JPH09320339A - Lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small size, as well as to receive hardly the influence of a noise to a control circuit, and to generate hardly a flicker to a discharge lamp. SOLUTION: This system is composed by providing a lamp body 2 furnishing a socket 2a to install a discharge lamp 1, and an lighting device 5 to light the discharge lamp 1. While the lighting device 5 is composed by providing a high-frequency circuit 7, and a piezoelectric transformer 11 excited and driven by the high-frequency wave of the high-frequency circuit 7, and to apply a high voltage to the discharge lamp 1, the piezoelectric transformer 11 is housed at the front end side of an arm 3 to support the lamp body 2 by approaching to the lamp body 2, in order to make the secondary side wire 5b to connect between the piezoelectric transformer 11 and the socket 2a, shorter that the primary side wire 5a to connect between the high-frequency circuit 7 and the piezoelectric transformer 11, and the high-frequency circuit 7 is housed in a base 4 provided on the base side of the arm 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device,
In particular, the present invention relates to an illuminating device that lights up a discharge lamp by boosting the output of a high frequency circuit section with a piezoelectric transformer.

[0002]

2. Description of the Related Art In general, a discharge lamp such as a cold cathode lamp or a neon tube does not require preheating for starting, but it requires a high voltage of several kV or more, and therefore such a discharge lamp is turned on. For the lighting device, a transformer is used so that a high voltage can be applied to the discharge lamp. The cold cathode lamp has been widely used as a backlight of a liquid crystal display, an evacuation guide light, a desk stand, or the like, and the neon tube has been widely used as a stop lamp or the like for automobiles. Further, in recent years, along with the miniaturization of such a lighting device, there has been a demand for a lighting device housed in the lighting device to be compact and thin.

FIG. 12 and FIG. 13 show a conventional lighting device, which is a desk stand and includes a lamp unit 2 for accommodating a discharge lamp 1 and a lamp unit 2. The arm 3 for supporting, the base 4 provided on the side of the arm 3 opposite to the lamp body 2, and the lighting device 5 for lighting the discharge lamp 1 are configured.

The base 4 has a box shape having a predetermined thickness and a space inside, and the base side of the long arm 3 is fixed to the upper surface of the base 4 so as to be substantially vertical. 1 is provided with a socket 2a for mounting a cold cathode lamp, which is the discharge lamp 1, and a lamp body 2 having a shade 2b provided so as to substantially cover the discharge lamp 1.

The lighting device 5 is connected to a direct-current voltage source 6 and includes a high-frequency circuit part 7 including a control circuit part 7a of a switching circuit for converting direct current into a high frequency, and a high voltage by increasing an output voltage of the high-frequency circuit part 7. And a high frequency transformer 8 for applying the high voltage to the discharge lamp 1.
Further, the high frequency transformer 8 is provided with a protection element 9 which is provided in the vicinity of the winding and operates when the abnormal temperature of the high frequency transformer 8 rises to operate due to the abnormal temperature and prevent the generation of smoke or the like.

The DC voltage source 6 is adapted to rectify a commercial power source to obtain DC, and the high frequency transformer 8 is
An electromagnetic conversion type transformer is used. The high-frequency transformer 8 has its primary side electrode connected to the high-frequency circuit section 7 by the primary-side electric wire 5a and is housed in the base 4 together with the high-frequency circuit section 7. The sockets 2a of the body portion 2 are connected by a secondary-side electric wire 5b passing through the long arm 3. Therefore, the secondary side electric wire 5b is made longer than the primary side electric wire 5a. In FIG. 1, 10 is
The switch provided in the base 4 for making a lighting device blink-operate is shown.

