JP2005038771A - Surface light source, display device and guiding light device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a surface light source device in which generated heat of an LED is efficiently radiated and which is bright without impairing the performance of the LED. <P>SOLUTION: The surface light source device is equipped with a plurality of LEDs being a light source, a LED substrate mounting the LEDs, a light guide plate which irradiates from the front emitting face the light of the light source entered from the incident surface on the side, and a display plate case housing the LEDs, the LED substrate, and the light guide plate. At least a part of the LED substrate is adhered to the inner surface of the display plate case, and the LEDs are arranged so as to be opposed to the incident surface on the side of the light guide plate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an edge light type surface light source device using a light guide plate and a display device that uses this surface light source device and is used for a guide light, an emergency light, a road sign, an advertisement light, and the like.

Conventional display devices such as guide light devices using a surface light source device using LEDs as light sources include the following.
Displayed by a light source in which a plurality of LEDs emitting blue light are arranged, a light guide plate that emits light from the light source incident from one side, a color conversion member that converts the light emission color of the light source into a different color, and illumination from the back Display by combining a display panel on which a display pattern such as symbols and characters is formed, and converting blue light into white light or light having other light spectrum components such as green, yellow, and red by a color conversion member. It is converted into white light or other different colors necessary for the display of the panel to display the display pattern.
The plurality of LEDs are mounted on the substrate at a constant pitch, and this substrate is detachably attached to the holder so as to be close to one side surface of the light guide plate, and light emitted to the side of the LED Reflecting plates for reflecting the light to the light guide plate are disposed on both sides of the substrate (see, for example, Patent Document 1).
JP-A-9-179512 (page 3, page 4, FIG. 1, FIG. 2)

In the case of using an LED as a light source, due to the characteristics of an LED, if a large amount of current is passed, a lot of heat is generated and the temperature becomes high. In the conventional display device, since the heat radiation of the LED is not sufficient, there is a problem that the characteristics of the LED itself are impaired, for example, the light output of the LED is reduced by generated heat.
For this reason, in order to maintain the characteristics of the LED itself, the current value must be lowered in order to suppress heat generation, and a sufficient amount of light as a display device cannot be obtained. Furthermore, if the number of LEDs is increased in order to obtain a light amount, there is a problem in that, in addition to an increase in the amount of heat generated by the LEDs, the cost also increases.

The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a bright surface light source device that efficiently dissipates heat generated by an LED and does not impair the performance of the LED.
It is another object of the present invention to obtain a display device such as a guide lamp device using the surface light source device.

  The surface light source device of the present invention includes a plurality of LEDs that are light sources, an LED substrate on which the LEDs are mounted, a light guide plate that irradiates light from a light source incident from an incident surface on a side surface as a surface light source from an irradiation surface on the front surface, A surface light source device including an LED, a LED board, and a display plate case that houses a light guide plate, wherein at least a part of the LED substrate is in close contact with the inner surface of the display plate case, and the LED is incident on a side surface of the light guide plate The LED substrate is disposed so as to face the surface.

  The heat generated by the LED is efficiently dissipated from the display panel case to the outside by bringing the LED substrate and the display panel case into close contact with each other. Display device can be obtained.

FIG. 1 is an exploded perspective view of a display device that is a guide light device, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 shows a state in which the display device of FIG. FIG.
As shown in FIGS. 1 and 2, the display device includes a display unit and a lighting control unit.
The display unit includes an LED 1 that is a light source, a light guide plate 4 that causes light of the LED 1 that is incident from one side surface that is the incident surface 4 a to be a surface light source, and that emits surface light from the front surface that is the irradiation surface 4 b; And a reflection plate 5 that reflects light emitted from the light guide plate 4 to the light guide plate 4 and a diffusion plate 6 that scatters the light from the light guide plate 4 to improve display characteristics and makes the directivity uniform. And a display pattern 7 for displaying a display pattern by irradiation from the rear diffusion plate 6 and a display plate case 8.
However, the reflecting plate 5 and the diffusing plate 6 may be omitted as appropriate, and a prism plate may be provided to improve the display surface brightness in place of the diffusing plate 6 in order to improve display characteristics.

