JP2003035932A - Lamp drive unit of projector and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome the problem that the lighting property of a lamp is deteriorated when the temperature of the lamp is high or low, and the problem that the performance of the lamp is lowered due to a load applied to a lamp electrode when the lighting characteristic of the lamp is deteriorated. SOLUTION: In the lamp drive unit of a projector 1 having the lamp 2, a control means 7 controls a lamp power supply means 3 to drive the lamp when the lamp 2 is turned on, on the basis of a result detected by a lamp temperature detecting means 6 to detect the temperature of the lamp 2. The control means 7 further controls the airflow of a cooling fan 4 on the basis of results detected by an ambient temperature detecting means 5 and the lamp temperature detecting means 6. Thereby, the lighting property of the lamp is improved, damage when lighting the lamp is reduced, and the reliability of the lamp is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp driving device for a projector and a driving method thereof, and more particularly to a lamp driving device and a driving method thereof in which the lighting property of the lamp is improved.

[0002]

2. Description of the Related Art Generally, as a lamp of a liquid crystal projector, for example, as shown in the characteristic diagram of FIG. 4, a 150 W lamp has a normal lamp voltage of 80 V and a lamp current of 1.5 A. At start-up, a high voltage pulse of about 20 KV is applied like the lamp voltage line A, and an overcurrent of about 20 A is applied like the lamp current line B, and the application time is a pulse waveform. And the unit is several nanoseconds (10 ns in FIG. 4).

Further, the lamp 2 of this liquid crystal projector
As shown in the cross-sectional view of the lamp in FIG. 5, the lamp has a lamp body 10 connected to the lamp electrode 11 and a reflector 12. The lamp temperature of the lamp body 10 is 1000 °.
C, 400 ° C for lamp electrode 11, 5 for reflector 12
Since the temperature is 00 ° C and the temperature is high, the heat protection device is required.

As a heat protection device for this liquid crystal projector, there is one disclosed in Japanese Patent Application Laid-Open No. 2001-021999 (conventional example 1), which has an inclination sensor of an equipment casing and a temperature sensor inside the equipment, and a detection result. Controls the fan to protect the equipment from heat.

FIG. 6 is a block diagram of the thermal protection device for the projector according to the conventional example 1, which is a schematic configuration of the thermal protection device for the liquid crystal projector 1. As shown in FIG. 6, the thermal protection device for the liquid crystal projector includes a tilt sensor 21 for detecting the tilt of the liquid crystal projector.
The tilt information is arranged on the lower surface of the liquid crystal projector housing and provides the control means (microcomputer) 23 with tilt information necessary for determining the installation state of the projector.

On the other hand, the heat protection device is provided with a temperature sensor 22, which is arranged at a predetermined position inside the liquid crystal projector casing, detects the temperature inside the equipment, and controls the temperature information. Give to 23. Further, the power supply unit section 24 controls the power supply to the fan control section 25, each circuit block 28 which is a main circuit group in the liquid crystal projector, the lamp 2 as a light source, and the like under the control of the control means 23.

The fan control section 25 is an intake fan 26 provided at a predetermined position in the liquid crystal projector housing.
Also, the rotation of the exhaust fan 27 is controlled, and the rotation amount of each fan can be adjusted by controlling the driving means such as a motor provided in each fan 26, 27. The intake fan 26 injects fresh air from the outside of the housing into the housing by its rotation, and the exhaust fan 27, on the contrary, exhausts the hot air inside the housing to the outside of the housing by its rotating action. In other words, the air blown by these fans 26, 27 can circulate the air from the outside inside the equipment casing, or can blow the air directly to the member that raises the temperature, thus cooling the inside of the casing. It becomes possible to do.

In this heat protection device, in order to perform the optimum heat protection processing according to the installation condition of the equipment, the control means 23 is
Various controls are performed based on the tilt information and the temperature information from the tilt sensor 21 and the temperature sensor 22. That is, the control means 2
Reference numeral 3 denotes, for example, a microcomputer that takes in the tilt information detected by the tilt sensor 21 and determines the installation state of the liquid crystal projector using the tilt information. In this case, when the tilt information is substantially horizontal, it is determined to be the stationary state, and when the inclination information has a certain angle, it is determined to be the suspended state.

