The present invention relates to a diffusion structure, and more particularly to a diffusion structure for use in a lighting device.
In recent years, light emitting diodes (LEDs) are widely used in daily lives because of many benefits and advantages such as power-saving efficacy. Until now, LEDs are widely used in many electronic devices such as display devices, household electrical appliances, vehicle electronic components, lighting devices, and the like. Take a household lighting device using the LED as the lighting device for example. In comparison with the conventional incandescent lights and fluorescent lamps, LED has shorter warm-up time, quicker response speed, smaller size, longer life, higher power-saving efficacy, better shock resistance, lower contamination, higher reliability and higher productivity. With the maturity of the LED technology, LEDs will replace the conventional incandescent lights and fluorescent lamps.
In comparison with the conventional light source, LED has higher directivity. Due to the good directivity, when plural LEDs are enabled to emit light beams simultaneously, the user usually feels that the light beams are from plural “points”. Under this circumstance, the user usually feels uncomfortable. For solving this problem, the lighting device using LEDs as the light sources is usually equipped with a diffusion plate. The light beams from all LEDs are firstly incident to the diffusion plate and then outputted to the surroundings. Since plural microstructures, frosted structures, diffusion powder (such as titanium dioxide) or irregular particles are formed on the surface of the diffusion plate, the lighting device has the “planar” lighting efficacy. The “planar” lighting efficacy of using the diffusion plate is well-known in the art, and is not redundantly described herein.
Nowadays, the manufacturers pay much attention to the performance development of the diffusion plates according to two mainstream aspirations. The first aspiration is related to the transmittance of the diffusion plate, i.e. the capability of allowing the light beams from the LED to penetrate through the diffusion plate. The transmittance of the diffusion plate has an influence on the luminance provided by the lighting device. The second aspiration is related to the haze of the diffusion plate, i.e. the capability of converting the “point” illumination to the “planar” illumination. However, for most of the current diffusion plates, the transmittance is negatively correlated with the haze. It is very difficult to increase the transmittance and the haze simultaneously. Moreover, for most of the current diffusion plates, the light diffusion angle is usually restricted to be smaller than 120 degrees. As known, the structure and fabricating process of the current diffusion plate are not effective to increase the light diffusion angle.
Therefore, there is a need of providing an approach to improve the diffusion plate.
The present invention relates to a diffusion structure, and more particularly to a diffusion structure with high transmittance, high haze and wide light diffusion angle.
The present invention further provides a lighting device with such a diffusion structure.
In accordance with an aspect of the present invention, there is provided a lighting device. The lighting device includes at least one LED unit and a diffusion structure. The at least one LED unit is used for emitting plural light beams. The diffusion structure is arranged in a transmission path of the plural light beams. The diffusion structure includes a grating layer and a speckle layer. The plural light beams are sequentially transmitted through the grating layer and the speckle layer and then outputted to surroundings.
In an embodiment, the grating layer is arranged between the at least one LED unit and the speckle layer.
In an embodiment, the speckle layer and the grating layer are formed on a first surface and a second surface of the diffusion structure, respectively.
In an embodiment, the grating layer includes plural gratings, which are partially or entirely distributed over the second surface, wherein any two of the gratings have an identical grating parameter set or different grating parameter sets.
In an embodiment, the grating parameter set includes at least one of a grating depth, a grating pitch, a grating duty cycle and a grating orientation. After the plural light beams are transmitted through the speckle layer and then outputted to surroundings, the plural light beams collectively result in a light pattern. In addition, the light pattern is determined according to the grating parameter sets of the plural grating and/or a distribution status of the plural gratings.
In an embodiment, the speckle layer further includes at least one functional region and the at least one functional region has a specified profile without any speckle, or the speckle layer is partially or entirely distributed over the first surface and at least comprises plural speckles. The plural speckles are continuously distributed over the first surface, or the plural speckles are discontinuously distributed over the first surface, or the plural speckles are distributed as a specified profile, wherein any two of the plural speckles have an identical intensity, or any two of the plural speckles have different intensities.
In an embodiment, the grating layer is formed on the diffusion structure by at least one of a holographic lithography technology, an electronic etching technology, a laser beam writing technology, a phase mask lithography technology, a micro-molding technology and a holographic technology.
In an embodiment, the lighting device is a bottom-lighting type lighting device.
In an embodiment, the lighting device further includes a lateral light source processing module and a light guide module. At least one saw-toothed structure is formed on a second surface of the lateral light source processing module. In addition, an included angle between a surface of the at least one saw-toothed structure and a normal line perpendicular to a first surface of the lateral light source processing module is a specified angle. When at least one light beam is projected on the at least one saw-toothed structure, the at least one light beam is reflected by the at least one saw-toothed structure and propagated along a specified direction, so that the at least one light beam is transmitted through the first surface of the lateral light source processing module and directed to the diffusion structure. The light guide module is arranged between the at least one LED unit and the lateral light source processing module, or the at least one LED unit is arranged between the lateral light source processing module and the light guide module. In addition, at least one of the plural light beams from the at least one LED unit is guided to the at least one saw-toothed structure by the light guide module.
