Patent Application
20130170203
The present application is based on, and claims priority from, Taiwan Application Serial Number 100149273, filed on Dec. 28, 2011, the disclosure of which is hereby incorporated by reference herein in its entirety.
1. Technical Field
The disclosure relates to an optical engine, and particularly relates to a light-emitting diode (LED) array light source in the optical engine.
2. Description of Related Art
In recent years, light-emitting efficiency of LED continues to advance, and the LED has replaced fluorescent lamps and incandescent lamps in some fields. Such fields include scanning lamps with high response speed, back light sources or front light sources of light crystal displays (LCDs), light sources for car dashboards, traffic lights, light sources of projection unites, conventional illumination apparatuses, and so on. Specifically, the LED has a service life of more than 100,000 hours and does not require idling time. In addition, the LED has advantages of high response speed (about 10−9 seconds), small volume, low power consumption, low degree of pollution, high reliability, good adaptation to mass production, and so on. Thus, the LED is extensively applied in various fields.
The LED is a Lambertian-like light source and frequently has the full width at half maximum (FWHM) of light-intensity peak from about 55° to about 60°. In the existing technology, an effective utilization rate of the LED in a projection unit with a light-receiving half angle of 15° merely ranges from about 6% to about 10%. Apparently, collimation and light-emitting efficiency of the existing LED are not satisfactory enough. Hence, how to ameliorate the collimation and the light-emitting efficiency of the LED without significantly increasing the volume and the weight of the light source has become a focus to researchers and designers in this field.
In the disclosure, an LED array light source including a substrate, a meshed light-shielding layer, a plurality of LED chips, and a micro-lens array is provided. The meshed light-shielding layer is disposed on the substrate and includes a plurality of bar-shaped light-shielding patterns intersected with one another to define a plurality of openings arranged in array. Each of the bar-shaped light-shielding patterns has a bottom surface in contact with the substrate, a top surface, and two side surfaces, a width of the top surface is smaller than a width of the bottom surface, and a thickness of the meshed light-shielding layer is T1. Each of the LED chips is exclusively located in one of the openings and disposed on the substrate. The micro-lens array covers the substrate, the meshed light-shielding layer, and the LED chips and includes a plurality of micro-lenses arranged in array. Each of the micro-lenses respectively includes a base portion in contact with the meshed light-shielding layer and a lens portion connected to the base portion, and each of the micro-lenses is disposed corresponding to one of the openings, respectively. A vertical distance from a top portion of each of the micro-lenses to the bottom surface is T2, and 0.278≦T1/T2≦0.833.
In the disclosure, an optical engine including the aforesaid LED array light source and a projection unit is further provided. The LED array light source serves to provide a light beam, and the projection unit is disposed on a transmission path of the light beam. Besides, a light-receiving half angle of the projection unit is approximately 15°.
Several exemplary embodiments accompanied with figures are described in detail below to further describe the disclosure in details.
The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments and, together with the description, serve to explain the principles of the disclosure.
The disclosure is directed to an LED array light source with favorable light-emitting efficiency.
The disclosure is further directed to an optical engine with favorable display quality.
For instance, the thickness T1 and the distance T2 satisfy the following equation:
0.278≦T1/T2≦0.833.
When the thickness T1 and the distance T2 satisfy 0.278≦T1/T2≦0.833, the collimation and the light-emitting efficiency of the LED array light source 110 may be improved.
In the present embodiment, the bottom surface 114a2 is substantially parallel to the top surface 114a1, and an included angle α between each of the side surfaces 114a3 and the bottom surface 114a2 is substantially the same. That is to say, if the bottom surface 114a2 serves as the basis, the two side surfaces 114a3 have substantially the same degree of tilt. Besides, the width W2 of the bottom surface 114a2 substantially ranges from 20 μm to 35 μm, for instance, and the width W1 of the top surface 114a1 substantially ranges from 1 μm to 5 μm, for instance. Note that the included angle α is relevant to the width W1 and the width W2, and the appropriate included angle α may be calculated based on actual design requirement in the disclosure.
According to the present embodiment, the meshed light-shielding layer 114 may be formed in various manner. For instance, the meshed light-shielding layer 114 may be formed through electroforming, stacking and bonding metal films, stencil printing, and so on, so as to obtain the meshed light-shielding layer 114 with the expected thickness.
Here, the pitch P between the lens portions 118a2 substantially ranges from 10 μm to 60 μm, for instance, and a curvature radius of each of the lens portions 118a2 substantially ranges from 5 μm to 60 μm, for instance. In addition, the base portions 118a1 of the micro-lens 118a and the lens portions 118a2 are integrally formed, for instance. Namely, the base portions 118a1 and the lens portions 118a2 are made of the same material. For instance, the micro-lens array 118 may be formed by highly precise mold through injection molding.
It can be learned from Table 1 that the design concept of the disclosure can significantly help ameliorate the light-emitting efficiency of the LED array light source and is therefore quite applicable to the field of micro-projection.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 100149273 | Dec 2011 | TW | national |
