JP2007281356A - Piezoelectric ceramic transformer apparatus and light source apparatus employing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe piezoelectric ceramic transformer apparatus which has no danger of smoking or ignition even if it is driven with high power and never causes damage of a piezoelectric ceramic transformer, and to provide a light source apparatus which is applicable to a planar illumination apparatus of a small/large liquid crystal display capable of allowing a discharge tube, especially, a plurality of discharge tubes to uniformly simultaneously illuminate. <P>SOLUTION: The ceramic transformer apparatus has a piezoelectric transformer for outputting a secondary side AC signal on the basis of a primary side AC signal inputted, a driving section for inputting the primary side AC signal into the piezoelectric ceramic transformer, a temperature detecting means for detecting the temperature of the piezoelectric ceramic transformer, and a protective circuit for limiting the input of the primary side AC signal by the driving section in response to the temperature detected by the temperature detecting means. The apparatus further has discharge tubes emitting a light on the basis of driving the piezoelectric transformer, a tube current detecting circuit for detecting the tube current flowing in the discharge tubes, and a voltage-controlled oscillation circuit for generating a basic wave of an oscillation frequency controlled corresponding to the tube current. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a piezoelectric ceramic transformer device and a light source device using the piezoelectric ceramic transformer, and more particularly, using a piezoelectric ceramic transformer, there is no risk of smoke or ignition even when high power (high power) driving is performed. A safe piezoelectric ceramic transformer device that does not cause damage to the light source device, and a light source device that can uniformly emit light with uniform current flowing in the discharge tube, in particular, uniform current flowing in a plurality of discharge tubes. The present invention relates to a light source device that can be applied as a planar illumination device for a small to large liquid crystal display device capable of simultaneously and uniformly emitting a plurality of discharge tubes.

Piezoelectric ceramic transformers using piezoelectric ceramics (hereinafter simply referred to as “piezoelectric transformers”) have disadvantages such as the inability to obtain large currents (high power) and the difficulty of frequency control during driving. Compared with this, there are many advantages such that the thickness can be reduced, the conversion efficiency is high, the insulation on the secondary side can be easily taken, the structure is simplified, and the step-up ratio can be increased.
For this reason, piezoelectric transformers were first put into practical use as piezoelectric inverters for small computers such as mobile computers. Conventional piezoelectric transformers have only a driving capacity of 2 to 3 W. Only one or two light sources can be illuminated, and its use has been limited to lighting a small cold cathode discharge tube of a backlight used in a liquid crystal display device of a special small computer.

By the way, when an abnormality occurs in a secondary side, that is, a load on the output side, for example, a cold cathode discharge tube, and the secondary side is in an abnormal state such as a short circuit (short), a large current is applied to the winding of the transformer. As a result of the flow, the temperature of the windings rises, the insulation of the windings melts, and finally, a short circuit between the windings may cause smoke or fire from the windings.
On the other hand, the piezoelectric transformer also has a thermal runaway when an abnormality occurs on the secondary side and the secondary side is in an abnormal state such as open or short-circuited. However, the piezoelectric transformer eventually breaks and is destroyed. No current flows on either side or secondary side. For this reason, even if an abnormality occurs and thermal runaway occurs, there is no risk of causing smoke or fire, or such a risk is rare, and a piezoelectric transformer is safer than a wound transformer There is an advantage.
As a result, piezoelectric inverters are now being used rapidly as inverters for relatively small computers.

In such a small output (low power) piezoelectric transformer, a piezoelectric transformer device has been proposed in which measures are taken to prevent the breakdown (see Patent Document 1).
In the piezoelectric transformer device disclosed in Patent Document 1, a low-power piezoelectric transformer element having a length of 30 mm, a width of 6 mm, and a thickness of about 1.9 mm is used to protect the piezoelectric transformer element from thermal runaway and damage. Instead of the resistance element used to maintain the primary impedance at a predetermined value, a positive temperature coefficient thermistor element whose resistance increases with increasing temperature is connected in series to the primary side of the piezoelectric transformer element. Even if the ambient temperature rises or the secondary side of the piezoelectric transformer element is opened or short-circuited and the primary side impedance decreases, the resistance of the thermistor element increases and the primary Since the increase in the side current can be suppressed, thermal runaway due to the increase in the primary current can be suppressed, and the piezoelectric transformer element is protected from thermal runaway and damage. You can do that.
Also, when resistance is not required at low temperatures such as ambient temperature, the resistance value of the thermistor element is small, so energy loss is reduced compared to the case of the above resistance element, and an efficient piezoelectric transformer. It can be a device.

Japanese Patent Laid-Open No. 10-321928

By the way, in the piezoelectric transformer device disclosed in Patent Document 1, since the thermistor is connected in series to the primary side of the piezoelectric transformer element, the resistance value of the thermistor increases in proportion to the temperature rise. Although it is possible to suppress a decrease in the secondary side impedance, suppress an increase in the primary side current, and protect the piezoelectric transformer element from thermal runaway or damage, the primary side current is not cut off, so the secondary side There is a problem that the primary current flows even in an abnormal state where the circuit is opened or short-circuited.
Further, in the piezoelectric transformer device disclosed in Patent Document 1, in the normal driving state where the ambient temperature is a low temperature such as normal temperature and does not require resistance, the resistance value of the thermistor element is smaller than that of the resistance element. There is a problem that there is energy loss because the resistance value is not without.

By the way, although high power (high power) of the piezoelectric transformer has been tried, conventionally, when the output exceeds 5 W, which is about twice, the relationship between the output and the temperature rise becomes non-linear. There are problems such as abnormal heat generation and cracking of the piezoelectric transformer element.
However, one of the present applicants, for example, by providing a rigid body portion made of an unpolarized portion at the central portion of a piezoelectric ceramic transformer made of piezoelectric ceramic, for example, length 63 mm × width 8 to 15 mm × thickness about 1.2 mm. Japanese Patent Application Laid-Open No. 2005-129475 proposes a high-efficiency, lightweight high-power (high power) piezoelectric transformer having an output of 5 W or more, preferably about 6 W to 30 W. In this piezoelectric transformer, the temperature rise at the time of high power (high power) driving around 15 W to 30 W can be saturated with a rise of about 10 ° C. to 20 ° C. from room temperature.
As described above, when the secondary side of the piezoelectric transformer is in an abnormal state such as an open circuit or a short circuit, the primary current is increased due to the decrease in the primary side impedance, the resulting thermal runaway or damage of the piezoelectric transformer, Problems such as energy loss in the driving state increase as the driving of the piezoelectric transformer becomes higher power.

  The object of the present invention is to solve the above-mentioned problems of the prior art, there is no risk of smoke or ignition even when high power (high power) driving is performed, and a safe piezoelectric that does not cause destruction of the piezoelectric ceramic transformer. A ceramic transformer device and a light source device using the ceramic transformer device to uniformly emit light with uniform current flowing in the discharge tube, and in particular, uniform current flowing in a plurality of discharge tubes to uniformly emit a plurality of discharge tubes simultaneously. It is an object of the present invention to provide a light source device that can be applied as a planar illumination device for a small to large liquid crystal display device.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a piezoelectric ceramic transformer that outputs a secondary AC signal based on an input primary AC signal, and the primary side of the piezoelectric ceramic transformer. A drive unit that inputs an AC signal, a temperature detection unit that detects the temperature of the piezoelectric ceramic transformer, and an output of the primary AC signal by the drive unit according to the temperature detected by the temperature detection unit. A piezoelectric ceramic transformer device having a protective circuit is provided.

The piezoelectric ceramic transformer further includes a holding member for the piezoelectric ceramic transformer, a base, and a fixing member for fixing the holding member to the base, and the piezoelectric ceramic transformer fixes the holding member to the base. It is preferable to fix to the said base by interposing between members.
In addition, the holding member is preferably an elastic material having a trapezoidal or substantially trapezoidal shape in the cross section of the holding member, and the elastic material is preferably a fixing rubber. .
The holding member preferably holds the position of the vibration node of the piezoelectric ceramic transformer.

The temperature detection means is preferably mounted on the piezoelectric ceramic transformer so as to be in direct contact between the piezoelectric ceramic transformer and the holding member, and further, the temperature detection means is the holding It is preferable that the member is embedded and held inside the member and attached so as to be in direct contact with the piezoelectric ceramic transformer.
Alternatively, it is preferable that each of the holding member and the fixing member is a heat conductive member, and the temperature detection unit is fixed on the fixing member.
Furthermore, the temperature detecting means is preferably a thermistor.

In order to achieve the above object, according to a second aspect of the present invention, there is provided a piezoelectric ceramic transformer device according to the first aspect and a discharge connected to an output side of the piezoelectric ceramic transformer and emitting light by driving the piezoelectric ceramic transformer. A light source device including a tube is provided.
Further, a tube current detection circuit for detecting a tube current flowing through the discharge tube when the discharge tube emits light, and a signal having an oscillation frequency controlled according to the tube current detected by the tube current detection circuit are generated. It is preferable to have a voltage controlled oscillation circuit.

Here, the discharge tube is a plurality of cold cathode discharge tubes, and the tube current detection circuit detects a total current of the tube currents flowing through the plurality of cold cathode discharge tubes emitting light. Is preferred.
Moreover, it is preferable that the light source device functions as a planar illumination device having a planar light exit surface.

Furthermore, it is preferable that the holding member is provided around the outer periphery of the piezoelectric ceramic transformer. Alternatively, the holding member is configured by two rod-shaped holding bodies arranged to face each other with the piezoelectric ceramic transformer interposed therebetween. Each holding body preferably extends linearly in any one of the length direction, the width direction and the thickness direction of the piezoelectric ceramic transformer. In this case, it is preferable that the holding body is formed using an elastic material having conductivity.
The base is preferably a substrate such as a printed circuit board or a flat plate. In this case, when the piezoelectric ceramic transformer (piezoelectric ceramic transformer assembly) provided with the holding member is fixed, the fixing member is in contact with the surface of the holding member opposite to the surface in contact with the piezoelectric ceramic transformer. A flat end, a pair of legs bent in substantially the same direction from both ends of the flat part, and a fixed end located at each end of the pair of legs and connected to the base It is preferable to have. Alternatively, the fixing member is an upper case in which a concave portion is formed, and all or part of the piezoelectric ceramic transformer (piezoelectric ceramic transformer assembly) provided with the holding member is accommodated in the concave portion of the upper case. Is preferred.

  Alternatively, the base is a lower case in which a recess is formed, and all or part of the piezoelectric ceramic transformer (piezoelectric ceramic transformer assembly) provided with the holding member is accommodated in the recess of the lower case. Is preferred. In this case, the fixing member is an upper case in which a recess is formed, and the side of the upper case where the recess is formed faces the side of the lower case where the recess is formed. And the lower case, the piezoelectric ceramic transformer (piezoelectric ceramic transformer assembly) provided with the holding member is housed in a space formed by the concave portion of the upper case and the concave portion of the lower case. It is preferable.

The piezoelectric ceramic transformer preferably includes a piezoelectric ceramic, an input electrode formed on the piezoelectric ceramic, and an output electrode formed on the piezoelectric ceramic.
Further, the piezoelectric ceramic includes one end portion in a longitudinal direction, a first region polarized in a direction toward the end portion, a first region adjacent to the first region and polarized in a thickness direction of the piezoelectric ceramic. 2 regions, adjacent to the second region, and located substantially in the center of the piezoelectric ceramic, unpolarized third region, adjacent to the third region, and polarized in the opposite direction to the second region The fourth region, and a fifth region adjacent to the fourth region and including an end opposite to the end and polarized in the opposite direction to the first region, A ratio of lengths of the first region, the second region, the third region, the fourth region, and the fifth region in the longitudinal direction is substantially 2: 2: 1: 2: 2, A pair of first input electrodes are provided across the second region, and a pair of second input electrodes are interposed across the fourth region. Electrodes are provided, it is preferable that the longitudinal direction of both the respective output electrodes to an end of the piezoelectric ceramic is provided.

  According to the piezoelectric ceramic transformer device of the first aspect of the present invention, since the surface temperature of the piezoelectric ceramic transformer can be detected and the system can be shut down based on the detected temperature, even if many protection circuits are unnecessary, The risk of smoking and ignition is eliminated, and the piezoelectric ceramic transformer can be safely driven, in particular, high power (high power) drive without causing destruction. Therefore, according to this aspect, by eliminating many protection circuits, the circuit scale can be reduced, and as a result, the cost can be reduced.

