JP5248449B2 - Light emitting device - Google Patents

Description

  The present invention relates to a backlight device used in, for example, a mobile phone, a digital camera, or a portable game machine, and a light emitting device used in a liquid crystal display device.

  In recent mobile devices such as PDAs, mobile phones, and notebook PCs, mounting of a display device with a touch panel that can be operated by touching the screen with a finger or a pen is becoming mainstream. In the mobile devices as described above, portability is usually improved by using a liquid crystal panel having features such as thinness and light weight for a display portion for displaying information.

  However, at present, these touch panels are mainly external type such as a resistive film type and a capacitance type, and there are still problems such as a large frame and an increased thickness. Therefore, the development of a display device of a type in which a touch panel function is incorporated in the display device, which can be thinned and narrowed in frame instead of an external touch panel, has been activated. Among these, as a method for detecting the touch position in the display screen, a method is known in which a plurality of optical sensors are provided on the display panel and a shadow image formed when a finger or the like approaches the screen is detected by the optical sensor. In this method of detecting an image, when the illuminance of outside light is low (the surroundings are dark), it becomes difficult to distinguish the image from the background in the image obtained by the optical sensor, and the touch position cannot be detected accurately. Sometimes.

  Therefore, for a display device provided with a backlight device, a method is also known in which a reflected image when the illumination light of the backlight device hits a finger or a pen is detected by an optical sensor (for example, Patent Document 1).

  On the other hand, as a light source used in the backlight device, an edge light type light source using an LED as shown in Patent Document 2 is known. The edge light type light source has a configuration in which light from the light source is introduced from the side surface of the light guide plate disposed at the lower part of the liquid crystal panel, and the entire display device can be thinned. For this reason, the edge light type light source is often used for a small-sized liquid crystal panel attached to a portable terminal or the like.

JP 2008-262204 A (released on October 30, 2008) JP 2007-59231 A (published March 8, 2007)

  However, in the conventional display device as described above, there is no description about the structure of the light source part, and when the surrounding environment becomes bright, the reflected image of the finger and the background by the ambient light in the image obtained by the optical sensor There was a problem that it became difficult to distinguish. That is, the conventional display device may have a problem that sufficient detection accuracy cannot be ensured due to the adverse effect of the surrounding environment.

  In order to enable operation in a bright environment as described above, it is conceivable to improve the light intensity of the backlight device. However, a backlight device equipped with a single-type light emitting diode, which is currently mainstream, can be used. When the light source is used, it is necessary to mount a large number of light emitting diodes, which causes a new problem that it is difficult to make the display device thinner and narrower.

  When such an edge light type light source employs a touch panel system in which a reflected image is detected by an optical sensor when the illumination light of the backlight device hits a finger or a pen, as in Patent Document 1, the backlight device Then, a white LED for backlight and an infrared LED for optical sensor are mounted.

  However, in the backlight light-emitting device provided with such two types of LEDs individually, the mounting of the LEDs and the wiring between the LEDs become complicated. In addition, it is necessary to devise in order to eliminate variations in luminous intensity between infrared light and white light.

  An object of the present invention is to provide infrared light and white light, which are suitable as a light source for a backlight of a display device that also serves as a touch panel, and in-plane uniformity of the emission intensity of white light and infrared light inside the backlight. Both are to provide a high light emitting device.

In order to solve the above problems, the present invention includes a substrate, and a plurality of white LEDs and a plurality of infrared LEDs arranged linearly on the substrate, and the white LEDs and the infrared LEDs are: Alternatingly arranged , the infrared LEDs are arranged at both ends of the substrate.

In the light-emitting device configured as described above, in a line-shaped light-emitting device in which two types of light sources are arranged on a straight line, it is possible to reduce the intensity variation of infrared light and white light in the column direction (linear direction). it can. Accordingly, the light emitting device can be made lightweight and compact, and at the same time, the light amount emitted from the light source device located at the center portion and the light source located at the end portion in the direction of the row where the light source devices of different kinds of light are arranged The difference from the amount of light emitted from the apparatus can be reduced, and more uniform light can be emitted in the column direction. Further, the infrared light distribution from the light emitting device can be made uniform by arranging the infrared LEDs at both ends of the light emitting device.

  The white LED may include a light emitting element that emits primary light and a phosphor that absorbs the primary light and emits secondary light.

  The infrared LEDs may be electrically connected in series, and the white LEDs may be electrically connected in series.

  An external connection terminal that supplies electricity to the white LED and the infrared LED may be provided at an end of the substrate. In particular, the external connection terminal may be provided at one end of the substrate. Thereby, since it is an edge part of a light-emitting device that divides | segments a metal layer in the case of board | substrate division | segmentation, the burr | flash and curvature at the time of division | segmentation can be reduced.

