JP2017107082A - Optical scanning device, optical scanning method and surface inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanning device which can correctly scan a wide range at high speed.SOLUTION: An optical scanning device 100 comprises: a semiconductor laser 10 for radiating a laser beam; a line generator lens 20 for extending the laser beam which is radiated from the semiconductor laser 10 to only an uniaxial direction; a reflection mirror 30 for reflecting the laser beam which is radiated from the line generator lens 20 and making the laser beam enter an inner peripheral face of a rotary shield plate 40; a pin hole 44 provided on the rotary shield plate 40, and crosses an optical path of the laser beam following to rotation of the rotary shield plate 40; a cylindrical lens 50 provided on an outer peripheral face of the rotary shield plate 40, and collimates the laser beam which passed the pin hole 44; and a telecentric lens 60 which converges the laser beam radiated from the cylindrical lens 50. The rotary shield plate 40 is formed into a cylindrical shape of surrounding the reflection mirror 30, and rotates around an optical axis Z as a rotation axis.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical scanning apparatus and optical scanning method for scanning an object with a laser beam (laser beam), and a surface inspection apparatus including the optical scanning apparatus.

  There are known an inspection apparatus that inspects an object based on light that is irradiated on the object, reflected by the object, or transmitted through the object, and an analysis apparatus that analyzes the object. For example, a surface inspection apparatus that detects the presence or absence of foreign matter or the presence of defects on the surface of an object based on laser light that is irradiated on the object and reflected by the object or transmitted through the object is known. It has been.

  The inspection apparatus and the analysis apparatus as described above include an optical scanning device that scans an object with a laser beam (laser beam), and the optical scanning device linearly changes the irradiation position of the laser beam on the surface of the object. The object is scanned back and forth by laser light.

  Conventionally, a polygon mirror that is driven to rotate, a galvano mirror that is driven to reciprocate, and the like have been used to move the irradiation position of the laser beam on the surface of the object. Further, MEMS (Micro Electro Mechanical Systems) may be used for moving the irradiation position of the laser beam on the surface of the object.

  When moving the irradiation position of the laser beam on the surface of the object using the polygon mirror, that is, when scanning the surface of the object with the laser beam, the polygon mirror is moved while the laser beam emitted from the light source is incident on the polygon mirror. Rotate. Then, the incident angle of the laser beam on each reflecting surface of the polygon mirror changes continuously. Thereby, the incident position on the surface of the object of the laser light reflected toward the object by each reflecting surface of the polygon mirror, that is, the irradiation position of the laser light on the object surface is moved.

  When moving the irradiation position of the laser beam on the surface of the object using the galvanometer mirror, that is, when scanning the surface of the object with the laser beam, the galvanometer mirror is placed while the laser beam emitted from the light source is incident on the galvanometer mirror. Rock. Then, the incident angle of the laser beam on the reflecting surface of the galvanometer mirror continuously changes. Thereby, the incident position on the object surface of the laser beam reflected toward the object by the reflecting surface, that is, the irradiation position of the laser beam on the object surface moves.

  When the irradiation position of the laser beam on the surface of the object is moved using MEMS, the principle is basically the same as the case of using the galvanometer mirror. That is, the micromirror included in the MEMS is supported by the hinge so as to be tiltable. The micromirror is oscillated by continuously inclining the micromirror in the plus direction and the minus direction by an electric signal. Then, the incident position on the object surface of the laser beam reflected toward the object by the micromirror, that is, the irradiation position of the laser beam on the object surface moves.

JP 2009-25711 A

  Since the polygon mirror is rotationally driven in one direction around a drive shaft provided at the center thereof, the influence of inertia is small. Therefore, the polygon mirror can be easily rotated at a high speed. That is, if a polygon mirror is used, the scanning speed can be easily increased.

  However, the drive axis (rotation axis) of the polygon mirror is at the center of the polygon mirror, while each reflecting surface is a flat surface and at the outer periphery of the polygon mirror. For this reason, when a laser beam is incident on each reflecting surface of the rotating polygon mirror, the incident position of the laser beam on the reflecting surface is not a specific point. In other words, the incident position of the laser beam on the reflecting surface changes continuously. As a result, when the surface of the object is irradiated with the laser beam using the polygon mirror, the irradiation position cannot be accurately controlled. Such displacement of the irradiation position is sometimes called “image collapse”.

