JPH0833521B2 - Light irradiation device - Google Patents

Description

The present invention relates to a light irradiation device.

[Outline of Invention]

According to the present invention, in the light irradiation device, by having an optical system composed of four lenses and three prisms, it is possible to obtain two rectangular beams in a desired rectangular shape from one incident beam. It is the one.

[Conventional technology]

Light, such as laser light, is generated by the flat package IC (FPI
It is used as energy for melting solder when soldering electronic components such as C). In many cases, the electronic parts to be laser-processed have a rectangular (rectangular) shape to be processed, and it is necessary to make a laser beam having a circular basic beam rectangular.

Conventionally, as a means for converting this laser light into two rectangular beams, there is a mask plate 32 having a rectangular opening 33 as shown in FIG. 7, and a circular laser beam 31 has an opening.
Two rectangular beams 34 are formed on the substrate 30 through 33.
In addition, first, the laser beam made parallel by the collimator lens is transformed into an elliptical beam by the concave cylindrical lens, and then made into a parallel elliptical beam by the convex cylindrical lens,
A light irradiation device has been proposed in which two beams are formed by a half mirror and a total reflection mirror, and each beam is passed through two triangular prisms to form two rectangular beams. (Japanese Patent Application No. 61-224559) [Problems to be Solved by the Invention] In the case of the above-mentioned mask plate, in order to change the respective dimensions G, H, I of the rectangular shape of the beam, the respective dimensions of the rectangular opening are changed. There are methods such as changing or changing the mask plate, but a complicated mechanism is necessary to adjust the respective dimensions G, H, and I of the rectangular shape independently of each other. further,
Since a part of the circular basic beam is used to form a rectangular beam, the energy loss is large and the energy density of the rectangular beam is non-uniform.

The light irradiation device that forms a rectangular beam using two triangular prisms has high energy efficiency of the rectangular beam,
Moreover, the energy density is uniform, but since the half mirror is used to create the two rectangular beams, the spectral precision cannot be adjusted, and the distance from the light source to the two rectangular beams is not equal. The disadvantages are the inability to focus on the beam and the lack of versatility due to the fixed shape of the rectangular beam.

[Means for solving problems]

Means for solving the above problems will be described below with reference to FIG. 1 corresponding to the embodiment.

The present invention is a light irradiation device for forming two rectangular beams, including: (a) a collimator lens 12 for obtaining a first parallel beam 12 ', (b), the first parallel beam 12'. Is converted into a beam 14 that diffuses only in one direction, a first concave cylindrical lens 13, (c), a convex cylindrical lens 15 that converts the diffused beam 14 into a second parallel beam 15 ', (d), the second parallel beam A first triangular prism 17 that divides 15 ′ into two spectral beams 18, (e), a second triangular prism 19 that adjusts the interval between the two spectral beams 18, (f), and a light beam that passes through the second triangular prism 19. The second concave cylindrical lens 22 and (g) that diffuse the formed beam 21 only in the longitudinal direction of the rectangular shape, and the beam 23 that has passed through the second concave cylindrical lens 22 is divided into two in the longitudinal direction of the rectangular shape and then superimposed on each other. Rectangle Third triangular prism forming beam 27
24 are linearly and sequentially arranged on the optical axis, and the convex cylindrical lens 15, the second triangular prism 19 and the third
The present invention relates to a light irradiation device configured so that the triangular prism 24 can move on the optical axis.

〔Example〕

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

As shown in FIG. 1, the light irradiation device of the present embodiment is such that a collimator lens 12, a laser beam 11 emitted from an optical fiber 10 connected to a laser oscillator (not shown) are linearly and sequentially arranged on the optical axis. The optical system includes a first concave cylindrical lens 13, a convex cylindrical lens 15, a first triangular prism 17, a second triangular prism 19, a second concave cylindrical lens 22 and a third triangular prism 24.

