JP3872226B2 - Laser therapy device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser treatment apparatus that performs treatment by irradiating a treatment site with treatment laser light.
[0002]
[Prior art]
Laser hair removal treatment is known in which the hair growing on the body is irradiated with laser light to cauterize the hair root and remove the hair. Since melanin is contained more in the periphery of the hair root than in the surrounding skin epidermis, by irradiating laser light having a wavelength that is easily absorbed by melanin, the thermal energy is dissipated to the hair root portion and the hair root is cauterized.
[0003]
[Problems to be solved by the invention]
In conventional laser hair removal treatment, irradiation conditions such as laser light output and irradiation time are set in consideration of the difference in hair state depending on the body part, and this largely depends on the experience of the operator. If the output of the laser light is too strong or the irradiation time is set too long, the possibility of damaging the skin other than the hair roots increases. On the contrary, if the output of the laser beam is too weak or the irradiation time is not sufficient, the hair removal in the range where the laser irradiation has been performed may not be reliably and efficiently performed.
[0004]
In view of the drawbacks of the above-described conventional apparatus, the present invention can set optimal laser irradiation conditions according to the state of the treatment site without depending on the experience of the surgeon, and efficiently suppresses damage to the skin. An object of the present invention is to provide a device capable of performing treatment (hair removal).
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is characterized by having the following configuration.
[0006]
(1) In a laser treatment apparatus that performs hair removal treatment by irradiating a treatment laser beam from a laser light source, a laser beam for detection is applied to the treatment laser beam irradiation range with an output weaker than the output necessary for treatment. And a thermograph for detecting a temperature distribution that changes due to the irradiation of the detection laser beam, and the pore position and the thickness of the hair at each position based on the output signal of the thermograph Detecting means for detecting the irradiation, and irradiation variable means for changing the irradiation condition of the treatment laser light based on the detection result.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic external view of a laser treatment apparatus for hair removal according to an embodiment.
[0015]
Reference numeral 1 denotes a laser device main body, and a control unit (to be described later), a hair removal laser light source, and the like are accommodated in the device main body 1. Reference numeral 7 is a control panel for inputting various setting conditions such as laser irradiation conditions, and 8 is a foot switch for transmitting a trigger signal for irradiating a laser beam. A key switch 9 is provided.
[0016]
Reference numeral 2 denotes an optical fiber for guiding laser light emitted from the apparatus main body 1, and 3 denotes a handpiece unit having a laser irradiation port. The handpiece unit 3 is provided with a thermograph 6 of a CCD camera that is sensitive to infrared rays. The thermograph 6 detects the position of the pores (follicles) and the thickness of the hair depending on the temperature difference of the skin surface before performing the hair removal treatment. (This recognition method will be described in detail later).
[0017]
FIG. 2 is a diagram showing a configuration of the handpiece unit 3. The handpiece unit 3 includes a scanner unit 11 and a handpiece head unit 12. In the scanner unit 11, a lens 10 (see FIG. 3) for shaping the hair removal laser light that has passed through the optical fiber 2 into a small spot having a diameter of about 2 mm on the irradiated part, and the laser light in the treatment part in the XY direction. Drive mirrors 13a and 13b for scanning, drive motors 14a and 14b, and a lens 15 inserted into and removed from the optical path of the laser beam are provided. The lens 15 is inserted into the optical path when recognizing the position of the pores, and diffuses the laser light on the skin surface. The lens 15 is inserted and removed by the drive motor 16. Moreover, the handpiece head part 12 is provided with the head front-end | tip part 17 for making it contact | abut to skin and stabilizing a handpiece unit.
