Light diffusing device for light immunotherapy
阅读说明：本技术 用于光免疫治疗的光漫射装置 (Light diffusing device for light immunotherapy ) 是由 安德烈亚斯·罗斯 凯尔·约翰斯顿 梅里尔·比尔 于 2018-04-24 设计创作，主要内容包括：本发明提供了一种漫射器光阻挡装置,其包括：端盖构件(820),该端盖构件具有带有侧壁(822)和端部反射表面(810)的袋状特征部(821)；袋状特征部的形状对应于具有远端端部表面(801)的漫射器(800)的远端部分(830)的外部形状；袋状特征部接合远端部分；袋状特征部的侧壁的交叠部分(815)围绕远端部分的侧壁(802),并防止从远端部分输出的光中的至少95％的光从远端部分的侧壁逸出；端部反射表面阻挡从远端端部表面输出的任何前向传播的光,并将来自远端端部表面的光中的至少80％的光朝向漫射器向回返；端盖构件是导热的；端盖构件的长度(831)和直径(832)提供外部表面积,该外部表面积至少为远端端部表面的表面积的1000％；并且该装置减少了漫射器辐照度热点的产生。(The present invention provides a diffuser light blocking device comprising: an end cap member (820) having a pocket feature (821) with a sidewall (822) and an end reflective surface (810); the shape of the pocket feature corresponds to the outer shape of a distal portion (830) of the diffuser (800) having a distal end surface (801); the pocket feature engages the distal portion; an overlapping portion (815) of the sidewalls of the pocket feature surrounds the sidewalls (802) of the distal portion and prevents at least 95% of the light output from the distal portion from escaping from the sidewalls of the distal portion; the end reflective surface blocks any forward propagating light output from the distal end surface and returns at least 80% of the light from the distal end surface back toward the diffuser; the end cap member is thermally conductive; the length (831) and diameter (832) of the end cap member provide an external surface area that is at least 1000% of the surface area of the distal end surface; and the arrangement reduces the creation of diffuser irradiance hot spots.)
1. A diffuser light blocking device comprising an end cap member having a length, a diameter, and a pocket feature, wherein:
a. the pocket feature comprises a sidewall and an end reflective surface;
b. the shape of the pocket feature corresponds to the outer shape of the distal portion of the diffuser;
c. the diffuser includes a distal end surface;
d. the pocket feature engages the distal portion;
e. an overlapping portion of the sidewalls of the pocket feature surrounds the sidewalls of the distal portion and prevents at least 95% of the light output from the distal portion from escaping from the sidewalls of the distal portion;
f. the end reflective surface blocks any forward propagating light output from the distal end surface and returns at least 80% of the light from the distal end surface back toward the diffuser;
g. the end cap member is thermally conductive to allow heat generated by absorption of light output from the distal end portion to be dispersed throughout the end cap member;
h. the length and the diameter of the end cap member provide an exterior surface area that is at least 1000% of the surface area of the distal end surface; and
i. the diffuser light blocking means reduces the creation of diffuser irradiance hot spots.
2. The device of claim 1, wherein a gap exists between the distal end surface and the end reflective surface.
3. The apparatus of claim 2, wherein the voids are filled with a compound that matches an index of refraction of a material of the diffuser.
4. The apparatus of claim 2, wherein the voids are filled with a titanium oxide filled epoxy.
5. The device of claim 2, wherein the voids are filled with a compound and the compound has a property selected from the group consisting of viscosity, light scattering, and combinations thereof.
6. The apparatus of any one of claims 1-5, wherein the overlapping portion of the sidewalls of the pocket feature prevents at least 98% of light output from the distal portion from escaping from the sidewalls of the distal portion.
7. The device of any one of claims 1 to 6, wherein the end cap member is made of aluminum.
8. The device of any one of claims 1 to 7, wherein the end cap member is biocompatible.
9. The device of any one of claims 1 to 8, wherein the end cap member comprises a sleeve and a stem, wherein: (i) the rod is inserted into the sleeve; (ii) the sleeve provides the sidewall of the pocket feature including the overlap portion, and the stem provides the end reflective surface of the pocket feature.
10. The device of any one of claims 1 to 9, wherein the end reflective surface returns at least 98% of light from the distal end surface back toward the diffuser.
11. The device of any one of claims 1 to 9, wherein the end cap member returns at least 80% of the light output from the distal end portion.
12. The device of any one of claims 1 to 9, wherein the end cap member returns at least 90% of the light output from the distal end portion.
13. The device of any one of claims 1 to 9, wherein the end cap member returns at least 98% of the light output from the distal end portion.
14. The device of any one of claims 1-13, wherein the exterior surface area of the end cap member is in a range from 1000% to 2000% of the surface area of the distal end surface.
15. The device of any one of claims 1-13, wherein the exterior surface area of the end cap member is in a range from 1500% to 2000% of the surface area of the distal end surface.
16. The device of any one of claims 1-13, wherein the exterior surface area of the end cap member is in a range from 1700% to 1900% of the surface area of the distal end surface.
17. A diffuser light blocking device comprising an end cap member having a length, a diameter, and a pocket feature, wherein:
a. the pocket feature comprises a sidewall and an end reflective surface;
b. the shape of the pocket feature corresponds to the outer shape of the distal portion of the diffuser;
c. the diffuser has a distal end surface;
d. the pocket feature engages the distal portion;
e. an overlapping portion of the sidewalls of the pocket feature surrounds the sidewalls of the distal portion and prevents at least 95% of the light output from the distal portion from escaping from the sidewalls of the distal portion;
f. the end reflective surface blocks any forward propagating light output from the distal end surface and returns at least 90% of the light from the distal end surface back toward the diffuser;
g. the end cap member is thermally conductive to allow heat generated by absorption of light output from the distal end portion to be dispersed throughout the end cap member;
h. the length and the diameter of the end cap member provide an external surface area from 1700% to 1900% of the surface area of the distal end surface;
i. the diffuser light blocking means reduces the creation of diffuser irradiance hot spots; and
j. a gap exists between the distal end surface and the end reflective surface.
18. A cylindrical light diffusing device, the cylindrical light diffusing device comprising: an optical fiber having a non-circular fiber core and a diffuser light blocking device, wherein:
a. the non-circular optical fiber core provides a "top hat" core irradiance distribution, and the cross-sectional shape of the non-circular optical fiber core in latitude is a regular polygon;
b. the light diffusing portion has a diffusing proximal end surface, a diffusing distal end surface, and internal scattering features distributed within the optical fiber core of the light diffusing portion along a central axis of the optical fiber core, wherein the light diffusing portion provides a "top hat" diffuse irradiance distribution, limiting variation in radially emitted irradiance from the light diffusing portion in the longitudinal direction to an average ("I0") within +/-15% of the optical irradiance;
c. the light diffusing portion further comprises a distal end portion, and the distal end portion comprises the diffusing distal end surface;
d. the diffuser light blocking means comprises an end cap member having a length, a diameter, and a pocket feature, wherein:
i) the pocket feature comprises a sidewall and an end reflective surface;
ii) the shape of the pocket feature corresponds to the outer shape of the distal portion of the light diffusing portion;
iii) the pocket feature engages the distal portion;
iv) an overlapping portion of the sidewalls of the pocket feature surrounds the sidewalls of the distal portion and prevents at least 95% of the light output from the distal portion from escaping from the sidewalls of the distal portion;
v) the end reflective surface blocks any forward propagating light output from the diffusive distal end surface and returns at least 80% of the light from the diffusive distal end surface back towards the diffusive portion;
vi) the end cap member is thermally conductive to allow heat generated by absorption of light output from the distal end portion to be dispersed throughout the end cap member;
vii) the length and the diameter of the end cap member provide an outer surface area that is at least 1000% of the surface area of the diffusive distal end surface; and
viii) the diffuser light blocking means reduces the creation of diffuser irradiance hot spots.
19. The apparatus of claim 18, wherein the regular polygon is a hexagon.
20. The apparatus of claim 18 or 19, wherein the light diffusing portion ranges from 10mm to 40 mm.
Technical Field
The present invention relates to a medical device for performing photo-immunotherapy (PIT), photodynamic therapy (PDT) or other light-activated therapy on a tissue, a cell or a cell-free organism of an organism and a method of using such a medical device in PIT, PDT or other light-activated therapy. More specifically, the present invention is a fiber optic diffusing device for delivering light to a treatment area in an illumination pattern and wavelength for PIT, PDT or other light therapy.
Background
PIT, PDT and other light-activated therapies have been used to treat a variety of ailments and diseases. PIT and PDT and other light-activated therapies typically involve the use of exogenous or endogenous photosensitizers or substances that are activated by electromagnetic radiation (e.g., light such as laser light, LED light). PIT is based on a new drug system consisting of cancer-targeting monoclonal antibodies conjugated with photoactivatable molecules. The targeting agent may include other moieties such as ligands, viral capsids, peptides, liposomes, nanoparticles, and the like. Such drug conjugates are not pharmacologically active until the conjugate binds to cancer cells and obtains anticancer activity at the tumor site via light-mediated activation. Tumor targeting and environmentally precise activation of drugs provide precise cancer specificity and allow rapid killing of cancer cells without damage to surrounding healthy tissue. The anti-cancer activity of PIT is very potent and it is applicable to many types of monoclonal antibodies and other targeting moieties, so this platform is able to target a wide range of cancer antigens and tumor types. It should be noted that the present invention is not limited to targeting tumor sites. Rather, the invention can also be used to target other cells and cell-free organisms, including bacteria, fungi, viruses, prions, and the like, to treat or prevent disease.
