Lighting device having surface light source panels

Provided is a lighting device having high luminance in-plane uniformity without a dark part occurring at a connecting part between surface light source panels.The lighting device (1) is provided with a plurality of surface light source panel (2), and a plurality of light diffusion passive reflectors (3) disposed at the light-emitting side of the surface light source panel (2). In the light diffusion passive reflector (3), a rectangular-shaped bottom surface is disposed on a light emitting region of the surface light source panel (2), and a light-emitting surface (3a) has substantially the same size as a planar outline of the surface light source panel (2), and a side surface (3c) is formed to incline diagonally outward towards the light-emitting surface (3a) from the bottom surface. The light diffusion passive reflectors (3) which are mutually adjoining are disposed to contact with each other without a gap in between, and are disposed so that the light-emitting surface (3a) is continuously arranged.

TECHNICAL FIELD

The present invention relates to a lighting device. More particularly, the present invention relates to a lighting device having a plurality of surface light source panels.

BACKGROUND ART

Conventionally, a surface light source panel (lighting device) as shown inFIG. 1(a) is known (for example, refer to Patent Literature 1). As for such a surface light source panel100, a layered structure (not shown) of an anode, an organic electroluminescence layer and a cathode intervenes between a transparent substrate101and a sealing substrate102. Moreover, a sealing member103is formed to surround internal space between the edge parts of the transparent substrate101and the sealing substrate102.

In recent years, as shown inFIG. 1(b), an effort to produce a pseudo-large-sized lighting device110is performed by arranging a plurality of comparatively small surface light source panels100in two dimensions. Thus, the reason for producing by using the plurality of surface light source panels100is that it takes into consideration for the manufacturing yield of the surface light source panel100. That is, it is because the rate which becomes a defective product including a defect in proportion to size will increase and the yield will worsen, when producing a large-sized lighting device by using a single surface light source panel100.

DISCLOSURE OF INVENTION

Technical Problem

However, when the large-sized lighting device110is produced by arranging a plurality of surface light source panels100in two dimensions, there are problems which will be explained hereinafter.

That is, since the sealing member103is formed in frame shape to surround the light emitting region104in each surface light source panel100as shown inFIG. 1(a), a sealing area105formed of the sealing member103exists as a region which does not emit light, naturally. As shown inFIG. 1(b), since a boundary (connecting part) between the surface light source panels100which are mutually adjoining, the sealing area105located at the periphery of the lighting device110, etc. are darkly conspicuous, it was difficult to produce the large-sized lighting device110for achieving surface light uniformly. In particular, there was a problem that a wide dark part will be formed, since the sealing areas105of both surface light source panels100are mutually adjoining on the boundary between the surface light source panels100.

Moreover, when the large-sized lighting device110is produced by arranging a plurality of surface light source panels100in two dimensions, it is requested for having a function which can be bent or curved on the light-emitting surface. However, there was a problem that the dark part of boundary part and peripheral edge part between the surface light source panels100is conspicuous since the sealing area105exists as well as the above-mentioned lighting device110, and it was difficult to utilize until the problem that a gap occurs between the surface light source panels100by being bent or curved is solved.

The principal purpose of the present invention is to provide a lighting device having high luminance in-plane uniformity, without a dark part occurring at a connecting part between surface light source panels.

Moreover, another purpose of the present invention is to provide a lighting device which can be bent or curved and also a dark part does not occur at a boundary part, etc. between surface light source panels.

Solution to Problem

Then, in the characteristic of the present invention, the summary is to comprising: a plurality of surface light source panels disposed to be mutually adjoining in two dimensions; and a plurality of light diffusion passive reflectors including a side surface and a light-emitting surface, a bottom surface being disposed on a surface of a light emitting region in each the surface light source panel, the side surface acting as a reflection mirror surface formed to incline towards a diagonal outside at a side of a light-emitting direction from the bottom surface, the light-emitting surface emitting an emitted light from the light emitting region and a reflected light from the side surface, a plurality of the light diffusion passive reflectors being disposed to be mutually adjoining without a gap in between and to form a continuous face.

