Lighting control device, lighting control system, lighting control method, and lighting control program

Abstract

To provide a lighting control device, a lighting control system, a lighting control method, and a lighting control program that can improve lighting efficiency by taking in external light into a room even when direct sunlight is blocked. [Solution] The lighting control device 10 includes an acquisition unit 12 that acquires the slat angles of the blinds 30 adjusted to block direct sunlight 51 entering from an external light entrance unit 140 while allowing ground reflected light 52 to pass toward the ceiling 110 in a lighting control area 100 partitioned by a ceiling 110, a floor 120, and a wall 130, and measurement results of the brightness of at least one location on the ceiling 110; an estimation unit 14 that estimates the brightness distribution of the ceiling 110 based on the slat angles of the blinds 30 and the measurement results of the brightness of at least one location on the ceiling 110; and a control unit 16 that controls lighting devices 40 installed at at least one location on the ceiling 110 based on the estimated results of the brightness distribution of the ceiling 110.

Description

[Technical Field]

[0001] The present disclosure relates to a lighting control device, a lighting control system, a lighting control method, and a lighting control program. [Background technology]

[0002] Patent Document 1 describes a blind that controls the slat angle in accordance with the angle of incidence of sunlight to prevent direct sunlight from entering a room. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-74705 Summary of the Invention [Problem to be solved by the invention]

[0004] When direct sunlight does not enter a room, it is necessary to take in external light and increase lighting efficiency.

[0005] An object of the present disclosure is to provide a lighting control device, a lighting control system, a lighting control method, and a lighting control program that can improve lighting efficiency by allowing external light to enter a room even when direct sunlight is blocked. [Means for solving the problem]

[0006] A lighting control device according to an embodiment of the present disclosure includes an acquisition unit, an estimation unit, and a control unit. The acquisition unit acquires slat angles of blinds adjusted to block direct sunlight incident through external light incident units located on parts of the walls in a lighting control area partitioned by a ceiling, a floor, and walls while allowing surface-reflected light resulting from the direct sunlight or skylight being reflected by objects on the ground to pass toward the ceiling, as well as brightness measurements of at least one location on the ceiling. The estimation unit estimates a brightness distribution of the ceiling based on the slat angles of the blinds and the brightness measurements of the at least one location on the ceiling. The control unit controls lighting devices installed in at least one location on the ceiling based on the estimated brightness distribution of the ceiling.

[0007] A lighting control system according to an embodiment of the present disclosure includes a blind, a brightness measurement device, a lighting device, and a lighting control device. The slat angle of the blind is adjusted to block direct sunlight incident through the external light incident portion while allowing surface-reflected light, which is the direct sunlight or skylight reflected by an object on the ground, to pass toward the ceiling. The lighting control device includes an acquisition unit, an estimation unit, and a control unit. The acquisition unit acquires the slat angle from the blind and acquires a measurement result of brightness at at least one location on the ceiling from the brightness measurement device. The estimation unit estimates a brightness distribution on the ceiling based on the slat angle and the measurement result of brightness at at least one location on the ceiling. The control unit controls the lighting device based on the estimation result of the brightness distribution on the ceiling.

[0008] A lighting control method according to one embodiment of the present disclosure includes a lighting control device acquiring slat angles of blinds adjusted in a lighting control area partitioned by a ceiling, a floor, and a wall so as to block direct sunlight incident through an external light incident portion located on a portion of the wall while allowing surface-reflected light resulting from the direct sunlight or skylight being reflected by an object on the ground to pass toward the ceiling, and a measurement result of brightness of at least one location on the ceiling. The lighting control method also includes the lighting control device estimating a brightness distribution of the ceiling based on the slat angles of the blinds and the measurement result of brightness of the at least one location on the ceiling. The lighting control method also includes the lighting control device controlling lighting devices installed in at least one location on the ceiling based on the estimation result of the brightness distribution of the ceiling.

[0009] A lighting control program according to an embodiment of the present disclosure causes a processor to acquire slat angles of blinds adjusted in a lighting control area partitioned by a ceiling, a floor, and walls so as to block direct sunlight incident through an external light incident portion located on a portion of the wall while allowing surface reflected light resulting from the direct sunlight or skylight being reflected by an object on the ground to pass toward the ceiling, and brightness measurement results for at least one location on the ceiling. The lighting control program also causes the processor to estimate a brightness distribution on the ceiling based on the slat angles of the blinds and the brightness measurement results for at least one location on the ceiling. The lighting control program also causes the processor to control lighting devices installed at at least one location on the ceiling based on the estimated brightness distribution on the ceiling. [Effects of the Invention]

[0010] According to an embodiment of the lighting control device, lighting control system, lighting control method, and lighting control program of the present disclosure, external light can be introduced into a room even when direct sunlight is blocked, thereby improving lighting efficiency. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a block diagram illustrating an example configuration of a lighting control system according to the present disclosure. [Figure 2] FIG. 10 is a side view showing an example of the configuration of a lighting control area. [Figure 3] 10 is a schematic diagram showing an example of a range in which the ceiling of the lighting-controlled area is illuminated by ground-reflected light when the slat angle of the blinds is small. FIG. [Figure 4] 10 is a schematic diagram showing an example of a range in which the ceiling of the lighting-controlled area is illuminated by light reflected from features when the slat angle of the blinds is large. FIG. [Figure 5] 1 is a flowchart illustrating an example of a procedure for a lighting control method according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Configuration example of lighting control system 1) 1, a lighting control system 1 according to an embodiment of the present disclosure includes a lighting control device 10, a brightness measurement device 20, a blind 30, and a lighting device 40. The lighting control system 1 controls the brightness of a lighting control area 100 illustrated in FIG.

