[go: up one dir, main page]

US20080030878A1 - Bi-curvature lens for light emitting diodes and photo detectors - Google Patents

Bi-curvature lens for light emitting diodes and photo detectors Download PDF

Info

Publication number
US20080030878A1
US20080030878A1 US11/835,065 US83506507A US2008030878A1 US 20080030878 A1 US20080030878 A1 US 20080030878A1 US 83506507 A US83506507 A US 83506507A US 2008030878 A1 US2008030878 A1 US 2008030878A1
Authority
US
United States
Prior art keywords
lens
curvature
photo detector
light emitting
light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US11/835,065
Inventor
Kuldeep Saxena
Wee Tan
Peng Ng
Sin Lim
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lite On Technology Corp
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US11/835,065 priority Critical patent/US20080030878A1/en
Publication of US20080030878A1 publication Critical patent/US20080030878A1/en
Assigned to LITE-ON TECHNOLOGY CORP. reassignment LITE-ON TECHNOLOGY CORP. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AVAGO TECHNOLOGIES ECBU IP (SINGAPORE) PTE. LTD.
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of semiconductor or other solid state devices
    • H01L25/03—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/041—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in subclass H10F
    • H01L25/042—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in subclass H10F the devices being arranged next to each other
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/04—Simple or compound lenses with non-spherical faces with continuous faces that are rotationally symmetrical but deviate from a true sphere, e.g. so called "aspheric" lenses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of semiconductor or other solid state devices
    • H01L25/03—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes
    • H01L25/04—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
    • H01L25/075—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H10H20/00
    • H01L25/0753—Assemblies consisting of a plurality of semiconductor or other solid state devices all the devices being of a type provided for in a single subclass of subclasses H10B, H10D, H10F, H10H, H10K or H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H10H20/00 the devices being arranged next to each other
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of semiconductor or other solid state devices
    • H01L25/16—Assemblies consisting of a plurality of semiconductor or other solid state devices the devices being of types provided for in two or more different subclasses of H10B, H10D, H10F, H10H, H10K or H10N, e.g. forming hybrid circuits
    • H01L25/167—Assemblies consisting of a plurality of semiconductor or other solid state devices the devices being of types provided for in two or more different subclasses of H10B, H10D, H10F, H10H, H10K or H10N, e.g. forming hybrid circuits comprising optoelectronic devices, e.g. LED, photodiodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
    • H10D99/00—Subject matter not provided for in other groups of this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F55/00—Radiation-sensitive semiconductor devices covered by groups H10F10/00, H10F19/00 or H10F30/00 being structurally associated with electric light sources and electrically or optically coupled thereto
    • H10F55/18—Radiation-sensitive semiconductor devices covered by groups H10F10/00, H10F19/00 or H10F30/00 being structurally associated with electric light sources and electrically or optically coupled thereto wherein the radiation-sensitive semiconductor devices and the electric light source share a common body having dual-functionality of light emission and light detection
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/40—Optical elements or arrangements
    • H10F77/407—Optical elements or arrangements indirectly associated with the devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F99/00—Subject matter not provided for in other groups of this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H29/00—Integrated devices, or assemblies of multiple devices, comprising at least one light-emitting semiconductor element covered by group H10H20/00
    • H10H29/10—Integrated devices comprising at least one light-emitting semiconductor component covered by group H10H20/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01019—Potassium [K]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/12—Passive devices, e.g. 2 terminal devices
    • H01L2924/1204—Optical Diode
    • H01L2924/12041—LED
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
    • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
    • H10H20/80—Constructional details
    • H10H20/85—Packages
    • H10H20/852—Encapsulations
    • H10H20/853—Encapsulations characterised by their shape

