JP2000229260A - Direct plotting method and direct plotting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate a zoom mechanism to simplify the device. SOLUTION: A scanning control part 9 moves a laser irradiating part 6 in the K, Y directions, and at this time, a scanning velocity control part 10 of the scanning control part 9 makes variable the scanning velocity of the laser irradiating part 6, that is, the scanning velocity of a laser beam 8 from a laser irradiating port 5, based on the previously set pattern information. In this way, the hardening width of a hardening part of UV ink can be made variable. Therefore, without using a zoom mechanism, adjustment of resolution (DPI) and contrast (LPI) can be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct drawing method and a direct drawing apparatus for drawing a drawing object such as an elevator door panel.

[0002]

2. Description of the Related Art A conventional general technique for drawing a pattern on the surface of a door panel of an elevator cab or a landing is a so-called silk screen method. The silk screen method is to create a silk screen (made of nylon or the like) that has been prepressed so as to leave a mesh in the area where the paint is to be applied, and place the created silk screen on the surface of the door panel to paint. This is a method of printing a desired pattern on the panel surface by extending (ink).

[0003] However, the drawing by the silk screen method cannot improve the resolution more than a certain level due to the limitation of the fineness of the mesh at the time of producing the silk screen. There was a drawback that the position accuracy could not be improved beyond a certain level due to the possibility of expansion and contraction.

Accordingly, the present applicant has recently adopted a method called a direct drawing method as an alternative to the silk screen method. In the direct drawing method, a UV curable ink (UV ink) is applied to a door panel surface in a first step to form a paint layer, and in a second step, the paint layer is irradiated with a laser beam to form the paint layer. This is a method of drawing a desired pattern on the surface of the door panel by curing a part of the door panel and removing an uncured part while leaving a cured part by a washing operation in a third step. The present applicant has already proposed this direct drawing method in Japanese Patent Application No. 10-15784.

FIG. 8 is a perspective view showing the structure of a main part of a direct drawing apparatus used in the direct drawing method. In this figure, a UV ink 2 is applied to a front surface 1a of a panel 1, and a zoom mechanism 3 having a lens system 4 and a motor 5 for performing a zoom drive on the lens system 4 is provided in front of the front surface 1a. Further, a laser irradiation unit 6 having a laser irradiation port 7 is disposed further in front of the zoom mechanism 3.

[0006] The laser irradiation section 6 is mounted on a guide rail (not shown) so as to be movable in the X direction, and the guide rail can be freely moved in the Y direction. That is, the laser irradiation unit 6 and the laser irradiation port 7 can freely move on the XY plane,
It can be moved to a position opposite to an arbitrary point a.

The scanning control section 9 controls the movement of the laser irradiation section 6 and the laser irradiation port 7 to control the scanning of the laser beam 8 emitted from the laser irradiation port 7 with respect to the UV ink 2. The laser irradiation unit 6, the scanning control unit 9, and the zoom mechanism 3 are set in advance with pattern information on a pattern to be drawn, and the scanning control unit 9 performs scanning control based on this pattern information. The irradiation unit 6 controls the irradiation of the laser beam 8 from the laser irradiation port 7, and the zoom mechanism 3 performs zoom control.

Next, the operation of FIG. 8 will be described. The scanning control unit 9 performs scanning control of the laser irradiation unit 6 at a predetermined speed based on the preset pattern information, and the laser irradiation unit 6 controls the irradiation of the laser beam 8 from the laser irradiation port 7. At this time, the zoom mechanism 3 drives the lens system 4 by the motor 5 to perform zoom control, and adjusts the beam diameter of the laser beam applied to the UV ink 2.

In the UV ink 2 applied to the front surface 1a of the panel 1, only the portion irradiated with the laser beam 8 is cured. It can be varied by adjusting the beam diameter. By this variable control of the curing width, the resolution and gradation of the pattern to be drawn are adjusted.
When the irradiation of the laser beam 8 is completed, the panel 1 is conveyed into a cleaning device (not shown) to perform a cleaning operation.
The portion of the UV ink 2 that has not been irradiated with the laser light 8 is an uncured portion, and this uncured portion is removed by a washing operation, and only the cured portion of the UV ink 2 that has been irradiated with the laser light 8 is located on the front surface. 1a. This allows
A desired pattern is drawn on the front surface 1a of the panel 1.

