Light emitting diode lamp

A light emitting diode (LED) lamp includes a substrate, a plurality of LED elements arranged on the substrate, and a reflector arranged on the substrate. The reflector includes a plurality of reflecting sheets obliquely extending upward and outward from a center of the substrate. A projection of each of the reflecting sheets covers one LED element. Each of the reflecting sheets corresponding to the LED element defines a perforation. Part of light from the LED element directly radiates out via the perforation, and part of light from the LED package is reflected to a lateral periphery of the substrate by the reflecting sheet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a related application of U.S. patent application Ser. No. 14/449,591 filed on Aug. 01, 2014, entitled “LIGHT EMITTING DIODE LAMP”, assigned to the same assignee.

FIELD

The disclosure relates to semiconductor emitting device, and more particularly to a light emitting diode (LED) lamp.

BACKGROUND

LEDs have low power consumption, high efficiency, quick reaction time, long lifetime, and the absence of toxic elements such as mercury during manufacturing. Due to those advantages, traditional light sources are gradually replaced by LEDs.

A conventional LED lamp includes a substrate and a plurality of LEDs arranged on the substrate. The LEDs are usually densely arranged in array on the top surface of the substrate. However, the conventional LED generally generates a smooth round light field with a radiation angle of 90 degrees (−45 degrees to 45 degrees), wherein the light at a center of the conventional LED (i.e., 0 degree) is relatively great and the light at a periphery of the conventional LED is relatively poor. Such that, light emitted by the LED lamp including the conventional LEDs densely arranged on the substrate has a small radiation angle and is unevenly distributed, and thereby a whole light output of the LED lamp is barely satisfactory for illumination.

DETAILED DESCRIPTION

Referring toFIGS. 1 and 2, an LED lamp100in accordance with a first embodiment is provided. The LED lamp100includes a substrate10, a plurality of LED elements20arranged on the substrate10and a reflector30arranged on the substrate10.

Specifically, the substrate10is annular but not limited to be annular. The substrate10includes a top surface11and a bottom surface12opposite to the top surface11. A through hole13is defined at a center of the substrate10, the through hole13penetrates the top surface11and the bottom surface12for fixing the LED lamp100by engaging with other components (not shown). The top surface11of the substrate10is provided with circuit lines (not shown) electrically connecting with the LED elements20. In this embodiment, the substrate10is a printed circuit board. Alternatively, the substrate10could also be ceramic substrate or Aluminum substrate for better cooling effects.

The LED elements20are arranged on the top surface11of the substrate10and located at a lateral periphery of the through hole13. In this embodiment, the LED elements20are annularly arranged in a circle. Alternatively, an arranging shape of the LED elements20could be adjusted according to actual light radiating requirements, such as triangle, square and so on. Each of the LED elements20is an LED package, and the LED package could be coupled with phosphor to change a color of the light radiating from the LED package.

The reflector30includes a cylindrical connector31and a plurality of flat reflecting sheets32obliquely extending upward from the connector31. In this embodiment, the reflector30is made of plastic materials by injecting molding. Alternatively, the reflector30could also be constructed of metal by means of compression molding.

In at least one embodiment, the connector31is a cylindrical sheet. The connector31vertically extends upward from the top surface11of the substrate10. Alternatively, the connector31could also obliquely extend upward from the substrate10. The connector31surrounds the through hole13. The LED elements20surround the connector31. Preferably, the LED elements20resist an outer surface of the connector30for increasing a reflection of the light radiating from the LED elements20.

The reflecting sheets32obliquely extend upward and outward from a top end of the connector31. The reflecting sheets32and the connector31are integrally formed as a single piece. A free end of each of the reflecting sheets32is located right above the lateral periphery of the substrate10. The reflecting sheets32are symmetrically arranged relative to an axis O-O1of the connector31. The axis O-O1is superposed with that of the through hole13of the substrate10.

Each of the reflecting sheets32is a longitudinal flat sheet with a constant width. A space L is defined between two adjacent reflecting sheets32, and a dimension of the space L is gradually increased along an extending direction of the reflecting sheets32from the connector31. A number of the reflecting sheets32is equal to that of the LED elements20in this embodiment. Each of the reflecting sheets32correspondingly covers one LED element20, that is a projection of each of the reflecting sheets32on the substrate10correspondingly covers one LED element20. The reflecting sheets32have a larger area than the LED elements20, and the projection of each reflecting sheet32completely covers the corresponding LED element20and extends beyond a periphery of the corresponding LED element20.

