TWI573998B - Optical inspection device - Google Patents

Description

Optical detection device

The present invention relates to an optical detecting device.

With the advancement of technology, more and more electronic products are beginning to use metal materials as the shell to increase the aesthetics of the products. The metal casing can be machined (e.g., a milling machine or a lathe) to obtain the desired shape and features that can be imaged for inspection using optical instruments. However, after processing, the metal surface may become rough (for example, the stencil generated by the processing), so that the image captured by the optical instrument may contain information on the rough surface, making the measurement unstable or even impossible to measure. The characteristics to be detected.

One aspect of the present invention provides an optical detecting apparatus including an image taking device, a surface light source, and a holder. The image taking device has an image taking position. The surface light source is placed between the image capturing device and the image taking position. The surface light source includes a light guide plate and a light emitting element. The light guide plate has a first light emitting surface, a second light emitting surface and a light incident surface. The first light emitting surface is opposite to the two light emitting surfaces, and the light incident surface is connected to the first light emitting surface and the second light emitting surface. The image capturing device is disposed facing the second light emitting surface of the light guide plate. The light emitting element is disposed facing the light incident surface of the light guide plate. Light beam emitted by the light-emitting element The surface enters the light guide plate, and the first light exiting surface of the light guide plate exits and enters the image capturing position, and the light beam reflected from the image capturing position penetrates the first light emitting surface and the second light emitting surface of the light guiding plate to enter the image capturing device. The fixing frame connects the image capturing device and the surface light source, and at least surrounds a space between the image capturing device and the surface light source.

In the above embodiment, the surface light source is disposed between the image capturing device and the image capturing position, so that the light beam does not form a shadow of the image capturing device on the object to be tested, and the setting is a shadowless detecting device, and The optical detecting device of the embodiment has a large degree of freedom in selecting the working distance of the image capturing device. In addition, the image of the object to be tested captured by the optical detecting device of the above embodiment can be enhanced, and the image of the rough surface is suppressed, so that the feature of the object to be tested can be highlighted to obtain a clear object to be tested. Feature image. The holder isolates ambient light.

100‧‧‧Image capture device

102‧‧‧ Receiving surface

110‧‧‧Image location

200‧‧‧ surface light source

210‧‧‧Light guide plate

212‧‧‧The first glazing

214‧‧‧Second glazing

216‧‧‧ into the glossy surface

220‧‧‧Lighting elements

222, 224 ‧ ‧ beam

230‧‧‧scattering elements

232‧‧‧Black cover

234‧‧‧White particles

300‧‧‧ fixed frame

900‧‧‧Test object

D‧‧‧Working distance

Fig. 1 is a schematic view showing an optical detecting device according to an embodiment of the present invention.

Fig. 2 is an enlarged view of the surface light source of Fig. 1.

Fig. 3 is a top view of the light guide plate of Fig. 1.

The embodiments of the present invention are disclosed in the following drawings, and for the purpose of clarity However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the present invention, these practical details are not necessarily need. In addition, some of the conventional structures and elements are shown in the drawings in a simplified schematic manner in order to simplify the drawings.

Fig. 1 is a schematic view showing an optical detecting device according to an embodiment of the present invention. The optical detecting device includes the image capturing device 100 and the surface light source 200. The image capturing device 100 has an image capturing position 110. The image capturing device 100 is substantially separated from the image capturing device 100 by a working distance D of the image capturing device 100. Therefore, the image capturing device 100 mainly captures an image of the object to be tested 900 placed in the image capturing position 110. The surface light source 200 is placed between the image capturing device 100 and the image capturing position 110. The surface light source 200 includes a light guide plate 210 and a light emitting element 220. The light guide plate 210 has a first light emitting surface 212, a second light emitting surface 214, and a light incident surface 216. The first light-emitting surface 212 is opposite to the second light-emitting surface 214 , and the light-incident surface 216 is connected to the first light-emitting surface 212 and the second light-emitting surface 214 . The image capturing device 100 is disposed facing the second light emitting surface 214 of the light guide plate 210. The light emitting element 220 is disposed facing the light incident surface 216 of the light guide plate 210. The light beam 222 emitted from the light-emitting element 220 enters the light guide plate 210 from the light-incident surface 216, exits from the first light-emitting surface 212 of the light guide plate 210, and enters the image capturing position 110, and the light beam 224 reflected from the image capturing position 110 penetrates the light guide plate 210. The first light-emitting surface 212 and the second light-emitting surface 214 enter the image capturing device 100.

