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Luminescent device

a technology of luminescent devices and fluorescent lighting, which is applied in the direction of instruments, fibre light guides, optical elements, etc., can solve the problems of poor spectral quality of fluorescent lighting, low energy efficiency of incandescent lighting, and eye strain and other adverse health effects

Inactive Publication Date: 2010-08-19
RES TRIANGLE INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a device for stimulable light emission that includes a fiber mat made of nanofibers and plural luminescent particles. The nanofibers have an average fiber diameter in a range between 100 and 2000 nm, which provides scattering sites for the primary light. The device can be made by electrospinning a polymer solution containing luminescent particles and collecting the nanofibers to form a fiber mat. The device can also be coated with luminescent particles and used for various applications such as lighting and imaging. The technical effects of the invention include improved light emission and enhanced optical properties of the device.

Problems solved by technology

However, many users complain that the light produced by the existing fluorescent lighting is of poor spectral quality and produces eye strain and other adverse health effects.
However, incandescent lighting suffers from very low energy efficiency.
While this approach produces white light, it suffers from low efficiency and poor spectral quality due to the limited number of wavelengths.
In addition, while the light intensity from current solid-state lights is sufficient for applications such as flashlights, it is considered too low and the emission cone is considered too narrow for use in general illumination applications such as room lighting.
While this method has been successful in producing white light, the three-dimensional dome structure places large quantities of quantum dots in non-optimal positions around the LED and creates potential quantum dot agglomeration issues.
The size range of the nanoparticles and nanofibers disclosed therein is not advantageous for conversion of a primary light into secondary light emission across the white light spectrum.
Once again, the size range of the nanoparticles and nanofibers shown therein is not advantageous for conversion of a primary light into secondary light emission across the white light spectrum.

Method used

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Examples

Experimental program
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Effect test

example 1

Excitation Source: Blue LED at 450-460 nm

[0092]Luminescent compound: a single variety of CdSe / ZnS core shell quantum dots with particle diameter 2.6-3.2 nm (configured for yellow emission and commercially available from Evident Technologies)

[0093]Such yellow emitting quantum dots in this example are incorporated into and onto the fibers at weight percentages between 0.1% and 30% (weight quantum dots / weight fiber) with a more suitable range of weight percentage between 1% and 10% depending upon desired light output.

[0094]When packaged with the blue LED emitting at 450-460 nm, the blue light from the LED and the yellow emission from the photoluminescent fiber in this example blend to produce white light.

example 2

Excitation Source: Blue LED at 450-460 nm

[0095]Luminescent compound: Two different sizes of CdSe / ZnSe core shell quantum dots with the particle diameter of the first size being 2.4 nm (green emission) and the particle diameter of second size being 5.2 nm (red emission) (purchased from Evident Technologies).

[0096]These two sizes of luminescent quantum dots are incorporated into and onto the fibers at weight percentages between 0.1% and 30% (total weight quantum dots / weight fiber) with a more suitable range of weight percentage between 1% and 10%. The ratio of green particles to red particles incorporated into and on the fibers varies between 0.5:1 to 4:1 depending upon desired light output.

[0097]When packaged with a blue LED emitting at 450-460 nm, the blue light from the LED and the green and yellow emission from the photoluminescent fiber in this example blend to produce white light.

example 3

Excitation Source: Violet LED at 408 nm

[0098]Luminescent compound: Two different sizes of CdSe / ZnSe core shell quantum dots with the particle diameter of the first size being 2.4 nm (green emission) and the particle diameter of the second size being 5.2 nm (red emission) (purchased from Evident Technologies).

[0099]These two sizes of luminescent quantum dots are incorporated into and onto the fibers at weight percentages between 0.1% and 30% (total weight quantum dots / weight fiber) with a more suitable range of weight percentage between 1% and 10%. The ratio of green particles to red particles incorporated into and on the fibers varies between 0.5:1 to 5:1 depending upon desired light output.

[0100]When packaged with a violet emitting LED at 408 nm, white light is produced in this example by blending the emission of red and green colors by the photoluminescent nanofiber combined with the violet emission of the LED.

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Abstract

A device for stimulable light emission that includes a fiber mat of nanofibers having an average fiber diameter in a range between 100 and 2000 nm, and includes plural stimulable particles disposed in association with the nanofibers. The stimulable particles produce secondary light emission upon receiving primary light at a wavelength λ. The average fiber diameter is comparable in size to the wavelength λ in order to provide scattering sites within the fiber mat for the primary light. Various methods for making suitable luminescent nanofiber mats include: electrospinning a polymer solution including or not including the stimulable particles and forming from the electrospun solution nanofibers having an average fiber diameter between 100 and 2000 nm. Methods, which electrospin without the stimulable particles, introduce the stimulable particles during electrospinning or after electrospinning to the fibers and therefore to the resultant fiber mat.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a Divisional of application Ser. No. 11 / 559,260, filed Nov. 13, 2006, which is incorporated herein by reference and which is related to U.S. application Ser. No. 10 / 819,916, filed on Apr. 8, 2004, entitled “Electrospinning of Polymer Nanofibers Using a Rotating Spray Head,” Attorney Docket No. 245015US-2025-2025-20, the entire contents of which are incorporated herein by reference. This application is also related to U.S. application Ser. No. 10 / 819,942, filed on Apr. 8, 2004, entitled “Electrospray / electrospinning Apparatus and Method,” Attorney Docket No. 241013US-2025-2025-20, the entire contents of which are incorporated herein by reference. This application is related to U.S. application Ser. No. 10 / 819,945, filed Apr. 8, 2004, entitled “Electrospinning in a Controlled Gaseous Environment,” Attorney Docket No. 245016US-2025-2025-20, the entire contents of which are incorporated herein by reference. This applicatio...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C09K11/02D04H1/413D04H1/42D04H1/4282D04H1/4326D04H1/4382D04H1/728
CPCC09K11/565C09K11/883D01D5/0007D01F11/00D06M11/52H01L33/501H01L2924/0002D04H1/413D04H1/43838H01L2924/00G02B6/0001G02B6/00D04H1/42G02B6/0008
Inventor DAVIS, JAMES LYNNADRADY, ANTHONY L.ENSOR, DAVID S.HAN, LIWALLS, HOWARD J.
Owner RES TRIANGLE INST