JPS60236483A - Laser heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a laser heating device that processes a workpiece by irradiating a laser beam to the workpiece, and particularly relates to a laser heating device that has a uniform energy density distribution suitable for heat treatment processing. The present invention relates to a laser heating device that can irradiate a workpiece with a laser beam.

[Prior art]

Usually, the energy density of a laser beam extracted from a Leb oscillator has various distributions depending on the characteristics of the oscillator. Taking the case of Gaussian TgMoo as an example, as shown in (1) in Figure 1, the laser beam has a high energy density at the center, and the energy density □ degree becomes an exponential function as you move from the center to @i'E. It is declining. When a workpiece is irradiated with such a laser beam (1) and scanned, the heating temperature of the scanning center axis is extremely high, and it is difficult to heat it to a uniform temperature. As a method of changing the energy density distribution of the beam and the shape of the laser beam, for example, a method as disclosed in Japanese Patent Publication No. 58-3478 has already been proposed. In this method, a laser beam taken out from a laser oscillator is divided into a plurality of parts, and the divided plurality of parts are divided so that the energy density distribution of the laser beam is almost uniform in at least one direction on the irradiation surface of the workpiece. The high energy density and low energy density parts of each laser beam are superimposed and combined to irradiate the workpiece.In these four methods, the laser beam is scanned in a certain direction. In the case,
Although it has the feature of being able to heat to a uniform temperature, it has the disadvantage that it cannot heat to a uniform temperature when the scanning direction changes.

[Summary of the invention]

The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and includes a polarizing means 9 for shifting the irradiation position of the laser beam onto the workpiece by a predetermined distance from the original irradiation position, and also It is an object of the present invention to provide a laser heating device that can make the energy density distribution of the laser beam uniform by having a configuration in which the laser beam is rotated about the incident axis of the laser beam.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser heating device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view showing the entire laser heating device.

In the figure, (2) is the energy density QtM that is emitted from a laser oscillator (not shown) and has a Gaussian beam cross section.
f7sv-zabi, -lens that focuses light on the beam (1), (3
) is a flat rotating mirror that polarizes the laser beam (1) approximately 900 degrees, and is fixed to a rotating cylinder (4) coaxially arranged with the laser beam incident axis (1a). The rotating cylinder (4) is supported by a bracket (7) via bearings (5) and (6), and a gear (8) formed at the top is a gear αQ driven by an electric motor (9).
It is configured to be rotatable around the laser beam incident axis (1 m) as a rotating shelf. (II) is a ring mirror that is supported by a bracket (7) via a holder (on a holder) and has a shade-shaped reflective surface on its inner surface, and reflects the laser beam incident from the rotating mirror (3) to the workpiece ( 2) Irradiate the specified position. The rotating mirror (3) and the ring midge (b) constitute a polarizing means α◆, and this polarizing means α→ allows the center position of the irradiation range of the laser beam on the workpiece (to) to return to the original point. Point (B) after polarization from (4)
By rotating the rotating mirror (3) in the direction of the arrow (g), the irradiation range is spread over a circle whose radius is the distance between the point prisoner and point (B), with the point (4) as the center. will be moved.

That is, as shown in FIG. 3, which explains the rotation of this laser beam, the laser beam (1) with Gaussian distribution is
It is rotated around the a-axis, and it is important to set the rotation speed appropriately, and the appearance is as shown in Figure 4 above.
An energy density distribution close to the donut-shaped laser beam α· of MOI is obtained. The energy density distribution shown in Figure 4 is low in the center, but the cumulative amount of laser beam irradiation time on the workpiece* (to) is high in the center, so the workpiece (2) absorbs the energy. The energy density distribution is almost uniform, and a uniform temperature distribution can be obtained in any direction.

The distance (up to) by which the laser beam is shifted by the polarizing means q4 is determined based on the diameter of the irradiation surface of the laser beam on the workpiece 0, taking into consideration the form of the energy density distribution of the laser beam and the specifications of the workpiece Sakaki. Select an appropriate value within the following range.

In the above embodiment, a case has been described in which the laser beam (1) is focused to heat the workpiece (to), but there is a case where the laser beam (1) does not need to be focused. , the same effect can be obtained even if the lens (2) is removed. Further, in the above embodiment, the lens (2) is used as a means for condensing the laser beam (1), but a concave mirror may be used to condense the laser beam (1), or the lens (2) may not be used.
A similar effect can be obtained by using the rotating mirror (3) or the ring mirror Q1 as a concave mirror to focus the light.

Furthermore, in the above embodiment, the polarizing means 4 is composed of a rotating mirror (3) and a ring mirror αη, but as shown in FIG. The laser beam incident axis (1a) is arranged in a staggered manner.
The lens may be rotated around f = mechanical lens α.

〔Effect of the invention〕

As explained above, the present invention has a configuration in which polarization means is provided to shift the irradiation position of the laser beam onto the workpiece by a predetermined distance from the original irradiation position, and the polarization means is rotated about the laser beam incident axis. Therefore, there is an effect that the energy density distribution absorbed by the workpiece becomes uniform and the temperature distribution becomes uniform.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the energy density distribution of a laser beam having a Gaussian energy density distribution, FIG. 2 is a sectional view showing the entire laser heating device according to an embodiment of the present invention, and FIG. FIG. 4 is a perspective view showing the energy density distribution of the laser beam obtained by the device shown in FIG. 2. FIG. It is a block diagram which shows the principal part of a V-za heating apparatus. In the figure, (1) and (1. are laser beams, (1
&) is the laser beam incident axis, □□□ is the workpiece, q→,
a71 is a polarizing means. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa

Claims (4)

[Claims] (1) In a device that heats a workpiece by irradiating a laser beam emitted from a laser oscillator to the workpiece, the laser beam is disposed on the axis of the laser beam between the laser oscillator and the workpiece. A laser heating device characterized in that a polarizing means is provided for shifting the irradiation position on the workpiece by a predetermined distance from the original irradiation position, and the polarizing means is rotated about the laser beam incident axis. (2) The laser according to claim 1, wherein the predetermined distance by which the irradiation position of the laser beam is shifted by the polarizing means is set to be less than or equal to the diameter of the irradiation surface of the workpiece with the laser beam. heating device. (3) The polarizing means includes a rotating mirror that reflects the laser beam from the laser oscillator, polarizes it by approximately 90 degrees, and is configured to be rotatable around the laser beam incident axis, and the laser beam reflected by this rotating mirror is provided on the inner surface. 3. The laser heating device according to claim 1, further comprising a ring mirror that reflects the light from a cap-shaped reflecting surface and irradiates the workpiece at a predetermined position. (4) Claim 1, characterized in that the polarizing means is a lens arranged such that its central axis is shifted by a predetermined angle from the laser beam incidence axis and configured to be rotatable about the laser beam incidence axis. The laser heating device according to item 1 or item 2.