JP2000306689A - Abnormality detecting method for discharge lamp, its device, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost increase by eliminating a filament current detecting circuit and detect abnormality in a discharge lamp, by including a current detecting process for detecting current in both directions of the discharge lamp and a stopping process of an invertor operation when the detected value in the current detecting process is out of a predetermined range. SOLUTION: A resistor R1 is connected to a secondary winding of a current transformer through a current detecting means CT1, alternating voltage corresponding to current value of a discharge lamp 8 occurs across the resistor R1. The peak voltage of this alternating voltage in each direction is detected in combination of a diode D1 and a capacitor C3, and a diode D2 and a capacitor C4. The peak voltage value in each direction is fed into a comparing circuit 5. When one of two peak voltage values is out of a predetermined range in the comparing circuit 5, an invertor operation of a driver 3 is stopped through an abnormality detecting circuit 4. The current detecting means CT1 detects a state that tube current directs one way and no discharge lamp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting an abnormality of a discharge lamp such as a fluorescent lamp and a storage medium storing a control program for controlling the apparatus for detecting an abnormality of the discharge lamp. Related to

[0002]

2. Description of the Related Art Normally, in an inverter of a discharge lamp such as a fluorescent lamp, an inductive load such as a choke coil is used as a ballast. However, in order to reduce costs and save space, a ballast has a capacity such as a capacitor. Sexual load may be used.

FIG. 4 is a block diagram showing the configuration of a conventional discharge lamp abnormality detecting device. In FIG.
C input voltage, 2 is an inverter frequency setting means, 3 is a driver, 4 is an abnormality detection circuit, 5 is a comparison circuit, 6 is a driver, 7 is a dimming frequency setting means, 8 is a discharge lamp such as a fluorescent lamp, and 9 is a light amount. A sensor 10 is a dimming control circuit, and includes an operational amplifier (OP-Amp1) 10a and a variable resistor (VR) 10
b. 11 is an abnormality display means, 12 is a comparator (comp2), T1 is an inverter transformer, N
P1 is the primary winding of the inverter transformer T1, NS1,
NS2 is a secondary winding of the inverter transformer T1, Tr1
Is a primary-side switching transistor, Tr2 is a secondary-side dimming transistor, D1 is a diode, DB1 is a bridge, CT1 is current detecting means such as a current lance, R1 is a resistor, L2 is a coil, C1, C2, and C3 are It is a capacitor.

[0004]

However, in the above-mentioned prior art, since a capacitive load is used for the ballast, there are the following problems.

That is, when the discharge of the discharge lamp 8 is normal,
The current waveform of the discharge lamp 8 is as shown in FIG. 5 (a), and the base voltage of the dimming transistor Tr2 is as shown in FIG. 5 (b). Then, the phenomenon in which the tube current flows only in one direction "Ip2 <<Ip1" in FIG. 5C may occur (see FIG. 5C).

At this time, in an inverter using a capacitive load as a ballast, only one side of the ballast capacitor continues to be charged, no discharge is performed, and in some cases, the capacitor is destroyed.

Further, when the phenomenon that the tube current flows only in one direction as described above occurs, when the dimming control of the discharge lamp 8 is performed using a dimming sensor or the like, the dimming duty is widened. And the current value is corrected,
It is not possible to distinguish between an abnormal case and a normal case [FIGS. 5 (d) and 5 (e)].
reference".

Further, even when the value of the entire tube current, for example, the effective value of the current of the discharge lamp 8 is detected, it is impossible to distinguish between an abnormal time and a normal time for the same reason as described above.

When only the current in one direction of the discharge lamp 8 is detected (for example, the peak current value in one direction is detected), an abnormality in the detected direction (current does not flow) can be detected. However, it cannot detect anomalies in the opposite direction.

[0010] It is impossible to specify or foresee in which direction current will flow when the lamp tube of the discharge lamp 8 reaches the end of its life at the initial stage of durability. And the direction in which current can be detected cannot be matched in advance.

