JP2020184562A - Luminaire and inspection apparatus - Google Patents

Abstract

To provide a luminaire and an imaging apparatus that can achieve at least one of an increase in light reception quantity of a camera sensor or a decrease in lighting light quantity drift, and reduction in lighting unevenness.SOLUTION: A luminaire 1 according to the present invention comprises: a plurality of light sources 10 which are linearly arrayed side by side; a cylindrical lens 30 which extends in the array direction of the plurality of light sources 10 to cover the plurality of light sources 10; and a cylindrical lens array 20 which includes a plurality of micro cylindrical lenses 21 arrayed in the array direction between the plurality of light sources 10 and the cylindrical lens 30, wherein the micro cylindrical lenses 21 converge lighting light L10 that the light sources 10 emit in the array direction, and the cylindrical lens 30 converges the lighting light L10 in a direction orthogonal to the array direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lighting device and an inspection device, and for example, relates to a lighting device and an inspection device in macro inspection and spectroscopic imaging inspection of a semiconductor wafer using ultraviolet light.

There are known line-type illuminators and inspection devices using line-type illuminators that condense visible light emitted from LEDs and UV-A light having a wavelength of 360 to 400 nm using a cylindrical lens.

Japanese Unexamined Patent Publication No. 9-45121 Japanese Unexamined Patent Publication No. 2001-127080 Japanese Unexamined Patent Publication No. 2004-354407 Japanese Unexamined Patent Publication No. 2005-077982 JP-A-2007-179823 JP-A-2007-225591 Japanese Unexamined Patent Publication No. 2010-177163 Japanese Unexamined Patent Publication No. 2010-210882 Japanese Unexamined Patent Publication No. 2011-060719 Japanese Unexamined Patent Publication No. 2012-238436 Japanese Unexamined Patent Publication No. 2014-207245 Japanese Unexamined Patent Publication No. 2016-021049

The line-type lighting device and the inspection device using the line-type lighting device have problems such as (1) the amount of light received by the camera sensor, (2) uneven lighting, and (3) drift of the amount of illumination light.

(1) An issue of the amount of light received by the camera sensor is that the amount of light received is not sufficient. Since the UV-B light LED having a center wavelength of 290 nm has low luminous efficiency, when UV-B light is used as the illumination light of the inspection device, the amount of light received by the camera sensor is low and the inspection throughput is lowered.

(2) As an issue of uneven lighting, it is difficult to prepare a diffused plate for eliminating uneven lighting. The LED line lighting reduces uneven lighting by combining it with a diffuser plate. Without a diffuser, uneven lighting occurs due to the LED pitch. However, it is difficult to manufacture a diffuser plate compatible with UV-B light having a central wavelength of 290 nm. In a general diffuser plate, the transmittance of UV-B light is lowered and the light is deteriorated by UV-B light.

(3) The problem of drifting the amount of illumination light is that the amount of illumination light drifts. After the LED is turned on, the temperature of the LED gradually rises, so that the amount of illumination light drifts.

An object of the present invention has been made to solve such a problem, and it is possible to achieve at least one of an increase in the amount of light received by a camera sensor and a reduction in the amount of illumination light drift, and a reduction in illumination unevenness. The purpose is to provide an apparatus and an imaging apparatus.

The lighting device according to the present invention includes a plurality of light sources arranged in a line, a cylindrical lens extending in an arrangement direction of the plurality of light sources so as to cover the plurality of light sources, and the plurality of light sources. A cylindrical lens array including a plurality of microcylindrical lenses arranged in the arrangement direction is provided between the cylindrical lens and the microcylindrical lens, and the microcylindrical lens collects illumination light generated by the light source in the arrangement direction. The cylindrical lens then collects the illumination light in a direction orthogonal to the arrangement direction. With such a configuration, the amount of received light from the illuminated inspection target can be increased.

Further, the inspection device according to the present invention includes the above-described illuminating device, an imaging lens that forms an image of the reflected light reflected by the illuminating device generated by the illuminating device, and the imaging lens. A light receiving sensor for receiving the reflected light is provided. With such a configuration, the amount of received light from the inspection target can be increased.

According to the present invention, it is possible to provide an illuminating device and an imaging device that can achieve at least one of an increase in the amount of light received by the camera sensor and a reduction in the amount of illumination light drift, and a reduction in illumination unevenness.

