JP2016146283A - Light emitting device, lighting fixture and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device enabling an image sensor having an RGB color filter of a camera or the like to perform brighter imaging while maintaining high light-emitting efficiency, a lighting fixture and a lighting system.SOLUTION: A light-emitting device 20 emits light having spectral distribution within a scope of 380-780 nm corresponding to a visible wavelength band. In the spectral distribution, the ratio of the sum of the light emission energy of 480-530 nm, and the light-emission energy of 620-630 nm to the light emission energy in the visible wavelength band accounts for 27% or more and 53% or less.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a light emitting device, a lighting fixture, and a lighting system.

  Surveillance devices such as surveillance cameras installed for security purposes in streets and parks are known. In addition, an emergency call system in which an illumination lamp, a monitoring camera, and an emergency call system are integrated has been proposed (Patent Document 1).

JP 2003-317176 A

  For example, in an environment where there is little natural light, such as indoors where outside light does not enter or outdoors at night, a device equipped with an image sensor having an RGB color filter, such as a surveillance camera, cannot avoid the light of a lighting fixture.

  In the emergency call system described in Patent Document 1, the camera is photographed by illuminating the surroundings with light from a lighting fixture.

  However, the brightness of the light from the lighting fixture is determined by a standard based on the spectral sensitivity of the human eye, and is determined for an apparatus that includes an image sensor having an RGB color filter, such as a camera. Not. In other words, the apparent brightness felt by the human eye does not match the brightness of the captured image of the camera. For example, in a dim night that is illuminated by outdoor lighting, only the sensitivity of the human eye is taken into consideration in a lighting fixture equipped with an existing light emitting device. Therefore, with the light of the existing light-emitting device, an image sensor having an RGB color filter such as a monitoring camera may not receive a sufficient amount of light and may take an unclear image. Further, when the light emitting device emits light based on the spectral sensitivity of the image sensor having the RGB color filter, the image sensor having the RGB color filter can perform bright photographing, but the apparent brightness may be dark. That is, the light emission efficiency of the light emitting device may be lowered. Here, the luminous efficiency is the total luminous flux per unit power (lumen per watt). A light emitting device with low luminous efficiency has a darker apparent brightness per unit power.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a light emitting device, a lighting fixture, and a lighting system that enable brighter shooting with respect to an image sensor having an RGB color filter such as a camera while maintaining high light emission efficiency. .

  A light-emitting device according to one embodiment of the present invention is a light-emitting device that emits light having a spectral distribution within a visible wavelength range of 380 nm to 780 nm, and the spectral distribution corresponds to emission energy in the visible wavelength range. The ratio of the sum of the emission energy of 480 nm to 530 nm and the emission energy of 620 nm to 630 nm is 27% or more and 53% or less.

  A lighting fixture according to one embodiment of the present invention includes the above light-emitting device.

  In addition, an illumination system according to one embodiment of the present invention includes the above-described lighting fixture that irradiates light on an object, and a camera that captures the object.

  According to the light-emitting device, the lighting fixture, and the lighting system according to one embodiment of the present invention, it is possible to perform brighter shooting with respect to an image sensor having an RGB color filter such as a camera while maintaining high luminous efficiency.

It is an external view of the illumination system which concerns on embodiment. It is sectional drawing of the lighting fixture which concerns on embodiment. It is a figure which compares the visibility of a human eye with the contribution function to the image brightness | luminance of a camera. It is a figure which shows the spectral sensitivity characteristic of a camera. It is a figure which shows an example of the spectral distribution of the light which a light-emitting device light-emits. It is a figure which shows the ratio of the emission energy of each wavelength band with respect to the emission energy of 380 nm to 780 nm. It is a figure which shows the improvement of the image brightness | luminance by the light-emitting device of embodiment.

  Below, the light-emitting device, lighting fixture, and lighting system which concern on embodiment of this invention are demonstrated in detail using drawing. Each of the embodiments described below shows a preferred specific example of the present invention. Therefore, the numerical values, shapes, materials, components, component arrangement, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Moreover, in each figure, the same code | symbol is attached | subjected about the same structural member.

