JP2005156750A - Projection type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type image display device in which a lamp can be turned on as immediately as possible after the lamp is turned off. <P>SOLUTION: Upon receiving a signal indicating power source OFF, a system control circuit 20 stops the supply of power by an image processing circuit power source 23 and the supply of power by a lamp power source 24. The system control circuit 20 then gives a lamp cooling power source 25 an instruction to supply maximum power. Consequently, the lamp cooling fan 26 rotates at the maximum output. Based upon the measurement information of a temperature sensor 27, the system control circuit 20 determines whether cooling has finished or not. When determination is made that cooling has finished, the supply of power by the lamp cooling power source 25 is stopped. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection display apparatus such as a liquid crystal projector.

As a projection-type image display device, there is known a projector in which a lamp power source and a video display circuit power source are configured separately as in a liquid crystal projector described in Patent Document 1. When a discharge lamp is used as a lamp, re-lighting after turning off the lamp power is performed after the lamp is sufficiently cooled (for example, after forced cooling of the fan for 90 seconds after the lamp is turned off) in order to extend the lamp life. It is customary.
Jinpyeong 4-72234

  By the way, when the user mistakenly performs the power-off operation, the user may immediately perform the power-on operation. Such an operation does not cause any problem in a cathode ray tube television, a direct-view type liquid crystal monitor, a plasma display, or the like. However, as described above, the lamp cannot be re-lighted immediately in the projector, and the user is expected to be dissatisfied particularly when the projector is used as a home projector.

  In view of the above circumstances, an object of the present invention is to provide a projection display apparatus that can turn on a lamp as soon as possible after the lamp is turned off.

  In order to solve the above problems, a projection display apparatus according to the present invention is a projection display apparatus for projecting an image by modulating light emitted from a lamp with a light valve and cooling the lamp. It has a cooling unit, and is configured to drive the lamp cooling unit with a cooling capacity higher than that at the time of power ON when receiving a power OFF command.

  With the above configuration, when the power OFF command is received, the lamp cooling unit cools the lamp with a higher cooling capacity than when the power is turned ON, so the time until the cooling is completed is shortened. Therefore, the lamp can be turned on as soon as possible after the lamp is turned off.

  A temperature sensor that measures the temperature of the lamp or the vicinity of the lamp may be provided, and the driving of the lamp cooling unit may be stopped when it is determined that cooling is complete based on the output of the temperature sensor. Or it is good also as providing the timer which measures progress of predetermined time from the time of receiving a power supply OFF command, and stopping the drive of the lamp cooling part when the predetermined time passes.

  As described above, according to the present invention, the lamp can be turned on as soon as possible after the lamp is turned off, and the user's dissatisfaction can be reduced.

  A liquid crystal projector according to an embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 is a view showing a three-plate liquid crystal projector of this embodiment. The lamp 1 is composed of an ultra-high pressure mercury lamp, a metal halide lamp, or the like, and the irradiation light is emitted as parallel light by a parabolic reflector and guided to the integrator lens 4.

  The integrator lens 4 is composed of a pair of lens groups (fly eye lenses) 4a and 4b, and each lens portion guides light emitted from the lamp 1 to the entire surface of a liquid crystal light valve to be described later. The partial luminance unevenness existing in the lamp 1 is averaged, and the light amount difference between the center of the screen and the peripheral portion is reduced. The light passing through the integrator lens 4 is guided to the first dichroic mirror 7 after passing through the polarization conversion device 5 and the condenser lens 6.

  The polarization conversion device 5 is configured by a polarization beam splitter array (hereinafter referred to as a PBS array). The PBS array includes a polarization separation film and a phase difference plate (1 / 2λ plate). Each polarization separation film of the PBS array passes, for example, P-polarized light out of the light from the integrator lens 4 and changes the optical path of S-polarized light by 90 °. The optically polarized S-polarized light is reflected by the adjacent polarization separation film and emitted as it is. On the other hand, the P-polarized light transmitted through the polarization separation film is converted into S-polarized light by the retardation plate provided on the front side (light emitting side) and emitted. That is, in this case, almost all light is converted to S-polarized light.

  The first dichroic mirror 7 transmits light in the red wavelength band and reflects light in the cyan (green + blue) wavelength band. The light in the red wavelength band that has passed through the first dichroic mirror 7 is reflected by the reflection mirror 8 to change the optical path. The red light reflected by the reflection mirror 8 is light-modulated by passing through a lens 9 and a transmissive liquid crystal light valve 31 for red light. On the other hand, the light in the cyan wavelength band reflected by the first dichroic mirror 7 is guided to the second dichroic mirror 10.

  The second dichroic mirror 10 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 10 is guided to the transmissive liquid crystal light valve 32 for green light through the lens 11 and is modulated by being transmitted therethrough. The light in the blue wavelength band that has passed through the second dichroic mirror 10 is guided to the blue-light transmissive liquid crystal light valve 33 through the total reflection mirror 12, total reflection mirror 13, and lens 14, and is transmitted therethrough. It is optically modulated.

