Light excitation-diffusion sheet for backlight unit and backlight unit for liquid crystal display using the same

• US 20060109682A1
• Filed: 12/30/2004
• Published: 05/25/2006
• Est. Priority Date: 11/22/2004
• Status: Abandoned Application

• Current Assignee: Koditech Company Limited
• Original Assignee: Koditech Company Limited
• Inventors: Ko, Youngwook, Ahn, Youngju, Lee, Namheon
• Application Number:
  US11/027,119
• Publication Number:
  US 20060109682A1
• Time in Patent Office: Days
• US Class Current: 362/607
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer

Abstract

A light excitation diffusion sheet for a backlight unit adapted to absorb a portion of light emitted from a light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one other wavelength, to emit light at different wavelengths from the light emitted from the light source, and to allow the rest of the light emitted from the light source to penetrate the sheet The light excitation-diffusion sheet comprises a light-exciting material exciting and amplifying the light from the light source and a light-diffusing material scattering and diffusing the light from the light source. The light-exciting material and the light-diffusing material are uniformly distributed in the light excitation-diffusion sheet The use of the light excitation-diffusion sheet enables production of edge light type and direct light type backlight units having diffusion and prism functions, good color purity and improved light efficiency at reduced costs.

Claims

1. A light excitation-diffusion sheet for a backlight unit adapted to absorb a portion of light emitted from a light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength, to emit light at different wavelengths from the light emitted from the light source, and to allow the rest of the light emitted from the light source to penetrate the sheet,

wherein the light excitation-diffusion sheet comprises a light-exciting material exciting and amplifying the light emitted from the light source, and a light-diffusing material scattering and diffusing the light emitted from the light source, the light-exciting material and the light-diffusing material being uniformly distributed in the light excitation-diffusion sheet.

2. A backlight unit for a liquid crystal display, comprising:

an edge light type light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a light guide sheet for guiding light emitted from the light source;

a reflection sheet disposed under the light guide sheet;

a light excitation-diffusion sheet disposed on the light guide sheet;

two prism sheets disposed on the light excitation-diffusion sheet in directions perpendicular and parallel to the light excitation-diffusion sheet, respectively; and

a protective sheet disposed on the prism sheets,

wherein the light excitation-diffusion sheet is adapted to absorb a portion of light emitted from the light source, to emit light at different wavelengths from the light emitted from the light source and to allow the rest of the light emitted from the light source to penetrate the sheet, and the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light source with a light-diffusing material scattering and diffusing the light emitted from the light source.

3. A backlight unit for a liquid crystal display, comprising:

an edge light type light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a light excitation-diffusion sheet adapted to guide light emitted from the light source, to absorb a portion of the guided light, to emit light at different wavelengths from the light emitted from the light source, and to allow the rest of the light emitted from the light source to penetrate the sheet;

two prism sheets disposed on the light excitation-diffusion sheet in directions perpendicular and parallel to the light excitation-diffusion sheet, respectively; and

a protective sheet disposed on the prism sheets,

wherein the light excitation-diffusion sheet includes a light guide part having a bottom surface inclined upwardly toward a side opposed to the light source, and a part formed on the light guide part and packed with a light-exciting material exciting and amplifying the light emitted from the light source and a light-diffusing material scattering and diffusing the light emitted from the light source.

4. A backlight unit for a liquid crystal display, comprising:

an edge light type light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a light guide sheet for guiding light emitted from the light source;

a reflection sheet disposed under the light guide sheet;

a light excitation-diffusion sheet disposed on the light guide sheet;

a prism sheet disposed on the light excitation-diffusion sheet in a direction perpendicular to the light excitation-diffusion sheet; and

a protective sheet disposed on the prism sheet,

wherein the light excitation-diffusion sheet is adapted to absorb a portion of light emitted from the light source, to emit light at different wavelengths from the light emitted from the light source and to allow the rest of the light emitted from the light source to penetrate the sheet, the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light source with a light-diffusing material scattering and diffusing the light emitted from the light source, and the light excitation-diffusion sheet has an upper surface in the shape of a sawtooth facing the prism sheet.

