JPH03180285A - Laser beam printing machine - Google Patents

Abstract

PURPOSE:To carry out printing with high accuracy by arranging an X-Y scanner, a laser beam shaping convex lens, a transmission diffusion type liquid crystal mask, a condensing convex lens and a printing objective lens on a laser beam optical path getting to a workpiece from a laser beam oscillator. CONSTITUTION:A laser beam from the laser beam oscillator 1 is made incident on a rotary polygonal mirror 3 and reflected with the width in the X-Y direction and made incident on a cylindrical concave lens 4. The whole surface area of the transmission diffusion type liquid crystal mask 6 is then irradiated with the laser beam via the laser beam shaping convex lens 5. Optional characters and figures are formed by a controller on the transmission diffusion type liquid crystal mask 6. The laser beam transmitted through parts corresponding to these characters and figure are corrected on size and aberration by the condensing convex lens 7 and the printing objective lens 8 and then, image-formed and these characters and figures are marked on the marking surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser printing device that stamps characters or figures on a marking surface using laser light.

[Prior Art] Conventionally, the following laser printing devices are known.

(1) Laser light is applied directly and spot-wise to the mask surface made of metal or glass! 1. A product that evaporates the concave material and engraves letters and figures on it.

(2) Two mirrors are manipulated vertically and horizontally using a galvano scanner, etc., and the laser beam is controlled to form letters and figures, thereby stamping letters and figures on the stamping surface.

(3) Using a polarizing plate and an IR1 product, characters and figures such as (f) are formed on this liquid crystal, contrast is imparted to the laser beam, and these characters and figures are engraved on the engraved surface.

[Problems to be Solved by the Invention] However, the above conventional laser printing apparatus has the following problems. That is, (1) in the metal or glass mask method, the laser beam is directed Qq QJ directly onto the mask surface, so that it is not possible to arbitrarily engrave characters or figures. Furthermore, even if a method is adopted in which characters and figures on the mask are selected and engraved using a mirror, the types of characters and figures that can be made are limited.

(2) In the method in which two mirrors are operated by a galvano scanner, if an arbitrary character or figure is to be engraved, the control system for vertical and horizontal operation of the galvano scanner becomes complicated. Furthermore, since the laser beam oscillator used in the printing device has relatively large energy, is large in size, and is expensive, the hardware and software become large-scale.

(3) In the method using a polarizing plate and liquid crystal, a transmittance loss of 30 to 40% occurs in the polarizing plate, resulting in a decrease in printing power. Therefore, it is necessary to increase the size of the laser beam oscillator by the amount of loss power. As a result, the entire device becomes larger and more expensive. Moreover, when increasing the size, the output laser beam oscillator must be limited to a large output laser beam oscillator that does not damage the liquid crystal mask. Furthermore, in controlling the liquid crystal, it is complicated to adjust the timing of afterimages during scanning.

The present invention has focused on the above-mentioned conventional problems, and an object of the present invention is to provide a laser printing device that can easily and accurately engrave arbitrary characters and figures using a small-capacity laser beam oscillator.

[Means for Solving the Problems] In order to achieve the above object, a laser printing device according to the present invention includes a laser beam oscillator, an X-Y scanner that scans a laser beam in the vertical and horizontal directions on a transmission scattering type liquid crystal mask. , a convex lens for laser beam shaping, a transmission scattering liquid crystal mask, a convex condensing lens, and an objective lens for printing.

Further, in a laser printing device equipped with a laser beam oscillator, a polygon mirror scanner and a mirror scanner or a cylindrical concave lens as means for scanning the laser beam emitted from the laser beam oscillator onto a transmission-scattering type liquid crystal mask surface, a polygon mirror scanner is used. The configuration includes a means for detecting the rotational position and a means for controlling the position of the mirror scanner or the cylindrical concave lens using the detection signal. It has a circuit that detects at least two or more objects within an angle, opens a laser shutter with a detection signal of at least one of them, and closes the laser shutter with at least one remaining detection signal, and a laser is attached to the edge of the polygon mirror. Light may not be irradiated.

