JP2007194128A - Planar lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar lighting system capable of preventing luminance irregularity from occurring in a connection part between illumination units, having a simple structure of the connection part, and having high luminance uniformity as a whole, in a large-sized planar lighting system including two or more illumination units. <P>SOLUTION: This planar lighting system is composed by connecting at least two illumination units each including a linear light source, a light guide plate for diffusing light from the linear light source to emit it from a light emitting surface, and a reflecting member formed along a back surface on the side opposite to the light emitting surface of the light guide plate to each other in the axis direction of the linear light source. The illumination units are connected to each other by shifting them from each other in a direction perpendicular to the axis direction so that the linear light source of the illumination unit and the linear light source of the other illumination unit adjacent to it are positioned on axes different from each other; and, in the connection part, the end of the linear light source is arranged at a position on the side opposite to the light guide plate of the reflecting member of the adjacent illumination unit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  As the liquid crystal display device, a planar illumination device (backlight unit) that irradiates light from the back side of a liquid crystal panel (LCD) and illuminates the liquid crystal panel is used. The same planar lighting device (backlight unit) is also used for billboards on advertising panel advertising towers.

  As an example of such a planar illumination device, two closed spaces arranged in parallel in a structure in which a case main body, a separating member, a transparent plate, and two end lids are combined are defined. In addition, a plug and a socket are provided at both ends of the lamp, and a plurality of lamps are connected in series as required by a user who requires a longer lamp, and the lamp is extended to a required length ( For example, see Patent Document 1).

Further, as another example of the planar illumination device, the light emitting plate main body disposed substantially perpendicular to the illumination light projection direction is arranged on one side of the surface of the light guide plate main body, and on the other side of the surface continuous from the light emitting unit side. The reflective portion 3 that is inclined to the back surface side is formed, and the incident portion is formed on the other side of the back surface corresponding to the reflective portion, and the bright portion that is inclined from the incident portion side to the front surface side is formed on one side of the back surface. The thing is also known (for example, refer patent document 2).
According to this planar illumination device, the base of the discharge fluorescent tube or other light source, the socket component, etc. are covered with the light guide plate main body arranged on the surface side, and the illumination light incident on the light guide plate main body is covered with the light guide plate main body. By emitting the light from the entire surface, it is said that a dark portion due to the base of the light source and the socket component can be completely prevented, and a uniform lighting effect can be obtained over the entire planar lighting device.

  As another example of the planar illumination device, a light source for illumination, a light guide plate that diffuses light emitted from the light source and irradiates the object to be illuminated, and is further emitted from the light guide plate. Some of them are configured using components such as a prism sheet and a diffusion sheet that make uniform light. Such a planar illumination device can provide high-quality light having a more uniform luminance distribution as compared with a device that covers a large number of linear light sources with a simple light diffusion plate.

Utility Model Registration No. 3055721 JP-A-10-104436

  In recent years, there has been a demand for thinner planar lighting devices and lower power consumption, and a larger planar lighting device. Since the planar illumination device described in Patent Document 1 is provided with plugs and sockets at both ends thereof, the lamp can be extended to a required length by being connected in the longitudinal direction of the light source. However, since there is a case (end lid) at the connecting portion, there is a problem that luminance unevenness occurs. Further, although it can be extended in the longitudinal direction of the light source, it cannot be extended in a direction perpendicular to the longitudinal direction of the light source, and there is a problem that the expandability is low.

  Moreover, since the planar illumination device described in Patent Document 2 uses a member such as a refraction prism that covers a base of a discharge tube or other light source or a socket component in order to prevent unevenness in illuminance, the number of parts increases. There are problems such as a complicated structure and an increase in the thickness of the entire planar lighting device.

