Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1999-06-16
2001-04-03
Le, N. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S241000
Reexamination Certificate
active
06211900
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an improvement in a laser cutting machine (referred to as a “recording apparatus”, hereinafter).
BACKGROUND ART
A recording apparatus has been known which has, as shown in
FIG. 1
, a recording laser
1
and a focusing laser
3
. In operation of this recording apparatus, initial setting of optimum focusing position of a recording lens
21
is performed in accordance with the following procedure. As the first step, a head
19
is positioned at an optimum position by means of a head positioning mechanism
17
, while a resist master disk
20
is not rotating. Then, the master disk
20
is driven to rotate at a predetermined speed and, when the disk rotation has become steady at that speed, the recording laser
1
is activated so that recording laser light is made to be incident to the master disk
20
via mirrors
5
,
7
and
9
and then through a recording lens
21
. The laser light reflected by the master disk
20
runs backward along the same optical path as the incident light so as to impinge upon a CCD camera
13
from the mirror
5
, whereby a laser spot image is formed on the monitor
15
through the camera
13
. The operator, while visually observing the state of the laser spot image, controls a motor driver
29
so as to control a motor
27
thereby moving a photo-detector (PD) to the left and right. A servo circuit
31
performs a fine control of the position of the recording lens in the up and down directions so as to position the recording lens
21
at such a position that the above-mentioned laser light impinges upon the center of the PD
23
which is set at a position as a result of the above-mentioned control performed by the operator. This operation is repeated so that the recording lens
21
is set at the optimum focusing position.
In the above-described operation for initially setting the recording lens
21
at the optimum position, the laser spot image of the recording laser light displayed on the monitor
15
linearly changes in accordance with the movement of the PD
23
, because the laser spot light is analog information. Considerably high degrees of skill and experience, therefore, are required in order to adequately position the recording lens
21
by visually finding the laser spot image corresponding to the optimum focusing position of the recording lens
21
through continuous visual chasing of the change in the laser spot image. The optimum focusing position of the recording lens
21
delicately varies according to the type of the resist master disk. Therefore, the above-described work is considerably troublesome even for skilled and experienced operators. Thus, it is not easy to position the recording lens
21
with a high degree of accuracy.
The described recording apparatus suffers from another disadvantage in that, even if the recording lens
21
has been set at the optimum focusing position, the data indicative of such optimum focusing position cannot be relied upon for the purpose of reproduction of the optimum focusing position, because the data is analog data which is in the form of the laser spot image displayed on the monitor
15
and cannot be stored.
Consequently, the above-described troublesome work is necessarily conducted each time the type of the resist master disk is changed, thus impairing the efficiency of the whole process.
Accordingly, an object of the present invention is to provide a recording apparatus in which the data indicative of the optimum focusing position of the recording lens is changed into numerical values so as to facilitate the work for initially setting the optimum focusing position of the recording lens for each type of resist master disk.
DISCLOSURE OF THE INVENTION
To this end, the present invention provides a recording apparatus for exposing a resist master disk to a recording laser light through a recording lens which has been set at an optimum focusing position, comprising: displaceable laser light detecting means for receiving a focusing laser light which has been applied to and reflected from the resist master disk during initial setting of the optimum focusing position, and for producing a detection signal indicative of the amount of deviation, from a predetermined light receiving position, of the light receiving position where the reflected focusing laser light is received; servo means responsive to the detection signal so as to automatically adjust the relative position of the recording lens with respect to the resist master disk in such a manner as to eliminate the deviation, thereby setting the recording lens at the optimum focusing position; displacement amount detecting means for detecting the amount of displacement of the laser light detecting means; and display means for changing the output from the displacement amount detecting means into numerical values and displaying the numerical values.
According to the features of the recording apparatus set forth above, the amount of displacement of the laser light detecting means acquired in the course of an initial setting performed by a skilled operator is changed into a numerical value which can be relied upon in the next initial setting of the optimum focusing position. The next initial setting, therefore, can easily be conducted even by an operator who is not so skilled. By holding the numerical optimum focusing position data for each of a plurality of types of resist master disks, initial setting of the optimum focusing position can easily be executed each time a different type of resist master disk is used, thus achieving a further improvement in the efficiency of the whole process.
Preferably, the recording apparatus in accordance with the present invention further comprises: reference displacement amount setting means in which a reference displacement amount has been set in terms of the amount of the displacement required to obtain coincidence between the light receiving position at which the focusing laser light is received and the reference light receiving position under such a condition that the recording lens has been set at the optimum focusing position; and automatic displacement amount adjusting means for automatically adjusting the displacement amount of the laser light detecting means such that the detection output from the displacement amount detecting means coincides with the reference displacement amount.
Thus, a preferred form of the recording apparatus in accordance with the present invention has reference displacement amount setting means and automatic displacement amount adjusting means.
The reference displacement amount setting means sets a reference displacement amount in terms of the amount of displacement required for achieving coincidence between the light receiving position at which the focusing laser light is received and the reference light receiving position under such a condition that the recording lens has been set at the optimum focusing position. The automatic displacement amount adjusting means automatically adjusts the amount of the displacement of the laser light detecting means such that the detection output from the displacement amount detecting means coincides with the reference displacement amount.
In the preferred form of the present invention set forth above, the amount of displacement of the laser light detecting means is automatically adjusted such that the detected displacement amount coincides with the reference displacement amount. Thus, the amount of displacement of the laser light detecting means can be automatically adjusted without troubling the operator.
REFERENCES:
patent: 4209793 (1980-06-01), Ueno
patent: 5161046 (1992-11-01), Ohshima et al.
patent: 5444681 (1995-08-01), Ishiwata et al.
patent: 63-46311 (1989-10-01), None
patent: 1-151428 (1989-10-01), None
patent: 3-181032 (1991-08-01), None
patent: 7-73491 (1995-03-01), None
Harness & Dickey & Pierce P.L.C.
Le N.
Nguyen Lamson D.
Seiko Epson Corporation
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