It is a perspective view which illustrates the structure of the lighting apparatus which concerns on Embodiment 1. FIG. It is a side view which illustrated the structure of the lighting apparatus which concerns on Embodiment 1. FIG. It is sectional drawing which illustrates the structure of the lighting apparatus which concerns on Embodiment 1. FIG. It is a figure which illustrated the inspection apparatus using the lighting apparatus which concerns on Embodiment 1. FIG. It is a perspective view which illustrated the structure of the lighting apparatus which concerns on a comparative example. It is a side view which illustrated the structure of the lighting apparatus which concerns on a comparative example. It is sectional drawing which illustrates the structure of the lighting apparatus which concerns on a comparative example. It is a figure which illustrated the illumination light of the light source in the lighting apparatus which concerns on a comparative example. It is a figure exemplifying the condensing of the illumination light in the arrangement direction by CLA in the illumination apparatus which concerns on Embodiment 1. FIG. FIG. 5 is an enlarged view illustrating the collection of illumination light in the arrangement direction by CLA in the illumination device according to the first embodiment. It is a figure exemplifying the focusing of the illumination light in the direction orthogonal to the arrangement direction by CL in the illumination apparatus which concerns on a comparative example. FIG. 5 is a diagram illustrating the collection of illumination light in a direction orthogonal to the arrangement direction by CL in the illumination device according to the first embodiment. It is a figure which illustrated the state of condensing the illumination light in the direction orthogonal to the arrangement direction by CL in the illumination apparatus which concerns on a comparative example. FIG. 5 is a diagram illustrating a state of condensing illumination light in a direction orthogonal to the arrangement direction by CL in the illumination device according to the first embodiment. It is a graph exemplifying the distribution of the light receiving amount of the light receiving sensor in the lighting apparatus which concerns on a comparative example, the horizontal axis shows the pixel number of a light receiving sensor, and the vertical axis shows the output of a light receiving sensor proportional to the light receiving amount. It is an image which exemplifies the inspection target illuminated by the illumination light in the illumination apparatus which concerns on a comparative example. It is a graph exemplifying the distribution of the light receiving amount of the light receiving sensor in the lighting apparatus which concerns on Embodiment 1, the horizontal axis shows the pixel number of a light receiving sensor, and the vertical axis shows the output of a light receiving sensor proportional to the light receiving amount. It is an image which illustrates the inspection object illuminated by the illumination light in the illumination apparatus which concerns on Embodiment 1. FIG. It is a figure which illustrated the illumination light which illuminates the inspection target in the inspection apparatus which concerns on a comparative example. It is a figure which illustrated the illumination light which illuminates the inspection target in the inspection apparatus which concerns on Embodiment 1. FIG. It is a figure which illustrated the inspection apparatus which concerns on Embodiment 2. In the inspection apparatus according to the second embodiment, it is a graph illustrating the dimming around the visual field, the horizontal axis represents the position of the visual field, and the vertical axis represents the amount of light. It is sectional drawing which illustrates the lighting apparatus which concerns on Embodiment 3. It is a figure which illustrated the lighting apparatus which concerns on Embodiment 4.

Hereinafter, the specific configuration of the present embodiment will be described with reference to the drawings. The following description shows preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. In the following description, those having the same reference numerals indicate substantially the same contents. In addition, some hatching is omitted in order to prevent the drawing from becoming complicated and to clarify the optical path shown in the drawing.

(Embodiment 1)
The lighting device and the inspection device according to the first embodiment will be described. 1 to 3 are views illustrating the configuration of the lighting device according to the first embodiment, FIG. 1 is a perspective view, FIG. 2 is a side view, and FIG. 3 is a sectional view. As shown in FIGS. 1 to 3, the illuminating device 1 includes a plurality of light sources 10, a cylindrical lens array 20 (hereinafter referred to as CLA 20), and a cylindrical lens 30 (hereinafter referred to as CL30). The plurality of light sources 10 are arranged side by side in a line in one direction. In the figure, of the plurality of light sources 10, only some light sources 10 are designated by reference numerals.

Here, for convenience of explanation of the lighting device 1, an XYZ orthogonal coordinate axis system is introduced. The arrangement direction in which the light sources 10 are arranged side by side is defined as the X-axis direction. The direction from the light source 10 toward the cylindrical lens 30 is the Z-axis direction. The direction orthogonal to the X-axis direction and the Z-axis direction is defined as the Y-axis direction.

The plurality of light sources 10 are arranged side by side at a predetermined pitch in the X-axis direction. For example, the plurality of light sources 10 are arranged side by side in a line in the X-axis direction on the substrate 11. Therefore, the arrangement direction of the plurality of light sources 10 is the X-axis direction. The light source 10 is, for example, an LED (Light Emitting Diode). The light source 10 is, for example, a UV-B light LED that emits UV-B light having a center wavelength of 290 nm. The light source 10 is not limited to the UV-B light LED, and may be a UV-A light LED that emits UV-A light having a wavelength of 360 to 400 nm, or an LED that emits visible light. Further, the light source 10 is not limited to the LED, and may be another light source such as a discharge lamp.

