JPH0658325B2 - Lateral light transmission measuring instrument - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lateral light transmittance measuring device for measuring the lateral light transmittance of an object to be measured. It is widely used for aesthetic evaluation of skin.

[Conventional technology]

The light reflection on the surface of a car body or furniture is measured for the quality evaluation of the paint. In addition, when evaluating a special coating effect, its reflection spectrum and absorption spectrum are also evaluated.

FIG. 13 is a diagram showing an example of a conventional evaluation method. In the figure, the white light or the monochromatic light emitted from the light source 91 is applied to the base 92 and the coating portion 93 formed on the surface thereof. Then, the light reflected, transmitted, or refracted by this is incident on the photodetector 95 via the condenser lens 94 and sent as a detection signal to an evaluation device (not shown).

Here, the light detected by the photodetector 95 is the base 9
In addition to the light reflected by the surface of No. 2 or the surface of the coating part 93 (shown by the solid line and the dashed line in FIG. 13), the coating part 93
Light (illustrated by a dotted line in the figure) scattered within the interior of the paint, and light (illustrated by a chain double-dashed line in the figure) after being reflected by the substrate 92 and scattered inside the coating portion 93 are included. .

[Problems to be Solved by the Invention]

As described above, the light from the coated object includes scattered light as well as reflected light, but conventionally, this detection is collectively performed. Therefore, it is difficult to specially evaluate the scattered light and the like in the coated part.

However, the quality evaluation of the appearance of the object (evaluation of aesthetic quality)
In the above, the evaluation of the scattered light is extremely important.
For example, when a very small spot light is applied to the surface of the object, the reflected light becomes a very small spot light when there is no scattering by the coating portion as described above. In contrast,
When the surface of the object is coated to cause scattering, the scattered light spreads (bleeds) so as to surround the spot of the reflected light. This greatly affects the appearance quality of the object surface.

Therefore, it is an object of the present invention to provide a lateral light transmission measuring device capable of accurately evaluating the appearance quality of an object surface.

[Means for Solving the Problems]

The present invention relates to a lateral light transmittance measuring device for measuring lateral light transmittance on a flat surface of an object to be measured, which transmits a light source and light from the light source and emits the light toward the object to be measured. At least one emitting optical fiber, at least one incident optical fiber that receives and transmits light from the object to be measured, a photodetector that detects the light from the incident optical fiber, and A holding member for integrally holding the outgoing optical fiber and the incoming optical fiber so that the outgoing end face of the outgoing optical fiber and the incoming end face of the incoming optical fiber are arranged on a substantially same plane with a predetermined gap. And a proximal end held by this holding member, and a substantially tubular elasticity whose tip extends from the plane including the emission end face of the emission optical fiber and the incidence end face of the incidence optical fiber to the light emission side of the emission optical fiber. Composed of body, measured Characterized in that it comprises a shielding member for shielding entrance of external light into the object of the measurement region.

Here, the incident optical fiber is configured by a plurality of optical fibers provided with an incident end face in a predetermined positional relationship, a photodetector is provided for each of the plurality of optical fibers forming the incident optical fiber, and, You may make it further provide the comparison means which compares the light amount detected for each photodetector mutually. Further, a means for switching the optical paths from the plurality of optical fibers may be provided on the front surface of the photodetector, and the light quantity of the switched light may be compared by the comparison means.

[Action]

According to the configuration of the present invention, the measurement light from the emission optical fiber is transmitted laterally in the coated portion of the object surface and is incident on the incidence optical fiber as transmission detection light.

Here, the emission end face of the emission optical fiber and the incidence end face of the incidence optical fiber are sufficiently small in size, and the distance between them is set to a predetermined value. Further, since the tip of the shielding member made of a substantially tubular elastic body is in close contact with the object surface, the measurement area on the object surface is shielded from external light. Therefore, it is possible to accurately detect the transmitted light in the lateral direction.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the configuration of the first embodiment. The same figure (a)
Is a side view in which a part thereof is crushed, and FIG. 6B is a front view of a tip portion (probe portion). The emitting optical fiber 1 for emitting the measurement light is composed of a glass fiber 1a consisting of a central core and an outer cladding, and an outer coating layer 1b, which is provided with a protective coating 1c such as nylon. Has been done. The incident optical fiber 2 for entering the transmitted detection light also has a glass fiber 2a including a core at the center and an outer cladding,
It is composed of this outer coating layer 2b, which is provided with a protective coating 2c. This output optical fiber 1
The tip end of the incident optical fiber 2 is housed in the holding case 3 and is adjacent to each other. A light source 4 including a light emitting diode (LUD) or the like is connected to the other end of the emitting optical fiber 1, and a light including a photomultiplier tube or a photodiode (PD) is connected to the other end of the incident optical fiber 2. The detector 5 is connected.

