KR20000022812A - Transformer - Google Patents

Abstract

PURPOSE: A transformer is provided to have a high boosting rate, high conversion efficiency and to simplify the structure, even though the transformer got thinner and miniaturized. CONSTITUTION: A transformer comprises: a transmission line(10) composed of one pair of conductor(11,12); a voltage conversion section(2) having a core with dielectric activity and magnetism; and a cold cathode tube having a characteristic impedance and other impedances. The voltage conversion section(2) is composed of a core section(3) and the transmission line(10). The core section(3) forms an insulating layer(6) on both sides of the core(4) through a first adhesion layer(5). A second adhesion layer(7) is formed on the insulating layer(6). Materials of the core(4) are compositions of a first species or a second species, selected in a group of Mn-Zn ferrite, Ni-Zn ferrite, and Ni-Cu ferrite.

Description

Transformers {TRANSFORMER}

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

In general, it is known that a boost transformer is provided in a backlight inverter of a liquid crystal display device. As a boost transformer used for such a use, the winding transformer is conventionally used. This winding transformer is connected to the cold cathode tube through the ballast capacitor. Mercury is enclosed in the cold cathode tube, and electrons generated by applying a high voltage impinge on the mercury to generate ultraviolet rays, and the ultraviolet rays are excited to emit phosphors coated inside the tube to convert them into visible light. have. Such a cold cathode tube needs to be applied with a high voltage because electrons are generated during startup. However, once the discharge is started, the voltage holding the discharge is about one third of the startup voltage. At this time, it is enough to flow a current of about 5 to 6 mA to the cold cathode tube, and no large current is necessary. Therefore, the characteristics desired for the boosting transformer used for such a use are that the output voltage can be raised for a moment at the start of the discharge of the cold cathode tube, and can be reduced to the discharge holding voltage in the normal state.

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

However, in the conventional inverter, there is a problem that the conversion efficiency is lowered when the thinning is realized by using the winding transformer. The reason for this is that if the shape of the core is flattened to make the winding transformer thin, as a result, the winding is lengthened and the DC resistance increases. In addition, in the case of using the winding transformer, the installation area is large, which limits the miniaturization.

Therefore, an inverter for backlight having a piezoelectric transformer made of a flat ceramic element instead of a winding transformer is considered. This piezoelectric transformer can be thinned while maintaining high conversion efficiency. However, since the voltage raising ratio is insufficient, the winding transformer may be used as an auxiliary transformer, thereby limiting the thinning. In addition, since the boost ratio and the resonance frequency of the piezoelectric transformer are determined by the shape of the element and the electromechanical coupling coefficient, when the size of the element is reduced, the resonance frequency is shifted to the high frequency side and the boost ratio is also reduced. The size of the unit cannot be made too small, and as in the winding transformer, the installation area becomes large, which limits the miniaturization of the inverter. Moreover, in a piezoelectric transformer, in order to make high voltage raising ratio and high conversion efficiency compatible, it is necessary to set it as a laminated structure or to make rectangular shape of 20-30 mm long side, and a structure becomes comparatively complicated.

On the other hand, as a transformer applying the impedance conversion action, there have been reported examples of using a high frequency coaxial cable as a distribution constant line for a lighting device such as a discharge lamp and using this high frequency coaxial cable as a voltage converter. As the 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 insulator of the coaxial cable is low, and for example, in order to use at 1 MHz, the length of the coaxial cable needs to be about 49 m. In particular, the backlight inverter of the liquid crystal display device In the case of use as a wire, it is necessary to make the length of the coaxial cable about 884 m in order to use it at about 60 Hz, and it was difficult to downsize.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transformer in which the pressure-up ratio is high, the high conversion efficiency, and the structure can be simplified even though the thickness and size are reduced.

1 is a perspective view illustrating a schematic configuration of a transformer of a first embodiment of the present invention;

2 is a cross-sectional view showing the transformer of FIG.

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

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

5 is a sectional view showing a schematic configuration of a transformer of a second embodiment of the present invention;

6 is a sectional view showing a schematic configuration of a transformer of a third embodiment of the present invention;

FIG. 7 is a plan view illustrating a voltage transformer of the transformer of FIG. 6; FIG.

