SEGMENTED BACKLIGHT STRUCTURE WITH IN-COUPLING STRUCTURES

• US 20190324191A1
• Filed: 04/17/2019
• Published: 10/24/2019
• Est. Priority Date: 04/18/2018
• Status: Abandoned Application

• Current Assignee: Lumileds Holding B.V. (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Holding B.V. (Apollo Global Management, Inc.)
• Inventors: CROMPVOETS, Floris Maria Hermansz, FANCSALI, Erno
• Application Number:
  US16/387,168
• Publication Number:
  US 20190324191A1
• Time in Patent Office: Days
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: H01L 27/156 two-dimensional arrays

Abstract

An LED backlight system having a plurality of backlight segments including an integral light waveguide, each backlight segment supporting a sidelight emitting LED. A light guide can have a rectangular shape, a flat top surface, and a curved lower surface that defines a cavity having a top and sidewalls, with the sidelight emitting LED positioned in the cavity. The cavity sidewalls can include light in-coupling structures such as prisms. In one embodiment, each sidelight emitting LED can be rotated with respect to a rectangular cavity, with edges of the sidelight emitting LED facing corners of rectangular cavity. At least one of a reflective layer and a top out-coupling structure can be positioned between the top of the cavity and the sidelight emitting LED.

Claims

1. A LED backlight system, comprising:

a plurality of backlight segments, each backlight segment supporting a sidelight emitting LED;

a light guide segment included in each backlight segment, with the light guide having a rectangular shape and a flat top surface, the light guide further defining a cavity having a top and sidewalls, with the sidelight emitting LED positionable in the cavity; and

a sidewall in-coupling structure is positioned between the sidewalls of the cavity and the sidelight emitting LED, and

wherein each sidelight emitting LED is centrally positioned in the respective backlight segment.

2. The LED backlight system of claim 1, wherein each sidelight emitting LED is rotated with respect to a rectangular cavity, with edges of the sidelight emitting LED facing corners of rectangular cavity.

3. The LED backlight system of claim 1, wherein the sidewall in-coupling structure are prisms defined on the cavity sidewall.

4. The LED backlight system of claim 1, wherein the backlight segments are separated from each other by an optical barrier.

5. The LED backlight system of claim 4, wherein the optical barrier separating the backlight segments from each other is defined in part by a tapered edge of the light guide segment.

6. The LED backlight system of claim 4, wherein the optical barrier separating the backlight segments from each other is at least one of a reflective and absorptive coating.

7. The LED backlight system of claim 1, wherein at least one of a reflective layer and a top out-coupling structure are positioned between the top of the cavity in the light guide and the sidelight emitting LED.

8. The LED backlight system of claim 1, wherein the light guide has a curved lower surface.

9. The LED backlight system of claim 8, wherein the light guide includes a smooth lower surface terminating in edges that have a lesser height at corners as compared to centers of respective edges.