JP4484508B2 - Laser scanning device - Google Patents

Description

  The present invention relates to a laser scanning device that generates lines in both X and Y directions using two semiconductor laser light sources and one polygon mirror, and allows scanning on the same image plane with both lines.

2. Description of the Related Art A line generator that uses a semiconductor laser as a light source and scans an image plane as a light beam deflected by a polygon mirror in the X or Y direction is used in various fields. One example is a plotter for printing. This is to create various printing blocks and printed circuit board masters, etc., by installing a sensitive material at the image plane position, and projecting X or Y direction lines with light generated from the plotter, A desired image is created. A reading device called a scanner is also known. In this method, light in the X and Y directions is applied to the surface of an arbitrary object and the like, and the shape of the object surface is read by scanning the light. Another example is an inking tool used when assembling various members. This is used for registering the members to be assembled in the vertical direction and the horizontal direction, and uses the X or Y direction line of light generated from the line generator as a guide ink.
One of the problems with such an apparatus is a means for generating lines in the X or Y direction. As described above, a laser is generally used as a light source, and the beam is deflected by a polygon mirror to be generated as a line in the X or Y direction. There is also known a multi-beam method in which beams from two laser light sources are applied to separate reflecting surfaces of a single polygon mirror to simultaneously generate two lines in either the X or Y direction. Yes. However, in either case, the line obtained on the imaging plane is only in one direction of X or Y, and it is difficult to obtain lines in both the X and Y directions from a single polygon mirror almost simultaneously on the same imaging plane. there were. For this reason, a polygon mirror dedicated to the X direction and a polygon mirror dedicated to the Y direction are provided separately, and a laser light source is associated with each to reflect and deflect the beam to obtain a line in a predetermined direction. Therefore, two identical members had to be prepared, and the entire apparatus became large and expensive. Another problem is the inefficiency of line generation. This employs a system in which a light beam from a laser light source is applied to one reflecting surface of a polygon mirror, and one line in the main scanning direction is projected onto the imaging surface by deflection of the reflected light beam obtained by the rotation. Because. Therefore, only one line can be generated on one reflecting surface. Also, the second line could not be projected to a new position unless the image plane was moved in the sub-scanning direction.
JP 2000-121983

  In order to solve the above problems, the present invention is a simple, small, and inexpensive laser having a structure in which lines in both the X and Y directions are generated almost simultaneously using a single polygon mirror and can scan on the same image plane. An object is to provide a scanning device. It is another object of the present invention to improve the generation efficiency of lines by allowing a plurality of lines to be generated on each reflecting surface constituting the polygon mirror.

In order to achieve the above object, according to the present invention, a light beam from a first semiconductor laser light source is applied to a polygon mirror having n reflecting surfaces, and the reflected light is directed to an imaging surface via a shape converting unit. A first optical unit that scans the imaging surface in the main scanning direction according to the rotation of the mirror, and a light beam from the second semiconductor laser light source is applied to the polygon mirror, and the reflected light passes through the shape converting unit and the direction changing unit. The second optical unit that scans the imaging surface in the sub-scanning direction according to the rotation of the polygon mirror and the first and second optical units are installed in the first and second optical units, respectively. A shape converting unit that receives reflected light moving in the scanning direction and converts the reflected light into a line-shaped reflected light with the light spot of the reflected light oriented in the sub-scanning direction, and is installed in the second optical unit. Receives line-shaped reflected light in the sub-scanning direction and The reflected light and a direction changing section for diverting the reflected light in the main scanning direction of orientation and the line shape, the upper image forming surface by the reflection light of the line shape of the sub-scanning direction of the orientation by the first optical unit Scan in the main scanning direction, scan in the sub-scanning direction with the line-shaped reflected light in the main scanning direction by the second optical unit, and scan the same imaging surface with the two line-shaped reflected light It is characterized by scanning in the main and sub directions .
According to a second aspect of the present invention, in the laser scanning device according to the first aspect, the light beams from the first and second semiconductor laser light sources are applied to one polygon mirror, and each reflected light moves in the main scanning direction. A scanning lens that directs to the primary imaging plane, an objective lens that is installed on the same optical axis as both scanning lenses and that directs reflected light from both primary imaging planes to the same imaging plane, and between the scanning lens and the objective lens A shape conversion unit using a rod lens that receives reflected light moving in the main scanning direction from the primary imaging plane and converts the reflected light point into a line-shaped reflected light in the sub-scanning direction. The first and second optical units are provided .
According to a third aspect of the present invention, in the laser scanning device according to the first aspect, the first mirror is disposed between the primary imaging surface and the shape converting unit of the second optical unit, and is disposed between the objective lens and the imaging surface. The first mirror receives reflected light that moves in the main scanning direction through the primary imaging plane, and changes the direction so that the traveling direction of the central optical axis beam is parallel to the imaging plane. The second mirror receives the reflected light from the first mirror, changes its direction so that the traveling direction of the central optical axis light beam is orthogonal to the imaging plane, and reflects the reflected light moving in the main scanning direction reflected by the first mirror. Is turned into reflected light that is reflected by the second mirror and moves in the sub-scanning direction, and the direction-changing unit is configured to direct the converted reflected light toward the imaging surface .
According to a fourth aspect of the present invention, in the laser scanning device according to the first or second aspect, the reflected light from the polygon mirror that has passed through the first and second optical section through the shape converting section is received, and the reflected light is transmitted to the rotation angle of the polygon mirror. The image-forming position correcting means composed of an fθ lens that is directed to the image-forming surface position proportional to θ is provided in the first and second optical units .
According to the invention of claim 5, a light beam from the first semiconductor laser light source is applied to a polygon mirror having n reflecting surfaces, and the reflected light is directed to an image forming surface via a shape converting unit. The first optical unit that scans the imaging surface in the main scanning direction according to the rotation of the light source, and the light beam from the second semiconductor laser light source is applied to the polygon mirror, and the reflected light passes from the direction conversion unit to the shape conversion unit. The second optical unit that scans the imaging surface in the sub-scanning direction according to the rotation of the polygon mirror and the second optical unit that is installed in the first optical unit and moves in the main scanning direction from the polygon mirror A shape conversion unit that receives the reflected light and converts the reflected light into a reflected light having a shape in the direction of the sub-scanning direction, and a second optical unit that is installed in the main scanning direction from the polygon mirror. The moving reflected light is received by the first mirror, The traveling direction of the central optical axis of the light beam is directed to the second mirror so that the traveling direction of the central optical axis is parallel to the imaging surface, the reflected light is received by the second mirror, and the traveling direction of the central optical axis beam is orthogonal to the imaging surface. The direction change unit that changes the direction to be reflected and moves toward the image plane as reflected light that moves in the sub-scanning direction, and the line-shaped reflected light that has the light spot of the reflected light received from the direction change unit in the main scanning direction And a shape conversion unit for converting into a main scanning direction by scanning the imaging surface with a line-shaped reflected light oriented in the sub-scanning direction by the first optical unit, and in the main scanning direction by the second optical unit. The image forming surface is scanned in the sub-scanning direction with the line-shaped reflected light in the direction, and the same image forming surface is scanned in the main and sub-directions with the two line-shaped reflected light .
According to a sixth aspect of the invention, in the laser scanning device according to the first and fifth aspects , the rod lens that receives the reflected light from the polygon mirror and converts the reflected light spot into a line-shaped reflected light is curved. The shape conversion unit is configured so that, when reflected light passes through the curved rod lens, the angle is such that the passing light is perpendicularly incident on the central axis of the rod lens .

