This application claims priority to Taiwan Application Serial Number 101130669, filed Aug. 23, 2012, which is herein incorporated by reference.
1. Technical Field
Embodiments of the present invention relate to an illumination apparatus. More particularly, embodiments of the present invention relate to an illumination apparatus, an illumination module and an optical diffuser thereof.
2. Description of Related Art
In recent years, eco-friendly products have been the main stream in the market. Concerning the products for illumination, in order to save energy, the light emitting diode (LED), which has many advantages such as low power consumption and high efficiency, is widely applied in the illumination device. In the illumination device, the LED can be used to replace the incandescent light bulb and the fluorescent lamp. A LED lamp tube generally includes a light bar and a lampshade. The LEDs are mounted on the light bar, and the lampshade covers the light bar for protecting the LEDs.
However, the light emission angle of the LED is about 120 degrees, in which the illuminance beyond the light emission angle is seriously lower than that within the light emission angle, causing non-uniform illuminance. Under such circumstance, in case of the LED lamp tube installed on the ceiling, there is only a small part of the light illuminating the ceiling, such that the ceiling with lower illuminance is apt to make human eye uncomfortable.
A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.
One aspect of the present invention provides an optical diffuser, and this optical diffuser can be used to increase the emitting area or range of the light source, so as to make the illuminance of different areas more uniform. In accordance with one embodiment of the present invention, the optical diffuser includes a light incident curved surface and a light outgoing curved surface. The center of curvature of the light incident curved surface is positioned on the center of a light emitting surface of a light source. The center of the curvature of the light outgoing curved surface is positioned beneath the center of curvature of the light incident curved surface and deviates from the light source. The radius of curvature R1 of the light outgoing curved surface is greater than the radius of curvature R2 of the light incident curved surface.
Another aspect of the present invention provides an illumination module. In accordance with one embodiment of the present invention, the illumination module employs the LED as the light source, and further employs the foregoing optical diffuser to increase the emitting range of the LED, so as to make the illuminance of different areas more uniform.
Yet another aspect of the present invention provides an illumination apparatus. In accordance with one embodiment of the present invention, the illumination apparatus includes a tube, a substrate, at least one light source and an optical diffuser. The tube includes a lampshade and a heat dissipation base. The lampshade and the heat dissipation base form a lamp chamber. The substrate is contained in the lamp chamber. The light source is disposed on the substrate. The optical diffuser is contained in the lamp chamber to increase the emitting range of the light source, so as to make the illuminance of different areas more uniform.
It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed.
The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows:
Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
It is noted that the term “orthogonally passes” refers that the light beam perpendicularly passes through an interface without refraction.
Further, as shown in
Referring back to
In some embodiments, the chord length W and the chord height h of the light outgoing curved surface 120 are greater than the diameter of curvature d of the light incident curved surface 110. In other words, the size of the light outgoing curved surface 120 is greater than the light incident curved surface 110 and is positioned beyond the light incident curved surface 110, so that the light beams emitted by the light source 200 passes through the light incident curved surface 110 prior than passing through the light outgoing curved surface 120. Preferably, the chord length W of the light outgoing curved surface 120 ranges from about twice to 4 times the diameter of curvature d of the light incident curved surface 110. The chord height h of the light outgoing curved surface 120 ranges from about 1.25 times to twice of the diameter of curvature d of the light incident curved surface 110.
In some embodiments, the diameter of curvature d of the light incident curved surface 110 is not less than the length L of the light source 200. In other words, the light incident curved surface 110 is wider than the light source 200 for ensuring all light beams emitted by the light source 200 can pass through the light incident curved surface 110 and gets into the optical diffuser 100. Preferably, the diameter of curvature d of the light incident curved surface 110 is greater than 1.1 times the length L of the light source 200.
In some embodiments, the light incident curved surface 110 is a hemispherical surface. Because the center of curvature 112 of the light incident curved surface 110 is positioned on the center of the light emitting surface 210 of the light source 200, all the light beams emitted by the light source 200 along various directions can orthogonally pass through the light incident curved surface 110.
In some embodiments, the rim 124 of the light outgoing curved surface 120 is at the same height as that of the rim 114 of the light incident curved surface 110. The optical diffuser 100 includes a bottom surface 130, which is formed between the rim 124 of the light outgoing curved surface 120 and the rim 114 of the light incident curved surface 110. Because the rim 124 and the rim 114 are at the same height, the bottom surface 130 of the optical diffuser 100 is parallel to the light emitting surface 210.
In some embodiments, the number of the at least one light source 200 is plural, and the light sources 200 are arranged on the substrate 400 along the lengthwise direction of the tube 300, and the optical diffuser 100 extends along the direction that the light sources 200 are arranged. Specifically, the tube 300 is a circular tube, and the substrate 400 is a rectangular plate parallel to the lengthwise direction of the tube 300. The light sources 200 are arranged along the lengthwise direction of the rectangular plate.
The opposite surfaces of the substrate 400 respectively contacts the light source 200 and the heat dissipation base 320, so the thermal energy generated by the light source 200 is transferred to the heat dissipation base 320 via the substrate 400 by thermal conduction, and then, the heat dissipation base 320 dissipates the thermal energy to the environment.
The optical diffuser 100 is positioned on the heat dissipation base 320 and covers the light source 200. In other words, the optical diffuser 100 is positioned above the light emitting surfaces 210 of the light sources 200, so as to enable the light beams emitted from the light emitting surfaces 210 of the light sources 200 passing through the light incident curved surface 110 and the light outgoing curved surface 120 of the optical diffuser 100. The light path passing through the optical diffuser 100 refers to
Referring back to
In some embodiments, the distance H between the light emitting surface 210 (See
In some embodiments, the heat dissipation base 320 comprises a cavity 326. In other words, the heat dissipation base 320 is a hollow structure. Referring to
Referring to
In some embodiments, the lampshade 310 and the optical diffuser 100 can be formed by the light transmissive material such as, for example, Polymethylmethacrylate (PMMA, or named Acrylic). But the material is not limited to PMMA.
In some embodiments, the light source 200 is a LED. The LED can be, but is not limited to be, a LED package or a LED chip. The LED can be, but is not limited to be, a white LED, a red LED, a green LED, or a blue LED.
In accordance with another embodiment of the present invention, an illumination module is disclosed, which includes a light source 200 and an optical diffuser 100. The light source 200 is a LED, and the optical diffuser 100 is positioned above the LED to increase the emitting range of the LED, so as to make the illuminance of different areas more uniform.
Although the present invention has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.
Number | Date | Country | Kind |
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101130669 | Aug 2012 | TW | national |