The CLA 20 is arranged to face the plurality of light sources 10 so as to cover the plurality of light sources 10. The CLA 20 includes a plurality of cylindrical lenses 21 arranged in the X-axis direction. The cylindrical lens 21 is also called a microcylindrical lens. In the figure, of the plurality of cylindrical lenses 21, only some of the cylindrical lenses 21 are designated by reference numerals. Each cylindrical lens 21 faces each light source 10. Each cylindrical lens 21 extends in the Y-axis direction. The cylindrical axis of the cylindrical portion included in each cylindrical lens extends in the Y-axis direction. The radius of the cylindrical portion included in each cylindrical lens 21 is, for example, 2 to 4 mm.

The cross section of each cylindrical lens 21 orthogonal to the Y-axis direction is U-shaped. Therefore, each cylindrical lens 21 has a curved surface having a U-shaped cross section and a flat bottom surface. The bottom surface of each cylindrical lens 21 faces each light source 10. That is, the bottom surface of each cylindrical lens 21 faces the −Z axis direction. The curved surface of each cylindrical lens 21 faces the + Z axis direction side. The curved surface of each cylindrical lens 21 has a radius of curvature in the X-axis direction. The curved surface of each cylindrical lens 21 does not have a radius of curvature in the Y-axis direction.

Each cylindrical lens 21 faces each light source 10 and collects the illumination light generated by each light source 10 in the X-axis direction. Therefore, each cylindrical lens 21 collects the illumination light in a line extending in the Y-axis direction.

In the present embodiment, the optical axis of each cylindrical lens 21 is arranged so as to pass through the center point of the light emitting surface of each of the opposing light sources 10. The center point of the light emitting surface is, for example, the center point of the light emitting surface in the X-axis direction. The plurality of cylindrical lenses 21 are arranged in the X-axis direction at the same pitch as the plurality of light sources 10 are arranged in the X-axis direction.

The CL 30 extends in the X-axis direction so as to cover the plurality of light sources 10 and the plurality of cylindrical lenses 21. Therefore, the plurality of cylindrical lenses 21 are arranged in the X-axis direction between the plurality of light sources 10 and the CL 30. The cylindrical axis of the cylindrical portion included in the CL 30 extends in the X-axis direction. The radius of the cylindrical portion included in CL30 is, for example, 15 to 30 mm.

The cross section of CL30 orthogonal to the X-axis direction is U-shaped. The CL30 has a curved surface having a U-shaped cross section and a flat bottom surface. The bottom surface of the CL 30 faces the CLA 20 and each light source 10. That is, the bottom surface of the CL30 faces the −Z axis direction. The curved surface of CL30 faces the + Z axis direction side. The curved surface of CL30 has a radius of curvature in the Y-axis direction. The curved surface of CL30 does not have a radius of curvature in the X-axis direction.

The CL30 collects the illumination light generated by each light source 10 in the Y-axis direction. Therefore, the CL30 collects the illumination light in a line extending in the X-axis direction. For example, the optical axis of CL30 is arranged so as to pass through the center point of the light emitting surface of each light source 10. The center point of the light emitting surface is, for example, the center point of the light emitting surface in the Y-axis direction.

FIG. 4 is a diagram illustrating an inspection device using the lighting device according to the first embodiment. As shown in FIG. 4, the inspection device 40 includes a lighting device 1, an imaging lens 41, and a light receiving sensor 42. The inspection device 40 illuminates the inspection target 50 using the above-mentioned lighting device 1. The lighting device 1 in the inspection device 40 emits the illumination light L10 to the inspection target 50. The imaging lens 41 forms an image of the reflected light R10 reflected by the inspection target 50 by the illumination light L10 generated by the illumination device 1. The light receiving sensor 42 receives the reflected light R10 imaged by the imaging lens 41. In this way, the inspection device 40 inspects the inspection target 50 by receiving the reflected light R10 from the inspection target 50 illuminated by the illumination light L10. The inspection target 50 is, for example, a wafer.

Next, in order to compare with the lighting device 1 according to the first embodiment, the lighting device according to the comparative example will be described. 5 to 7 are views illustrating the configuration of the lighting device according to the comparative example, FIG. 5 is a perspective view, FIG. 6 is a side view, and FIG. 7 is a cross-sectional view. As shown in FIGS. 5 to 7, the illuminating device 101 of the comparative example includes a plurality of light sources 110 and a cylindrical lens 130 (hereinafter, referred to as CL 130). The plurality of light sources 110 arranged on the substrate 11 have the same configuration as the plurality of light sources 10 of the first embodiment. The lighting device 101 of the comparative example does not include the CLA 20.

Also in the comparative example, the XYZ orthogonal coordinate axis system is introduced for convenience of explanation. The direction in which the light sources 110 are arranged is defined as the X-axis direction. The direction from the light source 110 to the CL 130 is the Z-axis direction. The direction orthogonal to the X-axis direction and the Z-axis direction is defined as the Y-axis direction.

