JP2000269764A - Method and device for inspection of quartz vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically perform efficient inspection in a short time without increasing the number of substantial inspectors by measuring electrical feature and classifying it, on the basis of measurement data after individually detecting faults of an outward appearance optically. SOLUTION: A quartz piece 1 is irradiated with a light from a light source 4, which is a transmission light of an outward appearance inspection stage 3 of a transparent glass, its outline, a boundary between a bevel surface and a planar surface, a state of etching unevenness, a fault position and shape, and a size are focused upon a CCD camera 5 by a luminance difference, a light amount of a pixel is scanned, a dimensional accuracy of the quartz piece 1 and the fault of the outward appearance are stored in a controller 100. After that, the quartz piece 1 is dropped to an electrical feature detection stage 7 by a rocking lever 6, an oscillation frequency and an equivalent resistance value at the time of serial resonance are measured by a movable electrode 7b on a fixed electrode 7a, and their data are stored in the controller 100. Then, the quartz piece 1 is picked up by a rocking lever 8 and classified into one section in a classifying device 9, according to two data stored by the controller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for inspecting a quartz oscillator. More specifically, the present invention relates to an inspection method and an inspection apparatus in which a heterogeneous inspection of a crystal piece, which is a main component constituting the crystal oscillator, is combined among various inspections performed until the crystal oscillator is completed.

[0002]

2. Description of the Related Art Quartz resonators go through a number of inspection steps until they are completed. Although the items of each inspection are various, it is basically aimed at obtaining satisfactory electric characteristics as an electronic circuit element. The main electrical characteristics are oscillation frequency (F), CI (equivalent resistance value at series resonance), spurious frequency, temperature characteristic of frequency, temperature characteristic of CI, oscillation start voltage, and excitation power dependency of CI (drive level). dependenc
e; referred to as DLD characteristics), and a quartz oscillator that requires high performance is required to satisfy all of these characteristics.

Although it is not impossible in principle to directly measure these electrical characteristics, some items require extremely long time for measurement. For example, frequency or CI
It is extremely troublesome to measure the temperature characteristics while applying a temperature change so that the temperature of the sample in the thermostat is not uneven. The work (DLD characteristic) of measuring while changing the drive level (excitation power) is not as good as the temperature characteristic, but requires a lot of time due to many repeated measurements. After all, it is extremely difficult in terms of man-hours and facilities to inspect all the main characteristics of the crystal resonator mass-produced by 100% inspection instead of sampling. However, some inspection items can be inspected in a state of a crystal piece (a vibrating body not yet mounted on the terminal in the container), which is a main component thereof, without being in a state of a sealed completed vibrator.

FIG. 4 is a flowchart of a conventional example showing a general manufacturing process of an AT plate quartz resonator. Each process is A,
Symbols are attached to the three groups B and C, but the group B is a group of steps that are changed in the embodiment of the present invention described later, the group A is a preceding step group, and the group C is a subsequent step. Group.
First, in step A1, a quartz wafer is cut out from an artificial quartz rough at a predetermined cut angle, and the wafer is subjected to rough polishing by lapping in step A2 and finish polishing in step A3.
In step A4, the wafer is further cut vertically and horizontally to form a plurality of individual rectangular plate-shaped crystal pieces. In steps A5 and A6, beveling is performed as necessary depending on whether there is a request regarding the frequency band and the size of the crystal unit.

[0005] After the above-described process, the crystal blank becomes a lot of tens of thousands. In step B1, a small number of samples are extracted from one lot, and visual inspection is performed to determine whether the processing has been performed normally. If there is a defect, the lot becomes defective. Here, the description of the manufacturing process is interrupted, and a description relating to a main shape defect is inserted.

FIG. 5 is a view showing an example of a main defective appearance of a crystal blank. Reference numeral 1 denotes a rectangular plate-shaped crystal piece. (A) is the case where the width of the bevel surface 1a is different in one side in the rectangular plate crystal piece with a bevel, (b) is when the bevel surface is inclined, and (c) is when the plate surface is wrapped. (D) is a case where the plate surface or edge has a crack 1c or a chip 1d. After the electrode film 1e is formed by vapor deposition on the plate surface, defects such as scratches on the plate surface often become inconspicuous and cannot be visually inspected. (E),
When the quartz pieces are in close contact with each other in the etching solution as in (f), the etching does not proceed at the contact portion, and uneven etching occurs. This is also a microscopic appearance defect. In any case, the frequency or CI may deviate from the design value, or the influence of spurious vibration may appear.

