JP2019003841A - Street lighting fixture - Google Patents

Abstract

To provide a street lighting fixture which enhances visibility of pedestrians walking on the street, pedestrians walking oppositely from them, bicycles, steps, exposed objects and the like under a dim visual environment, and which makes an atmosphere of a space favorable.SOLUTION: A street lighting fixture 100 is mounted on a columnar member 110 so that height from a street 200 is 2 m or higher and 5 m or lower, and it has a light emitting part 300 for emitting white light toward the street 200. In the white light, correlation color temperature is 5000K or higher and 6500K or lower, color deviation is -10 or greater and +10 or less, and an S/P ratio, which is a ratio of a luminous flux in scotopic vision and a luminous flux in a photopic vision, is 2.0 or greater, and average horizontal surface illuminance on an irradiation surface LA on the street 200 to which the white light is radiated is 1 lx or greater.SELECTED DRAWING: Figure 6

Description

  The present disclosure relates to street lighting equipment.

  Luminaires used for street lighting are required to improve the visibility of pedestrians, bicycles, steps, exposed objects, etc. that pass through the streets, and ensure safety in terms of traffic and crime prevention. By the way, the human visual sensitivity is different between photopic vision, scotopic vision, and faint vision. In photopic vision (in a bright environment), color can be perceived by the action of cone cells. In dark place (in a dark environment), the pyramidal cells do not function so that color cannot be perceived, but the visibility is improved by the function of rod cells.

  In addition, in light vision (in a dim environment), it is an intermediate state between photopic vision and dark vision, and both pyramidal cells and rod cells function. It is said that the brightness at which a person becomes dimmed is about 0.01 to 10 lx. When the brightness is higher than this, the photopic vision is obtained. .

  Here, in a dark environment, the visibility peak shifts to the short wavelength side in a bright environment. Such a phenomenon is well known as the Purkinje phenomenon. In addition, the number of pyramidal cells is large on the center side of the retina, and the number decreases dramatically when they are separated from the center side. Increases rapidly. For this reason, a pedestrian who walks on a street in thin vision often views, for example, the opponent's face or the like by central vision, and visually recognizes an exposed item beside the street. As a lighting fixture using the Purkinje phenomenon, for example, there is an outdoor lighting fixture disclosed in Patent Document 1.

JP 2008-091232 A

  Conventionally, as an example of a lighting device using the above-described Purkinje phenomenon, there is a lighting device for outdoor use. Here, as the correlated color temperature increases, the S / P, which is the visibility evaluation index in a dimmed vision environment, tends to increase. Therefore, irradiation with light having a correlated color temperature higher than 7100K is performed, and a street walk is performed in a dimmed vision environment. Visibility of pedestrians to improve. The S / P ratio is a numerical value for evaluating the visibility of light. The higher the S / P ratio, the higher the visibility in a dimmed vision environment.

  Conventional luminaires are luminaires that emphasize pedestrian visibility, but in outdoor walking spaces, it is possible to achieve both good visibility of the space, visibility of opposing pedestrians, etc. and good atmosphere of the space. is important. However, in order to improve visibility, a high S / P ratio is preferable. Therefore, a high correlated color temperature is suitable. However, in order to improve the atmosphere of the space, a low correlated color temperature is favorable. It is difficult to achieve both visibility and good atmosphere.

  Therefore, the present disclosure provides a street lighting device that enhances visibility and improves the atmosphere of a space in a low vision environment.

  A street lamp according to an aspect of the present disclosure is disposed at a height of 2 m or more and 5 m or less from a road surface, and includes a light emitting unit that irradiates the street with white light, and the white light has a correlated color temperature of 5000 K to 6500 K. The color deviation is −10 or more and +10 or less, the S / P ratio, which is the ratio of the luminous flux in dark place vision and the luminous flux in photopic vision, is 2.0 or more, and the town where the white light is irradiated The average horizontal illuminance on the irradiation surface on the road is 1 lx or more.

  According to the street lighting device of the present disclosure, the visibility of pedestrians, bicycles, steps, exposed objects, etc. facing each other is improved and the atmosphere is viewed from a pedestrian passing through the street in a dim vision environment. Can be better.

Drawing 1 is a mimetic diagram showing the irradiation side of light with the lighting fixture for streets concerning an embodiment. FIG. 2 is an external perspective view of the street lighting device according to the embodiment. FIG. 3 is a plan view showing an internal configuration of the street lighting device according to the embodiment. FIG. 4 is an external perspective view showing the illumination light source according to the embodiment. FIG. 5 is a schematic cross-sectional view of the illumination light source taken along line VV in FIG. FIG. 6 is a diagram illustrating an emission spectrum of the street lighting device according to the example. FIG. 7 is a diagram showing an emission spectrum of the illumination light source according to Comparative Example 1. FIG. 8 is a plan view and a side view of a comparative verification experiment space of the illumination light source according to the example, the comparative example 1, and the comparative example 2. FIG. 9A is a diagram illustrating a result of a comparative verification experiment of visibility in the illumination light source according to Example, Comparative Example 1, and Comparative Example 2. FIG. 9B is a diagram illustrating a result of a comparative verification experiment of the atmosphere in the space in the illumination light source according to Example, Comparative Example 1, and Comparative Example 2. FIG. 10 is an external perspective view showing an illumination light source according to another embodiment. 11 is a schematic cross-sectional view of the illumination light source taken along line XI-XI in FIG.

(Embodiment)
Hereinafter, a street lighting device according to an embodiment will be described with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

  Each figure is a schematic diagram and is not necessarily shown strictly. Moreover, in each figure, the same code | symbol is attached | subjected to the substantially same structure, and the overlapping description may be abbreviate | omitted or simplified.

  In the following embodiments, expressions using “substantially” such as a substantially semicircular shape are used. For example, a substantially semicircular shape not only means that it is completely semicircular, but also means that it is substantially semicircular, that is, includes a difference of, for example, several percent. The same applies to the case where expressions using other “abbreviations” are described.

