Abstract: Disclosed are a method of manufacturing a light guiding panel by means of carving fine engravings on a surface of a transparent substrate by plasting fine particles and an apparatus for the same. A distributed degree of the engravings gradually increases as they become far away from a light source position. In a first method, fine particles are mixed with a high-speed air and then the air-mixed fine particles are diffusively blasted through one or more blasting nozzles so that the fine particles can collide with a surface of a transparent substrate slantly. In a second method, the air-mixed fine particles are diffusively blasted through a plurality of aligned blasting nozzles so that the fine particles can perpendicularly collide with the entire width of a transparent substrate, while appropriately adjusting intervals of the blasting nozzles and/or the amount of blasting as well as swing the blasting nozzles.

Abstract: Disclosed is a light guiding plate formed with fine recesses and a backlight unit utilizing the same. There are formed on a bottom surface of a transparent acryl resin substrate a number of fine recesses, which are unable to be distinguished with the naked eye, in order to reflect on front surface of the plate a source light introduced through at least one side surface. The fine recesses are formed by means of a sandblasting process. The amount of the fine recesses jetted per unit hour is uniformly maintained. The number of sands collided into unit area per unit hour and impact energy of the sands are higher the further away from the side through the source light is introduced. Accordingly, density, average depth and average size of the recesses are gradually higher the further away from the light introduced side. Also, area, average complexity of the contour of the recesses and average complexity of the surface profile of the recesses are increased.