JP2002006759A - Surface light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface light source device which can effectively release the heat emitted by light sources to the outside and can emit the light of nearly uniformly intensity from the entire part of the front. SOLUTION: The front at the edge of a case 10 in common use as a reflector is provided with recessed parts 14 communicating with the inside and outside surfaces of the case. Vent ports 18 for releasing the heat generated by the light sources 15 arranged within the case to the outside by the spacings between the case and a diffusion plate 17 arranged to cover the open surface of the case are formed at the recessed parts 14 and the front of the case 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source device.

[0002]

2. Description of the Related Art Conventionally, as a surface light source device used for a backlight of an electro-optical display panel such as a liquid crystal display panel, there is a device having the following configuration.

FIG. 5 is a plan view of a conventional surface light source device, and FIGS. 6 and 7 are cross-sectional views taken along lines VI-VI and VII-VII of FIG. A reflector / case 1 and a light source 5 provided in the case 1
And a transparent plate 7 arranged on the front surface of the case 1 so as to cover its open surface.

The case 1 is a thin case made of, for example, a resin molded product and having a substantially rectangular planar shape. The entire inner surface of the case 1 is a reflective surface made of a deposited film or plated film of a metal having high reflectivity such as aluminum. (Not shown).

The light source 5 includes, for example, lead wires 6 at both ends.
The two U-shaped cold-cathode tubes 6 having a.a. are bent in the case 1 toward one end of the case 1 for discharge. The tube ends having electrodes (not shown) are arranged side by side with the end of the tube facing the other end of the case 1.

[0006] On the bottom surface 1a of the case 1, two continuous concave mirrors corresponding to the shapes of the two U-shaped cold cathode tubes 6 are formed. 1b is formed by extending the outer curved surfaces of the two concave mirror portions.

Further, the end surfaces 1c at both ends of the case 1,
1d are formed substantially perpendicularly to the front surface of the case, and a pair of arc-shaped ones respectively accommodating the bent portions of the two U-shaped cold cathode tubes 6 are provided on the inner surface of the end surface portion 1c at one end. A concave portion 2 is formed, and a plurality of concave portions 3 for accommodating the tube ends of the two U-type cold cathode tubes 6 are formed on the inner surface of the other end surface portion 1d.

Further, a lead outlet hole 4 opening to the outer surface of the case is provided on the inner bottom surface of the plurality of recessed portions 3, and lead wires 6 a of the two U-shaped cold cathode tubes 6 are provided.
Is a circuit board 9 which is led out of the case through the lead lead-out hole 4 and has a light source driving circuit and the like formed behind the case 1 and arranged as shown by a virtual line (two-dot chain line) in FIG.
Connected to.

The transparent plate 7 arranged on the front surface of the case 1 so as to cover the open surface is, for example, a diffusion plate. The diffusion plate 7 is formed by connecting its peripheral edge to the peripheral edge of the case 1 (on both sides). It is fixed to the front surface of the case 1 by being attached to the front surface of the side surface portion 1b and the end surface portions 1c, 1d) at both ends with a double-sided adhesive tape or the like (not shown) or by screwing.

In the surface light source device, the heat generated by the U-type cold cathode tube 6 provided as the light source 5 is accumulated in the case 1 and the whole surface light source device is heated. It is transmitted to an electro-optical display panel (not shown) such as a liquid crystal display panel disposed on the front side, and changes the electro-optical characteristics of the display panel.

Since the surface light source device is not completely closed, the lead-out hole 4 provided in the end surface 1d of the case 1 is open to the outer surface of the case. The heat generated by the lead-out hole 4 can be radiated to the outside through the lead-out hole 4 to some extent. However, the heat released from the lead-out hole 4 is heat near the tube end of the U-type cold cathode tube 6. Most of the heat generated by the U-type cold cathode tube 6 is stored in the case 1.

For this reason, in the conventional surface light source device, as shown in FIGS. 5 and 6, a slit-shaped ventilation opening along the case length direction is provided at an appropriate position on the bottom surface 1a or the side surface 1b of the case. 8 and the case 1
The internal heat is released to the outside.

[0013]

However, as described above, the conventional surface light source device provided with the ventilation port 8 on the bottom portion 1a or the side portion 1b of the case as described above emits the light from the light source 5 to the case 1
Of the light traveling toward the inner surface (anti-slope surface), the light traveling toward the ventilation port 8 leaks from the ventilation port 8 to the rear side of the surface light source device.

