JP5931330B2 - Bare chip mounting surface light emitter manufacturing method and bare chip mounting surface light emitter - Google Patents

Description

  The present invention relates to a method of manufacturing a surface light emitting device in which a bare chip of a light emitting diode is directly mounted on a substrate, and in particular, manufacturing a surface light emitting device that can be manufactured by smoothing the surface when resin sealing is performed to protect the bare chip or the like. The present invention relates to a method and a surface light emitter thereof.

In various guide display boards using light-emitting diodes as light sources, a plurality of mounting-type LED units in which bare chips are sealed for each resin base or a plurality of bullet-type LED units sealed in a bullet-shaped resin cover for each bare chip (Hereinafter, these are collectively referred to as a bullet-type LED unit in this application) is attached to a base member, a diffusion plate is fixed to the base member, and characters, designs, etc. are printed on the diffusion plate.
As such a guidance display board, the "indicator lamp" of patent document 1 and the "light-emitting display board" of patent document 2 can be mentioned.

However, in these configurations of Patent Document 1 and Patent Document 2, by the time the guide display plate is completed, the manufacture of the bullet-type LED units, their mounting on the base member, printing on the diffusion plate, etc. And the process of attachment was required, and each process lacked continuity.
Further, the presence of the diffusion plate has led to an increase in the size (weight, thickness, etc.) of the guide display plate, and the manufacturing has been expensive.

JP 2001-42798 A JP 2003-15558 A

  Therefore, the present invention is not a method of manufacturing bullet-type LED units, mounting them on a substrate, printing on a diffusion plate, and mounting, but a series of steps from mounting a bare chip on a substrate to printing on a surface light emitter. It is an object of the present invention to provide a method for manufacturing a surface light emitter that can be converted into a surface light emitter and the surface light emitter.

In order to solve the above problems, a step of attaching a metal foil having a plurality of protrusions on the resin substrate by biting the protrusions into the resin substrate, a step of etching the metal foil into a predetermined wiring pattern, The step of bonding a bare chip of a light emitting diode on the wiring pattern and bonding the plating layer of the electrode of the bare chip, and heating the coating material dripped onto the resin substrate manufactured by the above steps, increase the viscosity. And the step of heating the resin substrate itself so that the heating is not affected by the resin substrate, and the heated coating material is branched into several strips corresponding to the width of the resin substrate. by dropping to the surface, a step to improve the accuracy of the smoothing of the surface, after curing the coating material, letters and patterns on the surface of the coating layer formed And as the manufacturing method of the bare chip mounting surface light emitter, characterized in that by adding the step of printing (claim 1).

The method of manufacturing a bare chip mounting surface light emitter according to claim 1, wherein the coating material is of a rapid curing type (the invention according to claim 2 ).

The method for manufacturing a bare chip mounting surface light emitter includes a step of arranging a bare chip of a light emitting diode corresponding to a printed layer formed by the printing step on the wiring pattern (claim 3 ). invention).

Affixed on the resin substrate and pressed to form an anchor portion on the substrate, and a metal foil that is etched into a predetermined wiring pattern and applied to the wiring pattern A bare chip of a light emitting diode to which an electrode is connected via a plating layer, a printed layer formed at least excluding a region where the bare chip is arranged and a region to be punched or cut, and a coating material dropped onto the resin substrate A bare chip mounting surface light emitting device comprising a smooth coating layer formed by the above and a printed layer of characters and designs directly printed thereon .

Factors related to the smoothing of the liquid coating material include the viscosity and surface tension of the coating material, the thickness of the coating film, and the undulation (wavelength) of the peaks and valleys formed by the dropped coating material. And smoothing is accelerated | stimulated, so that a viscosity is low, surface tension is high, the thickness of a coating film is thick, and the wavelength of a wave | undulation is small.
  Further, since the viscosity of the coating material increases with time, it is desirable to reduce the dripping time of the coating material with respect to the coating material application area in order to increase the smoothing accuracy.
  Therefore, in the present invention, focusing on the viscosity of the coating material and the waviness of the coating material among these elements, the coating process is improved and the smoothing accuracy can be increased.

