JP3095571B2 - Gloss measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glossiness measuring device, and more particularly to a glossiness measuring device capable of accurately measuring glossiness regardless of the curvature of an object surface.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a glossiness measuring apparatus for quantitatively measuring the glossiness of a painted surface or the like by using a light-dark pattern having light-dark portions having different light transmittances (Japanese Patent Publication No. Sho 5).
No. 7-59490).

[0003] In accordance gloss measurement device has a light passing through the light-dark pattern and dark pattern having at least one pair bright portion and a dark portion and a lens system for irradiating the surface to be measured. At a position where the light reflected from the surface to be measured can be received, a photoelectric conversion element that outputs an electric signal according to the intensity of the incident light is provided. A pinhole is provided on the incident side of the photoelectric conversion element, and the pinhole is provided at a position on an image plane on which the pattern is formed by the lens system. When measuring the glossiness, the control unit moves the light / dark pattern in a direction crossing the optical axis connecting the light source and the photoelectric conversion element. Therefore,
The light-dark boundary portion of the light-dark pattern image passes over the pinhole. As a result, the light intensity of the projected image of the light and dark pattern passing over the pinhole changes, and an electric signal corresponding to the change in the light intensity is output from the photoelectric conversion element.

Here, the blur at the boundary between light and dark in the light and dark pattern image formed through the surface to be measured, that is, the relationship between the sharpness and the glossiness of the surface to be measured is determined when the surface to be measured has low gloss. It has been confirmed by an experiment that the blur at the boundary is large and the blur at the light-dark boundary is small when the gloss is high. Further, the tangent gradient of a curve that changes from a dark portion to a bright portion of the light intensity obtained by moving the light-dark pattern has a correlation with the glossy sensory value (visibility) of the measured surface, which is statistically obtained. It has also been experimentally confirmed that the maximum value of the tangent gradient of, that is, the maximum value of the differential value of the light intensity corresponds to the glossiness of the surface to be measured.

Therefore, the light intensity of the light-dark pattern image accompanying the movement of the light-dark boundary portion is detected based on the electric signal, and the light intensity curve obtained by moving the light-dark pattern gives a maximum value of the differential value of the light intensity. The value is determined and the gloss is determined.

Since the maximum value of the differential value of the light intensity is the gloss, the amount of change in the light intensity with respect to the unit change amount of the position of the light-dark pattern, that is, the maximum value of the change amount of the light intensity is also considered as the gloss. Degree is required.

[0007]

However, the measured
If the surface has a curvature, the following problem occurs. sand
That is, as shown in FIG.
When the pattern image position is F ₀And the surface to be measured
Is convex, the reflected light from the surface to be measured diverges.
F₀To F₁The imaging position of the light and dark pattern changes like
Resulting in. On the other hand, when the surface to be measured is concave, FIG.
As shown, the reflected light from the surface to be measured converges,₀
To F_TwoThe image position of the light and dark pattern changes like
I will.

As described above, the image of the light and dark pattern is out of focus on the photoelectric conversion element, and the light intensity changes.
As a result, the amount of change in light intensity obtained by moving the light-dark pattern changes. In the conventional gloss meter, since the maximum value of the change amount is calculated as the gloss, as shown in FIG. 9, for example, when the measured surface is convex when compared with the flat gloss, the curvature is large. The lower the gloss, the greater the decrease in gloss. That is, if the surface to be measured is a curved surface, even if the glossiness is visually the same as the glossiness of the plane, the glossiness different from the glossiness of the plane is measured due to the curvature. The problem arises.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a glossiness measuring apparatus capable of accurately measuring glossiness regardless of the curvature of a surface to be measured.

[0010]

Means for Solving the Problems The present invention has been made to achieve the above-mentioned object, and a gloss measuring apparatus is provided.
A light source, a pattern including at least one pair of portions having different light transmittances, a projection unit configured to project light radiated by the light source and passing through the pattern onto a surface to be measured, and to form an image of the pattern; and a projection unit. A photoelectric conversion unit that is disposed at a position where the image of the pattern is formed and converts the light intensity of the reflected light from the surface to be measured into an electric signal, and the light of the light incident on the pattern Pattern moving means for moving the pattern in a direction orthogonal to the axis and in which the light transmittance of the pattern changes, light intensity reflected on the surface to be measured based on an electric signal input from the photoelectric conversion means The maximum value of the amount of change or differential value is calculated, and the maximum value is stored in advance according to the curvature of the surface to be measured.
And a calculating means for correcting with the correction value set .

