JPH05232267A - Power source apparatus for projection type display device - Google Patents

Abstract

PURPOSE:To eliminate adverse effect as caused by heat in the apparatus when a power source plug is pulled off a plug socket or a main power source switch is turned OFF by mistake by allowing the moving of a projector with the pulling of the power source plug off the plug socket immediately when a lamp for a light source is turned OFF. CONSTITUTION:In a projection type display device which is adapted to supply a voltage for driving to a lamp 26 for a light source which irradiates a liquid crystal light valve 28 with light for display and fan motors 18 and 20 for discharging heat by the lamp 26 for the light source from a main power source circuit 14, a charging circuit (spare power source circuit) 40 is provided in an electric line with which a drive voltage is supplied to at least one of the fan motors 18 and 20 for discharging heat from the main power source circuit 14. When the supply of the voltage to the fan motors 18 and 20 for discharging heat from the main power source circuit 14 is gone, the charging circuit (spare power source circuit) 40 supplies the drive voltage to the fan motors for discharging heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source lamp for irradiating a light valve with display light, and a heat exhaust fan motor for exhausting heat from the light source lamp. The present invention relates to an improvement in a power supply device of a projection display device which supplies a driving voltage from a circuit.

[0002]

2. Description of the Related Art Conventionally, this type of power supply device has been constructed as shown in FIG. That is, the main power circuit 14 is coupled to the power plug 10 via the main power switch 12, and the main power circuit 14 is connected to the signal processing circuit (mounted on the board) 16 and the fan motors 18 and 20 for heat exhaust. The lamp power switch 22 is supplied with the driving voltage.
After that, a driving voltage is supplied to the light source lamp 26 via the lamp power supply circuit 24. 28 is a liquid crystal light valve (L
CD). The main power supply circuit 14 includes a rectifier circuit 30, a smoothing capacitor 32, a three-terminal voltage stabilizer (eg, TA78L).
006AP).

Then, the signal processing circuit 16 sends a display signal to the liquid crystal light valve 28, and the light source lamp 26 illuminates the liquid crystal light valve 28 with display light to screen it.
The projected image is displayed on the LCD panel or the image is displayed directly on the liquid crystal light valve 28. During this display, the heat exhaust fan motors 18, 20 exhaust and cool the heat in the projection device heated by the light source lamp 26, but after watching, the lamp power switch 22 is turned off and the light source lamp 24.
Even after the light is turned off, the fan motors 18 and 20 for heat exhaust are driven for a predetermined time (for example, 3 minutes) to cool the inside of the apparatus to a predetermined temperature (for example, room temperature), and the optical system inside the apparatus, In particular, the liquid crystal light valve 28 is prevented from being adversely affected by heat.

[0004]

However, in the conventional example shown in FIG. 2, the lamp power switch 22 is turned off and the light source lamp 26 is extinguished for a predetermined time (for example, 3 seconds).
Since the fan motors 18 and 20 for heat exhaust must be continuously driven (for a period of time), there were the following problems.

(A) It is necessary to continue supplying voltage from the power plug 10 to the projection device for a predetermined time even after the light source lamp 26 is turned off and the viewing is finished, and the projection device must be kept in the same place. Therefore, there is a problem in that it is practically inconvenient to handle.

(B) If the power plug 10 is accidentally unplugged from the outlet or the main power switch is turned off immediately after the light source lamp 26 is turned off and the viewing is finished,
There is a problem that the heat exhaust is insufficient and the optical system in the device, particularly the liquid crystal light valve 28, is easily affected by heat.

The present invention has been made in view of the above problems, and the projector can be moved by unplugging the power plug from the outlet as soon as the light source lamp is turned off and the viewing is finished. Pull it out,
An object of the present invention is to provide a power supply device for a projection display device in which the optical system in the device is not adversely affected by heat even if the main power switch is turned off.