Here, in order to prevent crosstalk between the output optical fiber 1 and the input optical fiber 2, resin that does not cause reflection or transmission is used as the coating layers 1b and 2b, or separately in the holding case 3. It is desirable to intervene. Further, it is desirable that the end faces of the optical fibers 1 and 2 are mirror-polished so as to have good adhesion with an object. Furthermore, in order to prevent external light from interfering with the measurement, a cover 7 made of a substantially tubular elastic body such as rubber for shielding external light is attached to the tip of the probe unit.

Next, the operation of the first embodiment will be described with reference to FIG.

When evaluating the quality of the surface of the object, the holding case 3 is operated on the surface of the coating portion 93 provided on the base 92 to bring the end faces of the emitting optical fiber 1 and the incident optical fiber 2 into contact with each other.
Then, the measurement light from the light source 4 enters the emitting optical fiber 1. This incident light (measurement light) passes through the core of the glass fiber 1a and enters the coating portion 93 from the emission end face, and, for example,
The glass fiber 2a of the incident optical fiber 2 passes through the paths shown by the dotted line, the one-dot chain line and the two-dot chain line in FIG.
It is incident on the core inside. The light thus entered is sent to the photodetector 5 as transmission detection light, converted into a transmission light signal as shown in FIG. 1, and sent to an evaluation device (not shown).

Here, the outgoing optical fiber 1 and the incoming optical fiber 2
The diameters of the glass fibers 1a and 2a constituting the above can be set to several tens to several hundreds of μm, so that the spot diameter of the incident light (measurement light) and the detection range of the emitted light (transmission detection light) can be made sufficiently small. Further, since the center distance between the exit end surface formed by the core of the glass fiber 1a and the entrance end surface formed by the core of the glass fiber 2a can be set to a constant value by the outer diameter value of the exit optical fiber 1 and the entrance optical fiber 2,
It is possible to quantitatively grasp the light transmission distance. For this reason, the spread (bleeding) of the light when the spot light is irradiated can be accurately detected, so that the scattering of the light in the coating portion 93 can be accurately detected. Further, since the outside light is blocked by the cover 7, the measurement result does not depend on the measurement environment. Furthermore, since the component reflected on the surface of the coating portion 93 does not enter the core 2a of the incident optical fiber 2,
The measurement result does not depend on the surface condition of the coating part 93.

Next, a modification of the first embodiment will be described with reference to FIGS. 3 and 4.

FIG. 3 is a sectional view of the first modification. In this case,
The holding case 31 includes not only the output optical fiber 1 and the input optical fiber 2 but also the LEDs 41 and L as a light source.
ED driving circuit 42, photomultiplier tube (P
The MT) 51 and the power supply bleeder 100 are also housed inside. A power input terminal 101 and an output terminal 102 are provided at the rear end of the holding case 31. FIG. 4 is a configuration diagram of the second modified example. In this case, unlike the first modified example, the light source 4 has the holding case 32.
It is provided outside of. Then, the PTM 51 and the power preloader 100 are connected via the socket 103.

In any of the above modifications, the output optical fiber 1 and the input optical fiber 2 are held at the tips (probe portions) of the holding cases 31 and 32 as shown in FIG. 1 (b). Therefore, the same effect as that described with reference to FIG. 2 is achieved. Furthermore, since the PMT51 is used as a photodetector, it can be applied when the light emission amount of the light source is small or the transmitted light is weak, and not only the detection sensitivity can be remarkably improved, but also the configuration is compact and the operability is excellent. There is.

Next, a second embodiment will be described.

FIG. 5 is a perspective view showing the structure of the main part (probe part). As shown in the figure, in this embodiment, the incident optical fiber 2 is composed of four optical fibers 21 to 24, which are arranged linearly with the outgoing optical fiber 2. The overall construction of the second embodiment is as shown in FIG. A light emitting element 43 is connected to the rear end of the emitting optical fiber 1,
The light emitting element 43 is driven by a light emitting element drive circuit 44. Photodetectors 5 _{1 to} 5 ₄ are connected to the rear ends of the four optical fibers 21 to 24 forming the incident optical fiber 2, and the output signals (transmitted light signals) thereof are transmitted to the incident light amount comparison device 110. To be given.

