JPH10302988A - Lighting device for discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a danger of short-circuiting on secondary side of a transformer, while the device is miniaturized. SOLUTION: This device is equipped with a discharge lamp La and a piezoelectric transformer 2 by which a high voltage is generated at a power generating part 4 by applying an alternate current voltage to a driving part 3 and electric power is transmitted to the discharge lamp La. In this case, while the piezoelectric transformer 2 is formed in a thin plate, the discharge lamp La is made of a direct tube type, and while the discharge lamp La is close mounted so that at least a part of it confronts to the power generating part 4 of the piezoelectric transformer 2, a cable of an outside connection line 6 is connected only to the driving part 3 of the piezoelectric transformer 2, a driving circuit 5 which oscillates in the neighborhood of a frequency close to a resonance frequency of the piezoelectric transformer 2 is connected to the driving part 3 of the piezoelectric transformer 2, so that lighting of the discharge lamp La is maintained by activating the piezoelectric transformer 2 in the neighborhood of a frequency close to the resonance frequency to transmit electric power from the power generating part 4 to the discharge lamp La.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a discharge lamp lighting device using a piezoelectric transformer.

[0002]

2. Description of the Related Art In recent years, discharge lamp lighting devices for lighting a discharge lamp at a high frequency have become widespread. In general, many discharge lamps increase the power supply voltage of a commercial power supply for starting and lighting. Therefore, most of the discharge lamp lighting devices have a boosting function in the high frequency lighting circuit. The required voltage varies depending on the discharge lamp. However, for example, a cold cathode lamp requires a starting voltage of 1 Kv or more, such as a cold cathode lamp. It is indispensable to have a boosting function for a vehicle.

FIG. 15 shows a conventional discharge lamp lighting device (first conventional example). This discharge lamp lighting device is an electromagnetic type by alternately turning on and off a pair of switching elements Q1 and Q2. A high frequency voltage is generated on the primary side of the winding transformer T, and the high frequency voltage is boosted by the winding transformer T to obtain a voltage sufficient for starting the discharge lamp La on the secondary side,
This secondary side is connected to each electrode of the discharge lamp La to discharge the discharge lamp La.
After the discharge lamp La is turned on, the capacitor C connected to the secondary side of the winding transformer T becomes a current-limiting element and the discharge lamp L is turned on.
a is stably lit.

FIG. 16 shows another conventional discharge lamp lighting apparatus (second conventional example), in which the output of the secondary side of the winding transformer T in the first conventional example is applied to both ends of a discharge lamp La. The power is transmitted to the discharge lamp La by being connected to the conductor foil 1 wound around the vicinity thereof. In this conventional example, the discharge lamp La is connected by capacitive coupling between the conductor foil 1 and the discharge lamp La. Is supposed to be lit.

FIG. 17 shows still another conventional discharge lamp lighting device (third conventional example) in which a piezoelectric transformer 2 is used to increase the voltage in place of the winding transformer T in the first conventional example. It is intended to be. This piezoelectric transformer 2
Uses a piezoelectric ceramic and the electrostriction phenomenon, and includes a driving unit 3 and a power generation unit 4. When a high frequency voltage is applied to the driving unit 3 as a primary voltage, mechanical vibration occurs due to the electrostriction phenomenon. The stress is transmitted through the inside of the piezoelectric ceramic to generate a stress and a displacement. At the same time, a piezoelectric phenomenon occurs in which a voltage proportional to the displacement is generated. By connecting each electrode of the discharge lamp La with an electric wire which is an external connection line between one electrode 3a of the drive unit 3 serving as a common electrode and the electrode 4a of the power generation unit 4, the voltage of the discharge lamp La is changed. Is applied to start and light up.

