JPH02311886A - Video projector - Google Patents

Abstract

PURPOSE:To prevent the life of a lamp from being shortened and to effectively suppress unnecessary power consumption by stopping power supply to a lamp light source from a lamp driving power source when a discrimination means judges that a video signal is not inputted for a specified time or more. CONSTITUTION:The video signal discrimination means 50 discriminates whether or not the video signal is inputted from the outside. As a result, when it is judged that the video signal is not inputted, a control means 52 stops the supply of driving power to the lamp light source 22, which is turned off. When it is judged that the video signal is inputted again after stopping the power supply, the driving power is supplied to the lamp light source, which is turned on. Thus, the life of the lamp is prevented from being shortened and the unnecessary power consumption is effectively suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a video projector, and particularly to lighting drive control of a lamp light source thereof.

[Prior Art] As a video projector, there is one shown in FIG. 2, for example. The one shown in the figure uses a liquid crystal light valve.

In the figure, driving power supplied from a main power supply/switch 10 to a circuit power supply circuit 12 is adjusted for driving the circuit and supplied to a signal processing circuit 14. A video signal is input from the outside to this signal processing circuit 14, and predetermined signal processing is performed here. As a result of this processing, R(
red).

G (green) and B (blue) video drive signals are generated and supplied to the liquid crystal light valves 16, 18, and 20, respectively.

On the other hand, the light emitted from a light source such as a halogen lamp or the lamp 22 has its infrared rays cut off by an appropriate filter so that heat is not transmitted to the entire surface, and then enters the blue gyroic mirror 24. Then, separation of the blue light is performed here, and the blue light is further reflected by the mirror 26 and enters the liquid crystal light valve 20.

Next, the light transmitted through the blue dichroic tube Cumira-24 is
The green light is incident on the green light chromic mirror 28, where the green light is separated. The green light enters the liquid crystal light valve 18. Further, the red light transmitted through the green guichroic mirror 28 is reflected by the reflection mirrors 30 and 32, and
The light enters the liquid crystal light valve 16.

In this way, the R, G, and B lights enter the liquid crystal light valve 16°18.20, and the R, G, and B lights also enter the liquid crystal light valve 16°18.
Each video drive signal is incident, and each liquid crystal light valve 16, 18, 20 is driven by this signal. And each liquid crystal light valve 16, 18.2
RlG and B light passes through 0, respectively, and R, G, and B images are generated, respectively. These images are combined by a color combining guichroic prism 34, and a combined color image is projected onto a screen 38 by a projection lens 36.

With the above operation, the circuit power supply circuit 12. Signal processing circuit 14
Power is supplied to the lamps 22 and 22 in accordance with the rON and rOFFI operations by the main power switch 10. Note that the fan 40.42 causes the lamp 22 to
Cooling is being carried out in the necessary parts such as lamp 22.
9. Cooling is continued for some time after the roFFJ.

Therefore, the power supply to the fan 40 is stopped after a predetermined period of time has elapsed since roFFJ of the main power switch 10.

[Problems to be Solved by the Invention] However, the conventional device as described above has the following disadvantages. First of all, if the user forgets to turn on the power roFFJ for some reason such as going out while using the projector, or if the user falls asleep, the projector will be left turned on for a long time even after the image has been projected. It will be done.

Then, the lamp 22 continues to be lit.
Its lifespan will be unnecessarily reduced. Particularly, when an expensive halogen lamp or the like is used as the lamp 22 to achieve high brightness, replacing the lamp becomes uneconomical and requires a lot of effort.

Further, when the power is in the "ON" state, power is being supplied to each circuit and light source as described above, resulting in unnecessary power consumption.

The present invention has been made in view of this point.

It is an object of the present invention to provide a video projector that can prevent a reduction in lamp life and effectively suppress unnecessary power consumption.

[Means for Solving the Problems] The present invention provides a video projector in which a lamp light source for obtaining projection light of an image based on a video signal is driven to turn on by power supply from a lamp drive power source. and when it is determined by this determining means that there is no video signal input for a predetermined period of time or more.

The apparatus is characterized by comprising a control means for stopping power supply to the lamp light source by the lamp driving power source.

[Operation] According to the present invention, the determination means determines whether or not a video signal is input from the outside. As a result, when it is determined that no video signal is being input, the control means stops supplying driving power to the lamp light source, and the lamp light source is turned off. In addition, if it is determined that the video signal is input again after the supply is stopped, 1. Driving power is supplied to the lamp light source, and the lamp light source is turned on.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings. Note that the same reference numerals are used for the same components as in the conventional example described above.

FIG. 1 shows the main parts of a liquid crystal video projector according to an embodiment of the present invention. In the figure, the video signal input side of the signal processing circuit 14 is connected to the input side of a video signal discrimination circuit 50. The output side of this video signal discrimination circuit 50 is connected to the input side of a system controller 52. The system controller 52 is supplied with necessary operating power from the circuit power supply circuit 12.

