JPH0473739B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an optical measurement probe, and more specifically, the present invention relates to an optical measurement probe that irradiates a sample with diffused light and receives the reflected light from the sample using an optical fiber. , relates to an optical measurement probe suitably used when measuring optical properties of a sample.

<Prior Art> Conventionally, a probe having the configuration shown in FIG. 2 has been provided in order to measure the optical characteristics of a sample.

To explain in more detail, a light source 23 and a reflecting mirror 24 are arranged in the large diameter part 22 of the cylindrical case 21 whose lower part has a small diameter, and the light emitted from the light source 23 is efficiently guided toward the small diameter part 25. That's what I do. The lower end opening of the small diameter section 25 is configured to face the sample S in close contact with the sample S, and the inner surface of the small diameter section 25 is formed as a light reflecting surface 26 with high reflection efficiency, and the upper end of the small diameter section 25 A light transmission type diffuser plate 27 is attached to cover the area. Furthermore, an optical fiber 28 for receiving light is attached to pass through a predetermined position of the light-transmitting diffuser plate 27, and a light-transmitting auxiliary diffuser plate 29 is attached to the tip of the optical fiber 28. . still,
30 is a color complementation conversion filter or an interference filter (see Japanese Patent Laid-Open No. 60-202317).

Therefore, the light emitted from the light source 23 is efficiently guided to the light transmission type diffuser plate 27, and the light uniformly diffused by the diffuser plate 27 and the auxiliary diffuser plate 29 is efficiently guided to the sample S by the light reflecting surface 26. It can be irradiated.

Then, the reflected light from the sample S is transferred to the optical fiber 28.
By receiving the light and guiding it to an analysis device (not shown), color information etc. of the sample S can be obtained.

<Problems to be Solved by the Invention> In the probe with the above configuration, a part of the reflected light from the sample S is reflected again by the diffuser plate and is irradiated onto the sample S. This results in the same result as if the light irradiated onto the sample S changes depending on the color, reflectance, etc., and there is a problem that accurate measurement results cannot be obtained.

Further, although correction is performed from 0 to 100% based on a standard white reflector whose reflectance is known and the dark state, there is a problem in that complete correction cannot be expected. In particular, the reflected light from the sample S is reflected multiple times by the light reflecting surface 26 and the diffusion plates 27 and 29 before being irradiated onto the sample S again. Since it is determined based on the reflectance, it is extremely difficult to perform correction, and as a practical matter, it is impossible.

<Purpose of the Invention> This invention was made in view of the above problems, and it is an object of the present invention to prevent light that has been reflected from a sample more than once from being irradiated onto the sample again, thereby improving the uniformity of the irradiated light. The object of the present invention is to provide an optical measurement probe that can perform accurate optical measurements.

<Means for Solving the Problems> In order to achieve the above object, the optical measurement probe of the present invention has a light source disposed at one focus of a condensing system having two focal points, and a light source disposed at one focus of a condensing system having two focal points. A micro-sized light-transmitting type diffuser plate is disposed at the focal point of the mirror. The optical fiber is disposed at the center of the optical trap attached to the sample, and an optical fiber is disposed at a predetermined position where it can receive reflected light from the sample.

However, it is sufficient that the optical fiber is placed at a position where it can receive reflected light from the entire sample depending on the aperture angle, but the optical fiber may be placed so that the light-receiving end surface of the optical fiber is flush with the diffuser plate. It is preferable that the

Furthermore, it is preferable that the outer surface of at least the portion of the optical fiber located inside the optical trap is formed in black.

<Function> With the optical measurement probe configured as described above, the light from the light source can be efficiently guided to the microscopic light-transmitting diffuser plate by the condensing system, and can be uniformly diffused through the diffuser plate. The reflected light is efficiently guided to the surface of the sample by the mirror cylinder. A part of the reflected light from the sample is received by an optical fiber,
The remaining reflected light is absorbed by the optical trap, so the sample is irradiated with only the light that has passed through the diffuser plate and is uniformly diffused, and the light that has been reflected from the sample one or more times is irradiated onto the sample again. You can prevent this from happening.

Furthermore, although the optical fiber is arranged at a position where it can receive reflected light from the entire sample due to its aperture angle, it is possible to receive reflected light from the entire range of the sample with the optical fiber, and in particular, the above-mentioned light If the light-receiving end face of the fiber is arranged flush with the diffuser plate, the optical fiber will not block the diffused light irradiating the sample, and the diffuser plate will block the reflected light from the sample. There are no problems, which is preferable.

Furthermore, it is more preferable if the outer surface of at least the portion of the optical fiber located inside the optical trap is formed black, since the reflected light from the sample will not be reflected by the side surface of the optical fiber.

