JP3464824B2 - Optical measuring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical measuring device for evaluating the visual angle dependence of the optical characteristics of a sample under diffuse illumination. 2. Description of the Related Art There is known a diffuse illumination / 0 ° measuring method in which a sample is measured from the vicinity of a vertex of an integrating sphere by irradiating a sample with perfect diffusion light by combining an integrating sphere and a light source. FIG. 7 shows a colorimeter which is an example of such an apparatus. The colorimeter is
This is an apparatus that includes the integrating sphere 2 and the light source 9 and performs color evaluation of the sample 3. The integrating sphere 2 is provided with a sample opening 22 at the lower portion, and the sample 3 is disposed in close contact with the sample opening 22, and θ on one radial line of the integrating sphere 2 with respect to the normal P of the sample 3. A measurement opening 5 having a lens 4 is provided at an angled position, and a light source opening 1 through which light from a light source 9 is guided via a light source fiber 8 is provided. Also,
By providing the opening 6 at a position symmetrical to the measurement opening 5 with respect to the normal, measurement can be performed in which the specular reflection component from the sample 3 has been removed.
Further, when a diffusion plate is attached to the opening 6, measurement including a specular reflection component can be performed. However, as is the above colorimeter is a good device in that illuminating the sample by complete diffusion light, the measurement direction is recommended Ri by the JIS standard Z8722
Is fixed from the law line angle within 10 °, it was not possible to evaluate the viewing angle dependence of characteristics of the sample under diffuse illumination. Therefore, as an apparatus which improves this point, as shown in FIGS. 8 and 9, a hemispherical integrating sphere 7 in which light from a light source 9 is guided through a plurality of light source fibers 8 is used. A slit 12 for measurement is provided along two radial lines, and an optical system 23 that can move along the slit 12 while maintaining a constant distance from the sample 3 is disposed in the slit 12. 3, the other end is connected to the detector 11 via the measuring fiber 10,
An optical measuring device that detects the optical characteristics of the sample 3 in order to evaluate the viewing angle dependence of the sample 3 is known. Also, since the slit 12 is provided over a half circumference of the integrating sphere 2,
Measurement including the specular reflection component of the sample 3 can be performed. Further, when the slit 12 is provided over substantially the entire circumference of the integrating sphere 2, measurement without the specular reflection component can be performed. The above-described optical measuring device can detect the optical characteristics of the sample in order to evaluate the visual angle dependence of the sample, but the illumination inside the integrating sphere is made up of a hemisphere. Since it is performed by the integrating sphere, the illumination light does not become completely diffused light. Therefore, the intensity of the illumination light at the position of the sample has directionality, and the optical characteristics of the sample depend on the number of optical fibers, the exit angle from the optical fibers to the integrating sphere, the spread angle of light at this time, and the like. There was a point. When a spherical integrating sphere is used for the above-mentioned optical measuring device, a completely diffused light can be obtained inside the integrating sphere, but since the optical system is arranged on the surface of the integrating sphere, the detection position of the optical system is determined. When the distance is changed, the distance between the sample and the optical system changes, and it is difficult to obtain a uniform photometric intensity. Therefore,
The present invention has been made in view of the above problems,
It is an object of the present invention to provide an optical measuring device that detects uniform photometric intensity of optical characteristics of a sample under illumination of completely diffused light. Means for Solving the Problems The invention according to claim 1 is:
A diffuse illumination system for illuminating a sample, comprising a spherical integrating sphere having a measurement opening on its peripheral surface and a light source, and an optical system having one end facing the sample and the other end connected to a detector. In the optical measuring device for measuring the optical characteristics of the sample, a plurality of the measurement openings are provided so as to have different distances from the sample, and the optical system is attached to any of the plurality of measurement openings. An optical measuring device capable of detecting the photometric intensity of the sample, wherein the optical system is a laser.
It consists of a lens-type luminance meter.
