JP5486205B2 - Illumination method using task lighting apparatus and task lighting apparatus - Google Patents

Description

  The present invention relates to a lighting method for adjusting a circadian rhythm by a task lighting fixture and a task lighting fixture used therefor.

  Traditionally, in order to adjust the circadian rhythm, which is a biological rhythm with a period of about 24 hours, the face is exposed to high illuminance light during the day, especially in the morning, and as the face becomes as late as possible, especially during the late hours from evening to night. It is said that it is important for people not to be exposed to light.

  A hormone secreted at night and thought to be related to circadian rhythm, melatonin, was previously known to be secreted by exposure to light. Has a wavelength characteristic, and it is reported that melatonin secretion is further suppressed by light having a short wavelength. In general, the higher the correlated color temperature, the more the short wavelength component, the more the light incident on the eyes, the lower the color temperature, so that the suppression of melatonin secretion is prevented and the circadian rhythm is suppressed. Disturbance is prevented. Conversely, it has been found that exposure to light of short wavelengths during the day has the effect of adjusting the circadian rhythm. Therefore, try to keep the light of the highest possible color temperature in the daytime with the highest possible illuminance, and to keep the light out of the eyes as much as possible at night. It is desirable to make it soak.

  As lighting equipment that takes into account circadian rhythms, lighting fixtures are installed at high and low indoor locations, lighting fixtures installed at high locations are lit at high color temperatures, and lighting fixtures installed at low locations are at low color temperatures. An indoor lighting device that controls lighting is known (for example, see Patent Document 1).

  However, in the indoor lighting device described above, the lighting fixture in a low place, that is, a position close to the face, is lit in a time zone where the light is not desired as much as possible at night, so the eyes are exposed to light more than necessary, and the circadian rhythm is disturbed. . In addition, lighting devices with high color temperature that are lit during the day are installed in high places, and the distance from the face is far away, so the loss of light is large and energy is not saved. Moreover, it is necessary to control the lighting fixtures installed at two places, the high place and the low place, which is expensive.

  On the other hand, unlike general illumination that illuminates the entire indoor space with uniform illuminance, task-and-ambient illumination that is divided into ambient illumination that illuminates the entire space and task illumination that illuminates a work surface such as a desk surface is known. For example, as shown in FIG. 23, an ambient lighting fixture 102 for ambient lighting is disposed on a ceiling 101, and a task lighting fixture 103 for task lighting is erected on a desk. Task-and-ambient lighting is designed to save energy by reducing the illuminance of ambient lighting and ensuring the work surface has the illuminance necessary for visual work.

  The task-and-ambient lighting described above contributes to energy conservation as a whole, but it reduces the illuminance of the entire space and concentrates the light on the work surface. There is a risk of disturbance. On the other hand, in the evening and at night, an unnecessary amount of light is supplied to the face by the reflected light from the work surface, which may disturb the circadian rhythm.

JP 2000-260580 A

"Action Spectrum for Melatonin Regulation in Humans: Evidence for a Novel Circadian Photoreceptor" by G. C. Brainer, The Journal of Neuroscience, August 15, 2001, 21 (16), pp 6405-6612.

  This invention solves the said problem, and aims at making energy saving and adjustment of a circadian rhythm compatible in the task lighting fixture used for task and ambient lighting.

In order to achieve the above object, the invention according to claim 1 is a lighting method using a task lighting device for illuminating a work surface, and the time zone in which the task lighting device illuminates is at least a first work time zone. And the second work time zone, the task lighting device irradiates the face of the person who works in the first work time zone with direct light, and the direct light is applied to the vertical face of the face. The radiant flux of the direct light that suppresses the secretion of melatonin per unit area is 700 W or more, and the illumination light that irradiates the work surface without irradiating the face with direct light in the second work time period, The color temperature is set to 5000K or less.

  Here, the first work time zone is, for example, a day time zone, and the second work time zone is, for example, a time zone from evening to night.