In the present embodiment, the surface light source 200 is placed between the image capturing device 100 and the image capturing position 110, so that the light beam 222 does not form a shadow on the image capturing device 100 on the object to be tested 900. Type detection device. Moreover, the height of the surface light source 200 is smaller than the length and the width, so even if the image capturing apparatus 100 has a small working distance D, the surface light source 200 can be placed between the image capturing device 100 and the image capturing position 110. . In other words, this is The optical detecting device of the embodiment has a large degree of freedom in selecting the working distance D of the image capturing device 100. For the large-diameter image capturing device 100, the working distance D does not need to be increased accordingly (relative to the light source system using the 45-degree beam splitter, the size of the light source increases as the aperture of the image capturing device increases), so there is no The problem that the size of the light source is too large to obscure the viewing angle (such as lateral light collection). In addition, in some embodiments, the object to be tested 900 may be a metal casing, such as a metal casing that is machined and has a knife surface. For a rough surface of the object to be tested 900, the image of the object to be tested 900 captured by the optical detecting device of the present embodiment can be enhanced, and the image of the rough surface is suppressed, so that the characteristics of the object to be tested 900 are Can be highlighted to obtain a clear feature image of the object to be tested 900. In other words, the surface light source 200 is capable of filtering image noise caused by the rough surface of the object to be tested 900, thereby leaving the features of the object to be tested 900. In this way, the object to be tested 900 can be tested without surface treatment (for example, sand blasting), which greatly simplifies the process.

In the present embodiment, the light-emitting element 220 can be a light bar, such as a light-emitting diode light bar, but the invention is not limited thereto. The wavelength of the light beam 222 emitted by the light-emitting element 220 can be adjusted according to the actual situation to match the light-receiving band of the image capturing device 100. For example, the wavelength of the light-emitting element 220 can be in the wavelength range of visible light.

Next, please refer to FIG. 1 and FIG. 2 together, and FIG. 2 is an enlarged view of the surface light source 200 of FIG. In the present embodiment, the surface light source 200 further includes a plurality of scattering elements 230 disposed on the second light-emitting surface 214 of the light guide plate 210. When the beam 222 is incident on the scattering element 230, the scattering element 230 can change the direction of travel of the beam 222, such that the beam 222 can be caused to be on the light guide plate 210. The light beam 222 incident from the light incident surface 216 is guided to the first light exit surface 212 to allow the light beam 222 to exit the light guide plate 210 from the first light exit surface 212. The object to be tested 900 located at the image capturing position 110 of the image capturing apparatus 100 is irradiated.

In FIG. 2, the size of the scattering element 230 is exaggerated to exhibit its internal features. However, in practical applications, the size of the scattering element 230 can be smaller than that of the image capturing apparatus 100 (as shown in FIG. 1). Further, the scattering element 230 can be located outside the depth of field of the image capturing device 100, which can reduce the chance of the scattering element 230 being imaged by the image capturing device 100.

Please return to Figure 1. The image capturing device 100 has a working distance D, and the surface light source 200 can be placed between the image capturing device 100 and one of the half working distances D of the image capturing device 100. For example, if the working distance D of the image capturing device 100 is about 300 mm, the surface light source 200 can be placed at a distance of about 0 mm to about 150 mm from the image capturing device 100. In this way, the surface light source 200 can be away from the depth of field range of the image capturing apparatus 100, so that the scattering element 230 of FIG. 2 is not imaged on the image capturing apparatus 100. Since the imaging is not performed, the Moire effect between the scattering element 230 and the image sensing element (such as the charge coupled device (CCD) of the image capturing device 100 can be avoided. Therefore, the surface light source 200 and the image capturing device 100 can be omitted. Special adjustments or relative rotations are required to eliminate the Moire effect.

