JP2016211970A - Optical measurement device and optical measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical measurement technology that can obtain a plane intensity distribution of ultraviolet light.SOLUTION: An optical measurement device 10 comprises a wavelength conversion plate 20 that includes a wavelength conversion material converts ultraviolet light 61 into visible light 62, and has a first principal plane 21, and a second principal plane 22 provided on a side opposite the first principal plane 21 to convert the ultraviolet light 61 to be incident upon the first principal plane 21 into the visible light 62 and causing the visible light to be emitted. The optical measurement device 10 may include: a transparent substrate 24 that transmits the ultraviolet light 61; and a wavelength conversion layer 26 that includes the wavelength conversion material to be provided on the transparent substrate 24. The first principal plane 21, transparent substrate 24, wavelength conversion layer 26 and second principal plane 22 may be sequentially arranged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light measurement device and a light measurement method, and more particularly to measurement of ultraviolet light.

  Ultraviolet light is widely used in the fields of resin curing, sterilization or sterilization treatment in the medical and food fields. In order to appropriately obtain the sterilization effect or sterilization effect by ultraviolet light, it is necessary to irradiate the object to be treated with a predetermined intensity. As a method of measuring the intensity of ultraviolet light, a method of directly detecting ultraviolet light with a light receiving element such as a silicon photodetector, or a method of converting ultraviolet light into visible light using a phosphor and converting the intensity of visible light into ultraviolet light. There is a method of indirectly detecting the intensity (see, for example, Patent Document 1).

International Publication No. 00/11440

  An ultraviolet light emitting device in which a plurality of ultraviolet light sources are arranged in an array may be used so that sterilization or sterilization effect by ultraviolet light can be obtained in a wide area. In order to evaluate the characteristics of such a light emitting device, it is desirable to be able to measure the surface intensity distribution of ultraviolet light.

  The present invention has been made in view of such problems, and one of exemplary purposes thereof is to provide a light measurement technique capable of obtaining a surface intensity distribution of ultraviolet light.

  An optical measurement device according to an aspect of the present invention includes a wavelength conversion material that converts ultraviolet light into visible light, and is provided on a side opposite to the first main surface and the first main surface, and is incident on the first main surface. A wavelength conversion plate having a second main surface that converts light into visible light and emits the light.

  According to this aspect, the ultraviolet light incident on the first main surface of the wavelength conversion plate is converted into visible light, and the visible light having a surface intensity distribution corresponding to the surface intensity distribution of the ultraviolet light incident on the first main surface is the first. 2 is emitted from the main surface. For this reason, the intensity distribution of ultraviolet light can be visualized as the surface intensity distribution of visible light on the second main surface.

  The wavelength conversion plate has a transparent substrate that transmits ultraviolet light and a wavelength conversion layer that includes a wavelength conversion material provided on the transparent substrate, and the first main surface, the transparent substrate, the wavelength conversion layer, and the second main surface are You may arrange in order.

  An image sensor that measures the intensity distribution of visible light emitted from the second main surface, and a signal process that generates data indicating the surface intensity distribution of visible light emitted from the second main surface using a signal from the image sensor And a section.

  The wavelength conversion plate may be arranged to face a plurality of ultraviolet light sources arranged in an array, and the signal processing unit may output a feedback signal for controlling the light emission intensity of the plurality of ultraviolet light sources.

  The first main surface and the second main surface of the wavelength conversion plate may be configured by curved surfaces.

  The wavelength conversion material may convert ultraviolet light having a wavelength of 300 nm or less into visible light.

  Another aspect of the present invention is a light measurement method. This method includes a wavelength conversion material that converts ultraviolet light into visible light, is provided on the opposite side of the first main surface and the first main surface, and converts ultraviolet light incident on the first main surface into visible light. A wavelength conversion plate having a second main surface to be emitted and disposed so that the first main surface faces a plurality of ultraviolet light sources arranged in an array, and visible light emitted from the second main surface Observing light.

  According to the light measurement device and the light measurement method of the present invention, the surface intensity distribution of ultraviolet light can be easily obtained.

It is a figure which shows roughly the structure of the optical measurement apparatus which concerns on embodiment. It is a front view which shows the structure of a light-emitting device roughly. It is a figure which shows schematically the structure of the optical measurement apparatus which concerns on a modification.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

  FIG. 1 is a diagram schematically showing a configuration of a light measurement apparatus 10 according to an embodiment. The light measurement device 10 is a device that measures the intensity of ultraviolet light output from the light emitting device 50 and is a device that visualizes the surface intensity distribution of the ultraviolet light output from the light emitting device 50.

