WO2006112315A1

WO2006112315A1 - Visual inspection device and method

Info

Publication number: WO2006112315A1
Application number: PCT/JP2006/307722
Authority: WO
Inventors: Yuji Ono
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2005-04-14
Filing date: 2006-04-12
Publication date: 2006-10-26
Also published as: KR101204585B1; CN101080608A; JPWO2006112315A1; DE112006000841T5; JP4874103B2; CN100541115C; KR20070120086A

Abstract

A rotary polygon mirror (11) is constituted such that the condensing point of a scanning light flux is deviated in a sub-scanning direction (Y) as it rotates at an isogonal speed and an angle (Ϝ) formed between the rotation axis (11b) and a mirror plane differs from one mirror plane to another, a condensing point position forming optical system (2, 17) is constituted such that the condensing point moves within an inspection range Zr in a height direction Z, and an object of inspection (3) is moved in a sub-scanning direction so that the condensing point deviated in the sub-scanning direction and the height direction in synchronization with the isogonal-speed rotation of the rotary polygon mirror is scanned linearly in the height direction of the object of inspection to complete XYZ scanning, whereby the positional coordinates of the appearance of the object of inspection are obtained by a confocal method to perform visual inspection.

Description

Specification

Appearance inspection apparatus and method

Technical field

[0001] The present invention relates to a visual inspection apparatus and method for an inspection object, and more specifically, spot light (irradiation light) such as a laser, a polygon mirror (hereinafter referred to as a rotating polygon mirror), and a scanning condenser lens. The focus position forming optical system having the illuminating position irradiates and linearly travels on the inspection target, and is reflected by the inspection target and reflected to the mirror surface of the rotary polygon mirror via the focus position forming optical system ( The present invention relates to an apparatus for inspecting the appearance of an object to be inspected by photoelectrically converting the light intensity of incident reflected light and obtaining the position coordinates of the appearance by the principle of confocal method.

[0002] In particular, when performing an appearance inspection of an inspection object at high speed, the confocal relationship of the inspection object can be changed during a linear scanning operation by rotation of a rotary polygon mirror, so that the optical system and the inspection object are heightened. It is a simple configuration that does not need to be moved in the direction.

Background art

[0003] Conventionally, as a method of measuring and inspecting a three-dimensional shape geometrically optically, various light is projected onto an object, and the reflected light is measured and inspected by a photodetector. There are two main methods: a method in which an object is measured with a camera from multiple directions under illumination and a three-dimensional shape is determined by correlation between multiple images.

[0004] The former is further classified into various categories depending on the light projection method, the type of photodetector, and the positional relationship between them, and the confocal light shown in FIG. There is a method that detects the collection state of reflected light by the academic system, searches for the focal position and obtains the height information of the object to be inspected.

In FIG. 11A, the irradiation light emitted from the light source 101 is emitted toward the inspection object 103, that is, in the irradiation direction as indicated by a dotted line, passes through the light separation mirror 104, and is inspected by the condenser lens 121. Light is collected at a light condensing point Pa on the object 103. Of the reflected light reflected at the condensing point Pa on the surface of the inspection object 103, the reflected light reflected in the direction opposite to the irradiation direction (falling light) (Reflected light) again enters the condensing lens 121, is reflected by the light separating mirror 104 in a direction orthogonal to the irradiation direction, enters the reflected light condensing lens 105, and is then shielded by the reflected light condensing lens 105. A condensing point Qa is formed in the minute hole 106, passes through the minute hole in the shielding plate 106, enters the photodetector 107, and the light intensity is photoelectrically converted to the photoelectric conversion signal output la by the photodetector 107. . Here, the condensing point Pa of the irradiation light condensing lens 121 and the condensing point Qa of the reflected light condensing lens 105 (that is, a minute hole in the shielding plate 106) are in an optically confocal relationship.

[0005] When the inspection object 103 moves from the irradiation light condensing point Pa by the movement amount z in the irradiation direction and is located at the position of the inspection object 103-1, it is reflected on the surface of the inspection object 103-1. The reflected light is indicated by a broken line, and the condensing point of the reflected light moves from the point Qa to a point Qa-1 which is separated in a direction approaching the reflected light condensing lens 105. Therefore, the size of the image of the reflected light on the shielding plate 106 is increased, the amount of reflected light collected by the reflected light condensing lens 105 is reduced through the minute holes of the shielding plate 106, and the photoelectric of the photodetector 107 is reduced. The conversion signal output la decreases.

FIG. 11B shows the relationship between the movement amount za of the inspection object 103 and the photoelectric conversion signal output la of the photodetector 107. The photoelectric conversion signal output la becomes the largest at a position of za = 0 where the reflection point of the inspection object 103 coincides with the irradiation light condensing point Pa, and the photoelectric conversion signal output la becomes small when za is away from 0. That is, the irradiation of the inspection object 103 is obtained by driving the inspection object 103 in the irradiation direction or in the opposite direction to the irradiation direction (hereinafter referred to as Z direction) to obtain the movement amount za that maximizes the photoelectric conversion signal output la. The appearance can be inspected by obtaining height information at the light condensing point Pa.

[0007] FIG. 11A shows an example of a method of moving only the inspection object 103, but if the condensing point Pa of irradiation light and the position of the inspection object 103 in the Z direction are changed (hereinafter referred to as Z scanning). The same effect can be obtained. As such a Z-scanning method, it is clear that the method of fixing the inspection object 103 and moving the entire optical system has the same effect as the method of moving only the inspection object 103. Z scanning methods other than those methods are shown in FIGS. 12A and 12B.

FIG. 12A shows a method for realizing Z scanning by moving only the irradiation light condensing lens 121 in the optical system in the Z direction to move the irradiation light condensing point Pa to the point Pa-1. Yes. This method is effective when the incident light incident on the irradiation light condensing lens 121 is close to parallel light, and the moving animal is only the irradiation light condensing lens 121, and the irradiation light condensing lens 121 is usually lightweight. of Thus, high-speed measurement and mechanism simplification can be achieved (see, for example, Patent Document 1).

FIG. 12B shows that the irradiation light condensing lens 121 and the inspection object 103 are inserted by inserting a parallel glass 110 having a thickness ta and a refractive index n between the irradiation light condensing lens 121 and the inspection object 103. This shows a method of realizing Z-scanning by changing the optical distance da between and, and moving the irradiation light focusing point Pa to point Pa-2. In this method, the disk in which the plurality of parallel glasses are arranged is rotated at high speed so that a plurality of parallel glasses having different thicknesses or refractive indexes are sequentially inserted between the irradiation light condensing lens 121 and the inspection object 103. By doing so, it is possible to achieve high-speed scanning of Z scanning (see, for example, Patent Document 2).

[0010] In addition, the reflected light from the inspection object 103 is branched into a plurality of light by a plurality of light separation mirrors 104, and each branched reflected light is installed at a position where the distance from the reflected light collecting lens 105 is different. By simultaneously measuring the photoelectric conversion signal output Ia of each branched reflected light by a plurality of shielding plates 106 and photodetectors 107, an optical system equivalent to the Z scanning method is formed, and the time required for Z scanning ( For example, it is possible to realize faster Z-scanning by omitting the time for moving the inspection object 103 or moving the irradiation light condensing lens 121 (see, for example, Patent Document 3).

As described above, by performing Z scanning in the confocal method, it is possible to obtain the height information of the inspection object 103 at the irradiation light condensing point Pa. Further, the inspection object 103 is moved in the X direction and the Y direction orthogonal to each other and orthogonal to the Z direction, and the position of the irradiation light condensing point Pa with respect to the inspection object 103 is changed to the X direction ( (Hereinafter referred to as “X scanning”), and the position of the irradiation light condensing point Pa with respect to the inspection object 103 is changed in the Y direction (hereinafter referred to as “Y scanning”). ) And the appearance can be inspected (see, for example, Patent Document 1). Of course, even if the inspection object 103 is fixed and the entire optical system is moved in the X and Y directions, or the inspection object 103 is moved in the X or Y direction, the entire optical system is moved in the X or Y direction. Even if it is moved in the direction, it is possible to inspect the appearance by obtaining the position coordinates of the inspection object 103 in the same manner.

[0012] As means for increasing the speed of X scanning and Y scanning, there is a method for realizing X scanning and Y scanning by providing a new optical system for scanning irradiation light in the optical system (for example, a patent). (Ref. 4). In addition, there is a method in which a number of confocal optical systems including a light source 101 to a light detector 107 are arranged in the measurement optical system, and multiple points are simultaneously measured in an XY grid (see, for example, Patent Document 5). See).

[0013] Patent Document 1: Japanese Patent Laid-Open No. 62-245949

Patent Document 2: Japanese Patent Laid-Open No. 9-126739

Patent Document 3: Japanese Patent Laid-Open No. 5-40035

Patent Document 4: JP-A-3-231105

Patent Document 5: Japanese Patent Laid-Open No. 9-257440

Disclosure of the invention

Problems to be solved by the invention

However, in the conventional configuration, separate methods are used for the XY scan and the Z scan, and if XY scan and z scan are to be realized simultaneously in order to achieve high-speed scanning, the number of parts is reduced. As a result, the structure became more complicated, and there were problems such as increased costs, reduced reliability, and increased size.

[0015] In order to solve the conventional problems, the present invention provides an appearance inspection apparatus and method that realizes a high-speed appearance inspection by a simple mechanism by incorporating Z scanning in an XY scanning mechanism. With the goal.

Means for solving the problem

In order to achieve the above object, the present invention is configured as follows.

