KR20060121536A - Multi beam deflector by vibration - Google Patents

Abstract

A vibration type multi-beam deflector is provided to reduce the weight of deflective reflection mirrors and moment of inertia by removing an ineffective area from the deflective reflection mirrors. Two or more deflective reflection mirrors(115,116) include reflective sides for deflecting beams and vibrate about a rotary shaft at a constant frequency. A side frame(111) is for supporting the deflective reflection mirrors through the rotary shaft at the outside of the deflective reflection mirrors. A conductive pattern(119) having a loop shape is formed on one of first and second sides of the deflective reflection mirrors in order to form inductive magnetic field around the deflective reflection mirrors. A permanent magnet(135) is formed near the deflective reflection mirrors in order to supply the driving force to the deflective reflection mirrors by applying magnetic attraction and repulsive force to the deflective reflection mirrors.

Description

Multi beam deflector by vibration

1 is a schematic diagram of a laser color printer employing a polygon mirror as a beam deflector as one embodiment of the prior art.

Fig. 2 is a schematic diagram of a laser color printer employing a micromirror as a beam deflector as yet another embodiment of the prior art.

3 is a perspective view of a vibrating multi-beam deflector according to a first embodiment of the present invention.

4 is a cross-sectional view of the beam deflector shown in FIG. 3, taken along line IV-IV of FIG. 3.

5 is a perspective view of a vibrating multi-beam deflector according to a second embodiment of the present invention.

6 is a perspective view of a vibrating multi-beam deflector according to a third embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

101,102,103,104,301,302,303,304: unit light source

110,210,310: deflection plate 111,211,311: side frame

115,116,215,216,315,316,317,318: deflection reflecting mirror

119,219,319: driving conductive pattern 110,210,310: base substrate

130,230,330: Vibration Type Multi Beam Deflector

135,235,335: Micro permanent magnet

The present invention relates to a vibrating multi-beam deflector, and more particularly, to a beam deflector which is one of the main components of an optical scanning device for realizing a multi-color image by deflecting light beams emitted from a plurality of light sources simultaneously in a scanning direction. will be.

 In general, a laser scanning unit (LSU) is employed in devices such as laser printers, digital copiers, bar code readers, facsimile machines, and the like through the main scanning by the beam deflector and the sub scanning by the rotation of the exposed object. A latent image is formed on the optical surface. Particularly, in order to realize a multi-color image, a tandam type image forming apparatus having a plurality of exposed objects corresponding to each color component is used, and one type thereof is a color laser print.

1 shows a schematic structure of a color laser print. As shown, the light sources R _Y , R _M , R _C , R _k corresponding to each color component of Yellow, Magenta, Cyan, and Black are spaced at regular intervals. The light beams L _Y , L _M , L _C , L _K installed in parallel and emitted from each light source are incident to the first reflection mirror 61 with a predetermined beam pitch to each other, where the optical path is changed to The light is incident on the beam deflector 30 which is commonly formed for the plurality of light beams L _Y , L _M , L _C , L _K. The beam deflector 30 includes a drive source 31 which rotates at a high speed about the rotation axis C and a polygon mirror 33 which deflects the incident light beam in the main scanning direction while rotating at constant speed by the drive source 31. A plurality of reflective surfaces 33a are formed along the outer surface of the polygon mirror 33 formed in a polygonal structure. By the polygon mirror 33, the respective light beams L _Y , L _M , L _C , L _K are deflected together, and the deflected light beams L _Y , L _M , L _C , L _K are directed in the sub-scanning direction. The optical path is converted by the plurality of aligned second reflecting mirrors 62 and is incident on the optical scanning lens 50, also called a f-theta lens. The optical scanning lens 50 functions to condense the deflected light beam to be imaged on the scanning line of the targets D _Y , D _M , D _C , D _K. The light beams L _Y , L _M , L _C , L _K converted through the optical scanning lens 50 into the convergent light form are changed in the optical paths by the third reflecting mirrors 63, so that each of the different exposure targets ( D _Y , D _M , D _C , D _K ). That is, the light beams (L _Y , L _M , L _C , L _K ) corresponding to each color component of Yellow, Magenta, Cyan, and Black are transmitted by different light paths. In addition, an image is formed on each of the exposed objects D _Y , D _M , D _C , and D _K to form a predetermined latent image.

