JP2007335209A - Planar lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin and lightweight planar lighting system which can be manufactured at a low cost, capable of suppressing brightness variations and emitting light having superior brightness distribution from a light emitting face. <P>SOLUTION: The planar lighting system emits emitted light from a light source as a planar light from a light emitting face, and includes: a planar optical member forming the light emitting face; a groove part projectingly formed on the light emitting face side positioned separated by a predetermined interval from the optical member; a box shaped frame composed of a bottom face structured of an inclined part approaching the light emitting face as it goes farther away from the groove part, and side faces formed between ends of the bottom face and the optical member; a linear light source disposed in the groove part of the frame; a reflection member disposed on a face opposite the optical member side of the linear light source and the inclined part of the bottom face of the frame; and an optical element disposed on the optical member side of the groove part of the frame. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a planar illumination device that diffuses light emitted from a light source and emits planar illumination light from a light exit surface to illuminate the interior and exterior, or a liquid crystal display panel, an advertising panel, an advertising tower, and a signboard The present invention relates to a planar illumination device used as a backlight for the above.

  Currently, a so-called direct type system in which a plurality of light sources such as cold-cathode tubes are arranged on the back surface of a liquid crystal panel is generally used for a planar illumination device used as a backlight unit of a large-sized liquid crystal television. It is used.

As such a direct type planar illumination device, for example, in Patent Document 1, a plurality of straight tube type cold cathode fluorescent lamps or straight tube type hot cathode lamps are composed of a reflecting plate and a light diffusing plate. The total luminous flux values of the two lamps arranged on the outermost side among the lamps arranged in parallel to each other in a plane are higher than the total luminous flux values of the lamps arranged on the inner side. In particular, there is described a backlight unit for a liquid crystal display device that aims to improve the uniformity of the luminance distribution of illumination light.
Japanese Utility Model Publication No. 5-4133

  By the way, in the direct type planar illumination device as described in the cited document 1, in order to improve the uniformity of the in-plane luminance distribution of illumination light, in principle, a light source and an optical member such as a diffusion plate are used. It is necessary to secure a sufficient interval between them. Therefore, in a liquid crystal display device using a direct type backlight unit, a thickness of about 30 mm in a direction perpendicular to the display surface of the liquid crystal display device is required in order to ensure a certain degree of luminance distribution uniformity.

  Thus, in the direct type backlight unit, in order to reduce the luminance unevenness, a certain thickness or more is required. Therefore, there is a problem that the luminance unevenness cannot be reduced and the thickness cannot be reduced.

  The present invention has been made in view of the above problems, and can be manufactured at low cost, brightness unevenness is suppressed, light having a good brightness distribution can be emitted from the light exit surface, and is thin and lightweight. An object is to provide a planar lighting device.

  In order to achieve the above-described object, a first aspect of the present invention is a planar illumination device that emits light emitted from a light source as planar light from a light exit surface, and forms the light exit surface. A planar optical member; a groove portion that is convexly formed on the light exit surface side at a position spaced apart from the optical member by a predetermined distance; a bottom surface that is configured by an inclined portion that approaches the light exit surface as the distance from the groove portion increases; and A box-shaped frame formed of a side surface formed between an end of the bottom surface and the optical member; a linear light source disposed in the groove of the frame; and the optical member side of the linear light source A planar illumination device comprising: a reflection member disposed on a surface opposite to the surface of the frame; and an inclined portion of the bottom surface of the frame; and an optical element disposed on the optical member side of the groove portion of the frame. I will provide a.

In the first aspect of the present invention, the optical element is preferably a lens having a biconvex cross section.
Alternatively, the optical element is preferably a plano-convex lens having a cross-sectional shape convex toward the linear light source.
Alternatively, the optical element is preferably a triangular prism having a cross-sectional shape that is convex on the side opposite to the linear light source.
Alternatively, the optical element is preferably an aspheric lens.

  Here, the frame preferably has the inclined surfaces formed on both side surfaces of the groove.

  A second aspect of the present invention is a planar illumination device that emits light emitted from a light source as planar light from a light exit surface, and a planar optical member that forms the light exit surface; A groove portion that is convexly formed on the light emission surface side at a position spaced apart from the optical member, a bottom surface that is configured by an inclined portion that approaches the light emission surface as it is separated from the groove portion, and an end portion of the bottom surface, and A box-shaped frame composed of side surfaces formed between the optical member, a linear light source disposed in the groove of the frame, and a surface opposite to the optical member side of the linear light source, And a planar illumination device comprising: a reflecting member disposed on an inclined portion of the bottom surface of the frame; and a plurality of columnar diffusers disposed between the optical member and the bottom surface of the frame. provide.

  Here, in the first and second aspects of the present invention, it is preferable that a side surface of the frame is covered with a reflective surface.

  Moreover, it is preferable that the said frame has at least 2 or more of the said groove part, and the said adjacent groove part is formed in parallel mutually.

Moreover, the said reflection member is a reflection-diffusion film, and the said reflection-diffusion film is affixed on the surface on the opposite side to the said optical member side of the said linear light source, and the inclination part of the bottom face of the said frame. Is preferred.
Alternatively, it is preferable that the reflection member is formed integrally with the frame, and the reflection member disposed on the inclined surface of the frame is formed by a reflective diffusion coating applied to the inclined surface of the frame. .
Alternatively, it is preferable that the reflecting member is formed integrally with the frame, and the reflecting member disposed on the inclined surface of the frame is formed by plating the inclined surface of the frame.

  Furthermore, it is preferable that the optical member includes a transmittance adjusting member.

Furthermore, another aspect of the present invention is a planar illumination device that emits light emitted from a light source as planar light from a light exit surface, the planar optical member that forms the light exit surface, At least one linear light source disposed at a predetermined distance from the optical member, and the optical source as the distance from the light source increases to a position facing the optical member on a surface of the linear light source opposite to the light source member. A reflective member disposed at an inclination to the member side; and a columnar optical element disposed on the light exit surface side of the linear light source, wherein the linear light source includes the reflective member and the optical element. The planar illumination device is characterized in that the entire surface is covered by the above.
In this aspect, it is preferable that the optical member, the linear light source, the reflecting member, and a frame for supporting and fixing the optical element are further included, and the frame has a surface on the reflecting member side on the optical member side. Preferably, the optical element is fixed to a surface of the groove portion on the optical member side. The groove portion accommodates the linear light source on the reflection member side.
Moreover, it is preferable that a reflective member is disposed on a side surface of the frame.
Furthermore, it is preferable to have two or more linear light sources, and the linear light sources are arranged in parallel to adjacent linear light sources.

