KR20110077098A - Apparatus and method of inspecting leds - Google Patents

Abstract

PURPOSE: An apparatus and a method for inspecting a light emitting diode is provided to check whether or not the light emitting diode has a poor phosphor layer. CONSTITUTION: An apparatus for inspecting a light emitting diode includes an irradiation portion(130), an image acquisition part(140), and a determining unit(150). The irradiation portion irradiates ultraviolet ray to a light emitting diode having a phosphor material layer. The image acquisition part detects the visible ray emitted due to the ultraviolet ray from the fluorescent material layer. The image acquisition part acquires an image of the light emitting diode. The determining unit determines whether or not the light emitting diode is poor using the image.

Description

Apparatus and method of inspecting LEDs

The present invention relates to a light emitting diode inspection device and method, and more particularly to a light emitting diode inspection device and method for inspecting the abnormality of the fluorescent material layer of the light emitting diode.

Light Emitting Diodes (LEDs) have recently been improved in light emission efficiency, and their application ranges from early signal displays such as backlight units (BLUs) and liquid crystal displays (LCDs) for mobile phones. It is becoming wider for light sources and lighting of large display devices. The reason for this is that the light emitting diode consumes less power and has a longer life than conventional light bulbs and fluorescent lamps.

The light emitting diode includes a lead frame, a light emitting diode chip attached to the lead frame, a wire connecting the chip and the lead frame, and a fluorescent material layer provided on the chip.

The inspection of the light emitting diode is performed by obtaining an image to the light emitting diode using visible light as a light source and using the obtained image.

 However, in the image obtained by using the visible light as a light source, the fluorescent material layer is almost transparent. Since the fluorescent material layer is not distinguished in the image, it is difficult to accurately determine the size of the fluorescent material layer. In addition, it is difficult to distinguish the wire located under the fluorescent material layer from the foreign material located on the fluorescent material layer in the image. Therefore, it is difficult to determine whether the light emitting diode is defective.

The present invention provides a light emitting diode inspection device for identifying a failure of a light emitting diode having a fluorescent material layer.

The present invention provides a light emitting diode inspection method for identifying a defect of a light emitting diode having a fluorescent material layer.

An LED inspection apparatus according to the present invention includes an irradiation unit for irradiating ultraviolet rays with a light emitting diode having a fluorescent material layer, and an image obtaining unit for detecting an image of visible light emitted from the fluorescent substance due to the ultraviolet rays. And a determination unit to determine whether the light emitting diode is defective using the image.

According to one embodiment of the present invention, the image acquisition unit is disposed above the light emitting diode vertically and the first acquisition unit for detecting visible light emitted from the fluorescent material and disposed above one side of the light emitting diode and the fluorescence And a second acquirer configured to detect visible light emitted from the material, wherein the image acquirer may acquire two light emitting diode images or a three-dimensional light emitting diode image.

According to one embodiment of the present invention, the LED inspection apparatus includes a support for supporting the LED or the LED array consisting of the LED and the support for the ultraviolet ray to scan the LED or the LED array. The driving unit may further include a moving unit.

According to one embodiment of the present invention, when the size of the fluorescent material layer of the image is smaller or larger than a predetermined reference size, the determination unit may determine the light emitting diode as defective.

According to one embodiment of the present invention, when the foreign material is located on the fluorescent material layer of the image, the determination unit may determine the light emitting diode as bad.

The light emitting diode inspection method according to the present invention comprises the steps of irradiating ultraviolet light with a light emitting diode having a fluorescent material layer, detecting the visible light emitted from the fluorescent material layer due to the ultraviolet light, and using the detected visible light The method may include obtaining an image of the light emitting diode and determining whether the fluorescent material layer is defective by using the obtained image.

According to one embodiment of the present invention, the detecting of the visible light may include detecting visible light emitted vertically upward from the fluorescent material and visible light emitted upward from one side of the fluorescent material, respectively, Acquiring an image may acquire two light emitting diode images or a three-dimensional light emitting diode image.

According to one embodiment of the present invention, the light emitting diode inspection method may further include moving the light emitting diode so that the ultraviolet ray scans the light emitting diode.

According to one embodiment of the present invention, when the size of the fluorescent material layer of the image is smaller or larger than the reference size, it may be determined that the light emitting diode is defective.

According to one embodiment of the present invention, when a foreign material is located on the fluorescent material layer of the image, the light emitting diode may be determined as defective.

