White light fiber light source

Abstract

The utility model discloses a white light optical fiber light source, which is characterized in that a light source for remotely exciting fluorescence by laser is used as a unit light source coupled with an optical fiber; a multi-head beam combining optical fiber with one multi-head end and the other single-head end is used as an optical fiber coupled with a light source; the unit light sources are coupled with the optical fiber in the following mode that each end face of the multi-head end of the optical fiber is coupled with each unit light source, and light of each unit light source enters the optical fiber from the multi-head end of the optical fiber and is finally output from the single-head end of the optical fiber through the optical fiber. The utility model has the advantages of high brightness, high efficiency, high reliability, high flexibility and the like. The LED lamp can be applied to various application scenes such as machine vision, microscope observation, industrial detection, medical imaging, operation illumination and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of white light fiber light source, the utility model can be applied to machine vision, microscope observation, industrial detection, medical image, surgery illumination and a variety of application scenarios. BACKGROUND

[0002] Compared with traditional light source (such as incandescent lamp, fluorescent lamp), fiber-optic lighting light source has high efficiency, long life, beam concentration degree is high, directivity is good and the like advantages.High-brightness fiber-optic lighting light source has wide application in many fields, especially in the application scene needing high brightness, stable illumination and smaller volume, such as machine vision, microscope observation, industrial detection, medical image, surgery illumination and the like application scene.

[0003] The basic principle of fiber-optic lighting light source is that the light output by light source is transmitted to the area needing illumination by optical fiber.Optical fiber, as the medium of light transmission, can maintain high light efficiency while transmitting light in long distance.The brightness of light source and its coupling efficiency with optical fiber are two main technical difficulties of high-brightness fiber-optic lighting light source.

[0004] At present, common high-brightness fiber-optic light source adopts white light LED, laser diode (LD), xenon lamp and the like light source to couple with optical fiber.The brightness of xenon lamp is very high, but it has several great shortcomings, such as short life, large heat emission and large volume.Although white light LED has advantages such as long life and high light efficiency, its brightness (luminous flux output per unit emitting surface) is difficult to compare with that of xenon lamp, which leads to low coupling efficiency with optical fiber and limits its application in the application scene needing high brightness illumination. INVENTION CONTENTS

[0005] The utility model aims at solving the problem of insufficient brightness of current fiber-optic lighting light source, and proposes a new solution.

[0006] The utility model proposes a kind of high-brightness white light fiber light source, adopts laser remote excitation fluorescence light source as unit light source coupled with optical fiber;Adopt the multi-head of one end, the single head of the other end as the optical fiber coupled with light source of multi-head beam combination;Multiple unit light sources are coupled with optical fiber in the following mode: each end surface of the multi-head end of optical fiber is respectively coupled with each unit light source, and the light of each unit light source enters optical fiber from the multi-head end of optical fiber, and finally outputs from the single-head end of light intensity through optical fiber.

[0007] In one embodiment of the utility model, the structure of unit light source is as follows: monochromatic laser emitted from laser diode module is focused to the first surface of fluorescent film through multiple optical lenses, and converted into white light with longer wavelength after fluorescent film, and output from the second surface of fluorescent film;The first surface of fluorescent film is placed on transparent substrate, and the second surface is on the opposite surface of the first surface of fluorescent film.

[0008] In another embodiment of the utility model, the structure of unit light source is as follows: monochromatic laser emitted from laser diode module is incident on a dichroic lens at 45° after passing through multiple optical lenses, is focused to the second surface of fluorescent film after being reflected, and is converted into white light, re-enters the fluorescent film after being reflected by the first surface of the fluorescent film, and is output from the second surface of the fluorescent film; white light emitted from the second surface of the fluorescent film is output through the dichroic lens; the first surface of the fluorescent film is placed on the heat-conducting substrate, and the second surface is on the opposite surface of the first surface of the fluorescent film. The dichroic lens surface is coated with an optical film so that light with a wavelength of 440-470 nm is totally reflected, and light with a wavelength greater than 480 nm can pass through.

[0009] In another embodiment of the utility model, the structure of unit light source is as follows: monochromatic laser emitted from laser diode module is incident on a dichroic lens at 45° after passing through multiple optical lenses, is focused to the second surface of fluorescent film after being reflected, and is converted into white light, re-enters the fluorescent film after being reflected by the first surface of the fluorescent film, and is output from the second surface of the fluorescent film; on the opposite side of the laser diode module, a group of blue LED chips with an emission wavelength of 440-470 nm are arranged, and the blue light emitted by the blue LED chips is mixed with the light output from the second surface of the fluorescent film on the dichroic lens through the optical lens module. The first surface of the fluorescent film is placed on the heat-conducting substrate, and the second surface is on the opposite surface of the first surface of the fluorescent film.

