JP4652970B2 - Surface lighting device - Google Patents

Description

  The present invention has a light guide plate that diffuses light emitted from a light source and emits illumination light from a light exit surface, and is a planar illumination device that illuminates indoors or outdoors, or a liquid crystal display panel, an advertising panel, an advertising tower, The present invention relates to a planar lighting device used as a backlight for a signboard or the like.

  Conventionally, a liquid crystal display device uses a backlight unit that irradiates light from the back side of a liquid crystal panel (LCD) to illuminate the liquid crystal panel. The backlight unit usually includes a light source for illumination, a light guide plate that diffuses light emitted from the light source and irradiates the liquid crystal panel, and a prism sheet and a diffusion sheet that uniformize the light emitted from the light guide plate. Constructed using.

In recent years, this backlight unit is not only used in a liquid crystal display device as described above, but also illuminates the interior or exterior, or irradiates a liquid crystal display panel, a notification panel, a notification tower, a signboard, etc. from the back side. It is also used as a planar lighting device.
The same applies to this planar illumination device, but recent liquid crystal display devices are required to be thin and have low power consumption, and various shapes of light guide plates have been proposed. (Patent Literature 1, Patent Literature 2, Patent Literature 3 and Patent Literature 4)

FIG. 10 is a schematic cross-sectional view of a liquid crystal display device using the light guide plate disclosed in Patent Document 1.
The backlight (backlight unit) shown in FIG. 1 includes a liquid crystal display panel 122, a fluorescent tube 112, a light guide plate 111, and a diffusion plate 123.
In Patent Document 1, in order to obtain a backlight of a liquid crystal display device that can realize a reduction in size and weight and a reduction in cost and power consumption of the liquid crystal display device without reducing the irradiation amount of the backlight 100. In addition, a rectangular irradiation surface, a rectangular cross-section groove 114 that is cut out in parallel with the long side at the center of the short side and into which the light source is inserted, and toward the both side surfaces of the long side across the groove 114 A light guide plate 111 having a back surface formed so that the plate thickness is gradually reduced is disclosed.

  In Patent Document 2, the frame of the liquid crystal display device can be narrowed and the thickness can be reduced, and in order to obtain a bright backlight unit with high light utilization efficiency, the width direction of the recess for arranging the light source is described. A light guide (light guide plate) is disclosed in which the parallel cross-sectional shape is a parabolic shape with the depth direction as the main axis.

  Further, in Patent Document 3, in order to keep the in-plane brightness of the display panel uniform and to provide high-intensity illumination, a plurality of refractive indexes are sequentially increased on the C-shaped highly reflective layer. A light guide plate is disclosed in which the plate-shaped optical fracture layers are laminated and the light diffusion layer is brightened by the light emitted from the respective light emission end faces. Here, the recess for installing the light source has a triangular shape.

  Further, in Patent Document 4, in order to improve the liquid crystal backlight for a large liquid crystal display surface of a wall-mounted television, a plurality of light guide plates are arranged in parallel, and a predetermined number of linear light sources are arranged between the light guide plates. Realizes large-scale backlight with uniform brightness.

  However, all of the light guide plates disclosed in Patent Documents 1 to 4 have unevenness in the light emitted from the emission surface, and cannot emit uniform and high-intensity light from the emission surface. Have

Japanese Patent Laid-Open No. 08-062426 JP 10-1333027 A JP 05-249320 A JP 2001-42327 A

  Therefore, as shown in Japanese Patent Application No. 2004-170425, the present inventor passes the center of the rod-shaped light source and the maximum thickness D of the thick portion of the light guide plate unit with respect to the diameter R of the rod-shaped light source, and the light emission surface. By making the distance L from the vertical surface to the end surface of the thin end portion that is a joint portion with the adjacent light guide plate unit 1.6R ≦ L and 0.6R ≦ D, the thin and light weight can be increased in size. Provided are a light guide plate having a shape that can realize a light emission surface and that has high light emission efficiency from the light emission surface with respect to light emitted from a light source, and a planar illumination device and a liquid crystal display device using the same. ing. In particular, since the planar lighting device is thin and lightweight as described above, it is effective for ceiling lighting, floor lighting, wall lighting, and the like that are directly embedded in a flat part of a building.

  In the case of pursuing the design to the planar illumination device as described above, as in the conventional illumination device, for example, there is a method of giving accents to members around the light source (lamp), In the above-mentioned planar lighting device that realizes thinness and light weight, if a method of giving accents to members around the light source is used to give design, the weight and thickness of the planar lighting device are increased. There arises a problem that the result is a contradiction with respect to thinness and light weight.

