CN1794055A - Light diffusing/collecting member and surface light source device using the same - Google Patents

Abstract

An object of the present invention is to provide a light-diffusing member and a surface light source device that can easily achieve a lightweight structure with a simple structure. The surface light source device (10) comprises: a flat light source (11); a substantially flat diffuser and light-condensing member (13) arranged above the light source, and the above-mentioned diffuser and light-condenser member (13) is successively composed of light-emitting diodes with a diffusion function from the light source side; Diffusion layer (24), low refractive index layer (25) and light concentrating layer (26) with light concentrating function are integrally constituted, and above-mentioned low refraction index layer (25) utilizes refractive index ratio diffusion layer (24) and light concentrating layer (26) Low material composition, thereby constituting the surface light source device (10).

Description

Diffusion and concentrating parts and surface light source device

technical field

The present invention relates to a surface light source device used for backlighting transmissive display devices such as liquid crystal panels, for example.

Background technique

Conventionally, a transmissive display device such as a liquid crystal panel uses a surface light source device to illuminate from the back in order to obtain a brighter screen display. Especially for color liquid crystal panels used in personal computers and liquid crystal televisions, since the aperture ratio of the driving circuit is restricted, and the light transmittance is lowered by color filters, it is necessary to perform backlighting using a surface light source device.

Generally, such surface light source devices for backlighting are classified into so-called side type and direct type according to the arrangement of light sources. In addition, in particular, surface light source devices for backlighting large display devices such as large televisions of 20 inches or more are often of the direct type that does not require a light guide plate and can be easily reduced in weight by forming a hollow structure.

Such a direct type surface light source device is configured as shown in FIG. 7, for example.

In FIG. 7 , the surface light source device 1 is composed of the following parts: at least one, four linear light sources 2 in the illustrated case; a reflective surface 3 arranged under each linear light source 2; Diffusion plate 4, diffusion sheet 5, and prism sheet 6 above surface 3.

The above-mentioned linear light source 2 can be constituted by, for example, cold-cathode tubes, etc., and is arranged in parallel with each other at equal intervals so as to irradiate light to the entire light-emitting surface A above.

The above-mentioned reflective surface 3 is constituted, for example, as a diffuse reflective surface realized by white spray coating or a foamed resin sheet, etc., and is arranged below each linear light source 2, so that the light emitted from the corresponding linear light source 2 to the bottom or side is generally in the direction of As an upward reflection in the outgoing direction.

The above-mentioned diffusion plate 4 is constituted by, for example, a light-transmitting plate material on which a light-diffusing pattern is formed on the surface.

The above-mentioned diffusion sheet 5 is made by adding and mixing a light diffusing agent to a resin as a base material, for example, by adding and mixing a light diffusing agent such as calcium carbonate and titanium oxide, and partially crosslinked polymer particles to a polycarbonate resin. Or insoluble propylene polymer elements, titanium oxide and silicon compounds.

In addition, the prism sheet 6 is formed, for example, by injection molding, 2P method, or compression molding of a transparent resin (eg, acrylic resin, polycarbonate, etc.) at least in the visible light region in order to have microprisms on the surface.

According to the surface light source device 1 configured in this way, when each linear light source 2 is turned on, the light emitted from each linear light source 2 is diffused by the upper diffusion plate 4 after being directly or reflected by the reflection surface 3, and then diffused by the diffusion sheet 5. , and is condensed by the prism sheet 6, and then emitted upward.

Thereby, various display devices (not shown), such as a liquid crystal panel, arranged above the light emitting surface A are backlit.

At this time, when the light emitted from each linear light source 2 passes through the diffuser plate 4 , the diffuser sheet 5 and the prism sheet 6 , it is diffused or condensed respectively, thereby obtaining a backlight with uniform brightness as a whole.

However, in the liquid crystal display device disclosed in Patent Document 1 with a backlight device, the backlight device is composed of a plurality of linear light sources arranged parallel to each other; ; a diffuser plate disposed above it; and an optical film with light diffusion or light concentrating functions.

According to this structure, each linear light source and the corresponding reflector are integrally formed, and constitute the structure which can be attached and detached by sliding in the longitudinal direction. Thereby, replacement|exchange of a linear light source can be performed easily.