  Further, according to the light source device of the second aspect of the present invention, since the piezoelectric ceramic transformer device having the above effect is used, in addition to the above effect, the current flowing through the discharge tube is made uniform even in a small circuit scale. It is possible to emit light uniformly. Particularly, in the case of using a plurality of discharge tubes, the current flowing through the plurality of discharge tubes can be made uniform so that the plurality of discharge tubes can emit light simultaneously. It can be applied as a planar lighting device of the device.

  A piezoelectric ceramic transformer device according to a first aspect of the present invention and a light source device according to the second aspect of the present invention using the same will be described below in detail based on preferred embodiments shown in the accompanying drawings.

1A and 1B are a block diagram and a circuit block showing an outline of an embodiment of a light source device according to the second aspect of the present invention using the piezoelectric ceramic transformer device according to the first aspect of the present invention. It is explanatory drawing which shows a structure.
As shown in the figure, the light source device 10 of the present invention includes a power source 12, a drive unit 14, a piezoelectric ceramic transformer (hereinafter simply referred to as a piezoelectric transformer) 16, a light emitting unit 18, a tube current detection circuit 20, The drive unit 14 includes an oscillation unit 26 including a voltage-controlled oscillation circuit 24 and a drive circuit 30 including a protection circuit 28.
Here, the power supply 12, the drive unit 14, the piezoelectric transformer 16, and the temperature detection device 22 of the piezoelectric transformer 16 constitute a piezoelectric ceramic transformer device (hereinafter referred to as a piezoelectric transformer device) 11 of the present invention.

The power source 12 is a DC power source that outputs a DC voltage of 24V. This DC voltage DC24V is supplied to the drive circuit 14. Note that the DC voltage output from the power supply 12 is not limited to DV24V.
Subsequently, the drive unit 14 generates a drive signal for driving the piezoelectric transformer 16, that is, a primary AC signal input to the piezoelectric transformer 16.
The oscillating unit 26 of the driving unit 14 oscillates a clock (fundamental wave) having a predetermined frequency for generating a primary side AC signal, and includes a voltage controlled oscillation circuit 24.

Here, the voltage controlled oscillation circuit (VCO) 24 is a current value of a tube current of a discharge tube of the light emitting unit 18 supplied from the tube current detection circuit 20, for example, a cold cathode discharge tube (hereinafter simply referred to as a cold cathode tube). In response to this, an initial frequency whose oscillation frequency changes, for example, a fundamental wave of about 40 KHz is generated. For example, when the tube current is smaller than the reference current amount, the voltage controlled oscillation circuit 24 controls the fundamental wave frequency to be lower than the initial frequency, and conversely, when the tube current is larger than the reference current amount. In this case, the fundamental frequency is controlled to be higher than the initial frequency. This fundamental wave is also supplied to the drive circuit 30 of the drive unit 14.
The specific configurations of the oscillation unit 26 and the voltage controlled oscillation circuit 24 are not limited at all, and various configurations of circuits that realize the same function can be used. Further, the reference current amount can be controlled from the outside and can be varied as necessary.

  The drive circuit 30 of the drive unit 16 is a drive signal for driving the piezoelectric transformer 16 based on a DC voltage supplied from the power supply 12, for example, DC 24V, and a fundamental wave supplied from the voltage controlled oscillation circuit 24, that is, A primary AC signal is generated. The primary side AC signal input to the piezoelectric transformer 16 may be a single phase with one side grounded (GND). In the case of the present embodiment, the drive signal is, for example, an AC signal (sine wave) of about 650 Vp-p (peak to peak), about 40 KHz, and 180 degrees out of phase. The frequency of the drive signal changes according to the frequency of the fundamental wave supplied from the voltage controlled oscillation circuit 24, and controls the tube current of the light emitting unit 18, for example, the cold cathode tube, that is, the luminance of the light emitting unit 18.

Specifically, as shown in FIG. 1B, the drive circuit 30 includes a frequency dividing D-type flip-flop (D-FF) 30a, a waveform shaping unit 30b, a gate unit 30c constituting a protection circuit 28, and a drive. 30d is provided.
In the drive circuit 30, the D-FF 30 a divides the fundamental wave from the voltage controlled oscillation circuit 24, and the waveform shaping unit 30 b has a longer period (about approximately) than the divided fundamental wave and the fundamental wave that allows dimming. 100 to 200 Hz) is generated by multiplying the PWM wave. If the ON-DUTY of the PWM wave is wide, the ON period of the intermittent wave is increased, the average current flowing through the lamp is increased, and control can be performed in a brighter direction. Conversely, if the ON-DUTY of the PWM wave is narrow, it can be controlled in the darkening direction.

In the waveform shaping unit 30b, the drive wave generated by multiplying the fundamental wave and the PWM wave is injected into the drive circuit of the subsequent drive unit 30d through the gate circuit of the gate unit 30c. The gate circuit is a logic circuit for applying protection by the protection circuit 28. The gate circuit can be used in various abnormal modes such as opening (opening) or shorting (shorting) of the secondary load (for example, CCFL) of the piezoelectric transformer 16. Protect the system. Details of the protection mode by the protection circuit 28 will be described later.
Next, the drive signal that has passed through the gate portion 30c is injected into the drive portion 30d. As described above, the drive signal is generated into two signals having a phase difference of 180 degrees by the D-FF 30a in the previous stage, and then passes through the waveform shaping circuit of the waveform shaping unit 30b, respectively, and a low impedance load (for example, CCFL) ) Enters the drive unit 30d composed of a bridge circuit using FETs so that the circuit can be sufficiently driven. The purpose of the waveform shaping circuit is to prevent the upper FET and the lower FET of the bridge circuit from turning on at the same time and causing a through current to flow.

As shown in FIG. 1A, the protection circuit 28 included in the drive circuit 30 is configured such that the drive circuit 30 is detected when the detected temperature from the temperature detection device 22 of the piezoelectric transformer 16 exceeds a predetermined allowable upper limit value. To stop the output of the drive signal. That is, by providing the protection circuit 28, when any abnormality (for example, open or short circuit) occurs in the cold cathode tube or the like of the light emitting unit 18, the impedance on the primary side of the piezoelectric transformer 16 decreases, and the piezoelectric transformer 16 Current increases, the vibration of the piezoelectric transformer 16 increases, the temperature of the piezoelectric transformer 16 rises, and the temperature of the piezoelectric transformer 16 detected by the temperature detection device 22 exceeds the upper limit value of the predetermined allowable temperature. However, since the protection circuit 28 stops the drive signal of the piezoelectric transformer 16 at that time, the drive of the piezoelectric transformer 16 is stopped, the current stops flowing, and the vibration of the piezoelectric transformer 16 also stops. And can be prevented from being destroyed. Further, even when the thermal runaway of the piezoelectric transformer 16 occurs other than an abnormality of the light emitting unit 18, the piezoelectric transformer 16 can be prevented from being destroyed.
Note that specific circuit configurations of the drive circuit 30 and the protection circuit 28 are not limited at all, and various configurations of circuits that realize similar functions can be used. Further, in the protection circuit 28, the predetermined allowable upper limit value of the detected temperature from the temperature detecting device 22, that is, the upper limit value of the predetermined allowable temperature of the piezoelectric transformer 16 can be controlled from the outside and can be varied as necessary. it can.

For example, as shown in FIG. 1B, when a thermistor 58 is used as the temperature detection device 22 described later, the thermistor 58 detects the temperature of the piezoelectric transformer 16, and the resistance value changes according to the temperature. The change in the resistance value of the thermistor 58 changes the voltage value input to the comparator 28a of the protection circuit 28 by voltage division with the pull-up resistor R connected in series with the thermistor 58. The pull-up resistor R is disposed in the drive circuit 30, that is, on the input side of the comparator 28 a in the protection circuit 28.
The comparator 28a of the protection circuit 28 compares the input voltage value with the reference voltage value of the reference voltage source 28b, and if the thermistor 58 has a general negative characteristic, the input voltage corresponding to the measured temperature. When it is determined that the value is lower than the reference voltage value corresponding to the set threshold temperature, that is, the measured temperature is higher than the set threshold value, the comparator 28a issues an error signal. Since the output of the comparator 28a is connected to the gate unit 30c, the error signal output from the comparator 28a turns off the gate circuit of the gate unit 30c, and the waveform shaping unit 30b of the drive circuit 30 to the drive unit 30d. Cut off drive signal input. Thus, the system is shut down.

Thus, in the present invention, the temperature detection device 22 detects the temperature of the piezoelectric transformer 16, and the protection circuit 28 of the drive circuit 30 detects the drive signal to the drive unit 30 d of the drive circuit 30 according to the detected temperature. Since the input is cut off, the generation of the drive signal in the drive circuit 30 is stopped, and the system is shut down, for example, an overcurrent detection circuit and an overcurrent protection circuit in the drive unit 30d of the drive circuit 30 In addition, it is possible to reduce circuit portions such as an output voltage detection circuit on the output side of the piezoelectric transformer 16, a low voltage protection (short protection) circuit, and an overvoltage protection (open protection) circuit.
In addition, if it is a circuit part which has a function which prevents the piezoelectric transformer 16 from being destroyed by this invention, a reduction is possible and it is not limited to the said 2 circuit part.
Further, as described above, the temperature detection result by the temperature detection device 22 may be obtained by adding a circuit that passes the comparator 28a that compares with the set temperature threshold value and returns to the gate unit 30c. There is no need.
As a result, according to the present invention, the circuit scale can be reduced and the cost can be reduced compared to a circuit configuration that achieves similar system protection without using the temperature detection device 22 and the protection circuit 28 of the drive circuit 30. Can be planned.

As shown in FIG. 1A, the piezoelectric transformer 16 outputs a secondary AC signal based on the input primary AC signal. In the present embodiment, for example, one of the applicants of the present application. A high power piezoelectric transformer disclosed in Japanese Patent Application Laid-Open No. 2005-129475 can be used. Since the details of the configuration and operation are described in detail in the publication, detailed description thereof will be omitted here, and will be briefly described later.
The piezoelectric transformer 16 of the present embodiment is made of a rectangular plate-shaped piezoelectric ceramic having a predetermined thickness, and an input drive signal is applied to an input electrode pair provided in the thickness direction of the piezoelectric ceramic, and vibrations are generated therefrom. Is taken out from the output electrode pair attached in the length direction as power.

  In the present embodiment, for example, the input voltage of 650 Vp-p of the drive signal input from the drive circuit 30 is boosted by, for example, about 10 times, and an output voltage of 6500 Vp-p is obtained. For example, if the cold cathode tube (CCFL) 18a used for the light emitting unit 18 has a tube length of 527 mm and a tube outer diameter of about 2.6, it can be lit at a voltage of 1000 to 1200 Vrms, but for example, the light emitting unit 18 When two cold cathode tubes 18a are connected in series, the voltage is increased to a voltage of 2000 to 2400 Vrms necessary for lighting the two cold cathode tubes 18a.

  In the present embodiment, a piezoelectric ceramic transformer capable of high power output of 30 W class is used as the step-up piezoelectric transformer 16. However, the present invention is not limited to this, and is used for the light source device 10 and the piezoelectric transformer device 11. Accordingly, for example, an ordinary 3W class low-power output piezoelectric transformer may be used, and conversely, the piezoelectric ceramic 32 (see FIG. 2) is thickened to further increase the power. Also good. In short, a piezoelectric transformer that can output the voltage and power required by the light emitting unit 18 may be used. As described above, the primary AC signal input to the piezoelectric transformer 16 may of course be a single phase with one side grounded (ground; GND).

Incidentally, the piezoelectric transformer 16 includes a temperature detection device 22 for detecting the temperature. The temperature detection device 22 is not particularly limited as long as the temperature of the piezoelectric transformer 16 can be detected, but it is preferable to use a thermistor because of easy handling.
The temperature detection device 22 may be directly attached to the piezoelectric transformer 16 to measure the temperature thereof, or may be attached to a holding mechanism that holds the piezoelectric transformer 16 so as to be able to vibrate, and the piezoelectric transformer 16 via the holding mechanism. You may make it measure the temperature of. Details of the holding mechanism of the piezoelectric transformer 16 and the attachment of the temperature detection device 22 to the piezoelectric transformer 16 or the holding mechanism will be described later.
The detection result of the temperature of the piezoelectric transformer 16 by the temperature detection device 22 is sent to the protection circuit 28 of the drive circuit 30 of the drive unit 14, and when the detected temperature exceeds a predetermined allowable upper limit value, As described above, the control to stop the output of the drive signal from the drive circuit 30 is performed.
The piezoelectric transformer device 11 of the present invention is generally configured as described above.