According to a second aspect of the present invention, in the illumination method using the task lighting device according to the first aspect, the task lighting device includes a light emitting unit that irradiates the face with direct light, and the light emitting unit has an average luminance of 20000 cd. / M ² or less.

The invention of claim 3 is a task lighting device that illuminates a work surface, the task lighting device including a light emitting unit for a face that irradiates the face of a person who performs the work with direct light, and an illumination light on the work surface. A light emitting unit for the work surface that irradiates the light, and the direct light has a radiant flux of 700 W or more for suppressing the secretion of melatonin per unit area of the vertical face of the face, The color temperature is set to 5000K or less.

  According to a fourth aspect of the present invention, in the task lighting device according to the third aspect, the face light emitting section includes a filter that transmits light in a specific wavelength range, and direct light is irradiated onto the face through the filter. To do.

  According to a fifth aspect of the present invention, in the task lighting device according to the third aspect, the light emitting unit for the face and the light emitting unit for the work surface are an integrated light emitting unit, and the light emitting unit is positioned relative to the work surface. By changing, the presence or absence of direct light irradiation on the face is switched.

  A sixth aspect of the present invention is the task lighting fixture according to the third aspect, wherein the plurality of task lighting fixtures are fed from a duct of the same system.

  According to a seventh aspect of the present invention, in the task lighting fixture according to the third aspect, the average color rendering index (Ra) of the illumination light is 80 or more.

  According to the first aspect of the present invention, energy saving task-and-ambient illumination is performed by the task lighting device, and the irradiation of the light emitted by the task lighting device is changed according to the time zone. Since the circadian rhythm adjustment effect is obtained and the influence on the circadian rhythm is reduced in the second work time zone, both energy saving and circadian rhythm adjustment can be achieved.

  According to invention of Claim 2, the glare by direct light can be suppressed.

  According to the invention of claim 3, the same effect as that of the invention of claim 1 can be obtained.

  According to the invention of claim 4, by selecting a filter having a high transmittance in a relatively short wavelength region and a low transmittance in a long wavelength region out of the visible light wavelength region, the circadian light can be directly emitted by a short wavelength light. While maintaining the rhythm adjustment effect, direct light other than the short wavelength can be cut to reduce the average luminance and suppress the glare.

  According to the invention of claim 5, since the irradiation of the direct light on the face and the irradiation of the illumination light on the work surface are shared by the integrated light emitting unit, the instrument configuration is simplified.

  According to the invention of claim 6, a plurality of task lighting fixtures can be turned on and off collectively.

  According to the invention of claim 7, the visibility of the work surface can be maintained.

The side view of the lighting fixture for tasks used for the lighting method which concerns on the 1st Embodiment of this invention. The figure which shows an action spectrum. The table | surface which shows the experimental result which evaluated the biological rhythm adjustment effect by the melatonin action radiation flux, the working surface color temperature, and the light emission surface brightness, the influence on a biological rhythm, and a glare feeling. Sectional drawing of the light emission part in the lighting fixture for tasks which concerns on the modification of 1st Embodiment. Sectional drawing of the light emission part in the lighting fixture for tasks which concerns on another modification of 1st Embodiment. The figure which shows the spectral transmittance of the filter in the instrument. The block block diagram of the lighting fixture for tasks which concerns on the 2nd Embodiment of this invention. The perspective view of the lighting fixture. The side view of the lighting fixture. The perspective view explaining the example which changes the color temperature of the light source in the lighting fixture. The side view explaining the example which changes the color temperature of the light source in the lighting fixture. The perspective view explaining another example which changes the color temperature of the light source in the lighting fixture. The perspective view explaining another example which changes the color temperature of the light source in the lighting fixture. The enlarged view of the light source. The side view of the lighting fixture for tasks which concerns on the modification of 2nd Embodiment. The side view of the lighting fixture for tasks which concerns on another modification of 2nd Embodiment. The front view of the lighting fixture for tasks which concerns on the 3rd Embodiment of this invention. The side view of the lighting fixture. (A) is a plan view of a duct in the lighting fixture, (b) is a plan view of a light source module in the lighting fixture, (c) is a plan view of a human sensor module in the lighting fixture, and (d) is in the lighting fixture. The top view of a brightness sensor module. The front view of the lighting fixture for tasks which concerns on the modification of 3rd Embodiment. The side view of the lighting fixture. The perspective view of the 1st illumination duct in the same lighting fixture. External view of conventional task and ambient lighting.