According to the first aspect of the present invention, a light source that emits a luminous flux;

It has at least three mirror surfaces on the outer periphery, and is arranged so as to be rotatable at an equiangular speed around the rotation axis. The light beam emitted from the light source is deflected toward the inspection object by the respective mirror surfaces, and is rotated by the rotation. A rotating polygon mirror capable of scanning the light beam linearly in the main scanning direction;

By rotating the rotating polygon mirror, the light beam deflected and scanned by the respective mirror surfaces of the rotating polygon mirror is condensed at the condensing point, and the condensing point is orthogonal to the main scanning direction of the inspection object. A condensing point position forming optical system that moves the inspection range in the height direction and the condensing point position forming optical system that is reflected by the inspection object after passing through the condensing point position forming optical system Via the mirror surface of the rotary polygon mirror A photodetector that photoelectrically converts a light intensity of reflected light that depends on a distance between the condensing point and a reflection point of the light flux on the inspection object into a photoelectric conversion signal output; and An inspection object moving device that moves the inspection object in a sub-scanning direction perpendicular to the main traveling direction and the height direction in synchronization with the rotation of the equiangular velocity of a polygon mirror;

A calculation unit that obtains position coordinates of the appearance of the inspection object based on the photoelectric conversion signal output of the reflected light photoelectrically converted by the photodetector, and inspects the appearance of the inspection object; Prepared,

The rotating polygon mirror is a mirror surface angle that is an angle formed by a rotation axis of the rotating polygon mirror and the mirror surface so that the condensing point of the light beam is shifted in the sub-scanning direction with the rotation of the equiangular velocity. Are configured differently for each mirror surface,

The inspection object moving device is moved in the inspection range in the height direction by the focusing point position forming optical system while the rotary polygon mirror makes one rotation at the equiangular velocity, and the And moving the inspection object in the sub-scanning direction so that the condensing point shifted in the sub-scanning direction by the mirror surface is linearly scanned in the height direction of the inspection object Before the rotating polygon mirror starts one more rotation at the equiangular speed, the inspection object is moved in the sub-scanning direction, and the linear scanning in the main scanning direction and the height in the height direction are performed. Appearance inspection by moving the condensing point in the inspection range is configured to perform appearance inspection at the one rotation of the rotary polygon mirror and at different parts on the inspection object! A feature visual inspection apparatus is provided.

According to the second aspect of the present invention, the condensing point position forming optical system is disposed such that an optical axis is inclined with respect to a direction orthogonal to the rotational axis of the rotary polygon mirror, A scanning condensing lens that condenses the light beam deflected and scanned by the respective mirror surfaces of the rotary polygon mirror at the condensing point, and the condensing point moves linearly in the main scanning direction; The appearance inspection apparatus according to the first aspect is provided, wherein the inspection range in the height direction is moved.

[0018] According to the third aspect of the present invention, the condensing point position forming optical system comprises:

The optical axis is arranged so as to be parallel to the direction orthogonal to the rotation axis of the rotary polygon mirror. A scanning condensing lens that condenses the light beam deflected and scanned by the respective mirror surfaces of the rotating polygon mirror at the condensing point;

An entrance surface and an exit surface are arranged between the scanning condenser lens and the inspection object so as to be parallel to the main scanning direction, and the exit surface force is refracted by the incident light from the entrance surface. With an exiting prism,

The light beam that has passed through the scanning condensing lens is incident from the incident surface of the prism, bent and emitted from the exit surface, and the condensing point moves linearly in the main scanning direction. The appearance inspection apparatus according to the first aspect is provided, wherein the inspection range in the height direction is moved.

[0019] According to the fourth aspect of the present invention, the data storage further stores the photoelectric conversion signal output of the reflected light output from the photodetector during at least one rotation of the rotary polygon mirror. Part

The arithmetic unit obtains a position coordinate of an appearance of the inspection object by obtaining a position in the height direction of the inspection object based on the photoelectric conversion signal output stored in the data storage unit, and the inspection An appearance inspection apparatus according to the first aspect, characterized in that the appearance of an object is inspected.

[0020] According to the fifth aspect of the present invention, the rotating polyhedron has at least three mirror surfaces on the outer peripheral portion, and has a mirror surface angle that is an angle formed between the rotation axis and the mirror surface, and is different for each mirror surface. In the deflection scanning, the mirror is rotated at an equiangular speed around the rotation axis, and the light beam emitted from the light source to the mirror surface is deflected toward the inspection object while being linearly scanned in the main scanning direction. The main scanning of the inspection object is performed by condensing the light beam deflected and scanned by the respective mirror surfaces of the rotary polygon mirror at the condensing point by the condensing point position forming optical system. The condensing points shifted in the inspection range in the height direction orthogonal to the direction and shifted in the main scanning direction and the sub-scanning direction orthogonal to the height direction by the respective mirror surfaces having different mirror angles. Is the height of the inspection object The inspection object is moved in the sub-scanning direction so as to be scanned in a straight line in the direction, and reflected by the inspection object moving in the sub-scanning direction, and the condensing point position forming optical system Via the light intensity of the reflected light deflected to the mirror surface of the rotary polygon mirror Then, the light intensity depending on the distance between the condensing point and the reflection point of the inspection object of the light beam is photoelectrically converted into a photoelectric conversion signal output, and based on the photoelectric conversion signal output, the inspection is performed. Obtaining the position coordinates of the appearance of the object, inspecting the appearance of the inspection object, and then inspecting the inspection object in the sub-scanning direction before the rotary polygon mirror starts one more rotation at the equiangular speed Move things,

Next, an appearance inspection by the linear scan in the main scanning direction and a movement of the condensing point in the inspection range in the height direction, an appearance inspection in the one rotation of the rotary polygon mirror and the inspection object Provide a visual inspection method characterized by being performed in different parts above

[0021] According to the sixth aspect of the present invention, in the deflection scanning, the optical system for forming the condensing point position is configured and the optical axis is perpendicular to the rotational axis of the rotary polygon mirror. The condensing point is as described above while the light beam deflected and scanned by the respective mirror surfaces of the rotary polygon mirror is condensed on the condensing point by the scanning condensing lens arranged to be inclined. The visual inspection method according to the fifth aspect, characterized in that the light is condensed so as to move in the inspection range in the height direction while moving linearly in the main scanning direction.

[0022] According to a seventh aspect of the present invention, in the deflection scanning, the condensing point position forming optical system is configured and an optical axis is parallel to a direction orthogonal to the rotational axis of the rotary polygon mirror. The light beam deflected and scanned by the respective mirror surfaces of the rotary polygon mirror is condensed at the light condensing point by the scanning condensing lens arranged to be

A prism that constitutes the condensing point position forming optical system and is arranged between the scanning condensing lens and the inspection object so that an incident surface and an exit surface are parallel to the main scanning direction. The light beam that has passed through the scanning condensing lens enters from the incident surface of the prism, is refracted and exits from the exit surface, and the condensing point moves linearly in the main scanning direction. The visual inspection apparatus according to the fifth aspect is characterized in that the light is condensed so as to move in the inspection range in the height direction.

The invention's effect

[0023] According to the first or fifth aspect of the present invention, the rotating polygon mirror is moved at an angle formed by the rotation axis and the mirror surface so that the condensing point of the scanning light flux is displaced in the sub-scanning direction as the angular velocity is rotated. A specular angle Is configured to be different for each mirror surface, and the condensing point position forming optical system is configured so that the condensing point moves in the inspection range in the height direction, so that the rotating polygon mirror can rotate at an equal angular velocity. Synchronously, the condensing point that has been moved in the inspection range in the height direction and shifted in the sub-scanning direction is scanned linearly in the height direction of the inspection object. Since the inspection object is moved in the sub-scanning direction, scanning of the inspection object in the main scanning direction (X scanning) is performed by one mirror surface during the rotation operation of the rotary polygon mirror, The mirror surfaces with different mirror angles are switched during one rotation of the rotary polygon mirror to perform a height scan (Z scan), and the rotation is performed while moving the inspection object in the sub-scan direction. Side running by rotating the polygon mirror multiple times Scan direction (Y scan) can be performed. In other words, Z scanning can be incorporated in the XY scanning mechanism, and high-speed visual inspection can be realized by such a simple mechanism.

[0024] When the appearance inspection of the inspection object is performed according to the first aspect of the present invention, the position coordinates of the appearance of the inspection object are set, for example, by two points in the main scanning direction (three-dimensional). At least two points are required to determine the position coordinates of the appearance. Three points or more are preferable for increasing the X resolution), and two points in the sub-scanning direction (to obtain the position coordinates of the three-dimensional appearance) A force that requires two points is recommended. To increase the Y resolution, three or more points are preferable), and a total of three points in the height direction (minimum of three depending on the number of mirrors of the rotating polygon mirror) (2 X 2 X 3 = ) 12 points By finding it, the appearance of the inspection object can be inspected in three dimensions.

On the other hand, in Patent Document 1, in order to perform Z scanning, the irradiation light condensing lens is moved in the height direction (Z direction) separately from the driving mechanism for performing XY scanning. In addition, if the irradiation light condensing lens is moved in the height direction, vibration or the like may occur when the lens is stopped, which may reduce the inspection accuracy. According to the first or fifth aspect of the present invention, since a drive mechanism for moving the irradiation light collecting lens or the like in the height direction is not required, it is possible to prevent the inspection accuracy from being lowered.

Further, in Patent Document 3, in order to perform Z scanning, it is necessary to arrange a plurality of light separating mirrors, shielding plates, and photodetectors. According to the first or fifth aspect of the present invention, since only one light separation mirror, one shielding plate, and one light detector are required, an increase in the number of components is suppressed to prevent an increase in cost and an increase in size. be able to. Brief Description of Drawings

These and other objects and features of the invention will become apparent from the following description taken in conjunction with the preferred embodiment of the accompanying drawings. In this drawing,

FIG. 1A is a schematic perspective view showing configurations of an optical system and a mechanism system of an appearance inspection apparatus according to a first embodiment of the present invention.

[FIG. 1B] FIG. 1B is a partially enlarged perspective view of FIG.

