Focus control device for optical inspection equipment

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 apparatus. More specifically, the first light and the second light irradiated from the first irradiation unit and the second irradiation unit of the optical inspection apparatus are reflected in a path parallel to the moving direction in which the lens unit moves and passed through the lens unit. After passing through the lens unit and being refracted, the first light and the second light reflected from the inspection object are refracted again by the lens unit and reflected in the direction of the image sensor for focus control through the second reflection unit, so that the positions of the first light and the second light on the image sensor for focus control are sensed, and the separation distance from the inspection object is controlled based on the positions of the first light and the second light. The present invention relates to a focus control device for an optical inspection apparatus.

Background Art

[0002] Machine vision is a technology that endows a machine with the visual and judgment functions that humans have, and a system of hardware and software processes the functions of human perception and judgment instead.

[0003] Recently, with the conversion of various industrial fields to automation, machine vision is widely used according to the user's purpose not only for simple measurement in the production processes of almost all industries such as the semiconductor industry, aluminum, automobiles, mobile phones, logistics, pharmaceuticals, medical care, food and beverages, consumer goods, wood, textiles, glass, iron, casting, and chemicals, but also for the process of processing and judging the acquired images.

[0004] In particular, machine vision is applied to inspection equipment for detecting defects in semiconductor substrates and components. At the site of manufacturing semiconductors or LCDs, etc., the final product is completed through a large number of subdivided processes. Therefore, defects in components such as semiconductor substrates during the production process may cause serious problems that require the final product to be discarded later. To solve such problems, inspection equipment for detecting defects in semiconductor substrates and components at an appropriate time is used.

[0005] Generally, equipment such as high-resolution digital cameras or line scan cameras (which operate on a scanner-like principle) are primarily used to inspect semiconductors and other components. Line scan cameras, in particular, are widely used because they are advantageous for acquiring ultra-high-resolution images.

[0006] However, when using a digital camera or line scan camera, the image acquired will be either in focus or out of focus depending on the distance between the camera (specifically the lens) and the subject, and the inspection results will differ depending on the acquired image. Therefore, the most appropriate camera distance must be determined in advance through testing for each object being inspected.

[0007] However, conventional testing equipment is cumbersome because even changing the camera distance (i.e., focus) requires the tester to manually adjust it. This manual adjustment method is time-consuming and labor-intensive, making it difficult to maintain consistency in test results. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Korean Registered Patent Publication No. 10-0939541 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The object of the present invention is to provide a focus control device for an optical inspection device that controls the separation distance between the inspection object and the first and second beams of light emitted from the first and second irradiation units of the optical inspection device, reflects the first and second beams of light emitted from the first and second irradiation units, respectively, along a path parallel to the direction of movement of the lens unit, passes through the lens unit, is refracted after passing through the lens unit, and then the first and second beams of 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 and second beams of light on the focus control image sensor.

[0010] The objects of the present invention are not limited to those stated herein, and other objects and advantages of the present invention not mentioned herein may be understood from the following description and more clearly from the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention may be achieved by the means and combinations thereof shown in the claims. [Means for solving the problem]

[0011] The focus control device for an optical inspection apparatus according to the present invention comprises: a first irradiation unit that irradiates a first light from one side of the lens barrel of the optical inspection apparatus, which has an inspection image sensor for the optical inspection apparatus mounted on its upper part and a lens unit housed in the lower inner part, toward the inside of the lens barrel; a first-1 reflection unit that reflects the first light irradiated by the first irradiation unit toward the lens unit; a lens unit that first refracts the first light reflected by the first-1 reflection unit toward the object to be inspected and second refracts the first light reflected by the object to be inspected toward the first-2 reflection unit; a first-2 reflection unit that reflects the first light second refracted by the lens unit toward the focus control image sensor; and irradiates a second light from the other side of the lens barrel toward the inside of the lens barrel. The optical inspection apparatus includes a second irradiation unit and a second-first reflecting unit that reflects the second light irradiated by the second irradiation unit toward the lens unit, wherein the lens unit first refracts the second light reflected by the second-first reflecting unit toward the object to be inspected, and second refracts the second light reflected by the object to be inspected toward the second-second reflecting unit, and the focus control device of the optical inspection apparatus includes a second-second reflecting unit that reflects the second light second refracted by the lens unit toward the focus control image sensor, and a control unit that controls the 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, and second light position data, which is the position of the second light, sensed by the focus control image sensor.

