JP7066163B2 - Laser line generator - Google Patents

Description

The present invention relates to a laser line generator.

When it is desired to perform three-dimensional measurement of a measurement object in a non-contact manner, an optical cutting method can be mentioned as one of the measurement methods. The light cutting method is a measurement method in which linear (line-shaped) light is projected onto an object and the three-dimensional shape of the object is obtained from the shape of the projected light.

Examples of the device that generates and emits line-shaped light used in such an optical cutting method include the laser line generator described in Patent Document 1.

The laser line generator described in Patent Document 1 has an incident surface that focuses or parallelizes the captured light, and a wedge-shaped emitting surface that linearly irradiates the light. Further, the tip of the wedge-shaped exit surface is formed in a circular chamfer shape, and is manufactured by molding with glass or resin.

Japanese Unexamined Patent Publication No. 2008-08295

However, in the laser line generator described in Patent Document 1, since light is directly incident on the collimator and the exit lens from the laser light source, the outer diameter dimension of the laser line generator is determined by the diameter of the optical component such as the collimator and the exit lens. It will be decided. The outer diameter of such a collimator and an exit lens is about 6 mm. Therefore, when the object of 3D measurement is small (for example, an object with an external dimension of about several mm) and the laser line generator is used for a device with a small diameter (about several mm) such as for endoscopes, the tube of the device. I couldn't insert the laser line generator into. Therefore, it was impossible to measure a small object by the optical cutting method.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser line generator capable of three-dimensional measurement of a small object by a light cutting method.

The above problems are solved by the following invention. That is, in the laser line generator of the present invention, the components are at least a GRIN lens or a graded index optical fiber, an optical fiber , a laser light transmitter or a coreless optical fiber , and the optical fiber is a single mode fiber and a GRIN lens . Alternatively, a laser light transmitter or a coreless optical fiber is arranged on the emission end side of the graded index optical fiber, the optical surfaces of the components are joined to each other, and the outer diameters of the components except the optical fiber are all the same. , Laser light propagates inside the optical fiber, the light propagated from the optical fiber is converted to parallel light by the GRIN lens or graded index optical fiber, and the GRIN lens or graded to the laser light transmitter or coreless optical fiber. Parallel light is incident from the index optical fiber, and the end opposite to the end of the laser light transmitter or coreless optical fiber into which parallel light is incident has a wedge-shaped flat surface, and the wedge-shaped tip is curved. It is formed into a shape, and is characterized in that parallel light is emitted linearly from the opposite end and in the optical axis direction of a laser light transmitter or a coreless optical fiber .

According to the laser line generator of the present invention, it is possible to reduce the size by using an optical fiber as an optical component for propagating laser light. Therefore, by using the laser line generator of the present application, it is possible to measure a small object by the optical cutting method.

(a) It is a front view schematically showing the laser line generator which concerns on embodiment and Example of this invention. (b) It is a left side view of FIG. 1 (a). (c) FIG. 1 (b) is a plan view when viewed from above. (a) It is a front view which shows the laser light emitting part in the laser line generator of FIG. (b) It is a partially enlarged side view of the circle A portion in FIG. 1 (b). (c) It is a partially enlarged plan view of the circle B portion in FIG. 1 (c). It is a perspective view schematically showing the split sleeve attached to the laser line generator shown in FIG. 1. FIG. 3 is a plan view showing a state in which a split sleeve is attached to the laser line generator shown in FIG. 1 (c). FIG. 3 is a principle diagram of emitting linear laser light from the end of the laser beam emitting portion in the laser line generator of FIG. 1. (a) It is explanatory drawing which shows the emission state of the linear laser light from the laser line generator of FIG. 1 (b) macroscopically and schematically. (b) FIG. 6 (a) is a plan view when viewed from above. It is explanatory drawing which shows typically the light intensity distribution in the linear laser beam emitted from the laser line generator of FIG. It is an image which shows the linear laser beam emitted from the laser line generator which concerns on embodiment of this invention. It is a light intensity distribution graph of the linear laser beam emitted from the laser line generator which concerns on embodiment of this invention. (a) It is a front view schematically showing the laser line generator which concerns on another embodiment of this invention. (b) It is a left side view of FIG. 10 (a). (c) FIG. 10 (b) is a plan view when viewed from above. (a) It is a front view which shows the laser light emission part in the laser line generator of FIG. (b) It is a partially enlarged side view of the circle C portion in FIG. 10 (b). (c) It is a partially enlarged plan view of the circle D portion in FIG. 10 (c).