The essential requirement for PIT and/or PDT light sources being to match exogenous or endogenous photosensitizersThe activation spectrum (typically the wavelength of peak absorbance) and the generation of sufficient power at that wavelength can be ergonomically and efficiently delivered to the target tissue. Typically, up to several hundred mW cm-2At an irradiance of between 1 and 5W is required in the range of 630-850nm to provide treatment in tens of minutes. Furthermore, the light source must be reliable and cost-effective in a clinical environment.
For irradiating the area to be treated ("treatment area"), generally cylindrical diffusers and front (surface) diffusers, sometimes also referred to as "microlens diffusers", are used. Fiber cylindrical (side-emitting) and surface (front-emitting) diffusers consist of multimode fiber components, circular core/cladding structures with core diameters of 50-1000 μm, with a diffusing portion that can be directly connected to a light source, for example, by optical connectors.
I. Conventional cylindrical light diffuser
FIG. 1 shows an example of a generally commercially available cylindrical light diffusing device 100 that includes an optical connector 10 connected to a light source (not shown) at one end, an optical fiber 12, and a cylindrical diffuser 16 at the other end. During operation, the optical fibers 12 are in optical communication with the cylindrical diffuser 16, such that the cylindrical diffuser 16 couples out light with a longitudinally radially symmetric irradiance distribution 18 over a longitudinal length 19 of the cylindrical diffuser 16.
Fig. 2 shows a graph of irradiance at a vertical (i.e., latitudinal) section (shown as "11" in fig. 1) through the core of the optical fiber 12 taken before the optical fiber 12 enters the cylindrical diffuser 16. In this exemplary embodiment, the light source used is a 690nm laser with a 1 watt emission power, and the power is adjusted until the irradiance 18 measured at the center 17 of the longitudinal length of the diffuser 16 is 150mW/cm2. This measurement is made at 0.75mm from the central axis of the location of the diffuser 16. The optical fiber 12 leading from the light source to the cylindrical diffuser 16 ("guide fiber") was 2 meters long. The optical fiber 12 has a glass core with an Outer Diameter (OD) of 700 μm and a cladding with an OD of 740 μm. During operation, the optical fiber 12 is filled with laser light having a Numerical Aperture (NA) of 0.22 ") The angular distribution of (a). The cross-section 11 is obtained after 2 meters of guiding fiber (12). The associated irradiance distribution plots of fig. 2 from a longitudinal section through the center of the irradiance plot and a horizontal section show that the spatial uniformity of the irradiance distribution in the core of the optical fiber 12 ("core irradiance distribution") is poor. The larger value at the center of the graph indicates that the irradiance at the center of the fiber core is significantly higher than near its edges. The graph at the top of fig. 2 shows the irradiance distribution for a horizontal section, while the graph at the right of fig. 2 shows the irradiance distribution for a vertical section. As shown in fig. 2, both graphs have two axes: one axis represents width (e.g., diameter) in mm, and the other axis represents irradiance in watts/cm2。
Not only does the core irradiance distribution of optical fiber 12 have poor spatial uniformity, the longitudinally radially symmetric irradiance distribution coupled out along the outer surface of the irradiance-emitting portion of cylindrical diffuser 16 ("diffuse irradiance distribution") also exhibits poor spatial uniformity, resulting in an undesirable irradiance distribution as shown in FIG. 3. Such uneven irradiance distribution is undesirable because irradiance uniformity does not meet the need for proper "dosimetry," which represents the correct irradiance for optical power/surface area to achieve optimal therapeutic effect. In FIG. 3, the horizontal axis represents the longitudinal length (in mm) used to measure the length 19 of the cylindrical diffuser 16, while the vertical axis represents the watts/cm measured at 0.75mm from the central axis2Is the coupled-out irradiance at the surface of the cylindrical diffuser 16 in units.
FIG. 4 is an example of a generally commercially available cylindrical light diffusing device 200 that includes an optical connector 20 connected to a light source (not shown) at one end, an optical fiber 22, and a cylindrical diffuser 26 at the other end. During operation, the optical fiber 22 is in optical communication with the mode mixer 24 and the cylindrical diffuser 26, such that the cylindrical diffuser 26 couples out light with a longitudinally radially symmetric irradiance distribution 28 over a longitudinal length 29 of the cylindrical diffuser 26.
FIG. 5 shows the resulting through fiber 22 before fiber 22 enters cylindrical diffuser 26Graph of irradiance at a vertical cross-section of the core (shown as "21" in fig. 4). In this exemplary embodiment, the light source used is a 690nm laser with a 1 watt emission power, and the power is adjusted until the irradiance 28 measured at the center 27 of the longitudinal length of the diffuser 26 is 150mW/cm2. The measurement is made at 0.75mm from the central axis of said position of the diffuser 26. The optical fiber 22 leading from the light source to the cylindrical diffuser 26 ("guide fiber") is 2 meters long. The optical fiber 22 has a glass core with an OD of 700 μm and a cladding with an OD of 740 μm. During operation, the optical fiber 22 is filled with a laser having an angular distribution of numerical aperture ("NA") of 0.22. The cross-section 21 is obtained after 2 meters of guiding fiber (22). Unlike fig. 2, the associated irradiance distribution plot shown in fig. 5, taken from a vertical cross-section and a horizontal cross-section through the center of the irradiance plot, shows that when a mode mixer (24) is used with the optical fiber 22, a "top hat" irradiance distribution curve is obtained (i.e., the irradiance distribution varies less than +/-20% of the average irradiance across the cross-section), indicating a high degree of uniformity of the irradiance distribution in the core of the optical fiber 22 (e.g., an optimal core irradiance distribution). Similar to fig. 2, the graph at the top of fig. 5 shows the irradiance distribution for a horizontal section, while the graph at the right of fig. 5 shows the irradiance distribution for a vertical section. As shown in fig. 5, both graphs have two axes: one axis shows width (e.g., diameter) in mm and the other axis shows watts/cm2Is irradiance in units.
In contrast to the graph shown in fig. 3, the out-coupling longitudinal radially symmetric irradiance distribution (e.g., diffuse irradiance distribution) along the outer surface of the irradiance emitting portion of the cylindrical diffuser 26 shows spatial uniformity, which results in an optimal "top-hat" diffuse irradiance distribution, as shown in fig. 6. FIG. 6 shows that the variation in the out-coupled irradiance distribution should be a "top hat" which is less than the average of the cylindrical diffuser ("I") in terms of the radially emitted irradiance distribution0") +/-20% of the optical irradiance (e.g., optimal diffuse irradiance distribution). The horizontal axis of fig. 6 shows the longitudinal length in mm, while the horizontal arrowsThe length 29 of the cylindrical diffuser 26 is shown. The vertical axis of FIG. 6 shows the tiles/cm2Is the coupled-out irradiance at the surface of the cylindrical diffuser 26 measured in units of 0.75mm from the central axis.
As indicated above, to achieve the "top-hat" diffuse irradiance distribution of conventional cylindrical diffusers, optimal mode mixing (e.g., using an efficient mode mixer) in the fiber is required. The mode mixer 24 shown in fig. 4 is produced in the optical fiber 22 by a series of five successively alternating small radius bends. Another conventional mode-mixing method (not shown) is to tightly wind the optical fiber 22 around a target (e.g., a mandrel) multiple times. These popular forms of mode mixing produce spatial uniformity at the expense of increased transmission loss, typically resulting in losses of 50% or more. In addition, these techniques also create stress points within the optical fiber 22. Stressing an optical fiber is problematic because it can cause irreversible damage to such optical fiber because microbending pushes the fiber bending force to the maximum fatigue limit of the glass fiber. In addition, these cylindrical diffuser fiber assemblies can sometimes use optical powers in excess of 1 watt, which further reduces the maximum fatigue limit due to thermal heating from light lost from the fiber core. This thermal heating problem can adversely affect both glass and polymeric materials. In practice heat-destroyed mode mixers have emerged, which represents a major driving force to replace these conventional mode mixers with alternatives according to the described invention.
Note that an effective mode mixer by itself is not sufficient to obtain a "top-hat" diffuse irradiance distribution. An effective light diffuser or diffusing portion is also needed. For cylindrical diffusers, the diffuser portion typically uses additional elements and/or treatments to the diffuser portion to achieve a "top hat" diffuse irradiance distribution. As shown in fig. 7, one conventional method is to remove the cladding (diffusing portion) of the optical fiber tip 30 and etch the exposed optical fiber core with hydrofluoric acid or grind the optical fiber core on a polishing device. The resulting tapered tip with a frosted appearance is then covered with a protective transparent envelope 32. Referring to FIG. 8, another conventional approach is to fabricate a separate diffuser 34The diffuser comprises a scattering medium 36 made of micron-sized titanium oxide (TiO) embedded in a transparent epoxy or silicone elastomer2) Particles, the diffuser 34 being enclosed in a protective teflon sheath 38. The reflector 40, attached to the plastic plug 42, is then inserted into the open distal end of the sheath 38. The purpose of the coated plug 42 is to reflect any remaining forward propagating light back to the scattering medium 36 where it can be redistributed, thereby improving the uniformity of the emission curve. Another construction method can be described as a hybrid of the first two methods, where the cladding of the fiber is mechanically removed, roughening the surface of the core. This surface is then coated with a silicone elastomer onto which a second layer of elastomer impregnated with titanium oxide particles is deposited. Finally, as shown in FIG. 8, the entire diffusing tip is encapsulated in an outer PTFE tube, which in turn terminates in a reflective end cap in a manner similar to that described above. These described techniques are costly, labor intensive, and time consuming. Therefore, these light diffusers are very expensive.
