JPH05113553A - Acoustic optical element - Google Patents

Abstract

PURPOSE:To easily connect an element main body and a matching circuit part, to prevent disconnection or the like at a connection part from occurring, to enhance reliability and improve an electric characteristic. CONSTITUTION:A joining part 15 obtained by forming and aligning the pad parts of a third electrode 3 and a fourth electrode 4 is provided on a circuit substrate 10. It is preferable that the matching circuit part 11 is integrally formed. By making the joining part 15 of the substrate 10 abut on the electrode surface of the piezoelectric body 6 of an acoustic optical medium 7 and closely bringing the pad parts of the electrodes into contact with a second electrode 2 and a fifth electrode 5 on the piezoelectric body, the electrical conduction and the connection thereof are simultaneously executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acousto-optic device used in, for example, a color printing plate making machine, and more particularly to improvement of a connection structure between a device body and a circuit board.

[0002]

2. Description of the Related Art An acousto-optic device (hereinafter, abbreviated as AO device) is a device for diffracting laser light by utilizing an acousto-optic effect. FIG. 9 shows a first conventional example. In this case, an acousto-optic medium 7 that propagates an ultrasonic wave, and a piezoelectric body 6 that generates an ultrasonic wave and is provided on one end surface of the acousto-optic medium 7 via the first electrode 1 (grounding ground electrode), A second electrode 2 (signal voltage applying electrode) that is attached to the surface of the piezoelectric body 6 and is insulated from the first electrode 1, and the impedance of an external drive circuit connected to these two electrodes. The matching circuit unit 11 for carrying out the matching is mounted.

As the acousto-optic medium 7, PbMoO ₄ ,
Crystal materials such as TeO ₂ , LiNbO ₃ and GaP, or synthetic quartz glass, chalcogenide glass, Te glass, etc. are used. Further, as the piezoelectric body 6, Li
A piezoelectric material such as NbO ₃ or ZnO is used, and is attached to the polished surface of the acousto-optic medium 7 via the first electrode 1.

10 to 11 show a second conventional example. In this case, the member connecting the acousto-optic medium 7 and the matching circuit section 11 is composed of a plurality of elongated metal plates 25, one end of which is arranged parallel to the surface of the piezoelectric body 6 at a predetermined interval and the other end of which is arranged. It is bent and connected to the matching circuit section 11 via the solder 26. Further, a plurality of lead wires 21 are provided on the first electrode 1 in a one-to-one correspondence with these metal plates 25, one end of which is connected to the first electrode 1 via a silver paste 22 and the other. The end portion is connected to the matching circuit portion 11 via the solder 20.

As shown in FIG. 11, one end of the metal plate 25 is alternately protruded from the left and right on the piezoelectric body 6 and arranged in parallel at a predetermined interval. Further, one end of the lead wire 21 is arranged between these metal plates 25, and is connected to the first electrode 1 protruding around the piezoelectric body 6 by the silver paste 22. After arranging the metal plates 25 in this manner, the metal plate 25 is attached by pressure contact with the surface of the piezoelectric body 6 by the pressing plate 13 shown in FIG.

[0006]

In the conventional AO element,
Element body (acousto-optic medium and piezoelectric body, etc.) and matching circuit section 11
There is a method of connecting all the lead wires as shown in FIG. 9 or a combination of the metal plate 25 and the lead wires as shown in FIG. However, in each method, the wiring is individual and the number of soldering points is large. There is a possibility that the wires will be cut by applying force one by one to the disjointed wires. In addition, soldering and conductive paste are used to manually connect at one place, and the work itself is complicated and the finished product is likely to be unstable. Further, there is a problem that the impedance between wirings and the line impedance of each wiring are not constant.

For example, since the metal plate 25, which is a wiring member, is made of a thin metal having a thickness of about 0.1 mm, it may be broken or cut in the middle. In addition, the lead wire 21
Also, since the diameter is about 0.7 mm, which is a thin line, there is a possibility of cutting in the middle. Therefore, it has been a cause of lowering the reliability of the element.

Therefore, an object of the present invention is to improve the workability of the connection work by facilitating the connection between the element body and the matching circuit portion, and to suppress the failure such as disconnection in the circuit connection to improve the reliability of the element. Another object of the present invention is to provide an AO element which is enhanced and has improved electrical characteristics.