[0006]

However, in the discharge lamp lighting device shown in the first conventional example having such a configuration, the transformer that performs the boosting function is the electromagnetic winding transformer T, so that the core of the iron core is not used. Due to restrictions due to magnetic saturation, insulation design of the winding, mounting method, etc., there is not only a problem that the transformer becomes large, but also a troublesome winding,
There is a problem that the assembly process is required and the cost tends to be high. Further, since the discharge lamp La is lit by emitting electrons from the electrodes of the discharge lamp La, there is also a problem that the life of the discharge lamp is determined by the life of the electrode.

Further, in the discharge lamp lighting device shown in the second conventional example, the life of the discharge lamp La is not determined by the life of the electrodes, but otherwise the same problems as in the first conventional example. In addition, since the conductor foil 1 is wrapped around the vicinity of both ends of the discharge lamp La, they block the light and reduce the total luminous flux emitted from the discharge lamp La.

In the discharge lamp lighting device shown in the third conventional example, the secondary side, which is the power generation unit 4 of the piezoelectric transformer 2, and the discharge lamp La are connected by an electric wire, which is an external connection line. However, since a high voltage is applied to the electric wire, it is necessary to secure an insulation distance between the electric wire and other parts. Also, if the electric wire on the secondary side of the piezoelectric transformer 2 is short-circuited, the secondary current increases. There is a problem that the piezoelectric transformer 2 may be broken. Furthermore, since the discharge lamp La is lit by emitting electrons from the electrodes of the discharge lamp La, the life of the discharge lamp La is determined by the life of the electrodes.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a compact discharge lamp lighting device which eliminates the possibility of short-circuiting on the secondary side of a transformer.

[0010]

According to the present invention, in order to solve the above-mentioned problems, a high voltage is applied to a power generation unit by applying an AC voltage to a discharge lamp and a driving unit. In a discharge lamp lighting device including a piezoelectric transformer that generates power and transmits power to the discharge lamp, an external connection line is connected only to a driving unit of the piezoelectric transformer, and at least a part of the discharge lamp is connected to the power generation unit. The electric power is transmitted from the power generation unit to the discharge lamp by being disposed so as to be opposed to each other.

According to the second aspect of the present invention, the first aspect is provided.
The discharge lamp lighting device according to claim 1, wherein a driving circuit that oscillates near the resonance frequency of the piezoelectric transformer is connected to the driving unit of the piezoelectric transformer, and the piezoelectric transformer is operated near the resonance frequency. I do.

According to a third aspect of the present invention, in the discharge lamp lighting device according to the first or second aspect, the lighting of the discharge lamp is maintained by electric power transmitted from the piezoelectric transformer. It is characterized by.

According to the fourth aspect of the present invention, the third aspect is provided.
In the discharge lamp lighting device described above, the piezoelectric transformer is formed in a thin plate shape, and the discharge lamp is formed into a straight tube, and the discharge lamp is substantially parallel to a direction connecting the driving unit and the power generation unit of the piezoelectric transformer. It is characterized by being arranged.

[0014] According to the fifth aspect of the present invention, the third aspect is provided.
In the discharge lamp lighting device according to the above, the piezoelectric transformer is formed in a thin plate shape, and the discharge lamp is a discharge lamp having a U-shape, and the piezoelectric transformer is disposed in a space between the discharge lamps in the U-shape. It is characterized by having done.

According to the sixth aspect of the present invention, there is provided the third aspect.
The discharge lamp lighting device according to the above aspect, wherein a plurality of the piezoelectric transformers are arranged close to the discharge lamp.

According to the seventh aspect of the present invention, a third aspect is provided.
In the discharge lamp lighting device described above, the discharge lamp is dimmed by changing a distance between the piezoelectric transformer and the discharge lamp.

In the invention according to claim 8, claim 1 is provided.
In the discharge lamp lighting device described above, the discharge lamp is started by electric power transmitted from the piezoelectric transformer.

According to the ninth aspect of the present invention, there is provided an eighth aspect of the present invention.
In the discharge lamp lighting device described above, the discharge lamp is a high-pressure discharge lamp, and the piezoelectric transformer is disposed close to the arc tube.