In this case, as for the light diffusion passive reflector, it is preferred that a part located outside of an outline at the bottom surface of the light diffusion passive reflector is transparent. Thus, by making transparent the part of the light diffusion passive reflector located at the outside of an outline at the bottom, i.e., the outside of the light emitting region, the amount of light-emitting in the region which is not emitting light outside of the light emitting region can be decreased, and the luminance in-plane uniformity of the lighting device can be further improved.

Moreover, it is effective also as a configuration that a part located outside of an outline at the bottom surface of the light diffusion passive reflector is transparent. According to such a configuration, a curved light-emitting surface can be achieved as the lighting device, and it is possible to generate a light effect corresponding to the surrounding environment.

Furthermore, a plurality of the surface light source panels may be disposed to be mutually adjoining in two dimensions, may be provided along with a plurality of electrode plates mutually connected so that curvature is possible, and can be curved at a boundary part corresponding to the curvature of the electrode plate.

Moreover, it is effective also as a configuration that the surface light source panels adjoining mutually is connected with each other by supporting a free end of a pair of universal links rotatably at a backside, respectively, and is abutted on an edge part between the light diffusion passive reflectors in the state to be curved mutually.

Furthermore, it is preferred that the light-emitting surface of the light diffusion passive reflector has light diffusion structure. Accordingly, since the light is diffused on the light-emitting surface when the light from the light emitting region and the reflected light from the side surface reach the light-emitting surface, the visual angle dependency of luminance and chromaticity can be reduced, and the angle of visibility can be decreased. As the light diffusion structure, for example, it may be suitable for a roughened surface formed by performing the surface roughening of the light-emitting surface, and may be suitable for a structure formed by bonding the light diffusing films each other.

Advantageous Effects of Invention

According to the present invention, since the light is guided from the light emitting region side to the part located on the non-light emitting region of the surface light source panel in the light diffusion passive reflector, the luminance in-plane uniformity can be improved as the whole lighting device.

In particular, according to the present invention, since it can suppress that the dark part occurs at the boundary part between the surface light source panels even if the surface light source panels are disposed in two dimensions without limitation of a number, it becomes possible to build the lighting device composed of the optically unified large-sized surface light source.

REFERENCE SIGNS LIST

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the details of lighting devices according to embodiments of the present invention will be explained based on drawings.

A lighting device1according to a first embodiment of the present invention will be explained usingFIG. 2andFIG. 3.

(Schematic Structure of Lighting Device)

As shown inFIG. 2, the lighting device1according to the present embodiment is substantially composed by including a plurality of surface light source panels2, and a plurality of light diffusion passive reflectors3disposed at the light-emitting side of the surface light source panel2.

(Configuration of Surface Light Source Panel)

In the surface light source panel2, layered structure (not shown), such as an anode, an organic electroluminescence layer and a cathode, intervenes between a transparent substrate and a sealing substrate5of rectangular shape having substantially the same size, respectively. Moreover, a sealing member (not shown) is provided to surround internal space between the edge parts of the transparent substrate4and the sealing substrate5. In addition, the configuration of the surface light source panel2according to the present embodiment is the same configuration as the surface light source panel shown inFIG. 1(a). Moreover, as shown inFIG. 2, the surface light source panels2are disposed and fixed on a supporting substrate (not shown) so that a gap does not occur vertically and horizontally in two dimensions.

(Configuration of Light Diffusion Passive Reflector)

The light diffusion passive reflector3composes an acrylic board having a light diffusing function, for example. As shown inFIG. 3(a) andFIG. 3(b), the structure of the light diffusion passive reflector3is a trapezoidal shaped plate structure with the larger size of a light-emitting surface3athan the size of a bottom surface3b. More specifically, the bottom surface3bof rectangular shape is set as the same size as the light emitting region A1of the surface light source panel2to conform with the light emitting region A1, or is set up a little more largely to cover the light emitting region A1completely. Moreover, the light-emitting surface3awhich is parallel to the bottom surface3bhas substantially the same size as the planar outline of the surface light source panel2as shown inFIG. 3(a), and is set up so that the outline of the light-emitting surface3aoverlaps with the surface light source panel2substantially as shown inFIG. 3(b) when observed from the plan surface. A side surface3cbetween the sides corresponding to the light-emitting surface3aand the bottom surface3b, respectively is formed to incline diagonally outward from the bottom surface3btowards the light-emitting surface3a. That is, as shown inFIG. 3(a), the edge part of the light diffusion passive reflector3is formed to be overhang-shaped. In the present embodiment, the angle θ between the side surface3cand the surface of the surface light source panel2is set up in the range of 45±10 degrees

In addition, what is necessary is just to optimize arbitrarily the raise degree of this light diffusion passive reflector3depending on the size and the level to diffuse of the surface light source panel2, and the emitted light intensity from the surface light source panel2side, etc. In addition, the light diffusion passive reflector3is preferable to be formed by resin, such as acrylic, as mentioned above, but it is also possible to use a glass etc. having a light diffusing function which is cloudy on the inside.