Therefore, in the above-mentioned conventional surface light source device, the light emitted to the front surface (superimposed light of the light emitted directly from the light source 5 to the front surface and the light reflected by the inner surface of the case 1) is transmitted to the ventilation port. 8, the intensity of the portion corresponding to 8 becomes light having an extremely low intensity distribution, and there is a problem that the display quality of the display panel arranged on the front side of the light source device is deteriorated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface light source device capable of effectively emitting heat generated by a light source to the outside and emitting light having a substantially uniform intensity distribution from the entire front surface. is there.

[0016]

A surface light source device according to the present invention is provided with a reflector / case having an open front surface, a light source provided in the case, and a front surface of the case covering the open surface. A concave portion communicating with the inner and outer surfaces of the case is provided on a front surface of at least one edge of the case; and a gap between the concave portion and the transparent plate allows heat generated by the light source to be externally formed. A vent for discharging the air to the air.

Since the surface light source device has the ventilation hole, the heat generated by the light source can be effectively released to the outside. Moreover, the surface light source device is provided with a concave portion communicating with the inner and outer surfaces of the case on the front surface of at least one edge of the case, and the concave portion and the transparent plate disposed on the front surface of the case so as to cover the open surface thereof. Since the ventilation hole is formed by the gap between the light sources, the intensity of light emitted to the front of the surface light source device is reduced only in the vicinity of the edge of the case where the concave portion is provided. Therefore, light having a substantially uniform intensity distribution can be emitted from the entire front surface.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the surface light source device of the present invention is provided with a recess communicating with the inside and outside of the case at the front surface of at least one edge of the reflector case, and at the recess and the front surface of the case. By forming a ventilation opening by a gap between the transparent plate disposed over the open surface, the heat generated by the light source disposed in the case is effectively released to the outside, and from the entire front surface. In this configuration, light with a substantially uniform intensity distribution can be emitted.

In the surface light source device according to the present invention, it is preferable that the depth of the concave portion forming the ventilation port is 2 mm or less, and if the depth of the concave portion is about this, the concave portion of the case is provided. A decrease in the intensity of the outgoing light generated near the set edge is hardly noticeable, and light having a substantially uniform intensity distribution can be emitted from the entire front surface.

Further, the concave portion forming the ventilation port,
Although it may be provided at any edge of the peripheral edge of the case, for example, the planar shape of the case is substantially rectangular,
In the case where recesses are formed on the front surfaces of the edges on both sides of the case over substantially the entire length thereof, it is preferable that the depth of the recesses be approximately 1 mm, so that sufficient heat dissipation is achieved. In addition to obtaining the effect, it is possible to make the intensity of the outgoing light generated near the edge of the case where the concave portion is provided inconspicuous, and to emit light having a substantially uniform intensity distribution from the entire front surface.

[0021]

1 to 4 show one embodiment of the present invention. FIG. 1 is a plan view of a surface light source device, and FIGS.
FIG. 4 is a sectional view taken along lines II-II and III-III of FIG.
FIG. 4 is an enlarged view of an IV part of FIG.

The surface light source device of this embodiment includes a reflector / case 10 having an open front surface, a light source 15 provided in the case 10, and a transparent light source disposed on the front surface of the case 10 so as to cover the open surface. It consists of a plate 17.

The case 10 is a thin case made of, for example, a resin molded product and having a substantially rectangular planar shape. The entire inner surface of the case 10 is a reflective surface made of a deposited film or a plated film of a metal having high reflectivity such as aluminum. (Not shown).

The light source 15 is composed of, for example, two U-shaped cold cathode tubes 16 having lead wires 16a at both ends. They are arranged side by side with the bent portion facing one end of the case 10 and the tube end having a discharge electrode (not shown) facing the other end of the case 10.

The bottom surface 10a of the case 10 is formed with two consecutive concave mirrors corresponding to the two U-type cold cathode tubes 15, respectively.
The side portions 10b on both sides of the “0” are formed by extending the outer curved surfaces of the two concave mirror portions, respectively.

