2. Visual perception methods

Abstract

To provide a two-field recognition means that is small and lightweight and yet can clearly acquire images of two fields of view. [Solution] A two-field recognition means is provided, which is positioned between the first surface and the second surface in a state where the first surface and the second surface are facing each other in parallel, and which is capable of acquiring a first image on the first surface side and a second image on the second surface side, and which comprises a first optical path for guiding the first image, a second optical path for guiding the second image, a third optical path perpendicular to the first optical path and the second optical path, an optical element for guiding the first image and the second image superimposed on the third optical path, an imaging means for capturing the first image and the second image guided to the third optical path, and illumination that provides coaxial light parallel to the first optical path and illuminating the first surface or coaxial light parallel to the second optical path and illuminating the second surface.

Description

[Technical Field]

[0001] The present invention relates to a two-view recognition means used for alignment when mounting chip components on a substrate. [Background technology]

[0002] When mounting chip components such as semiconductor chips on a substrate, alignment is performed using alignment marks provided on the chip component and the substrate. The alignment marks on both the chip component and the substrate are provided on the electrode side at fixed positions relative to the electrode arrangement. Therefore, by acquiring positional information on the alignment marks on the chip component and the substrate, the relative positional relationship between the chip component and the substrate can be grasped and position adjustment can be performed.

[0003] It is well known that there are two methods for mounting chip components on a substrate: face-up mounting, in which the electrode surface of the chip component faces the electrode surface of the substrate, and face-down mounting, in which the electrode surface of the chip component faces the electrode surface of the substrate. In face-up mounting, both electrode surfaces face the same direction, so the alignment marks of the chip component and the substrate can be captured within a single field of view. In contrast, face-down mounting typically uses a two-view recognition device 100, as shown in Figure 8, which captures the alignment mark AC of the chip component C in one field of view and the alignment mark AS of the substrate S in the other field of view.

[0004] Here, the two-field-of-view recognition means 100 shown in Figure 8 has the function of acquiring images of two opposing fields of view, upper and lower, but is often configured to use a separate imaging means for each field of view. An example is shown in Figure 9, where, as shown in Figure 9(a), the image of the upper field of view is acquired by imaging means 204 after changing the optical path at mirror surface 30A, and the image of the lower field of view is acquired by imaging means 205 after changing the optical path at mirror surface 30B. In addition, many configurations involve changing the optical path as shown in Figure 9(b) to align the orientations of both imaging means. With the configuration shown in Figure 9, although there is slight light absorption by optical elements on the way to both imaging means, there is little attenuation of the light intensity when acquiring images.

[0005] On the other hand, with the increasing demand for shorter mounting takt time, it is necessary to operate the dual-field recognition means 100 at high speed between the position shown in Fig. 8 and the retracted position, and it is also necessary to converge vibrations in a short time immediately after moving to the position shown in Fig. 8. For this reason, there is a strong demand for dual-field recognition means to be smaller and lighter, and from this perspective, there is also a lot of interest in dual-field recognition means that acquire images of two fields of view with one imaging means (for example, Patent Document 1).

[0006] Fig. 10 shows an example of a two-field-of-view recognition means 110 in which one imaging means acquires images of two fields of view. Here, Fig. 10(a) shows the basic configuration of the two-field-of-view recognition means 110, in which an optical element 3 superimposes images of the two fields of view and captures them with the imaging means 2. The optical element 3 is composed of a half mirror 31 and a mirror 32, and since there is only one imaging means, as shown in the top view in Fig. 10(b), it is possible to make the optical element smaller and lighter than the one having two imaging means shown in Fig. 9(b). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. WO2024 / 014077 Summary of the Invention [Problem to be solved by the invention]

[0008] 10, an upper field of view image of the optical path indicated by the dashed-dotted line is reflected by surface 31B of half mirror 31 toward mirror 32, reflected by mirror surface 32M of mirror 32, transmitted through half mirror 31, and captured by imaging means 2. In addition, a lower field of view image of the optical path indicated by the dashed-two-dotted line is reflected by surface 31A of half mirror 31 and captured by imaging means 2.

[0009] Incidentally, even if half mirror 31 and mirror 32 do not attenuate light, half mirror 31 reflects 50% of the incident light and transmits 50%, and mirror surface 32M of mirror 32 reflects 100% of the incident light, the amount of light in the upper field of view image will be reduced to 25% when it reaches imaging means 2, and the amount of light in the lower field of view image will be reduced to 50% when it reaches imaging means 2. As a result, the depth of focus will be shallow, making it difficult to obtain a clear alignment mark image.

