JPS59162440A - Material checking device - Google Patents

Abstract

PURPOSE:To check the outer configuration of a material accurately, by comparing the voltage which is obtained by dividing the voltage of an output signal of a light receiving element corresponding to the amount of received light, with a reference voltage based on said output voltage, and obtaining the detected signal, which varies with the amount of the received light. CONSTITUTION:Light beams are projected by lamps 1 and 1', and the quality of the outer configuration of a material observed from the two directions is checked. The light beam from the lamp 1 is received by a phototransistor 7 through an optical fiber 2, a semiconductor pellet 3, and the like, and inputted to an AMP11. An output signal Vout of the AMP11 is inversely proportional to the amount of the received light from the lamp 1. As the semiconductor pellet 3 is conveyed in the direction of A, the amount of the received light of the transistor 7 is gradually decreased, and the Vout is gradually increased. When the amount of the received light becomes 0, the voltage level becomes flat. In a voltage comparator 15, an output voltage Vout' of a dividing circuit 12 is compared with the output voltage Vout, which is a reference. Thus the quality of the outer configuration of the semiconductor pellet 3 can be determined.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an article inspection device that detects the outer shape of an article being transported and determines whether the outer shape of the article is good or bad. This is suitable for use when determining the quality of a product.

[Background technology]

According to the inventor's research prior to the present invention, the above-mentioned article inspection device is equipped with a light emitting element (for example, a lamp) and a light receiving element (for example, a phototransistor), and the article inspection device is provided with an article between the light emitting element and the light receiving element. A method is adopted in which the quality of the external shape of the article is inspected based on the transmission time of light and the like. However, studies by the present inventors have revealed that the above method cannot perform accurate inspection when the illuminance of the light emitting element changes or when dust or the like adheres to the light emitting element or the light receiving element.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an article inspection device that can perform reliable inspection operations even when there is a change in illuminance of a light emitting element or poor light transmission due to dust or the like.

[Summary of the invention]

A brief summary of the invention disclosed in this application is as follows.

In other words, the voltage obtained by dividing the output signal corresponding to the amount of light received by the light-receiving element is compared with the reference voltage based on the output signal, and the voltage is detected based on the time width of the divided voltage that changes in accordance with the amount of light received. The signal is used to accurately inspect the external shape of the article.

〔Example〕

Hereinafter, an embodiment of an article inspection apparatus to which the present invention is applied will be described with reference to FIGS. 1 to 4.

FIG. 1 shows the overall circuit configuration of the article $A-f device. The lamp 1 is used as a light-emitting lamp and is lit by a DC power supply (2). 2 is an optical fiber;
It is used to conduct the light generated from the lamp 1 without diffusing it.

3 is a semiconductor pellet, which is sucked and held by a vacuum suction collet 4.

Regarding the conveyance path of the semiconductor pellet 3, etc.,
This will be described later with reference to FIGS. 2 and 3.

5 is a magnifying lens, and its magnification may be about 10 times. Further, 6 is a Nislit, which is for blocking unnecessary light. 7 is a phototransistor used as a light receiving element, and is for receiving light generated from the lamp 1.

Here, the transport direction and the luff of the semiconductor pellet 3.

The positional relationship with the light emitted from 1 will be described.

Semiconductor pellets) are transported in the direction of arrow A shown in FIG. In reality, measurement light is applied to the semiconductor pellet 3 from two directions indicated by arrows a and b.

The light L and L' emitted from the lamps 1 and 1' will be irradiated and the quality of the external shape viewed from two directions will be calibrated.Therefore, two inspection devices each having a phototransistor 7 are provided. The circuit configuration and operation of both circuits are the same. Therefore, below, the circuit operation when receiving light in the direction of the arrow will be described.

The positional relationship between the light and the semiconductor pellet 3 in the direction of the arrow can be expressed as shown in FIG. That is, the position it t + shown in FIG. 2 is as shown in FIG. 3.
, r, and similarly below, 1t & t, l, t3 is
, 1, t4 is such that the semiconductor pellet 3 corresponding to 1 is at position 1. At this point, all of the measurement light is received by the phototransistor 7. At this time, the output signal V of the amplifier 11. The output signal V of the amplifier 11 will be at a low level (L level) as shown in the period from ut&s4 to 1. The voltage level of ut is made to be inversely proportional to the amount of measurement light received.

Next, as the semiconductor pellet 3 is transported in the direction of arrow A, the amount of light received by the phototransistor 7 gradually decreases, and the output signal V is generated. The voltage level of ut is as shown in Figure 4.
, r to t2''. Then, t2'
t31, the phototransistor 7 is completely blocked from receiving the measurement light, so the output signal V. u
The voltage level of t also becomes flat. Since the semiconductor pellet 3 is continuously conveyed in the direction indicated by the arrow, it moves from tJ to t and l. Then, from t31 to 1,
The amount of light received by phototransistor 7 gradually increases. As a result, the voltage level of the output tank @vout of the amplifier 11 is
It gradually decreases as shown between t3'' and t4' in FIG. 4(4).

The output signal V is supplied to the divider circuit 12 and the holding circuit 13. The wax divider circuit 1'2 is constituted by a variable resistor 2, and the output signal V is supplied to the divider circuit 12 and the holding circuit 13. ut to the desired voltage level■. ut
' and supply it to the voltage ratio axis 1lv1150 input terminal. Therefore, output No. 16 ■. The waveform of ut゛ is the output signal ■. It changes in the same way as ut, and the voltage level is lowered.

