JPH05317328A - Laser therapeutic device - Google Patents

Abstract

PURPOSE:To sample the random polarized radiation light simply and accurately by providing a split optical means having a reflecting polarization plane inclined to the laser radiation light and a split optical means having a reflecting polarization plane faced to this reflecting polarization plane and inclined to the reflected light to make the reflection efficiency of the radiation light constant. CONSTITUTION:The first and second beam splitters 1, 2 have the same characteristics, and the first beam splitter 1 is inserted at the incidence angle theta1 of 45 deg. to the radiation optical path OP or the radiation light LI. The radiation light LI from a laser transmitter 14 is divided into the sample light LS and the radiation light LO by the first beam splitter 1, part of the radiation light LI is reflected by 90 deg. on the reflecting polarization plane 6 of the first beam splitter 1 into the sample light LS, and the remaining portion is transmitted through the reflecting polarization plane 6 into the radiation light LO. Reflecting polarization planes 6, 5 of the first and second beam splitters 1, 2 are arranged at positions rotated by 90 deg., and the sample light LS is reflected on the reflecting polarization plane 5 into the sample light LSO.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser treatment apparatus having a function of monitoring the intensity of irradiation light.

[0002]

2. Description of the Related Art In a laser treatment apparatus, for example, a YAG laser photocoagulation surgical apparatus, one beam splitter is inserted in the irradiation optical path of laser light. A general method is to monitor the intensity of irradiation light by sampling part of the laser light (irradiation light) reflected or transmitted by this one beam splitter.

[0003]

In the irradiation light intensity monitor according to the conventional method as described above, when the irradiation light is randomly polarized, the reflectance and the transmittance change depending on the polarization direction, and the irradiation light intensity is accurately measured. Is impossible to monitor. Particularly, in the case of an uncoated beam splitter, the difference in reflectance between P-polarized light and S-polarized light is remarkable. By coating the beam splitter, it is possible to reduce the difference in reflectance depending on the polarization direction.
Accurate monitoring of changing random polarization is not possible because it is not possible to have a perfect 1: 1 ratio of polarizations.

It is an object of the present invention to provide a laser treatment apparatus capable of sampling randomly polarized irradiation light easily and accurately without applying a special coating.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a first splitting optical means having a first reflection polarization plane inclined with respect to a laser irradiation light from a laser oscillation means at a predetermined angle, and a first reflection polarization plane. And a second splitting optical unit having a second reflecting polarization plane facing each other and arranged at a predetermined angle with respect to the reflected light from the first splitting optical unit, regardless of the deflection component of the reflection efficiency of the laser irradiation light. The gist is a laser treatment apparatus characterized by including an optical system configured to be constant.

According to the present invention, the first splitting optical means is disposed so that its first reflection polarization plane is inclined with respect to the laser irradiation light from the laser oscillation means, and the second reflection polarization plane opposite to the first reflection polarization plane. Second split optical means having a surface and provided so as to be inclined at a predetermined angle with respect to the first reflected light from the first split optical means, and arranged to reflect the second reflected light in a direction forming a constant angle with the laser irradiation light. The gist of the laser treatment apparatus is that it is provided with an optical system configured to make the reflection efficiency of the laser irradiation light constant regardless of its polarization component.

Preferably, the first splitting optical means is arranged at a 45 ° angle with respect to the laser irradiation light, and the second splitting optical means is arranged at a 45 ° tilt with respect to the reflected light from the first splitting optical means. It is a laser treatment device characterized by. More preferably, the laser treatment apparatus is characterized in that the second dividing means is arranged so as to reflect the second reflected light in a direction perpendicular to the laser irradiation light.

[0008]

With the first splitting optical means and the second splitting optical means,
The ratio of P-polarized light and S-polarized light of laser irradiation light (sample light) is set to 1: 1. Thus, even if the laser irradiation light is randomly polarized, the laser irradiation light is sampled regardless of the change in the polarization direction.

