JP2001284079A - Device for discharge lamp, discharge lamp lighting device and illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a discharge lamp lighting device from outbreak of fuming and ignition caused by an unusual generation of heat resulted from continued unusual discharge; which is generated at the outer surface of a casing along the crack between electrodes with the same polarity, which is formed on one electrode of a pair of outer electrodes; or generated at the outer surface of a casing when the insulation between the electrodes, having different polarity from each other, is deteriorated. SOLUTION: For a discharge lamp 1 having a pair of electrodes 3, 4, generating discharge inside a transparent bulb 2, on the outer surface of the bulb, when the insulation between a pair of outer electrodes 3, 4 is deteriorated, an unusual discharge is generated between the outer electrodes along the outer surface of the transparent bulb. Thereupon, a disorder detecting means 12 detects the unusual discharge, and the disorder detecting means restricts the output of a high frequency generating device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a discharge lamp, a lighting device for a discharge lamp, and a lighting device for lighting a discharge lamp having at least one electrode for generating a discharge outside a translucent bulb with high frequency power. About.

2. Description of the Related Art Conventionally, this type of apparatus has been disclosed in JP-A-11-311.
Japanese Patent Application Publication No. 07292 is proposed. Hereinafter, this prior art will be described with reference to FIGS.

FIG. 6 is a circuit diagram showing an example of a conventional discharge lamp lighting device, FIG. 7 is a sectional view showing an example of a conventional discharge lamp, and FIG.
FIG. 9 is a developed view of the light-transmitting bulb and the external electrode, and FIG. 9 is a waveform diagram showing the lamp current of the discharge lamp.

In this prior art, as shown in FIG. 6, a discharge lamp 60 is lit by a high frequency generator 61 composed of a single-type transistor inverter. The output voltage of the high frequency generator 61 is an intermittent pulse voltage. As shown in FIGS. 7 and 8, the discharge lamp 60 includes a light-transmitting bulb 62, external electrodes 63 and 64 provided on the outer surface of the bulb 62 at a distance from each other, and a light-transmitting bulb 62.
And an electrically insulating and translucent sheet 65 covering the external electrodes 63 and 64. Further, the discharge lamp 60 has a fluorescent layer 67 with a predetermined range of apertures 66 left on the inner surface of the bulb.
And a rare gas is sealed in the valve 62.

The external electrodes 63 and 64 have deformed portions 63A and 64A at the side edges as shown in FIG.
Such a conventional technology includes a pair of external electrodes 63 and 6.
When a pulsed high-frequency high voltage is applied to 4, an electric field concentrates on the deformed portions 63A and 64A, and a discharge easily occurs between the external electrodes via the rare gas space.

In the prior art, current detecting means 68 for detecting the lamp current of the discharge lamp 60, and the current detecting means 68
And a drive circuit 71 for controlling the on-duty of the switching device 70 of the high frequency generator 60 in accordance with the output of the comparison means 69.
Having. With such a configuration, the on-duty of the switching device 70 is controlled so that the lamp current in FIG. 9 is constant.

According to the prior art, when a crack occurs in one of the pair of external electrodes 63 and 64, the crack extends along the outer surface of the envelope between the original same poles through the crack. Abnormal discharge may occur. If the abnormal discharge continues, there is a possibility that abnormal heat is generated and smoke or fire occurs. In addition, if insulation deterioration occurs between the different electrodes of the external electrodes 63 and 64, abnormal discharge may occur along the outer surface of the envelope between the different electrodes. In this case, if the abnormal discharge continues, smoke or fire may occur. there were.

SUMMARY OF THE INVENTION The present invention is directed to a discharge lamp which can eliminate or reduce anxiety that an abnormal discharge occurs between the same pole of the outer electrode or between different poles, and that the abnormal discharge generates abnormal heat and smoke or ignite. It is an object to provide a lighting device, a discharge lamp lighting device, and a lighting device.

According to a first aspect of the present invention, there is provided a lighting device for a discharge lamp, wherein at least one electrode for generating a discharge in the light-transmitting bulb is provided along an outer surface of the light-transmitting bulb. A high-frequency generator for outputting high-frequency power to energize the discharge lamp, and an electrode provided along the outer surface of the light-transmitting bulb, and transmits the high-frequency power to the discharge lamp. Abnormal protection means for detecting an abnormal discharge different from the discharge generated in the optical bulb and suppressing the output of the high frequency generator.

In the invention described in claim 1 and the following inventions, each configuration and each term are defined as follows unless otherwise specified.