8 is a sectional view showing a schematic configuration of a transformer of a fourth embodiment of the present invention;

9 is a sectional view showing a schematic configuration of a transformer of a fifth embodiment of the present invention;

Fig. 10 shows gain-phase characteristics when the terminal resistance is 1 kHz;

Fig. 11 shows gain-phase characteristics when the terminal resistance is 10 k ?;

Fig. 12 shows the personal-phase characteristics when the terminating resistor is 20 k ?;

Explanation of symbols on the main parts of the drawings

2: voltage conversion unit 4: core

10 transmission line 11: conductor

12: conductor 20: cold cathode tube (loading device)

31: conductor 32: conductor

41: inner conductor 42: outer conductor

The transformer according to the present invention is characterized by comprising at least a voltage converter comprising a transmission line composed of at least one pair of conductors and a core having dielectric and magnetic properties.

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

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 the group of Mn-Zn ferrite, Ni-Zn ferrite, Ni-Cu ferrite.

Moreover, in the modification group which concerns on this invention, the said core is 1 type (s) or 2 or more types of elements T chosen from the group of Fe, Co, Ni, Hf, Zr, W, Ti, V, Nb, Mo, Cr, 1 or 2 selected from the group of 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 preferable that a soft magnetic alloy powder containing at least one element M, at least one element D selected from the group of O, C, N, and B, and a synthetic resin is used.

Moreover, in the modification machine which concerns on this invention, it is preferable that the effective permeability (micro) at 100 Hz of the said core is 10-200000, and the effective dielectric constant (epsilon) is 10-5000.

In the transformer according to the present invention, it is preferable that the line length L of the transmission line is approximately equal to 1/4 wavelength of the voltage frequency applied to the transmission line.

In the transformer according to the present invention, the pair of conductors of the transmission line may be an inner conductor provided between the cores and an outer conductor provided outside the cores.

Embodiment of the Invention

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of the transformer of this invention is described. In addition, in embodiment described below, the case where the transformer of this invention is applied to the backlight inverter of a liquid crystal display device is described.

1 is a perspective view showing a schematic configuration of a transformer of a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the transformer of the first embodiment.

The transformer of the first embodiment is constituted by a voltage converter 2 and a cold cathode tube 20 serving as a load device.

The voltage conversion section 2 is composed of a core section 3 and a transmission line 10.

As shown in FIG. 2, the core portion 3 is provided with an insulating layer 6 formed on both surfaces of the core 4 having dielectric properties and magnetism through the first adhesive layer 5, and the insulating layer 6. The second adhesive layer 7 is formed on the substrate.

As the material for forming the 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 4. It is preferable at the point which can downsize a transformer.

It is preferable that the effective permeability (micrometer) in the core 4 is 100-20000, and, as for the core 4, it is preferable that the effective dielectric constant (epsilon) is 10-5000.

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 that an optimal range exists in 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, it is preferable that µ and ε are in the above ranges.

As the material forming the insulating layer 6, polyimide or the like is used.

The transmission line 10 consists of a pair of conductors 11 and 12. As shown in FIG. These pairs of conductors 11 and 12 are formed to be wound around the core portion 3, respectively. Moreover, in this transmission line 10, the direction of the electric current which flows in the conductor in one surface side of the core part 3, and the conductor in the other surface side is reversed (the current direction reverses in the front and back of the core part). Thus, the magnetic flux is made stronger. In this 1st Embodiment, the one conductor 11 and the other conductor 12 are formed so that the magnetic flux may face the direction of the arrow MF in the core part 3. In the figure, the direction of the arrow shown by the symbols I _a and I _b is the direction of the magnetic flux generated by the current flowing through the conductors 11 and 12.

As a method of forming such a transmission line 10 around the core part 3, for example, the adhesive layer 5 which forms a conductor by plating or sputter | spatter on the insulating layer 6 which winds up general covering copper wire. ), The insulating layer 6, the second adhesive layer 7, and the conductor are integrally formed into strips, and formed on a predetermined surface on both surfaces of the core 4.

