WO2003052476A1

WO2003052476A1 - Optical device comprising a liquid optical agent

Info

Publication number: WO2003052476A1
Application number: PCT/EP2002/014382
Authority: WO
Inventors: Karsten Reihs
Original assignee: Sunyx Surface Nanotechnologies Gmbh
Priority date: 2001-12-19
Filing date: 2002-12-17
Publication date: 2003-06-26
Also published as: DE10162816A1; AU2002360994A1

Abstract

The invention relates to an optical device comprising at least one optical agent, which consists of a liquid, and has at least one ultraphobic surface on which the optical agent can be displaced. The device is preferably an optical switch.

Description

OPTICAL DEVICE WITH LIQUID OPTICAL AGENT

The present invention relates to an optical device with at least one optical means, which consists of a liquid and which has at least one ultraphobic surface on which the optical means is displaceable.

The increasing use of glass fibers in the field of telecommunications also increases the interest in purely optical multiple switches, which can be used both in switching centers and for the production of easily changeable circuits. Monomode technology in particular is a challenge for such switching tasks.

N x M switching matrices, which enable the connection of N-optical input channels to M-output channels (N, M> 2), are suitable for such tasks. The matrix-like arrangement of the switching elements enables the number of input and output channels to be expanded using the same concept.

In this case, light beams of the inputs that are supplied by means of glass fibers are deflected onto the outputs by movable optical elements, such as, for example, lenses or mirrors. So far, the optical means were moved with servomotors. However, this concept has turned out to be comparatively expensive, slow and maintenance-intensive.

The object of the present invention was therefore to provide an optical device which does not have the disadvantages of the prior art.

This object is achieved by an optical device with at least one optical means which consists of a liquid and which has at least one ultraphobic surface on which the optical means can be displaced.

It was extremely surprising to the person skilled in the art and it was not to be expected that it would be possible with this device to implement an optical switch in which the optical means can be moved with almost no loss of friction and fluid and wear. With the optical device, the optical means can be moved very quickly and precisely. The optical device is simple and inexpensive to manufacture.

Any liquid known to a person skilled in the art can be used as the liquid optical medium. However, the means are preferably optical lenses or mirrors. In the case of lenses, the liquid is preferably water. Likewise, liquids can preferably be used which are optically transparent at the wavelength of the light with which the optical switch is operated and preferably have a high surface tension.

In the case of a mirror, the liquid is preferably a liquid which strongly wets out on an ultraphobic surface, a thin air film being formed between the liquid and the surface, on which an optical total reflection occurs, which can be used as a mirror. For this purpose, water or oils on transparent ultraphobic surfaces are suitable, where the respective drop of liquid has a contact angle> 150 °.

The liquid, optical means are preferably shifted by electrical fields, which can preferably be generated by a grid of essentially uniformly distributed electrodes that can be controlled individually.

The grid preferably has at least 5x5 = 25, particularly preferably at least 16x16 = 256 and very particularly preferably at least 20x20 = 400 electrodes. The electrodes can each be connected individually to an electrical voltage source with preferably 10 to 1000 V, particularly preferably 100 to 300 V, so that an electrical field can be generated with each electrode independently of the other electrodes. The electrodes are preferably arranged at a distance of <100 μm, particularly preferably <50 μm and very preferably <10 μm, and preferably have a dimension of 150 μm, particularly preferably <70 μm and very particularly preferably <20 μm.

The voltage source is preferably controlled by an automated control unit, for example a computer, and the individual electrodes are thus individually supplied with electrical voltage. With the The computer determines which electrode is to be connected to an electrical voltage at what time and for how long. In this way it can be determined which path on the hydrophobic surface a liquid drop travels at which speed. The control of the electrodes by the automated control unit can be changed at any time.

In a preferred embodiment of the present invention, not only one but a plurality of electrodes, preferably at least two, particularly preferably at least four electrodes, are controlled simultaneously. When two electrodes are actuated, these are preferably adjacent to one another and when four electrodes are actuated, they are preferably arranged in a carriage.

The electrodes are preferably arranged in the vicinity of the surface of a carrier. This carrier is preferably covered with a film with an ultraphobic surface.