[0018]
FIG. 3 is a principal block diagram showing the configuration of the control system and the optical system. A control unit 20 controls the entire apparatus. Reference numeral 21 denotes a laser light source for hair removal. In this embodiment, an alexandrite laser (wavelength 755 nm) is used. The laser light from the laser light source 21 is reflected by the mirrors 22 and 23 and then condensed and incident on the optical fiber 2 by the lens 28. A scanner controller 24 controls driving of the drive motors 14a and 14b. A control signal from the scanner controller 24 is transmitted to the scanner unit 11 via the connector unit 5 and the cable 4, and the drive mirrors 13a and 13b are controlled to swing. Reference numeral 25 denotes an image processing unit for processing the image obtained by the thermograph 6 and detecting the position and size of the pores (hair thickness).
[0019]
A method for detecting the position and size of the pores from the image by the thermograph 6 will be described.
[0020]
In laser hair removal treatment, the skin is irradiated with laser light having a wavelength that is easily absorbed by melanin, and the thermal energy of the laser light absorbed by melanin is radiated to the hair root, thereby cauterizing the hair root and performing hair removal. Therefore, the more concentrated melanin is, the more the thermal energy of the laser light is absorbed, and the temperature of that portion temporarily increases. Melanin is distributed along the skin surface (epithelium), hair roots, and pores, but the density of the distribution is much higher in the hair roots than in others, and the amount of energy absorbed is large. In general, the thicker the hair, the greater the amount of melanin around the root of the hair. Therefore, when the laser beam is irradiated, the thicker hair has a larger amount of heat than the thinner hair. Utilizing this fact, a treatment laser beam having a weak output (not causing damage to the skin) is diffused and irradiated in advance on a predetermined region of the skin surface, which is a laser beam irradiation range at the time of treatment. The temperature distribution in that region is imaged by the thermograph 6. By identifying where the temperature is high based on this image, the position of the pore can be specified, and the thickness and size of the hair at each position can be detected by the size of the central temperature area.
[0021]
FIG. 4 is a diagram schematically showing the state of the temperature distribution obtained by processing the image by the thermograph 6 in the image processing unit 25. Reference numeral 30 denotes an irradiation range of the laser beam. 31 is an isotherm, and the temperature is higher in the inner isotherm. Therefore, in this example, the centers A, B, C, and D of each isotherm 31 are detected as the positions of the pores. Further, from the size of the isothermal area at the center, the pores are detected as the thicknesses E, F, G, and H at each position as shown in the figure.
[0022]
In addition, when using the thermograph 6, it is desirable to perform the imaging within the thermal relaxation time of the hair root after the laser beam is irradiated. The thermal relaxation time means that when laser light is irradiated onto a target (in this case, melanin), the temperature distribution around the target becomes a Gaussian distribution having a width determined by the diameter, but the central temperature of the distribution falls to 50%. It is time until.
[0023]
Generally, the thermal relaxation time of melanin is about 10 nsec to 1 μsec, and the thermal relaxation time of the hair root is about 40 msec to 100 msec when the diameter of the hair root is 200 to 400 μm. After irradiating the laser beam to the target, the temperature of melanin increases rapidly until the thermal relaxation time, but when the thermal relaxation time is exceeded, the temperature gradually changes while radiating heat. At this time, the heat energy radiated from the melanin is transmitted to the hair root, and the temperature rapidly rises in the same manner until the heat relaxation time of the hair root. As a result, while the thermal relaxation time of the hair root continues, a temperature difference from the surroundings is likely to occur. When the thermal relaxation time of the hair root is exceeded, the temperature rise at the hair root is suppressed, and at the same time, heat is conducted to the surroundings. For this reason, after exceeding the heat relaxation time of the hair root for a long time, the temperature difference between the pores and the surroundings is less likely to appear, and it is considered difficult to recognize the pores.
[0024]
Detection of the position and size of the pores can also be performed as follows. For example, a CCD camera having sensitivity in the visible region is used instead of a thermographic CCD camera, and an actual skin state irradiated with the hair removal laser light is imaged. The position of the pores, the thickness of the hair, etc. are recognized by the color and shape obtained from the captured image. In addition, it irradiates light that emits fluorescence in response to melanin, or pre-administers a fluorescent agent that reacts to melanin and does not harm the living body, and then images the state, and the position and thickness of pores from the fluorescence emission Is detected.
