Abstract:
This invention is related to LED Light Extraction for optoelectronic applications. More particularly the invention relates to (Al, Ga, In)N combined with optimized optics and phosphor layer for highly efficient (Al, Ga, In)N based light emitting diodes applications, and its fabrication method. A further extension is the general combination of a shaped high refractive index light extraction material combined with a shaped optical element.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is related to the following co-pending and commonly-assigned applications: 
         [0002]    U.S. Utility application Ser. No. 10/581,940, filed on Jun. 7, 2006, by Tetsuo Fujii, Yan Gao, Evelyn. L. Hu, and Shuji Nakamura, entitled “HIGHLY EFFICIENT GALLIUM NITRIDE BASED LIGHT EMITTING DIODES VIA SURFACE ROUGHENING,” attorney&#39;s docket number 30794.108-US-WO (2004-063), which application claims the benefit under 35 U.S.C Section 365(c) of PCT Application Serial No. US2003/03921, filed on Dec. 9, 2003, by Tetsuo Fujii, Yan Gao, Evelyn L. Hu, and Shuji Nakamura, entitled “HIGHLY EFFICIENT GALLIUM NITRIDE BASED LIGHT EMITTING DIODES VIA SURFACE ROUGHENING,” attorney&#39;s docket number 30794.108-WO-01 (2004-063); 
         [0003]    U.S. Utility application Ser. No. 11/054,271, filed on Feb. 9, 2005, by Rajat Sharma, P. Morgan Pattison, John F. Kaeding, and Shuji Nakamura, entitled “SEMICONDUCTOR LIGHT EMITTING DEVICE,” attorney&#39;s docket number 30794.112-US-01 (2004-208); 
         [0004]    U.S. Utility application Ser. No. 11/175,761, filed on Jul. 6, 2005, by Akihiko Murai, Lee McCarthy, Umesh K. Mishra and Steven P. DenBaars, entitled “METHOD FOR WAFER BONDING (Al, In, Ga)N and Zn(S, Se) FOR OPTOELECTRONICS APPLICATIONS,” attorney&#39;s docket number 30794.116-US-U1 (2004-455), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/585,673, filed Jul. 6, 2004, by Akihiko Murai, Lee McCarthy, Umesh K. Mishra and Steven P. DenBaars, entitled “METHOD FOR WAFER BONDING (Al, In, Ga)N and Zn(S, Se) FOR OPTOELECTRONICS APPLICATIONS,” attorney&#39;s docket number 30794.116-US-P1 (2004-455-1); 
         [0005]    U.S. Utility application Ser. No. 11/067,957, filed Feb. 28, 2005, by Claude C. A. Weisbuch, Aurelien J. F. David, James S. Speck and Steven P. DenBaars, entitled “HORIZONTAL EMITTING, VERTICAL EMITTING, BEAM SHAPED, DISTRIBUTED FEEDBACK (DFB) LASERS BY GROWTH OVER A PATTERNED SUBSTRATE,” attorneys&#39; docket number 30794.121-US-01 (2005-144-1); 
         [0006]    U.S. Utility application Ser. No. 11/923,414, filed Oct. 24, 2007, by Claude C. A. Weisbuch, Aurelien J. F. David, James S. Speck and Steven P. DenBaars, entitled “SINGLE OR MULTI-COLOR HIGH EFFICIENCY LIGHT EMITTING DIODE (LED) BY GROWTH OVER A PATTERNED SUBSTRATE,” attorneys&#39; docket number 30794.122-US-C1 (2005-145-2), which application is a continuation of U.S. Pat. No. 7,291,864, issued Nov. 6, 2007, to Claude C. A. Weisbuch, Aurelien J. F. David, James S. Speck and Steven P. DenBaars, entitled “SINGLE OR MULTI-COLOR HIGH EFFICIENCY LIGHT EMITTING DIODE (LED) BY GROWTH OVER A PATTERNED SUBSTRATE,” attorneys&#39; docket number 30794.122-US-01 (2005-145-1); 
         [0007]    U.S. Utility application Ser. No. 11/067,956, filed Feb. 28, 2005, by Aurelien J. F. David, Claude C. A Weisbuch and Steven P. DenBaars, entitled “HIGH EFFICIENCY LIGHT EMITTING DIODE (LED) WITH OPTIMIZED PHOTONIC CRYSTAL EXTRACTOR,” attorneys&#39; docket number 30794.126-US-01 (2005-198-1); U.S. Utility application Ser. No. 11/403,624, filed Apr. 13, 2006, by James S. Speck, Troy J. Baker and Benjamin A. Haskell, entitled “WAFER SEPARATION TECHNIQUE FOR THE FABRICATION OF FREE-STANDING (AL, IN, GA)N WAFERS,” attorneys&#39; docket number 30794.131-US-U1 (2005-482-2), which application claims the benefit under 35U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/670,810, filed Apr. 13, 2005, by James S. Speck, Troy J. Baker and Benjamin A. Haskell, entitled “WAFER SEPARATION TECHNIQUE FOR THE FABRICATION OF FREE-STANDING (AL, IN, GA)N WAFERS,” attorneys&#39; docket number 30794.131-US-P1 (2005-482-1); 
         [0008]    U.S. Utility application Ser. No. 11/403,288, filed Apr. 13, 2006, by James S. Speck, Benjamin A. Haskell, P. Morgan Pattison and Troy J. Baker, entitled “ETCHING TECHNIQUE FOR THE FABRICATION OF THIN (AL, IN, GA)N LAYERS,” attorneys&#39; docket number 30794.132-US-U1 (2005-509-2), which application claims the benefit under 35U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/670,790, filed Apr. 13, 2005, by James S. Speck, Benjamin A. Haskell, P. Morgan Pattison and Troy J. Baker, entitled “ETCHING TECHNIQUE FOR THE FABRICATION OF THIN (AL, IN, GA)N LAYERS,” attorneys&#39; docket number 30794.132-US-P1 (2005-509-1); 
