KR20000076818A - Transformer - Google Patents

Abstract

A voltage converter comprising a core having dielectric and magnetic properties, a line conductor and a ground conductor constituting the transmission line, wherein the line length L of the transmission line is equal to 1/4 wavelength on the transmission line at an operating frequency. A transformer set almost equally, having a line converter and a ground conductor constituting a transmission line, and a voltage converting portion comprising a core having dielectric and magnetic properties, wherein the line length L of the transmission line is 1 / l of the transmission line at the operating frequency. Since the grounding conductor is set almost equal to 4 wavelengths, the grounding conductor is formed between the core and the line conductor, so that even if the line conductor is densely arranged, it functions as a distributed constant circuit, and can be made smaller and thinner. Transformers with higher boosting ratio and higher conversion efficiency by avoiding losses, and also simplify configuration The.

Description

Transformers {TRANSFORMER}

The present invention relates to a transformer that can be preferably used for an inverter for a backlight of a liquid crystal display device.

In general, it is known that a backlight inverter of a liquid crystal display device is provided with a boost transformer. As a boost transformer used for such a use, a winding transformer is conventionally used. This winding transformer is connected to a cold cathode tube via a ballast capacitor. Mercury is enclosed in this cold cathode tube, and electrons generated by applying a high voltage impinge on the mercury to generate ultraviolet rays. The ultraviolet rays are excited to emit phosphors coated on the inside of the tube and are converted into visible light. Such a cold cathode tube needs to be applied with a high voltage in order to generate electrons at start-up. However, once the discharge is started, the voltage holding the discharge may be about 1/3 of the starting voltage. At this time, it is enough to flow a current of about 5 to 6 mA into the cold cathode tube, and no large current is required. Therefore, the characteristics required for the boost transformer used for such a purpose are that the output voltage can be instantaneously increased at the start of discharge of the cold cathode tube, and can be reduced to the discharge holding voltage at normal time.

However, in recent years, the demand for miniaturization and high performance of the liquid crystal display device is increasing, and in order to satisfy such a demand, miniaturization, thinning, and high conversion efficiency of the backlight inverter have been strongly desired.

However, the conventional inverter has a problem in that the conversion efficiency is lowered when the thinning is realized by using the winding transformer. The reason is that flattening the core shape to make the winding transformer thinner results in a longer winding and an increase in DC resistance. In addition, in the case of using the winding transformer, the installation area becomes large, which limits the miniaturization.

Thus, an inverter for backlight having a piezoelectric transformer composed of a flat plate ceramic element instead of a winding transformer has been considered. Although the piezoelectric transformer can be thinned while maintaining high conversion efficiency, the winding transformer is sometimes used as an auxiliary transformer due to the lack of a boosting ratio, thereby limiting the thinning. In addition, since the boosting ratio and the resonance frequency of the piezoelectric transformer are determined by the shape of the device and the coupling coefficient of the electric device, if the size of the device is reduced, the resonance frequency shifts to the high frequency side and the boosting ratio is also reduced. Since it was not possible to make it small, the equipment area became large, similar to the winding transformer, and there was a limitation in miniaturization of the inverter. In addition, in the piezoelectric transformer, in order to make both the high voltage raising ratio and the high conversion efficiency compatible, the piezoelectric transformer needs to have a laminated structure or a rectangular shape having a long side of 20 to 30 mm, which makes the structure relatively complicated.

On the other hand, as a transformer using an impedance conversion action, there has been reported an example of using a high frequency coaxial cable as a distributed constant line for a lighting device of a discharge lamp and using the high frequency coaxial cable as a voltage converter. As an insulator of this coaxial cable, polyethylene (ε = 2.3) and Teflon (ε = 2.1) are usually used depending on the frequency of use.

However, in the conventional transformer, the dielectric constant of the coaxial cable insulator is low, and for example, in order to use at 1 MHz, the length of the coaxial cable needs to be about 49 m, especially about 60 mW when used as a backlight inverter of a liquid crystal display device. In order to use, it is necessary to make the coaxial cable length about 884 m, and it was difficult to miniaturize.

As means for solving the above problems, the following transformers have been proposed. This transformer obtains a high voltage by using a voltage / current distribution when tuning a quarter-wave transmission line terminated with high resistance.

6 is a schematic block diagram showing an example of such a transformer. This transformer has a pair of cores 84 and 84 having dielectric and magnetic properties, and a spiral coil inner conductor 91 formed between these cores 84 and 84 and a coil type formed outside the cores 84 and 84. Or a cold cathode tube (loading device) 120 having a voltage conversion section 102 having a transmission line 100 made of film type outer conductors 92 and 92 and an impedance different from the inherent impedance of the voltage conversion section 102. It is provided.

Of the pair of cores 84, 84, the core 84 on the upper side of the inner conductor 91 is divided left and right to take out the connecting terminal.

Ferrite or the like is used as a material for forming the pair of cores 84 and 84.

An insulator 85 is interposed between the inner conductor 91 and each core 84.