[0013] The lighting-controlled area 100 may include various spaces for which lighting is to be controlled, such as an office, a conference room, or a classroom. The lighting-controlled area 100 is a space partitioned by a ceiling 110, a floor 120, and a wall 130. The lighting-controlled area 100 also includes an external light entrance section 140 on a portion of the wall 130. The external light entrance section 140 allows external light, such as direct sunlight 51 from the sun 50, skylight, or ground-reflected light 52, to pass through into the lighting-controlled area 100. Skylight is sunlight scattered by particles in the air or clouds, and includes scattered light from the blue sky and scattered light from clouds. Ground-reflected light 52 is light resulting from the direct sunlight 151 from the sun 50 and skylight being reflected or scattered, including Lambertian surface diffuse reflection, by the ground 150 or objects on the ground surface. The ground 150 or objects on the ground surface are also referred to as ground features. The external light brightens the lighting control area 100. The external light entrance portion 140 may be a window, an opening, or the like.

[0014] When the sun 50 is blocked by clouds and almost no direct sunlight 151 is irradiated onto the object, the object is mainly irradiated with skylight. In this case, the light of the skylight reflected off the object may be considered as object-reflected light 52. Furthermore, when the object is sufficiently irradiated with direct sunlight 151, the object is irradiated with both direct sunlight 151 and skylight. In this case, the brightness of the direct sunlight 151 is much stronger than the brightness of the skylight. Therefore, the light of the direct sunlight 151 reflected off the object may be considered as object-reflected light 52.

[0015] <Lighting control device 10> As shown in FIG. 1, the lighting control device 10 includes an acquisition unit 12, an estimation unit 14, and a control unit 16.

[0016] The acquisition unit 12 acquires the measurement results of the brightness measuring device 20. It also acquires the slat angles of the blinds 30. The acquisition unit 12 may be configured to be able to communicate with the brightness measuring device 20, the blinds 30, etc. based on various communication standards such as a LAN (Local Area Network), RS-232C, or RS-485. The acquisition unit 12 may be configured to be able to communicate with the brightness measuring device 20, the blinds 30, etc. via a wired or wireless connection.

[0017] The estimation unit 14 estimates the brightness distribution on the ceiling 110 of the lighting-controlled area 100 due to the incidence of ground-reflected light 52, based on the measurement results of the brightness measurement device 20 and the slat angles of the blinds 30. The control unit 16 calculates the brightness to which the ceiling 110 contributes as a tertiary light source from the estimation result of the brightness distribution on the ceiling 110 of the lighting-controlled area 100, determines the intensity of the illumination light 60 to be emitted by the lighting device 40 in order to achieve the desired brightness in the lighting-controlled area 100, and controls the lighting device 40.

[0018] The estimation unit 14 or the control unit 16 may include at least one processor. The processor may execute a program that implements the functions of the estimation unit 14 or the control unit 16. The processor may be implemented as a single integrated circuit or a discrete circuit. The processor may be implemented as multiple communicatively connected integrated circuits or discrete circuits. The processor may also be implemented based on various other known technologies.

[0019] The lighting control device 10 may further include a memory unit. The memory unit may include, for example, an electromagnetic storage medium such as a magnetic disk, or may include a memory such as a semiconductor memory or a magnetic memory. The memory unit may store various information referenced in the operation of the estimation unit 14 or the control unit 16, and programs that implement various functions of the estimation unit 14 or the control unit 16. The memory unit may function as a work memory for the estimation unit 14 or the control unit 16. The memory unit may be configured integrally with the estimation unit 14 or the control unit 16, or may be configured separately from the estimation unit 14 or the control unit 16.

[0020] The control unit 16 outputs information for controlling the lighting device 40 to the lighting device 40. The control unit 16 may also output information for controlling the slat angles of the blinds 30 to the blinds 30. The control unit 16 may be configured to be able to communicate with the lighting device 40, the blinds 30, etc. based on various communication standards such as LAN, RS-232C, or RS-485. The control unit 16 may be configured to be able to communicate with the lighting device 40, the blinds 30, etc. via a wired or wireless connection. In the control unit 16, a portion that generates information for controlling the lighting device 40, the blinds 30, etc. and a portion that communicates with the lighting device 40, the blinds 30, etc. may be configured separately.

[0021] The acquisition unit 12, the estimation unit 14, and the control unit 16 may be configured integrally. The acquisition unit 12 and the estimation unit 14 may be configured integrally. The estimation unit 14 and the control unit 16 may be configured integrally.

[0022] The lighting control device 10 may further include an input device that accepts input of information, data, etc. from a user. The input device may include, for example, a touch panel or touch sensor, or a pointing device such as a mouse. The input device may include physical keys. The input device may include an audio input device such as a microphone. The lighting control device 10 may be configured to be connectable to an external input device.

