can be configured for surface bonding, on-board wafers, or other known adhesive configurations. Some packaged LEDs are fabricated by forming a polymer encapsulant on the LED dies and associated reflective cups. For the purposes of this application, "LED" should also be considered to include organic light-emitting diodes commonly referred to as OLEDs.

In a particular embodiment, the phosphor can be a semiconductor such as a Group II-VI based system or a phosphor based on nitride, sulfide, selenide, and alumina, as described elsewhere. The phosphor may be a broadband emitter comprising one or more wavelength ranges covering the red, green or blue spectrum, or the phosphor may have a medium bandwidth covering, for example, the green portion of the spectrum, or the phosphor may be Narrowband transmitter. In some cases, the phosphor layer can be optically thin, meaning that the phosphor layer transmits 5% to 50% or more preferably 5% to 30% of the transmitted light. In some cases, the phosphor layer can include more than one type of phosphor such that the downconverted light includes more than one wavelength of light.

The present invention allows for light spread matching of LED sources that do not require encapsulation to achieve good efficiency. In some cases, the LED source can be encapsulated in a material having a refractive index between about 1.0 and about 1.2 or about 1.0 (ie, air). In a In some cases, the LED source may have a limit on the drive current density. In some cases, the phosphor can operate at high power densities, and in order to achieve higher efficiency of the pumping system, it is generally preferred to use an encapsulant to optically couple the phosphor to the primary optic.

In a particular embodiment, the area of the LED source is significantly larger than the area of the phosphor, and focusing optics can be used to increase the angular extent of illumination of the phosphor, which can be coupled to the focusing optics by a particular encapsulant The envelope has a higher refractive index than the material surrounding the LED. In some cases, the encapsulant can have a refractive index between about 1.2 and about 1.6 or between about 1.4 and about 1.5 or a refractive index of, for example, about 1.41.

In some cases, the etendue of the encapsulated phosphor can be matched to the unencapsulated LED, for example, by using a tapered rod to concentrate light from the LED source onto the phosphor. The tapered rod can be optically coupled to the collimating optics or can be separated from the collimating optics by an air gap. The phosphor can be optically coupled to the narrower substrate of the tapered rod by an encapsulating material such as polydimethyl oxyhydroxide. In some cases, a compound parabolic concentrator (CPC) can be used instead of a tapered rod. The CPC or tapered rod can be made of glass or plastic. The phosphor may be bonded to the tapered rod or CPC by a material such as polydimethyl oxyhydroxide having a refractive index of about 1.2 or higher, preferably 1.4 or higher.

1 shows a cross-sectional schematic view of an illumination system 100 in accordance with an aspect of the present invention. In FIG. 1, illumination system 100 includes a collection optics 105 that includes a first lens element 110 and a second lens element 120. The collection optics 105 includes a light input surface 114 and an optical axis 102 that is perpendicular to the light input surface 114. The first light source 140 is disposed on the light input table Light from face 114 exits surface 104. The light output region 170 is disposed in close proximity to the first light source 140 on the light exit surface 104. In some cases, one of the light output region 170 and the first light source 140 is disposed on the optical axis 102 and in close proximity to one another. In some cases, each of the light output region 170 and the first light source 140 is displaced from the optical axis 102 and is in close proximity to one another. However, the first source 140 and the light output region 170 are generally disposed in close proximity to the optical axis 102 such that the collimation angle of light emitted from the first source 140 and directed to the light output region 170 can be maintained. 1 shows a configuration of a first light source 140 that is slightly above the optical axis 102 and a light output region 170 disposed on the optical axis 102. In some cases, a second source (not shown) can be disposed at a location removed from the light exit surface 104 to direct the second light directly toward the light conversion region 170.

