JP7415923B2 - Photometric device - Google Patents

Description

The present invention relates to a photometric device that measures the characteristics of a light source to be measured, and particularly to a photometric device such as a color luminance meter that measures the brightness and chromaticity of light emitted from the light source to be measured.

In a photometric device such as a color luminance meter, in order to measure color, measurement light is divided into three parts and received by each sensor. As a means for dividing measurement light into three parts, for example, Patent Document 1 proposes a light guide in which a large number of optical fibers are bundled. This light guide is configured such that the incident side of the measurement light is combined into one fiber bundle, and the output side is divided into three fiber bundles. The light emitted from the end faces of the three fiber bundles enters the light-receiving element through filters that have the characteristic of transmitting red (R), green (G), and blue (B) light, respectively.

The plurality of optical fibers are formed in a bundle so that the image forming positional relationship of the image forming light beam formed on the end face on the incident side of the measurement light is pseudo-random. As a result, the image-forming light beams emitted from the end faces of the three fiber bundles on the light-emitting side and incident on each light-receiving element are mixed in a pseudo-random manner, so that unevenness in the amount of image-forming light beams is reduced.

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

By the way, when measuring color using a photometric device, the photometric device is brought into contact with the surface to be measured of the object to be measured (the light source to be measured), or brought close to the surface without contact, and the light is emitted from a predetermined area of the surface to be measured within a predetermined angular range. This is done by receiving the reflected light with a photometric device. At this time, if there is any unevenness (positional unevenness, angular unevenness) in the light emission intensity (emission brightness) of the surface to be measured due to the light emission position and the light emission angle, the photometric device will also be affected by this. When the positional and angular unevenness of measurement sensitivity increases on the photometric device side due to the above-mentioned influence, the difference in measured values (measurement error) increases due to the difference in the measuring position and measuring angle. Note that the positional unevenness in measurement sensitivity refers to the difference in measurement sensitivity for each light emitted from different positions on the surface to be measured of the light source to be measured in the same direction (for example, a direction perpendicular to the surface). Furthermore, the angular nonuniformity of measurement sensitivity refers to the fact that the measurement sensitivity differs for each light emitted in different directions from the same position on the surface to be measured of the light source to be measured. Therefore, when measuring color, in order to reduce measurement errors due to differences in the measurement position and measurement angle, the position of measurement sensitivity is It is necessary to reduce unevenness and angle unevenness.

In the above-mentioned Patent Document 1, the measurement light is guided using a light guide made by bundling a large number of fibers, but in order to reduce unevenness in light intensity and measurement errors, each fiber is randomly connected. It requires braiding, which is expensive. Furthermore, since it is difficult to control the filling condition, bending condition, stress condition, etc. of the fibers, it is difficult to design a light guide that is less susceptible to the effects of positional and angular unevenness in the emission intensity of the light source to be measured. As a result, it becomes difficult to reduce positional and angular variations in measurement sensitivity.

The present invention has been made in order to solve the above problems, and its purpose is to provide a configuration using an inexpensive light guiding member, which is less susceptible to the effects of positional and angular unevenness in the emission intensity of the light source to be measured. The object of the present invention is to provide a photometric device that can reduce positional and angular variations in measurement sensitivity.

A photometric device according to one aspect of the present invention includes a light guide member in the form of a polygonal prism or a truncated polygonal pyramid, whose end face on the light incidence side and the end face on the light output side are polygonal, and an image of the light source to be measured is transmitted to the light guide member. an objective optical system formed on the light-incidence side end face; and a light receiving unit that receives light that enters the light guide member from the light source to be measured through the objective optical system and exits from the light-emission side end face of the light guide member. and a light receiving section, the light receiving section having a plurality of sensors having different characteristics and disposed immediately after the light exit side end surface of the light guide member, or the light receiving section having a plurality of sensors having different characteristics, A relay optical system is disposed between the light-emitting side end surface of the light guide member and the light-emitting side end surface of the light guide member so that the end surface and the light-receiving surface of the light-receiving section are conjugate.

In the configuration in which the light emitted from the light source to be measured is guided to the light receiving section via the objective optical system and the light guide member (and the relay optical system as necessary), the light guide member is a simple polygonal prism or polygonal pyramid. Because it has a table shape, it has a simpler structure and is cheaper than a conventional light guide that guides light by randomly weaving multiple fibers. In addition, the light from the light source to be measured that enters the light guide member in the shape of a polygonal prism or truncated polygonal pyramid is incident on the sides of the light guide member (the light incident side end face and the light output The light is totally reflected by surfaces other than the side end surfaces), is guided, and enters the light receiving section. Therefore, each sensor in the light receiving section receives a mixture of light emitted from various positions on the surface to be measured of the light source to be measured and light emitted from the surface to be measured at various angles. . As a result, even if there are positional and angular irregularities in the emission intensity (emission luminance) of the light source to be measured on the surface to be measured, the light receiving section can be made less susceptible to the effects, and this makes it possible to reduce the influence of positional and angular variations in the measurement sensitivity. It is also possible to reduce angular irregularities.