  At least one end of the external connection terminal may be formed to the long side of the light emitting device. As a result, the wettability and scooping of the solder during reflow soldering are improved.

  The white LED is covered with a first resin body, the infrared LED is covered with a second resin body, and white high ends are provided at both ends of the first resin body and the second resin body. It can be set as the structure in which the reflectance photoresist is formed. Thereby, the wall (resin dam) of the 1st resin body and the 2nd resin body can be formed by a simple method and an easy method.

  The substrate may be configured such that a wiring pattern for electrically connecting white LEDs and a wiring pattern for electrically connecting infrared LEDs are formed on the upper and lower surfaces of the substrate.

  A wiring through hole may be formed inside the substrate.

  The said board | substrate can be set as the structure which consists of the laminated substrate which laminated | stacked the base material made from a bismaleimide triazine resin.

  The said board | substrate can be set as the structure which is a multilayer substrate which laminated | stacked the upper layer base material, the core base material, and the lower layer base material. Thus, by using a multilayer substrate, wiring through-holes can be formed in each layer, and a wiring pattern can be formed between the substrates.

  The upper layer base material, the core base material, and the lower layer base material may have a through hole for wiring.

  A wiring pattern for the infrared LED and the white LED and an external connection terminal for the infrared LED and the white LED can be formed on the surface of the upper layer base material.

  A wiring pattern for electrically connecting the white LED may be formed on the surface side of the substrate, and the through hole and the wiring pattern may be electrically connected.

  A wiring pattern for electrically connecting the infrared LED and the external connection terminal of the infrared LED may be formed on the back side of the substrate.

  A heat radiating post penetrating the substrate may be formed below the mounting portion of the white LED and the infrared LED on the substrate. Thereby, the heat which arises at the time of operation | movement of the said white LED and the said infrared LED can be thermally radiated from a board | substrate back surface via a thermal radiation post | mailbox.

  A through hole for wiring is formed inside the substrate, and the heat dissipation post and the through hole can be made of the same material. Thereby, the increase in the process for heat dissipation post formation can be avoided.

According to the present invention, in a line-shaped light emitting device in which a plurality of light sources are arranged on a straight line, it is possible to reduce the intensity variation of infrared light and white light in the column direction (linear direction). Accordingly, the light emitting device can be made lightweight and compact, and at the same time, the light amount emitted from the light source device located at the center portion and the light source located at the end portion in the direction of the row where the light source devices of different kinds of light are arranged The difference between the amount of light emitted from the device and the effect of being able to emit more uniform light in the column direction , and the arrangement of infrared LEDs at both ends of the light emitting device As a result, the distribution of infrared light from the light emitting device can be made uniform .

The top surface schematic diagram which shows one light-emitting device concerning this invention is shown. The back surface schematic diagram which shows one light-emitting device concerning this invention is shown. The side surface schematic diagram which shows one light-emitting device concerning this invention is shown. (A) is a schematic top view of a wiring pattern according to the present invention, and (b) is a schematic top view (enlarged view) of the wiring pattern according to the present invention. The arrangement plan of white LED and infrared LED concerning the present invention is shown. The wiring inner layer pattern sectional drawing of the board | substrate concerning this invention is shown. The upper surface schematic diagram which shows the chip | tip arrangement | positioning figure concerning this invention is shown. The board | substrate schematic diagram after 1st resin application | coating is shown. The cross-sectional schematic diagram after 1st resin and 2nd resin application | coating is shown. The board | substrate schematic diagram after 2nd resin application | coating is shown. The schematic diagram of the display apparatus combined with a touch panel using the light-emitting device of the present invention is shown. FIG. 2 shows a light emitting device according to a second embodiment, where (a) is a top view, (b) is a bottom view, and (c) is a cross-sectional view. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic diagram of the wiring pattern concerning Embodiment 1, (a) is a top view of a part of board | substrate, (b) is an enlarged view of the external connection terminal part, (c) is the light-emitting device divided | segmented separately It is an enlarged view of the external connection terminal part. It is sectional drawing which shows the mounting structure to the mounting substrate of the said light-emitting device. FIG. 6 is a schematic diagram of a wiring pattern according to a third embodiment, where (a) is an enlarged view of an external connection terminal portion, and (b) is an enlarged view of an external connection terminal portion of a light-emitting device divided individually. FIG. 9 is a schematic diagram of another wiring pattern according to the third embodiment, where (a) is an enlarged view of an external connection terminal portion, and (b) is an enlarged view of an external connection terminal portion of a light-emitting device that is individually divided. FIG. 6 is a cross-sectional view showing a light emitting device according to a fourth embodiment. FIG. 6 is a bottom view showing a light emitting device according to a fourth embodiment. It is sectional drawing which shows the example which incorporated the light-emitting device concerning Embodiment 4 in the backlight. It is an enlarged view of the mounting part of the light-emitting device in the said backlight.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Embodiment 1]
1 to 3 show a schematic configuration of the light emitting device 100 according to the first embodiment.

