JPH11102792A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device, capable of predicting service life of a discharge lamp used for a liquid crystal projection apparatus and avoiding explosion of the discharge lamp and destruction of a circuit. SOLUTION: This lighting device has an inverter part 2 for converting a DC power to an AC power and applying it to a lamp 3, an inverter control part 12 for adjusting the power supplied to the lamp, in response to a control input and a lamp power transition detecting part 11 for detecting a tempord transition of the lamp power, an when the power value of the lamp exceeds a given value, predicts the service time of the lamp according to a given control value of the inverter control part 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device, and more particularly to a discharge lamp lighting device capable of predicting the life of a discharge lamp used in a liquid crystal projection device.

[0002]

2. Description of the Related Art A high-intensity discharge lamp such as a metal halide lamp is used in a liquid crystal projection device.
Such a discharge lamp is lit by a discharge lamp lighting device. Generally, a high-intensity discharge lamp (hereinafter referred to as a lamp)
Due to variations in characteristics and changes in characteristics at the end of lamp life, the lamp voltage, which is the voltage between both terminals of the lamp after lighting, changes, and the luminous flux changes. In addition, the lamp has a characteristic that the gas pressure in the lamp is low and the luminous efficiency is low especially at the time of starting lighting. For this reason, if sufficient power is supplied during steady lighting at the start of lighting, the light does not immediately become bright. Therefore, in this type of conventional discharge lamp lighting device, when the lamp voltage is low immediately after starting the lighting,
A method is adopted in which a large current of a constant value is applied to the lamp, whereby the lamp voltage is rapidly increased, and the luminous flux is rapidly increased. After the lamp voltage reaches a predetermined value, the lamp is operated by supplying a constant power to the lamp by a circuit for keeping the lamp power supplied to the lamp constant.

For example, Japanese Patent Application Laid-Open No. 8-8087 discloses that
By setting the target lamp current or target lamp power not only with respect to the lamp voltage but also by taking into account the lighting time that is the elapsed time from the start of lighting,
It discloses that a smooth rise in the luminous flux is realized.

[0004] In general, despite the relatively short life of the lamps described above, a liquid crystal projection device using the lamps has the same characteristics as a long-life television monitor.
In particular, the lamp is used without taking into account the operating time of the lamp. Therefore, the brightness of the screen may be insufficient or lighting may not be possible. Further, when the lighting operation is forcibly performed after the life of the lamp has elapsed, or during the lighting after the life of the lamp has elapsed, the lamp itself may explode and the control circuit may be destroyed.

Japanese Patent Application Laid-Open No. 4-342990 discloses a countermeasure against a relighting operation or the like for surely turning on the light even when the light is abnormal. However, the above 2
In the two prior arts, the circuit and the lamp itself may be adversely affected, and no means for avoiding this is disclosed.

[0006]

For example, when the lighting time of the same lamp is accumulated and measured, and a warning is given to the user by a display means such as an LED when the life time exceeds a preset life time, No consideration is given to variations in the life and characteristics of individual lamps. Therefore, according to the standard, although the life time has not been reached,
Actually, there is a possibility that the lamp will be used beyond the service life, and the lamp may not be turned on or the lamp may explode. This has been a problem to be solved.

[0007]

In order to solve the above-mentioned problems, a discharge lamp lighting apparatus according to the present invention comprises: an inverter section for converting DC power supplied from a DC power supply into AC power and applying the AC power to a lamp; An inverter control unit that adjusts the lamp power supplied to the lamp according to the input; and a lamp power transition detection unit that detects a temporal change in the lamp power, wherein the lamp power value is a predetermined value. When the time exceeds the threshold, the life of the lamp is predicted and a warning on use is issued.

According to the present invention, it is possible to estimate the life not only by simply considering the life time of the lighting that is guaranteed by the standards set by the manufacturer, but also by taking into account variations in the characteristics of various lamps and temporal changes in the lighting characteristics. It is possible to provide a discharge lamp lighting device that can warn a user by displaying a result of life expectancy prediction on a display unit and prevent sudden explosion of a lamp and destruction of a control circuit.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The discharge lamp lighting device according to the first invention is
An inverter unit for converting DC power supplied from a DC power supply to AC power and applying the AC power to a discharge lamp (hereinafter, referred to as a lamp); an inverter control unit for adjusting lamp power supplied to the lamp according to a control input; A power transition detection unit that detects a temporal change in the lamp power, and when the value of the lamp power exceeds a predetermined value, the life of the lamp according to a predetermined control value of the inverter control unit. It is characterized by predicting time. As a result, it is possible to predict the life in consideration of not only the lighting life time guaranteed by the standard of the lamp manufacturer but also variations in characteristics of various lamps, changes in lighting characteristics, and the like.