[0010] Furthermore, even if the optical element 3 shown in FIG. 10(a) is replaced with the dichroic prism 300 shown in FIG. 11, the imaging means 2 can acquire an upper field of view image and a lower field of view image in a superimposed manner. However, since the upper field of view image and the lower field of view image are acquired in different light wavelength ranges, the reduction in the amount of light acquired by the imaging means 2 cannot be avoided as with the optical element 3 configured as shown in FIG. 10(a).

[0011] Therefore, it is sufficient to provide lighting to brighten the range to be imaged in the upper and lower fields of view. For this purpose, we considered using oblique lighting, but with oblique lighting, it is necessary to irradiate light from all around to avoid creating shadows, and we found that this would be too large to place in the space between chip component C and the two-field of view recognition means, and in the space between the two-field of view recognition means and board S, as shown in Figure 8.

[0012] 12, Patent Document 1 introduces a method in which a half mirror 21 is provided in the optical path from the optical element 3 to the imaging means 2, and light emitted from the light source 20 is reflected by a surface 21A toward the optical element 3, and coaxial light is irradiated onto the upper and lower fields of view via the optical element 3. With this method, it is possible to irradiate light onto the chip component C and the board S in the state shown in FIG. 8 without providing an additional light source between the chip component C and the board S.

[0013] However, of the light emitted from light source 20 and reflected by surface 21A, the light reflected by surface 31A of half mirror 31 is irradiated onto the lower field of view, while the light transmitted through half mirror 31, reflected by mirror surface 32M of mirror 32, and then reflected by surface 31B of half mirror 31 is irradiated onto the upper field of view, resulting in the same light intensity distribution as when capturing an image. That is, assuming that light is not attenuated by half mirror 31 and mirror 32, half mirror 31 reflects 50% of the incident light and transmits 50%, and mirror surface 32M of mirror 32 reflects 100% of the incident light, the amount of light irradiated onto the upper field of view is 50% of that on the lower field of view. Therefore, when the conditions for the upper and lower fields of view are the same, in the method shown in FIG. 12, the amount of light in the image for the upper field of view is 25% of that for the lower field of view, resulting in a large difference in clarity in the images superimposed by imaging means 2.

[0014] The present invention has been made in view of the above problems, and provides a two-field recognition means that is small and lightweight yet capable of clearly acquiring images from two fields of view. [Means for solving the problem]

[0015] To solve the above problems, the invention described in claim 1 is: A two-view recognition means that is disposed between a first surface and a second surface in a state where the first surface and the second surface are opposed to each other in parallel, and is capable of acquiring a first image on the first surface side and a second image on the second surface side, The two-view recognition means includes a first optical path that guides the first image, a second optical path that guides the second image, a third optical path that is perpendicular to the first optical path and the second optical path, an optical element that guides the first image and the second image onto the third optical path while superimposing them, an imaging means that images the first image and the second image guided onto the third optical path, and illumination that provides coaxial light that is parallel to the first optical path and irradiates the first surface, or coaxial light that is parallel to the second optical path and irradiates the second surface.

[0016] The invention described in claim 2 is a two-field recognition means described in claim 1, The illumination is a two-view recognition means that is arranged in the first optical path and irradiates the first surface with coaxial light parallel to the first optical path, or that is arranged in the second optical path and irradiates the second surface with coaxial light parallel to the second optical path.

[0017] The invention described in claim 3 is the two-view recognition means described in claim 2, The illumination is a two-field recognition means configured by a first illumination arranged in the first optical path and irradiating the first surface with coaxial light parallel to the first optical path, and a second illumination arranged in the second optical path and irradiating the second surface with coaxial light parallel to the second optical path.

[0018] The invention described in claim 4 is a two-view recognition means according to any one of claims 1 to 3, the optical element includes a half mirror and a mirror, This is a two-field recognition means that guides the portion of light incident from either the first or second optical path, reflected by the half-mirror, to the third optical path, and the portion of light incident from the other optical path, transmitted by the half-mirror, is reflected by the mirror, and the portion of the light transmitted by the half-mirror is guided to the third optical path.

[0019] The invention described in claim 5 is a two-view recognition means according to any one of claims 1 to 3, the optical element is a dichroic prism, The first color, which is the color of the light emitted by the first lighting, is different from the second color, which is the color of the light emitted by the second lighting, The dichroic prism is a two-view recognition means having a first reflecting surface that reflects the first image of the first color to the third optical path and a second reflecting surface that reflects the second image of the second color to the third optical path.

