JP2020077484A - Dimming system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a lighting means of a light control film in consideration of visibility of the light control film according to a change in the installation environment (illuminance by a light source such as illumination light) of the light control film used for an indoor partition. Proposal of dimming system. SOLUTION: This is a dimming system used in an indoor space partitioned into a space A and a space B by a partition, and a light emitting means for illuminating the space in at least one of the partitioned space A and the space B. The partition has a dimming unit whose haze changes according to the applied voltage and an illuminance sensor, and the dimming unit under the illuminance condition based on the measurement result of the illuminance in the partition by the illuminance sensor. It is provided with a control device for controlling light emission by a light emitting means so that the apparent haze of the above can be seen as a preset haze. [Selection diagram] FIG. 6

Description

  The present invention relates to a light control system including a light control film.

  Light control films that switch between an opaque state (for example, a cloudy state) and a transparent state are used in various applications. For example, a light control film is provided with a light control layer made of a liquid crystal element using a liquid crystal material, held between electrodes, and the alignment state of liquid crystal molecules contained in the light control layer is changed by a voltage applied to the electrodes. The opaque state in which incident light is scattered and the transparent state in which incident light is transmitted can be switched. (For example, refer to Patent Document 1) The light control film is fixed to a transparent base material such as glass, so that it can be applied not only to buildings but also to windows of vehicles (railways, buses, ships, aircrafts), exhibition windows, partitions. It becomes possible to employ it for. For example, a light control film has been proposed as a product suitable for use as a sunroof for automobiles and a sun visor as well as equipment for separating the space, such as for separating a private space and a public space.

  A TN (Twisted Nematic) mode has been put into practical use as a liquid crystal element using a liquid crystal material. In this mode, light is switched by utilizing the optical rotation property of liquid crystal, and it is necessary to use a polarizing plate when using as a liquid crystal element. However, the use of the polarizing plate reduces the light utilization efficiency. As a liquid crystal element having a high light utilization efficiency without using a polarizing plate, there is a liquid crystal element that switches between a transmission state and a scattering state. As a liquid crystal element, generally, a polymer dispersed liquid crystal (PDLC) in which liquid crystal molecules are dispersed and arranged in a polymer, or a polymer network formed of a resin formed in a three-dimensional mesh shape is used. It is known to use a polymer network liquid crystal (PNLC) having liquid crystal molecules arranged in the formed voids. In both PDLC and PNLC, a part or the whole of a liquid crystal composition containing a polymerizable compound that is polymerized by ultraviolet rays exhibits liquid crystallinity. In the following description of the present invention, a light control film using PDLC or PNLC will be described.

As an application example of the light control film, various adjustments are made to keep the indoor illuminance optimal by controlling the light intensity of the indoor lighting equipment while adjusting the light incident from the outdoors to the indoor using the light control film. Dimming system is known. (For example, see Patent Documents 2 and 3)
Patent Document 2 is a proposal relating to a light control system that finely adjusts the ratio of direct light and diffused light that enter the room by a light control film, and adjusts the illuminance by illumination so as to keep the indoor brightness optimal. .. Patent Document 3 discloses an invention in which the outdoor sunshine is maximized, the power consumption of the lighting fixture is suppressed, and the indoor illuminance is kept optimal, in consideration of the indoor and outdoor illuminance difference (size). There is.

Japanese Patent No. 6348984 JP, 2011-40344, A JP, 2018-18727, A

When the light control film is used as an indoor space partition (space division), it can be recognized from the inside divided by the light control film depending on the brightness, angle, and distance of the illumination light from the outside to the light control film. It has been confirmed that the visibility changes according to the driving of the light control film. That is, even if the haze of the light control film is high and it is expected that the light control film will block the landscape or image in the back of the light control film, the light control film can be used in the landscape or the image in the back of the light control film depending on the use environment. May be transparent. In situations where indoor lighting equipment is used, the light rays that are received by the light control film surface and are detected as a factor indicating the illuminance on the light control film surface include not only the direct incident light from the lighting equipment but also the floor surface and side wall surface. The light reflected from the light incident on the light control film surface is also included. In the present invention, the illuminance on the light control film surface measured by the illuminance sensor installed on the light control film, and the apparent haze that the light control film presents at that time depending on the measured illuminance value (hereinafter, , Referred to as opacity). Visibility refers to the property of obstructing the field of view. When the light control film has low visibility, the back of the light control film can be seen through when viewed from the front of the light control film.When the light control film has high visibility, the light control film is adjusted from the front side of the light control film. I can't see the back of the optical film.

