JP5072405B2 - Light-emitting element mounting substrate and method for manufacturing the same - Google Patents

Description

  The present invention relates to a light emitting element mounting substrate in which light emitting elements such as LED chips are linearly arranged and mounted on a bowl-shaped wiring substrate, a light emitting element mounting substrate used therefor, and a method for manufacturing the same.

  2. Description of the Related Art In recent years, as a light source device that replaces a light source such as a light bulb, a light source diode array in which a plurality of light emitting diodes are arranged on a substrate is housed in a light source device body.

  For example, light source devices such as high-mount stop lamps and tail lamps for vehicles that use a light-emitting diode array as a light source have been put into practical use. Also known as backlights for liquid crystal display devices are light emitting diode (LED) chips arranged in a planar shape, and light emitting diode arrays (edge lights) in which LED chips are arranged linearly on the side of a light guide plate. Yes. Such a light emitting diode array and a light source device have advantages such as low power consumption, low heat generation, and long life compared to those using a light bulb or the like as a light source.

  In general, this type of light emitting diode array is configured by arranging a plurality of LED chips on a hard substrate such as a glass epoxy substrate. However, in the case of a hard substrate, for example, when the light emitting diode array is disposed in the light source device body whose inner shape is curved, each light emitting diode is efficiently disposed along the curved shape of the light source device body. It was difficult.

  Therefore, in Patent Document 1 below, for the purpose of solving the above problems, a flexible substrate in which at least a part of the conductive pattern is exposed on the surface side, and a surface disposed on the surface side of the flexible substrate, leads to the conductive pattern. There is disclosed a light-emitting diode array including a plurality of light-emitting diodes whose parts are surface-connected and whose bottom surfaces are close to the front surface side of the flexible substrate. Further, this Patent Document 1 describes that a plurality of light emitting diodes are arranged in a straight line and that the light emitting diode array is used in a curved state.

  However, the light emitting diode array disclosed in Patent Document 1 is simply a flexible surface mount type substrate, and the flexible substrate has little effect on increasing the reflection efficiency of the light emitting element. Further, since it is assumed that a light emitting diode having a lead portion is used instead of the LED chip, the flexible substrate does not have a function as a resin dam when potting a transparent resin or the like on the LED chip. Furthermore, in consideration of flexibility, heat radiation from the light emitting diode is performed using a silicon resin, but the resin has insufficient heat conductivity.

  On the other hand, in Patent Document 2 below, for the purpose of improving the heat dissipation from the LED chip, a metal substrate, a metal convex portion formed by etching at the mounting position of the light emitting element of the metal substrate, and the metal convex portion There is disclosed a light emitting element mounting substrate including an insulating layer formed around the electrode and an electrode portion formed in the vicinity of the metal protrusion.

  However, the technique described in Patent Document 2 also does not provide a function as a resin dam when increasing the reflection efficiency of the light emitting element or potting, as in the technique of Patent Document 1.

Japanese Patent Laid-Open No. 2002-232009 Japanese Patent Laying-Open No. 2005-167086

  Accordingly, an object of the present invention is to provide a light-emitting element mounting substrate that can increase the reflection efficiency of the light-emitting element, easily perform potting, and has excellent heat dissipation from the light-emitting element, and a method for manufacturing the same. is there.

The above object can be achieved by the present invention as described below.
The light-emitting element mounting substrate of the present invention is formed around a metal penetration part formed at a mounting position of the light-emitting element, a metal layer formed by etching the metal penetration part, and the metal penetration part on the metal layer. A light-emitting element mounting board comprising: a wiring board having a formed insulating layer; and an electrode part formed in the vicinity of the metal penetrating part; and a light-emitting element mounted on the wiring board. The flexible wiring board is curved in the shape of a bowl and curved toward the mounting side of the light emitting element, and a plurality of the metal through portions are linearly arranged at the bottom of the wiring board.

  According to the light emitting element mounting substrate of the present invention, since the wiring board is curved and formed in a bowl shape on the light emitting element mounting side, it is difficult for light to escape to the corners, and the reflection efficiency of the light emitting element can be improved. . Even when potting is performed, the wiring board is bowl-shaped so that potting can be easily performed. Furthermore, the heat dissipation from the light emitting element is improved by the metal penetrating portion formed at the mounting position of the light emitting element.

The wiring substrate is curved flexible wiring board der Ru case, by adjusting the degree of curvature becomes easy to change the way of reflection, also facilitates and fitting process by a curved, manufacturability (Assembly Performance) and freedom of incorporation.

Also, the wiring substrate, when having a metal layer connected to the metal penetrating portion on the back side of the light emitting element, by providing a metal layer such as this, heat dissipation from the light emitting element through the metal penetrating portion Can be further improved.

