JP3936871B2 - Light guide block - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention provides a light guide block for emitting light introduced from a light incident end face from a light emitting end face opposed to the light incident end face.ToIn particular, it is suitable for the case where light is emitted uniformly from the entire area of the light emitting end face having a large area.
[0002]
[Prior art]
As a flat illumination device used as a light source of a transmissive liquid crystal display device, various forms are used according to the display area of the liquid crystal display device. However, in order to reduce power consumption, a fluorescent lamp or LED array is used as a light source, and the flat illumination device is made flat in order to make the flat illumination device compact in the depth direction and at the same time obtain uniform light distribution characteristics on the liquid crystal display surface. In most cases, a light guide plate having a shape is used, and light from a light source incident from the side end face of the light guide plate is uniformly emitted from the surface of the light guide plate. On the front and back surfaces of such a light guide plate, minute irregularities for changing the propagation characteristics of light propagating in the light guide plate and the light emission direction from the surface of the light guide plate are formed in a predetermined pattern, Thereby, substantially uniform light can be emitted from the entire surface of the light guide plate.
[0003]
With the advancement of liquid crystal technology, liquid crystal display devices having a very large display area can be manufactured. In such a large transmissive liquid crystal display device, even if fluorescent lamps are arranged on all side end surfaces of the light guide plate, the amount of light at the center of the liquid crystal display surface is insufficient, and is uniform over the entire display surface. It is difficult to have a good light distribution characteristic. For this reason, as a flat illumination device used for a transmissive liquid crystal display device with a very large display area, a light source such as a fluorescent lamp is arranged on the back surface of the liquid crystal display device through a diffuser plate, and this is covered with a reflector. Things have become commonplace.
[0004]
[Problems to be solved by the invention]
A large light guide plate with minute irregularities to change the propagation characteristics of light propagating inside and the light emission direction from the surface in a predetermined pattern is fundamentally impossible to roll forming, so it is manufactured by injection molding However, as the area of the light guide plate is increased, the molding pressure must be increased, and an extremely large injection molding apparatus is required, resulting in a disadvantage that the equipment cost increases.
[0005]
In the case of a structure in which a light source is arranged between the diffuser plate and the reflector, it is necessary to increase the distance from the diffuser plate to the light source to some extent in order to have uniform light distribution characteristics over the entire area of the diffuser plate. The light from the light propagates in the air to the diffuser plate. For this reason, in combination with the use of a diffuser plate, the attenuation of light is large, and even if uniform light distribution characteristics are obtained over the entire area of the diffuser plate, in order to obtain sufficient illuminance It is necessary to use a light source with high power consumption. Conversely, when the light source is arranged close to the diffuser plate, the intensity of the light emitted from the diffuser plate can be secured to some extent, but the uniform light distribution characteristics over the entire area of the diffuser plate. It is virtually impossible to have.
[0006]
OBJECT OF THE INVENTION
  An object of the present invention is a low power consumption flat illumination device capable of obtaining uniform light distribution characteristics even for a transmissive liquid crystal display device having a large display area.And a light guide block that can realize a low-power flat illumination device with uniform light distribution characteristics that can change the illumination area arbitrarilyIs to provide.
[0009]
[Means for Solving the Problems]
  The first aspect of the present invention is:Formed with cylindrical concave lens surface,Light is incidentSlenderA light incident end face portion, located on the opposite side of the light incident end face portion and having a larger area than the light incident end face portion, a light emitting end face portion from which light is emitted, and randomly formed on the light emitting end face portion A plurality of light deflecting directions of light emitted from the light emitting end face portions.Light ofPositioned between the deflection element and the light incident end face and the light exit end faceIncluding a pair of inclined surfacesFour side end surfaces,SaidA pair ofInclined surfaceFormed in a protruding stateA top part extending in parallel with the light emitting end face part, a first slope part facing the light incident end face part side from the top part, and a second slope part opposite to the first slope part,Multiple deflectors that deflect the direction of light travelPrism bodyWithTheIt is in the light guide block characterized by this.
[0010]
  In the present invention, light that has entered the light guide block from the light incident end face portion propagates in the light guide block toward the light exit end face portion while repeating total reflection at the side end face portion. In the middle, formed on the side end facePrism bodyThe direction of propagation of some light is deflected and diffused by theLightLight whose emission direction is controlled by the deflecting element is emitted almost uniformly over the entire area of the emission end face.