Next, the two-phase high-voltage signal output from the piezoelectric transformer 16 is input to the light emitting unit 18. The light emitting section 18 of the present embodiment is, for example, a cold cathode tube (CCFL) 18a, preferably a plurality of cold cathode tubes 18a arranged as shown in FIG. For example, preferably, the two cold-cathode tubes 18a are connected in series so that two systems of two-tube serial light sources do not intersect with each other. These two-tube series light sources are arranged in parallel to enable simultaneous lighting.
In this case, the four cold-cathode tubes 18a shown in FIG. 1B are not particularly limited, including their specifications, but as an example, for example, the specifications are a tube length of 527 mm, a tube An outer diameter of 2.6 mm, a tube inner diameter of 2.0 mm, a color temperature of around 6500 K, a Ni electrode, a gas pressure of 70 Torr, and a luminance of about 30000 cd / m ² can be used.

Subsequently, the light emitting unit 18 is connected to the tube current detection circuit 20.
As shown in FIG. 1A, the tube current detection circuit 20 is a tube current of a cold cathode tube 18a disposed in the light emitting unit 18, for example, a tube of a plurality of cold cathode tubes 18a (see FIG. 1B). For example, a toroidal coil in which three coils are wound around a ring-shaped core is used (see FIG. 1B). The two coils are coils of the same polarity and having the same number of windings respectively connected in series to two systems of two-tube series light sources, and the total current of the tube currents flowing through the two systems of two-tube series light sources is calculated. calculate. Another coil is a coil for outputting a total current. The tube current detection circuit 20 is not limited to the circuit configuration described above, and can be realized by a circuit having any other configuration that performs the same function. In addition to the tube current detection circuit 20, a balance circuit that is connected in series and balances the tube currents flowing through the plurality of cold cathode tubes 18 a of the light-emitting unit 18 to equalize, or a plurality of cold cathode tubes 18 a. There may be provided a current difference detection circuit for taking out a current difference which is a difference between the tube currents flowing through the.
As shown in FIG. 1A, the tube current output from the tube current detection circuit 20 is fed back to the voltage controlled oscillation circuit 24 of the oscillation unit 26 described above. The operation of the voltage controlled oscillator 24 when the tube current is supplied is as described above.
The light source device 10 of the present invention is generally configured as described above.

Next, the piezoelectric transformer 16 used in this embodiment will be described in detail.
As shown in FIG. 2, the piezoelectric transformer 16 includes a piezoelectric ceramic 32, first input electrodes 34a and 34b, second input electrodes 36a and 36b, a first output electrode 38, and a second output electrode 40. Then, the input drive signal is applied to the first input electrodes 34a and 34b and the second input electrodes 36a and 36b, which are the provided input electrode pairs, so as to sandwich the piezoelectric ceramic 32 in the thickness direction, and then generated. The power is extracted from the first and second output electrodes 38 and 40, which are output electrode pairs attached in the length direction, using the vibrations generated.

  The piezoelectric ceramic 32 is a rectangular flat plate-shaped piezoelectric ceramic element having a predetermined thickness. For example, the length L is 80 mm, the width W is 18 mm, and the thickness t is 4 mm. can do. In the case of the present embodiment, the piezoelectric ceramic 32 is configured such that the ratio W / L of the dimension L in the length direction to the dimension W in the width direction is around 0.2, and the secondary vibration mode in the length direction ( vibrates in λ mode. Accordingly, the center frequency of vibration is determined by the length dimension L, and the voltage amplification factor is determined by the ratio L / t between the length dimension L and the thickness dimension t.

  As shown in FIG. 2, the piezoelectric ceramic 32 has a first region 32 a, a second region 32 b, a second region from one end (left side in FIG. 2) to the other end (right side in FIG. 2). The area is divided into three areas 32c, a fourth area 32d, and a fifth area 32e, and the ratio of the length of each area in the length direction is about 2: 2: 1: 2: 2. The second region 32b and the fourth region 32d are input units for input voltage (a drive signal input from the drive circuit 30), and the first region 32a and the fifth region 32e are output units for output voltage (high voltage signal), The third region 32c is a rigid part.

The first input electrodes 34a, 34b, the second input electrodes 36a, 36b, the first output electrode 38, and the second output electrode 40 are made of baked silver. The first input electrodes 34a and 34b are respectively disposed on both surfaces (upper and lower surfaces in FIG. 2) of the second region 32b of the piezoelectric ceramic 32 in the thickness direction. Similarly, the second input electrodes 36 a and 36 b are respectively disposed on both surfaces in the thickness direction of the fourth region 32 d of the piezoelectric ceramic 32. Here, the input terminal 42a of the first input electrode 34a and the input terminal 44a of the second input electrode 36a are connected to each other, and the input terminal 42b of the first input electrode 34b and the input terminal 44b of the second input electrode 36b are Are connected to each other.
The first output electrode 38 is disposed on one end face (left face in FIG. 2) in the length direction of the piezoelectric ceramic 32, and similarly, the second output electrode 40 has the other end face (right face in FIG. 2). Is arranged.

  Further, as indicated by an arrow in FIG. 2, the first region 32a is polarized from the second region 32b side toward one end face in the length direction of the piezoelectric ceramic 32, and similarly, the fifth region 32e. Is polarized from the fourth region 32 d side toward the other end face side in the length direction of the piezoelectric ceramic 32. Further, as described above, the second region 32b is from the lower surface side in the thickness direction of the piezoelectric ceramic 32 to the upper surface side, that is, from the first input electrode 34b side of the lower surface toward the first input electrode 34a side of the upper surface. Conversely, the fourth region 32d is directed from the upper surface side in the thickness direction of the piezoelectric ceramic 32 to the lower surface side, that is, from the second input electrode 36a side of the upper surface to the second input electrode 36b side of the lower surface. Are polarized. That is, in the piezoelectric ceramic 32, the second region 32b and the fourth region 32d are polarized in opposite directions. The third region 32c is in an unpolarized state.

As described above, two sets of input electrodes, that is, the first input electrodes 34a and 34b and the second input electrodes 36a and 36b are attached in the thickness direction of the second region 32b and the fourth region 32d of the piezoelectric ceramic 32, respectively. However, in the second region 32b and the fourth region 32d, the directions of polarization with respect to the thickness direction are different by about 180 degrees. For example, in the second region 32b, it is plus on the first input electrode 34a side on the upper surface, and is minus on the first input electrode 34b side on the lower surface, and in the fourth region 32d, it is minus on the second input electrode 36a side on the upper surface. The second input electrode 36a side is configured to be positively polarized.
The piezoelectric transformer 16 is input from the drive circuit 14 (see FIG. 1) in the thickness direction thereof, that is, to the first input electrode 34a and the second input electrode 36a, and the first input electrode 34b and the second input electrode 36b. As the voltage, a two-phase drive signal (sine wave AC signal) having a phase difference of 180 degrees is input, or a single-phase drive signal is input to one of them and the other is grounded.

Specifically, when two-phase drive signals having opposite phases are input, the first input electrode 34a and the second input electrode 36a in which the input terminals 42a and 44a on the upper surface side in FIG. 2 are connected to each other. In FIG. 2, one drive signal is input, and the other drive signal is input to the first input electrode 34b and the second input electrode 36b in which the input terminals 42b and 44b on the lower surface side in FIG. 2 are connected to each other. .
On the other hand, when a single-phase drive signal is input, a single-phase drive signal is applied to the first input electrode 34a and the second input electrode 36a to which the input terminals 42a and 44a on the upper surface side in FIG. Is input, and the first input electrode 34b and the second input electrode 36b to which the input terminals 42b and 44b on the lower surface side in FIG. 2 are connected to each other are grounded.

When a two-phase or single-phase drive signal is applied as an input voltage, stress is generated in the piezoelectric ceramic 32 due to the inverse piezoelectric effect, and the second region 32b and the fourth region 32d are mechanically moved in the thickness direction. Causes distortion. Then, a potential difference occurs in the polarization direction in the first region 32a and the fifth region 32e due to the piezoelectric effect. As a result, from the first output electrode 38 and the second output electrode 40, a two-phase high-voltage signal (sine wave AC signal) having a frequency substantially equal to that of the drive signal and having a 180-degree phase different from that of the drive signal is different. , Through each output terminal 46 and 48 simultaneously.
Since the unpolarized third region 32c is provided in the central portion of the piezoelectric ceramic 32, the unpolarized portion functions as a strong rigid body portion that does not vibrate, and is generated when high power (high power) is output. The vibration mode in the torsional direction and the vibration mode in the meandering direction can be more suitably suppressed.

Next, a holding mechanism that holds the piezoelectric transformer 16 so as to vibrate and a mounting structure of the temperature detection device 22 will be described in detail.
FIG. 3 is a schematic perspective view showing a schematic structure of an embodiment of a piezoelectric ceramic transformer unit (hereinafter simply referred to as a piezoelectric transformer unit) including the piezoelectric ceramic transformer, its holding mechanism, and a temperature detection device shown in FIG. . 4 (a) and 4 (b) are a schematic partially broken plan view and a partially broken side view of the piezoelectric transformer unit shown in FIG. 3, respectively. FIGS. 4 (c) and 4 (d) FIG. 5 is a view along line CC and line DD in FIG. 5A and 5B are a schematic side view and a schematic cross-sectional view, respectively, of the holding member shown in FIG.

As shown in FIGS. 3, 4 (a), (b), (c), and (d), the piezoelectric transformer unit 50 includes the first input electrodes 34 a and 34 b and the second input electrodes 36 a and 36 b on the piezoelectric ceramic 32. The piezoelectric transformer 16 in which the first output electrode 38 and the second output electrode 40 are formed, and a holding member 52 (52a, 52b) that is attached to the outer periphery of the piezoelectric transformer 16 and holds the piezoelectric transformer 16 so as to vibrate. A substrate 54 such as a printed circuit board that functions as a base for mounting the piezoelectric transformer 16, a fixing member 56 (56a, 56b) for fixing the piezoelectric transformer 16 to the substrate 54 via holding members 52a and 52b, and temperature detection A thermistor 58a that is embedded and held in the holding member 52a as the device 22 and attached so as to contact the surface of the piezoelectric transformer 16; And a thermistor 58b attached to the surface of the fixing member 56b.
Conductors (lead wires) 59a and 59b are connected to the thermistors 58a and 58b, respectively, and these conductors 59a and 59b constitute the drive unit 14 that constitutes the piezoelectric transformer device 11 of the light source device 10 shown in FIG. Specifically, one of the conductors 59a and 59b is connected to the input side of the comparator 28a of the protection circuit 28, and the other is grounded.

  As shown in FIG. 5A, the holding member 52 is formed using an elastic material such as a rubber material, and has a rectangular opening 53 a into which the piezoelectric transformer 16 is inserted. The shape of the opening 53 a of the holding member 52 is substantially the same as the outer shape when the piezoelectric transformer 16 is cut in the width direction (direction perpendicular to the length direction), and is slightly smaller than the outer shape of the piezoelectric transformer 16. It is preferable that By slightly reducing the outer shape of the piezoelectric transformer 16, the piezoelectric transformer 16 can be clamped with a predetermined pressure when the holding member 52 is fitted to the outer periphery of the piezoelectric transformer 16, and the piezoelectric transformer 16 is held. Deviation from the member 52 is suppressed. Further, the holding member 52 may be bonded to the piezoelectric transformer 16 with an adhesive in order to further suppress the displacement of the piezoelectric transformer 16.

  Further, as shown in FIG. 5B, the holding member 52 is formed such that the surface (inner wall surface) 53b in contact with the piezoelectric transformer 16 is wider than the outer surface (outer peripheral surface) 53c. The cross-sectional shape is such that the width gradually decreases from the inside toward the outside. That is, the cross-sectional shape of the holding member 52 is substantially trapezoidal as shown in FIG. 5B, and the thickness of the holding member 52 increases as the distance from the center increases in the side surface, that is, in the width direction of the holding member 52. The taper shape is gradually thinned, that is, a mountain skirt shape (taper shape). As described above, the holding member 52 has a thick portion 53d having a constant thickness corresponding to the outer peripheral surface 53c, and a thin portion (tapered portion) that is located on both sides of the thick portion 53d and has a mountain skirt shape like a mountain skirt. ) 53e.