  According to the present invention, it is possible to provide a thin and light planar illumination device that can suppress luminance unevenness and emit light having a good luminance distribution from the light emission surface, and can be manufactured at low cost.

The planar lighting device of the present invention will be described below.
FIG. 1 is a schematic perspective view showing a first embodiment of a planar illumination device of the present invention and showing an external appearance viewed from a light emitting surface side. 2A, 2B, 2C, and 2D are a front view, a bottom view, a side view, and a rear view of the planar illumination device shown in FIG. 1, respectively. FIG. 3 is a partial cross-sectional view of the first embodiment of the planar lighting device shown in FIG. In addition, in the following figures including these figures, in order to facilitate understanding, they are shown enlarged in the direction of the thickness of the planar lighting device.

  As shown in FIG. 1 and FIGS. 2A to 2D, the planar illumination device 10 includes a plurality of linear light sources 12 and emits uniform light from a rectangular light exit surface 14 a. 14, a housing 16 in which the lighting device main body 14 is housed, a rectangular opening 16a is formed on the light emitting surface 14a side (surface side), and the housing 16 is opposite to the light emitting surface 14a. An inverter storage unit 20 that stores a plurality of inverter units 18 that are attached to the side (rear surface side) and that is used to light each of the plurality of linear light sources 12, and a plurality of inverter units 18 that are stored in the inverter storage unit 20 And a power source 38 (see FIG. 6) for lighting the plurality of linear light sources 12 respectively.

Here, the illuminating device main body 14 is for emitting uniform light from the rectangular light emitting surface 14a, and basically, as shown in FIGS. 3, 4 and 5A, A plurality of linear light sources 12 and a bottom surface 22d having parallel grooves 22b respectively formed corresponding to the linear light sources 12, and four sides (outer edge portions) of the bottom surface 22d are formed perpendicular to the light emitting surface 14a. A box-shaped frame 22 having a rectangular light exit opening 22a on the surface opposite to the bottom surface 22d, and a rectangular shape disposed on the light exit opening 22a side of the frame 22. An optical member unit 24 having a rectangular plane that forms the light emitting surface 14 a, a reflection film 26 disposed on the inner surface (on the light emitting surface 14 a side) of the frame 22, and the parallel grooves 22 b along the linear light source 12. Placed on the light exit surface 14a side Columnar collimator lens 28 comprises a (hereinafter, a lens 28 to) and.
4 shows a unit structure including one unit frame 23 which is a constituent unit of the frame 22 in the lighting device main body 14, the lighting device main body 14 of this embodiment is shown in FIGS. As shown in a), a plurality of unit structures including one unit frame 23 are provided. Further, the optical member unit 24 disposed on the side of the light emission opening 22a of the frame 22, that is, the upper part of the frame 22, also has substantially the same size (area) as the light emission opening 22a.

The linear light source 12 is a linear or thin rod-like cold cathode tube (CCFL: see FIG. 6), and is opposite to the light exit surface 14a of the plurality of parallel grooves 22b of the frame 22 (a convex inner ) And are respectively connected to the inverter unit 18.
Here, in the present embodiment, a cold cathode tube is used as the linear light source 12, but the present invention is not limited to this, and the linear light source 12 may be any rod light source (linear light source). A linear light source such as a normal fluorescent tube, a hot cathode tube (HCFL), an external electrode tube (EEFL), or the like can be used in addition to the cold cathode tube (CCFL).
The inverter unit 18 and the power source 38 (see FIG. 6) for turning on and off the plurality of linear light sources 12 will be described later.

As shown in FIG. 5A, the frame 22 has a bottom surface 22d and side surfaces 22e provided perpendicular to the light exit surface 14a on the four sides of the bottom surface 22d, and is opposite to the bottom surface 22d. This is a box-shaped member having a rectangular light exit opening 22a formed on the side surface, and is formed by using various metal processing techniques such as press processing using a metal plate as a material. The frame 22 has a structure in which the unit frames 23 are repeatedly arranged in one direction (light guide direction).
The frame 22 is formed by pressing a metal plate or the like. However, the frame 22 may be formed by injection molding or extrusion molding using a resin as a material, and a frame having a desired shape and durability can be formed. There is no particular limitation.

  As shown in FIGS. 5A and 5B, the unit frame 23 has a rectangular individual light exit opening 23a, a thickest portion 23b parallel to one side thereof, and one side on both sides of the thickest portion 23b. The thin-walled end portion 23c (the thinnest portion 22c) formed in parallel and the bottom surface 22d of the frame 22 are configured so that the thickness decreases toward the thin-walled end portions 23c on both sides in a direction orthogonal to one side from the thickest portion 23b. Between the inclined surface 23d and the two inclined surfaces 23d, a parallel groove 22d formed parallel to one side at the approximate center of the unit frame, and a lens 28 described later are arranged along the parallel groove 22d. A lens holding mechanism 29 that holds both ends of a lens 28 described later is included.

As shown in FIG. 5B, the parallel groove 22b has a cross-section parallel to the light guide direction, in a direction parallel to one side of the light emission opening 22a of the frame 22 at the approximate center of the unit frame 23 of the bottom surface 22d. For example, it is formed in parallel to the light exit surface and in a direction perpendicular to the light guide direction. The parallel groove 22b has a shape in which two inclined surfaces intersect, is convexly formed on the light exit surface 14a side, and accommodates the linear light source 12.
In addition, a light incident window 22f for allowing light from the linear light source 12 to enter the inside of the frame 22 is formed on the inclined surface of the parallel groove 22b.

As shown in FIG. 5A, the light entrance window 22f is a rectangular opening formed on a substantially entire surface from one end of the inclined surface to the other end in the extending direction of the light source. In the illustrated example, the light incident window 22f is provided with ribs 22g that divide the light incident window 22f in the longitudinal direction. Thereby, the light entrance window 22f can be divided into a plurality of regions and the frame 22 can be reinforced, and deformation or distortion of the frame 22 can be prevented.
Note that the number and arrangement position of the ribs 22g are not limited to the illustrated example, and may be appropriately determined as necessary in consideration of prevention of luminance unevenness and securing of the strength of the parallel grooves.