  FIG. 3 is a side view of the light emitting device 100, and as can be seen from this figure, white LEDs 11 and infrared LEDs 12 are alternately arranged on the substrate 1. In addition, external connection terminals 2 to 5 are formed on one end side in the longitudinal direction of the substrate 1 (left end side in the figure). Here, the external connection terminal 2 is a white LED anode, the external connection terminal 3 is an infrared LED anode, the external connection terminal 4 is a white LED cathode, and the external connection terminal 5 is an infrared LED cathode.

  FIG. 1 is a top view of the light emitting device 100, and shows a state in which external connection terminals 2 and 3, white LEDs 11, and infrared LEDs 12 are formed on the top surface of the substrate 1. As described above, the white LEDs 11 and the infrared LEDs 12 are alternately formed along the longitudinal direction of the substrate 1, and the LEDs at both ends thereof are the infrared LEDs 12.

  FIG. 2 is a bottom view of the light emitting device 100 and shows a state in which the external connection terminals 4 and 5 are formed on the bottom surface of the substrate 1.

  FIG. 6 is a side cross-sectional view of the substrate 1, and the wiring of the two types of LEDs, that is, the white LED 11 and the infrared LED 12, is well separated by using a three-layer multilayer substrate.

<Details of substrate manufacturing process>
FIGS. 1 to 3 show a linear light source using an elongated substrate 1, which is formed by using a planar substrate and is divided into individual linear light sources. It is done.

  Here, the substrate manufacturing process will be described below, with the substrate used as a linear light source after the division being represented as the substrate 1 and the substrate before the division being the substrate 150.

FIG. 6 is a cross-sectional view showing an outline of the wiring inner layer pattern of the substrate 150, and FIG. 7 is a top view showing details of the chip arrangement. FIG. 7 shows the chip arrangement in an area corresponding to the divided substrate 1. Here, the substrate 150 is
Material: BT resin (bismaleimide / triazine resin),
Thickness: 0.58mm,
Size: 83mm x 75mm
Suppose that

  As shown in FIG. 6, the substrate 150 has a four-layer wiring pattern by overlapping an upper layer base material, a core base material, and a lower layer base material. In the following description, the uppermost surface is the first layer (wiring pattern). 9 and 10 (see FIG. 7)), and the second layer (wiring pattern 15a), the third layer (wiring pattern 14a), and the fourth layer (wiring pattern 13a) are moved to the lower layer. The first-layer wiring pattern 10 and the fourth-layer wiring pattern 13 a are connected through a through hole 13. The first-layer wiring pattern 9 and the third-layer wiring pattern 14 a are connected through a through hole 14. The first-layer wiring pattern 9 and the second-layer wiring pattern 15 a are connected through a through hole 15. Further, a white LED 11 and an infrared LED 12 are further formed on the upper surface of the substrate 150.

  Here, the thickness of each layer is 0.066 mm for the first layer wiring pattern, 0.018 mm for the second layer wiring pattern, 0.018 mm for the third layer wiring pattern, and the fourth wiring pattern 13 a. It is assumed that it is 0.037 mm. The base material thickness between the wiring patterns is such that the thickness of the lower layer base material 20 between the third and fourth layer patterns is 0.060 mm, and the thickness of the core base material 21 between the second and third layer patterns. Is 0.300 mm, and the thickness of the upper layer base material 22 between the first and second layer patterns is 0.060 mm. further. The resist thickness for wiring protection on the lower surface of the substrate is set to 0.021 mm. As described above, the total thickness of the four-layer substrate 150 is 0.58 mm.

  In the manufacturing process of the substrate 150, first, the wiring patterns 15a and 14a of the second layer and the third layer are formed on the core material (the core base material 21 on which the copper foil is formed on both sides), and resists are formed and etched. Use to form.

  And the lower layer base material 20, the upper layer base material 22, and copper foil which consist of PP (polypropylene) are affixed on the said core material in which the wiring pattern of the 2nd layer and the 3rd layer was formed, and with respect to this copper foil First-layer and second-layer wiring patterns 9, 10, 13a are formed using resist formation and etching.

  Thereafter, through-hole drilling (φ: 120 μm), laser processing, and copper plating are performed. At this time, plating is made on the wall surface of the through hole to obtain an electrical connection.

