LED inspection device and LED manufacturing device, and LED inspection method and LED manufacturing method

Abstract

To accurately inspect the state of filler in individual LEDs in a stage in which the plurality of LEDs is connected to each other.SOLUTION: An LED 1 has: an LED chip 2 that is arranged on a top face of a base 7; and filler 6 that includes a fluorescent agent that is excited by light emitted from the LED chip and emits fluorescent light, and is provided on the top face of the base 7 to seal the LED chip 2. In an inspection of the LED 1, light capable of exciting the fluorescent agent is radiated toward the filler 6 from above the filler 6, the image of the light emitted from the LED 1 is picked up with the light, and finally the quality of the filler 6 is determined on the basis of the image acquired by the imaging. The radiation of the light toward the filler 6 is performed while preventing the light incident on the filler 6 from being radiated on the top face of the base 7. Consequently, the filler 6 can be accurately inspected even in a stage in which the plurality of LEDs 1 is connected to each other by a lead frame 4.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to the inspection of LEDs that have a light-emitting LED chip and a filler that fluoresces when exposed to light from the LED chip. [Background technology]

[0002] There is an LED that has an LED (Light Emitting Diode) chip capable of emitting a predetermined light and a filler containing a fluorescent agent arranged to seal the LED chip, and can generate, for example, white light by receiving the light generated by the LED chip with the fluorescent agent. As an LED capable of generating white light, there is a type that generates white light by mixing blue light generated by the LED chip with yellow light generated by the fluorescent agent by receiving the blue light from the LED chip. Also, an LED capable of generating white light is known that is configured so that red, blue, and green light are emitted from the fluorescent agent by ultraviolet light generated by the LED chip.

[0003] The LEDs described above are generally constructed by filling the LED chip (for example, around the LED chip) with a filler made of a transparent resin with dispersed fluorescent material, and sealing the LED chip with the filler. In the LED manufacturing process, multiple LEDs may be connected in parallel using a lead frame or the like. The multiple connected LEDs are finally separated as necessary.

[0004] However, if there is a problem with the filler, such as an overfill or underfill, the LED may not emit light properly. For this reason, inspections of the filler condition are sometimes carried out during the LED manufacturing process.

[0005] Here, as an inspection device for inspecting the condition of the filler, one has been proposed that measures the chromaticity and brightness of the emitted color while emitting light from an LED, and performs inspection based on the measured chromaticity, etc. (For example, see Patent Document 1, etc.) Also proposed is an apparatus that performs inspection by simultaneously lighting multiple connected LEDs and determining whether the light intensity and color temperature are appropriate (for example, see Patent Document 2, etc.).

[0006] Incidentally, the inspection devices according to the above Patent Documents 1 and 2 each perform inspection by emitting light from the LED chip. However, in a configuration in which multiple LEDs are connected, each LED chip cannot be made to emit light individually. In addition, it is difficult to control the current flowing through each LED chip when the LED chip is made to emit light, and differences in luminance when each LED chip emits light may occur due to differences in current. Therefore, in the inspection devices according to the above Patent Documents 1 and 2, it is difficult to properly inspect the state of the filler for each LED at the stage in which multiple LEDs are connected.

[0007] In response to this, a device has been proposed that inspects fillers by irradiating light from a lighting device onto an LED (filler) and measuring the intensity of light from the filler (phosphor) excited by this light, rather than making an LED chip emit light (see, for example, Patent Document 3, etc.). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2013-229621 A [Patent Document 2] JP 2012-28686 A [Patent Document 3] JP 2012-160594 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the case of an LED in which an LED chip and a filler are arranged on the upper surface of a base (for example, the package part in the above Patent Document 3) that constitutes the foundation of the LED, when light is irradiated from a lighting device to the LED (filler), the irradiated light may be strongly reflected by the upper surface of the base. Therefore, the intensity of the measured light does not depend on the state of the filler, and as a result, there is a risk that the state of the filler cannot be inspected with high accuracy.

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide an LED inspection device, etc., that can accurately inspect the condition of the filler in each LED at the stage when multiple LEDs are connected. [Means for solving the problem]

[0011] The following describes each of the means suitable for achieving the above object. Note that, as necessary, the specific effects of the corresponding means will be added.

[0012] Means 1. An LED inspection device for inspecting a filler in an LED when a plurality of LEDs each having an LED chip arranged on the upper surface of a predetermined base and a filler that contains a fluorescent agent capable of being excited by light emitted by the LED chip to emit fluorescence and is arranged on the upper surface of the base to seal the LED chip, are connected by a conductive lead frame, the device comprising: an irradiation means for irradiating the filler with light capable of exciting the fluorescent agent contained in the filler from above the filler toward the filler; an imaging means for imaging light emitted by the LED in response to light irradiated from the irradiating means; a determination means for determining whether the filler is good or bad based on the image acquired by the imaging means, The LED inspection device is characterized in that the irradiation means is configured to irradiate light from the side of the LED toward the filler so that the light incident on the filler is at an incident angle such that the light does not irradiate the top surface of the base of the LED.

[0013] According to the above-mentioned means 1, the irradiation means irradiates light from the side of the LED toward the filler so that the light incident on the filler does not directly illuminate the top surface of the base (particularly the part of the base that overlaps with the filler when viewed in plan). Therefore, it is possible to more reliably prevent the influence of reflected light from the top surface of the base, and thus to obtain an image that more clearly shows the state of the filler. This allows the state of the filler (for example, the amount of filler) to be inspected with high accuracy.