FIG. 2 is a schematic view of the configuration of the optical system of the appearance inspection apparatus and method according to the first embodiment of the present invention as viewed from the sub-scanning direction;

FIG. 3A is a diagram for explaining the effect of the mirror angle of the rotary polygon mirror of the visual inspection apparatus and method according to the first embodiment of the present invention;

FIG. 3B is a diagram for explaining the effect of the installation angle of the scanning condensing lens of the appearance inspection apparatus and method according to the first embodiment of the present invention;

FIG. 4A is a side view showing a change in the mirror angle of the rotary polygon mirror of the visual inspection apparatus according to the first embodiment of the present invention;

FIG. 4B is a cross-sectional view showing a change in the mirror angle of the rotary polygon mirror of the visual inspection apparatus according to the first embodiment of the present invention;

FIG. 4C is a perspective view showing an example of the shape of the rotary polygon mirror of the appearance inspection apparatus according to the first embodiment of the present invention.

[FIG. 5A] FIG. 5A is a side view showing a change of the irradiated light condensing point by the mirror surface of the appearance inspection apparatus and method in the first embodiment of the present invention,

[FIG. 5B] FIG. 5B is a perspective view showing a change of the irradiated light collecting point by the mirror surface of the appearance inspection apparatus and method according to the first embodiment of the present invention;

[FIG. 6A] FIG. 6A is a schematic perspective view showing a configuration for explaining a sending operation and data processing in the sub-scanning direction of the appearance inspection apparatus according to the first embodiment of the present invention. [FIG. 6B] Figure 6B is a partially enlarged view of Figure 6A.

[FIG. 7A] FIG. 7A is a diagram showing the control of the feed amount of the inspection object to the position in the sub-scanning direction by the table feeding device of the appearance inspection apparatus and method according to the first embodiment of the present invention. [FIG. 7B] FIG. 7B is an inspection target of the visual inspection apparatus and method according to the first embodiment of the present invention. It is a diagram showing the principle of YZ scanning for objects,

[FIG. 8 (b)] FIG. 8 (b) is a schematic diagram of the storage contents of the data storage unit of the appearance inspection apparatus and method according to the first embodiment of the present invention.

[FIG. 8A] FIG. 8A is a diagram showing the principle of the calculation method of the appearance position coordinate calculation unit of the appearance inspection apparatus and method according to the first embodiment of the present invention.

[FIG. 8C] FIG. 8C is a diagram showing an example of eyelid scanning on an inspection object of the appearance inspection apparatus and method according to the first embodiment of the present invention;

FIG. 8D is a schematic diagram showing an example of the contents stored in the data storage unit of the visual inspection apparatus and method according to the first embodiment of the present invention;

[FIG. 8A] FIG. 8A is a diagram showing an example of a calculation method of the appearance position coordinate calculation unit of the appearance inspection apparatus and method according to the first embodiment of the present invention.

[FIG. 9B] FIG. 9B is a schematic view of the configuration of the optical system of the visual inspection apparatus and method according to the second embodiment of the present invention viewed from the sub-scanning direction.

[FIG. 9B] FIG. 9B is a schematic view of the configuration of the optical system of the visual inspection apparatus and method according to the second embodiment of the present invention as seen from the main scanning direction.

FIG. 10A is a diagram for explaining the action of the long prism of the appearance inspection apparatus and method according to the second embodiment of the present invention;

[FIG. 10B] FIG. 10B is a diagram for explaining the movement of the light collection point by the long prism of the visual inspection apparatus and method according to the second embodiment of the present invention;

[FIG. 11A] FIG. 11A is a configuration diagram of an optical system of a conventional confocal appearance inspection apparatus. [FIG. 11B] FIG. 11B is a schematic diagram of the photoelectric detector 7 in the conventional confocal appearance inspection apparatus. It is a diagram showing the positional relationship between the conversion signal output I and the inspection object,

[FIG. 12A] FIG. 12A is a diagram showing eyelid scanning example 1 (movement of a condensing lens) in a conventional confocal appearance inspection apparatus.

FIG. 12B is a diagram showing eyelid scanning example 2 (insertion of parallel glass) in a conventional confocal appearance inspection apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

Before continuing the description of the present invention, the same reference numerals are used for the same parts in the accompanying drawings. Is attached.

Hereinafter, an appearance inspection apparatus and method according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0028] << First Embodiment >>

FIG. 1A is a schematic perspective view showing a configuration of an optical system and a mechanism system of an appearance inspection apparatus according to the first embodiment of the present invention, and FIG. 1B is a partially enlarged view of FIG. It is a perspective view. FIG. 2 is a schematic view of the same optical system as viewed from the sub-scanning direction.

First, the basic configuration of the appearance inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1A and 1B.

The appearance inspection apparatus according to the first embodiment of the present invention includes a light source 1, a rotating polygon mirror 11, a motor 11a, a scanning condensing lens 2 that constitutes an example of a condensing point position forming optical system, Separating mirror 4, reflected light collecting lens 5, shielding plate 6, photodetector 7, table feeding device 12 as an example of an inspection object moving device, and data storage unit 13 as an example of a storage unit A calculation unit 14, an output unit 15, and a control unit 16.

The light source 1 emits a light beam such as a laser toward the rotary polygon mirror 11 as irradiation light.

The rotating polygonal mirror 11 is formed in the shape of a polygonal cylinder (eg, hexagonal prism) and has a plurality of mirror surfaces 1 lc (reflective surfaces) with different mirror angles on the outer periphery, and is rotated at a constant angular velocity in one direction by a motor 1 la. It is configured to be possible. The rotating polygonal mirror 11 directs the irradiation light of the light source 1 to the inspection object 3 (for example, an electronic component mounted on the substrate or a cream solder that joins the substrate and the electronic component) with each mirror surface 11c (height). It can be deflected in the direction Z (upward and downward in Fig. 1) and in the opposite direction (downward and downward in Fig. 1).

The scanning condensing lens 2 is disposed between the rotating polygonal mirror 11 and the inspection object 3, and condenses the irradiation light deflected by the rotating polygonal mirror 11 at a nearby point P on the inspection object 3 (hereinafter referred to as “scanning focusing lens”). The condensing point where the irradiation light deflected by the rotating polygonal mirror 11 is condensed by the scanning condenser lens 2 is referred to as an irradiation light condensing point).

[0031] The light separation mirror 4 has a rectangular plate shape, is disposed between the light source 1 and the rotary polygon mirror 11, and is condensed near the inspection object 3 by the scanning condenser lens 2. Reflected in height direction Z in 3 The reflected light that travels in the reverse path to the irradiation light and returns to the light source 1 is separated from the irradiation light of the light source 1, that is, the force on the irradiation path of the irradiation light of the light source 1 is also separated, and the disk-shaped reflected light collection is performed. The light is incident on the lens 5.

The reflected light condensing lens 5 condenses the reflected light separated by the light separating mirror 4 in the vicinity of a minute hole formed in the shielding plate 6 having a rectangular plate shape.

The light detector 7 photoelectrically converts the light intensity of the reflected light incident through the minute hole of the shielding plate 6 into a photoelectric conversion signal output I.

[0032] The table feeder 12 includes a drive shaft 12a arranged to extend in the height direction Z and the sub-scanning direction Y orthogonal to the main scanning direction X, and the drive shaft 12a screwed to the drive shaft 12a. The nut member 12b that can move forward and backward on the drive shaft 12a by rotating forward and backward, and the rectangular plate-shaped tape 12c that is fixed to the nut member 12b and can hold the substrate 3A on which the inspection object 3 is placed And a drive motor 12d for rotating the drive shaft 12a in the forward and reverse directions. In the table feeder 12, the drive motor 12d is driven by the control unit 16, the drive shaft 12a rotates forward and backward, and the nut member 12b and the table 12c fixed to the nut member 12b move forward and backward in the Y direction. Thus, the inspection object 3 is configured to be movable back and forth in the Y direction.

The control unit 16 is connected to the light source 1, the photodetector 7, the motor lla, the drive motor 12 d, and the data storage unit 13, and based on an operation program stored in advance in the data storage unit 13 1. Controls the driving of the photodetector 7, the motor 11a, and the driving motor 12d.

The data storage unit 13 stores the operation program of each device and also stores the photoelectric conversion signal output I of the reflected light that has been photoelectrically converted by the photodetector 7 and output.

The calculation unit 14 includes an extraction unit 14a connected to the data storage unit 13 and an appearance position coordinate calculation unit 14b connected to the extraction unit 14a, and outputs a photoelectric conversion signal of reflected light stored in the data storage unit 13. It is configured to obtain the position coordinates of the appearance of the inspection object 3 based on the I-axis.

The output unit 15 is configured by, for example, a display, is connected to the appearance position coordinate calculation unit 14b, and outputs and displays the position coordinates of the appearance of the inspection object 3 calculated by the appearance position coordinate calculation unit 14b.

[0034] The visual inspection apparatus according to the first embodiment of the present invention has a basic configuration as described above. It is.

The detailed configuration of the appearance inspection apparatus according to the first embodiment of the present invention will be described below along with the operation.

In FIG. 1A, FIG. IB, and FIG. 2, first, the controller 16 controls the drive so that a light beam is emitted from the light source 1. The light beam emitted as the irradiation light from the light source 1 is deflected by one mirror surface 11c of the rotary polygon mirror (polygon mirror) 11, enters the scanning condenser lens 2, is emitted as a convergent light beam, and is inspected 3 It becomes the scanning beam that is focused at the point P near the top. Here, the light beam emitted from the light source 1 is driven by the control unit 16 and the rotation of the rotary polygonal mirror 11 changes the angle of the scanning light beam incident on the scanning condensing lens 2, thereby collecting the irradiated light. The light spot P moves continuously from point P1 to point P2 to point P3, and scans the inspection object 3 linearly in the main scanning direction X (hereinafter referred to as X scanning). Of the reflected light that is irradiated onto the inspection object 3 and reflected by the inspection object 3, the reflected light (epi-reflection light) in the height direction Z (both in the scanning beam direction!) Is reflected by the scanning condenser lens 2. After passing through the rotating polygon mirror 11 and passing a path opposite to the scanning light beam, and separated from the scanning light beam by the light separation mirror 4, the same confocal optical system (reflected light lens 5 and shield) as in the conventional example is used. It reaches the photodetector 7 via the plate 6). In this way, by rotating the rotating polygonal mirror 11, the photoelectric conversion signal output I obtained by the photodetector 7 can be obtained from the light intensity of the epi-reflection light on the scanning line of the inspection object 3. .