[0008] As the discharge lamp, either one in which all the electrodes for generating a normal discharge are provided along the outer surface of the light-transmitting bulb, or one in which a part thereof is provided along the outer surface of the light-transmitting bulb. It may be. Further, the term "providing along the outer surface of the light-transmitting bulb" means any of those directly attached to the light-transmitting bulb, printing, and the like, and those pasted through an intermediate such as an insulating sheet. The shape and dimensions of the electrodes provided along the outer surface are not limited. Even when a pair of electrodes are provided outside, in addition to the shape shown in FIG. , Rectangular, wavy,
Any shape such as a linear shape may be used. However, it is effective to use a pair of external electrodes having continuous or discontinuous curved portions at opposing portions in that the electric field is easily concentrated.

Further, as the high frequency generator, for example, an inverter, a chopper or the like can be mainly constituted, and in this case, the high frequency generator can be provided with a relatively simple configuration and at a low cost. However, in the present invention, the high frequency generator may have another configuration. Further, the high frequency means a range higher than the commercial frequency, and it is particularly advantageous to set the high frequency to about 20 KHz or higher, which is higher than the audible frequency, in order to reduce the problem of audible noise. A particularly preferable range is 20 to 100 K in consideration of a reduction in switching loss of a semiconductor switching element used in a high frequency generator in many cases.
Hz.

The abnormal protection means firstly detects abnormal discharge of the discharge lamp. As a detection method, the abnormal current is detected by detecting the output current and output voltage of the high frequency generator, light emission due to abnormal discharge, and heat generation. Anything that captures this phenomenon is acceptable. For example, when the output current of the high-frequency generator is used, the current component associated with the abnormal discharge includes a component in a higher harmonic region than that of the normal discharge, so that the harmonic component may be detected. In this case, a current transformer, a resistive voltage dividing circuit, or the like can be used as the current detecting means, and a filter circuit can be used for detecting the harmonic components. Contribute to pricing. When light emission due to abnormal discharge between the electrodes is used, the light at the time of abnormal discharge is generated from a portion facing the external electrode which is normally shielded by the electrode and does not leak to the outside during normal operation. What should I do? In this case, the detection means is slightly complicated, but high detection accuracy can be expected.

Next, the abnormality protection means suppresses the output of the high-frequency generator. As a method of suppression, a switching element such as an inverter or a chopper which constitutes the high-frequency generator suppresses the input voltage itself to the high-frequency generator. The on / off frequency and the on-duty may be changed. However, it is possible to change over a relatively wide range with a small signal,
The one that changes the off frequency and the on duty is the most preferable at the present time. Note that suppressing the output includes stopping the output. In the case of controlling the above-described ON operation of the switching element, the output can be stopped by maintaining the switching element substantially OFF. However, when it is not permissible to turn off the discharge lamp, the output of the high-frequency generator may be reduced so as to reduce the adverse effect of the abnormal discharge and to keep the discharge lamp in a range where it can be maintained. Good.

According to the first aspect of the present invention, the output voltage of the high frequency generator is normally applied between the external electrodes by the discharge lamp,
Discharge is occurring in the translucent bulb.

In the case where the discharge lamp has a pair of electrodes for generating a discharge in the light-transmitting bulb on the outer surface of the bulb, for example, if insulation deterioration occurs between the pair of external electrodes, An abnormal discharge occurs between the external electrodes and along the outer surface of the translucent bulb. Then, the abnormal protection means detects this abnormal discharge. For example, as described above, the abnormal discharge is detected by any one or a combination of the output current and output voltage of the high-frequency generator, light emission due to abnormal discharge, heat generation, and the like. Next, the abnormality protection means suppresses the output of the high frequency generator. Therefore, the abnormal discharge is eliminated or the adverse effect of the abnormal discharge is reduced. How to release the output suppression operation of the abnormality protection means can be arbitrarily designed. For example, the power supply of the entire device is temporarily shut off, the power is turned on after the shutdown, the discharge lamp is replaced, and the reset switch is operated in conjunction with the operation. And so on.

According to a second aspect of the present invention, there is provided a discharge lamp lighting device including a light-transmitting bulb and electrodes for generating a discharge in the bulb, and at least one of the electrodes extends along the outer surface of the light-transmitting bulb. Provided between the discharge lamp, a high-frequency generator that outputs high-frequency power to energize the discharge lamp, and electrodes provided along the outer surface of the light-transmitting bulb, and within the light-transmitting bulb. Abnormality protection means for detecting an abnormal discharge different from the generated discharge and suppressing the output of the high frequency generator.

