JPH0463497B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field 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. be.

Conventional structure and its problems Conventionally, determining whether the appearance of tubes such as fluorescent lamps is good or bad has been based on visual inspection with the naked eye, which has poor inspection efficiency and is not always reliable in determining whether it is good or bad. There were flaws. In order to eliminate these drawbacks, a tube surface inspection device using a photoelectric conversion camera has been proposed, as disclosed in Japanese Patent Application Laid-Open No. 57-9034. 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.
A projecting light source is provided outside the area connecting the camera and the bulb to illuminate the bulb surface, 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 appearance of a fluorescent lamp is good or bad using such a device, a fluorescent lamp that is judged to be of good quality is set up, and the obtained light level and the preset upper and lower limit widths are measured. The upper limit value and lower limit value for each element determined by the value 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 drawbacks such as the fact that it is impossible to actually inspect the bulb surface on which the lamp mark is affixed because it cannot reliably correspond to each element.

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

Structure of the Invention The method for determining the quality of a tube according to the present invention includes disposing a cylindrical bulb to be inspected between a light source and a photoelectric conversion camera, and projecting light from the light source to the bulb. Then, rotate this valve in the circumferential direction,
A method of detecting a brightness image of a bulb surface caused by transmitted light from the bulb using a photoelectric conversion camera, and generating an electrical signal at a level corresponding to the bulb surface condition from the photoelectric conversion camera, thereby detecting the surface condition of the bulb surface. The bulb is positioned such that the bulb axis is perpendicular to the optical axis of the lens of the photoelectric conversion camera, and the light beam is located within a bulb plane having a circular cross section perpendicular to the bulb axis. In the plane of the valve having a diameter in perpendicular relation to the axis, from each point on each radius of said diameter and spaced from the end of each radius by one-fifth of the length of the radius. , when the points where four line segments extending parallel to the optical axis on the lens side intersect with the circle are sequentially defined as first, second, third and fourth points, the first and fourth points At least one of the two arc regions between the two points and between the third and fourth points is set as the detection range of the photoelectric conversion camera.

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, for example, a fluorescent lamp with a phosphor coating formed on the inner surface of the cylindrical bulb.A light source 2 emits light onto the surface of the bulb, and the transmitted light from the bulb is converted into a photoelectric lamp. 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, a so-called image sensor. An optical signal of a bright and dark image of the bulb surface focused by the lens is imaged on an 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. The electrical signal output from the photoelectric conversion camera 3 is sent to a comparator 6.
The signal is input directly to the signal generator, and is converted into an integral signal by an integrating circuit 5 via an amplifier circuit 4, and then input to a comparator 6. A comparator 6 compares the electrical signal and the integral signal. Comparator 6
The output is input to the logic storage circuit 7.

In the case of a fluorescent lamp with no defects on the bulb surface,
As shown in FIG. 2a 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 5, so as shown in FIG. 2c,
No defective product signal is generated.

On the other hand, in the case of a fluorescent lamp with a defect on the bulb surface, for example, a fluorescent lamp whose fluorescent lamp coating has fallen off, the electrical signal of the photoelectric conversion camera 3 becomes as shown in FIG. 3a, and the integrating circuit 5 The integrated signal becomes as shown in FIG. This occurs as shown in c. 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 defective product with a phosphor coating can be detected at an arbitrary position. Exclude from the process.

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

In the method of the present invention, in order to improve the accuracy of pass/fail determination, it is extremely important that the amount of transmitted light from the lamp to be inspected that enters the photoelectric conversion camera 3 is uniform and large along the lamp tube axis.

FIG. 4 shows the diameter of a bulb plane perpendicular to the optical axis 9 of the photoelectric conversion camera 3 in a bulb plane having a circular cross section perpendicular to the bulb axis 10 of the fluorescent lamp 1, which is the lamp to be inspected. When expressed as a percentage of the distance from the end of the bulb plane 11 when the length of its radius is 100, the distance from each point indicated by the percentage extends parallel to the optical axis toward the photoelectric conversion camera 3 side. The line segments each indicate the relative value of the amount of transmitted light of the lamp to be inspected on the arc intersecting the circle. As is clear from the figure, the intensity of the transmitted light of the lamp to be inspected is at the 0% point, that is, at the center of the circular bulb plane, the line segment extending parallel to the optical axis toward the photoelectric conversion camera intersects the circle. At the point, the stem part 1 sealed at the lamp end, as shown in FIG.
It becomes the lowest since it becomes a shadow of 7, and it reaches the highest around 60% because the influence decreases. In addition, the 6th
In the figure, 18 is a filament coil, 19 is a flare, 20 is a valve, and 21 is a flare 19 and a valve 2.
The sealing portion with 0 is shown respectively.