  Here, it is an effective method to use a light guide plate in order to provide a high-quality planar illumination device having a uniform luminance distribution. However, when a light guide plate is used, it is difficult to increase the size with a single light guide plate. Therefore, the size is increased by connecting a plurality of illumination units, which are constituent units of the planar illumination device including the light guide plate or the light guide plate and the light source. At this time, there is a problem that luminance unevenness occurs due to light scattering at the connection portion or influence of an unstable luminance region at the light source end if the connection is simply made.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to connect between illumination units in a large planar illumination device configured by connecting two or more illumination units. It is an object of the present invention to provide a planar illumination device that does not cause luminance unevenness in the portion and has a simple configuration in the connecting portion and has high luminance uniformity as a whole.

  In order to solve the above problems, the present invention provides at least two illumination units including a linear light source and a reflecting member having a light reflecting surface that reflects light from the linear light source toward a light emitting surface. A planar illumination device connected in an axial direction of a linear light source, wherein the adjacent illumination units are shifted from each other in a direction orthogonal to the axial direction (that is, the linear light source of one illumination unit and the other And the end of the linear light source is disposed on the opposite side of the light reflecting surface of the reflecting member of the adjacent lighting unit. A planar illumination device is provided.

Here, it is preferable that a light guide plate is disposed on the light reflecting surface side of the reflecting member.
The light guide plate includes a rectangular light exit surface and one or more parallel grooves for housing the linear light source on a surface opposite to the light exit surface, and is perpendicular to the axis of the linear light source. Including at least one unit structure in a direction perpendicular to the light emitting surface in a direction perpendicular to the parallel grooves in the direction perpendicular to the light emitting surface in a direction perpendicular to the parallel grooves. A planar illumination device that diffuses incident light and emits the light from the light exit surface is preferable.

  Further, it is preferable that the adjacent illumination units are connected in the axial direction of the linear light source at a position shifted by a half distance of the unit structure in the orthogonal direction.

  In the planar illumination device of the present invention, the adjacent illumination units are connected to each other in a direction orthogonal to the axial direction, thereby connecting the linear light source of one illumination unit and the linear shape of the other illumination unit adjacent to each other. Place the light source on a different axis. Furthermore, the edge part of a linear light source is arrange | positioned on the opposite side of the light reflection surface of the reflection member of an adjacent illumination unit. Accordingly, the planar illumination device having high luminance uniformity at the connection portion can be prevented by preventing the light emitted from the wiring portion at the end of the linear light source and the luminance unstable region from affecting the luminance distribution. Can be provided.

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 an exploded perspective view showing an embodiment of the planar lighting device of the present invention. FIG. 4A is a partial cross-sectional view showing a cross section including the first illumination unit 21a in the embodiment of the planar illumination device shown in FIG. 3, and FIG. 4B is a cross section including the second illumination unit 21b. It is a fragmentary sectional view shown. FIG. 6 is a schematic rear view illustrating the positional relationship between the linear light source and the reflecting member, as seen from the side opposite to the light guide plate. 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. 7) for lighting the plurality of linear light sources 12.

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 rectangular light exit surface 22a is formed on the exit surface 14a side, and a plurality of parallel grooves 22b for accommodating the plurality of linear light sources 12 are formed on the back side thereof, and between the adjacent parallel grooves 22b, the light exit surface 22a side is formed. The thinnest portion 22c having the thinnest thickness toward the back side is formed, and the plurality of linear light sources 12 are disposed along the light guide plate 22 disposed in each of the parallel grooves 22b and the back surface 22d of the light guide plate 22. The first lighting unit 21a and the second lighting unit 21b having the reflecting member 26, and the first lighting unit 21a and the second lighting unit 21b are arranged below the first lighting unit 21a and the second lighting unit 21b. The first lighting unit 21a, the second lighting unit 21b, and the base 28 are covered with the base 28 that holds 21b and the two first lighting units 21a and the second lighting unit 21b connected in the axial direction of the linear light source 12. And a diffusion plate 29.
FIG. 5B shows only the unit light guide plate 23 having one parallel groove 22b which is one unit constituting the light guide plate 22, but FIG. 4A and FIG. As shown, the first lighting unit 21 a and the second lighting unit 21 b are formed by a light guide plate 22 including a plurality of unit light guide plates 23.

