CN112424575B

CN112424575B - Photometry device

Info

Publication number: CN112424575B
Application number: CN201980047134.XA
Authority: CN
Inventors: 中谷通
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 2018-07-19
Filing date: 2019-04-15
Publication date: 2024-01-12
Anticipated expiration: 2039-04-15
Also published as: JPWO2020017118A1; JP7415923B2; KR20210021054A; KR102609046B1; CN112424575A; WO2020017118A1

Abstract

The photometry device (1) is provided with a light guide member (2) having a polygonal or polygonal pyramid shape on a light-incident-side end surface (2 a) and a light-emergent-side end surface (2 b), an objective optical system (3), and a light receiving unit (5). The objective optical system (3) forms an image of the Light Source (LS) to be measured on the light-incident side end surface (2 a) of the light guide member (2). The light receiving unit (5) receives light that has been incident on the light guide member (2) from the Light Source (LS) to be measured via the objective optical system (3) and has been emitted from the light-emitting-side end surface (2 a) of the light guide member (2). The light receiving section (5) has a plurality of sensors (51) having different characteristics, and is disposed immediately after the light emitting side end face (2 b) of the light guiding member (2), or is disposed with the relay optical system (4) interposed between the light emitting side end face (2 b) of the light guiding member (2) so that the light emitting side end face (2 b) of the light guiding member (2) is conjugate with the light receiving surface (5 a) of the light receiving section (5).

Description

Photometry device

Technical Field

The present invention relates to a photometry device for measuring characteristics of a light source to be measured, and more particularly, to a photometry device such as a color luminance meter for measuring luminance or chromaticity of light emitted from a light source to be measured.

Background

In a light measuring device such as a color luminance meter, measurement light is split into 3 paths and received by each sensor in order to measure color. As a mechanism for dividing measurement light into 3 paths, for example, patent document 1 proposes a light guide in which a plurality of optical fibers are bundled. The light guide is configured such that the incident side of the measurement light is collected into 1 fiber bundle and the emission side is divided into 3 fiber bundles. Light emitted from the end surfaces of the 3 fiber bundles is incident on the light receiving element through filters having characteristics of transmitting red (R), green (G), and blue (B) light.

The plurality of optical fibers are bundled so that the imaging positional relationship of the imaging light beam formed by imaging the end face of the incident side of the measurement light is pseudo-random. Accordingly, the image forming light fluxes emitted from the end faces of the 3 fiber bundles on the light emitting side and incident to the respective light receiving elements are pseudo-randomly mixed, and thus the light quantity unevenness of the image forming light fluxes is reduced.

Prior art literature

Patent literature

Patent document 1: JP 2010-2255A (see claims 1, 4, paragraphs [0001], [0023] to [0028], FIGS. 1 to 3, etc.)

Disclosure of Invention

Problems to be solved by the invention

However, the color measurement by the photometry device is performed by bringing a surface to be measured of an object to be measured (a light source to be measured) into contact with the photometry device, or by receiving light emitted from a predetermined area of the surface to be measured at a predetermined angular range via the photometry device, without bringing the surface to be measured into contact with the photometry device. In this case, if there is an unevenness (positional unevenness, angular unevenness) in the light emission intensity (light emission luminance) of the surface to be measured due to the light emission position and the light emission angle, the photometry device side is also affected by this. If the position unevenness and the angle unevenness of the measurement sensitivity become large on the side of the photometry device due to the influence described above, the difference in measurement value (measurement error) becomes large due to the difference in the measured position and the measured angle. The position unevenness of the measurement sensitivity means that the measurement sensitivity is different for each light emitted in the same direction (for example, in a direction perpendicular to the surface) from different positions on the surface to be measured of the light source to be measured. The angular unevenness of the measurement sensitivity means that the measurement sensitivity is different for each light emitted from the same position on the surface to be measured of the light source to be measured in different directions. Therefore, in order to reduce measurement errors due to differences in measured positions and measured angles in color measurement, it is necessary to reduce the position unevenness and angle unevenness of measurement sensitivity, which are less susceptible to the position unevenness and angle unevenness of the light emission intensity of the light source to be measured.

In patent document 1, the measurement light is guided by using a light guide body obtained by bundling a plurality of fibers, but in order to reduce the variation in the amount of light and the measurement error, it is necessary to randomly weave each fiber, which is costly. Further, since the filling state, the bending state, the stress state, and the like of the fiber are difficult to control, it is difficult to design the light guide body which is less susceptible to the position unevenness and the angle unevenness of the light emission intensity of the light source to be measured, and therefore it is difficult to reduce the position unevenness and the angle unevenness of the measurement sensitivity.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a photometry device capable of reducing position unevenness and angle unevenness of measurement sensitivity by a configuration using a low-cost light guide member, which is less susceptible to the position unevenness and angle unevenness of the light emission intensity of a light source to be measured.

Means for solving the problems

A photometry device according to an aspect of the present invention includes: a polygonal prism or polygonal frustum light guide member having a polygonal light incident side end face and a polygonal light emergent side end face; an objective optical system for forming an image of the light source to be measured on the light-incident-side end surface of the light guide member; and a light receiving unit that receives light that is incident on the light guide member from the light source to be measured via the objective optical system and is emitted from the light-emitting-side end surface of the light guide member, wherein the light receiving unit has a plurality of sensors having different characteristics and is disposed immediately after the light-emitting-side end surface of the light guide member, or is disposed with a relay optical system interposed therebetween so that the light-emitting-side end surface of the light guide member is conjugate with a light receiving surface of the light receiving unit.

Effects of the invention

In the structure in which light emitted from the light source to be measured is guided to the light receiving portion via the objective optical system and the light guiding member (and the relay optical system, if necessary), the light guiding member has a shape of a mere polygon or a polygon frustum, and therefore, the structure is simple and the cost is low, compared with a conventional light guiding device in which a plurality of fibers are randomly incorporated and guided. The light from the light source to be measured, which is incident on the polygonal-prism-or polygonal-frustum-shaped light guide member, is totally reflected on the side surfaces (surfaces other than the light-incident-side end surface and the light-emitting-side end surface) of the light guide member a number of times corresponding to the incident angle of the light guide member, and is guided and incident on the light receiving portion. Therefore, each sensor of the light receiving unit receives light obtained by mixing light emitted from each position of the surface to be measured of the light source to be measured and light emitted from each angle of the surface to be measured. As a result, even if there are positional irregularities and angular irregularities in the light emission intensity (light emission luminance) of the surface to be measured of the light source to be measured, the light receiving section side can be less susceptible to the positional irregularities and angular irregularities in the measurement sensitivity can be reduced.