As shown in FIGS. 3 and 4, the holding member 52 (52a, 52b) is provided at a position that becomes a node of vibration when the piezoelectric transformer 16 is driven to vibrate. Since the piezoelectric transformer 16 shown in FIG. 3 is configured to vibrate in the secondary mode, the distance from one end of the piezoelectric transformer 16 is 1/4 of the length of the piezoelectric transformer 16 (second region 32b). And holding member 52a, 52b is attached to the part used as 3/4 (4th field 32d).
Further, since the position of the node of the piezoelectric transformer 16 varies depending on the vibration mode, for example, when the piezoelectric transformer 16 is used by vibrating in the primary mode, one holding member is provided at the substantially central portion of the piezoelectric transformer 16. 52 may be provided. In this case, a holding member or a support member may be provided on the abdomen part supplementarily using an elastic body that is not stable and therefore is difficult to inhibit vibration. When the piezoelectric transformer 16 is vibrated in the tertiary mode and used, the distance from one end of the piezoelectric transformer 16 is 1/6, 3/6, and 5/6 of the length of the piezoelectric transformer 16, respectively. What is necessary is just to provide the holding member 52 in at least one place of the part used as. When the piezoelectric transformer 16 is vibrated in the secondary mode and used, the holding member 52 may be provided at the antinode position of the central portion of the piezoelectric transformer 16 to fix the piezoelectric transformer 16.

As shown in FIGS. 3 and 4, the piezoelectric transformer 16 is a substrate by a fixing member 56 (56a, 56b) in a state of a piezoelectric transformer assembly in which the portions of the nodes are respectively held by holding members 52 (52a, 52b). 54 is fixed. As shown in FIGS. 3, 4 (c), and (d), the fixing member 56 (56 a, 56 b) has a narrow width of the holding member 52 (52 a, 52 b) that holds the piezoelectric transformer 16 when fixed. The flat end portion 57a in contact with the outer peripheral surface 53c, that is, the narrow inner surface 53b on the opposite side of the wide inner wall surface 53b in contact with the piezoelectric transformer 16, and both ends of the flat portion 57a are substantially perpendicular to the flat end portion 57a in the same direction. It has a pair of leg portions 57b bent in the direction toward the substrate 54, and a pair of fixed end portions 57c that are located at the lower end portions of the leg portions 57b and connected to the substrate 54, respectively.
Accordingly, the inner wall surface of the flat end portion 57a and the pair of leg portions 57b of the fixing member 56 is pressed against the outer peripheral surface 53c of the holding member 52, and the holding member 52 is pressed by the fixing member 56, and the fixing member The piezoelectric transformer 16 (piezoelectric transformer assembly) is attached to the substrate 54 by soldering the portions of the pair of fixed end portions 57 c that serve as the legs of both end portions 56 to the substrate 54. Here, the fixing member 56 may be fixed by being adhered to the holding member 52 with an adhesive or the like.

  As shown in FIGS. 3, 4A, 4B, and 4C, the thermistor 58a reliably and firmly contacts the surface of the piezoelectric transformer 16, specifically, the upper surface of the second input electrode 36a. A concave portion is provided on the inner wall surface 53b of the holding member 52a so that the piezoelectric transformer 16 is not displaced or detached even if it vibrates, and is attached so as to be embedded in the concave portion. Since the thermistor 58a attached in this way requires processing for providing a recess in the inner wall surface 53b of the holding member 52a, it takes time to install, but since it is directly fixed on the piezoelectric transformer 16, it has a thermal response. The temperature of the piezoelectric transformer 16 can be measured without delay. The method of fixing the thermistor 58a to the surface of the piezoelectric transformer 16 is not particularly limited to this, and the thermistor 58a may be fixed using an adhesive, a pressure-sensitive adhesive, an adhesive sheet, a pressure-sensitive adhesive sheet, or the like.

  On the other hand, as shown in FIGS. 3, 4A, 4B, and 4D, the thermistor 58b is formed on the flat end portion 57a of the fixing member 56b that fixes the holding member 52b of the piezoelectric transformer 16 on the substrate 54. It is securely and securely attached to the surface. At this time, in order to measure the temperature of the piezoelectric transformer 16 by the thermistor 58b more accurately and with quick response, it is preferable to use a material having high thermal conductivity as the holding member 52b and the fixing member 56b. The thermistor 58b attached in this way has temperature measurement accuracy and responsiveness depending on the thermal conductivity of the holding member 52b and the fixing member 56b, but may be fixed on the flat end 57a of the fixing member 56b. Is easy. The method of fixing the thermistor 58b to the surface of the fixing member 56b is not particularly limited to this, and it may be fixed using an adhesive, an adhesive sheet, an adhesive sheet or the like in addition to the adhesive.

As in the illustrated example, the two thermistors 58a and 58b are preferably attached at positions where the holding members 52a and 52b of the piezoelectric transformer 16 are attached, respectively. The reason is that the position where the holding members 52a and 52b are attached, which becomes the vibration node when the piezoelectric transformer 16 vibrates, generates the largest amount of heat, and the temperature is higher than the other positions.
That is, when a large electric power is input to the piezoelectric transformer 16 and an overload occurs, the surface temperature of the vibration node of the piezoelectric transformer 16 rapidly increases, and usually Δt <20 to At about 30 degrees, the breakage mode of the nonlinear region starts when the temperature rise exceeds 80 degrees. By the way, the highest temperature rise on the piezoelectric transformer 16 is the vibration node. Therefore, the best way to detect the failure mode is to look at the node temperature. Therefore, a temperature detection device 22 such as the thermistor 58 (58a and 58b) is provided on the surface portion of the vibration node of the piezoelectric transformer 16 as shown in the figure, and the system (drive) is detected immediately before reaching the breakdown mode. This is because the drive circuit 30) of the unit 14 may be shut down. Further, as described above, the vibration node portion of the piezoelectric transformer 16 is also a part for fixing the piezoelectric transformer 16 to the substrate 54, and a temperature detection means such as a thermistor 58 may be attached as shown in the illustrated example. This is because the vibration of the piezoelectric transformer 16 is not affected.

In the illustrated example, the two thermistors 58 (58a and 58b) are mounted at different locations. However, these two thermistors 58 are attached to the surface of the piezoelectric transformer 16 at the same location, for example, the thermistor 58a. It may be fixed directly, or may be fixed to the upper surface of the fixing member 56b like the thermistor 58b, or not only two thermistors may be attached but only one of them may be attached. Furthermore, the place where the thermistor is attached is not limited to the illustrated example, and is not particularly limited. If the surface temperature of the piezoelectric transformer 16 or the surface temperature of the piezoelectric ceramic 32 can be measured directly or indirectly, or these surface temperatures. Any place may be used as long as the temperature can be measured. Furthermore, the temperature detection device 22 is not limited to the thermistor 58, and if the surface temperature of the piezoelectric transformer 16 or the surface temperature of the piezoelectric ceramic 32 can be measured directly or indirectly, or a temperature equivalent to these surface temperatures is used. Any temperature detection device may be used as long as measurement is possible, and any temperature detection means and any method may be used.
As described above, in the present invention, by providing temperature detecting means such as a thermistor on the surface of the piezoelectric transformer 16 or at another location having the same temperature as this surface, the driving safety of the piezoelectric transformer 16 is enhanced. Therefore, various protection circuits which are an obstacle to cost reduction due to an increase in circuit scale can be reduced, so that the circuit scale can be reduced and the cost of the apparatus can be reduced.

The material of the holding member 52 (52a, 52b) used in the present invention may be any material as long as the piezoelectric transformer 16 can be held so as to vibrate. For example, an elastic material such as a fixing rubber material, for example, a hardness of 20 Silicon rubber or the like of a certain degree can be used, which is preferable because it can be electrically insulated and vibration loss at the holding portion is small.
The material of the fixing member 56 (56a, 56b) used in the present invention may be any material as long as the holding member 52 for holding the piezoelectric transformer 16 can be fixed to the substrate 54. For example, the thickness is about 100 microns. It is best to use a soft copper foil plate with a band shape. Furthermore, it is possible to use one with an adhesive applied to the silicon rubber side, which is easy to assemble and has little loss. It is suitable as a fixing member for the reason. Such a fixing member made of a strip-shaped copper foil plate can be easily fixed to a board such as a printed board easily.
In addition, the fixing member 56 may be fixed by being adhered to the holding member 52 with an adhesive or the like. Further, as the fixing member 56, for example, a plate-like member such as metal or plastic can be processed into a predetermined shape and used.

  In addition, the material of the substrate 54 used in the present invention may be any material as long as the piezoelectric transformer 16 can be attached, and specifically, the holding member 52 that holds the piezoelectric transformer 16 can be fixed. A substrate or the like can be used. For example, a material such as paper, glass cloth, glass nonwoven fabric, or the like that is hardened with a resin such as a phenol resin, an epoxy resin, or a polyimide resin, and a thickness (t = ) A double-sided board with a solder leveler of about 1.6 mm, a single-sided board, etc. can be used, and both sides are 1.6 mm thick, including the glass substrate, because it is more rigid and the wiring pattern can be minimized. A substrate is preferred.

In the present embodiment, the holding member 52 having the shape shown in FIG. 5 is used, but the present invention is not limited to this. For example, a holding member of a type that holds around the outer periphery of the piezoelectric transformer 16 like the holding member 52 having the shape shown in FIG. 5 can use holding members having other shapes.
FIG. 6 shows another embodiment of a piezoelectric transformer unit using a holding member of another shape of a type that holds around the outer periphery of the piezoelectric transformer 16.
A piezoelectric transformer unit 51a shown in FIG. 6 uses a holding member 60 and a fixing member 62 instead of the piezoelectric transformer unit 50 shown in FIGS. 4C and 4D, and the holding member 52 and the fixing member 56. Since it has the same configuration except for the points, detailed description thereof will be omitted, and differences will be mainly described.
In the holding member 60 shown in FIG. 6, two protrusions (bosses) 60 b are formed on the outer peripheral surface 60 a that contacts the fixing member 62. When the holding member 60 having such a shape is used, the fixing member 62 is formed with a through hole 62 a that fits with the protruding portion 60 b of the holding member 60. Then, the protrusion 60 b of the holding member 60 is fitted into the through hole 62 a of the fixing member 62, and the piezoelectric transformer 16 is fixed to the substrate 54 by the fixing member 62. Thereby, the shift | offset | difference to the length direction of the piezoelectric transformer 16 can be suppressed further, and a piezoelectric transformer can be fixed stably at the time of a drive.

Also in this case, similarly to the holding member 52a shown in FIG. 4C, the thermistor 58a may be directly fixed to the surface of the piezoelectric transformer 16 so as to be embedded and held in the inner peripheral wall surface 62b of the holding member 60. Alternatively, the thermistor 58b indicated by the broken line may be fixed to the upper surface of the fixing member 62 as in the example shown in FIG. These can be used in place of the examples shown in FIGS. 4 (c) and 4 (d), respectively. Alternatively, the thermistor 58b may be fixed to the upper surface of the protrusion 60b of the holding member 60.
Here, two protrusions are formed on the holding member, but the number of protrusions may be one, or may be three or more.

  Furthermore, as shown in FIG. 7, a holding member 64 in which a groove 64b is formed on the outer peripheral surface 64a on the side in contact with a fixing member (not shown) may be used. The holding member 64 shown in FIG. 7 is an outer surface (outer peripheral surface) 53c of the holding member 52 shown in FIG. 5A, that is, the center of the upper surface 53c of the holding member 52 shown in FIG. It can be said that a groove extending along the outer periphery of the holding member 52 is provided. When the holding member 64 having such a shape is used, a fixing member (not shown) having a width substantially the same as the width of the groove 64b is used, and a fixing member (not shown) having the substantially same width is used for the groove 64b of the holding member 64. The piezoelectric transformer unit 50 may be fixed to the substrate 54.

Further, in the present invention, the holding member is formed using an elastic material having conductivity, the fixing member 56 is formed using a material exhibiting electrical conduction such as a copper plate, and the substrate 54 is formed on the base described above. A material such as a double-sided substrate or a single-sided substrate made of a material obtained by hardening a material with a resin can also be used.
Conventionally, even a piezoelectric transformer that is mechanically fixed and mounted on an electric board is used as a wiring material such as a wire or a flexible board (FFC, FPC) in order to connect to the electric board. There was no choice but to use flexible materials, and it was necessary to connect them with solder or the like. For this reason, it takes a lot of man-hours for attachment, which hinders cost reduction. In addition, if the wiring member attached to the piezoelectric transformer vibrates in response to the vibration of the piezoelectric transformer, and the vibration of the wiring member is included in the audible band, a phenomenon called so-called noise occurs, and noise that is heard by the ear There was a case.