[0014] In addition, during the inspection, the LEDs are not illuminated by the light emitted from the LED chip, but by the light irradiated from the irradiating means, so that even when multiple LEDs are connected, the condition of the filler in each LED can be inspected with high accuracy.

[0015] Means 2. The imaging means acquires a luminance image having information related to luminance as the image, The LED inspection device described in means 1 is characterized in that the judgment means is configured to obtain a binary image by performing a binarization process on the luminance image using a predetermined binarization threshold, and to judge the filler to be a non-defective product if the area of ​​a connected component of a bright part in the binary image is equal to or greater than a predetermined area threshold, or if the connected component has a predetermined shape.

[0016] According to the above-mentioned means 2, the filler can be inspected with high accuracy without excessively increasing the processing load.

[0017] Means 3. When the incident angle of light to the filler is θ1 (°), the exit angle of the light incident on the filler is θ2 (°), the refractive index of the filler is n, the length along a direction perpendicular to the height direction from one end of the upper surface of the filler in a cross section along the height direction of the filler to a portion on the upper surface of the base corresponding to the other end of the lower surface of the filler is L (mm), and the height of the filler in the cross section is H (mm), The irradiation means is configured to irradiate the filler such that the relationship sinθ2 = (sinθ1) / n and L / H < tanθ2 is satisfied, in the LED inspection apparatus according to means 1.

[0018] According to the above means 3, it becomes more certain that the light irradiated from the irradiation means does not directly irradiate the upper surface of the base. Therefore, the effect of improving the inspection accuracy can be obtained more certainly.

[0019] Means 4. The irradiation means is configured to irradiate the filler with light having the same wavelength as the wavelength of the light emitted by the LED chip, in the LED inspection apparatus according to means 1.

[0020] Note that the phrase "the same wavelength" includes not only exactly the same wavelength but also generally the same wavelength (for example, wavelengths that differ by 10 nm or less).

[0021] According to the above means 4, the filler can be made to emit light in substantially the same manner as when the LED is in use (when the LED chip emits light). Therefore, an inspection assuming the use of the LED can be performed, and the inspection accuracy can be further improved.

[0022] Means 5. An LED manufacturing apparatus comprising the LED inspection apparatus according to means 1.

[0023] According to the above means 5, the same operational effects as those of the above means 1 are achieved.

[0024] Means 6. A filling means for filling the filler on the base, and a filling control means capable of feedback controlling the filling means based on the determination result by the determination means, in the LED manufacturing apparatus according to means 5.

[0025] According to the above-mentioned means 6, the filling means can be feedback-controlled based on the judgment result by the judging means. Therefore, the amount of filler to be filled can be appropriately adjusted, and the quality of the LED as a product can be improved. In addition, since the pass / fail judgment is performed at the stage when the multiple LEDs are connected, i.e., before the multiple LEDs are separated, and the feedback control is performed based on the judgment result, it is possible to more reliably prevent the production of a large number of defective LEDs (with inappropriate filler conditions) before the feedback control is performed. As a result, the productivity (yield) can be increased.

[0026] Means 7. A heating means is provided for heating and hardening the filler filled by the filling means, The LED manufacturing apparatus according to Means 6, wherein the LED inspection device is configured to inspect the filler before heating by the heating means.

[0027] According to the above-mentioned means 7, an inspection is performed before the filler is heated and cured, and the filling means is feedback-controlled based on the inspection result (the judgment result by the judgment means). Therefore, it is possible to shorten the time required from filling with the filler to performing feedback control based on the state of the filler. This makes it possible to reduce the number of defective LEDs (with inappropriate filler state) manufactured, and further increase productivity (yield).

[0028] Means 8. The filler is provided with an additional filling means capable of additionally filling the filler, the LED inspection device is configured to be able to acquire an amount of the filler to be additionally filled by the additional filling means based on the image acquired by the imaging means; The LED manufacturing apparatus described in Means 7, wherein the additional filling means is configured to be able to additionally fill the filler based on the amount of the filler obtained by the LED inspection device before heating by the heating means.

[0029] According to the above-mentioned means 8, before the filler is heated and cured by the heating means, the additional filling means can additionally fill the filler based on the amount of filler (shortage of filler) acquired by the LED inspection device. Therefore, it is possible to more reliably prevent the occurrence of defective products caused by a shortage of filler, and further increase productivity (yield).

[0030] Means 9. An LED inspection method for inspecting a filler in an LED, in a stage where a plurality of LEDs each having an LED chip arranged on the upper surface of a predetermined base and a filler that contains a fluorescent agent capable of being excited by light emitted by the LED chip to emit fluorescence and is arranged on the upper surface of the base to seal the LED chip, are connected by a conductive lead frame, the method comprising: an irradiation step of irradiating the filler with light capable of exciting the fluorescent agent contained in the filler from above the filler toward the filler; an imaging step of imaging light emitted by the LED by the light irradiated in the irradiation step; and a determination step of determining whether the filler is good or bad based on the image acquired by the imaging step. An LED inspection method characterized in that in the irradiation process, light is irradiated from the side of the LED toward the filler at an incident angle such that the light incident on the filler does not irradiate the top surface of the base of the LED.

[0031] According to the ninth aspect, the same effects as those of the first aspect can be achieved.

