Light guide element and light source device using the light guide element
A light guide element and a light source device using the same are provided. The light guide element has a main body. The main body has a hollow portion with a cone shape and a microstructure pattern formed on the main body. The cone-shaped hollow portion has a bottom portion and a top portion. The bottom portion is located on the bottom surface of the main body, and has a first hollow cross section area. The top portion is opposite to the bottom surface, and has a second cross section area smaller than the first cross section area. The microstructure pattern includes high-density areas and low-density areas to improve a light distribution caused by the cone-shaped hollow portion. The light source device includes the light guide element and a ht emitting diode (LED). The LED is used to emit light into the cone-shape hollow portion through the bottom portion.
1. A light guide element, comprising:
a main body having:
an upper optic surface;
a lower optic surface opposite to the upper optic surface; and
a cross-sectional cone-shaped hollow portion located at the lower optic surface and used to receive exterior light;
wherein at least one of the upper optic surface and the lower optic surface has a first microstructure pattern comprising a plurality of high-density areas and a plurality of low-density areas, and the high-density areas and the low-density areas are arranged alternately, and the high-density areas have microstructures designed with a density higher than a density of microstructures in the low-density areas;
wherein the cross-sectional cone-shaped hollow portion comprises:
a bottom portion located at the lower optic surface, and having a first hollow cross-sectional area; and
a top portion opposite to the bottom portion, and having a second hollow cross-sectional area, wherein the second hollow cross-sectional area is smaller than the first hollow cross-sectional area, and a center of concentric circles formed by the low-density areas and the high-density areas is located on the top portion.
2. The light guide element of claim 1 , wherein the cone-shaped hollow portion is in a shape of a polygon cone.
3. The light guide element of claim 1 , wherein the microstructures in the low-density areas and the high-density area have the same size, but pitches between the microstructures in the high-density areas are smaller than pitches between the microstructures in the low-density areas.
4. The light guide element of claim 1 , wherein the microstructures in the low-density areas and the high-density areas have different sizes.
5. The light guide element of claim 1 , wherein the other one of the upper optic surface and the lower optic surface without having the first microstructure pattern has a second microstructure pattern comprising a plurality of high-density areas and a plurality of low-density areas, and the high-density areas of the second microstructure pattern are opposite to the low-density areas of the first microstructure pattern, and the low-density areas of the second microstructure pattern are opposite to the high-density areas of the first microstructure pattern.
6. The light guide element of claim 1 , wherein the other one of the upper optic surface and the lower optic surface without having the first microstructure pattern has a second microstructure pattern having a plurality of microstructure areas, and the microstructure areas have a uniform density distribution.
7. The light guide element of claim 1 , wherein the other one of the upper optic surface and the lower optic surface without having the first microstructure pattern has a second microstructure pattern having a plurality of microstructure areas, and a density of each of the microstructure areas of the second microstructure pattern is increased with increasing of a distance between the cone-shaped hollow portion and each of the microstructure areas of the second microstructure pattern.
8. The light guide element of claim 1 , wherein the first microstructure pattern is located on the lower optic surface.
9. The light guide element of claim 1 , wherein the first microstructure pattern is located on the upper optic surface.
10. A light source device comprising:
a light guide element comprising:
a main body having:
an upper optic surface;
a lower optic surface opposite to the upper optic surface; and
a cross-sectional cone-shaped hollow portion located at the lower optic surface and used to receive exterior light; and
a light, source disposed to emit light into the main body of the light guide element through the cone-shaped hollow portion;
wherein at least one of the upper optic surface and the lower optic surface having a first microstructure pattern comprising a plurality of high-density areas and a plurality of low-density areas; and
wherein a distance between the low-density area closest to the cross-sectional cone-shaped hollow portion and the cross-sectional cone-shaped hollow portion is predetermined to be shorter along with the decreasing of an absolute value of a predetermined slope rate of a surface of the cross-sectional cone-shaped hollow portion.
11. The light source device of claim 10 , wherein the microstructures in the low-density areas and the high-density areas have the same size, but pitches between the microstructures in the high-density areas are smaller than pitches between the microstructures in the low-density areas.
12. The light source device of claim 10 , wherein the microstructures in the low-density areas and the high-density areas have different sizes.
13. The light source device of claim 10 , wherein the other one of the upper optic surface and the lower optic surface without having the first microstructure pattern has a second microstructure pattern comprising a plurality of high-density areas and a plurality of low-density areas, and the high-density areas of the second microstructure pattern are opposite to the low-density areas of the first microstructure pattern, and the low-density areas of the second microstructure pattern are opposite to the high-density areas of the first microstructure pattern.
14. The light source device of claim 10 , wherein the other one of the upper optic surface and the lower optic surface without having the first microstructure pattern has a second microstructure pattern having a plurality of microstructure areas, and the microstructure areas have a uniform density distribution.
15. The light source device of claim 10 , wherein the other one of the upper optic surface and the lower optic surface without having the first microstructure pattern has a second microstructure pattern having a plurality of microstructure areas, and a density of each of the microstructure areas of the second microstructure pattern is increased with increasing of a distance between the cone-shaped hollow portion and each of the microstructure areas of the second microstructure pattern.