(Embodiment)
The embodiment will be described below with reference to FIGS.

[Constitution]
First, the structure of the lighting fixture provided with the light-emitting device which concerns on embodiment, and this lighting fixture is demonstrated.

  FIG. 1 is an external view of a lighting system 1 according to an embodiment.

  The illumination system 1 is a system that is installed in an environment with little natural light, such as indoors where outside light does not enter or outdoors at night, for example, and is a monitoring system that photographs an object in a predetermined area.

  As shown in FIG. 1, the lighting system 1 includes a lighting fixture 10 and a camera 100.

  The lighting fixture 10 is a lighting fixture that illuminates an object to be photographed by the lighting system 1, and irradiates light emitted from a light emitting device 20 described later. The configuration of the lighting fixture 10 will be described with reference to FIG.

  The camera 100 is a camera that captures an object illuminated by the lighting fixture 10, and is, for example, a surveillance camera. Since the camera 100 includes an image sensor having an RGB color filter, the light of the lighting fixture 10 is required.

  Next, the structure of the lighting fixture 10 is demonstrated.

  FIG. 2 is a cross-sectional view of the lighting fixture 10 according to the embodiment.

  As illustrated in FIG. 2, the lighting fixture 10 includes a light emitting device 20, a housing 30, a light diffusion unit 40, a power supply control unit 50, and an external power supply line 60.

  The light emitting device 20 is a light emitting device that emits light having a spectral distribution (emission spectrum) within a visible wavelength range of 380 nm to 780 nm, and includes a circuit board 21 and a plurality of light emitting elements 22. In the present embodiment, the light emitting device 20 includes, for example, light emitting elements 22a to 22g. The light emitted from the light emitting device 20 has a characteristic spectral distribution, as will be described in detail later.

  The circuit board 21 is a board on which the light emitting element 22 is mounted.

  The light emitting element 22 is a light emitting element that emits light when supplied with electric power, and includes, for example, the light emitting elements 22a to 22g as described above. The light emitting elements 22a to 22g are, for example, LEDs (Light Emitting Diode). In the present embodiment, the light emitting elements 22a to 22g are configured by LEDs that emit red (R) light, green (G) light, or blue (B) light, respectively. The light emitting elements 22a to 22g are, for example, LEDs in which the light emitting element 22a emits red (R) light, LEDs in which the light emitting element 22b emits green (G) light, and light emitting elements 22c in blue (B) light. The LED is configured to emit light. And the light-emitting device 20 light-emits the light (illumination light) by the combination of RGB of the light emitting elements 22a-22g.

  The housing | casing 30 is a housing | casing of the lighting fixture 10, and the light-emitting device 20 is fixed. The housing 30 also has an opening 31.

  The opening 31 is an opening provided in the housing 30 and opens in a direction in which light emitted from the light emitting device 20 is irradiated.

  The light diffusing unit 40 is, for example, a light diffusing plate that diffuses and spreads the light emitted from the light emitting device 20 through the opening 31, and is fitted into the opening 31 so as to cover the light emitting device 20. That is, the light diffusing unit 40 also protects the light emitting device 20.

  The power control unit 50 generates power (for example, direct current power) for causing the light emitting element 22 to emit light from an external power source (for example, alternating current power). The electric power generated by the power control unit 50 is supplied to the light emitting element 22 through the circuit board 21.

  The external power supply line 60 is a power supply line that supplies power from the external power supply to the power supply control unit 50.

  The above is the configuration of the lighting fixture 10.

  By the way, the light brightness of the existing light-emitting device is determined by a standard based on the spectral sensitivity of the human eye, and an image sensor having an RGB color filter like the camera 100 is used for imaging. It is not set against. In other words, the human eye's visibility, which is a contribution function indicating the degree of contribution to the visual brightness felt by the human eye, and the contribution function indicating the degree of contribution to the image brightness (brightness of the captured image) are different. The image brightness of the camera 100 becomes darker than the apparent brightness. Specifically, when an object is illuminated with light from an existing light emitting device, the image brightness of a captured image of the object captured by the camera 100 may be darker than the apparent brightness of the object.