Here, the polygon mirror as the beam deflector 30 is formed universally with respect to the plurality of independently emitted light beams L _Y , L _M , L _C , L _K , thereby simultaneously reflecting the incident light beams with a beam pitch. For this purpose, it should have a large area of reflection including margin. As the polygon mirror is increased in size, the moment of inertia increases, and the driving source for driving the polygon mirror must be enlarged to provide a large power, and this increase in driving load acts as a limiting factor for the vibration speed. In this case, in order to increase the rotational speed of the polygon mirror, a pneumatic bearing suitable for high-speed rotation and a driving IC for high power are required. Along with this problem, a constant flow field is formed around the polygon mirror which is rotated at constant velocity, so that the reflection surface of the polygon mirror is contaminated by foreign matters such as dust. In particular, when the reflection area is increased, the reflection surface contamination. Due to the degradation of the light efficiency and thereby the degradation of the image quality is intensified, and shorten the life of the product.

On the other hand, instead of the polygon mirror of the type that is rotationally driven as the beam deflector, a micro mirror 10 which vibrates at a predetermined frequency as shown in FIG. 2 may be used. For reference, in the drawings, the micro mirror 10 is shown in an enlarged form for convenience of description. As can be seen in the figure, the light source units 1, 2 for generating and emitting light beams are arranged in parallel, and each light source unit 1, 2 is formed of a so-called one can-two beam type. . That is, in each light source unit (1, 2), two different unit light sources (R _Y , R _M : R _C , R _K ), for example, laser diodes are packaged into a single optical component in a pair. At this time, the micromirror 10 should have a sufficient reflecting area to simultaneously deflect the light beams L _Y , L _M , L _C , L _K incident with a constant beam pitch with respect to each other. The light beams incident on the micromirror 10 are deflected in the scanning direction by the reflecting surface 15 oscillating about the rotation axis C. As shown in FIG. The deflected light beams L _Y , L _M , L _C , L _K branch through different optical paths while passing through the scanning optical lens 70 and the first to third reflecting mirrors 81, 82, and 83, respectively. Since an image should be formed on the exposed object D _Y , D _M , D _C , D _K , a certain degree of beam pitch must be maintained between the respective light beams L _Y , L _M , L _C , L _K. In the micromirror 10, a large portion of the invalid area A which does not perform the deflection function of the light beam is present, and since the invalid area is integrally formed, the moment of inertia of the micromirror 10 increases. As is known, in the micromirror 10 requiring high-speed vibration, the moment of inertia of the micromirror 10 serves as a limiting factor in improving the vibration speed. Therefore, there is a need to remove the inefficient reflection surface to reduce the weight of the micromirror 10 and to improve the vibration angle and vibration frequency which are closely related to the scanning speed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems and other problems, and it is possible to reduce the moment of inertia by eliminating the useless reflection area, thereby improving the vibration frequency and the vibration speed of the vibration type multi-beam. It is an object to provide a deflector.

In order to achieve the above object, the vibrating multi-beam deflector according to the present invention is a vibrating multi-beam deflector for deflecting at least two or more light beams incident with a predetermined beam pitch in the scanning direction, the reflection surface for deflecting the light beams At least two deflection reflecting mirrors formed at predetermined intervals from each other, a side frame supporting the deflection reflecting mirrors through the rotating shaft outside the deflecting reflecting mirrors; A driving conductive pattern formed in a loop shape on at least one of first and second surfaces opposite to each other of the deflection reflecting mirror, and in which current is communicated to form an induction magnetic field around the deflection reflecting mirror; and the deflection It is formed adjacent to the reflection mirror, by the conductive pattern for driving Also interact with the magnetic field, while the action of magnetic attraction and repulsion to the deflection by the reflecting mirror includes a permanent magnet providing a driving force to the deflecting reflection mirrors.