The first feature of this embodiment is that the components of the laser line generator are at least a GRIN lens or a graded index optical fiber, an optical fiber , a laser light transmitter or a coreless optical fiber , and the optical fiber is in a single mode. It is a fiber, and a laser light transmitter or a coreless optical fiber is arranged on the emission end side of a GRIN lens or a graded index optical fiber, and the optical surfaces of the components are joined to each other. All have the same diameter, the laser light propagates inside the optical fiber, the laser light propagated from the optical fiber is converted to parallel light by a GRIN lens or graded index optical fiber, and the laser light transmitter or coreless optical fiber. The end of the laser beam transmitter or coreless optical fiber to which parallel light is incident from the GRIN lens or graded index optical fiber and the end opposite to the end of the coreless optical fiber has a wedge-shaped flat surface portion. Further, the tip of the wedge shape is formed into a curved shape, and parallel light is emitted linearly from the opposite end portion in the optical axis direction of the laser light transmitter or the coreless optical fiber .

According to this configuration, it is possible to reduce the size by using an optical fiber as an optical component for propagating laser light. Therefore, by using the laser line generator of the present embodiment, it is possible to measure a small object by the optical cutting method.

Further , by increasing the number of components of the laser line generator, it is possible to increase the number of joints between the components and shorten the longitudinal dimension per component in the propagation direction of the laser beam. Therefore, when the object of 3D measurement by the optical cutting method is small (for example, the object with external dimensions of about several mm) and the laser line generator is used for a device with a small diameter (about several mm) such as for endoscopes. In addition, it is possible to realize a laser line generator that can prevent breakage and breakage of components.

The second feature of this embodiment is that the cross-sectional shape of the component in the direction perpendicular to the propagation direction of the laser beam is circular, and the outer diameter is 125 μm or more and 2.0 mm or less.

According to these configurations, the diameter of the laser line generator can be reduced, so that a suitable laser line generator can be realized by measuring the optical cutting method of a small object.

The third feature of the present embodiment is that the optical surfaces of the components are joined to each other by an adhesive matching the refractive index of the portion of the component where the laser beam propagates.

According to this configuration, Fresnel reflection on the optical surface between the components can be prevented, and the generation of return light and stray light can be prevented.

In the present invention, the "optical surface" refers to a boundary surface between components and is also referred to as an optical surface.

The fourth feature of this embodiment is that the components are held by the sleeve.

According to this configuration, it is possible to hold the components of the laser line generator, and when the laser line generator is inserted into the tube of a small-diameter device, the contact between the tube and the components of the laser line generator is established. It is prevented and damage to components can be prevented. Further, since the components of the laser line generator are held by the sleeve, the optical axes of the components can be aligned with each other, and the assembly of the laser line generator becomes easy.

The fifth feature of this embodiment is that the fan angle of the parallel light emitted in a straight line is 60 ° ± 30 °, the light intensity differs between the central part and the end part, and the light intensity in the central part is the maximum. It is a point of 70% or more and less than 100% of the light intensity value.

