Inspection-use optical device and illumination optical system therefor

Abstract

Provided is an inspection-use optical device for a solid-state imaging element, wherein in order to control the angles of main light rays, upper light rays, and lower light rays at each image height so that the angles manifest respective prescribed characteristics, the inspection-use optical device includes: an aperture having an opening 19 through which diffused light passes; and an illumination optical system 21 into which the light that passed through the aperture enters and which projects inspection light onto the solid-state imaging element. The illumination optical system 21 includes first and second aspherical lenses 23, 25. The first aspherical lens 23 has negative power in an annular region 23A on the peripheral edge side, and has positive power in a disk-shaped region 23B closer to the optical axis. The second aspherical lens 25 has positive power in an annular region 25A on the peripheral edge side, and has negative power in a disk-shaped region 5B closer to the optical axis.

Description

Optical inspection device and illumination optical system therefor

[0001] The present invention relates to an optical inspection device for irradiating inspection light onto the light receiving surface of a solid-state image sensor, such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

[0002] One such optical system is disclosed in Patent Document 1. The optical system described in Patent Document 1 has a single aspherical lens between an aperture stop and an illumination position. This aspherical lens irradiates the illumination position (corresponding to the light-receiving surface of an image sensor) with inspection light having a predetermined CRA (chief ray angle) characteristic. For example, the predetermined CRA characteristic disclosed is one in which the CRA increases roughly in the form of a saturation curve as the image height increases.

[0003] Japanese Patent Application Publication No. 2022-145349

[0004] All-pixel autofocus technology, Sony Semiconductor Solutions Group, https: / / www.sony-semicon.com / ja / technology / mobile / autofocus.html

[0005] Non-Patent Document 1 discloses several structures of an autofocus image sensor, such as a structure having two photodiodes under one on-chip lens and a structure having four photodiodes arranged in a 2 × 2 matrix under one on-chip lens.

[0006] In testing an autofocus image sensor having multiple photodiodes under one on-chip lens, in addition to the requirement that the test light have predetermined CRA characteristics, one or more additional conditions must also be satisfied.

[0007] One of the main additional conditions is that, at each image height position (position of each on-chip lens) of the image sensor, the amount of light in the upper bundle of rays from the chief ray to the upper ray of the inspection light (i.e., the bundle of rays that have passed through the upper half of the aperture stop) and the amount of light in the lower bundle of rays from the chief ray to the lower ray (i.e., the bundle of rays that have passed through the lower half of the aperture stop) are substantially equal. To satisfy this main additional condition, the upper ray angle and the lower ray angle each need to meet predetermined characteristics according to the image height.

[0008] In short, to inspect an autofocus image sensor that has multiple photodiodes under one on-chip lens, the inspection light is required to meet the respective predetermined characteristics according to the image height, not only for the CRA but also for the upper and lower ray angles.

[0009] However, there is no mention of the above additional condition in Patent Document 1. Furthermore, according to research by the inventors of the present invention, it is difficult to satisfy the above additional condition with a configuration such as that described in Patent Document 1, which has only one aspherical lens between the aperture stop and the irradiation position.

[0010] To satisfy the above additional conditions, it may be possible to use a complex lens system including many lenses, but from the viewpoint of manufacturing costs, it is more desirable to satisfy the above requirements with a simple configuration having as few lenses as possible.

[0011] One object is to enable an inspection optical device to control the angles of the chief ray, upper ray, and lower ray at each image height to have predetermined characteristics.

[0012] Another object is to realize an inspection optical device suitable for inspecting autofocus image sensors using as few lenses as possible.

[0013] An optical inspection device according to one embodiment of the present invention is an optical inspection device for irradiating inspection light onto the light receiving surface of a solid-state imaging element, and comprises: an aperture having an aperture that passes diffused light; and an illumination optical system that inputs the light that has passed through the aperture and irradiates a predetermined illumination surface with the inspection light; the illumination optical system comprises a first aspherical lens and a second aspherical lens; the first aspherical lens has a first concave lens region that is a circular ring-shaped region on the peripheral side far from the optical axis and has negative power; and a first convex lens region that is a disk-shaped region closer to the optical axis than the first concave lens region and has positive power; and the second aspherical lens has a second convex lens region that is a circular ring-shaped region on the peripheral side far from the optical axis and has positive power; and a second concave lens region that is a disk-shaped region closer to the optical axis than the second convex lens region and has negative power.

