JP4945416B2 - Light emitting module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a light emitting module and a method for manufacturing the same.

  When a semiconductor light emitting device is used instead of a cold cathode tube or a fluorescent lamp as a backlight light source for a liquid crystal display device or the like, power saving, long life, high reliability, and miniaturization are facilitated. In this case, a thin side-view type light emitting device can be used as a backlight light source for a small liquid crystal display device of a cellular phone.

  In addition, a top-view light-emitting device having a narrow width can be used as a backlight light source for a medium-sized liquid crystal display device such as car navigation. In a liquid crystal display device having a medium-sized or larger screen, the light from the backlight source can be uniformly spread over the entire liquid crystal display screen by using a light guide plate. In this case, if the light from the light emitting device is not radiated in the same direction with respect to the mounting substrate to which the plurality of light emitting devices are attached, uneven brightness of the display screen is likely to occur.

There is a technical disclosure example regarding a light emitting element storage package and a light emitting device that can be accurately mounted on a wiring conductor of a circuit board without positional deviation or inclination (Patent Document 1). In this technical disclosure example, a circular external connection electrode, a connection conductor having a width narrower than the diameter, and a light emitting element mounting portion are formed on the lower surface of the package base so as to overlap in plan view. And a metal layer.
However, in the light emitting module in which the light emitting device according to this technical disclosure example is incorporated on the mounting substrate, it is not easy to reduce the angular deviation in the direction of the emitted light from the light emitting device.
JP 2005-191203 A

  Provided are a light emitting module capable of reducing an angular shift in a direction of emitted light with respect to a mounting substrate, and a manufacturing method thereof.

  According to one aspect of the present invention, a light emitting element, an anode electrode electrically connected to the anode of the light emitting element, a cathode electrode electrically connected to the cathode of the light emitting element, and a mounting pad portion , A first conductive part electrically connected to the anode electrode, a second conductive part electrically connected to the cathode electrode, and the mounting pad part. A mounting substrate having a third conductive portion, wherein the anode electrode, the cathode electrode, and the mounting pad portion are disposed along a common first direction in a plan view, and The conductive portion, the second conductive portion, and the third conductive portion are disposed along a common second direction in plan view, and the light emitting device and the mounting substrate are arranged in plan view. Connect so that the direction of 1 and the second direction match In the lateral direction substantially orthogonal to the first and second directions, the length of the third conductive portion is smaller than the length of any of the first and second conductive layers, and the anode electrode , The cathode electrode and the mounting pad portion or less than the minimum length, or in the lateral direction, the length of the mounting pad portion is the length of either the anode electrode or the cathode electrode. There is provided a light emitting module that is smaller than the first length and is not longer than a minimum length of the first conductive portion, the second conductive portion, and the third conductive portion.

  According to another aspect of the present invention, there is provided a method for manufacturing the light emitting module, wherein at least one of a solder material and a conductive adhesive is provided on at least one side of the light emitting device and the mounting substrate. And applying at least one of the solder material and the conductive adhesive, and the light emitting device and the conductive substrate are restrained from being inclined with respect to the mounting substrate. There is provided a method for manufacturing a light emitting module, comprising the step of adhering to a mounting substrate.

  Provided are a light-emitting module and a method for manufacturing the same that can reduce the angular deviation in the direction of emitted light with respect to a mounting substrate.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating a light emitting module according to a first embodiment of the present invention. The light emitting module includes a light emitting device and a mounting substrate. 1A is a top view of the light emitting device, FIG. 1B is a bottom view, and FIG. 1C is a partial cross-sectional view and a partial side view taken along the line AA. 1D is a top view of the mounting substrate, and FIG. 1E is a cross-sectional view taken along the line BB.

  The light emitting element 12 is made of, for example, a nitride-based semiconductor material, and emits light having a wavelength band of, for example, 380 to 550 nm. The light emitting element 12 is mounted on the package 11 and constitutes the light emitting device 10. The package 11 includes a base body 11a made of an insulator such as ceramic, a frame body 11b that forms a recess 11c filled with a sealing resin, and an anode electrode 14 (14a, 14a, electrically connected to the anode of the light emitting element 12). 14b, 14c), a cathode electrode 15 (15a, 15b, 15c) electrically connected to the cathode, and a mounting pad portion 16 provided on the lower surface of the package 11.

