RU2616437C1 - Optical sensory fabric structure - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: optical sensory fabric consists of two layers formed by side-firing light guides perpendicular to each other, with polarization coating applied to their lateral surface, which internal structure is symmetrical about the axial line of the light guide. Light guide cores of one of the layers are optically interfaced with corresponding emitters, connected to the computing machine outputs, while light guide cores of the second layer are optically interfaced with corresponding photoelectric detectors, connected to the computing machine inputs.

EFFECT: increased functionality, improved reliability.

18 cl, 25 dwg

Description

The proposed optical sensory fabric relates to techniques for constructing user interfaces that are embedded in clothing, shoes and military uniforms, as well as in other objects of a specific shape. In robotics, this solution will allow you to "feel" the manipulators and various structural surfaces.

According to the principle of functioning, the device of sensory tissue can be assigned to systems of active optical location.

A number of devices for this purpose are known. So the company STMicroelectronics (IT) patented a capacitive woven sensor that responds to the pressure exerted by the user on its surface [1].

Heimbach GmbH & Co (DE) has patented a textile product with an integrated piezoelectric sensor that measures pressure and temperature [2].

A patent is known for a textile structure with an integrated optical interface by Electronics and Telecommunications Research Institute (KR) [3]. In this device, fiber-optic threads mounted in a fabric serve to organize communication between mobile devices.

In the patent, owned by Milliken & Company (US), a structure is proposed consisting of an optical fiber passing through the main set of filaments, at the edges of which a light source and a detector are placed [4]. This device allows you to determine the point of user exposure to this structure by measuring the light leakage that occurs when the fiber bend changes at the point of contact. The disadvantage of this device is obvious - low sensitivity, requiring large bends of the optical fiber, and the consequence of this is the error caused by its wear.

There are a large number of patents based on fiber optic technology, but which, nevertheless, do not allow to obtain a flexible touch surface. Examples are the patent of Nitta Corporation (JP), which records the contact of input apertures of optical fibers [5], and the patent of Nitto Denko Corporation (JP), built on the basis of optical channels integrated into the polymer base [6]. A similar principle is presented in US patents [7], [8], [9], [10], [11] and [12]. All of them contain one set of receiving and transmitting optical fibers, and the output ends of the transmitting optical fibers are optically coupled to the input ends of the receiving optical fibers, to which the infrared radiation of the laser or LED is supplied. The output ends of the receiving optical fibers are optically coupled to photodetectors, or, as suggested in [13], to a photodiode array.

The devices proposed in patents [14] and [15] incorporate flexible films on which current-carrying electrodes are formed, but they cannot be considered fully “flexible”, because it is impossible to give their surface an arbitrary shape.

A large class of devices called “tactile sensors” is represented by the patents listed below.

So firms Seiko Epson Corporation (JP) proposed an ultrasonic tactile sensor [16], SynTouch (US) - a spongy material coated with leather, combined with a pressure sensor [17]. Samsung Electronics Co., Ltd. (KR), a flexible tactile sensor based on nanoconductors located on the upper and lower plates is patented, and by measuring the resistance between the upper array of conductors and the lower one, the distance between them can be determined and, as a result, the applied force and its position [18].

Massachusetts Institute of Technology (US) proposed a device consisting of an elastomer illuminated by an external radiation source [19, 20, 21]. In this case, a change in the geometry of the elastomer in response to an external effect causes a change in the reflection of the light flux from the elastomer towards the photodetector. The presence of opaque finely dispersed structures in the elastomer allows the position of the force acting on the elastomer and the degree of its deformation to be determined during the processing of the photodetector signal.

The article [22] considered the construction of fiber optic sensors and sensors based on changes in optical loss and wavelength of radiation passing through them under deformations and temperature.

In [23], the construction of a tactile sensor based on measuring the losses in a fiber arising from its mechanical deformation was considered.

In [24], a tactile sensor made in the form of a four-layer structure is described. The upper and lower layers do not have optical properties and can be made of thin wire. The second and third layers are optical fibers (optical fibers) of a standard communication cable with an external diameter of 125 μm and a core with a diameter of 52 μm and form a square grid with cells from 2 × 2 to 6 × 6 mm. The input ends of the optical fibers are illuminated by infrared diodes, and the output optically coupled to photodetectors connected to a computing device. A change in optical attenuation in optical fibers caused by their deformation when exposed to an external force is recorded by a computing device. Thus, the coordinate of applying an external force to the surface of the tactile sensor can be determined. The disadvantage of this device is the need for direct application of external force to the optical fibers, to ensure their deformation. This device is closest in its functioning to the proposed one and is its prototype.

The aim of the invention is to increase the functionality, which consists in the fact that it allows you to determine the coordinate of the object, until they touch the sensory tissue. Thus, no external force is needed to determine the coordinate. This in turn increases reliability by eliminating the possibility of microcracks in the fiber. In contrast to the prototype, another functional feature of the proposed technical solution is the ability to simultaneously measure the coordinates of several objects that are within the optical connection with sensory tissue, as well as the overall characteristics of the object.