Between the inner conductor 91 and the insulator 85 above it, between the insulator 85 and the core 84 above it, between the core 84 and the outer conductor 91 above it, respectively. The adhesive layer 86 is interposed. In addition, an adhesive layer 86 is interposed between the insulator 85 under the inner conductor 91 and the core 84 under the inner conductor 91, and between the core 84 and the outer conductor 92 under the inner conductor 91. It is.

The cold cathode tube 120 is connected to the output side (receive end side) terminal of the inner conductor 91, and the switch circuit 135 connected to an AC power supply (not shown) is connected to the input side (transmission end side) terminal.

The cold cathode tube 120 is connected to the output side (receive end side) terminal of the external conductor 92, and the switch circuit 135 connected to the said AC power supply (not shown) is connected to the input side (transmission end side) terminal.

The outer conductors 92 and 92 are electrically connected by the connecting conductor 93 in order to make the potential equal.

The line length L of the transmission line 100 has a length substantially equal to a quarter wavelength of the frequency of the voltage applied to the transmission line 100.

The transformer of such a configuration can increase both the permeability and the permittivity of the portion where the electromagnetic field of the transmission line 100 is generated by the dielectric properties and magnetism of the core 84, and as a result, a high wavelength shortening effect can be obtained, and thus a short line length 1/4 wavelength line can be constructed.

By the way, in the transformer shown in Fig. 6, the wavelength can be shortened by the dielectric properties and magnetism of the core 84, so that the core dimensions can be shortened, so that the installation area can be small, thereby maintaining high boost ratio and high conversion efficiency. Although it is possible to miniaturize in the state, there have been complaints as described below.

In the transformer shown in Fig. 6, since a portion in which a high frequency electric field is generated by the transmission line 100, that is, a core 84 made of ferrite or the like is interposed between the inner conductor 91 and the outer conductor 92, the transmission line When high frequency voltage is applied to (100), a loss occurs and the conversion efficiency (trans characteristic) is lowered, which has been an obstacle to realizing a transformer having a higher conversion efficiency. This is because each core 84 has a low resistance to be used as an insulator at a high frequency, and when a high frequency voltage is applied to the transmission line 100, current flows to each core 84 to cause a loss.

In the transformer, the capacitance between the inner conductor and the outer conductor was controlled to give a characteristic impedance to function as a transducer element. In the transformer shown in Fig. 6, the inner conductor 91 is densely arranged to further reduce the size. There has been a problem that the capacitance between the mutual conductors of the inner conductor 91 becomes large and does not function as a distributed constant circuit. This is because the capacitance in the transformer shown in FIG. 6 depends on the core 84 and the insulator 85 between the inner conductor 91 and the outer conductor 92.

A transformer having a conductive and magnetic core and a transmission line, the wavelength shortening effect can be obtained by the permittivity and permeability of the core, the core size can be shortened, and the miniaturization can be made a transmission line type transformer.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows roughly the structure of the transformer of 1st Embodiment of this invention.

FIG. 2 is a plan view showing the main part of the transformer shown in FIG. 1; FIG.

3 is a diagram for explaining a distribution constant circuit of the transformer of the first embodiment.

Fig. 4 is a diagram for explaining the step-up action of the transmission line of the transformer of the first embodiment.

5 is a diagram showing a schematic configuration of a transformer of a second embodiment of the present invention.

6 is a diagram showing a schematic configuration of a conventional transformer.

※ Explanation of codes for main parts of drawing

2: voltage conversion unit 4: core

6a: first adhesive layer 6b: second adhesive layer

6c: third adhesive layer 10: transport line

20: cold cathode tube (load device) 41: track conductor

41a: output terminal 41b: input terminal

42: grounding conductor 43: connecting conductor

45: insulation layer (insulator)

The present invention has been completed in view of the above circumstances, and includes a voltage converting unit comprising a core having dielectric properties and magnetism, a line conductor and a ground conductor constituting a transmission line, and the line length L of the transmission line operates. In the transformer set almost equal to one-quarter wavelength on the transmission line at the frequency, even if the conductors are densely arranged, they function as distributed constant circuits, can be made smaller and thinner, and the high frequency voltage is applied to the core. It is an object of the present invention to provide a transformer in which a boosting ratio can be made higher by preventing a loss caused, a conversion efficiency can be made higher, and a structure can be simplified.

The transformer according to the present invention has a voltage converting portion comprising a line conductor and a ground conductor constituting a transmission line, and a core having dielectric and magnetism, wherein the line length L of the transmission line is on the transmission line at an operating frequency. It is set almost equal to a quarter wavelength and the ground conductor is formed between the core and the line conductor.

According to the transformer of the present invention, there is provided a voltage converting unit comprising a line conductor and a ground conductor constituting a transmission line, and a core having dielectric and magnetic properties, wherein the line length L of the transmission line is on the transmission line at an operating frequency. In a transformer set almost equal to a quarter wavelength, the ground conductor is formed between the core and the line conductor, so that a core having dielectric properties and magnetism is formed at a portion where a high frequency electric field is not generated by a transmission line. Even when a high frequency voltage is applied to the transmission line, voltage is not applied to the core, thereby preventing a loss due to voltage on the core, and a voltage raising ratio can be sufficiently high, and conversion efficiency can be higher.