  On the other hand, the incident position of the laser beam on the reflecting surface of the galvanometer mirror is always a specific point, and the phenomenon such as “image collapse” does not occur. However, the galvanometer mirror driven reciprocally is greatly affected by inertia. For this reason, it is not easy to swing the galvanometer mirror at high speed. That is, when a galvano mirror is used, it is difficult to increase the scanning speed.

  MEMS micromirrors have excellent responsiveness and are suitable for increasing the scanning speed. However, since the tilt angle of the micromirror is small, the range that can be scanned by one line becomes narrow when MEMS is used. Further, in order to widen the range that can be scanned by one line, it is necessary to increase the distance between the MEMS and the object, resulting in an increase in the size of the apparatus.

  An object of the present invention is to realize an optical scanning device and an optical scanning method capable of scanning a wide range at high speed and accurately.

  The optical scanning device of the present invention is an optical scanning device that scans an object with a laser beam, the light source emitting a laser beam, and the laser beam emitted from the light source extending in the X-axis direction orthogonal to the optical axis. On the other hand, the first optical element that is not expanded in the Y-axis direction orthogonal to the optical axis and the X-axis direction, and the traveling direction of the laser light emitted from the first optical element are converted to change the rotation shielding plate. A second optical element that is incident on a peripheral surface; provided on the rotation shielding plate; provided on an outer peripheral surface of the rotation shielding plate; an opening that crosses an optical path of a laser beam as the rotation shielding plate rotates; A third optical element that collimates the laser light that has passed through the opening in the X-axis direction, and a fourth optical that condenses the laser light emitted from the third optical element in the X-axis direction and the Y-axis direction. An element. The rotation shielding plate has a cylindrical shape surrounding the second optical element, and rotates around an axis parallel to the optical axis.

  The optical scanning method of the present invention is an optical scanning method for scanning an object with laser light, the first step of emitting laser light from a light source, and the laser light emitted from the light source orthogonal to the optical axis X A second step that extends in the axial direction but does not extend in the Y-axis direction orthogonal to the optical axis and the X-axis direction; and a cylindrical shielding plate that is driven to rotate by changing the traveling direction of the laser light. A third step of causing laser light to enter the inner peripheral surface; and a fourth step of emitting laser light incident on the inner peripheral surface of the shielding plate to the outside of the shielding plate through an opening provided in the inner peripheral surface. A step, a fifth step of collimating the laser light that has passed through the opening in the X-axis direction, and condensing the laser light collimated by the fifth step in the X-axis direction and the Y-axis direction. And a sixth step, Plate is rotationally driven an axis parallel with the optical axis as a rotation axis.

  The surface inspection apparatus of the present invention includes an optical scanning device that scans an object with laser light, and the presence or absence of foreign matter on the surface of the object based on laser light reflected by the object or transmitted through the object. And a detecting device for detecting. The optical scanning device includes a light source that emits laser light and a laser light emitted from the light source that extends in the X-axis direction orthogonal to the optical axis, while the optical axis and the Y-axis orthogonal to the X-axis direction. A first optical element that is not expanded in the axial direction; a second optical element that changes the traveling direction of the laser light emitted from the first optical element and enters the inner peripheral surface of the rotation shielding plate; and the rotation shielding plate An opening that crosses the optical path of the laser beam as the rotary shielding plate rotates, and a laser beam that is provided on the outer peripheral surface of the rotary shielding plate and passes through the opening is made parallel in the X-axis direction. And a fourth optical element that condenses the laser light emitted from the third optical element in the X-axis direction and the Y-axis direction, and the rotation shielding plate includes the first optical element. Has a cylindrical shape that surrounds two optical elements Rotates an axis parallel with the optical axis as a rotation axis.

  In one aspect of the present invention, a plurality of the openings and a plurality of the third optical elements corresponding to the openings are provided.