It should be noted that other conventional techniques exist to provide a light diffuser that can produce a "top hat" diffuse irradiance distribution, such as having light scattering features (e.g., dimples, threads, cuts, general roughening, etc.) on the outside of the fiber surface. These techniques are labor intensive and the uniformity of the resulting light output pattern is heavily dependent on a constant fiber diameter, which can vary by as much as +/-5%, making it cumbersome to achieve constant and repeatable results during the manufacturing process. Furthermore, light scattering features on the smooth outer surface of the optical fiber often affect the mechanical strength of the optical fiber such that, for example, the tensile strength is significantly reduced.
Conventional front light diffusers
Referring to fig. 37A, an exemplary embodiment of a typical front (surface) diffuser 500 is provided with 690nm light that is introduced via fiber connector 503 onto an optical fiber 506 (e.g., a cylindrical optical fiber) having a 550 μm diameter core. 1/4-pitch, 1mm diameter graded index ("GRIN") lens component 504 is located at distal output face 510 of optical fiber 506, producing coupled-out light 502. Since the desired treatment region (i.e., target) 508 is much larger in diameter (e.g., 42mm) than the optical fiber 506 (e.g., 550 μm), the effect of lens component 504 on the first approximation is to form an image of the output face 510 of optical fiber 506 on target 508, where target 508 is located at some separation distance 512 (e.g., 64mm) away from lens component 504. In this way, the spatial irradiance distribution along the cross-section of the target 508 as shown in fig. 37C is closely related to the spatial irradiance distribution along the cross-section 510 as shown in fig. 37B. Note that this exemplary embodiment exhibits low loss (e.g., -0.25dB), where 1.0 watt of input power is sufficient to produce the irradiance distribution in fig. 37C. The fiber spatial irradiance distribution of the cylindrical optical fiber 506 at 510 is typically non-uniform, resulting in a non-uniform target spatial irradiance distribution at the target 508. This is undesirable for PIT and PDT applications that require a constant, uniform spatial irradiance distribution across the treatment area target 508.
Referring to fig. 38A, the general prior art solves the problem of non-uniform target spatial irradiance distribution at the target 508 as shown in fig. 37C by including a mode-mixing portion 520 in the optical fiber 506 at a predetermined distance in front of the lens component 504. The effect of the mode-mixing portion 520 is to convert the non-uniform cross-sectional spatial irradiance distribution at 510, as shown in fig. 38B, to a significantly more uniform cross-sectional spatial irradiance distribution at 514, as shown in fig. 38C. Thus, as shown in fig. 38D, the target spatial irradiance distribution produced by lens component 504 at target 508 will have a spatial irradiance distribution that is also more uniform.
The typical prior art mode-mixing section 520 not only produces a more uniform fiber spatial irradiance distribution, but also produces a more uniform angular intensity distribution at the output of the optical fiber 506. However, as shown in fig. 38A, when the target 508 is illuminated using the projection lens 504, the angular intensity distribution is less important than the spatial irradiance distribution. This is because the image formed by projection lens 504 maps substantially all light from one location in optical fiber 506 to a location on target 508, regardless of the angle of emission.
As described above, the mode mixing part 520 in the related art may be composed of: one or more small radius serpentine portions as shown in fig. 39A-39B, a coiled portion of a small radius ring as shown in fig. 39C, or a multi-wound portion with a small radius spiral as shown in fig. 39D. Other art-disclosed embodiments of mode mixing section 520 (e.g., alternating sections of graded and step index fibers, etc.) may also be used. However, all of these techniques suffer from significant drawbacks, in that they produce good mode mixing at the expense of high losses in the mode mixing portion 520. In one exemplary embodiment of the prior art, the configuration in fig. 38A is the same as that in fig. 37A, with the addition of a mode mixing portion 520 formed with a 7.5mm radius bend as shown in fig. 39A. This embodiment exhibits a loss of-2.32 dB, requiring 3.25 watts of input power to produce an irradiance distribution at the target, as shown in fig. 38D.
In the worst case, these losses mean that enough power leaks from the fiber 506 to heat the mode mixing portion 520, resulting in catastrophic failure of the diffuser 500 and even safety issues for the operator and patient. A more subtle drawback is that the losses incurred by these types of mode mixer portions 520 tend to vary from device to device, making it difficult to produce consistent products and calibrating the output from a pair of individual devices having different light sources.
Note that lens component 504 can include a combination of one or more of optical elements including spherical, aspherical, graded index, and diffractive elements. In the typical prior art, the optical fiber 506 and lens 504 are typically part of a disposable assembly and the lens component 504 tends to have a small diameter.
See 40A, which produces a divergence of the light beam 502 exiting the lens component 504. In general, the divergent nature of projection lens 504 results in different beam sizes at target locations 516, 508, and 518, located at separation distances 520, 512, and 522, respectively, in FIG. 40A. When the target moves from position 516, past 508, and ends at 518, the total power of the resulting beam is the same. However, as shown in the target spatial irradiance distribution in fig. 40B, the magnitude of the irradiance distribution at the target location becomes larger with distance, and the value of the irradiance decreases. This is not ideal because the intensity (power/area) of the irradiance of the beam decreases as the illuminated area increases as a function of distance from the output face of the lens component 504, resulting in only a narrow range of interval values where the irradiance meets the desired therapeutic value.
Drawings
The features and inventive aspects of the present invention will become more apparent upon reading the following detailed description, claims and drawings, of which the following is a brief description:
FIG. 1 is a graphical depiction of an exemplary cylindrical light diffusing device of the prior art;
FIG. 2 is a graph of irradiance at a vertical cross-section of an optical fiber of the cylindrical light diffusing device of FIG. 1 and its associated irradiance distribution plot;
FIG. 3 is a graph of longitudinally radially symmetric irradiance distribution out-coupled by the cylindrical light diffusing device of FIG. 1;
FIG. 4 is a graphical depiction of an exemplary cylindrical light diffusing device utilizing a mode mixer of the prior art;
FIG. 5 is a graph of irradiance at a vertical cross-section of an optical fiber of the cylindrical light diffusing device of FIG. 3 and its associated irradiance distribution plot;
FIG. 6 is a graph of longitudinally radially symmetric irradiance distribution out-coupled by the cylindrical light diffusing device of FIG. 3;
FIG. 7 is a graphical depiction of an exemplary cylindrical light diffuser of the prior art;
FIG. 8 is a graphical depiction of another exemplary cylindrical light diffuser of the prior art;
FIG. 9 is a graphical depiction of a cylindrical light diffusing device according to the present invention;
FIG. 10 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 11 is a graphical depiction of another embodiment of a cylindrical light diffusing device according to the present invention;
FIG. 12 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 13 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 14 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 15 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 16 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 17 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 18 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 19 is a vertical cross-sectional view of an exemplary embodiment of a non-round core optical fiber according to the present invention at the location of an internal scattering feature having a light diffusing portion;
FIG. 20 is a vertical cross-sectional view of an exemplary embodiment of a non-round core optical fiber according to the present invention at the location of an internal scattering feature having a light diffusing portion;
FIG. 21 is a vertical cross-sectional view of an exemplary embodiment of a non-round core optical fiber according to the present invention at the location of an internal scattering feature having a light diffusing portion;
FIG. 22 is a vertical cross-sectional view of an exemplary embodiment of a non-round core optical fiber according to the present invention at the location of an internal scattering feature having a light diffusing portion with another set of internal scattering features superimposed thereon.