Drawings

Fig. 1 is an explanatory diagram showing a schematic configuration of a photometry device according to an embodiment of the present invention and embodiment 1.

Fig. 2A is an oblique view showing an example of the structure of the light guide member of the photometry device.

Fig. 2B is an oblique view showing another configuration example of the light guide member.

Fig. 2C is an oblique view showing another example of the structure of the light guide member.

Fig. 2D is an oblique view showing another example of the structure of the light guide member.

Fig. 3 is a plan view schematically showing a state in which the light-incident-side end surface of the light guide member of fig. 2A is viewed from the measurement range limiting aperture side.

Fig. 4 is a plan view showing the structure of the light receiving unit of the photometry device.

Fig. 5 is a cross-sectional view showing the structure of the light receiving unit.

Fig. 6 is an explanatory view schematically showing an optical path of the light guided in the light guide member.

Fig. 7 is an explanatory view showing an expansion of the optical path of the light beam guided inside the light guide member of fig. 2D.

Fig. 8 is a plan view schematically showing a state in which the light-incident-side end surface of the light guide member of fig. 2B is viewed from the measurement range limiting aperture side.

Fig. 9 is a plan view schematically showing the planar shape of the light receiving portion in the case where the light guide member of fig. 2B is used.

Fig. 10 is a plan view schematically showing a state in which the light-incident-side end surface of the light guide member of fig. 2C is viewed from the measurement range limiting aperture side.

Fig. 11 is a plan view schematically showing the planar shape of the light receiving portion in the case where the light guide member of fig. 2C is used.

Fig. 12 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 2.

Fig. 13 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 3.

Fig. 14 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 4.

Fig. 15 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 5.

Fig. 16 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 6.

Fig. 17 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 7.

Fig. 18 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 8.

Fig. 19 is an explanatory diagram schematically showing a schematic configuration of the photometry device of embodiment 9.

Fig. 20 is an explanatory diagram schematically showing a schematic configuration of the photometry device of comparative example 1.

Fig. 21 is an explanatory diagram schematically showing an example of simulation results of spatial distribution and angular distribution of measurement sensitivity.

Fig. 22 is an explanatory diagram schematically showing a coordinate system of the light source to be measured.

Fig. 23 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor a' which is one of the 4 sensors of comparative example 1.

Fig. 24 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor B' which is one of the 4 sensors of comparative example 1.

Fig. 25 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor C' which is one of the 4 sensors of comparative example 1.

Fig. 26 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor D' which is one of the 4 sensors of comparative example 1.

Fig. 27 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor a, which is one of the 4 sensors of example 1.

Fig. 28 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor B, which is one of the 4 sensors of example 1.

Fig. 29 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor C, which is one of the 4 sensors of example 1.

Fig. 30 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of the sensor D, which is one of the 4 sensors of example 1.

Fig. 31 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 2.

Fig. 32 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 3.

Fig. 33 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 4.

Fig. 34 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 5.

Fig. 35 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 6.

Fig. 36 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 7.

Fig. 37 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 8.

Fig. 38 is an explanatory diagram showing the results of simulation of the spatial distribution and the angular distribution of the measurement sensitivity of any sensor of example 9.

Detailed Description

One embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is an explanatory diagram showing a schematic configuration of a photometry device 1 according to the present embodiment (example 1). The photometry device 1 is configured to have a light guide member 2, an objective optical system 3, a relay optical system 4, and a light receiving unit 5. In the above configuration of the photometry device 1, the surface to be measured LS of the light source to be measured LS will be followed ₀ The emitted light is introduced into the light guide member 2 through the objective optical system 3, guided into the light guide member 2, and then introduced into the light receiving unit 5 through the relay optical system 4. The following describes the components constituting the photometry device 1.

(light guide member)

Fig. 2A is an oblique view showing an example of the structure of the light guide member 2. The light guide member 2 is an optical element having a light-incident-side end face 2a and a light-emergent-side end face 2b, and is configured by a solid (internally filled) rod made of glass in the present embodiment, for guiding light incident from the light-incident-side end face 2a into the inside and discharging the light from the light-emergent-side end face 2 b. In the present embodiment, the light guide member 2 has a quadrangular prism shape in which the light incident side end face 2a and the light exit side end face 2b have the same size (for example, square shape), but the shape is not limited thereto.

Fig. 2B is an oblique view showing another configuration example of the light guide member 2. Fig. 2C is an oblique view showing another configuration example of the light guide member 2. As shown in these figures, the light guide member 2 may be in the shape of a triangular prism in which the light-incident side end face 2a and the light-exit side end face 2b have the same size (for example, a regular triangle), or in the shape of a hexagonal prism in which the light-incident side end face 2a and the light-exit side end face 2b have the same size (for example, a regular hexagon). That is, the light guide member 2 may have a polygonal prism shape in which the light incident side end face 2a and the light exit side end face 2b have the same size.

Fig. 2D is an oblique view showing another configuration example of the light guide member 2. As shown in the figure, the light guide member 2 may have a quadrangular pyramid shape with different sizes of the light entrance side end face 2a and the light exit side end face 2 b. Although not shown, the light-incident-side end face 2a and the light-exit-side end face 2b may have a triangular pyramid shape having different sizes, or the light-incident-side end face 2a and the light-exit-side end face 2b may have a hexagonal pyramid shape having different sizes. That is, the light guide member 2 may have a polygonal frustum shape in which the light incident side end face 2a and the light exit side end face 2b have different sizes.

By the light guide member 2 having the polygonal column or polygonal frustum shape, light incident through the light incident side end face 2a into the light guide member 2 is totally reflected on the side face 2c of the light guide member 2 (interface between the light guide member 2 and air) and guided by the number of times corresponding to the incidence angle with respect to the light incident side end face 2a, and is emitted from the light incident side end face 2 b. The side surface 2c is a surface connecting the light-incident-side end surface 2a and the light-exit-side end surface 2b, and is provided in accordance with the number of vertices (or sides) of the polygons constituting the light-incident-side end surface 2a and the light-exit-side end surface 2 b.

For example, light that has entered at an angle perpendicular or nearly perpendicular to the center of the light-entering side end face 2a (the intersection point of the light-entering side end face 2a and the optical axis of the objective optical system 3) is entered into the light guide member 2 via the light-entering side end face 2a, and then is guided by the side face 2c without being totally reflected, and is emitted from the light-exiting side end face 2 b. Therefore, the "number of times corresponding to the incidence angle" described above also includes 0 times.