Therefore, in the present invention, in order to prevent such squeaking of the wiring vibration, the holding member for holding the piezoelectric transformer with respect to the fixing member is made of an elastic material having conductivity, and the holding member is It can also be used as a substitute for the wiring member.
8 to 10 show an embodiment of a piezoelectric transformer unit in which the holding member is made of an elastic material having conductivity.
FIG. 8 is a schematic partially exploded cross-sectional view of another embodiment of the piezoelectric transformer unit used in the present invention. 9A is a schematic side view of the piezoelectric transformer unit shown in FIG. 8, and FIGS. 9B and 9C show the BB line and the CC line in FIG. 9A, respectively. It is an arrow view. FIG. 10 is a schematic perspective view of the holding member shown in FIG.
The piezoelectric transformer unit 51b shown in FIGS. 8 and 9 (a), 9 (b) and 9 (c) and the piezoelectric transformer unit 50 shown in FIGS. 4 (a), 4 (b), 4 (c) and 4 (d) are held. Since it has the same configuration except that a holding member 66 composed of two holding bodies 67 is used instead of the member 52, the detailed description thereof will be omitted and mainly the differences will be described. Will be described.

In the piezoelectric transformer unit 51b shown in FIGS. 8 and 9A to 9C, the piezoelectric transformer 16 is held between the fixed member 56 and the substrate 54 via the holding member 66, and the thermistor 58 is a piezoelectric transformer. It is attached to a position for measuring 16 temperatures. Here, the holding member 66 is composed of two holding bodies 67 using an elastic material having conductivity, and the piezoelectric transformer 16 is interposed via the two holding bodies 67 of the holding members 66 (66a, 66b). The fixing member 56 (56a, 56b) is fixed to the substrate 54.
In this piezoelectric transformer unit 51b as well, the thermistor 58a is used as the temperature detection device 22 in the same manner as the piezoelectric transformer unit 50 shown in FIGS. 3 and 4A to 4B and the piezoelectric transformer unit 51a shown in FIG. Is embedded and held in a holding body 67 on the upper side of the holding member 66a in the drawing, is attached so as to contact the surface of the piezoelectric ceramic transformer 16, and the thermistor 58b is fixed to the two holding bodies 67 of the holding member 66b. The fixing member 56b can be attached to the surface of the flat portion 57a.

The holding member 66 (66 a, 66 b) shown in these drawings is composed of two holding bodies 67. As shown in FIG. 10, each holding body 67 has an elongated rod-like shape, and has a substantially trapezoidal cross-sectional shape like the holding member 52 shown in FIG. 5B described above. In the example shown in FIGS. 4A to 4D, the piezoelectric transformer 16 is held by rotating the piezoelectric transformer 16 with the holding member 52, but here, the two are arranged so as to face each other via the piezoelectric transformer 16. Two holding bodies 67 are arranged to hold the piezoelectric transformer 16.
At this time, the wide surface 67 a of the holding body 67 is in contact with the first input electrodes 34 a and 34 b and the second input electrodes 36 a and 36 b of the piezoelectric transformer 16, and the narrower surface 37 b of the holding body 67 is the fixing member 56. It arrange | positions so that an inner surface may be contact | connected. When the holding member 66 is configured using a material having conductivity, the holding member 66 is not a holding member having a structure that circulates the piezoelectric transformer 16, and two holding members having a shape extending in the width direction of the piezoelectric transformer 16 are used. Using the body 67, one surface of the piezoelectric transformer 16 and the opposite surface thereof are independently held.
In the example shown in FIGS. 8 and 9A to 9C, the fixing member 56 is longer in both length and width than the fixing member shown in FIGS. 3 and 4, but the flat portion 57a and the pair of leg portions 57b. And the piezoelectric transformer 16 is being fixed to the board | substrate 54 using the fixing member of the same structure provided with a pair of fixed edge part 57c.

  In addition, as shown in FIG. 8, eight substantially rectangular lands are formed on the substrate 54. The lands 68 a and 68 d are provided along a direction perpendicular to the length direction of the piezoelectric transformer 16. The lengths of the lands 68a and 68d are slightly longer than the width of the piezoelectric transformer 16 (the length in the direction perpendicular to the longitudinal direction). The lands 68a and 68d are disposed at positions corresponding to the holding member 66 of the piezoelectric transformer 16. Thus, when the piezoelectric transformer 16 is mounted on the substrate 54, the holding body 67 disposed in contact with the first input electrode 34b and the second input electrode 36b on the lower surface side of the piezoelectric transformer 16 is landed with the lands 68a and 68d. Will be in contact. Since the holding body 67 has conductivity as described above, the first input electrode 34b and the second input electrode 36b of the piezoelectric transformer 16 are energized with the land 68a and the land 68d through the holding body 67, respectively. Become.

Further, lands 68b and lands 68c are formed on both sides of the land 68a in the length direction so as to be separated from the lands 68a by a predetermined distance. Similarly, on both sides of the land 68d in the length direction, lands 68e and lands 68f are formed at predetermined intervals from the lands 68d. When the piezoelectric transformer 16 is fixed to the substrate 54 using the fixing member 56, both end portions 57c of each fixing member 56 are soldered to the lands 68b and 68c and the lands 68e and 68f.
Further, lands 68g and 68h connected to the first output electrode 38 and the second output electrode 40 of the piezoelectric transformer 16 are formed on the substrate 54, respectively. The lands 68g and 68h are provided so as to be positioned in the vicinity of the first output electrode 38 and the second output electrode 40 of the piezoelectric transformer 16 when the piezoelectric transformer 16 is fixed to the substrate 54. Conductive wires connected to the output electrodes 38 and 20 of the piezoelectric transformer 16 are connected to the lands 68g and 68h.

  As described above, the holding member is configured using an elastic material having conductivity, and by using this holding member as a substitute for the wiring member, the wiring member does not have to be soldered to the input electrode of the piezoelectric transformer. The wiring member can be electrically connected to the input electrode. As a result, the number of steps such as soldering becomes unnecessary, and the number of steps can be reduced as compared with the conventional case. In the piezoelectric transformer of this embodiment, since the holding member and the first and second input electrodes are provided at the vibration node of the piezoelectric transformer, both the holding of the piezoelectric transformer and the wiring to the input electrode are used. Furthermore, it is possible to prevent the wiring member of the input part from vibrating in response to the vibration of the piezoelectric transformer, to prevent the noise due to the wiring of the input electrode, and only the noise due to the wiring connected to the output electrode. Therefore, the overall squeal is reduced. Further, in order to eliminate the wiring of the output unit, a structure described later may be used. As described above, the present invention has an advantage that, other than the above change, there is no change in the processing method and the change in the peripheral circuit.

In the present invention, as shown in FIGS. 5 to 7, holding members 52, 60 and 64 of the type that circulates and holds the outer periphery of the piezoelectric transformer 16, and sandwiching the piezoelectric transformer 16 as shown in FIG. 8. Since the holding member 66 of the type that holds the piezoelectric transformer 16 by making the two holding bodies 67 face each other is used, as shown in FIGS. 3 and 8, the piezoelectric transformer 16 and the fixing member 56 or 62 A holding member 52, 60, 64 or holding member 66 (holding body 67) formed of an elastic material is interposed between the holding member 52, 60, 64, or 66, and the piezoelectric transformer 16 is held by the holding member 52, 60, 64, or 66. The piezoelectric transformer 16 can be fixed on the substrate 54 without inhibiting the vibration of the transformer 16. Further, as shown in FIGS. 5 to 7 and FIG. 10, the shape of the holding members 52, 60 and 64 and the shape of the holding body 67 constituting the holding member 66 are as follows. As a result, even if the piezoelectric transformer 16 is displaced in the longitudinal direction due to vibration, the holding member 52, 60, 64 or the thin base portion of the holding body 67 is moved along with the movement of the piezoelectric transformer 16, so that the holding member 52, 60, 64 or the holding body 67 and the surface of the piezoelectric ceramic 32 of the piezoelectric transformer 16 are bent and bent, and the skirt portion between the holding members 52, 60, 64 or the holding body 67 and the piezoelectric transformer 16 is bent. Intervene.
For this reason, the thickness of the holding members 52, 60, 64 or the holding body 67 fixed by the fixing member 56 or 62 is increased by the amount of the retracted skirt, and the movement of the piezoelectric transformer 16 in the length direction is increased. Will be limited.

That is, the fixing member 56 or 62 is fixed to the substrate 54, and the distance between the substrate 54 and the fixing member 56 or 62 is constant, so that the holding member 52, 60, 64 or the holding member 66 is moved by the movement of the piezoelectric transformer 16. When the skirt portion of the holding body 67 is bent and the thickness is increased, the movement of the piezoelectric transformer 16 in the length direction is restricted. Thus, even if the piezoelectric transformer 16 vibrates, the piezoelectric transformer 16 is stably held on the substrate.
In addition, since the holding members 52, 60, 64 and the holding body 67 of the holding member 66 have a larger surface in contact with the surface of the piezoelectric ceramic 32 of the piezoelectric transformer 16, the pressure applied from the fixing member 56 is reduced on the piezoelectric ceramic 32. In addition to the effect of reducing the vibration inhibition of the piezoelectric ceramic 32, the contact area between the surface of the piezoelectric ceramic 32 and the holding members 52, 60, 64 and the holding body 67 is increased. is there. The holding member 52, 60, 64 and the holding member 67 between the holding member 66 and the fixing member 56 or 62 can be mechanically fixed by processing a boss or the like, but the holding member 5252, 60, 64 or the holding member The surface of the holding body 67 of 66 and the surface of the piezoelectric ceramic 32 of the piezoelectric transformer 16 is very effective because such processing cannot be performed. There is a method of stopping these with an adhesive, but even in this case, the holding member 52, 60, 64 or the holding body 67 of the holding member 66 can increase the bonding area and is effective.

  In the embodiment shown in FIGS. 3 to 9, the holding member 52, 60, 64 or 66 is provided so as to extend in a direction perpendicular to the longitudinal direction of the piezoelectric transformer 16. The position where the holding member is provided can be changed according to the vibration mode. For example, when a piezoelectric transformer having the same shape as the piezoelectric transformer 16 shown in FIG. 2 is used in a mode that vibrates in the width direction of the piezoelectric transformer, a holding member is provided so as to extend in the longitudinal direction of the piezoelectric transformer. May be. In this case, it may be provided so as to circulate in the longitudinal direction of the piezoelectric transformer, or as shown in FIG. 10, when a holding member is configured using two holding bodies, the piezoelectric transformer is interposed between the holding bodies. May be interposed. Furthermore, when the piezoelectric transformer is used in a mode that vibrates in the thickness direction, a holding member may be provided on the side surface of the piezoelectric transformer. In this case, a holding member may be provided so as to go around the side surface of the piezoelectric transformer, or a rod-like holding body as shown in FIG. 10 may be provided on each side surface of the piezoelectric transformer.

In the above embodiment, the piezoelectric transformer assembly is fixed to the substrate using two fixing members. However, in the present invention, the piezoelectric transformer assembly may be fixed to the substrate using one fixing member. In this case, for example, in FIG. 3 or 4, the length of the fixing member is longer than the arrangement interval of the two holding members 52 a and 52 b that hold the piezoelectric transformer 16 in the length direction of the piezoelectric transformer 16. The fixing member may be configured as described above. As a result, the outer surfaces 53c of the two holding members 52a and 52b of the piezoelectric transformer 16 arranged at a predetermined interval can be pressed simultaneously. In FIG. 3, a flat plate member longer than the interval between the two holding members 52a and 52b of the piezoelectric transformer 16 is disposed on the upper surface of the two holding members 52a and 52b, and the plate member is attached by a fastener or the like. You may fix to a board | substrate. In this case, the plate member and the fastener function as a fixing member.
Thus, in the present invention, the shape and dimensions of the fixing member are not particularly limited as long as the piezoelectric transformer assembly including the piezoelectric transformer and the holding member can be fixed to a base such as a printed circuit board. .