Here, the LED 1 is mounted on the LED substrate 2, and the LED 1 and the LED substrate 2 are covered with an LED cover 3. The LED cover 3 has a back surface (a surface opposite to the display plate 7 side and a surface closed by the back surface of the display plate case 8 by fitting with the display plate case 8) and a lower surface (fitted to the display plate case 8). The LED substrate 2 has a back surface that is the back surface with respect to the mounting surface of the LED 1 so that the back surface is in close contact with the inner surface of the upper surface of the LED cover 3 (the surface facing the lower surface). Mounted on.
The LED substrate 2 is a paper phenol substrate, a glass epoxy substrate, a metal substrate such as aluminum, a ceramic substrate, or the like. Among these, in order to prevent high temperature due to heat generation of the LED 1, a metal substrate, a ceramic substrate, or the like with good thermal conductivity is desirable.
The light of the LED 1 can be effectively used by attaching a reflecting plate to the inner surface of the LED cover 3 or applying a reflective paint to make the inner surface a reflecting surface.
The light guide plate 4 is a plate-like body made of a transparent resin such as acrylic or polycarbonate, and the LED substrate 2 is disposed on one side surface of the light guide plate 4 so as to face the LED 1 to form an incident surface 4a. The light guide plate 4 has a light diffusion function for diffusing light propagating through the light guide plate 4 on at least one of the front irradiation surface 4b and the back surface. This light diffusing function is given by printing with white dots, roughening, or providing a prism.

The display panel case 8 has a rear surface (a surface on the opposite side to the display panel 7 side) of a hexahedron having an open front surface (a surface on the display plate 7 side) and an upper surface (a surface on the incident surface 4a side of the light guide plate 4). ) Is extended to the LED cover 3 side. It is fixed on one surface (the upper surface, the surface on the display board 7 side) of the appliance main body 9 constituting the lighting control section described later. In the display plate case 8, the reflection plate 5, the light guide plate 4, and the diffusion plate 6 are arranged and accommodated in this order toward the front surface direction (display plate 7 direction). Is closed by the display board 7 except for the upper part. Furthermore, by fitting the LED cover 3 having an L-shaped cross section, the opening on the upper surface of the display panel case 8 and the upper part of the opening on the front surface are closed. At this time, the extended back surface 9 a forms the back surface of the LED cover 3.
Therefore, the LED cover 3 is fitted into the opening on the upper surface of the display plate case 8 with the opening on the lower surface and united with the display plate case 8 to become an outer wall on the upper portion of the display plate case 8. Form a part of
Thus, since the LED cover 3 to which the LED board 2 is attached is attached to the opening of the display panel case 8 by fitting, the LED cover 3 can be easily attached and detached, and the LED 1 (or the LED board 2) can be easily attached. Exchange becomes easy.
In particular, the fitting of the LED cover 3 and the display plate case 8 is performed by the LED cover 3 without the back surface and the display plate case 8 having the extended back surface 9a, so there is no fitting on the back surface of the LED cover 3, The attachment / detachment of the LED cover 3 and the display panel case 8 is not limited to the upper surface lower surface direction, and can be performed in a wide range from the upper surface lower surface direction to the front surface rear surface direction, which is extremely easy. That is, the degree of freedom of attachment / detachment increases. Therefore, replacement of the LED 1 (or the LED substrate 2 on which the LED 1 is mounted) is extremely easy.

The lighting control unit includes a lighting control device (not shown) that controls lighting of the LED 1 that is a light source, and an appliance body 9 that accommodates the lighting control device.
The appliance main body 9 of the lighting control unit is arranged on the back side of the display plate case 8 and the LED cover 3 of the display unit as described above (FIGS. 1, 3, 4 (a) and (b)). In some cases, the LED cover 3 is accommodated inside and disposed on the upper part of the display panel case 8 (FIG. 4C).
Here, the surface light source device is configured by the LED 1, the LED substrate 2 on which the LED 1 is mounted, the reflection plate 5, the light guide plate 4, the diffusion plate 6, the LED cover 3, the display plate case 8, the lighting control unit, and the like. Further, the display device is configured by adding the display plate 7 to the surface light source device.
The display device can display various patterns by changing the display pattern of the display board 7. For example, if the display pattern is an evacuation guide pattern (design), the display device becomes a guide light device. It will be a guide. The display plate 7 may be a display element such as a liquid crystal display element that can change display contents (display pattern) in accordance with a video signal.
As shown in FIG. 3, this display device (guide light device) is mounted on a wall (an example of a wall-mounted type).