[0014] According to the present invention, in an optical inspection device, the angles of the chief ray, upper ray, and lower ray at each image height can be well controlled to their respective predetermined characteristics. Also, according to the present invention, an optical inspection device suitable for inspecting autofocus image sensors can be realized using as few lenses as possible.

[0015] FIG. 1 shows a longitudinal cross-sectional configuration of an optical inspection device according to an embodiment, taken along the optical axis. FIG. 2 shows a cross-sectional structure of an illumination lens system taken along the optical axis. FIG. 3 more specifically shows the aspheric shapes of the entrance and exit surfaces of the first and second lenses. FIG. 4 more specifically shows the thickness variations of the first and second lenses. FIG. 5 shows the path of a ray bundle entering the illumination lens system through the center of the aperture of the diaphragm. FIG. 6 shows the path of a ray bundle entering the illumination lens system through the upper edge of the aperture of the diaphragm. FIG. 7 shows the path of a ray bundle entering the illumination lens system through the lower edge of the aperture of the diaphragm. FIG. 8 shows the path of a ray bundle entering the center of the illumination surface (image height is zero). FIG. 9 shows the path of a ray bundle entering the edge of the illumination surface (image height is maximum). FIG. 10 shows the path of a ray bundle entering an intermediate position on the illumination surface (image height is intermediate). Fig. 11 shows the ray paths of the illumination lens system according to the embodiment and the single-lens illumination lens system according to the prior art, compared. Fig. 12 shows the CRA, upper ray angle, and lower ray characteristics of the illumination surface of the illumination optical system according to the embodiment and the single-lens illumination optical system, compared. Fig. 13 shows the preferred ranges of sag and thickness of the first lens and the second lens.

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to this embodiment. In addition, in the description of the drawings, the same parts are designated by the same reference numerals. In addition, although terms such as "first," "second," and "third" may be used to describe various elements or components in this disclosure, it will be understood that these elements or components should not be limited by these terms. These terms are used only to distinguish one element or component from another element or component. Therefore, a first element or component discussed below could also be referred to as a second element or component without departing from the teachings of the inventive concept.

[0017] 1 shows a longitudinal cross-sectional configuration of an inspection optical device according to an embodiment, taken along the optical axis. The inspection optical device 1 has a hollow cylindrical lens barrel 3. During inspection, the light-receiving surface of an image sensor to be inspected is placed on an irradiation surface 7 shown at the right end of the figure. During inspection, an input light beam (e.g., telecentric light) 5 from a light source device (not shown) enters the lens barrel 3 from the left side of the figure, passes through the lens barrel 3, is adjusted to an inspection light beam that satisfies certain conditions, and is then irradiated onto the irradiation surface 7 (i.e., the light-receiving surface of the image sensor).

[0018] Arranged within the lens barrel 3, in order from the input side to the output side, are a pre-stage optical system 11, an aperture stop 17, and an illumination lens system 21 (illumination optical system). The aperture stop 17 has a circular opening 19 when viewed from the front. The pre-stage optical system 11 converts an input light beam 5 from a light source into a divergent light beam that diverges at any position within the opening 19 of the aperture stop 17. The specific configuration of the pre-stage optical system 11 is not shown, but various variations are possible, and for example, a known or commonly used configuration may be adopted. The divergent light beam that leaves the pre-stage optical system 11 and passes through the opening 19 enters the illumination lens system 21. The illumination lens system is composed of only two lenses, 23 and 25. The lens 23 arranged on the input side will be referred to as the "first lens" hereinafter, and the lens 25 arranged on the output side will be referred to as the "second lens" hereinafter.

[0019] Figure 2 shows a cross-sectional structure along the optical axis of the illumination lens system. In Figure 2, the straight line on the left indicates the aperture 19 of the aperture stop 17, and the straight line on the right indicates the illumination surface 7 (on which the light-receiving surface of the image sensor is placed during inspection). The inspection light beam enters from the left of the figure and passes through the aperture 19 and the illumination lens system 21 in that order to reach the illumination surface 7.

