Light source device, projector, and method of driving discharge lamp

Abstract

The invention provides a light source device, a projector, and a method of driving a discharge lamp while suppressing the blackening of the discharge lamp, and keeping the inter-electrode distance within a allowable distance range. A light source device includes a discharge lamp having a light emitting case and a pair of electrodes, a drive device, a voltage detector, and a time measurement device, the drive device alternately repeats a first alternating current supply interval and a second alternating current supply interval, measures a period of the first and the second alternating current supply interval with the time measurement device, performs a change from the first alternating current supply interval to the second alternating current supply interval when the period of the first alternating current supply interval reaches a predetermined period A, and performs a change from the second alternating current supply interval to the first alternating current supply interval when the period of the second alternating current supply interval reaches a predetermined period B, or when an absolute value of an inter-electrode voltage of the pair of electrodes reaches a threshold value.

Description

technical field [0001] The present invention relates to a light source device, a driving method of a discharge lamp, and a projector. Background technique [0002] As the light source of the projector, discharge lamps (discharge lamps) such as high-pressure mercury lamps and / or metal halide lamps are used. [0003] Such a discharge lamp is driven, for example, by a driving method in which a high-frequency alternating current is supplied as a driving current (for example, refer to Patent Document 1). With this driving method, discharge stability can be obtained, blackening and / or devitrification of the discharge lamp main body can be prevented, and a reduction in the lifetime of the discharge lamp can be suppressed. [0004] However, in this driving method, arc discharge occurs between a pair of electrodes during lighting of the discharge lamp, and since the electrodes become high temperature, the electrodes melt and the gap between the electrodes gradually expands. [0005...

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Problems solved by technology

[0009] However, in the lighting device described in Patent Document 3, the frequencies of the steady-state lighting frequency alternating current and the low-frequency alternating current are too small, and blackening and / or devitrification of the discharge lamp body may occur, resulting in discharge Lamp life is reduced by this problem

In addition, during the lighting of the discharge lamp, although protrusions are formed on the front ends of the pair of electrodes, the electrodes are gradually consumed during a long period of time, such as hundreds or thousands of hours of lighting, so that the protrusions cannot be enlarged to Scheduled size

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