KR20190053360A - Led testing apparatus and method of testing led - Google Patents

Abstract

An LED inspection device inspects a base part, an LED chip on the base part, and an LED package including a film on the LED chip. The LED inspection device comprises: a light source part including a first light source for irradiating the LED package with ultraviolet light, and a second light source for irradiating light in the visible light region to the LED package; and a camera for acquiring an image of the LED package using the ultraviolet light irradiated from the first light source and the light in the visible light region irradiated from the second light source. The image is an image obtained by simultaneously using the ultraviolet light and the light in the visible light region, and inspects whether or not the LED package is defective by using the image.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED test apparatus,

The present invention relates to an LED inspection apparatus for inspecting an LED package that can be applied to a backlight, a lighting apparatus, and the like, and an LED inspection method using the LED inspection apparatus. More particularly, the present invention relates to an LED inspection apparatus capable of automatically checking whether the LED package is defective or not, and an LED inspection method using the LED inspection apparatus.

2. Description of the Related Art In general, a light emitting diode (LED) constitutes a light emitting source by changing a compound semiconductor material such as GaAs, AlGaAs, GaN, InGaInP, or the like to form a semiconductor device capable of realizing light of various colors It says.

In order to manufacture an LED package using the LED and to manufacture a product such as a display device or a lighting device using a plurality of the LED packages, it is necessary to inspect whether the LED package is defective or not.

However, when visual inspection is performed on whether or not the LED package is defective, there is a problem that the objective inspection standard among the inspectors is ambiguous and the reliability of the inspection result is deteriorated due to the difference in the detection ability between the expert and the non-expert. Accordingly, in order to automate the inspection process, it has been necessary to obtain an image clearly indicating the state of the LED package.

An object of the present invention is to provide an LED inspection apparatus capable of automatically checking whether a LED package is defective.

Another object of the present invention is to provide an LED inspection method using the LED inspection apparatus.

According to exemplary embodiments of the present invention, an LED inspection apparatus examines a base unit, an LED chip on the base unit, and an LED package including a film on the LED chip. Wherein the LED inspection apparatus includes a light source unit including a first light source for irradiating ultraviolet rays to the LED package and a second light source for irradiating light in a visible light region to the LED package, And a camera for acquiring an image of the LED package using light in a visible light region emitted from the light source. The image is an image obtained by using the light in the ultraviolet ray and the visible light region at the same time, and checks whether the LED package is defective by using the image.

According to another aspect of the present invention, there is provided a method of inspecting an LED according to exemplary embodiments of the present invention, the method comprising the steps of: simultaneously irradiating ultraviolet light and visible light onto a base, Inspect the LED package. And acquires an image of the LED chip irradiated with the ultraviolet light and the visible light. A defect is judged using the image. The image is an image obtained by simultaneously using the ultraviolet light and the light in the visible light region.

In an optical measuring method and apparatus according to exemplary embodiments, the LED testing apparatus inspects an LED package including a base portion, an LED chip on the base portion, and a film on the LED chip. Wherein the LED inspection apparatus includes a light source unit including a first light source for irradiating ultraviolet rays to the LED package and a second light source for irradiating light in a visible light region to the LED package, And a camera for acquiring an image of the LED package using light in a visible light region emitted from the light source. The image is an image obtained by using the light in the ultraviolet ray and the visible light region at the same time, and checks whether the LED package is defective by using the image.

As a result, the UV luminescence that emits ultraviolet rays generates a luminous effect of the LED chip, and the region where the film is positioned can be brightly imaged by the emitted light. In addition, Bright and clear images can be obtained for all films. The reliability of the LED inspection apparatus and method can be improved by using the image.

However, the effects of the present invention are not limited to the above-mentioned effects, and may be variously expanded without departing from the spirit and scope of the present invention.

1 is a cross-sectional view illustrating an LED inspection apparatus according to exemplary embodiments of the present invention.
2 is a plan view of the LED package 10 inspected by the LED inspection apparatus of Fig.
3 is a flow chart illustrating an LED inspection method in accordance with exemplary embodiments of the present invention.
FIG. 4 is an image of LED packages taken using normal white light.
5 is an image of LED packages using blue light.
6 is an image of an LED package using blue light and a yellow pass filter.
FIG. 7 is an image of an LED package using ultraviolet rays according to exemplary embodiments of the present invention.
8A is a view showing an x-direction gradation profile and a y-direction gradation profile of an image of an LED package taken using a general white light.
8B is a view showing an x-directional gradation profile and a y-directional gradation profile of an image of an LED package using ultraviolet ray (UV) and visible light according to exemplary embodiments of the present invention.
FIG. 9A is an image of an LED package photographed by using a sawtooth wave having a maximum peak wavelength of 400 nm. FIG.
FIG. 9B is an image of an LED package photographed using a pyramid having a maximum peak wavelength of 360 nm.
10A, 10B, 10C and 10D are images obtained using an LED inspection apparatus according to exemplary embodiments of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view illustrating an LED inspection apparatus according to exemplary embodiments of the present invention. 2 is a plan view of the LED package 10 inspected by the LED inspection apparatus of Fig.

