JPH01215290A - Laser processing - Google Patents

Abstract

PURPOSE:To enable samples such as cells to be processed in an arbitrarily desired depth, by vibrating the condenser lens for laser beam in the axial direction, when they are processed by irradiating with laser beam. CONSTITUTION:When a sample such as cells are processed by irradiating it with a laser beam condensed with a lens, the lens is vibrated in the direction of the optical axis to reciprocate the focus, and simultaneously the stage holding the sample is allowed to move or the laser beam incident to the objective lens is polarized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for processing a raw sample by irradiating a raw sample such as a living cell such as an egg or a microorganism with a laser beam.

[Conventional technology]

Details of a conventional living cell laser perforation device are described in Japanese Patent Publication No. 7837/1983, and the vicinity of the objective lens of this device is shown in FIG.

The laser is focused at its narrowest point at the focal plane of A, and forms a curve before and after that.For samples 3, such as living cells, the processed area may be perforated at the focal plane, or for very thin samples, the laser may not be irradiated. The stage on which the sample was placed was moved while the sample was being cut.

[Problem to be solved by the invention]

The above-mentioned conventional technology is mainly based on the perforation function for transferring DNA and the like into living cells, and sufficient consideration has not been given to the cutting function. Therefore, as shown in Figure 2, if the thickness of the sample was sufficiently thin compared to the depth of focus of the beam that could be processed, it was possible to cut the sample, but the diameter was 10μ.
This was not possible for samples with a spherical shape of approximately 200 m in diameter, such as fertilized eggs.

Therefore, when cutting such a thick sample, manually move the stage up and down (Z direction) as shown in Figure 3.
It was necessary to move the sample in the Z direction and simultaneously move it in the cutting direction (X direction).

The objective lens of this device has two functions: the function of focusing the laser and the function of a microscope to obtain an enlarged image of the sample, and the microscope function is lost when the stage is moved in the Z direction as described above. Therefore, the cutting operation is performed without being able to grasp the condition of the sample. Therefore, when using live samples such as fertilized eggs, the method often causes excessive damage to the sample, causing the sample to die and often failing. In addition, manual operation of moving the stage required a great deal of effort.

SUMMARY OF THE INVENTION An object of the present invention is to provide a laser processing method that facilitates the cutting operation and allows the cutting operation to be performed while grasping the cutting situation using an enlarged image of a microscope.

[Means to solve the problem]

The above purpose is to vibrate the lens constituting the beam expander in the optical axis direction to reciprocate the focal point of the laser focused by the objective lens in the optical axis direction, and at the same time move the stage that protects the sample. This is achieved by deflecting the optical axis of the laser beam that enters the objective lens.

[Effect]

When the lens constituting the beam expander is vibrated in the optical axis direction, the focal point of the laser focused by the objective lens moves back and forth in the optical axis direction. In this state, when the stage holding the sample is moved within the plane of the stage, the sample is processed into a linear shape with a thickness that approximates the moving distance of the focal point in the optical axis direction.

Further, by deflecting the optical axis of the laser beam incident on the objective lens by moving the stage within the plane, the focus can be moved within the plane of the stage and processing along the same line as above can be performed. In all of the above methods, the distance between the sample and the objective lens is constant, so the processing status of the sample can be observed, and compared to conventional techniques.

Processing effort is significantly reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1 and FIGS. 4 to 7.

FIG. 1 is a diagram showing the overall configuration, in which a laser 10 adjusts its beam with an optical interface 11, and then a microscope 8
The objective lens 1
The direction in which the light enters the object is controlled and the light enters the objective lens. The laser incident on the objective lens is narrowed down and irradiated onto the sample 3 fixed on the stage 6 to process the sample. The microscope has a TV camera 16 that observes the sample image, and a contour detector 17 that compares and detects the axial part of the sample and the laser irradiation point.
K has been used. A stage controller 7 is also installed to control the stage within the plane of the stage (XY force direction and vertical direction (two directions)).

The optical interface 11 includes a beam expander 1 that controls the position of the focal point of the laser focused by the objective lens.
2 is included, and furthermore, a lens vibrating device that vibrates the lens 13 that constitutes this beam expander in the optical axis direction! 14 and a lens vibration controller 15 for controlling the vibration of this lens.