Here, the frame 22 has a structure in which the above-described unit frames 23 are repeatedly arranged in one direction (light guide direction), and a rectangular opening formed by the four side surfaces 22e serves as one large light emission surface. Is.
As described above, it is preferable that the space inside the unit frame 23 is integrally formed at the boundary of the repetitive structure of the unit frame 23 without the adjacent unit frames 23 being separated from each other by a partition wall or the like. Thereby, it is possible to suppress the occurrence of luminance unevenness due to the decrease in luminance at the boundary position of the repetitive structure.
In addition, since more uniform light can be emitted, it is preferable not to provide a partition at the boundary between the unit frames 23. However, if necessary, the boundary (connecting portion) between the unit frames 23 also has a side surface. Similarly to the above, a partition wall may be provided between the bottom surface and the optical member. Thus, by arranging the partition walls at regular intervals, for example, the strength of the frame can be increased, and deformation of the frame, bending of the optical member toward the frame side, and the like can be more reliably prevented.

  As shown in FIG. 5 (a), the frame 22 may be a single frame connection body integrally formed with a plurality of unit frames 23 connected to each other. However, the cost can be reduced and the yield can be improved. In consideration of ease of manufacture, a large frame having a light exit opening 22a with a large area may be formed by connecting a plurality of integrally connected frame bodies of a plurality of unit frames 23. In this case, the frame connection body is enlarged by connecting the thin end portions 23c of the unit frames 23 of the adjacent frame connection bodies in the light guide direction orthogonal to the parallel grooves 22b, and the light emission opening 22a has a large area. May be used. At this time, it is needless to say that the uniform planar light emitting openings of the plurality of frame connecting bodies are connected flush with each other, and the uniform light emitting openings 22a are formed in the frame 22. In this case, it is preferable that the optical member unit 24 disposed on the upper portion of the frame 22 has substantially the same size (area) as the light emission opening 22 a of the frame 22.

Further, the light entrance windows 22f formed in the parallel grooves 22b and the parallel grooves 22b of the frame 22 are not limited to the above-described shapes, and may be various shapes.
Here, by making the light entrance window 22f larger than the parallel groove 22b, it is possible to efficiently guide the light emitted from the linear light source 12 into the frame 22 and to improve the light utilization efficiency. .
Further, by arranging a part of the frame 22 directly above the linear light source 12, the intensity of light directed from the linear light source 12 directly above it can be limited. Thereby, generation | occurrence | production of the bright line right above a linear light source can be prevented, and generation | occurrence | production of brightness irregularity can be suppressed.
It is preferable that the parallel grooves 22b are appropriately shaped appropriately so as not to prevent the lens 28, which will be described in detail later, from being disposed at a predetermined position at a predetermined angle and along the linear light source. Thereby, the emitted light from the linear light source 12 can be guided in a desired direction.

As a linear light source, a linear light source having a mechanism for limiting the intensity of light traveling directly from the linear light source, or the intensity of light traveling in the light guiding direction rather than the light traveling directly from the linear light source. It is also preferable to use a linear light source having a mechanism for increasing the size of light, that is, a linear light source having high directivity in the light guide direction. By using such a linear light source, generation of bright lines immediately above the linear light source can be suitably prevented.
Further, when such a linear light source is used, it is not necessary to configure the parallel groove 22b so that the intensity of light according to the emission direction of the light emitted from the linear light source 12 can be adjusted, and further, the parallel groove 22b is provided. Alternatively, the linear light source 12 may be disposed directly on the bottom surface 22d. Thereby, generation | occurrence | production of the bright line right above a linear light source can be prevented, generation | occurrence | production of brightness irregularity can be suppressed, and also the shape of the flame | frame 22 can be simplified. Also, by simplifying the shape of the frame 22, the frame 22 can be manufactured easily and inexpensively.

Incidentally, the inclined surface 23d constituting a part of the bottom surface 22d is not limited to being formed as a flat surface with an inclination angle with respect to the upper surface of the individual light emitting opening 23a as shown in the figure, and is formed from a curved surface. Alternatively, it may be composed of a plurality of planes whose inclination angle gradually changes. Here, these curved surfaces and planes need to be parallel to the parallel grooves 22b.
The profile of the cross section of the parallel groove 22b and the inclined surface 23d perpendicular to the parallel groove 22b has high uniformity of the luminance of the illumination light emitted from the individual light emission surface 23a, and there is little decrease in luminance. Although not particularly limited, a shape similar to the shape on the bottom surface side of the light guide plate disclosed in Japanese Patent Application No. 2004-325251 relating to the application of the present applicant can be applied.

The reflective film 26 is a reflective member that is formed using white titanium oxide or the like and is disposed along the inner surface side of the inclined surface 23 d of the frame 22. The light emitted from the linear light source 12 is reflected on the frame 22. Reflecting toward the opening, that is, the light exit surface, the utilization efficiency of the illumination light is improved.
Further, although the reflective film 26 is provided on the inner surface side of the inclined surface of the frame 22, the present invention is not limited to this, and a white reflective diffusion paint may be applied to the inner surface side of the inclined surface 23 d of the frame 22. The inner surface of the 22 inclined surfaces 23d may be plated. Thus, since the frame and the reflecting member can be formed integrally, the apparatus can be made simpler, and can be made thinner and lighter.
Such a reflection member is disposed not only on the inner surface side of the inclined surface 23d of the frame 22, but also on the inner surface side of the frame 22 including the inner surface side of the side surface 22e of the frame 22 and the inner surface side of the bottom surface 22d. It is preferable.

  The reflector 27 is disposed below the linear light source 12 so as to block each parallel groove 22 d of the frame 22, specifically, on the opposite side of the optical member unit 24 of the linear light source 12, and emitted from the linear light source 12. It is a reflecting member that reflects light. Thereby, the light inject | emitted from the linear light source 12 can enter into the inside of the flame | frame 22 without leaking, and the utilization efficiency of illumination light can be improved.

The lens 28 is a columnar lens whose length is substantially equal to the length of the linear light source 12 in the longitudinal direction and whose cross-sectional shape has a biconvex shape, and the inclined surface of the parallel groove 22b in which the linear light source 12 is accommodated. , That is, in the vicinity of the linear light source 12 along the linear light source 12. In the illustrated example, the lens 28 is held by the lens holding mechanism 29 of the frame 22 and is fixed to both sides of the linear light source 12 with the linear light source 12 interposed therebetween.
The lens 28 emits the light emitted from the linear light source 12 in a predetermined direction as a parallel light flux or directional light. As described above, the light emitted from the linear light source 12 is converted into a parallel light beam or directional light by the lens 28, so that the light emitted from the linear light source 12 can reach farther. Further, it is possible to prevent the luminance only in the vicinity of the light source from increasing, and to prevent the bright line from being generated in the vicinity of the linear light source. Thereby, luminance unevenness is suppressed and illumination light with high luminance uniformity can be obtained.

