JP4822169B2 - High pressure discharge lamp lighting device - Google Patents

Description

  The present invention relates to a high pressure discharge lamp lighting device for dimming and lighting a high pressure discharge lamp.

  In recent years, dimming lighting of high-pressure discharge lamps has been studied. As a lighting circuit for dimming and lighting a high pressure discharge lamp, FIG. 1 shows a circuit configuration of a high pressure discharge lamp lighting device. The high pressure discharge lamp lighting device includes a DC power source 1, a step-down chopper circuit 2, a full bridge circuit 3, an igniter circuit 4, a PWM control circuit 5, a full bridge control circuit 6, and an igniter control circuit 7. The PWM control circuit 5 receives a dimming signal from an external dimming signal oscillation circuit 8. The DC power source 1 may be a rectified and smoothed commercial AC power source. Further, the apparatus detects a voltage of the high-voltage discharge lamp L1 (hereinafter referred to as “lamp voltage”), a voltage detection circuit including resistors R1 and R2, and a current flowing through the high-pressure discharge lamp L1 (hereinafter referred to as “lamp current”). A current detection circuit including a resistor R3 for detection is provided.

  The PWM control circuit 5 controls the switching element Q <b> 1 of the step-down chopper circuit 2 to convert the output current of the DC power supply 1 to an appropriate value, and then outputs it to the full bridge circuit 3. The full bridge control circuit 6 alternately turns on the switching elements Q2, Q5 and Q3, Q4 of the full bridge circuit 3 at a frequency of about 60 Hz to 400 Hz, and outputs a low frequency rectangular wave to the high pressure discharge lamp L1. The igniter control circuit 7 applies a voltage of several hundred volts to the primary winding N1 of the transformer T1 before starting the high pressure discharge lamp L1, thereby causing a high voltage pulse (several kV to several kV) to the secondary winding N2. 10 kV) and the high pressure discharge lamp L1 is started. After starting the high pressure discharge lamp L1, the igniter control circuit 7 stops its operation.

  When a dimming signal is input to the PWM control circuit 5 from the external dimming signal oscillation circuit 8, the PWM control device 5 controls the power of the high-pressure discharge lamp L1 by controlling the step-down chopper circuit 2. Specifically, in the PWM control device 5, the power to be input to the high-pressure discharge lamp L <b> 1 (hereinafter referred to as “a”) with respect to the dimming degree indicated by the input dimming signal and the lamp voltage detected by the lamp voltage detection circuit. (Referred to as “lamp power”), and a calculation (for example, assignment by a program table or the like) for further deriving the lamp current necessary for turning on the lamp power is performed in the PWM controller 5, and the lamp current, In this case, the duty of Q1 of the step-down chopper circuit 2 is controlled so that the lamp power is supplied. Here, the current detection circuit (R3) is not necessary when the entire circuit is operated in a feed-forward manner as an open loop, but is necessary when the switching of Q1 is controlled by feeding back the lamp current or the lamp power. The lamp power is calculated by multiplying the lamp voltage value by the lamp current value.

FIG. 9 shows a conventional example of the relationship between lamp power input to the lamp voltage detected as described above (hereinafter referred to as “power characteristic” or “power curve”) for the high-pressure discharge lamp L1. The horizontal axis represents the lamp voltage of the high pressure discharge lamp, and the vertical axis represents the ratio from the rated power of the high pressure discharge lamp. The power curve when all the lights are on is (a), the power curve when 80% dimming is (b), and the power curve when 60% dimming is (c). Generally, this power curve (particularly the power curve (a)) is determined in consideration of the life of the high-pressure discharge lamp. In other words, when the lamp life is advanced and the lamp voltage is increased, the lamp power to be applied is reduced to some extent to prevent the life from being advanced. In general, the material of the arc tube bulb constituting the high pressure discharge lamp is roughly classified into those using quartz glass and those using ceramic materials. The quartz glass type is known to be susceptible to the lamp life and light emission characteristics of the bulb temperature (lamp power) due to its structure, but the ceramic material type is less susceptible to the influence. Yes.