[0011]

The gloss measuring device of the present invention has a light source. The light source illuminates the pattern, and the pattern includes at least one pair of portions having different light transmittances.
The pattern moving means moves the pattern in a direction perpendicular to an optical axis of light incident on the pattern and in a direction in which light transmittance of the pattern changes. The projection unit projects the light that has passed through the pattern onto the surface to be measured and forms an image of the pattern. A photoelectric conversion unit is provided at an image forming position of the projection unit. The photoelectric conversion unit converts the light intensity of the reflected light from the surface to be measured into an electric signal. The calculating means obtains the maximum value of the change amount or the differential value of the light intensity based on the electric signal, and stores the maximum value in advance according to the curvature of the surface to be measured.
The correction value is used.

As described above, the amount of change in the light intensity or the maximum value of the differential value of the light intensity obtained by moving the light-dark pattern changing from the dark part to the light part is corrected according to the curvature of the surface to be measured. Therefore, the glossiness obtained is accurate regardless of the curvature of the surface to be measured.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 5 is a schematic view showing a first embodiment of the glossiness measuring device 10 of the present invention.

As shown in FIG. 5, the optical section of the gloss measuring device 10 of this embodiment is housed in a housing 28. The glossiness measuring device 10 includes a light source 12 connected to a power supply (not shown), and a condenser lens 14 that collects light emitted from the light source 12 is disposed near the light source 12. Note that a light emitting element such as a tungsten lamp, a halogen lamp, or an LED can be used as the light source 12.
On the exit side of the condenser lens 14, a light-dark pattern 16,
The projection lens 18 and the mirror 20 are arranged in order. As shown in FIG. 10, the light-dark pattern 16 is formed by depositing aluminum or the like on one portion of one surface of glass whose both surfaces are polished, thereby forming a pair of light-dark portions having different transmittances between the deposition surface 46 and the transmission surface. Has a part. The light-dark pattern 16 is
It is attached to a slide table (not shown) so as to be movable in a direction perpendicular to the optical axis. A pulse motor 26 is attached to this sliding table.
In accordance with the drive of No. 6, the sliding table moves. That is, the light / dark pattern 16 is movable with the driving of the pulse motor 26. The light-dark pattern 16 is
The slide table is attached so as to move in a direction in which the transmittance changes, and the slide table is attached so as to move in a direction substantially orthogonal to the direction of light emitted from the condenser lens. A limit switch 38 is attached to each end of the sliding table in the moving axis direction so as not to move beyond the movable range, that is, to prevent the pulse motor 26 from being driven beyond the movable range. Have been. This limit switch 3
8 is connected to the control circuit. Condenser lens 14
Light emitted from the projection lens 1
8. The light irradiates the mirror 20 and the light reflected by the mirror 20 irradiates the surface 36 to be measured. A predetermined distance is maintained between the measured surface 36 and the glossiness measuring device 10 by a contact (attachment) 74.

On the reflection side of the surface 36 to be measured, a photoelectric conversion element 24 having a pinhole 22 having a hole of a predetermined diameter is formed.
Are arranged. Pinhole 22 of photoelectric conversion element 24
Is disposed at the image forming position of the projection lens 18. The reflected light from the measured surface 36 passes through the pinhole 22 and irradiates the photoelectric conversion element 24. Also, the photoelectric conversion element 24
Are connected to the control circuit 32. The control circuit 32
The pulse motor driver 30 is connected to a display device 34 for displaying glossiness and the pulse motor driver 30.
Is connected to the pulse motor 26.