Here, the arrangement of the optical fibers in the probe unit is the fifth
It is linear as shown. Then, the center distance a between the light emitting and incident end faces of each fiber is set to be constant by the outer diameter dimensions of the optical fibers 2, 11 to 14 and the resin composition 8 interposed therebetween. Therefore, the degree of lateral transmission of light entering the coating section 93 can be quantitatively observed in relation to the process distance.

Next, the operation of the second embodiment will be described.

First, in the measurement, the tip portion (probe portion) of the holding case 3 is brought into contact with the coating portion 93 provided on the base 92.
Then, when the light emitting element 43 is turned on, the measurement light LO is emitted from the core portion of the emission optical fiber 1 and enters the coating portion 93. The measurement light LO is scattered in the coating portion 93 or reflected by the surface of the base 92 and returns to the surface of the coating portion 93 again. Then, the transmitted detection lights LI _{1 to} LI ₄ are made incident on the respective optical fibers 21 to 24 constituting the incident optical fiber 2, and these are photoelectrically converted by the photodetectors 5 _{1 to} 5 ₄ , and the incident light amount as a transmitted light signal. It is input to the comparison device 110. The incident light quantity comparison device 110 compares the light quantity levels of the respective transmitted light signals and examines the pattern of the level change.
Then, the pattern is compared with a preset pattern to evaluate the appearance quality of the substrate 92 having the coating portion 93. For example, as shown in FIG. 7, when the pattern becomes like the solid line in the figure, the quality is judged to be "moist feeling", and when it becomes like the dotted line, it is judged to be "dry feeling".

FIG. 8 is a perspective view showing an essential part of a modified example of the second embodiment.

In this case, six incident optical fibers 21 to 26 are arranged around the incident optical fiber 2. Then, these tips are integrally held by the holding case 3. Using this probe, it is possible to quantitatively detect how the transmitted light differs depending on the direction.

Regarding the aspect of the arrangement of the optical fibers, FIGS.
The present invention is not limited to the example shown in the figure, and various modes are possible. Basically, the modes can be combined into four modes as shown in FIG. FIG. 3A shows a case where the transmission in only one direction is measured, and eight incident optical fibers 2 are also arranged in one direction with respect to the outgoing optical fiber 1. 2 (b) is the opposite of 2
When measuring the transmission in the directions, each of the six incident optical fibers 2 is linearly arranged in the opposite direction with respect to one outgoing optical fiber 1. FIG. 3C shows the case where the transmission in the x direction and the transmission in the direction are simultaneously measured, and 5 × 4 input optical fibers 2 are arranged in a cross shape with respect to one output optical fiber 1. Further, FIG. 3D shows a case where the transmission distribution is two-dimensionally measured, and a large number of incident optical fibers 2 are dispersed around one outgoing optical fiber 1.

Regarding the arrangement as shown in FIG. 9 (a), the present inventor
Experiments as shown in FIG. 11 and FIG. 11 were conducted.

FIG. 10 shows the constitution of the experimental system, and FIG. 11 shows the result. First, as shown in FIG. 11, the outer diameter is 10
Six 0 μm optical fibers were prepared, one was used as the output optical fiber 1, and the other five were used as the input optical fibers 21 to 25. Then, using the resin composition 8, the center interval is 200
Fix each fiber 21, 21 to 25 μm,
LED is used as a light source, and PMT is used as a photodetector.
Was used, and the output was adapted to be counted by a photo counter. The transmission detection lights from the incident optical fibers 21 to 25 are sequentially given to the PMT by switching the optical path from the fibers as shown by the arrow in the figure.
For ED), DC lighting was performed.

When the skin of a human face was examined as an object to be measured using the above experimental system, the measured values were as shown by the solid line in Fig. 11 for a moist face, and for a dry face. The measured values became like the dotted line.

The present invention is not limited to the above embodiment, and various modifications can be made.

For example, various materials such as those made of silicon dioxide or plastic can be used as the material of the optical fiber, and the dimensions of the optical fiber can be appropriately changed. As the light source, in addition to the LED, a semiconductor laser (LD), a tungsten (W) lamp, a mercury (Hg) lamp, a halogen lamp, or the like can be used. Further, the photodetector is not limited to the photodiode or PMT. Here, when it is desired to examine the spectral transmission characteristics using only the light of the specific wavelength, for example, a spectroscope or an optical filter may be used. FIG. 12 shows an example in which an optical filter 58 is provided on the front surface of the PMT 51.

