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  Array of light emitting devices to produce a white light sourceUSPTO Application #: 20060105482Title: Array of light emitting devices to produce a white light source Abstract: A device is provided with an array of a plurality of phosphor converted light emitting devices (LEDs) that produce broad spectrum light. The phosphor converted LEDs may produce light with different correlated color temperature (CCT) and are covered with an optical element that assists in mixing the light from the LEDs to produce a desired correlated color temperature. The phosphor converted LEDs may also be combined in an array with color LEDs. The color LEDs may be controlled to vary their brightness such that light with an approximately continuous broad spectrum is produced. By controlling the brightness of the color LEDs, light can be produced with a fixed brightness over a large range of white points with a high color rendering quality. (end of abstract) Agent: Patent Law Group LLP - San Jose, CA, US Inventors: Robertus G. Alferink, Michael R. Krames USPTO Applicaton #: 20060105482 - Class: 438022000 (USPTO) Related Patent Categories: Semiconductor Device Manufacturing: Process, Making Device Or Circuit Emissive Of Nonelectrical Signal The Patent Description & Claims data below is from USPTO Patent Application 20060105482. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATION [0001] The present application is a continuation of and claims priority to U.S. patent application Ser. No. 10/987,241, filed Nov. 12, 2004, entitled "Bonding an Optical Element to a Light Emitting Device", by Michael D. Camras et al, which is incorporated herein by reference. FIELD OF THE INVENTION [0002] The present invention relates generally to light emitting devices and, more particularly, to an array of light emitting devices to produce a white light source. BACKGROUND [0003] Adding or mixing a number of different color light emitting devices (LEDs) can be used to produce light with a broad spectrum. The spectrum produced, however, consists of the peaks of the narrow band spectra produced by the individual LEDs. Consequently, the color rendering of such a light source is poor. White light sources with high color rendering, such as that produced by a halogen lamp, have a continuous or near continuous spectrum over the full visible light spectrum (400-700 nm). [0004] Thus, a white light source with high color rendering that is produced using an array of LEDs is desired SUMMARY [0005] In accordance with one embodiment of the present invention, a plurality of phosphor converted light emitting devices may be combined in an array to obtain light with a desired correlated color temperature (CCT). In one embodiment, the phosphor converted light emitting devices produce light with different CCTs. An array of the plurality of phosphor converted light emitting devices may be covered with an optical element that optionally can be filled with a material that assists in light extraction and mixing the light to produce light with the desired CCT. In another embodiment, a plurality of color light emitting devices are combined with the plurality of phosphor converted light emitting devices and the brightness of the color light emitting devices are controlled to produce light with the desired characteristics. BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1A illustrates a side view of an LED die mounted on a submount and an optical element that is to be bonded to the LED die. [0007] FIG. 1B illustrates the optical element bonded to the LED die. [0008] FIG. 2 illustrates an embodiment in which multiple LED dice are mounted to a submount and a separate optical element is bonded to each LED die. [0009] FIG. 3 illustrates an embodiment in which multiple LED dice are mounted to a submount and a single optical element is bonded to the LED dice. [0010] FIG. 4 is a flow chart of one implementation of producing such an LED device with wavelength converting material covering the optical element. [0011] FIG. 5 illustrates an embodiment in which a layer of wavelength converting material is disposed between the bonding layer and the optical element. [0012] FIG. 6 illustrates an embodiment in which a layer of wavelength converting material is deposited on the LED die. [0013] FIG. 7 illustrates an array of LEDs, which are mounted on a board. [0014] FIG. 8 is a graph of the broad spectrum produced by a phosphor converted blue LED. [0015] FIG. 9 is a CIE chromaticity diagram for the spectrum shown in FIG. 8. [0016] FIG. 10 is a graph of the spectra produced by phosphor converted LEDs and colored LEDs, which are combined to produce an approximately continuous spectrum. [0017] FIG. 11 is a portion of a CIE chromaticity diagram that shows the variation in the CCT that may be produced by varying the brightness of the colored LEDs. [0018] FIG. 12 is a portion of another CIE chromaticity diagram that illustrates variable CCT values for an array of 29 phosphor converted LEDs and 12 color LEDs. DETAILED DESCRIPTION Continue reading... Full patent description for Array of light emitting devices to produce a white light source Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Array of light emitting devices to produce a white light source patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Array of light emitting devices to produce a white light source or other areas of interest. ### Previous Patent Application: Device and method for manufacturing wafer-level package Next Patent Application: Bonding an optical element to a light emitting device Industry Class: Semiconductor device manufacturing: process ### FreshPatents.com Support Thank you for viewing the Array of light emitting devices to produce a white light source patent info. IP-related news and info Results in 5.10886 seconds Other interesting Feshpatents.com categories: Tyco , Unilever , Warner-lambert , 3m |
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