[0023] The lighting control device 10 may further include an output device that outputs information, data, or the like to a user. The output device may include, for example, a display device that outputs visual information such as images, characters, or graphics. The display device may include, for example, a liquid crystal display (LCD), an organic electroluminescence (EL) display, an inorganic electroluminescence (EL) display, or a plasma display panel (PDP). The display device is not limited to these displays and may include various other display types. The display device may include a light-emitting device such as an LED (light-emitting diode) or an LD (laser diode). The display device may include various other devices. The output device may include, for example, an audio output device such as a speaker that outputs auditory information such as sound. The output device may include, for example, a vibration device such as a vibrator that outputs tactile information such as vibration. The output device is not limited to these examples and may include various other devices. The lighting control device 10 may be configured to be connectable to an external output device.

[0024] <Lighting device 40> The lighting device 40 is installed on the ceiling 110 of the lighting-controlled area 100 and emits illumination light 60. The illumination light 60 brightens the lighting-controlled area 100. The lighting device 40 includes various light sources, such as LEDs. The lighting device 40 may be configured as a glareless light. The lighting device 40 is not limited to a glareless light and may be configured in various other forms. The number of lighting devices 40 is not limited to one and may be two or more. When the number of lighting devices 40 is two or more, the on / off state of each lighting device 40 may be individually controlled by the lighting control device 10. Furthermore, the intensity of the illumination light 60 emitted by each lighting device 40 may be individually controlled by the lighting control device 10. The position of the lighting device 40 may be determined as appropriate.

[0025] <Brightness measuring device 20> The brightness measuring device 20 is installed on the ceiling 110 of the lighting control area 100 and measures the brightness of the ceiling 110 at the installation location. The greater the illuminance of light incident on a certain location, the greater the brightness of that location. The brightness measuring device 20 may be configured to include an illuminance sensor that measures the illuminance of the installation location. Illuminance is the amount of luminous flux incident on a unit area. The brightness measuring device 20 may measure the illuminance of the installation location as a physical quantity corresponding to the brightness of the ceiling 110 at the installation location. The brightness measuring device 20 is not limited to an illuminance sensor, and may be configured to include various sensors that can measure physical quantities corresponding to the brightness of the installation location. The number of brightness measuring devices 20 is not limited to one, but may be two or more. The position of the brightness measuring device 20 may be determined as appropriate.

[0026] <Blind 30> The blinds 30 are installed at a position through which external light entering the lighting-controlled area 100 from the external light entrance section 140 passes, and block or attenuate the external light entering the lighting-controlled area 100. In the present disclosure, the blinds 30 are located inside the external light entrance section 140 in the lighting-controlled area 100.

[0027] The blinds 30 have a plurality of slats 31 arranged in a direction from the ceiling 110 to the floor 120, i.e., along the vertical direction. The direction in which the slats 31 are arranged is not limited to the vertical direction and may be other directions. Each of the slats 31 extends in a direction intersecting the direction in which the slats 31 are arranged. In the present disclosure, the direction in which each of the slats 31 extends, i.e., the extension direction, is defined as a direction perpendicular to the vertical direction, i.e., the horizontal direction. Each of the slats 31 is defined as a thin, approximately rectangular plate whose longitudinal direction is the extension direction of the slat 31.

[0028] Each of the multiple slats 31 is configured to be rotatable around a rotation axis along the extension direction of the slat 31. The orientation of the slat 31 rotating around the rotation axis is determined by the slat angle. In the present disclosure, the slat angle is defined as the angle between the short side direction of the slat 31, which is perpendicular to the longitudinal direction of the slat 31, and the horizontal direction. Specifically, when the short side direction of the slat 31 coincides with the horizontal direction, the slat angle is 0 degrees. Furthermore, when the slat 31 rotates so that the inner end of the short side direction of the slat 31, i.e., the end farther from the external light incident section 140, is closer to the ceiling 110 than the outer end, i.e., the end closer to the external light incident section 140, the slat angle is defined as a positive value. For example, when the short side direction of the slat 31 coincides with the vertical direction and the slat 31 rotates so that the inner end of the short side direction of the slat 31 is closer to the ceiling 110, the slat angle is +90 degrees. In the present disclosure, all slats 31 of the blinds 30 are assumed to face the same direction. In other words, the blinds 30 are configured so that all slats 31 rotate at the same slat angle.

[0029] The width of the slat 31, i.e., the length of the slat 31 in the short direction, is set to a length that prevents gaps from forming between adjacent slats 31 when the blind 30 is viewed from the front when the slat angle is ±90 degrees.

[0030] The slats 31 may be configured to be rotated manually. The slats 31 may be configured to be rotated by power such as a motor. The blinds 30 may output the slat angle to the lighting control device 10 regardless of the means for rotating the slats 31. The slats 31 may be configured to rotate automatically to a slat angle instructed by the lighting control device 10. Even when the slats 31 rotate automatically based on the control of the lighting control device 10, the blinds 30 may output the slat angle to the lighting control device 10.

[0031] The brightness of the lighting-controlled area 100 is determined according to the intensity of light incident on the lighting-controlled area 100. When direct sunlight 51 enters the lighting-controlled area 100 from the external light incident section 140, the lighting-controlled area 100 becomes bright. However, if the lighting-controlled area 100 is too bright, it may become difficult to work in the lighting-controlled area 100.