According to a third aspect of the present invention, there is provided a discharge lamp lighting device including a light-transmitting bulb and electrodes for generating a discharge in the bulb, and at least one of the electrodes is provided along an outer surface of the light-transmitting bulb. In response to the output current in the relatively low-frequency region of the discharge lamp, the high-frequency generator that outputs high-frequency power to energize the discharge lamp, and the high-frequency generator that accompanies the discharge generated in the translucent bulb Then, feedback means for performing feedback control of the high-frequency generator so that the lamp current of the discharge lamp becomes constant, and an electrode formed along the outer surface inside the light-transmitting bulb, and inside the light-transmitting bulb. Abnormal protection means for responding to an output current in a relatively high frequency region of the high frequency generator accompanying an abnormal discharge different from the generated discharge, and suppressing an output of the high frequency generator. .

According to the third aspect of the present invention, the feedback means and the abnormality protection means may each have their own current detecting means, but they may share the current detecting means. When the current detection means is provided separately,
It has the advantage of being able to independently set constants, simplifying electrical insulation and simplifying circuit design, and has the advantage of reducing the number of parts and reducing size and cost when sharing current detection means.

In the feedback means and the abnormality protection means, a filter is usually used to detect an output current in a relatively low frequency region and a relatively high frequency region. Such a filter is a target in advance. The constant is set so that a signal in the frequency band of the normal discharge current of the discharge lamp or the frequency band of the abnormal discharge current can be extracted.

Further, the feedback means and the abnormality protection means respectively control the high frequency generator in accordance with the detection signal. When the abnormality protection means suppresses the output of the high frequency apparatus, this control is performed by the feedback control of the feedback means. Takes precedence over As means for giving priority to this, it is conceivable to deactivate the feedback means by a control signal of the abnormality protection means or to change a reference value to be compared in the feedback means. The realization of such means can be achieved relatively simply by using ICs.

According to a third aspect of the present invention, when the discharge lamp is normally lit, the high frequency generator is controlled by the feedback means so that the lamp current of the discharge lamp becomes a predetermined value.

Further, for example, when abnormal discharge occurs between different poles of the external electrode of the discharge lamp and on the outer surface of the bulb, the output current of the high frequency generator includes a current in a relatively high frequency region accompanying the abnormal discharge. Become like Therefore, the abnormality protection means detects the output current in the relatively high frequency region and suppresses the output of the high frequency generator.

According to a fourth aspect of the present invention, in addition to the second or third aspect of the present invention, the discharge lamp lighting device is configured to disable the output suppression of the high frequency generator by the abnormal protection means for a predetermined period when the discharge lamp is started. It is characterized by having control means.

According to the fourth aspect of the present invention, when the discharge lamp is started, an unstable lighting state may be exhibited as a transient state until stable lighting is performed in normal times. Disable output suppression.
Therefore, it is possible to prevent the discharge lamp from being unable to shift to normal lighting in response to the unstable lighting state at the time of starting.

According to a fifth aspect of the present invention, there is provided a lighting device comprising: a device main body to which a discharge lamp is attached; and a discharge lamp lighting device according to the first aspect for lighting the discharge lamp.

Next, one embodiment of the present invention will be described.

FIG. 1 is a circuit diagram showing an embodiment of a lighting device for a discharge lamp or a lighting device for a discharge lamp according to the present invention. Reference numeral 1 denotes a discharge lamp provided with a pair of electrodes 3 and 4 on the outer surface of a translucent bulb 2. An embodiment of such a discharge lamp 1 can be the one shown in FIGS. 7 and 8 or JP-A-11-307292. The high-frequency generator 5 for energizing and lighting the discharge lamp 1 includes an output transformer 6, a switching element 7, and a switching element 7.
The oscillation control device 8 is mainly constituted by a single-type inverter. The oscillation control device 8 controls on / off of the switching element 7 at a frequency of several tens KHz to several hundred KHz, for example, 70 KHz. By such an on / off control, the electric power accumulated in the output transformer 6 during the on period of the switching element 7 is supplied to the discharge lamp 1 when the switching element 7 is turned off. Reference numeral 9 denotes a resistor for detecting a current flowing through the switching element 7, and reference numeral 10 denotes a signal for controlling the on / off frequency and the on-duty of the switching element 7 or both of them in accordance with the detected current to the oscillation control device 8. This is a comparison device. For example, when the current value flowing through the switching element 7 is larger than a predetermined value, the comparison device 10 performs control such that the current value is equal to or smaller than the predetermined value.