FIG. 23 is a longitudinal cross-sectional view of a light diffusing portion of an exemplary embodiment of a non-round core optical fiber according to the present invention;
FIG. 24 is a longitudinal cross-sectional view of a light diffusing portion of an exemplary embodiment of a non-round core optical fiber according to the present invention;
FIG. 25 is a longitudinal cross-sectional view of a light diffusing portion of an exemplary embodiment of a non-round core optical fiber according to the present invention;
FIG. 26 is a longitudinal cross-sectional view of a light diffusing portion of an exemplary embodiment of a non-round core optical fiber according to the present invention;
FIG. 27 is a graph of irradiance at a vertical cross-section of the optical fibers of the cylindrical light diffusing device of FIGS. 9 and 14 and their associated irradiance distribution plots;
FIG. 28 is a graph of the out-coupled longitudinally radially symmetric irradiance distribution of the cylindrical light diffusing device of FIGS. 9, 10 and 14;
FIG. 29 is a vertical cross-sectional view of an exemplary embodiment of a square core optical fiber having projected paths for oblique and meridional rays;
FIG. 30 is a vertical cross-sectional view of an exemplary embodiment of a circular core optical fiber having projected paths for oblique and meridional rays;
FIG. 31 is a graphical depiction of an exemplary cylindrical light diffusing device according to the present invention;
FIG. 32 is an irradiance plot of a vertical cross-section of the optical fiber of the cylindrical light diffusing device of FIG. 31 and its associated irradiance distribution plot;
FIG. 33 is a vertical cross-sectional view of an exemplary embodiment of a round core optical fiber at a location having internal scattering features;
FIG. 34 is a graph of the out-coupled longitudinally radially symmetric irradiance distribution of the cylindrical light diffusing device of example II;
FIG. 35 is a graph of irradiance at a vertical cross-section of the optical fibers of the cylindrical light diffusing device of FIGS. 11 and 12 and their associated irradiance distribution plots;
FIG. 36 is a graph of the out-coupled longitudinally radially symmetric irradiance distribution of the cylindrical light diffusing device of FIGS. 11 and 12;
FIG. 37A is a graphical depiction of an exemplary front light diffusing device of the prior art;
FIG. 37B is a graph of spatial irradiance distribution along a vertical cross-section (510) of an optical fiber of the front light diffusing device of FIG. 37A;
FIG. 37C is a graph of the spatial irradiance distribution along a vertical cross-section (508) of the target for the front light diffusing device of FIG. 37A;
FIG. 38A is a graphical depiction of an exemplary front light diffusing device with mode mixing sections of the prior art;
FIG. 38B is a graph of spatial irradiance distribution along a vertical cross-section (510) of an optical fiber of the front light diffusing device of FIG. 38A;
FIG. 38C is a graph of spatial irradiance distribution along a vertical cross-section (514) of an optical fiber of the front light diffusing device of FIG. 38A;
FIG. 38D is a graph of the spatial irradiance distribution along a vertical cross-section (508) of the target for the front light diffusing device of FIG. 38A;
FIG. 39A is a graphical depiction of a prior art fiber mode mixing section with a small radius of one turn;
FIG. 39B is a graphical depiction of a prior art fiber mode mixing section with a small radius three turn;
FIG. 39C is a graphical depiction of a prior art fiber mode mixing section having three small radius rings formed about an axis perpendicular to the fiber axis;
FIG. 39D is a graphical depiction of a prior art fiber mode mixing section having two helical loops formed about an axis parallel to the fiber axis;
FIG. 40A is a graphical depiction of a prior art front light diffusing device showing a target treatment area at various separation distances (520, 512, 522);
FIG. 40B is a graph of the spatial irradiance distribution along a vertical cross-section (516, 508, 518) of the targeted treatment area for the front light diffusing device of FIG. 40A at various separation distances (520, 512, 522);
FIG. 41A is a graphical depiction of an exemplary embodiment of a front light diffusing device in accordance with the present invention;
FIG. 41B is a graph of spatial irradiance distribution along a vertical cross-section (608) of an optical fiber of the front light diffusing device of FIG. 41A;
FIG. 41C is a graph of spatial irradiance distribution along a vertical cross-section (610) of an optical fiber of the front light diffusing device of FIG. 41A;
FIG. 41D is a graph of spatial irradiance distribution along a vertical cross-section (614) of the target along the front light diffusing device of FIG. 41A;
FIG. 42A is a graphical depiction of another exemplary embodiment of a front light diffusing device in accordance with the present invention;
FIG. 42B is a graph of the spatial irradiance distribution along a vertical cross-section (718) of the front light diffusing device of FIG. 42A, and a graph of the spatial irradiance distribution along a vertical cross-section (720, 722) of the target treatment region at two separation distances (724, 726) of the front light diffusing device of FIG. 42A;
FIG. 43 is a vertical cross-sectional view of an exemplary embodiment of a non-circular core optical fiber according to the present invention at a location before the diffusing proximal end of the light diffusing portion;
FIG. 44 is a graphical depiction of a distal portion of a diffuser having uneven light emission caused by facets in the diffuser;
FIG. 45 is a graphical depiction of a distal portion of a diffuser having uneven light emission caused by facets in the diffuser;
FIG. 46 is a graphical depiction of a distal portion of a diffuser having non-uniform lighting due to backscattering during end processing of the diffuser;
FIG. 47 is a graphical depiction of the distal portion of the diffuser and the geometry of the rays that can escape the diffuser and produce a non-uniform light emission;
FIG. 48 is a longitudinal cross-sectional view of a distal portion surmounted by a diffuser light blocking device in accordance with one embodiment of the present invention;
FIG. 49 is a longitudinal cross-sectional view of the diffuser light blocking device shown in FIG. 48;
FIG. 50 is a longitudinal cross-sectional view of a distal portion of a diffuser tipped with another embodiment of a diffuser light blocking device according to the present invention; and
FIG. 51 is a longitudinal cross-sectional view of the diffuser light blocking device shown in FIG. 50.
Detailed Description
I. Providing a "top hat" core irradiance distribution without the light diffusing means of conventional mode mixers.
Referring to fig. 9-26, the present invention provides a light diffusing device 300 having a non-circular core optical fiber 302 that provides a "top-hat" core irradiance profile (i.e., an optimal core irradiance profile) without the use of a mode mixer (e.g., as shown at 24 in fig. 4). The light diffusing device 300 of the present invention delivers irradiance with a radially symmetric longitudinal "top hat" diffuse irradiance distribution (i.e., an optimal diffuse irradiance distribution) without the need to use the known light diffusers and/or diffusing portions described above.
Referring to fig. 9 and 11, the apparatus 300 further includes a drop fiber 304 and at least one optical connector 306. During operation, one end of the drop fiber 304 is in optical communication with a light source (not shown), while the other end of the drop fiber 304 is in optical communication with the proximal end of the non-round core fiber 302 through at least one optical connector 306, as shown in fig. 9 and 11. The non-circular core optical fiber 302 also includes a light diffusing portion 308 having a diffusing proximal end 310 and a diffusing distal end 312.
In the exemplary embodiment shown in fig. 9 and 11, the light diffusing portion 308 is located near the distal end of the non-circular core optical fiber 302. Further, the non-circular core fiber 302 may optionally include a light blocking means 314 (e.g., a solid cover, a coating such as an aluminum deposit, etc.) to prevent light emission from the surface or front face of the distal end of the non-circular core fiber 302. In one embodiment, the light blocking device 314 is a mirror that diverts and reuses light while avoiding over-illuminating the treatment area. This provides an efficient light diffusing means since only about 6% of the emitted light is coupled back into the drop fiber 304.
In one embodiment, the drop fiber 304 is connected to the light source through an additional optical connector 306. The drop fiber 304 may be any conventional fiber including, but not limited to, the fibers (12, 22) described above. At least one optical connector 306 connects the drop fiber 304 and allows the drop fiber to optically communicate with the non-round core fiber 302 during operation. An alternative to the at least one optical connector 306 is to introduce a conventional glue or fusion splice between the optical fiber 304 and the non-round core fiber 302. Moreover, in alternative exemplary embodiments, the non-round core fiber 302 also actually serves as a drop fiber 304 (creating a single fiber) and is connected to the light source by at least one optical connector 306, glue/fusion splice, or other conventional connection means. The at least one optical connector 306 may be any optical connector disclosed in the art (e.g., an SMA connector, etc.).
Fig. 13-18 show vertical (i.e., latitudinal) cross-sectional views of the non-circular core optical fiber 302 at 316, respectively, before the diffusive proximal end 310 of the light diffusive portion 308 (see fig. 9 and 11). Fig. 10, 12, and 19-22 show vertical cross-sectional views of the diffusing distal end 312 of the light diffusing portion 308 as shown in fig. 9 and 11, respectively. The non-circular core optical fiber 302 includes an optical fiber core 350. The non-circular core optical fiber 302 may optionally include a cladding 352 as shown in fig. 10, 12-14, and 16-18. The fiber optic core 350 has a non-circular geometry such as hexagonal (as shown in fig. 10 and 12-15), square (as shown in fig. 16-18), rectangular, triangular, octagonal, other regular and non-regular polygons. Thus, there are a variety of possible non-circular core shapes that can achieve uniform irradiance within the core. Some shape features make the shape particularly suitable for the present invention. While radial symmetry is not required, it does provide the benefits of ease of manufacture and facilitating a radially symmetric output irradiance pattern. The inflection points included in the cross-sectional curve where the tangent to the shape changes rapidly promote better mixing by sending adjacent light rays in different directions. The inclusion of facets also promotes better mixing by avoiding self-focusing behavior. Avoiding reentrant geometry facilitates manufacturing and avoids physically weak structures. The combination of these shape features tends to facilitate the use of regular polygonal shapes as the basis for non-circular core geometries. It should also be noted that a core having a helical or twisted shape may also be beneficial in producing spatially uniform irradiance in the core.
The cladding 352 may have the same non-circular vertical (i.e., latitudinal) cross-sectional geometry as the optical fiber core 350 (see, e.g., fig. 12, 13, and 16). Alternatively, the cladding 352 may have a circular outer surface geometry 354 having an inner surface geometry 356 that has the same general shape as the optical fiber core 350 (see, e.g., fig. 10, 14, 17, and 18).