         [0009]    U.S. Utility application Ser. No. 11/454,691, filed on Jun. 16, 2006, by Akihiko Murai, Christina Ye Chen, Daniel B. Thompson, Lee S. McCarthy, Steven P. DenBaars, Shuji Nakamura, and Umesh K. Mishra, entitled “(Al,Ga,In)N AND ZnO DIRECT WAFER BONDING STRUCTURE FOR OPTOELECTRONIC APPLICATIONS AND ITS FABRICATION METHOD,” attorneys&#39; docket number 30794.134-US-U1 (2005-536-4), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/691,710, filed on Jun. 17, 2005, by Akihiko Murai, Christina Ye Chen, Lee S. McCarthy, Steven P. DenBaars, Shuji Nakamura, and Umesh K. Mishra, entitled “(Al, Ga, In)N AND ZnO DIRECT WAFER BONDING STRUCTURE FOR OPTOELECTRONIC APPLICATIONS, AND ITS FABRICATION METHOD,” attorneys&#39; docket number 30794.134-US-P1 (2005-536-1), U.S. Provisional Application Ser. No. 60/732,319, filed on Nov. 1, 2005, by Akihiko Murai, Christina Ye Chen, Daniel B. Thompson, Lee S. McCarthy, Steven P. DenBaars, Shuji Nakamura, and Umesh K. Mishra, entitled “(Al, Ga, In)N AND ZnO DIRECT WAFER BONDED STRUCTURE FOR OPTOELECTRONIC APPLICATIONS, AND ITS FABRICATION METHOD,” attorneys&#39; docket number 30794.134-US-P2 (2005-536-2), and U.S. Provisional Application Ser. No. 60/764,881, filed on Feb. 3, 2006, by Akihiko Murai, Christina Ye Chen, Daniel B. Thompson, Lee S. McCarthy, Steven P. DenBaars, Shuji Nakamura, and Umesh K. Mishra, entitled “(Al,Ga,In)N AND ZnO DIRECT WAFER BONDED STRUCTURE FOR OPTOELECTRONIC APPLICATIONS AND ITS FABRICATION METHOD,” attorneys&#39; docket number 30794.134-US-P3 (2005-536-3); 
         [0010]    U.S. Utility application Ser. No. 11/251,365 filed Oct. 14, 2005, by Frederic S. Diana, Aurelien J. F. David, Pierre M. Petroff, and Claude C. A. Weisbuch, entitled “PHOTONIC STRUCTURES FOR EFFICIENT LIGHT EXTRACTION AND CONVERSION IN MULTI-COLOR LIGHT EMITTING DEVICES,” attorneys&#39; docket number 30794.142-US-01 (2005-534-1); 
         [0011]    U.S. Utility application Ser. No. 11/633,148, filed Dec. 4, 2006, Claude C. A. Weisbuch and Shuji Nakamura, entitled “IMPROVED HORIZONTAL EMITTING, VERTICAL EMITTING, BEAM SHAPED, DISTRIBUTED FEEDBACK (DFB) LASERS FABRICATED BY GROWTH OVER A PATTERNED SUBSTRATE WITH MULTIPLE OVERGROWTH,” attorneys&#39; docket number 30794.143-US-U1 (2005-721-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/741,935, filed Dec. 2, 2005, Claude C. A. Weisbuch and Shuji Nakamura, entitled “IMPROVED HORIZONTAL EMITTING, VERTICAL EMITTING, BEAM SHAPED, DFB LASERS FABRICATED BY GROWTH OVER PATTERNED SUBSTRATE WITH MULTIPLE OVERGROWTH,” attorneys&#39; docket number 30794.143-US-P1 (2005-721-1); 
         [0012]    U.S. Utility application Ser. No. 11/593,268, filed on Nov. 6, 2006, by Steven P. DenBaars, Shuji Nakamura, Hisashi Masui, Natalie N. Fellows, and Akihiko Murai, entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHT EMITTING DIODE (LED),” attorneys&#39; docket number 30794.161-US-U1 (2006-271-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/734,040, filed on Nov. 4, 2005, by Steven P. DenBaars, Shuji Nakamura, Hisashi Masui, Natalie N. Fellows, and Akihiko Murai, entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHT EMITTING DIODE (LED),” attorneys&#39; docket number 30794.161-US-P1 (2006-271-1); 
         [0013]    U.S. Utility application Ser. No. 11/608,439, filed on Dec. 8, 2006, by Steven P. DenBaars, Shuji Nakamura and James S. Speck, entitled “HIGH EFFICIENCY LIGHT EMITTING DIODE (LED),” attorneys&#39; docket number 30794.164-US-U1 (2006-318-3), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/748,480, filed on Dec. 8, 2005, by Steven P. DenBaars, Shuji Nakamura and James S. Speck, entitled “HIGH EFFICIENCY LIGHT EMITTING DIODE (LED),” attorneys&#39; docket number 30794.164-US-P1 (2006-318-1), and U.S. Provisional Application Ser. No. 60/764,975, filed on Feb. 3, 2006, by Steven P. DenBaars, Shuji Nakamura and James S. Speck, entitled “HIGH EFFICIENCY LIGHT EMITTING DIODE (LED),” attorneys&#39; docket number 30794.164-US-P2 (2006-318-2); 
         [0014]    U.S. Utility application Ser. No. 11/676,999, filed on Feb. 20, 2007, by Hong Zhong, John F. Kaeding, Rajat Sharma, James S. Speck, Steven P. DenBaars and Shuji Nakamura, entitled “METHOD FOR GROWTH OF SEMIPOLAR (Al,In,Ga,B)N OPTOELECTRONIC DEVICES,” attorneys&#39; docket number 30794.173-US-U1 (2006-422-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Application Ser. No. 60/774,467, filed on Feb. 17, 2006, by Hong Zhong, John F. Kaeding, Rajat Sharma, James S. Speck, Steven P. DenBaars and Shuji Nakamura, entitled “METHOD FOR GROWTH OF SEMIPOLAR (Al,In,Ga,B)N OPTOELECTRONIC DEVICES,” attorneys&#39; docket number 30794.173-US-P1 (2006-422-1); 
         [0015]    U.S. Utility patent application Ser. No. ______, filed on Nov. 15, 2007, by Aurelien J. F. David, Claude C. A. Weisbuch and Steven P. DenBaars entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHT EMITTING DIODE (LED) THROUGH MULTIPLE EXTRACTORS,” attorney&#39;s docket number 30794. 191-US-U1 (2007-047-3), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/866,014, filed on Nov. 15, 2006, by Aurelien J. F. David, Claude C. A. Weisbuch and Steven P. DenBaars entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHT EMITTING DIODE (LED) THROUGH MULTIPLE EXTRACTORS,” attorney&#39;s docket number 30794. 191-US-P1 (2007-047-1), and U.S. Provisional Patent Application Ser. No. 60/883,977, filed on Jan. 8, 2007, by Aurelien J. F. David, Claude C. A. Weisbuch and Steven P. DenBaars entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHT EMITTING DIODE (LED) THROUGH MULTIPLE EXTRACTORS,” attorney&#39;s docket number 30794. 191-US-P2 (2007-047-2); 