Definitions

  • Embodiments of the present invention pertain generally to wireless communication devices. More specifically, embodiments of the present invention pertain to lenses used with light emitting diodes (LED) or LEDs chip/die and photo detectors (PD) or PDs chip/die in wireless communication devices.
  • LED light emitting diodes
  • PD photo detectors
  • LEDs Light emitting diodes
  • photo detectors are widely used with or without lenses to facilitate wireless infrared communication in devices such as laptop computers, personal digital assistants, printers, mobile phones, modems, digital pagers, electronic cameras, and hand-held computers.
  • devices such as laptop computers, personal digital assistants, printers, mobile phones, modems, digital pagers, electronic cameras, and hand-held computers.
  • the growing popularity of wireless communication has placed a tremendous demand for small form factor for components such as transceivers within wireless communication devices.
  • an infrared transmitter e.g. an LED chip/die with lens
  • an infrared receiver e.g. a photo detector chip/die
  • An embedded LED chip/die with lens is called an emitter.
  • An embedded PD die/chip with lens is called a transmitter.
  • the transmitter and the receiver are connected with an integrated circuit for signal processing.
  • On the surface of the transceiver there are two lenses.
  • a light emitting diode chip/die is located in or near the center of one of the lenses, and a photo detector chip/die is located in or near the center of the other lens.
  • spherical lenses 110 described by a radius r ( 115 ), as depicted in FIG. 1 are employed to ensure proper directional distribution of light.
  • a steradian 210 is a three dimensional unit of spherical geometry, depicted in FIG. 2 .
  • One steradian 210 is a solid angle, e.g. a cone that, having its vertex 221 in the center of a sphere 201 of radius r ( 205 ), cuts off an area ( 220 ) on the surface of the sphere equal to that of a square with sides of length equal to the radius r of the sphere.
  • one steradian 210 is a solid angle defining an area 220 equal to r 2 on the surface of a sphere 201 described by radius r ( 205 ).
  • a radiant intensity profile for a spherical lens is presented in FIG. 3 .
  • the curve of flux per steradian in a horizontal direction 310 is substantially symmetrical about the maximum 330 .
  • the curve of flux per steradian in a vertical direction 320 is also substantially symmetrical about the maximum 330 .
  • This symmetry in both the vertical and horizontal directions is required to satisfy the standards and protocols of the Infrared Data Association (IrDA), a non-profit organization dedicated to developing globally adopted specifications for infrared wireless communication.
  • IrDA Infrared Data Association
  • One approach to meeting the current demand for smaller components within wireless devices is to manufacture smaller spherical lenses for use with LEDs and photo detectors in infrared transceivers.
  • the diameter is decreased for spherical lenses used with LEDs, the brightness of the LEDs decreases, therefore signal output is compromised.
  • the diameter is decreased on spherical lenses used with photo detectors, less light is received at the photo detector, therefore signal processing is compromised.
  • Embodiments of the present invention a light emitting device having a light emitting diode chip/die and a bi-curvature dome lens are disclosed.
  • the bi-curvature dome lens according to embodiments of the present invention has a hemispherical bottom portion defined by a first radius and an aspherical upper portion defined by a second radius and a conic constant.
  • FIG. 1 is an illustration of a conventional spherical dome lens for an LED chip/die.
  • FIG. 2 illustrates a steradian
  • FIG. 3 is a radiant intensity profile of a conventional spherical dome lens with an LED chip/die.
  • FIG. 4 depicts a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 5 is a radiant intensity profile of a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 6 depicts a light emitting device with a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 7 depicts a light receiving device with a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 8 illustrates a transceiver having bi-curvature dome lenses in accordance with embodiments of the present invention.
  • FIG. 9 is a flowchart reciting steps in a method of designing a bi-curvature dome lens.
  • FIG. 10 is a flowchart illustrating steps in a method of fabricating an emitter and/or receiver LED and/or photo detector device disclosed in the present invention.
  • One embodiment of the present invention is a bi-curvature dome shaped lens 400 , depicted in FIG. 4 .
  • the profile of a bi-curvature lens is defined by two curvatures, hence the term “bi-curvature.”
  • the bottom portion 410 of the dome 400 has a hemispherical contour 411 , and radius r 1 ( 415 ).
  • the top portion 420 has an aspheric contour 421 , a radius of curvature r 2 ( 425 ) and a conic constant k.
  • the conic constant k is a function of the eccentricity of the aspheric contour, where the eccentricity defines the deviation from spherical of the aspherical contour.
  • the conic constant is zero.
  • aspherical in this context, refers to a surface or contour that is not spherical, e.g. the conic constant is not equal to zero.
  • the aspherical contour 421 is an elliptical contour.
  • FIG. 5 illustrates a radiant intensity profile 500 of the light distribution of an LED having a bi-curvature lens (as in FIG. 4 ) according to embodiments of the present invention.
  • the flux per steradian in the horizontal direction ( 510 ) is symmetrical about the maximum 530 .
  • the flux per steradian in the vertical direction ( 520 ) is also symmetrical about he maximum 530 . Symmetry about the maximum in both the horizontal and vertical directions of radiant intensity is required to satisfy Infrared Data Association (IrDA) standards and protocol.
  • IrDA Infrared Data Association
  • a bi-curvature lens 601 can be used to direct light 610 emitted from a light emitting diode chip/die 620 , e.g. an infrared emitting device, according to one embodiment of the present invention.