In this power characteristic, when the high pressure discharge lamp at point A of the all-light lighting power curve is instantaneously dimmed by 80%, that is, when the lamp current is to be reduced to 80% in the state of the lamp voltage at point A. Because of the negative characteristics of the high-pressure discharge lamp, the lamp voltage once rises to the point B and then decreases to the point C, so that the state of the high-pressure discharge lamp is stabilized.
Further, when the high pressure discharge lamp at point A of the all-light lighting power curve is dimmed 60% instantaneously, it moves from point A to point D and then stabilizes at point E. As the dimming level becomes deeper in this way, the temporary lamp voltage rise value becomes larger. Depending on individual variations of the high-pressure discharge lamp and changes in the discharge lamp state during the life of the discharge lamp, the discharge at the power at point D Cannot be maintained, and may disappear.

  As a specific example, it is assumed that the rated power of the high-pressure discharge lamp L1 is 100 W, the lamp voltage at the time of all light (at 100 W lighting / point A) is 92 V, and the lamp current is 1.09 A (= 100 W / 92 V). . In the case of 60% dimming (60W lighting), the finally stable point E is the lamp voltage 74V and the lamp current 0.81A (= 60W / 74V). However, if an attempt is made to instantaneously set the lamp current to 0.81 A from the state of the lamp voltage 92 V and the lamp current 1.09 A, the lamp voltage will rise to 104 V at point D due to the load characteristics of the lamp. Here, a lamp current of 0.46 A (= 48 W / 104 V) flows to supply the lamp power of 48 W set for the lamp voltage of 104 V. The dimming degree is described as being proportional to the lamp power.

Here, it is assumed that the life of the high-pressure discharge lamp L1 has advanced. Usually, the lamp voltage rises as the life of a high pressure discharge lamp increases, and depending on the type of the high pressure discharge lamp, when it reaches 130 to 150 V or more when all the lights are lit, it is determined that the end of life is reached. In the case where the lighting state at the time of all the lights is A ′, that is, the lamp having a lamp voltage of 120 V, a lamp power of 94 W, and a lamp current of 0.78 A is dimmed by 60%, the finally stable point E ′ is a lamp power of 56 W (94 W 60%), the lamp voltage is 100 V, and the lamp current is 0.56 A (= 56 W / 100 V). However, if an attempt is made to instantaneously set the lamp current to 0.56 A from the state where the lamp voltage is 120 V and the lamp current is 0.78 A, the lamp voltage will increase to near 135 V due to the load characteristics of the lamp. If the curve (c) of the graph is virtually extended and calculated, the lamp current with respect to the lamp voltage 135V becomes about 0.1 A, and it is difficult to stably maintain the discharge.
In order to easily understand the shape of the power characteristic curve, the graph of FIG. 9 is drawn with the curve extended to the point where the lamp voltage becomes 0V. Shall apply.

In order to solve this problem, for example, in Patent Document 1, in the case of a range that disappears when dimming instantaneously, dimming is performed instantaneously to a range where it does not disappear, and then a predetermined dimming level at a dimming speed at which it does not easily disappear The light is gradually dimmed.
Japanese Patent No. 3306904

  In the above control, in the case of a range that turns off when dimming instantaneously, the light is dimmed instantaneously to a range where it does not go off, and then gradually dimmed to a predetermined dimming level at a dimming speed at which it does not easily turn off. Therefore, when the dimming level is increased, it takes time until the light quantity of the discharge lamp is stabilized, which is not suitable for an application in which the dimming level is frequently changed.

  A first aspect of the present invention is a power supply circuit that supplies AC power to a high-pressure discharge lamp, a lamp voltage detection circuit that detects a lamp voltage of the high-pressure discharge lamp, and a dimming signal received from the outside to adjust the dimming degree A high pressure discharge lamp lighting device comprising a control circuit for determining and controlling lamp power supplied from a power supply circuit according to a dimming degree and a detected lamp voltage, wherein the control circuit is at least equal to or less than a predetermined dimming degree In the depth (darkness), in the range where the detected lamp voltage is equal to or higher than a predetermined voltage and equal to or lower than the maximum lamp voltage that can be taken by the high-pressure discharge lamp, the lamp power with respect to the detected lamp voltage at the same dimming degree The power supply circuit is controlled so as to increase monotonously. Here, the predetermined voltage is the minimum lamp voltage that the high-pressure discharge lamp can take. The predetermined dimming degree is defined as all light. Furthermore, the ratio of increasing the lamp power with respect to the increase in the detected lamp voltage set for each dimming degree is set to increase as the dimming degree is deeper.

