KR20230067497A - Lighting device for discharge lamp and irradiation device for vehicle - Google Patents

Abstract

The present invention provides a lighting device for a discharge lamp and an irradiation device for a vehicle which can improve circuit efficiency. The lighting device for a discharge lamp according to an embodiment is a lighting device which applies a driving voltage of a predetermined frequency to a discharge lamp. The lighting device comprises: a first transformer which is electrically connected to one electrode of the discharge lamp; a second transformer which is electrically connected to the other electrode of the discharge lamp; and a switching output circuit which is electrically connected to the primary winding of the first transformer and the primary winding of the second transformer through a resonance condenser, and converts a direct current voltage into an alternating current voltage of a predetermined frequency by PWM control.

Description

Lighting device for discharge lamp and irradiation device for vehicle {LIGHTING DEVICE FOR DISCHARGE LAMP AND IRRADIATION DEVICE FOR VEHICLE}

An embodiment of the present invention relates to a lighting device for a discharge lamp and an irradiation device for a vehicle.

There is an ignition device for lighting the discharge lamp. For example, as a lighting device for lighting a dielectric barrier discharge lamp such as an excimer lamp, a lighting device having a pulse lighting circuit has been proposed. If the pulse lighting circuit is used, since a rest period can be provided in the current waveform of the discharge lamp at the time of lighting, the luminous efficiency of the discharge lamp can be improved. Further, in order to further improve the luminous efficiency of the discharge lamp, a pulse lighting circuit using a flyback circuit has also been proposed. However, a general pulse lighting circuit has a problem in that the circuit efficiency is low because the power loss in the transformer and the switching element is large. In addition, if the circuit efficiency is poor, the amount of heat generated by the circuit component increases, making it difficult to miniaturize the lighting device.

Then, development of a technique capable of improving circuit efficiency has been desired.

Japanese Unexamined Patent Publication No. 2000-200690

An object to be solved by the present invention is to provide a lighting device for a discharge lamp and an irradiation device for a vehicle capable of improving circuit efficiency.

A lighting device for a discharge lamp according to an embodiment is a lighting device that applies a driving voltage of a predetermined frequency to a discharge lamp. This lighting device includes a first transformer electrically connected to one electrode of the discharge lamp; a second transformer electrically connected to the other electrode of the discharge lamp; and a switching output circuit electrically connected to the primary winding of the first transformer and the primary winding of the second transformer through a resonant capacitor and converting a DC voltage into an AC voltage of a predetermined frequency by PWM control. is provided.

According to the embodiment of the present invention, it is possible to provide a lighting device for a discharge lamp and an irradiation device for a vehicle capable of improving circuit efficiency.

1 is a schematic perspective view for illustrating a vehicle irradiation device according to the present embodiment.
FIG. 2 is a schematic cross-sectional view of the vehicle irradiation device in FIG. 1 along line AA.
3 is a circuit diagram illustrating a lighting device.
4 is a circuit diagram for illustrating a lighting device according to another embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment is illustrated, referring drawings. In addition, in each drawing, the same code|symbol is attached|subjected to the same component, and detailed description is abbreviate|omitted suitably.

Although there is no particular limitation on the use of the lighting device for discharge lamps according to the present embodiment, it can be used, for example, for vehicle irradiation devices installed in vehicles such as automobiles and railroads. Therefore, below, as an example, a case where a lighting device for a discharge lamp is installed in a vehicle irradiation device will be described.

The vehicle irradiation device can be installed, for example, in a car interior or trunk room of a car, or installed in a car interior of a railroad car or the like. However, the installation location of the vehicle irradiation device is not limited to the illustrated ones.

1 is a schematic perspective view for illustrating a vehicle irradiation device 100 according to the present embodiment.

FIG. 2 is a schematic cross-sectional view of the vehicle irradiation device 100 in FIG. 1 along line A-A.

