JP5255290B2 - Piezoelectric transformer - Google Patents

Description

  The present invention relates to a piezoelectric transformer that obtains a desired output voltage using mechanical vibration of a piezoelectric body.

  This type of piezoelectric transformer is used for a high voltage power source such as an inverter for a liquid crystal backlight, and generates a high voltage output with a low voltage input. Specifically, the piezoelectric transformer houses a piezoelectric body (piezoelectric vibrator) in its case, and this piezoelectric body has a function of converting electrical energy into mechanical energy. When an input voltage is applied to the piezoelectric body, the piezoelectric body mechanically vibrates (resonance phenomenon), so that a desired transformed output voltage can be obtained.

  Here, a primary electrode and a secondary electrode are formed on the outer surface of the piezoelectric body, the primary electrode is connected to the input side terminal, and the secondary electrode is connected to the output side terminal. A configuration using a gold thread wire or the like for connection (for example, see Patent Documents 1 and 2) is known.

JP-A-8-32135 JP 2001-185777 A

  By the way, this piezoelectric body is arranged in a state of floating with respect to the case, and the piezoelectric body is fixed to the case using an insulating adhesive. However, in the conventional technology described above, the piezoelectric body is fixed to the case at two locations corresponding to the vibration nodes viewed in the longitudinal direction of the piezoelectric body, which increases the number of locations where the adhesive is applied. There is concern that the amount used will also increase.

In this case, it is also conceivable to apply an adhesive only to one of the vibration nodes and fix the piezoelectric body to the case.
However, for example, when an adhesive is applied only to a node that occurs on the side close to the secondary electrode, the vibration of the piezoelectric material propagates toward the primary electrode based on the application position of the adhesive, and the wire breakage of the wire Further, there is a problem that the connection between the primary electrode and the terminal is hindered because the connection portion may be peeled off by soldering.

On the other hand, for example, even when the adhesive is simply applied only to the node generated in the primary electrode, the problem of hindering conduction between the primary electrode and the terminal still occurs. This is because the insulating adhesive easily comes into contact with the gold thread wire or the like.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a piezoelectric transformer that solves the above-described problems and does not hinder the conduction between the primary electrode and the terminal.

  According to a first aspect of the present invention, there is provided a piezoelectric body having an input-side electrode formed on an outer surface, a case for accommodating the piezoelectric body, a terminal disposed to face the electrode, and an electrode in the case And an elastic member having electrical conductivity that contacts both of the terminals and electrically connects them to each other, and is formed in the case, and holds the elastic member near the vibration node of the piezoelectric body. A folder that is press-fitted between an electrode and a terminal, an adhesive member that has an insulating property to fix the piezoelectric body to the case near the vibration node of the piezoelectric body, and the adhesive member and the folder are formed. Buffer area.

Further, in the above configuration, the piezoelectric body is configured in a substantially rectangular parallelepiped shape, while the electrode is formed on at least one of the surfaces that make a pair in the thickness direction of the piezoelectric body, and the folder is a longitudinal direction of the piezoelectric body. The adhesive member has a piezoelectric body on the upper surface side of the case, while the adhesive member has a positioning surface for disposing the elastic member between the upper surface side and the bottom surface side of the case as viewed in the width direction substantially orthogonal to the direction and the thickness direction. It is fixed to the case, and the buffer area is formed between the adhesive member and the positioning surface.

According to the first invention, the piezoelectric transformer includes the piezoelectric body having the input-side electrode formed on the outer surface, and the piezoelectric body is accommodated in the case. The piezoelectric transformer includes a terminal disposed to face the input side electrode, and an elastic member is disposed between the electrode and the terminal. This elastic member has conductivity, and can contact both of the electrodes and the terminals so that they can conduct each other.

Here, the piezoelectric transformer includes a folder. This folder holds the elastic member in the case, that is, holds the elastic member so that the elastic member does not move in the case. The elastic member is securely pressed between the electrode and the terminal. Can be placed. This folder holds the elastic member in the vicinity of the node of the vibration of the piezoelectric body generated at the input side electrode.