According to this configuration, it is possible to set a suitable fan angle by measuring the optical cutting method of a small object. Further, it is possible to allow the occurrence of variation in the light intensity of the laser beam at the fan angle. Therefore, it is possible to facilitate the manufacture of the laser line generator, improve mass productivity, and improve the yield.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7. As shown in FIG. 1, the laser line generator 1 of the present embodiment includes at least a GRIN lens or a graded index optical fiber 3 and components of the optical fiber 2. Further, in the form of FIG. 1, a ferrule 4 and a laser beam emitting unit 5 are further provided as components. Further, the optical surfaces of the respective components are joined by an adhesive or fusion. In the present embodiment, the "optical surface" refers to a boundary surface between components and is also referred to as an optical surface.

From FIG. 1, a light source (not shown) is arranged at the end of the optical fiber 2 on the laser beam incident side (left side of FIG. 1B or FIG. 1C), and the laser beam is incident from the light source. The light source is a semiconductor laser element called a laser diode (LD), and examples of the wavelength include 405 nm to 1620 nm for three-dimensional measurement by the optical cutting method.

The optical fiber 2 is composed of a core and a clad having a refractive index lower than that of the core, and the clad surrounds the core. Further, the optical fiber 2 is a single mode (SM: Single Mode) type optical fiber, and for example, a quartz optical fiber can be used. A laser beam is incident on the laser beam incident side end of the optical fiber 2 from a light source, and the incident laser beam propagates inside the core of the optical fiber 2 (not shown). The outer diameter of the clad is 125 μm, and the periphery of the clad is coated. The length L2 of the optical fiber 2 shown in FIG. 1 in the optical axis oa direction can be set to an arbitrary length. Further, as the optical fiber 2, a single mode type optical fiber having a clad outer diameter of 80 μm may be used.

Ferrule 4 is a cylindrical component having a through hole on the central axis (that is, the optical axis oa), and is made of zirconia (ZrO ₂ ), ceramics containing alumina as a main component, metals such as stainless steel (SUS), quartz, or quartz. It is made of plastic such as liquid crystal polymer (LCP). The optical fiber 2 portion from which the coating has been removed is inserted into the through hole. Therefore, the length L2 of the optical fiber 2 can be said to be the length from one end side of the optical fiber 2 to the end portion inserted into the ferrule 4.

The length L4 of the ferrule 4 in the optical axis oa direction can be set to about 6.0 mm or the like. Further, the outer diameter of the ferrule 4 is set to 1.0 mm or more and 2.0 mm or less.

Further, a GRIN lens or a graded index optical fiber 3 is bonded to the end of the ferrule 4 and the end of the optical fiber inserted inside the ferrule 4. The laser light propagating in the optical fiber 2 is incident on the GRIN lens or the graded index optical fiber 3 and converted into parallel light inside the GRIN lens or the graded index optical fiber 3. The GRIN lens 3 is a cylindrical radial index distribution type (GRIN: GRadient INdex) lens whose refractive index continuously increases as it approaches the central portion (optical axis oa). The outer diameter is set to 1.0 mm or more and 2.0 mm or less.

When the lens length of the GRIN lens (that is, the length L3 in the optical axis oa direction) is set to 0.25P (P: GRIN lens pitch), or when it is set to an odd multiple of 0.25P, the light is incident from the optical fiber 2. The laser light is converted into parallel light and incident on the laser light emitting unit 5. Therefore, since the laser beam is optically coupled to the laser beam emitting unit 5 without spreading, it is possible to suppress a decrease in the light propagation efficiency. The L3 can be set to about 2.6 mm as an example. Further, the beam waist (Beam Waist) diameter 2ω (see FIG. 5) of the laser beam when it is incident on the laser beam emitting portion 5 from the GRIN lens is set to about 0.1 mm.