The light guide member 2 may be formed of, for example, a hollow tube (light guide) having a polygonal cross section. In this case, by forming a reflective film made of metal on the inner surface of the tube, light incident on the light guide member 2 can be reflected on the inner surface (reflective film) thereof to guide the light. The material constituting the light guide member 2 is not limited to glass, and may be a transparent resin such as acrylic.

(Objective optical system)

The objective optical system 3 is an optical system that reduces the image of the light source LS to be measured on the light-incident-side end face 2a of the light guide member 2. The objective optical system 3 is configured to include a front lens system 31 located on the side of the light source LS to be measured, a rear lens system 32 located on the side of the light guide member 2, a diaphragm AP1 (measurement angle limiting diaphragm) that limits the spread angle of light emitted from the 1 point of the light source LS to be measured, and a diaphragm AP2 (measurement range limiting diaphragm, field diaphragm) that limits the measurement range of the light source LS to be measured.

By the arrangement of the objective lens system 3, the surface LS to be measured of the light source LS to be measured ₀ And the light-incident side end face 2a of the light guide member 2. That is, from the surface LS to be measured of the light source LS to be measured ₀ The light emitted from the above point is collected at a point on the light-incident-side end surface 2a of the light guide member 2. In the present embodiment, the front lens system 31 is configured by 2 lenses and the rear lens system 32 is configured by 3 lenses, but the number of lenses of the front lens system 31 and the rear lens system 32 is not particularly limited as long as the above-described conjugate relationship can be achieved.

The diaphragm AP1 is disposed at the rear focal position of the front lens system 31. Each point in the plane of the diaphragm AP1 (opening) is aligned with the surface LS to be measured of the light source LS to be measured ₀ The angle of light emission corresponds to the above. By arranging the diaphragm AP1, the slave measurement surface LS can be aligned with ₀ The measurement angle (emission angle) of the emitted light is limited appropriately, and is only desiredThe light in the measured angle range is measured. In the present embodiment, the aperture of the diaphragm AP1 has a circular shape, but may have a rectangular shape or another shape.

The aperture AP2 is disposed immediately before the light-incident-side end face 2a of the light guide member 2. Each point in the plane of the diaphragm AP2 (opening) is aligned with the surface LS to be measured of the light source LS to be measured ₀ The points on the table correspond. By disposing the diaphragm AP2, the measurement range (measurement area) of the light source LS to be measured can be limited appropriately, and only the light of the desired measurement range can be measured.

Fig. 3 schematically shows a state when the light-incident-side end face 2A of the light guide member 2 of fig. 2A is viewed from the aperture AP2 side. In the present embodiment, the opening portion AP2a of the aperture AP2 is circular, and its diameter is set to be slightly smaller than the diameter of the inscribed circle of the light-incident-side end face 2a of the light guide member 2. The opening portion AP2a of the diaphragm AP2 may be rectangular or may have another shape. In addition, the arrangement of the diaphragm AP2 can be omitted. In this case, the surface to be measured LS of the light source to be measured LS ₀ The measurement range of (2) is similar to the shape of the light-incident-side end face 2a of the light guide member 2.

(Relay optical system)

The relay optical system 4 is an optical system that guides light emitted from the light-emitting-side end surface 2b of the light guide member 2 to the light-receiving surface 5a of the light-receiving portion 5 so that the light-emitting-side end surface 2b of the light guide member 2 is conjugate with the light-receiving surface 5a. That is, by the arrangement of the relay optical system 4, light emitted from a certain point on the light-emitting-side end face 2b of the light guide member 2 is collected at a certain point on the light-receiving surface 5a of the light-receiving portion 5, and an image of the light-emitting-side end face 2b of the light guide member 2 is enlarged and formed on the light-receiving surface 5a of the light-receiving portion 5. In the present embodiment, the relay optical system 4 is configured by 4 lenses, but the number of lenses of the relay optical system 4 is not particularly limited as long as the above-described conjugate relationship can be achieved.

(light receiving section)

The light receiving unit 5 receives light that has entered the light guide member 2 from the light source LS to be measured via the objective optical system 3 and has exited from the light exit side end surface 2b of the light guide member 2. The light receiving unit 5 is composed of a plurality of sensors 51 having different characteristics. In the present embodiment, the plurality of sensors 51 of the light receiving unit 5 each have measurement sensitivity corresponding to the color matching function X, Y, Z. The structure of the light receiving unit 5 is described in detail below.

Fig. 4 is a plan view showing the structure of the light receiving unit 5, and fig. 5 is a cross-sectional view showing the structure of the light receiving unit 5. The light receiving unit 5 includes 4 sensors 51 (51 a to 51 d). Each sensor 51 is composed of a light receiving element 52 and an optical filter 53. Each light receiving element 52 is constituted by, for example, a silicon photodiode, and an electric signal corresponding to the amount of light received by light is output to a circuit (not shown) of a subsequent stage. The light receiving surface 5a of each light receiving element 52 is square or rectangular, and is located at four corners of 1 quadrangle. Therefore, the plurality of sensors 51 of the light receiving unit 5 can be said to have the quadrangular light receiving surfaces 5a located at the four corners of 1 quadrangle, respectively. Each light receiving surface 5a may be a polygon other than a quadrangle (for example, a triangle), or may be a circle.

The optical filter 53 of each sensor 51 has an optical characteristic of transmitting light in a predetermined wavelength band, is formed to have a larger size than the light receiving element 52, and is disposed on the light incident side of the light receiving element 52. In the present embodiment, the optical filters 53 of 3 sensors 51 (for example, the sensors 51a to 51 c) out of the 4 sensors 51 are each composed of optical filters 53X, 53Y, 53Z that transmit light of a wavelength band corresponding to the color matching function X, Y, Z. Accordingly, the 3 sensors 51 each have measurement sensitivity corresponding to the color matching function X, Y, Z. The light transmitted through the optical filters 53X, 53Y, 53Z of the 3 sensors 51 is received by the corresponding light receiving elements 52. The color or brightness can be measured by processing the electric signals output from the light receiving elements 52 by a circuit.

That is, the plurality of sensors 51 of the light receiving unit 5 each have measurement sensitivity corresponding to the color matching function X, Y, Z, and thus, based on an electric signal (corresponding to a 3 stimulus value of XYZ) output from each sensor 51 (each light receiving element 52), the ratio of each color of red (R), green (G), and blue (B) or the luminance (e.g., (r+g+b)/3) can be obtained by a circuit. Accordingly, a color luminance meter (colorimeter) that obtains color or luminance can be realized.

