LIGHT-EMITTING DEVICE AND METHOD FOR PRODUCING SAME
There is provided a light emitting device highly resistant to the environment, and having good heat resistance, light resistance and gas barrier property, and a method for producing same. With the light emitting device, a substrate 2 and interconnect patterns 5 A, 5 B formed on the surface thereof are covered with an acrylic resin primer 10 having better gas barrier property than a silicone resin sealing resin part 3. Light resistance is ensured by the silicone resin sealing resin portion 3 and the gas barrier property can be ensured by the acrylic resin primer 10.
1 . A light emitting device comprising:
a substrate;
a metal portion formed on a surface of the substrate;
an LED chip mounted on the substrate;
a primer made of resin which covers at least part of the metal portion; and
a sealing resin portion which covers the LED chip and at least part of the primer to seal the LED chip, wherein
the primer is made from a resin which is higher in gas barrier property than the sealing resin portion.
2 . The light emitting device as claimed in claim 1 , wherein
the primer is formed into a layer shape.
3 . The light emitting device as claimed in claim 1 , wherein
the primer is made from an acrylic resin.
4 . The light emitting device as claimed in claim 1 , wherein
the metal portion includes an interconnect pattern.
5 . The light emitting device as claimed in claim 1 , wherein
the metal portion includes a lead frame.
6 . The light emitting device as claimed in claim 1 , wherein
the metal portion includes a metal reflection coating.
7 . The light emitting device as claimed in claim 4 , wherein
a surface of the metal portion is made from Ag, or AgBi-based alloy, or AgNd-based alloy, or an Ag alloy containing 0.5 to 5.0 wt % of at least one kind of metal selected from Pt, Au, Cu, Pd, Mg, Ti and Ta.
8 . The light emitting device as claimed in claim 1 , wherein
the substrate is made from any one of a light-reflective resin, metal and ceramic.
9 . The light emitting device as claimed in claim 1 , wherein
at least a top face of the LED chip is exposed from the primer made of resin.
10 . The light emitting device as claimed in claim 1 , wherein
the LED chip has its top face and side face coated with the primer made of resin.
11 . The light emitting device as claimed in claim 1 , wherein
the primer covers a top face of the substrate.
12 . The light emitting device as claimed in claim 1 , wherein
the primer covers an entire surface of the substrate.
13 . The light emitting device as claimed in claim 1 , wherein
the primer covers a top face of the substrate, and the LED chip is mounted on the primer covering the top face of the substrate.
14 . The light emitting device as claimed in claim 6 , wherein
the metal reflection coating is formed on the substrate,
the primer is formed on the metal reflection coating, and
the interconnect pattern is formed on the primer.
15 . The light emitting device as claimed in claim 1 , wherein
the primer has a thickness of 0.01 μm to 100 μm.
16 . The light emitting device as claimed in claim 1 , wherein
the sealing resin portion is in close contact with a surface of at least part of the primer.
17 . The light emitting device as claimed in claim 1 , wherein
the LED chip is placed within a recess portion of the substrate,
the primer covers a bottom face of the recess portion of the substrate,
the sealing resin portion is in close contact with the surface of the primer and seals the LED chip, and
the primer is not exposed.
18 . The light emitting device as claimed in claim 1 , wherein
the sealing resin portion is made from silicone resin.
19 . The light emitting device as claimed in claim 1 , wherein
the sealing resin portion contains a fluorophor.
20 . The light emitting device as claimed in claim 1 , wherein
a refractive index of the sealing resin portion and a refractive index of the primer, both being within a range of 1.2 to 1.8, are generally equal to each other.
21 . The light emitting device as claimed in claim 1 , further comprising
a reflector which is placed around the LED chip and which reflects light emitted by the LED chip.
22 . The light emitting device as claimed in claim 21 , wherein
the reflector and the substrate are made from one identical base material.
23 . The light emitting device as claimed in claim 21 , wherein
a surface of the reflector is made from Ag, or AgBi-based alloy, or AgNd-based alloy, or an Ag alloy containing 0.5 to 5.0 wt % of at least one kind of metal selected from Pt, Au, Cu, Pd, Mg, Ti and Ta.
24 . The light emitting device as claimed in claim 21 , wherein
the primer covers the surface of the reflector.
25 . The light emitting device as claimed in claim 1 , wherein
a coefficient of thermal expansion of the sealing resin portion and a coefficient of thermal expansion of the primer are generally equal to each other.
26 . A method for producing the light emitting device as claimed in claim 24 , comprising the step of:
applying the primer onto the surface of the reflector before placing the reflector around the LED chip.
27 . A method for producing the light emitting device, comprising the steps of:
applying a resin-made primer onto a substrate in which a metal portion is formed on its surface and on which an LED chip is mounted so that the resin-made primer covers at least part of the metal portion; and
coating the LED chip and at least part of the resin-made primer with a sealing resin and curing the sealing resin, thereby forming a sealing resin portion, wherein
the primer is made from a resin higher in gas barrier property than the sealing resin portion.
28 . A method for mounting the light emitting device as claimed in claim 1 onto a printed board onto which a primer made from a resin material identical to that of the primer has been applied.