JP2005106866A - Focusing device for laser marking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a focusing device for a laser marking device for manually or automatically adjusting the focus displacement generated when assembling the laser marking device and when replacing a laser unit. <P>SOLUTION: Regarding the laser marking device provided with the laser unit 1, a fixed lens L1, a focusing lens L2, a scanner unit 2 and an fθ lens 3, a sampler 4 is arranged between the focusing lens L2 and the scanner unit 2 so as to reflect some of laser beams and separate the beams, and also, the beam diameter of the laser is detected by a sensor 5 through a condensing lens L3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a focus adjustment device that facilitates a focus adjustment operation of a laser marking device.

  In the conventional laser marking apparatus shown in FIG. 1, when the laser unit 1 is replaced for maintenance or the like, the laser head varies from laser unit to laser unit, so the spread angle of the laser beam is different. Deviated from the marking surface M, and readjustment was necessary.

In this adjustment, the focus adjustment lens L2 is moved little by little in the optical axis direction, marking is actually performed so that the focus position comes to the marking surface M, and the focus position is observed while observing the marking state and observing the best state. It is very time consuming to make adjustments. In the figure, 2 is a scanner unit and 3 is an f · θ lens.
Japanese Patent Laid-Open No. 3-124486

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a focus adjustment device for a laser marking device that manually adjusts or automatically adjusts a focus position shift that occurs when the laser marking device is assembled or when the laser unit 1 is replaced. It is what.

  The present invention has been made to solve the above problems, and the first invention provides a focus adjustment lens disposed between a laser unit and a scanner unit and a laser beam sampler provided between the scanner unit and a laser beam. Focus adjustment of a laser marking device characterized in that a part of the laser beam is reflected and imaged on a sensor for measuring the beam diameter via a condenser lens, and the sensor is fixed at a position where the laser beam diameter becomes a predetermined diameter Device.

  A second invention is an automatic focus adjustment device for a laser marking device in which focus adjustment is automated, and includes a focus adjustment lens disposed between a laser unit and a scanner unit, and a laser beam sampler provided between the scanner unit. A part of the laser beam is reflected and focused on a sensor that measures the laser beam diameter via a condenser lens, and the focus adjustment lens is controlled by the control device so that the focused laser beam diameter becomes a predetermined diameter. Is driven in the optical axis direction.

  In the manual focus adjustment apparatus of the first invention, a laser beam sampler is provided in the optical path of the laser beam, and a sensor for detecting the diameter of the laser beam is provided through the sampler. The focus adjustment operation can be completed easily and quickly by finely moving the focus adjustment lens so that the diameter becomes an appropriate diameter (usually the minimum diameter).

  In the second invention, the focus adjustment lens is driven by the control device so that the laser beam diameter detected by the sensor becomes an appropriate value (usually the minimum value). Is done.

  FIG. 2 shows a manual type embodiment of the present invention. In the laser marking apparatus comprising a laser unit 1, a fixed lens L1, a focus adjustment lens L2, a scanner unit 2, and an f · θ lens 3, the focus is described. A laser beam sampler 4 is provided between the adjustment lens L2 and the scanner unit 2 to divide a part of the laser beam and to detect the laser beam diameter by the sensor 5 via the condenser lens L3. is there.

  Thus, in this embodiment, the initial adjustment is performed to focus on the marking surface M. At that time, a part of the laser beam is reflected by 45 ° by the sampler 4 provided after the focus adjustment lens L2, and the condensing lens L3. Then, the image is formed on the sensor 5 for measuring the laser beam diameter, and the sensor 5 is fixed at a position where the laser beam diameter is minimized.

  When the laser unit 1 is replaced and the spread angle of the laser beam is changed, the marking surface M and the focus position are shifted as shown by the dotted line in FIG. At this time, the beam diameter on the sensor is also increased. Therefore, when the focus adjustment lens L2 is moved to adjust the focus position to the marking surface M, the beam diameter should be observed by the sensor 5 so as to be minimized, so that the focus adjustment can be performed in a shorter working time than before. Is possible.

  FIG. 3 shows an embodiment of the second invention. The laser marking apparatus including the laser unit 1, the fixed lens L1, the scanner unit 2, the f · θ lens 3 and the sampler 4 is the same as the embodiment described above. Although it is the same, in order to automate, the structure is different as follows.

  That is, in order to electrically drive the focus adjustment lens L2, a focus adjustment lens unit 6 with VCM as shown in FIG. 4 is used. In this focus adjustment lens unit 6, the lens L 2 is attached to a movable lens barrel 62 having a coil 61, and the movable lens barrel 62 has an inside of a double fixed lens barrel 62 having a magnet 63 depending on the intensity of current flowing through the coil 61. It is configured to move in the optical axis direction.

  The focus adjustment lens L2 is controlled by the control device 7 in accordance with the detection signal of the sensor 5 '.

  The focus detection unit of the sensor 5 ′ uses a four-divided light receiving element used for focus control of an optical disk or the like, for example, and detects the focus position by an astigmatism method. Focus adjustment is performed by driving the focus adjustment lens via the device 7. In this case, a cylindrical lens L4 is provided between the condenser lens L3 and the sensor 5 '.

  According to the above configuration, if the laser beam diameter is set to be minimized in advance, proper automatic focus adjustment is always performed, and even when the laser unit 1 is replaced, troublesome focus adjustment is performed as in the past. No need to do it manually.

Explanatory drawing about the focus adjustment in the conventional laser marking apparatus. The block diagram of the Example of 1st invention. The block diagram of the Example of 2nd invention. FIG. 4 is a partially cut enlarged side view showing the structure of a focus adjustment lens unit used in the embodiment shown in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser unit 2 Scanner unit 3 f * theta lens 4 Sampler 5 Sensor 6 Focus adjustment lens unit 7 Controller

Claims (2)

In a laser marking device in which a laser unit, a fixed lens, a focus adjustment lens, a scanner unit, and an f / θ lens are sequentially arranged, a laser beam sampler is provided between the focus adjustment lens and the scanner unit, and a part of the laser beam A focus adjustment device for a laser marking device, wherein a laser beam diameter is detected by a sensor through a condensing lens while reflecting the light. In a laser marking device in which a laser unit, a fixed lens, a focus adjustment lens, a scanner unit, and an f / θ lens are sequentially arranged, a laser beam is provided between the focus adjustment lens arranged between the laser unit and the scanner unit and the scanner unit. A sampler is provided to reflect and split a part of the laser beam and form an image on a sensor that measures the laser beam diameter via a condenser lens so that the imaged laser beam diameter becomes a predetermined diameter. An automatic focus adjustment device for a laser marking device, wherein the control device drives the focus adjustment lens in the optical axis direction.

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