The LED inspection apparatus and method according to the present invention obtains an image of the LED using visible light emitted from the fluorescent material layer in response to the irradiated ultraviolet rays. The image is clear because the fluorescent material layer emits light, and the wire under the fluorescent material layer is hardly visible. Since the shape of the fluorescent material layer is correctly identified, the size of the fluorescent material layer can be easily confirmed. In addition, since the wire is almost invisible, foreign matters can be easily identified in the image.

Hereinafter, a light emitting diode inspection apparatus and method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

1 is a schematic block diagram illustrating a light emitting diode inspection apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the LED inspection apparatus 100 includes a support 110 supporting the light emitting diode 10, a driver 120 for moving the support 110, and ultraviolet rays to the light emitting diode 10. Irradiation unit 130 for irradiating the light, the image acquisition unit 140 for obtaining an image of the light emitting diode 10 by detecting the visible light emitted from the light emitting diode 10, the light emitting diode 10 using the image Determination unit 150 to determine whether or not the abnormality and a display unit 160 for displaying the generated image.

The support part 110 supports the light emitting diode 10 in a horizontal state. For example, the support 110 may support one light emitting diode 10. As another example, the support 110 may support a light emitting diode array including a plurality of light emitting diodes 10. The support 110 has a flat plate shape.

The light emitting diode 10 includes a lead frame, a light emitting diode chip attached to the lead frame, a wire connecting the chip and the lead frame, and a fluorescent material layer provided on the chip.

The driving part 120 is connected to the support part 110 and moves the support part 110 in the horizontal direction. The driving unit 120 may move the support 110 in a vertical direction perpendicular to the horizontal direction. Examples of the driving unit 120 may include a linear motor, a cylinder, and the like.

The irradiator 130 is disposed above the support 110 and irradiates ultraviolet light toward the light emitting diode 10. The irradiator 130 includes a light source that emits ultraviolet rays. Examples of the light source include an ultraviolet laser, a UV LED, a xenon arc lamp, a mercury arc lamp, and a xenon mercury arc lamp.

After moving the support 110 supporting the light emitting diode 10, the irradiation unit 130 may irradiate the ultraviolet light to selectively irradiate the ultraviolet light only to the light emitting diode 10 in a desired region. In addition, the irradiation unit 130 irradiates the ultraviolet light while moving the support 110 supporting the light emitting diode 10, thereby irradiating the ultraviolet light to the light emitting diode 10 in the entire region.

The reason for irradiating the ultraviolet light to the light emitting diode 10 is to use the fluorescence generating principle. Specifically, when the ultraviolet light is irradiated onto the light emitting diode 10, electrons of the fluorescent material layer in a ground state are in an excited state due to the energy of the ultraviolet light. The electrons do not continue to be in an excited state, and some energy is lost to the ground state again. The fluorescent material layer emits light due to the energy generated when the electrons in the excited state return to the ground state. In this case, the light becomes a visible light having a wavelength lower than that of the ultraviolet light, that is, the wavelength is longer due to the loss of some energy.

The image acquisition unit 140 is disposed above the support unit 110 to be adjacent to the irradiation unit 130, and detects visible light emitted from the light emitting diode 10 to display an image of the light emitting diode 10. Acquire. For example, the image acquisition unit 140 detects visible light emitted from the fluorescent material layer of the light emitting diode 10 due to the ultraviolet irradiation. Thereafter, the image acquisition unit 140 converts the visible light into electric charges to obtain an image of the light emitting diode 10.

The image acquirer 140 includes a first acquirer 142 and a second acquirer 144.

The first acquirer 142 is disposed above the support 110, and detects visible light emitted vertically upward from the light emitting diode 10 to obtain an image of the light emitting diode 10.

The second acquisition unit 144 is disposed above one side of the support unit 110 and is emitted to be inclined from the light emitting diode 10 toward the one side upward, that is, to be inclined from the light emitting diode 10. Visible light is detected to obtain an image of the light emitting diode 10.

Since the first acquirer 142 and the second acquirer 144 acquire images, respectively, the image acquirer 140 acquires two images of the light emitting diode 10 or the two images. By using to obtain a three-dimensional image of the light emitting diode (10).

2A and 2B are photographs illustrating images acquired by the image acquisition unit of FIG. 1.

Referring to FIG. 2A, the image is an upper image of the light emitting diode 10 acquired by the first acquirer 142.

Referring to FIG. 2B, the image is a side image of the light emitting diode 10 obtained by the second acquirer 144.

The defect of the light emitting diode 10 may be confirmed more accurately by using the top image and the side image of the light emitting diode 10.