[0010] In the above embodiment, the material of the fluorescent film can generate light with a longer wavelength under blue light excitation, and is one or a combination of the following materials: (Y, Tb)2Al5O 12 :Ce 3+ , (Sr, Ba, Ca)2Si5N8: Eu 2+ , CaAlSiN3: Eu 2+ , BaMgAl 10 O 17 : Eu 2+ , BaMgAl 10 O 17 : Eu 2+ , Mn 2+ , Ca-alpha-SiAlON: Eu 2+ , Beta-SiAlON: Eu 2+ , (Ca, Sr, Ba)2P2O7: Eu 2+ , (Ca, Sr, Ba)2P2O7: Eu 2+ , Mn 2+ , (Ca, Sr, Ba)5 (PO4) 3Cl: Eu 2+ , Lu2SiO5: Ce 3+ , (Ca, Sr, Ba)3SiO5: Eu2+ , (Ca,Sr,Ba)2SiO4:Eu 2+ , Zn2SiO4:Mn 2+ , BaAl 12 O 19 :Mn 2+ , BaMgAl 14 O 23 :Mn 2 + , SrAl 12 O 19 :Mn 2+ , CaAl 12 O 19 :Mn 2+ , YBO3:Tb 3+ , LuBO3:Tb 3+ , Y2O3:Eu 3+ , Y2SiO5:Eu 3+ , Y3Al5O 12 :Eu 3 + , YBO3:Eu 3+ , Y 0.65 Gd 0.35 BO3:Eu 3+ , GdBO3:Eu 3+ , YVO4:Eu 3+ .

[0011] The advantages of the utility model include following some aspects: (1) high brightness: multiple light sources are coupled into multiple input ends and finally concentrate to one output end, greatly improve the intensity of whole optical fiber output light; (2) high efficiency: smaller light source optical expansion quantity guarantees the coupling high efficiency of light source and optical fiber; (3) high reliability: the energy of single light source coupling optical fiber input end is relatively lower, reduces the energy (heat) loss of light source optical fiber coupling of optical fiber input end, improves the working environment of optical fiber; (4) high flexibility: multiple head input of input end, can adjust the number of light source according to the need. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is optical fiber coupling schematic diagram of light source.

[0013] Figure 2 It is multiple unit light source and optical fiber coupling schematic diagram.

[0014] Figure 3 It is implementation example 1 schematic diagram.

[0015] Figure 4 It is structure schematic diagram of fluorescent film used in implementation example 1.

[0016] Figure 5Schematic diagram for implementing example 2.

[0017] Figure 6 Schematic diagram for implementing example 2.

[0018] Figure 7 Schematic diagram for implementing example 3 DETAILED DESCRIPTION

[0019] The principle of a white light fiber optic light source can be described schematically as follows. Figure 1 As shown in the figure, light emitted from a light source (101) is converged by an optical lens (102) and enters the light entrance end face (103) of an optical fiber (104) at a certain angle, and is output from the other end (105) of the optical fiber (104). The ability of the optical fiber (104) to receive light is determined by its end face area (diameter) and its numerical aperture, i.e.: Figure 1

[0020] E1 = n1π 2 (d / 2) 2 (N.A.) 2 (1)

[0022] wherein E1 is the optical etendue of the optical fiber, n1 is the refractive index of the medium, d is the diameter of the end face of the optical fiber, and N.A. is the numerical aperture thereof.

[0023] On the other hand, the optical etendue E0 of the light source is determined by its light emitting area (diameter) and its divergence angle, i.e.:

[0024] E0 = n0π 2 (D / 2) 2 sin 2 θ (2)

[0026] wherein n1 is the refractive index of the medium, D is the diameter of the light emitting face of the light source, and θ is the half angle of the light emitting divergence of the light source.

[0027] This shows that only when the optical etendue E0 of the light source is smaller than the optical etendue (ability to receive light) E1 of the optical fiber, the light emitted from the light source can all enter the optical fiber; otherwise, the light emitted from the light source cannot all enter the optical fiber. In practice, the optical etendue of the light source is generally larger than the optical etendue of the optical fiber, and thus the maximum (coupling) efficiency η of the light source into the optical fiber can be approximately expressed as (considering the same medium, n1 = n0):

[0028]

[0029] ​As can be seen from expression (3), the coupling efficiency of the light source and the optical fiber depends on the area ratio of the light emitting surface of the light source and the receiving surface of the optical fiber, i.e. the square of the diameter ratio, and also on the divergence angle of the light source and the numerical aperture of the optical fiber.