1 is an explanatory diagram showing a schematic configuration of a photometric device according to an embodiment and Example 1 of the present invention; FIG. FIG. 2 is a perspective view showing an example of the configuration of a light guide member of the photometric device. It is a perspective view which shows the other example of a structure of the said light guide member. It is a perspective view showing still another example of composition of the above-mentioned light guide member. It is a perspective view showing still another example of composition of the above-mentioned light guide member. FIG. 3 is a plan view schematically showing the light incident side end face of the light guide member in FIG. 2A when viewed from the measurement range regulating aperture side. FIG. 3 is a plan view showing the configuration of a light receiving section of the photometric device. FIG. 3 is a cross-sectional view showing the configuration of the light receiving section. FIG. 3 is an explanatory diagram schematically showing the optical path of a light beam guided inside the light guide member. 2D is an explanatory diagram showing an expanded optical path of a light beam guided inside the light guide member of FIG. 2D. FIG. FIG. 3 is a plan view schematically showing the light incident side end face of the light guide member in FIG. 2B when viewed from the measurement range regulating aperture side. FIG. 3 is a plan view schematically showing the planar shape of a light receiving section when the light guide member of FIG. 2B is used. FIG. 2C is a plan view schematically showing the light incident side end face of the light guide member in FIG. 2C when viewed from the measurement range regulating aperture side. FIG. 2C is a plan view schematically showing the planar shape of the light receiving section when the light guide member of FIG. 2C is used. FIG. 2 is an explanatory diagram schematically showing the general configuration of a photometric device according to a second embodiment. FIG. 7 is an explanatory diagram schematically showing the general configuration of a photometric device of Example 3. FIG. 7 is an explanatory diagram schematically showing the general configuration of a photometric device of Example 4. FIG. 7 is an explanatory diagram schematically showing the general configuration of a photometric device of Example 5. FIG. 7 is an explanatory diagram schematically showing the general configuration of a photometric device of Example 6. FIG. 7 is an explanatory diagram schematically showing the general configuration of a photometric device of Example 7. FIG. 7 is an explanatory diagram schematically showing the general configuration of a photometric device of Example 8. FIG. 7 is an explanatory diagram schematically showing the general configuration of a photometric device of Example 9. FIG. 2 is an explanatory diagram schematically showing the general configuration of a photometric device of Comparative Example 1. FIG. FIG. 2 is an explanatory diagram schematically showing an example of simulation results of spatial distribution and angular distribution of measurement sensitivity. FIG. 2 is an explanatory diagram schematically showing a coordinate system of a light source to be measured. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor A', which is one of the four sensors of Comparative Example 1. FIG. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor B', which is one of the four sensors of Comparative Example 1. FIG. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor C', which is one of the four sensors of Comparative Example 1. FIG. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor D', which is one of the four sensors of Comparative Example 1. FIG. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor A, which is one of the four sensors of Example 1. FIG. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor B, which is one of the four sensors of Example 1. FIG. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor C, which is one of the four sensors of Example 1. FIG. 3 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in sensor D, which is one of the four sensors of Example 1. FIG. FIG. 7 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 2; FIG. 7 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 3; FIG. 7 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 4. 12 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 5. FIG. FIG. 7 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 6. FIG. 7 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 7; FIG. 12 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 8. 12 is an explanatory diagram showing the results of simulating the spatial distribution and angular distribution of measurement sensitivity in an arbitrary sensor of Example 9. FIG.

An embodiment of the present invention will be described below based on the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a photometric device 1 of this embodiment (Example 1). The photometric device 1 includes a light guiding member 2, an objective optical system 3, a relay optical system 4, and a light receiving section 5. In the configuration of the photometer 1 described above, the light emitted from the surface to be measured _LS0 of the light source LS to be measured is guided to the light guide member 2 via the objective optical system 3, and the light is guided inside the light guide member 2. Thereafter, the light is guided to the light receiving section 5 via the relay optical system 4. Each member constituting the photometric device 1 will be explained below.

(Light guide member)
FIG. 2A is a perspective view showing an example of the configuration of the light guide member 2. FIG. The light guide member 2 is an optical element that has a light incident side end surface 2a and a light output side end surface 2b, and guides the light incident inside from the light incident side end surface 2a and outputs it from the light output side end surface 2b. In this embodiment, it is comprised of a solid (filled) rod made of glass. In the present embodiment, the light guide member 2 has a quadrangular prism shape in which the light incident side end surface 2a and the light exit side end surface 2b are quadrilaterals (for example, squares) of the same size, but the shape is not limited to this. do not have.

FIG. 2B is a perspective view showing another example of the structure of the light guide member 2. Moreover, FIG. 2C is a perspective view showing still another example of the structure of the light guide member 2. As shown in these figures, the light guide member 2 has a triangular prism shape in which the light incident side end surface 2a and the light output side end surface 2b are triangles of the same size (e.g., an equilateral triangle), or the light incident side end surface 2a and the light The output side end surface 2b may be in the shape of a hexagonal prism, which is a hexagon (for example, a regular hexagon) of the same size. That is, the light guide member 2 may have a polygonal prism shape in which the light incident side end surface 2a and the light exit side end surface 2b are polygons of the same size.

Moreover, FIG. 2D is a perspective view showing still another example of the structure of the light guide member 2. As shown in the figure, the light guide member 2 may have a truncated quadrangular pyramid shape in which the light incident side end surface 2a and the light exit side end surface 2b are squares of different sizes. Other shapes, although not shown, include a truncated triangular pyramid shape in which the light input side end surface 2a and the light output side end surface 2b are triangles of different sizes, and a hexagonal shape in which the light input side end surface 2a and the light output side end surface 2b are different sizes. It may be in the shape of a hexagonal truncated pyramid. In other words, the light guide member 2 may have the shape of a truncated polygonal pyramid in which the light incident side end surface 2a and the light exit side end surface 2b are polygons of different sizes.

Since the light guide member 2 has the above-described polygonal prism or truncated polygonal pyramid shape, the light that enters the inside of the light guide member 2 via the light incident side end surface 2a has an angle of incidence with respect to the light incident side end surface 2a. The light is totally reflected and guided by the side surface 2c of the light guide member 2 (the interface with the air in the light guide member 2) a number of times, and is emitted from the light output side end surface 2b. Note that the side surface 2c is a surface that connects the light input side end surface 2a and the light output side end surface 2b, and is provided in the same number as the vertices (or sides) of the polygon forming the light input side end surface 2a and the light output side end surface 2b. It will be done.

Note that, for example, for light incident at an angle perpendicular to or close to the center of the light-incidence end surface 2a (the intersection of the light-incidence end surface 2a and the optical axis of the objective optical system 3), the light enters the inside of the light guide member 2. After entering through the incident side end surface 2a, the light is guided without being totally reflected on the side surface 2c and is emitted from the light output side end surface 2b. Therefore, the above-mentioned "number of times depending on the angle of incidence" includes zero times.

Note that the light guide member 2 may be formed of, for example, a hollow pipe (light pipe) having a polygonal cross section. In this case, by forming a reflective film made of metal on the inner surface of the pipe, the light incident on the light guide member 2 can be reflected by the inner surface (reflective film) and guided. Further, 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 and forms an image of the light source LS to be measured on the light incident side end surface 2a of the light guide member 2. The objective optical system 3 includes a front lens system 31 located on the side of the light source to be measured LS, a rear lens system 32 located on the side of the light guide member 2, and a spread of light emitted from one point of the light source LS to be measured. It is configured with an aperture AP1 (measurement angle regulating aperture) that regulates the angle, and an aperture AP2 (measurement range regulating aperture, field aperture) that regulates the measurement range of the light source LS to be measured.