The cold cathode tube 20 is connected to the terminal 11a of the output side (means side) of one of the conductors 11 of such a transmission line 10, and is connected to the terminal 11b of the input side (transmission side). A switch circuit (not shown) connected to the power supply (not shown) is connected. Moreover, the said cold cathode tube 20 is connected to the terminal 12a of the output side (means side) of the other conductor 12, and the said AC power supply (not shown) to the terminal 12b of the input side (transmission side). ) Is connected to a switch circuit (not shown).

It is preferable that the line length L of each conductor 11, 12 of the transmission line 10 is approximately equal to the 1/4 wavelength of the frequency (operating frequency) of the AC voltage applied to this transmission line 10. If the line length L of the transmission line 10 is not nearly equal to a quarter wavelength of the frequency (operating frequency) of the AC voltage applied to this transmission line 10, it is larger than the intrinsic impedance of the voltage conversion section 2. When the cold cathode tube 20 having an impedance is connected, impedance conversion and voltage conversion are not performed, which is not preferable.

As the cold cathode tube 20, the one having an impedance different from the intrinsic impedance of the voltage conversion section 2 having the above-described configuration is used depending on the ratio between the inherent impedance of the voltage conversion section 2 at both ends of the load. It is preferable to apply a voltage different from the input voltage at a magnification. In addition, it is preferable that the cold cathode tube 20 uses an impedance having a larger impedance than the intrinsic impedance of the voltage conversion section 2. It is more preferable in that a voltage higher than the input voltage is applied at a magnification according to the ratio with the intrinsic impedance of the unit (2).

In the transformer of this first embodiment, the direction of the magnetic flux is in the direction indicated by the arrow MF in FIG. 1.

In the transformer of the first embodiment having the above-described configuration, the parasitic capacitance (distribution constant) is put in the circuit constant, and as shown in FIG. 3 using the core 4 and the transmission line 10 having dielectric and magnetic properties. Distribution constant circuit is constructed. In Fig. 3, symbol V ₁ denotes an input voltage, V ₂ denotes a means voltage, I ₁ denotes an input current, I ₂ denotes a means current, and Z ₁ denotes an impedance seen from the input side. , (Z ₂ ) is the impedance seen from the output side, (Z ₀ ) is the intrinsic impedance of the transmission line 10, and (L) is the line length of each conductor (11, 12).

The distribution constant circuit shown in FIG. 3 is expressed by the following equation.

Where (V ₁ ) is the input voltage, (V ₂ ) is the instrument voltage, (I ₁ ) is the input current, (I ₂ ) is the instrument current, (Z ₁ ) is the impedance seen from the input side, and (Z ₂ ) is The impedance seen from the output side, (Z ₀ ) is the intrinsic impedance of the transmission line (10), (L) is the line length of each conductor (11, 12), (β) is the propagation constant of the transmission line (10) (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 the present embodiment, since the line lengths L of the conductors 11 and 12 are respectively lambda / 4 of the operating frequency, the following equation (2) is obtained.

Therefore, Equation 1 can be represented by Equation 3.

The above equation (3) is modified to obtain the impedance (Z ₁ ) seen from the input side, and the following equation (4) is obtained.

Since V ₂ = Z ₂ · I ₂ , the following equation (5) is obtained.

This indicates that in the case of the total wavelength / 4 = transmission line length, when 100 ohm impedance is connected to the output terminal of the transmission line with intrinsic impedance 50 ohms, 25 ohms is seen from the input side. Impedance (Z ₂ ) connected to (受 電 端) is converted into Z ₁ from the power transmission terminal. Thus, the impedance is converted.

In addition, the following equation (6) is obtained from the above equation (3).

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 a full 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 10 and the load resistance (resistance of the load device), the transformer of the first embodiment has high resistance at start-up and high resistance at start-up that require high voltage. It is suitable for the impedance characteristics of cold cathode tubes.

Next, operation | movement of the transformer of 1st Embodiment is demonstrated using said Formula (5), 6, and FIG.

