JP2007220830A - LIGHT EMITTING MODULE AND DISPLAY DEVICE AND LIGHTING DEVICE USING THE SAME - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting module in which temperature difference occurring in a substrate can be reduced, and to provide a display and an illuminator employing it. <P>SOLUTION: The light emitting module (1) comprises a heat sink (10), a substrate (11) provided on the heat sink (10), and a plurality of light emitting elements (12) mounted on a part of the major surface (11A) of the substrate (11) wherein the substrate (11) consists of a first region (11a) located directly under the plurality of light emitting elements (12), and a second region (11b) surrounding the first region (11a), and thermal resistance between the major surface (11A) and the heat sink (10) in the first region (11a) is lower than that between the major surface (11A) and the heat sink (10) in the second region (11b). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting module including a plurality of light emitting elements, and a display device and an illumination device using the light emitting module.

  Conventionally, research has been conducted on an illumination light source using a light emitting element such as a light emitting diode (hereinafter referred to as “LED”). Among them, an illumination light source including an LED module in which a plurality of LEDs are mounted on a substrate has an excellent advantage that it has a longer life compared to conventional incandescent bulbs, etc. Hidden.

  However, since light emitting elements such as LEDs emit a large amount of heat during light emission, when used as an illumination light source, a heat sink (heat dissipating member) needs to be disposed on the back side of the substrate on which the light emitting elements are mounted (for example, Patent Document 1).

  FIG. 12 shows a perspective view of the illumination light source proposed in Patent Document 1. In FIG. As shown in FIG. 12, the illumination light source 100 includes three LED modules 101, 102, and 103, a module socket 104 into which these modules are loaded, and a heat sink 105 attached to the back surface of the module socket 104.

  In the LED modules 101, 102, and 103, a plurality of LEDs 110 are mounted on the substrates 101a, 102a, and 103a, respectively. Usually, the substrates 101a, 102a, and 103a have an area that is slightly larger than the area where the LEDs 110 are mounted. Thereby, the mounting of the LED 110 is facilitated, and the heat generated from the LED 110 can be quickly dissipated to the heat sink 105.

The heat sink 105 is provided with fins 105a. Thereby, the illumination light source 100 can radiate | emit efficiently the heat | fever emitted from LED module 101,102,103.
JP 2004-253364 A

  However, in the configuration of the illumination light source 100 described above, in each of the substrates 101a, 102a, and 103a, the amount of heat transfer from the LED 110 in the LED 110 mounting area is greater than that in the other areas. There may be distortion due to the temperature difference between the two. In particular, when ceramic such as alumina is used as a constituent material of the substrates 101a, 102a, and 103a, the temperature difference may be 120 ° C. or more, and cracks may occur in the substrates 101a, 102a, and 103a.

  The present invention solves the above-described conventional problems, and provides a light emitting module capable of reducing a temperature difference generated in a substrate, and a display device and an illumination device using the light emitting module.

The light emitting module of the present invention is a light emitting module including a heat sink, a substrate provided on the heat sink, and a plurality of light emitting elements mounted on a part of the main surface of the substrate,
The substrate includes a first region located directly below the plurality of light emitting elements, and a second region surrounding the first region,
The thermal resistance between the main surface and the heat sink in the first region is smaller than the thermal resistance between the main surface and the heat sink in the second region.

  Both the display device and the illumination device of the present invention use the light emitting module of the present invention as a light source.

  According to the light emitting module, the display device, and the lighting device of the present invention, the temperature difference between the temperature of the region located immediately below the light emitting element and the temperature of other regions is reduced in the substrate on which the light emitting element is mounted. be able to. Thereby, distortion in the substrate can be suppressed.

  The light emitting module of the present invention includes a heat sink, a substrate provided on the heat sink, and a plurality of light emitting elements mounted on a part of the main surface of the substrate.

