JPH0539466Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an integrating sphere type laser power sensor that measures the output of a laser oscillator.

[Prior Art] FIG. 3 is a configuration diagram showing an example of a conventional integrating sphere type laser power sensor that measures the output of a laser oscillator. 1 is a water-cooled integrating sphere with a double structure whose spherical surface is plated with gold so that the laser beam is diffusely reflected.
Reference numeral 2 designates a laser beam input port through which the monitoring laser light L enters from the direction of the arrow, and reference numeral 3 designates a laser beam output port from which minute laser light attenuated within the spherical surface of the integrating sphere 1 is taken out. Further, 4 is a laser power sensor having a small heat capacity, small size, and capable of high-speed response for measuring attenuated minute laser light, 5 is an inlet/outlet of water cooling water, and 5a is a cooling water channel.

Next, the operation will be explained. A monitoring laser beam L output from a laser oscillator enters an integrating sphere 1 from a beam entrance 2. The incident laser beam is repeatedly reflected diffusely inside the integrating sphere 1, is made uniform, and is attenuated in proportion to the inner area of the integrating sphere 1. At this time, water is passed through the cooling water channel 5a provided around the integrating sphere 1 from the water-cooled water inlet/outlet 5 to cool the integrating sphere 1 and remove the influence of heat. The laser light that has been homogenized and attenuated within the integrating sphere 1 is taken out from the beam output port 3, inputted into a laser power sensor 4 that measures minute laser output, and converted into an electrical signal.

[Problems to be solved by the invention] According to the conventional integrating sphere type laser power sensor 4 configured as described above, when the output or beam diameter of the monitoring laser beam L incident in the direction of the arrow increases. In order to keep the input power within the allowable input range of the laser power sensor 4, the attenuation rate must be increased by attenuating the incident power at the front stage of the integrating sphere 1 or increasing the diameter of the integrating sphere 1. For this, it is necessary to reduce the beam diameter using a condensing lens (mirror) in accordance with the incident diameter of the integrating sphere 1, and the equipment for this becomes complicated, and there are problems such as an increase in space and an increase in cost. It was hot.

This invention was made to solve the above problems, and even when the output of the monitoring laser light increases or the beam diameter increases,
The purpose of this invention is to obtain an integrating sphere type laser power sensor that can measure the output of a laser oscillator using the same integrating sphere and laser power sensor.

[Means for Solving the Problems] The present invention has been made to achieve the above object, and is provided at the entrance of the monitoring laser beam of the integrating sphere, and from the entrance side of the monitoring laser beam. A funnel-shaped passage whose diameter decreases toward the exit side, a condensing lens provided at the entrance of this passage, and a corner protruding inward near the exit of the passage corresponding to the base of the funnel mouth. An integrating sphere type laser power sensor equipped with a laser beam converter and an inner limiter for laser beam attenuation that is formed and collides with the laser beam incident from the entrance, absorbs a part of it, limits its progress, and attenuates the laser beam. It provides:

[Operation] A monitor laser beam with a high output and a large beam diameter has its input attenuated or its beam diameter reduced by a beam converter, enters an integrating sphere, and then reaches a laser power sensor, where the laser oscillator is Output is measured.

[Embodiment of the invention] FIGS. 1 and 2 are a configuration diagram showing an embodiment of the invention and a sectional view showing an enlarged main part (dotted chain line portion) thereof. Note that the same or corresponding parts as in the conventional example shown in FIG. 5 are given the same reference numerals, and the explanation thereof will be omitted.
6 is directed from the entrance side to the exit side of the beam entrance 2 of the integrating sphere 1 so as to attenuate the laser output or reduce the beam diameter in response to changes in the incident power and beam diameter of the monitoring laser beam LL. It is a beam converter that has a funnel-shaped passage that narrows in diameter.

Reference numeral 7 denotes an inner limiter for attenuating laser light (hereinafter simply referred to as an inner limiter). This inner restriction portion 7 is
A corner portion corresponding to the base of the mouth of the funnel is formed protruding inward near the exit of the passage of the beam converter 6, and collides with the laser light incident from the entrance of the passage, absorbing a portion of the laser beam and restricting its progress. , which attenuates it. In addition, 8 is the laser beam LL for monitoring.
In order to reduce the beam diameter, a condensing lens (mirror) is provided at the tip of the beam converter 6, that is, at the entrance of the funnel-shaped passage.

The operation of the present invention configured as above will be explained as follows. A monitoring laser beam LL [diameter D] having a large output and a large beam diameter outputted from a laser oscillator is incident through a condensing lens 8 attached to the tip of the beam converter 6 . After that, the monitor laser beam LL with high output and large beam diameter was used.
The light is condensed and reduced in diameter by the condenser lens 8, becomes a monitoring laser beam, and collides with the inner limiter 7 of the beam converter 6, where a portion is absorbed, its progress is restricted, and it is attenuated. In this case, the laser beam LM that hits the inner limit portion 7 of the beam converter 6 and is absorbed therein is heat absorbed by water cooling because the beam converter 6 is integrated with the integrating sphere 1.
Next, this monitoring laser beam LM enters the integrating sphere 1 through the beam entrance 2a, and is thereafter converted into an electric signal by the laser power sensor 4 in the same manner as described in FIG. Note that d indicates the beam diameter of the conventional monitoring laser beam L explained in FIG.

[Effects of the invention] As is clear from the above description, according to the invention, the laser beam is provided at the entrance of the monitoring laser beam of the integrating sphere, and is contracted from the input side of the monitoring laser beam toward the exit side. a funnel-shaped passageway with a diameter;
A condensing lens installed at the entrance of this passage and a corner part protruding inward near the exit of the passage corresponding to the base of the mouth of the funnel collides with the laser light incident from the entrance and absorbs a part of it. Since it is equipped with a laser beam converter equipped with an inner limiter for laser light attenuation that limits the progress and attenuates, it can respond to a wide range of changes in laser output and beam diameter using the same integrating sphere and laser power sensor. This has the effect that the device can be made small and inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a sectional view enlarging the main part of Fig. 1, and Fig. 3 is a block diagram showing an example of a conventional integrating sphere type laser power sensor. . 1... Integrating sphere, 2a... Beam entrance, 3...
Beam output port, 4... Laser power sensor, 5...
... Water cooling water inlet/outlet, 6... Beam converter, 7...
Inner limiter, 8...Condensing lens, LL...Laser beam for monitoring. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] In an integrating sphere type laser power sensor that attenuates incident monitoring laser light using an integrating sphere whose interior is gold-plated and measures the output of the attenuated minute laser light, A funnel-shaped passage provided at the entrance of the monitoring laser beam of the integrating sphere and whose diameter decreases from the input side to the exit side of the monitoring laser beam, and a passage provided at the entrance of the passage. A corner portion corresponding to the base of the mouth of the funnel is formed protruding inward near the exit of the condensing lens and the passage, and collides with the laser light incident from the entrance;
An integrating sphere type laser power sensor comprising a laser beam converter having an inner limiter for attenuating laser light that absorbs a portion of the laser beam, limits its progress, and attenuates the laser beam.