The lamp current of the discharge lamp 1 is determined by the current detecting resistor 11
Is detected by The abnormal protection means 12 detects abnormal discharge of the discharge lamp 1 by using the detection of the current detection resistor 11. The abnormality protection unit 12 of the present embodiment has a high-pass filter unit 13 on the input side, a transistor 14 whose on / off is controlled by the output of the high-pass filter unit 13, and a transistor 15 whose on / off is controlled by the transistor 14. .
Further, abnormal signal output means 16 whose operation is controlled by turning on and off the transistor 15, display driving means 17 responsive to the abnormal signal output means 16, and display means 1
Eight.

When the detection signal of the current detecting means 11 includes a signal in a relatively high frequency region described later, the high-pass filter section 13 outputs a signal, and the transistor 14 is turned on. I do. When the transistor 14 is turned on, the transistor 15 is turned on and the abnormal signal output means 16 is operated, and outputs a signal for suppressing the output of the high frequency generator to the oscillation control device 8. On the other hand, a signal for operating the display means 18 is output to the display drive means 17. When the detection signal of the current detection means 11 does not include the signal in the relatively high frequency region, the high-pass filter unit 13 does not output the signal, and thus does not output the output suppression signal and the display operation signal.

In the present embodiment, the detection signal of the current detecting means 11 is also used for controlling the light output of the discharge lamp 1 to be constant. That is, the feedback means 19 is provided. The feedback unit 19 includes a rectifying unit 20 that rectifies and smoothes the detection signal, and a comparing unit 21 that compares an output of the rectifying unit 20 with a reference signal and outputs a feedback signal to the oscillation control device.

Next, the operation of the present embodiment will be described. When the discharge lamp 1 is in a normal state in which a normal discharge is generated in the translucent bulb 2, the abnormality protection means 12 does not output the output suppression signal and the display operation signal. On the other hand, the switching element 7
The resistor 9 and the comparison device 10 that detect the current flowing through
The current flowing through the switching element 7 is monitored, and the necessary control as described above is performed. Also, feedback means 19
In this case, a signal is output to the oscillation control device 8 so that the light output of the discharge lamp 1 is constant, for example, the on-duty of the switching element 7 is controlled.

Next, a crack is generated in one or both of the electrodes 3 and 4 of the discharge lamp 1, and an abnormal discharge is generated between the electrodes having the same polarity through the crack, or a different polarity is generated. When an abnormal discharge occurs between the electrodes 3 and 4, the detection signal of the current detection unit 11 includes a signal in a relatively high frequency range. Although the details of the fact that a high-frequency current flows relatively to the abnormal discharge in the abnormal discharge are not clear, according to experiments performed by the present inventors, a high-frequency current always flows during the abnormal discharge. became. FIG. 2 shows an example of a current waveform at the time of normal discharge (solid line) and an example of a current waveform at the time of abnormal discharge (dashed line).

Therefore, the abnormality protection means 12 responds to the high frequency component of the current detection signal and outputs the output suppression signal and the display operation signal as described above.

FIG. 3 is a schematic view showing an example of the illumination device of the present invention. Reference numeral 30 denotes an apparatus main body, which is, for example, an OA apparatus such as a facsimile, an image scanner, or a copying machine, and a display device such as an evacuation guide light. An illumination unit 31 including a discharge lamp and a discharge lamp lighting device is housed in the device main body 30. The display means 32 as described with reference to FIG. 1 is provided on the outer surface of the device main body 30. Thus, the user can easily know the abnormal discharge of the discharge lamp and the replacement time of the discharge lamp.

FIG. 4 is a circuit diagram showing another embodiment of the discharge lamp lighting device or the discharge lamp lighting device of the present invention. FIG.
The same or corresponding parts are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, the abnormality protection means 40 has a low-pass filter section 41 on the input side, and the output of the low-pass filter section 41 controls the on / off of the transistor 4.
2. It has a transistor 43 whose on / off is controlled by this transistor 42, and a transistor 44 whose on / off is controlled by this transistor 43.

In this embodiment, a start control means 45 for disabling the suppression of the output of the high frequency generator by the abnormality protection means 40 at the time of start is provided. The start control means 45 includes a timer section 46 composed of an integrating circuit and a timer section 4.
Transistor 4 whose on / off is controlled by the output of 6
7, 48. The collector of the transistor 48 is connected to the base of the transistor 43 of the abnormality protection means 40 via the diode 49. That is, the base and the emitter of the transistor 43 can be substantially short-circuited by the transistor 48.

