JP2022139459A - Luminaire using plastic optical fiber - Google Patents

Abstract

To provide illumination using a plastic optical fiber having a wide irradiation area, and having high irradiation uniformity.SOLUTION: In luminaire for guiding light through a plastic optical fiber comprising a core and at least one-layered clad, a numerical aperture of the optical fiber is 0.55 or more, and an incident end face and an emission end face of the fiber have respective surfaces horizontal to a fiber long axis direction, and an arithmetic average height Sa of the incident end face and the emission end face of the fiber is 20 nm or less.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to an illumination device using a plastic optical fiber, an endoscope illumination device, an ophthalmic surgery illumination probe, and a blood vessel catheter.

Plastic optical fibers are superior to glass-based optical fibers in terms of processability, handling, and manufacturing cost, and are therefore used for short-distance optical signal transmission, light guides, and the like.
In particular, illumination using plastic optical fibers used in medical applications requires a limited illumination size, a wide illumination area, and high illumination uniformity in order to reduce the burden on the living body.
In order for a lighting device using a plastic optical fiber to satisfy the above-mentioned required characteristics, for example, the end face of the fiber is processed (Patent Document 1).

JP-A-2004-264394

In Patent Document 1, by roughening the end face of the optical fiber array, the reflection inside the fiber is made irregular and the irradiation uniformity is improved. However, it is not an appropriate processing method when the illumination size is limited because a single fiber cannot secure a sufficient amount of light due to reflection at the end face.
SUMMARY OF THE INVENTION A main object of the present invention is to provide illumination using a plastic optical fiber with a large irradiation area and high irradiation uniformity.

The present invention is an illumination device for guiding light through a plastic optical fiber comprising a core and at least one layer of clad, wherein the numerical aperture of the optical fiber is 0.55 or more, and the entrance end face and the exit end face of the fiber are The illumination device is characterized in that it has a horizontal plane with respect to the longitudinal direction of the fiber, and the arithmetic mean height Sa of the entrance end face and the exit end face of the fiber is 20 nm or less.

According to the present invention, it is possible to provide illumination with a wide irradiation area and high irradiation uniformity.

Hereinafter, preferred embodiments of the plastic optical fiber and the plastic optical fiber cord including the same according to the present invention will be specifically described. It can be implemented with various changes depending on the requirements.

The present invention is an illumination device for guiding light through a plastic optical fiber comprising a core and at least one layer of clad, wherein the numerical aperture of the optical fiber is 0.55 or more, and the entrance end face and the exit end face of the fiber are The illumination device is characterized in that it has a horizontal plane with respect to the longitudinal direction of the fiber, and the arithmetic surface roughness Sa of the entrance end face and the exit end face of the fiber is 20 nm or less.

In the plastic optical fiber according to the embodiment of the present invention, as the core polymer (polymer), polymethyl methacrylate (PMMA), polystyrene, copolymers mainly composed of methyl methacrylate (for example, (meth)acrylate, copolymers of (meth)acrylic acid, substituted styrene, N-substituted maleimide, etc.); The polymer preferably used is a polymer containing methyl methacrylate as a main component, that is, 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more of the repeating units constituting the polymer are derived from methyl methacrylate. It is a polymer.

The (meth)acrylic acid esters include methyl acrylate, ethyl methacrylate, butyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate, bornyl methacrylate, adamantyl methacrylate and the like, and substituted styrenes. Examples include styrene, methylstyrene, α-methylstyrene, etc. N-substituted maleimides include N-isopropylmaleimide, N-cyclohexylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-o-methylphenyl maleimide and the like.

A plurality of these copolymerization components may be used, and a small amount of components other than these may be used. In addition, a stabilizer such as an antioxidant may be contained in an amount that does not adversely affect the translucency. Among these polymers, a (co)polymer containing methyl methacrylate as a main component, particularly substantially PMMA, is most preferable from the viewpoint of productivity, translucency, environmental resistance, and the like. .

When the core is PMMA, the clad-forming polymer is preferably a vinylidene fluoride/tetrafluoroethylene copolymer, more preferably a vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene copolymer. Such a copolymer is excellent in adhesion to a core formed of PMMA, transparency and flexibility, and can reduce loss of light quantity in a bent state. In the case of having two or more clad layers, the innermost clad layer located on the core side is preferably formed of such a polymer. Here, the innermost clad refers to the clad when there is one clad, and refers to the innermost clad when the clad is formed of a plurality of layers.

The outermost clad of the plastic optical fiber according to the embodiment of the present invention preferably has a bending elastic modulus of 300 to 2000 MPa. More preferably, it is 800 to 1600 MPa. When it is 300 MPa or more, the wear resistance is further improved, and the mechanical reliability when used as a lighting device is increased. When it is 2000 MPa or less, the stress generated when bending can be reduced, the loss of light quantity in the bent state is further suppressed, and the irradiation uniformity during illumination use is further improved. Polymers having such a flexural modulus include ethylene-tetrafluoroethylene-based copolymer resins in which structural units having carbonate groups are copolymerized. The outermost clad refers to the clad when the clad has one layer, and refers to the outermost clad when the clad is formed of a plurality of layers.

In the plastic optical fiber according to the embodiment of the present invention, the entrance end face and the exit end face of the fiber have a horizontal plane with respect to the longitudinal direction of the fiber, and the arithmetic mean height Sa of the entrance end face and the exit end face of the fiber is 20 nm or less. . If the arithmetic mean height Sa of the incident and outgoing facets is greater than 20 nm, reflection and scattering occur at the facets, making it difficult to irradiate the light widely and uniformly. The arithmetic mean height of the end faces is preferably 10 nm or less. To obtain a plastic optical fiber with a smooth surface, there are a method of hot pressing, a method of dissolving the end face with a chemical solution, a method of cutting the end face, and the like. Among these methods, the method of hot-pressing the end surface is preferable from the viewpoint of forming a flat surface with high accuracy. Arithmetic mean height was determined according to ISO 25178 (2010). Using a laser microscope, the fiber end face was observed without contact.