Furthermore, Patent Document 2 discloses an illuminating device comprising: a plurality of linear light sources arranged parallel to each other; a reflector arranged below; a diffuser arranged above; and a diffuser arranged above. sheets and/or prism sheets.

According to this configuration, a gap is provided above the diffusion plate, or the diffusion sheet and/or the prism sheet are brought into close contact with the upper surface of the diffusion plate, and the light-transmitting sheet is brought into close contact with the lower surface of the diffusion plate. As a result, the upper and lower surfaces of the diffuser are in direct contact with the outside air or are sealed so that there is no difference in temperature and humidity between the upper and lower surfaces, so that the diffuser is not deformed into a concave or convex shape relative to the upper side. Therefore, it is possible to suppress occurrence of uneven brightness of the backlight illumination due to deformation of the diffuser plate.

Patent Document 1 Japanese Patent Application Laid-Open No. 11-002813

Patent Document 2 Japanese Patent Application Laid-Open No. 11-223812

However, in the conventional surface light source device 1 shown in FIG. 7, for example, in order to diffuse the light from the linear light source 2 and obtain uniform brightness, a diffusion plate 4 and a diffusion sheet 5 are required, and a prism sheet 6 is required to increase the brightness. .

Therefore, the diffuser plate 4, the diffuser sheet 5, and the prism sheet 6 are sequentially arranged above the linear light source 2, resulting in an increase in the number of parts, a complicated assembly process, and an increase in cost.

In addition, the above-mentioned diffusion plate 4 is generally made of a resin plate of about 2-3 mm. Due to the increase in the number of components, especially when used as a backlight for a large display device, the weight increases, which violates the light weight requirement of the display device itself.

On the other hand, in the backlight device for a liquid crystal display device of Patent Document 1 above, an optical sheet is disposed above the diffuser plate, and the optical sheet is simply stacked on the diffuser plate, which also increases the number of parts.

In addition, in the lighting device of the above-mentioned Patent Document 2, the diffusion sheet and/or the prism sheet are arranged above the diffusion plate, and these diffusion sheets and/or prism sheets are arranged at intervals above the diffusion plate, or in order not to contact the outside air. And in close contact, but not integrated with the diffuser plate.

Therefore, in the lighting devices of Patent Document 1 and Patent Document 2 as well, the number of parts increases and the assembly process becomes complicated, thereby increasing the cost and increasing the weight.

In addition, the purpose of arranging the diffuser sheet and/or prism sheet at intervals above the diffuser plate is to make the environmental conditions of the upper surface and the lower surface of the opposite diffuser plate the same, and prevent the above-mentioned diffuser plate from being deformed into a convex or convex shape due to temperature difference and humidity difference. Concave.

In addition, even if these optical films or diffusion sheets and/or prism sheets are pasted on the diffusion sheet, or the optical sheet of the double-layer structure composed of the diffusion layer and the prism layer is integrally formed using materials with approximately the same refractive index, The light-collecting function of the prism is also suppressed, however, as a result, the meaning given to the shape of the prism is reduced.

On the other hand, reducing the concentration of the diffusing agent contained in the diffusing layer can improve the light-collecting function, but the diffusing function decreases accordingly.

Contents of the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light-diffusing member and a surface light source device that can easily obtain a light-weight structure with a simple structure.

The above object is achieved by the first mode of the present invention, which is a substantially flat diffusing and concentrating member arranged above a flat light source and constituting a surface light source device, characterized in that the diffusing and concentrating member starts from the light source side A diffusion layer having a diffusion function, a low refractive index layer and a light concentrating layer having a light concentrating function are sequentially integrally formed, and the low refraction index layer is composed of a material having a lower refractive index than the diffusion layer and the light concentrating layer.

In this first aspect, the light incident on the diffusion layer from below can be reliably diffused by the diffusion layer, and since the low refractive index layer is arranged on the diffusion layer, the light incident on the low refractive index layer from above the diffusion layer can be diffused reliably. Due to the difference in refractive index, the light in the layer can be refracted in a diffusion direction in which the outgoing angle is larger than the incident angle, thereby fully exerting the diffusing function of the diffusing layer.

In addition, the light that passes through the low-refractive index layer and enters the light-concentrating layer also enters at a relatively large incident angle, so the light-concentrating function is also fully exerted.

