JPH09281455A - Magnetic fluid light control device and lighting fixture with light control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to execute the light control of particularly the discharge lamp among lighting fixtures of a large capacity used in a theater, motion picture studio, television studio, etc., in the state of producing less light control sounds or the entirely absent state of these sounds if possible and to execute the light control at a high light control speed and analogically in multiple stages (or fine stages). SOLUTION: This lighting fixture has a magnetic fluid film 1, a pair of polarizing plates 2a, 2b which are arranged on the entire surface of the film and the rear surface thereof across the film plane of the magnetic fluid film and vary in the polarization directions from each other, means 3a, 3b for impressing magnetic fields in parallel with the film plane of the magnetic fluid film and a means 7 for controlling the magnitude of the magnetic fields by noticing the cotton mouton effect that the quantity of the light passing a pair of the polarizing plates across the magnetic fluid film changes with the magnitude of the magnetic fields impressed on the magnetic fluid film. The quantity of the light perpendicularly passing the magnetic fluid film plane is variably adjusted by controlling the magnitude of the magnetic fields.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical shutter used as lighting for a production space, and a lighting device for adjusting light by an electronic circuit having a semiconductor, for example, used in a theater, a movie studio, a television studio or the like. The present invention relates to a large-capacity lighting fixture, particularly a discharge lamp lighting fixture, in which a dimming sound, a dimming operation time, and a size of the fixture are improved, and a lighting fixture including the dimming device.

[0002]

2. Description of the Related Art The dimming of a conventional luminaire is an electronic circuit system in which the light emission amount is made variable by controlling a lamp current by using a transistor, or mechanical adjustment while the light emission amount remains unchanged. It is roughly classified into two methods, that is, a method of adjusting the amount of passing light by blocking light using a different shutter. In an electronic circuit type dimmer using a transistor, there is a problem that electromagnetic waves generated due to intermittent operation of current infiltrate into an electronic circuit of audio / video equipment and cause troubles such as noise generation or waveform distortion. It has been pointed out.

In particular, dimming in the emission frequency range of a discharge lamp is
Since it is difficult for an electronic circuit type dimmer using a transistor, a mechanical shutter type dimmer is often used.
For this reason, there are problems that the dimming sound is a major obstacle and that the time required for dimming (changing the amount of light) is long. Moreover,
It is also inconvenient that the variable range of dimming can be performed only at a rough stage.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a lighting fixture, in particular, a discharge lamp, which can be dimmed in a state with little dimming sound or, if possible, in a state where there is no dimming sound. It is an object of the present invention to increase the speed of light and enable analog multi-step (or fine) and miniaturization.

[0005]

The present invention focuses on the magneto-optical effect exhibited by a magnetic fluid and proposes to utilize the effect as a shutter means.

A magnetic fluid is a magnetic liquid that was invented by Papel of the National Aeronautics and Space Administration (NASA) in the 1960s. A magnetic fluid is a magnetic substance, and has the same characteristics as an ordinary magnetic substance. inside that,
The magneto-optical effect is used in the present invention. The magneto-optical effect of a magnetic material generally means that the optical characteristics are changed by applying a magnetic field to the magnetic material.

Ferrofluids have the property of reacting (attracting) to a magnetic field, and for water-based ferrofluids the magneto-optical effect (in this case linearly polarized light is split into two waves of horizontal and vertical components). At this time, the phase difference produced between two waves by applying a magnetic field is about 10 ⁸ times that of nitrobenzene, which is said to be large, and it is known that the magneto-optical effect of the magnetic fluid is very large.

The present invention proposes application to an illumination light device such as a light control device by utilizing this large magneto-optical effect. By the way, the fact that a magneto-optical effect occurs for a magnetic fluid means that magnetic fine particles form clusters,
In other words, it means that the magnetic particles are solidified, which is a phenomenon that magnetic fluids do not want to occur. It should be noted that the concept is changed and originality is devised in that it tries to take advantage of such a bad part as a characteristic of the magnetic fluid.