In this embodiment, at the time of starting, the transistor 47 is off and the transistor 48 is on until the timer 46 reaches a predetermined value, so that the abnormality protection means 40 is kept off. Therefore, even when a high-frequency current similar to that during abnormal discharge flows as a transient state when the discharge lamp 1 is started, the abnormal protection means 40 does not operate. When the output of the timer section 46 reaches a predetermined value, the transistor 47 is turned on and the transistor 48 is turned off, so that the abnormality protection means 40 can respond to the abnormal signal at the time of abnormal discharge.

FIG. 5 is a sectional view showing another example of the discharge lamp. The discharge lamp 50 according to the present embodiment has one electrode 52 provided inside a light-transmitting bulb 51 and the other electrode 53 provided on the outer surface of the light-transmitting bulb 51. A discharge is generated inside the light bulb 51. However, when a crack occurs in the electrode 53 on the outer surface and a potential difference occurs through the crack, an abnormal discharge may occur through the crack. Therefore, the present invention is also effective for such a discharge lamp 50.

According to the first to third aspects of the present invention, even if the discharge lamp generates an abnormal discharge along the outer surface electrode, the abnormal discharge is detected and the output of the high frequency generator is suppressed. Problems such as smoke and ignition caused by continuing can be eliminated or reduced.

According to the fourth aspect of the present invention, the output suppression of the high-frequency generator is disabled when the discharge lamp is started, so that it is not affected by unstable lighting at the start.

The third aspect of the present invention provides the first to fourth aspects.
A lighting device having the same effects as the effects of the described invention can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a discharge lamp lighting device or a discharge lamp lighting device of the present invention.

FIG. 2 is a waveform diagram showing an example of a current waveform during normal discharge (solid line) and an example of a current waveform during abnormal discharge (dashed line).

FIG. 3 is a schematic view showing an embodiment of the lighting device of the present invention.

FIG. 4 is a circuit diagram showing another embodiment of the discharge lamp lighting device or the discharge lamp lighting device of the present invention.

FIG. 5 is a sectional view showing an example of a discharge lamp applied to the present invention.

FIG. 6 is a circuit diagram showing an example of a conventional discharge lamp lighting device.

FIG. 7 is a sectional view showing an example of a conventional discharge lamp.

FIG. 8 is a development view of a light-transmitting bulb and an external electrode.

FIG. 9 is a waveform chart showing a lamp current of the discharge lamp.

[Explanation of symbols]

1,50 ... discharge lamp, 5 ... high frequency generator, 12,40 ...
Abnormality protection means, 20 feedback means, 45 start control means.

Claims (5)

[Claims] A lighting device for a discharge lamp for high frequency lighting of a discharge lamp in which at least one electrode for generating a discharge in the light-transmitting bulb is provided along the outer surface of the light-transmitting bulb. A high-frequency generator for outputting high-frequency power to energize the discharge lamp; and a discharge generated between the electrodes provided along the outer surface of the light-transmitting bulb and different from the discharge generated in the light-transmitting bulb. A lighting device for a discharge lamp, comprising: abnormal protection means for detecting an abnormal discharge and suppressing the output of the high frequency generator. A discharge lamp having a translucent bulb and electrodes for generating a discharge in the bulb, at least one of the electrodes being provided along an outer surface of the translucent bulb;
A high-frequency generator that outputs high-frequency power to energize the discharge lamp; an abnormality that occurs between electrodes provided along the outer surface of the light-transmitting bulb and that is different from the discharge that occurs in the light-transmitting bulb A discharge lamp lighting device, comprising: an abnormality protection unit that detects discharge and suppresses output of the high frequency generator. 3. A light-emitting bulb having a light-transmitting bulb and electrodes for generating a discharge in the bulb, at least one of the electrodes being provided along an outer surface of the light-transmitting bulb; An output-variable high-frequency generator for outputting and energizing the discharge lamp; responsive to an output current in a relatively low-frequency region of the high-frequency generator accompanying the discharge generated in the light-transmitting bulb;
Feedback means for performing feedback control of the high frequency generator so that the lamp current of the discharge lamp is constant; generated between electrodes provided along the outer surface of the translucent bulb; and
Abnormal protection means for responding to an output current in a relatively high frequency region of the high frequency generator associated with an abnormal discharge different from the discharge generated in the translucent bulb and suppressing the output of the high frequency generator. A discharge lamp lighting device. 4. A starting control means for disabling output suppression of the high frequency generator by the abnormal protection means for a predetermined period at the time of starting the discharge lamp. A discharge lamp lighting device according to one of the preceding claims. 5. A lighting device comprising: a device main body to which a discharge lamp is attached; and the lighting device for a discharge lamp according to claim 1, which lights the discharge lamp.