According to a tenth aspect of the present invention, in the discharge lamp lighting device according to the eighth aspect, the discharge lamp is a high-pressure discharge lamp, the arc tube is formed of piezoelectric ceramic, and one end side is provided with a drive unit. Characterized in that it is a piezoelectric transformer.

[0020]

1 to 3 show a first embodiment of a discharge lamp lighting device according to the present invention. The discharge lamp lighting device comprises a piezoelectric transformer 2 and a driving circuit 5 for the piezoelectric transformer 2. , And is configured to light the discharge lamp La.

The piezoelectric transformer 2 has a ceramic material of PZT and a product number C213 manufactured by Fuji Ceramics Co., Ltd., and has a thin and thin shape having a thickness of 1.5 mm, a width of 6 mm and a length of 130 mm. A drive electrode 3a, which is a primary electrode formed by, for example, silver deposition, is formed on both front and back surfaces, and the drive electrode 3a is polarized in the thickness direction as indicated by an arrow A in FIG. 1 between the drive electrodes 3a. , And that part is the drive unit 3. On the other end side opposite to the side on which the drive electrode 3a is provided, polarization is performed in the length direction as indicated by an arrow B in FIG. Therefore, the vibration mode of the piezoelectric transformer 2 is a thickness-length vibration mode.

The drive circuit 5 drives the piezoelectric transformer 2 by being connected to the drive electrode 3a of the piezoelectric transformer 2 by an electric wire, which is an external connection line 6, and includes a switching element Q as shown in FIG. This is a single-type separately excited resonance type inverter oscillation circuit, which has a power of
A high frequency of 100 kHz from z is output. The piezoelectric transformer 2 is operated near, but not limited to, its resonance frequency. The discharge lamp La has a tube diameter of 4 mm and a length of 110 mm, for example.
mm cold cathode lamp, the tube axis of which is
Is disposed on the surface of the piezoelectric transformer 2 and is disposed in parallel with a portion of the piezoelectric transformer 2 where the drive electrode 3a is not provided. That is, in the piezoelectric transformer 2, the electric wire that is the external connection line 6 is connected only to the drive unit 3, and the external connection line is not connected to the power generation unit 4.

From such a piezoelectric transformer 2, the discharge lamp La
In order to transmit electric power to the power generation unit 4, a secondary electrode is also provided in the power generation unit 4 and the electrode of the discharge lamp La is connected to an external connection wire which is a secondary electric wire. As a result of repeated experiments, the inventor of the present application has found that the piezoelectric transformer 2 and the discharge lamp La are appropriately disposed close to each other, and the resonance conditions are appropriately selected to drive the piezoelectric transformer 2 without using the secondary side electric wire. The present invention has been made based on the finding that the discharge lamp La can be lit by doing so. In the present embodiment, a luminous flux equivalent to an output of 1.5 W was obtained.

Regarding such a phenomenon, the inventor of the present application states that
As shown in FIG. 3, an equivalent circuit is assumed. In the figure, Cp1 is a primary parallel capacitor, which forms a main element of resonance together with the inductor L in the drive circuit. Ls is a series equivalent inductor, Cs is a series equivalent capacitor, and R is a series equivalent resistance. The impedance of these three elements constitutes a current limiting element for the discharge lamp La. Also, T0
Is a portion of the piezoelectric transformer 2 as an ideal transformer in performing the electro-mechanical-electrical conversion, and Cp2 is a capacitor existing in parallel on the secondary side, which is not clear here but is distributed. Then, it is presumed that the power transmission between the piezoelectric transformer 2 and the discharge lamp La is caused by a distributed capacity (capacitor). That is, when the discharge lamp La and the piezoelectric transformer 2 are brought into close contact with each other, there is a distribution capacitance between them in terms of structure, so that it is considered that a current flows through the distribution capacitance.