As mentioned above, a plurality of surface light source panel2is disposed and fixed on the supporting substrate (not shown) each other so that a gap may not occur vertically and horizontally in two dimensions in between. Therefore, as shown inFIG. 2, the light diffusion passive reflector3disposed on the surface light source panel2is also disposed to be mutually adjoining so that a gap does not occur vertically and horizontally.

(Operation of Lighting Device)

When each surface light source panel2composing the lighting device1is driven, light is emitted from the light emitting region A1of the surface light source panel2to the light diffusion passive reflector3side. In the light diffusion passive reflector3, light is diffused to a part located just above the light emitting region A1. It is the same even when the light diffusion passive reflector which does not have the inclining side surface3cis used.

As shown inFIG. 3(a), since the non-light emitting region A2of the surface light source panel2originally does not emit light, the non-light emitting region A2is a region which is a dark part if the light diffusion passive reflector3is not formed. However, in the present embodiment, since the side surface3cof the light diffusion passive reflector3is disposed correspond to the non-light emitting region A2, the light which is diffused within the light diffusion passive reflector3and travels to the side surface3c, and the light which travels to the side surface3cdirectly from the light emitting region A1are reflected on the light-emitting surface3aside because the side surface3cfunctions as a reflection mirror. Thus, since the light is also emitted from the light-emitting surface3aon the non-light emitting region A2of the boundary part between the surface light source panels2, the non-light emitting region A2is not recognized visually as a dark part. It becomes possible to set the regions correspond to the light emitting region A1and the non-light emitting region A2in the light-emitting surface3aas equivalent luminance each other, by calibrating the angle of gradient θ of the side surface3cof the light diffusion passive reflector3, and compounding of diffusing function particles etc.

In the above, the configuration of the lighting device1according to the first embodiment has been explained. Such a lighting device1has one optically unified light-emitting surface without a connecting part in appearance using a plurality of surface light source panels2.

As for the surface light source panel2, the defect increases and the yield deteriorates in proportion to the emission area. However, in the present embodiment, the large-sized lighting device1having high luminance in-plane uniformity can be achieved by using a plurality of small-sized surface light source panels2having satisfactory yield.

Since the connecting part between the surface light source panels2does not act as a dark part when the lighting device1according to the present embodiment is used, for example as a backlight of a liquid crystal display device, the high quality liquid crystal display device is achievable.

In addition, although the example which used organic electroluminescence material for the surface light source panel2has been explained in the present embodiment, it is not limited to the above-mentioned configuration if it is the material which performs surface light emission. There is the surface light source panel which used an inorganic electroluminescence material other than the organic electroluminescence material, for example.

(Modified Example of Light Diffusion Passive Reflector)

FIG. 4(a) andFIG. 4(b) show a modified example of a light diffusion passive reflector3according to the first embodiment. The light diffusion passive reflector3is formed as a transparent area3dwhich is a transparent part outside from the bottom surface3b, when observed from the plan surface. Moreover, the surface roughness is increased on the light-emitting surface3ain order to improve the light diffusing function.

The light diffusion passive reflector3according to the modified example becomes advantageous when the gradient is gentle so that the angle of gradient θ of the side surface3cis not more than 45 degrees. That is, when the gradient of the angle of gradient θ is gentle, the light does not reach to the side surface3ceasily directly from the light emitting region A1of the surface light source panel2, and little light diffused within the light diffusion passive reflector3just above the light emitting region A1reaches. In this case, if a part corresponding to the non-light emitting region A2in the light diffusion passive reflector3is cloudy by particles for light diffusion, optical loss becomes large and the non-light emitting region A2which is an adjoining part between the surface light source panels2becomes dark easily. Accordingly, it becomes advantageous since the optical loss decreases by forming such part by the transparent area3d.

