JP2013228404A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device having a compact structure, capable of effectively recognizing the contour of various substrates including transparent substrates.SOLUTION: An imaging device includes: a substrate supporting sheet 21 which supports a sapphire substrate S; an imaging element 18; a first light source 12 having an opening 15 at the central part for passing light, from which light is emitted for irradiation of the periphery of the sapphire substrate S; a beam splitter 16; a second light source 11 from which light is emitted and reflected by the beam splitter 16 so as to pass through the opening 15 for irradiation of the central part of the sapphire substrate S; and an image forming lens 17 for introducing light reflected by the surface of the sapphire substrate S to the imaging element 18.

Description

  The present invention relates to an imaging device for recognizing the outer shape of a substrate, and more particularly to an imaging device capable of effectively recognizing the outer shape of a transparent substrate such as a sapphire substrate.

  For example, in order to divide a sapphire substrate on which a device pattern for producing a blue LED is formed on a surface thereof, first, a division starting point is specified. At this time, the sapphire substrate may be cracked in a polishing process or the like. For this reason, in order to specify the division starting point, it is necessary to photograph the entire surface of the sapphire substrate and recognize the outer shape by binarization processing or the like.

Conventionally, as described in Patent Document 1, for example, the entire surface of a light-transmitting wafer is photographed using transmitted illumination.
JP-A-5-52538

  However, when a transparent substrate such as a light transmissive wafer is detected using transmitted illumination, there is a problem in that the recognition accuracy of the outer shape deteriorates because the contrast is low.

  For this reason, it is preferable to detect the transparent substrate using specularly reflected light. In this case, however, a lens having a larger diameter than the transparent substrate and a large light source sufficient to cover the lens are required, and the apparatus is expensive. And the problem that it enlarges arises.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an imaging apparatus that can effectively recognize the outer shapes of various substrates including a transparent substrate while having a compact configuration. And

The invention according to claim 1 is an imaging device for recognizing the outer shape of the substrate, and includes a substrate support member that supports the substrate, an image sensor, and an opening through which light passes in the center. A first light source that irradiates light to an outer peripheral portion of a substrate supported by the support member; a beam splitter disposed opposite to an opening in the first light source; the beam splitter and the first light source; A second light source that irradiates light to the central portion of the substrate supported by the support member through the opening in the substrate, and the substrate is irradiated from the first light source and reflected on the outer peripheral surface of the substrate; Light that has passed through the opening in the first light source, and light that has passed through the opening in the first light source after being reflected from the surface of the central portion of the substrate after being irradiated on the substrate from the second light source. Before through the beam splitter An imaging lens for taking the image pickup device, characterized in that it and a light diffusing plate disposed on the light emitting portion of the first light source and the second light source.

According to one aspect of the present invention, prior Symbol first light source and the second light source has a configuration in which arrayed multiple the LED.

According to one aspect of the present invention, light diffusing plate disposed on the light emitting portion of the front Symbol first light source, the thickness of the vicinity of the opening is thinner than other parts.

According to one aspect of the present invention, prior Symbol substrate is a transparent substrate made of sapphire.

  According to the first aspect of the present invention, it is possible to effectively recognize the outer shapes of various substrates including a transparent substrate while having a compact configuration.

In addition, according to the first aspect of the present invention, it is possible to improve the illuminance distribution of the light emitted from the light source.

According to invention of Claim 1 , the shape of a 1st light source and a 2nd light source can be set arbitrarily.

According to the invention described in claim 1, it is possible to equalize the amount of the boundary portion of the light emitted from the light and a second light source which is irradiated from the first light source to the substrate board.

According to the first aspect of the invention, it is possible to accurately recognize the outer shape of the transparent sapphire substrate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of an imaging apparatus according to the present invention.

  This imaging device is for recognizing the outer shape of the transparent sapphire substrate S, and includes a substrate support sheet 21 that supports the sapphire substrate S, a table 22 that supports the substrate support sheet 21, and a central portion thereof. A substantially cylindrical first light source 12 having an opening 15 through which light passes, a beam splitter 16 such as a half mirror disposed to face the opening 15 in the first light source 12, and a beam splitter 16 The second light source 11, the imaging lens 17, an image sensor 18 such as a CCD camera, and an image processing unit 19 are provided.