Further, the end faces 10 at both ends of the case 10
Each of c and 10d is formed substantially perpendicular to the front surface of the case.
A pair of arc-shaped concave portions 11 for accommodating the bent portions of the two U-shaped cold cathode tubes 16 are formed, and the end surface portion 1 at the other end is formed.
On the inner surface of Od, a plurality of recessed portions 12 for accommodating the tube ends of the two U-shaped cold cathode tubes 16 are formed.

Further, a lead lead-out hole 13 is formed at the inner bottom surface of the plurality of recessed portions 12 and opens to the outer surface of the case, and the lead wires 16a of the two U-shaped cold cathode tubes 16 are 3 is drawn out of the case from the lead lead-out hole 4 and is indicated by an imaginary line (two-dot chain line) in FIG.
Is connected to the circuit board 19 on which the light source drive circuit and the like arranged as shown by the symbol are formed.

The transparent plate 17 disposed on the front surface of the case 10 so as to cover the open surface is, for example, a diffusion plate. Side face part 10b and end face parts 10 at both ends
(c, 10d) is attached to the front surface of the case 10 with a double-sided adhesive tape or the like (not shown) or fixed to the front surface of the case 10 by screws.

On the other hand, at the front of at least one edge of the case 10, a concave portion 14 communicating with the inner and outer surfaces of the case is provided. A ventilation port 18 for discharging heat generated by the light source 15 including the U-shaped cold cathode tube 16 to the outside is formed.

In this embodiment, the recesses 14 forming the ventilation holes 18 are formed on the front surfaces of both edges of the case 10 over substantially the entire length thereof, and the depth h of the recesses 14 is formed. Is set to approximately 1 mm, so that slit-shaped ventilation holes 18 having a width of approximately 1 mm are formed on both side edges of the case 10 over the entire length thereof.

Since this surface light source device is provided with the ventilation port 18, the air in the case 10 heated by the heat generated by the light source 15 is discharged from the ventilation port 18 to the outside, and the external air is released. The case 10 from the ventilation port 18
Therefore, the heat generated by the light source 15 can be effectively released to the outside.

In addition, this surface light source device is
A concave portion 14 communicating with the inner and outer surfaces of the case is provided on the front surface of the edge portion of the case 10, and the ventilation port is formed by a gap between the concave portion 14 and the diffusion plate 17 disposed on the front surface of the case 10 so as to cover the open surface. 18, the intensity of light emitted to the front of the surface light source device (superimposed light of light emitted directly from the light source 15 to the front and light reflected by the inner surface of the case 10) decreases. It only occurs near the edge of the case 10 where the concave portion 14 is provided, so that light with a substantially uniform intensity distribution can be emitted from the entire front surface.

That is, of the light emitted from the light source 15 and directed to the inner surface (anti-slope) of the case 10, the light directed to the ventilation port 18 leaks from the ventilation port 18 to the outside. In the light source device, the ventilation port 18 is formed by a gap between the diffusion plate 17 disposed on the front surface of the edge of the case 10 and the diffusion plate 17 disposed on the front surface of the case 10 so as to cover an open surface thereof. Therefore, a decrease in the intensity of outgoing light due to light leakage from the ventilation port 18 is as follows:
It only occurs near the edge of the case 10 where the concave portion 14 is provided, that is, near the edge of the diffusion plate 17 disposed on the front surface of the device.

Therefore, according to this surface light source device, it is possible to emit light having a substantially uniform intensity distribution from the entire front surface thereof. Therefore, an electro-optical display such as a liquid crystal display panel disposed on the front side of the light source device is provided. Light having a substantially uniform intensity distribution is incident on a panel (not shown), and an image of good quality without luminance unevenness can be displayed on this display panel.

In the surface light source device of this embodiment, the recesses 14 are provided on the front surfaces of the edges on both sides of the case 10 over substantially the entire length thereof.
By making the depth h approximately 1 mm, the case 1
Since the slit-shaped ventilation holes 18 having a width of approximately 1 mm are formed on both side edges of the zero-length side, a sufficient amount of air is circulated through the ventilation holes 18 to obtain a sufficient heat radiation effect. Can be.

In addition, in the surface light source device of this embodiment, since the depth h of the concave portion 14 is extremely small, approximately 1 mm, the emitted light generated near the edge of the case 10 where the concave portion 14 is provided. Is only generated over a width of about 1 mm in the vicinity of the edge of the diffusion plate 17, and therefore, the intensity of the outgoing light generated near the edge of the case 10 where the recess 14 is provided is reduced. To make it less noticeable,
Light with a substantially uniform intensity distribution can be emitted from the entire front surface.