The convex cylindrical lens 15 has a first direction in which light changes.
They are arranged in the same direction as the concave cylindrical lens 13. The first triangular prism 17 is arranged at a position where the ridge is on the upper side and serves as the beam center.
19 is arranged so that the ridge is on the lower side and is parallel to the ridge of the first triangular prism 17. The second concave cylindrical lens 22 is arranged at an angle in which the light changing direction is orthogonal to the case of the convex cylindrical lens 15. Third triangular prism
24 has a ridge on the lower side and the second concave cylindrical lens 22
Are arranged so as to be parallel to the bus line of.

The convex cylindrical lens 15, the second triangular prism 19 and the third triangular prism 24 are arranged in parallel with the optical axis by arrows 16 and 2, respectively.
It is possible to move along 0 and 25.

According to the light irradiation device of this embodiment, two rectangular beams 27 are formed as follows.

The laser beam 11 emitted from the optical fiber 10 has a circular shape and the energy density thereof is generally Gaussian. The beam 11 becomes a parallel circular beam 12 'by the collimator lens 12, and the first concave cylindrical lens 13
As a result, an elliptical beam 14 is formed which spreads in only one direction at right angles to the output axis. This beam 14 becomes a parallel elliptical beam 15 'by the convex cylindrical lens 15 and is incident on the first triangular prism 17. Since the prism 17 is arranged so that the short axis of the parallel elliptical beam 15 ′ and the ridge of the prism 17 coincide with each other, the parallel elliptical beam 15 ′ is first divided into half of the ellipse along its short axis. It is split into two spectral beams 18 having a shape. Then, each of these two beams 18 emerges from the prism 17 at an angle that intersects the other beam 18 in the major axis direction of the parallel elliptical beam 15 '. The beam 18 then passes through a second triangular prism 19, which corrects the two angled beams 18 in said prism 17 to opposite angles. The beam 21 that has passed through the prism 19 becomes a beam 23 that is diffused only in the direction corresponding to the longitudinal direction of the rectangular shape by the second concave cylindrical lens 22, and then enters the third triangular prism 24. Since the prism 24 is arranged so that the ridge of the prism 24 passes through the center in the side direction of the straight line in the beam 23 having the shape of one half of the ellipse, one beam 23 is first measured in the side direction of the straight line. At the center position of the beam is split into two beams 26 having the shape of a quarter of an ellipse. Each of these two beams 26 is the other beam in the side direction of the straight line of the beam 23.
The light exits from the prism 24 at an angle where it overlaps with 26. 1
Two beams 26 split from one beam 23 are prisms
As the distance from 24 increases, the overlapping ratio increases, so that the straight sides of the two beams 26 having the shape of a quarter of an ellipse become the three sides of the rectangle, that is, the overlapping ratio becomes close to the maximum. The rectangular beam 27 is obtained at the point where the energy density in the longitudinal direction of the rectangle becomes substantially uniform.

The convex cylindrical lens 15 adjusts the focus of the rectangular beam 27 and moves along the arrow 16 to adjust the width dimension K of the rectangular beam 27. Second triangular prism 19
Adjusts the distance L between the rectangular beams 27 by moving along the arrow 20. The third triangular prism 24 adjusts the lengthwise dimension J of the rectangular beam 27 by moving along the arrow 25.

Next, the FPIC 1 is mounted on the substrate 5 shown in FIG.
An example of forming the short-sided rectangular beam 3 and the long-sided rectangular beam 4 necessary for soldering via the light irradiation device of this embodiment will be described with reference to FIGS.

Adjustment of Rectangular Beam Interval: The intervals F and C of the rectangular beams 3, 3 and 4, 4 in FIG. 2 are adjusted by the movement of the second triangular prism 19 in FIG. Beam 18 split by the first triangular prism 17
Travel in a direction intersecting with each other and enter the second triangular prism 19. The prism 19 bends the beam 18 in the opposite direction at an angle smaller than or equal to the angle bent by the first triangular prism 17,
It is emitted as a beam 21. The spacing between beams 21 is prism 19
It changes by changing the position of, and finally the interval of the rectangular beams also changes. That is, the beam interval can be changed from C to F by moving the prism 19 of FIG. 3 to the position of the prism 19 of FIG. 4 by a distance of M.

