Light emitting device package, backlight unit, lighting device and its manufacturing method

• US 9,397,278 B2
• Filed: 11/20/2014
• Issued: 07/19/2016
• Est. Priority Date: 03/05/2014
• Status: Active Grant

• Current Assignee: Lumens Co., Ltd.
• Original Assignee: Lumens Co., Ltd.
• Inventors: Oh, Seunghyun, Lee, Seunghoon, Nam, Tehong, Han, Kangmin
• Primary Examiner(s): Bowman, Mary Ellen
• Application Number:
  US14/434,551
• Publication Number:
  US 20160149103A1
• Time in Patent Office: 607 Days
• US Class Current: 1/1
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02B 6/009 of the light source in the package G02B6/0021 takes precedence
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/04026 Bonding areas specifically adapted for layer connectors
• CPC Class Codes: H01L 2224/05553 being rectangular
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/0615 Mirror array, i.e. array having only a reflection symmetry, i.e. bilateral symmetry
• CPC Class Codes: H01L 2224/10175 Flow barriers
• CPC Class Codes: H01L 2224/1132 Screen printing, i.e. using a stencil
• CPC Class Codes: H01L 2224/131 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/16257 the bump connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/26175 Flow barriers
• CPC Class Codes: H01L 2224/2732 Screen printing, i.e. using a stencil
• CPC Class Codes: H01L 2224/291 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/81192 wherein the bump connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/81385 Shape, e.g. interlocking features
• CPC Class Codes: H01L 2224/81815 Reflow soldering
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83385 Shape, e.g. interlocking features
• CPC Class Codes: H01L 2224/83815 : Reflow soldering
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/16 : of an individual bump connector
• CPC Class Codes: H01L 24/32 : of an individual layer connector
• CPC Class Codes: H01L 24/81 : using a bump connector
• CPC Class Codes: H01L 24/83 : using a layer connector
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2933/0066 : relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/486 : adapted for surface mounting
• CPC Class Codes: H01L 33/54 : having a particular shape
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

Provided are a light emitting device package, a backlight unit, a lighting device and its manufacturing method. The light emitting device package may include a flip chip type light emitting device having a first pad and a second pad, a lead frame that includes a first electrode disposed at one side of an electrode separation space, and a second electrode disposed at the other side of the electrode separation space, and on which the light emitting device is mounted, a first bonding medium formed between the first pad of the light emitting device and the first electrode of the lead frame to electrically connect the first pad and the first electrode, and a second bonding medium formed between the second pad of the light emitting device and the second electrode of the lead frame to electrically connect the second pad and the second electrode, wherein at least one first accommodating cup capable of accommodating the first bonding medium is formed in the first electrode of the lead frame, wherein at least one second accommodating cup capable of accommodating the second bonding medium is formed in the second electrode of the lead frame, and wherein at least one air discharge path is formed on each of the first and second accommodating cups.

Claims

1. A light emitting device package comprising:

a flip chip type light emitting device having a first pad and a second pad;

a lead frame that comprises a first electrode disposed at one side of an electrode separation space and a second electrode disposed at the other side of the electrode separation space, and on which the light emitting device is mounted;

a first bonding medium disposed between the first pad of the light emitting device and the first electrode of the lead frame to electrically connect the first pad and the first electrode; and

a second bonding medium disposed between the second pad of the light emitting device and the second electrode of the lead frame to electrically connect the second pad and the second electrode,

wherein at least one first accommodating cup capable of accommodating the first bonding medium is formed in the first electrode of the lead frame,

wherein at least one second accommodating cup capable of accommodating the second bonding medium is formed in the second electrode of the lead frame, and

wherein at least one air discharge path is formed on each of the first and second accommodating cups to easily discharge the air inside the first and second accommodating cups to the outside due to the first and second bonding media depressed inside the first and second accommodating cups when the light emitting device is mounted on the lead frame.

2. The light emitting device package of claim 1,

wherein the first and second accommodating cups are located within a chip footprint area of the light emitting device or pad footprint areas of the first and second pads, and

wherein the air discharge path extends from inside of the chip footprint area or the pad footprint areas to the outside of the chip footprint area or the pad footprint areas.

3. The light emitting device package of claim 1,

wherein the air discharge path is a groove connected to the first accommodating cup and/or the second accommodating cup and having an open top surface, and is selected from the group consisting of a rectangular groove having a rectangular cross section, an inclined groove having an inclined surface, a polygonal groove having a polygonal cross section, and a round groove having a partially round cross section.

4. The light emitting device package of claim 1,

wherein a step is formed on the air discharge path to prevent discharge of the first or second bonding medium through the air discharge path.

5. The light emitting device package of claim 1,

wherein an air vent width of the air discharge path is greater than a particle size of the first or second bonding medium to allow partial discharge of the first or second bonding medium through the air discharge path.

6. The light emitting device package of claim 1,

wherein each of the first and second accommodating cups has an inclined bottom surface or a bottom protrusion to guide the first and second bonding media toward the air discharge path.

7. The light emitting device package of claim 1,

wherein the first and second bonding media are made of solder paste coated or dispensed on the first and second accommodating cups, respectively,

wherein a plurality of first accommodating cups are located in parallel along a length or width direction of the first pad, and

wherein the light emitting device package further comprises a reflective encapsulant that fills the electrode separation space to form an electrode separation wall and that forms a reflective cup surrounding side surfaces of the light emitting device.

8. A backlight unit comprising:

a flip chip type light emitting device having a first pad and a second pad;

a lead frame that comprises a first electrode disposed at one side of an electrode separation space and a second electrode disposed at the other side of the electrode separation space, and on which the light emitting device is mounted;

a first bonding medium disposed between the first pad of the light emitting device and the first electrode of the lead frame to electrically connect the first pad and the first electrode;

a second bonding medium disposed between the second pad of the light emitting device and the second electrode of the lead frame to electrically connect the second pad and the second electrode; and

a light guide plate formed on an optical path of the light emitting device,

wherein at least one first accommodating cup capable of accommodating the first bonding medium is formed in the first electrode of the lead frame,

wherein at least one second accommodating cup capable of accommodating the second bonding medium is formed in the second electrode of the lead frame, and

wherein at least one air discharge path is formed on each of the first and second accommodating cups to easily discharge the air inside the first and second accommodating cups to the outside due to the first and second bonding media depressed inside the first and second accommodating cups when the light emitting device is mounted on the lead frame.

9. A lighting device comprising:

a flip chip type light emitting device having a first pad and a second pad;

a lead frame comprising a first electrode disposed at one side of an electrode separation space, and a second electrode disposed at the other side of electrode separation space;

a first bonding medium disposed between the first pad of the light emitting device and the first electrode of the lead frame to electrically connect the first pad and the first electrode; and

a second bonding medium disposed between the second pad of the light emitting device and the second electrode of the lead frame to electrically connect the second pad and the second electrode,

wherein at least one first accommodating cup capable of accommodating the first bonding medium is formed in the first electrode of the lead frame,

wherein at least one second accommodating cup capable of accommodating the second bonding medium is formed in the second electrode of the lead frame, and

wherein at least one air discharge path is formed on each of the first and second accommodating cups to easily discharge the air inside the first and second accommodating cups to the outside due to the first and second bonding media depressed inside the first and second accommodating cups when the light emitting device is mounted on the lead frame.