The optical filter 53 of the remaining sensor 51 (for example, the sensor 51 d) out of the 4 sensors 51 is constituted by an optical filter 53Y that transmits light of a wavelength band corresponding to the color matching function Y. The light receiving element 52 that receives the light transmitted through the optical filter 53Y is connected to, for example, a flicker detection circuit. Accordingly, the flicker can be detected based on the electric signal output from the light receiving element 52.

One of the 2 optical filters 53Y may be an optical filter that transmits infrared rays, for example. In this case, since the 4 types of optical filters 53 are arranged, 4 types of optical characteristics can be measured simultaneously.

In the present embodiment, the optical characteristics of 3 optical filters 53X, 53Y, 53Z out of the 4 optical filters 53 are different from each other, but at least 2 optical filters 53 may have different characteristics from each other (not all the characteristics of the optical filters 53 may be the same). The plurality of sensors 51 of the light receiving unit 5 each include a light receiving element 52 having a square or rectangular light receiving surface 5a, and an optical filter 53 disposed on the light incident side of the light receiving element 52, and at least 2 pieces of the optical filters 53 have different characteristics from each other, whereby the plurality of characteristic sensors 51 can be simply and uniformly disposed as shown in fig. 4.

Each sensor 51 is accommodated in and held by a recess 54a of the holding member 54 such that the optical filter 53 is positioned closer to the light incident side than the light receiving element 52, and the light receiving element 52 and the optical filter 53 are arranged with a gap therebetween. The concave portion 54a is stepped in shape with an opening diameter that narrows stepwise from the arrangement side of the optical filter 53 toward the arrangement side of the light receiving element 52, and therefore the optical filter 53 and the light receiving element 52 can be accommodated in the concave portion 54a so as to be in the above positional relationship.

The holding member 54 serves as a light blocking wall that defines the adjacent sensor 51. That is, since the holding member 54 serves as a light blocking wall between the adjacent 2 sensors 51, the light passing through the optical filter 53 of one of the adjacent sensors 51 can be prevented from entering the light receiving element 52 of the other of the adjacent sensors 51, and the measurement error can be reduced.

In addition, as in the present embodiment, in a configuration in which the plurality of sensors 51 (the optical filter 53 and the light receiving element 52) are arranged and held by the holding member 54, the arrangement area of the plurality of sensors 51 is enlarged. However, since the image of the light-emitting-side end face 2b of the light guide member 2 is enlarged and formed on the light-receiving surface 5a by the relay optical system 4, a sufficiently large illumination range can be ensured for each sensor 51 even in a configuration in which the plurality of sensors 51 are held by the holding member 54.

As shown in fig. 4, the irradiation range R when the light emitted from the light emitting side end surface 2b of the light guide member 2 irradiates the light receiving unit 5 includes the light receiving ranges of the plurality of sensors 51 of the light receiving unit 5, that is, all the light receiving surfaces 5a of the light receiving elements 52. Accordingly, even if the position of the irradiation range R (imaging range of the image of the light emitting side end face 2b of the light guide member 2) is shifted with respect to each light receiving surface 5a due to errors (positional deviation of each component, inclination deviation), changes in the environment (temperature change, humidity change, vibration, impact, etc.) and the like of the optical system at the time of assembling the optical system, a stable measurement can be performed due to a small change in the light receiving amount (measurement value).

In particular, in the present embodiment, the light-incident-side end face 2A and the light-exit-side end face 2b of the light guide member 2 are quadrangular (see fig. 2A), and the plurality of sensors 51 of the light receiving section 5 have quadrangular light receiving surfaces 5a located at four corners of 1 quadrangle, respectively. Accordingly, the light emitted from the light-emitting-side end surface 2b of the light guide member 2 can be efficiently guided to a desired range (each light-receiving surface 5 a) of the light-receiving portion 5. Therefore, since the light utilization efficiency is improved (since most of the illumination light can be received), measurement of a high S/N (Signal-to-Noise) ratio can be performed.

As the optical filter 53, an interference film filter having an interference film formed on a glass circuit board can be used. In the case of using an interference film filter, although the spectral transmittance of light changes due to the incidence angle of light to the interference film, in the present embodiment, the image of the light-outgoing side end face 2b of the light guide member 2 is enlarged and imaged on the light-receiving surface 5a by the relay optical system 4, and therefore the incidence angle of light to each sensor 51 becomes small. Accordingly, the change in spectral transmittance due to the light incidence angle on the interference film filter can be reduced.

As the optical filter 53, a colored glass filter that absorbs light in a specific wavelength band, an ND (Neutral Density) filter that attenuates light in a broad wavelength band, a linear polarizing plate, a wavelength plate, and the like can be used. In addition, a plurality of optical filters 53 may be disposed on the light incident side of 1 light receiving element 52.

The optical filters 53 may be all made of the same filter. However, in this case, in order to make the characteristics different among the plurality of sensors 51, it is necessary to use a different sensor as the light receiving element 52. For example, by combining and using a silicon photodiode for visible light and an InGaAs photodiode for infrared light, or by combining and using a light receiving element capable of high-sensitivity measurement and a light receiving element capable of high-speed measurement, various optical characteristics can be measured simultaneously while using the same optical filter 53.

The number of sensors 51 constituting the light receiving unit 5 is not limited to 4 in the present embodiment. For example, by appropriately arranging 9 sensors 51 in 3 rows and 3 columns, or by arranging 16 sensors 51 in 4 rows and 4 columns, or the like, more optical characteristics can be measured simultaneously.

(effect of reducing the position unevenness and angle unevenness of the light guide member on measurement sensitivity)

Next, the effect that the position unevenness and the angle unevenness of the measurement sensitivity can be reduced by using the light guide member 2 of the present embodiment will be described.

In the structure of the light guide member 2 using the shape of a polygon prism or a polygon frustum as in the present embodiment, as described above, the light emitted from the light source to be measured LS and introduced into the light guide member 2,the total reflection is repeated on the side surface 2c of the light guide member 2 at a number of times corresponding to the incidence angle on the light incidence side end surface 2a, and is emitted from the light emission side end surface 2 b. In this configuration, if a certain 1 point of the light-emitting side end face 2b is considered, the above 1 point becomes illuminated with light from each point of the light-entering side end face 2a of the light guide member 2. In addition, because the surface LS to be measured of the light source LS to be measured ₀ The light-emitting side end face 2b of the light guide member 2 is conjugated to the light-receiving surface 5a of the light-receiving portion 5 through the relay optical system 4 by being conjugated to the light-emitting side end face 2a of the light guide member 2 through the objective optical system 3, so that finally, the light from each point of the light source LS to be measured illuminates each sensor 51 of the light-receiving portion 5 through the light guide member 2. That is, even if the surface LS to be measured of the light source LS to be measured ₀ The light emission intensity (brightness) of each sensor 51 is mixed with the surface LS to be measured by the light guide member 2, and the positions of the sensors are not uniform ₀ Light received by the light of each position of (a) is not easily received by the surface LS to be measured ₀ Influence of position unevenness. Accordingly, the position unevenness of the measurement sensitivity can be reduced in each sensor 51, and stable measurement can be performed.