Due to the arrangement of the objective lens system 3, the measured surface _LS0 of the measured light source LS and the light incident side end surface 2a of the light guide member 2 have a conjugate relationship. That is, light emitted from a certain point on the surface to be measured LS ₀ of the light source LS to be measured is focused on a certain point on the light incident side end surface 2 a of the light guide member 2 . In this embodiment, the front lens system 31 is composed of two lenses, and the rear lens system 32 is composed of three lenses, but any configuration that can realize the above conjugate relationship may be used. The number of lenses in the front lens system 31 and the rear lens system 32 is not particularly limited.

The aperture AP1 is arranged at the rear focal position of the front lens system 31. Each point in the plane of the aperture AP1 (aperture) corresponds to the light emission angle at the measured surface _LS0 of the measured light source LS. By arranging the aperture AP1, it is possible to appropriately regulate the measurement angle (output angle) of the light emitted from the surface to be measured _LS0 without excess or deficiency, and to measure only the light within the angular range desired to be measured. In addition, in this embodiment, the shape of the opening of the aperture AP1 is circular, but it may be rectangular or may have another shape.

The aperture AP2 is arranged immediately in front of the light incident side end surface 2a of the light guide member 2. Each point within the plane of the aperture AP2 (aperture) corresponds to each point on the measured surface _LS0 of the measured light source LS. By arranging the aperture AP2, it is possible to appropriately regulate the measurement range (measurement area) of the light source LS to be measured without excess or deficiency, and to measure only the light in the range to be measured.

FIG. 3 schematically shows the light incident side end surface 2a of the light guide member 2 in FIG. 2A when viewed from the aperture AP2 side. In this embodiment, the aperture 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 surface 2a of the light guide member 2. Note that the opening AP2a of the aperture AP2 may be rectangular or may have another shape. Furthermore, it is also possible to omit the arrangement of the aperture AP2. In this case, the measurement range of the surface to be measured LS ₀ of the light source LS to be measured becomes similar to the shape of the light incident side end surface 2 a of the light guide member 2 .

(Relay optical system)
The relay optical system 4 transmits the light emitted from the light output side end surface 2b of the light guide member 2 to the light receiving section so that the light output side end surface 2b of the light guide member 2 and the light receiving surface 5a of the light receiving section 5 are conjugate. This is an optical system that leads to 5. That is, due to the arrangement of the relay optical system 4, the light emitted from a certain point on the light-emitting side end surface 2b of the light guide member 2 is focused on a certain point on the light-receiving surface 5a of the light-receiving section 5, and An image of the light-emitting side end surface 2b is enlarged and formed on the light-receiving surface 5a of the light-receiving section 5. In this embodiment, the relay optical system 4 is composed of four lenses, but the number of lenses in the relay optical system 4 is not particularly limited as long as it can realize the above conjugate relationship.

(Light receiving section)
The light receiving section 5 receives light that enters the light guide member 2 from the light source LS to be measured via the objective optical system 3 and is emitted from the light output side end surface 2b of the light guide member 2. This light receiving section 5 is composed of a plurality of sensors 51 having different characteristics. In this embodiment, the plurality of sensors 51 of the light receiving section 5 each have a measurement sensitivity corresponding to the color matching functions X, Y, and Z. The configuration of the light receiving section 5 will be explained in more detail below.

4 is a plan view showing the configuration of the light receiving section 5, and FIG. 5 is a sectional view showing the structure of the light receiving section 5. As shown in FIG. The light receiving section 5 has four sensors 51 (51a to 51d). Each sensor 51 includes a light receiving element 52 and an optical filter 53. Each light-receiving element 52 is composed of, for example, a silicon photodiode, and outputs an electric signal corresponding to the amount of light received to a subsequent electric circuit (not shown). The light-receiving surface 5a of each light-receiving element 52 is square or rectangular, and is located at each of the four corners of one quadrangle. From this, it can be said that the plurality of sensors 51 of the light receiving section 5 have rectangular light receiving surfaces 5a located at the four corners of one rectangle, respectively. Note that each light-receiving surface 5a may be a polygon other than a quadrangle (for example, a triangle), or may be circular.

The optical filter 53 of each sensor 51 has an optical property of transmitting light in a predetermined wavelength range, is formed in a larger size than the light receiving element 52, and is arranged on the light incident side of the light receiving element 52. . In this embodiment, the optical filters 53 of three of the four sensors 51 (for example, sensors 51a to 51c) are optical filters that transmit light in wavelength ranges corresponding to the color matching functions X, Y, and Z. It is composed of filters 53X, 53Y, and 53Z. As a result, the three sensors 51 have measurement sensitivities corresponding to the color matching functions X, Y, and Z, respectively. The light transmitted through the optical filters 53X, 53Y, and 53Z of the three sensors 51 is received by the corresponding light receiving element 52. Color and brightness can be measured by processing electrical signals output from each light receiving element 52 using an electrical circuit.

That is, since the plurality of sensors 51 of the light receiving section 5 each have a measurement sensitivity corresponding to the color matching functions X, Y, and Z, the electric signal output from each sensor 51 (each light receiving element 52) (corresponding to the tristimulus values of It becomes possible to ask for it. This makes it possible to realize a colorimeter (colorimeter) that measures color and brightness.

Further, the optical filter 53 of the remaining sensor 51 (for example, the sensor 51d) among the four sensors 51 described above is constituted by an optical filter 53Y that transmits light in a wavelength range 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, an electric circuit for flicker detection. This makes it possible to detect flicker based on the electrical signal output from the light receiving element 52.

Note that one of the two optical filters 53Y may be configured with, for example, an optical filter that transmits infrared rays. In this case, since four types of optical filters 53 are arranged, four types of optical characteristics can be measured simultaneously.

