JP2006269078A - Led light source module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED light source module capable of effectively radiate heat generated by an LED chip to a secondary cooling system. <P>SOLUTION: In this LED light source module structure wherein a silicon submount mounting the LED chip is directly arranged on a base metal of a metal wiring substrate to realize a mounting structure with low thermal resistance, the LED chip, the silicon submount and the metal wiring substrate are arranged as prescribed for effectively diffusing the heat generated by the LED chip to a metal wiring substrate side to realize high heat dissipation effect. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a structure of an LED light source module using a plurality of LED chips.

Generally, a low output type LED chip is used as a backlight light source of a small liquid crystal display used in a mobile phone, a portable information terminal, or the like. On the other hand, a cold cathode tube capable of obtaining a high light output is used as a backlight light source for a large-sized liquid crystal display used in a television or a personal computer. However, in recent years, along with the practical application of high-power type LED chips capable of supplying about 1 W of power, the development of LED light source modules for liquid crystal backlights that can be used in large-sized liquid crystal displays using them has been carried out. It has been broken.
In general, an LED light source module used for a backlight light source uses an LED light source having a structure in which LED chips of three primary colors of red, blue, and green are arranged at equal intervals in a longitudinal direction on a long wiring board ( For example, Patent Document 1). White light obtained from such an LED light source is introduced into a light guide plate to cause surface emission, thereby functioning as a backlight for a liquid crystal display. Also, an LED light source module having a structure in which red, blue, and green LED chips are arranged as a set on a submount and the submount is arranged in parallel to the longitudinal direction of a long wiring board is used. (For example, Patent Document 2).

JP-A-6-178048 JP-A-8-116401

Usually, in order to apply an LED backlight to a large liquid crystal display, a high light output is required. Therefore, the input power to the LED chip increases and the amount of heat generated from the LED chip increases. In order to ensure the reliability of the LED chip, a light source module structure that effectively dissipates the generated heat is required.
Therefore, an object of the present invention is to provide a module structure capable of obtaining a high light output and effectively dissipating heat generated from the LED chip.

The heat generation density when a plurality of LED chips are arranged in series on the submount is higher because the LED chips are adjacent to each other in the longitudinal direction than in the short side direction of the arrangement. Therefore, in the present invention, in order to effectively dissipate heat from the LED chips, a silicon submount in which red, blue and green LED chips are mounted in a row is used, and the arrangement direction of the LED chips is the longitudinal direction of the metal wiring board. It is characterized in that heat is radiated in the longitudinal direction of the metal wiring board by making the arrangement orthogonal to the direction. Further, in order to effectively dissipate heat from the LED chip in the vertical direction of the metal wiring board, a silicon submount is directly mounted in a recess formed on the metal wiring board.

According to the present invention, it is possible to effectively dissipate the LED light source module, and an LED light source module capable of obtaining a high light output can be obtained.