[Configuration of street lighting equipment]
First, the street lighting device according to the embodiment will be described. Drawing 1 is a mimetic diagram showing the irradiation side of light with the lighting fixture for streets concerning an embodiment. As shown in FIG. 1, the street lighting device 100 is installed so as to irradiate the street 200 with light. The street lighting device 100 is supported above the street 200 by the columnar member 110. The street lighting device 100 is used in, for example, a living street. As shown in FIG. 1, a plurality of street lighting devices 100 are installed along a street 200 at a predetermined interval.

  The street lighting device 100 irradiates the road surface of the street 200 with light. The street lighting device 100 illuminates an irradiation surface LA (a region indicated by hatching of the street 200 in FIG. 1) on the road surface.

  The street lighting device 100 includes a lighting light source 310 to be described later, and thereby irradiates light that enhances the visibility in the low vision environment. In addition, the street lighting device 100 is installed at a height of 2 m or more and 5 m or less from the road surface of the street 200, and the average horizontal illuminance of the irradiation surface LA is set to be 1 lx or more. Here, the average horizontal plane illuminance is the illuminance per unit area in the light irradiated on the horizontal surface. In this specification, the average horizontal plane illuminance indicates the average illuminance of the irradiation surface LA that the street lighting device 100 irradiates the road surface of the street 200.

  The spread angle of the light emitted from the street lighting device 100 is not particularly limited as long as the street 200 is illuminated so that the average horizontal illuminance is 1 lx or more. The street lighting device 100 may be designed so that the street 200 is illuminated efficiently.

  Further, the white light emitted from the street lighting device 100 is irradiated to the street 200 side (downward side) using a housing 120 (see FIG. 3) described later, a reflector or a lens (not shown), and the like. Yes. This is because, for example, when the street lighting device 100 emits white light at night, if the light is irradiated above the street lighting device 100, the scenery deteriorates due to the light being applied to the night sky, and the surrounding animals and plants This is because there is a risk of causing light damage such as adversely affecting the light. Therefore, most of the white light emitted from the street lighting device 100 may be irradiated to the lower side of the street lighting device 100. For example, the white light irradiated upward from the street lighting device 100 is set to 5% or less of the total luminous flux in the white light. The “upper side” or “lower side” from the street lighting device 100 means, for example, that the angle of light emitted from the street lighting device 100 is inclined upward or downward with respect to the horizontal direction. It means whether it is.

Moreover, the light quantity with which the white light which the street lighting fixture 100 emits is irradiated to a horizontal direction and upward is set so that it may become small. This is because in a lighting device with a wide light distribution angle, a pedestrian on the street 200 may feel white light emitted by the lighting device as glare. Thus, in order to suppress the pedestrian on the street from feeling white light as glare, for example, the luminance value of the vertical angle of 85 degrees or more in the white light irradiated by the street lighting device 100 is 20000 cd / m ² or less. Set to In order to achieve the luminance value at the vertical angle, the street lighting device 100 uses a housing 120 (see FIG. 3) described later, a reflector or a lens (not shown), and the luminance value at a vertical angle of 85 degrees or more. It is comprised so that it may become 20000 cd / m < ² > or less.

  Hereinafter, a detailed configuration of the street lighting device 100 will be described.

  FIG. 2 is an external perspective view of the street lighting device 100 according to the embodiment. FIG. 2 is an external perspective view when the street lighting device 100 is viewed from below when the street lighting device 100 is installed on the street 200. FIG. 3 is a plan view showing an internal configuration when the translucent cover 130 of the street lighting device 100 according to the embodiment is removed and viewed. As shown in FIGS. 2 and 3, the street lighting device 100 includes a housing 120, a translucent cover 130, and a light emitting unit 300.

  The housing 120 accommodates the light emitting unit 300 and holds the translucent cover 130 that covers the accommodated light emitting unit 300. The casing 120 is formed using, for example, a metal material, but may be formed using other materials such as a resin material. Further, the inner surface of the housing 120 may be formed of a light reflecting material in order to increase the light utilization efficiency.

  The translucent cover 130 is a cover member that transmits light from the light emitting unit 300, and is attached to the housing 120. The translucent cover 130 can be formed of, for example, a glass material or a transparent resin material such as acrylic or polycarbonate. The translucent cover 130 may have light diffusibility. The street lighting device 100 may not include the translucent cover 130.

  The light emitting unit 300 includes an optical lens 150.

  The optical lens 150 is a lens member for controlling the light distribution of light emitted from the illumination light source 310. For example, as shown in FIG. 3, a plurality of optical lenses 150 are arranged so as to cover each of a plurality of illumination light sources 310 provided in the light emitting unit 300. As a material of the optical member 150, for example, a transparent resin material such as an acrylic resin is employed.

  The light emitting unit 300 emits white light toward the street 200. Specifically, the light emitting unit 300 includes a plurality of illumination light sources 310 arranged in two rows in the long direction of the street lighting device 100. As will be described later, the illumination light source 310 includes, for example, a light emitting element and a phosphor that converts a part of light emitted from the light emitting element. The light emitting unit 300 only needs to include at least one illumination light source 310, and the number of illumination light sources 310 arranged is not limited.

  The street lighting device 100 may include a power supply unit 140 that supplies power to the lighting light source 310 to light the street lighting device 100. The power supply unit 140 includes a power supply circuit that converts AC power from a commercial power source into DC power and outputs the DC power to the illumination light source 310, for example. The power supply unit 140 may be built in the street lighting device 100 or may be installed separately from the street lighting device 100.

[Configuration of light source for illumination]
Next, the structure of the illumination light source 310 according to the embodiment will be described with reference to the drawings.

  FIG. 4 is an external perspective view of the illumination light source 310 according to the embodiment. FIG. 5 is a schematic cross-sectional view of the illumination light source 310 taken along the line VV of FIG.

  As shown in FIGS. 4 and 5, the illumination light source 310 according to the embodiment is realized as an SMD (Surface Mount Device) type light emitting device. As will be described later, the illumination light source 310 can emit white light that is perceived brightly in the central vision and the peripheral vision under the twilight vision environment. For this reason, the illumination light source 310 is suitable for a street lighting apparatus used in an environment where the surroundings are dark such as at night.