[0007]

However, in the conventional lighting device having such a configuration, the high frequency circuit section 7 and the high frequency transformer 8 are accommodated in the base 4 and are in close proximity to each other, and the high frequency transformer 8 is Since a high voltage of several kV is generated when the discharge lamp 1 is started, there is a problem that the control circuit section 7a of the high frequency circuit section 7 may be affected by noise and malfunction. Further, in order to prevent malfunction due to the influence of this noise, it is necessary to provide a protection circuit, which increases the number of parts of the lighting device 5, and the electromagnetic conversion type high frequency transformer 8 ensures a predetermined withstand voltage. However, the size of the lighting device 5 is inevitably large, and the protective element 9 is also required in order to ensure safety, and the lighting device 5 becomes large.

A high voltage applied to the discharge lamp 1 is also applied to the secondary side electric wire 5b between the high frequency transformer 8 and the socket 2a. If the secondary side electric wire 5b is long, the wiring capacity becomes large. As a result, the voltage drop becomes large, and a predetermined voltage may not be applied to the discharge lamp 1 mounted in the socket 2a. In addition, in order to apply a predetermined voltage to the discharge lamp 1, it is necessary to increase the step-up ratio of the high frequency transformer 8 by the amount of the voltage drop, and the high frequency transformer 8 becomes large and the efficiency deteriorates. If 5b is long, there is also a problem that noise is easily emitted to the outside.

Therefore, it is conceivable to house the lighting device 5 including the high frequency transformer 8 from the high frequency circuit part 7 in the lamp body part 2. However, in this lighting device, the high frequency circuit part 7 and the high frequency transformer 8 are close to each other. In addition to the problem that the control circuit portion 7a is easily affected by noise, there is a problem that the lamp body portion 2 becomes large and the appearance thereof becomes poor.

Further, as shown in FIG. 14, only the high frequency transformer 8 of the lighting device 5 is accommodated in the lamp body portion 2, the high frequency circuit portion 7 is accommodated in the base 4, and the secondary side electric wire 5 is accommodated.
It is also conceivable to make b shorter than the primary side electric wire 5a. However, in this lighting device, the secondary side electric wire 5b
Although the length of the coil is shortened and the emission of noise to the outside is suppressed, the primary side electric wire 5a between the high frequency circuit section 7 and the high frequency transformer 8 is lengthened, and this serves as an antenna and acts from the outside. However, since the output of the high-frequency transformer 8 is likely to be unstable and the lamp current of the discharge lamp 1 is as small as several mA, the discharge lamp 1 tends to flicker. Further, in order to prevent this, it is necessary to provide a filter in the high frequency transformer 8 so as to prevent noise from being transmitted. Therefore, there is a problem that the high frequency transformer 8 becomes large in size.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a miniaturized lighting device in which the control circuit portion is less susceptible to noise and the discharge lamp does not flicker. To do.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a lamp unit 2 provided with a socket 2a in which a discharge lamp 1 is mounted. ,
In a lighting device comprising a lighting device 5 for lighting the discharge lamp 1, the lighting device 5 is replaced by a high-frequency circuit unit 7.
And a piezoelectric transformer 11 which is excited and driven by the high frequency of the high frequency circuit section 7 to apply a high voltage to the discharge lamp 1.
And a secondary-side electric wire 5b for connecting between the piezoelectric transformer 11 and a terminal of the socket 2a that abuts on the discharge lamp 1, and a secondary electric wire 5b between the high-frequency circuit section 7 and the piezoelectric transformer 11. The high-frequency circuit section 7 and the piezoelectric transformer 11 are arranged so as to be shorter than the primary-side electric wire 5a connecting between them.

According to the second aspect of the present invention, the first aspect is provided.
In the lighting device described above, the piezoelectric transformer 11 is housed in an arm 3 supporting the lamp body portion 2 in the vicinity of the lamp body portion 2.

According to the invention of claim 3, claim 1
In the lighting device described above, the piezoelectric transformer 11 is housed in the lamp body portion 2.

According to the invention of claim 4, claim 3
In the lighting device described above, the piezoelectric transformer 11 is housed in the socket 2a.

