JP6551094B2 - Colorimeter - Google Patents

Description

  The present invention relates to a colorimeter that measures the color of an object.

  Conventionally, a halogen lamp and a xenon flash lamp are used as a light source of a colorimeter. The light emitted from the halogen lamp has a gentle spectrum from the wavelength region of visible light (also referred to as the visible light region) to the wavelength region of near infrared light (also referred to as the near infrared light region). In addition, light emitted from the xenon flash lamp has a spectrum relatively close to that of sunlight, and the spectrum is substantially constant in the wavelength range of near-ultraviolet light, visible light and infrared light. And includes a number of emission lines. That is, the light emitted from the halogen lamp and the xenon flash lamp has a radiation intensity also in the wavelength region of infrared light (also referred to as infrared light region) in addition to the visible light region used for measurement.

  On the other hand, for the sensor of the colorimeter, for example, a silicon photodiode is generally used as a photoelectric conversion element for detecting light in the visible light range. The silicon photodiode is sensitive to light of a wide wavelength band of about 300 to 1200 nm, and detects not only visible light but also infrared light. Therefore, in the colorimeter, infrared light emitted from the light source is reflected or transmitted by the object to be measured, and is detected by the silicon photodiode. At this time, the output corresponding to the spectral spectrum of the infrared light region as stray light is added to the output corresponding to the spectral spectrum of the visible light region to be originally measured. For this reason, infrared light needs to be removed in some way.

  Therefore, when a halogen lamp or a xenon flash lamp is used as a light source, generally, a filter (also referred to as an infrared cut filter) for suppressing the passage of infrared light is inserted in the illumination system or the light receiving system (for example, Patent Document 1). Thereby, the measurement result can be designed so that the influence of infrared light does not occur.

  By the way, in recent years, a configuration (also referred to as a white LED) that emits white light in response to light emission of an LED is frequently used as a light source of a colorimeter (for example, Patent Document 2). White LEDs are long-lived for light sources such as halogen lamps and xenon flash lamps, and do not have complex circuits such as trigger circuits and booster circuits as compared to xenon flash lamps. For this reason, by adopting the white LED, for example, the management of the light source becomes easy by prolonging the life of the light source, and miniaturization of the colorimeter and power saving can be realized, and a small light emitting area close to a point light source Makes it easy to illuminate with parallel light beams.

  As a system which mixes the light of a several color in order to emit white light in white LED, it is divided roughly into three types of systems, for example. The three types of methods are a method of mixing three colors of RGB light emitted from a single color LED of [i] RGB, and [ii] emission by light of blue LED and excitation of yellow phosphor by the light And (iii) a method of mixing the light of the purple LED and the three colors of RGB light emitted by the excitation of the RGB phosphor by the light. The light emitted from the white LED of any of these three types has a radiation intensity only in the visible light range, and the radiation intensity in the infrared light range is almost zero. For this reason, in the silicon photodiode, the problem that the output according to the spectrum of the infrared light region is originally added to the output according to the spectrum of the visible light region to be originally measured does not occur. That is, it is not necessary to arrange the infrared cut filter in the colorimeter.

JP 2007-192749 A JP 2005-257374 A

  By the way, some measurement objects include a fluorescent material which is excited by irradiation of visible light and emits near-infrared light. When such an object to be measured is used, infrared light emitted by fluorescence from the object to be measured is mixed into visible light even if the light emitted from the light source does not contain infrared light. Light is received by a silicon photodiode.

  In addition, for example, regardless of the method of directly reading the tristimulus values for the light from the measurement object and the method of measuring and measuring the light from the measurement object (also referred to as spectral colorimetry method), the sensor is red. In many cases, it has sensitivity to the outside light range.

  However, when the object to be measured is illuminated by a light source having no light emission intensity in the infrared light region such as a white LED, and the object to be measured reflects and transmits only light in the wavelength region of the illumination light The infrared light does not mix in the incident light to the sensor. In this case, the sensor does not cause a problem that the output corresponding to the spectral spectrum in the infrared light region is added to the output corresponding to the spectral spectrum in the visible light region to be originally measured.

  However, if the inside of the measurement object contains a fluorescent material that emits visible light as excitation light and emits infrared light as fluorescent light, infrared light is mixed in the visible light incident on the sensor. The output proportional to the amount of the infrared light is added, resulting in a decrease in colorimetric accuracy.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a color measurement technique with high color measurement accuracy.

In order to solve the above problems, the colorimeter according to the first aspect does not include infrared light and a measurement unit having a measurement opening in which a color measurement object is disposed to face and visible light passes. A light emitting unit that emits light toward the measurement opening; a light receiving unit that receives light from the measurement opening and obtains an electrical signal by photoelectric conversion; and an optical path extending from the measurement opening to the light receiving unit A first infrared light cutting portion for suppressing the passage of infrared light, and the light emitting portion disposed on a light source emitting light including infrared light, and an optical path from the light source to the measurement aperture And a second infrared light cutting portion that suppresses the passage of infrared light, and the spectral responsivity of the visible light wavelength range is heavy on the optical path from the light emitting portion to the light receiving portion. It has a filter which approximates to a coefficient, and the light receiving portion comprises a first light receiving portion and a second light receiving portion. And a third light receiving unit, wherein the filter causes a film that approximates the spectral responsivity of the visible light wavelength range to a weight coefficient x (λ) on the optical path from the measurement aperture to the first light receiving unit. And a film that causes the spectral responsivity of the visible light wavelength range to approximate to a weight coefficient y (λ) on the optical path from the measurement aperture to the second light receiving unit. A second filter including a second filter, the first filter including a film which makes the spectral responsivity of the visible light wavelength range approximate to a weight coefficient z (λ) on an optical path from the measurement aperture to the third light receiver Stimulus value direct-reading colorimeter including

The colorimeter according to the second aspect is the colorimeter according to the first aspect, wherein each of the first infrared light cut unit and the second infrared light cut unit includes an interference film . It contains.

The colorimeter according to the third aspect is the colorimeter according to the first or second aspect, wherein the filter includes an interference film.