  An object of the present invention is to eliminate the problems based on the above-mentioned conventional technology, to form a pattern in the light that is thin and light, and to generate light having regular brightness changes, that is, to improve design. It is in providing the planar illuminating device which has.

In order to achieve the above object, the present invention provides a light source, a light guide plate that emits light from the light source from a light exit surface, and light that is disposed on the light exit surface of the light guide plate and is emitted from the light guide plate. An optical member unit that emits light from the light exit surface with the light emitting surface uniform, and a rule that is arranged on the light exit surface of the optical member unit and that is formed of interference fringes from the uniform light emitted from the light exit surface of the light guide plate specific has a pattern formation member for generating light having a brightness change, and the pattern forming member, halftone dots formed by the regularity of a pattern on a surface of a sheet-like optical member having a light transmissive property It is at least two comprises a screen pattern formation member, at least two of the dot pattern formation member, are laminated, to Rukoto the uniform light to light having a regular intensity changes consisting of the interference fringes Surface shape characterized by There is provided an illumination device.

  In this invention, it is preferable that the said pattern formation member produces | generates the light which has the regular brightness change of a pattern different from the pattern of the halftone dot currently formed in the said halftone dot pattern formation member.

  In the present invention, the halftone dots are preferably formed in a pattern in which a basic unit arrangement pattern is repeated.

  In the present invention, it is preferable that the optical member is a film or sheet made of a transparent resin, and the halftone dots are formed by printing.

  In the present invention, the halftone dots are preferably formed using ink of any one of cyan, yellow, magenta, and a mixture thereof.

  In the present invention, the area occupied by the halftone dots with respect to the area of the surface forming the halftone dots of the optical member is preferably 5% to 95%.

  In the present invention, the halftone dot is preferably an aggregate of dots having a quadrilateral, circular, rectangular, triangular, rhombus, star, ellipse or crescent shape.

  In the present invention, the halftone dots are preferably formed in a striped or grid pattern.

  In the present invention, it is preferable that the pattern forming member generates light having a geometric brightness change.

Further, in the present invention, the halftone dot patterns of the two halftone dot pattern forming members do not coincide when the halftone dot pattern forming members are overlapped in parallel with the light exit surface of the optical member unit. It is preferable that it exists in.
  In the present invention, it is preferable that the optical member unit has a prism sheet that improves the light collecting property of the light emitted from the light emitting surface of the light guide plate to improve the luminance.
  In the present invention, it is preferable that the optical member unit has a diffusion sheet that diffuses and uniformizes the light emitted from the light exit surface of the light guide plate.
  In the present invention, it is preferable that the optical member unit includes a transmittance adjusting member that reduces unevenness in luminance of light emitted from the light exit surface of the light guide plate.

Furthermore, in order to achieve the above object, the present invention provides a light source, a light guide plate that emits light from the light source from a light exit surface, and a light exit surface of the light guide plate that is disposed on the light guide plate. An optical member unit that makes the emitted light uniform and emits it from the light exit surface, and is arranged on the light exit surface of the optical member unit, and interferes with the uniform light emitted from the light exit surface of the light guide plate A pattern forming member for generating light having regular brightness changes composed of stripes, and the pattern forming member has a regular pattern on the front and back surfaces of a light-transmitting sheet-like optical member. At least one halftone dot pattern forming member in which halftone dots are formed, and at least one halftone dot pattern forming member converts the uniform light into light having regular brightness changes composed of the interference fringes. and wherein the There is provided a Jo lighting device.

  The planar illumination device of the present invention is thin and lightweight, can form a pattern on outgoing light to be emitted, can generate light having regular brightness changes, and can exhibit design. .