[0025]
Next, operation in laser therapy will be described. The surgeon shave hair in a range where hair removal is performed before irradiating the laser beam, and applies a cooling gel or the like to the skin. Next, after making various necessary settings on the control panel 7 with the control panel 7, the head tip 17 of the handpiece unit 3 is brought into contact with the skin so that the target treatment area is below the handpiece head 12. Let In this state, the handpiece unit 3 is stabilized, and a scan switch (not shown) for recognizing the pore position of the control panel 7 is pressed.
[0026]
When the scan switch is pressed, the control unit 20 drives the drive motor 16 to insert the lens 15 on the laser beam path, and then the laser beam having a weaker output than the laser light source 21 (1 for the laser output used for treatment). / 20 to about 1/100) is emitted as laser light for pore position recognition. Generally, the output of laser light used for hair removal is 10 to 40 J / cm ² , and therefore, the output of laser light for pore position recognition is preferably about 0.1 to ² J / cm ² .
[0027]
Laser light for recognizing the pore position emitted from the laser light source 21 is guided to the handpiece unit 3 by the optical fiber 2. The laser light emitted from the optical fiber 2 is reduced to a diameter of about 1 to 2 mm by the lens 10, but is diffused by the lens 15 to irradiate a region having a diameter of about 2 cm at a time. At this time, the drive mirrors 13a and 13b are placed at the reference position by initialization.
[0028]
When the laser beam is applied to the skin, as described above, the thermal energy from the laser beam is accumulated in melanin, and a temperature difference between the hair root and its surroundings occurs. The region irradiated with the laser is imaged by the thermograph 6 at a timing within the thermal relaxation time of the hair root, and the temperature distribution information is obtained by the image processing unit 25. From this temperature distribution information, the position and size of the pores are detected as described above. The position of each pore is replaced with a coordinate position, and the position information and the size information at each position are stored in the control unit 20.
[0029]
When the detection by the image processing means 25 is completed, the control unit 20 informs the operator that the position recognition of the pore has been completed by an electronic sound or a monitor (not shown) provided in the control panel 7. At the same time, the lens 15 is retracted from the laser beam path, and irradiation by scanning with a hair removal laser beam having a diameter of 1 to 2 mm is enabled.
[0030]
The surgeon presses the foot switch 8 while holding the handpiece unit 3 to give an irradiation command of the hair removal laser light to the apparatus. When the command signal is input, the scanner controller 24 drives the drive motors 14 a and 14 b based on the stored position information, and the control unit 20 controls the timing of laser emission from the laser light source 21. In the example of FIG. 4, first, the scanner controller 24 adjusts the angles of the drive mirrors 13a and 13b so that the laser beam is irradiated to the pore position A. The control unit 20 emits laser light from the laser light source 1 at the timing when the angle adjustment is completed. Next, the laser light is emitted by adjusting the angles of the drive mirrors 13a and 13b so that the laser beam is irradiated to the pore position B, and this is sequentially performed to the pore positions C and D. In this way, the laser light is selectively emitted toward the pore positions A to D by the emission of the laser light and the control of the scan, so that damage to surrounding tissues can be reduced.
[0031]
Further, at this time, the control unit 20 controls the driving of the laser light source 21 so as to change the irradiation conditions of the optimum laser irradiation output and irradiation time according to the thickness of the hair for each pore position.
