Semiconductor light-emitting device
View Patent ↗A semiconductor light emitting device includes: a semiconductor chip having a growth surface that is a nonpolar or semipolar plane, and emitting polarized light; and a reflector having a reflective surface. At least part of light in a plane L 90 is reflected off the reflective surface in a direction of a normal line to the growth surface, and an amount of light reflected off the reflective surface in the plane L 90 in the direction of the normal line is larger than that of light reflected off the reflective surface on a plane L 45 in the direction of the normal line, where the plane L 90 represents a plane including the normal line and oriented at 90° to a polarization direction of the polarized light, and the plane L 45 represents a plane including the normal line, and oriented at 45° to the polarization direction of the polarized light.
1. A semiconductor light emitting device comprising:
a semiconductor light emitting chip having a growth surface that is a nonpolar or semipolar plane, and emitting polarized light; and
a reflection member having a plurality of reflective surfaces off which the polarized light is reflected, wherein
at least part of light in a plane L 90 is reflected off the reflective surfaces in a direction of a normal line to the growth surface, and an amount of light reflected off the reflective surfaces in the plane L 90 in the direction of the normal line to the growth surface is larger than an amount of light reflected off the reflective surfaces in a plane L 45 in the direction of the normal line to the growth surface, where the plane L 90 represents a plane including the normal line to the growth surface of the semiconductor light emitting chip and oriented at an angle of 90° to a polarization direction of the polarized light, and the plane L 45 represents a plane including the normal line, and oriented at an angle of 45° to the polarization direction of the polarized light,
the reflective surfaces are arranged such that a shape formed by the reflective surfaces when viewed in plan is square, and
an angle θ2 is either not less than 0° and not more than 10° or not less than 80° and not more than 90°, where θ2 represents an angle between a polarization direction of the polarized light and a side of the shape formed by the reflective surfaces when viewed in plan.
2. The semiconductor light emitting device of claim 1 , wherein
an arithmetic average inclination angle Δθ1z is larger than an arithmetic average inclination angle Δθ1y, where the arithmetic average inclination angle Δθ1y represents an angle between each of the reflective surfaces and the direction of the normal line to the growth surface of the semiconductor light emitting chip when viewed in cross section take along the plane L 90 , and the arithmetic average inclination angle Δθ1z represents an angle between each of the reflective surfaces and the direction of the normal line to the growth surface of the semiconductor light emitting chip when viewed in cross section take along the plane L 45 .
3. The semiconductor light emitting device of claim 2 , wherein
the arithmetic average inclination angle θ1y is not less than 20° and not more than 40°.
4. The semiconductor light emitting device of claim 2 , wherein
the arithmetic average inclination angle θy1 is not less than 25° and not more than 40°.
5. The semiconductor light emitting device of claim 1 , wherein
corner portions of the shape formed by the reflective surfaces when viewed in plan have a curved surface, and
a curvature R of the curved surface is less than a length of a shortest side of the semiconductor light emitting chip.
6. The semiconductor light emitting device of claim 1 , wherein
the semiconductor light emitting chip includes at least two semiconductor light emitting chips, and
the at least two semiconductor light emitting chips are arranged such that directions of polarization of light from the at least two semiconductor light emitting chips are identical.
7. The semiconductor light emitting device of claim 1 , wherein
the semiconductor light emitting chip includes at least four semiconductor light emitting chips,
the at least four semiconductor light emitting chips are arranged in a matrix such that directions of polarization of light from the at least four semiconductor light emitting chips are identical, and
D2 is less than D1, where D1 represents a distance between adjacent two of the at least four semiconductor light emitting chips arranged in a direction perpendicular to the directions of polarization of the light, and D2 represents a distance between adjacent two of the at least four semiconductor light emitting chips arranged in a direction parallel to the directions of polarization of the light.
8. The semiconductor light emitting device of claim 1 further comprising:
a wavelength conversion member covering the semiconductor light emitting chip.