A device [24] is known that contains two layers perpendicular to optical fibers, in which the fibers of the first layer are optically coupled to the emitters and the fibers of the second layer are optically coupled to the photodetectors. In addition, the composition of this device includes a computer, the outputs of which are connected to the emitters, and the inputs to the outputs of the photodetectors.

The difference between the proposed technical solution and the prototype is that the optical fibers belong to the class of “lateral glow” optical fibers or to fluorescent ones, in addition, a polarizing coating is applied to their surface in the form of a regular structure consisting of metallized strips or wires separated by a spatial gap. The plane of polarization of this structure should be selected along or across the central axis of the optical fiber. Instead of metallized strips or wire, triangular cuts can be made on the surface of the optical fibers, one of the faces of which is coated with a metallized coating.

Thus, unpolarized radiation entering the input end of the fiber of the first layer using the corresponding emitter is reradiated by its lateral surface already in a polarized state.

Based on the principle of reversibility of light rays, a fiber with the property of luminosity on the outer surface concentrates the radiation incident on it in the core, and then moves it to its ends. In addition, the presence of a polarization structure on the surface of the optical fiber damps the radiation directly incident on this surface from the optical fibers of the first layer, because The polarization directions of these layers are mutually perpendicular.

The appearance on the path of the radiation generated by the optical fibers of the first layer, the object of control, causes the reflection of the radiation incident on it, including partially in the direction of the optical fibers of the second layer. Propagating through the core, part of this radiation reaches the end and enters the surface of the corresponding photodetector.

The computer generates at its outputs signals of successive switching on of emitters, while the streams of polarized radiation created by this scan the space above the sensor tissue. By simultaneously synchronizing with each switching on of the emitter, the input of photodetector signals optically coupled to the fibers of the second layer (all photodetectors for each switched-on emitter) and subsequent processing of these signals, it is possible to determine the position of one or more monitored objects, or an object of complex topology, reflecting radiation towards the optical fibers second layer.

In other words, the position of the control object located in the optical location zone of the proposed sensor tissue can be uniquely localized.

The functioning and device of the proposed optical sensory tissue is illustrated by the following figures:

FIG. 1 is a functional diagram of an optical sensory tissue, where:

1 - optical fibers of the first layer;

2 - fibers of the second layer;

3 - optical emitters;

4 - photodetectors;

5 - calculator;

6 - control object;

μ - optical connection of the control object 6 with the optical fiber 1;

ν - optical connection of the control object 6 with the optical fiber 2.

FIG. 2 - the first embodiment of the optical fibers, where:

7 - the core of the fiber;

8 - scattering layer;

9 - a protective shell;

10 - polarization layer;

11 - metallized strip;

M is an enlarged image of a fragment of the polarization layer;

ξ is the step of placing metallized strips;

C is the optical axis (center line) of the fiber;

D is a circle centered on C and perpendicular to it;

Ψ _T is the direction of the input or output optical streams;

,

,

,

- направления поляризации выходного или входного оптического потока.

,

,

,

- polarization directions of the output or input optical stream.

FIG. 3 - the second embodiment of the fiber, where:

,

,

,

- направления поляризации выходного или входного оптического потока,

,

,

,

- polarization directions of the output or input optical stream,

e is the surface of the cylinder described around axis C.

FIG. 4 - the third embodiment of the fiber, where:

12 - grooves of a triangular profile.

FIG. 5 - the fourth embodiment of the fiber.

FIG. 6 - the fifth embodiment of the fiber, where:

13 - the outer shell.

FIG. 7 - the sixth embodiment of the fiber.

FIG. 8 is a geometric diagram of the active location of the object 6, where:

1 _a - a-th fiber of the first layer;

2 _b - b-th fiber of the second layer;

F _a - optical flux emitted by the a-m optical fiber of the first layer;

ϕ _a is the optical flux reflected by the control object 6;

ϕ _b is the optical flux incident on the surface of the b-th fiber of the second layer.

FIG. 9 is a timing diagram of the signals of the calculator 5, where:

T _a-1 , T _a , T _{a + 1} , ... T _ω - turn-on signals u-1, u, u + 1, ... ω emitters;

P (s, a-1), P (s, a), P (s, a + 1), P (s, ω) are the photodetector signals s = 1 ... p, with a-1, a, a + turned on 1, ... ω emitters, respectively.

FIG. 10 is a 3D image of the function P (s, u).

FIG. 11 is a geometric diagram of the active location of the control object of complex topology, where:

6 ₁ , 6 ₂ , 6 ₃ , 6 ₄ , 6 ₅ - 1 ... 5th fragments of the control object 6;

14 - optical sensory tissue.

FIG. 12 is a 3D image of the function P (s, u) for an object of control of complex topology, where:

P ¹ (s, u), P ² (s, u), P ³ (s, u), P ⁴ (s, u), P ⁵ (s, u) - 1 ... 5th domain of the function P (s , u) corresponding to fragments of object 6.

FIG. 13 is a variant of the geometric arrangement of the first and second layers of optical fibers above the radiation absorbing material, where:

15 - absorbent woven pad;

16 - fastening fiber;

17 - base.

FIG. 14 is an illustration of the location of the first and second layers of optical fibers between the woven strip, where:

18 - opaque woven pad.

