JPS5927991Y2 - Aiming device for invisible laser processing machine - Google Patents

Description

[Detailed description of the invention] This invention relates to a guide light device for accurately aiming the irradiation point of invisible laser light such as infrared laser light used in laser scalpels and other processing machines.

A CO2 laser scalpel will be described below as a specific example of an invisible laser processing device.

Normally, in a laser scalpel using a CO2 laser, a condensing lens installed at the tip of the manipulator collects CO2.
2 Laser light is made into a minute spot and irradiates the affected tissue to ablate it.

However, since the CO2 laser tip is invisible, aiming means using visible light, that is, a guide light device is required to accurately determine the ablation position.

Generally, a He-Ne laser is used as the guide light, but after passing it through a manipulator coaxially with the CO2 laser, it is focused by the above-mentioned condensing lens to obtain a high-intensity aiming spot. There is.

The problem with the guide light device lies in the method of superimposing both laser beams on the same axis.

Usually, the germanium beam is placed at a 45° angle to the optical axis.
A mirror is used to transmit the infrared laser and reflect the visible laser, and then both laser beams are superimposed on the same optical axis.

An alternative method is to provide a hole in the center of this superimposing mirror, allow the CO2 laser to pass through this hole, and let the He-
The Ne laser is reflected around the hole and superimposed.
JP-A-49-96082 and JP-A-52=664
It is proposed in Publication No. 44, and in this case, He-
It is necessary to expand the Ne laser beam to such an extent that it is reflected around the hole, or to divide it in advance so that it is reflected at two symmetrical points around the hole.

The disadvantage of the first method is that because the wavelength difference between both laser beams is large, it is almost impossible to fabricate a vapor deposited film that completely transmits or reflects both laser beams, that is, a dichroic mirror, and this results in loss of both laser beams. It is.

The disadvantage of the second method is that the expanded He-Ne laser beam is also irradiated to the center hole, so the He-Ne laser beam from the center hole is
There is a large loss in the amount of laser light, and optical adjustment for beam splitting is difficult because the optical path length of the manipulator is long in order to split the laser beam in advance so that it is reflected at two symmetrical points around the hole.

Since the current laser scalpel uses several articulated mirrors, the loss of the amount of light of both laser beams due to these articulated mirrors is quite large.

In particular, the transmittance of the condenser lens (made of ZnSe) for infrared light after anti-reflection treatment is as high as about 97%, but the transmittance for He-Ne laser is about 40%, and the loss of light amount is extremely large.

In addition to this loss, if there is a light loss in the mirror part due to the superposition of laser light, the irradiation and aiming output at the tip of the manipulator will further decrease, and in order to compensate for this, the output of both laser oscillators must be reduced. It must be increased by that amount.

This leads to an increase in the size of both laser oscillators, which goes against the demands for miniaturization and cost reduction of the laser scalpel device as a treatment device.

Normally, a small He-Ne laser with an output of 2 mW is used, but in the case of the aforementioned guide light device using a perforated mirror, in a manipulator with an eight-articulated mirror configuration, after passing through the condensing lens, The laser output is only about 0.3 mW, and under the field illumination light of the surgical site, the aiming light becomes extremely dark in practice.

The purpose of the present invention is to eliminate the defects of conventionally known guiding light devices, and to eliminate the loss of light amount of both the invisible laser and the visible hole.
It is an object of the present invention to provide an aiming device for an invisible laser processing machine whose optical members are small and inexpensive and whose optical adjustment is easy.

Embodiments of the present invention will be described below with reference to the drawings.

The figure shows an embodiment of the guide light device according to the present invention.

The He-Ne laser beam 2a emitted from the He-Ne laser oscillator 1 is incident on a pair of transparent optical wedges 7a and 7b whose opposing surfaces are parallel to each other and spaced apart by a distance l.

The incidence plane of the optical wedge 7a is perpendicular to the optical axis, but the optical wedge 7b
As shown in the figure, the output surfaces of the two laser beams have different wedge angles because they are inclined by 90-α with respect to the optical axis.

Therefore, the emitted laser beam 2b is not parallel to the optical axis AM,
These become oblique rays that intersect on the extension of the optical axis.

These pair of optical wedges 7a and 7b are housed as one body in a housing (not shown) and rotate at a constant speed around the optical axis AM.

The rotation mechanism can be easily realized using current mechanical technology, such as a small motor or a combination of a motor and gears, so a description thereof will be omitted.

By rotating these pair of optical wedges 7a and 7b, He
-Ne laser beam 2a draws a conical trajectory as shown by rays 2b and 2C.

In front of the pair of optical wedges 7a and 7b, there is a perforated mirror 5 having a center hole 6, which is placed at an angle of 45° with respect to the optical axis AM.

There is a CO2 laser oscillator 3 above the perforated mirror 5, and the center hole 6 of the perforated mirror 5 has four CO2 laser beams.
After passing through, the light is condensed by the condenser lens 8, and a minute spot is generated at the focal point F1.

On the other hand, a He-Ne laser beam 2b scanned in a conical shape,
The light 2C does not pass through the center hole 6 of the perforated mirror 5, but is irradiated onto the total reflection film 5a provided around the center hole 6, and after being reflected by the total reflection film 5a, it is reflected at a point B on the optical axis. Focus light.

This converged He--Ne laser beam generates a minute spot at the above-mentioned four-light-intensity image point F1 of the CO2 laser beam by the condensing lens 8.

