JPH04222789A - Light screening device - Google Patents

Abstract

PURPOSE:To obtain a light screening device incapable of seeing the inside of a room of a building having an opening such as a window glass from the outside in the daytime and night-time. CONSTITUTION:A light screening device is constituted of an illumination 6 of which luminous intensity is higher in a region of specific wavelength than in a region of other wavelength and light transmissible members 2 arranged so as to receive light emitted from the illumination 6. As the light transmissible members 2, a glass plate coated with a wavelength selective multilayer film having lower light transmittance in a region of another wavelength than in the region of the specific wavelength is used.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a light shielding device consisting of a light-transmitting member and a light, in which the outside can be seen through the light-transmitting member from the side where the light is arranged, but the light-transmitting member is visible from the outside. Relating to devices through which it is not possible to see the side through which the illumination is arranged.

0002

2. Description of the Related Art There is a strong demand for privacy protection from the outside in spaces such as rooms in office buildings and living rooms in homes that have internal lighting and openings equipped with transparent materials such as window glass. In this regard, conventionally
A thin film of metal oxide, metal nitride, etc. is provided on the surface of the light-transmitting member to increase the reflectance of the light-transmitting member and reduce the transmittance at the same time, thereby reducing the visibility of the internal space from the outside. something is known. Furthermore, it is known that the glass as a whole is illuminated by additionally illuminating the edge surface of the glass, thereby reducing the visibility of the internal space from the outside.

0003

However, according to the former method, when the interior space is viewed from the outside and the exterior space is brighter than the interior space, such as during the daytime, as shown in FIG. Although the amount of reflected light from the surface of the member is large, the amount of transmitted light from the inside is small, and good privacy protection performance is obtained (Figure 10 (a)). However, the brightness of the external space at night is the same as that of the internal space If it is very small compared to , almost no light is reflected from the surface of the light-transmitting material, so only the light transmitted from inside is visible, and the privacy protection performance becomes very poor (Figure 10 ( b
)) There was a problem. On the other hand, according to the latter method,
Although privacy protection performance can be obtained regardless of the brightness of the outside space, there are problems in that additional lighting is required, resulting in extra running costs and extra space.

0004

[Means for Solving the Problems] The present invention provides an illumination device in which the emission intensity in a specific wavelength region is higher than the emission intensity in other than the specific wavelength region, and an illumination device arranged to receive the light emitted from the illumination device, The light shielding device includes a light-transmitting member whose transmittance for light in the specific wavelength range is lower than transmittance for light outside the specific wavelength range.

The light-transmitting member in the present invention may be one that controls transmittance by absorption of the light-transmitting member itself, but a substrate for maintaining mechanical strength and a wavelength selection layer on the substrate may be used. It is preferable to use an optical multilayer film provided with an optical multilayer film having a characteristic property from the viewpoint of ease of transmittance control. In addition to mechanical strength and optical properties, the base material of the light-transmitting member is required to have weather resistance, heat resistance, etc. depending on the intended use, and glass plates and plastic plates are preferably used. Further, the multilayer film having wavelength selectivity may be directly coated on a glass plate or a plastic plate, or a film coated with the multilayer film may be attached to the surface of the glass plate or plastic plate.

As the multilayer film for controlling the transmittance, known metal films, semiconductor films, and dielectric films can be used. However, when it is particularly desired to increase the amount of transmitted light, dielectric films that are transparent in the visible range can be used. membranes, semiconductor membranes are used. In this case, the transmittance is controlled using the interference effect of light. When it is desired to reduce the amount of transmitted light, metal films and semiconductor films that absorb in the visible region are preferably used. In this case, the transmittance is controlled using interference effects and absorption effects.

[0007] As the specific wavelength range in which the light intensity of the illumination is high, any one or a plurality of wavelength ranges in the visible light wavelength range can be used. In this case, if two or fewer wavelength regions are used, the illumination light is colored. On the other hand, 3
The three primary colors of light [red (wavelength 700-610 nm), green (wavelength 570-500 nm)
nm), bluish-violet (wavelength: 480 to 400 nm)], the illumination light becomes white, which is preferable. Further, the width of the specific wavelength region can be set arbitrarily, but if the width is too wide, the width of the wavelength region in which the transmittance of the light-transmitting member is low becomes wide, and the amount of transmitted light from the external space decreases. This reduction in the amount of transmitted light becomes greater when there are a plurality of specific wavelength regions. When there is one specific wavelength region, the width of the wavelength region is preferably 200 nm or less, when there are two, it is preferably 100 nm or less, and when there are three, the width of the wavelength region is 80 nm or less.

[0008] The above-mentioned illumination may be one in which the light source itself has a desired wavelength dependence of light intensity, but it is also possible to use a light source and an optical filter member having wavelength selectivity for controlling light intensity with respect to wavelength. This is preferable because it increases the degree of freedom in controlling the wavelength and intensity of light. Further, the light source itself may have a continuous spectrum or a bright line spectrum, and a fluorescent lamp or an incandescent lamp can be used.

