TW201323861A - Non-contact LED inspection device - Google Patents

Abstract

A non-contact type light-emitting diode inspection apparatus according to an embodiment of the present invention is configured to compare a captured image with a target image input in advance as a result of photographing a light-emitting diode with a camera, thereby determining whether the light-emitting diode is good or bad. The inspection device includes: a stage portion on which the light emitting diode is mounted to fix the light emitting diode to an inspection position or a conveyance; and an illumination unit including a first illumination portion and a second illumination portion, wherein The first illumination unit is located above the stage portion, and emits visible light having a wavelength range of blue or less to the light-emitting diode. The second illumination unit is located above the first illumination unit and is irradiated to the light-emitting diode. a visible light in a green wavelength range; a camera positioned above the illumination portion to capture an image of the light emitting diode; and a visual processing unit that reads an image captured by the camera and determines whether the light emitting diode is good or bad; The control unit includes a motion controller that controls the stage portion and the camera portion.

Description

Non-contact LED inspection device

The present invention relates to a light-emitting diode inspection device, and more particularly to a non-contact light-emitting diode inspection device capable of obtaining clear image information about components inside a light-emitting diode.

A light emitting diode (LED) is an electronic component that emits light by a composite of a minority carrier (electron or hole) injected by a p-n bonding structure of a semiconductor. That is, if a forward voltage is applied to the semiconductor of a specific light source, the electrons and the holes are recombined while moving through the joint portion between the anode and the cathode, and become smaller energy than when the electrons and the hole are separated, thus resulting in Light is emitted by the difference in energy.

Recently, due to the improvement of luminous efficiency, the application range of the light-emitting diode has been extended from the initial signal indication to a flat panel display such as a backlight module (BLU) or a liquid crystal display (LCD). Light source and illumination for the device. This is because the light-emitting diode consumes less power and has a longer life than a bulb or a fluorescent lamp that has been used as an illumination.

The light emitting diode can be fabricated as a light emitting diode assembly. In general, a light-emitting diode assembly includes a light-emitting diode chip, a body for mounting a light-emitting diode wafer, and a fluorescent light-emitting diode covering the light-emitting diode chip above the main body. The light emitting diode assembly may further include a Zener diode beside the light emitting diode wafer.

A light-emitting diode wafer is a semiconductor layer in which different conductivity types are grown on a substrate And after the active layer excited between them, an electrode is formed on each semiconductor layer to be fabricated. The LED body and the Zener diode are electrically connected to the lead frame through wire bonding.

In the process of filling the fluorescent ruthenium above the light-emitting diode wafer and the Zener diode, when the fluorescent ruthenium filling is too small, the internal bonding wires are exposed, and may be broken due to heat generation. Conversely, in the case where the fluorescent enamel is excessively filled, it may not be assembled when assembled later in the module, resulting in a defect that the light divergence angle is larger than the set value. Therefore, it is necessary to check the filling state of the fluorescent iridium of the light-emitting diode assembly and the connection state of the bonding wires. As a prior art of the present invention, it will be understood with reference to Korean Patent Publication No. 2009-0053591.

An object of the present invention is to provide a non-contact type light-emitting diode inspection apparatus capable of more clearly obtaining a bonding wire connection state inside a light-emitting diode by vividly comparing images of respective elements of a light-emitting diode. And image information of the pattern of the body of the light emitting diode.

A non-contact type light-emitting diode inspection apparatus according to an embodiment of the present invention is configured to compare a captured image with a target image input in advance as a result of photographing a light-emitting diode with a camera, thereby determining whether the light-emitting diode is good or bad. The device includes a stage portion on which the light emitting diode is mounted to fix the light emitting diode to an inspection position or conveyance, and an illumination unit including a first illumination portion and a second illumination portion, wherein the first illumination portion and the second illumination portion An illuminating portion is located above the stage portion, and illuminates the illuminating diode with visible light having a wavelength range of less than blue, and the second illuminating portion is located above the first illuminating portion and illuminates the illuminating diode a visible light in a green wavelength range; a camera positioned above the illumination portion to capture an image of the light emitting diode; and a visual processing unit that reads an image captured by the camera and determines whether the light emitting diode is good or bad; The control unit includes a motion controller that controls the stage portion and the camera portion.

The first illumination portion may illuminate the light at the Brewster's angle for the light emitting diode.

The non-contact LED inspection device may further include a polarizing filter, the polarizing filter is located in front of the first illumination portion for isolating a specific polarized light component of the light emitted from the first illumination portion, At this time, the polarizing filter can isolate the s-polarized component.