The colorimeter according to any one of the first to third aspects suppresses the incidence of infrared light on the light receiving section, so that the output according to the spectrum of the infrared light region is the visible light that it is desired to measure. It is difficult for problems to be added to the output corresponding to the spectral spectrum of the region. Therefore, a color measurement technique with high color measurement accuracy can be provided.

According to the colorimeter according to the first aspect, although infrared light is reduced on the light emitting unit side, even when infrared light is generated due to fluorescence or the like in the sample, the light receiving unit The incidence of infrared light may be reduced.

Even with the colorimeter according to any one of the first to third aspects, even if it is a stimulus value direct reading type colorimeter, the colorimetric accuracy can be improved.

It is a figure which illustrates the schematic structure of the colorimeter which concerns on one Embodiment. It is a figure which shows an example of the spectrum of the white light emitted from white LED. It is a figure which shows an example of the spectrum of light emitted from a halogen lamp. It is a figure which shows an example of the spectrum of the light emitted from a xenon flash lamp. It is a figure which shows an example of the spectral transmission factor of LVF. It is a figure which shows an example of the spectral sensitivity of a silicon photodiode. It is a figure which illustrates the spectrum of the light emitted from an orange sample according to irradiation of visible light. It is a figure which illustrates the spectrum of the light emitted from a red sample according to irradiation of visible light. It is a figure which shows an example of the spectral transmission factor of an infrared cut filter. It is a figure which shows an example of the spectral transmission factor of an infrared cut filter. It is a figure which shows the reference example of the measurement result of the spectral reflectance which concerns on an orange sample. It is a figure which shows the reference example of the measurement result of the spectral reflectance which concerns on a red sample. It is a figure which illustrates the measurement result of spectral reflectance concerning an orange sample. It is a figure which illustrates the measurement result of the spectral reflectance which concerns on a red sample. It is a figure which illustrates the rough composition of the colorimeter concerning the 1st modification. It is a figure which shows one structural example of the light reception system which concerns on a 2nd modification. It is a figure which illustrates a schematic structure of the colorimeter which concerns on a 3rd modification. It is a figure which shows one structural example of the light-receiving system of the colorimeter which concerns on a 4th modification. It is a figure which illustrates the spectral sensitivity of three sensors of the color value meter of a stimulus value direct reading system. It is a figure which illustrates the schematic structure of the colorimeter which concerns on a 5th modification. It is a figure which illustrates the schematic structure of the colorimeter which concerns on a 6th modification.

  Hereinafter, an embodiment and various modifications of the present invention will be described based on the drawings. In the drawings, portions having similar configurations and functions are denoted by the same reference numerals, and redundant description will be omitted in the following description. Further, the drawings are schematically illustrated, and the sizes and positional relationships of various structures in the drawings are not exactly illustrated.

<(1) One Embodiment>
<(1-1) Schematic Configuration of Colorimeter>
FIG. 1 is a diagram illustrating a schematic configuration of a colorimeter 1 according to an embodiment.

  The colorimeter 1 includes an illumination system 10, a light reception system 20, a control unit 30, and a calculation unit 40 in a housing 2.

  The housing 2 is, for example, a box-shaped case that covers various configurations of the colorimeter 1 from the outside. The housing 2 is provided with a measurement unit 2hp for measuring the color of the surface of the color measurement object Sm1. The measurement portion 2hp is provided with a measurement opening 2h through which visible light passes. The measurement opening 2h allows visible light emitted from the illumination system 10 in the housing 2 to pass through in a state where the colorimetric object Sm1 is disposed so as to face the measurement opening 2h, thereby allowing the visible light to pass. Is irradiated to the color measurement object Sm1. At this time, the measurement aperture 2 h passes light generated on the surface of the color measurement object Sm1 in response to the irradiation of visible light, and causes the light receiving system 20 to receive light. The measurement opening 2h may be, for example, a hole where no member is disposed, or may be a portion where a transparent member capable of passing visible light is disposed. The transparent member may be made of, for example, a transparent material such as glass or acrylic.

  The illumination system 10 includes a light emitting unit 11, a collimator lens 12, and a light emitting circuit 13.

  The light emitting unit 11 irradiates light that does not include infrared light toward the measurement opening 2h. For this reason, when the colorimetric object Sm1 is disposed facing the measurement opening 2h, the colorimetric object Sm1 is irradiated with light that does not include infrared light. The infrared light is, for example, light in a wavelength range of 780 to 1200 nm. Here, if the light emitting unit 11 includes, for example, a light source that emits white light by a light emitting diode (LED), it is possible to facilitate management, miniaturize the colorimeter, and save power, for example. In addition, for example, since light is emitted from a narrow area such as a point light source or the like, illumination by parallel light beams becomes easy. This can improve the measurement accuracy.

  In addition, as a structure (it is also called white LED) which emits white light by LED, the 1st-3rd white LED of 3 systems may be employ | adopted, for example. The first white LED has a configuration that emits white light by mixing light of three colors of RGB emitted from single color LEDs of three colors of RGB. The second white LED is configured to mix the light of the blue LED and the yellow light emitted by the excitation of the yellow phosphor by the light. The third white LED has a configuration in which the light of the violet LED is mixed with the RGB light emitted by the excitation of the RGB phosphor by the light.

  The collimator lens 12 converts the light emitted from the light emitting unit 11 into parallel light toward the measurement object Sm1. At this time, light is irradiated to the colorimetric object Sm1 at a predetermined angle set in advance.

  The light emitting circuit 13 controls the timing at which the light emitting unit 11 emits light in accordance with a signal from the control unit 30.

  The light receiving system 20 receives light from the measurement opening 2h at a predetermined angle set in advance. For this reason, when the colorimetric object Sm1 is arranged facing the measurement opening 2h, the light emitted mainly by reflection from the colorimetric object Sm1 is at a predetermined angle set in advance by the light receiving system 20. Received light. The light receiving system 20 includes an objective lens 21, a light guide unit 22, and a light receiving system main body 20b.

  The objective lens 21 is a lens that guides light emitted from the colorimetric object Sm1 to the light guide unit 22. Here, the light emitted from the color measurement object Sm1 is light to be measured (also referred to as light to be measured).

  The light guide 22 guides the light to be measured emitted from the color measurement object Sm1 into the light receiving system main body 20b. The light guide 22 is configured to include, for example, an optical fiber.

