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White LED for backlight with phosphor plates

  • US 7,682,850 B2
  • Filed: 03/17/2006
  • Issued: 03/23/2010
  • Est. Priority Date: 03/17/2006
  • Status: Active Grant
First Claim
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1. A method of forming a light emitting device comprising:

  • testing LED dies that emit light with a peak wavelength less than approximately 480 nm and determining light emission characteristics of the LED dies;

    binning the LED dies in accordance with their light emission characteristics;

    forming a variety of plates of a phosphor that emit at least orange-red or red light with a peak wavelength larger than 590 nm when energized by light from the LED dies, the plates being formed separate from the LED dies, the plates having different characteristics associated with different bins of LED dies;

    matching a plate having a particular characteristic to a binned LED die to generate a white light having a target white point;

    affixing a matched plate over an LED die to form a white light LED emitting orange-red or red, green or yellow-green, and blue light components, wherein a combination of the orange-red or red, green or yellow-green, and blue light components produces white light having the target white point; and

    mounting at least one said white light LED in an illumination module for a pixelated light modulator, the modulator controlling at least red, green, and blue color subpixels, wherein the plates are matched to the binned LED dies to generate orange-red or red and blue light components whose peak wavelengths are within approximately 10% of the wavelengths corresponding to maximum light output requirements of the red and blue subpixels within a certain range of wavelengths.

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