Please refer to Figure 2. At least one of the scattering elements 230 includes a black cover layer 232 and white particles 234. The white particles 234 are disposed between the black cover layer 232 and the second light exit surface 214 of the light guide plate 210. The white particles 234 can cause the beam 222 to scatter, while the black cover layer 232 can absorb or block the beam 222. Specifically, when the light beam 222 hits the scattering element 230, white The particles 234 are capable of causing the beam 222 to scatter, that is, the beam 222 can be radiated as a center of the white particles 234 (Fig. 2 only shows the path of the partial beam 222). Since the black cover layer 232 covers the white particles 234, the partial light beam 222 that is scattered upward (ie, toward the image taking device 100 of FIG. 1) is blocked or absorbed by the black cover layer 232, so that the light beam 222 cannot be lifted upward. Leaving the light guide plate 210. On the other hand, another portion of the light beam 222 that is scattered downward (i.e., in the direction of the image capturing position 110 of FIG. 1) is blocked or absorbed by the black covering layer 232, so that the portion of the light beam 222 can be made of the first light emitting surface. 212 leaves the light guide plate 210 and is then irradiated to the object to be tested 900 (as shown in FIG. 1). In this way, the light guide plate 210 can guide the light beam 222 emitted by the light emitting element 220 to the object to be tested 900.

In some embodiments, the black cover layer 232 can completely cover the white particles 234, for example, the white particles 234 are co-coated with the black cover layer 232 by the light guide plate 210. In this way, the probability that the light beam 222 leaves the light guide plate 210 upward can be greatly reduced. Therefore, the image capturing device 100 does not receive the light of the portion, and does not interfere with the image of the object to be tested 900.

Please refer to Figure 1 and Figure 2 together. After the light guide plate 210 guides the light beam 222 to the image capturing position 110 of the image capturing device 100, the light beam 222 is irradiated to the object to be tested 900. The light beam 224 reflected from the object to be tested 900 then returns to the surface light source 200, and sequentially passes through the first light-emitting surface 212 and the second light-emitting surface 214 of the light guide plate 210, and is received by the image capturing device 100, so that the image capturing device is obtained. 100 can obtain the image of the object to be tested 900 (the first and second figures only show the path of the partial beam 224).

Please refer to FIG. 1 and FIG. 3 together, wherein FIG. 3 is a top view of the light guide plate 210 of FIG. 1. In some embodiments, in order to enable the beam 222 to penetrate the second illuminating surface 214, the scattering element 230 can cover an area of about 20% to about 25% of the second illuminating surface 214. Where the scattering element 230 is covered, the beam 224 fails to pass, and the beam 224 passes through a portion of the second exit surface 214 that is not covered by the scattering element 230. In this way, the scattering element 230 can simultaneously achieve the purpose of guiding the light beam 222 to the image capturing position 110 of the image capturing device 100 and not blocking the light beam 224 from passing.

Then please return to Figure 1. In some embodiments, the optical detecting device further includes a fixing frame 300 that connects the image capturing device 100 and the surface light source 200 and at least surrounds a space between the image capturing device 100 and the surface light source 200. Specifically, the intensity of the light beam 224 passing through the surface light source 200 may be weakened by the thickness of the surface light source 200, and thus the ambient light obliquely incident on the image capturing apparatus 100 may exacerbate interference with the image. However, in the present embodiment, the fixing frame 300 can be a material that is opaque, so that ambient light can be isolated to reduce the probability that the image capturing device 100 receives ambient light. The holder 300 can also fix the distance between the surface light source 200 and the image capturing device 100 and the surface light source 200. For example, the scattering element 230 of the surface light source 200 (shown in FIG. 2) is placed outside the depth of field of the image capturing device 100.

In the present embodiment, the image capturing device 100 is, for example, a camera, and further has a light receiving surface 102, and the light beam 224 enters the image capturing device 100 from the light receiving surface 102. The light-receiving surface 102 of the image capturing device 100 is substantially parallel to the second light-emitting surface 214 of the surface light source 200, and the surface light source 200 completely covers the light-receiving surface 102 of the image capturing device 100, that is, the light beam 224 entering the light-receiving surface 102 is first Surface light source 200. In some embodiments, as the thickness of the surface light source 200 is different, the back focus distance of the image capturing device 100 may also change. In this case, the thickness of the surface light source 200 can be taken into consideration in the lens design of the image capturing device 100, or the focusing device or the extension ring can be added to the image capturing device 100 to adjust the focal length thereof to obtain a suitable focal length.