In this embodiment, the optical characteristics of the three optical filters 53X, 53Y, and 53Z among the four optical filters 53 are different from each other, but it is sufficient that the characteristics of at least two optical filters 53 are different from each other ( It is sufficient that all the optical filters 53 do not have the same characteristics). Each of the plurality of sensors 51 of the light receiving section 5 includes a light receiving element 52 whose light receiving surface 5a is square or rectangular, and an optical filter 53 disposed on the light incident side of the light receiving element 52, and at least two of the optical filters 53 are arranged on the light incident side of the light receiving element 52. Since the two characteristics are different from each other, it becomes possible to easily arrange sensors 51 having a plurality of characteristics together, as shown in FIG.

Each sensor 51 is housed in the recess 54a of the holding member 54 such that the optical filter 53 is located on the light incident side of the light receiving element 52, and the light receiving element 52 and the optical filter 53 are arranged with a gap between them. is retained. The recess 54a has a step-like shape in which the aperture diameter gradually narrows from the side where the optical filter 53 is arranged to the side where the light receiving element 52 is arranged. It can be accommodated in the recess 54a so that it becomes.

The holding member 54 described above also serves as a light shielding wall that partitions the sensors 51 located adjacent to each other. In other words, since the holding member 54 exists as a light shielding wall between two adjacent sensors 51, the light that has passed through the optical filter 53 of one adjacent sensor 51 enters the light receiving element 52 of the other adjacent sensor 51. This makes it possible to reduce measurement errors.

Further, in the configuration in which a plurality of sensors 51 (optical filter 53 and light receiving element 52) are arranged and held by the holding member 54 as in this embodiment, the arrangement area of the plurality of sensors 51 is expanded. However, since the image of the light-emitting end surface 2b of the light guide member 2 is enlarged and formed on the light-receiving surface 5a by the relay optical system 4, even if a plurality of sensors 51 are held by the holding member 54, each It becomes possible to secure a sufficiently wide illumination range for the sensor 51.

Further, 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 section 5 is the light receiving range of each of the plurality of sensors 51 of the light receiving section 5. In other words, all the light receiving surfaces 5a of each light receiving element 52 are included. As a result, errors in assembling the optical system (discrepancies in the position and inclination of each component) and changes in the optical system due to environmental changes (temperature changes, humidity changes, vibrations, shocks, etc.) Even if the position of the irradiation range R (the imaging range of the image of the light-emitting end surface 2b of the light guide member 2) shifts, the change in the amount of received light (measured value) becomes small, so stable measurement is possible.

In particular, in this embodiment, the light incident side end surface 2a and the light exit side end surface 2b of the light guide member 2 are square (see FIG. 2A), and the plurality of sensors 51 of the light receiving section 5 are arranged at the four corners of one square. Each has a rectangular light-receiving surface 5a located thereon. Thereby, the light emitted from the light-emitting side end surface 2b of the light guide member 2 can be efficiently guided to the required range (each light-receiving surface 5a) of the light-receiving section 5. Therefore, since the light utilization efficiency increases (because most of the illumination light can be received), measurement with a high S/N (Signal-to-Noise) ratio becomes possible.

Further, as the optical filter 53 described above, it is possible to use an interference film filter in which an interference film is formed on a glass substrate. When an interference film filter is used, the spectral transmittance changes depending on the incident angle of the light beam to the interference film, but in this embodiment, the relay optical system 4 allows the image of the light-emitting side end surface 2b of the light guide member 2 to be adjusted to the light-receiving surface. By forming an enlarged image on 5a, the angle of incidence of the light beam on each sensor 51 becomes smaller. This makes it possible to reduce changes in spectral transmittance due to the angle of incidence of light in the interference film filter.

Note that as the optical filter 53, it is also possible to use a colored glass filter that absorbs light in a specific wavelength range, an ND (neutral density) filter that attenuates light in a wide wavelength range, a linear polarizer, a wavelength plate, etc. . Further, a plurality of optical filters 53 may be arranged on the light incident side of one light receiving element 52.

Note that all the optical filters 53 may be composed of the same filter. However, in this case, in order to make the characteristics of the plurality of sensors 51 different, it is necessary to use different sensors as the light receiving elements 52. For example, by using a combination of a silicon photodiode for visible light and an InGaAs photodiode for infrared light, or by using a combination of a light-receiving element capable of high-sensitivity measurement and a light-receiving element capable of high-speed measurement. , it becomes possible to simultaneously measure various optical characteristics while using the same optical filter 53.

Note that the number of sensors 51 constituting the light receiving section 5 is not limited to four in this embodiment. For example, by using more sensors 51 and arranging them appropriately, such as using 9 sensors 51 and arranging them in 3 rows and 3 columns, or using 16 sensors 51 and arranging them in 4 rows and 4 columns, more optical It is also possible to measure properties simultaneously.

(Regarding the effect of reducing positional and angular variations in measurement sensitivity due to the light guiding member)
Next, the effect of reducing positional and angular variations in measurement sensitivity by using the light guide member 2 of this embodiment will be described.

In the configuration using the light guide member 2 in the shape of a polygonal prism or a truncated polygonal pyramid as in this embodiment, as described above, the light emitted from the light source to be measured LS and incident on the inside of the light guide member 2 is , total reflection is repeated on the side surface 2c of the light guide member 2 a number of times corresponding to the incident angle on the light incident side end surface 2a, and the light is emitted from the light output side end surface 2b. In this configuration, considering one point on the light-emitting end surface 2b, that one point is illuminated by light from various points on the light-incoming end surface 2a of the light guide member 2. Furthermore, the surface to be measured LS ₀ of the light source LS to be measured and the light incident side end surface 2 a of the light guide member 2 are conjugated by the objective optical system 3 , and the light output side end surface 2 b of the light guide member 2 and the light receiving part 5 are conjugated. Since the surface 5a is conjugate with the relay optical system 4, light from various points of the light source LS to be measured will eventually illuminate each sensor 51 of the light receiving section 5 via the light guide member 2. . That is, even if there is a positional unevenness in the emission intensity (brightness) of the measured light source LS on the measured surface LS ₀ , each sensor 51 can detect that the light from various positions on the measured surface LS ₀ is mixed by the light guide member 2 . By receiving the reflected light, it becomes less susceptible to the influence of positional unevenness on the surface to be measured LS ₀ . Thereby, in each sensor 51, positional unevenness in measurement sensitivity can be reduced, and stable measurement is possible.