Furthermore, the scanning angle on the transmission scattering type liquid crystal mask surface may be made to substantially match the angle formed by two detection positions 4J within the rotation angle of one polygon mirror.

[Operation The laser light oscillated from the laser light oscillator is scanned in the vertical and horizontal directions by an X-Y scanner and irradiated onto the entire area of the transmission scattering type liquid crystal mask. The laser light that has passed through the parts corresponding to the characters and figures formed on this transmission-scattering liquid crystal mask is repeatedly irradiated onto the workpiece through a convex condensing lens and an objective lens for printing, and these characters are printed on the engraved surface. or engrave shapes. In a transmission-scattering type liquid crystal mask, the laser light is scattered in areas where characters or figures are not formed, that is, areas through which the laser light does not pass, so that no shadow is cast on the workpiece.

When using a polygon mirror scanner and a cylindrical concave lens or carbano mirror scanner as an X-Y scanner, the following problems will occur unless these are controlled reliably.

(1) YAG laser (wavelength 1064 rlm)
), it is effective to use a polygon mirror coated with a dielectric multilayer film in order to obtain a high reflectance, but if the laser beam is applied to the edges of the polygon mirror, it is effective. , damage to the dielectric multilayer film is likely to occur. Furthermore, if the laser beam hits the edge portion of the mirror, the laser beam will be scattered, which is unfavorable from a safety standpoint.

(2) To solve the above problem, the laser beam was changed to 0N10F.
It is possible to do F. However, ON10 of laser light
Since there is a delay time in F F, if you try to make the scanning speed (polygon mirror rotation speed) variable, a complicated delay circuit and arithmetic circuit will be required, making the device larger and more expensive. .

Therefore, a means for detecting the rotational position of the polygon mirror scanner (for example, if a DC pulse motor with an encoder is used, the rotational position can be detected by the signal from the encoder) is provided, and the signal detection position is set at each surface of the polygon mirror. A point that coincides with the polygon mirror scan angle (in this case the X-axis scan angle), or a point that is slightly larger (
There are 2 points on each side).

Using the detection signals from these two points, the laser beam can be adjusted to 0N10.
By controlling the FF and the Y-axis scanner mirror, accurate and safe scanning can be performed without the need for a delay circuit or an arithmetic circuit.

In the above case, position detection may be performed using a slit plate synchronized with the mirror edge instead of the encoder.

[Example] The following is an example of the laser printing device according to the present invention.
A detailed description will be given with reference to the drawings.

In FIG. 1, a polygon mirror scanner 3,
A cylindrical concave lens 4, a laser beam shaping convex lens 5, a transmission scattering type liquid crystal mask 6, a condensing convex lens 7, and a printing lens 8 are provided.

As shown in FIG. 2, the polygon mirror scanner 3 has 7.
A plurality of mirrors are provided in the shape of a polygon (10 square in the embodiment) on a 50 Orpm motor shaft. Therefore, the laser beam entering the rotating polygon mirror is reflected with a width in the XX direction in FIG. Since the cylindrical concave lens 4 is rotated around the X axis by a driving device, the laser beam transmitted through this cylindrical concave lens 4 has a width in the Y-Y direction, and the laser beam passes through the cylindrical concave lens 4 and the polygon mirror scanner 3 and the cylindrical concave lens 4. Therefore, the area is controlled in the X-Y direction. Then, the laser beam passes through a convex lens 5 for shaping the laser beam and illuminates the entire area of the transmission scattering type liquid crystal mask 6. Letters and figures are formed on the transmission-scattering type liquid crystal mask 6 by a control device (not shown), and the laser light that has passed through the portions corresponding to these letters and figures is sent to the condensing convex lens 7 and the printing convex lens 7. The size and aberration are corrected and an image is formed by the objective lens 8, and these characters and figures are engraved on the engraved surface.