[0012] The 1-1 reflecting portion reflects the first light irradiated by the first irradiating portion into the 1-1 reflection path toward the lens portion, and the lens portion can secondarily refract the first light reflected by the object being inspected into the 1-2 refraction path toward the 1-2 reflecting portion.

[0013] The 1-1 reflection path can be parallel to the direction of movement of the lens portion for controlling the focus.

[0014] The angle that the first- and second refraction paths make with the direction of movement falls within the first angular range.

[0015] The 2-1 reflecting portion reflects the second light irradiated by the 2 irradiating portion into the 2-1 reflection path toward the lens portion, and the lens portion can secondarily refract the second light reflected by the object being inspected into the 2-2 refraction path toward the 2-2 reflecting portion.

[0016] The 2-1 reflection path can be parallel to the direction of movement of the lens portion for controlling the focus.

[0017] The second-2 refraction path has an angle with respect to the direction of movement that falls within the second angular range.

[0018] The control unit can control the separation distance between the lens unit and the object to be inspected such that the position of the first light is located within the first reference area and the position of the second light is located within the 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 moving direction in which the lens unit moves and passed through the lens unit. After passing through the lens unit and being refracted, the first light and the second light reflected from the inspection object are refracted again by the lens unit and reflected in the direction of the focus control image sensor through the second reflection unit, so that the positions of the first light and the second light on the focus control image sensor are sensed, and the separation distance from the inspection object can be controlled based on the positions of the first light and the second light respectively.

Brief Description of the Drawings

[0020] [Figure 1] It is a perspective view of a focus control device of an optical inspection device according to an embodiment of the present invention. [Figure 2] It is a front view of a focus control device of an optical inspection device according to an embodiment of the present invention. [Figure 3] It is an example showing the inside of a focus control device of an optical inspection device according to an embodiment of the present invention and the light movement path. [Figure 4] It is a diagram showing an example of light sensed by the focus control image sensor in FIG. 3. [Figure 5] It is another example showing the inside of a focus control device of an optical inspection device according to an embodiment of the present invention and the light movement path. [Figure 6] It is a diagram showing an example of light sensed by the focus control image sensor in FIG. 5.

Modes for Carrying Out the Invention

[0021] Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include various modifications, equivalents, and / or alternatives of the embodiments of the present invention. Regarding the description of the drawings, similar reference numerals can be used for similar components.

[0022] In this specification, expressions such as “having,” “may have,” “include,” or “may include” refer to the presence of the relevant feature (e.g., numerical values, functions, operations, or components such as parts) and do not exclude the presence of additional features.

[0023] In this specification, expressions 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 cases where (1) at least one A is included, (2) at least one B is included, or (3) at least one A and at least one B are all included.

[0024] The terms “first,” “second,” “first,” or “second” used herein may modify various components regardless of their order and / or importance, and are used only to distinguish one component from others, without limiting the components in question. For example, the first user equipment and the second user equipment may represent different user equipment, regardless of their order or importance. For example, without departing from the scope of rights described herein, the first component may be named the second component, and similarly, the second component may be named by substituting for the first component.

[0025] When it is mentioned that a component (e.g., the first component) is "operally or communicatively coupled with" or "connected to" another component (e.g., the second component), it should be understood that the component is either directly connected to the other component or can be connected via another component (e.g., the third component). Conversely, when it is mentioned that a component (e.g., the first component) is "directly coupled" or "directly connected" to another component (e.g., the second component), it should be understood that there is no other component (e.g., the third component) between the first component and the other component.

[0026] As used herein, the expression "configured to" can be replaced, depending on the context, with other expressions such as "suitable for," "having the capacity to," "designed to," "adapted to," "made to," or "capable of." The term "configured to" does not necessarily mean only something that is "specifically designed to" in terms of hardware. Instead, in some contexts, the expression "device configured to" may mean that the device is "capable of" doing something together with other devices or components.