With this configuration, in the discharge lamp lighting device according to the present embodiment, the piezoelectric transformer 2 is used as the transformer that performs the step-up function. The size of the transformer can be reduced, and the discharge lamp lighting device can be reduced in size. In addition, an external connection which is a secondary-side electric wire between the secondary side, which is the power generation unit 4 of the piezoelectric transformer 2, and the discharge lamp La. Since no wires are needed,
There is no wiring to which a high voltage is applied, and there is no risk of secondary side short circuit, and there is no possibility that the piezoelectric transformer 2 will be broken. Further, since the piezoelectric transformer 2 is operated near the resonance frequency, the boosting ratio can be increased. Further, since the discharge lamp La does not emit light from the electrodes to emit light, no electrodes are required and the discharge lamp La has a long life. Further, since the piezoelectric transformer 2 has a small thickness, the discharge lamp L
By arranging “a” and the longitudinal direction thereof to coincide with each other, it is possible to contribute to a reduction in the thickness of the lighting device itself even when used in the lighting device.

FIG. 4 shows a discharge lamp lighting device according to a second embodiment of the present invention. The difference from the first embodiment is that an insulation between the piezoelectric transformer 2 and the discharge lamp La is provided. The configuration is the same as that of the first embodiment except that a resin reflecting plate 7 having a thickness of 0.7 mm and having properties is interposed. When the discharge lamp La was turned on by such a discharge lamp lighting device, a lighting light flux of 1.2 W was obtained.

Even with this configuration, the same effects as those of the first embodiment can be obtained, and there is no charged portion exposed when the discharge lamp La is replaced, so that the safety is improved and the lighting device reflects light. Compared to the case where the plate 7 is separately provided, it is possible to contribute to a reduction in thickness of the lighting device.

In this embodiment, if the piezoelectric transformer 2 and its drive circuit 5 are covered with an insulating resin, the discharge lamp can be safely located in a place with high humidity or in contact with water. A lighting device can be used.

FIG. 5 shows a third embodiment of the discharge lamp lighting device according to the present invention. The difference from the first embodiment is that the discharge lamp La is a U-shaped tube having a U-shape. In the space between the U-shaped discharge lamp La, the piezoelectric transformer 2 formed in a thin plate shape, the drive unit 3 is set to the U-shaped opening side, and the tube of the discharge lamp La faces the front and back surfaces. The other configuration is the same as that of the first embodiment. Even with this configuration, the discharge lamp La is
Even in the case of a U-shape, the same effect as in the first embodiment can be obtained, and the space between the U-shaped tubes in the U-shape can be used to provide a lighting device. In addition, it can further contribute to downsizing of the lighting device.

FIG. 6 shows a fourth embodiment of the discharge lamp lighting device according to the present invention. The difference from the first embodiment is that the discharge lamp La has a substantially thin outer shape. The discharge path is formed vertically and horizontally in a thin plate-like plane, for example, as a single discharge path so as to form a spiral or wavy shape, and the light emitting portion is formed so as to be substantially planar. The transformer 2 is formed in a planar shape having substantially the same area as the discharge lamp La, and a drive electrode 3a is formed on a side wall of the planar piezoelectric transformer 2 so that the planar discharge lamp La is piezoelectrically driven in a width-length mode. The second embodiment is the same as the first embodiment except that the transformer 2 is turned on. Even with such a configuration, the same effects as those of the first embodiment can be obtained even when the discharge lamp La is planar.

FIG. 7 shows a fifth embodiment of the discharge lamp lighting apparatus according to the present invention. The difference from the first embodiment is that the driving electrode 3a of the piezoelectric transformer 2 is replaced with the piezoelectric transformer 2 The drive unit 3 is formed by forming the drive unit 3 on both the front and back surfaces of the substantially central portion in the longitudinal direction, and the both ends are formed into a power generation unit 4 that generates a high voltage, and both ends are substantially aligned on the piezoelectric transformer 2. This is the point that the discharge lamp La is provided.
The configuration is the same as that of the embodiment. Even with such a configuration, the same effects as those of the first embodiment can be obtained, and both ends of the discharge lamp La have a high pressure and a central portion has a low pressure. Disappears.