Next, white LEDs 11 and infrared LEDs 12 are alternately mounted at equal intervals on the first-layer wiring pattern (if the arrangement interval is changed for each LED in a backlight using one light guide plate described later) There is a problem that light distribution occurs and dark areas are likely to occur near the frame if they are not evenly spaced). The wiring pattern of the first layer includes a first wiring pattern 10 for mounting the infrared LED 12 and a second wiring pattern 9 for mounting the white LED 11.

  The first wiring pattern 10 for the infrared LED 12 becomes a wiring pattern that bypasses the second wiring pattern 9 for the white LED 11, is connected to the fourth-layer wiring pattern 13a through the through hole 13, and is further connected to the external connection terminal. 5 is connected. Further, the first wiring pattern 10 is connected to the external connection terminal 3 in the first layer.

  The white LED 11 is connected to the third-layer wiring pattern 14a through the through-hole 14, and further connected to the fourth-layer external connection terminal 4 through the through-hole 14b.

  The external connection terminal 2 is connected to the second-layer wiring pattern 15a through the through hole 15b.

  The second wiring pattern 9 for the white LED 11 is located in the first wiring pattern 10 for the detoured infrared LED, and is connected to the second-layer wiring pattern 15a through the through hole 15. Are electrically connected.

<Production of Light-Emitting Device 100>
Then, the manufacturing process of the light-emitting device 100 is shown.

  As shown in FIG. 4A, the first wiring pattern 9 and the second wiring pattern 10 (Cu: 0.015 mm, electrolytic Cu plating: 0.027 mm, electrolytic Ni plating: 0.015 mm + electrolytic Ag plating are formed on the substrate 150. : 0.009 mm). FIG. 4B shows an enlarged view of the wiring pattern and shows the wiring pattern in detail.

  FIG. 4B shows the first wiring pattern 10 for mounting the infrared LED 12, the second wiring pattern 9 for mounting the white LED 11, the through hole 13, the through hole 15, the external connection terminal 2, and the outside. A mode that the connection terminal 3 is formed is shown.

  As shown in FIG. 4A, at a predetermined location on the first wiring pattern 10, 0.32 mm × 0.32 mm × height of the infrared LED 12 emitting infrared light having a peak wavelength of 850 nm as the infrared LED 12. 40 18 mm AlGaAs infrared LEDs were arranged in the Y direction and 280 on the substrate 150 (fixed with Ag paste).

  Next, an InGaN-based LED of 0.24 mm × 0.40 mm × 0.08 mm in height that emits blue light with a peak wavelength of 450 nm is arranged in the Y direction as a white LED 11 at a predetermined location on the second wiring pattern 9. Forty pieces and 240 pieces were arranged on the substrate 150 (fixed with silicone resin).

  Here, in the die bonding step, first, the silicone resin is temporarily cured at a curing temperature of 100 ° C. for 1 hour. Thereafter, an epoxy-based Ag paste (curing temperature: 2 hours at 150 ° C.) and main curing of the silicone resin are performed at 150 ° C. for 2 hours.

  In order to prevent curing inhibition (die bond failure of white LED chip, occurrence of chip peeling failure, etc.), InGaN-based LED as white LED 11 and AlGaAs-based infrared LED as infrared LED 12 were die-bonded first.

  Next, wire bonding 40 of the white LED 11 and the infrared LED 12 is performed.

As shown in FIG. 5, the white LED 1 is formed on the second wiring pattern 9 formed on the substrate 150.
1. An infrared LED 12 is disposed on the first wiring pattern 10.

  FIG. 7 shows an enlarged view of the wiring pattern, and shows the wiring pattern, LEDs, and wires in detail. As shown in FIG. 7, a first wiring pattern 10 for mounting the infrared LED 12, a second wiring pattern 9 for mounting the white LED 11, a through hole 13, and a through hole 15 are formed.

<First resin application>
Next, as shown in FIG. 8, the first resin (phosphor-containing resin) is applied using a resin discharge device (not shown) so as to cover the white LED 11 mounted on the second wiring pattern 9. Form. Specifically, (Sr, Ba) ₂ SiO ₄ : Eu as a yellow phosphor and a filler for increasing the viscosity of a silicone resin under the conditions of a nozzle inner diameter of 0.05 mm and a resin discharge nozzle moving speed of 2.5 mm / sec. Silica) is mixed, and a silicone resin having a viscosity at 25 ° C. of 0.35 Pa · s is linearly drawn in the Y-axis direction of FIG. This operation is repeated 6 times per substrate. Then, it hardens for 10 minutes at the temperature of 100 degreeC, and implements temporary hardening.