Referring to fig. 15, 19-22, in some exemplary embodiments of the invention, the cladding 352 is not present, but is replaced by a closed open cavity or environment (e.g., air) 358 between the optical fiber core 350 and a covering 360 that is concentric with the optical fiber core 350 and radially encapsulates (but does not tightly encapsulate) the optical fiber core 350. The covering 360 can be any suitable art-disclosed polymeric material (e.g.,
As shown in fig. 12 and 18, the optical fiber core 350 and cladding 352 may be mixed and matched in different vertical cross-sectional geometries and combined with a closed open cavity 358 and/or a covering 360. For example and referring to fig. 18, a vertical cross-sectional view of a non-circular core optical fiber 302 shows its fiber core 350 having a square geometry. The inner surface geometry 356 of its cladding 352 matches this square geometry, while the outer surface geometry 354 of its cladding 352 is circular. The non-circular core optical fiber 302 also includes a closed open cavity 358 sandwiched between the cladding 352 and the covering 360. The cover 360 has a circular geometry.
In an exemplary embodiment of the apparatus 300 and referring to fig. 9 and 14, the fiber core 350 of the non-circular core fiber 302 is comprised of poly (methyl methacrylate) ("PMMA") having a hexagonal geometry in a circle circumscribing 660 μm in diameter. The optical fiber core 350 is clad with a cladding 352 having an inner surface geometry 356 having the same hexagonal geometry as the optical fiber core 350. However, the outer surface geometry 354 of the cladding 352 is circular. Cladding 352 is composed of silicone with an OD of 740 μm. The drop fiber 304 of the device 300 has a glass core with an OD of 200 μm and a cladding with an OD of 230 μm. The length of the non-circular core fiber 302 is 30 cm. During operation, core fiber 302 is filled with laser light having an angular distribution of 0.22 NA. It should be noted that other embodiments may include different materials for the core and cladding, including the use of various transparent or translucent glasses and polymers. If the total length of the diffuser is short, then the absorption rate is not of primary concern, but the material should not be opaque at the wavelengths of interest. For example, if a diffuser is used to provide UV illumination, a silica core lightguide is suitable, while the use of medium wave IR light will encourage the use of fluorite or silver halide glasses. A variety of injection moldable polymeric materials are suitable for use in visible and near infrared applications, including but not limited to PMMA, Polycarbonate (PC), and Polystyrene (PS). Various castable materials including epoxies and silicones are also advantageous. In all cases, care should be taken to ensure that the material is able to handle the required amount of optical power without adverse effects such as melting or cracking.
Fig. 27 shows a graph of irradiance of a vertical cross-section (shown as "316" in fig. 9) through the fiber core 350 taken just before diffusing the proximal end 310. The light source used was a 690nm laser with an emission power of 0.125 watts, and the power was adjusted until centered on the longitudinal length of light diffusing portion 308Irradiance measured at 307 was 150mW/cm2. Measured from 0.75mm from the central axis of the position of the light diffusion portion 308. The total length of the fiber leading from the light source to this location 316 (the combination of the drop fiber 304 and the non-circular core fiber 302) is 2 meters long. The associated irradiance distribution plot shown in fig. 27, taken from vertical and horizontal sections through the center of the irradiance plot, shows the same "top hat" core irradiance distribution as the conventional cylindrical light diffusing device 200 (shown in fig. 5) described above, which requires a mode mixer (24). This "top hat" core irradiance distribution indicates a high degree of uniformity of the irradiance distribution in the optical fiber core 350 (i.e., an optimal core irradiance distribution). In this specification, the "top hat" core irradiance distribution and/or the optimal core irradiance distribution shall be defined below as: all irradiance of the cross-section of the optical fiber core 350 is at least within +/-20% of the average irradiance of the cross-section of the optical fiber core 350, indicating a high degree of uniformity of the irradiance distribution in the core of the optical fiber 22. In some exemplary embodiments, the value of at least +/-20% may be further reduced to a +/-15% range, or even a +/-10% range.
Examining two types of light rays that may propagate in a perfectly symmetric cylindrical light guide may help understand how the non-circular core optical fiber 302 of the present invention provides a "top-hat" core irradiance distribution in the optical fiber core 350. The light may travel forward as "skew rays" that spiral around the outer edges of the fiber core 350 without passing through the central portion of the fiber core 350. This is depicted in fig. 30, which shows a vertical cross-sectional view of a round core fiber 301, where the projected path of the propagating oblique ray 366 always remains near the edge of the fiber core 351. It is also possible to have the meridional rays 368 have paths lying in a plane such that rays starting on the central axis of the light guide always pass through the central axis of the fiber core 351. By comparison and reference to FIG. 29, a vertical cross-sectional view of a square non-circular core fiber 302 having a similar projected path of propagating light rays is shown. The oblique ray 370 still propagates without passing through the central axis of the fiber core 350, but now its path is such that its energy can be found at some locations near the edge of the fiber core 350, while at other locations it can be found closer to the center of the fiber core 350. A meridional light ray 372 that begins on the central axis of the fiber core 350 may have a path that samples a substantial area of the fiber core 350 without passing through the axis again. These two examples illustrate how introducing a large set of rays at a range of different emission angles in a non-circular core fiber 302 produces a "top-hat" core irradiance distribution after a short propagation length (corresponding to only a few internal reflections).
Our studies indicate that any of the different embodiments described above of replacing the non-circular core optical fiber 302 shown in fig. 14 with a non-circular core optical fiber 302 will still allow the apparatus 300 to provide the desired "top hat" core irradiance distribution (e.g., fig. 13-18). For example, the fiber optic core 350 of FIG. 13 is the same as the fiber optic core 350 of FIG. 14. They are all made of PMMA, with hexagonal geometry in a circumscribed circle of 660 μm diameter. The non-circular core fiber 302 of fig. 13 differs from the core fiber of fig. 14 in that the cladding 352 of fig. 13 has a hexagonal geometry. The cladding 352 of FIG. 13 is composed of fluorinated polymer in a circumscribed circle of 740 μm diameter.
In another exemplary embodiment and referring to FIG. 15, the fiber optic core 350 has the same geometry and dimensions as the fiber optic core of FIG. 14, except that it is composed of polystyrene instead of PMMA. However, the non-circular core fiber 302 of FIG. 15 does not have a cladding 352. In contrast, the non-circular core fiber (302) also includes a closed open cavity 358 and a cover 360. The covering 360 is made of translucent
The exemplary embodiment shown in fig. 16 and 17 uses the same fiber core 350 composed of PMMA, which has a square geometry of 500 μm by 500 μm. The non-circular core fiber 302 of FIG. 16 has a cladding 352 composed of a fluorinated polymer with a square geometry of 540 μm by 540 μm. The non-circular core fiber 302 of fig. 17 has a different cladding 352 because it has a square inner surface geometry 356 and a circular outer surface geometry 354. Cladding 352 is composed of silicone having an outer diameter of 740 μm.
In another exemplary embodiment and referring to FIG. 18, the fiber optic core 350 has the same geometry and dimensions as the fiber optic core 350 of FIG. 17, except that it is composed of polystyrene instead of PMMA. Both having the same cladding 352. However, the non-circular core optical fiber 302 of FIG. 18 also includes a closed open cavity 358 and a cover 360. The covering 360 is made of translucent
In yet another exemplary embodiment and referring to fig. 12, the non-circular core optical fiber 302 is the core optical fiber shown in fig. 13 plus a combination of a closed open cavity 358 and a cover 360. The covering 360 is made of translucent
As described above, the non-circular core optical fiber 302 of the present invention, by virtue of its various shapes, materials, cladding (352), and covering (360), can provide a "top-hat" core irradiance distribution without the need for a mode mixer, thus providing a less expensive and more robust light diffusing device (300). The non-circular core optical fiber 302 of the present invention can be used in conjunction with one of the conventional illumination diffusers or diffusing portions described above to provide a "top hat" diffuse irradiance distribution.
Cylindrical light diffusing device providing a "top hat" diffuse irradiance distribution
In order for the apparatus 300 to provide a "top-hat" diffuse irradiance distribution without the use of such conventional light diffusers or diffusing portions, the apparatus 300 must include internal (i.e., not reaching the outer surface of the fiber core 350) scattering features 362, preferably laser written or written, within the light diffusing portion 308 as shown in fig. 9 and 11.
In this specificationWherein a "top-hat" diffuse irradiance distribution is defined as a longitudinal variation in coupled-out irradiance that is less than the average of a cylindrical diffuser for a radially emitted irradiance distribution ("I0") optical irradiance +/-20% (see, e.g., fig. 6), which indicates a high degree of uniformity. In some exemplary embodiments, the value of at least +/-20% may be further reduced to a +/-15% range, or even a +/-10% range.