On the other hand, the substrate for mounting a light emitting element of the present invention includes a metal penetration part formed at a mounting position of the light emitting element, a metal layer formed by etching the metal penetration part, and the metal penetration part on the metal layer . A light emitting element mounting board comprising a wiring board having an insulating layer formed around and an electrode part formed in the vicinity of the metal penetration part, wherein the wiring board is curved toward the mounting side of the light emitting element. The flexible wiring board is formed in a bowl shape, and a plurality of the metal penetrating portions are linearly arranged at the bottom of the wiring board. The light-emitting element mounting substrate of the present invention is a substrate for mounting a light-emitting element. With such a substrate, the reflection efficiency of the light-emitting element can be increased, and even when potting is performed, it can be easily performed. The heat dissipation is excellent.

Another substrate for mounting a light-emitting element according to the present invention includes a metal penetrating portion formed at a mounting position of the light-emitting element, a metal layer formed by etching the metal penetrating portion, and the metal penetrating portion on the metal layer. A light-emitting element mounting substrate comprising a wiring board having an insulating layer formed around the part and an electrode part formed in the vicinity of the metal penetration part, the wiring board being curved toward the mounting side of the light-emitting element In addition, the flexible wiring board is formed in a bowl shape, and has a structure in which a plurality of bowl-like wiring boards are arranged side by side, and a plurality of the metal through portions are linearly arranged at the bottom of the wiring board. It is what. Such a light-emitting element mounting substrate can be used as a substrate for mounting the light-emitting element as it is or after being divided. When such a substrate is used to increase the reflection efficiency of the light-emitting element and perform potting. However, this can be easily performed and the heat dissipation from the light emitting element is excellent.

  On the other hand, the method for manufacturing a light emitting element mounting substrate of the present invention includes a step of dividing each light emitting element mounting substrate from a precursor in which a plurality of the light emitting element mounting substrates described above are arranged in parallel. It is a manufacturing method. For this reason, the light emitting element mounting substrate which improves the reflection efficiency of the light emitting element and can easily perform the potting and has excellent heat dissipation from the light emitting element by the above-described effects, while reducing productivity and low cost. Can be manufactured.

  In addition, a method for manufacturing a light-emitting element mounting substrate according to the present invention includes a step of mounting a light-emitting element on a plurality of the wiring substrates according to any one of the above-described arrangements, and a precursor obtained in the step. And a step of dividing the light emitting element mounting substrate.

  Thus, by dividing each light emitting element mounting substrate after mounting in the state of the wiring substrate, the light emitting element mounting substrate of the present invention can be manufactured at a lower cost while further improving the productivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a drawing showing an example of a light-emitting element mounting substrate according to the present invention, where (a) shows a cross-sectional view perpendicular to the longitudinal direction, and (b) shows a perspective view before division. 2A to 2G are process diagrams showing an example of a method for manufacturing a light emitting element mounting substrate of the present invention. In FIG. 1 (a), wire bonding and electrode portions arranged in the arrangement direction of a plurality of light emitting elements are schematically shown in a cross-sectional view perpendicular to the longitudinal direction so that the form of wire bonding can be easily understood. Show.

  As shown in FIG. 1A, the light-emitting element mounting substrate of the present invention includes a metal penetration part MB formed at the mounting position of the light-emitting element 15, and an insulating layer 40 formed around the metal penetration part MB. And a wiring board CB having an electrode portion 23a formed in the vicinity of the metal penetration part MB, and a light emitting element 15 mounted on the wiring board CB.

  In the present embodiment, the metal penetrating part MB is formed by etching, and has a mounting pad 23b formed on the upper surface thereof, and a power supply having an electrode part 23a formed at the same height in the vicinity of the mounting pad 23b. An example provided with a pattern for use is shown. Moreover, in this embodiment, the example in the case of having the metal layer 10 connected with the metal penetration part MB on the back surface side of the light emitting element 15 is shown. The metal layer 10 may be provided on substantially the entire surface of the wiring board CB, but may be partially formed as a pattern. The wiring substrate CB can supply power to the light emitting element 15.

  Examples of the light emitting element 15 include a light emitting diode chip (bare chip), a packaged surface mount type light emitting diode (chip LED), and a semiconductor laser chip. When a light emitting diode chip is used, there are two types of the back side, a cathode type and an anode type. In the present invention, the bare chip type light emitting element 15 is superior in terms of heat dissipation and mounting area.

  In the present embodiment, the light emitting element 15 is conductively connected to the electrode portions 23a on both sides. This conductive connection can be performed by connecting the upper electrode of the light emitting element 15 and each electrode portion 23 a by wire bonding or the like using the metal thin wire 17. As wire bonding, ultrasonic waves or a combination of this and heating can be used.

  In the light emitting element mounting substrate of the present invention, as shown in FIGS. 1A to 1B, the wiring board CB is curved and formed in a bowl shape on the mounting side of the light emitting element 15, and the metal penetrating part MB is also formed. A plurality are arranged linearly at the bottom of the wiring board CB. For this reason, even if a reflector is not separately provided, the reflection efficiency can be increased by the bowl-shaped wiring board CB curved toward the mounting side.