The sample slides in the optical axis direction, and the measurement opening and the sample
It can be set to a position corresponding to the distance between An optical system composed of a lens type luminance meter is attached to the measurement opening of the spherical integrating sphere, or the spherical integrating sphere is measured. One end from the opening is introduced into the inside of the integrating sphere, the optical system is slidably and detachably inserted into the measuring opening, or each end and the sample are inserted from a plurality of measuring openings of the spherical integrating sphere. Each end is introduced into the integrating sphere from each measurement opening so that the distance between them becomes a predetermined distance, and the optical system is inserted and fixed in each measurement opening, so the detection position of the reflected light of the sample changes. However, the photometric intensity of the reflected light is detected uniformly. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 2 denotes an integrating sphere. The inner surface of the integrating sphere 2 is coated with a white paint such as barium sulfate which has a high diffuse reflectance and does not absorb light. The integrating sphere 2 is provided with a sample opening 22, a plurality of measurement openings 13 to 17 provided along one radial line of the integrating sphere 2, and the light source opening 1. Further, according to JIS standard Z8722, the sum of these opening areas is equal to the integrating sphere 2
Is set so as to be 10% or less with respect to the sum of the inner surfaces. The sample opening 22 is provided below the integrating sphere 2, and the sample 3 is arranged so as to close the sample opening 22. A light source 9 is connected to the light source opening 1 via a light source fiber 8. Inside the integrating sphere 2, the light source opening 1 is placed closer to the sample opening 22 than the light source opening 1.
A baffle 21 for preventing light emitted from the light source from directly entering the sample 3 is provided. On the entire surface of baffle 21,
The same paint as the inner surface of the integrating sphere 2 is applied. Also,
If there is a possibility that the light incident on the integrating sphere 2 may directly enter the measurement openings 13 to 17, the baffle 21 is arranged by changing the position and the shape of the baffle 21. The measurement opening 13 is provided at a vertex of the integrating sphere 2, that is, at a position where the normal N, which is the center of the sample opening 22 and stands on the sample 3, intersects the surface of the integrating sphere 2. . The measurement opening 14 is provided with θ = 15 ° with respect to the normal line N. The measurement openings 15, 16, 17 are also
Like the measurement opening 14, they are provided on one radial line of the integrating sphere 2 at an angle of θ = 15 °. Each of the measurement openings 13, 15, 16, 1 is provided in the measurement opening 14.
A detachable lens-type luminance meter 18 is attached to the lens 7.
The lens-type luminance meter 18 has one end attached to the measurement opening 14 facing the sample, and the other end connected to the detector 20 via the measurement fiber 19. 2 and 3, a lens type luminance meter 18 is used.
Will be described in detail. As shown in FIG. 2, inside a lens barrel 27 whose inner surface is dyed black to reduce unnecessary reflected light, a luminosity correction filter 28 is slid in the optical axis direction in order from one end facing the sample 3. A movable lens 29, movable diaphragms 30 and 31, and a diffuse translucent plate 32 are arranged, and a detector 20
The other end to which (FIG. 1) is connected is a measuring fiber 19.
A fiber fixing connector 33 for fixing the optical fiber is provided. Scales 13a to 17a for adjusting the position of the movable lens 29 when detecting the optical characteristics of the sample 3 by attaching the lens type luminance meter 18 to each of the measurement openings 13 to 17 are provided on the outer peripheral surface of the lens barrel 27. It is marked. In FIG. 1, since a lens type luminance meter 18 is mounted on the measurement opening 14,
The position of the movable lens 29 is adjusted to the scale 14a.
The movement of the movable lens 29 in the lens barrel 27 is performed by a lens moving mechanism usually employed in optical equipment. In FIG. 3, a diaphragm 30 is provided with a movable lens 29.
