JP2932471B2 - Surface light source and method for bonding light source to light guide plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining an LED light source and a light guide plate, and more particularly to a method for joining a light source and a light guide plate used for a backlight.

[0002]

2. Description of the Related Art An LED lamp has attracted attention as a surface light source for a backlight of a thin display device such as a liquid crystal display which does not emit light by itself. A light source using an LED lamp is formed as a surface light source by introducing light from the LED lamp from an end face in a thickness direction of the light guide plate and totally reflecting the light in the surface direction. The thickness of the light guide plate is usually as thin as about 2 to 5 mm, and light is introduced into the light guide plate by embedding the LED lamp in the end face of the thin light guide plate or by closely attaching it via a support or the like.

FIG. 4 is a sectional view showing a state of a surface light source in which an LED lamp light source is joined to an end face of a light guide plate 11 by a conventional method. Support 1 on which LED lamp 12 is mounted
3 and the end face of the light guide plate 11 are joined to make the plane of the light guide plate 11 a surface light source. In addition, the support 13 may be provided with a concave portion for fitting the end surface of the light guide plate 11. The support 13 is used when the LED lamp 12 is fixed and the LED lamp 12 is brought into close contact with the end face of the light guide plate 11 to introduce light, and is joined to the end face of the light guide plate 11. Conventionally, in order to join the light source and the end face of the light guide plate 11, a method of butting and a method of filling and bonding using an adhesive have been generally used. FIG. 4 shows a state in which the light source and the light guide plate 11 are joined by a butting method. The end face of the light guide plate 11 is inserted into a concave portion provided in the support 13 on which the LED lamp 12 is mounted. Thus, the light source and the light guide plate 11 are joined. In the method by filling and bonding using an adhesive, the end face of the light guide plate 11 is inserted into a concave portion provided in the support 13 on which the LED lamp 12 is mounted, in the same manner as the method of butting in FIG. However, the concave portion of the support 13 and the end surface of the light guide plate 11 are joined via a transparent adhesive.

[0004]

As described above, the LED light source and the end face of the light guide plate are joined by a butting method or an adhesive method. However, in the method of abutting and fixing without using an adhesive or the like, when the joint surface between the light source and the light guide plate is not a smooth mirror surface, a gap is formed in the joint surface and an air layer is formed between the light source and the end surface of the light guide plate. And the efficiency of introducing light deteriorates. Further, in the method of joining the light source and the light guide plate via an adhesive, light introduction efficiency is high because, for example, an epoxy resin or the like is used as the adhesive. However, such an adhesive has a low viscosity and thus has poor workability, and must be held under the curing conditions until it is cured, and there is a problem that an adhesion error such as an outflow of the adhesive is likely to occur. Furthermore, the adhesive is difficult to adhere unless it is a smooth mirror surface, and air bubbles may be mixed during curing.

Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to provide a light source and a light guide plate which have a slight unevenness in their joint surfaces when they are joined. An object of the present invention is to provide a method for joining a light source and a light guide plate that can obtain sufficient light introduction efficiency.

[0006]

The surface light source of the present invention is a flat light source.
Is connected to the light guide plate that becomes the surface light source and the end surface of the light guide plate and supported
Multiple LED lamps on the body along the end face of the light guide plate
This is a surface light source having a light source mounted thereon. Especially light guide
The plate has a double-sided tape with a transparent elastic body along its edge.
Is provided and the light guide plate is
The end face is in contact with the tips of the LED lamps that constitute the light source.
It is a surface light source combined. Also, if the light guide plate is acrylic or
Is polycarbonate and double-sided tape is
Any of resin, silicone rubber, acrylic foam
Surface light source. Further, the connection between the light source of the present invention and the light guide plate is performed.
The method is to mount multiple LED lamps on the support
This is a method of joining the light source and the end face of the light guide plate. Special
The tip of the LED lamps mounted on the support
A transparent plate provided along the end surface of the light guide plate with the end surface of the light plate
Light source and light guide bonded via double-sided tape with elastic body
It is a joining method with a board.

[0007] Figure 1 (a) and 2 (a) is a diagram showing the onset bright, be joined with a light source LED lamp 2 is mounted on the support 3 and an end face 5 of the light guide plate 1 Thereby, the plane of the light guide plate 1 is a surface light source. The support 3 and the end face 5 of the light guide plate 1 are joined via a transparent elastic body 4.