[0011]
  The second aspect of the present invention is:A light incident end face part where light is incident, a light emitting end face part which is located on the opposite side of the light incident end face part and has a larger area than the light incident end face part, and from which the light is emitted, and the light emitting end face part A plurality of light deflection elements that are randomly formed to deflect the light emission direction from the light emission end face part, and are positioned between the light incident end face part and the light emission end face part, and a pair of inclined surfaces Including four side end surface portions, a top portion formed in a protruding state on the pair of inclined surfaces, and extending parallel to the light emitting end surface portion, and a first inclined surface facing the light incident end surface portion side with the top portion as a boundary And a plurality of prism bodies for deflecting the traveling direction of light, respectively, and an inclination angle of the pair of inclined surfaces with respect to the light emitting end surface portion is the light emitting end surface portion The side is set largerIt is characterized byLight guide blockIt is in.
[0013]
  The third aspect of the present invention is:A light incident end face part where light is incident, a light emitting end face part which is located on the opposite side of the light incident end face part and has a larger area than the light incident end face part, and from which the light is emitted, and the light emitting end face part A plurality of light deflection elements that are randomly formed to deflect the light emission direction from the light emission end face part, and are positioned between the light incident end face part and the light emission end face part, and a pair of inclined surfaces Including four side end surface portions, a top portion formed in a protruding state on the pair of inclined surfaces, and extending parallel to the light emitting end surface portion, and a first inclined surface facing the light incident end surface portion side with the top portion as a boundary And a plurality of prism bodies that respectively deflect light traveling directions, and an angle formed by the light emitting end face portion and the second slope portion of the prism body is In the opposite direction of the light incident end face and the light exit end face It is set larger the light emission end surface portion side IIt is characterized byLight guide blockIt is in.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The light guide block according to the first embodiment of the present invention can be molded into optically transparent PMMA, PC, zeonor (trade name: Nippon Zeon Co., Ltd.), Arton (trade name: JSR Corporation), etc. in addition to optical glass. It can be manufactured using a simple resin.
[0016]
  In the light guide block according to the first aspect of the present invention,The light deflection element includes an isosceles triangular opening whose base is parallel to the central axis of curvature of the concave lens surface of the light incident end face, and includes a pair of conical surfaces perpendicular to the light exit end face and the base It may be a triangular pyramid-shaped recess having an inclined cone surface. In this case, it is preferable that the light deflection element is formed so as to have a larger occupation ratio toward the center of the light emitting end face.
  In the light guide block according to the second aspect of the present invention,The light incident end face portion may be a convex surface or a concave surface other than a flat surface, and may be formed of, for example, a conical surface, a truncated cone surface, a lens surface or a lenticular surface thereof, or a lenticular prism surface. When the light incident end face portion is composed of a lenticular lens surface or a lenticular prism surface, it is effective to change the characteristics and distribution of individual optical elements between the central portion and the outer peripheral edge portion of the incident end face portion. A surface is preferable in terms of ease of manufacture and effects.
[0017]
lightThe deflecting element may be convex or concave with respect to the light emitting end face, and may be a part of a spherical surface, a circular or polygonal columnar shape, or a conical shape (prism shape). Occupied per unit area of the light exit endLightIt is preferable that the ratio of the area of the deflecting element is set to be larger as the distance from the light incident end face portion is longer.
[0019]
  The interval between the prism bodies along the opposing direction of the light incident end face portion and the light exit end face portion is set closer to the light exit end face portion side, or the height of the top of the prism body is set to the light incident end face portion and the light exit end face portion. The light exit end face side is set higher along the facing direction ofRisuIt is preferable.
[0020]
  It may further include at least a pair of connection end surface portions that are formed between the light emitting end surface portion and the side end surface portions and are respectively perpendicular to the light emitting end surface portion. In this case, one of the pair of connection end surface portions has a locking projection, and the other has a locking recess having a shape corresponding to the locking projection.good.
[0021]
A light reflecting layer formed on the surface of the side end surface portion can be further provided. In this case, the light reflecting layer has a metal or a white inorganic substance, and can be formed by vapor deposition, sputtering, coating, or adhesion.