Further, the control means 23 has a memory, and the memory is provided with a temperature set value table 23a in which optimum temperature set values are stored in accordance with the installation state of the equipment. , The temperature set value table 2
It is possible to drive and control the fan control unit 25 or the power supply unit unit 24 so that the optimum temperature set value is obtained by using 3a. In this case, the control means 23 always recognizes the temperature condition inside the device based on the temperature information from the temperature sensor 22, and when the temperature exceeds a predetermined value, for example, controls the fan control unit 25, By increasing the rotation speed of the intake fan 26 or the exhaust fan 27 or controlling the power supply unit 24, the power supply to each circuit block 28 and the lamp 2 is stopped.

Therefore, the control means 23 determines the installation state of the device using the inclination information from the inclination sensor 21, and further, based on the temperature information from the temperature sensor 22, the optimum thermal protection according to the installation state of the device. The processing can be done automatically.

Further, Japanese Unexamined Patent Publication No. 2000-131763 (conventional example 2) discloses that the detection result of an atmospheric temperature sensor
In addition to controlling the air volume of the cooling fan, the heater and the Peltier element attached to the lamp appropriately control the temperature of the lamp to speed up the cooling time of the lamp and the waiting time until relighting.

7 (a) and 7 (b) are a simplified overall perspective view and a sectional view of a lamp portion of the projector of the conventional example 2, and FIG. 8 is a block diagram thereof. This projector includes a lamp unit 30, cross dichroic prisms 33 and 36, and four reflection mirrors 3 on a base 38.
4, 4 liquid crystal panels 35, lens 37, fan 40,
A temperature sensor 42 and the like are mounted and configured.

The light generated by the lamp unit 30 enters the cross dichroic prism 33. The two joint surfaces of the cross dichroic prism 3 are R (red),
A dichroic coat that reflects only light in the B (blue) wavelength range is applied. The light in the R wavelength range of the light that has entered the cross dichroic prism 33 is reflected by one of the cemented surfaces, and then reflected by the reflection mirror 34,
The liquid crystal panel 25 forming the R and B optical images is illuminated. Further, the light in the G (green) wavelength range is transmitted without being reflected by the cross dichroic prism 33, and illuminates the liquid crystal panel 35 forming the G optical image.

Each liquid crystal panel 35 is a transmissive liquid crystal panel, in which the illumination light is converted into an optical image of each color and then given to the cross dichroic prism 36. The joint surface of the cross dichroic prism 6 is provided with a dichroic coat that reflects only the light in the R and B wavelength regions, and among the light that has entered the cross dichroic prism 36, the R and B light emitted from the liquid crystal panel 35 is Some of the image light is reflected on the cemented surface, and some of the G image light emitted from the liquid crystal panel 35 is not reflected on any surface.
In the cross dichroic prism 36, the image lights of three colors are combined and emitted. This light is projected on the screen by the projection lens 37.

In FIG. 7B, the lamp unit 30
Is a reflector 12 composed of a spheroidal reflection mirror.
Is fixed to the box 39, and the lamp 2 is the reflector 1
It is fixed to 2. The light emitted from the lamp 2 is reflected by the reflector 12 and enters the cross dichroic prism 33.

The temperature control means controls the fan 40, the atmospheric temperature detecting device 42, the signal transmission line 41, the heater 47 for adjusting the lamp temperature according to the signal transmitted from the signal transmission line 41, the Peltier element 46, and the temperature of the lamp. It comprises a lamp temperature detecting sensor 44 for detecting, an atmospheric temperature detecting device 42, and a controller 50 for controlling the fan 40, the heater 47, and the Peltier element 46 based on the detection data from the lamp temperature detecting sensor 44.

The heater 47, the Peltier element 46, and the lamp temperature detection sensor 44 are directly bonded to the lamp 2, and the bonding position is a position where the light emitted from the lamp 2 is not blocked. The atmospheric temperature detection device 42 is configured on the base 38 and detects the temperature of the atmosphere. Fan 40
It is configured on the base 38 near the lamp unit 30 and cools the atmosphere around the lamp unit 30.