In addition, the transmission line transformer can shorten the wavelength due to the effects of both the dielectric and magnetic properties of the core, thereby shortening the core dimension. In the present invention, since the core is disposed at the portion where the magnetic field is generated by the transmission line, the wavelength shortening effect due to the high permeability can be obtained. In addition, since there is no core in the portion where an electric field is generated by the transmission line, the wavelength shortening effect due to the high dielectric constant is not expected. However, in the transformer shown in FIG. 6, a low dielectric constant polyimide (ε = 4) is formed between the core and the inner conductor. Insulators are arranged so that most of the electric field is placed thereon, and the effects of the dielectric properties of the core do not all appear. The wavelength shortening effect is mainly due to the high permeability of the cores. The reduction of the wavelength shortening effect due to the change out of the conductor is small.

In the converter according to the present invention, since a core is not interposed between the line conductor and the ground conductor, the dielectric constant of the core does not affect the capacitance between the line conductor and the ground conductor, and between the line conductors and each other. The capacitance of the core does not affect the capacitance. Therefore, even if the line conductor is densely arranged and downsized, the capacitance between the line conductors and each other can be prevented from increasing relatively to the capacitance between the line conductor and the ground conductor, so that it can function as a distributed constant circuit. .

Therefore, according to the present invention, even if the line conductor is densely arranged, it functions as a distributed constant circuit, can be further miniaturized and thinned, and can prevent the loss caused by voltage being applied to the core to increase the boost ratio. It is possible to provide a transformer with which the structure can be made higher and the structure can be simplified.

In the transformer according to the present invention, the line conductor may be formed in a planar shape, the ground conductor may be laminated on at least one surface of the line conductor through an insulator, and the core may be stacked on the ground conductor. .

In the transformer according to the present invention, it is preferable that a load device having an impedance different from the inherent impedance of the voltage modifying portion is provided.

In the transformer according to the present invention, the insulator is preferably made of a material having an effective dielectric constant? According to such a transformer, the capacitance between the line conductor and the ground conductor is determined only by the insulator, and the capacitance between the line conductors and the mutual conductors is equal to the capacitance between the line conductor and the ground conductor even when the conductor is densely arranged. Since it can prevent that it becomes relatively large, it can function as a distributed constant circuit.

Moreover, in the modification machine which concerns on this invention, the said core may consist of 1 type (s) or 2 or more types chosen from Mn-Zn ferrite, Ni-Zn ferrite, Ni-Cu ferrite. According to such a transformer, the size of the core can be shortened and miniaturization is possible.

In the transformer according to the present invention, it is preferable that the core has an effective permeability (μ) of 10 to 20,000 and an effective dielectric constant (ε) of 10 to 5000 at 100 kPa. Since the wavelength shortening effect increases as the effective permeability (μ) and the effective dielectric constant (ε) increase, the transformer can be miniaturized. However, the characteristic impedance of the transmission line increases as the effective permeability (μ) increases, but decreases as the effective dielectric constant (ε) increases, so an optimal range exists for μ and ε. Therefore, in the present invention, in order to increase the wavelength shortening effect and set the characteristic impedance to a predetermined value, mu and ε are preferably in the above ranges.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this transformer of this invention is described.

In the embodiment described below, the case where the transformer of the present invention is applied to a backlight inverter of a liquid crystal display device will be described.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the transformer of 1st Embodiment of this invention, and FIG. 2 is a top view which shows the principal part of the transformer of this 1st Embodiment.

The transformer of this first embodiment is schematically composed of a voltage converter 2 having cores 4 and 4 formed outside the transmission line 10 and a cold cathode tube 20 functioning as a load device.

The voltage converter 2 has ground conductors 42 and 42 formed on opposing surfaces of the pair of cores 4 and 4 facing each other, and an insulating layer (insulator) inside the ground conductors 42 and 42, respectively. 45, 45 are formed, and the track conductor 41 is formed inside the insulating layers 45, 45 again. In the first embodiment, the transmission line 10 is constituted by the line conductor 41 and the ground conductors 42 and 42 above and below.

A first adhesive layer 6a is interposed between the opposing surfaces of the pair of cores 4 and 4 and the ground conductor 42, and a second adhesive layer () between the ground conductor 42 and the insulating layer 45. 6b) is interposed, and the 3rd contact bonding layer 6c is interposed between the track conductor 41 and this upper insulating layer 45. As shown in FIG.

The pair of cores 4 and 4 are dielectric and magnetic. As the furnace constituting each core 4, one or two or more selected from the group consisting of Mn-Zn ferrite, Ni-Zn ferrite, and Ni-Cu ferrite can be used to shorten the dimensions of the core, thereby modifying the transformer. It is preferable in that it can be miniaturized.

Each core 4 is preferable for the reason described above that the effective permeability (μ) at 100 kPa is 10 to 20000, and the reason described above that each core 4 has an effective dielectric constant (ε) of 10 to 5000. It is preferable because of that.

The line conductor 41 is a spiral coil type.