  The heat sink is not particularly limited, but preferably has a thermal resistance of 4 ° C./W or less from the viewpoint of heat dissipation. For example, a heat sink made of a metal such as copper or aluminum can be used. The substrate is not particularly limited, and a ceramic substrate such as alumina or a composite substrate including an inorganic filler and a thermosetting resin can be used.

  Examples of the light emitting element include an ultraviolet LED that emits ultraviolet light from near ultraviolet having a wavelength of 410 nm or less, a blue LED that emits blue light having a wavelength of 450 to 490 nm, and a green LED that emits green light having a wavelength of 500 to 550 nm. Alternatively, a red LED that emits red light having a wavelength of 590 to 650 nm can be used. As the ultraviolet LED, the blue LED, or the green LED, for example, an LED using an InGaAlN-based material can be used. Further, as the red LED, for example, an LED using an AlInGaP-based material can be used.

When the light emitting module is used as a white light emitting module, a white LED in which an ultraviolet LED, a blue LED, and a phosphor are combined may be used. For example, a white LED obtained by dispersing a phosphor in silicone resin or the like to form a phosphor paste and forming a phosphor layer on the UV LED or blue LED using the phosphor paste is used. That's fine. Examples of the phosphor include phosphors emitting blue light such as aluminate BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , silicate Ba ₃ MgSi ₂ O ₈ : Eu ²⁺ , and garnet structure Y ₃ (Al , Ga) ₅ O ₁₂ : Ce ³⁺ , silicate-based (Ba, Sr) ₂ SiO ₄ : Eu ^{2+ and} other phosphors emitting green light, and sialon-based Ca—Al—Si—O—N: Eu ²⁺ , Phosphors emitting yellow light, such as silicate (Sr, Ca) ₂ SiO ₄ : Eu ²⁺ , garnet structure (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ , and nitridosilicate Sr ₂ Si ₅ N ₈ : Eu ²⁺ , nitridoaluminosilicate CaAlSiN ₃ : Eu ²⁺ , oxonitridoaluminosilicate Sr ₂ Si ₄ AlON ₇ : Eu ²⁺ , sulfide CaS: Eu ²⁺ A phosphor that emits light can be used.

  In the light emitting module of the present invention, the substrate includes a first region located immediately below the plurality of light emitting elements, and a second region surrounding the first region. Further, the thermal resistance between the main surface and the heat sink in the first region (hereinafter also referred to as “first thermal resistance”) is the heat between the main surface and the heat sink in the second region. It is smaller than the resistance (hereinafter also referred to as “second thermal resistance”). With the above configuration, the amount of heat released from the first region located directly below the light emitting element is larger than the amount of heat released from the second region surrounding the first region. The temperature difference between the temperatures of the two regions can be reduced. Thereby, distortion in the substrate can be suppressed.

  In the light emitting module of the present invention, a value obtained by dividing the area of the main surface in the first region by the area of the main surface in the second region is preferably 0.5 to 2. Within this range, the light emitting element can be easily mounted without hindering downsizing of the light emitting module, and heat generated from the light emitting element can be quickly dissipated to the heat sink.

  In the light emitting module of the present invention, the first thermal resistance is made higher than the second thermal resistance by configuring at least a part of the first region from a material having a higher thermal conductivity than the material constituting the second region. It may be small. In this case, the thermal conductivity of the material constituting at least a part of the first region may be about 1.3 to 15 times the thermal conductivity of the material constituting the second region. For example, a metal such as copper or aluminum can be used as a material constituting at least a part of the first region, and a ceramic such as alumina or aluminum nitride can be used as a material constituting the second region.

  In the light emitting module of the present invention, the thickness of the first region is larger than that of the second region, and the first substrate is provided on the heat sink so that only the first region is in contact with the heat sink. The thermal resistance may be smaller than the second thermal resistance. In this case, the thickness of the second region may be, for example, about 30 to 80% of the thickness of the first region.

