Incoherent light illumination system based on optical fiber super lens

Abstract

The utility model discloses an incoherent light illumination system based on an optical fiber super lens. The system utilizes the characteristics of planarization, microminiaturization, high design freedom degree and the like of the super lens, effectively reduces the volume of a light source coupling part of the illumination system through the scheme of combining the super lens and the optical fiber, efficiently couples an incoherent illumination surface light source into the optical fiber, and converges and illuminates light emitted by the optical fiber to a specific small area by utilizing the super lens. And incoherent light illumination of a specific small area is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of super lens application, and specifically relates to an incoherent light illumination system based on an optical fiber super lens. Background Art

[0002] Fiber optic lighting refers to the transmission of light to any specific area through the anti-interference transmission of optical fiber. Due to the characteristics of optical fiber's flexible transmission, easy to bend but not easy to break, the direction of illumination can be easily changed. In addition, optical fiber has the advantages of light weight, anti-electromagnetic interference during light transmission, and miniaturization of the emission point. Therefore, the fiber optic lighting system has important application value in the fields of large-area indoor building lighting and small-area biomedical lighting.

[0003] However, fiber optic lighting systems still have problems such as large size and low light source coupling efficiency. Especially in the case of non-correlated surface light sources, it is difficult to couple large-angle light emitted by the surface light source into the optical fiber core, and larger geometric optical elements are often required to improve the coupling efficiency, making the light coupling part of the system relatively bulky. Utility Model Content

[0004] The purpose of the utility model is to provide an incoherent light illumination system based on an optical fiber superlens, which solves the problems of large volume and low light source coupling efficiency in the optical fiber illumination system.

[0005] The purpose of the utility model is achieved through the following technical solutions:

[0006] An incoherent light illumination system based on an optical fiber superlens comprises an illumination light source, a reflective cup, a first superlens, a filter, a second superlens, an optical fiber and a third superlens;

[0007] The surface light source emitted by the illumination light source is propagated in sequence in two ways: the order of small-angle light propagation is illumination light source, first super lens, filter, second super lens, optical fiber, third super lens, illumination area; the order of large-angle light propagation is illumination light source, reflective cup, filter, second super lens, optical fiber, third super lens, illumination area.

[0008] Furthermore, the reflective cup is used to collimate the large-angle light emitted by the light source; the first super lens is used to collimate the small-angle light emitted by the light source; the second super lens is used to converge the collimated light and couple it into the optical fiber; the third super lens is used to converge the light emitted by the optical fiber and irradiate it into the illumination area.

[0009] Furthermore, the illumination light source adopts an incoherent light source, including one of an LED light source, a xenon light source, an arc light source, and a quartz tungsten halogen light source; the illumination light source has a light emitting angle within a range of 40° to 180°; the illumination light source has an effective light emitting area diameter that is smaller than 2r of the opening diameter at the bottom of the reflector cup. min , and its position is close to the reflector, at the center of the opening groove at the bottom of the reflector.

[0010] Furthermore, the reflective cup includes a spherical reflection design and an aspherical reflection design, and the aspherical surface includes one of a hyperboloid, a parabola, an elliptical surface and a vertical elliptical surface; the bottom and top of the reflective cup are both open, and the bottom opening radius r min Ratio of top opening radius to max Small, light propagation direction is from bottom to top.

[0011] Furthermore, the radius of the first super lens r1 is less than or equal to the radius of the bottom opening of the reflective cup r min .

[0012] Furthermore, the focal length of the first superlens is f1=r1*z R / r max , where z R is the thickness of the reflective cup, r1 is the radius of the first superlens, r max is the opening radius of the top of the reflective cup; the first super lens has a position z1=f1 away from the illumination light source along the light propagation direction.

[0013] Furthermore, the radius of the second metalens, r2, is greater than or equal to the radius of the top opening of the reflective cup, r max .

[0014] Furthermore, the optical fiber is a multimode optical fiber, and the material includes plastic optical fiber or quartz optical fiber.

[0015] Furthermore, the radius of the third superlens is r3≥z3*tanθ f , where z3 is the distance between the third superlens and the optical fiber output end, θ f is the maximum acceptance angle of the optical fiber end face.

[0016] Furthermore, the third super lens has a focal length f3, a distance z3 between the third super lens and the optical fiber output end, and a distance z between the third super lens and the illumination area. s Satisfies Gauss's formula 1 / z3+1 / z s =1 / f3.