[0009]

FIG. 1 shows an ophthalmic YAG laser photocoagulation surgical apparatus which is a preferred embodiment of the laser treatment apparatus of the present invention.

The YAG laser photocoagulation surgical apparatus has a main body 10
And a probe 12. The main body 10 and the probe 12 are connected by an optical fiber 16. A Q switch pulse YAG laser oscillator 14 and an optical system 20 are arranged in the main body 10. Laser irradiation light (hereinafter referred to as irradiation light) LI emitted from the laser oscillator 14 passes through the optical system 20 and serves as laser irradiation light (hereinafter referred to as irradiation light) LO as the optical fiber 1.
It is guided to 6. The irradiation light LO passes through the optical fiber 16,
The probe 12 irradiates the treatment area of the eye.

On the other hand, the irradiation light LI is separated into intensity measuring sample light LSO in the optical system 20 and is incident on the intensity measuring meter 22. The intensity of the sample light LSO is measured by the intensity measuring meter 22.

The optical system 20 has the structure shown in FIG. The optical system 20 has a first beam splitter 1 and a second beam splitter 2. The first beam splitter 1 and the second beam splitter 2 have the same characteristics and do not require any special coating. The first beam splitter 1 has an incident angle θ with respect to the irradiation light path OP or the irradiation light L1 as shown in FIG.
1 is inserted at 45 °. The irradiation light LI from the laser oscillator 14 is split into the sample light LS and the irradiation light LO by the first beam splitter 1. That is, the irradiation light LI
Is partially reflected by the reflective polarization plane 6 of the first beam splitter 1
The sample light LS is reflected as reflected light at an angle of °, and the remaining portion of the irradiation light LI is transmitted to the reflection polarization plane 5 of the first beam splitter 1 to become irradiation light LO.

The second beam splitter 2 receives the sample light L
The S is reflected so that the incident angle θ2 is 45 ° in the polarization direction rotated by 90 ° with respect to the polarization direction reflected by the first beam splitter 1. In other words, the first
The reflection polarization plane 6 of the beam splitter 1 and the reflection polarization plane 5 of the second beam splitter 2 are arranged at positions rotated by 90 °. The sample light LS is reflected by the reflective polarization plane 5 to become the sample light LSO.

By combining the first beam splitter 1 and the second beam splitter 2, one P-polarized light beam and one S-polarized light beam are obtained.
Since the reflectance difference of the polarized light is canceled, even if the irradiation light LI is randomly polarized light, accurate sampling and monitoring can be performed regardless of the change of the polarization direction.

Therefore, the first beam splitter 1 and the second beam splitter 1
The beam splitter 2 does not need to be particularly coated to make the reflectances of P-polarized light and S-polarized light equal, and can be used without coating. Moreover, it is only necessary to combine a total of two first beam splitters 1 and second beam splitters 2 having the same characteristics.

In FIG. 2, irradiation light LI, sample light LS,
The X and Y directions of the polarization components of the sample light LSO are indicated by arrows. When the X and Y directions of the irradiation light LI and the X and Y directions of the sample light LSO are compared, they are rotated by 90 °. Sample light LSO is irradiation light LI
And a right angle.

The polarization component of the irradiation light LI will be separated in the X and Y directions. When uncoated plates are used for the first and second beam splitters 1 and 2, the difference in reflectance depending on the polarization direction has the characteristic shown in FIG. FIG. 3 shows the incident angle θ1,
The relationship between θ2 and reflectance is shown. Curve (a) in FIG.
Represents the reflectance in the vertical direction. This reflectance indicates the Y component (P polarized light). The curve (b) in FIG. 3 represents the reflectance in the parallel direction. This reflectance indicates the X component (S polarized light). When the irradiation light LI is incident on the first beam splitter 1 at an incident angle θ1 of 45 °, the X component is S polarized light and the Y component is P polarized light.
It becomes polarized light, and its reflectance is 9% for S-polarized light, as shown by the value of the curve (a) in FIG. 3 when the incident angle θ1 is 45 °.
P-polarized light is 2% as shown by the value of the curve (b).