  In the light emitting module of the present invention, the first thermal resistance may be made smaller than the second thermal resistance by providing a recess in a contact surface with the heat sink in the second region. In this case, the concave portion may be provided so that the contact area with the heat sink in the second region is, for example, about 20 to 70% of the contact area with the heat sink in the first region. In addition, the shape of the said recessed part is not specifically limited, For example, what is necessary is just a hollow and a groove | channel.

  In the light emitting module of the present invention, the first thermal resistance may be made smaller than the second thermal resistance by providing thermal vias in the thickness direction of the substrate in the first region. As a constituent material of the thermal via, for example, a heat conductive material containing a metal such as gold, silver, copper, nickel or the like can be used. In this case, the ratio of the thermal via in the first region may be about 50 to 100% by volume, for example.

  Both the display device and the illumination device of the present invention use the light emitting module of the present invention as a light source. Thereby, as mentioned above, since the distortion which arises in the board | substrate of a light emitting module can be suppressed, the display apparatus and illuminating device excellent in durability can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that in the drawings to be referred to, components having substantially the same function are denoted by the same reference numerals, and redundant description may be omitted.

(First embodiment)
First, a light emitting module according to a first embodiment of the present invention will be described with reference to FIGS. 1A and 1B. FIG. 1A is a perspective view of a light emitting module according to a first embodiment of the present invention. 1B is a cross-sectional view taken along line II of FIG. 1A.

  As shown in FIGS. 1A and 1B, the light emitting module 1 includes a heat sink 10, a substrate 11 provided on the heat sink 10, and a plurality of light emitting elements 12 mounted on the central portion of the main surface 11 </ b> A of the substrate 11. . Each light emitting element 12 is mounted on the substrate 11 via a wire 13. An external connection terminal 14 is provided at the end of the main surface 11 </ b> A of the substrate 11.

  As shown in FIG. 1B, the substrate 11 includes a first region 11a located immediately below the plurality of light emitting elements 12, and a second region 11b surrounding the first region 11a. And the material 111 which comprises a part of 1st area | region 11a has a larger thermal conductivity than the material 112 which comprises the 2nd area | region 11b. Thereby, the thermal resistance (first thermal resistance) between the main surface 11A and the heat sink 10 in the first region 11a is changed to the thermal resistance (second thermal resistance) between the main surface 11A and the heat sink 10 in the second region 11b. ) Smaller. Since the light emitting module 1 has the above-described configuration, the amount of heat released from the first region 11a located directly below the light emitting element 12 is larger than the amount of heat released from the second region 11b surrounding the first region 11a. The temperature difference between the temperature of the first region 11a and the temperature of the second region 11b can be reduced. Thereby, the distortion in the substrate 11 can be suppressed.

Next, a temperature profile of the substrate 11 when the light emitting module 1 is used will be described. As for the size of the light emitting module 1 used for the measurement of the temperature profile, the length L ₁ in the longitudinal direction of the substrate 11 (see FIG. 1A) is 28.5 mm, and the length L ₂ in the width direction of the substrate 11 (see FIG. 1A). The length L ₃ (see FIG. 1A) in the longitudinal direction of the first region 11a was 11 mm, and the length L ₄ in the width direction (see FIG. 1A) of the first region 11a was 8 mm. Further, the thickness T ₁ (see FIG. 1B) of the substrate 11 is 1 mm, the thickness T ₂ (see FIG. 1B) of the heat sink 10 is 40 mm, and the thickness T _{3 of the} material 111 constituting a part of the first region 11a (see FIG. 1B). ) Was 0.7 mm. The heat sink 10 has a thermal resistance of 2.3 ° C./W, copper is used as the material 111 constituting a part of the first region 11a, and alumina is used as the material 112 constituting the second region 11b. used. Further, as a comparative example, the same light emitting module 1 as described above was prepared except that the substrate 11 was composed only of alumina.

