Seiko Epson Corporation

Keishi Kimura

Tetsuo Terashima

Kentaro Yamauchi

Takeshi Takezawa

Kazuo Okawa

Takaaki Koyama

Kenichi Shioiri

Chihiro Tsukinokizawa

A discharge lamp driving device includes: a direct-current power supply section (a power supply section) that controls a current of power to be supplied to a discharge lamp from input power, and outputs the current; a voltage detecting section that detects a lamp voltage (a drive voltage) of the discharge lamp; and a control section that controls a modulation factor of a lamp current (a drive current) on which amplitude modulation has been performed, the lamp current (the drive current) which is supplied to the discharge lamp from the direct-current power supply section (the power supply section), in accordance with the detected lamp voltage (drive voltage) of the discharge lamp.

Discharge lamp driving device, projector, and method for driving a discharge lamp

A projector according to an embodiment of the invention can measure the temperature of an object to be cooled accurately with a simple configuration and perform accurate cooling control. The projector includes a power-supply unit, a ballast unit having a ballast control circuit and a photocoupler, and a control unit. The power-supply unit includes a temperature detection element generating temperature information indicating the temperature inside the power-supply unit. The ballast control circuit controls a constant-current control circuit and the like based on the control information transmitted from the control unit via the photocoupler and transmits temperature data based on the temperature information to the control unit via the photocoupler. The control unit includes a projector control circuit performing cooling control on the power-supply unit based on the temperature data.

Method for controlling a projector including a cooling unit insulated from a power-supply unit

A projector includes: a light source; a light modulating device; a projection optical device; a lighting control device configured to control lighting of the light source and include a lighting unit; a control unit includes a storage section, a determination section, an information setting section configured to store problem related information regarding the problem in the storage section, a signal transmission section configured to indicate that the problem has occurred, and a detection unit configured to detect a driving state of the lighting control device; a control device configured to connect with the light control device and includes a main body side storage section, and an information acquisition section configured to acquire the problem related information when the problem occurrence signal is received and stores the problem related information in the main body side storage section.

Lighting control device and projector

A lamp driving device that drives a discharge lamp, includes: a start-up circuit configured to apply a start-up pulse for starting an operation of the discharge lamp; a non-volatile memory configured to store data therein; and a history recording unit configured to record an operation history of the applying of the start-up pulse that is performed by the start-up circuit in the non-volatile memory.

Device and method for driving discharge lamp, light source device, and projector that records an operation history of applied start-up pulses

A driving device for a discharge lamp includes: a discharge-lamp lighting unit that supplies an alternating current to the discharge lamp to thereby supply electric power to between two electrodes of the discharge lamp; an inter-electrode-voltage detecting unit that detects an inter-electrode voltage applied when predetermined electric power is supplied to between the two electrodes; and a power-supply-condition switching unit that switches, on the basis of the detected inter-electrode voltage, the power supply by the discharge-lamp lighting unit with a predetermined hysteresis given to the switching of the power supply conditions, wherein the power supply conditions are switched by changing at least one of a frequency of the alternating current, a duty ratio of the alternating current, a modulation pattern of the frequency, and a modulation pattern of the duty ratio.

Driving device and driving method for discharge lamp, light source device, and image display apparatus

A light source includes an arc tube having a first electrode and a second electrode that emit light by discharge between the electrodes, and a driving unit that supplies a current between the first electrode and the second electrode and can change at least a waveform of frequency and waveform of the supplied current. The driving unit can perform lighting drive of the arc tube, using a driving waveform formed by combining a first lighting waveform having a maximum current value at a part other than a half-cycle rear end of the waveform and a second lighting waveform having a maximum current value at the half-cycle rear end of the waveform.