  The light receiving system main body 20b has, for example, a substantially cylindrical housing, and in the housing, an infrared light cut unit 23, imaging lenses 24 and 25, a collimator lens 26, a spectroscopic unit 27, and a light receiving unit. 28.

  The infrared light cutting unit 23 suppresses the passage of infrared light. The infrared light cut portion 23 is disposed on the optical path from the measurement aperture 2 h to the light receiving portion 28.

  The spectroscopic unit 27 divides the visible light of the measurement light incident from the collimator lens 26. For example, a linear variable filter (LVF) or the like is adopted as the light separating unit 27. The LVF is, for example, a filter in which the wavelength of transmitted light changes as the position where the measured light passes is shifted in one direction (also referred to as a wavelength change direction). Specifically, the light to be measured incident on the spectroscopic unit 27 is decomposed into different monochromatic lights according to the position in the wavelength change direction by the LVF, received by the light receiving unit 28, and converted into an electrical signal by photoelectric conversion. Is done. For example, when the LVF is employed as the spectroscopic unit 27, the colorimeter 1 can be downsized by downsizing the configuration for splitting visible light.

  The spectroscopic unit 27 is disposed on the optical path from the measurement aperture 2 h to the light receiving unit 28. Specifically, the light to be measured emitted from the colorimetric object Sm1 and transmitted through the objective lens 21, the light guide unit 22, the infrared light cut unit 23, the imaging lenses 24 and 25, and the collimator lens 26 is spectrally separated. Spectroscopy by the unit 27.

  The imaging lenses 24 and 25 guide the light to be measured, which is incident on the light receiving system main body 20 b from the light guide 22 and transmitted through the infrared light cutting unit 23, to the collimator lens 26. The collimator lens 26 efficiently guides the light to be measured guided from the imaging lenses 24 and 25 to the light splitting unit 27. Here, the imaging lenses 24 and 25 and the collimator lens 26 have, for example, a relatively strong refractive power in a direction orthogonal to the LVF wavelength change direction (also referred to as LVF orthogonal direction) and in the LVF wavelength change direction, respectively. It is a cylindrical lens. Specifically, the collimator lens 26 makes the light to be measured enter the LVF in parallel. The imaging lenses 24 and 25 focus the light to be measured on the light receiving surface (also referred to as a sensor surface) of the light receiving unit 28 in the LVF orthogonal direction. Thereby, the light to be measured can be utilized to the maximum extent in the light receiving unit 28. That is, the light to be measured going from the collimator lens 26 to the LVF becomes parallel light whose cross section of the luminous flux is substantially linear.

  The light receiving unit 28 receives light from the measurement opening 2h and obtains an electric signal by photoelectric conversion. For this reason, when the colorimetric object Sm1 is arranged facing the measurement opening 2h, the colorimetric object Sm1 is emitted from the colorimetric object Sm1 in response to the light emitted from the light emitting unit 11 to the colorimetric object Sm1. Visible light is received to obtain an electrical signal by photoelectric conversion. In the present embodiment, the light receiving unit 28 splits the light to be measured into a plurality of monochromatic lights, and receives the plurality of monochromatic lights after the splitting by a plurality of sensors to obtain an electrical signal according to the intensity of the light. Yes.

  Specifically, for example, it has a form of a line sensor in which a plurality of light receiving elements are arranged in a direction corresponding to the direction in which light is split by the splitting unit 27. Thereby, in a plurality of light receiving elements, for example, light in different wavelength ranges can be received, and an electric signal corresponding to the amount of the light can be obtained by photoelectric conversion. In addition, as a some light receiving element, the silicon photodiode etc. which perform photoelectric conversion which produces an electric signal according to irradiation of light may be employ | adopted, for example.

  The calculation unit 40 obtains information related to the color of the color measurement object Sm1 by calculation based on the electrical signal obtained by the light receiving unit 28. Here, for example, calculations according to various color system calculation methods are performed. Note that the calculation in the calculation unit 40 includes, for example, a calculation in which the sensitivity of the human eye is multiplied to the obtained electric signal.

<(1-2) Arrangement of infrared cut section>
FIG. 2 is a diagram showing an example of a spectrum of white light emitted from a white LED. In FIG. 2, the horizontal axis indicates the wavelength, and the vertical axis indicates the relative intensity. In FIG. 2, the spectrum of light emitted from the first white LED is indicated by a curve drawn with a solid line, and the spectrum of light emitted from the second white LED is indicated by a curve drawn with a broken line. The spectrum of the light emitted from the third white LED is shown by a curve drawn by a dashed dotted line. As shown in FIG. 2, the light emitted from each white LED of the first to third white LEDs is constituted by a component of visible light and is substantially free of a component of infrared light.

  On the other hand, FIG. 3 is a diagram showing an example of a spectrum of light emitted from a halogen lamp. FIG. 4 is a diagram illustrating an example of a spectrum of light emitted from a xenon flash lamp. 3 and 4, the horizontal axis indicates the wavelength, and the vertical axis indicates the relative intensity. In FIG. 3, the spectrum of light emitted from the halogen lamp is shown by a curve drawn by a solid line, and in FIG. 4, the spectrum of light emitted from a xenon flash lamp is shown by a curve drawn by a solid line. ing. As shown in FIGS. 3 and 4, not only visible light but also infrared light is emitted from both the halogen lamp and the xenon flash lamp.

  FIG. 5 is a diagram showing an example of the spectral transmittance of the LVF that constitutes the spectral unit 27. As shown in FIG. In FIG. 5, the horizontal axis indicates the wavelength, and the vertical axis indicates the transmittance. In FIG. 5, the transmittance in a portion that transmits light with a wavelength of 390 nm is shown by a solid line, and the transmittance in a portion that transmits light with a wavelength of 560 nm is shown by a curve drawn by a broken line. Has been. As shown in FIG. 5, in the visible light range, light of the designed wavelength is transmitted, and transmission of light of other wavelengths is substantially completely blocked. On the other hand, it is difficult to design an interference film so as to substantially block all light in a wide wavelength range from the ultraviolet light range to the infrared light range. For example, in a portion of the LVF which transmits light of a wavelength of 390 nm, infrared light of a wavelength range of 800 nm or more is also transmitted.