That is , the coating material itself is heated to reduce the viscosity, and the resin substrate itself is also heated so that the heating is not affected by the resin substrate.
Further, in order to reduce the wave length of the undulation of the coating material, the coating material was dropped in several branches corresponding to the width of the resin substrate.
This also means reducing the drip time.
Therefore, the smoothing of the coating material is enhanced, and printing can be performed directly on the surface after curing.

Process explanatory diagram of bare chip mounting surface light emitter, Same schematic cross-sectional view, (A) and (b) Detailed cross-sectional view of the same, A perspective view of a bare chip mounting surface light emitter, Plan view of bare chip mounting surface light emitter, An enlarged plan view of a convex coating layer constituting the light emitter, Same schematic cross-sectional view, Same schematic cross-sectional view, Vertical cross-sectional view of bare chip mounting surface light emitter, Vertical cross-sectional view of bare chip mounting surface light emitter, Process explanatory diagram of bare chip mounting surface light emitter, Plan view of bare chip mounting surface light emitter, Front view of bare chip mounting surface light emitter, An enlarged plan view of a convex coating layer constituting the light emitter, Same schematic cross-sectional view, FIG. 14 is a cross-sectional view of the main part taken along line AA in FIG. 14; It is process explanatory drawing of a bare chip mounting surface light-emitting body.

A method for manufacturing the surface light emitter L according to the present invention will be described with reference to FIGS.
In this embodiment, a blue light emitting diode bare chip 3B (hereinafter referred to as blue bare chip 3B) is connected to the wiring pattern 20 of the resin substrate (printed board) 1, and the bare chip 3B is placed on the bare chip 3B. However, the present invention is not limited to this. However, the present invention is not limited to this.

(A) A metal foil 2 having a large number of protrusions 21 is pasted on the resin substrate 1 by biting the protrusions 21 into the resin substrate 1 (FIG. 1A).
For example, an adhesive is applied in advance to the attachment surface of the metal foil 2, and pressure bonding is performed so that the protrusions 21 bite into the resin substrate 1.

(B) The metal foil 2 is formed on a predetermined wiring pattern 20 (FIG. 1B).
That is, the metal foil 2 is etched to form a predetermined wiring pattern 20.
The formation method of the wiring pattern 20 can be performed using a conventionally known technique such as an etched foil method. The pinhole 10 formed by the biting of the protrusion 21 remains on the surface of the resin substrate 1 from which the metal foil has been removed by this etching.
The wiring pattern 20 is formed in the horizontal direction or the vertical direction of the resin substrate (printed substrate) 1 so as to connect the blue bare chips 3B in series.

(C) An auxiliary plating 4 as a plating layer and an electroless gold plating 5 are formed on the predetermined wiring pattern 20 in an overlapping manner (FIG. 1C).
On the wiring pattern 20 adjacent to the wiring pattern 20 to which the blue bare chip 3B is fixed, the mounting density can be increased by electroless plating, and nickel having a strong film is plated. Next, a gold plating 5 is applied on the auxiliary plating 4 by electroless plating.

(D) A printing layer 7 is formed in a region excluding at least a region where the gold plating 5 and the blue bare chip 3B are disposed (FIG. 1D).
These printing layers 7 are formed by silk printing.
At this time, in the present invention, when the surface light emitter L is divided by secondary processing such as punching or cutting with respect to the surface light emitter L by adjusting the range of the printed layer 7, The printed layer 7 is not formed in the region to be formed.

(E) The blue bare chip 3B is bonded and fixed on the wiring pattern 20 and bonded to the gold plating 5 using the gold wire 6 (FIG. 1E).
That is, for example, one electrode (for example, the N-side electrode) 30 of the blue bare chip 3B is directly connected to the wiring pattern 20 via the plating layer P, and the other electrode (for example, the P-side electrode) 31 is connected to the gold wire 6 By this, the gold plating 5 on the adjacent wiring pattern 20 is connected. The electrodes and wiring of each blue bare chip 3B can be easily connected by wire bonding equipment. In this case, as described above, the auxiliary plating 4 is formed by heat welding and pressure by a welding machine applied to the bonding point. By welding, the resin substrate 1 is protected from deformation and bonding reliability is improved.