[0032] Therefore, in the present disclosure, the slats 31 of the blinds 30 are adjusted so that direct sunlight 51 does not directly enter the lighting-controlled area 100. Specifically, the slats 31 are adjusted to a direction that does not create gaps between the slats 31 when viewed from the sun 50. For example, the orientation of the slats 31 may be adjusted so that the short side direction of the slats 31 is perpendicular to the direction of incidence of the direct sunlight 51. Because the direct sunlight 51 is parallel light from the sun 50, it can be easily blocked by adjusting the orientation of the slats 31 in one direction.

[0033] When the slats 31 of the blinds 30 are manually rotated, a person present in the lighting-controlled area 100 may check the incident direction of direct sunlight 51, i.e., the altitude of the sun 50, and adjust the orientation of the slats 31 so that the direct sunlight 51 does not enter the lighting-controlled area 100. When the lighting control device 10 controls the slats 31, the lighting control device 10 may acquire information about the altitude of the sun 50 using the acquisition unit 12, and determine the slat angle based on the altitude of the sun 50 using the control unit 16 so that the direct sunlight 51 does not enter the lighting-controlled area 100. The lighting control device 10 may acquire in advance the relationship between the altitude of the sun 50 and the date and time, and determine the slat angle by calculating the altitude of the sun 50 at the current time.

[0034] Even when the slats 31 of the blinds 30 are adjusted so that direct sunlight 51 does not directly enter the lighting-controlled area 100, ground-reflected light 52 may still enter the lighting-controlled area 100, as shown in Fig. 2. This is because the incident direction of the ground-reflected light 52 has a component in a direction from the ground 150 toward the sky. As described above, the ground-reflected light 52 is light that is direct sunlight 151 from the sun 50 and is reflected by the ground 150 or an object on the ground surface. The ground-reflected light 52 includes light that is specularly reflected from the ground 150 or an object on the ground surface, and light that is Lambertianly reflected from the direct sunlight 151 from the ground 150 or an object on the ground surface.

[0035] Because the incident direction of the feature reflected light 52 includes a component directed from the ground 150 toward the sky, the feature reflected light 52 is incident on the ceiling 110 of the lighting-controlled area 100. The feature reflected light 52 is reflected by the ceiling 110 and illuminates the interior of the lighting-controlled area 100. If the sun 50 is a primary light source, the feature reflected light 52, which is direct sunlight 151 reflected from the sun 50, corresponds to a secondary light source. Furthermore, the light of the feature reflected light 52 reflected by the ceiling 110 corresponds to a tertiary light source. The brightness inside the lighting-controlled area 100 is determined not only by the intensity of the illumination light 60 emitted by the lighting device 40, but also by the brightness of the light of the feature reflected light 52 reflected by the ceiling 110, i.e., the tertiary light source. In the present disclosure, the lighting control device 10 controls the intensity of the illumination light 60 emitted by the lighting device 40, taking into account the brightness of the light of the feature reflected light 52 reflected by the ceiling 110, i.e., the tertiary light source. By taking into account the brightness of the tertiary light source, lighting efficiency is improved.

[0036] The ground reflected light 52 is reflected by the ground 150 or objects on the ground surface, and passes through the external light incident section 140 from various directions before entering the ceiling 110. As a result, the brightness of the ceiling 110 when the ground reflected light 52 is incident on the ceiling 110, i.e., the brightness of the tertiary light source, has a distribution within the surface of the ceiling 110. In this disclosure, the ground reflectance coefficient is used to calculate the brightness distribution on the ceiling 110 due to the incidence of the ground reflected light 52. The ground reflectance coefficient is an index defined using the same concept as the daylight factor for skylight.

[0037] Skylight is sunlight scattered by particles in the air or clouds, and includes scattered light from the blue sky and scattered light from clouds. Skylight, like ground-reflected light 52, is a secondary light source of sunlight. The impact of skylight passing through the external light entrance 140 on the lighting-controlled area 100 is known to be expressed by the daylight factor. The daylight factor is a concept used in environmental engineering, a branch of architectural engineering, and is an index of the impact of skylight on an arbitrary indoor space, i.e., the lighting-controlled area 100 of the present disclosure. The daylight factor is calculated from the projected solid angle of the external light entrance 140 as seen from an arbitrary point indoors, i.e., an arbitrary point within the lighting-controlled area 100 of the present disclosure, assuming that the luminance of the entire sky is constant at any given time. When calculating the daylight factor, it is assumed that the blinds 30 are fully open and do not block or attenuate light passing through the external light entrance 140. In this case, the daylight factor is calculated based on the luminance of the entire sky and the shape and area of ​​the external light entrance 140. Then, once the brightness measurement results at any point in the lighting-controlled area 100 are obtained, the brightness distribution in the lighting-controlled area 100 due to sky light can be calculated from the daylight factor.

[0038] On the other hand, the feature reflectance rate is calculated from the projected solid angle of the external light incident portion 140 as seen from an arbitrary point in the lighting control area 100, i.e., an arbitrary point on the ceiling 110 in this disclosure, assuming that the luminance of the feature reflected light 52 is constant at any time regardless of the angle of incidence from the feature. Assuming that the blinds 30 are fully open, the feature reflectance rate is calculated based on the luminance of the feature reflected light 52 and the shape and area of ​​the external light incident portion 140. When the blinds 30 are adjusted to block direct sunlight 51, the feature reflectance rate is calculated based on the luminance of the feature reflected light 52, the shape and area of ​​the external light incident portion 140, the slat angle, and the width, i.e., the length in the short direction, of the slats 31. Then, once the lighting control device 10 obtains brightness measurement results for at least one location on the ceiling 110, it can calculate the brightness distribution on the ceiling 110 due to the incidence of the feature reflected light 52 from the measurement results and the feature reflectance rate.