The ground conductors 42 and 42 may be spiral coiled or may be a film (planar) formed on the entire opposite surface of the cores 4 and 4.

The capacitance between the line conductor 41 and the ground conductors 42 and 42 is preferably sufficiently large with respect to the capacitance between the line conductors 41 and each other, and preferably at least equal. This capacitance depends on the line width and spacing of the line conductor 41 and the thickness of each insulating layer 45.

Each insulating layer 45 is comprised with polyimide of (epsilon) = 4.

If the thickness of each insulation side 45 is too thick, the capacitance between the line conductor 41 and the ground conductors 42 and 42 becomes small, and if the thickness is too thin, the capacitance becomes large.

The cold cathode tube 20 is connected to the output side (receive end side) terminal 41a of the line conductor 41 as mentioned above, and the switch connected to an AC power supply (not shown) to the input side (transmission end side) terminal 41b. The circuit 35 is connected. In addition, a cold cathode tube 20 is connected to an output terminal of one of the drawing conductors (a grounding conductor located below the line conductor 41; 42), and a switch circuit 35 connected to the AC power source is connected to the input terminal. Is connected. In addition, one grounding conductor (the grounding conductor located below the line conductor 41; 42) is electrically connected by the connecting conductor 42 so as to make the potential equal.

The line length L of the transmission line 10 consisting of the line conductor 41 and the ground conductors 42, 42 is 1 / of the transmission line 10 at the frequency (operating frequency) of the alternating current applied to these conductors. It is set almost equal to four wavelengths. In the first embodiment, the length of the line conductor 41 is set almost equal to 1/4 wavelength on the transmission line at the operating frequency.

Cold cathode tube 20 having an impedance greater than the natural impedance of voltage converter 2 if line length L of transmission line 10 is not approximately equal to a quarter wavelength on transmission line 10 at the operating frequency. In this case, impedance conversion and voltage conversion are not performed, which is undesirable.

As the cold cathode tube 20, the one having an impedance different from the natural impedance of the voltage conversion section 2 having the above-described configuration is used at a magnification according to the ratio of the natural impedance of the voltage conversion section 2 at both ends of the load. It is preferable in that a voltage different from the input voltage is applied. In addition, the cold cathode tube 20 having an impedance larger than the intrinsic impedance of the voltage converter 2 is higher than the input voltage at a magnification according to the ratio with the intrinsic impedance of the voltage converter 2 at both ends of the load. More preferred is that a voltage is applied.

In the transformer of the first embodiment having the above-described configuration, a pair of cores 4 and 4 having dielectric and magnetic properties and a transmission line 10 are inputted by inputting a parasitic capacitance (distribution constant) into a circuit constant. The distributed constant circuit as shown in 3 is comprised. In Fig. 3, symbol V ₁ is an input voltage, V ₂ is a receiving terminal voltage, I ₁ is an input current, I ₂ is a receiving terminal current, Z ₁ is an impedance seen from the input side, Z ₂ is an impedance seen from the output side, and Z ₀ is a transmission line. The intrinsic impedance of L is the line length of the transmission line.

The distributed constant circuit shown in FIG. 3 is represented by following formula (1).

Equation (1)

Where V ₁ is the input voltage, V ₂ is the receiving end voltage, I ₁ is the input current, I ₂ is the receiving end current, Z ₀ is the inherent impedance of the transmission line, L is the line length of the transmission line, and β is the line (10 ) Is a first half constant (β = 2πf / v = 2π / λ · (1-a) expression). In the formula (1-a), v is the propagation velocity (= fλ), and λ is the propagation wavelength.

In this embodiment, since the line length L of the transmission line is λ / 4 on the transmission line at the operating frequency,

βL = (2π / λ) × (λ / 4) = π / 2

Becomes

Therefore, Formula (1) is represented by following formula (4).

Equation (4)

By changing the above equation (4) to find the impedance (Z ₁ ) seen from the input side,

_{Z 1 = V 1 / I 1} = (jZ 0 · I 2) / ((j / Z 0) · V 2) ··· formula (5)

Because here _{V 2 = Z 2 · I 2} ,

Z ₁ = Z ₀ / (Z ₂ / Z ₀ ) = Z ₀ ² / Z ₂ ...

This indicates that when the half wave / 4 = the line length, when the 100 ohm impedance is connected to the output terminal of the 50 ohm intrinsic impedance line, it appears to be 25 ohms when viewed from the input side. (Z ₂ ) is converted to Z ₁ at the transmission front. Thus, impedance conversion is achieved.

Also, in the formula (4)

V ₁ = jZ ₀ · I ₂

_{I1 = (j / Z 0 ·} V 2 ··· ( expression 7)

From the above, it can be seen that the voltage is proportional to the current at the other end and the current is proportional to the voltage at the other end.

Only when the line length L of the transmission line is the first half wavelength / 4, the relationship between the above ① and ② is established and voltage conversion is performed.

In this way, since the boosting ratio is determined by the ratio of the natural impedance of the transmission line and the load resistance (resistance of the load device), the transformer of the first embodiment has an impedance characteristic of a cold cathode tube in which resistance decreases at start-up and resistance at start-up requiring high voltage. This is suitable.

