JP2009156789A - Optical characteristic measuring device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical characteristic measuring device and an optical characteristic measuring method capable of measuring accurately an optical characteristic value only by correcting an error caused by deviation of a reflection angle and by output fluctuation of reflected light generated by an influence of a Fresnel reflection characteristic. <P>SOLUTION: This optical characteristic measuring device 1 is equipped with a light irradiation part 11 for irradiating light to a measuring sample SM, a light receiving part 21 having a plurality of light receiving elements for receiving reflected light acquired by reflecting the light irradiated from the light irradiation part 11 by the measuring sample, and an optical characteristic operation part for deriving an optical characteristic based on an output from the light receiving part 21. The optical characteristic operation part determines a corrected output acquired by correcting the output from the light receiving part 21 based on the Fresnel reflection characteristic, and derives the optical characteristic based on the corrected output. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical characteristic measuring apparatus and an optical characteristic measuring method for measuring optical characteristics, preferably optical surface characteristics, more preferably glossiness of a measurement sample.

  2. Description of the Related Art Conventionally, there are known optical characteristic measuring apparatuses that measure optical characteristics of a measurement sample, for example, optical surface characteristics such as glossiness of a sample surface.

  FIG. 9 is a diagram showing an optical configuration of an optical characteristic measuring apparatus in the background art. FIG. 10 is a diagram for explaining a correction method of the optical characteristic measuring apparatus in the background art, and FIG. 10 (A) is a diagram showing an image formed on the light receiving unit in a normal posture, and FIG. FIG. 10 is a diagram showing an image formed on the light receiving unit in a tilted state instead of a normal posture, and FIG. 10C is a diagram showing a state in which the cut-out area follows the image.

  In FIG. 9, the optical characteristic measuring apparatus 100 in the background art includes an illumination side optical system 110 and a light receiving side optical system 120. The illumination side optical system 110 has an angle θ3 with respect to the normal G of the sample surface SMa whose optical axis 113a passes through a certain point on the sample surface SMa of the measurement sample SM, and the light reception side optical system 120 has its optical axis. 122a forms an angle θ4 with respect to the normal G. Specifically, the angle θ3 is an incident angle and the angle θ4 is a reflection angle. In general, the angle θ3 and the angle θ4 are the same value, and the standard is determined based on ASTM D523 and JISZ8741. For example, each of the optical characteristic measuring apparatuses 100 has a predetermined angle of 60 degrees. Parts are placed. Thus, ideal measurement is possible when the incident light (angle θ3) and reflection angle (angle θ4) of the irradiated light with respect to the sample surface SMa are both predetermined angles. Such an arrangement of the measurement sample SM with respect to the optical characteristic device 100 is referred to as a normal posture.

  The illumination side optical system 110 includes a light source unit 111, an illumination side aperture plate 112, and an illumination lens 113. In the illumination side opening plate 112, an illumination side opening 112a is formed so as to penetrate the illumination side opening plate 112.

  The light receiving side optical system 120 includes a light receiving unit 121 and a light receiving lens 122. The light receiving unit 121 includes a plurality of light receiving elements (pixels). These are imaging devices such as CCD (Charge-Coupled Devices).

  The light emitted from the light source unit 111 is regulated to a predetermined opening angle by the illumination side opening 112a of the illumination side aperture plate 112, and is converted into a parallel light beam 111a substantially parallel to the optical axis 113a by the illumination lens 113, and is incident on the sample surface SMa. Irradiated. Then, the light of the component 121 a in the substantially regular reflection direction in the reflected light reflected by the sample surface SMa is converged by the light receiving lens 122 and received by the light receiving unit 121. Then, based on the output of the light receiving unit 121, for example, an optical characteristic value such as the glossiness of the sample surface SMa is obtained.

  However, when the measurement location of the measurement sample SM is not flat, the sample surface SMa may be inclined with respect to the optical property measuring apparatus 100. That is, there is a possibility that the normal posture is lost. If it does so, angle (theta) 3 will change from a predetermined angle, and angle (theta) 4 will also change similarly. As a result, the position of the image formed on the light receiving unit 121 is different from the position of the image formed on the light receiving unit 121 in the normal posture. For this reason, it becomes impossible to measure a correct optical characteristic value.

  Specifically, as shown in FIG. 10A, in the light receiving unit 121, a frame of the cut area 130 that is a certain range is set, and the light reception output within this range is read. Therefore, the position of the image 121b formed on the light receiving unit 121 by reflected light must be within the cut-out area 130. However, when the sample surface SMa is tilted with respect to the optical property measuring apparatus 100 instead of the normal posture, the angle θ3 changes from a predetermined angle, and the angle θ4 also changes. Accordingly, as illustrated in FIG. 10B, the position of the image 121 b in the light receiving unit 121 may change, and part or all of the image 121 b may be formed outside the cutout area 130. In this case, the light reception output read in the cutout area 130 is lower than the output of the entire image 121b. Therefore, the correct optical characteristic value of the measurement sample SM cannot be obtained only by using the light reception output read in the cut area 130.

Therefore, for example, in the optical characteristic measuring apparatus described in Patent Document 1, the cut area 130 moves following the image 121b. Specifically, as shown in FIG. 10C, the cut-out area 130 is arranged so as to include all the images 121b when tilted from the normal posture. Even when the position of the image 121b changes, the cut area 130 moves following the image 121b. For example, the position of the cut area 130 is determined following the maximum intensity of the light reception output in the light receiving unit 121. By doing so, the image 121b is entirely formed within the cut-out area 130, and an optical characteristic value can be obtained based on the output of the entire image 121b.
JP 2006-208361 A

  However, the optical characteristic measuring device described in Patent Document 1 has the following two problems. Specifically, this is a problem caused by Fresnel reflection characteristics. Here, the Fresnel reflection characteristic refers to a characteristic in which, when light is applied to a substance and reflected, the reflectance changes according to the reflection angle.

  First, the first problem will be described. Theoretically, the incident angle and the reflection angle are equal when light is irradiated to a certain substance and reflected. When the material that reflects light, that is, the measurement sample SM has a relatively high gloss, the reflected light is concentrated and distributed at the reflection angle θ4, so that it is not easily affected by the Fresnel reflection characteristics, and the peak of the intensity distribution is substantially equal to θ4. Become. However, when the measurement sample SM has a relatively low gloss, the distribution of the reflected light is dispersed around θ4. As a result, the peak of the intensity distribution is shifted from θ4 due to the influence of the Fresnel reflection characteristics. For example, when the measurement sample SM is a coated plate having a gloss value of 5.7 GU or glass having a gloss value of 8.6 GU, the intensity distribution peak is 62 to 65 degrees even when light is irradiated at an angle θ3 of 60 degrees. Nearby.