Referring back to FIG. 1, the determination unit 150 is connected to the image acquisition unit 140 and determines whether the light emitting diode 10 is defective using the image acquired by the image acquisition unit 140. do. The determination unit 150 may determine whether the light emitting diode 10 is defective by comparing the image with a reference image in a normal state.

Examples of the defect of the light emitting diode 10 may include a poor size of the fluorescent material layer, the presence of the foreign matter, a poor contact of the wire, and the like. The size defect of the fluorescent material layer refers to a case in which the size of the fluorescent material layer is smaller or larger than a reference size. The presence of the foreign matter refers to a case where the foreign matter is fixed on the fluorescent material layer. The poor contact of the wires refers to a case in which the wires are spaced apart without contacting the chip or the lead frame.

For example, when the fluorescent material layer size of the image is the same as the fluorescent material layer size of the reference image within the error range, the determination unit 150 determines the light emitting diode 10 as normal. When the size of the fluorescent material layer of the image is smaller or larger than the size and the error range of the fluorescent material layer of the reference image, the determination unit 150 determines the light emitting diode 10 as defective.

As another example, when the foreign matter does not exist on the fluorescent material layer, the determination unit 150 determines the light emitting diode 10 as normal. When the foreign matter is present on the fluorescent material layer, the foreign matter may adversely affect the brightness of the light emitting diode 10, and the determination unit 150 determines the light emitting diode 10 as defective. .

As another example, when the wire is in contact with the chip or the lead frame, the determination unit 150 determines the light emitting diode 10 as normal. When the wire is spaced apart without contacting the chip or the lead frame, the determination unit 150 determines the light emitting diode 10 as defective.

Since the ultraviolet light has a higher energy than visible light, an image generated by irradiating the ultraviolet light is clearer than an image generated by irradiating the visible light. Therefore, whether the light emitting diode 10 is defective can be easily determined. In particular, since the shape of the fluorescent material layer is correctly identified in the image, the size of the fluorescent material layer can be easily confirmed. In addition, since the wire covered by the fluorescent material layer is not visible, only the foreign material present on the fluorescent material layer can be easily identified without the need to distinguish the wire from the foreign material.

In addition, when the two light emitting diodes 10 images or the three-dimensional images of the light emitting diodes 10 are used, more information about the light emitting diodes 10 may be obtained than when the two light emitting diodes 10 are one-dimensional images. . Therefore, since it is possible to more accurately determine whether the light emitting diode 10 is defective, the inspection accuracy of the light emitting diode 10 can be improved.

The display unit 160 is connected to the image acquisition unit 140 and displays an image acquired by the image acquisition unit 140. In addition, the display unit 160 may be connected to the determination unit 150 and display the determination result of the determination unit 150. For example, the display unit 160 may display a defective portion on the determination unit 150.

The light emitting diode inspection apparatus 100 may obtain a clear image of the light emitting diode 10 by using the ultraviolet light as a light source, and obtain two images of the light emitting diode 10 or obtain a three-dimensional image. Therefore, it is possible to easily and accurately determine whether the light emitting diode 10 is defective, such as a poor size of the fluorescent material, the presence of a foreign material, and a poor contact of a wire.

3 is a flowchart illustrating a light emitting diode inspection method according to an embodiment of the present invention.

Referring to FIG. 3, ultraviolet rays are irradiated toward the light emitting diodes (S110).

Examples of the ultraviolet light source include an ultraviolet laser, an ultraviolet light emitting diode, a xenon arc lamp, a mercury arc lamp, and a xenon mercury arc lamp.

For example, the ultraviolet light may be irradiated toward one light emitting diode. As another example, the ultraviolet light may be irradiated toward a light emitting diode array including a plurality of light emitting diodes.

After moving the light emitting diode, the ultraviolet light may be irradiated to selectively irradiate the ultraviolet light only to a light emitting diode in a desired region. In addition, the ultraviolet light may be irradiated to the light emitting diode of the entire region by moving the ultraviolet light while moving the light emitting diode.

The light emitting diode includes a lead frame, a light emitting diode chip attached to the lead frame, a wire connecting the chip and the lead frame, and a fluorescent material layer provided on the chip.

When the ultraviolet light is irradiated onto the light emitting diode, electrons of the fluorescent material layer in the ground state are excited by the energy of the ultraviolet light. The electrons do not continue to be in an excited state, and some energy is lost to the ground state again. The fluorescent material layer emits light due to the energy generated when the electrons in the excited state return to the ground state. In this case, the light becomes a visible light having a wavelength lower than that of the ultraviolet light, that is, the wavelength is longer due to the loss of some energy.