Further, the GRIN lens may be replaced with a graded index (GI) optical fiber. The graded index optical fiber is composed of a clad and a core whose refractive index distribution is adjusted so that the refractive index at the center is high and gradually decreases toward the outside. When the graded index optical fiber 3 is used, the length L3 may be set to one-fourth or an odd multiple of one-fourth of the meandering period of the laser beam propagating in the core of the graded index optical fiber. good. As an example, in the case of a graded index optical fiber having a core diameter of 105 μm and a clad outer diameter of 125 μm, L3 is set to 0.63 mm. The outer diameter of the graded index optical fiber is 125 μm. Hereinafter, the graded index optical fiber will be referred to as GIF as necessary.

Further, the columnar laser beam emitting portion 5 is joined and arranged on the emission end side of the GRIN lens or GIF3 (the right end portion of the GRIN lens or GIF3 in FIGS. 1B or 1C). .. The laser light emitting unit 5 is composed of a laser light transmitter or a coreless optical fiber made of glass having a uniform refractive index (refractive index distribution is flat). The outer diameter of the laser beam emitting unit 5 is set to 125 μm or more and 2.0 mm or less.

From the GRIN lens or GIF3, parallel light is incident on the laser light transmitter or the coreless optical fiber which is the laser light emitting unit 5. As shown in FIGS. 2 and 5, at the end opposite to the end of the laser beam transmitter or coreless optical fiber into which parallel light is incident, two plane portions 5a, line-symmetrically with respect to the optical axis oa, 5a is formed, and the end portion of the laser beam emitting portion 5 is formed into a wedge shape by the two flat surface portions 5a and 5a. Furthermore, the tip of the wedge shape (the peak portion formed by the two flat surfaces 5a and 5a) is formed into a curved surface shape with an arbitrary radius of curvature R5b, and the curved surface portion 5b becomes the two flat surface portions 5a and 5a. Each is formed in a continuous manner.

From FIGS. 2 (b) and 2 (c), the curved surface portion 5b is formed by the radius of curvature R5b when viewed in the depth direction of FIG. 2 (c). Further, when viewed in the depth direction of FIG. 2 (b) (that is, the direction shown in FIG. 2 (c)), the tip of the curved surface portion 5b is formed linearly in the direction perpendicular to the optical axis oa. Therefore, the curved surface portion 5b has a partially cylindrical shape, and is formed in a continuous manner with the two flat surface portions 5a and 5a.

The two flat surface portions 5a and 5a and the curved surface portion 5b are formed by polishing or processing with a CO ₂ laser or the like. Further, the formation angle θ5a of the two plane portions 5a and 5a (see FIG. 2B) is about 60 ° to 110 ° depending on the laser beam emitted from the GRIN lens or GIF3 and the desired line spread angle. The radius of curvature R5b is set to about 5.0 μm to 1.0 mm, respectively.

The parallel light propagating inside the GRIN lens or GIF3 and incident on the laser light emitting unit 5 is emitted as linear laser light from the end of the laser light emitting unit 5 as shown in FIGS. 5 and 6. .. The parallel light incident from the GRIN lens or the GIF 3 spreads linearly and is emitted when passing through the laser light emitting unit 5. Note that FIG. 5 shows parallel light incident from the GRIN lens or GIF3 on behalf of the six optical paths 7a, 7b, 7c, 7d, 7e, and 7f for convenience of explanation. Further, in FIG. 6, only the laser light after propagating to the laser light emitting unit 5 is shown.

From FIG. 5, the laser beams 7a, 7b, 7e, and 7f incident on the flat surface portions 5a and 5a are refracted on the flat surface portions 5a and 5a according to Snell's law and irradiated to the irradiation surface 8. Similarly, the laser beams 7c and 7d incident on the curved surface portion 5b are refracted on the curved surface portion 5b and irradiated to the irradiation surface 8, respectively. In this case, the laser beam emitted at the boundary between the flat surface portions 5a and 5a and the curved surface portion 5b (7b and 7e in the case of FIG. 5) has a width WL on the irradiation surface 8 of the laser beam emitted linearly. It becomes a factor to decide. Further, as a factor for determining the width WL, as shown in FIG. 5, the distance ZL from the tip of the laser beam emitting unit 5 to the irradiation surface 8 can be mentioned.