Any suitable substrate can be used for the light exiting surface 104 and can include a conductive layer or trace to carry electrical power to the LED. Preferably, the substrate also has a relatively high thermal conductivity and a relatively low thermal resistance to effectively carry heat away from the LED and/or phosphor layer in order to maintain a lower operating temperature of the LED and/or phosphor layer. To facilitate such lower operating temperatures, the substrate may comprise a suitable heat sink or be thermally coupled to a suitable heat sink, for example, a relatively thick copper layer, an aluminum layer or other suitable metal layer or other thermally conductive material (not shown) Show) layer. In some cases, the substrate can be or comprise a highly reflective surface such as a metal mirror, a metal mirror with a dielectric coating to enhance reflectivity, or a diffuse reflective surface such as a microporous polyester or titanium dioxide filled polymer, or such as 3M ^TM Vikuiti ^TM reflector enhanced specular reflector (ESR) multilayer optical film of the film. The substrate can also be or comprise any of the substrates discussed elsewhere herein.

The substrate can include a dielectric layer. Suitable dielectric layers include polyester, polycarbonate Esters, liquid crystal polymers and polyimine. Suitable polyimines include those available from DuPont under the trade name KAPTON, from Kaneka Texas corporation under the trade name APICAL, from SKC Kolon PI Inc. under the trade name SKC Kolon PI and under the trade name UPILEX And UPISEL are available from Ube Industries for their polyimine. Polyimines available under the trade names UPILEX S, UPILEX SN and UPISEL VT (both available from Ube Industries, Japan) are particularly advantageous in many applications. These polyimines are made from monomers such as biphenyl phthalic anhydride (BPDA) and p-phenylenediamine (PDA).

Additional design details of an exemplary flexible substrate suitable for use in the disclosed embodiments can be found in the commonly-owned U.S. Patent Application, entitled: "Flexible LED Device and Method of Making", filed on November 3, 2010. US Application No. 61/409,796 (Attorney Docket No. 66938US003); US Application No. 61/409,801, entitled "Flexible LED Device for Thermal Management and Method of Making", filed on November 3, 2010 (Attorney Docket No.) 67018US002); US Application 61/428034 (Attorney Docket No. 67006US002) entitled "Remote Phosphor LED Constructions", filed on December 29, 2010; and "LED Color Combiner", filed on December 29, 2010 US Application 61/428038 (Attorney Docket No. 67010US002).

In a particular embodiment, illumination system 100 further includes a reflector 132 disposed along optical axis 102 to face collection optics 105 such that first lens element 110 and second lens element 120 are in reflection Between the 132 and the light input surface 114. The reflector 132 can be disposed at an oblique angle φ to the optical axis and can be a bidirectional color reflector that is capable of reflecting the first color light 141 and transmitting all other color lights. Reflector 132 can alternatively be a broadband reflector, such as a wideband mirror.

In a particular embodiment, the collection optics 105 can be a light collimating optic 105 that collimates light emitted from the first source 140. Light collimating optics 105 can include a single lens optical collimator (not shown), a dual lens optical collimator (shown in the figures), a diffractive optical element (not shown), or a combination thereof. The dual lens optical collimator has a first lens element 110 that includes a first convex surface 112 disposed opposite the light input surface 114. The second lens element 120 includes a second surface 122 facing the first convex surface 112 and a third convex surface 124 opposite the second surface 122. The second surface 122 can be selected from a convex surface, a flat surface, and a concave surface.

The path of the first color light 141 from the first source 140 through the illumination system 100 can be tracked. The first color light 141 includes a first center ray 142a traveling in the first light propagation direction and a ray cone within the first input light collimation angle θ1i, the boundary of the ray cone being represented by the first boundary ray 144a, 146a. The first central ray 142a exits from the first source 140 in a direction generally parallel to the optical axis 102 and into the light input surface 114, through the first lens element 110, the second lens element 120, and from the reflector 132. The reflection is such that the first central reflected light 142b coincides with the optical axis 102, as shown in FIG. Each of the first boundary ray 144a, 146a exits in a direction substantially at a first input light collimation angle θ1i with the optical axis 102 to the light input surface 114, through the first lens element 110, the second Lens element 120, and self-reflecting The 132 is reflected such that the first boundary reflected rays 144b, 146b are substantially parallel to the optical axis 102, respectively, as re-entered the light collimating optics 105, as shown. As can be seen from FIG. 1, the light collimating optics 105 are used to collimate the first color light 141 that is transmitted from the first source 140 to the reflector 132.