Each of the reflecting sheets32includes a reflecting surface321facing to the corresponding LED element20. The reflecting surface321is flat and reflects part of light emitted by the LED element20to the lateral periphery of the substrate10, and thereby a radiation angle of the LED lamp100is increased. An angle θ is defined between the reflecting surface321and a horizontal surface where the top end of the connector31(and of course the substrate10) is located at. The angle θ ranges from 25 degrees to 45 degrees, that is the angle between the reflecting surface321and the horizontal surface parallel to the substrate10ranges from 25 degrees to 45 degrees.

One end of each of the reflecting sheets32adjacent to the connector31defines a perforation322corresponds the LED element20covered by the reflecting sheet32, that is each of the perforations322is located right above the LED element20. In this embodiment, a dimension of the perforation322is equal to that of the corresponding LED element20. Alternatively, the dimension of the perforation322could also be smaller than that of the LED element20covered by the reflecting sheet32.

During the operation of the LED lamp100, part of light emitted by the LED element20near to a center of the radiation angle directly radiates upward and out via the perforation322. Simultaneously, part of light bias from the center of the radiation angle directly radiates upward and out via the space L between each two adjacent reflecting sheets32, and part of light are reflected to the lateral periphery of the substrate10by the outer surface of the connector31and the reflecting surface321of the reflecting sheet32.

FIGS. 3 and 4illustrate a comparison between a traditional LED lamp and the LED lamp provided by the present disclosure.FIG. 3shows a light distribution curve of the traditional LED lamp (without reflector),FIG. 4shows a light distribution curve of the LED lamp100, wherein the angle θ is 45 degrees. InFIG. 3andFIG. 4, the horizontal axis represents the light radiation angle (in degree), and the vertical axis represents normalized intensity. Compared to the light distribution of the traditional lamp, a half-power angle (a light radiation angle corresponding to a half light intensity of the highest light intensity) is changed to 156 degrees from 120 degrees, such that the light radiation angle of the LED lamp100is increased, and thereby a light radiation filed of the LED lamp100is correspondingly increased. In addition, a light brightness of the LED lamp100at a center thereof is substantially equal to a light brightness of the LED lamp100at a periphery thereof, such that the light radiating from the LED lamp100is evenly distributed.

Since the LED lamp100of present disclosure includes a reflector30corresponding to the plurality of LED elements20, the reflecting sheets32of the reflector30each covers one LED element20and reflects part of light emitted by the LED element20to the lateral periphery of the substrate10. Therefore, the light radiation angle of the LED lamp100is increased. In addition, since part of light emitted by the LED element20directly radiates out via the perforation322, which leads to the light brightness of the LED lamp100at a center thereof is substantially equal to a light brightness of the LED lamp100at a periphery thereof, such that the light radiating from the LED lamp100is evenly distributed.

Alternatively, the angle θ is not limited to 45 degrees. Referring to sheet1as below, the specific data shows relationships between the angle θ and the half-power angle of the LED lamp100. When the angle θ gradually decreases, the half-power angle of the LED lamp100gradually increases. The angle θ ranges from 25 degrees to 45 degrees for keeping balance between the light radiation angle and the light intensity of the LED lamp100.

Alternatively, the quantity of the reflecting sheets32may not be equal to that of the LED elements20. In at least one embodiment, a plurality of annularly arranged groups of LED elements20could also be arranged on the substrate10, that is one reflecting sheet32correspondingly cover several LED elements20. Alternatively, the reflector30could also not comprise the connector31, that is the reflecting sheets32are directly arranged on the substrate10and extend upward and outward.

Referring toFIG. 5, an LED lamp200in accordance with a second embodiment is provided. The LED lamp200is similar to the LED lamp100, the difference is that the connector31and part of the top surface11of the substrate10surrounded by the connector31are engaged together to form a receiving portion311, and a plurality of assistant LED elements20′ are arranged on the top surface11of the substrate10surrounded by the connector31. In other words, the assistant LED elements20′ are received in the receiving portion311. The LED elements20and the assistant LED elements20are separated from each other by the connector31, and the assistant LED elements20′ surround the through hole13. Preferably, the assistant LED elements20′ received in the receiving portion311resist an inner surface of the connector31.

It is to be understood that the above-described embodiments are intended to illustrate rather than limit the disclosure. Variations may be made to the embodiments without departing from the spirit of the disclosure. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure and do not limit the scope of the following claims.