KR200339961Y1 - Laser scaning unit - Google Patents

Abstract

A base; A drive motor installed at the base and providing rotational force; A deflection disk installed in the drive motor, the deflection disk having a hologram pattern formed to diffractively deflect incident light, and forming a scanning line by rotation; A light source module installed at the base so as to face one surface of the deflection disk, the light source module irradiating light to one incident position of the deflection disk; One end is supported by the light source module and the other end is fixed and deformed according to the temperature change, the light source module position adjusting means having a bimetal for rotating the light source module, including; An optical scanning unit is disclosed in which the center of light deflected by the deflection disc is scanned at the same diffraction angle with respect to the deflection disc by being rotated and positioned relative to the base.

Description

Optical scanning unit {Laser scaning unit}

The present invention relates to an optical scanning unit using a deflection disk, and more particularly, to an optical scanning unit capable of adjusting an installation position of a light source for a deflection disk.

In general, an optical scanning unit using a deflection disk is a device for diffracting and scanning laser light incident on a hologram pattern of a deflection disk by rotation of the deflection disk.

Referring to FIG. 1, a conventional optical scanning unit includes a drive source 1 for providing a rotational force, a deflection disk 3 partitioned into a plurality of sectors installed in the drive source 1 and each having a hologram pattern, and the deflection; At least one light source 5 disposed opposite one surface of the disk 3 to scan laser light, and an optical member 7 for converting the correction path and the path of correction of the scanning line L diffracted and deflected from the deflection disk 3; It is configured to include).

The light source 5 is a semiconductor laser that irradiates a point P of the deflection disk 3 with light of a predetermined wavelength, for example, approximately 785 nm. This light source 5 is fixedly arranged so that its optical axis becomes an angle θ with respect to the rear surface of the deflection disk 3. When the deflection disc 3 rotates at a predetermined angular velocity, the scanning line L irradiated and deflected by the light source 5 has its optical direction 7 at an angle α with respect to the rear surface of the deflection disc 3. 1 mirror (M). Here, the diffraction deflection conditions of the deflection disc 3 are the same, and the installation angle of the light source 5 is equal to each other. In this case, the diffraction angle α is changed to an angle α ₁ or a larger angle α ₂ than the angle α in the direction shown by the dotted line according to the wavelength change of the light emitted from the light source 5.

On the other hand, the light source 5 has an error of approximately ± 10 nm at a desired wavelength, for example, 785 nm due to errors due to mode hopping, drift, drop, and the like. Here, mode hopping refers to a phenomenon in which the main oscillation mode of the laser is shifted by injection current, temperature, optical feedback, and the like. The degree of shift depends on the cavity length of the laser diode and the oscillation wavelength difference between adjacent modes is about 0.3 to 0.5 nm. The drift is a wavelength that changes according to temperature change, etc., in a narrow sense, means the effect of the change in the cavity length, and in a broad sense, it also means a wavelength change in accordance with the temperature including the mode hopping. The droop means the reduction ratio of the amount of emitted light after a predetermined time has elapsed with respect to the first peak power when the laser diode is turned on.

Therefore, when fixing the installation position of the said light source with respect to the said deflection disc 3, it is difficult to match the desired diffraction angle (alpha). Accordingly, in order for the scan line to be formed at a predetermined position, optical alignment with respect to each of the plurality of optical members 7 is required, and thus, assembly work is complicated and correct scanning is difficult.

In view of the above problems, the present applicant has filed a patent for the optical scanning device as shown in FIG.

Referring to FIG. 2, the light scanning unit is a moving means installed at the lower side of the base 10 to move the light source module 20 for irradiating light to the deflection disc 12. An elastic member 32 for elastic bias in one direction, a support piece 34 for supporting the light source module 20 and an adjustment screw 36 are provided. The adjusting screw 36 is mounted to the base 10 so that its end contacts the mount 22 of the light source module 20.

In the above configuration, the adjustment screw 36 is rotated to adjust the position of the light source module 20 so that the path of the light irradiated from the light source module 20 to one incident position P of the deflection disk 12 is adjusted. It can be adjusted. Therefore, during initial setting of the light source module 20, by adjusting the position of the light source module 20 using the adjustment screw 36, the diffracted deflected scan line L on the deflection disc 12 is directed to the same position. It was.

By the way, such an optical scanning unit has to be adjusted by the operator manually the position of the light source module 20. Therefore, even if the desired diffraction angle α is set at the time of initial setting, there is a limit that it is difficult to actively cope with the change of the wavelength of light in response to the temperature change.

The present invention was devised to solve the above problems, and the optical scanning is made to maintain the diffraction angle constant by actively adjusting the incident angle of the light irradiated from the light source and incident at one incident position of the deflection disk according to the temperature change. The purpose is to provide a unit.