[0017] Beneficial effects of the utility model: This system addresses the difficulty of miniaturizing incoherent surface light sources and efficiently coupling them into optical fibers. By utilizing the planarization, miniaturization, and high degree of design freedom of the superlens, the system efficiently couples the surface light source into the optical fiber through two superlenses at the optical fiber coupling end, and converges the superlenses at the optical fiber coupling end to achieve small area light illumination. The utility model adopts a solution combining superlenses and optical fibers, and utilizes the advantage of the bendability of optical fibers to loosely couple the illumination optical path of traditional geometric optical elements. At the same time, the fine geometric features of the optical fiber and the ultra-thin geometric features of the superlens can further improve the space utilization rate in the optical machine, which helps to achieve incoherent light illumination with anti-interference transmission.

[0018] The aforementioned main scheme of the utility model and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection by the utility model; and in the utility model, (non-conflicting options) options and other options can also be freely combined. After understanding the scheme of the utility model, those skilled in the art can understand that there are many combinations based on the existing technology and common knowledge, all of which are technical schemes to be protected by the utility model, and they are not exhaustively listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of an incoherent light illumination system based on a fiber superlens according to an implementation example of the utility model.

[0020] Figure 2 This is a ray tracing diagram of an incoherent light illumination system of an implementation example of the utility model under illumination by a small-angle point light source.

[0021] Figure 3 This is a ray tracing diagram of an incoherent light illumination system of an implementation example of the utility model under illumination by a large-angle point light source.

[0022] Figure 4 This is a ray tracing diagram of an incoherent light illumination system of an implementation example of the utility model under illumination by a surface light source.

[0023] Figure 5 This is an irradiance diagram of the lighting area of ​​the incoherent light lighting system of the implementation case of the utility model under the illumination of a surface light source. DETAILED DESCRIPTION

[0024] The following non-limiting examples are used to illustrate the present invention.

[0025] Example 1

[0026] An incoherent light illumination system based on an optical fiber superlens comprises an illumination light source, a reflective cup, a first superlens, a filter, a second superlens, an optical fiber and a third superlens.

[0027] The surface light source emitted by the illumination light source in the system is propagated in sequence in two ways: the order of small-angle light propagation is illumination light source, first super lens, filter, second super lens, optical fiber, third super lens, illumination area; the order of large-angle light propagation is illumination light source, reflective cup, filter, second super lens, optical fiber, third super lens, illumination area.

[0028] The lighting source adopts an incoherent light source, including one of LED light source, xenon light source, arc light source, and quartz tungsten halogen light source. The lighting source has a light emitting angle within the range of 40° to 180°. The effective light emitting area of ​​the lighting source is smaller than the opening diameter of the bottom of the reflector cup by 2r min , and its position is close to the reflector, at the center of the opening groove at the bottom of the reflector.

[0029] The function of the reflector is to collimate the large-angle light emitted by the light source. The reflector includes a spherical reflection design and an aspherical reflection design. The aspherical surface includes a hyperbolic surface, a parabolic surface, an elliptical surface, and a vertical elliptical surface. The bottom and top of the reflector are both open, and the bottom opening radius r min Ratio of top opening radius to max Small, light propagation direction is from bottom to top.

[0030] The first super lens is used to collimate the small-angle light emitted by the light source. The radius of the first super lens r1 ≤ the radius of the bottom opening of the reflective cup r min The first super lens has a focal length of f1 = r1*z R / r max , where z R is the thickness of the reflective cup, r1 is the radius of the first superlens, r max is the radius of the top opening of the reflective cup. The first super lens is located at a distance z1=f1 from the illumination light source along the light propagation direction.

[0031] The second super lens is used to converge the collimated light and couple it into the optical fiber. The radius of the second super lens r2 ≥ the radius of the top opening of the reflective cup r max .

[0032] Optical fiber uses multimode optical fiber, and the materials include plastic optical fiber or quartz optical fiber.

[0033] The third super lens is used to converge the light emitted by the optical fiber and irradiate it into the illumination area. The radius of the third super lens is r3 ≥ z3*tanθ f , where z3 is the distance between the third superlens and the optical fiber output end, θ f The third super lens has a focal length of f3, a distance between the third super lens and the optical fiber output end, and a distance between the third super lens and the illumination area. sSatisfies Gauss's formula 1 / z3+1 / z s =1 / f3.

[0034] This system addresses the difficulty of miniaturizing incoherent surface light sources and efficiently coupling them into optical fibers. By utilizing the planarization, miniaturization, and high degree of design freedom of metalens, the system efficiently couples the surface light source into the optical fiber through two metalens at the fiber coupling end, and then converges the light through the metalens at the fiber decoupling end to achieve small area light illumination.