Next, the transformer operation of the first embodiment will be described using the above equations (1), (7) and FIG. 4.

4 is a graph for explaining the step-up action of the transformer transmission line of the first embodiment. In the graph of FIG. 4, the horizontal axis represents the ratio of the impedance Z ₂ seen from the output axis to the intrinsic impedance Z ₀ of the line 10.

It is assumed here that the input voltage V ₁ is a constant voltage.

In the case where the load impedance Z ₂ is equal to the intrinsic impedance Z ₀ of the transmission line 10 (Z ₂ / Z ₀ = 1), the transmission line 10 is in a matched state, and is indicated at point A in the figure. As can be seen, the voltages at the transmitter and receiver are equal.

When a load of Z ₂ > Z ₀ is connected (Z ₂ / Z ₀ > 1), Z ₁ <Z ₀ is obtained according to Equation (6) above, and the input current I ₁ increases. In addition, in the above formula (7), since the receiving terminal voltage V ₂ is proportional to the input voltage I ₁ , the receiving terminal voltage V ₂ increases equally as indicated by point B in the figure.

In the region where Z ₂ > Z ₀ , V ₂ is greater than V ₁ and is boosted. Therefore, when the line length L is connected to a load of the transmission line 10 of the quarter wavelength on the transmission line at the operating frequency and larger than the inherent impedance of the line 10, the line 10 is connected at both ends of the load. A voltage higher than the input voltage is applied at a magnification according to the ratio with the inherent impedance.

Next, in the transformer of the first embodiment, the reason why the wavelength can be shortened and the transformer can be miniaturized by using the core 4 as described above will be described.

The wavelength in free space is shown by following formula (8).

λ = v / f ... (8)

If the permeability and dielectric constant of the portion where the electromagnetic field of the voltage conversion section 2 is generated are large, the propagation velocity v of the traveling wave becomes slow. This propagation velocity (v) is represented by following formula (9).

v [m / s] = 3 × 10 ⁸ × (ε ¹ / 2μ ^1/2 ) ^-1

Therefore, the wavelength in this case is represented by following formula (10).

λ = (v / f) · (ε ^1/2 · μ ^1/2 ) ⁻¹

As can be seen from the above equation (10), the wavelength shortening occurs according to the values of permittivity and permeability, that is, when the permittivity and permeability increase, the wavelength becomes shorter accordingly, and the core 4 is composed of a material having a high permittivity and permeability. The wavelength can be shortened, the core dimension can be shortened, and the transformer can be miniaturized.

As described above, the transformer of the present embodiment can shorten the wavelength due to the effects of both the dielectric properties and the magnetic properties of the cores 4 and 4, thereby shortening the core dimensions. Since the cores 4 and 4 are arranged at the portion where the magnetic field is generated by (10), the effect of shortening the wavelength due to high permeability can be obtained. Because of this, the core size can be shortened, so that the installation area can be small, and the transformer can be miniaturized while maintaining the high boost ratio and high conversion efficiency.

In the present embodiment, the ground conductors 42 and 42 are formed between the cores 4 and 4 and the line conductors 41, and the cores 4 and 4 are formed at portions where the high frequency electric field by the transmission line 10 does not occur. 4) is formed, and even if a high frequency voltage is applied to the transmission line 10, the loss due to the voltage applied to the cores 4 and 4 can be prevented without the voltage being applied to the cores 4 and 4, and the voltage is increased. The ratio can be made high enough and the conversion efficiency can be made higher.

In the present embodiment, since the core is not interposed between the track conductor 41 and the ground conductors 42 and 42, the dielectric constant of the core affects the capacitance between the track conductor 41 and the ground conductors 42 and 42. The dielectric constant of the core does not affect the capacitance between the wire conductors 41 and the wires. This prevents the capacitance between the line conductors 41 from mutually increasing relative to the capacitance between the line conductors 41 and the ground conductors 42 and 42 even when the line conductors 41 are densely arranged and downsized. As a result, it can function as a distributed constant circuit.

Further, in the transformer of the present embodiment, it is possible to achieve both high boost ratio and high conversion efficiency without using an auxiliary transformer such as a winding transformer, so that the thickness can be reduced compared to the piezoelectric transformer using the auxiliary transformer.

In addition, by simply forming the cores 4 and 4 on the outside of the transmission line 10 composed of the line conductor 41 and the ground conductors 42 and 42, the high boost ratio and the high conversion efficiency can be achieved. Simplification of is possible.

In addition, since the line conductor 41 can be formed on the insulating layer 45 by a method such as plating or sputtering, a conductor having a small thickness can be formed, thereby providing a thin transformer.

Therefore, according to the transformer of the first embodiment, even if the line conductor 41 is densely arranged, it functions as a distributed constant circuit, which makes it possible to further reduce the size and thickness, and to prevent the loss caused by the voltage applied to the core, thereby increasing the boost ratio. The transformer can be made higher, conversion efficiency can be made higher, and the structure can be simplified.

