Abstract: A housing (17) that accommodates a light source (1), a display device (3), etc. has an intake aperture (18) and an exhaust aperture (24). A blowing unit (16, 23) sucks air in through the intake aperture and expels air out through the exhaust aperture. A filter unit (19) is disposed so that a filter (20) faces the intake aperture in a predetermined area between a rolling shaft (31a) and a take-up shaft (31b). A part of the filter facing the intake aperture is renewed by taking-up the filter from the rolling shaft onto the take-up shaft. A control unit (36) performs control so as to renew the filter for a range that is smaller than an opening area of the intake aperture, when a predetermined renewal condition is determined to be satisfied, based on the output of a detection unit (38, 39a, 39b) that detects a specific factor value relating to contamination of the filter, such as a cumulative display time, a temperature, an air pressure, etc.

Abstract: A housing (17) that accommodates a light source (1), a display device (3), etc. has an intake aperture (18) and an exhaust aperture (24). A blowing unit (16, 23) sucks air in through the intake aperture and expels air out through the exhaust aperture. A filter unit (19) is disposed so that a filter (20) faces the intake aperture in a predetermined area between a rolling shaft (31a) and a take-up shaft (31b). A part of the filter facing the intake aperture is renewed by taking-up the filter from the rolling shaft onto the take-up shaft. A control unit (36) performs control so as to renew the filter for a range that is smaller than an opening area of the intake aperture, when a predetermined renewal condition is determined to be satisfied, based on the output of a detection unit (38, 39a, 39b) that detects a specific factor value relating to contamination of the filter, such as a cumulative display time, a temperature, an air pressure, etc.

Abstract: In a digital signal recording and reproducing apparatus, digital input data is transmitted in a transmission packet format and is recorded in a recording packet format. In a recording stage, an auxiliary signal generator (3) generates an auxiliary signal for special reproduction in the transmission packet format, and the digital and auxiliary signals are converted into respective recording packets by means of recording signal converters (5, 6). Recording means (9, 10) performs a specific recording process on the recording packets and an identification signal for identifying between the recording packets of the digital signal and of the auxiliary signal. While in a reproducing stage, reproduction signal processing means (14, 15) performs a specific reproduction process on the reproduction signal to thereby reconstruct the recording packets and the identification signal.