(First embodiment)
A lighting method using a task lighting device (hereinafter referred to as a lighting device) according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the luminaire 1 is attached to a support portion 3 erected in the vicinity of the work surface 2 and illuminates the work surface 2. The illumination time zone by the luminaire 1 is divided into at least a first work time zone and a second work time zone. The first work time zone is a time zone during the day, particularly in the morning, and the second work time zone is a time zone from evening to night.

  The luminaire 1 includes a face light emitting unit 51 that irradiates the face of a person who works, that is, the user 4 with direct light 51L, and a work surface light emitting unit 52 that irradiates the work surface 2 with illumination light 52L. The light emitting unit 51 for the face and the light emitting unit 52 for the work surface may be integrated or configured separately (collectively referred to as the light emitting unit 5). The light emitting unit 5 includes a light source such as a fluorescent lamp or an LED. The closed curves 51L and 52L indicate the light distribution curves of the light emitting unit 51 for the face and the light emitting unit 52 for the work surface, respectively.

The luminaire 1 irradiates the face of the user 4 with direct light during a first work time, for example, during the day. The direct light has a radiant flux (hereinafter, melatonin action radiant flux ) that suppresses secretion of melatonin per unit area of the vertical face is 700 W (watt: hereinafter, unit notation) or more. In the second work time zone, for example, from evening to night, the direct light on the face is turned off or dimmed. Particularly at night, it is desirable to turn off direct light on the face. The illumination light applied to the work surface 2 in the second work time zone has a correlated color temperature of 5000 K or less, and reflected light from the work surface of the illumination light may be reflected by the eyes, and is preferably 3000 K or less. .

  The melatonin acting radiant flux M is obtained by the following equation 1 where Φ is the luminous flux and m is the relative melatonin acting coefficient.

The relative melatonin action coefficient m is k ₁ , k ₂ are constants, λ is a wavelength, B (λ) is an action spectrum, V (λ) is a standard luminous efficiency, and S (λ) is a spectral emission from the luminaire 1. When the bundle, S _white (λ), is a spectral radiant flux of an arbitrary general white light source such as a fluorescent lamp, the following formula 2 is obtained.

As shown in FIG. 2, the action spectrum B (λ) relating to melatonin suppression becomes a convex curve upward with respect to the wavelength λ in the wavelength range of 400 nm to 600 nm, and the wavelength λ has a peak at 464 nm (non-patented). Reference 1). This curve approximates the experimental result with a quartic function, and the square of the determination coefficient R ^2, that is, the correlation coefficient R is 0.91.

Facial for emitting portion 51 for irradiating direct light to the face, the average luminance is the 20000 cd / ^{m 2} or less, 10000 cd / ^{m 2} or less is desirable, 5000 cd / ^{m 2} or less is more desirable.

  FIG. 3 shows a result of the experiment using the luminaire 1. Here, the biological rhythm (circular rhythm) adjustment effect during the day, the influence on the biological rhythm at night, and the subject's glare sensation with respect to the melatonin action radiant flux, the work surface color temperature, and the light emitting surface luminance are shown. The melatonin radiant flux of direct light on the subject's face is changed from 400 to 900 in increments of 100, the color temperature of the illumination light on the work surface is changed from 3000K to 7000K in increments of 1000K, and the light emitting surface brightness of the light emitting unit is , Varied according to the color temperature of the illumination light.

  The biological rhythm adjustment effect during the day was evaluated in four stages: “high effect” (◎), “medium effect” (◯), “small effect” (Δ), and “no effect” (×). According to the experimental results, when the melatonin radiant flux was 700 and 800, the evaluation was “medium effect” (◯), and when the melatonin radiant flux was 900, the evaluation was “high effect” (◎). . That is, if the melatonin action radiant flux is set to 700 or more, the biological rhythm adjustment effect during the day can be obtained.