[0027] The terms used herein are used solely to describe specific embodiments and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as those generally understood by those ordinary skill in the art described herein. Terms used herein that are generally defined in dictionaries may be interpreted as having the same or similar meaning as they do in the context of the relevant art, and not in an ideal or overly formal sense unless explicitly defined herein. In some cases, terms defined herein may not be construed to exclude the embodiments described herein.

[0028] Figure 1 is a perspective view of a focus control device for an optical inspection apparatus according to one embodiment of the present invention, Figure 2 is a front view of the focus control device for an optical inspection apparatus according to one embodiment of the present invention, Figure 3 is an example showing the inside of the focus control device for an optical inspection apparatus 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] Referring to Figures 1 to 4, the focus control device 100 of the optical inspection apparatus according to one embodiment of the present invention is provided attached to the optical inspection apparatus and can control the focus of the optical inspection apparatus.

[0030] Such an optical inspection device could be a device that photographs the object to be inspected 3 and determines whether or not the object to be inspected 3 has defects.

[0031] For this purpose, the optical inspection device may include a cylindrical lens barrel 2 and an inspection image sensor 1 mounted on the upper part of the lens barrel 2.

[0032] On the other hand, the lens portion 130 of the focus control device 100 of the optical inspection apparatus according to one embodiment of the present invention can be located inside the lens barrel portion 2.

[0033] Specifically, the lens portion 130 can be located in the lower inner part of the lens barrel portion 2.

[0034] In this case, the lens barrel 2 is equipped with a motor, actuator, etc., which allows the lens section 130 located at the bottom to move vertically.

[0035] After the object to be inspected 3 is transferred to the lower part of the lens section 130 by the transfer device 4, it may be transferred to another area once the inspection is complete. Such a transfer device 4 may be a conveyor.

[0036] The focus control device 100 of the optical inspection apparatus according to one embodiment of the present invention can adjust the focus of the optical inspection apparatus 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 apparatus according to one embodiment of the present invention can adjust the focus of the optical inspection apparatus by controlling the separation distance between the lens unit 130 and the object to be inspected 3.

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

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

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

[0041] Such a first irradiation unit 110a could be a laser irradiation device that irradiates with a first light, which is laser light.

[0042] On the other hand, the first irradiation unit 110a can irradiate the first irradiation path R1a with the first light.

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

[0044] The first-1 reflecting section 120a can reflect the first light irradiated by the first irradiating section 110a in the direction of the lens section 130.

[0045] Such a first-first reflector 120a could be a beam splitter.

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

[0047] Such a first-first reflection path R2a can be an optical path connecting the first-first reflecting section 120a to the lens section 130.

[0048] On the other hand, the first reflection path R2a can be parallel to the direction of movement of the lens portion 130 in order to control the focus.

[0049] For this purpose, the first-1 reflecting section 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 portion 130 can cause the first light reflected by the 1-1 reflecting portion 120a to be primary refracted in the direction of the object to be inspected 3.

[0051] On the other hand, the lens section 130 can refract the first light into the first-to-first refraction path R3a.

[0052] Such a first-first refraction path R3a could be an optical path connecting the lens portion 130 to the object to be inspected 3.

[0053] On the other hand, the angle that the first-first refraction path R3a makes with the direction of movement may fall within the first angular range. Here, the angle that the first-first refraction path R3a makes with the direction of movement is the smaller of the two angles that the first-first refraction path R3a makes with the direction of movement, and the first angular range may be an angular range where the minimum angle is greater than 0 degrees and the maximum angle is less than 5 degrees.

[0054] Therefore, the lens portion 130 can be formed such that the refractive index of the first region through which the first light reflected from the first-1 reflecting portion 120a enters and passes is a preset first refractive index.

[0055] On the other hand, the first light, which is primary refracted by the lens portion 130, can be irradiated in the direction of the object to be inspected 3, and then reflected from the surface of the object to be inspected 3 and irradiated back onto the lens portion 130.