[0009]

In order to achieve the above object, the present invention provides an acousto-optic medium for propagating ultrasonic waves and an ultrasonic wave provided on one end surface of the acousto-optic medium via a first electrode. A piezoelectric body to be generated, an island-shaped second electrode is provided on a surface of the piezoelectric body opposite to the first electrode of the piezoelectric body, and a third electrode conductively connected to the second electrode is formed. A circuit board provided with a fourth electrode conductively connected to the first electrode;
In an acoustooptic device including a matching circuit conductively connected to these third and fourth electrodes, the first electrode is separated from the second electrode on the side of the piezoelectric body where the second electrode is provided. A fifth electrode conductively connected to the fifth electrode, the fourth electrode is provided at a position facing the fifth electrode, and the third electrode is provided at a position facing the second electrode. This circuit board is brought into contact with one end surface on the acousto-optic medium, and the second electrode and the third electrode, and the fifth electrode and the fourth electrode are both brought into close contact and conductively connected. It is characterized by being done.

According to the present invention, the patterns of the third and fourth electrodes of the circuit board are formed in a pad shape so that their ends can be connected by a close contact, and the electrode pads are aligned. This portion of the circuit board constitutes a joint, and after being aligned with the second and fifth electrodes on the piezoelectric body, they are brought into close contact and conductively connected. If necessary, a pressing plate is pressed from the back side of the circuit board that is in contact. It is mechanically fixed after the connection is stable.

In the present invention, preferably, the circuit board is the third
The fourth electrode pad portion is formed and aligned, the joint portion, the electrode lead portion leading to the matching circuit portion, and the matching circuit portion are integrally mounted.

A resin coating is applied to a portion of the surface of the circuit board excluding the joint portion for protection and insulation.

[0013]

In the present invention, the two electrodes, that is, the second electrode, are formed on the piezoelectric body.
And a fifth electrode are provided, and a circuit board provided with the third and fourth electrodes at positions opposed to these is used, and the circuit board is aligned with and brought into contact with the electrodes on the piezoelectric body.
All electrodes and lead wires in the prior art can be connected in one operation, the time of connection operation can be greatly simplified, and the yield is improved without failure.

Further, since the connecting method is performed by the close contact, it is possible to redo the work itself in a short time as compared with the conventional method of connecting with the conductive paste or the solder. The electrical characteristics can be immediately obtained after assembly in the production process, and as a result, defective parts can be detected on the spot to quickly obtain a finished product having a normal function.

Further, since the circuit board and the acousto-optic medium portion can be immediately separated due to the connection by the close contact, even if each portion is damaged, the defective portion can be replaced and the reassembly can be easily performed. It can be said that the maintainability in the market is good.

Further, by using the circuit board in which all the electrodes are in close contact with each other and the electrode patterns are integrally formed, the electrodes and the lead wires are broken as compared with the case where the plurality of electrodes and the lead wires are individually connected. The risk of occurrence is extremely reduced, the mechanical strength is improved, and the reliability of the element can be improved.

In the acousto-optic element, RF power for heat generation, that is, laser light control to be applied to the piezoelectric body (for example, a frequency of about 100 MHz and 0.1 per electrode) is used.
It is preferable to consider generation of heat due to electromechanical conversion loss or the like in the piezoelectric body of about 0.5 watts). In the present invention, not only the second electrode but also the fifth electrode connected to the first electrode which is the ground electrode of the piezoelectric body has a large area and is connected to the circuit board side at a very short distance. Preferably. As a result, the heat generation source can be conductively connected in a wider area as compared with the conventional technique in which individual wiring is used for the wiring of the electrodes. Therefore, active dissipation of unnecessary heat can be achieved. As described above, the improvement of the temperature of the element and the cooling of the element have been dramatically improved.

Among the conventional techniques, there is a method of cooling the acousto-optic medium from the lower portion (non-piezoelectric body side). Even in comparison with this, it is possible to cause the heat generation source to transfer heat over a wider area, dissipate the heat from the electrode surface side, and prevent the heat from being transferred to the acousto-optic medium side. It is overwhelmingly superior in that it eliminates the cause of failure from its root. For example, in a 10-channel acousto-optic device, the temperature of the electrode part may rise from 40 ° C. to about 50 ° C. depending on other conditions. According to the invention,
It is possible to suppress a temperature rise from room temperature of about 5 ° C to 15 ° C. An average improvement of about 10 ° C can be expected. First
If the circuit board electrically conductively connected to the fifth electrode section is provided with another auxiliary cooling means such as water cooling or electronic cooling, the temperature can be further improved and the temperature rise can be suppressed within 5 ° C.

Further, in the present invention, the heat is well dissipated, the heat is not stored inside the acousto-optic medium (crystal), the temperature of the acousto-optic medium does not rise so much, and the temperature of the acousto-optic medium is stable. Therefore, when the laser light is transmitted by the on / off switching operation, that is, when the laser light goes straight without being diffracted, the temperature of the acousto-optic medium rises, or the laser light changes due to the refractive index fluctuation due to the local temperature distribution. Offset diffraction is small. As a result, the insertion loss of light as a signal is reduced. Also, the variation in the diffraction angle of the laser light is reduced,
Accuracy is improved.