  This is because the surface of the low-gloss material is rough, so that the regular reflection component of light is likely to be scattered in various directions, and when the reflection angle is around 60 degrees in a glass with a refractive index of 1.5, This is because the reflectance increases as the reflection angle increases. Therefore, the position of the maximum intensity of the received light output in the light receiving unit 121 is the same as in the case where the sample surface SMa is tilted with respect to the optical property measuring apparatus 100 even though the optical property measurement is performed in the normal posture. Move. In this case, in the optical characteristic measuring apparatus described in Patent Document 1, the cut area 130 moves following the position of the maximum intensity of the light reception output. However, since the posture is actually a normal posture, there is no need to move the position of the cut-out area 130, and since the movement is made, there is a problem that the measurement is not based on the above-mentioned standard and accurate measurement cannot be performed.

  Next, the second problem will be described. As described above, when the reflection angle is around 60 degrees, the reflectance increases as the reflection angle increases due to the Fresnel reflection characteristics. Then, for example, when the measurement surface of the measurement sample SM is not flat, the sample surface SMa is tilted with respect to the optical property measurement apparatus 100, and the reflectance changes, so that the light receiving unit The light reception output at 121 also varies. Therefore, when the normal posture is lost, there is a problem that even if the cutout area 130 follows the image 121b, the output fluctuates, so that accurate output measurement cannot be performed.

  The present invention has been made in view of the above circumstances, and its purpose is to correct an error caused by the influence of Fresnel reflection characteristics, thereby accurately measuring an optical characteristic value and an optical characteristic. It is to provide a measurement method.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, an optical property measurement apparatus according to an aspect of the present invention includes a light irradiation unit that irradiates light to a measurement sample, and a plurality of light beams that receive reflected light that is reflected from the measurement sample. An optical characteristic measuring device comprising: a light receiving unit having a light receiving element; and an optical characteristic calculating unit that derives an optical characteristic based on an output of the light receiving unit, wherein the optical characteristic calculating unit outputs an output of the light receiving unit. A corrected output corrected based on the Fresnel reflection characteristic is obtained, and the optical characteristic is derived based on the corrected output.

  Thereby, the optical characteristic value can be accurately measured by correcting the error caused by the influence of the Fresnel reflection characteristic. Note that the error caused by the influence of the Fresnel reflection characteristic specifically includes a shift in reflection angle and a change in output of reflected light.

  Further, in the above-described optical characteristic measurement apparatus, the optical characteristic calculation unit, when obtaining the correction output, Fresnel reflection by an angle formed by the reflected light received by each light receiving element and the normal line of the measurement sample surface It is preferable to multiply the output of each light receiving element by the reciprocal of the rate.

  Thereby, the correction based on the Fresnel reflection characteristic can be easily realized, and the optical characteristic value can be accurately measured.

  Further, in the above-described optical characteristic measuring apparatus, the optical characteristic calculation unit receives the Fresnel reflectance when the angle formed between the normal line of the measurement sample surface and the reflected light is a normal angle, and each of the light receiving elements receives light. Preferably, the correction output is obtained by multiplying the value obtained by dividing the reflected light by the Fresnel reflectivity by the angle formed by the normal line of the measurement sample surface and the output of each light receiving element.

  Thereby, the correction based on the Fresnel reflection characteristic can be easily realized, and the optical characteristic value can be accurately measured.

  In the above-described optical characteristic measuring apparatus, the optical characteristic calculation unit obtains the correction output using a result obtained by approximating the distribution of the output of the light receiving unit by a distribution function including a component representing the Fresnel reflection characteristic. Is preferred.

  Thereby, the correction based on the Fresnel reflection characteristic can be easily realized, and the optical characteristic value can be accurately measured.

  In the above-described optical property measuring apparatus, it is preferable that the distribution function includes an amount of angular deviation between the measurement sample surface and the measurement reference surface as a parameter.

  As a result, the amount of angular deviation can be obtained accurately, and the optical characteristic value can be measured more accurately.

  Further, in the above-described optical characteristic measuring apparatus, the optical characteristic calculation unit minimizes a difference between an output of each light receiving element and an integrated value obtained by integrating the distribution function in an integration interval corresponding to each light receiving element. As described above, the distribution function is determined, the amount of angular deviation in the determined distribution function is set to 0, a correction distribution function indicating the correction output is obtained, and the correction distribution function is integrated in a predetermined integration interval. It is preferable to derive the optical characteristics.

  Thereby, the fluctuation | variation of the output of reflected light can be correct | amended and an optical characteristic value can be measured more correctly.

  In the above-described optical property measurement apparatus, the Fresnel reflection property is preferably calculated using a refractive index corresponding to the measurement sample.

  Thereby, a more accurate Fresnel reflection characteristic can be obtained and an accurate optical characteristic measurement is possible.

  Moreover, in the above-described optical property measurement apparatus, it is preferable that the optical property calculation unit estimates the refractive index based on an output of the light receiving unit.

  Thus, even when the refractive index of the measurement sample is unknown, correction using the Fresnel reflection characteristic can be performed, and accurate optical characteristic measurement is possible.

  In the above-described optical characteristic measuring apparatus, it is preferable that a refractive index input unit is further provided, and the refractive index is a refractive index input by the refractive index input unit.

  Accordingly, since the accurate refractive index of the measurement sample can be known, correction using the Fresnel reflection characteristic can be performed more accurately, and accurate optical characteristic measurement can be performed.

  Further, in the above-described optical property measurement apparatus, the distribution function includes a refractive index of the measurement sample as a parameter, and the optical property calculation unit approximates the output distribution of the light receiving unit by the distribution function. It is preferable to optimize the refractive index of the measurement sample.

  As a result, the refractive index can be obtained when approximation by the distribution function, and correction can be easily performed.

  Moreover, in the above-described optical characteristic measuring apparatus, it is preferable that the optical characteristic calculation unit derives the optical characteristic based on a correction output in a predetermined clipping range among the correction outputs.

  Thereby, an optimal correction value can be obtained.

  Moreover, in the above-described optical characteristic measuring apparatus, it is preferable that the cut-out range is in the vicinity of a portion having the maximum intensity in the output of the light receiving unit.

  Thereby, an optimal correction value can be obtained.

  An optical property measurement method according to another embodiment of the present invention irradiates a measurement sample with light, and derives the optical property based on the output of reflected light reflected by the measurement sample. In the optical characteristic measuring method, a correction output obtained by correcting the output of the reflected light based on the Fresnel reflection characteristic is obtained, and the optical characteristic is derived based on the correction output.