[Contribution function to human eye visibility and image brightness]
Here, the visibility of the human eye and the contribution function to the image brightness of the camera 100 will be described.

  FIG. 3 is a diagram comparing the visibility of the human eye and the contribution function to the image brightness of the camera 100. The visual sensitivity P (λ) of the human eye is represented by a dotted line, and the contribution function C (λ) to the image brightness of the camera 100 is represented by a solid line.

  The visual sensitivity of the human eye has a distribution with the maximum sensitivity at 555 nm.

  On the other hand, the contribution function C (λ) to the image brightness of the camera 100 has a distribution different from the visual sensitivity P (λ) of the human eye. The contribution function C (λ) to the image brightness of the camera 100 is calculated from the characteristics shown in FIG. 4, as will be described later.

  FIG. 4 is a diagram showing the spectral sensitivity characteristics of the camera 100. Specifically, FIG. 4 shows the standard spectral sensitivity of a high-definition camera having an RGB color filter recommended by the European Broadcasting Union (EBU). The spectral sensitivity characteristic r (λ) for the red color filter is represented by a solid line, the spectral sensitivity characteristic g (λ) for the green color filter is represented by a dashed line, and the spectral sensitivity characteristic b (λ) for the blue color filter is represented by a dotted line.

  The contribution function C (λ) to the image brightness of the camera 100 is calculated from the spectral sensitivity characteristics of the camera having the RGB color filter shown in FIG. Specifically, it is obtained using the following equation.

  Here, l, m, and n are predetermined coefficients. That is, the contribution function C (λ) to the image brightness of the camera 100 is calculated by multiplying r (λ), g (λ), and b (λ) by a predetermined coefficient and adding them.

  As shown in FIG. 3, the contribution function C (λ) to the image luminance has a wavelength band having higher sensitivity than the visual sensitivity P (λ) of the human eye. Therefore, the light having a spectral distribution having a high emission energy in the wavelength band in which the sensitivity of the contribution function C (λ) to the image luminance is higher than the visual sensitivity P (λ) of the human eye has the image luminance of the camera 100. To enable the camera 100 to capture bright images. Here, the emission energy is obtained by integrating the relative intensity of light indicated in the spectral distribution over a predetermined wavelength band. Specifically, the emission energy is an area in a predetermined wavelength band of the spectral distribution.

  However, when the sum of the emission energy in a predetermined wavelength band is constant, light having high emission energy in a part of the predetermined wavelength band has light emission energy in a wavelength band other than the predetermined wavelength band. Lower. In other words, when the area in a predetermined wavelength band of the spectral distribution is constant, light having a large area in a part of the predetermined wavelength band of the spectral distribution is not in a part of the wavelength band of the spectral distribution. The area in the wavelength band is reduced. Specifically, light having a high emission energy in a wavelength band (for example, 480 nm or less, or 630 nm or more, etc.) where the sensitivity of the contribution function C (λ) to the image luminance is high is a visual sensitivity P (λ ), The emission energy in the wavelength band with high sensitivity is reduced. Therefore, when the sum of the emission energy is constant, the apparent brightness of light having high emission energy in a wavelength band where the sensitivity of the contribution function C (λ) to the image luminance is high may be dark. As a result, a light emitting device that emits light having high light emission energy in a wavelength band in which the sensitivity of the contribution function C (λ) to the image luminance is high may have low light emission efficiency. Here, the luminous efficiency is the total luminous flux per unit power (lumen per watt). A light emitting device with low luminous efficiency has a darker apparent brightness per unit power.

  Therefore, when the spectral distribution of light emitted from the light emitting device 20 has high light emission energy from 480 nm to 530 nm and from 620 nm to 630 nm, the light emission efficiency of the light emitting device 20 can be maintained high. Specifically, the light emission efficiency of the light emitting device 20 is 80% or more of the light emission efficiency of an existing light emitting device (for example, an outdoor LED).

[Features of light-emitting device]
Next, features of the light emitting device 20 will be described.