Is arranged on the surface on which the image of the sample 3 is formed in the operation range of. First, when the sample 3 and the movable lens 29 are sufficiently separated from each other, the distance between the movable lens 29 at the position where the image of the sample 3 is formed on the surface of the diaphragm 30 and the image forming plane is determined by the focal length of the movable lens 29. l1. At this time, the solid angle determined by the size of the movable lens 29 and the distance 11 is α. The position of the movable lens 29 at this time is defined as position A. Next, when the sample 3 and the movable lens 29 are not sufficiently separated from each other, if an image of the sample 3 is to be formed on the surface of the diaphragm 30, the position of the movable lens 29 is more than that of the position A. Moving to the third side, the movable lens 29 moves to the position B. At this time, the distance between the movable lens 29 and the imaging plane is l2. The solid angle determined by the size of the movable lens 29 and the distance l2 is β. Accordingly, as the distance between the lens-type luminance meter 18 and the sample 3 becomes shorter, the distance between the movable lens 29 and the image forming plane of the sample 3 becomes longer, and the solid angle β always becomes smaller than the solid angle α. The solid angle determined by the distance between the stop 31 and the image plane and the size of the stop 31 is γ. FIG. 3 shows a case where the solid angle β = the solid angle γ, and the distance between the movable lens 29 and the sample 3 at this time is a distance L. When the solid angle β is larger than the solid angle γ, the light passing through the diaphragm 30 always reaches the diaphragm 31 at a solid angle larger than the solid angle γ. The amount of light passing through the stop 31 is determined by the size of the stop 31 and is always constant. That is, when a relationship is established in which the solid angle β is always larger than the solid angle γ and the solid angle α is larger than the solid angle β, the amount of light passing through the diaphragm 31 is constant. In other words, when the distance between the movable lens 29 and the sample 3 is greater than the distance L, the photometric intensity of the sample 3 is always uniform regardless of the distance. Can be detected. Therefore, the lens type luminance meter 18 is always arranged at a position where the distance between the movable lens 29 and the sample 3 is larger than the distance L. Next, the detection of the optical characteristics of the reflected light from the sample 3 for evaluating the viewing angle dependence of the sample 3 will be described. The light from the light source 9 reaches the light source opening 1 via the light source fiber 8, exits from the light source opening 1 to the inside of the integrating sphere 2, is diffused and reflected by the inner surface of the integrating sphere 2, and becomes completely diffused light. The surface of the sample 3 is illuminated. The light reflected on the surface of the sample 3 enters one end of the lens-type luminance meter 18. The light intensity of the reflected light from the surface of the sample 3 is made uniform by the lens type luminance meter 18 and transmitted to the detector 20 via the measuring fiber 19. Therefore, the optical characteristics of the reflected light are detected by the detector 20. The lens-type luminance meter 18 is detached from the measurement aperture 14, the movable lens 29 is positioned at the position corresponding to the scale 15a, and the lens-type luminance meter 18 is mounted on the measurement aperture 15, and the same as described above. The optical characteristics of the reflected light are detected.
At this time, when the distance between the lens type luminance meter 18 and the sample 3 changes, the photometric intensity of the reflected light also changes. However, the photometric intensity is made uniform by the lens type luminance meter 18, and And transmitted to the detector 20. Similarly, when the reflected light is detected from another measurement aperture, the optical characteristics of the reflected light having a uniform photometric intensity can be detected. In an optical measuring device as shown in FIG.
Using a photomultiplier as a detector, using a standard white plate as a sample, and detecting the brightness of the sample at each measurement aperture,
Similar values were detected in all the measurement openings, and the characteristics of the standard white plate were reproduced. Further, the reflected light may be detected by disposing the detector 20 directly at the position of the diaphragm 31. FIG. 4 shows another embodiment. In this figure, the integrating sphere 2 is the same as the integrating sphere 2 described with reference to FIG. 1 except for the measurement openings 53 to 57, so that the same reference numerals are given, and the description thereof will be omitted, and different points will be described. The measurement opening 54 is formed so that the rod-shaped optical system 25 having a small diameter and a predetermined length is slidably and detachably inserted. The optical system 25 is formed of a rigid optical fiber, the surface of which is coated with the same paint as the inner surface of the integrating sphere 2 and is marked with scales 53a to 57a. When the optical system 25 is inserted into the measurement opening 54, the scale 54a indicates that the distance between the inner end of the optical system 25 introduced into the integrating sphere 2 and the sample 3 is r (the sample opening 22).
(A radius centered on the center of the measurement opening 54). Scale 53
a, 55a, 56a, and 57a are used for each measurement so that the distance between the inner end and the sample 3 becomes r when the optical system 25 is inserted into the other measurement openings 53, 55, 56, and 57. Opening 53
５７57 are marked respectively so as to coincide with the open ends. A detector 20 is connected to an outer end of the optical system 25 via a measuring fiber 19. The optical system 25 is extracted from the measurement opening 54, and the other measurement openings 53, 55, 5
6, 57 can be inserted. The light incident on the integrating sphere 2 is the same as that of the integrating sphere 2 described with reference to FIG.