9. The semiconductor light emitting device of claim 1 , wherein
a linear reflectivity of each of the reflective surfaces is higher than a diffuse reflectivity of the reflective surface.
10. The semiconductor light emitting device of claim 1 , wherein
a surface roughness of each of the reflective surfaces is not more than 100 nm.
11. A semiconductor light emitting device comprising:
a semiconductor light emitting chip having a growth surface that is a nonpolar or semipolar plane, and emitting polarized light; and
a reflection member having a plurality of reflective surfaces off which the polarized light is reflected, wherein
at least part of light in a plane L 90 is reflected off the reflective surfaces in a direction of a normal line to the growth surface, and an amount of light reflected off the reflective surfaces in the plane L 90 in the direction of the normal line to the growth surface is larger than an amount of light reflected off the reflective surfaces in a plane L 45 in the direction of the normal line to the growth surface, where the plane L 90 represents a plane including the normal line to the growth surface of the semiconductor light emitting chip and oriented at an angle of 90° to a polarization direction of the polarized light, and the plane L 45 represents a plane including the normal line, and oriented at an angle of 45° to the polarization direction of the polarized light,
the reflective surfaces are arranged such that a shape formed by the reflective surfaces when viewed in plan is rectangular, and
an angle θ2 is either not less than 0° and not more than 10° or not less than 85° and not more than 90°, where θ2 represents an angle between a polarization direction of the polarized light and a long side of the shape formed by the reflective surfaces when viewed in plan.
12. The semiconductor light emitting device of claim 11 , wherein
an arithmetic average inclination angle Δθ1z is larger than an arithmetic average inclination angle Δθ1y, where the arithmetic average inclination angle Δθ1y represents an angle between each of the reflective surfaces and the direction of the normal line to the growth surface of the semiconductor light emitting chip when viewed in cross section take along the plane L 90 , and the arithmetic average inclination angle Δθ1z represents an angle between each of the reflective surfaces and the direction of the normal line to the growth surface of the semiconductor light emitting chip when viewed in cross section take along the plane L 45 .
13. The semiconductor light emitting device of claim 12 , wherein
the arithmetic average inclination angle θ1y is not less than 20° and not more than 40°.
14. The semiconductor light emitting device of claim 12 , wherein
the arithmetic average inclination angle θy1 is not less than 25° and not more than 40°.
15. The semiconductor light emitting device of claim 11 , wherein
corner portions of the shape formed by the reflective surfaces when viewed in plan have a curved surface, and
a curvature R of the curved surface is less than a length of a shortest side of the semiconductor light emitting chip.
16. The semiconductor light emitting device of claim 11 , wherein
the semiconductor light emitting chip includes at least two semiconductor light emitting chips, and
the at least two semiconductor light emitting chips are arranged such that directions of polarization of light from the at least two semiconductor light emitting chips are identical.
17. The semiconductor light emitting device of claim 11 , wherein
the semiconductor light emitting chip includes at least four semiconductor light emitting chips,
the at least four semiconductor light emitting chips are arranged in a matrix such that directions of polarization of light from the at least four semiconductor light emitting chips are identical, and
D2 is less than D1, where D1 represents a distance between adjacent two of the at least four semiconductor light emitting chips arranged in a direction perpendicular to the directions of polarization of the light, and D2 represents a distance between adjacent two of the at least four semiconductor light emitting chips arranged in a direction parallel to the directions of polarization of the light.
18. The semiconductor light emitting device of claim 11 further comprising:
a wavelength conversion member covering the semiconductor light emitting chip.
19. The semiconductor light emitting device of claim 11 , wherein
a linear reflectivity of each of the reflective surfaces is higher than a diffuse reflectivity of the reflective surface.
20. The semiconductor light emitting device of claim 11 , wherein
a surface roughness of each of the reflective surfaces is not more than 100 nm.