Patent Application
20090168441
1. Technical Field
The present invention generally relates to illumination devices, particularly to a car having such an illumination device.
2. Description of related art
Illumination devices with Light emitting diodes (LEDs) as a light source typically include a lamp cover, LEDs, and a lamp holder. The LEDs are located inside the lamp cover and has two electrodes extending out of a head of the lamp cover with attached led wires. The lamp cover head is then placed in a machine for injection, forming a lamp holder within which the lamp cover head and the led wires are tightly enclosed. Manufacturing an illumination device with the LED light sources in this manner is relatively difficult and complicated. Additionally, if the LED or the lamp cover breaks, a tool is generally required to open the lamp holder to replace the broken part. The lamp holder must then be injected again. Therefore, waste is unavoidable as the illumination device is difficult to detach and accordingly the cost is high.
Therefore, there is a need for providing an illumination device which can overcome the above-mentioned problems.
The present invention relates to an illumination device. According to a preferred embodiment of the present invention, the illumination device includes a light emitting module and a mounting housing. The light emitting module includes a light guide plate. The light guide plate has a light exit surface and a light source optically coupled to the light guide plate. The mounting housing includes a top plate, an opposite mounting plate and a peripheral side plate interconnected between the top plate and the mounting plate. The top plate, the mounting plate and the side plate cooperatively defines a receiving space for receiving the light emitting module therein. A gap is defined in the top plate above the light emitting module. An opening is defined in one end of the side plate for allowing the light emitting module to insert into the receiving space.
Other advantages and novel features of the present illumination device will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:
Reference will now be made to the drawing figures to describe the various present embodiments in detail.
Referring to
Referring to
The light emitting module 20 includes a light guide plate 21, a light source 23 including a plurality of white light emitting diodes (LEDs) 231, and a reflecting plate 25. The light guide plate 21 can be made of flexible and transparent materials including polymethylmethacrylate (PMMA), poly carbonate (PC), silicone, polyacrylate, epoxy, glass and etc. A refractive index of the light guide plate 21 is in the range from 1.4 to 1.65. The light guide plate 21 includes a substantially rectangular light exit surface 210, a bottom surface 212 opposite to the light exit surface 210, and a plurality of side surfaces 214 located between the light exit surface 210 and the bottom surface 212. The light exit surface 210 of the light guide plate 21 is preferably a rough surface so that light incident towards the light exit surface 210 can uniformly be distributed. In this embodiment, the light exit surface 210 has a plurality of micro-protruding dots formed thereon. A diameter of each of the micro-protruding dots is either equal to or less than 5 millimeter. Alternatively, the light exit surface 210 can also include a plurality of micro-recesses formed thereon. The micro-protruding dots or micro-recesses can be distributed over the entire light exit surface 210 or distributed on particular regions of the light exit surface 210.
The white LEDs 231 are optically coupled with the light guide plate 21. The white LEDs 231 are disposed at a right side surface 214 of the light guide plate 21 and are arranged along a longitudinal direction of the right side surface 214. Therefore, a linear light source is formed by the linearly arrayed white LEDs 231 on the right side surface 214 of the light guide plate 21, and the right side surface 214 of the light guide plate 21 functions as a light incident surface of the light guide plate 21. The lights emitted from the white LEDs 231 are incident into an interior of the light guide plate 21 from the right side surface 214, and are guided to spread out of the light guide plate 21 from the light exit surface 210.
The white LEDs 231 each includes one LED chip and a transparent cover covering on the LED chip. The LED chip may be a blue LED chip or a green LED chip. A layer of fluorescence material is disposed between the transparent cover and the LED chip or directly formed on the transparent cover, so that a white light can be emitted from the LED chip. For example, a blue LED chip and a yellow phosphor are adopted to generate white light. Alternatively, the white LEDs 231 each may include more than one LED chips and a transparent cover covering the LED chips. For instance, the white LEDs 231 each includes three LED chips consisting of a red LED chip, a green LED chip and a blue LED chip. The lights emitted by the three LED chips can be mixed together to obtain a white light and there is no need to dispose a fluorescence material in the LEDs 231. Further, the LEDs 231 of the linear light source are not limited to the white LEDs 231, which may include one or more monochromatic light LED chips such as orange LED chips, yellow LED chips, purple LED chips, or etc.
The reflecting plate 25 is disposed on the bottom surface 212 of the light guide plate 21 to reflect the lights incident thereon, and the lights are spread out via the light exit surface 210 of the light guide plate 21 effectively, which enhance light utilization efficiency of the light emitting module 20. A reflecting layer (not shown) is formed on an outer surface of the reflecting plate 25. The reflecting layer is made of reflective materials, such as metal, white printing ink and etc. A side of the reflecting plate 25 is larger than that of the light guide plate 21. More specifically, a right side edge of the reflecting plate 25 is protruded out of the right side surface 214 of the light guide plate 21, and located under the white LEDs 231. It is well know that a radiation angle of each of the white LEDs 231 is usually about 120°, which induces a lowest peripheral portion of the lights emitted from the white LEDs 231 to irradiate downwardly towards the right side edge of the reflecting plate 25. The lowest peripheral portion of the lights can be reflected by the right side edge of the reflecting plate 25, thus to maximize the light utilization efficiency of the light emitting module 20. Alternatively, the reflecting plate 25 can be omitted, and a reflecting layer can be coated on the bottom surface 212 of the light guide plate 21 to replace the reflecting plate 25 of the preferred embodiment. A thickness of the reflecting layer of the light guide plate 21 is preferably to be no more than 2 centimeters, so that the light guide plate 21 can be configured to have a thin configuration. Therefore, the light guide plate 21 is able to achieve high performance in light distribution while maintaining a compact size and low cost.
The white LEDs 231 are used in the light emitting module 20 due to advantages of high brightness, high luminous efficiency, good light quality, power consumption and long life-span. Referring to
Alternatively, an end cap (not shown) for blocking the opening 160 of the mounting housing 10 can be added in the illumination device. After assembling the light emitting module 20 to the mounting housing 10, the end cap is fixed on the opening 160 of the mounting housing 10 to prevent the light emitting module 20 from being disassembled from the opening 160 of the mounting housing 10.
Referring to
The working principle of the circuit will hereinafter be explained in detail. For example, the car 30 is used as the application of the illumination device. The illumination device is fixed inside of the car 30. As previously stated, the luminance of the illumination device can be changed according to usage requirements of the car 30. More specifically, when the car 30 is moving, the bidirectional switch K can be set manually to connect with the first electrical juncture 1, such that the luminance of the illumination device is adequate enough for passengers to relax such as reading in the car 30. When the car 30 is stopped, the bidirectional switch K can be set to connect with the second electrical juncture 2, such that the luminance of the illumination device is brighter and allows the pathway inside the car 30 to be clearly visible for the passengers to get on/off the car 30. When light is not required, the bidirectional switch K can be set to cut off, which is beneficial for saving electricity.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200710203460.4 | Dec 2007 | CN | national |