Therefore, when viewed macroscopically as shown in FIG. 6, the laser beam preferably has a constant width as shown in FIG. 6 (b), and the spread angle (fan) as shown in FIG. 6 (a) in the orthogonal direction. Angle: Fan angle) θ is emitted in a straight line. By being emitted and irradiating the irradiation surface 8 with a linear laser beam, the linear laser beam is projected onto the object, and three-dimensional measurement by the optical cutting method becomes possible. Although the irradiation surface 8 is a flat surface in FIG. 5, linear laser light can be applied to various surfaces such as uneven surfaces and curved surfaces according to the external shape of the object to be measured in three dimensions.

When the laser line generator 1 is used for optical cutting method measurement of a small object with an external dimension of about several mm, it is possible to set the fan angle θ to 60 ° ± 30 ° when the ZL is set to 20 mm to 50 mm. A suitable fan angle can be set by measuring the optical cutting method for the entire small object. The reason is that when the ZL is 20 mm to 50 mm, by setting the fan angle θ to 60 ° ± 30 °, it is possible to irradiate the entire width of a small object with an external dimension of about several mm with a linear laser beam. Because of that.

Further, FIG. 7 schematically shows the light intensity distribution at the width WL in the linear laser light emitted from the laser line generator 1. As shown in FIG. 7, the distribution of light intensity differs between the central portion and the end portion, and depending on the design of the laser line generator 1, the light intensity in the central portion is 70% or more and less than 100% of the maximum light intensity value. , Is allowed in this embodiment. In the present embodiment, the light intensity at either end or both ends is the maximum light intensity value. The applicant has confirmed after verification that the light intensity in the central part is relatively lower than the maximum light intensity value.

It is desirable that the light intensity distribution, which has a uniform light intensity value over the width WL, is considered for use in three-dimensional measurement by the light cutting method. However, in reality, at the stage of manufacturing the laser line generator 1, the degree of line symmetry between the two flat surface portions 5a and the radius of curvature R5b of the curved surface portion 5a vary. Therefore, the applicant actually measured three-dimensional measurement by the optical cutting method when irradiating a small object with an external dimension of about several mm at a fan angle θ = 60 ° ± 30 °, and measured the shape of the measured object. The shapes of the actual objects were compared. As a result, even if the light intensity differs between the central part and the edge part, if the light intensity in the central part is within the range of 70% or more and less than 100% of the maximum light intensity value, the external dimension is a small object of about several mm. It was found that if it is a thing, the change in the outer shape can be accurately obtained.

Therefore, if the light intensity in the central part is within the range of 70% or more and less than 100% of the maximum light intensity value, when the external dimension of the object to be measured is about several mm, the fan angle θ = 60 ° ± 30 °. The applicant has found that it is possible to tolerate the occurrence of variation in the light intensity of the laser beam. Therefore, it is possible to facilitate the manufacture of the laser line generator 1, improve the mass productivity, and improve the yield.

On the other hand, when the variation in light intensity becomes large until the light intensity in the central part is less than 70% of the maximum light intensity value, the read pattern shape and the outer shape of the actual measured object are measured in the optical cutting 3D measurement with an external dimension of about several mm. The applicant has also confirmed through verification that the change in the outer shape of the object cannot be accurately obtained due to the difference in the shape.

The length L5 of the laser beam emitting unit 5 in the optical axis oa direction can be set to about 0.5 to 3.0 mm or the like. Note that L5 refers to the length in the optical axis oa direction from the end portion joined to the GRIN lens or GIF3 to the tip of the curved surface portion 5b (that is, the tip of the laser beam emitting portion 5).