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

Here, it is assumed that the input voltage V ₁ is a constant voltage.

When 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 is in a matched state, as shown at point A in the figure. Likewise, it is clear that the voltages of the transmitter and the means are the same.

When a load of Z ₂ > Z ₀ is connected (Z ₂ / Z ₀ > 1), Z ₁ <Z ₀ is obtained from the above equation (5), and the input current I ₁ increases. Further, from the above equation (6), since the means voltage (V ₂ ) is proportional to the input current (I ₁ ), as shown in point B in the figure, it increases equally.

In the region of Z ₂ > Z ₀ , V ₂ is larger than V ₁ and is elevated. Therefore, when the line length L is a load of the transmission line 10 having a quarter wavelength of the operating frequency, and a load larger than the intrinsic impedance of the line 10 is connected, the transmission 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 intrinsic impedance of.

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

The wavelength in free space is represented by the following equation.

λ = v / f

If the permittivity and permeability of the portion where the electric 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 the following formula (8).

Therefore, the wavelength in this case is represented by the following equation (9).

As is clear from Equation 9, wavelength shortening occurs according to the values of permittivity and permeability, that is, when the permittivity and permeability increase, the wavelength is shortened accordingly, and thus, the core 4 is composed of a material having a high permittivity and permeability. By doing so, the wavelength can be shortened, the core dimension can be shortened, and the transformer can be miniaturized.

Therefore, in the transformer of the first embodiment, the voltage converter 2 includes the transmission line 10 composed of a pair of conductors 11 and 12, the core 4 having a dielectric constant and magnetism, and a voltage. By providing a cold cathode tube (loading device) 20 having an impedance different from the intrinsic impedance of the conversion section 2, the wavelength can be shortened, and accordingly the core dimension can be shortened. The ratio and the high conversion efficiency can be maintained and the transformer can be miniaturized.

In addition, even if an auxiliary transformer such as a winding transformer is used, both a high voltage raising ratio and a high conversion efficiency can be achieved, so that the thickness can be thinner than that of a piezoelectric transformer using an auxiliary transformer.

Moreover, only by providing the transmission line 10 in the core 4 having dielectric and magnetic properties, it is possible to make both the high boost ratio and the high conversion efficiency compatible, and the structure can be simplified.

In the transformer of the present embodiment, as the material forming the core 4, one or two or more elements T selected from the group of Fe, Co, and Ni, Hf, Zr, W, Ti, V, Nb, Mo, 1 type selected from the group of Cr, Mg, Mn, Al, Si, Ca, Sr, Ba, Cu, Ga, Ge, As, Se, Zn, Cd, In, Sn, Sb, Te, Pb, Bi, Rare Earth Elements Or a soft magnetic alloy powder comprising two or more elements M, one or two or more elements D selected from the group of O, C, N, and B, and a synthetic resin, the permeability of the core 4 And the dielectric constant can be increased, the wavelength shortening effect is sufficient, and the transformer can be downsized.

As the soft magnetic alloy powder, for example, one represented by the following compositional formula is suitably used.

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 the composition formula, a, b, and c, which represent the composition ratio, are atomic% in terms of 40 ≦ a ≦ 87, 0 < b ≤ 20, 0 <c ≤ 50 to satisfy the relationship).

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. Can be mentioned.

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

First, the quantity of each raw material is measured so that a composition formula may become 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 at least one element selected from the group of Fe, Co and Ni, oxides, carbides, carbonates, nitrides and borides is used. Examples of the powder 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 at least one element 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 element include lanthanides such as Sc, Y, or La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Td, Dy, Ho, Er, Tm, Yb, and Lu, which belong to group 3A of the periodic table. At least 1 type of element chosen from the group, or a mixture thereof is 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 in D, the above-described powder of T and M powder are enclosed in a stainless steel port together with a stainless sphere of the same material as that of the pot. A gas of D selected from a single gas, an oxide gas, and a carbide gas of at least one element selected from the group is filled. Then, a soft magnetic alloy powder in which the compositional formula is represented by T _a M _b D _C is obtained by a mechanical alloy that is pulverized and stirred for a predetermined time using a high energy type planetary ball mill.