  The second aspect of the present invention is an illumination device comprising the high pressure discharge lamp lighting device according to the first aspect, a housing containing the high pressure discharge lamp lighting device, a high pressure discharge lamp, and a reflector to which the high pressure discharge lamp is attached. .

  According to the high pressure discharge lamp lighting device of the present invention, when the high pressure discharge lamp is turned on, the lamp power is controlled to increase as the lamp voltage increases. , Temporary rise in lamp voltage can be kept low, and extinction can be suppressed. Therefore, the light control level can be changed frequently.

Next, embodiments will be described.
FIG. 2 is a power characteristic diagram according to the present invention. The horizontal axis represents the lamp voltage of the high pressure discharge lamp, and the vertical axis represents the ratio from the rated power of the high pressure discharge lamp. The power characteristic at the time of all light lighting is (a), the power characteristic at 80% dimming is (b), and the power characteristic at 60% dimming is (c). The lighting circuit shown in FIG. 1 described above is used. Since the feature of the present invention is the control mode during dimming, a general circuit configuration may be used for the hardware part of the circuit configuration. Further, the lamp voltage range of each line of the power characteristic may be any value that includes a lamp voltage value that can be taken by the high-pressure discharge lamp to be used. In general, the minimum value that can be taken by the lamp voltage is the lamp voltage immediately after the start of lamp operation, and the maximum value is the lamp voltage at the end of the lamp life (usually, when the detected lamp voltage reaches its upper limit value, the lamp is turned off by a protection operation. Therefore, the lamp voltage to be protected may be defined as the maximum value).

Here, the high-pressure discharge lamp L1 with a rated power of 100 W whose life has not advanced so much will be specifically described as an example. The point C of the lamp power 80W, which is stable at 80% dimming (88V, 0.90A) when the lamp voltage is 100V, the lamp current is 100V at the total light point A (lamp power 100W), and 60% dimming It is assumed that the point E of the stable lamp power 60 W is (80 V, 0.75 A).
Here, when the light intensity shifts to 60% dimming instantly from the whole light, the lamp voltage rises momentarily to point D (lamp voltage 115V), and the set lamp power corresponding to this lamp voltage is about 68 W, so the lamp current Becomes 0.59A. Then, the lighting state moves and reaches point E.

Here, let us consider a case where the life of the high-pressure discharge lamp L1 has progressed and, for example, the lighting state at the time of all lights becomes point A ′, that is, the lamp voltage 120V, the lamp power 104W, and the lamp current 0.87A. When the point A ′ is dimmed by 60%, the finally stable point E ′ is a lamp power of 62 W (60% of 104 W), a lamp voltage of 90 V, and a lamp current of 0.69 A. When an attempt is made to instantaneously set the lamp current to 0.69 A from the state of the lamp voltage 120 V and the lamp current 0.87 A (point A ′), the lamp voltage is close to 135 V at the point D ′ due to the load characteristics of the lamp. Even if it rises for a moment, since the lamp power is set to be close to 70 W, the lamp current becomes 0.52 A, which is a current value that can sufficiently maintain the discharge.
In addition, although demonstrated using the coordinate in a graph, the graph of an electric power characteristic is a conceptual diagram, and does not strictly follow description of a graph and the numerical value which it shows. Furthermore, for the convenience of explanation, the rated power of the high-pressure discharge lamp L1 is exemplarily set to 100 W, but other rated power may be used.

  FIG. 3 shows another embodiment of a power characteristic diagram according to the present invention. In this embodiment, when the high-pressure discharge lamp is turned on, the lamp power is controlled to increase as the lamp voltage increases, and as the dimming level increases, the lamp power increase rate (inclination) as the lamp voltage increases. ) Is controlled so as to increase. As a result, it is possible to further strengthen countermeasures for disappearance at low dimming levels.