Moreover, as mentioned above, since the surface roughness is increased on the light-emitting surface3a, the whole light-emitting surface3abecomes a light diffusing surface, and the boundary between the transparent area3din the light-emitting surface3aof the light diffusion passive reflector3and the other part is formed indistinctly, and it can contribute to improvement in luminance in-plane uniformity.

According to the first embodiment, since the light is guided from the light emitting region side and the light is emitted from the direct light-emitting surface3a, or the light reflected on the side surface3cis emitted, on the part located on the non-light emitting region (for example, the region in which the sealing member is formed and the peripheral edge part) of the surface light source panel2in the light diffusion passive reflector3, the luminance in-plane uniformity can be improved as whole the lighting device1. Therefore, according to the first embodiment, the one piece continuous face optically can be formed.

Hereinafter, a lighting device10according to a second embodiment of the present invention will be explained usingFIG. 5(a) toFIG. 5(c).

As shown inFIG. 5(a) toFIG. 5(c), the lighting device10according the present embodiment is substantially composed by including a plurality of surface light source panels11, a light diffusion passive reflector12which is the same number as the surface light source panel11formed on the surface (adverse side) at the each light-emitting side of the surface light source panels11, a heat sink plate13which is the same number as the surface light source panel11formed on the backside of the surface light source panel11, and a universal link14for connecting the heat sink plates13each other which are mutually adjoining so that curvature is possible.

Since the surface light source panel11is the same as that of the surface light source panel2according to the above-mentioned first embodiment shown inFIG. 3(a) andFIG. 3(b), the explanation is omitted.

According to the present embodiment, the light-emitting surface12aof the light diffusion passive reflector12is set as larger size than the heat sink plate13and the surface light source panel11. That is, the periphery of the light-emitting surface12ais set up to be located outside of the outline by the plane view of the heat sink plate13and the surface light source panel11. In addition, other configurations in the light diffusion passive reflector12are the same as that of the above-mentioned first embodiment, and have the side surface12cfor functioning as the bottom surface12band the reflection mirror.

Moreover, in the present embodiment, the surface light source panel11and the light diffusion passive reflector12are formed on each of the heat sink plate13adjoining mutually and connecting mutually so that curvature is possible, instead of the configuration which disposes and fixes the surface light source panel11on the flat surface of the supporting substrate such as the above-mentioned first embodiment.

In this case, the heat sink plates13are connected with each other with universal links14, as shown inFIG. 5(a) toFIG. 5(c). In the universal link14, a pair of arm units14ais supported pivotally between ends of one side with an axis of rotation14brotatable. Ball parts14chaving spherical surfaces are formed at the free ends of a pair of the arm units14a. The ball parts14care supported by the backside of the heat sink plate13rotatable. In addition, in the present embodiment, although the example in which the ball part14cis embedded under the backside of the heat sink plate13rotatable is shown, it may allow to curve along the conic surface etc. except the spherical surface.

According to the present embodiment, the arm unit14abecomes freely swingable for the backside of the heat sink plate13by using the ball part14cas a fulcrum. By using such a universal link14, the distance between the heat sink plates13can be changed by changing the distance between the ball parts14cof a pair of the arm units14a. As a result, a continuous face can be formed in the condition that the light-emitting surfaces12aof the light diffusion passive reflectors12mutually adjoining are mutually curved each other, in the state to contact between the edge parts of the light diffusion passive reflector12so that a gap does not occur in between.FIG. 5(a) shows the state where a plurality of light-emitting surfaces12aforming the continuous face are made curved to become a convex as a whole.FIG. 5(b) shows the state where a plurality of light-emitting surfaces12aforming the continuous face are calibrated to become a flat surface as a whole.FIG. 5(c) shows the state where a plurality of light-emitting surfaces12aforming the continuous face are made curved to become a concave as a whole.

In the present embodiment, since the angle can be relatively changed arbitrarily between the adjoining light diffusion passive reflectors12of the light-emitting surface12awhich forms the continuous face, it is possible to produce easily the lighting device10of shape corresponding to an intended use.

The lighting device10according to the present embodiment can also be made into one optically unified light-emitting surface without a connecting part in appearance using a plurality of surface light source panels11.