FIG. 15 is an illustration of the interweaving of the optical fibers of the first and second layers.

FIG. 16 is an illustration of the adhesive fastening of the optical fibers of the first and second layers, where:

19 - adhesive bonding.

FIG. 17 is an illustration of the shielding of adjacent fibers using an additional fiber, where:

20 - shielding fiber;

P _{a, a + 1} - spurious radiation;

S _{a, a + 1} - shadow segment.

FIG. 18 is a fragment of an optical sensory tissue supplemented with shielding fibers.

FIG. 19 - the use of an opaque braid on free sections of optical fibers, where:

20 - free section of the fiber,

21 - the outer braid of the fiber,

22 - printed circuit board.

FIG. 20 - the use of fiber optic with end glow in free sections of the optical fibers, where:

23 - optical fiber with end glow,

24 - welded or adhesive bonding of fibers.

FIG. 21 is an example of increasing the radiation flux of the optical fibers of the first layer, where:

25 - a group of parallel placed optical fibers of the first layer.

FIG. 22 is an example of increasing the sensitivity of the second layer of optical fibers, where:

26 - a group of parallel placed optical fibers of the second layer.

FIG. 23 - optical fibers placed in groups in the first and second layers.

FIG. 24 is a fragment of a multi-lens coating, where:

27 - lens (condenser);

28 - supporting coating;

O is the optical center of the lens 27;

ƒ is the focal length of the lens 27;

D _C is the diameter of the lens 27;

D _B - the diameter of the fiber 1;

σ is a fragment of the emitted surface;

σ _Λ - image of σ;

χ - image of σ _Λ .

FIG. 25 is an example of an optical sensory tissue using a “lens array”.

The arrangement and functioning of the optical sensory tissue is illustrated in FIG. one.

Two layers of optical fibers 1 and 2 are placed perpendicular to each other, one layer above the other. We will further consider layer 1 as the upper layer and layer 2 as the lower layer, with the upper layer located on the side where the control object 6 is located, and layer 2 is facing the object on which this fabric is placed. The ends of the optical fibers of the upper layer 1 are optically coupled to the emitters 3, and the ends of the optical fibers of the lower layer 2 are optically coupled to the photodetectors 4.

The optical fibers used in the proposed sensor tissue have, among other things, the well-known property of the luminosity of the side surface.

This type of fiber emits light from the outside of the fiber, when the light stream is directed to its central part. Known fibers with this property are the so-called "luminescent optical fibers" [25]. The material of these fibers during the production process is doped with the corresponding active material. Radiation entering transversely into the fiber interacts with additives in the core. The resulting optical radiation, which in principle is isotropic, is generated if the wavelength of the exciting radiation corresponds to the absorption characteristics of the impurity.

The lateral emission fibers made on the basis of polymeric materials, the so-called POFs, are widely used [26].

This type of optical fiber consists of a core through which the radiation introduced into the optical fiber propagates, a scattering layer containing dispersion material, scattering radiation, partially penetrating into this layer from the core, and a protective sheath.

However, the known optical fibers do not have the property of polarizing the radiation emitted by the side surface or incident on it.

To impart this property, the following is proposed. A polarizing layer is applied to the surface of the optical fibers in the form of a regular structure consisting of metallized strips or wires separated by a spatial gap - the so-called “Metal mesh based components” [27, 28, 29, 30]. In FIG. 2 shows a fragment of optical fibers 1 and 2, with a polarizing layer deposited on them.

An example of the implementation of this type of polarizer deposited on a flat surface is described in [27, p. 89-90].

The unpolarized luminous flux of the emitter 3 enters the end of the fiber 1 and propagates along its core 7. Then, partially dispersed by the layer 8, entering and propagating in the protective sheath 9, it passes through the polarization layer 10 deposited on the outer surface of the protective sheath 9, acquiring the polarized property.

показывает направление поляризации излучаемого световодом 1 оптического потока.An enlarged image of the polarization layer 10 is depicted as a leader M. It consists of metallized strips 11 deposited on a protective sheath and parallel to the optical axis C, the pitch between which ξ is less than the working wavelength λ (included in the polarizer from emitter 4).

shows the direction of polarization of the optical stream emitted by the optical fiber 1.

Thus, taking into account the symmetrical arrangement of the metallized strips 11 relative to the optical axis C of the fiber, a light flux is emitted from the surface of the fiber 1, the polarization direction of which is also symmetrical to the optical axis C.

.In FIG. 3 shows a fragment of fiber 1 with a polarizer of this type deposited on it, the difference of which from that shown in FIG. 2 consists in the direction of the metallized strips 11, perpendicular to the direction of the optical axis C, and, accordingly, in the direction of the polarization vector

.

It is also true for him that, given the symmetrical arrangement of the metallized strips 11 relative to the optical axis C of the fiber, a light flux is emitted from the surface of the fiber 1 whose polarization directions are symmetrical to the optical axis C and lie on the surface of the cylinder e, the side surface of which is parallel to the optical axis C.

To form an optical polarizer, a structure similar to that described in [30] and depicted in FIG. 4. This type of polarization layer is formed by applying onto the protective layer 9 grooves of a triangular profile 12, on one of the faces of which a metallized coating 11 is applied.