The internal scattering features 362 generally begin at the diffusive proximal end 310 and end at the diffusive distal end 312. The internal scattering features 362 may be various shapes and patterns as shown in fig. 10, 12, 19-22, which illustrate vertical (i.e., latitudinal) cross-sectional views of the diffusive distal end 312 of the light diffusive portion 308. For example, the internal scattering features 362 may be (i) three cylinders oriented at 60 ° increments about the central axis of the fiber core 350, as shown in fig. 10, 12, 19; (ii) a single row of spheres concentric with the central axis of the fiber core 350, as shown in FIG. 20; (iii) a symmetric array of elliptical features (e.g., elliptical or spherical features) positioned at a radius about the central axis of the optical fiber core 350 in 60 ° increments as shown in fig. 21, and predetermined in a linear, non-linear, helical pattern, or pseudo-random pattern distributed along a predetermined longitudinal length of the optical fiber core 350; and (iv) a pair of parallel cylinders 361, wherein each of the pair of cylinders is located at a predetermined distance from the central axis of the optical fiber core 350, subsequent pairs of cylinders located at different longitudinal positions along the length of the light diffusing portion 308 are oriented at different angles about the central axis of the optical fiber core 350 (e.g., a pair of parallel cylinders 363 located at different cross-sections of the optical fiber and rotated 60 ° clockwise with respect to the pair 361). Note that while the embodiments discussed herein use 60 ° increments, other predetermined patterns may be suitable, such as, but not limited to, 45 °, 72 °, 90 °, 120 °, 180 ° increments. )
Each scattering feature 362 may be produced by a suitable laser as disclosed in the art. For example, focused, mode-locked 532nm10 picosecond laser pulses at 1.5 watts average power may produce the features 362 shown in FIG. 10, which consist of three cylinders, each cylinder having a diameter of about 27 μm and a length of about 270 μm, oriented in 60 increments about the central axis of the fiber core 350. In another example, a series of 520nm 400 femtosecond laser pulses of 2.0 watts average power focused through an objective lens having a numerical aperture of 0.4 may produce the features 362 (discussed in more detail below) shown in FIG. 43, each feature being a sphere of about 40 μm in diameter, centered at 60 ° increments around the central axis of the optical fiber core 350. Note that while the embodiments discussed herein use 60 increments, other degrees of increments are also applicable, such as 45 °, 72 °, 90 °, 120 °, 180 °, and so forth.
The scattering properties of each of the features 362 vary depending on the material, geometry, and process. As light scatters out of the non-circular core fiber 302, the proportion of light scattered per length or per feature 362 must increase as the optical density per length in the light diffusing portion 308 decreases. This may be accomplished by varying the number of features 362 per unit length or the size of the features 362 as a function of length. Depending on the amount of returned light that is acceptable, a linear increase in size may be sufficient, but a large non-linearity of size versus length may be preferred. In another exemplary embodiment, the number of features 362 per unit length may increase, while the size of the features 362 as a function of length may decrease. It should be noted that one skilled in the art may also vary the process parameters to vary the amount of scattering of each feature 362.
When the internal scattering features 362 are distributed in the light diffusing portion 308 along the central axis 364 of the non-circular fiber core 350 as shown in fig. 9 and 11, the light propagates along the light diffusing portion 308 and constant mixing occurs in the light diffusing portion 308 itself. When light in the center of the optical fiber core 350 encounters the internal scattering features 362 and is scattered out of the light-diffusing portion 308, the light redistribution ensures that the irradiance in the center of the optical fiber core 350 is replenished. This simplifies the challenge of finding a pattern of scattering features 362 to achieve a uniform emission pattern, while allowing the scattering features 362 to remain smaller and positioned towards the center of the light diffusing portion 308, resulting in a potentially physically stronger device with better emission characteristics.
Referring to fig. 23-26, the features 362 can also be longitudinally spaced in various patterns. For example, the features 362 may be longitudinally arranged in a uniform linear manner concentric with the central axis 364 of the fiber optic core 350, as shown in FIG. 23. By varying the number of features 362 per unit length, the features 362 can be arranged longitudinally in a non-uniform linear manner, as shown in fig. 24. In fig. 24, the number of features 362 per unit length increases from the diffusive proximal end 310 to the diffusive distal end 312 of the light diffusive portion 308. As described above and alternatively, the number of features 362 per unit length may decrease from the proximal diffuse end 310 to the distal diffuse end 312 of the light diffusing portion 308, but the size of the features 362 may increase from the proximal diffuse end 310 to the distal diffuse end 312 of the light diffusing portion 308.
Further, as shown in fig. 25, the features 362 may be arranged longitudinally in a uniform linear manner with linearly increasing dimensions. Finally, the features 362 may be arranged longitudinally in a uniform manner with non-linear increases in size, as shown in fig. 26.
Front light diffusing device providing "top hat" spatial irradiance distribution
Referring to FIG. 41A, the present invention provides a front light diffusing device 600 comprising an optical fiber connector 603, a cylindrical optical fiber portion 602, a non-circular core optical fiber portion 604, a fiber splicing member 605 joining the two optical fiber portions, and a lens member 606. During operation of apparatus 600, cylindrical fiber portion 602 is in optical communication with non-circular core fiber portion 604, and non-circular core fiber portion 604 is also in optical communication with lens component 606. The non-circular core fiber portion 604 may have the same characteristics as the non-circular core fiber 302 discussed above, providing a "top hat" core irradiance distribution (without the need to use a mode mixer), except that it does not include the optional light blocking means 314 discussed above. Note that the cross-section may also vary along the longitudinal length of the non-circular core fiber section 604 to help create better mixing, for example, there may be one or more regions of 604 where the outer dimension of the core increases and then decreases, or the core of 604 may have a varying amount of twist (i.e., rotation about the longitudinal axis of the fiber section 604) rather than straight crush, or the non-circular profile of 604 may change from one shape to another (e.g., hexagonal to square). The non-circular core fiber section 604 acts as a spatial mode mixer, causing several internal reflections of the propagating light, resulting in little or no loss of the propagating light.
As discussed below and in one exemplary embodiment, during operation, the cylindrical fiber portion 602 has a non-uniform fiber spatial irradiance distribution of light shown in fig. 41B measured at cross-section 608. The non-circular core fiber portion 604 outputs a significantly more uniform spatial irradiance distribution of the hybrid fiber measured at cross-section 610, as shown in fig. 41C. The target spatial irradiance distribution shown in fig. 41D produced by lens component 606 at target cross-section 614 is also more uniform. Thus, the hybrid spatial irradiance distribution measured at 610 and the target spatial irradiance distribution measured at 614 have a desired "top hat" spatial irradiance distribution. "Top-hat" spatial irradiance distribution and/or optimal spatial irradiance distribution, as will be defined hereinafter, is a distribution in which the variation of the out-coupling spatial irradiance distribution with respect to irradiance distribution is less than the average of the front diffuser ("I0") optical irradiance, which indicates a high degree of uniformity of the spatial irradiance distribution at the relevant location (e.g., at 610 and/or at target 614). In some exemplary embodiments, the value of at least +/-20% may be further reduced to a range of +/-15%, or even a range of +/-10%.
In the prior art, the mixing of propagation angles means that some rays of light that do propagate along the core of the fiber are perturbed to angles that exceed the critical angle of the fiber and are emitted, resulting in transmission losses and other undesirable effects, such as local heating of surrounding materials. The non-circular core fiber sections 604 do not change angle so that they cannot propagate, they merely rearrange the path of the light rays while maintaining the angle of each light ray relative to the optical axis of the non-circular core fiber sections 604. As noted above, variations in the shape or size of the non-circular core fiber portion 604 may be produced along the length of the mixing section such that a controlled amount of angular mixing may be included in the effect of the non-circular core fiber portion 604, noting that any increased angular mixing will also be accompanied by the introduction of corresponding transmission losses.
In an alternative embodiment of the present invention, non-circular core fiber section 604 may extend from the light source to the projection lens (e.g., 606), or as shown in FIG. 41A, a short section 604 may be used after cylindrical fiber section 602 and before lens section 606. Note that if a portion of the cylindrical optical fiber 602 is used between the non-circular core fiber portion 604 and the lens component 606, it should be noted that the portion of the cylindrical optical fiber 602 is not too long (e.g., less than 0.25 meters, etc.) or that the mixed spatial irradiance distribution measured before 606 may again become non-uniform.
As discussed above for the non-circular core fiber 302, the non-circular core fiber portion 604 may be a single piece of material that is joined using a standard fiber optic connector 605, or may be melted into place by gluing or even by fusion bonding techniques (e.g., soldering, etc.) to be permanently secured to one end of the cylindrical fiber portion 602. The non-cylindrical portion 604 may also be molded or stamped into an otherwise cylindrical portion of the optical fiber 602. It should be noted that the connection between the cylindrical fiber section 602 and the non-circular core fiber section 604 is designed to minimize losses, e.g., matching dimensions and maximum propagation angles.
Referring to FIG. 41A and in one exemplary embodiment of an apparatus 600, a cylindrical fiber portion 602 includes a core fiber composed of glass having a core with an OD of 600 μm covered by a cladding with an OD of 630 μm. Its Numerical Aperture (NA) is between 0.22 and 0.26. The non-circular fiber core portion 604 is at least 50mm in length and is composed of glass, has a hexagonal geometry with an ID of 600 μm, and has a cladding with an OD of 680 μm. Lens component 606 comprises an 1/4 pitch, 1mm diameter GRIN lens.
In one exemplary embodiment, the light source used is a 690nm laser with a 2.4 watt emission power, and the power is adjusted until the irradiance measured at the target 614 is 150mW/cm2With a top hat profile having a 42mm inner diameter when measured using a separation distance (e.g., 616) of 64 mm. This embodiment exhibits a low transmission loss of-0.36 dB. Optical fiber (cylinder) from light source to projection lens 606The combination of the shaped fiber section 602 and the non-circular core fiber section 604) has a total length of 2 meters.