  The linear light source 12 is disposed in a plurality of parallel grooves 22b of the light guide plate 22 so as to maintain an appropriate distance between the light guide plate 22 and the reflection plate 26 using the silicon ring 24, and the inverter unit 18 and the linear light source 12, respectively. It is connected. The linear light source 12 used in the present invention is a cold cathode tube (CCFL: see FIG. 7) that is linear, that is, a thin rod, 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.

Further, both ends of the linear light source 12 are wired to connect the linear light source 12 and the inverter unit 18, and a cap 40 is attached to the wired end. The cap 40 is formed of silicon rubber, and a wire 42 for connecting the linear light source 14 and the inverter unit 18 is extended from the inverter unit 18 inside thereof. The linear light source 12 and the wire 42 may be connected by using a method such as soldering or pressure bonding.
In addition, about the detailed arrangement | positioning (refer FIG.3, FIG.4 and FIG.6) of the linear light source 12, and about the inverter unit 18 and the power supply 38 (refer FIG. 7) which turn on and off the some linear light source 12, It 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 formed of a transparent resin, and as shown in FIG. 5B, a rectangular individual light emitting 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 paragraphs [0036] to [0039] of Japanese Patent Application Laid-Open No. 2005-23497 related to the applicant's application can be applied. .

  Here, the 1st illumination unit 21a shown to Fig.4 (a) is provided with the five linear light sources 12 as an example, and the 2nd illumination unit 21b shown in FIG.4 (b) is four as an example. The linear light source 12 is provided. The first lighting unit 21a and the second lighting unit 21b have basically the same configuration, although the shapes of the light guide plate 22 and the reflecting member 26 differ depending on the number of linear light sources.

The parallel grooves 22b may have a triangular shape as shown in the figure, but any other shape that has an effect of uniforming the luminance such as two hyperbolic shapes, U-shapes, and parabolic shapes that intersect is also possible. However, for example, what is disclosed in paragraphs [0040] to [0058] of Japanese Patent Application Laid-Open No. 2005-23497 related to the applicant's application 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 accommodated in the parallel groove 22b to enter and is inclined in a direction parallel to the individual light emitting surface 23a from the thick portion 23b toward the thin end portion 23c. The illumination light propagated in the back surface portion 23e and the illumination light reflected from the inclined surface 23d and the reflecting member 26 arranged along the inclined surface 23d that forms 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 emitting 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 c 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.

The reflection member 26 is for improving the utilization efficiency of the illumination light emitted from the linear light source 12, and is disposed along the back surface 22 d of the light guide plate 22. However, at the position where the parallel grooves 22b are formed, the linear light source 12 is sandwiched between the reflecting member 26 and the light guide plate 22 in parallel with the lower housing 30 and the parallel grooves 22b of the light guide plate 22 are blocked. The light source 12 is disposed on the back surface. The reflecting member 26 reflects light leaking from the back surface of the light guide plate 22 and makes it incident on the light guide plate 22 again. Further, the light is reflected from the lower surface of the linear light source 12, and the reflected light is incident from the side wall surface of the parallel groove 22 b of the light guide plate 22.
In the illustrated example, one reflection member 26 is provided for the light guide plate 22 including a plurality of unit light guide plates 23, but a separate reflection member may be provided for each unit light guide plate 23.

  Here, the planar illumination device 10 according to the present invention has a simple configuration when connecting the first illumination unit 21a and the second illumination unit 21b in the axial direction of the linear light source 12, as described above. This prevents occurrence of luminance unevenness in the connection portion. Hereinafter, this point will be described in detail.

