JPH06341944A - Light source of measuring machine - Google Patents

Abstract

PURPOSE:To utilize light energy effectively to the maximum extent by providing an elliptic concave mirror on the back of a light source lamp and providing the light source lamp at its focus position. CONSTITUTION:A part of beam emitted from a light source lamp 1 is directly directed toward an object to be measured A, and the remaining beam is once reflected by an elliptic concave mirror 2 and is directed toward the object to be measured A. Since these beams are regulated by an opening amount of a restriction 3 and only the beam which passes through an opening is directed toward the object to be measured A, it is possible to eliminate light which goes beyond the outside of the object to be measured A by adjusting the restriction 3 in accordance with the size of the object to be measured A. Also, as the lamp 1 is provided at a focal point of the concave mirror 2, the light reflected by the concave mirror 2 is converged at the other focus F of an ellipse. Consequently, it is possible to make the reflected light pass the opening securely even if the opening of the restriction 3 is small and utilize light energy of the lamp 1 effectively to the maximum extent. Also, as the object to be measured A is positioned farther from the focus, it is possible to prevent burning on a surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a non-contact optical system for performing various inspections of an object to be measured by irradiating the object to be measured with visible light or infrared rays and receiving and measuring the transmitted light or reflected light thereof. The present invention relates to a light source used in a measuring machine.

[0002]

2. Description of the Related Art The light source of a conventional optical measuring machine usually has the following structure. First, a light source lamp that emits light having a wavelength required for measurement is selected. For example, when using near infrared rays, a halogen lamp or the like is selected. Then, this lamp is placed at the position of the light source, and a concave mirror is installed on the back surface of this light source lamp. In addition, since the purpose of this concave mirror is merely to increase the amount of light directed toward the object to be measured, a concave mirror having an extremely ordinary shape such as a spherical surface is used.

[0003]

However, in the case of measurement using transmitted light, for example, the amount of light at the light receiving portion is extremely small because the light passes through the object to be measured. Therefore, even a small amount of outside light has a great influence on the measured value. For example, when the irradiation width of light is wide and a part of the light sticks out from the object to be measured, this protruding light ray is reflected by other equipment and reaches the light receiving section, and becomes ambient light. However, there is a problem that the measurement accuracy deteriorates and accurate reference cannot be obtained.

Conventionally, a method of bringing a light source into contact with an object to be measured has been used to block such light protrusion. However, in the case of this contact method, it takes time to prepare the measurement for bringing the light emission irradiation member into contact with the surface of the object to be measured, and moreover, the object to be measured being conveyed by the conveyor is continuously measured. It has the drawback of not being available in some cases. In addition, a system in which a diaphragm is installed in front of the object to be measured has been proposed in order to prevent the light from protruding. However, since the concave mirror used here has an ordinary shape such as a spherical surface, the reflected light from the concave mirror does not converge, and a part of the reflected light is blocked by the diaphragm. Has the disadvantage of losing.

In view of the above points, the present invention is a non-contact method,
Moreover, it is intended to provide a light source for a measuring machine, in which a light ray does not stick out to the side of an object to be measured and, moreover, light energy can be utilized to the maximum extent.

[0006]

The technical means of the light source of the present invention comprises a light source lamp, an elliptical concave mirror provided on the back surface of the light source lamp, and a diaphragm provided on the front surface of the light source lamp. Is located at the focal point of the elliptical concave mirror.

Also, it is possible to adjust the aperture of the diaphragm,
Alternatively, the diaphragm may be movable in the optical axis direction.

[0008]

In the light source of the present invention, the elliptical concave mirror is used, and the light source lamp is installed at the focal point of the elliptic concave mirror, so that the light reflected by the concave mirror is focused on the other focal point of the elliptic concave mirror. Become. Further, there is a diaphragm on the front surface of the light source lamp to narrow the irradiation range of the light beam. Therefore,
The light from the light source is surely applied to the object to be measured, and there is no light that runs off the object to be measured and passes through the side of the object to be measured.