The magnetic fluid is not a single-phase liquid, but is a suspension in which ferromagnetic fine particles such as magnetite (magnetite) are dispersed in a liquid such as kerosene or water. The ferromagnetic fine particles play a role of magnetizing the liquid under the action of the magnetic field, and the liquid plays unique properties of the liquid such as free deformation and flow. Therefore, strictly speaking, a magnetic fluid is a mixture of solid and liquid, that is, a solid-liquid two-phase fluid, but since the dispersed ferromagnetic fine particles are too small, it is almost the same as an ordinary single-phase liquid. does not change. The size of the ferromagnetic particles is about 100Å on average.

When the size of the ferromagnetic fine particles becomes as small as about 100Å, each ferromagnetic fine particle has a so-called single magnetic domain (1 particle 1 magnetic domain) structure in which it is magnetized to saturation.
Therefore, even if the ferromagnetic particles are simply dissolved in the liquid,
The ferromagnetic fine particles are attracted to each other by a magnetic attractive force and coagulate and precipitate. Therefore, in order to prevent aggregation, it is necessary to prevent the ferromagnetic particles from contacting each other.

Therefore, the individual ferromagnetic fine particles are coated with a molecule of a surfactant so that the ferromagnetic fine particles cannot come closer than a certain distance. Since the size of the ferromagnetic fine particles is about 100 times the size of the solvent molecules, the random collision of the solvent molecules prevents the ferromagnetic fine particles that perform Brownian motion from precipitating. Thus, the magnetic fluid exists as a stable colloidal solution due to the action of the surfactant and the Brownian motion.

The magneto-optical effect generally means that when a magnetic field is applied to a magnetic material, the optical characteristics of the magnetic material change. There are several types of magneto-optical effects, and for example, when a magnetic fluid is put between two parallel glass plates with a narrow gap and a magnetic field is applied, a unique interface change is exhibited. Changing the way the magnetic field is applied produces different magneto-optical effects for linearly polarized incident light.

When the magnetic fluid put between the parallel glass plates is magnetized in the thickness direction and linearly polarized light is made incident in the thickness direction, the polarization plane after passing through the magnetic body has an angle proportional to the thickness. Rotate by θ. This phenomenon is called the Faraday effect. Next, when linearly modified light is incident on the magnetized magnetic material, the reflected light becomes elliptically polarized light. This phenomenon is called the Kerr effect.

As shown in FIG. 3, when the magnetization direction and the light traveling direction are orthogonal to each other, the refractive index of the magnetic substance is different in the direction perpendicular to the magnetic field and parallel to the linearly polarized light perpendicular to the magnetization. The light that has passed through the magnetic substance is no longer linearly polarized light. This phenomenon is called the Cotton-Mouton effect.

The present invention utilizes the Cotton-Mouton effect, in which the magnitude of the magnetic field is controlled by creating a magnetic field with the electromagnet and adjusting the current flowing through the electromagnet. The light emitted from the light source lamp and transmitted through the polarizing plate is transmitted through the magnetized magnetic substance, so that the light is biased. The deviation of this light increases in proportion to the magnitude of the magnetization, that is, the magnitude of the current flowing through the electromagnet.Furthermore, by detecting it with a polarizing plate, the incident linearly polarized light passes through the magnetic fluid due to the phase difference, It emerges as elliptically polarized light from the polarizing plate.

Thus, the technical idea of the present invention is that the amount of light passing through the pair of polarizing plates sandwiching the magnetic fluid film changes when the magnitude of the magnetic field applied to the magnetic fluid film changes. It tries to use the law of nature for dimming in the field of lighting technology.

[0017]

【Example】

<Structure> The magnetic fluid dimming device of the present invention has, as an element for generating the shutter function, the magnetic fluid film 1 and the polarization directions which are arranged on the front surface and the rear surface with the film surface of the magnetic fluid film interposed therebetween. A pair of polarizing plates 2a, 2b, and means 3a, 3b for applying a magnetic field parallel to the film surface of the magnetic fluid film,
And a means 7 for variably controlling the magnitude of the applied magnetic field.

The magnetic fluid film 1 used as an example is
A suspension of ferromagnetic particles dispersed in a liquid is enclosed between two translucent non-magnetic plates (eg, glass plates) that are arranged in parallel with each other (eg, at intervals of 12 μm). Configured. The thickness of the magnetic fluid film in this example is 12 μm
Will be said.