At this time, the control unit 16 controls the driving of the driving motor 12d of the table feeding device 12 in synchronization with the rotation of the rotary polygon mirror 11, and the inspection object 3 held on the table 12c is the main object. Move in the direction perpendicular to both scanning direction X and height direction Z (hereinafter referred to as sub-scanning direction Y).

Note that the rotational speed of the rotary polygon mirror 11 is generally constant, and in order to make the moving speed (scanning speed) of the scanning light flux in the main scanning direction X constant, the scanning condenser lens 2 is shown in FIG. As shown in Fig. 4, the relationship between the change angle of the incident angle Θ (twice the change angle δ of the deflection angle by the rotating polygonal mirror 11) and the scan position change X is a linear proportional relationship with the focal length f as the proportional coefficient ( X = f X Θ dd

F 0 lens is generally used. In the first embodiment, the following

The scanning condenser lens 2 is an fΘ lens. In FIG. 2, as an example, the force point P2 described so that the point P2 is located near the center of the point P1 and the point P3 is scanned from the point P1 to the point P3. It is located at an arbitrary position on the range.

FIG. 3A and FIG. 3B are views of the optical system in the first embodiment, viewed from the main scanning direction X, and explain the effects of the optical system.

[0038] In FIG. 3A, when the angle λ (hereinafter referred to as the mirror angle measurement) between the mirror surface 11c of the rotating polygon mirror 11 and the rotation axis l ib of the rotating polygon mirror 11 is λ = α / 2, the rotating polygon mirror 1 1 The angle of the light beam 1 of the light source 1 deflected by the reflecting surface and the plane perpendicular to the rotation axis l ib of the rotary polygon mirror 11 is oc, and as a result, the condensing position of the scanning light beam on the inspection object 3 is Due to the fΘ characteristic of the scanning condensing lens 2, the point P shifted by y = f X α in the sub-scanning direction Y as shown by the dotted line in FIG. — 2 In addition, as shown in FIG.

d

If the angle between the optical axis of the condenser lens 2 and the plane orthogonal to the rotational axis l ib of the rotary polygon mirror 11 is β, the condenser plane of the scanning condenser lens 2 is the rotational axis l ib of the rotary polygon mirror 11 Since the angle is β, the irradiation light condensing point of the scanning light beam is y = f X α in the sub-scanning direction Ρ and the height direction with respect to the irradiation light condensing point α when α = β = 0. A point P— 1 that is shifted from Z by z = f X a X tan (j8)

d d

Become. The mirror angle of the rotating polygonal mirror 11 is almost constant even if the rotation angle of the rotating polygonal mirror 11 changes during scanning with the same mirror surface 1 1c.

dj

This z is almost constant. In other words, with this optical system configuration, the mirror surface d of the rotating polygon mirror 11

By angling, the entire scanning line formed by the trajectory of the irradiation light condensing point P of the scanning light beam can be shifted in the height direction Z with respect to the inspection object 3.

[0039] FIGS. 4A to 4C show the effects of changing the angle of each mirror surface of the rotating polygon mirror 11. FIG. As shown in FIG. 4A, if the mirror surface angle of the rotating polygon mirror 11 having n mirror surfaces 11c is changed for each mirror surface 11c, the height of the irradiation light focal point P is increased during one rotation of the rotating polygon mirror 11. The z-direction position z can be changed n times. That is, the running line by the first mirror surface 1 di ii lc (i is an arbitrary mirror surface number among n and an integer number between l and n) with a mirror surface angle (= «/ 2) Sub-scanning direction position y and height direction position z are y = f X a, z = f

di di di i di

X a X tai iS), and the rotation of the rotating polygonal mirror 11 changes n times from the sub-scanning direction position y and the height direction i di position z force = l to n. In other words, due to the rotation of the rotating polygonal mirror 11, the inspection object di

It is possible to perform X scan and YZ scan on the object 3 at the same time.

[0040] In FIG. 4C, as an example of the shape of the rotating polygonal mirror 11, the number of mirror surfaces is six (in other words, the mirror A perspective view in the case where the surface number i is 1 to 6) and each mirror surface angle = α / 2) increases in proportion to the surface number i. In addition, as a comparative example, the case where the mirror angle of the rotating polygon mirror l lz is all 0 (that is, a hexagonal column because it is parallel to the rotation axis) is indicated by a two-dot chain line. As shown in Fig. 4C, the rotating polygonal mirror 11 gradually mirrors the first mirror surface 11c force through the sixth mirror surface 11c.

1 6

The angle of lc is changing, and in Fig. 4C, the first mirror surface 11c to the third mirror surface 11c are downward.

13

4th mirror surface 11c force The 6th mirror surface 11c is upward. Since each mirror surface 11c is a plane,

4 6

There is a cross section that combines two triangles at the boundary with the surface, especially the first mirror surface 11c and the sixth mirror surface 11c.

The angle difference of 16 is the largest, so the boundary cross section is also the largest. In other words, when the angle difference between adjacent mirror surfaces excluding between the first mirror surface 11c and the sixth mirror surface 11c is taken,

1 6

The timing is as follows.

[0041] λ = (ί-3.5) Χ ά λ

Where i is the mirror surface number and is an integer between 1 and 6, and the mirror surface angle of the first mirror surface 11c is 2.5 X d

1 1

The mirror surface angle of the sixth mirror surface 11c is +2.5 X d, and the first mirror surface 11c and the sixth mirror surface 11c

6 6 1 6 The angle difference is 5 X d.

[0042] Hereinafter, unless otherwise specified, the rotating polygon mirror 11 will be described as having the shape shown in FIG. 4C (the number of mirror surfaces is 6, and the angle change d λ between adjacent surfaces is constant).

Note that the number of mirror surfaces of the rotating polygon mirror 11 should be at least three. However, the larger the number of mirror surfaces, the more the number of mirror surfaces increases, so that the irradiation light condensing point ずら is shifted in the main driving direction X and the appearance inspection of the inspection object 3 is performed. This is preferable because it can increase the number of sample points of the position coordinates and improve the appearance inspection accuracy.

In the above, the angle of the mirror surface 11c gradually increases from the first mirror surface 11c force to the sixth mirror surface 11c.

1 6

For example, the rotating polygonal mirror 11 is configured so that the angle of the mirror surface 11c changes as follows: + 1 °, + 0.5 °, 0 °, —0.5 ° —1 °. Is not limited to this. For example, even if the mirror surface angle is randomly changed to + 1 °, -0.5 °, 0 °, -1 °, + 0.5 °, the same effect as the above configuration can be obtained. it can.

[0043] The state of YZ scanning of the scanning line by the rotation of the rotary polygon mirror 11 will be described in detail below with reference to FIGS. 5A and 5B. FIG. 5A is a view from the same main scanning direction X as FIG. 3B. Here, the rotating polygon mirror 11 starts the deflection operation of the light beam of the light source 1 from the first mirror surface 11c. Thus, the rotational drive is controlled by the controller 16. The rotating polygon mirror 11 deflects the light beam from the light source 1 in the order of the first mirror surface 11c force and the sixth mirror surface 11c by rotating once.

1 6

[0044] When the mirror surface 11c that deflects the light beam from the light source 1 of the rotating polygon mirror 11 is changed from the first mirror surface 11c to the sixth mirror surface 11c by the rotating operation of the rotating polygon mirror 11, the position of the irradiation light condensing point But

1 6

It changes 5 times from point Px to point Px (Note that point P shown in Fig. 5A has a mirror angle of 0 °, that is,

1 6

This is the irradiation light condensing point when the mirror surface 1 lc of the rotating polygon mirror 11 is parallel to the rotation axis 1 lb). Point Px to Point Px and Point P are on a plane that makes an angle | 8 with the plane 31 perpendicular to the scanning beam, and point P

1 6

Is the intersection with plane 31. Here, the plane 31 is a plane (virtual inspection reference plane) passing through the middle (for example, the center) of the inspection range Zr in the height direction Z preset for the inspection object 3. The inspection range Zr in the height direction Z is higher than the uppermost part of the inspection object 3 in order to inspect the entire inspection object 3, from the same position as the lowermost part of the inspection object 3, or from the lowermost part. Low, preferably set to span the position.

As shown in FIG. 4C, the mirror surface angle of the rotating mirror 11 increases in proportion to the mirror surface number i.

di and height direction position z

Each di is as follows.

[0045] y = fX a = (i-3.5) XfXda

di i

z = f X a Xtan (j8) = (i-3.5) Xf Xda Xtan (j8)

di i

Since d ひ = 2Xd is a constant value, the sub-scanning direction position y and height di direction position _Z di of each irradiation light condensing point change in proportion to the mirror surface number i, and the change interval is constant. The sub-scanning direction Y force Xda and the height direction Z force ¾ Xda Xtan (j8).

FIG. 5B shows a state similar to FIG. 5A in a perspective view. However, in order to show the linear scanning operation by the rotating operation of the rotating polygon mirror 11, the irradiation light condensing point at the start of scanning is P1, and the irradiation light condensing point at the end of scanning is P3 (i is the surface number). I = l ~ 6). That is, the point Px in FIG. 5A indicates the entire locus of the irradiation light collecting point in the linear scan between the points P1 and P3 in FIG. 5B, and the same applies to the point Px to the point Px (however, the point Px As mentioned above

2 6

The locus of the irradiation light condensing point of the linear scanning from the cage points P1 to P3 is shown).

Next, the change with time of the position of the irradiation light condensing point due to the rotation of the rotating polygonal mirror 11 will be described below. First, when the light beam of the light source 1 starts to be reflected by the first mirror surface 11 due to the rotation of the rotating polygon mirror 11, scanning starts at the point P1, and linear scanning is performed up to the point P3. Subsequently, when the surface that reflects the luminous flux of the light source 1 is switched to the second mirror surface 11c by the rotation of the rotating polygon mirror 11, scanning is performed at the point P1.

