Display device

• US 7,982,812 B2
• Filed: 09/04/2008
• Issued: 07/19/2011
• Est. Priority Date: 10/09/2007
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Rho, Soon-Joon, Jung, Min-Sik, Jeon, Baek-Kyun, Lee, Hee-Keun
• Primary Examiner(s): KIANNI, KAVEH C
• Application Number:
  US12/204,725
• Publication Number:
  US 20090091689A1
• Time in Patent Office: 1,048 Days
• Field of Search: 349/25, 349/30
• US Class Current: 349/25
• CPC Class Codes: C09K 11/54 containing zinc or cadmium
• CPC Class Codes: C09K 11/56 containing sulfur
• CPC Class Codes: C09K 11/565 with zinc cadmium
• CPC Class Codes: C09K 11/62 containing gallium, indium or thallium
• CPC Class Codes: C09K 11/661 Chalcogenides
• CPC Class Codes: C09K 11/70 containing phosphorus
• CPC Class Codes: C09K 11/706 Aluminates; Silicates
• CPC Class Codes: C09K 11/74 containing arsenic, antimony or bismuth
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02F 1/01791 Quantum boxes or quantum dots
• CPC Class Codes: G02F 1/133602 Direct backlight
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133617 Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials
• CPC Class Codes: G02F 2203/34 Colour display without the use of colour mosaic filters

Abstract

In a display device, first and second substrates parallel to each other are arranged between first and second polarizers that are parallel to each other. A liquid crystal layer is arranged between the first and second substrates, and a light emitting layer having a quantum dot structure is arranged on the first polarizer. Also, a light source that emits a blue light is arranged under the second polarizer. Thus, the display device may improve a light utilizing efficiency, thereby improving a display quality.

Claims

1. A display device comprising:

a liquid crystal panel comprising a liquid crystal layer;

a light source disposed under the liquid crystal panel to emit a blue light; and

a light emitting layer disposed on the liquid crystal panel and excited by the blue light exiting through the liquid crystal panel to emit a light having a longer wavelength than the blue light,

wherein the liquid crystal panel comprises a first pixel area, a second pixel area, and a third pixel area,

the light emitting layer comprises a first color light emitting layer, a second color light emitting layer, and a third color light emitting layer that are corresponding to the first, second, and third pixel areas in a one-to-one fashion, and

the first, second, and third color light emitting layers comprise quantum dot phosphors having different quantum dot sizes from each other to emit different color light from each other.

2. The display device of claim 1, wherein each of the quantum dot phosphors comprises a material selected from the group consisting of a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV compound, and a mixture consisting of the compounds.

3. The display device of claim 2, wherein the group II-VI compound comprises a material selected from the groups consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HggZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe.

4. The display device of claim 2, wherein the group III-V compound comprises a material selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb.

5. The display device of claim 2, wherein the group IV-VI compound comprises a material selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, and the group IV compound comprises a material selected from the group consisting of Si, Ge, SiC, and SiGe.

6. The display device of claim 1, further comprising:

a first polarizer disposed on the liquid crystal panel; and

a second polarizer disposed under the liquid crystal panel,

wherein the first polarizer has a polarizing axis substantially perpendicular to a polarizing axis of the second polarizer.

7. The display device of claim 6, wherein the liquid crystal panel is operated in a twisted nematic (TN) mode, a vertical alignment (VA) mode, or an in-plane switching (IPS) mode.

8. The display device of claim 6, wherein the light emitting layer is arranged on the first polarizer and the light source is arranged under the second polarizer.

9. The display device of claim 1, wherein the light source comprises a light emitting diode (LED).

10. The display device of claim 1, wherein the light emitting layer comprises a first light emitting layer, a second light emitting layer, a third light emitting layer that have different colors from each other.

11. The display device of claim 10, wherein the first, second, and third color light emitting layers comprise quantum dot phosphors having different sizes from each other.