According to a second aspect of the present invention, there is provided a discharge lamp lighting device for converting a DC power supplied from a DC power supply into an AC power and applying the AC power to the lamp, and detecting a current and a voltage applied from the inverter to the lamp. A current / voltage detection unit,
When the power obtained from the current value and the voltage value detected by the current / voltage detection unit exceeds a specified power value of the lamp by a predetermined ratio, the standard voltage of the lamp is set to V1, and a predetermined guaranteed life time T is set. The voltage after elapse is V
2. When the detection voltage of the current / voltage detection unit is V,
A controller that calculates the total lighting time X by calculating the following equation (V2−V1) / T = (V−V1) / X, and calculates the remaining life time of the difference between the total lighting time X and the guaranteed life time T. And By calculating the remaining life time by the above calculation, it is possible to obtain the remaining life time in consideration of the variation due to the variation of each lamp characteristic in addition to the life time predetermined by the standard, and it is possible to more accurately predict the life. . A discharge lamp lighting device according to a third aspect of the present invention is the discharge lamp lighting device according to the first aspect, wherein the voltage and the current applied from the inverter unit to the lamp each have a predetermined value, and are times required until the lamp reaches a predetermined energized state. A lamp lighting time measuring unit for measuring the lighting time, and a lamp for measuring a lighting success rate represented by a ratio between the number of times the lamp is started to be turned on and the number of times the lamp has reached a predetermined energized state and succeeded in lighting the lamp. A lighting success rate measurement unit, and a power transition characteristic detection storage unit that detects that the lamp power in the lighting state has exceeded a predetermined value, wherein at least one of the lighting time and the power value is a predetermined value. When the value exceeds the value or when the lighting success rate falls below a predetermined value, a lamp life warning indicating that the life of the lamp has expired is issued. By issuing a lamp life warning, it is possible to provide a discharge lamp lighting device that alerts a user not to use the lamp any more and prevents sudden explosion of the lamp and destruction of the control circuit.

<< Embodiment >> An embodiment of a discharge lamp lighting device according to the present invention will be described below with reference to FIGS. In FIG. 1, both terminals of a DC power supply 1 such as a battery are connected to respective input terminals of an inverter unit 2 for converting an input DC voltage into an AC voltage. An output terminal of the inverter unit 2 is connected to a switch unit 4 for supplying an inverter output to the lamp 3.
Is connected to the lamp 3 via the. A lighting circuit 5 for applying a high voltage to the lamp and forcibly lighting the lamp 3 is connected to the lamp 3. "Forcibly"
The operation having the phrase “operation” indicates an operation performed by controlling the discharge lamp lighting device. The lighting circuit 5 includes a high voltage generation circuit 22.
Through the controller 6. The other two output terminals of the inverter unit 2 are connected to the input terminals of the current / voltage detection unit 7 and the temperature detection unit 8, respectively. The output terminal of the current / voltage detection unit 7 is connected to the input terminals of the total number of lighting / time counting unit 10, the power transition characteristic detection / storage unit 11, the inverter control unit 12, and the lighting success rate measurement unit 13 in the controller 6. ing. The output terminals of the total lighting frequency / time counting unit 10, the power transition characteristic detection / storage unit 11, the inverter control unit 12, and the lighting success rate measuring unit 13 are connected in common, and the input terminals of the lighting time measuring unit 18 and the storage unit 16 are connected. It is connected to the. The output terminal of the temperature detecting section 8 is connected to the controller 6. The input terminal of the power adjustment unit 9 is connected to the inverter control unit 12, and the output terminal is connected to the switch unit 4. The output terminal of the inverter control unit 12 is connected to the inverter unit 2. The output terminal of the storage unit 16 is connected to the input terminal of the lamp status output unit 14, and the output terminal of the lamp status output unit 14 is connected to the display unit 15. A lamp on / off switch 17 for turning on or off the lamp 3 is connected to the controller 6.

