Photo-luminescent liquid crystal display

• US 20060274226A1
• Filed: 06/01/2006
• Published: 12/07/2006
• Est. Priority Date: 06/02/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Byung-ki, Choi, Jae-young, Im, Seoung-jae
• Granted Patent: US 7,746,423 B2
• Time in Patent Office: Days
• US Class Current: 349/71
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02F 1/133617 Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
• CPC Class Codes: G02F 2201/086 UV absorbing
• CPC Class Codes: G02F 2202/106 Cd×Se or Cd×Te and alloys
• CPC Class Codes: G02F 2202/108 quantum wells
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials

Abstract

A photo-luminescent (PL) liquid crystal display (LCD) including a blue dichroic mirror layer disposed under a light emitting layer is provided. Visible light generated from the light emitting layer is mostly reflected to the front side of the PL LCD, thereby increasing the light utilization efficiency thereof. A blue PL quantum dot layer is formed in blue light regions, thereby improving a narrow viewing angle and an orientation in blue pixels. An ultraviolet (UV) filter blocking UV light in the ambient light is formed to protect the light emitting layer from the excitation caused by external light, thereby preventing degradation of contrast caused by an undesired light emission.

Claims

1. A photo-luminescent (PL) liquid crystal display (LCD), comprising:

a backlight unit generating blue light;

a liquid crystal layer defining a plurality of red, green, and blue pixels and switching blue light from the backlight unit to control the passage of the blue light through the pixels defined for each color and a liquid crystal driving unit driving the liquid crystals;

a light emitting layer respectively corresponding to the each pixel; and

a blue dichroic mirror layer which is disposed between the light emitting layers and the backlight unit, and which transmits blue light from the backlight unit.

2. The PC LCD of claim 1, wherein a portion of the light emitting layer corresponding to the blue pixels comprises quantum dots.

3. The PC LCD of claim 2, wherein the quantum dots are formed of Il-IV or III-V compounds.

4. The PC LCD of claim 1, wherein a red phosphor layer in the light emitting layer is selected from the group consisting of (Sr,CaS):

Eu²⁺, (Sr,Ca)₂Si₅N₈;

Eu²⁺, and Mg₄GeO 5.5 F;

Mn⁴⁺,

wherein a green phosphor layer in the light emitting layer is selected from the group consisting of SrGa₂S₄;

Eu²⁺, (Ba,Sr)SiO₄;

Eu²⁺, MgSi₂O₇, SrAI₂O₄;

Eu²⁺, Ca₈Mg(SiO₄₄CI₂;

Eu²⁺, and (Cr,Ca)(Al,Si)²;

Eu²⁺.

5. The PC LCD of claim 2, wherein a red phosphor layer in the light emitting layer is selected from the group consisting of (Sr,CaS):

Eu²⁺, (Sr,Ca)₂Si₅N₈;

Eu²⁺, and Mg₄GeO 5.5 F;

Mn⁴⁺,

wherein a green phosphor layer in the light emitting layer is selected from the group consisting of SrGa₂S₄;

Eu²⁺, (Ba,Sr)SiO₄;

Eu²⁺, MgSi₂O₇, SrAl₂O₄;

Eu²⁺, Ca₈Mg(SiO₄₄Cl₂;

Eu²⁺, and (Cr,Ca)(Al,Si)²;

Eu²⁺.

6. The PC LCD of claim 4, further comprising an ultraviolet (UV) filter for blocking external UV light and preventing absorption of UV light into the light emitting layer.

7. The PC LCD of claim 5, further comprising an ultraviolet (UV) filter for blocking external UV light and preventing absorption of UV light into the light emitting layer.

8. The PC LCD of claim 6, wherein the UV filter is selected from the group consisting of para-aminobenzoic acid (PABA) derivatives, cinnamate-derivatives, salicylic acid derivatives, benzophenone and its derivatives, and antharanilate and its derivatives.

9. The PC LCD of claim 7, wherein the UV filter is selected from the group consisting of para-aminobenzoic acid (PABA) derivatives, cinnamate-derivatives, salicylic acid derivatives, benzophenone and its derivatives, and antharanilate and its derivatives.

10. The PC LCD of claim 6, wherein the UV filter is selected from the group consisting of zinc oxide, titanium dioxide, iron oxide, and magnesium oxide.

11. The PC LCD of claim 1, further comprising a UV filter blocking external UV light and preventing absorption of UV light into the light emitting layers.

12. The PC LCD of claim 2, further comprising a UV filter blocking external UV light and preventing absorption of UV light into the light emitting layers.

13. The PC LCD of claim 3, further comprising a UV filter blocking external UV light and preventing absorption of UV light into the light emitting layers.

14. The PC LCD of claim 11, wherein the UV filter is selected from the group consisting of para-aminobenzoic acid (PABA) derivatives, cinnamate derivatives, salicylic acid derivatives, benzophenone and its derivatives, and antharanilate and its derivatives.

15. The PC LCD of claim 11, wherein the UV filter is selected from the group consisting of zinc oxide, titanium dioxide, iron oxide, and magnesium oxide.