The wavelength below the blue may be 495 nm or less, and the green wavelength may be 495 nm to 570 nm.

The light emitting diode may include a body portion in which a bonding wire and a pattern including a gold (Au) component are formed on the surface.

5‧‧‧Lighting diode

10‧‧‧The Stage Department

20‧‧‧Lighting Department

22‧‧‧First Lighting Department

22a‧‧‧First light

24‧‧‧Second Lighting Department

24a‧‧‧second light

24b‧‧‧ polarizing filter

25‧‧‧Vision assurance department

30‧‧‧ camera

40‧‧‧Visual Processing Department

50‧‧‧Control Department

60‧‧‧Conveyor belt

100‧‧‧ incident light

110‧‧‧ Reflected light

120‧‧‧Media

200‧‧‧ interface

202‧‧‧ normal

θB‧‧‧ Brewster Point

Fig. 1 is a side sectional view showing a non-contact type light-emitting diode inspection apparatus according to an embodiment of the present invention.

Fig. 2 is a graph showing the reflectance of different light wavelengths when light is irradiated to a metal substance.

(a) of FIG. 3 is a view showing a bonding lead portion of the light-emitting diode when the first illumination portion of the original light-emitting diode inspection device supplies visible light in a green wavelength range to the light-emitting diode module. image.

(b) of FIG. 3 is a junction of the light-emitting diodes when the light source provided by the first illumination unit of the non-contact light-emitting diode inspection apparatus according to the embodiment of the present invention is in the visible light range of the blue or lower wavelength range. An image of the lead portion.

Figure 4 is a conceptual diagram showing the principle of Brewster's angle.

(a) of Fig. 5 shows that the light-emitting diode that is the object to be inspected is irradiated with the following blue waves. An image of the body of a light-emitting diode in a long range of visible light.

(b) of FIG. 5 is a view showing that the visible light in the blue wavelength range and the green wavelength range provided by the second illumination portion are provided when the light emitting diode is simultaneously irradiated to the first illumination portion according to an embodiment of the present invention. An image of a light-emitting diode obtained in the visible light.

Fig. 6 is a side view showing the entire non-contact type light emitting diode inspection apparatus of one embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

However, the embodiments of the present invention can be modified into various different forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Therefore, the shapes, sizes, and the like of the elements in the drawings may be exaggerated for the sake of clarity, and the elements denoted by the same reference numerals in the drawings are the same elements.

Fig. 1 is a side sectional view showing a non-contact type light-emitting diode inspection apparatus according to an embodiment of the present invention. Fig. 6 is a side view showing the entire non-contact type light-emitting diode inspection apparatus of one embodiment of the present invention. As shown in FIGS. 1 and 6, the non-contact type light emitting diode inspection apparatus includes a stage unit (10), an illumination unit (20), a camera (30), a visual processing unit (40), and a control unit ( 50).

The stage portion (10) provides a space in which the light-emitting diode (5) as an inspection object is placed. The stage portion (10) may include a position adjusting portion (not shown) and a fixing portion (not shown) for adjusting and fixing the position of the light emitting diode (5).

The illumination unit (20) is located above the stage portion (10). The illumination unit (20) provides illumination to the light-emitting diode (5) for ensuring accurate image information of the light-emitting diode (5). A plurality of lamps are disposed on the outer side surface of the field-of-view securing portion (25) penetrating the center so that the lamps illuminate the light-emitting diodes (5) around.

The illumination unit (20) includes a first illumination unit (22) and a second illumination unit (24).

The first illumination unit (22) is mounted below the illumination unit (20), and supplies the light-emitting diode (5) with a light source that is incident at a smaller angle than the vertical. The first illumination portion (22) includes a first lamp (22a) that is tilted at a certain angle to the upper side and provides a light source. The light source provided by the first illumination unit (22) is preferably visible light having a wavelength of less than blue (about 495 nm or less). The reason will be explained using Fig. 2 .

Fig. 2 is a graph showing the reflectance of different light wavelengths when light is irradiated to a metal substance. The surface of the bonding lead of the light-emitting diode as the object to be inspected is generally gold-plated with gold (Au). Referring to Fig. 2, when gold (Au) is irradiated with light having a wavelength of about 200 nm to about 500 nm, the reflectance is about 40% or less. That is, if the blue wavelength light is irradiated to the gold (Au) gold-plated bonding wire, most of it is absorbed, and in the image in which the light-emitting diode is imaged, it is displayed darker than the surrounding. Therefore, the contrast between the light and the dark is clear, so that the connection state of the bonding wires can be more accurately known.