Light source, projector, and method for driving light source

A light source includes an discharge lamp including a first electrode and a second electrode emitting light by discharge between them, a drive unit performing a steady operation which supplies steady energy to the first and second electrodes and an initial operation which supplies energy to the first and second electrodes with an operation different from the steady operation before performing the steady operation, a determination unit determining states of the discharge lamp and a data storage unit storing plural initial power feeding conditions provided corresponding to states of the discharge lamp as examples of the initial operation and plural steady power feeding conditions provided corresponding to the states of the discharge lamp as examples of the steady operation, in which the drive unit performs the initial operation in any one of conditions selected from the plural initial power feeding conditions according to a determination result by the determination unit and performs the steady operation in any one of conditions selected from the plural steady power feeding conditions according to a determination result by the determination unit.

Light source and projector

There is provided a rear projection television having a construction which facilitates replacement of a light source lamp and repair work within the body. The rear projection television includes a screen panel disposed at the front of a cabinet thereof, for receiving projection light projected from behind for image display, to thereby display an image thereon, a light source lamp removably disposed within the cabinet, for projecting the projection light, and a working door provided in the front face of the cabinet. An opening-detecting sensor detects opening of the working door and outputs an opening-detecting signal. An illumination section for replacement work disposed within the cabinet illuminates the inside of the body. The control section causes the illumination section to light when the opening-detecting signal is outputted by the opening-detecting sensor.

Rear projection television with screen panel for receiving projection light

An image display apparatus responding to diverse video signals having different display conditions includes: a frequency characteristic adjustment module that adjusts a frequency component of an analog video signal included in a supplied video signal; an A/D conversion module that converts the analog video signal adjusted by the frequency characteristic adjustment module into a digital video signal; and an image display module that displays a resulting image based on the converted digital video signal. The frequency characteristic adjustment module has: a filter unit that is capable of varying the frequency characteristic; a display condition detection unit that detects the display condition proper to the supplied video signal; and a filter control unit that controls the frequency characteristic of the filter unit according to the detected display condition. This arrangement adequately prevents deterioration of the picture quality due to quantization noise with regard to diverse signals having different display conditions, thus ensuring display of high-quality images.

Image display apparatus

An automatic keystone correction which enables even an inexperienced user to easily obtain an image corrected using the keystone distortion during a tilted projection. The projector detects varying of its elevation angle by using an elevation detecting module. When the angle stops varying, the projector determines that the elevation adjustment by the user ends, and executes auto keystone correction of the input image according to the elevation angle.

Projector executing keystone correction

A rear projection display is provided which can clearly display a display screen and enable positive recognition of acceptance of operation of a power switch while preventing increases in manufacturing costs and size of the display. A liquid crystal light valve modulates light emitted from a light source lamp to light for displaying a displayed on a screen. An auxiliary lamp higher in a rate of increase in luminance at start of illumination than the source lamp is arranged such that light from the auxiliary lamp can reach a rear surface side of the screen without passing through the liquid crystal light valve. A main control section causes the light source lamp and the auxiliary lamp to both illuminate at power on, and the auxiliary lamp to extinguish before luminance of the source lamp becomes high enough to cause the display screen to be displayed by projection.

Rear projection display

The present invention enhances picture quality of a projected image by a projector. A projector has a detachable optical filter that possesses a transmittance characteristic to weaken a green color element in the projection light. An image processing module performs the color adjustment processing by changing a look-up table stored in a memory module.

Image processing with changes of optical system of projector

Image signals of a progressive scan image are formed by arranging the image signals in each field in a normal order, even when the image signals in an interlace system are input, while a phase difference between a vertical synchronization signal and a horizontal synchronization signal is not constant. A switch sequentially selects a field memory in a field memory unit every time a vertical synchronization signal Vsync is input. In the selected field memory, a timer value of a timer, which is from an input of the vertical synchronization signal to an input of each horizontal synchronization signal, is written together with an image signal subsequent to each horizontal scanning signal. A sort processing unit reads image signals from two field memories in which the timer values and the image signals were recently written, arranges the image signals in order of the timer values corresponding to the image signals, and writes the image signals in a frame memory.

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Matsumoto, Japan

Keishi Kimura