In the configuration using the light guide member 2 having the shape of a polygon or a polygon frustum, the angle at which light is emitted to the light-incident-side end surface 2a of the light guide member 2 changes according to the angle at which light is emitted from the light source to be measured LS. The light incident into the light guide member 2 through the light incident side end surface 2a is repeatedly totally reflected on the side surface 2c of the light guide member 2a number of times corresponding to the angle thereof, and reaches each position of the light emitting side end surface 2b (position corresponding to the incident angle of the light guide member 2). Therefore, as described above, if a certain 1 point of the light-emitting side end face 2b is considered, the above 1 point becomes illuminated with light of various angles. Since the light from the light source to be measured LS is emitted at an angle corresponding to the angle of incidence of the light on the light-incident-side end face 2a of the light guide member 2, the light-emitting-side end face 2b of the light guide member 2 is conjugated to the light-receiving surface 5a of the light-receiving portion 5, and finally, the light emitted from the light source to be measured LS at each angle illuminates each sensor 51 of the light-receiving portion 5 via the light guide member 2. That is, even if measured Measured surface LS of light source LS ₀ The light emission intensity (brightness) of each sensor 51 is mixed with the light guide member 2 to be measured from the surface LS to be measured ₀ Light emitted from each angle is received, and is not easily received by the surface LS to be measured ₀ The influence of uneven angle. Accordingly, the angular unevenness of the measurement sensitivity can be reduced in each sensor 51, and stable measurement can be performed.

Further, since the light guide member 2 has a shape of a mere polygon prism or a polygon frustum (see fig. 2A to 2D), it has a simple structure and low cost compared with a conventional light guide in which a plurality of fibers are randomly woven and guided. Therefore, the effect of reducing the position unevenness and the angle unevenness of the measurement sensitivity can be obtained with a simple configuration using the light guide member 2 at low cost. In particular, in the present embodiment, since the light receiving unit 5 has the plurality of sensors 51 having different characteristics as described above, the color or the luminance can be measured, and therefore the above-described effects can be obtained in the color luminance meter that measures such color or luminance.

Fig. 6 is an explanatory diagram schematically showing the optical path of the light beam guided inside the light guide member 2. The surface LS to be measured of the light source LS to be measured is made to pass through an objective optical system 3 (refer to FIG. 1) ₀ Since the image of (a) is reduced and formed on the light-incident-side end face 2a of the light guide member 2, the thin light guide member 2 (diameter D of inscribed circle of the light-incident-side end face 2a can be used ₁ And diameter D of inscribed circle of light-emitting side end face 2b ₂ A smaller light guide member), and the incident angle θ of the light on the light-incident-side end face 2a of the light guide member 2 becomes larger than the incident angle of the light emitted from the light source LS to be measured (therefore, the refraction angle θ inside the light guide member 2 _P And also becomes larger). As can be seen from fig. 6, the larger the incident angle θ of light on the light incident side end face 2a (refraction angle θ _P Larger), or diameter D ₁ D (D) ₂ The smaller the light incident on the light guide member 2, the more the number of reflections on the side surface 2c increases.

In the present embodiment, D ₁ ＝D ₂ Emits from the measured light source LSOf the light rays incident on the light-incident-side end face 2a of the light guide member 2, the light ray LT having the largest angle θ with respect to the optical axis AX is reflected on the side face 2c of the light guide member 2 approximately by the number of times (Ltan θ _P )/D ₁ Or (Ltan theta) _P )/D ₂ The performance is presented. Wherein when n is _P When the refractive index of the light guide member 2 is set to be the refractive angle θ _P Is satisfied with n _P sinθ _P Angle=sinθ. The optical axis AX is an axis obtained by connecting the center of the inscribed circle of the light-incident side end surface 2a and the center of the inscribed circle of the light-exit side end surface 2b of the light guide member 2, and is coaxial with the optical axes of the objective optical system 3 and the relay optical system 4.

As described above, in the configuration of the present embodiment, when a certain 1 point of the light exit side end surface 2a of the light guide member 2 is considered, the above 1 point is illuminated with light of each angle emitted from the light source to be measured LS, and the influence of the angle unevenness of the light source to be measured LS can be reduced. If the light is reflected inside the light guide member 2, the angle of the light is reversed, and therefore if the number of reflections of the light increases, the above 1 point becomes illuminated with more light of each angle. Therefore, the influence of the angular unevenness of the light source LS to be measured can be reduced more effectively, the angular unevenness of the measurement sensitivity can be reduced, and more stable measurement can be performed.

In addition, when the number of reflections in the light guide member 2 is set to be constant, the refraction angle θ _P The larger D ₁ Or D ₂ The smaller the length L of the light guide member 2 in the optical axis AX direction can be made smaller. In this case, the photometry device 1 can be miniaturized.

(regarding the number of reflections when using a light guide member having a polygonal pyramid)

Fig. 7 is an explanatory diagram showing the expansion of the optical path of the light beam guided in the light guide member 2 when the polygonal frustum-shaped light guide member 2 shown in fig. 2D is used as the light guide member 2. In the light guide member 2, the light incident side end face 2a and the light exit side end face 2b are square in shape, but the light exit side end face 2b has a larger area than the light incident side end face 2 a. In the case of using such a polygonal pyramid light guide member 2, even if the light receiving portion 5 is disposed immediately after the light exit side end face 2b of the light guide member 2 (even without interposing the relay optical system 4), the light emitted from the light exit side end face 2b of the light guide member 2 can be guided to the entire light receiving portion 5. By disposing the light receiving unit 5 immediately after the light emitting side end surface 2b of the light guide member 2 in this manner, the arrangement of the relay optical system 4 is omitted, and thus the light measuring device 1 can be realized at low cost.