As shown in FIG. 3 and FIG. 6, in the illuminating device main body 14 according to the present invention, in the connection portion that connects the first illumination unit 21 a and the second illumination unit 21 b, the end portion of the linear light source on the connection portion side Is disposed in the gap 44 formed between the reflecting member 26 and the base 28 of the adjacent lighting unit (on the back surface side of the reflecting member 26), thereby preventing luminance unevenness from occurring in the connecting portion. Here, the gap 44 is a space formed below the thinnest portion 22 c between the parallel grooves 22 b of the light guide plate 22.
That is, for example, the length of the unit light guide plate 23 in the direction perpendicular to the axis of the linear light source 12 is set so that the end of the linear light source 12 of one illumination unit is positioned in the gap 44 of the other illumination unit. The first illumination unit 21a and the second illumination unit 21b adjacent to each other are formed so that two illumination units are shifted from each other in the direction perpendicular to the axis of the linear light source 12 by one half pitch as one pitch.

In this way, the linear light sources 12 of the two illumination units (the first illumination unit 21a and the second illumination unit 21b) are alternately arranged so that the luminance at the end of each linear light source 12 is unstable or a cap A region where the luminance of the linear light source 12 is stabilized by accommodating the wiring portion to which the light source 40 is attached, that is, the end of the linear light source 12 causing uneven luminance, in the gap 44 on the back surface side of the reflecting member 26. Only the emitted light from can be used, and luminance unevenness due to a decrease in luminance or the like at the connection portion can be prevented.
Further, in the present invention, it is not necessary to provide a new member to prevent the luminance unevenness, and the luminance unevenness can be prevented with a simple configuration.

In the present embodiment, the gap between the illumination units is set to a half pitch, but the present invention is not limited to this, and the end of the linear light source may be disposed on the back surface side of the reflecting member of the adjacent illumination unit. I can do it.
Further, in order to configure the planar illumination device as described above, it is preferable that the length of the linear light source 12 in the axial direction is longer than that of the light guide plate 22 or the reflection member 26. Thereby, the wiring portions at both ends of the linear light source 12 and the region where the luminance is unstable can be accommodated in the gap 44 or the upper housing 32 to be described later to prevent luminance unevenness.

  Here, in FIG. 6, two adjacent reflecting members 26 are arranged in contact with each other at the connection portion, but the present invention is not limited to this, and a gap is provided between the two reflecting members 26. Also good.

  The diffusion plate 29 diffuses and equalizes the illumination light emitted from the light exit surface 22a of the light guide plate 22. The first illumination unit 21a and the second illumination unit 21b connected in the axial direction of the light source 12 are supported on the base 28, and a diffusion plate 29 is disposed so as to cover the illumination unit 14 and the base 28 from above. . The diffusion plate 29, the light guide plate 22, and the base 28 are formed with screw holes and are screwed together.

As shown in FIG. 3, the base 28 is provided with a through hole 45 for allowing the wire 42 to pass therethrough. As shown in FIG. 6, a space that has not been used in the past, such as storing a linear light source in a gap 44 formed between the reflecting member 26 and the base 28, or allowing the wire 42 to pass through, is effectively used. Thus, the planar illumination device can be thinned.
The illumination device body 14 is basically configured as described above.

  On the other hand, as shown in FIG. 4, the housing 16 accommodates and supports the lighting device main body 14, and is sandwiched and fixed from the light emitting surface 14 a 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. And 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. Although not shown in FIG. 4, 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.
By arranging the folding member 34 in this way, the rigidity of the housing 16 can be increased, and light can be emitted uniformly and efficiently, while 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.

In addition, the housing 16 has a fastener such as an L-shaped metal fitting that joins the four corners, the light emitting surface 14a of the diffusion plate 29 of the planar device main body 14, and the periphery of the opening 16a of the upper housing 32. An elastic member made of an elastic material such as rubber or a protective member that protects the entire upper surface of the diffusion plate 29 of the planar apparatus main body 14 may be provided between the two portions.
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. 7A and 7B 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. 7B 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. Instead, a space may be provided between the lower housing 30 and the upper housing 32 in the periphery of the opening 16a of the housing 16 to form an inverter housing portion, and a plurality of inverter units may be housed. 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.