[0022]
【Example】
  According to the inventionLight guide blockFlat lighting deviceIncorporated inExamples will be described in detail with reference to FIG. 1 to FIG. 8, but the present invention is not limited to these examples, and these may be further combined or may be described in the claims of this specification. Any changes and modifications encompassed by the inventive concept are possible and can naturally be applied to any other technique belonging to the spirit of the present invention.
[0023]
  In the first embodimentFlat lighting deviceOutsideThe view is shown in FIG. 1 in an exploded state, and the cross-sectional structure is shown in FIG. That is, the planar illumination device in the present embodiment is a pair of light guide blocks 11 each having a substantially isosceles triangular prism shape, a frame body 12 surrounding the outer peripheral edge of the light guide block 11, and the frame body 12. And a pair of casings 13 in which the light guide blocks 11 are respectively housed, and a pair of fluorescent lamps 14 that are housed in the casings 13 and are connected to a power source (not shown) as a light source of the present invention. Yes.
[0024]
The side shape of the light guide block 11 in the present embodiment is shown in FIG. 3, and an arrow IV part in FIG. 2 is extracted and enlarged and shown in FIG. That is, the light guide block 11 in this embodiment is formed of an optically transparent acrylic resin (PMMA) having a refractive index of about 1.4 to 1.7, and light from the fluorescent lamp 14 that is a light source is incident thereon. An elongated light incident end face portion 15, a rectangular light emitting end face portion 16 which is located on the opposite side of the light incident end face portion 15 and has a larger area than the light incident end face portion 15 and emits light, and a light incident 1st and 2nd side end surface parts 17 and 18 located between the end surface part 15 and the light emission end surface part 16, and between the light emission end surface part 16 and the 1st side end surface part 17, light emission And a pair of connection end surface portions 19 each perpendicular to the end surface portion 16.
[0025]
The elongated light incident end face 15 of the present embodiment facing the fluorescent lamp 14 and having a length substantially equal to the fluorescent lamp 14 has a cylindrical concave lens surface whose center axis of curvature (not shown) is parallel to the longitudinal direction of the fluorescent lamp 14. The light entering the light guide block 11 from here is taken into consideration in a plane perpendicular to the central axis of curvature of the cylindrical concave lens surface.
[0026]
The pair of first side end surface portions 17 are formed by a pair of inclined surfaces having a plane that passes through the central axis of curvature of the cylindrical concave lens surface and is perpendicular to the light emitting end surface portion 16 as symmetry planes. The end surface portion 18 is perpendicular to the central axis of curvature of the cylindrical concave lens surface.
[0027]
When the light incident end face portion 15 is formed as a flat surface, the light entering the light guide block 11 from here becomes the refractive index of the material constituting the light guide block 11 in a plane parallel to the second side end face portion 18. The incident critical angle depends on the angle, that is, it does not physically diffuse beyond the total reflection angle, so that the opening angle γ of the pair of first side end face portions 17 is larger than the total reflection angle of the material constituting the light guide block 11 In particular, when the distance from the light emitting end face portion 16 to the fluorescent lamp 14 that is a light source is set short to reduce the thickness of the flat illumination device, the opening angle γ of the pair of first side end face portions 17 is guided to the light guide block. 11 needs to be larger than the total reflection angle of the material constituting 11. In such a case, the light incident end face portion 15 is formed on the cylindrical concave lens surface as described above, thereby guiding the light incident into the light guide block 11 according to the opening angle γ of the pair of first side end face portions 17. It becomes possible to diffuse the entire area of the optical block 11.
[0028]
On one of the pair of connection end surface portions 19 extending in parallel with the central axis of curvature of the cylindrical concave lens surface, a plurality of locking convex portions 20 having a truncated cone shape are spaced apart along the longitudinal direction of the connection end surface portion 19. (Two in the illustrated example) are formed, and the other connecting end surface portion 19 has locking concave portions 21 having shapes corresponding to these locking convex portions 20 spaced apart along the longitudinal direction of the connecting end surface portion 19. A plurality (two in the illustrated example) are formed. The positions of the locking projections 20 and the locking recesses 21 formed on each connection end surface portion 19 are such that the locking projections 20 formed on one connection end surface portion 19 of the plurality of light guide blocks 11 are guided to the other light guide. When fitted into a locking recess 21 formed in the other connection end surface portion 19 of the block 11, the connection end surface portions 19 of these two light guide blocks 11 are completely overlapped, and light emission of the two light guide blocks 11 is performed. The end face portion 16 is set to be completely on the same plane without a step.
