JP5506446B2 - Side edge type planar light emitting device - Google Patents

Description

  The present invention relates to a side-edge type planar light-emitting device in which a linear light-emitting device comprising a plurality of LED packages arranged and a plurality of LED chips arranged (referred to as an LED array) is combined with a light guide plate. The side edge type planar light emitting device is used as a backlight light source of a liquid crystal display (LCD) device.

  2. Description of the Related Art A planar light emitting device used as a backlight light source of an LCD device is mainly a device using an LED element instead of a cold cathode fluorescent lamp (CCFL). Thereby, thickness reduction, weight reduction, power saving, etc. are aimed at. Surface light-emitting devices using LED elements are broadly classified into side-edge type and direct type, but side-edge type surface light-emitting devices are particularly superior in terms of thinning compared to direct-type surface light-emitting devices. Yes.

  In a side-edge type planar light emitting device including a conventional linear LED array used in an LCD device, a light guide plate made of a transparent member such as acrylic resin or polycarbonate is disposed on the back surface of the LCD panel, and a line is formed on the side surface of the light guide plate. LED array is arranged. In this case, since the light guide plate and the LED array are not in contact, when the light guide plate expands and contracts due to heat, the distance between the light guide plate and the LED array also varies. Therefore, in order to secure the distance between the light guide plate and the LED array and to ensure the light capturing efficiency to the light guide plate, ring-shaped or cap-shaped spacers made of elastic members are provided on the outer periphery of both ends of the LED array. (Reference: Patent Document 1).

JP 2008-192523 A

  However, in the above-described conventional side edge type planar light emitting device, the linearly arranged LED array is elongated, so that the light guide plate and the LED array can be obtained by using only ring-shaped or cap-shaped spacers provided only at both ends of the LED array. There is a problem that it is not possible to secure the distance. In particular, when applied to a large LCD device, a linearly arranged LED array becomes very long and particularly prominent.

  Although it is possible to provide the above-mentioned ring-shaped spacer in the middle of the LED array to ensure the distance between the light guide plate and the LED array, the ring-shaped spacer is actually provided in the middle of the LED array. This is very difficult, and the spacer in the middle exists as a shadow with respect to the light from the LED array, resulting in a decrease in light emission efficiency.

In order to solve the above problems, the present invention provides a light guide plate made of a transparent member, the side-edge type planar light-emitting device comprising a LED array disposed provided linear on the side surface side of the light guide plate The LED array includes a mounting board, a plurality of LED chips arranged in a row in the center on the mounting board, and a plurality of cylindrical or rectangular parallelepiped spacers provided on the mounting board. The spacers are arranged in regions on both sides of the LED chip row that do not face the LED chips . Thereby, the distance between the light guide plate and the LED array is ensured, and the spacer does not interfere with the light from the LED chip .

Furthermore, the above-mentioned spacers are arranged in a staggered manner .

According to the present invention, the distance between the light guide plate and the LED array is reliably ensured, even if the light guide plate is varied by the heat, the distance of the light guide plate and the LED chip is secured, the light guide plate LED It will not touch the tip and cause no lighting or other problems.

It is sectional drawing which shows embodiment of the side edge type planar light-emitting device concerning this invention. It is a top view of the LED array of FIG. It is a flowchart for demonstrating the manufacturing method of the side edge type planar light-emitting device of FIG.

  FIG. 1 is a sectional view showing an embodiment of a side edge type planar light emitting device according to the present invention. In FIG. 1, a light guide plate 2 made of a transparent member such as acrylic resin or polycarbonate is disposed on the back surface of the LCD panel 1, and a linear LED array 3 is disposed on the side surface of the light guide plate 2. In this case, the LED array 3 is fixed to the LCD panel 1 by the bezel 4.

  A reflective sheet 2 a is provided on the back side of the light guide plate 2, and a diffusion plate 2 b is provided on the front side of the light guide plate 2. Further, a dot pattern 2 c is printed on the back surface of the light guide plate 2. The reflection sheet 2a is for reflecting light, the dot pattern 2c is for uniformly controlling the emission luminance from the light guide plate emission surface, and the diffusion plate 2b is for diffusing light. .

  The LED array 3 includes a mounting substrate 31 made of, for example, aluminum, copper, glass epoxy resin, or polyimide, an LED chip 32 mounted on the mounting substrate 31, and a spacer 33 provided on the mounting substrate 31.

  In FIG. 1, as indicated by an arrow, light is incident from the side surface of the light guide plate 2 from the LED chip 32 of the LED array 3, and the dots on the back surface of the light guide plate 2 are reflected while reflecting between the front and back surfaces in the light guide plate 2. The light is scattered by the pattern 2c, and the scattered light is emitted from the light exit surface on the front surface of the light guide plate 2 and is incident on the LCD panel 1 through the diffusion plate 2b.

  As shown in FIG. 2 which is a plan view of the LED array 3 in FIG. 1, the LED chips 32 are arranged in a row at the center of the mounting substrate 31 and are connected in series by Au bonding wires 34.

  As shown in FIG. 2, the spacers 33 are formed of a metal or resin having a cylindrical shape, and are arranged on both sides of the LED chip 32 in regions not facing the LED chip 32 and in a staggered manner. Therefore, the spacer 33 does not interfere with the light from the LED chip 32. The cylindrical shape of the spacer 33 may be another shape such as a rectangular parallelepiped shape.

  The energizing substrates 35 provided at both ends of the mounting substrate 31 in FIG. 2 are for supplying power to the LED chip 32.

  Next, a method for manufacturing the LED array 3 of FIG. 1 will be described with reference to the flowchart of FIG. The size of the LED array is about 2.5 mm × about 150 mm × height about 2 mm. Further, the thickness of the mounting substrate 31 is, for example, 0.3 mm to 1.0 mm, the LED chip 32 is about 0.3 mm × about 0.3 mm, the spacer 33 is a cylinder of about 0.2 mm in diameter × about 1 mm in height, or about 0.2 mm × about 0.2 mm. × It has a rectangular parallelepiped with a height of about 1mm.

  First, in step 301, a bonding agent such as a white silicone adhesive is applied on the mounting substrate 31.

  Next, in step 302, the LED chip 32, the spacer 33, and the energizing substrate 35 are mounted and the adhesive is cured. The spacer may be made of glass or resin, and a non-lighting tip that is taller than the tip may be used. The energizing substrate 35 is, for example, a glass epoxy substrate, a metal core substrate, or a ceramic substrate.

  Finally, in step 303, the LED chip 32 and the current-carrying substrate 35 are connected by the Au bonding wire 34.

  Thus, since the spacer 33 is mounted simultaneously with the LED chip 32, the side edge type planar light emitting device of FIG. 1 can be manufactured without increasing the number of special steps.

1: LCD panel 2: Light guide plate 2a: Reflective sheet 2b: Diffuser plate 2c: Dot pattern 21: Convex slope
22: concave slope
3: LED array 31: mounting substrate 32: LED chip 33: spacer 34: Au bonding wire 35: energizing substrate

Claims (2)

A light guide plate made of a transparent member;
In a side edge type planar light emitting device comprising: a linear LED array provided on a side surface of the light guide plate;
The LED array
A mounting board;
A plurality of LED chips arranged in a row in the center on the mounting substrate;
A plurality of cylindrical or rectangular parallelepiped spacers provided on the mounting substrate;
Comprising
The side-edge type planar light-emitting device, wherein the plurality of spacers are disposed on regions on both sides of the LED chip row and not facing the LED chips . The side edge type planar light emitting device according to claim 1 , wherein the spacers are arranged in a staggered pattern.

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