The control circuit 32, as shown in FIG.
U (central processing unit) 52, ROM (read only memory) 54, RAM (random access memory) 5
6. It has a correction value ROM 55 in which correction values for correcting glossiness in accordance with the curvature are stored. CPU5
2. The ROM 54, the RAM 56, and the correction value ROM 55 are mutually connected to the data command bus line 50 and the like so that data and commands can be input and output between them. On the other hand, the photoelectric conversion element 24 is arranged at a position where the light passing through the pinhole 22 can be received and outputs a voltage corresponding to the intensity of the received light. This photoelectric conversion element 2
4 is connected to an amplifier (AMP) 64 for amplifying an input voltage with a predetermined gain, and the AMP 64 is connected to an ADC (analog-digital converter) 60 via a filter 62 for removing a noise component. ing. ADC60
Is connected to the data command bus line 50,
An analog signal proportional to the light intensity applied to the photoelectric conversion element 24 is converted into a digital signal. The display device 34 is connected to the data command bus line 50,
The obtained gloss value is displayed on the display device 34. A pulse motor driver 30 for transmitting a drive signal to the pulse motor 26 is connected to the data command bus line 50. The pulse motor driver 30 corresponds to the rotation amount and the rotation direction of the input pulse motor 26. The control signal is converted into a driving signal.

Next, the correction values stored in the correction value ROM 55 will be described in detail.

As described above, when the surface to be measured is a curved surface having a certain curvature, the reflected light from the surface to be measured diverges and converges as shown in FIGS. The image position is not at the position of the photoelectric conversion element 24, and as a result, the image of the light and dark pattern 16 is out of focus. Therefore, FIG.
(A) As shown in FIG.
The light intensity of the image decreases. For this reason, as shown in FIG. 11B, the maximum value of the change amount of the light intensity is also reduced, and accordingly, the glossiness of the curved surface is different from the glossiness of the flat surface. Therefore, in order to measure the glossiness accurately, it is necessary to correct the measured glossiness according to the curvature.

First, the curvature is obtained as follows. As shown in FIG.
The contact 74 for contacting a point is brought into contact with the surface to be measured, and the glossiness is measured. These three contacts 74 are arranged on the same circumference with a radius l. When the surface to be measured is a curved surface, the distance from the gloss measuring device 10 to the surface to be measured changes depending on the difference in curvature. For example, in the case the measured surface is convex curvature U _1, only gloss measurement apparatus distance h than the plane 10
Is approaching. Here, h and the curvature U (1 / R (R = radius of curvature)) are grasped from the following equation (1).

[0020]

U = 2h / (h ² + l ² ) Since the radius l of the circle where the three contacts 74 are arranged is a constant, the curvature of the surface to be measured is calculated when the distance h is known. /> is Ru.

Here, the light-dark pattern 16 moves and its
When the image of the if edge passes over the pinhole 22,
The change amount of the light intensity becomes maximum. Light / dark pattern at this time
The value of the position 16 is Hpi (where i = 1, 2, 3,...)
・ N). The surface to be measured has a curvature U₀(= 0) plane field
When the image of the light and dark pattern 16 passes over the pinhole,
The position Hp of the light-dark pattern 16 at which the change in intensity is maximum
₀Is A in FIG.₀Equivalent to a point. However, for example,
Measurement surface has curvature U₁In the case of the convex surface of
Position Hp₁Is A in FIG.₁Changes to the position corresponding to
You. This is because the light that has passed through the projection lens 18 has an incident angle a₀
Incident angle a₀Same reflection angle a as ₀Reflected by
Therefore, an image of the light and dark pattern 16 is formed on the photoelectric conversion element 24.
In order to perform the₀From A₁To
Because they have to be moved.

Therefore, the distance h and the position Hp _i of the light-dark pattern 16 have the following relationship:

[0023]

H = d · (Hp _i −Hp ₀ ) where d is a constant.

Here, the surface to be measured is a flat surface and the curvature U ₁
Assuming that the positions of the light and dark patterns 16 at which the change in the light intensity on the convex surface of the light-emitting element is the maximum are Hp ₀ and Hp ₁ , respectively, the relationship between these and the curvature is the following Expression ₃ from Expressions ₁ and 2.

[0025]

Hp ₁ −Hp ₀ ∝U _{1 Further} , if the position of the light / dark pattern 16 where the amount of change in light intensity on the concave surface of the surface to be measured has the maximum curvature U ₂ is Hp ₂ , the relationship with the curvature is In this case, the following equation 4 is obtained from the equations 1 and 2.

[0026]

Hp ₂ −Hp ₀ ∝U ₂ Here, since the position Hp ₀ of the light-dark pattern 16 in the case of a plane is constant, the position Hp _i of the light-dark pattern 16 corresponds to the curvature.

