JPS62170116A - Optical fiber mat - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical fiber mat, and more particularly to an optical fiber cloak having optical fibers therein.

(Prior Art) Conventionally, far-infrared sensors, ultrasonic sensors, radars, rubber mats, and the like have been widely used as sensors for intrusion detectors, automatic doors, and the like.

Far-infrared sensors use an optical system to focus far-infrared rays emitted from the human body onto a pyroelectric element and detect them using a differential effect. Ultrasonic sensors send ultrasonic waves toward a moving object, It uses the Doppler effect with the reflected waves, measures the time it takes for the waves to return, and detects moving objects based on changes in distance above the floor.

Additionally, radar emits gigahertz-level radio waves and uses the Doppler effect with reflected waves reflected from moving objects.Rubber mat sensors have electrical contacts inside the rubber mat, and are normally in a broken state. When a person walks on it, the pressure causes the contacts to close, creating an electrical circuit.

(Problem to be solved by the invention) However, far-infrared sensors tend to malfunction due to the effects of high summer temperatures, sunlight, and car headlights at night.
Ultrasonic sensors have problems in that the directivity is not very sharp, so the boundary between the sensing area and the non-sensing area is not clear, that adjustments are difficult to make when setting up the device, and that there are many disturbance factors.

Radar sensors also have the Doppler effect, but they also suffer from sharp dust and the boundaries between the sensing area and other areas are blurred, making adjustment difficult.

Rubber mat sensors have clear boundaries, but the on/off function of the contacts inside the cloak deteriorates with repeated use, and since electricity flows through the mat, when water or the like hits the floor, There is a risk of electrical leakage or electric shock.

The present invention addresses malfunctions caused by disturbance factors in conventional sensors used in intrusion detectors and automatic doors as described above.
In addition to eliminating ambiguity in the boundary with the sensing area, <
The purpose is to solve problems such as functional deterioration due to the use of nine barbs, as well as the risk of electrical leakage and electric shock.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides the following optical fiber mat.

That is, the present invention fixes two optical fibers formed in a meandering shape on a lower surface protection member, covers the optical fibers with an upper surface protection member, and connects the upper surface protection member to the lower surface protection member. 9, the two optical fibers are a pressure-sensitive optical fiber with an outer diameter D1 and a temperature-compensating optical fiber with an outer diameter D2, and DI and D
This is an optical fiber mat characterized by a size relationship of >02.

(Function) When pressure is applied from above the optical fiber mat configured in this way, the outer diameter of the two optical fibers, Dl
Pressure is applied to the optical fiber D2, which has a smaller outer diameter, and the pressure is set to be either not applied at all or to a negligible extent even if it is applied.

Therefore, the optical fiber with the outer diameter D1, which is more susceptible to pressure, has a large strain and generates scattered light with respect to the incident light, and the amplitude of the output light becomes small, but the optical fiber with the smaller outer diameter D2 Almost no distortion occurs, and the emitted light does not change. Therefore, the difference between the two can be calculated as a differential effect.

However, changes in ambient temperature affect the two optical fibers equally or proportionally, so they can be canceled out by electrical circuit processing, so changes in temperature do not appear externally as voltage. .

In other words, two optical fibers with different outer diameters are used to provide a pressure sensor function and a temperature compensation function.

(Example) Regarding an example of the present invention, how the configuration of the present invention is actually embodied will be described below with reference to the drawings, along with its operation.

FIG. 1 is an explanatory plan view of one embodiment of the present invention, with a portion cut away.

Reference numeral 1 denotes an optical fiber mat main body, which includes a lower surface protection member 2 made of a P tile or a rubber plate, and two optical fibers fixed on this lower surface protection member 2, namely a pressure-sensitive optical fiber 3 with an outer diameter D1 and an outer diameter D1. It is composed of temperature compensating optical fibers 4 of D2 and an upper surface protection member 5 such as a carpet which covers these optical fibers and is attached to a lower surface protection member with Velcro, and a control circuit box 6 is attached to this.

Here, the outer diameter refers to the outermost diameter including the coating, and if there is no coating, it refers to the outer diameter of the cladding.

The relationship between the sizes of D and D2 is D+>02, and the outer diameter D1 of the pressure-sensitive optical fiber 3 is larger than the outer diameter D2 of the temperature-compensating optical fiber 4.