[0032] Means 10. When the incident angle of light to the filler is θ1 (°), the exit angle of the light incident on the filler is θ2 (°), the refractive index of the filler is n, the length along a direction perpendicular to the height direction from one end of the upper surface of the filler in a cross section along the height direction of the filler to a portion on the upper surface of the base corresponding to the other end of the lower surface of the filler is L (mm), and the height of the filler in the cross section is H (mm), In the irradiation step, the LED inspection method according to means 9 is characterized in that light is irradiated onto the filler so as to satisfy the relationships of sinθ2 = (sinθ1) / n and L / H < tanθ2.

[0033] According to the above means 10, the same operational effects as those of the above means 3 are achieved.

[0034] Means 11. An LED manufacturing method including the LED inspection method according to means 9.

[0035] According to the above means 11, the same operational effects as those of the above means 1 are achieved.

[0036] Means 12. A filling step of filling the filler onto the base, A filling control step of feedback controlling the filling of the filler in the filling step based on the determination result in the determination step, the LED manufacturing method according to means 11 being characterized by including the filling control step.

[0037] According to the above means 12, the same operational effects as those of the above means 6 are achieved.

[0038] Means 13. Including a heating step of heating and curing the filler filled in the filling step, In the determination step, the LED manufacturing method according to means 12 is characterized in that the quality of the filler before heating by the heating step is determined.

[0039] According to the above means 13, the same operational effects as those of the above means 7 are achieved.

[0040] Means 14. Including an additional filling step of additionally filling the filler, In the determination step, based on the image acquired by the imaging step, the amount of the filler to be additionally filled in the additional filling step can be acquired, In the additional filling step, before heating in the heating step, based on the amount of the filler acquired in the determination step, the LED manufacturing method according to means 13 is characterized in that the filler can be additionally filled.

[0041] According to the above-mentioned means 14, the same effects as those of the above-mentioned means 8 are achieved.

[0042] In addition, the technical matters related to each of the above means may be combined as appropriate. Therefore, for example, the technical matters related to the above means 2 or 3 may be combined with the technical matters related to the above means 4. [Brief description of the drawings]

[0043] [Figure 1] FIG. 2 is a schematic cross-sectional view of an LED. [Diagram 2] 1 is a schematic plan view showing a plurality of LEDs connected by a lead frame. [Diagram 3] FIG. 2 is a block diagram showing the configuration of an LED manufacturing apparatus. [Figure 4] FIG. 2 is a schematic plan view showing a connected package body; [Diagram 5] FIG. 2 is a partially enlarged schematic plan view showing a state in which an LED chip is mounted on a lead frame. [Figure 6] 2 is a partially enlarged schematic plan view showing a state in which bonding wires are joined to an LED chip and a lead frame. FIG. [Figure 7] FIG. 2 is a schematic diagram showing a filling device, an LED inspection device, and the like. [Figure 8] 1 is an explanatory diagram for explaining the incident angle θ1 of light with respect to a filler, the exit angle θ2 of the incident light, the length L, and the height H. FIG. [Figure 9] FIG. 2 is a block diagram showing a functional configuration of the LED inspection device. [Figure 10] FIG. 13 is a block diagram showing a configuration of an LED manufacturing apparatus according to another embodiment. [Figure 11] FIG. 11 is a schematic diagram showing an additional filling device and the like in another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] An embodiment will now be described with reference to the drawings. First, the LED 1 will be described.

[0045] As shown in FIG. 1, an LED 1 includes an LED chip 2, a package 3, a lead frame 4, a bonding wire 5, and a filler 6.

[0046] The LED chip 2 is a light-emitting element that emits light of a predetermined wavelength when energized. In this embodiment, a blue LED chip that emits blue light is used as the LED chip 2. The LED chip 2 is disposed at approximately the center of the upper surface of the base 7, which will be described later. For convenience of illustration, the LED chip 2 is shown to be relatively thick in the drawings, but the actual LED chip 2 is thin.

[0047] The package 3 constitutes a frame to be filled with the filler 6. The package 3 has a flat bottom 3a, a side wall 3b erected on the outer edge side of the bottom 3a, and a cavity 3c which is a recessed space formed by the bottom 3a and the side wall 3b. The inner surface of the side wall 3b forms an inclined surface which gradually moves away from the center of the cavity 3c toward the upper side. The cavity 3c also has an opening 3c1 which opens toward the upper side. In this embodiment, the package 3 has a rectangular shape when viewed from above, but the shape of the package 3 may be changed as appropriate.

[0048] The lead frame 4 has a role of receiving power from the outside and providing electrical conduction to the LED chip 2. Two lead frames 4 are exposed in the cavity 3c, and these two lead frames 4 are embedded in the package 3 with their upper surfaces flush with the upper surface of the bottom 3a of the package 3. The LED chip 2 is fixed (die bonded) to the upper surface of one lead frame 4 exposed in the cavity 3c. In this embodiment, the bottom 3a of the package 3 and the lead frames 4 form a flat base 7, and the LED chip 2 and filler 6 are arranged on the upper surface of the base 7.

[0049] The bonding wire 5 is a conductive part for electrically connecting the lead frame 4 on the side to which the LED chip 2 is not fixed, to the LED chip 2. The bonding wire 5 is bonded to the lead frame 4 and the LED chip 2 by using, for example, ultrasonic waves.

[0050] The filler 6 is disposed on the upper surface of the base 7 by filling the cavity 3c, and serves to fix and seal the LED chip 2. The filler 6 is a transparent resin that is sufficiently permeable to the light emitted from the LED chip 2, and a fluorescent agent (filler) that can be excited by the light emitted from the LED chip 2 is mixed in a dispersed state into the transparent resin. The fluorescent agent in this embodiment emits yellow light when it receives the blue light emitted from the LED chip 2. Therefore, the LED 1 emits white light by utilizing the blue light emitted from the LED chip 2 and the yellow light emitted by the filler 6 (fluorescent agent).

