CN105650550A - Indoor optical fiber coupling LED auxiliary illumination system and manufacturing method thereof - Google Patents

Abstract

The invention discloses an indoor optical fiber coupling LED auxiliary illumination system and a manufacturing method thereof. The system comprises an LED light source, a cooling fin and an illumination optical fiber. The LED light source is connected to the cooling fin. The incidence end and the exit end of the illumination optical fiber are conical. Light emitted by the LED light source is coupled in the illumination optical fiber from the incidence end to be transmitted and is emitted from the exit end. By conducting fused biconical taper processing on the incidence end of the illumination optical fiber, the divergent light rays emitted by an LED are more effectively coupled with the optical fiber, and the light energy utilization rate is increased; by conducting fused biconical taper processing on the exit end of the illumination optical fiber, the angle of light rays emitted by the optical fiber is increased, the illumination range is widened, and the system further meets actual requirements.

Description

A kind of indoor optical fiber coupling LED auxiliary lighting system and preparation method thereof

Technical field

The present invention relates to optical fibre illumination application, be specifically related to the novel auxiliary lighting system that a kind of near-infrared LED lamp combines with optical fiber.

Background technology

Active night vision technology, by increasing auxiliary lighting system, actively launches near-infrared light beam to object, improves the flashlight energy of return, thus obtaining the detailed information of object scene under low-visibility conditions, has the advantages such as definition height, economy is reliable. Semiconductor light-emitting-diode (LED) is a kind of novel semiconductor illuminating light source, has long service life, the advantage such as energy-efficient, is the widely used active illumination light source of current protection and monitor field.

Optical fibre illumination technology is as what the development of optic fibre manufacturing technology and electric light source technology was arisen at the historic moment, its ultimate principle is to be optically coupled into optical fiber by coupling device what light source sent, utilize the principle conduction light that light carries out being totally reflected in optical fiber, thus being illuminated. Owing to optical fiber material has only guide-lighting non-conductive, the advantage such as volume is little, pliability is strong, obtain in the field such as industrial, medical and paid close attention to widely and application.

Compared in current safety monitoring, widely used near-infrared LED light source is made directly floor light, the optical fiber auxiliary lighting system that active night vision technology combines with optical fibre illumination technology is had photodetachment, flexible, without features such as electromagnetic interference, can be advantageously mounted in multiple lighting environment or object, the floor light of the round-the-clock monitoring in the field such as security protection, public security can be efficiently applied to, and this system disguise is relatively strong, have irreplaceable advantage in special lighting field. Tradition near-infrared fibre-optical auxiliary lighting system many employings near-infrared laser is as light source, and to obtain high light fibre emergent power, but when adopting laser as light source, beam exit angle is little, is only applicable to floor light at remote night. After considering optical fibre illumination and the respective advantage of LED light source, optical fiber coupling LED auxiliary lighting system can farthest realize their complementation. But, owing to LED light-emitting area is relatively big, and the radiation angle of divergence is big, relatively low with the coupling efficiency of optical fiber, limits its application at lighting field. Generally, the method improving coupling efficiency is that the light launched by light source by optical element carries out beam shaping, it is made to meet the numerical aperture of optical fiber, this optical element can be lens, lens combination, or the total reflection device of particular process, but when LED light source light-emitting area is bigger, its main coupling loss is area mismatches loss, adopts this kind of coupled modes and cannot be effectively improved coupling efficiency.

Summary of the invention

For the deficiencies in the prior art, it is desirable to provide a kind of indoor light coupling LED auxiliary lighting system, by being specifically designed lighting fiber, its two ends are carried out fused biconical taper process, increase fiber numerical aperture, both improved coupling efficiency, optical fiber light radiation angle can be increased again, better meet the functional need of indoor floor light, and compact, with low cost.

To achieve these goals, the present invention adopts the following technical scheme that

A kind of indoor optical fiber coupling LED auxiliary lighting system, including LED light source and lighting fiber; The incidence end of described lighting fiber and exit end are all tapered, and the light that described LED light source sends is coupled into lighting fiber from described incidence end and is transmitted and penetrates from exit end.