An ultraphobic surface in the sense of the invention is characterized in that the contact angle of a drop of water lying on the surface is more than 150 ° and the roll angle does not exceed 10 °. The roll angle is understood to be the angle of inclination of a basically planar but structured surface against the horizontal, at which a standing water drop with a volume of 10 μl is moved due to the force of gravity when the surface is inclined. Such ultraphobic surfaces are described, for example, in WO 98/23549, WO 96/04123, WO 96/21523, WO 00/39369, WO 00/39368, WO00 / 39239, WO 00/39051, WO 00/38845 and WO 96 / 34697, which are hereby introduced as a reference and are therefore considered part of the disclosure.

In a preferred embodiment, the ultraphobic surface has a surface topography in which the spatial frequency of the individual Fourier components and their amplitude a (f) are expressed by the integral S (log (f)) = a (f). f calculates between the integration limits log (fi / μm ^"1 ) = -3 and log (fi / μm ^{" 1} ) = 3 is at least 0.3 and which is made of a hydrophobic or, in particular, oleophobic material or of a durable, hydrophobic or, in particular, durable oliophobic Material exists. Such an ultraphobic Surface is described in international patent application WO 00/39240, which is hereby introduced as a reference and is therefore considered part of the disclosure.

The optical device can be any optical instrument known to those skilled in the art. However, the optical device is preferably an optical switch in which one or more optical input channels are each switched to one of a plurality of optical output channels. In this application, the optical means is preferably a spherical lens or a mirror.

By moving at least one optical means on the ultraphobic surface, a light beam is deflected from an input channel to one of a plurality of output channels.

In a further preferred embodiment of the present invention, the optical properties of the optical means are changed by electrical fields. Optical properties in the sense of the invention are preferably the refractive index and the curvature of lenses, preferably spherical lenses, or the curvature of mirrors. In this preferred embodiment of the present invention, the optical means is not only shifted, but its overall optical properties are changed, so that additional parameters for the design of optical devices are available to the person skilled in the art. The person skilled in the art understands that the shifting of the optical means and the change in their optical properties can, but does not have to, take place independently of one another.

Another object of the present invention is an optical device with a liquid optical means, characterized in that at least one optical property of the means is reversibly changeable by an electric field.

Optical properties in the sense of the invention are preferably the refractive index and the curvature of lenses, preferably spherical lenses, or the curvature of mirrors. It was extremely surprising for the person skilled in the art that with liquid optical means it is possible to achieve different optical properties reversibly and very quickly by applying an electrical field. The device is simple and inexpensive to manufacture.

The means is preferably a spherical lens, which consists of a spherical drop of liquid, the curvature of which can be reversibly changed.

The agent is preferably stored on an ultraphobic surface, as has already been described above. This embodiment has the advantage that a drop on the ^' ultraphobic surface takes at least approximately the shape of a sphere and can be moved on the ultraphobic surface without loss.

In a preferred embodiment of the present invention, the optical device is an optical switch. By changing the optical properties, it is possible to switch light from one input channel to one of several output channels without having to move the optical means.

The invention is explained below with reference to FIGS. 1, 2, 2a-2c. These explanations are only examples and do not limit the general idea of the invention.

Figure 1 shows an embodiment of the optical switch according to the invention.

Figure 2 shows a further embodiment of the optical switch according to the invention.

Figures 2a 2b show two states of a switchable mirror

Figure 2c shows the principle of a mirror based on an ultraphobic surface. FIG. 1 shows an embodiment of the optical switch according to the invention, which has three input channels E1-E3 and three output channels A1-A3. Light signals are passed through the input channels E1-E3 into the optical switch and there redirected to one of the output channels A1-A3. This is illustrated by way of example in FIG. 1 on the input channel E2 and on the output channel A1. A light signal is passed via the light guide E2 into the optical switch and bundled there by the water drop 1, which represents an optical lens, and is reflected by the optical structure, which consists of nine partially reflecting mirrors 5, onto the output channel A1. Before the light signal leaves the optical switch through the output channel A1, it is expanded again by the water drop 3, which is also an optical lens. The optical switch also has an ultraphobic surface 4, on which the water plugs have a contact angle of 174 °. Immediately below the ultraphobic surface are two grids with electrodes, each of which can be controlled with an electrical voltage in any order and for any duration, as a result of which a drop of water can be positioned very precisely and very quickly on or between the respective electrodes of the grid. Those skilled in the art recognize that the grid does not have to be a 3 x 3 matrix, but can be much finer or coarser. By changing the position of the two water drops, the light signals of the input channels E1-E3 are focused on different partially reflecting mirrors 5 and accordingly diverted to different output channels A1-A3. The possible switching states and the associated positions of the water drops 1, 3 are summarized in Table 1. An input signal can be redirected to different output channels very quickly and without any mechanical parts in the form of moving solid bodies.