[0039] For example, as shown in FIG. 3 , when the incident direction of direct sunlight 51 is close to vertical, the blinds 30 may be adjusted so that the minor axis direction of the slats 31 is close to horizontal, i.e., the slat angle is reduced. In this case, the feature-reflected light 52 enters the lighting control area 100 in a direction close to horizontal and reaches a range on the ceiling 110 far from the blinds 30, represented as the reach range 52A in FIG. 3 . Regardless of the location of the reference point within the reach range 52A, the ratio of brightness due to the incidence of the feature-reflected light 52 gradually decreases toward points farther from the external light incident section 140. In FIG. 3 , relatively bright points are represented by areas with low-density hatching within the reach range 52A. Note that, for convenience, the brightness within the reach range 52A is shown as gradually changing, but in reality, it changes continuously.

[0040] On the other hand, as shown in FIG. 4 , when the incident direction of direct sunlight 51 becomes closer to horizontal than in FIG. 3 , the blinds 30 may be adjusted so that the minor axis direction of the slats 31 becomes closer to vertical, i.e., the slat angle becomes larger. In this case, the feature-reflected light 52 enters the lighting control area 100 in a direction closer to vertical than in FIG. 3 and reaches only a range on the ceiling 110 closer to the blinds 30 than in FIG. 3 , represented as the reach range 52A in FIG. 4 . Regardless of the location of the reference point within the reach range 52A, the ratio of brightness due to the incidence of the feature-reflected light 52 decreases more rapidly than in FIG. 3 toward points farther from the external light incident section 140. In FIG. 4 , as in FIG. 3 , relatively bright points are represented as areas with low-density hatching within the reach range 52A. Also, in FIG. 4 , as in FIG. 3 , the brightness within the reach range 52A is shown as gradually varying for convenience, but in reality, it changes continuously.

[0041] 3 and 4, the brightness distribution of the ceiling 110 due to the incidence of the feature reflected light 52 may be expressed as being brighter the closer to the external light incident portion 140 and darker the farther away from the external light incident portion 140. The brightness of the ceiling 110 due to the incidence of the feature reflected light 52 may not monotonically darken the farther away from the external light incident portion 140. For example, a function that outputs the brightness of the ceiling 110 using the distance from the external light incident portion 140 as an argument may be a function that has a maximum value along the way, rather than a function that monotonically decreases as the distance increases.

[0042] As described above, the lighting control device 10 estimates the brightness distribution on the ceiling 110 due to the incidence of the ground feature reflected light 52, and controls the intensity of the illumination light 60 emitted by the lighting device 40 in consideration of the estimated brightness distribution on the ceiling 110 due to the incidence of the ground feature reflected light 52. Specifically, the lighting control device 10 may estimate the brightness of the lighting control area 100 resulting from the ceiling 110, on which the ground feature reflected light 52 is incident, functioning as a tertiary light source, based on the estimated value of the brightness distribution on the ceiling 110 due to the incidence of the ground feature reflected light 52. The lighting control device 10 may also estimate the brightness of the lighting control area 100 resulting from the ceiling 110, on which the ground feature reflected light 52 is incident, functioning as a tertiary light source, based further on the reflectance of the ceiling 110. The lighting control device 10 controls the intensity of the illumination light 60 emitted by the lighting device 40 so that the brightness of the lighting control area 100 becomes the desired brightness, taking into account an estimated value of the brightness of the lighting control area 100 caused by the ceiling 110 on which the feature reflected light 52 is incident functioning as a tertiary light source.

[0043] The brightness measuring device 20 may be installed at a position where the ground reflected light 52 is incident, regardless of the slat angle of the blinds 30, so that the brightness of the ceiling 110 due to the incidence of the ground reflected light 52 can be measured. When the brightness measuring device 20 is installed in at least two locations, the brightness measuring device 20 may be installed at at least two locations at different distances from the external light incident portion 140.

[0044] (Example of operation of lighting control system 1) The acquisition unit 12 of the lighting control device 10 acquires the measurement results of the brightness of the ceiling 110 due to the incidence of ground reflected light 52 at the location where the brightness measurement device 20 is installed, i.e., the measurement results of the brightness at at least one point on the ceiling 110. The acquisition unit 12 also acquires the slat angles of the blinds 30. If the control unit 16 of the lighting control device 10 controls the slat angles of the blinds 30, the acquisition unit 12 does not need to acquire the slat angles of the blinds 30.

[0045] The control unit 16 may control the slat angles of the blinds 30 so that direct sunlight 51 does not enter the lighting-controlled area 100. The control unit 16 may also control the slat angles of the blinds 30 so that the amount of feature-reflected light 52 entering the ceiling 110 increases, assuming that direct sunlight 51 does not enter the lighting-controlled area 100. The control unit 16 may also control the slat angles of the blinds 30 so that the brightness measurement result by the brightness measurement device 20 is maximized. The control unit 16 may also control the slat angles of the blinds 30 so that the feature-reflected light rate is maximized.