As a kind of preferred version, also including fin, described LED light source is connected to one end of described fin.

All it is tapered along optical axis as further preferred version, the incidence end of described lighting fiber and the diameter of exit end place covering and fibre core.

As further preferred version, in the whole cone district of incidence end and exit end, the diameter ratio of covering and fibre core keeps constant.

As a kind of preferred version, also including optical fiber fixed port, the incident end face of described lighting fiber is arranged on against LED light source exit positions place by described light fixed port.

As a kind of preferred version, described LED light source is single near-infrared LED light source, and the near-infrared black light that described LED light source sends is coupled into lighting fiber from described incidence end and is transmitted and penetrates from exit end. " red sudden and violent " phenomenon when adopting near-infrared LED light source can avoid this system for the floor light of the round-the-clock monitoring in the field such as security protection, public security, improves the disguise of illumination.

As further preferred version, the centre wavelength of described near-infrared LED light source is 940nm.

As a kind of preferred version, when LED light source light-emitting area is less than lighting fiber incidence end area, described LED light source is coupled with lighting fiber incidence end by coupling device.

The manufacture method of above-mentioned indoor optical fiber coupling LED auxiliary lighting system comprises the steps:

Lighting fiber incidence end and exit end, according to structural parameters set in advance, are carried out fused biconical taper process so that described incidence end and exit end are tapered by S1;

LED light source is installed on one end of described fin by S2, and is installed on the incidence end of described lighting fiber against LED light source exit positions place by described optical fiber fixed port.

It should be noted that in step S1, the determination step of described structural parameters is as follows:

According to the ray theory accurate analysis light transmission characteristic at lighting fiber end, draw the relation of incidence end cone angle and incidence end aperture angle of incidence and exit end cone angle and exit end light radiation angle, determine one group of lighting fiber structural parameters making incidence end aperture angle of incidence and exit end light radiation angle try one's best big, wherein, described incidence end aperture angle of incidence represents that optical fiber accepts and transmits the ability of light, and on incident end face, incident angle all can enter spread fiber less than the light beam of this aperture angle of incidence; Described exit end light radiation angle represents can from the refraction angle corresponding to the light becoming maximum angle with optical fiber central axis of outgoing end face outgoing:

Take the incidence angle �� of light L1, a L1₀Being not provided with, equal to incidence end and the exit end when lighting fiber, the maximum aperture angle that tapering is correspondence, refraction angle is ��₀, L1 and lighting fiber side intersection point are the point of intersection of the side of the tapered end of the fibre core of lighting fiber and straight line portion side;

The incidence of lighting fiber end face same point and angle of incidence are less than ��₀Arbitrary light L2, be directly entered optical fiber normal propagation without incidence end offside reflection, and angle of incidence be more than ��₀Light, need to reflect through incidence end, if its angle of reflection is be more than or equal to lighting fiber critical angle, can propagate in lighting fiber; Take another light L3, angle of incidence be ��, L3 after incidence end offside reflection, its angle of reflection be equal to lighting fiber critical angle, therefore angle of incidence is more than ��₀And the arbitrary light less than or equal to �� all can meet propagation conditions after incidence end offside reflection, that is the angle of incidence arbitrary light less than or equal to �� can both enter described lighting fiber and in a fiber with less loss propagation, and �� is the aperture angle of incidence of described incidence end;

The cone length of described lighting fiber is h, and after lighting fiber fused biconical taper, the minimizing amount of fiber end face radius is y, and the incident tapered end diameter of lighting fiber is d, and when lighting fiber two ends are not provided with tapered, core diameter is l, then incidence end semi-cone angle �� is obtained by following formula:

$\left\{\begin{array}{c}\frac{y}{tan\mathrm{\α}}=\frac{y+d}{{\mathrm{tan\φ}}_0}=h\\ d+2y=l\end{array}\right.;$

Make the angle of reflection of light L3Equal to lighting fiber critical angle ��_c, ��_c=arcsin (n₂/n₁), utilize the law of refraction, obtain the incidence end aperture angle of incidence �� of described lighting fiber:

In formula, n₀Medium refraction index residing for lighting fiber, n₁For lighting fiber fiber core refractive index, n₂For lighting fiber cladding index;

The kind of the pattern can propagated in optical fiber and quantity can be described by lighting fiber normalized parameter R:

$R=\frac{2\mathrm{\π}r}{\mathrm{\λ}}\sqrt{n_1^2-n_2^2};$

In formula, r is lighting fiber fiber core radius, �� is wavelength, R value is more big, propagable pattern is more many, and namely in described lighting fiber, propagable pattern both depends on the R value of its small end, therefore, when the core diameter d of described lighting fiber incidence end is less than or equal to the core diameter of described lighting fiber exit end, can make to be coupled into light all effectively outgoing of described optical fiber;

Considering area mismatches loss when coupling, the incidence end core diameter d of described lighting fiber should try one's best greatly; Additionally, according to path reversal principal, when exit end cone angle is equal to incidence end cone angle, incidence the uniform light outgoing propagated in a fiber can be made, better illuminating effect can be reached, therefore the described incidence end of lighting fiber and the tapered end structural design of exit end are symmetrical structure, now, the light radiation angle of the exit end of described lighting fiber is equal to the aperture angle of incidence �� of incidence end.

The beneficial effects of the present invention is:

Optical fibre illumination technology is combined with active night vision technology, can be applicable to the floor light of the field such as security protection, public security all-weather electronic monitoring, for carrier, monitoring region is illuminated with optical fiber, it is achieved the raising of electronic monitoring picture quality under dark situation. Owing to optical fiber volume is small, pliability strong, system can be advantageously mounted in indoor various environment occasion or narrow space. The present invention, by the fused biconical taper of lighting fiber incidence end is processed, makes the LED divergent rays sent more effectively couple with optical fiber, improves the efficiency of light energy utilization; By the exit end of lighting fiber is carried out fused biconical taper process, make fiber exit light angle increase, expand illumination zone, further conform to functional need.

Accompanying drawing explanation

Fig. 1 is the structural representation of optical fiber of the present invention coupling LED auxiliary lighting system.

Fig. 2 is the taper incidence end structural parameters schematic diagram of lighting fiber in Fig. 1.

Fig. 3 is lighting fiber structural representation in Fig. 1.

Fig. 4 is the expansion structure schematic diagram of optical fiber of the present invention coupling LED auxiliary lighting system.

Detailed description of the invention

Below with reference to accompanying drawing, the invention will be further described, it is necessary to explanation, and the present embodiment, premised on the technical program, gives detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to the present embodiment.

As shown in Figure 1, the present invention is a kind of indoor optical fiber coupling LED auxiliary lighting system, it includes fin 1, LED light source 2, optical fiber fixed port 3, also include the lighting fiber 4 being placed in optical fiber fixed port 3, wherein LED light source 2 is arranged on one end of fin 1, and the incident end face of lighting fiber 4 is placed against the exit positions of LED light source 2 by optical fiber fixed port 3.

Fig. 2 is the taper incidence end structural parameters schematic diagram of described lighting fiber 4, when light is incident to optical fiber small end with �� angle, after refraction, and the fibre core-clad interface of directive tapered end side, can obtain according to triangle geometrical relationship and catadioptric law:

In formula, �� is the semi-cone angle of described lighting fiber, and n is at the light order of reflection in tapered end side,Represent refraction angle.

Known, when light is propagated to big end by the small end of the taper incidence end of described lighting fiber 4, light reflection angle on fibre core-clad interface is gradually increased with the increase of order of reflection, namely increasing in critical angle at the angle of incidence of fibre core-clad interface, major part energy concentrates on fibre core and propagates. Therefore, as long as disclosure satisfy that the incident ray at the small end numerical aperture angle of described lighting fiber 4 taper incidence end, big end can be delivered to relatively low loss. Otherwise, when light is propagated to exit end small end by the big end of exit end, light angle of incidence on fibre core-clad interface reduces with the increase of order of reflection, and total reflection condition is easily destroyed, it is easy to cause energy leakage. To sum up analyzing, described lighting fiber 4 can change fiber numerical aperture NA and optical fiber light radiation angle.