Holding port 1! ? Reference numeral 513 denotes a time constant circuit composed of a resistor R1 and a capacitor C1, and its time constant is made sufficiently larger than the conveyance speed of the processed semiconductor pellet 3. Therefore, the output voltage of the holding circuit 13 is ■.

is the output voltage V which will result in a voltage signal with less deterioration in voltage level as shown in FIG. 4 FCI. & voltage comparison circuit 15
is supplied to the negative phase input terminal (-) of the voltage comparison circuit 16 and the positive phase input terminal (+) of the voltage comparison circuit 16.

The voltage comparison circuit 15 outputs a voltage V. 0) Voltage level V
A voltage comparison circuit compares the output signal vou,' of the dividing circuit 12 with I as a reference. Then, while the voltage level of the output (N V. A detection signal V8 indicating 0° is obtained.The time filliilT of the detection signal Vs is proportional to the width W of the semiconductor pellet 30 in the diagonal direction, so the quality of the external shape of the semiconductor pellet 3 can be determined from the time width T.

If the outer shape of #5# body-pent 3 is damaged as shown by the imaginary line in Fig. 3, the time width between t: and tz shown in Fig. 4 (4) will become narrower. The time width between t,' and 1 is also narrow. Then, the time width T of the detection signal 8 becomes narrower, and it is determined that the semiconductor substrate 3 has a defective outer shape based on the time difference from the normal time.

By the way, in the above-described inspection apparatus, if dust or the like adheres to the lamp l or the surface of the phototransistor 70, the amount of light received by the phototransistor 7 will decrease. In this case, the output signal ■. Since the voltage level of ut will increase overall, the output voltage v of the dividing circuit 12
', further holding surface ut i! The voltage level V1 of the output voltage V0 of No. 13 also increases at a similar rate. As a result, the voltage comparator circuit 15 obtains the detection signal 8 similar to the above.

Further, the above circuit operation is performed in the same way when the illuminance decreases due to deterioration of the lamp 1 or the like. Therefore, the inspection device will not malfunction due to the above-mentioned adhesion of dust or deterioration of the lamp 1. On the other hand, if the lamp 1 is disconnected,
If the phototransistor 7 is damaged, the input signal based on the measurement light will not be supplied to the amplifier 11 at all. This is an obvious failure, but when a failure occurs, the abnormality is detected by the circuit operation as described below.When the above-mentioned v-mouth failure occurs, the output signal ■. The voltage level of ul continues to be at a high voltage level as shown between t: and 1 of the fourth mode. Therefore, the output voltage vout',
The voltage level of o also becomes the output voltage. V engineer,
For abnormality detection (7Q'* The voltage is compared with the output voltage VF of the abnormal value setting circuit 17 by the pressure comparison circuit 16.
The above output voltage V is connected to the reference voltage V using a variable resistor VR.
, the voltage level may be a voltage value determined in advance through experiments or the like.

And the output voltage ■ is higher than the output voltage ■2. When the voltage level rises and the voltage becomes low, a high level i (H level) abnormality detection signal 1 is obtained from the voltage comparator circuit 16.

Based on this abnormality detection signal ■, the occurrence of a failure is notified.

Various methods may be used for the notification, such as turning on a warning lamp or generating a warning sound.

〔effect〕

(1) Obtain the voltage divided by 5 from the output signal corresponding to the outer shape of the article and the reference voltage, and compare the two to detect the outer shape of the article. Even if a level change occurs in the above output signal, the 1-part voltage and the reference voltage change relative to each other, which makes it possible to measure the external shape of the article while compensating for changes in illuminance, etc. It will be done.

(2) By providing a comparison circuit between an independent reference voltage and a reference voltage obtained from the output signal, it is possible to obtain the effect of detecting an abnormality when the output signal changes abnormally.

According to fl) t21, it is possible to continue the outer shape inspection of the article while performing the illuminance correction, and also to detect abnormalities, so that a synergistic effect of improving the efficiency of inspecting the outer shape of the article can be obtained.

What are the inventions made by the inventor? Although the present invention has been specifically explained based on the embodiments, the present invention is not limited to the above embodiments, and can be modified in various ways without departing from the gist thereof.

That is, the light source is not limited to a T-type lamp, but any light emitting element such as a light emitting diode may be used. Further, the light receiving element is not limited to a phototransistor, and other Marugame elements can also be used.

Next is the output signal■. ut' and reference voltage■. The comparison with the output signal (■) obtained from the amplifier 11 is made using analog quantities as is. Alternatively, the detection signal and abnormality detection signal may be obtained by digital comparison.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to the external shape inspection of bovine conductor pellets, which is the background field of application, but the present invention is not limited to this. As long as it is an external shape inspection of a certain article, it does not matter what kind of article is being inspected.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of an article inspection device to which the present invention is applied. FIG. 2 is a plan view of the main parts showing the relationship between the movement status of the article and the measurement light. FIG. 3 is an enlarged plan view of the main parts of the same as above. FIG. 4(4)(C)0 is a waveform diagram for explaining the circuit operation of the article inspection device. DESCRIPTION OF SYMBOLS 1... Lamp, 3... Semiconductor pellet, 7... Photo transistor, 12... Division circuit, 13...
Deep circuit, 15.16... Voltage comparison circuit, Vs...
Detection signal, vX... Abnormality detection signal, L... Measurement light. Figure/7 Figure 2 Figure 3

Claims (1)

[Claims] 1. Measurement tv in which the amount of transmitted light changes as the article moves
A light receiving element for receiving light, a dividing circuit that divides the voltage of an output signal corresponding to the amount of received light obtained from the light receiving element, a holding circuit that holds the reference signal obtained from the output signal at a predetermined voltage level, and a reference signal obtained from the above output signal. An article inspection device comprising: a voltage comparison circuit that compares the output signals of the divided circuits;