1 is a schematic view showing an optical scanning unit using a conventional deflection disk.

Figure 2 is a schematic front view showing a photowangsa unit as proposed by the applicant.

Figure 3 is a schematic diagram showing the main portion of the optical scanning unit according to an embodiment of the present invention.

4 is a schematic front view showing an optical scanning unit according to an embodiment of the present invention.

Figure 5 is a perspective view showing a base of a photowangsa unit according to an embodiment of the present invention.

6 is a plan view showing an optical scanning unit according to an embodiment of the present invention.

Figure 7 is an exploded perspective view showing a light source module of the optical scanning unit according to an embodiment of the present invention.

8 is a cross-sectional view showing a light source module of an optical scanning unit according to an embodiment of the present invention.

Figure 9 is a perspective view showing a support piece of the optical scanning unit according to an embodiment of the present invention.

10 is a schematic cross-sectional view showing an optical scanning unit according to another embodiment of the present invention.

11 is a schematic perspective view showing an optical scanning unit according to another embodiment of the present invention.

12 is an exploded perspective view showing a light source module of the optical scanning unit according to another embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

40,140..Base 41..Through hole 45..Guide part

50. Driving motor 60. Deflection disc 70, 170. Light source module

71,171..light source 73,173..mount 77,177 .. barrel

81. Stud 83. Support 85. Support bracket

87,187 Bimetal 88 Support member 89,183 Fastening member

91 .. Focusing lens 93,193 .. Aperture stop 185. Protrusion pin

Optical scanning unit according to the present invention for achieving the above object, the base; A driving motor installed at the base and providing rotational force; A deflection disk installed in the drive motor, the deflection disk having a hologram pattern formed to diffractively deflect incident light, and forming a scan line by rotation; A light source module installed at the base so as to face one surface of the deflecting disk, wherein the light source module irradiates light to one incident position of the deflection disk; And a light source module position adjusting means having one end supported by the light source module and the other end fixed and deformed according to a temperature change, and having a bimetal rotating the light source module. By rotating and positioning about the base about one incidence position, the center of light deflected and scanned by the deflection disc is scanned at the same diffraction angle with respect to the deflection disc.

Hereinafter, an optical scanning unit according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 and 4, an optical scanning device according to an embodiment of the present invention includes a base 40, a drive motor 50 installed on the base 40 to provide rotational force, and a deflection disk 60. ), A light source module 70 for irradiating light to one incident position of the deflection disc 60, and a light source module position adjusting device.

Referring to FIG. 5, the base 40 has a through hole 41 through which the light emitted from the light source module 70 passes, and is formed on a rear surface of the base 40 to guide the adjustment of the light source module 70. The part 45 is provided. The guide portion 45 is formed to be convex in a semi-cylindrical shape, and its outer circumferential surface 45a is a curved surface centering on one incidence position P of the deflection disk 60. In addition, the base 40 is formed with a hollow 40a in which a stud (81 of FIG. 4) used to couple a portion of the light source module position adjusting means is installed. Here, the base 40 may include a plurality of through holes 41 and a plurality of guide parts 45 as shown, so that the base 40 may be employed when a plurality of light source modules are mounted.

The drive source 50 is installed in the base 40, and rotates the deflection disc 60 at a predetermined angular speed. 4 and 6, the deflection disc 60 has an area 61 provided in the drive source 50 and partitioned into a plurality of sectors each having a hologram pattern, and diffracted deflects incident light by rotation. The scanning line L is formed.

4, 7 and 8, the light source module 70 is installed on the base 40 so as to be opposite to one surface of the deflection disk 60, for example, the back surface of the deflection disk 60. Light is irradiated to one incident position P. FIG. The light source module 70 includes a light source 71 and a mount 73 having a light guide 71 on which the light source 71 is mounted and which is slidably positioned on the guide part 45. The light source 71 irradiates laser light of a predetermined wavelength, and the irradiated light passes through a through hole (41 in FIG. 5) of the base 40 and is incident on the deflection disc. Here, the guide surface 73a is preferably a curved surface centering on one incidence position P of the deflection disk 60, as shown in the outer circumferential surface (45a of FIG. 5) of the guide portion 45. In addition, the light source module 70 is fitted into the through-hole 41 and is coupled to the mount by the fastening portion 79, and installed in the barrel 77 and irradiated from the light source 71 A focusing lens 91 for focusing the collected light and an aperture stop 93 for limiting the transmission region of the focused light by the opening 93a formed in a predetermined size and shape to provide light having a desired size and shape. It includes more.

