JPS6035615B2 - Brightness measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus having a function suitable for measuring the brightness of an object placed under special conditions of high or low temperatures or in an electromagnetic field.

When examining the brightness of an object installed at a high temperature of 50 to 100 degrees Celsius or a low temperature of -30 to 0 degrees Celsius, with normal methods, the sensitivity of the receiver changes depending on the temperature, and an external illumination device is required. In luminance meters, measurement errors occur due to the heat resistance of the light source and temperature changes due to lighting.

Furthermore, within the electromagnetic field, noise to the light receiver and noise to the light source become a problem. The present invention provides a device for measuring brightness, etc., which is not affected by the environment, and is used to connect a measurement unit optical system placed in a special measurement environment and a light receiver placed in a normal environment. They are connected by an optical system.

Examples will be described below.

In the figure, a is, for example, a shielding wall of a temperature chamber, and A is a special environment for testing a sample. Further, B is a normal environment maintained at room temperature, for example. 1 is the sample to be measured for brightness, and sample stage 1
9, front and back (X direction), left and right (
Position adjustment is performed in the Y direction), vertical direction (Z direction), and rotational direction.

2 is a taking lens, 3 is a relay lens, 4 is a pinhole plate for determining the measurement range, 5 is a concave lens, 7 is a light guide, one end passes through a hole in shielding wall a, and the end surface 7a is a special It is in environment A.

The other end of the light guide 7 is extended to a location away from the temperature chamber, and is passed through an inkstone sensitivity correction filter 8 to a light receiver 9.
placed opposite. A group of ND filters are inserted in front of the light receiver 9 as appropriate.

Note that the visibility correction filter 8 may be replaced with an interference filter or a spectrometer depending on the purpose. Further, 6 is a vertically movable mirror, which includes a relay lens 11, a prism 12,
A light source from an optical system for projecting a metric indicator consisting of a color filter 13, a light guide 14 and a lamp light source 15 in environment B is used to project onto the sample. 16 more
17 is a taking lens, and 17 is a fiber scope fixed to a support arm (not shown).The end of the fiber scope 17 is placed in environment B, and an eyepiece 18 is provided facing this end surface. .

This observation optical system consisting of 16, 17, and 18 is used to confirm the state of the sample 1 or the position of the projected index. Ma. In addition, the light guide 20' is a light guide for illuminating the sample, and is fixed to an arm (not shown), and the other end of the light guide 20 faces a lamp light source located in the environment B. Reference numeral 21 denotes a metal filter, which has holes of different sizes in a metal plate, and is used to change the amount of illumination light.

Here, the image of the sample 1 is formed on the pinhole plate 4 by the taking lens 2, and the pupil of the taking lens 2 is reduced and imaged on the end surface 7a of the light guide by the relay lens 3. A concave lens 5 with a short focal length and a rear focus is disposed on this end surface 7a to guide light to the end surface 7a with a pupil image almost at infinity.

The light beam passes through a light guide and is guided to a photoreceiver, allowing measurements to be made in a location unaffected by special environments. Further, the light guide 7 is an optical fiber made of glass or plastic coated with silicon or vinyl chloride, so that electromagnetic noise or thermal transfer does not affect the light receiver. Note that if the relay lens 3 includes a lens that performs the same function as the concave lens 5, the concave lens 5 can be omitted.

As mentioned above, Miyakomura 2, 6, 11, 12, 13, 14, 1
The optical system consisting of 5 is an optical system that projects the index, and the optical system consisting of 16
, 17, and 18 is an optical system for confirming the measurement location of the object to be measured and further visualizing the surface condition of the object to be measured. (The mirror will be raised during measurement.)

), a prism 12 and a lens 1 arranged to guide the light emitted from the light source 15 provided in the environment B into the environment A through the inside of the light guide 14 and bend the direction of the light.
1 and illuminates the pinhole plate 4 via the mirror 6. Then, the pinhole of the pinhole plate 4 forms a projected image on the sample 1 by the taking lens 2. By adding the color filter 13 here, the light has a different color from the illumination light of the light source of the sample illumination optical system, making it easier to see. In addition, since it is easier to see if the light intensity of the light source 22 of the illumination optical system is reduced by the metal filter 21, the vertical movement of the mirror 6 and the metal filter 2
It is better to insert 1 in conjunction with each other. Note that the installation location of the mirror 6 is not limited to between the pinhole plate 4 and the IJ relay lens 3, but may be between the relay lens and the concave lens 5. The location where this projected image appears is the measurement point of the sample 1 and the size of the measurement range. Confirmation of the measurement point or confirmation of the state of the sample surface is performed by self-view in the normal environment B using a fiberscope 17 equipped with a taking lens 16 and an eyepiece 18. Next, if the sample itself does not emit light, it is necessary to illuminate the sample, and an optical system consisting of members 22, 21, and 20 is used.

The light guide 2 transmits the light from the light source 22 placed in the normal environment B.
0 into the special environment A and illuminate the sample.