[0029]
  The light exit end face portion 16 has a plurality of deflecting directions of light emitted from the light exit end face portion 16.Light ofThe deflection elements 22 are randomly formed, and in this embodimentLightThe deflection element 22 has a convex spherical shape having a radius of about several tens of micrometers formed by a part of a spherical surface, and protrudes from the surface of the light emitting end face 16 by about several micrometers. thisLightThe dimensional shape, distribution, and the like of the deflection element 22 are the diffusion angle, brightness, and brightness of the light emitted from the light emitting end face portion 16.Is lightAppropriately set so as to be almost uniform over the entire area due to the presence of the deflection element 22. lightThe deflection element 22 may be concave with respect to the light emitting end face portion 16 as long as it can achieve such an object, and may have a circular or polygonal columnar shape or a conical shape. Occupied per unit area of the light emitting end face 16LightThe occupancy ratio of the deflecting element 22 increases as the distance from the light emitting end surface portion 16 passing through the central axis of curvature of the cylindrical concave lens surface increases, that is, as the linear distance from the light incident end surface portion 15 increases. As shown, the distribution basically shown in FIG. 5 is provided.
[0030]
  The first side end face portion 17 has a plurality of light deflecting directions.Prism body23 is formed. thesePrism body23Also lightSimilar to the deflection element 22, the diffusion angle, brightness, and brightness of the light finally emitted from the light emitting end face portion 16 are reduced.Prism body23 is appropriately set so as to be almost uniform over the entire area. In this examplePrism body23 has a top 24 extending in parallel with the light emitting end face 16, a first slope 25 facing the light incident end face 15 with the top 24 as a boundary, and a second slope 26 on the opposite side. YouTheIn the present embodiment, the interval P between the prism bodies along the facing direction of the light incident end face 15 and the light exit end face 16 is set to be narrower toward the light exit end face 16 side. like thisPrism bodyIt is also effective to form 23 on the second side end face portion 18.
[0031]
The height of the apex 24 of the prism body is set so that the light incident end face 15 and the light exit end face 16 have a uniform diffusion angle, brightness, and brightness over the entire region. Of the light emitting end face 16 and the angle θ formed by the light emitting end face 16 and the second inclined surface 26 of the prism body is set to the light incident end face 15 and the light emitting end face 16. The light emission end face 16 side may be set to be larger along the facing direction.
[0032]
  Therefore,Optical deflection element 22andPrism bodyBy appropriately adjusting the dimensional shape, distribution, and the like of 23, it is possible to diffuse light emitted from the light emitting end face portion 16 only in a desired direction, and to arbitrarily set the luminance distribution and brightness.
[0033]
In the present embodiment, the pair of first side end surface portions 17 are each formed as a flat surface. However, the opening angle γ of the pair of first side end surface portions 17 decreases continuously or stepwise toward the light emitting end surface portion 16 side. You may make it set so that it may become. That is, in the case of the light guide block 11 in which the opening angle γ of the pair of first side end surface portions 17 is set to be larger than the maximum refraction angle of incident light, the light amount and luminance emitted from the central portion of the light emitting end surface portion 16 are the first. It tends to be larger than the amount of light and luminance emitted from both side edges of the light emitting end face portion 16 adjacent to the side end face portion 17. For this reason, the light emission end face part 16 is relatively increased in light quantity and luminance emitted from both side edges of the light emission end face part 16 so that the light emission end face part 16 has a uniform light quantity and luminance over the entire area. It is effective to reduce the opening angle γ of the first side end face portion 17 close to the side and totally reflect the incident light incident on the light guide block 11 here. This is because the angle θ formed by the light emitting end face portion 16 and the second inclined surface portion 26 of the prism body is set to be larger toward the light emitting end face portion 16 side along the opposing direction of the light incident end face portion 15 and the light emitting end face portion 16. It is the same as that.