Therefore, by integrating the diffusion layer and the light-condensing layer with the low-refractive-index layer interposed therebetween while maintaining the diffusion and light-concentrating functions of the conventional diffusion layer and the independent light-concentrating layer, they can be formed as one part. , so the number of parts is reduced, the assembly is simple, and the cost of parts and assembly costs are reduced.

Thus, the surface light source device can be constituted by a simple structure in which the diffusing and concentrating member is arranged on the light source, and the number of parts constituting the surface light source device is reduced, the assembly process becomes simple, the component cost and the assembly cost are reduced, and the surface light source device as a whole Can form a lightweight structure.

According to a second aspect of the present invention, in the diffusion and light-condensing member of the first aspect, the low refractive index layer has a refractive index lower than that of the substrate constituting the diffusion layer and the light-condensing layer. It consists of a medium that is transparent at least in the visible region.

In this second form, a low-refractive-index layer made of a low-refractive-index transparent medium, such as resin, glass, and air, is provided between the diffusion layer and the light-concentrating layer, thereby making it easy to form a three-layer structure for diffusing and concentrating light. .

According to a third aspect of the present invention, in the diffusion and concentration member of the second aspect, the low refractive index layer is an airtight hollow space defined between the diffusion layer and the concentration layer. department.

In the third mode, the low-refractive index layer is formed by the hollow portion defined between the diffusion layer and the light-concentrating layer, so that the three-layer structure of the light-diffusing and light-concentrating member can be formed with less material and at a lower cost.

The above object is achieved by the fourth aspect of the present invention, which is a substantially flat diffusing and concentrating member arranged above a flat light source and constituting a surface light source device, wherein the diffusing and concentrating member starts from the light source side A diffusion layer having a diffusion function and a light concentrating layer having a light concentrating function separated from the diffusion layer by a predetermined interval by a ridge layer are sequentially integrally formed.

In this fourth mode, since the light incident on the diffusion layer from below can be reliably diffused by the diffusion layer, and the air layer defined by the prism layer is arranged on the diffusion layer, the light incident from above the diffusion layer to the Since the refractive index of the air layer is lower than that of the diffusion layer, the light in the air layer can be refracted in a diffusion direction in which the outgoing angle is larger than the incident angle according to the difference in refractive index, thereby fully exerting the diffusion function of the diffusion layer.

Moreover, the light incident on the light concentrating layer through the air layer is also incident at a relatively large incident angle, so its light concentrating function is also fully exerted.

Therefore, by integrating the diffusion layer and the light-condensing layer with the ridge layer interposed therebetween while maintaining the diffusion function and the light-condensing function of the conventional diffusion layer and the independent light-collecting layer, they can be formed as one part, so The number of parts is reduced, the assembly is simple, and the cost of parts and assembly costs are reduced.

Thus, the surface light source device can be constructed by simply disposing the light-diffusing member on the light source, and the number of components constituting the surface light source device is reduced, the assembly process is simplified, and the component cost and assembly cost are reduced.

In addition, since the diffusing and concentrating member includes an air layer defined by prism layers, it is formed to have a hollow structure, which is significantly lighter than a conventional diffuser plate having the same thickness as a whole, thereby realizing a lightweight structure of the surface light source device as a whole.

According to a fifth aspect of the present invention, in the diffusion and light-condensing member of the fourth aspect, the ridge layer is formed integrally with the diffusion layer and the light-condensing layer.

In this fifth aspect, the diffusing layer, light concentrating layer, and ridge layer constituting the diffusing and concentrating member are formed integrally with each other, and thus can be formed by, for example, extrusion molding.

According to a sixth aspect of the present invention, the diffusion and light-concentrating member is characterized in that, in the above-mentioned fourth aspect, the diffusion and light-condensing member is characterized in that the prism layer and the diffusion layer are integrally formed, and an independent light-concentrating layer is pasted thereon. layer.

In the sixth aspect, the prism layer and the diffusion layer are integrally formed, and the independent light-concentrating layer is pasted thereon, so that the diffusion layer and the light-concentrating layer arranged at predetermined intervals are easily integrated.

According to a seventh aspect of the present invention, in the diffusing and focusing member of the first aspect, the diffusion layer is formed of a resin material in which a diffusing agent or a pigment is added and mixed with a base material.

