Focus control device for optical inspection device

Abstract

To provide a focus control device for an optical inspection device which enables control of the separation distance with respect to an inspection object.SOLUTION: A focus control device for an optical inspection device includes: a first irradiation part that emits first light toward an interior of a lens barrel part of the optical inspection device, and that is provided at an upper portion thereof with an inspection image sensor of the optical inspection device and accommodates, at an inner lower portion thereof, a lens part; a 1-1 reflection part for reflecting the first light; the lens part that causes secondary refraction of the first light reflected by an inspection object; a 1-2 reflection part for reflecting the secondarily refracted first light; a second irradiation part that emits second light into the lens barrel part from the opposite side; and a 2-1 reflection part for reflecting the second light. The lens part secondarily refracts the second light reflected by the inspection object toward a 2-2 reflection part. The focus control device further includes the 2-2 reflection part that reflects the secondarily refracted second light. The focus control device controls a separation distance between the lens part and the inspection object on the basis of first and second light position data being positions of the first and second lights sensed by a focus control image sensor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a focus control device for an optical inspection device, and more specifically, to a focus control device for an optical inspection device in which first and second lights irradiated from a first irradiation unit and a second irradiation unit of the optical inspection device are reflected along a path parallel to the direction of movement of the lens unit, and passed through the lens unit, and after passing through the lens unit and being refracted, the first and second lights reflected from the object to be inspected are refracted again by the lens unit and reflected toward a focus control image sensor via a second reflection unit, thereby sensing the respective positions of the first and second lights on the focus control image sensor, and controlling the separation distance from the object to be inspected based on the respective positions of the first and second lights. [Background technology]

[0002] Machine vision is a technology that gives machines the visual and judgment capabilities that humans possess, and in which a hardware and software system processes the functions of human perception and judgment on their behalf.

[0003] As various industrial fields have recently been shifting to automation, machine vision has been widely used in almost every industry, including semiconductors, aluminum, automobiles, mobile phones, logistics, pharmaceuticals, medical care, food and beverages, consumer goods, wood, textiles, glass, iron, casting, and chemicals, for not only simple measurements but also for processing and evaluating acquired images, depending on the user's purpose.

[0004] In particular, machine vision is applied to inspection equipment that detects defects in semiconductor substrates and components. In semiconductor or LCD manufacturing sites, the final product is completed through many separate processes. Therefore, defects in components such as semiconductor substrates during the production process can cause serious problems, requiring the finished product to be scrapped later. To solve this problem, inspection equipment is used to detect defects in semiconductor substrates and components at the appropriate time.

[0005] Generally, high-resolution digital cameras or line scan cameras that operate on a scanner-like principle are used to inspect semiconductors, etc. Line scan cameras are particularly popular because they are advantageous for capturing ultra-high resolution images.

[0006] However, when using a digital camera or line scan camera, the image captured may be in focus or out of focus depending on the distance between the camera (specifically the lens) and the subject, which can cause the inspection results to differ. Therefore, the most appropriate camera distance must be determined in advance through testing depending on the inspection subject.

[0007] However, conventional inspection equipment requires the tester to manually adjust the camera distance (i.e., focus) even when changing the camera distance, which is tedious. This manual adjustment method requires a lot of time and effort, and it is difficult to ensure consistency in test results. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Registration No. 10-0939541 Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide a focus control device for an optical inspection device in which the first light and the second light irradiated from the first irradiation unit and the second irradiation unit of the optical inspection device are reflected along a path parallel to the direction of movement of the lens unit and passed through the lens unit, and after passing through the lens unit and being refracted, the first light and the second light reflected from the object to be inspected are refracted again by the lens unit and reflected towards the focus control image sensor via the second reflection unit, thereby sensing the respective positions of the first light and the second light on the focus control image sensor and controlling the separation distance from the object to be inspected based on the respective positions of the first light and the second light.

