JP5774551B2 - Photometric device - Google Patents

Description

  The present invention relates to a photometric device that is used in a photometer, a colorimeter, or the like that collects light emitted from a light source on the surface of an object to be measured and detects reflected light reflected from the surface of the object to be measured by a light receiving unit.

  A light source consisting of LEDs is attached to the circuit board, and the light emitted from the light source is condensed below the opening of the main body cover with a conical surface having a reflecting surface formed on the main body cover, and applied to the surface of the object to be measured. 2. Description of the Related Art A spectrophotometer that guides reflected light reflected from the surface of an object to be measured to a spectrum sensor through a lens system and measures the spectral reflectance of the surface of the object to be measured by the spectrum sensor has been conventionally known (see, for example, Patent Document 1). ).

Special table 2010-523984 gazette

In the configuration in which the light emitted from the light source is condensed on the surface of the object to be measured by the conical surface of the spectrophotometer main body cover, the conical surface for condensing the main body cover needs to be processed into a mirror surface. For this reason, there is a limit to shortening the focal length by the inclined conical surface of the main body cover, and there is a problem that the main body cover becomes large because the portion affected by the size of the LED is large.
A main object of the present invention is to provide a photometric device used for a photometer, a colorimeter, or the like that collects light emitted from a light source on the surface of the object to be measured and detects reflected light reflected from the surface of the object to be measured by a light receiving unit. The above-mentioned problem is solved by condensing the light emitted from the light source with a lens and reducing the distance from the light emitting unit to the measurement object so that the focal length can be shortened.
Another object of the present invention is to provide a photometric device used in a spectrophotometer or the like that can easily detect reflected light even when the measurement surface of the object to be measured is a narrow place. is there.

In order to achieve the above object, the present invention is a photometric device that collects light emitted from a light source and applies the light to a surface of an object to be measured and reflects the reflected light to a photosensor to detect the reflected light. A lens for condensing the light emitted from the light source is disposed on the optical path of the light emitted from the light source, a cavity through which the reflected light is transmitted is provided in the lens, and the reflection reflected from the surface of the object to be measured The light is allowed to reach the optical sensor through the cavity.
Further, the present invention is characterized in that an electronic circuit for converting the signal detected by the optical sensor into data representing the color of the surface of the object to be measured and outputting it is provided to function as a colorimeter.
Further, the present invention is characterized in that an electronic circuit for measuring the spectral reflectance of the surface of the object to be measured is provided according to a signal detected by the optical sensor and functions as a spectrophotometer.
In the present invention, a light guide for light irradiation optical path is disposed between the light source and the lens, and a light guide for light reflection optical path is disposed between the cavity of the lens and the optical sensor, Light that has passed through the light guide for the light irradiation optical path is irradiated onto the lens, and the reflected light of the light that has passed through the lens and hit the object to be measured passes through the cavity of the lens and is guided to the light reflection optical path. It is characterized by entering into a light body.
Further, the present invention is characterized in that a plurality of the light sources are provided, each of the light sources is arranged along the circumference immediately above the lens, and the light emitted from each light source is condensed by the lens. To do.
In the invention, it is preferable that each light source has a different wavelength band.
Further, the present invention is characterized in that a plurality of the light sources are provided, each light source has a different wavelength band, and the photosensor comprises a plurality of photodetection circuits.
In the present invention, a plurality of the light sources are provided, and the light sources are arranged at equal intervals along the circumference immediately above the lens so that light emitted from the light sources is collected by the lens. It is characterized by.
Further, the invention is characterized in that the light guide for the light irradiation optical path and the light guide for the light reflection optical path are made of optical fibers.
In the present invention, the light source, the sensor, and the lens are incorporated in a main body cover, and light passing through the lens is irradiated from the opening of the main body cover to the object to be measured. The light reflected from the light enters the main body cover.
In the present invention, the light source and the sensor are built in a main body cover, the lens with the cavity is disposed in a tip cover separate from the main body cover, and the main body cover and the tip cover are used for the light irradiation optical path. A light guide and a light-reflecting light path light guide connected to each other, light passing through the light-irradiating light path light guide is irradiated to the lens, and reflected light passing through the lens cavity is reflected by the light-reflecting light path. In this case, the light sensor is guided to the optical sensor through a light guide body.
In the invention, it is preferable that the lens is a Fresnel lens.