The deflection reflecting mirrors may be supported by rotational shafts formed independently from each other by the side frame. Alternatively, the deflective reflection mirrors may be supported together by a common pivot formed across the deflection reflection mirrors.

In one embodiment of the present invention, the driving conductive pattern forms a commonly formed loop while sequentially passing through the deflection reflecting mirrors, and an electrical signal is applied to the driving conductive pattern by the same controller.

As another embodiment of the present invention, the driving conductive pattern forms a plurality of loops independently formed for each deflection reflecting mirror, and electrical signals are provided by controllers formed separately in each loop of the composition conductive pattern. Is approved.

Hereinafter, with reference to the accompanying drawings, it will be described in detail preferred embodiments of the present invention. 3 and 4 show a vibrating multi-beam deflector according to a first embodiment of the present invention. FIG. 3 is a perspective view of the beam deflector, and FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 3. Is shown. The illustrated multi-beam multi-beam deflector 130 includes an upper deflection plate 110 and a lower base substrate 120 that are joined to face each other. Two deflection reflecting mirrors 115 and 116 are formed on the inner side of the deflection plate 110 and reflecting layers M are formed on the outer surface thereof, and a side frame having a rectangular frame structure is formed on the outer side of the deflecting reflecting mirrors 115 and 116. 111 is formed. The first deflection reflecting mirror 115, the second deflecting reflecting mirror 116 and the side frame 111 are interconnected by a narrowly formed pivot shaft 113, whereby the deflecting reflecting mirrors 115, 116 are side The frame 113 is supported so as to enable reciprocating vibration (oscillates about the C axis in the drawing) in the clockwise and counterclockwise directions. That is, the first deflection reflecting mirror 115 and the second deflection reflecting mirror 116 are supported on the same pivot shaft 113 and oscillated about the same. Thus, the first deflecting reflecting mirror 115 and the second deflecting mirror As the reflection mirror 116 is mutually coupled by the same pivot shaft 113, they are rotated at the same vibration angle. The deflection reflector 110, including the deflection reflecting mirrors 115 and 116, the side frame 111, and the pivot shaft 113, is preferably formed integrally with a single crystal silicon material. Fatigue failure of the coaxial 113 can be prevented.

The light beams emitted from the first light source unit 108 and the second light source unit 109 arranged in parallel with a predetermined distance between the first deflection reflecting mirror 115 and the second deflecting reflecting mirror 116 ( L1, L2, L3, and L4 are incident. Here, two different light sources 101, 102: 103, 104 are packaged in pairs in each light source unit 108, 109. The light beams of L1 and L2 emitted from the first light source unit 108 are reflected by the first deflective reflection mirror 115 which reciprocates and are deflected in the main scanning direction. Although not shown, the deflected light beam is disposed on the optical path. The plurality of reflecting mirrors guide light onto different subjects. Similarly, the light beams of L3 and L4 emitted from the second light source unit 109 are deflected by the second deflection reflecting mirror 116 which vibrates at a predetermined frequency, and the deflecting beam is a plurality of reflecting mirrors (not shown). The optical path is changed by) to guide light onto different subjects.