  The influence on the biological rhythm at night was evaluated in four stages: “no influence” (◎), “small influence” (◯), “medium influence” (Δ), and “high influence” (×). According to the experimental results, the evaluation was “small influence” (◯) when the work surface color temperatures were 5000K and 4000K, and the evaluation was “no effect” (◎) when the work surface color temperature was 3000K. That is, if the work surface color temperature is set to 5000K or less, the influence on the nighttime biological rhythm is small.

The subject's glare feeling was evaluated in three stages: “no glare feeling” (◯), “medium glare feeling” (Δ), and “large glare feeling” (×). According to the experimental results, the evaluation was “no glare” (◯) when the light emitting surface luminance was 18000 cd / m ² and 20000 cd / m ² . That is, when the luminance of the light emitting surface is set to 20000 cd / m ² or less, glare due to the lighting fixture is suppressed.

As described above, energy-saving task-and-ambient lighting is performed by the lighting fixture 1, and the irradiation effect of the circadian rhythm is adjusted in the first work time zone by changing the irradiation of light emitted by the lighting fixture 1 according to the time zone. As a result, since the influence on the circadian rhythm is reduced in the second work time zone, it is possible to achieve both energy saving and adjustment of the circadian rhythm. Further, since the average luminance of the light emitting unit that irradiates the face of the person who performs the work with direct light is set to a predetermined value (20000 cd / m ² ) or less, glare due to direct light can be suppressed.

The light emitting unit that irradiates the face of the person who performs the work with direct light may limit the light output of the light source to reduce the average luminance to 20000 cd / m ² or less, but the filter attenuates direct light outside the specific wavelength range. The average luminance may be set to 20000 cd / m ² or less.

  For example, as shown in FIG. 4, the light emitting unit 5 includes a light source 6 that irradiates direct light 51 </ b> L on the face of the user 4 and illumination light 52 </ b> L on the work surface 2, and a filter 7 that transmits light in a specific wavelength range. The face is irradiated with direct light 51L through the filter 7.

  As shown in FIG. 5, the light emitting unit 5 includes a face light emitting unit 51 having a light source 61 that emits direct light 51 </ b> L onto the face of the user 4, and a light source 62 that emits illumination light 52 </ b> L onto the work surface 2. A filter 7 that transmits light in a specific wavelength range is provided in the face light emitting unit 51, and the face is irradiated with direct light 51 </ b> L via the filter 7. Good.

  As shown in FIG. 6, the filter 7 is selected to have a high transmittance in a relatively short wavelength region and a low transmittance in a longer wavelength region out of the visible light wavelength region. Thereby, while maintaining the circadian rhythm adjustment effect by the direct light of a short wavelength, it can cut direct light other than a short wavelength, reduce average brightness, and can suppress glare.

(Second Embodiment)
A lighting apparatus according to a second embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 7, the luminaire 10 of the present embodiment includes a light emitting unit 5 that irradiates direct light on the user's face and illumination light on the work surface, and a first light control of the light emitting unit 5. A control unit 54, a support unit 3 that supports the light emitting unit 5 movably up and down, a movable unit 8 that moves the light emitting unit 5, a second control unit 81 that controls the movement of the light emitting unit 5, and a light emitting unit And a height detection unit 9 for detecting the height relative to the work surface.

  As shown in FIGS. 8 and 9, the light emitting unit 5 is a light source composed of a long lamp 53 that is long to the left and right toward the user 4 and a fluorescent lamp, LED, organic EL, or the like attached to the lamp 53. 6, and is configured as an integrated unit that serves as both a face light emitting unit that irradiates the user 4 with direct light and a work surface light emitting unit that irradiates the work surface 2 with illumination light. The first control unit 54 includes an inverter and the like, and adjusts the light output of the light source 6 to control the light emission unit 5 to be dimmed.