[0008]

[0009] FIG. 1 (b) and 2 (b) also present invention
A concave portion 6 is formed in the support 3 ′ of the light source so as to fit with the end surface 5 of the light guide plate 1, and the end surface 5 and the concave portion 6 are interposed via the transparent elastic body 4. Are joined. As described above, it is possible to join without providing a concave portion on the support, but it is possible to shift the bonding position or the like, so that a concave portion is formed in the support, and the end surface of the light guide plate is fitted and joined. Is preferred.

The elastic body 4 is not particularly limited as long as it has elasticity.
A resin or rubber that transmits the light of the D lamp 2 is used, and preferably, any one of a silicone resin, a silicone rubber, an acrylic foam, and an elastic adhesive is used. As the adhesive having elasticity, for example, a double-sided tape in which an adhesive is applied to both surfaces of an elastic substrate, a transparent adhesive having elasticity even after bonding, or the like is used. As the light guide plate 1, for example, acrylic, polycarbonate, or the like can be used.

[0011]

According to the joining method of the present invention, as shown in FIGS. 1 and 2, an end face 5 of a light guide plate 1 and a support 3 or 3 'on which an LED lamp 2 is mounted are connected to a transparent elastic body 4. Join through. Therefore, there is no occurrence of an adhesion error such as an outflow of the adhesive, which has been a problem when bonding is performed via the adhesive, and there is no risk of bubbles being mixed.

Further, according to the conventional method of abutting or filling and bonding, when the joint surface of the light source and the light guide plate is not a smooth mirror surface but has irregularities, a gap is formed in the joint surface and an air layer is formed between the light source and the light guide plate. Although the light introduction efficiency has deteriorated, such a problem is eliminated in the present invention because the bonding is performed via the elastic body 4. This is because the elastic body 4 acts as a cushion to fill a gap formed between the light source and the light guide plate 1.

FIG. 3 is a sectional view showing a state in which the light source and the light guide plate are joined by the method of the present invention, similarly to FIG. The LED lamp 2 is mounted on a support 3 ′ to serve as a light source. At this time, the bonding surface A of the support 3 ′ and the LED lamp 2
If the LED lamp 2 is not mounted so that the tips of the LED lamps 2 are flush with each other, a step is formed between the joint surface A of the support 3 ′ and the tip of the LED lamp 2. That is, as shown in FIG. 3A, the tip of the LED lamp 2 protrudes from the bonding surface A of the support 3 ′, or as shown in FIG.
Even if a work error such as a depression occurs, the bonding method of the present invention allows the elastic body 4 to move between the bonding surface A of the support 3 ′ and the tip of the LED lamp 2 as described above. Since the formed steps are filled, the light introduction efficiency does not decrease.

By the way, when silicon resin, silicone rubber, acrylic foam, or the like is used as the elastic body, there is an advantage that the workability is good and the light introduction efficiency does not decrease as described above as compared with the conventional method. In order to join the light source and the light guide plate using the elastic body, it is necessary to apply a certain pressure at the time of joining and keep the light source and the light guide plate as they are. However, when the light source and the light guide plate are joined using an elastic adhesive, they have an adhesive property unlike silicon resin or acrylic foam, so that the state can be maintained only by momentarily applying pressure. Sex is further improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. However, the following examples show one example of the present invention, and do not limit the present invention to the following.

FIG. 1 is a perspective view for explaining a method of the present invention, and FIG. 2 is a cross-sectional view showing a joint state between a light source and a light guide plate according to an embodiment of the present invention. Is a light guide plate, 2 is an LED lamp, 3 and 3 'are supports, 4 is a transparent elastic body, 5 is an end face of the light guide plate 1, and 6 is a recess formed in the support 3' of the light source. .

[Embodiment 1] The size is 126 × 96 × 3t.
The light guide plate 1 in which a diffusion pattern is screen-printed on the back surface of the acrylic plate is manufactured. Subsequently, the emission wavelength 480n
m, high-brightness blue LED lamp 2 having an emission output of 2 mW
Are prepared and fixed to the support 3 of white polycarbonate at equal intervals to produce a bar light source.

Next, the end face 5 of the light guide plate 1 is
As shown in (a), the transparent elastic body 4 is bonded to the light source via the silicone resin. FIG. 2A shows the light guide plate 1 at this time.
FIG. 3 is a cross-sectional view showing a bonding state between the light source and the light source.

Example 2 A light guide plate 1 and a light source are manufactured in the same manner as in Example 1. Subsequently, the light source and the light guide plate 1 were sealed with a transparent double-sided tape (F-946 manufactured by 3M) having a thickness of 0.125 mmt.
9pc). This double-sided tape is used in place of the elastic body 4 such as the silicone resin used in Example 1, and is made of a transparent adhesive having elasticity even after bonding.