  The anode electrode 14 includes 14a provided on the upper surface of the base body 11a, 14b provided on the lower surface of the base body 11a, and 14c on the surface of the notch portion provided on the side corner of the base body 11a. Moreover, the cathode electrode 15 includes 15a provided on the upper surface of the base 11a, 15b provided on the lower surface of the base 11a, and 15c on the surface of the notch provided on the side corner of the base 11a. The anode of the light emitting element 12 is electrically connected to the anode electrode 14a by the bonding wire 13, and the cathode of the light emitting element 12 is bonded to the cathode electrode 15a to be electrically connected.

  In addition, the cathode electrode 14 and the anode electrode 15 are not limited to this structure, For example, a reverse arrangement relationship may be sufficient by planar view. Further, when the back surface of the light emitting element 12 is insulated, the two electrodes on the front surface side, the anode electrode 14 and the cathode electrode 15 may be connected by bonding wires.

  When the sealing resin in which the phosphor is dispersed is filled in the recess 11c of the package 11, visible light or white light by mixing visible light can be obtained. The size of the package 11 is 4 mm × 2 mm, for example. When used as a backlight light source, the display device can be thinned by reducing the width of the package 11.

  On the lower surface of the light emitting device 10, as shown in FIG. 1B, an anode electrode 14b, a cathode electrode 15b, and a mounting pad portion 16 are arranged. If the substrate 11a is ceramic, these patterns can be formed using a metallized layer. The anode electrode 14b, the cathode electrode 15b, and the mounting pad portion 16 are arranged along the direction of the first symmetry axis 18 that is common to each other in plan view. The lateral width (length) substantially orthogonal to the direction of the first axis of symmetry 18 is P1 for the anode electrode 14b, P2 for the cathode electrode 15b, and P3 for the mounting pad 16. P1, P2, and P3 can each be equal to or smaller than the width WP of the package 11 and need not be the same. Note that, when the anode electrode width P1 and the cathode electrode width P2 are close to the lateral width WP of the light emitting device 10, the electrical contact with the conductive portion of the mounting substrate 30 can be ensured and the adhesive strength can be increased.

  The mounting substrate 30 to which the light emitting device 10 is bonded is, for example, a glass epoxy substrate. A first conductive portion 34, a second conductive portion 35, and a third conductive portion 36 are patterned on one surface of the mounting substrate 30, respectively. In the light emitting device 10 and the mounting substrate 30, the anode electrode 14 b is a first conductive portion 34, the cathode electrode 15 b is a second conductive portion 35, and the mounting pad portion 16 is a third conductive portion 36. Glued by etc.

  Further, the first conductive portion 34, the second conductive portion 35, and the third conductive portion 36 are arranged along the direction of the second symmetry axis 38 that is common to each other in plan view. Further, the lateral width (length) substantially orthogonal to the direction of the second symmetry axis 38 is set to B1 in the first conductive portion 34, B2 in the second conductive portion 35, and B3 in the third conductive portion 36. And Note that it is preferable to use a solder material or the like so that the directions of the first and second symmetry axes 18 and 38 substantially coincide with each other because the radiation patterns and optical axes of the plurality of light emitting devices 10 can be made uniform.

  FIG. 2 is a schematic diagram illustrating the light emitting module according to the present embodiment. 2 (a) is a top view, FIG. 2 (b) is a cross-sectional view along the line DD, FIG. 2 (c) is a cross-sectional view along the line CC, and FIG. 2 (d) is the surface tension. It is a figure showing an effect | action.

2A, in the mounting substrate 30, the width B3 of the third conductive portion 36 is narrower than both the width B1 of the first conductive portion 34 and the width B2 of the second conductive portion 35, and the anode. The width is equal to or less than the minimum of the width P1 of the electrode 14b, the width P2 of the cathode electrode 15b, and the width P3 of the mounting pad portion 16. That is, (Expression 1) to (Expression 3) are established.

B3 <B1 (Formula 1)
B3 <B2 (Formula 2)
B3 ≦ min {P1, P2, P3} (Formula 3)
However, min represents the minimum value among P1, P2, and P3.

In this case, there is no adhesive pattern having a width smaller than the width B3 of the third conductive portion 36.

  As shown in FIG. 2D, the melted solder material 40 has a width substantially equal to B3, and the cross-section rises in an arc shape due to surface tension. However, since the width of the solder material 40 is narrow, the lower end of the package 11 can be prevented from shifting to both ends Q of the solder material 40, and the positional shift to the left and right can be reduced as compared with the electrode region where the width of the solder material 40 is wide. . That is, as shown in FIG. 2C, the center position of the light emitting device 10 is controlled with a good left-right stress balance near the second symmetry axis 38 by the surface tension of the molten solder material 40, and the light emitting device 10, the mounting substrate 30, and the like. Can be bonded while maintaining a stable state in which they are substantially parallel. For this reason, the angular deviation of the optical axis G of the radiated light represented by a broken line can be reduced. In addition, if the width B3 of the mounting pad portion 16 is narrowed within a range in which the adhesive strength can be maintained, the control of the center position of the package 11 is facilitated.