  The support unit 3 is, for example, a guide rail that is vertically attached to a partition 34 that is erected in the back position of the work surface 2, and supports the light emitting unit 5 movably up and down. The lamp 53 is suspended from a drum 83 attached to the upper part of the partition 34 by a rope 82 or a rope 82 or the like. The drum 83 is rotated by the motor 84, winds up the cord 82, raises the lamp 53 along the support part 3, and lowers the lamp 53 by rotating in reverse. The drums 83 are provided as a pair on the left and right sides of the partition 34, and their rotations are synchronized by a rotating shaft 85 that connects the drums 83. These motor 84, drum 83, rotating shaft 85, and rope 82 constitute the movable portion 8. The second control unit 81 controls the rotation and stop of the motor 84 to control the position of the light emitting unit 5 with respect to the work surface 2.

  The height detection unit 9 is a limit switch, for example, and is attached in the vicinity of the upper end and the lower end of the support unit 3 to detect that the light emitting unit 5 is in the upper position or the lower position. The upper position is set to a position higher than the line of sight of the user 4 who is seated, and the lower position is set to a position lower than the line of sight of the user 4 and higher than the work surface 2.

  The lighting fixture 10 configured as described above switches the presence or absence of direct light irradiation on the face of the user 4 by changing the position of the light emitting unit 5 with respect to the work surface 2. In a first work time period, for example, during the day, the light emitting unit 5 (shown by a solid line) is raised to a position (upper position) higher than the line of sight of the user 4 who is seated, and the face of the user 4 and the work surface 2. Irradiate light. In the second work time period, for example, from evening to night, the light emitting unit 5 (indicated by a two-dot chain line) is lowered to a position (lower position) lower than the line of sight of the user 4 who is seated, and on the face of the user 4 Only the work surface 2 is irradiated with no light. When the light emitting unit 5 is at the lower position, the light output of the light source 6 may be lowered by the first control unit 54 because the distance from the work surface 2 is short. By changing the height of the light emitting unit 5, while maintaining the illuminance of the work surface 2, the presence or absence of direct light on the face is switched, and the illuminance on the face is made variable. The raising and lowering of the light emitting unit 5 may be automatically controlled by a timer or the like, or may be manually operated.

  In this way, since the integrated light emitting unit 5 combines the direct light irradiation on the face and the illumination light irradiation on the work surface 2, the instrument configuration is simplified.

  Next, switching of the melatonin action radiant flux and color temperature of the light emitted by the light emitting unit 5 will be described. As shown in FIG. 10, the light source 6 of the light emitting unit 5 includes a high color temperature light source 61 and a low color temperature or white light source 62, for example, a plurality of high color temperature light sources 61 and a low color temperature or White light sources 62 are alternately arranged.

  In the first work time zone, the light emitting unit 5 turns on the high color temperature light source 61 and turns off the low color temperature or white light source 62 by the first control unit 54 and irradiates the light of the high color temperature. . In the second work time zone, the light emitting unit 5 turns on the low color temperature or white light source 62 and turns off the high color temperature light source 61 to emit low color temperature or white light. The light source 61 of the high color temperature and the light source of the low color temperature or white light source 62 may be switched on and off automatically by detecting the position of the light emitting unit 5 by the height detecting unit 9 or manually. Also good.

  As shown in FIG. 11, in the first work time zone, the light emitting unit 5 emits high color temperature light to the face of the user 4 and the work surface 2 from a position higher than the line of sight of the seated user 4. Irradiate. At this time, the direct light applied to the face has a melatonin action radiant flux of 700 or more per unit area of the vertical face. In the second work time zone, the light emitting unit 5 irradiates only the work surface 2 with low color temperature or white light from a position lower than the line of sight of the seated user 4. At this time, the illumination light applied to the work surface 2 has a color temperature of 5000K or less.

  The illumination light preferably has an average color rendering index (Ra) of 80 or more. Thereby, the visibility of the work surface can be maintained.

