JPS61111790A - Optical path switching device for laser imprinting device - Google Patents

Abstract

PURPOSE:To execute easily switching and to reduce the cost of equipment by constituting a device by combining a polarizing element and a liquid crystal light bulb. CONSTITUTION:Transparent conductive electrodes 11, 21 and liquid crystal molecule oriented layers 12, 22 are provided on one surface of transparent conductive glass substrates 1, 2, respectively. Subsequently, on the other surface, reflection preventive films 13, 23 are provided. Also, a space between spacers 3 is sealed with a twist nematic liquid crystal material 4, and a liquid crystal light bulb is constituted. When an AC electric field of several volts is applied to the electrodes 11, 21, a YAG laser beam 100 is switched to an S polarized light 101 or a P polarized light 102, and by a polarizing element 5, the S and P polarized lights are switched to optical paths 103, 104, respectively. By incorporating this device constituted with the liquid crystal light bulb and the polarizing element 5, into a laser imprinting device, the optical path can be switched easily with a good reproducibility, and also the cost of equipment of the device can be reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical path switching device for a laser processing device, and particularly to an optical path switching device for switching a wide beam width laser beam of a laser marking device into a plurality of optical paths. It is related to the device.

A laser marking device transmits a laser beam emitted from a laser light source through a mask having an opening.

An aperture image is formed on the sample by an imaging lens.

This is a device that stamps by burning out or changing the quality of the laser beam irradiation part. Normally, there is one marking optical system consisting of this mask and an imaging lens, but in order to improve the marking efficiency or in a process that requires marking of a plurality of classifications, it is necessary to use a plurality of marking optical systems.

[Conventional technology]

Conventionally, two systems of 9th order have been considered as optical path switching means for these marking optical systems.

■ A method that mechanically switches the optical path using a rotating mirror or galvanometer.

■ A method that uses a laser light source that emits a linearly polarized YAG laser beam, and combines an electro-optic crystal and a polarizing element to guide the laser beam to different optical paths.

[Problem that the invention seeks to solve]

However, since the laser marking speed is as fast as about 10 marks per second, it is difficult to obtain a good switching speed and optical path reproducibility with the method (2). In addition, since the beam width of the laser beam is usually 5 crn or more at the mask surface, the method (2) requires a large electro-optic crystal, making the device expensive.

Furthermore, the method (2) requires the application of a high electric field to drive the electro-optic crystal, and has the disadvantage that the crystal itself is easily damaged by laser beam irradiation.

An object of the present invention is to provide an inexpensive optical path switching device for a laser marking device that can switch a laser beam with a large beam width at high speed and with good optical path reproducibility, can be driven with a low electric field, and has little optical damage. .

[Means for solving problems]

The optical path switching device for a laser marking device of the present invention includes a laser light source that emits a linearly polarized YAG laser beam.

In a laser marking device having at least two or more sets of marking optical systems each consisting of a mask having an open pattern and an imaging lens, the marking optical system [function] and the liquid crystal light valve are configured to include, as will be described in detail later, Generally, 2
It has a structure in which an alignment treatment layer is provided on two transparent conductive electrode glass plates, and a liquid crystal material is sandwiched between the two transparent conductive electrode glass plates with a spacer interposed therebetween. With this structure, depending on whether or not an alternating current electric field is applied between the two electrodes, the linearly polarized light incident on the liquid crystal light bulb can be switched into two linearly polarized lights that are perpendicular to each other.

The liquid crystal light valve is driven by applying an alternating current electric field of several volts to two transparent conductive electrode glasses, and changing the electric field strength.

It can be switched from 10-2 seconds to 3×10 seconds.

Therefore, high-speed switching that can sufficiently correspond to the marking speed of the laser marking device is possible.

Furthermore, by increasing the number of combinations of liquid crystal light valves and polarizing elements, it is possible to easily switch between a plurality of optical paths. Additionally, because the structure of the liquid crystal light valve is simple, large ones can be manufactured easily and at low cost.

Easily handles switching of laser beams with wide beam widths. Furthermore, since liquid crystal is a type of electro-optic material, there is no need to use moving parts, and the reproducibility of the optical path when switching the optical path is extremely excellent. moreover.

Since liquid crystals are inexpensive elements, even if a liquid crystal light valve suffers light damage, it can be easily replaced.

〔Example〕

Hereinafter, two embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of an optical path switching device for a laser marking device according to the present invention.

In FIG. 1, reference numerals 1 and 2 are transparent conductive glass substrates on which transparent conductive electrodes 11 and 21 are provided.
However, antireflection films 13 and 23 for laser beams are provided on the other glass surfaces, respectively. Spacers 3 are provided around the periphery between the two transparent conductive glass substrates 1 and 20, and a twisted nematic liquid crystal material 4 is sealed in the space narrowed between them. These two transparent conductive glass substrates 1, 2. The spacer 3 and the twisted nematic liquid crystal material 4 constitute a liquid crystal light valve.

An alternating electric field of several volts is applied to the two transparent conductive electrodes 11.21, and the presence or absence of this electric field is dependent on the presence or absence of this electric field.

A linearly polarized laser beam (
Assume that this is S polarized light) 100.

It can be switched to S-polarized light 101 or P-polarized light 102. The S-polarized light 101 emitted from the liquid crystal light valve is sent to the optical path 103 by the polarizing element 5, and the P-polarized light 102 is sent to the optical path 1.
04, and the optical path can be switched depending on the presence or absence of an electric field.

FIG. 2 is a diagram showing an example of a laser marking device when the optical path switching device shown in FIG. 1 is applied to a sorting process. In this example, the sorting process is divided into four processes, A, B, C, and D. In each laser marking process, a mark (tA71° (L B II , tl
Mask 30 with an open pattern of CII and 'D'
, 31, 32 and 33 are provided.

Imaging lenses 40°41 corresponding to each mask,
4.2 and 43 are installed, stamp position 50°51.52
and 53 are irradiated with a laser beam.

An optical path switching device 60°61,62 consisting of a liquid crystal light valve and a polarizing element and a reflecting mirror 63 are provided in each optical path so that each optical path can be switched and irradiated.

In such a configuration, the incident linearly polarized laser beam 200 is introduced into the optical path 70 when the optical path switching device 60 is on, and 13. when the optical path switching device 60 is off. It is connected to the optical path 80 of C and D. Similarly, when the other optical path switching devices are off, a laser beam is introduced into the selected optical path with the optical path switching device on, and the sorting can be marked with a laser.

〔Effect of the invention〕

According to one aspect of the present invention, as is clear from the above description.

An optical path switching device capable of switching the optical path of a laser beam having a wide beam width with good reproducibility can be provided at a low cost, and there are advantages in that a plurality of optical paths can be easily switched.

Remaining days below

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of an embodiment of the optical path switching device for a laser marking device according to the present invention, and FIG. 1 is a diagram showing an example of a laser marking device. 1.2...Transparent conductive glass substrate, 11.21...
Transparent conductive electrode, 12.22...Liquid crystal molecule alignment layer. 13.23...Anti-reflection film, 3...Spacer, 4...
... Twisted nematic liquid crystal material, 5... Polarizing element.

Claims (1)

[Claims] 1. In a laser marking device comprising a laser light source that emits a linearly polarized YAG laser beam and at least two sets of marking optical systems each consisting of a mask having an aperture pattern and an imaging lens, the optical path of the marking optical system An optical path switching device for a laser marking device, characterized in that the switching device is a combination of a polarizing element and a liquid crystal light valve.