  Next, the resin substrate 1 that has undergone the above steps is heated using a heating means H composed of a heater or the like, and the coating material 8 that has been heated and mixed with the phosphor 9 is injected. Using means PO, it is dropped into several strips corresponding to the width of the resin substrate 1 and dropped (FIG. 1 (F)). The temperature at the time of heating is preferably about 50 ° C to 70 ° C. At that time, a fence means may be provided on the outer periphery of the resin substrate 1 in order to prevent “sag” of the coating material 8.

  Then, after confirming hardening of the coating layer 80, the printing layer 81 is formed in the surface (FIG. 1 (G)).

  As the resin substrate 1, it is desirable to use a heat-resistant organic resin substrate having excellent heat dissipation performance, and specifically, a phenol resin-based substrate containing a thermally conductive filler is used. An epoxy resin substrate, a glass woven epoxy resin substrate, a glass nonwoven fabric epoxy resin substrate, or the like may be used.

  The metal foil 2 forms the wiring pattern 20. For example, a material having excellent conductivity such as copper, silver, gold, or platinum is used, and an inexpensive copper foil is preferably used. A large number of protrusions 21 are formed in advance on the back surfaces of these metal foils.

  For the bare chip 3B of the blue light emitting diode, for example, an InGaN compound semiconductor having a peak wavelength of 465 nm is used.

  As the yellow phosphor 9, for example, a YAG (YTTRIUM ALUMINUM GARNET) phosphor material or a BOS (BARIUM ORTHO-SILICATE) phosphor material is used. The phosphor is not particularly limited as long as it receives the excitation light of the bare chip 3B of the blue light emitting diode and emits white light. For example, a phosphor in which red and green are mixed (RG phosphor) may be used.

These phosphors are mixed with the coating material 8 constituting the coating layer 80 after being agitated by vacuum degassing and defoamed.
This is because bubbles enter when the coating material with high viscosity is agitated, and these bubbles obstruct the path of light and cause irregular reflection, resulting in no clean light. It depends.

The auxiliary plating 4 is preferably nickel plating on which a hard film is formed. As shown in FIG. 1 and the like, the auxiliary plating 4 is formed on the wire bonding point pattern portion for the gold wire 6 to which the electrode 30 of each blue bare chip 3B and the electrode 31 are connected by electroless plating. Applied.
The plated layer P is constituted by the auxiliary plating 4 and / or the gold plating 5 in this embodiment, but is not limited to these materials.

  The gold plating 5 applied on the auxiliary plating 4 is formed by electroless plating and is suitable for high-density mounting.

  The gold wire 6 is required to have good ohmic properties, mechanical connectivity, electrical conductivity and thermal conductivity with the electrodes 30 and 31 of the blue bare chip 3B. Specifically, gold, copper, platinum, Examples thereof include conductive wires using metals such as aluminum and alloys thereof.

The printed layer 7 is for concealing the wiring pattern 20 and adjusting the reflectance of the light emitter, and forms a printed layer having a color suitable for white light.
The printing method of the printing layer 7 is not specifically limited, For example, printing methods, such as silk printing, gravure printing, and offset printing, can be used, Usually, silk printing is performed.

  For the coating material 8, for example, a rapidly curable epoxy acrylic is used. Other acrylic resins or epoxy resins may be used.

  The printing layer 81 can be formed by silk printing or the like, and any ink can be used as long as it can form a strong film on the coating layer 80.

  In the above process, the pinhole 10 of the anchor portion is formed by adhering the metal foil 2 on the resin substrate 1 and pressurizing it, but the anchor portion is previously formed on the substrate such as aluminum by sandblasting etc. A body may be formed, and a wiring pattern may be formed by plating or the like. Alternatively, an anchor may be mechanically formed after an insulator is formed on a substrate such as aluminum and a wiring pattern is formed by plating or the like.