In this seventh aspect, the substrate has a diffusion function by adding and mixing a diffusing agent or a pigment.

A light-diffusing member according to an eighth aspect of the present invention is characterized in that, in the light-diffusing member of any one of the first to seventh aspects, the light-condensing layer is made of a resin material that is transparent at least in the visible light region. Alternatively, it may be composed of a resin material mixed with an extremely low concentration of a diffusing agent or a pigment, and the upper surface and/or lower surface thereof may have an optically processed shape having a light-condensing function.

According to the ninth form of the present invention, the light-diffusing member of the present invention is characterized in that, in the above-mentioned light-diffusing member of the eighth form, the above-mentioned optically processed shape is a quadratic curve such as a triangle, a trapezoid, or a parabola, an ellipse arc, Or the cross-sectional shape of their combination is a prism shape obtained by sweeping in a direction perpendicular to the cross-section.

According to the tenth aspect of the present invention, the light-diffusing member of the eighth aspect is characterized in that, in the above-mentioned eighth aspect, the optically processed shape is a micro polygonal pyramid or an aspherical lens array.

According to the eleventh aspect of the present invention, in the diffuser and light-condensing member of the eighth aspect, the optically processed shape is formed by coating substantially spherical particles made of a transparent material such as resin or glass. And provided.

In the eighth to eleventh aspects, the upper surface and/or the lower surface of the transparent material or the resin material mixed with a very low concentration of diffusing agent or pigment has an optically processed shape, so as to have a light-collecting function. The processing shape is preferably a prismatic shape obtained by sweeping the cross-sectional shape of a triangle, trapezoid, or a quadratic curve such as a parabola or an elliptical arc, or a combination of them in a direction perpendicular to the cross-section, or a tiny polygonal cone, non- Spherical lens array, or a shape given by coating spherical particles made of transparent materials such as resin or glass.

The above object is achieved by the twelfth aspect of the present invention, which is a surface light source device, which is characterized in that it includes: a flat light source; any one of the aforementioned first to eleventh aspects arranged above the light source Diffuse spotlight parts.

In the twelfth aspect, the surface light source device is constituted by combining the above-mentioned diffusing and concentrating components with the light source, so the number of components is reduced, the assembly is easy, the component cost and assembly cost are reduced, and the overall weight is reduced, thereby A surface light source device suitable for backlighting of a large display device can be realized.

As described above, according to the present invention, the conventional diffusion plate and the optical components having the function of diffusing and concentrating light are integrated with each other, thus constituting a single component, so the cost of components and assembly costs are reduced, and it can be combined with the light source and the reflective surface. In the case of forming a surface light source device, it is possible to reduce component costs and assembly costs while maintaining the diffusion function and light collection function, and further realize weight reduction. Therefore, as a backlight lighting device for large display devices, the most suitable surface can be provided light source device.

Description of drawings

FIG. 1 is a schematic cross-sectional view showing the configuration of an embodiment of a surface light source device according to the present invention.

Fig. 2 is a schematic perspective view showing the appearance of the surface light source device of Fig. 1 .

Fig. 3 is a cross-sectional view of a diffuser and condensing member used in the surface light source device of Fig. 1 .

4 is a schematic cross-sectional view showing the structure of another embodiment of the surface light source device of the present invention.

Fig. 5 is a schematic perspective view showing the appearance of the surface light source device shown in Fig. 4 .

Fig. 6 is a cross-sectional view of a diffuser and condensing member used in the surface light source device of Fig. 4 .

7 is a schematic cross-sectional view showing an example of the structure of a conventional surface light source device.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6 .

In addition, the embodiments described below are preferred specific examples of the present invention, so various technically preferable limitations are made, but the scope of the present invention is not limited to these embodiments unless there is a description that specifically limits the present invention in the following description. .

[Example 1]

1 and 2 show the structure of an embodiment of the surface light source device of the present invention.

In FIGS. 1 and 2 , the surface light source device 10 is composed of the following parts: at least one, four linear light sources 11 in the illustrated case; a reflective surface 12 arranged under each linear light source 11; the linear light source 11 is arranged And the diffusing and concentrating member 13 above the reflective surface 12.