(a) of FIG. 3 shows a light-emitting diode in which the first illumination unit (22) of the conventional light-emitting diode inspection apparatus supplies the light-emitting diode as the inspection object with the light source having the green wavelength range of visible light. The image of the joint lead portion.

Referring to (a) of Fig. 3, the color difference between the gold-plated (Au) gold-plated bonding wire portion of the light-emitting diode and the light-emitting diode body portion which is the background of the bonding wire is not clear. In particular, since the color of the bonding leads in the red circles is not uniform, there is a fear that the visual processing unit (40), which will be described later, erroneously determines that the bonding leads are disconnected. This is because the visible light in the green wavelength range provided by the first illumination portion (22) is not only reflected in the body portion of the light-emitting diode, but also reflected on the surface of the bonding wire plated with gold (Au), thereby being photographed by the camera. In the image, the bonding leads are not clearly distinguished from the background portion.

(b) of FIG. 3 shows a light-emitting diode in which the light source provided by the first illumination unit of the non-contact type light-emitting diode inspection apparatus according to an embodiment of the present invention is in the visible light range of blue or lower The image of the body's bonded lead portion. The visible light having a wavelength range of blue or less is mostly absorbed on the surface of the bonding lead of the light-emitting diode made of gold (Au), and thus it can be confirmed that the image indicated by the red arrow is in the image of the light-emitting diode. The lead portion is distinct from the background portion.

In order to further increase the absorption of visible light in the blue wavelength range below the surface of the bonding lead of the light-emitting diode, the Brewster's angle principle can be utilized. Figure 4 is a conceptual diagram showing the principle of Brewster's angle. When light passes between two media with different refractive indices, reflection usually occurs at the interface (200). However, if light of a certain polarization form is incident at a specific angle of incidence, it is not reflected at the interface (200), but is refracted and transmitted through a different medium (120). At this time, the incident angle formed by the normal (202) of the interface (200) and the incident light (100) is the Brewster angle (θB).

In this angle, the electric field of the polarized light is aligned with the plane of incidence and thus does not reflect. The light in the polarized state is referred to as a horizontally polarized light or a p-polarized state, which is named because it is parallel to the plane of incidence. If the polarized light is in a state perpendicular to the plane of incidence of light, it is called a vertically polarized light or an s-polarized state, derived from the German senkrecht indicating the vertical meaning. Therefore, if the incident light (100) in the non-polarized state is incident at the Brewster angle (θB), the reflected light (110) is always in the s-polarized state.

Referring again to Fig. 1, by arranging a polarizing filter (24b) that isolates the s-polarizing component before the first illuminating portion (22), the incident light emitted from the first illuminating portion (22) is opposite to the light emitting diode ( When the surface of 5) is incident at the Brewster angle, by preventing the incident light from being reflected on the surface of the light-emitting diode (5), a more clear image of the light-emitting diode (5) can be obtained.

However, as the object to be inspected, that is, the illumination of the light-emitting diode (5), if visible light having a wavelength range of blue or less is used, as shown in (a) of FIG. 5, except for the light-emitting diode. In addition to the bonding lead portion, there is a problem that it is difficult to recognize the main body portion pattern or the like of the light emitting diode. To solve this A problem is that a second illumination portion (24) is disposed above the first illumination portion (22), and a light source that is incident perpendicularly is provided to the LED (5). The second illumination portion (24) may include a second lamp (24a) and a half mirror (24b), wherein the second lamp (24a) is located at a side of the second illumination portion (24), provided The light source, the half mirror (24b) is spaced apart from the second lamp (24a) by a distance and arranged along a diagonal line.

The light source provided by the second illumination portion (24) is preferably visible light in the green wavelength range (about 495 nm to about 570 nm). The reason is that the pattern of the light-emitting diode wafer is parallel to the bottom surface and is a mirror-like surface, so that the green light wavelength light provided by the second illumination portion (24) perpendicularly to the pattern of the wafer is positively reflected toward the camera direction. .

Further, the non-contact type light-emitting diode inspection apparatus of the present invention transmits only the wavelength range of a region narrower than the optical system of the entire visible light region by using the blue and green wavelength ranges. Therefore, the chromatic aberration is small, the design of the camera lens is relatively easy, and the lens can be produced with a low-cost material.