[0034]
The casing 13 covers the reflector 27 for efficiently reflecting the light emitted from the fluorescent lamp 14 to the light incident end face portion 15 of the light guide block 11, and the first and second side end face portions 17 and 18 of the light guide block 11. The inner peripheral surface of the light reflection cover 28 is subjected to a treatment such as metal plating or white coating so that light leaked from the light guide block 11 is incident on the light guide block 11 again. The light reflecting cover 28 in this embodiment surrounds the periphery of the light incident end face 15 of the light guide block 11 that is connected to each other and is subjected to the same reflection treatment as the inner peripheral surface of the light reflecting cover 28. The body 12 is integrally joined, and the frame body 12 has a width dimension substantially corresponding to the width of the connection end surface portion 19. The frame body 12 is formed with a positioning recess 29 and a positioning protrusion 30 that are locked to the locking protrusion 20 and the locking recess 21 of the connection end surface 19 that are not involved in the connection of the light guide block 11, respectively. Thus, the light guide block 11 can be accurately positioned with respect to the frame 12. The frame body 12 and the light reflection cover 28 adopt a fitting structure in this embodiment so that light does not leak to the outside from these coupling portions, and these are integrally joined by an adhesive (not shown) or the like. The
[0035]
  Therefore, the light emitted from the fluorescent lamp 14 enters the light guide block 11 from the light incident end face portion 15 by the reflector 27. The angle of the incident angle more than the incident critical angle is obtained by the action of the cylindrical concave lens surface of the light incident end face portion 15. And propagates in the light guide block 11 toward the light emitting end face 16 side. The light leaked to the outside from the first and second side end surface portions 17 and 18 and the connection end surface portion 19 is incident on the light guide block 11 again by the inner surface treatment of the light reflecting cover 28 and the frame body 12, and finally All the light exits from the light exit end face 16 of the light guide block 11. In this case, the diffusion angle, brightness, and brightness of the light emitted from the light emitting end face portion 16 arePrism body23 andLightDue to the presence of the deflecting element 22, it is almost uniform over its entire area.
[0036]
In the embodiment described above, the pair of second side end face portions 18 is set perpendicular to the central axis of curvature of the cylindrical concave lens surface. However, when a point light source such as an LED or a light bulb is employed as the light source, The second side end face portion 18 can also be inclined in the same manner as the first side end face portion 17 so that the light guide block 11 can be formed in a frustum shape as a whole. In this case, a connection end surface portion similar to the connection end surface portion 19 described above is also formed between the light emitting end surface portion 16 and the second side end surface portion 18 so that the light guide block 11 can be connected in two directions. It is also possible to make it. Thus, when the side end surface parts 17 and 18 are conical surfaces, the light from the point light source can be efficiently introduced into the light guide block 11.
[0038]
  In the embodiment described above, the planar illumination device is configured by combining a plurality of light guide blocks 11 in order to increase the illumination area, but it is also possible to configure the planar illumination device using only a single light guide block 11. It is. like thisNapeiraThe external appearance of another embodiment of the surface lighting device is shown in an exploded state in FIG. 6, and the planar shape of the VII portion is shown in FIG.LightAlthough the appearance of the deflection element 22 is shown in an enlarged manner in FIG. 8, elements having the same functions as those of the previous embodiment are designated by the same reference numerals, and redundant description is omitted.
[0039]
  That is, the opening angle γ of the pair of first side end surface portions 17 in the present embodiment is set to be larger than the opening angle of the pair of first side end surface portions 17 in the previous embodiment. In this case, the light exiting from the light exit end face portion 16 as it is without being totally reflected tends to increase. Therefore, the function of totally reflecting the light in the propagation direction that is emitted from the light emitting end face portion 16 as it is without being totally reflected in the light guide block 11 to the connection end face portion 19 or the first side end face portion 17 side.The lightThe deflection element 22 is provided so that the diffusion angle, brightness, and brightness of the light emitted from the light emitting end face portion 16 are made uniform. In this exampleLightThe deflecting element 22 is in a state in which a plurality of types are mixed, and in addition to a convex sphere having a radius of about several tens of micrometers formed by a part of a spherical surface as in the previous embodiment, the base 31 Has an isosceles triangular opening parallel to the central axis of curvature of the cylindrical concave lens surface, a pair of conical surfaces 32 perpendicular to the light emitting end surface portion 16, and an inclination in which the upper edge is the above-described base 31. A triangular pyramid-shaped recess having a conical surface 33 is provided. It is formed by this triangular pyramid-shaped recess.LightThe light in the propagation direction in which the inclined conical surface 33 of the deflecting element 22 is not totally reflected in the light guide block 11 and is emitted as it is from the light emitting end surface portion 16 is totally transmitted to the connection end surface portion 19 and the first side end surface portion 17 side. Has the function of reflecting. Formed by triangular pyramid recessesLightThe deflecting elements 22 are randomly formed so as to have a larger occupation ratio mainly toward the central portion side of the light emitting end face portion 16 of the light guide block 11 and have a convex spherical shape.LightThe deflecting elements 22 are randomly formed mainly so as to have a larger occupation ratio toward the connection end face 19 side of the light emitting end face portion 16.