  In another aspect of the invention, the plurality of openings and the third optical element are arranged at equal intervals in the rotation direction of the rotation shielding plate.

  In another aspect of the present invention, the opening is a pinhole or a slit that penetrates the rotation shielding plate.

  In another aspect of the invention, the first optical element, the third optical element, and the fourth optical element are refractive optical elements, and the second optical element is a reflective optical element.

  In another aspect of the invention, the first optical element is a line generator lens, the second optical element is a reflecting mirror, the third optical element is a cylindrical lens, and the fourth optical element is a telecentric lens. It is.

  According to the present invention, an optical scanning device and an optical scanning method capable of scanning a wide range at high speed and accurately are realized.

It is a block diagram which shows an example of embodiment of an optical scanning device. It is a schematic diagram which shows the optical effect | action of a line generator lens. It is a schematic diagram which shows the optical effect | action of a reflective lens. It is sectional drawing of a rotation shielding board. It is a schematic diagram which shows the optical effect | action of a telecentric lens. It is a schematic diagram which shows the movement state of the laser beam accompanying rotation of a rotation shielding board. It is a block diagram which shows an example of embodiment of a surface inspection apparatus.

  Hereinafter, an example of an embodiment of the surface inspection apparatus of the present invention will be described. The surface inspection apparatus according to the present embodiment includes an optical scanning device that scans a workpiece as an object with laser light, and a detection device that detects the presence or absence of foreign matter on the workpiece surface based on the laser light transmitted through the workpiece. ing.

  The optical scanning device constituting the surface inspection apparatus according to the present embodiment irradiates a workpiece with laser light and linearly moves the irradiation position of the laser beam on the workpiece. That is, the workpiece is line-scanned by laser light. In addition, the detection device constituting the surface inspection apparatus according to the present embodiment detects the presence or absence of foreign matter on the surface of the workpiece based on the laser beam irradiated to the workpiece by the optical scanning device and transmitted through the workpiece. As described above, the surface inspection apparatus according to the present embodiment uses a workpiece that can transmit laser light as an inspection target.

  FIG. 1 is a schematic diagram showing the overall configuration of the optical scanning device 100. As illustrated, the optical scanning device 100 includes a light source 10, a first optical element 20, a second optical element 30, a rotation shielding plate 40, a third optical element 50, and a fourth optical element 60.

  The illustrated light source 10 is a laser light source that emits laser light having a predetermined wavelength, and more specifically a semiconductor laser. Therefore, in the following description, the light source 10 is referred to as “semiconductor laser 10”.

  The illustrated first optical element 20, third optical element 50, and fourth optical element 60 are refractive optical elements. More specifically, the first optical element 20 is a line generator lens, the third optical element 50 is a cylindrical lens, and the fourth optical element 60 is a telecentric lens. The illustrated second optical element 30 is a reflective optical element, more specifically a reflective mirror. Therefore, in the following description, the first optical element 20, the third optical element 50, and the fourth optical element 60 are referred to as “line generator lens 20”, “cylindrical lens 50”, and “telecentric lens 60”, respectively. The second optical element 30 is referred to as a “reflecting mirror 30”.

  That is, the optical scanning device 100 according to this embodiment includes at least the semiconductor laser 10, the line generator lens 20, the reflection mirror 30, the rotation shielding plate 40, the cylindrical lens 50, and the telecentric lens 60.

  The semiconductor laser 10 emits laser light having a wavelength of 632.8 [nm]. In other words, the first step of emitting laser light from the light source is performed by the semiconductor laser 10. However, the oscillation wavelength of the semiconductor laser 10 is not limited to 632.8 [nm], and can be set arbitrarily. Between the semiconductor laser 10 and the line generator lens 20, it is preferable to arrange an optical module for making the laser light emitted from the semiconductor laser 10 efficiently enter the line generator lens 20. In this embodiment, a beam extractor is arranged. A panda 11 is arranged. That is, the beam expander 11 is arranged on the optical path of the laser light emitted from the semiconductor laser 10, and the laser light emitted from the semiconductor laser 10 enters the line generator lens 20 through the beam expander 11.