[0056] In this case, the object being inspected 3 can reflect the first light into the first-to-second reflection path R4a.

[0057] Such a first-to-second reflection path R4a could be an optical path connecting the object to be inspected 3 to the lens portion 130.

[0058] Subsequently, the lens portion 130 can cause the first light reflected by the object to be inspected 3 to undergo secondary refraction in the direction of the first-to-second reflecting portion 140a.

[0059] On the other hand, the lens section 130 can refract the first light into the first-to-second refraction path R5a.

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

[0061] On the other hand, the angle that the first-to-second refraction path R5a makes with the direction of movement may fall within the first angular range described above. Here, the angle that the first-to-second refraction path R5a makes with the direction of movement is the smaller of the two angles that the first-to-second refraction path R5a makes with the direction of movement, and the first angular range may be an angular range where the minimum angle is greater than 0 degrees and the maximum angle is less than 5 degrees.

[0062] For this purpose, the lens portion 130 may be formed such that the refractive index of the second region through which the first light reflected from the object to be inspected 3 is incident is a preset second refractive index.

[0063] The first-to-second reflecting section 140a can reflect the first light, which has been secondarily refracted by the lens section 130, in the direction of the focus control image sensor 150.

[0064] Such a first-to-second reflector 140a could be a beam splitter.

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

[0066] Such a first-to-third reflection path R6a could be an optical path connecting the first-to-second reflection section 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 section 140a.

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

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

[0070] Such first light position data could be data that uses the sensor surface as the coordinate system and represents the position where the first light was irradiated using coordinates.

[0071] The following describes the process by which the second light is irradiated, reflected, refracted, and sensed.

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

[0073] Such a second irradiation unit 110b could be a laser irradiation device that irradiates a second beam of light, which is laser light.

[0074] On the other hand, the second irradiation unit 110b can irradiate the second irradiation path R1b with second light.

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

[0076] The second-first reflecting section 120b can reflect the second light irradiated by the second irradiating section 110b in the direction of the lens section 130.

[0077] Such a second-first reflector 120b could be a beam splitter.

[0078] On the other hand, the second-first reflecting section 120b can reflect the second light into the second-first reflection path R2b.

[0079] Such a second-first reflection path R2b can be an optical path connecting the second-first reflecting section 120b to the lens section 130.

[0080] On the other hand, the second-first reflection path R2b can be parallel to the direction of movement in which the lens portion 130 moves to control the focus.

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

[0082] The lens portion 130 can cause the second light reflected by the second-first reflecting portion 120b to be primary refracted in the direction of the object to be inspected 3.

[0083] On the other hand, the lens section 130 can refract the second light into the second-first refraction path R3b.

[0084] Such a second-first refraction path R3b could be the optical path connecting the lens portion 130 to the object to be inspected 3.

[0085] On the other hand, the angle that the second-first refraction path R3b makes with the direction of movement may fall within the second angular range. Here, the angle that the second-first refraction path R3b makes with the direction of movement is the smaller of the two angles that the second-first refraction path R3b makes with the direction of movement, and the second angular range may be an angular range where the minimum angle is greater than 0 degrees and the maximum angle is less than 5 degrees.

[0086] For this purpose, the lens portion 130 may be formed such that the refractive index of the third region through which the second light reflected from the second-first reflecting portion 120b is incident is a predetermined third refractive index.

[0087] On the other hand, the second light, which has been primary refracted by the lens portion 130, can be irradiated in the direction of the object to be inspected 3, and then reflected from the surface of the object to be inspected 3 and irradiated back onto the lens portion 130.

[0088] At this time, the object being inspected 3 can reflect the second light into the second-second reflection path R4b.

[0089] Such a second-second reflection path R4b could be an optical path connecting the object to be inspected 3 to the lens section 130.

[0090] Subsequently, the lens portion 130 can cause the second light reflected by the object to be inspected 3 to undergo secondary refraction in the direction of the second-second reflecting portion 140b.

[0091] On the other hand, the lens section 130 can refract the second light into the second-second refraction path R5b.