         [0016]    U.S. Utility patent application Ser. No. ______, filed on Nov. 15, 2007, by Claude C. A. Weisbuch, James S. Speck and Steven P. DenBaars entitled “HIGH EFFICIENCY WHITE, SINGLE OR MULTI-COLOUR LED BY INDEX MATCHING STRUCTURES,” attorney&#39;s docket number 30794. 196-US-U1 (2007-114-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/866,026, filed on Nov. 15, 2006, by Claude C. A. Weisbuch, James S. Speck and Steven P. DenBaars entitled “HIGH EFFICIENCY WHITE, SINGLE OR MULTI-COLOUR LED BY INDEX MATCHING STRUCTURES,” attorney&#39;s docket number 30794.196-US-P1 (2007-114-1); 
         [0017]    U.S. Utility patent application Ser. No. ______, filed on same date herewith, by Aurelien J. F. David, Claude C. A. Weisbuch, Steven P. DenBaars and Stacia Keller, entitled “HIGH LIGHT EXTRACTION EFFICIENCY LIGHT EMITTING DIODE (LED) WITH EMITTERS WITHIN STRUCTURED MATERIALS,” attorney&#39;s docket number 30794.197-US-U1 (2007-113-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional patent application Ser. No. ______, filed on same date herewith, by Aurelien J. F. David, Claude C. A. Weisbuch, Steven P. DenBaars and Stacia Keller, entitled “HIGH LIGHT EXTRACTION EFFICIENCY LED WITH EMITTERS WITHIN STRUCTURED MATERIALS,” attorney&#39;s docket number 30794.197-US-P1 (2007-113-1); 
         [0018]    U.S. Utility patent application Ser. No. ______, filed on Nov. 15, 2007, by Evelyn L. Hu, Shuji Nakamura, Yong Seok Choi, Rajat Sharma and Chiou-Fu Wang, entitled “ION BEAM TREATMENT FOR THE STRUCTURAL INTEGRITY OF AIR-GAP III-NITRIDE DEVICES PRODUCED BY PHOTOELECTROCHEMICAL (PEC) ETCHING,” attorney&#39;s docket number 30794.201-US-U1 (2007-161-2), which application claims the benefit under 35 U.S. C Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/866,027, filed on Nov. 15, 2006, by Evelyn L. Hu, Shuji Nakamura, Yong Seok Choi, Rajat Sharma and Chiou-Fu Wang, entitled “ION BEAM TREATMENT FOR THE STRUCTURAL INTEGRITY OF AIR-GAP III-NITRIDE DEVICES PRODUCED BY PHOTOELECTROCHEMICAL (PEC) ETCHING,” attorney&#39;s docket number 30794.201-US-P1 (2007-161-1); 
         [0019]    U.S. Utility patent application Ser. No. ______, filed on Nov. 15, 2007, by Steven P. DenBaars, Shuji Nakamura and Hisashi Masui, entitled “HIGH LIGHT EXTRACTION EFFICIENCY SPHERE LED,” attorney&#39;s docket number 30794.204-US-U1 (2007-271-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/866,025, filed on Nov. 15, 2006, by Steven P. DenBaars, Shuji Nakamura and Hisashi Masui, entitled “HIGH LIGHT EXTRACTION EFFICIENCY SPHERE LED,” attorney&#39;s docket number 30794.204-US-P1 (2007-271-1); 
         [0020]    U.S. Utility patent application Ser. No. ______, filed on Nov. 15, 2007, by Shuji Nakamura and Steven P. DenBaars, entitled “STANDING TRANSPARENT MIRROR-LESS (STML) LIGHT EMITTING DIODE,” attorney&#39;s docket number 30794.205-US-U1 (2007-272-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/866,017, filed on Nov. 15, 2006, by Shuji Nakamura and Steven P. DenBaars, entitled “STANDING TRANSPARENT MIRROR-LESS (STML) LIGHT EMITTING DIODE,” attorney&#39;s docket number 30794.205-US-P1 (2007-272-1); and 
         [0021]    U.S. Utility patent application Ser. No. ______, filed on Nov. 15, 2007, by Steven P. DenBaars, Shuji Nakamura and James S. Speck, entitled “TRANSPARENT MIRROR-LESS (TML) LIGHT EMITTING DIODE,” attorney&#39;s docket number 30794.206-US-UL (2007-273-2), which application claims the benefit under 35 U.S.C Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/866,023, filed on Nov. 15, 2006, by Steven P. DenBaars, Shuji Nakamura and James S. Speck, entitled “TRANSPARENT MIRROR-LESS (TML) LIGHT EMITTING DIODE,” attorney&#39;s docket number 30794.206-US-P1 (2007-273-1); all of which applications are incorporated by reference herein. 
         [0022]    This application claims the benefit under 35 U.S.C. Section 119(e) of co-pending and commonly-assigned U.S. Provisional Patent Application Ser. No. 60/866,024, filed on Nov. 15, 2006, by Natalie N. Fellows, Steven P. DenBaars and Shuji Nakamura, entitled “TEXTURED PHOSPHOR CONVERSION LAYER LIGHT EMITTING DIODE,” attorney&#39;s docket number 30794.203-US-P1 (2007-270-1); which application is incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0023]    1. Field of the Invention 
         [0024]    This invention is related to LED Light Extraction and white LED with high luminous efficacy for optoelectronic applications, and, more specifically, relates to a textured phosphor conversion layer LED. 
         [0025]    2. Description of the Related Art 
         [0026]    (Note: This application references a number of different publications as indicated throughout the specification. A list of these different publications can be found below in the section entitled “References.” Each of these publications is incorporated by reference herein.) 
         [0027]    In conventional white LEDs, the phosphor conversion layer is typically placed directly on top of the blue GaN chip. The surface is usually smooth and conformal to the surface of the GaN chip. The blue photons from the GaN chip are down converted into photons of lower energy (Yellow, Green, and Red) in the phosphor conversion layer. A large fraction of these photons are internal reflected in the phosphor conversion layer and directed back toward the chip where they are reabsorbed. This results in a decrease in overall luminous efficiency. 