On the other hand, the relative value of the area to be inspected on the bulb plane 11 to the plane containing the line segment 12 perpendicular to the optical axis 9 of the photoelectric conversion camera is, conversely,
It is maximum at 0%, decreases monotonically as the percentage increases, and reaches minimum at 100%. Practically, in order to inspect the bulb surface with high precision, a plane with sufficient intensity of transmitted light and including a line segment 12 perpendicular to the optical axis 9 of the camera of the area to be inspected on the bulb plane 11 is required. It is extremely important that the relative value of the projected area to the area does not become too small.

According to experiments, the regions that satisfy this requirement are on each radius of the line segment 12 indicating the diameter, and are separated by 1/5 of the length of the radius from the end of each radius. One of the points 13, 14, 15 and 16 where four line segments extending parallel to the optical axis from the point to the lens side intersect the circle.
Between points 3 and 14, or between points 15 and 1
It was an arc area between the 6 points. Therefore,
If these are set as the detection range of the camera, it is possible to perform a quality inspection of the phosphor coating with higher accuracy than in the conventional example.

Further, even if a lamp mark or the like is stamped, accurate determination of quality can be performed with high reliability.

In the above embodiment, a case was explained in which the quality judgment was made for a fluorescent lamp, but the present invention is applicable not only to a light bulb having a colored coating, a reflective coating, etc. on the bulb, but also to a bulb having a cylindrical bulb. This method can be applied to other tubes.

Effects of the Invention As explained above, the present invention makes it possible to further stabilize the transmitted light of the lamp to be inspected along the tube axis, thereby reducing inspection errors and improving reliability. This makes it possible to provide a highly efficient method for determining whether a tube is good or bad.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a device for carrying out the method of determining the quality of a tube according to the present invention, Fig. 2 a, b, c
are various waveform diagrams of the same device in the case of non-defective products, 3rd
Figures a, b, and c are various waveform diagrams of the same device in the case of defective products. Figure 4 is a diagram of the relationship between the relative length of the line segment on the radius measured from the center of the circle and the relative value of the amount of transmitted light. FIG. 5 is a diagram showing the arrangement relationship of the photoelectric conversion camera, the lamp to be inspected, and the projecting light source, and FIG. 6 is a sectional view showing the stem portion sealed at the end of the lamp. 1...Tube, 2...Projecting light source, 3...Photoelectric conversion camera, 4...Amplification circuit, 5...Integrator circuit, 6...
... Comparator, 7 ... Logical memory circuit, 8 ... Relative value of the intensity of transmitted light corresponding to the appearance state of the lamp to be inspected, 9 ... Optical axis, 10 ... Tube axis, 11 ... Bulb plane, 12 ... Line segment, 13, 14, 15, 1
6... point, 17... stem part, 18... filament coil, 19... flare, 20... valve,
21...Sealing part.

Claims (1)

[Claims] 1. A cylindrical bulb to be inspected is arranged between a floodlight source and a photoelectric conversion camera, and the light from the floodlight source is projected onto the bulb, and the bulb is rotated in the circumferential direction. The photoelectric conversion camera detects a contrast image of the bulb surface caused by the light transmitted from the bulb, and the photoelectric conversion camera generates an electrical signal at a level corresponding to the bulb surface condition, thereby detecting the surface condition. It is a method to
The bulb is positioned so that the bulb axis is perpendicular to the optical axis of the lens of the photoelectric conversion camera, and the bulb plane with a circular cross section perpendicular to the bulb axis is perpendicular to the optical axis. From each point on each radius of said diameter and spaced from the end of each radius by one-fifth of the length of the radius, in the plane of the bulb with diameters in the relationship The points where four line segments extended parallel to the optical axis intersect with the circle are sequentially 1,
When the second, third and fourth points are
and a method for determining the quality of a tube, characterized in that at least one of two arc regions between the second points and between the third and fourth points is set as a detection range of the photoelectric conversion camera.