  Each of the liquid crystal light valves 31, 32, 33 includes a panel portion 31b, in which liquid crystal is sealed between an incident-side polarizing plate 31a, 32a, 33a and a pair of glass substrates (with pixel electrodes and alignment films formed). 32b, 33b and output side polarizing plates 31c, 32c, 33c. The liquid crystal light valves 31, 32, and 33 are in a light-impermeable state when no signal is supplied.

  The modulated light (each color video light) modulated by passing through the liquid crystal light valves 31, 32, 33 is synthesized by the cross dichroic prism 15 to become color video light. The color image light is enlarged and projected by the projection lens 16, and is projected and displayed on a screen (not shown).

  FIG. 2A is a block diagram showing an image processing system, a lamp control system, and a cooling fan control system of the projection display apparatus. The video signal processing circuit 21 receives the video signal, performs frequency conversion (scan line number conversion), gamma correction processing in consideration of the applied voltage-light transmission characteristic of the liquid crystal panel, and the corrected video signal (video data). ) To the liquid crystal drive circuit 22. The liquid crystal drive circuit 22 drives the liquid crystal light valves (31, 32, 33) based on the video signal. The system control circuit 20 controls operations of the video processing circuit power source 23, the lamp power source 24, and the lamp cooling power source 25. The video processing circuit power supply 23 is a circuit for supplying / stopping power to the video processing circuit 21, the lamp power supply 24 is a circuit for supplying / stopping power to the lamp 1, and the lamp cooling power supply 25 is supplied to the lamp cooling fan 26. This is a circuit that performs power supply / stop and power amount adjustment. The temperature sensor 27 measures the temperature of the lamp 1 or the ambient temperature of the lamp 1 and gives this measurement information to the system control circuit 20.

  FIG. 3 is a flowchart showing the processing contents when the power of the liquid crystal projector is turned off by the system control circuit 20. For example, when the system control circuit 20 receives a signal indicating power OFF from a remote control signal light receiving unit (not shown), the system control circuit 20 stops the power supply by the video processing circuit power supply 23 and the power supply by the lamp power supply 24 (step S1). Then, a maximum power supply command is given to the lamp cooling power supply 25 (step S2). The system control circuit 20 determines whether cooling is completed based on the measurement information of the temperature sensor 27 (step S3). When it is determined that the cooling is completed, the power supply by the lamp cooling power supply 25 is stopped (step S4).

  With the above configuration, when the power OFF command is received, the lamp 1 is turned off and the image generation is stopped, so that no image is projected on the screen. When the power OFF command is received, the cooling fan 26 cools the lamp 1 with the maximum cooling capacity, so that the time until the cooling is completed is shortened. Therefore, the lamp can be turned on as soon as possible after the lamp is turned off, and user dissatisfaction can be reduced.

  When the liquid crystal projector includes a TV tuner and a tuner power supply, and the system control circuit 20 controls the power supply to the tuner power supply, the system control circuit 20 receives the power-off command when the video processing circuit power supply is received. It is preferable not only to stop power supply by the power supply 23 but also to stop power supply to the tuner power supply. In the above-described embodiment, the completion of cooling is determined by the temperature sensor 27. However, a timer that starts time measurement from the time when the power OFF command is received is provided. You may make it determine. In the above-described embodiment, a three-plate liquid crystal projector using a liquid crystal display panel is shown. However, the present invention can also be applied to a projection display apparatus having another image light generation system.

1 is a configuration diagram showing an optical system of a liquid crystal projector of an embodiment of the present invention. It is the block diagram which showed the liquid-crystal projector image processing system, the lamp control system, and the lamp fan control system. It is the flowchart which showed the processing content.

Explanation of symbols

1 Lamp 20 System Control Circuit 23 Video Processing Circuit Power Supply 24 Lamp Power Supply 25 Lamp Cooling Power Supply 26 Lamp Cooling Fan 27 Temperature Sensor 31, 32, 33 Liquid Crystal Light Valve

Claims (3)

In a projection display apparatus for projecting an image by modulating light emitted from a lamp with a light valve, the projector has a lamp cooling unit for cooling the lamp, and when a power OFF command is received, A projection display apparatus characterized in that the lamp cooling unit is driven with a high cooling capacity. 2. The projection display apparatus according to claim 1, further comprising a temperature sensor for measuring the temperature of the lamp or the vicinity of the lamp, and stopping the driving of the lamp cooling unit when the completion of cooling is determined by the output of the temperature sensor. A projection-type image display device characterized in that 2. The projection display apparatus according to claim 1, further comprising a timer that measures a lapse of a predetermined time from when a power-off command is received, and stops driving the lamp cooling unit when the predetermined time has elapsed. A projection display apparatus characterized by the above.

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