  In the planar illumination device 10 of the present invention, a diffusion member may be provided on the light exit surface 22a of the light guide plate 22 in order to make the luminance uniform. As the diffusing member, a sheet-like member that is partially roughened (matted) according to the luminance distribution on the surface of the light guide plate 22 or that has a halftone dot pattern formed by a color material or the like (hereinafter, halftone dot sheet). Etc.) can be used. Moreover, you may give the process which gives these characteristics to the surface of the light-guide plate 23 (22). For example, a halftone dot pattern may be formed on the light exit surface 22a.

Moreover, although the illuminating device main body 14 is provided with the diffusion plate 29, the uniform illumination light emitted from the light emitting surface 22a is made more uniform, and the uniformity is further improved from the light emitting surface 14a of the illuminating device main body 14. In order to emit the illumination light, various optical members may be provided on the light emission surface 22a of the light guide plate 22 or the like.
For example, a microprism array parallel to the parallel grooves 22b of the light guide plate 22 constituting the light output surface 14a is formed, and the brightness of the illumination light emitted from the light output surface 22a of the light guide plate 22 is enhanced to increase brightness. It is used to reduce the luminance unevenness of the prism sheet to be improved and the illumination light emitted from the light emitting surface 22a of the light guide plate 22, and is disposed on the transparent film and the surface according to the luminance unevenness. And a transmittance adjusting member including a large number of transmittance adjusting bodies.

  The transmittance adjusting member is preferably provided on the side closer to the light emitting surface 22a of the light guide plate 22, but the arrangement order and number of the prism sheets are not limited, and the prism used in the optical member unit is not limited. The sheet and the transmittance adjusting member are not limited to those described above, and any optical member can be used as long as the illumination light emitted from the light emitting surface 22a of the light guide plate 22 can be made more uniform. May be. The prism sheet 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.

Moreover, although the planar illumination device 10 of the present invention is provided with the diffusion plate 29, a member having the same shape as the diffusion plate 29 is formed of a material having no transparent diffusion action, and the prism sheet and the transmittance adjustment member are formed on the prism sheet and the transmittance adjustment member. In addition, a diffusion sheet may be further provided.
For optical members such as a prism sheet, a diffusion sheet, and a transmittance adjusting member, those disclosed in paragraphs [0028] to [0033] of Japanese Patent Application Laid-Open No. 2005-23497 related to the applicant's application should be applied. Can do.

  In the planar lighting device 10 of the present invention configured as described above, the first lighting unit 21a and the second lighting unit 21a and the second lighting unit 21a are accommodated by accommodating the end of the linear light source in the gap 44 between the reflecting member 26 and the base 28. The light guide plate can be extended in the axial direction of the linear light source 12 without luminance unevenness at the connection portion with the illumination unit 21b. Further, the planar illumination device 10 can be thinned by effectively using the space through the wiring 44 between the reflecting member 26 and the base 28.

  In the illustrated example, the example in which two illumination units are connected in the axial direction has been described in detail. However, the present invention is not limited to this, and similarly, for example, the first illumination unit 21a and the second illumination unit 21b. Can be alternately arranged, and a plurality of illumination illumination units can be connected in the axial direction to increase the size of the planar illumination device.

By the way, in the planar illumination device 10 of the present invention, in addition to increasing the size of the linear light source 12 in the axial direction, the illumination device body 14 of the illustrated example is connected in a direction perpendicular to the axial direction (hereinafter referred to as parallel connection). Thus, it can be a large illuminating surface. Hereinafter, a configuration that can be suitably used for parallel connection will be described.
In the following description, in order to make the description easy to understand, the structure of the illuminating device main body 14 constituting the planar illuminating device 10 is schematically shown in a shape as shown in FIG.

  That is, in the following description, the illuminating device main body 14 is linearly connected to the inverter unit (not shown) via the drive circuit 18a from the light guide plate support member 36 having the reflection member 26 and the power source 38 in the housing. The light source 12 and the light guide plate 23 (22) are stacked in order from below.