In the transformer of the present embodiment, one or two or more elements T selected from the group of Fc, Co, and Ni, and Hf, Zr, W, Ti, V, and Nb as materials forming a pair of cores 4 and 4 , Mo, Cr, Mg, Mn, Al, Si, Ca, Sr, Ba, Cu, Ga, Ge, As, Se, Zn, Cd, In, Sn, Sb, Te, Pb, Bi, Rare Earth Elements It is a pair of cores using what consists of a synthetic resin and the soft magnetic alloy powder containing 1 type (s) or 2 or more types of elements M selected, 1 type (s) or 2 or more types of elements D selected from the group of O, C, N, and B. The permeability and dielectric constant of (4,4) can be increased, and the wavelength shortening effect is sufficient, so that the transformer can be miniaturized.

As said soft magnetic alloy powder, what is represented by the following composition formulas is used preferably, for example.

T _a M _b D _c

(In the above formula, T represents one or two or more elements selected from the group of Fe, Co, Ni, and M represents Hf, Zr, W, Ti, V, Nb, Mo, Cr, Mg, Mn, Al, Si, Ca, Sr, Ba, Cu, Ga, Ge, As, Se, Zn, Cd, In, Sn, Sb, Te, Pb, Bi, represents one or two or more elements selected from the group of rare earth elements, D represents 1 type, or 2 or more types of elements selected from the group of O, C, N, and B. In addition, a, b, and c which represent a composition ratio in a composition formula are 40 <= a <87, 0 <b <= in atomic% 20, 0 <c ≤ 50 is satisfied.)

As the synthetic resin, a material having a low dielectric loss (that is, a material having a large Q and having a Q of 400 or more) is used. For example, polypropylene, polyethylene, polystyrene, paraffin, polytetrafluoroethylene, polycarbonate, silicone resin, or the like is used. Can be mentioned.

Each core 4 made of the soft magnetic alloy powder and the synthetic resin as described above can be produced, for example, by the following method.

First, each raw material is measured so that a composition formula may be a composition of the soft magnetic alloy powder represented by T _a M _b D _c . As a raw material here, the powder of T and the powder of M are used. As the powder of T, a powder selected from the group consisting of one or more elements selected from the group of Fe, Co, and Ni, oxides, carbides, carbonates, nitrides and borides is used. Powders of M include Hf, Zr, W, Ti, V, Nb, Mo, Cr, Mg, Mn, Al, Si, Ca, Sr, Ba, Cu, Ga, Ge, As, Se, Zn, Cd, In A powder selected from the group consisting of one or more elements selected from the group of, Sn, Sb, Te, Pb, Bi, and rare earth elements, oxides, carbides, carbonates, nitrides and borides is used. Examples of the rare earth elements include Lanthanoids such as Sc, Y, or La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Td, Dy, Ho, Er, Tm, Yb, Lu, etc. belonging to Group 3A of the periodic table. One or more types of elements or mixtures thereof selected from the group can be mentioned.

At this time, it is preferable that the powder of T is 100 micrometers or less, and the powder of M is 2 micrometers or less.

Subsequently, in the case of adding O, C, or N out of D, the above-described powder of T and M powder are sealed together with a stainless ball of the same material as the pot in a pot made of stainless steel, and the group of O, C, N The gas of D selected from a single gas, an oxide gas, and a carbide gas of at least one element selected from the above is filled. In addition, a soft magnetic alloy powder in which the composition formula is represented by T _a M _b D _c can be obtained by mechanical alloying which is pulverized and stirred for a predetermined time using a high energy type planetary ball mill.

The mechanical pulling time is preferably 2 hours or more in terms of being able to sufficiently refine the crystal of the bcc structure or the fcc structure, or the T in which they are mixed.

The soft magnetic alloy powder obtained here has an average particle diameter of about 1 to 2 µm having a structure in which the microcrystalline phase of T having a bcc structure in the order of several nm to several 10 nm is surrounded by an amorphous phase containing a large amount of M and D. Phosphorus aggregated particles. This soft magnetic alloy powder exhibits excellent soft magnetic properties because the average particle diameter of the bcc structure or fcc structure constituting the aggregated particles or the microcrystals of T in which they are mixed is fine, and the bcc structure or fcc structure or T in which these are mixed Since the microcrystals are surrounded by a high resistance amorphous phase, the eddy current loss can be suppressed to be small.

Next, the obtained soft magnetic alloy powder is dispersed in a synthetic resin liquid containing an organic solvent as a solvent to obtain a slurry, and the slurry is repeatedly passed through three rolls, and kneaded until the slurry becomes powder. Get Xylene, toluene, benzene, etc. are mentioned as an organic solvent which melt | dissolves this synthetic resin.

Although the ratio which adds a soft magnetic alloy powder to synthetic resin can be suitably changed with the magnetism and dielectric property of the target core, it is preferable to add so that it may become about 50-80 vol% by the volume ratio in a slurry.

If the volume ratio of the soft magnetic alloy powder is less than 50 vol%, the permeability may be lowered. On the other hand, if it is more than 80 vol%, there may be a problem that it is difficult to mold by injection molding or the like.