On the other hand, the adhesive member also fixes the piezoelectric body to the case in the vicinity of the vibration node of the piezoelectric body, but a buffer region is formed between the adhesive member and the folder. In other words, the position of the adhesive member and the position of the folder where the elastic member is arranged are separated by the buffer area. Therefore, it becomes difficult for the insulating adhesive member to come into contact with the elastic member having conductivity, and this elastic member can reliably exhibit the conduction function between the electrode and the terminal.

In addition, if the adhesive member is fixed to the case near the node of the vibration of the piezoelectric body generated by the electrode on the input side, the vibration of the piezoelectric body can be reliably suppressed, and the elastic member is also worn away. Can be prevented.
As a result, the reliability of the piezoelectric transformer is improved.

Et al of the piezoelectric body, the longitudinal direction is configured in a substantially rectangular parallelepiped shape made of the thickness direction, and the width direction, the electrodes are formed on at least one of the surfaces of the pair in the thickness direction. The folder has a positioning surface, and the elastic member is disposed between the upper surface side and the bottom surface side of the case as viewed in the width direction via the positioning surface. On the other hand, the adhesive member fixes the piezoelectric body to the case on the upper surface side of the case, and a buffer region is formed between the adhesive member and the positioning surface.
That is, a buffer region is formed between the adhesive member and the positioning surface on which the elastic member is arranged, and the positional relationship is more clearly distinguished, so the adhesive member does not advance toward the elastic member, The elastic member is not affected by the adhesive member.

According to a second invention, in the configuration of the first invention, the positioning surface is formed between a bottom surface side of the case and a substantially central position of the electrode when viewed in the width direction of the piezoelectric body.
According to the second invention, in addition to the action of the first invention, when the positioning surface is formed between the bottom surface side and the substantially center position of the electrode when viewed in the width direction, when the piezoelectric transformer is assembled, Compared to the case where the elastic member is inserted up to the deepest part of the case, the elastic member can be easily placed between the electrode and the terminal in a press-fitted state.

According to a third invention, in the configuration of the first or second invention, a rib for holding an adhesive member is provided on the upper surface side of the case.
According to the third invention, in addition to the effects of the first and second inventions, since the adhesive member is held by the rib provided on the upper surface side of the case, the adhesive member faces the elastic member. It becomes harder to progress.

According to a fourth invention, in the configuration of the first to third inventions, an opening is formed on the upper surface side of the case so as to penetrate the case and visually recognize the piezoelectric body from the outside.
According to the fourth invention, in addition to the effects of the first to third inventions, an opening penetrating the case is formed on the upper surface side of the case, and the opening allows the piezoelectric body to be visually recognized from the outside. It is configured. Therefore, the adhesive member can be applied to the inside of the case before or after the piezoelectric body is accommodated in the case, and compared with the case where the adhesive member is applied from the bottom surface side to the upper surface side of the case. Work becomes easier. In addition, since the adhesive member does not easily come into contact with a terminal requiring conduction in addition to the elastic member, the influence of the adhesive member does not appear on this terminal. Further, whether or not the application work of the adhesive member is completed becomes clear from the opening.

According to a fifth aspect of the invention, in the configuration of the fourth aspect of the invention, the opening is formed in such a size that only the vicinity of the piezoelectric body and the electrode is visible from the outside as viewed in the thickness direction of the piezoelectric body.
According to the fifth aspect of the invention, in addition to the action of the fourth aspect of the invention, the size of the opening is such that only the vicinity of the piezoelectric body and the electrode on the input side can be visually recognized from the outside in the thickness direction of the piezoelectric body. If it is formed, the adhesive member is most difficult to proceed toward the elastic member.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive member which has insulation becomes difficult to contact the elastic member which has electroconductivity, and the adhesive member can provide the piezoelectric transformer which does not inhibit conduction | electrical_connection with the electrode and terminal of an input side.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view of the piezoelectric transformer 100 in the present embodiment, and FIG. 2 is a horizontal sectional view (sectional view taken along the line II-II in FIG. 1) showing the piezoelectric transformer 100 in a completed state. is there. The piezoelectric transformer 100 is used for a high voltage power source such as an inverter for a liquid crystal backlight, for example, and generates a high voltage output with a low voltage input.