  In FIG. 2, the surface temperature profile (solid line) of the board | substrate of the light emitting module 1 (Example) and the surface temperature profile (dashed line) of the board | substrate of a comparative example are shown. The measurement was carried out using an infrared thermography (TVS-8500 manufactured by Nippon Avionics Co., Ltd.) after being left for 60 minutes in a state where a current of 350 mA was passed through each light emitting element 12. The measurement location was the substrate surface on the XY broken line shown in FIG. 1A. 2 represents the distance from the point X in FIG. 1A. As shown in FIG. 2, in the comparative example, a temperature difference of about 120 ° C. occurred on the substrate surface. However, according to the example, the temperature difference of the substrate surface could be suppressed to about 70 ° C.

  The light emitting module 1 according to the first embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, as illustrated in FIG. 3, the first region 11 a may be a light emitting module configured only from the material 111.

(Second Embodiment)
Next, a light emitting module according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view of a light emitting module according to the second embodiment of the present invention.

  As shown in FIG. 4, in the light emitting module 2, the substrate 11 is made of the same material (for example, a ceramic material such as alumina), and the shape of the substrate 11 is the light emitting module 1 described above (see FIGS. 1A and 1B). ) Is different. In the substrate 11 of the light emitting module 2, the thickness of the first region 11 a is thicker than that of the second region 11 b, and only the first region 11 a is in contact with the heat sink 10. Also with this configuration, since the first thermal resistance can be made smaller than the second thermal resistance, the same effect as that of the light emitting module 1 described above can be exhibited.

  The light emitting module 2 according to the second embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, as illustrated in FIG. 5, a light emitting module in which a portion existing in the second region 11 b of the back surface 11 </ b> B opposite to the main surface 11 </ b> A of the substrate 11 is tapered may be used.

(Third embodiment)
Next, a light emitting module according to a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view of a light emitting module according to a third embodiment of the present invention.

  As shown in FIG. 6, in the light emitting module 3, the substrate 11 is made of the same material (for example, a ceramic material such as alumina), and the shape of the substrate 11 is the light emitting module 1 described above (see FIGS. 1A and 1B). ) Is different. In the substrate 11 of the light emitting module 3, a groove 11 c is provided in a portion of the back surface 11 </ b> B of the substrate 11 that exists in the second region 11 b. Also with this configuration, since the first thermal resistance can be made smaller than the second thermal resistance, the same effect as that of the light emitting module 1 described above can be exhibited.

  The light emitting module 3 according to the third embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, as shown in FIG. 7, it is good also as a light emitting module provided with the hollow 11d instead of the groove | channel 11c.

(Fourth embodiment)
Next, a light emitting module according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of a light emitting module according to a fourth embodiment of the present invention.

  As shown in FIG. 8, the light emitting module 4 further includes a substrate 11 made of the same material (for example, a ceramic material such as alumina) and a thermal via 40 provided through the first region 11a. It differs from the light emitting module 1 (refer FIG. 1A and B) mentioned above. Also with this configuration, since the first thermal resistance can be made smaller than the second thermal resistance, the same effect as that of the light emitting module 1 described above can be exhibited.

  The light emitting module 4 according to the fourth embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, as shown in FIG. 9, the thermal via 40 may be formed in a state of being embedded in the first region 11a without penetrating the first region 11a.

(Fifth embodiment)
Next, a display device (image display device) according to a fifth embodiment of the invention will be described with reference to the drawings. FIG. 10 to be referred to is a perspective view of an image display apparatus according to the fifth embodiment of the present invention.

  As shown in FIG. 10, the image display device 5 has a panel 50, and one main surface 50 a of the panel 50 is used as a light source in any one of the first to fourth embodiments described above. A plurality of such light emitting modules 51 are arranged in a matrix. Since the image display device 5 configured as described above uses the light emitting module 51 according to any one of the first to fourth embodiments described above as a light source, distortion generated in the substrate of the light emitting module 51 can be suppressed. it can. Thereby, the image display apparatus excellent in durability can be provided.