In the present invention, since the light emitted from the light source is collected by the lens having the cavity, the focal length of the light can be shortened, and the distance from the light source of the apparatus to the measurement object can be reduced.
In addition, since the reflected light passes through the lens cavity, attenuation of light by the lens can be prevented, and light can be directly received by the sensor. In addition, if the light source guides the light from the light source to the lens, it can be configured with a diameter corresponding to the diameter of the aggregate of the light guides compared to the diameter of the LED or light receiving unit provided in the device body. The diameter at the part can be reduced, and by using a small diameter perforated lens, the diameter of the tip can be reduced and the distance from the light guide to the object to be measured can be reduced. Therefore, it is possible to make a photometric device that can reduce the lens diameter and reduce the diameter of the lens and detect reflected light in a narrow place.

It is a section explanatory view of the photometry device concerning the present invention. It is a top view of a lens. It is bottom face explanatory drawing of the circuit board of a photometry apparatus. It is a section explanatory view showing other embodiments of the present invention.

Embodiments in which the photometric device of the present invention is configured as a spectrophotometer will be described in detail below with reference to the accompanying drawings.
FIG. 1 is an explanatory diagram of the internal structure of a spectrophotometer 2 in which the photometric device according to the present invention is used for use in a colorimeter.
A plurality of light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h made of light emitting diodes (LEDs) are provided on a circuit board 4 on which circuits such as a CPU, a memory, an input / output interface, a driver, and a receiving circuit are formed. As shown in FIG. 3, they are arranged at equal intervals on the circumference.

A plurality of light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h are arranged inside the cover 8 so as to protrude downward toward the object to be measured 10, and each light source 6a, 6b, 6c, 6d, A condensing lens 12 having a cavity 12a formed in the center is disposed below 6e, 6f, 6g, and 6h. The lower ends of the light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h are in contact with the lens 12 or opposed to each other with an appropriate distance. The lower ends of the light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h are arranged at equal intervals on a concentric circle centered on the cavity 12a of the lens 12. The lens 12 is held on the outer periphery of a cylindrical light shielding partition 14 attached to the circuit board 4. In this embodiment, the lens 12 is a Fresnel lens. Note that either surface of the Fresnel lens may be installed on the light source side as required.

Inside the light shielding partition 14 for shielding light from the light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h, the light is reflected from the surface of the object to be measured 10 and enters the chamber of the cover 8. A geometry converter 18 with a filter 16 is arranged that constitutes an optical path geometry converter designed to direct and focus the light. In addition, a detection unit 20 including an optical sensor 22, an etalon 24, and a face plate 26 is disposed above the geometry converter 18 inside the light shielding partition 14, and serves as a reception circuit of the circuit unit of the circuit board 4. Electrically connected. The detection unit 20 is attached to the circuit board 4, and the geometry converter 18 is held by the light shielding partition 14. The geometry converter 18 and the detection unit 20 are configured not to be affected by the light from the light source by the light shielding partition 14.

The light that has passed through the geometry converter 18 becomes a thin line that matches the surface area of the detection unit 20. The detection unit 20 serves as a “digital prism” that converts multicolor or “white” light into the spectrum that composes it, and the spectrum has a visible spectrum (VIS) with a wavelength between 350 nm and 750 nm. Included are white light, near infrared (NIR) light at wavelengths between 750 nm and 1500 nm, far infrared light (IR) above 1500 nm wavelengths, and ultraviolet (UV) light below 350 nm wavelengths. The following three major sub-components are incorporated in the assembly constituting the detection unit 20.

One is a photosensor 22 consisting of a photo-detector array of photosensitive photodiodes that coincides with the wavelength region of interest, with a linear array or row of photo-detector sites forming the major axis. The row of light detectors is composed of a plurality of photodetector sites arranged in a substantially rectangular group having a short axis. The photosensor 22 may comprise a sensor comprising a phototransistor or other similar photodetection circuit in addition to a photodiode. Second, the thickness of the synthetic interference coating layer was applied from edge to edge so that a wedge-like shape was formed on a submicron scale along the long axis of the photodetector array. The etalon 24 is formed of a number of bandpass filter coating layers.

In the etalon 24, the center wavelength of each passband is a function of the coating thickness, so that the peak wavelength transmitted through a given point on the filter varies approximately linearly in the direction of the filter coating wedge, i.e., the sensor's long axis. . The third is an array of optically clear plastic or glass optical fiber elements with a diameter of 5 microns to 100 microns, the same center-to-center spacing, and a low numerical aperture. A similar monolithic plate of light-absorbing material, such as an EMA-type material, with a diameter of 5 to 100 microns, with a center-to-center spacing A collimating faceplate 26 comprising a plate in which an array of holes or capillaries that are the same is etched, light penetrated or otherwise cut into the light absorbing plate.

In the collimating faceplate 26, whether it is an optical fiber or capillary array design, the purpose of the faceplate 26 is to collimate the light incident on the interference filter coating and to have an incident angle greater than 20 degrees relative to the coated surface. A series of cones that reject light and have a half-width of 20 degrees or less overlap so that the overlap area is sufficient to provide a generally uniform illumination level over the entire area of the coating layer that is superimposed on the array of photodetectors. It is to appear in the form.