  In the present invention, “curved and formed into a bowl shape” refers to a cross-sectional shape that does not have a corner portion (a bent portion having an angle of 100 ° or less) through which light escapes, and preferably the cross section of the curved portion is a curved surface It is formed only by the flat part and curved surface of the bottom part. Specifically, cross-sectional shapes, such as circular arc shape, U shape, and a parabola shape, are mentioned.

  In the present invention, for example, when a bare chip is used as the light emitting element 15, it is preferable to cover the light emitting element 15 with a transparent resin or the like, and a convex transparent resin lens may be provided thereabove. Since the transparent resin lens has a convex surface, light may be efficiently emitted upward from the substrate. Examples of the lens having a convex surface include a columnar body having a convex lens section and extending in the longitudinal direction, and a circular or elliptical shape in plan view. The transparent resin and the transparent resin lens may be colored or contain a fluorescent material. In particular, when a yellow fluorescent material is included, white light can be generated using a blue light emitting diode.

  In this embodiment, the mounting pad 23b and the electrode part 23a on the upper surface of the metal penetration part MB can be formed at the same height, and both can form a substantially flat surface with respect to the light emitting element 15. The mounting method of the light emitting element 15 may be any bonding method such as conductive paste, double-sided tape, solder bonding, a heat radiating sheet (preferably a silicone heat radiating sheet), a method using a silicon or epoxy resin material. Metal bonding is preferable from the viewpoint of heat dissipation.

  The light emitting element mounting substrate of the present invention can be preferably manufactured by the following manufacturing method of the present invention. As shown in FIG.1 (b), the manufacturing method of the light emitting element mounting substrate of this invention is the process of dividing | segmenting each light emitting element mounting substrate from the precursor 1 in which the light emitting element mounting substrate of this invention was arranged in multiple numbers. Is included. The division into the light emitting element mounting substrate can be performed by, for example, a method of cutting along a cutting line 1a of the precursor 1 with a cutting device such as a dicer, a router, a line cutter, or a slitter.

  The method for manufacturing a light emitting element mounting substrate of the present invention includes a step of mounting the light emitting element 15 on a plurality of wiring substrates CB arranged side by side, and each light emitting element mounting substrate obtained from the precursor 1 obtained in the step. And a step of dividing. At that time, for example, a flat wiring board CB in which a plurality of wiring boards CB are arranged side by side can be bent as shown in FIG.

  As a manufacturing method of the wiring substrate CB constituting the precursor 1, a method of forming the metal through portion MB by etching is preferable. In particular, as shown in FIGS. 2A to 2C, a process of selectively etching the surface metal layer 22 laminated on the metal layer 10 to form the metal penetration MB at the mounting position of the light emitting element 15. It is preferable to include. In this embodiment, the surface metal layer 22 shows the example laminated | stacked on the metal layer 10 through another protective metal layer 21 which shows tolerance at the time of the etching.

  In this embodiment, first, as shown in FIG. 2A, a laminated plate in which a heat radiating metal layer 10, a protective metal layer 21, and a first metal layer 22 for forming a metal through portion MB are laminated. Prepare SP. The laminated plate SP may be manufactured by any method, and for example, any of those manufactured using electrolytic plating, electroless plating, sputtering, vapor deposition, metal foil, or a clad material can be used.

  Further, the metal layer 10 of the laminated plate SP is formed on the mirror surface plate and peeled off after the production of the wiring board CB, or the metal layer 10 of the laminated plate SP is temporarily attached to the temporary wearing support plate 2 and wiring is performed. It is also possible to peel off after manufacturing the substrate CB. These methods are advantageous in terms of cost and productivity because the wiring board CB can be simultaneously formed on both sides of the temporary wearing support plate 2 and the like (only one side is shown in FIG. 1).

  Regarding the thickness of each layer of the laminated plate SP, for example, the thickness of the metal layer 10 for heat dissipation is 9 to 500 μm (for example, 70 μm), the thickness of the protective metal layer 21 is 1 to 20 μm, and the thickness of the surface metal layer 22 is 10 to 10 μm. 500 μm.

  The above-described electrolytic plating can be performed by a known method. In general, while the target substrate is immersed in a plating bath, it is used as a cathode, and a metal ion replenishment source of a metal to be plated is used as an anode. This is carried out by depositing a metal on the cathode side by an electrolysis reaction.

  On the other hand, for electroless plating, a plating solution such as copper, nickel, or tin can be used. Electroless plating solutions are well known for various metals, and various types are commercially available. In general, the liquid composition contains a metal ion source, an alkali source, a reducing agent, a chelating agent, a stabilizer, and the like. A plating catalyst such as palladium may be deposited prior to electroless plating.