  As shown in FIG. 1, the piezoelectric transformer 100 mainly includes a piezoelectric ceramic (piezoelectric body) 102 and a resin case (case) 104, and the piezoelectric ceramic 102 is accommodated in the case 104. 1 corresponds to the bottom surface side of the case 104, and the piezoelectric transformer 100 is mounted with the bottom surface side of the case 104 facing the mounting surface of a circuit board (not shown). .

  The piezoelectric ceramic 102 of this embodiment is configured by polarizing a piezoelectric vibrator such as lead zirconate titanate ceramic (PZT). The shape of the piezoelectric ceramic 102 is not particularly limited, but here, as an example, a substantially rectangular parallelepiped shape (flat plate shape) can be given.

  A primary electrode (electrode) 106 is formed on each of the outer surfaces of the piezoelectric ceramic 102 that are paired in the thickness direction. Although only one side is shown in FIG. 1, a similar primary electrode (electrode) 106 is also formed on the opposite side (FIG. 2). Further, a secondary electrode 108 is formed on the rear end portion in the longitudinal direction of the outer surface of the piezoelectric ceramic 102. The secondary electrode 108 of the present embodiment is formed only on one surface (one surface shown in FIG. 1) which is paired in the thickness direction (FIG. 2).

  The primary electrode 106 and the secondary electrode 108 are formed on the outer surface of the piezoelectric ceramic 102 by, for example, screen printing using a metal paste, and are approximately in the width direction of the piezoelectric ceramic 102, that is, in the longitudinal direction and the thickness direction described above. When viewed in the orthogonal direction, the length is slightly shorter than the width of the piezoelectric ceramic 102. Note that the primary electrode 106 is formed with a length of about half of the entire length (longitudinal direction) of the piezoelectric ceramic 102.

  The resin case 104 has a case main body 104b whose bottom surface is opened, and has inner walls 104a and 104a extending from the bottom surface toward the upper surface of the case 104 (located downward in FIG. 1). . Although not shown in the figure, the opening of the case 104 in this embodiment is only on the bottom surface side, and the top surface side is closed. Further, these inner walls 104a are slightly longer than the total length of the piezoelectric ceramic 102, and the piezoelectric ceramic 102 is accommodated in the case main body 104b in a vertically placed posture (with the side end surface around the waist turned upside down). can do.

The resin case 104 is provided with recesses 104c, 104d, 104e, 104f at four locations in the case main body 104b. These four recesses 104c to 104f are all formed so as to scoop (depress) with a certain width from the inner wall 104a toward the outside of the main body 104b.
Of the recesses 104c to 104f, the two recesses (folders) 104c and 104d are arranged on the primary electrode 106 side, and are in a positional relationship facing each other with the piezoelectric ceramic 102 sandwiched in the main body 104b, and the recesses 104c and 104d are mutually connected. It is comprised by the same (symmetric) shape.

  Further, the concave portions 104c and 104d are formed at nodes of mechanical vibration (a position where the amplitude becomes zero) generated in the longitudinal direction of the piezoelectric ceramic 102. More specifically, the recesses 104c and 104d of this embodiment are provided at a position away from the front end portion in the longitudinal direction by λ / 4 with respect to the total length λ of the piezoelectric ceramic 102.

  This is because the piezoelectric ceramic 102 of this example is driven by the voltage of its natural resonance frequency (λ), and the vibration nodes at that time are λ / from the front end portion and the rear end portion in the longitudinal direction. Located 4 away. At the same time, mechanical vibrations are also generated in the width direction and the thickness direction described above, although they are smaller than the mechanical vibrations generated in the longitudinal direction. The vibration node in the width direction is at a substantially central position between the upper end portion and the lower end portion, and the vibration node in the thickness direction is also at a substantially central position between the tip portion and the end portion. is there.