  • a bi-curvature lens 701 according to embodiments of the present invention can also be used to direct light 710 for detection at a photo detector 720 , as illustrated in FIG. 7 .
  • the photo detector 720 depicted in FIG. 7 is a photo detector chip, and in another embodiment, the photo detector 720 depicted in FIG. 7 is a photo detector die.
  • a bi-curvature dome lens in accordance with embodiments of the present invention could be employed to guide any wavelength of visible light, infrared light, ultraviolet, or other light.
  • Light transmitted through a bi-curvature dome lens in accordance with embodiments of the present invention will display symmetry of radiant intensity along the horizontal and the vertical directions, as required by the IrDA.
  • the diameter of a lens in accordance with the present invention can be smaller than the diameter of a conventional spherical lens.
  • a transceiver having bi-curvature lenses can be smaller and more compact than a transceiver having spherical lenses.
  • a wireless communication device having transceivers with bi-curvature lenses can be smaller and more compact than a wireless communication device having transceivers with conventional spherical lenses.
  • FIG. 8 illustrates a wireless communication transceiver 800 , in one embodiment an infrared wireless communication transceiver.
  • An LED chip 820 is attached with a PCB substrate 810 by a bondable wire 821 .
  • a photo detector chip 830 is attached with PCB substrate 810 by a bondable wire 831 .
  • a layer of epoxy 840 covers the LED chip 820 and the photo detector chip 830 .
  • Light 865 emitted by the LED chip 820 is transmitted through a bi-curvature lens 860 to produce symmetrical radiant intensity in both the horizontal and vertical directions, as illustrated by the radiant intensity profile of FIG. 5 .
  • Light 855 transmitted through a bi-curvature lens 850 in accordance with the present invention is received at the photo detector chip 830 .
  • One embodiment of the present invention is the design method employed to obtain a bi-curvature dome capable of emitting light of symmetrical radiant intensity, in both the horizontal and the vertical directions.
  • One design method is recited in flowchart 900 of FIG. 9 .
  • a spherical structure e.g. a hemispherical structure
  • a sequential ray trace program can then be employed to develop an aspheric contour ( 421 in FIG. 4 ) for the top portion ( 420 in FIG. 4 ) of the dome ( 400 in FIG. 4 ), as described in step 920 of flowchart 900 .
  • a subsequent step 930 is the simulation of a bi-curvature dome ( 400 in FIG. 4 ) that combines the spherical bottom portion ( 410 in FIG. 4 ) simulated at step 910 and the aspherical top portion ( 420 in FIG. 4 ) simulated at step 920 .
  • a radiation intensity profile e.g. FIG. 5
  • the radiation intensity profile simulated at step 940 is evaluated at step 950 .
  • the radiation intensity profile simulated at step 940 is desirable if it is symmetric about a maximum in both the horizontal and the vertical directions, as in FIG. 5 . If the radiation intensity profile is satisfactory, the design process is done. If the radiation intensity profile is not satisfactory, e.g. not substantially symmetric about a maximum in both the horizontal and the vertical directions, certain parameters of the design can be altered, as in step 960 in flowchart 900 . For example, referring to FIG. 4 , the contour 421 of the aspheric portion 420 of the lens 400 could be modified by increasing or decreasing the radius of curvature r 2 425 or the conic constant k.
  • Another example of a parameter that can be altered is the proportion of the bottom spherical portion 410 and the top aspherical portion 420 with respect to the height of the dome 400 .
  • various iterations are carried out until a desired radiant intensity distribution is obtained. Referring to flowchart 900 , steps 940 - 970 are repeated until substantially symmetry is achieved in the radiant intensity profile simulated at step 940 .
  • a wireless communication transceiver is fabricated by a transfer mold method as recited in flowchart 1000 of FIG. 10 .
  • at least one diode chip such as an LED chip (e.g. an IRED chip) or an infrared photo detector chip is attached to a printed circuit board (PCB) substrate, as recited in step 1010 .
  • an LED chip and a photo detector chip are attached to the printed circuit board, adjacent to each other, as depicted in FIG. 8 .
  • Each chip is wire bonded to an electrical terminal of the PCB substrate.
  • a layer of epoxy may be formed on the surface of the printed circuit board substrate, covering the diode(s).
  • the PCB substrate is located on a transfer mold fixture that has molds for bi-curvature lenses in accordance with embodiments of the bi-curvature dome lens of the present invention.
  • an encapsulant is then cast to fill the bi-curvature lens mold, followed by a heat cure in step 1040 to ensure that the bi-curvature dome lenses have the desired properties for light emission and/or reception.
  • the printed circuit board is ready to be singulated into individual light emitting units, photo detector units, or transceiver units, as recited in step 1050 . Singulation of the PCB may be accomplished by proper sawing.
  • the bi-curvature dome lens of the present invention can be formed from any material rendering efficient light transmission.
  • a bi-curvature dome lens in accordance with embodiments of the present invention is not limited to infrared wireless communication applications.
  • Embodiments of the present invention permit optics designers to achieve desired radiant intensity profiles using very small lenses, e.g. lenses having very small diameters.
  • the cost of fabrication of bi-curvature lenses is comparable to the cost of fabrication of conventional spherical lenses.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • Optics & Photonics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Led Device Packages (AREA)
  • Electromagnetism (AREA)
  • Light Receiving Elements (AREA)
  • Optical Communication System (AREA)