  The board | substrate support sheet 21 has a translucent sheet | seat which has adhesiveness in the support part, and supports the sapphire board | substrate S in the state which adhered. Moreover, the table 22 is comprised from a translucent member. For this reason, it becomes possible to observe the sapphire substrate S from below (table 22 side).

  As described above, the first light source 12 has a substantially cylindrical shape having an opening 15 through which light passes at the center portion thereof, that is, a substantially donut shape, and the light emitting portion has a hollow circular shape. Yes. A light diffusing plate 14 is disposed in the light emitting portion of the first light source 12. Moreover, the 2nd light source 11 has a substantially cylindrical shape, and the light emission part is circular. A light diffusing plate 13 is disposed in the light emitting portion of the second light source 11. The first light source 12 and the second light source 11 have a configuration in which a plurality of LEDs are arranged inside. For this reason, the shape of the 1st light source 12 and the 2nd light source 11 can be set arbitrarily.

The light emitted from the first light source 12 is applied to the outer peripheral portion (other than the central portion) of the sapphire substrate S and the outer portion of the sapphire substrate S as indicated by arrows in FIG. Further, light emitted from the second light source 11 is reflected at the beam splitter 16, passes through an opening 15 in the first light source 12 is irradiated to the center portion of the sapphire substrate S. In this embodiment, the second light source 11 constitutes a coaxial epi-illumination using a beam splitter 16.

Arrows in FIG. 1, is emitted from the first light source 12 or the second light source 11, it shows a principal ray of the light regularly reflected by the surface of the sapphire substrate S or the substrate support sheet 21.

  FIG. 2 is an explanatory diagram showing the relationship between the light irradiation range by the first light source 12 and the second light source 11 and the sapphire substrate S. FIG.

The light emitted from the second light source 11 is applied to a circular region at the center of the sapphire substrate S, which is denoted by reference numeral E1 in FIGS. On the other hand, the light emitted from the first light source 12 is irradiated to a region other than the region E1 at the outer peripheral portion of the sapphire substrate S and the outer portion of the sapphire substrate S, which is denoted by reference numeral E2 in FIGS. For this reason, the first light source 12 and the second light source 11 can efficiently irradiate the sapphire substrate S and the region of the outer portion thereof with light.

  Note that the opening 15 in the first light source 12 functions as an aperture stop for the second light source 11. At this time, in the first light source 12, the LED cannot be disposed up to the end on the opening 15 side, so that the first light source 12 emits light and the second light source 11 emits light. A phenomenon occurs in which the amount of light applied to the sapphire substrate S decreases at the boundary with the region. For this reason, the light diffusing plate 14 disposed in the light emitting portion of the first light source 12 is configured such that the thickness near the opening 15 is thinner than the other portions.

  FIG. 3 is a partially enlarged view showing the shape in the vicinity of the opening 15 of the light diffusing plate 14 disposed in the light emitting portion of the first light source 12.

  As shown in FIG. 3A, a tapered portion is formed in a region at a distance L from the opening 15 in the light diffusing plate 14 disposed in the light emitting portion of the first light source 12. And the thickness d of the edge part by the side of the opening part 15 in the light diffusing plate 14 is smaller than thickness D other than a taper part. At this time, the thickness D is 2 mm, the thickness d is 1 mm, and the distance L is 15 mm, for example.

  In addition to providing the tapered portion as shown in FIG. 3A, by providing the rounded portion as shown in FIG. 3B, the thickness in the vicinity of the opening 15 in the light diffusing plate 14 is another portion. It may be made thinner.

  Referring to FIG. 1 again, the light emitted from the first light source 12 and specularly reflected by the surface of the sapphire substrate S and the substrate support sheet 21 outside the sapphire substrate S is reflected in the opening 15 in the first light source 12 and The beam passes through the beam splitter 16 in sequence and is taken into the image sensor 18 by the imaging lens 17. In addition, the light emitted from the second light source 11 and specularly reflected by the surface of the sapphire substrate S sequentially passes through the opening 15 and the beam splitter 16 in the first light source 12 and passes through the imaging lens 17 to the image sensor 18. It is captured.

  Then, the image sensor 18 transmits the captured light amount data to the image processing unit 19. The image processing unit 19 binarizes the light amount data and creates contour data of the sapphire substrate S.