  The metal layer 10 for heat dissipation may be either a single layer or a laminate, and any metal may be used as a constituent metal. For example, copper, copper alloy, aluminum, stainless steel, nickel, iron, other alloys, etc. can be used. . Of these, copper and aluminum are preferable from the viewpoint of thermal conductivity and electrical conductivity. With the structure including the heat-dissipating metal layer 10 having good heat dissipation as described above, the heat dissipation of the light-emitting element 15 can be improved, so that a larger amount of drive current can be supplied and the amount of light emission can be increased. Further, since the thermal resistance can be reduced, luminance can be ensured with low current consumption and low current.

  As the metal constituting the surface metal layer 22, usually copper, copper alloy, nickel, tin or the like can be used, and copper is particularly preferable from the viewpoint of thermal conductivity and electrical conductivity.

  As the metal constituting the protective metal layer 21, a metal different from the heat radiating metal layer 10 and the surface metal layer 22 is used, and another metal exhibiting resistance when etching these metals can be used. Specifically, when these metals are copper, another metal constituting the protective metal layer 21 is gold, silver, zinc, palladium, ruthenium, nickel, rhodium, lead-tin solder alloy, or nickel. -A gold alloy or the like is used. However, the present invention is not limited to the combination of these metals, and any combination with another metal exhibiting resistance when the metal is etched can be used.

  Next, as shown in FIG. 2B, the surface metal layer 22 is selectively etched using the etching resist M. Thereby, the metal penetration part MB is formed in the mounting position of the light emitting element 15. In the present invention, a plurality of metal penetrating parts MB are linearly arranged at the bottom of the wiring board CB. The planar shape of the metal penetration part MB may be any, but it is preferable to increase the area from the viewpoint of heat dissipation.

  In the present embodiment, a metal penetrating part MB having a substantially circular plan view shape is formed, and a substantially circular mounting pad 23b is formed on the upper surface thereof. An electrode portion 23a is formed in the vicinity of the metal penetrating portion MB, and this is electrically connected to the power feeding pattern.

  As the etching resist M, a photosensitive resin, a dry film resist (photoresist), or the like can be used. In addition, when the metal layer 10 for thermal radiation is etched simultaneously with the surface metal layer 22, it is preferable to provide the mask material for preventing this on the lower surface of the metal layer 10 for thermal radiation (in the case of single-sided formation).

  Examples of the etching method include etching methods using various etching solutions according to the types of metals constituting the protective metal layer 21 and the surface metal layer 22. For example, when the surface metal layer 22 is copper and the protective metal layer 21 is the aforementioned metal (including a metal resist), a commercially available alkaline etching solution, ammonium persulfate, hydrogen peroxide / sulfuric acid, or the like can be used. After the etching, the etching resist is removed.

  Next, as shown in FIG. 2D, the exposed protective metal layer 21 is removed. The protective metal layer 21 can be removed by etching. Specifically, when the surface metal layer 22 is copper and the protective metal layer 21 is the above-described metal, nitric acid that is commercially available for removing solder. It is preferable to use an acid-based etching solution such as an acid-based, sulfuric acid-based, or cyan-based acid.

  In this embodiment, next, as shown in FIGS. 2E to 2F, the insulating layer 40 is formed substantially flush with the upper surface of the metal penetration part MB. At this time, after the insulating layer 40 is formed on the formation surface of the metal penetration part MB, the metal penetration part MB can be exposed from the insulation layer 40. Prior to this, the mask M may be removed, but this may be selected as appropriate according to the type of the mask M, such as removal of chemicals and removal of peeling. For example, in the case of photosensitive ink formed by screen printing, it is removed with chemicals such as alkali.

  For forming the insulating layer 40, first, the insulating material 40a is applied. As the insulating material 40a, for example, a reactive curable resin such as a liquid polyimide resin or an epoxy resin that has good insulation properties and is inexpensive can be used. . This may be applied by various methods so as to be slightly thicker than the metal penetrating part MB, and then cured by heating or light irradiation. As a coating method, various coaters such as a curtain coater can be used. Alternatively, a hot pressing or vacuum laminating method may be used using an adhesive sheet, a prepreg, or the like containing a reactive curable resin.

  In the present invention, regarding the insulating layer 40, it is preferable to adopt the same material and thickness as the insulating layer used in the conventional flexible wiring board. That is, the wiring board CB is preferably a curved flexible wiring board. For example, in order to cure the wiring board CB, which is a flexible wiring board, in a curved state, first, a semi-cured flat wiring board CB is prepared and then completely cured by heating using a press die or the like. In addition, the flat wiring board CB can be curved (for example, the state shown in FIG. 1B).

  The insulating layer 40 is preferably made of a white material in order to increase the reflection efficiency. For example, a white epoxy resin, a white prepreg, or the like can be used. In addition, it is possible to increase the reflection efficiency by applying a white resist on the surface.