In the present invention, a light beam from two laser light sources is applied to one polygon mirror having n reflection surfaces, and the image formation surface is a line that scans the one reflected light beam in the main scanning direction via the first optical unit. The other reflected light beam is directed to the image plane as a line that scans in the sub-scanning direction via the second optical unit. For this reason, both optical units contain a shape conversion unit, and the light spot of the light beam traveling toward the imaging surface passes through this conversion unit, so that the light is formed into a line shape (Y-type line) once oriented in the sub-scanning direction. The point is converted, and the Y-type line oriented in the sub-scanning direction is moved in the main scanning direction in the first optical unit. The second optical unit is provided with a light beam direction changing unit, and when receiving a Y-shaped line whose shape is changed in the sub-scanning direction from the shape converting unit, the Y-type line is again set as the direction of the main scanning direction. The converted X-type line is moved in the sub-scanning direction. Thereby, in the second optical unit, the reflected light beam spot from the polygon mirror is first converted into a Y-type line oriented in the sub-scanning direction by the shape converting unit, and then the X-type oriented in the main scanning direction by the direction changing unit. Since it is converted into a line, the rotation of the polygon mirror is the scanning in the sub-scanning direction on the image plane.
With such a configuration, it is possible to efficiently perform scanning in both the main and sub directions at the same time on the image plane according to the angle of one reflecting surface by only rotating one polygon mirror. Conventionally, the light spot deflected by one reflecting surface of the polygon mirror moves in the main scanning direction and projects one line, so that an arbitrary number of lines are generated on one reflecting surface of the polygon mirror. The system can be changed to a method of generating lines, and the efficiency of line generation can be improved. Further, the movable part of the entire apparatus is only a polygon mirror, and the first and second optical parts and the shape changing part and the direction changing part accommodated in the first and second optical parts can all be fixed. As a result, it is possible to provide a device which is simple in structure as a whole, and which is small and inexpensive.

  A laser scanning apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram for explaining a laser scanning device according to the present invention. In the figure, P represents a scanning optical system, and is composed of first and second semiconductor laser light sources 1 and 2, a polygon mirror 3, first and second optical units 4 and 5, and the like. The beam 6 from the first semiconductor laser light source 1 is reflected by an arbitrary surface of the polygon mirror 3 having n reflection surfaces, for example, the n1 surface, and forms an image while passing through the first optical unit 4 according to the reflection angle. The surface 7 is scanned. Although this scanning is called main scanning, the polygon mirror 3 is rotated by a polygon motor 9 controlled by the control unit 8. Before reaching the imaging plane 7, the beam 6 from the first light source 1 passes through a first optical unit 4, which will be described in detail later, and a shape converting unit accommodated therein. As a result, the light spot of the beam 6 moving in the main scanning direction has a shape of a line 11 (hereinafter referred to as a Y-type line) converted into the direction of the sub-scanning direction orthogonal to it. The converted Y-type line 11 moves in the X direction (main scanning) indicated by the arrow 10 on the imaging surface 7 in accordance with the angle of the reflection surface n1 due to the rotation of the polygon mirror 3. The control unit 8 is connected to an input unit 12 such as a keyboard or an MD, and commands operations such as the light emission timings of the first laser light source 1 and the second laser light source 2, the rotation angle of the polygon motor 9, and the number of rotations. Manage and control. The beam 13 from the second laser light source 2 is reflected by an arbitrary surface of the polygon mirror 3, for example, the n2 surface following the n1 surface, and travels toward the imaging surface 7 through the second optical unit 5. Details of the inside of the second optical unit 5 will be described later in the same manner as described above, but the shape conversion unit is accommodated in the same manner as the first optical unit 4, and the light spot of the beam 13 is the same as described above by passing therethrough. Are converted into Y-type lines. Then, the converted Y-type line passes through the direction changing part accommodated in the second optical part, and its traveling direction is changed by 90 degrees to become the X-type direction (direction in the main scanning direction) . It is converted to line 15 (hereinafter referred to as X-type line). As the polygon mirror rotates and the angle of the reflection surface n2 changes, the X-type line 15 scans the imaging surface 7 in the sub-scanning direction 14 according to the deflection angle. That is, the reflected light flux that moves in the main scanning direction received from the polygon mirror 3 by passing through the direction changing portion is changed in direction from the Y-type line to the X-type line, and moves on the imaging surface in the sub-scanning direction. I will do it.
By this movement, the Y-type line 11 by the reflected light beam from the n1 surface and the X-type line 15 by the reflected light beam from the n2 surface are simultaneously projected on the imaging plane 7. When the polygon mirror 3 rotates and the reflection and deflection of the light beam by the n1 surface is completed, the n1 surface is positioned at a position facing the second laser light source 2, and a new reflection surface is positioned at the first laser light source 1. If the same operation as described above is performed using these two new reflecting surfaces, the X-type line 15 and the Y-type line 11 can be projected onto the image plane 7 again.