FIG. 8 shows a sixth embodiment of the discharge lamp lighting device according to the present invention. The difference from the first embodiment is that the driving electrode 3a of the piezoelectric transformer 2 is The piezoelectric transformer 2 is driven in the width-length mode by setting the polarization direction of the driving unit 3 to the width direction, and the both ends of the piezoelectric transformer 2 are almost aligned on the piezoelectric transformer 2. The difference is that an electric lamp La is provided, and the rest is configured similarly to the first embodiment. Even with such a configuration, the same effects as those of the first embodiment can be obtained, and the connection of the external connection line 6 for connecting the drive electrode 3a and the drive circuit 5 is connected to the side where the discharge lamp La is in close contact. Since the connection can be made on different surfaces, the connection and the piezoelectric transformer 2 of the discharge lamp La
It can be easily arranged close to.

FIG. 9 shows a seventh embodiment of the discharge lamp lighting device according to the present invention. The difference from the first embodiment is that the piezoelectric transformer 2 is connected to one discharge lamp La. A plurality of discharge lamps L such that their ends on the power generation unit 4 side face each other with a predetermined interval therebetween.
a is turned on, and the other configuration is the same as that of the first embodiment.

In general, the transmission power and capacity of a piezoelectric transformer depend on the element shape of the piezoelectric transformer, and it is necessary to increase the element shape in order to obtain a large transmission power. However, since the ceramic is a sintered body and has a large shape, it is difficult to control the sintering process, and the yield and productivity are deteriorated.

The inventor of the present application attempted to transmit power from a plurality of piezoelectric transformers 2 to one discharge lamp La, and obtained the following favorable results. That is, the piezoelectric transformer 2 is formed in an elongated plate shape having a thickness of 2 mm, a width of 8 mm, and a length of 110 mm, and the drive electrodes 3 a are formed on both front and rear surfaces at one end. Then, the piezoelectric transformers 2 are arranged in the longitudinal direction of the discharge lamp La having a tube diameter of 4 mm and a length of 220 mm so that the drive electrodes 3a are positioned at both ends thereof. Are driven by applying a high-frequency voltage to them.
A lighting beam equivalent to W was obtained.

With this structure, the same effects as those of the first embodiment can be obtained, and a high output can be achieved by using a plurality of piezoelectric transformers 2.
In order to increase the output, the yield and productivity at the time of manufacturing the piezoelectric transformer 2 do not decrease.

FIG. 10 shows an eighth embodiment of the discharge lamp lighting device according to the present invention.
This embodiment is different from the first embodiment in that the discharge lamp La is replaced by the piezoelectric transformer 2 and the discharge lamp La.
By changing the distance d in the direction substantially perpendicular to the piezoelectric transformer 2 between the piezoelectric transformer 2 and the end of the discharge lamp La having substantially the same length as the piezoelectric transformer 2 so as to protrude from the end of the piezoelectric transformer 2. Some distance w in the direction parallel to the piezoelectric transformer 2
Is changed so that dimming can be controlled. The other configuration is the same as that of the first embodiment. Even with such a configuration, the same effect as that of the first embodiment can be obtained, and only the distance d between the piezoelectric transformer 2 and the discharge lamp in the substantially vertical direction with respect to the piezoelectric transformer 2 is changed, or The dimming control of the discharge lamp La can be performed only by changing the distance w in the direction parallel to the piezoelectric transformer 2 which is a dimension protruding from the end of the piezoelectric transformer 2 at the end of the discharge lamp La.

FIGS. 11 and 12 show a ninth embodiment of the discharge lamp lighting device according to the present invention. This discharge lamp lighting device comprises a piezoelectric transformer 2, a drive circuit 5 for the piezoelectric transformer 2, and a ballast 8 The high-pressure discharge lamp (high-intensity discharge lamp), which is the discharge lamp La, is started by the piezoelectric transformer 2 and is stably turned on by the ballast 8 after the start.