In addition, in a configuration using the light guide member 2 in the shape of a polygonal prism or a truncated polygonal pyramid, the light that is emitted from the light source LS to be measured is incident on the light incident side end surface 2a of the light guide member 2 depending on the emission angle. The angle changes. The light that enters the inside of the light guide member 2 via the light incident side end face 2a is totally reflected on the side face 2c of the light guide member 2 a number of times corresponding to the angle, and is reflected at various positions on the light output side end face 2b. (a position corresponding to the angle of incidence on the light guide member 2). Therefore, similarly to the above, if we consider one point on the light-emitting end surface 2b, the one point will be illuminated with light from various angles. The emission angle of the light from the light source LS to be measured corresponds to the incident angle of the light at the light-incidence side end surface 2a of the light guide member 2, and the light-emission side end surface 2b of the light guide member 2 and the light-receiving surface of the light-receiving section 5. 5a is conjugate, the light emitted from the light source LS to be measured at various angles will eventually illuminate each sensor 51 of the light receiving section 5 via the light guide member 2. In other words, even if there is angular unevenness in the emission intensity (luminance) of the surface to be measured LS ₀ of the light source LS to be measured, each sensor 51 allows the light emitted from the surface to be measured LS ₀ at various angles to reach the light guide member 2. By receiving the mixed light, it becomes less susceptible to the influence of angular unevenness on the surface to be measured LS ₀ . Thereby, in each sensor 51, angular unevenness in measurement sensitivity can be reduced, allowing stable measurement.

Furthermore, since the light guide member 2 has a simple polygonal prism or truncated polygonal pyramid shape (see FIGS. 2A to 2D), it is more difficult to use than conventional light guides that guide light by randomly weaving multiple fibers. , the configuration is simple, and the cost is low. Therefore, with a simple configuration using the inexpensive light guide member 2, it is possible to obtain the effect of reducing positional and angular variations in measurement sensitivity. In particular, in this embodiment, as described above, since the light receiving section 5 has a plurality of sensors 51 with different characteristics, color and brightness can be measured. The above-mentioned effects can be obtained in a color luminance meter that performs the following.

Further, FIG. 6 is an explanatory diagram schematically showing the optical path of the light beam guided inside the light guide member 2. As shown in FIG. The objective optical system 3 (see FIG. 1) reduces and forms the image of the surface to be measured _LS0 of the light source LS to be measured on the light incident side end surface 2a of the light guide member 2. This makes it possible to use a light guide member in which the diameter D ₁ of the inscribed circle of the entrance side end surface 2a and the diameter D ₂ of the inscribed circle of the light output side end surface 2b are small, and the light emitted from the light source LS to be measured is The incident angle θ of the light at the light incident side end surface 2a of the light guide member 2 becomes larger than the output angle of the light guide member 2 (therefore, the refraction angle θ _P inside the light guide member 2 also becomes larger). From FIG. 6, it can be seen that the larger the incident angle θ of the light at the light incident side end surface 2a (the larger the refraction angle θ _P ), or the smaller the diameters D ₁ and D ₂ , the more light that has entered the inside of the light guide member 2. It can be seen that the number of reflections on the side surface 2c increases.

In this embodiment, D ₁ =D ₂ , and among the light rays emitted from the light source to be measured LS and incident on the light incident side end surface 2a of the light guide member 2, the angle θ formed with the optical axis AX is the maximum. The approximate number of times the light beam LT is reflected by the side surface 2c of the light guide member 2 is:
(Ltanθ _P )/D ₁ or (Ltanθ _P )/D ₂
It is expressed as However, when n _P is the refractive index of the light guide member 2, the refraction angle θ _P is an angle that satisfies n _P sin θ _P =sin θ. The optical axis AX is an axis that connects the center of the inscribed circle of the light incident side end surface 2a of the light guide member 2 and the center of the inscribed circle of the light exit side end surface 2b, and is and coaxial with the optical axis of the relay optical system 4.

As described above, in the configuration of the present embodiment, when considering one point on the light-emitting side end surface 2a of the light guide member 2, the one point is the light emitted from the light source LS to be measured at various angles. Therefore, the influence of angular unevenness of the light source LS to be measured can be reduced. When the light beam is reflected inside the light guide member 2, the angle of the light beam is reversed, so as the number of reflections of the light beam increases, the above-mentioned one point will be illuminated with light from more various angles. Therefore, it is possible to more effectively reduce the influence of the angular unevenness of the light source LS to be measured, thereby reducing the angular unevenness of the measurement sensitivity, and more stable measurement is possible.

Furthermore, when the number of reflections on the light guide member 2 is constant, the larger the refraction angle θ _P and the smaller D ₁ or D ₂ , the smaller the length L of the light guide member 2 in the optical axis AX direction. can. In this case, the photometric device 1 can be made smaller.

(About the number of reflections when using a truncated polygonal pyramidal light guide member)
FIG. 7 shows an expanded view of the optical path of the light beam guided inside the light guide member 2 when the light guide member 2 having the shape of a truncated polygonal pyramid shown in FIG. 2D is used as the light guide member 2. It is an explanatory diagram. In the light guide member 2 described above, the light incident side end surface 2a and the light exit side end surface 2b have a square shape, but the area of the light exit side end surface 2b is larger than the area of the light incident side end surface 2a. When using such a truncated polygonal pyramidal light guide member 2, even if the light receiving section 5 is placed immediately after the light output side end surface 2b of the light guide member 2 (without intervening the relay optical system 4), The light emitted from the light emitting side end surface 2b of the light guiding member 2 can be guided to the entire light receiving section 5. In this way, by arranging the light receiving section 5 immediately after the light emitting end surface 2b of the light guide member 2 and omitting the arrangement of the relay optical system 4, it is possible to realize an inexpensive photometric device 1. .