Returning to the description of the manufacturing process of FIG. If the lot passes, the frequency (F) and CI are measured and checked one by one at room temperature in step B2. Since no electrode is attached to the quartz plate yet, excitation is performed using a so-called air gap method in which a sample quartz piece is placed on a fixed lower electrode and held over an upper electrode. Also, when measuring both F and CI, the electrical response (insertion impedance) of the crystal blank is measured while sweeping the frequency using a network analyzer. The frequency is measured. When both F and CI are measured, for example, about 2 seconds are required for one measurement, but measurement of only F can be performed in 1 second. Defective products are removed, and non-defective products are etched in step B3.

[0008] The crystal blank after the etching step B3 is again inspected for F and CI in step B4. Then, the defective product (which may include the above-mentioned uneven etching) is removed as a defective product, and the non-defective product is transferred to the next step. After being sufficiently cleaned in the next step C1, an electrode film is formed by vacuum deposition in a step C2. Next, in step C3, a frequency check is performed on the quartz piece attached with the electrode, and rejected products are removed. Passed products are assembled (mounting on a container base) C4, frequency adjusting process (trimming by laser). C5, hermetic sealing process C6
Is completed as a quartz oscillator. The completed crystal unit is further subjected to various characteristic tests as required (whole or sampling tests, such as F,
The non-defective product is shipped (C8 process).

[0009]

The conventional inspection method has the following problems. (1) Cracks, scratches, dimensional defects, bevel shape defects, uneven etching, etc. of the crystal piece cannot be sufficiently detected by the sampling inspection, and the defective product flows out and mixes in the subsequent process. Therefore, a latent defective product is value-added to the final process uselessly.
It is not possible to perform advanced quality control to keep the rate at a low rate of several hundred thousand parts. Even if a visual inspection of all the appearance defects is performed, the efficiency is extremely low, and the inspection results vary from individual to individual, so that high reliability cannot be obtained.

(2) No correlation information between the appearance defect factor and the crystal oscillator characteristics can be obtained at all. Therefore, even if there is a defect in the crystal resonator characteristics, it is not known what kind of defect occurred in the previous process. If there is such correlation information, it will be useful information for performing extremely high quality control as described in the previous section. (3) Since poor appearance is the imperfect shape of the crystal piece,
Depending on the situation and degree, change the frequency of the secondary vibration,
Therefore, it is conceivable that the influence of the coupling state between the main vibration and the sub-vibration may cause a jump in frequency due to DLD characteristics or temperature or an abnormal CI. Therefore, if the appearance defect is carefully examined, it may be possible to use it as a substitute characteristic in place of the above-mentioned various characteristics in which the total inspection is difficult. Heretofore, no attempt has been made to sufficiently utilize the visual inspection from such a viewpoint.

In connection with the above problems (1), (2) and (3), the following preliminary experiments were conducted. The appearance inspection of the crystal vibrator (quartz piece) with the electrodes peeled off was performed again for hundreds of crystal resonators that were determined to have a CI defect, and most of the crystal pieces were chipped or scratched, and the position was rectangular. It turned out that it concentrated on the area | region near the long side of a board, or the edge (ridge) of a long side. In the beveled or convex processed quartz pieces, the defect positions were concentrated in the center of the long side (the length was about half of the long side). This is a fact that clearly indicates that there is a strong correlation between poor appearance and electrical characteristics.

A quartz oscillator is an element that exhibits its mechanical vibration characteristics as electrical characteristics through a piezoelectric phenomenon. Therefore, a change in the shape of the crystal blank always appears as a change in its electrical characteristics. When the frequency of the main vibration to be used is high, such as an AT plate (thickness shear resonator), which is a typical example of a crystal resonator,
Some higher-order modes of various contour vibrations always occur near the frequency of the main vibration. Since the frequency of these sub-vibrations changes greatly with temperature, when the sub-vibration is coupled with the main vibration at a certain temperature, the adverse effect of jumping the frequency of the main vibration or rapidly increasing the CI value is likely to occur.