According to the equivalent circuit of the first embodiment, when the discharge lamp La is not connected, the piezoelectric transformer 2 has the largest boosting ratio, and the voltage is 10 times or more the voltage when the discharge lamp La is lit, for example. A voltage of 1 kV or more can be obtained. Therefore, here, the discharge lamp La is a metal halide lamp, which is a high-pressure discharge lamp, and the piezoelectric transformer 2 is disposed close to the arc tube 10 housed in the outer tube 9 so as to be separated by 1 mm. A startable voltage is applied to the electric lamp La. The piezoelectric transformer 2 has a thickness of 15 mm, a width of 3 mm, and a length of 30 mm, and operates in a thickness-length vibration mode when a drive electrode 3a at one end is connected to a drive circuit 5.

The drive circuit 5 is connected to the non-power supply side of the ballast 8 connected to the commercial power supply AC.
C2, a triac Tr, a current limiting inductor L0, and a pulse transformer PT. Then, when the power supply voltage rises and the voltage dividing capacitor C2 accumulates electric charge and the triac Tr turns on, a voltage is applied to the primary side of the piezoelectric transformer 2 via the pulse transformer PT, and the piezoelectric transformer 2 is driven. The secondary of the piezoelectric transformer 2 generates a transiently high voltage, and the arc tube 10
The discharge lamp La is started by applying a high voltage to the gas in the chamber continuously or in a pulsed manner. Once started, the discharge lamp La is supplied with electric power from the commercial power supply AC via the ballast 8, and is kept lit.

The piezoelectric transformer 2 has a relatively low Curie point. Above this Curie point, no piezoelectric / electrostrictive phenomenon occurs and the piezoelectric transformer 2 does not function as a transformer. In the material of this embodiment, the Curie point is about 300 ° C.
When the light-emitting tube 10 of the high-pressure discharge lamp, which is the discharge lamp La, is turned on, the tube wall temperature rises, and even at a position about 1 mm away, 800 ° C.
The temperature is about the same.
Generates a high voltage after the temperature drops below the Curie point.

With such a configuration, in the discharge lamp lighting device according to the present embodiment, the piezoelectric transformer 2 constituting the discharge lamp lighting device is arranged close to the light emitting tube 10 in the outer tube 9 of the discharge lamp La. Since the discharge lamp lighting device outside the outer tube 9 can be downsized, and no external connection line is connected to the power generation unit 4 side, which is the secondary side of the piezoelectric transformer 2,
There is no possibility that the secondary side of the piezoelectric transformer is short-circuited. Furthermore, since the starting voltage is generated by the piezoelectric transformer 2 disposed in proximity to the arc tube 10 of the discharge lamp La to start the discharge lamp La, no high pressure is generated outside the outer tube 9 of the discharge lamp La, and the safety is improved. The performance is improved. The discharge lamp La has a high mercury vapor pressure when the temperature is high immediately after the lamp is turned off and requires a high voltage that is ten times or more higher than that at normal temperature for starting.
Does not function as a transformer above the Curie point, operates after the temperature drops, the vapor pressure decreases, and the voltage required for starting decreases, so that unnecessary pulses are not generated.

FIGS. 13 and 14 show a discharge lamp lighting apparatus according to a tenth embodiment of the present invention. This discharge lamp lighting apparatus differs from the ninth embodiment in that The point is that the arc tube 10 itself of La is a ceramic arc tube made of a piezoelectric material, and the arc tube 10 and the piezoelectric transformer 2 are integrally formed. The other components are the same as those of the ninth embodiment. ing.