[0035] The system adopts a solution combining superlens and optical fiber, taking advantage of the bendability of optical fiber to loosely couple the illumination optical path of traditional geometric optical elements. At the same time, the fine geometric features of optical fiber and the ultra-thin geometric characteristics of superlens can further improve the space utilization rate in the optical machine and help realize incoherent light illumination with anti-interference transmission.

[0036] Implementation Cases

[0037] like Figure 1 As shown, this embodiment provides an incoherent light illumination system based on a fiber superlens, including an illumination light source, a reflective cup, a first superlens, a filter, a second superlens, an optical fiber, and a third superlens.

[0038] like Figure 1 As shown, in this example, an incoherent LED light source with a central wavelength of 470nm is selected when designing the optical path of the incoherent illumination system. The illumination light source is close to the bottom of the reflective cup, has an aperture of 1mm×1mm, and has radial radiation characteristics within an angle of -90° to 90°.

[0039] The first super lens in this example is placed in the reflective cup, mainly used to collimate the light with a smaller divergence angle. The radius is 2mm, the distance from the illumination light source is 2.1mm, and the focal length is also 2.1mm. Through simple geometric calculations, it can be obtained that the first super lens in this example can collimate the light with a divergence angle within 43.6°, such as Figure 2 As shown, this part of light cannot be reflected by the reflective cup due to its small divergence angle, so it is necessary to use a first super lens for collimation.

[0040] The reflective cup in this example adopts a parabola design, and its inner surface has a very high reflective property. It is mainly used to collimate the light with a larger divergence angle. The radius of curvature is 2, the radius of the bottom opening groove is 2mm, and the radius of the top opening groove is 5mm. The thickness of the reflective cup can be calculated to be 5.25mm by the parabola formula. Through simple geometric calculation, it can be obtained that the reflective cup in this example can collimate the light with a divergence angle greater than 43.6°, such as Figure 3 As shown, this part of light has a large divergence angle, and it is not easy to collimate it with a lens-type optical element, while the reflective cup can well collimate the light with a large divergence angle.

[0041] The filter in this example can be a narrow-band filter with a central wavelength of about 470 nm. The filter is about 0.75 mm away from the top of the reflective cup and has a thickness of 1 mm.

[0042] In this example, the second super lens is close to the filter, with a radius of 5 mm and a focal length of 7 mm. Light is converged by the second super lens and coupled into the multimode optical fiber.

[0043] The optical fiber in this example uses a single quartz-clad multimode optical fiber with a numerical aperture of about 0.22. The incident end is about 7.2 mm away from the second superlens. The coupled light is transmitted in the optical fiber with anti-interference and coupled out from the output end to form divergent light with a certain angle.

[0044] The third super lens of this example is about 3 mm away from the optical fiber output end, has a radius of 2.5 mm, and a focal length of 2 mm. It can collect the light emitted by the optical fiber and focus it into the illumination area.

[0045] In this example, the illumination area is selected as a small square area with a size of 2 mm×2 mm. The illumination area is about 6 mm away from the third superlens. Therefore, the distance between the third superlens and the optical fiber output end, the distance between the illumination area and the third superlens, and the focal length of the third superlens satisfy the Gaussian imaging formula.

[0046] Figure 2 The figure shows the ray tracing of the incoherent light illumination system in the embodiment of the utility model under the illumination of a small-angle point light source. It can be seen that when the emission angle of the point light source is relatively small (<43.6°), the light emitted by the point light source will not be reflected by the reflective cup, but will be collimated by the first superlens, and then converged and coupled into the optical fiber for transmission through the second superlens, and then irradiated into the illumination area through the third superlens.

[0047] Figure 3 The ray tracing of the incoherent light illumination system in an embodiment of the utility model under the illumination of a large-angle point light source is demonstrated. It can be seen that when the emission angle of the point light source is relatively small (>43.6°), the light emitted by the point light source will not pass through the first super lens, but will be reflected and collimated by the inner surface of the reflective cup, and then converged and coupled into the optical fiber for transmission through the second super lens, and then irradiated into the illumination area through the third super lens.

[0048] Figure 2 and Figure 3 It is a case of point light source illumination, but in actual conditions, the light source is a surface light source with a certain luminous area and a large divergence angle, that is, the LED surface light source selected as mentioned above. Figure 4The display shows the ray tracing results of the incoherent light illumination system implemented by the utility model under the illumination of a surface light source. It can be seen that the light emitted by the surface light source is relatively stray. Some of the light can be coupled into the optical fiber after being converged by the second super lens, while some of the light still cannot be coupled into the optical fiber. The light that cannot be coupled will no longer be transmitted backward. The light coupled into the optical fiber can basically be converged and illuminated to the illumination area after being emitted through the third super lens.