[0051] In the manufacturing process, the LEDs 1 are connected in parallel by the lead frame 4 (see FIG. 2). By cutting the lead frame 4, an LED package including one or more LEDs 1 can be obtained.

[0052] Next, a description will be given of an LED manufacturing apparatus 10 for manufacturing the LED 1. As shown in Fig. 3, the LED manufacturing apparatus 10 includes a chip mounting apparatus 11, a die bonding apparatus 12, a wire bonding apparatus 13, a filling apparatus 14, an LED inspection apparatus 15, a resin heating apparatus 16, and a final inspection apparatus 17. In this embodiment, the filling apparatus 14 constitutes the "filling means", and the resin heating apparatus 16 constitutes the "heating means".

[0053] The chip mounting device 11 mounts an LED chip at a predetermined position on the lead frame 4 (see FIG. 5). Incidentally, a package assembly 8 (see FIG. 4) in which the lead frame 4 and a plurality of packages 3 are integrated is supplied to each of the above-mentioned devices, including the chip mounting device 11. The chip mounting device 11 performs mounting processing of an LED chip 2 on the lead frame 4 at a predetermined position on the package assembly 8.

[0054] The die bonding device 12 is provided downstream of the chip mounting device 11 along the transport direction of the connected package body 8, and fixes the LED chip 2 to the lead frame 4 using a predetermined die bonding material.

[0055] The wire bonding apparatus 13 is provided downstream of the die bonding apparatus 12, and electrically connects the lead frame 4 and the LED chip 2 by joining the bonding wire 5 to the lead frame 4 and the LED chip 2 (see FIG. 6).

[0056] The filling device 14 is provided downstream of the wire bonding device 13, and fills the cavity 3c with the filler 6. The filling device 14 has a function of adjusting the amount and time of filling the cavity 3c with the filler 6. The filling device 14 is configured to be feedback controlled by a filling control unit 21 (see FIG. 7, etc.).

[0057] The filling control unit 21 performs feedback control of the filling device 14 based on the quality determination result of the filler 6 by the determination unit 336 described later and control information obtained by the control information acquisition unit 337 described later. When the determination unit 336 determines that the filler 6 is defective, the filling control unit 21 controls the filling device 14 to adjust the amount of filler 6 filled into the cavity 3c.

[0058] In this embodiment, the adjustment amount of the filler 6 when the determination unit 336 determines that the filler 6 is defective is set to a fluctuating amount based on the control information. Of course, the adjustment amount of the filler 6 may be set to a predetermined constant amount. In this embodiment, the filling control unit 21 constitutes a "filling control means." Furthermore, the process of filling the cavity 3c with the filler 6 by the filling device 14 corresponds to the "filling process," and the process of feedback-controlling the filling of the filler 6 by the filling control unit 21 corresponds to the "filling control process."

[0059] The LED inspection device 15 inspects the state of the filler 6 in each LED 1 at the stage where the LEDs 1 (packages 3, etc.) are connected by the lead frame 4. In this embodiment, the LED inspection device 15 inspects particularly the amount of filler 6, and is provided immediately downstream of the filling device 14. The LED inspection device 15 will be described in detail later.

[0060] The resin heating device 16 is provided downstream of the LED inspection device 15, and heats the filler 6 in a softened state to harden the filler 6. In this embodiment, the process of heating and hardening the filler 6 by the resin heating device 16 corresponds to the "heating process".

[0061] The final inspection device 17 is provided downstream of the resin heating device 16, and performs final inspection of the LEDs 1. For example, the final inspection device 17 causes the LEDs 1 to emit light by applying current, and measures the wavelength, brightness, color, etc. of the light emitted from the LEDs 1, and performs inspection of the LEDs 1 based on the measurement results. Note that the inspection by the final inspection device 17 is performed after the lead frame 4 is cut to obtain an LED package including one or multiple LEDs 1.

[0062] Although not shown, the LED manufacturing equipment 10 is provided with a conveyor or the like for transporting the assembled package 8 between the above-mentioned devices, such as between the chip mounting device 11 and the die bonding device 12. In addition, between the LED inspection device 15 and the resin heating device 16 and downstream of the final inspection device 17, branching devices (not shown) are provided for discharging the LEDs 1 determined to be defective by the inspection devices 15, 17 out of the system.

[0063] Next, the configuration of the LED inspection device 15 will be described. The LED inspection device 15 inspects the filler 6 in the LED 1 after the cavity 3c is filled with the filler 6 and before the filler 6 is heated by the resin heating device 16. As shown in Fig. 7, the LED inspection device 15 includes a lighting device 31, a camera 32, and an image processing device 33. Note that in Fig. 7 and other figures, hatching of the filler 6 may be omitted for convenience of illustration. In this embodiment, the lighting device 31 constitutes the "illumination means" and the camera 32 constitutes the "imaging means".

[0064] The lighting device 31 irradiates the filler 6 from above with light capable of exciting the fluorescent agent contained in the filler 6. In this embodiment, the light irradiated from the lighting device 31 is blue light, and has the same wavelength as the light emitted by the LED chip 2. Note that the term "same wavelength" does not only mean the strictly same wavelength, but also includes wavelengths that are roughly the same (for example, wavelengths that differ by 10 nm or less). In this embodiment, the process of irradiating the filler 6 with light from the lighting device 31 corresponds to the "irradiation process".