[0046] The estimation unit 14 of the lighting control device 10 calculates the feature reflectance based on the slat angle of the blinds 30. The estimation unit 14 may acquire a feature reflectance that has been calculated in advance so as to correspond to the slat angle of the blinds 30.

[0047] The estimation unit 14 estimates the brightness distribution of the ceiling 110 due to the incidence of the ground feature reflected light 52, based on the ground feature reflection rate and the measurement result of the brightness at least at one point on the ceiling 110.

[0048] The estimation unit 14 estimates the brightness at each point on the floor 120 of the lighting control area 100, which is caused by the ceiling 110 functioning as a tertiary light source due to the incidence of the ground feature reflected light 52, based on the estimation result of the brightness distribution on the ceiling 110 due to the incidence of the ground feature reflected light 52. The estimation unit 14 may estimate the brightness at each point on the floor 120, which is caused by the ceiling 110 functioning as a tertiary light source, by assuming that the ground feature reflected light 52 is Lambertian reflected at each point on the ceiling 110. The estimation unit 14 may estimate the brightness at each point on the floor 120 by taking into account the reflectance at each point on the ceiling 110.

[0049] The control unit 16 of the lighting control device 10 controls the lighting device 40 based on the estimated brightness at each point on the floor 120 resulting from the ceiling 110 functioning as a tertiary light source, as determined by the estimation unit 14.

[0050] The control unit 16 may set a brightness control target for each point on the floor 120 of the lighting-controlled area 100. The control unit 16 may set the brightness control target for each point on the floor 120 so as to uniformly distribute brightness on the floor 120. The control unit 16 may also set the brightness control target so as to brighten only a specific area on the floor 120.

[0051] The control unit 16 may determine the output of the lighting device 40 so that the difference between the brightness control target and the estimated value of brightness caused by the ceiling 110 functioning as a tertiary light source due to the incidence of the ground-reflected light 52 at each point on the floor 120 is compensated for by the brightness caused by the illumination light 60. The control unit 16 may calculate the intensity of the illumination light 60 that needs to be incident on each point on the floor 120 so that the sum of the estimated value of brightness caused by the ceiling 110 functioning as a tertiary light source due to the incidence of the ground-reflected light 52 at each point on the floor 120 and the brightness caused by the illumination light 60 matches the brightness control target.

[0052] The control unit 16 may determine the output of the lighting device 40 when the lighting device 40 is turned on. The output of the lighting device 40 may be expressed as the intensity of the illumination light 60 emitted from the lighting device 40. The output of the lighting device 40 may be expressed as the power input to the lighting device 40. The control unit 16 may control the on or off state of the lighting device 40. Controlling the lighting device 40 to the off state by the control unit 16 corresponds to setting the output of the lighting device 40 to zero.

[0053] The control unit 16 controls the lighting device 40 based on the determined output. In this way, even when the blinds 30 are blocking direct sunlight 51, which is the primary light source, the ceiling 110, on which the ground reflected light 52, which is the secondary light source, is incident, functions as a tertiary light source, thereby reducing the output of the lighting device 40. As a result, the lighting efficiency is improved.

[0054] <Example of lighting control procedure> The lighting control device 10 may execute a lighting control method including the steps of the flowchart illustrated in Fig. 5. The lighting control method may be realized as a lighting control program executed by a processor constituting the estimator 14 or the controller 16. The lighting control program may be stored on a non-transitory computer-readable medium.

[0055] The estimation unit 14 acquires the state of the blinds 30 (step S1). Specifically, the estimation unit 14 acquires the slat angles from the blinds 30 using the acquisition unit 12. When the control unit 16 controls the slat angles of the blinds 30, the estimation unit 14 may acquire the slat angles of the blinds 30 from the control unit 16 using the acquisition unit 12.

[0056] The estimation unit 14 acquires the brightness measurement result (step S2). Specifically, the estimation unit 14 acquires, via the acquisition unit 12, the brightness measurement result of the ceiling 110 at the location where the brightness measurement device 20 is installed from the brightness measurement device 20.

[0057] The estimation unit 14 estimates the brightness distribution of the ceiling 110 (step S3). Specifically, the estimation unit 14 calculates or acquires a feature reflection rate determined based on the slat angle of the blinds 30. The estimation unit 14 calculates an estimate of the brightness distribution of the ceiling 110 based on the feature reflection rate and the measurement results of the brightness of the ceiling 110 at the installation location of the brightness measurement device 20. Furthermore, based on the estimate of the brightness distribution of the ceiling 110, the estimation unit 14 calculates an estimate of the brightness at each point on the floor 120 of the lighting control area 100 caused by the ceiling 110 functioning as a tertiary light source.

[0058] The control unit 16 determines the output of the lighting device 40 (step S4). Specifically, the control unit 16 may acquire an estimated value of the brightness of the lighting control area 100 caused by the ceiling 110 functioning as a tertiary light source from the estimation unit 14, and determine the output of the lighting device 40 so as to compensate for the difference between the brightness control target and the estimated value of the brightness caused by the ceiling 110 functioning as a tertiary light source with the brightness caused by the illumination light 60.

