JPH10162975A - Discharge lamp control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp control circuit capable of realizing stable lighting of a discharge lamp, reducing an excess overload state, and preventing the breakage and short life of the discharge lamp. SOLUTION: A discharge lamp control circuit consists of an inverter means 2 for supplying a rectangular wave AC voltage to a discharge lamp 3, a lamp current detecting means 4 for detecting lamp current flowing through the discharge lamp 3, a lamp voltage detecting means 5 for detecting lamp voltage applied to the discharge lamp 3, and a control means 6 for controlling power supplied to the discharge lamp 3 based on the output signals of the lamp current detecting means 4 and the lamp voltage detecting means 5, and supplies the initial power higher than power to be supplied in the stable lighting of the discharge lamp 3 in the start of lighting of the discharge lamp 3. A temperature sensor 7 for detecting temperature in the vicinity of the discharge lamp 3 in the start of lighting of the discharge lamp 3 is arranged, and the control means decides the time for supplying the initial power based on the temperature detected with the temperature sensor 7.

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.

[0002]

2. Description of the Related Art Conventionally, in a discharge lamp lighting device of this type, as shown in FIG. So that the power supply of the discharge lamp 3 becomes a predetermined value.
The control unit 6 controls the output of the inverter unit 2 that supplies power to the inverter unit 2. The control means 6 controls the power supply from the inverter means 2 to the discharge lamp 3 immediately after the start to have a preset value. At this time, if the power supplied to the discharge lamp 3 is constant even if the temperature near the discharge lamp changes, if the discharge lamp 3 is at a low temperature, the power for raising the temperature of the discharge lamp 3 is sufficient. In some cases, the lamp could not be lit because of insufficient pressure in the lamp tube. Therefore, when the discharge lamp is turned on, an initial power higher than that in the stable lighting state is supplied for a certain period of time, so that the discharge lamp 3 is reliably turned on.

[0003]

However, in the discharge lamp lighting device having the above-mentioned structure, the initial power at the time of lighting the discharge lamp exerts an excessive stress on the discharge lamp 3, so that the discharge lamp 3 is damaged or has a short life. Was the cause.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to realize stable lighting of a discharge lamp, reduce an excessive overload state, and to damage the discharge lamp. And to provide a discharge lamp control circuit for preventing a short life.

[0005]

According to the first aspect of the present invention,
Inverter means for supplying a rectangular wave AC voltage to the discharge lamp, lamp current detection means for detecting a lamp current flowing through the discharge lamp, lamp voltage detection means for detecting a lamp voltage applied to the discharge lamp, Control means for controlling power supplied to the discharge lamp in accordance with an output signal of the lamp current detection means and the lamp voltage detection means,
In a discharge lamp control circuit configured to supply an initial power higher than the power supplied at the time of stable lighting of the discharge lamp at the start of lighting of the discharge lamp, a temperature near the discharge lamp at the start of lighting of the discharge lamp is detected. The control unit determines the time for supplying the initial power based on the temperature detected by the temperature sensor.

According to a second aspect of the present invention, in the discharge lamp control circuit of the first aspect, an A / D converter for converting an analog output signal of the lamp current detector and the lamp voltage detector into a digital output signal is provided. In addition, the electric power supplied to the discharge lamp is controlled by the control means in accordance with the digital output signal.

According to a third aspect of the present invention, in the discharge lamp control circuit according to the first or second aspect, a difference between a temperature near the discharge lamp and a predetermined temperature and a time for supplying initial power to the discharge lamp are provided. Is stored in the control means in advance,
A supply time of the initial power to be supplied to the discharge lamp is calculated from a difference between the temperature detected by the temperature sensor and the predetermined temperature.

According to a third aspect of the present invention, in the discharge lamp control circuit according to any one of the first to third aspects, the initial power supplied to the discharge lamp can be arbitrarily set. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a discharge lamp control circuit according to one embodiment of the present invention. Reference numeral 1 denotes a DC power supply, which functions as a power supply for a discharge lamp control circuit. Reference numeral 2 denotes an inverter, which converts a DC voltage supplied from the DC power supply 1 into a rectangular wave AC voltage and supplies the rectangular wave AC voltage to the discharge lamp 3. Reference numeral 4 denotes a lamp current detecting means for detecting a lamp current flowing through the discharge lamp 3. Reference numeral 5 denotes lamp voltage detecting means for detecting a voltage applied to the discharge lamp 3. Reference numeral 6 denotes a control unit which is supplied to the discharge lamp 3 in accordance with output signals from the lamp current detection unit 4 and the lamp voltage detection unit 5 and the temperature near the discharge lamp 3 when the discharge lamp is turned on detected by the temperature sensor 7. To control power.

