JP2013149366A - Light source device with discharge tube lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electromagnetic wave noise, generated when a discharge lamp is lighted, from affecting a sub-circuit.SOLUTION: A main circuit 6 includes a signal switching section 10 and a sub-circuit power supply 12, in addition to an arithmetic control section 8. The signal switching section 10 is interposed electrically between a sub-circuit 4 and the arithmetic control section 8, and switches interruption and connection of the signal path. The sub-circuit power supply 12 performs on/off switching of power supply for operating the sub-circuit 4. Before the discharge lamp of a lamp lighting section 2 is lighted, a lighting start signal of the discharge lamp is transmitted to the signal switching section 10 and the sub-circuit power supply 12 from the arithmetic control section 8, and the power supply of the sub-circuit 4 is turned off by the sub-circuit power supply 12, or the signal path between the sub-circuit 4 and the arithmetic control section 8 is interrupted by the signal switching section 10.

Description

  The present invention relates to a light source device including a discharge tube lamp in an analyzer such as a liquid chromatograph detector, a spectrophotometer, and a nuclear absorptiometer.

  A discharge tube lamp is a lamp that causes a dielectric breakdown due to a voltage applied between electrodes, and utilizes a light emission phenomenon caused by excitation of a gas in the tube when a current flows. Typical examples include a xenon lamp and a deuterium lamp. (For example, refer to Patent Document 1). These lamps are generally used in devices such as liquid chromatograph detectors and spectrophotometers. In these devices, a trigger voltage is applied between the electrodes in the discharge tube when the discharge tube lamp is turned on to cause a dielectric breakdown, and then a voltage for maintaining a discharge between the electrodes and a current value flowing between the electrodes are applied. The light emission amount is controlled to be constant by constant current control so that is constant, and is used for measurement.

JP 2005-209418 A

  The trigger voltage required to light the discharge tube lamp is about 30 kV for the xenon lamp and about 600 V for the deuterium lamp, but it is known that electromagnetic noise is generated when such a high voltage is applied. The circuit board malfunctions due to electromagnetic noise.

  Since electromagnetic wave noise when the discharge tube lamp is lit is generated from the discharge tube lamp or a cable (lamp cable) connected to the discharge tube lamp, regarding the arrangement of the discharge tube lamp, the cable and the circuit board in the apparatus, the discharge tube lamp Electromagnetic noise on the circuit board by placing restrictions such as placing an electromagnetic shielding material between the lamp cable and the circuit board, making the cable as short as possible, or not placing the circuit board around the discharge tube lamp or cable It was necessary to prevent the effects of.

When the main circuit board and the sub circuit board exist separately due to the board configuration in the apparatus, each is normally connected to a signal (signal) cable, but this connection cable is generally susceptible to electromagnetic noise. Therefore, when the sub circuit board is disposed in the vicinity of the lamp cable, malfunction due to electromagnetic wave noise is likely to occur.
If the lamp cable is lengthened, a large electromagnetic noise will be generated and cause the malfunction of the sub circuit. Therefore, in a device in which the sub circuit board is arranged in the vicinity of the lamp cable or the like, the discharge tube lamp is replaced when the discharge tube lamp is replaced. It was difficult to make a structure that can be pulled out from the inside of the apparatus.

  In addition, if the sub-circuit in which the nonvolatile memory is mounted is disposed in the immediate vicinity of the discharge tube lamp, the control signal to the nonvolatile memory is swung to an unintended voltage due to the influence of electromagnetic wave noise, and the stored contents are rewritten. Therefore, it is difficult to provide a sub-circuit for storing information such as the total lighting time and the number of lighting times of the discharge tube lamp on the replaceable part (discharge tube lamp) side.

  Therefore, an object of the present invention is to prevent electromagnetic noise generated when a discharge tube lamp is lit from affecting a sub circuit.

A light source device according to the present invention discharges a discharge tube lamp, a trigger power supply unit that starts a discharge by applying a trigger voltage to the discharge tube lamp, and a discharge sustain voltage for maintaining the discharge state of the discharge tube lamp that has started the discharge. A discharge sustaining power supply to be applied to the tube lamp, and a main circuit for turning on and off the discharge tube lamp, and a lamp lighting unit and a sub circuit provided separately from the main circuit, the main circuit being a sub circuit A sub-circuit control unit for controlling the operation is also provided. When the trigger voltage is applied to the discharge tube lamp in the lamp lighting unit, the sub-circuit control unit cuts off the voltage applied to the sub-circuit and stops the operation of the sub-circuit. It is configured.
The sub circuit refers to a circuit board configured on a board different from the main circuit that controls the lighting operation of the lamp. As an example of the sub-circuit, there is one in which a nonvolatile memory is mounted and information related to maintenance such as the number of times the lamp is turned on is stored in the circuit board.