For fixing the output optical fiber 1 and the input optical fiber 2 at the probe portion, a connecting agent made of a resin composition can be used as in the example, but an appropriate spacer is interposed between the optical fibers. As a result, it is possible to set a desired distance between the light emitting surface and the incident end surface. Further, a cover for shielding external light can be provided also in the probe portion shown in FIGS. 5 and 8 and the shape and material thereof can be changed appropriately.

〔The invention's effect〕

As described above in detail, in the present invention, the measurement light from the emission optical fiber is transmitted laterally through the inside of the coating portion of the object surface and the like, and is incident on the incidence optical fiber as transmission detection light.
Here, the emission end face of the emission optical fiber and the incidence end face of the incidence optical fiber are sufficiently small in size, and the distance between them is set to a predetermined value. Further, since the tip of the shielding member made of a substantially tubular elastic body is in close contact with the object surface, the measurement area on the object surface is shielded from external light. Therefore, since it is possible to accurately detect the lateral transmitted light,
It is possible to accurately evaluate the aesthetic quality of the surface of an object.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of the first embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of the first embodiment, FIGS. 3 and 4
FIG. 5 is a diagram showing first and second modified examples of the first embodiment, FIG. 5 is a perspective view of a main portion of the second embodiment of the present invention, and FIG. 6 shows its entire structure. FIGS. 7 and 8 are views showing the unique action thereof, FIG. 8 is a perspective view of a main part of a modified example of the second embodiment, and FIG. 9 is a view showing a mode of arrangement of optical fibers. FIG. 10 is a block diagram of a device of an experimental system by the present inventor, FIG. 11 is a diagram showing a result of the experiment, FIG. 12 is a block diagram of a photodetector according to a modified example, and FIG. It is a figure which shows a technique. 1 ... Emitting optical fiber, 2, 21-26 ... Incident optical fiber, 3, 31, 32 ... Holding case, 4 ... Light source, 5 ... Photodetector, 7 ... Cover, 92 ... Base, 9
3 ... Painting department.

Claims (8)

[Claims] 1. A lateral light transmission measuring device for measuring lateral light transmittance on a flat surface of an object to be measured, which comprises transmitting a light source and light from the light source and directing the light to the object to be measured. At least one emitting optical fiber that emits light, at least one incident optical fiber that receives and transmits the light from the measured object, and a photodetector that detects the light from the incident optical fiber And, so that the emission end face of the emission optical fiber and the incidence end face of the incidence optical fiber are arranged on a substantially same plane with a predetermined gap, the emission optical fiber and the incidence optical fiber are A holding member that integrally holds the base end is held by the holding member, and from the plane including the emission end face of the emission optical fiber and the incidence end face of the incidence optical fiber, the tip thereof is the emission optical fiber. Light out An elastic body of generally tubular overhanging side, lateral light transmittance measuring device, characterized in that said and a shielding member for shielding the incident external light to the measurement areas of the object to be measured. 2. The lateral transmission measuring instrument according to claim 1, wherein the light source selectively emits light having a specific wavelength. 3. The lateral light transmission measuring device according to claim 1, wherein the photodetector has a filter for transmitting only light of a specific wavelength on a coupling end face with the incident optical fiber. . 4. The lateral light transmission measuring device according to claim 1, wherein the emitting optical fiber and the incident optical fiber are fixed to the holding member via a resin. 5. The incident optical fiber is a plurality of optical fibers whose incident end faces are arranged in a predetermined positional relationship, and the photodetector is provided for each of the plurality of optical fibers forming the incident optical fiber. The lateral light transmission measuring instrument according to claim 1, further comprising a comparing means which is provided and which compares the light amounts detected by the respective photodetectors with each other. 6. A switching means for switching an optical path is provided between the photodetector and the plurality of optical fibers, and the comparing means mutually compares the light amounts from the plurality of switched optical fibers. The lateral light transmission measuring device according to claim 5, wherein: 7. The lateral optical transmission measuring instrument according to claim 5, wherein the incident optical fiber comprises a plurality of optical fibers arranged so as to surround the outgoing optical fiber. . 8. The lateral optical transmission measuring instrument according to claim 5, wherein the incident optical fiber comprises a plurality of optical fibers arranged on the same straight line as the outgoing optical fiber. .