The planar lighting device of the present invention will be described below.
FIG. 1 is a schematic perspective view showing an embodiment of the planar lighting device according to the present invention and showing an appearance viewed from the 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 an 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. 8) for turning on 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 rectangular light exit surface 22a are formed on the side of the light exit surface 14a, and a plurality of parallel grooves 22b for accommodating the plurality of linear light sources 12 are formed on the back side thereof. A light guide plate 22 having the thinnest portion 22c having the thinnest thickness from the light exit surface 22a side to the back side between the grooves 22b and the light exit surface 22a side of the light guide plate 22 are disposed, and a rectangular light exit surface is arranged. An optical member unit 24 having a rectangular flat surface to be formed, and pattern formation which is disposed on the light output surface side of the optical member unit 24 and has a rectangular flat surface forming a rectangular light output surface 14a. Unit 40 and rear surface of light guide plate 22 And a reflecting member 26 disposed along the 2d.
4 shows only the unit light guide plate 23 having one parallel groove 22b which is one unit constituting the light guide plate 22, but as shown in FIG. The illuminating device main body 14 is formed by a light guide plate 22 including a plurality of unit light guide plates 23, and an optical member unit 24 disposed on the upper portion of the light guide plate 22 is also formed with a pattern formed on the upper portion of the optical member unit 24. Needless to say, the unit 40 also has substantially the same size (area) as the light exit surface 22 a of the light guide plate 22.

The linear light source 12 is disposed in the plurality of parallel grooves 22 b of the light guide plate 22 and is connected to the inverter unit 18. The linear light source 12 used in the present invention is a linear, that is, a thin rod-shaped cold cathode tube (CCFL: see FIG. 8), and is used to illuminate a surface. Here, 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-shaped light source (linear light source), In addition to the cold cathode fluorescent lamp (CCFL), for example, a normal fluorescent tube (hot cathode fluorescent tube; HCFL), an external electrode tube (EEFL), a light emitting diode (LED), a semiconductor laser, or the like can be used. When an LED is used as the linear light source 12, a cylindrical or prismatic transparent light guide having the same length as the parallel grooves 22b of the light guide plate 22 is used, and the upper surface of the light guide and An LED light source may be used in which an LED is disposed on the bottom surface, LED light is incident from the top and bottom surfaces of the light guide, and is emitted from the side surface of the light guide.
The inverter unit 18 and the power source 38 (see FIG. 8) for turning on and off the plurality of linear light sources 12 will be described later.

The light guide plate 22 includes a plurality of unit light guide plates 23 as shown in FIG.
The unit light guide plate 23 is made of a transparent resin, and as shown in FIG. 5B, a rectangular individual light exit surface 23a, a thick portion 23b parallel to one side thereof, and both sides of the thick portion 23b. A thin end portion 23c formed parallel to one side, and the thickness is reduced from the thick portion 23b toward the thin end portions 23c on both sides in a direction perpendicular to the one side, constituting the back surface 22d of the light guide plate 22; It has an inclined back surface portion 23e that forms a curved inclined surface 23d, and a parallel groove 22b that is formed parallel to one side of the thick portion 23b and that houses the light source 12. That is, the unit light guide plate 23 includes one parallel groove 22b, and has an individual light exit surface 23a having the same length as the light exit surface 14a of the light guide plate 22 in a direction parallel to the parallel groove 22b. .
As the structures and materials of the unit light guide plate 23 and the light guide plate 22, those disclosed in [0029] to [0030] of Japanese Patent Application Laid-Open No. 2005-23497 related to the applicant's application can be applied.

The parallel grooves 22b may have two hyperbolic shapes that intersect each other as shown in the illustrated example. However, any shape having a luminance uniforming effect such as a triangular shape, a U shape, or a parabolic shape may be used. The one disclosed in Japanese Patent Application Laid-Open No. 2005-23497 related to the application of the present applicant can be applied.
Further, the inclined surface 23d may be formed of a curved surface as in the illustrated example, or may be a flat surface having a constant inclination angle with respect to the individual light emitting surface 23a, or a plurality of inclination angles that gradually change. 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 is not particularly limited, but the luminance uniformity of the illumination light emitted from the individual light emission surface 23a is high, and If there is little decrease in luminance, the present invention is not particularly limited, but the one disclosed in Japanese Patent Application No. 2004-325251 relating to the application of the present applicant can be applied.

The unit light guide plate 23 allows illumination light emitted from the linear light source 12 stored in the parallel groove 22b to enter, and is inclined in a direction parallel to the individual light exit surface 23a from the thick portion 23b toward the thin end portion 23c. The illumination light propagated through the back surface portion 23e and the illumination light reflected by the inclined surface 23d and the reflecting member 26 disposed along the inclined surface 23d and along the inclined surface 23d constituting the back surface are uniformly distributed from the individual light emitting surface 23a. Is emitted as a simple illumination light.
Thus, uniform illumination light is emitted from the light exit surface 22a of the light guide plate 22 to which the plurality of unit light guide plates 23 are connected.
As shown in FIG. 5A, the light guide plate 22 has a structure in which the unit light guide plates 23 adjacent to each other in the direction orthogonal to the parallel groove 22b are connected to each other by the thin end portions 23c. The connecting portion forms the thinnest portion 22 of the light guide plate 22. In this case, it goes without saying that the light emitting surfaces 23a of the plurality of unit light guide plates 23 are connected to one another, and the light guide plate 22 forms a uniform light emitting surface 22a.

