CN111478162A

CN111478162A - Laser system of oral cavity laser therapeutic instrument

Info

Publication number: CN111478162A
Application number: CN202010284080.3A
Authority: CN
Inventors: 廖庆文; 杨经纬; 朱海建
Original assignee: Zhongkang Ruixin Shenzhen Technology Co ltd
Current assignee: Zhongkang Ruixin Guangdong Technology Co ltd
Priority date: 2020-04-13
Filing date: 2020-04-13
Publication date: 2020-07-31

Abstract

The invention provides a laser system of an oral laser therapeutic instrument, which comprises a laser power supply, a laser head, a laser water cooling system, an optical fiber output system, an air water spraying system and a complete machine control system; the laser power supply is used for supplying energy to the laser head; the laser head comprises a total reflection mirror, an output mirror, a xenon lamp, a laser rod, a light gathering cavity and an optical turn; the laser water cooling system is used for cooling a laser rod and a xenon lamp of the laser; the light guide output system is used for outputting laser and consists of a beam expanding shaping lens, a coupling focusing lens and an optical fiber; the gas-water spraying system is used for spraying a gas-water mixture to the tooth tissue under the action of laser, and plays roles in reducing the tissue temperature of an irradiation area and participating in laser treatment; and the central control system is used for controlling the laser power supply, the laser water cooling system and the gas-water spraying system to perform coordination work among parameters and subsystems. The laser beam spot laser device has the advantages of stable output laser energy, good spot uniformity, high operation flexibility and the like.

Description

Laser system of oral cavity laser therapeutic instrument

Technical Field

The invention relates to a laser system of an oral laser therapeutic instrument with the laser wavelength of 2.94 mu m, in particular to a laser head and a light guide output system of a dental therapeutic instrument.

Background

At present, caries treatment mainly comprises three processes of caries removal, cavity preparation and filling, and the cavity preparation is also a necessary step for carrying out dental pulp treatment on a tooth body. In the treatment process, the turbine handpiece is a very important surgical instrument and is one of important tools which are indispensable in dentistry. However, it has not only low cutting efficiency and accuracy, but also serious drawbacks such as noise, vibration and pain caused when the turbine hand piece cuts teeth during operation, and pressure and heat generated when the turbine hand piece is ground. It is these deficiencies that make patients either refractory to treatment or willing to receive treatment only if the affliction is too severe to tolerate. Therefore, the treatment of dental diseases has attracted much attention, and the need for improving the treatment of dental diseases is increasing.

Based on the above-mentioned deficiencies and limitations of conventional surgical instruments, there is a strong desire for a better tool to supplement or even replace the function of conventional turbine handpiece in dental treatment, where laser light enters the human visual field first with its characteristic properties of high efficiency, non-contact, etc., especially with a wavelength of 2.94 μm, which is located in the infrared region and can cut enamel, dentin, carious tissue and soft tissue. YAG laser crystal generates 2.94 μm laser close to the peak of water absorption infrared ray, which can be absorbed strongly by water, and generate photoelectrolysis effect to increase water temperature rapidly, and vapor pressure is released from tissue molecules to generate tiny explosion, so that the heated target tissue is removed by explosion. The practicability and safety of 2.94 μm laser in the oral cavity field have been certified in many ways and have been approved by the U.S. Food and Drug Administration (FDA), and the relevant products in europe and america are continuously entering the chinese market.

At present, the laser dental therapeutic apparatus with 2.94 μm wave band on the market limits the repetition frequency of the laser in order to ensure higher laser pulse energy output. The reason is that 2.94 mu m laser emission transition generated by the Er-YAG laser crystal occurs between 4I11/2 state and 4I13/2 state of Er3+ ions, the pumping threshold is high, and the laser conversion efficiency is low. Therefore, large energy pumping is required to obtain higher energy output, which causes thermal lensing in the laser crystal, and increasing the repetition frequency further exacerbates the thermal lensing problem. The serious thermal lens effect is easy to cause the pulse energy reduction of the output laser and the stability reduction of the laser, and even can cause the damage of optical components in the laser seriously.

The technology of the invention introduces the design idea of unstable resonator by redesigning the laser resonant cavity, solves the problems of lower output laser pulse energy and poor stability caused by higher laser repetition existing in the similar products in the existing market, and simultaneously adopts the mode of combining the beam expanding shaping lens and the coupling focusing lens to efficiently couple the 2.94 mu m laser into the optical fiber. The defect that the laser with the wave band can only be used for transmitting the laser by the light guide arm is overcome, the output handpiece can realize 360-degree operation without dead angles in the treatment operation process, and the operation flexibility is improved.