Abstract

A bi-curvature lens for diodes in an infrared wireless communication transceiver is disclosed. Devices having such a bi-curvature lens, such as a light emitting device, a light detecting device, and a transceiver are also disclosed. A method for designing such a lens, and a method for fabricating a device having such a lens are also disclosed. The bi-curvature lens disclosed has a bottom hemispherical portion and a top aspherical portion. Light emitting diodes and photo detectors used in conjunction with bi-curvature lenses display symmetrical radiation intensity profiles, in accordance with Infrared Data Association standards and protocols.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This is a divisional continuation application of copending application Ser. No. 11/074,883 of Kuldeep Kumar Saxena et al., filed Mar. 7, 2005, for BI-CURVATURE LENS FOR LIGHT EMITTING DIODES AND PHOTO DETECTORS, the entire disclosure of which is hereby incorporated by reference herein.
    • FIELD OF THE INVENTION
  • Embodiments of the present invention pertain generally to wireless communication devices. More specifically, embodiments of the present invention pertain to lenses used with light emitting diodes (LED) or LEDs chip/die and photo detectors (PD) or PDs chip/die in wireless communication devices.
    • BACKGROUND OF THE INVENTION
  • Light emitting diodes (LEDs) and photo detectors are widely used with or without lenses to facilitate wireless infrared communication in devices such as laptop computers, personal digital assistants, printers, mobile phones, modems, digital pagers, electronic cameras, and hand-held computers. The growing popularity of wireless communication has placed a tremendous demand for small form factor for components such as transceivers within wireless communication devices.
  • In a typical wireless communication device, an infrared transmitter (e.g. an LED chip/die with lens) is arranged adjacent to an infrared receiver (e.g. a photo detector chip/die) in an arrangement called a transceiver. An embedded LED chip/die with lens is called an emitter. An embedded PD die/chip with lens is called a transmitter. The transmitter and the receiver are connected with an integrated circuit for signal processing. On the surface of the transceiver, there are two lenses. A light emitting diode chip/die is located in or near the center of one of the lenses, and a photo detector chip/die is located in or near the center of the other lens. Conventionally, spherical lenses 110 described by a radius r (115), as depicted in FIG. 1, are employed to ensure proper directional distribution of light.
  • One method of evaluating LED lenses is the generation of a radiant intensity profile. The radiant intensity profile indicates flux of radiation per steradian of the surface of a lens. The term flux, in this context, refers to the energy per steradian of the emission of the LED. A steradian 210 is a three dimensional unit of spherical geometry, depicted in FIG. 2. One steradian 210 is a solid angle, e.g. a cone that, having its vertex 221 in the center of a sphere 201 of radius r (205), cuts off an area (220) on the surface of the sphere equal to that of a square with sides of length equal to the radius r of the sphere. In other words, one steradian 210 is a solid angle defining an area 220 equal to r2 on the surface of a sphere 201 described by radius r (205).
  • A radiant intensity profile for a spherical lens is presented in FIG. 3. The curve of flux per steradian in a horizontal direction 310 is substantially symmetrical about the maximum 330. The curve of flux per steradian in a vertical direction 320 is also substantially symmetrical about the maximum 330. This symmetry in both the vertical and horizontal directions is required to satisfy the standards and protocols of the Infrared Data Association (IrDA), a non-profit organization dedicated to developing globally adopted specifications for infrared wireless communication. As can be appreciated, it is desirable for a commercially available device to conform to IrDA standards and protocols.
  • One approach to meeting the current demand for smaller components within wireless devices is to manufacture smaller spherical lenses for use with LEDs and photo detectors in infrared transceivers. However, as the diameter is decreased for spherical lenses used with LEDs, the brightness of the LEDs decreases, therefore signal output is compromised. As the diameter is decreased on spherical lenses used with photo detectors, less light is received at the photo detector, therefore signal processing is compromised.
    • SUMMARY OF THE INVENTION
  • Embodiments of the present invention, a light emitting device having a light emitting diode chip/die and a bi-curvature dome lens are disclosed. The bi-curvature dome lens according to embodiments of the present invention has a hemispherical bottom portion defined by a first radius and an aspherical upper portion defined by a second radius and a conic constant.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention:
  • FIG. 1 is an illustration of a conventional spherical dome lens for an LED chip/die.
  • FIG. 2 illustrates a steradian.
  • FIG. 3 is a radiant intensity profile of a conventional spherical dome lens with an LED chip/die.
  • FIG. 4 depicts a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 5 is a radiant intensity profile of a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 6 depicts a light emitting device with a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 7 depicts a light receiving device with a bi-curvature dome lens in accordance with embodiments of the present invention.
  • FIG. 8 illustrates a transceiver having bi-curvature dome lenses in accordance with embodiments of the present invention.
  • FIG. 9 is a flowchart reciting steps in a method of designing a bi-curvature dome lens.
  • FIG. 10 is a flowchart illustrating steps in a method of fabricating an emitter and/or receiver LED and/or photo detector device disclosed in the present invention.
    • DETAILED DESCRIPTION
  • Reference will now be made in detail to various embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with various embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and the scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, structures and devices have not been described in detail so as to avoid unnecessarily obscuring aspects of the present invention.
  • One embodiment of the present invention is a bi-curvature dome shaped lens 400, depicted in FIG. 4. The profile of a bi-curvature lens is defined by two curvatures, hence the term “bi-curvature.” As illustrated in FIG. 4, the bottom portion 410 of the dome 400 has a hemispherical contour 411, and radius r1 (415). The top portion 420 has an aspheric contour 421, a radius of curvature r2 (425) and a conic constant k. The conic constant k is a function of the eccentricity of the aspheric contour, where the eccentricity defines the deviation from spherical of the aspherical contour. For a sphere, the conic constant is zero. The term aspherical, in this context, refers to a surface or contour that is not spherical, e.g. the conic constant is not equal to zero. In one embodiment, the aspherical contour 421 is an elliptical contour.