[0010] The objects of the present invention are not limited to the above objects, and other objects and advantages of the present invention not mentioned above can be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it is easily understood that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0011] The focus control device for an optical inspection device according to the present invention includes a first irradiation unit that irradiates a first light from one side of a barrel unit of the optical inspection device, the barrel unit having an inspection image sensor for the optical inspection device attached to an upper part thereof and a lens unit housed in an inner lower part thereof, toward the inside of the barrel unit; a 1-1 reflection unit that reflects the first light irradiated by the first irradiation unit toward the lens unit; the lens unit that primarily refracts the first light reflected by the 1-1 reflection unit toward the inspection object and secondarily refracts the first light reflected by the inspection object toward a 1-2 reflection unit; the 1-2 reflection unit that reflects the first light secondarily refracted by the lens unit toward a focus control image sensor; and a 1-3 reflection unit that irradiates a second light from the other side of the barrel unit toward the inside of the barrel unit. and a 2-1 reflecting unit that reflects the second light irradiated by the second irradiating unit toward the lens unit, wherein the lens unit primarily refracts the second light reflected by the 2-1 reflecting unit toward the object to be inspected and secondarily refracts the second light reflected by the object to be inspected toward the 2-2 reflecting unit, and the focus control device of the optical inspection device may include a 2-2 reflecting unit that reflects the second light secondarily refracted by the lens unit toward the focus control image sensor, and a control unit that controls a separation distance between the lens unit and the object to be inspected based on first light position data that is the position of the first light sensed by the focus control image sensor and second light position data that is the position of the second light sensed by the focus control image sensor.

[0012] The 1-1 reflecting unit reflects the first light irradiated by the first irradiating unit along a 1-1 reflection path toward the lens unit, and the lens unit can secondarily refract the first light reflected by the object to be inspected along a 1-2 refraction path toward the 1-2 reflecting unit.

[0013] The first-first reflection path may be parallel to a moving direction in which a lens unit moves to control the focus.

[0014] The angle formed by the first-second bent path with respect to the moving direction is included in a first angle range.

[0015] The 2-1 reflecting unit reflects the second light irradiated by the second irradiating unit along a 2-1 reflection path toward the lens unit, and the lens unit can secondarily refract the second light reflected by the object to be inspected along a 2-2 refraction path toward the 2-2 reflecting unit.

[0016] The 2-1 reflection path may be parallel to a moving direction in which the lens unit moves to control the focus.

[0017] The angle formed by the 2-2 bent path with respect to the moving direction is included in a second angle range.

[0018] The control unit can control the distance between the lens unit and the object to be inspected so that the position of the first light is located within a first reference area and the position of the second light is located within a second reference area. [Effects of the Invention]

[0019] According to the present invention, the first light and the second light irradiated from the first irradiation unit and the second irradiation unit of the optical inspection device are reflected along a path parallel to the direction of movement of the lens unit and passed through the lens unit. After passing through the lens unit and being refracted, the first light and the second light are reflected from the object to be inspected and are again refracted by the lens unit and reflected toward the focus control image sensor via the second reflection unit. As a result, the positions of the first light and the second light on the focus control image sensor are sensed, and the distance between the object to be inspected and the object to be inspected can be controlled based on the positions of the first light and the second light. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a focus control device of an optical inspection apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of a focus control device of an optical inspection apparatus according to an embodiment of the present invention. [Figure 3] 3 is an example showing the inside of a focus control device of an optical inspection device and a travel path of light according to an embodiment of the present invention. [Figure 4] 4 is a diagram showing an example of light sensed by a focus control image sensor in FIG. 3. FIG. [Figure 5] 10 is another example showing the inside of the focus control device of the optical inspection device and the travel path of light according to one embodiment of the present invention. [Figure 6] 6 is a diagram showing an example of light sensed by the focus control image sensor in FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Various embodiments of the present invention will be described below with reference to the accompanying drawings. However, this is not intended to limit the present invention to the specific embodiments, and should be understood to include various modifications, equivalents, and / or alternatives of the embodiments of the present invention. In describing the drawings, like reference numerals may be used to refer to like components.

[0022] As used herein, terms such as "have," "can have," "include," or "can include" refer to the presence of a relevant feature (e.g., a value, function, operation, or component such as a part) and do not exclude the presence of additional features.

[0023] As used herein, phrases such as "A or B," "at least one of A and / or B," or "one or more of A and / or B" may include all possible combinations of the items listed together. For example, "A or B," "at least one of A and B," or "at least one of A or B" may refer to all of the following: (1) at least one A, (2) at least one B, or (3) at least one A and at least one B.

