JPS61181905A - Film thickness measuring apparatus - Google Patents

Abstract

PURPOSE:To enable measurement of a curved shape of a painted tube by installing a photo-source in an opening for an object to be measured in a closed vessel and receiving the brightness of a light passing through a film of a painted tube on a photo-sensor as an indirect light. CONSTITUTION:A box-shaped closed vessel 8 coated with a white paint to diffuse and reflect a light on its inside surface is equipped with a standard tube and a door for inlet and outlet of an object to be measured at its side portion. A photo-source 2 is installed at the bottom of the closed vessel 8 so as to be able to insert into the respective openings of the standard tube and the painted tube 5 which is an object to be measured. A photo-sensor 4 is installed on the ceilling surface of the closed vessel 8 opposite to the photo- source 2 and a gobo 10 is placed to block up the surface of the photo-sensor 4 facing to the photo-source 2 so that a light from the photo-source 2 can not be directly incident to the photo-sensor 4 and is consisting of a non-transparency material. Under such an arrangement, the photo-sensor 4 and have an incidence of an indirect light which comes in from the side direction of the gabo 10 after passing through the painted tube 5 and reflecting at the wall surface of the closed vessel 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for measuring the film thickness of a fluorescent film or a diffusion film coated on the inner surface of a glass tube of a bulb such as a light bulb or a fluorescent lamp.

[Conventional technology]

Figure 3 is a cross-sectional view showing a conventional film thickness measuring device. In Figure 2, (1) is the tube on the light source side, (2) is the light source installed in this tube (1), and (3) is the light receiving device. In the tube on the side.

(4) is a photosensor installed inside this tube (3). And these cylinders +11. +3) are installed at a predetermined distance from each other, and the light source (2)
The light can enter the photo sensor (4).

(5) is a straight glass tube (hereinafter referred to as a coated tube) whose inner surface is coated with a phosphor to be measured. (6) is a DC power supply for the light source (2), and (7) is a variable resistor that adjusts the brightness of the light source (2).

The conventional film thickness measuring device configured as described above is as follows.

First, a standard tube (not shown) whose film thickness is known in advance.
is attached closely between the tube on the light source side (1) and the tube on the light receiving side (3), and the light emitted from the light source [2] is received by the photosensor (4) through the coating film of the standard tube. .

Next, the brightness of the light source (2) is adjusted using a variable resistor (71), and the output of the photosensor (4) is set to an arbitrary value.

After this, the standard tube is removed and the coating tube (5) to be measured is measured in the same manner. Then, the film thickness of the coating tube (5) was calculated from the difference in light transmittance between the standard tube and the coating tube (5).

[Problem that the invention seeks to solve]

However, since the coating tube (5), which is the object to be measured, was installed between the tube (1) on the light source side and the tube (3) on the light receiving side as described above, the coating tube (5) had a curved shape. 5) 2 For example, the curved portion of a 7-shaped tube causes light leakage in which the light from the light source (2) is directly irradiated onto the photosensor (4), making it difficult to measure the film thickness.

This invention was made with the aim of improving these drawbacks, and provides a film thickness measuring device that can measure even curved coating tubes and can measure the average film thickness of the entire coating tube in one go. This is what we are trying to provide.

[Means for solving problems]

The film thickness measuring device of this invention is one in which a light source is inserted into the opening of the object to be measured in a sealed container, and the brightness of the light passing through the film of the coating tube is received as indirect light by a photosensor. be.

[Effect]

In the measuring device of the present invention, since the light source is located inside the part to be measured, the light from the light source is transmitted outward from the entire inner surface of the part to be measured. In addition, this transmitted light is diffusely reflected by the inner surface of the sealed container and enters the photosensor, so the film thickness of the object to be measured may be uneven, or the shape of the object to be measured may be bent. Even if the shape is complex, an averaged amount of light is incident on the photo sensor. Therefore, the amount of the object to be measured is also the area where light can easily pass through (
It is possible to prevent the film from being affected by the amount of light at the point where the film thickness is the thinnest, thereby making it possible to measure the average film thickness.

〔Example〕

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
] is a rectangular box-shaped airtight container whose inner surface is coated with white paint that diffuses and reflects light, and is equipped with a door (9) on the side of the tube for loading and unloading standard tubes and objects to be measured. Reference numeral (2) denotes a light source, which is placed at the bottom of the sealed container (8) that can be inserted into the openings of the standard tube and the coating tube (5) that is the object to be measured. (4) is a closed container (
8) is a photosensor attached to the top surface. α
Q is a light shield formed of an opaque material arranged to cover the surface of the photosensor (4) on the light source (2) side so that the light from the light source (2) does not directly enter the photosensor (4). It is a board. However, in this state, the photo sensor (4
), the light that has passed through the application tube (5) can enter from the side of the S base plate aQ as indirect light that is reflected on the wall surface of the closed container (8).

(6) is a DC power source that lights up the light source (2), and (7
) is a variable resistor that adjusts the brightness of the light source +21.

To measure the film thickness of the U-shaped coating tube (5) with the film thickness measuring device configured as described above, first, use a U-shaped standard tube whose film thickness is known in advance as shown in Figure 1. It is installed in a sealed container (8), and the light source (21) is connected to the variable resistor (7) K.
Adjust the brightness of the photo sensor (4) and set the output of the photo sensor (4) to an arbitrary value. Next, the coating tube (5) is attached in the same way as the standard tube, the output of the photosensor (4) is read, and the film thickness of the coating tube (5) is calculated from the difference between the output and the standard tube.

In the above embodiment, the coating tube (5) was a U-shaped tube, but the film thickness can be measured in the same way with a bispherical coating tube (5).

Figure 2 shows an embodiment for measuring the film thickness of the spherical coating tube (5). The coating tube (5) is attached to the opening 5, and the film thickness can be measured in the same manner as in the above embodiment.

〔Effect of the invention〕

As described above, the present invention includes a sealed container having an inner surface as a light reflecting surface, a light source provided to be exposed in the sealed container, a measured object that can contain the light source, and a device to be measured that is provided in the sealed container and described above. A light-shielding plate is formed to block the light from the light source directly emitted through the object to be measured, but to allow indirect light to enter, and the indirect light from the light source that is exposed in the sealed container and enters through the light-shielding plate is provided. Equipped with a photosensor that receives light, the film thickness can be measured even if the object is curved or has a variety of shapes, and the average film thickness of the entire object can be measured in one go. There is.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the invention, and FIG. 3 is a sectional view showing a conventional film thickness measuring device. In the figure, (2) is a light source, and (4) is a photosensor. (5) is the object to be measured, (8) is the sealed container, and αQ is the light shielding plate. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] An airtight container with an inner surface as a light reflecting surface, a light source provided to be exposed within the airtight container, an object to be measured that can contain the light source, and a light source provided within the airtight container that emits light directly through the object to be measured. A light-shielding plate configured to block light from the light source but allow indirect light to enter, and a photo sensor that is exposed in the sealed container and receives the indirect light from the light source that enters through the light-shielding plate. Characteristic film thickness measuring device.