FIG. 2 is an explanatory diagram showing a state when the light beam that has passed through the first optical unit 4 scans and moves in the main scanning direction 10 on the imaging surface 7 as a Y-type line 11. In FIG. 2A, the Y-type line 11 sequentially moves in the main scanning direction as 11-1, 11-2, 11-3,... 7 The top is scanned. In other words, conventional laser scanning devices have generated a light beam reflected by one reflecting surface of a polygon mirror as one line that travels in the main scanning direction. In the present invention, the reflected light beam from the polygon mirror 3 moving in the main scanning direction is converted into the Y-type line 11 as shown in FIG. 2A by passing through the shape conversion unit, and this Y-type line is converted into the deflection angle of the n1 reflecting surface. Are moved in the main scanning direction, and the lines 11-1, 11-2,... Are continuously projected. The projected speed is determined by the rotational speed of the polygon mirror 3, but the first light source 1 emits light only when the angle of the reflecting surface n1 with respect to the beam 6 becomes the angle commanded by the input unit 12. Then, for example, the line 11n can be connected to the designated position on the imaging plane 7. Since the X-type line 15 is exactly the same, its description is omitted.
The timing of starting the main scanning in the direction of the arrow 10 by the Y-type line 11 and the sub-scanning by the X-type line 15 may be performed simultaneously on the n1 plane and the n2 plane as described above, but the polygon mirror 3 While the deflection operation by the n1 surface is being performed, the generation operation of the X-type line 15 by the n2 surface and the second optical unit 15 can be stopped. Even in this case, since the X-type line 15 is scanned immediately after the Y-type line 11 is scanned, both the X and Y lines 11 and 15 can be obtained almost simultaneously. Moreover, since the scanning times of the X and Y type lines can be regarded as the same, the generation of both the X and Y lines can be managed in the same time. Then, if the Y-type line 11 scans the region 16 in FIG. 2 by the rotation of one reflecting surface n1 of the polygon mirror 3, the imaging surface 7 is moved in the direction opposite to the arrow 10 to move the n3 reflecting surface, or The region 17 in the figure can be covered with the n1 reflecting surface of the second rotation. When the image plane 7 is not moved, the same region 16 is naturally scanned repeatedly. Accordingly, by making the beams 6 and 13 of the light sources 1 and 2 visible, and selecting the rotation speed and rotation angle of the mirror 3, the X and Y type lines 11 and 15 can be seen. It can be used as a line for inking during assembly processing. Note that a laser beam origin position detector is required to correctly determine the position at which the first Y-type line 11-1 forms an image in FIG. 2A. The same applies to the X-type line 15 formed by the second optical unit 5.

FIG. 3 shows the inside of the first optical unit 4, where A is a plan view, B is a front view, and C is a perspective view with a part omitted. In the figure, reference numeral 20 denotes a scanning lens which receives a reflected light beam from the polygon mirror 3 and forms an image of the light spot on the primary imaging surface 21. Reference numeral 22 denotes a shape conversion unit which is composed of a lot lens, a cylinder lens or the like, and is arranged so as to receive a light beam in the main scanning direction by the polygon mirror 3. An objective lens 23 is arranged on the optical axis of the scanning lens 20 and projects an image of the primary imaging surface 21 onto the imaging surface 7 through the shape converting unit 22. When the polygon mirror 3 rotates in the direction of the arrow in the figure, the beam 6 from the first light source 1 passes through the scanning lens 20 surface in accordance with the reflection angle of the arbitrary reflection surface n1. FIG. A shows the time when the reflected light beam is on three points of the passing positions 24a, 24b, and 24c of the scanning lens 20, and images are formed on the positions 25a, 25b, and 25c on the primary imaging surface 21, respectively. The imaged light spot is converted into the shape of the Y-shaped line 11 by the shape converting unit 22 and projected onto the image forming surface 7 by the objective lens 23. In FIG. A, three images of the light spots 25a to 25c are respectively shown as 26a to 26c on the imaging plane 7, and in FIG. B, the image of 26b by the light spot 25b on the central optical axis of the primary imaging plane 21 is represented as Y It is shown as a mold line 11. FIG. C shows a state in which the light spot 24b on the optical axis is projected onto the image plane 7 after being transformed into the Y-type line 11b by the shape transformation unit 22 as in FIG. In FIG. C, the objective lens 23 is omitted, but as the reflecting surface n1 of the polygon mirror 3 rotates, the reflected light beam scans on the scanning lens 20 in the directions 24a to 24c, and on the image plane 7. Then, scanning is performed in the direction of 26a to 26c, that is, in the direction of the arrow 10 in FIG. Since the scanning in the direction of the arrow 10 is scanning in the main scanning direction, the Y-type lines 11-1, 11-2,... Sequentially move on the image plane 7 as shown in FIG.
As described above, the first optical unit 4 receives the reflected light flux moving in the main scanning direction from the polygon mirror 3 and converts the shape of each light spot into the Y-type line 11. The image plane 7 is scanned in the main scanning direction.