  On the other hand, the concave portions 104e and 104f arranged on the secondary electrode 108 side are also in a positional relationship facing each other with the piezoelectric ceramic 102 interposed therebetween, but the concave portion 104e located on the near side in FIG. It has a larger shape than 104f. Moreover, since these recessed parts 104e and 104f are provided in the rear-end part of the longitudinal direction of the piezoelectric ceramic 102, a bigger output voltage can be obtained.

  The resin case 104 is provided with a total of three terminals 110, 112 and 114. Of these, the two terminals 110 and 112 are respectively disposed in the resin case 104 so as to face the primary electrode 106. On the other hand, the remaining terminals 114 are disposed in the resin case 104 so as to face the secondary electrode 108. These three terminals 110, 112, 114 are inserted into the case main body 104b from the upper surface side to the bottom surface side of the case 104, the side surfaces thereof are exposed in the recesses 104c, 104d, 104e, and the tips thereof are the bottom surface. Further protruding from the side.

  As described above, in the state where the piezoelectric ceramic 102 is accommodated in the case main body 104b, the above-described folder, that is, the two concave portions 104c and 104d that are paired with each other, have conductor blocks (elastic members) 116 and 116, respectively. It is installed, and another conductor block 120 is installed in the recess 104e. A block-like silicone rubber 122 is installed in the other recess 104f. The piezoelectric ceramic 102 is sandwiched between the two conductor blocks 116 and 116 and between the conductor block 120 and the silicone rubber 122 in a state of being floated from the upper surface side in the resin case 104. Held in a state.

  These conductor blocks 116 and 120 are made of a substantially rectangular parallelepiped rubber material having conductivity. In addition to the elasticity of silicone rubber as a base material, the conductor blocks 116 and 120 are each made of a conductive material kneaded therein. It also has. Accordingly, the primary electrode 106 and the secondary electrode 108 of the piezoelectric ceramic 102 and the terminals 110, 112, and 114 are electrically connected via the conductor blocks 116 and 120, respectively.

  The conductor blocks 116 and 116 are disposed in the resin case 104 between the primary electrode 106 of the piezoelectric ceramic 102 and the terminals 110 and 112, respectively. In other words, the front end portion of the conductor block 116 is in contact with the primary electrode 106 and the end portion thereof is in contact with the terminal 110 or the terminal 112. At this time, the conductor block 116 is fitted into the corresponding recesses 104c and 104d, and is compressed (press-fitted) between the primary electrode 106 and the terminals 110 and 112.

  More specifically, as shown in FIG. 3, the concave portion 104c of the present embodiment includes a support surface (positioning surface) 104h formed along the horizontal direction of the case 104, and both end portions of the support surface 104h. The case 104 has support surfaces 104q and 104q extending in the vertical direction, and the latter support surface 104q reaches the bottom surface side of the case 104.

  The supporting surfaces 104q and 104q facing each other constrain the side surface extending in the vertical direction of the case 104 among the four side surface portions of the conductor block 116, and the supporting surface 104h is the side surface portion of the block 116. Of these, the upper surface (located below in FIGS. 1 and 3) extending in the horizontal direction of the case 104 is constrained, and the concave portion 104c defines the conductor block 116 with a total of three support surfaces 104h, 104q, and 104q. To be held.

  Further, the support surfaces 104q and 104q are formed on the case main body 104b so that the center of the tip portion of the block 116 (the end surface portion facing the primary electrode 106) substantially coincides with the vibration node generated in the longitudinal direction of the piezoelectric ceramic 102. Is formed. Similarly, the support surface 104h is configured so that the center of the front end portion of the block 116 substantially coincides between the bottom surface side of the case 104 and the approximate center position of the primary electrode 106 when viewed in the width direction of the piezoelectric ceramic 102, for example. 104b is formed.

Similarly to the concave portion 104c, the concave portion 104d of the present embodiment also has a support surface (positioning surface) 104g formed along the horizontal direction of the case 104 and both ends of the support surface 104g in the vertical direction of the case 104. The support surfaces 104p and 104p each extend toward the surface.
The support surfaces 104p and 104p restrain the two side surfaces of the conductor block 116, the support surface 104g restrains the upper surface of the block 116 (located below in FIGS. 1 and 3), and the recess 104d The conductor block 116 is held by a total of three support surfaces 104g, 104p, and 104p.