  The line generator lens 20 extends the incident laser light only in a predetermined uniaxial direction to make the intensity distribution of the laser light uniform. As shown in FIG. 2, the line generator lens 20 in the present embodiment extends the laser light in the X-axis direction orthogonal to the optical axis Z of the laser light, while the optical axis Z and Y orthogonal to the X-axis direction. Do not stretch in the axial direction. In the following description, the direction of the optical axis Z of the laser light may be referred to as “Z-axis direction”.

  Laser light emitted from the semiconductor laser 10 is fan-shaped light spreading in the X-axis direction and converted into light having a substantially uniform intensity distribution by the optical action of the line generator lens 20. In other words, the second step of extending the laser light emitted from the light source by the line generator lens 20 in the X-axis direction orthogonal to the optical axis, but not extending in the Y-axis direction orthogonal to the optical axis and the X-axis direction. Is executed.

  As shown in FIG. 1, the laser light emitted from the line generator lens 20 is incident on the reflection mirror 30. The reflection mirror 30 is a total reflection mirror and reflects incident laser light in a predetermined direction. As shown in FIG. 3, the reflection mirror 30 in the present embodiment is inclined at 45 degrees with respect to the optical axis Z of the laser light. Therefore, the traveling direction of the laser light incident on the reflection mirror 30 is converted by 90 degrees.

  Refer to FIG. 1 again. The rotation shielding plate 40 includes a circular bottom plate 41 and a cylindrical side plate 42 and has a cylindrical shape as a whole. The reflection mirror 30 is disposed inside the rotation shielding plate 40 and is surrounded by the side plate 42 of the rotation shielding plate 40. Therefore, the laser light whose traveling direction is converted by 90 degrees by the reflecting mirror 30 is incident on the inner surface of the side plate 42 of the rotation shielding plate 40, that is, the inner peripheral surface 42a. As described above, the reflection mirror 30 functions as an optical path conversion mirror that converts the optical path of the laser light emitted from the line generator lens 20 and causes the laser light to enter the inner peripheral surface 42 a of the rotation shielding plate 40. In other words, the reflection mirror 30 functions as a folding mirror that folds the laser light emitted from the line generator lens 20 and makes it incident on the inner peripheral surface 42 a of the rotation shielding plate 40.

  An electric motor 43 as a drive source is provided behind the bottom plate 41 of the rotation shielding plate 40. The electric motor 43 includes an output shaft (not shown) concentric with the optical axis Z of the laser light incident on the reflection mirror 30, and the tip of the output shaft is connected to the center of the bottom plate 41 of the rotation shielding plate 40. Yes. Therefore, when the electric motor 43 is operated, the rotation shielding plate 40 rotates with an axis parallel to the optical axis Z incident on the reflection mirror 30 (in the present embodiment, an axis that coincides with the optical axis Z) as a rotation axis. That is, the third step of changing the traveling direction of the laser light by the reflecting mirror 30 and causing the laser light to enter the inner peripheral surface of the cylindrical shielding plate that is rotationally driven is executed.

  As shown in FIG. 4, the side plate 42 of the rotation shielding plate 40 is provided with a plurality of pin holes 44 as openings. In the present embodiment, four pin holes 44 penetrating the side plate 42 are provided at equal intervals (90-degree intervals) in the rotation direction of the rotation shielding plate 40. These pinholes 44 cross the optical path of the laser light reflected by the reflection mirror 30 one after another as the rotation shielding plate 40 rotates. While the pinhole 44 crosses the optical path, the laser light passes through the pinhole 44 and is emitted out of the rotation shielding plate 40. In other words, the fourth step is performed in which the laser light incident on the inner peripheral surface of the shielding plate is emitted out of the shielding plate through the opening provided in the inner peripheral surface.