[0065] The illumination device 31 is configured with a ring illumination having a circular shape in a plan view, and is disposed at a position surrounding the filler 6. The illumination device 31 irradiates light from the side of the LED 1 toward the filler 6 so that the light incident on the filler 6 is at an incident angle such that the light does not irradiate the upper surface of the base 7 (part of the base 7 that overlaps with the filler 6 when viewed in a plan view). As a result, the light that has entered the filler 6 and has not yet been reflected by the components of the LED 1 (parts other than the filler 6, such as the package 3) is not irradiated onto the upper surface of the base 7. In this embodiment, the light that has entered the filler 6 travels toward the inner surface of the side wall 3c, but when reflected by the inner surface of the side wall 3b, after reflection, it travels toward the opening 3c1 located on the opposite side to the upper surface of the base 7. Therefore, the light that has entered the filler 6 and has reflected by the components of the LED 1 is also not irradiated onto the upper surface of the base 7.

[0066] In the present embodiment, as shown in FIG. 8, in order to prevent light from irradiating the upper surface of the base 7, the illumination device 31 is set to irradiate the filler 6 so as to satisfy the relationships of sinθ2 = (sinθ1) / n and L / H < tanθ2. Here, θ1 (°) is the incident angle of light from the illumination device 31 to the filler 6, θ2 (°) is the exit angle of the light incident on the filler 6, and n is the refractive index of the filler 6. Also, L (mm) is the length along the direction orthogonal to the height direction in the cross section along the height direction of the filler 6, from one end 6e of the upper surface of the filler 6 to the portion 7e corresponding to the other end of the lower surface of the filler 6 on the upper surface of the base 7. Further, H (mm) is the height of the filler 6 in the cross section.

[0067] The camera 32 is disposed directly above the LED 1 and is constituted by a camera (for example, a CCD camera or a CMOS camera, etc.) that is sensitive to the light emitted by the LED 1 at least by the light irradiated from the illumination device 31. The relative position of the camera 32 with respect to the LED 1 is set such that its optical axis O is orthogonal to the upper surface of the base 7 and overlaps with the axis CL passing through the plane center of the LED 1.

[0068] Also, the camera 32 has an image pickup element (not shown) constituted by, for example, a CCD area sensor or a CMOS sensor, etc., and the image pickup element picks up the light emitted by the LED 1 by the light irradiated from the illumination device 31. The image (image data) acquired by the camera 32 (image pickup element) is a luminance image (luminance image data) having information related to luminance (information about the luminance of each pixel), and is sent to the image processing device 33. In the present embodiment, the step of picking up the light emitted by the LED 1 by the light irradiated from the illumination device 31 corresponds to the "image pickup step".

[0069] In addition, when there is no problem with the state (quantity) of the filler 6, an image in which the entire area of the filler 6 has high luminance is acquired. On the other hand, when there is a problem with the state (quantity) of the filler 6 (when the quantity of the filler 6 is insufficient), an image in which a part or the entire area of the filler 6 has low luminance is acquired.

[0070] The image processing device 33 comprises a computer including a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores various programs and fixed value data, a RAM (Random Access Memory) that temporarily stores various data when executing various arithmetic processing, and peripheral circuits for these.

[0071] 9, the image processing device 33 functions as various functional units such as a main control unit 331, an illumination control unit 332, a camera control unit 333, a display control unit 334, an image acquisition unit 335, a determination unit 336, and a control information acquisition unit 337, which will be described later, by the CPU operating in accordance with various programs. In this embodiment, the determination unit 336 constitutes the "determination means."

[0072] However, the various functional units are realized through cooperation of various hardware such as the CPU, ROM, RAM, etc., and there is no need to clearly distinguish between functions realized by hardware and functions realized by software, and some or all of these functions may be realized by hardware circuits such as ICs.

[0073] Furthermore, the image processing device 33 is provided with an input unit 33a consisting of a keyboard, mouse, touch panel, etc., a display unit 33b consisting of an LCD display or the like and equipped with a display screen capable of displaying various types of information, a memory unit 33c capable of storing various types of data, programs, calculation results, inspection results, etc., and a communication unit 33d capable of transmitting and receiving various types of data to and from the outside.

[0074] First, prior to describing the above-mentioned functional units constituting the image processing device 33, the display unit 33b, the storage unit 33c, and the communication unit 33d will be described.

[0075] The display unit 33b is configured to be able to display various information stored in the storage unit 33c. Therefore, the display unit 33b can display an image obtained by the camera 32, a binarized image described below, thresholds used for pass / fail determination (for example, an area threshold and a binarization threshold described below), pass / fail determination results, control information described below, and the like.

[0076] The storage unit 33c is configured with a storage device such as a hard disk drive (HDD) or a solid state drive (SSD), and stores, for example, a luminance image (luminance image data) and a pass / fail judgment result. The storage unit 33c also stores an area threshold value, which is a threshold value used in the pass / fail judgment process, a binarization threshold value, which is a threshold value used in the binarization process, and the like.