In the above-described embodiment, the case where the piezoelectric transformer 16 held by the holding members 52, 60, 64 or 66 is fixed to the substrate 54 using the fixing members 56 and 62 has been described. A piezoelectric transformer assembly including a piezoelectric transformer may be accommodated in the case. In this case, the case containing the piezoelectric transformer assembly is fixed to the substrate.
Hereinafter, an embodiment in which a piezoelectric transformer is fixed to a substrate in a state of being accommodated in a case via a holding member will be described with reference to FIGS. 11 to 13.

FIG. 11 is a perspective view schematically showing an appearance of an embodiment of a case for accommodating a piezoelectric transformer assembly that holds a piezoelectric transformer with a holding member. 12 and 13 are a perspective view of the upper case shown in FIG. 11 as viewed from below and a perspective view of the lower case as viewed from above.
A case 70 shown in FIG. 11 is a piezoelectric transformer 16 that is held by the holding member 52 having the structure shown in FIGS. It is a case for accommodating a transformer assembly. Both cases 70 are made of an electrically insulating material, for example, a plastic upper case 72 and a lower case 74.
In the present invention, when the piezoelectric transformer assembly is housed in a case and used, the upper case functions as a fixing member, the lower case functions as a base, and the piezoelectric transformer assembly is housed in the case by a holding member. A piezoelectric transformer unit is configured. Therefore, the “fixing member” in the present invention is a concept including not only the sheet metal such as the above-described fixing members 56 and 62 but also the upper case, and the term “base” refers to a wiring board such as the above-described board 54 or a printed board. This is a concept including not only a substrate such as a lower case.

  As shown in FIGS. 12 and 13, rectangular recesses 72a and 74a are formed in the upper case 72 and the lower case 74, respectively, and the holding member 52 shown in FIG. 3 is formed in these recesses 72a and 74a. The piezoelectric transformer 16 (piezoelectric transformer assembly) held in is stored. 12 and 13, the illustration of the piezoelectric transformer 16 is omitted. When the holding member 52 (52b) and the upper case 72 are made of a member having good heat conductivity, the concave portion of the upper case 72 that comes into contact with the holding member 52b holding the accommodated piezoelectric transformer 16 is used. The thermistor 58b may be attached to the portion 72a (see FIG. 12) or the portion on the upper surface side of the upper case 72 (see FIG. 11) opposite thereto by bonding or the like. In this case, the thermistor 58b can be easily attached. Here, when the thermal conductivity of the upper case 72 of the holding member 52 (52b) is low, as described above, the thermistor 58b is attached between the surface of the piezoelectric transformer 16 and the holding member 52b, similarly to the thermistor 58a. Is preferred. In this case, the holding member 52 that circulates the piezoelectric transformer 16 has a recess for attaching the thermistor, and if the holding member 52 is an elastic body, the thermistor 58 attached when the piezoelectric transformer assembly is manufactured is attached to the case 70. Since the piezoelectric transformer assembly does not fall off when stored, it is very easy to incorporate the piezoelectric transformer assembly. Of course, including this case, if the thermistor 58a is attached to the piezoelectric transformer 16 (piezoelectric transformer assembly), the thermistor 58b need not be attached to the upper case 72. Further, since the space is closed by the case 70, as a method for indirectly measuring the temperature of the piezoelectric transformer 16, the thermistor 58 is bonded to the inside of the case 70 close to the holding member 52 so as not to contact the holding member 52. You may make it fix with an agent.

  The lower case 74 is provided with four screw holes 76 for fixing the case 70 to the substrate with screws. Further, the lower case 74 includes first input electrodes 34a and 34b, second input electrodes 36a and 36b, a first output electrode 38, and a second output electrode 40 of the piezoelectric transformer 16 shown in FIGS. Four grooves 74b, 74c, 74d and 74d are formed for taking out the connected lead wire and the lead wire 59a of the thermistor 58a or the lead wire 59b of the thermistor 58b. The grooves 74b and 74e formed at one end and the other end in the longitudinal direction of the case 74 are grooves for taking out the lead wires of the output electrodes of the piezoelectric transformer, and the direction perpendicular to the length direction of the case 74 Grooves 74c and 74d formed at one end of each of the first and second input electrodes 34a and 34b and the thermistor 58b, and the second input electrodes 36a and 36b and the thermistor 58a, respectively. .

The piezoelectric transformer 16 is housed in a case 70 having such a structure as a piezoelectric transformer assembly held by a holding member. At this time, the holding member 52 (52a, 52b) of the piezoelectric transformer 16 comes into contact with the inner wall surface of the case 70 and is pressed by the wall surface, whereby the piezoelectric transformer 16 is fixed and held inside the case 70. The piezoelectric transformer assembly housed in the case 70 may include the thermistor 58a and further the thermistor 58b in addition to the piezoelectric transformer 16 and the holding members 52a and 52b.
Here, the four grooves 74b, 74c, 74d and 74e for taking out the conducting wire are formed in the lower case 74. However, these grooves may be formed in the upper case 72, or both the upper case and the lower case. You may form a groove | channel in this. Further, the piezoelectric transformer 16 may be housed in the case 70 while being fixed to the substrate 54 as in the piezoelectric transformer unit 50 shown in FIG. In this case, it is more reliable if the substrate 54 is fixed to the inner recess 74a of the lower case 74 with an adhesive or the like.

Next, another embodiment of the case for accommodating the piezoelectric transformer will be described.
FIG. 14 is a perspective view schematically showing the external appearance of the entire case of another embodiment of the case accommodating the piezoelectric transformer assembly. 15 and 16 are a perspective view of the upper case shown in FIG. 14 as seen from below and a perspective view of the lower case as seen from above.
A case 80 shown in FIG. 14 is composed of an electrically insulating material, for example, a plastic upper case 82 and a lower case 84. As shown in FIGS. 14 and 15, the upper case 82 is electrically connected to the first and second input electrodes 34a and 36a of the piezoelectric transformer 16 shown in FIG. Terminals 86 and 88 are provided. As shown in FIG. 15, these terminals 86 and 88 extend in a direction parallel to the surface of the upper case 82 and perpendicular to the longitudinal direction of the upper case 82. It is provided so as to penetrate the side surface and be exposed inside the upper case 82. The exposed portions 86a and 88a inside the upper case 82 of the terminals 86 and 88 are positioned so as to come into contact with a holding member 97 (see FIG. 17) of the piezoelectric transformer 16 described later when the piezoelectric transformer 16 is disposed in the upper case 82. Be placed.

Similarly, the lower case 84 is provided with terminals 90 and 92 that are electrically connected to the first and second input electrodes 34b and 36b of the piezoelectric transformer 16 shown in FIG. As shown in FIG. 16, the terminals 90 and 92 are parallel to the surface of the lower case 84 and extend in a direction perpendicular to the longitudinal direction of the lower case 84, and penetrate both sides of the lower case 84. In addition, it is provided so as to be exposed inside the lower case 84. Further, the exposed portions 86a and 88a inside the lower case 84 of the terminals 90 and 92 come into contact with a holding member 97 (see FIG. 17) of the piezoelectric transformer 16 described later when the piezoelectric transformer 16 is disposed on the lower case 84. Placed in position. Further, the lower case 84 is provided with conductors connected to output electrodes 38 and 40 of the piezoelectric transformer 16 of the piezoelectric transformer assembly described later, and grooves 84a and 84b for taking out the conductors 59a and 59b of the thermistors 58a and 58b, respectively. It has been.
Further, as shown in FIG. 14, when the upper case 82 and the lower case 84 are combined and the piezoelectric transformer 16 is accommodated, the terminals of the upper case 82 and the terminals of the lower case 84 are prevented from contacting each other. The terminals 86 and 88 of the case 82 are bent toward each other along the outer side surface of the upper case 82 toward the center in the longitudinal direction of the upper case. The terminals 86 and 88 provided on the upper case 82 and the terminals 90 and 92 provided on the lower case 84 are soldered to the land portion of the board when the case containing the piezoelectric ceramic transformer is mounted on the board. To be fixed.

17 (a) to 17 (d) show an embodiment of a piezoelectric transformer assembly housed in such a case. FIGS. 17A and 17B are a schematic partially broken plan view and a partially broken side view, respectively, of an embodiment of the piezoelectric transformer assembly housed in the case shown in FIG. 14, and FIG. And (d) are CC line view and DD line arrow view of FIG.17 (b).
The piezoelectric transformer assembly 94 shown in FIGS. 17A to 17D is different from the holding member 52 (52a, 52b) in that the shape of the holding member 96 including the two holding bodies 97 is different. ) To (d) have the same configuration as that of the piezoelectric transformer assembly of the piezoelectric transformer unit 50. Therefore, the same components are denoted by the same reference numerals, and detailed description thereof is omitted. The holding member 96 will be basically described.

As shown in FIGS. 17A to 17D, the piezoelectric transformer assembly 94 includes the piezoelectric transformer 16 and two holding members 96 that hold the piezoelectric transformer 16. The holding member 96 is composed of two holding bodies 97. Each holding body 97 is made of a conductive material, and has a substantially trapezoidal cross-sectional shape and a U-shaped vertical cross-sectional shape as shown in FIGS. . That is, the holding body 97 has a shape such that its thickness becomes thinner from the center in the length direction of the piezoelectric transformer 16 toward the end. Here, two holding bodies 97 are used as a set, and the two holding bodies are arranged so as to face each other via the piezoelectric transformer 16.
In the embodiment shown in FIGS. 17A to 17D, two places in the longitudinal direction of the piezoelectric transformer 16 are held by holding members 96 each constituted by two holding bodies 97. In the illustrated example, the piezoelectric transformer 16 is held with respect to the case 80 by such a holding member 96. At this time, the holding body 97 is arranged so that the wide surface 97a of the holding body 97 is in contact with the input electrode of the piezoelectric transformer 16, and the narrower surface 97b of the holding body 97 is in contact with the inner surface of the fixing member. Further, since the holding member 96 in the illustrated example is configured to cover not only the upper and lower surfaces of the piezoelectric transformer 16 but also part of the side surfaces, the movement of the piezoelectric transformer 16 in the width direction is restricted.

  When the piezoelectric transformer assembly 94 is accommodated in such a case 80, each holding body 97 constituting the holding member 96 is exposed to the exposed portions 86 a and 86 a of the terminals 86 and 88 exposed inside the upper case 82. 88a and the exposed portions 90a and 92a of the terminals 90 and 92 exposed inside the lower case 84. Since each holding body 97 is made of a conductive material, by accommodating the piezoelectric transformer assembly 94 in the case 80 in this manner, the input electrodes 34a and 36a provided on one surface of the piezoelectric transformer 16 are The terminals 86 and 88 of the upper case 82 are energized, respectively. Also, the input electrodes 34b and 36b provided on the other surface of the piezoelectric transformer 16 are energized with the terminals 92 and 90 of the lower case 84, respectively. The piezoelectric transformer 16 is held between the exposed portions of the terminals provided on the upper case 82 and the lower case 84 and held in the case 80. The lower case 84 functions as a base of the piezoelectric transformer 16, and the upper case 82 functions as a fixing member for fixing the piezoelectric transformer 16 to the lower case 84 that is a base. The case 80 that houses the piezoelectric transformer assembly 94 is used by being mounted at a predetermined position on a substrate such as a wiring board or a printed board.

By the way, also in the present embodiment, as shown in FIGS. 17A, 17B, and 17C, the thermistor 58a is securely attached to the surface of the piezoelectric transformer 16, specifically, the upper surface of the second input electrode 36a. A concave portion is provided in the wide surface 97a of the holding body 97 on the upper side of the holding member 96 so as to be in contact with the holding member 96, and the holding member 96 is attached to be embedded in the concave portion.
On the other hand, as shown in FIGS. 17A, 17B, and 17D, the thermistor 58b is bonded to the upper surface of the narrower surface 97b of the holding body 97 on the upper side of the holding member 96 of the piezoelectric transformer 16. It is attached by etc. In this case, it is preferable to use a material having good thermal conductivity for the holding body 97 on the upper side of the holding member 96. In this case, the thermistor 58 b can be easily attached to the holding body 97 on the upper side of the holding member 96 of the piezoelectric transformer 16. Further, the mounting structure of the thermistor 58b may be a structure in which a recess is provided on the upper surface of the holding member 52 and the thermistor 58 is inserted therein.
In the illustrated example, the thermistor 58b is attached to the upper surface of the narrower surface 97b of the holding body 97. However, as in the case of the upper case 72 shown in FIGS. It may be attached to the exposed portion 86a of the terminal 86 exposed inside the upper case 82, which is in contact with the upper holding body 97, or the thermal conductivity of the upper case 82 to such an extent that the temperature of the piezoelectric transformer 16 can be measured. May be attached to the upper side surface of the upper case 82 facing the exposed portion 86a. Also in this case, the thermistor 58b can be easily attached.