  Here, the laser light is expanded in the X-axis direction by the optical action of the line generator lens 20 (FIG. 1) and spreads in a fan shape. Therefore, the laser beam passes through the pinhole 44 and is emitted out of the rotation shielding plate 40 from the one end P1 to the other end P2 of the laser beam in which the pinhole 44 spreads in a fan shape. Thus, since the laser light passes through the rotating pinhole 44 and is emitted out of the rotation shielding plate 40, the laser light emitted outside the rotation shielding plate 40 moves together with the pinhole 44. Looks like you are doing.

  Further, the rotation shielding plate 40 is provided with a plurality of cylindrical lenses 50 corresponding to the respective pinholes 44. Specifically, four cylindrical lenses 50 are provided at an interval of 90 degrees on the outer peripheral surface 42 b of the rotation shielding plate 40, and the laser light that has passed through each pinhole 44 corresponds to the cylindrical hole corresponding to the pinhole 44. The light enters the lens 50.

  As shown in FIG. 1, the optical path of the laser light incident on the reflection mirror 30 is converted by 90 degrees by the reflection mirror 30. In FIG. 4, the reflection mirror 30 and the rotation shielding plate 40 are viewed from the side opposite to the incident direction of the laser light with respect to the reflection mirror 30. Therefore, in FIG. 4, the vertical direction of the paper is the Z-axis direction, the horizontal direction of the paper is the X-axis direction, and the direction perpendicular to the paper is the Y-axis direction.

  Laser light that has passed through the pinhole 44 and entered the cylindrical lens 50 is collimated by the optical action of the cylindrical lens 50. In other words, the fifth step of collimating the laser light that has passed through the opening of the shielding plate in the X-axis direction by the cylindrical lens 50 is executed.

  In the present embodiment, the distance between the cylindrical lens 50 and the center O of the laser light incident on the cylindrical lens 50 (fan-shaped light spreading in the X-axis direction) matches the focal length of the cylindrical lens 50. I'm allowed. In other words, the distance between the cylindrical lens 50 and the reflection mirror 30 and the focal length of the cylindrical lens 50 are matched. Therefore, the laser light emitted from the cylindrical lens 50 becomes parallel light having a circular cross section. That is, a laser beam having a circular beam shape is emitted from the cylindrical lens 50.

  Referring to FIG. 1 again, the laser light emitted from the cylindrical lens 50 is incident on the telecentric lens 60. The telecentric lens 60 is a one-sided telecentric lens and has a focal point. Therefore, as shown in FIG. 5, the laser light having a circular cross section emitted from the cylindrical lens 50 is condensed at the focal position of the telecentric lens 60 by the optical action of the telecentric lens 60. In other words, the sixth step of condensing the laser light collimated by the fifth step in the X-axis direction and the Y-axis direction by the telecentric lens 60 is executed.

  In the present embodiment, the workpiece W is transported below the telecentric lens 60 by a transport mechanism (not shown). Specifically, the workpiece W is conveyed to a position where the surface position thereof coincides with the focal position of the telecentric lens 60. Therefore, the laser beam is focused on the workpiece surface Ws.

  Here, the pinhole 44 and the cylindrical lens 50 move as the rotation shielding plate 40 rotates. Therefore, as shown in FIG. 6, the position of the laser beam condensed on the workpiece surface Ws by the telecentric lens 60, that is, the incident position of the laser beam on the workpiece surface Ws is the rotation of the rotation shielding plate 40 (= pinhole 44). And the movement of the cylindrical lens 50). In other words, the workpiece surface Ws is scanned by the laser light.

  As described at the beginning, the surface inspection apparatus according to the present embodiment detects the presence or absence of foreign matter on the workpiece surface Ws based on the laser beam transmitted through the workpiece W, in addition to the optical scanning device 100 described so far. Equipment. In FIG. 7, the outline of a structure of the surface inspection apparatus 1 which concerns on this embodiment is shown. The optical scanning device 100 and the detection device 200 constituting the surface inspection apparatus 1 are disposed so as to face each other with the workpiece W interposed therebetween. In other words, the workpiece W is transported between the optical scanning device 100 and the detection device 200 by a transport device (not shown). In other words, when the workpiece W is transported between the optical scanning device 100 and the detection device 200, the optical scanning device 100 is positioned above the workpiece W, and the detection device 200 is positioned below the workpiece W. At this time, as described above, the position of the workpiece surface Ws matches the focal position of the telecentric lens 60 of the optical scanning device 100. Then, the laser light applied to the workpiece W by the optical scanning device 100 passes through the workpiece W and enters the detection device 200.