  Further, these support surfaces 104p and 104p are also formed on the case main body 104b so that the center of the tip portion of the block 116 substantially coincides with the vibration node generated in the longitudinal direction of the piezoelectric ceramic 102, similarly to the support surface 104q. The support surface 104g is also formed on the main body 104b so that the center of the tip portion of the block 116 substantially coincides between the bottom surface side of the case 104 and the substantially central position of the primary electrode 106.

  In addition, as shown in FIG. 4, the concave portion 104e of the present embodiment also has a support surface 104i formed along the horizontal direction of the case 104 and the both ends of the support surface 104i in the vertical direction of the case 104. And support surfaces 104r and 104r extending respectively. These support surfaces 104r and 104r constrain the two side surfaces of the conductor block 120, respectively, and the support surface 104i constrains the upper surface of the block 120 (located below in FIGS. 1 and 4). The conductor block 120 is held by a total of three support surfaces 104i, 104r, and 104r.

Further, like the support surface 104g and the support surface 104h, the support surface 104i is formed such that the center of the tip portion of the block 120 is the bottom surface side of the case 104 and the substantially center position of the secondary electrode 108 when viewed in the width direction of the piezoelectric ceramic 102. The main body 104b is formed so as to substantially coincide with each other.
Since the secondary electrode 108 is formed only on one surface of the piezoelectric ceramic 102 as described above, only one conductor block 120 is required.

  However, since the conductor block 120 is compressed between the secondary electrode 108 and the terminal 114, considering the balance in the resin case 104, it is opposite to the secondary electrode 108 as in this embodiment. It is preferable to arrange the silicone rubber 122 also on the side surface. In other words, the silicone rubber 122 contributes to absorbing mechanical vibration of the piezoelectric ceramic 102 by sandwiching both surfaces of the piezoelectric ceramic 102 with the conductor block 120 in the case 104.

  Therefore, also for the recess 104f of the present embodiment, the support surface 104j formed along the horizontal direction of the case 104, and the support surfaces 104s extending from both end portions of the support surface 104j in the vertical direction of the case 104, respectively. 104s. These support surfaces 104s and 104s restrain the two side surfaces of the substantially rectangular parallelepiped silicone rubber 122, respectively, and the support surface 104j restrains the upper surface of the silicone rubber 122 (located below in FIGS. 1 and 4).

The support surface 104j is also formed on the main body 104b so that the center of the tip portion of the silicone rubber 122 substantially coincides between the bottom surface side of the case 104 and the substantially center position of the secondary electrode 108.
Here, the piezoelectric ceramic 102 of this example is fixed to the case 104 only on the primary electrode 106 side.

  Specifically, as shown in FIG. 5, on the upper surface side of resin case 104 (located below in FIGS. 1 and 5), a protruding guide rib (rib) that supports the thickness portion of piezoelectric ceramic 102. 104t, 104t are formed, and in the piezoelectric ceramic 102 of this embodiment, for example, a silicone adhesive (adhesive member) 124 is applied from the bottom surface side of the case 104 to the main body 104b.

  The application position of the adhesive 124 is substantially the same along the width direction of the piezoelectric ceramic 102 from the position where λ / 4 is separated from the front end portion in the longitudinal direction of the piezoelectric ceramic 102, that is, from the formation position of the concave portions 104c and 104d described above. It is on a straight line. This is because the vibration nodes generated in the longitudinal direction of the piezoelectric ceramic 102 exist in the width direction, in other words, on a straight line extending from the upper surface side to the bottom surface side of the case 104.

  Then, the applied adhesive 124 is held in the rib 104t, and then when the piezoelectric ceramic 102 is accommodated in the case main body 104b, the piezoelectric ceramic 102 adheres to the upper surface of the case 104 except for the adhesion portion on the primary electrode 106 side. It is fixed to the case 104 in a state of being lifted from the side (FIGS. 3 and 4). Thereafter, the piezoelectric ceramic 102 is held by the conductor blocks 116, 116, 120 and the silicone rubber 122 described above.