In such a display device (guide light device), the LED 1 of the light source is turned on by the lighting control device, the surface is illuminated by the light guide plate 4, the brightness is uniformed by the diffusion plate 6, and the display plate 7 is illuminated to display The display pattern of the board 7 is displayed.
At this time, heat generated by the lighting of the LED is transmitted to the LED substrate 2 via the LED lead and solder, and is transmitted to the LED cover 3 that is in close contact with the LED substrate 2. The LED cover 3 has an upper surface, side surfaces, and a front surface that are exposed to the outside as a part of the display panel case 8, and is cooled by external air using the heat radiation fins. Further, it is transmitted to the other display panel case 9 by the fitting portion and radiated. Therefore, the heat generated by the LED 1 can be efficiently dissipated, the temperature of the LED 1 can be prevented from rising, and the performance of the LED 1 can be prevented from being impaired.
As shown in FIGS. 1 and 2, the LED cover 3 and the LED substrate 2 are preferably in close contact with the entire surface of the LED substrate 2 in terms of heat transfer, but a heat dissipation effect can be ensured by adhering at least a part thereof.
The LED cover 3 and the display plate case 9 are formed of a resin plate such as ABS or polycarbonate or a metal plate. The resin plate is excellent in design, and the metal plate is excellent in terms of heat dissipation.

In addition to the wall-mounted type shown in FIG. 3, the display device can be variously attached as shown in FIG. 4, and can be selected depending on the use of the display device, the display location, and the like.
FIG. 4A shows a wall-embedded type in which the entire display case 8 and the back instrument body 9 are embedded in the wall. Moreover, FIG.4 (b) is a ceiling direct attachment type, and fixes the instrument main body 9 to a ceiling surface. FIG. 4 (c) shows a ceiling-embedded type in which an instrument body 9 that also houses an LED cover 3 is disposed in the upper part of the display panel case 8, and the instrument body 9 and the LED cover 3 are embedded in the ceiling. The display board 7 portion of the display board case 8 is protruded from the ceiling surface.
Although not shown in the drawing, the direct-ceiling type and the embedded-ceiling type may be a front and rear double-sided display type display device. The double-sided display type directly attached to the ceiling has display parts on the front and back sides (both sides) with the appliance main body 9 in between. The double-sided display type with a ceiling embedded type has a diffusion plate 6 and a display plate 7 on both sides of the light guide plate 4. Some have a display portion, and some have a display portion on the front and back.

The heat dissipation of the display device in the case of these attachments is as follows.
In the wall-embedded type, heat is radiated mainly from the front surface of the LED cover 3 to the outside. In the direct ceiling type, heat is radiated from the front and side surfaces of the LED cover 3 to the outside. In the ceiling-embedded type, the LED cover 3 is not exposed to the outside, but dissipates heat into the instrument body 9.

In order to dissipate the heat generated by the LED 1 through the LED substrate 2, instead of directly attaching the LED substrate 2 to the LED cover 3, a heat conducting member 10 may be interposed therebetween. Some examples are shown in FIG.
In FIG. 5A, the heat conducting member 10 is a flat plate and is brought into close contact with the inner surface of the upper surface of the LED cover 3, and the LED substrate 2, the heat conducting member 10 and the LED cover 3 are brought into close contact with each other.
5B, the heat conducting member 10 has an L-shaped cross section, one surface is in close contact with the inner surface of the upper surface of the LED cover 3, and the other surface is in close contact with the inner surface of the front surface, and FIG. 10 is L-shaped in cross section, one surface is in close contact with the inner surface of the upper surface of the LED cover 3, and the other surface is in close contact with the outer surface of the back surface of the display case 8, and FIG. One surface is in close contact with the inner surface of the upper surface of the LED cover 3, the other surface is in close contact with the inner surface of the front surface, and the other surface is in close contact with the outer surface of the back surface of the display case 8.