According to a fifth aspect of the present invention, in the lighting device according to one of the first to fourth aspects, a feedback circuit 5c is provided between the piezoelectric transformer 11 and the high frequency circuit section 7. Is provided, and a part of the output from the piezoelectric transformer 11 is detected and fed back to the high frequency circuit section 7 to stabilize the lighting frequency of the discharge lamp 1.

According to a sixth aspect of the present invention, in the lighting device according to one of the first to fourth aspects, the low voltage side of the output portion of the piezoelectric transformer 11 and the discharge lamp 1 are provided. A detection resistor 12 for detecting a lamp current flowing in the discharge lamp 1 is inserted between them, and a feedback circuit 5c is provided between the detection resistor 12 side of the discharge lamp 1 and the high-frequency circuit section 7 to provide the discharge lamp. It is characterized in that the lamp current at the time of lighting 1 is stabilized.

[0018]

1 to 5 show a first embodiment of an illuminating device according to the present invention. This illuminating device is a desk stand and has a single-ended or double-ended type. Lamp unit 2 in which the discharge lamp 1 is housed, an arm 3 that supports the lamp unit 2, a base 4 provided on the opposite side of the arm 3 from the lamp unit 2, and the discharge lamp 1 are turned on. And a lighting device 5 for

The base 4 has a substantially plate-like shape and has a predetermined weight and is placed on a desk or the like.
The base side of the arm 3 which is long and has a space inside is fixed substantially vertically. Also, on the tip side of the arm 3,
A socket 2a for mounting a cold cathode lamp, which is a discharge lamp 1, is housed, and a lamp body portion 2 having a shade 2b provided so as to substantially cover the discharge lamp 1 is provided.
A switch 10 for blinking the lighting device is provided on the front upper surface of the base 4.

The arm 3 comprises a lower arm 3a fixed substantially vertically to the upper surface of the back side of the base 4 and an upper arm 3b rotatably provided on the upper side of the lower arm 3a. Spaces are provided inside the upper arm 3b and the upper arm 3b. The lamp body 2 is rotatably attached to the upper end of the upper arm 3b.

The lighting device 5 includes a high frequency circuit section 7 including a switching circuit and its control circuit section 7a, and a high frequency circuit section 7
And a piezoelectric transformer 11 for applying the high voltage to the discharge lamp 1, and the high-frequency circuit section 7 is a base of the lower arm 3a which is the base side of the arm 3. The piezoelectric transformer 11 is housed on the lamp body 2 side of the upper arm 3b, which is the tip side of the arm 3. The high frequency circuit section 7 is connected to a DC voltage source 6 obtained by rectifying a commercial power source, for example, and switches a switching circuit to convert DC into a high frequency. Therefore, the secondary-side electric wire 5b, which is a wire between the secondary-side electrode of the piezoelectric transformer 11 and the terminal of the socket 2a of the lamp body 2 that abuts the discharge lamp 1, is connected to the primary-side electrode of the piezoelectric transformer 11 and the high-frequency circuit. The wiring length is shorter than that of the primary side electric wire 5a which is a wiring between the portion 7 and the portion 7.
3 is a perspective view of the piezoelectric transformer 11 shown in FIG.
Shows the circuit diagram, and the piezoelectric transformer 11 is a Rosen type, and the shape is approximately 1.5 mm in thickness, 5 mm in width, and 5 in length.
It is formed to 0 mm.