Next, a detailed explanation of the 12 beam expanders will be given using FIG.

In Figure 4, the two lenses on the left constitute the beam expander, and the one on the right is the objective lens.As the lenses of the beam expander in Figure 0 move in the optical axis direction, the focus of the beam focused by the objective lens is as shown in Figure 4. An example of the movement distance Ω of the lens and the movement distance Δ of the focal point is shown in FIG. 5.

Therefore, by utilizing this behavior, the distance between the sample and the objective lens is constant, that is, the sample can be cut while viewing an enlarged image of the sample.

Hereinafter, the operation of the present invention will be explained using FIG. 1 and FIGS. 5 to 7.

When cutting the sample starts, the lens vibration controller 15
Then, the lens of the beam expander starts reciprocating motion by a predetermined distance (for example, Ql in FIG. 5) in the optical axis direction by the lens excitation device 14, and thereby the focus of the beam focused by the objective lens also moves in the optical axis direction. It moves by ΔQx in FIG. 5 at the same period as the lens movement described above.

In this state, when stage 6 is moved in the X direction, the sample is cut as shown in Figure 6.The thickness of the sample is Δ
When it is thinner than a, cutting ends when it reaches the end of the sample (point A in Figure 6).

On the other hand, when the thickness of the sample is thicker than ΔΩ, the edge of the sample is detected by the contour detector 17, the signal is input to the stage controller 7, and the stage moves to a predetermined position as shown in FIG. Increases by distance. Thereafter, the stage moves in the opposite direction in the x7 direction, and the sample is cut by repeating zero or more operations to continue cutting. At this time, the position of the focal point of the enlarged image of the microscope shifts when the stage rises, but this position means that a new cut plane will be observed.
The same plane is then observed until the stage is raised.

The ease with which a sample is cut depends on the physical properties of the sample, but if the sample is difficult to cut, this can be dealt with by controlling the moving speed of the lens, the moving speed of the stage, etc.

In other words, FIG. 7 shows a cross section of a sample when a PAL laser is used as laser 10. If the laser irradiation points are indicated by circles, the spacing of the irradiation points in the Z direction is equal to the distance between the lenses of the beam expander 12. Depends on travel speed and laser pulse repetition frequency.

Further, the interval between the irradiation points in the X direction depends on the moving speed of the stage in the X direction.

Therefore, as shown in 18 in Figure 1, 1
By controlling the lens vibration controller 5, the stage controller 7, the pulse repetition frequency of the laser 10, etc., the sample can be cut under optimal conditions.

The method of moving the stage during cutting has been described above, but if the thickness of the sample is thinner than Δa in FIG. This can also be handled by changing the angle (in the XY plane). Furthermore, if the sample is thicker than ΔQ, a combination of an optical path deflector and a stage may be considered.

C. Effects of the invention] According to the present invention, even if the sample is thick, the distance between the processed surface of the sample and the objective lens can be kept constant, so the processing status can be observed with a microscope, and the processing effort can be significantly reduced. can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIGS. 2 and 3 are front views of the vicinity of the objective lens of the prior art, and FIGS. 4 and 5 are explanatory diagrams of the behavior of the beam expander. FIG. 6 is a detailed diagram of one embodiment of the present invention. FIG. 7 is a sectional view of the sample at the time of cutting, which is the I-1 section in FIG. 6. DESCRIPTION OF SYMBOLS 1... Objective lens, 6... Stage, 7... Stage controller, 9... Optical path deflection device, 12...
Beam expander, 14... Lens excitation device, 15
...Lens excitation controller, 16...TV camera, 17...Contour detector.

Claims (1)

[Claims] 1. In a laser processing method in which a lens is used to focus laser light and the sample is irradiated with the laser light to process the sample, the lens is vibrated in the optical axis direction. By moving the focal point of the laser focused by the lens back and forth in the optical axis direction and moving the stage holding the sample, or by deflecting the optical axis of the laser beam incident on the objective lens, the sample is heated to a predetermined thickness. A laser processing method characterized by linear processing.