When changing the illumination angle to the sample, it is done by rotating the fixed arm (described later) of the light guide attached to the sample stage 19, but if the light guide is a single fiber, the illumination angle is Furthermore, in order for the arm to rotate freely, the length of the light guide 20 must be made considerably long, which is a loss in light quantity and requires a large space. In addition, the light guide is often twisted as the arm rotates, and there is a drawback that fibers may be damaged due to twisting, especially at low temperatures. The sample stage shown in FIG. 2 has improved the above-mentioned drawbacks.
100 is a stand, 101 is a disk for attaching a sample, 10
2 is an arm, and arm 102 is a stand 100 and a disk 101
It is fixed to a cylinder 103 which is rotatable about a shaft connecting the two.

The end portion 107C of the light guide 107 for illumination is arranged in a circular shape, and the light guide 10 is arranged so as to face this circular end surface.
An end portion 107b of 7d is also formed. A spacer made of a translucent material is provided between the two light guide end faces 107c and 107b.
By arranging the light guides 108 and separating them by a small amount, uneven illumination of the light guides can be avoided.

Here, the spacer 108 may not be provided and the spacer 108 may be separated by a small amount. The illumination light guide 107b may be solid, and is placed inside the arm 102. Further, 107a is a light emitting end. When installing a light guide, light guide 1
By making the diameter of the fibers constituting the light guide 107d larger than the fiber diameter of the light guide 107d, if the position of the arm moves east of the light emitted from the light emitting end, that is, the end faces 107c and 107b
can be kept constant even if the relative rotation occurs. In the above device, the optical system consisting of members 2, 4, 3, and 5 has measurement errors due to unevenness due to the difference in the angle of incidence on the light guide 7 used for measurement away from the sample, or unevenness in bundling of the light receiving end of the light guide. , problems such as a decrease in light intensity due to fiber defects can be solved.

Also, by projecting the pupil of the taking lens a little vertically, a light guide with a small diameter can be used. The above reasons will be explained in comparison with a commonly known optical arrangement consisting of a sample 200, a lens 201, an aperture 202 (corresponding to a pinhole in the present application), and a light guide 203 shown in FIG.

Figure 4 is a front view of the light guide, with 204
205 is a portion where the fibers are dense, and 205 is a portion where the fibers are coarse. As shown in Figure 3, since the incident angle of light differs depending on the F number of the lens 201, the transmittance is better when the incident angle is perpendicular to the fiber end face.The amount of light transmitted through the fiber varies depending on the location according to the properties of the fiber itself. .

For this reason, if the aperture diameter of the aperture 202 is large, the brightness at the center of the measurement range will be more emphasized than at the periphery, which will appear in the measured value. In addition, if the fibers are unevenly bundled as shown in Figure 4, the light-receiving area on the light guide will also change when the diameter of the aperture 202 is changed. The result is that the receiver does not respond as the aperture diameter changes.

In contrast, in this application, by providing a concave lens between the relay lens and the light guide, it is possible to soften the steep angle of light rays that occur at the periphery of the measurement range, and to reduce the steepness of the light rays when they enter the fiber. Since the loss is reduced, a corresponding output can be obtained even if the aperture size is changed. Furthermore, in the configuration of the present application, one point on the sample is transmitted over the entire effective diameter of the light guide. Therefore, since the light emitted from one foot point is guided by approximately the same number of fibers as the light emitted from other points, local unevenness is eliminated except by the Cos fourth power law. Furthermore, the size of the pupil of the taking lens is measured F.
Although it is determined by the number, the amount of light, etc., by forming an image of this pupil on the light guide with a slight vertical axis, the east diameter of the light guide can be made small, and the size of the mirror, etc. can also be made smaller.

In addition, by providing an index projection optical system and an observation optical system, it is possible to accurately align the measurement point by matching the projected image, the measurement point can be easily confirmed in a normal environment, and a mirror for index projection can be used. Advantages include the ability to observe the state of the sample even during measurements when the temperature is high.

Furthermore, by fixing the illumination optical system inside the arm and separating it into the illumination section and the light transmission section, and connecting the two in the middle, there is no need to worry about the light guide becoming twisted or damaged when changing the illumination angle.
The advantage is that the overall length is short because there is no need to drag and move the light guide, the luminous intensity can be rotated over a range of 360 degrees, and the illumination light is natural light and cold light by passing through the fiber. have.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention. FIG. 2 is a perspective view of the sample stage according to the example. FIG. 3 and FIG. 4 are diagrams for explaining a conventional example. In the figure, 2...taking lens, 3...relay lens, 4...pinhole plate,
5... Concave lens, 7... Light guide, 8...
・... Visibility correction filter, 9... Light receiver, 1
0...ND filter group. Medicine' map 2nd figure 3'2 4th foot

Claims (1)

[Claims] 1. A light source for a sample illumination optical system that illuminates a sample in a special environment, an observation optical system that observes the sample, a taking lens that faces the sample, and a pinhole that forms an image of the sample with respect to the taking lens. a relay lens that images the pupil of the taking lens onto an end surface of a light guide in a special environment; the light guide having an output end near a light receiver outside the special environment; a concave lens having a post-measurement focal point at the imaging position that allows the light beam to enter at a gentle inclination angle at the periphery; and an optical path changing means that is provided between the pinhole plate and the light guide in the optical path and forms an optical path different from the measurement optical path. and projecting a measurement standard index that illuminates the sample with light of a different color from the illumination light of the light source of the sample illumination optical system through the optical path changing means and the pinhole plate when using the observation optical system. A luminance measuring device characterized by having an optical light source.