In the lighting device configured as described above, in order to check the starting performance, the frequency is changed without the discharge lamp 1 being mounted in the socket 2a, the input / output voltage of the piezoelectric transformer 11 is measured, and the step-up ratio is measured. When (Vout / Vin) is examined, as shown by the curve A in FIG. 5, the frequency is 70 kHz.
Then, the mechanical resonance of the piezoelectric transformer 11 peaked, and the boost ratio was 100 times or more. Also, the frequency is 68k
It was found that in the range of Hz to 72 kHz, the step-up ratio is 20 times or more, and even if the input voltage Vin is about 60 V, a sufficient voltage can be obtained to start the cold cathode lamp which is the discharge lamp 1. Next, when the cold cathode lamp which is the discharge lamp 1 was attached to the socket 2a and the high frequency circuit section 7 was oscillated in the same frequency range, the discharge lamp 1 was started, and when the frequency was set to 65 kHz, the lamp A stable rated lighting state with a voltage of 400 V and a lamp current of 5 mA was entered. Then, when the frequency was changed and the step-up ratio (Vout / Vin) was examined while the discharge lamp 1 was turned on, as shown by a curve B in FIG. 5, the frequency was 63 kHz and the piezoelectric transformer 11
Mechanical resonance peaked and the boost ratio was about 10 times. Further, it has been found that the piezoelectric transformer 11 particularly boosts the input voltage of the limited frequency, and hardly boosts the input of the other frequencies, both at the time of starting the discharge lamp 1 and at the time of lighting the discharge lamp 1.

With such a configuration, in the lighting device according to the present embodiment, the secondary side electric wire which is the wiring between the piezoelectric transformer 11 to which a high voltage is applied and the socket 2a of the lamp body 2 is provided. 5b can be shortened, and the secondary side electric wire 5b
Since the voltage drop at 2 can be reduced and the efficiency can be improved, and the loop of the secondary side electric wire 5b can be reduced, the emission of noise to the outside of the lighting device can be suppressed. Further, even if the primary side electric wire 5a, which is a wiring between the piezoelectric transformer 11 and the high frequency circuit unit 7, picks up noise, the piezoelectric transformer 11 boosts only a limited frequency component, so that the noise component is cut off. The discharge lamp 1 does not flicker. Furthermore, the piezoelectric transformer 11 is made of ceramics, does not require a protective element, and controls the high-frequency circuit unit 7 by the control circuit unit 7a.
However, since it is separated from the piezoelectric transformer 11 and the secondary side electric wire 5b reaching the socket 2a, the control circuit portion 7a is less likely to malfunction.

FIG. 6 and FIG. 7 show a second illumination device of the present invention.
The first embodiment is different from the first embodiment in that the piezoelectric transformer 11 of the lighting device 5 is connected to the discharge lamp 1
The lamp 2 is housed in the lamp body 2 in the vicinity of the socket 2a to which the lamp is mounted. The rest is configured similarly to the first embodiment.

That is, the piezoelectric transformer 11 is the end of the lamp body 2 fixed to the tip of the arm 3, for example, near the arm 3 side of the socket 2a, or the shade to which the light of the discharge lamp 1 is irradiated. It is arranged inside 2b or the like, and particularly when arranged inside the shade 2b, it is housed in a white case so as not to affect the light distribution.

Even with this structure, the same effect as that of the first embodiment can be obtained, and the piezoelectric transformer 11 and the socket 2a can be arranged closer to each other, and the wiring to which the high voltage is applied can be formed. Further, the voltage drop can be further reduced, the efficiency can be improved by further reducing the voltage drop, and the emission of noise to the outside of the lighting device can be further suppressed.

FIGS. 8 and 9 show a third embodiment of the illuminating device of the present invention. The difference from the first embodiment is that the piezoelectric transformer 11 of the lighting device 5 is released. It is accommodated in the socket 2a for mounting the electric lamp 1,
Otherwise, the configuration is the same as that of the first embodiment. In addition, in FIG. 9, (a) shows the case where the discharge lamp 1 is a double-ended die, and (b) shows the case where it is a single-ended die.

Even with this structure, the same effect as that of the first embodiment can be obtained, and the piezoelectric transformer 11 and the discharge lamp 1 can be arranged closer to each other, and the wiring to which the high voltage is applied. Can be further shortened, the voltage drop can be further reduced to improve efficiency, and the emission of noise to the outside of the lighting device can be further suppressed. Further, by housing the piezoelectric transformer 11 in the socket 2a, it is not necessary to form a housing part for the piezoelectric transformer 11 in the arm 3, and the number of parts can be reduced.