In the case where the aperture amount of the diaphragm is adjustable,
The opening amount can be changed according to the size of the object to be measured. Moreover, even if the position of the diaphragm is movable, it can be adjusted according to the size of the object to be measured. Therefore, with such a device, it is possible to increase the irradiation light amount for a large object to be measured and compensate for the decrease in the transmitted light amount.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A light source for a measuring machine according to the present invention will be described with reference to the embodiments shown in the drawings. Reference numeral 1 denotes a light source lamp, which has a desired wavelength and light amount and is appropriately selected and used. Reference numeral 2 is a concave mirror, and the inner surface is an elliptic curved surface. The light source lamp 1 is placed at one focus position on the elliptic curved surface. Therefore, from the light source lamp 1,
The light rays reflected by the concave mirror 2 are focused on the other focus of the elliptic curved surface.

Reference numeral 3 is a diaphragm, the opening amount of which is adjustable, and can be adjusted according to the size of the object A to be measured. If the front surface of the object A to be measured is set at the focal point F of the light beam, the object to be measured may be scorched when the light beam is strong. It is preferable to shift it to a distance. In the figure, 4 is a condenser lens, 5
Is a slit, and 6 is a light receiving sensor.

Next, the light irradiation of the light source will be described. A part of the light beam emitted from the light source lamp 1 is directly directed toward the object to be measured A, and the rest is once reflected by the concave mirror 2 toward the object to be measured. In addition, a diaphragm 3 is provided in front of the light source lamp 1.
Is provided, the light emitted from the lamp is regulated by the opening amount of the diaphragm 3, and only the light passing through the opening goes to the object A to be measured. Therefore, by adjusting the diaphragm 3 according to the size of the object to be measured A, it is possible to eliminate the light that passes through the outside of the object to be measured A.

Further, the light reflected by the concave mirror 2 is focused on the other focus F of the ellipse because the light source lamp 1 is located at one focus of the elliptical concave mirror 2. Therefore, even when the aperture of the diaphragm 3 is small, the reflected light from the concave mirror 2 can be surely passed, the light energy of the lamp can be utilized to the maximum extent, and waste can be eliminated. Also, the object to be measured A
Is located at a distance from the focal point F, so that it is possible to prevent the surface from sticking.

Thus, the light emitted from the light source definitely hits the object A to be measured, passes through the object A, and is affected by the internal properties of the object D during the passage. Therefore, the internal properties of the object to be measured A can be known by condensing the transmitted light with the lens 4, passing through the slit 5, and detecting the light reception with the sensor 6.

The light source of the present invention is not limited to the above embodiment, but can be freely modified within the scope of the claims. In particular, the type and wavelength of the light beam, the type of measurement method such as the transmission method or the reflection method, the configuration of the light receiving unit, and the purpose of measuring what is inspected are completely free. Further, the stop may be installed before or after the focus.
Further, the adjustment depending on the size of the object to be measured can be achieved not only by changing the opening amount of the diaphragm, but also by fixing the opening amount and moving the position of the diaphragm back and forth in the optical axis direction.

[0016]

According to the light source of the present invention, since the range of the irradiated light is narrowed in area according to the size of the object to be measured, all the light from the light source hits the object to be measured, There is no light passing outside the object. Therefore, the light-receiving unit is not affected by the disturbance caused by the protruding light, and can perform high-accuracy measurement, and can accurately perform reference acquisition and the like.
Furthermore, since the elliptical concave mirror is used, the energy of the light source can be utilized to the maximum extent.

According to the second aspect of the present invention, since the aperture amount of the diaphragm can be adjusted according to the size of the object to be measured, the amount of transmitted light decreases as the object to be measured increases. The cover can be provided, the amount of received light can be stabilized, and the measurement can always be performed with high accuracy.

According to the third aspect, the same effect as that of the second aspect can be achieved by moving the position of the diaphragm according to the size of the object to be measured.

[Brief description of drawings]

FIG. 1 is a diagram showing a light irradiation state when a light source of the present invention is used.

[Explanation of symbols]

 1 Light source lamp 2 Elliptical concave mirror 3 Aperture 4 Lens 5 Slit 6 Light receiving sensor

Claims (3)

[Claims] 1. A measuring instrument comprising a light source lamp, an elliptical concave mirror provided on the back surface of the light source lamp, and an aperture stop provided on the front surface of the light source lamp, the light source lamp being installed at the focal point of the elliptical concave mirror. Light source. 2. The aperture of the diaphragm is adjustable.
The light source of the measuring instrument described. 3. The light source for a measuring machine according to claim 1, wherein the diaphragm is movable in the optical axis direction.