4, 5, and 6 show the inside of the second optical unit 5. FIG. 4A is a plan view, B is a front view, FIG. 5A is a right side view, B is an explanatory view, and FIG. It is an explanatory perspective view omitted and shown. In the figure, reference numeral 27 denotes a scanning lens that receives the light beam R1 reflected by the n2 surface of the polygon mirror 3, and forms an image of the light spot on the primary imaging surface 28. The distance L1 (FIG. 4A) from the reflection point of the polygon mirror 3 to the scanning lens 27 and the distance L2 from the scanning lens 27 to the primary imaging plane 28 are the polygon mirror 3 of the first optical unit 4, the scanning lens 20, and the primary connection. It is the same as that of the image plane 21. Reference numerals 29 and 30 denote first and second mirrors, which constitute a direction changing section 31 that changes the traveling direction of the light beam. When the first mirror 29 receives the reflected light beam R1 from the polygon mirror 3 as shown in FIG. 5A, the first mirror 29 is installed at an angle of 45 degrees so as to change the traveling direction of the light beam to 90 degrees vertical direction. The traveling direction of the central optical axis is directed to a plane parallel to the imaging plane 7. Reference numeral 32 denotes a shape conversion unit, which is composed of a lot lens or a cylinder lens, like the shape conversion unit 22 of the first optical unit 4. The shape conversion unit 32 is installed below the first mirror 29 and in parallel with the mirror so that the light beam which is changed in direction by the first mirror 29 and becomes a reflected light beam R2 can enter. An objective lens 33 is disposed on the optical axis of the scanning lens 27 and forms an image of the light spot of the primary imaging plane 28 on the imaging plane 7 through the shape converting section 32. A second mirror 30 is installed between the objective lens 33 and the imaging plane 7. When the second mirror 30 receives the reflected light beam R2 in the vertical direction (surface direction parallel to the imaging surface 7) from the first mirror 29 through the objective lens 33, the second mirror 30 has a central optical axis 36 as shown in FIG. 4B. It is installed with an angle of 45 degrees so that the traveling direction is a light beam R3 converted by 90 degrees in the horizontal direction (direction orthogonal to the imaging plane 7) . Further, the second mirror 30 installed at an angle of 45 degrees is such that the central optical axis 36 light beam reflected by the reflecting surface when viewed from the horizontal plane as shown in FIG. In the reflected light beam R1 from 3, the intersection 19 having an angle of 90 degrees with respect to the central optical axis light beam is formed. Thereby, the light beam R3 reflected by the second mirror 30 forms an image 15 on the same image plane 7 on which the image 11 by the first optical unit 4 forms an image.

  Since the second optical unit 5 is configured as described above, when the n2 surface of the polygon mirror 3 rotates in the direction of the arrow in FIG. 4A, the beam 13 from the second light source 2 becomes a reflected light beam R1, and the surface of the scanning lens 27 is moved. Scans and passes in the main scanning direction. FIG. 4A shows the time when the reflected light beam R1 is at the positions 34a, 34b, and 34c of the scanning lens 27, and images are formed as light spots on the positions 35a, 35b, and 35c of the primary imaging surface 28, respectively. This light spot is turned 90 degrees vertically by the first mirror 29 and passes through the shape converter 32 as a reflected light beam R2. After passing through the shape conversion unit 32, the light spot of the reflected light beam that has moved in the main scanning direction is converted into a Y-shaped line 15 oriented in the sub-scanning direction. When the Y-type line 15 is reflected by the second mirror 30 and becomes a light beam R3, the direction is changed by 90 degrees in the horizontal direction to form an X-type line. The light beam converted into the X-type line moves toward the image plane 7 by the rotation of the reflecting surface n2, and scans in the sub-scanning direction as images 15a, 15b, and 15c.

  The principle of laser scanning according to the present invention has been described above based on the drawings. As is apparent from this explanation, the present invention is significant in that X and Y lines 15 and 11 are generated simultaneously using one polygon mirror, and the same image plane 7 is scanned with both lines. It is a feature.

  FIG. 7 is an explanatory diagram showing the inside of the control unit 8 shown in FIG. 1 as a block diagram, and is a part for controlling the relation between the rotation of the polygon mirror and the light source. In the figure, reference numeral 40 denotes an origin position detection unit of the first light source. The beam 6 from the first light source 1 shown in FIG. 1 is reflected by the n1 surface of the polygon mirror 3 and a part of the light directed to the first optical unit 4 is obtained. In response, the origin position when scanning in the main scanning direction is detected. Reference numeral 41 denotes an origin position detection unit of the second light source. The beam 13 from the second light source 2 is reflected by the n2 surface of the polygon mirror 3 and receives a part of the light directed to the second optical unit 5 to scan in the sub-scanning direction. Detect the origin position when Reference numerals 42 and 43 denote control units on the X side and Y side in the control unit 8, which control the generation of the Y type line 11 and the X type line 15, respectively. Since the contents of the X-side control unit 42 and the Y-side control unit 43 are almost the same, the X-side control unit 42 will be described. The counter 44 receives and counts the signal from the clock generator 45 and transmits the count value to the coincidence circuits 46a and 46b. The two registers 47 store the set values from the keyboard 12. In this example, the position where the first Y-type line 11-1 in FIG. 2A is projected to the register 47a and the nth Yth line in the register 47b. The projected position of the mold line 11n is set. A lighting pulse width setting circuit 48 receives a command from the keyboard 12 and sets a pulse width corresponding to the lighting time of the light source 1. A lighting signal generator 49 of the light source 1 receives a signal from the pulse width setting circuit 48 and instructs the first light source 1 to turn on the exposure width W1 of the Y-type line 11 (FIG. 2A).