Referring to FIGS. 1 and 2, the LED inspection apparatus may include a light source unit 100 and a camera 200. The LED inspection apparatus may further include a control unit (not shown) for controlling the light source unit 100 and the camera 200. The LED inspection apparatus may obtain an image of the LED package 10 disposed on the substrate 20 to determine a defective state.

The LED package 10 may include a base portion 12, an LED chip 14, a side wall portion 16, and a film 18.

The base portion 12 is disposed on the substrate 20, and a plurality of LED packages may be disposed on the substrate 20, though not shown in detail.

And the LED chip 14 may be mounted on the base portion 12. The LED chip 14 may be a blue light emitting diode emitting blue light. The maximum peak wavelength of the blue light emitting diode may be about 400 nm or more. For example, the maximum peak wavelength of the blue light emitting diode may be 420 nm.

The side wall portion 16 may be formed on the base portion 12 so as to surround the LED chip 14. The side wall portion 16 may be formed by titanium dioxide (TiO 2) dispensing or the like.

The film 18 may be a film that is disposed on the LED chip 14 and the side wall portion 16, and includes a transparent film or a phosphor. The film 18 and the side wall portion 16 can seal the LED chip 14. [

In general, the conventional LED package is mainly formed by bonding an LED chip in a cup-shaped package, dispensing the encapsulation material for controlling the color temperature and protecting the internal device . According to the present invention, the LED package 10 may use the film 18 instead of the sealing material, and use the sidewall 16 instead of the cup-shaped package insert to produce a bright and thin LED package.

The main function of the film 18 in the LED package 10 is to protect the LED chip 14 and to control the characteristics of light emitted by the LED chip 14 including additives such as phosphors. The state of the film 18 mounted is very important. The shift position and the rotation direction of the LED chip 14 and the film 18 coincide with each other and the light flux is transmitted between the LED chip 14 and the film 18 or on the upper surface of the film 18. [ There should be no foreign body to inhibit. If there is a problem in mounting the film 18, it is necessary not only to expose the luminous flux, the optical path, and the LED chip 14 but also to cause appearance defects, so that the process of inspecting the mounting condition of the film 18 is indispensable. The LED inspection apparatus according to the present invention can be used.

The light source unit 100 may include a first light source 110, a second light source 120, a third light source 130, and a reflective unit 150.

The first light source 110 emits an ultraviolet ray to irradiate the LED package 10 with the ultraviolet rays. The first light source 110 may be a UV lamp. The ultraviolet light emitted by the first light source 110 may have a maximum peak wavelength shorter than a maximum peak wavelength of light emitted by the LED chip 14 of the LED package 10. For example, when the LED chip 14 is a blue light emitting diode emitting blue light, the maximum peak wavelength of the ultraviolet light emitted by the first light source 110 may be about 360 nm.

The ultraviolet light generated from the first light source 110 may cause a photoluminescence effect of the LED chip 14 of the LED package 10.

The luminescent light luminescence effect refers to light generated when an excited electron receives a larger energy than a band gap of a semiconductor device and recombines the light. The LED chip 14 is also a band gap ), The LED chip 14 is excited and emits light with a photoelectric effect.

The second light source 120 emits blue light in a visible light region and can irradiate the blue light to the LED package 10. The second light source 120 may be a blue light source.

The third light source 130 may emit red light in the visible light region and may irradiate the red light to the LED package 10. The second light source 120 may be a blue light source.

The second light source 120 and the third light source 130 may be a light source for identifying a configuration other than the film 14 of the LED package 10. If only the first light source 110 is used, the other area of the LED package 10 except for the film 18 appears black, so that the position of the film 18 is shifted or rotated Can not check. Therefore, it is necessary to further illuminate visible light so that the outermost portion of the LED package 10 can be seen. In addition to the inspection of the film 18, in addition to the inspection of defective items (foreign objects, cracks, etc.) The second light source 120, and the third light source 130 may be further combined.

The reflector 150 reflects light generated by the first, second, third, and fourth light sources 110, 120, and 130 to the LED package 10 to improve light efficiency.

The camera 200 may acquire an image of the LED package using ultraviolet rays emitted from the first light source 110 and blue and red lights emitted from the second and third light sources 120 and 130. The camera 200 can acquire a plane image of the LED package 10 so that the outer surface of the base 12 and the outer periphery of the film 18, It is possible to acquire the image that can identify the outline of the image 14.