  FIG. 3 is a schematic diagram illustrating a light emitting module according to a comparative example. FIG. 3A is a schematic top view, FIG. 3B is a schematic cross-sectional view along the line FF, and FIG. 3C is a diagram showing the action of surface tension. In this comparative example, the mounting pad portion is not provided in the light emitting device 110. The mounting substrate 130 is provided with a first conductive portion 134 bonded to the anode electrode 114b and the solder material 140, and a second conductive portion 135 bonded to the cathode electrode 115b and the solder material 140. As shown in FIG. 3C, the solder material 140 spreads in the lateral direction and has an arcuate cross section due to surface tension. For this reason, the light emitting device 110 is likely to move greatly along the arrow direction.

  In this case, the end of the light emitting device 110 may move to the vicinity of the end R of the solder material 140 and be fixed in an inclined state as shown in FIG. In this case, the light emitting device 110 is inclined with respect to the mounting substrate 130, and the optical axis G of the emitted light has an angular deviation θ with respect to the mounting substrate 130. In a light emitting module in which a plurality of light emitting elements 110 are arranged, the degree of this angular deviation varies from package to package, and the light intensity distribution becomes uneven. For this reason, the luminance unevenness of the display screen occurs in the backlight light source application.

  On the other hand, in the present embodiment, a mounting pad portion 36 having a narrow width is provided to control the center position of the light emitting element 10 to reduce the positional deviation. As the width WP of the light emitting device 10 becomes narrower, positional deviation is more likely to occur, so the effect of this embodiment becomes greater. For this reason, when a backlight light source having a plurality of light emitting devices 10 is used, it becomes easy to suppress uneven luminance of the display screen.

  The mounting pad portion 16 is not limited to being provided between the anode electrode 14b and the cathode electrode 15b. However, when the mounting pad portion 16 is arranged in the middle as shown in FIG. 2, a large misalignment caused by the wide molten solder 40 on the anode electrode 14b side and the cathode electrode 15b side is balanced at the middle position. It is more preferable because it can be controlled well and the displacement of the light emitting device 10 can be effectively reduced.

In FIG. 2A, (Expression 4) and (Expression 5) can be established.
P1 ≦ WP ≦ B1 (Formula 4)
P2 ≦ WP ≦ B2 (Formula 5)

 As described above, when the width (length) of the conductive portion of the mounting substrate 30 is equal to or larger than the lateral width (length) WP of the light emitting device 10, the soldering performance is inspected and mounting can be ensured.

   Furthermore, since the mounting pad portion 16 is connected to the third conductive portion 36 of the mounting substrate 30, the heat generated in the light emitting element 12 is easily radiated through the mounting substrate 30.

  FIG. 4 is a schematic view of a light emitting module according to the second embodiment. 4A is a top view of the light emitting device, and FIG. 4B is a bottom view. 4 (c) is a top view of the mounting substrate, FIG. 4 (d) is a cross-sectional view along the line EE, FIG. 4 (e) is a view before bonding, and FIG. 4 (f) is after bonding. FIG.

In the present embodiment, the angle deviation is reduced by the mounting pad portion 16 of the light emitting device 10. That is, (Expression 6) to (Expression 8) are established.
P3 <P1 (Formula 6)
P3 <P2 (Formula 7)
P3 ≦ min {B1, B2, B3} (Formula 8)
However, min is the minimum value among B1, B2, and B3.
In this case, there is no adhesive pattern having a width narrower than the width P3 of the mounting pad portion 16.

  FIG. 4E shows a transverse cross section when the mounting pad portion 16 and the third conductive portion 36 are soldered. The width of the molten solder material 40 is approximately P3, and the width of the light emitting device 10 is shown. The amount of misalignment in the direction can be suppressed. That is, as shown in FIG. 4 (f), the center position of the light emitting device 10 can be controlled in the vicinity of the second symmetry axis 38 by the surface tension of the solder material 40, and the optical axis G of the emitted light and the vertical direction of the mounting substrate 30 And the angular deviation between the two can be reduced. Further, when P1 ≦ WP ≦ B1 and P2 ≦ WP ≦ B2, the performance of soldering is inspected and mounting can be performed more reliably.