Here, the emission direction of the parallel light beam (or directional light) may be appropriately determined according to the inclination angle and shape of the inclined surface 23d, the characteristics of the optical member unit 24 described later, and the like.
The lens holding mechanism 29 is not particularly limited as long as it has a shape that can fix the lens 28 to the frame 22, but there is uneven luminance in an area near the end of the linear light source of the planar illumination device. It is preferable that the shape does not occur.

  The optical member unit 24 makes the uniform illumination light emitted from the light emission opening 22a of the frame 22 more uniform, and emits the illumination light with further improved uniformity from the light emission surface 14a of the illumination device body 14. As shown in FIGS. 3 and 4, a microprism array parallel to the parallel grooves 22b of the frame 22 and forming the light emission surface 14a is formed, and passes through the light emission openings 22a of the frame 22 to form an optical member. A prism sheet 24a that improves the brightness by improving the condensing property of the illumination light emitted from the frame 22 toward the unit 24, and a diffusion sheet 24b that similarly diffuses and equalizes the illumination light emitted from the frame 22. Similarly, it is used to reduce the luminance unevenness of the illumination light emitted from the frame 22, and responds to the uneven brightness on the transparent film 25a and this surface. Disposed Te, and a transmittance adjusting member 24c provided with a large number of transmittance adjusters 25b consisting of a diffuse reflector.

The transmittance adjusting member 24c is preferably provided on the side of the frame 22 close to the light exit opening 22a. However, the arrangement order and the number of the prism sheets 24a and the diffusion sheets 24b are not limited, and the optical member The prism sheet 24a, the diffusion sheet 24b, and the transmittance adjusting member 24c used in the unit 24 are not limited to those described above, and the illumination light emitted from the frame 22 through the light emission opening 22a of the frame 22 is more uniform. Any optical member may be used as long as it can be used. The prism sheet 24a may be disposed on the light emission opening 22a side of the reflecting member 26 on the bottom surface 22d side of the frame 22 (on the side opposite to the bottom surface 22d of the frame 22).
Regarding optical members used in the optical member unit 24 including the prism sheet 24a, the diffusion sheet 24b, and the transmittance adjusting member 24c, see [0028] to [0033] in Japanese Patent Application Laid-Open No. 2005-23497 related to the present applicant. What is disclosed can be applied.

  The illuminating device main body 14 includes one parallel groove 22b, the linear light source 12 is disposed at the storage position thereof, the unit frame 23 in which the reflection film 26 is formed on the inner surface side of the inclined surface 23d, and the individual light emission thereof. A plurality of unit structures having optical member units 24 arranged on the opening side 23a are arranged in parallel in the light guide direction. In this case, it goes without saying that the opening surfaces of the individual light emitting openings 23a of the unit frame 23 are connected to be flush with each other, and the opening surfaces of the light emitting openings 22a of the frame 22 are uniform.

In the illuminating device main body 14 configured as described above, the light emitted from the linear light source 12 accommodated in the parallel groove 22b enters the inside of the frame 22, and the incident light passes through the lens 28. The inside of the frame 22 advances in the light guide direction from the thickest portion 23b side toward the thin end portion 23c side. A part of the incident light is directed to the transmittance adjusting member 24c of the optical member unit 24, and a part of the incident light is scattered by the transmittance adjusting body 25b and emitted from the light exit surface 14a of the illuminating device main body. It is reflected and returns to the inside of the frame 22. The light returning to the inside of the frame 22 is reflected by the reflecting member 26 disposed along the inclined surface 23d that forms the bottom surface of the frame 22, and is similarly emitted from the light emitting surface 14a. On the other hand, the light that does not directly go in the direction of the optical member unit 24 travels through the frame 22 and is reflected by the reflection film 26 arranged along the inclined surface 23d, and is similarly emitted from the light emitting surface. In this way, light from a plurality of linear light sources can be made into uniform illumination light emitted from the light exit surface 14a of the illuminating device body 14.
The illumination device body 14 is basically configured as described above.

  On the other hand, as shown in FIG. 3, the housing 16 accommodates and supports the illuminating device main body 14, and is sandwiched and fixed from the light emitting surface 14a side and the reflecting member 26 side, and the upper surface is open. The lighting device main body 14 is housed and supported from above, and the lower housing 30 that covers the four side surfaces thereof, and the opening 16a on the upper surface that is smaller than the rectangular light emitting surface 14a of the lighting device main body 14 are provided. A rectangular opening is formed, the lower surface is opened, and the upper housing 32 that covers the lighting device body 14 and the lower housing 30 in which the lighting device main body 14 and the lower housing 30 are housed, including the four side surfaces thereof. The concave (U-shaped) folding member 34 inserted between the side wall of the lower housing 30 and the side wall of the upper housing 32, and the bottom surface 22d of the frame 22 are supported on the bottom of the lower housing 30. And the entire lighting device body 14 And a frame support member 36 for lifting. Although not shown in FIG. 3, an inverter storage unit 20 (see FIG. 2) that stores a plurality of inverter units 18 is attached to the back side of the lower housing 30.

Here, as a method for joining the lower housing 30 and the folding member 34, and a method for joining the folding member 34 and the upper housing 32, various known methods such as a method using bolts and nuts, a method using an adhesive, and the like. Can be used.
The upper housing 32 is larger than the lower housing 30 and at least outer wall surfaces at both ends of the lower housing 30 parallel to the parallel grooves 22b of the frame 22 of the lighting device body 14 or the linear light source 12 housed therein. The folding members 34 need to be disposed in the gaps between the inner wall surfaces of the upper housing 32 facing each other. The folding members 34 are arranged on the four side surfaces of the housing 16 with respect to the lower housing 30. You may arrange | position between a side wall and the side wall of the upper housing | casing 32. FIG. Moreover, it is preferable to attach the reinforcement member which reinforces the recessed part of the concave folding member 34. FIG.
By arranging the folding member 34 in this manner, the rigidity of the housing 16 can be increased, and the warpage of the frame 22 can be corrected, or the warpage of the frame 22 can be prevented from occurring. Thereby, for example, a planar illumination device having good optical characteristics such as being able to emit light uniformly and efficiently without causing uneven brightness or the like can be obtained. Moreover, the rigidity of the housing | casing 16 can be made higher by attaching the reinforcement member which reinforces the recessed part of the folding | turning member 34, and it can prevent more appropriately that the flame | frame 22 arises. Thereby, a planar lighting device having better optical characteristics can be obtained.