  Through the above steps, the surface light emitter L is attached to the resin substrate 1 and the resin substrate 1 and is pressed to form the pinhole 10 as an anchor portion on the substrate 1, and a predetermined amount. The metal foil 2 etched into the wiring pattern 20, the blue bare chip 3 B to which the electrodes 30 and 31 are connected via the auxiliary plating 4 and the gold plating 5 as the plating layer P applied on the wiring pattern 20, The printing layer 7 is formed except at least the area where the bare chip 3B is arranged and the area to be punched or cut, the smooth coating layer 80, and the printing layer 81 formed directly printed thereon. .

The effects of the method for manufacturing the surface light emitter L as described above are as follows.
(1) The coating material 8 itself is heated to lower the viscosity, and the heating is the resin substrate 1
The resin substrate 1 itself is also heated so as not to be affected by this, and the coating material 8 is branched into several strips and dropped, so that the wave length of the swell of the coating material 8 can be reduced and the dropping time can be reduced. The smoothness of the coating layer 80 can be increased.
(2) Since the smoothness of the coating layer 80 can be increased, it is possible to continuously serialize from mounting the bare chip to the substrate to printing on the surface light emitter.
(3) Since printing is performed directly on the coating layer 80, the printed layer 81 can be projected vividly by reaching the printing layer 81 without the light intensity of the blue bare chip 3B being attenuated.
(4) Since the light emitting surface is smoothed, the angle of view (viewing angle) of light emitted from the light emitting surface can be expanded.
(5) Since the coating layer 80 is in the pinhole 10 left on the resin substrate 1, the adhesiveness with the resin substrate 1 is extremely high. For this reason, by using the region where the coating layer 80 has penetrated into the pinhole 10 and performing secondary processing such as punching or cutting with a press, without causing the resin substrate 1 and the coating layer 80 to peel off, A surface light emitter L having a desired shape can be obtained.
(6) With the surface light emitter L, it is possible to provide a thin, light, excellent waterproof and inexpensive surface light emitter due to the fact that a diffusion plate is unnecessary and the following elements.
That is, the auxiliary plating 4 protects the resin substrate 1 from being deformed by heat welding and pressure welding by a welding machine applied to the bonding point, and improves bonding reliability. Therefore, the blue bare chip 3B can be mounted on a thin resin substrate (for example, 0.3 mm thick) by interposing the auxiliary plating 4 under the gold plating 5.
Further, by this action, the surface light emitter L having a thickness of 1.3 mm ± 0.1 including the coating layer 80 applied to the surface of the resin substrate 1 can be manufactured.
(7) Also, the anchor effect of the pinhole 10 formed on the substrate 1 enhances the adhesion and adhesion of the coating material 8 to the substrate 1, and is excellent in impact resistance, vibration resistance, and waterproof resistance. It is a surface light emitter that can be used as it is.

  In addition, an epoxy resin can be used as a coating material, and the curing agent used for this is not particularly limited as long as it exhibits a curing reaction with an epoxy resin, and a known curing agent is used. For example, a phenol resin Or an acid anhydride is preferable. In particular, when an acid anhydride curing agent is used, it is more preferable to use an acid anhydride because the optical properties of the cured product are remarkably improved.

  In addition, conventionally known additives such as antioxidants, colorants, coupling agents, modifiers, light (ultraviolet rays, visible rays, infrared rays) absorbers, fillers, and the like are added to the above resin compositions as necessary. Can be blended.

In the step of bonding the bare chip of the light emitting diode on the wiring pattern 20 of the present invention, the bare chip of the light emitting diode corresponding to the printed layer formed by the printing step may be arranged on the wiring pattern.
For example, as shown in FIG. 4, the bare chip 3R of the red light emitting diode may be arranged along the outline of the apple so as to correspond to the translucent printed layer 81 on which the apple is drawn.