Here, the number of reflections of light guided inside when the light guide member 2 having a polygonal pyramid shape is used can be considered as follows. That is, when the polygonal frustum-shaped light guide member 2 is used, the approximate number of reflections of the light LT having the largest angle θ with respect to the optical axis AX, out of the light emitted from the light source LS to be measured and incident on the light incident side end face 2a of the light guide member 2, on the side face 2c of the light guide member 2 is represented by α/β. In fig. 7, α is an angle (°) between a straight line connecting point a and point O and the optical axis AX, and β is an angle (°) 2 times the angle between the side surface 2c of the light guide member 2 and the optical axis AX in a cross section including the optical axis AX. Here, the point O is a point intersecting the optical axis AX when the side surface 2c of the light guide member 2 is extended in a cross section including the optical axis AX, and the point a is a point where the light LT is refracted at the light incident side end surface 2a of the light guide member 2 (an angle formed with the optical axis AX is θ _P ) A straight line (dotted line LP) extending from the center of the straight line is a point O and the radius is L ₀ Is the point at which the circles intersect. Specifically, α and β are angles satisfying the following relational expression. That is to say that the first and second,

L ₀ sinα＝{L-L ₀ (1-cosα)}tanθ _P

tan(β/2)＝(D ₂ -D ₁ )/2L

L ₀ ＝D ₂ L/(D ₂ -D ₁ )

n _P sinθ _P ＝sinθ

l: length (mm) of the light guide member 2 in the optical axis AX direction

θ: the maximum value (°) of the angle formed by the light ray incident on the center of the light-incident-side end face 2a of the light guide member 2 and the normal line of the light-incident-side end face 2a

D ₁ : diameter (mm) of inscribed circle of light incident side end face 2a of light guide member 2

D ₂ : diameter (mm) of inscribed circle of light-emitting side end face 2b of light guide member 2

n _P : refractive index of the light guide member 2.

If α/β > 1, that is, if the number of reflections of the light LT on the side face 2c of the light guide member 2 is at least 1, the light LT can be reflected on the side face 2c to be measured from the surface LS to be measured ₀ Light emitted from each position of (a) and from the surface (LS) to be measured ₀ The light emitted at each angle is mixed in the light guide member 2. Therefore, the influence of the position unevenness and the angle unevenness of the light source LS to be measured can be reduced, and the position unevenness and the angle unevenness of the measurement sensitivity can be reduced. In particular, α/β > 2 is preferable because the light LT is reflected on the side surface 2c a plurality of times, and the influence of the position unevenness and the angle unevenness of the light source LS to be measured can be reliably reduced, and the position unevenness and the angle unevenness of the measurement sensitivity can be reliably reduced. In addition, from the viewpoint of more reliably obtaining the effects of the present embodiment, α/β > 4 is more preferable, α/β > 7 is more preferable, and α/β > 10 is still more preferable, from the results of examples described later.

In addition, in the case of alpha < 1 and beta < 1,

α≒(L/L ₀ )tanθ _P ＝{(D ₂ -D ₁ )/D ₂ }/tanθ _P

β≒(D ₂ -D ₁ )/L

therefore: alpha/beta ∈ (Ltan θ) _P )/D ₂ . That is, in this case, α/β is equal to D ₁ ＝D ₂ The number of reflections is approximately the same in the case of (a).

(relationship between other shapes of the light guide member and the light receiving portion)

Fig. 8 schematically shows a state when the prism-shaped light guide member 2 shown in fig. 2B is used and the light-incident-side end face 2a is viewed from the aperture AP2 side. As shown in the figure, even when the prism-shaped light guide member 2 is used, the size of the circular opening portion AP2a of the aperture AP2 may be set slightly smaller than the inscribed circle of the light-incident side end face 2a of the light guide member 2.

Fig. 9 schematically shows the planar shape of the light receiving portion 5 in the case where the light guide member 2 of fig. 2B is used. The light receiving unit 5 may be configured by 3 sensors 51 (51 a to 51 c) having a circular shape in a plan view, and each sensor 51 may be located at a position corresponding to each vertex of 1 regular triangle. Since the light-emitting-side end face 2b of the light guide member 2 has a regular triangle shape, the irradiation range R when the light emitted from the light-emitting-side end face 2b of the light guide member 2 irradiates the light receiving portion 5 also becomes a regular triangle shape including the respective light receiving ranges of all 3 sensors 51 of the light receiving portion 5.

Fig. 10 schematically shows a state when the light-incident-side end face 2a of the hexagonal prism-shaped light guide member 2 shown in fig. 2C is viewed from the aperture AP2 side. As shown in the figure, even when the light guide member 2 having a hexagonal prism shape is used, the size of the circular opening portion AP2a of the aperture AP2 may be set to be slightly smaller than the inscribed circle of the light-incident-side end face 2a of the light guide member 2.

Fig. 11 schematically shows the planar shape of the light receiving portion 5 in the case where the light guide member 2 of fig. 2C is used. The light receiving unit 5 may be configured to be composed of 7 sensors 51 (51 a to 51 g) each having a square or rectangular shape in plan view, and each sensor 51 may be located at a position corresponding to each vertex and center of 1 regular hexagon. Since the light-emitting-side end face 2b of the light guide member 2 has a regular hexagonal shape, the irradiation range R when the light emitted from the light-emitting-side end face 2b of the light guide member 2 irradiates the light receiving portion 5 also becomes a regular hexagonal shape including the respective light receiving ranges of all 7 sensors 51 of the light receiving portion 5.

Example (example)

Next, specific examples of the present invention will be described with reference to examples 1 to 9. For comparison with each example, a comparative example will be described.

Fig. 12 to 19 schematically show the schematic structures of the photometry devices 1 of embodiments 2 to 9, respectively. Fig. 20 schematically shows a schematic configuration of the photometry device 1' of comparative example 1. The structure of the photometry device 1 of embodiment 1 is shown in fig. 1. In fig. 1, 12 to 20, the scale of each photometry device is adjusted and illustrated (scale is not the same) for convenience.

The photometry device 1 of example 2 has the same configuration as the photometry device 1 of example 1 except that the position of the exit pupil is shifted toward the side of the measurement light source LS as compared with the photometry device 1 of example 1. Here, the position of the exit pupil refers to the position of an image formed by the diaphragm AP 1.

The photometry device 1 of example 3 has the same configuration as the photometry device 1 of example 2 except that the position of the exit pupil is shifted toward the side of the measurement light source LS as compared with the photometry device 1 of example 2. The photometry device 1 of example 4 has the same configuration as the photometry device 1 of example 1 except that the position of the exit pupil is shifted toward the light receiving section 5 side as compared with the photometry device 1 of example 1.

The photometry device 1 of example 5 has the same configuration as the photometry device 1 of example 1 except that the length of the optical axis direction of the light guiding member 2 is increased and the number of reflections (α/β) of the light beam incident on the inside of the light guiding member 2 on the side surface 2c is increased as compared with the photometry device 1 of example 1.