  The spectral distribution of the light emitted from the light emitting device 20 is higher in a predetermined wavelength band in a wavelength band in which the sensitivity of the contribution function C (λ) to the image brightness is higher than the visual sensitivity P (λ) of the human eye. Have energy. Here, the predetermined wavelength bands are 480 nm to 530 nm and 620 nm to 630 nm. That is, the light spectral distribution of the light emitting device 20 has high emission energy from 480 nm to 530 nm and from 620 nm to 630 nm. Specifically, the light spectral distribution of the light emitting device 20 is 27% of the sum of the light emission energy of 480 nm to 530 nm and the light emission energy of 620 nm to 630 nm with respect to the light emission energy of 380 nm to 780 nm which is the visible wavelength band. It is 53% or less. Furthermore, the ratio of the sum of the emission energy of 480 nm to 530 nm and the emission energy of 620 nm to 630 nm with respect to the emission energy of 380 nm to 780 nm may be narrower than 27% to 53%. Specifically, the light spectral distribution of the light-emitting device 20 is such that the ratio of the sum of the light emission energy of 480 nm to 530 nm and the light emission energy of 620 nm to 630 nm to the light emission energy of 380 nm to 780 nm, which is the visible wavelength band, is 35%. It may be 48% or less. Thereby, the light emission efficiency of the light emitting device 20 is 80% or more of the light emission efficiency of the existing light emitting device, which is high efficiency. That is, the light emitting device 20 can emit light having the same apparent brightness as the light emitted by the existing light emitting device while maintaining high luminous efficiency.

  Next, a specific example of light emitted from the light emitting device 20 will be described with reference to FIG.

  FIG. 5 is a diagram illustrating an example of a spectral distribution of light emitted from the light emitting device 20. FIG. 5 shows the spectral distribution of light from, for example, the light emitting devices 20a to 20c as the light emitting device 20, and the fluorescent lamp 200a as the existing light emitting device, for example. The light emitting device 20a is represented by a two-dot chain line, the light emitting device 20b is represented by a dotted line, the light emitting device 20c is represented by a one-dot chain line, and the fluorescent lamp 200a is represented by a solid line. Further, the wavelength bands of 480 nm to 530 nm and 620 nm to 630 nm are respectively indicated by broken lines.

  As shown in FIG. 5, the spectral distribution of light from the light emitting devices 20a to 20c has higher light emission energy from 480 nm to 530 nm and from 620 nm to 630 nm compared to the light from the fluorescent lamp 200a. Specifically, the ratio of the area from 480 nm to 530 nm and the area from 620 nm to 630 nm in the spectral distribution of light of each of the light emitting devices 20a to 20c is larger than the area from 380 nm to 780 nm. Specific numerical values are shown in FIG. 6 for the ratio of the emission energy of 480 nm to 530 nm and 620 nm to 630 nm and the ratio of the sum of the emission energy of 380 nm to 780 nm of each of the light emitting devices 20a to 20c.

  FIG. 6 is a diagram showing the ratio of the emission energy of each wavelength band to the emission energy of 380 nm to 780 nm.

  As shown in FIG. 6, the spectral distribution of the light emitted from the light emitting devices 20a to 20c is the ratio of the sum of the emission energy of 480 nm to 530 nm and the emission energy of 620 nm to 630 nm to the emission energy of 380 nm to 780 nm. 27% or more and 53% or less. Furthermore, the spectral distribution of the light emitted by the light emitting devices 20b and 20c is such that the ratio of the sum of the light emission energy of 480 nm to 530 nm and the light emission energy of 620 nm to 630 nm to the light emission energy of 380 nm to 780 nm is 35% or more and 48% or less. It becomes.

  Thus, the light spectral distribution of the light emitting device 20 has high emission energy from 480 nm to 530 nm and from 620 nm to 630 nm.

[Effects]
In an environment with little natural light, such as indoors where outside light does not enter or outdoors at night, a device including an image sensor having an RGB color filter, such as a surveillance camera, cannot avoid the light of a lighting fixture.

  However, in the lighting fixture provided with the existing light-emitting device, only the sensitivity of the human eye is taken into consideration, and an image sensor having an RGB color filter such as a surveillance camera has a shortage of received light and takes an unclear image. There is a case.