  In FIG. 4E, the solder material 40 is applied to the mounting pad portion 16, but the present invention is not limited to this. Even if the solder material 40 is applied to the third conductive portion 36, the width P3 of the mounting pad portion 16 is narrow as shown in (Expression 6) to (Expression 8). The surface tension can be controlled in the vicinity of the second symmetry axis 38. In addition, although the case where the solder material 40 was used was demonstrated in 1st and 2nd embodiment, this invention is not limited to this. In the case where the liquid conductive adhesive is cured and bonded, misalignment based on surface tension can be similarly reduced.

    5A and 5B show a modification of the light emitting device used in the light emitting module according to the present embodiment. FIG. 5A is a schematic top view and FIG. 5B is a schematic bottom view. An anode electrode 14b or a cathode electrode 15b provided on the lower surface of the package 11 is connected to the mounting pad portion 16 by a wiring layer 17 having a narrow width.

  When the substrate 11a is ceramic, the anode electrode 14b and the cathode electrode 15b can be formed by metallization using a thick film, for example. In this case, when an Au thin film or the like is formed on the surface of the thick film by electroplating, the surface is protected and oxidation is prevented, and the wettability of the solder material can be improved. In this way, a highly reliable light emitting module can be mounted in a short time using a reflow soldering process.

  FIG. 6 is a flowchart of the manufacturing method of the light emitting module according to the present embodiment. In FIG. 1, on the side of the anode electrode 14b, the cathode electrode 15b, and the mounting pad portion 16 of the light emitting device 10, or the first conductive portion 34, the second conductive portion 35, and the third conductive portion of the mounting substrate 30. The solder material 40 or the conductive adhesive is applied to at least one of the 36 sides using a printing method or the like (S100).

  The positions of the anode electrode 14b and the first conductive portion 34, the cathode electrode 15b and the second conductive portion 35, and the mounting pad portion 16 and the third conductive portion 36 are aligned. In the case where a plurality of light emitting devices 10 are arranged, it is easy to align the optical axis G if the first symmetry axis 18 of the light emitting device 10 and the second symmetry axis 38 of the mounting substrate 30 are matched (S102). ).

  When using the solder material 40, the heating temperature of the reflow furnace is set to be higher than the melting point of the solder material 40 and the reflow furnace is passed in a short time, whereby the light emitting device 10 can be bonded while maintaining the good characteristics. When a conductive adhesive is used, the adhesive is cured by heat or UV irradiation (S104). If the width of the conductive portion of the mounting substrate 30 is wider than the width WP of the light emitting device 10, it is possible to reliably bond and confirm the bonded portion, facilitating quality control. In the case of the light emitting module 5 in which a large number of the light emitting devices 10 are arranged, it is preferable to ensure reliability by doing so.

  Next, the electrical and optical characteristics are measured, and the light emitting module 5 is cleaned (S106).

  The third conductive portion 36 provided on the mounting substrate 30 is not limited to a rectangular shape. FIG. 7 is a schematic diagram of a modified example according to the light emitting module of the first embodiment. As shown in FIG. 7D, the third conductive portion 36 has an elliptical shape with a major axis of B3. The shape may be a polygon. By adhering the third conductive portion 36 having such a shape to the mounting pad portion 16, it is possible to reduce the angular deviation in the direction of the emitted light.

  FIG. 8 is a schematic view of a modified example according to the light emitting module of the second embodiment. The mounting pad portion 16 in FIG. 8B has an elliptical shape with a major axis of P3. The shape may be a polygon. By bonding the mounting pad portion 16 having such a shape to the third conductive portion 36, the angular deviation in the direction of the emitted light can be reduced.

  FIG. 9 is a schematic diagram illustrating an application example of the light emitting module according to the present embodiment. The light emitting module 5 in which eight light emitting devices 10 are arranged can be used as a backlight light source of a liquid crystal display device. Radiant light having a uniform optical axis direction is incident from the side surface 60 c of the light guide plate 60 from the light emitting module 5.

  Incident light is reflected by the light scattering surface 60b, which is the lower surface of the light guide plate 60, and exits from the light emitting surface 60a. A liquid crystal display plate 62 is provided above the light guide plate 60, and light from the light emitting surface 60a enters. The inclination of the optical axis of the light emitting device 10 according to the present embodiment is reduced, and the liquid crystal display panel 62 can be evenly irradiated, and the luminance unevenness is reduced. In particular, it is easy to improve image quality in a liquid crystal display device having a medium size or larger.