  FIG. 6 is a diagram illustrating an example of the spectral sensitivity of the silicon photodiode constituting the light receiving unit 28. In FIG. 6, the horizontal axis indicates the wavelength, and the vertical axis indicates the sensitivity. As shown in FIG. 6, silicon photodiodes have strong sensitivity to infrared light as well as sensitivity to the visible light range.

  Here, assuming a colorimeter in which halogen lamps and xenon flash lamps are used as light sources, visible light and infrared light emitted from the light sources are reflected by the colorimetric object and detected by a silicon photodiode. Is done. At this time, the output according to the infrared spectrum region is added to the output according to the visible spectrum region to be originally measured. Therefore, when a halogen lamp or a xenon flash lamp is used as a light source, an infrared cut filter is generally inserted into the illumination system or the light receiving system so that the measurement result is not affected by the infrared light.

  On the other hand, in a colorimeter in which a white LED is used as a light source, substantially no infrared light is emitted from the light source, visible light emitted from the white LED is reflected by the colorimetric object, and is detected by a silicon photodiode. Detected. For this reason, it is difficult to assume that the measurement result is affected by infrared light. Therefore, in the silicon photodiode, there is no problem that the output corresponding to the spectral spectrum in the infrared light region is added to the output corresponding to the spectral spectrum in the visible light region to be originally measured. That is, it is not necessary to arrange the infrared cut filter in the colorimeter.

  However, there are samples containing a fluorescent substance that is excited by irradiation with visible light to generate near infrared light by fluorescence. FIG. 7 is a diagram illustrating a spectrum of light emitted from an orange sample (also referred to as a first sample) in response to irradiation with visible light. FIG. 8 is a diagram illustrating a spectrum of light emitted from a red sample (also referred to as a second sample) in response to irradiation with visible light.

  In FIGS. 7 and 8, the horizontal axis indicates the wavelength, and the vertical axis indicates the relative light amount (corresponding to the relative intensity). In FIGS. 7 and 8, the spectrum of light emitted from the sample in response to irradiation with 400 nm light is shown by a curve drawn in bold lines, and emitted from the sample in response to irradiation with 450 nm light. The spectrum of light is shown by the dashed curve, and the spectrum of light emitted from the sample in response to the 500 nm light is shown by the dashed line. In FIGS. 7 and 8, the spectrum of light emitted from the sample in response to irradiation with light at 550 nm is shown by a curve drawn with a two-dot chain line, and emitted from the sample in response to irradiation with light at 600 nm. The spectrum of the emitted light is shown by a thin-lined curve.

  As shown in FIG. 7 and FIG. 8, for example, when light of 400 nm is irradiated on the sample, the spectral spectrum of the light emitted from the sample includes, in addition to the relative light amount in the visible light region near 400 nm, It can be seen that the relative light quantity in the near-infrared light region around 700 to 1050 nm was mixed. Such a phenomenon means that the sample contains a fluorescent material that emits light in the near-infrared light region near 850 nm by using visible light of 400 nm as excitation light. As shown in FIGS. 7 and 8, the wavelength range of visible light acting as excitation light is estimated to cover a wavelength range of about 400 to 600 nm. That is, it is presumed that the first and second samples contain a fluorescent material that emits light in the near-infrared light region by using visible light of about 400 to 600 nm as excitation light.

  When the first and second samples containing a fluorescent material that emits light in the near-infrared region in response to irradiation with such visible light are used as a colorimetric object, the light emitted from the light source is infrared. Even if light is not contained, near infrared light due to fluorescence is mixed in visible light emitted from the object to be measured. At this time, when light in which near-infrared light is mixed with visible light is received by a silicon photodiode as a sensor, the spectral spectrum of the infrared light region is output to the output corresponding to the spectral spectrum of the visible light region to be originally measured. The output corresponding to is added, which leads to a decrease in colorimetric accuracy.

  Therefore, in the colorimeter 1 according to the present embodiment, the red light on the light path from the measurement opening 2 h to the light receiving unit 28 is used to suppress the incidence of infrared light generated by the color measurement object Sm1 on the light receiving unit 28. The ambient light cutting portion 23 is disposed. Here, the infrared light cut for reducing the passage of infrared light (also referred to as infrared light cut) is, for example, an intensity of at least several percent or 1% or less of infrared light in a wavelength region of 780 to 1200 nm. Means to reduce. For example, it is only necessary that the infrared light in the wavelength region of about 850 nm is significantly reduced.

  As the infrared light cut unit 23, for example, a film generated by depositing an interference film is employed. Further, as the infrared light cut portion 23, an optical component having other functions such as a lens, a prism, an optical filter, and the like, on which an interference film for cutting infrared light is deposited may be employed. . Thereby, various configurations having the property of suppressing the transmission of infrared light can be realized. Further, for example, the function of the infrared light cut unit 23 may be realized by inserting a glass filter having a property of absorbing infrared light in the optical path instead of the interference film. In addition, for example, by adopting an infrared light cut portion 23 formed by depositing an interference film having a function of cutting infrared light on the surface of a filter that absorbs infrared light, infrared light is adopted. The colorimetric accuracy of the colorimeter 1 may be improved by further reducing the transmittance of the colorimeter 1.

  FIG. 9 and FIG. 10 are diagrams illustrating the spectral transmittance of the infrared cut filter as the infrared light cut portion 23. In FIG. 9, the spectral transmittance of the interference film as the infrared light cut portion 23 is shown, and in FIG. 10, the spectral transmittance of the glass filter having the property of absorbing infrared light as the infrared light cut portion 23 is It is shown.

  As shown in FIG. 9, the interference film as the infrared cut filter transmits, for example, visible light having a wavelength of about 370 to 780 nm and reflects infrared light having a wavelength of about 780 to 1100 nm. As shown in FIG. 10, the glass filter as the infrared cut filter transmits, for example, visible light having a wavelength of about 370 to 780 nm and absorbs infrared light having a wavelength of about 780 to 1100 nm. By these actions, it is possible to suppress the loss of light in the visible light region to be measured low and to eliminate unnecessary infrared light.