  Next, the insulating layer 40 having a thickness substantially the same as the height of the metal penetrating part MB is formed by grinding, polishing, or the like of the cured insulating material 40a. Examples of the grinding method include a method using a grinding apparatus having a hard rotary blade in which a plurality of hard blades made of diamond or the like are arranged in the radial direction of the rotary plate, and the hard rotary blade is fixedly supported while rotating. By moving along the upper surface of the wiring board, the upper surface can be planarized. Moreover, as a grinding | polishing method, the method of lightly grind | polishing by a belt sander, buff grinding | polishing, etc. is mentioned.

  As shown in FIG. 2G, the present embodiment includes a step of forming an electrode portion 23a in the vicinity of the metal penetrating portion MB. In the present embodiment, an example is shown in which the mounting pad 23b is formed on the upper surface of the metal penetration part MB, and the power feeding pattern having the electrode part 23a is simultaneously formed in the vicinity of the mounting pad 23b.

  At this time, any pattern forming method may be used, and examples thereof include a panel plating method in which a pattern is formed using an etching resist, and a pattern plating method in which a pattern plating resist is used for plating.

  The power feeding pattern having the mounting pad 23b and the electrode portion 23a is preferably plated with a noble metal such as silver, gold, or nickel in order to increase reflection efficiency. Further, a solder resist may be formed as in the case of a conventional wiring board, or solder plating may be partially performed.

  After the formation of the power supply pattern, the precursor 1 of the wiring board CB is peeled off from the temporary wearing support plate 2 as necessary. Peeling from the temporary attachment state can be performed by mechanical separation from the close contact state or partial temporary attachment by adhesion, and cutting off the partially adhered portion at the time of separation. .

  Further, a resist may be provided on the back surface of the wiring board CB. In that case, in order to improve heat dissipation, it is preferable to leave a portion in which a resist is not formed linearly along the metal layer 10 below the metal penetrating portion MB. Further, it is possible to use a heat radiating resist. In that case, the heat radiating resist can be applied to substantially the entire surface, which is effective in obtaining a rust prevention effect.

  As described above, a flat wiring board CB in which a plurality of wiring boards CB are arranged side by side is manufactured in a state where the insulating layer 40 is semi-cured and then completely cured by heating, using a press die or the like. The flat wiring board CB can be curved as shown in FIG. When the metal layer 10 is provided on the back surface of the wiring board CB, the metal layer 10 has an effect of reinforcing and supporting the insulating layer 40. In that case, a considerably flexible layer can be used as the insulating layer 40.

  As the press mold, a mold (upper mold) having a plurality of ridges along the concave surface of the bowl-shaped wiring board CB and a mold (having a plurality of grooves along the convex surface of the bowl-shaped wiring board CB ( Combination with lower mold).

  The wiring board CB that is curved and formed in a bowl shape on the mounting side of the light emitting element 15 by pressing or the like is obtained as a plurality of wiring boards CB arranged in parallel. As shown in FIG. 4A, the bowl-shaped wiring board CB has a thickness t1 of about 1 to 3 mm, so that the conventional mounting is also applied to the case where a plurality of wiring boards CB are arranged in parallel. The light emitting element 15 can be mounted using an apparatus (a conventional semiconductor mounting apparatus or the like). The pitch of the light emitting elements 15 mounted in a straight line is preferably about 0.7 to 10 mm (for example, 2.5 mm). Note that the light emitting element 15 can be mounted after the wiring substrate CB is divided.

  After the light emitting element 15 is mounted, it is preferable to pot the resin 3 as shown in FIGS. 4A shows a cross-sectional view taken along the arrow A in FIG. 1B (however, the internal cross-section of the wiring board is omitted), and FIG. 4B shows B in FIG. 1B. A cross-sectional view taken in the direction of the arrow is shown.

  4A and 4B, the width W1 of the curved portion of the bowl-shaped wiring board CB is about 2 to 5 mm, and the width W2 of the bowl-shaped wiring board CB including the cutting margin 1b is 3 About 15 mm. The curvature radius of the curved portion of the wiring board CB is preferably about 1.0 to 5.0 mm (for example, 2.5 mm).

  Thus, since the wiring board CB is formed in a bowl shape, the potting can be easily performed because the curved surface has a function of holding the resin when potting the resin 3. As the resin used for potting, a silicon resin, an epoxy resin, or the like can be preferably used. In the potting of the resin 3, it is preferable to form the upper surface in a convex shape from the viewpoint of imparting the function of a convex lens, but the upper surface may be formed in a flat shape or a concave shape. The top surface shape of the potted resin 3 can be controlled by the viscosity of the material used, the coating method, the affinity with the coating surface, and the like.

  FIG. 4B shows an example in which the white resist 4 is formed on the surface of the insulating layer 40. In this example, the white resist 4 is formed so as to be flush with the electrode 23a. The white resist 4 can be formed before the light emitting element 15 is mounted, but the white resist 4 can also increase the reflection efficiency of the light emitting element 15.