[0009] The optical filter member may control the light intensity by absorption of the optical filter member itself, but a multilayer film having wavelength selectivity may be provided on the surface of the base to maintain mechanical strength. It is preferable that the light be a member that is made of aluminum from the viewpoint of wavelength selectivity of light and controllability of intensity.

[0010] The larger the ratio of the light intensity of the illumination is between the specific wavelength range and the other wavelength ranges, and the lower the transmittance of the light-transmitting member in the specific wavelength range, the more the illumination is transmitted from the transparent member side through the transparent member to the illumination side. The visibility when viewing the screen is reduced, and the privacy protection performance is therefore improved. The light intensity ratio of the specific wavelength range of illumination and other wavelength ranges is 1
0 or more, and the transmittance of the light-transmitting member in the specific wavelength region is preferably 5% or less from the viewpoint of privacy protection performance. Furthermore, privacy protection performance at night is ensured by ensuring that the light intensity ratio between the specific wavelength range of the lighting and other wavelength ranges is 10 or more, and the transmittance of the light-transmitting member in the specific wavelength range is 1% or less. Most preferred.

[0011] The larger the light transmittance of the light transmitting member in other wavelength ranges than the light transmittance of the specific wavelength range, the higher the visibility of the light transmitting member into the external space from the side where the illumination is arranged. will improve. It is preferable that the ratio of the light transmittance of the light transmitting member to the light transmittance of the specific wavelength range to the light transmittance of other wavelength ranges is 1/5 or less from the viewpoint of improving visibility into the external space.

0012

[Operation] In the apparatus of the present invention, the light emitted from the illumination has a high intensity in a specific wavelength range, and has a low intensity outside the specific wavelength range. Furthermore, the light transmittance of the transparent member is related to the wavelength characteristics of the light emitted from the illumination, and the light transmittance is small in the specific wavelength range, and the light transmittance is large in wavelengths other than the specific wavelength range. . Therefore, the amount of illumination light transmitted through the transparent member is reduced.

[0013]

[Example] A detailed explanation will be given below based on an example. Example 1 As shown in Fig. 1, the center of a room 3 with a width of 4 m, a depth of 4 m, and a height of 2.5 m, consisting of white walls 1 on three sides and the remaining one in contact with the external space through a transparent member 2. A lighting device 6 consisting of an incandescent light bulb 5 surrounded by an optical filter 4 was installed in the area. Here, the light-transmitting member 2 has a structure in which a dielectric multilayer film 2B is formed on a glass substrate 2A, and has spectral transmittance characteristics as shown in FIG. The optical filter 4 around the incandescent light bulb 5 has a structure in which a dielectric multilayer film is formed on a glass substrate. This optical filter 4 causes the illumination light to have a spectral radiant flux distribution as shown in FIG. Therefore, the illumination light is colored yellow-green.

When the incandescent light bulb in the outside space is turned off and the incandescent light bulb inside the room is turned on, the results of measuring the wavelength distribution of the incident light intensity at a point A in the room at a distance of 2 m from the light source and from the light source. Point B in external space at the same distance as this
FIG. 4 shows the results of measuring the wavelength distribution of the incident light intensity. This shows that even though the light source is at the same distance and the relationship with the wall is almost the same, the intensity of incident light in the outside space is very small compared to the intensity inside the room. It can be seen that almost no illumination light leaks to the outside. Actually in this state,
When I looked inside the room from the outside space with the naked eye, the condition inside the room was almost impossible to discern.

[0015]Furthermore, when the outside space was turned on while the incandescent light bulb inside the room was on, and the outside space was viewed with the naked eye from inside the room, it was possible to identify the outside state without any problem, although some coloring occurred. Ta. In addition, when looking into the interior of the room from the outside space with the naked eye in this state, only the portion directly illuminated by the light from the outside space could be identified, but the other portions were almost impossible to discern.

Embodiment 2 As shown in FIG. 1, a building with a width of 4 m and a depth of 4 m has white walls on three sides and the remaining one is in contact with the external space through a light-transmitting member.
Lighting consisting of an incandescent light bulb surrounded by an optical filter was installed in the center of a room with a height of 2.5 m. Here, the light-transmitting member has a structure in which a dielectric, a semiconductor, and a metal multilayer film are formed on a glass substrate, and has spectral transmittance characteristics as shown in FIG. 5. The optical filter surrounding an incandescent light bulb has a structure in which a dielectric multilayer film is formed on a glass substrate. Due to this optical filter, the illumination light has a spectral radiant flux distribution as shown in FIG. Therefore, the illumination light is colored yellow-green.