When the visible light is emitted from the fluorescent material layer of the light emitting diode by the ultraviolet rays, the emitted visible light is detected (S120).

The visible light is emitted vertically above the light emitting diode and above one side of the light emitting diode, that is, in a direction inclined from the light emitting diode. Therefore, the visible light emitted vertically above the light emitting diode and the visible light emitted above the one side, that is, in the oblique direction, can be detected from the light emitting diode.

Thereafter, the visible light is converted into a charge to obtain an image of the light emitting diode (S130).

Since a light emitting diode image is obtained using the visible light emitted vertically upward and the visible light emitted in the oblique direction, the image of the light emitting diode may be two or three-dimensional.

Next, it is determined whether the light emitting diode is defective using the obtained image (S140).

For example, determining whether the light emitting diode is defective may be performed by comparing the image with a reference image in a normal state.

Examples of the defect of the light emitting diode may include a poor size of the fluorescent material layer, the presence of the foreign matter, a poor contact of the wire, and the like. The size defect of the fluorescent material layer refers to a case in which the size of the fluorescent material layer is smaller or larger than a reference size. The presence of the foreign matter refers to a case where the foreign matter is fixed on the fluorescent material layer. The poor contact of the wires refers to a case in which the wires are spaced apart without contacting the chip or the lead frame.

As an example, when the fluorescent material layer size of the image is the same as the fluorescent material layer size of the reference image within the error range, the light emitting diode is determined to be normal. If the fluorescent material layer size of the image is small or large outside the fluorescent material layer size and the error range of the reference image, the light emitting diode is determined to be defective.

As another example, when the foreign matter does not exist on the fluorescent material layer, the light emitting diode is determined to be normal. When the foreign matter is present on the fluorescent material layer, the foreign matter may adversely affect the brightness of the light emitting diode, so the light emitting diode is determined to be defective.

As another example, when the wire is in contact with the chip or the lead frame, the determination unit 150 determines the light emitting diode 10 as normal. When the wire is spaced apart without contacting the chip or the lead frame, the determination unit 150 determines the light emitting diode 10 as defective.

Next, an image of the obtained light emitting diode and a failure determination result of the light emitting diode may be displayed (S150).

For example, the image of the light emitting diode may be displayed in three dimensions, and the defective portion may be displayed as a result of the defect determination.

Since the ultraviolet light has a higher energy than visible light, an image generated by irradiating the ultraviolet light is clearer than an image generated by irradiating the visible light. Therefore, it is easy to determine whether the light emitting diode is defective. In particular, since the shape of the fluorescent material layer is correctly identified in the image, the size state of the fluorescent material layer can be easily confirmed. In addition, since the wire covered by the fluorescent material layer is not visible, only the foreign material present on the fluorescent material layer can be easily identified without the need to distinguish the wire from the foreign material.

In addition, when the two light emitting diode images or the three-dimensional image of the light emitting diodes are used, more information on the light emitting diodes may be obtained than when the two light emitting diode images are one two-dimensional images. Therefore, it is possible to more accurately determine whether the light emitting diode is defective, thereby improving inspection accuracy of the light emitting diode.

4A and 4B are photographs showing normal images acquired by using visible light as a light source and normal images obtained by using ultraviolet light as a light source.

Referring to FIG. 4A, since the fluorescent material layer A appears translucent in the image, it may be difficult to identify the size of the fluorescent material layer A since the fluorescent material layer A is not distinguished. In addition, since the fluorescent material layer (A) is translucent, it can be seen that the wire (A) located below the fluorescent material layer (A) is well visible in the image.

Referring to FIG. 4B, since the fluorescent material layer C emits light due to ultraviolet rays in the image, the fluorescent material layer C may be clear and thus the size of the fluorescent material layer C may be accurately identified. In addition, as the fluorescent material layer C emits light, the wires positioned below the fluorescent material layer C may be barely exposed in the image.

5A to 5B are photographs showing a bad image obtained by using visible light as a light source and a bad image obtained by using ultraviolet light as a light source.

Referring to FIG. 5A, since the shape of the fluorescent material layer A is not distinguished from the image, it may be difficult to determine whether the fluorescent material layer A is normal or bad.

Referring to FIG. 5B, it may be confirmed that the fluorescent material layer C is excessively large in the image so that the fluorescent material layer C is defective.

