WO2016122266A1

WO2016122266A1 - Dental laser handpiece having optical structure for preventing damage of fiber optic

Info

Publication number: WO2016122266A1
Application number: PCT/KR2016/001025
Authority: WO
Inventors: 이성근
Original assignee: (주)비앤비시스템
Priority date: 2015-01-30
Filing date: 2016-01-29
Publication date: 2016-08-04
Also published as: KR101608022B1

Abstract

The present invention relates to a laser handpiece used in dentistry and, more particularly, to a dental laser handpiece having an optical structure for preventing fiber optic damage due to laser beam feedback. A dental laser handpiece having an optical structure for preventing fiber optic damage according to the present invention comprises: fiber optic through which a laser beam is transmitted; a tip for irradiating the laser beam; a reflection mirror for reflecting the laser beam being inputted and transmitting the same to the tip; and a defocusing lens for defocusing the laser beam outputted from the fiber optic and focusing the same into the reflection mirror.

Description

[Revision 19.02.2016] according to Rule 91. 치과 Dental laser handpieces with optical structure which prevents damage of optical fiber.

The present invention relates to a laser handpiece for use in the dentist, and more particularly to a dental laser handpiece having an optical structure that prevents damage to the optical fiber by the feedback of the laser beam.

Many of the characteristics of lasers are of great advantage in the medical field, increasing the demand for the use and application of lasers in the medical field.

Although the use of lasers in the medical field is largely related to dermatology, the use of lasers is now being gradually expanded in dentistry.

Decades ago, dentists used lasers, starting with CO2 lasers, and then Nd: YAG and diode lasers. However, these lasers are all used only as a surgical surgical tool for soft tissues such as gums, and ultimately, lasers cannot be used for tooth removal, plastic surgery, and the like.

As a laser that has been widely used in recent years, Er: YAG or Er: YSGG series lasers, which are 2940 nm bands, have appeared and are being used for dental procedures in earnest.

The characteristic of this laser is that the temperature of teeth increases during use because the laser absorbs water on the water instead of directly irradiating the laser with the water absorption that is rapidly increased in the 2940 nm band, thereby deleting the tooth by the explosive force of water droplets that absorb the laser energy. Necrosis of the pulp and tissue can be prevented.

Therefore, the Er: YAG laser can be used for hard tissues like teeth in addition to the soft tissue treatments of conventional lasers.

In dermatology, Er: YAG lasers have been used for a long time for dermabrasion, but in order to use them in dentistry, there are many technical improvements. In particular, dermatological procedures do not require precise movements, so laser transmission uses joint cancer. However, in the dental field, delicate movements are required in small oral cavity, so the optical fiber must be used to transmit the laser.

There are three types of Er: YAG laser-transmittable optical fibers, one of which is a tube structure, called a fluoride system, a sapphire system, and a waveguide. The silica-based fiber used for Nd: YAG or diode laser is very inexpensive, but the fiber used for Er: YAG is dozens of times more expensive than the silica-based fiber. In addition, since both ends of the laser input and output have to be polished very precisely, the mounting process on the handpiece takes considerable time and cost.

These handpieces require high-precision mechanical and optical technology because the handpiece using optical fibers must have a structure for transmitting water and air together with the irradiated laser and at the same time provide a good feeling of operation.

1 and 2 are cutaway and schematic diagrams showing an example of a dental laser handpiece structure.

As shown in FIG. 1 and FIG. 2, an optical fiber 1 for transmitting a laser beam, an air tube 2 for transmitting air, and a water tube 3 for transferring water are provided inside the dental laser handpiece. The front side is provided with the tip 4 is exposed to the laser beam irradiation to the tooth. The air of the air tube (2) and the water of the water tube (3) is strongly discharged around the front tip (4) and mixed with each other while spraying water droplets to the end of the tip (4) like a sprayer.

And inside the handpiece is arranged an optical structure for focusing the laser beam output from the optical fiber 1 to focus on the tip (4). In the optical structure for focusing the laser beam output from the optical fiber 1 on the tip 4, a reflector 5, a lens 6, and the like are used.