Usually, in order to detect a state in which the tube current flows in only one direction, there is a method of detecting not the tube current but the filament current flowing through the filament.
In this method, a separate filament current detection circuit is required, so that the number of parts increases and the cost increases.

The present invention has been made in view of the above-mentioned problems of the prior art, and a first object of the present invention is to eliminate the need for a separate filament current detection circuit. Further, it is an object of the present invention to provide a method and apparatus for detecting an abnormality of a discharge lamp that can reliably detect an abnormal state of the discharge lamp without increasing the cost.

A second object of the present invention is to provide a storage medium storing a control program capable of smoothly controlling the above-described discharge lamp abnormality detecting device of the present invention. Things.

[0014]

According to a first aspect of the present invention, there is provided a method for detecting an abnormality in a discharge lamp.
A current detecting step of detecting a current value in both directions of the discharge lamp; and a stopping step of stopping the inverter operation when the detected value of the current detecting step is a value outside a predetermined range. .

According to a second aspect of the present invention, there is provided a method for detecting an abnormality in a discharge lamp according to the first aspect of the present invention, wherein the detected value is a value of the discharge lamp. It is characterized by peak values of current in both directions.

According to a third aspect of the present invention, there is provided a method for detecting an abnormality in a discharge lamp according to the first aspect of the present invention, wherein the detected value is a value of the discharge lamp. It is characterized by the average value of the absolute values of the currents in both directions.

According to a fourth aspect of the present invention, there is provided a discharge lamp abnormality detecting method for detecting the presence or absence of the discharge lamp. A detecting step of stopping the inverter operation also when the lamp detecting step detects that the discharge lamp is not present.

According to another aspect of the present invention, there is provided a method for detecting an abnormality in a discharge lamp.
3. The method for detecting an abnormality of a discharge lamp according to 3 or 4,
The discharge lamp is a fluorescent lamp.

According to another aspect of the present invention, there is provided a discharge lamp abnormality detecting apparatus for detecting a current value in both directions of a discharge lamp, and a detecting value of the current detecting means. And stopping means for stopping the operation of the inverter when the value is outside the predetermined range.

According to a seventh aspect of the present invention, there is provided a discharge lamp abnormality detecting apparatus according to the sixth aspect, wherein the detected value is a value of the discharge lamp. It is characterized by peak values of current in both directions.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 8 is the discharge lamp abnormality detection device according to claim 6, wherein the detected value is the discharge lamp abnormality. It is characterized by the average value of the absolute values of the currents in both directions.

According to a ninth aspect of the present invention, there is provided a discharge lamp abnormality detecting apparatus for detecting the presence or absence of the discharge lamp. A detecting means is provided, and the stopping means stops the inverter operation even when the lamp detecting means detects that there is no discharge lamp.

According to a tenth aspect of the present invention, there is provided a discharge lamp abnormality detecting apparatus according to the tenth aspect.
10. The abnormality detecting device for a discharge lamp according to any one of items 8 to 9, wherein the discharge lamp is a fluorescent lamp.

In order to achieve the first object, a method for detecting abnormality of a discharge lamp according to claim 11 includes a current detection step of detecting a current value in both directions of the discharge lamp, and a detection value of the current detection step. Determining that the discharge lamp is in an abnormal state when the discharge lamp is outside a predetermined range, and stopping the inverter operation when the discharge lamp is determined to be in an abnormal state by the determination step. And stopping the current supply to the discharge lamp.

According to a twelfth aspect of the present invention, there is provided a method for detecting an abnormality in a discharge lamp.
2. The abnormality detection method for a discharge lamp according to claim 1, wherein the detected value is a peak value of a current in both directions of the discharge lamp.

In order to achieve the first object, a method for detecting an abnormality in a discharge lamp according to claim 13 is provided.
2. The abnormality detection method for a discharge lamp according to claim 1, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp.

