JPH06350314A - Laser trimming device for adjusting resonance requency of dielectric resonator - Google Patents

Abstract

PURPOSE:To attain trimming at a high speed with high accuracy by measuring the initial resonance frequency of a dielectric resonator being a processing object and deciding a removed area of a surface electrode to be trimmed depending on a difference from an object frequency corrected by trimming. CONSTITUTION:Dielectric resonators 1 are carried in a line while the direction is being selected and they are fed to a 1st turntable 2 and a 2nd turntable 3 sequentially. Four-stop index tables are adopted for the tables 2, 3 and they are driven in the reverse direction as shown by the arrow. Then the oscillator (not shown) to generate a laser beam 4 used for trimming is arranged on a line tying the rotation center of the tables 2, 3 and each resonator 1 is trimmed by using positions 5, 6 provided to the tables 2, 3 as an index. The resonance frequency of the resonator 1 is measured at any time by using antenna measurement terminals 7, 8 and 9, 10 provided around the tables 2, 3 and the resonator 1 is trimmed and turned by 90 deg. and taken out after the measuremet is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser trimming device for adjusting the resonance frequency of a dielectric resonator for adjusting the resonance frequency of a dielectric coaxial resonator used in a dielectric filter used in mobile communication equipment and the like. It is a thing.

[0002]

2. Description of the Related Art Adjustment of the resonant frequency of a dielectric resonator is performed by reducing the electrode area on the surface of the dielectric resonator until the target frequency is reached for products having a resonant frequency below the target frequency. Among them, the resonance frequency used for a communication device or the like is usually in the range of several hundred megahertz to several gigahertz, and it is necessary to adjust the frequency variation to about 0.1% by frequency trimming.

Conventionally, a grinding process using a small cylindrical grindstone has been used as such trimming means, and a manual work for grinding until a target frequency is reached has been mainly performed.
In recent years, instead of manual work, an automatic trimming device has been proposed and put into practical use, which automatically supplies a dielectric resonator and grinds it to a desired frequency. Here, as a description of this automatic trimming device, the technical contents disclosed in Japanese Patent Laid-Open No. 3-214904 will be described.

FIG. 10 is a perspective view of an essential part of an example of such a conventional resonance frequency automatic trimming device for a dielectric resonator. In FIG. 10, the dielectric resonator 29 is a chuck 3.
It is ground by a cylindrical grindstone 32 which is sandwiched by 0 and attached to a spindle motor 31. In addition, the dielectric resonator 29
The resonant frequency of is measured by the antenna measurement terminal 33 in a non-contact manner by capacitively coupling. Further, the spindle motor 31 is mounted on a uniaxial NC table (not shown), performs arithmetic processing from the difference between the target frequency and the current frequency, and moves the uniaxial NC table, that is, the grindstone 32.
It is designed to control the cut length of. This arithmetic expression is a simple one assuming that the cutting length of the grindstone and the amount of change in the resonance frequency have a linear function relationship, and is calculated by the cutting length of the grindstone = (target frequency−current frequency) × coefficient.

[0005]

However, although there is an arithmetic expression for predicting the cutting length of the grindstone 32 in the above-mentioned conventional configuration, in the actual device, the cutting length of the grindstone 32 is the feed amount of the grindstone 32 and the start of grinding. This is a difference in position, and the grinding start position is a physical quantity that changes over time due to wear of the grindstone 32 and the like, and there is a problem that it is difficult to incorporate it into an arithmetic expression. Therefore, when the frequency adjustment of the dielectric resonator 29 is performed, a series of operations of grinding and measuring the resonance frequency results in being repeated many times, and when the trimming is excessively performed and the target frequency exceeds the limit, This is because the cut length of the grindstone 32 is always calculated as an underestimated tendency for safety, because it becomes impossible to adjust and a defective product is obtained. Further, since a processing method involving physical contact called grinding is used, it is necessary to bring the grindstone 32 rotating at high speed into contact with the dielectric resonator 29 at a relatively low speed in order to prevent chipping.

Further, a measuring instrument called a network analyzer, which is usually accompanied by a frequency sweep, is used for measuring the resonance frequency, but the time required for this measurement is relatively long, ie, several hundreds of milliseconds per time. The problem was that the time was long and the number of products produced per minute was about several, resulting in low productivity.