The laser handpiece using the optical fiber is excellent in the user's operability, but the optical fiber is very vulnerable to moisture and dust, so when foreign matter such as moisture or dust comes into contact with the end face of the optical fiber, the end face is easily damaged. The laser beam irradiated with the tooth is reflected from the tooth surface and is fed back into the optical fiber, thereby causing a problem that the damage of the optical fiber cross section is aggravated in continuous use.

Repair (ie, maintenance) of optical fiber with damaged cross sections is complicated and time consuming.

The damaged optical fiber is placed in a highly toxic solution to remove the external protective film and then polished in several steps from coarse sand to fine sandpaper. A special expensive grinder is required for the accuracy of the cross section.

Even with expensive grinders, it usually takes 2-3 hours to repair one damaged fiber, which means that maintenance costs are much higher for Er: YAG dental lasers than for Nd: YAG or diode lasers that use silica fibers. It takes high

Optical fiber damage accounts for more than 70% of total maintenance on Er: YAG dental lasers.

Therefore, preventing damage to the fiber as much as possible can ultimately lower maintenance costs, lower the price of the product, and increase user satisfaction.

3 to 6 show optical structures according to the prior art for focusing the laser beam output from the optical fiber 1 to the tip 4.

3 shows a method in which the laser beam output from the optical fiber 1 is directly incident on the curved (elliptical) reflector 5 and is reflected to focus on the tip 4.

The handpiece having the optical structure of FIG. 3 is simple in construction and inexpensive to manufacture, and is advantageous for miniaturization, but is easy to be exposed to foreign substances such as dust and moisture, which increases the risk of damage to the optical fiber, and the laser beam fed back from the tooth to the optical fiber The high risk of damaging the irradiated optical fiber makes it unsuitable for use as a dental laser handpiece.

4 shows a method in which the laser beam output from the optical fiber 1 is focused through the two

lenses

6 and 7 and focused on the tip 4 after being reflected by the planar reflector 5.

In the handpiece having the optical structure of Fig. 4, the loss ratio of the laser beam is more than 10% while using two lenses. Therefore, in order to output the laser beam of the desired output to the teeth, there is a burden to increase the specifications of the laser equipment such as a laser oscillator, a power supply, a cooling device.

FIG. 5 is a window 8 disposed between the optical fiber and the reflector 5, which is proposed to solve the problem of damage caused by foreign matter in the optical structure of FIG.

The optical structure of FIG. 5 protects the optical fiber by blocking the window 8 from accessing the optical fiber 1 with foreign matter such as moisture or dust. However, since this method cannot reduce the distance between the optical fiber 1 and the reflector 5, primary damage occurs in the window 8 instead of the optical fiber 1, and secondary damage of the window 8 occurs. The heat or debris generated during the reception eventually enters the optical fiber 1 and damages the optical fiber 1, and thus does not have a great effect.

However, since the optical structure of FIG. 5 has less damage than the optical structure of FIG. 3 and the transmission loss of the laser beam is smaller than that of FIG. 4, many handpieces use this method.

FIG. 6 illustrates a method in which the laser beam is converted into parallel light through the lens 9 in the optical fiber 1 and then reflected by a parabolic reflector 5 and focused on the tip 4.

The head of the dental laser handpiece has to be made small because it has to work in the mouth. In order to make it small, the size of the hot spot of the laser beam incident on the reflector 5 must be very small. If the hot spot is large, the size of the handpiece head becomes large, and it is difficult to make the incidence angle of the tip 4 small. If the size of the hot spot is reduced, the problem that the lens 9 having a maximum diameter of about 3 mm should be processed very precisely in the small effective area and the density of the laser beam become high will cause thermal damage to the reflector 5.

The prior art of the dental laser handpiece for connecting the laser beam delivered to the optical fiber to the tip through the optical structure is a problem that the optical fiber is easily damaged, and thus cost and time for repairing the optical fiber.

For reference, the prior art document regarding the dental laser handpiece is registered Patent No. 10-0602414 "Dental laser handpiece with a laser generator", Patent No. 10-0401420 "Erbium-Yag laser for dental Handpiece ", Korean Patent No. 10-1479611" Dental treatment laser handpiece "and the like.