  The operation will be described. First, a signal 50 to carry out scanning in the main scanning direction is transmitted from the keyboard 12 to the gate unit 51. Next, the two registers 47a and 47b are set and stored on the image plane where the Y-type lines 11-1 and 11n are projected. When the polygon mirror 3 rotates and the X-side origin position detection unit 40 receives the beam from the light source 1 and detects the position as the origin, the reset signal 52 is sent to the counter 44 to reset the contents. Then, the counter 44 receives the clock signal from the clock generator 45 corresponding to the rotation of the polygon mirror 3, counts the value, and sends the signal to the coincidence circuits 46a and 46b. During this time, the polygon mirror 3 continues to rotate and changes the reflection surface angle with respect to the beam 6. When the coincidence circuit 46a coincides with the first Y-line 11-1 projection position stored in the register 47a, a coincidence signal is transmitted to the gate unit 51. Since the main scanning command 50 is transmitted from the keyboard 12 to the gate 51 in advance, a signal is sent to the pulse width setting circuit 48. The pulse width setting circuit 48 transmits a signal corresponding to the set width W1 corresponding to one Y-type line 11-1 to the lighting signal generator 49, and the light source 1 is turned on. The light source 1 projects the Y-type line 11-1 in FIG. When the polygon mirror 3 further rotates and scanning in the main scanning direction corresponding to the width W1 of the Y-type line 11-1 is completed, the lighting command to the light source 1 is lost and the light is turned off.

  When the polygon mirror 3 further rotates to detect that the second coincidence circuit 46b coincides with the second value 11n set in the register 47b, a coincidence signal is sent to the gate unit 51 and signaled to the pulse width setting circuit 48. To communicate. Then, the circuit 48 transmits a signal to the lighting signal generator 49 in the same manner as described above, and the light source 1 is turned on for the designated amount. When the lighting corresponding to the width W1 of the Y-type line 11n is finished, the light source 1 is turned off. Thus, the light source lighting operation set in the registers 47a and 47b is completed, but the polygon mirror 3 continues to rotate thereafter. When the origin detection unit 40 receives the second origin detection signal, it sends a reset signal 52 to the counter 44 to reset the contents, and thereafter repeats the same operation as described above. Thereby, two Y-type lines 11-1 and 11n are repeatedly projected on the image plane. If it is desired to increase the number of lines 11 to be projected in addition to the two lines 11-1 and 11n, the number of registers 47 and matching circuits 46 may be increased.

  Since the content of the Y-type control unit 43 is the same as that of the X-side control unit 42 as described above, the description thereof is omitted. However, in the figure, the same reference numerals as those of the respective parts of the X-side control unit 42 are attached for easy understanding.

  Next, a case where the first Y-type line 11-1 shown in FIG. 2A is projected and then continuously projected as lines 11-2, 11-3,... Will be described. Projecting the Y-type line 11 continuously means connecting the Y-type line 11-1 and projecting 11-2, 11-3,... In order as shown in FIG. The line width W1 is Wn. Therefore, if the width Wn is set in the pulse width setting circuit 48, the same processing can be performed.

  Next, FIG. 8 will be described. This is a modification of a part of FIG. 7 and shows only the X-side control unit 42. FIG. 7 illustrates the projection with the width W of the Y-type line 11 being constant as shown in FIGS. 2A and 2B. On the other hand, in FIG. 8, the line width W can be projected as W1, W2, W3... Wn as shown in FIG. In the figure, the same parts as those in FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted. However, a pulse width setting circuit is provided for each register 47a, 48b,. If W1, W2, W3... Wn are set from the keyboard 12 to each pulse width setting circuit 48, lines 11-1, 11-2, 11- having different width W values as shown in FIG. 3 can be obtained.

Since the control unit 8 has the above-described configuration, when performing only scanning in the main scanning direction on the imaging plane may do it conveys a signal 50 to the X-side control unit 42 in the gate unit 51 from the keyboard 12 When only scanning in the sub-scanning direction is performed, the signal 50 may be transmitted to the gate unit 51 in the Y-side control unit 43. When scanning in both the main and sub directions, the signal 50 is of course transmitted to both gate portions 51.

Next, Example 2 will be described with reference to FIGS. According to the second embodiment, a part of the first embodiment is modified, and the shape converting section 32 of the second optical unit 5 is placed outside the direction changing section 31 and installed outside the direction changing section 31, and an image is formed thereon. Position correction means 55 is added.
9, the reflected light beam R1 from the n1 surface of the polygon mirror 3 passes through the scanning lens 27 while moving in the main scanning direction as shown in FIGS. 4, 5, and 6, and the first mirror 29, the objective lens 33, The direction is changed through the second mirror 30, and the light beam moving in the main scanning direction is changed to the light beam moving in the sub-scanning direction. The redirected reflected light beam R3 passes through the shape conversion unit 32 installed in the vertical direction (sub-scanning direction) , is converted into an X-type line 15 and travels toward the image plane 7. That is, the light beam moving in the main scanning direction is changed in the sub-scanning direction by the direction changing unit 31 and then passed through the shape changing unit 32 to be directed to the image plane 7 as the X-type line 15. Therefore, compared to the case where the light beam that has passed through the shape conversion unit 32 of the first embodiment becomes a Y-type line, the light beam that has passed through the shape conversion unit 32 becomes an X-type line, and the direction of the line is different. It will be. However, this is a difference in whether the light beam traveling toward the shape converting unit 32 is in the main scanning direction or the sub-scanning direction, and there is no substantial difference.
In this example, since the image received by the second mirror 30 is only the light beam from the first mirror 29, the reflection surface width of the second mirror 30 can be made narrower than the width W4 shown in FIG. 4A. . This is because the image according to FIG. 4A is received by the second mirror 30 after being converted into a line by the shape converter 32.