  The light emitting device 50 includes a plurality of ultraviolet light sources 52, a main body portion 54, and a driving portion 56.

  The ultraviolet light source 52 is an ultraviolet lamp or an LED (Light Emitting Diode) that emits ultraviolet light. In the present embodiment, a UV-LED is used as the ultraviolet light source 52, and an LED whose central wavelength or peak wavelength is included in the ultraviolet region of about 200 nm to 300 nm is used. When the light-emitting device 50 is used for sterilization, it is preferable to use a device that emits ultraviolet light near 260 nm, which is a wavelength with high sterilization efficiency. As such an ultraviolet light LED, for example, one using aluminum gallium nitride (AlGaN) is known. In addition, when using for other uses, such as resin hardening, what is necessary is just to select the light source which emits the ultraviolet light of the wavelength suitable for a use.

  The plurality of ultraviolet light sources 52 are arranged in an array on the surface 55 of the main body 54 as shown in FIG. For example, the ultraviolet light source 52 is arranged in a tetragonal lattice shape or a hexagonal lattice shape. Thereby, the plurality of ultraviolet light sources 52 radiate ultraviolet light in a planar shape toward the irradiated object facing the surface 55. Therefore, it can be said that the light emitting device 50 is an ultraviolet light surface emitting device.

  The main body 54 fixes a plurality of ultraviolet light sources 52. The main body 54 includes, for example, a mounting board to which the ultraviolet light source 52 is directly attached and a heat sink that is thermally connected to the mounting board. The main body 54 may have a cooling mechanism for cooling the heat sink with air or water. The main body 54 may have a reflection mechanism that reflects the ultraviolet light emitted from the ultraviolet light source 52 and directs it toward the irradiated object. Such a reflection mechanism desirably has an aluminum (Al) reflecting surface having a high reflectivity of ultraviolet light.

  The drive unit 56 generates a drive current for causing the plurality of ultraviolet light sources 52 to emit light, and supplies the drive current to the ultraviolet light source 52. For example, the drive unit 56 supplies the ultraviolet light source 52 with a constant current that provides a predetermined light emission intensity. The drive unit 56 is configured to be able to supply drive currents having different values to the respective ultraviolet light sources 52 so that the light emission intensities of the plurality of ultraviolet light sources 52 attached to the main body unit 54 can be individually adjusted. Moreover, the drive part 56 controls the drive current of each ultraviolet light source 52 based on the feedback signal from the signal processing part 40 mentioned later.

  The light measurement device 10 includes a wavelength conversion plate 20, an imaging unit 30, and a signal processing unit 40.

  The wavelength conversion plate 20 has a first main surface 21 on which ultraviolet light 61 is incident, a transparent substrate 24, a wavelength conversion layer 26, and a second main surface 22 from which visible light 62 is emitted. The 1st main surface 21, the transparent substrate 24, the wavelength conversion layer 26, and the 2nd main surface 22 are arrange | positioned in this order. The wavelength conversion plate 20 is disposed so as to face the plurality of ultraviolet light sources 52, and is provided, for example, so as to cover the entire surface 55 of the light emitting device 50.

The transparent substrate 24 is a plate-like member made of a material that transmits ultraviolet light, and is made of quartz (SiO ₂ ), sapphire (Al ₂ O ₃ ), or the like. The transparent substrate 24 may be made of a resin material having a high ultraviolet light transmittance. When the transparent substrate 24 is a resin material, a fluorine resin such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) or PTFE (polytetrafluoroethylene), a transparent silicone resin, or the like may be used.

  The wavelength conversion layer 26 is a layer containing a wavelength conversion material that converts ultraviolet light into visible light. In the present embodiment, a phosphor that emits visible light fluorescence using ultraviolet light as excitation light is used as the wavelength conversion material. The phosphor desirably has high excitation efficiency with respect to ultraviolet light having a wavelength of 200 nm to 300 nm. As such a phosphor, for example, a phosphor (for example, blue phosphor: D1230, green phosphor: D1164, red phosphor: D1120) manufactured by Nemoto Lumi Materials, Inc. may be used.