When designing the crystal blank, the dimensions of each side of the crystal blank are set so that the frequency of the higher-order contour vibration is as far away from the main vibration frequency as possible. The frequency of the contour vibration changes from the design value, becomes very close to or coincides with the frequency of the main vibration, and different types of vibrations combine to impair the characteristics of the main vibration. I can imagine what would happen. Since the coupling of vibration is a non-linear phenomenon, a defect in appearance may also be a major cause of CI abnormalities (hysteresis phenomenon, etc.) or oscillation failure due to drive level, for which the cause has not been sufficiently grasped conventionally. . That is, if the appearance defect of the crystal blank can be detected at a sufficiently high level, it is considered that even if the characteristic is difficult to perform the total inspection, the potential defect may be drastically reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inspection method and an inspection apparatus which can be used in the manufacturing process of a quartz oscillator which can reduce the number of potential defective products remaining in the conventional inspection method and which is efficient. is there. Another object of the present invention is to provide an inspection method and an inspection apparatus capable of obtaining correlation information between external appearance failure factors and crystal resonator characteristics and enabling higher-level quality control in a high-precision crystal resonator. It is to be. Still another object of the present invention is to provide an inspection method and an inspection apparatus capable of performing a more advanced quality control of a crystal unit by measuring a cut angle of a crystal piece together with an appearance element in an inspection process. It is to provide.

[0015]

To achieve the above object, the inspection method of the present invention has the following features. (1) A step of inspecting a crystal blank having no electrodes formed thereon, wherein the first inspection step of optically individually detecting the presence of a defect on the appearance of each crystal blank and an electrical test including the same crystal blank frequency And a second inspection step of measuring a characteristic characteristic, and classifying the quartz pieces passing through both steps based on at least the measurement data in the first inspection step and the measurement data in the second inspection step. thing.

The inspection method of the present invention may further include at least one of the following features. (2) The first inspection step precedes the second inspection step.

(3) Before the first inspection step, there is provided an alignment supply step in which a large number of quartz pieces are aligned and sequentially supplied, and the main part of the alignment supply step is at least in an atmosphere where the humidity is controlled. To be placed in

(4) Further ions are added to the atmosphere.

(5) In addition to the first inspection step and the second inspection step, the method includes a third inspection step of measuring a cut angle of each of the quartz pieces, and passes the three inspection steps. Quartz blanks shall be classified according to the type and degree of appearance defects, cut angle, and electrical characteristics.

The inspection apparatus of the present invention has the following features. (6) A first inspection stage having supply means for aligning and sequentially sending out a large number of crystal blanks on which electrodes are not formed and optical means for individually detecting the presence of defects on the appearance of the crystal blanks. A second inspection stage having electrical measurement means for measuring the frequency or electrical characteristics of the crystal blank, and classification means for classifying the crystal blank that has passed through both of the inspection stages based on at least the inspection data at both stages; That you have.

The inspection apparatus of the present invention may further have at least one of the following features. (7) The first inspection stage is provided before the second inspection stage.

(8) A main part of the supply means is covered with a cover, and a control means for controlling at least humidity of an atmosphere inside the cover is provided.

(9) An ion generating means for making the atmosphere inside the cover conductive is further provided.

(10) In addition to the first inspection stage and the second inspection stage, a third inspection stage for measuring the cut angles of the individual crystal blanks is included, and passes through the three inspection stages. Quartz blanks shall be classified according to the type and degree of appearance defects, cut angle, and electrical characteristics.

[0025]

FIG. 3 is a flow chart of a process for manufacturing a crystal unit including an inspection method according to a first embodiment of the present invention. The steps of the group B have a portion different from the manufacturing process of the conventional example of FIG. 4 described above, and the changed steps are denoted by new symbols. The description of the processes belonging to the groups A and C is omitted. The crystal pieces that have been beveled as required in the previous step are subjected to a visual inspection and an F / CI inspection by sampling in step B5 for all the pieces, and pass / fail of the lot is determined. In addition, this process enclosed by the dotted line
It can be omitted if there is little possibility of lot failure. The goods of the passed lot are etched in the B3 process,
In step 6, the appearance inspection and the F and CI inspections are performed on all the parts (in step B6, one is shown on the chart, but in reality, the inspection is divided into two steps of the appearance inspection and the F and CI inspections).
The individual crystal blanks were evaluated as good or bad according to the appearance data and F / CI data written for each of them.
They are also classified according to their contents. As described above, the amount of quality information relating to individual materials increases, so that a high level of quality control becomes possible. The non-defective product proceeds to the next process of the group C.