  Here, in the present embodiment, in the first resin coating step, in order to disperse the phosphor uniformly in the coating resin, and in order to reduce the sedimentation of the phosphor in the coating resin over time after coating, It is preferable to perform thermosetting for 10 minutes at 100 ° C. every 10 substrates 150 (1 lot: 50 substrates). Thereby, the chromaticity change by fluorescent substance sedimentation in application | coating resin can be minimized.

Here, what is described as the white LED 11 in the present embodiment strictly includes one that generates white light by the action of a resin that covers the LED. That is, if a blue LED, which is a light emitting element that emits blue light as primary light, is coated with a resin containing a yellow phosphor as described above, the blue light emitted from the LED and the blue LED light as primary light are absorbed. Yellow light emitted from the yellow phosphor as secondary light is mixed, and as a result, white light is emitted from the resin covering the LED. The InGaN-based LED cited as a specific example of the white LED 11 described above is such a blue LED. It is also possible to use two types of phosphors, a green phosphor and a red phosphor, instead of a yellow phosphor, and mix white light with green light as the secondary light to obtain blue light as the primary light. In the present embodiment, such a configuration is also described as the white LED 11. Of course, a white LED that emits white light may be covered with a transparent resin to form the white LED 11. In addition to the above-described phosphor, β sialon as the green phosphor, and CASN (CaAlSiN ₃ : Eu ²⁺ ) or SCASN ((Sr _x Ca _1−x ) AlSiN ₃ : Eu ²⁺ ) as the red phosphor are preferably used. be able to.

<Second resin application>
Next, as shown in FIG. 10, a second resin (translucent resin) is used by using a resin discharge device (not shown) so as to cover the infrared LED 12 mounted on the first wiring pattern 10. Form. Specifically, a filler (silica) for increasing the viscosity of the silicone resin is mixed under the conditions of a nozzle inner diameter of 0.05 mm and a resin discharge nozzle moving speed of 2.5 mm / sec, and the viscosity at 25 ° C. is 0.35 Pa · s. The silicone resin is drawn in a straight line toward the Y-axis direction of FIG. This operation is repeated 7 times per substrate. Thereafter, it is thermally cured at a temperature of 150 ° C. for 5 hours.

  Here, the first resin body (phosphor-containing resin) 6 was formed with a width of 6 mm and a height of 0.35 mm, and the second resin body (translucent resin) 7 was formed with a width of 7 mm and a height of 0.38 mm. .

In heat curing for 5 hours at 150 ° C. after the second resin application, one lot (50 sheets) is cured together.

<Details of first and second resin shape manufacturing steps>
FIG. 9 shows a detailed side view of the light emitting device.

  The silicone resin that covers the white LED 11 and the infrared LED 12 is applied in a fixed amount. The silicone resin immediately after coating reaches a state about half of the white high reflectance photoresist 25 (width: 0.3 mm, height: 0.015 mm) provided on the left and right sides of the pattern.

  Since the viscosity of the silicone resin decreases during thermosetting, the silicone resin shows a behavior that spreads to the left and right. However, the silicone resin that has reached the end of the white high reflectance photoresist 25 does not flow out to the outside as it is, and the dome shape 65 of the white LED 11 The dome shape 75 of the infrared LED 12 can be manufactured.

  Here, the white high reflectance photoresist 25 has a flow preventing function of a dome shape 65 made of a first resin body (phosphor-containing resin) and a dome shape 75 made of a second resin body (transparent resin). Therefore, it is possible to keep the resin height constant by applying a fixed amount of resin and keeping the resin width constant, and the light emitting device with excellent chromaticity / luminosity accuracy by stabilizing the resin shape Is obtained.

  The dome shape that is a resin shape may be a trapezoidal shape or the like, and a concave portion such as a V-shape may be provided immediately above the LED.

<Division of light emitting device>
Thereafter, the thickness of the substrate 150 is 0.1 mm along the dicing line 30 provided on the left and right (pitch: 1.3 mm, width: 0.2 mm) and above and below (pitch: 57.37 mm, width: 0.2 mm). The light-emitting device 100 shown in FIG. 1 is obtained by dividing using a blade.

  Here, in order to reduce the occurrence of burrs, the wiring pattern is made such that the pattern is not cut as much as possible. As shown in FIG. 1, the metal portion to be divided divides (cuts) only the external connection terminals 2 and 3 and the external connection terminals 4 and 5 as shown in FIG. 2. Other divisions (cuts) are made by cutting only the base material, and the substrate design is performed so that the burr occurrence location is only the external connection terminal portion. For this reason, defects of the light emitting device due to burrs or the like generated during the division are reduced.