The arc tube 10 as the piezoelectric transformer 2 is a ceramic arc tube made of a piezoelectric material as described above.
Electrodes are provided at both ends of the inside of the cylindrical portion in which the discharge gas is sealed. One of the electrodes has a substantially columnar shape at one end on the side of the one electrode, and also serves as one drive electrode 3a with its substantially central axis at the center. Is formed, and a driving section 3 having the other of the driving electrodes 3a provided on the outer periphery is formed. This drive unit 3
Is polarized in the direction connecting one drive electrode 3a, which is the radial direction, and the other drive electrode 3a on the outer periphery, as indicated by an arrow A in FIG. As indicated by the arrow B, the power generation section 4 is polarized in the length direction. When a pulse or a high-frequency voltage is applied from the drive circuit 5 between the pair of drive electrodes 3a of the drive unit 3, a diameter-length vibration is generated, and a high voltage is generated in the length direction. As a result, the sealed gas near the tube wall breaks over and discharge starts. After the start of the discharge, electric power is supplied from the outside between the electrodes at both ends of the cylindrical portion.

With this configuration, in the discharge lamp lighting device according to the present embodiment, in addition to the effects of the ninth embodiment, the piezoelectric transformer 2 is connected to the arc tube 10.
The structure can be extremely simplified by integrating with, and the reliability and the workability of manufacturing are improved.

[0046]

According to the first aspect of the present invention, since the transformer which performs the step-up function is a piezoelectric transformer, magnetic saturation of the iron core and insulation of the winding are achieved. The transformer can be reduced in size without the need for design, etc., and the discharge lamp lighting device can be reduced in size. In addition, the external connection which is the secondary side electric wire between the secondary side, which is the power generation unit of the piezoelectric transformer, and the discharge lamp Since no wires are required, there is no longer any wiring to which high voltage is applied, and there is no danger of secondary side short circuit.
There is no possibility that the piezoelectric transformer will be broken.

According to the second aspect of the present invention, there is provided the first aspect.
In addition to the effects of the described invention, since the piezoelectric transformer is operated near the resonance frequency, the step-up ratio can be increased.

According to the third aspect of the invention, in addition to the effects of the first or second aspect, the discharge lamp can be lit without emitting electrons from the electrodes.
The discharge lamp has a long life.

According to the invention set forth in claim 4, claim 3
In addition to the effects of the described invention, the piezoelectric transformer has a small thickness, and is disposed so that the discharge lamp and the longitudinal direction thereof are aligned with each other. Can contribute to

According to the fifth aspect of the present invention, there is provided the third aspect.
In addition to the effects of the invention described above, by utilizing the space between the U-shaped discharge lamps, it is possible to further contribute to downsizing of the lighting device when used in a lighting device.

In the invention according to claim 6, claim 3
In addition to the effects of the described invention, high output can be achieved by using a plurality of piezoelectric transformers, and in order to increase the output, the yield and productivity during the manufacture of the piezoelectric transformer do not decrease. .

In the invention according to claim 7, claim 3
In addition to the effects of the described invention, the discharge lamp can be dimmed only by changing the distance between the piezoelectric transformer and the discharge lamp.

According to the eighth and ninth aspects of the present invention, in addition to the effects of the first aspect, the starting voltage is reduced by the piezoelectric transformer disposed close to the arc tube in the outer bulb of the discharge lamp. Since the discharge lamp is generated to start the discharge lamp, no high pressure is generated outside the outer tube of the discharge lamp, and the safety is improved. In addition, the discharge lamp La has a high mercury vapor pressure when the temperature is high immediately after the lamp is turned off, and requires a high voltage 10 times or more as compared with that at normal temperature for starting. It does not function and operates after the temperature has dropped and the vapor pressure has dropped, and the voltage required for starting has dropped, so that unnecessary pulses are not generated.

According to the tenth aspect, in addition to the effect of the eighth aspect, the structure can be extremely simplified by integrating the piezoelectric transformer with the arc tube.
Reliability and manufacturing workability are improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a different schematic view of the above.

FIG. 3 is an equivalent circuit diagram of the above.