Here, when using the light guide member 2 having the shape of a truncated polygonal pyramid, the number of reflections of the light guided inside can be considered as follows. That is, when using the light guide member 2 having a truncated polygonal pyramid shape, the angle θ with the optical axis AX of the light rays emitted from the light source LS to be measured and incident on the light incident side end surface 2a of the light guide member 2 is The approximate number of times the maximum light ray LT is reflected by the side surface 2c of the light guide member 2 is expressed as α/β. However, in FIG. 7, α is the angle (°) between the straight line connecting points A and O and the optical axis AX, and β is the side surface 2c of the light guide member 2 in the cross section including the optical axis AX. The angle (°) is twice the angle formed by the optical axis AX and the optical axis AX. Here, point O refers to the point where the side surface 2c of the light guide member 2 intersects with the optical axis AX when the side surface 2c of the light guide member 2 is extended in the cross section including the optical axis AX, and the point A is the point where the light ray LT enters the light guide member 2. The ray after being refracted at the side end surface 2a (the angle with the optical axis AX is θ)_P) with a straight line (dashed line LP) whose center is point O and radius L₀This is the point where the circles intersect. Specifically, α and β are angles that satisfy the following relational expression. That is,
L₀sin α={L−L₀(1-cosα)}tanθ_P
tan(β/2)=(D₂-D₁)/2L
L₀=D₂L/(D₂-D₁)
n_Psin θ_P= sin θ
and
L : Length of light guide member 2 in optical axis AX direction (mm)
θ : Maximum value (°) of the angle between the light ray that enters the center of the light incident side end surface 2a of the light guide member 2 and the normal line of the light incident side end surface 2a.
D₁: Diameter of the inscribed circle of the light incident side end surface 2a of the light guide member 2 (mm)
D₂: Diameter of the inscribed circle of the light-emitting side end surface 2b of the light guide member 2 (mm)
n_P: refractive index of light guide member 2
It is.

If α/β>1, that is, if the number of reflections of the light beam LT on the side surface 2c of the light guide member 2 is at least one time, by reflecting the light beam LT on the side surface 2c, various variations of the surface to be measured _LS0 can be achieved. The light guide member 2 can mix the light emitted from a certain position and the light emitted from the measurement surface LS ₀ at various angles. Therefore, it is possible to reduce the influence of the positional unevenness and angular unevenness of the light source LS to be measured, and to reduce the positional unevenness and angular unevenness of the measurement sensitivity. In particular, α/β>2 allows the light beam LT to be reflected multiple times on the side surface 2c, thereby reliably reducing the influence of positional and angular unevenness of the light source LS to be measured, and reducing the positional and angular unevenness of measurement sensitivity. This is desirable because it can reliably reduce In addition, from the viewpoint of obtaining the effects of this embodiment more reliably, from the results of the examples described later, it is more desirable that α/β>4, it is even more desirable that α/β>7, and It is further desirable that β>10.

In addition, in the case of α≪1, β≪1,
α≒(L/L ₀ ) tanθ _P = {(D ₂ - D ₁ )/D ₂ }/tanθ _P
β≒(D ₂ - D ₁ )/L
Then,
α/β≒(Ltanθ _P )/D ₂
becomes. That is, in this case, α/β roughly matches the number of reflections in the case of D ₁ =D ₂ described above.

(Relationship between other shapes of the light guiding member and the light receiving part)
FIG. 8 schematically shows a state in which the light incident side end surface 2a is viewed from the aperture AP2 side when the triangular prism-shaped light guide member 2 shown in FIG. 2B is used. As shown in the figure, even when the triangular prism-shaped light guide member 2 is used, the size of the circular opening AP2a of the aperture AP2 is slightly smaller than the inscribed circle of the light incident side end surface 2a of the light guide member 2. It only needs to be set.

FIG. 9 schematically shows the planar shape of the light receiving section 5 when the light guide member 2 of FIG. 2B is used. The light receiving section 5 is composed of three circular sensors 51 (51a to 51c) in plan view, and each sensor 51 may be arranged to correspond to each vertex of one equilateral triangle. Since the light emitting side end surface 2b of the light guide member 2 has an equilateral triangular shape, 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 section 5 also extends to the light receiving section. It has an equilateral triangular shape that includes all the light receiving ranges of the three sensors 51 of No. 5.

FIG. 10 schematically shows a state in which the light incident side end surface 2a is viewed from the aperture AP2 side when the hexagonal columnar light guide member 2 shown in FIG. 2C is used. As shown in the figure, even when a hexagonal columnar light guide member 2 is used, the size of the circular opening AP2a of the aperture AP2 is slightly smaller than the inscribed circle of the light incident side end surface 2a of the light guide member 2. It only needs to be set.

FIG. 11 schematically shows the planar shape of the light receiving section 5 when the light guide member 2 of FIG. 2C is used. The light receiving unit 5 is composed of seven sensors 51 (51a to 51g) that are square or rectangular in plan view, and each sensor 51 is arranged so as to correspond to each vertex and center of one regular hexagon. You can. Since the shape of the light emitting side end surface 2b of the light guide member 2 is a regular hexagon, 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 section 5 is also the same as the light receiving section. It has a regular hexagonal shape that includes all the light receiving ranges of the seven sensors 51 of No. 5.

(Example)
Next, specific examples of the present invention will be described as Examples 1 to 9. Further, for comparison with each example, a comparative example will also be described. Note that Example 9 is merely a reference example of the present invention and does not fall within the scope of the present invention.

FIGS. 12 to 19 schematically show the general configuration of the photometric device 1 of Examples 2 to 9, respectively. Further, FIG. 20 schematically shows the general configuration of the photometric device 1' of Comparative Example 1. Note that the configuration of the photometric device 1 of Example 1 is as shown in FIG. 1. Note that in FIGS. 1 and 12 to 20, the scales of each photometric device are adjusted for convenience (the scales are not the same).

The photometric device 1 of the second embodiment has the same configuration as the photometric device 1 of the first embodiment, except that the exit pupil position is shifted toward the light source to be measured LS compared to the photometric device 1 of the first embodiment. It is. Here, the position of the exit pupil refers to the position of the image formed by the aperture AP1.

The photometric device 1 of the third embodiment has the same configuration as the photometric device 1 of the second embodiment, except that the position of the exit pupil is shifted toward the light source to be measured LS compared to the photometric device 1 of the second embodiment. It is. The photometric device 1 of Example 4 has the same configuration as the photometric device 1 of Example 1, except that the position of the exit pupil is shifted toward the light receiving section 5 side compared to the photometric device 1 of Example 1. be.