  By the way, when the above-mentioned illuminating device main body 14 is connected in parallel as it is (see FIG. 10B), as shown in FIG. As a result, a decrease in luminance occurs. This is influenced by the reflection of light generated on the end surface (inner surface) of the light guide plate of the illuminating device main body 14.

  On the other hand, in one embodiment of the present invention shown in FIG. 8, the portions that contact each other when the light guide plate 23 (22) of the lighting device main body 14 is connected have dimensions that are cut off at least by a predetermined dimension. Is. Here, the dimension a in FIG. 8B indicates the arrangement interval of the linear light sources 12 in the basic structure of the light guide plate 23 (22) of the illuminating device body 14, and the dimension b is the light guide plate 23 (22). The arrangement | positioning space | interval of the linear light source 12 after cutting down the dimension of the end surface part of is shown.

The amount of trimming of this dimension is performed so as to compensate for the above-described decrease in luminance, as will be described below.
That is, when the dimensions are cut off at the connection portion of the light guide plate 23 (22) of the illuminating device main body 14, when the connection is made after the dimensions are cut down, the connection portion reflects light inside as described above. Even if a decrease in brightness occurs, the brightness is improved enough to make up for it.

  Actually, as shown by a circle B in FIG. 8 (b), the dimensions are cut down so that the luminance is slightly higher at the connection portion than the other portions (shown by broken lines). The increase is preferably distributed by using a member such as a diffusion sheet 25 having a diffusivity pattern corresponding to the above-described luminance increase pattern so that the luminance is uniform as a whole. . As such a diffusion sheet 25, the surface of the light guide plate 23 (22) is partially roughened (matted) corresponding to the above-described luminance increase pattern, or various types of sheets such as a halftone dot sheet. Is available. Moreover, you may give the process which gives these characteristics to the surface of the light-guide plate 23 (22).

As described in detail, according to the present invention, without providing a new member in order to prevent luminance unevenness, the surface illumination device is extended in the axial direction of the linear light source, and the luminance is reduced with a simple configuration. A large planar lighting device without unevenness can be provided.
Furthermore, according to a more preferable aspect of the present invention, the planar illumination device can be extended two-dimensionally by extending the planar illumination device in the direction perpendicular to the axis, and the light emitting surface of the planar illumination device can be obtained. It is possible to provide a large planar lighting device having a uniform luminance distribution with no luminance unevenness.
Further, according to the present invention, when a planar lighting device is enlarged, a plurality of sizes are provided by providing a planar lighting device having a desired size by connecting a plurality of lighting units as a unit structure of the planar lighting device. Therefore, it is possible to reduce the cost, improve the yield, and facilitate the manufacturing.

  The planar lighting device according to the present invention has been described in detail above. However, the present invention is not limited to the above-described embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

For example, the planar lighting device of the illustrated example includes the light guide plate, but is not limited thereto, and may not include the light guide plate, for example, may include only the diffusion plate. Also in this case, in the connecting portion, the optical axis of the linear light source is arranged so as to be shifted, and the region where the luminance of the end of the linear light source is unstable is arranged on the opposite side of the light reflecting surface of the reflecting member, Luminance unevenness due to the end of the linear light source can be prevented.
Further, in the planar illumination device using the light guide plate according to the present invention, the shape of the light guide plate is not limited to the exemplified one, and the characteristics of the thickness change in the direction parallel to the linear light source are particularly It is not limited.

  Further, instead of the linear light source 12 used in the planar illumination device shown in FIG. 1, a linear light source (array light source) formed by continuously arranging light emitting elements such as LEDs in a linear form is used. The present invention can also be suitably applied to a conventional planar lighting device.

  As described above, the planar illumination device using such a light source is not limited to the direction in which a plurality of light sources in which the light emitting elements are arranged in a line is arranged in the size of the surface of the planar illumination device. It is also possible to obtain an effect that the light emitting elements can be easily expanded in the arrangement direction of the light emitting elements.