Disclosure of Invention

In order to solve the technical problem of the invention, the adopted technical scheme is as follows: a laser system of an oral laser therapeutic instrument comprises a laser power supply, a laser system, a laser water cooling system, a gas-water spraying system and a complete machine control system; the laser power supply is used for supplying energy to the laser; the laser water cooling system is used for cooling a laser rod and a xenon lamp in the laser head; the light guide output system is used for laser output conduction; the gas-water spraying system is used for spraying a gas-water mixture to the dental tissue under the action of laser, and has the functions of reducing the temperature of the tissue and participating in laser treatment; the whole machine control system is used for controlling the laser power supply, the laser water cooling system and the gas-water spraying system to perform coordinated work among parameters and subsystems, and the laser system comprises a laser head and a light guide output system.

The laser head comprises a total reflection mirror, an output mirror, a xenon lamp, a laser rod, a light gathering cavity and an optical turn; YAG laser crystal, process into the rod-like structure, install in said condensation chamber and connect with water cooling system with the xenon lamp in parallel, the light that the xenon lamp emits is called the pumping light, gather the pumping light to the laser rod as the pumping energy to the greatest extent through the condensation chamber; the water cooling system cools the light-gathering cavity, the laser rod and the xenon lamp in the cavity; the laser power supply provides electric energy for the xenon lamp, and finally, the pulse energy, the pulse width and the repetition frequency of the output laser can be directly controlled by controlling the power of the injected electric energy of the xenon lamp and the light emitting times per second; the full-reflection cavity sheet and the output cavity sheet are arranged in parallel to two end faces of the laser rod to form a laser resonant cavity, and the number of reversed particles required by the laser rod for generating laser output is generated under the excitation of the xenon lamp; the optical turn is disposed between the laser bar and the output mirror.

The total reflection mirror and the output mirror are both white gem (Al2O3) lenses. Wherein the total reflection mirror adopts a plano-convex mirror structure, and a 2.94 mu m wave band total reflection film is plated on the convex surface; the output mirror adopts a concave-convex mirror, the concave surface is plated with a 2.94 mu m wave band 20-90% reflecting film, and the convex surface is plated with a 2.94 mu m anti-reflection film. The total reflection cavity plate and the output cavity plate can be made of materials such as YSGG crystal, YAG crystal, calcium fluoride (CaF2), magnesium fluoride (MgF2) and the like instead of white gem (Al2O 3). Types of total reflection and output mirrors may also be employed: any one of plano-plano, plano-concave, plano-convex, concave-convex, and concave-concave lenses.

The light-gathering cavity is a glass cavity filled with barium sulfate powder or polytetrafluoroethylene materials, and the light-gathering cavity can keep good stability during long-time high-energy pumping, so that the pumping efficiency of the laser rod is effectively improved. The light focusing cavity can also use a ceramic light focusing cavity, a gold-plated cavity or a silver-plated glass cavity.

The optical turn is made of stainless steel, copper, iron and other materials, and the lower end of the optical turn is controlled by a motor to be inserted into or removed from the resonant cavity.

The light guide output system consists of a beam expanding shaping lens, a coupling focusing lens and an optical fiber; the lens materials of the beam expanding shaping lens and the coupling focusing lens are as follows: white gem (Al2O3), YSGG crystal, YAG crystal, calcium fluoride (CaF2) and other materials. The beam expanding shaping lens can be composed of 2-5 lenses, and the coupling focusing lens can be a lens group or an aspherical lens. The optical fiber is selected from hollow optical fiber, fluoride optical fiber or sapphire optical fiber.

Compared with the prior art, the invention has the advantages that:

(1) the laser adopts the unstable resonator technology to compensate the thermal lens problem of the laser under the large-energy pumping, improves the repetition frequency of the laser output by the laser, effectively improves the pulse energy, and has good stability of the output laser pulse energy and more uniform laser spot energy distribution.

(2) The invention adds an optical turn in the laser. The laser generates a thermal lens problem under high energy pumping, which causes easy damage of optical devices in the laser. And the optical turn is added in the optical path, so that the damage of an optical device in the laser can be effectively reduced, and the service life of the whole laser is prolonged.

(3) The light-gathering cavity of the invention adopts barium sulfate powder or polytetrafluoroethylene material to fill the surrounding glass cavity, and the light-gathering cavity can keep good stability during long-time high-energy pumping and can keep good stability during long-time high-energy pumping, thereby laying a good foundation for the high-efficiency and stable output of the laser.