2 2 Starts and performs a linear scan to point P3. Hereinafter, the light from light source 1 is rotated by rotating polygon mirror 11.

2

When the reflecting surface of the bundle changes from the third mirror surface 11c to the fourth mirror surface 11c, the irradiation light condensing point is also point P1.

3 6 3 From point P3, point P1 force point P3, point P1 force point P3, changes from point P1 to point P3. here,

3 4 4 5 5 6 6

In FIG. 5B, the point P1 force indicated by the solid arrow is also point P3, and the point P1 force is also from point P3 and point P1.

3 3 4 4 5 Point P3 indicates a linear scan by moving the irradiation light condensing point. Dotted arrows in Figure 5B

Five

Between point P3 and point P1, between point P3 and point P1, and between point P3 and point P1

3 4 4 5 5 6 shows a state in which the irradiation light condensing point does not exist, that is, a state in which linear scanning is not performed.

Furthermore, the rotating polygon mirror 11 makes one rotation, and the sixth mirror surface 11c force the light of the light source 1 on the first mirror surface 11c.

6 1

When the reflecting surface of the bundle is switched and the luminous flux of the light source 1 is reflected again by the first mirror surface 11c and scanning starts, it changes to point P3, point P1, power point P3, point P1, and so on. Start

6, 1 1, 2 1

Thus, the same operation as described above is repeated. Thus, point P1 to point P3 1 in one rotation by the rotating polygon mirror 11

When the irradiation light condensing point moves to 6 and the rotating polygon mirror 1 rotates continuously, point P1

1

~ The same path at point P3 will be scanned repeatedly.

6

[0048] It should be noted that the rotating polygon mirror 11 further rotates from the state of the rotating polygon mirror 11 at the irradiation light condensing point P1, which is the scanning start point, and the change angle δ of the deflection angle of the mirror surface 11c of the rotating polygon mirror 11 Changes, that is, when the position of the light source 1 of the rotating polygon mirror 11 on the same mirror surface 1 lc changes and changes to the irradiation light condensing point P2, the change interval in the main scanning direction X (for example, point P1 (Distance to force point P1) X is the Θθ characteristic force of scanning condenser lens 2 as described above X = f X 2

2d d

X δ = f X Θ. Here, Θ indicates the change angle of the incident angle, and θ = 2Χδ.

[0049] As described above, the angle of each mirror surface 11c of the rotary polygon mirror 11 as shown in Fig. 4C is configured to be different from each other. Linear scanning (X scanning) is performed by changing the position X in the main scanning direction of the irradiation light condensing point by reflecting the light beam.

And rotate the rotating polygonal mirror 11 to switch the mirror surface 1 lc that reflects the luminous flux of the light source 1 to change the position y in the sub-scanning direction and the position z in the height direction, and simultaneously perform two scans (YZ scanning). Can be implemented.

Next, the feeding operation and data processing in the sub-scanning direction Y of the inspection object 3 of the appearance inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 6A and 6B. FIG. 6A is a schematic perspective view showing a configuration for explaining the feeding operation and data processing of the inspection object 3 in the sub-scanning direction Y of the appearance inspection apparatus according to the first embodiment of the present invention. FIG. 6B is a partially enlarged perspective view of FIG. 6A showing the inspection object 3.

[0051] The control unit 16 controls the drive of the drive motor 12a of the table feeder 12, and rotates the drive shaft 12a in synchronism with the start of scanning of each mirror surface 11c of the rotary polygon mirror 11, thereby causing the nut member to rotate. 1 The table 12c fixed to 2b and the nut member 12b is moved in the sub-scanning direction Y, and the inspection object 3 on the substrate 3A held by the table 12c is moved in the sub-scanning direction Y. In addition, the control unit 16 performs the main scanning direction position X of the scanning light beam while the scanning light beam linearly scans the inspection object 3.

At a time interval such that di becomes a constant interval, the photoelectric conversion signal output I of the photodetector 7 is changed for one rotation or more of the rotary polygon mirror 11 (that is, the point P1

1 to point P3

Data is stored in the data storage unit 13 during 6 scans). Further, the control unit 16 extracts the photoelectric conversion signal output I of the photodetector 7 stored in the data storage unit 13 by the extraction unit 14a, and outputs the photoelectric conversion signal output I of the photodetector 7 extracted by the extraction unit 12a. Based on the above, the appearance position coordinate calculation unit 14b calculates the position coordinates of the appearance of the object 3 to be detected.

Next, using FIG. 7A and FIG. 7B, the control of the feed amount Yt of the inspection object 3 in the sub-scanning direction Y by the table feeder 12 and the principle of YZ scanning for the inspection object 3 will be described. I will explain. In FIG. 7A, during one rotation of the rotary polygonal mirror 11 having six mirror surfaces 11c, the position y of the scanning line in the sub-scanning direction changes y, y,. At this time,

di dl d2 d6

The feed amount Yt of the table feeder 12 is synchronized with the scanning operation of each mirror surface 11c of the rotary polygon mirror 11 in the sub-scanning direction position y of the scanning line.

If the same value as the amount of change of di is changed, the inspection object

The scanning line always scans the same position with respect to the position y in the sub-scanning direction.

di

become. That is, when the table feeder 12 is stopped, the irradiation light condensing point moves toward the inspection object 3 as it is directed in the sub-scanning direction Y as shown in FIG. 7A (right diagonally in FIG. 7A). (Downward), but when the inspection object 3 is fed in the sub-scanning direction Y by the table feeder 12, as shown in Fig. 7B, it is in the direction opposite to the height direction Z (downward in Fig. 7B) Run I will be jealous. As described above, since the increment of the sub-scanning direction position y is constant at f X da when the mirror surface l ie that deflects the light beam of the light source 1 of the rotating polygon mirror 11 is switched, the feed amount Yt is also equal.

di

When the constant increment f X d a is changed five times from Yt to Yt, the inspection object 3 also becomes the position of the inspection object 3—1.

1 6

The position changes to the position of the inspection object 3-6. On the other hand, the height direction position z of the irradiation light condensing point of the scanning line changes five times as described above with z, ζ, .. ζ and a constant interval f X da Xtan (| 8) di dl d2 d6

The

[0053] By controlling the feed amount Yt of the table feeder 12 as described above, the irradiation light condensing point is parallel to the height direction Z with respect to the inspection object 3 while the rotary polygon mirror 11 is rotated once. Can be changed to achieve Z-scan.

When the driving motor 12a of the table feeder 12 and the motor 11a of the rotary drive mirror 11 are further driven in synchronization, the rotary polygon mirror 11 enters the second rotation. That is, the rotating polygonal mirror 11 sequentially reflects the light beam of the light source 1 by the first mirror surface 11c and the sixth mirror surface 11c, and again the first mirror.

1 6

While being reflected by the surface 11c, the table feeder 12 feeds the inspection object 3 in the sub-scanning direction Y at a constant feeding interval f x da. As a result, the inspection object 3 is located at the position of the inspection object 3-7, and the irradiation light condensing point is located in the height direction Z at the height direction position z. Sand dl

In other words, the irradiation light condensing point is at the height direction position z.

dl force is also in the height direction z

While changing to d6 and changing again to the height position z, the table feeder 12 moves the inspection object 3 to the sub dl.

Move in the scanning direction Y by the scanning interval Υρ (= Υ resolution) = 6 X f X d a and move it to the position of the inspection object 3-7.

FIG. 7B shows changes in the height direction Z and the sub-scanning direction Y of the irradiation light condensing point of the scanning line with respect to the inspection object 3 by the control operation of the rotary polygon mirror 11 and the table feeder 12. is doing.

In FIG. 7B, a substrate on which a plurality of electronic components (shaded portions in FIG. 7B) are mounted is shown as the inspection object 3. As described above, the inspection range Zr in the height direction Z with respect to the inspection object 3 extends from a position higher than the top surface of the highest electronic component among the plurality of electronic components to a position that is the same as or lower than the substrate. It is preferable to set as follows. Therefore, in Fig. 7B, the point Px and the point Px ... Px are set higher than the electronic parts.

11 12 15

The point Px and the point Px ··· The point Px is set at a position lower than the board. In FIG. 7B, the black circle indicates the condensing point of the scanning light beam actually collected by the scanning condensing lens 2, and the dotted white circle indicates the scanning light beam before condensing by the scanning condensing lens 2. A virtual condensing point that is reflected by the surface of the inspection object 3 and is not actually condensed is shown.

[0055] The first mirror surface 11c force of the rotating polygon mirror 11 starts. In the first rotation, the irradiation light condensing point is the same position in the sub-scanning direction Y, from point Px to point Px, in the height direction position z force to z And 5 times

11 61 di dl d6 Changed and Z-scanned. Furthermore, when the rotating polygon mirror 11 rotates and the first mirror surface 11c starts to strike again, the sub-scanning direction position y changes by Yp in the direction opposite to the sub-scanning direction Y, and irradiation is performed.

di

The light condensing point changes from Px to Ρχ and Ζscans. In the same manner, the rotary polygon mirror 11

12 62

For each rotation, the sub-scanning direction position y changes at a constant interval Yp. In other words, the inspection object 3

di

On the other hand, Y-scanning is realized at a constant interval Yp for each rotation of the rotating polygonal mirror 11.

That is, in the appearance inspection apparatus and method of the first embodiment, during the rotational operation of the rotary polygonal mirror 11, the X-scan is performed with one mirror scan while the mirror surface angle λ is varied. Multiple mirror surfaces 1 lc are switched during one rotation of the rotating polygonal mirror 11 Ζ Scanning is performed. It can be performed.

Note that the spot diameter d of the light beam emitted from the light source 1 when it is irradiated onto the inspection object 3 varies depending on the inspection range Zr in the height direction Z of the inspection object 3. When the light intensity of the light flux emitted from the light source 1 has a Gaussian distribution (normal distribution) and the wavelength is λa, the inspection range Zr and the spot diameter d are approximately in the relationship of the following equations.