[0049] Figure 5 The irradiance diagram of the illumination area of ​​the incoherent light illumination system implemented by the utility model under the illumination of the surface light source is shown, and the illumination light is basically focused in the middle circular area. Through simulation calculation, it is found that the received light power efficiency of the illumination area can reach more than 32%, that is, more than one-third of the light energy of the surface light source can be used and illuminated in the illumination area, which is much higher than the efficiency of the traditional light path using geometric optical lenses (about 8%).

[0050] In general, this embodiment provides an incoherent light illumination system based on a fiber superlens, the illumination efficiency of which is higher than that of a traditional optical path design using a geometric optical lens. Meanwhile, compared with the optical elements of centimeters in size and thickness in the traditional optical path design, the optical elements of the fiber superlens design are thinner and smaller, the optical path is more compact, and the optical-mechanical space can be utilized more effectively.

[0051] The above basic examples and further optional examples of the utility model can be freely combined to form multiple embodiments, which are all embodiments that can be adopted and claimed for protection by the utility model. In the scheme of the utility model, each optional example can be arbitrarily combined with any other basic examples and optional examples.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An incoherent light illumination system based on a fiber superlens, characterized in that: It includes an illumination light source, a reflective cup, a first super lens, a filter, a second super lens, an optical fiber and a third super lens; The surface light source emitted by the illumination light source is propagated in two ways: the propagation order of small-angle light is illumination light source, first super lens, filter, second super lens, optical fiber, third super lens, illumination area; the propagation order of large-angle light is illumination light source, reflective cup, filter, second super lens, optical fiber, third super lens, illumination area; The illumination light source is at the center of the opening groove at the bottom of the reflective cup; the first super lens is placed in the reflective cup; the filter is located at the top of the reflective cup; the second super lens is close to the filter; the incident end of the optical fiber is coupled with the second super lens, and the emitting end of the optical fiber is coupled with the third super lens; The third super lens has a focal length f 3. The distance between the third super lens and the optical fiber output end z3. The distance between the third super lens and the illumination area z s Satisfies Gauss's formula 1 / z3+1 / z s =1 / f 3.

2. The incoherent light illumination system based on the optical fiber superlens according to claim 1, characterized in that: The reflective cup is used to collimate the large-angle light emitted by the light source; the first super lens is used to collimate the small-angle light emitted by the light source; the second super lens is used to converge the collimated light and couple it into the optical fiber; the third super lens is used to converge the light emitted by the optical fiber and irradiate it into the illumination area.

3. The incoherent light illumination system based on the optical fiber superlens according to claim 1, characterized in that: The illumination light source is an incoherent light source, including an LED light source, a xenon light source, an arc light source, or a quartz tungsten halogen light source; the illumination light source has a light emitting angle within a range of 40° to 180°; the illumination light source has an effective light emitting area whose diameter is less than 2r of the opening at the bottom of the reflector cup. min , and its position is close to the reflector, at the center of the opening groove at the bottom of the reflector.

4. The incoherent light illumination system based on a fiber superlens according to claim 1, characterized in that: The reflective cup includes a spherical reflective design and an aspherical reflective design, and the aspherical surface includes one of a hyperboloid, a parabola, an elliptical surface and a vertical elliptical surface; the bottom and the top of the reflective cup are both open, and the bottom opening radius r min Ratio of top opening radius to max Small, light propagation direction is from bottom to top.

5. The incoherent light illumination system based on optical fiber superlens according to claim 1, characterized in that: The radius of the first super lens r1 is less than the radius of the bottom opening of the reflective cup r min .

6. The incoherent light illumination system based on a fiber superlens according to claim 1 or 5, characterized in that: The first metalens has a focal length f 1=r1*z R / r max , where z R is the thickness of the reflective cup, r1 is the radius of the first superlens, r max is the radius of the top opening of the reflective cup; the first super lens is located at a distance z1 from the illumination light source along the light propagation direction= f 1.

7. The incoherent light illumination system based on a fiber superlens according to claim 1, characterized in that: The radius of the second super lens r2 is greater than or equal to the radius of the top opening of the reflective cup r max .

8. The incoherent light illumination system based on a fiber superlens according to claim 1, characterized in that: The optical fiber is a multimode optical fiber, and the material includes plastic optical fiber or quartz optical fiber.

9. The incoherent light illumination system based on a fiber superlens according to claim 1, characterized in that: The third super lens has a radius r3 ≥ z3*tan θ f , where z3 is the distance between the third superlens and the optical fiber output end, θ f is the maximum acceptance angle of the optical fiber end face.

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