JPS59196535A - Method of determining quality of tubular bulb - Google Patents

Abstract

PURPOSE:To improve the reliability of quality determination by geneating a defective product signal only when the electric signal level caused by the transparent light from a bulb exceeds the integrated signal level. CONSTITUTION:A projection light source 2 illuminates the bulb surface of a fluorescent lamp 1 and transparent light is detected by a photoelectric conversion camera 3 by circumferentially rotating the bulb. The optical signal of a dark and shade picture on the bulb surface condensed by a lens is focused on an internal photoelectric conversion element and each photoelectric conversion element generates the electric signal in proportion to the dark and shade picture. The electric signal is directly input to a comparator 6 and is converted into an integrated signal by an integrated circuit 5 through an amplifier circuit 4 and then is input to the comparator 6. The comparator 6 compares the electric signal with the integrated signal. When there is a defect on the bulb surface, since the electric signal level of the photoelectric conversion camera 3 instantaneously exceeds the integrated signal level of the integrated circuit 5, a defective device signal is generated from a logic memory circuit 7 in this case.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 2゜The present invention relates to a method for determining the quality of a tube, and more specifically, to a method for determining whether the appearance of a tube is good or bad by inspecting the valve surface condition of the tube. It is something.

Conventional structure and its problems Conventionally, the appearance quality of tubes such as fluorescent lamps has been determined by visual inspection with the naked eye, which has disadvantages such as poor inspection efficiency and poor reliability of quality determination. there were. In order to eliminate such drawbacks, Japanese Unexamined Patent Publication No. 57
As shown in Japanese Patent No. 9034, etc., a management surface inspection device using a photoelectric conversion camera has been proposed. That is, in this device, a photoelectric conversion camera and a bulb are arranged so that the optical axis of the camera and the axis of the bulb are perpendicular, and a flood light source is provided outside the area connecting the camera and the bulb. The surface is irradiated and the reflected light from the bulb surface is detected by a photoelectric conversion camera. The bright and dark optical signals on the bulb surface focused by the lens are imaged by internal photoelectric conversion elements, and each element generates an electric signal proportional to its respective bright and dark image.

In order to determine whether the external appearance of a fluorescent lamp is good or bad using such a device, select a fluorescent lamp that is determined to be good, and use the obtained light level and the preset upper limit width,
The upper limit value and lower limit value for each element determined by the value of the lower limit width are compared, and a defective product signal is output when the detection signal level is higher than the upper limit level or lower than the lower limit level.

However, according to this device, when a lamp mark or the like is stamped on the bulb surface, the reflected light from the lamp mark is mapped to the lamp mark in advance, such as when the stamping position of the lamp mark varies due to manufacturing. This method has disadvantages such as the fact that it is impossible to actually inspect the bulb surface on which the lamp mark is affixed unless it is possible to reliably correspond to each element.

OBJECTS OF THE INVENTION The present invention was made in order to eliminate such drawbacks, and provides a method for determining whether a tube is good or bad, which can improve reliability in determining whether a tube is good or bad.

Structure of the Invention The method of determining the quality of a tube according to the present invention includes disposing a bulb to be inspected between a light source and a photoelectric conversion camera, projecting light from the light source to the bulb, and inspecting the bulb. The bulb is rotated in the circumferential direction, and a photoelectric conversion camera detects the contrast image of the bulb surface due to the light transmitted from the pulp, and the photoelectric conversion camera generates an electrical signal at a level corresponding to the bulb surface condition. Converting an electrical signal into an integral signal, comparing the level of the electrical signal with the level of the integral signal, and generating a defective product signal only when the level of the electrical signal exceeds the level of the integral signal; The quality of the tube is determined based on whether or not a non-defective signal is generated.

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

In Fig. 1, reference numeral 1 denotes a tube, such as a fluorescent lamp in which a phosphor coating is formed on the inner surface of a cylindrical bulb.The surface of this bulb is illuminated by a light source 2, and the light transmitted from this bulb is used as a photovoltaic device. It is detected by the conversion camera 3. This photoelectric conversion camera 3 is equipped with a lens and a photoelectric conversion element array divided into a plurality of pieces, so-called an image sensor. The light signal of the bright and dark image of the bulb surface focused by the lens is imaged on the internal photoelectric conversion element, and each photoelectric conversion element generates an electric signal proportional to the bright and dark image. The number of photoelectric conversion cameras 3 to be installed increases or decreases in proportion to the length of the fluorescent lamp to be inspected, but in the case of a 40 Watt fluorescent lamp, two cameras are required. Photoelectric conversion camera 3
The electrical signal outputted from is input directly to the comparator 6 , and is also converted into an integral signal by the integrating circuit 6 via the amplifier circuit 4 and input to the comparator 6 . A comparator 6 compares the electrical signal and the integral signal. The output of comparator 6 is input to logic storage circuit 7.

In the case of fluorescent lamps with no defects on the bulb surface,
As shown in a) and (b), the level of the electrical signal from the photoelectric conversion camera 3 is always lower than the level of the integrated signal from the integrating circuit 6, so no defective product signal is generated, as shown in (O)K in the figure. .