In the transmission-scattering type liquid crystal mask 6, the laser beam is scattered in areas where characters or figures are not formed, that is, areas through which the laser beam does not pass, and does not affect the gossamer workpiece 2. Note that by controlling the voltage applied to the electrodes of the transmission-scattering type liquid crystal mask 6, the laser light transmittance can be adjusted and the marking depth etc. can also be controlled.

FIG. 3 is a diagram showing a second embodiment of the present invention, in which the cylindrical concave lens 4 in FIG. 1 is replaced with a galvano mirror.
A scanner 9 is provided, and the laser reflected light in the X-X direction by the polygon mirror scanner 2 is reflected in the Y-Y direction using the galvanometer mirror scanner 9, and the laser beam is passed through a convex lens for shaping the laser beam 5 to a transmission scattering type liquid crystal display. The configuration is such that the entire area of the mask 6 is exposed to the ejaculation. The laser light that has passed through the part of the transmission-scattering liquid crystal mask 6 that corresponds to the characters and figures is condensed by the condensing convex lens 7, further passes through the printing objective lens 8, reaches the marking surface of the workpiece 2, and the marking surface to engrave characters and shapes on.

FIG. 4 is a diagram showing a third embodiment of the present invention, in which a hologram scanner lO is used instead of a polygon mirror scanner and a cylindrical concave lens or carbano mirror scanner.
It is a k thing that has been installed. The laser beam is reflected in the X-Y direction by the hologram scanner 10, passes through the convex lens 5 for laser beam shaping, and is applied to the entire area of the transmission scattering type liquid crystal mask 6. The laser light that has passed through the parts of the transmission-scattering type liquid crystal mask 6 corresponding to the characters and figures enters the condensing convex lens 7. The light is then condensed and further passes through the printing array lens 8 to reach the stamping surface of the workpiece 2, where characters and figures are stamped on the stamping surface.

FIG. 5 is a diagram showing a fourth embodiment of the present invention, in which the convex convex lens 7 for condensing and the array lens 8 for printing in FIG. Install it and
The structure is such that the laser beam transmitted through the transmission scattering type liquid crystal mask 6 is directly irradiated onto the marking surface of the workpiece 2. Such a configuration may be used depending on the size of the stamped surface of the workpiece.

6 to 9 are diagrams for explaining a control method when scanning a transmission scattering type liquid crystal mask surface using a polygon mirror scanner and a mirror scanner such as a cylindrical concave lens or a galvano mirror scanner. In FIG. 6, if the number of mirror surfaces of the polygon mirror scanner 3 is n, then l C+ OC2 (i.e. α+θ+α=θ+2α
) is 360″/n=θ+2α.Here, θ is the scanning angle in the X-axis direction on the liquid crystal mask surface.In other words, θ out of one surface θ+2α of the polygon mirror is used for scanning.Polygon mirror rotation position is detected at the position corresponding to this θ minute, that is, al, a2+ a3+aa
, ・・・・・・A2n will be used. FIG. 6 shows an example of a six-sided polygon mirror, in which case at, a2.・◆◆・・at2(as～a
Position detection is performed at 12 locations (12 not shown). The rotational position can be easily detected by, for example, driving a DC pulse motor and adding an encoder to it as shown in FIGS. 7 and 8.

In FIG. 9, when the laser beam reaches position al, the laser shutter is opened (O
N), the X-axis scan is started. When the polygon mirror scanner rotates θ and the laser beam comes to position a2,
The laser shutter is closed (OFF) by the detection signal,
Stop commercial use of laser light. When a2 is detected, a laser shutter OFF command and a drive command for the Y-axis scanner mirror are issued.

The Y-axis scanner mirror is driven and positioned to the next predetermined scan line setting position, and preparation for the next X-axis scan is completed.

This Y-axis drive is set to be completed from a2 to a3. In other words, the number of rotations of the polygon mirror is N
If it is rps, then the Y-axis drive is tyku2α/36ON
It is set to seconds. Therefore, as the drive source for the Y-axis, a motor with a high speed startup or a galvano type motor is suitable.