[0077] The communication unit 33d is equipped with a wireless communication interface conforming to a communication standard such as a wired LAN (Local Area Network) or a wireless LAN, and is configured to be able to transmit and receive various data to and from the outside. The pass / fail judgment result performed by the judgment unit 336 is output to the branching device via the communication unit 33d, and the LEDs 1 judged as defective are discharged outside the system. In addition, the pass / fail judgment result by the judgment unit 336 and the control information obtained by the control information acquisition unit 337 are output to the filling control unit 21 via the communication unit 33d, and the filling control unit 21 performs feedback control of the filling device 14 based on the judgment result and the control information.

[0078] Next, the above-mentioned various functional units constituting the image processing device 33 will be described in more detail.

[0079] The main control unit 331 is a functional unit that is responsible for controlling the entire LED inspection device 15, and is configured to be able to transmit and receive various signals to and from other functional units such as a lighting control unit 332 and a camera control unit 333.

[0080] The lighting control unit 332 is a functional unit that controls the lighting device 31 based on a command signal from the main control unit 331.

[0081] The camera control unit 333 is a functional unit that controls the camera 32, and controls the image capturing timing, camera gain, shutter speed, and the like by the camera 32 based on a command signal from the main control unit 331.

[0082] The display control unit 334 controls the display contents on the display unit 33b based on the information stored in the storage unit 33c.

[0083] The image acquisition unit 335 is a functional unit for acquiring a luminance image (luminance image data) captured and acquired by the camera 32. The acquired luminance image (luminance image data) is stored in the storage unit 33c.

[0084] The judgment unit 336 is a functional unit that judges the quality of the filler 6 based on the image (luminance image data) acquired by the camera 32. As described above, the camera 32 acquires an image of the filler 6 before it is heated by the resin heating device 16, and therefore the judgment unit 336 in this embodiment judges the quality of the filler 6 before it is heated. In judging the quality, the judgment unit 336 first acquires a binary image (binary image data) by performing a binarization process on the luminance image (luminance image data) acquired by the camera 32 using a binarization threshold stored in the storage unit 33c. In the binary image, pixels whose luminance is equal to or greater than the binarization threshold are designated as "1 (bright area)" and pixels whose luminance is less than the binarization threshold are designated as "0 (dark area)."

[0085] Then, the determination unit 336 calculates the area (number of pixels) of the connected components of the bright parts in the binarized image, and determines the filler 6 to be a "good product" if the calculated area is equal to or greater than the area threshold. On the other hand, the determination unit 336 determines the filler 6 to be a "defective product" if the calculated area is less than the area threshold. The result of the quality determination is stored in the memory unit 33c. In this embodiment, the process of determining the quality of the filler 6 based on the image acquired by the camera 32 corresponds to the "determination process".

[0086] The determination unit 336 may determine the quality of the filler 6 based on whether the connected components of the bright parts have a predetermined shape. Therefore, the determination unit 336 may determine the quality of the filler 6 by, for example, acquiring one or more predetermined shape features (e.g., center of gravity position, Feret diameter, circumference, equivalent circle diameter, absolute maximum length, etc.) from the connected components of the bright parts and comparing the acquired shape feature with a judgment reference amount stored in advance in the storage unit 33c.

[0087] The control information acquisition unit 337 acquires control information (adjustment amount of filler 6) used for feedback control of the filling device 14 based on the image acquired by the camera 32. The control information acquisition unit 337 calculates the amount of filler 6 to be filled from the filling device 14 into the cavity 3c based on information related to the luminance of the filler 6 (for example, maximum luminance or average luminance) in the luminance image (luminance image data) acquired by the camera 32. Then, the control information acquisition unit 337 acquires the difference between the calculated filling amount and the current filling amount as control information (adjustment amount). The acquired control information is output to the filling control unit 21 via the communication unit 33d.

[0088] As described above in detail, according to this embodiment, the lighting device 31 irradiates light from the side of the LED 1 toward the filler 6 at an incident angle such that the light incident on the filler 6 does not irradiate the upper surface of the base 7. This makes it possible to more reliably prevent the influence of reflected light from the upper surface of the base 7, and thus makes it possible to obtain an image that more clearly shows the state of the filler 6. This makes it possible to inspect the state of the filler 6 with high precision.

[0089] In addition, during the inspection, the LEDs 1 are not illuminated by the light emitted from the LED chip 2, but are illuminated by the light irradiated from the lighting device 31. Therefore, even at the stage where a plurality of LEDs 1 are connected, the state of the filler 6 in each LED 1 can be inspected with high accuracy.

[0090] Further, the determination unit 336 obtains a binarized image by performing binarization processing on the luminance image, and determines the filler 6 as "good product" when the area of the connected component of the bright part in the binarized image is equal to or greater than a predetermined area threshold, or when the connected component has a predetermined shape. Therefore, the inspection of the filler 6 can be accurately performed without excessively increasing the processing burden.

[0091] Furthermore, the lighting device 31 irradiates the filler 6 with light so as to satisfy the relationships of sinθ2 = (sinθ1) / n and L / H < tanθ2. Therefore, it is more reliably possible to prevent the light irradiated from the lighting device 31 from irradiating the upper surface of the base 7. Accordingly, the effect of improving the inspection accuracy can be more reliably obtained.

[0092] In addition, the lighting device 31 irradiates the filler 6 with light having the same wavelength as the light emitted by the LED chip 2. Therefore, the filler 6 can be made to emit light in substantially the same manner as when the LED 1 is used (when the LED chip 2 emits light). Accordingly, an inspection assuming the use of the LED 1 can be performed, and the inspection accuracy can be further improved.