  The illumination light source 310 includes a container 311 having a recess, a sealing member 312 sealed in the recess, and an LED (Light Emitting Diode) chip (light emitting element) 313 mounted in the recess.

  The container 311 is a container that houses the LED chip 313 and the sealing member 312. The container 311 includes an electrode 314 that is a metal wiring for supplying power to the LED chip 313. The LED chip 313 and the electrode 314 are electrically connected by a bonding wire 315. The material of the container 311 is, for example, metal, ceramic, or resin.

  As the ceramic, aluminum oxide (alumina), aluminum nitride, or the like is employed. As the metal, for example, an aluminum alloy, an iron alloy, or a copper alloy having an insulating film formed on the surface is employed. As the resin, for example, glass epoxy made of glass fiber and epoxy resin is employed. In addition, the material of the container 311 may be employed in combination with the above materials.

  As the container 311, for example, a material having a relatively high light reflectance (for example, a light reflectance of 90% or more) may be employed. By using a material having a relatively high light reflectance as the container 311, the light emitted from the LED chip 313 can be reflected on the surface of the container 311. As a result, the light extraction efficiency of the illumination light source 310 is improved. Further, the inner surface of the container 311 in which the LED chip 313 is disposed may be processed so as to increase the light reflectance.

  The LED chip 313 is an example of a light emitting element, and is a blue LED chip that emits blue light. The LED chip 313 is a gallium nitride LED chip having a center wavelength (emission peak wavelength of emission spectrum) of 430 nm or more and 460 nm or less made of, for example, an InGaN (indium / gallium / nitride) material.

  The sealing member 312 is a sealing member that seals at least a part of the LED chip 313, the bonding wire 315, and the electrode 314. The sealing member 312 includes a wavelength conversion material that converts a part of the wavelength of light emitted from the LED chip 313. Specifically, the sealing member 312 is made of a translucent resin material including a plurality of green phosphors 317a and a plurality of red phosphors 317b as wavelength conversion materials. Although it does not specifically limit as a translucent resin material, For example, a methyl-type silicone resin, an epoxy resin, or a urea resin etc. may be used.

The green phosphor 317a is an example of a phosphor (phosphor particle), is excited by blue light from the LED chip 313, and emits green light having a wavelength different from that of the blue light from the LED chip 313. Specifically, a Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor having a center wavelength of light of 540 nm or more and 550 nm or less is employed as the green phosphor 317a.

As will be described later, in the illumination light source 310, the S / P ratio of white light emitted from the illumination light source 310 is increased. The S / P ratio is an evaluation index for visibility in a dimmed vision environment. The higher the S / P ratio, the higher the visibility in the low vision environment. Here, in order to increase the S / P ratio, it is effective to increase the light component in the blue-green region having a wavelength of 480 nm or more and 520 nm or less. In order to increase the light component in the blue-green region, Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor is effective from the viewpoint of high wavelength conversion efficiency.

_Then, Lu ₃ Al ₅ O 12: ^{If Ce 3+} phosphor is employed, if the center wavelength of the light is less than 540 nm, decreases the wavelength conversion efficiency. On the other hand, when the center wavelength of light is larger than 550 nm, the effect of increasing the light component in the blue-green region, that is, the effect of increasing the S / P ratio is reduced. Therefore, in the embodiment, a Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor having a center wavelength of light of 540 nm or more and 550 nm or less is employed.

  Note that any phosphor may be employed as the green phosphor 317a as long as a later-described emission spectrum can be realized as long as the decrease in light conversion efficiency is acceptable. For example, as the green phosphor 317a, an yttrium aluminum garnet (YAG) phosphor may be employed. For example, a halosilicate phosphor may be employed as the green phosphor 317a. Further, for example, an oxynitride phosphor may be employed as the green phosphor 317a.

The red phosphor 317b is an example of a phosphor, and is excited by light from the LED chip 313, and emits red light having a wavelength different from that of the blue light from the LED chip 313. Specifically, a (Sr, Ca) AlSiN ₃ : Eu ²⁺ phosphor having a center wavelength of light of 610 nm or more and 620 nm or less is employed for the red phosphor 317b. In addition, as long as the light emission spectrum mentioned later is realizable, what kind of fluorescent substance may be employ | adopted for the red fluorescent substance 317b.

  With the above configuration, part of the blue light emitted from the LED chip 313 is converted into green light by the green phosphor 317 a included in the sealing member 312. Similarly, the other part of the blue light emitted from the LED chip 313 is wavelength-converted into red light by the red phosphor 317 b included in the sealing member 312. The blue light that has not been absorbed by the green phosphor 317a and the red phosphor 317b, the green light that has been wavelength-converted by the green phosphor 317a, and the red light that has been wavelength-converted by the red phosphor 317b are a sealing member. Diffusion and mixing in 312. As a result, white light is emitted from the sealing member 312. That is, the illumination light source 310 emits white light by mixing the light from the LED chip 313 and the light emitted from the green phosphor 317a and the red phosphor 317b.

  Hereinafter, examples of the emission spectrum of white light emitted from the illumination light source 310 and Comparative Example 1 will be described.

[Example]
FIG. 6 is a diagram illustrating an emission spectrum of the illumination light source 310 according to the example. In addition, the vertical axis | shaft of FIG. 6 is normalized by setting the intensity | strength of the light of wavelength 450nm as 1.0 in an emission spectrum.

The illumination light source 310 according to the embodiment includes an LED chip 313 having an emission peak at a wavelength of 450 nm, a green phosphor 317a (Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor) having an emission peak at a wavelength of 545 nm, and a wavelength of 615 nm. And a red phosphor 317b ((Sr, Ca) AlSiN ₃ : Eu ²⁺ phosphor) having an emission peak. In the illumination light source 310 according to the embodiment, the mixing amount of the green phosphor 317a and the red phosphor 317b is adjusted so that the correlated color temperature of the white light emitted from the illumination light source 310 is 5500K. . That is, the correlated color temperature of the white light emitted from the illumination light source 310 according to the embodiment is 5500K.