In the laser line generator 1, the cross-sectional shape of each component in the direction perpendicular to the propagation direction of the laser beam (direction parallel to the optical axis oa) is circular, and the outer diameter is in the range of 125 μm or more and 2.0 mm or less. It will be set so that it fits inside. Further, it is more preferable to set the outer diameters of all the components except the optical fiber 2 to the same value. By setting the outer diameter in this way, the diameter of the laser line generator can be reduced, and a more suitable laser line generator can be realized for the optical cutting method measurement of the small object. In particular, by setting the upper limit of the outer diameter to 2.0 mm or less, the laser line generator 1 can be easily inserted into the tube of a device having a small diameter, which is preferable.

Further, in the laser line generator 1, the optical surfaces of the components are joined to each other by an adhesive (optical adhesive) that matches the refractive index of the portion of each component in which the laser beam propagates. More specifically, when the refractive index of the core of the optical fiber 2, which is the portion through which the laser beam propagates, the refractive index of the laser beam propagating portion of the GRIN lens or GIF3, and the refractive index of the laser beam emitting portion 5 match, the laser beam is emitted. The optical surfaces are joined together by an adhesive having a refractive index that matches the refractive index of the propagating portion. Therefore, Fresnel reflection on the optical surface between the components is prevented, and the generation of return light and stray light can be prevented.

As the adhesive, it is preferable to use an adhesive made of a photocurable resin that can be polymerized and cured on the spot by irradiating with light such as ultraviolet rays or infrared rays. The reason is that by using an adhesive made of a photocurable resin, light is irradiated while aligning the position of the optical fiber 2 inside the through hole of the ferrule 4, and the photocurable resin is cured to cure the optical fiber. This is because it is possible to fix 2. Therefore, the optical alignment work of the optical fiber 2 can be simplified, and the work can be completed in a shorter time. The light on which the photocurable resin is cured refers to light having a wavelength range of 200 nm or more and 1400 nm or less.

When using an optical adhesive, if the refractive index of the laser beam propagating portion of the component does not match the refractive index of the optical adhesive, the optical surface of the component has antireflection that matches the refractive index of the optical adhesive or the like. A film may be formed.

Instead of joining with the adhesive, the optical surfaces between the components may be joined by fusion. Regardless of the joining method such as adhesive or fusion, each component may be sequentially joined and then cut to a desired length (L3, L4, L5).

Preferably, the outer diameter of each component of the laser line generator 1 is at least twice the beam waist diameter of the laser beam propagating in the optical fiber 2. The reason is that if the outer diameter is not more than twice the beam waist, the base of the Gaussian distribution of the laser beam will be dropped without being propagated, and the shape of the laser beam will collapse from the Gaussian distribution due to the influence of diffraction. This is because it ends up.

Further, the components of the laser line generator 1 excluding the optical fiber 2 are held by the sleeve. As the sleeve, as shown in FIG. 3, a split sleeve 6 having a cylindrical outer shape and a part of the peripheral side surface being cut off is more preferable. Further, the outer diameter D6 of the split sleeve 6 shall be set to 5.0 mm or less. By holding the component with a sleeve, it becomes possible to hold the component of the laser line generator 1, and the tube and the laser line generator 1 when the laser line generator 1 is inserted into the tube of a small-diameter device. Contact with the components of the above is prevented, and damage to the components can be prevented.

Further, by holding the component of the laser line generator 1 with the sleeve, it is possible to automatically align the optical axes of the components. Therefore, the laser line generator 1 can be easily assembled.

The sleeve is formed of ceramics containing zirconia or alumina as a main component, other materials, or the like, and is further formed by the split sleeve 6 to give elasticity to the sleeve so that it can be swelled and deformed in the radial direction. Therefore, when the component is inserted into the through hole of the split sleeve 6, the component expands according to the outer diameter of each component and is mounted while being in close contact with the outer periphery of each component.

Furthermore, by setting the outer diameter D6 to 5.0 mm or less, the outer diameter of the laser line generator 1 including the sleeve can be reduced, so insert the laser line generator 1 with the sleeve into the tube of the small diameter device. I can do things. Further, by reducing the outer diameter of the sleeve to 5.0 mm or less, it is possible to realize a suitable laser line generator by measuring the optical cutting method of a small object.