The detection of the optical characteristics of the light reflected by the surface will be described. The reflected light incident from the inner end of the optical system 25 passes through the inside of the optical system 25 and is transmitted to the detector 20 via the measuring fiber 19, and the photometry at the position r from the surface of the sample 3 is performed by the detector 20. Intensity optical properties are detected. The optical system 25 is removed from the measurement opening 54, and the optical system 25 is inserted into the measurement opening 57 so that the scale 57a is aligned with the opening end of the measurement opening 57 as shown by a broken line. The optical characteristics of the reflected light are detected. In this case, the inner end of the optical system 25 is also positioned at a distance r from the surface of the sample 3, so that the photometric intensity at that position is the same as the above-described measured value, and the reflected light is measured under the same photometric intensity. Is detected. Therefore, no matter which measuring aperture the optical system is inserted into, the distance between the inner end of the optical system and the sample can be adjusted to a predetermined distance, and the optical characteristics of the reflected light can be adjusted with a uniform photometric intensity. Can be detected. FIG. 5 shows still another embodiment. In the figure, the integrating sphere 2 is the same as the integrating sphere 2 described in FIG. 4, and therefore, is denoted by the same reference numeral, description thereof will be omitted, and different points will be described. Bar-shaped probe optical fibers 39 to 43 having a small diameter and a predetermined length are inserted into and fixed to the measurement openings 53 to 57, respectively. The probe optical fibers 39 to 43 are made of optical fibers, and the surface thereof is coated with the same paint as the inner surface of the integrating sphere 2. The inner ends of the probe optical fibers 39 to 43 are introduced into the integrating sphere 2 so that the distance from the sample 3 is r (radius about the sample opening 22), and the illumination intensity is set inside the integrating sphere 2. Are arranged so that no direction dependency occurs. An optical fiber connector 46 is connected to the outer end of the probe optical fiber 40, and a photomultiplier 45 is connected via the light guide optical fiber 44. The optical fiber connectors 46 can be connected to the outer ends of the other probe optical fibers 39, 41, 42, and 43, respectively. The light incident on the integrating sphere 2 is the same as that of the integrating sphere 2 described with reference to FIG. Will be described. The reflected light incident from the inner end of the probe optical fiber 40 passes through the probe optical fiber 40 and is transmitted to the photomultiplier 45 via the light guide optical fiber 44. Therefore, the photomultiplier 45 detects the optical characteristic of the photometric intensity at a position at a distance r from the surface of the sample 3 in the measurement opening 54. The optical fiber connector 46 is detached from the outer end of the probe optical fiber 40 and connected to the outer end of the probe optical fiber 43 as shown by a broken line, and the optical characteristics of the reflected light are detected as described above. Since the inner end of the probe optical fiber 43 is also located at a distance r from the surface of the sample 3, the photometric intensity at that position is the same as the above-described photometric intensity at the inner end of the probe optical fiber 40,
The optical characteristics of the reflected light are detected under the same photometric intensity. Therefore, in any of the probe optical fibers, since the distance between the inner end of the probe optical fiber and the sample is fixed, the optical characteristics of the reflected light can be detected with a uniform photometric intensity. In the optical measuring apparatus as shown in FIG. 5, when the viewing angle dependency of the brightness of the sample was evaluated using a twisted nematic (TN) type liquid crystal element as the sample, the viewing angle dependency of visual observation under normal illumination was qualitatively determined. Was obtained. FIG. 6 shows another embodiment of the present invention. 4, the same members as those shown in FIG. 4 are denoted by the same reference numerals as those used in FIG. 4, and description thereof will be omitted.