[0093] In addition, since the filling device 14 is feedback-controlled based on the determination result by the determination unit 336 and the like, the filling amount of the filler 6 can be appropriately adjusted, and the quality of the LED 1 as a product can be improved. Also, since the pass / fail determination is performed at the stage where a plurality of LED 1s are connected, that is, at the stage before separating the plurality of LED 1s, and feedback control is performed based on the determination result, it is more reliably possible to prevent a large number of defective products (LED 1s with inappropriate filling amounts of the filler 6) from being manufactured before the feedback control is performed. As a result, productivity (yield) can be increased.

[0094] Furthermore, particularly in this embodiment, an inspection is performed before the filler 6 is heated and hardened, and the filling device 14 is feedback-controlled based on the inspection result (the judgment result by the judgment unit 336). Therefore, it is possible to shorten the time required from when the filler 6 is filled until feedback control based on the state of the filler 6 is performed. This makes it possible to reduce the number of defective LEDs 1 (with an inappropriate amount of filler 6) manufactured, and further increase productivity (yield).

[0095] The present invention is not limited to the above-described embodiment, and may be implemented as follows: Of course, other applications and modifications not exemplified below are also possible.

[0096] (a) In the above embodiment, the LED chip 2 emits blue light, but the LED chip 2 may emit ultraviolet light. When using an LED chip 2 that emits ultraviolet light, the LED 1 emits white light by using fluorescent agents (red fluorescent agent, blue fluorescent agent, and green fluorescent agent) that emit red, blue, and green light in response to ultraviolet light as the fluorescent agents of the filler 6.

[0097] Also, the LED 1 may be configured to emit white light by using an LED chip 2 that emits blue light and blue and green phosphors. Furthermore, the LED 1 may be configured to emit white light by using an LED chip that emits purple light and a Krums phosphor and a blue phosphor.

[0098] In addition, the LED 1 may emit a color other than white. For example, the LED 1 may be configured to emit light of a color such as green, yellow, orange, or red by receiving blue light emitted from the LED chip 2 with a fluorescent agent.

[0099] (b) In the above embodiment, the inspection of the filler 6 by the LED inspection device 15 is performed before heating by the resin heating device 16, but it may be performed after heating by the resin heating device 16. In this case, the filler 6 after hardening, that is, the filler 6 in its final state, can be inspected, so that the inspection accuracy of the filler 6 can be further improved.

[0100] (c) In the above embodiment, the judgment unit 336 judges the quality of the filler 6 using the area and shape of the connected components of the bright parts in the binarized image, but other elements may be used. Therefore, the judgment unit 336 may judge the quality of the filler 6 using, for example, the dark parts in the binarized image.

[0101] Furthermore, the determination unit 336 may not perform binarization processing on the image acquired by the camera 32. In this case, the determination unit 336 may, for example, extract a portion corresponding to the filler 6 from the image acquired by the camera 32, and perform pass / fail determination using the brightness of each pixel constituting the extracted portion (for example, the brightness difference between pixels, etc.).

[0102] (d) In the above embodiment, the LED inspection device 15 particularly inspects the amount of filler 6, but may inspect items other than the amount of filler 6. Therefore, for example, inspection may be performed on items such as the viscosity of the filler 6, the dispersion state, amount, and concentration of the fluorescent agent contained in the filler 6. Inspection of these items may be performed by using, for example, the luminance of a portion of the luminance image corresponding to the filler 6, the change in luminance at that portion, the maximum and minimum luminance values ​​at that portion, etc.

[0103] (e) In the above embodiment, the package 3 has the side wall 3b, but the package 3 does not have to have the side wall 3b. Therefore, the LED 1 may have the filler 6 with the side surface exposed.

[0104] (f) In the above embodiment, the LED 1 has one LED chip 2 , but it may have a plurality of LED chips 2 .

[0105] (g) As shown in Figures 10 and 11, the LED manufacturing apparatus 10 may include an additional filling device 22 capable of additionally filling the filler 6 into the cavities 3c, downstream of the LED inspection device 15 and upstream of the resin heating device 16 in the transport direction of the connected package body 8. The LED manufacturing apparatus 10 may also include an additional filling control unit 23 that controls the additional filling device 22. The additional filling device 22 constitutes an "additional filling means."

[0106] If the amount of the filler 6 filled by the filling device 14 is insufficient, the additional filling device 22 may be configured to additionally fill the cavity 3c with the filler 6 before the resin heating device 16 heats the filler 6, under the control of the additional filling control unit 23. Whether or not the amount of the filler 6 filled is insufficient (i.e., whether the amount of the filler 6 is good or bad) can be determined by the determination unit 336 of the LED inspection device 15, and the additional filling control unit 23 uses this determination result to control the additional filling by the additional filling device 22. The amount of the filler 6 to be additionally filled by the additional filling device 22 (in other words, the amount of the filler 6 that is insufficient) can be acquired by the determination unit 336 of the LED inspection device 15 based on an image acquired by the camera 32, and the additional filling control unit 23 uses the acquired amount to control the amount of the filler 6 to be filled by the additional filling device 22 and the filling time. The determination unit 336 can acquire the amount of the filler 6 to be additionally filled based on, for example, the brightness of a portion corresponding to the filler 6 in the brightness image. The process of additionally filling the filler 6 by the additional filling device 22 corresponds to the "additional filling process".