[0059] The control unit 16 controls the illumination device 40 based on the output of the illumination device 40 determined in the procedure of step S4 (step S5). The illumination device 40 emits illumination light 60 at the output determined in the procedure of step S4. After executing the procedure of step S5, the control unit 16 ends the execution of the procedure of the flowchart in FIG.

[0060] (summary) As described above, the lighting control device 10 calculates an estimate of the luminance distribution on the ceiling 110 based on the brightness measurement results at at least one point on the ceiling 110 in the lighting control area 100 and the slat angle of the blinds 30, and can control the lighting devices 40 based on the estimate of the luminance distribution on the ceiling 110. In this way, even when the blinds 30 are adjusted to block direct sunlight 51, which is a primary light source, the lighting control device 10 can control the lighting devices 40 by taking into account the brightness of the ceiling 110 due to the incidence of ground reflected light 52, which is a secondary light source, as a tertiary light source. By taking ground reflected light 52 into account, the intensity of the illumination light 60 from the lighting devices 40 is reduced, resulting in improved lighting efficiency.

[0061] The drawings illustrating the embodiments of the present disclosure are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0062] Those skilled in the art may make various modifications and alterations to the contents of the present disclosure based on the present disclosure. Therefore, these modifications and alterations are within the scope of the present disclosure. For example, in each embodiment, each functional unit, each means, or each step may be added to other embodiments without logical inconsistency, or may be replaced with each functional unit, each means, or each step of other embodiments. Furthermore, in each embodiment, multiple functional units, each means, or each step may be combined into one or divided into separate units. Furthermore, the above-described embodiments of the present disclosure are not limited to faithful implementation of each described embodiment, but may also be implemented by combining features or omitting some features as appropriate.

[0063] In one embodiment, (1) a lighting control device includes: an acquisition unit that acquires slat angles of blinds adjusted to block direct sunlight incident from an external light incident portion located on a part of a wall in a lighting control area partitioned by a ceiling, a floor, and a wall while allowing surface reflected light resulting from the direct sunlight or skylight being reflected by an object on the ground to pass toward the ceiling; a measurement result of brightness at at least one location on the ceiling; an estimation unit that estimates the brightness distribution of the ceiling based on the slat angles of the blinds and the measurement result of brightness at at least one location on the ceiling; and a control unit that controls lighting devices installed at at least one location on the ceiling based on the estimation result of brightness distribution on the ceiling.

[0064] (2) In the lighting control device described in (1) above, the estimation unit may acquire a feature reflectance corresponding to the slat angle of the blind, and estimate the brightness distribution of the ceiling based on the feature reflectance and the measurement results of the brightness of at least one location on the ceiling.

[0065] In one embodiment, (3) a lighting control system includes: a blind having light-blocking slats installed at an external light incident portion located on a part of a wall in a lighting control area partitioned by a ceiling, a floor, and walls; a brightness measurement device installed at least one location on the ceiling; a lighting device installed at least one location on the ceiling; and a lighting control device. The slat angles of the blind are adjusted to block direct sunlight incident from the external light incident portion while allowing ground-reflected light, which is the direct sunlight or skylight reflected by an object on the ground, to pass toward the ceiling. The lighting control device includes an acquisition unit that acquires the slat angles from the blind and acquires a measurement result of brightness at at least one location on the ceiling from the brightness measurement device; an estimation unit that estimates a brightness distribution on the ceiling based on the slat angles and the measurement result of brightness at at least one location on the ceiling; and a control unit that controls the lighting device based on the estimation result of brightness distribution on the ceiling.

[0066] (4) In the lighting control system described in (3) above, the blind may be configured to adjust the slat angle based on control from the lighting control device. The acquisition unit may acquire the incident angle of direct sunlight. The control unit may control the slat angle of the blind based on the incident angle of direct sunlight.

[0067] (5) In the lighting control system described in (3) or (4) above, the control unit may control the slat angle of the blinds so that the brightness measurement result at at least one point on the ceiling is maximized.

[0068] (6) In the lighting control system described in (3) or (4) above, the estimation unit may acquire a feature reflectance corresponding to a slat angle of the blind, and estimate a brightness distribution of the ceiling based on the feature reflectance and a measurement result of brightness at at least one location on the ceiling. The control unit may control the slat angle of the blind so that the feature reflectance is maximized.

[0069] (7) In the lighting control system described in any one of (3) to (6) above, the brightness measuring device may be installed at a location closest to the external light incident portion within the range in which the feature reflected light enters the ceiling regardless of the slat angle of the blinds.

[0070] (8) In the lighting control system described in any one of (3) to (7) above, the brightness measuring device may be installed at least two locations on the ceiling at different distances from the external light incident portion.

[0071] In one embodiment, (9) a lighting control method includes a lighting control device acquiring slat angles of blinds adjusted to block direct sunlight entering from an external light entrance portion located on a part of a wall in a lighting control area partitioned by a ceiling, a floor, and a wall while allowing surface reflected light resulting from the direct sunlight or skylight being reflected by an object on the ground to pass toward the ceiling, and a measurement result of brightness at at least one location on the ceiling; the lighting control device estimating a brightness distribution on the ceiling based on the slat angles of the blinds and the measurement result of brightness at at least one location on the ceiling; and the lighting control device controlling a lighting device installed at at least one location on the ceiling based on the estimation result of the brightness distribution on the ceiling.