[0027] In order to achieve the first object, a method for detecting an abnormality of a discharge lamp according to claim 14 is provided.
2. The method for detecting an abnormality of a discharge lamp according to claim 1, further comprising a lamp detection step of detecting the presence or absence of the discharge lamp, wherein the stopping step includes the step of detecting the absence of the discharge lamp by the lamp detection step. The operation is stopped.

In order to achieve the first object, a method for detecting an abnormality in a discharge lamp according to claim 15 is provided by claim 1.
15. The abnormality detection method for a discharge lamp according to any one of 1 to 13 or 14, wherein the discharge lamp is a fluorescent lamp.

According to another aspect of the present invention, there is provided a discharge lamp abnormality detecting apparatus for detecting a current value in both directions of a discharge lamp, and a detecting value of the current detecting means. Determining that the discharge lamp is in an abnormal state when the value is out of a predetermined range; and stopping the inverter operation when the determination unit determines that the discharge lamp is in an abnormal state. And stopping means for stopping current supply to the discharge lamp.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 17 is provided.
7. The abnormality detection device for a discharge lamp according to claim 6, wherein the detected value is a peak value of a current in both directions of the discharge lamp.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 18 is provided.
7. The abnormality detecting device for a discharge lamp according to claim 6, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 19 is provided.
7. The abnormality detecting device for a discharge lamp according to claim 6, further comprising: lamp detecting means for detecting the presence / absence of the discharge lamp, wherein the stopping means includes means for detecting the absence of the discharge lamp by the lamp detecting means. The operation is stopped.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 20 is provided.
20. The abnormality detecting device for a discharge lamp according to any one of 6 to 18 or 19, wherein the discharge lamp is a fluorescent lamp.

According to another aspect of the present invention, there is provided a discharge lamp abnormality detecting device, comprising: an inverter transformer; a switching transistor on a primary side of the inverter transformer; and a secondary side of the inverter transformer. Dimming transistor, a capacitive ballast connected in series between the discharge lamp and the inverter transformer,
Current detecting means for detecting a current value in both directions of the discharge lamp; andstop means for stopping the inverter operation when the detected value of the current detecting means is a value outside a predetermined range. I do.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 22 is provided.
2. The abnormality detecting device for a discharge lamp according to claim 1, wherein the current detecting means is connected in series with the capacitive ballast and the discharge lamp.

In order to achieve the first object, an abnormality detecting device for a discharge lamp according to claim 23 is provided.
2. The discharge lamp abnormality detection device according to claim 1, wherein the current detection means is connected in series with the switching transistor.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 24 is provided.
2. The discharge lamp abnormality detecting device according to claim 1, wherein the current detecting means is connected in series with the dimming transistor.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 25 is provided.
2. The discharge lamp abnormality detection device according to claim 1, wherein the detected value is a peak value of a current in both directions of the discharge lamp.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 26 is provided.
2. The abnormality detecting device for a discharge lamp according to claim 1, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 27 is provided.
2. The abnormality detection device for a discharge lamp according to claim 1, further comprising: a lamp detection unit configured to detect the presence or absence of the discharge lamp, wherein the stop unit performs the inverter operation even when the lamp detection unit detects that there is no discharge lamp. It is characterized by stopping.

In order to achieve the first object, a discharge lamp abnormality detecting device according to claim 28 is provided.
28. The discharge lamp abnormality detection device according to any one of 1 to 26 or 27, wherein the discharge lamp is a fluorescent lamp.

In order to achieve the second object, a storage medium according to claim 29 is a storage medium storing a control program for controlling a discharge lamp abnormality detecting device for detecting an abnormality of a discharge lamp. The control program may further include a control module configured to detect a current value in both directions of the discharge lamp, and to control to stop the inverter operation when the detected value is a value outside a predetermined range. It is characterized by having.

In order to achieve the second object, the storage medium according to claim 30 is the storage medium according to claim 29, wherein the detected value is a peak value of a current in both directions of the discharge lamp. It is characterized by the following.