  As shown in FIG. 6, the ratio of the light intensity at a wavelength of 510 nm to the light intensity at the first peak (wavelength 450 nm) of the emission spectrum is 0.47. The ratio of the light intensity at a wavelength of 580 nm (a1 in FIG. 6) to the light intensity at the first peak of the emission spectrum is 0.60. Further, the ratio (b1 / a1 in FIG. 6) of the light intensity (b1 in FIG. 6) at the wavelength 650 nm to the light intensity at the wavelength 580 nm is 0.45. In addition, the emission spectrum of the illumination light source 310 according to the example has a second peak at a wavelength of 580 nm. The second peak means a portion having the next highest light intensity after the emission peak (first peak) having a wavelength of 450 nm. Further, the color deviation (Duv) of the illumination light source 310 according to the example is −0.80. Here, the color deviation is a deviation from the color temperature on the black body locus.

  The average color rendering index (Ra) of white light emitted from the illumination light source 310 according to the example is 80. The white light emitted from the illumination light source 310 according to the example has an S / P ratio of 2.0, which is a ratio of a luminous flux in dark place vision and a luminous flux in photopic vision.

The S / P ratio is an evaluation index for visibility in a dimmed vision environment. The higher the S / P ratio, the higher the visibility in the low vision environment. The S / P ratio (R _SP ) is, for example, when V (λ) is the spectral luminous efficiency in photopic vision of the illumination light source 310 and V ′ (λ) is the spectral luminous efficiency in scotopic vision, It can be calculated based on the following formula (1).

In Equation (1), K is the maximum photopic visual sensitivity (= 683 lm / W), K ′ is the maximum scotopic visual sensitivity (= 1699 lm / W), and Φ _e (λ) Is the spectral total radiant flux of the illumination light source 310.

[Comparative Example 1]
FIG. 7 is a diagram showing an emission spectrum of the illumination light source according to Comparative Example 1.

The illumination light source according to Comparative Example 1 has the same overall configuration as that of the illumination light source 310, but the phosphor contained in the sealing member is different. Specifically, the illumination light source according to Comparative Example 1 includes an LED chip having an emission peak at a wavelength of 450 nm, and a green phosphor (Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor) having an emission peak at a wavelength of 555 nm. Is provided. The illumination light source according to Comparative Example 1 does not include a red phosphor. In the illumination light source according to Comparative Example 1, the mixing amount of the green phosphor is adjusted so that the correlated color temperature of the white light emitted from the illumination light source is 5000K. That is, the correlated color temperature of white light emitted from the illumination light source according to Comparative Example 1 is 5000K.

  As shown in FIG. 7, the ratio of the light intensity at a wavelength of 510 nm to the light intensity at the emission peak (wavelength 450 nm) of the emission spectrum is 0.27. The ratio of the light intensity at a wavelength of 580 nm (A1 in FIG. 7) to the light intensity at the emission peak of the emission spectrum is 0.66. The ratio (B1 / A1 in FIG. 7) of the light intensity at wavelength 650 nm (B1 in FIG. 7) to the light intensity at wavelength 580 nm is 0.40.

  The average color rendering index of white light emitted from the illumination light source according to Comparative Example 1 is 70. The S / P ratio of white light emitted from the illumination light source according to Comparative Example 1 is 1.7.

[Impression evaluation]
Next, with reference to FIG. 8, FIG. 9A, and FIG. 9B, the verification result of the impression evaluation by the sensory test implemented using the illumination light source of the said Example and the said comparative example 1 is demonstrated. In the sensory test, an illumination light source of Comparative Example 2 that irradiates white light having a correlated color temperature of 8000 K was prepared, and comparative verification was performed together with the illumination light sources of Examples and Comparative Example 1. The illumination light source of Comparative Example 2 is the same as the illumination light source 310 in terms of the overall configuration, but the green phosphor so that the correlated color temperature of white light emitted from the illumination light source according to Comparative Example 2 is 8000K. And a light source in which the mixing amount of the red phosphor is adjusted. That is, the correlated color temperature of white light emitted from the illumination light source according to Comparative Example 2 is 8000K. The S / P ratio of white light emitted from the illumination light source according to Comparative Example 2 is 2.0 or more.

  FIG. 8 is a plan view and a side view for explaining a comparative verification experiment space of the illumination light source according to the example, the comparative example 1, and the comparative example 2. Specifically, FIG. 8A is a plan view (top view) for explaining the comparative verification experiment space of the illumination light source according to the example, the comparative example 1 and the comparative example 2, and FIG. (B) is a side view for demonstrating the comparison verification experiment space of the light source for illumination which concerns on an Example, the comparative example 1, and the comparative example 2. FIG.

  As shown in FIG. 8, in the comparative verification experiment space, the street lighting device 100 was installed at a height of 4.5 m from the road surface of the street 200. In addition, the subject U was positioned at a location that was a vertical angle of 60 ° from the street lighting device 100 and was 5.2 m away in the negative Y-axis direction. Further, the visual object V at a position 4.8 m away from the street lighting device 100 in the positive Y-axis direction was positioned. In addition, the subject U and the visual target V were positioned at a location 1.67 m away from the street lighting device 100 in the negative X-axis direction.

  The visual target V is a life-size doll (mannequin). The visual object V was provided with a color chart on which a plurality of different colors conforming to JIS Z 8721 were written.

  Under such conditions, the illumination light source of the street lighting apparatus 100 is replaced with the illumination light source of the example, comparative example 1 and comparative example 2, and the subject U recognizes with each illumination light source. The appearance (visibility) of the object V and the good atmosphere of the comparative verification experiment space were evaluated. In the comparative verification experiment, the experiment was performed under three conditions of 1 lx, 3 lx, and 7.5 lx for each of the illumination light sources according to the example, the comparative example 1, and the comparative example 2.

