Light problem

[Borax]

I wont to create light model, which lighten area shaped as a cone. You can see it better in the picture.

But there is a problem, because in game, it looks very strange and you can see tiles, whih are not constant light.

I have created this model from 15 light sources (maybe, there is the problem, because the lights are overlaying). I need this model as an attachment, so I cant create the cone shape from normal light sources.