The pressure-sensitive optical fiber 3 and the temperature-compensating optical fiber 4 are arranged in parallel in a meandering manner.

In order to maintain good light transmission characteristics, these two optical fibers are formed in a meandering shape to avoid sharp bends.

The control circuit box 6 incorporates a mutual conversion function between light and electricity and other electrical processing circuits.

FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1, in which a pressure-sensitive optical fiber 3 with a large external shape, that is, a large external shape, and a temperature compensating optical fiber 4 with a small external shape D2 are placed on the lower surface protection member 2. are fixed with an adhesive 7, covered with an upper surface protection member 5, and the upper surface protection member 5 is attached to the lower surface protection member 2 with an attachment member 8 such as Velcro.

Although the attachment member 8 is a removable Velcro tape in the figure, it may be a zipper, or it may be fixedly attached using an adhesive.

When pressure P is applied due to a person walking on the optical fiber cloak main body 1, pressure P is applied to the pressure-sensitive optical fiber 3, which has a thick outer diameter, through the upper surface protection member 5, and the core is deformed. The optical transmission characteristics change.

At this time, the temperature compensating optical fiber 4, which is formed to have a thin outer diameter D2, is set so that no pressure is applied to it at all, or it is so small that it can be ignored. By doing so, the optical transmission characteristics of the temperature compensating optical fiber 4 do not change even when the temperature compensating optical fiber 4 is walked on the cloak.

Note that, in the figure, the core and cladding are not particularly shown separately for convenience.

FIG. 3 shows an embodiment of a pressure-sensitive optical fiber 3 having a large outer diameter and an optical fiber 4 having a small outer diameter from two sides.

First, FIG. 3A shows the case where both optical fibers 3 and 4 have no coating. The outer diameter D1 is the pressure sensitive optical fiber 3, and the outer diameter D2 is the temperature compensation optical fiber 4.
I'll go. This indicates that the larger the outer diameter is, the more susceptible to the influence of pressure P.

Note that both optical fibers are arranged in parallel so that changes in ambient temperature are affected equally or proportionally.

FIG. 3B shows another embodiment in which a pressure-sensitive optical fiber with an outer diameter D1 has a coating 3a, and a temperature-compensating optical fiber 4 with an outer diameter D2.
shows the case where there is no coating.

FIG. 3C shows still another example, in which the pressure-sensitive optical fiber 3 and the temperature-compensating optical fiber 4 each having an outer diameter D1 have fi 3a and fi 4a. In either case, the outer diameter of the pressure-sensitive optical fiber 3 is made larger than the outer diameter D2 of the temperature-compensating optical fiber 4, thereby increasing the pressure sensitivity of the pressure-sensitive optical fiber 3 and adjusting the temperature compensation. This is to reduce the pressure sensitivity of the optical fiber 4.

FIG. 4 is an explanatory diagram of the control circuit box 6.

Driven by a driving source 9, a light emitting element 10 emits an optical signal of a constant intensity. In the figure, there is one light emitting element 10, but two light emitting elements 10 may be provided to correspond to the respective fibers 3 and 4.

This optical signal enters from the end faces of the pressure-sensitive optical fiber 3 and the temperature-compensating optical fiber 4, and enters the optical fiber mat main body 1.
The signals exit from the other end of the optical fiber and are converted into electrical signals by the light receiving elements 11 and 12.

The light receiving element 11 receives the light emitted from the pressure sensitive optical fiber 3,
A voltage El is generated between both ends a''c of the fixed resistor R1.

Still, the light receiving element 12 receives the light emitted from the temperature compensating optical fiber 4 and generates a voltage E2 between both ends b and c of the variable resistor R2.

Since the light-receiving elements 11 and 12 are coupled so that their polarities are in opposite directions, E and E2 are also polarized in opposite directions, so that a voltage E is taken out between terminals a and b. is E
, and Et.

Therefore, adjust the variable resistor R2 so that E,=E,1. Then, Eo '' F21E2 = 0, and the voltage E that normally appears between terminals a and b.

is 0, that is, it maintains an equilibrium state with no voltage.

When pressure is applied to the optical fiber mat main body 1, the output light of the pressure-sensitive optical fiber 3 decreases due to the above-mentioned reason, and the voltage at both ends of the light receiving element 11, that is, at both ends of the resistor R7 is reduced by E, to E P + . It becomes El EP+.