FIG. 1 is a schematic view showing an inspection apparatus according to a first embodiment of the present invention, which is an apparatus for executing the step B6 in FIG. 3, wherein (a) is a schematic plan view and (b). Is a schematic partial side view. In both figures (a) and (b), reference numeral 2 denotes a well-known alignment supply device, which has a mortar shape, has a helical ramp on a slope, and a large number of crystal pieces (not shown) at the bottom.
Has been turned on. Vibration is applied to the alignment supply device 2, and the crystal blank 1 climbs the ramp and reaches the alignment gate 2a at the upper end, and only the one in the correct orientation passes through the alignment gate 2a,
It is sequentially pushed out to a predetermined position on the visual inspection stage 3 in a correct direction (a mechanism for pushing out in a parallel movement is not shown).

The appearance inspection stage 3 includes a transparent glass table,
It comprises a light source 4 arranged at the lower part and a CCD camera 5 arranged at the upper part (the light source 4 and the CCD camera 5 are not shown in (a)). Since the crystal blank 1 is illuminated with transmitted light, the contour of the image plane of the CCD camera 5, the boundary between the bevel plane and the plane, the state of uneven etching, the position of the defect and its shape, and the difference in brightness are different from each other. An image is clearly formed, the amount of light of the pixel is scanned, the information is output as defect information on the dimensional accuracy and appearance of each part of the crystal blank, and stored in the control device 100 as appearance inspection data. Usually, the retention time of the crystal piece in this inspection stage may be about 1 second.

The crystal blank 1 which has completed the appearance inspection as the first inspection step is picked up and moved by the swing lever 6 which has a vacuum suction device at the tip and reciprocates between two stages, and moves to the second stage. It is dropped on an electrical characteristic inspection stage 7 which is an inspection process. The electric characteristic inspection stage 7 is a small mortar-shaped base, having a disk-shaped fixed electrode 7a at the center bottom and a disk-shaped movable electrode 7b at the top, and both electrodes are connected to a network analyzer 7c. The crystal blank 1 dropped from the top slides on the slope and settles on the fixed electrode 7a. During this time, the movable electrode 7b that has escaped to the upper dotted line position comes down, stops at a predetermined small gap from the upper surface of the crystal blank 1, and starts electrical measurement.

The electrical characteristics to be tested are usually the frequencies F and CI (it is not impossible to determine other equivalent circuit constants). The time required to determine both characteristics is about 2
Seconds. If only the frequency is acceptable, an oscillator can be connected to 7c in place of the network analyzer, and measurement can be performed in about half a second. The measurement data is stored in the control device 100
Send to memorize. When the measurement is completed, the movable electrode 7b is retracted again, and the swinging lever 8 with a suction function takes out the crystal blank 1 on the electrical characteristic inspection stage 7 and is a classifying device which is a dish-shaped container divided into a number of partitions. Drop it in one of the nine compartments.

The control device 100 operates according to the stored shape inspection data and electrical characteristic inspection data of the crystal blank.
The rotation angle of the classification device 9 is controlled so that the crystal blank 1 falls into a predetermined section. For example, the type, position, and degree of appearance defects are classified into several types, F and CI are set in several stages for each classification, and the items are combined.
The classification device 9 is provided with compartments divided into several tens to hundreds of stages in total, and can be classified finely.

Reference numeral 10 denotes a cover or enclosure for covering at least the crystal piece storage portion of the alignment supply device 2. Of course, the exit of the crystal blank 1 is open. The cover is connected to a humidifier 11 that can control the humidity of the internal atmosphere and an ionization device 12 that supplies ions to the internal air to impart conductivity. This is because the crystal blank is extremely small and lightweight,
This is to avoid a phenomenon that the static electricity sticks to each other (inspection and measurement become impossible). Empirically, when the humidity is reduced to 50% or less, the quartz pieces tend to adsorb to each other. The atmosphere is made conductive in order to quickly remove the generated static electricity.

FIG. 2 is a schematic side view showing a part of an inspection apparatus according to a second embodiment of the present invention, which is different from the first embodiment, that is, an inserted new inspection stage. And only the front and rear measurement stage positions for illustrating the insertion position. Reference numeral 13 denotes an inserted cut angle inspection stage, which forms an extension of the appearance inspection stage 3. The crystal blank 1 having undergone the appearance inspection slides to a predetermined position while maintaining its orientation, and stands still (parallel). The moving mechanism is not shown because it is not difficult).