  When the conductor blocks 116 and 116 are mounted, when viewed in the width direction of the piezoelectric ceramic 102, buffer regions 104w and 104w are provided between the recesses 104c and 104d and the adhesive 124 as shown in FIG. Each is formed. Specifically, the buffer areas 104w and 104w are substantially rectangular regions formed in a part of the inner wall 104a above the support surfaces 104g and 104h (located below in FIGS. 1 and 3). The support surfaces 104g and 104h and the adhesive 124 are partitioned.

Incidentally, an opening may be formed on the upper surface side of the case 104 described above.
Specifically, the piezoelectric ceramics 102 shown in FIG. 6 is also fixed to the case 104 only on the primary electrode 106 side, as in the above embodiment, but in this embodiment, between the guide ribs 104t and 104t. In addition, an opening 104u is formed which penetrates the upper surface side of the case 104 and is visible from the outside of the piezoelectric ceramic 102, that is, from above the case 104 (downward in FIGS. 1 and 6).

As shown in FIG. 7, the opening 104 u is formed, for example, as a square hole, and has a size that allows only the vicinity of the piezoelectric ceramic 102 and the primary electrodes 106 and 106 to be visually recognized from the outside.
When the adhesive 124 is applied to the main body 104b from the opening 104u, the adhesive 124 is held in the rib 104t. Next, when the piezoelectric ceramic 102 is accommodated in the case main body 104 b, the piezoelectric ceramic 102 is fixed to the case 104 and then held by the conductor blocks 116, 116, 120 and the silicone rubber 122 described above.

  In the case of this embodiment, the piezoelectric ceramic 102 is accommodated in the case main body 104b and held by the conductor blocks 116, 116, 120 and the silicone rubber 122, and then the adhesive 124 is removed from the opening 104u through the main body 104b. It is also possible to apply it inside.

  As described above, according to this embodiment, the piezoelectric transformer 100 includes the piezoelectric ceramic 102 having the primary electrode 106 formed on the outer surface, and the piezoelectric ceramic 102 is accommodated in the resin case 104. The piezoelectric transformer 100 includes terminals 110 and 112 disposed so as to face the electrodes 106, and a conductor block 116 is disposed between the electrodes 106 and the terminals 110 and 112. The conductor block 116 has conductivity, and can contact both the electrode 106 and the terminals 110 and 112 so that they can be electrically connected to each other. As described above, when the conductor block 116 is used, there is no fear of disconnection of the gold thread wire due to mechanical vibration of the piezoelectric ceramic 102 or peeling of the connection portion due to soldering.

  Here, the piezoelectric transformer 100 includes concave portions 104c and 104d. The recesses 104c and 104d hold the conductor block 116 in the case 104, that is, hold the conductor block 116 in the case 104 so that the conductor block 116 does not move. Can be reliably disposed in a press-fitted state between the electrode 106 and the terminals 110 and 112.

  Therefore, for example, when the piezoelectric transformer 100 is assembled or when the piezoelectric transformer 100 is vibrated in the longitudinal direction of the piezoelectric ceramic 102, the position of the conductor block 116 is difficult to shift, and the electrode 106 and the terminals 110, 112 are not displaced. The position is reliably maintained between. The recesses 104 c and 104 d hold the conductor block 116 in the vicinity of a vibration node viewed in the longitudinal direction of the piezoelectric ceramic 102 generated by the primary electrode 106.

  On the other hand, the adhesive 124 fixes the piezoelectric ceramic 102 to the case 104 in the vicinity of a vibration node similarly generated by the primary electrode 106, and the buffer areas 104w, 104c, 104d are interposed between the adhesive 124 and the recesses 104c, 104d. 104w is formed. In other words, the application position of the adhesive 124 and the positions of the recesses 104c and 104d in which the conductor block 116 is disposed are separated by the buffer areas 104w and 104w. Therefore, the adhesive 124 having an insulating property is difficult to come into contact with the conductive block 116 having conductivity, and the block 116 can surely exert a conduction function between the electrode 106 and the terminals 110 and 112.