6A to 6B are photographs illustrating a bad image obtained by using visible light as a light source and a bad image obtained by using ultraviolet light as a light source.

Referring to FIG. 6A, since the shape of the fluorescent material layer A is not distinguished from the image, it may be difficult to determine whether the fluorescent material layer A is normal or bad.

Referring to FIG. 6B, the fluorescent material layer C may be excessively small in the image, and it may be confirmed that the fluorescent material layer C is defective.

7A to 7B are photographs showing a bad image obtained by using visible light as a light source and a bad image obtained by using ultraviolet light as a light source.

Referring to FIG. 7A, it may be difficult to distinguish the wire B located below the fluorescent material layer A and the foreign material D located on the fluorescent material layer A in the image. have. Therefore, it is difficult to determine whether the light emitting diode is defective.

Referring to FIG. 7B, since the wire located below the fluorescent material layer C is hardly revealed in the image, only the foreign material E located above the fluorescent material layer C is clearly visible. It can be seen that (E) can be clearly distinguished. Therefore, it is easy to check whether the light emitting diode is defective.

Referring to FIGS. 4A to 7B, when the ultraviolet light is used, the fluorescent material layer may obtain an image of a light emitting diode having a clear light emitting layer, rather than the case of using the visible light as a light source. It may be easier to determine whether the light emitting diode is defective.

The LED inspection apparatus and method according to the present invention obtains an image of the LED using visible light emitted from the fluorescent material layer in response to the irradiated ultraviolet rays. The image is clear because the fluorescent material layer emits light, and the wire under the fluorescent material layer is hardly visible. Since the shape of the fluorescent material layer is correctly identified, the size of the fluorescent material layer can be easily confirmed. In addition, since the wire is almost invisible, foreign matters can be easily identified in the image.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

1 is a schematic block diagram illustrating a light emitting diode inspection apparatus according to an embodiment of the present invention.

2A and 2B are photographs illustrating images acquired by the image acquisition unit of FIG. 1.

3 is a flowchart illustrating a light emitting diode inspection method according to an embodiment of the present invention.

4A to 7B are photographs showing images obtained by using visible light as a light source and images obtained by using ultraviolet light as a light source.

<Explanation of symbols on main parts of the invention>

100: light emitting diode inspection device 110: support

120: drive unit 130; Investigation

140: image acquisition unit 150: determination unit

160: display unit 10: light emitting diode

Claims (10)

Irradiation unit for irradiating ultraviolet light with a light emitting diode having a fluorescent material layer; An image obtaining unit which detects visible light emitted from the fluorescent material due to the ultraviolet light and obtains an image of the light emitting diode; And And a determination unit to determine whether the light emitting diode is defective using the image. The display apparatus of claim 1, wherein the image acquisition unit comprises: a first acquisition unit disposed vertically above the light emitting diode to detect visible light emitted from the fluorescent material; And A second acquisition unit disposed above one side of the light emitting diode to detect visible light emitted from the fluorescent material; The image acquiring unit acquires two light emitting diode images or a three-dimensional light emitting diode image. According to claim 1, Support portion for supporting the light emitting diode array consisting of the light emitting diode or the light emitting diode; And And a driving unit to move the support so that the ultraviolet rays scan the light emitting diode or the light emitting diode array. The apparatus of claim 1, wherein when the size of the fluorescent material layer of the image is smaller or larger than a predetermined reference size, the determination unit determines the light emitting diode as defective. The device of claim 1, wherein when the foreign material is located on the fluorescent material layer of the image, the determination unit determines that the light emitting diode is defective. Irradiating ultraviolet light with a light emitting diode having a layer of fluorescent material; Detecting visible light emitted from the fluorescent material layer due to the ultraviolet light; Acquiring an image of the light emitting diode using the detected visible light; And determining whether the fluorescent material layer is defective by using the acquired image. The method of claim 6, wherein the detecting of the visible light comprises: detecting visible light emitted vertically upward from the fluorescent material and visible light emitted upward from one side of the fluorescent material; The acquiring an image of the light emitting diode may include obtaining two light emitting diode images or a three-dimensional light emitting diode image. 7. The method of claim 6, further comprising moving the light emitting diode such that the ultraviolet light scans the light emitting diode. The method of claim 6, wherein when the size of the fluorescent material layer of the image is smaller or larger than a reference size, the light emitting diode is determined to be defective. The method of claim 6, wherein when the foreign material is located on the fluorescent material layer of the image, the light emitting diode is determined to be defective.

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