  Thereby, an error caused by the influence of the Fresnel reflection characteristic can be corrected, and the optical characteristic value can be measured accurately. Note that the error caused by the influence of the Fresnel reflection characteristic is specifically the peak position shift of the intensity distribution and the fluctuation of the output of the reflected light.

  According to the optical characteristic measuring apparatus and the optical characteristic measuring method according to the present invention, it is possible to accurately measure the optical characteristic value by correcting the error caused by the influence of the Fresnel reflection characteristic.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

First, the Fresnel reflectance used in the present invention will be described. An equation that gives amplitude reflectivity at the interface when light is reflected at the interface is called the Fresnel coefficient. In the case of oblique incidence, the Fresnel coefficient has different values for the p wave and the s wave. A light component whose vector vibrates in the incident plane is called a p-wave, and a light component whose vector vibrates perpendicular to the incident plane is called an s-wave. The Fresnel coefficients rp and rs for the p-wave and s-wave when light is incident on the material having a refractive index of n _{1 from} the material having a refractive index of n ₂ are expressed by the following equations (1-1) and (1 -2). However, the incident angle is α and the refraction angle is β. Here, the incident angle refers to the angle formed between the normal line of the interface and the incident light, and the refraction angle refers to the angle formed between the normal line of the interface and the refracted light.

  Further, the p-wave reflectivity Rp and the s-wave reflectivity Rs with respect to the light intensity are expressed by the following equations (2-1) and (2-2), respectively.

  In this specification, the p-wave and the s-wave are considered to be half each, and the Fresnel reflectivity R uses the following formula (3).

  FIG. 1 is a diagram illustrating a configuration of an optical system in the optical characteristic measuring apparatus according to the embodiment. FIG. 2 is a diagram illustrating a configuration of the aperture plate in the optical property measuring apparatus according to the embodiment. FIG. 3 is a diagram illustrating a configuration of a light receiving unit in the optical characteristic measuring apparatus according to the embodiment. FIG. 4 is a diagram illustrating an electrical configuration of the optical characteristic measuring apparatus according to the embodiment.

  First, the optical configuration of the optical property measuring apparatus 1 according to an embodiment of the present invention will be described. 1 to 3, the optical characteristic measuring apparatus 1 receives an illumination-side optical system (light irradiating unit) 10 that irradiates a predetermined region on the sample surface SMa of the measurement sample SM and the reflected light from the predetermined region. And a light receiving side optical system 20.

  The illumination side optical system 10 and the light receiving side optical system 20 are arranged in regions opposite to each other with respect to the normal line G of the sample surface SMa passing through a certain point on the sample surface SMa of the measurement sample SM. The illumination side optical system 10 has an angle θ1 with respect to the normal G of the sample surface SMa whose optical axis 13a passes through a certain point on the sample surface SMa of the measurement sample SM, and the light reception side optical system 20 has its optical axis. 22a forms an angle θ2 with respect to the normal G. Specifically, the angle θ1 is an incident angle and the angle θ2 is a reflection angle. In general, the angle θ1 and the angle θ2 are the same value.

  The angle θ1 and the angle θ2 may be arbitrary angles. However, when the measurement sample SM is in a normal posture with respect to the optical property measuring apparatus 1, the angle θ1 and the angle θ2 are standardized by, for example, ISO or JIS. , 20 degrees, 60 degrees, or 85 degrees. In this embodiment, in order to measure 60 degree gloss, which is an example of optical characteristics, the angle θ1 and the angle θ2 in the normal posture are set to 60 degrees, which is a predetermined angle based on the definition of ASTM D523. Therefore, the illumination-side optical system 10 and the light-receiving side optical system 20 are respectively arranged so that the optical axis 13a and the optical axis 22a are line-symmetric with respect to the normal line G of the sample surface SMa. Yes. Note that the angle θ1 and the angle θ2 in the normal posture are referred to as normal angles. In the present embodiment, the normal angle is 60 degrees.

  The illumination-side optical system 10 includes a light source unit 11, an illumination-side aperture plate 12, and an illumination lens 13. The light source unit 11, the illumination-side aperture plate 12 and the illumination lens 13 have their optical axes in order from the sample surface SMa. It arrange | positions along with the optical axis 13a.

  The light source unit 11 is configured to include a light emitting element such as an LED, and is a device that emits light toward the sample surface SMa. The illumination side aperture plate 12 is a member that regulates the light emitted from the light source unit 11 toward the sample surface SMa to a predetermined opening angle. In this embodiment, for example, the illumination-side aperture plate 12 is a plate-like member formed of a material that blocks the wavelength of light emitted from the light source unit 11 and irradiating the sample surface SMa, as shown in FIG. The illumination side opening 12 a is drilled so as to penetrate the illumination side opening plate 12. This illumination side opening 12a has an angle of view, a width (substantially up and down direction in FIG. 1 in the drawing) w is 0.75 degree, and a height (vertical direction in FIG. 1) h is 2.5 degree. It is a rectangular shape. The illumination lens 13 is an optical element that guides the light that has passed through the illumination side aperture 12a of the illumination side aperture plate 12 to the sample surface SMa as a parallel light beam 11a substantially parallel to the optical axis 13a.

  The light receiving side optical system 20 includes a light receiving unit 21 and a light receiving lens 22, and the light receiving unit 21 and the light receiving lens 22 are arranged in order of distance from the sample surface SMa with their optical axes aligned with the optical axis 22a. The light receiving lens 22 is an optical element that collects reflected light from the sample surface SMa of the measurement sample SM and guides it to the light receiving surface of the light receiving unit 21.

  The light receiving unit 21 includes a plurality of light receiving elements including photoelectric conversion elements that convert light energy into electric energy, and in the present embodiment, each output is directly extracted from each light receiving element. The light receiving unit 21 has a light receiving surface larger than a target region for which optical characteristics are to be obtained. Each light receiving element of the light receiving unit 21 receives the light in the reflected light that is irradiated onto the sample surface SMa by the illumination side optical system 10 and reflected by the sample surface SMa, thereby outputting an electrical signal corresponding to the amount of light received. .

  In the illumination-side optical system 10 and the light-receiving side optical system 20, light is received so that the position of the illumination-side opening 12a in the illumination-side aperture plate 12 and the position of the light-receiving surface in the light-receiving unit 21 are optically conjugate. A portion 21 is provided. If the change in the posture of the measurement sample SM is up to a predetermined angle set in advance, the size of the light receiving surface and the light receiving lens 22 are adjusted so that the component in the substantially regular reflected light direction is incident on the light receiving surface of the light receiving unit 21. The focal length f is set.