.In FIG. 5 shows a structure almost similar to that shown in FIG. 4, with a different direction of grooving of the triangular profile 12 and, accordingly, the direction of the polarization vector

.

In FIG. 6 shows a light guide in which a polarizing layer 10 is deposited directly on the scattering layer 8, and a protective layer 9 on top of the polarizing layer. This increases the reliability of the polarization layer during mechanical stresses on the fiber. The appearance of an additional refracting gap - the thickness of the protective layer 9, can slightly rotate the direction of polarization of the refracted rays passing through it. However, for the rays incident from the optical fibers of the first layer onto the optical fibers of the second layer having a similar refracting gap, the polarization angle returns to the original angle determined by the direction of the metallized strips 11.

In FIG. 7 shows a variant different from that shown in FIG. 6 by the direction of the polarization strips 11.

For the manufacture of a polarizer deposited on the side surface of a fiber, a manufacturing technology owned by the US Navy [31] based on the holographic formation of images of parallel elements on the surface of a material treated with photoresist can be applied.

Thus, unpolarized radiation entering the input end of the fiber of the first layer is reradiated by its lateral surface already in a polarized state. It can be noted that in the case of using polarized radiation entering the input end of the fiber of the first layer, it is depolarized during repeated reflection in the core 7, which in any case requires the presence of a polarization layer 10 on the fiber.

As mentioned above, optical fibers 1 and 2 are similar to each other, i.e. have the same polarization layer 10. In this case, the fiber having the property of luminosity of the outer layer, according to the law of the reversibility of light rays, described for example in [32, p. 255], will concentrate the radiation incident on its surface into the core, through which the radiation propagates to its end . The use of this property is considered in [25 p. 210, 213]. Ibid. On fig. 8.6 presents a device for determining the size of an object whose shadow falls on an optical attenuator based on a fluorescent optical fiber, i.e. fundamentally fiber side glow.

и

определяют оси, в направлении которых поглощение излучения практически отсутствует, т.е. так называемые «оси свободного пропускания» [33, стр. 362].Polarization directions

and

determine the axes in the direction of which radiation absorption is practically absent, i.e. the so-called "axis of free transmission" [33, p. 362].

,

,

, образуют касательные к окружности D, выходящей за пределы боковой поверхности световода, причем центр D расположен на оптической оси С.For the polarization coating 10 shown in Figures 2, 4 or 6, the free transmission axes will be perpendicular to the central optical axis C, the optical fibers 1 or 2, forming tangent to the surface of the polarizing coating 10. Or, as shown in FIG. 2, these axes, for example

,

,

form tangents to a circle D extending beyond the lateral surface of the fiber, and the center D is located on the optical axis C.

,

,

, как было отмечено выше, лежат на поверхности цилиндра е, боковая поверхность которого параллельна оптической оси С.For the polarization coating 10 depicted in figures 3, 5 or 7, the free transmission axes will be parallel to the central optical axis C, the optical fibers 1 or 2. In FIG. 3 these axes, for example

,

,

as noted above, lie on the surface of the cylinder e, the side surface of which is parallel to the optical axis C.

The polarization coating 10 of the optical fibers of the first layer absorbs the electrical component E _{X of the} optical radiation emanating from the core 7 of the optical fiber 1 parallel to the metallized strips 11 forming the polarizing coating 10. As a result, the optical flux emanating from the surface of the optical fiber 1 acquires a polarization perpendicular to the direction of the metallized strips 11 .

или

взаимно перпендикулярны, что определено перпендикулярным расположением световодов 1 и 2 в оптической сенсорной ткани. Таким образом, отсекается паразитное, не несущее полезной информации излучение. В данном контексте «полезную информацию» несет излучение, отраженное от объекта контроля.The polarization coating 10 of the optical fibers of the second layer absorbs polarized radiation directly incident on it from the optical fibers of the first layer, because polarization directions of these layers -

or

mutually perpendicular, which is determined by the perpendicular arrangement of the optical fibers 1 and 2 in the optical sensory tissue. Thus, spurious radiation that does not carry useful information is cut off. In this context, “useful information” is the radiation reflected from the control object.

If the surface of the control object 6 does not possess the anisotropy and mirror properties, the radiation reflected from it loses the property of completely polarized [32, chapter XXIII]. As a result, the radiation, with the electric component E _Y perpendicular to the directions of the metallized strips 11 of the polarizing surface 10, and with the corresponding magnetic component, reaches the core 7 of the optical fiber 2. Further, propagating along it and depolarizing (as a result of multiple internal reflections), optical radiation reaches the end of the fiber and falls on the surface of the optically coupled photodetector 4.

In FIG. 8 illustrates the process of active optical location of the object 6 by the proposed device, and the energy center of the radiation incident on the control object 6 is located above the intersection of the optical fibers 1 _a and 2 _b . In this case, the radiation F _a formed by the a-m optical fiber of the first layer 1 _a is polarized in the direction indicated by E ₁ . Further, the part F _a is reflected from the control object 6 in the form of a depolarized radiation with directions E ₆ ϕ _a directed towards the bth fiber 2 _b . The optical flux ϕ _b , which is part of the optical flux ϕ _a , and has reached the surface of the optical fiber 2 _b , passes through the polarizing surface 10, reaches the core 7 of the optical fiber 2 _b , and propagates to its end, further reaching the photodetector 4 _b .