Next, the operation of this embodiment will be described. FIG. 2 is a graph showing the amount of power supplied to the discharge lamp from the start of lighting to the stable state in the present embodiment. Usually, when the discharge lamp is turned on, the discharge lamp 3 needs to reach a predetermined light emission amount quickly. For this reason, at the start of lighting of the discharge lamp 3, the initial power W1 which is overloaded compared to the power W0 at the time of normal lighting is supplied to the discharge lamp, and the power supplied after a lapse of some time is reduced. When the light emission amount is reached, the power W0 during normal lighting is supplied.

First, the temperature near the discharge lamp is detected by the temperature sensor 7 before starting the lighting. Next, the control means 6 determines data on the detected temperature from among a plurality of preset data regarding the relationship between the temperature near the discharge lamp and the supply time of the initial power. Then, while detecting the current flowing through the discharge lamp 3 and the applied voltage, the initial power W is supplied to the discharge lamp 3 for a predetermined time according to the determined data.
Supply 1

As shown in FIG. 2, if the detected temperature is higher than the normal temperature, the time for supplying the initial power W1 is shortened, and the excess overload state is reduced. Conversely, when the temperature is low, the time for supplying the initial power W1 is increased, the amount of heat generated by the discharge lamp 3 is increased, and the pressure in the tube is increased. Thereafter, control is performed so as to supply W0 during normal lighting.

According to this embodiment, it is possible to control the time for supplying the initial power which is overloaded based on the temperature near the discharge lamp while supplying the initial power required for lighting the discharge lamp, It is possible to provide a discharge lamp control circuit that realizes stable lighting of the discharge lamp, can reduce an excessive overload state, and prevents breakage and short life of the discharge lamp.

FIG. 3 is a schematic configuration diagram of a discharge lamp control circuit according to another embodiment of the present invention. In the present embodiment, FIG.
A / D conversion means is added to the discharge lamp control circuit shown in (1), the analog output signals of the lamp current detection means 4 and the lamp voltage detection means 5 are converted into digital output signals, and the control means is controlled in accordance with the converted digital output signals. 6 controls the power supplied to the discharge lamp 3.

According to this embodiment, the digital signal is easier and more flexible in processing the digital signal than the analog signal. Thus, highly accurate signal processing can be performed.

FIG. 4 is a schematic configuration diagram of a discharge lamp control circuit according to another embodiment of the present invention. In the present embodiment, FIG.
The calculation means 9 is added to the control means 6 of the discharge lamp control circuit shown in FIG. The control means 6 holds in advance the relationship between the difference between the temperature near the discharge lamp and the predetermined temperature and the time for supplying the initial power to the discharge lamp 3.

The operation of this embodiment will be described. FIG.
Is a graph showing the amount of power supplied to the discharge lamp from the start of lighting to the stable state in the present embodiment. For convenience of explanation, A section in which the initial power W1 is supplied immediately after the discharge lamp 3 is turned on, B section in a transient lighting state from the A section to the normal lighting state, and C section in which the power W0 is supplied and in the normal lighting state. Think in three parts. Before the start of lighting, the temperature near the discharge lamp is detected by the temperature sensor 7, and when the detected temperature is lower than the predetermined temperature, a correction value is obtained by the calculating means 9 from the difference between the detected temperature and the predetermined temperature. With the correction value, the time of the section A is extended by the correction value as shown in FIG. As a result, the amount of power supplied to the discharge lamp 3 at low temperatures is as shown in FIG. 5A, and the control means 6 supplies power to the discharge lamp 3 according to this. When the temperature near the discharge lamp at the start of lighting is higher than the predetermined temperature, the correction value is calculated by the same procedure as shown in FIG. 5B, and the time of the section A is shortened by the correction value. According to this result, the control unit 6 supplies power to the discharge lamp 3.

According to the present embodiment, it is possible to reduce the data capacity of the relationship between the temperature near the discharge lamp held by the control means 6 and the supply time of the initial power, so that the cost can be reduced. Data can be easily set and changed.

If the initial power supplied to the discharge lamp 3 can be set arbitrarily, the optimum initial power can be easily set according to the standard of the discharge lamp 3. For this reason, the initial power required at the time of lighting the discharge lamp can be optimized, and unnecessary overload can be prevented from being applied to the discharge lamp, and power can be saved.