  FIG. 4 is an explanatory diagram showing a state in which the cracked sapphire substrate S is scanned with a straight line L, and FIG. 5 is a graph showing the measurement results at that time. 5A shows a measurement result obtained by performing measurement using specular reflection light by the above-described imaging apparatus, and FIG. 5B shows a measurement result obtained by performing measurement using transmitted illumination. ing.

  As shown in these figures, when the sapphire substrate S is measured using specular reflection, the S / N ratio is large, and a large difference in measured value occurs between a portion where the sapphire substrate S is present and a portion where the sapphire substrate S is not present. On the other hand, when the sapphire substrate S is measured using transmitted illumination, there is no significant difference between the light transmittance of the sapphire substrate S and the light transmittance of the resin sheet portion of the substrate support sheet 21. For this reason, the S / N ratio is small, and there is almost no difference in measured values between the portion with and without the sapphire substrate S. As is clear from these figures, it is possible to effectively recognize the outer shape of the substrate by using the specularly reflected light.

In the embodiment described above, a cylindrical opening 15 having a circular cross section is provided at the center of the first light source 12. However, the shape of the opening may be another shape such as a rectangular cross section. However, since a problem such as a decrease in the amount of emitted light occurs at the corner, the cross section is preferably circular.

  In the above-described embodiment, the substrate to be imaged by the imaging apparatus according to the present invention is the transparent sapphire substrate S. In addition to sapphire, for example, a transparent material such as quartz, glass, or transparent plastic is used. It may be replaced with various types of substrates. As described above, the substrate to be imaged by the apparatus according to the present invention is effective against the transparent substrate such as sapphire, quartz, glass, or plastic. Can be recognized.

In the embodiment described above, the second light source 1 1 is arranged at a position where the light emitted from the second light source 11 is irradiated to the sapphire substrate S is reflected on the beam splitter 16, the image pickup device 18 Is arranged at a position where the light specularly reflected by the sapphire substrate S passes through the beam splitter 16 and is taken in, but the arrangement of the second light source 11 and the image sensor 18 may be interchanged. That is, the second light source 11 is disposed at a position where the light emitted from the second light source 11 passes through the beam splitter 16 and irradiates the sapphire substrate S, and the image sensor 18 is regularly reflected by the sapphire substrate S. You may arrange | position in the position where the light which reflected the beam splitter 16 takes in.

1 is a schematic diagram of an imaging apparatus according to the present invention. It is explanatory drawing which shows the relationship between the irradiation range of the light by the 1st light source 12 and the 2nd light source 11, and the sapphire substrate S. FIG. FIG. 4 is a partially enlarged view showing a shape in the vicinity of an opening 15 of a light diffusing plate 14 disposed in a light emitting part of a first light source 12. It is explanatory drawing which shows the state which scanned the sapphire substrate S which the crack produced in the straight line L. FIG. It is a graph which shows a measurement result.

DESCRIPTION OF SYMBOLS 11 2nd light source 12 1st light source 13 Light diffusing plate 14 Light diffusing plate 15 Aperture 16 Beam splitter 17 Imaging lens 18 Image sensor 19 Image processing part 21 Substrate support sheet 22 Table S Sapphire substrate

Claims (1)

An imaging device for recognizing the outer shape of a transparent substrate made of sapphire ,
A substrate support member for supporting the substrate;
An image sensor;
A first light source having an opening through which light passes in a central portion and irradiating light to an outer peripheral portion of the substrate supported by the support member;
A beam splitter disposed opposite the opening in the first light source;
A second light source for irradiating light to a central portion of the substrate supported by the support member through the beam splitter and an opening in the first light source;
After the substrate is irradiated from the first light source and specularly reflected on the surface of the outer periphery of the substrate, the light passing through the opening in the first light source and the substrate from the second light source are irradiated to the substrate. An imaging lens for capturing the light that has passed through the opening in the first light source after specular reflection on the surface of the central portion, into the imaging device via the beam splitter;
A light diffusing plate disposed in a light emitting portion of the first light source and the second light source;
An image processing unit that binarizes light amount data captured by the image element and creates contour data of a substrate supported by the support member;
Equipped with a,
The substrate support member has a translucent sheet;
The first light source and the second light source have a configuration in which a plurality of LEDs are arranged in a row,
The imaging apparatus according to claim 1, wherein the light diffusing plate disposed in the light emitting portion of the first light source has a thinner thickness near the opening than other portions .

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