[0072] In one embodiment, (10) the lighting control program causes a processor to execute the following: acquire slat angles of blinds adjusted to block direct sunlight entering from an external light entrance portion located on a part of the wall in a lighting control area partitioned by a ceiling, a floor, and a wall while allowing surface reflected light resulting from the direct sunlight or skylight being reflected by objects on the ground to pass toward the ceiling; acquire brightness measurement results for at least one location on the ceiling; estimate a brightness distribution on the ceiling based on the slat angles of the blinds and the brightness measurement results for at least one location on the ceiling; and control lighting devices installed in at least one location on the ceiling based on the estimated brightness distribution on the ceiling. [Explanation of symbols]

[0073] 1. Lighting control system 10 lighting control device (12: acquisition unit, 14: estimation unit, 16: control unit) 20 Brightness measuring device 30 Blinds (31: Slats) 40 Lighting equipment 50 sun 51, 151 Direct sunlight 52 Reflected light from ground (52A: Reach range) 60 Illumination Light 100 Lighting control area (110: ceiling, 120: floor, 130: wall, 140: external light entrance area)

Claims

1. an acquisition unit that acquires the slat angles of blinds that are adjusted to block direct sunlight incident from an external light incident portion located on a part of the wall in a lighting control area partitioned by a ceiling, a floor, and a wall, while allowing ground reflected light that is the direct sunlight or skylight reflected by an object on the ground surface to pass toward the ceiling, and the brightness measurement results of at least one location on the ceiling; an estimation unit that estimates a brightness distribution of the ceiling based on a slat angle of the blind and a measurement result of brightness at at least one location on the ceiling; a control unit that controls a lighting device installed at at least one location on the ceiling based on the estimated result of the brightness distribution on the ceiling; A lighting control device comprising:

2. 2. The lighting control device according to claim 1, wherein the estimation unit acquires a feature reflectance corresponding to a slat angle of the blind, and estimates a brightness distribution of the ceiling based on the feature reflectance and a measurement result of brightness at at least one location on the ceiling.

3. a blind having slats for blocking light, the blind being installed at an external light incident portion located on a part of the wall in a lighting control area partitioned by a ceiling, a floor, and a wall; a brightness measuring device installed at at least one location on the ceiling; a lighting device installed at at least one location on the ceiling; Lighting control device Equipped with the slat angle of the blind is adjusted so as to block direct sunlight incident through the external light incident portion while allowing ground reflected light, which is the direct sunlight or skylight reflected by an object on the ground, to pass toward the ceiling; The lighting control device includes: an acquisition unit that acquires the slat angle from the blind and acquires a measurement result of brightness at at least one location on the ceiling from the brightness measurement device; an estimation unit that estimates a brightness distribution of the ceiling based on the slat angle and a measurement result of brightness at at least one location on the ceiling; a control unit that controls the lighting device based on the estimated result of the brightness distribution on the ceiling; A lighting control system comprising:

4. the blind is configured to adjust the slat angle based on control from the lighting control device; the acquisition unit acquires the incident angle of the direct sunlight; The lighting control system according to claim 3 , wherein the control unit controls a slat angle of the blind based on an incident angle of the direct sunlight.

5. The lighting control system according to claim 3 , wherein the control unit controls the slat angles of the blinds so that a measurement result of brightness at at least one point on the ceiling is maximized.

6. The estimation unit acquires a feature reflectance corresponding to a slat angle of the blind, and estimates a brightness distribution of the ceiling based on the feature reflectance and a measurement result of brightness at at least one point on the ceiling; The lighting control system according to claim 3 , wherein the control unit controls the slat angles of the blinds so that the feature reflectance is maximized.

7. 7. The lighting control system according to claim 3, wherein the brightness measuring device is installed at a location closest to the external light incident portion within the range in which the feature reflected light is incident on the ceiling regardless of the slat angle of the blind.

8. The lighting control system according to claim 3 , wherein the brightness measurement devices are installed at least at two locations on the ceiling at different distances from the external light incident portion.

9. a lighting control device that acquires a slat angle of a blind that is adjusted so as to block direct sunlight incident from an external light incident portion located on a part of the wall in a lighting control area partitioned by a ceiling, a floor, and a wall, while allowing ground-reflected light that is the direct sunlight or skylight reflected by an object on the ground surface to pass toward the ceiling, and a measurement result of brightness at at least one location on the ceiling; The lighting control device estimates a brightness distribution on the ceiling based on a slat angle of the blind and a measurement result of brightness at at least one point on the ceiling; the lighting control device controls a lighting device installed at at least one location on the ceiling based on the estimated result of the brightness distribution on the ceiling; A lighting control method comprising:

10. In a lighting control area partitioned by a ceiling, a floor, and a wall, a slat angle of a blind adjusted to block direct sunlight incident from an external light incident portion located on a part of the wall while allowing ground reflected light, which is the direct sunlight or skylight reflected by an object on the ground, to pass toward the ceiling, and a measurement result of brightness at at least one location on the ceiling are acquired; Estimating a brightness distribution on the ceiling based on the slat angle of the blind and the brightness measurement result of at least one location on the ceiling; controlling a lighting device installed at at least one location on the ceiling based on the estimated result of the brightness distribution on the ceiling; A lighting control program that causes a processor to execute the above.

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