The first deflection reflecting mirror 115 and the second deflecting reflecting mirror 116 are formed to simultaneously deflect the light beams irradiated from two or more light sources. For example, when two light beams of L1 and L2 are incident into the first deflection reflector 115 with the beam pitch P1 therebetween, the deflection reflector 115 may deflect these light beams L1 and L2 simultaneously. As such, the area of the deflection reflecting mirror 115 is determined in consideration of the beam pitch P1 or the beam diameter of the light. Likewise, when two different light beams L3 and L4 spaced by the beam pitch P2 are incident on the second deflective reflector 116, the second deflective reflector 116 causes them to enter the single deflective reflector 116. It is designed to have a sufficient reflecting area to simultaneously scan the deflection. However, it is preferable that the first deflection reflecting mirror 115 and the second deflecting reflecting mirror 116 do not include an invalid reflecting surface that does not perform a deflection function in order to minimize the inertia. That is, the light beams L1, L2, L3, L4 emitted from different light source units 108, 109 are incident with a relatively long beam pitch d with respect to each other. In this embodiment, this beam pitch d Are removed so that the useless portions (which are the portions corresponding to the reference numeral A in the prior art shown in FIG. 2) are not included in the deflection reflecting mirrors 115 and 116, so that the openings G are formed. That is, by removing the invalid area of the deflection reflecting mirror that does not perform the reflection function to reduce the weight of the deflection reflecting mirror, vibration characteristics such as vibration frequency and vibration angle can be improved.

Reflective layer (M) formed on the outer surface of the deflection reflector (115,116) may be made of a thin layer of aluminum (Al) or silver (Ag) component, these reflecting layer (M) is formed by being deposited on the deflection reflecting mirror (115,116) surface Can be. A driving conductive pattern 119 is formed on the bottoms of the deflection reflecting mirrors 115 and 116 opposite to the reflective layer M. More specifically, the driving conductive pattern 119 is formed in a loop shape surrounding the inside of the deflection reflecting mirrors 115 and 116. The driving conductive pattern 119 may be formed on any one surface of the main surface forming the upper and lower surfaces of the deflection reflecting mirrors 115 and 116, and thus may be formed on the surface on which the reflective layer M is formed.

The driving conductive pattern 119 shown forms a loop via the first deflection reflecting mirror 115 and the second deflecting reflecting mirror 116. The driving conductive pattern 119 receives an AC voltage of a predetermined frequency by the high frequency voltage generator 141 connected to the end thereof, and the high frequency voltage generator 141 is controlled by the controller 145. As a voltage is applied to the driving conductive pattern 119, an induction magnetic field is formed around the deflection reflection mirrors 115 and 116. The polarity of the applied voltage is inverted at a high frequency, and the polarity of the induction magnetic field is inverted at the same period. . The induced magnetic field provides driving force to the deflection reflecting mirrors 115 and 116 by interaction with the permanent magnet 135, which will be described later. In this case, the driving conductive pattern 119 forms a common loop while passing through the first deflection reflecting mirror 115 and the second deflecting reflecting mirror 116 together, and thus the same driving force is applied to the deflecting reflecting mirrors 115 and 116. This is provided.

Permanent magnets 135 are formed in the side frames 111 facing the deflection reflecting mirrors 115 and 116. That is, the predetermined region of the side frame 111 is etched and the micro permanent magnet 135 is inserted therein. It is preferable that the permanent magnets 135 disposed in pairs on both sides with the deflection reflecting mirrors 115 and 116 interposed therebetween have different polarities. The permanent magnet 135 interacts with the induced magnetic field formed by the driving conductive pattern 119 and exerts a magnetic attraction force or a repulsive force on the ends of the opposing deflection reflecting mirrors 115 and 116. The reflecting mirrors 115 and 116 are rotated about the pivot shaft 113 by receiving a rotation moment in a clockwise or counterclockwise direction. When a predetermined AC voltage whose polarity is periodically changed is applied to the driving conductive pattern 119, the deflection reflecting mirrors 115 and 116 fluctuate with a constant period as the current direction communicating the conductive pattern 119 changes. do. Accordingly, by applying a predetermined AC voltage corresponding to the resonant frequencies of the deflection reflection mirrors 115 and 116, for example, by applying an AC voltage having a frequency equal to the resonant frequency of the deflection reflection mirrors 115 and 116, the deflection reflection mirror 115 and 116 vibrate in a resonance state with a large vibration angle.