FIG. 10 shows a fourth embodiment of the illuminating device of the present invention. The difference from the first embodiment is that the piezoelectric transformer 11 is provided with a detection electrode on the side surface thereof. A feedback circuit 5c is provided between the detection electrode and the high frequency circuit section 7, and a part of the output is detected from the piezoelectric transformer 11 and is fed back to the high frequency circuit section 7 to stabilize the lighting frequency of the discharge lamp 1. The others are configured in the same manner as the first embodiment.

Even with this structure, the same effect as that of the first embodiment can be obtained, and the feedback circuit 5c allows
By returning a part of the output of the piezoelectric transformer 11 when the discharge lamp 1 is turned on to the control circuit section 7a of the high frequency circuit section 7,
The operating frequency can be stabilized.

FIG. 11 shows a fifth embodiment of the illuminating device of the present invention. The difference from the first embodiment is that the low voltage side of the output part of the piezoelectric transformer 11 and the discharge lamp 1 are different. In between, a detection resistor 1 for detecting the lamp current flowing through the discharge lamp 1
2 is provided, and a feedback circuit 5c is provided between the discharge lamp 1 side of the detection resistor 12 and the high frequency circuit section 7 so that the operating frequency at the time of lighting the discharge lamp 1 and the trigger signal of the switching element of the high frequency circuit section 7 The point is that the lamp current is stabilized by controlling the duty, and the other points are the same as those in the first embodiment.

Even with this structure, the same effect as that of the first embodiment can be obtained, and the feedback circuit 5c allows
The control circuit unit 7 of the high frequency circuit unit 7 controls the lamp current of the discharge lamp 1
By returning to a, the lamp current can be made constant.

In each of the above embodiments, the illuminating device is a desk stand provided with the base 4, and the high frequency circuit section 7 is housed in the arm 4 on the side of the base 4 as an example. The present invention is not limited to this, and may be one in which a high-frequency circuit unit is housed in a base, or a desk stand without a base in which a mounting portion is provided at the lower end of an arm. The lighting device of FIG.

[0034]

As described above, according to the invention described in claim 1, the piezoelectric transformer to which a high voltage is applied and the terminal abutting against the discharge lamp of the socket of the lamp body are provided. The secondary wire, which is the wiring between the two, can be shortened, the voltage drop in the secondary wire can be reduced, and the efficiency can be improved. Can be suppressed. Further, even if the primary electric wire, which is the wiring between the piezoelectric transformer and the high frequency circuit unit, picks up noise, the piezoelectric transformer boosts only a limited frequency component, so the noise component is cut and the discharge lamp flickers. Nothing. Furthermore, since the piezoelectric transformer is made of ceramics, no protective element is required, and the control circuit section of the high-frequency circuit section is separated from the secondary-side electric wire leading to the piezoelectric transformer and the socket, the control circuit section malfunctions. It becomes difficult to wake up.

According to the invention of claim 2, claim 1
In addition to the effects of the invention described, the piezoelectric transformer can be housed on the side of the lamp body of the arm and can be arranged closer to the socket, and the wiring to which a high voltage is applied can be further shortened, and the voltage drop can be further reduced. As a result, the efficiency can be improved, and the emission of noise to the outside of the lighting device can be further suppressed.

In the invention according to claim 3, claim 1 is
In addition to the effects of the invention described, the piezoelectric transformer can be housed in the lamp body and arranged closer to the socket, the wiring to which a high voltage is applied can be further shortened, and the voltage drop can be further reduced to improve efficiency. And the emission of noise to the outside of the lighting device can be further suppressed.

According to the invention of claim 4, claim 3
In addition to the effects of the invention described, the piezoelectric transformer can be housed in the socket and arranged further close to the discharge lamp, and the wiring to which a high voltage is applied can be further shortened to further reduce the voltage drop and improve the efficiency. And the emission of noise to the outside of the lighting device can be further suppressed. Further, by accommodating the piezoelectric transformer in the socket, it is not necessary to form a piezoelectric transformer accommodating portion in the arm, and the number of parts can be reduced.