It is preferable that the time of the mechanical alloy is 2 hours or more in that the bcc structure, the fcc structure, or the T crystals in which these are mixed can be sufficiently refined.

The soft magnetic alloy powder obtained here has an average particle diameter of 1 having a structure such that the fine crystal phase of T having a bcc structure having an average grain size of several nm to several 10 nm is surrounded by an amorphous phase containing a large amount of M and D. It becomes aggregated particle about -2 micrometers. This soft magnetic alloy powder exhibits excellent soft magnetic properties because of the fine bcc structure or fcc structure constituting the aggregated particles, or the average grain diameter of the fine crystals of T in which they are mixed, and the bcc structure or fcc structure, Or since the microcrystal of T mixed these is surrounded by the high-resistance amorphous phase, the overcurrent loss can be suppressed small.

Next, the excellent soft magnetic alloy powder is dispersed in a synthetic resin solution 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 As an organic solvent which melt | dissolves this synthetic resin, xylene, toluene, benzene, etc. are mentioned.

Although the addition ratio of the soft magnetic alloy powder to the synthetic resin can be appropriately changed depending on the magnetic properties and dielectric properties of the core 4 of interest, it is preferable to add so that the volume ratio in the slurry is about 50 to 80 vol%. If the volume ratio of the soft magnetic alloy powder is less than 50 vol%, there may be a problem of low permeability, and if it exceeds 80 vol%, there may be a problem of difficulty in molding by injection molding or the like.

The soft magnetic alloy powder is preferably heat-treated in an atmosphere selected from air, oxygen, nitrogen, steam, or a mixed atmosphere thereof before dispersing and kneading the synthetic resin liquid. As for the heating temperature here, about 25 degreeC-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 is not limited to an oxide film, You may form using another insulating film.

Subsequently, the kneaded product is put into a drier or the like and heated to evaporate the organic solvent, and then molded into a desired shape by using a press molding machine, an injection molding machine, an extrusion apparatus, or the like to produce a molded article. Thereafter, the core 4 having the target magnetic properties and dielectric properties is 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 After mixing the powders of the powder, and then pulverized and stirred in an inert gas atmosphere or in a gas atmosphere of D selected from the group gas, oxide gas, carbide gas of at least one element selected from the group of O, C, N It can also manufacture by the method similar to the manufacturing example mentioned above.

As said D powder, at least 1 sort (s) or mixture chosen 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 D and gas of Ar. When carried out in a mixed gas atmosphere with gas and under the mixed gas atmosphere, the amount of oxygen, carbon, and nitrogen in the material can be adjusted.

The core 4 composed of the soft magnetic alloy powder and the synthetic resin was manufactured as described above except that the powder of TM alloy ribbon obtained by the liquid quenching method was used instead of the powder of T and the powder of M. It can also manufacture by the same method as an example.

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

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 , whereby the resistivity of the core 4 is 10 ⁸ Pa · cm or more, and the synthetic resin The dielectric property as an insulator (dielectric) which has it, and the soft magnetic property which a soft magnetic alloy powder has can be provided.

The core 4 composed of a soft magnetic alloy powder and a synthetic resin represented by T _a M _b D _C as described above has a sufficiently high permeability and permittivity, and thus, the core 4 and the transmission line 10 are thus large. In the transformer provided with the voltage conversion part 2 which consists of these, especially, a wavelength shortening effect is enough, a core dimension can be shortened and a transformer can be miniaturized.

The modification group of this invention may be a structure as shown in FIG.

5 is a cross-sectional view illustrating the transformer of the second embodiment. The transformer of this second embodiment is different from the transformer of the first embodiment shown in Figs. 1 to 2 in that the cover 22 covering the transmission line 10 is formed at the outermost part.

The cover 22 is provided to prevent electric shock and is made of an insulating material.

The modification group of the present invention may have a structure as shown in Figs.