  In the present embodiment, for example, as shown in FIG. 3, the light receiving unit 21 includes seven light receiving elements p0 to p6 arranged in one direction, and outputs are directly extracted from the light receiving elements p0 to p6. A silicon photodiode array configured as described above is provided. Here, when light is irradiated and an image of the illumination side opening 12a of the illumination side opening plate 12 is formed on the light receiving surface of the light receiving unit 21, the width w direction of the illumination side opening 12a and each of the light receiving elements p0 to p6. The light receiving unit 21 is disposed at the focal position f of the light receiving lens 22 so that the arrangement direction matches. In the case of the normal posture, the angle θ2 is 60 degrees as described above. At this time, the light receiving elements p0 to p6 are arranged so that the peak of the light intensity of the component 21a in the substantially regular reflection direction is irradiated to p2 among the seven light receiving elements p0 to p6. When the angle of the reflected light changes and the angle θ2 becomes 56 degrees, 58 degrees, 62 degrees, 64 degrees, 66 degrees, and 68 degrees, the light receiving elements p0, p1, p3, p4, respectively. , P5, and p6, the light receiving elements p0 to p6 are arranged such that the peak position of the light intensity of the component 21a in the substantially regular reflection direction comes.

  Next, the electrical configuration of the optical property measuring apparatus 1 will be described. In FIG. 4, the optical characteristic measuring apparatus 1 is abbreviated as a light source unit 11, a light receiving unit 21, a control unit 31, a light emission driving unit 32, and an analog / digital conversion unit (hereinafter referred to as “A / D conversion unit”). ) 33, a storage unit 34, a display unit 35, and an input operation unit 36.

  The light source unit 11 and the light receiving unit 21 correspond to the light source unit 11 and the light receiving unit 21 illustrated in FIG. The light emission drive unit 32 is a circuit that causes the light source unit 11 to perform a light emission operation according to the control of the control unit 31. The A / D conversion unit 33 is a circuit that converts the analog output of the light receiving unit 21 into a digital signal composed of a plurality of bits (for example, 8 bits or 10 bits). Each output from each light receiving element in the light receiving unit 21 is input to the A / D conversion unit 33 in parallel or serially. The storage unit 34 is a circuit that temporarily stores the digital signal output from the A / D conversion unit 33, and is used as a work area for performing various processes by the control unit 31 on the digital signal.

  The display unit 35 is a circuit that displays an operation result of the input operation unit 36, an optical characteristic value such as glossiness of the measurement sample SM derived by the control unit 31, a refractive index of the measurement sample SM, and the like. A display circuit such as a liquid crystal display or an organic EL display is provided. The input operation unit 36 includes a power button circuit for switching on / off of the main power supply of the optical characteristic measuring apparatus 1, a switch circuit for inputting a measurement start instruction for instructing measurement start of the optical characteristic, and the like. Further, the input operation unit 36 may function as a refractive index input unit for inputting the refractive index of the measurement sample SM. That is, a button circuit for instructing a predetermined refractive index may be included. By inputting the refractive index of the measurement sample SM from the input operation unit (refractive index input unit) 36, the correct Fresnel reflectance can be calculated and more accurate correction can be performed. In addition to the input operation unit 36, a refractive index input unit may be provided.

The control unit 31 is a circuit that controls each unit according to the function in order to measure the optical characteristics of the measurement sample SM. For example, the control unit 31 includes a microcomputer that includes a storage element that stores, for example, a control program, a microprocessor that operates according to the control program, and its peripheral circuits. Examples of the storage element include a nonvolatile ROM (Read Only Memory), a rewritable nonvolatile EEPROM (Electrically Erasable Programmable Read Only Memory), and a volatile RAM (Random Access Memory).
And so on. The control unit 31 functionally includes a light emission control unit 31a, a light reception control unit 31b, an optical characteristic calculation unit 31c, and a display control unit 31d.

  The light emission control unit 31a controls the operation of the light emission drive unit 32. When an instruction to start optical characteristic measurement of the measurement sample SM is input by the input operation unit 36, the light emission unit 31a performs a light emission operation for a predetermined time. Let it be done. The light reception control unit 31b controls the operation of the A / D conversion unit 33. When an instruction to start measuring the optical characteristics of the measurement sample SM is input by the input operation unit 36, the light reception control unit 31b corresponds to the light emission timing of the light source unit 11. Thus, the A / D converter 33 is caused to convert the analog output of the light receiving unit 21 into a digital signal. The optical characteristic calculation unit 31 c derives the optical characteristic of the measurement sample SM based on the digital signal from the A / D conversion unit 33.

  In the present embodiment, the optical characteristic calculation unit 31c derives the optical characteristic of the measurement sample SM based on the output of the light receiving unit 21 and the Fresnel reflection characteristic. The display control unit 31d causes the display unit 35 to display the optical characteristic value calculated by the optical characteristic calculation unit 31c. In addition, the display control unit 31d may display not only the optical characteristic value but also the amount of angular deviation, the direction in which the sample surface SMa is inclined with respect to the measurement reference plane, and the like on the display unit 35. Here, the amount of angular deviation refers to the amount of deviation between the sample surface SMa and the measurement reference plane that occurs when the sample surface SMa is a curved surface, in other words, the normal angle (60 degrees) and the angle θ1 after the change. And the difference. Therefore, if the posture is normal, the amount of angular deviation is zero.

  The user can judge the reliability of measurement from the display content. The display of the angle and the like is preferably performed by a character or a graph so that the user can easily understand. Furthermore, when the amount of angular deviation exceeds a certain range, it is preferable that a warning message is displayed to notify the user that the correction reliability is low and it is difficult for the user to overlook. In addition, the optical characteristic measuring apparatus 1 is good also as providing a warning buzzer etc. so that a warning sound may be sounded simultaneously with a warning message.

  The control unit 31, the display unit 35, and the input operation unit 36 may be configured by external devices such as a personal computer, a display device, and a keyboard.

  Next, the operation of the optical property measuring apparatus 1 will be described. FIG. 5 is a diagram for explaining an optical characteristic calculation procedure in the embodiment. FIG. 5A is a diagram illustrating output values of the respective light receiving elements in the light receiving unit. FIG. 5B shows the output value of each light receiving element after correction. 5A and 5B, the horizontal axis represents the light receiving element pn (n = 0 to 6), and the vertical axis represents the output value Pn of the light receiving element pn and the corrected output value Rn. . FIG. 5C is a diagram showing an intensity distribution (gloss profile) derived based on the output of the light receiving unit before and after correction, and FIG. 5D is an output clipping position represented by the intensity distribution. FIG. 5 (C) and 5 (D), the horizontal axis is the x-axis, and the vertical axis represents the output. The x-axis is set in the arrangement direction of the light receiving elements p0 to p6 as shown in FIGS.

