the light reflection face 110 of the light guiding plate 700 referring to fig1 a a thick photoresist film or photosensitive film 420 is formed on a base substrate 410 by a spin coating method after that as shown in fig1 b a micro lens 430 for concentrating an incident light is aligned over the photoresist film 420 thereafter the light generated from a light source 440 is emitted onto the micro lens 430 to pass through the micro lens 430 then the light passing through the micro lens 430 is irradiated onto the photoresist film 420 to partially expose the photoresist film 420 to the light the light passing through the micro lens 430 has a quadrangular pyramid shape whose area decreases gradually as it goes from the micro lens 430 to a focused portion of the photoresist film 420 thus the photoresist film 420 is exposed to have the same profile as the light irradiated onto the micro lens 430 subsequently as shown in fig1 c the exposed photoresist film 420 is developed and thus a photoresist recess pattern 425 having the same profile as the brightness enhancement recess 112 is formed afterwards as shown in fig1 d a metal layer 432 is deposited on the patterned photoresist film including the photoresist recess pattern 425 to a certain thickness by a sputtering method the deposited metal layer 432 serves as a metal substrate having a metal protrusion 435 corresponding to the photoresist.