Next, the input side of the circuit power supply circuit 12 described above is connected via the main switch 56 to the output side of the outlet 54 which is connected to a commercial power source AC (not shown). Further, the input side of the lamp drive power source 6o is connected to the main switch 56 via a lamp control switch 58. The output side of this lamp drive power source 60 is connected to the lamp 22 described above.

Among the above-mentioned units, the video signal discrimination circuit 50 is a known circuit for determining whether or not a video signal is input to the projector from the outside.The system controller 52 is composed of a CPU and the like. When the video signal discrimination circuit 50 determines that there is no video input, the operation of each part is controlled, such as setting the lamp control switch 58 to the rOFFJ state. Further, the lamp drive power source 60 is connected to the lamp control switch 58 (7).
) rONJ, rOFFJ 1. :, based on lamp 2
This is to supply a lighting electrode to the 2.

Next, the operation of the above embodiment will be explained. ,
First, the main switch 56 is turned on by the operator.
It is assumed that the video signal has not been inputted even though the status has become "N". When the main switch 56 is turned on, the circuit power supply circuit 12 supplies operating power to each circuit. In this case, the video signal determination circuit 50 determines that there is no video signal input, and this fact is transmitted to the system controller 52. The system controller 52 sets the lamp control switch 58 to the rOFFJ state based on the determination result. For this reason,
No power is supplied to the lamp 22 by the lamp drive power supply 60.

Next, when the operator inputs a video signal, the video signal determination circuit 50 determines that fact, and this is transmitted to the system controller 52. In this case, the lamp control switch 58 is turned "ON" by the system controller 52.

Then, power from the AC power source is input to the lamp driving power source 60, thereby supplying driving power to the lamp 22 and lighting it.

On the other hand, the input video signal is also input to the signal processing circuit 14, where it undergoes predetermined processing and is converted into R (red) and G.
(green) and B (blue) video drive signals are generated and supplied to the liquid crystal light valves 16, 18 and 20, respectively. These liquid crystal light valves 16, 18, 20 have lamps 2
With the lighting of No. 2, the R, G, and B portions are incident. As a result, R, G, and B images are generated as described above, and these images are combined by the color compositing gicroic prism 34 to project one composite color image onto the screen 38. .

Next, it is assumed that during the projection state as described above, the main switch 56 remains "ON" for some reason even though there is no video signal input (the video has ended). In this case, The video signal determination circuit 50 determines that there is no video signal input, and the system controller 52 transmits this to the lamp control switch 58.
is switched to rOFFJ. Then, the lamp drive power supply 60 stops supplying power to the lamp 22, and
Lamp 22 is turned off.

Note that the operation of the cooling fan is similar to that of the conventional device described above, and the fan also becomes roFFJ after a predetermined period of time has elapsed after rOF and FJ of the lamp 22.

In this way, according to the present embodiment, even if the main switch 56 is in the "ON" state, the lamp 22 will not be lit unless a video signal is input, so unnecessary lighting is reduced and the lamp's lifespan is extended. In addition, unnecessary power consumption can be reduced.

Note that the present invention is not limited to the above-mentioned embodiments. For example, instead of turning the lamp control switch 58 OFF immediately after determining that no video signal is input, the lamp control switch 58 is turned OFF after a few seconds.
oFFJ. This is to prevent unnecessary reactions to short-term unattended conditions such as switching the video input plug. Further, depending on the type of lamp 22, repeating "rON" and "rOFF" for a short time may actually shorten the lifespan, so this is to prevent this.

Furthermore, although the above embodiments apply the present invention to a liquid crystal video projector, this does not preclude application to other projectors.

[Effects of the Invention] As explained above, according to the present invention, it is possible to prevent a decrease in the lamp life and also to effectively suppress unnecessary power consumption.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing one embodiment of the present invention, and FIG.
The figure is a block diagram schematically showing a conventional video projector. lO...Main power supply/switch, 12...-Circuit power supply circuit, 14...-Signal processing circuit, 16.18.20...
Liquid crystal light valve, 22... Lamp, 28... Screen, 50... Video signal discrimination circuit, 52... System controller, 56... Main switch, 58
- Lamp control switch, 60... Lamp drive power supply. Patent applicant Kunio Kakiki, representative of Victor Japan Co., Ltd. Procedural amendment (method) 1989/θ month-Z day 1, case description 1999 patent application No. 135148 2, title of invention Video projector 3, Relationship with the case of the person making the amendment Patent applicant address: 3-12-5 Moriya-cho, Kanayō-ku, Yokohama-shi, Kanagawa Prefecture All drawings of the drawings subject to amendment

Claims (1)

[Scope of Claims] In a video projector in which a lamp light source for obtaining projection light of an image based on a video signal is turned on by power supply from a lamp driving power source, a determining means for determining whether or not the video signal is input. and a control means for stopping power supply to the lamp light source by the lamp drive power source when the determination means determines that there is no video signal input for a predetermined period of time or more.