  As shown in FIG. 5A, the light guide plate 22 may be a single light guide plate connector integrally formed with a plurality of unit light guide plates 23 connected, but cost reduction and yield are achieved. In consideration of the improvement of the above and the ease of manufacture, a plurality of integrally formed light guide plate assemblies of unit light guide plates 23 may be connected to form a large-sized light guide plate having a large area light output surface 22a. In this case, the light guide plate connecting body connects the thin end portions 23c of the unit light guide plates 23 of the adjacent light guide plate connecting bodies and connects them in the direction orthogonal to the parallel grooves 22b to increase the size and emit light. The surface 22a may be increased in area, or the end portions orthogonal to the thin-walled end portion 23c of the adjacent light guide plate connector are connected to each other and connected in a direction parallel to the parallel groove 22b to increase the size and emit light. The surface 22a may be increased in area, or these may be performed simultaneously and connected in a direction parallel to and perpendicular to the parallel grooves 22b to further increase the size of the light emission surface 22a. At this time, it is needless to say that the uniform planar light emitting surfaces of the plurality of light guide plate connectors are connected to each other, and the light guide plate 22 forms a uniform planar light emitting surface 22a. Absent. In this case, the linear light source 12 is preferably a linear light source having the length of the parallel groove 22b of the light guide plate 22 to which the light guide plate connector is connected, and is disposed above the light guide plate 22. The optical member unit 24 preferably has substantially the same size (area) as the light exit surface 22 a of the light guide plate 22.

  The optical member unit 24 makes the uniform illumination light emitted from the light emission surface 22a of the light guide plate 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, microprism arrays parallel to the parallel grooves 22 b of the light guide plate 22 are formed, and light from the light guide plate 22 is emitted. A prism sheet 24a that improves the condensing property of the illumination light emitted from the emission surface 22a and improves the brightness; a diffusion sheet 24b that diffuses and equalizes the illumination light emitted from the light emission surface 22a of the light guide plate 22; It is used to reduce the luminance unevenness of the illumination light emitted from the light exit surface 22a of the light guide plate 22, and is arranged on the transparent film 25a and this surface according to the luminance unevenness, And a transmittance adjusting member 24c provided with a large number of transmittance adjusters 25b made of diffusing reflector.

The transmittance adjusting member 24c is preferably provided on the side close to the light exit surface 22a of the light guide plate 22. However, the arrangement order and the number of arrangement of the prism sheets 24a and the diffusion sheets 24b are not limited. The prism sheet 24a, the diffusion sheet 24b, and the transmittance adjusting member 24c used in the member unit 24 are not limited to those described above, and the illumination light emitted from the light emitting surface 22a of the light guide plate 22 can be made more uniform. Any optical member may be used as long as it can be used. The prism sheet 24a may be disposed between the light guide plate 22 and the reflecting member 26 on the back surface 22d side, or a prism row may be formed on the back surface 22d of the light guide plate 22 itself.
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 [0038] to [0039] in Japanese Patent Application Laid-Open No. 2005-23497 related to the application of the present applicant. What is disclosed can be applied.

The pattern forming unit 40, which is a feature of the present invention, forms a pattern on the uniform illumination light emitted from the optical member unit 24, and forms a halftone dot pattern that will be described in detail later from the light exit surface 14 a of the illuminating device body 14. Illumination light having a regular brightness change in a pattern different from the pattern of the members 46 and 52 is generated, and illumination light having a geometric brightness change, that is, illumination light having design properties is emitted.
As shown in FIGS. 3 and 4, the pattern forming unit 40 is composed of a first halftone dot pattern forming member 46 and a second halftone dot pattern forming member 52 in the present embodiment. The member 52 is disposed closer to the light incident side than the first halftone dot pattern forming member 46. The first halftone dot pattern forming member 46 and the second halftone dot pattern forming member 52 may be disposed in close contact with each other, or may be disposed at a predetermined interval.