Each of the first central ray 142a and the first boundary ray 144a, 146a is reflected from the reflector 132 and is substantially parallel to the optical axis 102 and, in some cases, concentrated on the optical axis 102 (eg, FIG. 1) The collimated light rays shown in the process travel back through the light collimating optics 105. In a particular embodiment as shown in FIG. 1, the collimated light converges to exit the illumination system 100 through the light output region 170 as a first output ray 148 having a first output collimation angle θ1o.

In a particular embodiment, the input collimation angle θ1i can be the same as the output collimation angle θ1o, and the exit optics associated with the first source 140 (not shown) can limit the input collimation angles to the following ranges. Angle: between about 10 degrees and about 80 degrees, or between about 10 degrees and about 70 degrees, or between about 10 degrees and about 60 degrees, or between about 10 degrees and about 50 degrees, or Between about 10 degrees and about 40 degrees, or between about 10 degrees and about 30 degrees, or less. In some cases, the light collimating optics 105 and the reflector 132 can be fabricated such that the output collimation angles θ1o can be the same and substantially equal to the input collimation angle θ1i. In a particular embodiment, each of the input collimation angles ranges from about 60 degrees to about 70 degrees, and the output collimation angle ranges from about 60 degrees to about 70 degrees.

2A shows a schematic diagram of a configuration near the light output region 170 of the illumination system 100 shown in FIG. 1 in accordance with an aspect of the present invention. Shown in Figure 2A Each of the elements 104-170 corresponds to the same numbered elements shown in Figure 1 that have been previously described. In FIG. 2A, light output region 170 includes phosphor 150 surrounded by encapsulant 155 disposed on visible transparent region 106 of light exit surface 104. The index of refraction of the encapsulant 155 is greater than the refractive index of the material surrounding the first source 140 as described elsewhere. The encapsulant 155 can be any of the encapsulating materials previously described, such as polydimethylox. In some cases, the encapsulant 155 can completely fill the gap between the light exit surface 104 and the light input surface 114. In some cases, the encapsulant 155 can alternatively be fabricated as a lens that includes a curved surface 156 (as shown in FIG. 2A) to focus the reflected light 142b, 144b, 146b that is incident on the light input surface 114 onto the phosphor 150. . After being intercepted by phosphor 150, a substantial portion of reflected light 142b, 144b, 146b is wavelength downconverted to exit illumination system 100 as output ray 148 having an output collimation angle θ1o.

2B shows a schematic diagram of the configuration of the vicinity of the light output region 170 of the illumination system 100 shown in FIG. 1 in accordance with an aspect of the present invention. Each of the elements 104-170 shown in Figure 2B corresponds to the same numbered elements shown in Figure 2A that have been previously described. In FIG. 2B, light output region 170 further includes a tapered rod 107 disposed adjacent to visible transparent region 106. The tapered rod 107 can be any of the tapered rods described elsewhere, and can have a reflective surface or a polished surface to achieve TIR from the surfaces. The tapered rod 107 is configured to deliver and further concentrate the output ray 148 such that the output ray 148 having the second output collimation angle θ2o is directed away from the illumination system 100. In some cases, the second output collimation angle θ2o may be the same as the input collimation angle θ1i.

2C shows the illumination system shown in FIG. 1 in accordance with an aspect of the present invention. Schematic diagram of the configuration near the light output area 170 of the system 100. Each of the elements 104-170 shown in Figure 2C corresponds to the same numbered elements shown in Figure 2A that have been previously described. In FIG. 2C, light output region 170 further includes a CPC 108 disposed adjacent to visible transparent region 106. The CPC 108 can be any of the CPCs described elsewhere, and can have reflective or polished surfaces to achieve TIR from such surfaces. The CPC 108 is configured to deliver and further concentrate the output light 148 such that the output light 148 having the third output collimation angle θ3o is directed away from the illumination system 100. In some cases, the third output collimation angle θ3o may be the same as the input collimation angle θ1i.