In order to achieve the second object, the storage medium according to claim 31 is the storage medium according to claim 29, wherein the detected value is an average of absolute values of currents in both directions of the discharge lamp. Value.

In order to achieve the second object, a storage medium according to claim 32 is the storage medium according to claim 29, wherein the control program detects that the discharge lamp is not present. A control module for controlling to stop the inverter operation.

Further, in order to achieve the second object, the storage medium according to claim 33 is characterized in that:
3. The storage medium according to claim 2, wherein the discharge lamp is a fluorescent lamp.

In order to achieve the second object, a storage medium according to claim 34 is a storage medium storing a control program for controlling a discharge lamp abnormality detection device for detecting an abnormality of a discharge lamp. The control program detects current values in both directions of the discharge lamp, and determines that the discharge lamp is in an abnormal state when the detected value is out of a predetermined range. A control module for stopping the operation to control the supply of current to the discharge lamp.

In order to achieve the second object, the storage medium according to claim 35 is the storage medium according to claim 34, wherein the detected value is a peak value of a current in both directions of the discharge lamp. It is characterized by the following.

In order to achieve the second object, the storage medium according to claim 36 is the storage medium according to claim 34, wherein the detected value is an average of absolute values of currents in both directions of the discharge lamp. Value.

Further, in order to achieve the second object, the storage medium according to claim 37 is provided with a storage medium according to claim 34, 35, or 3.
7. The storage medium according to claim 6, wherein the discharge lamp is a fluorescent lamp.

[0051]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the first embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS.

FIG. 1 is a block diagram showing a configuration of a discharge lamp abnormality detecting apparatus according to a first embodiment of the present invention. In FIG. 1, the same parts as those in FIG. The code is attached.

FIG. 1 differs from FIG. 4 in that a diode D2 and a capacitor C4 are added to the configuration of FIG.

In FIG. 1, 1 is a DC input voltage, 2 is an inverter frequency setting means, 3 is a driver, 4 is an abnormality detection circuit, 5 is a comparison circuit, 6 is a driver, 7 is a dimming frequency setting means, and 8 is fluorescent light. A discharge lamp such as a lamp, 9 is a light amount sensor, 10 is a dimming control circuit, and an operational amplifier (OP-Amp
1) It has a 10a and a variable resistor (VR) 10b.
11 is an abnormality display means, 12 is a comparator (comp)
2), T1 is an inverter transformer, NP1 is a primary winding of the inverter transformer T1, NS1 and NS2 are secondary windings of the inverter transformer T1, Tr1 is a primary switching transistor, and Tr2 is a secondary dimming transistor. , D1, D2 are diodes, DB1 is a bridge, CT
1 is a current detecting means such as a current lance, R1 is a resistor, L2 is a coil, and C1, C2, C3 and C4 are capacitors.

The DC input voltage 1 is applied to the inverter transformer T
1 primary winding NP1. The DC input voltage 1 is turned on / off by the primary-side switching transistor Tr1, and is transmitted to the secondary side of the inverter transformer T1 as an alternating current. The switching transistor Tr1 on the primary side is driven by the driver 3. The driver 3 is driven by the inverter frequency setting means 2 at a constant frequency, for example. The abnormality detection circuit 4 detects an abnormality of the discharge lamp 8, and stops driving of the driver 3 when the abnormality of the discharge lamp 8 is detected. The abnormality display means 11 is used in the state where the tube current only flows in one direction at the end of the life of the discharge lamp 8 or the state where the discharge lamp is not mounted (discharge lamp absence detection), which is the main object of the present invention. Information indicating this is displayed.

The secondary winding NS of the inverter transformer T1
Numeral 1 supplies a voltage necessary for normal lighting of the discharge lamp 8, and the lighting current of the discharge lamp 8 in the normal lighting state is determined by the voltage value of the secondary winding NS1 and the impedance value of the capacitor C2. The value is determined. Inverter transformer T1
The secondary winding NS2 supplies a necessary voltage when the discharge lamp 8 is started, and includes a voltage value of the secondary winding NS2,
The preliminary lighting current value of the discharge lamp 8 is determined by the value of the impedance of the coil L2.