In FIG. 9 is a timing diagram illustrating the operation of the proposed device comprising ω optical fibers of the first layer and ρ optical fibers of the second layer. The signal combination shown in this figure corresponds to the control object located at the intersection of the a-th fiber of the first layer and the b-fiber of the second layer.

The first time diagram a) shows the signal T _{a-1 of} switching on the emitter number a-1, generated by the calculator 5. For this situation, the diagram P) shows the signal P (s, a-1), which represents the amplitudes of the photodetectors (1 ... ρ )

The timing diagram b) shows the signal T _{and the} inclusion of the emitter number u. For this situation, diagram f) shows the signal P (s, a), which represents the amplitudes of the same photodetectors (1 ... ρ), with a maximum at point a, i.e. when illuminating the object of control 6 by radiation of the a-th fiber of the first layer.

The time diagram c) shows the signal T _{a + 1} switching on the emitter number u + 1. For this situation, the signal P (s, а + 1) is shown in diagram g), which represents the amplitudes of the same photodetectors (1 ... ρ).

The timing diagram d) shows the signal T _{ω of} turning on the emitter number ω. For this situation, diagram h) shows the signal P (s, ω), which represents the amplitudes of the same photodetectors (1 ... ρ).

In FIG. 10 shows an example of the signal function P (s, u), for the control object 6.

Since the control object 6 is located closest to the optical fibers a and b of the first and second levels, respectively, the function P (s, u) has an extremum at the point (a, b).

Thus, to determine the position of the control object 6 relative to the first and second fiber layers, the calculator 5 enters the photodetector signals (1 ... ρ) for each emitter (1 ... ω) into memory and builds many functions:

where: P (s, u) is the amplitude of the signal of the s-th photodetector, with the u-th emitter turned on,

ω is the number of optical fibers of the first layer,

ρ is the number of optical fibers of the second layer;

The coordinates of the control object 6 can be determined from the equation:

where: s *, u * are the numbers of the optical fibers of the first and second layers, above which is the energy center of radiation of the control object 6.

If there is an object of complex shape over the light guide layers 1 and 2, for example, a hand with fingers facing the sensory tissue, in function (1), the function P (s, u) will have several local extrema, depending on the geometric arrangement of the fingers.

A geometric diagram of this situation is shown in FIG. eleven.

Finger fragments - 6 ₁ ... 6 ₅ , the tips of which are located at distances h ₁ , h ₂ , h ₃ , h ₄ , h ₅ from the sensory tissue 14 are highlighted on the wrist.

The magnitude of the reflected radiation from the surfaces 6 ₁ ... 6 ₅ depends on their reflectivity, and the illumination created by these emissions on the surfaces of the optical fibers also depends on the average distance to them. The signal values of the photodetectors 4 are shown in FIG. 12 and form the area:

P ¹ (s, u), P ² (s, u), P ³ (s, u), P ⁴ (s, u), P ⁵ (s, u),

corresponding to fragments 6 ₁ ... 6 ₅ .

Points of local extrema of the function P (s, u):

are characteristics of the position of object 6 relative to the optical sensory tissue, where n is the maximum number of local maxima of the function P (s, u).

When placing the optical sensor tissue on a reflective base 17, parasitic flare may occur due to re-reflection of the radiation of the optical fibers of the first layer towards the optical fibers of the second layer.

To avoid this, a third layer can be placed under the optical fibers of the second layer in the form of a woven strip absorbing the light flux formed by the first layer in the direction of the base.

In FIG. 13 shows the placement of the first 1 and second 2 layers over the woven strip 15. In this case, the woven strip 15 absorbs that part of the radiation Ф _a that is directed towards the base 17 and prevents its further reflection to the side of the optical fibers of the second layer 2. For attaching the optical fibers of the first and the second layer to the third layer uses a bonding fiber 16.

In addition, a third layer can be used that is opaque to the radiation generated by the first layer of fibers and placed between the first and second layers.

In FIG. 14 illustrates the placement of such a layer 18, made in the form of an opaque woven strip. The first and second layers intersect in separate sections, forming through intersections of the opaque woven strip 18. In this case, the radiation from the optical fibers of the first layer 1 can be reflected by the base 17, however, this radiation, due to the opaque woven strip 18, does not reach the optical fibers of the 2 layer.

To increase the mechanical strength and fix the location of the optical fibers of the first 1 and second 2 layers, their interweaving can be performed, as shown in FIG. fifteen.

In addition, the fastening of the optical fibers of the first and second layers can be carried out by their gluing. An illustration of such a method is shown in FIG. 16. It depicts a fragment of the optical sensory tissue, on which the intersection points of the optical fibers are fastened with an adhesive joint 19.