  The wavelength conversion layer 26 can be formed by applying a mixture of the above-described phosphor to a binder mainly composed of silicon (Si) or the like on the surface of the transparent substrate 24 and baking it. The wavelength conversion layer 26 is desirably formed so that the concentration of the phosphor is uniform on the second main surface 22 so that visible light 62 proportional to the intensity of the incident ultraviolet light 61 can be emitted. The surface of the transparent substrate 24 may be provided with a fine concavo-convex structure for improving the adhesion with the binder.

  The imaging unit 30 includes a wavelength filter 32, an imaging lens 34, and an imaging element 36. That is, the imaging unit 30 is, for example, a camera for acquiring a visible light image of the second main surface 22.

  The wavelength filter 32 is a low-pass filter that transmits visible light and blocks ultraviolet light. Providing the wavelength filter 32 prevents the resin material used for sealing the imaging element 36 and the imaging unit 30 from being irradiated with ultraviolet light and being deteriorated. The wavelength filter 32 may be a band-pass filter that selectively passes the wavelength of visible light output from the wavelength conversion layer 26.

  The imaging lens 34 images the visible light emitted from the wavelength conversion plate 20 on the imaging element 36. The imaging lens 34 may be configured by a single lens or a lens group including a plurality of lenses. The imaging lens 34 may have a zoom function so that the magnification of an image formed on the imaging element 36 can be changed.

  The image sensor 36 is a photoelectric conversion element that generates an electrical signal corresponding to the intensity of incident light. In the present embodiment, the image sensor 36 is a two-dimensional image sensor capable of generating an image signal corresponding to an image formed by the imaging lens 34, and is, for example, a CCD image sensor or a CMOS image sensor. The image sensor 36 may be configured to be able to generate a grayscale image signal, or may be configured to be able to generate a color image signal. The image signal generated by the image sensor 36 is sent to the signal processing unit 40.

  The signal processing unit 40 generates data indicating the surface intensity distribution of the visible light 62 emitted from the second main surface 22 using the signal from the image sensor 36. The signal processing unit 40 generates grayscale image data in which the intensity of light intensity corresponds to the luminance value of each pixel as the surface intensity distribution data on the second main surface 22. When the image sensor 36 can measure a color image, the signal processing unit 40 may generate color image data corresponding to the case where the second main surface 22 is viewed. The signal processing unit 40 may output the generated image data to a display (not shown) or the like for visualization, or may output the image data to an external computer or the like for further data processing.

  The signal processing unit 40 analyzes the generated image data and controls the light emission intensity of the plurality of ultraviolet light sources 52 so that the surface intensity distribution of the visible light emitted from the second main surface 22 has a desired value. The feedback signal is output to the drive unit 56. For example, the signal processing unit 40 outputs a lighting instruction signal for individually controlling lighting and extinguishing of the ultraviolet light source 52 to the driving unit 56, and determines the position of the lit ultraviolet light source 52 in the image data. . The signal processing unit 40 calculates the intensity based on the contribution of each of the plurality of ultraviolet light sources 52 by determining the position of the ultraviolet light source 52, and outputs a feedback signal so that these intensities are uniform. The signal processing unit 40 may output a feedback signal so that the intensity distribution of visible light emitted from the second main surface 22 becomes a desired distribution that is not uniform.

  Next, the optical measurement method according to the present embodiment will be described. First, the wavelength conversion plate 20 is prepared, and the wavelength conversion plate 20 is arranged so that the first main surface 21 of the wavelength conversion plate 20 faces a plurality of ultraviolet light sources 52 arranged in an array. Subsequently, the visible light 62 emitted from the second main surface 22 of the wavelength conversion plate 20 is observed. The visible light 62 emitted from the second main surface 22 may be confirmed by visual observation, or may be measured using an imaging element included in the imaging unit 30 or the like.

  The light measuring device 10 may be temporarily disposed on the front surface of the light emitting device 50 when the measurement of the ultraviolet light intensity of the light emitting device 50 is required, or may be always disposed on the front surface of the light emitting device 50 to the light emitting device 50. A feedback signal may be provided. In the latter case, the light measurement device 10 may be incorporated in a device or the like in which the light emitting device 50 is provided. In addition, the light measurement device 10 may measure the surface intensity distribution of the ultraviolet light output from the light emitting device 50 in an arrangement where the irradiation target of ultraviolet light is located between the light emitting device 50 and the wavelength conversion plate 20.