As shown in FIG. 6, the integrating sphere 2 is provided with a slit-shaped measurement opening 60 substantially all around the one diameter line. The integrating sphere 2 is covered with a hemispherical guide member 70 having a radius d from a measurement point 72 which is the center of the sample opening 22. A guide slit 71 is provided in a line segment (meridian) of the guide member 70 where the plane including the measurement opening 60 and the guide member 70 intersect. An optical system holder 73 that holds the optical system 25 that moves along the measurement opening 60 is slidably provided in the guide slit 71. In addition,
The light source opening 1 and the baffle 21 are provided at positions that do not interfere with the measurement opening 60. The light incident on the integrating sphere 2 is the same as that described with reference to FIG. 1, and the description thereof will be omitted. The detection of the optical characteristics of the light reflected on the surface of the sample 3 will be described. When the photometric intensity of the reflected light of the sample 3 is detected at the position of the optical system 25 shown in FIG. 6, the optical characteristic of the photometric intensity at a position at a distance r from the surface of the sample 3 is detected. Optical system holder 7
Even if the position of the optical system 25 is moved by sliding the optical system 25 along the guide slit 71, the inner end of the optical system 25 is located at a distance r from the sample 3, so that the photometric intensity at that position is:
The intensity becomes the same as the photometric intensity detected at the position of the optical system 25 described above, and the optical characteristic of the reflected light is detected under the same photometric intensity. Therefore, even if the position of the optical system 25 is moved along the guide slit 71, the inner end of the optical system 25 and the sample 3
Can be maintained at a predetermined distance, so that the optical characteristics of the reflected light can be detected with a uniform photometric intensity. Further, the detection angle of the reflected light of the sample 3 can be continuously changed. In the optical measuring device shown in FIG.
By detecting the optical characteristics of the above, measurement without specular reflection components can be performed. In addition, when the measurement opening 60 is provided substantially half way along one radial line of the integrating sphere 2, measurement including the specular reflection component of the sample 3 can be performed. Also, in FIG. 1, the measurement openings 13 to 17 may be the measurement openings 60 shown in FIG. The optical system described above may be a combination of an optical fiber and a lens in addition to the lens type luminance meter and the rod-shaped optical fiber. Further, the connector may be an optical fiber connector with a collimator, an optical fiber connector with a lens system, or the like. Further, the optical system and the connector may be used in combination. As described above, according to the present invention,
Since the spherical integrating sphere is used, the sample can be illuminated with perfectly diffused light. Even if the detection position of the reflected light from the sample changes, the photometric intensity of the reflected light is detected uniformly by the lens-type luminance meter. Alternatively, the distance between the inner end of the optical system and the sample is maintained at a predetermined value, and the photometric intensity of the reflected light is detected uniformly .
It is possible to evaluate the viewing angle dependence characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an optical measuring device showing one embodiment of the present invention. FIG. 2 is a sectional view of the lens type luminance meter in FIG. FIG. 3 is an explanatory diagram of a lens type luminance meter. FIG. 4 is a cross-sectional view of an optical measurement device showing another embodiment of the present invention. FIG. 5 is a cross-sectional view of an optical measuring device showing still another embodiment of the present invention. FIG. 6 is a cross-sectional view of an optical measuring device in which a measuring opening of an integrating sphere has a slit shape. FIG. 7 is a sectional view of a conventional colorimeter. FIG. 8 is a schematic diagram of a conventional optical measurement device. FIG. 9 is a cross-sectional view of a conventional optical measurement device. [Description of Signs] 1 Aperture for light source 2, 7 Integrating sphere 3 Sample 4 Lens 6 Aperture 8 Fiber for light source 9 Light source 10, 19 Fiber for measurement 11, 20 Detector 18 Lens type luminance meter 13 to 17 as optical system, 53-57,60 Measurement aperture 22 Sample aperture 23 Optical system 25,39-43 Optical fiber as optical system

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-305224 (JP, A) JP-A-6-43030 (JP, A) JP-A-63-175744 (JP, A) 165823 (JP, U) Shokai Sho 59-4450 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/00-21/01 G01N 21/17-21/61 G01J 3/00-3/52 PATOLIS

Claims (1)

(57) [Claims] [Claim 1] A spherical shape having a measurement opening on its peripheral surface
An optical measuring device comprising an integrating sphere and a light source for illuminating a sample, and an optical system having one end facing the sample and the other end connected to a detector for measuring the optical characteristics of the sample. In the above, a plurality of the measurement openings are provided so that the distance from the sample is different from each other, and the optical system is attached to any of the plurality of measurement openings, and the photometric intensity of the sample can be detected. An optical measurement device, wherein the optical system is constituted by a lens-type luminance meter,
Lens for the above measurement slides in the optical axis direction.
An optical measurement device , which can be set at a position corresponding to a distance between an opening and the sample .