Here, the preliminary lighting current refers to the discharge lamp 8
Means the current flowing during the time from the start of operation to the transition to the normal lighting state. Note that, to be precise, the preliminary lighting current value of the discharge lamp 8 is determined by “the voltage value of NS2” + “the voltage value of NS1” and “the value of the impedance of L2” + “the value of the impedance of C2”. “NS1 voltage value <<
NS2 voltage value ”,“ C2 impedance value << L
Since the value of the impedance is “2,” it is as described above.

An AC voltage is output to the secondary windings NS1 and NS2.

The light quantity sensor 9 inputs a voltage corresponding to the light quantity to the dimming control circuit 10. Control is performed by the dimming control circuit 10 and a subsequent circuit so that the input value and a predetermined constant value (the value of the variable resistor 10b: VR) become constant. The bridge DB1 rectifies an alternating current flowing through the discharge lamp 8 into a direct current. The rectification is controlled on / off by the secondary-side dimming transistor Tr2 (for example, 2.7 KH
z) Then, by changing the duty ratio, the dimming control is performed so that the output value of the light amount sensor 9, that is, the light amount of the discharge lamp 8 becomes constant.

The base of the light control transistor Tr 2 is driven via the driver 6 at a frequency and a duty ratio determined by the output of the light control frequency setting means 7 and the output of the light control circuit 10.

In the current detecting means CT1, a resistor R1 is connected to the secondary winding of the current lance, and an AC voltage corresponding to the current value of the discharge lamp 8 is generated at both ends of the resistor R1. With this combination of the AC voltage and the diode D1 and the capacitor C3, and the diode D2 and the capacitor C4, the peak voltage value is detected separately in both directions. The peak voltage value in each direction is input to the comparison circuit 5. This comparison circuit 5
When one of the two peak voltage values is out of the predetermined range, the inverter operation of the driver 3 is stopped via the abnormality detection circuit 4. Further, information indicating that this abnormality has occurred is displayed on the abnormality display means 11.

The current detecting means CT1 has a function of detecting a state in which a discharge lamp is not mounted (detection of no discharge lamp), in addition to the above-described function. This is the case when the discharge lamp is forgotten or the discharge lamp is detached from the base. For example, due to the restriction of the load on the control microcomputer (microcomputer) of the entire copying machine, detection is performed not only in both directions but only in one direction. Good. If a state in which the discharge lamp is not mounted (discharge lamp absence detection) is detected, information indicating that fact is displayed on the abnormality display means 11.

In this embodiment, the current detecting means CT1 is
Both the detection of the state where the tube current flows only in one direction and the detection of the absence of the discharge lamp are performed.

In the present embodiment, the ballast at the position of the capacitor C2 is capacitive, and the ballast at the position of the coil L2 is inductive. Even if the ballasts are all capacitive, they do not depart from the gist of the present invention.

FIG. 5 (a) shows a lamp current waveform when the discharge of the discharge lamp 8 is normal, as shown in FIG. 5 (b).
When the base voltage of the light control transistor Tr2 is high, a lamp current flows. The duty ratio in FIG. 5B is determined by the dimming feedback control of the dimming frequency setting unit 7, the light amount sensor 9, the dimming control circuit 10, and the operational amplifier 12.

FIG. 5C shows a lamp current waveform when the discharge of the discharge lamp 8 is abnormal, and shows the peak value (I
p2) becomes extremely smaller than the peak value (Ip1) of the other current. At this time, if the dimming control is performed, the lamp current waveform of the discharge lamp 8 is as shown in FIG. 5D, and the base voltage of the dimming transistor Tr2 is as shown in FIG.

As shown in FIGS. 5B to 5E, the dimming duty ratio is widened to correct the effective value of the lamp current, that is, the light amount of the discharge lamp 8.