As described above, since unnecessary heat is dissipated, as compared with the prior art, for an acousto-optic device of the same size,
A larger RF power can be input, and as a result, the diffraction angle of laser light can be increased.

Since the circuit from the electrodes on the piezoelectric body to the matching circuit has a constant structure rather than discrete individual wiring, there is no characteristic variation between products and the electrical characteristics of the matching circuit are constant. The adjustment (adjustment) became easy, and the desired characteristics were easily obtained.

Since the second electrode and the fifth electrode on the acousto-optic medium can be formed simultaneously by vapor deposition of a metal such as gold (Au), no additional production process is required.
Further, when the metal film is formed, the relative positional accuracy and the dimensional accuracy can be sufficiently ensured, so that the dimension between the electrode itself and the electrode can be reduced.

According to the present invention, the joint portion in which the third electrode pad portion and the fourth electrode pad portion provided on the circuit board are aligned, the lead portions of these electrodes, and the matching circuit portion are integrally mounted. It is also possible to use the flexible substrate described above. With this, the connection work can be further omitted,
The number of steps required for assembly can be reduced, and the reliability of the device can be further improved.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A according to the present invention will now be described with reference to FIGS.
An example of the O element will be described. In addition, as shown in FIG.
The same reference numerals are given to the substantially same parts as 11 for the description.

1 to 3 show partial views of the first embodiment of the present invention. First, FIG. 1 is a side view of an AO element and shows a connection mode. In this figure, only the main part is shown, and the housing and other parts are not shown. FIG. 2 is a plan view of the AO element body viewed from the piezoelectric surface. FIG. 3 is a plan view of the flexible circuit board.

As can be seen from FIGS. 1 to 3, this AO
The element includes a flexible circuit board 10 in which a matching circuit portion 11 and a joint portion 15 are integrated. The bonding portion 15 is provided with electrode pads of the third electrode 3 (signal voltage application electrode) and the fourth electrode 4 (ground potential electrode) aligned with each other. Inexpensive copper foil was used for the pattern of these electrode lead portions, but the pad-like portion provided in the joint portion 15 was subjected to gold surface treatment so as not to deteriorate. The base material of the flexible circuit board 10 is semitransparent so that the electrode surface of the piezoelectric body 6 can be seen.

As shown in FIG. 1, with the electrode pad forming surface of the joint portion 15 of the flexible circuit board 10 facing downward,
The electrodes are aligned with the electrodes provided on the piezoelectric body 6 attached to the acousto-optic medium 7. The flexible circuit board 10 is pressed and fixed from the non-electrode surface side with the pressing plate 13 made of a material having good heat conductivity such as aluminum. in this case,
The flexible circuit board 10 can be easily aligned with the electrodes by being semitransparent.

Alternatively, a notch or hole for alignment is provided in the joint portion 15, and the notch and the position are formed at the same time as the second and fifth electrodes provided on the periphery of the first electrode surface or the piezoelectric facing surface. You may make it match. In this way, the second electrode 2 and the third electrode 3 are in close contact with the fourth electrode 4, and the fifth electrode 5 and the fourth electrode 4 are in close contact with each other for connection. Matching circuit section 11
Is integrally formed on the flexible circuit board 10 and the joint portion 15, so that the connecting work to the matching circuit is omitted.

As shown in FIG. 2, in the present invention, the fifth electrode 5 is provided from the first electrode 1 (grounding ground electrode) to the piezoelectric surface. The fifth electrode 5 is conductively connected to the first electrode 1 and is connected to the joint portion 1 of the circuit board 10.
5 is located at a position facing the fourth electrode 4 provided on
It is in close contact. The fifth electrode and the second on the acousto-optic medium 7 side
The electrodes can be simultaneously formed by vapor deposition of a metal film or the like. The close contact with the opposing electrodes is mainly performed on the surface of the piezoelectric body 6 where the two electrodes have substantially the same height.