Because of the relationship of Equations (3) and (4), the position of the light-dark pattern 16 and the light intensity S of the reflected light when the light-dark pattern 16 moves and the image passes over the pinhole 22, and the light intensity thereof FIG. 11 shows the relationship between
become that way. When the measurement surface is a plane having a curvature U ₀ , the position Hp ₀ of the light-dark pattern 16 corresponds to A ₀ in FIG. 13, and the relationship between the light intensity S and the change amount T of the light intensity is shown in FIG.
1 is a solid line. In contrast, when the measurement surface is a convex curvature U _1, position Hp ₁ light-dark pattern 16 is A ₁ in FIG. 13
And the relationship between the light intensity S and the change amount T of the light intensity is indicated by a dotted line in FIG.

[0028] From the above, when correcting the measured glossiness curvature, it is possible to use the position Hp _i light-dark pattern 16 by substituting the curvature. In addition, the light and dark pattern 1
The position Hpi at 6 is measured from the number of pulses of the pulse motor 26.

Further, as shown in FIG. 14, a correction value for correcting the curvature according to the curvature needs to be a value obtained by subtracting the glossiness of the curved surface from the glossiness of the flat surface. The correction value is stored in the ROM 55. That is, first,
The glossiness of a reference plane and the glossiness of various curved surfaces having visually the same glossiness as the plane are measured in advance. Then, the value of the gloss of the curved surface is subtracted from the value of the gloss of the plane. This subtraction value is used as a correction value Δ as shown in FIG.
GT _i (where i = 1, 2, 3,... N) and the correction value ROM 5 corresponding to the position Hp _i of the light and dark pattern 16
5 is stored.

The operation of this embodiment will be described below.
When a measurement start switch (not shown) of the glossiness measuring device 10 used in the present embodiment is turned on, a control signal is sent to the pulse motor driver 30 in accordance with a command from the CPU 52, and
The rotation of the pulse motor 26 is controlled. Pulse motor 2
When 6 rotates, the rotation of the pulse motor 26 is converted into linear motion of the sliding table by a conversion mechanism (not shown) represented by a rack and pinion or the like. Therefore, the predetermined rotation of the pulse motor 26 is converted into a predetermined moving amount of the sliding table. For this reason, the light-dark pattern 16 fixed to the sliding table is perpendicular to the optical axis of the projection lens 18 as indicated by the arrow A.
Move in the direction. When the light-dark pattern 16 moves, the boundary between the light part and the dark part of the light-dark pattern 16 formed by the projection lens 18 via the measured surface 36 moves on the front surface of the photoelectric conversion element 24. The photoelectric conversion element 24 converts the signal into an electric signal corresponding to the intensity of light passing through the pinhole 22. The CPU 52 obtains the gloss according to the routine described below.

Next, the control of the glossiness measurement in the control circuit 32 of this embodiment will be described with reference to the drawings.