The above-mentioned linear light source 11 is constituted by, for example, cold-cathode tubes or the like, and is arranged parallel to each other at equal intervals in a flat shape so as to irradiate light to the entire upper light-emitting surface A.

The above-mentioned reflective surface 12 is constituted, for example, as a diffuse reflective surface formed by white spray coating or a foamed resin sheet, etc., and is disposed below each linear light source 11, so that the light emitted downward or sideways from the corresponding linear light source 11 is generally toward the As an upward reflection in the outgoing direction.

The above-mentioned diffusing and concentrating member 13 is formed into a three-layer structure shown in detail in FIG. 3 , and is composed of a diffusion layer 14 , a low refractive index layer 15 and a concentrating layer 16 in order from the bottom.

The above-mentioned diffusion layer 14 has a diffusion function, and is generally composed of a resin material in which a diffusion agent is added and mixed with a base material.

Specifically, the diffusion layer 14 is formed of, for example, a transparent resin such as polycarbonate resin as a base material, and a resin material in which fine particles such as cross-linked polymethacrylic acid are added and mixed.

The light collecting layer 16 is made of a transparent resin material at least in the visible light region, such as polycarbonate, and has an optically processed shape 16a on its upper surface and/or lower surface, which is the upper surface in the illustration.

The optical processing shape 16a is a prism shape obtained by sweeping the cross-sectional shape of a triangle, a trapezoid, or a quadratic curve such as a parabola or an elliptical arc, or a combination thereof in a direction perpendicular to the cross-section, or a tiny polygonal cone. , an aspherical lens array, or a shape formed by coating spherical particles made of transparent materials such as resin or glass.

On the other hand, the above-mentioned low refractive index layer 15 is composed of a medium having a refractive index lower than that of the above-mentioned diffusion layer 14 and light-concentrating layer 16, at least transparent in the visible light region, and preferably an airtight air layer. It is the airtight hollow part between the above-mentioned diffusion layer 14 and light concentrating layer 16 .

And, in the case of the figure, the diffusion and light-concentrating member 13 of this three-layer structure is defined as a hollow space sealed by the diffusion layer 14 and the light-concentration layer 16 by, for example, gas injection molding, two-color molding, or mold slide molding. The low-refractive index layer 15 in the lower part can be easily molded into one body.

The surface light source device 10 according to the embodiment of the present invention is structured as described above. When power is supplied to each linear light source 11 from the outside, each linear light source 11 is turned on, and the light emitted from each linear light source 11 is directly or driven. After being reflected by the reflective surface 12, it is incident on the upper diffusing and concentrating member 13 .

In addition, the light incident on the diffusing and concentrating member 13 is first diffused by the diffusing layer 14 , then exits from the diffusing layer 14 and enters the low refractive index layer 15 . At this time, the incidence from the diffusion layer 14 is incident on the low-refractive index layer 15 made of a medium with a lower refractive index, thus on the interface between the diffusion layer 14 and the low-refractive index layer 15, the outgoing angle is greater than the incident angle, so the diffusion layer 14's spread effect increased.

In addition, the light incident on the light-condensing layer 16 from the low-refractive-index layer 15 is condensed according to the optically processed shape 16 a of the light-condensing layer 16 , and then emitted upward from the upper surface of the light-condensing layer 16 .

Thereby, various display devices (not shown), such as a liquid crystal panel, arranged above the light emitting surface A are backlit.

At this time, the light emitted from each linear light source 11 is sufficiently diffused and condensed by the light-diffusing and concentrating member 13 , so that overall uniform and high-intensity backlighting can be obtained.

In this case, in order to diffuse and condense the light emitted from the linear light source 11, the diffusion and condensing member 13 as an integral part is used, so the number of parts constituting the surface light source device 10 is reduced, and the cost of the parts and the assembly cost are reduced. The cost is reduced, and the light-diffusing and concentrating member 13 and the surface light source device 10 are reduced in weight, thereby fully meeting the weight reduction requirements such as backlighting of a large liquid crystal panel or the like.

[Example 2]

4 and 5 show the structure of another embodiment of the surface light source device of the present invention.

In FIGS. 4 and 5 , the surface light source device 20 is composed of the following parts: at least one, four linear light sources 21 in the figure; a reflective surface 22 arranged under each linear light source 21; the linear light source 21 is arranged And the diffusing and concentrating member 23 above the reflective surface 22 .