1 and 2, the vehicle irradiation device 100 includes, for example, a lighting device 1, a housing 2, a substrate 3, a discharge lamp 4, a lamp cover 5, Wiring 6, window 7 and shield 8 are provided.

First, the lighting device 1 according to this embodiment is illustrated.

As shown in FIG. 2 , the lighting device 1 is installed inside the housing 2 . The lighting device 1 is installed, for example, on the surface of the substrate 3 on the side where the discharge lamp 4 is installed. If the discharge lamp 4 and the lighting device 1 are provided on the same side surface of the board|substrate 3, it becomes easy to make thickness dimension T of the housing 2 small. The lighting device 1 is electrically connected to a pair of terminal holders 41 to which the discharge lamp 4 is mounted, using a wiring member such as a wiring cord or a metal plate, for example. Therefore, by attaching the discharge lamp 4 to the pair of terminal holders 41, the lighting device 1 and the discharge lamp 4 can be electrically connected.

The lighting device 1 applies a drive voltage of a predetermined frequency to the discharge lamp 4 . In addition, the lighting device 1 controls the value of the drive voltage applied to the discharge lamp 4 . When a drive voltage is applied to the discharge lamp 4, a discharge occurs between a pair of electrodes provided in the discharge lamp 4, for example, and light such as ultraviolet rays is radiated from the discharge lamp 4.

3 is a circuit diagram for illustrating the lighting device 1 .

As shown in FIG. 3, the lighting device 1 includes, for example, a switching output circuit 11, a transformer 12 (corresponding to examples of the first transformer and the second transformer), a resonance capacitor 13, It has a detection part 14 and a control circuit 15.

The switching output circuit 11 is electrically connected to the primary side windings of the two transformers 12 via a capacitor 13 for resonance. The switching output circuit 11 converts a DC voltage into an AC voltage of a predetermined frequency by PWM (Pulse Width Modulation) control. For example, the switching output circuit 11 converts the DC voltage from the DC power supply 200 into an AC voltage of a predetermined frequency, for example, a pseudo sine wave voltage. Also, the switching output circuit 11 changes the voltage applied to the primary side winding of the transformer 12. The DC power supply 200 is, for example, a battery or a battery installed in a vehicle such as a car.

The switching output circuit 11 illustrated in FIG. 3 is a half-bridge circuit. The switching output circuit 11, which is a half-bridge circuit, has, for example, a switching element 11a, a switching element 11b, and a driving circuit 11c.

The switching element 11a and the switching element 11b are, for example, MOSFETs (Metal-Oxide-Semiconductor Field Effect TransistorField effect transistors). If the switching elements 11a and 11b are MOSFETs that are voltage-driven elements, power loss in the circuit can be reduced. In addition, if the switching element 11a and the switching element 11b are MOSFETs, the speed of switching and the reduction of switching loss can be aimed at.

The drive circuit 11c controls, for example, application of a voltage to the gate electrode of the switching element 11a and the gate electrode of the switching element 11b, based on a control signal (PWM signal) from the control circuit 15. By alternately switching the application of voltage to, the DC voltage from the DC power supply 200 is converted into an AC voltage of a predetermined frequency. For example, the frequency is about 100 kHz to 300 kHz. In addition, the drive circuit 11c can change the output voltage (voltage applied to the primary winding of the transformer 12) by changing the duty ratio based on the PWM signal from the control circuit 15.

In addition, although the case where the switching output circuit 11 is a half bridge circuit was illustrated, the switching output circuit 11 may be, for example, a full bridge circuit or the like.

Two transformers 12 are installed. As described above, the primary side windings of the two transformers 12 are electrically connected to the switching output circuit 11. The secondary winding of one transformer 12 is electrically connected to one electrode of the discharge lamp 4 . The secondary winding of the other transformer 12 is electrically connected to the other electrode of the discharge lamp 4 . That is, it consists of two high-voltage discharges with the midpoint of the transformer 12 as the ground (reference).