2D shows a schematic view of the vicinity of the light output region 170 of the illumination system 100 shown in FIG. 1 in accordance with an aspect of the present invention. Each of the elements 104-170 shown in Figure 2D corresponds to the same numbered elements shown in Figure 1 that have been previously described. In FIG. 2D, light output region 170 includes phosphor 150 surrounded by encapsulant 155 disposed on visible transparent region 106 of light exit surface 104. The index of refraction of the encapsulant 155 is greater than the refractive index of the material surrounding the first source 140 as described elsewhere. The encapsulant 155 can be any of the encapsulating materials previously described, such as polydimethylox. The encapsulant 155 is in the form of a tapered rod 107 disposed adjacent to the visible transparent region 106, and the phosphor 150 is disposed at the narrow end of the tapered rod 107. The tapered rod 107 can be any of the tapered rods described elsewhere, and can have a reflective surface or a polished surface to achieve TIR from the surfaces. The tapered rod 107 is configured to transport and further concentrate the reflected light 142b, 144b, 146b such that the reflected light 142b, 144b, 146b exits the illumination system 100 as the output light 148 having a fourth output collimation angle θ4o. In some cases, the fourth output collimation angle θ4o can It is the same as the input collimation angle θ1i.

2E shows a schematic diagram of the vicinity of the light output region 170 of the illumination system 100 shown in FIG. 1 in accordance with an aspect of the present invention. Each of the elements 104-170 shown in Figure 2E corresponds to the same numbered elements shown in Figure 1 that have been previously described. In FIG. 2E, light output region 170 includes phosphor 150 surrounded by encapsulant 155 disposed on visible transparent region 106 of light exit surface 104. The index of refraction of the encapsulant 155 is greater than the refractive index of the material surrounding the first source 140 as described elsewhere. The encapsulant 155 can be any of the encapsulating materials previously described, such as polydimethylox. The encapsulant 155 is in the form of a CPC 108 disposed adjacent to the visible transparent region 106, and the phosphor 150 is disposed at the narrow end of the CPC 108. The CPC 108 can be any of the CPCs described elsewhere, and can have reflective or polished surfaces to achieve TIR from such surfaces. The CPC 108 is configured to transport and further concentrate the reflected rays 142b, 144b, 146b such that the reflected rays 142b, 144b, 146b exit the illumination system 100 as output rays 148 having a fifth output collimation angle θ5o. In some cases, the fifth output collimation angle θ5o may be the same as the input collimation angle θ1i.

Figure 3 shows a schematic diagram of an image projector 1 in accordance with one aspect of the present invention. The image projector 1 includes a illuminator module 10 capable of emitting a partially collimated light output 24 to an optional homogenizing polarization converter module 30, in an optional uniformized polarization converter module 30, The partially collimated light output 24 is converted into uniformly polarized light 45 that is directed away from the optional uniformized polarization converter module 30 and into the image generator module 50. The image generator module 50 outputs image light 65, and the image light 65 enters the projection module 70 in the projection module 70. The image light 65 becomes the projected image light 80.

In one aspect, illuminator module 10 includes an input source that is input via light collimating optics 105 in illumination system 100, as described elsewhere. Illumination system 100 produces a light output that is emitted from illuminator module 10 as a partially collimated light output 24, as described elsewhere.

In one aspect, the input source is non-polarized and the partially collimated light output 24 is also non-polar. The partially collimated light output 24 can be a multi-color combined light that includes light of more than one wavelength spectrum. For the purposes of the description provided herein, both "color light" and "wavelength spectral light" are intended to mean light having a wavelength spectrum that is relevant to a particular color (if visible to the human eye). The more general term "wavelength spectral light" refers to light of visible light and other wavelengths of light, including, for example, infrared light.