The soft magnetic alloy powder is preferably heat-treated in an atmosphere selected from air, oxygen, nitrogen, water vapor, or a mixed atmosphere thereof before dispersing and kneading the synthetic resin liquid. As for the heating temperature here, about 25 degreeC-about 300 degreeC, and as for heating time, 0.5 hour-about 48 hours are preferable. In this case, since an insulating layer made of an oxide is formed on the surface of the soft magnetic alloy powder, the resistivity of the soft magnetic alloy powder is increased, and the dielectric constant at high frequency can be lowered. In addition, the insulating layer here may be formed using not only an oxide film but another insulating film.

Subsequently, the kneaded product is put into a dryer or the like, heated to evaporate the organic solvent, and then molded into a desired shape using a press molding machine, an injection molding machine, an extrusion apparatus, or the like to produce a molded body. Subsequently, the core 4 having the target magnetic properties and dielectric properties can be obtained by heating the molded product at about 150 to 400 ° C. for about 1 hour.

The core 4 made of the soft magnetic alloy powder and the synthetic resin is mixed with the powder of T and the powder of M, and then pulverized and stirred in the gas atmosphere of D, instead of the powder of T, the powder of M, and the powder of D. After the powder is mixed, pulverization and stirring in the inert gas atmosphere or in the gas atmosphere of D selected from the group gas, oxide gas, and carbide gas of at least one element selected from the group of O, C, and N are prepared as described above. It can also manufacture by the method similar to an example.

As the powder of D, one or more or a mixture selected from carbon and B is used.

In this example, the pulverization and stirring of the powder of T, the powder of M and the powder of D are carried out under a gas atmosphere of D, or under an inert gas atmosphere such as Ar gas, or an inert gas such as gas of D and Ar gas. In the mixed gas atmosphere mixed with the above, in the mixed gas atmosphere, the amount of oxygen, carbon and nitrogen in the material can be adjusted.

The core 4 made of the soft magnetic alloy powder and the synthetic resin is the same as the above-described manufacturing example except that the powder of TM alloy thin ribbon obtained by the liquid quenching method is used instead of the powder of T and the powder of M. It can also manufacture by a method.

In addition, the core 4 made of a soft magnetic alloy powder and a synthetic resin is a powder of a TM alloy thin ribbon obtained by the liquid quenching method in addition to the powder of T, the powder of M, the powder of D and / or the gas of D. Except for using it, it can also manufacture by the method similar to the manufacture example mentioned above.

When the core 4 is composed of _a synthetic resin having a low dielectric loss and a soft magnetic alloy powder represented by T _a M _b D _c , the resistivity of the core 4 becomes 10 ⁸ Ω · cm or more, and the synthetic resin Dielectric properties as an insulator (dielectric) that can have, and soft magnetic properties that the soft magnetic alloy powder has.

As described above, the pair of cores 4 and 4 composed of the soft magnetic alloy powder and the synthetic resin represented by the composition formula T _a M _b D _c have a sufficiently high permeability and permittivity, and thus the outer side of the transmission line 10. In the transformer in which a pair of cores 4 and 4 are formed in the groove, the wavelength shortening effect is sufficient and the core dimension can be shortened, and the transformer can be miniaturized.

Next, a second embodiment of the transformer of the present invention will be described. It is a figure which shows schematic structure of the transformer of 2nd Embodiment.

Parts of the transformer of the second embodiment different from the transformer of the first embodiment shown in Figs. 1 and 2 are not formed on both sides of the track conductor 41, but on one side (lower surface in the drawing) of the track conductor 41. The ground conductor 42 is formed through the 45, and the core 4 having dielectric and magnetism is formed on the lower surface of the ground conductor 42.

A first adhesive layer 6a is interposed between the core 4 and the ground conductor 42, and a second adhesive layer 6b is interposed between the ground conductor 42 and the insulating layer 45.

As described above, a cold cathode tube 20 is connected to the output (receive end) terminal (not shown) of the line conductor 41, and is connected to an AC power supply (not shown) to the input side (transmission end side) terminal (not shown). The switch circuit 35 is connected.

The cold cathode tube 20 is connected to the output terminal (not shown) of the ground conductor 42, and the switch circuit 35 connected to the AC power source is connected to the input terminal.

According to the transformer of the second embodiment, the configuration as described above can exhibit substantially the same effect as the transformer of the first embodiment, and the insulating layer 45 is not provided on both sides of the line conductor 41 but on one side thereof. ), The ground conductor 42 is formed, and since the core 4 having dielectric and magnetism is formed on the lower surface of the ground conductor 42, the structure can be simplified more than that manufactured in the first embodiment. have.

Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited only to these Examples.

Experimental Example 1

A transformer (Example 1) similar to the transformer of the first embodiment shown in FIGS. 1 to 2 was produced.