  When the user places the measurement sample SM in the optical property measurement apparatus 1, receives the refractive index of the measurement sample SM from the input operation unit 36, and inputs an instruction to start optical property measurement, the light emission control unit 31 a of the control unit 31. Causes the light source unit 11 to perform a light emission operation.

  The light emitted from the light source unit 11 is regulated to a predetermined opening angle by the illumination side opening 12a of the illumination side opening plate 12, and is made into a parallel light beam 11a substantially parallel to the optical axis 13a by the illumination lens 13, and the measurement sample SM The sample surface SMa is irradiated. Then, the light of the component 21 a in the substantially regular reflection direction in the reflected light reflected by the sample surface SMa is converged by the light receiving lens 22 and received by the light receiving unit 21.

  The light reception control unit 31 b of the control unit 31 causes the A / D conversion unit 33 to perform an operation of converting the analog output of the light reception unit 21 into a digital signal according to the light emission timing of the light source unit 11. In the present embodiment, the light receiving unit 21 includes seven light receiving elements p0 to p6 as described above, and the analog output of each of the light receiving elements p0 to p6 is converted into a digital signal by the A / D conversion unit 33. Is converted to For example, as shown in FIG. 5A, the light receiving element p0 outputs a light receiving output value P0, the light receiving element p1 outputs a light receiving output value P1, the light receiving element p2 outputs a light receiving output value P2, and the light receiving element At p3, the light receiving output value P3 is output, the light receiving element p4 outputs the light receiving output value P4, the light receiving element p5 outputs the light receiving output value P5, and the light receiving element p6 outputs the light receiving output value P6.

  The optical characteristic calculation unit 31c of the control unit 31 corrects each light reception output value P0 to P6 using the Fresnel reflection characteristic. First, the reciprocal of the Fresnel reflection characteristic used in this correction will be described with reference to FIG. FIG. 6 is a diagram for explaining the reciprocal of the Fresnel reflection characteristic. 6A is a diagram showing the Fresnel reflection characteristics and the reciprocal of the Fresnel reflection characteristics, and FIG. 6B is a diagram showing the count value of the reciprocal of the Fresnel reflection characteristics. In FIG. 6A, the horizontal axis is the x-axis, and the vertical axis represents the reflectance. However, since the reciprocal of the Fresnel reflection characteristic is a normalized unitless value, the reflectance on the vertical axis indicates the Fresnel reflection characteristic. The x-axis is set in the arrangement direction of the light receiving elements p0 to p6 as shown in FIGS. In FIG. 6B, the horizontal axis represents the light receiving element pn (n = 0 to 6), and the vertical axis represents the reciprocal value of the Fresnel reflection characteristic.

  Specifically, the Fresnel reflection characteristic shown in FIG. 6A shows the relationship between the reflectance and x. The reciprocal of the Fresnel reflection characteristic specifically depends on the angle θ2 between the reflected light received by each of the light receiving elements p0 to p6 and the normal line G of the sample surface SMa with respect to each of the light receiving elements p0 to p6. The inverse of the Fresnel reflectivity is multiplied by the Fresnel reflectivity when the angle θ2 is a normal angle (60 degrees). The reason why the Fresnel reflectance is multiplied when the angle θ2 is a normal angle (60 degrees) is that this value is not changed before and after the correction with reference to the output value at the light receiving element p2 at the normal angle.

  In other words, in other words, the inverse of the Fresnel reflection characteristics, the Fresnel reflectivity when the angle θ2 is a normal angle (60 degrees) is the reflected light received by each of the light receiving elements p0 to p6 and the normal line G of the sample surface SMa. It is a value divided by the Fresnel reflectivity according to the formed angle θ2. Therefore, when the x coordinate is the position of the light receiving element p2 corresponding to the normal angle, the reciprocal of the Fresnel reflection characteristic is 1. The Fresnel reflection characteristic is represented by a broken line, and the reciprocal of the Fresnel reflection characteristic is represented by a solid line.

  In the Fresnel reflection characteristic, the reflectance increases as the value of x increases. However, the inverse of the Fresnel reflection characteristic decreases as the value of x increases. FIG. 6B shows the reciprocal of the Fresnel reflection characteristic shown in FIG. 6A as a count value for each of the corresponding light receiving elements p0 to p6. Specifically, Q0 is a value obtained by dividing the Fresnel reflectance when the angle θ2 is 60 degrees by the Fresnel reflectance when the angle θ2 is 56 degrees, and Q1 is the Fresnel reflectance when the angle θ2 is 60 degrees. Is divided by the Fresnel reflectivity when the angle θ2 is 58 degrees, and Q2 is the value obtained by dividing the Fresnel reflectivity when the angle θ2 is 60 degrees by the Fresnel reflectivity when the angle θ2 is 60 degrees. Q3 is a value obtained by dividing the Fresnel reflectivity when the angle θ2 is 60 degrees by the Fresnel reflectivity when the angle θ2 is 62 degrees, and Q4 is the Fresnel reflectivity when the angle θ2 is 60 degrees. Q5 is a value divided by the Fresnel reflectivity when the angle θ2 is 60 degrees, and Q5 is a value obtained by dividing the Fresnel reflectivity when the angle θ2 is 60 degrees and Q6 is the angle divided by the Fresnel reflectivity when the angle θ2 is 66 degrees. The Fresnel reflectivity when θ2 is 60 degrees is expressed as the angle θ 2 is a value divided by Fresnel reflectivity when 68 degrees.

  The optical characteristic calculation unit 31c stores in advance the count values Q0 to Q6 of the reciprocal number of the Fresnel reflection characteristic shown in FIG. 6B, for example, according to the refractive index of the measurement sample SM, or an interpolation calculation. Ask for it. The refractive index of the measurement sample SM may be a value input by the user from the refractive index input unit. Then, the count values Q0 to Q6, which are the reciprocal of the Fresnel reflection characteristics, are multiplied by the respective received light output values P1 to P6 corresponding to the respective light receiving elements p0 to p6. As a result, the received light output values P1 to P6 are corrected, and the corrected received light output values R1 to R6 are derived. The corrected light reception output values R1 to R6 are specifically shown in FIG.