  In the configuration described above, the light from the light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h passes through the lens 12, and is individually collected in the direction of arrow A, and exits the opening of the cover 8. It hits the surface of the DUT 10. The reflected light that hits the surface of the object to be measured 10 and is generated in the direction of the arrow B passes through the geomerie converter 18 and enters the detection unit 20, and the reflected light is detected by the optical sensor 22. Ten surface spectral reflectances are detected. The detection signal of the optical sensor 22 is converted into color measurement numerical data that quantitatively represents the color of the reflected light by a color measurement circuit provided on the circuit board 4, and the spectrophotometer of this embodiment is used as a colorimeter. .

Next, another embodiment of the present invention will be described in detail with reference to FIG.
A plurality of light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h made of light emitting diodes are mounted on the circuit board 4 so as to be arranged at equal intervals on the circumference as shown in FIG. A plurality of light sources 6 a, 6 b, 6 c, 6 d, 6 e, 6 f, 6 g, 6 h are arranged in a chamber in the cover 28 so as to protrude from the lower surface of the circuit board 4 with the irradiation direction facing downward. Below the light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h, there are arranged flexible and flexible elongated light guides 30 for light irradiation optical paths. , And is guided to the outside through a hole 32 formed in the bottom wall of the cover 28.

Each light guide 30 for light irradiation optical path is held by a cover 28, and one end of each light guide 30 is in contact with the corresponding light source 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, respectively. Opposed to each other with appropriate distance. The circuit board 4 is provided with a cylindrical light shielding partition 14 projecting downward on the lower surface thereof, and the light shielding partition 14 is located on the optical path of the light reflected from the object 10 to be measured. A geometry converter 18 including the filter 16 and a detection unit 20 are arranged, and the detection unit 20 is electrically connected to a corresponding reception circuit provided on the circuit board 4.

The detection unit 20 is attached to the circuit board 4, and the geometry converter 18 is held by the light shielding partition 14. One end of a light-reflecting optical path light guide 34 is disposed below the geometry converter 18, and the light guide 34 is held by the cover 28 and led to the outside through a hole 32 formed in the bottom wall of the cover 28. ing. The light guide 30 for the light irradiation optical path and the light guide 34 for the light reflection optical path guided to the outside from the cover 28 by a predetermined length are opened at the lower ends through holes formed in the upper wall of the tip cover 36. The light guides 30 and 34 are guided to the inside of the tip cover 36 and held by the tip cover 36. The light guides 30 and 34 are illustrated separately for convenience of explanation in the figure, but in an actual product, a plurality of light guides are collected and covered in the form of a cord and can be freely bent. It is in a state.

A condensing lens 38 having a cavity 38 a formed in the center is disposed inside the tip cover 36, and the lens 38 is held by the tip cover 36. In this embodiment, the lens 38 is a Fresnel lens. The planar shape of the lens 38 is the same as the planar shape of the lens 12 shown in FIG. The tips of the light guide 30 for the light irradiation optical path are arranged opposite to each other at equal intervals on a concentric circle centering on the cavity 38 a of the lens 38, and the tip of the light guide 34 for the light reflecting optical path is a cavity of the lens 38. It is arranged immediately above the portion 38a. The tip of the light guide 30 for the light irradiation optical path is in contact with the lens 12. Note that they may be arranged facing each other with an appropriate distance.

  In the above-described configuration, light from the light sources 6a, 6b, 6c, 6d, 6e, 6f, 6g, and 6h passes through the light guide 30 and the lens 38, and is condensed in the direction of the arrow A, and the tip cover 36 The lower opening portion of the object is exposed to the surface of the object 10 to be measured. The reflected light that hits the surface of the DUT 10 and is generated in the direction of arrow B passes through the light guide 34 and is guided under the geometry converter 18 and exits from the upper end of the light guide 34. The reflected light that has exited the light guide 34 passes through the geometry converter 18, is converged there, enters the detection unit 20, and the spectral reflectance of the surface of the object to be measured is detected. Although not shown in the figure, a partition may be provided at the boundary between the light guides 30 and 34 so that only the reflected light enters the light guide 34.