Here, each of the base 40 and the mount 73, the first and second regulatory portion 45b for regulating the movement direction of the mount 73 so that the position adjustment direction of the light source module 70 is one direction 75 is provided. The first regulation part 45b is a guide groove formed around the passage hole 41 of the guide part 45, and the second regulation part 75 corresponds to the first regulation part 45b. It is a guide protrusion protruding from the guide surface 73a of the mount 73. Here, the shapes of the first regulatory part 45b and the second regulatory part 75 may be interchanged.

The light source module position adjusting means has one incidence position P of the deflection disc 60 such that the center of the light scanned by the deflection disc 60 is scanned at the same diffraction angle α on the deflection disc 60. The light source module 70 is automatically rotated with respect to the base 40 in accordance with the temperature change to adjust the incident angle between the light source module 70 and the deflection disk 60. Referring to FIG. 2, when the incidence angle θ of the light source module 70 is used as a reference, the light wavelength irradiated from the light source 71 is adjusted by the influence of temperature by adjusting to a smaller incidence angle θ ₁ or a larger incidence angle θ ₂ . Even if it changes, the light is diffracted at the same diffraction angle α.

The light source module position adjusting means is supported by the bimetal 87 for rotating the light source module 70 and the guide surface 73a of the mount 73 to be in contact with the guide part 45 while being deformed by temperature change. The support piece 83 is provided below, the support 73 for clamping one end of the bimetal 87, and a support bracket 85 for fixing the other end of the bimetal 87.

The bimetal 87 has a structure in which thermal expansion coefficients are coupled to face metals having different thermal expansion coefficients. The bimetal 87 is widely used in the industry to have a property that each metal is deformed to different lengths as the temperature changes, so that one end thereof is bent to one side. The bimetal 87 is fixed and supported by a fastening member 89 having the other end coupled to the support bracket 85. In addition, the bimetal 87 may be directly fixed to the support bracket 85 by press fitting.

4 and 9, the support piece 83 is installed to be in contact with one side of the mount 73, and supports the mount 73 to be slidably in contact with the guide part 45. . The support piece 83 is provided with an installation hole 83a at one end thereof to be fitted to the stud 81, and the other end thereof is fastened to the bottom surface of the base 40. In addition, a hole 83b having a sufficient size is formed in the central portion of the support piece 83 so that the bimetal 87 passes and does not interfere even when moved a predetermined distance.

7 and 8, the support part includes a support member 88 provided below the mount 73. The support member 88 has a locking protrusion 88b protruding from each other at both ends thereof as a means for being fastened to the mount 73. In addition, an insertion hole 88a into which one end of the bimetal 87 is inserted without movement is formed at a central portion of the support member 88. In this case, the support member 88 may be formed integrally with the mount 73, and a groove (not shown) may be formed at a position corresponding to the bimetal 87 to allow one end of the bimetal 87 to be clamped. have.

As shown in FIG. 4, the support bracket 85 is fastened together with the support piece 83 below the base 40. The fastening member 89 is fastened to one side of the support bracket 85.

In the above configuration, the position of the light source module 70 is adjusted by the deformation of the bimetal 87 only when there is a change in temperature. That is, when the temperature rises or falls, the bimetal 87 deforms to one side and presses the light source module 70. Therefore, the light source module 70 is closer to the stud 81 while being in contact with the guide portion 45 by the support piece 83 about the one incident position P of the deflection disk 60. Or in the opposite direction.

Therefore, in the state where the light source module 70 is initially set such that the diffraction angle α is the same, the wavelength of the light irradiated from the light source 71 is changed according to the temperature change so that the initially set diffraction angle α is changed. Even if the bimetal 87 is deformed as the temperature changes, the position of the light source module 70 is automatically adjusted, so that the scanning line L diffracted and deflected on the deflection disc 60 is directed to the same position.

10 and 11, an optical scanning unit according to another embodiment of the present invention includes a base 140, a driving motor 50 installed on the base 140 to provide rotational force, and a deflection disk ( 60), the light source module 170 and the light source module position adjusting means for irradiating light to one incident position of the deflection disk (60).

The base 140 has a receptacle 141 which is formed to be retracted from an upper surface thereof to slidably receive the light source module 170. The accommodating portion 141 has a bottom surface 141a which is formed to be concave downward, and is a curved surface centering on one incidence position P of the deflection disk 60. In addition, the accommodating part 141 has a groove drawn in from the side thereof, so that a part of the light source module position adjusting means is movable to be accommodated. Here, the base 140 may be provided with a plurality of receiving portions 141, as shown, so as to employ a plurality of light source modules.