  As shown in FIG. 1B, the precursor 1 obtained as described above includes a metal penetration part MB formed at the mounting position of the light emitting element 15, and an insulating layer 40 formed around the metal penetration part MB. And a plurality of light emitting element mounting substrates each having a wiring board CB having an electrode portion 23a formed in the vicinity of the metal penetration part MB and a light emitting element 15 mounted on the wiring board CB. . Each light emitting element mounting substrate is divided | segmented from such a precursor 1. FIG.

  The light emitting element mounting substrate of this invention can be used with the form shown in FIGS. 5-6, for example. FIG. 5 shows a state where the light emitting element mounting substrate T of the present invention is used as a direct type backlight of a liquid crystal display device. A plurality of bowl-shaped wiring substrates CB of the light emitting element mounting substrate T are provided in parallel on the support substrate 5.

  In such an application, the length L1 of the light emitting element mounting substrate T is preferably about 50 to 350 mm (for example, 70 mm), and the pitch P1 is preferably about 3 to 50 mm (for example, 10 mm). Each light emitting element mounting substrate T can be fed using the circuit pattern of the support substrate 5 or the like. It is also possible to electrically connect a plurality of light emitting element mounting substrates T by wiring or the like.

  Further, as a direct backlight of the liquid crystal display device, it is preferable in terms of color reproducibility to use LEDs (RGB) corresponding to the three primary colors of light rather than using white LEDs. The light emitting element mounting substrate of the present invention can also be used as such an RGB type backlight.

  FIG. 7 shows a power supply pattern of an LED chip when the light emitting element mounting substrate of the present invention is used as an RGB backlight (surface layer pattern). In this example, RGB LED chips are electrically connected in series, and every RGB LED chip is arranged every two.

  In this example of the power supply pattern, a mounting pad 23b for bonding the light emitting element 15, an electrode part 23a for performing wire bonding, a wiring part 23c for supplying power to the electrode part 23a, and a wiring part 23c are used. Terminal portion 23d. Note that the width W3 of the power feeding pattern is preferably about 3 to 20 mm.

  A metal penetrating portion MB is formed below the mounting pad 23b, and the metal penetrating portion MB is connected to the metal layer 10 on the back surface (preferably the entire back surface) through a protective metal layer 21 as necessary. .

  Next, FIGS. 6A to 6B show a case where the light emitting element mounting substrate T of the present invention is used as an edge type backlight of a liquid crystal display device. 6A is a perspective view showing a usage state of the light emitting element mounting substrate T, and FIG. 6B is a cross-sectional view taken along the arrow C thereof.

In this type of liquid crystal display device, a light source is provided on the side surface (edge) of the light guide plate 6, but the light emitting element mounting substrate T of the present invention can be used instead of the conventional cathode ray tube. Since the light emitting element mounting substrate T of the present invention is formed in a bowl shape, it improves the reflection efficiency of the light emitting element, can be easily performed even when potting is performed, and is excellent in heat dissipation from the light emitting element. Instead of the cathode ray tube, it can be suitably used.
When the light emitting element mounting substrate T is provided for this purpose, it is possible to adhere to the side surface of the light guide plate 6 using the cutting allowance 1b. However, by utilizing the flexibility of the light emitting element mounting substrate T, FIG. As shown in (b), it is also possible to fit in the side guide portion 7.

  When fitting in the guide part 7, it is effective to provide a locking groove on the inner surface of the guide part 7. Alternatively, the light emitting element mounting substrate T may be formed such that the cutting margin 1b is almost eliminated and the cross section is U-shaped or semicircular.

[Other Embodiments of Manufacturing Method]
(1) In the above-described embodiment, when the insulating layer is formed, the example in which the electrode portion and the like are formed after the insulating layer with the metal penetrating portion exposed is shown. However, in the present invention, as shown in FIG. In addition, a metal layer for forming the electrode portion or the like can be formed integrally with the insulating layer.

  For example, as shown in FIG. 3A, the metal penetration part MB is formed in the same manner as described above. Next, as shown in FIG. 3B, an insulating layer and a metal layer are formed simultaneously using a copper foil with resin. The copper foil with resin is heated and pressed by a pressing surface to obtain a laminated body having a convex portion at a position corresponding to the metal penetrating portion MB and having the metal layer 23 formed on the surface. At this time, it is preferable to arrange at least a sheet material that allows concave deformation between the press surface and the laminated body. Moreover, you may use the press surface which has a recessed part in the position corresponding to metal penetration part MB.

  Various types of copper foil with resin are commercially available, and any of them can be used. Further, the metal layer forming material and the insulating layer forming material may be arranged separately. In this step, since the sheet material is deformed in a concave shape during the heat press due to the presence of the metal penetration part MB, a corresponding convex part is formed in the laminate.

  As a heating press method, a heating / pressurizing apparatus (thermal laminator, heating press) or the like may be used. In this case, the atmosphere may be set to a vacuum (vacuum laminator or the like) in order to avoid air contamination. Conditions such as heating temperature and pressure may be appropriately set according to the material and thickness of the insulating layer forming material and the metal layer forming material, but the pressure is preferably 0.5 to 30 MPa.