  Therefore, the light-emitting device 20 according to the present embodiment is a light-emitting device that emits light having a spectral distribution in the visible wavelength range of 380 nm to 780 nm, and the light spectral distribution of the light-emitting device 20 has a visible wavelength. The ratio of the sum of the emission energy of 480 nm to 530 nm and the emission energy of 620 nm to 630 nm to the emission energy of the band is 27% or more and 53% or less.

  Accordingly, the light emitting device 20 enables brighter shooting with respect to a device including an image sensor having an RGB color filter such as the camera 100 while maintaining high light emission efficiency. That is, the spectral distribution of light of the light emitting device 20 has high emission energy in a wavelength band where the spectral sensitivity of the camera 100 (contribution function indicating the degree of contribution to image luminance) is high with respect to the visibility of the human eye. . And the conversion efficiency in the camera 100 increases, the amount of light received by the camera 100 increases, and the camera 100 can capture brighter and clearer images. At this time, the luminous efficiency of the light emitting device 20 is 80% or more of the luminous efficiency of the existing light emitting device. Accordingly, the light emitting device 20 maintains the high luminous efficiency (that is, the apparent brightness per unit power remains the same as the light of the existing light emitting device), and the image brightness of the captured image taken by the camera 100 is increased. Can be increased.

  In addition, the light emitting device 20 according to the present embodiment is a light whose ratio of the sum of the light emission energy of 480 nm to 530 nm and the light emission energy of 620 nm to 630 nm to the light emission energy in the visible wavelength band is 35% or more and 48% or less. Is emitted.

  Thereby, the light-emitting device 20 can further increase the image brightness of the captured image captured by the camera 100 while maintaining high light emission efficiency.

  The improvement of the image brightness of the captured image of the camera 100 will be specifically described with reference to FIG. Here, the ratio of the sum of the emission energy of 480 nm to 530 nm and the emission energy of 620 nm to 630 nm to the emission energy of 380 nm to 780 nm, which is the visible wavelength band, is referred to as an energy ratio.

  FIG. 7 is a diagram illustrating an improvement in image luminance by the light emitting device 20 according to the embodiment. Fluorescent lamps 200a and 200b and three LED light sources are shown as an example of an existing light emitting device, and light emitting devices 20a to 20c are shown as an example of the light emitting device 20 of the present embodiment. FIG. 7 shows the image brightness of the captured image when the camera 100 having the RGB color filter captures an object illuminated by each light emitting device. In addition, based on the image brightness of the captured image of the object illuminated with the light of the fluorescent lamp 200a among the existing light emitting devices (with a relative value of 1), the captured image of the object illuminated with the light of each light emitting device is used. Relative image brightness is shown. At this time, the apparent brightness of the object illuminated with the light of each light emitting device is the same.

  Like the light of the light emitting devices 20a to 20c shown in FIG. 7, the image brightness of the captured image of the object illuminated with light having a spectral distribution with an energy ratio of 27% or more and 53% or less is that of an existing light emitting device. It becomes higher than the image brightness of the captured image of the object illuminated with light. Further, like the light of the light emitting devices 20b and 20c shown in FIG. 7, the image brightness of the captured image of the object illuminated with light having a spectral distribution with an energy ratio of 35% to 48% is the existing luminance. This is 5% or more higher than the image brightness of the captured image of the object illuminated by the light from the light emitting device (fluorescent lamp 200a).

  As described above, in the light emitting device 20 of the present embodiment, the ratio of the light emission energy in the wavelength bands of 480 nm to 530 nm and 620 nm to 630 nm with respect to the light emission energy in the visible wavelength band of the light emitted from the light emitting device 20 is adjusted. Thereby, the light emitting device 20 of the present embodiment enables the camera 100 to capture a high image luminance even when light having the same apparent brightness as the light of the existing light emitting device is emitted.

  The average color rendering index (Ra) of the light emitted from the light emitting device 20 is preferably 60 or more. For example, the light emitting devices 20a to 20c of the present embodiment have an average color rendering index of 64, 67, and 64, respectively. Therefore, the average color rendering index of the light emitted from the light emitting device 20 becomes 60 or more by adjusting the spectral distribution like the spectral distribution of the light emitted by the light emitting devices 20a to 20c of the present embodiment.