CL130 extends in the X-axis direction. The cross section of CL130 orthogonal to the X-axis direction is U-shaped. The CL 130 has a curved surface having a U-shaped cross section and a flat bottom surface. The bottom surface of the CL 130 faces each light source 110. That is, the bottom surface of the CL 130 faces the −Z axis direction. The curved surface of CL130 faces the + Z axis direction side. The CL 130 collects the illumination light generated by each light source 110 in the Y-axis direction. Therefore, the CL 130 collects the illumination light in a line extending in the X-axis direction. The optical axis of CL 130 is arranged so as to pass through the center of each light source 110.

Next, the operation of the illumination device 1 of the present embodiment is as follows: <concentration of illumination light in the arrangement direction by CLA and increase in the amount of received light>, <concentration of illumination light in a direction orthogonal to the arrangement direction by CL>. , <Reduction of lighting unevenness> will be described separately.

<Condensing illumination light in the arrangement direction by CLA and increasing the amount of received light>
FIG. 8 is a diagram illustrating the illumination light of the light source in the illumination device according to the comparative example. FIG. 9 is a diagram illustrating the collection of illumination light in the arrangement direction by the CLA in the illumination device according to the first embodiment. FIG. 10 is an enlarged view illustrating the collection of illumination light in the arrangement direction by the CLA in the illumination device according to the first embodiment.

As shown in FIG. 8, in the lighting device 101 of the comparative example, the illumination light L110 generated from the light source 110 passes through the CL 130 and illuminates the inspection target 50. The CL 130 does not collect the illumination light L110 in the arrangement direction of the light sources 110, that is, in the X-axis direction. When viewed from the Y-axis direction, the illumination light L110 illuminates the wafer of the inspection target 50 without being affected by the CL130. Therefore, of the reflected light R110 reflected by the inspection target 50, the reflected light R110a deviating from the NA of the imaging lens 41 does not reach the light receiving sensor 42. Therefore, the light receiving sensor 42 causes a loss in the amount of received light received, and the amount of received light cannot be increased.

On the other hand, as shown in FIG. 9, in the illumination device 1 of the present embodiment, the illumination light L10 generated from the light source 10 passes through the CLA 20 and CL 30 and illuminates the inspection target 50. The CLA 20 collects the illumination light L10 in the arrangement direction of the light sources 10, that is, in the X-axis direction.

As shown in FIG. 10, for example, the light source 10 is arranged at the position of the focal length of the cylindrical lens 21 so that the light emitted from the center point C of the light source 10 becomes parallel light. In reality, the light emitting surface of the light source 10 is not a point light source, so it expands as shown in the figure.

As shown in FIG. 9, CL30 does not collect the illumination light L10 in the X-axis direction, as in the comparative example. When viewed from the Y-axis direction, the illumination light L10 is focused by the CLA 20 and illuminates the wafer of the inspection target 50 without being affected by the CL 30.

In the illumination device 1 of the present embodiment, the CLA 20 is arranged so that the illumination light L10 generated from the light source 10 enters the NA of the imaging lens 41. Then, the illumination light L10 is focused by the CLA 20 so as to enter the NA of the imaging lens 41. Therefore, among the reflected light R10 reflected by the inspection target 50, the reflected light R10 deviating from the NA of the imaging lens 41 can be reduced. As a result, the light receiving sensor 42 can increase the amount of received light received.

In FIGS. 8 and 9, only eight light sources 10 and 110 are shown, but as shown in FIGS. 1 and 5, in the comparative example and the present embodiment, the light sources 10 are installed along the X axis. The range is long enough. Therefore, although there are differences between CL130 and CL30, the illuminance of the irradiated surface on the inspection target 50 such as a wafer is basically the same regardless of the presence or absence of CLA20. However, in the present embodiment, the loss of the reflected light R10 received by the light receiving sensor 42 is reduced by condensing the light sources 10 in the arrangement direction by the CLA 20. As a result, the amount of received light can be increased.

<Condensing illumination light in a direction orthogonal to the arrangement direction by CL>
Next, the condensing of illumination light in a direction orthogonal to the arrangement direction by CL130 and CL30 will be described. FIG. 11 is a diagram illustrating the collection of illumination light in a direction orthogonal to the arrangement direction by CL in the illumination device according to the comparative example. FIG. 12 is a diagram illustrating the collection of illumination light in a direction orthogonal to the arrangement direction by CL in the illumination device according to the first embodiment. FIG. 13 is a diagram illustrating a state of condensing illumination light in a direction orthogonal to the arrangement direction by CL in the illumination device according to the comparative example. FIG. 14 is a diagram illustrating a state in which illumination light is collected in a direction orthogonal to the arrangement direction by CL in the illumination device according to the first embodiment.

As shown in FIGS. 11 and 13, in the lighting device 101 of the comparative example, the illumination light L110 generated from the light source 110 passes through the CL 130 and illuminates the inspection target 50. The CL 130 collects the illumination light L110 in a direction orthogonal to the arrangement direction of the light sources 10, that is, in the Y-axis direction.