As shown in FIG. 3, the end portions of the electrode patterns of the third electrode 3 and the fourth electrode 4 are formed in a pad shape, and these electrode pad portions are arranged and provided. Although these electrode pad portions are exposed so as to be in close contact with each other, the resin coating layer 12 is provided except for these portions.
(Hatched portion) is provided. As the coating material, for example, polyimide, resist, etc. are used,
Since polyimide requires adhesiveness, a thickness of 50 μm or more is required, whereas a resist may have a thickness of about 8 to 10 μm. Therefore, in order to improve flexibility, a resist is more preferably adopted. It

As shown in FIG. 1, the pressing plate 13 is sandwiched between the flexible circuit board 10 and the second electrode 2 on the piezoelectric body.
By closely contacting the second electrode 5 and the fifth electrode 5, a heat dissipation effect can be obtained from that portion as well, and the occurrence of a refractive index distribution due to the temperature distribution of the AO element can be suppressed, and the light transmission characteristics can be further improved. it can. As the material of the push plate 13, a metal such as aluminum or a ceramic material having good thermal conductivity can be used.

FIG. 4 is a plan view of the flexible circuit board 10 according to the second embodiment of the present invention. Here, the number of the third electrodes 3 is 10 (10 pieces of laser light can be diffracted), and accordingly, the number of the fourth electrodes 4 is also 10.
The joint portion 15 in which the electrode pad portions that are in close contact are arranged and provided is exposed. A resin coating layer 12 is provided on the other portions to protect the electrode pattern. In addition, the electrode patterns for each set are distributed to the left and right.

5 to 6 show a third embodiment of the present invention. FIG. 5 is a side view showing a connection mode. In this embodiment, a flexible circuit board 10 having double-sided wiring is used. Third
The lead portion of the electrode 3 and the lead portion of the fourth electrode 4 are provided by selectively using the front surface and the back surface of the flexible circuit board 10. The through hole 23 connects the electrode pad portion of the third electrode 3 and the lead portion provided on the opposite surface of the circuit board. A resin coating layer 12 is provided between the push plate 13 and the flexible circuit board 10.
Is insulated by. This resin coating layer 12
If not used, an insulating spacer having good thermal conductivity is provided instead.

FIG. 6 shows a plan view of the flexible circuit board 10 and the acousto-optic medium 7 in this embodiment. In this embodiment, the area of the ground potential electrodes (fifth and fourth electrodes) can be made larger, so that the electrical characteristics and the heat radiation effect are further improved. Further, the circuit board 10 and the third electrode pattern can be configured by a microstrip method so as to be suitable for high-frequency signal transmission.

7 to 8 show a fourth embodiment of the present invention. In the present embodiment, the circuit board 10 is configured mainly with the joint portion 15. It is separated from the matching circuit section 11 (not shown) and is connected by another wiring member 24. FIG. 8 shows a circuit board 1.
0 shows a plan view of the acousto-optic medium 7 viewed from the piezoelectric surface.
As the wiring member 24, a flexible substrate, a high frequency coaxial wire, or the like is used. The wiring member 24 and the circuit board 10 are connected by solder or a connector. Circuit board 1
In addition to the glass epoxy substrate, a ceramic substrate having a high thermal conductivity, an aluminum nitride substrate, or a flexible substrate similar to that of the above embodiment is used for 0. Circuit board 10
In addition to the joint portion 15, an external lead-out electrode pad portion 29 and the like are provided for connection with the wiring member 24.

[0036]

As described above, according to the present invention,
The third electrode 3 and the fourth electrode 4 are provided on the circuit board 10 connected to the matching circuit section 11, and the third electrode 3 and the fourth electrode 4 are brought into contact with the surface of the acousto-optic medium 7 on which the piezoelectric body 6 is provided, Since the second electrode 5 and the fifth electrode 5 on the piezoelectric body are brought into intimate contact with each other to make the conductive connection, it is possible to make a plurality of circuit connections at the same time, and the manufacturing workability is significantly improved. it can.

Further, since the circuit board 10 in which the electrodes and lead wires are pad-shaped or patterned is used, the wiring is not individual but integrated and the strength is improved. The reliability against connection failure, disconnection, etc. is dramatically improved as compared with the conventional product, and the reliability of the element can be enhanced.
Further, since the connection is made to the acousto-optic medium 7 without using any conductive paste or solder, there is no fear of contaminating the clean surface through which the laser beam passes, and the assembly process can be easily performed.

When the flexible circuit board 10 or the like in which the matching circuit portion 11 and the joint portion 15 are integrated is used,
It is not necessary to solder to the matching circuit board, and workability and reliability can be further improved.

Furthermore, since the second electrode 5 and the fifth electrode 5 on the piezoelectric body on the acousto-optic medium can be provided at the same time in the step of forming a metal film of gold (Au) or the like, the manufacture is easy, In addition, the accuracy can be ensured, and the size between the electrodes and the electrodes themselves can be reduced. Further, the electrodes can be provided to the maximum extent within the limited size of the piezoelectric body on the acousto-optic medium. Alternatively, the number of channels can be increased by making the electrodes smaller in accordance with the thin laser beam diameter.