  As a result, the light emitting device 20 of the present embodiment allows the camera 100 to have good color reproducibility (average color rendering index of 60 or more) and to capture a higher image luminance while maintaining high luminous efficiency. to enable.

  The average color rendering index of light emitted from the light emitting device 20 is more preferably 80 or more. For example, by further adjusting the spectral distribution of the light emitted from the light emitting device 20, the average color rendering index of the light emitted from the light emitting device 20 becomes 80 or more.

  As a result, the light emitting device 20 of the present embodiment has a high color reproducibility (average color rendering index of 80 or more) and a higher image luminance while maintaining high luminous efficiency. to enable.

  The lighting fixture 10 according to the present embodiment includes a light emitting device 20.

  Thereby, the lighting fixture 10 can irradiate the camera 100 with light that enables photographing with higher image luminance.

  In addition, the illumination system 1 according to the present embodiment includes a lighting fixture 10 that irradiates light on an object and a camera 100 that captures the object.

  Thereby, in the illumination system 1, the lighting fixture 10 illuminates the object in a predetermined area | region, and the camera 100 can image | photograph the picked-up image of the object used as a higher image brightness | luminance.

  As described above, the light emitting device 20, the lighting fixture 10, and the lighting system 1 according to the present embodiment enable brighter shooting with respect to an image sensor having an RGB color filter such as a camera while maintaining high luminous efficiency. .

  Although the light emitting device, the lighting fixture, and the lighting system according to the present invention have been described based on the above embodiments, the present invention is not limited to the above embodiments.

  For example, in the above-described embodiment, as illustrated in FIG. 1, in the lighting system 1, the lighting fixture 10 and the camera 100 are separate bodies, but the present invention is not limited thereto. For example, the lighting fixture 10 and the camera 100 may be integrated.

  Moreover, in said embodiment, although the lighting fixture 10 is provided with the light-emitting device 20, the housing | casing 30, the light-diffusion part 40, the power supply control part 50, and the external power supply line 60, it is not restricted to this. For example, the lighting fixture 10 may include at least the light emitting device 20 and the housing 30.

  In the above embodiment, the light emitting device 20 includes the plurality of light emitting elements 22a to 22g configured by LEDs that emit red (R) light, green (G) light, or blue (B) light. Although the light emitting element 22 comprised is provided, it is not restricted to this. For example, the light emitting device 20 may include a fluorescent lamp or the like that can emit light having a desired spectral distribution as the light emitting element 22.

  Moreover, in said embodiment, although the light-emitting device 20 was comprised from the circuit board 21 and the light emitting element 22 mounted in the circuit board 21, it is not restricted to this. For example, the light emitting device 20 may not include the circuit board 21. When the light emitting device 20 includes, for example, a fluorescent lamp as the light emitting element 22, the fluorescent lamp may be directly attached to the housing 30.

  Other forms obtained by subjecting the embodiments to various modifications conceived by those skilled in the art, and forms realized by arbitrarily combining the components and functions in the embodiments without departing from the spirit of the present invention. Are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Lighting system 10 Lighting fixture 20, 20a, 20b, 20c Light-emitting device 100 Camera

Claims (6)

A light-emitting device that emits light having a spectral distribution within a visible wavelength range of 380 nm to 780 nm,
In the spectral distribution, the ratio of the sum of the emission energy of 480 nm to 530 nm and the emission energy of 620 nm to 630 nm to the emission energy in the visible wavelength band is 27% or more and 53% or less.
Light emitting device. In the spectral distribution, the ratio of the sum of the emission energy of 480 nm to 530 nm and the emission energy of 620 nm to 630 nm with respect to the emission energy in the visible wavelength band is 35% or more and 48% or less.
The light emitting device according to claim 1. The average color rendering index of the light is 60 or more,
The light emitting device according to claim 1. The average color rendering index of the light is 80 or more,
The light emitting device according to claim 1. The light-emitting device according to claim 1 is provided.
lighting equipment. The lighting fixture according to claim 5, which irradiates light on an object;
And a camera for photographing the object.

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