According to research by Sigmund Freud, we suppress our darkest desires, our deepest thoughts because they are not acceptable, not something society wants to hear. We do not realise we do it, it is an unconscious action. The Id wants something, a life sustaining activity, breathing, eating, sex and the ego tries to satisfy this need in an acceptable way. The libidinal instincts are still repressed however, the energy still forced to hide. But during sleep, the ego is relaxed, the power struggle is reversed, the Id stronger than the ego. Unconscious thoughts from the Id filter through to the conscious in the form of dreams. Our desires are exposed, the secrets are out, flashing through our minds. This is all in the confines our bed, a place where we isolate ourselves, where we dream, where we breathe and have sex. Where the unconscious becomes conscious and we get a glimpse into our own psyche.
Infrared light is in the world around us. However we cannot see it. Like our unconscious thoughts Infrared is there but inaccessible unless there is an infrared filter to see, much like a bed when we dream. Thus, the light, like our deepest desires, is suppressed, forced to be unseen by our eye.