In this case, the convergence point B and the focal point F1 are connected to a pair of optical wedges 7a and 7b so that they become an object point and an image point, respectively, with respect to the condenser lens 8.
The position of the convergence point B is determined by finely adjusting the interval l.

Now, assuming that the wedge angle of the opposing surfaces of the optical wedges 7a and 7b is β, the inclination angle θ□ of the laser beam emitted from the first optical wedge 7a with respect to the optical axis is θ1=sin-1(n sinβ)-
β, and the deviation h of the conical ray from the optical axis is h−”=lθ1, where n is the refractive index of the optical wedge and β is the minute angle.

Further, when the wedge angle of the output surface of the optical wedge 7b is α, the inclination angle θ2 of the output laser beam 2b with respect to the optical axis is θ2=sin
−1(n sin α)−α.

If the distance from the optical wedge 7b to the convergence point B is b, then similarly h-=bθ2, so lθ,=bθ2.

Furthermore, the optical path length is much larger than the distance l in the case of a manipulator.

Therefore, lb/1t=k>i, and the pair of optical wedges 7a
, 7b by changing the interval l very slightly, the convergence point B
The position can be adjusted with high sensitivity.

If the wedge angle α of the output surface of the optical wedge 7b is O, that is, the output surface is perpendicular to the optical axis, then the output laser beams 2b, 2
C is parallel to the optical axis AM (ie, θ2=0).

On the other hand, the refractive index of the condenser lens 8 for both laser beams is
The wavelength difference between the two laser beams is large, so they are significantly different, and therefore the focus F1 for the CO2 laser and the focus F2 for the He-Ne laser are different as shown in the figure.

Therefore, if such He-Ne parallel to the optical axis
When the laser beam is focused by the focusing lens 8, the focus F
2, and the He-
The Ne laser spot becomes defocused, resulting in a somewhat blurred enlarged image.

In the aiming device of the present invention, both laser beams can be focused on the focal point F1 by adjusting the position of the convergence point B behind the condenser lens. This is the reason why the visible laser beam is scanned in a conical shape. It is.

In addition, in the case of a laser scalpel, it is common to prepare several types of condensing lenses with different focal lengths depending on the type of surgery, and to use these interchangeably.

When the focal lengths of the condensing lenses are different, the focal point F1. Although the distance between F2 changes, the position of the convergence point B can be changed by slightly adjusting the distance l between the pair of optical wedges. can be obtained.

This is a feature of the present invention. Another reason for scanning the visible laser beam in a conical shape will be described.

If the pair of optical wedges is not rotated, the output laser beam 2b
Suppose that only a ray of light such as is imaged at the focal point F1.

When the irradiation point shifts from the focal point F0 and becomes defocused, the CO2 laser is guided along the optical axis, so the center of the defocused irradiation spot is on the optical axis. Since the laser beam is an oblique beam, the image becomes off-axis and cannot fulfill its original role as aiming light.

For this reason, the He--Ne laser beam is scanned in a conical manner so that the center of the aiming beam is on the optical axis.

In actual laser scalpel surgery, laser irradiation in such a defocused state occurs very frequently.

Note that it is not necessary to use expensive infrared materials such as Ge and Zn5e for the perforated mirror 5, and an inexpensive optical member made of beryllium copper vapor-deposited with gold, for example, can be used.

As described above, in the aiming device of the invisible laser processing machine according to the present invention, the opposing surfaces are parallel to each other and different on the optical axis between the visible light source and the perforated mirror that allows the invisible laser beam to pass through the center hole. Since a pair of rotating optical wedges having a wedge angle are provided, the visible aiming light emitted from the visible light source is scanned conically around the optical axis and does not pass through the central hole of the perforated mirror. Since it is reflected in the surrounding area and superimposed with the invisible laser beam, the optical components are smaller and cheaper than conventional ones, and the loss of light amount of both the aiming light and the invisible laser beam is reduced. Further, optical adjustment can be easily performed.

Furthermore, in the present invention, the position of the convergence point can be easily changed by slight adjustment of the distance between the pair of optical wedges, so it is possible to always match the imaging positions of the two laser beams.
High brightness aiming light can be obtained.

In addition, since the aiming device according to the present invention has the above-described configuration, it is not only useful for laser scalpels, but can also be applied to various laser processing devices, and its practicality is extremely large.

[Brief explanation of drawings]

The figure shows an embodiment of the aiming device of the invisible laser processing machine according to the present invention. 1: Visible laser, 2a, 2b, 2C: Visible laser beam, 4: CO2 laser beam, 5: Perforated mirror, 6
: center hole, pair of optical wedges 7a and 7b, AM: optical axis of visible light, MF: optical axis of superimposition of visible light and infrared light, 8: condensing lens, Fl, F2: focal point.

Claims (1)

[Scope of utility model registration request] In invisible laser processing equipment, a hole is installed at a certain angle to the optical axis so that the visible light source and the invisible laser beam pass through the central hole, and the visible aiming light is reflected at the periphery. a pair of rotating mirrors whose opposing surfaces are parallel to each other and have different wedge angles for scanning the aiming light in a conical shape around its tip axis and reflecting it around the hole of the apertured mirror; An aiming device for an invisible laser processing machine that consists of an optical wedge and guides the visible aiming light to the workpiece coaxially with the invisible laser light to confirm the irradiation area of the invisible laser light.