BACKGROUND
1. Technical Field
The present disclosure relates generally to lighting systems and, more particularly, to an illumination apparatus utilizing light emitting diodes (LEDs) as light sources.
2. Description of Related Art
LED as a new type of light source can generate brighter light, and have many advantages, e.g., energy saving, environment friendly and longer life-span, compared to conventional light sources. Therefore, the LED has a trend of substituting for conventional light source.
Nowadays one disadvantage of an illumination apparatus applying LEDs is the low utilization efficiency of light sources, in which an amount of light from the lamp always projects/illuminates an area not needed to be illuminated. Thus, a great deal of electric energy is consumed unnecessarily.
What is needed, therefore, is an illumination apparatus utilizing LED light sources which can overcome the limitations described.
BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is an isometric, assembled view of an LED module in accordance with an embodiment of the disclosure.
FIG. 2 is an isometric, inverted view of the LED module of FIG. 1, wherein an LED is removed therefrom.
FIG. 3 is a cross-sectional view of the LED module of FIG. 1, taken along line III-III thereof.
FIG. 4 is a cross-sectional view of the LED module of FIG. 1, taken along line IV-IV thereof.
FIG. 5 shows an equal illumination intensity distribution of the LED module simulated by a computer software.
FIG. 6 is a diagram illustrating a luminous intensity distribution of the LED module of FIG. 1.
FIG. 7 shows a plurality of LED modules of FIG. 1 integrated together as an LED lamp.
FIG. 8 shows a street lamp using the LED lamp of FIG. 7.
DETAILED DESCRIPTION
Referring to FIG. 1 and FIG. 3, an LED module 30 in accordance with an embodiment of the disclosure includes an LED 10 and a lens 20 covering the LED 10. The LED 10 includes a base 12, an LED chip 14 mounted on a top face of the base 12, a transparent encapsulant 16 sealing the LED chip 14 and fixed on the top face of the base 12 and a board 18 disposed on a bottom face of the base 12. The encapsulant 16 is substantially hemispherical. Light emitted from the LED chip 14 passes through the encapsulant 16 when the LED chip 14 is energized. The LED 10 has an optical axis A.
Also referring to FIG. 2 and FIG. 4, the lens 20 is integrally made from a transparent material with good optical property, such as PMMA or PC. The lens 20 includes a light directing portion 23 and a flange 25 extending outwardly from a bottom of the light directing portion 23. The light directing portion 23 has a light input face and a light output face 21. The light input face is for an incidence of the light from the LED 10 into the light directing portion 23 of the lens 20. The light output face 21 can refract the light from the light input face and includes a first light output face 22 continuously distributed from a center to a periphery thereof and four second light output faces 24 inwardly recessed relative to the first light output face 22. The light output face 21 has an optical axis B which is coincident with the optical axis A of the LED 10 (shown in FIG. 3). The four second light output faces 24 space from each other with the same interval and are away from the optical axis B of the light output face 21, and are symmetrical about the optical axis B, thereby making the first light output face 22 substantially be a crisscross in shape. The first light output face 22 is an outwardly convex spheric face. Each second light output face 24 is an inwardly concave ellipsoid face. The ellipsoid face can deflect light extending therethrough toward the first light output face 22 adjacent thereto (referring to arrow b shown in FIG. 4), thus making an area on which the entire LED module 30 illuminates be in a crisscross shape. It is noted that the second light output face 24 can be other inwardly depressed curved face, such as a curved face consisting of two intersecting planes, as long as light extending through the second light output face 24 can be deflected toward the first light output face 22 adjacent thereto.
Particularly referring to FIG. 2 and FIG. 3, the lens 20 inwardly defines a step-shaped position groove 26 in a center of a bottom thereof for receiving the base 12 and the board 18 of the LED 10 therein. A hemispherical cavity 28 is further inwardly defined in a center of the position groove 26 for receiving the encapsulant 16 of the LED 10 therein. A face of the cavity 28 is a spheric face and acts as the light input face for the light produced by the LED 10 entering into the light directing portion 23 of the lens 20. The face of the cavity 28 has an optical axis C which is coincident with the optical axis A and the optical axis B. The face of the cavity 28 for functioning as the light input face can be an aspheric face in an alternative embodiment.
FIG. 5 shows an equal illumination intensity distribution of the LED module 30 simulated by a computer software. An obvious crisscross pattern shown in FIG. 5 indicates that the light from the LED module 30 is mostly focused on the crisscross area.
FIG. 6 shows a luminous intensity distribution of the light from the LED module, wherein values of an abscissa represent angles of the light offset from the optical axis A, and each value of an ordinate represents a value of luminous intensity.
In the light from the LED module 30, the light generally coincident with the optical axis A has a maximum luminous intensity. The larger the angle of the light offset from the optical axis A is, the smaller luminous intensity of the light is. The light has half of the maximum luminous intensity as the angle of the light offset from the optical axis A is 67.5 degrees. Luminous intensity of the light reduces from half of the maximum luminous intensity to 0 as the angle of the light offset from the optical axis A ranges from 67.5 degrees to 82 degrees; thus, a maximum illumination range of the light from the LED module 30 is 164 degrees.
It is noted that a plurality of such LED modules 30 can be integrated on a frame 40 (shown in FIG. 7) to form an LED lamp, which can intensify luminous intensity of the light from the LED lamp and illuminate a place needing a large degree of illumination.
Also referring to FIG. 8, when a street lamp 50 which uses the LED lamp of FIG. 7 consisting of the LED modules 30 is mounted at a crossing/junction at which roads 60 intersect/meet, the first light output faces 22 of the lenses 20 can converge the light extending therethrough toward the crossing (referring to arrows a shown in FIG. 4). The second light output faces 24 of the lenses 20 can direct the light extending therethrough toward the crossing (referring to arrows b shown in FIG. 4) and minimize the light toward neighboring regions of roads 60. Thus, the light from the LED modules 30 is focused over the crossing to form an intersecting illumination area 70, and an unnecessary illumination out of the roads 60 is avoided.
In the disclosure, the second light output faces 24 in conjunction/combination with the first light output face 22 of the lens 20 of the LED module 30 can refract the light from the LED 10 toward the predefined area where illumination is needed, whereby utilization efficiency of the LED light source is thus enhanced.
It is believed that the disclosure and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
Patent Application
20110019400