[0024] As used herein, terms such as "first," "second," "first," or "second" may modify various components regardless of order and / or importance, and are used only to distinguish one component from another, not to limit the corresponding component. For example, a first user device and a second user device may represent different user devices regardless of order or importance. For example, a first component may be named a second component, and similarly, the second component may be named interchangeably with the first component, without departing from the scope of the invention as set forth herein.

[0025] When a component (e.g., a first component) is referred to as being "operatively or communicatively coupled with" or "connected to" another component (e.g., a second component), it should be understood that the component may be directly connected to the other component or may be connected through another component (e.g., a third component). Conversely, when a component (e.g., a first component) is referred to as being "directly coupled with" or "directly connected to" another component (e.g., a second component), it should be understood that there is no other component (e.g., a third component) between the component and the other component.

[0026] As used herein, the phrase "configured to" can be used interchangeably with, for example, "suitable for," "having the capacity to," "designed to," "adapted to," "made to," or "capable of," depending on the context. The term "configured to" does not necessarily refer only to hardware that is "specifically designed to." Instead, in some contexts, the phrase "device configured to" can mean that the device is "capable of" working with other devices or components.

[0027] The terms used in this specification are merely used to describe particular embodiments and may not be intended to limit the scope of other embodiments. A singular expression may include a plural expression unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person of ordinary skill in the art described herein. Among the terms used herein, terms generally defined in dictionaries may be interpreted as meanings that are the same as or similar to the meanings they have in the context of the relevant art, and unless explicitly defined herein, they should not be interpreted in an ideal or overly formal sense. In some cases, even terms defined herein cannot be interpreted to exclude embodiments of this specification.

[0028] Figure 1 is an oblique view of a focus control device of an optical inspection device according to one embodiment of the present invention, Figure 2 is a front view of a focus control device of an optical inspection device according to one embodiment of the present invention, Figure 3 is an example showing the inside of the focus control device of an optical inspection device according to one embodiment of the present invention and the path of light movement, and Figure 4 is a diagram showing an example of light sensed by the focus control image sensor in Figure 3.

[0029] 1 to 4, a focus control device 100 for an optical inspection device according to one embodiment of the present invention is attached to the optical inspection device and is capable of controlling the focus of the optical inspection device.

[0030] Such an optical inspection device can be a device that photographs the inspection object 3 and judges whether or not the inspection object 3 has a defect.

[0031] For this purpose, the optical inspection device can include a cylindrical lens barrel portion 2 and an inspection image sensor 1 attached to the top of the lens barrel portion 2.

[0032] Meanwhile, inside the lens barrel part 2, a lens part 130 of a focus control device 100 of an optical inspection apparatus according to an embodiment of the present invention may be located.

[0033] Specifically, the lens unit 130 may be located at the lower inner portion of the lens barrel unit 2 .

[0034] At this time, the lens barrel 2 is provided with a motor, an actuator, etc., and can move the lens unit 130 located at the bottom in the vertical direction.

[0035] The inspection object 3 may be transferred to a position below the lens unit 130 by the transfer device 4, and then transferred to another area after the inspection is completed. Such a transfer device 4 may be a conveyor device.

[0036] The focus control device 100 of an optical inspection device according to one embodiment of the present invention can adjust the focus of the optical inspection device so that the image of the object to be inspected 3 generated by the inspection image sensor 1 becomes clear.

[0037] Specifically, the focus control device 100 of the optical inspection device according to one embodiment of the present invention can adjust the focus of the optical inspection device by controlling the distance between the lens unit 130 and the object 3 to be inspected.

[0038] More specifically, the focus control device 100 of the optical inspection device according to one embodiment of the present invention can adjust the focus of the optical inspection device by outputting a control signal to the lens barrel section 2 to move the lens section 130 in the vertical direction, thereby controlling the distance between the lens section 130 and the object to be inspected 3.

[0039] To this end, the focus control device 100 of the optical inspection device according to one embodiment of the present invention may include a first irradiation unit 110a, a first-1 reflection unit 120a, a lens unit 130, a first-2 reflection unit 140a, a focus control image sensor 150, a second irradiation unit 110b, a second-1 reflection unit 120b, a lens unit 130, a second-2 reflection unit 140b, and a control unit 160.