  FIG. 11 is a diagram showing an example of the measurement result of the spectral reflectance of the orange first sample as the color measurement object Sm1. FIG. 12 is a view showing an example of the spectral reflectance of the second sample of red as the color measurement object Sm1. 11 and 12, the horizontal axis indicates the wavelength, and the vertical axis indicates the reflectance. In FIGS. 11 and 12, the measured values of the spectral reflectance obtained by the configuration in which the infrared light cut unit 23 is temporarily removed from the colorimeter 1 are shown by curves drawn with broken lines. Further, in FIGS. 11 and 12, the true spectral reflectance when the infrared light component generated by the fluorescence is removed is shown by a curve drawn with a solid line.

  As shown in FIGS. 11 and 12, in the relatively short wavelength range of 400 to 500 nm in the visible light range, the actual measured value of the spectral reflectance is clearly higher than the true spectral reflectance. Presented. Here, the light receiving unit 28 that receives light in a relatively short wavelength range of 400 to 500 nm has spectral sensitivity even in the infrared light range, and the light receiving unit 28 relates to visible light from the color measurement object Sm1. The output related to the infrared light from the colorimetric object Sm1 can be superimposed on the output. At this time, it can be seen that the reflectance can be increased by about 25% at maximum with respect to the true spectral reflectance. The amount of spectral reflectance shift is quite large and cannot be overlooked.

  On the other hand, when the infrared light cut unit 23 is provided as in the colorimeter 1 according to the present embodiment, the difference between the measured value of the spectral reflectance and the true spectral reflectance is Almost disappear.

  FIG. 13 is a diagram showing an example of the measurement result of the spectral reflectance of the orange first sample as the color measurement object Sm1. FIG. 14 is a view showing an example of the spectral reflectance of the second sample of red as the color measurement object Sm1. In FIGS. 13 and 14, the horizontal axis indicates the wavelength, and the vertical axis indicates the reflectance. In FIGS. 13 and 14, the actual measured value of the spectral reflectance acquired by the colorimeter 1 having the infrared light cut unit 23 is shown by a curve drawn with a broken line. Moreover, in FIG. 13 and FIG. 14, the true spectral reflectance when the component of the infrared light by fluorescence is removed is shown by the curve drawn with the continuous line.

  As shown in FIG. 13 and FIG. 14, the actual measured values of the spectral reflectance exhibited almost the same value as the true spectral reflectance. That is, the measured value of the spectral reflectance had a value substantially the same as the true spectral reflectance. In this case, the presence of the infrared light cut portion 23 suppresses the incidence of the infrared light generated by the fluorescence on the light receiving portion 28. For this reason, it is hard to produce the malfunction that the output according to the spectral spectrum of an infrared light region is added to the output according to the spectral spectrum of the visible light region to measure originally.

<(1-3) Summary of one embodiment>
As described above, according to the colorimeter 1 according to the embodiment, the infrared light cutting unit 23 is disposed on the optical path from the measurement opening 2 h to the light receiving unit 28. As a result, the incidence of the infrared light generated in the color measurement target Sm1 on the light receiving unit 28 is suppressed. For this reason, in the light receiving unit 28, it is difficult to cause a problem that an output according to the spectrum of the infrared light region is added to an output according to the spectrum of the visible light region to be originally measured. Therefore, a color measurement technique with high color measurement accuracy can be provided.

<(2) Modification>
Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the gist of the present invention.

<(2-1) First Modification>
In the above embodiment, light emitted mainly by reflection from the color measurement object Sm1 is received by the light receiving system 20 at a predetermined angle set in advance, but the present invention is not limited to this. For example, light emitted by mainly transmitting the color measurement target Sm1 in response to irradiation of light from the light emitting unit 11 may be received by the light receiving system 20 at a predetermined angle set in advance. That is, for example, the light receiving unit 28 may be any unit as long as it receives light emitted from the color measurement object Sm1 in response to the irradiation of light by the light emitting unit 11 and obtains an electric signal by photoelectric conversion. Here, a specific example of the colorimeter 1A according to the first modification will be described.

  FIG. 15 is a diagram illustrating a schematic configuration of a colorimeter 1A according to the first modification. As shown in FIG. 15, the colorimeter 1 </ b> A according to the first modification is based on the colorimeter 1 according to the above-described embodiment, and the housing 2 has a lighting system 10. 2a and a second housing 2b having a light receiving system 20.

  The first housing 2a is provided with a first measurement unit 2hpa for measuring the color of the color measurement object Sm1. The first measurement section 2hpa is provided with a first measurement opening 2ha through which visible light passes. In addition, a second measurement unit 2 hpb for measuring the color of the color measurement object Sm1 is provided in the second housing 2 b. The second measurement section 2hpb is provided with a second measurement opening 2hb through which visible light passes. When measuring the color of the colorimetric object Sm1, the colorimetric object Sm1 is arranged at a position sandwiched between the first measuring unit 2hpa and the second measuring unit 2hpb.

  And in the state where the first measurement opening 2ha is disposed so as to face the first measurement opening 2ha, the visible light emitted from the illumination system 10 in the first housing 2a is The visible light is emitted to the color measurement object Sm1 by passing the light. At this time, the second measurement aperture 2 hb causes light passing through the color measurement object Sm 1 to pass through the second measurement aperture 2 hb according to the irradiation of visible light and causes the light receiving system 20 to receive the light. For this reason, also in the colorimeter 1A according to the first modification, as in the colorimeter 1 according to the one embodiment, the light from the infrared light cutting unit 23 extends from the second measurement opening 2hb to the light receiving unit 28. Located on the street. Therefore, in the colorimeter 1A according to the present modification, the same effect as the colorimeter 1 according to the embodiment is obtained.

<(2-2) Second Modification>
In the one embodiment and the first modified example, the spectroscopic unit 27 is configured by LVF, but is not limited thereto. For example, the light receiving system 20 may be replaced by the light receiving system 20B by replacing the light receiving system main body 20b having the light separating unit 27 with the light receiving system main body 20bB including the light separating unit 27B configured by the diffraction grating. . Even if such a configuration is adopted, a colorimetric technique with high colorimetric accuracy can be easily provided. Here, a specific example of the light receiving system main body 20bB according to the second modification in which such a configuration is adopted will be described.