         [0028]    Previous applications of the phosphor conversion layer are limited to placing a gel or other liquid form of material onto the chip, and allowing the phosphor to cure. This non-uniform and typically smooth application of the phosphor does not take into account several factors that can be used to increase the efficiency of the LED. 
       SUMMARY OF THE INVENTION 
       [0029]    The present invention describes an (Al, Ga, In)N and light emitting diode (LED) combined with a textured, or shaped, phosphor conversion in which the multi directions of light can be extracted from the surfaces of the chip and phosphor layer before subsequently being extracted to air. The present invention combines the high light extraction efficiency LED chip with shaped (textured) phosphor layers to increase the total luminous efficacy of the device. As a result, this combined structure extracts more light out of the white LED. 
         [0030]    The present invention minimizes the internal reflection of the phosphor layer by preferential patterning the emitting surface to direct more light away from the absorbing chip structure. In order to minimize the internal reflection of the LED light further, transparent electrode such as Indium Tin Oxide (ITO) or Zinc Oxide (ZnO), or the surface roughening of AlInGaN by patterning or anisotropically etching, or the roughening of ITO and ZnO, or the roughening of epoxy and glass or the roughening of the phosphor layer, are used. The present invention furthermore combines the high light extraction efficiency LED chip with shaped (textured) phosphor layers to increase the total luminous efficacy of the device. As a result, this combined structure extracts more light out of the LED. 
         [0031]    More particularly the invention relates to (Al, Ga, In)N LEDs and light extraction structure combined with phosphors and optimized optics for highly efficient (Al, Ga, In)N based light emitting diodes applications, and its fabrication method. Present invention describes a white high efficient LED created by maximizing extraction from the photon conversion layer. In the present invention it has been shown that roughening the surface of a phosphor layer increases the luminous efficacy of a white LED. In order to roughen the phosphor layer the phosphor is first prepared in a resin mixture. It is then poured directly onto an aluminum oxide 120-grit square piece of sandpaper (120 abrasive particles per inch). The optic used for the remote phosphor layer is then placed on top of the phosphor. This serves to flatten the phosphor on the sandpaper so that a thin uniform layer is produced. These items are then heated under the curing conditions for the resin. 
         [0032]    A further extension is the general combination of a shaped high refractive index light extraction material with transparent conducting electrodes, textured phosphor conversion layers and shaped optical elements. The overall effect is to achieve a device with superior luminous efficacy and a high output power. 
         [0033]    A Light Emitting Diode (LED) in accordance with the present invention comprises an LED chip, emitting light at a first wavelength region, an encapsulation layer, coupled to the LED chip, wherein the encapsulation layer is transparent at the first wavelength region, and a phosphor layer, coupled to the encapsulation layer and distant from the LED chip, the phosphor layer converting the light emitted by the LED chip in the first wavelength region to light in at least a second wavelength region, wherein at least a portion of a surface of the phosphor layer is textured. 
         [0034]    Such an LED further optionally comprises the LED being made from a material selected from the group comprising (Al, Ga, In)N material system, the (Al, Ga, In)As material system, the (Al, Ga, In)P material system, the (Al, Ga, In) AsPNSb material system, and the ZnGeN2 and ZnSnGeN2 material systems, the textured phosphor layer having a cone shape, the encapsulation layer comprising epoxy, glass, air, and other materials that are transparent at the emission wavelength, at least a portion of a second surface of the phosphor layer being textured, the transparent electrode comprising a material selected from a group comprising ITO, ZnO, and a thin metal, the LED chip further comprising a current spreading layer, a textured sapphire substrate being used for the LED chip to increase the light transmission from the LED chip, a backside of the textured sapphire substrate being textured, the LED being molded into an inverted cone shape, light being extracted from the LED in a direction normal to the emitting surface of the LED chip, a mirror, and the mirror being designed such that light striking the mirror is reflected away from the LED chip. 
         [0035]    Another LED in accordance with the present invention comprises an LED chip, emitting light at a first wavelength region and having a first refractive index, an encapsulation layer, coupled to the LED chip, wherein the encapsulation layer is transparent at the first wavelength region and having a second refractive index less than the first refractive index, wherein the second refractive index is greater than 1, and a phosphor layer, coupled to the encapsulation layer and distant from the LED chip, the phosphor layer converting light emitted in the first wavelength region to light in at least a second wavelength region, wherein at least a portion of a surface of the phosphor layer farthest from the LED chip is not normal to the light emitted from the LED chip. 
         [0036]    Such an LED further optionally comprises the LED being made from a material selected from the group comprising (Al, Ga, In)N material system, the (Al, Ga, In)As material system, the (Al, Ga, In)P material system, the (Al, Ga, In) AsPNSb material system, and the ZnGeN2 and ZnSnGeN2 material systems, the phosphor layer having a cone shape, at least a portion of a second surface of the phosphor layer closer to the LED chip also being textured, the encapsulation layer comprising a material selected from a group comprising ITO, ZnO, and a thin metal, the LED chip further comprising a current spreading layer, and the encapsulation layer comprising epoxy, glass, and other materials that are transparent at the emission wavelength. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    Referring now to the drawings in which like reference numbers represent corresponding parts throughout: 
           [0038]      FIG. 1  illustrates the white LED structure of the present invention; 
           [0039]      FIG. 2  illustrates the luminous efficacy of the white LEDs shown in  FIG. 1 ; 
           [0040]      FIG. 3  illustrates the white LED structure of the present invention with a roughened phosphor layer on both sides of the interface between the epoxy and the phosphor; 
           [0041]      FIG. 4  illustrates the one side roughened phosphor layer of the present invention placed directly on the LED chip; 
           [0042]      FIG. 4  illustrates the one side roughened phosphor layer of the present invention placed directly on the LED chip; 
           [0043]      FIG. 5  illustrates the dual-sided roughened phosphor layer of the present invention placed directly on the LED chip; 
           [0044]      FIG. 6  illustrates the one side roughened phosphor layer of the present invention placed inside of the epoxy molding; 
           [0045]      FIGS. 7 and 8  illustrate the dual-sided roughened phosphor layer of the present invention placed inside of the epoxy molding; 
           [0046]      FIGS. 9 and 10  illustrate an LED structure of the present invention using thick epoxy layers; 
           [0047]      FIG. 11  illustrates a cross-sectional view of an LED of the present invention molded into a spherical shape; 
           [0048]      FIG. 12  illustrates the LED chip of the present invention with a roughened transparent oxide conductor layer; 
           [0049]      FIG. 13  illustrates a current spreading layer in accordance with the present invention; 
           [0050]      FIG. 14  illustrates a mirror placed outside of the spherical LED of the present invention; 
           [0051]      FIG. 15  illustrates another embodiment of the present invention; 
           [0052]      FIG. 16  illustrates an internal mirror in accordance with the present invention; 
           [0053]      FIG. 17  illustrates a emission schema in a direction normal to the LED emissions in accordance with the present invention; 
           [0054]      FIG. 18  illustrates an alternative embodiment of the emission schema shown in  FIG. 17 ; and 
           [0055]      FIG. 19  illustrates another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0056]    In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
         [0057]    Overview 
         [0058]    The present invention describes the high efficient LEDs which use the phosphor to change the emission color of the LEDs.  FIG. 1  shows the structure of the white LEDs which utilize the phosphor to get the white emission color. The phosphor layer is located near the surface of the inverted cone shape epoxy molding. When the surface of the phosphor layer is roughened, the luminous efficacy of the white LEDs is increased as shown in  FIG. 2  in comparison with the white LEDs with a flat surface of the phosphor layer. The surface roughening improves the light extraction efficiency by reducing the reflection of the light at the interface between the phosphor layer and the air. 