[0008]

SUMMARY OF THE INVENTION A power supply device for a projection display device according to the present invention comprises a light source lamp for irradiating a light valve with display light, and a heat exhaust for cooling the light source lamp. In a projection display device in which a driving voltage is supplied from a main power supply circuit to a fan motor, the heat exhaust fan is used when no voltage is supplied from the main power supply circuit to the heat exhaust fan motor. It is characterized in that a standby power supply circuit for supplying a drive voltage to the fan motor is provided.

[0009]

When a driving voltage is supplied from the main power supply circuit to the light source lamp and the heat exhaust fan motor, the light source lamp irradiates the light valve with display light, and the heat exhaust fan motor drives the device. The heat inside is exhausted and cooled. If you accidentally unplug the power plug from the outlet or turn off the main power switch while watching, or if you unplug the power plug from the outlet or turn off the main power switch immediately after turning off the light source lamp after watching. In this case, the voltage supply from the main power supply circuit to the heat exhaust fan motor disappears, but the standby power supply circuit continues to drive the heat exhaust fan motor by supplying the drive voltage to the heat exhaust fan motor, Exhaust heat to cool.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power supply device for a projection type display device according to the present invention will be described below with reference to FIG. In FIG.
The same parts as those in FIG. 2 are designated by the same reference numerals. In FIG. 1, reference numeral 10 is a power plug for supplying and shutting off a main power supply voltage by inserting / removing into / from an outlet, and a main power supply circuit 14 is coupled to the power plug 10 via a main power switch 12.

The main power supply circuit 14 comprises a rectifying circuit 30, a smoothing capacitor 32, and a three-terminal voltage stabilizer 34, and has a known structure. The main power supply circuit 14 supplies a driving voltage to the signal processing circuit 16 and the heat exhaust fan motor 18, and also passes through a lamp power switch 22.
The signal processing circuit 1 is configured to supply a driving voltage to the light source lamp 26 via the lamp power supply circuit 24.
Reference numeral 6 is configured to send a display signal to a liquid crystal light valve 28 as a light valve. The main power supply circuit 14 is further configured to supply a drive voltage to the heat exhaust fan motor 20 via a charging circuit 40 as a standby power supply circuit peculiar to the present invention.

The charging circuit 40 comprises a capacitor 42, diodes 44 and 46, a charging current limiting resistor 48 and a secondary battery (for example, a NiCd battery) 50. The main power supply circuit 14 is used for the heat exhaust fan module. The secondary battery 50 is charged by the main power supply circuit 14 when the drive voltage is supplied to the motor 20, and when the main power supply circuit 14 stops supplying the drive voltage to the heat exhaust fan motor 20. A drive voltage is supplied from the secondary battery 50 to the heat exhaust fan motor 20.

Next, the operation of the above embodiment will be described. (B) When the main power supply circuit 14 is connected to the outlet and the main power supply switch 12 is turned on to supply the main power supply voltage to the main power supply circuit 14, the main power supply circuit 14 causes the signal processing circuit 16 to operate.
And a driving voltage is supplied to the heat exhaust fan motor 18, a driving voltage is supplied to the heat exhaust fan motor 20 via the charging circuit 40, and the lamp power switch 22 is further supplied to the lamp power supply. A driving voltage is supplied to the light source lamp 26 via the circuit 24.

(B) Therefore, the signal processing circuit 16 sends a display signal to the liquid crystal light valve 28, and the light source lamp 26 irradiates the liquid crystal light valve 28 with display light to display it on the screen. The projected image is displayed, or the image is displayed directly on the liquid crystal light valve 28. During this display, the heat exhaust fan motors 18 and 20 exhaust the heat in the projection device heated by the light source lamp 26. At this time, the main power supply circuit 14 simultaneously operates the diode 4 of the charging circuit 40.
4, the charging current is supplied to the secondary battery 50 via the resistor 48 to charge the secondary battery 50.