  The detection device 200 includes a pair of first lens 201 and second lens 202, a spatial filter 203 provided between the first lens 201 and the second lens 202, a condenser 204, and a photodetector 205. Have. The laser light that has passed through the workpiece W first enters the first lens 201. The first lens 201 collimates the incident laser light and guides it to the second lens 202.

  However, a spatial filter 203 is disposed between the first lens 201 and the second lens 202. The spatial filter 203 shields the chief ray (main beam) of the laser beam that has passed through the workpiece W. Therefore, when no foreign matter is present on the workpiece surface Ws, the laser light transmitted through the workpiece W is blocked by the spatial filter 203 and does not reach the second lens 202. On the other hand, when foreign matter exists on the workpiece surface Ws and this foreign matter is irradiated with laser light, scattered light is generated. The scattered light reaches the second lens 202 without being blocked by the spatial filter 203. The scattered light incident on the second lens 202 is guided to the photodetector 205 via the second lens 202 and the condenser 204. The photodetector 205 outputs an electric signal (detection signal) corresponding to the intensity of the incident scattered light to a display device (not shown).

  Here, the intensity of the scattered light varies depending on the size of the foreign matter existing on the workpiece surface Ws. Specifically, the greater the foreign matter, the greater the intensity of the scattered light, and the level of the detection signal output from the photodetector 205 increases. The display device visualizes and displays the level of the detection signal output from the photodetector 205. For example, the display device generates a graph indicating the level of the detection signal and displays it on the liquid crystal monitor. Therefore, when a detection signal having a level higher than a predetermined level is shown in the graph displayed on the liquid crystal monitor, foreign matter larger than the predetermined size exists on the workpiece surface Ws. In this way, the presence or absence of foreign matter on the workpiece surface Ws is inspected.

  Of course, the entire surface of the workpiece surface Ws or a predetermined region is inspected by relatively moving the surface inspection apparatus 1 and the workpiece W. Further, the relative movement direction of the surface inspection apparatus 1 and the workpiece W is a direction that intersects the scanning direction of the optical scanning apparatus 100. For example, the optical scanning device 100 shown in FIG. 7 scans the workpiece W in the left-right direction on the paper surface. In this case, the workpiece surface Ws is inspected while moving at least one of the surface inspection apparatus 1 including the optical scanning device 100 and the workpiece W in a direction perpendicular to the paper surface.

  Referring to FIG. 4 again, the rotation shielding plate 40 is provided with four pin holes 44 at intervals of 90 degrees. Therefore, the number of scans per rotation of the rotation shielding plate is four. However, the number of pinholes 44 provided in the rotation shielding plate 40 is not limited to four, and may be three or less, or five or more. That is, if the number of pinholes 44 provided in the rotation shielding plate 40 is increased or decreased, the number of scans per rotation of the rotation shielding plate can be changed. Further, the scanning speed can be changed by increasing or decreasing the rotational speed of the rotary shielding plate 40.

  Since the rotation shielding plate 40 has a cylindrical shape, the rotation shielding plate 40 is not easily affected by inertia and is easily rotated at a high speed. However, from the viewpoint of rotating the rotation shielding plate 40 more smoothly and at a high speed, the plurality of pinholes 44 and the cylindrical lens 50 are It is preferable to arrange them at equal intervals. For example, when two sets of pinholes 44 and cylindrical lenses 50 are provided, it is preferable to arrange each set of pinholes 44 and cylindrical lenses 50 at intervals of 180 degrees. When three sets of pinholes 44 and cylindrical lenses 50 are provided, each set of pinholes 44 and cylindrical lenses 50 are arranged at intervals of 120 degrees, and when eight sets of pinholes 44 and cylindrical lenses 50 are provided. In this case, it is preferable that the pinholes 44 and the cylindrical lenses 50 of each group are arranged at intervals of 45 degrees. However, the irradiation range of the laser beam on the inner peripheral surface 42a of the rotation shielding plate 40 and the interval between the adjacent pinholes 44 are set so that two or more pinholes 44 do not cross the optical path of the laser beam at the same time. There is a need. That is, it is necessary to avoid that two pinholes 44 enter between P1 and P2 shown in FIG. In other words, if the interval between P1 and P2 shown in FIG. 4 is enlarged, the scanning range in one line can be enlarged.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the light source 10 shown in FIG. 1 is not limited to a semiconductor laser, and can be replaced with a gas laser, a solid-state laser, or another laser. Further, the wavelength of the laser light emitted from the light source 10 is not limited to the above wavelength. The beam expander 11 shown in FIG. 1 can be replaced with another optical module having the same optical action, for example, a beam focus lens.