  According to the present embodiment, since the intensity distribution of the ultraviolet light 61 from the light emitting device 50 is measured via the visible light 62, the surface intensity distribution of the ultraviolet light is obtained using the visible light imaging element or camera. Can do. In general, an image sensor for ultraviolet light is more expensive than a general-purpose image sensor for visible light. In addition, a light receiving element for ultraviolet light using a silicon photodetector or the like may have a semiconductor element portion sealed with a resin material or the like. As a result, the characteristics of the light receiving element deteriorate. If it does so, the intensity | strength of the ultraviolet light measured will not be stabilized, and the reliability as a measuring apparatus will fall. In addition, it is necessary to frequently replace the light receiving element, and the maintenance cost increases.

  On the other hand, according to the present embodiment, since the ultraviolet light 61 is converted into the visible light 62 by the wavelength conversion plate 20 and measured, the influence of deterioration of the image sensor due to the ultraviolet light can be reduced. Thereby, the reliability as a measuring apparatus can be improved. Moreover, the cost of the optical measurement device 10 can be reduced by using an imaging element for visible light. Further, by converting the ultraviolet light 61 into the visible light 62, it is possible to improve safety when the surface intensity distribution of the light emitting device 50 is visually confirmed.

  Further, according to the present embodiment, the surface intensity distribution of the ultraviolet light 61 incident on the wavelength conversion plate 20 is visible with high accuracy by providing the wavelength conversion layer 26 on the second main surface 22 to be observed of the visible light 62. The light 62 can be converted into a surface intensity distribution. If a wavelength conversion material is formed by mixing a wavelength conversion material with a thick base material such as the transparent substrate 24, conversion from ultraviolet light to visible light occurs at different positions in the thickness direction where the ultraviolet light travels. At this time, since the ultraviolet light output from the light emitting device 50 is not necessarily parallel light, the surface intensity distribution may be different depending on the position in the traveling direction of the ultraviolet light. As a result, visible light having a surface intensity distribution having a different shape is superimposed in the thickness direction, and visible light having a surface intensity distribution that is out of focus is generated. Then, the deviation between the surface intensity distribution of the ultraviolet light to be measured and the surface intensity distribution of the visible light actually observed becomes large.

  On the other hand, according to the present embodiment, since the wavelength conversion layer 26 having a relatively small thickness is provided on the second main surface 22, the surface intensity distribution of the ultraviolet light 61 incident on the wavelength conversion layer 26 and the wavelength conversion layer 26. The deviation from the surface intensity distribution of the visible light 62 emitted from the light can be reduced. Thereby, the surface intensity distribution of the ultraviolet light output from the light emitting device 50 can be accurately measured. Further, by changing the position of the wavelength conversion plate 20 in the traveling direction of the ultraviolet light, it is possible to easily measure the surface intensity distribution of the ultraviolet light on different observation surfaces.

  FIG. 3 is a diagram schematically showing the configuration of the light measurement apparatus 110 according to the modification. This modification is different from the above-described embodiment in that the light emitting device 150 in which a plurality of ultraviolet light sources 52 are provided on the curved surface 155 is a measurement target. In addition, the wavelength conversion plate 120 of the optical measurement device 110 has a first main surface 121 and a second main surface 122 that are configured by curved surfaces corresponding to the curved main body portion 154. Hereinafter, this modified example will be described focusing on differences from the above-described embodiment.

  The light emitting device 150 includes a main body 154 having a curved surface 155. The plurality of ultraviolet light sources 52 are attached to the curved surface 155. The curved surface 155 in this modification is formed to be a concave surface. Therefore, the light emitting device 150 can output ultraviolet light so as to be condensed toward the irradiation object.

  The wavelength conversion plate 120 has a first main surface 121, a transparent substrate 124, a wavelength conversion layer 126, and a second main surface 122 that are arranged in order. The first main surface 121 is a convex surface that faces the curved surface 155 of the light emitting device 150 and has a shape corresponding to the curved surface 155 that is a concave surface. The second main surface 122 is provided such that the distance from the first main surface 121 is constant, and is configured as a concave surface having a shape corresponding to the first main surface 121. Similarly, the transparent substrate 124 and the wavelength conversion layer 126 have a curved shape.

  The visible light 62 emitted from the second main surface 122 is measured by the imaging unit 30. The image signal measured by the imaging unit 30 is sent to the signal processing unit 40 to generate and analyze image data.

  According to this modification, the observation surface on which the surface intensity distribution of the ultraviolet light is to be measured can be curved by using the wavelength conversion plate 120 in which the first major surface 121 and the second major surface 122 are curved surfaces. . Thereby, about the light-emitting device 150 which outputs the ultraviolet light which condenses toward an irradiation object, the surface intensity distribution of ultraviolet light can be measured suitably.

