LIGHT-EMITTING DEVICE USING MOUNTING SUBSTRATE
A light-emitting device uses a mounting substrate wherein insulation resistance of a metal substrate having an oxide film formed on the surface thereof is ensured, and light reflectance is improved by preventing a light-reflecting material contained in a reflection layer from diffusing into a surface of the metal substrate. The device includes a metal substrate formed of aluminum material, a surface layer section formed on an upper surface of the metal substrate, blue light-emitting diode elements mounted on the surface layer section through a transparent adhesive, and a light-transmitting resin body containing phosphor that seals the blue light-emitting diode elements. The surface layer section includes an oxide film layer containing an alumite layer and being formed on the upper surface of the metal substrate, a barrier layer formed on the oxide film layer, and a reflection layer formed on the barrier layer and containing silver.
1 . A lighting device comprising:
a metal substrate formed of aluminum material;
a surface layer section formed on an upper surface of the metal substrate;
a plurality of blue light-emitting diode elements mounted on the surface layer section through a transparent adhesive; and
a light-transmitting resin body containing phosphor that seals the plurality of blue light-emitting diode elements,
wherein the surface layer section includes:
an oxide film layer comprising an alumite layer, the oxide film layer being formed on the upper surface of the metal substrate;
a barrier layer formed on the oxide film layer;
a reflection layer containing silver, the reflection layer being formed on the barrier layer, and
wherein the barrier layer contains at least one of titanium, nickel, ruthenium, palladium, tungsten, and platinum.
2 . The lighting device according to claim 1 further comprising a reflection frame configured to surround the plurality of blue light-emitting diode elements, the reflection frame being disposed around the surface layer section.
3 . The lighting device according to claim 1 , further comprising:
at least two external connecting electrodes, one of the external connecting electrodes being located on a first side of the blue light-emitting diode elements and another of the external connecting electrodes being located on a second side of the blue light-emitting diode elements that is opposite to the first side; and
a plurality of bonding wires, each adjacent pair of the blue light-emitting diode elements being electrically connected together by one of the bonding wires, one of the blue light-emitting diode elements being electrically connected to the one of the external connecting electrodes by one of the bonding wires, and another of the blue light-emitting diode elements being electrically connected to the other of the external connecting electrodes by one of the bonding wires,
wherein the plurality of blue light-emitting diode elements is arranged on the surface layer section.
4 . The lighting device according to claim 1 , wherein a concentration of phosphor contained in the light-transmitting resin body is higher at a bottom of the light-transmitting resin body than at the top surface of the light-transmitting resin body.
5 . The lighting device according to claim 1 , wherein the barrier has a uniform thickness.
6 . The lighting device according to claim 1 , wherein the reflection layer is formed of a resin film made of a light-transmitting resin containing silver.
7 . The lighting device according to claim 1 , wherein the reflection layer is formed of a silver evaporated film.
8 . The lighting device according to claim 1 comprising a protection film layer formed of a light-transmitting resin film, the protection film layer being formed on the reflection film layer.
9 . The lighting device according to claim 1 comprising the protection film layer formed of a titanium oxide evaporated film or a silicon oxide evaporated film, the protection film layer being formed on the reflection film layer.
10 . The lighting device according to claim 1 , wherein
the protection film layer is formed of a multilayer film including the light-transmitting resin film, the titanium oxide evaporated film, and the silicon oxide evaporated film.