The present invention is intended to solve such a conventional problem, and an object thereof is to provide a laser trimming device for adjusting a resonance frequency of a dielectric resonator capable of performing high-speed and highly-accurate trimming. It is what

[0008]

In order to solve the above-mentioned problems, a laser trimming device for adjusting the resonance frequency of a dielectric resonator according to the present invention comprises a supply unit for supplying the dielectric resonator,
A table part that holds the supplied dielectric resonator and rotates intermittently, a measurement part that measures the resonance frequency of the dielectric resonator held on the table part, a trimming area and a resonance frequency change amount that are stored in advance. An arithmetic unit that determines the trimming amount of the dielectric resonator measured by the measuring unit based on an algorithm that predicts the trimming area of the dielectric resonator from the relationship, and a surface electrode of the dielectric resonator based on the result of the arithmetic unit. Is composed of a laser oscillator having an optical system for scanning and trimming from a corner end to a position having a required area, and a control unit for controlling these.

[0009]

With this configuration, the dielectric resonator to be processed has an initial resonance frequency measured by a resonance frequency measuring device, and the dielectric resonance is measured experimentally in advance according to the difference between the initial resonance frequency and the target frequency corrected by trimming. Laser trimming is performed after determining the removal area of the surface electrode using an algorithm that predicts the area to be trimmed for each dielectric resonator from the relationship between the obtained trimming area and the resonance frequency change amount of the dielectric resonator. This makes it possible to perform high-speed, high-precision and efficient trimming.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a main part showing a configuration of a laser trimming device for adjusting a resonance frequency of a dielectric resonator according to the same embodiment. In FIG. 1, reference numeral 1 denotes a dielectric resonator. 1 is sorted by direction by an appropriate supply means and aligned and transported, and the dielectric resonator 1 at the leading end of the transport is arranged by symmetrically placed on both sides of the transport system by the appropriate transfer means. 2 turntable 3 is supplied. The first turntable 2 and the second turntable 3 are 4-stop index tables and rotate intermittently in the direction shown by the arrow. Reference numeral 4 denotes a laser beam, which includes a laser oscillator 11 to a laser beam scanner 12 and a condenser lens 1 which will be described later in detail with reference to FIG.
The laser beam scanner 12 and the condenser lens 13 irradiate the dielectric resonator 1 via the center point 3 of the line connecting the rotation centers of the first turntable 2 and the second turntable 3. Are placed on top of.

The position 5 of the first turntable 2 and the position 6 of the second turntable 3 are stations for trimming, and the dielectric resonator 1 is laser-trimmed at the positions 5, 6. Further, at this time, the dielectric resonator 1 has its resonance frequency measured at the antenna measurement terminals 7, 8 and 9 and 10 at any time, and the dielectric resonator 1 after laser trimming is further rotated by 90 degrees so that it can be taken out. It is configured.

FIG. 2 is a block diagram showing the functional arrangement of the above-mentioned embodiment. In FIG. 2, 11 is an Nd-YAG laser oscillator with an ultrasonic Q switch, and the laser beam 4 generated from this is a laser beam scanner. Condensation scanning can be performed at an arbitrary position by 12 and the dielectric resonator 1 is irradiated with the light through the condenser lens 13. The dielectric resonator 1 is placed in the scanning area of the laser beam scanner 12, and the resonance frequency measuring device 14 can measure the resonance frequency at any time via the antenna measuring terminals 7 and 8. Further, the resonance frequency measuring device 14 is a computer 15
It is connected to the device, so that measurement data can be transferred or measurement parameters of the resonance frequency measuring device 14 can be set. Further, the computer 15 has software and data relating to an algorithm necessary for execution of trimming, performs various arithmetic processes on the trimming algorithm, and gives an instruction to the control unit 16. The control unit 16 is configured to control the laser oscillator 11 and the laser beam scanner 12, and mechanically control the supply and removal of the dielectric resonator 1.

Next, the trimming of the dielectric resonator 1 by the laser trimming device for adjusting the resonance frequency of the dielectric resonator of the present invention thus constructed will be described.

FIG. 3 is a perspective view of the dielectric resonator 1 as seen from the electrode open end side. The hatched portions in FIG. 3 indicate surface electrode portions, and double hatching therein. A part is a region to be laser-trimmed for adjusting the resonance frequency. Here, the coordinate axes x and y are taken as shown in FIG. 3, the laser beam 4 is an Nd-YAG laser oscillator 11 with an ultrasonic Q switch, and the laser beam scanner 12 scans a distance a in parallel with the y axis. Let Furthermore, a distance x approximately equal to the laser processing groove width
The laser beam 4 is scanned by moving it in the axial direction. By repeating this operation, the area trimming is executed until the dielectric resonator 1 reaches the desired resonance frequency in the double-hatched trimming area in FIG.

In this way, the area trimming of the surface electrode of the dielectric resonator 1 is performed by separating the laser beam 4 by substantially the same length as the width of the laser processing groove formed when the laser beam 4 is linearly scanned.
Is done by scanning in parallel. That is, the area trimming by the laser light 4 forms an area by integrating the linear trimming, and the area trimmed portion is formed by a large number of fine laser processed grooves.