[0040]
In the present embodiment, connection end surface portions 19 and 34 are formed on the entire circumference of the light guide block 11, and the elongated locking projection 20 and the locking recess 21 extending along the long side of the light emitting end surface portion 16. And a pair of flat connection end surface portions 34 extending along the short side of the light emitting end surface portion 16. You may make it form the latching convex part 20 and the latching recessed part 21 also in a pair of flat connection end surface part 34. FIG. In this embodiment, since the fluorescent lamp 14 serving as the light source has a length shorter than the length of the long side of the light emitting end surface portion 16, the pair of second side end surface portions 18 are replaced with the pair of first end surfaces. As in the case of the side end surface portion 17, the light incident end surface portion 15 is made to correspond to the length of the fluorescent lamp 14 serving as a light source. Therefore, the light guide block 11 in this embodiment has a substantially truncated pyramid shape.
[0041]
In the two embodiments described above, when a light reflecting layer containing a white inorganic substance such as metal or titanium oxide is formed on the surfaces of the first and second side end face portions 17 and 18 of the light guide block 11. Can eliminate light leakage from the first and second side end surface portions 17 and 18 to the outside of the light guide block 11, so that the light emitting end surface portion 16 can be suppressed. Thus, light can be emitted efficiently.
[0042]
【The invention's effect】
  Light guide block of the present inventionThe first form ofaccording to,Formed with cylindrical concave lens surface,Light is incidentSlenderA light incident end face portion, located on the opposite side of the light incident end face portion and having a larger area than the light incident end face portion, a light emitting end face portion from which light is emitted, and randomly formed on the light emitting end face portion A plurality of light deflecting directions of light emitted from the light emitting end face portions.Light ofPositioned between the deflection element and the light incident end face and light exit end faceIncluding a pair of inclined surfacesFour side end surfaces,A pair of inclined surfacesFormed in a protruding stateA top part extending in parallel with the light emitting end face part, a first slope part facing the light incident end face part side with the top part as a boundary, and a second slope part opposite to the first slope part,Multiple deflectors that deflect the direction of light travelPrism bodyAnd ingredientsYeahTherefore, while the light that has entered the light guide block from the light incident end face portion propagates through the light guide block toward the light exit end face portion.Prism bodyIs efficiently diffused byLightThe deflecting element can emit light with a substantially uniform light amount from the entire area of the light emitting end face.Further, the light that has entered the light guide block from the light incident end face can be efficiently diffused toward the light exit end face. Furthermore, a long light guide block having a polygonal column shape can be continuously manufactured by extrusion molding, pultrusion molding, or the like in addition to injection molding, and light from a linear light source is efficiently diffused into the light guide block. be able to.
[0043]
  According to the second form of the light guide block of the present invention, the light incident end face part on which light is incident, the light incident end face part located on the opposite side of the light incident end face part, and having a larger area than the light incident end face part, , A plurality of light deflection elements that are randomly formed on the light emission end surface and deflect the light emission direction from the light emission end surface, respectively, a light incident end surface, and a light emission end surface Four side end surface portions including a pair of inclined surfaces, a top portion formed in a protruding state on the pair of inclined surfaces, and extending in parallel with the light emitting end surface portion, and light from the top portion as a boundary. A plurality of prism bodies each having a first inclined surface portion facing the incident end surface portion side and a second inclined surface portion on the opposite side and deflecting the traveling direction of the light, and a pair of inclined surfaces inclined with respect to the light emitting end surface portion The angle is set larger toward the light emitting end face Since the proportion of the light propagating in the light guide block that is totally reflected toward the light exit end face portion can be increased as it approaches the light exit end face portion side, On the other hand, the amount of light emitted from the outer peripheral edge can be relatively increased, and a more uniform amount of light can be emitted over the entire area of the light emitting end face.