The present invention has been made to solve the problem of the optical structure of the dental laser handpiece according to the prior art, it is to prevent (minimized) damage of the optical fiber to reduce the cost of maintenance to replace or repair the optical fiber The aim is to provide a dental laser handpiece with an optical structure that increases the frequency and prevents damage to the competitive optical fibers.

Dental laser handpiece having an optical structure for preventing the damage of the optical fiber according to the present invention for achieving the above object

An optical fiber to which a laser beam is transmitted;

A tip for irradiating the laser beam to the tooth;

A reflector reflecting an input laser beam to the tip;

And a defocusing lens for defocusing the laser beam output from the optical fiber to focus the reflector.

And the position where the focal point f of the defocusing lens is formed is coincident with the point where the end of the optical fiber 1 is located in the optical structure (see FIG. 3 or FIG. 5) not using a separate lens. .

Dental laser handpiece having an optical structure to prevent the damage of the optical fiber according to the present invention configured as described above the handpiece by preventing the damage of the optical fiber which occupies most of the maintenance cost of the dental laser handpiece (about 70%) Dental laser handpiece having an optical structure that prevents damage of optical fiber, which greatly reduces the cost and time required for the maintenance of the present invention, is a very useful invention for industrial development.

1 is a partial cutaway perspective view showing an example of the structure of a dental laser handpiece.

Figure 2 is a block diagram showing the internal structure of the dental laser handpiece.

3 to 6 show the optical structure of the dental laser handpiece according to the prior art.

7 shows an optical structure of a dental laser handpiece in accordance with the present invention.

8 is a view for explaining the specifications and arrangement of the preferred lens in the optical structure of the dental laser handpiece according to the present invention.

* Description of the symbols for the main parts of the drawings *

10: fiber 40: tip

50: reflecting mirror 60: defocusing lens

Hereinafter, the present invention will be described in more detail with reference to the drawings.

Since the present invention may be modified in various ways and have various forms, embodiments (or embodiments) will be described in detail in the text. However, this is not intended to limit the present invention to the specific form disclosed, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In each of the drawings, the same reference numerals, in particular, the tens and ones digits, or the same digits, tens, ones, and alphabets refer to members having the same or similar functions, and unless otherwise specified, each member in the figures The member referred to by the reference numeral may be regarded as a member conforming to these criteria.

In addition, in the drawings, the components are exaggerated in size (or thick) in size (or thick) in size (or thin) or simplified in consideration of the convenience of understanding and the like, thereby limiting the scope of protection of the present invention. It should not be.

The terminology used herein is for the purpose of describing particular embodiments (suns, aspects, and embodiments) (or embodiments) only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms “comprises” or “consists” are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, but one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

As shown in FIG. 7, a dental laser handpiece having an optical structure preventing damage to an optical fiber according to the present invention includes an optical fiber 10, a tip 40, a reflector 50, and a defocusing lens 60. Has an optical structure.

As shown in FIG. 1, the air tube 2, the water tube 3, and a housing therein are further included.

The optical fiber 10 transmits the laser beam generated by the laser oscillator to the handpiece, the tip 40 irradiates the laser beam to the external teeth, the reflector 50 and the defocusing lens 60 is A laser beam emitted from the optical fiber is focused onto the tip.

The optical structure according to the present invention differs from the optical structure according to the prior art by focusing and reflecting the laser beam passing through the defocusing lens 60 which is a convex lens out of the focal length to the elliptical reflector 50 and reflecting the tip 40. Is sent to.

The focusing position of the defocusing lens 60 is applied in the same manner as the output end position of the optical fiber 1 in the lensless method of FIG. This is because the reflector 5 can be used as it is in the case of utilizing the handpiece having the optical structure as shown in FIG.

The ellipsoidal reflector 5 as shown in FIG. 3 is correlated to the incident angle of the laser beam of the reflector 5 when the position of the optical fiber 1 and the position of the tip 4 reflected and reflected by the reflector 5 are fixed. Since a constant focal length is formed without adjusting the focal position of the defocusing lens 60 to the optical fiber 1 of FIG. 3, the handpiece of FIG. 3 can be used as it is.

In order to suppress damage of the optical fiber 10, the distance between the optical fiber 10 and the reflector 50 should be as far as possible, and when the window or the lens is disposed in the middle, the distance between this and the optical fiber should also be far. This minimizes the adverse effects on the optical fiber if damage to the window or lens occurs.