[0040] The first irradiating section 110a can irradiate the first light from one side of the barrel section 2 toward the inside of the barrel section 2.

[0041] Such a first irradiating section 110a can be a laser irradiating device that irradiates the first light, which is a laser beam.

[0042] On the other hand, the first irradiating section 110a can irradiate the first light along the first irradiation path R1a.

[0043] Such a first irradiation path R1a can be an optical path connecting the first irradiation unit 110a to the 1-1 reflection unit 120a.

[0044] The first-1 reflecting part 120a can reflect the first light irradiated by the first irradiating part 110a toward the lens part .

[0045] Such a first-first reflecting portion 120a can be a beam splitter.

[0046] On the other hand, the 1-1 reflecting portion 120a can reflect the first light to the 1-1 reflection path R2a.

[0047] Such a first-first reflection path R2a may be an optical path connecting the first-first reflection unit 120a to the lens unit .

[0048] Meanwhile, the first-first reflection path R2a may be parallel to the movement direction in which the lens unit 130 moves to control the focus.

[0049] For this purpose, the first-1 reflecting portion 120a may be provided at a predetermined angle and position so as to reflect the first light at a preset reflection angle.

[0050] The lens unit 130 can primarily refract the first light reflected by the first-first reflecting unit 120a toward the inspection object 3.

[0051] Meanwhile, the lens unit 130 can refract the first light to a first-first refraction path R3a.

[0052] Such a first-first refraction path R3a can be an optical path connecting the lens unit 130 to the inspection object 3.

[0053] Meanwhile, the angle formed by the 1-1 refracted path R3a with the moving direction may be included in a first angle range, where the angle formed by the 1-1 refracted path R3a with the moving direction is the smaller of the two angles formed by the 1-1 refracted path R3a with the moving direction, and the first angle range may be an angle range with a minimum angle greater than 0 degrees and a maximum angle less than 5 degrees.

[0054] Therefore, the lens unit 130 may be formed so that the refractive index of the first region through which the first light reflected from the first-1 reflecting unit 120a is incident and passes becomes a preset first refractive index.

[0055] Meanwhile, the first light refracted by the lens unit 130 is irradiated in the direction of the inspection object 3, and then reflected from the surface of the inspection object 3 to be irradiated to the lens unit 130 again.

[0056] At this time, the inspection object 3 can reflect the first light along the first-second reflection path R4a.

[0057] Such a first-second reflection path R4a can be an optical path connecting the inspection object 3 to the lens unit 130.

[0058] Thereafter, the lens unit 130 can secondarily refract the first light reflected by the inspection object 3 in the direction of the first-second reflecting unit 140a.

[0059] Meanwhile, the lens unit 130 can refract the first light to the first-second refraction path R5a.

[0060] Such a first-second refraction path R5a can be an optical path connecting the lens unit 130 to the first-second reflecting unit 140a.

[0061] Meanwhile, the angle formed by the first-second bent path R5a with the moving direction may be within the first angle range, where the angle formed by the first-second bent path R5a with the moving direction is the smaller of the two angles formed by the first-second bent path R5a with the moving direction, and the first angle range may be an angle range with a minimum angle greater than 0 degrees and a maximum angle less than 5 degrees.

[0062] To this end, the lens unit 130 may be formed so that the refractive index of the second region through which the first light reflected from the inspection object 3 is incident is a preset second refractive index.

[0063] The first-second reflecting portion 140 a can reflect the first light secondarily refracted by the lens portion 130 toward the focus control image sensor 150 .

[0064] The first and second reflecting parts 140a may be beam splitters.

[0065] On the other hand, the first-second reflecting portion 140a can reflect the first light to a first-third reflection path R6a.

[0066] Such a first-third reflection path R6a can be an optical path connecting the first-second reflection portion 140a to the focus control image sensor 150.

[0067] The focus control image sensor 150 can sense the first light reflected by the first-second reflecting portion 140a.

[0068] Specifically, the focus control image sensor 150 can sense the position on the sensor surface where the first light is irradiated.

[0069] Thereafter, the focus control image sensor 150 can output the sensed position of the first light to the control unit 160 as first light position data.

[0070] Such first light position data can be data that indicates the position where the first light is irradiated by coordinates, with the sensor surface being used as a coordinate system.