Example 3 A light guide plate 1 is manufactured in the same manner as in Example 1. Subsequently, the high-intensity blue LED lamp 2 is
A bar light source is manufactured by fixing the light source to a white polycarbonate support 3 'at regular intervals. At this time, a concave portion 6 that fits with the end face 5 of the light guide plate 1 is formed in the support 3 ′ made of white polycarbonate as shown in FIG.

Next, the end face 5 of the light guide plate 1 is attached to a transparent double-sided tape (#M # 948 manufactured by 3M) having a thickness of 0.120 mmt.
Through 3), the light source is fitted into the concave portion 6 of the light source. This double-sided tape is also used in place of the elastic body 4 such as silicone resin as in the second embodiment, and is made of a transparent adhesive having elasticity even after bonding. FIG. 2B is a cross-sectional view showing a state of joining the light guide plate 1 and the light source at this time.

Embodiment 4 A light guide plate and a light source are manufactured in the same manner as in Embodiment 3. Subsequently, the concave portion 6 of the light source is passed through a transparent 1 mmt double-sided tape (3M Y-4910J) in which an adhesive is applied to both sides of an acrylic foam as an elastic body.
And the end face 5 of the light guide plate.

For the surface light source in which the light source and the light guide plate are joined by the methods of the first to fourth embodiments of the present invention, and the surface light source joined by the butt method as a conventional example, the measured emission luminance and light introduction are respectively measured. Table 1 shows the efficiency. However, in Examples 1 to 4 and the conventional example, the material and size of the light guide plate used, the light emission output and the number of LED lamps, etc.
All the measurement conditions are the same, and only the joining method is different. As can be seen from this table, the emission luminance of the surface light source obtained by the conventional method was 116.9 nit, but the emission intensity of the surface light source obtained by the method of the present invention showed a maximum of 146.7 nit. . Further, regarding the light introduction efficiency, when the surface light source obtained by the conventional method was set to 100%, the surface light source obtained by the method of the present invention was improved up to 125.5%.

As described above, when the light guide plate 1 and the light source are joined using the method of the present invention, the light emission luminance and the light introduction efficiency can be improved as compared with the conventional joining by butting.

[0025]

[Table 1]

In this embodiment, a high-brightness blue LED lamp is used as the LED lamp 2, but there is no particular limitation. As the light source support, white polycarbonate was used, but other acrylic, liquid crystal polymer, PBC, A
Any material having good reflection efficiency such as BS may be used. Although screen printing was used as a method of diffusing light, any other method can be used as long as uniform surface light emission can be obtained, such as blasting and molding.

[0027]

As described above, according to the method of the present invention, since the light source and the light guide plate are joined through the transparent elastic body, the light source and the light guide plate can be connected to each other even if each joint surface has some irregularities. Since no air layer is formed between the two, the light introduction efficiency can be further improved as compared with the conventional matching method. In addition, in the conventional method of joining via an adhesive, an adhesion error such as run-out is likely to occur, but the method of the present invention has an advantage that almost no adhesion error occurs and workability is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a method of the present invention.

FIG. 2 is a sectional view showing a state where a light source is joined to a light guide plate by the method of the present invention.

FIG. 3 is a sectional view showing a state where a light source is joined to a light guide plate by the method of the present invention.

FIG. 4 is a cross-sectional view showing a state in which a light source is joined to a light guide plate by a conventional method.

[Explanation of symbols]

 1, 11,... Light guide plate 2, 12,... LED lamp 3, 3'13,... Support 4, transparent elastic body 5,.・ Recess

Claims (3)

(57) [Claims] 1. A light guide plate whose plane is a surface light source, and the light guide plate
A plurality of LED lamps on the support
With a light source mounted along the end face direction of the light guide plate
Surface light source, wherein the light guide plate is transparent along its end surface.
A double-sided tape with a clear elastic body is provided
An end face of the light guide plate and a light source are formed via the double-sided tape.
That the tip of multiple LED lamps
Area light source 2. The light guide plate is made of acrylic or polycarbonate.
The double-sided tape is made of silicone resin
Grease, silicone rubber, or acrylic foam
The surface light source according to claim 1, wherein: 3. A plurality of LED lamps are mounted on a support.
This method is to join the light source and the end face of the light guide plate.
The tip of the plurality of LED lamps mounted on the support
And the end face of the light guide plate.
Bonding via a double-sided tape with a clear elastic body
Characteristic method of joining light source and light guide plate.