It has been empirically and experimentally confirmed that even with a light control film to which the same voltage is applied and the same haze, the visibility is different as follows depending on the installation environment (lighting conditions). In the following description, the term "illuminance on the light control film surface (unit: lx) ”is used.
(1) In an environment in which the luminaire is bright and the illuminance on the light control film surface is high, the light control film has a higher visibility than an environment in which the illuminance on the light control film surface is low. This is the same when viewed from either side of the partition by the light control film.
(2) The lighting device is not far from the light control film surface and is in a close range, and the light control film surface is closer to the front direction (direction perpendicular to the film surface) rather than obliquely. In this case, the illuminance becomes high, and the light-shielding film has a higher visibility.

  An object of the present invention is to propose a light control system capable of controlling the visibility of a light control film used for partitioning indoors.

  The light control system according to the present invention uses a lighting fixture, a light control film, an illuminance sensor that measures the illuminance on at least one surface of the light control film, and the illuminance measured by the illuminance sensor. And a control device that performs control. The light control film includes a transparent electrode layer supported by a pair of film base materials, and a light control layer sandwiched between the transparent electrode layers, and the light control layer contains liquid crystal molecules.

  As a method of controlling the lighting equipment, a method of changing the intensity of light emitted from the lighting equipment, a method of changing the positional relationship between the light control film and the lighting equipment, or the like is used alone or in an appropriate combination.

  In the light control system according to the present invention, the light control layer includes either a polymer network liquid crystal or a polymer dispersed liquid crystal.

  According to the present invention, it is possible to control the visibility of a light control film used for partitioning indoors.

The figure which shows notionally the structure of the light control system by this invention. The figure which shows the structure of a light control film. The block diagram which shows the function structure of a light control film control apparatus. The photograph which shows that the visual recognition state of the light control film changes with a specific applied voltage with the change of illumination conditions. Explanatory drawing which shows the usage example of a light control system. Explanatory drawing which shows operation | movement of a lighting fixture. The flowchart which shows the control procedure of the lighting fixture by a light control system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following description.

<Dimming system>
As conceptually shown in the embodiment of FIG. 1, the light control system includes a partition 10 having a light control film, a lighting device 20, an illuminance sensor 30, and a control device 40.

  Although the luminaire 20 and the illuminance sensor 30 are illustrated on both the space A side and the space B side partitioned by the partition 10 having the light control film, they do not need to be provided on both sides, but may be provided on at least one side. I wish I had it. In the figure, the lighting fixtures and illuminance sensors on the space A side are shown as 21, 31 and the space B side is shown as 22, 32.

  The partition 10 is formed by disposing a light control film on the surface of a transparent member having rigidity. Alternatively, the partition 10 includes a light control film sandwiched between a pair of transparent members. The light control film exhibits a transparent / scattering state change according to ON / OFF of the drive voltage, but the partition 10 as a whole maintains the translucency regardless of the ON / OFF of the drive voltage and is partitioned. The illumination lights from the luminaires 21 and 22 are not completely blocked by the partition 10 between the spaces A and B, and the other illumination lights are captured in the spaces A and B to influence the illuminance on the light control film surface. Affect each other.

  The lighting fixture 20 is often arranged on the ceiling of the interior of the building, but may be arranged on the side wall surface or the floor surface. The luminaire 20 emits illumination light indoors to ensure indoor brightness. The illuminance sensor 30 is provided at a predetermined portion of the partition 10 and measures the illuminance on the light control film surface on at least either side of the space A or the space B. The control device 40 controls the lighting fixture 20 by using the illuminance information input from the illuminance sensor 30 to control the light-shielding film so that the light-shielding property is set to a preset level.

<Light control film>
FIG. 2 is an explanatory view showing a structural example of the light control film 100 which is a main part of the partition 10.

  As the film base material 11 constituting the transparent electrode film 15, any substantially transparent flexible film base material suitable for roll-to-roll manufacturing can be used. Specifically, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate resins, acrylic resins, cellulose derivatives such as triacetyl cellulose (TAC), polyether sulfone (PES) resins, Examples of the film include polyimide resin and polyolefin resin such as polyethylene and polypropylene, but the film is not limited thereto. Further, the film base material 11 is not necessarily required to be flexible, and a sheet-shaped transparent base material having rigidity can also be adopted. In the case of a rigid sheet-shaped transparent substrate, a single-wafer manufacturing process is adopted instead of the roll-to-roll manufacturing.