[0020] The invention described in claim 6 is the two-view recognition means described in claim 3, When acquiring the first image, only the first illumination is turned on; The two-view recognition means turns on only the second illumination when acquiring the second image. [Effects of the Invention]

[0021] The two-view recognition means of the present invention is small and lightweight, yet can clearly capture images from two fields of view. This allows for high-speed, high-precision alignment in mounting work, etc., thereby reducing takt time. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a diagram showing the configuration of a two-viewpoint recognition means according to the embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating a first optical path, a second optical path, and a third optical path in the embodiment of the present invention. [Figure 3] 1A is a diagram showing a state in which parallel coaxial light is irradiated onto a first optical path, and FIG. 1B is a diagram showing a state in which parallel coaxial light is irradiated onto a second optical path, in an embodiment of the present invention. [Figure 4] FIG. 10 is a diagram showing the configuration of a two-viewpoint recognition means according to a first modified example of an embodiment of the present invention. [Figure 5] FIG. 10A is a diagram showing a state in which parallel coaxial light is irradiated onto the first optical path, and FIG. 10B is a diagram showing a state in which parallel coaxial light is irradiated onto the second optical path, in a first variant of an embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing the configuration of a two-viewpoint recognition means according to a second modified example of the embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing the configuration of a two-viewpoint recognition means according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing the state in which a two-view recognition means is used when aligning a chip component with a substrate. [Figure 9] This is an example of a two-viewpoint recognition means equipped with two imaging means, where (a) shows a configuration equipped with imaging means corresponding to upper and lower optical paths, and (b) shows the optical paths for the two imaging means to face in the same direction. [Figure 10]This is an example in which one imaging means acquires images of two fields of view, where (a) shows a configuration in which both upper and lower optical paths are guided to the imaging means, and (b) shows the effect of reducing the number of parts by using one imaging means. [Figure 11] FIG. 10 is a diagram showing an example in which a dichroic prism is used to allow one imaging means to acquire images of two fields of view. [Figure 12] FIG. 10 is a diagram showing a two-view recognition means provided with a light source for compensating for a decrease in light intensity caused by using two optical paths to guide to one imaging means. DETAILED DESCRIPTION OF THE INVENTION

[0023] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram for explaining the configuration of a two-viewpoint recognition means 1 in an embodiment of the present invention.

[0024] The two-viewpoint recognition means 1 includes, as its components, an imaging means 2, an optical element 3 having a half mirror 31 and a mirror 32, a first illuminator 4 having a light source 40 and a half mirror 41, and a second illuminator 5 having a light source 50 and a half mirror 51. Similarly to the two-viewpoint recognition means 100 shown in Fig. 8, the two-viewpoint recognition means 1 in Fig. 1 acquires a first image on the upper surface (first surface) side in the Z direction and a second image on the lower surface (second surface) side in the Z direction.

[0025] Furthermore, the two-view recognition means 1 in Figure 1, like the two-view recognition means 100 shown in Figure 8, acquires a first image on the upper surface (first surface) in the Z direction and a second image on the lower surface (second surface) in the Z direction by superimposing them on each other.

[0026] The imaging means 2 has a function of acquiring a two-dimensional image and outputting the image as digital data.

[0027] 2, the optical element 3 superimposes a first image that has passed through the first optical path OP1 and a second image that has passed through the second optical path OP2, and guides the superimposed images to the imaging means 2 via a third optical path OP3 that is perpendicular to the respective optical paths. A portion of the first image that has passed through the first optical path OP1 passes through the half mirror 41 (without changing direction), a portion of the transmitted first image is reflected by the surface 31B of the half mirror 31, and a portion of the light reflected by the mirror surface 32M of the mirror 32 passes through the half mirror 31, thereby being directed along the third optical path OP3 and being acquired by the imaging means 2. A portion of the first image that has passed through the second optical path OP2 passes through the half mirror 51 (without changing direction), and a portion of the transmitted first image is reflected by the surface 31A of the half mirror 31, thereby being directed along the third optical path OP3 and being acquired by the imaging means 2.

[0028] The light source 40 constituting the first illuminator 4 is a compact light source such as an LED. As shown in Fig. 3(a), a portion of the light emitted from the light source 40 toward the half mirror 41 is reflected by a surface 41A of the half mirror 41, and coaxial light L4 parallel to the first optical path OP1 is emitted onto the surface (first surface) on the upper side in the Z direction. The light source 50 of the second illuminator 5 is also a compact light source such as an LED. As shown in Fig. 3(b), a portion of the light emitted from the light source 50 toward the half mirror 41 is reflected by a surface 51A of the half mirror 51, and coaxial light L5 parallel to the second optical path OP2 is emitted onto the surface (second surface) on the lower side in the Z direction.