As shown in FIG. 4, the first halftone dot pattern forming member 46 has a transparent film 42 and a large number of halftone dots 44 arranged on the surface of the transparent film 42. On the other hand, as shown in FIG. 4, the second halftone dot pattern forming member 52 includes a transparent film 48 and a large number of halftone dots 50 arranged on the surface of the transparent film 48.
The first halftone dot pattern forming member 46 and the second halftone dot pattern forming member 52 are formed by a halftone dot pattern (a pattern of the first halftone dot pattern forming member 46) and a halftone dot 50. Since the configuration is basically the same except for the pattern (the pattern of the second halftone dot pattern forming member 52), the following description will be made using the first halftone dot pattern forming member 46 as a representative example. The pattern formed on the first halftone dot pattern forming member 46 and the pattern formed on the second halftone dot pattern forming member 52 will be described in detail later.

  The transparent film 42 (48) has a film-like shape, and includes PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate), PMMA (polymethyl methacrylate), benzyl methacrylate, MS resin, and other acrylic resins. Or an optical member such as COP (cycloolefin polymer).

  The halftone dot 44 (50) is a dot having a predetermined transmittance and a quadrilateral, circular, rectangular, triangular, rhombus, star-shaped, elliptical, crescent-shaped, or the like. It is arranged on the entire surface on the unit side, and forms a regular pattern (halftone dot pattern) on the surface of the transparent film 42.

For example, in the example shown in FIG. 6A (FIG. 6B), the halftone dot 44 is a dot having a square shape, and is surrounded by a dotted line in the pattern formed on the entire surface of the transparent film 42. A portion having the regularity is formed as a basic unit 46a (52a) of the pattern, and such a basic unit 46a (52a) is repeatedly formed on the entire surface of the transparent film 42, thereby forming a regular pattern.
Here, FIG. 6A is a view showing an example of an arrangement pattern of the halftone dots 44 of the first halftone dot pattern forming member 46, and FIG. 6B is a halftone dot pattern of the second halftone dot pattern forming member 52. It is a figure which shows an example of the arrangement pattern of the point 50. FIG. Moreover, when these are incorporated in the illuminating device main body 14 shown in FIG. 4, it shall be incorporated so that the upper left corner in FIG. 6 may coincide with the front corner in FIG.

  The halftone dots 44 are arranged such that the occupied area with respect to the surface area of the first halftone dot pattern forming member 46 (transparent film 42) is 5% to 95%. The lower limit of the area occupied by the halftone dots 44 with respect to the first halftone dot pattern forming member 46 is 5%, and if the area occupied by the halftone dots exceeds 95%, the pattern forming unit 40 emits light. A sufficient pattern cannot be formed for the illumination light.

  The color of the halftone dots 44 is not particularly limited, but when formed by printing, any one of cyan, magenta, yellow, and a mixed color ink used for general printing is used. It is preferably formed using colored ink. As a result, the halftone dots 44 allow various color lights to be emitted from the pattern forming unit 40.

Here, as described above, the difference between the pattern formed on the first halftone dot pattern forming member 46 and the pattern formed on the second halftone dot pattern forming member 52 will be described with reference to FIG.
As shown in FIG. 6A, the pattern formed on the first halftone dot pattern forming member 46, that is, the pattern formed by arranging the halftone dots 44 on the entire surface of the transparent film 42, is a basic unit. A regular pattern 46a is repeatedly arranged.
On the other hand, the pattern formed on the second halftone dot pattern forming member 52, that is, the pattern formed by arranging the halftone dot 50 on the entire surface of the transparent film 48 is also the pattern first halftone dot pattern formation. Similar to the pattern of the member 46, as shown in FIG. 6B, the basic unit 52a is a regular pattern that is repeatedly arranged. However, the pattern of the second dot pattern forming member 52 is the first mesh. Compared with the pattern of the point pattern forming member 46, the shape shifted by half the width a of the basic unit toward the right side in the drawing, that is, the pitch is shifted.

That is, in the present invention, the pattern of the first halftone dot pattern forming member 46 and the pattern of the second halftone dot pattern forming member 52 are arranged in the direction of the arrow shown in FIG. There is a non-matching relationship when superimposed in parallel.
By arranging the first halftone dot pattern forming member 46 and the second halftone dot pattern forming member 52 in this way, that is, two regular halftone dot pattern forming members having both regular patterns are shifted from each other. By arranging in the pattern, an interference fringe (moire) different from the regular pattern of the halftone dot pattern forming member is generated, so that the illumination light having a regular brightness change can be generated from the pattern forming unit 40.