[0030] Taking a light source exciting fluorescence by laser as an example, the light emitting half angle of the light source is generally 60°. Corresponding to different numerical apertures N.A. of the optical fiber, the maximum (coupling) efficiency of the light source into the optical fiber and the diameter ratio of the light emitting surface of the light source / the receiving surface of the optical fiber can be calculated according to expression (3) and listed in Table 1.

[0031] Table 1. Relationship between the maximum (coupling) efficiency of the light source into the optical fiber and the diameter ratio of the light emitting surface of the light source / the receiving surface of the optical fiber

[0032]

[0033] As can be seen from Table 1, the larger the diameter of the optical fiber relative to the diameter of the light emitting surface of the light source, or in other words, the smaller the light emitting surface of the light source relative to the receiving surface of the optical fiber, the higher the coupling efficiency of the light source into the optical fiber. For example, corresponding to an optical fiber with a numerical aperture of 0.56, the diameter of the light emitting surface needs to be as small as 2 / 3 of the receiving surface of the optical fiber so that the coupling efficiency of the light source into the optical fiber can reach 0.94; if corresponding to an optical fiber with a numerical aperture of 0.22, the maximum coupling efficiency of the above light source and optical fiber is only 15%.

[0034] For a given coupling efficiency of the light source and the optical fiber, the luminous flux into the optical fiber depends on the luminous flux of the light source. The total luminous flux generated by the light source is jointly determined by the area of the light emitting surface and the luminous flux per unit area, i.e. can be described by the following formula:

[0035]

[0036] wherein p is the luminous flux per unit area, or the luminous flux density of the light source

[0037] For a white light source based on the principle of laser exciting fluorescence, since a considerable amount of heat is generated on the light emitting surface in the process of converting laser into fluorescence, and the higher the total luminous flux of the light source, the more heat is generated, too much heat not only leads to a substantial reduction in the conversion efficiency of laser-white light, but also can cause the fluorescence film to fail directly. Therefore, it is very difficult for the light source to have both high luminous flux density and high luminous flux.

[0038] The present utility model proposes the following new solutions to achieve a substantial increase in the brightness of the optical fiber light source, i.e.:

[0039] (a) using multiple light sources with smaller light emitting surface diameter, lower relative luminous flux, but higher luminous flux density as unit light sources for coupling the optical fiber;

[0040] (b) using a multi-head input and single-head output multi-head coupling optical fiber as the optical fiber coupled with the light source; the total area of the input end face of the optical fiber is less than or equal to the area of the output end face of the optical fiber; the number of the multi-head end of the optical fiber is two or more, which is consistent with the number of the unit light source;

[0041] (c) coupling each input end of the optical fiber with a unit light source respectively, and the light generated from the multiple unit light sources enters the optical fiber from each input end and is output at the same output end through the optical fiber.

[0042] The above scheme is illustrated as Figure 2 As shown in Figure 2 , the diameter of each root end face of the input end optical fiber is d0, the diameter of the output end optical fiber is d1, and d0 and d1 maintain the following relationship:

[0043] (5)

[0044] If the light flux entering each optical fiber port of the input end is φ, then the total light flux entering the optical fiber is:

[0045]

[0046] Where Φ is the total light flux coupled into the optical fiber, and N is the number of input ends of the optical fiber.

[0047] Embodiment 1:

[0048] According to the above scheme, an embodiment of the utility model is illustrated as Figure 3 As shown in Figure 3 , three unit light sources A, B and C are coupled with the multi-head input end of the optical fiber. Taking a unit as an example, the monochromatic light (302) emitted by the laser module (301) is focused on the first surface of the fluorescent film (304) through the lens (303), and the lens (306) located above the second surface of the fluorescent film (304) focuses the white light (305) emitted from the fluorescent film (304) into light rays (307), which enter the multi-head end (308) of the optical fiber and reach the output end front end (310) through the optical fiber (309). The light emitted from the unit light sources B and C enters the multi-head end of the corresponding optical fiber according to the same setting, and is combined into a bundle of output (311) at the output end front end (310) of the optical fiber.

[0049] The light (302) emitted from the laser module (301) is monochromatic blue light with a wavelength of 440-470 nm, after entering the fluorescent film (304), part of the laser is absorbed and converted into light with a longer wavelength by the fluorescent film, and part of the unabsorbed laser continues to transmit through the fluorescent film by scattering. As shown in Figure 4As shown, to improve the heat dissipation performance of the fluorescent film, the fluorescent film is placed on a transparent, heat-conducting substrate (401) (usually sapphire). Furthermore, to ensure that the converted white light is completely transmitted toward the optical fiber, an optical film (402) is coated on the surface of the substrate (401) to allow all light with a wavelength of 440-470nm to pass through and all light with a wavelength greater than 470nm to reflect. The fluorescent film (403) is placed on the optical film (402).