FIG. 2 shows a further embodiment of the optical switch according to the invention, which has three input channels E1-E3 and three output channels A1-A3. Light signals are passed through the input channels E1-E3 into the optical switch and there redirected to one of the output channels A1-A3. This is illustrated by way of example in FIG. 1 on the input channel E2 and on the output channel A1. A light signal is passed via the light guide E2 into the optical switch and deflected by the switchable mirror 7 onto the output channel A1. The mode of operation of the switchable mirror is further illustrated in FIGS. 2a-2c explained below. The optical switch also has an ultraphobic surface 6 on which the water plugs have a contact angle of 174 °. Through the respective switching of the switchable mirrors, the light signals of the input channels E1 - E3 are redirected to different output channels A1 - A3.

The function of the switchable mirror can be seen from FIGS. 2a-2c. As shown in FIG. 2c, the switchable mirror is based on a transparent, ultraphobic surface 12, an air film 11 and a liquid 10, which in the present case is water. Due to the ultraphobicity of the surface 12, an air film 11 is formed between it and the liquid 10, which is totally reflective, i.e. acts like a mirror. This relationship is shown using the light beam 9.

The further function of the switchable mirror is explained with reference to FIGS. 2a and 2b. A drop of liquid 8, in the present case water, is moved with an electric field along an ultraphobic surface. Due to the ultraphobicity of the surface 12, an air film is formed at the points at which the liquid drop 8 covers the surface 12, which film has a total reflection. At the points on the surface 12 where the liquid drop 8 is not located, the surface 12 is transparent to the respective light. FIG. 2a shows the state in which the switchable mirror has a reflective effect because the liquid drop 8 is in the path of the light beam 9. Figure 2b shows the state in which the liquid drop 8 has been moved to the left with an electric field. With this setting of the switchable mirror, the light beam is only refracted but not reflected on the transparent, ultraphobic surfaces. The switchable mirror can therefore be switched between the mirroring or translucent states as desired. In Figure 2, the switchable mirror in column 1, row 2 is totally reflective and the switchable mirror in column 1, row 3 is transparent. .

Table 1

Claims

claims:

1. Optical device with at least one optical means (1, 3, 8, 10) consisting of a liquid, characterized in that it has at least one ultraphobic surface (4, 6, 12) on which the optical means is displaceable ,

2. Optical device according to claim 1, characterized in that ^ the means (1, 3, 8, 10) is an optical lens or a mirror.

3. Optical device according to one of the preceding claims, characterized in that the optical means is displaceable with an electrical field.

4. Optical device according to one of the preceding claims, characterized in that it is an optical switch.

5. Optical device according to claim 4, characterized in that the means (1, 3, 8, 10) is a spherical lens.

6. Optical device according to claim 4 or 5, characterized in that by moving at least one means (1, 3, 8, 10) on the ultraphobic surface (4, 6, 12) a light beam from an input channel to one of several output channels can be deflected is.

7. Optical device according to one of the preceding claims, characterized in that at least one optical property of the optical means, preferably its refractive index and / or its curvature, can be changed by an electric field.

8. Optical device with at least one liquid optical means, characterized in that at least one optical property of the means, preferably its refractive index and / or its curvature, is reversibly changeable by an electric field.

9. Optical device according to claim 8, characterized in that the means is a spherical lens, the curvature of which is reversibly changeable.

10. Optical device according to claim 8 or 9, characterized in that the agent is mounted on an ultraphobic surface.

11. Optical device according to one of claims 8 - 10, characterized in that it is an optical switch.

12. Optical device according to claim 11, characterized in that a supplied light beam can be deflected from an input channel to one of several output channels by changing the optical properties of the agent.