The above-mentioned linear light source 21 is constituted by, for example, cold cathode tubes or the like, and is arranged parallel to each other at equal intervals in a flat shape so as to irradiate light to the entire upper light-emitting surface A.

The above-mentioned reflective surface 22 is constituted, for example, as a diffuse reflective surface formed by white spray coating or a foamed resin sheet, etc., and is disposed below each linear light source 21, so that the light emitted downward or sideways from the corresponding linear light source 21 is generally directed towards the As an upward reflection in the outgoing direction.

The above-mentioned diffusing and concentrating member 23 is formed into a three-layer structure shown in detail in FIG. 6 , and is composed of a diffusing layer 24 , a prism layer 25 and a concentrating layer 26 in order from the bottom.

The above-mentioned diffusion layer 24 has a diffusion function, and is generally composed of a resin material in which a diffusion agent is added and mixed with a base material.

Specifically, the diffusion layer 24 is formed of, for example, a transparent resin such as polycarbonate resin as a base material, and a resin material in which fine particles such as cross-linked polymethacrylic acid are added and mixed.

In addition, the light-condensing layer 26 is made of a transparent resin material at least in the visible light region, such as polycarbonate, and has an optically processed shape 26a on its upper surface and/or lower surface, which is the upper surface in the drawing.

The optical processing shape 26a is a prism shape obtained by sweeping the cross-sectional shape of a triangle, a trapezoid, or a quadratic curve such as a parabola or an elliptical arc, or a combination thereof in a direction perpendicular to the cross-section, or a tiny polygonal cone. , an aspherical lens array, or a shape formed by coating spherical particles made of transparent materials such as resin or glass.

On the other hand, the ridge layer 25 is composed of a plurality of ridges 25a dispersed and arranged appropriately, the diffusion layer 14 and the light concentrating layer 16 are separated from each other by a predetermined interval, and an air layer 27 is defined therebetween.

Here, each rib 25a is formed of a plate-shaped, cone-shaped, or column-shaped resin material integrated with the above-mentioned diffusion layer 24 and/or light-concentrating layer 26 .

In addition, such a three-layer diffuser and light-condensing member 23 is generally formed by integrally molding the ridge layer 25, the diffusion layer 24, and the light-condensing layer 26 by extrusion molding or the like, for example.

On the other hand, after molding the ridge layer 25 integrally with only the diffusion layer 24 by extrusion molding or the like, it may be bonded to the independent light-concentrating layer 26 molded by ultraviolet curing or the like.

In addition, after the ridge layer 25 is integrally formed between the diffusion layer 24 and the transparent layer (not shown) in which a diffusion agent or a pigment is added and mixed at a very low concentration by extrusion molding or the like, the ultraviolet curing method or the like can be used for pasting. Formed independent light concentrating layer 26 and the above-mentioned transparent layer. In this case, the light-gathering layer 26 is firmly fixed to the transparent layer, thereby improving mounting strength.

The surface light source device 20 according to the embodiment of the present invention is structured as described above. When power is supplied to each linear light source 21 from the outside, each linear light source 21 lights up, and the light emitted from each linear light source 21 is directly or After being reflected by the reflective surface 22, it is incident on the upper diffusing and concentrating member 23 .

And, the light incident on the diffusing and concentrating member 23 is first diffused by the diffusing layer 24 , then exits from the diffusing layer 24 , and then enters the air layer 27 defined by each rib 25 a of the rib layer 25 .

At this time, the incidence from the diffusion layer 24 is incident on the air layer 27 made of a medium with a lower refractive index, so that at the interface between the diffusion layer 24 and the air layer 27, the outgoing angle is greater than the incident angle, so the diffusion effect of the diffusion layer 24 increase.

In addition, the light incident on the light concentrating layer 26 from the air layer 27 is condensed by the optically processed shape 26 a of the light concentrating layer 26 , and then emitted upward from the upper surface of the light concentrating layer 26 .

Thereby, various display devices (not shown), such as a liquid crystal panel, arranged above the light emitting surface A are backlit.

At this time, the light emitted from each linear light source 21 is sufficiently diffused and condensed by the light-diffusing and condensing member 23 , so that overall uniform and high-intensity backlighting can be obtained.