[0032] Figure 1 shows a main routine of the gloss measurement in this embodiment, initialization is performed in step 100, the processing number n is 1 is set to the maximum value T ₀ of the light intensity variation Is set to 0. Further, the movement amount p of the light and dark pattern 16 is taken in. On the other hand, one of the limit switches 38 is set so that the sliding table returns to the initial state.
Is turned on until the pulse motor 26 is turned on. When the initialization is completed, the process proceeds to step 104,
Then, the light intensity Sn is captured by the photoelectric conversion element 24, and the process proceeds to step 106. At step 106, the number of processes is determined. If the process is the first time, the process proceeds to step 116, and if not, the process proceeds to step 108. Step 108
Then, the maximum value Tn of the detected light intensity variation is calculated, and the routine proceeds to step 110. In step 110, the magnitude of the maximum value Tn of the change in light intensity calculated in step 108 is compared with the previously calculated maximum value Tn-1, and if the maximum value in the current processing state is larger than the previous maximum value. In step 112, the maximum value Tn of the amount of change in light intensity in the current process is stored as the maximum value in Tmax, and
Proceed to 13. In step 113, a value obtained by multiplying the current number of measurements n by the movement amount p is stored as the position Hpi of the light-dark pattern 16, and the process proceeds to step 114. Step 1
In 10, if the maximum value of the light intensity change amount in the current processing state is smaller than the previous maximum value, the process proceeds to step 114 while holding the previously calculated maximum value Tn −1 as the maximum value. As described above, the maximum value Tmax of the amount of change in light intensity in the boundary area between the light and dark portions is held. In step 114, the state of the other limit switch 38 on the sliding table is determined. If the light / dark pattern 16 is still movable, the limit switch 38 is off and the process proceeds to step 116. In step 116, the number of times of processing is incremented by one and the process proceeds to step 118. By rotating the pulse motor 26 by a predetermined amount, the light and dark pattern 16 is moved by the distance of the pitch p, and the process is executed again from step 104. Therefore, this processing is continued until the movement of the light / dark pattern 16 is completed by turning on the other limit switch 38. On the other hand, when the moving amount of the light and dark pattern 16 is about to exceed the movable range, the limit switch 38 is turned on, and the process proceeds to step 121. In step 121, the correction value ΔGT corresponding to the position Hp _i of the light-dark pattern when the change amount of the light intensity stored in step 113 becomes the maximum.
_i is read from the correction value ROM 55, and the routine proceeds to step 122. In the case where the amount of change in light intensity position of the light-dark pattern 16 becomes maximum is different from the position Hp _i light-dark pattern 16 is stored in the correction value ROM55 is by interpolation,
The correction value ΔGT _i is calculated. In step 122, determine the glossiness G by adding the correction value DerutaGT _i read in step 121 to the maximum value Tmax of the amount of change in light intensity, the process proceeds to step 124, the glossiness G obtained in step 122 The value is displayed and this routine ends.

In the main routine for measuring the glossiness of the first embodiment, the maximum value of the change in light intensity is held by moving the light-dark pattern 16 by a predetermined moving pitch p, and the held maximum value Tmax since corrected by advance correction value correction value has been stored in the ROM55 ΔGT _i the exact gloss without being influenced by the curvature of the surface to be measured is determined.

Next, a second embodiment of the present invention will be described. The configuration of the second embodiment of the present invention is the same as the configuration of the first embodiment.

In the gloss measuring apparatus 10 of the second embodiment, the gloss is measured by reducing the influence of the refractive index of the paint on the surface to be measured and the curvature of the surface to be measured.

Here, the reason why the refractive index of the paint on the surface to be measured must be considered when measuring the glossiness will be described below.

Various types of paints are used on the painted surface, and the glossiness of the painted surface painted with these different types of paints must be measured in the same manner. On the other hand, it has been conventionally known that the refractive index of a paint differs depending on the type of the paint. For this reason, the respective light intensity values reflected by the surfaces coated with the paints having different refractive indexes are different. Therefore, even if the glossiness is the same, the value indicating the glossiness measured by the measuring device may be different when the coating is applied with paints having different refractive indexes even if the glossiness is the same. That is, in the glossiness measuring device 10 of the first embodiment,
Since the glossiness is calculated only from the maximum value of the change in light intensity of the light-dark pattern image, the value of the glossiness to be obtained has a relationship proportional to the refractive index of the paint, and is the same as that shown in FIG. The relationship between the refractive indices of the two types of painted surfaces showing the glossiness of the sense is that the refractive index of the paint B is larger than the refractive index of the paint A, and the difference between the light amounts of the bright part and the dark part is IA <
Since IB is satisfied, the value of the gloss is such that paint A <paint B. As described above, even when the visual sensation is the same, there is a problem that the value of the glossiness changes when measuring the measurement target surface on which different paints are applied. Therefore, in order to determine the gloss, it is necessary to consider the refractive index of the paint.

FIG. 2 shows the main routine of the gloss measurement according to the second embodiment. In the second embodiment, the same processing as that of the first embodiment is performed, but the following processing is newly added in consideration of the refractive index of the surface to be measured.

That is, when the initialization in step 100 is completed, the process proceeds to step 102,
In 02, according to a correction value calculation subroutine described later,
A correction value k is obtained. After the correction value k is obtained, the light / dark pattern 16 is moved by a predetermined moving pitch p in the same manner as in the first embodiment, and the maximum value Tma of the light intensity variation is calculated.
x is determined (steps 104 to 11).
4).