[0092] Such a second-second refraction path R5b could be an optical path connecting the lens section 130 to the second-second reflecting section 140b.

[0093] On the other hand, the angle that the second-second refraction path R5b makes with the direction of movement may fall within the second angular range described above. Here, the angle that the second-second refraction path R5b makes with the direction of movement is the smaller of the two angles that the second-second refraction path R5b makes with the direction of movement, and the second angular range may be an angular range where the minimum angle is greater than 0 degrees and the maximum angle is less than 5 degrees.

[0094] Therefore, the lens portion 130 can be formed such that the refractive index of the fourth region through which the second light reflected from the object to be inspected 3 enters and passes is a predetermined fourth refractive index.

[0095] The second-second reflecting section 140b can reflect the second light, which has been secondarily refracted by the lens section 130, in the direction of the focus control image sensor 150.

[0096] Such a second-second reflector 140b could be a beam splitter.

[0097] On the other hand, the second-second reflector 140b can reflect the second light into the second-third reflection path R6b.

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

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

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

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

[0102] Such second light position data could be data that uses the sensor surface as the coordinate system and represents the position where the second light was irradiated using coordinates.

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

[0104] Specifically, the control unit 160 can control the separation distance between the lens unit 130 and the object to be inspected 3 such that the position L1 of the first light is located within the first reference region A1 and the position L2 of the second light is located within the second reference region 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 that moves 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 separation distance between the object to be inspected 3 and the lens unit 130 shown in Figure 3 may be the separation distance when the optical inspection device is in focus.

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

[0108] Figure 5 is another example showing the interior of the focus control device and the light path of an optical inspection apparatus according to one embodiment of the present invention, and Figure 6 shows an example of light sensed by the focus control image sensor in Figure 5.

[0109] Since the object to be inspected 3 shown in Figure 5 is a thin object, the separation distance between the object to be inspected 3 and the lens unit 130 may be the separation distance when the optical inspection device is not in focus.

[0110] As a result, the first and second beams are reflected by the object 3 at an even lower position than in Figure 3, changing the positions of the first-to-second reflection path R4a, the first-to-second refraction path R5a, the first-to-third reflection path R6a, the second-to-second reflection path R4b, the second-to-second refraction path R5b, and the second-to-third reflection path R6b compared to Figure 3. This can cause the positions L1 of the first beam and L2 of the second beam on the sensor surface to shift, as shown in Figure 6.

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

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

[0113] Subsequently, in the other embodiment, the control unit 160 can output a control signal to the lens barrel 2 to move the lens unit 130 downwards if the optical 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 reduced.

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

[0115] Subsequently, in the control unit 160 of the other embodiment, if the optical separation distance is longer than the regional separation distance, it can output a control signal to the lens barrel 2 that moves the lens unit 130 further downward as the average separation distance increases.

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

[0117] In this case, the control unit 160 according to the other embodiment can output a control signal to the lens barrel 2 that moves the lens unit 130 upwards more as the average separation distance increases, when the optical separation distance is shorter than the area separation distance.

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

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

[0120] We have carefully examined the present invention, focusing on preferred embodiments. Those with ordinary skill in the art to which the present invention pertains will understand that the present invention can be practiced in modified forms without departing from its essential characteristics. Therefore, the disclosed embodiments should be considered in an explanatory rather than restrictive manner. The scope of the present invention is defined in the claims, not in the foregoing description, and all differences within an equivalent scope should be construed as being included within the present invention.

[0121] As described above, although the present invention has been explained by limited embodiments and drawings, the present invention is not limited thereto, and of course, various modifications and variations are possible by persons with ordinary skill in the art to which the present invention pertains, within the equivalent scope of the technical concept of the present invention and the claims described below. [Explanation of symbols]