FIG. 10 is an explanatory diagram when the imaging position correcting unit 55 is installed behind the shape converting unit 32 of the second optical unit 5. FIG. A shows a state in which the light beam from the shape converting unit 32 is projected as an X-type line 15 on the imaging plane 7. In the same figure, the image 15b by the light beam perpendicularly incident on the shape converting section 32 along the central optical axis 36 is arranged at an arbitrary pitch including the image formed on the near-field section 56. However, the images formed on the peripheral portion 57 by the off-axis light beam are arranged at a pitch that is coarser than that of the central portion 56.
This will be explained with reference to FIGS. C and D. When the beam 13 from the second light source 2 is reflected by the polygon mirror 3, the position of the reflection surface with respect to the beam 13 increases as the reflection surface angle increases. An error occurs. This is because there is a difference between the position of the focal length f of the objective lens 33 and the actual position on the image plane 7 installed on the plane as shown in FIG. Therefore, when the light beam 58 reflected by the mirror 3 in FIG. C becomes a dotted light beam 58a reflected by the mirror 3a after further rotation and forms an image on the image plane 7 in FIG. It is assumed that the position is a distance L3 away from the central optical axis 36. Assuming that the rotation angle of the mirror 3 when the light beam 58 in FIG. It will be a distant position. At this time, L3 <L4 as is apparent from the figure. Therefore, for example, when the polygon mirror is rotated by θ, if the X-type line 15 projected on the image plane 7 is projected at an interval of 5 mm in the vicinity of the central optical axis portion 56 as shown in FIG. Even at a rotation of θ, an interval of 5 mm or more is obtained. The total length L5 (FIG. 10A) of the image 15 is determined by the diameter φ of each light beam incident on the shape conversion unit 32, the diameter of the shape conversion unit 32, and the like. If it occurs, it is not preferable in terms of management.
In FIG. 10B, in order to eliminate this error and to project each line image 15 at equal intervals, an imaging position correcting means 55 is installed. This correction means is composed of a rectangular fθ lens, and this is installed at the rear position of the shape conversion unit 32, thereby correcting the image formation position on the image formation surface in proportion to the rotation angle θ of the mirror 3. . The correction means 55 is installed not only in the second optical unit 5 but also in the first optical unit 4 so that an image with stable quality in both the main and sub-scanning directions is obtained.

Next, Example 3 will be described with reference to FIG. In this embodiment, the polygon mirror 3 is partially changed. In the figure, the polygon mirror 3b has an even number (four in the figure) of reflecting surfaces 53, and the reflecting surfaces 53 are configured as non-reflecting surfaces 53b every other surface. The non-reflecting surface 53b is formed by applying a surface with, for example, a black paint, and when receiving a beam from a light source, the non-reflecting surface 53b absorbs the light and blocks the generation of a reflected light beam.
If such a polygon mirror 3b is used to cause the beam 6 from the first light source 1 to face the arbitrary reflection surface n1 in the reflection surface 53 and generate a Y-type line, the n2 surface following the n1 surface is non- It becomes the reflective surface 53b. Therefore, even if the beam 13 from the second light source 2 is directed toward the n2 plane simultaneously with the beam 6 of the first light source 1, the beam 13 is absorbed and not reflected because it is a non-reflecting surface 53b. Therefore, the beam 13 from the second light source 2 must wait until the n2 plane passes and the n1 plane faces the opposite position. Therefore, in the case of this example, while the Y-type line 11 is projected by the n1 surface and the first optical unit 4, the generation of the X-type line 15 of the second optical unit 5 is stopped, and the second optical unit 5 causes the X-type line 15 to be generated. While the line 15 is being generated, the generation of the Y-type line 11 is suspended. However, since the timing of the pause has regularity for each non-reflecting surface, the Y-type line 11 and the X-type line 15 are generated alternately.

Next, Example 4 will be described with reference to FIGS. In this embodiment, the shape converters 22 and 32 are changed from the straight shape described so far to a curved shape. In FIG. 12, the configuration of the scanning optical system P is almost the same as that of the first embodiment. However, the scanning lenses 20 and 27 and the objective lenses 23 and 33 are removed from the first and second optical units 4 and 5 to perform optical scanning. The entire system P is reduced in size. The light from the light source 1 is reflected by the polygon mirror 3 and travels toward the curved shape converting unit 22 c of the first optical unit 4, where it is converted to the Y-type line 11 and travels toward the image plane 7. The curved shape conversion unit 22c will be described in detail later with reference to FIG. 13. If the polygon mirror 3 rotates in the same direction as in the first embodiment, the reflected light beam is converted into a curved shape according to the rotation angle of the n1 surface. Scans and passes through the surface of the portion 22c in the main scanning direction. The figure shows a state in which the three Y-shaped lines 11a, 11b, and 11c generated by the passage are projected onto the image plane 7. In this example, since the objective lens 23 is removed from the first optical unit 4 as described above, the direction in which the Y-type line 11 moves on the image plane is opposite to the arrow 10 in FIG. become.
The light beam R1 reflected by the polygon mirror 3 in the second optical unit 5 is also redirected by 90 degrees in the vertical direction (surface direction parallel to the imaging surface 7) by the first mirror 29 of the second optical unit 5 to become the light beam R2. Head to the second mirror 30. Therefore, the light beam R3 that has been redirected in the horizontal direction (the direction orthogonal to the imaging plane 7) and moved in the sub-scanning direction passes through the curved shape converting section 32c having a vertical shape (sub-scanning direction). . By this passage, each light flux forms an X-type line 15a, 15b, 15c and forms an image on the image plane 7. Also in this case, since the objective lens 33 is removed from the second optical unit 5 in the same manner as the Y-type line 11 of the first optical unit 4, the X-type line 15 is formed on the imaging surface with the arrow 14 in FIG. Moves in the reverse direction 59.