  According to the power characteristics as shown in FIG. 2 and FIG. 3, when the high-pressure discharge lamp is turned on, the lamp power is controlled to increase as the lamp voltage rises. However, the temporary rise of the lamp voltage can be suppressed to a low level, and the extinction can be suppressed. Even if the lamp voltage rises, the lamp power set for the lamp voltage is set to be larger than that of the conventional lamp, so that a large amount of lamp current can flow, contributing to prevention of extinction. Moreover, since the disappearance avoidance measure of delaying the dimming transition operation as in Patent Document 1 is not used, it is possible to shift to a desired dimming degree in a short time.

  FIG. 4 is a diagram showing another embodiment. 2 and 3 show that the slope of the power characteristic monotonically increases with respect to the lamp voltage in all dimming degrees, but in FIG. 4A, the slope is monotonous only for a predetermined dimming degree or less. In the figure, a constant power control is performed by eliminating the inclination in a range brighter than a predetermined dimming degree. In FIG. 4A, for example, the power is constant in a range brighter than 80% dimming (for example, 90%), and below 80%, a monotonically increasing slope is provided as in FIGS. Further, as shown in FIG. 4 (b), the inclination of the power characteristic may be eliminated only for all light, or an upper limit value is provided for the lamp power setting value as shown in FIG. 4 (c). You may make it not. The upper limit value may not be a value with a lamp power ratio of 100%. In this case, the point F in the figure may be defined by the lamp voltage (for example, constant at a certain lamp voltage or higher), or defined by the lamp power (for example, constant at a certain lamp power or higher). May be.

  Furthermore, as shown in FIG. 5, in the dimming degree that does not cause a problem in dimming (for example, in the case of all light), a degree of freedom is provided in the inclination of the power characteristic so as to approximate the curve as shown in FIG. Also good. Also in this case, the inclination of the power characteristic may be increased as the dimming degree is deeper.

  According to the embodiment shown in FIGS. 4 to 5, the increase in lamp power is suppressed to some extent when the lamp voltage is high. Thereby, it is possible to ensure to some extent both the dimming function and the suppression of the lamp life. When the high-pressure discharge lamp L1 has the above-described ceramic material bulb, even if the lamp power is slightly increased, there is little effect on the life, so the power characteristics as shown in FIG. 2 or FIG. Is more preferable.

  Moreover, the power characteristic of FIG. 6 is shown as an example applicable when a countermeasure for extinction is to be taken only when the lamp voltage is high. The difference between the power characteristic diagram of FIG. 6 and the power characteristic diagram of FIG. 9 is that the lamp power set with respect to the lamp voltage increases again in the high lamp voltage region. If this power characteristic is used, the minimum necessary extinction prevention effect can be obtained.

In the embodiment, the lower limit value of the dimming level is set to 60%, but the lower limit value of the dimming level may be different depending on the individual characteristics of the high pressure discharge lamp.
Further, the circuit configuration for achieving the power characteristics shown in FIGS. 2 to 6 may be other than the circuit configuration shown in FIG. 1 as long as the AC power supplied to the lamp can be appropriately controlled.
Further, in FIGS. 2 to 6, the power characteristic is terminated to one line in the region where the lamp voltage is low, but it may not be terminated as such. In any power characteristic diagram of any of the embodiments, the lamp current to be input is set to be within the range of the rated current of the high-pressure discharge lamp to be used.

  In summary, the main point of the present invention is the control of lamp power in the low dimming degree or the control of lamp power in the high lamp voltage range. Therefore, as shown in FIG. 7, in the low dimming and high lamp voltage range, the power If the characteristic has a positive slope (the lamp power tends to increase with respect to the lamp voltage), the minimum and most important object of the present invention such as prevention of extinction during instantaneous dimming can be achieved. Accordingly, the power characteristics of the region surrounded by the broken line in FIG. 7 may be, for example, as shown in FIG. 2-6 or FIG. 9 of the conventional example, and any power characteristic falls within the scope of the present invention. included.

  Here, as another embodiment, a lighting device using the above-described high-pressure discharge lamp lighting device is shown in FIG. In the figure, 11 is a reflector to which the high-pressure discharge lamp L1 is attached, 12 is a housing containing the high-pressure discharge lamp lighting device, and the output line from the high-pressure discharge lamp lighting device is connected to the electrode of the high-pressure discharge lamp L1. . In addition, the figure is a schematic illustration of the embodiment, and the dimensions, arrangement, and the like are not as illustrated.