Further, as compared with the conventional individual wiring, the inter-wiring impedance and the line impedance are constant, so that the variation between products can be reduced and the matching circuit can be easily adjusted. Further, the variation in performance as an acousto-optic device has been reduced, and it has become possible to provide better products to the market. When the signal lines of the third and fourth electrodes are formed of microstrips as in the third embodiment, transmission loss is reduced, noise is reduced, and electrical characteristics are further improved.

Heat generation is a problem peculiar to the acousto-optic device. In the present invention, since the electrode portion on the acousto-optic medium 7 and the electrode portion on the circuit board 10 are brought into close contact with each other, a thin lead wire is not used at all. Therefore, the heat is immediately transferred from the electrode widely contacting the piezoelectric body, which is the main heat generation source, to the electrode on the circuit board, and is radiated from the wider surface of the circuit board, so that the cooling effect is remarkable. Therefore, the temperature of the acousto-optic medium is constant around room temperature and the offset diffraction of the laser light is small. Further, the variation of the diffraction angle is reduced, and the accuracy is improved.

Further, because of this heat dissipation effect, it becomes possible to use a larger RF power for the ultrasonic waves for control as compared with the acousto-optic medium of the same size.
Therefore, the diffraction angle of the laser light can be increased.

[Brief description of drawings]

FIG. 1 is a side view of an acousto-optic device according to a first embodiment of the present invention, showing a mode of joining a circuit board and an acousto-optic medium.

FIG. 2 is a plan view of the acousto-optic medium of the first embodiment as viewed from the piezoelectric body attachment surface side.

FIG. 3 is a plan view showing an electrode pattern on a flexible circuit board according to the first embodiment.

FIG. 4 is a partially enlarged plan view of a flexible circuit board according to a second embodiment of the present invention.

FIG. 5 is a partial side view of an acousto-optic device according to a third embodiment of the present invention, showing a joint mode between a circuit board and an acousto-optic medium.

FIG. 6 is a partial plan view of a flexible circuit board and an acoustooptic medium according to a third embodiment.

FIG. 7 is a partial side view of an acousto-optic device according to a fourth embodiment of the present invention, showing a mode of joining a circuit board and an acousto-optic medium.

FIG. 8 is a partial plan view of a circuit board and an acoustooptic medium according to a fourth embodiment.

FIG. 9 is a side view showing an acousto-optic device of a first conventional example.

FIG. 10 is a side view showing an acoustooptic device of a second conventional example.

FIG. 11 is a plan view of the acousto-optic medium of the second conventional example as viewed from the piezoelectric body attachment surface side.

[Explanation of symbols]

 1 1st electrode (grounding ground electrode) 2 2nd electrode (signal voltage application electrode) 3 3rd electrode (on circuit board) 4 4th electrode (on circuit board) 5 5th electrode 6 Piezoelectric body 7 Acousto-Optical Medium 10 Circuit Board 11 Matching Circuit Section 12 Resin Coating Layer 13 Push Plate 14 Block Material 15 Joining Section 20 Solder (For Lead Wire Connection) 21 Lead Wire 22 Silver Paste 23 Through Hole 24 Wiring Member 25 Metal Plate 26 Solder ( 27) Electrode lead part 28 Electrode pad part 29 External extraction electrode pad part (on circuit board)

Claims (4)

[Claims] 1. An acousto-optic medium for propagating ultrasonic waves, a piezoelectric body provided on one end face of the acousto-optic medium via a first electrode to generate ultrasonic waves, and a first electrode of the piezoelectric body. Is provided with an island-shaped second electrode on the opposite piezoelectric surface.
A circuit board provided with a third electrode conductively connected to the first electrode and a fourth electrode conductively connected to the first electrode, and a matching circuit conductively connected to the third and fourth electrodes. An acousto-optic device including: a fifth electrode that is isolated from the second electrode on the side of the piezoelectric body where the second electrode is provided, and that is electrically conductively connected to the first electrode; On the acousto-optic medium, using a circuit board having the fourth electrode provided at a position facing the second electrode and the third electrode provided at a position facing the second electrode. An acousto-optic device, wherein one end face is brought into contact with the second electrode, the third electrode, and the fifth electrode and the fourth electrode are conductively connected to each other by a close contact. 2. The acousto-optic device according to claim 1, wherein the matching circuit is provided on the circuit board. 3. The acousto-optic device according to claim 1, wherein the circuit board is a flexible board. 4. The acoustooptic device according to claim 1, wherein a plurality of the second electrodes are provided.