  The frame support portion 36 is formed of a resin such as polycarbonate. In the illustrated example, the frame support portion 36 is a convex member having a shape obtained by inverting the shape of the bottom surface 22 d of the thinnest portion 22 c of the frame 22. The body 30 is disposed at a predetermined interval for each thinnest portion 22c of the frame 22 along the bottom surface 22d of the frame 22, but the present invention is not limited to this, and the bottom surface 22d of the frame 22 The convex part which has the shape which reversed the shape may be the continuous member provided with the predetermined space | interval.

Note that the housing 16 is provided with a fastener such as an L-shaped metal fitting that joins the four corners, or between the prism sheet 24a of the planar device main body 14 and the peripheral portion of the opening 16a of the upper housing 30. An elastic member made of an elastic material such as rubber or a protective member for protecting the entire upper surface of the prism sheet 24a of the planar apparatus main body 14 may be provided.
The housing 16 is basically configured as described above.

Next, driving devices for the plurality of linear light sources 12 housed in the parallel grooves 22b of the frame 22 of the planar apparatus main body 14 will be described.
The driving device 37 shown in FIGS. 6A and 6B drives the linear light source 12 such as a plurality of CCFLs, that is, turns on and off, and drives the illumination of the planar lighting device 10. A plurality of inverter units 18 respectively connected to the linear light sources 12 such as a plurality of CCFLs, and a power source 38 to which the plurality of inverter units 18 are connected. FIG. 6B shows a block diagram of the drive unit 37 for lighting the linear light source 12 such as one CCFL in order to show the detailed configuration of the inverter unit 18.
The power source 38 is a DC power source that outputs a DC voltage, for example, a DC voltage of 24V DC. This DC voltage is supplied to each of the plurality of inverter units 18 connected to the power source 38.

  The inverter unit 18 is connected to the drive circuit 18a that generates a primary AC signal having a predetermined frequency of a predetermined voltage (for example, 650 Vp-p) from the DC voltage supplied from the power supply 38, and the linear light source 12, and is connected to the drive circuit. A transformer 18b that boosts the primary AC signal generated in 18a to a high-voltage secondary AC signal (for example, 6500 Vp-p, 1000 to 2400 Vrms) necessary for lighting the linear light source 12 such as CCFL; The tube current detection circuit 18c for detecting the tube current connected to the linear light source 12 such as CCFL and the tube current output from the tube current detection circuit 18c are fed back, and the drive circuit 18a receives the primary AC signal. A voltage-controlled oscillation circuit 18d that oscillates a clock (fundamental wave) having a predetermined frequency for generation according to the fed-back tube current That.

In the present invention, the drive device 37 of the linear light source 12 is configured as described above, so that the plurality of linear light sources 12 can be lighted simultaneously and uniformly efficiently, stably, and uniformly, with uniform brightness. Can emit light.
In the present invention, the plurality of linear light sources 12 are turned on at the same time. However, only a part of them may be turned on by the inverter unit 18 or these may be switched.
The linear light source driving device and the planar illumination device are basically configured as described above.

  Although the planar lighting device 10 of the above-described embodiment is provided with the inverter storage portion 20 on the back side of the housing 16 and stores a plurality of inverter units 18, the planar lighting device of the present invention is limited to this. 7, between the lower housing 30 and the upper housing 32 in the periphery of the opening 16 a of the housing 16 on the side orthogonal to the linear light source 12, as in the planar illumination device 11 shown in FIG. 7. A space may be provided to serve as the inverter storage unit 20, and a plurality of inverter units 18 may be stored. By doing so, the back surface of the planar illumination device 11, that is, the back surface of the housing 16 can be flattened, and attachment to a ceiling or a wall surface can be facilitated.

  As described above, according to the present invention, the lens is disposed in the light guiding direction in the vicinity of the linear light source, and the reflecting member disposed on the surface facing the light emitting surface is closer to the light emitting surface as the distance from the light source is increased. In this way, the light emitted from the light source is converted into parallel light or directional light, and reflected by the inclined reflecting member toward the light emission surface, thereby emitting uniform light from the light emission surface. be able to. With the above-described configuration, the region where light is diffused can be shortened by efficiently reflecting and diffusing light, so that the device can be reduced in thickness and weight.

Further, by using a biconvex lens as the lens 28 as in the planar illumination device 10 of the above-described embodiment, the light is further delivered, that is, the light emitted from the linear light source 12 is transmitted to the linear light source in the frame 22. Thus, it is possible to guide to a position away from 12, and luminance unevenness of illumination light can be reduced.
In addition, as a lens arrange | positioned in the vicinity of the linear light source 12, this invention is not limited to this, For example, the planoconvex lens 40 shown in FIG. In this case, the plano-convex lens 40 is arranged with the curved surface side in the direction of the light exit surface and the flat surface side in the direction of the light entrance window.
Further, as shown in FIG. 9, a prism 42 having a triangular prism shape may be used instead of the lens 28. In this case, the plane side facing the convex portion of the prism 42 is arranged in the direction of the light entrance window.
Further, instead of the lens 28, an aspheric lens may be used. The shape of the aspheric lens can be determined from the shape of the frame 22, the characteristics of the linear light source 12, the characteristics of the optical member unit 24, the arrangement position of the aspheric lens (for example, the positional relationship with the linear light source 12), and the like. it can. Thereby, the brightness nonuniformity of illumination light can be reduced.

  Moreover, although the frame 22 of the planar lighting device 10 of the present embodiment has a box shape in which the bottom surface and the side surface are formed of plate-like members, the frame of the present invention is not limited to this, You may comprise only the frame which consists of an outline of the above-mentioned frame 22. FIG. By disposing the reflecting member as the bottom and side surfaces of such a frame, a frame having the same function as the above-described frame 22 can be configured.

In the present embodiment, CCFL, HCFL, EEFL, or the like can be used as the linear light source. However, the planar illumination device according to the present invention is not limited to this, and a light emitting diode (LED) or a semiconductor is used. A linear light source can also be configured using a light source such as a laser (LD).
FIG. 10 shows an illuminating device main body of a planar illuminating device using LEDs as a light source as another example of the planar illuminating device of the present embodiment. In the illustrated example, an LED array 44 formed by arranging LED light sources on a substrate at a predetermined interval in one direction (a direction from the front to the back in FIG. 10) is housed in the parallel groove 22b as a linear light source.