  FIG. 9A is a diagram illustrating a result of a comparative verification experiment of visibility in the illumination light source according to Example, Comparative Example 1, and Comparative Example 2. FIG. 9B is a diagram illustrating a result of a comparative verification experiment on the goodness of a space atmosphere in the illumination light sources according to the example, the comparative example 1, and the comparative example 2. Specifically, (a) of FIG. 9A is a case where the illuminance of each illumination light source is set to 1 lx, and (b) of FIG. 9A is a case where the illuminance of each illumination light source is set to 3 lx. (C) of FIG. 9A is a case where the illumination intensity of each illumination light source is set to 7.5 lx. 9B shows a case where the illuminance of each illumination light source is set to 1 lx, and FIG. 9B (b) shows a case where the illuminance of each illumination light source is set to 3 lx. (C) shows a case where the illuminance of each illumination light source is set to 7.5 lx.

  The number of subjects in the comparison target experiment is 29. Moreover, the result of the comparison object experiment was analyzed using the Scheffe paired comparison method. Specifically, first, each subject was confirmed with the visual target V in an environment in which white light was irradiated by the illumination light source according to the example, comparative example 1 or comparative example 2. Further, each subject was allowed to confirm the visual target V in an environment in which white light was irradiated by the illumination light source according to Example, Comparative Example 1 or Comparative Example 2 different from the confirmed illumination light source. The above-mentioned action was repeated a certain number of times at regular intervals. Furthermore, for each subject, how the white light by the illumination light source confirmed previously felt how the white light by the illumination light source confirmed later felt good visibility and the atmosphere of the space, − Evaluation was made with a relative score based on a 5-level rating scale of 2, -1, 0, 1 and 2. Note that positive is an evaluation that the subject felt good, and minus was an evaluation that the subject felt bad. Each subject can see how the shape of the visual target V looks in the experimental space, how different colors (the color charts described above) arranged on the visual target V appear, and the white line placed on the floor. , Planting, and appearance of the outer wall were evaluated as visibility.

  For example, first, the subject U is checked for white light irradiated at 1 lx in the illumination light source according to the example. Next, the subject U is made to confirm the white light irradiated at 1 lx in the illumination light source according to Comparative Example 1. Next, for the subject U, whether or not the white light of the illumination light source according to the example was better in visibility and the atmosphere of the space than the white light of the illumination light source according to Comparative Example 1 in five stages. Let me evaluate. In this way, the subject first confirms the visual target object V in the white light environment irradiated by the target illumination light source, and then in the white light environment irradiated by the illumination light source to be compared. The visual object V is confirmed. Furthermore, the subject sees how the white light emitted from the illumination light source to be felt feels compared to the white light emitted from the illumination light source to be compared, and the visibility of the visual object V (visual recognition). And the good atmosphere of the comparative verification experimental space. In this way, each subject is exposed to white light from three illumination light sources (Example, Comparative Example 1 and Comparative Example 2) under conditions of three illuminances (1lx, 3lx, 7.5lx). A comparative evaluation was conducted.

  The average preference shown on the vertical axis of the graphs shown in FIGS. 9A and 9B represents the preference of each condition as a value in the same dimension in the paired comparison, and indicates the degree of average preference. . Moreover, the significant difference shown to FIG. 9A and FIG. 9B is the value computed by the analysis of variance from the evaluation value of each test subject. When the scores of the two evaluation objects are more than this value, it is determined that there is a difference in superiority. For example, in (a) of FIG. 9A, the difference in score between the example and the comparative example 2 is 0.03, and since the value is smaller than the significant difference 0.29, there is no significant difference. On the other hand, the difference in score between the example and the comparative example 1 is 0.61, which is 0.29 or more, so that it can be determined that there is a dominant difference.

  As shown in FIGS. 9A and 9C, the illumination light source 310 according to the example has an average preference degree equivalent to that of the illumination light source according to the comparative example 2. Moreover, as shown to (b) of FIG. 9A, in the illumination light source 310 which concerns on an Example, the average preference degree higher than the illumination light source which concerns on the comparative example 2 was obtained. These results mean that each subject felt the same or better visibility with the illumination light source 310 according to the example and the illumination light source according to the comparative example 2. That is, it means that each subject felt that the higher the S / P ratio, the higher the visibility (the better the visibility), even when the correlated color temperature is close.

  In addition, as illustrated in FIGS. 9A, 9B, and 9C, the illumination light source 310 according to the example has an average preference degree equivalent to that of the illumination light source according to the comparative example 1. These results show that the white light from the illumination light source 310 according to the example and the white light from the illumination light source according to Comparative Example 1 have different S / P ratios, but the correlated color temperature is 5500K or 5000K. It means that the atmosphere of the same space is good.

  Further, as shown in (b) and (c) of FIG. 9B, in the illumination light source 310 according to the example, an average preference degree higher than that of the illumination light source according to the comparative example 2 was obtained. These results mean that each subject felt a better atmosphere in the space of the illumination light source 310 according to the example than the illumination light source according to the comparative example 2. That is, even if the S / P ratio is 2.0 or more, the correlated color temperature of 5500K means that each subject feels that the atmosphere of the space is good.

[Effects]
Next, the effects obtained by the illumination light source 310 according to the example will be described in comparison with the illumination light sources according to Comparative Example 1 and Comparative Example 2.

  The emission spectrum of white light emitted from the illumination light source 310 according to the example has an emission peak in the wavelength range of 430 nm or more and 460 nm or less. In addition, in the emission spectrum of white light emitted from the illumination light source 310 according to the example, the ratio of the light intensity at the wavelength 510 nm to the light intensity at the emission peak is 0.45 or more, and the light at the wavelength 580 nm with respect to the light intensity at the emission peak. The intensity ratio is 0.60 or more. In the emission spectrum of white light emitted from the illumination light source 310 according to the example, the ratio of the light intensity at a wavelength of 650 nm to the light intensity at a wavelength of 580 nm is 0.5 or less.