In any of these cases, the heat generated by the LED 1 is diffused to the heat conducting member 10 through the LED substrate 2 by bringing at least a part of the LED substrate 2 and the heat conducting member 10 into close contact with each other. To prevent. At the same time, at least part of the LED substrate 2 and the heat conducting member 10 and between the heat conducting member 10 and the LED cover 3 are brought into close contact with each other, whereby the heat generated by the LED 1 is transmitted through the LED substrate 2 and the heat conducting plate 10. Then, heat is radiated from the LED cover 3 and the display board case 8 (FIGS. 5A and 5B), or is radiated from the heat conducting member 10, the LED cover 3, and the display board case 8 through the LED substrate 2. (FIGS. 5C and 5D).
As the material of the heat conductive member 10, a metal such as a steel plate, aluminum, stainless steel, ceramics, or a filler-containing resin having good heat conductivity is used.
Further, the heat conducting member 10 is not provided as a separate member from the LED substrate 2, but the LED substrate 2 is a double-sided substrate, the copper foil on the back surface that is not the mounting surface is not patterned, and the copper foil is left as it is. A foil may be used as the heat conducting member 10. By using the double-sided substrate, it is not necessary to provide the heat conducting member 10 as a separate member, and there is a great merit in processing such as attachment. In this case, changing the shape and size of the heat conducting member 10 changes the shape and size of the double-sided substrate.

Here, the relationship between the mounting type of the display device shown in FIGS. 3 and 4 and the type of the heat conducting member 10 shown in FIG. 5 will be described.
In the wall-mounted type of FIG. 3, heat is radiated to the outside mainly from the top and front surfaces of the LED cover 3. Therefore, the heat conducting member 10 may be any of the flat plate, the front L shape, the rear L shape, and the U shape shown in FIGS. In the wall-embedded type of FIG. 4A, since the upper surface of the LED cover 3 is in the embedded state, heat is radiated mainly from the front surface, and a flat plate, a front L-shape, and a U-shape are good. In the ceiling-mounted type of FIG. 4B, the upper surface of the LED cover 3 is in close contact with or close to the ceiling. In the wall-embedded type and the ceiling-mounted type, it is desirable that a flat plate is in close contact with the front side of the LED cover 3. In the ceiling-embedded type in FIG. 4C, the LED substrate 2 and the LED cover 3 are both in the instrument main body 9 and are not exposed to the outside, so that heat is dissipated in the instrument main body. In this case, the heat conduction member 10 should be made as large as possible, and the U-shape that can be maximized is good. In this case, the LED cover 3 is preferably a metal plate regardless of design from the viewpoint of heat dissipation.
Basically, the size of the heat conducting member 10 is changed in consideration of the amount of heat to be diffused by the LED 1 and the amount of heat to be radiated. To increase the amount of heat to be diffused and the amount of heat released, increase it. Further, with the rear L-shape and the U-shape, the heat conducting member 10 can be extended to the size of the display plate case 8 at the maximum on the back side of the display plate case 8 without causing any problems in display and appearance.

The close contact method between the LED substrate 2 and the LED cover 3 and the close contact method between the LED substrate 2, the heat conducting member 10, and the LED cover 3 are firmly fixed with screws or rivets. Further, a spring may be used, or the adhesive may be adhered and fixed with a double-sided tape. When using an adhesive or double-sided tape, the thickness may be made as thin as possible, or thermal grease or silicone having good thermal conductivity may be used. A heat dissipation sheet or the like may be interposed.
The close contact position may be the inner surface of the front surface in addition to the inner surface of the upper surface of the LED cover 3.

  The LED substrate 2 on which the LED 1 is mounted is arranged so that the LED 1 faces the incident surface 4a of the light guide plate 4 directly on the inner surface of the upper surface of the LED cover 3 or via the heat conducting member 10, that is, the light emitting head of the LED 1. Is attached so as to face the incident surface 4a of the light guide plate 4 (FIGS. 1, 2, and 5). Instead, the LED 1 is placed on the inner surface of the front surface or the rear surface of the display plate case 8 on the inner surface of the rear surface. 4 may be mounted so as to face the light incident surface 4a, that is, so that the light emitting side portion of the LED 1 faces the light incident surface 4a of the light guide plate 4 (not shown). In this case, it is the same as the above that it is attached directly or via the heat conducting member 10 to the inner surface of the front surface of the display panel case 8 or the inner surface of the rear surface, and the display panel case 8 constitutes a part of the same. The LED cover 3 may be used. In these cases, it is advantageous to dissipate heat to the outside by attaching to the front surface. Further, in the case of mounting on the back surface, effective heat radiation is possible if heat radiation from the back surface is possible due to the structure and mounting type of the display device. Can be selected according to the mounting type.