According to the invention described in claim 5, in addition to the effect of the invention described in any one of claims 1 to 4, a feedback circuit is provided to prevent the piezoelectric transformer from being turned on. The operating frequency can be stabilized by feeding back a part of the output to the control circuit section of the high frequency circuit section.

According to the invention of claim 6, in addition to the effect of the invention of one of claims 1 to 4, the feedback circuit changes the lamp current of the discharge lamp to a high-frequency circuit part. It is possible to make the lamp current constant by feeding back to the control circuit section of.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a lighting device of the present invention.

FIG. 2 is a schematic diagram including a circuit configuration of the above illumination device.

FIG. 3 is a perspective view showing a piezoelectric transformer of the same.

FIG. 4 is an equivalent circuit diagram of the above piezoelectric transformer.

FIG. 5 is a characteristic diagram showing a boost ratio of the same.

FIG. 6 is a perspective view showing a second embodiment of a lighting device of the present invention.

FIG. 7 is a schematic diagram including a circuit configuration of the above illumination device.

FIG. 8 is a perspective view showing a third embodiment of a lighting device of the present invention.

FIG. 9 is a view showing the main part of the above, wherein (a) is a schematic view of a socket when the discharge lamp has a double base, and (b) is a schematic view of a socket when the discharge lamp has a single base. .

FIG. 10 is a circuit configuration diagram showing a fourth embodiment of a lighting device of the present invention.

FIG. 11 is a circuit configuration diagram showing a fifth embodiment of a lighting device of the present invention.

FIG. 12 is a perspective view showing a conventional illumination device (first conventional example).

FIG. 13 is a schematic diagram including a circuit configuration of the above illumination device.

FIG. 14 is a different schematic diagram including the circuit configuration of the above illumination device.

[Explanation of symbols]

 1 Discharge Lamp 2 Lamp Body 2a Socket 3 Arm 5 Lighting Device 5a Primary Wire 5b Secondary Wire 5c Feedback Circuit 7 High Frequency Circuit 11 Piezoelectric Transformer 12 Detection Resistor

Claims (6)

[Claims] 1. A lighting device comprising a lamp body portion provided with a socket to which a discharge lamp is mounted, and a lighting device for lighting the discharge lamp, wherein the lighting device comprises a high-frequency circuit part and a high-frequency circuit part. A piezoelectric transformer that is excited and driven by a high frequency of a circuit section and applies a high voltage to the discharge lamp, and a secondary connecting between the piezoelectric transformer and a terminal of the socket that contacts the discharge lamp. An illumination device, wherein the high frequency circuit section and the piezoelectric transformer are arranged such that a side electric wire is shorter than a primary side electric wire connecting between the high frequency circuit section and the piezoelectric transformer. 2. The lighting device according to claim 1, wherein the piezoelectric transformer is housed in an arm that supports the lamp body portion in proximity to the lamp body portion. 3. The lighting device according to claim 1, wherein the piezoelectric transformer is housed in the lamp body portion. 4. The lighting device according to claim 3, wherein the piezoelectric transformer is housed in the socket. 5. A feedback circuit is provided between the piezoelectric transformer and the high-frequency circuit section, and a part of the output from the piezoelectric transformer is detected and fed back to the high-frequency circuit section to stabilize the lighting frequency of the discharge lamp. Claim 1, characterized in that
A lighting device according to one of claims 4 to 4. 6. A detection resistor for detecting a lamp current flowing through the discharge lamp is inserted between the low voltage side of the output portion of the piezoelectric transformer and the discharge lamp, and the discharge lamp side of the detection resistor and the high frequency circuit. 5. A lighting device according to claim 1, wherein a feedback circuit is provided between the parts to stabilize a lamp current when the discharge lamp is turned on.