As shown in FIGS. 12 and 14, in the illumination device 1 of the present embodiment, the illumination light L10 generated from the light source 10 passes through the CLA 20 and CL 30 and illuminates the inspection target 50. The CLA 20 does not collect the illumination light L10 in the Y-axis direction orthogonal to the arrangement direction of the light sources 10. The CL30 collects the illumination light L10 in the Y-axis direction orthogonal to the arrangement direction of the light sources 10.

As shown in FIGS. 11 and 12, the design is such that the illumination light L10 is focused to illuminate the inspection target 50, which is the same as in the comparative example and the first embodiment. However, in the lighting device 1 of the present embodiment, the size of CL30 is increased and the focal length of CL30 is set longer than that of CL130 of the comparative example. For example, the radius of the cylindrical portion included in the CL 130 of the comparative example is 10 mm, whereas the radius of the cylindrical portion included in the CL 30 of the present embodiment is 15 to 30 mm. Therefore, in the CL30 of the present embodiment, the density of the illumination light L10 is increased by reducing the magnification of the image of the light emitting surface of the light source 10 projected on the inspection target 50.

As described above, in the present embodiment, the illumination light L10 is focused in the direction orthogonal to the arrangement direction of the light sources 10 and the arrangement direction of the light sources 10. In the arrangement direction of the light sources 10, the CLA 20 collects the illumination light L10 so as to enter the NA of the imaging lens 41. The amount of illumination light L10 is increased by using CL30 having a large focal length in a direction orthogonal to the arrangement direction of the light sources 10. By condensing in both directions in this way, the amount of received light can be increased.

<Reduction of uneven lighting>
Next, reduction of lighting unevenness will be described. FIG. 15 is a graph illustrating the distribution of the light receiving amount of the light receiving sensor in the lighting device according to the comparative example, the horizontal axis shows the pixel number of the light receiving sensor, and the vertical axis shows the output of the light receiving sensor proportional to the light receiving amount. Shown. FIG. 16 is an image illustrating an inspection target illuminated by the illumination light in the illumination device according to the comparative example. FIG. 17 is a graph illustrating the distribution of the light receiving amount of the light receiving sensor in the lighting device according to the first embodiment, the horizontal axis represents the pixel number of the light receiving sensor, and the vertical axis represents the output of the light receiving sensor proportional to the light receiving amount. Is shown. FIG. 18 is an image illustrating an inspection target illuminated by the illumination light in the illumination device according to the first embodiment.

As shown in FIGS. 15 and 16, lighting unevenness occurs in the lighting device 101 of the comparative example. In the lighting device 101 of the comparative example, since the light sources 110 are arranged at intervals, the amount of light of the illumination light L110 increases or decreases along the arrangement direction of the light sources 110.

On the other hand, as shown in FIGS. 17 and 18, in the lighting device 1 of the present embodiment, uneven lighting does not occur. In the illuminating device 1 of the embodiment, the light sources 10 are arranged at intervals as in the comparative example, but are in a state equivalent to having a continuous light emitting surface by the CLA 20.

FIG. 19 is a diagram illustrating illumination light for illuminating an inspection target in the inspection device according to the comparative example. FIG. 20 is a diagram illustrating illumination light for illuminating an inspection target in the inspection device according to the first embodiment.

As shown in FIG. 19, in the lighting device 101 of the comparative example, the light sources 110 are arranged at intervals. Then, the number of light emitting surfaces of the light source 110 that emits the illumination light L 110 incident on the NA of the imaging lens 41 differs depending on the position on the inspection target 50. For example, at a certain position, the reflected light R110 by the illumination light L110 from the light emitting surfaces of the four light sources 110 is incident on the imaging lens 41. Further, at other positions, the reflected light R110 by the illumination light L110 from the light emitting surfaces of the five light sources 110 is incident on the imaging lens 41. As described above, in the inspection device 140 of the comparative example, the number of light emitting surfaces entering the imaging lens 41 differs depending on the position on the inspection target 50, so that uneven illumination occurs.

On the other hand, as shown in FIG. 20, in the lighting device 1 of the present embodiment, the light sources 10 are arranged at intervals at intervals, but the CLA 20 makes it equivalent to having a continuous light emitting surface. There is. Therefore, the amount of reflected light R10 entering the NA of the imaging lens 41 is equal regardless of the position on the inspection target 50. Therefore, in the inspection device 40, it is possible to reduce the illumination unevenness caused by the arrangement pitch of the light source 10.

As described above, in the present embodiment, the illumination unevenness can be reduced by the continuous light emitting surface by the CLA 20. Therefore, the diffuser plate used in the lighting device 101 of the comparative example can be eliminated. As a result, the amount of received light can be further increased.

For example, when the amount of light without the diffuser is 1, the efficiency of the diffuser is 0.5. Then, in the inspection device 140 of the comparative example, the amount of light received by the light receiving sensor 42 becomes 0.5 by using the diffuser plate. On the other hand, in the lighting device 1 of the present embodiment, the diffuser plate can be eliminated. Therefore, the inspection device 40 of the present embodiment can double the amount of light received by the light receiving sensor 42 as compared with the inspection device 140 of the comparative example.