[0032]
The laser irradiation output and irradiation time corresponding to the hair thickness will be described. The principle of laser hair removal is that laser light is absorbed by melanin present around the hair root, and the stored heat is transmitted to the hair root to be destroyed. The laser irradiation at this time needs to irradiate with energy sufficient to burn the hair root in such a time that does not destroy melanin and epithelium in a time longer than the heat relaxation time of melanin and skin and shorter than the heat relaxation time of the hair root. The thermal relaxation time of melanin is about 10 nsec to 1 μsec, the thermal relaxation time of the epithelium is 3 to 10 msec, and the thermal relaxation time of the hair root is about 40 msec to 100 msec. However, the thermal relaxation time described above varies depending on the thickness of the hair root (thickness of the hair). When the laser irradiation time is longer than that time, the stored energy is diffused to the surroundings, and the effect of destroying the hair root is reduced. Therefore, the laser irradiation time is adjusted in the range of 10 to 40 msec. Furthermore, in order to perform efficient hair removal without unnecessarily causing an increase in the temperature of the skin, a laser having an output corresponding to the thickness of the hair root is irradiated. What is necessary is just to obtain | require quantitatively beforehand the optimal laser output and irradiation time according to the thickness of a hair root, and to make it determine based on the data.
[0033]
The example of selectively irradiating the laser beam for each pore position has been described above. However, the laser beam having a diameter of 10 to 20 mm without the scanner mechanism is irradiated to treat all the hair roots in the region ( Even in the case of batch irradiation to be ablated, the device detects the thickness of each hair in the area, and the device automatically sets the optimal laser light irradiation conditions based on that information, so that inexperienced people However, it is possible to efficiently treat (hair removal) while suppressing damage to the skin as much as possible. That is, even in the case of collective irradiation, the laser output and irradiation time are set for each region according to the thickest hair thickness. Thereby, appropriate laser irradiation is performed at least for each region. When performing batch irradiation with the apparatus of this embodiment, the lens 15 may be inserted while the hair removal laser light is irradiated.
[0034]
In addition, although the thickness of the hair may vary depending on the area of the hand, foot, etc., for a patient with less variation in the thickness of the hair in the same area, batch irradiation may complicate the device mechanism. In some cases, it is economically advantageous.
[0035]
Furthermore, if a mechanism for switching between the selective irradiation mode and the collective irradiation mode is provided, and the mode is properly used according to the judgment of the operator, hair removal is performed more efficiently.
[0036]
As described above, in this embodiment, alexandrite laser light is used as the laser light. However, the present invention is not limited to this, and any laser light having a wavelength that can be easily absorbed by melanin and reaches melanin around the hair root may be used. Specific examples include a ruby laser and a diode laser.
[0037]
【The invention's effect】
As described above, according to the present invention, since the laser irradiation condition is set according to the thickness of the hair in the laser irradiation region, the damage to the skin can be achieved without depending on the operator's experience. Efficient hair removal can be performed while reducing hair loss.
Moreover, since appropriate laser irradiation conditions for each hair are set, hair removal can be performed more reliably. Furthermore, it is not necessary to excessively increase the energy per unit time required for laser hair removal, and it is possible to improve the hair removal processing capacity by downsizing the apparatus.
[Brief description of the drawings]
FIG. 1 is a diagram showing an external appearance of an apparatus.
FIG. 2 is a diagram showing details of a handpiece unit.
FIG. 3 is a block diagram showing an optical system and a control system.
FIG. 4 is a schematic diagram showing temperature distribution on the skin when laser light is irradiated.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Apparatus main body 3 Handpiece unit 6 CCD camera 7 Control panel 8 Foot switch 20 Control part 21 Laser light source 24 Scanner controller 25 Image processing part

Claims (1)

  In a laser treatment apparatus that performs hair removal treatment by irradiating a treatment laser beam from a laser light source, the treatment laser beam is emitted as a detection laser beam to an irradiation range of the treatment laser beam at an output weaker than an output necessary for treatment. It has a detection laser beam irradiation means and a thermograph that detects a temperature distribution that changes due to irradiation of the detection laser beam, and detects the pore position and the thickness of the hair at each position based on the output signal of the thermograph. A laser treatment apparatus comprising: a detection unit; and an irradiation variable unit that varies an irradiation condition of the treatment laser light based on the detection result.

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