  In addition, as shown in FIG. 12, in the first work time zone, the light emitting unit 5 turns on both the high color temperature light source 61 and the low color temperature or white light source 62 so that the high color temperature and high illuminance are obtained. You may make it irradiate light. In the second work time zone, the light emitting unit 5 turns off the high color temperature light source 61 and turns on the low color temperature or white light source 62 to irradiate the low color temperature or white light.

  Further, as shown in FIG. 13, a light source 63 having a variable color temperature may be used for the light emitting unit 5, and the light output and the color temperature of the light source 63 may be controlled by the first control unit 54. In the first work time zone, in the light emitting unit 5, the light source 63 emits light of high color temperature. In the second work time zone, the same light source 63 emits low color temperature or white light. The light output of the light source 63 is lower in the second work time zone than in the first work time zone.

  The light source 63 with variable color temperature is a combination of red (R), green (G), and blue (B) light emitting diodes (LEDs) as shown in FIG. Irradiate light mixed with light. The color temperature of the light source 63 is variable by adjusting the light output of each of the RGB LEDs.

  As shown in FIG. 15, the light emitting unit 5 may be configured to change the irradiation range of the light source 6 according to the height from the work surface 2. The lamp 53 includes a reflection plate 55 that reflects light from the light source 6. When the light emitting unit 5 is lowered, the light emitting unit 5 rotates the lamp 53 or the reflecting plate 55 toward the user 4 side. This rotation is performed in conjunction with the vertically movable mechanism of the light emitting unit 5. For example, a rack gear is provided on the support unit 3 and a pinion gear is provided on the light emitting unit 5 (not shown), and the pinion gear is rotated by the vertical movement along the support unit 3 of the light emitting unit 5 and decelerated by the rotation. The reflecting plate 55 is rotated through the gear. Thereby, the unevenness of the brightness of the work surface 2 is reduced. Note that this rack and pinion may be used as a vertically movable mechanism of the light emitting unit 5.

  In addition, as shown in FIG. 16, instead of moving the light emitting unit 5 up and down, the lamp 53 or the reflecting plate 55 is rotated to switch the presence or absence of direct light irradiation on the face of the user 4. You may comprise. For example, in the first work time zone, the light emitting unit 5 irradiates the face of the user 4 and the work surface 2 with light from a position higher than the eyes of the seated user 4. In the second work time zone, the light emitting unit 5 rotates the reflector 55 in the direction of the work surface 2 by a motor or the like, and irradiates only the work surface 2 from the same position. In the control of this modification, an angle detector that detects the angle of the reflector is used instead of the height detector. Further, the light emitting unit 5 may be configured to project the reflecting plate 55 in the face direction of the user 4 instead of rotating the reflecting plate 55.

(Third embodiment)
A lighting apparatus according to a third embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 17 and FIG. 18, a plurality of desks 41 are arranged in the room, and the first lighting duct 56 and the second lighting duct 57 are located above the desk 41 by the support portion 35 that can be self-supporting. Is supported substantially horizontally. The desk surface of each desk 41 is a work surface. The first illumination duct 56 is supported at a position higher than the eyes of the seated user, and the second illumination duct 57 is supported at a position lower than the eyes of the seated user.

  In the first and second illumination ducts 56 and 57, the light source module 58 shown in FIG. 19B is detachably attached to the duct shown in FIG. The light source module 58 includes a light source 6 made of an LED or the like, and functions as a light emitting unit of the lighting fixture 11 in the present embodiment. In the first and second lighting ducts 56 and 57, a plurality of lighting fixtures 11 are arranged corresponding to each desk 41. The lighting fixture 11 arrange | positioned at the duct of the same system | strain is electrically fed from the duct of the system | strain. Note that a human sensor module 91 shown in FIG. 19C and a brightness sensor module 92 shown in FIG. 19D may be attached to the duct. The human sensor module 91 detects the presence or absence of a user, the brightness sensor module 92 detects the brightness of the work surface, and the detection results are used to control the lighting, dimming, and extinguishing of the light source module 58. It is done.