  • FIG. 5 illustrates a radiant intensity profile 500 of the light distribution of an LED having a bi-curvature lens (as in FIG. 4) according to embodiments of the present invention. The flux per steradian in the horizontal direction (510) is symmetrical about the maximum 530. The flux per steradian in the vertical direction (520) is also symmetrical about he maximum 530. Symmetry about the maximum in both the horizontal and vertical directions of radiant intensity is required to satisfy Infrared Data Association (IrDA) standards and protocol.
  • Referring now to FIG. 6, a bi-curvature lens 601 can be used to direct light 610 emitted from a light emitting diode chip/die 620, e.g. an infrared emitting device, according to one embodiment of the present invention. A bi-curvature lens 701 according to embodiments of the present invention can also be used to direct light 710 for detection at a photo detector 720, as illustrated in FIG. 7. In one embodiment, the photo detector 720 depicted in FIG. 7 is a photo detector chip, and in another embodiment, the photo detector 720 depicted in FIG. 7 is a photo detector die. A bi-curvature dome lens in accordance with embodiments of the present invention could be employed to guide any wavelength of visible light, infrared light, ultraviolet, or other light. Light transmitted through a bi-curvature dome lens in accordance with embodiments of the present invention will display symmetry of radiant intensity along the horizontal and the vertical directions, as required by the IrDA.
  • The diameter of a lens in accordance with the present invention can be smaller than the diameter of a conventional spherical lens. Thus, a transceiver having bi-curvature lenses can be smaller and more compact than a transceiver having spherical lenses. A wireless communication device having transceivers with bi-curvature lenses can be smaller and more compact than a wireless communication device having transceivers with conventional spherical lenses.
  • FIG. 8 illustrates a wireless communication transceiver 800, in one embodiment an infrared wireless communication transceiver. An LED chip 820 is attached with a PCB substrate 810 by a bondable wire 821. A photo detector chip 830 is attached with PCB substrate 810 by a bondable wire 831. A layer of epoxy 840 covers the LED chip 820 and the photo detector chip 830. Light 865 emitted by the LED chip 820 is transmitted through a bi-curvature lens 860 to produce symmetrical radiant intensity in both the horizontal and vertical directions, as illustrated by the radiant intensity profile of FIG. 5. Light 855 transmitted through a bi-curvature lens 850 in accordance with the present invention is received at the photo detector chip 830.
  • One embodiment of the present invention is the design method employed to obtain a bi-curvature dome capable of emitting light of symmetrical radiant intensity, in both the horizontal and the vertical directions. One design method is recited in flowchart 900 of FIG. 9. Initially, a spherical structure, e.g. a hemispherical structure, is simulated for the bottom portion (410 in FIG. 4) of the bi-curvature lens (400 in FIG. 4), as in step 910. A sequential ray trace program can then be employed to develop an aspheric contour (421 in FIG. 4) for the top portion (420 in FIG. 4) of the dome (400 in FIG. 4), as described in step 920 of flowchart 900. A subsequent step 930 is the simulation of a bi-curvature dome (400 in FIG. 4) that combines the spherical bottom portion (410 in FIG. 4) simulated at step 910 and the aspherical top portion (420 in FIG. 4) simulated at step 920. Once the combination bi-curvature dome structure has been developed at step 930, a radiation intensity profile (e.g. FIG. 5) is simulated through the entire dome structure (400 in FIG. 4), as indicated by step 940 in flowchart 900. The radiation intensity profile simulated at step 940 is evaluated at step 950. At step 970, it is determined whether or not the radiation intensity profile simulated at step 940 is desirable. The radiation intensity profile simulated at step 940 is desirable if it is symmetric about a maximum in both the horizontal and the vertical directions, as in FIG. 5. If the radiation intensity profile is satisfactory, the design process is done. If the radiation intensity profile is not satisfactory, e.g. not substantially symmetric about a maximum in both the horizontal and the vertical directions, certain parameters of the design can be altered, as in step 960 in flowchart 900. For example, referring to FIG. 4, the contour 421 of the aspheric portion 420 of the lens 400 could be modified by increasing or decreasing the radius of curvature r2 425 or the conic constant k. Another example of a parameter that can be altered is the proportion of the bottom spherical portion 410 and the top aspherical portion 420 with respect to the height of the dome 400. According to an embodiment of the present invention, various iterations are carried out until a desired radiant intensity distribution is obtained. Referring to flowchart 900, steps 940-970 are repeated until substantially symmetry is achieved in the radiant intensity profile simulated at step 940.
  • In one embodiment, a wireless communication transceiver is fabricated by a transfer mold method as recited in flowchart 1000 of FIG. 10. Initially, at least one diode chip, such as an LED chip (e.g. an IRED chip) or an infrared photo detector chip is attached to a printed circuit board (PCB) substrate, as recited in step 1010. For a transceiver, an LED chip and a photo detector chip are attached to the printed circuit board, adjacent to each other, as depicted in FIG. 8. Each chip is wire bonded to an electrical terminal of the PCB substrate. A layer of epoxy may be formed on the surface of the printed circuit board substrate, covering the diode(s). Subsequently, as recited in step 1020, the PCB substrate is located on a transfer mold fixture that has molds for bi-curvature lenses in accordance with embodiments of the bi-curvature dome lens of the present invention. Proceeding to step 1030, an encapsulant is then cast to fill the bi-curvature lens mold, followed by a heat cure in step 1040 to ensure that the bi-curvature dome lenses have the desired properties for light emission and/or reception. After a heat cure, the printed circuit board is ready to be singulated into individual light emitting units, photo detector units, or transceiver units, as recited in step 1050. Singulation of the PCB may be accomplished by proper sawing.
  • It can be appreciated that the bi-curvature dome lens of the present invention can be formed from any material rendering efficient light transmission. A bi-curvature dome lens in accordance with embodiments of the present invention is not limited to infrared wireless communication applications. Embodiments of the present invention permit optics designers to achieve desired radiant intensity profiles using very small lenses, e.g. lenses having very small diameters. The cost of fabrication of bi-curvature lenses is comparable to the cost of fabrication of conventional spherical lenses.
  • The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations are possible in light of the above teaching. The embodiments of were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (4)