The structural parameters of described conical illumination optical fiber 4 are determined as follows:

According to the ray theory accurate analysis light transmission characteristic at lighting fiber end, draw the relation of incidence end cone angle and incidence end aperture angle of incidence and exit end cone angle and exit end light radiation angle, determine one group of lighting fiber structural parameters making incidence end aperture angle of incidence and exit end light radiation angle try one's best big, wherein, described incidence end aperture angle of incidence represents that optical fiber accepts and transmits the ability of light, and on incident end face, incident angle all can enter spread fiber less than the light beam of this aperture angle of incidence; Described exit end light radiation angle represents can from the refraction angle corresponding to the light becoming maximum angle with optical fiber central axis of outgoing end face outgoing:

As in figure 2 it is shown, take the incidence angle �� of light L1, a L1₀Being not provided with, equal to incidence end and the exit end when lighting fiber, the maximum aperture angle that tapering is correspondence, refraction angle is ��₀, L1 and lighting fiber side intersection point are the point of intersection A of the side of the tapered end of the fibre core of lighting fiber and straight line portion side;

The incidence of lighting fiber end face same point and angle of incidence are less than ��₀Arbitrary light L2, be directly entered optical fiber normal propagation without incidence end offside reflection, and angle of incidence be more than ��₀Light, need to reflect through incidence end, if its angle of reflection is be more than or equal to lighting fiber critical angle, can propagate in lighting fiber; Take another light L3, angle of incidence be ��, L3 after incidence end offside reflection, its angle of reflection be equal to lighting fiber critical angle, therefore angle of incidence is more than ��₀And the arbitrary light less than or equal to �� all can meet propagation conditions after incidence end offside reflection, that is the angle of incidence arbitrary light less than or equal to �� can both enter described lighting fiber and in a fiber with less loss propagation, and �� is the aperture angle of incidence of described incidence end;

The cone length of described lighting fiber is h, and after lighting fiber fused biconical taper, the minimizing amount of fiber end face radius is y, and the incident tapered end diameter of lighting fiber is d, and when lighting fiber two ends are not provided with tapered, core diameter is l, then incidence end semi-cone angle �� is obtained by following formula:

$\left\{\begin{array}{c}\frac{y}{tan\mathrm{\α}}=\frac{y+d}{{\mathrm{tan\φ}}_0}=h\\ d+2y=l\end{array}\right.;$

Make the angle of reflection of light L3Equal to lighting fiber critical angle ��_c, ��_c=arcsin (n₂/n₁), utilize the law of refraction, obtain the incidence end aperture angle of incidence �� of described lighting fiber:

In formula, n₀Medium refraction index residing for lighting fiber, n₁For lighting fiber fiber core refractive index, n₂For lighting fiber cladding index;

The kind of the pattern can propagated in optical fiber and quantity can be described by lighting fiber normalized parameter R:

In formula, r is lighting fiber fiber core radius, �� is wavelength, R value is more big, propagable pattern is more many, and namely in described lighting fiber, propagable pattern both depends on the R value of its small end, therefore, when the core diameter d of described lighting fiber incidence end is less than or equal to the core diameter of described lighting fiber exit end, can make to be coupled into light all effectively outgoing of described optical fiber;

Considering area mismatches loss when coupling, the incidence end core diameter d of described lighting fiber should try one's best greatly; It addition, according to path reversal principal, when exit end cone angle is equal to incidence end cone angle, incidence the uniform light outgoing propagated in a fiber can be made, better illuminating effect can be reached, therefore the tapered end structural design of the incidence end of described lighting fiber and exit end is symmetrical structure, as shown in Figure 3. Now, the light radiation angle of the exit end of described lighting fiber is equal to the aperture angle of incidence �� of incidence end.