  In the illumination light source 310 having an emission spectrum that satisfies such conditions, the light component in the blue-green region having a wavelength of 480 nm or more and 520 nm or less is increased, and the S / P ratio of white light emitted from the illumination light source 310 can be increased. . Specifically, the S / P ratio of white light emitted from the illumination light source 310 can be set to 2.0 or more. Note that the S / P ratio is improved by shifting the emission peak wavelength of the LED chip 313 to the longer wavelength side. However, the luminous efficiency of the LED chip 313 decreases when the emission peak wavelength of the LED chip 313 is shifted to the longer wavelength side. Therefore, the emission peak wavelength of the LED chip 313 is preferably 430 nm or more and 460 nm or less. Furthermore, the emission peak wavelength of the LED chip 313 is more preferably 450 nm or more and 460 nm or less.

  Here, in a photopic environment, pyramidal cells having a spectral luminous efficiency peak at a wavelength of 555 nm are stimulated among the photoreceptor cells. Further, in a night vision environment such as a night road (street) space, rod cells having a peak of spectral luminous efficiency at a wavelength of 507 nm are stimulated in addition to the pyramidal cells. Since both pyramidal cells and rod cells are stimulated in the dim vision environment, the light component in the blue-green region having a wavelength of 480 nm or more and 520 nm or less in the emission spectrum is increased, whereby the illumination light source 310 is emitted. The S / P ratio of white light is increased.

  The S / P ratio is preferably 2.0 or more. Light with an S / P ratio of 2.0 or more is perceived brightly in peripheral vision. Peripheral vision means, for example, that a peripheral portion of a visual field having a viewing angle of 10 degrees or more is visually recognized, and the main active environment is a twilight vision environment or a dark vision environment. Therefore, the illumination light source 310 can emit white light that is perceived brightly in a low vision environment, particularly in peripheral vision.

  On the other hand, for example, the emission spectrum of the illumination light source according to Comparative Example 1 does not satisfy the condition where the S / P ratio is 2.0 or more. The illumination light source according to Comparative Example 1 has reduced visibility in a low vision environment.

  Further, the illumination light source 310 having an emission spectrum that satisfies the above conditions can emit white light that is perceived brightly even in central vision under a light vision environment due to the shape of the emission spectrum. The central vision means, for example, that the central part of the visual field having a viewing angle of about 2 degrees or more and less than 10 degrees is viewed, and the photopic vision environment is the main activity environment.

  In addition, the white light emitted from the illumination light source 310 according to the embodiment has a high color reproducibility because the average color rendering index is 80 or more. Therefore, the illumination light source 310 according to the embodiment can more accurately color the color information of the exposed material installed on the street 200 or in the periphery of the street 200. Therefore, color misidentification by pedestrians on the street 200 is reduced.

  On the other hand, for example, white light emitted from the illumination light source according to Comparative Example 1 has a low color reproducibility because the average color rendering index is 71. Therefore, the pedestrian on the street 200 has a concern of misidentifying the color. Therefore, as shown in FIG. 9A, each subject feels the same or better visibility than the illumination light source 310 of the example and the illumination light source of the comparative example 2, and the illumination light source of the example. It is presumed that this felt better visibility than the illumination light source of Comparative Example 1.

  In addition, the correlated color temperature of the white light emitted from the illumination light source 310 according to the embodiment is 5000K or more and 6500K or less. Thereby, the illumination light source 310 according to the embodiment can emit natural daylight white (daylight color) light with a clear bluish white line or the like on the street 200.

  On the other hand, the correlated color temperature of the white light emitted from the illumination light source according to Comparative Example 2 is 8000 K, which is a light blue color as compared with the illumination light source 310 according to the example. Therefore, as illustrated in FIG. 9B, it is assumed that the illumination light source 310 of the example felt that the subject U felt that the atmosphere of the space was better than the illumination light source according to Comparative Example 2.

  As described above, according to the illumination light source 310 of the embodiment, it is possible to achieve both good visibility of the space on the street 200 and good atmosphere of the space. The above characteristics and effects may be achieved as light emitted from the street lighting apparatus 100, and each of the plurality of illumination light sources 310 installed in the street lighting apparatus 100 achieves the above characteristics and effects. You don't have to. For example, in a street lighting device, a blue LED chip that emits blue light may be disposed in a light emitting unit, and a green phosphor and a red phosphor may be included in a translucent cover. By doing so, for example, the emission spectrum emitted from the street lighting device may be configured to be the emission spectrum shown in the above-described embodiment.

  The correlated color temperature of white light is more preferably 5200K or more and 6000K or less. By doing so, the light component in the blue region (for example, wavelength 400 nm or more and 500 nm or less) in the white light is further reduced, so that the scattering of the illumination light is suppressed when fog is generated. Therefore, the safety of a pedestrian when walking on the street is further improved.

  In addition, the color deviation of the illumination light source 310 according to the embodiment is −10.0 or more and +10.0 or less. Thereby, the light source 310 for illumination which concerns on an Example can emit more natural white light, without being much green or red. The color deviation is more preferably from −5.0 to +5.0. By doing so, the white light becomes a more natural white color, and for example, the white line on the street 200, the white color of the exposed material, etc. can be visually recognized more clearly.

Moreover, the lumen equivalent (LE) of the illumination light source 310 according to the embodiment is 300 lm / W or more. Here, the lumen equivalent is an index for evaluating the visibility per equal energy of light in photopic vision. In other words, light with a large lumen equivalent is interpreted as light with high visibility per light energy in photopic vision, that is, light that is easily perceived by cone cells. Furthermore, the illumination with a large lumen equivalent is interpreted as the illumination that is easily perceived by the pyramidal cells even in the dim vision. The lumen equivalent is, for example, that K is photopic maximum luminous sensitivity (= 683 lm / W), V (λ) is spectral luminous efficiency in photopic vision, and Φ _e (λ) is the spectral total efficiency of the illumination light source 310. In the case of the radiant flux, it can be calculated based on the following equation (2).