[0010]

However, in the apparatus shown in FIG. 8, the zoom mechanism 3 is used as means for varying the curing width of the cured portion of the UV ink 2, and the structure of the apparatus is complicated. Has become. Such an increase in the complexity of the device configuration increases the possibility of failure,
This is a major factor that complicates maintenance and further hinders cost reduction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a direct drawing method and a direct drawing apparatus which can eliminate the need for a zoom mechanism and can thereby simplify the apparatus. The purpose is.

[0012]

According to a first aspect of the present invention, a photo-curable resin applied to the surface of an object to be drawn is provided on the basis of predetermined pattern information. By irradiating the laser beam to be scanned, by removing the uncured portion of the photocurable resin leaving a cured portion by the laser beam irradiation in the subsequent cleaning work, a desired pattern on the surface of the drawing object In the direct drawing method, a curing width of the cured portion is varied by varying a scanning speed of the laser beam.

According to a second aspect of the present invention, there is provided a photocurable resin which is provided so as to face a drawing object and scan a laser beam along the surface thereof. A direct-writing apparatus comprising: a laser irradiating unit that irradiates a laser beam to the laser beam; and a scanning control unit that controls scanning of the laser beam based on predetermined pattern information. And a scanning speed control means for variably controlling the speed.

According to a third aspect of the present invention, in the second aspect of the present invention, the laser irradiation unit is movable in XY directions along the surface of the object to be drawn, and the scanning speed control means is provided. The scanning speed of the laser beam is variably controlled by controlling the moving speed of the laser irradiation unit.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the laser irradiating unit has mirror means for changing an irradiation angle of a laser beam on a surface of the object to be drawn. The speed control means variably controls the scanning speed of the laser light by controlling the irradiation angle change speed of the mirror means.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. However, the same components as those in FIG. 8 are denoted by the same reference numerals, and redundant description will be omitted. FIG. 1 is a perspective view showing a main configuration of a direct drawing apparatus according to the present embodiment.
FIG. 1 differs from FIG. 8 in that the scanning control unit 9 has the scanning speed control means 10 and the zoom mechanism 3 is omitted. The scanning speed control means 10 variably controls the moving speed when the laser irradiation unit 6 moves in the X direction and the Y direction, that is, the scanning speed of the laser light 8 emitted from the laser irradiation port 7 with respect to the UV ink 2. It has become. Then, the scanning speed control unit 10 performs the above-described variable control of the scanning speed based on the preset pattern information, so that the curing width of the cured portion of the UV ink 2 can be varied. Adjustment of appropriate resolution and gradation can be performed without using the mechanism 3.

Here, the fact that the curing width of the cured portion of the UV ink 2 can be varied by variably controlling the scanning speed of the laser beam 8 will be specifically described using mathematical expressions.

Since the laser beam 8 can be condensed the least when it is in an oscillation state called a so-called single mode, it is usually used in this single mode. FIG. 2 is a characteristic diagram showing an intensity characteristic of the laser beam 8 in the single mode. In this figure, r indicates the radius of the laser beam, I is the optical power per unit area, I0
Indicates the value of I at the center of the beam. As is clear from this figure, the light intensity of the laser beam 8 has a peak value at the center of the beam, and the entire intensity distribution has a Gaussian distribution corresponding to the beam radius. Note that r0 is a radius at which the intensity of the laser beam becomes 1 / e ² (about 13.5%) of the center of the beam, and is called a beam radius.

Assuming that the distribution state of the optical power at a certain point (x, y) on the XY plane is I (x, y), this distribution state I (x, y) is expressed by the following equation (1). . In addition,
In the equation (1), Pt indicates the total power of the laser beam 8, and when the position of the optical axis is represented by (x0, y0), the radius r is represented by the equation (2).

[0020]

(Equation 1) Here, assuming that the beam traveling direction of the laser light 8 is the z direction, the origin of the z axis is set on the irradiation surface of the UV ink 2, and the irradiation direction of the laser light 8 is perpendicular to the irradiation surface. The distribution state I (x, y, z) of the light power in the depth direction of the UV ink 2 is expressed by equation (3) since the light attenuates in the z direction according to the Lambert-Beer law.
Note that Dp in the equation (3) represents the light transmission depth of the UV ink 2.