  FIG. 16 is a diagram illustrating a configuration example of the light receiving system main body 20bB according to the second modification. As shown in FIG. 16, the light receiving system main body 20bB has, for example, a substantially rectangular parallelepiped housing, and the infrared light cut portion 23, the spectroscopic portion 27B, and the light receiving portion 28 are provided in the housing. doing.

  The infrared light cut portion 23 is provided on the optical path of the light to be measured that is introduced into the light receiving system main body portion 20bB through the slit portion 20SL guided by the light guide portion 22 and provided in the housing. And the to-be-measured light which passed the infrared-light cut part 23 is irradiated to the spectroscopy part 27B.

  The spectral unit 27B is configured to include, for example, a diffraction grating or the like, and disperses visible light of the measurement light incident from the infrared light cutting unit 23. In the light separating section 27B, the light to be measured diffracted by the diffraction grating is split such that the wavelength changes in one direction of magnitude as the light shifts in one direction. Further, the spectroscope unit 27B is disposed on the optical path from the measurement aperture 2h (or the second measurement aperture 2hb) to the light receiving unit 28. As a result, the light to be measured which is emitted from the color measurement object Sm1 and transmitted through the infrared light cut portion 23 is split into a plurality of single color lights by the light splitting portion 27B.

  As described above, the light receiving system main body 20bB according to the second modification has a configuration in which the infrared light cut unit 23 is arranged in the polychromator.

  By the way, when the light to be measured includes infrared light, if the infrared light cut portion 23 is not provided, the infrared light is reflected by the inner wall portion of the housing of the light receiving system main body portion 20bB. The light receiving unit 28 can be irradiated with infrared light. On the other hand, in the present modification shown in FIG. 16, the passage of the light in the infrared light region included in the light to be measured incident on the light receiving system main body 20 b B is suppressed by the infrared light cutting portion 23. As a result, it becomes difficult for the light receiving unit 28 to be irradiated with infrared light, and the color measurement accuracy in the colorimeter 1 B can be improved.

<(2-3) Third Modification>
In the above-described embodiment and the first and second modified examples, light not including infrared light is emitted to the color measurement object Sm1 by the light emitting unit 11 to which the white LED is applied, but the present invention is not limited thereto. . For example, the light emitting unit 11 is a light source that emits light including infrared light, and red that is disposed on the light path from the light source toward the measurement aperture 2 h (or the first measurement aperture 2 ha) and suppresses the passage of infrared light A configuration including an external light cut portion may be employed. At this time, the infrared light cut portion is provided not only on the optical path from the second measurement opening 2hb toward the light receiving portion 28 but also on the light emitting portion.

  In such a configuration, the infrared light to the light receiving unit 28 is generated even when the infrared light is generated due to the fluorescence or the like in the measurement object Sm1 although the infrared light is reduced on the light emitting unit side. Incidence can be reduced. In addition, as a light source which emits the light containing infrared light, a halogen lamp, a xenon flash lamp etc. are employ | adopted, for example. Further, as the infrared light cut portion, for example, one having a configuration similar to that of the above-described infrared light cut portion 23 may be employed. Here, a specific example of a colorimeter according to a third modification in which such a configuration is adopted will be described by way of example.

  FIG. 17 is a diagram illustrating a schematic configuration of a colorimeter 1C according to the third modification. As shown in FIG. 17, the colorimeter 1C according to the third modification is based on the colorimeter 1 according to the above-described embodiment, and the light emitting unit 11 is replaced with the light emitting unit 11C. The illumination system 10 is changed to the illumination system 10C.

  The light emitting unit 11C includes a light source 11Ca, a back reflection member 11Cb, and an infrared light cutting unit 11Cc. The light source 11Ca is configured to include a halogen lamp, a xenon flash lamp, and the like, and emits light including infrared light. The back surface reflection member 11Cb is a concave reflection member arranged to cover the back surface of the light source 11Ca. The infrared light cut portion 11Cc is, for example, arranged to cover the opening of the back surface reflection member 11Cb. As the infrared light cut portion 11Cc, one having the same configuration and function as the infrared light cut portion 23 of the one embodiment may be employed. With such a configuration, the light emitted from the light source 11Ca is reflected directly or by the back reflecting member 11Cb and applied to the infrared light cut portion 11Cc arranged in the opening of the back reflecting member 11Cb. At this time, when light passes through the infrared light cut portion 11Cc, infrared light contained in the light emitted from the light source 11Ca can be reduced. Then, light that does not contain infrared light is emitted from the light emitting unit 11C, and the light can be irradiated to the color measurement target Sm1 via the collimator lens 12 and the measurement aperture 2h.

  When such a configuration is employed, for example, a configuration in which the measurement unit 2hp is an integrating sphere and the measurement aperture 2h is provided in the integrating sphere may be employed. In this case, for example, the light irradiated from the illumination system 10C into the integrating sphere is reflected in the integrating sphere and irradiated onto the colorimetric object Sm1 through the measurement aperture 2h, and at that time, from the colorimetric object Sm1 Light emitted and incident into the integrating sphere through the measurement aperture 2 h may be reflected in the integrating sphere and received by the light receiving system 20.

<(2-4) 4th modification>
In the above embodiment and the first to third modifications, the light receiving system 20, 20B is adopted in which the light separated by the light separating parts 27, 27B is received by the light receiving part 28 having the form of a line sensor. Not limited to. For example, a light receiving system 20D of a system (also referred to as a stimulation value direct reading system) of measuring tristimulus values of X, Y and Z using a sensor corresponding to the spectral sensitivity of human eyes may be employed. That is, a stimulus value direct-reading colorimeter may be employed. Here, a specific example of the light receiving system 20D according to the fourth modification in which such a configuration is adopted will be described.

  FIG. 18 is a diagram illustrating a configuration example of the light receiving system 20D according to the fourth modification. As shown in FIG. 18, three sensors as three light receiving portions 28a to 28c are provided, a filter F1a is provided on the front surface of the light receiving portion 28a, and a filter F1b is provided on the front surface of the light receiving portion 28b. A filter F1c is provided on the front surface of the light receiving unit 28c. Here, silicon photodiodes may be employed as the three sensors, for example.