         [0059]    The present invention also includes an (Al, Ga, In)N and light emitting diode (LED) in which the multiple directions of light can be extracted from the surfaces of the chip before then entering the shaped plastic optical element and subsequently extracted to air after exciting the phosphor. In particular the (Al, Ga, In)N and transparent contact layers (ITO or ZnO) is combined with a shaped lens in which most light entering lens lies within the critical angle and is extracted. The present invention also includes a high efficient LED by minimizing the re-absorption of LED emission without any intentional mirrors attached to LED chip. The conventional LEDs have used a high reflective mirror in order to increase the front emission by reflecting the LED light forward direction. See  FIGS. 1-3 . However, this reflected emission is always partly re-absorbed by the emission layer or active layer of the LED. Then, the efficiency or the output power of LED was decreased. See  FIGS. 1-3 . The present invention reduces reflection from the phosphor layer, plastic encapsulant surface, reflection from the ITO or ZnO surface, reduces reflection from the GaN by roughening, patterning or anisotropically etched surface(microcones), and minimizes light re-absorption by the emitting layer (active layer) without any intentional mirrors attached to LED chip, enables uniform light emitting from active layer to both sides of front and back sides. The present invention furthermore combines the high light extraction efficiency LED chip with shaped (textured) phosphor layers to increase the total luminous efficacy of the device. As a result, this combined structure extracts more light out of the LED. See  FIGS. 4-19 . 
       DETAILED DESCRIPTION 
       [0060]    In all of  FIGS. 1-19 , the details of the LED structure are not shown. Only the emitting layer (usually AlInGaN MQW), p-type GaN, n—GaN, sapphire substrate are shown. In the complete LED structure, there can be other layers such as p—AlGaN electron blocking layer, InGaN/GaN super lattices and others. Here, the most important parts are surface of the LED chip because the light extraction efficiency is determined mainly by the surface layer or condition of the epitaxial wafers. So, only some parts (the surface layers) of the LED chip are shown in all of the figures. 
         [0061]      FIG. 1  illustrates a white LED structure of the present invention. 
         [0062]    Light Emitting Diode (LED)  100  comprises LED chip  102  and a phosphor layer  104 . The phosphor layer  104  is excited by the blue light from the LED chip  102  and converts the blue light, in the first wavelength region, to light in a second wavelength region. The phosphor layer is located near the surface of the inverted cone shape epoxy molding  106  to improve the conversion efficiency of the phosphor layer  104 . 
         [0063]    The surface  108  of the phosphor layer is roughened to increase the converted light extraction  110  from the phosphor layer  104 . At least a portion of surface  108 , rather than being completely planar, is roughened, textured, patterned, or otherwise made not normal to the light  112  emitted from the LED chip  102  so that reflection of light  112  is reduced. This irregular surface  108  may be generated through additional processing of phosphor layer  104 , or may occur as the phosphor layer  104  is applied to LED  100 , without departing from the scope of the present invention. 
         [0064]    Although shown as a pyramid-like shape, the surface  108  can take any shape, so long as the shape of surface  108  reduces reflections of light  112  or increases the efficiency of conversion performed by phosphor layer  104 . Some of the blue light  112  is reflected at the interface between the epoxy  106  and the phosphor layer  104  due to the flat surface of the back side of the phosphor layer  104 . 
         [0065]    LED chip  102  typically comprises a sapphire wafer  114  and a ITT-nitride LED active layer  116 . The active layer  116  typically emits blue light  112 , which excites phosphor layer  104  into producing yellow light  110 . To increase the efficiency of LED  100 , a zinc oxide (ZnO) layer  106  can be formed with a refractive index that is between that of the LED chip  102  and that of air, and for ZnO layer  106  the refractive index n is 2.1. Further, layer  106  can comprise ZnO, ITO, a thin metal, as well as an epoxy or some combination of these and other materials. Any material can be used for layer  106 , so long as layer  106  is transmissive at the wavelengths being emitted by LED chip  102 . The blue light  112  and the yellow emissions  110  both emit from LED  100  to form white light that emits from the surface  118  of LED  100 . 
         [0066]      FIG. 2  illustrates the luminous efficacy of the white LEDs of the present invention that are illustrated in  FIG. 1 . 
         [0067]    Graph  200  shows a chart of current on the x-axis and lumens per watt on the y-axis. Line  202  shows an un-roughened phosphor layer  104 , e.g., one with a flat upper surface rather than a roughened surface  108 . As the surface  108  of the phosphor layer  104  is roughened, the luminous efficacy of the white LEDs is increased, as shown in graphs  204  and  206 , due to the improvement of the light extraction efficiency from the phosphor layer  104 . 
         [0068]      FIG. 3  illustrates the white LED structure with a roughened phosphor layer on both sides of the interface between the epoxy and the phosphor layer. 