According to one aspect, each input source comprises one or more light emitting diodes (LEDs). Various light sources can be used, such as lasers, laser diodes, organic LEDs (OLEDs), and non-solid state light sources (such as ultra high voltage (UHP) halogen or xenon lamps with appropriate concentrators or reflectors). Light sources, optical collimators, lenses, and optical integrators that can be used in the present invention are further described in, for example, the published U.S. Patent Application Serial No. US 2008/0285129, the disclosure of which is incorporated herein in its entirety. .

In one aspect, the optional uniformization polarization converter module 30 includes a polarization converter 40 that is capable of converting the non-polarized portion collimated light output 24 into uniformly polarized light 45. The optional uniformization polarization converter module 30 can further include a single array of lenses 42, such as the optional single-body FEA of the lens described elsewhere, which can be homogenized as uniformly polarized light 45 and can be selectively homogenized. Polarization conversion The partially modular combination of the color modules 24 outputs a color light output 24 and improves the uniformity of the light output. A representative configuration of an optional FEA associated with the optional homogenizing polarization converter module 30 is described, for example, in the following patent: U.S. Patent No. 61, entitled "FLY EYE INTEGRATOR POLARIZATION CONVERTER" in the same application. /346183 (Attorney Docket No. 66247US002, filed May 19, 2010), U.S. Patent No. 61/346,190, entitled "POLARIZED PROJECTION ILLUMINATOR" (Attorney Docket No. 66249US002, filed on May 19, 2010), And U.S. Patent No. 61/346,193, entitled "COMPACT ILLUMINATOR" (Attorney Docket No. 66360US002, filed on May 19, 2010).

In one aspect, image generator module 50 includes a polarizing beam splitter (PBS) 56, representative imaging optics 52, 54 and a spatial light modulator 58 that cooperate to convert uniformly polarized light 45 Image light 65. Suitable spatial light modulators (i.e., image generators) have been previously described, for example, in U.S. Patent Nos. 7,362,507 (Duncan et al.), 7,529,029 (Duncan et al.), U.S. Publication No. 2008-0285129-A1 (Magarill et al.), and PCT Publication No. WO2007/016015 (Duncan et al.). In a particular embodiment, uniformly polarized light 45 is divergent light from each lens of the optional FEA. After passing through imaging optics 52, 54 and PBS 56, uniformly polarized light 45 becomes imaging light 60 that uniformly illuminates the spatial light modulator. In a particular embodiment, each of the diverging ray bundles from each of the lenses in the optional FEA illuminates a major portion of the spatial light modulator 58 such that the individual scatter beams collide with each other.

In one aspect, projection module 70 includes representative projection optics 72, 74, 76 that can be used to project image light 65 as projected light 80. Suitable projection optics 72, 74, 76 have been previously described and are well known to those skilled in the art.

The following is a list of embodiments of the invention.

Item 1 is an illumination system comprising: a light emitting diode (LED) disposed on a substrate and configured to emit a first light beam in a first propagation direction such that the first light beam passes through a Collimating optics; a reflector disposed to reflect the first beam back through the collimating optics; an encapsulated phosphor disposed adjacent to the LED in a visible light transparent region of the substrate The encapsulated phosphor is disposed to intercept the first light beam; wherein a major portion of the first light beam is down-converted by the encapsulated phosphor to become propagated through one of the visible light transparent regions Two beams.

Item 2 is the illumination system of item 1, wherein the phosphor comprises an encapsulated phosphor.

Item 3 is the illumination system of item 1, wherein the encapsulated phosphor comprises an encapsulant having a refractive index between about 1.2 and about 1.6.

Item 4 is the illumination system of item 2 or item 3, wherein the encapsulated phosphor comprises an encapsulation having a refractive index between about 1.4 and about 1.5.