In the present embodiment, select OSRAMSFH4233 as near-infrared LED light source, its light-emitting area diameter is 1mm, for avoiding area mismatches loss during coupling light source and optical fiber, design the taper incidence end tapered end core diameter d=1mm of described lighting fiber 4, i.e. the exit end tapered end core diameter d '=d=1mm of required lighting fiber 4. In the present embodiment, select the large aperture polymer optical fiber of numerical aperture NA=0.5 as lighting fiber 4, fiber core refractive index n₁=1.492, cladding index n₂=1.402, medium residing for optical fiber is air, i.e. n₀=1, then the aperture angle of incidence of this flush end optical fiber is 30 ��. Table 1 is according to above-mentioned analysis, calculates the cone angle after the different core diameter flush end optical fiber fused taperings that gained is common and aperture angle of incidence.

Table 1

Flush end core diameter l

2mm

3mm

4mm

5mm

6mm

7mm

8mm

9mm

Cone angle

6.76��

10.08��

12.05��

13.34��

14.26��

15.46��

15.88��

16.23��

Aperture angle of incidence ��

42.21��

48.41��

52.35��

55.09��

57.13��

58.70��

59.96��

60.99��

The above results explanation, by optimizing design lighting fiber, cone is drawn to process at its two ends, flush end optical fiber input angular aperture and optical fiber light radiation angle can be increased, this is very effective for improving the coupling efficiency of described near-infrared LED light source and described lighting fiber, and makes fiber exit light angle increase, and expansion can illumination zone, therefore, the indoor optical fiber coupling LED auxiliary lighting system that the present invention proposes can meet the application demand of the field such as security protection, public security electronic monitoring floor light. It addition, this system fiber exit end area is less, having relatively strong disguised, range of application will be more extensive.

Various piece of the present invention can flexible configuration use, it is achieved the extension of system and performance boost. Such as, it can be the directional coupling method of example performed as described above selection between LED light source 2 and lighting fiber 4, and when LED light source 2 light-emitting area is less than lighting fiber 4 incidence end area, can also be coupled by coupling device 5, as shown in Figure 4, light angle of divergence after coupling device 5 that LED light source 2 sends is made more to meet lighting fiber aperture angle of incidence, increasing coupling efficiency further, available optical element has GRIN Lens, cylindrical lens, bitoric lens and increasingly complex lens combination etc.

For a person skilled in the art, it is possible to according to above technical scheme and design, make various corresponding change and deformation, and all these changes and deforms within the protection domain that should be construed as being included in the claims in the present invention.

Claims (10)

1. an indoor optical fiber coupling LED auxiliary lighting system, it is characterised in that include LED light source and lighting fiber; The incidence end of described lighting fiber and exit end are all tapered, and the light that described LED light source sends is coupled into lighting fiber from described incidence end and is transmitted and penetrates from exit end.

2. indoor optical fiber according to claim 1 coupling LED auxiliary lighting system, it is characterised in that also including fin, described LED light source is connected to one end of described fin.

3. the indoor optical fiber coupling LED auxiliary lighting system of one according to claim 1, it is characterised in that the incidence end of described lighting fiber and the diameter of exit end place covering and fibre core are all tapered along optical axis.

4. the indoor optical fiber coupling LED auxiliary lighting system of one according to claim 3, it is characterised in that in the whole cone district of incidence end and exit end, the diameter ratio of covering and fibre core keeps constant.

5. the indoor optical fiber coupling LED auxiliary lighting system of one according to claim 1, it is characterised in that also including optical fiber fixed port, the incident end face of described lighting fiber is arranged on against LED light source exit positions place by described light fixed port.

6. the indoor optical fiber coupling LED auxiliary lighting system of one according to claim 1, it is characterized in that, described LED light source is single near-infrared LED light source, and the near-infrared black light that described LED light source sends is coupled into lighting fiber from described incidence end and is transmitted and penetrates from exit end.

7. the indoor optical fiber coupling LED auxiliary lighting system of one according to claim 6, it is characterised in that the centre wavelength of described near-infrared LED light source is 940nm.

8. the indoor optical fiber coupling LED auxiliary lighting system of one according to claim 1, it is characterised in that when LED light source light-emitting area is less than lighting fiber incidence end area, described LED light source is coupled with lighting fiber incidence end by coupling device.