Here, if the discharge lamp 4 is simply lit with a sinusoidal alternating current, the circuit efficiency deteriorates. Therefore, there is a possibility that the luminous efficiency of the discharge lamp 4 deteriorates. Since the LLC resonance circuit having the switching output circuit 11, the transformer 12, and the resonance capacitor 13 is provided in the lighting device 1 according to this embodiment, the switching loss of the circuit can be reduced. Therefore, since the circuit efficiency can be improved, the total efficiency including the discharge lamp 4 and the circuit can be improved.

Moreover, since circuit efficiency can be improved, the amount of heat generated by circuit components can be reduced or the lighting device 1 can be made small. If the lighting device 1 becomes smaller, the size of the vehicle irradiation device 100 in which the lighting device 1 is installed can be reduced. The vehicle irradiation device 100 is often installed in a narrow space such as a vehicle interior. Therefore, if the lighting device 1 can be downsized, installation of the vehicle irradiation device 100 becomes easy.

Here, there are cases where the DC voltage from the DC power supply 200 fluctuates greatly. For example, a DC power source 200 (eg, a battery) installed in a vehicle such as an automobile is electrically connected to the lighting device 1 installed in the vehicle irradiation device 100 . In general, the rated voltage of the DC power supply 200 installed in vehicles such as automobiles is about 13.5 V.

However, in practice, the voltage of the DC power supply 200 may fluctuate, for example, in the range of 9 V to 16 V due to a voltage drop of the battery, operation of the alternator, influence of the circuit, and the like. As the fluctuation of the voltage input to the lighting device 1 increases, the fluctuation of the driving voltage output from the lighting device 1 and applied to the discharge lamp 4 increases. If the fluctuation of the drive voltage becomes large, there is a possibility that the amount of light, such as light irradiated from the discharge lamp 4 or ultraviolet light, becomes unstable.

So, the detection part 14 and the control circuit 15 are provided in the lighting device 1.

The detection unit 14 detects the output state of the transformer 12. The detection unit 14 can be installed in each of the two transformers 12, for example. The detection unit 14 can be an auxiliary winding installed in the transformer 12, for example. If the detector 14 is an auxiliary winding, the current flowing in the secondary winding of the transformer 12 (output state of the transformer 12) can be detected by detecting the current flowing through the auxiliary winding.

The control circuit 15 inputs an appropriate PWM signal to the switching output circuit 11 (drive circuit 11c) based on the output state of the transformer 12 detected by the detection section 14.

The control circuit 15 has, for example, a PWM control circuit 15a, a comparator 15b, a reference voltage section 15c, and an LLC control circuit 15d.

The PWM control circuit 15a generates a PWM signal.

The comparator 15b compares the output state of the transformer 12 detected by the detection unit 14 with a reference value from the reference voltage unit 15c to detect the amount of change in the drive voltage due to the change in DC voltage. For example, the comparator 15b compares the voltage based on the current detected by the detection unit 14 and the reference voltage from the reference voltage unit 15c. In this way, the variation amount of the drive voltage applied to the discharge lamp 4 resulting from the voltage variation of the DC power supply 200 can be detected.

The LLC control circuit 15d inputs a PWM signal used for PWM control to the switching output circuit 11 (drive circuit 11c). The LLC control circuit 15d changes the duty ratio in the PWM signal generated by the PWM control circuit 15a based on the variation amount of the drive voltage applied to the discharge lamp 4, which is detected by the comparator 15b. . For example, when the driving voltage applied to the discharge lamp 4 is lower than the reference value (when the voltage of the DC power supply 200 is lowered), the LLC control circuit 15d adjusts the duty ratio of the PWM signal to discharge. It is increased according to the reduction amount of the drive voltage applied to the lamp 4. For example, when the driving voltage applied to the discharge lamp 4 is higher than the reference value (when the voltage of the DC power supply 200 increases), the LLC control circuit 15d sets the duty ratio of the PWM signal to the discharge lamp It is lowered according to the increase in driving voltage applied to (4). That is, the control circuit 15 performs feedback control on the switching output circuit 11 (drive circuit 11c) based on the output state of the transformer 12 detected by the detection section 14.