  As the insulating layer forming material, any material may be used as long as it is deformed at the time of lamination and molded by heating or the like and has the heat resistance required for the wiring board. Specific examples include various reaction curable resins such as polyimide resins, phenol resins, and epoxy resins, and composites (prepregs) of the same with glass fibers, ceramic fibers, aramid fibers, and the like.

  The sheet material may be any material that allows concave deformation at the time of heating press, such as cushion paper, rubber sheet, elastomer sheet, nonwoven fabric, woven fabric, porous sheet, foam sheet, metal foil, and composites thereof. Can be mentioned. In particular, those that can be elastically deformed, such as cushion paper, rubber sheets, elastomer sheets, foam sheets, and composites thereof, are preferable.

  A release sheet may be additionally arranged together with the sheet material. Examples of the release sheet include a fluororesin film, a silicone resin film, various release papers, a fiber reinforced fluororesin film, and a fiber reinforced silicone resin film.

  The thickness of the sheet material is preferably thicker than half the height of the metal penetrating part MB, and preferably thicker than the height of the metal penetrating part MB. By adjusting the thickness and hardness of the sheet material, it is possible to control the height and shape of the convex portions of the laminate formed by the hot press. Generally, when the thickness of the sheet material is reduced and the hardness is increased, the height and volume of the convex portions of the formed laminate are reduced.

  Next, as shown in FIG. 3C, the convex portions of the laminated body are removed to expose the metal through portions MB. At that time, the portion where the upper surface of the metal penetration MB is higher than the upper surface of the metal layer 23 of the laminate may be removed and planarized at the same time.

  As a method for removing the convex portion, a method by grinding or polishing is preferable, a method using a grinding device having a hard rotary blade in which a plurality of hard blades made of diamond or the like are arranged in the radial direction of the rotary plate, a sander, a belt sander, Examples thereof include a method using a grinder, a surface grinder, a hard abrasive molded product, and the like. When the grinding apparatus is used, the upper surface can be flattened by moving the hard rotary blade along the upper surface of the fixedly supported wiring board while rotating the hard rotary blade. Moreover, as a grinding | polishing method, the method of lightly grind | polishing by a belt sander, buff grinding | polishing, etc. is mentioned. When the convex portion is formed on the laminate as in the present invention, it becomes easy to grind only that portion, and the entire flattening can be performed more reliably.

  Next, the metal layer 23 is etched using an etching resist to form a power feeding pattern having the electrode portions 23a. Thereafter, plating or the like may be performed to increase the thickness of the power feeding pattern or the like.

  (2) In the above-described embodiment, an example in which grinding or the like is performed as it is after directly pressing the resin-coated copper foil is performed. However, in the present invention, after the resin-coated copper foil is heated and pressed, etching of the metal through-hole portion MB is performed. The upper metal layer 23 may be removed, and then grinding or the like may be performed in the same manner.

  (3) In the above-described embodiment, an example in which the metal layer is deformed into a convex shape by arranging a sheet material that allows concave deformation between the press surface and the stacked body has been described. A dry film resist is laminated on the upper surface of the metal layer, and pattern exposure and development are performed to form a dry film resist having an opening above the metal penetration portion. It is also possible to deform the layer into a convex shape.

[Other Embodiments of Light Emitting Element Mounting Board]
(1) In the above-described embodiment, an example in which the face-up type light emitting element is mounted has been described. However, in the present invention, a face-down type light emitting element having a pair of electrodes on the bottom surface may be mounted. In that case, wire bonding or the like may be unnecessary by performing solder bonding or the like.

  (2) In the above-described embodiment, the metal penetrating portion formed at the mounting position of the light emitting element is joined to the metal layer via another protective metal layer exhibiting resistance at the time of etching. Although the example in which the mounting pad is formed on the upper surface is shown, the light-emitting element mounting substrate of the present invention includes a metal through portion formed by etching, an insulating layer formed around the metal through portion, Any structure may be used as long as it has an electrode part formed in the vicinity of the metal penetration part.

  For example, the protective metal layer can be omitted by configuring the metal penetration part MB and the metal layer 10 with different metals. In that case, it is preferable to form the metal penetration part MB with the same metal as the protective metal layer mentioned above. Such a metal penetrating part MB can be formed by stopping the etching with the metal layer 10 when performing the etching, as in the above-described embodiment.

  Moreover, as shown in FIG.1 (c), it is also possible to abbreviate | omit a protective metal layer by comprising the metal penetration part MB and the metal layer 10 with the same metal. In that case, the metal penetration part MB (the metal penetration part 22b after etching) can be formed by etching (half-etching) the metal plate having the thickness of the metal penetration part MB and the metal layer 10 together. .