  In the present embodiment, since the high pressure discharge lamp lighting device that reliably prevents the light extinction due to the instantaneous dimming operation and can quickly shift to the desired dimming degree is mounted, the reliability is high and frequent Therefore, it is possible to obtain a lighting device that is easy to use even in applications where the light control operation is performed.

  The present invention can be applied to general lighting fixtures, projectors, and the like.

It is a figure which shows the circuit structure of a high pressure discharge lamp lighting device. It is a figure which shows the electric power characteristic of embodiment of this invention. It is a figure which shows the electric power characteristic of another embodiment of this invention. It is a figure which shows the electric power characteristic of another embodiment of this invention. It is a figure which shows the electric power characteristic of another embodiment of this invention. It is a figure which shows the electric power characteristic of another embodiment of this invention. It is a figure which shows the electric power characteristic of another embodiment of this invention. It is a figure which shows the electric power characteristic of another embodiment of this invention. It is a figure which shows the electric power characteristic of another embodiment of this invention. It is a figure which shows the light source device of this invention. It is a figure which shows the power characteristic of a prior art example.

Explanation of symbols

1. 1. DC power supply 2. Step-down chopper circuit 3. Full bridge circuit 4. Igniter circuit PWM control circuit 6. 6. Full bridge control circuit 7. Igniter control circuit Dimming signal transmission circuit L1. High pressure discharge lamps R1, R2, R3. Resistance 11. Reflector 12. Enclosure

Claims (5)

A power supply circuit that supplies AC power to the high-pressure discharge lamp, a lamp voltage detection circuit that detects the lamp voltage of the high-pressure discharge lamp, and a dimming signal received from the outside to determine the dimming level and the dimming level and detection A high pressure discharge lamp lighting device comprising a control circuit for controlling lamp power supplied from the power supply circuit according to the lamp voltage,
The control circuit sets the lamp power with respect to the lamp voltage to be at least the first voltage and less than the second voltage for each dimming degree having a depth (darkness) of at least a predetermined dimming degree. The range is monotonously increased, the range is monotonically decreased in the range where the lamp voltage is greater than or equal to the second voltage and less than the third voltage, and the maximum voltage that the lamp voltage is greater than or equal to the third lamp voltage and the high pressure discharge lamp can take. A high pressure discharge lamp lighting device that controls the power supply circuit so as to increase monotonously in a range that is lower than the lamp voltage.
A power supply circuit that supplies AC power to the high-pressure discharge lamp, a lamp voltage detection circuit that detects the lamp voltage of the high-pressure discharge lamp, and a dimming signal received from the outside to determine the dimming level and the dimming level and detection A high pressure discharge lamp lighting device comprising a control circuit for controlling lamp power supplied from the power supply circuit according to the lamp voltage,
For each dimming level with a depth (darkness) less than a predetermined dimming level, the control circuit uses the lamp power with respect to the lamp voltage as the maximum that the lamp voltage is equal to or higher than the predetermined voltage and the high-pressure discharge lamp can take. The lamp power is monotonously increased in the range of the lamp voltage or less, and for each dimming degree equal to or higher than the predetermined dimming degree, the lamp power with respect to the lamp voltage is equal to or higher than the first voltage and lower than the second voltage. It is monotonously increased in a range, a high pressure discharge lamp lighting device for controlling so that said power supply circuit is monotonically decreasing in the range where the lamp voltage is less than voltage or more and said maximum lamp voltage of the second.
3. The high pressure discharge lamp lighting device according to claim 1, wherein the predetermined dimming degree is all light.
The high pressure discharge lamp lighting device according to claim 2 or 3, characterized in that a ratio of increasing the lamp power with respect to an increase in the lamp voltage set for each dimming degree is larger as the dimming degree is deeper. High pressure discharge lamp lighting device.
  An illumination device comprising the high pressure discharge lamp lighting device according to any one of claims 1 to 4, a casing enclosing the high pressure discharge lamp lighting device, a high pressure discharge lamp, and a reflector to which the high pressure discharge lamp is attached.

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