Although the piezoelectric transformer device and the light source device using the same have been described in detail above, the present invention is not limited to this.
For example, in the above embodiment, the first output electrode 38 and the second output terminal 40 are formed on the end face of the piezoelectric ceramic 32 as shown in FIG. 2, but one end is provided like the piezoelectric transformer 16a shown in FIG. Electrodes 39a and 39b are respectively formed on the upper and lower surfaces of the electrode portion, electrodes 41a and 41b are respectively formed on the upper and lower surfaces of the other end portion, the electrodes 39a and 39b on the upper and lower surfaces of one end portion, and the other The electrodes 41a and 41b on the upper and lower surfaces of the end portions may be used as output electrodes. In the case of the piezoelectric transformer 16a, for example, as shown in FIGS. 5A and 5B, the electrodes 39a and 39b and the electrodes 41a and 41b formed on the upper and lower surfaces of both ends of the piezoelectric ceramic 32 are covered. The holding member 52 having the shape shown in the figure may be provided around. In this case, the holding member can be configured using an elastic material having conductivity. Therefore, if a land is provided on the substrate portion that receives the holding member 52, and a fixing member 56 as shown in FIG. 8 is arranged and energized, the output side wiring shown in FIG. Is effective against In addition, even in the case of the case, this configuration is applied to the output electrode of the piezoelectric transformer 16 having the structure shown in FIGS. 8, 9 and 17, and in the case of housing these piezoelectric transformer assemblies, By providing an electrode plate such as electrodes 86, 88, or 90, 92 shown in FIGS. 14 to 16 in any of the upper and lower cases corresponding to the holding member so as to be in contact with the provided holding member, It is possible to guide without a lead wire. This is effective in reducing the wiring “squeal” and the number of assembly steps. That is, by configuring in this way, no conductive wire is required in the output unit, and squeal due to the vibration of the electric wire is prevented not only in the input unit but also in the output unit.
Also in this case, the thermistor may be attached to the holding member, the fixing member, the upper case, etc. in the same manner as in the above-described example.

Moreover, in the said embodiment, although embodiment which accommodates a piezoelectric transformer assembly in the case comprised from an upper case and a lower case was shown, this invention is not limited to this.
For example, in the above-described embodiment, the two cases of the upper case and the lower case are used. However, a lower case (container) whose one surface is open and a lid member that covers the open surface are used. it can. In this case, the piezoelectric assembly may be accommodated in the lower case, and the open surface of the lower case may be covered with a lid member. In this case, the lid member functions as a fixing member. As a method of fixing the lid member provided on the open surface of the lower case to the lower case, a known fixing method such as a method of fitting a flat cover member into the open surface of the lower case or fixing by screws is used. Can do.

  In this case, the lower case may be configured to accommodate the whole or partially accommodate in the thickness direction of the piezoelectric transformer assembly. When the piezoelectric transformer assembly is partially accommodated in the lower case, instead of using a flat lid member as the fixing member, for example, a fixing member (sheet metal) having a shape as shown in FIG. 3 or FIG. 8 is used. Good. In this way, the piezoelectric transformer assembly can be partially accommodated in the lower case, and the piezoelectric transformer assembly can be fixed to the lower case using a fixing member similar to the fixing member 56 shown in FIG. 3 or FIG. That is, the fixing member as shown in FIG. 3 or FIG. 8 is disposed in close contact with the upper surface portion of the holding member disposed on the outer periphery of the piezoelectric transformer, and the leg portion of the fixing member is disposed on the side surface or upper portion of the lower case. The piezoelectric transformer assembly can be fixed to the lower case. Also in this case, the thermistor may be attached to the holding member and the fixing member in the same manner as in the above-described example.

Further, instead of the fixing member 56 shown in FIG. 3 or FIG. 8, a flat plate-like member (for example, FIG. 8 or the like) is used by using an upper case similar to the upper cases 72 and 82 shown in FIG. It is also possible to fix the piezoelectric transformer assembly to the substrate 54) shown. That is, a piezoelectric transformer assembly is arranged on a flat plate-shaped member, and an upper case (for example, an upper case as shown in FIG. 12 or FIG. 15) that can accommodate the piezoelectric transformer assembly is covered. Can be fixed to a flat plate-like member. In this case, the flat plate-like member may be a printed board or a flat plate on which no wiring or the like is formed. In this case, the flat plate-shaped member functions as a base, and the upper case functions as a fixing member. Further, the upper case may be configured such that the entire piezoelectric transformer assembly is covered or a part thereof is covered in the thickness direction of the piezoelectric transformer assembly.
Furthermore, in the present invention, as long as the holding member is disposed between the upper case and the lower case, the number of parts of the upper case and the lower case is not particularly limited, and the upper case or the lower case Can also be configured from a plurality of members. For example, the upper case or the lower case may be divided into two in the longitudinal direction of the piezoelectric transformer.
Also in these cases, the thermistor may be attached to the holding member, the upper case, or the like in the same manner as in the above-described example.

  In the embodiment described above, the piezoelectric transformer assembly in a state where the piezoelectric transformer is held by the holding member is housed in the case. However, the present invention is not limited to this, and the piezoelectric transformer unit in a state where the piezoelectric transformer assembly is attached to the substrate. May be stored in a case. As shown in FIGS. 3 and 8, such a method includes attaching the piezoelectric transformer assembly to the substrate 54 and then placing it in the case, and the above-described piezoelectric transformer 16a in the form of FIG. 18 at the output end (electrode 39a). , 39b and 41a, 41b), and a method of reducing the number of conductive wires, two methods are conceivable: attaching to the substrate and then placing in the case. In these methods, a hole for taking out a lead wire to the outside is provided on the side of the case and / or an electrode plate extending from the substrate is attached, and a gap through which the electrode plate is passed is provided between the upper case and the lower case. This is possible. In these cases, a thermistor can be attached as in the above-described various embodiments, but the conductor from the thermistor is a gap through which the electrode connecting lead for the piezoelectric transformer and the electrode plate pass. Or may be taken out from a dedicated hole or gap formed separately.

Specifically, like the piezoelectric transformer unit 50 shown in FIG. 3, the piezoelectric transformer 16 fixed to the substrate 54 by the fixing member 56 and the holding member 52 can be housed in a case and used. In this case, the case is configured to have such dimensions that the piezoelectric transformer unit 50 fixed to the substrate 54 is accommodated. In addition, even if the case is configured by combining two cases, an upper case and a lower case, by combining a lower case with one surface opened and a lid member on a flat plate covering the open side of the lower case It may be configured.
Further, when the piezoelectric transformer fixed to such a substrate is accommodated in the case, a hole for taking out the conductive wire connected to each electrode of the piezoelectric transformer is formed on the side surface of the case. be able to.

Further, as in the piezoelectric transformer unit 51b shown in FIG. 8, the piezoelectric transformer 16 fixed to the substrate 54 by the fixing member 56 and the holding body 67 can also be accommodated in the case and used. Also in this case, the case may be configured to have a size such that the piezoelectric transformer unit 51b fixed to the substrate 54 is accommodated, and may be configured by combining two cases of an upper case and a lower case. You may comprise by combining the lower case where one surface was open | released, and the lid member on the flat plate which covers the open side of the lower case. In the example shown in FIG. 8, the holding body 67 of the holding member 66 is made of a conductive material, and the substrate 54 has land portions corresponding to the input electrodes 34 a and 36 a and the output electrodes 34 b and 36 b of the piezoelectric transformer 16. 68a to 68h are provided. When the land portions are provided on the substrate as described above, metal electrode plates can be formed so as to extend from the respective land portions, and the respective electrode plates can be taken out of the case. As a method of taking out each electrode plate into the case, for example, when the case is composed of an upper case and a lower case, a gap is provided between the upper case and the lower case, and each electrode plate is opened from the gap. It is possible to use a method of taking out the case from the case. If the case is composed of a lower case and a lid member, use a method in which a gap is provided between the lower case and the lid member, and each electrode plate is taken out of the case from the gap. can do.
It is also possible to provide a hole on the side surface of the case without providing an output land on the substrate, and to take out the conductive wire connected to the output electrode from the hole.

  In addition, when the output electrodes are formed on the upper and lower surfaces of both ends of the piezoelectric transformer as shown in FIG. 18, a plurality of holding bodies (hereinafter referred to as the following) disposed on the surface of each input electrode of the piezoelectric transformer of FIG. Similarly to the first holding body), a plurality of holding bodies of conductive material (hereinafter referred to as second holding bodies) are also provided on the surfaces of the output electrodes arranged above and below the both ends. The piezoelectric transformer can be fixed to the substrate by the fixing member while the two holding bodies are interposed between the fixing members. In this case, the first land portion for the output electrode is formed on the substrate so as to contact the second holding body on the side facing the substrate, and the substrate can be soldered by contacting the leg portion of the fixing member. A second land portion for another output electrode can be formed.

In addition, the piezoelectric transformer fixed to the substrate in this way can also be used by being housed in the case. Also in this case, the case is configured to have such a dimension that the piezoelectric transformer unit fixed to the substrate is accommodated. Further, as described above, the case may be configured by combining two cases of the upper case and the lower case, or on the flat plate that covers the lower case with one surface opened and the open side of the lower case. You may comprise by combining with a cover member. Further, in this case, similarly to the land portion for the input electrode, a metal electrode plate is formed so as to extend from the first land portion and the second land portion for the output electrode, respectively, and each electrode plate is formed as a case. It can be configured to be taken out of.
In addition, as a method of taking out each electrode plate outside the case, for example, when the case is composed of an upper case and a lower case, a gap is formed between the upper case and the lower case, as described above. The method of providing and taking out each electrode plate out of the case from the clearance can be used. Further, when the case is composed of a lower case and a lid member, a method is provided in which a gap is provided between the lower case and the lid member, and each electrode plate is taken out of the case from the gap. Can also be used.

  In the present invention, instead of the holding body 67 shown in FIGS. 9A and 9B, as shown in FIG. 19, a pair of holding bodies 98 each having two protrusions (bosses) 98a are used. A holding member can be used. In the case of the piezoelectric transformer unit 51c using such a holding member made up of a pair of holding bodies 98, like the fixing member 62 of the piezoelectric transformer unit 51a shown in FIG. A fixing member 62 in which a matching through hole 62a is formed can be used. Here, in this embodiment, the thermistor 58a is attached to the inner side of the upper holding body 98 (the side in contact with the piezoelectric transformer 16), as in the other embodiments. May be attached to the upper surface of the fixing member 62, or may be attached to the protrusion 98a of the upper holding body 98, although not shown. Moreover, the holding body 98 can be comprised from an electroconductive material similarly to the holding member 67 shown in FIG. As the substrate 55 for mounting the piezoelectric transformer assembly including the holding body 98, as in the substrate 54 of the piezoelectric transformer unit 51b shown in FIG. 8, a land (not shown) is in contact with the holding body 98 disposed on the substrate 55 side. The substrate on which (a) is formed can be used. In addition, a through hole 55 a is formed in the land portion of the substrate 55 so as to be fitted to the protruding portion 98 a of the lower holding body 98. In this manner, the piezoelectric transformer assembly is mounted on the substrate by the fixing member 62 via the holding body 98 in a state where the protrusion 98 a of the holding body 98 is fitted into the through hole 62 a of the fixing member 62 and the through hole 55 a of the substrate 55. By fixing to 55, the displacement of the piezoelectric transformer 16 can be further prevented as compared with the configuration shown in FIGS. Here, the number of the protrusions 98a of the holding body 98 is two, but it may be one or three or more.