6-7 is a figure which shows 3rd Embodiment of the transformer of this invention. The transformer of this second embodiment includes a transmission line (10) consisting of a coil conductor (31) and a film conductor (32), a voltage converter (2) including a core (4) having dielectric and magnetic properties; And a cold cathode tube (loading device) 20 having an impedance different from the intrinsic impedance of the voltage converter 2.

The cold cathode tube 20 is connected to the terminal 31a of the output side (means side) of the coil-shaped conductor 31, and is connected to an AC power supply (not shown) to the terminal 31b of the input side (transmission side). The switch circuit 35 is connected.

The cold cathode tube 20 is connected to a terminal on the output side (means side) of the film conductor 32, and a switch circuit connected to the AC power supply (not shown) to a terminal on the input side (transmission side). 35 is connected.

In the transformer of the third embodiment, the boost ratio (gain) and the operating frequency can be adjusted by using the capacitance between the coil conductor 31 and the membrane conductor 32.

According to the transformer of the third embodiment, the configuration as described above enables high voltage-up ratio, high conversion efficiency, and simplified structure even when the thickness is reduced or downsized.

In the transformer of the third embodiment, the case where the conductor 32 is a film form formed on the entire surface of one surface of the core 4 has been described, but a coil may be used.

Moreover, the modification machine of this invention may be a structure as shown in FIG.

8 is a diagram showing a fourth embodiment of the transformer of the present invention. The transformer of the fourth embodiment has a pair of cores 4 and 4 having dielectric and magnetic properties, and a coil-shaped inner conductor 41 and cores 4 and 4 provided between the cores 4 and 4. A voltage conversion section (2) having a transmission line (10) consisting of external conductors (42,42) provided on the outer side of the circuit), and a cold cathode tube (load device) having an impedance different from the intrinsic impedance of the voltage conversion section (2); 20).

The outer conductors 42 and 42 may be coiled or film-like. These external conductors 42 and 42 are electrically connected by the connecting conductor 43 in order to make the potential equal.

According to the transformer of the fourth embodiment, in particular, since two cores 4 are used, the impedance can be increased compared to the transformer of the third embodiment, and the capacitance C can be increased. As a result, the degree of freedom in circuit design is increased.

In addition, the transformer of the present invention may have a structure as shown in FIG. 9.

FIG. 9: is a figure which shows 5th Embodiment of the transformer of this invention. It is a pair of cores 4 and 4 that the transformer of this 5th Embodiment differs from the transformer of 4th Embodiment shown in FIG. It is a point provided only in the outer side of one core 4 of them.

(Example)

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

Example 1

The modification machine similar to the transformer of 2nd Embodiment shown in FIG. 5 was produced. The thickness d of the core part 3 of the voltage conversion part 2 of the transformer manufactured here is 0.955 mm, and the thickness of the sum total of the 1st contact bonding layer 5, the insulating layer 6, and the 2nd contact bonding layer 7 was carried out. (t ₁ ) is 0.325 mm, the thickness (t ₂ ) of the core 4 made of Mn-Zn ferrite is 0.89 mm, the film thickness (t ₃ ) of the conductors 11, 12 is 0.03 mm, and the conductors 11, 12 ), The width W was 1.24 mm. Moreover, the track length L of the conductors 11 and 12 was 0.34 m, respectively. In addition, the cover 22 is provided in the voltage conversion part 2 produced here similarly to 2nd Embodiment of FIG.

The gain phase of the voltage converter of the transformer thus manufactured was measured. For the measurement herein, the impedance analyzer (HP4194A): a terminal resistor (Z _L) for connecting the measurement of the (trade name in Japan Hewlett-Packard Company Manufacturing Co., Ltd.) by the gain-phase (test fixture using the only) use of the terminal on the output side 1 ㏀, The conversion was performed at 10 Hz and 20 Hz. The measurement frequency range was set from 1 MHz to 40 MHz so that the point near the resonance could be taken in detail. As the terminal resistance Z ₁ , a carbon film resistor was used. The measurement results are shown in FIGS. 10 to 12. Also, it represents the value of the frequency (f), the gain (G _V) when tuned to the λ / 4 in the following.