  An ultraviolet absorber, a stabilizer, etc. may be added to the film substrate 11, and an ultraviolet absorbing layer, a heat ray reflecting layer, a barrier layer, etc. may be provided on any surface of the transparent film. But there is no problem. Further, the transparent film may be appropriately subjected to an easy-adhesion treatment, an antistatic treatment, or the like, and may further be provided with a reinforcing base material without any problem.

  As the transparent electrode 12, any conventionally known transparent electrode material can be used, and it is composed of an indium tin oxide (ITO) conductive film, a tin oxide conductive film, a zinc oxide conductive film, a polymer conductive film, or the like. The electrodes can be exemplified, but the electrodes are not necessarily limited thereto. The transparent electrode 12 can be formed by using a physical vapor deposition method (PVD method) such as a vacuum deposition method or a sputtering method, various chemical vapor deposition methods (CVD method), various coating methods, or the like. When the patterning of the transparent electrode 12 is required, it can be performed by any method such as an etching method, a lift-off method, a laser trimming method, and a method using various masks.

  An alignment film or the like may be appropriately provided between the transparent electrode 12 and the light control layer 13 as necessary. In the present invention, any type of liquid crystal composition, PDLC or PNLC, can be used as the light control layer 13, but hereinafter, PNLC will be described.

  There are two types of the light control layer 13, a normal type and a reverse type, depending on the use mode. The normal type is a type in which a voltage is applied (ON) to be in a transmissive state and a voltage is removed (OFF) to be in a scattering state. The reverse type is a type in which a voltage is removed (OFF) to be in a transmissive state and a voltage is applied (ON) to be in a scattering state. In the reverse type, since a liquid crystal is vertically aligned and is in a transmissive state when no voltage is applied, a liquid crystal alignment layer that vertically aligns the liquid crystal is used. In the case of the reverse type, the transparent conductive film 15 having the alignment film formed on the transparent electrode 12 is required.

  The production of the light control film having the light control layer by the reverse type PNLC is generally performed as follows. That is, first, a mixture of liquid crystal and a photopolymerizable compound (monomer) is sandwiched between a pair of transparent conductive films 15 (formed by laminating a transparent electrode and an alignment layer). Then, the photopolymerizable compound in the liquid crystal is converted into a polymer by photopolymerization by irradiating with ultraviolet light under a certain condition. By photopolymerization and cross-linking, a polymer network having innumerable fine domains (polymer voids) is formed in the liquid crystal. In the case of producing a light control film by normal type PNLC, a transparent conductive film 15 having a transparent electrode and an alignment layer laminated is used instead of the transparent conductive film 15 having a transparent electrode and an alignment layer laminated. It is done by the same procedure.

  The light control layer 13 (liquid crystal element) exhibits a behavior in which the polymer network and the liquid crystal region are clearly separated with high purity. Further, it is possible to realize an ideal alignment state without performing the pretilt alignment treatment by rubbing the transparent conductive film 15, and the liquid crystal molecules are aligned almost uniformly in each domain divided by the polymer network. become.

  The size of the PNLC domain is as small as about 1 μm, Rayleigh scattering (wavelength selective scattering) is not caused, and scattering in a wide wavelength range including at least the visible light region wavelength (400 to 780 nm) is efficiently generated.

  The drive voltage of the PNLC generally depends on the structural characteristics of the polymer network (domain size and shape, film thickness of the polymer network, etc.). In order to construct a PNLC capable of obtaining a sufficient degree of light transmission and scattering in a voltage region of 100 V or less, each domain has an appropriate size and is uniform and has a uniform shape. Therefore, it is necessary to form a polymer network. In the present invention, the domain size of the polymer network is controlled to 3 μm or less, preferably 2 μm or less, and more preferably about 1 μm.

  The power supply electrode 110 to the light control film 100 is on the transparent electrode 12 exposed by cutting one transparent conductive film 15 (half cut for the entire light control film 100) and removing the cut transparent conductive film 15. A lead wire (wiring) that has a connection part composed of a silver paste applied to the above and a copper tape attached to the upper side of the silver paste, and is supplied with power from an external power source (not shown) by the solder formed on the connection part. Is fixed. (In the figure, the silver paste and copper tape are shown in a simplified manner.)