Further, in the piezoelectric transformer unit 51c shown in FIG. 19, the holding body arranged on the substrate side and the holding body arranged on the opposite side are configured by holding bodies having the same shape, but they are held in different shapes. It can also consist of a body. FIG. 20 schematically shows a cross-sectional structure of a piezoelectric transformer unit 51d using a holding member composed of a pair of holding bodies 100 and 102 formed in different shapes. In the piezoelectric transformer unit 51 d shown in FIG. 20, a piezoelectric transformer assembly including a holding member including a pair of holding bodies 100 and 102 formed in different shapes is attached to a substrate 55 by a fixing member 56.
As shown in FIG. 20, the first holding body 102 disposed on the substrate 55 side includes two protrusions 102a, like the holding body 98 shown in FIG. Moreover, the 2nd holding body 100 arrange | positioned on the opposite side has a U-shaped longitudinal cross-sectional shape similarly to the holding body 97 shown in FIG.17 (c). In the transformer unit 51d shown in FIG. 20, since the upper part of the side surface of the piezoelectric transformer 16 is held by the edge portion 100a of the holding body 100, displacement of the piezoelectric transformer 16 in the width direction (left-right direction in the figure) is prevented. Is done. Also in the embodiment shown in FIG. 20, a protrusion may be provided on the upper surface of the second holding body (the surface in contact with the fixing member 56) in the same manner as the holding body 98 shown in FIG. 19.
In the present embodiment, the thermistor 58a is attached to the inner side of the upper holding body 100 (the side in contact with the piezoelectric transformer 16), as in the above-described embodiment. You may attach to the upper surface of 56.

Moreover, in the said embodiment, the cross-sectional shape is substantially trapezoid like the holding member 52 shown in FIG.5 (b), or the holding body 67 of the holding member 66 shown in FIG.8 and FIG.10, and it is from a center part. It is comprised so that it may become a shape like the mountain hem where thickness becomes thin gradually toward the both sides of the width direction. That is, in the holding member 52 shown in FIG. 5B, the inner wall surface 53b in contact with the piezoelectric transformer 16 is formed wider than the outer peripheral surface 53c, and the thick portion 53d having a constant thickness. And a thin-walled portion (tapered portion) 53e that is located on both sides of the thick-walled portion 53d and becomes thinner toward the outer side in the width direction. However, in the present invention, the shape of the holding member is not limited to this.
For example, as shown in FIG. 21, in the cross-sectional shape, the inner wall surface (lower surface in the figure) 104b that contacts the piezoelectric transformer 16 is wider than the outer outer wall surface (upper surface in the figure) 104c. A thick portion 104d having a constant thickness and a thin portion (tapered portion) 104e which is located on one side of the thick portion 104d and becomes thinner toward the outer side in the width direction. The holding member 104 can also be used. The side surface 104g of the thick portion 104d of the holding member 104 is formed perpendicular to the inner wall surface 104b and the outer wall surface 104c, and the inclined surface 104f of the taper portion 104e is formed as a concave curved surface. In FIG. 21, the inclined surface 104f of the tapered portion 104e is configured by a curved surface, but may be configured by a plane. Further, the side surface 104g of the thick portion 104d of the holding member 104 may not be perpendicular to the inner wall surface 104b and the outer wall surface 104c, and may be inclined.

Further, when the holding members 104 having the shape shown in FIG. 21 are provided at two locations in the length direction of the piezoelectric transformer 16, the side surfaces 104g of the thick portion 104d of the holding member 104 face each other, or a tapered portion. It is preferable to provide each so that 104e may face each other.
In the present invention, the holding member 104 having the cross-sectional shape shown in FIG. 21 is circulated around the piezoelectric transformer 16 as shown in FIG. 5A, the holding members 52, 60 and 64 shown in FIGS. As shown in FIG. 8, the holding member 67 of the holding member 66, the holding member 97 of the holding member 96 shown in FIG. 17, the holding member 98 of the holding member shown in FIG. The cross-sectional shape of the holding members 100 and 102 of the holding member shown may be the shape shown in FIG.

  Further, in the holding member 52 having the tapered portions 53e on both sides of the thick wall portion 53d shown in FIG. 5B, the angles of the inclined surfaces of the tapered portions 53e on both sides may be changed. That is, you may comprise so that the inclination angle of the inclined surface of one taper part 53e and the inclination angle of the inclined surface of the other taper part 53e may mutually differ. Moreover, the inclined surface of one taper part can be comprised by a curved surface, and the other inclined surface can also be comprised by a plane. The holding members 60 and 64 shown in FIGS. 6 and 7 and the holding bodies 67, 97, 98, 100, and 102 shown in FIGS. 8, 10, 17, 19 and 20 have the same configuration. Of course.

In the present invention, as described above, a columnar piezoelectric ceramic may be used instead of a plate-shaped piezoelectric ceramic as the piezoelectric ceramic of the piezoelectric transformer. For example, the cross-sectional shape perpendicular to the axis is square or circular. Although piezoelectric ceramics having a shape such as an ellipse can also be used, the piezoelectric transformer unit shown in FIGS. 3 to 10 and the piezoelectric transformer unit shown in FIGS. It can be set as the structure similar to a piezoelectric transformer assembly and a piezoelectric transformer, and the same effect can be acquired.
The piezoelectric transformer used in the piezoelectric transformer unit of the present invention is not limited to the piezoelectric transformer having the above structure. For example, a Rosen transformer, a piezoelectric transformer using a lateral effect, a surface vibration piezoelectric transformer, a central drive piezoelectric transformer, a block Piezoelectric transformers such as a piezoelectric transformer, a laminated piezoelectric transformer, a central output piezoelectric transformer, a multi-output piezoelectric transformer, a piezoelectric transformer using a higher-order mode, a bolt-clamped piezoelectric transformer, and an array-type piezoelectric transformer can be used.

  As described above, in the present invention, the holding member or the holding member that sandwiches the piezoelectric transformer between the two holding bodies from both sides is provided on the outer periphery of the piezoelectric transformer, and the width of the holding member becomes narrower as the distance from the piezoelectric transformer increases. Therefore, when the piezoelectric transformer is fixed by the fixing member via the holding member, the piezoelectric transformer is prevented from being displaced from the fixing member and the base such as the substrate. Therefore, the piezoelectric transformer unit used in the present invention can be stably fixed on the substrate even if it vibrates during driving.

  The piezoelectric ceramic transformer device of the present invention and the light source device using the same have been described with reference to various embodiments and examples. However, the present invention is not limited to these embodiments and examples, and the gist of the present invention. It goes without saying that various improvements or changes may be made without departing from the scope of the invention.

(A) And (b) is a block diagram which shows the outline of one Embodiment of the light source device of this invention using the piezoelectric ceramic transformer apparatus of this invention, respectively, and explanatory drawing which shows a circuit block structure. It is a typical perspective view of one Embodiment of the piezoelectric ceramic used for the piezoelectric ceramic transformer apparatus shown in FIG. It is a typical perspective view which shows the schematic structure of one Embodiment of a piezoelectric ceramic transformer unit provided with the piezoelectric ceramic transformer shown in FIG. 2, its holding mechanism, and a temperature detection device. (A) and (b) are respectively a schematic partially broken plan view and a partially broken side view of the piezoelectric ceramic transformer unit shown in FIG. 3, and (c) and (d) are C- It is a C line and DD line arrow directional view. (A) And (b) is a typical side view and typical sectional view of a holding member shown in Drawing 3, respectively. It is a typical partial exploded cross-sectional view of another embodiment of the piezoelectric ceramic transformer unit used in the present invention. It is a typical cross-sectional view of another embodiment of the holding member used in the present invention. It is a typical partial exploded cross-sectional view of another embodiment of the piezoelectric ceramic transformer unit used in the present invention. (A) is a schematic side view of the piezoelectric ceramic transformer unit shown in FIG. 8, respectively. (B) and (c) are the BB line and CC line arrow views of (a). is there. It is a typical perspective view of the holding member shown in FIG. It is a schematic perspective view of one Embodiment of the case which accommodates the piezoelectric ceramic transformer used for this invention. It is a schematic perspective view of the upper case of the case shown in FIG. It is a schematic perspective view of the lower case of the case shown in FIG. It is a schematic perspective view of another embodiment of the case which accommodates the piezoelectric ceramic transformer used for this invention. It is a schematic perspective view of the upper case of the case shown in FIG. It is a schematic perspective view of the lower case of the case shown in FIG. (A) and (b) are respectively a schematic top view and a schematic side view of an embodiment of a piezoelectric ceramic transformer assembly housed in the case shown in FIG. 14, and (c) and (d) are ( It is the CC line and DD line arrow figure of b). It is a schematic perspective view of another embodiment of the piezoelectric ceramic transformer used in the present invention. FIG. 6 is a schematic partially exploded cross-sectional view of still another embodiment of a piezoelectric ceramic transformer unit used in the present invention. FIG. 6 is a schematic partially exploded cross-sectional view of still another embodiment of a piezoelectric ceramic transformer unit used in the present invention. It is a typical cross-sectional view of another embodiment of the holding member used in the present invention.

Explanation of symbols

10 Light source device 11 Piezoelectric ceramic transformer device (piezoelectric transformer device)
12 Power supply 14 Drive unit 16, 16a Piezoelectric ceramic transformer (piezoelectric transformer)
18 Light Emitting Unit 18a Cold Cathode Tube (CCFL)
20 tube current detection circuit 22 temperature detection device 24 voltage control oscillation circuit 26 oscillation unit 28 protection circuit 30 drive circuit 32 piezoelectric ceramic 32a first region 32b second region 32c third region 32d fourth region 32e fifth region 34a, 34b first 1 input electrode 36a, 36b 2nd input electrode 38 1st output electrode 39a, 39b, 41a, 41b electrode 40 2nd output electrode 42a, 42b, 44a, 44b Input terminal 46, 48 Output terminal 50, 51a, 51b, 51c, 51d Piezoelectric ceramic transformer unit 52, 52a, 52b, 60, 64, 66, 66a, 66b, 96, 104 Holding member 54, 55 Substrate 56, 56a, 56b, 62 Fixing member 58, 58a, 58b Thermistor 67, 97, 98 , 100, 102 Holder 68a, 68b, 68c, 68d, 68 e, 68f, 68g, 68h Land 70, 80 Case 72, 82 Upper case 74, 84 Lower case 72a, 74a Recess 74b, 74c, 74d, 74e Groove 76 Screw holes 86, 88, 90, 92 Terminals 86a, 88a Exposed Part 94 Piezoelectric ceramic transformer assembly (piezoelectric transformer assembly)

Claims (12)

A piezoelectric ceramic transformer that outputs a secondary AC signal based on the input primary AC signal;
A drive unit for inputting the primary AC signal to the piezoelectric ceramic transformer;
Temperature detecting means for detecting the temperature of the piezoelectric ceramic transformer;
A piezoelectric ceramic transformer device comprising: a protection circuit that restricts the output of the primary side AC signal by the drive unit in accordance with the temperature detected by the temperature detection means.   The piezoelectric ceramic transformer device according to claim 1, further comprising a holding member for the piezoelectric ceramic transformer, a base, and a fixing member for fixing the holding member to the base.   3. The piezoelectric ceramic transformer device according to claim 2, wherein the holding member is made of an elastic material having a trapezoidal shape or a substantially trapezoidal shape in a side ridge shape.   The piezoelectric ceramic transformer device according to claim 2 or 3, wherein the holding member holds a position of a vibration node of the piezoelectric ceramic transformer.   5. The piezoelectric ceramic transformer device according to claim 2, wherein the temperature detection unit is attached so as to be in direct contact with the piezoelectric ceramic transformer between the piezoelectric ceramic transformer and the holding member.   6. The piezoelectric ceramic transformer device according to claim 2, wherein the temperature detection unit is embedded and held in the holding member and is attached so as to be in direct contact with the piezoelectric ceramic transformer. The holding member and the fixing member are each a heat conductive member,
The piezoelectric ceramic transformer device according to claim 2, wherein the temperature detection unit is fixed on the fixing member.   The piezoelectric ceramic transformer device according to claim 1, wherein the temperature detection means is a thermistor. A piezoelectric ceramic transformer device according to any one of claims 1 to 8,
A light source device comprising: a discharge tube connected to an output side of the piezoelectric ceramic transformer and emitting light by driving the piezoelectric ceramic transformer. Furthermore, a tube current detection circuit for detecting a tube current flowing through the discharge tube when the discharge tube emits light,
The light source device according to claim 9, further comprising: a voltage-controlled oscillation circuit that generates a signal having an oscillation frequency controlled according to the tube current detected by the tube current detection circuit. The discharge tube is a plurality of cold cathode discharge tubes,
The light source device according to claim 10, wherein the tube current detection circuit detects a total current of the tube currents flowing through the plurality of cold cathode discharge tubes emitting light.   The light source device according to claim 9, wherein the light source device functions as a planar illumination device having a planar light exit surface.

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