When the Y-axis drive is finished and the position a3 is reached, the laser shutter is opened again and X-axis scanning is performed.

Since the laser beam is blocked at positions a2 and a3,
The laser beam is not irradiated to the 02 part (the edge part of the polygon mirror), and the dielectric multilayer film may be destroyed, the laser light hitting the edge part may be scattered, causing damage to surrounding equipment, or causing damage to the human body (especially This can prevent accidents such as accidental irradiation of the eyes (eyes) and blindness.

0N10FF of the laser beam needs to be performed at high speed, and when a YAG laser is used as the laser beam, an acousto-optic Q switch element (AOQ switch), a galvano type shutter mirror, etc. can be used.

Although there is a slight delay in the shuttering time of the laser beam (within several hundred μs if the above method is used), the position actually irradiated with the laser beam is slightly shifted from a to a2 due to this delay. This deviation poses no problem as long as the shuttering delay is only slight. In other words, the positional shift is △
If β, the irradiation to the polygon mirror is a1+△β~a
2+Δβ, and the scanning angle θ is constant. However, the X-axis scan start position and end position on the mask surface will shift, but the position must be adjusted in advance to account for the shift, or the mask scan surface can be moved within an angle slightly smaller than the scan angle θ. Make sure it fits,
There's no problem.

Next, details of embodiments of claims (2) and (3) will be described with reference to FIG.

1) Laser; YAG laser, wavelength 1.06 μm, A
With OQ switch, oscillation frequency 3 RHZ, beam diameter φ
2 2) Polygon mirror; 12 sides (30°/plane) 1 side 30
Two detection positions were provided: al at 3° from the edge and a2 at 27°.

The scanning angle is 27'-3°=246.

3) Polygon mirror drive source: DC pulse motor, position detection was performed using an encoder.

4) Polygon mirror rotation speed; 246/20m5=3.
333rps=20Orpm 5) Y-axis scanner drive source: DC pulse motor, positioning time 3m5 (positioning time required for 0, 36° rotation) 6) Liquid crystal mask: scattering type liquid crystal mask, pattern part size 70x70rnm 7) Laser shutter Ring; Laser shutter link is implemented using a Q-switch with a built-in laser. When scanning the liquid crystal mask surface with the above specifications, the X-axis laser pulses were 60 pulses/70 rn m, and the Y-axis was 43 pulses/70 mm (that is, the X-axis 43 lines), and the total scanning time is 25
m5×43=1.075 seconds.

0N10FF of the laser beam was performed using a Q switch element. The delay time was approximately 0.6 ms. This corresponds to about 2 laser pulses. This shift could be easily corrected by slightly shifting the polygon mirror rotation detection positions al and a2. Since the edge portion of the polygon mirror was not irradiated with laser light, no problem occurred. The Y-axis positioning time is 3 ms, and the laser beam O
From FF to ON (i.e. from a2 to a3) is 5
xn s, positioning will be completed before the next X-axis scan begins, and it was confirmed that accurate scanning can be performed.

In this way, in this embodiment, a high-speed scanner such as a cylindrical mirror scanner, a cylindrical concave lens scanner, a Calhano mirror scanner, or a hologram scanner is used to irradiate the transmission scattering type liquid crystal mask with laser light. Four laser beams are applied to the entire area of the transmission scattering type liquid crystal mask several hundred times for 7 minutes. Even if a certain figure is formed on a transmission-scattering type liquid crystal mask for only one second, even if the figure is carved in half, each laser irradiation can be performed about 10 times, so-called overlapping strikes.

Furthermore, since the transmission scattering type liquid crystal mask does not use a polarizing plate or a polarizing mirror, there is no decrease in transmittance.

Therefore, even a laser beam oscillator with a small output can be used efficiently.

The arrangement order of the polygon mirror scanner and the cylindrical concave lens scanner or the galvano mirror scanner may be arbitrary. Alternatively, a configuration may be adopted in which two polygon mirror scanners are used to scan in the vertical and horizontal directions.