  Operation | movement of the lighting fixture 11 comprised as mentioned above is demonstrated. In the first work time zone, the light source module 58 disposed in the first illumination duct 56 irradiates the user's face and work surface with high color temperature light. The light irradiated at this time has a melatonin radiant flux of 700 or more per unit area of the vertical face. In the second work time zone, the light source module 58 disposed in the first illumination duct 56 is turned off, and the light source module 58 disposed in the second illumination duct 57 is positioned lower than the eyes of the seated user. Therefore, only the work surface is irradiated with light having a low color temperature. The light irradiated at this time has a color temperature of 5000K or less. The light source module 58 may automatically control lighting by performing addressing by, for example, PLC (power line communication).

  Accordingly, the lighting fixtures 11 can be easily increased or decreased by attaching and detaching the light source module 58, and the plurality of lighting fixtures 11 can be turned on and off collectively.

  The lighting fixture which concerns on the modification of this embodiment is demonstrated with reference to FIG. As shown in FIGS. 20 and 21, the support bar 36 that supports the plurality of first illumination ducts 59 and the second illumination duct 57 are substantially horizontally above the desk 41 by the support portion 35 that can stand on its own. Supported. The 1st illumination duct 59 is arrange | positioned for every desk 41, and is supported substantially horizontally in the position higher than the eyes | visual_axis of the seated user. The second illumination duct 57 is provided in common to the plurality of desks 41 and is supported at a position lower than the line of sight of the seated user.

  As shown in FIG. 22, each first illumination duct 59 is pivoted to the support bar 36 via the arm 38. One end of the arm 38 is detachably attached to the support bar 36, and can be rotated around the support bar 36 by a rotation mechanism 37. A first illumination duct 59 is attached to the other end of the arm 38, and the first illumination duct 59 is rotatable in parallel with the support bar 36. The first illumination duct 59 is supplied with power via the arm 38 and the support bar 36. Thus, the height of the first illumination duct 59 from the work surface is individually adjusted.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, in the second embodiment, the mechanism for moving the light emitting unit 5 up and down may be a link mechanism such as a cross link or a ball screw.

1, 10, 11 Task lighting device 5 Light emitting part 51 Light emitting part for face 52 Light emitting part for work surface 7 Filter 56, 57, 59 Duct

Claims (7)

A lighting method using a task lighting device for illuminating a work surface,
The time zone in which the task lighting device illuminates is divided into at least a first work time zone and a second work time zone,
The task lighting device irradiates the face of the person who performs the work with direct light in the first working time period, and the direct light suppresses the secretion of melatonin per unit area of the vertical face. The radiant flux of light is 700 W or more,
In the second working time zone, the illumination light by the task lighting device is characterized in that the direct illumination light is not applied to the face and the illumination light applied to the work surface has a color temperature of 5000K or less. The task lighting device includes a light emitting unit that irradiates the face with direct light,
The lighting method according to claim 1, wherein the light emitting unit has an average luminance of 20000 cd / m 2 or less. A task lighting device for illuminating a work surface,
The task lighting apparatus includes a light emitting unit for a face that irradiates the face of a person who performs the work with direct light, and a light emitting unit for the work surface that irradiates the work surface with illumination light.
The direct light has a radiant flux of 700 W or more for suppressing the secretion of melatonin per unit area of the vertical face of the face,
The task lighting apparatus according to claim 1, wherein the illumination light has a color temperature of 5000K or less.   The task lighting device according to claim 3, wherein the facial light emitting unit includes a filter that transmits light in a specific wavelength range, and irradiates the face with direct light through the filter. The light emitting unit for the face and the light emitting unit for the work surface are integrated light emitting units,
The task lighting apparatus according to claim 3, wherein the light emitting unit switches the presence / absence of direct light irradiation on the face by changing a position with respect to the work surface.   The task lighting device according to claim 3, wherein the plurality of task lighting devices are supplied with power from a duct of the same system.   The task lighting device according to claim 3, wherein an average color rendering index of illumination light is 80 or more.

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