FIG. 13 is a diagram for explaining the curved shape conversion units 22 c and 32 c installed in the first and second optical units 4 and 5. 10A shows a state in which the light beam that has passed through the straight shape converting section 32 is projected as X-type lines 15b and 15c on the image plane 7, as in FIG. 10A. Of the projected X-type line 15, a line indicated as 15 b coincides with the line 15 b projected on the imaging plane through the position 34 b of the scanning lens 27 and the position 35 b of the primary imaging plane 28 in FIG. 4A. . That is, it coincides with the image projected on the imaging plane by the light beam passing on the central optical axis connecting the scanning lens 27 and the objective lens 33. Although the light beam passing through the central optical axis is shown as 60 in FIG. 13, when the light passes through the straight shape converting unit 32 because it is the light beam 60 of the central optical axis, the light beam passes through the central axis 61 of the converting unit 32. Passes through with an angle of 0 degrees (normal incidence).
On the other hand, another X-type line 15c projected onto the imaging plane is a line 15a projected onto the imaging plane via the position 34a of the scanning lens 27 and the position 35a of the primary imaging plane 28 in FIG. 4A. Matches. That is, the line 15 c in FIG. 13A coincides with the image 15 a projected by the off-axis light beam deviating from the central optical axis connecting the scanning lens 27 and the objective lens 33. Although this off-axis light beam is shown as 62 in FIG. 13, it is an off-axis light beam and therefore has an angle of 0 ° or more with respect to the central axis 61 when passing through the vertical shape converting unit 32. And enter. As a result, the light beam 62 passes through the shape converting section 32 in an oblique manner, and forms an image 15c on the image plane 7. Therefore, the image 15 c is a curved image corresponding to the passing angle of the shape converting unit 32. In the drawing, this is shown as a curved line 15cc in which the end of the line 15c is shifted from the center by L6 in the Y direction. Further, in the case of the first optical unit 4, the line 15 cc is a Y-type line 11 cc, so that an error of L7 + L7 occurs in the X direction. The values of L6 and L7 vary depending on the position of the light beam passing through the straight shape conversion units 22 and 32.

In FIG. 13B, in order to prevent the above-described adverse effects, the straight shape conversion unit 32 is curved and installed as 32c. In the figure, the light beam 60 passing through the central optical axis passes through the central axis 61c of the curved shape converting part 32c with an angle of 0 degrees, and forms an image of a 15b X-type line on the imaging plane 7. The light beam 62 passing through one off-axis also passes through the curved shape conversion unit 32c, and forms an image of the 15c X-type line on the image plane 7. However, since the central axis 61c of the shape converting unit 32c is curved so as to be perpendicularly incident even with the off-axis light beam 62, the image 15c is an X-type line under the same conditions as the image 15b of the central optical axis light beam 60. 15c is imaged.
FIG. 13C supplements the above description, and the state in which all of the central optical axis light beam 60 and the two off-axis light beams 62 and 63 that pass through the curved shape converting unit 32c of the second optical unit pass at an angle of 0 degrees. Is shown. With such a curved shape conversion unit 32c, the problem of L6 and L7 shown in FIG. 13A is eliminated, and a line 15c having the same conditions as the line 15b of the central optical axis light beam 60 is created on the image plane 7. I can go. In FIG. B, the shape conversion unit 32c of the second optical unit is described as an example, but it is natural that the shape conversion unit 22c of the first optical unit shown in FIG. 12 has a similar curved shape. It will be apparent that the off-axis light beam 63 in FIG. C is a light beam for projecting the line 15a in FIG.

  As described above, in the present invention, the entire apparatus can be made portable by reducing the size and operating parts of the scanning optical system. Even if the distance between the scanning optical system P and the imaging plane 7 is changed from several meters to several tens of meters, the performance can be maintained.

1 is a schematic block diagram illustrating a laser scanning device according to the present invention. The figure explaining the Y type line on an image plane. Explanatory drawing of a 1st optical part. The top view and front view of a 2nd optical part. The right view and explanatory drawing of a 2nd optical part. The perspective schematic diagram for description of a 2nd optical part. Explanatory drawing which shows the inside of a control part as a block diagram. The block diagram for description which deform | transformed a part of FIG. FIG. 6 is a schematic perspective view of an optical system for explaining a second embodiment. Explanatory drawing of an imaging position correction means. FIG. 6 is an explanatory diagram of a polygon mirror according to a third embodiment. FIG. 6 is a schematic perspective view of an optical system for explaining a fourth embodiment. FIG. 13 is a partial detailed explanatory diagram of FIG. 12.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... 1st semiconductor laser light source 2 ... 2nd semiconductor laser light source 3 ... Polygon mirror 4 ... 1st optical part 5 ... 2nd optical part 6 ... Beam 7 ... Connection Image plane 8 ... Control unit 9 ... Polygon motor 11 ... Y-type line 12 ... Input unit 13 ... Beam 15 ... X-type line 20 ... Scanning lens 21 ... Primary Imaging plane 22 ... Shape conversion section 23 ... Objective lens 27 ... Scan lens 28 ... Primary imaging plane 29 ... First mirror 30 ... Second mirror 31 ... Direction change Part 32 ... Shape conversion part 33 ... Objective lens 36 ... Center optical axis 40 ... X side origin position detection part 41 ... Y side origin position detection part 42 ... X side Control unit 43... Y side control unit 44... Counter 45... Clock generation unit 46 .. matching circuit 47... Register 48 .. lighting pulse width setting circuit 49. Part 50: Signal 51 ... Gate part 52 ... Reset signal 53 ... Reflecting surface 55 ... Imaging position correction means 56 ... Center part 57 ... Peripheral part 58 ... Light flux 60 ... Center optical axis light beam 61 ... Center axis 62 ... Off-axis light beam P ... Scanning optical system

