In general, orchids cannot stand direct sunlight on their leaves.  However, they do require an adequate amount of light in order to grow.  Generally, you can see how much light an orchid requires by observing its leaves.

Place an orchid in a very well-lit spot in your house.  A good place would be a window facing the South.

For the majority of orchids, one should want light green leaves.  Once exposed to an adequate amount of light, the leaves will start to darken in color because of the greater production of red pigment which protects the leaves from the light.  This means that the plant is functioning well and is protecting itself from burns on its leaves.  This is the ideal situation for an orchid plant to flourish.