9. the manufacture method of the indoor optical fiber coupling LED auxiliary lighting system as described in above-mentioned any claim, it is characterised in that comprise the steps:

Lighting fiber incidence end and exit end, according to structural parameters set in advance, are carried out fused biconical taper process so that described incidence end and exit end are tapered by S1;

LED light source is installed on one end of described fin by S2, and is installed on the incidence end of described lighting fiber against LED light source exit positions place by described optical fiber fixed port.

10. manufacture method according to claim 1, it is characterised in that in step S1, the determination step of described structural parameters is as follows:

According to the ray theory accurate analysis light transmission characteristic at lighting fiber end, draw the relation of incidence end cone angle and incidence end aperture angle of incidence and exit end cone angle and exit end light radiation angle, determine one group of lighting fiber structural parameters making incidence end aperture angle of incidence and exit end light radiation angle try one's best big, wherein, described incidence end aperture angle of incidence represents that optical fiber accepts and transmits the ability of light, and on incident end face, incident angle all can enter spread fiber less than the light beam of this aperture angle of incidence;Described exit end light radiation angle represents can from the refraction angle corresponding to the light becoming maximum angle with optical fiber central axis of outgoing end face outgoing:

Take the incidence angle �� of light L1, a L1₀Being not provided with, equal to incidence end and the exit end when lighting fiber, the maximum aperture angle that tapering is correspondence, refraction angle is ��₀, L1 and lighting fiber side intersection point are the point of intersection of the side of the tapered end of the fibre core of lighting fiber and straight line portion side;

The incidence of lighting fiber end face same point and angle of incidence are less than ��₀Arbitrary light L2, be directly entered optical fiber normal propagation without incidence end offside reflection, and angle of incidence be more than ��₀Light, need to reflect through incidence end, if its angle of reflection is be more than or equal to lighting fiber critical angle, can propagate in lighting fiber; Take another light L3, angle of incidence be ��, L3 after incidence end offside reflection, its angle of reflection be equal to lighting fiber critical angle, therefore angle of incidence is more than ��₀And the arbitrary light less than or equal to �� all can meet propagation conditions after incidence end offside reflection, that is the angle of incidence arbitrary light less than or equal to �� can both enter described lighting fiber and in a fiber with less loss propagation, and �� is the aperture angle of incidence of described incidence end;

The cone length of described lighting fiber is h, and after lighting fiber fused biconical taper, the minimizing amount of fiber end face radius is y, and the incident tapered end diameter of lighting fiber is d, and when lighting fiber two ends are not provided with tapered, core diameter is l, then incidence end semi-cone angle �� is obtained by following formula:

$\left\{\begin{array}{c}\frac{y}{tan\mathrm{\α}}=\frac{y+d}{{\mathrm{tan\φ}}_0}=h\\ d+2y=l\end{array}\right.;$

Make the angle of reflection of light L3Equal to lighting fiber critical angle ��_c, ��_c=arcsin (n₂/n₁), utilize the law of refraction, obtain the incidence end aperture angle of incidence �� of described lighting fiber:

In formula, n₀Medium refraction index residing for lighting fiber, n₁For lighting fiber fiber core refractive index, n₂For lighting fiber cladding index;

The kind of the pattern can propagated in optical fiber and quantity can be described by lighting fiber normalized parameter R:

$R=\frac{2\mathrm{\π}r}{\mathrm{\λ}}\sqrt{n_1^2-n_2^2};$

In formula, r is lighting fiber fiber core radius, �� is wavelength, R value is more big, propagable pattern is more many, and namely in described lighting fiber, propagable pattern both depends on the R value of its small end, therefore, when the core diameter d of described lighting fiber incidence end is less than or equal to the core diameter of described lighting fiber exit end, can make to be coupled into light all effectively outgoing of described optical fiber;

Considering area mismatches loss when coupling, the incidence end core diameter d of described lighting fiber should try one's best greatly; Additionally, according to path reversal principal, when exit end cone angle is equal to incidence end cone angle, incidence the uniform light outgoing propagated in a fiber can be made, better illuminating effect can be reached, therefore the described incidence end of lighting fiber and the tapered end structural design of exit end are symmetrical structure, now, the light radiation angle of the exit end of described lighting fiber is equal to the aperture angle of incidence �� of incidence end.