7-2 The electric signal of the camera 3 becomes as shown in Fig. 3 (!L), and the integrated signal of the integrating circuit 5 becomes as shown in Fig. momentarily exceeds the level of the integrated signal of the integrating circuit 5, and at this time a defective product signal is generated from the logic storage circuit 7 as shown in FIG. In practice, such an operation is performed, for example, in the shipping inspection process, and by inputting the obtained defective product signal into a storage circuit (not shown), a product with a defective phosphor coating can be removed from the process at an arbitrary position. Exclude.

The above-mentioned quality determination can be performed on the entire valve by rotating the valve in the circumferential direction.

As described above, in determining the quality of the tube, the output (integral signal) of the integrating circuit 5 is used as a reference signal for the quality determination level along the tube axis of the fluorescent lamp to be inspected. By using the integral signal, the output from the photoelectric conversion camera 3 (
It is possible to create a pass/fail judgment level that fluctuates from moment to moment by responding to electrical signals (7, -). In this way, it is difficult to detect defective products based on the absolute level of the output of the photoelectric conversion camera 3, but instead to compare the levels of the output of the photoelectric conversion camera 3 and the output of the integrating circuit 6. Therefore, compared to the invention shown in Japanese Patent Application Laid-Open No. 57-9034, even in the case of a fluorescent lamp with a lamp mark stamped on it, this method can be used reliably without any adverse effects such as misalignment of the lamp mark. This is advantageous in that it can detect changes in the projected illuminance level and follow changes in the photoelectric conversion camera 3 over time.

Note that the magnitude of the integration constant in the integration circuit 5 is proportional to the time lag between input and output signals. When the integral constant is relatively small, the output of the integrating circuit 6 and the level of the electrical signal from the optical camera 3 almost never exceed the level of the integrated signal from the integrating circuit 5, making it difficult to detect defective products. On the other hand, due to mismatching of the electrical signals of the photoelectric conversion camera 3 that occurs every time the photoelectric conversion element of the photoelectric conversion camera 3 scans, there is an increased possibility that a non-defective product will be determined as a defective product.

Conversely, when the integral constant is large, the integral signal from the integrating circuit 5 has a relatively large time delay compared to the electrical signal from the photoelectric conversion camera 3, so Even if the photoelectric conversion camera 3 The potential for signal mismatch is reduced.

Therefore, the integration constant of the integration circuit 6 is disadvantageous if it is too large or too small, and has a certain optimum value. In the case of this example, the most preferable value confirmed through experiments is R
= 40 Ω, C = 0.01 μF.

In addition, in the above embodiment, the case where the quality judgment is performed on fluorescent lamps is explained, but the present invention also provides a colored coating 2 on the bulb.
Needless to say, it is possible to determine whether a tube having reflected wave deposits or the like is good or bad.9,-2.

As described in detail, the present invention projects light from the projecting light source onto a bulb to be inspected disposed between the projecting light source and the photoelectric conversion camera, rotates the bulb in the circumferential direction, and removes light from the bulb. A photoelectric conversion camera detects the contrast image of the bulb surface due to the transmitted light, and this photoelectric conversion camera generates an electrical signal corresponding to the bulb surface condition, converts this electrical signal into an integral signal, and compares both signals. , a defective product signal is generated only when the level of the electric signal exceeds the level of the integral signal, and the quality of the bulb is determined based on whether or not this defective product signal is generated, so that lamp marks etc. are not imprinted. It is possible to reliably determine whether a fluorescent lamp is good or bad, and reliability can be improved compared to the conventional method. In addition, it can track changes in the illuminance level of the floodlight and changes over time in the photoelectric conversion camera, which eliminates the need to readjust the discrimination circuit each time. This is something that can be further improved.

10, -mi

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of an apparatus for carrying out the method of determining the quality of a tube according to the present invention, and FIG. 2 (2L), (b), (
C) shows various waveform diagrams of the same device in the case of a non-defective product, and Figure 3 (aL) (b) and (C) show various waveform diagrams of the same device in the case of a defective product. , 2... floodlight source, 3...
...Photoelectric conversion camera, 4...Amplification circuit, 5
...Integrator circuit, 6...Comparator,
7...Logic memory circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person @1
Figure 2 Figure 3 - Cuff 8. I Placement ゛.

Claims (1)

[Claims] A bulb to be inspected is placed between a light source and a photoelectric conversion camera, the light from the light source is projected onto the bulb, the bulb is rotated in the circumferential direction, and the light transmitted from the bulb is measured. A contrast image of the bulb surface caused by light is detected by the photoelectric conversion camera, and an electric signal of a level corresponding to the state of the pulp surface is generated from the photoelectric conversion camera, and the electric signal from the photoelectric conversion camera is integrated into an integral signal. The level of the electric signal is compared with the level of the integral signal, and a defective product signal is generated only when the level of the electric signal exceeds the level of the integral signal, and it is determined whether or not this defective product signal is generated. A method for determining whether a tube is good or bad, characterized by determining whether the tube is good or bad.