The entire sleeve may be colored black to absorb the leaked light from the components of the laser line generator 1.

As described above, according to the laser line generator 1 according to the present embodiment, the size can be reduced by using the optical fiber 2 as the optical component for propagating the laser light. Therefore, by using the laser line generator 1 of the present embodiment, it is possible to measure a small object by the optical cutting method.

Further, by configuring the laser line generator 1 to have a laser light transmitter or a coreless optical fiber as a component, the number of components of the laser line generator 1 is increased, the number of joints between the components is increased, and the direction of laser light propagation is increased. The longitudinal dimension (L2, L3, L4, L5) per component can be shortened. Therefore, the object of 3D measurement by the optical cutting method is a small object (for example, an object having an external dimension of about several mm), and the laser line generator is used for a device having a small diameter (about several mm) such as for an endoscope. In this case, it is possible to realize the laser line generator 1 that can prevent the components from being broken or damaged.

The present embodiment can be variously modified based on the technical idea of the present invention. For example, another embodiment of the present invention includes the laser line generator 9 shown in FIGS. 10 and 11. The difference between the laser line generator 9 and the laser line generator 1 is that the laser light emitting unit 5 is eliminated and the GRIN lens or the end of the GIF 3 has two flat surface portions 3a and 3a as shown in FIGS. 10 and 11. , The curved surface portion 3b may be formed.

The two plane portions 3a and 3a are formed line-symmetrically with respect to the optical axis oa at the formation angle θ3a as in the case of 5a. Therefore, the end of the GRIN lens or GIF3 is formed into a wedge shape. Like θ5a, θ3a can be set from about 60 ° to 110 °.

Furthermore, the tip of the wedge shape (the peak portion formed by the two flat surfaces 3a and 3a) is formed into a curved surface shape with an arbitrary radius of curvature R3b, and the curved surface portion 3b becomes the two flat surface portions 3a and 3a. Each is formed in a continuous manner. The radius of curvature R3b can be set to about 5.0 μm to 1.0 mm like R5b. The two flat surface portions 3a and 3a and the curved surface portion 3b are also formed by polishing or processing with a CO ₂ laser or the like.

The laser light propagating inside the optical fiber 2 propagates inside the GRIN lens or GIF3 and is converted into parallel light, and is a linear laser from the end of the GRIN lens or GIF3 as shown in FIGS. 5 and 6. It is emitted as light. The light intensity distribution in the width WL in the linear laser beam emitted from the laser line generator 9 is also schematically shown as shown in FIG. 7.

Each embodiment of the present invention will be described below, but the present invention is not limited to the following examples.

In this embodiment, a laser line generator 1 composed of the components shown in FIG. 1 was manufactured, and the linear laser light emitted was observed. The optical surfaces between the components were joined with a resin optical adhesive that was cured by ultraviolet light (wavelength 200 nm to 400 nm). Further, the refractive index of the optical adhesive used was consistent with the refractive index of the core of the optical fiber 2, the central refractive index of the GRIN lens 3, and the refractive index of the laser beam emitting unit 5. A cylindrical sleeve was attached to the ferrule 4, the GRIN lens 3, and the laser beam emitting unit 5.

The optical fiber 2 was an SM type optical fiber made of quartz, and a fiber having a coating over a diameter of 250 μm was used around the clad. L2 was set to 500 mm. The wavelength of the laser beam incident from the LD was set to 600 to 630 nm. The mode field diameter (MFD) of the optical fiber 2 is φ4.0 μm.

The ferrule 4 is made of ZrO ₂ , and the L4 is set to 6.0 mm and the outer diameter is set to 1.0 mm.