[0107] By configuring the filler 6 to be refillable as described above, it is possible to more reliably prevent the occurrence of defective products caused by a shortage of the filler 6. This makes it possible to further increase productivity (yield). [Explanation of symbols]

[0108] 1...LED, 2...LED chip, 4...lead frame, 6...filler, 7...base, 10...LED manufacturing apparatus, 14...filling apparatus (filling means), 15...LED inspection apparatus, 16...resin heating apparatus (heating means), 21...filling control section (filling control means), 22...additional filling apparatus (additional filling means), 31...illumination device (irradiation means), 32...camera (imaging means), 336...judgment section (judgment means).

Claims

1. 1. An LED inspection device for inspecting a filler in an LED, the filler including an LED chip disposed on an upper surface of a predetermined base and a fluorescent agent capable of emitting fluorescence upon excitation by light emitted by the LED chip, the filler being disposed on the upper surface of the base and sealing the LED chip, the LED inspection device being connected to the LED chip by a conductive lead frame, the LED inspection device comprising: an irradiation means for irradiating the filler with light capable of exciting the fluorescent agent contained in the filler from above the filler toward the filler; an imaging means for imaging light emitted by the LED in response to light irradiated from the irradiating means; a determination means for determining whether the filler is good or bad based on the image acquired by the imaging means, The LED inspection device is characterized in that the irradiation means is configured to irradiate light from the side of the LED toward the filler so that the light incident on the filler is at an incident angle such that the light does not irradiate the top surface of the base of the LED.

2. The imaging means acquires, as the image, a luminance image having information related to luminance, 2. The LED inspection device according to claim 1, wherein the determination means is configured to obtain a binary image by performing a binarization process on the luminance image using a predetermined binarization threshold, and to determine that the filler is a non-defective product when an area of ​​a connected component of a bright part in the binary image is equal to or larger than a predetermined area threshold, or when the connected component has a predetermined shape.

3. Let the incident angle of light with respect to the filler be θ1 (°), the exit angle of light incident on the filler be θ2 (°), the refractive index of the filler be n, the length along a direction perpendicular to the height direction from one end of the upper surface of the filler in a cross section along the height direction of the filler to a portion on the upper surface of the base corresponding to the other end of the lower surface of the filler be L (mm), and the height of the filler in the cross section be H (mm), 2. The LED inspection device according to claim 1, wherein the irradiation means is configured to irradiate the filler with light so as to satisfy the relationships sin θ2 = (sin θ1) / n and L / H < tan θ2.

4. 2. The LED inspection device according to claim 1, wherein the irradiating means is configured to irradiate the filler with light having the same wavelength as that of the light emitted by the LED chip.

5. An LED manufacturing apparatus comprising the LED inspection apparatus according to claim 1.

6. A filling means for filling the filler onto the base; 6. The LED manufacturing apparatus according to claim 5, further comprising a filling control means capable of feedback-controlling the filling means based on a result of the determination by the determination means.

7. a heating means for heating and hardening the filler filled by the filling means, 7. The LED manufacturing apparatus according to claim 6, wherein the LED inspection device is configured to inspect the filler before heating by the heating means.

8. The filler is additionally filled by additional filling means, the LED inspection device is configured to be able to acquire an amount of the filler to be additionally filled by the additional filling means based on the image acquired by the imaging means, 8. The LED manufacturing apparatus according to claim 7, wherein the additional filling means is configured to be able to additionally fill the filler based on the amount of the filler obtained by the LED inspection device before heating by the heating means.

9. 1. An LED inspection method for inspecting a filler in a plurality of LEDs, the LEDs each having an LED chip disposed on an upper surface of a predetermined base and a filler that contains a fluorescent agent capable of emitting fluorescence upon being excited by light emitted by the LED chip and is provided on the upper surface of the base to seal the LED chip, the LED being connected to the LED chip by a conductive lead frame, the method comprising the steps of: an irradiation step of irradiating the filler with light capable of exciting the fluorescent agent contained in the filler from above the filler toward the filler; an imaging step of imaging light emitted by the LED by the light irradiated in the irradiation step; and a determination step of determining whether the filler is good or bad based on the image acquired by the imaging step. The LED inspection method is characterized in that in the irradiation process, light is irradiated from the side of the LED toward the filler at an incident angle such that the light incident on the filler does not irradiate the top surface of the base of the LED.

10. Let the incident angle of light with respect to the filler be θ1 (°), the exit angle of light incident on the filler be θ2 (°), the refractive index of the filler be n, the length along a direction perpendicular to the height direction from one end of the upper surface of the filler in a cross section along the height direction of the filler to a portion on the upper surface of the base corresponding to the other end of the lower surface of the filler be L (mm), and the height of the filler in the cross section be H (mm), 10. The LED inspection method according to claim 9, wherein in the irradiation step, the filler is irradiated with light so as to satisfy relationships of sin θ2=(sin θ1) / n and L / H<tan θ2.

11. An LED manufacturing method comprising the LED inspection method according to claim 9.

12. a filling step of filling the filler onto the base; 12. The LED manufacturing method according to claim 11, further comprising: a filling control step of feedback-controlling the filling of the filler in the filling step based on a result of the determination in the determination step.

13. A heating step of heating and curing the filler filled in the filling step, The LED manufacturing method according to claim 12 , wherein the determining step determines whether the filler is good or bad before being heated in the heating step.

14. The additional filling step includes additionally filling the filler, In the determination step, an amount of the filler to be additionally filled in the additional filling step can be acquired based on the image acquired in the imaging step, 14. The LED manufacturing method according to claim 13, wherein in the additional filling step, the filler can be additionally filled based on the amount of the filler acquired in the determination step before heating in the heating step.

Images