FIG. 8 is a block diagram of a portion related to the temperature control means shown in FIG. The control unit 50 controls the power supply circuit 45 based on the operation of the power switch by the user. Further, the control unit 50 controls the Peltier element 46 and the heater 47, which are the second cooling means configured in the lamp unit 30, based on the detection result of the temperature of the lamp 2 sent from the lamp temperature detection sensor 44. Control. This data transmission and control is performed via the signal transmission line 41. Further, the control unit 50 controls the fan 40, which is the first cooling unit, based on the detection result of the atmospheric temperature sent from the atmospheric temperature detection device 42.

In the temperature control by the fan 40, the brightness of the lamp 2 varies depending on the temperature of the lamp at the time of light emission even if the applied voltage does not change. When the lamp 2 continues to emit light, it continues to emit heat, so that the temperature rises. In order to keep the temperature of the lamp 2 at the optimum temperature, the fan 40 is operated to cool the air around the lamp when the lamp 2 emits light, thereby lowering the rising lamp temperature. Here, the cooling level is determined based on the detection result of the atmospheric temperature by the atmospheric temperature detection device 42, and the fan 40 is drive-controlled according to the cooling level.

The temperature control by the Peltier element 46 and the heater 47 is performed by the user by turning on / off the main power source.
It is possible to instruct to turn off and to turn on / off the sub power supply. When the main power supply is turned on and the sub power supply is turned on, a voltage is applied to the lamp 2
When the temperature reaches the emission temperature, the image is projected (Lamp 2
Lights up). If the sub power supply is turned off when the lamp 2 is turned on, the temperature of the lamp 2 is lowered from the light emission temperature and turned off.

After a certain time has passed since the image was turned off, the lamp 2
When the temperature is cooled down to a predetermined relightable temperature or lower, the voltage can be applied to the lamp 2. Although the lamp 2 is manufactured to emit light at a predetermined light emission temperature, the lamp 2 is not lighted even if the light emission temperature is reached by applying a voltage when the temperature is higher than the relightable temperature.
If the auxiliary power supply is turned on when the temperature of the lamp 2 is higher than the relightable temperature, the lamp 2 cannot be relighted even if a voltage is applied, so the lamp 2 is cooled to the relightable temperature or lower. After waiting until the power is turned on, control to execute the instruction to turn on the sub power source is performed. In this case, the Peltier element 46 of the temperature control unit is used to perform control for shortening the fixed time required for the temperature of the lamp 2 to be cooled to the relighting temperature or less after the image is turned off.

[0022]

In the case of the above-mentioned conventional example 1, there is a problem that the temperature at the time of lighting the lamp is not taken into consideration, and in the case of the conventional example 2, there is a problem when the lamp is turned on. Considering that the driving method of the lamp is changed depending on the temperature, there is a problem that a device for controlling the temperature of the lamp becomes large.

That is, the first problem is that the lamp is difficult to light when the temperature of the lamp is high or low. The reason for this is that when the temperature of the lamp bulb is high, the pressure inside the bulb is also high. Therefore, it is difficult to generate high-voltage discharge between the electrodes by the pulse voltage for starting the lamp. Also,
This is because if the temperature of the electrode in the lamp bulb is low, the amount of electrons emitted from the electrode is reduced, and it becomes difficult to shift from high-voltage discharge to arc discharge.

The second problem is that if the lighting performance of the lamp deteriorates, the load on the lamp electrode is increased and the performance of the lamp deteriorates.

An object of the present invention is to provide a lamp driving device for a projector, which not only improves the lighting performance of the lamp in the projector but also alleviates the load at the time of lighting the lamp and improves the reliability of the lamp.

[0026]

SUMMARY OF THE INVENTION According to the structure of the present invention, in a lamp driving device having a lamp power source means for driving a lamp of a projector, a lamp cooling means for cooling the lamp and a lamp temperature for detecting the temperature of the lamp. Detecting means, atmospheric temperature detecting means for detecting the temperature of the atmosphere around the lamp, and control means for controlling the lamp power supply means by the temperature detected by the lamp temperature detecting means, the control means, The lamp cooling means is controlled by a temperature detected by the lamp temperature detecting means and a temperature detected by the atmospheric temperature detecting means.