The deflection plate 110 is supported on the base substrate 120, and the base substrate 120 is formed of an insulating material to be electrically separated from the deflection plate 110. The base substrate 120 has a rectangular rim structure, whereby a predetermined space portion 120 ′ is formed below the base reflector 120 so that rocking motions of the deflection reflecting mirrors 115 and 116 are not interfered with.

5 shows a resonant multi-beam deflector 230 according to a second embodiment of the present invention. Referring to the drawings, the beam deflector 230 of the present embodiment includes a deflection plate 210 and a base substrate 220 joined to face up and down. The deflection plate 210 includes a side frame 211 that forms a skeleton from the outside and at least two deflective reflection mirrors 215 and 216 slidably supported inside the side frame 211, for example, as shown in FIG. In the beam deflector 230, a first deflective reflection mirror 215 and a second deflection reflection mirror 216 are formed. Here, the first deflection reflecting mirror 215 and the second deflecting reflecting mirror 216 are mechanically separated from each other by the separating portion 211a of the side frame 211 formed between them 215 and 216, each deflection The reflection mirrors 215 and 216 are supported by rotational axes independent from each other, that is, the first rotational axis 213 and the second rotational axis 214. As a result, the first and second deflective reflection mirrors 215 and 216 may be independently oscillated without affecting each other.

The first conductive pattern 218 for driving in a loop shape surrounding the inner side of the deflective reflecting mirror 215 is formed on the bottom of the first deflective reflecting mirror 215, and the end of the conductive reflecting mirror 215 has a first controller. And a first high frequency voltage generator 241 under the control of 245. Similarly, a loop-shaped second driving pattern 219 is formed on the bottom of the second deflection reflecting mirror 216, and an end of the conductive pattern 219 is driven by the second controller 246. A second high frequency voltage generator 242 is connected. Thus, different conductive patterns 218 and 219 are formed, and the first deflection reflector 215 and the second deflection reflector 216 controlled by different controllers 245 and 246 may be driven independently of each other. In other words, they can be driven at different vibration frequencies or vibration angles.

However, when these deflective reflection mirrors 215 and 216 deflect light beams corresponding to four color components of yellow, magenta, cyan and black according to a conventional driving method, the same vibration frequency In many cases, the conductive patterns formed on the first deflection reflector and the second deflection reflector may be commonly connected to the same high frequency voltage generator and controller. In addition, the micro permanent magnet 235 is inserted into the side frame 211 facing the deflection reflecting mirrors 215 and 216 as described in the first embodiment.

6 shows a vibrating multi-beam deflector 330 according to a third embodiment of the present invention. The vibrating multi-beam deflector 330 includes a deflection plate 310 and a base substrate 320 coupled to face each other. The deflection plate 310 is integrally formed with a side frame 311 forming an outline in a substantially rectangular edge shape and a plurality of deflection reflecting mirrors 315, 316, 317, and 318 formed inside the side frame 311.

The beam deflector 330 of the present embodiment has a constant spacing corresponding to a so-called one can-one beam method, that is, a light source structure in which a single light beam is emitted from the unit light sources 301, 302, 303 and 304 packaged independently of each other. A plurality of deflective reflection mirrors (315, 316, 317, 318) formed to be separated from each other. Four deflective reflection mirrors 315, 316, 317 and 318 are formed in the illustrated beam deflector, and these deflective reflection mirrors 315, 316, 317 and 318 reflect light beams L1, L2, L3 and L4 emitted from independent light sources 301, 302, 303 and 304. Deflect in the main scanning direction. For example, different light beams of L1, L2, L3, and L4 are incident on the deflective reflection mirrors 315, 316, 317, and 318, which may be incident on the deflective reflection mirrors 315, 316, 317, and 318 with a constant beam pitch P therebetween. . That is, the predetermined area between the deflection reflecting mirrors is removed so that the invalid area corresponding to the beam pitch P and the light beam is not incident is not included in the deflection reflecting mirrors 315, 316, 317 and 318 so that the opening G is formed. In this way, the moment of inertia of the deflection reflecting mirror is reduced, and the driving characteristics of the deflecting reflecting mirror including the vibration speed and the vibration frequency are substantially the same as described in the first embodiment.