In the above embodiment, the recesses 14 forming the ventilation holes 18 are provided on the front surfaces of the edges on both sides of the case 10 over substantially the entire length thereof. , May be provided at any one of the peripheral edges of the case 10.
It may be provided intermittently at intervals in the length direction of the 0 edge.

However, in order to effectively discharge the air inside the case 10 heated by the heat generated by the light source 15 to the outside and to effectively take in the outside air into the case 10, a ventilation port 18 is formed. The recess 14 is preferably provided at least on the front side of the edges of the two sides of the case 10, preferably the two sides facing each other.

In the above embodiment, the depth h of the concave portion 14 forming the ventilation port 18 is set to approximately 1 mm.
The depth h of the concave portion 14 may be selected according to the length of the concave portion so as to form a ventilation port having a sufficient area.

However, the concave portion 1 forming the ventilation port 18
4 is preferably 2 mm or less, and if the depth of the concave portion 14 is about this, the intensity of the emitted light generated near the edge of the case 10 where the concave portion 14 is provided. The decrease is hardly noticeable, and light with a substantially uniform intensity distribution can be emitted from the entire front surface.

The surface light source device of the above embodiment is provided with a light source 15 comprising two U-shaped cold cathode tubes 16, and the light source 16 comprises, for example, a plurality of straight tube cold cathode tubes. The reflector and the case 10 may be of any shape as long as the front surface is open and the inner surface is a reflection surface.

Further, in the above embodiment, the case 10
Although the transparent plate 17 disposed on the front surface of the display panel so as to cover the open surface is a diffusion plate, for example, when the diffusion plate is provided on the back surface of the display panel disposed on the front side of the surface light source device,
The transparent plate 17 may be non-diffusing.

[0043]

According to the surface light source device of the present invention, a concave portion communicating with the inner and outer surfaces of the case is provided on the front surface of at least one edge of the reflector / case, and the concave surface and the front surface of the case are arranged so as to cover the open surface. Since the ventilation hole is formed by the gap between the transparent plate and the transparent plate, the heat generated by the light source disposed in the case is effectively released to the outside, and the intensity distribution is substantially uniform from the entire front surface. Of light can be emitted.

In the surface light source device according to the present invention, it is preferable that the depth of the recess forming the ventilation hole is 2 mm or less, and if the depth of the recess is about this, the recess of the case is provided. A decrease in the intensity of the outgoing light generated near the set edge is hardly noticeable, and light having a substantially uniform intensity distribution can be emitted from the entire front surface.

The recess forming the ventilation port is
Although it may be provided at any edge of the peripheral edge of the case, for example, the planar shape of the case is substantially rectangular,
In the case where recesses are formed on the front surfaces of the edges on both sides of the case over substantially the entire length thereof, it is preferable that the depth of the recesses be approximately 1 mm, so that sufficient heat dissipation is achieved. In addition to obtaining the effect, it is possible to make the intensity reduction of the outgoing light generated near the edge of the case where the concave portion is provided inconspicuous, and to emit light having a substantially uniform intensity distribution from the entire front surface.

[Brief description of the drawings]

FIG. 1 is a plan view of a surface light source device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is an enlarged view of a portion IV in FIG. 2;

FIG. 5 is a plan view of a conventional surface light source device.

FIG. 6 is a sectional view taken along the line VI-VI of FIG. 4;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Case 14 ... Concave part 15 ... Light source 17 ... Diffusion plate (transparent plate) 18 ... Ventilation port

Claims (3)

[Claims] 1. A reflector double-purpose case having an open front surface,
A light source provided in the case and a transparent plate disposed on the front surface of the case so as to cover the open surface thereof, and a concave portion communicating with the inner and outer surfaces of the case is provided on the front surface of at least one edge of the case. The surface light source device is provided, wherein a ventilation hole for releasing heat generated by the light source to the outside is formed by a gap between the concave portion and the transparent plate. 2. The surface light source device according to claim 1, wherein the depth of the concave portion forming the ventilation port is 2 mm or less. 3. The case has a substantially rectangular planar shape, and a concave portion for forming a ventilation port is provided on substantially the entire front surface of each of the edges on both sides of the case.
The surface light source device according to claim 1, wherein the depth of the concave portion is approximately 1 mm.