[0071] The process of irradiating, reflecting, refracting, and sensing the second light will be described below.

[0072] The second irradiating section 110b can irradiate the second light from the other side of the barrel section 2 toward the inside of the barrel section 2.

[0073] Such a second irradiating section 110b can be a laser irradiating device that irradiates the second light, which is a laser beam.

[0074] On the other hand, the second irradiating section 110b can irradiate the second light along the second irradiation path R1b.

[0075] Such a second irradiation path R1b can be an optical path connecting the second irradiation section 110b to the 2-1 reflection section 120b.

[0076] The 2-1 reflecting part 120b can reflect the second light irradiated by the second irradiating part 110b toward the lens part .

[0077] Such a second-first reflecting portion 120b can be a beam splitter.

[0078] On the other hand, the 2-1 reflecting portion 120b can reflect the second light along the 2-1 reflection path R2b.

[0079] Such a 2-1 reflection path R2b can be an optical path connecting the 2-1 reflection unit 120b to the lens unit 130.

[0080] Meanwhile, the second-first reflection path R2b may be parallel to the movement direction in which the lens unit 130 moves to control the focus.

[0081] For this purpose, the 2-1 reflecting portion 120b may be provided at a predetermined angle and position so as to reflect the second light at a preset reflection angle.

[0082] The lens unit 130 can primarily refract the second light reflected by the 2-1 reflecting unit 120b toward the inspection object 3.

[0083] On the other hand, the lens unit 130 can refract the second light to the second-1st refraction path R3b.

[0084] Such a 2-1 refraction path R3b can be an optical path connecting the lens unit 130 to the inspection object 3.

[0085] Meanwhile, the angle formed by the 2-1 refracted path R3b and the moving direction may be included in a second angle range, where the angle formed by the 2-1 refracted path R3b and the moving direction is the smaller of the two angles formed by the 2-1 refracted path R3b and the moving direction, and the second angle range may be an angle range with a minimum angle greater than 0 degrees and a maximum angle less than 5 degrees.

[0086] To this end, the lens unit 130 may be formed such that the refractive index of the third region, through which the second light reflected from the 2-1 reflecting unit 120b is incident and passes, is a preset third refractive index.

[0087] Meanwhile, the second light refracted by the lens unit 130 is irradiated in the direction of the inspection object 3, and then reflected from the surface of the inspection object 3 to be irradiated to the lens unit 130 again.

[0088] At this time, the inspection object 3 can reflect the second light along the 2-2 reflection path R4b.

[0089] Such a 2-2 reflection path R4b can be an optical path connecting the inspection object 3 to the lens unit 130.

[0090] Thereafter, the lens unit 130 can secondarily refract the second light reflected by the inspection object 3 in the direction of the 2-2 reflecting unit 140b.

[0091] On the other hand, the lens portion 130 can refract the second light to the 2-2 refraction path R5b.

[0092] Such a 2-2 refraction path R5b can be an optical path connecting the lens unit 130 to the 2-2 reflecting unit 140b.

[0093] Meanwhile, the angle formed by the 2-2 refraction path R5b with the movement direction may be within the second angle range described above, where the angle formed by the 2-2 refraction path R5b with the movement direction is the smaller of the two angles formed by the 2-2 refraction path R5b with the movement direction, and the second angle range may be an angle range with a minimum angle greater than 0 degrees and a maximum angle less than 5 degrees.

[0094] Therefore, the lens unit 130 can be formed so that the refractive index of the fourth region, through which the second light reflected from the inspection object 3 enters and passes, becomes a preset fourth refractive index.

[0095] The second-2 reflecting portion 140b can reflect the second light secondarily refracted by the lens portion 130 toward the focus control image sensor 150.

[0096] Such a second-second reflecting portion 140b can be a beam splitter.

[0097] On the other hand, the 2-2 reflecting portion 140b can reflect the second light to the 2-3 reflection path R6b.

[0098] Such a second-third reflection path R6b can be an optical path connecting the second-second reflection portion 140b to the focus control image sensor 150.

[0099] The focus control image sensor 150 can sense the second light reflected by the 2-2 reflecting portion 140b.

[0100] Specifically, the focus control image sensor 150 can sense the position on the sensor surface where the second light is irradiated.