[0020]

As described above, according to the first aspect of the present invention, the inverter means for supplying a rectangular wave AC voltage to the discharge lamp, and the lamp current detection means for detecting the lamp current flowing through the discharge lamp Lamp voltage detecting means for detecting a lamp voltage applied to the discharge lamp; and control means for controlling power supplied to the discharge lamp in accordance with output signals of the lamp current detecting means and the lamp voltage detecting means. In a discharge lamp control circuit configured to supply at the start of lighting of the discharge lamp a higher initial power than the power supplied at the time of stable lighting of the discharge lamp, the vicinity of the discharge lamp at the start of lighting of the discharge lamp Temperature sensor for detecting the temperature of the discharge lamp, and the control means determines the time for supplying the initial power based on the temperature detected by the temperature sensor. It is possible to control the time for supplying the initial power based on the temperature near the discharge lamp while supplying the required initial power, and realize stable lighting of the discharge lamp and reduce unnecessary overload conditions. Thus, a discharge lamp control circuit for preventing the discharge lamp from being damaged or having a short life can be provided.

According to the second aspect of the present invention, the first aspect is provided.
In the invention described in the claims, A / D conversion means for converting analog output signals of the lamp current detection means and the lamp voltage detection means into digital output signals is added, and the control means controls the discharge lamp in accordance with the digital output signals. Since the power to be supplied to is controlled, since the digital signal is easier and more flexible in signal processing than the analog signal, the processing of the digital output signal in the control means becomes easier, Highly accurate signal processing can be performed.

According to the third aspect of the present invention, there is provided the first aspect.
Alternatively, in the invention according to claim 2, a relationship between a difference between a temperature near the discharge lamp and a predetermined temperature and a time for supplying initial power to the discharge lamp is stored in the control unit in advance, and the temperature sensor detects Since the supply time of the initial power to be supplied to the discharge lamp is calculated from the difference between the detected temperature and the predetermined temperature, the temperature near the discharge lamp and the supply time of the initial power held by the control means are calculated. Since it is possible to reduce the data capacity for the relationship, the cost can be reduced, and the data can be easily set and changed.

According to a third aspect of the present invention, in the discharge lamp control circuit according to the first to third aspects, the initial power to be supplied to the discharge lamp can be arbitrarily set. It is possible to optimize the initial power, to prevent unnecessary overload on the lamp, and to save power.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a discharge lamp control circuit according to an embodiment of the present invention.

FIG. 2 is a graph showing the amount of power supplied to a discharge lamp from the start of lighting to a stable state in the present embodiment.

FIG. 3 is a schematic configuration diagram of a discharge lamp control circuit according to another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a discharge lamp control circuit according to another embodiment of the present invention.

FIG. 5 is a graph showing the amount of electric power supplied to the discharge lamp from the start of lighting to the stable state in the embodiment.

FIG. 6 is a schematic configuration diagram of a conventional discharge lamp control circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 2 Inverter means 3 Discharge lamp 4 Lamp current detection means 5 Lamp voltage detection means 6 Control means 7 Temperature sensor 8 A / D conversion means 9 Calculation means

Claims (4)

[Claims] 1. Inverter means for supplying a rectangular wave AC voltage to a discharge lamp, lamp current detection means for detecting a lamp current flowing through the discharge lamp, and lamp voltage for detecting a lamp voltage applied to the discharge lamp Detection means, and control means for controlling the power supplied to the discharge lamp in accordance with the output signals of the lamp current detection means and the lamp voltage detection means, In a discharge lamp control circuit configured to supply high initial power at the start of lighting of the discharge lamp, a temperature sensor for detecting a temperature near the discharge lamp at the start of lighting of the discharge lamp is added, and the control unit includes a temperature sensor. A discharge lamp control circuit, wherein a time for supplying initial power is determined based on a temperature detected by a sensor. 2. An A / D converter for converting analog output signals of the lamp current detecting means and the lamp voltage detecting means into a digital output signal, wherein the control means controls the discharge lamp in accordance with the digital output signal. The discharge lamp control circuit according to claim 1, wherein the power supplied to the discharge lamp is controlled. 3. A relationship between a difference between a temperature near the discharge lamp and a predetermined temperature and a time for supplying initial power to the discharge lamp is stored in the control unit in advance, and a temperature detected by the temperature sensor is stored. 3. The discharge lamp control circuit according to claim 1, wherein a supply time of an initial power to be supplied to the discharge lamp is calculated from a difference between the discharge lamp and the predetermined temperature. 4. The discharge lamp control circuit according to claim 1, wherein an initial power supplied to said discharge lamp can be arbitrarily set.