JPH059703Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to a laser scanning optical device, and more specifically, a laser scanning optical device that can be applied to a multi-point synchronized laser scanning optical system such as a laser recording device, a laser reading device, etc. It is related to.

(Prior art) A grating placed on the scanning optical path of a laser beam for clock generation and a plurality of condensing elements that condense the laser beam that has passed through this grating are arranged in a row with a width corresponding to the scanning line length. A light-concentrating section consisting of an array of arranged condensing elements, and a light-receiving section consisting of a number of light-receiving elements corresponding to the number of the above-mentioned condensing elements that receive the scanning light condensed by each of the above-mentioned condensing elements. There is a laser scanning optic.

In such a laser scanning optical device, the grating and the condensing element array are each attached and fixed to separate holding members, and their optical positions are adjusted separately. Therefore, there is a drawback that individual adjustments are troublesome. Furthermore, since this adjustment is performed with the laser scanning optical device assembled in the laser scanning optical unit, a space must be secured for tools and hands, making the work difficult and time consuming.

Alternatively, as another adjustment means, there is a method in which a grating is fixed to one side of the reference part of the holding member having an opening, and a condensing element array is fixed to the other side of the reference part using a spring or an adhesive. However, even in this case, the position, inclination, inclination, etc. of the grating and the condensing element array must be adjusted individually with respect to the optical axis, and the mutual positional relationship between the two must be adjusted. It relies on the reference part of the holding member. In other words, since the above positional relationship is achieved by bringing the grating and the condensing element array into contact with the reference part, precision in processing the reference part is required.

(Objective) Therefore, it is an object of the present invention to provide a laser scanning optical device that allows easy adjustment of gratings and condensing element arrays.

(Structure) In order to achieve the above object, the present invention integrally attaches the grating and the condensing element array using a holding member and a pressing member, and the pressing member is attached to both ends of the holding member in the scanning direction. One pressing member is made of an elastic member and has the function of pressing the grating and the condensing element array in the optical axis direction and simultaneously pressing the grating in the scanning direction, and the other pressing member is provided in the grating. and an elastic means for pressing the converging element array at least in the optical axis direction, and the grating is adjusted in the scanning direction at at least one of both ends in the scanning direction.

The present invention will be specifically described below based on one embodiment of the present invention.

FIG. 8 shows an example of a general multi-point synchronization type laser recording device using a lens in a condensing element array.

In the figure, a recording laser beam and a synchronous clock generation laser beam emitted from a semiconductor laser 11 as a recording light source consisting of a directly modulated semiconductor laser and a synchronous clock generation laser light source 12 are emitted by a collimating lens 13,
14, are combined by a polarizing beam splitter 15, pass through a cylinder lens 16 for beam shaping, are deflected at a slightly distant position on the same mirror surface on a rotating polygon mirror 17, and then pass through an fθ lens 18. , the recording laser beam is mirror 19
The synchronized clock generating beam scans over the grating 21.

This grating 21 is a well-known grating in which minute bright and dark areas are alternately arranged along the scanning direction of the laser beam, and is also called a slit, a grid, a scale, or the like.

The laser beam transmitted through the bright area on the grating 21 is directed to each lens 221 of the condensing element array 22, which is a lens array in which a plurality of lenses 221 to 22n are arranged in a row with a width corresponding to the scanning line length.
The light is focused by ~22n, and this lens 221~2
The light is received and photoelectrically converted by each of the light receiving elements 231 to 23n of the light receiving section 23, which includes the same number of light receiving elements 231 to 23n.

The output signals of the light receiving elements 231 to 23n are respectively amplified by amplifiers 241 to 24n, added by an adder 25, and waveform-shaped by a waveform shaper 26 to form a series of pulse trains.

This pulse train is a PLL (Phase Locked Loop)
A clock control circuit 27 consisting of a circuit serves as an image clock (synchronized clock), and a laser drive modulation circuit 28 synchronizes with the image clock and modulates the semiconductor laser 11 according to information from an information source 29, thereby controlling the recording medium. Information is written to 20.

During writing of this information, even if the scanning speed of the laser beam changes due to uneven rotation of the rotating polygon mirror 17, the timing at which the image clock is generated changes accordingly, so that jitter is reduced. Further, the laser light source 12 for generating a synchronous clock is driven by a laser drive circuit 30.

In the optical system having the above configuration, as shown in FIG.
22n integrally with a holding member (indicated by a dashed line), and grating 21 and lenses 221 to 22n.
22n were brought into contact with each other.

Furthermore, only grating 21 is lens 221.
An adjustment mechanism was provided that could slide on the contact surface with ~22n to adjust the position in the scanning direction. The entire structure was then made into a lens unit.

The holding member 31 has a reference part perpendicular to the laser beam so that the laser beam enters each lens 221 to 22n perpendicularly when the optical system is viewed from the side.
Place the lens against this reference part and install it.

The grating 21 is also configured so that the laser beam is perpendicularly incident thereon, and furthermore, as shown in FIG. I have to.

At this time, the perpendicularity to the laser beam is such that the surface of the grating 21 is
Since it is brought into contact with the end face of the convex portion of n, it can be easily taken out.