  In the stimulus value direct reading light receiving system 20D, for example, a filter F1a that approximates the spectral response in the wavelength range of visible light to the weight coefficient on the optical path from the light emitting unit 11 (11C) to the light receiving units 28a to 28c. -F1c should just be provided. The filter may be an interference film, or may be a glass filter or the like. For example, the function of the filters F1a to F1c may be realized by inserting a laminate of glass filters having different properties of absorbing light into the light path. Furthermore, for example, instead of the interference film, a film of any material such as a gelatin film and an acetate film may be employed.

  Specifically, the light receiving system 20D obtains the first light receiving unit 20Da for obtaining the stimulation value X among the three stimulation values X, Y, Z, and the second for obtaining the stimulation value Y among the three stimulation values X, Y, Z. A light receiving unit 20Db and a third light receiving unit 20Dc for obtaining a stimulation value Z among the three stimulation values X, Y and Z are provided.

  For example, in the first light receiving unit 20Da, an interference film 29a whose spectral response is approximated to the weight coefficient x (λ) is deposited on the surface of the filter F1a, so that the tristimulus values X, Y, and Z And an interference film as an infrared light cut portion 23a for cutting infrared light is deposited on the back surface of the filter F1a. In this case, for example, the interference film 29a and the infrared light cut portion 23a may be provided so that the spectral response of the entire colorimeter is approximated to the weight coefficient x (λ).

  Further, in the second light receiving unit 20Db, the interference film 29b whose spectral responsivity is approximated to the weight coefficient y (λ) is vapor-deposited on the surface of the filter F1b, so that among the three stimulation values X, Y, Z The stimulation value Y is obtained, and an interference film may be deposited on the back surface of the filter F1b as an infrared light cut portion 23b for cutting infrared light. In this case, for example, the interference film 29 b and the infrared light cut portion 23 b may be provided so that the spectral responsivity of the entire colorimeter is approximated to the weight coefficient y (λ).

  Further, in the third light receiving unit 20Dc, the interference film 29c whose spectral responsivity is approximated to the weight coefficient z (λ) is vapor-deposited on the surface of the filter F1c, and among the three stimulus values X, Y, Z The stimulation value Z is obtained, and an interference film may be deposited on the back surface of the filter F1c as an infrared light cut portion 23c that cuts infrared light. In this case, for example, the interference film 29 c and the infrared light cut portion 23 c may be provided so that the spectral responsivity of the entire colorimeter approximates to the weight coefficient z (λ).

  FIG. 19 is a diagram showing an example of the spectral sensitivity in each light receiving unit when the first to third light receiving units 20Da to 20Dc are not provided with the infrared light cutting portions 23a to 23c. In FIG. 19, the horizontal axis indicates the wavelength, and the vertical axis indicates the sensitivity. The spectral sensitivity of the light receiving unit relating to the stimulation value X is indicated by a curve drawn by a solid line, and the spectral sensitivity of the light receiving unit relating to the stimulation value Y is shown by a curve drawn by an alternate long and short dash line The spectral sensitivity of the light receiving unit is indicated by a curve drawn by a broken line.

  As shown in FIG. 19, each light receiving unit has strong sensitivity to infrared light as well as sensitivity to the visible light range. That is, in each light receiving unit, in the visible light region, the degree of coincidence with the valence coefficient is high, while in the infrared light region, a film in which wide-band light is cut to about 1200 nm with sensitivity to silicon photodiodes Design is difficult. In FIG. 19, it also has sensitivity to light in a part of infrared light region in a wavelength region of about 950 to 1200 nm. Therefore, in the stimulation value direct reading type light receiving system 20D, for example, the infrared light cutting parts 23a to 23c are disposed on the optical path from the measurement aperture 2h to the light receiving parts 28a to 28c. Thereby, even in the case of the stimulus value direct reading type colorimeter, the color measurement accuracy can be enhanced.

<(2-5) Fifth Modification>
In the one embodiment and the first to third modifications, light generated in the color measurement object Sm1 in response to the irradiation of light by the illumination system 10 (10C) is the light from the spectral part 27 (27B) such as the LVF and the diffraction grating. Although spatially dispersed, it is not limited to this. For example, a configuration may be employed in which a light separating unit 27E configured to perform time-divisional light separation is provided before irradiating the light generated in the illumination system to the color measurement target Sm1. That is, for example, a spectroscopic unit that splits visible light may be provided on the optical path from the light emitting unit to the light receiving unit. According to such a configuration, the colorimetric accuracy can be enhanced even if a configuration in which visible light is split at any position on the light path from the illumination system to the light receiving unit is adopted. Here, a specific example of a colorimeter 1E according to a fifth modification in which such a configuration is adopted will be described by way of example.

  FIG. 20 is a view showing an example of the configuration of a colorimeter 1E according to a fifth modification. As shown in FIG. 20, the colorimeter 1E is based on the colorimeter 1E according to the above embodiment, and the illumination system 10, the light receiving system 20 and the calculation unit 40 are an illumination system 10E and a light receiving system 20E. And a calculating unit 40E, and further has a configuration in which a light separating unit 27E is added.

  The illumination system 10E has a configuration similar to that of the illumination system 10 according to the embodiment, but the illumination system 10E is based on the illumination system 10 according to the embodiment, and the collimator lens 12 is The light emitted from the light emitting unit 11 is replaced by a convex lens 12E for causing the light to enter the light separating unit 27E.

  The spectroscope unit 27E is configured of, for example, a monochromator, and converts white light into multiple monochromatic lights in the visible light region in a time division manner. In the spectroscopic unit 27E shown in FIG. 20, for example, the light reflected by the first reflecting unit Mr1 is irradiated to the planar diffraction grating Gr2 that is rotatably arranged, and at that time, the light is emitted from the diffraction grating Gr2. The reflected light is reflected by the second reflection part Mr2 and emitted out of the light splitting part 27E through the slit. At this time, for example, the wavelength range of the monochromatic light emitted from the spectroscopic unit 27E can be changed little by little by changing the angle defining the attitude of the diffraction grating Gr2 little by little. The angle of the diffraction grating Gr2 is controlled by the drive unit 33 based on, for example, a signal from the control unit 33.