Claims (6)

The light beam from the first semiconductor laser light source is applied to a polygon mirror having n reflection surfaces, and the reflected light is directed to the image formation surface via the shape conversion unit, and on the image formation surface according to the rotation of the polygon mirror. A first optical unit that scans in the main scanning direction ;
The light beam from the second semiconductor laser light source is applied to the polygon mirror, the reflected light is directed to the image formation surface via the shape conversion unit and the direction conversion unit, and the image formation surface is sub-scanned according to the rotation of the polygon mirror. A second optical unit that scans in a direction ;
Respectively installed in the first and second optical units, receiving reflected light moving in the main scanning direction from the polygon mirror , and converting the reflected light into a line-shaped reflected light with the light spot of the reflected light oriented in the sub-scanning direction. A shape converter,
A direction changing unit that is installed in the second optical unit, receives line-shaped reflected light in the sub-scanning direction from the shape converting unit, and changes the direction of the reflected light to line-shaped reflected light in the main scanning direction. And
The imaging surface 7 is scanned in the main scanning direction with the line-shaped reflected light oriented in the sub-scanning direction by the first optical unit, and is connected by the line-shaped reflected light oriented in the main scanning direction by the second optical unit. A laser scanning device characterized in that an image surface is scanned in the sub-scanning direction, and two line-shaped reflected lights are scanned in the main and sub-directions on the same imaging surface . A scanning lens that applies light beams from the first and second semiconductor laser light sources to one polygon mirror and directs the reflected light to each primary imaging plane as moving light in the main scanning direction;
An objective lens installed on the same optical axis as both scanning lenses, and directing reflected light of both primary imaging surfaces to the same imaging surface;
A rod installed between the scanning lens and the objective lens, which receives the reflected light moving in the main scanning direction from the primary imaging plane and converts it into a line-shaped reflected light with the reflected light point oriented in the sub-scanning direction 2. The laser scanning device according to claim 1, wherein the first and second optical units are provided with a shape conversion unit using a lens . A first mirror disposed between the primary image forming surface of the second optical unit and the shape converting unit, and a second mirror disposed between the objective lens and the image forming surface;
The first mirror receives reflected light moving in the main scanning direction through the primary imaging plane and changes the direction so that the traveling direction of the central optical axis light beam is parallel to the imaging plane, and the second mirror is the first mirror. Receiving the reflected light from the mirror, the direction of travel of the central optical axis light beam is changed so that it is perpendicular to the imaging plane,
The reflected light traveling in the main scanning direction reflected by the first mirror is redirected to the reflected light that is reflected by the second mirror and moved in the sub-scanning direction, and the converted reflected light is directed toward the imaging surface. The laser scanning device according to claim 1, wherein the direction changing portion is used. Imaging position correction composed of an fθ lens that receives reflected light from the polygon mirror through the shape conversion section in the first and second optical sections and directs the reflected light to an imaging plane position proportional to the rotation angle θ of the polygon mirror. 3. The laser scanning apparatus according to claim 1, wherein the means is installed in the first and second optical units. The light beam from the first semiconductor laser light source is applied to a polygon mirror having n reflection surfaces, and the reflected light is directed to the image formation surface via the shape conversion unit, and on the image formation surface according to the rotation of the polygon mirror. A first optical unit that scans in the main scanning direction;
The light beam from the second semiconductor laser light source is applied to the polygon mirror, and the reflected light is directed from the direction changing unit to the image forming surface via the shape converting unit, and the image forming surface is sub-scanned according to the rotation of the polygon mirror. A second optical unit that scans in a direction;
A shape conversion unit that is installed in the first optical unit and receives reflected light moving in the main scanning direction from the polygon mirror, and converts the reflected light into a reflected light having a shape with the light spot of the reflected light oriented in the sub-scanning direction. When,
The second mirror is installed in the second optical section and receives reflected light moving in the main scanning direction from the polygon mirror by the first mirror, and the traveling direction of its central optical axis is parallel to the imaging surface. The reflected light is received by the second mirror, the direction of travel of the central optical axis light beam is changed so as to be orthogonal to the imaging plane, and the reflected light that moves in the sub-scanning direction is changed to the imaging plane. And
A shape converting unit that converts the light spot of the reflected light received from the direction changing unit into a line-shaped reflected light having a direction in the main scanning direction;
The imaging surface is scanned in the main scanning direction with the reflected light of the line shape oriented in the sub-scanning direction by the first optical unit, and the image is formed with the reflected light of the line shape oriented in the main scanning direction by the second optical unit A laser scanning device characterized in that the surface is scanned in the sub-scanning direction, and two line-shaped reflected lights are scanned in the main and sub-directions on the same imaging surface . A rod lens that receives the reflected light from the polygon mirror and converts the reflected light point to a line-shaped reflected light is formed into a curved shape, and when the reflected light passes through the curved rod lens, the passing light is converted into a rod. lens laser scanning apparatus according to claim 1, 5, wherein it has a shape conversion unit configured to be the angle of incidence perpendicular to the central axis of.