In the present invention, the pattern of the halftone dot pattern forming member is not limited to the above example and has regularity, and the halftone dot pattern forming members are overlapped in parallel with the light emitting surface 14a of the illuminating device body 14. Any pattern may be used as long as the patterns do not match when combined. That is, the pattern formed on one halftone dot pattern forming member and the pattern formed on the other halftone dot pattern forming member may be completely different patterns, or the halftone dot size, pitch, and shape may be different from each other. Good. That is, the patterns may be created so that the spatial frequencies of the patterns formed on the respective halftone dot pattern forming members are different.
In addition, the pattern formed on one halftone dot pattern forming member and the pattern formed on the other halftone dot pattern forming member may be exactly the same pattern, but in this case, each halftone dot pattern forming member The halftone dot pattern forming members may be arranged by shifting or rotating the other in parallel with each other so that the patterns do not coincide with each other.
More specifically, for example, a pattern 60 regularly arranged with a triangle as a basic unit as shown in FIG. 7A may be used, or a pair of star shapes as shown in FIG. The pattern 62 arranged regularly may be used. The triangle used for the pattern 60 and the star shape used for the pattern 62 may both be one halftone dot or a plurality of halftone dots.
Further, the pattern of the halftone dot pattern forming member may be a striped pattern 64 as shown in FIG. 7C or a lattice pattern 66 as shown in FIG. 7C. good. Both patterns 64 and 66 may be formed by arranging a plurality of halftone dots continuously without a gap. That is, in the present invention, it is also possible to form a pattern using a line shape such as the pattern 64 or the pattern 66 by arranging a plurality of halftone dots linearly and continuously without a gap.

In the illustrated example, as described above, by arranging the pattern of the second halftone dot pattern forming member 52 with the pitch shifted from the pattern of the first halftone dot pattern member 46, the halftone dot pattern is formed. When the pattern forming members are overlapped in parallel to the light emitting surface, the patterns of the halftone dot pattern forming members are not matched, but in the present invention, the halftone dot pattern forming members are arranged on the light emitting surface. The method of arranging the patterns so that the patterns of the halftone dot pattern forming members do not match when superposed in parallel is not limited to this method. For example, when two halftone dot pattern forming members are used, a pattern formed on one halftone dot pattern forming member is used as a reference pattern, and this reference pattern is centered on any position in the pattern. A method of forming a pattern generated by rotation on the other halftone dot pattern forming member, that is, a pattern formed on one halftone dot pattern forming member is rotated with respect to the other halftone dot pattern forming member. The method of arranging in the shape is mentioned.
In the illustrated example, two halftone dot pattern forming members are used. However, the present invention is not limited to this, and the halftone dot pattern forming members are parallel to the 14 light emitting surfaces 14a. If the patterns of the halftone dot pattern forming members do not match when superimposed, three or more halftone dot pattern forming members may be used as necessary.

The reflecting member 26 used in the illuminating device main body 14 is disposed along the back surface 22 d of the light guide plate 22 and is for improving the utilization efficiency of the illumination light emitted from the linear light source 12. A reflective sheet 26a that is disposed along the back surface 22d of the light guide plate 22 excluding the parallel grooves 22b on the back side where the grooves 22b are formed, reflects light leaking from the back surface of the light guide plate 22 and reenters the light guide plate 22; The light guide plate 22 is arranged on the back surface of the linear light source 12 so as to block the parallel grooves 22b of the light guide plate 22 between the adjacent reflection sheets 26a. And a reflector 26b for making the reflected light incident from the side wall surface of 22b.
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 light guide plate assembly 14 is housed and supported from above, and the lower housing 30 that covers the four side surfaces of the light guide plate assembly 14 and the opening 16a on the upper surface that is smaller than the rectangular light emitting surface 14a of the illuminating device body 14 are provided. The upper casing is formed so as to cover the light guide plate assembly 14 and the lower casing 30 in which the lower opening 30 is accommodated including the four side surfaces thereof. 32, a concave (U-shaped) folding member 34 fitted between the side wall of the lower housing 30 and the side wall of the upper housing 32, and the back surface of the light guide plate 22 disposed at the bottom of the lower housing 30 22d is supported through the reflecting member 26, and the planar illumination is performed. The entire apparatus main body 14 also has a light guide plate supporting member 36 for supporting. 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 light guide plate 22 of the illuminating device body 14 or the linear light source 12 housed therein. The folding member 34 needs to be disposed in each gap between the inner wall surface of the upper casing 32 and the upper casing 32 opposed to the lower casing 30 on the four side surfaces of the casing 16. It may be arranged between the side wall of the upper housing 32 and the side wall of the upper housing 32. Moreover, it is preferable to attach the reinforcement member which reinforces the recessed part of the concave folding member 34. FIG.
By disposing the folding member 34 in this way, the rigidity of the housing 16 can be increased, and light can be emitted uniformly and efficiently. On the other hand, the light guide plate 22 is likely to warp due to the presence of the parallel grooves 22b. Even so, it is possible to correct the warp or prevent the light guide plate 22 from warping, and to obtain good optical characteristics without causing uneven brightness. 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 connection light-guide plate 22 warps. Thereby, better optical characteristics can be obtained.

