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Combination Quantum Dot Film

IP.com Disclosure Number: IPCOM000234817D
Publication Date: 2014-Feb-07
Document File: 6 page(s) / 87K

Publishing Venue

The IP.com Prior Art Database

Related People

William C. Hamburgen: AUTHOR

Abstract

A material containing a concentration of hazardous material that is greater than a threshold concentration that would trigger regulatory review (e.g, a quantum dot optical film that contains cadmium) can be combined with another material to create a product that has a concentration of the hazardous material that is below the threshold.

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Combination Quantum Dot Film

William C. Hamburgen

ABSTRACT

A material containing a concentration of hazardous material that is greater than a threshold concentration that would trigger regulatory review (e.g, a quantum dot optical film that contains cadmium) can be combined with another material to create a product that has a concentration of the hazardous material that is below the threshold.

    Regulations in various jurisdictions limit the amount of hazardous materials that may be included in a product that is offered for sale within the jurisdiction. For example, the European Union Directive 2002/95/EC (a.k.a., the Restriction of Hazardous Materials or RoHS) restricts the use of six hazardous materials found in electrical and electronic products. All applicable products in the EU market must comply with the regulations that limit the content of the following hazardous materials used in a product to the following concentrations: lead content must be less than 1000 ppm; mercury content must be less than 100 ppm; cadmium content must be less than 100 ppm; hexavalent chromium must be less than 1000 ppm; polybrominated biphenyls must be less than 1000 ppm; and polybrominated diphenyl esters must be less than 1000 ppm. See e.g., http://www.rohsguide.com/rohs-substances.htm.

    Some electronic products that use display screens, such as light emitting diode (LED) backlit display screens and liquid crystal displays (LCD), use quantum-dot phosphor films to enhance the output from the display screen. In traditional LED technology, blue LED's are coated with yellow phosphor materials (e.g., the yttrium aluminum garnet (YAG)), which converts some of the blue light into yellow light, and

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the combination of the native blue light and the converted yellow light produces the white light from the backlight.

    Backlights equipped with quantum dot technology operate similarly, in that some native blue light from the blue LED is converted into narrow-spectrum green and red light by the quantum dot material, and the combination of the light emitted from the blue LED and the quantum dot materials produces white light. Because the red and green spectral peaks emitted from quantum dot materials are narrower than the spectral peak of light emitted from traditional phosphor materials, the red, green, and blue peaks from a quantum dot-equipped backlight can align more closely with the spectral transmission peaks of the color filters used in the display. Thus, a quantum dot-equipped backlight can produce more usable light that can be transmitted to a viewer of the display. Because of this, quantum dot technology can be used with efficient blue LEDs and conventional color filters to express a high color gamut display more efficiently than high color gamut displays that use yellow phosphor materials, which typically require energy-intensive LEDs and/or aggressive color filters.

    Displays based on this technology can be used in televisions, mobile phon...