A projection television has a screen with a three dimensional hologram on a film substrate for collecting light over a range of incident angles and redirecting the light more nearly forward. The display unit includes a drive panel and a sealing panel that face each other with a middle layer in between. Tangents of ends of the oil collision part are made acute angle to smoothen the flow of the refrigerant. A control unit controls the amount of air blasted by the second air-blower, according to the amount of air blasted by the first air-blower. Also disclosed are methods of preparing the compounds of formula, intermediates therefor and their utility in treating a variety of disease conditions. The fans are arranged in a hybrid serial parallel configuration which provides both redundant flow of successive fans and the ability to flow around a failed or locked fan to continue airflow.