With a fairly close mutual arrangement of the optical fibers 1 of the first layer, the optical flux of the emitting optical fiber may penetrate into the adjacent optical fiber of the same layer. Further, the fiber into which this radiation has penetrated will partially re-emit it, including towards the control object 6, which may affect the accuracy of determining the position of the control object. To avoid this, at least one strand of material opaque to a given radiation located between adjacent optical fibers of the first layer can be additionally introduced.

The foregoing is illustrated in FIG. 17. Spurious radiation Pa _{, a + 1} , directed from the fiber 1 _{and the} side of the fiber 1 _{a + 1} , is blocked by a shielding fiber 19 made of optically opaque material. In this case, the shadow segment S _{a, a + 1} with a margin overlaps the fiber 1 _{a + 1} .

In FIG. 18 shows a fragment of an optical sensor tissue supplemented for greater effect by two radiation-shielding screening fibers 19.

To simplify the installation of optical sensor tissue, it is proposed to provide the possibility of combining the optical fibers of the first and second layers into a single bundle. Parallel arrangement of unused sections of optical fibers, i.e. those segments of optical fibers that do not create the orthogonal structure of the optical sensor layer with optical fibers of the second layer, leads to the penetration of polarized radiation from the surface of the first to the second. To avoid this, it is necessary to provide shielding of each fiber of the first layer with an opaque braid for radiation.

The foregoing is illustrated in FIG. 19. The presence of an opaque sheath 21 on the free portion 20 eliminates the penetration of polarized radiation from the side surface of the free portion of the fiber into the side surface of the second layer of optical fibers. The presence of an opaque braid 21 allows you to increase the distance from the optical sensor fabric 14 to the printed circuit board 22 with emitters 3 and photodetectors 4 installed on it.

To prevent mutual penetration of radiation received by the lateral surface of a particular fiber of the second layer into an adjacent fiber of the same layer, an opaque sheath may also be present in unused sections of the fibers of the second layer.

It is possible to increase the energy efficiency of optical sensor tissue by eliminating optical losses in unused sections of optical fibers, i.e. in the supply areas from the printed circuit board with emitters and photodetectors located on it to the location of the optical sensor tissue. Losses occur both in the optical fibers 1 of the first layer and in the optical fibers 2 of the second layer. In the first case, spurious radiation occurs not within the location of the sensor tissue, which reduces the power of the probe radiation. In the second case, radiation reflected by the test object to the side surface of the fiber within the sensor tissue is reradiated by the same surface during the propagation of radiation along the core of the fiber, decreasing the value of the signal recorded by the photodetector.

To eliminate these losses, the so-called end-face optical fibers [34] or the well-known single- or multimode telecommunication optical fibers can be used. In these fibers, the losses associated with the emission of their lateral surface are minimized.

In FIG. 20 illustrates the use of the first and second layers of end glow fibers 23 on unused sections of optical fibers. To weld the lateral glow fibers to the end glow fibers, a welded or adhesive joint, indicated by fragments 24, can be used.

To increase the power of the optical stream radiated towards the control object 6, groups of parallelly placed optical fibers of the first layer can be used, as shown in FIG. 21. Each group 25 of optical fibers 1 is optically coupled to a respective emitter 3. By increasing the effective area of the emitted surface, the power of the used emitters 4 can accordingly be increased.

An increase in the effective area of the optical fibers of the second layer gives a corresponding increase in sensitivity to radiation reflected from the control object 6. As shown in FIG. 22, for this, groups 26 of parallel placed optical fibers 2 of the second layer can be used.

In FIG. 23 shows an example of an optical sensor fabric with optical fibers placed in groups 25 and 26 in both the first and second layers.

To increase the efficiency of the optical sensory tissue, additional focusing as a probe, i.e. directed to the side of the possible position of the radiation control object, and radiation reflected from the control object.

For this, the so-called “lens array” (Lens Array) can be used, placed above the first and second layers of optical fibers, the center of each lens of which is perpendicular to the intersection area of optical fibers or their groups located in the first and second layers. The operation of such a coating is illustrated in FIG. 24, which depicts a single fragment thereof.

раз [35, формула 181].The presence of a lens 27 playing the role of an optical condenser with a focal length закреп _p fixed to the absorbing radiation of the optical fibers 1 of the support coating 28 increases the efficiency of the optical flow, i.e. increases the illumination of the optically coupled illuminated area [35, p. 138]. Namely, the luminous flux Ω _p , from the fragment σ, the surface of the optical fiber 1 of the first layer, is transformed by the lens 27 into the luminous flux Λ _p , which creates, on the surface of the test object 6, a spot σ _Λ with illumination greater than without a condenser in

times [35, formula 181].

To eliminate spurious reflections of the optical fluxes of the optical fibers 1, the support coating 28 should be made of a material that absorbs radiation, similar to an absorbent woven strip 15, but with a greater thickness determined by the focal length ƒ _{p of the} lens 27.

The image σ _{Λ of the} fragment σ is focused by the lens 27 on the surface of the light guide 2 of the second layer, in the form of a spot χ, partially blocked by the light guide 1.

In FIG. 25 shows a possible view of an optical sensor tissue using the “lens array” described above.

In order to exclude the influence of spurious illumination to which optical sensor tissue can be exposed, it is possible to use amplitude modulation (AM) of optical radiation, with corresponding processing of photodetector signals, using band-pass filtering of the useful signal against the background of interference.