The thickness of each core 4 made of Mn-Zn ferrite in the voltage converting section 2 of the transformer thus manufactured is 0.5 mm, the real part (μ ') of permeability is 1500, and the imaginary part (μ ") of permeability is 20. The dielectric constant (ε _F ) is set to 1.O × 10 ⁵ and the specific resistance (ρ) is set to 3.0 Ω m The line length L of the spiral coil transmission line 10 formed inside the cores 4 and 4. Is almost equivalent to a quarter wavelength on the transmission line at the operating frequency, the thickness of the line conductor 41 is 35 µm, the width is 0.23 mm, the number of turns is 19.5, the conductor spacing is 0.30 mm, and each of the ground conductors 42 The thickness is set to 38 μm, and among the insulating layers 45 and 45 made of polyimide (ε = 4), the thickness of the lower insulating layer 45 of the line conductor 41 is 70 μm and the upper side of the line conductor 41. The thickness of the insulating layer 45 was set to 7 micrometers, and the total thickness of the 1st-3rd contact bonding layers 6a-6c was set to 236 micrometers.

6 and the outer transformer (Comparative Example 1) were produced for comparison.

The thickness of each core 84 made of Mn-Zn ferrite in the voltage converter 102 of the transformer thus manufactured is 0.5 mm, the real part (μ ') of permeability is 1500, and the imaginary part (μ ") of permeability is 20. The dielectric constant (ε _F ) is set to 1.0 × 10 ⁵ , the specific resistance (ρ) is set to 3.0 Ωm, and the line length L of the spiral coil transmission line 100 is equal to 1/4 wavelength on the transmission line at the operating frequency. Almost equivalent, the thickness of the inner conductor 91 was 35 µm, the width was 0.23 mm, the number of turns was 19.5, the conductor spacing 0.30 mm, and the thickness of each outer conductor 92 was set to 38 µm, and the polyimide (ε = 4) The thickness of the insulator 85 below the inner conductor 91 among the insulating layers 85 and 85 composed of 4) is set to 70 µm, and the thickness of the insulator 85 above the inner conductor 91 is set to 7 µm. (86) The sum total thickness of 5 layers was set to 236 micrometers.

The transformer load characteristics of the transformer of Example 1 and the transformer voltage converter of Comparative Example 1 were measured.

The measurement here was carried out using an impedance analyzer HP4194A (trade name: manufactured by Nippon Hewlett-Packard Co., Ltd.) with the termination resistances connecting the measurement of the gain (Gv) to the output terminal at 100 kΩ, 47 kΩ, and 10 kΩ. The measurement frequency range was 0.01-1 MHz. The carbon film resistor was used for the terminal resistance (RL). The measurement results are shown in Table 1 together.

In Table 1, Gv represents a gain.

From the results shown in Table 1, the transformer of Example 1 having a ground conductor formed between the core and the line conductor (with the core formed outside of the transmission line) has a transformer of Comparative Example 1 having a core interposed between the inner conductor and the outer conductor. It is understood that the gain (step-up ratio) is higher than that of the circuit, and that the higher the terminal resistance, the higher the gain (step-up ratio) can be obtained.

As described above, the transformer of the present invention includes a voltage converting unit comprising a line conductor and a ground conductor constituting a transmission line, and a core having dielectric and magnetism, wherein the line length L of the transmission line is at the operating frequency. The ground conductor is set substantially equal to a quarter wavelength on the transmission line, and the ground conductor is formed between the core and the line conductor to form a core having dielectric properties and magnetism in a portion where no high frequency electric field is generated by the transmission line. Even when a high frequency voltage is applied to the transmission line, voltage is not applied to the core, thereby preventing a loss due to voltage on the core, and a boosting ratio can be sufficiently high, resulting in higher conversion efficiency.

Further, in the converter of the present invention, no core is interposed between the line conductor and the ground conductor, so the dielectric constant of the core does not affect the capacitance between the line conductor and the ground conductor, and between the line conductors and each other. The capacitance does not affect the dielectric constant of the core. This makes it possible to function as a distributed constant circuit because it is possible to prevent the capacitance between the line conductors from increasing relative to the capacitance between the line conductor and the ground conductor even when the line conductor is densely arranged and downsized. .

Therefore, according to the present invention, even if the line conductor is densely arranged, it functions as a distributed constant circuit and can be further miniaturized and thinned, and can further increase the boost ratio by preventing loss due to voltage applied to the core, and improve conversion efficiency. It is possible to provide a transformer which can be made higher and further simplify the structure.

Claims (6)

A voltage conversion section comprising a line conductor and a ground conductor constituting the transmission line, and a core having dielectric and magnetic properties, wherein the line length L of the transmission line is approximately equal to 1/4 wavelength on the transmission line at the operating frequency. And the grounding conductor is formed between the core and the line conductor. The method of claim 1, And the line conductor is formed in a plane shape, and the ground conductor is laminated on at least one surface of the line conductor through an insulator, and the core is stacked on the ground conductor. The method of claim 1, And a load device having an impedance different from the inherent impedance of the voltage converter. The method of claim 2, And the insulator is made of a material having an effective dielectric constant (ε) of less than ten. The method of claim 1, The core is a transformer, characterized in that consisting of one or two or more selected from Mn-Zn ferrite, Ni-Zn ferrite, Ni-Cu ferrite. The method of claim 1, A transformer having an effective permeability (μ) of 100 to 20000 and an effective dielectric constant (ε) of 10 to 5000 at 100 Hz of the core.