In the second beam splitter 2, conversely, the X component is P polarized light, the Y component is S polarized light, and the reflectance is shown by the value of the curve (a) in FIG. 3 when the incident angle θ2 is 45 °. Thus, P polarization is 2% and S polarization is 9% as represented by curve (b). That is, after being reflected by the two first and second beam splitters 1 and 2, both the X component and the Y component become equal to 0.18%. That is, the ratio of the sample light amounts of P-polarized light and S-polarized light can be made completely 1: 1.

Now, assume that the polarization component of the irradiation light changes extremely. The case of irradiation light of X component 100% and Y component 0% is compared with the case of irradiation light of X component 0% and Y component 100%. In the case of one beam splitter, the sample light amounts are 9% and 2%, respectively, and even when the incident light amount is the same, the sample light amounts from the respective irradiation lights differ by 4.5 times. However, according to the configuration of the present invention, a constant sample light amount of 0.18% can always be obtained by the intensity measuring meter 22 of FIG. 1 regardless of the change of the polarization component if the incident light amount is the same.

By the way, the present invention is not limited to the above-mentioned embodiments, but the present invention can be applied to other laser treatment apparatus of the YAG laser photocoagulation surgical apparatus for ophthalmology and other laser processing apparatus.

[0021]

According to the present invention, the laser irradiation light having the random polarization characteristic can be sampled easily and accurately without applying a special coating. Therefore, the laser irradiation light can be obtained with an accurate laser irradiation light intensity.

[Brief description of drawings]

FIG. 1 is a view showing a YAG laser photocoagulation surgical apparatus for ophthalmology, which is a preferred embodiment of the laser treatment apparatus of the present invention.

FIG. 2 is a perspective view showing a sampling optical system of an ophthalmic YAG laser photocoagulation surgical apparatus which is a preferred embodiment of the laser treatment apparatus of the present invention.

FIG. 3 is a diagram showing a relationship between an incident angle and reflectance in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st beam splitter (1st division | segmentation optical means) 2 2nd beam splitter (2nd division | segmentation optical means) 5 Reflection polarization plane (2nd reflection polarization plane) 6 Reflection polarization plane (1st reflection polarization plane) 10 Main body 14 Laser Oscillator 20 Optical system 22 Output measurement meter LI irradiation light (laser irradiation light) LO irradiation light (laser irradiation light) LS sample light LSO sample light ◆

Claims (4)

[Claims] 1. A first splitting optical means arranged with its first reflection polarization plane tilted at a predetermined angle with respect to the laser irradiation light from the laser oscillation means, and a second reflection polarization plane facing the first reflection polarization plane. And a second split optical means arranged to be tilted at a predetermined angle with respect to the reflected light from the first split optical means, and configured to make the reflection efficiency of the laser irradiation light constant regardless of its deflection component. A laser treatment apparatus having a system. 2. A first splitting optical means having a first reflection polarization plane inclined with respect to a laser irradiation light from the laser oscillation means at a predetermined angle, and a second reflection polarization plane facing the first reflection polarization plane. Second split optical means which is provided to be inclined with respect to the first reflected light from the first split optical means by a predetermined angle and is arranged to reflect the second reflected light in a direction forming a constant angle with the laser irradiation light. And a laser treatment apparatus comprising an optical system configured to make the reflection efficiency of laser irradiation light constant regardless of its polarization component. 3. The laser treatment apparatus according to claim 1 or 2, wherein the first splitting optical means is set to 4 for the laser irradiation light.
A laser treatment apparatus characterized in that it is arranged at an angle of 5 ° and the second dividing optical means is arranged at an angle of 45 ° with respect to the reflected light from the first dividing optical means. 4. The laser treatment apparatus according to claim 1, wherein the second splitting optical means is arranged so as to reflect the second reflected light in a direction perpendicular to the laser irradiation light. Laser treatment device characterized by.