  Increasing the number of light emitting devices 10 can increase the light intensity of the backlight source. Further, when the arrangement interval of the light emitting devices 10 is narrowed, it becomes easy to make the luminance uniform. For example, in the case of a car navigation liquid crystal display device, 15 to 20 light emitting devices 10 are arranged.

  As another application example, there is a display device having a light emitting module in which the light emitting devices 10 are two-dimensionally arranged. By arranging the light emitting devices 10 with reduced angular deviation, a full color display device with reduced luminance unevenness or the like can be realized.

  The base body 11a and the frame body 11b of the package 11 of the light emitting device 10 are not limited to ceramic. A package in which the anode electrode, the cathode electrode, and the mounting pad portion are made of a metal material, and these metal material components are embedded in a resin molded body with a resin material may be used. Moreover, it is good also as an electrode by forming a conductive layer by the metallization etc. on the surface of a resin molding. Whether the material constituting the package is ceramic or resin, the surface mounting type is more preferable because the light emitting module 5 can be made small and thin.

  The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to these embodiments. Even if a person skilled in the art has changed the design regarding the material, shape, size, arrangement, etc. of the light emitting device, the mounting substrate, the electrode, the conductive portion, and the mounting pad portion constituting the present invention, the gist of the present invention is achieved. Unless it deviates, it is included in the scope of the present invention.

Schematic diagram of light-emitting elements and mounting board that make up light-emitting module The schematic diagram showing the light emitting module concerning 1st Embodiment Schematic diagram illustrating a light emitting module according to a comparative example Schematic diagram of the light emitting module according to the second embodiment Schematic diagram showing a modification of the light emitting device Flow chart of manufacturing method of light emitting module The schematic diagram showing the light emitting module concerning the modification of 1st Embodiment Schematic showing the light emitting module concerning the modification of 2nd Embodiment. Schematic diagram showing application examples of light emitting modules

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Light emitting module, 10 Light emitting device, 11 Package, 12 Semiconductor element, 14 Anode electrode, 15 Cathode electrode, 16 Mounting pad part, 17 Wiring layer, 18 1st symmetry axis, 30 Mounting board, 34 1st electroconductive part , 35 second conductive portion, 36 third conductive portion, 38 second symmetry axis, 40 solder material, P1 anode electrode width, P2 cathode electrode width, P3 mounting pad portion width, B1 first conductive portion width , B2 second conductive part width, B3 third conductive part width, WP width of light emitting device, G optical axis

Claims (5)

A light emitting device comprising: a light emitting element; an anode electrode electrically connected to an anode of the light emitting element; a cathode electrode electrically connected to a cathode of the light emitting element; and a mounting pad portion;
A first conductive part electrically connected to the anode electrode, a second conductive part electrically connected to the cathode electrode, a third conductive part connected to the mounting pad part, A mounting board having
With
The anode electrode, the cathode electrode, and the mounting pad portion are arranged along a common first direction in a plan view,
The first conductive portion, the second conductive portion, and the third conductive portion are disposed along a common second direction in plan view,
The light emitting device and the mounting substrate are connected so that the first direction and the second direction coincide with each other in plan view,
In the lateral direction substantially orthogonal to the first and second directions, the length of the third conductive portion is smaller than any length of the first and second conductive layers, and the anode electrode, It is less than the minimum length of the cathode electrode and the mounting pad part,
Alternatively, in the lateral direction, the length of the mounting pad portion is shorter than any of the anode electrode and the cathode electrode, and the first conductive portion, the second conductive portion, and the third conductive portion. A light emitting module having a length equal to or shorter than a minimum length of the conductive parts.   2. The light emitting module according to claim 1, wherein in the lateral direction, a length of the first and second conductive portions is equal to or longer than a length of the light emitting device.   The light emitting module according to claim 1, wherein the mounting pad portion is electrically connected to the anode electrode or the cathode electrode through a wiring layer.   The light emitting module according to claim 1, wherein the mounting pad portion is provided between the anode electrode and the cathode electrode. It is a manufacturing method of the light emitting module as described in any one of Claims 1-4,
Applying at least one of a solder material and a conductive adhesive to at least one side of the light emitting device and the mounting substrate;
The step of bonding the light emitting device and the mounting substrate while suppressing at least one of the solder material and the conductive adhesive from rising due to surface tension and tilting the light emitting device with respect to the mounting substrate. When,
A light emitting module manufacturing method comprising:

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