Next, the effect of this embodiment will be described. By combining the CLA 20 and the CL 30, the lighting device 1 of the present embodiment can independently collect light in the directions orthogonal to the arrangement direction of the light sources 10 and the arrangement direction of the light sources 10. Then, the amount of light received by the light receiving sensor 42 can be increased by matching the focusing in the array direction with the NA of the imaging lens 41. For example, in an experiment, it can be increased 6 times as compared with a comparative example.

Further, the lighting device 1 of the present embodiment includes a CLA 20. By setting the CLA 20 to a state equivalent to having a continuous light emitting surface, it is possible to reduce the illumination unevenness caused by the arrangement pitch of the light source 10.

Further, since the lighting device 1 of the present embodiment can reduce lighting unevenness, it is possible to eliminate the need for a diffuser plate. By multiplying the above 6 times, it is possible to obtain 12 times the amount of received light as compared with the lighting device 101 of the comparative example.

Further, by increasing the amount of received light, the throughput of the inspection of the inspection target 50 can be improved.

(Embodiment 2)
Next, the lighting device according to the second embodiment will be described. The lighting device of the second embodiment relates to measures for dimming around the visual field. FIG. 21 is a diagram illustrating an inspection device according to the second embodiment. FIG. 22 is a graph illustrating dimming around the visual field in the lighting device according to the second embodiment, the horizontal axis represents the position of the visual field, and the vertical axis represents the amount of light. FIG. 21 shows an enlarged view of the vicinity of the light source 10 of the lighting device.

As shown in FIG. 21, in the illumination device 1a of the present embodiment, the pitch of the light source 10 at the visual field end in the arrangement direction and the pitch of each cylindrical lens 21 at the visual field end are shifted. For example, the reference light source 10 is the central light source 13. The optical axis of the cylindrical lens 21 facing the central light source 13 passes through the central point of the light emitting surface of the central light source 13. The plurality of light sources 10 include a central light source 13, a light source 14 arranged on the + X-axis direction side of the central light source 13, and a light source 15 arranged on the −X-axis direction side of the central light source 13.

When the + X-axis direction side in the X-axis direction is one side and the −X-axis direction side is the other side, the light source 14 arranged on the + X-axis direction side is called a one-side light source 14. The light source 15 arranged on the −X axis direction side is called the other side light source 15. The central light source 13 is arranged between the one-side light source 14 and the other-side light source 15.

The optical axis of the cylindrical lens 21 facing the one-sided light source 14 passes through the −X-axis direction side from the center point of the light emitting surface of the one-sided light source 14. The optical axis of the cylindrical lens 21 facing the other side light source 15 passes through the + X axis direction side from the center point of the light emitting surface of the other side light source 15.

As shown in FIG. 21, the illumination light L10 that illuminates the inspection target 50 from the light source 10 via the CLA 20 and CL30 and the reflected light R10 that the illumination light L10 is reflected by the inspection target 50 and incident on the imaging lens 41. Set the connected optical path. In the present embodiment, the principal point of the cylindrical lens 21 facing the central light source 13 is arranged on the optical axis connecting the principal point of the imaging lens 41 and the central point of the light emitting surface of the central light source 13. The imaging lens 41 forms an image of the reflected light R10 reflected by the inspection target 50 by the illumination light L10 generated from the central light source 13.

As shown in the enlarged view of FIG. 21, the principal point of the cylindrical lens 21 facing the one-sided light source 14 is an optical axis connecting the principal point of the imaging lens 41 and the center point of the light emitting surface of the one-sided light source 14. It is placed on top. The imaging lens 41 forms an image of the reflected light R10 reflected by the inspection target 50 by the illumination light L10 generated from the one-side light source 14.

Although not shown, the principal point of the cylindrical lens 21 facing the other side light source 15 is arranged on the optical axis connecting the principal point of the imaging lens 41 and the center point of the light emitting surface of the other side light source 15. ing. The imaging lens 41 forms an image of the reflected light R10 reflected by the inspection target 50 by the illumination light L10 generated from the other side light source 15.

Specifically, for example, as shown in FIG. 21, in the inspection device 40a, the length of the visual field illumination composed of a plurality of light sources 10 arranged in the X-axis direction is mm. The length between the light emitting surface of the light source 10 and the inspection target 50 is 300 mm. The length between the inspection target 50 and the principal point of the imaging lens 41 is 300 mm. The length between the image forming lens 41 and the image formed by the light receiving sensor 42 is 300 mm. The illumination field of view in the X-axis direction is 150 mm. The field of view of the inspection target 50 in the X-axis direction is 75 mm.