In step 114, the light and dark pattern 1
When the amount of movement of 6 is about to exceed the movable range, the limit switch 38 is turned on, and the routine proceeds to step 120. In step 120, the glossiness Q affected by the refractive index of the surface to be measured is calculated based on the maximum value Tmax of the light intensity variation and the correction value k obtained in step 102, and the process proceeds to step 121. In step 121, the correction value ΔGT _i corresponding to the position Hp _i of the light-dark pattern when the change amount of the light intensity stored in step 113 becomes the maximum is stored in the correction value ROM 55.
And proceeds to step 122. Note that the position of the light-dark pattern 16 at which the amount of change in light intensity is the maximum value is the position Hp of the light-dark pattern 16 stored in the correction value ROM 55.
If it is different from _i , the correction value ΔGT _i is calculated by the same interpolation as in the first embodiment. In step 122,
By adding the correction value ΔGT _i read in step 121 to the gloss Q calculated in step 120, the gloss G is obtained.
The value of the gloss G obtained in step 2 is displayed, and this routine ends.

As described above, in the main routine of the gloss measurement according to the second embodiment, first, the light / dark pattern 16 is moved at a predetermined moving pitch p, and the maximum value of the variation of the light intensity is held. Then, since the maximum value of the amount of change in the held light intensity is corrected by the correction value k described later, the glossiness corresponding to the visibility is obtained. The obtained glossiness is stored in a correction value ΔG stored in the correction value ROM 55 in advance.
Since corrected by T _i correct glossiness without being influenced by the curvature is obtained.

As described above, in the second embodiment of the present invention, accurate gloss can be obtained even if the object to be measured is a sample different from the sample of the data stored in the correction value ROM 55.

Next, the subroutine 102 for calculating the correction value will be described with reference to FIG. The subroutine of this correction value calculation is to calculate the correction value k from the reference glass 40 used for calibration of the glossiness measuring device 10 and the surface to be measured.

First, at step 130, the reference glass 40
Is set, and the routine proceeds to step 132, where step 132
Then, the light amount difference value Is is calculated according to a light amount value calculation subroutine described later. In step 134, the surface to be measured for measuring the glossiness is set, and the process proceeds to step 136. In step 136, the light amount difference value Io of the surface to be measured is calculated in the same manner as in step 132. In step 138, the correction value k is calculated based on the obtained light amount difference values Is and Io.
Is calculated by the following equation (5), and this subroutine ends.

[0045]

1 / k = Io / Is Here, it is known that the glossiness is proportional to the refractive index, and in the conventional glossiness measurement device, even if the luminosity shows the same glossiness, When the refractive index of the paint applied to the surface to be measured is large, the glossiness is large, and when it is small, the glossiness is small. Further, the light quantity difference value increases in proportion to the magnitude of the refractive index. For this reason, in the present embodiment, as described above, the glossiness increases when the refractive index of the surface to be measured is smaller than the reference value, and decreases when the refractive index is higher than the reference value. The glossiness is determined using a correction value k that is inversely proportional to the light amount difference value.
When the refractive index is a reference value, the light quantity difference value Is becomes the reference light quantity difference value Io, so that the correction value k becomes 1, and the glossiness is not corrected.

Therefore, the correction value k obtained in this routine
Multiplied by the maximum value of the change in light intensity, the effect of the refractive index of the paint on the surface to be measured is corrected, and the glossiness is determined without being affected by the refractive index of the paint applied to the surface to be measured. Can be As a result, even if the measured object is different from the sample of the data stored in the correction value ROM 55, the data of the correction value ROM 55 can be used.

Note that, as shown in FIG.
Reference numeral 0 denotes a reference glass 41 on one surface and a painted surface 42 coated with, for example, black paint on the other surface, which is used to calibrate the glossiness of the reference glass surface 41. However, the light passing through the reference glass surface 41 is reflected on the back surface of the other painted surface 42 and is returned to the reference glass surface 41 again.
The back surface is inclined at an angle so that a change in the amount of reflected light does not affect the gloss value.

Next, a subroutine 13 for calculating the light amount difference value
2 will be described with reference to FIG.

In this light amount difference value calculation subroutine, the maximum and minimum light amounts are irradiated on the surface to be measured by moving the light-dark pattern 16, and the reflected light from the surface to be measured is measured, as shown in FIG. The light amount difference value I is obtained.