1. A light detecting device comprising:
a photo detector; and
a bi-curvature dome lens comprising:
a hemispherical portion comprising a first radius; and
an aspherical portion comprising a second radius and a conic constant not equal to zero.
2. The light detecting device of claim 1 wherein said photo detector is a photo detector chip, wherein said photo detector chip is embedded in said bi-curvature dome lens.
3. The light detecting device of claim 1 wherein said photo detector is a photo detector die, wherein said photo detector chip is embedded in said bi-curvature dome lens.
4. A method of detecting light comprising:
transmitting light through a bi-curvature lens, said lens comprising a first hemispherical portion and a second aspherical portion; and
receiving light at a photo detector.
US11/835,065 2005-03-07 2007-08-07 Bi-curvature lens for light emitting diodes and photo detectors Abandoned US20080030878A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US11/835,065 US20080030878A1 (en) 2005-03-07 2007-08-07 Bi-curvature lens for light emitting diodes and photo detectors

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11/074,883 US7271963B2 (en) 2005-03-07 2005-03-07 Bi-curvature lens for light emitting diodes and photo detectors
US11/835,065 US20080030878A1 (en) 2005-03-07 2007-08-07 Bi-curvature lens for light emitting diodes and photo detectors

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US11/074,883 Division US7271963B2 (en) 2005-03-07 2005-03-07 Bi-curvature lens for light emitting diodes and photo detectors

Publications (1)

Publication Number Publication Date
US20080030878A1 true US20080030878A1 (en) 2008-02-07

Family

ID=36219213

Family Applications (2)

Application Number Title Priority Date Filing Date
US11/074,883 Expired - Fee Related US7271963B2 (en) 2005-03-07 2005-03-07 Bi-curvature lens for light emitting diodes and photo detectors
US11/835,065 Abandoned US20080030878A1 (en) 2005-03-07 2007-08-07 Bi-curvature lens for light emitting diodes and photo detectors