  Furthermore, for uniformizing the luminance of the emitted light at the connection portion, in addition to the method shown in the above embodiment, another light emitter (linear light source, point light source, etc.) is provided in the vicinity of the connection portion of the illumination device main body 14 described above. ), A method of increasing the brightness of only the linear light source close to the connection part (by changing the light source shape, increasing the wattage, etc.), and increasing the reflection efficiency of the reflection member near the connection part For example, a method of reducing the diffusion degree of the diffusion plate added to the light guide plate only in the vicinity of the connection portion (that is, reducing the concentration of diffusion particles in the diffusion plate) is effective.

  In addition, it is needless to say that the above-described technique is not limited to application to a planar planar illumination device, and can also be applied to a curved illumination device. For example, it can also be suitably used for an illumination device (such as a backlight for a signboard) that is wound around a cylinder.

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 disassembled perspective view which shows one Embodiment of the illuminating device main body which concerns on this invention. (A) is a fragmentary sectional view which shows the cross section containing the 1st illumination unit in one Embodiment of the planar illuminating device shown in FIG. 1, (b) is a fragmentary sectional view which shows the cross section containing a 2nd illumination unit. It is. (A) is a schematic perspective view of the light-guide plate used for the planar illuminating device shown in FIG. 4, (b) is a diagram which shows the cross-sectional shape of one unit light-guide plate of an illuminating device main body. It is a typical back view explaining the positional relationship of a linear light source and a reflecting plate. (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. BRIEF DESCRIPTION OF THE DRAWINGS The planar illuminating device which concerns on one Embodiment of this invention is shown, (a) is a graph which shows luminance distribution, (b) is a perspective view which shows schematic structure. It is the modeled perspective view which shows the basic composition of an illuminating device main body. FIGS. 3A and 3B show a situation where the lighting device main body shown in FIG. 2 is connected as it is, in which FIG. 3A is a graph showing a luminance distribution, and FIG. 3B is a perspective view showing a schematic configuration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Planar illuminating device 12 Linear light source 14 Illuminating device main body 14a Light emission surface 16 Housing | casing 16a Opening part 18 Inverter unit 18a Drive circuit 18b Transformer 18c Tube current detection circuit 18d Voltage control oscillation circuit 20 Inverter accommodating part 21a 1st illumination unit 21b 2nd illumination unit 22 Light guide plate 22a Light exit surface 22b Parallel groove 22c Thinnest part 22d Back 23 Unit light guide plate 23a Individual light emission surface 23b Thick part 23c Thin end part 23d Inclined surface 23e Inclined back part 24 Silicon ring 25 Diffusion sheet 26 Reflecting member 28 Base 29 Diffusion plate 30 Lower housing 32 Upper housing 34 Folding member 36 Light guide plate support member 37 Drive device 38 Power supply 40 Cap 42 Wire 44 Gap 45 Through hole

Claims (4)

Planar illumination for connecting at least two illumination units in the axial direction of the linear light source including a linear light source and a reflecting member having a light reflecting surface that reflects light from the linear light source toward the light exit surface A device,
The adjacent lighting units are connected with being shifted from each other in a direction orthogonal to the axial direction,
The planar illumination device, wherein an end of the linear light source is disposed on the opposite side of the light reflection surface of the reflection member of an adjacent illumination unit.   The planar lighting device according to claim 1, wherein a light guide plate is disposed on a light reflecting surface side of the reflecting member.   The light guide plate includes a rectangular light exit surface and one or more parallel grooves for housing the linear light source on a surface opposite to the light exit surface, and a surface perpendicular to the axis of the linear light source. One or more unit structures whose thickness in the direction perpendicular to the light exit surface decreases in the direction perpendicular to the parallel groove in the direction perpendicular to the parallel groove is incident in the direction perpendicular to the parallel groove and incident from the linear light source The planar illumination device according to claim 2, wherein light is diffused and emitted from the light exit surface.   The planar illumination device according to claim 3, wherein the adjacent illumination units are connected in the axial direction of the linear light source at a position shifted by a half distance of the unit structure in the orthogonal direction.

Images