[0020] The illumination lens system 21 is a non-imaging optical system. The first lens 23 and the second lens 25 are each a non-imaging aspherical lens having a disk shape centered on the optical axis 31. In the drawing, the dotted auxiliary lines 23C and 25C of each lens 23 and 25 indicate the outer edges of the effective lens area, and only the lens area inside these lines functions as a lens. In the following description, the terms "first lens 23" and "second lens 25" refer to the effective lens area of ​​each lens.

[0021] First lens 23 has a circular annular region 23A (shown with a matte finish in the drawing) near the periphery centered on optical axis 31, which has negative power and functions as a concave lens, and a disk-shaped region 23B (shown with a white background in the drawing) closer to optical axis 31 than this periphery region has positive power and functions as a convex lens. In this way, first lens 23 has a region 23A that functions as a concave lens on the periphery side (hereinafter referred to as the "first concave lens region") and a region 23B that functions as a convex lens closer to the center (hereinafter referred to as the "first convex lens region")

[0022] The second lens 25 has a circular annular region 25A (shown as a white background in the drawing) close to the periphery centered on the optical axis 31, which has positive power and functions as a convex lens, and a disk-shaped region 25B (shown as a matte background in the drawing) closer to the optical axis 31 than the peripheral region has negative power and functions as a concave lens. In this way, the second lens 25 has a region 25A (hereinafter referred to as the "second convex lens region") that functions as a convex lens on the peripheral side, and a region 25B (hereinafter referred to as the "second concave lens region") that functions as a concave lens closer to the center.

[0023] In the first lens 23, the boundary between the first concave lens region 23A and the first convex lens region 23B is shown as a simple line (surface) in the figure. However, in reality, the power of the lens 23 differs if the angle of incidence of a ray of light incident on the same point on the entrance surface of the lens 23 differs, so the boundary between the concave and convex lens regions 23A and 23B is not a line (surface) as shown, but exists in a radial range with a certain width near the line (surface). The same is true for the boundary between the convex and concave lens regions 25A and 25B of the second lens 25.

[0024] Furthermore, the power of both the first lens 23 and the second lens 25 changes smoothly and steplessly (that is, without steps) according to the radial position r from the optical axis 31 .

[0025] In this way, the first lens 23 and the second lens 25 have mutually opposite arrangements of positive and negative powers (concave lens regions and convex lens regions) according to the radial position r.

[0026] Therefore, in the peripheral region of the illumination lens system 21 far from the optical axis 31, the first concave lens region 23A is arranged first, followed by the second convex lens region 25A in order of passage of light rays (this region with concave and convex lens arrangement will be referred to below as the "reverse telephoto region").

[0027] Furthermore, in the central region of the illumination lens system 21 closer to the optical axis 31, the first convex lens region 23B is arranged first, followed by the second concave lens region 25B in order of light ray passage (this region with a convex-concave lens arrangement will be referred to below as the "telephoto region").

[0028] The terms "reverse telephoto" and "telephoto" are generally used in relation to imaging optical systems, and their use in the non-imaging type illumination lens system 21 may not be strictly appropriate. However, in this specification, we will use these terms to clearly explain the configuration of the lens system.

[0029] In this way, the illumination lens system 21 has an inverted telephoto region on the peripheral side (a set of the first concave lens region 23A and the second convex lens region 25A) and a more central telephoto region (a set of the first convex lens region 23B and the second concave lens region 25B).

[0030] 3 shows in more detail the aspheric shapes of the entrance and exit surfaces of the first and second lenses. In the figure, the maximum effective radius of entrance surface 23C of first lens 23 is indicated by R11, and the maximum effective radius of exit surface 23D is indicated by R12. The maximum effective radius of entrance surface 25C of second lens 25 is indicated by R21, and the maximum effective radius of exit surface 25D is indicated by R22. The relative sizes of these radii are R11<R12<R21<R22.

[0031] The symbols Z1 and Z2 respectively indicate the sag (the length indicating how far the lens surface protrudes or recesses from the vertex of the surface) of the exit surface 23D of the first lens 23 and the exit surface 25D of the second lens 25. The values ​​of sag Z1 and Z2 are zero at the center point (optical axis position) of each exit surface, and are positive on the entrance side and negative on the exit side.

[0032] The sag of the first lens 23 is as follows: The sag of the incident surface 23C monotonically increases as the radial position r increases up to the maximum effective radius R11. In other words, the incident surface 23C is curved so as to bulge more toward the output side as the radial position r decreases.