  In the present invention, the light source device is electrically connected to the main circuit, and further includes a connection switching unit capable of switching between electrical connection and disconnection between the main circuit and the sub circuit, and the control unit includes: The operation of the connection switching unit is also controlled, and the electrical connection between the main circuit and the sub circuit is preferably cut off when a trigger voltage is applied to the discharge tube lamp. By doing so, it is possible to prevent malfunction of the sub circuit (for example, rewriting of the stored contents of the nonvolatile memory) due to electromagnetic wave noise generated when the discharge tube lamp is turned on.

  In a preferred embodiment, the sub-circuit control unit includes a power switch that switches on / off of voltage application to the sub-circuit based on a trigger signal generated by the lamp lighting control unit when a trigger voltage is applied to the discharge tube lamp. Yes. Thereby, the configuration of the sub-circuit control unit can be simplified.

  Furthermore, it is preferable that the sub circuit control unit further includes a signal switch that switches connection and disconnection of a signal path between the main circuit and the sub circuit based on a trigger signal. Then, electromagnetic noise can be prevented from entering the sub circuit side through the signal path.

  In the light source device of the present invention, the main circuit includes a sub circuit control unit that controls the operation of the sub circuit, and the sub circuit control unit applies the trigger voltage to the discharge circuit lamp in the lamp lighting unit. Since it is configured to stop the operation of the sub-circuit by cutting off the voltage, the power supply to the sub-circuit board is stopped when the trigger voltage, which is a high voltage, is applied to the discharge tube lamp and electromagnetic wave noise is generated This prevents the sub circuit board from malfunctioning when the discharge tube lamp is turned on. Therefore, it is possible to install the sub circuit board around the discharge tube lamp and the lamp cable.

It is a block diagram which shows roughly one Example of the apparatus provided with the discharge tube lamp. It is a circuit diagram which shows an example of the lamp lighting part of the Example. It is a flowchart which shows operation | movement of the Example. It is a block diagram which shows the connection and interruption | blocking of the power supply and signal path | route in FIG. It is a figure which shows an example of the signal waveform in the example of FIG.

An embodiment of a light source device having a discharge tube lamp will be described with reference to FIG.
This light source device is a light source device that includes a discharge tube lamp, includes a lamp lighting unit 2 for turning on / off the lamp, and performs measurement using light emitted from the discharge tube lamp of the lamp lighting unit 2. . In the vicinity of the lamp lighting unit 2, a sub-circuit 4 including a non-volatile memory that stores information (maintenance information) such as the lighting time and the number of times of lighting of the discharge tube lamp of the lamp lighting unit 2 is provided.

  Both the operation of turning on and off the discharge tube lamp in the lamp lighting unit 2 and the operation of the sub circuit 4 are controlled by an arithmetic control unit 8 as a lamp lighting control unit provided in the main circuit 6. The arithmetic control unit 8 is constituted by a CPU, for example. The lamp lighting unit 2 and the sub circuit 4 are configured to transmit and receive signals via the main circuit 6. The maintenance information of the lamp lighting unit 2 is input to the sub circuit 4 via the arithmetic control unit 8, and the maintenance information input to the sub circuit 4 is stored in a non-volatile memory mounted on the sub circuit 4. Remembered. Conversely, the maintenance information stored in the non-volatile memory of the sub-circuit 4 is read out by the arithmetic control unit 8 and is discharged when, for example, the lighting time or the number of lighting times of the discharge tube lamp reaches a predetermined replacement guide value. It is used for the management of discharge tube lamps, such as displaying a prompt to replace the tube lamps.

  The main circuit 6 includes a signal switching unit 10 and a sub circuit power supply unit 12 in addition to the arithmetic control unit 8. The signal switching unit 10 is electrically connected between the sub-circuit 4 and the arithmetic control unit 8, and switches between blocking and connecting the signal path. The sub-circuit power supply unit 12 switches on / off the power supply for operating the sub-circuit 4. The signal switching unit 10 and the sub circuit power supply unit 12 constitute a sub circuit control unit. Before the discharge tube lamp of the lamp lighting unit 2 is turned on, the signal switching unit 10 and the sub circuit power supply unit 12 are configured to transmit a lighting start signal of the discharge tube lamp from the arithmetic control unit 8. The signal switching unit 10 and the sub circuit power supply unit 12 are configured to cut off the signal path between the sub circuit 4 and the arithmetic control unit 8 and switch off the power supply of the sub circuit 4 according to the signal.