In addition, the rotational position of the polygon mirror scanner is detected and the laser beam irradiation is controlled by 0N10FF, and the position of the mirror scanner for Y-axis scanning is controlled accordingly, so X-Y scanning can be performed with high precision. , and can be done safely.

[Effects of the Invention] As explained above, according to the present invention, a polygon mirror scanner, a cylindrical concave lens, and a galvano mirror are installed on the laser light path from the laser beam oscillator to the marking surface of the workpiece.
By arranging a scanner and a hologram scanner in an appropriate combination, the laser beam is scanned onto a transmission scattering type liquid crystal mask, and is projected onto the workpiece using a convex condensing lens and an objective lens for printing. , it is possible to perform overprinting by high-speed scanning, and there is no transmission loss due to polarization, so laser energy can be projected efficiently using a small-capacity laser beam oscillator and high-precision printing can be performed. In addition, the convex convex lens for condensing light and the engraving lens for printing provided on the back of the liquid crystal mask make it easy to adjust the size of characters and figures.Moreover, this printing device is small and does not require a large installation space. .

Furthermore, the rotational position of the polygon mirror scanner for X-axis scanning used as a means for scanning the laser beam on the liquid crystal mask surface is detected, and the f, %p, QJ of the laser beam is turned on/off.
As soon as the FF control is performed, the position of the mirror scanner for Y-axis scanning is controlled in response, so that the X-
Y-scanning can be performed accurately and safely, and the quality of laser characters and work efficiency can greatly improve safety.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a 1-system laser printing device according to the first embodiment, Fig. 2 is an explanatory diagram of a 71 Terrigon mirror scanner, and Fig. 3 is a schematic diagram of a laser printing device according to the second embodiment. Diagram,
FIG. 4 is a schematic configuration diagram of a laser printing device according to the third example, FIG. 5 is a schematic configuration diagram of a laser printing device according to the fourth embodiment, and FIG. An explanatory diagram of the light irradiation range, Fig. 7 is a plan view of the polygon mirror scanner equipped with an encoder, Fig. 8 is a sectional view taken along line A-A in Fig. 7, and Fig. 9 is the rotational position of the polygon mirror scanner and its FIG. 10 is a schematic diagram of a laser printing apparatus that performs scanning control based on FIGS. 6 to 9. 1... Laser beam oscillator 3... Polygon mirror scanner 4...
Cylindrical concave lens 5... Convex lens for laser beam shaping 6... Transmissive scattering type liquid crystal mask 7... Convex lens for focusing light 8... Printing lens 9... Carbano mirror scanner 10...
・Hologram scanner

Claims (4)

[Claims] (1) A laser beam oscillator, an X-Y scanner that scans the laser beam in the vertical and horizontal directions on a transmission-scattering liquid crystal mask, a convex lens for shaping the laser beam, a transmission-scattering liquid crystal mask, a convex condensing lens, and printing. A laser printing device characterized by a configuration consisting of an objective lens. (2) In a laser printing device equipped with a laser beam oscillator, a polygon mirror scanner and a mirror scanner or a cylindrical concave lens as means for scanning the laser beam emitted from the laser beam oscillator onto a transmission scattering type liquid crystal mask surface, a polygon mirror 2. The laser printing apparatus according to claim 1, further comprising means for detecting the rotational position of the scanner, and means for controlling the position of the mirror scanner or the cylindrical concave lens based on the detection signal. (3) Detect at least two rotational positions of the polygon mirror scanner within the rotation angle of one surface of the polygon mirror, open the laser shutter with the detection signal of at least one of them, and detect at least one of the remaining ones. 3. The laser printing device according to claim 2, further comprising a circuit for closing the laser shutter in response to a signal, and preventing irradiation of the edge portion of the polygon mirror with laser light. (4) Claim (3) characterized in that the scanning angle on the surface of the transmission-scattering liquid crystal mask substantially matches the angle formed by two detection positions within the rotation angle of one polygon mirror.
Laser printing device described.