In the photometric device 1 of the fifth embodiment, the length of the light guide member 2 in the optical axis direction is increased compared to the photometer 1 of the first embodiment, and the length of the light beam incident on the inside of the light guide member 2 at the side surface 2c is increased. The configuration is the same as that of the photometric device 1 of Example 1 except that the number of reflections (α/β) is increased.

In the photometric device 1 of Example 6, the quadrangular prism-shaped light guide member 2 of the photometric device 1 of Example 1 is replaced with a truncated quadrangular pyramid light guide member 2 (see FIG. 2D), and the relay optical system 4 is not disposed. The structure is the same as that of the photometric device 1 of Example 1, except that the light receiving section 5 is disposed immediately after the light emitting end surface 2b of the light guide member 2.

The photometric device 1 of Example 7 replaces the quadrangular prism-shaped light guide member 2 of the photometric device 1 of Example 1 with a triangular prism-shaped light guide member 2 (see FIG. 2B), and has four quadrangular sensors 51. The configuration is the same as that of the photometric device 1 of Example 1, except that the light receiving section 5 (see FIG. 9) having three circular sensors 51 is used instead of the light receiving section 5. The photometric device 1 of Example 8 replaces the quadrangular prism-shaped light guide member 2 of the photometric device 1 of Example 1 with a hexagonal prism-shaped light guide member 2 (see FIG. 2C), and has four quadrangular sensors 51. The configuration is the same as that of the photometric device 1 of Example 1, except that the light receiving section 5 (see FIG. 11) having seven rectangular sensors 51 is used instead of the light receiving section 5.

The photometric device 1 of Example 9 has a shorter length of the light guiding member 2 in the optical axis direction than that of the photometric device 1 of Example 1, and the length of the light beam entering the inside of the light guiding member 2 on the side surface 2c is reduced. The configuration is the same as that of the photometric device 1 of Example 1 except that the number of reflections (α/β) is reduced.

The photometric device 1' of Comparative Example 1 has the same configuration as the photometric device 1 of Example 1, except that the arrangement of the light guide member 2 is omitted.

Table 1 shows each parameter in Examples 1 to 9 and Comparative Example 1.

(evaluation)
In order to confirm the effects of the configurations of Examples 1 to 9 and Comparative Example 1, the spatial distribution and angular distribution of measurement sensitivity in at least one sensor 51 of the light receiving section 5 were simulated. In the simulation of the spatial distribution and angular distribution of measurement sensitivity, when the surface to be measured LS ₀ of the light source LS to be measured is a uniform and completely diffuse surface light source, the light emitted from each position of the surface to be measured LS ₀ is calculated as follows. Optical software is used to simulate how much light reaches the light receiving element and how much light emitted in each direction from the surface to be measured LS ₀ reaches the light receiving element. For example, FIG. 21 schematically shows an example of simulation results of the spatial distribution and angular distribution of measurement sensitivity in one sensor 51. In these distributions, white parts represent relatively high measurement sensitivity, and black parts represent relatively low measurement sensitivity.

Further, FIG. 22 schematically shows the coordinate system of the light source LS to be measured (surface to be measured LS ₀ ). The horizontal (x direction) and vertical (y) positions of the spatial distribution of measurement sensitivity shown in FIG. ₂₁ are the horizontal (X) and vertical (Y direction). In _addition , the horizontal angle (θx) and vertical angle (θy) of the angular distribution of measurement sensitivity are the horizontal direction (X direction) angle ( θX) and an angle (θY) in the vertical direction (Y direction), respectively.

23 to 26 show simulations of the spatial distribution and angular distribution of measurement sensitivity in the four sensors 51 (herein referred to as sensor A', sensor B', sensor C', and sensor D') of Comparative Example 1. Showing results. Note that the sensor A', sensor B', sensor C', and sensor D' correspond to the sensor 51a, sensor 51b, sensor 51c, and sensor 51d in FIG. 4, respectively. From these figures, it can be seen that in Comparative Example 1, the spatial distribution of measurement sensitivity is extremely non-uniform between sensors A' to D'.

In contrast, FIGS. 27 to 30 show the spatial distribution and measurement sensitivity of the four sensors 51 (herein referred to as sensor A, sensor B, sensor C, and sensor D) of the light receiving section 5 of the first embodiment. It shows the results of simulating the angular distribution. Note that the above-mentioned sensor A, sensor B, sensor C, and sensor D correspond to the sensor 51a, sensor 51b, sensor 51c, and sensor 51d in FIG. 4, respectively. From these figures, it can be seen that a similar spatial distribution of measurement sensitivity is obtained between sensors A to D, and a similar distribution is obtained for the angular distribution of measurement sensitivity. . Therefore, it can be seen that in Example 1, the spatial distribution and angular distribution of measurement sensitivity can be made uniform at the same time among a plurality of sensors.

Furthermore, FIGS. 31 to 38 show the spatial distribution and angular distribution of the measurement sensitivity of an arbitrary sensor (here, sensor A) among the plurality of sensors 51 constituting the light receiving section 5 of Examples 2 to 9. The results of the simulation are shown. Note that the above sensor A corresponds to the sensor 51a in FIG. 4 (Examples 2 to 6, 9), the sensor 51a in FIG. 9 (Example 7), or the sensor 51a in FIG. 11 (Example 8). . In Examples 2 to 9, as in Example 1, the spatial distribution of measurement sensitivity is approximately uniform within the measurement range. Due to the arrangement of the light guide member 2, each sensor 51 of Examples 1 to 9 receives the light amount averaged by the weight of the measurement sensitivity distribution, so that the light emission from the surface to be measured LS ₀ of the light source LS to be measured is Even if there is positional unevenness in intensity (luminance), the light receiving section 5 can reduce the influence of the positional unevenness and perform stable measurements.

Further, in Examples 1 to 9, the angular distribution of the measurement sensitivity varies to a degree depending on the embodiment, but all the embodiments have a sensitivity distribution over a wide range within the measurement range. Due to the arrangement of the light guide member 2, each sensor 51 of Examples 1 to 9 receives the light amount averaged by the weight of the measurement sensitivity distribution, so that the light emission from the surface to be measured LS ₀ of the light source LS to be measured is Even if there is angular unevenness in intensity (brightness), the light receiving section 5 can reduce the influence of the angular unevenness and perform stable measurements.