  As shown in FIGS. 2 and 7, external connection terminals 2 to 5 are provided at one end of the light-emitting device, and the electrode width (made of metal) of the wiring pattern is 0.2 mm (0. 1 mm) on the inner side (FIG. 7, B in FIG. 2). Therefore, a light-emitting device with less warpage and less burr generation can be manufactured with high productivity.

  The reason why only the area of the external connection terminals 2 to 5 is made the same as the width of the light emitting device is that the wettability of the solder of the reflow solder and the solder placement are good. That is, since the end of the external connection terminal is in contact with the long side of the light emitting device, when the light emitting device is held upright, the reflow solder of the holding portion melts and rises to the external connection terminal. .

<Comparison of infrared LED and white LED arrangement>
FIG. 11 shows a schematic diagram of a touch panel combined display device in which the light emitting device 100 is disposed on the end face of the light guide plate 110 and light is incident on the light guide plate to serve as a backlight light source of the liquid crystal 120 (detailed structure such as an optical sensor and a prism sheet). Is omitted).

For comparison with the present invention, a light-emitting device was manufactured with six infrared LEDs 12 and six white LEDs 11, and it was found that the distribution of infrared light from the light-emitting device was not uniform. In order to make the distribution of infrared light uniform, infrared LEDs 12 are arranged at both ends.

  Therefore, in order for infrared light to be uniform in the backlight, it is preferable to increase the number of infrared LEDs by one more than the number of white LEDs and to dispose infrared LEDs at both ends.

  Since the chip height (180 μm) of the infrared LED 12 is higher than the chip height (80 μm) of the white LED 11, the length of the second resin body 65 including the infrared LED 12 is 7 mm, and the first resin body including the white LED 11 The length of 75 was 6 mm, and the distance between the first resin body 65 and the second resin body 75 was 1.32 mm. Thereby, infrared light and white light are uniformly distributed in the backlight.

  Here, as an example of a lighting method, for example, a DC driving method and a pulse driving method in which the infrared LED 12 is 50 mA and the white LED 11 is 20 mA can be used.

  Here, the white LED 11 of the present embodiment uses a two-wire chip, but it goes without saying that it may be a one-wire.

[Embodiment 2]
In the light-emitting device 100 of the said Embodiment 1, the multilayer substrate structure which has a 3-layer base material and a 4-layer wiring pattern is illustrated. In the second embodiment, a configuration example of a light-emitting device 200 using a single-layer double-sided substrate will be described with reference to FIGS. 12A is a top view of the light emitting device 200, FIG. 12B is a bottom view of the light emitting device 200, and FIG. 12C is a cross-sectional view of the light emitting device 200.

  The light emitting device 200 includes a plurality of white LEDs 203 and infrared LEDs 202 arranged linearly on a substrate, and the white LEDs 203 and the infrared LEDs 202 are alternately arranged.

  The infrared LEDs 202 are connected in series by a plurality of infrared LED patterns provided on the substrate surface. One of the two infrared LED patterns on both sides has an external connection terminal 201 and the other has an external connection terminal 205. That is, the plurality of infrared LEDs 202 are connected in series between the external connection terminals 201 and 205 disposed at both ends of the substrate surface.

  The white LED 203 is connected in series by a plurality of white LED patterns provided on the back surface of the substrate and a plurality of white LED patterns provided on the substrate surface. Of the two white LED patterns provided on the back surface of the substrate, one of the two sides has an external connection terminal 206 and the other has an external connection terminal 207. The white LED pattern provided on the back surface of the substrate and the white LED pattern provided on the substrate surface are connected in series via the through hole 204. That is, the plurality of white LEDs 203 are connected in series between the external connection terminals 206 and 207 disposed at both ends of the back surface of the substrate.

  According to the above structure, an inexpensive light emitting device can be provided without using a multilayer substrate. Further, by providing the external connection terminals on both sides, the heat dissipation path can be made on the left and right sides of the substrate, so that the heat dissipation efficiency is also improved.

[Embodiment 3]
As described above, the light-emitting device of the present invention is formed by using a planar substrate and is obtained by dividing the light-emitting device into individual linear light sources. In the first embodiment, it is described that the wiring pattern is not cut as much as possible in order to reduce the occurrence of burrs. That is, in the first embodiment, the metal portion to be divided is divided (cut) only from the external connection terminals 2 and 3 shown in FIG. 1 and the external connection terminals 4 and 5 shown in FIG.

  However, even in the above example, burrs are generated in the pattern division portion of the external connection terminal, and this burr becomes an obstacle in soldering the connection terminal to the mounting board. For this reason, in this Embodiment 3, the structure for further suppressing also the burr | flash of an external connection terminal part is demonstrated. The following description exemplifies the formation portions of the external connection terminals 2 and 3, but the same applies to the formation portions of the external connection terminals 4 and 5 and the external connection terminals 201 and 205 to 207 (see FIG. 12). it can.