         [0069]    As in  FIG. 1 , the upper surface  108  is roughened or textured, and now, in LED  300 , at least a portion of the lower surface  302  of the phosphor layer  104  is also roughened or textured or otherwise made non-normal to the incident light  112 . This allows for less reflection of blue light  112 , and thus improves the efficiency of LED  300 , because now the light  112  that was previously reflected is now emitted from the upper surface  108  of LED  300  or excites phosphor layer  104 . The interface between the epoxy  106  and the phosphor layer  104 , resulting in surface  302 , is roughened to improve the conversion efficiency of the phosphor layer  104  by reducing the reflection of the blue light  112  that is shown in  FIG. 1 . The surface  302  can be created by texturing or roughening the surface of epoxy molding layer  106 , or by using other methods to generate a textured or roughened surface  302 . Further, the surface  302  may not be uniformly roughened or textured; the texture may take on different characteristics depending on where the LED chip  102  is located with respect to the surface  302 . 
         [0070]      FIG. 4  illustrates the one side roughened phosphor layer of the present invention placed directly on the LED chip. 
         [0071]    Rather than placing the phosphor layer  104  onto the epoxy layer  106 , the phosphor layer  104  can be placed directly on LED chip  102 , and have a patterned, textured, or roughened upper surface  108  as described previously, such that LED  400  will also have an increased efficiency. The approach shown in LED  400  also reduces reflection of blue light  112 , and increases efficiency, because there is no reflecting surface between the emission of the LED chip  102  and the phosphor layer  104 . 
         [0072]      FIG. 5  illustrates the dual-sided roughened phosphor layer of the present invention placed directly on the LED chip. 
         [0073]    LED  402  shows that a dual-sided roughened phosphor layer  104 , i.e., with surfaces  108  and  302 , can also be placed directly on LED chip  102 , to increase efficiency further. 
         [0074]      FIG. 6  illustrates the one side roughened phosphor layer of the present invention placed inside of the epoxy molding. 
         [0075]    LED  404  uses a phosphor layer  104  inside of the epoxy layer  106 , rather than on top of epoxy layer  106  as shown in  FIGS. 1 and 3 . This protects the phosphor layer  104  and upper surface  108  to allow for long-term high efficiency of LED  404 . 
         [0076]      FIGS. 7 and 8  illustrate the dual-sided roughened phosphor layer of the present invention placed inside of the epoxy molding. 
         [0077]      FIG. 7  shows LED  406  that has an internal phosphor layer  104 , with textured or roughened surfaces  108  and  302 . 
         [0078]      FIGS. 8A and 8B  illustrate an embodiment of the LED of the present invention. 
         [0079]    LED  500  with emitted light  502  and active layer  504  are shown. Lead frame  506  and electrode  508  are shown as supporting glass plate  510 . 
         [0080]    In  FIG. 8 , the LED structure  500  is shown as being grown on a sapphire substrate. Then, Indium Tin Oxide (ITO) layer  512  is deposited on p-type GaN layer  514 . Then, an ITO layer  516  is coated onto glass plate  510 , and is attached to the deposited ITO layer  512  using epoxy as a glue. The other side  518  of glass plate  510  is roughened, patterned, or otherwise given a non-planar profile by a sand blast or other roughening technique, such as etching. Then, the sapphire substrate is removed using the laser de-bonding technique. Then, the Nitrogen-face (N face) GaN  520  is etched with wet etching such as KOH or HCL. Then, a cone-shaped surface  522  is formed on Nitrogen-face GaN  520 . Then, LED chip  500  is put on a lead frame  506  which works for removing any heat that is generated by the LED chip  500 . The wire bonding  524  and  526  is done between bonding pads of the LED chip  528  and  530  and a lead frame  506  and electrode  508  to allow an electric current to flow through the lead frame  506 . There are no intentional mirrors at the front and back sides of LED chip  500 . The lead frame  506  is designed to extract the light from the back side of the LED chip effectively as shown in the figure, because lead frame  506  acts as a support around the edges of LED chip  500 , rather than supporting the entire underside of chip  500 . As such, the LED light  532  is effectively extracted to both sides as emitted light  502 . The ohmic contact below the bonding pad of n—GaN is not shown for simplicity. Then, the LED chip  500  is molded with a sphere shape molding  100  of plastic, epoxy, or glass, which acts as a lens to assist the emitted light  532  to escape from the LED and enter the air. 
         [0081]      FIG. 9  illustrates additional details of an embodiment of the present invention, and  FIG. 10  illustrates details of another embodiment of the present invention. 
         [0082]    In  FIGS. 9 and 10 , instead of the glass layer  510  as shown in  FIG. 5 , a thick epoxy  600  is used. To make the electric contact, the epoxy  600  is partially removed, and ITO or a narrow stripe Au layer  602  is deposited on the epoxy  600  and the hole  604 . The operation of the LED is similar to the LED described with respect to  FIG. 8 , except layer  514  is now roughened on the opposite side of active layer  504  to allow for additional light to be emitted from the reverse side of active layer  502 . 
         [0083]    In  FIGS. 8-10 , if a GaN substrate is used instead of a sapphire substrate, the laser de-bonding step is not required, and, as such, the glass and thick epoxy sub-mount are also not required. After the LED structure growth on GaN substrate, ITO is deposited on p-type GaN and the backside of GaN substrate (typically Nitrogen-face GaN) is etched with a wet etching such as KOH and HCL. Then a cone-shaped surface is formed on the Nitrogen face GaN. The remainder of the fabrication and operational steps are similar to the LED described with respect to  FIG. 8 . 
         [0084]    Also, when the surface of ITO layers, e.g., layers  512 ,  516 , etc., are roughened, the light extraction through the ITO layers  512 ,  516  is increased. Even without the ITO layer  512  that is deposited on the p-type GaN layer  514 , the roughening of the surface of p-type GaN  514  as surface  700  is effective to increase the light extraction through the p-type GaN  514 . To create an ohmic contact for n-type GaN layer  520 , ITO or ZnO are typically used after the surface roughening of Nitrogen-face GaN layer  520 . Since ITO and ZnO have a similar refractive index as GaN, the light reflection at the interface between ITO (ZnO) and GaN is minimized. 
         [0085]      FIGS. 11-14  illustrates embodiments of a spherical LED in accordance with the present invention. 