The control unit may determine whether the LED package 10 is defective by using the image obtained from the camera 200. The controller identifies the outer periphery of the base portion 12 of the LED package 10, the outer periphery of the film 18 and the outer periphery of the LED chip 14 using various conventionally known image determination methods, It is possible to determine whether or not the LED package 10 is defective by determining the position of the outer periphery of the LED chip 14 and the rotation of the outer periphery of the base 12, the outer periphery of the film 18, and the like.

3 is a flow chart illustrating an LED inspection method in accordance with exemplary embodiments of the present invention.

Referring to FIGS. 1 and 3, the LED inspection method may be performed using the LED inspection apparatus. The LED inspection method may include a light irradiation step (S100), an image acquisition step (S200), and a failure determination step (S300).

In the light irradiation step S100, the first and second light sources 110 and 120 of the LED inspection apparatus are used to irradiate the LED package 10 with ultraviolet rays and visible rays (Blue light and red light).

In the image acquiring step S200, an image of the LED package 10 in a state irradiated with the ultraviolet light and the visible light may be acquired. Accordingly, as shown in FIG. 2, it is possible to obtain the image that can identify the outer edge of the base 12, the outer edge of the film 18, and the outer edge of the LED chip 14.

In the defect determination step S300, it is possible to determine whether the LED package 10 is defective by analyzing the image using the image. For example, when the position of the film 18 is out of the predetermined position (shift and rotation), deviation of the LED chip 14, infiltration of material constituting the side wall portion, can do. The method of analyzing the image may be various conventional methods known in the art for analyzing images using a computer.

According to the present embodiment, since the image can obtain a clear image compared to the conventional technology (see FIGS. 7 and 8B), the image calculation process to be processed in the defect determination of the LED package 10 is simplified, The accuracy of the result can be improved. Thus, the inspection of the defectiveness of the LED package 10 can be automated, and the reliability of the result can be improved.

FIG. 4 is an image of LED packages taken using normal white light. 5 is an image of LED packages using blue light. 6 is an image of an LED package using blue light and a yellow pass filter. FIG. 7 is an image of an LED package using ultraviolet rays according to exemplary embodiments of the present invention.

Generally, it is difficult to obtain an effective image for an automatic inspection process with visible light. In particular, when the film 18 of the LED package 10 is transparent without any special color, it is difficult to obtain a clear image because the transparent material is transmitted through the illumination light.

In Figs. 4 to 7, it is possible to confirm the image difference for each illumination type, with respect to the film A containing the phosphor and the film B not including the phosphor.

Referring to FIG. 4, in the white light illumination representing the visible light wavelength, it is difficult to recognize the boundaries of both the film (A) and the film (B).

Referring to FIG. 5, it can be confirmed that the phosphor added to the film (A) is excited by the blue light to become bright, though it is a visible light blue light illumination.

Referring to FIG. 6, an image suitable for film inspection can be obtained by using an optical filter (here, Yellow Pass Filter) under the condition of FIG. However, this is only possible with the film (A) containing the phosphor, and the transparent film (B) has no effect.

Referring to FIG. 7, according to the present invention, a UV light emitting ultraviolet light generates a photo-luminescence effect of an LED chip, and a region where the film is located can be brightly imaged by the emitted light . As can be seen from the image, a bright and clear image was obtained for both the film (A) containing the phosphor and the film (B) for the phosphor.

8A is a view showing an x-direction gradation profile and a y-direction gradation profile of an image of an LED package taken using a general white light. 8B is a view showing an x-directional gradation profile and a y-directional gradation profile of an image of an LED package using ultraviolet ray (UV) and visible light according to exemplary embodiments of the present invention.

Imaging an object to be inspected greatly affects the inspection result and process. As the image is clear and the characteristic (contrast or color difference) of good / poor is clear, the image calculation process Simplifies and improves the accuracy of the results. Therefore, much effort is being devoted to obtaining images suitable for inspection, and the availability of automation depends on the state of the acquired image.

Referring to FIG. 8A, it can be seen that the boundaries of the respective components do not appear clearly in the x-direction gradation profile and the y-direction gradation profile of the image of the LED package using general white light.

Referring to FIG. 8B, according to the present invention, an image of an LED package photographed using ultraviolet (UV) rays and visible light is used to determine a boundary of each configuration, specifically, an x- It can be seen that the boundary of the film can be clearly recognized.

FIG. 9A is an image of an LED package photographed by using a sawtooth wave having a maximum peak wavelength of 400 nm. FIG. FIG. 9B is an image of an LED package photographed using a pyramid having a maximum peak wavelength of 360 nm.