  The display board case 8 is formed with the LED cover 3 whose upper wall is fixed to the inner surface of the display board case 8. The LED cover 3 is also formed of the display board case 8. The display case 8 is fixed so that at least a part thereof is in close contact with the inner surface of the case 8, and the display panel case 8 can be divided as appropriate for the convenience of component replacement, repair such as replacement of the LED board 2, and the like. It may be. When the heat conducting member 10 is used, the LED substrate 2 is brought into close contact with the heat conducting member 10 and the heat conducting member 10 is brought into close contact with the inner surface of the display panel case 8 as in the case of the LED cover 3.

  When the heat conducting member 10 is used, the LED substrate 2 is brought into close contact with the heat conducting member 10 and the heat conducting member 10 is brought into close contact with the inner surface of the display panel case 8 (LED cover 3). 10 may not necessarily be in close contact with the display panel case 8 (LED cover 3). By at least partially adhering the LED substrate 2 and the heat conducting member 10, cooling by heat diffusion of heat generation of the LED 1 and cooling by heat dissipation are possible. For example, in FIG. 5, the LED substrate 2 and the heat conducting member 10 are in close contact, but the heat conducting member 10 and the LED cover 3 may not be in close contact. In this case, the LED substrate 2 or the heat conducting member 10 is appropriately attached to the LED cover 3 by a known attachment method.

  The surface light source device of the present invention is used as an edge light type surface emitting display device for display devices such as a guide light device, an emergency light device, a road sign device, and an advertising light device.

It is a disassembled perspective view which shows an example of the display apparatus of this invention. It is the sectional view on the AA line of FIG. It is a figure which shows the state which attached the display apparatus of FIG. It is a figure which shows the state which attached the display apparatus of FIG. 1 separately. It is the sectional view on the AA line of the display apparatus using the heat conductive board of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED, 2 LED board, 3 LED cover, 4 Light-guide plate, 4a Incident surface, 4b Irradiation surface, 7 Display board, 8 Display board case, 10 Thermal conduction member.

Claims (9)

A plurality of LEDs that are light sources, an LED substrate on which the LEDs are mounted, a light guide plate that irradiates light from the light source incident from the incident surface of the side surface as a surface light source from an irradiation surface of the front surface, the LEDs, the LED substrate, and In a surface light source device including a display plate case that houses the light guide plate,
A surface in which the LED substrate is disposed so that at least a part of the LED substrate is in close contact with the inner surface of the display plate case, and the LED is opposed to an incident surface on a side surface of the light guide plate. Light source device.   The surface light source device according to claim 1, wherein at least a part of the LED substrate is in close contact with an inner surface of a front surface of the display panel case.   A heat conductive member is provided in the display board case, and at least a part is closely adhered between the LED board and the heat conductive member, and between the heat conductive member and the display board case, The surface light source device according to claim 1, wherein the display plate case is in close contact with the heat conductive member.   An opening is formed on the incident surface side of the light guide plate of the display plate case, and an LED cover that covers the LED and the LED substrate on which the LED is mounted is fitted into the opening, and the LED substrate is attached to the LED cover. The surface light source device according to any one of claims 1 to 3, wherein the heat conducting member is closely attached. A plurality of LEDs that are light sources, an LED substrate on which the LEDs are mounted, a light guide plate that irradiates light from the light source incident from the incident surface of the side surface as a surface light source from an irradiation surface of the front surface, the LEDs, the LED substrate, and In a surface light source device including a display plate case that houses the light guide plate,
A heat conductive member is provided in the display panel case, and the LED substrate is arranged such that at least a part of the LED substrate is in close contact with the heat conductive member, and the LED is opposed to an incident surface on a side surface of the light guide plate. A surface light source device characterized by comprising:   The surface light source device according to any one of claims 3 to 5, wherein a part of the heat conducting member is exposed to the outside of the display plate case.   The said LED board is formed with a double-sided board, The copper foil of the back surface of the said LED mounting surface of this double-sided board was used as the said heat conductive member, The claim in any one of Claims 3-6 characterized by the above-mentioned. Surface light source device.   A display device for forming a display pattern is provided, and the display plate is irradiated with the surface light source device according to any one of claims 1 to 7.   A guide lamp device, wherein the display pattern of the display device according to claim 8 is an evacuation guidance pattern.

Images