1. Technical Field
The present disclosure relates to light guide plates, and in particular, to a light guide plate for an electronic device.
2. Description of Related Art
Many electronic devices often include illuminating assemblies for illuminating at least part of the electronic device such that the electronic device can be used as a signal or a warning device. The illuminating assembly often includes a light guide plate, which can change the path of light emitted from a light source and illuminate the desired part of the electronic device. Therefore, the light guide plate is an essential part of the illuminating assembly and needs to emit light uniformly. However, many light guide plates cannot emit uniform light.
Therefore, there is room for improvement in the art.
Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
The housing 100 includes a panel 110 and a receiving portion 120 protruding perpendicularly from the panel 110 for receiving the illuminating assembly 200. A long and narrow through hole 111 (see
The illuminating assembly 200 includes a light source 210 for emitting light, and a light guide plate 220 for converting a point light flux into a planar light flux. The light source 210 is a light emitting diode in the illustrated embodiment and in other embodiments may be a fluorescent lamp or a laser. The light guide plate 220 is substantially arch shaped. The light guide plate 220 includes two opposite arch plate surfaces 221, a first side 222, and a second side 223. The two opposite arch plate surfaces 221 are substantially parallel to each other, each plate 221 includes an arch flange 2210 and a straight flange 2212. The first side 222 is symmetrically convexly arch shaped and connects the two arch flanges 2210 of the two plate surfaces 221. The second side 223 is flat and connects the two straight flanges 2212 of the two plate surfaces 221. In the illustrated embodiment, the first side 222 is a light incident surface while the second side 223 is a light emission surface. Light from the light source 210 enters the light guide plate 220 through the light incident surface and emits from the light emission surface out through the light guide plate 220.
The first side 222 of the light guide plate 220 includes two end portions 2222 and a middle portion 2220 between the two end portions 2222 corresponding to the light source 210. Since the first side 222 is symmetrically convexly arch shaped and the middle portion 2220 corresponds to the light source 210, the distance between the light source 210 and the first side 222 gradually increases from the middle portion 2220 to each end portion 2222. In this state, light intensity of the light entering the light guide plate 220 gradually decreases from the middle portion 2220 to each end portion 2222. However, the distance between the first side 222 and the second side 223 also gradually decreases from the middle portion 2220 to each end portion 2222. This results in different light loss of the light entering the light guide plate 220 through different points of the first side 220. Overall, the light loss of the light entering the light guide plate 220 through the middle portion 2220 is greater than that of the light entering the light guide plate 220 through each end portion 2222. That is, when the light enters the light guide plate 220 through a point of the light incident surface which is near to the light source 210, the intensity of the light before entering the light guide plate 220 has increased, while the light loss in the light guide plate 220 is also increased. When the light enters the light guide plate 220 through a point of the light incident surface, which is far from the light source 210, the intensity of the light before entering the light guide plate 220 is decreased, while the light loss in the light guide plate 220 is also decreased. Therefore, the arch light guide plate 220 of the illustrated embodiment can emit uniform light.
A light uniformization structure is disposed on the light guide plate 220 for allowing the light guide plate 220 to emit light having increased uniformity. The light uniformization structure corresponds to the middle portion 2220. In the illustrated embodiment, the light uniformization structure is a through hole 226 running through the two plate surfaces 221 for reflecting a portion of the light entering the light guide plate 220 through the middle portion 2220. In the illustrated embodiment, the through hole 226 is substantially trapezoidal and includes four surfaces surrounding the through hole. A first hole surface 227 adjacent to the first side 222, a second hole surface 228 opposite to the first hole surface 227, and two side hole surfaces 229 respectively connect the first hole surface 227 and the second hole surface 228. The length of the second hole surface 228 is larger than that of the first hole surface 227. Light entering the light guide plate 220 through the middle portion 2220 is partly reflected away and refracted on the first hole surface 227 and two side hole surfaces 229, and is further partly reflected and refracted on the second hole surface 228, reducing the chance of the corresponding light reaching the second side 223. Therefore, the light guide plate 220 can emit light, which has increased uniformity.
It should be understood that the light uniformization structure is not limited to this embodiment. In other embodiments, the through hole 226 may be an arch hole. In addition, the light uniformization structure is not limited to the embodiment. In other embodiments, the light uniformization structure may not be a through hole but a blind hole or other structure used for reflecting or refracting light such as a flat plate or a mirror.
Referring to
Referring to
As shown in
With the arch light guide plate 220, the distance between the light incident surface and the light emission surface decreases as the distance between the light incident surface and the light source 210 increases, which reduces the light brightness difference of the light emission surface. Additionally, the light guide plate 220 can emit light with increased uniformity with the through hole 226 defined in the light guide plate 220. In addition, with the stopper 30 and the locking structure 400, the light guide plate 220 can tightly engage with the housing 100.
Even though information and the advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the present embodiments, the disclosure is illustrative only; and that changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the present embodiments to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Number | Date | Country | Kind |
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201110186609.9 | Jul 2011 | CN | national |