The lens length L3 for converting the laser light incident on the GRIN lens 3 into parallel light was set to 2.6 mm. The outer diameter was set to 1.0 mm, and the 2ω shown in FIG. 5 was set to 0.1 mm.

A quartz glass columnar glass body having an outer diameter of 1.0 mm was used for the laser beam emitting unit 5. At the end opposite to the end to which the GRIN lens is joined, two flat portions 5a and 5a are formed in a wedge shape with θ5a = 90 ° line-symmetrically with respect to the optical axis oa. Further, the curved surface portion 5b was formed in a continuous manner with the two flat surface portions 5a and 5a at R5b = 30 μm, respectively. In addition, L5 was set to 3.0 mm.

A flat plate having a width of 490 mm (49 cm) was prepared as the irradiation surface 8, and a linear laser beam was emitted from the laser line generator 1 on the plane for observation. The ZL = 200 mm and the fan angle θ = 60 °.

FIG. 8 shows an image of a linear laser beam emitted from the laser line generator according to the present embodiment and observed. From FIG. 8, it was confirmed that a linear laser beam having a WL = about 485 mm (48.5 cm) was emitted. Further, FIG. 9 shows a light intensity distribution graph over the width WL of the laser beam shown in FIG. From FIG. 9, it was confirmed that the light intensity near both ends in FIG. 8 became the maximum light intensity value, and the light intensity in the central part was about 82% of the maximum light intensity value.

1, 9 Laser line generator 2 Optical fiber 3 GRIN lens or graded index optical fiber
3a, 5a flat surface
3b, 5b Curved surface part 4 Ferrule 5 Laser light emission part 6 split sleeve
7a, 7b, 7c, 7d, 7e, 7 Laser light 8 Irradiated surface
Outer diameter of D6 split sleeve
L2 optical fiber length
Length of L3 GRIN lens or graded index fiber optic
L4 ferrule length
Length of L5 laser beam emitting part
oa optical axis
R3b, R5b Radius of curvature of curved surface
WL The width of the laser beam emitted in a straight line at the distance ZL
Distance from the tip of the ZL laser beam emitting part to the irradiation surface θ Fan angle θ3a, θ5a Formation angle of the flat surface part
2ω beam waist diameter

Claims (5)

The components of the laser line generator are at least a GRIN lens or graded index optical fiber, an optical fiber , a laser light transmitter or a coreless optical fiber .
The optical fiber is a single mode fiber and
The laser light transmitter or the coreless optical fiber is arranged on the emission end side of the GRIN lens or the graded index optical fiber.
The optical surfaces of the components are joined together,
The outer diameters of the components except the optical fiber are all the same.
Laser light is propagated inside the optical fiber and
The laser light propagated from the optical fiber is converted into parallel light by the GRIN lens or the graded index optical fiber.
The parallel light is incident on the laser light transmitter or the coreless optical fiber from the GRIN lens or the graded index optical fiber.
The end of the laser light transmitter or the coreless optical fiber on which the parallel light is incident has a wedge-shaped flat surface portion, and the wedge-shaped tip is formed into a curved shape. ,
A laser line generator in which the parallel light is emitted linearly from the opposite end portion in the optical axis direction of the laser light transmitter or the coreless optical fiber . The laser line generator according to claim 1, wherein the component has a circular cross-sectional shape in a direction perpendicular to the propagation direction of the laser beam and an outer diameter of 125 μm or more and 2.0 mm or less. The laser line generator according to claim 1 or 2, wherein the optical surfaces of the components are joined to each other by an adhesive matching the refractive index of the portion of the component to which the laser beam propagates. The laser line generator according to any one of claims 1 to 3, wherein the component is held by a sleeve. The fan angle of the parallel light emitted linearly is 60 ° ± 30 °, the light intensity differs between the central portion and the end portion, and the light intensity in the central portion is 70% or more of the maximum light intensity value 100. The laser line generator according to any one of claims 1 to 4, which is less than%.

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