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

Claims

1. In a control device for the focus of an optical inspection device, An inspection image sensor for the optical inspection device is mounted on the upper part of the optical inspection device, and a lens unit is housed in the lower inner part of the lens barrel of the optical inspection device. A first irradiation unit irradiates first light from one side of the lens barrel in the direction of the inside of the lens barrel, A first-first reflecting unit that reflects the first light irradiated by the first irradiating unit toward the lens unit, A lens section that first refracts the first light reflected by the 1-1 reflector in the direction of the object to be inspected, and secondarily refracts the first light reflected by the object to be inspected in the direction of the 1-2 reflector, A first-to-second reflecting section that reflects the first light, which has been secondarily refracted by the lens section, in the direction of the image sensor for focus control, A second irradiation unit that irradiates a second light into the inside of the lens barrel from the other side of the lens barrel, It includes a second-first reflecting section that reflects the second light irradiated by the second irradiating section in the direction of the lens section, The aforementioned lens portion is The second light reflected by the 2-1 reflector is first refracted in the direction of the object to be inspected, and the second light reflected by the object to be inspected is second refracted in the direction of the 2-2 reflector. The focus control device of the aforementioned optical inspection apparatus is The second-2 reflecting section reflects the second light, which has been secondarily refracted by the lens section, in the direction of the focus control image sensor, The system further includes a control unit that controls the 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, and second light position data, which is the position of the second light, sensed by the focus control image sensor, and outputs a thickness deviation excess signal to the outside to indicate that the thickness deviation of the object to be inspected is too large to be suitable for optical inspection. The control unit, If the position of the first light is outside the first reference region and the position of the second light is outside the second reference region, the separation distance between the lens portion and the object to be inspected is controlled so that the position of the first light is within the first reference region and the position of the second light is within the second reference region. When the position of the first light is located outside the first reference region and the position of the second light is located outside the second reference region, the control unit performs the separation distance control as follows: The optical separation distance, which is the distance between the position of the first light and the position of the second light, and the region separation distance, which is the shortest distance between the first reference region and the second reference region, are compared in terms of their relative lengths. The average separation distance is calculated as the average of the first light-to-region separation distance, which is the shortest separation distance between the position of the first light and the first reference region, and the second light-to-region separation distance, which is the shortest separation distance between the position of the second light and the second reference region. If the optical separation distance is longer than the area separation distance, the longer the average separation distance, the more control signals are output to the lens barrel to move the lens portion downwards, thereby controlling the separation distance to bring the lens portion closer to the object to be inspected. If the optical separation distance is shorter than the area separation distance, the system controls the separation distance by outputting a control signal to the lens barrel that moves the lens portion upward as the average separation distance increases, thereby moving the lens portion and the object to be inspected further apart. The output of the thickness deviation excess signal performed by the control unit is: The separation distance difference, which is the difference between the first optical-domain separation distance and the second optical-domain separation distance, is calculated. A focus control device for an optical inspection apparatus, characterized in that it outputs the thickness deviation excess signal to the outside when the separation distance difference exceeds a reference distance.

2. The 1-1 reflective section is, The first light irradiated by the first irradiation unit is reflected into the first reflection path toward the lens portion. The aforementioned lens portion is The focus control device for an optical inspection apparatus according to claim 1, characterized in that it causes the first light reflected by the object to be inspected to undergo secondary refraction in the first-second refraction path toward the first-second reflecting portion.

3. The first reflection path described above is: The focus control device for an optical inspection apparatus according to claim 2, characterized in that it is parallel to the direction of movement of the lens portion for controlling the focus.

4. The first and second refraction paths described above are: The focus control device for an optical inspection apparatus according to claim 3, characterized in that the angle it makes with the direction of movement is included in a first angular range.

5. The 2-1 reflective section is, The second light irradiated by the second irradiation unit is reflected into the second-first reflection path toward the lens portion. The aforementioned lens portion is The focus control device for an optical inspection apparatus according to claim 1, characterized in that it causes the second light reflected by the object to be inspected to undergo secondary refraction in the second-second refraction path toward the second-second reflecting portion.

6. The second-first reflection path is: The focus control device for an optical inspection apparatus according to claim 5, characterized in that it is parallel to the direction of movement of the lens portion for controlling the focus.

7. The second-to-second refraction path is, The focus control device for an optical inspection apparatus according to claim 6, characterized in that the angle it makes with the aforementioned direction of movement is included in the second angular range.

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