In an embodiment, the specified angle is in a range between 40 degrees and 45 degrees.
In an embodiment, the diffusion structure further includes an image piece, and the speckle layer is arranged between the grating layer and the image piece. The plural light beams from the at least one LED unit are sequentially transmitted through the grating layer, the speckle layer and the image piece and then outputted to surroundings.
In accordance with another aspect of the present invention, there is provided a diffusion structure for uniformly diffusing plural light beams and outputting the plural light beams to surroundings. The diffusion structure includes a first surface and a second surface. The second surface opposed to the first surface. A speckle layer is formed on the first surface. A grating layer is formed on the second surface. The grating layer is arranged between a light source and the speckle layer, so that the plural light beams emitted by the light source are sequentially transmitted through the grating layer and the speckle layer and then outputted to surroundings.
In an embodiment, the grating layer includes plural gratings, which are partially or entirely distributed over the second surface, wherein any two of the gratings have an identical grating parameter set or different grating parameter sets.
In an embodiment, the grating parameter set includes at least one of a grating depth, a grating pitch, a grating duty cycle and a grating orientation. After the plural light beams are transmitted through the speckle layer and then outputted to surroundings, the plural light beams collectively result in a light pattern. In addition, the light pattern is determined according to at least one of the grating parameter sets of the plural grating and a distribution status of the plural gratings.
In an embodiment, the grating layer is formed on the diffusion structure by at least one of a holographic lithography technology, an electronic etching technology, a laser beam writing technology, a phase mask lithography technology, a micro-molding technology and a holographic technology.
In an embodiment, the speckle layer further includes at least one functional region and the at least one functional region has a specified profile without any speckle, or the speckle layer is partially or entirely distributed over the first surface and at least comprises plural speckles. The plural speckles are continuously distributed over the first surface, or the plural speckles are discontinuously distributed over the first surface, or the plural speckles are distributed as a specified profile, wherein any two of the plural speckles have an identical intensity, or any two of the plural speckles have different intensities.
In an embodiment, the diffusion structure is included in an indoor lighting device, an outdoor lighting device, a display device, a backlight module or a projecting device, or the light source comprises at least one LED unit.
In an embodiment, the indoor lighting device or the outdoor lighting device includes a lateral light source processing module and a light guide module. At least one saw-toothed structure is formed on a second surface of the lateral light source processing module. In addition, an included angle between a surface of the at least one saw-toothed structure and a normal line perpendicular to a first surface of the lateral light source processing module is a specified angle. When at least one light beam is projected on the at least one saw-toothed structure, the at least one light beam is reflected by the at least one saw-toothed structure and propagated along a specified direction, so that the at least one light beam is transmitted through the first surface of the lateral light source processing module and directed to the diffusion structure. The light guide module is arranged between the at least one LED unit and the lateral light source processing module, or the at least one LED unit is arranged between the lateral light source processing module and the light guide module. In addition, at least one of the plural light beams from the at least one LED unit is guided to the at least one saw-toothed structure by the light guide module.
In an embodiment, the specified angle is in a range between 40 degrees and 45 degrees.
In an embodiment, the diffusion structure further includes an image piece. The speckle layer is arranged between the grating layer and the image piece. The plural light beams from the light source are sequentially transmitted through the grating layer, the speckle layer and the image piece and then outputted to surroundings.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
Moreover, the grating layer 14 comprises plural gratings, and the speckle layer 13 comprises plural speckles. In a preferred embodiment, the speckles are distributed over the entire first surface 11, and the gratings are distributed over the entire second surface 12. The ways of distributing the speckles and the gratins are presented herein for purpose of illustration and description only. However, those skilled in the art will readily observe that numerous modifications and alterations may be made according to the practical requirements. For example, the speckles may be only distributed over a part of first surface 11, and the gratings may be only distributed over a part of the second surface 12. Moreover, the gratings or the speckles may be distributed in a continuous or discontinuous manner.
Furthermore, the grating layer 14 may be formed on the diffusion structure 1 by any one of a holographic lithography technology, an electronic etching technology, a laser beam writing technology, a phase mask lithography technology, a micro-molding technology and a holographic technology.
In this embodiment, the main body 1 of the diffusion structure 1 is a flat plate. The light source 9 is composed of plural light emitting diode units (not shown). Alternatively, the light source 9 is composed of plural laser units (not shown). Moreover, in this embodiment, the light source 9 is a bottom-lighting type light source for directly projecting the plural light beams L1 to the diffusion structure 1. The light source is presented herein for purpose of illustration and description only. However, those skilled in the art will readily observe that numerous modifications and alterations may be made according to the practical requirements.
The spirits and diffusing principles of the diffusion structure of the present invention will be illustrated as follows. When the plural light beams L1 emitted by the light source 9 are projected on the grating layer 14, the plural light beams L1 are diffracted and scattered by the gratings of the grating layer 14. Under this circumstance, the original plural “point” light sources formed by the plural light beams L1 are converted into more “point” light sources. Consequently, after these light beams L1 are transmitted through the grating layer 14, the overall light beams L1 exhibits a visual effect like a start-studded sky. In other words, these “point” light sources are collaboratively defined as a “planar” light source.
