1. Field of Invention
The present invention relates to a light source module. More particularly, the present invention relates to a light source module for increasing a light emission angle of a light-emitting diode.
2. Description of Related Art
Because the luminous efficiency of a traditional incandescent light bulb is bad, the incandescent light bulb is very likely to be prohibited in various countries of the world under environmental protection and energy saving trends. A light-emitting diode (LED) has great potential for substituting the incandescent light bulb. A light emission angle of the incandescent light bulb can reach to about 300 degrees (the light emission angle is estimated by using an angle range developed by the light with half of the maximum light intensity). A traditional LED has a Lambertion light field distribution, and thus a LED lamp constructed from a plurality of LEDs has a small light-outputting angle because of the Lambertion light field distribution, and when the lamp is used in a bigger space, it is very difficult to achieve a uniform (omnidirectional) illumination distribution for the LED lamp. Therefore, the LED lamp may not only cause a problem of direct glare but also cause the generation of light speckles, thus limiting the speed of substituting the incandescent light bulb with the LED lamp.