<Change of opacity by illuminance>
In the light control system according to the present invention, the operating condition of the lighting fixture is changed to modulate the visibility of the light control film.

  In the prior arts illustrated in Patent Documents 2 and 3, the haze control by modulating the drive voltage of the light control film captures outside light (outdoor light such as sunlight) and the effective illumination light from indoor lighting equipment. The purpose of the present invention is to contribute to utilization (suppression of leakage to the outdoors), but the present invention changes the haze of the light control film 100 by modulating the irradiation amount (intensity) of the illumination light to the light control film 100. The light-shielding film 100 controls the light-shielding property of the light-controlling film 100.

  FIG. 3 is a block diagram showing a functional configuration of the control device 40. Based on the illuminance measured by the illuminance sensor 30, the illumination condition (irradiation distance, irradiation angle, etc.) for determining the illuminance for realizing the light-shielding property required for the light control film is V Calculation is performed by a central processing unit (CPU) that holds data related to the -T curve (described later). The driver changes the lighting condition of the lighting fixture 20 for the light control film 100 based on the lighting condition calculated by the CPU.

  The effect of irradiation of light on the light control film 100 on the visibility of the light control film will be described with reference to FIG. Here, the space on the side where the viewer is present is A, and the space on the other side is B. FIG. 4 shows a change in the external appearance of the light control film 100 driven by a specific applied voltage as seen from the space A side when the light emitting state of the lighting fixture installed in the space B is changed. The illuminance on the surface of the light control film is (a) 20, (b) 55, (c) 112, (d) 224, (e) 480, and (f) 1300 (unit: lx), respectively. Although the voltage applied to the light control film 100 is the same and the haze of the light control film 100 is the same, the appearance is (a) to (b), (c), (d) in terms of appearance. , (E), (f). In addition to the above lighting equipment, when a liquid crystal display is placed on the floor of the space B, under the low illuminance conditions of (a) and (b), the display image of the liquid crystal display is transparent to the light control film from the space A side. It was confirmed that the image was relatively clear and that the images displayed on the liquid crystal display could not be clearly seen from the space A side under the high illuminance conditions of (e) and (f).

  In this way, the occlusivity of the light control film also changes by modulating the illuminance on the surface of the light control film. In the light control system according to the present invention, the illuminance on the light control film surface is measured, and control is performed to change the operation of the lighting fixture 20 that irradiates the light control film surface according to the measured illuminance.

  FIG. 5 is a diagram showing an application example of the light control system. There is one person in one of the indoor spaces A (for example, aisle) and a plurality of people in the other space B (for example, a conference room). From the viewpoint of the space A, when the illumination in the space B is dark and the illuminance in the light control film is low, even if the haze of the light control film 100 is high, the light control film 100 has low visibility and the interior can be seen through. .. Depending on the see-through condition, the person in the space B is clearly discriminated from the space A side (upper left in FIG. 5). When the lighting fixture 20 in the space B is turned on to make the light brighter, the illuminance on the surface of the light control film is increased, the visibility of the light control film 100 is increased, and the space B side cannot be seen through from the space A side. The person in is not distinguished from the person in space A (upper right in FIG. 5). From the viewpoint of the space B, when the illumination in the space B is dark and the illuminance in the light control film is low, even if the haze of the light control film 100 is high, the light control film 100 has low visibility and the space A is transparent. Can be seen (bottom left of Fig. 5). When the lighting device 20 in the space B is turned on to brighten the illumination in the space B to increase the illuminance in the light control film, the light-shielding property of the light control film 100 is increased, and the space A side can be seen through from the space B side. There is no (Fig. 5, lower right).

  In the block diagram of FIG. 3, based on the illuminance on the light control film surface measured by the illuminance sensor 30, the difference between the target value and the measured value of the illuminance for realizing the light-shielding property required for the light control film 100. Is calculated by the CPU by comparison with the VT curve data (characteristic curve between the transmittance of the liquid crystal display element and the applied voltage) provided in the memory. The driver applies an electric signal applied from the drive power source (not shown) to the lighting fixture 20 in the space B or a drive system motor used to move or rotate the lighting fixture 20 based on the increase or decrease in illuminance calculated by the CPU. A program for changing an electric signal to be performed is provided. When an LED (Light Emitting Diode) lighting is used as an example of the lighting fixture 20, the LED lighting is not provided with a constant current circuit for keeping the light amount constant, and then the driver supplies the LED lighting. It is preferable to control the direct current. At this time, the driver continuously changes the magnitude of the direct current supplied to the lighting fixture 20 by using, for example, PWM (Pulse-Width Modulation) control.