Zr = π / 4 ÷ la X d ²

For example, if the wavelength λ a is 600 nm, (d, Zr) = (30 / zm, 1.2 mm), (10 m, 131 m), (5 m, 32.7 m), (1 m, 1 Examples of setting the spot diameter d and the detection range Zr, such as 31 m). For example, when the inspection object 3 is a plurality of tar solders applied to the substrate, the inspection range Zr in the height direction Z is higher than the top surface of the highest cream solder among the plurality of cream solders. Therefore, it is preferable to set the position so as to extend over the same position as the substrate or lower than the substrate. In such cases, the thickness of the cream solder Since the maximum diameter is about 0.2 mm, the spot diameter d should be set to 15 μm and the inspection range Zr should be set to about 0.3 mm.

However, the above is only a theoretical value, and an optimal setting value may be set according to the intensity distribution of the light beam and the reflection state of the inspection object 3.

[0057] Next, the confocal optical system (reflecting lens 5 and shielding) is obtained by X scanning and Z scanning at the same sub-scanning direction position y of the inspection object 3 during one rotation of the rotary polygon mirror 11. The principle of the calculation method for obtaining the height information of the inspection object 3 from the photoelectric conversion signal output I obtained when the reflected light through the plate 6) enters the photodetector 7 will be described with reference to FIGS. 8A and 8B. .

FIG. 8A schematically shows the storage contents of the photoelectric conversion signal output I of the photodetector 7 in the data storage unit 13.

The data storage unit 13 is a sump dj so that the position X in the main scanning direction becomes a constant interval (= X resolution) during X scanning of the inspection object 3 by rotation of one mirror surface 1 lc of the rotating polygon mirror 11.

Only the m photoelectric conversion signal outputs I (i, j) of the photodetector 7 are stored under the control of the control unit 16 at the ring interval. Here, if j is a sampling number in the X direction (j = l to m, m is an integer), the position X in the main scanning direction is X 1, χ.

dj dl d2 dm

In addition, the data storage unit 13 performs the height direction position di of the irradiation light condensing point at the same sub-scanning direction position y of the inspection object 3 by one rotation of the rotary polygon mirror 11 having six mirror surfaces 11c.

Change z 5 times to store 6 X m photoelectric conversion signal outputs I (i, j) of the photodetector 7. Say di

In other words, since the mirror surface number i is 1 to 6, the inspection is performed up to the sub-scanning direction positions Y to Y. dl d6

Then, 6 pieces of 6 × mX photoelectric conversion signal outputs I (i, j) of the photodetector 7 are stored in the data storage unit 13.

In FIG. 8A, a line graph connecting photoelectric conversion outputs 1 (1, 1) to I (1, m) of the photodetector 7 with a short dotted line indicates the light intensity of the scanning light beam by the first mirror surface 11c. Show. A line graph connecting the photoelectric conversion outputs 1 (2, 1) to I (2, m) of the photodetector 7 with a long dotted line indicates the light intensity at the position X in the main scanning direction of the scanning light beam by the second mirror surface 11c. ing. light

2 dj

A line graph connecting the photoelectric conversion outputs 1 (6, 1) to I (6, m) of the detector 7 with solid lines indicates the light intensity at the position X in the main scanning direction of the scanning light beam by the sixth mirror surface 11c.

6 dj

[0060] FIG. 8B shows the rotation polygon mirror 11 stored in the data storage unit 13 in the calculation unit 14. This figure schematically shows a processing method for obtaining the dj measurement height Z at each position X in the main scanning direction from 6 X m photoelectric conversion signal outputs I (i, for rotation).

mj

Six photoelectric conversion signal outputs 1 (1, 1) to 1 (6 dl) of photodetector 7 at main scanning direction position X

, 1), the main scanning direction position X and the sub-scanning direction position y of the inspection object 3 are the same.

Since the photoelectric conversion signal output I is z-scanned at the dj di point, the principle of the confocal method is used.

As shown by the long dotted line of 8B, dl at the height Z1 of the inspection object 3 at the position X in the main scanning direction

The closest irradiated light focus point at the height position z

d2 Photoelectric conversion signal output I is the maximum curve. The extraction unit 14a of the calculation unit 14 determines the maximum height direction position z as the measurement height d2

Extract as Z.

ml

[0061] Further, photoelectric conversion signal outputs 1 (1, 2) to 1 (4 d2) of the photodetector 7 at the position X in the main scanning direction.

, 2), the main scanning direction position X and the sub-scanning direction position y of the inspection object 3 are the same.

As shown by the short dotted line in 8B, the height Z2 of the inspection object 3 at the position X in the main scanning direction is d2

The closest irradiated light focus point at the height position z

dl A curve with maximum photoelectric conversion signal output I. The extraction unit 14a of the calculation unit 14 converts the maximum height direction position z into the measurement height dl.

Extract as Z.

In addition, photoelectric conversion signal output 1 (2, 3) to 1 (6 d3

, 3), the main scanning direction position X and the sub-scanning direction position y of the inspection object 3 are the same.

As indicated by the solid line in Fig. 8B, the height of the inspection object 3 at the position X in the main scanning direction X

D4 in the curve where the photoelectric conversion signal output I becomes the maximum at the position z in the height direction of the near-focus point of the irradiated light

Become. The extraction unit 14a of the calculation unit 14 extracts the maximum height direction position z as the measurement height z and d4 m3.

In the same manner, by extracting each measurement height 測定 at each main scanning direction position X, dj mj

The height information on the scanning line of the inspection object 3 can be obtained.

Next, the calculation method for obtaining the height information of the inspection object 3 will be described in more detail with reference to FIGS. 2 and 8C to 8E. Here, the electronic component mounted on the board 3A as shown in FIG. Figure 8C shows an example of an XZ scan for inspection object 3. FIG. 8D is a schematic diagram illustrating an example of the contents stored in the data storage unit 13, and FIG. 8E is a diagram illustrating an example of the calculation method of the appearance position coordinate calculation unit 14b.

In FIG. 8C, a black circle indicates a condensing point of the scanning light beam actually condensed by the scanning condensing lens 2, and a dotted white circle indicates a point before condensing by the scanning condensing lens 2. The scanning light beam is reflected on the surface of the inspection object 3 and shows a virtual condensing point that is not actually condensed. That is, in FIG. 8C, the scanning light beam is in the height direction position z, the main scanning direction position X d4 d and X, the height direction position Z, the main scanning direction position X and X, and the height direction.

2 d3 d2 d2 d3

At position z and main scanning direction position x to χ, it is detected before being condensed by the scanning condenser lens 2 d6 dl dm

反射 Reflected on the surface of the object 3.

In FIG. 8C, the X scan at the height position z is the first mirror surface dl of the rotating polygon mirror 2.

X scanning at the height direction position z is performed by the second mirror surface 11c,

1 d2 2

Similarly, the X scan at the height direction position z˜ is performed from the second mirror surface 11c to the sixth mirror surface 11c by d3 d6 2 6.

[0064] The light intensity of the epi-reflected light received by the photodetector 7 increases as the scanning light beam collected by the scanning condenser lens 2 is reflected by the inspection object 3 near the focal point. Become. In other words, in FIG. 8C, when the received light intensity is 1, the incident light reflected by the light detector 7 has the strongest incident light intensity farther from the received light intensity 1, that is, the received light intensity 2, the received light intensity 3 The light intensity of the epi-reflected light received by the photodetector 7 becomes weaker as

Therefore, for example, at the position X in the main scanning direction and at the position z in the height direction, the received light intensity d3 dl

The light is condensed at 3 and is collected at the received light intensity 2 at the height direction position z, and is collected at the received light d2 d3 light intensity 1 at the height direction position z to form a condensing point of the scanning light beam. However, at height position _Z d4, light is collected with received light intensity 1 and at height position _Z it is _collected with received light intensity 2 and height direction d5

At position _Z , it should be focused with a received light intensity of 3, but actually it scans the surface of inspection object 3 d6

Since each light beam is reflected, it becomes a condensing point of a virtual scanning light beam.

FIG. 8D is a graph showing the relationship between the photoelectric conversion signal output I obtained by photoelectric conversion of the received light intensities 1 to 5 shown in FIG. 8C by the photodetector 7 and the position X in the main scanning direction. In Figure 8D, the light dj

A long dotted line connecting the photoelectric conversion signal outputs 1 (1, 1) to I (1, m) of the detector 7 indicates the light intensity at the position X in the main scanning direction of the scanning light beam by the first mirror surface 11c. Also the photodetector The short dotted line connecting the photoelectric conversion signal outputs I (2, 1) to I (2, m) of 7 is due to the second mirror surface 11c.

2 The light intensity at the position X in the main scanning direction of the scanning beam is shown. Light dj with light detector 7

The alternate long and short dash line connecting the electrical conversion signal outputs 1 (3, 1) to I (3, m) is the scanning light from the third mirror surface 11c.

Three

The light intensity at the position X in the main scanning direction of the bundle is shown. In addition, photoelectric conversion dj of photodetector 7

The two-dot chain line connecting signal outputs 1 (4, 1) to 1 (4, m) is the main scanning beam of the fourth mirror surface 11c.

Four

The light intensity at the scanning position X is shown. In addition, the photoelectric conversion signal output dj of the photodetector 7

The straight line connecting forces 1 (5, 1) to I (5, m) is the position in the main scanning direction of the scanning beam by the fifth mirror surface 11c.

Five

The light intensity at device X is shown. The photoelectric conversion signal output 1 (6, 1) to dj of the photodetector 7

1 The thick straight line connecting (6, m) is at the position X in the main scanning direction of the scanning beam by the sixth mirror surface 11c.

It shows the light intensity at 6 dj.

FIG. 8E shows the photoelectric conversion signal output dj di at each height direction position z for each main scanning direction position X.