The operation of the discharge lamp lighting device configured as described above will be described below. Lamp ON / OFF switch 17
When the controller 6 detects the lighting signal from the controller 3, the high voltage of the high voltage generating circuit 22 is forcibly applied from the lighting circuit 5 to the lamp 3 under the control of the controller 6, and the lamp 3 starts lighting. When the lighting of the lamp 3 is started, the switch unit 4 is turned off, and after the lamp lighting is completed, the switch unit 4 is turned on. The inverter unit 2 converts the DC power supplied from the DC power supply 1 into AC power, and based on a signal from the inverter control unit 12 in the controller 6, the inverter unit 2,
The optimum power is supplied to the lamp 3 via the power adjustment unit 9 and the switch unit 4 to maintain the optimum lighting state. The controller 6 sets the power to be supplied to the lamp 3 based on the detection signal of the current / voltage detection unit 7 for detecting the current and the voltage of the inverter unit 2 in order to maintain the optimum lighting state of the lamp 3, Is output from the inverter control unit 12 to the power adjustment unit 9. This control voltage is also applied to the inverter unit 2, and by changing the control voltage, the input voltage of the inverter unit 2 changes. The voltage and current applied from the inverter unit 2 to the lamp 3 also change according to the change in the input voltage, and the lamp power is controlled.

The temperature detector 8 detects the temperature of the lamp 3 and
When the temperature of the lamp 3 exceeds a predetermined value, the operation of the controller 6 is stopped and the lamp is turned off.

Hereinafter, the operation of the discharge lamp lighting device will be described in detail with reference to flowcharts. FIG. 2 is a flowchart showing a lamp power control procedure. In FIG. 1 and FIG. 2, in the normal power control, at step 41, an abnormality of the inverter unit 2 and the lighting circuit 5 is checked. If there is any abnormality, go to the power supply circuit abnormality routine in step 48, turn off the lamp,
A predetermined appropriate process such as a warning display on the display unit 15 is performed.
If there is no abnormality, the processing at steps 42 to 45 at the time of starting the lamp is performed. The relationship between the voltage and the current when the lamp 3 is forcibly turned on is set as follows. If the inverter voltage detected by the current / voltage detection section 7 of the inverter section 2 is 150 V or less and continues for 30 seconds or more (steps 42 and 43), the routine proceeds to the power supply circuit abnormality routine 48 to turn off the lamp. The detected inverter voltage is 150V
If the current of the inverter unit 2 is higher than 1 A and continues for 3 seconds or more (steps 44 and 46), it is determined that the lighting start of the lamp has failed, and the routine proceeds to the lamp non-lighting routine of step 47 and the lamp is turned on. The lamp is turned off, and a display indicating that the lamp start has failed is displayed on the display unit 15.

When the inverter voltage is higher than 150 V and the inverter current is higher than 1 A, it is determined that the lighting of the lamp has been successfully started. In step 45, power control at the time of starting the lighting of the lamp is performed. If the duration of the state where the inverter output voltage is 150 V or less is shorter than 30 seconds after starting the lamp lighting (steps 42 and 43), or if the lamp lighting is successful, the inverter voltage is higher than 150 V and the inverter current is more than 1 A ( At the time of steps 42 and 44), it is determined that the lamp is on. In step 49, the lighting time measuring unit 18 measures the lighting time required for lighting from the start of lamp lighting to the completion of lighting, and the storage unit 1
6 is stored.

In step 50, a lamp lighting success rate, which is a ratio of the number of times of lamp lighting start operation to the number of times of successful lamp lighting, is calculated, and the result is stored in the storage unit 16. The result of measuring the lamp power in the lighting state in steps 51 and 52 indicates that the rated value of the lamp (for example, 150 W) is 1
If it exceeds 0%, it is determined that the lamp usage time has exceeded the lamp life, and appropriate processing such as displaying a warning on the display unit 15 in a lamp life over routine (step 52) is performed. The variation within ± 3% of the rated value of the lamp power is regarded as an error range, the power value is determined to be normal, and the power control is continued (steps 53 and 55). If the lamp power is more than 3% increase (150 × 1.03) of 150 W, the inverter 2 is controlled to reduce the power in step 54. Next, the routine proceeds to a life estimation routine of step 57. Lamp power reduced by 3% of 150W (150x
0.97) or less, the process proceeds to a routine for controlling the inverter unit 2 to increase the power in step 56. As described above, the power control at the time of starting the lighting of the lamp and at the time of lighting is performed.

The total number of lighting times and time measuring unit 10 in the controller 6 always measures the total number of lighting times and the total lighting time of the same lamp, and the lighting time measuring unit 18 measures the time required from the start of lighting to the completion of lighting. measure. Then, based on the signal input from the current / voltage detection unit 7, the power transition characteristic detection / storage unit 11 calculates the following formula:

Lamp power = (inverter voltage−inverter current × A) × inverter current

The power is calculated in accordance with the equation (1), and the time variation of the power is detected and stored. Here, A represents the internal resistance of the lamp.

The lighting success rate measuring unit 13 calculates the lighting success rate of the ratio of the number of lighting successes to the number of lighting operations.