During operation, the cylindrical fiber portion 602 has a non-uniform fiber spatial irradiance distribution of light shown in fig. 41B measured at cross-section 608. The non-circular core fiber portion 604 outputs a significantly more uniform spatial irradiance distribution of the hybrid fiber as shown in fig. 41C, measured at cross-section 610. The target spatial irradiance distribution as shown in fig. 41D produced by lens component 606 at target cross-section 614 is also more uniform. Thus, both the hybrid spatial irradiance distribution measured at 610 and the target spatial irradiance distribution measured at 614 have the desired "top hat" spatial irradiance distribution.
As shown in fig. 40A and 40B, the related art front illuminator has a divergent light beam. This forces the operator to maintain the illuminator at a very specific interval from the target area during treatment in order to achieve the desired irradiance level. An ideal front illuminator would have the same irradiance on the target regardless of the separation distance. In addition, the ideal front illuminator also allows for easy adjustment of the size and shape of the illumination pattern on the target.
Referring to FIG. 42A, the present invention provides a front light diffusing device 700 that meets these objectives, including an optical fiber 702 having a proximal connector 703, a distal terminal 705, and a collimating lens assembly 704. The optical fiber 702 may be a cylindrical optical fiber, a non-circular core optical fiber (e.g., 302, 604), or a combination thereof, as discussed above. The collimating lens assembly 704 includes a collimating lens 706, which may be composed of a transparent optical material, i.e., glass, crystal, transparent polymer, or reflective material. The collimating lens 706 can include a single optical element or a combination of optical elements. The collimating lens 706 may have any combination of spherical, aspherical, refractive, diffractive, or reflective surfaces, and the material may have a graded index profile. Allowing the natural diverging light output 708 of the optical fiber 702 to expand to encounter the collimating lens 706. The optical fiber 702 is positioned such that its output face 710 is approximately at the back focal length 712 of the collimating lens 706. An iris 714 is located at or near the output of the collimating lens 704 where it can block a portion of the light output 708, producing a light output beam 716, the extent of which corresponds to the opening in 714. As shown in fig. 42A, only a central portion of the light output 708 from the optical fiber 702 is allowed to pass through the aperture 714 (i.e., collimated light output 716). This results in a collimated light output 716 having a "top hat" irradiance distribution, as shown in fig. 42B, that has substantially the same magnitude (e.g., less than +/-20% difference in values, less than +/-15% difference in values, or even +/-10% difference in values) at: (i) the near field (e.g., cross-section 720 at separation distance 724), (ii) the far field (e.g., cross-section 722 at separation distance 726), and the distance between the near and far fields, hereinafter defined as a "flat irradiance distribution".
The expanded cone of light from the fiber 702 is intentionally allowed to escape the collimating lens 706. The solid line in the graph in fig. 42B is the irradiance distribution measured at the location 718 shown in fig. 42A. The portion with the highly varying distribution is allowed to fall on the structure of the collimating lens 704 and be blocked, reflected or absorbed. Only the uniform central portion of the irradiance distribution passes through both the collimating lens 706 and the iris 714 to produce the output beam 716, producing a flat irradiance distribution 720, as shown by the dashed line in fig. 42B.
An aperture 714 located on the output side of the collimating lens 704 blocks undesired portions of the light output 708. In a preferred embodiment, the aperture 714 is an iris aperture, which allows the diameter of the beam size to be varied from 1mm to 12 mm. Alternatively, the aperture 714 may be configured to produce a square, rectangular, or even asymmetric light output.
The collimated light output 716 after the aperture 714 has very low divergence such that the size of the light output 718 in the near field (at position 720 in fig. 42A) is approximately the same as its size in the far field (at position 722 in fig. 42A). Referring to fig. 42B, the flat irradiance distribution produced at section 720 (shown as a dashed line) and section 722 (shown as a dashed line) is very close to the flat top irradiance distribution, and the beam size does not change significantly with distance (hereinafter defined as "flat irradiance distribution").
In one exemplary embodiment of the front light diffusing device 700, the core of the input optical fiber400 μm in diameter and 430 μm in cladding diameter, and filled with 1.01 watts of 690nm light, which has a numerical aperture of 0.29. The collimator lens 706 is composed of a plano-convex lens having a diameter of 25mm and a focal length of 75 mm. In this embodiment, when 150mW/cm is produced at 7202Less than 0.85 watts of excess optical power absorbed by the handpiece for a 12mm diameter beam, which is easily dissipated by the body of the handpiece. Referring to fig. 41A-42B, the flat irradiance distribution at section 720 was measured at a separation distance 724 from the aperture 714100mm, and the flat irradiance distribution at section 722 was measured at a separation distance 726 from the aperture 714200 mm.
The performance of this embodiment 700 exhibits several advantageous characteristics. First, the size and geometry of the light output can be adjusted over a wide range without changing the irradiance (milliwatts/cm) at the target2). Second, the irradiance produced on the target has little dependence on the separation distance between the projector and the target. These features make it easy to calibrate the output of the light source to produce the desired level of therapeutic light and make it easier for the operator to position the illuminator to achieve the desired exposure level. Note that the light output of the unmodified cylindrical optical fiber 702 is used in fig. 42A. A wider output beam can be obtained if the use of an angular mode mixing section or a non-circular core fiber section (e.g., 302, 606) produces a more uniform, flat-topped angular distribution than 718 in fig. 42B. In addition, non-circular core input fibers may be used.
Diffuser light blocking device
When using a diffuser in PIT/PDT applications, it is important that the diffuser does not generate any thermal state of the surrounding tissue above 42 ℃, which can cause cell damage to the surrounding tissue and reduce the effectiveness of the treatment. For example, if 100mW of forward propagating light remains at the distal end of a diffuser having a 500 μm diameter core, the transmitted irradiance at the distal-most surface may be 50Watts/cm2This is more than sufficient to cause thermal damage to surrounding tissue. If a light blocking means is used at the distal end of the diffuser to reduce the transmitted light, it is important that it does not absorb enough light energy to undergo a thermal rise and cause a diffuse light riseThe surface temperature of the emitter exceeds 42 ℃.
It is also important that the diffuser not be able to generate or produce (hereinafter collectively "produce") any "irradiance hotspot," which is a localized area of light output above a specified therapeutic level (hereinafter defined as "diffuser irradiance hotspot(s)"). For example, when a treatment regimen specifies 150mW/cm2Local irradiance exceeding this level by 20% can prematurely bleach the PIT/PDT compounds in the local area, deactivating them before treatment is complete and thereby reducing their overall effectiveness.
At the distal end of the diffuser is a feature that can interact with light propagating through the diffuser to create diffuser irradiance hot spots. Referring to the distal end 851 of diffuser 850 shown in fig. 44, facets 852 are shown on the distal surface 853 of diffuser 850, similar to chips, bevels, or other deviations from a perfect vertical plane that may be inadvertently created during typical manufacturing processes due to manufacturing variations. The mirror 854 is shown applied as a light blocking means to the distal surface 853. Facet 852 is also mirrored, as mirror 854 is applied after distal end 851 is created. Light rays 856 that interact with facets 852 do not return directly into diffuser 850, but instead are reflected upward from sides 855 of diffuser 850 as local non-uniform irradiance output 858. This reflected irradiance is not isotropically scattered as is the rest of diffuser 850, but is somewhat directional, producing localized regions of non-uniform irradiance output. For example, if 100mW of forward propagating light remains at the distal end 851 of diffuser 850, then facet 852 represents 5% of the cross-sectional area of diffuser 850, 80% of incident light incident on facet 852 is reflected off mirrored surface 857, and power extracted through side 855 radiates 1mm near the surface of diffuser 8502Area, then the local irradiance produced by facet 852 may be 400mW/cm2. This irradiance may also combine with the irradiance output from the remainder of diffuser 850, producing an unacceptable diffuser irradiance hotspot condition.
FIG. 45 shows a similar diffuser 860 with undesired facets 862Distal end 861, where a separate scope component 864 is provided as a light blocking means. Some of the forward propagating light 868 in diffuser 860 will be transmitted through facet 862, bypass mirror 864, and terminate as locally non-uniform output 869. Some of the forward propagating light 866 will undergo total internal reflection from facet 862 and eventually be directed out of side 863 of diffuser 860, producing different areas of locally non-uniform irradiance output 867. Some of this light will interact with facet 862 but is appropriately directed by mirror 864 and returned into core 865 of diffuser 860. For example, if 100mW of forward propagating light remains at the distal end 861 of diffuser 860, then facet 862 represents 5% of the cross-sectional area of diffuser 860, and 30% of the incident light on facet 862 is transmitted from side 863 to 1mm230% are totally internally reflected into 1mm from the side 8632And the remaining portions are properly reflected and recaptured, then the local irradiance from both the transmitted and reflected beams may be 150mW/cm2. If these local irradiances were combined with light from the rest of the diffuser 860, multiple unacceptable diffuser irradiance hot spot states could result due to the same manufacturing defects.
Fig. 46 shows a distal end 871 of a further diffuser 870, in which a scattering compound 872 is provided as light blocking means. The forward propagating light 874 will scatter back from 872, wherein some of the back scattered light will escape as light rays 876 from the side 873 of the diffuser 870. While light scattered from the body of diffuser 870 may be isotopically scattered as 4p steradians, all light energy scattered from 872 would become 2p steradians. This means that the light rays 876 may produce a local irradiance that is twice the irradiance produced by the body of the diffuser 870, thereby creating an unacceptable diffuser irradiance hotspot. This is an example of a design choice that may lead to unexpected performance problems.
