ILLUMINATION APPARATUS USING LASER DIODE AS LIGHT SOURCE

An illumination apparatus includes a laser diode and an encapsulation layer located at one side of the laser diode. A plurality of fluorescent powders is mixed in the encapsulation layer. A reflecting layer is provided. Light generated by a mixture of light generated by the laser diode and light generated by the fluorescent powders by excitation of the light generated by the laser diode has a part radiating out of the encapsulation layer after it is reflected by the reflecting layer.

DETAILED DESCRIPTION

Referring toFIG. 1, an illumination apparatus1in accordance with a first embodiment of the present disclosure includes a laser diode (LD)10, an encapsulation layer20located at a side of the laser diode10and in alignment with the laser diode10along a horizontal direction and a reflecting layer30coated on the encapsulation layer20. The encapsulation layer20is a rectangular parallelepiped.

A luminescence spectrum of the laser diode10is narrow, and the light emitted from the laser diode10is concentrated, whereby it is difficult to be intervened when it transmits through the air or other medium. The laser diode10mostly converts electric energy into optical energy, and hardly converts into heat energy, so the photoelectric conversion efficiency of the laser diode10is high. In this embodiment, light emitted from the laser diode10is blue light.

The encapsulation layer20is located at one side of the laser diode10, and is further mixed with fluorescent powder21therein. In this embodiment, the fluorescent powder21is yellow fluorescent powder. The encapsulation layer20includes a top surface22, a bottom surface23opposite to the top surface22, a left lateral surface24and a right lateral surface25opposite to the left lateral surface24. The laser diode10is adjacent to the left lateral surface24of the encapsulation layer20and distant from the right lateral surface25. A space is defined between the laser diode10and the left lateral surface24.

The reflecting layer30is attached on the top surface22and the right lateral surface25of the encapsulation layer20, and the cross-section of the reflecting layer30is L-shaped. Alternatively, the reflecting layer30can also cover a front side surface and a rear side surface of the encapsulation layer20, whereby more light can be directed downwardly.

In use of the illumination apparatus1, when the blue light emitted from the laser diode10is entered to an interior of the encapsulation layer40from the left lateral surface24, the fluorescent powder21in the encapsulation layer20is excited by a part of the blue light and generates yellow light. Then, the other part of the blue light is mixed with the yellow light to form the white light. A part of the white light is output directly from the bottom surface23and the front and rear side surfaces of the encapsulation layer20. The other part of the white light is transmitted to the top surface22and the right lateral surface25of the encapsulation layer20, reflected by the reflecting layer30and finally output from the bottom surface23and the front and rear sides surfaces of the encapsulation layer20, whereby the illumination apparatus1generates a linear illumination field. The illumination apparatus1can replace a conventional fluorescent tube.

Referring toFIG. 2, an illumination apparatus la in accordance with a second embodiment of the present disclosure is similar to the illumination apparatus1. The difference between the illumination apparatus1aand the illumination apparatus1is that, the laser diode10is located at the lower left of the encapsulation layer20, and the reflecting layer30acorrespondingly covers the top surface22of the encapsulation layer20, and the cross-section of the reflecting layer30ais arcuate. The reflecting layer30ais configured like a dome. Furthermore, the encapsulation layer20is configured like a disc. When the blue light emitted from the laser diode10is entered to the interior of the encapsulation layer40from the left lateral surface24, the fluorescent powder21in the encapsulation layer20is excited by a part of the blue light and generates yellow light. Then, the other part of the blue light is mixed with the yellow light to form the white light. Thus, part of the white light is output from the bottom surface23of the encapsulation layer20. The other part of the white light is transmitted to the reflecting layer30a, reflected by the reflecting layer30ato move downwardly and finally output from the bottom surface23of the encapsulation layer20, whereby the illumination apparatus1agenerates a circular illumination filed. The illumination apparatus1aof the second embodiment can replace a conventional light bulb.