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US11/074,883 Expired - Fee Related US7271963B2 (en) 2005-03-07 2005-03-07 Bi-curvature lens for light emitting diodes and photo detectors

Country Status (4)

Country Link
US (2) US7271963B2 (en)
JP (1) JP2006253678A (en)
CN (1) CN100568553C (en)
GB (1) GB2424123A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100033987A1 (en) * 2008-08-05 2010-02-11 Au Optronics Corporation Backlight Module and Light Emitting Diode Module Thereof
US20100327164A1 (en) * 2009-06-30 2010-12-30 Avago Technologies Ecbu (Singapore) Pte. Ltd. Optical Proximity Sensor Package with Molded Infrared Light Rejection Barrier and Infrared Pass Components
US20110057108A1 (en) * 2009-09-10 2011-03-10 Avago Technologies Ecbu (Singapore) Pte. Ltd. Compact Optical Proximity Sensor with Ball Grid Array and Windowed Substrate
US20110121181A1 (en) * 2009-11-23 2011-05-26 Avago Technologies Ecbu (Singapore) Pte. Ltd. Infrared Proximity Sensor Package with Improved Crosstalk Isolation
US20130292706A1 (en) * 2009-06-30 2013-11-07 Avago Technologies General Ip (Singapore) Pte. Ltd. Infrared Attenuating Or Blocking Layer In Optical Proximity Sensor
US8841597B2 (en) 2010-12-27 2014-09-23 Avago Technologies Ip (Singapore) Pte. Ltd. Housing for optical proximity sensor

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10340424B2 (en) 2002-08-30 2019-07-02 GE Lighting Solutions, LLC Light emitting diode component
KR100622209B1 (en) 2002-08-30 2006-09-19 젤코어 엘엘씨 Coated led with improved efficiency
US7800121B2 (en) 2002-08-30 2010-09-21 Lumination Llc Light emitting diode component
US8130210B2 (en) * 2004-11-30 2012-03-06 Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. Touch input system using light guides
US7501659B2 (en) * 2005-04-12 2009-03-10 Japan Cash Machine Co., Ltd. LED device and optical detector therewith for bill validator
GB2444336B (en) * 2005-09-13 2009-02-25 Higher Way Electronic Co Ltd Solar-powered illuminator
US20080123328A1 (en) * 2006-11-29 2008-05-29 Higher Way Electronic Co., Ltd. Solar-powered illuminator
US7842960B2 (en) 2006-09-06 2010-11-30 Lumination Llc Light emitting packages and methods of making same
CN101626053B (en) * 2008-07-10 2011-12-07 一品光学工业股份有限公司 Aspherical positive angle optical lens and light-emitting diode assembly formed therefrom
US8957380B2 (en) 2009-06-30 2015-02-17 Avago Technologies General Ip (Singapore) Pte. Ltd. Infrared attenuating or blocking layer in optical proximity sensor
US8593040B2 (en) 2009-10-02 2013-11-26 Ge Lighting Solutions Llc LED lamp with surface area enhancing fins
EP2664219A2 (en) * 2011-01-13 2013-11-20 Koninklijke Philips N.V. Light system and method
TWI435481B (en) * 2011-02-18 2014-04-21 Genesis Photonics Inc Light emitting diode device
US9500355B2 (en) 2012-05-04 2016-11-22 GE Lighting Solutions, LLC Lamp with light emitting elements surrounding active cooling device
KR101596653B1 (en) * 2012-11-13 2016-02-22 바이올렛 디펜스 테크놀로지, 인크. Device for ultraviolet light emission
JP6137839B2 (en) * 2013-01-15 2017-05-31 三菱電機株式会社 Receiving optical system
WO2016206716A1 (en) * 2015-06-23 2016-12-29 Aktiebolaget Electrolux Remotely controlled robotic cleaning device

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3532821A1 (en) * 1985-09-13 1987-03-26 Siemens Ag LIGHT-EMITTING DIODE (LED) WITH SPHERICAL LENS
JPH02106056A (en) 1988-10-14 1990-04-18 Matsushita Electron Corp Cap with lens window
US5751492A (en) 1996-06-14 1998-05-12 Eastman Kodak Company Diffractive/Refractive lenslet array incorporating a second aspheric surface
ES2157846B1 (en) 1999-12-02 2002-03-01 Univ Madrid Politecnica DEVICE WITH DISCONTINUOUS LENS WITH INTERNAL TOTAL REFLECTION AND ASPHERIC DIOPTRIC FOR CONCENTRATION OR COLIMATION OF RADIANT ENERGY.
JP2001281541A (en) 2000-03-28 2001-10-10 Matsushita Electric Works Ltd Infrared transmitting element
US20040126064A1 (en) * 2002-12-31 2004-07-01 Vandentop Gilroy J. Optical assembly
US7302181B2 (en) 2003-02-25 2007-11-27 Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. Single lens multiple light source device