  FIG. 13A shows a part of the planar substrate on which the light emitting device before division in the first embodiment is formed, and FIG. 13B shows the vicinity of the external connection terminals 2 and 3 ( It is an enlarged view of the dashed-dotted line frame surrounding part of Fig.13 (a). And when it divides | segments along the dicing line in FIG.13 (b), the external connection terminals 2 and 3 of the light-emitting device obtained will become as shown in FIG.13 (c).

  As shown in FIG. 13C, the external connection terminals 2 and 3 in the first embodiment have only the area of the external connection terminal portion the same as the width of the light emitting device, and solder wettability and scooping up during reflow soldering. It is designed to improve.

  On the other hand, when mounting the light emitting device 100 which is a linear light source on the mounting substrate (flexible substrate or the like) 160, as shown in FIG. 14, the cut surface by dicing is brought into contact with the substrate surface of the mounting substrate 160, thereby the light emitting device. The external connection terminals 2 to 5 and the terminals of the mounting board are connected by reflow solder 35. At this time, if a burr is generated at the edge of the external connection terminal applied to the dicing line, it may be an obstacle to soldering in the mounting.

  In the third embodiment, in order to suppress burrs at the edges of the external connection terminals 2 and 3, the shape of the external connection terminals 2 and 3 formed on the planar substrate before cutting is shown in FIG. The shape is as shown in 16 (a). That is, the line width on the dicing line 30 is narrowed at one or both edges of the dicing line 30 to minimize the occurrence of burrs. When the external connection terminals 2 before wafer division are formed by electroplating, it is preferable that the external connection terminals 2 be formed without being separated. Therefore, in the external connection terminals 2, the external connection terminal portions are left slightly on the dicing lines. Yes. Thus, the shapes of the external connection terminals 2 and 3 after cutting are as shown in FIG. 15B or FIG.

  In the shape of the external connection terminals 2 and 3 shown in FIG. 15B or FIG. 16B, since the reflow solder portion is the same as the end face of the light emitting device, the reflow solder can be used without any problem and burrs can be reduced. Note that, as shown in FIG. 16 (b), the configuration in which burrs are reduced at both edges is effective in the case of manual soldering.

[Embodiment 4]
The characteristics of the light emitting device are degraded due to self-heating during operation, and thus it is necessary to sufficiently consider the heat dissipation. In particular, in a light-emitting device including a plurality of white LEDs and infrared LEDs arranged linearly on a substrate according to each of the above embodiments, the LED mounted on the light-emitting device can be compared to a configuration using a single light source. Since power consumption increases by the number, it is necessary to take measures especially for heat dissipation.

In the fourth embodiment, the following configuration is proposed as a heat dissipation measure.
In the light emitting device, as shown in FIGS. 17 and 18, the heat radiation post 50 is arranged on the pattern portion where the white LED 203 and the infrared LED 202 are mounted, and the heat generated during the operation of the white LED 203 and the infrared LED 202 is dissipated. It is led to the back surface of the substrate through the post 50. still,
17 and 18 show an example in which the configuration of the fourth embodiment is adopted in the light-emitting device using the single-sided double-sided substrate in the second embodiment.

Since the heat radiation post 50 is mainly composed of a metal material such as Cu and has conductivity, the surface thereof is covered with an insulating coating. The heat radiation post 50 corresponding to the infrared LED 20 is provided with a clearance so as not to contact the wiring pattern on the back side (A), but electrically connected to the wiring pattern on the back side like the heat radiation post 50 corresponding to the white LED 203. (B). The through hole 204 and the heat radiation post 50 can be made of the same material, and therefore can be formed in the same process.
-A further heat dissipation effect can be expected by changing the substrate material from BT resin to an inorganic material (alumina + tungsten), an aluminum substrate, or the like that has an excellent heat dissipation effect.

  FIG. 19 shows a schematic configuration of a backlight using the light emitting device, and FIG. The backlight in this case includes a light guide plate 411, an LED, a prism sheet (not shown), a housing 414 for fixing these, and a fixing bezel 412 when the device is incorporated. When the backlight is incorporated with the above configuration, the heat radiation sheet 413 or the like having a high thermal conductivity is adhered to ensure that the back surface of the LED substrate and the bezel 412 are securely adhered.

  Thus, efficient heat radiation becomes possible by forming a heat radiation path with the heat radiation post 50, the heat radiation sheet 413, and the bezel 412 against the heat generated from the white LED and the infrared LED.