However, since it takes a relatively long time of several hundred milliseconds to measure the resonance frequency, the area to be trimmed of each dielectric resonator 1 is accurately predicted in order to perform the trimming efficiently. An algorithm is required, and a highly accurate and practical trimming area prediction algorithm adopted in this embodiment will be described below.

First, before carrying out mass production trimming, it is necessary to experimentally obtain the relationship between the trimming area of the production lot to be trimmed and the change amount of the resonance frequency. In FIG. 4, for some dielectric resonators 1, the horizontal axis represents the length of the laser-trimmed region in the x-axis direction, and the vertical axis represents the change amount of the resonance frequency (= resonance frequency at that time-initial resonance frequency). Is illustrated. In FIG. 4, the alternate long and short dash line is the maximum frequency change curve, and the alternate long and two short dash line is the minimum frequency change curve. Here, in order to obtain a typical relationship between the trimming area and the resonance frequency, the curve with the maximum variation indicated by the alternate long and short dash line is adopted as a representative. Then, an nth-order algebraic function is obtained by performing a least squares approximation on such a curve using, for example, an orthogonal polynomial. In this embodiment, it is approximated by a quartic function. This is the reference frequency change curve Δ
Let f = f (x).

FIG. 5 shows a flowchart of this algorithm. First, the initial resonance frequency of the dielectric resonator 1 to be trimmed is measured, then the difference from the trimming target resonance frequency is produced, and the amount is set to Δf1. When trimming the resonance frequency, if the upper limit of the target frequency is exceeded, the product becomes defective and cannot be reproduced. Therefore, as the primary trimming, a trimming area is obtained so that the trimming is 80% of Δf1, and the laser light 4
To illuminate and trim the area. This is to obtain a value of x such that f (x) = Δf1 × 0.8 from the above equation and perform laser trimming to that position, and the value of x at this time is x1.

Next, the resonance frequency after the first trimming is measured to calculate the difference from the trimming target resonance frequency, and the amount is set to Δf2. An apparent target frequency is introduced here. This is defined by an apparent target frequency = (Δf1 × 0.8) + Δf2. Therefore, the second trimming is performed by obtaining the value of x, that is, x2 such that f (x) = (Δf1 × 0.8) + Δf2, from the above equation and trimming to that position.

Further, the resonance frequency after the second trimming is measured to check whether or not the trimming target frequency is within the conforming standard, and if the result of the check is less than or equal to the lower limit of the trimming target frequency, the second trimming is performed. Repeat the same operation as trimming. In addition, when the resonance frequency is within the standard of good product, it is a good product, and when it exceeds the upper limit of the good product standard, it is a defect.

When mass production of trimming is actually carried out using the algorithm configured as described above, basically, it is possible to obtain a good product by trimming almost twice, and the yield is at a sufficiently satisfactory level.

When the dielectric resonator 1 is irradiated with the laser beam 4 as in the present embodiment, the dielectric material vitrifies due to high temperature and loses its properties as a dielectric material, and the Q value representing the sharpness of resonance is lowered. There are challenges. However, in the grinding with a grindstone, the reduction of the Q value is at a level where practically no problem occurs. Therefore, when laser trimming is performed, it is necessary to find a method for reducing the Q value of the dielectric resonator 1 as much as possible. Therefore, the following series of experiments were conducted. First, a laser is used to perform rectangular area trimming, and the Q value is measured. Then, a grindstone is applied onto the laser-trimmed portion to grind the entire laser-trimmed area, and the Q value is measured. In this way, the Q value once deteriorated after laser trimming is almost restored to the original value after grinding.

Further, as shown in FIG. 6, there is an experimental fact that when one side of a rectangular region which is first laser-trimmed is grinded with a grindstone into a groove shape, the Q value is similarly recovered by itself. This suggests that the deterioration of the Q value can be suppressed by not deteriorating the dielectric around the one side forming the boundary of the trimming area.

Further, as shown in FIG. 7, the energy of the laser beam 4 is a function of the cosine of the incident angle θ, that is, cos θ, so that the energy when the laser beam 4 is irradiated from the tangential direction becomes the minimum. In the present invention, in order to obtain the same Q value deterioration preventing effect as in FIG. 6, laser trimming is started near the corner R of the dielectric resonator 1 as shown in FIG. As a result, by irradiating the laser beam 4 from the tangential direction at the trimming start point, the effect of suppressing the deterioration of the dielectric around one side of the trimming region due to the laser can be obtained, and the dielectric resonator 1 It is possible to minimize the decrease in Q value.