The cut angle inspection stage includes an X-ray source 14 for applying an X-ray beam to a crystal blank from a predetermined angle, and an X-ray detector for receiving the X-rays reflected by the crystal lattice and accurately measuring the azimuth of the reflection angle. 15 are provided. In order for the X-ray beam to be reflected in a substantially predetermined direction, it is necessary that the orientation of the sides of the rectangular plate-shaped crystal piece is correct and that the crystal axis (X axis) of the crystal material is in the predetermined direction. . The orientation of the former side is almost aligned by the alignment gate of the alignment supply device 2, and a frame member (not shown) or the like is provided on the cut angle inspection stage 13 to guide the crystal blank 1 to be accommodated. Can be achieved.

Also, the direction of the crystal axis of the crystal pieces supplied in an aligned manner is such that the opposite direction is mixed with a half probability. If the reflected beam is not captured by the first X-ray irradiation because the crystal axis (X axis) is opposite, the turntable 13a provided with the cut angle inspection stage 13 and the crystal piece placed thereon is mounted on the stage. The reflected beam can be captured by rotating it 180 ° around the vertical axis by the reversing motor 13c provided below and irradiating it again with X-rays. The reversing motor 13c also has a suction function, and the plurality of suction holes 13b provided in the turntable 13a suck the crystal blank 1 onto the reference surface of the turntable 13a to prevent the crystal blank from shifting during measurement. I have.

The measurement of the cut angle can be performed in a sufficiently short time even if the reversing operation of the quartz piece is performed, and the cut angle is measured simultaneously with the other stages, so that the inspection time of the quartz piece does not increase. The inspection result is sent to the control device 100 (not shown).
And is used for controlling the classification device 9. This stage also requires an X-ray shield for safety, but is not shown. The crystal blank 1 after this measurement is moved to the next electrical characteristic inspection stage 7 by the swing lever 6, and the following behavior is the same as that of the first embodiment.

The permissible error of the cut angle required for a high-precision AT plate crystal resonator is, for example, about 10 seconds or more on one side, but an angle error close to this is generated even if the surface of the crystal wafer is lapped by lapping. Therefore, it is significant that all cut angles are inspected and added to the selection items. In the cut angle inspection, it is necessary to place the crystal blank 1 at the measurement position in a predetermined direction and orientation. However, as shown in this example, the crystal blank 1 is placed immediately after the appearance inspection stage and the material is moved in parallel. There is a merit that the cut angle can be measured without disturbing the azimuth aligned. Conversely, a cut angle inspection stage may be placed immediately after the aligning and feeding device 2, and then a visual inspection stage may be placed.

Although the embodiment of the present invention has been described above, the inspection items relating to the appearance, the range of the electrical characteristics, the combination thereof in the classification, and the configuration of the apparatus and the like are not limited to the above-mentioned specific examples, and various changes are made. Is of course possible within the technical scope of the present invention. For example, a configuration may be adopted in which when a defective product regarding the appearance appears, it is immediately classified as a defective product without moving to the electrical characteristic inspection stage.
Further, the structure of the alignment supply device is not limited to the illustrated example.

[0038]

According to the inspection method and the inspection apparatus of the present invention, all the optical appearance inspections are performed in series with the electrical characteristic inspection, so that the following effects are obtained. (1) As described above, the time required for the visual inspection is almost equal to or shorter than the time required for the electrical characteristic inspection. Therefore, even if the visual inspection step is added to all the crystal blanks, the tact corresponding to the electric characteristic inspection (for example, 2 for F and CI measurements
Second and 1 second for F only inspection). Therefore, there is no substantial increase in the number of inspection steps, and the inspection automatically and extremely efficiently proceeds.

(2) Since the appearance inspection is performed on all the crystal pieces, the appearance defects are thoroughly removed. (As described above, the appearance defects and the temperature characteristic abnormality and the drive level abnormality have a considerably strong correlation. It is believed that a considerable percentage of potential rejects for properties that cannot be 100% tested can be removed in advance, which can significantly increase product reliability.

(3) In addition, since inspection data on a large number of appearance defects can be obtained, detailed information on each item of the crystal blank processing in the previous process can be obtained and fed back to execute a high quality control.

(4) By classifying products by combining appearance inspection data and electrical characteristic data, products can be easily ranked according to required quality (accuracy), and the characteristics of the combined product can be reduced. By further pursuing, it has become possible to easily obtain a large amount of important quality information which has been difficult to obtain conventionally, such as what kind of appearance abnormality corresponds to how much characteristic change.

(5) By performing the entire number of appearance inspection processes on the crystal blank at the stage where the electrodes are not formed, the appearance failure data can be detected sharply (items which are difficult or impossible to detect after the electrodes are formed). is there).