         [0086]    In  FIG. 11A , the LED chip of  FIG. 5  is molded with epoxy or glass  800  as a sphere shape. In this case, the light  532  is extracted to air through the sphere molding  800  effectively, because the LED chip  500  is a small spot light source compared to the diameter of the spherical lens  800 . In addition, a phosphor layer  802  is placed or deposited near the outside surface of the lens molding  800 . In this case, the conversion efficiency of the blue light to white light is increased due to a small re-absorption of the LED light  532  due to a small back scattering of the LED light  532  by the phosphor layer  802 . Also, when the surface of the molding  800  or the phosphor layer  802  is roughened, the light extraction is increased from the molding  800  and/or the phosphor  802  to the air.  FIG. 11B  illustrates that chip  500  is mounted on frame  506  such that light  532  is also emitted from led  500  via surface  518  on the back side of chip  500 . 
         [0087]    In  FIG. 12 , in the LED chip of  FIGS. 9-10 , the ITO or ZnO is roughened as surface  700  to improve the light extraction through the ITO or ZnO. Then, the epoxy  900  is sub-mounted. 
         [0088]    In  FIG. 13 , before the ITO or ZnO deposition, a current spreading layer (SiO2, SiN, transparent insulating material)  1000  is deposited to allow a uniform current to flow through the p-type GaN layer  512 , and contact  1002  is provided to contact frame  506 . 
         [0089]    In  FIG. 14 , a mirror  1100  is put outside of the sphere molding  800  in order to direct more light to a specific side of the LED package  500 . The shape of the mirror  1100  is typically designed such that any reflected light is directed away from the LED chip  500  to avoid or minimize reabsorption of light by the active layer  502  of the LED chip  500 . 
         [0090]      FIG. 15  illustrates another embodiment of the present invention. 
         [0091]    In  FIG. 15 , LED  1500  comprises an LED structure  1502  with an emitting layer  1504  that is grown on a flat sapphire substrate or a patterned sapphire substrate (PSS)  1506  to improve the light extraction efficiency through the interface between the LED structure  1502  and the sapphire substrate  1506 . Also, the backside of the sapphire substrate  1506  is roughened to increase the light extraction from the sapphire substrate  1506  to the air or epoxy or glass  1508 . A preferred shape of the roughened surface is typically a cone-shaped surface, but other surface topologies can be used without departing from the scope of the present invention. 
         [0092]    Then an ITO or ZnO layer  1510  was deposited on p-type GaN. Then, bonding pad  1512  was formed on the ITO or ZnO layer  1510 , and an Ohmic contact/bonding pad  1514  on n-type GaN layer  1516  are formed after disclosing the n-type GaN by a selective etching through p-type GaN. Wire bonds  1518  and  1520  are added to connect the LED structure  1502  to the lead frame  1522 . 
         [0093]    Then, the LED chip  1502  was molded as an inverted cone-shape for both the front and back sides by shaping epoxy/glass layers  1508  into inverted cone shapes. Then, the phosphor layers  1524  were put near the top surface of the glass/epoxy layers  1508  molding. Typically, this means that the phosphor layer is placed at a distance far away from the LED chip  1502 . In this case, the conversion efficiency of the blue light to white light is increased due to a small re-absorption of the LED light due to a small back scattering by the phosphor to the LED chip. Then the surfaces  1526  and  1528  of the phosphor layers  1524  are roughened to improve the light extraction through the phosphor. The surfaces  1526  and  1528  may have different patterns or may be roughened in the same fashion as each other, as desired. 
         [0094]      FIG. 16  illustrates an internal mirror in accordance with the present invention. 
         [0095]    In  FIG. 16 , a mirror  1600  was put inside of the molding of epoxy/glass layer  1508  shown in  FIG. 15  to increase the light output to a front side  1602  of LED chip  1502 . The shape of the mirror  1600  was designed for the reflected light not to reach the LED chip  1502 . If the reflected light can reach the LED chip  1502 , the LED light  1604  would be re-absorbed by the LED chip  1502 , which decreases the output power or the efficiency of the LED chip  1502 , and thus the efficiency of the LED  1600  would also drop. 
         [0096]    In this case, the mirror  1600  is partially attached to the LED chip  1502  or the substrate  1506 . This partial attachment of the mirror  1600  is not defined as attached mirror to the LED chip  1502  because the mirror of a conventional LED chip is attached to the whole rear surface of the LED chip at the front or the back sides of the LED chip, which would allow for re-absorption of the light within the LED chip, which is undesirable. 
         [0097]    Then, the phosphor layer  1524  was put near the top surface of the molding layer  1508 . Again, this means that the phosphor layer  1524  should be put far away from the LED chip  1502  to allow the light to escape the LED chip  1502 . In this case, the conversion efficiency of the blue light to white light is increased due to a small re-absorption of the LED light due to a small back scattering by the phosphor layer  1524 . Then surface  1528  of the phosphor layer  1524  was roughened to improve the light extraction through the phosphor layer  1524 . 
         [0098]      FIGS. 17A  and B illustrate an emission schema in a direction normal to the LED emissions in accordance with the present invention. 
         [0099]    In  FIG. 17 , LED  1700  comprises mirrors  1702  and  1704  and molding  1508  are designed as shown. The LED light  1604  is obtained from the direction of the side wall, or normal to the top emitting surface of the LED chip  1502 . Then, the phosphor layer  1524  was put near the top surface of the molding  1508 . In this case, the conversion efficiency of the blue light to white light is increased due to a small re-absorption of the LED light  1604  due to a small back scattering by the phosphor layer  1524  to the LED chip. Then the surface  1528  of the phosphor layer  1524  is roughened to improve the conversion efficiency of the phosphor layer  1524  from blue light to yellow light.  FIG. 17B  shows lead frame  1522  with electrodes  1706  and  1708 , which allow light to pass through electrode  1706  through substrate  1506  and contribute to the light emitting from LED  1700 , increasing the efficiency of LED  1700 . Although shown as two mirrors  1702  and  1704 , these mirrors  1702  and  1704  can be a single mirror  1702  that is shaped as a conical or parabolic reflector to maximize the light emitting through surface  1528  if desired. 
         [0100]      FIGS. 18A and 18B  illustrate an alternative embodiment of the emission schema shown in  FIG. 17 . 