FIG. 4 is a perspective view of a main part of a discharge lamp lighting device according to a second embodiment of the present invention.

FIGS. 5A and 5B show a main part of a discharge lamp lighting device according to a third embodiment of the present invention, wherein FIG. 5A is a front view and FIG. 5B is a side view.

FIG. 6 is a perspective view of a main part of a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view of a main part of a discharge lamp lighting device according to a fifth embodiment of the present invention.

FIG. 8 is a perspective view of a main part of a discharge lamp lighting device according to a sixth embodiment of the present invention.

FIG. 9 is a perspective view of a main part of a discharge lamp lighting device according to a seventh embodiment of the present invention.

10A and 10B show an eighth embodiment of the discharge lamp lighting device of the present invention, wherein FIG. 10A is a front view of a main part, and FIG. 10B is a diagram showing the relationship between d, w and light output in FIG. FIG.

FIG. 11 is a schematic diagram showing a ninth embodiment of the discharge lamp lighting device of the present invention.

FIG. 12 is an equivalent circuit diagram of the above.

FIG. 13 is a perspective view of a main part of a discharge lamp lighting device according to a tenth embodiment of the present invention.

FIG. 14 is a sectional view of the above.

FIG. 15 is a circuit diagram showing a conventional discharge lamp lighting device (first conventional example).

FIG. 16 shows another conventional discharge lamp lighting device (second conventional example).
FIG.

FIG. 17 is a circuit diagram showing still another conventional discharge lamp lighting device (third conventional example).

[Explanation of symbols]

 Reference Signs List 2 piezoelectric transformer 3 drive unit 4 power generation unit 5 drive circuit 6 external connection line 10 arc tube La discharge lamp

Claims (10)

[Claims] 1. A discharge lamp lighting device comprising: a discharge lamp; and a piezoelectric transformer for transmitting a power to the discharge lamp by generating a high voltage in a power generation unit by applying an AC voltage to a drive unit. An external connection line is connected to only the drive unit, and the discharge lamp is disposed in proximity to the power generation unit at least partially so as to transmit power from the power generation unit to the discharge lamp. Discharge lamp lighting device. 2. The piezoelectric transformer according to claim 1, wherein a driving circuit that oscillates near a resonance frequency of the piezoelectric transformer is connected to a driving section of the piezoelectric transformer, and the piezoelectric transformer is operated near the resonance frequency. 2. The discharge lamp lighting device according to 1. 3. The discharge lamp lighting device according to claim 1, wherein lighting of the discharge lamp is maintained by electric power transmitted from the piezoelectric transformer. 4. The piezoelectric transformer is formed in a thin plate shape, and the discharge lamp is formed in a straight tube, and the discharge lamp is disposed substantially parallel to a direction connecting the driving unit and the power generation unit of the piezoelectric transformer. The discharge lamp lighting device according to claim 3, wherein: 5. The method according to claim 5, wherein the piezoelectric transformer is formed in a thin plate shape, and the discharge lamp is a discharge lamp having a U-shape, and the piezoelectric transformer is disposed in a space between the discharge lamps in a U-shape. The discharge lamp lighting device according to claim 3, wherein: 6. The discharge lamp lighting device according to claim 3, wherein a plurality of said piezoelectric transformers are arranged close to said discharge lamp. 7. The discharge lamp lighting device according to claim 3, wherein the discharge lamp is dimmed by changing a distance between the piezoelectric transformer and the discharge lamp. 8. The discharge lamp lighting device according to claim 1, wherein the discharge lamp is started by electric power transmitted from the piezoelectric transformer. 9. The discharge lamp lighting device according to claim 8, wherein said discharge lamp is a high-pressure discharge lamp, and said piezoelectric transformer is disposed in close proximity to said arc tube. 10. The discharge lamp lighting device according to claim 8, wherein the discharge lamp is a high-pressure discharge lamp, and the arc tube is a piezoelectric transformer formed of piezoelectric ceramic and one end of which is a driving unit. .