When CCFL or the like is used as a linear light source, a device that converts direct current into alternating current, more specifically, a device that converts direct current power into high frequency alternating current power is used as an inverter unit for lighting the linear light source. When an LED, LD, or the like is used as the light source for the linear light source, a device (rectifier) that converts alternating current into direct current may be used as the inverter unit. In the present invention, the inverter unit (converter) includes a device that converts alternating current into direct current and a device that converts direct current into alternating current.
In addition, when an LED or LD is used as the linear light source, a cylindrical or prismatic transparent light guide having the same length as the parallel groove of the frame is used, and the top and bottom surfaces of the light guide are used. An LED may be arranged so that light from the LED enters from the top and bottom surfaces of the light guide and exits from the side of the light guide.
Heretofore, the first embodiment of the planar lighting device according to the present invention has been described in detail.

Hereinafter, a second embodiment of the planar lighting device according to the present invention will be described in detail.
FIG. 11 is a schematic cross-sectional view showing the illumination device main body 52 of the planar illumination device 50 of the present embodiment. As shown in FIG. 11, the illumination device main body 52 includes a linear light source 12, a frame 22, an optical member unit 24, a reflective film 26 disposed on the inner surface of the frame 22, and a light emission surface of the linear light source 12. Comprises a reflector 27 disposed on the opposite surface and a plurality of diffusers 54.
Here, the linear light source 12, the frame 22, the optical member unit 24, the reflection film 26, and the reflector 27 are basically the same as the members used in the lighting device main body 14 of the first embodiment described above. Therefore, the same reference numerals are given and the detailed description thereof is omitted, and points specific to the planar illumination device 50 will be described in detail below.

In the illuminating device main body 52, a plurality of columnar (cylinder-shaped) diffusers 54 are filled in the frame 22.
The diffuser 54 is an optical element that deflects and diffuses the light emitted from the linear light source 12 in various directions inside the frame 22, and uses a transparent resin material, and is approximately the length of the linear light source 12. They are formed to the same length. As shown in FIG. 11, each of the plurality of diffusers 54 is oriented in substantially parallel to the linear light source 12 and filled in the frame 22.

Thus, in the planar illumination device 50 in which the plurality of diffusers 54 are filled in the frame 22, the light emitted from the linear light source 12 and introduced into the frame 22 is diffused in the frame 22. 54 is transmitted, refracted, or reflected, and its traveling direction is deflected in various directions.
In this manner, the light emitted from the linear light source 12 is guided to a position away from the linear light source 12 in the frame 22 while being diffused by the diffuser 54 filled in the frame 22. In this process, the light that has reached the light emission opening 22a of the frame 22 is emitted as planar illumination light from the light emission surface 52a of the illuminating device main body 52 as in the first embodiment.

  In this way, by arranging a plurality of diffusers inside the frame instead of arranging the lens in the vicinity of the linear light source, the luminance unevenness is suppressed and a good luminance distribution is obtained as in the first embodiment. Light can be emitted from the light exit surface, and a thin and lightweight planar illumination device can be obtained.

Here, as the diffuser, for example, a plastic optical fiber (POF) can be used.
A plastic optical fiber (hereinafter referred to as an optical fiber) is a cylindrical member that is formed using a flexible material and has a length substantially the same as the length of the linear light source 12.
The optical fiber includes a core portion made of an organic compound having a polymer as a matrix and a clad portion made of an organic compound having a refractive index different from that of the core portion. For example, an additive such as a stabilizer can be added to the core part and the clad part for the purpose of improving the weather resistance and durability of the clad part and the core part. The clad portion is made of a polymer, preferably has a refractive index lower than that of the core portion, and preferably has transparency to light emitted from a point light source. The core portion is made of a polymer, and contains a scattering particle that scatters light using a material that is transparent to light emitted from a point light source.
The scattering cross section of the scattering particles contained in the optical fiber is Φ, the half length of the optical fiber in the direction of incidence of light is L _G , and the density of scattering particles contained in the optical fiber (number of particles per unit volume) is N _{When p} and the correction coefficient are K _C , the relationship that the value of Φ · N _p · L _G · K _C is 2.0 or more and 7.0 or less is satisfied. Since the optical fiber includes scattering particles that satisfy such a relationship, it is possible to emit illumination light from the side surface that is uniform and has less luminance unevenness.
Moreover, the plasticizer mentioned above can also be added to the resin material which comprises an optical fiber. Thereby, the softness | flexibility of an optical fiber is improved and a flexible diffuser can be obtained.

  In the present embodiment, the diffuser 54 has a circular cross-sectional shape. However, the present invention is not limited to this, and the cross-sectional shape may be a triangle, a quadrangle, an ellipse, or a star. For example, according to various conditions such as the shape of the frame, the refractive index of the diffuser 54, the filling rate, etc., so that illumination light with uniform brightness can be emitted from the light exit surface of the planar illumination device, What is necessary is just to determine a cross-sectional shape suitably.

Here, the plurality of diffusers 54 accommodated in the frame 22 are preferably formed by adhering contact surfaces to each other with an adhesive or the like. Alternatively, the diffusers may be bonded to each other by filling a gap between a plurality of stacked diffusers 54 with a transparent resin material having flexibility. In this way, by fixing the diffuser 54 so that the arrangement of the diffuser 54 does not change inside the frame 22, the diffuser 54 moves and unevenness in luminance due to the change in the optical path inside the frame 22 occurs. Occurrence can be prevented.
In order to allow the light from the linear light source to enter deeply, that is, to sufficiently reach the light from the linear light source even at a position away from the linear light source in the frame, the gap between the diffusers that are in contact with each other It is preferable that an air layer is interposed in the air, and by interposing such an air layer, the occurrence of uneven luminance is further suppressed when used as a thin light guide member, and even when the frame is thinned, the occurrence of uneven luminance is prevented. Can be suppressed.
Moreover, the plasticizer mentioned above can also be added to the resin material which comprises a diffuser. Thereby, a softness | flexibility is improved and it can be used as a flexible diffuser.
Heretofore, the second embodiment of the planar lighting device according to the present invention has been described in detail.

Next, a third embodiment of the planar lighting device according to the present invention will be described in detail.
In FIG. 12, the illuminating device main body of 3rd Embodiment of the planar illuminating device which concerns on this invention is shown. Here, FIG. 12A is a schematic cross-sectional view of the lighting device body, and FIG. 12B is a schematic perspective view of the lighting device body.

As shown in FIGS. 12A and 12B, the planar illumination device 100 includes a linear light source 12 and a unit frame 123 having a wedge-shaped frame shape in a cross section perpendicular to the linear light source 12. The frame 122, the reflection film 126 disposed on the inner surface of the frame 122, the lens 128 disposed in the frame 122 along the linear light source 12, and the light that emits light from the linear light source 12 as illumination light An optical member unit 24 that forms the emission surface 114a, and a reflector 127 that is disposed so as to cover the linear light source 12 with the frame 122 and that reflects the light emitted from the linear light source 12 to prevent light leakage. A lighting device main body 114 having a driving device (not shown) for driving the linear light source 12 is provided. Further, the lighting device main body 114 and the driving device are housed in a housing (not shown) to constitute the planar lighting device 100.
In the present embodiment, except for the shape of the frame 122 and the arrangement method of the linear light source 12, the configuration is basically the same as that of the planar illumination device of the first embodiment. A detailed description thereof will be omitted. Further, since the drive device and the housing have the same configuration as that described in the first embodiment, detailed description thereof is omitted.