10, 11 and 12, the light source module 171 is installed to be accommodated in the receiving portion 141 so as to face the rear surface of the deflection disk 60 and the deflection disk 60. The light is irradiated to one incident position P of. The light source module 170 includes a light source 171 and a mount 173 having a light source 171 and a guide surface 173a on which the light source 171 is mounted and slidably contacts the bottom surface 141a. The light source 171 irradiates a laser light having a predetermined wavelength to one incident position P of the deflection disk 60. Here, the guide surface 173a is preferably a curved surface centering on one pressing position P of the deflection disk 60, similarly to the bottom surface 141a. In addition, the light source module 170 has a barrel 177 coupled to the mount 173 by a fastening unit 179. The barrel 177 is provided with a focusing lens (not shown) for focusing the light irradiated from the light source 171. In addition, the barrel 177 is further provided with an aperture stop 193 which provides light of a desired size and shape by limiting a transmission area of light focused by the opening 193a formed in a predetermined size and shape.

The light source module position adjusting means is fixed with respect to the base 140 and is thermally expanded and deformed by a temperature change, thereby adjusting the position of the light source module 170 and a bimetal 187 installed on the base 140. And a leaf spring 181 for pressing the mount 173, and a support part and a fastening member 183 provided at the mount 173.

The bimetal 187 is the same member as the bimetal 87 shown in FIG. 4 and has the same structure and properties. One end of the bimetal 187 is clamped by a support provided on one side of the mount 173, and is fixed to the mount 173. In addition, the other end of the bimetal 187 is coupled to the fastening member 183 and fixed to the base 140.

One end of the leaf spring 181 is coupled to the upper portion of the base 140 by a screw, and the other end is in contact with the mount 173. The leaf spring 181 is elastically biased toward the mount 173 so that the guide surface 173a of the mount 173 is always in contact with the bottom surface 141a of the receiving portion 141. .

The support part includes a pair of protruding pins 185 provided to protrude from one side of the mount 173. A pair of the protruding pins 185 is provided, and one end of the bimetal 187 is sandwiched and clamped therebetween. The protruding pin 185 may be press-fitted or integrally formed on one side of the mount 173.

In the optical scanning unit according to the second embodiment of the present invention having the configuration as described above, the bimetal 187 is thermally expanded and deformed according to temperature change, and the mount 173 is centered on the one incident position P. The scan line L is directed to the same position while rotating to. Therefore, the optical photonic device according to the second embodiment has the same operation and effect as the case of the first embodiment described above with reference to FIG. 4, and thus description thereof will be omitted.

According to the optical scanning unit of the present invention as described above, it is possible to automatically adjust the position of the light source module according to the ambient temperature change to adjust the incident angle of the light incident at one incident position of the deflection disk. Therefore, even if the wavelength of the selected light changes due to the temperature change, the scanning lines diffracted and deflected on the deflection disc can be directed in the same direction, so that the scanning lines can be made constant at the correct position. And, this can lead to improved reliability and precision of the device.

Claims (7)

A base; A driving motor installed at the base and providing rotational force; A deflection disk installed in the drive motor, the deflection disk having a hologram pattern formed to diffractively deflect incident light, and forming a scan line by rotation; A light source module installed at the base so as to face one surface of the deflecting disk, wherein the light source module irradiates light to one incident position of the deflection disk; And a light source module position adjusting means having one end supported by the light source module and the other end fixed and having a bimetal that rotates the light source module while being deformed according to temperature change. The light source module is rotated with respect to the base with respect to one incidence position of the deflection disc by the bimetal, so that the center of the light scanned by the deflection disc is scanned at the same diffraction angle with respect to the deflection disc. Optical scanning unit characterized in that. The method of claim 1, wherein the base, It has a through hole through which the light emitted from the light source module passes, and is formed on the rear side and includes a guide for guiding the rotation of the light source module, The light source module, And a mount having a light source and a guide surface on which the light source is mounted and slidably positioned in the guide part. The method of claim 2, wherein the light source module position adjusting means, A support piece installed on the base and supporting the light source module such that the guide surface of the mount contacts the guide part of the base; A support part provided below the mount and supported by clamping one end of the bimetal; And a support bracket coupled to the base and supporting the other end of the bimetal. The method of claim 1, wherein the base, A receptacle formed from an upper surface thereof to receive the light source module slidably; The light source module, And a mount having a light source and a guide surface on which the light source is mounted, the guide surface being slidably in contact with the bottom surface of the receiving portion. The optical scanning unit of claim 4, wherein each of the bottom surface of the accommodation portion and the guide surface is a curved surface centered on one incidence position of the deflection disc. The method of claim 4 or 5, wherein the light source module position adjusting means, A leaf spring installed on the base and pressurizing the mount such that the guide surface of the mount contacts the bottom surface of the receiving portion; A support part provided at one side of the mount and supported by clamping one end of the bimetal; And a fastening member coupled to the base to fix the other end of the bimetal. The method of claim 6, wherein the support portion, A pair is provided at a predetermined interval so as to protrude from one side of the mount, the optical scanning unit, characterized in that it comprises a protruding pin is clamped by clamping one end of the bimetal.