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100033987A1 (en) * 2008-08-05 2010-02-11 Au Optronics Corporation Backlight Module and Light Emitting Diode Module Thereof
US8222664B2 (en) 2008-08-05 2012-07-17 Au Optronics Corporation Backlight module and light emitting diode module thereof
US8324655B2 (en) 2008-08-05 2012-12-04 Au Optronics Corporation Backlight module and light emitting diode module thereof
US20100327164A1 (en) * 2009-06-30 2010-12-30 Avago Technologies Ecbu (Singapore) Pte. Ltd. Optical Proximity Sensor Package with Molded Infrared Light Rejection Barrier and Infrared Pass Components
US20130292706A1 (en) * 2009-06-30 2013-11-07 Avago Technologies General Ip (Singapore) Pte. Ltd. Infrared Attenuating Or Blocking Layer In Optical Proximity Sensor
US8779361B2 (en) 2009-06-30 2014-07-15 Avago Technologies General Ip (Singapore) Pte. Ltd. Optical proximity sensor package with molded infrared light rejection barrier and infrared pass components
US9525093B2 (en) * 2009-06-30 2016-12-20 Avago Technologies General Ip (Singapore) Pte. Ltd. Infrared attenuating or blocking layer in optical proximity sensor
US20110057108A1 (en) * 2009-09-10 2011-03-10 Avago Technologies Ecbu (Singapore) Pte. Ltd. Compact Optical Proximity Sensor with Ball Grid Array and Windowed Substrate
US8716665B2 (en) 2009-09-10 2014-05-06 Avago Technologies General Ip (Singapore) Pte. Ltd. Compact optical proximity sensor with ball grid array and windowed substrate
US20110121181A1 (en) * 2009-11-23 2011-05-26 Avago Technologies Ecbu (Singapore) Pte. Ltd. Infrared Proximity Sensor Package with Improved Crosstalk Isolation
US9733357B2 (en) 2009-11-23 2017-08-15 Avago Technologies General Ip (Singapore) Pte. Ltd. Infrared proximity sensor package with improved crosstalk isolation
US8841597B2 (en) 2010-12-27 2014-09-23 Avago Technologies Ip (Singapore) Pte. Ltd. Housing for optical proximity sensor

Also Published As

Publication number Publication date
GB0604476D0 (en) 2006-04-12
GB2424123A (en) 2006-09-13
CN100568553C (en) 2009-12-09
JP2006253678A (en) 2006-09-21
CN1832217A (en) 2006-09-13
US7271963B2 (en) 2007-09-18
US20060198032A1 (en) 2006-09-07

Similar Documents

Publication Publication Date Title
US20080030878A1 (en) Bi-curvature lens for light emitting diodes and photo detectors
CN105283706B (en) Optical texture, lighting unit and manufacture method
KR100638611B1 (en) Multi Lens Light Emitting Diode
US9897266B2 (en) Light source module and lighting apparatus including the same
US20170059763A1 (en) LED and Laser Light Coupling Device and Method of Use
US20110044022A1 (en) System and method for a phosphor coated lens
US8845115B2 (en) Flash illumination system
US20070114549A1 (en) Light-emitting diode
US7748912B2 (en) Double mold optocouplers
JP2005276794A (en) Light source device
US20150036347A1 (en) Compound lens and led light source device incorporating the same
US20130148328A1 (en) Lighting device
CN108614383A (en) Floodlight assembly, floodlight damage detection method and electronic device
US20090122395A1 (en) Light emitting device, light receiving device, spatial transmission device, lens design method, and illuminating device
CN103477145B (en) There is the solid-state light module of infundibulate phosphor surface
US11322852B2 (en) Lens antenna packaging structure, preparation method and electronic device
US20130128590A1 (en) Led unit
US20110110101A1 (en) Led unit
Garcia-Marquez et al. Catadioptric lenses in visible light communications
JP2010268218A (en) Infrared communication device, optical space transmission apparatus and communication system
US20100033091A1 (en) Light emitting unit and method of manufacturing the light emitting unit
WO2016123341A1 (en) Omni-directional light emitting device
Wang et al. Novel Application-Specific LED Packages Integrated With Compact Freeform Lens

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION

AS Assignment

Owner name: LITE-ON TECHNOLOGY CORP., TAIWAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:AVAGO TECHNOLOGIES ECBU IP (SINGAPORE) PTE. LTD.;REEL/FRAME:023168/0303

Effective date: 20090702