  As can be seen by comparing FIG. 5A and FIG. 5B, the light reception output value P4 of the light receiving element p4 was the maximum output value before correction, but after correction, the light reception output corrected by the light receiving element p3 was corrected. The output value R3 is the maximum output value. After correction, since the position of the light receiving element p3 is at the maximum output, the reflection angle is 62 degrees. Since the difference between the corrected peak position and the normal angle (60 degrees) is 2 degrees, the amount of angular deviation between the sample surface SMa and the measurement reference plane is 2 degrees. The light reception output value P2 of the light receiving element p2 corresponding to the normal angle (60 degrees) is equal to the corrected light reception output value R2.

  Further, the optical characteristic calculation unit 31c of the control unit 31 is based on the corrected light reception output values R1 to R6, and is a straight line extending in one direction set on the light receiving surface of the light receiving unit 21, for example, FIG. 1 and FIG. An intensity distribution (gloss profile) representing the distribution of the amount of reflected light received along the x-axis is obtained. Specifically, the gloss profile is shown in FIG. FIG. 5C also shows a gloss profile obtained based on the light reception output values P1 to P6 before correction for comparison. Specifically, the gloss profile before correction is represented by a broken line, and the gloss profile after correction is represented by a solid line. As described above, as shown in FIG. 5C, it can be seen that the position of the maximum output is different between after correction and before correction. Further, the maximum output value is also different, and the maximum output value is reduced after the correction. Thus, both the amount of angular deviation and the output value are corrected by the above correction.

  Next, as shown in FIG. 5D, the optical property calculator 31c determines a cut area (cut range) that is an area used for gloss calculation from the obtained gloss profile. Specifically, the cut-out area is a range W allocated by W / 2 to the plus side and the minus side along the x axis with the peak position of the gloss profile as the center. In the present embodiment, the cut-out area range W is 4.4 degrees. As described above, in the present embodiment, the predetermined angles θ1 and θ2 that are normal angles are set to 60 degrees in accordance with the standard for the gloss value measurement. In this case, W is 4.4 degrees. It is because it has become. The determination of the cut-out area is not limited to this method. For example, the cut-out area may be set to a range W that is assigned W / 2 on the plus side and the minus side along the x-axis with the center of gravity of the gloss profile as the center. Further, the gloss profile may be integrated with respect to the range W in a certain range, and the integrated value may be the largest.

  When the cut area is determined, the received light intensity Ru within the range of the determined cut area in the gloss profile is obtained. In order to obtain the received light intensity Ru, for example, the sum total of the count values of the gloss profile within the cut-out area may be obtained. In addition, in the count value of the part concerning the edge part of a cutting area, a count value may be apportioned according to the range of a cutting area, and another interpolation method may be used. When the received light intensity Ru is obtained, the gloss value is obtained using it. For example, when the received light intensity when measuring the calibrated calibration plate is Cs and the gloss value valued on the calibration plate is Gc, the gloss value Gu is expressed by the following equation (4).

  As described above, according to the optical characteristic measuring apparatus of the present embodiment, correction is performed so as to remove the influence of the Fresnel reflection characteristic, so that more accurate optical characteristic measurement can be performed.

  The Fresnel reflection characteristic is a principle applicable to specular reflection light, and does not correspond to diffuse light. Therefore, when deriving optical characteristic values such as the gloss value, the specular reflection component with the diffusion component removed is used. It is desirable to use only gloss profiles. In order to separate the diffusion component, a known method may be used. For example, a known method for obtaining the contrast glossiness, that is, an optical system similar to a regular reflection light receiving optical system is also arranged in a diffusion direction such as a direction perpendicular to the sample surface SMa so that regular reflection light and diffuse reflection are obtained. A method for obtaining the light ratio may be used.

  Further, even when the user does not input the refractive index of the measurement sample SM, the optical characteristic measurement apparatus 1 estimates the refractive index of the measurement sample SM based on the gloss value derived without correction. Correction may be performed using the Fresnel reflectance calculated using the refractive index.

  FIG. 7 is a diagram showing Fresnel reflection characteristics of silver and glass. The horizontal axis is the reflection angle, and the vertical axis is the reflectance. Silver is a metal and the refractive index is ∞ (infinite). The glass shown in FIG. 7 has a refractive index of 1.567. As can be seen from FIG. 7, the Fresnel reflection characteristics differ greatly between glass and silver. As shown in FIG. 7, the reflectance of silver does not depend much on the reflection angle, and is a substantially constant value. However, the reflectance of glass is substantially constant until the reflection angle is about 60 degrees, but the reflectance increases rapidly as the reflection angle increases beyond that. Glass and silver also differ in gloss value. Specifically, the refractive index of a substance having a gloss value of 100 GU or more tends to be close to the refractive index of a metal, and the refractive index of a substance having a gloss value of less than 100 GU tends to be close to the refractive index of glass. By utilizing this fact, the measurement sample SM is classified into a substance having a refractive index close to that of a metal or a substance close to glass, and the refractive index of the measurement sample SM can be estimated based on the classification. For example, with 100 GU as a boundary, if 100 GU or more, the metal may be used, and if less than 100 GU, the glass may be estimated.

  Specifically, first, in the optical characteristic measuring apparatus 1, the gloss value of the measurement sample SM is obtained without correction. If the gloss value is 100 GU or more, the optical property calculation unit 31c calculates the Fresnel reflectivity with an infinite refractive index, and if the value is less than 100 GU, the Fresnel reflectivity is calculated with a refractive index of 1.567. And the optical characteristic calculating part 31c can perform sufficient correction, though roughly, by performing the above-described correction using the calculated Fresnel reflectance. In the above description, the two refractive indexes are estimated based on the gloss value of 100 GU. However, other gloss values may be used as a reference, and the refractive index estimated by further increasing the number of references. You can increase the number.

  The light receiving unit 21 of the optical characteristic measuring apparatus 1 according to the embodiment of the present invention has a configuration in which the light receiving elements p0 to p6 are arranged in the x-axis direction, and is a so-called one-dimensional arrangement. However, the optical characteristic measuring apparatus of the present invention is not limited to this arrangement, and for example, the light receiving elements may be arranged in a two-dimensional manner. Also in this case, as in the case of the one-dimensional arrangement, each light receiving element can be obtained so that the angle formed between the normal G of the sample surface SMa and the reflected light when each light receiving element has a light peak can be obtained. May be arranged. Accordingly, the Fresnel reflectance can be calculated based on the output of each light receiving element, and correction can be performed.