In the discharge lamp abnormality detecting apparatus according to the present embodiment, the functions of the above-described embodiment are realized by a computer reading and executing a control program stored in a storage medium. However, the present invention is not limited to this, and performs a part or all of actual processing such as an OS (Operating System) running on a computer based on the instruction of the control program, and performs the processing described above. Needless to say, a case where the function of the present embodiment is realized is also included.

The storage medium for storing the control program is, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM (Co-ROM).
mpact Disk Read Only Memo
ry), CD-R (Compact Disk Rec)
order, a magnetic tape, a nonvolatile memory card, a ROM chip, or the like.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIG.

In the present embodiment, the current is detected by the dimming transistor Tr2 on the secondary side, and it is determined whether or not the discharge of the discharge lamp 8 is abnormal based on the average value of the absolute values of the currents in both directions. It was done.

FIG. 2 is a block diagram showing the configuration of a discharge lamp abnormality detecting apparatus according to a second embodiment of the present invention. In FIG. 2, the same parts as those in FIG. The code is attached.

FIG. 2 differs from FIG. 4 in that a capacitor C21 and resistors R21 and R22 are added to the configuration of FIG.

FIG. 5F shows the waveform of the current flowing through the light control transistor Tr2 when the discharge of the discharge lamp 8 is abnormal and the light control is performed.

In FIG. 2, since the current is converted into a voltage by the resistor R21 and smoothed by a filter including the resistor R22 and the capacitor C21, for example, the absolute value of the normal current value in the plus direction and the absolute value of the minus The average value (Ip3) of the abnormal current value and the absolute value is input to the comparison circuit 5 (see FIG. 5F).

Here, as in the first embodiment described above, even if the peak value of the current is detected, it is not possible to distinguish between the normal state and the abnormal state. Is determined to be abnormal.

According to the present embodiment, it is determined whether or not the discharge of the discharge lamp 8 is abnormal based on the average value of the absolute values of the currents in both directions. Therefore, the cost is lower than that of the first embodiment. There is an advantage that cheap parts can be used.

The other configuration and operation of the discharge lamp abnormality detecting device according to the present embodiment are the same as those of the first embodiment described above, and therefore description thereof is omitted.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
The embodiment will be described with reference to FIG.

In the present embodiment, the current is detected by the switching transistor Tr1 on the primary side, and it is determined whether or not the discharge of the discharge lamp 8 is abnormal based on the average value of the absolute values of the currents in both directions. It is.

FIG. 3 is a block diagram showing a configuration of a discharge lamp abnormality detecting apparatus according to a third embodiment of the present invention. In FIG. 3, the same parts as those in FIG. The code is attached.

FIG. 3 differs from FIG. 4 in that a capacitor C31 and resistors R31 and R32 are added to the configuration of FIG.

FIG. 5F shows the waveform of the current flowing through the light control transistor Tr2 when the discharge of the discharge lamp 8 is abnormal and the light control is performed.

In FIG. 3, since the current is converted into a voltage by the resistor R31 and smoothed by a filter including the resistor R32 and the capacitor C31, for example, the absolute value of the normal current value in the plus direction and the absolute value of the minus The average value (Ip3) of the abnormal current value and the absolute value is input to the comparison circuit 5 (see FIG. 5F).

Here, as in the first embodiment described above, even if the peak value of the current is detected, it is not possible to distinguish between a normal state and an abnormal state. Is determined to be abnormal.

According to the present embodiment, it is determined whether or not the discharge of the discharge lamp 8 is abnormal based on the average value of the absolute values of the currents in both directions. Therefore, the cost is lower than that of the first embodiment. There is an advantage that inexpensive components can be used and the input current protection circuit of the entire inverter can be shared.

The other structure and operation of the discharge lamp abnormality detecting device according to the present embodiment are the same as those of the first embodiment described above, and the description thereof is omitted.