The light guide plate support 36 is formed of a resin such as polycarbonate. In the illustrated example, the light guide plate support 36 is a convex member having a shape obtained by inverting the shape of the back surface 22d of the thinnest portion 22c of the light guide plate 22. Although it arrange | positions at predetermined intervals for every thinnest part 22c of the light-guide plate 22 along the back surface 22d of the light-guide plate 22 at the bottom part of the lower housing | casing 30, this invention is not limited to this, A light-guide plate It may be a continuous member in which convex portions having a shape obtained by inverting the shape of the back surface 22d of 22 are provided at a predetermined 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 14a 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 light guide plate 22 of the planar device body 14 will be described.
The drive device 37 shown in FIGS. 8A and 8B 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 illumination 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. 8B 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, by configuring the drive device 37 of the linear light source 12 in this way, the plurality of linear light sources 12 are lit simultaneously and uniformly efficiently, stably and safely, 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. In the peripheral portion of the opening 16a of the casing 16 on the side orthogonal to the linear light source 12, like the planar illumination device 11 shown in FIG. 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, when the halftone dot pattern forming members are overlapped in parallel to the 14 light exit surfaces 14a, the halftone dot pattern forming member in which the regular patterns do not coincide with each other is used. By realizing it, various illumination patterns can be imparted to the light emitted from the pattern forming unit, thereby providing a planar illumination device that is thin, lightweight, and has design properties.

  In the above illustrated example, two halftone dot pattern forming members having a regular pattern formed on either surface are used. However, the present invention is not limited to this, and from one direction. A halftone dot pattern forming member in which a regular pattern is formed on the front and back surfaces of the transparent film may be used so that the regular patterns formed by halftone dots do not match when viewed. Accordingly, a single halftone dot pattern forming member can impart a pattern to the light emitted from the light exit surface 14a of the illuminating device body 14, and is a low-cost, thin, lightweight, and design surface A state lighting device can be provided.

  Note that each of the above-described planar illumination devices has a configuration in which a halftone dot pattern forming member is fixed, but the present invention is not limited to this. For example, when two or more halftone dot pattern forming members are used, one may be fixed and the other may be automatically or intermittently moved using a moving device. Moreover, it is good also as a structure which moves all the halftone dot pattern formation members automatically with a moving apparatus. Moreover, it can also comprise so that a halftone dot pattern formation member may be moved manually. Thereby, the planar illuminating device with high designability which produces | generates the illumination light which has a fluid pattern can be provided.

  As described above, the planar illumination device and the liquid crystal display device of the present invention have been described in detail. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the gist of the present invention. Of course it is also good.

It is a schematic perspective view which shows the external appearance seen from the light-projection surface side of one 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 of the planar illuminating device main body corresponding to one unit light-guide plate used for the planar illuminating device shown in FIG. (A) is a schematic perspective view of the light-guide plate used for the planar illuminating device shown in FIG. 3, (b) shows the cross-sectional shape of one unit light-guide plate of the planar illuminating device main body shown in FIG. FIG. (A) is a figure which shows an example of the arrangement pattern of the halftone dot of a 1st halftone dot pattern formation member, (b) is a figure which shows an example of the arrangement pattern of the halftone dot of a 2nd halftone dot pattern formation member. is there. (A)-(d) It is a figure which shows an example of the pattern formed in a halftone dot pattern formation member. (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 other embodiment of the planar illuminating device of this invention. It is a schematic sectional drawing of the liquid crystal display device using the conventional light-guide plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 11 Planar illuminating device 12 Linear light source 14 Illuminating device main body 14a Light emission surface 16 Case 16a Opening 18 Inverter unit 18a Drive circuit 18b Transformer 18c Tube current detection circuit 18d Voltage control oscillation circuit 20 Inverter accommodating part 22 Light guide plate 22a Light exit surface 22b Parallel groove 22c Thinnest portion 22d Back surface 23 Unit light guide plate 23a Individual light exit surface 23b Thick portion 23c Thin end portion 23d Inclined surface 23e Inclined back surface portion 24 Optical member unit 24a Prism sheet 24b Diffusion film 24c Transmittance adjustment Member 25a Transparent sheet 25b Transmittance adjusting body 26 Reflective member 26a Reflective film 26b Reflector 30 Lower housing 32 Upper housing 34 Folding member 36 Light guide plate support member 37 Drive device 38 Power supply 40 Pattern forming unit 42, 48 Transparent fill 44, 50 halftone dot 46 first halftone dot pattern forming member 52 second halftone dot pattern forming member 46a, 52a basic unit 60, 62, 64, 66 pattern 100 backlight 111 light guide plate 112 fluorescent tube 114 groove 122 liquid crystal display panel 123 Diffuser