Z _L = 1 kΩ f = 13. 85 (MHz), G _v = 18.22 dB

Z _L = 10 kΩ f = 13.59 (MHz), G _v = 30.22 dB

Z _L = 20 kΩ f = 13. 22 (MHz), G _v = 45. 29 dB

It is understood from the results shown in Figs. 10 to 12 that the gain becomes maximum when the phase (phase difference of the input / output voltage) is -90 (degrees), and the higher gain (step-up ratio) is obtained as the termination resistance increases. .

In addition, when the transformer of the Example was used as a backlight inverter of a liquid crystal display device, the required line length was calculated by the following method, and the use frequency was 60 Hz to 12 cm. The transformer of this example had an effective permeability µ = 1500 and an effective dielectric constant ε = 70000.

As described above, the transformer of the embodiment has a wavelength shortening effect due to the use of a core having magnetic and dielectric properties, and thus, it can be seen that the length of the line can be shortened as compared with the transformer of the comparative example using the coaxial cable described later.

(Comparative Example)

The line length of the conventional transformer (comparative transformer) in which the high frequency coaxial cable was provided as a voltage converter was 884 m. The line length of the transformer of the comparative example calculates and sets the required length when the frequency of use when the transformer is used as a backlight inverter of the liquid crystal display device is 60 Hz as follows. The effective dielectric constant of the insulator of the coaxial cable was ε = 2.

As described above, the transformer of the present invention includes at least a voltage conversion section including a transmission line composed of a pair of conductors and a core having dielectric and magnetism, so that the wavelength can be shortened. Since it is possible to shorten the installation area, the installation area is also small, maintaining a high boosting ratio and high conversion efficiency and enabling a compact transformer.

In addition, even if an auxiliary transformer such as a winding transformer is used, both a high voltage raising ratio and a high conversion efficiency can be achieved, so that the thickness can be thinner than that of a piezoelectric transformer using an auxiliary transformer.

In addition, even if the voltage conversion section has a simple configuration in which only a transmission line is provided in the core having the dielectric and magnetic properties, the high voltage-ratio ratio and the high conversion efficiency can be made compatible, and the structure can be simplified.

In addition, in the case where a load device having an impedance different from the intrinsic impedance of the voltage conversion unit is provided, an input voltage and a different voltage can be added at a magnification according to the ratio of the inherent impedance of the voltage conversion unit to both ends of the load. When the load device has an impedance greater than the intrinsic impedance of the voltage converter, voltage higher than the input voltage may be applied to both ends of the load at a magnification according to the ratio of the inductance of the voltage converter. It can be used suitably for an inverter for backlight.

Claims (7)

A transformer comprising at least a voltage conversion section having a transmission line composed of at least one pair of conductors and a core having dielectric and magnetic properties. The transformer of claim 1, wherein a load device having an impedance different from the inherent impedance of the voltage converter is provided. The transformer according to claim 1 or 2, wherein the core is made of one or two or more selected from the group consisting of Mn-Zn ferrite, Ni-Zn ferrite, and Ni-Cu ferrite. The core according to claim 1 or 2, wherein the core is one or two or more elements T selected from the group of Fe, Co, and Ni, Hf, Zr, W, Ti, V, Nb, Mo, Cr, Mg, One or two or more selected from the group of Mn, Al, Si, Ca, Sr, Ba, Cu, Ga, Ge, As, Se, Zn, Cd, In, Sn, Sb, Te, Pb, Bi, and rare earth elements A transformer comprising: a soft magnetic alloy powder containing an element M, one or two or more elements D selected from the group of O, C, N, and B, and a synthetic resin. The transformer according to claim 1 or 2, wherein an effective permeability (μ) at 100 Hz of the core is 10 to 20,000, and an effective dielectric constant (ε) is 10 to 5000. The transformer according to claim 1 or 2, wherein the line length L of said transmission line is approximately equal to a quarter wavelength of a voltage frequency applied to said transmission line. The transformer according to claim 1 or 2, wherein the pair of conductors of the transmission line is an inner conductor provided between the cores and an outer conductor provided outside the cores.