FIG. 3 is a graph showing the relationship between time and voltage at the start of lamp lighting when a 150 W lamp is used in this embodiment. The characteristic curve (a) shows a typical voltage-time characteristic when the total lighting time of the lamp exceeds the guaranteed life time. The characteristic curve (b) shows the voltage-time characteristic of a standard lamp whose total lighting time is within the guaranteed life time. The characteristic curve (c) shows a voltage-time characteristic when an impurity is attached to the lamp electrode. In the case of the characteristic curves (a) and (c) in the same figure, despite the optimum power control by the power adjustment unit 9, the lamp operates in a range beyond the optimum control range due to a change in the lamp characteristics, an excess of the use time, or the like. Therefore, it is known that such characteristics are obtained. Generally, when the lamp is controlled to have a constant power, the lamp voltage tends to increase in proportion to the use time. In FIG. 3, after d time (for example, 90 seconds) has elapsed after the start of lighting, the lamp voltage is increased by 10% from a predetermined control standard voltage (60 V in the control method of this embodiment using a 150 W lamp). (66 V for a 150 W lamp) for more than a fixed time (for example, 90 seconds), the lamp is forcibly turned off, and the lamp is displayed on the display unit 15 as a lamp error. I do. Before reaching the lamp state as described above, the lamp has a voltage-time characteristic intermediate between the characteristic curves (a) and (b). Therefore, in the present invention, in the same lamp, the characteristic curve (b)
Is out of a predetermined error range (for example, 3%) of the characteristic of the lamp, the increase of the current lamp voltage value with respect to the control standard voltage value, the guaranteed lifetime of the lamp, and the lamp voltage after the lifetime of the lamp has elapsed. The remaining time until the end of the guaranteed life time is calculated and predicted based on the increase of the control standard voltage (that is, the voltage of the characteristic curve (a) at the time point d) from the control standard voltage. For example, the control standard voltage is 60 V, the guaranteed lifetime is 1000 hours, and the lamp voltage after the guaranteed lifetime has reached 6 hours.
For a 6.0V lamp, the current lamp voltage is 63.6
If it is V, the total lighting time X is obtained by the following formula.

6V / 1000 hours = 3.6V / X

As a result, the current total lighting time X is 600 hours, and the remaining life time is estimated to be 400 hours. By performing the above calculation every time the lamp is turned on, the total lighting time is always updated and the remaining life time is corrected. By correcting the life time as described above, the life of each lamp can be predicted.

The above processing procedure will be described in detail with reference to FIGS. 1, 4 and 2. The life estimation routine in step 57 of FIG. 2 will be described in detail with reference to FIG. In step 31 of FIG. 4, the elapsed time after the start of lamp lighting is measured. Since the lamp power is not stable for 90 seconds after the start of lighting, the life is not predicted. In step 32, the total lighting time of the lamp is measured and stored. In step 33, the output power of the inverter is obtained. The obtained power value is stored in the storage unit 16 in FIG.
If the power value exceeds the value of 3% increase in the power value stored in the above, the remaining life time is predicted from the current lamp voltage value for the rated power of 150 W in step 35 as described above.
Next, at step 36, the lamp status output unit 10 of FIG.
, The predicted life and the current use time are displayed on the display unit 15 to inform the user.

In step 49 of FIG. 2, the lighting time from the lamp lighting command to the actual lighting of the lamp is measured and stored. In step 50, the number of lighting instructions is counted, and the ratio of the number of lightings within 30 seconds to the number of lighting instructions (hereinafter referred to as a lighting success rate) is calculated and stored. Generally, when a lamp is initially used, that is, a new lamp is lit with a lighting probability of almost 100%, but the lighting success rate tends to decrease as the total lighting time increases. In general, the lighting time required from the start of lighting to the lighting tends to be longer than that at the beginning of use. Further, as for the lighting time, a time obtained by adding a fixed ratio to the initial lighting time of each lamp (for example, when the initial lighting time is 1 second, add 9 seconds which is 9 times the value to make 10 seconds). Is a time threshold for determining a normal lamp. This threshold value is a value determined according to the characteristics of each lamp type, and the lamp of the present embodiment has a nine-fold value.
If there is a difference in the lighting success rate for each lamp,
An allowable range is set so that the lamp life is not considered to be exhausted until the ratio of the current lighting success rate to the initial lighting success rate becomes equal to or less than a certain value. This allowable range should be set to a value that takes into account the characteristics of each lamp type, and is set to 1/10 in the present embodiment.