(4) The light guide output system adopts optical fiber transmission, and has the characteristics of high operation flexibility, convenience in operation and more uniform output light spot energy compared with light guide arm transmission.

Drawings

Fig. 1 is a block diagram of the structure of the therapeutic apparatus of the present invention.

Fig. 2 is a schematic optical path diagram of a light-guiding output system of a laser according to the present invention.

Detailed Description

The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.

As shown in figure 1, the invention comprises a laser system, a laser power supply, a laser water cooling system gas-water spraying system and a central control system. The central control system is used for controlling the parameters of the laser power supply, the laser water cooling system and the gas-water spraying system; the laser power supply is used for supplying electric energy to the laser heads; the laser water cooling system is used for cooling part of the laser component; the light guide output system is used for guiding the generated laser to the tooth tissue; the gas-water spraying system is used for spraying a gas-water mixture to the dental tissue under the action of laser, and has the functions of reducing the temperature of the tissue and participating in laser treatment. The key innovation of the invention is a laser system which comprises a laser head and a light guide output system, so that the laser head and the light guide output system in the laser system are explained in detail below, and other parts are basically the same as the common functions, realization and the like.

As shown in fig. 2, in the laser oscillation circuit of the laser head in the embodiment of the present invention, the laser head is composed of a total reflection mirror 1, an output cavity plate 2, a xenon lamp 3, a laser rod 4, a light collection cavity 5, an optical turn 6, a beam expanding and shaping mirror 7, a coupling focusing mirror 8 and an optical fiber 9.

The xenon lamp 3 is placed below the laser rod 4 in parallel, the laser rod and the xenon lamp are simultaneously installed in the light-gathering cavity 5 and are fixed on the inner side of the cavity in parallel, the xenon lamp provides electric energy through a laser power supply to emit pumping light, the generated pumping light enters the laser rod to pump the laser rod to the maximum extent through the diffuse reflection of the light-gathering cavity, and a diffuse reflection sheet or a diffuse reflection film is attached in the light-gathering cavity; the laser water cooling system is connected with the interior of the light-gathering cavity and provides constant-temperature cooling effect for the laser rod through circulating water flow. The total-reflection mirror 1 and the output mirror 2 are arranged in parallel with the end face of the laser rod strictly, and are mainly lenses made of a white gem (Al2O3) material, wherein the total-reflection mirror is designed into a plano-convex lens, the convex surface of the total-reflection mirror is coated with a total-reflection film of 2.94 mu m, the output mirror is designed into a concave-convex lens, the concave surface of the total-reflection mirror is coated with a reflection film of 20-90% of a 2.94 mu m wave band, and the convex surface of the total-reflection mirror is coated with an. YAG laser crystal, namely erbium-doped yttrium aluminum garnet crystal, is adopted in the laser rod, high doping is adopted in the embodiment of the invention, the concentration of Er/Y is 50 at.%, the Er/Y is used for emitting laser with the wavelength of 2.94 mu m, and anti-reflection films with the thickness of 2.94 mu m are plated on two end faces of the laser rod, so that the reflection is reduced, and the laser emission effect is better. The xenon lamp and the laser rod are parallelly arranged in the light-gathering cavity and are cooled by constant-temperature circulating water, and the cooling system is designed to adopt larger water flow so as to ensure higher cooling efficiency.

In a lamp-pumped laser system, there is still thermal deposition in the laser rod, which results in the generation of thermal gradients in the laser rod, resulting in a thermal lens effect. The concave-convex resonant cavity structure formed by the total reflection mirror and the output mirror can increase the effective film volume area in the resonant cavity so as to obtain higher pulse energy output under high repetition frequency. And a light turn 6 is inserted into the resonant cavity, the light turn is made of hard aluminum, iron and stainless steel materials, the lower end of the light turn is controlled by a motor to be inserted into or removed from the resonant cavity, the motor is connected with a central control system, and the central control system controls the light turn to be inserted into or taken out of the resonant cavity. When the thermal gradient in the crystal bar does not reach dynamic stability, the optical turn is arranged to be inserted into the resonant cavity to prevent laser oscillation and avoid damage of an optical device, and when the dynamic stability is reached, the optical turn is removed to generate stable laser pulse.

When the emergent laser penetrates through the beam expanding and shaping lens 7, the divergence angle of the laser is reduced under the action of the beam expanding and shaping lens, so that the laser is close to a parallel light beam, is focused by the coupling focusing lens and enters the optical fiber 9.

After the optimization, the laser system developed by the invention can work under the repetition frequency of 1-50 Hz, and the laser output with higher laser pulse energy is realized. In addition, the cooling system can realize long-time operation of the system. The device does not break down in a long-time operation, and the operation process is not influenced by the device.

