Method of LED light engine assembly

Patent metadata

Field	Value
Publication number	US-10895353-B2
Application number	US-201916729175-A
Country	US
Kind code	B2
Filing date	Dec 27, 2019
Priority date	Apr 23, 2019
Publication date	Jan 19, 2021
Grant date	Jan 19, 2021

Abstract

A lighting engine, system and method of fabrication are described. The system contains a flexible printed circuit (FPC) shaped as a loop. LEDs are mounted on the FPC to emit light toward a center of the loop. A light guide positioned in an interior of the loop receives light emitted by the LEDs through an edge of the light guide. The light guide has slots formed therein that receive locator pins to limit thermal displacement of the light guide towards the LEDs. Other apparatuses, systems, and methods are also disclosed.

First claim

What is claimed is:

1. A method of assembling a lighting system, the method comprising:
determining whether a chassis has mechanical defects outside of a predetermined nominal range of defect;
removing residue on the chassis in response to determining that the reflector has no mechanical defects outside of the predetermined nominal range of defect;
installing a gasket in a groove of the chassis after determining whether the chassis has mechanical defects outside of the predetermined nominal range of defect;
mounting light emitting diode (LED) strips on the chassis to form a first integrated chassis;
inserting locator pins into the chassis between LEDs of the LED strips;
aligning a light guide plate (LGP) with the locator pins in the chassis; and
placing the LGP aligned in the chassis such that the LGP in the chassis is retained by the locator pins to limit thermal displacement of the LGP towards the LEDs.

2. The method of claim 1 , further comprising:
integrating a reflector in the chassis containing the LGP to form a second integrated chassis, the reflector integrated in the second integrated chassis to cover the LGP substantially entirely and reflect light emitted by the LEDs into the LGP toward an exit surface of the LGP.

3. The method of claim 2 , further comprising:
installing a strain relief mechanism to an outer portion of the second integrated chassis; and
applying a protective film to the exit surface of the LGP in the second integrated chassis.

4. The method of claim 1 , further comprising:
in further response to determining that the reflector has no mechanical defects outside of the predetermined nominal range of defect, applying a protective film to an edge of the reflector prior to integrating the reflector in the chassis.

5. The method of claim 4 , further comprising:
in further response to determining that the backplate has no mechanical defects outside of the predetermined nominal range of defect, sealing the first integrated chassis using the backplate and the gasket during formation of the second integrated chassis, the gasket contacting the exit surface of the LGP;
removing residue on the backplate to form a clean backplate; and
attaching a spacer to the clean backplate to separate the backplate and the reflector.

6. The method of claim 5 , further comprising:
providing a white reflective sheet between the reflector and the backplate, the white reflective sheet having a diameter larger than that of the reflector.

7. The method of claim 5 , further comprising:
inserting a reflective material between the reflector and the LED strips.

8. The method of claim 5 , further comprising:
attaching a reflective tape between the reflector and the LED strips, over an edge of the reflector, and between the reflector and the backplate, the reflective tape attached to the LGP, the edge of the reflector, and a surface of the reflector opposing the backplate.

9. The method of claim 8 , further comprising:
inserting a secondary reflective material on the reflective tape on the LGP and between the reflective tape and the LED strips.

10. The method of claim 1 , further comprising:
determining whether the LGP is substantially free from Moiré fringes by performing at least one action selected from a set of actions comprising:
measuring light emitted from the LGP, and
capturing light emitted from the LGP and visually inspecting the LGP using the captured light.

11. The method of claim 1 , further comprising mounting LED strips on the chassis by:
attaching a flexible printed circuit (FPC) containing the LED strips to an inner wall of a ridge that forms a cavity in the chassis;
bending a leg of the FPC over a top of the ridge to an outer wall on an opposite side of the ridge as the inner wall; and
making electrical contact with the FPC to drive the LEDs.

12. A method of assembling a lighting system, the method comprising:
integrating light emitting diode (LED) strips on a flexible printed circuit board (FPC) with a chassis to form a first integrated chassis;
inserting a light guide plate (LGP) into the first integrated chassis;
illuminating the LED strips to determine whether at least one of optical and mechanical defects are present in a first surface of the LGP;
determining whether optical and mechanical defects outside of a predetermined nominal range of defect are present in the first surface of the LGP;
based on a determination that neither optical nor mechanical defects outside of the predetermined nominal range of defects are determined to be present in the first surface of the LGP, installing a reflector on the first surface of the LGP to form a second integrated chassis, the reflector installed to reflect light emitted by the LEDs into the LGP toward a second surface of the LGP opposing the first surface of the LGP; and
determining whether Moiré fringes are present in the second surface of the LGP by varying a position of the second integrated chassis.

13. The method of claim 12 , further comprising:
checking diameters of pin holes in the chassis;
inserting locator pins in the pin holes based on a determination that the pin holes are correctly sized for the locator pins; and
inserting the LGP into the first integrated chassis by aligning the LGP with the locator pins and inserting the aligned LGP into the first integrated chassis.

14. The method of claim 13 , further comprising:
supplying power to the LED strips prior to integrating the FPC in the chassis to determine whether the LEDs on each LED strip illuminate;
in response to a determination that the LEDs illuminate, cleaning the FPC to be laminated on the chassis;
progressively peeling a pressure sensitive adhesive (PSA) release film on a back of the FPC;
aligning an end of the FPC with one of the pin holes to ensure that no locator pin, when inserted into the chassis, will block any of the LEDs; and
aligning a bottom edge of the FPC with a trench floor of the chassis such that the bottom edge is coincident with the trench floor the length of the FPC; and
applying pressure against flat surfaces of the FPC between the LEDs as the PSA release film is peeled off until an entirety of the FPC is mounted on the chassis, and thereafter inserting the locator pins in the pin holes.

15. The method of claim 14 , further comprising:
connecting different color wires that supply power to the FPC to the LED strips by, for each color:
locating a wire having the color for connection into a first location of a connector on the FPC using a wire location template,
retaining an end of the wire having the color, inserting the end of the wire into the first location, and ensuring that the wire having the color is securely connected thereafter; and
routing the wires through a channel formed by a cavity in the chassis using tape to hold the wires in place.

16. The method of claim 15 , further comprising:
removing residue on the chassis based on the determination that the chassis has no mechanical defects outside of the predetermined nominal range of defect; and
installing a gasket in a groove of the chassis.

17. The method of claim 16 , further comprising:
rolling back protective film from a portion of an edge of the reflector after the determination that no mechanical defects are present in the reflector;
applying tape to the portion of the edge of the reflector that is uncovered by the protective film to form tape-covered edge; and
smoothing back the protective film on the tape-covered edge of the reflector and continuing to roll back the protective film, apply t

Assignees

• Lumileds Holding Bv
• Lumileds Llc

Inventors

• Diana Frederic Stephane
• Teoh Seng-Hup
• Wasilko Michael

Classifications

• H10H29/14

  comprising multiple light-emitting semiconductor components · CPC title

• H10H20/857

  Interconnections, e.g. lead-frames, bond wires or solder balls · CPC title

• G02B6/0085

  Means for removing heat created by the light source from the package · CPC title

• H05K1/147

  at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit (H05K1/148 takes precedence) · CPC title

• H05K1/0274

  Optical details, e.g. printed circuits comprising integral optical means (H05K1/0269 takes precedence; coupling light guides with opto-electronic components G02B6/42) · CPC title