The photometry device 1 of example 6 is similar to the photometry device 1 of example 1 except that the quadrangular prism-shaped light guiding member 2 of the photometry device 1 of example 1 is replaced with a quadrangular prism-shaped light guiding member 2 (see fig. 2D), the relay optical system 4 is not disposed, and the light receiving section 5 is disposed immediately after the light emitting side end surface 2b of the light guiding member 2.

The photometry device 1 of example 7 is similar to the photometry device 1 of example 1 except that the quadrangular prism-shaped light guiding member 2 of the photometry device 1 of example 1 is replaced with a triangular prism-shaped light guiding member 2 (see fig. 2B), and the light receiving section 5 (see fig. 9) having 3 circular sensors 51 is used instead of the light receiving section 5 having 4 quadrangular sensors 51. The photometry device 1 of example 8 is similar to the photometry device 1 of example 1 except that the quadrangular prism-shaped light guiding member 2 of the photometry device 1 of example 1 is replaced with a hexagonal prism-shaped light guiding member 2 (see fig. 2C), and the light receiving section 5 (see fig. 11) having 7 square-shaped sensors 51 is used instead of the light receiving section 5 having 4 square-shaped sensors 51.

The photometry device 1 of example 9 has the same configuration as the photometry device 1 of example 1 except that the length of the optical axis direction of the light guiding member 2 is shortened and the number of reflections (α/β) of the light beam incident on the inside of the light guiding member 2 on the side surface 2c is reduced as compared with the photometry device 1 of example 1.

The photometry device 1' of comparative example 1 has the same configuration as that of the photometry device 1 of example 1 except that the arrangement of the light guiding component 2 in the photometry device 1 of example 1 is omitted.

Table 1 shows the parameters of examples 1 to 9 and comparative example 1.

TABLE 1

(evaluation)

In order to confirm the effects of the structures of examples 1 to 9 and comparative example 1, the spatial distribution and the angular distribution of the measurement sensitivity of at least 1 sensor 51 of the light receiving unit 5 were simulated. The simulation of the spatial distribution and the angular distribution of the measurement sensitivity is that of the surface LS to be measured of the light source LS to be measured ₀ When the surface light source is uniformly and completely diffused, the surface LS to be measured is ₀ To what extent the light emitted from each position reaches the light receiving element and from the surface LS to be measured ₀ The degree to which the light emitted in each direction reaches the light receiving element was simulated using optical software. For example, fig. 21 schematically shows an example of simulation results of the spatial distribution and the angular distribution of the measurement sensitivity of 1 sensor 51. In these distributions, the white portion exhibits relatively high measurement sensitivity, and the black portion exhibits relatively low measurement sensitivity.

Fig. 22 schematically shows a light source LS (surface to be measured LS ₀ ) Is a coordinate system of (a). The position in the horizontal direction (x direction) and the position in the vertical direction (y direction) of the spatial distribution of the measurement sensitivity shown in fig. 21 are respectively identical to the surface LS to be measured ₀ The position in the horizontal direction (X direction) and the position in the vertical direction (Y direction) correspond to each other. The angle (θx) in the horizontal direction and the angle (θy) in the vertical direction of the angular distribution of the measurement sensitivity are respectively equal to the angle of the outgoing light beam with respect to the surface to be measured LS ₀ The angle (thetax) of the normal (Z direction) in the horizontal direction (X direction) and the angle (thetay) of the normal (Y direction) in the vertical direction (Y direction) correspond.

Fig. 23 to 26 show results obtained by simulating the spatial distribution and the angular distribution of measurement sensitivities of the 4 sensors 51 (referred to herein as sensors a ', B', C ', D') of comparative example 1. The above-mentioned sensors a ', B', C ', and D' correspond to the sensors 51a, 51B, 51C, and 51D of fig. 4, respectively. From these graphs, in comparative example 1, the spatial distribution of measurement sensitivity was very uneven between the sensors a 'to D'.

In contrast, fig. 27 to 30 show results obtained by simulating the spatial distribution and the angular distribution of the measurement sensitivities of the 4 sensors 51 (referred to herein as sensor a, sensor B, sensor C, and sensor D) of the light receiving unit 5 of example 1. The above-mentioned sensor a, sensor B, sensor C, and sensor D correspond to the sensor 51a, sensor 51B, sensor 51C, and sensor 51D of fig. 4, respectively. From these figures, it is clear that the same distribution can be obtained as the spatial distribution of the measurement sensitivity between the sensors a to D, and the same distribution can be obtained as the angular distribution of the measurement sensitivity. Therefore, it is clear that in example 1, the spatial distribution and the angular distribution of the measurement sensitivity can be made uniform simultaneously between the plurality of sensors.

Fig. 31 to 38 show junctions obtained by simulating the spatial distribution and the angular distribution of the measurement sensitivity of any one of the plurality of sensors 51 (herein, sensor a) constituting the light receiving unit 5 of examples 2 to 9And (5) fruits. The sensor a corresponds to the sensor 51a of fig. 4 (examples 2 to 6 and 9), the sensor 51a of fig. 9 (example 7), or the sensor 51a of fig. 11 (example 8). In examples 2 to 9, the spatial distribution of the measurement sensitivity was almost uniform in the measurement range in the same manner as in example 1. By the arrangement of the light guide member 2, each of the sensors 51 of examples 1 to 9 receives light by averaging the weights of the measurement sensitivity distribution, and therefore even the surface LS to be measured of the light source LS to be measured is obtained ₀ The light-emitting intensity (luminance) of the light-receiving section 5 is also reduced by the influence of the position unevenness, and stable measurement can be performed.

In examples 1 to 9, the angular distribution of the measurement sensitivity was slightly different from one example to another, but in any one example, the angular distribution of the measurement sensitivity was distributed over a wide range of the measurement range. By the arrangement of the light guide member 2, each of the sensors 51 of examples 1 to 9 receives light by averaging the weights of the measurement sensitivity distribution, and therefore even the surface LS to be measured of the light source LS to be measured is obtained ₀ The light emission intensity (luminance) of (a) has an angular unevenness, and the influence of the angular unevenness can be reduced in the light receiving section 5 to perform stable measurement.

From the simulation results of each of examples 1 to 9 described above, the spatial distribution and the angular distribution of the measurement sensitivity vary according to the length L and the exit pupil position of the light guide member 2. Therefore, by adjusting the length L or the exit pupil position of the light guide member 2, the photometry device 1 having uniformity of a desired measurement sensitivity can be designed.

(others)

As described above, the photometry device according to the present embodiment can be expressed as follows.