Item 5 is the illumination system of item 1 to item 4, further comprising a low refractive index material between the LED and the collimating optic, the low refractive index material having a refraction between about 1.0 and about 1.2 rate.

Item 6 is the lighting system of item 5, wherein the low refractive index material is empty gas.

Item 7 is the illumination system of item 1 to item 6, wherein the first light beam comprises a first light ray propagating within one of the first alignment angles of the first propagation direction.

Item 8 is the illumination system of item 1 to item 7, wherein the second light beam comprises a second light ray propagating within a second collimation angle of one of the second propagation directions opposite the first propagation direction.

Item 9 is the illumination system of item 1 to item 8, further comprising a focusing optic disposed between the encapsulated phosphor and the collimating optic, the focusing optic capable of focusing the first beam.

Item 10 is the illumination system of item 9, wherein the focusing optical element comprises a tapered glass rod or a compound parabolic concentrator (CPC).

Item 11 is the illumination system of item 1 to item 10, wherein the phosphor comprises a polydimethyl sulfoxide encapsulation.

Item 12 is the illumination system of item 1 to item 11, wherein the collimating optics comprises an optical axis, and at least one of the LED or the encapsulated phosphor is disposed on the optical axis.

Item 13 is the lighting system of item 1 to item 12, wherein the reflector is a broadband reflector.

Item 14 is the illumination system of item 1 to item 13, further comprising a second LED disposed to directly emit a third beam toward the phosphor.

Item 15 is an image projector comprising: an illumination system comprising: a light emitting diode (LED) disposed on a substrate and configured to emit a first light beam in a first propagation direction thereby Passing the first beam through a collimating optic; a reflector disposed to reverse the first beam Shooting back through the collimating optics; a phosphor disposed adjacent to the LED on a visible light transparent region of the substrate, the phosphor being disposed to intercept the first beam; wherein the first beam The main portion is down-converted by the phosphor to become a second light beam propagating through one of the visible light transparent regions; a polarization converter capable of converting the second light beam into one having a first polarization direction a third beam; an imager positioned to intercept the second beam of the first polarization direction; and projection optics.

All numbers expressing feature sizes, quantities and physical properties used in the specification and claims are to be understood as being modified by the term "about" unless otherwise indicated. Accordingly, unless otherwise indicated, the numerical parameters set forth in the foregoing description and the appended claims are intended to be <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> </ RTI> dependent on the desired properties sought to be obtained by those skilled in the art using the teachings disclosed herein.

All of the references and publications cited herein are expressly incorporated herein by reference in their entirety in their entirety in their entirety, unless the same reference While a particular embodiment has been illustrated and described herein, it will be understood by those skilled in the art . This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that the invention be limited only

1‧‧‧Image projector

10‧‧‧ illuminator module

24‧‧‧Partial collimated light output

30‧‧‧Optional Uniform Polarization Converter Module

40‧‧‧Polarization converter

42‧‧‧Lens array of lenses

45‧‧‧Uniformly polarized light

50‧‧‧Image Generator Module

52‧‧‧ imaging optics

54‧‧‧ imaging optics

56‧‧‧Polarized Beam Splitter (PBS)

58‧‧‧Space light modulator

60‧‧‧ imaging light

65‧‧‧Image light

70‧‧‧Projection Module

72‧‧‧Projection optics

74‧‧‧Projection optics

76‧‧‧Projection optics

80‧‧‧Projected image light

100‧‧‧Lighting system

102‧‧‧ optical axis

104‧‧‧Light shot surface/component

105‧‧‧Light collecting optics / light collimating optics

106‧‧‧ visible transparent area

107‧‧‧Conical rod

108‧‧‧Composite parabolic concentrator (CPC)

110‧‧‧First lens element

112‧‧‧First convex surface

114‧‧‧Light input surface

120‧‧‧second lens element

122‧‧‧ second surface

124‧‧‧ Third convex surface

132‧‧‧ reflector

140‧‧‧First light source

141‧‧‧First color light

142a‧‧‧First Center Light

142b‧‧‧The first center reflects light

144a‧‧‧First boundary light

144b‧‧‧First boundary reflected light

146a‧‧‧First boundary light

146b‧‧‧First boundary reflected light

148‧‧‧ first output light

150‧‧‧phosphor

155‧‧‧Encapsulation

156‧‧‧Bend surface

170‧‧‧Light output area/component

Figure 1 shows a schematic cross-sectional view of the illumination system; Figures 2A to 2E show schematic representations of the configuration near the light output area of the illumination system Figure 3 and Figure 3 show a schematic of an image projector.