This is a graph with force I marked and connected with a smooth curve. Main scan direction position

Photoelectric conversion at each height position z (scanning of the first mirror surface 11c force and the sixth mirror surface 11c) at X dl di 1 6

Signal outputs 1 (1, 1) to I (6, 1) are indicated by triangular marks in FIG. 8E. Similarly, photoelectric conversion signal output 1 (2, 1) to d2 di at each height direction position z at main scan direction position X

(2, 6) is indicated by a square mark in Fig. 8E, and each height d3 at the position X in the main scanning direction

The photoelectric conversion signal outputs 1 (3, 1) to (3, 6) at the direction position z are indicated by circular marks in FIG.

Show.

[0067] As shown in FIG. 8E, at the main scanning direction position X (triangle), the photoelectric conversion signal output I is dl

The maximum value is between the height direction position z and the height direction position _Z. Operation unit 14 extraction unit 14a d5 d6

Indicates the height between the height direction position z and the height direction position z as the main scanning direction d5 d6 of the inspection object 3.

Extracted as measured height Z at position X. Also, main scanning direction position X (square) or dl ml d2

Is the main scanning direction position χ

When d3 (circular), the photoelectric conversion signal output I is

The maximum value is between d3 and the height direction position z. The extraction unit 14a of the calculation unit 14 measures the height between the height direction position z and the d4 d3 height direction position z at the measurement height d4 d2 d3 at the position X or X of the inspection object 3 in the main scanning direction. Extract by z or _Z. In the same manner, each main scan m2 ml 3

By extracting the measurement height position z at the direction position χ, the scanning line dj mj of the inspection object 3 is extracted.

Upper height information can be obtained. [0068] It should be noted that the height direction position z varies discretely at an interval fxda X tan (| 8) as described above.

di

Thus, when the extraction unit 14a extracts the height direction position z that becomes the maximum value as described above, the measurement height

di

The interval of the length z is also a discrete value of fXdaXtan (| 8) (that is, the measurement height resolution ability ¾XdaXtaη (ι8)). However, by performing arithmetic processing such as polynomial interpolation in the appearance position coordinate calculation unit 14a, the intermediate point between each height direction position z can be obtained as the measurement height z.

di mi

The resolution can be reduced.

In addition, in order to perform such arithmetic processing, it is necessary to associate the photoelectric conversion signal output I of the photodetector 7 stored in the data storage unit 13 with the mirror surface number i of the rotary polygon mirror 11. For this purpose, the control unit 16 outputs a signal (hereinafter referred to as a rotation synchronization signal) that synchronizes with the rotation of the rotary polygon mirror 11 to the appearance position coordinate calculation unit 14b once per rotation. Further, the control unit 16 causes the appearance position coordinate calculation unit 14b to output a signal (hereinafter referred to as a scanning synchronization signal) that synchronizes with the scanning operation by each mirror surface 11c once for each mirror surface scanning. Then, the appearance position coordinate calculation unit 14b combines the rotation synchronization signal and the scanning synchronization signal to associate the photoelectric conversion signal output I of the photodetector 7 with the mirror surface number i of the rotary polygon mirror 11. Is possible.

As described above, according to the appearance inspection apparatus and method of the first embodiment, the data of the photoelectric conversion signal output I of the photodetector 7 in one rotation of the rotary polygon mirror 11 is stored in the data storage unit 13. Of the data stored in the data storage unit 13 from the calculation unit 14, the position X in the main scanning direction

dj and sub-scanning direction position y

By obtaining the height direction position z at which the photoelectric conversion signal output I becomes the maximum at the same point as di, height information on the scanning line of the inspection object 3 (that is, the XZ cross section di

Shape).

Furthermore, according to the appearance inspection apparatus and method of the first embodiment, as shown in FIG. 7B, the control unit 16 converts the feed amount Yt of the table feeder 12 into the rotation of the rotary polygon mirror 11 at the equal angular velocity. By synchronizing and controlling the multiple irradiation light condensing points by each mirror surface in the height direction Z of the inspection object 3, each main scanning direction in the XY scanning range of the inspection object 3 Information on the height direction position z at position X and each sub-scanning direction position y (that is,

dj di mi

, Position coordinates).

Note that, according to the appearance apparatus and method of the first embodiment, the calculation unit 14 performs inspection pairing. For example, in Fig. 7B and Fig. 8A, the position coordinates of the appearance of figurine 3 are m points in the main scanning direction (the number of samplings in the main scanning direction X) and 5 points in the sub-scanning direction (the number of rotations of the rotating polygon mirror 11). ) And the total of 6 points in the height direction (number of mirrors of the rotating polygon mirror) (m X 5 X 6 =) 30 X m points, so that the appearance of the inspection object can be inspected in three dimensions. Can do.

As described above, in the first embodiment, the method of moving the inspection object 3 in the sub-scanning direction Y by the table feeder 12 has been described. However, the inspection object 3 is fixed and the entire optical system is sub-running. The same effect can be obtained by moving in the heel direction Y. In the first embodiment, the scanning condensing lens 2 has been described as an f0 lens. However, when the relationship between the main scanning direction position X and the incident angle Θ is not linearly proportional (for example, X = f X sin (Θ) or X = f X tan (Θ) dd

Etc.), the same effect can be obtained.

[0072] Second Embodiment

FIG. 9A is a schematic view of the configuration of the optical system of the appearance inspection apparatus and method according to the second embodiment of the present invention viewed from the sub-scanning direction Y. FIG. 9B is a schematic view of the configuration of the optical system of the appearance inspection apparatus according to the second embodiment of the present invention viewed from the main scanning direction X.

As shown in FIGS. 9A and 9B, the visual inspection apparatus and method according to the second embodiment of the present invention is a plane in which the optical axis of the scanning condenser lens 2 is orthogonal to the rotational axis 1 lb of the rotary polygon mirror 11. Force angle β, with a scanning condensing lens 2Α arranged in parallel to the height direction 傾斜 without tilting, and forming a condensing point position between the scanning condensing lens 2Α and the inspection object 3 This is different from the appearance inspection apparatus of the first embodiment of the present invention in that it further includes a wedge-shaped long prism 15 having an entrance surface and an exit surface that are parallel to the main scanning direction X, which constitutes an example of the optical system for use. Since the other points are the same as those of the visual inspection apparatus and method according to the first embodiment of the present invention, the overlapping description is omitted.

[0074] As shown in Figs. 9 and 9B, since the incident surface 17a and the exit surface 17b of the long prism 17 are arranged in parallel to the main traveling direction X, the scanning light beam passes through the long prism 17. Passes and does not bend in the plane perpendicular to the sub-scanning direction Y, but bends at an angle γ only in the plane perpendicular to the main scanning direction X due to the action of refraction, and is collected at the irradiation light condensing point Pb. Then, the scanning light beam condensed at the condensing point P b linearly scans the inspection object 3 in the main scanning direction X by the rotation of the rotary polygon mirror 11. When the mirror angle of the rotating polygonal mirror 11 is λ = «Ζ2, As in the first embodiment, the scanning light beam emitted from the sensor 2 is a distance y in the sub-scanning direction Y.

in

= f X Translated by α and enters the long prism 17. The scanning beam incident on the long prism 17 has its parallel movement changed from the distance y to the distance y by the action of the long prism 17.

md, and the irradiation light condensing point Pb-1 is shifted by a distance y with respect to the sub-scanning direction Y with respect to the irradiation light condensing point Pb when the position of the light condensing point Pb-1 passes through the center of the optical axis of the scanning condensing lens 2. Distance z in direction Z

d d Get lost.

The difference of the second embodiment from the first embodiment is that the long prism 17 is newly provided and the point that the inclination β of the scanning condenser lens 2 is eliminated. In both the first and second embodiments, the mirror surface angle of the rotating polygonal mirror 11 allows the X-scanning and the saddle scanning to be performed simultaneously on the inspection object 3, and the same effect can be exhibited.

Next, the operation of the long prism 17 will be described in detail with reference to FIGS. 10A and 10B. FIG. 10A is a diagram for explaining the action of the long prism 17, and FIG. 10B is a diagram for explaining the movement of the irradiation light condensing point by the long prism 17.

As shown in Figure 10A, the apex angle of the long prism 17 is a, the refractive index is n, and the light beam of the light source 1 is incident from the point A2 on the incident surface 17a of the long prism 17, and the point on the exit surface 17b. When emitted from C2, due to snell's law and geometrical relationship, the angle at which the scanning beam emitted from the scanning condenser lens 2 is bent by the long prism 17 (hereinafter referred to as the bending angle) γ is as follows: become. Here, the angle (hereinafter referred to as the incident angle) formed by the scanning light beam (hereinafter referred to as incident light and! ヽぅ) emitted from the scanning condenser lens 2 and incident on the long prism 17 with respect to the incident surface 17a is defined as bl1. In addition, the angle formed by the scanning light beam entering the long prism 17 with the incident surface 17a is bl2, and the angle with the exit surface 17b is b21. Further, the angle formed by the scanning light beam (hereinafter referred to as “emitted light”) emitted from the long prism 17 and the exit surface 17b is defined as b22.

[0077] sin (bl2) = sin (bl l) / n (snell's law at point A2)

sin (b22) = sin (b21) X n (snell's law at point C2)

a = b21 + bl2 (triangular geometric relationship)

γ = (bl l -bl2)-(b21 -b22) (geometric relationship)

= bl l + b22-a = fl (a, n, bl l)

In other words, the bending angle γ is a function fl (a, n, bl l) of the apex angle a, the refractive index η, and the incident angle bl l. It becomes. Therefore, the scanning light beam that passes through points A1 to C1 translated in the sub-scanning direction Y by the distance y is also the same incident angle bll as the scanning light beam that passes through points A2 to C2, and the bending angle is γ. . In other words, the light emitted from point C1 through point A1 to point C1 is parallel to the light emitted from point C2 through point C2 and emitted from point C2.