Since the detection unit 14 and the control circuit 15 are provided in the lighting device 1 according to the present embodiment, even if the voltage of the DC power supply 200 fluctuates, the driving voltage applied to the discharge lamp 4 fluctuations can be suppressed. Therefore, even if the voltage of the DC power supply 200 fluctuates, the quantity of light such as light or ultraviolet light emitted from the discharge lamp 4 can be stabilized.

In addition, since the LLC resonance circuit having the switching output circuit 11, the transformer 12, and the resonance capacitor 13 is operated intermittently by PWM control, even if the voltage of the DC power supply 200 fluctuates, the discharge lamp 4 ) It is possible to maintain the peak value of the driving voltage applied to. Therefore, the quantity of light, such as light irradiated from the discharge lamp 4 and an ultraviolet-ray, can be stabilized.

4 is a circuit diagram for illustrating a lighting device 1a according to another embodiment.

As shown in Fig. 4, the lighting device 1a has, for example, a switching output circuit 11, a transformer 12, a resonance capacitor 13, a detection unit 14, and a control circuit 15.

The configuration of the lighting device 1a can be the same as that of the lighting device 1 described above. However, in the case of the lighting device 1 described above, the detection unit 14 is provided in each of the two transformers 12. On the other hand, in the case of the lighting device 1a, the detection unit 14 is installed in either one of the two transformers 12. In other words, the detection unit 14 only needs to detect the output state of at least one of the two transformers 12 .

For example, when the characteristics of the transformer 12 are stable, the above-described feedback control may be performed based on the output state of one transformer 12.

In this way, miniaturization and cost reduction of the lighting device 1a can be achieved.

Next, returning to Figs. 1 and 2, housing 2, board 3, discharge lamp 4, lamp cover 5, wiring 6, window 7 installed in vehicle irradiation device 100 ) and the shield (8).

As shown in FIGS. 1 and 2, the housing 2 has a box shape and has a space for accommodating the substrate 3, the discharge lamp 4, the lamp cover 5 and the lighting device 1 therein. have The thickness T of the housing 2 may be smaller than the planar dimension of the housing 2 . The vehicle irradiation device 100 may be installed together with electronic devices used for vehicle operation in a narrow space such as a vehicle interior. Therefore, if the thickness dimension T of the housing 2 can be made small, installation of the vehicle irradiation device 100 becomes easy.

Further, the housing 2 is divided into a first part 21 and a second part 22 in the thickness direction of the housing 2 . The first portion 21 can serve as a base to which the substrate 3, the discharge lamp 4, the lamp cover 5, and the lighting device 1 are attached, for example. The 2nd part 22 can be made into the cover which covers the opening side of the 1st part 21, for example. A hole 22a for emitting ultraviolet light or light may be installed in the second part 22 . The hole 22a can be provided at a position facing the discharge lamp 4.

The second part 22 may be detachably installed on the first part 21 . For example, the 1st part 21 and the 2nd part 22 are connected so that attachment or detachment is possible by the elastic force generated by fitting openings together.

The first part 21 and the second part 22 can be formed of, for example, insulating resin. In this case, the material of the second portion 22 may be the same as or different from that of the first portion 21 . If the first part 21 and the second part 22 have insulation, the distance between the inner wall of the first part 21 and the second part 22 and the discharge lamp 4 and the lighting device 1 and the like can be shortened. Therefore, thinning of the housing 2 becomes easy.

The substrate 3 has a plate shape. The substrate 3 may be installed on the first portion 21 through, for example, a spacer 31 or the like. Alternatively, instead of the spacer 31 , the substrate 3 may be provided on the convex portion provided on the first part 21 .