100‧‧‧Lighting system

102‧‧‧ optical axis

104‧‧‧Light shot surface/component

105‧‧‧Light collecting optics / light collimating optics

110‧‧‧First lens element

112‧‧‧First convex surface

114‧‧‧Light input surface

120‧‧‧second lens element

122‧‧‧ second surface

124‧‧‧ Third convex surface

132‧‧‧ reflector

140‧‧‧First light source

141‧‧‧First color light

142a‧‧‧First Center Light

142b‧‧‧The first center reflects light

144a‧‧‧First boundary light

144b‧‧‧First boundary reflected light

146a‧‧‧First boundary light

146b‧‧‧First boundary reflected light

148‧‧‧ first output light

170‧‧‧Light output area/component

Claims (15)

An illumination system comprising: a light emitting diode (LED) disposed on a substrate and configured to emit a first light beam in a first propagation direction to pass the first light beam through a collimating optics a device; a reflector disposed to reflect the first beam back through the collimating optics; a phosphor disposed adjacent to the LED and disposed on a visible light transparent region of the substrate, the phosphor Positioning to intercept the first beam; wherein a major portion of the first beam is down-converted by the phosphor to become a second beam propagating through one of the visible regions of the visible light. The illumination system of claim 1 wherein the phosphor comprises an encapsulated phosphor. The illumination system of claim 2, wherein the encapsulated phosphor comprises an encapsulant having a refractive index between about 1.2 and about 1.6. The illumination system of claim 2, wherein the encapsulated phosphor comprises an encapsulant having a refractive index between about 1.4 and about 1.5. The illumination system of claim 1, further comprising a low refractive index material between the LED and the collimating optic, the low refractive index material having a refractive index between about 1.0 and about 1.2. The illumination system of claim 5, wherein the low refractive index material is air. The illumination system of claim 1, wherein the first light beam comprises a first light ray propagating within a first collimation angle of the first propagation direction. The illumination system of claim 1, wherein the second light beam is included in the first a second ray propagating within one of the second directions of propagation opposite the second direction of propagation. The illumination system of claim 1, further comprising a focusing optical element disposed between the phosphor and the collimating optic, the focusing optical element capable of focusing the first beam. The illumination system of claim 9, wherein the focusing optical element comprises a tapered glass rod or a compound parabolic concentrator (CPC). The illumination system of claim 1, wherein the phosphor comprises a polydimethyl sulfonate encapsulant. The illumination system of claim 1, wherein the collimating optics comprises an optical axis, and at least one of the LEDs or the phosphor is disposed on the optical axis. The illumination system of claim 1, wherein the reflector is a broadband reflector. The illumination system of claim 1, further comprising a second LED disposed to directly emit a third beam toward the phosphor. An image projector comprising: an illumination system comprising: a light emitting diode (LED) disposed on a substrate and configured to emit a first light beam in a first propagation direction to cause the first a beam of light passes through a collimating optics; a reflector disposed to reflect the first beam back through the collimating optics; a phosphor adjacent the LED and disposed on one of the substrates a light-transparent region, the phosphor is disposed to intercept the first light beam; wherein a main portion of the first light beam is down-converted by the phosphor to become a second light beam propagating through one of the visible light transparent regions; a polarization converter capable of converting the second beam into a third beam having a first polarization direction; an imager positioned to intercept the second beam in the first polarization direction; Projection optics.