As can be seen from the simulation results of Examples 1 to 9 shown above, the spatial distribution and angular distribution of measurement sensitivity vary depending on the length L of the light guide member 2 and the exit pupil position. Therefore, by adjusting the length L of the light guide member 2 and the exit pupil position, it is possible to design the photometric device 1 having desired uniformity of measurement sensitivity.

〔others〕
The photometric device of this embodiment described above may be expressed as follows.

The photometric device of the present embodiment includes a light guide member in the form of a polygonal prism or a truncated polygonal pyramid, whose end face on the light incidence side and the end face on the light output side are polygonal, and an image of the light source to be measured is transferred to the light guide member at the light incidence side of the light guide member. an objective optical system formed on a side end surface; and a light receiving section that receives light that enters the light guide member from the light source to be measured via the objective optical system and is emitted from the light output side end surface of the light guide member. and 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 the light receiving section has a plurality of sensors having different characteristics, or A relay optical system is disposed between the light guide member and the light output side end surface of the light guide member so that the light receiving surface of the light receiver is conjugate with the light receiving surface of the light receiver.

In the above photometric device, the objective optical system includes a front lens system located on the side of the light source to be measured, a rear lens system located on the side of the light guide member, and a light source emitted from one point of the light source to be measured. A diaphragm that regulates a spread angle of light may be included, and the diaphragm may be disposed at a rear focal position of the front lens system.

The above photometric device is
α/β>2
It is desirable that you satisfy the following. however,
L₀sin α={L−L₀(1-cosα)}tanθ_P
tan(β/2)=(D₂-D₁)/2L
L₀=D₂L/(D₂-D₁)
n_Psinθ_P= sin θ
and
L : Length of the light guide member in the optical axis direction (mm)
θ : The maximum value (°) of the angle between the light ray incident on the center of the light-incidence side end face of the light guide member and the normal line of the light-incidence side end face.
D₁: Diameter (mm) of the inscribed circle of the light incident side end surface of the light guide member
D₂: Diameter (mm) of the inscribed circle of the light-emitting side end surface of the light guide member
n_P: refractive index of the light guide member
and D₁=D₂in the case of,
α/β=Ltanθ_p/D₂>2
It is.

In the above photometric device, each of the plurality of sensors of the light receiving section includes a light receiving element having a square or rectangular light receiving surface, and an optical filter disposed on a light incident side of the light receiving element, and the optical filter At least two of them may have different characteristics.

In the above photometric device, the irradiation range when the light emitted from the light emitting side end face of the light guide member irradiates the light receiving section includes all the light receiving ranges of the plurality of sensors of the light receiving section. You can.

In the above photometric device, each of the plurality of sensors of the light receiving section may have a measurement sensitivity corresponding to color matching functions X, Y, and Z.

In the above-mentioned photometric device, the light-incidence side end face and the light-output side end face of the light guide member are square, and the plurality of sensors of the light-receiving section are each arranged on a square light-receiving surface located at each of the four corners of one square. It may have.

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

INDUSTRIAL APPLICATION This invention can be utilized for a color luminance meter, for example.

1 Photometer 2 Light guide member 2a Light incident end face 2b Light exit end face 2c Side face 3 Objective optical system 4 Relay optical system 5 Light receiving section 5a Light receiving surface 31 Front lens system 32 Rear lens system 51 Sensor 52 Light receiving element 53 Optical filter AP1 Aperture LS Measured light source

Claims (7)

a polygonal prism or truncated polygonal pyramid light guide member whose light incident side end face and light exit side end face are polygonal;
an objective optical system that forms an image of the light source to be measured on the light incident side end surface of the light guide member;
a light receiving section that receives light that enters the light guide member from the light source to be measured via the objective optical system and is emitted from the light output 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 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 guiding member and the light receiving section. disposed via a relay optical system between the light-emitting side end surface of the light guide member so that the light-emitting surface is conjugate with the light-emitting surface;
α/β＞2
A photometric device that satisfies the following;
however,
L₀sin α={L−L₀(1-cosα)}tanθ_P
tan(β/2)=(D₂-D₁)/2L
L₀=D₂L/(D₂-D₁)
n_Psinθ_P= sin θ
and
L : Length of the light guide member in the optical axis direction (mm)
θ : The maximum value (°) of the angle between the light ray incident on the center of the light-incidence side end face of the light guide member and the normal line of the light-incidence side end face.
D₁: Diameter (mm) of the inscribed circle of the light incident side end surface of the light guide member
D₂: Diameter of the inscribed circle of the light-emitting side end face of the light guide member (mm)
n_P: refractive index of the light guide member
and D₁=D₂in the case of,
α/β=Ltanθ_p/D₂>2
It is. The objective optical system includes a front lens system located on the side of the light source to be measured, a rear lens system located on the side of the light guide member, and regulating a spread angle of light emitted from one point of the light source to be measured. and an aperture to
The photometric device according to claim 1, wherein the diaphragm is located at a rear focal position of the front lens system. Each of the plurality of sensors of the light receiving unit includes a light receiving element whose light receiving surface is square or rectangular, and an optical filter disposed on the light incident side of the light receiving element,
3. The photometric device according to claim 1, wherein at least two of the optical filters transmit light in different wavelength ranges . Each of the plurality of sensors of the light receiving unit includes a light receiving element whose light receiving surface is square or rectangular, and an optical filter disposed on the light incident side of the light receiving element,
3. The photometric device according to claim 1, wherein at least two of the optical filters transmit light in wavelength ranges corresponding to mutually different color matching functions. Claims 1 to 4, wherein the irradiation range when the light emitted from the light emitting side end face of the light guide member irradiates the light receiving section includes all the light receiving ranges of the plurality of sensors of the light receiving section. The photometric device according to any one of. 6. The photometric device according to claim 1, wherein each of the plurality of sensors of the light receiving section has a measurement sensitivity corresponding to color matching functions X, Y, and Z. The light-incidence side end face and the light-output side end face of the light guide member are square,
7. The photometric device according to claim 1, wherein the plurality of sensors of the light receiving section have rectangular light receiving surfaces located at four corners of one rectangle, respectively.

Images