  According to the third embodiment of the light guide block of the present invention, the light incident end surface portion on which light is incident, and the light incident end surface portion is located on the opposite side of the light incident end surface portion and has a larger area than the light incident end surface portion. , A plurality of light deflection elements that are randomly formed on the light emission end surface and deflect the light emission direction from the light emission end surface, respectively, a light incident end surface, and a light emission end surface Four side end surface portions including a pair of inclined surfaces, a top portion formed in a protruding state on the pair of inclined surfaces, and extending in parallel with the light emitting end surface portion, and light from the top portion as a boundary. A first inclined surface portion facing the incident end surface portion side and a second inclined surface portion on the opposite side; and a plurality of prism bodies for deflecting the light traveling directions, respectively, and the light emitting end surface portion and the second inclined surface of the prism body. The angle formed by the part is the opposite of the light incident end face and the light exit end face Since the ratio of breaking the total reflection condition of the light propagating in the light guide block increases as it approaches the light exit end face side, the light exit end face part increases. The amount of light emitted from the outer peripheral edge portion can be relatively increased with respect to the central portion of the light source, so that a more uniform amount of light can be emitted from the entire area of the light emitting end face portion.
[0044]
  Occupied per unit area of the light exit endLightWhen the ratio of the area of the deflection element is set to increase as the distance from the light incident end face increases, the light totally reflected at the light exit end faceIs lightSince there exists a tendency to radiate | emit from a light-projection end surface part by presence of a deflection | deviation element, the light of a more uniform light quantity can be radiate | emitted over the whole region of a light-projection end surface part.
[0045]
lightThe interval between the prism bodies along the opposing direction of the incident end face part and the light emitting end face part is set to be narrower toward the light emitting end face part side, or the height of the top of the prism body is set between the light incident end face part and the light emitting end face part. Set the light exit end face side higher along the facing direction.WhereIn this case, since the ratio of breaking the total reflection condition of the light propagating in the light guide block increases as it approaches the light emitting end face, the light from the outer peripheral edge is more than the central part of the light emitting end face. The amount of emission can be relatively increased, and a more uniform amount of light can be emitted from the entire area of the light emission end face.
[0046]
  In the case of further comprising at least a pair of connecting end surface portions formed between the light emitting end surface portion and the side end surface portions and perpendicular to the light emitting end surface portions, a plurality of light guide blocks are connected to these. It becomes possible to connect together via an end surface part, and the light guide block unit with arbitrary illumination areas can be comprised. In particular, when one of the pair of connection end surface portions has a locking projection and the other has a locking recess having a shape corresponding to the locking projection, the pair of light guide blocks coupled together Alignment can be performed easily and accurately.
[Brief description of the drawings]
FIG. 1 is according to the invention.Using light guide blockIt is a disassembled perspective view showing the external appearance of one Example of a plane illuminating device.
FIG. 2 is a sectional view of the flat illumination device in the embodiment shown in FIG.
FIG. 3 is a side view of the light guide block in the embodiment shown in FIG. 1;
4 is an extracted enlarged cross-sectional view taken along the line IV in FIG. 2. FIG.
FIG. 5 is a schematic view of the embodiment shown in FIG.LightIt is a graph showing the occupation rate of a deflection | deviation element.
FIG. 6 is according to the present invention.Using light guide blockIt is a disassembled perspective view showing the external appearance of the other Example of a plane illuminating device.
7 is an extraction enlarged plan view of a portion VII in FIG.
FIG. 8 shows in FIG.LightIt is an expansion perspective view showing the appearance of a deflection element.
