Light guide plate having uniform light emission and manufacturing method thereof

A light guide plate includes a main body and a number of micro protrusions. The main body includes a light emitting surface, a bottom surface, and a light incident surface. The bottom surface is opposite to the light emitting surface. The light incident surface connects the light emitting surface and the bottom surface. The protrusions are randomly positioned on the light emitting surface, and are used for reflecting light rays towards random directions.

BACKGROUND

1. Technical Field

The present disclosure relates to a light guide plate having uniform light emission and a method of manufacturing the light guide plate.

2. Description of Related Art

A light guide plate usually distributes a number of microstructures. However, the microstructures are arranged in order, and thus light rays transmitted in the light guide plate can be reflected by the microstructures towards a same direction, and a portion of the light emitting surface emits more light rays, and the other portion of the light emitting surface emits less light rays. The overall brightness of the light emitting surface is not uniform.

Therefore, it is desirable to provide a light guide plate and a manufacturing method thereof that can overcome the above-mentioned limitations.

DETAILED DESCRIPTION

FIG. 1illustrates a light guide plate100in accordance with an embodiment. The light guide plate100includes a main body10and a number of micro protrusions20. In the embodiment, the micro protrusions20and the main body10are made of the same material.

The main body10is substantially cubic, and is made of transparent material (such as acrylic resin or polyethylene resin). The main body10includes a light emitting surface11, a bottom surface13, a light incident surface15, and a side surface17. The bottom surface13is opposite to and substantially parallel to the light emitting surface11. The side surface17is opposite to and substantially parallel to the light incident surface15. The light incident surface15is substantially perpendicular to the light emitting surface11. In other embodiments, the bottom surface13can be inclined with respect to the light emitting surface15.

A number of light sources30face the light incident surface15, and emit light rays. The light incident surface15transmits the light rays into the light guide plate100. The bottom surface13and the side surface17respectively internally reflect the light rays in the light guide plate10. The light emitting surface11transmits a portion of the light rays incident thereon to the exterior above the light guide plate100, and reflects the other portion of the light rays incident thereon back into the light guide plate100.

Also referring toFIG. 2, the bottom surface13uniformly distributes a number of micro recesses130. When the light rays transmitted in the light guide plate100arrive at the micro grooves130, the light rays can be directly reflected by the surfaces of the micro grooves130directly to the light emitting surface11. Thus the transmitting paths of the light rays in the light guide plate100are shorter, and the energy loss of the light rays is reduced. Accordingly, the light brightness of the light emitting surface11is greatly improved. In the embodiment, the micro recesses130are spherical crown-shaped, and are arranged in an array of rows and columns. A ratio of the diameter D of each micro recess130to the depth H of each micro recess130is about 10:1. In other embodiments, the micro recesses130also can be cylindrical or cubic, and are formed through a laser processing method.

The micro protrusions20are randomly positioned on the light emitting surface11The shapes and the areas of the micro protrusions20are randomly distributed, and thus the light rays transmitted in the light guide plate100can be randomly reflected towards different directions, and randomly reach different portions of the light emitting surface11. Therefore, the densities of the light rays at different portions of the light emitting surface11are substantially equal as each other, and the brightness of the light emitting surface11is distributed uniformly. In the embodiment, the protrusions20are formed through a high pressure spraying method.

FIG. 3shows a method of manufacturing the light guide plate100, and the method includes the following steps.

In step S1, a main body10is provided, and the main body10has a light emitting surface11and a bottom surface13opposite to the light emitting surface11.

In step S2, a laser processing device300is provided, and a number of the micro recesses130are uniformly formed on the bottom surface13using the laser processing device300. In this embodiment, the micro recesses130are spherical crown-shaped, and are arranged in an array of rows and columns.

In step S3, a high pressure spraying device200is provided, and a number of the micro protrusions20are randomly formed on the light emitting surface11using the high pressure spraying device200. In particular, the high pressure spraying device200includes a hollow working container210, a solvent inlet220, a gas inlet230, and a nozzle240. The solvent inlet220, the gas inlet230, and the nozzle240communicate with the working container210. A molten solvent is poured into the working container210through the solvent inlet220. A high pressure gas enters into the working container210through the gas inlet230. The nozzle240faces the light emitting surface11, and is separated from the light emitting surface11, and sprays the molten solvent on the light emitting surface11at a force of the high pressure gas, thus forming a number of micro protrusions20randomly. The shapes and the areas of the micro protrusion20are randomly formed. At last, the micro protrusions20are cooled to be attached to the light emitting surface11, and thus the light guide plate100is obtained.

If a spraying area of the nozzle240is greater than the area of the light emitting surface11, then the nozzle240does not move during the high pressure spraying process. If the spraying area of the nozzle240is less than the area of the light emitting surface11, then the nozzle240needs to move during the high pressure spraying process to make the spraying area to cover the light emitting surface11.