[0021]

(Equation 2) When irradiating the UV ink 2 with the laser beam 8 stationary, assuming that the exposure time is τ, the exposure amount E (x, y, z) of each portion in the UV ink 2 is expressed by the equation (4). . FIG. 3 shows a cured shape of the UV ink 2 in this case, which has a paraboloid shape as shown.

E (x, y, z) = I (x, y, z) · τ (4) Next, consider a case where the UV ink 2 is irradiated while scanning with the laser beam 8. Scan direction is one axis direction (x axis direction)
And the scanning speed is V, a certain point in the UV ink 2
The light intensity at time t at (x, y, z) is I (x−Vt,
y, z). Then, the scanning range is defined as -∞ <x <
∞, the exposure amount E of each part in the UV ink 2
(x, y, z) is represented by equation (5). Here, E = Ec
Assuming that the curing of the UV ink 2 is started when the (critical exposure amount) is reached, the three-dimensional space in the range of E ≧ Ec, z ≧ 0 becomes a cured shape.

[0023]

(Equation 3) FIG. 4 shows the cured shape of the UV ink 2 in this case. As shown, the z-axis has a parabolic shape, and the x-axis (scanning direction) has a uniform column shape. In general stereolithography for drawing a pattern on a door panel or other cases, laser scanning is performed so that the unit cured shapes overlap as shown in FIG. 3, and the entire cured portion is brought into close contact with each cured portion. It is necessary to form a shape.

The cross section (yz plane) of the cured shape in FIG.
The curing width W is represented by the expression (6) derived from the expression (5), and the curing width W is obtained by substituting z = 0 into the expression (6) to obtain y. ) Expression.

[0025]

(Equation 4) As is apparent from the equation (7), the curing width W is determined by parameters such as the total power Pt of the laser beam 8, the laser beam diameter r0, the scanning speed V, and the critical exposure amount Ec. In some cases, it is difficult to vary parameters other than the scanning speed V. Therefore,
When parameters other than the scanning speed V among these parameters are considered to be constant values, the curing width W can be considered as a function of the scanning speed V, as shown in Expression (8). That is, by variably controlling the scanning speed of the laser beam 8,
The cured width of the cured portion of the V ink 2 can be changed.

W = f (V) (8) FIG. 5 is a characteristic diagram showing the relationship between the curing width W and the scanning speed V. As shown in this figure, the curing width W becomes narrower as the scanning speed V increases, and eventually becomes almost zero.
On the other hand, the curing width W increases as the scanning speed V decreases. However, when the scanning speed V decreases to a constant speed V0, the curing beam W becomes the effective diameter W0 of the laser beam. It does not grow.

FIG. 6 shows the UV when the scanning speed V is varied.
It is sectional drawing which showed the shape of the hardening part 2a and the unhardened part 2b in the ink 2, (a) is a case where a scanning speed is fast,
(B) shows a case where the scanning speed is low. FIG. 6 (a)
In the case where the scanning speed is high as described above, it can be considered that the irradiation time of the laser beam 8 to the UV ink 2 is long,
Therefore, conceptually, the top of the laser light intensity characteristic curve 11 does not sufficiently penetrate into the UV ink 2, and the curing width W1 is narrow corresponding to the width near the top of the laser light intensity characteristic curve 11. On the other hand, when the scanning speed is low as shown in FIG. 6B, it can be considered that the irradiation time of the laser beam 8 with respect to the UV ink 2 is short.
The top of the laser light intensity characteristic curve 11 is sufficiently UV ink 2
And the curing width W2 is the laser light intensity characteristic curve 1
1 is wide corresponding to the width away from the vicinity of the top.

The direct drawing apparatus shown in FIG. 1 is an apparatus for executing a direct drawing method based on the above principle. Next, the operation of FIG. 1 will be described. Scan control unit 9
Moves the laser irradiation unit 6 in the X and Y directions. At this time, the scanning speed control unit 10 of the scanning control unit 9 uses the moving speed of the laser irradiation unit 6, that is, the laser irradiation based on the preset pattern information. The scanning speed of the laser beam 8 from the opening 7 is varied. FIG. 7 is an explanatory diagram showing a change in the curing width corresponding to a change in the scanning speed at this time.

The scanning speed of the laser beam 8 changes according to the scanning speed characteristic curve 12 shown in FIG. 7A, and the beam shape 13 of the laser beam 8 moves in the direction of the arrow in FIG. 7B.
FIG. 7B is a plan view of the application surface of the UV ink 2 as viewed from above.