[Explanation of symbols]
  11 Light guide block
  12 Frame
  13 Casing
  14 Fluorescent lamp
  15 Light incident end face
  16 Light exit end face
  17, 18 Side end face
  19 Connection end face
  20 Locking projection
  21 Locking recess
  22lightDeflection element
  23Prism body
  24 Top
  25 1st slope
  26 Second slope
  27 Reflector
  28 Light Reflective Cover
  29 Positioning recess
  30 Positioning convex part
  31 Base
  32 Conical surface
  33 Inclined cone surface
  34 Connection end face
  γ Opening angle of first side end face
  θ Angle formed by the light exit end and the second slope
  P Prism body spacing

Claims (10)

An elongated light incident end surface formed by a cylindrical concave lens surface, on which light is incident;
A light emitting end face portion that is located on the opposite side of the light incident end face portion and has a larger area than the light incident end face portion, and from which light is emitted;
A plurality of light deflecting elements that are randomly formed on the light emitting end face and deflect the light emitting direction from the light emitting end face, respectively;
Four side end surface portions including a pair of inclined surfaces, located between the light incident end surface portion and the light emitting end surface portion;
The formed with a pair of protruding state on the inclined surface, the second inclined surface of the light emission end surface portion first inclined surface portion facing the top and the light entrance end face side of this top as a boundary where the extending parallel to and opposite side has a section, guide blocks, characterized in that comprises a plurality of prisms for deflecting the traveling direction of light, respectively. The light deflecting element has an isosceles triangular opening whose base is parallel to the central axis of curvature of the concave lens surface of the light incident end face, and a pair of conical surfaces perpendicular to the light exit end face, The light guide block according to claim 1, wherein the light guide block is a triangular pyramid-shaped recess having an inclined conical surface including the base. 3. The light guide block according to claim 2, wherein the light deflection element is formed to have a larger occupation ratio toward a central portion side of the light emitting end face portion. A light incident end face portion on which light is incident;
A light emitting end face portion that is located on the opposite side of the light incident end face portion and has a larger area than the light incident end face portion, and from which light is emitted;
A plurality of light deflecting elements that are randomly formed on the light emitting end face and deflect the light emitting direction from the light emitting end face, respectively;
Four side end surface portions including a pair of inclined surfaces, located between the light incident end surface portion and the light emitting end surface portion;
A top portion formed in a protruding state on the pair of inclined surfaces and extending in parallel with the light emitting end surface portion, a first inclined surface portion facing the light incident end surface portion side from the top portion, and a second inclined surface on the opposite side A plurality of prism bodies each having a portion for deflecting the light traveling direction;
The comprising the light guide blocks you characterized in that the inclination angle of the pair of inclined surfaces is set larger the light emission end surface portion side with respect to the light emission end surface portion. A light incident end face portion on which light is incident;
A light emitting end face portion that is located on the opposite side of the light incident end face portion and has a larger area than the light incident end face portion, and from which light is emitted;
A plurality of light deflecting elements that are randomly formed on the light emitting end face and deflect the light emitting direction from the light emitting end face, respectively;
Four side end surface portions including a pair of inclined surfaces, located between the light incident end surface portion and the light emitting end surface portion;
A top portion formed in a protruding state on the pair of inclined surfaces and extending in parallel with the light emitting end surface portion, a first inclined surface portion facing the light incident end surface portion side from the top portion, and a second inclined surface on the opposite side A plurality of prism bodies each having a portion for deflecting the light traveling direction;
The comprising, angle between the second inclined surface portion of the prism body and the light emission end surface portion is set larger the light emission end surface portion side along the opposing direction between the light emission end surface portion and the light incident end face light guide blocks characterized by that. The ratio of the area of the front Symbol light deflection elements occupied per unit area of the beam emitting end face portion, claim 4 or claim 5, characterized in that the distance from the light entrance end face is set larger farther The light guide block described in 1. Spacing of the prism body along the opposing direction between the light emission end surface portion and the light incident end face portion, of claims 1 to 6, characterized in that it is narrower set as the light emission end surface portion side The light guide block according to any one of the above. The height of the top of the prism body is set to be higher toward the light emitting end face along the opposing direction of the light incident end face and the light emitting end face. Item 8. The light guide block according to any one of Items 7 . 2. The apparatus according to claim 1, further comprising at least a pair of connection end surface portions formed between the light emitting end surface portion and the side end surface portion and perpendicular to the light emitting end surface portion. The light guide block according to claim 8 . The light guide block according to claim 9 , wherein one of the pair of connection end surface portions has a locking projection and the other has a locking recess having a shape corresponding to the locking projection.

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