  In the example shown in FIG. 1C, only the bottom portion of the wiring board CB is made flat so that the light emitting element 15 can be easily mounted (mounted), and the remaining curved portion has a curved section. An example of bending is shown. Thus, when the bottom part of the wiring board CB has a flat part, there is an advantage that the optical axis direction of the light emitting element 15 can be easily oriented in the direction perpendicular to the wiring board CB (directivity). The width in the cross section of the plane portion is preferably about 0.3 to 0.5 mm.

  Furthermore, the light emitting element 15 may be mounted on the metal penetration MB without forming a mounting pad. In this case, the light emitting element 15 is bonded to a lower position by the thickness of the electrode portion 23a. Further, an adhesive layer, a pressure-sensitive adhesive layer, a heat-dissipating sheet, or the like may be interposed between the wiring substrate CB having the metal penetration part MB and the metal layer 10.

  (3) In the above-described embodiment, the example in which the light emitting element is mounted on the wiring substrate having a single wiring layer is shown. However, in the present invention, light emission is performed on a multilayer wiring substrate having two or more wiring layers. An element may be mounted. In that case, the conductive connection structure between the wiring layers can be formed in the same process as the process of forming the metal penetration portion. Details of the method of forming such a conductive connection structure are described in International Publication No. WO 00/52977, and any of these can be applied.

It is a figure which shows an example of the light emitting element mounting substrate of this invention, (a) is sectional drawing perpendicular | vertical to a longitudinal direction, (b) shows the perspective view before a division | segmentation, (c) is the light emitting element mounting substrate of this invention. Sectional view perpendicular to the longitudinal direction showing another example Process drawing which shows an example of the manufacturing method of the light emitting element mounting substrate of this invention Process drawing which shows the other example of the manufacturing method of the light emitting element mounting substrate of this invention. 1 shows an example of a light-emitting element mounting substrate of the present invention, (a) shows a cross-sectional view taken along arrow A in FIG. 1 (b), and (b) shows a view taken along arrow B in FIG. 1 (b). Cross section The top view which shows the example of the state in which the light emitting element mounting substrate of this invention was used as a direct type backlight of a liquid crystal display device It is a figure which shows the example of the state in which the light emitting element mounting substrate of this invention was used as an edge type backlight of a liquid crystal display device, (a) is a perspective view which shows the use condition of the light emitting element mounting substrate T, (b) ) Is a cross-sectional view of the arrow C The top view which shows the electric power feeding pattern of the LED chip of the example in the case of using the light emitting element mounting substrate of this invention as a RGB type backlight

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Metal layer 15 Light emitting element 21 Protective metal layer 22 Surface metal layer 23a Electrode part 23b Mounting pad 40 Insulating layer CB Wiring board MB Metal penetration part

Claims (7)

A metal penetrating portion formed at a mounting position of the light emitting element ; a metal layer formed by etching the metal penetrating portion; an insulating layer formed around the metal penetrating portion on the metal layer; and the metal penetrating portion. A light emitting element mounting substrate comprising: a wiring board having an electrode portion formed in the vicinity of the part; and a light emitting element mounted on the wiring board,
The wiring board is a flexible wiring board that is bent in a bowl shape on the light emitting element mounting side, and a plurality of the metal through portions are linearly arranged at the bottom of the wiring board. substrate. The light emitting element mounting substrate according to claim 1 , wherein a white resist is provided on a surface of the wiring substrate. The light emitting element mounting substrate according to claim 1, wherein the light emitting element mounted on the wiring board is potted with resin . A metal penetrating portion formed at a mounting position of the light emitting element ; a metal layer formed by etching the metal penetrating portion; an insulating layer formed around the metal penetrating portion on the metal layer; and the metal penetrating portion. A light-emitting element mounting substrate comprising a wiring substrate having an electrode portion formed in the vicinity of the portion,
The wiring board is a flexible wiring board formed in a bowl shape curved toward the mounting side of the light emitting element, and a plurality of the metal through portions are linearly arranged at the bottom of the wiring board. substrate. A metal penetrating portion formed at a mounting position of the light emitting element ; a metal layer formed by etching the metal penetrating portion; an insulating layer formed around the metal penetrating portion on the metal layer; and the metal penetrating portion. A light-emitting element mounting substrate comprising a wiring substrate having an electrode portion formed in the vicinity of the portion,
The wiring board is a flexible wiring board formed in a bowl shape curved toward the mounting side of the light emitting element, and has a structure in which a plurality of bowl-like wiring boards are arranged side by side, and a plurality of the metal penetrating portions are provided. A light-emitting element mounting substrate arranged in a straight line at the bottom of the wiring substrate.   The manufacturing method of the light emitting element mounting substrate including the process of dividing | segmenting each light emitting element mounting substrate from the precursor in which the light emitting element mounting substrate in any one of Claims 1-3 was arranged in parallel.   A step of mounting a light emitting element on a plurality of the wiring boards according to any one of claims 1 to 3 and a step of dividing each light emitting element mounting substrate from a precursor obtained in the step. The manufacturing method of the light emitting element mounting substrate containing.

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