The first to fourth deflection reflecting mirrors 315, 316, 317 and 318 are connected by a common pivot 313 which supports them mutually, whereby they are mechanically coupled to each other. The driving conductive pattern 319 which forms a magnetic field in the deflection reflecting mirrors 315, 316, 317 and 318 forms one single loop via the deflection reflecting mirrors 315, 316, 317 and 318 sequentially. The driving conductive pattern 319 is supplied with a predetermined alternating voltage by the high frequency voltage generator 341 connected to the end thereof, and an induction magnetic field whose polarity is inverted periodically is formed by the alternating voltage. On the other hand, the high frequency voltage generator 341 generates an AC voltage having a predetermined frequency based on the output signal of the controller 345. The magnetic field induced around the deflection reflectors 315, 316, 317, 318 provides driving force to the deflection reflectors 315, 316, 317, 318 through interaction with the permanent magnet 335 arranged to face the deflection reflectors 315, 316, 317, 318. The oscillating oscillation is performed clockwise and counterclockwise about the shared rotation shaft 313.

On the other hand, in the drawings attached to this specification as a light source structure for emitting light to the beam deflector, a point light source having a point-shaped light emitting unit is shown, the present invention is not limited to such a light source structure, for example, VCSEL It can be easily understood by those skilled in the art to which the present invention can be applied even in the case of a surface light source having a light emitting part such as a vertical cavity surface emitting laser (Vertial Cavity Surface Emitting Laser).

According to the vibration type multi-beam deflector of the present invention, in the multi-beam deflector deflecting a plurality of light beams in the scanning direction, the deflection reflector is lighter by removing the invalid area which does not perform the deflection function from the deflective reflector, thereby reducing the inertia moment. It is possible to reduce the vibration frequency and the vibration angle of the beam deflector to improve the optical scanning speed, as well as to improve the driving efficiency of the beam deflector, thereby realizing a low power optical scanning device.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (5)

An oscillating multi-beam deflector for deflecting at least two or more light beams incident with a predetermined beam pitch in a scanning direction, At least two deflection reflecting mirrors having a reflecting surface for deflecting the light beams and oscillating oscillating about a rotational axis at a constant frequency, the at least two deflecting reflecting mirrors formed at predetermined intervals from each other; A side frame for supporting the deflective reflection mirrors through the rotational shaft outside the deflective reflection mirrors; A driving conductive pattern formed in a loop shape on at least one of first and second surfaces opposite to each other of the deflective reflection mirror, and in which current is communicated to form an induction magnetic field around the deflection reflection mirror; And A permanent magnet which is formed adjacent to the deflective reflection mirror and provides a driving force to the deflective reflection mirror by applying magnetic attraction and repulsive force to the deflection reflection mirror while interacting with a magnetic field induced by the driving conductive pattern; Vibration type multi-beam deflector comprising a. The method of claim 1, The deflection reflecting mirrors, the vibration type multi-beam deflector, characterized in that each of which is supported by a rotation shaft formed separately from each other by the side frame. The method of claim 1, And said deflective reflecting mirrors are supported together by a common pivot formed across said deflecting reflecting mirrors. The method of claim 1, The driving conductive pattern forms a loop commonly formed while sequentially passing through the deflection reflecting mirrors, and an electrical signal is applied to the driving conductive pattern by the same controller. The method of claim 1, The driving conductive pattern forms a plurality of loops formed independently for each deflection reflecting mirror, and each of the loops of the conductive pattern includes an electrical signal applied by a controller formed separately. Beam deflector.

Images