Light-emitting device including a Distributed Bragg Reflector (DBR) film
A light-emitting device includes a light-emitting element mounted on a base substrate, a reflective member that is formed on the base substrate and surrounds the light-emitting element, a transparent member that has a flat upper surface and is placed to cover above the light-emitting element, and a DBR film placed on the upper surface of the transparent member. A relation between an incident angle of light emitted from the light-emitting element and input into the DBR film and a transmittance of the light to pass through the DBR film is obtained such that a peak of the transmittance is in a range of the incident angle greater than 0°.
1. A light-emitting device, comprising:
a light-emitting element mounted on a base substrate;
a reflective member that is formed on the base substrate and surrounds the light emitting element;
a transparent member that has a flat upper surface and is placed to cover above the light-emitting element; and
a distributed Bragg reflector (DBR) film placed on the upper surface of the transparent member,
wherein the reflective member covers side surfaces of the light-emitting element,
wherein the transparent member comprises a first portion covering the upper surface of the light-emitting element and a second portion having a plate shape and placed on the upper surface of the first portion and the upper surface of the reflective member, and
wherein the reflective member covers side surfaces of the first portion.
2. The light-emitting device according to claim 1 , wherein a relation between a light distribution angle and an emission intensity is obtained such that the emission intensity at a light distribution angle of 0° is not more than 10% of a peak of the emission intensity.
3. The light-emitting device according to claim 1 , wherein all side surfaces of the transparent member are covered with the reflective member.
4. The light-emitting device according to claim 3 , wherein an inner side surface of the reflective member is inclined so that a space inside the reflective member is widened upward, and
wherein the transparent member fills the space inside the reflective member and covers the upper and side surfaces of the light-emitting element.
5. The light-emitting device according to claim 4 , wherein the inner side surface of the reflective member comprises an inverted truncated cone-shaped side surface.
6. The light-emitting device according to claim 5 , wherein the inner side surface of the reflective member comprises an inverted truncated pyramid-shaped side surface.
7. The light-emitting device according to claim 4 , wherein the inner side surface of the reflective member includes plural surfaces having different inclination angles.
8. The light-emitting device according to claim 4 , wherein the inner side surface of the reflective member includes a curved surface.
9. The light-emitting device according to claim 4 , wherein the inner side surface of the reflective member includes a first inclined surface and a second inclined surface that form respectively different inverted truncated pyramid shapes.
10. The light-emitting device according to claim 4 , wherein the inner side surface of the reflective member comprises a first inclined surface inclined at a first angle with respect to the upper surface of the base substrate and a second inclined surface inclined at a second angle with respect to the upper surface of the base substrate and located on the upper side of the first inclined surface, the second angle being smaller than the first angle.
11. The light-emitting device according to claim 10 , wherein the first angle of the first inclined surface is in a range of 25°-35°.
12. The light-emitting device according to claim 10 , wherein the second angle of the second inclined surface is in a range of 5°-15°.
13. The light-emitting device according to claim 11 , wherein the second angle of the second inclined surface is in a range of 5°-15°.
14. The light-emitting device according to claim 3 , wherein a relation between a light distribution angle and an emission intensity is obtained such that the emission intensity at a light distribution angle of 0° is not more than 5% of a peak of the emission intensity.
15. The light-emitting device according to claim 1 , wherein the transmittance of light to pass through the DBR at 0° is not more than 20% of a peak of the transmittance.
16. The light-emitting device according to claim 15 , wherein the transmittance of the light to pass through the DBR at 0° is not more than 10% of the peak transmittance.