  Next, a description will be given of an optical characteristic measuring apparatus 1 that is another aspect of the optical characteristic measuring apparatus according to the present embodiment and that is different from the above-described method in the correction method by the optical characteristic calculating unit 31c. Also in this correction, similarly to the optical characteristic measuring apparatus 1 according to the above-described embodiment, the optical characteristic calculation unit 31c uses the Fresnel reflection characteristic to correct an error caused by the Fresnel reflection characteristic. Specifically, correction is performed using a result obtained by approximating the distribution of the output obtained by the light receiving unit 21 to a distribution function taking into account the Fresnel reflection characteristics. Hereinafter, a calculation method of the optical characteristic calculation unit 31c of the optical characteristic measurement apparatus which is another aspect will be described.

  The calculation procedure of the optical characteristic calculation unit 31c in another aspect of the optical characteristic measurement apparatus according to the present embodiment will be described with reference to FIG. FIG. 8 is a diagram for explaining an optical characteristic calculation procedure in another correction method. FIG. 8A is a diagram showing the output value of each light receiving element in the light receiving unit, the horizontal axis represents the light receiving element pn (n = 0 to 6), and the vertical axis represents the output of the light receiving element pn. The value Pn is indicated. FIG. 8B is a diagram showing a distribution function P (x) approximating the output of the light receiving unit 21, and FIG. 8C is an integration of the distribution function P ′ (x) for obtaining an optical characteristic value. It is a figure for demonstrating a range. The horizontal axis of FIGS. 8B and 8C is the x-axis, and the vertical axis represents the function value P (x) of the distribution function. The x-axis is set in the arrangement direction of the light receiving elements p0 to p6 as shown in FIGS.

  The optical characteristic calculator 31c of the controller 31 first determines the amount of reflected light received along a straight line set in one direction set on the light receiving surface of the light receiver 21, for example, the x-axis shown in FIGS. A distribution function P (x) representing the distribution is obtained based on the output of the light receiving unit 21. More specifically, the optical characteristic calculation unit 31c of the control unit 31 approximates the output of the light receiving unit 21 with a one-dimensional distribution function P (x).

  Specifically, the distribution function P (x) to be used is expressed by Equation (5). P (x) includes a Fresnel reflection characteristic.

Here, x represents an arbitrary position on the x-axis, and a represents a case where one minutely decomposed light at an arbitrary position of the light beam from the light source unit 11 is incident on the sample surface SMa and reflected. The center position of the gloss profile in the light receiving part 21 is shown. f is a focal length of the light receiving lens 22, and n ₁ is a refractive index of a medium that is propagated before the light from the light source unit 11 enters the measurement sample SM, that is, air. n ₂ is the refractive index of the measurement sample SM. For example, if the measurement sample SM is glass, the refractive index is 1.567, and if it is a metal, the refractive index is infinite. p is the width of the image along the x-axis in the light receiving unit 21 when the sample surface SMa is a mirror surface. Further, θi may be a value of the angle θ1 and the angle θ2 in the normal posture. In this embodiment, since 60 degrees is used as described above, θi may be set to 60.

  x0 is the center coordinate of the distribution of the received light amount in the light receiving unit 21, and indicates the amount of angular deviation. N is the width of the regular reflection component of the reflected light, L is the emission intensity of the diffuse component of the reflected light, and S is the emission intensity of the regular reflection component of the reflected light. P (x) is determined when these x0, N, L, and S are determined.

  Therefore, the optical characteristic calculation unit 31c uses the light reception output values P0 to P6 of the light receiving elements p0 to p6 in the light receiving unit 21, and the center coordinates x0 of the distribution of the received light amount of Expression (5), the regular reflection component of the reflected light , The emission intensity L of the diffuse component of the reflected light, and the emission intensity S of the regular reflection component of the reflected light, the distribution function P (x) representing the output of the light receiving unit 21 is obtained, and the output of the light receiving unit 21 is approximated To do. More specifically, as shown in FIGS. 8A and 8B, the light receiving output values P0 to P6 of the light receiving elements p0 to p6 and the ranges corresponding to the light receiving regions of the light receiving elements p0 to p6. Thus, the distribution function P (x) is obtained so that the integrated values T0 to T6 obtained by integrating the distribution function P (x) of the equation (5) are the best, and the output of the light receiving unit 21 is approximated. Note that T0 to T6 are respectively obtained by the following equation (6). Here, xsn (n = 0 to 6) is the center position of each of the light receiving elements p0 to p6, and swa is the width along the x-axis direction of each of the light receiving elements p0 to p6.

  More specifically, the difference between the light receiving output values P0 to P6 of the light receiving elements p0 to p6 and the T0 to T6 expressed by the expression (6) in the range corresponding to the light receiving regions of the light receiving elements p0 to p6. The values of the unknowns x0, N, L, and S are determined so that the sum of squares D is minimized. The square sum D is expressed by the following equation (7). The distribution function P (x) is determined from the determined unknowns x0, N, L, and S, and the output of the light receiving unit 21 is approximated.

  When the measurement sample SM is a low-gloss material, a phenomenon occurs in which the reflection angle increases due to the influence of the Fresnel reflection characteristics. However, the distribution function P (x) is corrected because the Fresnel reflection characteristics are taken into account. Angle deviation amount x0 can be obtained correctly.

  Furthermore, in the determined distribution function P (x), the optical characteristic calculator 31c substitutes 0 for the angle deviation amount x0 to obtain the distribution function P ′ (x) shown in FIG. The distribution function P ′ (x) represents a gloss profile when the optical characteristics are measured in an ideal measurement state with no angular deviation and in a normal posture. In the distribution function P ′ (x), a phenomenon in which the output value increases or decreases due to the influence of Fresnel reflection characteristics is also corrected.

  Next, as shown in FIG. 8C, the optical characteristic calculation unit 31c sets the obtained distribution function P ′ (x) in a range corresponding to a width W = 4.4 degrees centering on x = 0. Integrate with respect to (−W / 2 to W / 2, integration interval) to obtain an integral value S. In other words, the optical characteristic calculation unit 31c obtains the integral value S of the distribution function P ′ (x) using Equation 3. Specifically, the integral value S is represented by the following equation (8).

Further, the gloss value in the range W of the cut area is obtained from the obtained integrated value S.
As described above, the optical property calculation unit 31c in the optical property measurement apparatus 1 according to the second embodiment corrects an error due to the influence of the Fresnel reflection property by approximation using a distribution function, and thereby provides a more accurate optical property value. Can be measured.

As a method for setting the refractive index of the measurement sample SM necessary for obtaining the Fresnel reflection characteristics, the above-described method may be used, and the refractive index n ₂ of the measurement sample SM is also set as an unknown in the equation (5). Alternatively, the refractive index n ₂ may also be determined when obtaining the other unknowns x0, N, L, and S.