  In this way, the monochromatic light emitted in a time-sharing manner from the spectroscopic unit 27E is converted into parallel light by, for example, the collimating lens Lz2, and irradiated to the colorimetric object Sm1 through the measurement aperture 2h. At this time, the light emitted from the color measurement object Sm1 is received by the light receiving unit 28E.

  The light receiving system 20E has an objective lens 21 having a positive power for converging a light beam, an infrared light cutting unit 23 for reducing infrared light contained in light transmitted through the objective lens 21, and a light receiving unit 28E. ing. Here, due to the presence of the infrared light cut portion 23, infrared light emitted by the fluorescence in the color measurement object Sm1 according to the irradiation of the visible light in the wavelength range of about 400 nm may be reduced. The light receiving unit 28E is formed of, for example, a silicon photodiode or the like, and outputs an electrical signal according to the amount of light simply incident on the light receiving unit 28E by photoelectric conversion for each monochromatic light.

  The calculator 40E can calculate the reflectance of the color measurement object Sm1 for each single color light according to the electric signal output from the light receiver 28E.

<(2-6) Sixth Modification>
In the above-described embodiment and the first and second modifications, for example, a light source emitting white light by an LED is adopted as the light emitting unit 11 of the illumination system 10, but the present invention is not limited thereto. For example, illumination having a light source, such as a halogen lamp and a xenon lamp, containing a component of infrared light in the emitted light, and an infrared light cutting portion disposed between the light source and the object to be measured Sm1 A system may be employed. According to such a configuration, even if the color measurement object Sm1 is discolored due to a temperature change such as a temperature increase due to the irradiation of infrared light, the color measurement object is measured due to the presence of the infrared light cut portion. Irradiation of infrared light to the object Sm1 is suppressed, and discoloration due to a temperature change of the colorimetric object Sm1 can be suppressed. Furthermore, the passage of infrared light emitted by excitation by irradiation of visible light in the colorimetric object Sm1 is suppressed by the infrared light cut unit 23 provided on the optical path from the measurement aperture 2h (2hb) to the light receiving unit 28. As a result, the luminous flux of the visible light to be measured can be input to the light receiving unit 28. Here, a specific example of a colorimeter 1F according to a sixth modification in which such a configuration is adopted will be described by way of example.

  FIG. 21 is a diagram showing an example of a configuration of a colorimeter 1F according to a sixth modification. As shown in FIG. 21, the colorimeter 1F has a configuration in which the illumination system 10 is replaced with the illumination system 10F based on the colorimeter 1 according to the above-described embodiment.

  The illumination system 10F is a system in which the light emitting unit 11 of the illumination system 10 according to the embodiment is replaced with a light emitting unit 11F. The light emitting unit 11F includes a light source unit 11Fa and an infrared light cutting unit 11Fb. The light source unit 11Fa may be, for example, a light source such as a halogen lamp and a xenon lamp, in which emitted light includes a component of infrared light. The infrared light cut portion 11Fb may be, for example, one that suppresses the passage of infrared light similarly to the infrared light cut portion 23.

<(2-7) Other modifications>
For example, although the light emitted from the illumination system 10E is dispersed by the diffraction grating Gr2 in the monochromator in the fifth modification, the invention is not limited thereto. For example, instead of the diffraction grating Gr2, the wavelength range of monochromatic light emitted from the spectroscopic unit is gradually changed by gradually changing the shift amount of the LVF arranged to be slidable in one direction. May be.

  Needless to say, all or part of the above-described one embodiment and various modifications may be combined as appropriate, as long as no contradiction arises.

1, 1A to 1F Colorimeter 2 Housing 2a 1st housing 2b 2nd housing 2h Measurement opening 2ha 1st measurement opening 2hb 2nd measurement opening 2hp Measurement unit 2hpa 1st measurement unit 2hpb 2nd measurement unit 10, 10C , 10E, 10F Illumination system 11, 11C, 11F Light emitting part 11Cc, 11Fb, 23, 23a-23c Infrared light cut part 20, 20D, 20E Light receiving system 20b, 20bB Light receiving system main body 20Da-20Dc First to third light receiving units 27, 27B, 27E Spectroscopic unit 28, 28B, 28E, 28a to 28c Light receiving unit 29a to 29c Interference film 30 Control unit 40, 40E Calculation unit F1a to F1c Filter Gr2 Diffraction grating Sm1 Colorimetric object

Claims (3)

A measurement unit having a measurement opening on which a color measurement object is disposed to face and visible light passes through;
A light emitting unit that irradiates light that does not include infrared light toward the measurement aperture;
A light receiving unit that receives light from the measurement aperture and obtains an electrical signal by photoelectric conversion;
A first infrared light cut portion disposed on the optical path from the measurement aperture to the light receiving portion and suppressing the passage of infrared light,
The light emitting unit is
A light source emitting light including infrared light, and a second infrared light cutting unit disposed on an optical path from the light source to the measurement aperture and suppressing passage of the infrared light ;
On the optical path from the light emitting unit to the light receiving unit, it has a filter that approximates the spectral response in the wavelength range of visible light to the weight coefficient,
The light receiving unit includes a first light receiving unit, a second light receiving unit, and a third light receiving unit,
The filter includes a first filter including, on an optical path from the measurement aperture to the first light receiver, a film that makes the spectral responsivity in the visible light wavelength range approximate to a weight coefficient x (λ);
The filter includes a second filter including, on an optical path from the measurement aperture to the second light receiver, a film that makes the spectral responsivity in the visible light wavelength range approximate to a weight coefficient y (λ);
Direct reading of stimulus value including the third filter including a film which makes the spectral responsivity of the visible light wavelength range approximate to the weight coefficient z (λ) on the optical path from the measurement aperture to the third light receiver Type colorimeter. The colorimeter according to claim 1, wherein
A colorimeter, wherein each of the first infrared cut portion and the second infrared cut portion includes an interference film. The colorimeter according to claim 1 or 2 , wherein
A colorimeter wherein the filter comprises an interference film.

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