[0089]

As described above in detail, according to the method and apparatus for detecting an abnormality in a discharge lamp of the present invention, the current value in both directions of the discharge lamp is detected, and the detected value is set to a value outside a predetermined range. If there is, the discharge lamp is determined to be abnormal, the inverter operation is stopped, and the current supply to the discharge lamp is stopped. Thus, an effect that the abnormality of the discharge lamp can be reliably detected is achieved.

Further, according to the storage medium of the present invention, it is possible to smoothly control the discharge lamp abnormality detecting device of the present invention described above.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a discharge lamp abnormality detection device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a discharge lamp abnormality detection device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a discharge lamp abnormality detection device according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional discharge lamp abnormality detection device.

FIG. 5 is a diagram showing a lamp current waveform, a base voltage of a dimming transistor, and a current waveform of a switching transistor in the present invention and a conventional discharge lamp abnormality detection device.

[Explanation of symbols]

 Reference Signs List 1 DC input voltage 2 Inverter frequency setting means 3 Driver 4 Abnormality detection circuit 5 Comparison circuit 6 Driver 7 Dimming frequency setting means 8 Discharge lamp 9 Light intensity sensor 10 Dimming control circuit 10a Operational amplifier (OP-Amp1) 10b Variable resistor (VR) DESCRIPTION OF SYMBOLS 11 Abnormal display means 12 Comparator (comp2) C1 capacitor C2 capacitor C3 capacitor C4 capacitor C21 capacitor C31 capacitor CT1 Current detecting means D1 Diode D2 Diode DB1 Bridge L2 Coil NP1 Primary winding NS1 Secondary winding NS2 Secondary winding T1 converter transformer Tr1 switching transistor Tr2 dimming transistor R1 resistor R21 resistor R22 resistor R31 resistor R32 resistor

Claims (37)