First, in step 140, the light / dark pattern 16 is moved to a position where the light flux passing through the light / dark pattern 16 is minimized, that is, until one of the limit switches 38 of the sliding table is turned on, and step 142 is executed.
In step 142, the output value So of the photoelectric conversion element 24 is fetched, and the flow proceeds to step 144. Step 1
At 44, the light / dark pattern 16 is moved to a position where the luminous flux passing through the light / dark pattern 16 is maximized, that is, until the other limit switch 38 of the sliding table is turned on, and the process proceeds to step 146. At step 146,
The output value Sc of the photoelectric conversion element 24 is fetched, and step 1 is executed.
Go to 48. In step 148, the output value Sc is subtracted from the taken output value So of the photoelectric conversion element 24 to calculate the light amount difference value I, and the present subroutine ends.

As described above, according to the glossiness measuring apparatus according to the second embodiment of the present invention, even if the surface to be measured is coated with different types of paint, the visual sensation is the same. ,
With a gloss without glossiness depending on the type of influence of the paint changes can be quantitatively evaluated, the effect is obtained that an accurate optical <br/> Sawado without influence of curvature can be quantitatively evaluated.

In the first and second embodiments described above, the correction value ΔGT _i stored in the correction value ROM 55 is used.
The glossiness of various curved surfaces is measured in advance, and a value obtained by subtracting the glossiness value of each curved surface from the glossiness value when the measured surface is a reference surface, for example, a flat surface, and a light-dark pattern 1
Although 6 is positioned Hp _i to correspond to the not limited to this, for example, it may be as follows.

[0053] First, the correction value ROM55, instead of the position Hp _i light-dark pattern 16 is stored a variety of curvatures,
Correction value DerutaGT _i may also be stored so as to correspond to the curvature. In this case, the curvature of the surface to be measured is obtained for each measurement, and the correction value Δ stored in the correction value ROM 55 based on the curvature.
What is necessary is just to perform the process of reading and calculating GT _i .

[0054] Second, the correction value ROM55 the value of the ratio of glossiness of gloss and various curved planes, be stored in correspondence with the position Hp _i curvature or light-dark pattern 16 of the curved surface Good. In this case, it may be read the value of the stored ratios in the correction value ROM55 from the position Hp _i of the curved surface of curvature or light-dark pattern 16. Note that the correction value R
When reading the value of the ratio stored in the OM 55, it is necessary to measure the curvature of the surface to be measured for each measurement.

[0055] Thirdly, the correction value ROM55 may be stored glossiness of the plane, and be stored in correspondence glossiness of various curved position Hp _i curvature or light-dark pattern 16 of the curved surface Good. In this case, the correction value from the position Hp _i curvature or light-dark pattern 16 of the measurement surface ROM5
5 is read, the read value is subtracted from the flat gloss value, and the subtracted value is added to the measured gloss value. When reading the value of the ratio stored in the correction value ROM 55 from the curvature, it is necessary to measure the curvature of the surface to be measured for each measurement.

Further, in the above embodiment, the correction value ΔG
Is provided with the correction value ROM55 for storing T _i, not limited to this, for example, stores the calculation equation the measured glossiness can be calculated to correct gloss in accordance with the curvature, Processing may be performed based on this arithmetic expression.

In the above embodiment, the light and dark patterns 16
Is obtained from the number of pulses of the pulse motor 26, but it is sufficient that the position of the light and dark pattern 16 can be grasped. For example, the position of the light and dark pattern 16 may be directly measured by a position detection sensor.

Further, in the above embodiment, the maximum value of the amount of change in the light intensity of the reflected light relative to the unit change amount of the position of the light and dark pattern 16, which is the maximum value of the change amount of the light intensity, is defined as the glossiness. The maximum value of the tangential gradient of the light intensity curve of the reflected light, which is a differential value of the light intensity, may be obtained, and this may be used as the glossiness.

In the above-described embodiment, an example has been described in which the program is used to determine the maximum fluctuation amount of the light intensity by software. However, the present invention is not limited to software but can be performed by electrical hardware. For example, the maximum fluctuation amount may be obtained by a peak hold circuit,
Also, the glossiness can be obtained by combining the differentiation circuit and the peak hold circuit.