Referring to Figures 1, 9a and 9b, the illumination wavelengths that produce the photoluminescence effect vary from object to object. In the case of the LED chip 14, it is necessary to use a wavelength in a region having a higher energy than an emission wavelength, and there is a specific region that responds to the characteristics of the LED chip 14.

In the case where the LED chip 14 is a blue LED, when an illumination that emits ultraviolet rays having a peak wavelength of 360 nm is used (FIG. 9B), when the illumination with a peak wavelength of 400 nm is used (FIG. 9A) We could obtain more clear images with good effect. It is important to select the wavelength of the light source.

10A, 10B, 10C and 10D are images obtained using an LED inspection apparatus according to exemplary embodiments of the present invention.

Referring to Figures 2 and 10a, 10b, 10c and 10d, the images are shown as defective rotations in which the film 18 of the LED package 10 and the LED chip 14 are rotated in position, the film 18 ) And defective TiO 2 penetration due to penetration of the titanium dioxide forming the side wall portion (refer to 16 in FIG. 1) toward the LED chip 14, the film 18 ) Is out of the correct position and is a chip-film detachment failure that does not cover the LED chip 14. [ The image appears relatively clearly at the outer periphery of the base portion 12, the outer edge of the film 18, and the outer periphery of the LED chip 14 at the portion where the film 18 and the LED chip 14 overlap. This is because ultraviolet rays generated in the LED inspection device excite the LED chip 14 and then the film 18 appears bright using light emitted from the LED chip. Therefore, Even if there is no clear image can be obtained. In addition, the LED package 10 can be visually confirmed with the visible light.

The images shown in FIGS. 10A, 10B, 10C, and 10D are images obtained using the LED inspection apparatus of the present invention. By obtaining an improved image of the transparent film, it was possible to apply automatic inspection such as film shift, rotation, chip-film deviation, and TiO2 penetration, which had previously been difficult to apply, to the process.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the following claims. It can be understood that it is possible.

100: light source 110: first light source
120: second light source 130: third light source
150: reflector 200: camera
10: LED package 12: base part
14: LED chip 16: side wall portion
18: Film 20: Substrate

Claims (10)

An LED inspection apparatus for inspecting an LED package including a base portion, an LED chip on the base portion, and a film on the LED chip,
A light source unit including a first light source for irradiating ultraviolet rays to the LED package and a second light source for irradiating light in a visible light region to the LED package; And
And a camera for acquiring an image of the LED package using ultraviolet light emitted from the first light source and light in a visible light region emitted from the second light source,
Wherein the image is an image obtained by simultaneously using the ultraviolet light and the light in the visible light region, and inspects whether the LED package is defective by using the image. The method according to claim 1,
The LED of the LED package is a light emitting diode (LED) emitting blue light,
Wherein the first light source emits ultraviolet rays having a peak wavelength of 360 nm. 3. The method of claim 2,
Further comprising a third light source,
Wherein the second light source emits blue light, and the third light source emits red light. The method according to claim 1,
The image is relatively clear on the outer periphery of the base portion, the outer periphery of the film, and the outer edge of the LED chip in a portion where the film and the LED chip overlap each other, and determines whether the LED package is defective or not, LED inspection device. Irradiating ultraviolet light and visible light to an LED package including a base portion, an LED chip disposed on the base portion and a film on the LED chip at the same time;
Obtaining an image of the LED chip irradiated with the ultraviolet light and the visible light;
And judging a defect using the image,
Wherein the image is obtained by simultaneously using the ultraviolet light and the light in the visible light region. 6. The method of claim 5,
Wherein the ultraviolet light causes the optical luminescence effect of the LED and the film is brightened by the light emitted from the LED by the luminescence effect and the portion of the overlapping portion of the LED and the film Wherein the outer shape of the LED and the outer shape of the film are relatively clear. The method according to claim 6,
The LED of the LED package is a light emitting diode (LED) emitting blue light,
And the ultraviolet ray has a peak wavelength of 360 nm. 8. The method of claim 7,
Wherein the visible light is blue light and red light. 6. The method of claim 5,
Wherein the LED package further comprises a side wall portion disposed between the base substrate and the film and including titanium dioxide surrounding the LED chip,
In the step of judging the defect,
The rotation of the film and the LED chip in a predetermined position is defective, the film and the shift of the LED chip are shifted in a proper position, the titanium dioxide constituting the side wall portion penetrates into the LED chip Determining whether the film is defective in TiO2 penetration and whether the film is defective in chip-film detachment that does not cover the LED chip when the film is out of the correct position. 6. The method of claim 5,
Wherein the film of the LED package does not include a phosphor.

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