(b) of FIG. 5 shows visible light in the blue wavelength range and the second illumination portion provided by the first illumination portion simultaneously irradiating the light-emitting diode as the inspection target object according to an embodiment of the present invention. A light-emitting diode image obtained in the visible range of the wavelength range. (b) of FIG. 5 is comparable to (a) of FIG. 5, and it can be confirmed that the pattern image of the light-emitting diode main body portion can be obtained more vividly.

Referring again to Fig. 1, the camera (30) is positioned above the illumination unit (20) to capture an image of the LED (5). In Fig. 1, only one camera (30) is shown, but the visual inspection device of the present invention may have a plurality of cameras (not shown) having different magnifications, and variously change the light-emitting diodes according to the needs of the user ( 5) The scope of inspection. Further, a plurality of lenses (not shown) having different magnifications may be provided between the camera (30) and the illumination unit (20), and the inspection range of the light-emitting diode (5) may be variously changed.

On the other hand, the visual processing unit (40) compares the image information obtained from the camera (30) with the target image input in advance to determine whether the light-emitting diode (5) is good or bad.

The control unit (50) is a constituent element including a motion controller (not shown) that controls driving and operation of the stage unit (10) and the camera (30), and can also control the visual inspection of the present invention. The overall drive of the device.

That is, as shown in Fig. 6, the control unit (50) can transport the visual inspection device coupled to the transport conveyor (60) to the front, rear, left, and right of the fixed light-emitting diode (5). In order to transmit a shooting control signal to the camera (30) in accordance with a shooting area of the preset light-emitting diode (5).

Further, the control unit (50) not only performs physical control such as imaging position control of the visual inspection device, processing of captured video, and control of the illumination unit (20), but also performs an inspection operation and a data calculation operation in accordance with the system control program.

Further, the control unit (50) is responsible for the output device control for outputting the work content and the inspection result to the display, and is capable of inputting the overall control of the visual inspection device such as the setting and the input device control of various items. The present invention is not limited to the above embodiments and drawings, but is defined by the scope of the patent application. Therefore, various forms of substitutions, modifications, and alterations can be made without departing from the scope of the invention as described in the appended claims. It is to be understood by those skilled in the art that The technical ideas described in the scope.

According to the non-contact type light-emitting diode inspection device of the present invention, the image alignment of the respective elements of the light-emitting diode can be clearly performed, so that the bonding wire connection state and the light-emitting state inside the light-emitting diode can be more clearly obtained. Image information of the pattern of the polar body.

5‧‧‧Lighting diode

10‧‧‧The Stage Department

20‧‧‧Lighting Department

22‧‧‧First Lighting Department

22a‧‧‧First light

24‧‧‧Second Lighting Department

24a‧‧‧second light

24b‧‧‧ polarizing filter

30‧‧‧ camera

40‧‧‧Visual Processing Department

50‧‧‧Control Department

Claims (7)

A non-contact type light-emitting diode inspection device is an inspection device for determining whether a light-emitting diode is good or bad, by comparing a captured image with a target image input in advance by capturing a light-emitting diode with a camera. The non-contact light-emitting diode inspection apparatus includes a stage portion on which the light-emitting diode is mounted to fix the light-emitting diode to an inspection position or conveyance, and an illumination unit including a first illumination unit and a first illumination unit a second illumination unit, wherein the first illumination unit is located above the stage portion, and irradiates the light-emitting diode with visible light having a wavelength range of less than blue, and the second illumination unit is located above the first illumination unit. And illuminating the light-emitting diode with visible light in a green wavelength range; the camera is located above the illumination portion for capturing an image of the light-emitting diode; and the visual processing unit reads the image captured by the camera and discriminates the image a good or bad light-emitting diode; and a control portion including a motion controller that controls the stage portion and the camera portion. The non-contact light-emitting diode inspection apparatus according to claim 1, wherein the first illumination unit irradiates light to the light-emitting diode at a Brewster's angle. The non-contact LED inspection device of claim 1, further comprising a polarizing filter, the polarizing filter being located in front of the first illumination portion for isolating the first illumination portion The specific polarized light component of the emitted light. The non-contact type light emitting diode inspection apparatus according to claim 3, wherein the polarizing filter isolates an s-polarized component. The non-contact type light emitting diode inspection apparatus according to claim 1, wherein the wavelength below the blue color is 495 nm or less. The non-contact type light emitting diode inspection apparatus according to claim 1, wherein the green wavelength is 495 nm to 570 nm. The non-contact type light emitting diode inspection apparatus according to claim 1, wherein the light emitting diode includes a body portion having a bonding lead and a pattern including a gold (Au) component formed on the surface.