  The line generator lens 20, the reflection mirror 30, the cylindrical lens 50, and the telecentric lens 60 in the above embodiment are examples of the first optical element, the second optical element, the third optical element, and the fourth optical element, respectively. It can be replaced with another optical element having an action.

  The optical scanning device according to the embodiment includes a first step of emitting laser light from a light source, and extending the laser light emitted from the light source in an X-axis direction perpendicular to the optical axis, while the optical axis and the X A second step that does not extend in the Y-axis direction orthogonal to the axial direction, and a third step that changes the traveling direction of the laser beam and causes the laser beam to be incident on the inner peripheral surface of the rotationally driven cylindrical shielding plate; A fourth step of emitting laser light incident on the inner peripheral surface of the shielding plate to the outside of the shielding plate through an opening provided in the inner peripheral surface; and the laser light that has passed through the opening is An optical scanning method including a fifth step of collimating in the X-axis direction and a sixth step of condensing the laser light collimated in the fifth step in the X-axis direction and the Y-axis direction is executed. . Specifically, the first step is executed by the semiconductor laser 10, the second step is executed by the line generator lens 20, the third step is executed by the reflecting mirror 30, and the fifth step is executed by the cylindrical lens 50. And the sixth step is executed by the telecentric lens 60. Moreover, the said 4th process is performed by performing the said 3rd process, rotating the rotation shielding board 40. FIG. However, the line generator lens 20, the reflection mirror 30, the cylindrical lens 50, and the telecentric lens 60 are examples of means for performing the second step, the third step, the fifth step, and the sixth step.

  In the above embodiment, the distance between the cylindrical lens 50 shown in FIG. 4 and the center O of the fan-shaped light incident on the cylindrical lens 50 and the focal length of the cylindrical lens 50 are made to coincide with each other in a circular cross section. Got the light. However, the cylindrical lens 50 shown in the figure can be replaced with another cylindrical lens having a different focal length to obtain parallel light having a cross-sectional shape other than circular (for example, elliptical). Further, the cylindrical lens 50 may be omitted, and the light that has passed through the pinhole 44 may be directly incident on the telecentric lens 60 (FIG. 5). The pinhole 44 can be replaced with a slit or other opening.

  The surface inspection apparatus 1 according to the above embodiment inspects the surface of an object based on light transmitted through the object. However, a surface inspection apparatus that inspects the surface of an object based on light reflected by the object is also included in the surface inspection apparatus of the present invention.

  The optical scanning device of the present invention can be used in various inspection apparatuses other than the surface inspection apparatus. Furthermore, the optical scanning apparatus of the present invention can be used in apparatuses other than the inspection apparatus, for example, can be used in an analysis apparatus for analyzing a component of an object, and can be used for photo-modification and optical cleaning. It can also be used for applications. In addition, if a detector such as a PSD (Position Sensing Detector) capable of detecting a change in the position of the beam is provided on the light receiving side, it can also be used for inspection of the surface shape and flatness of the object.