In the present invention, the lamp cooling means is a cooling fan, the lamp temperature detecting means and the atmospheric temperature detecting means are thermistors, and the lamp temperature detecting means relays to the lamp itself or the vicinity thereof. In addition, the ambient temperature detecting means can be relayed to the exhaust portion of the cooling fan.

According to another structure of the present invention, in a lamp driving method having a lamp power supply means for driving a lamp of a projector, the temperature of the lamp is detected by a lamp temperature detecting means, and the lamp is cooled by a lamp cooling means. Then, the temperature of the atmosphere around the lamp is detected by the atmospheric temperature detecting means, and the control means controls the lamp power source means by the temperature detected by the lamp temperature detecting means, and detects the atmospheric temperature detecting means. The lamp cooling means is also controlled according to the temperature.

Further, in the present invention, the control of the lamp cooling means controls the temperature of the lamp cooling means by multiplying the temperature detected by the lamp temperature detecting means and the temperature detected by the atmospheric temperature detecting means by a correction coefficient. You can control.

According to the structure of the present invention, the control means controls the driving means of the lamp when the lamp is turned on, based on the result detected by the lamp temperature detecting means of the projector, and the atmospheric temperature detecting means and the lamp temperature detecting means. Based on the result detected by the means, the control means can control the air volume of the cooling fan to improve the lighting property of the lamp.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. Referring to FIG. 1, according to the present embodiment, a projector 1 includes a lamp 2, a lamp power source 3 that drives the lamp 2, a cooling fan 4 that cools the lamp 2, and an ambient temperature that detects the temperature of air to be cooled. The first thermistor 5 of the sensor, the thermistor 6 of the lamp temperature detecting sensor that detects the temperature of the lamp 2, and the cooling fan 4 are controlled by the temperature detected by the thermistor 5, and the lamp 2 is controlled by the temperature detected by the second thermistor 6. The control unit 7 controls the lamp power supply 3 to be driven.

The control of the lamp 2 will be described with reference to FIGS. First, referring to FIG. 2 (a), when the temperature of the lamp is as high as T22, the pressure in the lamp bulb is also high. Therefore, in order to cause the discharge between the lamp electrodes 11 by the pulse voltage of the lamp starting, A high pulse voltage V22 pressure is applied to the lamp 2 from the power supply. Further, when the temperature of the lamp is as low as T21, a high pulse voltage is not required, so a pulse voltage V21 lower than the pulse voltage V2 is applied to light the lamp.

Further, referring to FIG. 2 (b), when the temperature of the lamp is as low as T31, the temperature of the lamp electrode 11 in the lamp bulb also becomes low, so that the emission of electrons from the electrode is increased. The time during which an overcurrent is passed through the electrode when the lamp is lit is extended (t31), and the electrode is warmed to facilitate the transition from high-voltage discharge to arc discharge and the lamp is lit. Further, when the temperature of the lamp is as high as T32, the electrode of the lamp does not require the overcurrent for a long time, and therefore the time for flowing the overcurrent is shortened from t31 to t32 to light the lamp.

Control of the cooling fan will be described with reference to FIGS. Referring to FIG. 3A, when the temperature of the atmosphere is as high as T42, the cooling efficiency is reduced, so the flow rate of the cooling fan is controlled to be as large as V42. Further, when the temperature of the atmosphere is as low as T41, the cooling efficiency is high, so the flow rate of the cooling fan is controlled to V41.

Further, referring to FIG. 3B, when the temperature of the lamp is as high as T52, the flow rate of the cooling fan is changed to V52.
If the temperature of the lamp is as low as T51, the flow rate of the cooling fan is set to V51 to control the flow rate of the fan.

As another embodiment of the present invention, there is also a method in which the position of the thermistor for detecting the temperature of the lamp is attached to the vicinity of the lamp from the lamp itself, and the detected temperature is used as the temperature of the lamp to implement the present invention. As still another embodiment, there is a method in which a thermistor is attached to the exhaust portion of a fan for cooling the lamp and the temperature detected by the thermistor is used to carry out the present invention. As for the control of the fan, there is also a method of controlling the cooling flow rate of the fan after multiplying the respective detected temperatures of the atmospheric temperature and the lamp temperature by a correction coefficient.