  FIG. 6 is a diagram showing various driving examples of the lighting fixture 20. The lighting environment in which the light control film 100 is placed can be changed by the irradiation angle and the irradiation distance from the lighting fixture 20. It is changed by moving or rotating the lighting fixture 20 on the rail. In addition, the lighting environment in which the light control film 100 is placed is also changed by the selection of the light source and the control of the emission intensity of each when the lighting fixture includes a plurality of light sources. These are realized by determining the operation of the luminaire 20 according to an instruction from the driver to the drive system motor shown in the block diagram of FIG. 3 based on the illuminance difference calculated by the CPU. To determine the operation of the light source, select the optimum method from the combination of various parameters (irradiation distance, irradiation angle, emission intensity, light source selection) that exist to realize the calculated illuminance (target value). become.

  FIG. 7 shows a flow of control of illuminance modulation by the light control system. First, the illuminance sensor 30 acquires the illuminance on the light control film 100, and compares the acquired illuminance with a preset target value of the illuminance. Then, when the illuminance on the light control film 100 is lower than the target value of the illuminance, the illumination intensity by the luminaire is increased. The illumination intensity is changed by changing the light emission intensity of the lighting fixture, the position, the irradiation angle, or the like. The selection of the combination of the emission intensity, position, and irradiation angle of the lighting fixture is appropriately selected according to the lighting fixture included in the light control system. After increasing the illumination intensity of the luminaire, it is determined whether the illuminance on the light control film 100 matches the target value of the illuminance. Even if the illumination intensity of the lighting fixture is increased, if the illuminance on the light control film 100 does not match the target value of the illuminance, the process is returned to the illuminance detection.

  The memory of the light control system uses, as initial information related to the basic specifications of the light control film 100, VT curve data regarding a plurality of states (for example, three states of transparent = minimum haze, halftone haze, and scattering = maximum haze). , And as the test data obtained in advance, the data of the light-shielding property of the light control film 100 under various illuminance conditions is held. In the CPU, by using the illuminance information input from the illuminance sensor 30, the target hiding property is exhibited by comparing the haze (diffuse transmittance) of the light control film 100 with the hiding property according to the illuminance condition. In addition, the difference between the illuminance required for the light control film 100 and the illuminance input from the illuminance sensor 30 is acquired, and based on the acquired illuminance difference, the increase or decrease of the illumination intensity required for the light control film 100 is calculated. To do.

As described above, in a light control film used for partitioning indoors, a light control system capable of controlling the visibility of the light control film by controlling the illumination environment outside the light control film is provided. be able to. The four types of lighting environment control shown in FIG. 6 operate the luminaire provided in the space where the viewer is not present. It may work. Further, the present system is not limited to the case where the light control film 100 has a lower visibility than that expected from the actual haze of the light control film 100, and is visible from the actual haze of the light control film 100. It can also be used when the light control film 100 has a high shielding property and looks cloudy.

10 Partition 20 (21, 22) Lighting Equipment 30 (31, 32) Illuminance Sensor 40 Control Device 100 Light Control Film 15 Transparent Electrode Film 11 Film Base Material 12 Transparent Electrode 13 Light Control Layer 110 Power Supply Electrode

Claims (4)

A dimming system used for partitioning,
Lighting equipment,
Light control film,
An illuminance sensor that measures the illuminance on at least one surface of the light control film,
Using the illuminance measured by the illuminance sensor, a control device for controlling the lighting fixture,
The light control film, a transparent electrode layer supported by a pair of film bases, and a light control layer sandwiched between the transparent electrode layer,
A light control system, wherein the light control layer comprises liquid crystal molecules.   The dimming system according to claim 1, wherein the method of controlling the luminaire includes changing an intensity of light emitted by the luminaire.   The light control system according to claim 1 or 2, wherein a method of controlling the lighting fixture includes changing a positional relationship between the light control film and the lighting fixture.   The light control system according to claim 1, wherein the light control layer includes any one of a polymer network type liquid crystal and a polymer dispersion type liquid crystal.