FIG. 13 shows a side view of the frame 122 according to the present embodiment. As shown in FIG. 13, the frame 122 is a box-like member having an open upper surface, and includes a plurality of unit frames 123.
In the unit frame 123, the thickness of the frame decreases from the thickest portion 123b formed at one end parallel to one side of the frame 122 toward the thin end portion 123c formed at the other end parallel to one side of the frame 122. The inclined surface 123 d that is inclined in this manner constitutes the bottom surface 122 d of the frame 122.
Further, the linear light source 12 is disposed outside the frame 122 along the thick end portion 123b, and a light incident window 122f for allowing light from the linear light source 122 to enter the frame 122 is provided. It is formed on the side surface of the frame 122 on the thick end portion 123b side.
Further, in order to arrange the lens 28 along the light entrance window, lens holding mechanisms 29 are formed at both ends in a direction parallel to the linear light source 12.

  As shown in FIGS. 12A and 12B, the lens 128 is disposed at the thick end portion 123 b of the frame 123 along the light incident window 122 f, that is, along the linear light source 12. The lens 128 is disposed along the light entrance window 122f, and both ends thereof are held by the lens holding mechanism 29.

The reflection film 126 is disposed along the inclined surface 123d on the inner surface side of the frame 122, and reflects the light emitted from the linear light source 12 toward the light emission opening 122a portion of the frame 122, that is, the light emission surface. Light utilization efficiency can be improved.
Similarly to the first embodiment, the reflector 127 is a member that improves the utilization efficiency of illumination light by allowing light emitted from the linear light source 12 to enter the inside of the frame 122 without leaking. In the present embodiment, the reflector 127 is disposed so as to sandwich the linear light source 12 disposed outside the frame 122 on the thick end portion 123 b side of the frame 122 with the frame 122.
Further, the optical member unit 24 is disposed along the light emission opening 122 a of the frame 122.

  Similarly to the first embodiment, the planar lighting device main body 114 is held at both ends by the unit frame 123, the reflection film 126 disposed on the inclined surface 123d, and the lens holding mechanism 29 and enters the unit frame 123. Lens 128 arranged along optical window 122f, linear light source 12 arranged outside thick end 123b of unit frame 123, reflector 127 arranged along linear light source 12, and unit frame A plurality of unit structures each including an optical member unit 24 disposed on the individual light exit opening 123a side of 123 are arranged in parallel in a light guide direction orthogonal to the linear light source 12 and parallel to the light exit surface 114a. .

  In the illumination device main body 114 configured as described above, the light emitted from the linear light source 12 enters the frame 22. The incident light passes through the lens 128 to become a parallel light flux, travels in the frame 122 from the thick end portion 123b toward the thin end portion 123c, and is disposed along the inclined surface 122b of the frame 122. The light is reflected by the reflective film 126 and travels toward the transmittance adjusting body 24 c of the optical member unit 24. Further, the other part of the light entering the light source frame 122 goes to the transmittance adjusting member 24 c of the optical member unit 24. A part of the light is scattered by the transmittance adjusting body 25 b and emitted from the light exit surface 114 a of the illuminating device main body 114, and the other part is totally reflected and returns to the inside of the frame 122. The light returning to the inside of the frame 122 is reflected by the reflecting member 126 arranged along the inclined surface 123d that forms the bottom surface of the frame 122 and is similarly emitted from the light emitting surface 114a. On the other hand, the light that does not go directly to the optical member unit 24 travels through the frame 122 and is reflected by the reflection film 126 disposed along the inclined surface 123d, and is similarly emitted from the light emitting surface. In this way, light from a plurality of linear light sources can be made uniform illumination light.

As described above, by arranging the lens along the linear light source inside the frame, the luminance unevenness is suppressed and light having a good luminance distribution can be emitted from the light emitting surface as in the first embodiment. And a thin and lightweight planar lighting device can be obtained.
Heretofore, the third embodiment of the planar lighting device according to the present invention has been described in detail.

Hereinafter, a fourth embodiment of the planar illumination device according to the present invention will be described in detail.
FIG. 14 is a schematic cross-sectional view showing the illumination device main body 152 of the planar illumination device 150 of the present embodiment.
As shown in FIG. 14, the illuminating device main body 150 includes a linear light source 12, a frame 122, an optical member unit 24, a reflective film 26 formed on the inner surface of the frame 122, a reflector 27, and a frame 122. A plurality of filled diffusers 154.
The planar illumination device 150 according to the present embodiment is basically the same as the planar illumination device 100 according to the third embodiment except that a diffuser 154 is provided instead of the lens 128, so that the same member is used. Are denoted by the same reference numerals, and detailed description thereof is omitted.

As described above, the lighting device main body 150 is filled with a plurality of diffusers 154 having a columnar shape inside the frame 122. The diffuser 154 is the same as that described in the second embodiment, and a detailed description thereof will be omitted.
In this way, by filling the frame 122 with the plurality of diffusers 154, the light emitted from the linear light source 12 and introduced into the frame 122 is filled into the frame 22 as in the second embodiment. The diffuser 154 is transmitted, refracted, and reflected, and its traveling direction is deflected in various directions.
In this manner, the light emitted from the light source 12 is guided to a position away from the linear light source 12 in the frame 122 while being diffused by the diffuser 54 filled in the frame 122. In this process, the light that has reached the light emission opening 122a of the frame 122 is emitted as planar illumination light from the light emission surface 152a of the illuminating device main body 152 as in the third embodiment.

Here, like the second embodiment, the plurality of diffusers 154 filled in the frame 122 are preferably fixed by bonding their contact surfaces with an adhesive or the like. Alternatively, the diffusing bodies 154 may be bonded and fixed by filling a gap between the plurality of diffusing bodies 154 that are stacked and arranged with a transparent resin material having flexibility. By fixing the arrangement of the diffuser 154 in this way, it is possible to prevent the occurrence of luminance unevenness due to the change of the optical path of the light inside the frame 122.
Further, as in the second embodiment, it is preferable that an air layer is interposed in the gap between the diffusers that are in contact with each other. By interposing such an air layer, the linear light source can be separated from the linear light source. Can be sufficiently reached, and even when the frame is thinned, the occurrence of uneven brightness can be suppressed. Moreover, the said optical fiber can be used as a diffuser like 2nd Embodiment.