[0101] Thereafter, the focus control image sensor 150 can output the sensed position of the second light to the control unit 160 as second light position data.

[0102] Such second light position data can be data that expresses the position where the second light is irradiated by coordinates using the sensor surface as a coordinate system.

[0103] Referring again to FIG. 4, the control unit 160 can control the separation distance between the lens unit 130 and the object to be inspected 3 based on first light position data, which is the position L1 of the first light sensed by the focus control image sensor 150, and second light position data, which is the position L2 of the second light.

[0104] Specifically, the control unit 160 can control the distance between the lens unit 130 and the object to be inspected 3 so that the position L1 of the first light is located within the first reference area A1 and the position L2 of the second light is located within the second reference area A2.

[0105] Specifically, the control unit 160 can control the separation distance between the lens unit 130 and the object to be inspected 3 by outputting a control signal to the lens barrel unit 2 to move the lens unit 130 vertically so that the position L1 of the first light is located within the first reference area A1 and the position L2 of the second light is located within the second reference area A2.

[0106] The distance between the inspection object 3 and the lens unit 130 shown in FIG. 3 may be the distance when the optical inspection device is in focus.

[0107] As a result, as shown in FIG. 4, the position L1 of the first light on the sensor surface can be located within the first reference area A1, and the position L2 of the second light can be located within the second reference area A2.

[0108] FIG. 5 is another example showing the inside of a focus control device of an optical inspection device according to one embodiment of the present invention and the path of light movement, and FIG. 6 is a diagram showing an example of light sensed by the focus control image sensor in FIG. 5.

[0109] Since the inspection object 3 shown in FIG. 5 is a thin object, the distance between the inspection object 3 and the lens unit 130 may be the distance when the optical inspection device is out of focus.

[0110] As a result, the first light and the second light are reflected by the object to be inspected 3 at an even lower position than in Figure 3, which changes the positions of the 1-2 reflection path R4a, the 1-2 refraction path R5a, the 1-3 reflection path R6a, the 2-2 reflection path R4b, the 2-2 refraction path R5b, and the 2-3 reflection path R6b compared to Figure 3, and the position L1 of the first light and the position L2 of the second light on the sensor surface can be moved as shown in Figure 6.

[0111] Thereafter, the control unit 160 outputs a control signal to the lens barrel unit 2 to move the lens unit 130 downward so that the position L1 of the first light is located within the first reference area A1 and the position L2 of the second light is located within the second reference area A2, thereby controlling the distance between the lens unit 130 and the object to be inspected 3 to be closer.

[0112] On the other hand, in another embodiment, when the position L1 of the first light is located outside the first reference area A1 and the position L2 of the second light is located in the second reference area A2, the control unit 160 can compare the length of the light separation distance, which is the separation distance between the position L1 of the first light and the position L2 of the second light, and the area separation distance, which is the shortest separation distance between the first reference area A1 and the second reference area A2.

[0113] Then, in another embodiment, the control unit 160 can output a control signal to the lens barrel unit 2 to move the lens unit 130 downward if the light separation distance is longer than the area separation distance, thereby controlling the separation distance between the lens unit 130 and the object to be inspected 3 to be closer.

[0114] In this case, the control unit 160 according to another embodiment can calculate an average separation distance, which is the average value of the first light-area separation distance, which is the shortest separation distance between the position L1 of the first light and the first reference area A1, and the second light-area separation distance, which is the shortest separation distance between the position L2 of the second light and the second reference area A2.

[0115] Then, in another embodiment, when the light separation distance is longer than the area separation distance, the control unit 160 can output a control signal to the lens barrel unit 2 to move the lens unit 130 further downward as the average separation distance becomes longer.

[0116] Conversely, in another embodiment, when the light separation distance is shorter than the area separation distance, the control unit 160 can output a control signal to the lens unit 2 to move the lens unit 130 upward, thereby controlling the separation distance between the lens unit 130 and the object to be inspected 3 to increase.

[0117] In this case, in another embodiment, when the light separation distance is shorter than the area separation distance, the control unit 160 can output a control signal to the lens barrel unit 2 to move the lens unit 130 further upward as the aforementioned average separation distance becomes longer.