<Examples> Hereinafter, examples will be described in detail with reference to the accompanying drawings showing examples.

FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of the optical measurement probe of the present invention, which includes a light source 1, a condensing mirror 2, a light-transmissive diffuser plate 3, and a mirror cylinder 4.
, an optical fiber 5 , and an optical trap 6 .

More specifically, the light source 1 has a size that can be simulated as a point light source, and is placed at one focal point of a condensing mirror 2 made of an ellipsoidal mirror. At the other focal point of the condensing mirror 2, a microscopic light-transmissive diffuser plate 3 is disposed.

Therefore, the light emitted from the light source 1 can be efficiently guided to the micro-sized diffuser plate 3.

Further, the mirror-finished cylinder 4 is mirror-finished (for example, by vapor deposition of chromium, aluminum, etc.) over a predetermined range from the opening on the side where the sample S is disposed. The above-mentioned diffusion plate 3 can be disposed corresponding to the terminal position, so that the sample S can be efficiently irradiated with all the uniformly diffused light emitted from the diffusion plate 3.

Next to the end position of the mirror finishing of the mirror barrel 4, an optical trap 6 is disposed, the tip side of which gradually contracts outward, and the inner surface of which is black. The above-mentioned diffuser plate 3 is attached to a light passage portion formed at the center of the light transmitting member 6 . Furthermore, an optical fiber 5 for receiving reflected light from the sample S is attached to pass through a predetermined position of the optical trap 6.

The optical fiber 5 may be attached as long as the aperture angle at the light-receiving end surface covers the entire range of the sample S, and it is most preferable to attach it flush with the diffusion surface of the diffusion plate 3.

Therefore, depending on the outer shape of the optical trap 6,
The light from the light source 1 can be reliably guided to the diffuser plate 3, and the reflected light from the sample S can be effectively absorbed, thereby reliably preventing the inconvenience of the sample S being irradiated again.

The operation of the optical measurement probe having the above configuration is as follows.

Almost all of the light emitted from the light source 1 is guided to the diffuser plate 3 by the condensing mirror 2, and the diffused light that is uniformly diffused after passing through the diffuser plate 3 is reflected on the inner surface of the mirror cylinder 4. The light is efficiently reflected and guided to the sample S.

That is, the sample S is irradiated with uniformly diffused light.

A portion of the reflected light from the sample S is incident on the light-receiving end face of the optical fiber 5, and is guided to a measuring device (not shown) to obtain color data and the like.

Further, the remaining reflected light is guided to the optical trap 6, where it is effectively absorbed, and it is possible to reliably prevent the sample S from being irradiated again.

In this case, even after being guided into the optical trap 6, it is reflected by the outer surface of the optical fiber 5.
Since there is a possibility that the sample S will be irradiated again,
In order to reliably prevent the sample S from being irradiated again, the outer surface of the optical fiber 5 may be formed black.

The position of the light-receiving end face of the optical fiber 5 may be above or below the diffuser plate 3, but it is necessary that the aperture angle covers the entire measurement range of the sample S. , it is necessary to set the optical fiber 5 at a position where the reflected light from the sample S to be incident on the optical fiber 5 is not blocked by the diffuser plate 3.

Note that the present invention is not limited to the above-mentioned embodiments; for example, a condenser lens may be used in place of the condenser mirror 2, and various modifications may be made without departing from the gist of the present invention. It is possible to make design changes.

<Effects of the Invention> As described above, the present invention reliably prevents the light reflected from the sample from irradiating the sample again.
It has the unique effect of being able to perform accurate optical measurements.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of the optical measurement probe of the present invention, and FIG. 2 is a schematic vertical cross-sectional view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Light source, 2... Condensing mirror, 3... Diffusion plate, 4... Mirror cylinder, 5... Optical fiber, 6...
Light trap.

Claims (1)

[Claims] 1. A light source is disposed at one focal point of a condensing system having two focal points, and a microscopic light-transmitting type diffuser plate is disposed at the other focal point. is placed at one end of the specular tube that efficiently guides the diffused light to the sample, and is also placed in the center of the optical trap attached to one end of the specular tube. An optical measurement probe characterized in that an optical fiber is disposed at a predetermined position capable of receiving reflected light. 2. The optical measurement probe according to claim 1, wherein the optical fiber is disposed at a position where it can receive reflected light from the entire sample depending on the aperture angle. 3. The optical measurement probe according to claim 1, wherein the optical fiber is disposed so that the light receiving end face thereof is flush with the diffuser plate. 4. The optical measurement probe according to claim 1, wherein the outer surface of at least the portion of the optical fiber located inside the optical trap is black.