Next, a configuration example of the bare chip mounting surface light emitter L1 (hereinafter, simply referred to as a surface light emitter L1) according to the present invention will be described with reference to FIGS. Detailed description of the same configuration as that of the surface light emitter L will be omitted.
The structure in which the surface light emitter L1 is different from the surface light emitter L is that a convex coating layer 8A in which a phosphor that converts the wavelength of light emitted from the bare chip 3B to white is mixed is uniformly formed on the bare chip 3B. Further, the coating layer 80 is formed thereon.

The convex coating layer 8A is dripped from above the blue bare chip 3B and cured, and is formed on a convex lens as shown in FIG.
Although the convex coating layer 8A is formed in a lens shape, it may be a curved surface having a curved surface or a curved surface partially having a flat surface.
Further, in this embodiment, the convex coating layer 8A is formed only on the blue bare chip 3B main body, but the convex coating layer 8A is formed so as to include the wiring pattern portion to which the gold wire 6 is connected as shown in FIG. You may make it form.

  Next, a method for manufacturing the surface light emitter L1 configured as described above will be described with reference to FIG.

In the process diagram of FIG. 11, steps common to the process diagram of FIG. 1 are indicated by the same diagram number, and the steps shown in FIGS. 11E and 11 F ′ are the same as those in FIGS. This is different from the step (F).
That is, as the step (E ′), the coating material 8 mixed with the phosphor 9 is dropped on the blue bare chip 3B and cured to form the convex coating layer 8A (FIG. 11E ′).
In the step (F ′), the coating material 8 excluding the phosphor 9 is used.

The surface light emitter L1 configured as described above exhibits the following operational effects in addition to the effects (1) to (7).
(8) Light rays emitted from the lens-like convex coating layer 8A are diffused and emitted in a wide range, and these light rays are emitted from the coating layer 80, so that a uniform surface light emitter can be obtained.
Other configurations and effects are the same as those of the above embodiment.

Next, a configuration example of the bare chip mounting surface light emitter L2 (hereinafter, simply referred to as a surface light emitter L2) according to the present invention will be described with reference to FIGS. The detailed description of the same configuration as that of the surface light emitters L and L1 is omitted.
The surface light emitter L2 is a full-color surface light emitter, and as shown in FIGS. 12 to 15, a red light emitting diode bare chip 3 </ b> R (hereinafter simply referred to as a bare chip 3 </ b> R), green, and so on A bare chip 3G of a light emitting diode (hereinafter simply referred to as bare chip 3G) and a bare chip 3B of a blue light emitting diode (hereinafter simply referred to as bare chip 3B) are connected. The coating layer 8A is formed uniformly and adjacently at equal intervals or substantially equal intervals, and the coating layer 80 is formed on the entire substrate from above.

For example, a GaP compound semiconductor having a peak wavelength of 700 nm is used for the bare chip 3R. The bare chip 3G uses, for example, an InGaN-based compound semiconductor having a peak wavelength of 520 nm. The bare chip 3B uses, for example, an InGaN compound semiconductor having a peak wavelength of 465 nm.
The bare chips 3R, 3G, and 3B are arranged at substantially equal intervals and at substantially equal distances with respect to the central axis 8c provided in the convex coating layer 8A.
In this embodiment, one set of bare chips 3R, 3G, and 3B is used as a set. However, a plurality of sets of bare chips 3R, 3G, and 3B may be set as a set in order to increase the light intensity.

The print layer 7 may be a color suitable for full color, for example, a black print layer, but is not particularly limited.
The silk dam 71 exhibits the following functions.
First, the shape of the convex coating layer 8A is formed so that the light beams of the bare chips 3R, 3G, and 3B can be mixed and emitted, and second, the shape of each convex coating layer 8A can be uniformly formed. Thirdly, the arrangement of the bare chips 3R, 3G, and 3B as a set with respect to the substrate is equally spaced as much as possible and the like.
That is, it does not prevent the fluid coating material forming the convex coating layer 8A from flowing out to an unintended region, as in a normal silk dam.
In this embodiment, the silk dam 71 has a diameter of about 5 mm, a width of about 0.3 mm, and a thickness of about 0.2 mm.
Instead of the silk dam 71, a ring-shaped pattern may be formed using a resist coated on the substrate surface, and this may be used as a bank portion.
Such a bank portion may be used for forming the convex coating layer 8A of the surface light emitter L2.