Claims (14)

A light source;
A light guide plate that emits light from the light source from a light exit surface;
An optical member unit that is disposed on the light exit surface of the light guide plate and uniformly emits the light emitted from the light guide plate and exits from the light exit surface;
A pattern forming member that is disposed on the light exit surface of the optical member unit and that generates light having a regular brightness change composed of interference fringes from uniform light emitted from the light exit surface of the light guide plate and, have,
The pattern forming member comprises at least two halftone dot pattern forming members in which halftone dots are formed in a regular pattern on the surface of a light-transmitting sheet-like optical member,
At least two of the dot pattern formation member, are laminated, a planar illumination device according to claim to Rukoto to light having a regular intensity changes made to the uniform light from the interference fringes.   The planar illumination device according to claim 1, wherein the pattern forming member generates light having a regular brightness change in a pattern different from a halftone dot pattern formed on the halftone dot pattern forming member.   The planar illumination device according to claim 1, wherein the halftone dots are formed in a pattern in which a basic unit arrangement pattern is repeated.   The planar illumination device according to any one of claims 1 to 3, wherein the optical member is a film or sheet made of a transparent resin, and the halftone dots are formed by printing.   The planar illumination device according to any one of claims 1 to 4, wherein the halftone dots are formed using ink of any one of cyan, yellow, magenta, and a mixture thereof.   6. The planar illumination device according to claim 1, wherein an area occupied by the halftone dots with respect to an area of a surface forming the halftone dots of the optical member is 5% to 95%.   The planar illumination device according to any one of claims 1 to 6, wherein the halftone dot is an aggregate of dots having a quadrilateral shape, a circular shape, a rectangular shape, a triangular shape, a rhombus shape, a star shape, an ellipse shape, or a crescent shape.   The planar illumination device according to any one of claims 1 to 7, wherein the halftone dots are formed in a striped or grid pattern.   The planar illumination device according to claim 1, wherein the pattern forming member generates light having a geometric brightness change. 10. The halftone dot patterns of the two halftone dot pattern forming members are in a non-matching relationship when the halftone dot pattern forming members are overlapped in parallel with the light exit surface of the optical member unit. The planar illumination device according to any one of the above.   The planar illumination device according to any one of claims 1 to 10, wherein the optical member unit includes a prism sheet that improves light collection by improving the condensing property of light emitted from the light exit surface of the light guide plate.   The planar illumination device according to any one of claims 1 to 11, wherein the optical member unit includes a diffusion sheet that diffuses and equalizes light emitted from a light exit surface of the light guide plate.   The planar illumination device according to any one of claims 1 to 12, wherein the optical member unit includes a transmittance adjusting member that reduces luminance unevenness of light emitted from a light exit surface of the light guide plate. A light source;
  A light guide plate that emits light from the light source from a light exit surface;
  An optical member unit that is disposed on the light exit surface of the light guide plate and uniformly emits the light emitted from the light guide plate and exits from the light exit surface;
  A pattern forming member that is disposed on the light exit surface of the optical member unit and that generates light having a regular brightness change composed of interference fringes from uniform light emitted from the light exit surface of the light guide plate And having
  The pattern forming member includes at least one halftone dot pattern forming member in which halftone dots are formed in a regular pattern on the front and back surfaces of a light-transmitting sheet-like optical member,
  At least one of the halftone dot pattern forming members changes the uniform light into light having a regular brightness change composed of the interference fringes.

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