At this time, the temperature compensation optical fiber 4 receives almost no pressure,
Therefore, since the emitted light does not decrease, the voltage change E appearing across both ends of the light receiving element 12, that is, across the variable resistor R2.
The amount of change in P2 can be ignored as E p2″:O, and the voltage E2 is Et
Epz#E2 0:Et remains unchanged.

Therefore, the voltage E between terminals a and b. The balance is lost, and Eo ” (El E p+) Et ”El
Et-Ep+ = OEp+ = EP+, and only the change on the E1 side -E p+ appears, and the change in pressure can be taken out as a change in voltage.

Next, the amount of change in the voltage across each of the light receiving elements 11 and 12 due to the change in the ambient temperature of the optical fiber cloak body 1 is E t, -E
As for t2, since both optical fibers are arranged in a meandering manner in parallel, they are affected by temperature changes almost equally or proportionally, and can be adjusted by variable resistor R2, so Et+ = Et2, that is, Et , -Et2=0, and the voltage E between terminals a and b. (El
−Et+ )−(E, −Et2 )=(El −Et
)−(Et, −Et2), and substituting the above E, −Et =0 and Et, −Et 2 =0, we get (El −Et )−1t, −Et2): 0−0=0. Therefore, the voltage E between terminals a and b. is not affected by the ambient temperature, indicating that the optical fiber mat with this configuration has a temperature compensation function.

The configurations of the embodiments of the present invention have been described above, but the present invention includes a pressure-sensitive optical fiber 3 formed with a thick outer diameter and a temperature-compensating optical fiber 4 formed with a thin outer diameter D2. are provided in parallel in the mat, so that the change in the transmission characteristics of only the pressure-sensitive optical fiber 3 is mainly extracted in response to pressure, and the change in the transmission characteristics of both pressure sensitive optical fibers is equal or proportional to changes in temperature. This is a temperature-compensated optical fiber mat that takes advantage of this phenomenon and cancels it out with an electric circuit to constantly eliminate the effects of temperature.

(Effects of the Invention) In the present invention, pressure-sensitive optical fibers having a thick outer diameter and optical fibers having a thin outer diameter D2 are arranged in a meandering manner within a mat. The thicker pressure-sensitive optical fiber with outer diameter D2 feels the pressure more sensitively, and the thinner temperature-compensating optical fiber with outer diameter D2 feels little or no pressure, so changes in pressure are detected due to its unbalance. It can be a pressure sensor.

In addition, since changes in temperature always appear as changes in the transmission characteristics of both optical fibers equally or proportionally, a temperature-compensated type that eliminates the effects of temperature changes by canceling them in an electric circuit is used. An optical fiber mat can be obtained.

[Brief explanation of drawings]

FIG. 1 is an explanatory plan view of one embodiment of the present invention, and FIG.
A cross-sectional view taken along the line A-A in the figure, and FIG. 3 are diagrams showing embodiments of the pressure-sensitive optical fiber and temperature-compensating optical fiber of the present invention.
A indicates one embodiment, B indicates another embodiment, and C indicates still another embodiment. FIG. 4 is an explanatory diagram of the circuit control box. (In the figure) 2 - Lower surface protection member 3 - Pressure-sensitive optical fiber 4 - Temperature compensation optical fiber 5 - Upper surface protection member Patent applicant Honda Electronic Gikentsu Co., Ltd. 1 Figure 2

Claims (6)

[Claims] (1) An optical fiber formed by fixing two optical fibers formed in a meandering shape on a bottom protection member, covering the top with a top protection member, and attaching the top protection member to the bottom protection member. In the mat, the two optical fibers include a pressure-sensitive optical fiber with an outer diameter D_1 and a temperature-compensating optical fiber with an outer diameter D_2, and the relationship between D_1 and D_2 is D_1>D_2. fiber mat. (2) The optical fiber mat according to claim 1, wherein both of the two optical fibers have no coating. (3) The optical fiber mat according to claim 1, wherein the pressure-sensitive optical fiber has a coating and the temperature-compensating optical fiber does not have a coating. (4) The optical fiber mat according to claim 1, wherein both of the two optical fibers have a coating. (5) The optical fiber mat according to claim 1, wherein the upper surface protection member is detachably attached to the lower surface protection member. (6) The optical fiber mat according to claim 1, wherein the upper surface protection member is fixedly attached to the lower surface protection member.