Adjustment in the length direction of the rectangular beam: To adjust the lengths D and A of the rectangular beams 3 and 4 in FIG. 2, the third triangular prism 24 in FIG. 5 is adjusted in the optical axis direction (arrow 25 in FIG. 1). Direction). The prism 24 is the second
The width of the synthetic beam 26 is changed depending on the light receiving position of the beam 23 diffused by the concave cylindrical lens 22.

In order to change the rectangular beam length from D in FIG. 5 to A in FIG. 6, the prism 24 in FIG. 5 is replaced by the prism 24 in FIG.
Move N to the position.

Adjustment in the width direction of the rectangular beam: The respective widths E and B of the rectangular beams 3 and 4 in FIG. 2 are the convex cylindrical lens 15 and the first concave cylindrical lens 13.
Since the image forming position changes depending on the interval between and, the divergence angle of the beam 26 in the width direction also changes.

Adjustment of Energy Density: In FIGS. 5 and 6, the beam 26 divided and synthesized from the center by the third triangular prism 24 advances while changing the overlapping rate according to the distance from the prism 24.
The energy density required for processing must be uniform over the section of the lengths D and A of the rectangular beam, and when a beam having a Gaussian distribution is used for the beam 11, the overlap ratio is almost at the maximum. A rectangular beam with a uniform energy density is obtained. P in FIG. 5 and Q in FIG. 6 represent points of uniform energy density in rectangular beams of different sizes, which can be obtained by adjusting the distance from the entire optical system.

〔The invention's effect〕

As described above, the following effects can be obtained by the light irradiation device of the present invention: (1) Two rectangular beams can be obtained from one incident beam, and the rectangular beams can change the beam interval and the rectangular shape. It became possible and generalized.
(2) Since the two rectangular beams have the same optical conditions, the precision is good, and the spectral precision is the first triangular prism 17
The position can be adjusted. (3) The energy density in the longitudinal direction of the rectangular beam is uniform because the beams are divided into two by the third triangular prism 24 and then overlapped with each other, and the overlapping ratio can be adjusted. (4) In forming a rectangular beam, all the incident beams are taken into the lens system and processed only by transmission, so that the energy efficiency is high.
(5) The cost is low because lenses and prisms having complicated shapes are not used. (6) The arrangement of the lens system is linear, so that the accuracy is high and the reliability is high.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a light irradiation device of the present invention,
FIG. 2 is a perspective view showing the FPIC and the substrate, FIGS. 3 and 4 are side views of the optical system of the embodiment, and FIGS. 5 and 6 are front views of the optical system of the embodiment. , FIG. 7 is a perspective view of a conventional example. In the reference numerals used in the drawings, 11 ... Laser beam 12 ... Collimator lens 13 ... First concave cylindrical lens 15 ... Convex cylindrical lens 17 ... First triangular prism 19 ... Second triangular prism 22. 2 concave cylindrical lens 24 …… third triangular prism 27 ………… It is a rectangular beam.

Claims (1)

[Claims] 1. A light irradiation device for forming two rectangular beams, comprising: (a) a collimator lens for obtaining a first parallel beam; (b) a first parallel beam in one direction. (C) a convex cylindrical lens that converts the diverging beam into a second parallel beam; (d) a first concave cylindrical lens that divides the second parallel beam into two spectral beams (1) a triangular prism, (e), a second triangular prism for adjusting the distance between the two spectral beams, (f), a second concave cylindrical lens for diffusing the beam transmitted through the second triangular prism only in the longitudinal direction of the rectangular shape And (g), a third triangular prism for forming a rectangular beam by dividing the beam, which has passed through the second concave cylindrical lens, into two in the longitudinal direction of the rectangular shape, and superposing them on each other. A light irradiating device configured such that the lenses are arranged linearly and sequentially on the optical axis, and the convex cylindrical lens, the second triangular prism, and the third triangular prism are movable on the optical axis.