In this embodiment, the method of performing laser trimming at two places by using the two turntables 2 and 3 is adopted. The reason will be described below. FIG. 9 shows two trimming stations 5 and 6 for laser trimming.
2 is a timing chart of. According to the algorithm described above, the normal trimming is performed in two steps. Here, a timing chart when the trimming is performed twice to obtain a good product will be described. First, the trimming station 5 (A side) measures the resonance frequency. This is shown at 17 in FIG. Subsequently, the first laser trimming 18 is performed according to the algorithm. During this period, the resonance frequency is measured at the trimming station 6 (B side).
I do. Then, when the trimming 18 on the A side is completed, the resonance frequency measurement 20 is performed, and at the same time, the laser trims 21 on the B side.

Further, when the trimming 21 is completed, the resonance frequency measurement 22 is performed, and at the same time, the second trimming 23 is performed on the A side. Then, the resonance frequency measurement 24 is performed, and the turntable rotates by 90 degrees at the index 25. Immediately after the end of the trimming 23, the second trimming 26 on the B side is executed, and then the resonance frequency measurement 27 is performed to index the turntable on the B side by 90 degrees. This completes one cycle of laser trimming on the A side and B side.

As described above, the advantage of providing the two trimming stations on the A side and the B side is that when the laser trimming is performed as shown in the timing chart of FIG. 9, the resonance frequency is measured on the other side. That is what you can do. As a result, the measurement of the resonance frequency, which requires a relatively long time, is overlapped within the time for executing the laser trimming, and the pitch time required for trimming per piece can be significantly reduced.

In the present embodiment, the structure having a plurality of trimming stations has been described. However, even in the case of a single trimming station, laser processing is superior to grinding processing in high speed and high precision processing. It is possible to obtain a great effect which has never been achieved.

[0030]

As described above, the laser trimming device for adjusting the resonance frequency of the dielectric resonator according to the present invention uses a trimming amount predicting algorithm due to the abrasion of the grindstone, which has been a problem in the conventional grinding using the grindstone. It is possible to solve the problems of reduced accuracy, pitching of the dielectric resonator at the time of contact with the grindstone, and slow pitch time. It is possible. Further, the present invention provides a practical method capable of minimizing deterioration of the Q value of the dielectric resonator due to laser processing.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing a configuration of a laser trimming device for adjusting a resonance frequency of a dielectric resonator according to an embodiment of the present invention.

FIG. 2 is a block diagram of the same.

FIG. 3 is a perspective view of a dielectric resonator showing a laser trimming portion according to the same embodiment.

FIG. 4 is a characteristic diagram showing the relationship between the trimming area and the amount of change in resonance frequency according to the embodiment.

FIG. 5 is a flowchart showing a procedure of an algorithm for predicting a trimming area according to the same embodiment.

FIG. 6 is a perspective view showing a state in which one side of a boundary of a trimming region is ground by a grindstone according to the embodiment.

FIG. 7 is an explanatory view showing an incident angle of laser light according to the same embodiment.

FIG. 8 is a front view showing a laser trimming processing state according to the embodiment.

FIG. 9 is a timing chart of laser trimming according to the embodiment.

FIG. 10 is a perspective view of a main part showing a configuration of a conventional trimming device for adjusting a resonance frequency of a dielectric resonator.

[Explanation of symbols]

 1 Dielectric Resonator 2 First Turntable 3 Second Turntable 4 Laser Light 5,6 Trimming Station 7,8,9,10 Antenna Measuring Terminal 11 Nd-YAG Laser Oscillator with Ultrasonic Q Switch 12 Laser Beam Scanner 13 Condensing Lens 14 Resonance Frequency Measuring Device 15 Computer 16 Control Unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Nonaka 55-12, Ozumi, Osamu, Tanabe-cho, Tsuzuki-gun, Kyoto Prefecture Matsushita Nitto Electric Co., Ltd.

Claims (1)

[Claims] 1. A supply unit that supplies a dielectric resonator, a table unit that holds the supplied dielectric resonator and rotates intermittently, and a resonance frequency of the dielectric resonator that is held by the table unit is measured. A measuring unit and an arithmetic unit that determines the trimming amount of the dielectric resonator measured by the measuring unit based on an algorithm that predicts the trimming area of the dielectric resonator from the relationship between the trimming area and the resonance frequency change amount stored in advance. And a laser oscillator having an optical system for performing trimming by scanning the surface electrode of the dielectric resonator from a corner end to a position where a required area is obtained based on the result of the calculation unit, and a dielectric unit including a control unit for controlling these. Laser trimming device for adjusting resonance frequency of body resonator.