Moreover, if the adhesive 124 is fixed to the case 104 in the vicinity of the vibration node seen in the longitudinal direction of the piezoelectric ceramic 102 generated by the primary electrode 106, the adhesive 124 becomes a node generated on the side closer to the secondary electrode 108. As compared with the case where an adhesive is applied, the vibration of the piezoelectric ceramic 102 generated by the primary electrode 106 can be surely suppressed, and the wear of the conductor block 116 can be prevented.
As a result, the reliability of the piezoelectric transformer 100 is improved.

Further, when the adhesive 124 is used only for the primary electrode 106, the application work of the adhesive 124 is reduced as compared with the conventional case, and the amount of the adhesive 124 used can be reduced.
Further, the piezoelectric ceramic 102 is formed in a substantially rectangular parallelepiped shape composed of the longitudinal direction, the thickness direction, and the width direction, and the electrodes 106 are respectively formed on surfaces that make a pair in the thickness direction. The recesses 104c and 104d have support surfaces 104g and 104h, and the conductor block 116 is located between the upper surface side and the bottom surface side of the case 104 when viewed in the width direction via the support surfaces 104g and 104h. Placed in.

On the other hand, the adhesive 124 fixes the piezoelectric ceramic 102 to the case 104 on the upper surface side of the case 104, and buffer areas 104w and 104w are formed between the adhesive 124 and the support surfaces 104g and 104h. The
That is, buffer areas 104w and 104w are formed between the adhesive 124 and the support surfaces 104g and 104h on which the conductor block 116 is disposed, and the positional relationship between the adhesive 124 and the support surfaces 104g and 104h is clearer. Therefore, the adhesive 124 does not advance toward the conductor block 116, and the influence of the adhesive 124 does not appear on the block 116.

  Further, when the support surfaces 104g and 104h are formed between the bottom surface side of the case 104 and the substantially central position of the electrode 106 when viewed in the width direction, the conductor block 116 is placed at the deepest depth of the case 104 when the piezoelectric transformer 100 is assembled. As compared with the case where the conductor block 116 is inserted up to the portion, the conductor block 116 can be easily arranged in a press-fit state between the electrode 106 and the terminals 110 and 112.

Furthermore, since the adhesive 124 is held by the guide rib 104 t provided on the upper surface side of the case 104, the adhesive 124 is more difficult to advance toward the conductor block 116.
As shown in FIGS. 6 and 7, an opening 104 u penetrating the case 104 is formed on the upper surface side of the case 104, and the opening 104 u is configured so that the piezoelectric ceramic 102 can be seen from the outside. Therefore, the adhesive 124 can be applied toward the inside of the case 104 before or after the piezoelectric ceramic 102 is accommodated in the case 104, and the adhesive 124 is directed from the bottom surface side to the top surface side of the case 104. Work becomes easier as compared with the case of coating.

In addition, since the adhesive 124 is difficult to contact the terminals 110 and 112 that require conduction in addition to the conductor block 116, the influence of the adhesive 124 does not appear on the terminals 110 and 112. Whether or not the coating operation is completed is also clarified from the opening 104u.
Further, if the size of the opening 104u is formed so that only the vicinity of the piezoelectric ceramic 102 and the electrodes 106 and 106 can be seen from the outside as viewed in the thickness direction of the piezoelectric ceramic 102, the openings 104c and 104d are formed. In contrast, the adhesive 124 hardly progresses toward the conductor block 116 as compared with the case where the adhesive 124 is formed in a size visible from the outside.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. For example, a part of the configurations of the above embodiments can be omitted or arbitrarily combined so as to be different from the above.
In the above embodiment, the support surfaces 104g and 104h are disposed between the bottom surface side of the case 104 and the substantially central position of the electrode 106 when viewed in the width direction, but the present invention is not necessarily limited to this form. That is, as long as the buffer area 104w is provided, the support surfaces 104g and 104h are arranged in a longitudinal direction of the piezoelectric ceramic 102 that exists on a straight line from the upper surface side to the bottom surface side of the case 104, such as the approximate center position of the electrode 106. It may be arranged at a node of vibration generated in

  Further, the configuration of the conductor block 116 is not limited to the above-described embodiment. For example, the block 116 has an electrically conductive member as an intermediate layer and elastic holding members on both sides along the longitudinal direction of the piezoelectric ceramic 102. Each of the holding layers may be provided, or the conductive rubber layer and the silicone rubber layer may be laminated in the width direction of the piezoelectric ceramic 102 (zebra structure).