The 2.94 μm laser is involved in the process of acting on the hard tissues of the tooth body, and the water not only cools the acting area, but also participates in the mechanical preparation mechanism of the cavity. The laser can be strongly absorbed by water, the photoelectrolysis effect is generated, the water temperature is increased rapidly, the vapor pressure is released from the tissue molecules to generate tiny explosion, and as a result, the heated target tissue is removed by the explosion. Hydroxyapatite in enamel and dentin has strong absorptivity to erbium laser, a large amount of laser energy is absorbed in the operation to remove hard tissues, the incident energy has almost no residue, high temperature damage to surrounding tissues is avoided, the ultimate tensile strength of carious tissues is lower than that of surrounding healthy enamel and dentin, and the carious tissues can be removed by the hot pressing effect caused by the erbium laser with lower energy. The invention relates to a dental laser therapeutic apparatus capable of generating 2.94 mu m wavelength with pulse width of 50-1000 mu s, repetition frequency of 1-50 Hz and pulse energy of 0-1.5J, wherein the improvement of the repetition frequency can effectively improve the treatment speed, and simultaneously has higher pulse energy output, and can effectively increase the depth of laser acting on lesion tissues so as to effectively cut off the dental tissues.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser system of an oral laser therapeutic instrument comprises a laser power supply, a laser system, a laser water cooling system, an air water spraying system and a complete machine control system; the laser power supply is used for supplying energy to the laser; the laser water cooling system is used for cooling a laser rod and a xenon lamp in the laser component; the light guide output system is used for laser output conduction, and is convenient to operate; the gas-water spraying system is used for spraying a gas-water mixture to the dental tissue under the action of laser, and has the functions of reducing the temperature of the tissue and participating in laser treatment; complete machine control system is used for controlling laser power supply the parameter and each branch system of laser water cooling system, air water spraying system coordinate work, its characterized in that, laser system includes laser head and leaded light output system:

the laser head comprises a total reflection mirror, an output mirror, a xenon lamp, a laser rod, a light gathering cavity and an optical turn; the laser rod and the xenon lamp are arranged in the condensation cavity in parallel and are connected with the water cooling system, light emitted by the xenon lamp is called pumping light, and the pumping light is converged to the laser rod to the maximum extent through the condensation cavity to be used as pumping energy; the water cooling system cools the light-gathering cavity, the laser rod and the xenon lamp in the cavity; the laser power supply provides electric energy for the xenon lamp and controls the xenon lamp and the water cooling system to work coordinately; the full-reflection cavity plate and the output cavity plate are arranged in parallel to two end faces of the laser rod, and the optical turn is arranged between the laser rod and the output mirror;

the light guide output system consists of a beam expanding shaping lens, a coupling focusing lens and an optical fiber; the output laser passes through the beam expanding shaping lens, the divergence angle of the laser is reduced under the action of the beam expanding shaping lens, the output laser is close to a parallel light beam, and the laser is focused by the coupling focusing lens and coupled into the optical fiber.

2. The laser system of claim 1, wherein: the total reflection mirror and the output mirror are made of materials including white gem (Al2O3), YSGG crystal, YAG crystal and calcium fluoride (CaF2), and the types of the total reflection mirror and the output mirror are as follows: any one of plano-plano, plano-concave, plano-convex, concave-convex, and concave-concave lenses.

3. The laser system of claim 1, wherein: the optical turn is of a thin-sheet structure made of stainless steel, copper and iron materials, and is connected with a small direct current motor which is used for controlling the optical turn to be inserted into or separated from the resonant cavity.

4. The laser system of claim 1, wherein: the light-focusing cavity is a glass cavity filled with barium sulfate powder or polytetrafluoroethylene materials around a glass core, and the glass core is replaced by a ceramic light-focusing cavity or a gold-plated and silver-plated glass light-focusing cavity.

5. The laser system of claim 1, wherein: the light guide output system consists of a beam expanding shaping lens, a coupling focusing lens and an optical fiber; wherein, the lens material of expanding beam plastic mirror, coupling focusing mirror includes: white gem (Al2O3), YSGG crystal, YAG crystal, calcium fluoride (CaF 2).

6. The laser system of claim 5, wherein the beam expanding and shaping mirror is composed of 2-5 lens groups.

7. The laser system of claim 5, wherein the coupling focusing mirror is a lens group or an aspherical mirror.

8. The laser system of claim 5, wherein the optical fiber is selected from a hollow core fiber or a fluoride fiber.