Compared with the conventional method, the distance L1 between the optical fiber 10 and the lens 60 and the distance between the lens 60 and the reflector 50 are realized the longest in the present invention.

In order to prevent damage to the optical fiber 10, the distance L1 from the optical fiber 10 to the lens 60 should be increased. However, when the distance is longer, the hot spot where the laser beam is incident on the lens 60 becomes larger. In the conventional window method (see FIG. 5), the beam continues to grow while passing through the window, thereby exceeding the effective surface incident on the reflector. In other words, in the window method, the distance between the optical fiber and the window is close, and the optical fiber damage is increased. In addition, the greater the distance between the lens and the reflector, the less damage the optical fiber and lens. Debris or smoke caused by external moisture, dust, and reflector damage from the tip touches the lens, which causes lens damage, which in turn leads to damage to the optical fiber. That is, the distance between the lens and the reflector should be increased, which is advantageous for preventing damage to the optical fiber.

In the present invention, a sufficient focal length (L2) can be secured through the lens to increase the distance, and the distance can be secured again through defocusing, thereby increasing the distance between the lens 60 and the reflector 50 to the maximum.

In addition, in FIG. 5, which is a method mainly used in the related art, the window 8 is replaced with the defocusing lens 60, and an existing reflector is used as it is.

8 is a view for explaining a method of determining the specification and position of the defocusing lens 60.

The divergence angle θ at which the laser beam is emitted from the optical fiber 10 is expressed as NA (numerical aperture) as a specification of the optical fiber, and follows the following equation.

NA = sin (θ)

θ: divergence angle from the optical fiber

At this time, the distance L1 is determined so that the laser beam is divergent and incident on the entire effective surface S of the lens 60 from the divergence angle θ.

The position where the laser beam passing through the lens 60 forms the focal point f is where the existing optical fiber is located in the optical structure of FIG. 3 or FIG. 5.

At this time, the focal length L2 of the lens 60 is related to the distance between the focal point f and the reflector 50, but the distance between the reflector 50 at the focal point f is determined according to the conventional optical structure of FIG. When the reflector is used as it is, the distance between the optical fiber 1 and the reflector 5 is the same.

The laser beam reflected by the reflector 50 is focused on the tip 40 again, where the smaller the incident angle I, the better. However, the smaller the incident angle I, the smaller the hot spot of the reflector 50, so the possibility of damage to the reflector 50 increases, and the larger the incident angle I, the larger the hot spot, but the lower the transmittance on the tip, the maximum incident angle transmitted to the tip. The incident angle I of the laser beam of the reflector in the optical fiber may be determined based on the reference. The tip material is mainly sapphire, and the incidence angle considering the refractive index of sapphire is considered as the maximum incidence angle.

That is, the position of the lens 60, that is, the focal length L2, is determined from the angle of incidence I of the laser beam to the tip 40.

When L1 and L2 regarding the position of the lens 60 are determined as described above, the radius of curvature of the lens 60 is designed using the following equation.

1 / L1 + 1 / L2 = (n-1) (1 / R1-1 / R2)

n: refractive index of the lens

R1, R2: radius of curvature of the lens

Here, when the front curvature radius R1 of the lens 60 is flat (that is, infinity), the rear curvature radius R2 value of the lens 60 can be obtained.

In the above description of the present invention, a dental laser handpiece having an optical structure for preventing damage to an optical fiber having a specific shape and structure has been described with reference to the accompanying drawings. Possible, such modifications and variations are to be construed as falling within the protection scope of the present invention.

Claims

An optical fiber to which a laser beam is transmitted;

A tip for irradiating the laser beam to the tooth;

A reflector reflecting an input laser beam to the tip;

And a defocusing lens for defocusing the laser beam output from the optical fiber to focus the reflector. 10. The dental laser handpiece having an optical structure for preventing damage to an optical fiber.
The method of claim 1,

The position where the focal point f of the defocusing lens is formed coincides with the point where the end of the optical fiber 1 is located in the optical structure (see FIG. 3 or 5) without using a separate lens. Dental laser handpiece having an optical structure to prevent damage.