  As described above, the optical characteristic measuring apparatus 1 according to the embodiment of the present invention has an effect of correcting an error caused by the influence of the Fresnel reflection characteristic and performing an accurate optical characteristic measurement. In the above description, the case where the gloss value is measured by the optical property measuring apparatus of the present invention has been described. However, not only the gloss value but also other optical properties such as a haze value and a color system value can be measured. . Similarly, an optical property measurement method can also be realized, whereby accurate optical property measurement can be performed.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Accordingly, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. It is interpreted that it is included in

It is a figure which shows the structure of the optical system in the optical characteristic measuring apparatus of embodiment. It is a figure which shows the structure of the aperture plate in the optical characteristic measuring apparatus of embodiment. It is a figure which shows the structure of the light-receiving part in the optical characteristic measuring apparatus of embodiment. It is a figure which shows the electrical structure in the optical characteristic measuring apparatus of embodiment. It is a figure for demonstrating the calculation procedure of the optical characteristic in embodiment, Comprising: FIG. 5 (A) is a figure which shows the output value of each light receiving element in a light-receiving part, FIG.5 (B) is each after correction | amendment. FIG. 5C is a diagram showing the intensity distribution (gloss profile) derived based on the output of the light receiving unit before and after correction, and FIG. 5D shows the output value of the light receiving element. FIG. 4 is a diagram for explaining an output cut-out position represented by an intensity distribution. FIGS. 6A and 6B are diagrams for explaining the reciprocal of the Fresnel reflectivity, FIG. 6A is a diagram illustrating the Fresnel reflection characteristic and the reciprocal of the Fresnel reflection characteristic, and FIG. 6B is a count of the reciprocal of the Fresnel reflection characteristic. It is a figure which shows a value. It is a figure which shows the Fresnel reflection characteristic of silver and glass. FIGS. 8A and 8B are diagrams for explaining a calculation procedure of optical characteristics in the embodiment, in which FIG. 8A is a diagram illustrating output values of light receiving elements in the light receiving unit, and FIG. Is a diagram illustrating a distribution function P (x) that approximates, and FIG. 8C is a diagram for explaining an integration range of the distribution function P ′ (x) for obtaining an optical characteristic value. It is a figure which shows the optical structure of the optical characteristic measuring apparatus in background art. 10A and 10B are diagrams for explaining a correction method of the optical characteristic measuring apparatus in the background art, in which FIG. 10A is a diagram showing an image formed on the light receiving unit in a normal posture, and FIG. 10B is a normal posture. FIG. 10C is a diagram illustrating an image formed on the light receiving unit in a state of being inclined and FIG. 10C is a diagram illustrating a state in which the cut-out area follows the image.

Explanation of symbols

1, 100 optical property measuring device,
10, 110 Illumination side optical system 11, 111 Light source 11a, 111a Parallel light beam 12, 112 Illumination side aperture plate 12a, 112a Illumination side aperture 13, 113 Illumination lens 13a, 113a Optical axis 20, 120 Light reception side optical system 21, 121 Light receiving unit 21a, 121a Components 22a, 122a in substantially regular reflection direction Optical axis 22, 122 Light receiving lens 31 Control unit 31a Light emission control unit 31b Light reception control unit 31c Optical characteristic calculation unit 31d Display control unit 32 Light emission drive unit 33 A / D conversion Unit 34 storage unit 35 display unit 36 input operation unit 121b image 130 clipping area

Claims (13)

A light irradiating unit for irradiating light to the measurement sample, a light receiving unit having a plurality of light receiving elements for receiving reflected light reflected by the measurement sample, and an output of the light receiving unit. An optical property measurement device comprising an optical property calculation unit that derives optical properties based on
The optical characteristic measurement device is characterized in that the optical characteristic calculation unit obtains a correction output obtained by correcting the output of the light receiving unit based on a Fresnel reflection characteristic, and derives the optical characteristic based on the correction output.   The optical characteristic calculator calculates the reciprocal of the Fresnel reflectivity according to the angle formed by the reflected light received by each light receiving element and the normal of the measurement sample surface when obtaining the correction output. The optical characteristic measuring device according to claim 1, wherein the optical property is multiplied by an output.   The optical characteristic calculation unit calculates the Fresnel reflectivity when the angle formed between the normal line of the measurement sample surface and the reflected light is a normal angle, and the reflected light received by each of the light receiving elements and the measurement sample surface. The optical characteristic measurement apparatus according to claim 1, wherein the correction output is obtained by multiplying a value obtained by dividing the Fresnel reflectance by an angle formed with a normal with the output of each light receiving element.   The optical characteristic measurement apparatus according to claim 1, wherein the optical characteristic calculation unit obtains the correction output using a result obtained by approximating a distribution of the output of the light receiving unit by a distribution function including a component representing a Fresnel reflection characteristic.   The optical characteristic measurement apparatus according to claim 4, wherein the distribution function includes an amount of angular deviation between the measurement sample surface and a measurement reference surface as a parameter. The optical characteristic calculator determines the distribution function so that a difference between an output of each light receiving element and an integrated value obtained by integrating the distribution function in an integration section corresponding to each light receiving element is minimized,
The amount of angular deviation in the determined distribution function is set to 0, and a correction distribution function indicating the correction output is obtained,
The optical characteristic measuring apparatus according to claim 5, wherein the optical characteristic is derived by integrating the correction distribution function in a predetermined integration interval.   The optical property measurement apparatus according to claim 1, wherein the Fresnel reflection property is calculated using a refractive index corresponding to the measurement sample.   The optical property measurement device according to claim 7, wherein the optical property calculation unit estimates the refractive index based on an output of the light receiving unit.   The optical characteristic measuring apparatus according to claim 7, further comprising a refractive index input unit, wherein the refractive index is a refractive index input by the refractive index input unit. The distribution function includes a refractive index of the measurement sample as a parameter,
The optical characteristic measurement device according to claim 4, wherein the optical characteristic calculation unit optimizes the refractive index of the measurement sample when approximating the distribution of the output of the light receiving unit by the distribution function.   The optical characteristic measurement device according to claim 1, wherein the optical characteristic calculation unit derives the optical characteristic based on a correction output in a predetermined clipping range among the correction outputs.   The optical characteristic measuring apparatus according to claim 11, wherein the cut-out range is in the vicinity of a portion having the maximum intensity in the output of the light receiving unit. An optical property measurement method for irradiating a measurement sample with light and deriving an optical property based on an output of reflected light reflected by the measurement sample.
A method for measuring an optical characteristic, comprising: obtaining a corrected output obtained by correcting the output of the reflected light based on a Fresnel reflection characteristic, and deriving the optical characteristic based on the corrected output.

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