  Thereby, the light emitted from the light source 310 for illumination becomes light with a large proportion of light that is easily perceived by the pyramidal cells even in the dim vision. For this reason, the light emitted from the illumination light source 310 is light with high light energy utilization efficiency because it is bright for the street pedestrian in the central view and the peripheral view in the thin vision.

[Summary]
The street lighting device 100 according to Embodiment 1 includes a light emitting unit 300 that is disposed at a height of 2 m or more and 5 m or less from the road surface of the street 200 and that irradiates the street 200 with white light. The white light has a correlated color temperature of 5000 K or more and 6500 K or less, a color deviation of −10 or more and +10 or less, and an S / P ratio, which is a ratio of a luminous flux in dark place vision and a luminous flux in photopic vision, is 2.0. That's it. Moreover, the average horizontal illuminance on the irradiation surface LA on the street 200 irradiated with white light is 1 lx or more.

  Thereby, since the pedestrian in the street 200 illuminated by the white light emitted from the street lighting device 100 is illuminated by the white light perceived brightly by the peripheral vision, the table on the side of the street that can be captured by the peripheral vision. Visibility to goods is improved. Therefore, according to the street lighting apparatus 100, the safety at the time of a pedestrian's walk is improved.

  Further, the white light emitted by the street lighting device 100 has a correlated color temperature of 5000K to 6500K and a color deviation of −10 to +10. Therefore, the atmosphere of the space irradiated with the white light is good. If the atmosphere is a good space, an effect of enhancing the sense of security of pedestrians on the street 200 is expected.

  As described above, according to the street lighting device 100, the visibility of pedestrians and pedestrians passing through the street 200, bicycles, steps, exposed objects, and the like is improved in a light vision environment, and The atmosphere can be improved. According to the street lighting device 100 that can improve the visibility of pedestrians on the street 200 and can increase the sense of security, streets that accurately perceive opposing pedestrians and have a bad atmosphere in the space. Since the decrease in the number of 200 pedestrians can be suppressed, an effect is also expected as a crime prevention measure.

  Further, the average color rendering index of white light emitted from the street lighting device 100 may be 80 or more.

  Thereby, since the pedestrian of the street 200 can recognize a color more correctly, it can recognize more accurately the color information, such as a display thing (sign) installed on the street 200. In addition, the possibility of misidentification in the clothes of the opposite pedestrian or the color of the bicycle is reduced.

  Further, the emission spectrum of white light emitted from the street lighting device 100 may have an emission peak in the range of a lumen equivalent of 300 lm / W or more and a wavelength of 430 nm or more and 460 nm or less. In the emission spectrum, the ratio of the light intensity at the wavelength 510 nm to the light intensity at the emission peak may be 0.45 or more, and the ratio of the light intensity at the wavelength 580 nm to the light intensity at the emission peak may be 0.60 or more. . In the emission spectrum, the ratio of the light intensity at a wavelength of 650 nm to the light intensity at a wavelength of 580 nm may be 0.5 or less.

  Thereby, the white light emitted from the street lighting device 100 becomes white light that makes the pedestrian of the street 200 feel brighter and the waste of light energy is suppressed.

  Further, the light emitting unit 300 of the street lighting device 100 may include an illumination light source 310. The illumination light source 310 may include a light emitting element 313 and a plurality of phosphors that are excited by light from the light emitting element 313 and emit light having a wavelength different from that of the light from the light emitting element 313. In addition, the light-emitting element 313 may have an emission peak in a wavelength range of 430 nm to 460 nm. That is, for example, an LED chip 313 having a light emission peak in a wavelength range of 430 nm to 460 nm is employed as the light emitting element 313.

  Thereby, the illumination light source 310 can emit light that is brightly perceived in both peripheral vision and central vision, and has improved color reproducibility.

The plurality of phosphors may include a Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor having a light emission peak in a wavelength range of 540 nm to 550 nm. That is, for example, a Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor having high light conversion efficiency in the blue-green region is employed as the phosphor.

  Thereby, the illumination light source 310 can efficiently emit light that is brightly perceived in both peripheral vision and central vision and has improved color reproducibility.

The plurality of phosphors may include (Sr, Ca) AlSiN ₃ : Eu ²⁺ phosphors having emission peaks in the wavelength range of 610 nm to 620 nm. That is, as the phosphor, for example, (Sr, Ca) AlSiN ₃ : Eu ²⁺ phosphor having high light conversion efficiency in the red region is employed.

  Thereby, the illumination light source 310 can efficiently emit light that is brightly perceived in both peripheral vision and central vision and has improved color reproducibility.

  Further, the luminous flux of the white light emitted upward from the street lighting device 100 may be 5% or less of the total luminous flux in the white light.

  According to such a configuration, the white light emitted from the light emitting unit 300 is leaked upward from the street lighting device 100, for example, the brightness of the night sky, the lighting on the animals and plants around the street lighting device 100, for example. Adverse effects can be suppressed. That is, according to such a structure, the light pollution to the circumference | surroundings by the lighting fixture 100 for streets can be suppressed.

Further, the luminance value of the vertical angle of 85 degrees or more in white light may be 20000 cd / m ² or less.

  According to such a configuration, the pedestrian on the street is prevented from feeling white light as glare.

(Other embodiments)
As mentioned above, although the street lighting fixture which concerns on embodiment was demonstrated, this indication is not limited to the said embodiment.

  In the above embodiment, the illumination light source in which the light emitting element 313 is mounted on the container 311 has been described. However, the present invention is not limited to this. Below, the light source for illumination which concerns on other embodiment is demonstrated. FIG. 10 is an external perspective view showing an illumination light source according to another embodiment. 11 is a schematic cross-sectional view of the illumination light source taken along line XI-XI in FIG. As shown in FIGS. 10 and 11, the illumination light source 310 a includes a substrate 316 and an LED chip (light emitting element) 313 mounted on the substrate 316.

  The substrate 316 is a substrate having a wiring region where the electrode 314 is provided. The electrode 314 is a metal wiring for supplying power to the LED chip 313. The substrate 316 is, for example, a metal base substrate or a ceramic substrate. The substrate 316 may be a resin substrate having a resin as a base material.