[0033] As the radial position r increases, the sag Z1 of the exit surface 23D increases up to a first radial position R13 near the periphery, and then decreases from the first radial position R13 to the maximum effective radius R12. In other words, as the radial position r decreases, the exit surface 23D curves so that it first recesses toward the entrance side and then protrudes more toward the exit side. The first radial position R13 where the sag Z1 changes from increasing to decreasing is hereinafter referred to as the "inflection point of sag Z1."

[0034] The sag of the second lens 25 is as follows: The sag of the incident surface 25C monotonically increases as the radial position r increases. In other words, the incident surface 25C curves so that it protrudes more toward the output side as the radial position r decreases.

[0035] As the radial position r increases, the sag Z2 of the exit surface 25D gradually decreases toward the negative side until it reaches the second radial position R23, then begins to increase from the second radial position R23. At the larger third radial position R24, the sag Z2 transitions from negative to positive, increasing until it reaches the maximum effective radius R22. In other words, as the radial position r decreases, the exit surface 25D curves, first bulging toward the exit side and then gently recessing toward the entrance side. The second radial position R23, where the sag Z2 transitions from decreasing to increasing, is hereinafter referred to as the "inflection point of sag Z2," and the third radial position R24, where the sag Z2 transitions from negative to positive, is hereinafter referred to as the "transition point of sag Z2."

[0036] Figure 4 shows the change in thickness of the first and second lenses in more detail. As shown in Figure 4, the thickness T1 of the first lens 23 (measured in a direction parallel to the optical axis) decreases as the radial position r increases to a fourth radial position R15, and then begins to increase from the fourth radial position R15 until it reaches the maximum effective radius R11 of the entrance surface 23C. The fourth radial position R15, where the thickness T1 changes from decreasing to increasing, is hereinafter referred to as the "inflection point of thickness T1."

[0037] As the radial position r increases, the thickness T2 of the second lens 25 (measured in a direction parallel to the optical axis) increases up to a fifth radial position R25, and then begins to decrease from the fifth radial position R25 until it reaches the maximum effective radius R21 of the incident surface 25C. The fifth radial position R25 where the thickness T2 changes from increasing to decreasing is hereinafter referred to as the "inflection point of the thickness T2."

[0038] Depending on the design of the second lens 25, the inflection point of the thickness T2 may not exist within the maximum effective radius R21 of the entrance surface 25C (that is, the thickness T2 may continue to increase up to the maximum effective radius R21).

[0039] Figure 5 shows the path of a bundle of rays entering the illumination lens system through the center of the aperture of the diaphragm, Figure 6 shows the path of a bundle of rays entering the illumination lens system through the top edge of the aperture of the diaphragm, and Figure 7 shows the path of a bundle of rays entering the illumination lens system through the bottom edge of the aperture of the diaphragm.

[0040] As shown in Figures 5 to 7, a bundle of rays entering the reverse telephoto region on the peripheral side of the illumination lens system 21 is first refracted away from the optical axis by the concave lens action of the first lens 23, and then refracted toward the optical axis by the convex lens action of the second lens 25.

[0041] A bundle of rays entering the central telephoto region of the illumination lens system 21 is first refracted by the convex lens action of the first lens 23 so as to approach the optical axis, and then by the concave lens action of the second lens 25 so as to move away from the optical axis.

[0042] As a result of the refraction of the light beams described above, examples of the paths of the light beams incident on each image height position h on the irradiation surface 7 are shown in FIGS. 8 to 10. FIG. 8 shows the path of the light beam incident on the center of the irradiation surface (image height is zero). FIG. 9 shows the path of the light beam incident on the edge of the irradiation surface (image height is maximum). FIG. 10 shows the path of the light beam incident on an intermediate position on the irradiation surface (image height is intermediate).

[0043] As shown in Figures 8 to 10, at any image height position h, the difference in light quantity between the upper half of the ray bundle from the chief ray CR to the upper ray UR (the ray bundle incident from the upper half region 19A of the opening 19) and the lower half of the ray bundle from the chief ray CR to the lower ray LR (the ray bundle incident from the lower half region 19B of the opening 19) is very small (i.e., they are substantially equal).

[0044] FIG. 11 shows the paths of the ray bundles shown in FIGS. 8 to 10 through the two-lens illumination lens system 21 of this embodiment in comparison with the paths of the ray bundles through a single-lens illumination lens system 121 according to the prior art.