When fixing the lens unit 32, in which the grating 21 and the lens array 22 are attached to the holding member 31, to the laser scanning optical unit 33 (see FIG. 5), the focus of each lens 221 to 22n constituting the condensing element array 22 is adjusted. Each light receiving element 2 at the position
31 to 23n are located.

Next, specific means for integrally attaching the grating and the condensing element array using the holding member and the pressing member will be explained with reference to FIGS. 1 to 6.

The holding member 31 is composed of a long block,
A hole for screwing, a hole for positioning, and an elongated hole are provided at both ends in the longitudinal direction, and a pin 42 is provided at a predetermined position of the laser scanning optical unit 33.
It is positioned and fixed with screws 43.

A groove 31-a is provided in the middle part of this holding member 31 so that the condensing element array 22 is attached, and this groove 31-a is long in the scanning direction, and each Lenses 221 to 22n are abutted against each other to prevent inclination in the optical axis direction so that the laser beam enters perpendicularly.

Further, the holding member 31 is provided with grooves 31-a so as to adjust the movement of the grating 21 in the scanning direction.
A groove 31-c is formed that is slightly wider than the groove 31-c.

Then, the grating 21 is attached so as to come into contact with the convex lens surface of the condensing element array 22 attached to the groove 31-a, and the springs 34 and 39 provided at both ends of the holding member 31 are attached to the grating 21.
and the condensing element array 22 are simultaneously pressed in the optical axis direction. Note that the condensing element array 22 has grooves 31-
It may be attached to a.

As shown in FIG. 2, the spring 34 has a bent portion 35 that acts to press the grating 21 in the direction of the optical axis and a bent portion 3 that acts to press the grating 21 in the scanning direction.
It is equipped with 6.

Two holes are provided for attachment to the holding member 31 with screws 38.

The other spring 39, as also shown in FIG. 3, has only a bent portion 35 that acts to press in the optical axis direction.

A screw hole 40 is opened in the scanning direction on the side of the holding member 31 on the spring 39 side, and a groove 31-
It penetrates c.

An adjustment screw 41 is screwed into this screw hole 40 so that the tip of the adjustment screw 41 comes into contact with the side surface of the grating 21.

Therefore, when this adjustment screw 41 is rotated, the inner surface 31-d of the groove 31-c moves the grating 21 in the scanning direction with the bending portion 36 of the spring 34 on the opposite side as a guide for adjustment. be able to. At this time, the grating 21 is connected to the lens array 22.
is in contact with the convex surface of the lens.

After adjustment, the adjusting screw 41 is fixed by screwing a fixing screw into a screw hole provided perpendicularly to the screw hole 40 (not shown), or simply gluing the adjusting screw 41 to the holding member 31. to fix the position.

Next, the significance of adjusting the scanning direction of the grating 21 will be explained. This adjustment is performed because the laser beam that has passed through the bright and dark areas of the grating 21 is vignetted by the edges of the lenses 221 to 22n.
This is done in order to match the edges of the lenses 221 to 22n with the dark portions of the grating 21, since each of the light receiving elements 231 to 23n cannot receive light and the pulse signal is missed in that portion.

Therefore, the adjustment movement amount of the grating 21 is
All you need is the pitch of grating 21, so
The thread pitch of the adjustment screw 41 is grating 21.
It is better to make it the same as or less than the pitch.

As explained above, by integrating the grating and the condensing element array, they can be fixed at the same time using the pressing member, and the mutual relationship can be adjusted at a stage before they are incorporated into the laser scanning optical unit. .

Therefore, no adjustment is required when incorporating the condensing element array into a laser scanning optical unit.

Furthermore, in this example, the adjustment mechanism is made compact and easy to perform adjustment work, so adjustment is easy even after it is incorporated into the laser scanning optical unit.

(Effects) According to the present invention, the grating and the condensing element array can be easily adjusted, which is advantageous.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the adjustment mechanism according to the present invention, Figure 2 is a perspective view of the adjustment mechanism according to the present invention;
Figure 3 is a perspective view of the pressing member, Figure 4 is a vertical sectional view of the adjustment mechanism shown in Figure 1, Figure 5 is a plan view of the adjustment mechanism, and Figure 6 is the right end of the adjustment mechanism. 7 and 8 are schematic configuration diagrams of the laser recording apparatus. 21... grating, 22... condensing element array, 31... holding member, 34, 39... spring,
41...adjustment screw.

Claims (1)

[Claims for Utility Model Registration] A grating disposed on the scanning optical path of a laser beam for clock generation, and a plurality of condensing elements that condense the laser beam that has passed through the grating, with a width corresponding to the scanning line length. a light-receiving section comprising a light-collecting element array arranged in a row, and a light-receiving element having a number corresponding to the number of light-receiving elements, each of which receives the scanning light focused by each of the light-collecting elements; In the laser scanning optical system, the grating and the condensing element array are integrally attached by a holding member and a pressing member, and the pressing member is provided at both ends of the holding member in the scanning direction, One pressing member is an elastic member that presses the grating and the condensing element array in the optical axis direction and simultaneously presses the grating in the scanning direction. A laser scanning optical device comprising an elastic means for pressing an optical element array at least in the optical axis direction, and the grating is adjusted in the scanning direction by an adjusting member provided at at least one of both ends in the scanning direction.