  Further, as the substrate 316, a substrate having a high light reflectance (for example, a light reflectance of 90% or more) may be employed. By employing a substrate having a high light reflectance as the substrate 316, light emitted from the LED chip 313 can be reflected on the surface of the substrate 316. As a result, the light extraction efficiency of the illumination light source 310a is improved. An example of such a substrate is a white ceramic substrate based on alumina.

  In other embodiments, the substrate 316 is rectangular, but may be other shapes such as a circle.

  The sealing member 312 is a sealing member that seals at least part of the LED chip 313, the bonding wire 315, and the electrode 314. The sealing member 312 includes a wavelength conversion material that converts a part of the wavelength of light emitted from the LED chip 313. Specifically, the sealing member 312 is made of a translucent resin material including a plurality of green phosphors 317a and a plurality of red phosphors 317b as wavelength conversion materials.

  The sealing member 312 of the illumination light source 310a is formed in a dome shape so as to have a curvature on the substrate 316. Specifically, as shown in FIG. 11, the cross section of the sealing member 312 formed on the substrate 316 is formed in a substantially semicircular shape. By doing so, the sealing member 312 can collect the light emitted from the LED chip 313 and the light emitted from the wavelength conversion material sealed in the sealing member 312. That is, the sealing member 312 formed to have a curvature has a function of a lens that collects the light.

  Note that the cross-sectional shape of the sealing member 312 formed over the substrate 316 is not limited. By changing the curvature of the sealing member 312 to be formed, the light emitted from the lighting light source 310a and the street lighting device including the lighting light source 310a can be changed to a desired irradiation angle. By doing so, the illumination light source 310a and the street lighting device including the illumination light source 310a can illuminate the street 200 in a desired irradiation range without newly providing a lens or the like.

  Moreover, in the said embodiment, although said light emission spectrum was implement | achieved by two types of fluorescent substance and one LED chip (light emitting element), such an implementation method is an example and satisfy | fills said conditions Any phosphor and light emitting element may be used.

  For example, in the above embodiment, an LED chip is used as a specific example of the light emitting element. However, a semiconductor light emitting element such as a semiconductor laser, or a solid light emitting element such as an organic EL (Electro Luminescence) or an inorganic EL is used as the light emitting element. It may be adopted. For example, the illumination light source may include three or more types of phosphors having different fluorescence center wavelengths. In any case, if the above-described emission spectrum condition is satisfied, the street lighting device can emit light that is perceived brightly in both peripheral vision and central vision.

  Further, for example, in the above embodiment, the illumination light source realized as a light emitting module having an SMD structure has been described. However, the illumination light source of the present disclosure is a so-called COB (Chip On) in which an LED chip is directly mounted on a substrate. An LED module having a “Board” structure may be used.

  Further, the illumination light source of the present disclosure may be realized as a remote phosphor type light emitting module in which a resin member including a phosphor is disposed at a position away from the LED chip.

  Moreover, the street lighting fixture of this indication may be implement | achieved as remote phosphor type | mold illumination by which the resin member containing a fluorescent substance is arrange | positioned in the position away from the LED chip.

  In addition, the shape, structure, and size of the street lighting device of the present disclosure are not particularly limited, and the street lighting device of the present disclosure satisfies the conditions of the emission spectrum described in the above embodiment. Just fill it.

  In addition, the embodiment can be realized by variously conceiving various modifications to those embodiments, or by arbitrarily combining the components and functions in the embodiments without departing from the gist of the present disclosure. This form is also included in the present disclosure.

DESCRIPTION OF SYMBOLS 100 Street lighting fixture 200 Street 300 Light-emitting part 310, 310a Light source for illumination 313 LED chip (light emitting element)
317a Green phosphor (phosphor)
317b Red phosphor (phosphor)
LA irradiated surface

Claims (8)

A height from the road surface of the street is 2 m or more and 5 m or less, and includes a light emitting unit that irradiates the street with white light,
The white light is
Correlated color temperature is 5000K or more and 6500K or less,
The color deviation is -10 or more and +10 or less,
The S / P ratio, which is the ratio of the luminous flux in dark place vision and the luminous flux in photopic vision, is 2.0 or more,
An illumination device for a street, wherein an average horizontal illuminance on an illumination surface on which the white light is illuminated is 1 lx or more. The street lighting fixture according to claim 1, wherein the average color rendering index of the white light is 80 or more. The emission spectrum of the white light is
Lumen equivalent is 300 lm / W or more,
The wavelength has an emission peak in the range of 430 nm to 460 nm,
In the emission spectrum,
The ratio of the light intensity at a wavelength of 510 nm to the light intensity at the emission peak is 0.45 or more,
The ratio of the light intensity at a wavelength of 580 nm to the light intensity at the emission peak is 0.60 or more,
The street lighting device according to claim 1 or 2, wherein a ratio of light intensity at a wavelength of 650 nm to light intensity at a wavelength of 580 nm is 0.5 or less. The light emitting unit includes a light source for illumination,
The illumination light source is
A light emitting element;
A plurality of phosphors that are excited by light from the light emitting element and emit light having a wavelength different from that of the light from the light emitting element;
The street light fixture according to any one of claims 1 to 3, wherein the light-emitting element has a light emission peak in a wavelength range of 430 nm to 460 nm. The street lighting apparatus according to claim 4, wherein the plurality of phosphors include a Lu ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor having a light emission peak in a wavelength range of 540 nm to 550 nm. The street lighting apparatus according to claim 4 or 5, wherein the plurality of phosphors include (Sr, Ca) AlSiN ₃ : Eu ²⁺ phosphors having a light emission peak in a wavelength range of 610 nm to 620 nm. The street lighting fixture according to any one of claims 1 to 6, wherein the luminous flux of the white light irradiated upward from the street lighting fixture is 5% or less of the total luminous flux in the white light. The street lighting device according to any one of claims 1 to 7, wherein a luminance value of the vertical angle of 85 degrees or more in the white light is 20000 cd / m ² or less.

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