(6) It is desirable to position the crystal blank on the stage for optical inspection of the appearance. However, the appearance inspection stage is arranged immediately after the aligning and feeding device, and then the electric characteristic inspection stage is arranged. This requirement can be met without any particular difficulty.

(7) By further adding a cut angle inspection stage, the variation in the temperature characteristics of the product can be further suppressed.
It is easier to sort high-precision products, and the reliability of the temperature characteristics of the products can be improved.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic diagrams showing an inspection apparatus according to a first embodiment of the present invention, in which FIG. 1A is a schematic partial plan view, and FIG. 1B is a schematic partial sectional view.

FIG. 2 is a schematic side view showing a part of an inspection apparatus according to a second embodiment of the present invention.

FIG. 3 is a flowchart of a crystal resonator manufacturing process including an inspection method according to the first embodiment of the present invention.

FIG. 4 is a flowchart of a crystal resonator manufacturing process including a conventional inspection method.

FIG. 5 (a), (b), (c), (d), (e),
(F) is a figure which illustrated the main appearance defect of the crystal piece, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz piece 1a Bevel surface 1b Lap flaw 1c Crack 1d chipping 1e Electrode film 2 Alignment supply device 2a Alignment gate 3 Visual inspection stage 4 Light source 5 CCD camera 6 Swing lever 7 Electrical characteristic measurement stage 7a Fixed electrode 7b Movable electrode 7c Network Analyzer 8 Swing lever 9 Classifier 10 Cover 11 Humidifier 12 Ionizer 13 Cut angle measurement stage 13a Turntable 13b Suction hole 13c Inversion motor 14 X-ray source 15 X-ray detector 100 Controller

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yusuke Iwahashi 4107 Miyoshida, Miyoshida-cho, Kitasaku-gun, Nagano Pref. 5 Inside Miyota Co., Ltd. (72) Inventor Katsunori Yanagisawa 4107 Miyoshida, Miyoshida-cho, Kitasaku-gun, Nagano Pref. 5 Miyota Co., Ltd. F-term (reference) 5J108 MM11

Claims (10)

[Claims] A first inspection step of optically individually detecting the presence of a defect on the appearance of each of the crystal blanks, wherein the frequency of the same crystal blank is determined. Including a second inspection step of measuring electrical characteristics including the quartz crystal blank that has passed through both steps based on at least the measurement data in the first inspection step and the measurement data in the second inspection step. An inspection method of a quartz oscillator characterized by being classified. 2. The quartz crystal resonator inspection method according to claim 1, wherein the first inspection step precedes a second inspection step. 3. An alignment supply step of aligning and sequentially supplying a large number of quartz pieces before the first inspection step,
3. A main part of the alignment supply step is placed in an atmosphere in which humidity is controlled at least.
Inspection method of crystal oscillator. 4. The method according to claim 3, wherein ions are further added to the atmosphere. 5. A third step of measuring a cut angle of each of the quartz pieces in addition to the first inspection step and the second inspection step.
5. The quartz pieces which have passed through the three kinds of inspection steps are classified according to the type and degree of appearance defects, cut angles, and values of electrical characteristics. Inspection method of any one of the crystal units. 6. A first inspection stage having supply means for arranging and sequentially sending out a large number of crystal blanks on which electrodes are not formed, and optical means for individually detecting the presence of defects on the appearance of the crystal blanks. A second inspection stage having electrical measurement means for measuring the frequency or electrical characteristics of the same crystal blank,
A crystal unit that classifies a crystal piece that has passed through both of the inspection stages based on at least inspection data from both of the stages. 7. The quartz crystal resonator inspection apparatus according to claim 6, wherein the first inspection stage is provided before the second inspection stage. 8. A supply device according to claim 6, wherein a main part of said supply means is covered with a cover, and a control means for controlling at least humidity of an atmosphere inside said cover is provided.
Inspection equipment for crystal units. 9. The inspection apparatus for a quartz oscillator according to claim 8, further comprising ion generating means for making the atmosphere inside the cover conductive. 10. A third inspection stage for measuring a cut angle of each of the quartz pieces in addition to the first inspection stage and the second inspection stage, wherein the third inspection stage has passed the three inspection stages. 10. The crystal resonator inspection apparatus according to claim 6, wherein the quartz pieces are classified according to the type and degree of appearance defects, cut angles, and values of electrical characteristics.