As an example of the suspension as the magnetic fluid, kerosene, water, etc. are used.
N-304MO manufactured by Sigma High Chemical Co., Ltd., isoparaffin base, saturation magnetization 272 gauss (at 15 K Oe), weight concentration 30.0%, volume concentration 6.34%, specific gravity 1.06, It has a viscosity of 6.14 cp (at 20 ° C.). An example of the ferromagnetic fine particles contained therein is magnetite (magnetite) having an average particle size of 100Å, but even if these particles are simply dissolved in a liquid, the ferromagnetic fine particles attract each other by a magnetic attractive force, Aggregate and settle. In order to prevent such aggregation, it is sufficient to prevent the mutual contact of the ferromagnetic fine particles. Therefore, the ferromagnetic fine particles to form the magnetic fluid film 1 are such that the individual surfaces of the ferromagnetic fine particles are coated with a molecule of a surfactant so that the ferromagnetic fine particles cannot come closer than a certain distance. By coating in this manner, the ferromagnetic fine particles having a size of about 100 times the size of the solvent molecules perform Brownian motion due to random collision of solvent molecules, so that the ferromagnetic fine particles do not precipitate. Acts as a stable colloidal solution.

The means for applying the magnetic field may be either a permanent magnet or an electromagnet. The control of the magnitude of the magnetic field can be performed by changing the mutual position of a pair of permanent magnets in the former case,
Alternatively, the latter case can be realized by rotating the mutual positional relationship of the magnets, and the latter case can be realized by changing the current intensity. Although a battery is used as an example of the power source, it goes without saying that a commercial AC power source can be used.

The light fixture with the dimmer is a light source lamp 4
(For example, a discharge lamp or a halogen bulb), a light reflection plate 5 arranged to cover at least the rear surface of the light axis of the light source lamp, and a condenser lens 6 arranged on the front surface of the light axis as necessary. A light source, and in front of the optical axis of the light source,
Light control including a magnetic fluid film 1 which is provided with magnetic field applying means 3a and 3b for applying a magnetic field parallel to the magnetic fluid film 1 sandwiched by a pair of polarizing plates having different polarization directions. It is configured by arranging the device.

<Operation> As shown in FIG. 1, when a magnetic field is applied in parallel to the film surface 1 of the magnetic fluid (that is, perpendicular to the thickness direction of the film), the transmittance by the magnetic fluid is reduced as shown in FIG. The transmittance is indicated by the one-dot chain line shown in FIG. Therefore, the transmittance of the wavelength characteristic of the optical energy as shown by the broken line changes to the transmittance as shown by the solid line. Therefore, visible light with a short wavelength can be controlled almost.

FIG. 4 shows the change characteristic of the amount of transmitted light of the magnetic fluid caused by the change of the magnetic field. The maximum transmitted light flux is 4 μm thick, but the rate of change from the initial transmitted light flux is 1
It can be seen that the 2 μm thin film is the largest. This relationship is
As a result of simulating the amount of change from the initial value (electric field 0),

[0024]

[Equation 1]

However, n ∥ represents the refractive index in the direction parallel to the magnetic field (refractive index for extraordinary light), and n ⊥ represents the refractive index in the direction perpendicular to the magnetic field (refractive index for normal light). It turned out that it is shown by.

FIG. 5 shows the relationship between the transmittance of magnetic fluid and the magnetic field characteristics when a fluorescent lamp [FLR40S.D / M manufactured by Toshiba Lighting & Technology Corporation] is used as a light source lamp and a halogen lamp [Iwasaki Electric Co., Ltd.]. 3000K / E1 manufactured by Co., Ltd.
7] is used to show the illuminance ratio-magnetic flux density characteristics. When a fluorescent lamp is used, the initial illuminance (illuminance when no magnetic field is applied) is 100 due to the change in magnetic field due to the magnetic fluid thin film.
The illuminance change ratio when converted to is the magnetic flux density of 0.15
[T] is four times larger. It is shown that the transmittance is improved by the magneto-optical effect by applying the magnetic field.