[0029] As shown in Figure 3, the light emitted from light source 40 can illuminate the upper surface coaxially, and the light emitted from light source 50 can illuminate the lower surface coaxially. This allows for brightening of the first and second images, and by increasing the depth of focus, it becomes easier to obtain a clear image.

[0030] In the configuration of the two-field recognition means 1 shown in Figure 1, there is almost no influence of the light emitted by the light source 40 on the image passing through the second optical path OP2, and almost no influence of the light emitted by the light source 50 on the image passing through the first optical path OP1. For this reason, the imaging means 2 can acquire the first image and the second image simultaneously, but is not limited to this, and the on / off timing of the light sources 40 and 50 may be staggered, and the first image and the second image may be acquired individually accordingly.

[0031] Incidentally, as shown in Figure 2, in the optical element 3 constituting the two-field recognition means 1, the first image passing through the first optical path OP1 is guided to the third optical path OP3 via reflection and transmission by the half mirror 31, while the second image passing through the second optical path OP2 is guided to the third optical path OP3 via reflection only by the half mirror 31. For this reason, the first image is darker when there is no first illumination 4 and second illumination 5. For this reason, it is desirable to increase the illuminance of the light source 40 compared to the light source 50 in order to equalize the brightness of the first and second images acquired by the imaging means 2. On the other hand, there is no particular reason to differentiate the characteristics of the half mirror 41 and the half mirror 51, and it is preferable to use ones with the same specifications.

[0032] As described above, the two-field recognition means 1 equipped with a first illumination 4 and a fifth illumination as shown in Figure 1 makes it easy to obtain a clear image by increasing the depth of field. However, it is unavoidable that it will be larger than the two-field recognition means 110 shown in Figure 10 due to the inclusion of the first illumination 4 and the second illumination. However, by using LEDs for the light sources 40 and 50, the light source section can be easily miniaturized, and the half mirrors 41 and 51 can also be made smaller and lighter. Furthermore, since the direction of light reflected by the half mirrors 41 and 51 does not require as precise angle adjustment as image reflection, adjustment jigs attached to the half mirrors 41 and 51 are almost unnecessary. For this reason, the increase in size and weight due to the inclusion of the first illumination 4 and the second illumination 5 is relatively small, and it does not lose its compact and lightweight characteristics compared to the two-field recognition means 100 equipped with two imaging means as shown in Figure 9.

[0033] However, an increase in thickness in the vertical direction (Z direction) is unavoidable due to the provision of the first illuminator 4 and the second illuminator 5. In order to avoid this increase in thickness as much as possible, as a first modification of the present invention shown in Fig. 4, a two-field-of-view recognition means 101 may be configured such that only the first illuminator 4 on the side where the image is darkened by the optical element 3 (first image) is left, a half mirror 21 is provided between the optical element 3 and the imaging means 2, and a light source 20 that radiates light toward the half mirror 31 is provided.

[0034] In the two-field-of-view recognition means 101 in Fig. 4, the light source 40 and the half mirror 41 form the first illumination 4 that irradiates the coaxial light L4 only to the upper side (+ side in the Z direction) as in Fig. 3(a) (Fig. 5(a)). On the other hand, the light source 20 and the half mirror 21 have the function of irradiating the coaxial light (coaxial light L4 and coaxial light L5) to both the upper side (+ side in the Z direction) and the lower side (- side in the Z direction) via the optical element 3 as in the case of the two-field-of-view recognition means 111 in Fig. 12 (Fig. 5(b)).

[0035] 5(b), in a state in which only the light source 20 is turned on, the coaxial light L4 has a lower illuminance than the coaxial light L5 by passing through the optical element 3. Furthermore, even if the illuminance of the coaxial light L4 and the coaxial light 5 are the same, the first image on the upper side (positive side in the Z direction) becomes darker than the second image on the lower side (negative side in the Z direction) due to the optical element 3. For this reason, it is desirable that the illuminance of the coaxial light L4 irradiated to the upper side (positive side in the Z direction) by turning on only the light source 40 in FIG. 5(a) be equal to or greater than the illuminance of the coaxial light L5 irradiated to the lower side (negative side in the Z direction) in the state of FIG. 5(b).

[0036] In the two-viewpoint recognition means 110 shown in Fig. 10, there are cases where the image on the upper side (+ side in the Z direction) is dark, but the image on the lower side (- side in the Z direction) is not insufficiently bright. In such cases, as in Modification 2 of the present invention shown in Fig. 6, a two-viewpoint recognition means 102 may be provided with a light source 40 and a half mirror 41 for irradiating coaxial light L4 only on the upper side (+ side in the Z direction).