In the above embodiment, an example in which a change in sharpness is detected by moving a light-dark pattern has been described. However, the present invention is not limited to moving a light-dark pattern, and the light-dark pattern is fixed. Use, providing a detection aperture such as a pinhole on the incident side of the photoelectric conversion element,
The detection aperture is arranged so that it can move in the direction in which the transmittance of the light and dark pattern image changes, and the detection aperture such as a pinhole is moved so as to change the position of the light and dark pattern image incident on the photoelectric conversion element. The light amount changing from the dark part to the bright part of the image may be detected.

In the above embodiment, an example using a light-dark pattern having a pair of light-dark portions has been described. However, the present invention is not limited to a pattern of a pair of light-dark portions, but a grid having a plurality of light-dark portions. The present invention can easily be applied to a case where glossiness is obtained by detecting contrast using a rectangular pattern having a shape. Also, an example using a transmissive light / dark pattern has been described, but a reflective light / dark pattern may be used.

In the above-described embodiment, the case where the glossiness is corrected using the reference glass has been described. However, the reference calibration and correction data may be stored in advance without using the reference glass. it can.

[0063]

According to the gloss measuring apparatus of the present invention, there is obtained an effect that accurate gloss can be quantitatively evaluated without being affected by curvature.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a gloss measurement control routine according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a gloss measurement control routine according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a correction value calculation subroutine according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a light amount difference value calculation subroutine according to the embodiment of the present invention.

FIG. 5 is a glossiness measuring apparatus to which the present invention is applied.

FIG. 6 is a block diagram of a control circuit according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating a relationship between image forming positions of a light and dark pattern when a surface to be measured is a flat surface and a convex surface.

FIG. 8 is a diagram illustrating a relationship between image forming positions of a light and dark pattern when a surface to be measured is a flat surface and a concave surface.

FIG. 9 is a diagram illustrating a relationship between curvature and glossiness.

FIG. 10 is a perspective view illustrating a shape of a light and dark pattern used in the example of the present invention.

FIG. 11 is a diagram showing the relationship between the position of a pattern, light intensity, and the amount of change in light intensity.

FIG. 12 is a cross-sectional view when a glossiness measuring device to which the present invention is applied is in contact with a surface to be measured, and a diagram showing an arrangement of contacts.

FIG. 13 is a diagram illustrating positions of light and dark patterns when the surface to be measured is a flat surface and a convex surface.

FIG. 14 shows the relationship between the curvature and the gloss, the position Hp _{i of the} pattern where the change rate of the light intensity is maximum, and the correction value ΔGT _i.
It is a diagram showing the relationship with.

FIG. 15 shows a position of a pattern at which the amount of change in light intensity is maximum.
Hp_iCorrection value ΔGT corresponding to _iTo the correction value ROM 55
FIG. 6 is a diagram showing a state stored in the storage device.

FIG. 16 is a diagram illustrating a relationship between a light-dark pattern movement amount and light intensity in different types of paints.

FIG. 17 is a perspective view showing the shape of a reference glass for calibrating a glossiness measuring device used in an example of the present invention.

FIG. 18 is a diagram illustrating a relationship between a light-dark pattern movement amount and light intensity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Glossiness measuring device 16 Light / dark pattern 18 Projection lens 24 Photoelectric conversion element 26 Pulse motor 32 Control circuit

Continuation of the front page (72) Inventor Koji Beta 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (56) References JP-A-63-243738 (JP, A) JP-A-63-119351 (JP) JP-A-63-100310 (JP, A) JP-A-63-243841 (JP, A) JP-A-1-145551 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) G01N 21/00-21/61

Claims (1)

(57) [Claims] 1. A light source, a pattern provided with at least one pair of portions having different light transmittances, and a projection means for projecting light irradiated by the light source and passing through the pattern onto a surface to be measured and forming an image of the pattern. And photoelectric conversion means arranged at a position where the image of the pattern is formed by the projection means and converting the light intensity of the reflected light from the surface to be measured into an electric signal; and incident on the pattern. Pattern moving means for moving the pattern in a direction perpendicular to the optical axis of the light to be transmitted and in which the light transmittance of the pattern changes; and a surface to be measured based on an electric signal input from the photoelectric conversion means. Calculates the maximum value of the amount of change in light intensity or the differential value reflected by, and stores the maximum value in advance according to the curvature of the surface to be measured.
And a calculating means for correcting with the correction value set in advance .