The discharge lamp 4 is located between the substrate 3 and the second part 22 . The discharge lamp 4 can be installed in a position facing the hole 22a of the second part 22 . The discharge lamp 4 can be detachably attached to the pair of terminal holders 41 . A pair of terminal holders 41 can be installed on the substrate 3, for example. In addition, although the case where one discharge lamp 4 is installed was illustrated in FIGS. 1-4, you may make it the some discharge lamp 4 be installed. The discharge lamp 4 should just be provided at least one.

The discharge lamp 4 can be, for example, a mercury lamp, a metal halide lamp, or a dielectric barrier discharge lamp. However, the discharge lamp 4 is not limited to what was illustrated, What is necessary is just to be able to irradiate an ultraviolet-ray or light (for example, visible light).

The lamp cover 5 is located between the substrate 3 and the second part 22 . The lamp cover 5 can be installed on the substrate 3, for example. The lamp cover 5 has a box shape, and the surface opposite to the substrate 3 side is open. The opening 5a of the lamp cover 5 faces the hole 22a of the second part 22 . Inside the lamp cover 5, a discharge lamp 4 and a pair of terminal holders 41 can be installed. For example, the lamp cover 5 may be formed of resin having insulating properties. The material of the lamp cover 5 can be the same as that of the housing 2, for example. However, since the lamp cover 5 is exposed to ultraviolet rays emitted from the discharge lamp 4, it is preferable to use a material having higher resistance to ultraviolet rays than the material of the housing 2.

When the lamp cover 5 is installed, it is possible to suppress ultraviolet light or light irradiated from the discharge lamp 4 from entering the inner wall of the housing 2, the substrate 3, and the lighting device 1. Therefore, it can suppress that these deteriorate by an ultraviolet-ray etc.

In addition, the lamp cover 5 may have a reflector function. For example, the lamp cover 5 may be formed of resin such as white, a reflective film may be formed on the inner wall of the lamp cover 5, or the inner wall of the lamp cover 5 may be curved. By giving the lamp cover 5 the function of a reflector, the utilization efficiency of the ultraviolet rays or light irradiated from the discharge lamp 4 can be improved.

One end of the wiring is electrically connected to the lighting device 1 inside the housing 2 . The other end of the wiring is led out of the housing 2 and electrically connected to, for example, a DC power supply 200 .

The window 7 is installed in a portion of the housing 2 (second portion 22) where the hole 22a is provided. For example, the window 7 is installed on the inner wall of the second part 22 and covers the hole 22a. The window 7 transmits ultraviolet light or light irradiated from the discharge lamp 4 . Window 7 has a plurality of openings, for example. The window 7 can be, for example, formed by weaving a plurality of wire rods, or formed by forming a plurality of openings by etching, press working, or the like.

Here, when the discharge lamp 4 is turned on, when discharge occurs between the electrodes of the discharge lamp 4, electromagnetic waves may be radiated together with ultraviolet light or light. Also, when the discharge lamp 4 is turned on, electromagnetic waves may be radiated from the switching elements 11a and 11b provided in the lighting device 1 or wires electrically connected to the switching elements 11a and 11b.

As described above, the vehicle irradiation device 100 may be installed in a narrow space such as a vehicle interior together with electronic devices used for driving a vehicle. In such a case, the distance between the vehicle irradiation device 100 and the electronic device tends to be short. Therefore, when electromagnetic waves generated by the discharge lamp 4 or the lighting device 1 installed inside the housing 2 are radiated to the outside of the housing 2, electromagnetic waves are emitted to electronic devices installed near the vehicle irradiation device 100. may be incorporated. When an electromagnetic wave is incident on an electronic device, it becomes electromagnetic wave noise and there is a possibility that the electronic device may malfunction or the like.

Therefore, the shield 8 is installed in the vehicle irradiation device 100 according to the present embodiment.

The shield 8 suppresses electromagnetic waves generated inside the housing 2 from being radiated to the outside of the housing 2 . The shield 8 has conductivity and can be installed on the outer wall of the housing 2, for example. When the shield 8 having conductivity is used, reflection loss in the shield 8 can be increased, so that electromagnetic waves generated inside the housing 2 can be effectively suppressed from being radiated to the outside of the housing 2 .