  In a further modification, an optical measurement device in which the first main surface of the wavelength conversion plate is a concave surface and the second main surface is a convex surface may be used. Further, a wavelength conversion plate having a curved surface that is unevenly curved may be used in accordance with the shape of the light emitting device to be measured. Further, for the light emitting device 50 in which a plurality of ultraviolet light sources 52 are arranged on a plane as in the above-described embodiment, a wavelength conversion plate in which the first main surface and the second main surface are curved surfaces may be used. . Conversely, for the light emitting device 150 according to the modification, the wavelength conversion plate 20 in which the first main surface 21 and the second main surface 22 are flat surfaces as in the above-described embodiment may be used. That is, a wavelength conversion plate having an appropriate shape may be used according to the shape of the observation surface to be measured.

  In the above, this invention was demonstrated based on the Example. It is understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, and various modifications are possible, and such modifications are within the scope of the present invention. It is a place.

  In the embodiment and the modification described above, the surface intensity distribution of visible light is measured using the imaging unit 30 capable of measuring two-dimensional light intensity. In a further modification, the light intensity distribution may be measured using a plurality of light receiving elements arranged in a line in a line or a plurality of light receiving elements arranged in an array. Alternatively, the surface intensity distribution may be measured by moving the light receiving element in a direction intersecting the traveling direction of visible light emitted from the second main surface 22 and moving the light receiving element so as to scan the measurement target. .

  In a further modification, a plurality of types of phosphors may be included in the wavelength conversion layer. Specifically, a plurality of types of phosphors having different excitation wavelengths and fluorescence wavelengths are included in the wavelength conversion layer, and the intensity for each wavelength of ultraviolet light output from the light emitting device is determined from the intensity for each wavelength of visible light to be measured. It may be calculated.

  In a further modification, the wavelength conversion layer may be provided not on the second main surface but on the first main surface on which ultraviolet light is incident. In this case, a material having a low ultraviolet light transmittance and a high visible light transmittance, such as borosilicate glass, may be used as the transparent substrate of the wavelength conversion plate.

  DESCRIPTION OF SYMBOLS 10 ... Light measuring device, 20 ... Wavelength conversion board, 21 ... 1st main surface, 22 ... 2nd main surface, 24 ... Transparent substrate, 26 ... Wavelength conversion layer, 36 ... Image sensor, 40 ... Signal processing part, 52 ... Ultraviolet light source, 61 ... ultraviolet light, 62 ... visible light.

Claims (7)

  It includes a wavelength conversion material that converts ultraviolet light into visible light, is provided on the first main surface and on the opposite side of the first main surface, and converts ultraviolet light incident on the first main surface into visible light, which is emitted. An optical measurement device comprising a wavelength conversion plate having a second main surface to be made.   The wavelength conversion plate includes a transparent substrate that transmits ultraviolet light, and a wavelength conversion layer including the wavelength conversion material provided on the transparent substrate, and the first main surface, the transparent substrate, and the wavelength conversion layer. The light measuring device according to claim 1, wherein the second main surface is arranged in order. An image sensor for measuring an intensity distribution of visible light emitted from the second main surface;
The signal processing part which produces | generates the data which show the surface intensity distribution of the visible light radiate | emitted from the said 2nd main surface using the signal from the said image pick-up element is further provided. Light measuring device. The wavelength conversion plate is arranged to face a plurality of ultraviolet light sources arranged in an array,
The optical measurement apparatus according to claim 3, wherein the signal processing unit outputs a feedback signal for controlling emission intensity of the plurality of ultraviolet light sources.   5. The optical measurement device according to claim 1, wherein the first main surface and the second main surface of the wavelength conversion plate are configured by curved surfaces. 6.   The light measuring device according to any one of claims 1 to 5, wherein the wavelength conversion material converts ultraviolet light having a wavelength of 300 nm or less into visible light. It includes a wavelength conversion material that converts ultraviolet light into visible light, is provided on the first main surface and on the opposite side of the first main surface, and converts ultraviolet light incident on the first main surface into visible light, which is emitted. A wavelength conversion plate having a second main surface to be disposed such that the first main surface faces a plurality of ultraviolet light sources arranged in an array;
Observing visible light emitted from the second main surface. A light measurement method comprising:

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