1 Surface inspection device 10 Light source (semiconductor laser)
11 Beam expander 20 First optical element (line generator lens)
30 Second optical element (reflection mirror)
40 rotation shielding plate 41 bottom plate 42 side plate 42a inner peripheral surface 42b outer peripheral surface 43 electric motor 44 pinhole 50 third optical element (cylindrical lens)
60 Fourth optical element (telecentric lens)
DESCRIPTION OF SYMBOLS 100 Optical scanning device 200 Detection apparatus 201 1st lens 202 2nd lens 203 Spatial filter 204 Condenser 205 Photodetector W Work Ws Work surface Z Optical axis

Claims (8)

An optical scanning device that scans an object with laser light,
A light source that emits laser light;
A first optical element that expands the laser light emitted from the light source in the X-axis direction orthogonal to the optical axis, but does not extend in the Y-axis direction orthogonal to the optical axis and the X-axis direction;
A second optical element that converts the traveling direction of the laser light emitted from the first optical element and enters the inner peripheral surface of the rotation shielding plate;
An opening that is provided in the rotation shielding plate and that crosses the optical path of the laser light as the rotation shielding plate rotates;
A third optical element that is provided on the outer peripheral surface of the rotary shielding plate and parallelizes the laser light that has passed through the opening in the X-axis direction;
A fourth optical element for condensing the laser light emitted from the third optical element in the X-axis direction and the Y-axis direction,
The rotation shielding plate has a cylindrical shape surrounding the second optical element, and rotates around an axis parallel to the optical axis.
Optical scanning device. The optical scanning device according to claim 1,
A plurality of the openings, and a plurality of the third optical elements corresponding to the openings, respectively.
Optical scanning device. The optical scanning device according to claim 2,
The plurality of openings and the third optical element are arranged at equal intervals in the rotation direction of the rotation shielding plate,
Optical scanning device. In the optical scanning device according to any one of claims 1 to 3,
The opening is a pinhole or slit that penetrates the rotation shielding plate.
Optical scanning device. In the optical scanning device according to any one of claims 1 to 4,
The first optical element, the third optical element and the fourth optical element are refractive optical elements,
The second optical element is a reflective optical element;
Optical scanning device. The optical scanning device according to claim 5,
The first optical element is a line generator lens;
The second optical element is a reflection mirror;
The third optical element is a cylindrical lens;
The fourth optical element is a telecentric lens;
Optical scanning device. An optical scanning method for scanning an object with a laser beam,
A first step of emitting laser light from a light source;
A second step of extending the laser light emitted from the light source in the X-axis direction orthogonal to the optical axis, but not extending in the Y-axis direction orthogonal to the optical axis and the X-axis direction;
A third step of changing the traveling direction of the laser light and causing the laser light to be incident on the inner peripheral surface of the rotationally driven cylindrical shielding plate;
A fourth step of emitting laser light incident on the inner peripheral surface of the shielding plate to the outside of the shielding plate through an opening provided on the inner peripheral surface;
A fifth step of collimating the laser beam that has passed through the opening in the X-axis direction;
A sixth step of condensing the laser light collimated in the fifth step in the X-axis direction and the Y-axis direction,
The shielding plate is driven to rotate about an axis parallel to the optical axis;
Optical scanning method. An optical scanning device that scans an object with laser light, and a detection device that detects the presence or absence of foreign matter on the surface of the object based on laser light reflected by the object or transmitted through the object. A surface inspection device comprising:
The optical scanning device includes:
A light source that emits laser light;
A first optical element that expands the laser light emitted from the light source in the X-axis direction orthogonal to the optical axis, but does not extend in the Y-axis direction orthogonal to the optical axis and the X-axis direction;
A second optical element that converts the traveling direction of the laser light emitted from the first optical element and enters the inner peripheral surface of the rotation shielding plate;
An opening that is provided in the rotation shielding plate and that crosses the optical path of the laser light as the rotation shielding plate rotates;
A third optical element that is provided on the outer peripheral surface of the rotary shielding plate and parallelizes the laser light that has passed through the opening in the X-axis direction;
A fourth optical element for condensing the laser light emitted from the third optical element in the X-axis direction and the Y-axis direction,
The rotation shielding plate has a cylindrical shape surrounding the second optical element, and rotates around an axis parallel to the optical axis.
Surface inspection device.

Images