[0037]

As described above, according to the constitution of the present invention,
It has the following effects. The first effect is that the lighting property of the lamp is improved even at a low temperature of the lamp.
The reason is that by increasing the time for which an overcurrent flows through the electrode of the lamp when the lamp is on, the electrode warms up faster and electrons are more easily emitted from the electrode, so the transition from high-voltage discharge to arc discharge is smooth when the lamp is on. This is because

The second effect is that the lighting performance of the lamp is improved even when the temperature of the lamp is high immediately after the lamp is turned off. The reason is that by increasing the pulse voltage in high-voltage discharge when the lamp is lit, even when the temperature of the lamp is high and the pressure inside the lamp bulb is high,
This is because the high-voltage discharge becomes smooth.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

2A and 2B are graphs showing a relationship between a lamp temperature, a pulse voltage, and an overcurrent in the embodiment of the present invention.

3A and 3B are graphs showing atmospheric temperature, lamp temperature, and fan flow rate according to the embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a first conventional example.

FIG. 5 is a graph showing the relationship between lamp temperature and fan flow rate according to the embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a first conventional example.

7 (a) and 7 (b) are a perspective view and a sectional view of a lamp portion thereof for explaining the configuration of a second conventional example.

FIG. 8 is a block diagram illustrating the configuration of the conventional example of FIG.

[Explanation of symbols]

1 projector 2 lamps 3 lamp power supply 4 cooling fan 5 First Thermistor 6 Second Thermistor 7 control unit 10 lamp body 11 Lamp electrode 12 reflector 21 Tilt sensor 22 Temperature sensor 23 Control means 23a Temperature set value table 24 Power supply unit 25 Fan control section 26 Intake fan 27 Exhaust fan 28 circuit blocks 29 Optical block 30 lamp units 31 signal line 33,36 Cross dichroic prism 34 Reflection mirror 35 LCD panel 38 bases 39 cases 40 fan (first cooling means) 42 Air temperature detector 44 Lamp temperature detection sensor 45 power supply 46 Peltier element (second cooling means) 47 heater 50 control unit

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Claims (7)

[Claims] 1. A lamp driving device having a lamp power supply means for driving a lamp of a projector, a lamp cooling means for cooling the lamp, a lamp temperature detecting means for detecting a temperature of the lamp, and an atmosphere around the lamp. Atmosphere temperature detecting means for detecting the temperature of, and control means for controlling the lamp power supply means by the temperature detected by the lamp temperature detecting means, the control means,
A lamp driving device for a projector, characterized in that the lamp cooling means is controlled by a temperature detected by the lamp temperature detecting means and a temperature detected by the atmospheric temperature detecting means. 2. The lamp driving device for a projector according to claim 1, wherein the lamp cooling means comprises a cooling fan. 3. The lamp driving device for a projector according to claim 1, wherein the lamp temperature detecting means and the atmospheric temperature detecting means are a thermistor. 4. The lamp driving device for a projector according to claim 1, wherein the lamp temperature detecting means is arranged in or near the lamp itself. 5. The lamp driving device for a projector according to claim 2, 3 or 4, wherein the atmospheric temperature detecting means is connected to an exhaust portion of the cooling fan. 6. A lamp driving method having a lamp power supply means for driving a lamp of a projector, wherein the temperature of the lamp is detected by a lamp temperature detecting means, the lamp is cooled by a lamp cooling means, and the atmosphere around the lamp is detected. The temperature of the lamp is detected by the ambient temperature detecting means, the control means controls the lamp power source means by the temperature detected by the lamp temperature detecting means, and the lamp cooling means is controlled by the temperature detected by the ambient temperature detecting means. A method of driving a lamp of a projector, which is characterized in that it also controls. 7. The control of the lamp cooling means controls the amount of cooling air of the lamp cooling means by multiplying the temperature detected by the lamp temperature detecting means and the temperature detected by the atmospheric temperature detecting means by a correction coefficient. 5. A method of driving a projector lamp according to item 5.