However, since these light beams L1 are subject to color dispersion on the gratings of the grating layer 14, the visual effect like the start-studded sky is a polychromatic effect (e.g. a rainbow-like colorful effect). After the colors of the light beams L1 are dispersed, the color-dispersed light beams L1 are projected to the speckle layer 13. The speckles of the speckle layer 13 provide a function of mixing the color-dispersed light beams L1. Consequently, the light beams outputted to the surroundings are uniformly mixed white light.
It is noted that each grating of the grating layer 14 has a corresponding grating parameter set. The grating parameter set includes at least one of a grating depth, a grating pitch, a grating duty cycle and a grating orientation. By controlling the grating parameter set of each grating of the diffusion structure 1, the light diffusion angle, the diffusion area, the light pattern and the light diffraction efficiency are adjustable.
Hereinafter, the distribution of plural point light sources formed by a single point light source in response to plural gratings will be illustrated with reference to
Moreover, by controlling the grating parameter set of each grating and/or controlling the distribution status of these gratings, after the plural light beams are transmitted through the grating layer, the plural light beams are interfered with each other to collectively result in a light pattern.
Hereinafter, the light pattern resulted from the interference of plural light beams that are transmitted through the grating layer will be illustrated with reference to
Consequently, those skilled in the art will readily observe that the grating layer 14 may be designed according to the practical specification requirements of the diffusion structure 1. That is, any two gratings of the grating layer 14 may have an identical grating parameter set or different grating parameter sets.
Moreover, by controlling the roughness of the first surface 11 of the diffusion structure 1, the speckle intensity of the speckle layer 13 is changed, so that the light mixing effect of the speckle layer 13 is adjustable. That is, any two speckles of the speckle layer 13 may have the identical speckle intensity or different speckle intensities.
From the above discussions, for the diffusion structure 1 of the present invention, the transmittance is 80%, the haze is 100%, and the light diffraction angle θ1 is 170. Since the diffusion structure 1 of the present invention is effective to solve the drawbacks of the conventional diffusion structure, the diffusion structure 1 of the present invention has industrial usefulness in the lighting technology. For example, the diffusion structure 1 of the present invention may be applied to a lighting device such as a wall lamp, an advertising lamp, a lamp cover, or the like. Alternatively, the diffusion structure 1 of the present invention may be applied to a backlight module (e.g. a LCD display device) or a projecting device.
Moreover, as shown in
In this embodiment, the included angle θ2 is a specified angle. The specified angle is in the range between 40 degrees and 45 degrees. Consequently, when the plural light beams L2 emitted by the plural LED units 91 are projected on any saw-toothed structure 311, the plural light beams L2 are reflected by the saw-toothed structures 311, then transmitted through the second surface of the lateral light source processing module 31, and finally directed to the grating layer 14 of the diffusion structure 1.
Since the functional region 131 has no any speckle, the functional region 131 fails to provide the light mixing function. Under this circumstance, the specified profile (e.g. “LOGO”) exhibits the rainbow-like colorful effect. Moreover, since the region of the speckle layer 13′ excluding the specified profile (e.g. “LOGO”) has the speckles to provide the light mixing function, the light beams outputted from the region of the speckle layer 13′ excluding the specified profile (e.g. “LOGO”) are uniformly mixed white light.
It is noted that numerous modifications and alterations may be made while retaining the teachings of the second embodiment. For example, the diffusion structure with the speckle layer including the functional region may be applied to the bottom-lighting type lighting device or the lateral-lighting type lighting device.
Since the region of the speckle layer 13″ with the specified profile (e.g. “LOGO”) has the speckles to provide the light mixing function, the light beams outputted from the speckle layer 13″ are uniformly mixed white light. Moreover, since the region of the first surface 11 excluding the specified profile (e.g. “LOGO”) has no any speckle, the light mixing function fails to be provided. Under this circumstance, the region of the first surface 11 excluding the specified profile (e.g. “LOGO”) exhibits the rainbow-like colorful effect.
It is noted that numerous modifications and alterations may be made while retaining the teachings of the third embodiment. For example, the diffusion structure with the speckle layer distributed over a part of the first surface may be applied to the bottom-lighting type lighting device or the lateral-lighting type lighting device.
From the second embodiment and the third embodiment, by the diffusion structure 1 of the present invention, a specified region or a specified profile can attract people's attention in different ways or color effects. As a consequence, the diffusion structure of the present invention can provide an advertising effect or a special effect.
It is noted that numerous modifications and alterations may be made while retaining the teachings of the fourth embodiment. For example, the diffusion structure with the image piece may be applied to the bottom-lighting type lighting device or the lateral-lighting type lighting device.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
Number | Date | Country | Kind |
---|---|---|---|
101113344 | Apr 2012 | TW | national |