In this case, in order to diffuse and condense the light emitted from each linear light source 21, the diffusion and condensing member 23 as an integral part is used, so the number of parts constituting the surface light source device 20 is reduced, and the cost and cost of the parts are reduced. The assembly cost is reduced, and the light-diffusing and concentrating member 23 and the surface light source device 20 are reduced in weight, thereby fully meeting the requirements for reducing the weight of, for example, backlighting of a large liquid crystal panel or the like.

[industrial availability]

In the above-mentioned embodiments, the light-concentrating layer of the diffuse light-concentrating member has an optically processed shape only on its upper surface, but it is not limited thereto, and may have an optically processed shape only on the lower surface or on both the upper and lower surfaces.

Furthermore, in the above-mentioned embodiment, the low-refractive index layer is formed of air as the hollow portion, but it is not limited thereto, and may be formed of other appropriate media including the same gas, liquid, and solid as a matter of course.

Thus, according to the present invention, it is possible to provide a light-diffusing member and a surface light source device that can easily realize a lightweight structure with a simple structure.

Furthermore, the surface light source device of the present invention can be used as an illumination device such as a backlight of a liquid crystal panel, a light-transmitting signboard printed on a transparent film, or the like, or a local lighting on a desk.

Claims (12)

1. A top that is configured in the light source of flat, configuration, constitute the diffusion optically focused parts of the general planar of planar light source device, it is characterized in that,

   Above-mentioned diffusion optically focused parts begin successively to be made of integratedly the diffusion layer with diffusion function, low-index layer and light collecting layer with light-focusing function from light source side,

   Above-mentioned low-index layer is made of refractive index ratio diffusion layer and the low material of light collecting layer.
2. 2. diffusion optically focused parts according to claim 1 is characterized in that, above-mentioned low-index layer by refractive index ratio constitute the base material of above-mentioned diffusion layer and light collecting layer low, be that transparent medium constitutes in the visible region at least.
3. 3. diffusion optically focused parts according to claim 2 is characterized in that, above-mentioned low-index layer is the airtight hollow bulb that limits between above-mentioned diffusion layer and light collecting layer.
4. A top that is configured in the light source of flat, configuration, constitute the diffusion optically focused parts of the general planar of planar light source device, it is characterized in that,

   Above-mentioned diffusion optically focused parts begin to be made of integratedly the light collecting layer with light-focusing function that the rib layer separates predetermined space by the diffusion layer with diffusion function with respect to this diffusion layer successively from light source side.
5. 5. diffusion optically focused parts according to claim 4 is characterized in that above-mentioned rib layer and above-mentioned diffusion layer and light collecting layer constitute one.
6. 6. diffusion optically focused parts according to claim 4 is characterized in that above-mentioned rib layer and above-mentioned diffusion layer constitute one, have pasted independent light collecting layer thereon.
7. 7. according to each described diffusion optically focused parts in the claim 1～6, it is characterized in that above-mentioned diffusion layer constitutes by adding the resin material that has mixed diffusant or pigment in the base material.
8. 8. according to any described diffusion optically focused parts in the claim 1～7, it is characterized in that above-mentioned light collecting layer is by being transparent resin material at least in the visible region or adding the resin material that has mixed diffusant or pigment with extremely low concentration and constitute,

   Surface and/or lower surface have the optics machining shape that possesses light-focusing function thereon.
9. 9. diffusion optically focused parts according to claim 8, it is characterized in that, above-mentioned optics machining shape be the section configuration of the quafric curve of triangle, trapezoidal or para-curve, elliptic arc etc. or their combination with the direction of cross section perpendicular on scan and the prism shape that obtains.
10. 10. diffusion optically focused parts according to claim 8 is characterized in that, above-mentioned optics machining shape is the lens arra of small polygonal awl, aspherical shape.
11. 11. diffusion optically focused parts according to claim 8 is characterized in that, above-mentioned optics machining shape is to be given by the roughly spheroidal particle that transparent materials such as resin or glass constitute by coating.
12. 12. a planar light source device is characterized in that, comprising: the light source of flat, configuration; Be configured in any described diffusion optically focused parts in the claim 1～11 of above-mentioned light source top.

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