This type of processing is widely used in remote infrared (IR) control systems for household appliances. These systems use infrared modulation, in which a pulse train is generated with a pulse frequency in the range of 30-56 kHz and 455 kHz. Photodetector microcircuits are produced for these frequencies, with an integrated transimpedance amplifier, a bandpass filter, an AGC and AM circuit detector [36, 37]. The detection rate of the useful signal for these microcircuits (t _don ), according to the manufacturer, is in the range of 15-36 μS.

For example, if the sensory tissue is formed by the intersection of 100 optical fibers of the first layer and 64 optical fibers of the second layer, it will take 100 cycles (1 for each fiber) to form bursts of a pulse sequence with a frequency of 455 kHz and a duration of 36 μS (when using the TSOP5700 IR photodetector). This gives an information update period of not more than 4 ms, i.e. frequency of 250 Hz.

The use of high-speed LEDs, PIN photodiodes, and modern digital radio receivers makes it possible to increase the frequency of updating information to tens to hundreds of megahertz, with a corresponding increase in the speed of the proposed optical sensor tissue device.

Information sources

1. US patent No. 6826968 B2 dated December 7, 2004.

2. US patent No. 7276137 B2 dated 02.10.2007

3. US Patent No. 8837952 B2 of September 16, 2014.

4. US patent No. 7630591 B2 dated 12/08/2009.

5. US Patent No. 7444887 B2 of 04/04/2008

6. US patent No. 7477816 B2 dated January 13, 2009.

7. US Patent No. 7627209 B2 of December 1, 2009.

8. US Patent No. 7496265 B2 of 02.24.2009

9. US Patent No. 7805036 B2 of September 28, 2010.

10. US patent No. 7817886 B2 of 10.19.2010.

11. US patent No. 7957615 B2 dated 06/07/2011

12. US Patent No. 8111958 B2 dated February 2, 2012.

13. US patent No. 7809221 B2 dated 05/10/2010.

14. US patent No. 8717330 B2 dated 05/06/2014

15. US patent No. 9164612 B2 of 10.20.2015.

16. US Patent No. 9127999 B2 of 09/08/2015.

17. US patent No. 9080918 B2 dated 06/14/2015

18. US patent No. 8826747 B2 of 09/09/2014.

19. US patent No. RE44856 E of 04/22/2014

20. US patent No. RE45578 E from 06.23.2015

21. US patent No. 8411140 B2 dated 02/02/2013.

22. Xiaoming Tao. Smart textile composites integrated with fiber optic sensors. Smart fibers, fabrics and clothing. Edited by Xiaoming Tao. Woodhead Publishing Ltd and CRC Press LLC, 2001.

http://textilelibrary.weebly.com/uploads/1/1/7/4/11749432/smart_fibres_fabrics_and_clothing_xiaoming_tao_2001.pdf

23. Winger, J.G., Kok-Meng Lee. Experimental investigation of a tactile sensor based on bending losses in fiber optics. 1988 IEEE International Conference on Robotics and Automation, Philadelphia, PA, Apr. 24-29, 1988, Proceedings. Volume 2 (A89-1190102-63). Washington, DC, Computer Society Press, 1988, p. 754-759. Research supported by Georgia Institute of Technology.

http://adsabs.harvard.edu/abs/1988roau....2..754W

24. D.T. Jenstrom, Chen-Lin Chen (1989) A fiber optic microbend tactile sensor array. Sensors and Actuators, Volume 20, Issue 3 (1 December 1989), Pages 239-248.

http://www.sciencedirect.com/science/article/pii/0250687489801222

25. K.T.V. Grattan, Z.Y. Zhang, T. Sun. Luminescent optical fibers in sensing. Optical Fiber Sensor Technology Volume 4 of the series Optoelectronics, Imaging and Sensing. 1999, pp. 205-247.

http://link.springer.com/chapter/10.1007%2F978-94-017-2484-5_8

26. D. Kremenakova, J. Militky, B. Meryova, V. Ledl. Characterization of Side Emitting Polymeric Optical Fiber. Journal of Fiber Bioengineering & Informatics, 2012, 5 (4): 423-431.

http://www.jfbi.org/EN/abstract/abstract17.shtml#

27. S.A. Kuznetsov, V.V. Kubarev, P.V. Kalinin, B.G. Goldenberg, V.S. Eliseev, E.V. Petrova, N.A. Vinokurov. Development of metal based quasi-optical selective components and their application in high-power experiments at Novosibirsk terahertz FEL. Proceedings of FEL 2007, Novosibirsk, Russia.

https://accelconf.web.cern.ch/accelconf/f07/PAPERS/MOPPH032.PDF

28. Arindam Das, Thomas M. Schutzius, Constantine M. Megaridis, Subhali Subhechha, Tao Wang, and Lei Liu. Quasi-optical terahertz polarizers enabled by inkjet printing of carbon nanocomposites. Applied Physics Letters 101, 243108 (2012).

http://scitation.aip.org/content/aip/journal/apl/101/24/10.1063/1.4770368

29. Technical publication of Thorlabs Inc., USA. Wire Grid Polarizers on Glass Substrates.

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=5510

30. Technical publication of TYDEX, RF. IR polarizers.

http://www.tydexoptics.com/pdf/en/IR_polarizers.pdf

31. US patent No. 6208463 from 05/27/2001

32. G.S. Landsberg. Optics. Textbook: for universities. 6th ed. Moscow. Fizmatlit, 2003

33. F. Crawford. Waves: A tutorial: Per. from English 3rd ed., Rev. Moscow. Science, 1984 (Berkeley Physics Course). - 512 s.