In the present invention, as the material for the submount, silicon having high thermal conductivity, capable of forming fine wiring, and capable of reducing the cost by mass production is used. In addition, the wiring substrate used for arranging and electrically connecting a plurality of silicon submounts can be elongated to match the length of the short part of the large liquid crystal display. It is preferable to use a material having a high heat dissipation effect. Therefore, in the present invention, a metal having high mechanical strength and high thermal conductivity is used as the wiring board. Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a cross-sectional view of the LED light source module 4 of the present invention. It consists of a structure in which a plurality of silicon submounts 2 mounted with a plurality of LED chips 3 are arranged in the longitudinal direction of a long metal wiring board 1. Here, on each silicon submount 2, LED chips of three primary colors of red, blue, and green are mounted, and white light can be obtained by mixing these. FIG. 2 is a plan view of a silicon submount in which four LED chips 3 are mounted in a row on the silicon submount 2. The number of LED chips 3 for each color is set to one red, one blue, and two green to align the white balance, and green LED chips are arranged on both sides. The most efficient heat radiation effect can be obtained by arranging the green LED chips with the largest amount of heat generation on both sides. FIG. 3 shows a conventional example. In general, the submount in which the LED chips 3 are mounted in a row is arranged so that the arrangement direction of the LED chips 3 and the longitudinal direction of the metal wiring board 1 are parallel to reduce color unevenness. In the present invention, as shown in FIG. 4, the arrangement direction of the LED chips 3 on the silicon submount 2 is arranged so as to be orthogonal to the longitudinal direction of the metal wiring board 1. FIG. 5 shows an overall view of a backlight light source 16 using the LED light source module 4 of the present invention. The LED light source module 4 is disposed relative to the end portion of the light guide plate 14, and light emitted from the LED is guided to the light guide plate 14 through the lens 15 and irradiates the back surface of the liquid crystal panel. When the LED light source module is applied to a backlight light source as shown in FIG. 4, it is preferable that the length of the short side of the metal wiring board is short in order to reduce the thickness of the liquid crystal display.

  In the structure of the present invention shown in FIG. 4, since the long side of the silicon submount having a high heat generation density is arranged orthogonal to the longitudinal direction of the metal wiring board, the heat from the LED chip is generated by the metal wiring board. The heat is effectively dissipated in the longitudinal direction. Since the LED chips 3 are arranged in a row on the silicon submount, the heat generated from the LED chip 3 is higher than the short side of the silicon submount shown by AM in FIG. The longer side indicated by is higher. This is because it is affected by heat generated from adjacent LED chips, and this effect tends to be higher as the gap between the LED chips is narrower. Therefore, in the case of the conventional arrangement method shown in FIG. 3, it is necessary to sufficiently widen the gap between the long side of the silicon submount and the long side of the metal wiring board 1 in order to ensure heat dissipation. Become. On the other hand, in the case of the present invention shown in FIG. 4, the long side of the silicon submount that increases the heat generation density is arranged perpendicular to the longitudinal direction of the metal wiring board 1. The distance from the side in the longitudinal direction of the metal wiring board 1 is not required, and the heat generated from the LED chip is effectively diffused in the longitudinal direction of the metal wiring board 1.

The detailed structure of the present invention will be described with reference to FIG.
In the silicon submount 2, an insulating layer is formed on the surface of the silicon substrate 10, and a wiring layer 12 is formed thereon. The LED chip 4 is bonded onto the wiring layer 12 by any one of solder, conductive adhesive, and ultrasonic methods. The insulating film formed on the surface of the silicon submount 2 can be a silicon oxide film, a silicon nitride film, an aluminum nitride film, or the like. The silicon submount 2 is arranged along the longitudinal direction of the long metal wiring substrate 1. The metal wiring substrate 1 includes a base substrate 5 made of aluminum, and an insulating layer 6 and a wiring layer 7 formed on the upper surface thereof. Here, the region on the metal wiring substrate 1 on which the silicon submount 2 is mounted is formed as a recess 8 from which the insulating layer 6 is removed, so that the base substrate 5 and the silicon submount 2 are provided with the insulating layer 6 having a high thermal resistance. It is possible to reduce the thermal resistance by mounting directly without intervention. The connection between the silicon submount 2 and the metal wiring board 1 is performed using a resin with high heat dissipation, such as silver paste 9. Next, the LED light source module 4 is manufactured by electrically connecting the wiring layer 7 of the metal wiring board 1 and the wiring layer 12 of the silicon submount 2 by wire bonding 13.

Next, an embodiment in which the LED chips 3 are arranged in a grid pattern on the silicon submount 2 having a square shape will be described. FIG. 7 is a plan view of a silicon submount used in this embodiment. The length of one side of the square silicon submount 2 is C, and the length of one side of the LED chip is A5. The structure of the LED light source module 4 other than the shape of the silicon submount 2 and the arrangement of the LED chips 3 is the same as that of the first embodiment. As shown in FIG. 7, the LED chips 3 are arranged in a grid pattern on the silicon submount 2. FIG. 8 is a plan view of the LED light source module in which such a square silicon submount 2 is mounted on the metal wiring board 1, and FIG.