[0050] Example 2:

[0051] Another embodiment of the present invention is shown in FIG. Figure 5 .like Figure 5 As shown, three unit light sources A, B, and C are coupled to the multi-head input end of the optical fiber. Taking the unit as an example, the monochromatic light (502) emitted by the laser module (501) first passes through the lens (503), then through the dichroic mirror (504) and lens (505) to focus on the fluorescent film (506). The lens (505) converges the white light (507) emitted from the fluorescent film (506) into parallel light, which passes through the dichroic mirror (504) and then through the lens (508) to form a light beam (509) that enters the multi-head end (510) of the optical fiber, passes through the optical fiber (511) and reaches the front end (512) of the output end. The light emitted by the unit light sources B and C enters the multi-head end of the corresponding optical fiber according to the same setting, and is combined into a beam output (513) at the front end (512) of the output port of the optical fiber.

[0052] The normal direction of the dichroic mirror (504) is 45 degrees to the normal direction of the lens (503) and the lens (505). The surface of the dichroic mirror is coated with an optical film so that light with a wavelength of 440-470nm is totally reflected and light with a wavelength greater than 480nm can pass through.

[0053] The light (502) emitted from the laser module (501) is a monochromatic blue light with a wavelength of 440-470nm. After entering the fluorescent film (506), part of the laser light is absorbed by the fluorescent film and converted into light with a longer wavelength. The part of the laser light that is not absorbed is scattered by the fluorescent film and continues to be transmitted through the fluorescent film. Figure 6 As shown, in order to improve the heat dissipation performance of the fluorescent film, the fluorescent film (603) is placed on a heat-conducting substrate (usually aluminum, copper or its alloy) (601). Furthermore, in order to ensure that the converted white light is completely transmitted in the direction of the optical fiber, an optical film is coated on the surface of the substrate (601) so that all light with a wavelength greater than 400nm can be reflected from the substrate and output from the exposed surface of the fluorescent film.

[0054] Example 3:

[0055] exist Figure 5In the illustrated embodiment, the light entering the optical fiber will not contain blue light with a wavelength between 440-470 nm due to the use of a dichroic mirror (504) in the optical path, and thus the color of the light will be yellowish. To solve the problem of the lack of blue light in the output light, a set of blue LED or laser diode chips (721) with an emission wavelength between 440-470 nm is added in the symmetric direction of the fluorescent film (716) in the illustrated embodiment. Figure 7 In another embodiment, a set of blue LED or laser diode chips (721) with an emission wavelength between 440-470 nm is added in the symmetric direction of the fluorescent film (716) in the illustrated embodiment. Figure 5 Based on the illustrated embodiment, a set of blue LED or laser diode chips (721) with an emission wavelength between 440-470 nm is added in the symmetric direction of the fluorescent film (716), and the monochromatic blue light (722) emitted by the chips passes through the lens (723) to the dichroic mirror (718). The light emitted from the fluorescent film (716) is mixed with the blue light (722) after passing through the dichroic mirror (718), and then converges through the lens (719) to enter the multi-end (730) of the optical fiber (731). The light emitted from the unit light sources B and C is divided into the multi-end of the corresponding optical fiber according to the same setting, and is combined into a bundle of output (733) at the front end (732) of the output port of the optical fiber.

[0056] The normal direction of the dichroic mirror (718) is 45° to the normals of the lens (713), the lens (715), and the lens (723), and the surface thereof is coated with an optical film such that light with a wavelength between 440-470 nm is totally reflected and light with a wavelength greater than 480 nm can pass through completely.