  An example of a specific configuration of the lamp lighting unit 2 is shown in FIG. The lamp lighting unit 2 shown in this example lights a deuterium lamp 14 that is a discharge tube lamp. The lamp lighting unit 2 includes a lamp 14, a heater power supply 16, a trigger power supply unit 18, and a constant current power supply unit 20. The heater power supply unit 16 applies voltage to the heater of the deuterium lamp 14 to heat it. The trigger power supply unit 18 is for applying a trigger voltage for causing discharge between the electrodes of the deuterium lamp 14. The trigger power supply unit 18 includes a power supply 22, a capacitor 24, a trigger resistor 26, and a trigger switch 28. When the deuterium lamp 14 is turned on, the trigger switch 28 is switched to change the voltage stored in the capacitor 24 into deuterium. Applied to the lamp 14. The constant current power supply unit 20 applies an anode voltage to the electrodes of the deuterium lamp 14 and also applies a discharge sustaining voltage between the electrodes of the deuterium lamp 14 that has started discharging.

  The arithmetic control unit 8 controls the operation of the trigger power supply unit 18. When starting the lighting operation of the deuterium lamp 14, the heater of the deuterium lamp 14 is heated and can be turned on, and the trigger switch 28 of the trigger power supply unit 18 stores a trigger voltage in the capacitor 24. Is in a state of configuring. The arithmetic control unit 8 gives a signal (trigger signal) for switching the trigger switch 28 to the trigger switch 28, the trigger switch 28 is switched, and the trigger voltage stored in the capacitor is applied to the deuterium lamp 14.

  The operation control unit 8 in FIG. 1 cuts off the signal path between the sub circuit 4 and the operation control unit 8 with respect to the signal control unit 10 and the sub circuit power supply unit 12 before giving a trigger signal to the trigger switch 28. A signal is transmitted to turn off the power of the sub circuit 4.

Details of the lighting operation of the discharge tube lamp in the apparatus of this embodiment will be described with reference to FIG. 3 together with FIGS.
First, a heater voltage is applied from the heater power supply 16 to the discharge tube lamp (deuterium lamp) 14 and an anode voltage is applied from the constant current power supply unit 20 (step S1). At this time, the power supply 22 is turned on in the trigger power supply unit 18, and the voltage is stored in the capacitor 24.

  After a predetermined time has passed, it is confirmed whether or not the sub circuit 4 is operating (step S2). If it is confirmed that the sub circuit 4 is not operating, the sub circuit power supply unit 12 performs the sub circuit operation. 4 is turned off, and the signal path between the main circuit 6 (calculation control unit 8) and the sub circuit 4 is blocked by the signal control unit 10 (step S3). When the sub circuit 4 is in operation, it waits until the operation of the sub circuit 4 is completed, and after the operation of the sub circuit 4 is completed, the sub circuit power supply unit 12 turns off the power of the sub circuit 4. The signal path between the main circuit 6 and the sub circuit 4 is blocked by the signal control unit 10 (step S3).

  The trigger stored in the capacitor 24 by switching the trigger switch 18 of the trigger power supply unit 18 in a state where the power of the sub circuit 4 is off and the signal path between the main circuit 6 and the sub circuit 4 is cut off. A voltage is applied to the discharge tube lamp 14 (step S4). When a trigger voltage is applied to the discharge tube lamp 14, electromagnetic noise is generated by a magnetic field due to a high voltage, but the power supply of the sub circuit 4 is turned off and the signal path to the main circuit 6 is completely cut off. Therefore, the sub circuit 4 does not malfunction and the contents of the nonvolatile memory are not rewritten.

  After the discharge is started between the electrodes of the discharge tube lamp 14 by the application of the trigger voltage, the discharge is maintained by the discharge sustain voltage from the constant current power supply unit 20, and the discharge tube lamp 14 is turned on (step S5). When the discharge tube lamp 14 is normally lit, the power supply of the sub circuit 4 is turned on and the signal path between the main circuit 6 and the sub circuit 4 is connected to return the sub circuit 4 to the normal operation state. (Step S6). Then, information such as the number of lighting of the discharge tube lamp 14 is stored in the nonvolatile memory of the sub circuit 4 (step S7).