  In the case of the arrangement, efficient heat dissipation can be achieved by appropriately setting the length B of the metal wiring board 1 in the short direction, the thickness T of the metal wiring board 1, and the length C of one side of the silicon submount 2. Can be realized.

  By three-dimensional heat conduction analysis, the relationship between the length B of the metal wiring board 1 in the short direction, the thickness T of the metal wiring board 1, and the length C of one side of the silicon submount 2 was numerically analyzed. As analysis conditions, aluminum (thermal conductivity is 237 W / mK) for the metal wiring substrate, silicon (thermal conductivity is 149 W / mK) for the submount, and silicon oxide for the insulating layer of the silicon submount. A film (thermal conductivity is 1 W / mK), a wiring layer is copper (thermal conductivity is 401 W / mk), and an Ag paste (thermal conductivity is 4 W / m) for connection between the silicon submount and the metal wiring substrate. mK) was used for analysis.

The result is shown in FIG. FIG. 10 shows the result of analyzing the relationship between C · T / B and the temperature rise at the point X on the metal wiring board 1. From the viewpoint of miniaturization, it is better that C · T / B is smaller. Further, as shown in FIG. Therefore, the value of C · T / B is preferably 5 or less. By adopting such a structure, an LED light source module capable of effective heat dissipation can be realized.

Sectional drawing of the LED light source module which concerns on this invention Plan view of silicon submount with multiple LED chips arranged in a row Plan view of conventional LED light source module The top view of the LED light source module which concerns on this invention Overall view of a liquid crystal backlight light source equipped with the LED light source module of Example 1 Detailed sectional view of the LED light source module of Example 1 Plan view of silicon submount after mounting LED chip of Example 2 Plan view of a metal wiring board on which the silicon submount of Example 2 is mounted Sectional drawing of the metal wiring board carrying the silicon | silicone submount of the present Example 2. C · T / B and point X on the metal wiring board 1 when the length B of the metal wiring board 1 in the short direction, the thickness T of the metal wiring board 1 and the length C of one side of the silicon submount 2 are given. Showing the result of analyzing the relationship with temperature rise

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal wiring board 2 Si submount 3 LED chip 4 LED light source module 5 Base substrate 6 Insulating layer 7 Wiring layer 8 Recess 9 Adhesive 10 Si substrate 11 Insulating layer 12 Wiring layer 13 Wire bonding 14 Light guide plate 15 Lens 16 Backlight light source

Claims (5)

In the LED light source module in which a plurality of submounts in which a plurality of LED chips are arranged in a row are arranged on a long substrate,
The LED light source module, wherein the arrangement direction of the LED chips on the submount is orthogonal to the longitudinal direction of the metal wiring board. The LED light source module according to claim 1.
An LED light source module comprising a plurality of recesses in a direction perpendicular to the longitudinal direction on the substrate, and a silicon submount mounted in the recesses. The LED light source module according to claim 1.
An LED light source module, which is a silicon submount in which one LED for red, one LED for blue, and two LED chips for green are mounted in a row, and green LED chips are arranged on both sides. In an LED light source module in which a plurality of silicon submounts in which a plurality of LED chips are arranged in a grid are arranged on a long metal substrate,
When the length of the metal substrate in the short direction is B, the thickness of the metal substrate is T, and the length of the silicon submount in the short direction of the metal substrate is C
C. T / B is 5 or less, LED light source module characterized by the above-mentioned. The LED light source module according to claim 4.
An LED light source module comprising a plurality of recesses in a direction perpendicular to the longitudinal direction on the substrate, and a silicon submount mounted in the recesses.

Images