[0045] Both the illumination lens system 21 according to this embodiment shown in Fig. 11 and the illumination lens system 121 according to the prior art are designed to achieve the same target characteristics of CRA, upper ray angle, and lower ray angle on the illumination surfaces 7 and 107. Here, the target characteristics are, for example, those shown by the solid curves in Fig. 12.

[0046] As can be seen from FIG. 11, with the single lens system 121, the difference between the amount of light in the upper half of the ray bundle from the chief ray to the upper ray and the amount of light in the lower half of the ray bundle from the chief ray to the lower ray tends to become larger as the image height position h increases.

[0047] In contrast, with the illumination lens system 21 according to this embodiment, the difference between the amount of light in the upper half ray bundle and the amount of light in the lower half ray bundle is much smaller than with the illumination lens system 121 at all image height positions h.

[0048] This difference in performance will be described in more detail with reference to Fig. 12. Fig. 12 shows a comparison of the CRA, upper ray angle, and lower ray characteristics of the illumination surface between the illumination optical system of the embodiment and the illumination optical system with a single lens.

[0049] 12, solid curves 51, 53, and 55 respectively represent the target CRA curve, upper ray angle curve, and lower ray angle curve according to the image height position h. These target angular characteristics are determined according to the specifications of the image sensor to be inspected. In the case of an autofocus image sensor, the angular distance between the target CRA curve 51 and the target upper ray angle curve 53 and the angular distance between the target CRA curve 51 and the target lower ray angle curve 55 are determined so that the light amounts of the upper half ray bundles and the lower half ray bundles described above are substantially the same at all image height positions h.

[0050] With the single lens system 121, the target CRA curve 51 can be met with high precision, but the realized upper and lower ray angle curves are as shown by dashed lines 63 and 65, respectively. That is, for example, as the image height position h increases, the realized upper ray angle curve 63 becomes smaller than the target curve 53, and the realized lower ray angle curve 65 becomes smaller than the target curve 55.

[0051] The illumination lens system 21 according to this embodiment can accurately achieve the target CRA curve 51, upper ray angle curve 53, and lower ray angle curve 55 (for example, within an error of 1 degree from the target curves). This performance makes it easy to meet the requirements for inspecting autofocus image sensors.

[0052] Furthermore, since the above performance can be obtained with only two aspherical lenses 23 and 25, it is also advantageous in terms of manufacturing costs.

[0053] 11, the diameter of the diaphragm opening 19 used in the illumination lens system 21 according to this embodiment can be made larger than the diameter of the diaphragm opening 119 used in the single lens system 121 according to the prior art. This has the advantage of making it easier to control the amount of light provided to the illumination surface.

[0054] The set of target CRA curve 51, target upper ray angle curve 53, and target lower ray angle curve 55 shown in Figure 12 is an example suitable for a particular specification of an image sensor. If the specification of the image sensor differs, the specific values ​​of the set of target angle curves will differ, but the variation of the set of target angle curves should fall within a certain distribution range.

[0055] The inventors used a computer optical simulator to design an embodiment of the illumination lens system 21 that is optimal (within an error of 1 degree relative to the set of target angle curves) for each of different sets of target angle curves that exist within the known distribution range.

[0056] FIG. 13 shows, for five of the examples, the positions of the inflection point R13 of the sag Z1 and the inflection point R15 of the thickness T1 of the first lens 23 shown in FIGS. 3 and 4 , as well as the inflection point R23 of the sag Z2, the transition point R24 of the sag Z2, and the inflection point R25 of the thickness T2 of the second lens 25.

[0057] From this simulation, it was found that in order to control the CRA curve, upper ray angle curve, and lower ray angle curve to their respective target angle curves with an error of 1 degree or less, it is preferable to design the inflection point R13 of the sag Z1 and the inflection point R15 of the thickness T1 of the first lens 23 shown in Figures 3 and 4, and the inflection point R23 of the sag Z2 of the second lens 25, within the following ranges.