         [0101]    In  FIG. 18A , as in  FIG. 17 , LED  1800  has mirrors  1702  and  1704  inside of the molding  1508  removed. In this case, the shape of the molding  1508  is an inverted cone shape. The angle  1802  of the inverted cone is determined for all of the LED light  1604  to reflect to the front side  1804  of LED  1800 . 
         [0102]    For example, the typical refractive index of epoxy is n=1.5. The refractive index of the air is n=1. In such a case, the critical angle of the reflection is sin −1 (1/1.5). So, the angle of the inverted cone  1802  should be more than sin −1 (1/1.5). Then the LED light  1604  is effectively extracted from the front surface  1804  of the inverted cone, which is approximately parallel to the side wall of the LED chip  1502 . A mirror  1806  coating can be applied to the epoxy layer  1508  to increase the reflection of the rear surface of the epoxy layer  1508  if desired. 
         [0103]    Then, the phosphor layer  1524  is put near the top surface of the inverted cone-shape molding  1508 , which places the phosphor layer  1524  relatively far away from the LED chip  1502 . In this case, the conversion efficiency of the blue light to white light is increased due to a small re-absorption of the LED light  1604  due to a small back scattering by the phosphor layer  1524  to the LED chip  1502 . Then surface  1528  of the phosphor layer  1524  is roughened to improve the conversion efficiency of the phosphor layer  1524  from blue to yellow emission. The details of lead frame  1522  are shown in  FIG. 17B . 
         [0104]      FIGS. 19A  and B illustrates another embodiment of the present invention. 
         [0105]    In  FIG. 19A , LED  1900  uses a lead frame  1522  where the LED chip  1502  is placed that also uses a transparent plate  1902  such as glass, quartz and other materials, which is attached to the lead frame using a transparent epoxy  1904  as a die-bonding material. The transparent glass plate is used to extract the LED light  1604  to the epoxy molding  1508  on the underside of LED  1900  effectively. The details of lead frame  1522  are shown in  FIG. 19B . Other portions of LED  1900  are similar to those described with respect to  FIGS. 16-18 . 
         [0106]    Advantages and Improvements 
         [0107]    With a roughening or texturing of the phosphor layer, the conversion efficiency of the phosphor layer is increased by increasing the light extraction from the phosphor layer and also by increasing the excitation efficiency of the phosphor layer. 
         [0108]    Also, without any intentional mirrors attached to LED chip (the mirror coated on lead frame is also included as the intentional mirrors), the re-absorption of LED light is minimized and the light extraction efficiency is increased dramatically. Then, the light output power of the LEDs is increased dramatically. See  FIGS. 4-19 . 
         [0109]    The combination of a transparent oxide electrode with a surface roughened nitride LED and shaped lens results in high light extraction as shown in  FIGS. 4-19 . 
       REFERENCES 
       [0110]    The following references are incorporated by reference herein:
   1. Appl. Phys. Lett. 56, 737-39 (1990).   2. Appl. Phys. Lett. 64, 2839-41 (1994).   3. Appl. Phys. Lett. 81, 3152-54 (2002).   4. Jpn. J. Appl. Phys. 43, L1275-77 (2004).   5. Jpn. J. Appl. Physics, 45, No. 41, L1084-L1086 (2006).   6. Fujii T, Gao Y, Sharma R, Hu E L, DenBaars S P, Nakamura S. Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening. Applied Physics Letters, vol. 84, no. 6, 9 Feb. 2004, pp. 855-7. Publisher: AIP, USA   
 
       CONCLUSION 
       [0117]    In summary, the present invention comprises LEDs with high efficiency. A Light Emitting Diode (LED) in accordance with the present invention comprises an LED chip, emitting light at a first wavelength region, an encapsulation layer, coupled to the LED chip, wherein the encapsulation layer is transparent at the first wavelength region, and a phosphor layer, coupled to the encapsulation layer and distant from the LED chip, the phosphor layer converting the light emitted by the LED chip in the first wavelength region to light in at least a second wavelength region, wherein at least a portion of a surface of the phosphor layer is textured. 
         [0118]    Such an LED further optionally comprises the LED being made from a material selected from the group comprising (Al, Ga, In)N material system, the (Al, Ga, In)As material system, the (Al, Ga, In)P material system, the (Al, Ga, In) AsPNSb material system, and the ZnGeN2 and ZnSnGeN2 material systems, the textured phosphor layer having a cone shape, the encapsulation layer comprising epoxy, glass, air, and other materials that are transparent at the emission wavelength, at least a portion of a second surface of the phosphor layer being textured, the encapsulation layer comprising a material selected from a group comprising ITO, ZnO, and a thin metal, the LED chip further comprising a current spreading layer, a textured sapphire substrate being used for the LED chip to increase the light transmission from the LED chip, a backside of the textured sapphire substrate being textured, the LED being molded into an inverted cone shape, light being extracted from the LED in a direction normal to the emitting surface of the LED chip, a mirror, and the mirror being designed such that light striking the mirror is reflected away from the LED chip. 
         [0119]    Another LED in accordance with the present invention comprises an LED chip, emitting light at a first wavelength region and having a first refractive index, an encapsulation layer, coupled to the LED chip, wherein the encapsulation layer is transparent at the first wavelength region and having a second refractive index less than the first refractive index, wherein the second refractive index is greater than 1, and a phosphor layer, coupled to the encapsulation layer and distant from the LED chip, the phosphor layer converting light emitted in the first wavelength region to light in at least a second wavelength region, wherein at least a portion of a surface of the phosphor layer farthest from the LED chip is not normal to the light emitted from the LED chip. 
         [0120]    Such an LED further optionally comprises the LED being made from a material selected from the group comprising (Al, Ga, In)N material system, the (Al, Ga, In)As material system, the (Al, Ga, In)P material system, the (Al, Ga, In) AsPNSb material system, and the ZnGeN2 and ZnSnGeN2 material systems, the phosphor layer having a cone shape, at least a portion of a second surface of the phosphor layer closer to the LED chip also being textured, the encapsulation layer comprising a material selected from a group comprising ITO, ZnO, and a thin metal, the LED chip further comprising a current spreading layer, and the encapsulation layer comprising epoxy, glass, and other materials that are transparent at the emission wavelength. 
         [0121]    This concludes the description of the preferred embodiment of the present invention. The foregoing description of one or more embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto and the full range of equivalents to the claims appended hereto.