As shown in the enlarged view of FIG. 21, the pitch of the light source 10 in the X-axis direction is 4 mm. The length between the light emitting surface of the light source 10 and the principal point of the cylindrical lens 21 facing the light source 10 is 4 mm.

In this case, the deviation in the X-axis direction between the center point of the light emitting surface of the light source 10 at the field edge and the principal point of the cylindrical lens 21 corresponding to the light source 10 is 0.2 mm. The pitch between the cylindrical lens 21 and the adjacent cylindrical lens 21 is 3.99 mm. Therefore, at the field edge, the pitch of the cylindrical lens 21 is 0.01 mm, 0.3% less than the pitch of the light source 10.

In FIG. 21, one side light source 14 is illustrated as the light source 10 at the visual field end on the + X axis direction, but the arrangement relationship between the light source 10 at the visual field end on the −X axis direction and the cylindrical lens 21 is also in the + X axis direction. -The same applies except that the X-axis direction is different.

In this way, by shifting the pitch of the light source 10 at the field edge in the arrangement direction and the pitch of each cylindrical lens 21 of the CLA 20 at the field edge, dimming around the field of view can be suppressed.

As shown in FIG. 22, in the case of the first embodiment, the amount of light around the visual field is reduced. In the first embodiment, the pitch of the light source 10 and the pitch of the cylindrical lens 21 are both 4 mm. In the present embodiment, for example, the pitch of the light source 10 remains 4 mm, and the pitch of the cylindrical lens 21 around the field of view is shifted by 0.01 mm, 0.02 mm, and 0.04 mm from 4 mm. That is, the pitch of the cylindrical lens 21 around the field of view is set to 3.99 mm, 3.98 mm, and 3.96 mm. When the pitch of the cylindrical lens 21 around the visual field is changed from 4 mm to 3.99 mm and 3.98 mm, the decrease in the amount of light around the visual field can be suppressed. Further, in this case, although not shown, the decrease in the amount of light around the visual field can be suppressed as compared with the comparative example.

According to the lighting device 1a and the inspection device 40a of the present embodiment, it is possible to suppress the amount of light around the visual field of the light receiving sensor 42 from dimming with respect to the amount of light in the center of the visual field. Other configurations and effects are included in the description of Embodiment 1.

(Embodiment 3)
Next, the third embodiment will be described. The lighting device of this embodiment is an example of a flow path structure of a fluid for cooling. FIG. 23 is a cross-sectional view illustrating the lighting device according to the third embodiment. FIG. 23 shows an enlarged view of a part of the lighting device.

As shown in FIG. 23, the lighting device 1b includes a housing 12. The housing 12 has a cavity inside. The surface of the substrate 11 opposite to the surface on which the light source 10 is arranged is attached to the inner surface of the cavity. Therefore, the light source 10 faces the cavity side. The CLA 20 is arranged at a distance from the substrate 11 on which the plurality of light sources 10 are arranged. A space is formed between the light source 10 and the CLA 20.

In the present embodiment, the fluid 16 for cooling the light source 10 flows between the light source 10 and the CLA 20. The fluid 16 that cools the light source 10 is, for example, nitrogen gas. The fluid 16 is not limited to nitrogen gas, but may be CDA (Clean Dry Air), or any other gas or liquid as long as the light source 10 is cooled. Further, in order to balance the pressure of the fluid 16 flowing between the light source 10 and the CLA 20, a fluid may also flow between the CLA 20 and the CL 30 (not shown).

Generally, the temperature of the light source 10 gradually rises after being turned on. This causes a light amount drift. In order to reduce this, it is necessary to flow nitrogen gas or CDA around the light source 10 to exhaust heat. In the lighting device of the comparative example, the space between the light source 110 and the CL 130 is wide. Therefore, even if a fluid such as nitrogen gas is allowed to flow between the light source 110 and the CL 130, the fluid does not easily flow around the light source 10.

According to the lighting device of the present embodiment, by using the CLA 20 as a partition wall, a narrow flow path in contact with the light source 10 can be formed. Therefore, the fluid 16 can be efficiently flowed around the light source 10 to be cooled. Other configurations and effects are included in the description of embodiments 1 and 2.

(Embodiment 4)
Next, the lighting device according to the fourth embodiment will be described. In the lighting device of this embodiment, the light source can be switched. FIG. 24 is a diagram illustrating the lighting device according to the fourth embodiment. As shown in FIG. 24, the lighting device 1c has a plurality of light sources 10a on the substrate 11. The plurality of light sources 10a are arranged side by side at intervals in the X-axis direction. The plurality of light sources 10a face each cylindrical lens 21.

Further, the lighting device 1c further includes a plurality of light sources 10b on the substrate 11. The light source 10b has a different wavelength of light generated from the light source 10a. Each light source 10b is arranged between adjacent light sources 10a. Therefore, the light sources 10a and the light sources 10b are alternately arranged on the substrate 11 in the X-axis direction.