When the lighting device10according to the present embodiment is used, for example as a decorative sign backlight, it is possible to change it to arbitrary shape corresponding to environment, since it can be disposed inside the cylindrical decorative sign in the condition that the lighting device10itself is also made cylindrical. Also in the present embodiment, since the connecting part between the surface light source panels12does not become a dark part, it can be made as the lighting having high display quality.

MODIFIED EXAMPLE 1 OF CONNECTING STRUCTURE

Although the second embodiment shows the configuration which connected the heat sink plate13each other with the universal link14, a plurality of base plates15for supporting the surface light source panel are prepared in order to connect between the base plate15adjoining mutually with the universal link16, as shown inFIG. 6(a) andFIG. 6(b). Since the universal link16shown inFIG. 6(a) andFIG. 6(b) is almost the same about the point that the ball part16b is supported by the backside of the heat sink plate13swingable and other functions except that the shape of the universal link14and the arm unit16a shown inFIG. 5(a) toFIG. 5(c) differs, the detailed explanation is omitted. In addition, in the modified example shown inFIG. 6(a), the universal link16is provided in the part where the side of the x direction and y direction shown inFIG. 6(a) by an arrow is mutually adjoining, respectively so that the base plates15can be curved each other by a column unit or a row unit.

In the modified example 1, the lighting device having the same function as the above-mentioned second embodiment is achievable by disposing the surface light source panel and the light diffusion passive reflector on the surface of the base plate15.

MODIFIED EXAMPLE 2 OF CONNECTING STRUCTURE

FIG. 7andFIG. 8show a modified example 2 of the connecting structure. The modified example 2 is an example which disposes a plurality of rectangular-shaped electrode plates17vertically and horizontally in two dimensions, and connects between the sides adjoining and opposing to the height or width of the electrode plates17adjoining mutually via the hinge region18so that curvature is possible. As shown inFIG. 7andFIG. 8, in the modified example 2, the surface light source panel11is formed to range over between the electrode plates17adjoining mutually without being connected with the hinge region18. Moreover, as shown inFIG. 7, the heat sink plate13is formed to accompany the backside of the electrode plate17. In addition, in the modified example 2, the surface light source panel11is disposed to range over between the electrode plates17adjoining mutually, but may be disposed so that the outlines overlaps each other over the front side of the electrode plate17mostly.

In the above-mentioned modified example 2 of the connecting structure, the lighting device with which the light-emitting surfaces can be curved mutually is achievable by disposing the same light diffusion passive reflector as the above-mentioned second embodiment on the surface light source panel11.

According to the above-mentioned second embodiment, since it can suppress that the dark part occurs in the boundary part between the surface light source panels11even if the surface light source panel11is disposed in two dimensions without limitation of a number, it is possible to build the lighting device10which is the optically unified large-sized surface light source.

The present invention is not to be considered limited to apart of disclosure of the above-mentioned embodiments including associated description and drawings. With the disclosure, artisan might easily think up alternative embodiments, embodiment examples, or application techniques.

For example, in the above-mentioned first and second embodiments, although a plurality of surface light source panels2and11, the heat sink plate13, the base plate15, the electrode plate17, etc. are set to have substantially the same size, it is effective also as a configuration to mix a element from which a vertical and horizontal dimension differs partially. In particular, in the above-mentioned second embodiment, it is also possible to form the continuous face approximated to a curved surface by setting the surface light source panel etc. of the curved part as narrow width.

Moreover, in the above-mentioned first embodiment, although the angle θ between the side surface3cof the light diffusion passive reflector3and the surface of the surface light source panel2is set up the range of 45±10 degrees, it is not limited to such configuration. What is necessary is just to set up suitably according to various kinds of conditions of the width dimension and materials etc. of the light diffusion passive reflector3.

Furthermore, although the above-mentioned first embodiment has explained the example to increase the surface roughness on the light-emitting surface3a, it may be suitable for a structure to bond the light scattering film on the light-emitting surface3amutually.

Moreover, although the above-mentioned second embodiment shows the example to be connected by using the universal links14and16, it is not limited to the universal link if it has a configuration that the adjoining light diffusion passive reflectors can be curved mutually. For example, it is easy to be natural also as a configuration to connect between the elements adjoining mutually with a rubber sheet etc. having elasticity, instead of the universal link.