As shown in FIG. 7A, when the scanning speed is V
In the state of 1, since the laser irradiation time is long, the curing width is set to a relatively large value of W3 as shown in FIG.
It is. However, when the scanning speed is increased from V1 to V2, the laser irradiation time is shortened, so that the curing width becomes W4 smaller than W3.

As described above, when irradiating the UV ink 2 with the laser beam 8, the curing width W of the cured portion 2 a of the UV ink 2 can be varied by varying the scanning speed. Therefore, resolution (DPI) and gradation (LPI) can be adjusted without using a conventional zoom mechanism.

In the above-described embodiment, it is assumed that the laser irradiation unit 6 is moved on the XY plane by a motor drive mechanism or the like (not shown) to scan the laser beam 8. It is also possible to scan the laser beam 8 by the method. For example, the laser irradiation unit 6 is provided with mirror means for reflecting the laser light 8 from the laser irradiation port 7, and the laser light irradiation angle of the mirror means with respect to the front surface 1 a of the panel 1 is variably controlled to thereby control the laser light. 8 may be performed. According to this, it is possible to more quickly control the scanning speed, and it is possible to adjust the resolution and the gradation with higher accuracy.

In the above embodiment, the coating material is UV
Although the example using the ink 2 has been described, the paint may be any photo-curable resin that is cured by light irradiation, and other paints may be used.

Further, in the above embodiment, the case where the object to be drawn is a door panel for an elevator has been described. However, the present invention is not limited to this. It is possible to apply.

[0035]

As described above, according to the present invention, when irradiating a laser beam to a photocurable resin applied to the surface of an object to be drawn, the scanning speed of the laser beam is varied. Since the curing width of the photocurable resin is variable, the resolution and gradation can be adjusted without using a conventionally used zoom mechanism, and the apparatus can be simplified. Will be possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a main part of a direct drawing apparatus according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing light intensity characteristics of a laser beam 8 in FIG.

FIG. 3 is an explanatory diagram showing a cured shape of the UV ink 2 when the laser beam 8 is irradiated while being stopped.

FIG. 4 is an explanatory diagram showing a cured shape of the UV ink 2 when the laser beam 8 is irradiated while scanning.

FIG. 5 is a characteristic diagram showing a relationship between a curing width W and a scanning speed V.

FIGS. 6A and 6B are cross-sectional views showing the shapes of a cured portion 2a and an uncured portion 2b in the UV ink 2 when the scanning speed V is varied. FIG. Shows the case where the speed is slow.

FIG. 7 is an explanatory diagram showing a change in a curing width corresponding to a change in a scanning speed.

FIG. 8 is a perspective view showing a main configuration of a direct writing apparatus according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Panel (drawing target object) 1a Front surface 2 UV ink (photocurable resin) 2a Cured part 2b Uncured part 3 Zoom mechanism 4 Lens system 5 Motor 6 Laser irradiation part 7 Laser irradiation port 8 Laser light 9 Scan control part 10 Scanning Speed control means 11 Laser light intensity characteristic curve 12 Scanning speed characteristic curve 13 Beam shape

Claims (4)

[Claims] A photo-curable resin applied to the surface of an object to be drawn is irradiated with a laser beam scanned based on predetermined pattern information. By removing the uncured portion of the photocurable resin while leaving, in a direct drawing method of drawing a desired pattern on the surface of the drawing object, by changing the scanning speed of the laser beam, A direct drawing method characterized by varying a curing width. 2. A laser beam is applied to a photo-curable resin applied to the surface of the object to be drawn so as to be opposed to the object to be drawn and scan the surface of the object. A laser irradiation unit, and a scanning control unit that controls the scanning of the laser beam based on predetermined pattern information. The scanning control unit variably controls a scanning speed of the laser beam. A direct drawing apparatus having speed control means. 3. The laser irradiation unit is movable in XY directions along the surface of the object to be drawn, and the scanning speed control means controls the moving speed of the laser irradiation unit. The direct drawing apparatus according to claim 2, wherein the scanning speed of the laser beam is variably controlled. 4. The laser irradiation section has mirror means for changing the irradiation angle of laser light on the surface of the object to be drawn, and the scanning speed control means controls the irradiation angle change speed of the mirror means. The direct drawing apparatus according to claim 2, wherein the control is performed to variably control a scanning speed of the laser beam.