By using a non-mechanical (electrical) control system as in the present invention, remote operation or electrical automatic control using a computer or the like becomes possible, and it is possible to incorporate it into a series of limiting systems. Become. Therefore, the present invention is a very effective and new method for incorporating into a new dimming control system such as a stage or a television studio, which continues to be dizzyingly high-performance, multifunctional, and computerized at present.

When the dimmer is incorporated in the lighting equipment,
As shown in FIG. 6, a fixture having a long illumination tube (for example, follow spotlight MH6-2 manufactured by Art Dees Co., Ltd.)
M, a light source HM1-575W) may be incorporated in the front part to house an electromagnet having a power source for variably controlling the magnetic field.
Further, a control system device for adjusting a magnetic field of a remote control system can be added to the power source. The dimming control requires analog variable, but basically, the scale of the illuminance ratio of about 100 steps is set.

[0029]

According to the electronic circuit type dimmer using the transistor in the conventional lighting equipment, the electromagnetic wave generated due to the intermittent operation of the current infiltrates into the electronic circuit of the audio / video equipment to cause noise. Since there is a problem of occurrence of noise or disturbance of waveform, it is often done by a mechanical shutter type dimmer. However, the present invention solves such a problem, and the dimming of a discharge lamp can be performed in a multi-step analog manner and with a small dimming sound, a high dimming speed, and miniaturization. Made possible The following table shows the special effects of the present invention by comparing the specifications of the magnetic fluid dimming device of the present invention and the conventional mechanical shutter.

[0030]

[Table 1]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a lighting fixture including a magnetic fluid dimming device of the present invention.

FIG. 2 is a diagram showing a relationship between a transmittance of a magnetic fluid film and a wavelength.

FIG. 3 is a schematic diagram of the Cotton-Mouton effect.

FIG. 4 is a diagram showing the relationship between the permeability of magnetic fluid and magnetic properties.

FIG. 5 is a diagram showing a relationship between an illuminance ratio and a magnetic flux density.

6A and 6B are views showing a light control section of the lighting fixture, wherein FIG. 6A is a vertical cross-sectional view, and FIG. 6B is a cross-sectional view cut along the line AA shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic fluid film 2a, 2b 1st polarizing plate, 2nd polarizing plate 3a, 3b Electromagnet 4 Light source lamp 5 Reflector 6 Lens 7 Control means 8 Lens 9 Outer box

Claims (4)

[Claims] 1. A magnetic fluid shutter comprising: a magnetic fluid film sandwiched between a pair of polarizing plates having different polarization directions; and a means for variably applying a magnetic field parallel to the film surface. A magnetic fluid dimming device arranged in front of the optical axis. 2. A magnetic fluid film, a pair of polarizing plates arranged on the front surface and the rear surface of the magnetic fluid film sandwiching the film surface and having different polarization directions, and parallel to the film surface of the magnetic fluid film. A means for applying a magnetic field and a means for controlling the magnitude of the magnetic field are provided, and by controlling the magnitude of the magnetic field, the amount of light vertically passing through the surface of the magnetic fluid film is variably adjusted. Magnetic fluid dimmer. 3. The magnetic fluid film is formed by enclosing a suspension obtained by dispersing ferromagnetic fine particles in a liquid between a pair of translucent non-magnetic plates arranged in parallel in close proximity to each other. And that each surface of the ferromagnetic fine particles is coated with a molecule of a surfactant so that the ferromagnetic fine particles cannot come closer than a certain distance. Item 1. The magnetic fluid dimming device according to Item 1 or 2. 4. A light source, the magnetic fluid dimming device according to claim 1, 2 or 3 arranged in front of the optical axis of the light source, and light reflection arranged so as to cover at least the rear surface of the optical axis of the light source. And a magnetic field applying means for applying a magnetic field parallel to the film surface of the magnetic fluid film sandwiched by a pair of polarizing plates having different polarization directions. And an amount of light passing through the magnetic fluid dimming device can be changed by variably controlling the magnitude of the magnetic field applied by the magnetic field applying means. apparatus.