(Sixth embodiment)
Next, a lighting device (stand type lighting device) according to a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 11 to be referred to is a perspective view of a stand type illumination device according to the sixth embodiment of the present invention.

  As shown in FIG. 11, the stand-type illumination device 6 includes a trunk portion 60, a base portion 61 that is fixed to one end of the trunk portion 60 and supports the trunk portion 60, and an illumination portion 62 that is fixed to the other end of the trunk portion 60. Including. A plurality of light emitting modules 63 according to any one of the first to fourth embodiments described above are arranged in a matrix on one main surface 62a of the illumination unit 62 as a light source. Since the stand type lighting device 6 configured in this manner uses the light emitting module 63 according to any one of the first to fourth embodiments described above as a light source, distortion generated in the substrate of the light emitting module 63 is suppressed. Can do. Thereby, the stand type illuminating device excellent in durability can be provided.

  The present invention is useful for, for example, general illumination, effect illumination (sign lamp, etc.), backlight, illumination lamp, display, and the like.

A is a perspective view of the light emitting module according to the first embodiment of the present invention, and B is a cross-sectional view taken along line II of A. FIG. It is a graph which shows the surface temperature profile of the board | substrate in the light emitting module which concerns on 1st Embodiment of this invention, and the surface temperature profile of the board | substrate in the light emitting module of a comparative example. It is sectional drawing which shows the modification of the light emitting module which concerns on 1st Embodiment of this invention. It is sectional drawing of the light emitting module which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the modification of the light emitting module which concerns on 2nd Embodiment of this invention. It is sectional drawing of the light emitting module which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the modification of the light emitting module which concerns on 3rd Embodiment of this invention. It is sectional drawing of the light emitting module which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the modification of the light emitting module which concerns on 4th Embodiment of this invention. It is a perspective view of the image display apparatus which concerns on 5th Embodiment of this invention. It is a perspective view of the stand type illuminating device which concerns on 6th Embodiment of this invention. It is a perspective view of the conventional illumination light source.

Explanation of symbols

1, 2, 3, 4, 51, 63 Light emitting module 5 Image display device (display device)
6 Stand-type lighting device (lighting device)
DESCRIPTION OF SYMBOLS 10 Heat sink 11 Board | substrate 11A Main surface 11B Back surface 11a 1st area | region 11b 2nd area | region 11c Groove 11d Indentation 12 Light emitting element 13 Wire 14 External connection terminal 40 Thermal via 50 Panel 60 Body 61 Base 62 Illumination part 111 Part of 1st area | region A material constituting the second region 112

Claims (8)

A light emitting module including a heat sink, a substrate provided on the heat sink, and a plurality of light emitting elements mounted on a part of a main surface of the substrate;
The substrate includes a first region located directly below the plurality of light emitting elements, and a second region surrounding the first region,
The light emitting module according to claim 1, wherein a thermal resistance between the main surface and the heat sink in the first region is smaller than a thermal resistance between the main surface and the heat sink in the second region.   2. The light emitting module according to claim 1, wherein a value obtained by dividing an area of the main surface in the first region by an area of the main surface in the second region is 2 or less.   2. The light emitting module according to claim 1, wherein at least a part of the first region is made of a material having a higher thermal conductivity than a material forming the second region. The first region is thicker than the second region,
The light emitting module according to claim 1, wherein only the first region of the substrate is in contact with the heat sink.   The light emitting module according to claim 1, wherein a concave portion is provided on a contact surface with the heat sink in the second region.   The light emitting module according to claim 1, further comprising a thermal via provided in the thickness direction of the substrate in the first region.   The display apparatus which uses the light emitting module of any one of Claims 1-6 as a light source.   The illuminating device which uses the light emitting module of any one of Claims 1-6 as a light source.

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