The numerical aperture of the plastic optical fiber according to the embodiment of the present invention is preferably 0.55 or more. When the numerical aperture is 0.55 or more, the irradiation range can be widened and the irradiation uniformity can be further improved. The numerical aperture is more preferably 0.60 or more.

As a method for manufacturing a plastic optical fiber, for example, a core material and a clad material are heated and melted and extruded from a composite spinneret for concentrically forming a three-layer core/first clad/second clad structure. A composite spinning method that forms a is preferably used. Subsequently, for the purpose of improving mechanical properties, a drawing treatment of about 1.2 to 3 times is generally performed to obtain a plastic optical fiber.

A white LED is preferable as the light source of the lighting device of the present invention. A white LED has a high luminance, and in the case of an LED, heat generation in the light source is small, and heat damage at the connecting portion between the plastic optical fiber and the light source can be reduced.

An endoscope illumination device according to an embodiment of the present invention has the aforementioned plastic optical fiber and can be used in combination with an endoscope. An ophthalmic surgical illumination probe according to an embodiment of the present invention has the aforementioned plastic optical fiber as an ophthalmic surgical illumination. A vascular catheter according to an embodiment of the present invention has the aforementioned plastic optical fiber as a catheter illumination or light sensor.

EXAMPLES The present invention will be described in more detail below with reference to examples. The clad materials and the plastic optical fibers produced were evaluated by the following methods.

Flexural modulus of clad: Measured according to ASTM D790 (2010). The size of the test piece was 127 mm x 13 mm x 3.1 mm. The measurement unit of ASTM D790 is kg/cm ² , and the flexural modulus was obtained from the slope of the stress-bending displacement curve at the point where the slope becomes the largest at the initial stage of stress application, ie, the tangent line at that point.

Numerical aperture of plastic optical fiber: The numerical aperture was calculated by the following formula from the refractive index measured by the method described above.
Numerical aperture = ((refractive index of core) ² - (refractive index of cladding) ² ) ^1/2 .

Illumination Uniformity: A 1 m optical fiber was connected to an LED light source and illuminated onto a standard white plate so that the exit face of the fiber was parallel to the illuminated face. The center brightness and the distance L from the center brightness to the point where the brightness is 1/2 were evaluated relative to Example 1. FIG.

Number of flexing times to break the fiber: A load of 175 g is applied to one end of the fiber, it is supported by a mandrel with a diameter of 10 mmφ, and the other end of the fiber is continuously bent at an angle of 180° around the supporting point to break the fiber. The number of times up to was measured (average value of n = 5).

The abbreviations of the monomers used are as follows.
MMA: methyl methacrylate 2F: vinylidene fluoride 4F: tetrafluoroethylene 6F: hexafluoropropylene FVE: heptafluorovinyl ether 4FM: tetrafluoropropyl methacrylate 5FM: pentafluoropropyl methacrylate.

[Example 1]
As a clad material, a fluoride copolymer having a copolymerization ratio shown in Table 1 was supplied to a composite spinning machine. Furthermore, PMMA (refractive index 1.49) produced by continuous concentric polymerization was supplied as a core material to a composite spinning machine, and the core and clad were core-sheath composite melt-spun at 240 ° C. A fiber diameter of 1000 µm and two layers were obtained. A plastic optical fiber having a clad thickness of 5 μm was obtained. Both end faces of the obtained fiber were pressed against a flat hot press heated to 200° C. so that the both end faces of the fiber were mirror-shaped perpendicular to the longitudinal direction of the fiber. When the obtained fiber was connected to a white LED and irradiated, bright light with a uniform light intensity was obtained.

[Examples 2-3]
An optical fiber was obtained in the same manner as in Example 1 using the clad materials shown in Table 1. Both end faces of these optical fibers were treated by hot pressing.

[Comparative Examples 1 and 2]
A plastic optical fiber was obtained in the same manner as in Example 1 using the clad materials shown in Table 1. Both ends of these plastic optical fibers were roughened with sandpaper. When the resulting fiber was connected to a white LED and illuminated, the light was darker than in Example 1 and uneven.

Claims (7)

A lighting device for guiding light through a plastic optical fiber comprising a core and at least one layer of clad, wherein the numerical aperture of the optical fiber is 0.55 or more, and the entrance end face and the exit end face of the fiber are aligned with the long axis of the fiber. An illumination device having a horizontal plane with respect to a direction, and an arithmetic mean height Sa of an incident end face and an exit end face of a fiber being 20 nm or less. 2. The illumination device according to claim 1, wherein a white LED is used as the light source. 3. The illumination device according to any one of claims 1 and 2, wherein a plastic optical fiber having a core containing polymethyl methacrylate is used. 4. The illumination device according to any one of claims 1 to 3, wherein a plastic optical fiber is used in which the bending elastic modulus of the outermost clad is 300 MPa or more and 2000 MPa or less. An endoscope illumination device comprising the illumination device according to any one of claims 1 to 4. An illumination probe for ophthalmic surgery, comprising the illumination device according to any one of claims 1 to 5 as illumination for ophthalmic surgery. A blood vessel catheter having the illumination device according to any one of claims 1 to 5 as a catheter illumination or an optical sensor.