(C) If the power plug 10 is accidentally unplugged from the outlet or the main power switch 12 is turned off during watching, or the lamp power switch 22 after watching has ended.
Immediately after turning off the power source lamp 26 and turning off the light source lamp 26, the power supply plug 10 is unplugged from the outlet or the main power supply switch 12 is turned off to supply the voltage from the main power supply circuit 14 to the heat exhaust fan motor 20. Then, the secondary battery 50 in the charging circuit 40 supplies the driving voltage to the heat exhaust fan motor 20 through the diode 46. Therefore, the heat exhaust fan motor 20 continues to be driven to exhaust the heat in the apparatus to cool it.

In the above embodiment, the charging circuit is provided in the line for supplying the driving voltage from the main power supply circuit to one of the two heat exhaust fan motors, and the one heat exhaust fan motor is provided.
Although the drive voltage is supplied from the secondary battery in the charging circuit when the drive voltage is no longer supplied from the main power supply circuit to the battery, the present invention is not limited to this, and the main power supply circuit is used. A charging circuit may be provided in the line that supplies the driving voltage to the two heat exhaust fan motors.

In the above embodiment, the standby power supply circuit is composed of the charging circuit. However, the present invention is not limited to this, and there is no drive voltage supply from the main power supply circuit to the heat exhaust fan motor. It is sufficient that the driving voltage is supplied to the heat exhaust fan motor at this time. For example, the auxiliary power supply circuit may be configured by combining a changeover switch and a storage battery, or the auxiliary power supply circuit may be configured by only a capacitor having a predetermined capacity.

[0018]

As described above, the power supply device according to the present invention is provided with a light source lamp and a heat exhaust fan motor from the main power supply circuit.
In a projection display device in which a drive voltage is supplied to the motor and the drive voltage is supplied from the main power supply circuit to the heat exhaust fan motor, the drive voltage is supplied to the heat exhaust fan motor. A standby power supply circuit is provided, so if you accidentally disconnect the power plug from the outlet or turn off the main power switch while operating the projection device and viewing the projected image,
Or even if the power plug is unplugged from the outlet or the main power switch is turned off immediately after turning off the light source lamp after watching, the standby power supply circuit supplies the drive voltage to the heat exhaust fan motor for heat exhaust. The fan fan motor can be continuously driven, and cooling air can be sent into the device to exhaust heat from the device to cool the device.

Therefore, when the lamp for the light source is turned off and the viewing of the projected image is finished, the power plug can be immediately unplugged from the outlet to move the projection device. Even if it is turned off, it is possible to prevent the optical system in the apparatus from being adversely affected by heat.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a power supply device for a projection display device according to the present invention.

FIG. 2 is a schematic configuration diagram of a conventional device.

[Explanation of symbols]

10 ... Power plug, 12 ... Main power switch, 14 ...
Main power supply circuit, 18, 20 ... Fan motor for heat exhaust, 2
2 ... Lamp power switch, 24 ... Lamp power circuit, 2
6 ... Light source lamp, 28 ... Liquid crystal light valve (example of light valve), 40 ... Charging circuit (example of standby power supply circuit), 44, 46 ... Diode, 48 ... Resistor, 50
… Secondary battery.

Claims (2)

[Claims] 1. A light source lamp for irradiating a light valve with display light and a heat exhaust fan motor for exhausting heat from the light source lamp, and a driving voltage from a main power supply circuit. In the projection display device, the standby power supply circuit is provided to supply a drive voltage to the heat exhaust fan motor when the main power supply circuit stops supplying voltage to the heat exhaust fan motor. A power supply device for a projection display device characterized by the following. 2. A standby power supply circuit charges a secondary battery by the main power supply circuit while supplying voltage from the main power supply circuit to a heat exhaust fan motor, and the main power supply circuit discharges heat from the secondary battery. 2. The power supply device for a projection display device according to claim 1, wherein the power supply device for the projection display device is mainly composed of a charging circuit that supplies a voltage from the secondary battery to the heat exhaust fan motor when the voltage is no longer supplied to the fan motor.