[0058] (1) The inflection point R13 of the sag Z1 of the exit surface 23D of the first lens is preferably within a range of 70% to 98% of the maximum effective radius R12 of the exit surface 23D. (2) The inflection point R15 of the thickness T1 of the first lens is preferably within a range of 35% to 95% of the maximum effective radius R11 of the entrance surface 23C. (3) The inflection point R23 of the sag Z2 of the exit surface 25D of the second lens is preferably within a range of 30% to 55% of the maximum effective radius R22 of the exit surface 25D. (4) The transition point R24 of the sag Z2 of the exit surface 25D of the second lens is preferably within a range of 45% to 85% of the maximum effective radius R22 of the exit surface 25D. (5) The inflection point R25 of the thickness T2 of the second lens is preferably within a range of 90% or more of the maximum effective radius R21 of the entrance surface 25C.

[0059] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention.

[0060] DESCRIPTION OF SYMBOLS 1: Inspection optical device 3: Lens barrel 7: Irradiation surface 11: Pre-stage optical system 17: Aperture stop 19: Aperture 19A: Upper half region 19B: Lower half region 21: Illumination lens system (illumination optical system) 23: First aspherical lens 23A: First concave lens region 23B: First convex lens region 23C: Incident surface 23D: Exit surface 25: Second aspherical lens 25A: Second convex lens region 25B: Second concave lens region 25C: Incident surface 25D: Exit surface 31: Optical axis R11: Maximum effective radius R12: Maximum effective radius R13: First radial position R15: Fourth radial position R21: Maximum effective radius R22: Maximum effective radius R23 : Second radial position R24: Third radial position R25: Fifth radial position T1: Thickness T2: Thickness UR: Upper ray Z1: Sag Z2: Sag h: Image height position r: Radial position

Claims

1. In an inspection optical device for irradiating an inspection light onto a light receiving surface of a solid-state imaging device, the inspection optical device includes a diaphragm having an aperture for passing diffused light, and an illumination optical system that inputs the light passing through the diaphragm and irradiates the inspection light onto a predetermined irradiation surface. The illumination optical system includes a first aspherical lens and a second aspherical lens. The first aspherical lens includes a first concave lens region that is an annular region on the peripheral side far from the optical axis and has a negative power, and a first convex lens region that is a disk-shaped region closer to the optical axis than the first concave lens region and has a positive power. The second aspherical lens includes a second convex lens region that is an annular region on the peripheral side far from the optical axis and has a positive power, and a second concave lens region that is a disk-shaped region closer to the optical axis than the second convex lens region and has a negative power.

2. When the maximum effective radius of the incident surface of the first aspherical lens is R11, the maximum effective radius of the exit surface of the first aspherical lens is R12, the maximum effective radius of the incident surface of the second aspherical lens is R21, and the maximum effective radius of the exit surface of the second aspherical lens is R22, the inspection optical device according to claim 1, which satisfies the condition of R11 < R12 < R21 < R22.

3. The sag of the incident surface of the first aspherical lens monotonically increases up to the maximum effective radius as the radius position increases. The sag of the exit surface of the first aspherical lens increases up to a first radius position near the periphery as the radius position increases, and then decreases from the first radius position to the maximum effective radius. The sag of the incident surface of the second aspherical lens monotonically increases as the radius position increases. The sag of the exit surface of the second aspherical lens decreases to the negative side until it reaches a second radius position as the radius position increases, then turns to increase from the second radius position, and shifts from negative to positive at a third radius position larger than the second radius position and increases up to the maximum effective radius. The inspection optical device according to claim 1 or 2.

4. The first radial position is within the range of 70% to 98% of the maximum effective radius of the exit surface of the first aspherical lens, the second radial position is within the range of 30% to 55% of the maximum effective radius of the exit surface of the second aspherical lens, and the third radial position is within the range of 45% to 85% of the maximum effective radius of the exit surface of the second aspherical lens. The optical inspection device according to claim 3.

5. The thickness of the first aspherical lens decreases to a fourth radial position as the radial position increases, then turns to increase from the fourth radial position and increases to the maximum effective radius of the entrance surface. The thickness of the second aspherical lens increases to a fifth radial position as the radial position increases, then turns to decrease from the fifth radial position and decreases to the maximum effective radius of the entrance surface. The optical inspection device according to claim 1 or 2.

6. The fourth radial position is within the range of 35% to 95% of the maximum effective radius of the entrance surface of the first aspherical lens, and the fifth radial position is within the range of 90% or more of the maximum effective radius of the entrance surface of the second aspherical lens. The optical inspection device according to claim 5.

7. The illumination optical system for the optical inspection device according to claim 1.

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