[0078] The distance y between the emitted light emitted from the point C1 and the emitted light emitted from the point C2 is the point A1.

d

The distance y between the incident light and the incident light incident on point A2 is linearly proportional, and the ratio

m

The example coefficient is Snell's law force as shown in the following equation, and eventually becomes a function f2 (a, n, bll) of the apex angle a'refractive index n'incident angle bll.

[0079] y / γ = cos (b 12) / cos (b 11) X cos (b22) / cos (b21) = f 2 (a, n, bll)

d in n

By this action, as shown in FIG. 9B, the irradiation light condensing point Pb moves to the irradiation light condensing point Pb-1 by moving the distance y in the traveling direction of the scanning light beam.

d

[0080] Next, the movement of the irradiation light condensing point Pb in the height direction Z by the long prism 17 will be described. As shown in Fig. 10B, when a stray beam with a small focusing angle Θ is incident on a long prism 17 having a thickness f of refractive index n, the collected light is collected by Snell's law and paraxial approximation (sin (θ) ^ Θ). The light spot moves from point D to point に by dz = tX (l-1 / n) in the direction of travel of the scanning beam. For this reason, in FIG. 10A, the incident light incident on point A1 is incident on the point A1 if the incident light is focused at point B1 at a distance of L1 from point A1 unless it passes through the long prism 17. ~ The irradiation light condensing point E1 of the emitted light that passes through the point C1 and is emitted from the point C1 is a point D1 (distance from the point A1 along the path of the scanning light beam bent by the long prism 17 (distance). For A1B1 = distance A1C1 + distance C1D1 = L1), the distance dz = tX (1-lZn) moves in the traveling direction of the scanning light flux (t = distance A1C1).

[0081] Similarly, the irradiation light condensing point of the incident light incident on the point A2 is the distance = t X (l-1 / n)

Move 2 2 n to point E2. In other words, the incident position with respect to the incident surface 17a of the long prism 17 is different even if the scanning light beam has the same distance to the irradiation light condensing point if it does not pass through the long prism 17 (for example, point A1 and point A2). ) And the position of the irradiation light condensing point in the traveling direction of the scanning light beam are different by z = (t−t) X (1-1 / n). Here, it passes through the long prism 17

d 2 1 n

The difference in distance between the points A1 and A2 is apparent from the geometric relationship of the triangle

twenty one

The proportionality coefficient is a function of the apex angle a and the incident angle bl2. Furthermore, cl2 = y Since Zcos (bl l) has a relation, after all, z is linearly proportional to the distance y, and the proportionality coefficient is ndm

It is a function f3 of the angle a, the refractive index n and the incident angle bl l.

,

[0082] z / y = f3 (a ゝ n, bl l)

d in n

9B, the scanning light beam is bent by an angle γ by the action of the long prism 17, and from the irradiation light condensing point Pb to the point Pb-1 ′ (to the sub scanning direction Υ). The distance y and the distance z in the height direction Z) move, and the straight line connecting point Pb and point Pb-1 is the dd of the scanning beam

Inclined by an angle β of the following equation with respect to a plane perpendicular to the traveling direction.

[0083] tan (j8) = z / y = f3 (a, n, bl l) / f2 (a ゝ n, bl l)

d d n n

In other words, by changing the three parameters of the long prism 17 (vertical angle a, refractive index n _n , and incident angle bl l), the height direction position z and the sub-scanning direction position y with respect to the inspection object 3 are changed.

Di di can be designed, and a design with a high degree of freedom becomes possible.

[0084] It should be noted that, by appropriately combining any of the various embodiments, the effects possessed by them can be produced.

[0085] Although the present invention has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included therein, so long as they do not depart from the scope of the present invention according to the appended claims.

[0086] Specification of Japanese Patent Application No. 2005—116869 filed on April 14, 2005

The disclosures of the drawings, the drawings, and the claims are hereby incorporated by reference in their entirety.

Industrial applicability

[0087] The appearance inspection apparatus and method according to the present invention has an effect that the appearance coordinates of the inspection object can be obtained at high speed and with high accuracy by adding a simple function to the linear scanning optical system using the rotary polygon mirror. In particular, it is useful as an appearance inspection apparatus for an object spreading on a plane, and specifically, an appearance inspection apparatus and method for inspecting the mounting state of electronic components and the application state of cream solder in a soldering process of a mounting board Useful for.

Claims

The scope of the claims

A light source that emits a luminous flux;

By rotating the rotating polygon mirror, the light beam deflected and scanned by the respective mirror surfaces of the rotating polygon mirror is condensed at the condensing point, and the condensing point is orthogonal to the main scanning direction of the inspection object. A condensing point position forming optical system that moves the inspection range in the height direction and the condensing point position forming optical system that is reflected by the inspection object after passing through the condensing point position forming optical system The light intensity of the reflected light deflected by the mirror surface of the rotary polygon mirror, and the light intensity depending on the distance between the condensing point and the reflection point of the light beam on the inspection object, A photodetector that performs photoelectric conversion to a photoelectric conversion signal output; and in synchronization with the rotation of the equiangular velocity of the rotary polygon mirror, the inspection object is placed in a sub-scanning direction orthogonal to the main traveling direction and the height direction. An inspection object moving device to be moved; and

The inspection object moving device is moved in the inspection range in the height direction by the focusing point position forming optical system while the rotary polygon mirror makes one rotation at the equiangular velocity, and the And moving the inspection object in the sub-scanning direction so that the condensing point shifted in the sub-scanning direction by the mirror surface is linearly scanned in the height direction of the inspection object The rotating polygon mirror opens one more revolution at the equiangular speed. Before starting, the inspection object is moved in the sub-scanning direction, and an external inspection is performed by linear scanning in the main scanning direction and movement of the condensing point in the inspection range in the height direction. An appearance inspection apparatus configured to perform an appearance inspection at one rotation of the rotary polygon mirror and a different part on the inspection object.

[2] The condensing point position forming optical system is arranged such that an optical axis is inclined with respect to a direction orthogonal to the rotation axis of the rotary polygon mirror, and the respective mirror surfaces of the rotary polygon mirror are used. A scanning condensing lens that condenses the deflected beam at the condensing point is provided, and the condensing point moves in the inspection range in the height direction while moving linearly in the main scanning direction. The appearance inspection apparatus according to claim 1, wherein:

[3] The condensing point position forming optical system comprises:

Scanning, in which an optical axis is arranged in parallel with a direction orthogonal to the rotation axis of the rotary polygon mirror, and the light flux deflected and scanned by the respective mirror surfaces of the rotary polygon mirror is condensed at the condensing point A condenser lens;

The light beam that has passed through the scanning condensing lens is incident from the incident surface of the prism, bent and emitted from the exit surface, and the condensing point moves linearly in the main scanning direction. The appearance inspection apparatus according to claim 1, wherein the inspection range in the height direction is moved.

[4] In addition, a data storage unit that stores the photoelectric conversion signal output of the reflected light output from the photodetector during at least one rotation of the rotary polygon mirror,

The arithmetic unit obtains a position coordinate of an appearance of the inspection object by obtaining a position in the height direction of the inspection object based on the photoelectric conversion signal output stored in the data storage unit, and the inspection The appearance inspection apparatus according to claim 1, wherein the appearance inspection of an object is performed.

[5] A rotating polygon mirror having at least three mirror surfaces on the outer periphery and having a mirror surface angle that is an angle formed between the rotation shaft and the mirror surface is different for each mirror surface. The light beam emitted from the light source to the mirror surface is linearly scanned in the main scanning direction while deflecting the light beam toward the inspection object. By the system, the light beam deflected and scanned by the respective mirror surfaces of the rotating polygon mirror is condensed at the condensing point, and the condensing point is inspected in the height direction perpendicular to the main scanning direction of the inspection object. The condensing point shifted in the sub-scanning direction orthogonal to the main scanning direction and the height direction by the respective mirror surfaces having different mirror surface angles is moved in a range, and the height of the inspection object is The inspection object is moved in the sub-scanning direction so as to be scanned linearly in the direction, and reflected by the inspection object moving in the sub-scanning direction, the condensing point position forming optical system is Via the rotation many The light intensity of the reflected light deflected to the mirror surface of the mirror, which depends on the distance between the condensing point and the reflection point of the inspection object of the light beam, is photoelectrically converted into a photoelectric conversion signal output. Based on the photoelectric conversion signal output, the position coordinates of the appearance of the inspection object are obtained, the appearance of the inspection object is inspected,

Next, before the rotating polygon mirror starts another rotation at the equiangular speed, the inspection object is moved in the sub-scanning direction,

Next, an appearance inspection by the linear scan in the main scanning direction and a movement of the condensing point in the inspection range in the height direction, an appearance inspection in the one rotation of the rotary polygon mirror and the inspection object An appearance inspection method characterized in that it is performed in different parts above.

[6] In the deflection scanning, scanning condensing that constitutes the condensing point position forming optical system and is arranged so that an optical axis is inclined with respect to a direction orthogonal to the rotational axis of the rotary polygon mirror. While the light bundle deflected and scanned by the respective mirror surfaces of the rotary polygon mirror is condensed by the lens onto the condensing point, the condensing point moves linearly in the main scanning direction and the height is increased. 6. The appearance inspection method according to claim 5, wherein the light is condensed so as to move in the inspection range in the direction.

[7] In the deflection scanning, a scanning condensing lens that constitutes the condensing point position forming optical system and is arranged so that an optical axis is parallel to a direction orthogonal to the rotational axis of the rotary polygon mirror. Thus, the light beam deflected and scanned by the respective mirror surfaces of the rotary polygon mirror is condensed at the condensing point, A prism that constitutes the condensing point position forming optical system and is arranged between the scanning condensing lens and the inspection object so that an incident surface and an exit surface are parallel to the main scanning direction. The light beam that has passed through the scanning condensing lens enters from the incident surface of the prism, is refracted and exits from the exit surface, and the condensing point moves linearly in the main scanning direction. 6. The appearance inspection method according to claim 5, wherein the light is condensed so as to move within the inspection range in the height direction.