[0037] The above has described an embodiment equipped with the optical element 3 composed of the half mirror 31 and the mirror 32, but a dichroic prism may be used to superimpose the images guided through the first optical path OP1 and the second optical path OP2 in Fig. 2 onto a third optical path perpendicular to both optical paths. Fig. 7 shows the configuration of a two-viewpoint recognition means 103 according to a second embodiment of the present invention.

[0038] In the two-viewpoint recognition means 103 of FIG. 7, an optical element 300 made of a dichroic prism is used instead of the optical element 3 in the two-viewpoint recognition means 1 of FIG. 1. In the dichroic prism 300, the color (wavelength) of the light that is orthogonal to the direction from the first optical path OP1 to the third optical path OP3 is different from the color of the light that is orthogonal to the direction from the second optical path OP2 to the third optical path OP3. For this reason, although white light sources may be used for the light source 40 and the light source 41, it is preferable to use light sources of different colors (wavelengths) to match the characteristics of the optical element 300. That is, the optical element 300 of FIG. 7 is a dichroic prism in which the reflective surface 304M reflects the color of the light source 40 and guides it from the first optical path OP1 to the third optical path OP3, and the reflective surface 305M reflects the color of the light source 50 (which has a different color from the light source 40) and guides it from the second optical path OP2 to the third optical path OP3.

[0039] As explained in the above embodiments, the present invention makes it possible to illuminate the surface of the image acquisition target with coaxial light while being small and lightweight, and to easily acquire clear images by increasing the depth of focus in both fields of view. This enables high-speed and high-precision alignment in mounting work, etc., thereby shortening takt time. [Explanation of symbols]

[0040] 1 2 visual field recognition means 2. Imaging means 3 Optical elements 4. First Illumination 5. Second lighting 21 Half Mirror 21A, 21B (half-mirror) surface 31 Half Mirror 31A, 31B (half-mirror) surface 32 Mirror 32M mirror surface 40 light source 41 Half Mirror 41A, 41B (half-mirror) surface 50 light source 51 Half Mirror 51A, 51B (half-mirror) surface 300 optical elements L4, L5 coaxial light OP1 1st optical path OP2 2nd optical path OP3 3rd optical path

Claims

1. A two-view recognition means that is disposed between a first surface and a second surface in a state where the first surface and the second surface are opposed to each other in parallel, and that is capable of acquiring a first image on the first surface side and a second image on the second surface side, a first optical path that guides the first image; a second optical path for guiding the second image; a third optical path perpendicular to the first optical path and the second optical path; an optical element that guides the first image and the second image to the third optical path while superimposing the first image and the second image; an imaging means for capturing the first image and the second image guided to the third optical path; a two-view recognition means provided with illumination for providing coaxial light parallel to the first optical path and irradiating the first surface, or coaxial light parallel to the second optical path and irradiating the second surface;

2. The two-view recognition means according to claim 1, The illumination is a two-view recognition means that is arranged in the first optical path and irradiates the first surface with coaxial light parallel to the first optical path, or is arranged in the second optical path and irradiates the second surface with coaxial light parallel to the second optical path.

3. The two-view recognition means according to claim 2, The illumination is a two-view recognition means configured by a first illumination arranged in the first optical path and irradiating the first surface with coaxial light parallel to the first optical path, and a second illumination arranged in the second optical path and irradiating the second surface with coaxial light parallel to the second optical path.

4. The two-view recognition means according to any one of claims 1 to 3, the optical element includes a half mirror and a mirror, The light incident from either the first optical path or the second optical path is reflected by the half mirror and guided to the third optical path, The two-view recognition means reflects the light incident from the other side, the transmitted portion of which is transmitted by the half mirror, and guides the light reflected by the half mirror and the transmitted portion of which is transmitted by the half mirror, to the third optical path.

5. The two-view recognition means according to any one of claims 1 to 3, the optical element is a dichroic prism, a first color, which is the color of the light emitted by the first lighting, and a second color, which is the color of the light emitted by the second lighting, are different from each other; The dichroic prism is a two-view recognition means having a first reflecting surface that reflects the first image of the first color onto the third optical path and a second reflecting surface that reflects the second image of the second color onto the third optical path.

6. The two-view recognition means according to claim 3, When acquiring the first image, only the first illumination is turned on; a two-view recognition means for turning on only the second illumination when acquiring the second image;

Images