The configuration in which the convex coating layer 8A is different from the convex coating layer 8A of the surface light emitter L1 is that the convex coating layer 8A is formed in a convex shape by dripping and curing the coating material in the silk dam 71 described above.
The convex coating layer 8A is formed in a lens shape, but may be a curved surface having a curved surface or a flat surface in part.
Other configurations are the same as those of the surface light emitters L and L1.
The convex coating layer 8A of the surface light emitter L1 may be formed using the silk dam 71.

Next, a method for manufacturing the surface light emitter L2 configured as described above will be described with reference to FIG.
In the process diagram of FIG. 17, processes common to the process charts of FIGS. 1 and 11 are indicated by the same figure number, and the processes shown in FIGS. This is different from the first (D) and (E ′) steps.

(D ′) The silk dam 71 is formed in the circular area 70 where the gold plating 5 and the bare chips 3R, 3G, and 3B are disposed, and the printing layer 7 is formed in an area excluding this (FIG. 17D ′). ).
The printed layer 7 and the silk dam 71 are formed by silk printing.
At this time, in the present invention, when the surface light emitter L1 is divided by secondary processing such as punching or cutting with respect to the surface light emitter L1 by adjusting the range of the printing layer 7, The printed layer 7 is not formed in the region to be formed.

(E ′) The bare chips 3R, 3G, and 3B are bonded and fixed on the wiring pattern 20, and are bonded to the gold plating 5 by using the gold wire 6 (FIG. 17E ′).

The effects of the surface light emitter L2 having the above-described configuration are the same as the effects (1) to (8) of the surface light emitters L and L1, and further have the following effects.
(9) The conventional silk dam was intended to prevent the flowable coating material from flowing out to an unintended region. On the other hand, in the embodiment of the present invention, the shape of the first coating layer 8 is formed so that the light beams of the bare chips 3R, 3G, and 3B can be mixed and emitted, and the shape of each coating layer 8 can be uniformly formed. The purpose is to position each bare chip 3R, 3G, 3B on the substrate as equally spaced as possible and evenly. A surface light emitter can be provided.
(10) By connecting to the substrate for controlling the light emission of each bare chip 3R, 3G, 3B, a full-color surface light emitter can be obtained.

L L1 L2 Bare chip mounting surface light emitter 1 Resin substrate 10 Pinhole (anchor part)
2 Metal foil 20 Wiring pattern 21 Protrusion 3R 3B 3G Bare chip 30 31 Electrode P Plating layer 4 Auxiliary plating 5 Gold plating 6 Gold wire 7 Printing layer 70 Circular region 71 Silk dam (bank portion)
8 Coating material 8A Convex coating layer 80 Coating layer 81 Print layer

Claims (3)

A step of attaching a metal foil having a plurality of protrusions on the resin substrate by biting the protrusions into the resin substrate;
Etching the metal foil into a predetermined wiring pattern;
Bonding a bare chip of a light emitting diode on the wiring pattern and bonding a plating layer of an electrode of the bare chip;
Heating the coating material dripped onto the resin substrate manufactured by the above steps to lower the viscosity, and heating the resin substrate itself so that the heating is not affected by the resin substrate;
A step of branching the heated coating material into several strips corresponding to the width of the resin substrate and dropping it on the surface of the resin substrate to increase the smoothing accuracy of the surface;
A method for producing a bare chip mounting surface light emitter, comprising a step of printing characters and designs on the surface of a coating layer to be formed after curing the coating material.   The method of manufacturing a bare chip mounting surface light emitter according to claim 1, wherein the coating material is of a rapid curing type.   The method for manufacturing a bare chip mounting surface light emitter according to claim 1, further comprising a step of disposing a bare chip of a light emitting diode corresponding to a printed layer formed by the printing process on the wiring pattern.

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