When the incandescent light bulb in the outside space is turned off and the incandescent light bulb inside the room is turned on, the results of measuring the wavelength distribution of the incident light intensity at point A in the room at a distance of 2 m from the light source and from the light source. Point B in external space at the same distance as this
FIG. 6 shows the results of measuring the wavelength distribution of the incident light intensity. This shows that even though the light source is at the same distance and the relationship with the wall is almost the same, the intensity of incident light in the outside space is extremely small compared to the intensity of the incident light inside the room. It can be seen that almost no illumination light leaks to the outside. When I actually looked inside the room from the outside space with the naked eye in this state, I found that
Conditions inside the room were completely unrecognizable.

On the other hand, when we turned on the lights in the outside space with the incandescent light bulbs inside the room on and looked at the outside space from inside the room, we found that it was colored and became a little dark, but it was still difficult to discern the state of the outside. It was possible without any problem. Also, when I looked inside the room from the outside space with the naked eye in this state, it was completely unrecognizable.

Embodiment 3 As shown in Fig. 1, a building with a width of 4 m and a depth of 4 m has white walls on three sides and the remaining one is in contact with the external space through a light-transmitting member.
Lighting consisting of an incandescent light bulb surrounded by an optical filter was installed in the center of a room with a height of 2.5 m. Here, the light-transmitting member has a structure in which a dielectric, a semiconductor, and a metal multilayer film are formed on a glass substrate, and has spectral transmittance characteristics as shown in FIG. The optical filter surrounding an incandescent light bulb has a structure in which a dielectric multilayer film is formed on a glass substrate. Due to this filter, the illumination light has a spectral radiant flux distribution as shown in FIG. Therefore, the illumination light is not colored.

When the incandescent light bulb in the outside space is turned off and the incandescent light bulb inside the room is turned on, the results of measuring the wavelength distribution of the incident light intensity at a point A in the room at a distance of 2 m from the light source and from the light source. Point B in external space at the same distance as this
FIG. 9 shows the results of measuring the wavelength distribution of the incident light intensity. This shows that even though the light source is at the same distance and the relationship with the wall is almost the same, the intensity of incident light in the outside space is extremely small compared to the intensity of the incident light inside the room. It can be seen that almost no illumination light leaks to the outside. When I actually looked inside the room from the outside space with the naked eye in this state, I could not discern the state inside the room at all.

[0021] On the other hand, when the outside space was turned on while the incandescent light bulb inside the room was on, and the outside space was looked at with the naked eye from inside the room, it was possible to discern the outside state without any problem, although it became somewhat dark. . Also, when I looked inside the room from the outside space with the naked eye, it was completely unrecognizable.

[0022]

Effects of the Invention: If the lighting of the device of the present invention is placed inside a room of a building and the translucent member is placed as a window member, the inside cannot be seen from the outside of the shared room during the day or at night. It can be a room with protected privacy.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the privacy protection lighting system of the present invention.

FIG. 2 is a diagram showing the light transmittance distribution of the transparent member used in Example 1 of the present invention.

FIG. 3 is a diagram showing the spectral radiant flux distribution of illumination light after passing through the optical filter used in Examples 1 and 2 of the present invention.

[Figure 4]
A diagram showing the wavelength distribution of incident light intensity measured at points A and B in Example 1 of the present invention

FIG. 5 is a diagram showing the light transmittance distribution of the transparent member used in Example 2 of the present invention.

FIG. 6 is a diagram showing the wavelength distribution of incident light intensity measured at points A and B in Example 2 of the present invention.

FIG. 7 is a diagram showing the light transmittance distribution of the transparent member used in Example 3 of the present invention.

FIG. 8 is a diagram showing the spectral radiant flux distribution of illumination light after passing through an optical filter, used in Example 3 of the present invention.

FIG. 9 is a diagram showing the wavelength distribution of incident light intensity measured at points A and B in Example 3 of the present invention.

[Figure 10] Diagram for explaining the magnitude relationship between transmitted light and reflected light during daytime and nighttime

[Explanation of symbols]

1 Wall 2 Translucent member 2A Glass plate 2B Multilayer film 3 Room 4 Optical filter 5 Incandescent light bulb 6. Lighting

Claims (3)

[Claims] 1. An illumination device whose emission intensity in a specific wavelength region is greater than the emission intensity in areas other than the specific wavelength region; and a light-transmitting member having a transmittance lower than that for light outside the specific wavelength range. 2. The light-transmitting member is a glass plate with a wavelength-selective multilayer film provided on its surface, and the illumination includes a light source and a wavelength-selective multilayer film provided to surround the light source. The light shielding device according to claim 1, comprising a coated optical filter member. 3. The light emission intensity of the specific wavelength region of the illumination is 10 times or more of the light emission intensity of wavelengths other than the specific wavelength, and the light transmittance of the light transmitting member in the specific wavelength region is 5. % or less
The light shielding device described in .