The photometry device of the present embodiment includes: a polygonal prism or polygonal frustum light guide member having a polygonal light incident side end face and a polygonal light emergent side end face; an objective optical system for forming an image of the light source to be measured on the light-incident-side end surface of the light guide member; and a light receiving unit that receives light that is incident on the light guide member from the light source to be measured via the objective optical system and is emitted from the light-emitting-side end surface of the light guide member, wherein the light receiving unit has a plurality of sensors having different characteristics and is disposed immediately after the light-emitting-side end surface of the light guide member, or is disposed with a relay optical system interposed therebetween so that the light-emitting-side end surface of the light guide member is conjugate with a light receiving surface of the light receiving unit.

In the above photometry device, the objective optical system may include a front side lens system located on the side of the light source to be measured, a rear side lens system located on the side of the light guide member, and a diaphragm for limiting a spread angle of light emitted from 1 point of the light source to be measured, and the diaphragm may be disposed at a rear side focal position of the front side lens system.

Preferably, the photometry device satisfies α/β > 2.

Wherein,

L ₀ sinα＝{L-L ₀ (1-cosα)}tanθ _P

tan(β/2)＝(D ₂ -D ₁ )/2L

L ₀ ＝D ₂ L/(D ₂ -D ₁ )

n _P sinθ _P ＝sinθ

l: length (mm) of the light guide member in the optical axis direction

θ: a maximum value (°) of an angle formed by a light ray incident to a center of a light-incident side end surface of the light guide member and a normal line of the light-incident side end surface

D ₁ : diameter (mm) of inscribed circle of light incident side end face of the light guide member

D ₂ : diameter (mm) of inscribed circle of light-emitting side end face of the light guide member

n _P : refractive index of the light guide member

At D ₁ ＝D ₂ In the case of (a) the number of the cells,

α/β＝Ltanθ _p /D ₂ ＞2。

in the above-described photometry device, the plurality of sensors of the light receiving section may include light receiving elements each having a square or rectangular light receiving surface, and optical filters disposed on a light incident side of the light receiving elements, and at least 2 of the optical filters may have different characteristics from each other.

In the above-described photometry device, the irradiation range when the light emitted from the light emitting side end surface of the light guide member irradiates the light receiving section may include the respective light receiving ranges of all the plurality of sensors of the light receiving section.

In the above photometry device, the plurality of sensors of the light receiving section may have measurement sensitivities corresponding to the color matching functions X, Y, Z, respectively.

In the above-described photometry device, the light-incident-side end surface and the light-exit-side end surface of the light guide member may be quadrangular, and the plurality of sensors of the light receiving section may have light receiving surfaces of quadrangles located at four corners of 1 quadrangle, respectively.

Although the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications may be added thereto without departing from the spirit of the present invention.

Industrial applicability

The invention can be used, for example, in a color brightness meter.

Reference numerals illustrate:

1. photometry device

2. Light guide member

2a light incident side end face

2b light-emitting side end face

2c side

3. Objective optical system

4. Relay optical system

5. Light receiving part

5a light-receiving surface

31. Front lens system

32. Rear lens system

51. Sensor for detecting a position of a body

52. Light receiving element

53. Optical filter

AP1 diaphragm

LS measured light source

Claims

1. A photometry device is provided with:

a polygonal prism or polygonal frustum light guide member having a polygonal light incident side end face and a polygonal light emergent side end face;

an objective optical system for forming an image of the light source to be measured on the light-incident-side end surface of the light guide member; and

a light receiving unit that receives light that has been incident on the light guide member from the light source to be measured via the objective optical system and has been emitted from the light-emitting-side end surface of the light guide member,

the light receiving section has a plurality of sensors having different characteristics and is disposed immediately after the light emitting side end surface of the light guide member or is disposed with a relay optical system interposed therebetween so that the light emitting side end surface of the light guide member is conjugate with the light receiving surface of the light receiving section,

the photometry device satisfies alpha/beta > 2,

wherein,

L ₀ sinα＝{L-L ₀ (1-cosα)}tanθ _P

tan(β/2)＝(D ₂ -D ₁ )/2L

L ₀ ＝D ₂ L/(D ₂ -D ₁ )

n _P sinθ _P ＝sinθ

l: the length of the light guide member in the optical axis direction is in mm

θ: the maximum value of the angle formed by the light incident to the center of the light incident side end face of the light guide member and the normal line of the light incident side end face is expressed as a unit of °

D ₁ : the diameter of the inscribed circle of the light incidence side end face of the light guide member is in mm

D ₂ : the light guide memberThe diameter of the inscribed circle of the light-emitting side end face of (2) is in mm

n _P : refractive index of the light guide member

Alpha: an angle between a straight line connecting the point A and the point O and an optical Axis (AX) of the light guide member is expressed in DEG,

beta: an angle of 2 times an angle formed by a side surface of the light guide member and the optical Axis (AX) in a section including the optical Axis (AX) is expressed in degrees

Point O: a point intersecting the optical Axis (AX) when the side surface of the light guide member is elongated in a cross section including the optical Axis (AX)

Point A: a straight line extending a light ray refracted at the light-incident-side end face of the light guide member from a light ray incident on the center of the light-incident-side end face of the light guide member at an angle θ with respect to the normal line of the light-incident-side end face, the straight line having a center of the point O and a radius L ₀ At the point at which the circles of the refracted ray intersect with the optical Axis (AX) at an angle of θ _P

At D ₁ ＝D ₂ In the case of (a) the number of the cells,

α/β＝Ltanθ _p /D ₂ ＞2。

2. the photometry device of claim 1,

the objective optical system includes a front lens system located on the light source side to be measured, a rear lens system located on the light guide member side, and a diaphragm for limiting the spread angle of light emitted from 1 point of the light source to be measured,

The diaphragm is disposed at a rear focal position of the front lens system.

3. The photometry device of any one of claim 1 to 2,

the plurality of sensors of the light receiving unit each include a light receiving element having a square or rectangular light receiving surface, and an optical filter arranged on a light incident side of the light receiving element,

at least 2 of the optical filters differ in characteristics from each other.

4. The photometry device of any one of claim 1 to 3,

the irradiation range of the light emitted from the light emitting side end surface of the light guide member when the light irradiates the light receiving portion includes the respective light receiving ranges of all the plurality of sensors of the light receiving portion.

5. The photometry device of any one of claim 1 to 4,

the plurality of sensors of the light receiving unit each have a measurement sensitivity corresponding to the color matching function X, Y, Z.

6. The photometry device of any one of claim 1 to 5,

the light-incident-side end face and the light-emergent-side end face of the light guide member are quadrangular,

the plurality of sensors of the light receiving section have quadrangular light receiving surfaces located at four corners of 1 quadrangle, respectively.