Light-emitting device package and electronic device including light-emitting device

Patent metadata

Field	Value
Publication number	US-9681509-B2
Application number	US-201514969191-A
Country	US
Kind code	B2
Filing date	Dec 15, 2015
Priority date	Mar 6, 2015
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A light-emitting device package includes a substrate; a light-emitting device provided on the substrate and configured to be driven by an AC power supply; and a capacitor connected in series with the light-emitting device, where a capacitance of the capacitor varies so that a current flowing through the light-emitting device and flowing through the capacitor is maintained at a constant value according to a variation in temperatures of the light-emitting device and the capacitor.

First claim

What is claimed is:

1. A light-emitting device package comprising:
a substrate;
a light-emitting device provided on the substrate and configured to be driven by an AC power supply; and
a capacitor connected in series with the light-emitting device, the capacitor comprising a dielectric formed of a material different from a material of the substrate and a first plate contacting a surface of the light-emitting device;
wherein a capacitance of the capacitor varies according to a variation in temperatures of the light-emitting device and the capacitor, so that a current flowing through the light-emitting device and flowing through the capacitor is maintained at a constant value; and
wherein a width of the dielectric is less than a width of the light-emitting device, the width of the dielectric and the width of the light-emitting device being parallel to the surface of the light-emitting device.

2. The light-emitting device package of claim 1 , wherein a variation in the capacitance of the capacitor for a charging time t c of the capacitor satisfies the following formula:

Δ
⁢

⁢
C

=

[

C
2

⁢
Δ
⁢

⁢

V
⁡

(

t
c

)

C
⁢

⁢
Δ
⁢

⁢

V
⁡

(

t
c

)

+

I
0

⁢

t
c

]

where I 0 is the current that flows through the light-emitting device and flows through the capacitor and is measured at an initial temperature T 0 , C is an initial capacitance of the capacitor, ΔV(t c ) is a variation in a voltage of the light-emitting device, and t c is the charging time of the capacitor.

3. The light-emitting device package of claim 1 , wherein the capacitor further comprises a second plate, the dielectric is provided between the first plate and the second plate, and in order for the capacitor to vary so that the current flowing through the light-emitting device and flowing through the capacitor is maintained at the constant value, a cross-sectional area S of the capacitor, a distance d between the first plate and the second plate, and a variation

ⅆ

ɛ
T

ⅆ
T

in a dielectric constant of the dielectric with respect to temperature are determined based on the following formula:

Δ
⁢

⁢
C

=

ⅆ
C

ⅆ
T

=

(

ɛ
0

⁢

S
D

)

⁢

ⅆ

ɛ
r

ⅆ
T

where ∈ 0 is a permittivity in free space and ∈ r is a relative permittivity.

4. The light-emitting device package of claim 1 , wherein
the dielectric penetrates the substrate;
the first plate contacts a top surface of the dielectric; and
the capacitor further comprises a second plate that contacts a bottom surface of the dielectric.

5. The light-emitting device package of claim 4 , wherein the light-emitting device is provided on the first plate to overlap the dielectric in a direction perpendicular to a surface of the light-emitting device.

6. The light-emitting device package of claim 5 , wherein an overlapping cross-sectional area of the light-emitting device and the dielectric is substantially equal to a cross-sectional area of the dielectric.

7. The light-emitting device package of claim 5 , wherein
the light-emitting device is of a plurality of light-emitting devices,
the capacitor is of a plurality of capacitors,
the plurality of capacitors comprises a plurality of dielectrics that penetrate the substrate, and a plurality of first plates that respectively come into contact with top surfaces of the plurality of dielectrics, and
the plurality of light-emitting devices are respectively provided on the plurality of first plates so as to overlap the plurality of dielectrics.

8. The light-emitting device package of claim 7 , wherein the plurality of capacitors are connected in parallel to one another.

9. The light-emitting device package of claim 4 , wherein the light-emitting device is of a plurality of light-emitting devices, and
one of the plurality of light-emitting devices is provided on the first plate so as to overlap the dielectric in a direction perpendicular to a surface of the light-emitting device.

10. The light-emitting device package of claim 1 , wherein the light-emitting device package is configured to control a direction of a driving current flowing through the light-emitting device independently from using an LED driver.

11. The light-emitting device package of claim 1 , wherein the light-emitting device is thermally coupled to the capacitor.

12. The light-emitt

Assignees

• Samsung Electronics Co Ltd

Inventors

• Park In-Soo

Classifications

• H10W90/754

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W90/10

  Configurations of laterally-adjacent chips · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• H10W72/853

  On the same surface · CPC title

• H10W90/00 Primary

  Package configurations · CPC title