34. Technical publication of Mica Lighting Company, Inc 717 S. State College Blvd., Fullerton, USA. End light multi-strand fiber optic cable.

http://www.micalighting.com/PDFs/fiber_optics/MICA%20%20Lighting%20-%20FO%20Fiber%20-%20End%20Light.10.pdf

35. I.L. Sakin. Engineering optics. Leningrad. Engineering, 1976 - 288 pages

36. Technical Publication of Vishay Intertechnology, Inc. USA

http://www.mouser.com/ds/2/427/tsop62-346044.pdf

37. Technical publication of Vishay Intertechnology, Inc. USA

http://datasheet.octopart.com/TSOP5700TR-Vishay-datasheet-91528.pdf

Claims (18)

1. The device of an optical sensor tissue consisting of two mutually perpendicular layers of optical fibers, the core of the optical fibers of the first layer being optically connected to a set of emitters connected to the outputs of the computing device, and the optical core of the second layer being optically connected to a set of photodetectors connected in turn to the input a computing device, characterized in that a polarizing coating is applied to the outer surfaces of the optical fibers of both layers so that the radiation from the surface of the first optical fibers layer, acquiring the polarized property, propagating to the control object, partially reflecting from it and losing the polarization property, falls on the side surface of the fibers of the second layer and then propagates through their cores to the respective photodetectors, while the computing device sequentially turns on each emitter, reads the signals photodetectors and their values determines the position of the control object, while the radiation incident directly on the side surfaces of the optical fibers of the second loya from the optical fibers of the first layer is quenched by its polarizing coating. 2. The device of the optical sensor tissue according to claim 1, characterized in that the optical fibers of both layers are made on the basis of lateral optical fiber. 3. The device of the optical sensor tissue according to claim 2, characterized in that a polarizing coating is applied to the lateral surface of the optical fibers, the structure of which is symmetrical about the optical axis of the optical fiber. 4. The device of the optical sensor tissue according to claim 2 or 3, characterized in that a polarizing coating in the form of metallized strips parallel to its center line is applied to the lateral surface of the optical fibers. 5. The device of the optical sensor tissue according to claim 2 or 3, characterized in that a polarizing coating in the form of metallized strips perpendicular to its center line is applied to the lateral surface of the optical fibers. 6. The device of the optical sensor tissue according to claim 2 or 3, characterized in that a polarizing coating in the form of triangular notches parallel to its center line is applied to the lateral surface of the optical fibers with metallization applied to one of their faces. 7. The device of the optical sensor tissue according to claim 2 or 3, characterized in that a polarizing coating in the form of triangular notches perpendicular to its center line is applied to the lateral surface of the optical fibers with metallization applied to one of their faces. 8. The device of the optical sensor tissue according to claim 1, characterized in that it comprises a third layer made of optically absorbing radiation material, for example, a fabric placed under the second layer, the first layer being placed on the side facing the control object. 9. The device of the optical sensor tissue according to claim 1, characterized in that between the first and second layers there is a third layer representing a material that is optically opaque to radiation, for example woven, the first and second layers intersecting in separate areas, forming through intersections of the third layer. 10. The device of the optical sensory tissue according to claim 1, characterized in that the first and second layers are intertwined and form a woven structure. 11. The device of the optical sensor tissue according to claim 1, characterized in that between the optical fibers of the first layer, at least one fiber is laid that is opaque to the radiation formed on their side surfaces. 12. The device of the optical sensor tissue according to claim 1, characterized in that a part of the surface of the optical fibers of the first layer is covered with an opaque braid. 13. The device of the optical sensor tissue according to claim 1, characterized in that a part of the surface of the optical fibers of the second layer is coated with an opaque braid. 14. The device of the optical sensor tissue according to claim 1, characterized in that between the ends of the optical fibers of the first layer and the emitters is an optical fiber of the end glow coupled to them. 15. The device of the optical sensor tissue according to claim 1, characterized in that between the ends of the optical fibers of the second layer and the photodetectors is an optical fiber of the end glow coupled to them. 16. The optical sensor tissue device according to claim 1, characterized in that each emitter is optically coupled to more than one light guide of the first layer. 17. The optical sensor tissue device according to claim 1, characterized in that each photodetector is optically coupled to more than one second layer optical fiber. 18. The device of the optical sensor tissue according to claim 1, characterized in that it further comprises a radiation-absorbing coating with openings over the intersection points of the optical fibers of the first and second layers and lenses fixed above them, concentrating the radiation of the optical fibers of the first layer and focusing the light flux reflected from the control object optical fibers of the second layer.

Images