As described above, step 3 in FIG.
If the ratio of the lighting time is 10 seconds or more to the total number of lighting times exceeds 90% in Steps 7 and 38 (Step 37), or the lighting success rate becomes 1/10 or less of the initial lighting success rate. In the case (step 38) or when the power value exceeds the standard value by 10% or more, it is determined that the end of the lamp life is near and a lamp life warning display is performed (step 39).
Next, at step 40, the process returns to the normal power control shown in FIG.

As described above, in addition to the general lamp life guarantee time, the lamp life can be predicted in consideration of the lamp lighting success rate, the lighting time, the power characteristics, and variations among the lamps. When the remaining life has expired, the lamp may be forcibly turned off.

FIGS. 5A and 5B show the storage format of the storage section 16 in this embodiment. Storage unit 16
Stores the standard lamp data and a total of 255
It is possible to store the data of the lamps of the book. FIG.
(A) shows the format of the index part of the storage unit 16 in which data of the standard lamp and 255 lamps are stored. (B) is the actual storage content of the data of each lamp. The number of lighting times, the lighting time required for lighting the lamp, the time until the power value is stabilized, the lighting success rate, the total lighting time, and the like can be stored up to 9999 times for each lighting number.

[0029]

According to the discharge lamp lighting device of the present invention, a lamp power transition characteristic detection / storage unit in the controller, a total lighting count / time measuring unit, a lighting success rate measuring unit for lighting operation, and a lighting time By using the measuring unit, it is possible to predict the life in consideration of not only the lighting time but also various characteristics of individual lamps, changes in lighting characteristics, and the like. In addition, by displaying the result of the life prediction on the display unit, a warning is given to the user, and there is an effect that sudden explosion of the lamp and destruction of the control circuit can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram of a discharge lamp lighting device according to an embodiment of the present invention.

FIG. 2 is a flowchart of power control of the discharge lamp lighting device according to the embodiment of the present invention.

FIG. 3 is a characteristic diagram of a lamp used in an embodiment of the present invention.

FIG. 4 is a flowchart of a life estimation routine of the discharge lamp lighting device according to the embodiment of the present invention.

FIG. 5A is a diagram illustrating a format of an index portion of a storage unit. FIG. 5B is a diagram illustrating storage contents of a storage unit that stores a lamp lighting state of the discharge lamp lighting device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 2 Inverter part 3 Lamp 4, 17 switch 5 Lighting circuit 6 Controller 7 Current / voltage detection part 8 Temperature detection part 9 Power adjustment part 10 Total lighting number / time measurement part 11 Power transition characteristic detection / storage part 12 Inverter control Unit 13 Lighting success rate measuring unit 14 Lamp status output unit 15 Display unit 16 Storage unit 22 High voltage generation circuit

Claims (3)

[Claims] An inverter unit that converts DC power supplied from a DC power supply into AC power and applies the AC power to a discharge lamp; an inverter control unit that adjusts power supplied to the discharge lamp according to a control input; A power transition characteristic detecting unit for the discharge lamp that detects a temporal change in the power supplied to the discharge lamp, wherein when the value of the power supplied to the discharge lamp exceeds a predetermined value, the inverter According to a predetermined control value of the control unit,
A discharge lamp lighting device for predicting the life time of a discharge lamp. 2. An inverter unit for converting DC power supplied from a DC power supply to AC power and applying the AC power to a discharge lamp, and a current / voltage detection unit for detecting a current and a voltage applied from the inverter unit to the discharge lamp. When the power obtained from the current value and the voltage value detected by the current / voltage detection unit exceeds a specified power value of the discharge lamp by a predetermined ratio, the standard voltage of the discharge lamp is set to V1, a predetermined guarantee. The voltage after the life time T has elapsed is V
2. When the detection voltage of the current / voltage detection unit is V,
A controller that calculates the total lighting time X by calculating the following equation (V2−V1) / T = (V−V1) / X, and calculates the remaining life time of the difference between the total lighting time X and the guaranteed life time T. And a discharge lamp lighting device. 3. A lighting time measuring unit for a discharge lamp for measuring a lighting time required for a voltage and a current applied from the inverter unit to the discharge lamp to reach respective predetermined values at the time of lighting. It is determined that the lighting of the discharge lamp has succeeded when the discharge lamp has reached the energized state, and the lighting success rate measurement unit for measuring the success rate of the discharge lamp, and the power value supplied to the discharge lamp in the lighting state is determined in advance. A power transition characteristic detection storage unit that detects that a predetermined value has been exceeded, wherein the lighting time exceeds a predetermined value, the power value exceeds a predetermined value, and the lighting success rate is The discharge lamp lighting device according to claim 1, wherein a warning indicating that the life of the discharge lamp has reached is issued when at least one of the values below a predetermined value occurs.