[0118] Meanwhile, in yet another embodiment, the control unit 160 can calculate a separation distance difference, which is the difference between the first light-area separation distance, which is the shortest separation distance between the position L1 of the first light and the first reference area A1, and the second light-area separation distance, which is the shortest separation distance between the position L2 of the second light and the second reference area A2.

[0119] Then, in another embodiment, the control unit 160 can output an excessive thickness deviation signal to the outside when the difference in separation distance exceeds the reference distance, indicating that the thickness deviation of the object to be inspected 3 is too large to be suitable for inspection.

[0120] The present invention has been described with a focus on preferred embodiments. It will be understood by those skilled in the art that the present invention can be embodied in various modified forms without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is defined by the claims, not the foregoing description, and all variations within the scope of the claims should be construed as being within the scope of the present invention.

[0121] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it is of course possible for a person having ordinary skill in the art to which the present invention pertains to make various modifications and variations within the technical spirit of the present invention and the equivalent scope of the claims set forth below. [Explanation of symbols]

[0122] 100 Focus control device for optical inspection device 110a 1st irradiation section 120a 1st-1 reflection section 130 Lens section 140a 1st-2 reflection section 150 Focusing image sensor 110b 2nd irradiation section 120b 2-1 reflection section 140b 2nd-2nd reflection section

Claims

1. In a focus control device for an optical inspection device, a first irradiating unit that irradiates a first light from one side of a barrel of the optical inspection device, the barrel having an inspection image sensor attached to an upper portion thereof and a lens unit housed in an inner lower portion thereof, toward an inside of the barrel; a first-first reflecting unit that reflects the first light irradiated by the first irradiating unit toward a lens unit; a lens unit that primarily refracts the first light reflected by the first-1 reflecting unit toward an object to be inspected and secondarily refracts the first light reflected by the object to be inspected toward the first-2 reflecting unit; a first-second reflecting unit that reflects the first light secondarily refracted by the lens unit toward a focus control image sensor; a second irradiating unit that irradiates a second light from the other side of the barrel unit toward the inside of the barrel unit; a second-1 reflecting unit that reflects the second light irradiated by the second irradiating unit toward the lens unit; The lens portion is The second light reflected by the 2-1 reflecting unit is primarily refracted toward the object to be inspected, and the second light reflected by the object to be inspected is secondarily refracted toward the 2-2 reflecting unit, The focus control device of the optical inspection device includes: the second-second reflecting unit that reflects the second light secondarily refracted by the lens unit toward the focus control image sensor; A focus control device for an optical inspection device, further comprising a control unit that controls a separation distance between the lens unit and the object to be inspected based on first light position data, which is the position of the first light sensed by the focus control image sensor, and second light position data, which is the position of the second light.

2. The 1-1 reflection unit is reflecting the first light irradiated by the first irradiating unit along a first-1 reflection path toward the lens unit; The lens portion is 2. The focus control device for an optical inspection apparatus according to claim 1, wherein the first light reflected by the inspection object is secondarily refracted along a first-second refraction path toward the first-second reflecting portion.

3. The first-first reflection path is 3. The focus control device for an optical inspection device according to claim 2, wherein the focus control device is parallel to a moving direction in which the lens unit moves for controlling the focus.

4. The first-second bending path is 4. The focus control device for an optical inspection apparatus according to claim 3, wherein the angle formed with the moving direction is included in a first angle range.

5. The 2-1 reflection unit is reflecting the second light irradiated by the second irradiating unit along a second-1 reflection path toward the lens unit; The lens portion is 2. The focus control device for an optical inspection apparatus according to claim 1, further comprising: a second refracting unit for secondarily refracting the second light reflected by the inspection object along a second-second refraction path toward the second-second reflecting unit.

6. The 2-1 reflection path is 6. The focus control device for an optical inspection device according to claim 5, wherein the focus control device is parallel to a moving direction in which the lens unit moves for controlling the focus.

7. The second-second refraction path is 7. The focus control device for an optical inspection apparatus according to claim 6, wherein the angle formed with the moving direction is included in a second angle range.

8. The control unit 2. The focus control device of claim 1, wherein the distance between the lens unit and the object to be inspected is controlled so that the position of the first light is located within a first reference area and the position of the second light is located within a second reference area.

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