  In the present embodiment, a lens 38 is disposed in a tip cover 36 that is separate from the main body side cover 28 of the spectrophotometer 2, and the light sources 6 a, 6 b, 6 c, 6 d, 6 e, 6 f, 6 g, 6 h are disposed on the lens 38. Is guided through the light guide 30, the light passing through the lens 38 is applied to the device under test 10, and the reflected light is guided into the main body side cover 28 through the light guide 34. Compared to the diameter of the LED and detection unit (light receiving unit) provided on the main body, it can be configured with a size corresponding to the diameter of the assembly of light guides, so the diameter at the tip of the device can be reduced, and there is a small diameter By using a lens with a hole, it is possible to reduce the diameter of the tip and the distance from the light guide to the object to be measured. It becomes. Therefore, the miniaturized tip cover 36 can be moved to an arbitrary narrow place, the reflected light at a special narrow place can be detected, and colorimetry can be performed.

In the above embodiment, the light source includes a plurality of LEDs arranged in an array, and each LED is configured to be individually and adjustably energized in order to change the output intensity of the LED. Are energized individually and adjustable by a pulse width modulation signal.
Each LED also has a predetermined spectral bandwidth with a different center wavelength, and the spectral bandwidths of all LEDs produce white light when combined. This white light is used to illuminate the object to be measured for the purpose of color measurement. A spectrophotometer that uses various LEDs as a light source, the state of fluorescence in other materials such as printing media and colorants, by making at least one of the light source LEDs emit ultraviolet radiation. Can be used to inspect.
Also, a plurality of LEDs having different wavelength ranges are individually selected, and can be used for analysis according to the purpose of measurement if they are combined in different wavelength ranges.
The present invention is applied to a photometric device such as a photometer, an illuminometer, and a colorimeter that collects and irradiates light from a light source on the surface of an object to be measured, detects the reflected light, and measures it with an appropriate electronic circuit It can be used, and is not particularly limited to the spectrophotometer described as the embodiment.

2 spectrophotometer 4 circuit board 6a light source 6b light source 6c light source 6d light source 6e light source 6f light source 6g light source 6h light source 8 cover 10 object to be measured 12a cavity 14 light shielding partition 16 filter 18 geometry converter 20 detector 22 optical sensor 24 etalon 26 Face plate 28 Cover 30 Light guide 32 Hole 34 Light guide 36 Tip cover 38a Cavity 38 Lens

Claims (7)

A photometric device that collects light emitted from a light source, hits the surface of an object to be measured and reflects the reflected light to a light sensor, and detects the reflected light. A circuit board, a light source disposed in the body cover toward the object to be measured and attached to the circuit board, a condensing lens in which a cavity for passing reflected light is formed, and an optical sensor, A detection unit electrically connected to an electronic circuit of the circuit board, a geometry converter for directing and focusing reflected light passing through the cavity of the lens, and an inside of the body cover A cylindrical light-shielding partition, and the reflected light reflected from the surface of the object to be measured passes through the cavity of the lens and reaches the optical sensor through the geometry converter, and is influenced by the light source. Not to said Out section and placing the geometry converter to the light-shielding partition body, wherein the light source and arranged lightguide for light irradiation optical path between said focusing lens, wherein the cavity of the condensing lens geo A light guide for a light reflection optical path is disposed between the light source and the detection converter, the light source and the detection unit are incorporated in a main body cover, and the condensing lens with a cavity is provided at a tip cover separate from the main body cover. And connecting the main body cover and the tip cover with the light guide for the light irradiation optical path and the light guide for the light reflection optical path, and connecting the tip of the light guide for the light irradiation optical path on the tip cover side. The light guide for the light-reflecting optical path is arranged directly above the cavity of the light-collecting lens on the tip cover side. The light passing through is irradiated onto the condensing lens on the tip cover side, and the condensing lens Photometric device reflected light which has passed through the cavity of the lens is characterized in that so as to be guided to the optical sensor of the detection unit of the main body cover side through the light guide for the light reflection optical path. 2. The photometric device according to claim 1, wherein the light guide for the light irradiation optical path and the light guide for the light reflection optical path are made of optical fibers. The detection unit includes the optical sensor, an etalon formed of a number of bandpass filter coating layers, and a collimating faceplate that collimates light incident on the etalon and provides a uniform irradiation level to the etalon. The photometric device according to claim 1, which is configured. The photometric device according to claim 1, wherein a signal detected by the photosensor is converted into data representing a color of the surface of the object to be measured by an electronic circuit of the circuit board and functions as a colorimeter. . 2. The photometric device according to claim 1, wherein a signal detected by the optical sensor is converted into a spectral reflectance of the surface of the object to be measured by an electronic circuit of the circuit board, and functions as a spectrophotometer. The photometric device according to claim 1, wherein a plurality of the light sources are provided, and each of the light sources has a different wavelength band. 2. The photometric device according to claim 1, wherein a plurality of the light sources are provided, each light source has a different wavelength band, and the photosensor includes a plurality of photodetection circuits.

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