<Application example>
The light emitting device of the present invention is used for a display of a digital camera or a digital single-lens reflex camera, and a display screen is used as a touch panel method, so that it is compared with a configuration in which a resistive film method or a capacitance method is externally attached on a liquid crystal. It is possible to input and change shooting conditions and the like while displaying a shooting screen by liquid crystal display with good image quality without using an external member. For example, the shutter speed, aperture, sensitivity, shooting mode, and the like can be displayed and can be changed by touching them.

  In addition, the light emitting device of the present invention can be used in a CCD camera portion of an on-vehicle back monitor that takes a picture when the vehicle is moving backward and notifies the driver of the situation behind the vehicle.

  The conventional back monitor for in-vehicle use obtains an image with the light of the backward light at night, but a light source that emits a wavelength in the invisible light region (infrared light emitting LED lamp) is added, and the wavelength in the invisible light region is added to the CCD camera. A light receiving element with high sensitivity is used to ensure night vision.

  From the background that LEDs are used as in-vehicle light sources, it is natural that the light source of the back monitor is also converted to LEDs. The device integrating the white light source LED and the infrared light source LED can be converted into a back monitor light source LED and can be miniaturized.

  Moreover, it can use suitably for the portable game machine and portable apparatus provided with the touchscreen liquid crystal screen. By using the light emitting device of the present invention, a game screen by a liquid crystal display can be displayed with a better image quality without using an external member, compared to a configuration in which a resistive film method or a capacitance method is externally attached on a liquid crystal. Meanwhile, it is possible to input and change various conditions in the game. The above conditions include: how to play, setting of player equipment (items used during the game), decision making during the game (escape, fight, etc.), selection of use of devices (items) These can be selected by touching the screen.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

1 Substrate 2-5, 201, 205-207 External connection terminal 11, 203 White LED
12,202 Infrared LED
100,200 light emitting device

Claims (17)

A substrate,
A plurality of white LEDs and a plurality of infrared LEDs arranged linearly on the substrate,
The white LED and the infrared LED are alternately arranged ,
The infrared LED is disposed at both ends of the substrate . The light emitting device according to claim 1, wherein the white LED includes a light emitting element that emits primary light and a phosphor that absorbs the primary light and emits secondary light. The light emitting device according to claim 1 or 2 , wherein the infrared LEDs are electrically connected in series, and the white LEDs are also electrically connected in series. The light emitting device according to any one of claims 1 to 3, characterized in that the white LED and the external connection terminals for supplying electricity to the infrared LED is provided at an end portion of the substrate. The light emitting device according to claim 4 , wherein the external connection terminal is provided at one end of the substrate. The light emitting device according to the at least one end of the external connection terminal is formed to the long side of the light emitting device from claim 1, wherein either the 5. The light emitting device according to claim 6 , wherein the external connection terminal is thinned at a portion formed up to a long side of the light emitting device. The white LED is coated with a first resin body, the infrared LED is coated with a second resin body,
The light emitting device according to any one of 7 from claim 1, characterized in that the white high reflectance photoresist is formed on both ends of the first resin body and the second resin body. The substrate, claim 1, wherein the wiring pattern for electrically connecting the wiring pattern and infrared LED for electrically connecting the white LED on its upper and lower surfaces are formed 8 The light emitting device according to any one of the above. The light emitting device according to claim 9 , wherein a through hole for wiring is formed inside the substrate. The light emitting device according to any one of claims 1 to 10 , wherein the substrate is composed of a laminated substrate in which base materials made of bismaleimide / triazine resin are laminated. The substrate, upper substrate, the light emitting device according to any one of the core substrate, claim 1, characterized in that a multilayer board formed by laminating the lower substrate 11. On the surface on the upper layer substrate, claim 12, characterized in that the wiring pattern for the infrared LED and the white LED, the external connection terminals for the infrared LED and the white LED is formed The light emitting device according to 1. Through holes for wiring are formed inside the upper layer base material, core base material, and lower layer base material,
Wherein the surface side of the board wiring pattern for electrically connecting the white LED is formed, in claim 12, further with the through hole and the wiring pattern is characterized by being electrically connected The light-emitting device of description. The light emitting device according to claim 12 , wherein a wiring pattern for electrically connecting the infrared LED and an external connection terminal of the infrared LED is formed on a back surface side of the substrate. The light emitting device according to any one of claims 1 to 15 , wherein a heat radiating post penetrating the substrate is formed on a lower portion of the mounting portion of the white LED and the infrared LED on the substrate. A through hole for wiring is formed inside the substrate,
The light emitting device according to claim 16 , wherein the heat radiation post and the through hole are made of the same material.

Images