  Further, these conductor blocks 116 may be made of different conductive materials. Further, the primary electrodes 106 of this embodiment are respectively formed on surfaces that make a pair in the thickness direction of the piezoelectric ceramic 102. However, like the secondary electrode 108, this electrode 106 may be formed only on one of the surfaces paired in the thickness direction, and the above-described conductor block is disposed only on the surface having this electrode. However, the above-described silicone rubber may be disposed on the surface having no electrode, and the piezoelectric ceramic 102 may be sandwiched between the conductor block and the silicone rubber.

The piezoelectric transformer of the present invention can naturally be used for high-voltage power supplies such as dust collectors, copiers, facsimile machines, ion generators, ozone generators, in addition to the above-described inverter for liquid crystal backlights.
In any of these cases, similarly to the above, there is an effect that the adhesive does not hinder the conduction between the primary electrode and the terminal.

It is a disassembled perspective view of the piezoelectric transformer in a present Example. FIG. 2 is a horizontal sectional view showing the piezoelectric transformer of FIG. 1 in a completed state. It is arrow sectional drawing seen from the III-III line | wire of FIG. It is arrow sectional drawing seen from the IV-IV line of FIG. It is arrow sectional drawing seen from the VV line | wire of FIG. It is a principal part enlarged view of the resin case in another Example. It is the top view which looked at the resin case of FIG. 6 from upper direction.

Explanation of symbols

100 Piezoelectric transformer 102 Piezoelectric ceramics (piezoelectric material)
104 Resin case
104c, 104d recess (folder)
104g, 104h Support surface (positioning surface)
104t guide rib (rib)
104u Opening 104w Buffer area 106 Primary electrode (electrode)
110, 112 terminal 116 conductor block (elastic member)
124 Adhesive (adhesive member)

Claims (5)

A piezoelectric body having an input side electrode formed on the outer surface;
A case for accommodating the piezoelectric body;
A terminal disposed opposite the electrode;
An elastic member having electrical conductivity that contacts both of the electrode and the terminal in the case and electrically connects them;
A folder that is formed in the case, holds the elastic member near the vibration node of the piezoelectric body, and press-fits the elastic member between the electrode and the terminal; and
An adhesive member having an insulating property to fix the piezoelectric body to the case in the vicinity of a vibration node of the piezoelectric body;
Comprising a buffer area formed between the adhesive member and the folder ;
While the piezoelectric body is configured in a substantially rectangular parallelepiped shape, the electrode is formed on at least one of the surfaces that make a pair in the thickness direction of the piezoelectric body,
The folder includes a positioning surface for disposing the elastic member between an upper surface side and a bottom surface side of the case as viewed in a width direction substantially orthogonal to the longitudinal direction and the thickness direction of the piezoelectric body, and the bonding The member fixes the piezoelectric body to the case on the upper surface side of the case,
The piezoelectric transformer, wherein the buffer region is formed between the adhesive member and the positioning surface. The piezoelectric transformer according to claim 1 ,
The piezoelectric transformer, wherein the positioning surface is formed between a bottom surface side of the case and a substantially central position of the electrode when viewed in the width direction of the piezoelectric body. The piezoelectric transformer according to claim 1 or 2 ,
A piezoelectric transformer, wherein a rib for holding the adhesive member is provided on an upper surface side of the case. The piezoelectric transformer according to any one of claims 1 to 3 ,
A piezoelectric transformer, wherein an opening is formed on the upper surface side of the case so as to penetrate the case and allow the piezoelectric body to be visually recognized from the outside. The piezoelectric transformer according to claim 4 ,
The piezoelectric transformer is characterized in that the opening is formed in such a size that only the vicinity of the piezoelectric body and the electrode can be seen from the outside when viewed in the thickness direction of the piezoelectric body.

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