When the illumination light L10 generated from the light source 10b is used, the substrate 11 or the CLA 20 is moved in the X-axis direction by a half pitch of the light source 10a or a half pitch of the light source 10b. As a result, each cylindrical lens 21 can be made to face a plurality of light sources 10b. In this way, the illumination light L10 can be switched so as to be generated from the light source 10a or the light source 10b.

In the lighting device 1c of the present embodiment, two types of light sources 10a and 10b are alternately mounted on the substrate 11. Then, if the substrate 11 or CLA 20 is moved by the pitch in the arrangement direction of the light sources 10a and 10b, the two types of light sources 10a and 10b can be switched without moving the optical axis of the illumination light L10. In this case, there is no loss in the amount of received light. Further, since the light sources 10b are arranged between the adjacent light sources 10a, the increase in size can be suppressed.

Although the embodiments of the present invention have been described above, the present invention includes appropriate modifications that do not impair its purpose and advantages, and is not limited by the above embodiments.

1, 1a, 1b, 1c Lighting device 10, 10a, 10b Light source 11 Board 12 Housing 13 Central light source 14 One side light source 15 Other side light source 16 Fluid 20 Cylindrical lens array 21 Cylindrical lens 30 Cylindrical lens 40, 40a Inspection device 41 connection Image lens 42 Light receiving sensor 50 Inspection target 101 Lighting device 110 Light source 130 Cylindrical lens C Center point L10, L110 Illumination light R10, R110, R110a Reflected light

Claims (10)

Multiple light sources arranged in a line and
A cylindrical lens extending in the arrangement direction of the plurality of light sources so as to cover the plurality of light sources.
A cylindrical lens array including a plurality of microcylindrical lenses arranged in the arrangement direction between the plurality of light sources and the cylindrical lens.
With
The microcylindrical lens collects the illumination light generated by the light source in the arrangement direction.
The cylindrical lens collects the illumination light in a direction orthogonal to the arrangement direction.
Lighting device. The cylindrical axis of the cylindrical portion included in the cylindrical lens extends in the arrangement direction.
The cylindrical axis of the cylindrical portion included in the microcylindrical lens extends in the orthogonal direction.
The lighting device according to claim 1. The radius of the cylindrical portion included in the cylindrical lens is 15 to 30 mm, and the radius of the cylindrical portion included in the microcylindrical lens is 2 to 4 mm.
The lighting device according to claim 1 or 2. The plurality of microcylindrical lenses were arranged in the arrangement direction at the same pitch as the pitch in which the plurality of light sources were arranged in the arrangement direction.
The lighting device according to any one of claims 1 to 3. The plurality of light sources are arranged on the one side and the other side when one direction side in the arrangement direction is one side and the opposite direction of the one side is the other side. The other side light source and the central light source arranged between the one side light source and the other side light source are included.
The optical axis of the microcylindrical lens facing the central light source passes through the central point of the light emitting surface of the central light source.
The optical axis of the microcylindrical lens facing the one-sided light source passes through the other side of the center point of the light emitting surface of the one-sided light source.
The optical axis of the microcylindrical lens facing the other side light source passes through the one side of the center point of the light emitting surface of the other side light source.
The lighting device according to any one of claims 1 to 4. A fluid that cools the light source flows between the light source and the cylindrical lens array.
The lighting device according to any one of claims 1 to 5. The plurality of light sources are a plurality of first light sources.
A plurality of second light sources having different wavelengths of light generated from the first light source are further provided.
Each of the second light sources is arranged between adjacent first light sources.
By moving the substrate in which the first light source and the second light source are alternately arranged in the arrangement direction or the cylindrical lens array in the arrangement direction, the illumination light is emitted from the first light source or the second light source. Switchable to be generated,
The lighting device according to any one of claims 1 to 6. The lighting device according to any one of claims 1 to 7.
An imaging lens that forms an image of the reflected light reflected by the illumination target generated by the illumination device.
A light receiving sensor that receives the reflected light imaged by the imaging lens, and
Inspection device equipped with. The illumination light generated from the light source was focused by the microcylindrical lens so as to enter the NA of the imaging lens.
The inspection device according to claim 8. The plurality of light sources are arranged on the one side and the other side when one direction side in the arrangement direction is one side and the opposite direction of the one side is the other side. The other side light source and the central light source arranged between the one side light source and the other side light source are included.
The principal points of the microcylindrical lens facing the central light source are the principal point of the imaging lens that forms an image of the reflected light reflected by the illumination light generated from the central light source and the center. Arranged on the optical axis connecting the center point of the light emitting surface of the light source,
The principal point of the microcylindrical lens facing the one-sided light source is arranged on an optical axis connecting the principal point of the imaging lens and the center point of the light emitting surface of the one-sided light source.
The principal point of the microcylindrical lens facing the other side light source is arranged on an optical axis connecting the principal point of the imaging lens and the center point of the light emitting surface of the other side light source.
The inspection device according to claim 8 or 9.