[0057] In the above-mentioned embodiments, the material of the fluorescent film can generate light with a longer wavelength under blue light excitation, and is one or a combination of the following materials: (Y, Tb)2Al5O 12 :Ce 3+ , (Sr, Ba, Ca)2Si5N8: Eu 2+ , CaAlSiN3: Eu 2+ , BaMgAl 10 O 17 : Eu 2+ , BaMgAl 10 O 17 : Eu 2+ , Mn 2+ , Ca-alpha-SiAlON: Eu 2+ , Beta-SiAlON: Eu 2+ , (Ca, Sr, Ba)2P2O7: Eu 2+ , (Ca, Sr, Ba)2P2O7: Eu 2+ , Mn 2+ , (Ca, Sr, Ba)5(PO4)3Cl: Eu 2+ , Lu2SiO5: Ce 3+ , (Ca, Sr, Ba)3SiO5: Eu 2+(Ca,Sr,Ba)2SiO4:Eu 2+ Zn2SiO4:Mn 2+ BaAl 12 O 19 :Mn 2+ BaMgAl 14 O 23 :Mn 2 + SrAl 12 O 19 :Mn 2+ CaAl 12 O 19 :Mn 2+ YBO3:Tb 3+ LuBO3:Tb 3+ Y2O3:Eu 3+ Y2SiO5:Eu 3+ Y3Al5O 12 :Eu 3 + YBO3:Eu 3+ Y 0.65 Gd 0.35 BO3:Eu 3+ GdBO3:Eu 3+ YVO4:Eu 3+ .

[0058] It must also be noted that the number of unit light sources in the above-described embodiments is three, and the number of multi-head input ends of the optical fiber is also three, but the present application does not limit the number of unit light sources and the number of input ends of the optical fiber. According to actual needs, the number of unit light sources and the number of input ends of the optical fiber can be two or more than two. Further, according to needs, the number of input ends of the optical fiber can also be more than the number of unit light sources. The output power of the output end of the optical fiber is the accumulation of the optical power of each unit entering the input end of the optical fiber.

[0059] It should be understood by those skilled in the art that the embodiments of the present application shown in the above description and the accompanying drawings are only examples and do not limit the present application. The purpose of the present application has been fully and effectively achieved. The function and structural principle of the present application have been shown and described in the embodiments, and the implementation of the present application can be any modification or change without departing from the principle.

Claims

1. A white fiber optic light source, characterized by, The unit light source is a laser remote excitation fluorescence light source; a multi-head coupling optical fiber is used as the optical fiber coupled with the light source; the unit light sources are coupled with the optical fiber in the following manner: each end face of the multi-head end of the optical fiber is coupled with each unit light source, and the light of each unit light source enters the optical fiber from the multi-head end of the optical fiber and is finally output from the single-head end of the optical fiber.

2. A white fiber optic light source as claimed in claim 1, wherein, One of the unit light sources is structured as follows: monochromatic laser emitted from a laser diode module is focused to the first surface of a fluorescent film through a plurality of optical lenses, is converted into white light with a longer wavelength after the fluorescent film, and is output from the second surface of the fluorescent film; The first surface of the fluorescent film is placed on a transparent substrate, and the second surface is on the opposite surface of the first surface of the fluorescent film.

3. The white fiber optic light source of claim 1, wherein, Another of the unit light sources is structured as follows: monochromatic laser emitted from a laser diode module is incident on a dichroic mirror at 45 degrees after passing through a plurality of optical lenses, is focused to the second surface of a fluorescent film after being reflected by the dichroic mirror, is converted into white light, is reflected by the first surface of the fluorescent film, re-enters the fluorescent film, and is output from the second surface of the fluorescent film; the white light emitted from the second surface of the fluorescent film is output through the dichroic mirror; The first surface of the fluorescent film is placed on a heat-conducting substrate, and the second surface is on the opposite surface of the first surface of the fluorescent film.

4. The white fiber optic light source of claim 1, wherein, Still another of the unit light sources is structured as follows: monochromatic laser emitted from a laser diode module is incident on a dichroic mirror at 45 degrees after passing through a plurality of optical lenses, is focused to the second surface of a fluorescent film after being reflected by the dichroic mirror, is converted into white light, is reflected by the first surface of the fluorescent film, re-enters the fluorescent film, and is output from the second surface of the fluorescent film; a group of blue LED chips with a wavelength of 440-470 nm are arranged opposite the laser diode module, the blue light emitted by the blue LED chips is mixed with the light output from the second surface of the fluorescent film on the dichroic mirror through an optical lens module; the first surface of the fluorescent film is placed on a heat-conducting substrate, and the second surface is on the opposite surface of the first surface of the fluorescent film.

5. A white fiber optic light source as claimed in claim 2, 3 or 4, wherein, The laser diode in the laser diode module has a wavelength of 440-470 nm, and there is one, two or more laser diodes.

6. A white fiber optic light source as claimed in claim 3 or 4, wherein, The dichroic mirror fully reflects light with a wavelength of 440-470 nm and fully transmits light with a wavelength of 470 nm or more.

7. The white fiber optic light source of claim 1, wherein, The number of the unit light sources is two or more.

8. The white fiber optic light source of claim 1, wherein, The number of the heads of the multi-head end of the optical fiber is two or more, and is consistent with the number of the unit light sources.

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