  If the discharge tube lamp 14 does not light normally even when the trigger voltage is applied (step S5), the trigger voltage is repeatedly applied a predetermined number of times (step S8). If not, the operator is notified of an error (step S9).

  In the embodiment of FIG. 2, a deuterium lamp is used as the discharge tube lamp. However, the present invention is not limited to this, and can be similarly applied to, for example, a xenon lamp.

The connection and interruption of the power supply and the signal path in the example of FIG. 1 will be described with reference to FIG.
The main circuit 6 includes a power switch 12 a that switches on / off of application of a voltage of 5 V for driving the sub circuit 4, a signal switch 10 a that switches off and connects the write signal path to the sub circuit 4, and the sub circuit 4. A signal switch 10b for switching between disconnection and connection of the information read signal path. The power switch 12 a constitutes the sub-circuit power supply unit 12 in FIG. 1, and the signal switches 10 a and 10 b constitute the signal switching unit 10. The power switch 12a and the signal switches 10a and 10b are switched by a trigger signal from the arithmetic control unit 8 (FIG. 1).

  FIG. 5 shows the waveforms of electrical signals that flow through these signal paths. A is a 5V voltage output from the arithmetic control unit 8, B is a trigger signal output from the arithmetic control unit 8, C is a power supply voltage applied to the subcircuit, and D is an information write signal (write signal in FIG. After the signal is switched). When the B trigger signal is output (trigger voltage application), the power switch 12a is switched from the on state to the off state, and the applied voltage to the C sub circuit is cut off. At this time, the signal switches 10a and 10b are also switched to a state in which the signal path is cut off, and the information write signal to the sub circuit 4 is cut off as indicated by D.

  In the example of FIG. 5, the trigger signal is output for 3.4 seconds, and the electromagnetic wave noise when the lamp is lit ends within this time. After the trigger signal ends, the power switch 12a immediately restores the application of the power supply voltage to the sub circuit 4. On the other hand, the signal switches 10a and 10b return the signal path between the main circuit 6 and the sub circuit 4 after a predetermined time has elapsed after the trigger signal is finished. This is because it is necessary to perform a predetermined initialization operation after the power supply of the sub circuit 4 is restored.

  INDUSTRIAL APPLICABILITY The present invention can be used for an apparatus that performs various measurements using light obtained by lighting a discharge tube lamp such as a deuterium lamp or a xenon lamp, such as a spectrophotometer.

2 Lamp lighting unit 4 Sub circuit 6 Main circuit 8 Operation control unit 10 Signal switching unit 12 Sub circuit power source unit 14 Deuterium lamp 16 Heater power source 18 Trigger power source unit 20 Constant current power source unit 22 Power source 24 Capacitor 26 Trigger resistor 28 Trigger switch

Claims (4)

A discharge tube lamp, a trigger power supply unit that starts a discharge by applying a trigger voltage to the discharge tube lamp, and a discharge sustain voltage for maintaining a discharge state of the discharge tube lamp that has started a discharge are applied to the discharge tube lamp A discharge maintaining power source, a lamp lighting unit for turning on and off the discharge tube lamp;
A main circuit comprising a lamp lighting control unit for controlling the lighting operation of the discharge tube lamp of the lamp lighting unit;
A sub-circuit provided separately from the lamp lighting unit and the main circuit,
The main circuit also includes a sub circuit control unit that controls the operation of the sub circuit, and the sub circuit control unit applies a voltage to the sub circuit when a trigger voltage is applied to the discharge tube lamp in the lamp lighting unit. A light source device provided with a discharge tube lamp configured to stop the operation of the sub-circuit by interrupting the operation.   2. The light source device according to claim 1, wherein the sub circuit control unit is configured to cut off a signal path between the main circuit and the sub circuit when the trigger voltage is applied to the discharge tube lamp. .   The sub-circuit control unit includes a power switch that switches on / off of power supply voltage application to the sub-circuit based on a trigger signal generated by the lamp lighting control unit when a trigger voltage is applied to the discharge tube lamp. The light source device according to claim 2.   The light source device according to claim 3, wherein the sub circuit control unit further includes a signal switch that switches connection and disconnection of a signal path between the main circuit and the sub circuit based on the trigger signal.

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