In this case, the shield 8a may be installed on the outer wall of the first part 21 and the shield 8b may be installed on the outer wall of the second part 22 . And, in the connection part 2a of the 1st part 21 and the 2nd part 22, the shield 8a provided on the outer wall of the 1st part 21, and the outer wall of the 2nd part 22 provided The shield 8b can be brought into contact. For example, the shield 8a can also be provided at the end of the first portion 21 on the opening side, and the shield 8b can also be provided at the end of the second portion 22 on the opening side.

In this way, the shield 8a and the shield 8b can be electrically connected. Therefore, since the shield 8a and the shield 8b can be electrically connected to the ground of the vehicle, reduction of the shield effect can be suppressed.

As described above, the window 7 is provided with a plurality of openings through which ultraviolet rays or light irradiated from the discharge lamp 4 are transmitted. Therefore, there is a possibility that electromagnetic waves may be radiated to the outside of the housing 2 through the plurality of openings provided in the window 7 . In this case, when the shield 8 is installed on the outer surface of the window 7, ultraviolet light or light is not irradiated to the outside of the housing 2.

Therefore, the window 7 is intended to have conductivity. For example, window 7 is formed of a conductive material. The conductive material can be the same as the conductive material used for the shield 8, for example. In this case, if the conductive material is a metal, resistance to ultraviolet rays or the like irradiated from the discharge lamp 4 can be improved.

If the window 7 has conductivity, as in the case of the shield 8 described above, reflection loss at the window 7 can be increased, so electromagnetic waves pass through the window 7 to the outside of the housing 2. radiation can be suppressed.

Further, if the window 7 is not electrically connected to the ground of the vehicle, the shielding effect of the window 7 may be reduced. Therefore, the window 7 can be electrically connected to the shield 8 installed in the housing 2.

As mentioned above, although several embodiments of this invention were illustrated, these embodiments are presented as an example, and there is no intention to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, changes, and the like can be implemented within a range not departing from the gist of the invention. While being included in the scope and gist of the invention, these embodiments and modifications thereof are included in the invention described in the claims and the range of their equivalents. In addition, each embodiment mentioned above can be implemented in combination with each other.

1, 1a: lighting device 2: housing
4: discharge lamp 11: switching output circuit
11a, 11b: switching element 11c: drive circuit
12: transformer 13: capacitor for resonance
14: detection unit 15: control circuit
15a: PWM control circuit 15b: comparator
15c: reference voltage unit 15d: LLC control circuit
100: Vehicle irradiation device 200: DC power

Claims (5)

A lighting device for applying a driving voltage of a predetermined frequency to a discharge lamp,
a first transformer electrically connected to one electrode of the discharge lamp;
a second transformer electrically connected to the other electrode of the discharge lamp; and
a switching output circuit electrically connected to the primary winding of the first transformer and the primary winding of the second transformer through a resonant capacitor and converting a DC voltage into an AC voltage of a predetermined frequency by PWM control;
A lighting device for a discharge lamp having a. According to claim 1,
a detector detecting an output state of at least one of the first transformer and the second transformer;
a comparator that compares the output state detected by the detection unit with a reference value, and detects a variation amount of the drive voltage, which is caused by a variation of the DC voltage; and
an LLC control circuit for inputting a PWM signal used for the PWM control to the switching output circuit;
additionally provided,
wherein the LLC control circuit changes a duty ratio in the PWM signal based on the variation amount of the drive voltage detected by the comparator. According to claim 2,
Wherein the detection unit is an auxiliary winding installed in at least one of the first transformer and the second transformer. According to claim 2 or 3,
The LLC control circuit intermittently controls the switching output circuit, a lighting device for a discharge lamp. As a vehicle irradiation device installed in the vehicle;
with discharge lamp;
a lighting device for a discharge lamp according to any one of claims 1 to 4 electrically connected to the discharge lamp;
Having a vehicle irradiation device.

Images