  In the planar lighting device of the fourth embodiment, as described above, by arranging a plurality of diffusers inside the frame, the luminance unevenness is suppressed and a good luminance distribution is obtained as in the other embodiments described above. The light which it has can be inject | emitted from a light-projection surface, and a thin and lightweight planar illuminating device can be obtained.

  As described above, the planar illumination device of the present invention described in detail can be suitably used as a backlight of a liquid crystal display device.

  Although the planar lighting device of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications and changes may be made without departing from the spirit of the present invention. It is.

It is a schematic perspective view which shows the external appearance seen from the light-projection surface side of 1st Embodiment of the planar illuminating device of this invention. (A), (b), (c), and (d) are the front view of the planar illuminating device shown in FIG. 1, the side view of a longitudinal direction, the side view of a transversal direction, and a rear view, respectively. It is a fragmentary sectional view of one Embodiment of the planar illuminating device shown in FIG. It is a schematic perspective view which shows the unit structure which comprises the illuminating device main body of the planar illuminating device shown in FIG. (A) is a schematic perspective view of the frame used for the illuminating device main body shown in FIG. 3, (b) is a diagram which shows the cross-sectional shape of one unit frame of the illuminating device main body shown in FIG. (A) is the wiring diagram of one Embodiment of the drive device of the linear light source used for the planar illuminating device shown in FIG. 2, (b) is the block of the drive device of the linear light source shown to (a). FIG. It is a schematic block diagram which shows the other Example of the planar illuminating device of this invention. It is a schematic sectional drawing which shows the principal part of the other Example of the illuminating device main body of 1st Embodiment. It is a schematic sectional drawing which shows the principal part of the other Example of the illuminating device main body of 1st Embodiment. It is a schematic sectional drawing which shows the principal part of the other Example of the illuminating device main body of 1st Embodiment. It is a schematic sectional drawing which shows the illuminating device main body of the planar illuminating device of the 2nd Embodiment of this invention. (A) is a schematic sectional drawing which shows the illuminating device main body used for the planar illuminating device of 3rd Embodiment which concerns on this invention, (b) is the schematic perspective view. It is a side view which shows a part of flame | frame used for the planar illuminating device shown in FIG. It is a schematic sectional drawing which shows the illuminating device main body used for the planar illuminating device of the 4th Embodiment of this invention.

Explanation of symbols

10, 11, 100, 150 Planar illumination device 12 Linear light source 14, 52, 114, 152 Illumination device main body 14a, 52a, 114a, 152a Light exit surface 16 Housing 16a Opening 18 Inverter unit 18a Drive circuit 18b Transformer 18c Tube current detection circuit 18d Voltage controlled oscillation circuit 20 Inverter housing part 22, 122 Frame 22a, 122a Light exit opening 22b, 122b Parallel groove 22c Thinnest part 22d, 122d Bottom face 22e, 122e Side face 22f, 122f Light incident window 22g Rib 23, 123 Unit frame 23a, 123a Individual light emission opening 23b Thickest part 23c, 123c Thin end part 23d, 123d Inclined surface 24 Optical member unit 24a Prism sheet 24b Diffusion film 24c Transmittance adjustment member 25a Transparent sheet 25b Transparent Excess ratio adjuster 26, 126 Reflective film 27, 127 Reflector 28, 128 Lens,
29 Lens holding mechanism 30 Lower housing 32 Upper housing 34 Folding member 36 Frame support member 37 Drive device 38 Power source 40 Plano-convex lens 42 Prism 123b Thickest end

Claims (13)

A planar illumination device that emits light emitted from a light source as planar light from a light exit surface,
A planar optical member forming the light exit surface;
A groove portion convexly formed on the light emitting surface side at a position spaced apart from the optical member, a bottom surface formed of an inclined portion that approaches the light emitting surface as the distance from the groove portion, and an end portion of the bottom surface, and A box-shaped frame composed of side surfaces formed between the optical member;
A linear light source disposed in the groove of the frame;
A reflective member disposed on a surface opposite to the optical member side of the linear light source and an inclined portion of a bottom surface of the frame;
An planar illumination device comprising: an optical element disposed on the optical member side of the groove portion of the frame.   The planar illumination device according to claim 1, wherein the optical element is a lens having a biconvex cross-sectional shape.   The planar illumination device according to claim 1, wherein the optical element is a plano-convex lens having a cross-sectional shape that is convex on the side opposite to the linear light source side.   2. The planar illumination device according to claim 1, wherein the optical element is a triangular prism whose cross-sectional shape is convex on the side opposite to the linear light source.   The planar illumination device according to claim 1, wherein the optical element is an aspheric lens.   The planar illumination device according to any one of claims 1 to 5, wherein the frame has the inclined surface formed on both side surfaces of the groove portion. A planar illumination device that emits light emitted from a light source as planar light from a light exit surface,
A planar optical member forming the light exit surface;
A groove portion convexly formed on the light emitting surface side at a position spaced apart from the optical member, a bottom surface formed of an inclined portion that approaches the light emitting surface as the distance from the groove portion, and an end portion of the bottom surface, and A box-shaped frame composed of side surfaces formed between the optical member;
A linear light source disposed in the groove of the frame;
A reflective member disposed on a surface opposite to the optical member side of the linear light source and an inclined portion of a bottom surface of the frame;
A planar illumination device comprising: a plurality of columnar diffusers disposed between the optical member and a bottom surface of the frame.   The planar lighting device according to claim 1, wherein a side surface of the frame is covered with a reflective surface. The frame has at least two of the groove portions,
The planar lighting device according to claim 1, wherein the adjacent groove portions are formed in parallel to each other. The reflective member is a reflective diffusion film,
The planar illumination according to claim 1, wherein the reflection diffusion film is attached to a surface of the linear light source opposite to the optical member side and an inclined portion of a bottom surface of the frame. apparatus. The reflecting member is formed integrally with the frame,
The planar illumination device according to any one of claims 1 to 9, wherein the reflecting member disposed on the inclined surface of the frame is formed by a reflective diffusion coating applied to the inclined surface of the frame. The reflecting member is formed integrally with the frame,
The planar illumination device according to claim 1, wherein the reflection member disposed on the inclined surface of the frame is formed by plating the inclined surface of the frame.   The planar illumination device according to claim 1, wherein the optical member includes a transmittance adjusting member.

Images