[Claims] 1. A current detecting step for detecting a current value in both directions of a discharge lamp, and a stopping step for stopping an inverter operation when a detected value of the current detecting step is out of a predetermined range. A method for detecting an abnormality of a discharge lamp. 2. The method according to claim 1, wherein the detected value is a peak value of a current in both directions of the discharge lamp. 3. The method according to claim 1, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp. 4. A lamp detecting step for detecting the presence or absence of the discharge lamp, wherein the stopping step includes stopping the inverter operation even when the absence of the discharge lamp is detected by the lamp detecting step. Claim 1.
The method for detecting an abnormality of the discharge lamp described in the above. 5. The method according to claim 1, wherein the discharge lamp is a fluorescent lamp. 6. A current detecting means for detecting a current value in both directions of the discharge lamp, and a stopping means for stopping an inverter operation when a detected value of the current detecting means is out of a predetermined range. An abnormality detection device for a discharge lamp. 7. The discharge lamp abnormality detecting device according to claim 6, wherein the detected value is a peak value of a current in both directions of the discharge lamp. 8. The discharge lamp abnormality detecting device according to claim 6, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp. 9. A lamp detecting means for detecting the presence / absence of the discharge lamp, wherein the stopping means stops the inverter operation even when the lamp detecting means detects the absence of the discharge lamp. Claim 6
An abnormality detection device for a discharge lamp as described in the above. 10. The discharge lamp abnormality detecting device according to claim 6, wherein the discharge lamp is a fluorescent lamp. 11. A current detecting step for detecting a current value in both directions of the discharge lamp, and determining that the discharge lamp is in an abnormal state when the detected value of the current detecting step is a value outside a predetermined range. And a stopping step of stopping the inverter operation and stopping the current supply to the discharge lamp when the discharge lamp is determined to be in an abnormal state by the determining step. Lamp abnormality detection method. 12. The discharge lamp according to claim 11, wherein the detected value is a peak value of current in both directions of the discharge lamp.
The method for detecting an abnormality of the discharge lamp described in the above. 13. The method according to claim 11, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp. 14. A lamp detecting step for detecting the presence or absence of the discharge lamp, wherein the stopping step includes stopping the inverter operation even when the absence of the discharge lamp is detected by the lamp detecting step. The discharge lamp abnormality detection method according to claim 9, wherein: 15. The method according to claim 11, wherein the discharge lamp is a fluorescent lamp. 16. A current detecting means for detecting a current value in both directions of a discharge lamp, and judging that the discharge lamp is in an abnormal state when a detected value of the current detecting means is out of a predetermined range. Discharging means, and stopping means for stopping an inverter operation and stopping current supply to the discharge lamp when the determining means determines that the discharge lamp is in an abnormal state. Lamp abnormality detection device. 17. The discharge lamp according to claim 16, wherein the detected value is a peak value of a current in both directions of the discharge lamp.
An abnormality detection device for a discharge lamp as described in the above. 18. The discharge lamp abnormality detecting device according to claim 16, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp. 19. A lamp detecting means for detecting the presence or absence of the discharge lamp, wherein the stopping means stops the inverter operation even when the lamp detecting means detects the absence of the discharge lamp. The discharge lamp abnormality detection device according to claim 16, wherein: 20. The apparatus according to claim 16, wherein the discharge lamp is a fluorescent lamp. 21. An inverter transformer, a switching transistor on a primary side of the inverter transformer, a dimming transistor on a secondary side of the inverter transformer, and a capacitive element connected in series between a discharge lamp and the inverter transformer. Ballast, current detecting means for detecting a current value in both directions of the discharge lamp, and stopping means for stopping the inverter operation when the detected value of the current detecting means is a value outside a predetermined range. An abnormality detection device for a discharge lamp. 22. The abnormality detecting apparatus for a discharge lamp according to claim 21, wherein said current detecting means is connected in series with said capacitive ballast and said discharge lamp. 23. The discharge lamp abnormality detecting device according to claim 21, wherein said current detecting means is connected in series with said switching transistor. 24. The device according to claim 21, wherein the current detecting means is connected in series with the dimming transistor.
An abnormality detection device for a discharge lamp as described in the above. 25. The discharge lamp according to claim 21, wherein the detected value is a peak value of a current in both directions of the discharge lamp.
An abnormality detection device for a discharge lamp as described in the above. 26. The abnormality detecting apparatus for a discharge lamp according to claim 21, wherein the detection value is an average value of absolute values of currents in both directions of the discharge lamp. 27. A system according to claim 27, further comprising a lamp detecting unit for detecting the presence or absence of a discharge lamp, wherein the stopping unit stops the inverter operation even when the lamp detecting unit detects that there is no discharge lamp. 22. The discharge lamp abnormality detection device according to claim 21. 28. The abnormality detecting apparatus for a discharge lamp according to claim 21, wherein the discharge lamp is a fluorescent lamp. 29. A storage medium storing a control program for controlling a discharge lamp abnormality detecting device for detecting an abnormality of a discharge lamp, wherein the control program detects a current value in both directions of the discharge lamp. And a control module for controlling to stop the inverter operation when the detected value is out of a predetermined range. 30. The discharge lamp according to claim 29, wherein the detected value is a peak value of a current in both directions of the discharge lamp.
The storage medium according to the above. 31. The storage medium according to claim 29, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp. 32. The storage medium according to claim 29, wherein the control program has a control module for controlling to stop the inverter operation even when the absence of the discharge lamp is detected. . 33. The storage medium according to claim 29, wherein said discharge lamp is a fluorescent lamp. 34. A storage medium storing a control program for controlling a discharge lamp abnormality detection device for detecting a discharge lamp abnormality, wherein the control program detects a current value in both directions of the discharge lamp. If the detected value is out of the predetermined range, it is determined that the discharge lamp is in an abnormal state, and control is performed so as to stop the inverter operation and stop the current supply to the discharge lamp. A storage medium having a step control module. 35. The discharge lamp according to claim 34, wherein the detected value is a peak value of a current in both directions of the discharge lamp.
The storage medium according to the above. 36. The storage medium according to claim 34, wherein the detected value is an average value of absolute values of currents in both directions of the discharge lamp. 37. The storage medium according to claim 34, wherein said discharge lamp is a fluorescent lamp.