5. A backlight unit for a liquid crystal display, comprising:

an edge light type light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a light excitation-diffusion sheet adapted to guide light emitted from the light source, to absorb a portion of the guided light, to emit light at different wavelengths from the light emitted from the light source, and to allow the rest of the light emitted from the light source to penetrate the sheet;

a prism sheet disposed on the light excitation-diffusion sheet in a direction perpendicular to the light excitation-diffusion sheet; and

a protective sheet disposed on the prism sheet,

wherein the light excitation-diffusion sheet includes a light guide part having a bottom surface inclined upwardly toward a side opposed to the light source, and a part formed on the light guide part and packed with a light-exciting material exciting and amplifying the light emitted from the light source and a light-diffusing material scattering and diffusing the light emitted from the light source; and

the light excitation-diffusion sheet has an upper surface in the shape of a sawtooth facing the prism sheet

6. A backlight unit for a liquid crystal display, comprising:

a plurality of direct light type light sources of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a reflection sheet disposed below the light sources;

a light excitation-diffusion sheet disposed over the light sources;

two prism sheets disposed on the light excitation-diffusion sheet in directions perpendicular and parallel to the light excitation-diffusion sheet, respectively; and

a protective sheet disposed on the prism sheets,

wherein the light excitation-diffusion sheet is adapted to absorb a portion of light emitted from the light sources, to emit light at different wavelengths from the light emitted from the light sources and to allow the rest of the light emitted from the light sources to penetrate the sheet, and the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light sources with a light diffusing material scattering and diffusing the light emitted from the light sources.

7. A backlight unit for a liquid crystal display, comprising:

a plurality of direct light type light sources of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a reflection sheet disposed below the light sources;

a light excitation-diffusion sheet disposed over the light sources;

a prism sheet disposed on the light excitation-diffusion sheet in a direction perpendicular to the light excitation-diffusion sheet; and

a protective sheet disposed on the prism sheet,

wherein the light excitation-diffusion sheet is adapted to absorb a portion of light emitted from the light sources, to emit light at different wavelengths from the light emitted from the light sources and to allow the rest of the light emitted from the light sources to penetrate the sheet, the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light sources with a light-diffusing material scattering and diffusing the light emitted from the light sources, and the light excitation-diffusion sheet has an upper surface in the shape of a sawtooth facing the prism sheet.

8. A bi-directional backlight unit for a liquid crystal display, comprising:

an edge light type light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a light guide sheet for guiding light emitted from the light source; and

light excitation-diffusion sheets, pairs of horizontal and vertical prism sheets, and protective sheets symmetrically layered in this order on the upper surface and lower surface of the light guide sheet, respectively,

wherein each of the light excitation-diffusion sheets is adapted to absorb a portion of light emitted from the light source, to emit light at different wavelengths from the light emitted from the light source and to allow the rest of the light emitted from the light source to penetrate the sheet, and the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light source with a light-diffusing material scattering and diffusing the light emitted from the light source.

9. A bi-directional backlight unit for a liquid crystal display, comprising:

an edge light type light source of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength;

a light guide sheet for guiding light emitted from the light source; and

light excitation-diffusion sheets, vertical prism sheets, and protective sheets symmetrically layered in this order on the upper surface and lower surface of the light guide sheet, respectively,

wherein each of the light excitation-diffusion sheets is adapted to absorb a portion of light emitted from the light source, to emit light at different wavelengths from the light emitted from the light source and to allow the rest of the light emitted from the light source to penetrate the sheet, the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light source with a light-diffusing material scattering and diffusing the light emitted from the light source, and the light excitation-diffusion sheet has an upper surface in the shape of a sawtooth facing the prism sheet

10. A bidirectional backlight unit for a liquid crystal display, comprising:

a plurality of direct light type light sources of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength; and

light excitation-diffusion sheets, pairs of horizontal and vertical prism sheets, and protective sheets symmetrically layered in this order over and under the light sources, respectively,

wherein each of the light excitation-diffusion sheet is adapted to absorb a portion of light emitted from the light sources, to emit light at different wavelengths from the light emitted from the light sources and to allow the rest of the light emitted from the light sources to penetrate the sheet, and the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light sources with a light-diffusing material scattering and diffusing the light emitted from the light sources.

11. A bi-directional backlight unit for a liquid crystal display, comprising:

a plurality of direct light type light sources of a blue wavelength or a mixed wavelength of a blue wavelength and at least one wavelength other than the blue wavelength; and

light excitation-diffusion sheets, vertical prism sheets, and protective sheets symmetrically layered in this order over and under the light sources, respectively,

wherein each of the light excitation-diffusion sheets is adapted to absorb a portion of light emitted from the light sources, to emit light at different wavelengths from the light emitted from the light sources and to allow the rest of the light emitted from the light sources to penetrate the sheet, the light excitation-diffusion sheet is produced by uniformly mixing a light-exciting material exciting and amplifying the light emitted from the light sources with a light-diffusing material scattering and diffusing the light emitted from the light sources, and the light excitation-diffusion sheet has an upper surface in the shape of a sawtooth facing the prism sheet.