Please refer to Figure 2 below. In some embodiments, the light incident surface 216 of the light guide plate 210 is substantially perpendicular to the first light exit surface 212 and is also substantially perpendicular to the second light exit surface 214 of the light guide plate 210. In other words, if the first light-emitting surface 212 and the second light-emitting surface 214 are the main surfaces of the light guide plate 210, the light-incident surface 216 can be the side surface of the light guide plate 210. Therefore, the light beam 222 emitted by the light-emitting element 220 is laterally incident. .

Please refer to Figure 1 and Figure 2 together. In response to the above, the light beam 222 emitted by the light-emitting element 220 emits light laterally, and the light guide plate 210 rotates the light beam 222 into the longitudinal direction, and then exits the light guide plate 210 from the first light-emitting surface 212 to illuminate the object to be tested 900. The light beam 224 reflected from the object to be tested 900 is incident on the image capturing device 100 after passing through the light guide plate 210 in the longitudinal direction. In other words, the image capturing device 100 is longitudinally received, so that the light collecting direction is different from the light emitting direction of the light emitting element 220. For example, the light receiving direction of the image capturing device 100 may be substantially perpendicular to the light emitting direction of the light emitting element 220.

In summary, in the above embodiment, the surface light source is placed between the image capturing device and the image taking position, so that the light beam does not form a shadow of the image capturing device on the object to be tested. Moreover, even if the image capturing device has a small working distance, the surface light source can be placed between the image capturing device and the image capturing position. In addition, for a rough surface test object, the optical detecting device of the above embodiment The image of the object to be tested can be enhanced, and the image of the rough surface is suppressed, so that the feature of the object to be tested can be highlighted to obtain a clear image of the object to be tested, so that the object to be tested can be passed without Surface treatment can be used for inspection, which greatly simplifies the process.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

100‧‧‧Image capture device

102‧‧‧ Receiving surface

110‧‧‧Image location

200‧‧‧ surface light source

210‧‧‧Light guide plate

212‧‧‧The first glazing

214‧‧‧Second glazing

216‧‧‧ into the glossy surface

220‧‧‧Lighting elements

222, 224 ‧ ‧ beam

300‧‧‧ fixed frame

900‧‧‧Test object

D‧‧‧Working distance

Claims (10)

An optical detecting device comprising: an image capturing device having an image capturing position; and a light source disposed between the image capturing device and the image capturing position, the surface light source comprising: a light guide plate having a first light output a second light-emitting surface and a light-incident surface, wherein the first light-emitting surface is opposite to the second light-emitting surface, and the light-incident surface is connected to the first light-emitting surface and the second light-emitting surface, wherein the image capturing device Facing the second light-emitting surface of the light guide plate; a light-emitting element is disposed facing the light-incident surface of the light guide plate, wherein the light beam emitted by the light-emitting element enters the light guide plate from the light-incident surface, and the light guide plate The first light exiting surface exits and enters the image capturing position, and the light beam reflected from the image capturing position penetrates the first light emitting surface and the second light emitting surface of the light guide plate to enter the image capturing device; and a fixed And connecting the image capturing device and the surface light source, and at least surrounding a space between the image capturing device and the surface light source. The optical detecting device of claim 1, wherein the surface light source further comprises a plurality of scattering elements disposed on the second light emitting surface of the light guide plate. The optical detecting device of claim 2, wherein at least one of the scattering elements comprises: a black cover layer; A white particle is disposed between the black cover layer and the second light exiting surface of the light guide plate. The optical detecting device of claim 3, wherein the black cover layer completely covers the white particles. The optical detecting device of claim 2, wherein the scattering elements cover an area of about 20% to about 25% of the second illuminating surface. The optical detecting device of claim 1, wherein the image capturing device has a working distance, and the surface light source is disposed between the image capturing device and one of the working distances of the image capturing device. The optical detecting device of claim 1, wherein the light incident surface of the light guide plate is substantially perpendicular to the first light exiting surface and substantially perpendicular to the second light exiting surface of the light guide plate. The optical detecting device of claim 1, wherein a light emitting direction of the light emitting element of the surface light source is different from a light receiving direction of the image capturing device. The optical detecting device of claim 1, wherein the image capturing device further has a light collecting surface, the surface light source completely covering the light receiving surface of the image capturing device. The optical detecting device of claim 9, wherein the light receiving surface of the image capturing device is substantially parallel to the second light emitting surface of the surface light source.