JPH01321082A - Laser beam marking device - Google Patents

Abstract

PURPOSE:To improve workability of a laser beam marking by moving the position of an image formation lens of the title laser beam making device and changing an image formation ratio without moving a mask and the focusing position. CONSTITUTION:A beam shaping optical system, the mask 1 and an image formation optical system 5 are arranged successively at prescribed intervals on a laser beam optical axis. At this time, the image formation optical system 5 is constituted by combining two concave and convex lenses 5a and 5b and as necessary, the composite focal length is changed from f' to f'' by moving the lenses 5a and 5b. By this method, the composite focal length f' s changed only by moving the positions of the lenses 5a and 5b and the size D of an image at a fixed image formation point 3 is changed freely and the image formation ratio is changed. Since the operation of the device is simplified only by moving the lenses, the workability of marking is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Field of Application)] The present invention relates to a laser marking device, and particularly to an improvement in its imaging lens system.

(Prior Art) Conventionally, a laser marking device is configured as shown in FIG. is shaped to have an appropriate cross-sectional shape. This shaped laser beam 4 is irradiated onto the mask 1. This mask 1 has, for example, a pattern to be marked formed with a portion that transmits the laser beam 4 and a portion that blocks the laser beam 4.

The laser light that has passed through the mask 1 is irradiated onto an imaging point (workpiece) 3 through an imaging lens 2 made up of one or more assembled lenses.

At this time, since the pattern formed on the mask 1 is focused on the imaging point 3 by the imaging lens 2, the pattern of the mask 1 is marked on the workpiece.

By the way, when changing the marking size, if the imaging ratio is constant, the mask 1 is replaced, and if the imaging ratio is changed to change the marking size, then the mask 1 is replaced as shown in Fig. 3. a (distance between mask and imaging lens),
Mark the workpiece according to the following relational expression (2) of b (distance between the imaging lens and the imaging position) and the focal length f of the imaging lens 2, determine the size, and determine the size of the pattern on the mask 1. The imaging magnification is determined from Therefore, relational expression (1)
, (2), the values of a and b are calculated, and the distance to the workpiece is set.

a/b-imaging magnification...(1)1/
f −1/a + 1/b −= (2
) However, f: focal length of the imaging lens (problem to be solved by the invention) In the conventional laser marking device described above, although it is inexpensive, it attempts to change the mark size on the workpiece with the same mask pattern. In this case, the focal position of the workpiece must be kept constant, and the mask 1 and the imaging lens 2 must be moved and fixed at two locations, making the work complicated.

This invention can change the imaging ratio of the mask pattern, that is, the size of the pattern to be marked on the workpiece, without changing the imaging position of the mask pattern, and has significantly improved workability. The purpose of the present invention is to provide a laser marking device.

[Structure of the Invention] (Means for Solving the Problems) This invention provides a method for converting laser light emitted from a laser oscillator into
In a laser marking device that marks the pattern of the mask on the workpiece by irradiating the workpiece through at least a lens, a mask, and an imaging lens, the imaging ratio can be adjusted by moving only the imaging lens. This is a laser marking device that is characterized by the ability to

(Function) According to the present invention, by moving the lens based on the combination of concave and convex portions in the imaging optical system, it is possible to change the size of the marking pattern on the surface of the workpiece without changing or moving the mask. The focus on the surface of the workpiece does not change.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The laser marking device according to the present invention is constructed as shown in FIG. 1, and the same parts as in the conventional example (FIG. 3) are given the same reference numerals.

That is, on the optical axis of laser light emitted from a laser oscillator (not shown), a beam shaping optical system (not shown), a mask, and an imaging optical system 5 are sequentially arranged at predetermined intervals. There is.

In this case, the imaging optical system 5 has two concave and convex imaging lenses 5 a
As shown in FIG. 2, the combined focal length can be changed from f' to f' by moving the imaging lenses 5a and 5b as necessary. The magnification a/b is changed.

In the case of the inter-lens distance C shown in FIG. 1, the combined focal length f' is the following, where the focal length fI of the concave imaging lens 5a and the focal length f2 of the convex imaging lens 5b are Determined from the formula.

1/f'=1/f1+1/f
2 C/f1 ・f2 ... (3) Also in Fig. 2, when the distance between the lenses becomes C', the formula (
By substituting C' into 3), the composite focal pressure i! fi f
' is calculated. The size of the image at the imaging point 3 changes to D and D' according to the calculated composite focal length f',
Different imaging ratios can be obtained while the distance a'+b from the mask 1 to the imaging point 3 remains constant without moving the imaging point 3 at that time.

[Effects of the Invention] As explained above, according to the present invention, since the imaging optical system is composed of a plurality of imaging lenses, the focal length can be changed by changing the distance between the lenses of the imaging optical system. Can be changed. As a result, by moving the plurality of imaging lenses without moving the mask and the focal point position, it is possible to obtain the imaging point, that is, the size of the mask pattern on the workpiece.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a laser marking device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing a case where the imaging ratio is changed in the laser marking device of the present invention, and FIG. FIG. 1 is a schematic configuration diagram showing a conventional laser marking device. 1... Mask, 3... Imaging point (workpiece), 5...
- Imaging optical system, 5a, 5b...imaging lens. Applicant's agent Patent attorney Takehiko Suzue Figure 3

Claims (1)

[Claims] A laser marking device that marks a pattern of the mask on a workpiece by irradiating the workpiece with laser light emitted from a laser oscillator through at least a lens, a mask, and an imaging lens. A laser marking device characterized in that the imaging ratio is changed by moving only the imaging lens.