Another potential root cause of uneven irradiance output may be related to the uniformity of the end treatment. For example, if the distal end of the diffuser has a reflector formed from a metal deposit, but the reflector has voids, an uneven emission pattern may result. This is another example of manufacturing variation that may lead to unexpected performance issues. The combination of design issues and manufacturing variations may result in diffuser irradiance hot spots observed near the distal end of the diffuser exceeding the treatment specifications and reducing the treatment efficacy. The process of addressing or screening these manufacturing variances may result in increased manufacturing complexity, reduced component yield, and increased production costs.
Accordingly, it is desirable to provide an end treatment for a diffuser that can simultaneously block transmitted light, block the creation of diffuser irradiance hot spots, and avoid creating unacceptable thermal conditions in the surrounding tissue. Ideally, the solution should also help to protect the ends of the diffuser and not be complex or expensive to manufacture or install. It would be particularly beneficial if the solution could correct minor manufacturing variations and certain design problems, thereby simplifying the manufacturing process, increasing yield and reducing cost.
To block light from the distal end of the diffuser that can create diffuser irradiance hot spots, it is useful to understand the physical principles of frustrated total internal reflection of the predominantly back-propagating light as depicted in FIG. 47. Fig. 47 shows the distal end 881 of the diffuser 880. For diffusers made of materials with refractive indices greater than 1.42, Snell's law states that light rays 886 internally incident on the interior of the diffuser 880 at angles θ greater than 45 from normal will be Totally Internally Reflected (TIR) and contained within the diffuser 880. Light rays 885 below this critical angle can escape from the sides 883 of the diffuser 880 and help create diffuser irradiance hot spots. Thus, the end treatment of the diffuser 880 that can block, absorb, reflect, or backscatter light rays 885 can significantly reduce the creation of diffuser irradiance hot spots. The incident light ray 884 shows the worst case light ray that needs to be contained, which is scattered or otherwise redirected from the extreme angles of the diffuser 880 into a light ray 886. Assuming a 45 angle to the lower corner of the diffuser 880 having a diameter as shown at 888, a blocking area 889 having the same size as the diameter 888 will be sufficient to block light rays from escaping light rays 885. Therefore, an end treatment having a blocking size of at least the diameter of the diffuser 880 is required.
If the light blocking means comprises perfect mirrors, all incident light will be diverted and the light blocking means will not absorb light energy and convert it into heat. Therefore, end treatment of highly reflective back reflectors with low absorption is desirable. Furthermore, if the light barriers are to absorb light energy but have a very small surface area, the thermal energy per surface area may be high, resulting in an unacceptable temperature rise. For example, if 100mW of light energy is incident on a 500 μm diameter mirror coating that absorbs only 1% of the incident power, the mirror layer will have a thickness of less than 0.2mm2To emit or conduct absorbed 1mW of thermal power out of the diffuser body. In contrast, an end treatment of a mirror of the same size, having thermal contact with a heat sink member, for example, of a size of at least 1mm long by 0.7mm diameter, will have an external surface area that is 13 times greater than the surface area of the mirror itself. This increased surface area for dissipation of the same 1mW light energy absorption will result in a significantly reduced heat rise. Therefore, an end treatment consisting of a material with good thermal conductivity with an external surface area at least 10 times (i.e., 1000%) the surface area of the diffuser end face is desirable.
Referring to fig. 48-51, the present invention provides a diffuser light blocking device that simultaneously satisfies all previously desired characteristics of an ideal end treatment of a diffuser. A diffuser light blocking means may be used as the light blocking means 314 discussed above in this specification.
As shown in fig. 48-51, the diffuser light blocking arrangement includes an end cap member 820 having a pocket feature 821 designed to receive and enclose a distal portion 830 of diffuser 800 having a distal end surface 801. Pocket feature 821 includes a sidewall 822 and an end reflective surface 810. The shape of pocket feature 804 generally corresponds to the outer shape of distal portion 830 of diffuser 800 to allow distal portion 830 to engage and fit within pocket feature 821. The sidewall 822 has an overlapping portion 815, the overlapping portion 815 enveloping (e.g., overlapping) the sidewall 802 of the distal portion 830 of the diffuser 800 with the length 830. The sidewalls 822 also provide a mechanism to attach the light barriers, including the end cap member 820, to the diffuser 800 while also preventing high angle non-uniform light from creating diffuser irradiance hot spots. The overlapping portion 815 of the sidewall 822 is designed to surround the sidewall 803 of the distal portion 830 of the diffuser 800 and allow the diffuser light blocking arrangement to prevent at least 95% (preferably at least 97%, more preferably at least 98%) of the light output of the distal portion 830 from escaping from the sidewall 803 of the distal portion 830. The reflective end surface 810 returns, reflects, or scatters back (collectively referred to as "return" below) light emitted from the distal end surface 801 of the diffuser 800 to the diffuser 800 while blocking any forward propagating light output from the distal end surface 801. The reflective end surface 810 returns at least 80% of the light output from the distal end surface 801 back towards the diffuser 800.
The end cap member 820 is thermally conductive to allow heat generated by absorbing light output from the distal portion 830 of the diffuser 800 to be dispersed throughout the end cap member 820. The diffuser light blocking means, including the end cap member 820, may be comprised of any opaque material that absorbs, reflects or scatters incident light back. If they are formed of a thermally conductive metal material, such as aluminum, the metal material can disperse and dissipate any thermal energy generated by absorption of the blocked light.
Referring to fig. 50-51, and in an alternative embodiment, the end cap member 820 includes a sleeve 835 and a rod 840 inserted into the sleeve 835. The sleeve 835 has an overlapping portion 815 of length 830 that provides a mechanism to attach both the diffuser 800 and the rod 840 while blocking uneven light. The rods 840 provide end reflective surfaces 810 that return light emitted from the distal end surface 801 of the diffuser 800 back toward the diffuser 800 while blocking any forward propagating light.
As noted above, advantageously, the sleeve 835 and the rod 840 are thermally conductive. It is also advantageous that the rod 840 be constructed of a thermally conductive metal material such as aluminum, gold, silver, copper, stainless steel, nickel, any suitable metal alloy, or any suitable ceramic having a high thermal conductivity to further help block transmitted light and dissipate any thermal energy generated.
The end reflective surface 810 may be formed by techniques such as, but not limited to, machining, mechanical polishing, electropolishing, chemical deposition, vacuum deposition, or application of a paint-like compound. Ideally, the reflective surface 810 should return at least 80%, and preferably more than 90%, even more preferably more than 98%, of the incident light from the distal end surface 801. In general, the more light that returns back toward diffuser 800, the less light is absorbed by end cap member 820 and the less thermal rise is observed in the components and surrounding tissue. Accordingly, the end cap member 820 should return at least 80% (preferably at least 90%, and more preferably at least 98%) of the light output from the distal end portion 830.
It is important to avoid the outer surface of the end cap member 820 exceeding 42 c and causing cellular damage to surrounding tissue. The length 831 and diameter 832 create an external surface area of the end cap member 820 of the diffuser light blocking means that is greater than the surface area of the distal end surface 801 of the diffuser 800 to help dissipate and dissipate any thermal energy generated by the absorption of incident light. Desirably, the length 831 and diameter 832 of the end cap member 820 provide an external surface area that is at least 1000% (preferably ranging from 1000% to 2000%, more preferably from 1500% to 2000%, even more preferably from 1700% to 1900%, and most preferably 1800%) of the surface area of the distal end surface 801 of the diffuser 800.
Referring to fig. 48 and 50, when the end cap member 820 is engaged with the distal portion 830, there may be a cavity or void (hereinafter collectively referred to as "void") 825 between the distal end surface 801 of the diffuser 800 and the end reflective surfaces (810, 845) of the end cap member 820. The void portions 825 can be filled with a compound that matches the index of refraction of the diffuser 800 material to further reduce the uneven irradiance by reducing TIR from light interacting with any defects in the distal end surface 801 of the diffuser 800. The compound in the void 825 may have "sticky" properties that help hold the entire assembly together. Additionally, the void 825 may be filled with a scattering material, such as a titanium oxide filled epoxy, which helps to scatter the transmitted light back into the fiber.
As described above, the diffusion of the present invention including its end cap member 820The light blocker-means may be used as the light blocker 314 discussed with respect to the cylindrical light diffusing means (e.g., 300) described above in the specification. In one example, the cylindrical light diffusing device is comprised of a fiber having a non-circular fiber core (such as a hexagonal core fiber with a 480 μm cladding OD). The non-circular optical fiber core includes a light diffusing portion and internal scattering features distributed within the optical fiber core of the light diffusing portion along a central axis of the optical fiber core, wherein the light diffusing portion provides a "top-hat" diffuse irradiance distribution, limiting longitudinal variation in radially emitted irradiance from the light diffusing portion to an average ("I0") within +/-15% of the optical irradiance. The length of the light diffusion portion of this exemplary embodiment may be 10mm, 20mm, 30mm, or 40 mm. Alternatively, such length may be any value in the range from 10mm to 40 mm. The cylindrical light diffusing device also includes a diffuser light blocking device of the present invention including an end cap member 820. In this exemplary embodiment, the end cap member is made of aluminum, has an outer diameter of 0.7mm, a length of 1.5mm, and has a pocket-like feature 821 of 1.0mm depth.