Dual or multi-modulation display system are disclosed that comprise projector systems with at least one modulator that may employ non-mechanical beam steering modulation. Many embodiments disclosed herein employ a non-mechanical beam steering and/or polarizer to provide for a highlights modulator.

A method for operating a discharge lamp by modulating a current signal is presented. The discharge lamp is operated with at least two different frequencies. At first a probability distribution function for a first number of first frequency periods and a second number of second frequency periods is defined. Next, the first number of first frequency periods and the second number of second frequency periods are determined depending on the probability distribution function by at least one random number. The current signal is modulated by applying the first number of first frequency periods and the second number of second frequency periods to the current signal for operating the discharge lamp.

The invention describes a method for operating a discharge lamp by adapting a current signal. A distribution function is defined for gathering several time span values that define several different time spans. The several time span values are determined depending on the distribution function by one or more random numbers. The current signal is commutated at every instant of time according to an expiry of each of the several time spans. A light apparatus is provided with a control unit to perform any method.

An image projection apparatus includes: a light source; an image display element including multiple micromirrors arranged in two dimensions, the multiple micromirrors forming an image display plane, each micromirror having a reflecting surface; and a projection optical system. Conditional expressions (1) and (2) below are satisfied:
θ1≥14(deg)  (1)
1.2<BF/L<2.2  (2) where θ1 is a maximum tilt angle of the reflecting surface of each micromirror with respect to the image display plane, L is a diagonal length of the image display plane, and BF is a distance between a vertex of a lens within the projection optical system and closest to the image display plane and the image display plane along an optical axis of the projection optical system.

A light source apparatus includes a light source, a light source enclosure that accommodates the light source and has a plurality of openings formed therein in a circumferential direction around an optical axis of the light source, a channel having an introduction port through which air is introduced from outside of the light source enclosure, the channel allowed to communicate with the plurality of openings, and an opening/closing mechanism that rotates around the optical axis to selectively open and close the plurality of openings, and the opening/closing mechanism has an opening/closing section that opens and closes the plurality of openings in a first posture in which the optical axis extends along a horizontal plane in such a way that upper openings located on a vertically upper side are open and at least part of lower openings located on a vertically lower side is closed.

Dual or multi-modulation display system are disclosed that comprise projector systems with at least one modulator that may employ non-mechanical beam steering modulation. Many embodiments disclosed herein employ a non-mechanical beam steering and/or polarizer to provide for a highlights modulator.

A projection device for projecting at least one image onto a projection surface is provided. According to the present disclosure, a control device of the projection device is designed, on the basis of an evaluation of at least one measured value of a measuring device of the projection device determined during a drive of a discharge lamp of the projection device with a current waveform to be checked, to check the current waveform in respect of its suitability for minimizing an electrode burn-back of a first electrode and a second electrode, and in the case of a positive check result, to retain the checked current waveform, and in the case of a negative check result, depending on a checked commutation vector characterizing the checked current waveform, to create, by means of a specifiable algorithm, a modified commutation vector that characterizes a modified current waveform.

A discharge lamp driving device includes a discharge lamp driving unit configured to supply a driving current to a discharge lamp, and a control unit configured to control the discharge lamp driving unit. The discharge lamp driving device is configured to provide a first hybrid period and a second hybrid period each alternately including a first AC period in which an AC current is supplied and a first DC period in which a DC current with a first polarity is supplied. The control unit, in the first hybrid period, is configured to change a ratio of length of the first DC period to length of the first AC period to be increased, and in the second hybrid period, is configured to change a ratio of the length of the first AC period to the length of the first DC period to be increased.

An image projection apparatus includes a light source configured to emit light with a luminance according to electric power; a color wheel configured to sequentially transmit the light through multiple color filters arranged along a circumferential direction; a light modulation element configured to form an image by modulating an intensity of the light transmitted through the color wheel according to an input signal representing input image data; and a selection controller configured to select, out of a first waveform indicating temporal change in electric power supplied to the light source in a first mode and a second waveform indicating temporal change in electric power supplied to the light source in a second mode, the second waveform when a luminance value of the input signal is equal to or less than a first threshold. A brightness of the image in the second mode is lower than that in the first mode.

A discharge lamp driving device includes a discharge lamp driving unit configured to supply a driving current to a discharge lamp including electrodes, a controller configured to control the discharge lamp driving unit, and a voltage detection unit configured to detect an inter-electrode voltage of the discharge lamp, in which the controller controls the discharge lamp driving unit so that the driving current includes a hybrid period in which a first period for supplying an AC current with a first frequency to the discharge lamp and a second period for supplying a DC current to the discharge lamp are alternately repeated, in which the first frequency includes a plurality of different frequencies, and in which the controller changes the first frequency on the basis of at least one of the detected inter-electrode voltage and driving power supplied to the discharge lamp.